JPH0540348Y2 - - Google Patents

Description

[Detailed explanation of the idea] (b) Industrial application fields The present invention relates to a chain.

(b) Prior Art As an example of a prior art chain, there is one as shown in Fig. 4. Fig. 4 shows one link plate 50, and a chain is constructed by sequentially connecting such link plates 50 with locking joint pins 54 provided in pin holes 52. Locking joint pins 54
The pin hole 52 is formed of two pivot members 54a which are in contact with each other at their opposing surfaces having an arcuate cross section and pivot relative to each other.
The position of the swing member 5 is restricted.
4a comes into contact with the pin hole 52 at the portion indicated by the symbol C.

(c) Problems to be solved by the invention However, in the conventional chain as described above, stress concentration occurs near the contact portion of the pin hole 52 with the swinging member 54a, and durability may be insufficient. There is a problem. That is, since the pin hole 52 receives a force from the swinging member 54a at the C portion, it receives a tensile stress near the A point and a compressive stress near the B point. The link plate 50 is damaged due to fatigue, and the magnitude of stress amplitude is an important factor in fatigue failure in addition to the absolute value of stress. A relatively large stress amplitude is generated at the above-mentioned points A and B. This is because when the link plates 50 are bent, the contact points between the rocking members 54a of the rocker joint pins 54 change, and the distribution of the load acting on the pin holes 52 of the link plates 50 also changes. . Furthermore, since the radius of curvature is particularly small at point B, stress concentration tends to occur. The present invention aims to solve these problems.

A conventional chain that solves the above-mentioned problems is disclosed in Japanese Patent Application Laid-Open No. 59-99142. The chain shown here is composed of a link plate and a rocker joint pin, and the contact portion between the pin hole of the link plate and the rocker joint pin is both shaped to be flatter than a perfect circle. This is intended to increase the radius of curvature of the contact portion and reduce stress concentration.
However, in this case, since the pin hole of the link plate and the contact part of the rocker joint pin have the same shape, the pin hole and the rocker joint pin may be uniform due to variations in shape due to machining errors. There is a possibility that there is no surface contact, but rather a portion with a relatively small radius of curvature, or a single point. In such a case, stress concentration occurs, which also reduces the life of the chain.

The present invention aims to solve such problems.

(d) Means to solve the problem In this invention, the pin hole shape of the link plate is made non-perfect circular, the radius of curvature near the contact part with the locking joint pin is made large, and the part with the small radius of curvature is made as small as possible. The above problem is solved by moving away from the contact part. In other words, the pin hole provided in the link plate of the chain according to the present invention has a non-perfect circular shape that is deformed based on a perfect reference circle, and the circumference of the pin hole has a radius of curvature larger than that of the reference circle. Each 1/4 located inside the reference circle
Two contact arc parts with weak arcs adjacent to each other, an intermediate arc part that has a radius of curvature smaller than the reference circle and is inscribed in the reference circle, which connects the two contact arc parts, and an intermediate arc part on the opposite side of the intermediate arc part. To position,
Consists of a reference circle matching arc part that matches the reference circle, and two connecting arc parts that connect the contact arc part and the reference circle matching arc part, and the two pin holes provided in the link plate match the reference circle. The arc portions are arranged in opposite directions so that they are closest to each other. Further, the cross-sectional shape of the rocking member of the rocker joint pin, which faces the contact arc portion and the intermediate arc portion of the pin hole of the link plate, is a perfect circular arc with a diameter smaller than the reference circle mentioned above. It is sized to make contact with the contact arc portion.

(E) Function The reference circle corresponds to the circular part of the conventional pin hole. The radius of curvature of the contact arc portion is larger than the radius of the reference circle. Therefore, stress concentration does not occur in this vicinity. In addition, although the radius of curvature of the intermediate arc portion and the connecting arc portion is smaller than that of the reference circle, it is large enough to avoid stress concentration, and these portions are larger than the center portion of the contact arc portion. Since it is set away from the chain, it is not directly affected by the load distribution due to bending of the chain, and the stress amplitude is small.
As a result, the amplitudes of both the tensile stress and the compressive stress are reduced, and the fatigue strength of the link plate is improved. Further, since the locking joint pin always comes into contact with the two contact arc portions of the pin hole, contact at one point or contact at a portion with a small radius of curvature is reliably prevented.

(F) Embodiment FIG. 3 schematically shows a V-belt 50 using the chain of the present invention. The chain is formed into an endless ring by connecting link plates 10 having pin holes 11 at both ends successively by rocker joint pins 12. Rockard joint pin 1
2 is constituted by two swinging members 12a that swing in contact with each other on opposing surfaces having an arcuate cross section. This link plate 10 is connected to the friction block 14.
Friction block 1
4 is held against the chain. The friction block 14 has a tapered cross section for contacting the conical surface of the pulley.

FIG. 2 shows the link plate 10 alone, and FIG. 1 shows an enlarged view of the pin hole 11 of the link plate 10 and the swinging member 12a of the rocker joint pin 12. The pin hole 11 is not a perfect circle and is composed of six circular arc parts. That is, assuming a reference circle S shown by an imaginary line in FIG. 1, two contact arcuate portions 11 having a radius of curvature larger than the radius of the reference circle S are provided. The contact arc portions 11a each occupy a little less than 1/4 arc of the pin hole 11, and are located on the inner diameter side of the reference circle S. The two contact arc portions 11a are intermediate arc portions 1 with a radius of curvature smaller than the radius of the reference circle S.
1b. The apex of the intermediate arc portion 11b is inscribed in the reference circle S. Approximately 1/4 on the opposite side from the intermediate arc portion 11b
A reference circle matching circular arc portion 11c that occupies a small portion of the circular arc is provided. The reference circle matching arc portion 11c has a shape that matches the reference circle S. The reference circle matching arc portion 11c and the contact arc portion 11a are each smoothly connected by a connecting arc portion 11d. The radius of curvature of the connecting arc portion 11d is the reference circle S
is smaller than the radius of In addition, the connecting arc part 1
1d is located outside the reference circle S. As a result, a pin hole 11 as shown in FIG. 1 is formed, and the contact arc portion 11a comes into contact with the back surface of the rocking member 12a of the rocker joint pin 12. In addition, the link plate 10
The two pin holes 11 provided in the swinging member 12a
Since they receive forces in the tensile direction from each other, they are arranged in opposite directions as shown in FIG.

Swinging member 12a of rocker joint pin 12
The cross-sectional shape of the outer surface side is a perfect circular arc with a diameter slightly smaller than the reference circle S.

Since the radius of curvature of the two contact arcuate portions 11a with which the swinging member 12a comes into contact is large, no stress concentration occurs in these portions. Middle arc part 1
1b has a smaller radius of curvature than the contact arc portion 11a, but since it is provided at a position away from the contact point with the swinging member 12a, the swinging member 1
The influence of load fluctuations in 2a is alleviated, and the stress amplitude becomes small. Moreover, this intermediate circular arc portion 11b
The radius of curvature is also very large compared to point B of the conventional example shown in FIG. 4, which is very advantageous in terms of avoiding stress concentration. Furthermore, since the connecting arc portion 11d is also far away from the point of contact with the swinging member 12a, the stress amplitude is small. After all, by forming the pin holes 11 in such a shape, the amplitudes of tensile and compressive stresses are reduced, and the fatigue strength of the link plate 10 is improved.

(g) Effects of the invention As explained above, according to the invention, the pin hole of the link plate is made non-circular, the radius of curvature of the part of the rocker joint pin that contacts the swinging member is increased, and this By placing the part with a small radius of curvature caused by the locking joint pin away from the point of contact with the locking joint pin, stress concentration can be avoided and the effects of stress amplitude can be alleviated, improving the durability of the link plate. can be improved. Further, since the locking joint pin always comes into contact at two contact arc portions of the pin hole, contact at one point or contact at a portion with a small radius of curvature is prevented.

[Brief explanation of drawings]

Fig. 1 is an enlarged view of the pin hole of the link plate according to the embodiment of the present invention, Fig. 2 is a view showing the link plate, Fig. 3 is a view showing the chain to which the present invention is applied, and Fig. 4 is a view showing the pin hole of the link plate according to the embodiment of the present invention. It is a figure which shows the conventional link plate. 10...Link plate, 11...Pin hole, 1
1a...Contact arc portion, 11b...Intermediate arc portion, 11c...Reference circle matching arc portion, 11d...
Connection arc portion, 12... rocker joint pin, 12a... rocking member.

Claims (1)

[Claims for Utility Model Registration] An endless link plate is created by sequentially connecting a plurality of link plates with a rocker joint pin consisting of two rocking members that are able to swing in contact with each other on opposing surfaces having an arcuate cross section. In this chain, the pin hole provided in the link plate has a non-perfect circular shape that is deformed from a perfect circular reference circle, and the circumference of the pin hole has a radius of curvature larger than that of the standard circle. two contact arc parts adjacent to each other of a little less than 1/4 arc each located on the inside;
An intermediate arc part that connects the two contact arc parts and has a radius of curvature smaller than the reference circle and is inscribed in the reference circle, and a reference circle matching arc part that matches the reference circle and is located on the opposite side of the intermediate arc part. , two connecting arc parts that connect the contact arc part and the reference circle matching arc part, and the two pin holes provided in the link plate are arranged so that the reference circle matching arc parts are closest to each other. The cross-sectional shape of the swinging member of the rocker joint pin, which is arranged in the opposite direction to the above-mentioned reference circle and faces the contact arc portion and intermediate arc portion of the pin hole of the link plate, is a true circle with a smaller diameter than the reference circle mentioned above. A chain characterized in that it is an arc of a circle and has a size that makes contact with the contacting arc portion.