JPH02118231A - Link for silent chain - Google Patents

Abstract

PURPOSE:To prevent the generation of noise caused by collision by forming an outside tooth surface into all arc shaped face so as to make the teeth of a link slide into the teeth of a sprocket at the time of engaging the link. CONSTITUTION:At the time of engaging a silent chain to which a number of links 1 are linked with a sprocket, when, e.g., the sprocket 10 is rotated in the arrow direction to engage the links 1 having the holes 2, 3 of the silent chain with the sprocket in order, as a preceding link comes to rest with respect to the sprocket, the following link is revolted centering around O' and, further the next but one link 1 is equally revolved and a link tooth 4 enters between the teeth 11a and 11b of the sprocket. At this time, due to the property of the arc shaped curved face of an inside tooth surface 7, the inside tooth face 7 is slidingly brought into contact with the teeth surface of the sprocket while making the link tooth 4 slide in between the teeth 11a, 11b. Hence, the noise of the chain caused by the collision of the link and sprocket can be prevented.

Description

[Detailed description of the invention] (b) Industrial application field The present invention relates to links for silent chains.

More specifically, the present invention relates to a link for a silent chain in which the link teeth come into sliding contact with the sprocket teeth at the start of meshing with the sprocket or when separating from the sprocket.

(b) Prior art In a winding transmission mechanism having a connection part at each pitch, such as a silent chain or a roller chain, when the chain is wrapped around a sprocket, rotational movement is performed around the connection part. Such a winding transmission mechanism generates a unique noise during operation, and the sources of this noise are: ■ Impact noise between chain parts, ■ String vibration sound of chain spars, ■ Collision between link plate and sprocket. The meshing noises caused by this can be classified into six types.

Among these noises, the sounds generated by ■ and ■ are white noise-like sounds, and when used as components of four-wheeled vehicles or two-wheeled vehicles, it is easy to implement countermeasures against inherent noise and does not pose much of a problem. The meshing noise caused by this is a periodic high-pitched sound that is proportional to the number of sprocket rotations and the number of teeth. This sound is caused by the tooth surface C of the link plate a meeting the tooth surface d of the sprocket b at the end of the rotational movement about the link pin p, which is performed just before the link plate a meshes with the sprocket b, as shown in FIG. This is caused by a collision at point A, and is extremely unpleasant to the ears, making it difficult to take measures for sound insulation.

In order to reduce such noise, there have conventionally been methods to reduce the collision speed by changing the meshing pressure angle between the sprocket and the chain;
As shown in Publication No. 7333 or U.S. Pat. No. 3,495,468, there is a method in which the tooth surface of the sprocket is shaved off in places so that it does not come into contact with the chain, thereby scattering the meshing period, or [F] JP-A-58- No. 196347 or JP-A-57-
As shown in Japanese Patent No. 22443, a method has been adopted in which link plates with different meshing timings are arranged irregularly in one chain to scatter the meshing periods.

However, the above method (■) cannot be expected to be very effective, and the method (2) or (3) reduces the difference between periodic peak sounds and other sounds, reducing the harshness of the ear, but it creates new low-frequency sounds. There are problems that arise.

(c) Problems to be Solved by the Invention The problem to be solved by the present invention is to ensure that when the links of the silent chain are engaged with the sprocket, the teeth of the links slide into the teeth of the sprocket so that the teeth mesh with each other. This prevents the generation of noise due to collision between the link and the sprocket.

B) Means for Solving the Problems In order to solve the above problems, the present invention provides a pair of holes into which the connecting member is inserted, and a pair of holes formed at positions corresponding to the holes and inserted between the teeth of the sprocket. link teeth, and the link teeth are defined by an inner tooth surface and an outer tooth surface that are oblique with respect to a line passing through the center of the pair of holes, the outer tooth surface being The center of curvature is the center of the hole corresponding to the link tooth other than the one link tooth defined by the outer tooth surface, and another link adjacent to the link on the side of the two link teeth is connected to the sprocket. When fixed on the outer periphery of the sprocket, the center of curvature is the center of curvature, and the radius of curvature is the radius of a circle circumscribing the tooth surface of the tooth of the sprocket that engages with the other link tooth. ing.

(e) Effect In the above configuration, when transmitting power by connecting a large number of links with connecting members and wrapping an endless chain around a sprocket, the link has already been fully engaged just before the link engages with the sprocket. The link tooth rotates about the link that is stationary with respect to the sprocket, and the link tooth enters between the teeth of the sprocket, and at this time, the tooth surface of the link tooth slides into contact with the tooth surface of the sprocket.

(f) Example Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, a link 1 for a silent chain is shown. In the figure, 2 and 3 are holes into which link connecting members, for example, connecting pins, are inserted, and 4 and 5 are link teeth provided at positions corresponding to the holes 2 and 3, respectively.

Each link tooth 4 and 5 is defined by an outer flank 6, 8 and an inner flank 7, 9 which are oblique with respect to the line X--X connecting the centers of the holes 2 and 3.

The inner tooth surface 7 is on the extension line of line X-X and the distance between the center of hole 2 and the center of hole 6, that is, the pitch p
It is formed of an arcuate surface having a radius of curvature R and centered at a point 0' separated by a distance. This point O' is the point of another adjacent link (not shown) connected by a connecting member (not shown) inserted into the hole 2 corresponding to the link tooth 4 defined by the inner tooth surface 7. It is also the center of one hole.

The radius of curvature R is such that the further adjacent link connected to the adjacent other link with the center at point 0' has sprocket 1.
When the sprocket is in a stationary state by meshing with the tooth No. 0, the two teeth 11a of the sprocket that are centered on the point O' and into which the link tooth 4 should fit, as shown in FIG.
, Ilb, the tooth surface 12 of the tooth 11b that contacts the inner tooth surface.
It is the radius of curvature of the circular arc circumscribing b.

The other inner tooth surface 9 is the center line of the link Y-Y
The detailed explanation will be omitted since it can be formed in the same manner as described above in an antisymmetrical manner.

The outer tooth surfaces 6 and 8 may be either round or curved surfaces as long as they do not come into contact with the teeth of the sprocket 10 when the link meshes with the sprocket.

When a silent chain in which a large number of links 1 are connected is engaged with a sprocket, for example, sprocket 10
rotates in the direction of the arrow, and the links of the silent chain engage the sprockets one after another. When the preceding link is stationary with respect to the sprocket, the next link is O'
The next link 1 turns in the same manner, and the link tooth 4 enters between the teeth 11a and 11b of the sprocket. At this time, due to the nature of the arcuate curved surface of the inner tooth surface 7, the link tooth 4 slides between the teeth 11a and 11b while the inner tooth surface 7 slides into contact with the surface of the sprocket. Therefore, it is possible to prevent noise caused by conventional chains due to collisions between links and sprockets.

In FIG. 3, a link 1' for a silent chain according to an embodiment of the invention is shown. In the same figure, 2' and 3' are holes, 4' and 5' are link teeth, and 6' and 8' are holes.
is the outer tooth surface, and 7' and 9' are the inner tooth surfaces.

In this embodiment, the outer tooth surface 6' is an arcuate surface with a curvature center O of a hole 2 other than the hole 2 corresponding to the link tooth 4' defined by the outer tooth surface and a curvature R'. The other outer tooth flank 8' is formed by a hole 3 corresponding to a link tooth 5' defined by that outer tooth flank 8'. The center of the hole 2', which is different from the hole 2', is the center of curvature and is formed of an arcuate surface with a curvature R'.

The radius of curvature R' is determined in the same manner as in the previous embodiment. That is, for example, when the link adjacent to the right side of the link 1' meshes with the outer periphery of the sprocket and becomes stationary with respect to the sprocket (K), the center of curvature is the center O of the hole 2', and the two sprockets in which the link teeth 51 are inserted. This is the radius of curvature of an arcuate surface circumscribing the tooth surface of a tooth (not shown) that the tooth surface 8' contacts.

In this embodiment, the inner tooth surfaces 71 and 9' may have a 100-degree angle or a curved surface as long as they do not come into contact with the teeth of the sprocket during meshing operation. Furthermore, it may be formed into an arcuate surface with a curvature R', similar to the silent chain shown in FIG.

In the link 1' of this embodiment, when the link 1' engages with the sprocket, the outer tooth surface comes into sliding contact with the tooth surface of the corresponding sprocket tooth as in the previous embodiment, so that the link and the sprocket tooth do not interact with each other as in the prior art. Noise generation due to collisions can be prevented.

(g) Effect According to the present invention, the following effects can be achieved.

■ When a link meshes with a sprocket, the tooth surface of the link and the tooth surface of the corresponding sprocket come into sliding contact, causing the link tooth to slide between the teeth of the sprocket, eliminating collision between the teeth and causing meshing noise. can be prevented from occurring.

@ In (2) above, when the link teeth slide between the sprocket teeth, part of the tension that acts on the chain is shared, so the pressure between the connecting member and the inner surface of the hole in the link is reduced, and wear on the link connecting portion can be reduced.

θ By randomly using the links of the present invention in the conventional chain (2) described above, it is possible to manufacture a chain that reduces meshing noise and does not generate low-frequency noise.

[Brief explanation of the drawing]

Figure 1 is a plan view of an example of a silent chain link.
Fig. 2 is a diagram showing how to take the curvature of the arc-shaped inner tooth surface of the link in Fig. 1 and the meshing operation of the sprocket of the link, and Fig. 6 is a plan view of a link for a silent chain according to an embodiment of the present invention. , FIG. 4 is a diagram showing a state in which the links of a conventional silent chain collide with the teeth of a sprocket. 1.1': Link 2, 2-3. s-: Hole 4, 4? 5.5. ': Link teeth 7, 7. '9.9. ': Inner tooth surface 6, 6. 's, 8-: Outer tooth surface 10: Sprocket

Claims (1)

[Claims] It has a pair of holes into which the connecting member is inserted, and a pair of link teeth formed at positions corresponding to the holes and inserted between the teeth of the sprocket, and a line through which the link teeth pass through the center of the pair of holes. In a link for a silent chain defined by an inner tooth flank and an outer tooth flank that are oblique with respect to The center of curvature is the center of curvature, and when another adjacent link connected to the link on the side of the one link tooth is fixed on the outer periphery of the sprocket, it engages with the other link tooth with the center as the center of curvature. A link for a silent chain, characterized in that it is formed of an arcuate surface whose radius of curvature is the radius of a circle circumscribing the tooth surface of the tooth of the sprocket.