JP2005299755A - Power transmission chain and power transmission device equipped therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power transmission chain with a link having a relatively shorter connection pitch and a link having a relatively longer connection pitch, having improved practical strength and durability. <P>SOLUTION: The shorter link 21 and the longer link 22 are connected to each other using first and second pins 3, 4 corresponding to each other. A value for the surface hardness of the small shorter link 21 is greater than a value for the surface hardness of the large longer link 22 having high strength, and so the strength thereof is similar to that of the longer link 22. The links 21, 22 each have sufficient strength. As a result, the chain 1 has greatly improved practical strength and durability. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a power transmission chain and a power transmission device including the power transmission chain.

An endless power transmission chain used in a power transmission device such as a pulley-type continuously variable transmission (CVT) of an automobile typically has a plurality of links arranged in the chain traveling direction and adjacent to the chain traveling direction. They are connected with corresponding pins. Some of these power transmission chains use links with long connection pitch intervals and short links (for example, see Patent Document 1).
JP-A-7-167224

A link having a long connection pitch is larger than a link having a short connection pitch, and therefore has a higher strength.
The present invention has been made under such a background, and an object thereof is to provide a power transmission chain capable of further improving practical strength and durability and a power transmission device including the power transmission chain.

  In order to achieve the above object, the present invention provides a power transmission chain that includes a plurality of links arranged in a chain traveling direction, and the corresponding links are connected to each other using a connecting means including a pair of pins that are in rolling contact with each other. In the above, the plurality of links include a plurality of links having different connection pitches, and a link having a relatively short connection pitch has a surface hardness, a wall thickness, and a material strength as compared with a link having a relatively long connection pitch. At least one of these is made larger.

According to the present invention, a small link having a relatively short connection pitch can ensure the same strength as a large high-strength link having a relatively long connection pitch. Therefore, each link can be provided with sufficient strength, and the practical strength and durability of the chain can be significantly improved.
In the present invention, the link having a relatively short connection pitch may have a shorter total length in the chain traveling direction than a link having a relatively long connection pitch. In this case, the short link can be made lighter, and the centrifugal force generated in the chain when the chain is driven can be remarkably reduced. As a result, the load acting on the chain can be reduced and the durability can be further improved.

In the present invention, the Rockwell hardness HRC of the surface of the link having a relatively short connection pitch may be 3 or more higher than the Rockwell hardness HRC of the surface of the link having a relatively long connection pitch. In this case, a link having a relatively short connection pitch can have sufficient strength.
In the present invention, the plurality of links include first and second links, and each of the links has a front through hole and a rear through hole arranged in the front and rear in the chain traveling direction, and the pair of pins is A first pin press-fitted and fixed in the front through hole of the first link and movably fitted in the rear through hole of the second link, and movably fitted in the front through hole of the first link And a second pin fixed to the rear through-hole of the second link.

In this case, for example, when the first pin comes into contact with the sheave surface of the pulley and transmits power, the second pin rolls in contact with the first pin and moves in the length direction of the links. Bending is enabled, and the first pin hardly rotates with respect to the sheave surface, so that friction loss can be reduced and high transmission efficiency can be ensured.
The present invention also provides a first pulley and a second pulley each having a pair of conical sheave surfaces facing each other, and the power that is wound between these pulleys and transmits power by contacting the sheave surfaces. And a transmission chain. In this case, it is possible to realize a power transmission device that can transmit extremely large power and has excellent durability.

Preferred embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a perspective view schematically showing a configuration of a main part of a power transmission chain (hereinafter simply referred to as a chain) for a chain type continuously variable transmission according to an embodiment of the power transmission chain of the present invention. . FIG. 2 is a cross-sectional plan view of the main part of the chain shown in FIG. 3A is a cross-sectional view taken along the line II-II in FIG. 2, and FIG. 3B is a cross-sectional view taken along the line III-III in FIG. 3A and 3B show the straight portion of the chain 1. FIG.

  1 and 2, the chain 1 includes a short link 21 (a link having a relatively short connection pitch) and a long link 22 (a link having a relatively long connection pitch) as a plurality of links having different connection pitches. ), And the first row 51, the second row 52, and the third row 53 as a plurality of link rows arranged in the chain traveling direction X (hereinafter also simply referred to as “traveling direction”) are in rolling contact with each other. And connecting means 20 including first and second pins 3 and 4 as a pair of pins.

  3A and 3B, each of the short link 21 and the long link 22 is formed of steel or the like, and has a plate shape having substantially the same thickness. Each of the short link 21 and the long link 22 includes a front end portion 7 and 14 and a rear end portion 8 and 15 as a pair of end portions arranged in front and rear in the chain traveling direction X, and the corresponding front end portion 7 and 14 and the rear end portion. 8 and 15 are formed with corresponding front through holes 9 and rear through holes 10.

  In plan view, the connecting pitch P1 of the short links 21 refers to the distance between the connecting means 20 adjacent to each other in the short links 21. Specifically, in the straight portion of the chain 1, the first and A contact line T1 in which the second pins 3 and 4 are in contact with each other (in the cross section shown in FIG. 3A, the contact line T1 is represented as a point), and the first and second in the rear through-hole 10 Are defined as a distance between contact pins T2 (in the cross section shown in FIG. 3A, the contact lines T2 are represented as dots) with which the pins 3 and 4 are in contact with each other.

  Further, in the plan view, the connection pitch P2 of the long links 22 refers to the distance between the connecting means 20 adjacent to each other in the long links 22. Specifically, in the straight part of the chain 1, the connection pitch P2 of the long links 22 A contact line T3 in which the first and second pins 3 and 4 are in contact with each other (in the cross section shown in FIG. 3B, the contact line T3 is represented as a point); It is defined as a distance between contact lines T4 (second contact lines T4 are represented as dots in the cross section shown in FIG. 3B) where the second pins 3 and 4 are in contact with each other.

  With respect to the traveling direction X, the total length L1 of the short link 21 is shorter than the total length L2 of the long link 22 (L1 <L2). Specifically, the connection pitch P1 of the short links 21 is shorter than the connection pitch P2 of the long links 22 (P1 <P2), and the column between the through holes 9 and 10 of the short links 21 in the traveling direction X. The width of the portion 11 is made shorter than the width of the column portion 12 between the through holes 9 and 10 of the long link 22.

  Further, with respect to the traveling direction X, the distance L3 between the end surface 7a of the front end portion 7 of the short link 21 and the peripheral surface of the front through hole 9 of the short link 21 is the same as the end surface 14a of the front end portion 14 of the long link 22 It is shorter than the distance L4 between the long link 22 and the peripheral surface of the front through hole 9 (L3 <L4). Further, with respect to the traveling direction X, the distance L5 between the end surface 8a of the rear end portion 8 of the short link 21 and the peripheral surface of the rear through hole 10 of the short link 21 is the end surface 15a of the rear end portion 15 of the long link 22. And a distance L6 between the long link 22 and the peripheral surface of the rear through-hole 10 (L5 <L6).

  Referring to FIG. 2 again, the value of the surface hardness of the short link 21 is made larger than the value of the surface hardness of the long link 22. Specifically, the Rockwell hardness HRC of the surface of the short link 21 is set to 48, for example, and the Rockwell hardness HRC of the surface of the long link 22 is set to 45, for example. Thus, the Rockwell hardness HRC of the surface of the short link 21 as the link with the shortest connection pitch is 3 in comparison with the Rockwell hardness HRC of the surface of the long link 22 as the link with the longest connection pitch. It is high.

The hardness difference between the short link 21 and the long link 22 is provided as follows when the chain 1 is manufactured. That is, for example, both the short link 21 and the long link 22 are quenched under the same conditions, but by increasing the tempering temperature of the short link 21, a difference in hardness is provided between them.
Each of the first to third columns 51 to 53 includes the short link 21 or the long link 22. Specifically, each of the first to third columns 51 to 53 includes a plurality of (for example, eight) short links 21 or long links 22 arranged in the chain width direction W, and each link in the same column. 21 and 22 are aligned in the advancing direction X position. For example, the first column 51 includes the long link 22 as the first link. The second column 52 includes the short link 21 as the second link. Third row 53 includes long link 22.

  A plurality of connecting means 20 are provided. Both ends of the first pin 3 of each connecting means 20 are connected to both ends of the chain width direction W from the links (for example, the short links 21 at both ends of the second row 52 in the chain width direction W). Power transmission surfaces 5 and 6 for contacting the sheave surface are provided on both end surfaces of the first pin 3, respectively. Since each first pin 3 directly contributes to power transmission by its power transmission surfaces 5 and 6, it is made of a high-strength material such as bearing steel (for example, SUJ2). The second pin 4 (also referred to as a strip or an interpiece) of each connecting means 20 is a rod-like body formed slightly shorter than the first pin 3 so as not to contact the sheave surface.

The corresponding short links 21 and long links 22 in the corresponding first to third rows 51 to 53 are connected to each other using the first and second pins 3 and 4 of the corresponding connecting means 20. It has become.
Specifically, as shown in FIGS. 2, 3 (a), and 3 (b), after the front through hole 9 of the long link 22 in the first row 51 and the short link 21 in the second row 52. The through holes 10 correspond to each other side by side in the chain width direction W, and the first and second rows 51 are formed by the first and second pins 3 and 4 that pass through these through holes 9 and 10. , 52 corresponding long links 22 and short links 21 are connected to each other such that they can be bent in the length direction.

  The first pins 3 are press-fitted and fixed (fitted) into the front through-holes 9 of the corresponding short links 21 and long links 22 so that relative rotation with respect to these short links 21 and long links 22 is restricted and corresponding. The short link 21 and the long link 22 are loosely fitted into the rear through-hole 10 by, for example, loose fitting, and can be moved relative to the short link 21 and the long link 22.

The first pin 3 is, for example, press-fitted and fixed to the front through-hole 9 of each long link 22 in the first row 51 to restrict relative rotation of each long link 22 in the first row 51 and second. The short links 21 of the second row 52 are loosely fitted in the rear through holes 10 so that the relative movement of the second links 52 with respect to the short links 21 is possible.
Similarly, the front through-holes 9 of the short links 21 in the second row 52 are aligned with the rear through-holes 10 of the long links 22 in the third row 53 in the chain width direction W. Corresponding short links 21 and long links 22 in the second and third rows 52 and 53 are connected to each other by the first pin 3 to be inserted. In this case, the first pin 3 is press-fitted and fixed in the front through-hole 9 of each short link 21 in the second row 52 and loosely fitted in the rear through-hole 10 in each long link 22 in the third row 53. Has been.

  The second pins 4 are press-fitted and fixed (fitted) into the rear through-holes 10 of the corresponding short links 21 and long links 22 so that relative rotation with respect to these short links 21 and long links 22 is restricted and corresponding. The front through-holes 9 of the short links 21 and the long links 22 are loosely fitted, for example, by loose fitting so that they can be moved relative to the short links 21 and the long links 22.

For example, the second pin 4 is loosely fitted into the front through-hole 9 of each long link 22 in the first row 51 and can be relatively moved with respect to each long link 22 in the first row 51. The relative rotation of each short link 21 in the second row 52 with respect to each short link 21 in the second row 52 is restricted by being press-fitted into the rear through-hole 10.
Similarly, the second pins 4 are loosely fitted in the front through holes 9 of the respective short links 21 in the second row 52 so that they can be moved relative to the respective short links 21 in the second row 52. The third through-holes 53 of the third row 53 are press-fitted and fixed in the rear through-holes 10 to restrict relative rotation of the third row 53 with respect to the long links 22.

  A link unit 13 as a module for the endless chain 1 is formed by the first to third rows 51 to 53. A plurality of link units 13 are arranged side by side in the chain traveling direction X (only one link unit 13 is shown in FIG. 2). And the corresponding short link 21 and long link 22 of the corresponding 1st-3rd row | line | columns 51-53 of the two link units 13 adjacent to the chain advancing direction X are mutually connected. The link units 13 are sequentially connected along the traveling direction X to form the endless chain 1 as a whole.

  Specifically, the front through hole 9 of each long link 22 in the third row 53 of the link unit 13 and the other link unit 13 (not shown) adjacent to one side (left side in FIG. 2) of the chain traveling direction X. The rear through holes 10 of the long links 22 in the first row 51 are arranged so as to correspond to each other. Then, the first pin 3 is press-fitted and fixed to the front through hole 9 of each long link 22 in the corresponding third row 53, and is inserted into the rear through hole 10 in each long link 22 in the corresponding first row 51. Loose fit. Further, the second pin 4 is loosely fitted into the front through hole 9 and is press-fitted and fixed into the rear through hole 10.

  Further, the third through-holes of other link units 13 (not shown) adjacent to the rear through-holes 10 of the long links 22 in the first row 51 of the link units 13 and the other (right side in FIG. 2) in the chain traveling direction X. The front through holes 9 (not shown) of the long links 22 in the row 53 are arranged so as to correspond to each other. Then, the first pins 3 are loosely fitted into the rear through holes 10 of the corresponding long links 22 in the corresponding first row 51 and are inserted into the front through holes 9 of the corresponding long links 22 in the corresponding third row 53. Press fit. Further, the second pin 4 is press-fitted into the rear through hole 10 and is loosely fitted into the front through hole 9.

  With the above configuration, when the chain is driven, the second pin 4 includes at least one of rolling and sliding contact (rolling contact and sliding contact) relative to the corresponding first pin 3 adjacent in the chain traveling direction X. Contact). The rolling contact component is large, the sliding contact component is small, the first pin 3 is hardly rotated with respect to the sheave surface of the pulley, the friction loss is reduced, and high transmission efficiency can be ensured.

Further, by changing the connection pitch P1 of the short links 21 and the connection pitch P2 of the long links 22, the generation period of the contact sound when the first pin 3 contacts the sheave surface of the pulley during the chain drive is changed. Can be made. Thereby, it is possible to prevent the above contact sound from resonating and extremely reduce the chain drive sound.
Furthermore, compared with the conventional chain using only the long link as the link, the chain 1 according to the present embodiment uses the short link 21 having a shorter connection pitch as a part, so that the average connection pitch of the chain 1 is reduced. The value can be shortened, and the number of the first pins 3 that can be engaged with the sheave surface of the pulley at a time can be increased. Thereby, compared with the said conventional chain, the chain 1 of this Embodiment can reduce the load per 1st pin 3 (pin which contacts a sheave surface), and makes an allowable transmission load larger. In addition, the chain drive sound caused by the contact between the first pin 3 and the sheave surface can be significantly reduced.

  As described above, according to the present embodiment, the small short link 21 has a larger surface hardness value than the large high-strength long link 22. Since the Rockwell hardness HRC of the surface of the short link 21 is 3 higher than the Rockwell hardness HRC of the surface of the long link 22, the same strength as that of the long link 22 can be secured. Therefore, each link 21 and 22 can be given sufficient strength, and the practical strength and durability of the chain 1 can be significantly improved.

Further, since the total length L1 of the short link 21 is shorter than the total length L2 of the long link 22 (L1 <L2), the short link 21 can be made lighter, and the centrifugal force generated in the chain 1 when the chain is driven is significantly reduced. can do. As a result, the load acting on the chain 1 can be reduced and the durability can be further improved.
Further, when the first pin 3 engages with the sheave surface and transmits power, the second pin 4 rolls against the first pin 3 and moves in contact with the corresponding one of the adjacent links 21, 22. Since bending in the longitudinal direction is possible, the first pin 3 hardly rotates with respect to the sheave surface, and friction loss can be reduced to ensure high transmission efficiency.

In addition, the work for increasing the surface hardness value of the short link 21 to be larger than the surface hardness value of the long link 22 can be performed in a heat treatment step usually included in chain manufacture, and is inexpensive.
In the above embodiment, the Rockwell hardness HRC of the surface of the short link 21 may be less than 3 or higher than 3 compared to the Rockwell hardness HRC of the surface of the long link 22. .

Moreover, although the structure which makes the value of the surface hardness of each short link 21 larger than the value of the surface hardness of each long link 22 was replaced with this, for example, Fig.4 (a) and FIG.4 (b) As shown, the thickness L7 of each short link 21 may be larger than the thickness L8 of each long link 22 (L7> L8).
Further, the material strength (strength per unit volume) of each short link 21 may be larger than the material strength (strength per unit volume) of each long link 22. In this case, each short link 21 is formed of, for example, spring steel (SUP10), and each long link 22 is formed of, for example, carbon steel (S58C).

Further, in each of the above embodiments, the surface hardness, the wall thickness L7, and the material strength of each short link 21 are either compared with the corresponding surface hardness, wall thickness L8, and material strength of each long link 22. Only two may be enlarged, or all three may be enlarged.
Moreover, in each said embodiment, the short link 21 may be arrange | positioned only in any one of the 1st and 3rd row | line | columns 51 and 53, and any of the 1st-3rd row | line | columns 51-53. Or may be arranged in two rows. Further, the arrangement pattern of the short links 21 with respect to the traveling direction X includes at least one of a regular pattern and an irregular pattern. That is, the arrangement pattern of the short links 21 may include only a regular pattern, may include a regular pattern and an irregular pattern, or may include only an irregular pattern. The same applies to the arrangement pattern of the long links 22.

Furthermore, you may provide three or more types of links from which a connection pitch differs. In this case, at least one of the surface hardness, the wall thickness, and the material strength of the link having a short connection pitch is increased as compared with the link having a long connection pitch.
Further, the number of corresponding short links 21 and long links 22 in the first to third columns 51 to 53 may be 7 or less, respectively, or 9 or more. Further, in each of the above-described embodiments, the case where only the first pin 3 contacts the sheave surface and transmits power is shown, but not limited to this, both the first and second pins 3 and 4 It can also be applied to the case where power is transmitted in contact with the sheave surface.

  FIG. 5 is a perspective view schematically showing a main configuration of a so-called chain-type continuously variable transmission (hereinafter also simply referred to as a continuously variable transmission) according to an embodiment of the power transmission device of the present invention. Referring to FIG. 5, the continuously variable transmission according to the present embodiment is mounted on a vehicle such as an automobile, and includes a drive pulley 60 made of metal (such as structural steel) as a first pulley. A driven pulley 70 made of metal (structural steel or the like) as a second pulley, and an endless chain 1 wound around these pulleys 60 and 70 are provided. In addition, the chain 1 in FIG. 5 has shown a partial cross section for easy understanding.

  6 is a partially enlarged sectional view of the drive pulley 60 (driven pulley 70) and the chain 1 of the chain type continuously variable transmission shown in FIG. Referring to FIGS. 5 and 6, drive pulley 60 is attached to an input shaft 61 that is connected to a vehicle drive source so as to be able to transmit power, and includes a fixed sheave 62 and a movable sheave 63. The fixed sheave 62 and the movable sheave 63 have a pair of sheave surfaces 62a and 63a that face each other. The sheave surfaces 62a and 63a include conical inclined surfaces. A groove is defined between the sheave surfaces 62a and 63a, and the chain 1 is held with a strong pressure by the groove.

  Further, a hydraulic actuator (not shown) for changing the groove width is connected to the movable sheave 63, and the movable sheave 63 is moved in the axial direction of the input shaft 61 (the left-right direction in FIG. 6) at the time of shifting. By changing the width of the groove, the chain 1 can be moved in the radial direction of the input shaft 61 (the vertical direction in FIG. 6), and the winding radius (effective radius) of the chain 1 with respect to the input shaft 61 can be changed. It has become.

  On the other hand, the driven pulley 70 is attached to an output shaft 71 connected to a drive wheel (not shown) so as to be able to transmit power, and, like the drive pulley 60, forms a groove for sandwiching the chain 1 with a strong pressure. There are provided a fixed sheave 72 and a movable sheave 73 having sheave surfaces 72a and 73a, respectively. A hydraulic actuator (not shown) is connected to the movable sheave 73 of the driven pulley 70 in the same manner as the movable sheave 63 of the drive pulley 60, and the groove width is changed by moving the movable sheave 73 during shifting. Thereby, the chain 1 is moved so that the winding radius (effective radius) of the chain 1 with respect to the output shaft 71 can be changed.

  In the continuously variable transmission according to the present embodiment configured as described above, for example, a continuously variable transmission can be performed as follows. That is, when the rotation of the output shaft 71 is decelerated, the groove width of the drive pulley 60 is increased by the movement of the movable sheave 63, and the power transmission surfaces 5, 6 at both ends of the first pin 3 of the chain 1 are conical. Under boundary lubrication (a lubrication state in which part of the contact surface is in direct contact with the microprojections and the remaining part is in contact with the lubricating oil film) toward the inner direction of the sheave surfaces 62a and 63a (downward in FIG. 6). The sliding radius of the chain 1 around the input shaft 61 is reduced while sliding. On the other hand, in the driven pulley 70, the groove width is reduced by the movement of the movable sheave 73, and the power transmission surfaces 5 and 6 of the first pin 3 of the chain 1 are moved outward from the conical sheave surfaces 72 a and 73 a (FIG. 6). The winding radius of the output shaft 71 of the chain 1 is increased while making sliding contact under boundary lubrication conditions.

  On the contrary, when the rotation of the output shaft 71 is increased, the groove width of the drive pulley 60 is reduced by the movement of the movable sheave 63, and the power transmission surfaces 5, 6 of the first pin 3 of the chain 1 are conical. The wrapping radius of the chain 1 with respect to the input shaft 61 is increased while making sliding contact under boundary lubrication conditions toward the outer side of the sheave surfaces 62a and 63a. On the other hand, in the driven pulley 70, the groove width is increased by the movement of the movable sheave 73, and the power transmission surfaces 5 and 6 of the chain 1 are slid under boundary lubrication conditions toward the inner side of the conical sheave surfaces 72a and 73a. The winding radius of the output shaft 71 of the chain 1 is reduced while making contact.

As described above, according to the present embodiment, it is possible to realize a power transmission device that is excellent in transmission efficiency, can transmit extremely large power, is excellent in durability, and is excellent in quietness.
Note that the power transmission device of the present invention is not limited to a mode in which the groove widths of both the drive pulley 60 and the driven pulley 70 are changed, and only one of the groove widths is changed and the other is not changed. The aspect made into width may be sufficient. In the above description, the groove width is continuously (stepless) changed. However, the groove width may be changed stepwise or may be applied to other power transmission devices such as a fixed type (no shift). .

Moreover, although the power transmission surfaces 5, 6 (end surfaces) of the first pins 3 contact the corresponding sheave surfaces 62a, 63a, 72a, 73a to transmit power, the present invention shows that the power transmission surfaces are The present invention can also be applied to a type of chain including other power transmission members such as a power transmission block having the same.
The present invention is not limited to the contents of the above-described embodiments, and various modifications can be made within the scope of the claims.

1 is a perspective view schematically showing a configuration of a main part of a power transmission chain for a chain type continuously variable transmission according to an embodiment of a power transmission chain of the present invention. It is a cross-sectional top view of the principal part of the chain shown in FIG. (A) is sectional drawing which follows the II-II line of FIG. 2, (b) is sectional drawing which follows the III-III line of FIG. (A) is a cross-sectional front view of the short link which concerns on other embodiment of this invention, (b) is a cross-sectional front view of a long link. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view schematically showing a main configuration of a chain type continuously variable transmission according to an embodiment of a power transmission device of the present invention. FIG. 6 is a partially enlarged sectional view of a drive pulley (driven pulley) and a chain of the chain type continuously variable transmission shown in FIG. 5.

Explanation of symbols

1 Chain (Power transmission chain)
3 First pin (one of a pair of pins)
4 Second pin (the other of a pair of pins)
9 Front through-hole 10 Rear through-hole 20 Connection means 21 Short link (link with relatively short connection pitch, second link)
22 long links (links with relatively long connection pitch, first link)
60 Drive pulley (first pulley)
70 Driven pulley (second pulley)
62a, 63a, 72a, 73a Sheave surface L1 (short link) total length L2 (long link) total length L7 (short link) thickness L8 (long link) thickness P1 (short link) connection pitch P2 (long) Link pitch (link) X Chain travel direction

Claims (5)

In a power transmission chain that includes a plurality of links arranged in the chain traveling direction, and the corresponding links are connected to each other using a connecting means including a pair of pins that are in rolling contact with each other.
The plurality of links include a plurality of links having different connection pitches,
A link having a relatively short connection pitch is characterized in that at least one of surface hardness, wall thickness and material strength is made larger than a link having a relatively long connection pitch.   The power transmission chain according to claim 1, wherein the link having a relatively short connection pitch has a shorter overall length in the chain traveling direction than a link having a relatively long connection pitch.   3. The Rockwell hardness HRC of the surface of the link having a relatively short connection pitch is 3 or more higher than the Rockwell hardness HRC of the surface of the link having a relatively long connection pitch. And power transmission chain. In Claim 1, 2 or 3, the plurality of links include first and second links, and each of the links has a front through hole and a rear through hole arranged in front and rear in the chain traveling direction, respectively.
The pair of pins is press-fitted and fixed in the front through hole of the first link and is movably fitted in the rear through hole of the second link, and moved to the front through hole of the first link. And a second pin fixedly fitted in a rear through hole of the second link.   A first and a second pulley each having a pair of conical sheave surfaces facing each other and wound between these pulleys to transmit power in contact with the sheave surfaces. A power transmission device comprising the power transmission chain according to claim 4.

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