JP2000128059A - Gear shift device of bicycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gear shift device for bicycles, permitting a gear shift either while riding or stopping. SOLUTION: This gear shift device comprises multistage front gears 10 rotatably driven by cranks 4, multistage rear gears 25 mounted on a rear hub shaft, a front derailleur 15 arranged backward with respect to the driving rotational direction of the multiple front gears 10, and a rear derailleur 35 arranged afterward with respect to the driving rotational direction of the multistage rear gears 25. These members are configured such that, by means of reverse rotation of the cranks 4 with respect to the direction of driving rotation, a chain can be switched to be hanged on a selected front gear out of the multistage front gears 10 and to a selected rear gear out of the multistage rear gears 25.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-stage bicycle transmission which is shifted by operating a transmission cable.

[0002]

2. Description of the Related Art Conventionally, there is a bicycle having a multi-stage transmission to improve the running performance of the bicycle.

FIG. 6 shows an example of such a bicycle with a transmission. This bicycle 50 has a front transmission and a rear transmission. The front transmission is rotatably provided at the lower end of a seat tube 52 of a body frame 51 and is driven by a crank 53 to rotate. It has a multi-stage front gear 54 composed of different diameter front gears,
A front derailleur 55 for changing the chain 56 is provided in front of the multi-stage front gear 54 in the driving rotation direction (the direction of the arrow A in FIG. 6).

A rear transmission is mounted on a rear hub axle 57, and a chain 5 is mounted on a multi-stage front gear 54.
A rear derailleur 60 for rotating the chain 56 to the multi-stage rear gear 59 in front of the multi-stage rear gear 59 in the driving rotation direction. I have.

The front derailleur 55 is operated via a speed change cable 63 by a front speed change operation device 62 provided on a handle 61, and the rear derailleur 60 is operated by a rear speed change operation device 64.
5 to be operated.

[0006]

In such a conventional bicycle transmission, for example, when the multi-stage front gear 54 is shifted to a low-speed gear, the front derailleur 55 is operated by the front transmission operation device 62 to reduce the front diameter of the small-diameter front gear. Side, and guides the chain 56. With the rotation of the multi-stage front gear 54 (in the direction of the arrow A), the chain 56 is detached from the large-diameter front gear, and further rotation moves the chain 56 to the small-diameter front gear. The shift was being changed. Incidentally, also in the multi-stage rear gear 59,
The chain 56 is changed by driving rotation of the multi-stage front gear 54 in the direction of arrow A.

Therefore, when the running bicycle is temporarily stopped and restarted, immediately after the start, the bicycle starts at the same gear ratio as before, and a large crank driving force is required. Further, since the gear ratio is switched after the start, the running after the restart is slowed down, and there is a problem that running in a city area is particularly troublesome.

The present invention has been made in view of the above, and an object of the present invention is to provide a bicycle transmission that can perform a gear shift even during running and stopping.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object, and a bicycle transmission according to a first invention comprises a plurality of different-diameter front gears driven and rotated by a crank. A multi-stage front gear, a multi-stage rear gear comprising a plurality of different-diameter rear gears attached to a rear hub axle, a front derailleur for a front gear shift that acts on a chain wound around the multi-stage front gear and the multi-stage rear gear, A bicycle derailleur having a multi-stage front gear and a rear derailleur for shifting the rear gear by acting on a chain wound around the multi-stage rear gear, wherein the front derailleur is disposed rearward in the driving rotation direction of the multi-stage front gear. The rear derailleur is disposed rearward in the drive rotation direction of the multi-stage rear gear, and The reverse rotation of the driving rotation direction of said multi-stage becomes the front gear selected front gear and the multi Riyagia selected Riyagia is configured to be modified Cheng-seat, it is a bicycle speed change device according to claim.

According to a second aspect of the present invention, there is provided a bicycle transmission having a multi-stage front gear comprising a plurality of different-diameter front gears driven and rotated by a crank, a rear gear attached to a rear hub shaft, and winding around the multi-stage front gear and the rear gear. A front derailleur that acts on the hung chain and changes the speed,
Wherein the front derailleur is disposed rearward in the drive rotation direction of the multi-stage front gear, and the front derailleur is selected from the multi-stage front gear by rotation in the reverse direction of the drive rotation direction of the crank. The bicycle transmission is characterized in that it can be replaced with a chain.

According to a third aspect of the present invention, there is provided a bicycle transmission, wherein a front gear driven and rotated by a crank, a multi-stage rear gear comprising a plurality of different-diameter rear gears mounted on a rear hub axle, and wound around the front gear and the multi-stage rear gear. And a rear derailleur that acts on the chain to change gears, wherein the rear derailleur is disposed rearward in the driving rotation direction of the multi-stage rear gear, and rotates in a direction opposite to the driving rotation direction of the crank. , Whereby the chain gear can be changed to a rear gear selected from the multi-stage rear gear.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

In the figure, a bicycle denoted by reference numeral 1 has a crank 4, a handle 5, a front wheel 6, and a rear wheel 7 on a body frame 2.
And a multi-stage front gear 10 coaxially with the crank 4.
And a multi-stage rear gear 25 is mounted coaxially with the rear wheel 7.

The multi-stage front gear 10 is provided with a front derailleur 15 connected via a transmission cable 23 to a front transmission operation device 24 attached to the handle 5. The multi-stage rear gear 25 is provided with a rear derailleur 35 connected via a transmission cable 43 to a rear transmission operation device 44 attached to the handle 5. The chain 14 is wound between the multi-stage front gear 10 and the multi-stage rear gear 25.

In this embodiment, the multi-stage front gear 10 is composed of three sprockets having different numbers of teeth. The front gear 11, the front gear 12, and the front gear 13 are arranged in this order from the large-diameter sprocket, and are driven by the crank 4. It is configured to rotate.

The front derailleur 15 has a guide pulley 20 which can be displaced in the axial direction of the multi-stage front gear 10, and has a link base 16 which is pivotally supported by four connecting pins (not shown) and deforms into a parallelogram. Swing link 17,1
7. A parallelogram link mechanism having the support link 18 is formed.

A return spring 19 composed of a tension spring is interposed between the link base 16 attached to the front portion of the chain stay 3 and the support link 18, and a chain guide 22 is pivotally connected to the tip of the support link 18. Is being worn.
The chain guide 22 is urged to rotate in one direction by a torsion coil spring (not shown), and has a guide pulley 2 at one end.
0 is pivotally connected, and a tension pulley 21 is pivotally connected to the other end.

The front derailleur 15 is used to rotate the multi-stage front gear 10 in the direction of rotation (in the direction of arrow A in FIGS. 1 and 2).
At the rear, the guide pulley 20 is wound around the chain 14, and is elastically urged by the tension pulley 21 in a direction for applying tension to the chain 14. The chain 14 is displaced by the operation of the transmission cable 23 to displace the guide pulley 20 so that the chain 14
1, 12 and 13 are selectively exchanged.

In the present embodiment, the multi-stage rear gear 25 is composed of five sprockets having different numbers of teeth. Supported. The rear wheel 7 is configured as a freewheel.

The rear derailleur 35 has a multi-stage rear gear 25
A guide pulley 40 that can be displaced in the axial direction, and has a link base 36 that is pivotally supported by four connecting pins and deforms into a parallelogram, swinging links 37, 37, and a support link 38, and has a parallelogram shape. A link mechanism is formed. A return spring 39 made of a tension spring is interposed between the link base 36 attached to the rear portion of the chain stay 3 and the support link 38, and a guide pulley 40 is pivotally attached to the tip of the support link 38. .

In the rear derailleur 35, the chain 14 is wound around the guide pulley 40 behind the multi-stage rear gear 25 in the driving rotation direction (the direction of the arrow A in FIG. 4). , The chain 14 to the rear gears 26, 27, 28, 29,
30 is configured to be selectively replaced.

Next, the operation of the thus constructed bicycle will be described.

When the multi-stage front gear 10 and the multi-stage rear gear 25 are running with an arbitrary high gear ratio selected and stopped temporarily by a traffic signal or the like and restarted, while the bicycle 1 is stopped, the front derailleur 15 or Rear derailleur 35
Using the multi-stage front gear 10 or the multi-stage rear gear 2
A shift operation to a low gear ratio of 5 is performed.

For example, when the speed change cable 23 is extended, the support link 18 swings toward the link base 16 by the spring force of the return spring 19 of the front derailleur 15, and the guide pulley 20 presses the chain 14 laterally. Then, the chain 14 is displaced from a position facing the large diameter side of the front gears 11 to 13 to a position facing the small diameter side.

At the same time, when the crank 4 is rotated in the direction opposite to the driving rotation direction (arrow A), the chain 14 moves in the free direction in the direction opposite to arrow A, and is guided by the displaced guide pulley 20. To the front gear 12 (or 13) on the smaller diameter side.

By selecting the low-speed side gear of the multi-stage front gear 10, the vehicle can be restarted with a small crank driving force, the pedaling force can be reduced, and the inconvenience of shifting during running can be eliminated by shifting before starting. In addition, during the shifting operation, the crank 4 rotates freely with almost no load, so that the members constituting the front derailleur 15 do not require a hardening process or the like for providing wear resistance.

On the other hand, when the transmission cable 43 is extended, the support link 38 swings toward the link base 36 due to the spring force of the return spring 39 of the rear derailleur 35, and the guide pulley 40 presses the chain 14 laterally. Then, the chain 14 is displaced from a position facing the large diameter side of the rear gears 26 to 30 to a position facing the small diameter side.

At the same time, when the crank 4 is rotated in the direction opposite to the arrow A, the chain 14 is free and the arrow A
, And is guided by the displaced guide pulley 40 to be engaged with the selected rear gear 26 to 30.

At this time, the load condition of the crank 4, the reduction of the pedaling force at the time of restart, the shift before starting, and the like are controlled by the multi-stage front gear 1.
This is the same as the shift operation of 0 The shifting operation to the low speed side during traveling is the same as described above. Further, the shifting operation of the multi-stage front gear 10 and the multi-stage rear gear 25 may be used together.

When shifting from the low speed side to the high speed side gear while the bicycle 1 is traveling, the front derailleur 15 or the rear derailleur 35 performs a shift operation to the high gear ratio.

For example, when the speed change cable 23 is pulled, the support link 18 of the front derailleur 15 is returned by the return spring 19 due to the pulling force of the speed change cable 23.
Swings outward from the front position against the spring force of the chain, and the guide pulley 20 presses the chain 14 so that the chain 14
Is displaced from the small-diameter relative position of the front gears 11 to 13 to the large-diameter relative position.

At the same time, by rotating the crank 4 in the direction opposite to the arrow A, the chain 14 is moved to the large-diameter front gear 1.
By switching to 1 (or 12), a high gear ratio can be obtained.

When the transmission cable 43 is pulled, the support link 38 of the rear derailleur 35 swings inward from the front position inward of the vehicle body against the spring force of the return spring 39 due to the pulling force of the transmission cable 43. Then, the guide pulley 40 presses the chain 14 to move the chain 14
The rear gears 26 to 30 are displaced from the small-diameter relative position to the large-diameter relative position.

At the same time, the crank 4 is rotated in the direction opposite to the arrow A so that the chain 14
By switching to 30, a high gear ratio can be obtained. Also in shifting to this high gear ratio, the load on the crank 4 is minimal, and the shifting operations of the multi-stage front gear 10 and the multi-stage rear gear 25 may be used together.

Although the embodiments of the present invention have been described above, the shapes of the front derailleur and the rear derailleur can be changed within the scope of the technical concept of the present invention.

Further, the rear side may be a single rear gear, and a multi-stage front gear and a front derailleur alone may be used as a bicycle transmission.

Further, the front side may be a single front gear, and a multi-stage rear gear and a rear derailleur alone may be used as a bicycle transmission.

Further, a transmission having a multi-stage front gear and a front derailleur according to the present invention may be combined with a conventional transmission having a rear derailleur disposed forward of a multi-stage rear gear in the drive rotation direction.

Further, the transmission of the present invention comprising a multi-stage rear gear and a rear derailleur may be combined with a conventional transmission in which a front derailleur is disposed forward in the drive rotation direction of a multi-stage front gear.

[0040]

Since the bicycle transmission according to the present invention has the above-described structure, the bicycle can be shifted to an arbitrary gear ratio while the bicycle is running or stopped.

Therefore, when the bicycle equipped with the bicycle transmission according to the present invention is stopped and restarted, the low-speed gear ratio can be selected and started while the bicycle is stopped, so that the crank driving force can be reduced and Start acceleration can be performed promptly.

Further, since the speed can be shifted without applying a load to the derailleur at the time of the shifting operation, failures can be reduced, and processing for providing the components with abrasion resistance can be omitted, and the apparatus can be constructed at low cost. It has the effect of being able to.

[Brief description of the drawings]

FIG. 1 is a side view of a bicycle provided with a bicycle transmission according to the present invention.

FIG. 2 is a side view of the front transmission according to the present invention.

FIG. 3 is a plan view of FIG. 2;

FIG. 4 is a side view of the rear transmission according to the present invention.

FIG. 5 is a plan view of FIG. 4;

FIG. 6 is a side view of a bicycle provided with a conventional transmission.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bicycle 10 Multi-stage front gear 14 Chain 15 Front derailleur 25 Multi-stage rear gear 35 Rear derailleur

Claims (3)

[Claims] 1. A multi-stage front gear comprising a plurality of different-diameter front gears driven and rotated by a crank, a multi-stage rear gear comprising a plurality of different-diameter rear gears mounted on a rear hub shaft, and winding around the multi-stage front gear and the multi-stage rear gear. A transmission device for a bicycle, comprising: a front derailleur for shifting a front gear that acts on a chain that is hung, and a rear derailleur for shifting a gear that acts on a chain that is wound around the multi-stage front gear and a multi-stage rear gear. Wherein the front derailleur is disposed rearward in the drive rotation direction of the multi-stage front gear, and the rear derailleur is disposed rearward in the drive rotation direction of the multi-stage rear gear, in a direction opposite to the drive rotation direction of the crank. By rotation, the selected front gear of the multi-stage front gear and the multi-stage rear gear The bicycle transmission according to any one of claims 1 to 3, characterized in that the chain can be changed to a rear gear selected by the user. 2. A multi-stage front gear comprising a plurality of different-diameter front gears driven and rotated by a crank, a rear gear attached to a rear hub axle, and a chain acting on the multi-stage front gear and a chain wound around the rear gear to change gears. And a front derailleur, wherein the front derailleur is disposed rearward in the drive rotation direction of the multi-stage front gear; and A transmission for bicycles, which is configured to be capable of changing a chain to a selected front gear. 3. A front gear driven and rotated by a crank, a multi-stage rear gear comprising a plurality of different-diameter rear gears attached to a rear hub shaft, and a rear gear that acts on a chain wound around the front gear and the multi-stage rear gear. A bicycle derailleur, wherein the rear derailleur is disposed rearward in the drive rotation direction of the multi-stage rear gear, and selected rear gear of the multi-stage rear gear is driven by rotation in the reverse direction of the drive rotation direction of the crank. A transmission for a bicycle, characterized in that the transmission is changeable.