JPH034636Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a sprocket assembly mainly used for bicycles, and more particularly, to a sprocket assembly consisting of a cylindrical member and a plurality of sprockets of different diameters coupled to the outer periphery of the cylindrical member. .

Usually, in this type of assembly, the sprocket is coupled to the cylindrical member by providing a plurality of engagement grooves extending in the axial direction on the outer periphery of the cylindrical member, and on one side of the engagement groove in the axial direction. A screw is provided, and a plurality of protrusions that fit into the engagement grooves are provided on the inner periphery of the center hole of the other large diameter sprockets other than the smallest diameter sprocket located on the outermost side, and these large diameter sprockets are
The sprockets are fitted sequentially at regular intervals starting from the largest diameter sprocket via spacers, and an internal thread is provided on the inner periphery of the center hole of the smallest diameter sprocket, and the smallest diameter sprocket is screwed onto the thread of the cylindrical member. It is connected by

However, since the minimum diameter sprocket is screwed in the direction that tightens during normal rotation to prevent it from loosening inadvertently, the driving torque is transferred from the chain hanging on the minimum diameter sprocket to the minimum diameter sprocket. When the transmission is transmitted, this minimum diameter sprocket rotates in the spiral direction and tightens, making it extremely difficult to remove.

The present invention was devised in view of the above points, and the purpose is to utilize the second sprocket adjacent to the first sprocket located at the outermost side, and to bias this second sprocket in a direction toward the first sprocket. With a simple structure that only requires interlocking teeth between the elastic body and the facing surfaces of the first and second sprockets, the outermost sprocket can be easily and easily removed without using any special tools. It is something to do.

Therefore, the configuration of the present invention includes a cylindrical member having an engagement groove extending in the axial direction on the outer circumference and a thread on the outer circumference on one side in the axial direction of the engagement groove, and a plurality of sprockets having different diameters. A sprocket adjacent to the first sprocket located at the outermost side is fitted into the engagement groove portion so as to be non-rotatable and movable in the axial direction, and the first sprocket is screwed onto the threaded portion. A sprocket assembly comprising: a second sprocket adjacent to the first sprocket that is biased toward the first sprocket by an elastic body, and a space between opposing surfaces of the first and second sprockets; Engaging teeth are provided to lock the rotation of the first sprocket in the spiraling direction, and when the first sprocket is screwed, the second sprocket is moved against the elastic body to screw the first sprocket into a fixed position. The elastic force of the elastic body moves the second sprocket in a direction close to the first sprocket to engage the meshing teeth, thereby locking the first sprocket from rotating in the spiral direction.

Embodiments of the assembly of the present invention will be described below with reference to the drawings.

In the figure, 1 is a cylindrical member constituting a driving member in a multi-stage freewheel, 21, 2
2, 23, 24, 25, and 26 are sprockets that are coupled to the outer periphery of the cylindrical member 1, and the outer periphery of the cylindrical member 1 has a large diameter portion 13 and a large diameter portion 13 via two stepped portions 11 and 12. A medium diameter portion 14 and a small diameter portion 15 are provided, and a plurality of engagement grooves 16 and 17 extending in the axial direction are provided at predetermined intervals in the circumferential direction on the outer periphery of the large diameter portion 13 and the medium diameter portion 14. In addition, a screw 18 is provided on the outer periphery of the small diameter portion 15, and a ratchet 19 that engages with the pawl of the driven member of the freewheel is provided on the inner periphery, and ball races 20 are provided on both sides of the ratchet 19 in the axial direction. , 20 are provided.

Further, the sprockets 21 to 26 have different outer diameters and have a large number of teeth with different numbers of teeth on the outer periphery. The inner periphery of the sprocket 26 is provided with protrusions that fit into the engagement grooves 16 and 17 in a manner that is non-rotatable and movable in the axial direction. An internal thread 21a is provided to be screwed into the thread 18 portion. Further, these sprockets are held at constant intervals via a spacing member such as an annular spacer 3.

In the sprocket assembly according to this invention, a second sprocket 22 adjacent to the first sprocket 21 is connected to the first sprocket 21 by an elastic body 4.
The first sprocket 21 and the second sprocket 22 are biased toward each other in the approaching direction, and the first
Engaging teeth 5 and 6 are provided to lock the rotation of the sprocket 21 in the spiral direction.

However, in the embodiment shown in the drawings, the elastic body 4
is formed by winding a spring wire into an annular shape and bending the wound portion at several points in the axial direction to be elastically deformable in the axial direction, and this elastic body 4 is connected to the second sprocket 22 and the second sprocket 22 and the third sprocket 23 on the larger diameter side, the second sprocket 22 is biased toward the first sprocket 21, and the boss of the first sprocket 21 is On the inner surface of the part, the second
A spacing cylinder 21b that maintains a constant distance between the sprocket 22 and the sprocket 22 is integrally provided, and meshing teeth 5, 6 made of ratchets are formed on the tip surface of the spacing cylinder 21b and the outer surface of the boss portion of the second sprocket 22. are provided around the sprocket, and the meshing of these meshing teeth 5 and 6 locks the rotation of the first sprocket 21 in the spiraling direction and the rotation in the spiraling direction.

Note that the elastic body 4 may be made of an elastic material such as a coil spring, a plate spring, or rubber.

Further, the meshing teeth 5 and 6 are connected to the first sprocket 2.
The structure is not particularly limited as long as it can prevent the sprocket 1 from rotating in the spiral direction with respect to the second sprocket 22.

Further, the second and third sprockets 22, 23
In between and around the outer circumference of the elastic body 4, an annular elastic cap may be provided to protect the elastic body 4 to prevent the elastic body 4 from rusting.

Further, reference numeral 1a in the figure is an annular collar provided at the end edge of the large diameter portion 13 of the cylindrical member 1.

The present invention is constructed as described above, and among the sprockets 21 to 26, the other large diameter sprocket 23 except the first and second sprockets 21 and 22
- 26 are fitted into the engagement grooves 16 and 17 on the outer periphery of the cylindrical member 1 so as to be movable in the axial direction from the largest diameter sprocket through the spacer 3 at regular intervals, and at the same time, the outer circumference of the engagement groove 17 is The second sprocket 22 is fitted into the engagement groove 17 so as to be movable in the axial direction to prevent rotation of the large diameter sprockets 22 to 26. The sprocket 21 is screwed onto the thread 18 on the outer periphery of the cylindrical member 1 and is advanced to the front position where the meshing teeth 5 and 6 mesh, and the second sprocket 22 is moved against the elastic body 4 to the first position. The first sprocket 21 is moved in the direction away from the sprocket 21, and the first sprocket 21 is screwed to the home position, and the second sprocket 22 is moved in the direction toward the first sprocket 21 by the elastic force of the elastic body 4. The meshing teeth 6 of the second sprocket 22 are connected to the first sprocket 21.
This meshing locks the rotation of the first sprocket 21 in the spiral direction. Thus, when driving torque is transmitted from the chain hanging on the first sprocket 21 to the first sprocket 21, this driving torque is transmitted from the first sprocket 21 to the meshing teeth 5,
6 and the cylindrical member 1 via the second sprocket 22.
The first sprocket 2
1 does not rotate in the spiral direction.

Therefore, the first sprocket 21 is not tightened as strongly as in the conventional case.
The sprocket 22 is moved in a direction away from the first sprocket 21 against the elastic body 4, and the meshing teeth 5, 6 are moved.
By disengaging the first sprocket 21, the first sprocket 21 can be rotated in the loosening direction with a small force and can be easily removed.

Further, since the meshing of the meshing teeth 5 and 6 also locks the rotation of the first sprocket 21 in the screwing direction, the first sprocket 21 does not loosen inadvertently.

Incidentally, the sprocket assembly according to the present invention may have two or more sprockets. If there are two sprockets, for example, the second sprocket 22
An elastic body 4 is interposed between the annular collar 1a of the cylindrical member 1 and the annular collar 1a of the cylindrical member 1.

As described above, the present invention utilizes a second sprocket that is non-rotatably fitted to the cylindrical member and movable in the axial direction, and that is adjacent to the first sprocket located at the outermost side, and that the second sprocket is made of elastic material. Since the first sprocket is biased in the proximal direction by the body and meshing teeth are provided between the opposing surfaces of the first and second sprockets to lock the rotation of the first sprocket in the spiral direction, When the first sprocket is screwed onto the cylindrical member, the second sprocket is moved against the elastic body to screw the first sprocket into a fixed position, and the second sprocket is screwed by the elastic force of the elastic body. The rotation of the first sprocket can be locked by a simple operation of moving the first sprocket toward the first sprocket and engaging the meshing teeth, and yet the second sprocket can be moved away from the first sprocket against the elastic body. by moving the meshing teeth in the direction to disengage the meshing teeth,
The first sprocket can be loosened with a small force, and therefore, the first sprocket can be easily and easily removed without using any special tools.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway front view showing an embodiment of the sprocket assembly of the present invention, Fig. 2 is an enlarged sectional view of the main parts, and Fig. 3 is a partially cutaway front view of the first and second sprockets. FIG. 4 is a side view of only the elastic body, and FIG. 5 is a front view of the same. 1... Cylindrical member, 16, 17... Engagement groove, 18
...Screw, 21...1st sprocket, 22...
Second sprocket, 4... elastic body, 5, 6... meshing teeth.

Claims (1)

[Scope of utility model registration request] It consists of a cylindrical member that has an engagement groove extending in the axial direction on its outer periphery and a thread on the outer periphery of one axial side of the engagement groove, and a plurality of sprockets with different diameters. A sprocket assembly in which a sprocket adjacent to the first sprocket is fitted into the engagement groove portion so as to be non-rotatable and movable in the axial direction, and the first sprocket is screwed onto the threaded portion, the sprocket assembly comprising: The second sprocket adjacent to the first sprocket is connected by an elastic body.
The first sprocket is characterized in that meshing teeth are provided between opposing surfaces of the first and second sprockets to bias the first sprocket in the proximal direction and to lock the rotation of the first sprocket in the spiral direction. sprocket assembly.