JPH0247118Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The present invention is a multi-stage sprocket device for bicycles, more specifically, it comprises at least two cross-set sprockets with a difference in the number of teeth of one tooth, and is mainly used for the rear of bicycles. The present invention relates to a multi-stage sprocket device for a bicycle, which is mounted on a wheel hub and is configured to change gears by moving a chain in the axial direction of the sprocket using a derailleur and replacing it with one of the sprockets.

(Prior Art) Generally, in a multi-stage sprocket device on the rear side of a bicycle, the tips of the teeth of each sprocket are arranged at the center between one side and the other side in the thickness direction of the sprocket body. So, the difference in the number of teeth is 1
There are two cases: a cross assembly using at least two sprockets with teeth, and a wide assembly using at least two sprockets with a difference in the number of teeth of two or more teeth. When changing the chain from the small-diameter sprocket with a small number of teeth to the large-diameter sprocket with a large number of teeth using a derailleur, if a wide assembly is used, the chain meshing with the small-diameter sprocket will be on the large-diameter sprocket. It is pressed toward the sprocket side and 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. In this case, the chain meshing with the small-diameter sprocket is pushed toward the large-diameter sprocket and lifted from the small-diameter sprocket teeth, and the lifted portion of the link plate engages the teeth of the small-diameter sprocket. Once it rides on the tip surface, it comes into contact with the tip of the large diameter sprocket tooth and engages with the large diameter sprocket tooth, so the engagement with the large diameter sprocket tooth of the chain is wide. This is worse than a combination, and it becomes difficult to shift.

(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, in addition, the tips of conventional sprocket teeth are located at the center between one side and the other side in the thickness direction of the sprocket body, so when cross-assembled, the tips of the teeth of the sprocket on the small diameter side The lifted chain was difficult to move toward the large diameter sprocket side with respect to the small diameter sprocket teeth, and the chain lifted from the small diameter sprocket teeth had its link plate close to the small diameter sprocket teeth. Since it was difficult to climb onto the tooth tip surface, even if the sprocket tooth was lifted up against the small diameter sprocket tooth, it often slipped off. 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.

The purpose of this invention is to replace the chain from the small-diameter sprocket to the large-diameter sprocket when changing the chain from the small-diameter sprocket to the large-diameter sprocket in cross-assembled gears, which have poor shifting performance compared to wide-diameter sprockets.
The chain lifted from the small-diameter sprocket teeth can be easily moved toward the large-diameter sprocket side relative to the small-diameter sprocket teeth, and the chain lifted from the small-diameter sprocket teeth can be placed on the tip end surface of the small-diameter sprocket teeth. By making it easy to raise the gears, it is possible to improve the speed change performance in the case of cross assembly.

(Means for Solving the Problems) Therefore, the present invention is a multi-stage sprocket device comprising at least two sprockets with a difference in the number of teeth of one tooth. , Large diameter sprocket 2 with many teeth
a first tooth group 1A consisting of a plurality of teeth 11 with chamfered outer surfaces;
A second tooth group 1B consisting of a plurality of teeth 12 with chamfered inner surfaces are provided adjacent to each other in the circumferential direction.

In the present invention, "chamfer" refers to not only the case where the outer or inner surface of the tooth is sloped by cutting or molding so that the wall becomes thinner from the bottom side to the tooth tip, but also the case where the wall thickness is the same. This also includes teeth in which the entire tooth or the tip of the tooth is displaced between the outer surface and the inner surface.

(Function) In cross assembly, when changing the chain from the small diameter sprocket 1 to the large diameter sprocket 2, the chain lifted with respect to the teeth of the small diameter sprocket is moved by the chamfered portion of the teeth 11 in the first tooth group 1A. In addition, the lifted chain tends to cause its link plate to ride on the tooth tip surface of the teeth 12 in the second tooth group 1B, and the cross assembly Therefore, it is possible to improve the speed change performance in various cases.

(Example) The multi-stage sprocket device shown in FIG. 8 has seven sprockets with a difference in the number of teeth of one tooth.
This is a cross-assembly multi-stage sprocket device that combines sprockets with 12 to 18 teeth, and is installed on a rear wheel hub and used with a rear derailleur.

Therefore, in the present invention, of the two adjacent sprockets, the smaller diameter sprocket 1 has fewer teeth.
In addition, a first tooth group 1A includes a plurality of teeth 11 having a chamfered outer surface 11a for the large diameter sprocket 2 with a large number of teeth, and a plurality of teeth 12 having a chamfered inner surface 12a for the large diameter sprocket 2. The second tooth group 1B, which constitutes one set, is provided adjacently in the circumferential direction.

In the above configuration, the first tooth group 1A and the second tooth group 1B have at least two adjacent teeth.
For example, in the case of a sprocket with 13 teeth, three adjacent teeth are set as one set as shown in Figure 1.
It is preferable that two sets of second tooth groups 1B are provided in symmetrical positions as a set, and a first tooth group 1A including three and four adjacent teeth is provided between these second tooth groups 1B.

Moreover, the teeth 11 of the first tooth group 1A and the second tooth group 1
The tooth 12 of B is chamfered 1 so that the tooth thickness at the tip is less than 1/2 of the tooth thickness at the root.
1a and 12a, the tips of these teeth 11 and 12 are preferably displaced toward the outer surface and the inner surface with respect to the center line between one side and the other side in the thickness direction of the sprocket body.

Furthermore, the chamfers 11a and 12a are formed by cutting or molding the side surfaces of the teeth so that they become thinner from the bottom side toward the tip of the tooth.
In addition, for example, the entire tooth or the tooth tip may be displaced between the outer surface side and the inner surface side with the same wall thickness. Further, the tips of the chamfered teeth 11 and 12 are made parallel to the center line between one side and the other side in the thickness direction of the sprocket body, but they may also be made inclined with respect to the center line. It's good.

The illustrated multi-stage sprocket device has 1 tooth.
The first tooth group 1 is attached to the small diameter sprocket 1 having 3 teeth and the large diameter sprocket 2 having 14 teeth.
A, 2A and first tooth groups 1B, 2B are provided, and these second tooth groups 1A, 2A are displaced in the circumferential direction so as not to overlap in the axial direction, while the second tooth group in the large diameter side sprocket 2 The tooth 22 of 2B is
The height of the teeth 22 is higher than that of the teeth 21 of the tooth group 2A.
b. This high tooth 22b is the first tooth group 2A.
For example, if the height of the tooth 21 is 4.7 mm, the height of the tooth 21 is 6 mm.
It has a height of .

Further, the teeth 12 of the second tooth group 1B on the small diameter sprocket 1 are made higher than the teeth 11 of the first tooth group 1A, similar to the teeth 22 of the second tooth group 2B on the large diameter sprocket 2. It has high teeth 12b.

Therefore, when changing the chain from the small diameter sprocket 1 to the large diameter sprocket 2 in the cross-assembled multi-stage sprocket device as described above,
The third sprocket tooth on the small diameter side is installed by the derailleur.
As shown in the figure, when the meshing chain is pressed toward the large-diameter sprocket 2 and lifted against the teeth 11 of the first tooth group 1A on the small-diameter sprocket 1, the The outer surfaces of the teeth 11 of the first tooth group 1A are chamfered 11a as shown in FIG. 2, and the tips of the teeth are displaced toward the large diameter sprocket 2, so that the lifted chain can be moved as shown in FIG. The chamfered portion 11a of the tooth 11 makes it easier to move the tooth 11 toward the larger diameter sprocket 2 side. The chain, which is lifted relative to the teeth 11 of the first tooth group 1A and moved toward the large diameter sprocket 2 with respect to the teeth 11, is moved toward the second tooth group 1B in the small diameter sprocket 1 as shown in FIG. At this time, the second tooth group 1 rides on the tooth tip surface of the tooth 12.
The tooth 12 of B has a chamfered inner surface 1 as shown in Fig. 2.
2a, and the tooth tip side is displaced to the side opposite to the large diameter side sprocket 2, so the teeth 11 of the first tooth group 1A
On the other hand, it is easier to place the chain, which is closer to the larger diameter sprocket 2, on the tooth tip surfaces of the teeth 12 of the second tooth group 1B.

Therefore, the chain meshing with the sprocket teeth on the small diameter side can be easily brought close to the teeth 11 of the first tooth group 1A and placed on the teeth 12 of the second tooth group 1B. The sprocket 1 can be quickly replaced with the larger diameter sprocket 2, and the speed change performance can be improved.

Further, by providing second tooth groups 1B and 2B on the small diameter sprocket 1 and large diameter sprocket 2, and displacing these second tooth groups 1B and 2B in the circumferential direction, the second tooth group on the small diameter sprocket 1 Since the chain riding on the teeth 12 of the tooth group 1B can be easily caught by the teeth 22 of the second tooth group 2B on the large-diameter sprocket 2, shifting performance can be further improved.

Also, the second tooth group 2 on the large diameter side sprocket 2
By making the teeth 22 of B have high teeth 22b, the chain that has climbed on the teeth 12 of the second tooth group 1B in the small diameter side sprocket 1 can be moved to the teeth 2 of the second tooth group 2B.
2 makes it even easier to catch the gear, so shifting performance can be further improved.

Further, the teeth 12 of the second tooth group 1B on the small diameter sprocket 1 are made high teeth 12b, and the teeth 21 of the first tooth group on the large diameter sprocket 2 are made the teeth of the second tooth group 1B, as shown in FIG. 12 in the axial direction, the gap between the small diameter sprocket 1 and the large diameter sprocket 2 is narrow relative to the width of the chain, and the chain that would normally be lifted relative to the small diameter sprocket teeth is Even when the chain does not ride on the teeth of the small diameter sprocket, the chain lifted up against the teeth 11 of the first tooth group 1A in the small diameter sprocket 1 is moved over the teeth 12 of the second tooth group 1B.
This allows the vehicle to ride on the vehicle and improves shifting performance.

In addition, the multi-stage sprocket device of the present invention is configured by combining only sprockets with a difference in the number of teeth of 1 tooth, as well as at least two sprockets with a difference in the number of teeth of 1 tooth, and a sprocket with a difference in the number of teeth of 2 teeth or more. It may also be configured by combining at least one sprocket with a sprocket.

In addition, in the above embodiment, the small diameter side sprocket 1
and the large diameter side sprocket 2.
Although the tooth groups A, 2A and the second tooth groups 1B, 2B are provided, they may be provided only on the small diameter sprocket 1. However, when three or more sprockets with a difference in the number of teeth of one tooth are combined, it is preferable to provide the first tooth group and the second tooth group on each small diameter sprocket except for the largest diameter sprocket.

Further, when the teeth of the first tooth groups 1A and 2A are made of high teeth, it is preferable that all the teeth are made of high teeth, but only one tooth may be made of high teeth.

(Effects of the invention) As described above, the present invention combines a small-diameter sprocket 1 with a small number of teeth with a large diameter sprocket with a large number of teeth in a multi-stage sprocket device which is made up of cross-assembled at least two sprockets with a difference in the number of teeth of one tooth. A first tooth group 1A including a plurality of teeth 11 with a chamfered outer surface relative to the diameter side sprocket 2, and a second tooth group 1B including a plurality of teeth 12 with a chamfered inner surface relative to the large diameter side sprocket 2 as one set. are provided adjacent to each other in the circumferential direction, so that when changing the chain from the small diameter sprocket 1 to the large diameter sprocket 2, the chain lifted from the small diameter sprocket teeth is moved to the first tooth group 1.
Due to the chamfered portion of the tooth 11 at A, the tooth 1
In addition, the chain lifted from the small diameter sprocket teeth can be moved closer to the second tooth group 1B.
Since it is possible to easily ride on the tooth tip surface of the teeth 12 in the cross-assembled case, the speed change performance can be improved.

[Brief explanation of the drawing]

Fig. 1 is a partially omitted front view showing one embodiment of the device of the present invention, Fig. 2 is a sectional view of only the main parts, and Fig. 3 is a partially omitted front view showing an embodiment of the device of the present invention.
7 to 7 are explanatory diagrams showing a state in which the chain is replaced, and FIG. 8 is a partially cutaway side view of the whole. 1... Small diameter side sprocket, 2... Large diameter side sprocket, 11... Teeth of the first tooth group, 12... Second
Teeth of the tooth group.

Claims (1)

[Scope of utility model registration request] A multi-stage sprocket device comprising at least two sprockets with a difference in the number of teeth of one tooth, in which a small-diameter sprocket 1 with a small number of teeth has a plurality of chamfered outer surfaces relative to a large-diameter sprocket 2 with a large number of teeth. First tooth group 1A including teeth 11 as one set
and a second tooth group 1B including a plurality of teeth 12 with chamfered inner surfaces relative to the large diameter side sprocket 2.
A multi-stage sprocket device for a bicycle, characterized in that: and are provided adjacent to each other in the circumferential direction.