JP5637511B2 - Roller chain and chain drive using it - Google Patents

Description

  The present invention relates to a roller chain that can reduce running noise during operation, and a chain driving device that uses the roller chain.

  The roller chain can bend the inner link that connects the left and right inner plates via the front and rear bushings that rotatably mount the roller, and the outer link that connects the left and right outer plates via the front and rear pins. Concatenated. However, one pin of each outer link is rotatably inserted into one bush of each inner link (JIS B 1801).

  On the other hand, in order to reduce the running noise of such a roller chain, the outer diameter of each roller is gradually reduced from the center toward the left and right ends to form a barrel-shaped outer shape, and the sprocket teeth to be combined with the roller chain It has been proposed that the surface be curved concavely in the tooth width direction according to the roller (Patent Document 1). When the roller of the roller chain meshes with the sprocket teeth, the impact force at the start of meshing produces an oblique component along the contact surface between the tooth surface and the roller, so the impact force during meshing is mitigated, Running noise due to impact sound can be reduced.

JP 2007-309488 A

  When such a conventional technique is used, a sprocket for a roller chain having a barrel-shaped roller cannot avoid the problem that tooth surface creation is not easy and productivity is not good. This is because the tooth surface of the sprocket needs to be formed to be concavely curved in the tooth width direction in order to fit the barrel-shaped roller.

  Therefore, in view of the problems of the prior art, an object of the present invention is to provide a symmetrical outer peripheral shape comprising a concave portion at the center in the axial direction of the roller of the roller chain and convex portions that are smoothly continuous on both outer sides of the concave portion. Accordingly, it is an object of the present invention to provide a roller chain that can reduce traveling noise and easily solve the problem of sprocket productivity, and a chain driving device that uses the roller chain.

  The configuration of the first invention according to this application for achieving the above object (referring to the invention according to claim 1, the same applies hereinafter) is smoothly continuous to the concave portion of the central portion in the axial direction and both outer sides of the concave portion It comprises a roller having a symmetrical outer peripheral shape consisting of a convex part, the concave part uniformly increases the outer diameter from the central part toward both outer sides, and each convex part increases the outer diameter toward the outer side. Uniformly increase to form a smooth maximum outer diameter portion, and reduce the outer diameter uniformly from the maximum outer diameter portion to the outside. A gap that smoothly decreases from the center in the center direction toward both outer sides is formed between the outer periphery of the recess and the root, and the roller is elastically deformed in a direction that crushes the gap when it collides with the root. The gist.

  Moreover, the cross-sectional shape of the concave portion is an arc having a concave radius of curvature, and the cross-sectional shape of each convex portion is an arc having a convex radius of curvature from the outside of the concave portion to the maximum outer diameter portion and the outside of the maximum outer diameter portion. It is good.

  The configuration of the second invention (referring to the invention according to claim 3, hereinafter the same) comprises the roller chain according to the first invention and a sprocket around which the roller chain is wound, and the sprocket has a cross-sectional shape of the tooth bottom. The distance from the shaft center is uniformly reduced from the central part in the tooth width direction toward both outer sides to form a symmetrical mountain shape, and each convex part is in contact with the tooth bottom inside the maximum outer diameter part. The gist.

  Further, the convex portion may come into contact with the tooth bottom at the left-right symmetrical linear portion of the tooth bottom cross-sectional shape.

  According to such a configuration of the first invention, the rollers of the roller chain are formed in a bilaterally symmetric outer peripheral shape including a concave portion at the center in the axial direction and convex portions that are smoothly continuous on both outer sides of the concave portion. Therefore, the cross-sectional shape of the root of the sprocket may be formed, for example, in a symmetrical mountain shape or a straight line parallel to the sprocket axis so that the convex part comes into contact with the tooth bottom symmetrically. There is no room for sexual problems. However, in the present invention, “uniformly increase” and “uniformly decrease” mean that the inflection point is not generated, and the increase or decrease is smoothly performed.

  When the roller meshes with the tooth bottom of the sprocket, the convex portion of the roller comes into contact with the tooth bottom of the sprocket symmetrically to form a gap between the outer periphery of the concave portion of the roller and the tooth bottom. Therefore, when the roller collides with the tooth bottom during meshing with the sprocket, it elastically deforms so as to crush this gap, and a part of the generated impact energy is absorbed as roller distortion energy or friction energy with the sprocket. In addition, traveling noise due to impact sound can be reduced.

  If the cross-sectional shape of the concave portion and the cross-sectional shape of each convex portion are arcs, the machining of the roller can be facilitated.

  According to the configuration of the second aspect of the invention, the cross-sectional shape of the sprocket tooth bottom is formed in a mountain shape, and each roller convex portion is brought into contact with the tooth bottom inside the maximum outer diameter portion so that the roller When it collides with the bottom, it becomes easier to elastically deform toward both outer sides in the axial direction, and it is possible to effectively reduce running noise and to prevent the deviation of the roller in the axial direction. This is because the tooth bottom of the sprocket is inclined low and symmetrically toward the outside at the contact position with each convex portion of the roller.

  The sprocket can make machining easier by making the cross-sectional shape of the tooth bottom in contact with the convex part of the roller a symmetrical straight part.

Roller chain configuration diagram Sprocket configuration diagram Main part enlarged operation diagram Test result measurement diagram Configuration explanatory diagram of Comparative Example 1

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  The roller chain 10 connects the left and right inner plates 13, 13 via the front and rear bushes 12, 12 to form the inner link 10 a, and connects the left and right outer plates 15, 15 via the front and rear pins 14, 14. Thus, the outer link 10b is formed, and the inner link 10a and the outer link 10b are alternately connected to be freely bent (FIG. 1A). In addition, one pin 14 of the outer link 10b is rotatably inserted in one bush 12 of the inner link 10a, and a roller 11 is rotatably mounted on each bush 12. However, FIG. 1A is a schematic cross-sectional view at a connecting portion of the roller chain 10, and FIG. 1B is an enlarged vertical cross-sectional view of the roller 11. In FIG. 1A, only one front and rear roller 11, 11, bush 12, 12, and pin 14, 14 are shown.

  The roller 11 of the roller chain 10 has a symmetrical outer peripheral shape comprising a concave portion a1 at the center in the direction of the axis C1 and convex portions b1 and b1 smoothly extending on both outer sides of the concave portion a1 (FIG. 1). (B)). A shaft hole 11a for the bush 12 is formed on the shaft center C1 of the roller 11, and chamfers 11b and 11b are formed at both ends of the shaft hole 11a. However, the outside here refers to the left-right direction with respect to the center in the direction of the axis C1.

  The cross-sectional shape of the concave portion a1 of the roller 11 is an arc having a concave curvature radius R1. The cross-sectional shape of each convex portion b1 is an arc having a convex radius of curvature R2 from the outside of the concave portion a1 to the maximum outer diameter portion e, and an arc having a convex radius of curvature R3 outside the maximum outer diameter portion e. Further, the central positions of the convex radii of curvature R2 and R3 of each convex part b1 are the same as the position of the maximum outer diameter part e in the direction of the axis C1. Each of the end surfaces 11c and 11c of the roller 11 is formed with a ring-shaped plane perpendicular to the axis C1 on the outer periphery of the chamfer 11b.

  The roller chain 10 constitutes a chain drive device in combination with a sprocket 20 around which the roller chain 10 is wound (FIG. 2A).

  The sprocket 20 has a plurality of teeth 21, 21,... Formed at an equal pitch around a circular plate material, and a mounting hole 22 is formed on the axis C2. The teeth 21, 21... Are formed on the pitch circle PC. The sprocket 20 may have an odd or even number of teeth regardless of FIG.

  The cross-sectional shape in the tooth width L2 direction of the tooth bottom 21a of each tooth 21 of the sprocket 20 is as follows: a circular arc portion a2 having a convex curvature radius R4 at the central portion, and left and right straight portions b2, b2 smoothly connected to the circular arc portion a2. (FIG. 2B). Further, the arc portion a2 is continuous on the tooth surface of each tooth 21 from the root 21a to the linear tooth tip 21b. However, the arc portion a2 may be smoothly disappeared toward the tooth tip 21b during the period from the tooth bottom 21a to the tooth tip 21b.

  Each roller 11 of the roller chain 10 meshes with the teeth 21, 21... Of the sprocket 20 (FIG. 3). At this time, the convex portions b1 and b1 of the roller 11 are in symmetrical contact with the straight portions b2 and b2 of the tooth bottom 21a, and a gap G is formed between the tooth bottom 21a and the outer peripheral surface of the roller 11. The gap G is maximized in the axial center C1 direction of the roller 11, that is, in the central portion of the sprocket 20 in the tooth width L2 direction, and smoothly decreases toward both outer sides, and the convex portions b1, b1 of the roller 11 and the sprocket 20 It disappears at the contact positions f and f with the straight portions b2 and b2. The contact positions f and f are inside the maximum outer diameter portions e and e of the roller 11.

  Therefore, the impact force generated when the roller 11 collides with the tooth bottom 21a of the sprocket 20 acts in the direction of crushing the gap G, elastically deforms the roller 11, and causes slippage between the roller 11 and the tooth bottom 21a. (Arrows K1 and K1 in FIG. 3). Therefore, a part of the impact energy at the time of the collision between the roller 11 and the sprocket 20 is absorbed as distortion energy of the roller 11 or friction energy with the sprocket 20, and traveling noise due to impact sound can be reduced.

  FIG. 4 shows an example of actual measurement data of running noise of the chain drive device by the roller chain 10 and the sprocket 20. In FIG. 4, curve (1) is an actual measured value of running noise of the chain drive device of the present invention, and curve (2) uses the sprocket 20 used in the present invention and the drum-shaped roller 11x. It is an actual measurement value of traveling noise of a chain driving device (FIG. 5, hereinafter referred to as Comparative Example 1) combined with the roller chain 10x. Curve (3) is a measured value of traveling noise of a normal roller chain having a simple cylindrical roller and a chain driving device (hereinafter referred to as Comparative Example 2) using a sprocket compatible therewith.

  The roller 11x of Comparative Example 1 is formed into a symmetrical drum shape by uniformly increasing the outer diameter Dx from the central portion toward both ends (FIG. 5A), and the axial center C11 of the roller 11x is The cross-sectional shape on the radial plane passing therethrough is composed of a circular arc part a11 having a concave radius of curvature R11 at the central part, and left and right linear parts b11 and b11 smoothly connected to the circular arc part a11. In Comparative Example 1, the roller 11x and the tooth bottom 21a of the sprocket 20 are in contact with each other at both positions of the sprocket 20 (FIG. 5B).

  In the noise measurement test of FIG. 4, a microphone was installed 100 mm away from the drive-side sprocket, and the sound pressure level was measured when the drive shaft rotation speeds were 1125 rpm, 1450 rpm, and 1800 rpm, respectively. The horizontal axis in FIG. 4 is the rotational speed N (rpm) on the drive side, and the vertical axis is the sound pressure level P (dB).

  According to FIG. 4, the chain drive device of the present invention has a clear running noise reduction effect as compared with Comparative Example 1 and Comparative Example 2.

Other embodiments

  As the cross-sectional shape of the concave portion a1 and the convex portion b1 of the roller 11, a smooth function curve such as a quadratic curve other than an arc can be used. The sectional shape outside the maximum outer diameter portion e of each convex portion b1 may be a smooth function curve such as a quadratic curve other than an arc instead of an arc having a radius of curvature R3, or two or more arcs. May be combined. Therefore, in FIG. 1B, the concave portion a1 of the roller 11 uniformly increases the outer diameter D from the central portion toward both outer sides, and each convex portion b1 has the outer diameter D uniformly toward the outer side. The maximum outer diameter portion e can be formed smoothly, and the outer diameter D can be uniformly reduced from the maximum outer diameter portion e toward the outside.

  The cross-sectional shape of the tooth bottom 21a of the sprocket 20 may be a straight part parallel to the axial center C2 in the entire tooth width L2, and only the arc part a2 in FIG. 2B is parallel to the axial center C2. It is good also as a straight part. Further, the cross-sectional shape of the tooth bottom 21a can be such that the straight portions b2 and b2 are smooth curved portions using a function curve such as an arc. That is, in FIG. 2B, the cross-sectional shape of the tooth bottom 21a can be formed into a symmetrical mountain shape by uniformly reducing the distance d from the axis C2 from the central portion toward both outer sides. However, the outside here refers to the left-right direction with respect to the center in the direction of the tooth width L2. The cross-sectional shape of the tooth bottom 21a of the sprocket 20 is such that a gap G is formed between the outer peripheral surface of the roller 11 at the center portion in the tooth width L2 direction, and each convex portion b1 of the roller 11 has a maximum outer diameter portion. It is assumed that the position of e or the inside of the maximum outer diameter portion e is set so as to contact the tooth bottom 21a symmetrically.

  The present invention can be widely and suitably used for applications in which it is particularly required to reduce the running noise of the roller chain, for example, a chain drive device for a motorcycle.

C1, C2 ... shaft center a1 ... concave part b1 ... convex part b2 ... linear part e ... maximum outer diameter part D ... outer diameter d ... distance R1, R2, R3 ... radius of curvature L2 ... tooth width 10 ... roller chain 11 ... roller 20 ... Sprocket 21a ... Bottom

Claims (4)

It comprises a roller having a left and right symmetrical outer peripheral shape consisting of a concave portion at the central portion in the axial direction and convex portions that continue smoothly on both outer sides of the concave portion, and the concave portion is directed from the central portion toward both outer sides. The outer diameter is increased uniformly, and each convex portion increases the outer diameter uniformly toward the outside to form a smooth maximum outer diameter portion, and the outer diameter from the maximum outer diameter portion toward the outer side. The convex portion contacts the sprocket tooth bottom symmetrically, and a gap that smoothly decreases from the central portion in the axial direction toward both outer sides is formed between the outer periphery of the concave portion and the tooth bottom. The roller chain formed between and elastically deforming in a direction to crush the gap when colliding with a tooth bottom .   The cross-sectional shape of the concave portion is an arc having a concave curvature radius, and the cross-sectional shape of each convex portion is a convex curvature from the outer side of the concave portion to the maximum outer diameter portion and the outer side of the maximum outer diameter portion. The roller chain according to claim 1, wherein the roller chain is a circular arc having a radius.   A roller chain according to claim 1 or 2 and a sprocket around which the roller chain is wound, wherein the sprocket has an axial center with the cross-sectional shape of the tooth bottom extending from the center in the tooth width direction toward both outer sides. The chain driving device is characterized in that the distance from the ring is uniformly reduced to form a symmetrical mountain shape, and each convex portion is in contact with the tooth bottom inside the maximum outer diameter portion.   The chain driving device according to claim 3, wherein the convex portion is in contact with the tooth bottom at a symmetrical linear portion of a cross-sectional shape of the tooth bottom.

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