JPH0356236B2 - - Google Patents

Description

TECHNICAL FIELD The present invention relates to a bicycle chain gear, and more particularly to a bicycle chain gear that constitutes a multi-stage chain gear device and constitutes a transmission together with a derailleur.

Prior Art Generally, in a bicycle, a multi-stage chain gear device configured by combining two or more chain gears with different numbers of teeth is attached to the rear wheel hub or crank.
A chain hung from one chain gear in this multi-stage chain gear device is displaced in the axial direction of the chain gear device by a derailleur, and the chain is replaced by another chain gear, and the pedal depression force is adjusted to a predetermined gear ratio. It is created as if it were being transmitted to a ring.

However, conventional bicycle chain gears are formed by punching a single metal plate into a circular shape or by casting, so that they are inseparable and have a predetermined rigidity. Therefore, when changing the chain using the derailleur, if the chain is displaced by the derailleur and the chain is changed from, for example, a small-diameter chain gear with a small number of teeth to a large-diameter chain gear with a large number of teeth, the chain is moved by the derailleur to a large-diameter chain gear. Even if the chain is displaced to the side, the outer surface of the link plate in the chain interferes with the inner surface of the tooth tip of the large-diameter chain gear and is received by the large-diameter chain gear. Overshift to the lateral side,
If the chain is not strongly pressed against the side of the large-diameter chain gear, the chain will not be picked up by the teeth of the large-diameter chain gear, and therefore the chain cannot be smoothly transferred to the teeth of the large-diameter chain gear, and the chain There was a delay in changing to a larger diameter chain gear. Furthermore, when changing the chain from the large-diameter chain gear to the small-diameter chain gear, the side edge of the link plate in the chain is strongly pressed against the outer surface of the tooth portion of the large-diameter chain gear, and the chain at this pressed portion is attached to the small-diameter chain gear. Strongly gouged by the side,
The chain at this gouged portion is lifted to the top side of the teeth of the large-diameter chain gear and is removed from the teeth of the large-diameter chain gear, but the chain is strongly pressed against the outer surface of the teeth of the large-diameter chain gear. Because of the large surface pressure at the gouged portion, it was difficult for the chain to come off the teeth of the large-diameter chain gear, and there was a corresponding delay in replacing the chain with the small-diameter chain gear.

OBJECT OF THE INVENTION An object of the present invention is to provide a gear main body with a split groove and a flexible portion so that the tooth portion of the gear main body can be displaced in the axial direction, and to use the derailleur to press the chain in the axial direction. By displacing the tooth portion that can be displaced by the groove and the bending portion, the chain that is displaced from the small diameter chain gear to the large diameter chain gear can be easily brought to the outside of the tooth tip of the large diameter chain gear, and the chain can be moved from the large diameter chain gear to the small diameter chain gear. The object of the present invention is to reduce the surface pressure of gouging at the part of the chain that is displaced from the large-diameter chain gear teeth, and to further improve speed changeability.

Structure of the Invention Accordingly, the structure of the present invention is a bicycle chain gear constituting a multi-stage chain gear device, in which a gear body having a large number of teeth is provided with a split groove extending toward the center from the tooth portion of the gear body. At the same time, a flexible portion of a predetermined length is provided on the front side of the split groove in the driving rotation direction of the gear body to displace the tooth portion in the axial direction of the gear body, and utilizes the pressure of the chain in the axial direction by the derailleur. and by displacing the flexible tooth part that is movable by the split groove and the flexible part in the direction of the chain gear to be replaced, so that the chain can be easily moved toward the outer side of the tooth tip of the large diameter chain gear,
Moreover, it was made so that it could easily come off from the teeth of the large diameter sprocket.

Embodiment Next, an embodiment of the chain gear of the present invention will be described based on the drawings.

What is shown in FIG. 1 is a bicycle transmission in which the present invention is applied to a front side multi-stage chain gear device FG.
The rear multi-stage chain gear device RG, which has a chain C suspended between it and the front multi-stage chain gear device FG, is composed of five chain gears 3 to 7 with different numbers of teeth. .
And the front side multi-stage chain gear device FG
Front derailleur FD is installed, and rear multi-stage chain gear device RG is equipped with rear derailleur RD.
are mounted in correspondence with each other, and a ten-speed shift can be performed by combining the chain gears 1, 2, and 3 to 7 in each of the chain gear devices FG and RG.

In addition, as is known, the front trailer FD has the following features:
A chain guide CG is provided that moves in the axial direction of the front side multi-stage chain gear device FG, and by moving the chain guide CG in the axial direction, the chain C is replaced with one of the chain gears 1 and 2. In addition, the rear derailleur RD is provided with a hanging frame Y having a pair of pulleys P ₁ and R ₂ , and the hanging frame Y is connected to the rear side multi-stage chain gear device RG in the axial direction. By moving, the chain C is replaced with one of the chain gears 3 to 7.

Next, an embodiment of the chain gear of the present invention applied to the transmission configured as described above will be described based on FIGS. 2 to 4.

What is shown in FIGS. 2 to 4 is a large-diameter chain gear 1 constituting a front side multi-stage chain gear device FG.As shown in FIG. , the gear body 1
A split groove 13 extending from the tooth portion 12 of 0 toward the center is provided, and the gear main body 10 is provided from the split groove 13.
To the front side in the drive rotation direction (arrow x direction in Figure 2),
A flexible portion 14 having a predetermined length is provided to displace the tooth portion 12 in the axial direction of the gear body 10.

The gear main body 10 is formed by punching a flexible metal plate such as a steel plate into, for example, a circular annular shape. The gear body 10 may be formed of a material other than a metal plate, may be formed into an oval shape, or may be formed into a disk shape with a through hole in the center. Of course, this is a good thing.

Further, the split groove 13 is provided from the bottom of the tooth portion toward the center of the gear body 10, and for example, as shown in FIG. When a plurality of mounting pieces 15 are provided that protrude toward the center, and decorative holes 16 are provided in the forming portions of these mounting pieces 15, the decorative holes 16 are provided from the bottom of the tooth to the decorative holes 16. If the decorative hole 16 is not provided, it is provided extending from the bottom of the tooth to the inner circumferential surface of the gear body 10.

Further, the grooves 13 may be provided linearly in the radial direction, but are preferably formed in a hook shape in the radial direction and the circumferential direction as shown in FIG.

By doing so, the radial deflection of the flexible portion 14 formed by the groove 13 can be restricted.

Further, the grooves may be inclined in the circumferential direction of the gear body 10, for example. Further, the gear main body 10 is formed in a disc shape, or the length between the outer circumferential surface and the inner circumferential surface of the gear main body 10 is relatively long, and the grooves 13 are oriented in the radial direction. If it is difficult to displace the tooth portion in the axial direction by just forming the groove, the groove 13 may be formed into a hook shape in the radial direction and the circumferential direction, or the groove 13 may be formed in a hook shape in the radial direction and the circumferential direction. It is formed in a step-like shape facing in the direction. or,
The split groove 13 may be provided from the tip of the tooth 11 or from the intermediate portion between the tip and the bottom of the tooth.

Further, the flexible portion 14 provides flexibility by utilizing the elasticity of the material forming the gear body 10.

Incidentally, the chain gear shown in the drawings has the flexible portion 1 near the split groove 13 in the gear main body 10.
A regulating body 17 is provided for setting the maximum displacement in the axial direction of the flexible tooth portion 12a from 4 to 4.

This regulating body 17 includes a pair of regulating pieces 17a, 17b disposed on both sides of the flexible tooth portion 12a near the groove 13, and these regulating pieces 17a, 17b.
17b, and a mounting piece 17d attached to the side surface of the gear body 10.
One of the regulating pieces 17b is inserted into the window hole 16, and the mounting piece 17d is attached to the side surface of the gear body 10 using attachment means such as a caulking pin 18. Although the connecting piece 17c is not necessarily required, by providing this connecting piece 17c,
This makes it possible to restrict the radial deflection of the flexible tooth portion 12a.

Further, the connecting piece 17c of the regulating body 17 receives the flexible tooth portion 12a and connects the flexible tooth portion 12a.
It has a function of preventing bending of the gear body 10 toward the center of the gear body 10.

Further, the amount of displacement in the axial direction of the flexible tooth portion 12a is preferably about 1 to 2 m/m, but the tooth portion 12a may also be deflected to the extent that it comes into contact with an adjacent chain gear, or to the extent that it overlaps.

Further, although the groove 13 and the bending portion 14 are provided at one location as shown in FIG. 2, they may be provided at multiple locations. Further, the split groove 13 and the bending portion 14 are connected to the gear body 1 as shown in FIG.
It is preferable that the groove 13 is positioned near the top dead center of the crank K when the crank K is mounted on the crank K.

When replacing the chain C by operating the front derailleur FD, this is done while the chain C is driven and rotated by the crank K having the crank arm CA, as shown in Fig. 1. The foot torque transmitted to the crank arm CA by depressing the pedal is minimum when the crank arm CA is located near top dead center,
This is because the torque acting on the chain C is also minimized, resulting in the least resistance, allowing the chain C to move in the axial direction, thereby further improving the speed change function.

In addition, the chain gear shown in the drawing has the above-mentioned split groove 1.
The tops of the two teeth located on the front side in the drive rotation direction of the gear body 10 from 3 are cut out to lower the height of the teeth and reduce the amount of engagement with the chain. By doing so, when changing the chain from the small diameter chain gear 2 to the large diameter chain gear 1, the chain displaced toward the large diameter chain gear 1 is moved from the notched teeth 11a, 11a portion to the outer side of the tooth portion 12 of the large diameter chain gear 1. Also, when changing the chain from the large-diameter chain gear 1 to the small-diameter chain gear 2, the chain that is displaced toward the small-diameter chain gear 2 is
Since it can be easily displaced from the portions a and 11a to the small diameter chain gear 2 side, the speed change performance can be further improved.

Next, the chain gear 1 configured as described above is installed in the first
The speed change operation when used in the front side multi-stage chain gear device FG as shown in the figure will be explained.

In order to change the chain C from the large diameter chain gear 1 to the small diameter chain gear 2, be sure to operate the front derailleur FD and move the chain C to the small diameter chain as shown in Figure 6. Pressure F ₁ is applied to the chain gear 2 side to make the chain C inclined between the large diameter chain gear 1 and the small diameter chain gear 2.

In this state, when the flexible tooth portion 12a reaches a position near the top dead center of the crank k, the flexible tooth portion 12a is moved toward the gear main body 1 by the pressing force of the chain C by the chain guide CG.
0 to the small diameter chain gear 2 side. At this time, the side edge of the link plate of the chain C meshing with the large-diameter chain gear 1 is pressed against the outer surface of the teeth 11 of the large-diameter chain gear 1, and the chain at this pressed portion has a small diameter. The chain is gouged out to the chain gear 2 side, and the chain in this gouged part is the tooth 11 of the large diameter chain gear 1.
tooth 1 of large diameter chain gear 1.
1, but before this chain C comes off from the teeth 11 of the large diameter chain gear 1, the flexible tooth portion 12a has been displaced toward the small diameter chain gear 2, and the teeth of the large diameter chain gear 1 of the chain C have been displaced. 1
Since the surface pressure at the gouged portion between the chain C and the chain C can be reduced, the chain C can be easily and easily removed from the large diameter chain gear 1. Therefore, the chain C that comes off from the large diameter chain gear 1 can be moved to the small diameter chain gear 2 side without any difficulty.

In addition, in the above configuration, the small diameter chain gear 2
When replacing chain C with large diameter chain gear 1, operate the front derailleur FD as above,
The chain C is pressed _F1 toward the large-diameter chain gear 1 as shown in FIG. 7, and the chain C is inclined between the small-diameter chain gear 2 and the large-diameter chain gear 1. When the portion 12a is located near the top dead center of the crank K, the bending tooth portion 12a is displaced from the bending portion 14 to the opposite side of the small diameter chain gear 2 due to the pressing force of the chain C by the chain guide CG. be.

Therefore, the chain C is connected to the large diameter chain gear 1.
Therefore, the chain C meshes easily and smoothly with the tooth 11b that follows the flexible tooth portion 12a of the gear body 10.

The embodiment described above is applied only to the large diameter chain gear 1 of the front side multi-stage chain gear device FG, but it can also be applied to the small diameter chain gear 2. In this case, changing the chain from the small diameter chain gear 2 to the large diameter chain gear 1 can be improved.

Furthermore, it can be applied to the rear side multi-stage chain gear device RG, and also to the front side multi-stage chain gear device.
It can also be applied when the FG is formed by three or more chain gears.

Effects of the Invention As described above, the present invention provides a gear body having a large number of teeth with a split groove extending from the tooth portion of the gear body toward the center, and a side further from the split groove toward the front in the drive rotation direction of the gear body. A chain gear which is to be replaced is provided with a flexible part of a predetermined length for displacing the tooth part in the axial direction of the gear body, and the tooth part in this flexible part is pressed in the axial direction of the chain by a derailleur. When changing the chain from a small-diameter chain gear to a large-diameter chain gear, the chain displaced toward the large-diameter chain gear can be easily moved to the outside of the teeth of the large-diameter chain gear, which improves speed change. Moreover, when changing the chain from a large-diameter chain gear to a small-diameter chain gear, it is possible to reduce the surface pressure at the scooped part of the chain that is scooped toward the small-diameter chain gear between the teeth of the large-diameter chain gear. This makes it easier to remove the gear from the teeth of the large-diameter chain gear, improving shifting performance.

[Brief explanation of drawings]

Fig. 1 is a front view of the entire bicycle transmission to which the chain gear of the present invention is applied, Fig. 2 is a front view showing an embodiment of the chain gear of the present invention, Fig. 3 is a plan view of only the main parts, and Fig. 4 is Fig. 5 is a front view of only the main parts showing another embodiment, and Figs. 6 and 7 show a chain gear of the present invention with a large diameter, a conventional chain gear with a small diameter, and a large diameter chain gear. It is an explanatory view showing a state when changing a chain from a chain gear to a small diameter chain gear or from a small diameter chain gear to a large diameter chain gear. 10...Gear body, 11...Teeth, 12...Tooth portion, 1
3...Split groove, 14...Flexible part, FG...Front side multi-stage chain gear device.

Claims (1)

[Claims] 1. A bicycle chain gear that constitutes a multi-stage chain gear device, which has a gear body with a large number of teeth,
A split groove extending toward the center from the tooth portion of the gear body is provided, and a predetermined flexure for displacing the tooth portion in the axial direction of the gear body from the groove to the front side in the drive rotation direction of the gear body. A bicycle chain gear characterized by having a section.