JP2009045668A - Method of manufacturing link for power transmission chain, power transmission chain, and power transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a link for a power transmission chain which can give residual compressive stress evenly, a power transmission chain, and a power transmission device. <P>SOLUTION: The method of manufacturing the link for the power transmission chain comprises a step 21 of rolling link material, a step 22 of giving tensile force to the link material after rolled so as to provide the residual compressive stress to the inside of the link material, and a step 23 of shaping the contour section 11a and front and rear pin insertion sections 12 and 13 of the link 11 by punching the link material with a press after providing the tensile force. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a link for a power transmission chain suitable for a continuously variable transmission (CVT) of a vehicle such as an automobile, a power transmission chain having the link, and a power transmission device.

As a power transmission chain suitably used in a continuously variable transmission for automobiles, Patent Document 1 discloses a plurality of links having front and rear insertion portions through which pins are inserted, a front insertion portion of one link, and other links. A plurality of first pins and a plurality of second pins arranged before and after connecting the links arranged in the chain width direction so as to correspond to the rear insertion portion are provided, and the first pin and the second pin are relatively rolled and moved in contact with each other. Thus, a link that can be bent in the length direction between links has been proposed.
JP 2005-233275 A

  In the power transmission chain of Patent Document 1, pre-tension is applied to the link in a state where the chain is assembled. As a result, the application of residual compressive stress to the link may vary.

  It is an object of the present invention to provide a power transmission chain link manufacturing method, a power transmission chain, and a power transmission device that can uniformly apply residual compressive stress.

  A power transmission chain link manufacturing method according to the present invention is a method of manufacturing a power transmission chain link having front and rear insertion portions through which pins are inserted, and includes a step of rolling the link material and a residual compression inside the link material. It includes a step of applying tension to the link material after rolling so that stress is applied, and a step of punching out the link material after applying tension with a press to form the shape of the contour portion of the link and the front and rear insertion portions. It is characterized by this.

  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 either 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 (hereinafter referred to as a pin). Is referred to as a “first pin” or “pin”), and the other pin is referred to as a pin that does not contact the pulley (interpiece or strip). ").

  In this specification, the chain direction is referred to as the front-rear direction, and the direction perpendicular thereto is referred to as the up-down direction.

  The step of forming the contour portion of the link and the shape of the front and rear insertion portion by pressing may be performed simultaneously with the formation of the contour portion of the link and the formation of the front and rear insertion portion, and the step of forming the contour portion of the link and the front and rear insertion portion You may carry out by a different process like the process of forming.

  The pre-tension is preferably such that the maximum principal stress generated in the link is equal to or greater than the elastic limit stress of the link. By doing so, the link is plastically deformed by the pretension, residual compressive stress is applied to the inside of the link, and fatigue durability performance is improved.

  For example, the link is made of spring steel or carbon tool steel. The material of the link is not limited to spring steel or carbon tool steel, but may be other steel such as bearing steel. The first pin and the second pin may have different cross-sectional shapes or the same shape. In addition, the front and rear insertion portions of the links may be independent through holes (links with columns), and the front and rear insertion holes may be one through holes (links without columns). Appropriate steel such as bearing steel is used as the material of the pin.

  Conventionally, in the chain manufacturing process, the pre-tensioning process is performed after the chain is assembled. And the pretension was given to the link in the pretension provision process, and the durability of the chain was improved by giving residual compressive stress to a link. However, when pre-tensioning is applied with a chain, the stress is caused by the complicated link shape, and the target residual compressive stress cannot be applied to the entire link, and a certain part (the part where the pin is press-fitted ( It can be applied only to a very narrow range) of the pin press-fit portion). In addition, even in a very narrow area of the pin press-fit part, the residual compressive stress is applied depending on the stress concentration rather than the stress. Residual compressive stress was not obtained.

  When the link is manufactured by the manufacturing method of the present invention, the pretensioning step is performed before the contour portion of the link is formed by the press. And since the pretension is applied to the link material in the pretension applying step, the uniform residual compressive stress can be applied to the entire link including the periphery of the front and rear insertion portion.

  The power transmission chain using the link manufactured by the manufacturing method of the present invention includes, for example, 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 of another link. A plurality of first pins and a plurality of second pins arranged before and after connecting the links arranged in the chain width direction so as to correspond to each other, and the first pin and the second pin are relatively in rolling contact and moved It is assumed that the links can be bent in the length direction.

  For example, the first pin and the second pin are formed in a required curved surface so that one of the rolling contact surfaces is a flat surface and the other rolling contact surface is relatively rolling and movable. Moreover, you may make it a rolling contact surface form a required curved surface for the 1st pin and the 2nd pin. In any case, two types of rolling contact surface shapes of each pin (for example, those having a relatively large curvature and those having a relatively small curvature) are formed, so that the locus of the rolling contact movement is different. There may be two types of pin pairs. The locus of the contact position between the first pin and the second pin is, for example, an involute curve.

  In this power transmission chain, the pin (interpiece) is fixed to the front and rear insertion portion by, for example, fitting and fixing the inner edge of the insertion portion and the outer peripheral surface of the pin by mechanical press-fitting. Alternatively, shrink fitting or cold fitting may be used. A pin and an interpiece are fitted to one insertion portion so as to face each other in the length direction of the chain, and either one of them is fitted and fixed to the peripheral surface of the insertion portion of the link.

  In such a power transmission chain, it is important to reliably apply a pretension (apply a residual compressive stress of a required magnitude) to the pin press-fitting portion (pin fixing portion) of the link. According to the said manufacturing method, the link suitable for such a power transmission chain can be obtained, and the power transmission chain comprised by the link obtained in this way can have the outstanding durability.

  In the above power transmission chain, one of the pins (interpiece) is shorter than the other pin (pin), the end surface of the longer pin contacts the conical sheave surface of the pulley of the continuously variable transmission, It is preferable that power is transmitted by the frictional force due to this contact. 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. By moving the shaft with a hydraulic actuator, the wrapping radius of the chain changes according to the distance between sheave surfaces of the continuously variable transmission, and a 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 (CVT) of a vehicle such as an automobile.

  According to the method for manufacturing a link for a power transmission chain of the present invention, the residual compressive stress is applied to the inside of the link material before the step of punching the link material after the tension is applied with a press to form the shape of the contour portion and the front and rear insertion portion of the link. By applying the process of applying tension to the link material after rolling so as to be applied, it is possible to apply a uniform residual compressive stress to the link, thus improving the fatigue life of the link and improving the durability of the chain. be able to.

  Embodiments of the present invention will be described below with reference to the drawings. In the following description, the right side of FIG. 2 will be referred to as the front, the left side of FIG.

  FIG. 1 shows a part of a power transmission chain in which a link (11) manufactured by the manufacturing method of the present invention is used. The power transmission chain (1) is spaced at a predetermined interval in the chain length direction. A plurality of pins (first pins) for connecting a plurality of links (11) having provided front and rear insertion portions (12) and (13) so that the links (11) arranged in the chain width direction can be bent in the length direction. (14) and an interpiece (second pin) (15).

  FIG. 2 shows the completed link (11). The link (11) includes front and rear insertion portions (12) and (13) through which the pins (14) and (15) are inserted, and one link (11). A plurality of first pins (pins) arranged before and after connecting the links (11) arranged in the chain width direction so that the front insertion part (12) of the other link (11) corresponds to the rear insertion part (13) of the other link (11) ) (14) and a plurality of second pins (interpieces) (15), and the first pin (14) and the second pin (15) are relatively in rolling contact with each other to move the link (11). It is possible to bend them in the length direction. The interpiece (15) is made shorter than the pin (14), and the two (14) and (15) are opposed to each other with the pin (14) on the rear side and the interpiece (15) on the front side. ing.

  The front insertion part (12) is movable in an interpiece, in which a pin fixing part (12a) to which a pin (shown by a solid line) (14) is fixed and an interpiece (15) (shown by a two-dot chain line) are movably fitted together The rear insertion part (13) is composed of a part (12b), and the pin insertion part (13) is movably fitted with a pin (indicated by a two-dot chain line) (14) and an interpiece (15) (indicated by a solid line). It consists of an interpiece fixing part (13b) to which is fixed.

  The locus of the contact position between the pin (14) and the interpiece (15) with respect to the pin (14) is an involute curve.In this embodiment, the rolling contact surface (14a) of the pin (14) is The cross section has an involute shape having a base circle of radius Rb and center M, and the rolling contact surface (15a) 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 part of the chain (1) to the arc part or from the arc part to the straight part, the interpiece (15) is movable in the front insertion part (12). The rolling contact surface (15a) moves to the rolling contact surface (14a) of the pin (14) while being in rolling contact (including some sliding contact) with respect to the pin (14) in the fixed state in the part (12b). In the rear insertion portion (13), the rolling contact surface (14a) is in rolling contact with the rolling contact surface (15a) of the interpiece (15) with respect to the interpiece (15) in which the pin (14) is fixed ( It moves in the pin movable part (13a) while including a slight sliding contact. The locations 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 It is.

  The method of manufacturing the link (11) according to the present invention is a method of manufacturing the link (11) shown in FIG. 2, and includes a step (21) of rolling the link material, as shown in FIG. A step of applying pretension to the link material (22), and a step of punching the link material with a press to form the shape of the contour portion (11a) of the link (11) and the front and rear insertion portions (12) (13) (23) Is included.

  The step (22) of applying pretension to the rolled link material can be performed, for example, by pulling the link material with a tension applying device (not shown).

  The step (23) of forming the shape of the contour portion (11a) of the link (11) and the front and rear insertion portions (12) and (13) by pressing may be performed simultaneously, and the contour portion (11a of the link (11) ) And a step of forming the front and rear insertion portions (12) and (13) may be performed in different steps.

  The link (11) manufactured by the manufacturing method of the present invention is pre-tensioned in the pre-tension applying step (22) before the step (23) of forming the contour portion (11a) of the link (11). Therefore, when the front and rear insertion portions (12) and (13) are formed, a uniform residual compressive stress is applied to the entire link including the periphery of the front and rear insertion portions (12) and (13).

  After the power transmission chain (1) according to the present invention has been subjected to the above steps (21), (22), and (23), the necessary number of pins (14) and the interpiece (15) are vertically held on the table. The link (11) is manufactured by a step (24) in which one or several links (11) are press-fitted together. 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 (12a) and the interpiece fixing part (13b). It is set to 0.005 mm to 0.1 mm. As a result, the pin (14) and the interpiece (15) are fixed with equal stress in the pin fixing portion (12a) and the interpiece fixing portion (13b), and in each of the upper and lower edges thereof. . Therefore, since the uniform residual compressive stress is applied to the link (11), the fatigue life of the link (11) can be improved and the durability of the chain can be improved.

  The power transmission chain described above is used as a vehicle automatic transmission shown in FIGS. 4 and 5. As shown in FIG. 5, the continuously variable transmission has a fixed sheave (2a) and a movable sheave (2b), a drive pulley (2) provided on the engine side, 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 the movable sheave (2b) (3a) is fixed by a hydraulic actuator By approaching and separating from the sheaves (2a) and (3b), the chain (1) is clamped and brought into contact with hydraulic pressure, and torque is transmitted by the frictional force of the contact portion. At this time, for example, the interpiece (second pin) (15) is made shorter than the pin (first pin) (14), and the end face of the interpiece (15) is fixed and movable with the fixed sheave (2a) of the pulley (2). 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 the sheave (2b). Power is transmitted by the frictional force caused by. As described above, since the pin (14) and the interpiece (15) are in rolling contact movement, the pin (14) hardly rotates with respect to the sheave surfaces (2c) (2d) of the pulley (2). Thus, 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 in which a link manufactured by the method for manufacturing a link for a power transmission chain according to the present invention is used. FIG. 2 is an enlarged side view of a link (completion drawing). FIG. 3 is a flowchart showing steps in the method for manufacturing a link for a power transmission chain according to the present invention. FIG. 4 is a front view showing a state in which the power transmission chain is attached to the pulley in the continuously variable transmission. FIG. 5 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
(11a) Contour
(12) Front insertion part
(13) Rear insertion part
(14) Pin (1st pin)
(15) Interpiece (2nd pin)
(21) Rolling process
(22) Pretensioning process
(23) Link formation process
(24) Press-in process

Claims (3)

  A method of manufacturing a link for a power transmission chain having a front and rear insertion portion through which a pin is inserted, the step of rolling the link material, and the link material after rolling so that residual compressive stress is applied inside the link material. A method for manufacturing a link for a power transmission chain, comprising: a step of applying tension; and a step of punching a link material after applying tension to form a contour portion of the link and a shape of a front and rear insertion portion. .   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. In the power transmission chain, 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 so that the links can be bent in the longitudinal direction. A power transmission chain, wherein the link is manufactured by the manufacturing method according to claim 1.   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 2.

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