JP2008110378A - Method for manufacturing power transmitting chain, and apparatus for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a power transmitting chain where, when pretension is increased, and suitable residual compressive stress is applied to a link, the damage of a pin can be prevented, and to provide an apparatus for manufacturing the same. <P>SOLUTION: The apparatus for manufacturing a power transmitting chain is provided with a pretension applying apparatus 31 comprising: a first pulley 32 for applying pretension and a second pulley 31 for applying pretension around which an endless chain 1 is wound. The relatively confronted sieve faces 32a, 33a in the respective pulleys 32, 33 for applying pretension has recessed shape corresponding to the projecting curved part 14a in the edge face of each pin 14. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method and apparatus for manufacturing a power transmission chain, and more particularly to a method and apparatus for manufacturing a power transmission chain 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. 8, 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). 2. Description of the Related Art A chain-type continuously variable transmission that generates a load and transmits torque by the frictional force of the contact portion is known.

  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.
JP 2006-102784 A

  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. However, since the pin end surface is a convex curved portion, This may cause damage to the pin end face.

  An object of the present invention is to provide a method and an apparatus for manufacturing a power transmission chain that can prevent damage to a pin when increasing a pretension and applying a more appropriate residual compressive stress to a link.

  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 applying a pretension to the chain by winding an endless chain between the first pulley and the second pretensioning pulley, and the opposite sheave surfaces of the pretensioning pulleys are pin end surfaces. A concave shape corresponding to the convex curved portion is provided.

  A power transmission chain manufacturing apparatus according to the present invention is a power transmission chain manufacturing apparatus that is used by being wound between two pulleys, comprising a plurality of links and a plurality of pins connecting them, and comprising an endless chain. A pretensioning device having a first pretensioning pulley and a second pretensioning pulley to be wound is provided, and the facing sheave surfaces of each pretensioning pulley correspond to the convex curved portion of the pin end surface. It is characterized by having a concave shape.

  Conventionally, the pulley used for applying the pretension has a conventional conical sheave surface whose cross-sectional shape is a straight or convex curved surface, whereas the pin end surface is a convex curved portion. In consideration of this, the curved surface is concave. This increases the contact area between the convex curved portion of the pin end surface and the concave curved portion of the pulley, thereby reducing the contact surface pressure acting on the pin and preventing pin damage even when a large pretension is applied. can do. The convex curved portion of the pin end surface may be a spherical surface, formed by crowning, or have various shapes. The concave curved portion of the pulley only needs to be concave (the contact area with the convex curved portion of the pin needs to be larger than the conical surface having a straight section), and the same as the convex curved portion of the pin end surface. There is no need. The radius of curvature R of the concave curved portion of the pulley is preferably 0.8r ≦ R ≦ 5r, where r is the radius of curvature of the convex curved portion of the pin end surface. When R is smaller than 0.8r, it is difficult to secure a contact surface necessary for the pulley, and when R is larger than 5r, the increase in the contact area is small and the damage prevention effect of the pin is small. Become. The radius of curvature R of the concave curved portion of the pulley is more preferably r ≦ R ≦ 2r.

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

  The pretensioning device for performing tensioning can simulate a continuously variable transmission (actual machine) except for the sheave surface shape. For example, the pretensioning device has a conical surface sheave surface. A first pulley comprising a fixed sheave and a movable sheave, and a second pulley comprising a fixed sheave and a movable sheave each having a conical surface, and moving the movable sheave toward and away from the fixed sheave. By doing so, the chain is clamped. 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.

  At the time of applying the pretension, it is preferable that the diameter of at least one of the pulleys is not more than the actual minimum diameter. In continuously variable transmissions, underdrive (hereinafter referred to as “U / D”) has the maximum speed ratio for low-speed driving, and overdrive (hereinafter referred to as “U / D”) for low-speed driving. O / D "))). The stress amplitude acting on the link according to the movement of the pin is larger when turning along a pulley having a smaller winding diameter than when turning along a pulley having a larger winding diameter. Therefore, it is possible to apply a uniform stress over a wide range to the link by including the size of the winding diameter at the time of applying the pretension not more than the minimum winding diameter obtained by the continuously variable transmission, The link can be extended evenly. In this case, the winding diameter at the time of applying the pretension may be changed steplessly or may be constant, and the winding diameter of one of the first pulley for applying pretension and the second pulley for applying pretension. However, the size is set to be smaller than the minimum winding diameter obtained by the continuously variable transmission temporarily or always.

  The magnitude of the pretension is preferably at least twice (2 to 3 times) the maximum tension applied when used in a continuously variable transmission. When the continuously variable transmission is used for an automobile, it may be more than twice (2 to 3 times) the tension when the nominal torque of the car is applied. Thereby, an appropriate residual compressive stress can be applied to the link.

  The manufacturing method and the manufacturing apparatus described above are suitable for manufacturing various power transmission chains, but a plurality of links having front and rear insertion portions through which pins are inserted, a front insertion portion of one link, and 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 the rear insertion portion, and the first pin and the second pin are relatively rolled and contact moved By doing so, the links 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 the rear insertion portion of the other link By manufacturing a power transmission chain that is movably fitted to the other link, and the other is movably fitted to the front insertion portion of one link and fixed to the rear insertion portion of the other link. Is suitable.

  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").

  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.

  When the pin is fixed to the front and rear insertion portion, the pin is fixed to the front and rear insertion portion, for example, by fitting and fixing the inner edge of the insertion portion and the outer peripheral surface of the pin by mechanical press-fitting. It may be a fit or a cold fit. The first pin and the second pin 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. The fitting and fixing is preferably performed at the edges (upper and lower edges) of the portion orthogonal to the length direction of the insertion portion. After this fitting and fixing, a pre-tension is applied in the pre-tension applying step, so that an appropriate residual compressive stress is uniformly and accurately applied to the pin fixing portion (pin press-fit portion) of the link.

  According to the power transmission chain manufacturing method and the manufacturing apparatus of the present invention, the sheave surfaces facing each other of the pretensioning pulleys are conventionally conical surfaces according to the actual machine, for example. By adopting a concave shape corresponding to the convex curved part of the end surface, even if a pretension greater than that applied by the actual machine is applied, damage to the pin end surface can be prevented and chain durability can be improved. Can do.

  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.

  1 and 2 show a part of a power transmission chain manufactured by 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 links (11) having the inserted front and rear insertion portions (12) and (13) and a plurality of pins (first pins) for connecting the links (11) arranged in the chain width direction so as to be bent in the length direction ( 14) and an interpiece (second pin) (15).

  As shown in FIG. 3, in the front insertion part (12), the pin fixing part (12a) to which the pin (14) (shown by a solid line) is fixed and the interpiece (15) (shown by a two-dot chain line) are movable. The inter-piece movable part (12b) can be fitted to the rear insertion part (13). The pin insertion part (13a) and the inter-piece (13 15) It consists of an interpiece fixing part (13b) to which (shown by a solid line) is fixed. When connecting the links (11) arranged in the chain width direction, the front insertion part (12) of one link (11) and the rear insertion part (13) of the other link (11) correspond to each other. The links (11) are overlapped, and the pin (14) is fixed to the front insertion part (12) of one link (11) and movably fitted to the rear insertion part (13) of the other link (11) The interpiece (15) is movably fitted to the front insertion part (12) of one link (11) and fixed to the rear insertion part (13) 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).

  The locus of the contact position between the pin (14) and the interpiece (15) relative to the pin (14) is an involute curve, and in this embodiment, the contact surface (14a) of the pin (14) is The cross section has an involute shape with a base circle of radius Rb and center M, and the 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 contact surface (15a) moves to the contact surface (14a) of the pin (14) while rolling (including some sliding contact) against the pin (14) in the fixed state in the part (12b) In the insertion part (13), the contact surface (14a) rolls against the contact surface (15a) of the interpiece (15) against the interpiece (15) with the pin (14) fixed (slightly sliding contact) The pin movable part (13a) is moved. In FIG. 3, 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). Is the pitch.

  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.

  This power transmission chain (1) is used in the V-type pulley type CVT shown in FIG. 4. At this time, for example, the interpiece (second pin) (15) is replaced with the pin (first pin) (14). Pin (14) with the end face of the interpiece (15) not contacting the fixed sheave (2a) of the pulley (2) and the conical sheave surfaces (2c) (2d) of the movable sheave (2b). ) Comes into contact with the conical sheave surfaces (2c) and (2d) of the pulley (2), and power is transmitted by the frictional force generated by the contact. The end surface shape of the pin (14) that contacts the conical sheave surfaces (2c) and (2d) of the pulley (2) is formed in a convex curved shape. 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 ensured.

  In FIG. 4, 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, as shown in FIG. 5, the winding diameter of the drive pulley (2) is the smallest and the winding diameter of the driven pulley (3) with reference to the state (initial value) where the gear ratio is 1: 1. The U / D state in which the drive pulley (2) is maximum is obtained, and the O / D state in which the drive pulley (3) is minimum is obtained.

  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 (12a) and the interpiece fixing part (13b). It is set to 0.005 mm to 0.1 mm. Thus, a pretension is applied to the assembled chain (1).

  FIG. 6 shows a pretensioning device used in the manufacturing method and manufacturing apparatus according to the present invention.

  The pretensioning device (31) includes a small-diameter pulley (32) whose winding diameter is the minimum winding diameter that can be obtained by a continuously variable transmission, and a maximum winding that can be obtained by a continuously variable transmission. A large-diameter pulley (33) having a large diameter, a pulley shaft moving device (34) that adjusts the tension acting on the chain (1) by moving the pulleys (32) and (33) closer to and away from each other, and a pulley ( 32) and a rotational drive device (35) for rotating (33).

  The sheave surfaces (32a) and (33a) facing each other of the pretension applying pulleys (32) and (33) of the pretension applying device (31) have been conventionally conical, for example, in accordance with the actual machine. On the other hand, as shown in an enlarged view in FIG. 7, the curved surface is a concave curved surface corresponding to the convex curved portion (14a) of the end surface of the pin (14). The radius of curvature R of the sheave surfaces (concave curved portions) (32a) and (33a) of the pulleys (32) and (33) is 0.8r, where r is the radius of curvature of the convex curved portion (14a) of the end surface of the pin (14). ≦ R ≦ 5r.

  The combination of the diameters of the small diameter pulley (32) and the large diameter pulley (33) of the pretensioning device (31) is the same as the U / D state (same as the O / D state), and the pin (14) and the interface The movement of the piece (15) is large, which is a severe condition for the chain (1), and the winding diameter when pre-tensioning is included is not more than the minimum winding diameter that can be obtained with a continuously variable transmission. As a result, residual compressive stress is evenly applied to the link (11), and the durability of the chain (1) is improved.

  The amount of pretension is such that the maximum principal stress value generated inside the link (11) (especially the press-fitted part at the pin fixing part (12a) and the interpiece fixing part (13b)) exceeds the elastic limit of the link (11). It sets so that it may become below a plastic limit, and, thereby, an appropriate residual compressive stress is given inside a link (11). In order to obtain an appropriate residual compressive stress, it is necessary to apply a pretension greater than that applied by the actual machine.In this case, the end surface of the pin (14) may be damaged. By making the shapes of the pulleys (32) and (33) as described above, this damage can be prevented.

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 perspective view of the same. FIG. 3 is an enlarged side view of the link. FIG. 4 is a front view showing a state in which the power transmission chain is attached to the pulley. FIG. 5 is a side view schematically showing how the power transmission chain changes as the continuously variable transmission shifts. FIG. 6 is a diagram schematically showing the pretension applying device. FIG. 7 is an enlarged view of a main part of FIG. FIG. 8 is a perspective view showing a continuously variable transmission.

Explanation of symbols

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

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 step of applying a pretension to the chain by winding an endless chain between the first pretensioning pulley and the second pretensioning pulley, and the sheaves of each pretensioning pulley facing each other A method of manufacturing a power transmission chain, characterized in that the surface has a concave shape corresponding to the convex curved portion of the pin end surface. An apparatus for manufacturing a power transmission chain comprising a plurality of links and a plurality of pins connecting them and being wound between two pulleys.
A pretension applying device having a pretension applying first pulley for winding an endless chain and a pretension applying second pulley is provided, and the sheave surfaces facing each other of the pretension applying pulleys are convex on the pin end surface. An apparatus for manufacturing a power transmission chain, wherein the manufacturing apparatus is a concave shape corresponding to a curved portion.

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