KR102784665B1 - Transmission for bicycle crank - Google Patents

Abstract

A bicycle crank shifting device is disclosed. According to one embodiment of the present invention, a bicycle crank shifting device comprises: a ring gear portion having a direct-coupled ratchet arranged on an outer side thereof and gear teeth formed on an inner surface thereof; a crank cover having direct-coupled ratchet teeth formed on an inner surface thereof to selectively mesh with the direct-coupled ratchet and a coupling shaft formed thereon; a sun gear portion mounted on the coupling shaft; a reduction gear portion including an eccentric guide having an eccentric hole formed therein and an eccentric gear coupled to the eccentric guide and having one area meshed with the ring gear portion and another area meshed with the sun gear portion; a chainring housing that rotates together with the ring gear portion, having the direct-coupled ratchet arranged on one surface thereof, and a chainring coupling portion formed on an outer surface thereof; And a clutch part which selectively engages the direct ratchet with the direct ratchet teeth; the sun gear part includes a sun gear including a first gear having a sun gear tooth formed on an outer surface thereof and engaging with the eccentric gear, and a second gear formed on one surface of the first gear and having a sun gear ratchet tooth formed on an outer surface thereof; and a sun gear ratchet which is disposed on the crank cover and engages with the sun gear ratchet teeth. According to the present invention, a crank transmission device is provided which has a built-in transmission and enables transmission with only a single chainring, enables simplification and reduction in weight of the configuration, has excellent durability of continuously engaged ratchets/gears, and prevents concentration of applied stress, so that it can be used safely.

Description

TRANSMISSION FOR BICYCLE CRANK

The present invention relates to a bicycle crank shifting device, and more particularly, to a bicycle crank shifting device having a built-in transmission.

In general, the gear shift of a bicycle is installed to enable pedaling with a certain force and speed depending on the riding condition. Bicycle shifting is divided into front gear shifting and rear gear shifting. Front gear shifting is performed by overlapping chainrings with different numbers of teeth, and rear gear shifting is performed by overlapping sprockets with different numbers of teeth. The gear ratio determined by the number of teeth of the chainring (front gear) and sprocket (rear gear) is expressed as a difference in the riding speed of the bicycle under the same pedaling conditions.

However, the front gear of a conventional bicycle has a problem in that the chain frequently comes off the chainring during the shifting process due to the shift mechanism that forcibly moves the position of the chain. In addition, it is not easy to reattach a detached chain to the chainring, and the user's hands or clothes, etc., may become contaminated by the lubricant applied to the chain during the chain mounting process.

Furthermore, when the front gear of a bicycle is changed by stacking multiple chainrings and moving the position of the chain, there is a problem in that there is a limit to the miniaturization and weight reduction of the device.

In order to solve these problems, the applicant has registered a “bicycle crank shifting device” under Patent No. 10-1701289.

The literature has a disadvantage in that the inner and outer surfaces of a single configuration mesh with the eccentric gear and the sun gear ratchet, respectively, as the gear teeth are formed on the outer surface of the sun gear and the sun gear ratchet teeth are formed on the inner surface, thereby applying excessive stress.

In addition, in order to prevent reverse rotation of the chainring housing during shifting, an internal ratchet and an external ratchet must be formed in the chainring housing, and a reverse rotation prevention ring/reverse rotation prevention clutch that engages this must be used, but this may also have disadvantages in durability.

Republic of Korea Patent No. 10-2186944 (2020.11.30) Republic of Korea Patent No. 10-1701289 (2017.01.24)

A bicycle crank shifting device according to one embodiment of the present invention aims to provide a bicycle crank shifting device having a built-in transmission that shifts gears using only a single chainring.

In addition, a bicycle crank shifting device according to one embodiment of the present invention aims to provide a bicycle crank shifting device capable of simplifying the configuration and reducing the weight.

In addition, the bicycle crank shifting device according to one embodiment of the present invention aims to provide a crank shifting device that is safe to use as it has excellent durability of continuously meshed ratchets and gears and prevents concentration of applied stress.

The tasks of the present invention are not limited to the technical tasks mentioned above, and other technical tasks not mentioned will be clearly understood by those skilled in the art from the description below.

According to one embodiment of the present invention, a bicycle crank shifting device comprises: a ring gear portion having a direct-coupled ratchet arranged on the outside and gear teeth formed on an inner surface; a crank cover having direct-coupled ratchet teeth formed on the inner surface to selectively mesh with the direct-coupled ratchet and a coupling shaft formed; a sun gear portion mounted on the coupling shaft; a reduction gear portion including an eccentric guide having an eccentric hole formed therein and an eccentric gear coupled to the eccentric guide and having one area meshed with the ring gear portion and another area meshed with the sun gear portion; a chainring housing that rotates together with the ring gear portion, having the direct-coupled ratchet arranged on one surface, and a chainring coupling portion formed on an outer surface; And a clutch part which selectively engages the direct ratchet with the direct ratchet teeth; the sun gear part includes a sun gear including a first gear having sun gear teeth formed on an outer surface thereof and meshing with the eccentric gear, and a second gear formed on one surface of the first gear and having sun gear ratchet teeth formed on an outer surface thereof; a sun gear ratchet which is disposed on the crank cover and meshes with the sun gear ratchet teeth.

In an embodiment, the sun gear ratchet teeth may have an inclination along one direction.

In an embodiment, the first gear and the second gear may be positioned at different heights along the thickness direction of the sun gear.

According to one embodiment of the present invention, a bicycle crank shifting device comprises: a ring gear portion having a direct-coupled ratchet arranged on the outside and gear teeth formed on an inner surface; a crank cover having direct-coupled ratchet teeth formed on the inner surface to selectively mesh with the direct-coupled ratchet and a coupling shaft formed; a sun gear portion mounted on the coupling shaft; a reduction gear portion including an eccentric guide having an eccentric hole formed therein and an eccentric gear coupled to the eccentric guide and having one area meshed with the ring gear portion and another area meshed with the sun gear portion; a chainring housing that rotates together with the ring gear portion, having the direct-coupled ratchet arranged on one surface and a chainring coupling portion formed on an outer surface; and a clutch that selectively meshes the direct-coupled ratchet with the direct-coupled ratchet teeth; wherein the sun gear portion comprises: a sun gear having sun gear teeth formed on an outer surface to mesh with the eccentric gear and having sun gear teeth formed on one surface; It includes a ratchet tooth portion having one side disposed on the crank cover and having ratchet teeth formed on the other side to mesh with the sun gear teeth.

In an embodiment, the above-described gear part comprises: a cover disposed between the above-described gear part and the above-described reduction gear part;

One side is fixed to the cover and may include an elastic member that allows the sun gear to be pressed against the ratchet tooth portion.

In an embodiment, the sun gear may have an annular mounting groove formed therein, and one end of the elastic member may be fixed to the annular mounting groove, and the other end may be fixed to the cover.

In an embodiment, the crank cover may further include a one-way bearing that prevents the chainring housing from rotating in the reverse direction when the crank cover rotates in the reverse direction.

In an embodiment, the chainring housing further includes a BB holder replaceably mounted on a surface thereof, wherein a protruding side wall formed in an annular shape is formed on the other side thereof, and the one-way bearing can be arranged between the side wall and the BB holder.

In an embodiment, the direct ratchet may be elastically supported along the radial direction of the ring gear portion.

In an embodiment, an operating projection is formed on one side of the direct-coupled ratchet, and the clutch has a receiving portion for receiving the operating projection and a support portion for supporting the operating projection alternately formed at equal intervals along the circumferential direction on the inner surface, and a plurality of elastic ratchets are formed at equal intervals on the outer surface, and can be rotated to determine whether the direct-coupled ratchet is deployed.

According to embodiments of the present invention, at least the following effects are achieved.

According to the bicycle crank shifting device according to the present invention, shifting can be performed with only a single chainring.

In addition, in the embodiment, the area where the sun gear meshes with the eccentric gear and the area where the sun gear meshes with the sun gear ratchet are positioned at different heights along the thickness direction, so that the applied stress can be distributed, resulting in excellent durability.

In addition, in the embodiment, the area where the sun gear meshes with the eccentric gear and the area where the sun gear meshes with the ratchet tooth portion are positioned at different heights along the thickness direction, so that the applied stress can be distributed, resulting in excellent durability.

Additionally, the crank as a whole can be simplified and made lighter.

In addition, by adopting a one-way bearing to prevent the chainring housing from rotating backwards when shifting, the chainring housing can avoid having a complex structure such as a ratchet inside, and the reverse rotation prevention structure that engages with the chainring housing is unnecessary, so the overall structure can be simplified, and the meshing structure is omitted, resulting in excellent durability.

The effects according to the present invention are not limited to those exemplified above, and more diverse effects are included in this specification.

Figure 1 is a perspective view of a bicycle crank gear according to the first embodiment of the present invention.
Figure 2 is a perspective view of a crank cover of a bicycle crank shifting device according to the first embodiment of the present invention.
Figure 3 is an exploded perspective view of the crank cover and the sun gear of the bicycle crank gear according to the first embodiment of the present invention.
Figure 4 is an exploded perspective view of the bottom surface of the crank cover and the sun gear of the bicycle crank gear according to the first embodiment of the present invention.
Figure 5 is an explanatory drawing of the sun gear part of the bicycle crank speed changer according to the first embodiment of the present invention.
Figure 6 is a perspective view of the ring gear and clutch of the bicycle crank gearbox according to the first embodiment of the present invention.
Figure 7 is a plan view of a clutch of a bicycle crank gear according to the first embodiment of the present invention.
Figure 8 is a perspective view of a reduction gear section of a bicycle crank speed device according to the first embodiment of the present invention.
Figure 9 is an exploded perspective view of the reduction gear part of a bicycle crank speed device according to the first embodiment of the present invention.
Figure 10 is a diagram explaining the relationship between gears of a bicycle crank gearbox according to the first embodiment of the present invention.
Figure 11 is a perspective view of a chainring housing of a bicycle crank gear according to the first embodiment of the present invention.
Figure 12 is a relationship diagram between a chainring housing and a one-way bearing of a bicycle crank gear according to the first embodiment of the present invention.
Figure 13 is an explanatory diagram of a high-speed driving of a bicycle crank gear according to the first embodiment of the present invention.
Figure 14 is an explanatory diagram of a low-speed driving of a bicycle crank gear according to the first embodiment of the present invention.
Figure 16 is an exploded perspective view of the crank cover and the sun gear of the bicycle crank gear according to the second embodiment of the present invention.
Figure 16 is an exploded perspective view of the bottom surface of the crank cover and the sun gear of the bicycle crank shifting device according to the second embodiment of the present invention.
Fig. 17 is a perspective view of the sun gear portion of a bicycle crank speed changer according to the second embodiment of the present invention.

The present invention can be modified in various ways and has various embodiments, and specific embodiments are illustrated in the drawings and described in detail in the detailed description. The effects and features of the present invention, and the methods for achieving them, will become clear with reference to the embodiments described in detail below together with the drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various forms, and it should be understood to include all modifications, equivalents, or substitutes included in the spirit and technical scope of the present invention.

Before the explanation, the terms described in the detailed description will be explained. In the following embodiments, the terms first, second, etc. are not used in a limiting sense, but are used for the purpose of distinguishing one component from another component. Therefore, it goes without saying that the first component mentioned below may also be the second component within the technical idea of the present invention. In addition, the singular expression includes the plural expression unless the context clearly indicates otherwise. In addition, the terms such as 'include' or 'have' mean that there are features, numbers, steps, operations, components, parts or a combination thereof described in the specification, and do not exclude in advance the possibility that one or more other features or components may be added.

In addition, in the drawings, the sizes of components may be exaggerated or reduced for convenience of explanation. For example, the sizes and thicknesses of each component shown in the drawings are arbitrarily shown for convenience of explanation, and therefore the present invention is not necessarily limited to what is shown.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the attached drawings. In describing with reference to the attached drawings, identical or corresponding components are given the same drawing reference numerals, and redundant descriptions thereof are omitted.

A bicycle crank shifting device according to one embodiment of the present invention is a crank shifting device having a built-in transmission that shifts gears using only a single chainring, allowing for a simplified and lightweight configuration, excellent durability of continuously meshed ratchets/gears, and preventing concentration of applied stress, thereby enabling safe use.

A bicycle crank shifting device (1000) according to a first embodiment of the present invention includes a crank cover (100), a sun gear portion (200), a ring gear portion (300), a clutch (400), a reduction gear portion (500), a chainring housing (600), a BB holder (700), and an eccentric bearing (800).

FIG. 1 is a perspective view of a bicycle crank shifting device according to a first embodiment of the present invention, FIG. 2 is a perspective view of a crank cover of the bicycle crank shifting device according to the first embodiment of the present invention, FIG. 3 is an exploded perspective view of a crank cover and a sun gear of the bicycle crank shifting device according to the first embodiment of the present invention, FIG. 4 is a bottom exploded perspective view of a crank cover and a sun gear of the bicycle crank shifting device according to the first embodiment of the present invention, and FIG. 5 is an explanatory drawing of the sun gear of the bicycle crank shifting device according to the first embodiment of the present invention.

The crank cover (100) is configured to be coupled with a pedal shaft (not shown) and rotate together with the pedal shaft (not shown) by the user's pedaling. The rotation of the crank cover (100) transmits driving power to the wheels, allowing the bicycle to run.

A coupling shaft (110) is formed in the center of the inner surface of the crank cover (100) to be coupled with a spindle (not shown) of a bottom bracket (not shown).

A groove (111) surrounding a coupling shaft (110) may be formed in the inner central portion of the crank cover (100). A sun gear ratchet (220) described later may be placed in this groove (111).

On the inner wall of the crank cover (100), clutch ratchet teeth (120) and direct ratchet teeth (130) are formed along the height direction on the inner surface. Specifically, in the drawing, clutch ratchet teeth (120) are formed on the lower part of the inner wall of the crank cover (100), and direct ratchet teeth (130) are formed on the clutch ratchet teeth (120). The clutch ratchet teeth (120) mesh with the elastic ratchet (410) of the clutch (400), and the direct ratchet teeth (130) are configured to mesh with the direct ratchet (330) when the direct ratchet (330) is extended from the ring gear (300).

The crankshaft (200) is configured to transmit driving force when the crank cover (100) rotates.

The sun gear unit (200) includes a sun gear (210) and a sun gear ratchet (220).

In this embodiment, the sun gear (210) is provided as a two-stage gear, and thus the first gear (211) and the second gear (212) can be provided as an integral part. The sun gear (210) has an axial hole formed therein and is mounted on the coupling shaft (110), and the first gear (211) has a sun gear tooth (211a) formed on the outer surface thereof, and one area meshes with the eccentric gear (520). When the bicycle is driven, the sun gear (210) rotates. When in a high gear, it idles, and when in a low gear, it rotates together with the crank cover (100). The rotation of the sun gear portion (200) will be described in detail in the operating section described later.

And the second gear (212) is formed on one side of the first gear (211) and is provided with a smaller size than the first gear (211), and a sun gear ratchet tooth (212a) is formed on the outer surface. The second gear (212) is arranged in the groove (111), and the first gear (211) is larger than the size of the groove (111), and since the second gear (212) is formed on one side, it is arranged on the bottom surface of the crank cover (100).

The sun gear ratchet teeth (212a) are engaged with the sun gear ratchet (220) arranged in the groove (111) of the crank cover (100). The sun gear ratchet teeth (212a) are formed to be inclined in one direction so that the sun gear ratchet (220) can only rotate in one direction when engaged and cannot rotate in the opposite direction. That is, the sun gear ratchet teeth (212a) are formed to be inclined in one direction based on the radial direction of the shaft hole so that the sun gear ratchet (220) can only rotate in one direction when engaged.

The sun gear part (200) is only allowed to rotate in the forward direction (counterclockwise in FIG. 5) due to the engagement of the sun gear ratchet teeth (212a) and the sun gear ratchet (220). Here, the forward direction means the direction in which the crank cover (100) rotates so that the bicycle moves forward, and the reverse direction means the opposite direction of the forward direction. The sun gear ratchet (220) may be provided to be elastically supported toward the sun gear ratchet teeth (212a) by a spring (not shown) or the like, and may be provided to always mesh with the sun gear ratchet teeth (212a).

The fatigue test method of the crank assembly is specified in “Bicycles - Two-wheeled bicycle safety requirements - Part 8: Test methods for pedals and drive systems” of the Korean Industrial Standard KS R ISO 4210－8. When a test is conducted with a crank positioned at 45° from the horizontal to simulate the force caused by the pedal, a vertical dynamic force of 1,300 N is repeatedly applied to the pedal spindle adapter of the crank 100,000 times. The present invention satisfies the above test conditions through a structure in which the sun gear (210) is an integral part of the first gear (211) and the second gear (212), and the first gear (211) meshes with the eccentric gear (520) and the second gear (212) meshes with the sun gear ratchet (220) as a sun gear ratchet tooth.

In the invention of the previous inventor, such as Patent No. 10-1701289, the sun gear has gear teeth formed on the outer circumference and sun gear ratchet teeth formed on the inner circumference, so that the inner and outer surfaces of the single configuration mesh with the eccentric gear and the sun gear ratchet, respectively, and there is a disadvantage in that excessive stress is applied. However, in the present embodiment, the sun gear (210) is divided into a first gear (211) and a second gear (212), and the first gear (211) meshes with the eccentric gear (520) and the second gear (212) meshes with the sun gear ratchet (220), so that the above safety test conditions can be satisfied.

In other words, the sun gear (210) has a first gear (211) formed with a sun gear tooth (211a) that meshes with the eccentric gear (520) and a second gear (212) formed with a sun gear ratchet tooth (212a) that meshes with the sun gear ratchet (220), which are positioned at different heights along the thickness direction of the sun gear (210), so that the applied stress can be distributed, resulting in excellent durability.

FIG. 6 is a perspective view of a ring gear and a clutch of a bicycle crank shifting device according to a first embodiment of the present invention, and FIG. 7 is a plan view of a clutch of a bicycle crank shifting device according to a first embodiment of the present invention.

The ring gear part (300) is a component that determines the high and low gears of bicycle driving. The ring gear part (300) is arranged on one surface of the base plate (610). Ring gear teeth (310) are formed on the inner surface of the ring gear part (300), and some of the ring gear teeth (310) are arranged to mesh with the eccentric gear (520). A direct ratchet arrangement part (320) on which a direct ratchet (330) is arranged may be protrudingly formed on the outer surface of the ring gear part (300). The direct ratchet arrangement parts (320) are formed spaced apart from each other, and a position-fixing protrusion (613) formed on one surface of the base plate (610) may be arranged between the direct ratchet arrangement parts (320). The position of the direct ratchet (330) may be determined by the direct ratchet arrangement part (320).

The direct ratchet (330) is configured to selectively engage with the direct ratchet teeth (120), and is divided into high and low stages depending on whether the direct ratchet (330) engages. The direct ratchet (330) is provided to be elastically supported outwardly along the radial direction of the ring gear portion (300). As an example, an elastic member is provided, and the direct ratchet (330) is coupled to the elastic member so as to be elastically supported in a direction away from the virtual center of the ring gear portion (300). As an example, the elastic member may be provided as a plate spring, and may be provided in the direct ratchet arrangement portion (320). At this time, the plate spring may be fixed to the direct ratchet arrangement portion (320) and the direct ratchet (300). An elastic member is interposed between the direct ratchet (330) and the direct ratchet arrangement (320) to elastically support the direct ratchet (330) toward the outside (i.e., away from the imaginary center of the ring gear portion (300)), and the elastically supported direct ratchet (330) is engaged with the direct ratchet teeth (120).

A plurality of direct ratchets (330) are provided and spaced apart. In this embodiment, four direct ratchets (330) are provided, and accordingly, four direct ratchet arrangement parts (320) are also provided. However, the number of direct ratchets (330) is not limited thereto. An operating projection (331) is provided on one side of the direct ratchet (330). Depending on the positional relationship between the operating projection (331) and the clutch (400), the direct ratchet (330) can be deployed or the elastic member can be compressed and folded.

The clutch (400) is mounted on one side of the ring gear (300). On the outer surface of the clutch (400), a plurality of elastic ratchets (410) are formed spaced apart along the circumferential direction. The plurality of elastic ratchets (410) mesh with the clutch ratchet teeth (120) when the crank cover (100) rotates in the reverse direction. On the inner surface of the clutch (400), a receiving portion (420) for receiving an operating projection (331) and a supporting portion (430) for supporting the operating projection (331) are alternately formed along the circumferential direction. The operating projection (331) is supported by the supporting portion (430) or received in the receiving portion (420) by the rotation of the clutch (400).

FIG. 8 is a perspective view of a reduction gear portion of a bicycle crank transmission device according to a first embodiment of the present invention, FIG. 9 is an exploded perspective view of a reduction gear portion of a bicycle crank transmission device according to a first embodiment of the present invention, and FIG. 10 is a diagram explaining the relationship between gears of a bicycle crank transmission device according to the first embodiment of the present invention.

The reduction gear unit (500) is configured to reduce the ring gear (300) at a low speed. Specifically, the reduction gear unit (500) is configured to receive the rotational power of the crank cover (100) from the sun gear (210) at a low speed and rotate the ring gear (300) at a reduced rotational speed. The reduction gear unit (500) includes an eccentric guide (510) and an eccentric gear (520). An eccentric hole (511) is formed in the eccentric guide (510). The eccentric guide (510) is fixedly installed on one side of the coupling shaft (110), and the centers of the eccentric hole (511) and the coupling shaft (110) are coincident. In addition, the eccentric guide (510) is arranged inside the ring gear (300) and the center of the eccentric hole (511) is arranged to be the same as the center of the ring gear (300). A bearing (512) can be installed in the eccentric hole (511).

The eccentric gear (520) is provided to be rotatable along the outer surface of the eccentric guide (510). Depending on the position of the eccentric guide (510), one area of the gear teeth of the eccentric gear (520) meshes with the ring gear portion (300), and the other area meshes with the sun gear portion (200). The eccentric gear (520) rotates in the same direction as the sun gear portion (200) to transmit the reduced rotational power to the ring gear portion (300), and as a result, the eccentric gear (520) is significantly less likely to be worn or damaged than a planetary gear.

FIG. 11 is a perspective view of a chainring housing of a bicycle crank gear according to the first embodiment of the present invention.

The chainring housing (600) includes a base plate (610) on which a ring gear part (300) is fixedly installed, and a chainring connecting part (620) formed circumferentially spaced apart on the outer surface of the base plate (610) and connected to a chainring on the outer surface.

In this embodiment, the chainring housing (600) is provided to be separated from the chainring (not shown) so that it can be replaced according to preference. However, this is not necessarily limited to this, and the chainring housing (600) and the chainring (not shown) may be formed as one piece.

At this time, a plurality of arms (621) to which a chainring is connected are formed on one side of the chainring connecting portion (620). A recessed portion (630) may be formed on each of the plurality of arms (621). By forming the recessed portion (630), the crank can be made lighter.

Meanwhile, one side of the base plate (610) is formed sunken and a protruding first side wall (611) is formed at the edge, and a protruding annular second side wall (612) is formed at the center of the other side of the base plate (610).

FIG. 12 is a diagram showing the relationship between a chainring housing and a one-way bearing of a bicycle crank gear according to the first embodiment of the present invention.

As described above, a ring gear part (300) is arranged on one side of the base plate (610). In addition, a BB holder (700) is mounted on the other side of the base plate (610). The BB holder (700) is formed in a shape corresponding to an end of the bottom bracket, which is to enable the present invention to be easily installed on various types of bottom brackets (B) with different specifications depending on the manufacturer by replacing the BB holder (700).

At this time, the inner surface of the bib holder (700) is formed to be spaced apart from the outer surface of the second side wall (612) by a predetermined distance. In addition, a one-way bearing is arranged between the base plate (610) and the bib holder (700). The one-way bearing (800) is a bearing that can only rotate in a specific direction and has a mechanism that prevents rotation in the opposite direction.

A one-way bearing (800) can rotate freely in a particular direction, but cannot move in the opposite direction due to friction or a locking mechanism.

When the user rotates the crank cover (100) in the reverse direction for shifting, the crank cover (100) and the chainring housing (600) are not directly connected, but are in close contact, so a weak rotational force is transmitted to the chainring housing (600), and rotation of the chainring housing (600) needs to be blocked. On the other hand, when the user moves the bicycle backward, the rear wheel of the bicycle rotates, and a strong rotational force is transmitted to the chainring housing (600) through the chain.

The one-way bearing (800) prevents the chainring housing (600) from rotating in the reverse direction with respect to the coupling shaft (110) when shifting, thereby enabling the shifting mechanism to operate smoothly, and prevents damage to the bicycle by allowing the chainring housing (600) to rotate in the reverse direction when the bicycle is moving backwards.

In the inventor's prior art patent No. 10-1701289, etc., the rotation of the chainring housing is prevented through the structure of a reverse rotation prevention ring in which an internal ratchet is formed on the inner surface of the base plate, an external ratchet is formed on the outer surface, and a plurality of elastic catches are formed spaced apart on the inner and outer surfaces. However, in this case, the internal ratchet and the external ratchet must be formed on the chainring housing, and the reverse rotation prevention ring and the ratchet engagement structure are formed, which raises concerns about reduced durability, etc.

However, in the present embodiment, a second annular side wall (612) protruding from the center of the base plate (610) is formed, and a one-way bearing (800) is placed between the base plate (610) and the BB holder (700), so that a complex structure such as the ratchet engagement structure above is unnecessary and durability is excellent.

Next, the operation of a transmission-integrated crank assembly according to one embodiment of the present invention will be described.

FIG. 13 is an explanatory drawing of a bicycle crank gear according to a first embodiment of the present invention when traveling at a high gear, and FIG. 14 is an explanatory drawing of a bicycle crank gear according to a first embodiment of the present invention when traveling at a low gear.

For convenience, the operation of the crank assembly built into the transmission according to the present embodiment is described in the order of high gear - shift - low gear.

1. High level

The direct ratchet (330) of the ring gear (300) is deployed by the elastic restoring force of the elastic member and engages with the direct ratchet teeth (130) of the crank cover (100).

Therefore, when the user steps on the pedal to rotate the crank cover (100) in the forward direction, the crank cover (100) directly rotates the ring gear (300) at the same rotational speed. The reduction gear (500) rotates due to the rotation of the ring gear (300), and the sun gear (210) receives the rotational power of the ring gear (300) in reverse through the reduction gear (500) and rotates at a faster rotational speed than the crank cover (100).

2. Gear shifting

The user turns the pedal backward to rotate the crank cover (100) in the reverse direction. As the crank cover (100) rotates in the reverse direction, the clutch ratchet teeth (120) of the crank cover (100) engage with the elastic ratchet (410) of the clutch (400). Accordingly, the crank cover (100) rotates the clutch (400) in the reverse direction. At this time, the chainring housing (600) is blocked from reverse rotation by the one-way bearing (800), and the clutch (400) slides and rotates on the installed ring gear (300).

Continuing, each time the clutch (400) is rotated at a predetermined angle, the operating projection (331) that is in contact with the inner surface of the clutch (400) is received in the receiving portion (420) or supported by the support member (430), so that the direct ratchet (330) is deployed or folded.

More specifically, when the operating projection (331) is received in the receiving portion (420), the direct ratchet (330) is deployed to the outside of the ring gear portion (300) by an elastic mechanical element, and the deployed direct ratchet (330) meshes with the direct ratchet teeth (130). In this case, the ring gear portion (300) is directly connected to the crank cover (100) and can rotate at the same rotational speed.

When the operating projection (331) is supported on the support member (430), the direct ratchet (330) is pressurized and folded, and the engagement with the direct ratchet teeth (130) is released. In this case, the ring gear portion (300) is connected to the sun gear (210) through the reduction gear portion (500) and can rotate at a lower rotational speed than the crank cover (100).

That is, the direct-coupled ratchet (330) that is elastically supported by the crank cover (100) rotates in the reverse direction is expanded or folded, thereby causing gear shifting.

3. Low

In the low gear case, the direct ratchet (330) of the ring gear (300) is folded and does not mesh with the direct ratchet teeth (130) of the crank cover (100).

Accordingly, when the crank cover (100) rotates in the forward direction, there is no engagement between the ring gear (300) and the crank cover (100), so they do not directly rotate, and the sun gear (210) rotates in the forward direction around the coupling axis (110) of the crank cover (100). The meshed reduction gear part (500) rotates due to the rotation of the sun gear (210), and the ring gear (300) is decelerated and rotated through the reduction gear part (500).

That is, in this embodiment, by rotating the crank cover (100) in the reverse direction to determine whether the direct ratchet (330) is deployed, the ring gear (300) is directly rotated at the same rotational speed as the crank cover (100), or the ring gear (300) is rotated at a reduced rotational speed through the sun gear (210) and the reduction gear unit (500).

Next, a bicycle crank gear shifting device according to a second embodiment of the present invention will be described.

FIG. 16 is an exploded perspective view of a crank cover and a sun gear of a bicycle crank shifting device according to a second embodiment of the present invention, FIG. 16 is an exploded perspective view of a bottom surface of a crank cover and a sun gear of a bicycle crank shifting device according to a second embodiment of the present invention, and FIG. 17 is a perspective view of a sun gear of a bicycle crank shifting device according to a second embodiment of the present invention.

A bicycle crank shifting device (2000) according to a second embodiment of the present invention includes a crank cover (100), a sun gear portion (900), a ring gear portion (300), a clutch (400), a reduction gear portion (500), a chainring housing (600), a BB holder (700), and an eccentric bearing (800).

Duplicate descriptions of the same configuration as the first embodiment are omitted. However, some duplicate descriptions may be provided for explanation purposes.

The crank cover (100) is configured to be coupled with a pedal shaft (not shown) and rotate together with the pedal shaft (not shown) by the user's pedaling. The rotation of the crank cover (100) transmits driving power to the wheels, allowing the bicycle to run.

A coupling shaft (110) is formed in the center of the inner surface of the crank cover (100) to be coupled with a spindle (not shown) of a bottom bracket (not shown).

A groove may be formed in the inner central portion of the crank cover (100) to surround the coupling shaft (110). A ratchet tooth portion (920) described later may be placed in this groove.

On the inner wall of the crank cover (100), clutch ratchet teeth (120) and direct ratchet teeth (130) are formed along the height direction on the inner surface. Specifically, clutch ratchet teeth (120) are formed on the lower part of the inner wall of the crank cover (100), and direct ratchet teeth (130) are formed on the clutch ratchet teeth (120). The clutch ratchet teeth (120) mesh with the elastic ratchet (410) of the clutch (400), and the direct ratchet teeth (130) are configured to mesh with the direct ratchet (330) when the direct ratchet (330) is extended from the ring gear (300).

The crankshaft (900) is configured to transmit driving force when the crank cover (100) rotates.

The sun gear part (900) includes a sun gear (910) and a ratchet gear part (920).

A sun gear tooth (911) is formed on the outer surface of the sun gear (910) and one area meshes with the eccentric gear (520). When the bicycle is driven, the sun gear (910) rotates. When in a high gear, it idles, and when in a low gear, it rotates together with the crank cover (100). In addition, a protruding sun gear tooth (912) is formed on one surface of the sun gear (910). The sun gear tooth (912) is formed in an overall ring shape and has an inclined portion that is inclined in one direction.

And the ratchet tooth portion (920) is configured to mesh with the sun gear teeth (912) of the sun gear (910), and a ratchet tooth that meshes with the sun gear teeth (912) of the sun gear (910) is formed on one side, and the other side is arranged on the crank cover (100).

The ratchet teeth of the sun gear (912) and the ratchet teeth portion (920) are formed with a unidirectional inclination so that when they mesh with each other, they can only rotate in one direction and cannot rotate in the reverse direction.

An annular mounting groove (913) is formed on the facing surface of the sun gear (910). A cover (940) is arranged between the facing surface of the sun gear (910) and the reduction gear portion (500), and a spring (930) is interposed in the mounting groove (913). One end of the spring (930) is fixed to the cover (940), and the other end is fixed to the sun gear (910). Accordingly, a force is applied to the sun gear (910) to press it toward the ratchet tooth portion (920) by the elastic restoring force of the spring (930), so that the engagement between the sun gear (910) and the ratchet tooth portion (920) is maintained.

At low speed, the direct ratchet (330) of the ring gear (300) is folded and does not mesh with the direct ratchet teeth (130) of the crank cover (100), so when the crank cover (100) rotates in the forward direction, there is no meshing between the ring gear (300) and the crank cover (100), so they do not directly rotate, and the sun gear (210) rotates in the forward direction around the coupling shaft (110) of the crank cover (100). The meshed reduction gear part (500) rotates due to the rotation of the sun gear (210), and the ring gear (300) is reduced and rotated through the reduction gear part (500). At this time, the sun gear (910) has a structure in which it is tightly meshed with the ratchet teeth part (920) by the spring (930).

When the user turns the pedal backwards to reverse the crank cover (100) during gear change, the sun gear (210) moves to the opposite side along the inclined surface of the ratchet tooth portion (920) due to the inclined direction of the sun gear teeth (912) and the ratchet tooth portion (920), and at this time, the spring (930) is compressed, and when it passes one tooth, the spring (930) is restored and the sun gear (910) is pressed against the ratchet tooth portion (920) again, and this process is repeated.

The direct ratchet (330) of the high-speed ring gear (300) is deployed by elasticity and engages with the direct ratchet teeth (130) of the crank cover (100). Therefore, when the user steps on the pedal to rotate the crank cover (100) clockwise, the crank cover (100) directly rotates the ring gear (300) at the same rotational speed. The reduction gear (500) rotates due to the rotation of the ring gear (300), and the sun gear (210) receives the rotational power of the ring gear (300) in reverse through the reduction gear (500) and idles at a faster rotational speed than the crank cover (100). In this case, similar to the gear change, the sun gear (910) moves to the opposite side of the ratchet tooth portion (920) due to the inclination direction of the sun gear teeth (912) and the ratchet tooth portion (920), and at this time, the spring (930) is compressed, and when one tooth is passed, the spring (930) is restored and the sun gear (910) is pressed against the ratchet tooth portion (920) again, and this process is repeated.

As described above, according to the present invention, a crank shifting device is provided which has a built-in transmission and shifts with only a single chainring, enables simplified configuration and lightweight construction, has excellent durability of continuously meshed ratchets/gears, and prevents stress from being concentrated, so that it can be used safely.

Any use of examples or exemplary terms (e.g., etc.) in the present invention is merely intended to illustrate the invention in detail and is not intended to limit the scope of the invention due to such examples or exemplary terms, unless otherwise defined by the claims. Furthermore, those skilled in the art will recognize that various modifications, combinations, and changes can be made according to design conditions and factors within the scope of the appended claims or their equivalents.

Therefore, the spirit of the present invention should not be limited to the embodiments described above, and not only the scope of the claims described below, but also all scopes equivalent to or equivalently modified from the scope of the claims are included in the scope of the spirit of the present invention.

1000, 2000: Bicycle Crank Shifter
100 : Crank cover 110 : Coupling shaft
111 : Home 120 : Clutch Ratchet Teeth
130: Direct ratchet gear 200, 900: Lead gear
210, 910: Sun gear 211: First gear
212: 2nd gear 211a, 911: Sun gear
212a: Sun gear ratchet teeth 220: Sun gear ratchet
300: Ring gear part 310: Ring gear part
320: Direct ratchet arrangement 330: Direct ratchet
331 : Operating lug 400 : Clutch
410: Elastic ratchet 420: Receiving part
430 : Support 500 : Reduction gear
510: Eccentric guide 511: Eccentric hole
520: Eccentric gear 600: Chainring housing
610: Base plate 611: First side wall
612: Second side wall 613: Position fixing projection
620: Chainring linkage 621: Arm
630 : sink 700 : bib holder
800: One-way bearing 920: Ratchet tooth part

Claims (10)

A ring gear portion having a direct ratchet arranged on the outside and gear teeth formed on the inner surface;
A crank cover having direct ratchet teeth formed on the inner surface thereof that selectively engage with the above direct ratchet and having a coupling shaft formed thereon;
A gear part mounted on the above-mentioned coupling shaft;
A reduction gear unit including an eccentric guide in which an eccentric hole is formed, and an eccentric gear coupled to the eccentric guide, one area of which meshes with the ring gear unit and another area of which meshes with the sun gear unit;
A chainring housing that rotates together with the above ring gear portion, has the above direct ratchet arranged on one side, and has a chainring connecting portion formed on the outer surface; and
A clutch part for selectively engaging the above direct ratchet with the above direct ratchet teeth is included;
The above mentioned fishing gear is,
A sun gear including a first gear having sun gear teeth formed on an outer surface thereof and meshing with the eccentric gear, and a second gear having sun gear ratchet teeth formed on one surface of the first gear and formed on an outer surface thereof;
A sun gear ratchet disposed on the crank cover and meshing with the sun gear ratchet teeth;
Bicycle crank gear. In the first paragraph,
The above-mentioned sun gear ratchet teeth have a slope along one direction.
Bicycle crank gear. In the second paragraph,
The above first gear and the above second gear are positioned at different heights along the thickness direction of the sun gear.
Bicycle crank gear. A ring gear portion having a direct ratchet arranged on the outside and gear teeth formed on the inner surface;
A crank cover having direct ratchet teeth formed on the inner surface thereof that selectively engage with the above direct ratchet and having a coupling shaft formed thereon;
A gear part mounted on the above-mentioned coupling shaft;
A reduction gear unit including an eccentric guide in which an eccentric hole is formed, and an eccentric gear coupled to the eccentric guide, one area of which meshes with the ring gear unit and another area of which meshes with the sun gear unit;
A chainring housing that rotates together with the above ring gear portion, has the above direct ratchet arranged on one side, and has a chainring connecting portion formed on the outer surface; and
A clutch for selectively engaging the direct ratchet with the direct ratchet teeth;
The above mentioned fishing gear is,
A sun gear having sun gear teeth formed on the outer surface to mesh with the eccentric gear and sun gear teeth formed on one surface;
A ratchet tooth portion having one side disposed on the crank cover and having ratchet teeth formed on the other side to mesh with the sun gear teeth;
Bicycle crank gear. In paragraph 4,
The above mentioned fishing gear is,
A cover placed between the above reduction gear section;
One side is fixed to the cover and includes an elastic member that allows the sun gear to be pressed against the ratchet tooth portion.
Bicycle crank gear. In paragraph 5,
In the above-mentioned sun gear, an annular fixing groove is formed,
The above elastic member is fixed at one end to the annular fixing groove, and the other end is fixed to the cover.
Bicycle crank gear. In any one of claims 1 to 6,
Further comprising a one-way bearing that prevents the chainring housing from rotating in the reverse direction when the crank cover rotates in the reverse direction;
Bicycle crank gear. In Article 7,
The outer surface of the above chainring housing has a protruding side wall formed in a circular shape.
It further includes a BB holder that can be interchangeably mounted on the above chainring housing;
The above one-way bearing is arranged between the side wall and the bib holder.
Bicycle crank gear. In Article 8,
The above direct ratchet is elastically supported along the radial direction of the above ring gear portion.
Bicycle crank gear. In Article 9,
An operating projection is formed on one side of the above direct ratchet,
The above clutch,
On the inner surface, a receiving portion for receiving the operating projection and a support member for supporting the operating projection are alternately formed at equal intervals along the circumferential direction, and on the outer surface, a plurality of elastic ratchets are formed at equal intervals and rotated to determine whether or not the direct ratchet is deployed.
Bicycle crank gear.

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