NL2036305B1

NL2036305B1 - Bicycle transmission system

Info

Publication number: NL2036305B1
Application number: NL2036305A
Authority: NL
Inventors: Marie Van Druten Roëll
Original assignee: Classified Cycling Bv
Priority date: 2023-02-27
Filing date: 2023-11-17
Publication date: 2024-09-09
Also published as: NL2036303B1

Abstract

The disclosure relates to a bicycle transmission, comprising an axle, such as a Wheel axle or a layshaft in a crank transmission, configured to be non- rotataby ﬁxed to a frame of the bicycle; at least one sun gear rotatably mounted around the axle; at least one clutch mechanism for selectively preventing rotation of the at least one sun gear in at least one rotational direction about the axle; and a camshaft mounted inside the axle for actuating the at least one clutch mechanism

Description

P135539NL00

Title: Bicycle transmission system

FIELD

The invention relates to a bicycle transmission system, such as for a bicycle.

BACKGROUND

Bicycle transmission systems are known per se. Many bicycle transmission systems are configured to provide a plurality of different transmission ratios.

A known class of bicycle transmission systems is based on a chain connecting a front chain wheel and a rear sprocket, wherein the rear sprocket is one of a plurality of rear sprockets, e.g. combined in a cassette, and a rear derailleur is provided for providing selectable different transmission ratios. Alternatively, or additionally, the front chain wheel is one of a plurality of front chain wheels, and a front derailleur is provided for providing selectable different transmission ratios.

Another known class of bicycle transmission systems uses encased transmissions. Such encased transmissions can e.g. be internally geared bicycle hub transmissions. Such encased transmissions can be internally geared crank units. The encased transmissions can be used in combination with a derailleur system.

Present encased transmission systems can have the disadvantage of having few different transmission ratios. Present encased transmission systems with more transmission ratios often have the disadvantage of being heavy.

SUMMARY

It is an object to propose an improved bicycle transmission for a human powered vehicle or light electric vehicle.

According to an aspect 1s provided a bicycle transmission comprising an axle. The axle can e.g. be a wheel axle. The transmission can be an internally geared hub transmission. The axle can e.g. be a shaft, such as a layshaft, in a crank transmission. The transmission can be a crank transmission unit. The axle is configured to be fixed against rotation. The axle can e.g. be non-rotataby fixed to a frame of the bicycle. The transmission comprises at least one sun gear rotatably mounted around the axle. The transmission comprises at least one clutch mechanism for selectively preventing rotation of the at least one sun gear in at least one rotational direction about the axle. The transmission comprises a camshaft mounted inside the axle for actuating the at least one clutch mechanism.

Mounting the camshaft inside the axle can provide for efficient actuation of the at least one clutch mechanism.

Optionally, the transmission comprises an electromechanical actuator, such as an electric motor, configured for moving, such as rotating, the camshaft. The electromechanical actuator, such as the electric motor, can be positioned on or in the axle. Providing the electromechanical actuator in the axle can aid in providing design freedom for the transmission.

Optionally, the at least one sun gear comprises a plurality of sun gears rotatably mounted around the axle. Optionally, the at least one clutch mechanism comprises a plurality of clutch mechanisms. The plurality of clutch mechanisms can be configured for selectively preventing rotation of one or more of the plurality of sun gears in at least one rotational direction about the axle. Optionally each clutch mechanism of the plurality of clutch mechanisms is configured for selectively preventing rotation of an associated one of the plurality of sun gears in at least one rotational direction about the axle. Optionally, the camshaft comprises a single notch profile for actuating the plurality of clutch mechanisms.

According to an aspect 1s provided a bicycle transmission comprising an axle. The transmission comprises a clutch mechanism surrounding and/or inside the axle The transmission comprises an electromechanical actuator, such as an electric motor, in the axle and configured for actuating the clutch mechanism. The axle can e.g. be a wheel axle. The transmission can be an internally geared hub transmission. The axle can e.g. be a shaft, such as a layshaft, in a crank transmission. The transmission can be a crank transmission unit.

Optionally, the transmission comprises a camshaft configured to be moved by the electromechanical actuator, the camshaft being configured for actuating the clutch mechanism. The camshaft can be mounted inside the axle.

Optionally, the axle is configured to be fixed against rotation. The axle can e.g. be non-rotataby fixed to a frame of the bicycle. The transmission can further comprise at least one sun gear rotatably mounted around the axle, wherein the clutch mechanism is configured for selectively preventing rotation of the at least one sun gear in at least one rotational direction about the axle.

Optionally, the at least one sun gear comprises a plurality of sun gears rotatably mounted around the axle. Optionally, the transmission comprises a plurality of clutch mechanisms. The plurality of clutch mechanisms can be configured for selectively preventing rotation of one or more of the plurality of sun gears in at least one rotational direction about the axle. Optionally each clutch mechanism of the plurality of clutch mechanisms is configured for selectively preventing rotation of an associated one of the plurality of sun gears in at least one rotational direction about the axle. Optionally, the camshaft comprises a single notch profile for actuating the plurality of clutch mechanisms.

According to an aspect 1s provided a bicycle transmission comprising an axle. The axle can e.g. be a wheel axle. The transmission can be an internally geared hub transmission. The axle can e.g. be a shaft, such as a layshaft, in a crank transmission. The transmission can be a crank transmission unit. The axle is configured to be fixed against rotation. The axle can e.g. be non-rotataby fixed to a frame of the bicycle. The transmission comprises a plurality of sun gears rotatably mounted around the axle. The transmission comprises a plurality of clutch mechanisms for selectively preventing rotation of one or more of the plurality of sun gears in at least one rotational direction about the axle. The transmission comprises a camshaft comprising a single notch profile for actuating the plurality of clutch mechanisms. The singe notch profile can comprise a cam, or a plurality of cam sections, extending along an axial direction of the camshaft.

The singe notch profile, e.g. the cam, or the plurality of cam sections, can extend along a line parallel to a central axial axis of the camshaft.

Optionally, the camshaft is mounted inside the axle.

Optionally, the transmission comprises an electromechanical actuator, such as an electric motor, configured for moving, such as rotating, the camshaft. The electromechanical actuator, such as the electric motor, can be positioned on or in the axle.

For the transmission according to any of the above aspects the following can apply.

Optionally, each clutch mechanism comprises at least one pawl configured to be actuated by the camshaft, such that the at least one pawl is selectively in engagement or in disengagement with the respective sun gear.

The pawl in engagement with the respective sun gear can selectively prevent rotation of the respective sun gear in at least one rotational direction about the axle.

Optionally, the at least one pawl is configured to move in radial direction relative to the axle. The pawl can engage the respective when in a radially outward position. The pawl can be disengaged from the respective sun gear when in a radially inward position.

Optionally, each clutch mechanism has a selection bush associated therewith. The camshaft can comprises one or more grooves for axially moving the selection bush(es).

Optionally, the comprising a resilient member, such as a compliant mechanism, connecting the camshaft to the electromechanical actuator. The resilient member can be pre-tensioned in two opposite directions.

Optionally, the transmission comprises an electric drive for 5 propelling, or assisting in propelling, the bicycle. The electric drive can be mounted concentrically inside and/or outside the axle. The electric drive may e.g. be mounted concentrically to the central axis of a hub transmission comprising the bicycle transmission. The electric drive can be mounted on a further axle, such as parallel to the axle. The electric drive may e.g. be mounted concentrically a crank axis of a crank transmission comprising the bicycle transmission. Optionally, the electric drive comprises an electric motor. Optionally, the electric drive comprises a planetary gear set.

Optionally, the camshaft or the electric drive comprises a rotation sensor and/or a position sensor.

Optionally, the transmission comprises control electronics for controlling the electromechanical actuator. The control electronics can be mounted distally from a drive side or non drive side hub bearing.

According to an aspect is provided a bicycle transmission, for instance according to any of the above aspects, comprising a hub shell for connection to a bicycle wheel. The transmission comprises a wheel axle. The transmission comprises a driver part configured for connection to one or more sprockets. The driver part is mounted to the wheel axle via a first bearing. The hub shell is mounted to the wheel axle via a second bearing and to the driver part via a third bearing. The transmission comprises a transmission system providing a plurality of selectable different transmission ratios between the driver and the hub shell. The transmission system is positioned between the second and third bearings. The transmission comprises an electromechanical actuator for actuating a gear shift from one transmission ratio to another. The transmission comprises control electronics for controlling the electromechanical actuator. The control electronics are positioned beyond the second bearing when seen from the transmission system.

According to an aspect is provided a bicycle transmission, for instance according to any of the above aspects, comprising a hub shell for connection to a bicycle wheel. The transmission comprises a wheel axle. The transmission comprises a driver part for connection to one or more sprockets, wherein the driver part is mounted to the wheel axle via a first bearing, and wherein the hub shell is mounted to the wheel axle via a second bearing and to the driver part via a third bearing, wherein the hub shell encloses a first cavity between the second bearing and the third bearing. The transmission comprises a transmission system providing a plurality of selectable different transmission ratios between the driver and the hub shell, the transmission system being positioned in the first cavity.

The transmission comprises an electromechanical actuator for actuating a gear shift from one transmission ratio to another. The transmission comprises control electronics for controlling the electromechanical actuator.

The control electronics are positioned outside the first cavity.

Optionally, the hub shell extends beyond the second bearing when seen from the transmission system and encases the control electronics.

Optionally, the control electronics are mounted, e.g. immobile, on the axle, such as concentrically on the axle.

Optionally, the control electronics comprise at least one of a generator, battery, PCB, wireless receiver/transmitter, antenna, LED, charge plug, connector, or micro-chip.

Optionally, the control electronics is mounted inside, behind and/or connected to a plastic housing.

Optionally, the hub shell comprises an inner hub shell housing the axle and an outer hub shell configured for connection to, e.g. a rim of, a wheel, e.g. via spokes. Optionally, the control electronics are positioned to be replaceable after removing the inner hub shell from the outer hub shell.

According to an aspect 1s provided a bicycle transmission comprising an axle. The axle can e.g. be a wheel axle. The transmission can be an internally geared hub transmission. The axle can e.g. be a shaft, such as a layshaft, in a crank transmission. The transmission can be a crank transmission unit. The axle has a central axis, extending longitudinally of the axle. The axle can be configured to be fixed against rotation. The axle can e.g. be non-rotataby fixed to a frame of the bicycle. The transmission comprises at least one sun gear rotatably mounted around the axle. The transmission comprises at least one clutch mechanism configured for in a first mode selectively preventing rotation of the at least one sun gear in a first rotational direction about the axle, and in a second mode selectively preventing rotation of the at least one sun gear in an opposite second rotational direction about the axle. The transmission comprises a camshaft mounted inside the axle for actuating the at least one clutch mechanism.

Each clutch mechanism comprises a first pawl and a second pawl configured to be actuated by the camshaft, such that the first pawl is selectively in engagement with the respective sun gear in the first mode, and the second pawl is selectively in engagement with the respective sun gear in the second mode. This provides the advantage that the sun gear can be selectively blocked against rotation in two different rotational directions. Hence, transfer of torque to the sun gear can be selectively effected in two different rotational directions.

Optionally, the transmission comprises a further sun gear and a further clutch mechanism. The further clutch mechanism can comprise a third pawl configured to be actuated by the camshaft, such that the third pawl is selectively in engagement with the further sun gear in a third mode.

Optionally, the first and second pawls are configured for each pivoting about a respective pivot axis.

Optionally, the at least one clutch mechanism comprises a plurality of clutch mechanisms. Optionally, in each clutch mechanism, the first and second pawls are configured for each pivoting about a respective pivot axis.

Optionally, a radial distance between the pivot axis and the central axis is different for different clutch mechanisms of the plurality of clutch mechanisms. This provides the advantage that a larger radial distance can be chosen for clutch mechanisms that should transfer higher torque.

Optionally, the at least one sun gear is a plurality of sun gears.

Optionally the axle has a different outer radius at positions of different sun gears of the plurality of sun gears. Optionally, the sun gears have an inner radius corresponding with the outer radius of the axle. This provides the advantage that a larger diameter can be chosen for portions of the axle and sun gears that should transfer higher torque.

Optionally, a first position of the first and second pawls of at least one of the clutch mechanisms is rotated about the central axis relative to a second position of the first and second pawls of at least another one of the clutch mechanisms. Hence, the clutch mechanism may be actuated by a camshaft comprising a single notch profile for actuating the plurality of clutch mechanisms. The singe notch profile can comprise a cam, or a plurality of cams, extending along an axial direction of the camshaft. The singe notch profile, e.g. the cam, or the plurality of cams, can extend along a line parallel to a central axial axis of the camshaft.

According to an aspect 1s provided a bicycle transmission comprising and axle. The axle can e.g. be a wheel axle. The transmission can be an internally geared hub transmission. The axle can e.g. be a shaft, such as a layshaft, in a crank transmission. The transmission can be a crank transmission unit. The axle has a central axis, extending longitudinally of the axle. The axle can be configured to be fixed against rotation. The axle can e.g. be non-rotataby fixed to a frame of the bicycle. The axle can be used to support torque from the sun gears onto the frame. The transmission comprises a plurality of sun gears rotatably mounted around the axle. The transmission comprises a plurality of clutch mechanism for selectively preventing rotation of one or more of the plurality of sun gears in at least one rotational direction about the axle. The transmission comprises a camshaft mounted inside the axle for actuating the plurality of clutch mechanisms. Each clutch mechanism comprises at least one pawl configured to be actuated by the camshaft, such that the at least one pawl is selectively in engagement or in disengagement with the respective sun gear, the at least one pawl being configured for pivoting about a pivot axis. A radial distance between the pivot axis and the central axis is different for different clutch mechanisms of the plurality of clutch mechanisms.

Optionally, the axle has a different outer radius at positions of different sun gears of the plurality of sun gears.

Optionally, a first position of the at least one pawl of at least one of the clutch mechanisms is rotated about the central axis relative to a second position of the at least one pawl of at least another one of the clutch mechanisms.

Optionally, for each clutch mechanism the at least one pawl comprises a first pawl and a second pawl configured to be actuated by the camshaft, such that the first pawl is selectively in engagement with the respective sun gear in the first mode, and the second pawl is selectively in engagement with the respective sun gear in the second mode. Each clutch mechanism can be configured for in the first mode selectively preventing rotation of the at least one sun gear in the first rotational direction about the axle, and in the second mode selectively preventing rotation of the at least one sun gear in the opposite second rotational direction about the axle.

According to an aspect 1s provided a bicycle transmission, comprising an axle. The axle can e.g. be a wheel axle. The transmission can be an internally geared hub transmission. The axle can e.g. be a shaft, such as a layshaft, in a crank transmission. The transmission can be a crank transmission unit. The axle has a central axis, extending longitudinally of the axle. The axle can be configured to be fixed against rotation. The axle can e.g. be non-rotataby fixed to a frame of the bicycle. The transmission comprises a plurality of sun gears rotatably mounted around the axle. The transmission comprises a plurality of clutch mechanism for selectively preventing rotation of one or more of the plurality of sun gears in at least one rotational direction about the axle. The transmission comprises a camshaft mounted inside the axle for actuating the plurality of clutch mechanisms. The axle has a different outer radius at positions of different sun gears of the plurality of sun gears.

According to an aspect 1s provided a bicycle transmission comprising an axle. The axle can e.g. be a wheel axle. The transmission can be an internally geared hub transmission. The axle can e.g. be a shaft, such as a layshaft, in a crank transmission. The transmission can be a crank transmission unit. The axle has a central axis, extending longitudinally of the axle. The axle can be configured to be fixed against rotation. The axle can e.g. be non-rotataby fixed to a frame of the bicycle. The transmission comprises a plurality of sun gears rotatably mounted around the axle. The transmission comprises a plurality of clutch mechanism for selectively preventing rotation of one or more of the plurality of sun gears in at least one rotational direction about the axle. The transmission comprises a camshaft mounted inside the axle for actuating the plurality of clutch mechanisms. Each clutch mechanism comprises at least one pawl configured to be actuated by the camshaft, such that the at least one pawl is selectively in engagement or in disengagement with the respective sun gear. A first position of the at least one pawl of at least one of the clutch mechanisms is rotated about the central axis relative to a second position of the at least one pawl of at least another one of the clutch mechanisms. Hence, the clutch mechanism may be actuated by the camshaft which may comprise a single notch profile for actuating the plurality of clutch mechanisms. The singe notch profile can comprise a cam, or a plurality of cams, extending along an axial direction of the camshaft. The singe notch profile, e.g. the cam, or the plurality of cams, can extend along a line parallel to a central axial axis of the camshaft.

Optionally, each clutch mechanism is configured for in a first mode selectively preventing rotation of the respective sun gear in a first rotational direction about the axle, and in a second mode selectively preventing rotation of the respective sun gear in an opposite second rotational direction about the axle.

Optionally, for each clutch mechanism the at least one pawl comprises a first pawl and a second pawl configured to be actuated by the camshaft, such that the first pawl is selectively in engagement with the respective sun gear in the first mode, and the second pawl is selectively in engagement with the respective sun gear in the second mode.

According to an aspect is provided a bicycle transmission comprising an axle. The axle can e.g. be a wheel axle. The transmission can be an internally geared hub transmission. The axle can e.g. be a shaft, such as a layshaft, in a crank transmission. The transmission can be a crank transmission unit. The axle has a central axis, extending longitudinally of the axle. The axle can be configured to be fixed against rotation. The axle can e.g. be non-rotataby fixed to a frame of the bicycle. The transmission comprises a sun gear rotatably mounted around the axle. The transmission comprises a clutch mechanism for selectively preventing rotation the sun gears in at least one rotational direction about the axle. The transmission comprises a camshaft having a cam for actuating the clutch mechanism. The clutch mechanism comprises at least one pawl hingedly supported in a pocket of the axle, such that the cam can selectively radially pivot the at least one pawl in engagement with the sun gear for blocking rotation of the sun gear relative to the axle in a first rotational direction. The at least one pawl 1s tangentially movable in the pocket to allow the pawl the move tangentially and radially inwards relative to the cam to allow freewheeling of the sun gear in a second, opposite rotational direction. Thus, the at least one pawl can e.g. be pivoted radially outward such that the at least one pawl is in engagement with the sun gear for blocking rotation of the sun gear relative to the axle in the first rotational direction. The at least one pawl can e.g. be pivoted radially inward such that the at least one pawl is disengaged from the sun gear for allowing rotation of the sun gear relative to the axle in the first rotational direction. When the at least one pawl is pivoted, e.g. radially outwardly, in engagement with the sun gear for blocking rotation of the sun gear relative to the axle in the first rotational direction, rotation of the sun gear in the second rotational direction can tangentially move the at least one pawl in the second rotational direction, allowing the pawl to pivot, e.g. radially inwardly, out of engagement with the sun gear for allowing freewheeling of the sun gear in the second rotational direction.

Optionally, the transmission, e.g. the clutch mechanism, comprises a spring for biasing the at least one pawl radially inwards.

Optionally, the transmission, e.g. the clutch mechanism, comprises a spring for biasing the at least one pawl tangentially into the pocket, e.g. towards, such as against, a radial end wall of the pocket.

Optionally, the transmission, e.g. the clutch mechanism, comprises a spring having an arm extending around a radially outer surface of the at least one pawl for biasing the at least one pawl radially inwards.

According to an aspect 1s provided a bicycle transmission comprising an axle. The axle can e.g. be a wheel axle. The transmission can be an internally geared hub transmission. The axle can e.g. be a shaft, such as alayshaft, in a crank transmission. The transmission can be a crank transmission unit. The axle has a central axis, extending longitudinally of the axle. The axle can be configured to be fixed against rotation. The axle can e.g. be non-rotataby fixed to a frame of the bicycle. The transmission comprises a sun gear rotatably mounted around the axle. The transmission comprises a clutch mechanism for selectively preventing rotation the sun gears in at least one rotational direction about the axle. The transmission comprises a camshaft having a cam for actuating the clutch mechanism. The clutch mechanism comprises a first pawl and a second pawl, each hingedly supported in a respective first and second pocket of the axle, such that the cam can selectively radially pivot the first pawl in engagement with the sun gear for blocking rotation of the sun gear relative to the axle in a first rotational direction, or radially pivot the second pawl in engagement with the sun gear for blocking rotation of the sun gear relative to the axle in a second, opposite rotational direction. The first pawl is tangentially movable in the first pocket to allow the first pawl to move tangentially and move radially inwards relative to the cam to allow freewheeling of the sun gear in the second rotational direction, and wherein the second pawl is tangentially movable in the second pocket to allow the second pawl to move tangentially and move radially inwards relative to the cam to allow freewheeling of the sun gear in the first rotational direction.

Thus, in a first mode, the first pawl can e.g. be pivoted radially outward such that the first pawl is in engagement with the sun gear for blocking rotation of the sun gear relative to the axle in the first rotational direction.

The first pawl can e.g. be pivoted radially inward such that the first pawl is disengaged from the sun gear for allowing rotation of the sun gear relative to the axle in the first rotational direction.

In a second mode, the second pawl can e.g. be pivoted radially outward such that the second pawl is in engagement with the sun gear for blocking rotation of the sun gear relative to the axle in the second rotational direction.

The second pawl can e.g. be pivoted radially inward such that the second pawl is disengaged from the sun gear for allowing rotation of the sun gear relative to the axle in the second rotational direction.

In the first mode, when the first pawl is pivoted, e.g. radially outwardly, in engagement with the sun gear for blocking rotation of the sun gear relative to the axle in the first rotational direction, rotation of the sun gear in the second rotational direction can tangentially move the first pawl in the second rotational direction, allowing the first pawl to pivot, e.g. radially inwardly, out of engagement with the sun gear for allowing freewheeling of the sun gear in the second rotational direction.

In the second mode, when the second pawl is pivoted, e.g. radially outwardly, in engagement with the sun gear for blocking rotation of the sun gear relative to the axle in the second rotational direction, rotation of the sun gear in the first rotational direction can tangentially move the second pawl in the first rotational direction, allowing the second pawl to pivot, e.g. radially inwardly, out of engagement with the sun gear for allowing freewheeling of the sun gear in the first rotational direction.

Thus, the transmission allows for in the first mode blocking rotation of the sun gear in the first rotational direction, while allowing freewheeling of the sun gear in the second rotational direction, and in the second mode blocking rotation of the sun gear in the second rotational direction, while allowing freewheeling of the sun gear in the first rotational direction.

Optionally, the first and/or second pawl is L-shaped. The first and/or second pawl can have a first body portion extending substantially tangentially to an outer surface of the axle, and a second body portion extending substantially radially inwards from the first body portion. The first body portion may have a proximal end near a pivot axis of the pawl and a distal end having an engagement surface for engaging an engagement surface of the sun gear. The second body portion may be connected to the distal end of the pawl. The second body portion may carry one or more support surfaces as described above. The cam shaft can pivot the pawl radially outwardly by positioning the cam of the camshaft underneath the support surface(s). Tangential movement of the pawl can cause the support surface(s) to move off the cam, allowing the pawl to pivot radially inwards.

Optionally, the transmission comprises one or more springs for biasing the first and second pawl radially inwards.

Optionally, the transmission comprises one or more springs for biasing the first pawl tangentially into the first pocket and for biasing the second pawl tangentially into the second pocket.

Optionally, the transmission comprises a single spring for biasing the first and second pawl radially inwards, biasing the first pawl tangentially into the first pocket and biasing the second pawl tangentially into the second pocket.

Optionally, the transmission comprises a spring having a helically hound section, a first arm extending from a first end of the helically wound section, and a second arm extending from a second end of the helically wound section, wherein a distal end of the first arm is connected to the first pawl, and a distal end of the second arm is connected to the second pawl.

Optionally, the first and second arms together wrap around the axle over more than 360 degrees, such that the first arm pushes the second pawl radially inwards and the second arm pushes the first pawl radially inwards.

Optionally, the transmission comprising a plurality of sun gears.

For each of the above aspects, the following can apply.

Optionally, first pawl and the second pawl are separate bodies. The first pawl and the second pawl may be connected to each other, e.g. such that they move in unison. Optionally, first pawl and the second pawl are together formed by a single body. Hence, the first and second pawl may together form a monolithic part.

Optionally, the transmission comprises one or more bearings, such as roller bearings or plain bearings, forming a contact point between the camshaft and the respective pawl(s). Optionally, the pawl comprises one or more bearings for engaging a cam of the camshaft. Optionally, each pawl comprises two bearings, each bearing engaging a different cam section of the cam shaft. The bearings reduce friction between the camshaft and the respective pawl(s). This can enhance ease of actuating the pawl(s). This can e.g. reduce a torque needed to rotate the camshaft.

Optionally, the transmission comprises one or more bearings, such as roller bearings and/or plain bearings, mounted for supporting the camshaft inside the axle.

According to an aspect 1s provided a bicycle transmission comprising an axle. The axle can e.g. be a wheel axle. The transmission can be an internally geared hub transmission. The axle can e.g. be a shaft, such as a layshaft, in a crank transmission. The transmission can be a crank transmission unit. The axle has a central axis, extending longitudinally of the axle. The axle can be configured to be fixed against rotation. The axle can e.g. be non-rotataby fixed to a frame of the bicycle. The transmission comprises a sun gear rotatably mounted around the axle. The transmission comprises a clutch mechanism for selectively preventing rotation of the sun gear in at least one rotational direction about the axle. The transmission comprises a camshaft having a cam for actuating the clutch mechanism. The clutch mechanism comprises at least one pawl hingedly supported in a pocket of the axle, such that the cam can selectively radially pivot the at least one pawl in engagement with the sun gear for blocking rotation of the sun gear relative to the axle in a first rotational direction. The at least one pawl is tangentially movable in the pocket to allow the pawl the move tangentially and radially inwards relative to the cam to allow freewheeling of the sun gear in a second, opposite rotational direction. Thus, when the pawl is pivoted out of engagement with the sun gear, the sun gear can freely rotate, at least in the first rotational direction. When the pawl is pivoted into engagement with the sun gear, rotation of the sun gear in the first rotational direction is prevented, but freewheeling of the sun gear in the second rotational direction is possible.

Optionally, transmission comprises a spring having an arm extending around a radially outer surface of the at least one pawl for biasing the at least one pawl radially inwards.

Optionally, transmission comprises a spring for biasing the at least one pawl tangentially against a tangential end wall of the pocket.

According to an aspect 1s provided a bicycle transmission comprising an axle. The axle can e.g. be a wheel axle. The transmission can be an internally geared hub transmission. The axle can e.g. be a shaft, such as a layshaft, in a crank transmission. The transmission can be a crank transmission unit. The axle has a central axis, extending longitudinally of the axle. The axle can be configured to be fixed against rotation. The axle can e.g. be non-rotataby fixed to a frame of the bicycle. The transmission comprises a sun gear rotatably mounted around the axle. The transmission comprises a clutch mechanism for selectively preventing rotation of the sun gear in at least one rotational direction about the axle. The transmission comprises a camshaft having a cam for actuating the clutch mechanism. The clutch mechanism comprises a first pawl and a second pawl, each hingedly supported in a respective first and second pocket of the axle, such that the cam can selectively radially pivot the first pawl in engagement with the sun gear for blocking rotation of the sun gear relative to the axle in a first rotational direction, or radially pivot the second pawl in engagement with the sun gear for blocking rotation of the sun gear relative to the axle in a second, opposite rotational direction. The first pawl is tangentially movable in the first pocket to allow the first pawl to move tangentially and move radially inwards relative to the cam to allow freewheeling of the sun gear in the second rotational direction, and wherein the second pawl is tangentially movable in the second pocket to allow the second pawl to move tangentially and move radially inwards relative to the cam to allow freewheeling of the sun gear in the first rotational direction. Thus the transmission allows, in a first mode, selectively preventing rotation of the at least one sun gear in the first rotational direction about the axle, while allowing freewheeling in the second rotational direction, and, in a second mode, selectively preventing rotation of the at least one sun gear in the second rotational direction about the axle, while allowing freewheeling in the first rotational direction.

Optionally, tangential movement of the first or second pawl causes the pawl to move beyond the cam, such that radial inward pivoting of the pawl beyond the cam is enabled.

Optionally, the transmission comprises a plurality of sun gears, having associated.

According to an aspect 1s provided a bicycle transmission comprising an axle. The axle can e.g. be a wheel axle. The transmission can be an internally geared hub transmission. The axle can e.g. be a shaft, such as a layshaft, in a crank transmission. The transmission can be a crank transmission unit. The axle has a central axis, extending longitudinally of the axle. The axle can be configured to be fixed against rotation. The axle can e.g. be non-rotataby fixed to a frame of the bicycle. The transmission comprises at least one sun gear rotatably mounted around the axle. The transmission comprises at least one clutch mechanism for selectively preventing rotation of the at least one sun gear in at least one rotational direction about the axle. The transmission comprises a camshaft mounted inside the axle for actuating the at least one clutch mechanism. The transmission comprises one or more bearings mounted for supporting the camshaft inside the axle.

Optionally, the bearings are roller bearings or plain bearings.

For any of the above aspects, the following can apply.

Optionally, the camshaft comprises a plurality of cams along a longitudinal direction of the camshaft, each for engaging the pawl(s) associated with a consecutive sun gear of the plurality of sun gears, wherein the cams are mutually aligned along a single line that extends parallel to the central axis.

Optionally, the plurality of sun gears meshes with a stepped planet gear carried by a planet carrier. Optionally, each sun gear of the plurality of sun gears meshes with a planet gear part of a stepped planet gear carried by a planet carrier. Optionally, each planet gear part has a different radius.

Optionally, at least one planet gear part meshes with a ring gear.

Optionally, the transmission comprises a switching mechanism arranged for being adjustable between a first state for establishing a torque transmission from a transmission input to the ring gear and from the planet carrier to a transmission output, and a second state for establishing a torque transmission from the transmission input to the planet carrier and from the ring gear to the transmission output.

Optionally, the switching mechanism comprises a first actuatable clutch in a transmission path between the transmission input and the planet carrier, and a first freewheel in a transmission path between the transmission input and the ring gear; and a second actuatable clutch in a transmission path between the ring gear and the transmission output, and a second freewheel in a transmission path between the planet carrier and the transmission output.

Optionally, the camshaft is further configured for actuating the switching mechanism. Optionally, the camshaft comprises one or more grooves for actuating the switching mechanism. Optionally, the camshaft is configured for axially moving a selector from a first position to a second position or from the second position to the first position, wherein the first actuatable clutch and/or the second actuatable clutch is configured to switch from a coupled state to a decoupled state or from a decoupled state to a coupled state upon movement of the selector.

Optionally, the transmission comprises a driving mechanism for selectively moving one or more of the selectors from its first position to its second position, or from its second position to its first position.

Optionally, the driving mechanism is configured for driving intermediate bodies that are each individually resiliently connected to the selectors.

Optionally, the grooves of the camshaft are configured for driving a plurality of pins longitudinally of the camshaft, each pin being associated with one of the selectors or one of the intermediate bodies.

Optionally, the selector is arranged for selectively being in a gripping or non-gripping mode, the selector having a first portion of a first outer diameter and a second portion of a second outer diameter, wherein the first outer diameter is larger than the second outer diameter, wherein the selector is axially movable between the first position and the second position; wherein when the selector is in the first position the selector is in the gripping mode being arranged for allowing gripping at least one actuation member of the clutch or brake system; and wherein when the selector 1s in the second position the selector is in the non-gripping mode being arranged for not engaging the at least one actuation member.

According to an aspect 1s provided a bicycle transmission hub comprising the bicycle transmission of any of the above aspects.

According to an aspect 1s provided a bicycle crank transmission comprising the bicycle transmission of any of the above aspects.

According to an aspect 1s provided a bicycle comprising the bicycle transmission hub and/or the bicycle crank transmission.

It will be appreciated that any of the aspects, features and options described herein can be combined.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings in which:

Figure 1 shows an example of a transmission;

Figure 2 shows a schematic example of a transmission;

Figures 3A-3C show an example of an actuator;

Figures 4A-41 show an example of a sequence of gear shifting;

Figure 5A shows an example of a freewheel clutch;

Figure 5B shows an example of an actuatable bidirectional clutch mechanism;

Figures GA and 6B show examples of an actuatable clutch of a shifting mechanism;

Figures 7A and 7B show an example of an actuator;

Figure 8A shows an example of a spring;

Figure 8B shows an example of a clutch;

Figures 9A and 9B show an example of a selector;

Figures 10A and 10B show an example of a selector;

Figure 10C shows an example of a bush;

Figures 11A, 11B and 11C show an example of a selector; and

Figure 12 shows an example of a bicycle.

DETAILED DESCRIPTION

Figures 1 and 2 show schematic examples of a bicycle transmission 1000 for a human powered vehicle or light electric vehicle, such as bicycle.

In these examples, the transmission 1000 is embodied as a hub transmission but it will be appreciated that the transmission may also be embodied as a crank transmission. The transmission 1000 includes a transmission input I and a transmission output O. Here, the transmission input I is connected to a rear sprocket 3 for engaging a chain or belt of an chain or belt drive 300. The sprocket 3 may be part of a cassette of sprockets, such as including two or three sprockets. In a particular example, the cassette of sprockets includes at most two or at most 3 sprockets. In the embodiment of a crank transmission, the transmission input I may be connected to a crank of the bicycle. Here, the transmission output O is connected to a hub shell 51, which may in turn be connected to a driven wheel of the bicycle. In the embodiment of a crank transmission, the transmission output O may be connected to a front chain ring of the chain or belt drive 300.

The transmission 1000 comprises a transmission system 100, here a planetary gear set 100, arranged for providing a speed reduction and/or speed increase between the input I and the output O. The planetary gear set

100 comprises a ring gear 128 and a planet carrier 126 carrying one or more planet gears 127. The planet carrier 126 in this example carries one or more stepped planet gears 127 having multiple planet gear parts 1271 having different planet radii. In this example, the stepped planet gear has four planet gear parts 127a, 127b, 127c, 127d. The ring gear 128 meshes with one of the different planet radii 1271. Here, the ring gear 128 meshes with the third planet gear part 127c. The planetary gear set 100 also comprises a plurality of different sun gears 1291. The plurality of sun gears respectively mesh with the plurality of different planet radii 1271. Here, the plurality of sun gears comprises four sun gears 129a, 129b, 129c, 129d. Notice that in this example, the sun gears 1291 are positioned with ever increasing diameters from one end of the axle 30 to the other end of the axle. This can be beneficial in combination with an ever increasing axle 30 diameter corresponding to the increasing sun gear diameter as described below. The same applies to the planet gear parts 1271. It 15, however, also possible to position the sun gear 129d with the smallest diameter between two sun gears of larger diameter. This can provide a compact build. Similarly, positioning the planet gear parts 127d with the largest diameter between two planet gear parts of smaller diameter can provide a compact build.

The sun gears 1291 are rotatably arranged about a stationary axle 30. The stationary axle 30 may be mounted to a frame of the bicycle, for supporting torque thereon. Therefore, the axle may be mounted rotatably fixed to the frame.

The transmission 1000 comprises a switching mechanism. The switching mechanism comprises a first actuatable clutch mechanism S1 and a second actuatable clutch mechanism S2. the first actuatable clutch mechanism S1 is arranged in a transmission path between the transmission input I and the planet carrier 126. The second actuatable clutch mechanism

S2 1s arranged in a transmission path between the ring gear 128 and the transmission output O. The transmission 1000 also comprises a first freewheel 11 in a transmission path between the transmission input I and the ring gear 128. The first freewheel 11 is hence parallel to the first actuatable clutch mechanism S1. The transmission 1000 also comprises a second freewheel 12 in a transmission path between the planet carrier 126 and the transmission output O. The second freewheel 12 is hence parallel to the second actuatable clutch mechanism S2.

The first switching mechanism is configured for selectively being in a first state or a second state. In the first state, both the first and the second actuatable clutch mechanisms S1, S2 are in an unclutched state. Torque can accordingly be transmitted in the first state from the transmission input I via the first freewheel 11 to the ring gear 128 and from the planet carrier 127 via the second freewheel 12 to the transmission output O. In this state, the planetary gear set 100 provides a speed reduction from the ring gear 128 to the planet carrier 126 in accordance with the relative dimensions of the cooperating rotational members of the planetary gear set 100.

In the second state of the switching mechanism, both the first and the second actuatable clutch mechanisms S1, S2 are in a clutched state.

Torque can accordingly be transmitted in the second state from the transmission input I via the first actuatable clutch mechanism S1 to the planet carrier 126 and from the ring gear 128 via the second actuatable clutch mechanism S2 to the transmission output O. The first freewheel 11 and the second freewheel 12 are overrun in the second state. In the second state, the planetary gear set 100 provides a speed increase from the planet carrier 126 to the ring gear 128 in accordance with the relative dimensions of the cooperating rotational members of the planetary gear set 100.

Here, the transmission 1000 also comprises a third freewheel 13 arranged in series with the first actuatable clutch S1, and a fourth freewheel 14 arranged in series with the second actuatable clutch S2. The third and fourth freewheels 13 and 14 can prevent lockup of the transmission 1000 if the bicycle were to be rolled backwards.

The switching mechanism enables for reversing a transmission path through the planetary gear set 100, e.g. from ring gear 128 to carrier

126 or vice versa, to effectively increase the range of transmission ratios of the transmission 1000 as whole. In the first state of the switching mechanism, the transmission 1000 operates according to an underdrive transmission ratio, reducing the rotational speed from the input I to the output O. In the second state of the switching mechanism, the transmission 1000 operates according to an overdrive transmission ratio, increasing the rotational speed from the input I to the output O.

The switching mechanism may also be arranged for selectively being in a third state. In the third state, the first actuatable clutch mechanism S1 may be in its clutched state, while the second actuatable clutch mechanism S2 is in its unclutched state, or vice versa. In the third state, the transmission input I and the transmission output O are coupled to the same rotational member of the planetary gear set 100, e.g. both to the planet carrier 126 or both to the ring gear 128. In the third state, the transmission may be operable according to a unitary transmission ratio, e.g. a transmission ratio of 1:1.

The transmission 1000 further comprises a clutch mechanism. The clutch mechanism is arranged for selectively clutching a selective one of the plurality of sun gears 1291 to the stationary axle 30. Hereto, the clutch mechanism comprises a plurality of actuatable bidirectional clutch mechanisms Ci. In this example, the plurality of actuatable bidirectional clutch mechanisms Ci comprises four actuatable bidirectional clutch mechanisms C1, C2, C3, C4. Each actuatable bidirectional clutch mechanism Ci is associated with a respective sun gear 1291, for clutching the associated sun gear 129i to the stationary axle 30 in a selective one of two opposing rotation directions. Each actuatable bidirectional clutch mechanism Ci is arranged for being selectively in a first disposition or a second disposition. In the first disposition, the actuatable bidirectional clutch mechanism Ci prevents rotation of the respective sun gear 129i in the first rotation direction about the stationary axle 30. Herein, preventing rotation of the respective sun gear 129i in the first rotation direction about the stationary axle 30 is also referred to as braking the respective sun gear 1291 in the first rotation direction. In the second disposition, the actuatable bidirectional clutch mechanism C2.i prevents rotation of the respective sun gear 1291 in the second rotation direction about the stationary axle 30.

Herein, preventing rotation of the respective sun gear 1291 in the second rotation direction about the stationary axle 30 is also referred to as braking the respective sun gear 1291 in the second rotation direction. The direction in which a sun gear 1291 is to be braked is dependent on the state of the switching mechanism. For example, if the switching mechanism is in its first state, a selective one of the actuatable bidirectional clutch mechanisms

Ci may prevent rotation of a respective sun gear 129a in the second rotational direction, whereas if the switching mechanism is in its second state, a selective one of the actuatable bidirectional clutch mechanisms Ci may prevent rotation of a respective sun gear 129a in the first rotational direction.

When the transmission input I is driven in the first rotational direction R1 about the stationary axle 30, while the switching mechanism is in the first state, the ring gear 128 is also driven in the first rotational direction, and via the stepped planet gear 127, a rotational force is induced on the sun gears 1291 in the second, reverse, rotational direction. By braking a selective one of the sun gears 1291 in the second rotational direction with a corresponding one of the clutch mechanisms Ci, torque can be transmitted from the ring gear 128 to the planet carrier 126, according to an underdrive transmission ratio. When the transmission input I is driven in the first rotational direction about the stationary axle 30, while the switching mechanism 1s in the second state however, the planet carrier 126 is also driven in the first rotational direction, and via the stepped planet gear 127, a rotational force is induced on the sun gears 1291 in the first rotational direction. By braking a selective one of the sun gears 1291 in the first rotational direction with a corresponding one of the clutch mechanisms Ci,

torque can be transmitted from the planet carrier 126 to the ring gear 128 according to an overdrive transmission ratio.

In each of the first and second dispositions, the actuatable bidirectional clutch mechanisms Ci may be arranged to prevent rotation of the sun gear 129 in one direction, while allowing rotation of the sun gear in the opposite rotation direction, e.g. by freewheeling. Hence, in the first disposition, the actuatable bidirectional clutch mechanism Ci may be configured for allowing freewheeling of the sun gear 1291 in the second rotational direction while preventing rotation of that sun gear 129i in the first rotational direction. Also, in the second disposition, the actuatable bidirectional clutch mechanism Ci may be configured for allowing freewheeling of the sun gear 1291 in the first rotational direction while preventing rotation of that sun gear 1291 in the second rotational direction.

One or more of the actuatable bidirectional clutch mechanisms Ci may also selectively be adjusted to a third disposition. In the third disposition, the actuatable bidirectional clutch mechanism Ci may allow free rotation of the respective sun gear 129i in both rotational directions about the stationary axle 30. For instance, while one of the actuatable bidirectional clutch mechanisms Ci is in the first disposition or the second disposition, other ones of the actuatable bidirectional clutch mechanisms can be in the third disposition.

One or more, e.g. all, of the actuatable bidirectional clutch mechanisms Ci may be configured to be adjustable to be in the third disposition, if the switching mechanism is in its third state, for allowing the ring gear 128 and the planet carrier 126 to corotate about the stationary axle 30. This way, the transmission 1000 may provide a unitary transmission ratio between the input I and output O. If the switching mechanism is in its third state, one or more of the actuatable bidirectional clutch mechanisms Ci may also be adjusted to be in the second disposition, for allowing the ring gear 128 and the planet carrier 126 to corotate about the stationary axle 30 in the first rotational direction.

It is possible that one (or more) of the actuatable bidirectional clutch mechanisms Ci is a biased actuatable bidirectional clutch mechanism configured to be in the second disposition by default and configured to be actively actuated to the first disposition. The biased actuatable bidirectional clutch mechanism may be configured not to have a third disposition. The biased actuatable bidirectional clutch mechanism can be used to prevent that all actuatable bidirectional clutch mechanisms are in the third disposition while the switching mechanism is in the first or second state, which could lead to a state in which no torque is transferred by the transmission. It is also possible that one (or more) of the actuatable bidirectional clutch mechanisms Ci is a biased actuatable bidirectional clutch mechanism configured to be in the first disposition by default and configured to be actively actuated to the second disposition.

In figures 1 and 2 the planetary gear set 100 comprises four sun gears 129a, 129b, 129c, 129d meshing with four respective planet radii 127a, 127b, 127c, 127d of the stepped planet gear 127. Also, the plurality of clutch mechanisms Ci comprises four actuatable bidirectional clutch mechanisms

C1, C2, C3, C4, arranged for selectively clutching the respective sun gears 129a, 129h, 129c, 129d to the stationary axle 30. An eight speed or nine- speed transmission 1000 can be hence be obtained. Exemplary clutch states of the switching mechanism (first actuatable clutch mechanism S1 and a second actuatable clutch mechanism S2) and clutch mechanism (actuatable bidirectional clutch mechanisms C1, C2, C3, C4) for the nine-speed transmission 1000 are summarized in table 1. (disposition) | (disposition) | (disposition) | (disposition) freeweel

TH rie

Exemplary clutch states of the switching mechanism (first actuatable clutch mechanism S1 and a second actuatable clutch mechanism

S2) and clutch mechanism (actuatable bidirectional clutch mechanisms C1, (C2, C3, C4) for the nine-speed transmission 1000 are summarized in table 2 for a situation in which the first actuatable bidirectional clutch mechanism

C1 is a biased actuatable bidirectional clutch mechanism.

Table 2

Ti 7 7 er

In tables 1 and 2, the transmission 1000 is operable according to a unitary transmission ratio, but this gear may optionally be omitted. The shifting mechanism may for example not include the third state, but may be adjusted only between the first state and the second state. Without the unitary gear, the first actuatable clutch S1 and the second actuatable clutch

S2 can be actuated in synchrony with each other, switching both clutches

S1, S2 simultaneously between their clutched and their unclutched state.

This may simplify the actuation construction. A benefit of the unitary gear 1s an increase in transmission ratio range. Also, with the unitary gear, each upshift or downshift to a next higher or lower gear may involve only shifting one the first and second actuatable clutch mechanisms S1, S2.

In tables 1 and 2, the actuatable bidirectional clutch mechanisms also include the optional third disposition. Instead, the actuatable bidirectional clutch mechanisms Ci may be adjusted between only the first disposition and the second disposition.???

Without the clutches S1 and S2 we can use only gear 1 to 4 or only use 5 to 9 with gear 5 being on a freewheel.

Without the clutches C1 to C4 it is a 3-speed transmission

In the example of figure 1 and 2, the axle 30 has a central axis A.

The axle 30 can e.g. be a wheel axle or a layshaft in a crank transmission.

An actuator for actuating the clutch mechanisms C1, C2, C3, C4 is mounted inside the axle 30. In this example, the actuator is an electromechanical actuator. The electromechanical actuator comprises an electric motor 32 in this example. The actuator in this example comprises a camshaft 34 mounted inside the axle 30 for actuating the clutch mechanisms C1, C2, C3,

C4. The electromechanical actuator 32 is configured for rotating the camshaft 34 inside the axis 30.

Figure 3A shows an example of the actuator. In figure 3A the electromechanical actuator 32 and the camshaft 34 are visible. Here, the camshaft comprises a plurality of cams Ni, in particular, six cams N1, N2,

N3, N4, N5, N6. Here, the camshaft 34 comprises a single notch profile for actuating the plurality of clutch mechanisms. The singe notch profile is formed by the plurality of cams Ni, extending along an axial direction of the camshaft 34. In this example, the singe notch profile, e.g. the plurality of cams Ni, extends along a line parallel to a central axial axis A of the camshaft 34.

Figure 3B shows the actuator of figure 3A with pawls Pi, in particular pawls P1, P2A, P2B, P3A, P3B, P4A, P4B, shown. Each clutch mechanism C1, C2, C3, C4 comprises one or more pawls Pi configured to be actuated by the camshaft 34. In this example, the second C2, third C3 and fourth C4 clutch mechanisms each comprise a first pawl PiA and a second pawl PiB configured to be actuated by the camshaft 34, such that the first pawl PiA is selectively in engagement with the respective sun gear 1291 in the first mode, and the second pawl PiB is selectively in engagement with the respective sun gear 1291 in the second mode.

Each pawl Pi in this example comprises two support surfaces Pis that are supported on the camshaft 34 and can be lifted by the cams Ni.

Here, the support surfaces Pis are formed as bearings, such as roller bearings or plain bearings. In this example, the first pawl P1 of the first clutch mechanism C1 comprises two support surfaces, here two roller bearings, Pls. The support surfaces P1s are supported on the camshaft 34 and lifted by the cams N1 and N2. A circumferential groove is here provided in the camshaft 34 between the cams N1 and N2 as clearance for the first pawl P1. In this example, the first and second pawls P2A, P2B of the second clutch mechanism C2 each comprise two support surfaces, here two roller bearings, P2As, P2Bs. The support surfaces P2As, P2Bs are supported on the camshaft 34 and lifted by the cams N2 and N3. A circumferential groove is here provided in the camshaft 34 between the cams N2 and N3 as clearance for the first and second pawls P2A, P2B. In this example, the first and second pawls P3A, P3B of the third clutch mechanism C3 each comprise two support surfaces, here two roller bearings, P3As, P3Bs. The support surfaces P3As, P3Bs are supported on the camshaft 34 and lifted by the cams N3 and N4. A circumferential groove is here provided in the camshaft 34 between the cams N3 and N4 as clearance for the first and second pawls

P3A, P3B. In this example, the first and second pawls P4A, P4B of the fourth clutch mechanism C4 each comprise two support surfaces, here two roller bearings, P4As, P4Bs. The support surfaces P4As, P4Bs are supported on the camshaft 34 and lifted by the cams N5 and N6. A circumferential groove is here provided in the camshaft 34 between the cams N5 and N6 as clearance for the first and second pawls P4A, P4B.

It will be appreciated that it is also possible that the cams of the camshaft 34 are provided with bearings, such as roller bearings or plain bearings for contacting the pawls. In an example, the actuator comprises a rotation sensor and/or a position sensor. Thus, a gear in which the actuator is positioned can be monitored. It is for instance possible to monitor a rotational position of the electromechanical actuator 32 and/or the camshaft 34.

Figure 7B show an example in which two sun gears 1294, 129b are shown mounted on the axle 30 over the respective pawls P1, P2A, P2B. For clarity, the sun gears 129c, 129d are not shown in figure 7B.

As can be seen in more detail in figures 4A-4H, the pawls associated with larger sun gears in this example also have larger roller bearings for support surfaces, than pawls associated with smaller sun gears.

In this example, in each clutch mechanism C1, C2, C3, C4, the first

P1, P2A, P3A, P4A and second P2B, P3B, P4B pawls are configured for each pivoting about a respective pivot axis. In this example, each pawl comprises two protrusions Pip forming end of a pivot axle P of the respective pawl. The protrusions P2Bp of the second pawl P2B of the second clutch mechanism

C2 are indicated in figure 3B. It will be appreciated that the other pawls have similar protrusions in this example.

As can be seen in figure 3B, the pawls of the clutch mechanisms

C1, C2, C3, C4 are positioned rotated about the central axis A. That is, the pawl P1 of the first clutch mechanism C1 is positioned rotated about the central axis A relative to the pawls of the second, third and fourth clutch mechanisms C2, C3, C4. The first and second pawls P2A, P2B of the second clutch mechanism C2 are positioned rotated about the central axis A relative to the pawls of the first, third and fourth clutch mechanisms C1, C3,

C4. The first and second pawls P3A, P3B of the third clutch mechanism C3 are positioned rotated about the central axis A relative to the pawls of the first, second and fourth clutch mechanisms C1, C2, C4. The first and second pawls P4A, P4B of the fourth clutch mechanism C4 are positioned rotated about the central axis A relative to the pawls of the first, second and third clutch mechanisms C1, C2, C3. Thus, a first position of at least one pawl of at least one of the clutch mechanisms is rotated about the central axis relative to a second position of at least one pawl of at least another one of the clutch mechanisms. Here, a first position of the first and second pawls of at least one of the clutch mechanisms is rotated about the central axis relative to a second position of the first and second pawls of at least another one of the clutch mechanisms. As will be discussed in view of figures 4A-4H, in an example the pawls are positioned such that a rotation of the cam shaft in a single direction successively actuates the respective pawls such that the transmission ratios of the transmission are sequentially selected in a ascending or descending order. In this example, the positions of the pawls are spaced 40 degrees apart. Hence, the camshaft can be rotated over eight times 40 degrees to access nine different transmission ratios.

Figure 3B further shows two bearings 36, here roller bearings (but plains bearings are also possible) around the camshaft 34, for supporting the camshaft 34 inside the axle 30.

Figure 3C shows the actuator of figures 3A and 3B inside the axle 30. As shown in figure 3C, in this example the axle 30 has a plurality of axle sections of different outer diameter. In this example a first axle section 30A has a first outer diameter. The first 129a and second 129b sun gears can be mounted on the first axle section 30A in this example. A second axle section 30B has a smaller outer diameter than the first axle section 30A. The third sun gear 129c can be mounted on the second axle section 30B in this example. A third axle section 30C has a smaller outer diameter than the second axle section 30B. The fourth sun gear 129d can be mounted on the third axle section 30C in this example. Thus, the axle 30 has a different outer radius at positions of different sun gears 1291 of the plurality of sun gears. The different outer diameters of the axle sections 30A, 30B, 30C can provide ease of assembly of the clutch mechanisms C1, C2, C3, C4. The different outer diameters of the axle sections 304A, 30B, 30C can provide that a larger diameter axle section is provided supporting sun gears that transfer higher torque to the axle 30. Preferable, torque is supported from the axle 30 onto the frame of the bicycle on the side of the axle 30 having the larges axle section diameter, i.e. here the non drive side.

It can also be seen in figure 3C that a radial distance between a pivot axis p of the pawls and the central axis A of the axle 30 is different for different clutch mechanisms C1, C2, C3, C4 of the plurality of clutch mechanisms. For all the pawls Pi, the pivot axis p of the respective pawls Pi is positioned such that the pivot axle P is positioned just below the surface of the respective axle section. In this example, a first radial distance between the pivot axis p of the first pawl P1 of the first clutch mechanism

C1 and the central axis A of the axle 30 is equal to a second radial distance between the pivot axis p of the first and second pawls P2A, P2B of the second clutch mechanism C2 and the central axis A of the axle 30. In this example, the first radial distance between the pivot axis p of the first and second pawls P2A, P2B of the second clutch mechanism C2 and the central axis A of the axle 30 is larger than a third radial distance between the pivot axis p of the first and second pawls P3A, P3B of the third clutch mechanism

C3 and the central axis A of the axle 30. In this example, the third radial distance between the pivot axis p of the first and second pawls P3A, P3B of the third clutch mechanism C3 and the central axis A of the axle 30 is larger than a fourth radial distance between the pivot axis p of the first and second pawls P4A, P4B of the fourth clutch mechanism C4 and the central axis A of the axle 30. It will be appreciated that in this example, a radial distance between the tops of the cams N5, N6 of the fourth clutch mechanism C4 and the central axis A is also smaller than a radial distance between the tops of the cams N1, N2, N3, N4 of the first, second, and third clutch mechanism

C1, C2, C3 and the central axis.

The pivot axis p of the pawls is maintained at the radial distance from the central axis A in a pocket fashioned in the axle 30. In particular,

the protrusions Pip forming ends of the pivot axle P of the respective pawl are nested in pockets fashioned in the axle 30.

Figures 4A-4H show a sequence of gear shifting using the transmission of figures 1-3C. In this example, When the transmission input lis driven in the first rotational direction R1 about the stationary axle 30, while the switching mechanism is in the first state, the ring gear 128 is also driven in the first rotational direction, and via the stepped planet gear 127, a rotational force is induced on the sun gears 1291 in the second, reverse, rotational direction. By braking a selective one of the sun gears 1291 in the second rotational direction with a corresponding one of the clutch mechanisms Ci, torque can be transmitted from the ring gear 128 to the planet carrier 126, according to an underdrive transmission ratio.

Figure 4A shows a situation with the transmission input I driven in the first rotational direction R1 about the stationary axle 30, while the switching mechanism is in the first state. The first actuatable bidirectional clutch mechanism C1 is shown in the second disposition in figure 4A. The first actuatable bidirectional clutch mechanism C1, in this example, is a biased actuatable bidirectional clutch mechanism having only a single pawl

P1. The pawl P1 is not actuated by the cam N1, N2 in the first position. The biased actuatable bidirectional clutch mechanism C1 includes a freewheel clutch 15 allowing rotation in the first rotational direction R1, and blocking rotation in the second rotational direction R2. Figure 5A shows an example of the freewheel clutch 15 of the biased actuatable bidirectional clutch mechanism C1. Here, the freewheel clutch 15 comprises a plurality of rollers 151, such as balls or cylinders, between an inner race 151 and an outer race 150. In this example, the outer race 150 is provided with a sawtooth profile.

Hence, the largest sun gear 129a is braked, and torque is transmitted from the input I via the ring gear 128 to the planet gear 127 to the output O via the planet carrier 126. The transmission ratio is determined by the first sun gear 129a and the first planet gear part 127a, and constitutes that smallest transmission ratio (first gear, underdrive).

Figure 4B shows a situation with the transmission input I driven in the first rotational direction R1 about the stationary axle 30, while the switching mechanism is in the first state. The second actuatable bidirectional clutch mechanism C2 is shown in the second disposition in figure 4B. The camshaft has been rotated to a second position. The second pawl P2B 1s actuated by the cam N2, N3 in the second position. An engagement surface of the second pawl P2B engages a corresponding engagement surface associated with the second sun gear 129b, and blocks rotation in the second rotational direction R2. Hence, the second sun gear 129b is braked, and torque is transmitted from the input I via the ring gear 128 to the planet gear 127 to the output O via the planet carrier 126. The transmission ratio is determined by the second sun gear 129b and the second planet gear part 127b, and constitutes a next higher transmission ratio (second gear, underdrive).

Figure 4C shows a situation with the transmission input I driven in the first rotational direction R1 about the stationary axle 30, while the switching mechanism is in the first state. The third actuatable bidirectional clutch mechanism C3 is shown in the second disposition in figure 4C. The camshaft has been rotated to a third position. The second pawl P3B is actuated by the cam N3, N4 in the third position. An engagement surface of the second pawl P2B engages a corresponding engagement surface associated with the third sun gear 129c, and blocks rotation in the second rotational direction R2. Hence, the third sun gear 129c is braked, and torque is transmitted from the input I via the ring gear 128 to the planet gear 127 to the output O via the planet carrier 126. The transmission ratio 1s determined by the third sun gear 129c and the third planet gear part 127c, and constitutes a next higher transmission ratio (third gear, underdrive).

Figure 4D shows a situation with the transmission input I driven in the first rotational direction R1 about the stationary axle 30, while the switching mechanism is in the first state. The fourth actuatable bidirectional clutch mechanism C4 is shown in the second disposition in figure 4D. The camshaft has been rotated to a fourth position. The second pawl P4B is actuated by the cam N35, N6 in the fourth position. An engagement surface of the second pawl P4B engages a corresponding engagement surface associated with the fourth sun gear 129d, and blocks rotation in the second rotational direction R2. Hence, the fourth sun gear 129d is braked, and torque 1s transmitted from the input I via the ring gear 128 to the planet gear 127 to the output O via the planet carrier 126. The transmission ratio is determined by the fourth sun gear 129d and the fourth planet gear part 127d, and constitutes a next higher transmission ratio (fourth gear, underdrive).

Figure 4E shows a situation with the camshaft 34 rotated to a fifth position. In this fifth position, the fourth actuatable bidirectional clutch mechanism C4 is in the third disposition. Thus, neither the first pawl P4A nor the second pawl P4B is lifted by the cams N5, N6. In this situation, the switching mechanism is switched to the third state. Thus, the ring gear 128 and the planet carrier 126 are coupled to corotate. Torque is transmitted from the input I to the output O via the ring gear and/or planet carrier 126.

It will be appreciated that in this example the cams N5, N6 of the fourth clutch mechanism C4 is wider than the cams N1-N4 of the other clutch mechanisms C1, C2, C3. Hence, a smooth handover from the fourth to the fifth gear (and from the fifth to the sixth gear) can be obtained. This situation constitutes a next higher transmission ratio, which corresponds to a unity transmission ratio (fifth gear, unity transmission ratio).

Next, the switching mechanism is switched to the second state.

When the transmission input I is driven in the first rotational direction about the stationary axle 30, while the switching mechanism is in the second state, the planet carrier 126 is also driven in the first rotational direction, and via the stepped planet gear 127, a rotational force is induced on the sun gears 129i in the first rotational direction. By braking a selective one of the sun gears 1291 in the first rotational direction with a corresponding one of the clutch mechanisms Ci, torque can be transmitted from the planet carrier 126 to the ring gear 128 according to an overdrive transmission ratio.

Figure 4F shows a situation with the transmission input I driven in the first rotational direction R1 about the stationary axle 30, while the switching mechanism is in the second state. The fourth actuatable bidirectional clutch mechanism C4 is shown in the first disposition in figure 4F. The camshaft has been rotated to a sixth position. The first pawl P4A is actuated by the cam N5, N6 in the sixth position. An engagement surface of the first pawl P4A engages a corresponding engagement surface associated with the fourth sun gear 129d, and blocks rotation in the first rotational direction R1. Hence, the fourth sun gear 129d is braked, and torque is transmitted from the input I via the planet carrier 126 to the planet gear 127 and to the output O via the ring gear 128. The transmission ratio is determined by the fourth sun gear 129d and the fourth planet gear part 127d, and constitutes a next higher transmission ratio (sixth gear, overdrive).

Figure 4G shows a situation with the transmission input I driven in the first rotational direction R1 about the stationary axle 30, while the switching mechanism is in the second state. The third actuatable bidirectional clutch mechanism C3 is shown in the first disposition in figure 4F. The camshaft has been rotated to a seventh position. The first pawl P3A is actuated by the cam N3, N4 in the seventh position. An engagement surface of the first pawl P3A engages a corresponding engagement surface associated with the third sun gear 129c, and blocks rotation in the first rotational direction R1. Hence, the third sun gear 129c is braked, and torque is transmitted from the input I via the planet carrier 126 to the planet gear 127 and to the output O via the ring gear 128. The transmission ratio is determined by the third sun gear 129c and the third planet gear part 127c, and constitutes a next higher transmission ratio (seventh gear, overdrive).

Figure 4H shows a situation with the transmission input I driven in the first rotational direction R1 about the stationary axle 30, while the switching mechanism is in the second state. The second actuatable bidirectional clutch mechanism C2 is shown in the first disposition in figure 4G. The camshaft has been rotated to an eighth position. The first pawl P2A is actuated by the cam N2, N3 in the eighth position. An engagement surface of the first pawl P2A engages a corresponding engagement surface associated with the second sun gear 129b, and blocks rotation in the first rotational direction R1. Hence, the second sun gear 129b is braked, and torque is transmitted from the input I via the planet carrier 126 to the planet gear 127 and to the output O via the ring gear 128. The transmission ratio is determined by the second sun gear 129b and the second planet gear part 127b, and constitutes a next higher transmission ratio (eighth gear, overdrive).

Figure 41 shows a situation with the transmission input I driven in the first rotational direction R1 about the stationary axle 30, while the switching mechanism is in the second state. The first actuatable bidirectional clutch mechanism C1 is shown in the first disposition in figure 4H. The camshaft has been rotated to a ninth position. The pawl P1 is actuated by the cam N1, N2 in the ninth position. An engagement surface 38 of the pawl P1 engages a corresponding engagement surface 40 associated with the first sun gear 129a, and blocks rotation in the first rotational direction R1. Hence, the first sun gear 129a is braked, and torque is transmitted from the input I via the planet carrier 126 to the planet gear 127 and to the output O via the ring gear 128. The transmission ratio 1s determined by the first sun gear 129a and the first planet gear part 127a, and constitutes a next higher transmission ratio (ninth gear, overdrive).

It will be appreciated that while switching through the consecutive gears from the lowest (here first) gear to the highest (here ninth) gear, the sun gears 129i are first used in a sequence from the largest to the smallest sun gear, and subsequently in a sequence from the smallest to the largest sun gear.

Figure 5B shows an example of a sun gear 1291 with an actuatable bidirectional clutch mechanism Ci. The pawls PiA, PiB are in this example generally L-shaped. The pawls PiA, PiB have a first body portion 44 extending from the pivot axle P to the engagement surface 38. The first body portion extends substantially tangentially to the outer surface of the axle 30. The pivot axle P is hingedly supported in a pocket 48 of the axle 30. The pawls PiA, PiB have a second body portion 46 extending substantially radially inwards. The second body portion 46 carries the support surfaces

Pis. Here, the second body portion has two axially oriented bosses onto which roller bearings forming the support surfaces Pis are mounted. In this example, the engagement surface 38 of the pawls Pi and the corresponding engament surface 40 of the sun gear 129i are angled relative to the radial direction. The angle is chosen such that moving the engagement surfaces 38, 40 against and towards each other tends to move the pawl Pi radially inwards. Hence, the pawls Pi are biased to disengage. A spring may be added for spring biased disengagement of the pawls Pi. Figure 7A shows an example of the pawls Pi biased by a spring 121. Hence, the actuatable bidirectional clutch mechanism Ci is biased to disengage. In the first and second disposition, the presence of the cam Ni underneath the support surfaces Pis prevents the engagement surfaces 38, 40 from disengaging when pressed against each other. In figure 5B, the camshaft 34 is positioned such that the clutch mechanism Ci is in the first disposition. In this first disposition, rotating the sun gear 1291 in the first rotational direction R1 will force the engagement surfaces against each other, the first pawl PiA is pushed in the pocket 48 against a radial end wall 49 of the pocket 48, and rotation of the sun gear 129i in the first rotational direction is prevented (see corresponding figure 4G). Figure 5B shows the particular situation in which the clutch mechanism Ci is in the first disposition and the sun gear 1291 is driven in the second rotational direction R2. The actuatable bidirectional clutch mechanism Ci is configured such that, in the first disposition, the sun gear 1291 is prevented from rotating in the first rotational direction R1, but enabled to rotate (freewheel) in the second rotational direction R2. In that case, the protrusions 50 on the inner perimeter of the sun gear 1291 will push the first pawl PiA in the first rotational direction, tangentially moving the pawl PiA inside the pocket 48, away from the radial end wall 49 of the pocket, such that the support surfaces Pis drop off the cam Ni. This causes the first pawl PiA to pivot radially inward, such that the engagement surface 38 of the pawl PiA is at a radius that is smaller than the engagement surface 40 of the sun gear 129i.

As a result, the sun gear 129i can freewheel in the first rotational direction

R1 while the clutch mechanism Ci is in the first disposition. In this example, the first pawl PiA has a protrusion 52, such as a ridge, on a radially outward surface of the pawl PiA. The protrusion 52 can be caught by the protrusion 50 of the sun gear 1291 to promote moving the pawl PiA tangentially so as to drop off the cam Ni. In this example, a spring or other resilient element 15 provided to bias the pawl PiA back into the pocket 48.

The spring or other resilient element can pull the pawl, such that the pivot axle P tangentially abuts against the radial end wall of the pocket 48. It will be appreciated that similarly, the actuatable bidirectional clutch mechanism

Ci is configured such that, in the second disposition, the sun gear 129i is prevented from rotating in the second rotational direction R2, but enabled to rotate (freewheel) in the first rotational direction R1.

Figure 8A shows an example in which the spring 121 has the combined function of biasing the pawls PiA, PiB into the pocket 48, and for biasing the pawls PiA, PiB radially inward for biasing disengagement of the engagement surfaces 38, 40. In this example, the spring 121 comprises a helically wound section 121a. Two arms 121b, 121c extend from the ends of the helically wound section. The distal ends of the arms 121b, 121c overlap in this example. Thereby, the spring 121 wraps around the axle 30 over more than 360 degrees. The distal ends of the arms 121b, 121c are each provided with a hook 121d, 121e. In this example, the spring comprises a single helically wound section 121a. It will be appreciated that the spring may also comprise more than one, e.g. two, helically wound sections. As shown in figure 8B, the hooks 121d, 121e engage the respective pawls PiA,

PiB. Thus, pulling force of the spring 121 biases the pawls PiA, PiB such that the pivot axle P tangentially abuts against a radial end wall of the pocket 48. Also, the arms 121b, 121c of the spring are positioned in circumferential grooves Pig of the pawls PiA, PiB (see e.g. grooves Plg, P2g,

P3g, P4g in figures 7A and 7B), such that pulling force of the spring 121 biases the pawls PiA, PiB radially inward. Here, the arms wrap around the pawls PiA, PiB. In this example, the first arm 121b pushes the second pawl

PiB radially inwards, and the second arm 121c pushes the first pawl PiA radially inwards. Here, the arms are also positioned in a circumferential groove 30g in the outer surface of the axle 30. In this example, the spring 121 extends between the pawls PiA, PiB, i.e. a first end 121d of the spring is attached to a first pawl PiA, and a second end 121e of the spring is attached to a second pawl PiB. Hence, here the spring 121 pulls the pawls PiA, PiB towards each other. It will be appreciated that it is also possible that each pawl has one or more individual springs associated therewith.

Returning to Figures 1, 2 and 3A, the camshaft 34 is further configured for actuating the switching mechanism. In this example, the camshaft comprises one or more grooves 54, here two grooves, for actuating the switching mechanism. The camshaft 34 is configured for axially moving a selector 56 from a first position to a second position or from the second position to the first position. Here, the selector 56 comprises a pen 58 that extends into the groove 54. It will be appreciated that the groove 54 is shaped such that rotation of the camshaft 34 will axially move the pen 58, and thereby the selector 56. The first actuatable clutch S1 and/or the second actuatable clutch S2 is configured to switch from a coupled state to a decoupled state or from a decoupled state to a coupled state upon axial movement of the selector 56. In this example, the groves 54 are shaped such that the first actuatable clutch S1 and the second actuatable clutch S2 from the coupled state to the decoupled state or from the decoupled state to the coupled state substantially simultaneously.

The actuatable clutches S1, S2 of the shifting mechanism can be similar or identical to a clutch as described in WO2018/199757A2,

WO0O2020/085911A2, WO2021/080431A1 or WO2021/249945A1, incorporated herein by reference in their entirety. Referring to figures 6A and 6B, the actuatable clutches S1, S2 can have a first rotatable unit 80 including at least one first abutment surface 82 and a second rotatable unit 84 including at least one second abutment surface 86 arranged for selectively engaging the first abutment surface. The first and second abutment surfaces 82, 86 are adapted to each other so as to allow disengaging under load, preferably in two directions. The actuatable clutches S1, S2 can have a third rotatable unit 88 including at least one retaining member 90. The third rotatable unit 88 is arranged for selectively being in a first mode (figure 6A) or a second mode (figure 6B) relative to the second rotatable unit 84. In the first mode, the at least one retaining member 90 locks the at least one second abutment surface 86 for rotationally coupling the second rotatable unit 84 to the first rotatable unit 80, e.g. in two rotational directions. In the second mode, the at least one retaining member 90 releases the at least one second abutment surface 86 for decoupling the second rotatable unit 84 from the first rotatable unit 80. The actuatable clutches can include an actuator for moving the third rotatable unit from a first position (figure 6A) to a second position (figure 6B) or from a second position to a first position relative to the second rotatable unit. Here, the second rotatable unit 84 carries gripping members 92. The gripping members have the second abutment surface 86. The gripping members 92 are pivotally connected to the second rotatable unit 84. In the first position, here, the retaining member 90 is positioned such as to push the second abutment surfaces 86 of the gripping members 92 radially outwards into engagement with the first engagement surfaces 82. In this example, the second engagement surface 86 and the corresponding first engagement surface 82 are angled relative to the radial direction. The angle is chosen such that moving the engagement surfaces 82, 86 against and towards each other tends to move the gripping member 92 radially inwards. Hence, the gripping members 92 are biased to disengage.

A spring may be added for spring biased disengagement of the gripping member 92. Hence, the actuatable clutches S1, S2 are biased to disengage.

In the first position, the presence of the retaining member underneath the gripping member 92 prevents the engagement surfaces 82, 86 from disengaging when pressed against each other. In the second position, the retaining member 90 is positioned such as to allow the gripping member 92 to pivot radially inwards, to allow disengagement of the second abutment surface 86 from the first engagement surface 82.

The third rotatable unit 88 includes at least one actuation member 94 arranged for moving the third rotatable unit 88 from a first position to a second position or from a second position to a first position relative to the second rotatable unit 84. In this example, the actuatable clutches S1, S2 further includes a fourth unit 96 including a selector 98. The fourth unit 96 can be non-rotatable, e.g. relative to the axle 30. The selector being arranged for selectively being in a gripping or non-gripping mode. The selector 98 in the gripping mode is arranged for gripping the at least one actuation member 94 for rotating the third rotatable unit 88 from the first position to the second position or from the second position to the first position relative to the second rotatable unit 84. The selector 98 in the non- gripping mode is arranged for not engaging the at least one actuation member 94.

Figures 9A and 9B show an example of the selector 98. In this example, the selector includes one or more grooves 120 immobile relative to the axle 30. The selector further includes a selection bush 122 that is axially movable relative to the axle 30. The bush 122 comprises a first section 122A of a first outer diameter, and a second section 122B having a second outer diameter that is smaller than the first outer diameter. In this example, the bush 122 can be axially moved by a pin 124 riding in the groove 54 of the camshaft 34. The bush 122 can be moved into a first position (figure 9A) and a second position (figure 9B). As can be seen in figures 9A and 9B, in this example the two actuation members 94A and 94B are slightly different. In particular, a cutout 126A, 126B of the respective actuation members 94A, 94B is positioned differently.

With the bush in the first position, as shown in figure 9A, the first actuation member 94A rides with its radially inward end on the larger outer diameter first section 122A of the bush. Hence, the first actuation member 94A is prevented from entering the groove 120. With the bush in the first position, as shown in figure 8A, the second actuation member 94B has its cutout 126B aligned with the larger outer diameter first section 122A of the bush. Hence, the second actuation member 94A is enabled to enter the groove 120. With the bush in the second position, as shown in figure 9B, the second actuation member 94B rides with its radially inward end on the larger outer diameter first section 122A of the bush. Hence, the second actuation member 94B is prevented from entering the groove 120. With the bush in the second position, as shown in figure 9B, the first actuation member 94A has its cutout 126A aligned with the larger outer diameter first section 122A of the bush. Hence, the first actuation member 94A is enabled to enter the groove 120. Once the first or second actuation member 94A, 94B enters the groove 120, the third rotatable unit 88 is temporarily halted, causing the third rotatable unit to rotate relative to the second rotatable unit 84. The third rotatable unit 88 will rotate relative to the second rotatable unit 84 from a first position (figure 6A) to a second position (figure

GB) or from a second position to a first position. Hence, the actuatable clutch

S1, S2 will engage or disengage. After the third rotatable unit 88 moving from a first position to a second position or from a second position to a first position, the respective actuation member 94A, 94B is knocked out of the respective groove 120 by a resetting member 128 e.g. corotating with the second rotatable unit 84.

Optionally, a resilient member is placed in the connection between the camshaft 34 and the selection bush 122. The resilient member allows the camshaft 34 to already perform the motion for axially moving the bush 122, while the bush 122 is (temporarily) prevented from actually performing the axial movement, e.g. due to being blocked from performing the axial movement by one or more of the actuation members 94A, 94B. For example, when the first actuation member 94A is in the groove 120, the bush 122 may be prevented from moving from the first position to the second position. If, in this situation, the camshaft is rotated for axially moving the bush 122 from the first position to the second position the resilient member may be deformed. Once the first actuation member 94A is lifted out of the groove, the bush 122 may perform (or finish) the axial movement already imposed by the camshaft 34. For example, when the second actuation member 94B is in the groove 120, the bush 122 may be prevented from moving from the second position to the first position. If, in this situation, the camshaft is rotated for axially moving the bush 122 from the second position to the first position the resilient member may be deformed. Once the second actuation member 94B is lifted out of the groove, the bush 122 may perform (or finish) the axial movement already imposed by the camshaft 34.

The resilient member can be a compliant mechanism. The resilient member can be pre-tensioned, e.g. in two directions, such as two axial directions. The resilient member can e.g. be placed in the bush 122, between the bush 122 and the pin(s) 124, between the pins(s) 124 and the groove 54, and/or between the groove 54 and the camshaft 34.

Figures 10A-10C show an example of the selector 98. In this example, the selector includes one or more grooves 120 immobile relative to the axle 30. In this example, the selection bush 122 comprises a first section 122A of a first outer diameter. The second section 122B having a second outer diameter that is smaller than the first outer diameter is omitted in this example. Also in this example, the bush 122 can be axially moved by the pin 124 riding in the groove 54 of the camshaft 34. The bush 122 can be moved into a first position (igure 10A) and a second position (figure 10B).

With the bush 122 in the first position, as shown in figure 104A, the first actuation member 94A rides with its radially inward end on the outer diameter first section 122A of the bush. Hence, the first actuation member 94A is prevented from entering the groove 120. With the bush in the first position, as shown in figure 10A, the second actuation member 94B has its cutout 126B aligned with the outer diameter first section 122A of the bush.

Hence, the second actuation member 94A is enabled to enter the groove 120.

With the bush in the second position, as shown in figure 10B, the second actuation member 94B rides with its radially inward end on the outer diameter first section 122A of the bush. Hence, the second actuation member 94B is prevented from entering the groove 120. With the bush in the second position, as shown in figure 9C, the first actuation member 94A is enabled to enter the groove 120. In this example, the first actuation member 94A does not have a cutout 126A. Instead, a width of the first actuation member 94A is chosen such that with the bush in the second position the first actuation member 94A is enabled to enter the groove 120.

Once the first or second actuation member 94A, 94B enters the groove 120, the third rotatable unit 88 is temporarily halted, causing the third rotatable unit to rotate relative to the second rotatable unit 84. The third rotatable unit 88 will rotate relative to the second rotatable unit 84 from a first position (figure 6A) to a second position (figure 6B) or from a second position to a first position. Hence, the actuatable clutch S1, S2 will engage or disengage. After the third rotatable unit 88 moving from a first position to a second position or from a second position to a first position, the respective actuation member 94A, 94B is knocked out of the respective groove 120 by a resetting member 128 e.g. corotating with the second rotatable unit 84.

Figure 10C shows a side view of an example of the bush 122. In this example, the pin 124 is connected to the bush 122 via a tangential arm 124A. A proximal end of the arm 124A connects to the bush 122, while a distal end of the arm 124A connects to the pin 124. The arm is in this example made of a resilient material, such as a plastics material. The arm 124A can form the resilient member referred to above. The arm allows for the pin already moving in an axial direction of the axle 30, while the bush 122 is still prevented from axially moving by means of the first or second actuation member being positioned in a groove 120.

Figures 11A-11C show an example of the selector 98. In this example, the selector includes one or more grooves 120 immobile relative to the axle 30. In this example, the selection bush 122 comprises a first section 122A of a first outer diameter. The second section 122B having a second outer diameter that is smaller than the first outer diameter is omitted in this example. Also in this example, the bush 122 can be axially moved by the pin 124 riding in the groove 54 of the camshaft 34. The pin can e.g. be connected to the bush 122 via an arm 124A as shown in figure 10C. The pin extends through a cutout 123 in the axle 30. In an example, the bush 122 has a plurality of pins 124 connected thereto, such as 2 or 3 pins, e.g. evenly distributed about the circumference of the bush 122. The bush 122 can be moved into a first position (figure 11A) and a second position (figure 11C).

As can be seen in figures 11A-11C, the groove 54 has two legs that extend transverse to the longitudinal axis of the camshaft 34. When the pin 124 1s in one of the two legs, the bush is in a stable situation in the first or second position, respectively. The arm 124A can be tensioned in the first and/or second position, such that the bush 122 is pressed against an axial face 30A, 30B. Hence, a stable positioning of the bush 122 can be obtained. Figure 11B shows an intermediate position in which the camshaft 34 is rotated such that the pin 124 is in a slanted portion of the groove 54 that connects the two legs. The two actuation members 94A and 94B can be similar as shown in figures 9A and 9B or 10A and 10B.

The first and second actuation members 94A, 94B, can e.g. be as shown in figures 9A, 9B, 10A or 10B. With the bush 122 in the first position, as shown in figure 11A, the first actuation member 94A can ride with its radially inward end on the outer diameter first section 122A of the bush.

Hence, the first actuation member 94A is prevented from entering the groove 120. With the bush in the first position, as shown in figure 11A, the second actuation member 94B can have its cutout 126B aligned with the larger outer diameter first section 122A of the bush. Hence, the second actuation member 94A is enabled to enter the groove 120. With the bush in the second position, as shown in figure 11C, the second actuation member 94B can ride with its radially inward end on the outer diameter first section 122A of the bush. Hence, the second actuation member 94B is prevented from entering the groove 120. With the bush in the second position, as shown in figure 9C, the first actuation member 94A can have its cutout 126A aligned with the outer diameter first section 122A of the bush.

Alternatively, the first actuation member can have no cutout as described with respect to figures 10A, 10B. Hence, the first actuation member 94A is enabled to enter the groove 120. Once the first or second actuation member 94A, 94B enters the groove 120, the third rotatable unit 88 is temporarily halted, causing the third rotatable unit to rotate relative to the second rotatable unit 84. The third rotatable unit 88 will rotate relative to the second rotatable unit 84 from a first position (figure 6A) to a second position (figure 6B) or from a second position to a first position. Hence, the actuatable clutch S1, S2 will engage or disengage. After the third rotatable unit 88 moving from a first position to a second position or from a second position to a first position, the respective actuation member 94A, 94B is knocked out of the respective groove 120 by a resetting member 128 e.g. corotating with the second rotatable unit 84.

In an example, the bicycle transmission comprises an electric drive for propelling, or assisting in propelling, the bicycle. The electric drive can be mounted concentrically around the axle 30. Alternatively, the electric drive can be mounted at least partially inside the axle 30. The electric drive can comprise an electric motor. The electric motor can comprise a stator and a rotor. The electric drive can comprise a planetary gear set. The electric drive can comprise a rotation sensor and/or a position sensor.

Returning to figure 1, the bicycle transmission 1000 comprises the hub shell 51 for connection to a bicycle wheel, e.g. via spokes flanges 140.

The bicycle transmission 1000 further comprises a driver part 142 for connection to one or more sprockets 3. In this example, the driver part 142 is mounted to the wheel axle 30 via a first bearing 144, here two first bearings. The hub shell 51 is mounted to the wheel axle 30 via a second bearing 146 and to the driver part 142 via a third bearing 148. The bicycle transmission 1000 further comprises the transmission system 100. In this example, the transmission system comprises the planetary gear set 100. In this example, the transmission system 100 is positioned between the second and third bearings 146, 148. In this example, the switching mechanism S1,

S2 and the clutch mechanisms C1, C2, C3, C4 are positioned between the second and third bearings 146, 148.

The bicycle transmission 1000 further comprises control electronics 150 for controlling the actuator, e.g. the electromechanical actuator 32. In this example, the control electronics 150 are positioned beyond the second bearing 146 when seen from the transmission system 100. As can be seen in figure 1, the hub shell 51 encloses a first cavity between the second bearing 146 and the third bearing 148. The transmission system 100 is positioned in the first cavity. The control electronics 150 are positioned outside the first cavity. In this example, the control electronics 150 are mounted distally from the non drive side hub bearing 146. It is, however, possible that the control electronics 150 are mounted distally from the drive side hub bearing 148.

In the example of figure 1, the hub shell 51 extends beyond the second bearing 146 when seen from the transmission system 100 and encases the control electronics 150. The control electronics 150 are mounted, e.g. immobile, on the axle 30, such as concentrically on the axle. The control electronics comprise at least one of a controller, generator, battery, PCB, wireless receiver/transmitter, antenna, LED, charge plug, connector, or micro-chip. In this example, the control electronics are mounted behind a housing 152 housing. The housing 152 is preferably transmissive for wireless signals. The housing can e.g. be made of a plastics material.

A receiver of the control electronics 150 can be configured for receiving a shift control signal, such as from a shifter 1024. The shift control signal can be representative of a desired transmission gear (e.g. first gear, second gear, third gear, etc.). The shift control signal can be representative of upshift or downshift. The controller can be configured for, on the basis of the shift control signal controlling the actuator, such as the electromechanical actuator. Alternatively, or additionally, the controller can be configured for autonomously changing a transmission gear, e,g. on the basis of a current transmission gear, a wheel speed, a cadence, a torque, and/or a heart rate. Particularly when the transmission system comprises the generator and is configured for autonomously changing the transmission ratio, a self-contained autonomous transmission can be provided.

Optionally, characteristics of the transmission system, such as parameters on when to shift gears can be adjusted by a user, e.g. using an interface, such as on a mobile communications device, such as a smartphone, in (wireless) communication with the control electronics.

In the example of figure 1, the hub shell 51 comprises an inner hub shell 511 housing the axle 30 and an outer hub shell 510 configured for connection to the wheel. Here, the control electronics 150 are positioned to be replaceable after removing the inner hub 511 shell from the outer hub shell 510.

Figure 12 shows an example of a bicycle 1. The bicycle includes a frame 1002 and a front fork 1005. The bicycle includes a handlebar 1003. A front wheel 1011 is mounted to the front form 1005. The frame 1002 includes a rear fork 1007 having a rear wheel 1013 mounted thereto. A crank axle 1004 is mounted to the frame 1002. Pedals 1017 are connected to the crank axle 1004. A front sprocket 1009 is also connected to the crank axle 1004. The rear wheel is provided with a hub 1022. A rear sprocket 1021 1s connected to the hub. In this example, the rear sprocket 1021 is connected to the hub 1022 via the transmission system 100, e.g. as described above.

Alternatively, or additionally, the crank axle 1004 can be connected to the front sprocket 1009 via a transmission system 100, e.g. as described above.

The front sprocket 1009 drives the rear sprocket 1021 via an endless member, such as a chain or belt. The bicycle 1 in this example includes a shifter 1024 configured for transmitting a shift control signal to a receiver of the control electronics 150 of the transmission system 100.

Herein, the invention is described with reference to specific examples of embodiments of the invention. It will, however, be evident that various modifications and changes may be made therein, without departing from the essence of the invention. For the purpose of clarity and a concise description features are described herein as part of the same or separate embodiments, however, alternative embodiments having combinations of all or some of the features described in these separate embodiments are also envisaged.

In the examples, an eight-speed or nine-speed transmission system is provided using four different sun gears. It will be appreciated that it is also possible to provide the transmission system with fewer, or more different transmission ratios, such as two or three (one sun gear) four or five (two sun gears), six or seven (three sun gears), ten or eleven (five sun gears), twelve or thirteen (six sun gears), fourteen or fifteen (seven sun gears), sixteen or seventeen (eight sun gears), eighteen or nineteen (nine sun gears), or twenty or twenty-one (ten sun gears) different transmission ratios. The number of planet ger parts of different radii of the stepped planet gears can correspond to the number of different sun gears.

In the example, each sun gear is associated with an actuatable bidirectional clutch mechanism configured for in a first mode selectively preventing rotation of the at least one sun gear in a first rotational direction about the axle (and optionally allowing rotation of the at least one sun gear in an opposite second rotational direction about the axle), and in a second mode selectively preventing rotation of the at least one sun gear in the opposite second rotational direction about the axle (and optionally allowing rotation of the at least one sun gear in the first rotational direction about the axle), for providing two different transmission ratios with one sun gear.

It will be appreciated that it is possible that the transmission system further includes one or more sun gears having an associated unidirectional clutch mechanism configured for in a first mode selectively preventing rotation of the at least one sun gear in a first rotational direction about the axle (and optionally allowing rotation of the at least one sun gear in the opposite second rotational direction about the axle), and in a second mode allowing rotation of the at least one sun gear the first rotational direction (and optionally allowing rotation of the at least one sun gear in the opposite second rotational direction about the axle).

However, other modifications, variations, and alternatives are also possible. The specifications, drawings and examples are, accordingly, to be regarded in an illustrative sense rather than in a restrictive sense.

In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word ‘comprising’ does not exclude the presence of other features or steps than those listed in a claim.

Furthermore, the words ‘a’ and ‘an’ shall not be construed as limited to ‘only one’, but instead are used to mean ‘at least one’, and do not exclude a plurality. The mere fact that certain measures are recited in mutually different claims does not indicate that a combination of these measures cannot be used to an advantage.

Claims

Conclusions

1. A bicycle transmission comprising: an axle, such as a wheel axle or an intermediate shaft in a crank transmission, configured to be non-rotatably attached to a frame of the bicycle; at least one sun gear rotatably mounted about the axle; at least one clutch mechanism for selectively preventing rotation of the at least one sun gear in at least one rotational direction about the axle; and a camshaft mounted in the axle for actuating the at least one clutch mechanism.

2. The bicycle transmission of claim 1, further comprising an electromechanical actuator, such as an electric motor, on or in the shaft and configured to move, such as rotate, the camshaft.

3. Bicycle transmission, comprising: an axle; a clutch mechanism about and/or in the axle; and an electromechanical actuator, such as an electric motor, in the axle and configured to operate the clutch mechanism.

4. The bicycle transmission of claim 3, further comprising a camshaft mounted in the axle to be moved by the electromechanical actuator, the camshaft configured to operate the clutch mechanism.

5. The bicycle transmission of claim 3 or 4, wherein the axle 1 is configured to be non-rotatably attached to a frame of the bicycle, the transmission further comprising:

at least one sun gear rotatably mounted about the axis, wherein] the clutch mechanism is configured to selectively prevent rotation of the at least one sun gear in at least one rotational direction about the axis.

6. A bicycle transmission comprising: an axle, such as a wheel axle or a crankshaft, configured to be non-rotatably attached to a frame of the bicycle; a plurality of sun gears rotatably mounted about the axle; a plurality of clutch mechanisms for selectively preventing rotation of one or more of the plurality of sun gears in at least one rotational direction about the axle; and a camshaft comprising a single cam profile for actuating the plurality of clutch mechanisms.

7. Bicycle transmission according to claim 6, wherein the camshaft is mounted in the axle.

8. A bicycle transmission according to claim 6 or 7, further comprising an electromechanical actuator, such as an electric motor, on or in the shaft and configured to move, such as rotate, the camshaft.

9. Bicycle transmission according to any of claims 1 to 5, wherein the camshaft comprises a single cam profile for operating the plurality of clutch mechanisms.

10. A bicycle transmission according to claim 1 or 2, or any of claims 5 to 9, wherein each clutch mechanism comprises at least one pawl configured to be actuated by the camshaft such that the at least one pawl is selectively engaged or disengaged with the respective sun gear.

11. The bicycle transmission of claim 10, wherein the at least one pawl is configured to move radially relative to the axle.

12. A bicycle transmission according to claim 1 or 2, or any one of claims 4 to 11, wherein each clutch mechanism has an associated selector sleeve, and wherein the camshaft includes one or more grooves for axially moving the selector sleeve(s).

13. A bicycle transmission according to claim 2, 3, 4, or 5, or any of claims 8 to 12 as dependent on claim 2, 3, 4, or 5, comprising a resilient member, such as a compliant mechanism, connecting the camshaft to the electromechanical actuator.

14. Bicycle transmission according to claim 13, wherein the resilient member is biased in two opposite directions.

15. Bicycle transmission according to any one of claims 1 to 14, comprising an electric drive for driving or assisting in driving the bicycle, the electric drive being mounted concentrically in and/or outside the axle or mounted on a further axle, such as parallel to the axle.

16. Bicycle transmission according to claim 15, wherein the electric drive comprises an electric motor and optionally a planetary gear set.

17. Bicycle transmission according to any one of claims 1 to 16, wherein the camshaft or the electric drive comprises a rotation sensor and/or a position sensor.

18. Bicycle transmission according to any of claims 1 to 17, further comprising control electronics for controlling the electromechanical actuator, wherein optionally the control electronics are mounted distal to a drive side or non-drive side hub bearing.

19. A bicycle transmission, as claimed in any one of claims 1 to 18, comprising: a hub shell for connection to a bicycle wheel; a wheel axle; a drive member for connection to one or more sprockets, the drive member being mounted to the wheel axle via a first bearing, and the hub shell being mounted to the wheel axle via a second bearing and to the drive member via a third bearing; a transmission system providing a plurality of selectably different gear ratios between the drive member and the hub shell, the transmission system being positioned between the second and third bearings; an electromechanical actuator for operating a shift from one gear ratio to another; control electronics for controlling the electromechanical actuator; the control electronics being positioned beyond the second bearing as viewed from the transmission system.

20. A bicycle transmission, as claimed in any one of claims 1 to 18, comprising: a hub shell for connection to a bicycle wheel; a wheel axle; a drive member for connection to one or more gears, the drive member being mounted to the wheel axle via a first bearing, and the hub shell being mounted to the wheel axle via a second bearing and to the drive member via a third bearing, the hub shell enclosing a first recess between the second bearing and the third bearing; a transmission system providing a plurality of selectably different gear ratios between the drive member and the hub shell, the transmission system being positioned in the first recess; an electromechanical actuator for operating a shift from one gear ratio to another; control electronics for controlling the electromechanical actuator; the control electronics being positioned outside the first recess.

21. Bicycle transmission according to claim 19 or 20, wherein the hub shell extends beyond the second bearing as seen from the transmission system and encloses the control electronics.

22. Bicycle transmission according to any of claims 18 to 21, wherein the control electronics are mounted, e.g. immobile, on the axle, such as concentrically on the axle.

23. Bicycle transmission according to any of claims 18 to 22, wherein the control electronics comprises at least one of a generator, battery, PCB, wireless receiver/transmitter, antenna, LED, charging plug, connector, or micro-chip.

24. Bicycle transmission according to any of claims 18 to 23, wherein the control electronics are mounted in, behind and/or connected to a plastic housing.

25. The bicycle transmission of any of claims 18 to 24, wherein the hub shell comprises an inner hub shell receiving the axle and an outer hub shell configured for connection to the wheel, the control electronics being positioned to be replaceable upon removal of the inner hub shell from the outer hub shell.

26. Bicycle gear hub comprising the bicycle gear according to any one of claims 1 to 25.

27. Bicycle crank transmission comprising the bicycle transmission according to any of claims 1-18 or 22-25.

28. Bicycle comprising the bicycle gear hub according to claim 26 and/or the bicycle crank transmission according to claim 27.