JPH07151192A - Chain for power transmission - Google Patents

Abstract

PURPOSE:To reduce the wear-oriented elongation, and suppress the deterioration of the fatigue strength and the strength of a pin and a link. CONSTITUTION:A plurality of link plates 4a where a pair of pin holes 3a are formed are arranged in the longitudinal direction and in the thickness direction, and turnably connected by pins 5 of approximately circular section inserted in the pin holes 3a, and guide link plates 6 are arranged on the outermost side of the link plates 4a to constitute a silent chain 1. The pin holes 3a of each link plate 4a of the non-guide link row which is the set of the link plates 4a arranged between the adjacent guide link plates 6, 6 are formed in approximately D-shape consisting of approximately U-shaped surfaces 10, 11 and a flat surface 12 connecting each end part, and a bush 15 of approximately U- shape which is arranged along the approximately U-shaped surfaces 10, 11 and where each end part abuts on the flat surface 12 is mounted in the pin hole 3a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power transmission chain, and more particularly to an improvement in a structure capable of reducing wear elongation, suppressing fatigue strength deterioration, and suppressing pin and link strength deterioration.

[0002]

2. Description of the Related Art For example, a silent chain has been widely used as a power transmission chain for automobiles and motorcycles. In this silent chain, as shown in FIGS. 14 and 15, the guide link plate 50
A guide link row 52, which is a set of link plates 51 arranged at the same longitudinal position (horizontal position in the figure), and a non-guide link, which is a set of link plates 51 arranged between adjacent guide link plates 50. A round pin type silent chain is proposed in which the row 53 is connected by a round pin 54.

By the way, in general, when the silent chain is used, the silent chain is repeatedly bent and extended with tension F applied thereto. Therefore, even in the round pin type silent chain, the link plate 5 is provided around the pin 54.
As the 1 rotates, the non-guide link row 5
The left and right pin holes 55 of each link plate 51 forming part 3
Wear is likely to occur between both outer side portions (see A portion in FIG. 15) and the pin sliding surface that slides with the outer side portions. Such wear increases the elongation of the entire chain, and if this elongation exceeds a certain allowable range, problems such as the chain riding on the teeth of the sprocket occur.

Therefore, as measures for suppressing such chain wear, the following improvements have been made conventionally. That is, (i) a material having a high wear resistance is used for both the pin and the link plate to perform heat treatment, and the surface finish accuracy of the pin hole and the pin of the link plate is improved. (Ii) Provide a liner on the pin sliding part of the pin hole of the link plate. (iii) A bush is provided on the pin sliding portion.

An example of the above (ii) is shown in FIGS. 16 to 20. In these drawings, roof tiles extending in the thickness direction of the link plate 4 are provided on the outer sides of the left and right round pins 54 that pass through the non-guide link rows 53 (that is, on the inner sides of the round pins 54 when viewed from the guide link rows 52). A liner 56 is provided. In addition, the left and right pin holes 58 of each link plate 51 forming the non-guide link row 53 (see FIG. 19).
Is composed of an arcuate hole 55a through which the round pin 54 is inserted, and an arcuate hole 57 which is formed so as to project outward in an arcuate shape and into which the roof tile liner 55 is mounted. The left and right pin holes 60 (see FIG. 20) of each link plate 51 that form the guide link row 52 are similarly formed with an arcuate hole 55b into which the round pin 54 is inserted and an inward arcuate projection 55b. It is composed of an arcuate hole 59 into which the roof tile liner 55 is mounted.

An example of the above (iii) is shown in FIGS. 21 to 23. Bushings 62 are press-fitted into the left and right pin holes 55c of each link plate 51 forming the non-guide link row 53, and the round pins 54 are slidably inserted into the bushes 62.

[0007]

In the example of (ii) above,
As shown in FIGS. 19 and 20, the pin holes 58 and 60 of each link plate 51 are both stepped holes, and the stepped portions B and C of each hole are the most in terms of strength of the link plate 51. Since it has to be arranged in a weak portion, stress concentration is likely to occur in the stepped portions B and C when tension is applied to the chain, and the fatigue strength is likely to decrease. Further, since the chain can be bent only at an angle until the pin hole stepped portion C of the link plate 51 (FIG. 20) on the guide link row 52 side comes into contact with the end surface of the liner 56, there is a limit in the bending angle. Not suitable for use with tensioners such as chains.

In the above example (iii), since the bush 62 is press-fitted into the pin hole 55c of the link plate 51 to prevent the bush 62 from rotating, the bush 62 is prevented.
In order to secure the strength of, it is necessary to increase the thickness to some extent. However, when the pin hole diameter is increased, the link strength is reduced, and when the pin diameter is decreased, the pin strength is insufficient. Further, the bush 58 is generally manufactured by winding a plate material in consideration of the manufacturing cost, but the joint portion 63 is likely to be distorted, and it is not easy to make it into a perfect circle. Further, it is difficult for the polishing media for barrel polishing to pass through the inner surface of the bush 58, so that the inner surface is not easily polished.

Further, in the above example (i), since the link plate is generally manufactured by punching with a press, there is a limit in improving the surface finish accuracy of the inner surface of the pin hole of the link plate. In addition, it is not easy to align the pin holes of a large number of linked link plates linearly in the pin longitudinal direction. Therefore, in this case, it is extremely difficult to secure a good sliding surface with the pin outer peripheral surface.

The present invention has been made in view of such circumstances, and provides a chain for power transmission capable of reducing wear elongation, suppressing deterioration of fatigue strength, and suppressing deterioration of strength of pins and links. The purpose is to do.

[0011]

In a power transmission chain according to the present invention, a plurality of link plates having a pair of pin holes are arranged in the longitudinal direction and the thickness direction and are inserted into the pin holes. In a power transmission chain in which a guide link plate is arranged on the outermost side of the link plate, the guide link being rotatably connected by a pin having a substantially circular cross section, the guide link being arranged at the same longitudinal position as the guide link plate. The pin holes of each link plate of at least one of the non-guide link rows arranged between the row and the adjacent guide link plates from the substantially semi-circular surface and the flat surface connecting both ends thereof. Is formed into a substantially D-shaped cross section, and has a substantially semi-arcuate cross section along the substantially semi-arcuate surface and both ends thereof contact the flat surface in the pin hole. It is characterized by wearing the Interview.

[0012]

In the present invention, the pin hole of each link plate of at least one of the guide link row and the non-guide link row is formed in a substantially D-shaped cross section, and
Since the bush along the substantially semi-arcuate surface is mounted in the pin hole, the wear of the pin and the link can be suppressed, and the wear elongation of the chain can be reduced.

Further, in this case, since the pin hole of the link plate is formed in a substantially D-shaped cross section, there is no stepped portion, and the stress concentration point is located at a position apart from the weakest portion of the link plate. As a result, the fatigue strength of the chain can be prevented from decreasing. Further, since both ends of the bush contact the flat surface of the pin hole to prevent the bush from rotating, it is not necessary to increase the thickness of the bush in order to press the bush into the pin hole. As a result, it is possible to prevent the strength of the pins and links from decreasing. further,
Since the bush is formed in a substantially semi-circular cross section, the polishing medium for barrel polishing, for example, can easily pass through the inner surface (pin sliding surface) of the bush. As a result, the inner surface of the bush can be easily polished, and the surface finish accuracy of the inner surface of the bush can be improved, so that the wear of the pin and the link can be further suppressed.

[0014]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 6 are views for explaining a silent chain according to an embodiment of the present invention. FIG. 1 is a partially cutaway plan view of the silent chain, FIG. 2 is a front view thereof, and FIG. 4 is an enlarged view of the link plate of the guide link row, FIG. 4 is an enlarged view of the link plate of the guide link row, FIG. 5 is an overall perspective view of the U-shaped bush in cross section, and FIG.

As shown in FIGS. 1 to 4, the silent chain 1 includes a pair of tooth portions 2 and a pair of pin holes 3 (3a, 3a,
3b) and link plate 4 (4a, 4b) formed with
Are arranged in the longitudinal direction (horizontal direction in FIG. 1) and thickness direction (vertical direction in FIG. 1) of the link plate 4, and the connecting pin 5 having a substantially circular cross section is inserted into the pin hole 3 of these link plates 4. Then, each link plate 4 is pivotally connected to each other, a guide link plate 6 is arranged on the outermost side of the link plate 4, and the end portion of the connecting pin 5 is fixed to the guide link plate 6 by caulking or the like. It has a structure.

As a result, the silent chain 1 is
A guide link row 7 including a set of link plates 4b arranged at the same longitudinal position as the guide link plate 6.
And a non-guide link row 8 composed of a set of link plates 4a arranged between adjacent guide link plates 6. Here, a so-called two-layered link plate array in which two link plates 4 are stacked in the thickness direction is taken as an example.

As shown in FIG. 3, the pin hole 3a of the link plate 4a of the non-guide link row 8 is U-shaped by the semi-circular surface 10 and the semi-circular surface 10 extending in the tangential direction thereof. It is composed of a flat surface 11 forming a surface (a substantially semi-circular surface) and a flat surface 12 connecting both ends of the flat surface 11, that is, the pin hole 3a is formed in a substantially D-shaped cross section. ing. Further, the pin hole 3a is preferably orthogonal to the direction in which its center line (dashed line) intersects the inner flank surface 14 of the link plate 4a (that is, the flat surface 12 is substantially parallel to the inner flank surface 14). ) Is inclined and formed. The pin hole 3b of the link plate 4b of the guide link row 7 is formed in a substantially circular shape (see FIG. 4).

A bush 15 having a U-shaped cross section (substantially semi-arcuate) as shown in FIGS. 5 and 6 is inserted into the pin hole 3a of the link plate 4a of the non-guide link row 8 (FIG. 5). 1, see FIG. 2). The U-shaped surface 15a of the bush 15 is along the U-shaped surface of the pin hole 3a, and both ends 15b thereof are in contact with the flat surface 12 of the pin hole 3a. The length s of the bush 15 is approximately the same as the thickness of the two link plates 4a combined.

Next, the function and effect of the above embodiment will be described. When the silent chain 1 is used, it bends and stretches repeatedly under tension, but in this case,
As described above, the pin holes 3a of each link plate 4a of the non-guide link row 8 are formed in a substantially D-shaped cross section, and the bushes 15 along the U-shaped surfaces 10 and 11 are mounted in the pin holes 3a. The pin 5 and the link plate 4
The wear of a can be suppressed, and as a result, the wear elongation of the silent chain 1 can be reduced.

Since the pin hole 3a of the link plate 4a is formed in a substantially D-shaped cross section, there is no stepped portion, and the stress concentration point (corner of the pin hole 3a) is at the link plate 4.
It is arranged at a position deviating from the weakest part of a, whereby the reduction of the fatigue strength of the silent chain 1 can be suppressed. Further, since both ends 15b of the bush 15 are brought into contact with the flat surface 12 of the pin hole 3a to prevent the bush 15 from rotating, it is not necessary to press the bush 15 into the pin hole 3a. Since it is not necessary to increase the thickness t, it is possible to suppress the reduction in strength of the pin 5 and the link plate 4a.

Further, since the bush 15 is formed in a U-shaped cross section, the polishing medium for barrel polishing, for example, can easily pass through the inner surface (pin sliding surface) 15c of the bush 15. As a result, the bush inner surface 15c can be easily polished, and the surface finishing accuracy of the bush inner surface 15c can be improved.
The wear of a can be suppressed further. By forming the bush 15 in a U-shaped cross section, the bush 15 can be manufactured by various processing methods such as drawing and bending, and the manufacturing is facilitated.

Further, since the bush 15 has a U-shaped cross section, the gap portion 18 (see FIG. 2) generated when the pin 5 is inserted into the bush 15 acts as an oil sump. This makes it possible to spread the lubricating oil over the sliding surfaces of the pin 5 and the bush 15, and further suppress the wear of the pin 5 and the link plate 4a.

Further, since the so-called two-layered link plate array in which the two link plates 4 are stacked in the thickness direction is arranged, the parallelism between the bush inner surface 15c and the pin 5 can be obtained,
As a result, a wider sliding surface can be secured and uneven wear of the pin 5 can be prevented.

By mounting the bush 15 only on the link plate 4a of the non-guide link row 8, the pin hole 3b of the link plate 4b of the guide link row 7 can be made substantially circular, and the pin of the link plate 4b can be made. Hole 3b
About stress concentration can be prevented. Moreover, by making the pin hole 3b substantially circular, the parallelism between the bush inner surface 15c and the pin 5 can be further improved. Furthermore, the amount of rotation of each link plate 4 around the pin 5 can be increased, and thus the degree of bending of the chain can be increased, and the silent chain 1 can also be applied to, for example, engine timing.

Next, a silent chain according to another embodiment of the present invention is shown in FIG. 7, the same reference numerals as those in FIG. 1 denote the same or corresponding parts. This silent chain 20 is different from the silent chain 1 of FIG. 1 in addition to the fact that the link plate array is a single stack, and in addition, the plates 21 for preventing slipping out are arranged on both outer sides of the guide link plate 6, This is the point where the plate 21 is engaged with the end of the pin 5. Therefore, in this case, since the pin 5 is not fixed to the guide link plate 6 by caulking and can rotate freely, a sliding surface can be secured around the entire circumference of the pin 5 and uneven wear of the pin 5 can be prevented. It is possible.

Since the pin 5 freely rotates in this way, when the present invention is applied to this type of silent chain 20, from the viewpoint of wear prevention, the non-guide link row 8 is used.
It is preferable that not only the link plate 4a but also the link plate 4b of the guide link row 7 is formed with each pin hole having a substantially D-shaped cross section and a bush having a U-shaped cross section is inserted into the pin hole. It is also possible to apply the characteristic part of the present invention to only one of the link strings.

In the above embodiment, the tilt angle of the pin hole 3a has been described as an example in which the center line is tilted in the direction intersecting with the inner flank surface 14 of the link plate 4a (see the alternate long and short dash line in FIG. 3). ), The pin hole 3a
The inclination angle of is not limited to this. With respect to the tension of the chain, any inclination angle may be obtained as long as a sliding surface as a part of the cylindrical inner surface is obtained on the bush inner surface (pin sliding surface) between the pin outer peripheral surface (Fig. 8, (See FIG. 9).

Further, the bush 15 is not limited to the one having a U-shaped cross section as shown in FIG. 6, but as long as it has at least a semi-circular surface, a substantially ring-shaped cross section in which a part of a cylinder is cut out. It may have a shape (see FIG. 10), a horseshoe shape (see FIG. 11), or an asymmetric horseshoe shape (see FIG. 12). Each of them has a substantially semi-circular pin sliding surface 18.

Regarding the link plate arrangement, the application of the present invention is not limited to the two-ply arrangement or the one-ply arrangement, but the present invention can be applied to any other link-plate arrangement such as a multi-ply arrangement.

It is also possible to use a so-called random array link plate as the link plate 4 of the above embodiment. In this link plate, the inner flank surface is protruded in an arc shape unlike a normal linear flank surface (see the inner flank surface 14 in FIGS. 3 and 4), and such a link plate is randomly included. By applying the present invention to the chain, it is possible to reduce the wear elongation, it is possible to suppress the decrease in fatigue strength,
It is possible to realize a random chain that can prevent the strength of pins and links from decreasing.

Furthermore, in the above embodiment, an example in which the present invention is applied to a silent chain is shown, but the present invention is a CVT.
(Continuously Variable Transmission) chain (see, for example, Japanese Patent Application Laid-Open No. 1-145447) can be similarly applied. FIG. 13 shows only the link plate of the CVT chain described in the above publication. Similar to FIG. 8, a pin hole 31 having a substantially D-shaped cross section is formed in the link plate 30, and a bush 32 having a U-shaped cross section is inserted into the pin hole 31 and is inserted in the bush 32. A connecting pin 33 having a substantially circular cross section is inserted. As described above, by applying the present invention to a CVT chain, it is possible to realize a CVT chain that can reduce wear elongation, suppress fatigue strength deterioration, and suppress strength deterioration of pins and links.

[0032]

As described above, according to the power transmission chain of the present invention, the pin hole of each link plate of at least one of the guide link row and the non-guide link row has a substantially D-shaped cross section. Since the bush is formed along the substantially semi-circular surface in the pin hole, wear of the pin and the link can be suppressed, and wear elongation of the chain can be reduced.

Further, in this case, since the pin hole of the link plate is formed in a substantially D-shaped cross section, there is no stepped portion and the stress concentration point is located at a position deviated from the weakest portion of the link plate. Since they are arranged, this has the effect of suppressing a decrease in the fatigue strength of the chain. Also,
Since both ends of the bush contact the flat surface of the pin hole to prevent the bush from rotating, it is not necessary to increase the thickness of the bush in order to press the bush into the pin hole. ， There is an effect that can suppress the decrease of link strength.

[Brief description of drawings]

FIG. 1 is a partial cutaway plan view of a silent chain according to an embodiment of the present invention.

FIG. 2 is a partially cutaway front partial view of the silent chain.

FIG. 3 is an enlarged view of a link plate of a non-guide link row that constitutes the silent chain.

FIG. 4 is an enlarged view of a link plate of a guide link row that constitutes the silent chain.

FIG. 5 is an overall perspective view of a bush having a U-shaped cross section attached to the link plate of the non-guide link row.

FIG. 6 is a cross-sectional view of the bush having a U-shaped cross section.

FIG. 7 is a plan partial view of a silent chain according to another embodiment of the present invention.

FIG. 8 is a view showing a modified example of pin holes formed in the link plate of the non-guide link row.

FIG. 9 is a diagram showing a modification of pin holes formed in the link plate of the non-guide link row.

FIG. 10 is a view corresponding to FIG. 6 showing a modified example of the bush having a U-shaped cross section.

FIG. 11 is a view corresponding to FIG. 6 showing a modified example of the bush having a U-shaped cross section.

FIG. 12 is a view corresponding to FIG. 6 showing a modified example of the bush having a U-shaped cross section.

FIG. 13 is a diagram showing an example in which the present invention is applied to a CVT chain.

FIG. 14 is a view corresponding to FIG. 1 of a conventional silent chain.

FIG. 15 is a front view thereof.

FIG. 16: FIG. 1 of a conventional silent chain with liner
It is a figure equivalent to.

FIG. 17 is a front view thereof.

FIG. 18 is an overall perspective view of the liner.

FIG. 19 is an enlarged view of a link plate of a non-guide link row that constitutes the liner-containing silent chain.

FIG. 20 is an enlarged view of a link plate of a guide link row forming the liner-containing silent chain.

FIG. 21 is a view of a conventional silent chain with bushes.
It is a figure equivalent to.

FIG. 22 is a front view thereof.

FIG. 23 is an overall perspective view of the bush.

[Explanation of symbols]

 1 Silent chain 3, 3a, 3b Pin hole 4, 4a, 4b Link plate 5 Connecting pin 6 Guide link plate 7 Guide link row 8 Non-guide link row 10, 11 U-shaped surface (substantially semi-arcuate surface) 12 Flat surface 15 bush 15b both ends

Claims (1)

[Claims] 1. A plurality of link plates having a pair of pin holes are arranged in the longitudinal direction and the thickness direction, and
In a power transmission chain in which a guide link plate is arranged on the outermost side of the link plate, which is rotatably connected by a pin having a substantially circular cross section inserted in the pin hole, the same longitudinal position as the guide link plate. At least one of the non-guide link rows arranged between the guide link rows arranged adjacent to each other and the non-guide link rows adjacent to each other. A bush having a substantially D-shaped cross-section formed of flat surfaces for connecting the parts, and having a substantially semi-arcuate cross section along the substantially semi-arcuate surface in the pin hole and both ends of which abut on the flat surface. A chain for power transmission, which is equipped with.