JP2008144825A - Power transmission chain and power transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power transmission chain and a power transmission device further reducing noise and vibration by optimizing the rolling contact face shape and the offset quantity of a pin having influence on a pin end-face contact shape. <P>SOLUTION: The pin 14 having a rolling contact face 14a of an involute curve is composed of two kinds having different involute curve radii Rb, so that two kinds of offset quantities are set for the pin end-face shape to contact the conical face of a pulley. The combinations of large/small radii Rb of the involute curve and large/small offset quantities for each pin 14 are limited to any of large Rb-large offset, large Rb-small offset, and small Rb-small offset. <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. 6, 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 that connect the links arranged in a row in a longitudinal direction so as to be fixed to the front insertion portion of one link and movable to the rear insertion portion of another link The first pin that is fitted and the second pin that is movably fitted to the front insertion portion of one link and fixed to the rear insertion portion of the other link are relatively rolled and moved in contact with each other. It is possible to bend in the length direction, and to reduce noise and vibration, two or more types of link pitch length, pin rolling contact surface shape, pin pulley contact position (offset amount), etc. It is proposed that It is.
JP 2006-097844 A

  In the power transmission chain shown in Patent Document 1, when there are two types of pin rolling contact surface shapes and two types of offset amounts, four types of pins including all of these combinations are used. However, since the rolling contact surface shape of the pin and the offset amount both affect the shape of the pin end surface contacting the pulley surface, it is best to use all four types to reduce noise and vibration. It may not be a combination of

  An object of the present invention is to provide a power transmission chain and a power transmission device in which noise and vibration are further reduced by optimizing the pin rolling contact surface shape and the offset amount that affect the pin end surface contact shape. is there.

  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 a power transmission chain in which either one of the first pin and the second pin has a rolling contact surface that is an involute curve and the other rolling contact surface is a flat surface, the rolling contact surface is an involute curve. Consists of two types with different radius Rb of the involute curve, and two types of offset amounts are set for the pin end surface shape that contacts the conical surface of the pulley. The combination of the magnitude of the radius Rb of the involute curve and the magnitude of the offset amount for each pin is limited to one of Rb large-offset large, Rb large-offset small, and Rb small-offset small. To do.

  The pulley surface is, for example, conical and has an inclination angle of, for example, 11 °, and the pin end surface is formed into a curved surface with an inclination angle corresponding thereto. As a result, the “center” of the pin has the center of the cross-sectional shape (centroid) and the center of the region where the end surface contacts the pulley (centroid of the contact region, hereinafter referred to as “contact center point”), This difference is called an offset amount. The offset amount can be set to a different value by changing the grinding amount at the time of processing the end surface of the pin having the same cross-sectional shape. Pins with different offset amounts shift the sound generation period and contribute to distributing sound energy to different frequency bands, thereby reducing the sound pressure level peak and reducing noise and vibration. It becomes possible.

  The small offset is preferably no offset (the contact center point coincides with the center of the cross-sectional shape), and the large offset is provided so that the contact center point moves to the chain outer diameter side.

  Pins whose rolling contact surface is an involute curve (hereinafter referred to as “first pin” or “pin”) contact the conical sheave surface of the pulley of the continuously variable transmission to transmit power by frictional force. To do. The other pin is a pin that is not in contact with the pulley (referred to as an interpiece or a strip, and hereinafter referred to as a “second pin” or an “interpiece”). The second pin preferably has a shape narrower than that of the first pin. In this case, the upper and lower edges of the second pin may be provided with protruding edges.

  One of the first pin and the second pin is fixed to a pin fixing portion provided at a front portion of a front insertion portion of one link and is movable at a front portion of a rear insertion portion of another link The other side is movably fitted into a pin movable part provided on the rear part of the front insertion part of one link and the rear part of the rear insertion part of the other link. It is preferable that it is fixed to a pin fixing part provided in.

  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, but 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.

  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.

  Each pulley is composed of 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. Is moved by the hydraulic actuator, the distance between the sheave surfaces of the continuously variable transmission, that is, the wrapping radius of the chain is changed, and the continuously variable transmission can be performed with smooth movement.

  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 device of the present invention, the pin whose rolling contact surface is an involute curve consists of two types having different radius Rb of the involute curve, and there are two types of pin end surface shapes that contact the conical surface of the pulley. Since the offset amount is set, noise and vibration can be reduced. Further, regarding the combination of the magnitude of the radius Rb of the involute curve and the magnitude of the offset amount for each pin, Rb large-offset large, Rb large-offset small And Rb small-offset is limited to either small offset, so that the contact area of the pin is prevented from protruding from the cross-sectional shape of the pin, and the surface pressure is maximized and hence stress concentration is prevented. The noise and vibration reduction effect can be obtained and the durability of the chain can be improved.

  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 pins (first pin) (14) and an interpiece (second pin) (15) for connecting the links (11) arranged in the chain width direction so as to be bendable in the length direction And. The interpiece (15) is made shorter than the pin (14), and both are opposed to each other with the interpiece (15) disposed on the front side and the 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 front insertion part (12) of the link (11) has a pin movable part (16) to which the pin (14) is movably fitted and an interpiece fixing to which the interpiece (15) is fixed. The rear insertion part (13) consists of a pin fixing part (18) to which the pin (14) is fixed and an interpiece movable part (19) to which the interpiece (15) is movably fitted. Become.

  Each pin (14) is wider in the front-rear direction than the interpiece (15), and the upper and lower edges of the interpiece (15) have protruding edges (15a) extending to the respective pins (14) side. ) (15b).

  In FIG. 2, the portions indicated by reference signs A and B are lines (points in the cross section) where the pin (14) and the interpiece (15) are in contact with each other in the straight portion of the chain (1), and the distance between AB. Is the pitch.

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

  The locus of the contact position between the pin (14) and the interpiece (15) with respect to the pin (14) is an involute of the circle, and in this embodiment, the rolling contact surface (14a) of the pin (14) However, the cross section has an involute shape having a basic circle with a radius Rb and a center M, and the rolling contact surface (15c) 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 pin (14) is fixed in the front insertion portion (12). The rolling contact surface (14a) of the piece (15) moves in the pin movable part (16) while being in rolling contact (including some sliding contact) with the rolling contact surface (15c) of the interpiece (15). In the rear insertion part (13), the rolling contact surface (15c) of the interpiece (15) is in contact with the pin (14) in contact with the pin (14) fixed in the interpiece movable part (19). It moves with rolling contact (including some sliding contact) on the surface (14a).

  In the above power transmission chain (1), polygonal vibration is caused by repeated vertical movement of the pin, which causes noise, but the pin (14) and the interpiece (15) are relatively rolled and moved in contact. In addition, since the locus of the contact position between the pin (14) and the interpiece (15) with respect to the pin (14) is an involute of the circle, the rolling contact surfaces of the pin and the interpiece are both arcuate surfaces. Compared with some cases, vibration can be reduced and noise can be reduced.

  In order to further reduce noise and vibration, by arranging two or more types of links (11) and pins (14) with different shapes at random, the period of sound generation is shifted and the sound energy is reduced. It is preferable that the sound pressure level peaks are reduced by being distributed in different frequency bands.

  The end surface shape of the pin (14) contacting the conical sheave surface (2c) (2d) of the pulley (2) is formed into an appropriate curved surface by, for example, crowning. With respect to the contact center point, an appropriate offset amount can be set at the time of processing. Therefore, noise and vibration can be reduced by setting two types of offset amounts.

  In FIG. 3, in the pin (P1) indicated by the solid line, the contact region (C1) when the offset amount is 0 is indicated by the solid line in FIG. When the offset amount is increased and the contact center point is moved in the chain outer diameter direction, a contact region (C2) as indicated by a broken line in the figure is obtained. Since the contact areas (C1) and (C2) are smaller than the cross-sectional area of the pin (P1), the contact areas (C1) and (C2) usually do not protrude from the cross-sectional shape of the pin (P1). However, as shown by the two-dot chain line in FIG. 3, when the contact center point is moved greatly in the outer diameter direction of the chain in the pin (P2) having a small radius of the involute curve, the contact region (C3) is It may happen that it protrudes from the cross-sectional shape of (P2).

  Therefore, in the power transmission chain according to the present invention, the radius Rb of the involute curve of the pin (14) has a larger radius Rb of the involute curve shown in FIG. 4 (a) and the radius Rb of the involute curve shown in FIG. 4 (b). Are used, and two types of offsets are set for the end shape of the pin (14). In this case, 2 × 2 = 4 types of combinations are possible. Rb small-offset large and Rb large-offset large, Rb large-offset small, and Rb small-offset with respect to the combination of the radius Rb of the involute curve for each pin 14 and the large amount of offset. Limited to small one.

  That is, of the four types of combinations, those that most likely cause the pin end surface contact area to protrude from the pin cross-sectional shape are excluded. For this reason, even if the radius of the involute curve is changed or the curvature of the pin end surface is changed, the surface pressure maximization (stress concentration) that occurs when the pin end surface contact area protrudes from the pin cross-sectional shape is prevented. Thus, the problems of reduced durability and increased noise and vibration are reliably prevented. And the noise and vibration reduction effect is enhanced by randomly arranging the three types of combination pins (14).

  This power transmission chain (1) holds the required number of pins (14) and interpieces (15) vertically on the table, and then press-fits one or several links (11) one by one. It is manufactured by going. This press-fitting is performed between the upper and lower edges of the pin (14) and the interpiece (15) and the upper and lower edges of the pin fixing part (18) and the interpiece fixing part (17). It is set to 0.005 mm to 0.1 mm. In this way, tension is applied (pre-tensioned) to the assembled chain (1).

  The power transmission chain described above is used in the CVT shown in FIG. 6. At this time, as shown in FIG. 5, the end face of the interpiece (15) is fixed to the fixed sheave (2a) of the pulley (2) and the movable sheave. The end surface of the pin (14) is in contact with the conical sheave surface (2c) (2d) of the pulley (2) without contacting the conical sheave surface (2c) (2d) of (2b). Power is transmitted by the frictional force. As described above, the pin (14) and the interpiece (15) are guided by the movable parts (16) and (19) to move in rolling contact with each other, so that the sheave surfaces (2c) (2d) of the pulley (2) On the other hand, the pin (14) hardly rotates, the friction loss is reduced, and a high power transmission rate is secured. When the movable sheave (2b) of the drive pulley (2) at the position indicated by the solid line is moved closer to or away from the fixed sheave (2a), the winding diameter of the chain (1) is indicated by a chain line in the figure. As shown, it is large when approaching and small when separating. 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, on the basis of the state where the gear ratio is 1: 1 (initial value), the winding diameter of the drive pulley (2) is minimum and the winding diameter of the driven pulley (3) is maximum U / D. A state is obtained, and an O / D state in which the winding diameter of the drive pulley (2) is maximum and the winding diameter of the driven pulley (3) is minimum is obtained. Even when the winding diameter is minimum, there is a slight gap between the pulley shaft (2e) and the surface of the link (11) on the chain inner diameter side.

  In the above, the link (11) is not distinguished, but two types of links (11) with different pitch lengths can be used as the link (11). In addition, there are two types of pin lengths. Of course, other means for dispersing the sound may be combined.

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 diagram illustrating the cross-sectional shape and the end surface contact shape of the pin. FIG. 4 is a diagram showing the shape of the pins used in the present invention. FIG. 5 is a front view showing a state in which the power transmission chain is attached to the 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) Pin (1st pin)
(14a) Involute rolling contact surface
(15) Interpiece (2nd pin)
(15c) Flat rolling contact surface

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 aligned 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 longitudinal direction. In the power transmission chain in which either one of the two pins has an involute curved contact surface and the other rolling contact surface is a flat surface.
The pin whose rolling contact surface is an involute curve consists of two types with different radius Rb of the involute curve, and two types of offset amounts are set for the pin end surface shape that contacts the conical surface of the pulley. Power transmission characterized by being limited to one of Rb large-offset large, Rb large-offset small, and Rb small-offset small regarding the combination of the magnitude of radius Rb of the involute curve with respect to the pin and the magnitude of the offset amount 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.

Images