JP2006002822A - Power transmitting chain and transmission equipped with it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power transmitting chain and a transmission equipped with it structured so that links adjoining in the chain traveling direction are coupled together by a pair of pins, capable of prolonging the lifetime in practical application and enhancing the transmitting efficiency. <P>SOLUTION: To links 2 adjoining in the chain traveling direction X are coupled together by a first 3 and a second mating pin 4 in such a way as capable of being bent. The contacting surface 12 of the first pin 3 contacts with the mating contacting surface 14 of the second pin 4. The arithmetic mean surface roughness Ra of the contacting surface 12 of the first pin 3 and the contacting surface 14 of the second pin 4 is set to the range 0.1-2 μm, including the limits. <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 adjacent links in the chain traveling direction. Are connected by a pair of pins (for example, see Patent Document 1).
Specifically, a pin insertion hole is formed in each link. The peripheral edges of the pin insertion holes of the links adjacent in the chain traveling direction are overlapped with each other, and a pair of pins are inserted into these pin insertion holes. The pair of pins can be brought into rolling contact with each other, and the pair of pins are in rolling contact with each other when adjacent links are bent relatively in the chain traveling direction. Further, tension (power) acts between the links adjacent in the chain traveling direction via a pair of pins.
Japanese Patent Laid-Open No. 8-31725

  In such a power transmission chain and a power transmission device including the same, it is required to further increase the practical efficiency and the transmission efficiency. An object of the present invention is to solve the above problems.

In practical use, the present inventor has optimized a mutual engagement state of a pair of pins in a power transmission chain that couples links adjacent to each other in the chain traveling direction using a pair of pins that can be brought into rolling contact with each other. The present invention has been conceived with the idea that it contributes to the improvement of the service life and the improvement of the transmission efficiency.
That is, the present invention provides a power transmission chain that includes a plurality of links arranged in the chain traveling direction, and in which the corresponding links are connected to each other so that power can be transmitted to each other using the first and second pins that are in rolling contact with each other. The arithmetic average roughness Ra of the contact surfaces of the first and second pins is set in the range of 0.1 μm or more and 2 μm or less, respectively.

  According to the present invention, by setting the arithmetic average roughness Ra of the contact surfaces of the first and second pins to 0.1 μm or more, the frictional engagement force between these contact surfaces can be sufficiently ensured. As a result, it is possible to suppress the occurrence of loss due to slippage between both pins, and the transmission efficiency can be extremely increased. In addition, by setting the arithmetic average roughness Ra of the contact surfaces of the first and second pins to 2 μm or less, these contact surfaces can be made sufficiently smooth to be brought into smooth contact with each other. As a result, the wear of the contact surfaces can be suppressed and the practical life can be further increased.

  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, and the first pin is a first link. The second pin is press-fitted and fixed in the front through-hole of the first link and is inserted into the front through-hole of the first link. It is preferable to be movably fitted into the through hole.

  Thereby, for example, when the first pin comes into contact with the sheave surface of the pulley as the power transmission target and transmits power, the second pin rolls and comes into sliding contact with the first pin. The links can be bent in the chain traveling direction. At this time, with respect to the first and second pins that are in contact with each other, the rolling contact component is large and the sliding contact component is extremely small. As a result, the first pin hardly rotates with respect to the sheave surface. It is possible to reduce friction loss and ensure higher transmission efficiency.

  In the present invention, the first and second pulleys each having a pair of conical sheave surfaces facing each other and the pulleys wound around these pulleys are engaged with the sheave surface as a power transmission target. The power transmission chain for transmitting power may be provided. In this case, it is possible to realize a power transmission device that is excellent in transmission efficiency and can be used practically for a long period of time.

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. 3 is a cross-sectional view taken along the line II-II in FIG.

Referring to FIGS. 1 and 2, the chain 1 includes a plurality of links 2, a first row 51, a second row 52, and a third row 53 as a pair of pins that are in rolling contact with each other. A plurality of first and second pins 3 and 4 are provided. The rolling sliding contact means a contact including at least one of a rolling contact and a sliding contact.
Referring to FIGS. 2 and 3, each link 2 is formed in a plate shape, and includes a front end portion 7 and a rear end portion 8 as a pair of end portions arranged in front and rear in the chain traveling direction X. A front through hole 9 and a rear through hole 10 are formed in the front end portion 7 and the rear end portion 8, respectively.

Each of the first row 51, the second row 52, and the third row 53 includes a plurality of links 2 arranged in the chain width direction W. In each of the first to third rows 51 to 53, the links 2 in the same row are aligned so that the positions in the chain traveling direction X are the same. The first to third rows 51 to 53 are arranged along the chain traveling direction X.
Each first pin 3 is a rod-like body extending in the chain width direction W. A pair of end portions of each first pin 3 protrudes in the chain width direction W from the link 2 disposed at the pair of end portions in the chain width direction W, respectively. Power transmission surfaces 5 and 6 for contacting (engaging) a sheave surface as a power transmission target are provided on a pair of end surfaces of each first pin 3. Since each first pin 3 contributes directly 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).

Each second pin 4 (also referred to as a strip or an interpiece) is a rod-like body formed of the same material as the first pin 3 and extending in the chain width direction W so as not to contact the sheave surface. It is slightly shorter than the first pin 3. With respect to the chain traveling direction X, each second pin 4 is formed thinner than the first pin 3.
Corresponding links 2 in the corresponding first to third rows 51 to 53 are connected to each other so as to be able to be bent and transmit power by using corresponding first and second pins 3 and 4.

  Specifically, the front through hole 9 of each link 2 of the first row 51 as the first link and the rear through hole 10 of each link 2 of the second row 52 as the second link are: The links 2 in the first and second rows 51 and 52 are connected to each other by the first and second pins 3 and 4 that are arranged in the chain width direction W and correspond to each other. Are coupled to be able to bend in the chain traveling direction X.

Similarly, the front through hole 9 of each link 2 in the second row 52 and the rear through hole 10 of each link 2 in the third row 53 correspond to each other side by side in the chain width direction W. The links 2 in the second and third rows 52 and 53 are connected to each other so as to be bent in the chain traveling direction X by the first and second pins 3 and 4 inserted through the through holes 9 and 10.
In FIG. 2, only one of the first to third columns 51 to 53 is shown, but the first to third columns 51 to 53 are arranged so as to repeat along the chain traveling direction X. Yes. The two rows of links 2 adjacent to each other in the chain traveling direction X are sequentially connected by corresponding first and second pins 3 and 4 to form an endless chain 1.

Each first pin 3 is loosely fitted in the front through-hole 9 of the corresponding link 2 so as to be able to move (rotate) relative to the link 2 and is press-fitted and fixed in the rear through-hole 10 of the corresponding link 2. Relative rotation with respect to the link 2 is regulated by (fitting).
Specifically, the first pin 3 is loosely fitted in the front through-hole 9 of each link 2 in the first row 51 so that relative rotation with respect to each link 2 in the first row 51 is enabled. The relative rotation of the second row 52 with respect to each link 2 is restricted by being press-fitted and fixed in the rear through-hole 10 of each link 2 in the second row 52. Similarly, the first pin 3 is loosely fitted in the front through hole 9 of each link 2 in the second row 52 and is press-fitted and fixed in the rear through hole 10 of each link 2 in the third row 53. Yes.

In addition, each second pin 4 is press-fitted and fixed (fitted) into the front through hole 9 of the corresponding link 2 to restrict relative rotation with respect to the link 2 and to the rear through hole 10 of the corresponding link 2. It is loosely fitted so that relative movement (rotation) with respect to the link 2 is possible.
Specifically, the second pin 4 is press-fitted and fixed in the front through-hole 9 of each link 2 in the first row 51, and relative rotation with respect to each link 2 in the first row 51 is restricted, It is loosely fitted in the rear through-hole 10 of each link 2 in the second row 52 so that relative movement (rotation) with respect to each link 2 in the second row 52 is possible. Similarly, the second pin 4 is press-fitted and fixed in the front through-hole 9 of each link 2 in the second row 52 and loosely fitted in the rear through-hole 10 in each link 2 in the third row 53. Yes.

With the above configuration, when the links 2 adjacent to each other in the chain traveling direction X bend each other (see FIG. 4), the corresponding first pins 3 are in rolling contact with the adjacent second pins 4. . Further, when the chain 1 is driven, tension is applied to the link 2 adjacent to the chain traveling direction X via the corresponding first and second pins 3 and 4.
Further, a locus of a contact line T (a straight line extending in a direction perpendicular to the paper surface in FIG. 4) between the first pin 3 and the corresponding second pin 4 with respect to the first pin 3 is substantially an involute curve. It is supposed to be.

Specifically, a contact surface 12 (surface) that can come into contact with the corresponding second pin 4 in the outer peripheral portion 11 of each first pin 3 is formed in a cross-sectional involute shape. Moreover, the contact surface 14 (surface) which can contact the corresponding 1st pin 3 among the outer peripheral parts 13 of each 2nd pin 4 is formed in a flat surface (cross-sectional linear shape).
That is, the contact surfaces 12 and 14 of each first pin 3 and the corresponding second pin 4 are opposed to each other in the chain traveling direction X.

When the links 2 adjacent to each other in the chain traveling direction X are bent, the contact surfaces 12 and 14 of the corresponding first and second pins 3 and 4 are relatively rolled and slidably contacted. Further, the tension applied to each link 2 acts on the corresponding link 2 adjacent to the chain traveling direction X via the contact surfaces 12 and 14 of the corresponding first and second pins 3 and 4.
The surface roughness of each of the contact surfaces 12 and 14 is expressed by, for example, an arithmetic average roughness Ra defined in JIS (Japanese Industrial Standard) B0601.

  Referring to FIG. 3, the feature of this embodiment is that the arithmetic average roughness Ra of the contact surface 12 of each first pin 3 and the contact surface 14 of each second pin 4 is 0. This is in the range of 1 μm or more and 2 μm or less. In the present embodiment, the first and second pins 3 and 4 are each formed by drawing, and the arithmetic average roughness Ra of the contact surfaces 12 and 14 is set to approximately 1 μm.

When the arithmetic average roughness Ra of the contact surface 12 of each first pin 3 and the contact surface 14 of each second pin 4 is less than 0.1 μm, the frictional engagement force between the corresponding contact surfaces 12 and 14 is It is difficult to secure enough. As a result, when the chain 1 is driven, a large slip occurs between the corresponding contact surfaces 12 and 14, and the rolling contact is obstructed, which may cause a large transmission loss.
Further, when the arithmetic average roughness Ra of the contact surface 12 of each first pin 3 and the contact surface 14 of each second pin 4 is larger than 2 μm, the roughness of each contact surface 12, 14 becomes too large. Accordingly, the corresponding contact surfaces 12 and 14 are not easily brought into contact with each other, and as a result, the wear of the contact surfaces 12 and 14 easily proceeds.

  For the above reason, the arithmetic average roughness Ra of the contact surface 12 of each first pin 3 and the contact surface 14 of each second pin 4 is set in the above range. In addition, regarding the surface of each first pin 3 and the surface of each second pin 4, the arithmetic average roughness Ra of the entire surface may be set to the above value, or the corresponding contact surface 12, For only 14, the arithmetic average roughness Ra may be set to the above value.

  As described above, according to the present embodiment, the arithmetic average roughness Ra of the contact surfaces 12 and 14 of the first and second pins 3 and 4 is set to 0.1 μm or more, thereby corresponding contact. A sufficient frictional engagement force between the surfaces 12 and 14 can be secured. As a result, it is possible to suppress the occurrence of loss due to slippage between the corresponding first and second pins 3 and 4, and the transmission efficiency can be extremely increased. Further, the arithmetic average roughness Ra of the contact surfaces 12 and 14 of the first and second pins 3 and 4 is set to 2 μm or less, respectively, so that the contact surfaces 12 and 14 are sufficiently smoothed and the corresponding contacts are made. The surfaces 12, 14 can be brought into smooth contact with each other. As a result, the wear of each contact surface 12, 14 can be suppressed and the practical life can be further increased.

  Further, each first pin 3 is loosely fitted into the front through hole 9 of the corresponding link 2 and press-fitted and fixed in the rear through hole 10 of the corresponding link 2, and each second pin 4 is further fixed to the corresponding link 2. The two front through holes 9 are press-fitted and fixed, and are loosely fitted into the corresponding rear through holes 10 of the link 2. Thereby, for example, when each first pin 3 contacts the sheave surface of a pulley as a power transmission target and transmits power, the corresponding second pin 4 rolls against the first pin 3. By the dynamic contact, the link 2 can be bent in the chain traveling direction X. At this time, with respect to the first and second pins 3 and 4 that are in contact with each other, the mutual rolling contact component is large and the sliding contact component is extremely small. It will not rotate, and friction loss can be reduced and higher transmission efficiency can be secured.

  Further, the trajectory of the contact line T between the corresponding first and second pins 3 and 4 substantially draws an involute shape, so that each first pin 3 sequentially bites into the sheave surface. It is possible to suppress the occurrence of string vibration-like movement in the chain 1 when it is rare. As a result, noise during driving of the chain 1 can be sufficiently reduced, which is suitable for a continuously variable transmission for automobiles that is strongly required to be quiet.

  Note that the first and second pins 3 and 4 may not be press-fitted into the corresponding through holes 9 and 10 of the corresponding link 2. Furthermore, the locus | trajectory of the mutual contact line T of the 1st and 2nd pins 3 and 4 does not need to draw an involute shape. Moreover, the structure which can engage both the 1st and 2nd pins 3 and 4 with the sheave surface of a pulley may be sufficient, and the structure which only the 2nd pin 4 can engage with a sheave surface may be sufficient. Furthermore, you may provide other members, such as a power transmission block, as a power transmission member engaged with the sheave surface of a pulley.

  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 opposing sheave surfaces 62a and 63a as power transmission targets. 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. Therefore, a fixed sheave 72 and a movable sheave 73 having sheave surfaces 72a and 73a as power transmission targets are provided. 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 outwardly from the conical surface of the sheave surfaces 72a and 73a (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 expanded by the movement of the movable sheave 73, and the power transmission surfaces 5, 6 of the first pin 3 of the chain 1 are directed inwardly of the conical surface of the sheave surfaces 72a, 73a. The winding radius of the output shaft 71 of the chain 1 is reduced while making sliding contact under boundary lubrication conditions.

As described above, according to the present embodiment, it is possible to realize a power transmission device that is excellent in transmission efficiency and quietness and that can be practically used for a long period of time.
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 the width | variety 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). .

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. It is sectional drawing which follows the II-II line of FIG. It is a partial cross section side view of the chain which shows the state where the links adjacent to a chain advancing direction bent. 1 is a perspective view schematically showing a main part configuration of a so-called chain type continuously variable transmission according to an embodiment of a power transmission device of the present invention. FIG. 6 is a partially enlarged cross-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)
2 links (first link, second link)
3 First pin 4 Second pin 9 Front through hole 10 Rear through hole 12 Contact surface (of the first pin) 14 Contact surface (of the second pin) 60 Drive pulley (first pulley)
70 Driven pulley (second pulley)
62a, 63a, 72a, 73a Sheave surface (power transmission target)
X Chain travel direction

Claims (3)

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 so as to be able to transmit power to each other using first and second pins that are in rolling contact with each other.
An arithmetic average roughness Ra of contact surfaces of the first and second pins with each other is set in a range of 0.1 μm or more and 2 μm or less, respectively. In Claim 1, the plurality of links include first and second links, each of which has a front through hole and a rear through hole arranged in the front and rear in the chain traveling direction,
The first pin is movably fitted into the front through hole of the first link and is press-fitted and fixed to the rear through hole of the second link. The second pin is the front through hole of the first link. A power transmission chain, wherein the power transmission chain is press-fitted and fixed to a rear through hole of the second link.   The first and second pulleys each having a pair of conical sheave surfaces facing each other, and wound around these pulleys and engaged with a sheave surface as a power transmission target to transmit power. A power transmission device comprising the power transmission chain according to claim 1 or 2.

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