JP2006226508A - Power transmission chain and power transmission device having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power transmission chain capable of improving transmission efficiency, reducing noise, and improving practical durability. <P>SOLUTION: This chain has a plurality of links 2 and a plurality of coupling members 200. The respective coupling members 200 include a first pin 3 and a second pin 4 contacting in a contact part T with this pin. In a front through-hole 9 of the respective links 2, the first pin 3 is loosely fitted, and the second pin 4 is pressed in and fixed. In a rear through-hole, the first pin is pressed in and fixed, and the second pin is loosely fitted. A moving locus of the contact part T caused by bending between the links 2 forms an involute curve INV. A contact part T1 in a straight line area of the chain is arranged in a range within 35% of the total length N2 of the second pin 4 from a central part 39 of the corresponding second pin 4 in the orthogonal direction V. <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 has a plurality of links arranged in the chain traveling direction and links adjacent to each other in the chain traveling direction. Are connected to each other by a pin and an interpiece that can roll and move (see, for example, Patent Document 1).
A pair of through holes are formed in each link of the chain of Patent Document 1. A pin is press-fitted and fixed in one through hole and an interpiece is loosely fitted, and a pin is loosely fitted in the other through-hole and the interpiece is press-fitted and fixed. As a result, when the pin contacts the pulley, the pin is hardly rotated with respect to the pulley to reduce friction loss and improve transmission efficiency.

In addition, the pin has an involute curve on the side surface in contact with the interpiece. This prevents the pin and the corresponding link from swinging in the radial direction of the pulley before and after the pin is engaged with the pulley, and suppresses the occurrence of minute vibration like string vibration in the power transmission chain. In order to reduce noise.
Japanese Patent Laid-Open No. 8-31725

  In the state where the power transmission chain is straightened, the contact position between the pin and the interpiece is set at the inner end of the interpiece with respect to the chain radial direction when the chain is bent. As a result, the tension applied to the link from the pin and the interpiece is unevenly distributed to the inner portion of the link in the chain radial direction. As a result, when the power transmission chain is driven, the amplitude value of the repetitive stress generated in the link locally increases at the inner portion, which is not preferable in terms of improving practical durability. In particular, since the pins and interpieces corresponding to the links are press-fitted, the amplitude value of the repeated stress at the press-fitted portion becomes high, which is not preferable.

  The present invention has been made under such a background. A power transmission chain that can improve transmission efficiency, reduce noise, and improve practical durability, and a power transmission device including the same. The purpose is to provide.

  In order to achieve the above object, the present invention provides a power transmission chain (1) comprising a plurality of links (2) and a plurality of connecting members (200) for connecting these links so as to bend each other. The member includes a first power transmission member (3; 3A) having a power transmission portion (17) for pulley engagement at each of the pair of end portions (16), and a second power paired with the first power transmission member. Each link includes first and second through holes (9, 10) arranged in the chain traveling direction (X), and the first through hole (9) includes: The first power transmission member is fitted in such a manner that the first power transmission member can be moved relative to the second power transmission member, and the second power transmission member is fitted into the second through hole (10) with the relative movement restricted. The member is fitted with the relative movement restricted and the second movement The transmission member is fitted so as to be relatively movable, and the first and second power transmission members that form a pair have opposed portions (12, 19; 12A, 19) that face each other, and face each other. The opposing portions roll and slide in contact with each other at a contact portion (T; TA) that is displaced with the bending between the links, and the movement locus of the contact portion with the bending between the links forms a predetermined curve (INV), The predetermined curve includes a change rate increasing region in which a change rate of a displacement amount of the contact portion on the predetermined curve increases as the bending angle (φ) between the links increases, and a linear region of the power transmission chain The contact portion (T1; T1A) of the second power transmission member from the central portion (39) of the second power transmission member with respect to the orthogonal direction (V) orthogonal to both the chain traveling direction and the chain width direction (W) Total length of power transmission member (N2) It is characterized by being arranged within a range of 35% or less.

In addition, the alphanumeric characters in parentheses represent corresponding components in the embodiments described later. The same applies hereinafter.
According to the present invention, when the first power transmission member contacts the pulley and transmits power, the first power transmission member can be prevented from rotating with respect to the pulley. High transmission efficiency can be achieved by reducing friction loss with the pulley. Further, by providing a change rate increasing region in the curve of the movement locus of the contact portion, the first power transmission member and the corresponding link are arranged in the radial direction of the pulley before and after the first power transmission member is engaged with the pulley. Oscillation can be suppressed, generation of minute vibration like string vibration in the power transmission chain can be suppressed, and noise can be reduced. Further, the position of the contact portion in the linear region of the power transmission chain is set in the vicinity of the center portion of the second power transmission member. Thereby, it can suppress that the load which acts on a link from the 1st and 2nd power transmission member acts on the orthogonal direction, and can suppress that the stress of a link becomes high locally. As a result, it is possible to improve the durability (fatigue life) of the link by suppressing the local increase in the amplitude value of the cyclic stress generated in the link when the power transmission chain is driven. As a result, the durability of the power transmission chain can be improved. Can be improved.

The contact portion in the linear region of the power transmission chain is preferably disposed within a range of 30% or less of the total length of the second power transmission member from the central portion of the second power transmission member with respect to the orthogonal direction. More preferably, it is disposed within a range of 20%.
In the present invention, the predetermined curve may include an involute curve (INV). In this case, before and after the first power transmission member engages with the pulley, the first power transmission member and the corresponding link can be more effectively suppressed from swinging in the radial direction of the pulley. Can be further reduced.

  Further, in the present invention, the contact portion in the linear region of the power transmission chain is disposed on the inner side in the chain radial direction when the chain is bent than the central portion of the second power transmission member in the orthogonal direction. There is. In this case, the maximum value of the displacement amount of the contact portion accompanying the bending between the links can be increased. As a result, the maximum value of the bending angle between the links can be further increased.

  In the present invention, the thickness (D2) of the second power transmission member in the chain traveling direction may be thinner than the thickness (D1) of the first power transmission member in the chain traveling direction. In this case, the size of the power transmission chain can be reduced by making the second power transmission member thinner. Here, by reducing the thickness of the second power transmission member, the contact area between the second power transmission member and the link decreases, and the pressure (surface pressure) acting on the link from the second power transmission member is However, since the practical durability of the link is sufficiently ensured, the thickness of the second power transmission member can be sufficiently reduced without impairing the practical durability.

  In the present invention, the first and second pulleys (60, 70) each having a pair of conical surface sheave surfaces (62a, 63a, 72a, 73a) facing each other and the pulleys are wound around these pulleys. And the power transmission chain that engages with the sheave surface and transmits power. In this case, a power transmission device having excellent transmission efficiency, quietness, and durability can be realized.

Preferred embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 schematically shows a main configuration of a chain-type continuously variable transmission (hereinafter also simply referred to as a continuously variable transmission) as a power transmission device including a power transmission chain according to an embodiment of the present invention. It is a perspective view. Referring to FIG. 1, a continuously variable transmission 100 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, and a second pulley. And a driven pulley 70 made of metal (such as structural steel) and an endless power transmission chain 1 (hereinafter also simply referred to as a chain) wound between the pulleys 60 and 70. . In addition, the chain 1 in FIG. 1 has shown a partial cross section for easy understanding.

  FIG. 2 is a partially enlarged sectional view of the drive pulley 60 (driven pulley 70) and the chain 1 of FIG. Referring to FIGS. 1 and 2, drive pulley 60 is attached to input shaft 61 connected to a vehicle drive source so as to be capable of transmitting power, and includes fixed sheave 62 and movable sheave 63. Yes. The fixed sheave 62 and the movable sheave 63 have a pair of sheave surfaces 62a and 63a that face each other. Each sheave surface 62a, 63a includes a conical inclined surface. 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 (left-right direction in FIG. 2) at the time of shifting. As a result, the groove width is changed. Thus, the effective radius R of the pulley 60 with respect to the chain 1 can be changed by moving the chain 1 in the radial direction of the input shaft 61 (vertical direction in FIG. 2).

On the other hand, as shown in FIGS. 1 and 2, the driven pulley 70 is attached to an output shaft 71 that is connected to a drive wheel (not shown) so as to be capable of transmitting power and is integrally rotatable. A fixed sheave 73 and a movable sheave 72 each having a pair of opposed sheave surfaces 73a and 72a for forming a groove for sandwiching the chain 1 with high pressure are provided.
A hydraulic actuator (not shown) is connected to the movable sheave 72 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 72 during shifting. It has become. Thereby, the effective radius R regarding the chain 1 of the pulley 70 can be changed by moving the chain 1.

FIG. 3 is a cross-sectional view of the main part of the chain 1. FIG. 4 is a cross-sectional view taken along line II-II in FIG. 3 and shows a straight region of the chain 1. FIG. 5 is a side view of the bent region of the chain 1.
In the following description, the description will be made with reference to the linear region of the chain 1 when described with reference to FIG. 4, and the description will be made with reference to the bent region of the chain 1 when described with reference to FIG.

Referring to FIGS. 3 and 4, chain 1 includes a plurality of links 2 and a plurality of connecting members 200 that connect these links 2 so as to be able to bend each other.
Each connecting member 200 includes a first pin 3 as a first power transmission member and a second pin 4 as a second power transmission member paired therewith. The first pin 3 rolls and comes into sliding contact with the second pin 4 forming a pair as the link 2 is bent.

The rolling sliding contact means a contact including at least one of a rolling contact and a sliding contact.
Hereinafter, a direction along the traveling direction of the chain 1 is referred to as a chain traveling direction X, and a direction perpendicular to the chain traveling direction X and along the longitudinal direction of the first and second pins 3 and 4 is defined as the chain width direction W. A direction perpendicular to both the chain traveling direction X and the chain width direction W is referred to as an orthogonal direction V.

Each link 2 is formed in a plate shape, and is disposed between a front end portion 5 and a rear end portion 6 as a pair of end portions arranged in the front and rear in the chain traveling direction X, and between the front end portion 5 and the rear end portion 6. An intermediate portion 7 is included.
The front end portion 5 and the rear end portion 6 are respectively formed with a front through hole 9 as a first through hole and a rear through hole 10 as a second through hole. The intermediate portion 7 has a column portion 8 that partitions the front through hole 9 and the rear through hole 10. The peripheral edge of each link 2 is formed in a smooth curve and has a shape in which stress concentration hardly occurs.

  First to third link rows 51 to 53 are formed using the link 2. Specifically, each of the first link row 51, the second link row 52, and the third link row 53 includes a plurality of links 2 arranged in the chain width direction W. In each of the first to third link rows 51 to 53, the links 2 in the same link row are aligned so that the positions in the chain traveling direction X are the same. The first to third link rows 51 to 53 are arranged side by side along the chain traveling direction X.

The links 2 of the first to third link rows 51 to 53 can be rotated relative to the links 2 of the corresponding first to third link rows 51 to 53 using the corresponding connecting members 200 (bendable). It is connected to.
Specifically, the front through-hole 9 of the link 2 of the first link row 51 and the rear through-hole 10 of the link 2 of the second link row 52 correspond to each other side by side in the chain width direction W. The links 2 of the first and second link rows 51 and 52 are connected to each other so as to be bent in the chain traveling direction X by the connecting member 200 inserted through the through holes 9 and 10.

Similarly, the front through-hole 9 of the link 2 of the second link row 52 and the rear through-hole 10 of the link 2 of the third link row 53 correspond to each other along the chain width direction W. The links 2 of the second and third link rows 52 and 53 are connected to each other so as to be bent in the chain traveling direction X by the connecting member 200 that is inserted through the through holes 9 and 10.
In FIG. 3, only one each of the first to third link rows 51 to 53 is shown, but the first to third link rows 51 to 53 are repeated along the chain traveling direction X. Has been. Then, the links 2 in the two link rows adjacent to each other in the chain traveling direction X are sequentially connected by the corresponding connecting members 200 to form an endless chain 1.

Referring to FIGS. 3 and 4, the first pin 3 is a long (plate-like) member extending in the chain width direction W. The peripheral surface 11 of the first pin 3 extends in parallel to the chain width direction W.
The peripheral surface 11 is formed as a smooth surface, and includes a front portion 12 as a facing portion facing forward in the chain traveling direction X, a rear portion 13 as a back portion facing backward in the chain traveling direction X, and an orthogonal direction V. One end 14 and the other end 15 as a pair of opposite ends.

The front part 12 is opposed to a later-described rear part 19 of the paired second pin 4 and is in rolling contact with the rear part 19 at a contact part T (contact point as viewed from the chain width direction W). .
The rear portion 13 is formed on a flat surface. This flat surface has a predetermined inclination angle B (attack angle) with respect to a predetermined plane A (in FIG. 4, a plane orthogonal to the paper surface) orthogonal to the chain traveling direction X, It is suitable.

The one end portion 14 constitutes an end portion on the chain outer peripheral side (one in the orthogonal direction V) of the peripheral surface 11 of the first pin 3 and is formed in a curved surface that is convexly curved toward the chain outer peripheral side. Yes. A substantially central portion of the one end portion 14 in the circumferential direction of the first pin 3 is a top portion 23 on the chain outer peripheral side of the first pin 3.
The other end portion 15 constitutes an end portion on the chain inner peripheral side (the other in the orthogonal direction V) of the peripheral surface 11 of the first pin 3, and has a curved surface that is convexly curved toward the inner peripheral side of the chain. Is formed. An intermediate portion of the other end portion 15 in the circumferential direction of the first pin 3 includes a top portion 24 on the inner circumferential side of the first pin 3.

In the following, in the orthogonal direction V, a side from the one end portion 14 toward the other end portion 15 is referred to as a chain inner peripheral side, and a side from the other end portion 15 toward the one end portion 14 is referred to as a chain outer peripheral side.
The pair of end portions 16 in the longitudinal direction (chain width direction W) of the first pin 3 protrudes in the chain width direction W from the links 2 arranged at the pair of end portions in the chain width direction W, respectively. Each of the pair of end portions 16 is provided with an end surface 17 as a power transmission portion for pulley engagement.

Referring to FIGS. 2 and 5, the end surface 17 is for frictional contact (engagement) with the corresponding sheave surfaces 62a, 63a, 72a, 73a of the pulleys 60, 70.
The first pin 3 is sandwiched between the corresponding sheave surfaces 62a, 63a, 72a, 73a, whereby power is transmitted between the first pin 3 and the pulleys 60, 70. Since the end surface 17 of the first pin 3 directly contributes to power transmission, the first pin 3 is formed of a high-strength wear-resistant material such as bearing steel (SUJ2), for example.

When viewed from the chain width direction W, the end surface 17 is in contact with the corresponding sheave surfaces 62a, 63a, 72a, 73a of the pulleys 60, 70, with the contact center point C coinciding with the centroid as the center. It is supposed to be. The contact center point C may be deviated from the centroid of the end surface 17.
Referring to FIGS. 3 and 4, the second pin 4 (also referred to as a strip or an interpiece) is formed of a material similar to that of the first pin 3 and extends in the chain width direction W (plate) Member).

The second pins 4 are formed shorter than the first pins 3 so that the pair of ends in the longitudinal direction do not contact the sheave surfaces of the pulleys. On the other hand, it is arrange | positioned ahead of the chain advancing direction X.
Referring to FIG. 6, which is an enlarged view of the periphery of the front through hole 9 in FIG. 4, in the linear region of the chain 1, the thickness D <b> 2 of the second pin 4 with respect to the chain traveling direction X is The pin 3 is thinner than the thickness D1 (D2 <D1).

Referring to FIG. 4 again, the peripheral surface 18 of the second pin 4 extends in the chain width direction W. The peripheral surface 18 is formed as a smooth surface, and includes a rear portion 19 as a facing portion facing backward in the chain traveling direction X, a front portion 20 facing forward in the chain traveling direction X, and a pair of orthogonal directions V. It has one end 21 and the other end 22 as end portions.
The rear portion 19 is formed on a flat surface orthogonal to the chain traveling direction X. As described above, the rear portion 19 faces the front portion 12 of the paired first pins 3.

The front portion 20 is formed on a flat surface substantially parallel to the rear portion 19.
The one end portion 21 constitutes an end portion on the chain outer peripheral side of the peripheral surface 18 of the second pin 4 and is formed in a curved surface that is convexly curved toward the chain outer peripheral side. A substantially central portion of the one end portion 21 in the circumferential direction of the second pin 4 is a top portion 25 on the outer peripheral side of the chain of the second pin 4.
The other end portion 22 constitutes an end portion on the inner circumferential side of the peripheral surface 18 of the second pin 4 and is formed in a curved surface that is convexly curved toward the inner circumferential side of the chain. A substantially central portion of the other end portion 22 in the circumferential direction of the second pin 4 is a top portion 26 on the inner peripheral side of the second pin 4.

  The chain 1 is a so-called press-fit type chain. Specifically, the first pin 3 is loosely fitted in the front through hole 9 of each link 2 so as to be relatively movable, and the second pin 4 paired with the first pin 3 is relatively The first pin 3 is press-fitted and fixed so that the relative movement is restricted in the rear through-hole 10 of each link 2. The second pin 4 paired with is loosely fitted so as to be relatively movable.

In other words, the first pin 3 is loosely fitted in the front through hole 9 of each link 2 so as to be relatively movable, and is press-fitted so that the relative movement is restricted in the rear through hole 10 of each link 2. The second pin 4 is fixed and press-fitted and fixed to the front through hole 9 of each link 2 so that the relative movement is restricted, and is loosely fitted to the rear through hole 10 of each link 2 so as to be relatively movable. Has been.
The loose fitting of the first pin 3 and the press-fitting and fixing of the second pin 4 in the front through hole 9 of the link 2 are performed as follows. That is, referring to FIG. 6, the peripheral portion 27 of the front through-hole 9 of the link 2 has a press-fit portion 28 into which the second pin 4 is press-fitted and a play portion into which the first pin 3 is loosely fitted. The fitting part 29 is included.

  The press-fit portion 28 is formed in a shape corresponding to the shape of the one end portion 21 and the other end portion 22 of the second pin 4, and receives the one end portion 21 and the other end portion 22 of the corresponding second pin 4. ing. A portion of the press-fit portion 28 receiving the one end portion 21 of the second pin 4 is loaded with a pressing force on the outer peripheral side of the chain by the second pin 4. Further, in the pressed-in portion 28, a portion receiving the other end portion 22 of the second pin 4 is loaded with a pressing force on the inner peripheral side of the chain by the second pin 4.

The to-be-fitted part 29 is formed in a shape larger than the cross-sectional shape of the first pin 3, and the corresponding first pin 3 can be freely moved relatively.
Referring to FIG. 7, which is an enlarged view around the rear through hole 10 in FIG. 4, the press-fitting and fixing of the first pin 3 and the loose fitting of the second pin 4 in the rear through hole 10 of the link 2 are as follows. Has been. That is, the peripheral portion 32 of the rear through-hole 10 of the link 2 includes a press-fit portion 33 into which the first pin 3 is press-fitted and a play-fit portion 34 into which the second pin 4 is loosely fitted. Yes.

  The press-fit portion 33 is formed in a shape corresponding to the shape of the one end portion 14 and the other end portion 15 of the first pin 3 and receives the corresponding one end portion 14 and the other end portion 15 of the first pin 3. ing. In the pressed-in portion 33, a portion receiving the one end portion 14 of the first pin 3 is subjected to a pressing force on the outer peripheral side of the chain by the first pin 3. In addition, in the pressed-in portion 33, the portion receiving the other end portion 15 of the first pin 3 is pressed by the first pin 3 on the inner circumferential side of the chain.

The to-be-fitted part 34 is formed in a shape larger than the cross-sectional shape of the second pin 4, and the corresponding second pin 4 can be freely moved relatively.
Referring to FIG. 5, with the above configuration, the rear portion 19 of the second pin 4 paired with the front portion 12 of the first pin 3 is accompanied by the bending between the links 2 adjacent to each other in the chain traveling direction X. Thus, they come into rolling contact with each other, and the contact portion T is displaced toward the outer periphery of the chain as the amount of bending (bending angle) increases.

The links 2 adjacent to each other in the chain traveling direction X in the bending region of the chain 1 are relatively bent at a predetermined bending angle φ. The bending angle φ is defined as an angle formed by the first plane E1 and the second plane E2.
The first plane E1 includes the respective contact center points C of the first pins 3a and 3b inserted into the respective through holes 9 and 10 of the link 2a in one of the bent regions, and the chain width direction W A plane parallel to.

The second plane E2 is a contact center point C of each of the first pins 3b and 3c inserted into each of the through holes 9 and 10 of the other link 2b adjacent to the link 2a and the chain traveling direction X. And a plane parallel to the chain width direction W. The range of the design bending angle φ (allowable bending angle) is set to 0 ° to 30 °, for example.
The chain 1 is a so-called involute type chain, and the movement trajectory of the contact portion T accompanying the bending between the adjacent links 2 when viewed from the chain width direction W is based on the corresponding first pin 3. The involute curve INV as a predetermined curve is formed.

Specifically, referring to FIG. 4, the cross-sectional shape of front portion 12 of first pin 3 includes a shape that matches involute curve INV.
The front portion 12 of the first pin 3 includes a curved surface portion 37 that contacts the rear portion 19 of the second pin 4 that makes a pair at the contact portion T, and an extending portion 38. An extending portion 38 is disposed on the inner circumferential side of the curved surface portion 37.

The curved surface portion 37 is composed of an involute curve that matches the involute curve INV when viewed from the chain width direction W. An end portion of the curved surface portion 37 on the inner peripheral side of the chain is a predetermined starting portion F (predetermined starting point when viewed from the chain width direction W). The position of the raised portion F coincides with the position of the contact portion T1, that is, the contact portion T of the first pin 3 in the linear region of the chain 1.
In addition, the position of the raising part F and the position of the contact part T1 do not need to correspond.

The basic circle K of the involute curve of the curved surface portion 37 viewed from the chain width direction W is a circle having a center M and a radius Rb (basic circle radius, for example, 50 mm).
The center M is positioned on the chain inner peripheral side with respect to the contact portion T1 on a plane orthogonal to the chain traveling direction X and including the contact portion T1 of the first pin 3. The basic circle K and the raised portion F intersect each other.

By making the cross-sectional shape of the curved surface portion 37 into an involute curve, the curved surface portion 37 has a radius of curvature that increases from the chain inner peripheral side toward the outer peripheral side. Thereby, as the bending angle increases, the radius of curvature of the curved surface portion 37 in the contact portion T increases, and the rate of change of the displacement amount of the contact portion T on the involute curve of the curved surface portion 37 increases.
That is, the involute curve INV has a change rate increasing region in which the change rate of the displacement amount of the contact portion T on the involute curve INV increases as the bending angle φ (see FIG. 5) between the links 2 increases. Have.

Referring to FIG. 6, the feature of the present embodiment is that the first and second pins 3 in the orthogonal direction V are optimized by optimizing the arrangement of the contact portions T1 in the linear region of the chain 1. 4, the load applied to the link 2 from the bias is suppressed, and the stress of the link 2 is prevented from being biased.
Specifically, with respect to the orthogonal direction V, the contact portion T1 in the linear region of the chain 1 extends from the center portion 39 of the corresponding second pin 4 toward the chain inner peripheral side or the chain outer peripheral side. The pin 4 is arranged in a range within 35% of the total length N2. Note that the total length N2 of the second pin 4 in the orthogonal direction V refers to the distance between the pair of top portions 25 and 26 of the peripheral surface 18 of the second pin 4.

  When the contact portion T1 is arranged so as to exceed the above range with respect to the orthogonal direction V, the peripheral portions 27 and 32 of the corresponding through holes 9 and 10 from the first and second pins 3 and 4 (in FIG. Since the distribution of the load acting on the through hole 9 is biased with respect to the orthogonal direction V, the stress generated in the link 2, particularly the stress generated in the peripheral portion 27 is locally increased at the press-fit portion 28. The range of the contact portion T1 is set as described above.

Note that the contact portion T1 in the linear region of the chain 1 is, with respect to the orthogonal direction V, from the center portion 39 of the corresponding second pin 4 toward the inner periphery side of the chain or the outer periphery side of the chain. It is preferable to be disposed within a range of 30% or less of the total length N2, and more preferably within a range of 20% or less.
In the present embodiment, the position of the contact portion T1 with respect to the orthogonal direction V is aligned with the central portion 39 of the corresponding second pin 4 with respect to the orthogonal direction V.

The total length N1 of the first pin 3 in the orthogonal direction V and the total length N2 of the second pin 4 in the orthogonal direction V are substantially equal. The total length N1 of the first pin 3 in the orthogonal direction V refers to the distance between the pair of top portions 23 and 24 of the peripheral surface 11 of the first pin 3.
The position of the second pin 4 paired with the first pin 3 is aligned in the orthogonal direction V so that either one does not protrude in the orthogonal direction V. The substantially central portion of the front portion 12 of the first pin 3 with respect to the orthogonal direction V projects toward the chain traveling direction X.

Referring to FIG. 4, in the continuously variable transmission having the above schematic configuration, adjacent links 2 of chain 1 (only one link 2 is shown in FIG. 4) are connected via corresponding connecting members 200. They are pulling each other and tension is generated in the chain 1.
For this reason, when the linear region of the chain 1 is viewed from the chain width direction W, the second pin 4 paired with the first pin 3 is along the chain traveling direction X with the contact portion T1 as an action point. It is pressed. These first and second pins 3 and 4 are respectively received by corresponding peripheral portions 27 and 32 of the link 2.

As described above, according to the present embodiment, the first pin 3 is loosely fitted in the front through hole 9 of each link 2 and the second pin 4 is press-fitted and fixed. The first pin 3 is press-fitted and fixed in the rear through-hole 10 and the second pin 4 is loosely fitted.
Thereby, when each end surface 17 of the first pin 3 contacts the corresponding sheave surfaces 62a, 63a, 72a, 73a of the pulleys 60, 70 to transmit power, the paired second pins 4 are The links 2 can be bent by rolling and sliding contact with the first pin 3. At this time, between the first and second pins 3 and 4 that make a pair, the rolling contact component is large and the sliding contact component is extremely small. As a result, each end face 17 of the first pin 3 is connected to each of the above-described end surfaces 17. It is possible to prevent rotation with respect to the corresponding sheave surfaces 62a, 63a, 72a, 73a of the pulleys 60, 70, and to reduce the friction loss between the first pin 3 and the pulleys 60, 70 and to increase the transmission efficiency. Can be achieved.

  Further, since the change rate increasing region is included in the involute curve INV as the movement trajectory of the contact portion T, the first pin 3 before and after the first pin 3 engages with the corresponding pulleys 60 and 70. And it can suppress that the corresponding link 2 rock | fluctuates to the radial direction of the pulleys 60 and 70 to which it respond | corresponds. Thereby, generation | occurrence | production of the string vibration minute vibration in the chain 1 can be suppressed, and noise can be reduced.

Further, the position of the contact portion T <b> 1 in the linear region of the chain 1 is set in the vicinity of the central portion 39 of the second pin 4. Thereby, it can suppress that the load which acts on the corresponding peripheral parts 27 and 32 of the link 2 from the 1st and 2nd pins 3 and 4 acts on the orthogonal | vertical direction V, and can suppress the stress of the link 2 locally. Can be suppressed.
As a result, it is possible to improve the durability (fatigue life) of the link 2 by suppressing the amplitude of the repeated stress generated in the link 2 from being locally increased when the chain 1 is driven. As a result, the durability of the chain 1 is improved. Can be improved.

  Further, when the movement locus of the contact portion T with respect to the first pin 3 as an involute curve INV as viewed from the chain width direction W is used as an involute curve INV, the first pin 3 is engaged with the pulleys 60 and 70 before and after. , It is possible to better suppress the first pin 3 and the corresponding link 2 from swinging in the radial direction of the pulleys 60 and 70, and as a result, noise during driving of the chain 1 can be further reduced. Can do.

Further, the thickness D2 of the second pin 4 with respect to the chain traveling direction X is made thinner than the thickness D1 of the first pin 3 with respect to the chain traveling direction X. Can be reduced in size.
Here, by reducing the thickness D2 of the second pin 4, the contact area between the second pin 4 and the corresponding peripheral edge portions 27 and 32 of the link 2 is reduced, and the second pin 4 is changed to the link 2. The acting pressure (surface pressure), in particular, the pressure acting on the press-fit portion 28 of the front through-hole 9 of the link 2 is increased, but the practical durability of the link 2 is sufficiently secured, so that the practical durability is achieved. The thickness D2 of the second pin 4 can be sufficiently reduced without impairing the properties.

In this way, it is possible to realize a continuously variable transmission 100 that is excellent in transmission efficiency, quietness, and durability and that is compact.
In the present embodiment, the movement locus of the contact portion T with respect to the first pin 3 may be formed on a curve other than the involute curve INV. For example, the cross-sectional shape of the curved surface portion 37 may be formed as a curve other than a curve that matches the involute curve INV. Examples of such a curve include the following curves. That is, it is possible to exemplify a curve having a plurality of curvature radii and including a region in which the curvature radius increases from the chain inner peripheral side toward the outer peripheral side.

The thickness D2 of the second pin 4 may be the same as the thickness D1 of the first pin 3 (D1 = D2), or may be thicker than the thickness D1 (D2> D1).
FIG. 8 is a cross-sectional view of a main part of another embodiment of the present invention. Below, a different point from embodiment shown in FIGS. 1-7 is demonstrated, the same code | symbol is attached | subjected to a figure about the same structure, and the description is abbreviate | omitted.

Referring to FIG. 8, this embodiment is mainly different from the above embodiment in that the contact portion T1A in the linear region of the chain is offset in the orthogonal direction V with respect to the center portion 39 of the second pin 4. It is in the point arranged.
Specifically, the contact portion T1A is disposed on the inner side (chain inner peripheral side) in the chain radial direction when the chain is bent than the central portion 39. The contact portion T <b> 1 </ b> A is arranged at a position separated from the central portion 39 of the second pin 4 by, for example, 10% of the entire length N <b> 2 of the second pin 4 in the orthogonal direction V. With respect to the orthogonal direction V, the contact portion T1A and the central portion 39 are separated by a distance P.

In this case, when viewed from the chain width direction W, the length of the curved surface portion 37A on the peripheral surface 11A of the first pin 3A can be secured longer. Thereby, the maximum value of the displacement amount of the contact part TA accompanying the bending between the links 2 can be increased. As a result, the maximum value of the bending angle between the links 2 can be further increased.
The contact portion T1A may be disposed on the outer side in the chain radial direction when the chain is bent (on the outer side of the chain) than the central portion 39.

The present invention is not limited to the above embodiments.
For example, in each of the above embodiments, the shape of the rear portion 19 of the second pin 4 that makes a pair with the shape of the front portions 12 and 12A of the first pins 3 and 3A may be interchanged. Further, the second pin 4 may be engaged with the pulleys 60 and 70.
Further, a member having a power transmission unit similar to the end surface of the first pin is arranged in the vicinity of each of the pair of end portions of the first pin, and the first pin and the member having the power transmission surface are arranged. A power transmission block may be provided, which may be used as the first power transmission member.

Further, the arrangement of the front through hole 9 and the rear through hole 10 of the link 2 may be interchanged. Further, a communication groove (slit) may be provided in the column portion 8 between the front through hole 9 and the rear through hole 10 of the link 2. In this case, the elastic deformation amount (flexibility) of the link 2 can be increased, and the stress generated in the link 2 can be further reduced.
Further, 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 may be a mode in which only one of the groove widths is changed and the other is a fixed width that does not change. good. Furthermore, although the aspect in which the groove width continuously changes (steplessly) has been described above, the groove width may be changed stepwise or may be applied to other power transmission devices such as a fixed type (stepless). .

Examples 1, 2, and 3 and Comparative Examples 1 and 2 relating to the above power transmission chain were produced.
In the first embodiment, the position of the contact portion between the first and second pins in the linear region of the chain is aligned with the center portion of the second pin in the orthogonal direction.
In the second embodiment, the position of the contact portion between the first and second pins in the linear region of the chain is 20% of the total length of the second pin from the center of the second pin with respect to the orthogonal direction. Offset to the inner circumference of the chain.

In the third embodiment, the position of the contact portion between the first and second pins in the linear region of the chain is 30% of the total length of the second pin from the center of the second pin with respect to the orthogonal direction. Offset to the inner circumference of the chain.
In Comparative Example 1, the position of the contact portion between the first and second pins in the linear region of the chain is 37.5 of the total length of the second pin from the center of the second pin with respect to the orthogonal direction. % Is offset to the inner circumference side of the chain.

In Comparative Example 2, the position of the contact portion between the first and second pins in the linear region of the chain is 40% of the total length of the second pin from the center portion of the second pin with respect to the orthogonal direction. Offset to the inner circumference of the chain.
A fatigue test was conducted using Examples 1 to 3 and Comparative Examples 1 and 2. Specifically, each of Examples 1 to 3 and Comparative Examples 1 and 2 is subjected to a test in which tension is repeatedly applied horizontally to a link in a linear region, and the number of times until the link breaks (number of repetitions) is measured. did. Then, the ratio (life ratio) between the number of repetitions for Example 1 and the number of repetitions for Examples 1, 2, 3 and Comparative Examples 1, 2 was determined. The results are shown in FIG.

As shown in FIG. 9, among Examples 1 to 3 and Comparative Examples 1 and 2, the life ratio relating to Example 1 is the highest, and the fatigue life relating to Example 1 is the highest. Also in Examples 2 and 3, the life ratio exceeds 0.7, and a fatigue life exceeding 70% of the fatigue life related to Example 1 is achieved.
On the other hand, the life ratios of Comparative Examples 1 and 2 are each less than 0.5, and the fatigue life is less than 50% of the fatigue life of Example 1.

  Thus, it was demonstrated that Examples 1 to 3 were excellent in terms of fatigue life.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view schematically showing a main configuration of a chain type continuously variable transmission as a power transmission device including a power transmission chain according to an embodiment of the present invention. It is a partial expanded sectional view of the drive pulley (driven pulley) and chain of FIG. It is sectional drawing of the principal part of a chain. It is sectional drawing which follows the II-II line | wire of FIG. 3, and has shown the linear area | region of the chain. It is a side view of the bending area | region of a chain. It is an enlarged view of the front through-hole periphery of FIG. FIG. 5 is an enlarged view of the vicinity of a rear through hole in FIG. 4. It is sectional drawing of the principal part of another embodiment of this invention. It is a graph shown about the result of a fatigue test.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Chain (power transmission chain), 2 ... Link, 3, 3A ... 1st pin (1st power transmission member), 4 ... 2nd pin (2nd power transmission member), 9 ... Front through-hole (First through hole), 10 ... rear through hole (second through hole), 12, 12A ... front part (opposing part), 16 ... end part, 17 ... end face (power transmission part), 19 ... rear part ( Opposing part), 39 ... central part, 60 ... drive pulley (first pulley), 70 ... driven pulley (second pulley), 62a, 63a, 72a, 73a ... sheave surface, 100 ... continuously variable transmission (power) (Transmission device), 200 ... connecting member, D1, D2 ... thickness, INV ... involute curve (predetermined curve), N2 ... full length, T, T1, TA, TA1 ... contact part, V ... orthogonal direction, W ... chain width direction , X ... Chain traveling direction, φ ... Bending angle

Claims (5)

In a power transmission chain comprising a plurality of links and a plurality of connecting members that connect these links so as to be bendable,
Each of the connecting members includes a first power transmission member having a power transmission portion for pulley engagement at each of a pair of ends, and a second power transmission member paired with the first power transmission member,
Each link includes first and second through holes arranged in the chain traveling direction,
The first power transmission member is fitted into the first through hole so as to be relatively movable, and the second power transmission member is fitted with the relative movement being restricted,
In the second through hole, the first power transmission member is fitted so that the relative movement is restricted, and the second power transmission member is fitted so as to be relatively movable,
The first and second power transmission members that form a pair have opposing portions that face each other,
The opposing portions facing each other are in rolling contact with each other at a contact portion that is displaced along with the bending between the links,
The movement trajectory of the contact portion accompanying the bending between the links forms a predetermined curve,
The predetermined curve includes a change rate increasing region in which a change rate of a displacement amount of the contact portion on the predetermined curve increases in accordance with an increase in a bending angle between links.
The contact portion in the linear region of the power transmission chain is 35% of the total length of the second power transmission member from the center of the second power transmission member in the orthogonal direction perpendicular to both the chain traveling direction and the chain width direction. A power transmission chain characterized by being arranged within a range.   2. The power transmission chain according to claim 1, wherein the predetermined curve includes an involute curve.   In Claim 1 or 2, the contact part in the linear area | region of the said power transmission chain is arrange | positioned rather than the center part of the said 2nd power transmission member regarding the said orthogonal direction inside the chain radial direction at the time of chain bending. A power transmission chain characterized by that.   4. The power transmission chain according to claim 1, wherein the thickness of the second power transmission member in the chain traveling direction is made thinner than the thickness of the first power transmission member in the chain traveling direction. .   A first pulley and a second pulley each having a pair of conical sheave surfaces facing each other, and wound around these pulleys and engaged with the sheave surfaces to transmit power. A power transmission device comprising the power transmission chain according to claim 4.

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