CN112178131B

CN112178131B - Chain

Info

Publication number: CN112178131B
Application number: CN202010618759.1A
Authority: CN
Inventors: 大畠俊和; 石王章文
Original assignee: Daido Kogyo Co Ltd
Current assignee: Daido Kogyo Co Ltd
Priority date: 2019-07-05
Filing date: 2020-07-01
Publication date: 2022-04-26
Anticipated expiration: 2040-07-01
Also published as: JP2021011919A; KR102313760B1; JP7406318B2; CN112178131A; KR20210005518A

Abstract

The invention provides a chain which can reduce the chain pitch without damaging the strength of the chain and improve the silencing of the chain for a stepless speed change device. The cross-sectional shape of the pin (23) is formed by a semicircle having a rolling surface (23 b). The first link (19) and the second link (20) are configured such that a pin (23) is fitted into one pin hole (25) of an outer plate (21) and an inner plate (22) so as to rotate integrally. The rolling surface (23b) of the pin (23) is fitted and inserted in a rolling manner in the rolling region F of the pin holes (26, 29) on the other side of the outer and inner plates (21, 22).

Description

Chain

Technical Field

The present invention relates to a chain in which a first link and a second link formed of link plates are alternately connected by a pin, and more particularly, to a chain suitable for a belt type Continuously Variable Transmission (CVT).

Background

Generally, as shown in fig. 11, a chain 1 is used as a CVT chain by alternately connecting first and

second links

5 and 6, each of which is formed of a link plate 3 having

circular pin holes

2 and 2 at both ends thereof, by a pin to form an endless loop, and bringing both ends of the pin into contact with pulleys of a V-pulley. Since the

link plates

3, 3 in the same row of the first and

second links

5, 6 are arranged with a predetermined gap therebetween, the dangerous cross-sectional length A of the link plate is equal to or less than half of the distance obtained by subtracting the pin hole diameter D from the chain pitch P [ A < (P-D)/2 ].

In a CVT chain, there is proposed a chain in which a pin (cradle member) is formed to have a laterally asymmetrical cross-sectional shape, a rolling surface of the pin is in rolling contact with a rolling area of a pin hole of a link plate (link element), and a contact portion of the pin with a pulley is offset from a center of the pin (patent document 1). The chain has link plates in which rolling areas of left and right pin holes are different between an inner surface and an outer surface, and the left and right asymmetric pins are fitted and inserted into the left and right pin holes of the link plates, respectively, so that a rolling interval between two adjacent pins and an interval between contact points of the pins with a pulley are randomized into three lengths (average, long, short), thereby dispersing a frequency of noise caused by contact between the pins and the pulley and realizing low noise.

Patent document 1: japanese Kokai publication No. 2009-520161

In the chain 1 having the link plates having the pin holes formed in the circular shape, the dangerous cross-sectional length a is a value corresponding to the chain transmission capability, and therefore the pitch P of the chain 1 is defined to be equal to or greater than a predetermined value.

Even if the chain of patent document 1 has a link in which the distance between the pin and the rolling surface and the rolling region of the pin hole is short, the pin hole having the rolling region is required at both ends of the link plate, and the length of the link plate is defined to a predetermined value, and the function of reducing the chain pitch cannot be achieved.

Disclosure of Invention

Therefore, an object of the present invention is to provide a chain that can reduce the chain pitch without impairing the strength of the chain, thereby improving the quietness of the chain.

The chain (13) of the present invention is a chain in which a first link (19) and a second link (20) each having an outer plate (21) and an inner plate (22) are alternately and annularly connected by passing a pin (23) through a pair of pin holes (25, 26) formed in the outer plate (21) and the inner plate (22), the chain (13) being characterized in that,

the cross-sectional shape of the pin (23) is formed by an asymmetrical shape having a rolling surface (23b),

the first link (19) and the second link (20) have the outer plates (21) disposed at both ends in the width direction, and have a plurality of inner plates (22) disposed between the outer plates (21),

the pin (23) is fixed to one pin hole (25) of the outer plate (21) of the first link (19) and the second link (20), and the pin (23) is fitted and inserted into one pin hole (27) of the inner plate (22) so as to rotate integrally,

the rolling surface (23b) of the pin (23) is fitted into the pin holes (26, 29) of the outer plate (21) and the inner plate (22) of the first link (19) and the second link (20) so as to be rollable.

For example, referring to fig. 1 and 5, both end surfaces of the pin (23) are constituted by inclined surfaces (23c) that come into contact with pulleys (14, 15) (16, 17) of V pulleys (11, 12) of a Continuously Variable Transmission (CVT) (10).

For example, referring to FIGS. 3, 4 and 6, the outer plates (21) of the first link (19) and the second link (20) have the same shape,

the inner plates (22) of the first link (19) and the second link (20) are formed in the same shape,

the pin holes (26, 29) on the other of the outer plate (21) and the inner plate (22) are formed in a semicircular shape, one side (E) is formed in an arc surface, and the other side (F) is formed in a rolling area in which the pin rolls on the rolling surface (23b) of the pin (23).

For example, referring to FIG. 5, the pin (23) has a semicircular cross-sectional shape, one side (23a) is an arc surface having a predetermined radius (R1), the other side (23b) as the rolling surface is an arc surface having a radius (R2) larger than the predetermined radius (R1),

the other side (F) of the pin holes (26, 29) of the outer plate (21) and the inner plate (22) which is the rolling area is a linear shape.

For example, referring to FIGS. 7, 8 and 9, the other side (F) of the pin holes (26, 29) of the outer plate (21) and the inner plate (22) which is the rolling area is inclined so as to expand in the outer diameter direction of the chain,

the other side (F) of the pin holes (26, 29) which is a rolling area is configured such that the outer diameter side (beta) (L3) is wider than the inner diameter side (alpha) (L2) of the chain with respect to a contact position (d) with a rolling surface of the pin in a straight state of the chain.

For example, referring to fig. 9, the dangerous cross-sectional length of the outer plate (21) and the inner plate (22) on the pin hole (26) and (29) side is configured to be longer on the inner diameter side (L4) than on the outer diameter side (L5) of the chain.

For example, referring to fig. 3 and 4, the pin (23) is press-fitted into and fixed to one pin hole (25) of the outer plate (21) of the first link (19) and the second link (20).

In addition, the reference numerals in parentheses are used for comparison with the drawings, and do not affect the description of the claims at all.

According to the invention of claim 1, since the outer plates and the inner plates of the first link and the second link are respectively fitted and inserted with pins so as to be fixed to or integrally rotate with one pin hole, and the rolling surfaces of the pins roll with the other pin hole to bend the chain, the tensile stress of the power transmission chain can be stably and reliably transmitted, and each link rolls with respect to one pin, and the chain can be stably bent by highly accurate rolling, and accurate chain transmission can be performed.

Since the pins are formed in an asymmetric shape having a rolling surface, and one pin rolls and the other pin is connected to each link so as to be fixed or integrally rotated, the lengths of the outer plates and the inner plates can be shortened, the chain pitch can be reduced without impairing the strength of the chain, and the chain quietness can be improved.

According to the invention of claim 2, the present chain is applied to a Continuously Variable Transmission (CVT), and contributes to silencing of the continuously variable transmission while maintaining transmission capacity.

According to the invention of claim 3, the outer plate and the inner plate may have the same shape in the first link and the second link, and the pin holes of the other of the outer plate and the inner plate may be formed in a semicircular shape, so that the chain pitch can be shortened, and the noise reduction of the chain can be achieved with a relatively simple structure.

According to the invention of claim 4, the pin is formed in a semicircular shape by the arcuate surfaces having different radii, and the pin can be accurately and stably rolled in the rolling area between the rolling surface formed by the arcuate surface having a large radius and the pin hole formed in a straight shape with a relatively simple configuration.

According to the invention of claim 5, since the rolling region of the other pin hole is inclined so as to expand in the outer diameter direction of the chain and the outer diameter side of the chain is wider than the inner side with respect to the contact position with the rolling surface of the pin in the chain straight state, the chain can be bent at a necessary bending angle with respect to the chain winding (inner diameter) direction while keeping the tensile strength of the chain while suppressing the entire bending surface within a predetermined range, and can function as a chain, particularly as a chain for a Continuously Variable Transmission (CVT).

According to the invention of claim 6, since the dangerous cross-sectional length of the other pin side is set to be longer on the inner diameter side than on the outer diameter side of the chain, the difference in stress at the plate end portion caused by the rolling region in which the pin holes are formed obliquely is absorbed by the difference in the dangerous cross-sectional length in the straight state of the chain in which the chain tensile force acts most, and the tensile strength of the outer plate and the inner plate can be secured.

According to the invention of claim 7, since the pins are press-fitted and fixed to the pin holes of one of the outer plates of the first link and the second link, the rows of the plates of the chain can be maintained in order with a relatively simple structure.

Drawings

Fig. 1 is a schematic perspective view showing a Continuously Variable Transmission (CVT) using a chain according to the present invention.

Fig. 2 is a perspective view showing a chain according to an embodiment of the present invention.

Fig. 3 is an exploded perspective view showing a first link of the chain.

Fig. 4 is an exploded perspective view showing a second link of the chain.

Fig. 5 shows the pins of the chain, with (a) a front view and (b) a side view.

Fig. 6 (a) is a side view showing the outer plate of the chain, and fig. 6 (b) is a side view showing the inner plate.

Fig. 7 (a) is a side sectional view of the chain in a linear state, and fig. 7 (b) is a side sectional view showing a pin and a pin hole portion.

Fig. 8 (a) is a side cross-sectional view showing a bent state of the chain, and fig. 8 (b) is a side cross-sectional view showing a pin and a pin hole portion in this state.

Fig. 9 is a side cross-sectional view showing an end portion of a link plate of the chain.

Fig. 10 is a side view comparing a chain according to the invention with a chain based on the prior art.

Fig. 11 is a perspective view showing a chain according to the conventional technique.

Description of the reference numerals

10 … Continuously Variable Transmission (CVT); 11. 12 … a pulley; 13 chain(s); 14. 15, 16, 17 … pulleys; 19 … first (outer) link; 20 … second (inner) link; 21 … outer plate; 22 … inner panel; 23 … pin; 23a … side (R1 arc surface); 23b … on the other side (rolling surface); 23c … inclined plane; 25. 27 … pin hole; 26. 29 … and the other pin hole; e … side (circular arc surface); the other side of F … (scroll area); d … contact position.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in fig. 1, a Continuously Variable Transmission (CVT)10 includes a driving pulley 11, a driven pulley 12, and a chain 13. The driving pulley 11 is composed of a movable sheave 14 and a fixed sheave 15 which are formed in a conical shape and face each other, the driven pulley 12 is also composed of a movable sheave 16 and a fixed sheave 17, and a chain 13 is wound between the two

pulleys

11, 12. The chain winding radius of the driving pulley 11 is adjusted by moving the movable sheave 14 of the driving pulley 11, and the chain winding radius of the driven pulley 12 is moved in accordance with the adjustment, so that the rotation of the driving pulley 11 is transmitted to the driven pulley 12 with a stepless speed change.

As shown in fig. 2, the chain 13 is formed in an annular shape by alternately connecting first links (outer links) 19 and second links (inner links) 20 with pins 23. As shown in fig. 3, the first link 19 includes an outer plate 21 and an inner plate 22, and is connected by a pin 23. The outer plates 21 are located at both ends of the pin in the axial direction (chain width direction), and a plurality of inner plates 22 are disposed between the two outer plates 21. The outer plate 21 has a pair of

semicircular pin holes

25, 26, and the inner plate 22 has circular pin holes 27 and semicircular pin holes 29 on the left and right. The pin 23 is press-fitted into and fixed to one pin hole 25 of the outer plate, and extends through a circular pin hole 27 of the inner plate 22. The semicircular shape in the present embodiment includes not only a geometrically strict semicircular shape but also a substantially semicircular shape. In addition, the circular shape includes not only a geometrically strict circle but also a substantially circular shape.

As shown in fig. 4, the second link 20 includes an outer plate 21, an inner plate 22, and a pin 23, similarly to the outer link 19, the outer plate 21 is positioned at both ends of the pin 23 in the axial direction (chain width direction), the pin 23 is press-fitted and fixed to one pin hole 25 of the outer plate 21, and the inner plate 22 is disposed between the two outer plates 21 so that the pin 23 penetrates through a circular pin hole 27. Since the number of inner plates 22 of the second link (inner link) 20 is one less than that of the inner plates 22 of the outer link 19, the outer plates 21 of the first link (outer link) 19 are disposed at the widthwise outermost ends of the chain 13.

The first link 19 is configured such that one pin 23 is press-fitted into and fixed to one (front) pin hole 25 of the outer plate 21, the pin 23 is inserted into the pin holes 27 of the plurality of inner plates 22 so as to be movable in the axial direction, the arc surface of the pin 23 is in close contact with the outer surface of the one pin hole 27 of the inner plate 22 to transmit a tensile force, and the pin 23 is integrally connected in the rotational direction. In the second link 20, as in the outer link 19 described above, one pin 23 is press-fitted into and fixed to one pin hole 25 of the outer plate 21, and the pin 23 and one pin hole 27 of the inner plate 22 are integrally connected in the rotational direction to carry transmission tensile force and are fitted in the pin hole 27 so as to be movable in the axial direction.

The pin holes 25 on one side (front side) of the first link 19 are positioned outside the pin holes 26 on the other side (rear side) of the outer plate 21 of the second link 20 so as to overlap each other in the width direction, the inner plates 22 of the second link 20 and the inner plates 22 of the first link 19 are alternately arranged, and the first link 19 and the second link 20 are connected by the pins 23 with a pitch offset. The pin 23 integral in the rotational direction with the pin hole 25 on one side (front) of the outer plate 21 of the first link 19 and the pin hole 27 on one side (front) of the inner plate 22 is fitted to the pin hole 26 on the other side (rear) of the outer plate 21 of the second link 20 and the pin hole 29 on the other side (rear) of the inner plate 22 so as to be able to roll by a predetermined amount, and similarly, the pin 23 integral in the rotational direction with the pin hole 25 on one side (front) of the outer plate 21 of the second link 20 and the pin hole 27 on one side (front) of the inner plate 22 is fitted to the pin hole 26 on the other side (rear) of the outer plate 21 of the first link 19 and the pin hole 29 on the other side (rear) of the inner plate 22 so as to be able to roll by a predetermined amount. Thus, the first link 19 and the second link 20 can be bent by a predetermined amount by rolling of the pin holes 26 and 29 and the pin 23 on the other side (rear side), respectively.

As shown in fig. 5 (a), the pin 23 has a predetermined length L, and both left and right ends are formed by inclined surfaces 23c inclined by a predetermined angle θ so as to come into contact with the

pulleys

14, 15, 16, 17 of the Continuously Variable Transmission (CVT) 10. As shown in fig. 5 (b), the pin 23 has a laterally asymmetrical cross-sectional shape, and one surface (side) 23a is formed by an arc surface having the same radius R1 as that of the conventional round pin, and the other surface (side) 23b is formed by an arc surface having a larger radius R2 and in rolling contact with the rolling area of the pin holes 26 and 29. The one surface 23a is formed of an arc surface that can be brought into close contact with the end side arc surface G (see fig. 6 b) of one pin hole 27 of the inner panel 22, but since the pin 23 is integral with the inner panel 22 (and the outer panel 21 to be press-fitted) in the rotational direction, it may be formed of other shapes such as a compound R shape that meets the strength requirement, a gradual R shape that is formed of a continuously changing radius, a shape in which an R shape and a straight line are mixed, and a quadratic curve shape such as an ellipse. The other surface 23b of the pin 23 constitutes a rolling surface that rolls on the rolling area of the pin holes 26 and 27, and is not limited to a circular arc surface having a single radius R2, and may be other shapes such as a compound R shape, a tapered R shape, a shape in which an R shape and a straight line are mixed, and a quadratic curve shape.

As shown in fig. 6 (a), the outer plates 21 of the first link 19 and the second link 20 have pin holes 25 on one side (front side) and pin holes 26 on the other side (rear side). One pin hole 25 is formed in a similar shape that is slightly smaller than the cross-sectional shape of the pin 23, and into which the pin 23 is press-fitted and fixed. The one pin hole 25 has the same shape as the cross section of the pin for press-fitting and fixing the pin 23, but the pin 23 may be fixed by other methods such as welding, other than press-fitting, and in this case, the one pin hole 25 may have other shapes. The other pin hole 26 is formed in a shape capable of rolling with the pin 23, and the other pin hole 29 of the inner plate 22 is also formed in the same shape. The inner side surfaces (one side) E of the other pin holes 26 and 29 may have any shape as long as they do not interfere with the rolling movement of the pin 23, and are preferably circular arc surfaces having a radius R3 slightly larger than the radius R1 of the one surface 23a of the pin 23. The inner surface E may have any shape, or may have a shape continuous with one of the pin holes 25, 27.

The outer side surfaces (the other sides) F of the other pin holes 26 and 29 form rolling areas that roll on the rolling surfaces (the other surfaces) 23b of the pins 23, and the chain 13 has a large curvature in the inner diameter direction, and specifically, as described later, is formed in a linear shape that is inclined so as to extend downward (toward the chain outer diameter side) and that is perpendicular to the longitudinal center line X-X. The outer side surface (rolling region) F may be in a shape that rolls on the rolling surface (other surface) 23b of the pin 23, and the rolling surface 23b of the pin is formed of an arc surface having a radius R2, so that the outer side surface F is formed in a linear shape.

The pin hole 27 on one (front) side of the inner panel 22 is in a circular (loop) shape with good productivity, but the outer side surface G of the pin hole 27 is a portion that is matched with the one surface 23a of the pin 23 and carries and transmits a tensile force (load), and is preferably an arc surface having a radius equal to the radius R1 of the one surface 23a of the pin. The inner surface H of the pin hole 27 may have any shape, such as an arc surface having a radius slightly larger than the radius R2 of the other surface 23b of the pin 23, a straight line, or any other shape, as long as it has a margin allowing the inner panel 22 to slide in the axial direction with respect to the pin 23, and it does not contact (transmit a load to) the pin 23.

Fig. 7 is a view showing the chain 13 in a straight state, and the first link 19 and the second link 20 are coupled by a pin 23. The first link 19 (the outer plate 21, the inner plate 22, and the pin 23) is hatched, and the pin 23 is non-rotatably coupled to one (front) pin hole 25(27) of the outer plate 21 (and the inner plate 22). The pin 23 is rollably fitted into a pin hole 26(29) of the other (rear) side of the outer plate 21 (and the inner plate 22) of the second link 20. As shown in fig. 7 (b), the other pin hole 26(29) is formed by a rolling region (outer surface) F formed by a straight line inclined downward with respect to the direction in which the vertical direction (plate width direction) Y expands, and the rolling surface (other surface) 23b of the pin 23 is formed by an arc surface having a large radius R2. In the chain straight state, the rolling area (outer surface) F contacts the pin rolling surface 23b at an upper (chain inner diameter) position d. In the rolling region F, a predetermined angle α is provided above (on the chain inner diameter side) the contact position d, a predetermined angle β is provided below (on the chain outer diameter side) the contact position d, and the total (α + β) of the predetermined angles is a bending angle γ of the chain 13. The angle β on the lower side (outer diameter side) is a bending angle when the chain 13 is bent in the wrapping inner diameter direction, and the angle α on the upper side (inner diameter side) is a bending angle of the chain in the wrapping outer diameter direction. The distance between the vertical line Y at the contact position d and the vertical line Y of the rear end surface of one (front) pin 23 is a chain pitch P (see fig. 6).

Fig. 8 shows a state in which the chain 13 is bent toward the inner diameter side in the winding direction. The outer and

inner plates

21 and 22 of the first link 19 are bent upward (counterclockwise) together with the pin 23, the pin 23 moves the contact point downward while rolling the rolling surface 23b thereof in the rolling region F of the pin holes 26 and 29, and the first link 19 is bent upward with respect to the second link 20. At this time, as shown in fig. 8 (b), the arcuate surface R1 of the one surface 23a of the pin 23 and the inner surface E of the

pin hole

26, 29, which is formed of the arcuate surface R3, are movable relative to each other.

In order to bend the chain 13 largely in the inner diameter direction (winding direction), the lower (outer diameter side) angle β of the rolling region (outer surface) F of the pin holes 26, 29 of the other side (rear side) is larger than the upper (inner diameter side) angle α. The total of the angles (α + β) is the bending angle γ of the chain. When the curved surface γ of the chain becomes large, the radius R2 of the rolling surface 23b of the pin 23 becomes small, the contact surface pressure between the rolling surface of the pin and the rolling area of the pin hole increases, and the chain strength decreases, so the radius R2 of the rolling surface 23b of the pin is preferably large. Since the chain 13 is wound around the driving pulley and the driven pulley, the bending angle in the winding direction is made larger than the bending angle in the opposite direction, and the entire bending angle γ is made as small as possible while maintaining the necessary bending angle in the chain use state, so that the lower (outer diameter side) angle β and the upper (inner diameter side) angle α are made to be in appropriate proportions. Accordingly, the bending angles β and α are appropriately set so that the overall bending angle γ is minimized and the radius R2 of the pin rolling surface 23b is increased as much as possible.

In the above embodiment, the rolling area F of the pin holes 26 and 29 of the plate is formed at an angle with respect to the width direction line Y, but the rolling surface 23b of the pin 23 may be formed at an angle. In the above embodiment, the rolling areas of the pin holes 26 and 29 of the plates are formed in a linear shape, but the portion d in contact with the pins in a chain linear state may be formed in other shapes such as a linear shape or a shape in which the radius R varies as the chain bends.

Fig. 9 shows the structure of the pin holes 26 and 29 on the other (rear) side of the outer and

inner plates

21 and 22. As described above, the rolling region F, which is the outer side surface (the other side) of the other pin holes 26 and 29, is inclined with respect to the width direction line Y. In the case where the chain 13 is in a straight state, the tensile force is most effective. When the tensile force acts on the contact position d in a straight line, the lengths L2, L3 of the rolling region (outer surface) F from the contact position d are different because the outer angle α and the inner angle β are different (α < β) as described above. That is, the length L2 on the inner diameter side is smaller than the length L3 on the outer diameter side (L2< L3), and therefore a difference occurs in the stress at the plate end portions. Therefore, in the present embodiment, the dangerous cross-sectional length of the plate end is set so that the inner diameter side length L4 is greater than the outer diameter side length L5 (L4> L5), and the tensile strength on the inner diameter side (L4) is made greater than the tensile strength on the outer diameter side (L5) so as to cancel the difference in the stress, thereby maintaining the tensile strength of the outer panel 21 and the inner panel 22.

As shown in fig. 10, the pin holes 26, 29 of the other (rear) of the outer and

inner plates

21, 22 of the chain 13 of the present embodiment are formed in a semicircular shape, and therefore, the length corresponding to the dangerous cross-sectional length a is shortened as compared with the plate 3 of the conventional chain 1 shown in fig. 11. This can shorten the chain pitch while maintaining a predetermined tensile force, thereby making the chain silent.

The above embodiment has been described as a chain for a Continuously Variable Transmission (CVT), but the present invention is not limited to this, and the chain can be applied to other devices. The cross-sectional shape of the pin and the pin hole shapes of the outer plate and the inner plate are not limited to those described in the embodiment, and may be other shapes, and particularly, the pin hole 27 of one of the inner plates 22 may be a shape other than a circle, and for example, the inner surface H may be any shape. Further, the pin for fixing the outer plate and the inner plate or the pin rotating integrally with the pin is a forward pin hole, and the other pin hole having the rolling region is a rearward pin hole.

Claims

1. A chain in which a first link and a second link each having an outer plate and an inner plate are alternately and annularly connected by passing a pin through a pair of pin holes formed in the outer plate and the inner plate,

the cross-sectional shape of the pin consists of an asymmetrical shape with rolling surfaces,

the first link and the second link dispose the outer plates at both ends in the width direction and dispose a plurality of the inner plates between the outer plates,

the pin is fixed to one pin hole of the outer plate of the first link and the second link, and the pin is fitted and inserted into one pin hole of the inner plate so as to rotate integrally,

the rolling surface of the pin is inserted into the pin hole of the other of the outer plate and the inner plate of the first link and the second link so as to be rollably fitted,

the pin has a rolling surface located on the other side, which is the side where the other pin hole is located, in a state fitted and inserted in the other pin hole of the outer plate and the inner plate of the first link and the second link,

the other surface of the pin hole of the other of the outer plate and the inner plate, which is opposed to the rolling surface of the pin, serves as a rolling area in which the rolling surface of the pin rolls.

2. The chain of claim 1,

both end surfaces of the pin are formed by inclined surfaces that abut against pulleys of a V pulley of a continuously variable transmission.

3. The chain according to claim 1 or 2,

the outer plates of the first and second links are formed of the same shape,

the inner plates of the first and second links are formed of the same shape,

the pin hole of the other of the outer plate and the inner plate is formed in a semicircular shape, one side thereof is formed in an arc surface, and the other side thereof is formed in a rolling area in which the pin rolls on the rolling surface.

4. The chain of claim 3,

the pin has a semicircular cross-sectional shape, one side of the pin is an arc surface having a predetermined radius, the other side of the pin, which is the rolling surface, is an arc surface having a radius larger than the predetermined radius,

the other side of the pin hole of the other of the outer plate and the inner plate, which is the rolling region, is a linear shape.

5. The chain of claim 3,

the other side of the pin hole of the other of the outer plate and the inner plate as a rolling region is inclined so as to spread in the outer diameter direction of the chain,

the other side of the pin hole, which is a rolling area, is configured to be wider on the outer diameter side than on the inner diameter side of the chain with respect to a contact position with a rolling surface of the pin in a linear state of the chain.

6. The chain of claim 5,

the dangerous cross-sectional length of the other pin hole side of the outer plate and the inner plate is configured to be longer on the inner diameter side than on the outer diameter side of the chain.

7. The chain of claim 1,

the pin is press-fitted into and fixed to one pin hole of the outer plate of the first link and the second link.