TWI460096B - Front deraillure system of bicycle - Google Patents

Description

Bicycle front shifting system

The present invention relates to a bicycle front shifting system.

Bicycles with multiple stages of gears at the front and rear are quite common. Generally, two or three gears are provided at the front, and five to ten gears are provided at the rear.

And having an external transmission in the front and rear portions, respectively, and configured to change the hanging gear by moving the externally mounted transmission toward the width direction of the bicycle, and selecting a desired gear ratio in the front derailleur, in the bicycle Two plates are provided substantially in parallel in the vehicle width direction, and the chains are pressed by the plates to move them.

Moreover, most recent bicycles have adopted an index system and are set to an optimum shift point by wire rope adjustment.

However, in the case of the front derailleur, since the chain is forcibly moved by moving toward the width direction of the bicycle, it is extremely difficult to smoothly shift the speed in the case where a moment is applied to the chain.

As shown in Fig. 1, the transmission 4 is provided on the front side with the outer plate 4a for replacing the chain 6 and the inner plate 4b. Although not shown, it is configured to be pulled by the shift lever and the cable. Open, so that the front derailleur moves toward the width direction of the bicycle, and the chain can be changed to the required gear, and more specifically, from the side of the small-diameter gear 2c toward the side of the large-diameter gear 2a (hereinafter referred to as upward Up shifting, in the case of changing the chain, by pulling the wire so that The outer panel 4a and the inner panel 4b are moved toward the large-diameter gear 2a side, and the chain is pressed by the inner panel 4b to move the chain toward the large-diameter gear 2a side to be attached to the desired gear.

Further, in the case where the chain is to be changed from the side of the large-diameter gear 2a toward the side of the small-diameter gear 2c (hereinafter referred to as a down shift), when the cable is opened, the restoration is built in the front derailleur. The spring 4c moves the outer plate 4a and the inner plate 4b toward the small-diameter gear 2c side, and is pressed by the outer plate 4a to move the chain toward the small-diameter gear 2c side to be attached to the desired gear.

The transmission 5 is provided on the rear side with the outer plate 5a and the inner plate 5b for replacing the chain 6, and although not shown, it is configured to pull and open the cable by the shift lever to make the rear The transmission moves toward the width direction of the bicycle, and the chain can be changed to the required gear. More specifically, in the case where the chain is to be changed from the side of the small-diameter gear 3d toward the side of the large-diameter gear 3a, the steel cable is used. The outer plate 5a and the inner plate 5b are pulled so as to move toward the large-diameter gear side, and the outer plate 5a presses the chain to move toward the large-diameter gear side to be attached to the desired gear.

Further, in the case where the chain is to be changed from the side of the large-diameter gear toward the side of the small-diameter gear, when the cable is opened, the return spring 5c built in the rear derailleur causes the outer plate 5a and the inner plate 5b to face the small diameter. The gear side moves, and the chain is moved toward the small-diameter gear side by the inner plate 5b to be pressed to the desired gear.

Depending on the condition of the road and the state of the physical force, etc., the external gearbox is operated by the shift lever as described above to select the desired gear ratio. However, in the case of shifting, the sprocket must be rotated, and at this time, no large load is applied to the chain. When there is a round, there is not much problem, but it can be shifted more smoothly, but in the case of climbing, etc. This causes a large load to be applied to the sprocket and the chain, which becomes very difficult to shift on the front side, especially when downshifting.

In addition, although the tooth profile of the recent sprocket has been modified to make it more versatile than before, its performance is still insufficient at large loads, and a higher performance prior shifting system is urgently required, but if it is too high When the performance is made into an extreme tooth shape, the contact between the chain and the gear, the contact between the chain and the outer or inner plate may occur due to the automatic shifting of the chain or the poor connection of the chain to the gear. Sounds and other various problems.

In order to explain this problem in more detail, the general tooth shape is formed into a shape as shown in Fig. 6, and in the case of downward shifting, the chain is tilted toward the small-diameter gear side by the off-guide tooth 2aac, and The chain is detached from the large-diameter gear by the disengagement 2abb, but in this case, as shown in Fig. 2, when the chain is wound around the large-diameter gear side 3a, 3b, 3c of the rear multi-stage gear, the design is The chain does not automatically shift downward from the large-diameter gear 2a or the medium-diameter gear 2b on the front side, or does not cause an abnormal sound due to poor attachment of the chain to the gear.

The off-guide tooth 2aac is applied with a chamfer of the dimension p toward the outer side in the width direction of the bicycle, and the chamfering of the dimension q is applied to the inner side of the bicycle in the width direction of the bicycle 2abb. A chamfer of dimension o is applied to the tooth 2acb to assist in tilting the chain away from the de-guide tooth 2aac.

In order to increase the shifting property of the downward shifting at a large load, as shown in FIG. 7, it can be cut into a shape like the disengagement tooth 2aaa to increase the inner side of the bicycle width direction of the decoupling 2aba. Chamfer, but as shown in the figure, if the chain is shaken due to large vibration or the like, if the chain is too extreme, In the state of the tilt shown in Fig. 2, even if the shifting operation is not performed, that is, even if the front derailleur is not moved, the chain is automatically shifted toward the small-diameter gear side, or the meshing with the gear is poor even if the shifting is not performed. The problem of producing abnormal sounds.

Further, in order to increase the shifting speed of the small-diameter gear 2c toward the intermediate-diameter gear 2b and the middle-diameter gear 2b toward the large-diameter gear 2a, as shown in Fig. 9, the small-diameter gear side surface of the large-diameter gear and the medium-diameter gear It is preferable to temporarily hold the protrusions 8a, 8b of the chain at the time of shifting, and to protrude as far as possible toward the small-diameter gear side, but if it is too over-exposed, when the chain is shaken due to vibration or the like, or the path of the chain In the state shown in Fig. 3, there is a case where the chain is in contact with the protruding portion to generate an abnormal sound.

Moreover, since most recent bicycles use a shifting system, and it is necessary to frequently shift gears at a determined position, it is more difficult to perform smooth shifting.

Further, in the case of the shifting system, although the optimum shifting point is set by the wire rope adjustment, as described above, when the torque is applied to the chain, it is difficult to obtain a smooth shifting speed in the set shifting point. Wire rope adjustment has also become a nuisance.

In addition, as described in Japanese Laid-Open Patent Publication No. Hei 6-305475, a modification of the front derailleur is proposed to improve the shifting performance. However, in this case, although the shifting property of the upward shifting is slightly improved, it is not expected to be large. There was a significant improvement in load, and there was no improvement in downshifting.

In a slightly more detailed description, the purpose of Japanese Patent Application Laid-Open No. Hei 6-305475 is to relax the interfering sound between the chain and the inner panel in the state shown in Fig. 2, and the shifting performance and the shifting of the upward shifting There is not much difference in knowing the structure. Because the contact sound with the chain is moderated, it can be over-shifted to improve the shifting performance. However, if this is done, the performance of the downward shifting will be extremely reduced, so the result is still impossible. Beyond the toothed disc, the shifting performance cannot be greatly improved compared with the conventional structure.

The present invention has been made in an effort to solve the above problems, and provides a bicycle front shifting system that can smoothly obtain a smooth shift even when a torque is applied to a chain, and can also easily perform a shift adjustment.

In order to achieve the above object, in the present invention, a gear other than the smallest diameter gear of the front sprocket composed of at least two or more gears is formed into a chain, which can be easily and automatically shifted downward, and is in the shape of the front derailleur. The auxiliary plate is assembled on top so that the chain does not automatically shift downward due to vibration or tilt.

More specifically, for example, in the case of a front sprocket composed of three gears, part or all of the maximum diameter gear and the intermediate diameter gear are designed such that the chain is automatically moved toward the chain due to vibration or tilt, even if the front derailleur is not moved. The small-diameter gear side shifting, or the meshing of the chain and the gear is deteriorated, and the shape of the abnormal sound is generated, and the plate on the inner side in the direction of the bicycle width of the front derailleur does not automatically shift toward the small-diameter gear side, The auxiliary board may be assembled in such a manner that the meshing of the chain and the gear is deteriorated to produce an abnormal sound, so that automatic shifting or abnormal sound of the chain is not generated.

In addition, the auxiliary plate is designed to be detachable, so that the effect of the auxiliary plate can be reduced due to wear, etc., and can be replaced with a new product, and the auxiliary plate can be formed by a sound absorbing material or the sound absorbing effect can be alleviated. Chain contact sound.

[Examples]

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Fig. 1 is a view showing a general bicycle having an externally mounted transmission before and after, and Fig. 2 is a view showing a state in which the chain is automatically shifted toward the small-diameter gear side or is difficult to smoothly wrap around the gear, and Fig. 3 is a view on the gear. FIG. 4 and FIG. 5 are explanatory views of the embodiment of the present invention, and FIG. 6 is an explanatory view of the tooth profile of the current gear, FIG. 7 and FIG. Fig. 9 is a diagram showing the shifting state of the gear from the middle diameter gear toward the large diameter gear, Fig. 10 is a state diagram of the chain held by the auxiliary plate, and Fig. 11 is a chain winding The state diagram of the front large diameter gear and the rear large diameter gear, the 12th figure is the state diagram of the chain winding around the front middle diameter gear and the rear large diameter gear.

In the present invention, in order to greatly improve the shifting property of the downward shifting, the disengagement guide teeth are formed into the shape of the teeth 2aaa as shown in Fig. 7, and the 2 to 3 pieces of the disengagement guide teeth are removed from the teeth. It is shaped like a tooth 2aba to make it easier for the chain to detach toward the small-diameter gear side.

The detachment guide tooth 2aaa is used to cut the conventional tooth 2aac, and the purpose thereof is to make the chain easy to tilt toward the smaller diameter gear side, and to provide the inner side of the bicycle width direction of the bicycle 2abb from the tooth removal 2aba. The chamfer q has a larger chamfering t, the purpose of which is to disengage even when the chain is only slightly inclined, and the off-guide auxiliary tooth 2aca is provided with a larger chamfer o than the outer side of the bicycle 2c in the width direction of the bicycle 2acb. The chamfer r is intended to make the inclination of the chain larger by the disengagement guiding teeth 2aaa.

In another embodiment, as shown in the figure 8 of the disengagement guide tooth 2aab, the cutting is not performed as the off-guide tooth 2aaa, and the chamfer of the outer side of the bicycle is made to be smaller than the conventional one. The chamfering s of the chamfering p of the decoupling tooth 2aac is larger, so that the chain is easily inclined toward the smaller diameter gear side.

The gears other than the smallest diameter gears of the front sprocket formed by at least two gears are provided with such a shape of the disengaging guide teeth, the disengagement teeth, and the disengagement guide teeth, but in this state, the chain is When tilting as shown in Fig. 2, even if the front derailleur is not operated, the chain will automatically shift to the small-diameter gear side, or abnormal sound will be generated due to the chain-to-gear failure.

On the other hand, in the state of Fig. 2, the tooth shape of the disengagement guide tooth, the disengagement tooth, and the disengagement guide auxiliary tooth is set such that the chain automatically shifts to the small-diameter gear side or generates an abnormal sound.

On the other hand, on the inner panel 4b of the front derailleur 4, the auxiliary plate 7 is integrally or detachably provided, and the positional relationship between the auxiliary plate and the inner panel in the bicycle width direction is as shown in Fig. 2 At this time, it is set such that the inner panel 4b is not in direct contact with the chain and is first contacted by the auxiliary panel. This is because the inner plate is generally made of a metal having a high rigidity, so that when the chain contacts the inner plate, a metal tone with an uncomfortable feeling is generated, so that the inner plate does not directly contact the chain.

In more detail, since the chain is wound around the large diameter gear of the sprocket and the largest diameter gear of the rear free flywheel, the most accessible part of the chain and the inner plate 4b is as shown in Fig. 11, at point p1. In the vicinity, the surface 7a of the auxiliary plate is disposed at a position closer to the chain than the point p1 at the rear portion, and because the chain is wound around the largest diameter gear of the sprocket and the rear free flywheel , the most accessible part of the chain and the inner panel 4b As shown in Fig. 12, in the vicinity of the point p2, the surface 7b of the auxiliary plate is disposed at a position in front of the chain contact with the chain earlier than the point p2.

In the case where the sprocket and the front derailleur configured as described above are used, the following effects will be described.

According to the embodiment, when the off-guide tooth, the off-tooth removal, and the off-guide auxiliary tooth are formed into an extreme shape, the downward shift can be greatly improved, but the chain is in the state as shown in FIG. Without the front derailleur being actuated, it will automatically shift downwards, or even if it does not shift downwards, the chain will still behave worse than the gear, which is because the chain is larger than the usual path. The side of the small-diameter gear is inclined to the side of the smaller-diameter gear.

However, in the transmission prior to the present invention, as in the state of Fig. 2, as shown in Fig. 10, since the auxiliary plate is placed in contact with the chain or has a small gap, even if the chain is intended to be smaller than the usual path When the radial gear side is still held by the auxiliary plate, the normal path can be maintained without automatically shifting downward, or the chain-to-gear winding is deteriorated to generate abnormal sound.

At this time, although the contact sound is generated by the contact of the chain with the auxiliary plate, the auxiliary plate is formed of a material which can relax the contact sound with the chain, such as a resin, etc., in general, and therefore does not cause a feeling of discomfort. Further, if a resin material having a silencing effect or a damper having a silencing effect is interposed between the inner panel and the auxiliary panel, the contact sound can be further alleviated.

In the present embodiment, the auxiliary plate 7 is attached to the inner panel by the pin 9, but the auxiliary plate 7 and the inner panel 4b may be integrally formed, and the surface 7a and the surface 7b may be attached or adhered with a silencing effect. Material, or may be silenced The material is formed to form the entire inner panel 4b.

In the case of downshifting from the state of Fig. 2, since the degree of downward shifting is automatically performed in accordance with the state without being held by the auxiliary plate, the disengagement tooth, the dislocation tooth, and the disengagement guidance are set. Since the shape of the teeth is such that when the front derailleur is moved toward the small-diameter gear side, the chain is not held by the auxiliary plate, and the chain is instantaneously hung on the small-diameter gear side.

In addition, even when the chain is wound around the gear 3d of the rear freewheel, the shape of the disengagement tooth, the dislocation tooth, and the disengagement auxiliary tooth can be easily separated from the shape of the chain, so that the chain can be greatly improved. The performance of downshifting.

In the upward shift, in the case of the conventional configuration, for example, when the shift from the middle diameter gear to the large diameter gear, the front derailleur is moved toward the large diameter gear side, and the chain is pressed toward the large diameter gear side by the inner plate 4b. Then, as shown in Fig. 9, the chain is lifted by the projection 8a to move the chain to the large-diameter gear side, but as described above, since the shifting is difficult when a large load is applied, the projection 8a is made The side of the small-diameter gear is more prominent, but as shown in Fig. 3, when the chain is tilted, the protruding height is limited because the chain is in contact with the protrusion, and the protruding height is limited. In this case, since the inner plate 4b of the front derailleur is in contact with the chain after the shift is completed, an abnormal sound is generated, so that the overtaking of the sprocket cannot be performed. As a result, sufficient shift performance cannot be obtained.

However, in the present invention, the auxiliary plate 7 is brought into contact earlier than the contact between the inner plate and the chain. Therefore, even after shifting beyond the toothed disk, an abnormal sound such as a metal sound is not generated, so that it can be sufficiently Beyond the toothed disc, the result, Even if a large load is applied, the shifting performance from the small-diameter gear side toward the large-diameter gear side can be greatly improved.

As described above, in the present invention, since the tooth shape of the large-diameter gear and the medium-diameter gear is made into a shape that is easy to automatically shift, the shifting performance of the downward shifting is greatly improved, so even if it slightly exceeds the toothed disc, it will not The shifting performance of the downshift is reduced, and as a result, the shifting performance of the upshift and the downshift can be greatly improved at the same time.

Further, the present invention is not limited to the embodiment. In the front sprocket, in the case where the chain is inclined with respect to the gear, the automatic shifting tooth shape can be made, and in the case of the front derailleur, when the chain is inclined with respect to the gear, When the chain is in contact with the auxiliary board, it is not necessary to produce a contact sound having an uncomfortable feeling.

(effect of the invention)

In the conventional shifting system, although the front sprocket-shaped tooth profile or the front derailleur is modified to improve the shifting performance, if the shifting performance is to be extremely improved, automatic shifting or abnormal sound is generated, so the improvement is improved. There is still a limit. The current situation is that sufficient shifting performance cannot be obtained at high load. In addition, by the generalization of the shifting system, it is very troublesome to adjust at any point that can satisfy either the upshift and the downshift, and the result is very troublesome. I have to compromise on some level of performance.

The present invention is to solve the problem of the current situation in one place, by making the tooth shape of the gear other than the small-diameter gear of the front sprocket into an automatically shiftable shape, and simultaneously setting an auxiliary plate in the front derailleur to keep the chain from being Automatic shifting, which greatly improves the shifting performance of the downshift at high load, and can be adjusted by setting the auxiliary plate and greatly improving the shifting performance of the downshift. Beyond the sprocket wheel, the shifting performance of the downshift can be greatly improved, and by using the sprocket and the front derailleur in combination with the present invention, a huge effect that has not been achieved so far can be obtained.

2aaa‧‧‧Off guiding tooth

2aab‧‧‧Disengagement guide teeth

2aac‧‧‧Disengagement guide teeth

2aba‧‧‧De-toothing

2abb‧‧‧ De-toothing

2aca‧‧‧Off guidance auxiliary teeth

2acb‧‧‧Off guidance auxiliary teeth

Q‧‧‧Chamfering

T‧‧‧Chamfer

O‧‧‧Chamfer

R‧‧‧Chamfer

P‧‧‧Chamfering

S‧‧‧Chamfer

2a‧‧‧ Large diameter gear

2b‧‧‧Medium diameter gear

2c‧‧‧ small diameter gear

3a, 3b, 3c‧‧‧ large diameter gear

3d‧‧‧ small diameter gear

4‧‧‧ Front derailleur

4a‧‧‧outer board

4b‧‧‧ inner board

4c‧‧‧Recovery spring

5‧‧‧ Rear derailleur

5a‧‧‧outer board

5b‧‧‧ inner board

5c‧‧‧Recovery spring

6‧‧‧Chapter

7‧‧‧Auxiliary board

7a, 7b‧‧‧ face of the auxiliary board

8a, 8b‧‧‧ prominence

9‧‧ ‧ sales

Fig. 1 is a view showing a general bicycle having an exterior transmission before and after.

Fig. 2 is a view showing a state in which the chain is automatically shifted toward the small-diameter gear side or is difficult to smoothly wrap around the gear.

Fig. 3 is a view showing a state in which a shifting projection provided on a gear and a chain are likely to generate a contact sound.

Fig. 4 is an explanatory view showing an embodiment of the present invention.

Fig. 5 is an explanatory view showing an embodiment of the present invention.

Fig. 6 is an explanatory view of the tooth profile of the current gear. Fig. 7 is an explanatory view of the tooth profile of the gear which is easy to automatically shift.

Fig. 8 is an explanatory view of the tooth profile of the gear which is easy to automatically shift.

Fig. 9 is a diagram showing the shifting state of the self-diameter gear toward the large-diameter gear.

Figure 10 is a diagram showing the state in which the chain is held by the auxiliary plate.

Figure 11 is a state diagram of the chain wrapped around the front large diameter gear and the rear large diameter gear.

Figure 12 is a state diagram of the chain wrapped around the front and rear large diameter gears.

2aaa‧‧‧Off guiding tooth

2aca‧‧‧Off guidance auxiliary teeth

2aba‧‧‧De-toothing

2a‧‧‧ Large diameter gear

2b‧‧‧Medium diameter gear

2c‧‧‧ small diameter gear

4‧‧‧ Front derailleur

4a‧‧‧outer board

4b‧‧‧ inner board

4c‧‧‧Recovery spring

6‧‧‧Chapter

7‧‧‧Auxiliary board

7a, 7b‧‧‧ face of the auxiliary board

Claims (4)

A front shifting system for a bicycle, characterized in that a shape of a disengagement tooth of a gear other than a minimum diameter gear of a front sprocket composed of at least two or more gears is set as a truncated head type, and The chamfering of the dislocation and disengagement auxiliary teeth are respectively set to a specific chamfer which can cause the chain to fall toward the small diameter gear side; and an auxiliary plate is disposed inside the inner plate of the front derailleur, wherein the inner plate and the chain are not Direct contact, and the auxiliary plate contacts the chain, or the auxiliary plate and the chain have a slight gap, and the auxiliary plate contacts the chain first than the inner plate, so that the chain does not automatically move toward vibration or tilt The lower plate is formed; and the auxiliary plate is formed of a material that can relax the contact sound with the chain than a general metal material. The bicycle front shifting system of claim 1, wherein the auxiliary plate is disposed before the chain is wound by a maximum free or maximum diameter gear of the rear free flywheel or the cassette cog. In the case of two gears, the state in which the gear is tilted and vibrated, and the gear is to be automatically shifted downward, or when the gear is to be down-shifted and cannot be smoothly wound around the gear, it comes into contact with the chain. The bicycle front shifting system of claim 1, wherein the auxiliary plate is configured to be detachable. The bicycle front shifting system of claim 1, wherein the auxiliary plate is formed of a sound absorbing material.