JPH0247119Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The invention is a multi-stage sprocket for bicycles, more specifically, a large number of teeth are provided around the outer periphery of the sprocket body, and a chain is engaged with these teeth to adjust the pedal force. The present invention relates to a bicycle sprocket that transmits power to the rear wheel, and is mainly used in a multi-stage sprocket device attached to the rear wheel hub of the bicycle.

(Prior art) In general, this type of sprocket is constructed by combining multiple sprockets with different numbers of teeth to form a multi-stage sprocket device. There are two types of sprockets: one is a combination, and the other is a wide assembly using at least two sprockets with a difference in the number of teeth of two or more. When changing the chain from a small-diameter sprocket with a small number of teeth to a large-diameter sprocket using a derailleur, when a wide assembly is used, the chain meshing with the small-diameter sprocket is pushed toward the large-diameter sprocket. It comes into contact with the tip of the large-diameter sprocket tooth, and immediately separates from the small-diameter sprocket tooth and meshes with the large-diameter sprocket tooth, but when cross-assembled, the small-diameter sprocket The chain meshing with the chain is pressed toward the large diameter sprocket and lifted from the small diameter sprocket teeth, and the lifted portion of the link plate once rides on the tooth tip surface of the small diameter sprocket teeth. Because it comes into contact with the tip of the large-diameter sprocket tooth and engages with the large-diameter sprocket tooth, the mesh with the large-diameter sprocket tooth of the chain is worse than in a wide assembly, making it difficult to shift gears. It becomes difficult.

(Problem to be solved by the invention) When configured with a cross assembly as described above, the meshing of the chain with the teeth of the large diameter sprocket when changing from the small diameter side sprocket to the large diameter side sprocket is worse than in a wide assembly. However, all the teeth of conventional sprockets have the same height, and the tips of the teeth are located in the center between one side and the other side in the thickness direction of the sprocket body. Because of the arrangement, when cross-assembled,
The chain lifted from the small-diameter sprocket teeth was difficult to move toward the large-diameter sprocket with respect to the small-diameter sprocket teeth, and the chain lifted from the small-diameter sprocket teeth was
Since the link plate had difficulty climbing onto the tip surface of the small-diameter sprocket teeth, it often slipped off even if it was lifted up against the small-diameter sprocket teeth. For this reason, when cross-assembled, the meshing with the large-diameter sprocket teeth of the chain became even worse, resulting in poor shifting performance.

Also, the height of the conventional sprocket teeth is
As mentioned above, they are all at the same height, and
Since the tips of the teeth are disposed at the center between one side and the other side in the thickness direction of the sprocket body,
When changing the chain from the small-diameter sprocket to the large-diameter sprocket, unless the chain is bent a certain amount in the direction of the large-diameter sprocket, it cannot come into contact with the tips of the teeth of the large-diameter sprocket.
As a result, it was difficult for the large-diameter sprocket teeth to catch the chain moving from the small-diameter sprocket to the large-diameter sprocket, and the shifting performance was that much worse.

The main purpose of this invention is to
When changing the chain from the small-diameter sprocket to the large-diameter sprocket, the chain lifted from the small-diameter sprocket teeth can be easily brought to the large-diameter sprocket side relative to the small-diameter sprocket teeth, and the chain can be lifted from the small-diameter sprocket teeth. By making it easier for the attached chain to ride on the tooth tip surface of the small-diameter sprocket teeth, it is possible to improve shifting performance in the case of cross assembly.
Another purpose is to quickly catch the chain moving from the small-diameter sprocket to the large-diameter sprocket when changing the chain from the small-diameter sprocket to the large-diameter sprocket. .

(Means for Solving the Problems) Accordingly, the present invention provides a sprocket in which a large number of teeth 2 are provided around the outer periphery of a sprocket body 1, and the sprocket body A first tooth group 2A consisting of a plurality of teeth 21 having one side facing one side in the thickness direction chamfered as one set.
and a second tooth group 2B including a plurality of teeth 22 whose other side face facing the other side in the thickness direction is chamfered,
At least one tooth in this second tooth group 2B is made higher than the other teeth to form a high tooth 22b.

In this invention, "chamfer" refers to not only one side or the other side of the tooth 2 that is sloped by cutting or molding so that the wall becomes thinner from the bottom side to the tooth tip, but also the same. Thick and whole tooth, or
This also includes those in which the tooth tips are displaced from the one side to the other side.

(Function) When used as the small-diameter sprocket of a cross-assembled sprocket in a multi-stage sprocket device, when changing the chain from the small-diameter sprocket to the large-diameter sprocket, the chain lifted against the small-diameter sprocket teeth is The chamfered portion of the teeth 21 in the tooth group 2A makes it easy to move the link plate toward the larger diameter sprocket B, and the lifted chain moves its link plate to the tip of the tooth 22 in the second tooth group 2B. It is easy to ride on the surface, and it is possible to improve shifting performance when cross-assembled.

In addition, when used as a large diameter sprocket in a multi-stage sprocket device, when changing the chain from the small diameter sprocket to the large diameter sprocket, the chain moving to the large diameter sprocket side is Since the high teeth 22b allow the gear to be caught quickly, shifting performance can be improved.

(Example) In the figure, 1 is an annular sprocket body having a center hole, and a large number of teeth 2 are provided around the outer periphery at predetermined intervals.

Therefore, the present invention provides the sprocket body 1
On the outer periphery of the sprocket body 1, there is a first tooth group 2A consisting of a plurality of teeth 21 with a chamfer 21a on one side facing one side in the thickness direction, and a chamfer 22a on the other side facing the other side in the thickness direction. A second tooth group 2B having a plurality of teeth 22 as one set is provided, and this second tooth group 2B
At least one tooth in is made higher than the other teeth to form a high tooth 22b.

In the above configuration, the first tooth group 2A and the second tooth group 2B have at least two adjacent teeth.
Only one set of each set or multiple sets of each set are provided. For example, in the case of a sprocket with 13 teeth, three adjacent teeth are considered as one set as shown in Fig. 1, and two sets of second tooth groups are provided. 2B at symmetrical positions, and between these second tooth groups 2B, it is preferable to provide a first tooth group 2A including three and four adjacent teeth.

In addition, the teeth 21 of the first tooth group 2A and the second tooth group 2B
Teeth similar to those in a general sprocket may be provided between the teeth 22 of the sprocket.

Moreover, the teeth 21 of the first tooth group 2A and the second tooth group 2
The tooth 22 of B is chamfered 2 so that the tooth thickness at the tooth tip is less than 1/2 of the tooth thickness at the root.
1a, 22a, the tips of these teeth 21, 22 are preferably displaced toward one side and the other side with respect to the center line between one side and the other side in the thickness direction of the sprocket body 1. .

The chamfers 21a and 22a are formed by cutting or molding the side surfaces of the teeth 2 so that the walls become thinner from the bottom side toward the tips of the teeth, but otherwise, for example, by pressing the same wall thickness. in,
The entire tooth 2 or the tooth tip may be displaced from the one side to the other side. Further, the tips of the chamfered teeth 21 and 22 are parallel to the center line between one side and the other side in the thickness direction of the sprocket body 1, but they are also made to be inclined with respect to the center line. It is also good.

Moreover, it is preferable that all the teeth 22 of the second tooth group 2B are high teeth 22b. Also, this high tooth 2
The height of the tooth 2b is 6 mm when the height of the teeth 21 of the first tooth group 2A is, for example, 4.7 mm.

Therefore, the sprocket constructed as described above is mainly used as the small-diameter sprocket A of at least two small-diameter and large-diameter sprockets A and B that are arranged in the middle and cross-assembled in a multi-stage sprocket device. And,
When replacing the chain from the small diameter sprocket A to the large diameter sprocket B, which has a tooth difference of 1 tooth, the chain meshed with the teeth of the small diameter sprocket A by the derailleur as shown in Figure 3 will be transferred to the large diameter sprocket B. When the chain is pressed against the teeth 21 of the first tooth group 2A on the small-diameter side sprocket A, the teeth 21 of the first tooth group 2A at the portion facing the lifted portion of the chain have their outer surfaces As shown in Fig. 2, the chamfered portion 21a of the tooth 21 is disposed and the tooth tip side is displaced toward the larger diameter sprocket B, so the lifted chain is attached to the tooth 21 by the chamfered portion 21a of the tooth 21 as shown in Fig. 4. On the other hand, it is easier to move it toward the larger diameter sprocket B side. The chain, which is lifted relative to the teeth 21 of the first tooth group 2A and moved toward the large diameter sprocket B with respect to the teeth 21, is moved toward the second tooth group 2B on the small diameter sprocket A as shown in FIG. At this time, the second tooth group 2 rides on the tooth tip surface of the tooth 22.
The tooth 22 of B has a chamfered inner surface 2 as shown in FIG.
2a, and the tooth tip side is displaced to the side opposite to the large diameter side sprocket B, so the tooth 21 of the first tooth group 2A
On the other hand, it is easier to place the chain that is closer to the larger diameter sprocket B side on the tooth tip surface of the teeth 22 of the second tooth group 2B.

Therefore, the chain meshing with the sprocket teeth on the small diameter side can be easily brought close to the teeth 21 of the first tooth group 2A and placed on the teeth 22 of the second tooth group 2B. The sprocket A can be quickly replaced with the larger diameter sprocket B, and the speed change performance can be improved.

Furthermore, when the sprocket of the present invention is used as the large diameter sprocket B described above and the small diameter sprocket A described above is, for example, a general sprocket, the chain can be changed from the small diameter sprocket A to the large diameter sprocket B. In this case, the teeth 2 of the second tooth group 2B on this large diameter side sprocket B
2 has high teeth 22b, the chain moving to the large diameter sprocket B side is not bent by a predetermined amount in the direction of the large diameter sprocket B, that is, the high teeth 2
Since the tip of the high tooth 22b can be brought into contact with the tip of the high tooth 22b when the amount of deflection is smaller than the amount of deflection when contacting other teeth other than 2b, the high tooth 2
2b allows the chain to be caught more quickly, and the shifting performance can be improved accordingly.

The sprocket of the present invention is preferably used as an intermediate sprocket in a multi-stage sprocket device, but it may also be used as the smallest or largest sprocket.

(Effects of the Invention) As described above, the present invention provides a first tooth group 2A that includes a plurality of teeth 21 on the outer periphery of the sprocket body 1, one set of which is chamfered on one side facing one side in the thickness direction of the sprocket body 1. and a second tooth group 2B including a plurality of teeth 22 whose other side face facing the other side in the thickness direction is chamfered.
Since at least one tooth in the second tooth group 2B is made higher than the other teeth to form the high tooth 22b, by using it as the small diameter side sprocket of the cross-assembled sprocket, the small diameter When changing the chain from the side sprocket to the large diameter sprocket, the chain lifted from the small diameter sprocket teeth is moved to the large diameter sprocket side with respect to the teeth 21 by the chamfered portion of the teeth 21 in the first tooth group 2A. Furthermore, the chain lifted from the small-diameter sprocket teeth can easily ride on the tooth tip surfaces of the teeth 22 in the second tooth group 2B, which improves the shifting performance in the case of cross assembly. It can be done.

For example, by using it as the large-diameter sprocket of a cross-assembled sprocket, when changing the chain from the small-diameter sprocket to the large-diameter sprocket, the chain transfers to the large-diameter sprocket. When the sprocket does not deflect by a predetermined amount in the direction of the radial sprocket, the high teeth 2 of the second tooth group 2B
2b allows the gear to be caught more quickly, resulting in better shifting performance.

[Brief explanation of the drawing]

Fig. 1 is a front view showing one embodiment of the sprocket of the present invention, Fig. 2 is a sectional view, Figs. FIG. 1...Sprocket body, 2...Teeth, 2A...
1st tooth group, 21...teeth of the 1st tooth group, 2B...2nd
Teeth group, 22...Teeth of second tooth group, 22b...Tall teeth.

Claims (1)

[Scope of utility model registration request] This is a sprocket comprising a large number of teeth 2 arranged around the outer periphery of a sprocket body 1, the plurality of teeth 21 having chamfered one side facing one side in the thickness direction of the sprocket body 1.
A first tooth group 2A having a set of A bicycle sprocket characterized in that at least one tooth is higher than the other teeth to form a high tooth 22b.