JP2011200874A - Method for manufacturing power transmission chain - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a power transmission chain which can prevents damage of pins when pretension is increased and more suitable residual compression stress is applied to a link.SOLUTION: The method includes a step of winding an endless chain between a first pulley 32 for pretension application and a second pulley 33 for pretension application to apply pretension to a chain 1. In the pretension application step, attachable/detachable protective members 37 are mounted on both the end parts of each pin 14 to apply the pretension.

Description

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

  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. Those that can be bent in the length direction have been proposed.

  In this type of power transmission chain, in order to improve durability, tension is applied (pre-tensioned) to the chain in advance in the manufacturing process, and an appropriate residual compressive stress is applied to the link. ing.

  In the conventional pretensioning device, the sheave surfaces facing each other of the pretensioning pulleys are conical surfaces (the cross-sectional shape is a straight line) from the idea of matching with the continuously variable transmission (actual machine) used. . In order to apply an appropriate residual compressive stress to the link by the pretension applying device, it is preferable to set the pretension to a predetermined value or more.

  Therefore, Patent Document 1 proposes that the sheave surfaces facing each other of the pretension applying pulleys have a concave shape corresponding to the convex curved portion of the pin end surface.

JP 2008-110378 Gazette

  According to the above-mentioned Patent Document 1, it is possible to prevent the pin from being damaged when the pretension is increased to give a more appropriate residual compressive stress to the link, but the sheave surface shape of the pretensioning pulley is actually used. Since it is different from the shape of the pulley to be used, there is a problem that it takes time to manufacture the pulley for applying the pretension.

  The object of the present invention is to make the sheave surface shape of the pretensioning pulley the same as the shape of the pulley actually used when applying a more appropriate residual compressive stress to the link by increasing the pretension, An object of the present invention is to provide a method of manufacturing a power transmission chain that can prevent damage to pins.

  A power transmission chain manufacturing method according to the present invention is a power transmission chain manufacturing method comprising a plurality of links and a plurality of pins connecting the links, and used by being wound between two pulleys. A step of wrapping an endless chain between the first pulley and the second pretension applying pulley to apply pretension to the chain. In the pretension applying step, a removable protective member is attached to each pin. It is characterized in that it is attached to both ends and pretension is applied.

  In the conventional pretensioning process, the protective member is not used, and the pin end surface is in direct contact with the sheave surface of the pulley. However, in the method of manufacturing a power transmission chain according to the present invention, the pin end surface is interposed via the protective member. Touch the sheave surface of the pulley. The protective member is attached to each pin before pre-tensioning, removed after pre-tensioning, and used repeatedly. The protective member is made of a material softer than the pin (the hardness of the protective member is lower than the hardness of the pin). As the material of the pin, appropriate steel such as bearing steel is used, and the protection member is appropriately changed corresponding to the material of the pin. If the HRC hardness difference between the protective member and the pin is about 1 to 2, the pin can be protected.

  The first pretension imparting pulley and the second pretension imparting pulley are made of the same material as the pulley of the continuously variable transmission in which the chain is used (for example, structural steel). The sheave surface shape of each pretensioning pulley is the same as the pulley of a continuously variable transmission in which a chain is used, for example, a conical surface with a sheave surface inclination angle of 8 to 13 ° (usually 11 °). It is said. The material and shape of the pretensioning pulley are not particularly limited, but the pretensioning pulley can be manufactured by matching the material of the pretensioning pulley and the shape of the sheave surface to the actual continuously variable transmission. Becomes easy.

  The protective member is made of the same material as the pin, and it is preferable that the HRC hardness is lower by 1 or more than the pin by changing the heat treatment conditions. For the same material (steel), it is possible to set the HRC hardness to a predetermined value by changing the heat treatment conditions. By changing only the heat treatment conditions, the production of the protective member becomes easy, The pin end face can be reliably protected.

  The protective member is, for example, a cylindrical shape composed of a peripheral wall and an end wall, the inner peripheral surface of the peripheral wall is shaped along the outer peripheral surface of the pin end, and the inner surface of the end wall is shaped along the pin end surface, The outer surface of the wall has the same shape as the pin end surface shape, and the outer peripheral surface of the peripheral wall has an arbitrary shape (for example, a cylindrical surface).

  The power transmission chain obtained by the manufacturing method according to the present invention is used in a continuously variable transmission in which a winding diameter is changed in a stepless manner with a change in a distance between sheaves of each pulley and a stepless speed change is performed. Suitable for

  The pretensioning device for performing pretensioning can be, for example, a model of a continuously variable transmission (actual machine). For example, the pretensioning device includes a fixed sheave having conical surface sheave surfaces and a fixed sheave. A first pulley comprising a movable sheave, and a second sheave comprising a fixed sheave and a movable sheave each having a conical sheave surface, and by moving the movable sheave toward and away from the fixed sheave, It is supposed to clamp the chain. The pretension applying device does not need to simulate an actual machine. For example, the movable sheave of each pulley is fixed, and the pretension applying device has a pair of fixed sheaves each having a conical sheave surface. A first pulley opposed at a first interval; and a second pulley having a pair of fixed sheaves each having a conical sheave surface opposed at a second interval. The chain may be tensioned by approaching or separating the distance between the axes of the first pulley and the second pulley while rotationally driving the pulley. Also, three pulleys with fixed sheave surfaces are used, a pair of upper pulley and one lower pulley are arranged to form a triangle, and an endless chain is wound around these three pulleys to give tension. You may make it do. Furthermore, when the tension is applied, the distance between the pulleys may be changed, but the tension may be applied by pressing a predetermined position of the chain with an auxiliary roller.

  The above manufacturing method is suitable for manufacturing various power transmission chains, but includes 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 The link can be bent in the length direction, and one of the first pin and the second pin is fixed to the front insertion portion of one link and can be moved to the rear insertion portion of the other link. The other is more suitable for manufacturing a power transmission chain that is movably fitted into the front insertion part of one link and fixed to the rear insertion part of the other link. .

  In this power transmission chain, 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, the pin is referred to as “first pin” or “pin”, and the other is referred to as the pin that does not contact the pulley (interpiece or strip). "Peace").

  According to the power transmission chain manufacturing method of the present invention, in the pretension applying step, the removable protective members are attached to both ends of each pin to apply pretension, so that the pin end surface is connected to the pulley via the protective member. The contact with the sheave surface can prevent damage to the pin end surface without changing the material and shape of the pulley, thereby improving the durability of the chain.

FIG. 1 is a plan view showing a part of one embodiment of a power transmission chain manufactured by the method of manufacturing a power transmission chain according to the present invention. FIG. 2 is an enlarged side view of the link of the power transmission chain. FIG. 3 is a front view showing a state in which the power transmission chain is attached to the pulley. FIG. 4 is a diagram schematically showing a pretension applying device used in the method of manufacturing a power transmission chain according to the present invention.

  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 manufactured by using the method of manufacturing a power transmission chain according to the present invention. The power transmission chain (1) is provided at predetermined intervals in the chain length direction. A plurality of pins (11) (21) having the inserted front and rear insertion portions (12) (13) and a plurality of pins (11) (21) arranged in the chain width direction so as to be bendable in the length direction (First pin) (14) and an interpiece (second pin) (15). 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 power transmission chain (1) of the present invention, two types of links (11) and (21) are used: a short link (11) and a long link (21). In the short link (11) and the long link (21), the distance between the lines (points in the cross section) where the pin (14) and the interpiece (15) are in contact in the straight region of the chain (1) (FIG. 2). The distance between the point indicated by symbol A and the point indicated by B) = “pitch length” is different.

  As shown in FIG. 2, the front insertion part (12) of the short link (11) (the same applies to the long link (21)) includes a pin movable part (16) and an interpiece to which the pin (14) is movably fitted. It consists of an interpiece fixing part (17) to which (15) is fixed, and the rear insertion part (13) is fitted so that the pin fixing part (18) to which the pin (14) is fixed and the interpiece (15) can be moved. It consists of interpiece movable parts (19) to be matched.

  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).

  When connecting the links (11) (21) arranged in the chain width direction, the front insertion part (12) of one link (11) (21) and the rear insertion part (13) of the other links (11) (21) ) And the links (11) and (21) are overlapped so that the pin (14) is fixed to the rear insertion part (13) of one link (11) (21) and the other link (11) (21) is movably fitted to the front insertion part (12), and the interpiece (15) is movably fitted to the rear insertion part (13) of one link (11) (21) and the other It is fixed to the front insertion part (12) of the links (11) (21). Then, the pin (14) and the interpiece (15) are relatively rolled and brought into contact with each other, whereby the links (11) and (21) can be bent in the length direction (front-rear direction).

  At the boundary between the pin fixing part (18) of the link (11) (21) and the interpiece movable part (19), the upper and lower concave arcuate guide parts (19a) (19b) of the interpiece movable part (19) Are provided with upper and lower convex arc-shaped holding portions (18a) and (18b) for holding the pin (14) fixed to the pin fixing portion (18). 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) Is an involute curve having a base circle of radius Rb and center M in the cross section, 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) (21) moves from the straight region to the curved region of the chain (1) or from the curved region to the straight region, the pin (14) is fixed at the front insertion portion (12). The rolling contact surface (14a) is in contact with the rolling contact surface (15c) of the interpiece (15) while the rolling contact surface (15a) is in contact (including some sliding contact) with respect to the interpiece (15) in the state. In the rear insertion portion (13), the rolling contact surface (15c) is connected to the pin (14) with respect to the pin (14) in a state where the interpiece (15) is fixed in the interpiece movable portion (19). It moves while rolling (including some sliding contact) on the rolling contact surface (14a).

  FIG. 3 shows a power transmission device in which the power transmission chain (1) is attached to a V-type pulley type CVT. In the power transmission device, as shown in FIG. 3, a pulley having a pulley shaft (2e) ( 2) The end face of the pin (14) is the pulley (2) with the end face of the interpiece (15) not in contact with the conical sheave face (2c) (2d) of the fixed sheave (2a) and the movable sheave (2b). ) Contact the conical sheave surfaces (2c) and (2d), and power is transmitted by the frictional force generated by the contact.

  When the movable sheave (2b) of the drive pulley (2) at the position indicated by the solid line in FIG. 3 is moved toward and away from the fixed sheave (2a), the winding diameter of the drive pulley (2) is as shown in FIG. As indicated by the chain line, it is large when approaching and small when separated. In the driven pulley, although not shown, 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 is wound. When the diameter is reduced and the winding diameter of the drive pulley (2) is reduced, the winding diameter of the driven pulley is increased. As a result, a U / D (underdrive) state in which the winding diameter of the drive pulley (2) is the smallest and the winding diameter of the driven pulley is the maximum is obtained based on the state where the gear ratio is 1: 1. In addition, an O / D (overdrive) state in which the winding diameter of the drive pulley (2) is maximum and the winding diameter of the driven pulley is minimum is obtained.

  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, both the contact surfaces of the pin and the interpiece are arcuate surfaces. Compared to the case, vibration can be reduced and noise can be reduced.

  When used in the CVT, the pin (14) and the interpiece (15) are guided by the movable parts (16) and (19) as described above to move in rolling contact with the pulley (2). The 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.

  This power transmission chain (1) has the necessary number of pins (14) and interpieces (15) held vertically on the assembly jig, and then one or several links (11) and (21). Manufactured by pressing 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 (18) and the interpiece fixing part (17). It is set to 0.005 mm to 0.1 mm. Thus, an appropriate tension is applied to the assembled chain (1) in the pre-tensioning process.

  FIG. 4 shows a pretensioning device (31) used in the method of manufacturing a power transmission chain according to the present invention.

  The pretensioning device (31) includes a first pulley (32), a second pulley (33), a rotation drive device (34) for rotating the rotation shaft of the first pulley, and a length direction drive device (36). To adjust the tension acting on the chain (1) by moving the second pulley (33) in the chain length direction so that the distance between the axes of the pulleys (32) and (33) approaches and separates. And a vertical movement table (35).

  Each pulley (32) (33) has a sheave surface (32a) (33a) having the same shape as the sheave surface (2c) (2d) of a continuously variable transmission that is actually used.

  The pretension applying device is a known one, and the power transmission chain manufacturing method according to the present invention includes a removable protective member (37) in the pretension applying step using the pretension applying device (31). Is attached to both ends of the pin (14) to apply pretension.

  The protective member (37) is made of a softer material than the pin (14), and its hardness is set lower than the hardness of the pin (14). Specifically, the pin (14) made of bearing steel is also made of bearing steel, and the heat treatment conditions are different from those of the pin (14). The HRC hardness of the pin (14) is higher than the HRC hardness of the pin (14). Is also made 1-2 smaller.

  The protective member (37) has a cylindrical shape including a peripheral wall (41) and an end wall (42), and the inner peripheral surface (41a) of the peripheral wall (41) is formed along the outer peripheral surface of the end portion of the pin (14). The inner surface (42a) of the end wall (42) is shaped along the end surface of the pin (14). The outer surface (42b) of the end wall (42) has the same shape as the end surface shape of the pin (14). The outer peripheral surface (41b) of the peripheral wall (41) may have the same shape as the outer peripheral surface of the pin (14), or may be a cylindrical surface or a rectangular tube surface.

  The end surface of the pin (14) has an inclination angle of 11 °, corresponding to the conical sheave surfaces (2c) and (2d) of the V-type pulley type CVT having an inclination angle of 11 °. The inner surface (42a) and the outer surface (42b) of the end wall (42) of the protection member (37) have an inclination angle of 11 ° corresponding to the end surface shape of the pin (14). The end surface of the pin (14) is preferably a curved surface. In this case, the inner surface (42a) and the outer surface (42b) of the end wall (42) of the protective member (37) are also curved surfaces.

  At the time of pre-tensioning, the protection member (37) is fitted on both ends of the pin (14), and the pin (14) is connected to the sheave surface (each of the pulleys (32), (33)) via the protection member (37). 32a) and (33a) come into contact, and in this state, a pretension is applied to the power transmission chain (1). Since the hardness of the protective member (37) is set lower than the hardness of the pin (14), in this pretensioning step, no indentation occurs on the end surface of the pin (11), and the end surface of the pin is not damaged. A predetermined pretension load can be applied.

  The amount of pretension is determined by the maximum principal stress value generated in the link (11) (21) (especially the press-fitting part in the pin fixing part (18) and interpiece fixing part (17)). It is set so as to be not less than the elastic limit and not more than the yield point, whereby an appropriate residual compressive stress is applied to the inside of the links (11) and (21). In order to obtain an appropriate residual compressive stress, it is necessary to apply a larger pretension than that applied by the actual machine.In this case, the end surface of the pin (14) may be damaged, but the protective member (37) By using, this damage can be prevented.

  The manufacturing method described above is not limited to the shapes of the link, pin, and interpiece, and can be applied to various power transmission chains that require pre-tensioning.

(1) Power transmission chain
(2) Pulley
(11) Link
(14) Pin (1st pin)
(15) Interpiece (2nd pin)
(32) Pre-tension first pulley
(33) Pre-tension second pulley

Claims (2)

A method of manufacturing a power transmission chain comprising a plurality of links and a plurality of pins connecting them and being wound between two pulleys,
A protective member is provided that includes a step of applying a pretension to the chain by winding an endless chain between the first pulley for applying pretension and the second pulley for applying pretension. Is attached to both ends of each pin to apply pretension, and a method of manufacturing a power transmission chain.   The protective member is made of the same material as the pin, and has a HRC hardness of 1 or more lower than that of the pin by changing heat treatment conditions.

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