JP2008215448A - Power transmission chain and power transmitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power transmission chain and a power transmission device capable of restraining a change in a contact position by elastic deformation of a pulley and a pin, by devising a shape of a pin end surface. <P>SOLUTION: A shape viewed from the chain advancing direction of both end surfaces in the longitudinal direction of a drive pin 14 coming into contact with a conical sheave surface of the pulley, is formed in a curved surface shape different between a radius of curvature R1 on the chain inner diameter side and a radius of curvature R2 on the chain outer diameter side, and is set to R1 < R2. <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. 7, 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. In this power transmission chain, the shape of the first pin in the longitudinal direction viewed from the chain traveling direction is curved so as to be a single curvature arc so that the pin contacts the sheave surface at the center. Yes.
JP 2005-233275 A

  In this type of power transmission chain, when the pin and the pulley are elastically deformed, the position of contact with the sheave surface of the pin changes, and the actual gear ratio may change from the designed gear ratio.

  An object of the present invention is to provide a power transmission chain and a power transmission device that can suppress a change in the contact position of the pin due to elastic deformation of the pin and the pulley by devising the shape of the pin end surface.

  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 at least one end face of the first pin and the second pin comes into contact with the pulley and power is transmitted by frictional force, the longitudinal direction both end faces of the pin in contact with the pulley from the chain traveling direction The viewed shape is a curved surface shape in which the curvature radius R1 on the inner diameter side of the chain and the curvature radius R2 on the outer diameter side of the chain are different, and R1 <R2.

  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 center of the radius of curvature is not on the axis of the pin, but on a line that is inclined from the axis by the same angle of inclination of the pulley. When the end of the pin comes into contact with the sheave surface of the pulley, it comes into contact with the center of the pin, but the pin and the pulley are slightly elastically deformed. At this time, for example, a pulley having an inclination angle of 11 ° As the angle is increased, the pin comes into contact with the sheave surface at a position closer to the inner diameter side of the chain than the center. When the contact position of the pin is shifted, a difference is generated between the designed gear ratio and the actual gear ratio. When the radius of curvature R1 on the inner diameter side of the chain is smaller than the radius of curvature R2 on the outer diameter side of the chain, the displacement of the contact position of the pin in the actual use state is smaller than that of the conventional pin where R1 = R2.

  The cross-sectional shape of each pin is the same as the conventional one. The planar shape of both ends in the longitudinal direction of the pin that contacts the pulley may be a curved shape with the same curvature in the forward half and the backward half, and the forward half protrudes more than the backward half It is good.

  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, since the curvature radius R1 on the inner diameter side of the chain is smaller than the curvature radius R2 on the outer diameter side of the chain, the displacement of the contact position of the pin when the pin or the pulley is elastically deformed is reduced. Therefore, the problem that the designed gear ratio is difficult to be obtained is avoided.

  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.

  The power transmission chain (1) is used in the V-type pulley type CVT shown in FIG. 3, and at this time, the fixed sheave (2a) and the movable sheave (2b) of the pulley (2) having the pulley shaft (2e). The end face of the drive pin (14) is not in contact with the conical sheave face (2c) (2d) of the pulley (2) in a state where the end face of the interpiece (15) is not in contact with each conical sheave face (2c) (2d). The power is transmitted by the friction force generated by the contact. The end surface of the drive pin (14) and the conical sheave surfaces (2c) (2d) of the pulley (2) are both inclined at a predetermined angle (usually 11 °).

  In FIG. 3, when the movable sheave (2b) of the drive pulley (2) at the position indicated by the solid line is moved toward and away from the fixed sheave (2a), the winding diameter of the chain (1) is as shown in FIG. As indicated by the chain line, it is large when approaching and small when separated. In the driven pulley (3), although not shown in the drawing, when the movable sheave moves in the opposite direction to the movable sheave (2b) of the drive pulley (2) and the winding diameter of the drive pulley (2) increases, the driven pulley When the winding diameter of (3) decreases and the winding diameter of the drive pulley (2) decreases, the winding diameter of the driven pulley (3) increases. As a result, from the U / D state (maximum deceleration state) where the winding diameter of the drive pulley (2) is minimum and the driven pulley (3) is maximum, the drive pulley (2 ) And the driven pulley (3) have the same winding diameter, and the drive pulley (2) has the largest winding diameter and the driven pulley (3) has the smallest winding diameter. (Maximum speed increase state) is obtained. The gear ratio obtained at this time is as follows. Designed.

  The shape of the drive pins (14) in contact with the conical sheave surfaces (2c) and (2d) of the pulley (2) as viewed from the chain traveling direction on both end surfaces in the longitudinal direction is as shown in an enlarged view in FIG. The curvature radius R1 on the chain inner diameter side and the curvature radius R2 on the chain outer diameter side are different curved surfaces (arcs), and the curvature radius R1 on the chain inner diameter side is smaller than the curvature radius R2 on the chain outer diameter side (R1 <R2 ) Has been made. Here, the center of the radius of curvature of each arc is not the axis O of the drive pin (14), but the line S inclined from the axis by the same angle as the inclination angle θ of the sheave surfaces (2c) (2d) of the pulley (2). It is provided above.

  When the drive pin (14) enters between the sheave surfaces (2c) and (2d) of the pulley (2), the drive pin (14) and the sheave surfaces (2c) and (2d) have a shape shown by a solid line in FIG. The shape changes to a two-dot chain line, and the sheave surfaces (2c) and (2d) of the pulley (2) are inclined in a direction in which the inclination angle is larger than 11 °, and the drive pin (14) is bent and the inclination angle is increased. Each of them is elastically deformed in a direction where θ becomes smaller than 11 °. As a result, the contact position of the drive pin (14) is shifted to the inner diameter side of the chain from the design value, as indicated by an arrow in FIG.

  According to the drive pin (14) shown in FIG. 4, the curvature radius R1 on the inner diameter side of the chain is smaller than the curvature radius R2 on the outer diameter side of the chain, so that the drive pin (14) and the pulley (2) are elastically deformed. However, the amount by which the designed contact position shifts to the inner diameter side of the chain is suppressed, and the problem that the designed gear ratio is difficult to be obtained is avoided.

  The end face shape of the drive pin (14) is not limited to two Rs as shown in FIG. 4, but as shown in FIG. 5, the curved surface of the radius of curvature R1 on the inner side of the chain and the outer side of the chain A curved surface with a radius of curvature R3 larger than R2 may be provided between the curved surface with a radius of curvature R2. By doing so, the surface pressure of the contact surface of the drive pin (14) is reduced, and accordingly, the load on the sheave surfaces (2c) and (2d) is also reduced. In order to reduce the surface pressure of the contact surface of the drive pin (14), the portion between the curved surface with the curvature radius R1 on the inner diameter side of the chain and the curved surface with the curvature radius R2 on the outer diameter side of the chain is limited to the curved surface. Instead, it may be a flat surface (the shape shown in FIG. 5 is a straight line).

  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, the drive pin (14) and the pulley (2) are elastically deformed, so that the drive pin (14) contacts the sheave surface (2c) (2d) at a position closer to the inner diameter side of the chain than its center. In this case, there is a possibility that the design gear ratio is difficult to be produced. However, since the curvature radius R1 on the inner diameter side of the chain <the curvature radius R2 on the outer diameter side of the chain, Can be minimized.

  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 front view showing a state in which the power transmission chain is attached to the pulley. FIG. 4 is a view showing the characteristic shape of the pin as seen from the chain traveling direction. FIG. 5 is a view seen from the chain traveling direction showing another example of the characteristic shape of the pin. FIG. 6 is a diagram schematically showing elastic deformation of the pin and the pulley. FIG. 7 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)

Claims (3)

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 shape of the pins in contact with the pulley in the longitudinal direction as viewed from the chain traveling direction is a curved surface shape in which the curvature radius R1 on the inner diameter side of the chain and the curvature radius R2 on the outer diameter side of the chain are different, and R1 <R2. A power transmission chain characterized by   2. A curved surface or plane having a curvature larger than R2 is interposed between a curved surface having a radius of curvature R1 on the inner diameter side of the chain and a curved surface having a radius of curvature R2 on the outer diameter side of the chain. Power transmission chain.   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 or 2.

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