JPS6232158Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention is a rear derailleur for a bicycle, more specifically, a chain guided by a chain guide equipped with a guide pulley, a tension pulley, and a plate that supports these pulleys. This relates to a rear dayrailleur that changes gears by switching to the rear derailleur.

Generally, this type of derailleur has a derailleur main body formed by a link mechanism mainly consisting of a support member, a pair of link members, and a movable member, and the chain guide is pivotally attached to the movable member of the derailleur main body. The front sprocket is placed axially outward of the high-speed sprocket of a multi-stage sprocket that is attached to the rear wheel hub of a bicycle, and a frame that supports the rear wheel is attached via the support member, and the front sprocket is attached to a crank with pedals. A chain that is hung from the gear to the multi-stage sprocket is hung from the tension pulley to the guide pulley, and the movable member is pulled by an operation wire against the force of a return spring provided on the derailleur main body. The chain is then moved to the low-speed sprocket with the maximum number of teeth, and by the restoring action of the spring to the high-speed sprocket with the minimum number of teeth, so that the chain is replaced with one sprocket in the multi-stage sprocket.

By the way, in this type of dayrailer, even if the chain is not driven by the pedal depression,
A power accumulating mechanism is provided so that a gear shift operation can be performed in advance using an operating lever, and by moving the chain by driving a pedal, the chain can be changed to a gear position of the operating lever that has been operated in advance.

Therefore, when changing gears by changing the chain, if the pedal is depressed in the forward rotation direction and the vehicle is traveling forward, the chain can be moved smoothly and the chain can be changed without any problem.
When the chain is hung on the high-speed sprocket, the operating wire is pulled and the chain guide is previously operated from the high-speed sprocket position to the low-speed sprocket, and the pedal is inadvertently depressed. Alternatively, if the bicycle is carelessly backed up and the multi-stage sprocket is reversely rotated, the chain comes into contact with the derailleur main body side plate of the chain guide and is lifted in the direction away from the guide pulley, and eventually the plate The derailleur gets over the gap and falls outside of the plate, and this fallen part gets caught in the gap and does not move.As a result, an excessive force is applied to the derailleur, resulting in damage to the derailleur.

That is, when the chain is not pedal driven,
When the operating wire is pulled with the chain hanging from the high-speed sprocket, the portion of the chain hanging from each of the pulleys will move along with the chain guide within the range that allows the chain to move in the axial direction. While moving to the low speed sprocket side,
Since the part of the chain that hangs onto the high-speed sprocket tends to remain on the high-speed sprocket, the chain tilts significantly between the high-speed sprocket and the guide pulley. Therefore, if the multi-stage sprocket is rotated in the reverse direction by depressing the pedal in the opposite direction or by reversing the bicycle, the chain will move backward in an inclined state. However, the chain tilted between the high-speed sprocket and the guide pulley is pressed against the side surface of the tooth tip of the high-speed sprocket and the side surface of the derailleur body side plate of the chain guide, and is not engaged with the high-speed sprocket. At the same time that the disengagement becomes difficult, the flow of the chain to the guide pulley becomes poor, and as a result, the chain is lifted forward in the direction of rotation of the sprocket.

That is, as shown in FIG. 7, the outer peripheral edge G of the derailleur main body side plate P has an arc shape along the outer peripheral edge of the guide pulley GP. tries to enter the outer peripheral edge of the plate P from the tangential direction, but at this time, since the chain is pressed against the side surface of the tip of the high-speed sprocket and the side surface of the plate P, The chain C is lifted radially outward from a predetermined position as shown in FIG. 7 while sliding on the outer peripheral edge G without smoothly flowing to the guide pulley GP.

When the chain tension increases due to the lifting of the chain C, it is forcibly pulled toward the guide pulley, but at this time, the chain C crosses over the outer peripheral edge G and separates from the guide pulley GP. The detached chain C gets caught in the derailleur body side, and this biting prevents the chain from moving backwards from the guide pulley GP to the tension pulley, and the part of the chain that extends from the tension pulley to the front gear The tension caused by the reverse rotation of the front gear puts unreasonable force on the derailleur.

The present invention was devised in view of the above points, and the purpose is that when the chain is hung on the high speed side sprocket, when the control lever is operated to the low speed side,
To enable a chain to be moved in the reverse direction without falling off a plate of a chain guide even when the pedals are depressed backwards or the bicycle is moved backwards.

Therefore, the configuration of the present invention is a rear derailleur in which a chain guided by a chain guide device including a guide pulley, a tension pulley, and a plate is replaced with one of the multi-stage sprockets of a bicycle to change speed. A plate on the derailleur main body side plate of the guide device, which protrudes outward in the radial direction of the guide pulley from the outer periphery of the inlet passage portion of the plate when the chain moves backward from the multi-stage sprocket to the guide pulley, and the tip in the protruding direction. A suppressing part is provided whose side is inclined toward the center in the axial direction of the guide pulley to suppress lifting of the chain from the outer peripheral edge when the chain is moved in reverse, and the chain is moved in the reverse direction without being separated from the plate. I made it possible.

An embodiment of the derailleur of the present invention will be described below with reference to the drawings.

The illustrated derailleur includes a support member 3 that is pivotally supported via a horizontal shaft 2 to a bracket 1 for mounting on the rear wheel of a bicycle, and a pair of link members 4 attached to the support member 3.
A chain guide 6 is swingably supported on the movable member 5 of the derailleur main body A, which is comprised of a movable member 5 that is swingably connected to the derailleur main body A via a movable member 5.

This chain guide tool 6 includes the guide pulley 61, tension pulley 62, and left plate 6.
3 and a right plate 64, the right plate 64 was supported on the movable member 5 by caulking, and the left plate 63 was swingably supported on the movable member 5 via a pivot shaft 7. Something,
Each pulley 61, 62 of this chain guide tool 6
Of these, the guide pulley 61 is arranged on the side closer to the multi-stage sprocket S, the tension pulley 62 is arranged on the side away from the multi-stage sprocket S, and the chain is hung on each of these pulleys 61 and 62. Then, by pulling the operating wire W, the movable member 5 is moved to the low-speed sprocket with the maximum number of teeth against the force of a return spring (not shown).
Move it to the S ₂ side, and then move it to the S ₁ side of the high-speed sprocket with the minimum number of teeth by the restoring action of this spring.
The chain C suspended on the guide pulley 61 and tension pulley 62 is replaced with one sprocket of the multi-stage sprocket S. Further, a tension spring 8 is interposed between the chain guide tool 6 and the movable member 5 to bias the chain guide tool 6 clockwise in FIG. 1 and apply tension to the chain. There is.

In the rear derailleur constructed as described above, the chain C is connected to the guide pulley 61 from the multistage sprocket S to the right plate 64 on the derailleur main body side of the chain guide 6.
The guide pulley 61 projects outward in the radial direction from the outer periphery of the inlet passage portion of the plate 64 when the chain C moves in the reverse direction, in other words, the outlet passage portion when the chain C moves in the forward direction. A suppressing portion 65 is provided whose front end side is inclined toward the center in the axial direction of the guide pulley 61 to suppress lifting of the chain C from the outer peripheral edge when the chain C moves backward.

This suppressing portion 65 is formed by cutting out, for example, an outer circumferential edge formed concentrically with the guide pulley 61, and the suppressing portion 65 is formed by cutting out the outer circumferential edge that is formed concentrically with the guide pulley 61. On the other hand, it will protrude outward in the radial direction, and
As shown in FIG. 5, the tip side in the protruding direction is inclined toward the contact side with the chain C, that is, toward the axial center of the guide pulley 61, and the chain C is connected to the high speed sprocket _S1 . When moving from the high-speed sprocket S ₁ to the guide pulley 61 in an inclined manner between the chain C and the guide pulley 61 that has been displaced toward the low-speed sprocket S ₂ , the side surface of the chain C comes into contact with the suppressing portion 65 . , this suppressing portion 65 is formed such that it protrudes radially outward from the outer peripheral edge, and the distal end side in the protruding direction is inclined toward the axial center side of the guide pulley 61 to prevent misalignment of the chain with respect to the right plate 64. This suppresses the displacement of the contact position of the chain C on the right plate 64, and allows the chain moving from the high-speed sprocket S toward the guide pulley 61 to rotate in the opposite rotation direction of the high-speed sprocket S. This is to prevent the chain C from being lifted forward and detached from the right plate 64, and to move the chain C from the guide pulley 61 to the tension pulley 62 in the restrained state.

In the illustrated derailleur, a pair of pins 9 that connect the link member 4 to the support member 3 and a pair of pins 10 that connect the movable member 5 to the link member 4 are aligned with the axis of the multistage sprocket S. When replacing the chain, the chain is tilted with respect to a plane perpendicular to the
The chain guide 6 is moved parallel to the axis of the multi-stage sprocket S, and at the same time is moved in the radial direction of the multi-stage sprocket S in a plane perpendicular to the axis.

Moreover, the right plate 64 of the chain guide tool 6 is
First support part 64b that supports guide pulley 61
and a second support portion 64c that supports the tension pulley 62, but they may be integrated.

The present invention is constructed as described above, and in the state shown in _FIG . It is hung on sprocket _S1 . However, when the operating wire W is pulled in advance from the levered state, the part of the chain C that is hooked onto the guide pulley 61 and the tension pulley 62 is moved within the range that allows the chain to move in the axial direction. The chain C moves to the low-speed sprocket _S2 side together with the tool 6, whereas the part of the chain C that hangs onto the high-speed sprocket _S1 tends to remain on the high-speed sprocket _S1 . It is largely inclined between the sprocket S ₁ and the guide pulley 61, and this inclined portion is the suppressing portion 65 of the right plate 64.
At this time, if the multi-stage sprocket S is rotated in the opposite direction by depressing the pedal in the opposite direction or by backing up the bicycle, the chain C will be in a state where the inclined part is in contact with the restraining part 65. Reverse movement from high speed sprocket _S1 to guide pulley 61. During this reverse movement, the suppressing portion 65 suppresses the displacement of the contact position of the chain with the right plate 64, preventing it from being lifted forward in the reverse rotation direction of the high-speed sprocket _S1 , and Due to the pressing force caused by the movement of the chain guide 6 toward the low-speed sprocket S ₂ , the contact resistance between the inner plate and the outer plate at the inclined portion increases, and this inclined portion becomes rigid, and in this rigid state, the guide pulley 61 It is sent from there toward the tension pulley 62. As a result, separation of the chain from the right plate 64 can be prevented.

As described above, the present invention provides a derailleur main body side plate in a chain guide device equipped with a guide pulley, a tension pulley, and a plate, so that the derailleur main body side plate is provided outside the inlet passage portion of the plate when the chain moves backward from the multi-stage sprocket to the guide pulley. It protrudes outward in the radial direction of the guide pulley from the periphery, and its tip side in the protruding direction is inclined toward the center in the axial direction of the guide pulley to prevent the chain from being lifted from the outer periphery when the chain moves backward. Since a restraining part is provided, when the chain is hung on the high-speed sprocket of a multi-stage sprocket, it is difficult to press the pedal in the opposite direction or back up the bicycle with the operating lever moved to the low-speed sprocket in advance. Even in such a case, it is possible to suppress the displacement of the contact position of the chain on the plate and prevent the chain from being lifted forward in the reverse rotational direction of the high-speed sprocket, thereby preventing the chain from separating from the plate. It can be moved towards the tension pulley, eliminating the problem of derailleur damage.

[Brief explanation of the drawing]

Figure 1 is a front view of the derailleur of the present invention attached to a bicycle frame together with a multi-stage sprocket, Figure 2 is an enlarged cross-sectional view of the support part of the chain guide to the movable member, and Figure 3 is only the plate of the chain guide. , FIG. 4 is a rear view, FIG. 5 is a sectional view taken along the line V-V in FIG. It is an explanatory view showing the relationship between a plate and a pulley in a conventional chain guide tool. 6...Chain guide, 61...Guide pulley, 62...Tension pulley, 64...Plate, 65...Suppression part, C...Chain, S...Multi-stage sprocket.

Claims (1)

[Scope of utility model registration request] A rear derailleur that changes speed by replacing a chain guided by a chain guide device including a guide pulley, a tension pulley, and a plate with one of the multi-stage sprockets of a bicycle, the chain guide device having a plate on the side of the derailleur body. , when the chain moves backward from the multi-stage sprocket to the guide pulley, the chain protrudes radially outward from the outer peripheral edge of the inlet passage portion of the plate, and the distal end side in the protruding direction is at the axial center of the guide pulley. A rear derailleur for a bicycle, characterized in that a restraining portion is provided that slopes to the side and restrains the chain from being lifted from the outer peripheral edge when the chain moves in reverse.