JP2008208920A - Power transmission chain and power transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power transmission chain for preventing interference between a link and a pulley shaft when a pin is held between pulleys, and to provide a power transmission device. <P>SOLUTION: A drive pin 14 consists of a body 31 for supporting the links 11, and protruded portions 32 ranging from both ends. A chain inner diameter side face 32a of each protruded portion 32 is protruded to a chain inner diameter side beyond a chain inner diameter side face 31a of the body 31. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a power transmission chain, and more particularly to a power transmission chain and a power transmission device suitable for a continuously variable transmission (CVT) of a vehicle such as an automobile.

  As a continuously variable transmission for an automobile, as shown in FIG. 5, a drive pulley (2) provided on the engine side having a fixed sheave (2a) and a movable sheave (2b), a fixed sheave (3b) and a movable sheave (3a) and a driven pulley (3) provided on the drive wheel side and an endless power transmission chain (1) spanned between them, and a movable sheave (2b) (3a) by a hydraulic actuator The chain (1) is clamped with hydraulic pressure by moving it toward and away from the fixed sheave (2a) (3b), and this clamping force makes contact between the pulley (2) (3) and the chain (1). It is known that a load is generated and torque is transmitted by the frictional force of the contact portion.

As a power transmission chain, in Patent Document 1, a plurality of links having front and rear insertion portions through which pins are inserted, a front insertion portion of one link, and a rear insertion portion of another link correspond to the chain width direction. A plurality of first pins and a plurality of second pins arranged before and after connecting the links arranged in a row, and the first pin and the second pin are relatively in rolling contact and moved, so that the links can be bent in the longitudinal direction. It has been proposed that both ends of the first pin, which is longer than the second pin, come into contact with the pulley and power is transmitted by frictional force.
JP 2005-233275 A

  In the power transmission chain of Patent Document 1, when the first pin is sandwiched between the pulleys, the center portion thereof is elastically deformed so as to approach the pulley shaft. It was necessary to consider so as not to interfere.

  An object of the present invention is to provide a power transmission chain and a power transmission device in which interference between a link and a pulley shaft when a pin is sandwiched between pulleys is prevented.

  The power transmission chain according to the present invention includes a plurality of links having front and rear insertion portions through which pins are inserted, and links arranged in the chain width direction so that a front insertion portion of one link and a rear insertion portion of another link correspond to each other. A plurality of first pins and a plurality of second pins arranged before and after connecting each other are provided, and the first pin and the second pin are relatively rolled and brought into contact with each other, whereby the links can be bent in the length direction. In the power transmission chain in which power is transmitted by frictional force when both end faces of at least one of the first pin and the second pin are in contact with the pulley, the pin in contact with the pulley includes a main body portion that supports the link; It consists of projecting parts that are connected to both ends, and the chain inner diameter side surface of the projecting part is protruded closer to the inner diameter side of the chain than the chain inner diameter side surface of the main body part A.

  In the power transmission chain according to the present invention, at least one of the first pin and the second pin comes into contact with the pulley to transmit power by frictional force. In a chain in which one of the pins contacts the pulley, one of the first pin and the second pin is a pin that contacts the pulley when the chain is used in a continuously variable transmission ( In the following, it is referred to as “first pin” or “drive pin”, and the other is referred to as the pin that does not contact the pulley (interpiece or strip). It is called “interpiece”. The pin that contacts the pulley is sandwiched between the conical sheave surfaces of the pulley, and at this time, the central portion of the main body portion is elastically deformed so that it is bent most.

  The cross-sectional shape of the main body portion of the first pin is the same as the conventional one. The cross-sectional shape of the protruding portion is substantially the same as the cross-sectional shape of the main body portion, and the axis thereof is shifted to the inner diameter side of the chain with respect to the axis of the main body portion. The cross-sectional shape of the protruding portion is preferably slightly smaller than the cross-sectional shape of the main body portion so that the link can be easily fitted into the main body portion. The boundary surface between the main body portion and the projecting portion is, for example, a surface perpendicular to the axis, but may be an inclined surface and have various shapes as long as the link can be fitted into the main body portion. Can do.

  In the first pin, the end surface of the protruding portion comes into contact with the pulley, and this contact surface is displaced toward the inner diameter side of the chain from the virtual end surface (conventional contact surface) obtained by extending the main body portion in the axial direction. There is a gap between the inner diameter side of the chain of the link supported by the shaft and the shaft diameter of the pulley, which is larger than the conventional one by the displacement of the contact surface, and the first pin is sandwiched between the pulleys. In this case, the protruding portion is elastically deformed to reduce the deformation of the main body portion, thereby preventing the chain inner diameter side surface of the link supported by the main body portion from interfering with the pulley shaft. For this reason, since the position where the pin end surface contacts the pulley when the winding radius is minimized can be made smaller than the conventional diameter, the pulley conical surface can be used effectively, and the same gear ratio range can be secured. The length of the pulley cone necessary for the operation can be shortened.

  The first pin is manufactured by forging or the like, whereas the conventional method is a drawing process, and thus the processing cost can be reduced.

  One of the first pin and the second pin is fixed to the front insertion portion of one link and is movably fitted to the rear insertion portion of the other link, and the other is the front insertion portion of the one link. It is preferable that it is movably fitted in and fixed to a rear insertion portion of another link.

  For example, in a chain, three link rows composed of a plurality of links having the same phase in the width direction are arranged in the traveling direction (front-rear direction) to form one link unit, and the link unit composed of the three rows of link rows in the traveling direction. A plurality of links may be formed, and the number of links included in each link row may be different.

  The pin is fixed to the pin fixing portion by, for example, fitting and fixing the inner edge of the pin fixing portion and the outer peripheral surface of the pin by mechanical press-fitting. Alternatively, shrink fitting or cold fitting may be used. The fitting and fixing is preferably performed at the edges (upper and lower edges) of the portion orthogonal to the length direction of the pin fixing portion. After the fitting and fixing, a pre-tension is applied in the pre-tension applying step, so that an appropriate and residual compressive stress is equally applied to the pin fixing portion (pin press-fitting portion) of the link.

  The link is made of, for example, spring steel or carbon tool steel. The material of the link is not limited to spring steel or carbon tool steel, and may of course be other steel such as bearing steel. In the link, the front and rear insertion portions may be independent through holes (links with columns), and the front and rear insertion portions may be one through holes (links without columns). Appropriate steel such as bearing steel is used as the material of the pin.

  For example, the first pin and the second pin are formed as involute curved surfaces in which either one of the contact surfaces is a flat surface and the other contact surface is relatively rollable and movable. Moreover, you may make it each contact surface form a required curved surface for the 1st pin and the 2nd pin.

  In this specification, one end side in the length direction of the link is front and the other end side is rear, but this front and rear are for convenience, and the length direction of the link always coincides with the front and rear direction. It doesn't mean that.

  In the continuously variable transmission using the power transmission chain described above, each pulley includes a fixed sheave having a conical sheave surface and a movable sheave having a conical sheave surface facing the sheave surface of the fixed sheave. The chain is sandwiched between the sheave surfaces of both sheaves, and the movable sheave is moved by a hydraulic actuator, whereby the distance between sheave surfaces of the continuously variable transmission, and hence the winding radius of the chain, is changed.

  The power transmission device according to the present invention includes a first pulley having a conical sheave surface, a second pulley having a conical sheave surface, and power transmission spanned between the first and second pulleys. And a power transmission chain as described above.

  This power transmission device is suitable for use as a continuously variable transmission for a vehicle such as an automobile.

  According to the power transmission chain of the present invention, the pin tends to bend toward the inner diameter side of the chain, but the inner diameter side surface of the projecting portion is projected closer to the inner diameter side of the chain than the inner diameter side surface of the main body. Thus, even if the pin is curved, interference between the link supported by the protruding portion and the pulley shaft is prevented.

  Embodiments of the present invention will be described below with reference to the drawings. In the following description, the top and bottom refer to the top and bottom of FIG.

  FIG. 1 shows a part of a power transmission chain according to the present invention. The power transmission chain (1) has front and rear insertion portions (12) and (13) provided at predetermined intervals in the chain length direction. A plurality of links (11) and a plurality of drive pins (first pins) (14) and interpieces (second pins) (15) for connecting the links (11) arranged in the chain width direction so as to be bendable in the length direction ). The interpiece (15) is made shorter than the drive pin (14), and both face each other with the interpiece (15) disposed on the front side and the drive pin (14) disposed on the rear side.

  In the chain (1), three link rows composed of a plurality of links having the same phase in the width direction are arranged in the traveling direction (front-rear direction) to form one link unit, and the link unit composed of the three rows of link rows is the traveling direction. Are connected to each other. In this embodiment, one link unit includes a link row having nine links and two link rows having eight links.

  As shown in FIG. 2, the drive pin (14) is wider in the front-rear direction than the interpiece (15). Protruding edges (15a) and (15b) extending toward the drive pin (14) are provided on the upper and lower edges of the interpiece (15). A column part (21) is interposed between the front insertion part (12) and the rear insertion part (13) of the link (11), and the front insertion part (12) of the link (11) It consists of a drive pin movable part (16) to which the pin (14) is movably fitted and an interpiece fixing part (17) to which the interpiece (15) is fixed.The rear insertion part (13) is a drive pin (14 ) Are fixed to a drive pin fixing portion (18) and an interpiece movable portion (19) to which the interpiece (15) is movably fitted.

  When connecting the links (11) aligned in the chain width direction, the links (11) so that the front insertion part (12) of one link (11) and the rear insertion part (13) of the other link (11) correspond to each other ( 11) are overlapped, and the drive pin (14) is fixed to the rear insertion part (13) of one link (11) and movably fitted to the front insertion part (12) of the other link (11). The interpiece (15) is movably fitted to the rear insertion portion (13) of one link (11) and fixed to the front insertion portion (12) of the other link (11). The drive pins (14) and the interpiece (15) are relatively rolled and brought into contact with each other, whereby the links (11) can be bent in the length direction (front-rear direction).

  At the boundary between the drive pin fixing part (18) and the interpiece movable part (19) of the link (11), the upper and lower concave arcuate guide parts (19a) and (19b) of the interpiece movable part (19) are respectively provided. Upper and lower convex arc-shaped holding portions (18a) and (18b) for holding the drive pin (14) fixed to the continuous drive pin fixing portion (18) are provided. Similarly, the boundary between the interpiece fixing part (17) and the drive pin movable part (16) is connected to the upper and lower concave arcuate guide parts (16a) and (16b) of the drive pin movable part (16), respectively. Upper and lower convex arc-shaped holding portions (17a) and (17b) for holding the interpiece (15) fixed to the piece fixing portion (17) are provided.

  The locus of the contact position between the drive pin (14) and the interpiece (15) with respect to the drive pin (14) is an involute of a circle.In this embodiment, the contact surface of the drive pin (14) is The cross section has an involute shape having a base circle of radius Rb and center M, and the contact surface of the interpiece (15) is a flat surface (the cross-sectional shape is a straight line). As a result, when each link (11) moves from the straight portion of the chain (1) to the curved portion or from the curved portion to the straight portion, the drive pin (14) is fixed in the front insertion portion (12). The contact surface of the interpiece (15) moves in the drive pin movable portion (16) while rolling (including a slight sliding contact) with the contact surface of the interpiece (15), and the rear insertion portion (13 ), The interpiece (15) rolls into contact with the contact surface of the drive pin (14) with respect to the drive pin (14) fixed in the interpiece movable part (19) (slight sliding contact) Move). In FIG. 2, the portions indicated by reference signs A and B are lines (dots in the cross section) where the drive pin (14) and the interpiece (15) are in contact with each other in the straight portion of the chain (1). The distance between them is the pitch.

  As shown in FIG. 3, the drive pin (14) is formed in a stepped shape including a main body portion (31) for supporting the link (11) and projecting portions (32) connected to both ends in the axial direction. . The projecting portion (32) has an axis that is shifted toward the inner diameter side of the chain with respect to the axis of the main body portion (31), whereby the chain inner diameter side surface (32a) of the projecting portion (32) 31) is protruded toward the inner diameter side of the chain from the inner diameter side surface (31a) of the chain. The shape of the drive pin (14) shown in FIG. 2 shows the cross-sectional shape of the main body portion (31) of the drive pin (14), and the protruding portion (32) is also substantially the same shape. .

  This power transmission chain (1) is used in the V-type pulley type CVT shown in FIG. 4, and at this time, the fixed sheave (2a) and the movable sheave (2b) of the pulley (2) having the pulley shaft (2e). The end surface of the drive pin (14) is in contact with the conical sheave surface (2c) (2d) of the pulley (2) in a state where the end surface of the interpiece (15) is not in contact with each conical sheave surface (2c) (2d). The power is transmitted by the friction force generated by the contact. In FIG. 4, the protruding portion (32) of the drive pin (14) is in contact with the conical sheave surface (2c) (2d) of the pulley (2), and the chain inner diameter side surface (32a) of the protruding portion (32). Is protruded to the inner diameter side of the chain from the inner diameter side surface (31a) of the main body part (31), so even if the drive pin (14) is sandwiched between the sheave surfaces (2c) and (2d) and curved, The link (11) does not interfere with the pulley shaft (2e).

  In FIG. 4, when the drive pin (14) is changed to a conventional one and the position of the contact surface is the same as the contact position of the protruding portion (32) of the stepped drive pin (14), When the drive pin (44) having a shape is sandwiched between the sheave surfaces (2c) (2d) of the pulley (2) and curved, the link (11) interferes with the pulley shaft (2e) as shown in FIG. Therefore, it is necessary to move the contact position to the chain outer diameter side (upward in the drawing) of the pulley (2). Therefore, when using a conventional drive pin (44), the portion near the minimum diameter of the sheave surface (2c) (2d) will not be used, and the sheave surface (pulley cone) (2c) (2d) Is longer than when the stepped drive pin (14) is used. That is, by using the stepped drive pin (14), the pulley (2) can be made smaller than before, and a cost reduction effect can be obtained.

  In this power transmission chain (1), the required number of drive pins (14) and interpieces (15) are held vertically on an assembly jig, and then one or several links (11) are assembled together. Manufactured by press-fitting. This press-fitting is performed between the upper and lower edges of the drive pin (14) and the interpiece (15) and the upper and lower edges of the drive pin fixing part (18) and the interpiece fixing part (17). The cost is 0.005 mm to 0.1 mm. In this way, tension is applied (pre-tensioned) to the assembled chain (1).

  In the above power transmission chain (1), polygonal vibration occurs due to repeated vertical movement of the pin, which causes noise, but the drive pin (14) and the interpiece (15) are relatively in rolling contact. Because the locus of the contact position between the drive pin (14) and the interpiece (15) with respect to the drive pin (14) is an involute of a circle, both the contact surfaces of the drive pin and the interpiece are Compared with the case of a circular arc surface, vibration can be reduced and noise can be reduced. Further, since the drive pin (14) has a stepped shape, interference between the pulley shaft (2e) and the link (11) is surely prevented, and noise and vibration can be reduced also in this respect.

  When used in the CVT, the drive pin (14) and the interpiece (15) are guided by the movable parts (16) and (19) as described above to move in rolling contact. ), The drive pin (14) hardly rotates with respect to the sheave surfaces (2c) and (2d), the friction loss is reduced, and a high power transmission rate is secured.

FIG. 1 is a plan view showing a part of one embodiment of a power transmission chain according to the present invention. FIG. 2 is an enlarged side view of the link. FIG. 3 is a view of the pin as viewed from the traveling direction of the chain showing the characteristic shape of the pin. FIG. 4 is a front view showing a state in which the power transmission chain according to the present invention is attached to a pulley. FIG. 5 is a front view showing a state in which a conventional power transmission chain is attached to a pulley. FIG. 6 is a perspective view showing a continuously variable transmission.

Explanation of symbols

(1) Power transmission chain
(2) (3) Pulley
(2a) (3b) Fixed sheave
(2b) (3a) Movable sheave
(2c) (2d) Conical sheave surface
(11) Link
(12) Front insertion part
(13) Rear insertion part
(14) Drive pin (first pin)
(15) Interpiece (2nd pin)
(31) Body part
(31a) Chain inner diameter side
(32) Protruding part
(32a) Chain inner diameter side

Claims (2)

A plurality of links having front and rear insertion portions through which pins are inserted, and a plurality of links arranged before and after connecting links arranged in the chain width direction so that a front insertion portion of one link and a rear insertion portion of another link correspond to each other. The first pin and the plurality of second pins are provided, and the first pin and the second pin are relatively in rolling contact with each other, whereby the links can be bent in the length direction. In a power transmission chain in which at least one end surface of two pins is in contact with a pulley and power is transmitted by frictional force,
The pin that comes into contact with the pulley is composed of a main body portion that supports the link and a protruding portion that is connected to both ends of the main body. A power transmission chain characterized by that.   A power transmission chain comprising: a first pulley having a conical surface sheave surface; a second pulley having a conical surface sheave surface; and a power transmission chain spanned between the first and second pulleys. The power transmission device according to claim 1.

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