JP4770454B2 - Method for manufacturing power transmission chain for continuously variable transmission - Google Patents

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 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 order to improve the durability of this type of power transmission chain, before making the chain endless in the manufacturing process, tension is applied (pre-tensioned) to the chain in advance, so that an appropriate residual force remains on the link. Applying compressive stress is performed.
Japanese Patent Laid-Open No. 8-31725

  In this type of power transmission chain, the durability of the link is particularly important, and further improvement of the durability is a problem.

  An object of the present invention is to provide a continuously variable transmission capable of improving the life of a chain by giving a more appropriate residual compressive stress to a link and improving its durability by considering the conditions during pretensioning. It is in providing the manufacturing method of the power transmission chain for motors.

  A method for manufacturing a power transmission chain for a continuously variable transmission according to the present invention includes a first pulley comprising a fixed sheave and a movable sheave each having a conical surface sheave surface, and a fixed sheave and a movable sheave each having a conical surface sheave surface. A second pulley comprising: a plurality of links and an endless power transmission chain that is wound between the pulleys and includes a plurality of links and a plurality of pins that connect the links. A method of manufacturing a power transmission chain used in a continuously variable transmission in which a hanger diameter is changed steplessly and a stepless speed change is performed, the step of forming an endless chain by combining a link and a pin, A step of applying a pretension to the chain by winding an endless chain between the first pulley for applying tension and the second pulley for applying pretension. It is characterized in that the winding diameter during grant has been made to include the size of the minimum winding diameter or less under obtained in a continuously variable transmission.

  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 movement of the pin and thus the load on the link is greater when rotating along a pulley with a smaller winding diameter than when rotating along a pulley with a larger winding diameter. Therefore, in the pretensioning step, uniform stress is applied to a link over a wide range by making the winding diameter at the time of pretensioning include a size less than the minimum winding diameter that can be obtained with a continuously variable transmission. The link can be extended without unevenness.

  The winding diameter at the time of applying the pretension may be changed steplessly or may be constant, and the winding diameter of either the first pulley for applying pretension or the second pulley for applying pretension is temporarily In general or always, the size is equal to or smaller than the minimum winding diameter obtained by the continuously variable transmission.

  A pretension applying device for performing pretensioning can simulate a continuously variable transmission (actual machine). For example, the pretension applying device includes a fixed sheave and a movable sheave each having a conical sheave surface. And a second pulley consisting of a fixed sheave and a movable sheave each having a conical surface, and moving the movable sheave closer to and away from the fixed sheave. It shall be clamped. In this case, the position of the movable sheave is adjusted so that the winding diameter includes a size equal to or smaller than the minimum winding diameter obtained by the continuously variable transmission.

  The pretension applying device does not need to simulate a continuously variable transmission (actual machine). For example, the movable sheave of each pulley is fixed, and the pretension applying device has a conical surface sheave surface. A first pulley having a pair of fixed sheaves opposed to each other at a first interval, and a second pulley having a pair of fixed sheaves each having a conical sheave surface opposed to each other at a second interval The pulley may be provided, and tension may be applied to the chain by moving the pulleys closer to or away from each other. In this case, one of the first interval and the second interval is set so that the winding diameter is equal to or smaller than the minimum winding diameter obtained by the continuously variable transmission, and the other winding diameter is set. Is set to be in a U / D or O / D state, for example.

  In the case where the pretension applying device is not a simulation of a continuously variable transmission (actual machine), preferably, the pretension applying device has a winding diameter that is equal to or smaller than a minimum winding diameter obtained by the continuously variable transmission. Equipped with a small-diameter pulley and a large-diameter pulley whose wrapping diameter is about the maximum wrapping diameter that can be obtained with a continuously variable transmission, and applies tension to the chain by moving the pulleys closer to each other. It is said. “The size of the maximum winding diameter” means a diameter corresponding to the state of U / D or O / D, but the diameter of the large pulley is more suitable than the diameter of the small pulley. Since the contribution to the application is small, the maximum winding diameter may be about 0.8 to 1.2, for example.

  When the pretension applying device is a model of a continuously variable transmission (actual machine), the winding diameter can be changed steplessly, and pretension can be applied under conditions close to the conditions of use of the actual machine. Therefore, there is a problem that the configuration of the pretension applying device is complicated and expensive. In a pretensioning device using a fixed-diameter small-diameter pulley and a large-diameter pulley, this problem is solved, and under the same conditions as the U / D and O / D conditions, which are severe (important) conditions for the chain Since the pretension is applied, the residual compressive stress after the pretension can be obtained substantially equivalent to the case where the pretension is applied under conditions close to the use conditions of the actual machine. The diameter of the small-diameter pulley may of course be equal to the minimum winding diameter obtained by the continuously variable transmission, but may be slightly smaller than the minimum winding diameter and set to a more severe condition.

  The pretension is set 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, an appropriate residual compressive stress is applied to the inside of the link, and the fatigue durability performance is improved.

  Further, the pretension is not generated by the pulley clamping force (similar to the actual machine), but the center-to-axis distance between the pretension applying first pulley and the pretension applying second pulley is changed within a predetermined range. It is preferable to generate it. In this case, the change range of the distance between the pulley shaft centers is 0.1% to 15%, preferably 0.1% to 10% of the initial value.

  The above manufacturing method is suitable for manufacturing various types of power transmission chains for continuously variable transmissions, 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 the like. 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 portions of the links, and the first pins and the second pins roll relatively. By making contact movement, the links can be bent in the longitudinal direction, and one of the first pin and the second pin is fixed to the front insertion portion of one link and after the other link. A power transmission chain is manufactured that is movably fitted in the insertion part, and the other is movably fitted in the front insertion part of one link and fixed to the rear insertion part of the other link. More suitable for.

  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").

  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, 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.

  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 method for manufacturing a power transmission chain for a continuously variable transmission of the present invention, the winding diameter at the time of applying the pretension is set to include a size equal to or smaller than the minimum winding diameter obtained by the continuously variable transmission. Therefore, the range in which the pins are in rolling contact with each other is widened, a load is uniformly applied to the link, the elongation of the link is uniform, and the residual compressive stress applied to the link is also uniform and appropriate. Thereby, the elongation of the continuously variable transmission chain due to the pretension can be accurately managed, and the durability of the link is improved. In addition, since the link can be extended without unevenness, an unnecessarily change in the pin position (tilt angle) can be suppressed, and noise accompanying a change in the pin tilt can be reduced.

  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 for continuously variable transmission according to the present invention. The power transmission chain (1) is predetermined in the chain length direction. A plurality of links (11) having front and rear insertion portions (12) and (13) provided at intervals, and a plurality of pins (links) that link the links (11) arranged in the chain width direction so that they can be bent in the length direction ( A first pin (14) and an interpiece (second pin) (15) are provided.

  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), and the pin insertion part (13a) and the inter-piece (13) to which the pin (14) (indicated by a two-dot chain line) can be movably fitted. 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 of the circle.In this embodiment, the contact surface (14a) of the pin (14) is The cross section has an involute shape having a basic circle with a radius Rb and a 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. 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.

  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, 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).

  The manufacturing method of a power transmission chain for a continuously variable transmission according to the present invention is conventionally replaced with a manufacturing method in which a link and a pin are combined to form a belt-like chain, and a pretension is applied to the chain, thereby making it endless. The link (11) and the pin (14) (15) are combined to form the endless chain, and then the pretensioning step is performed. Yes. FIG. 6 shows a pretension applying device.

  The pretensioning device (31) includes a small-diameter pulley (32) having a 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, and 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. Yes. The combination of the diameters of the small-diameter pulley (32) and the large-diameter pulley (33) is the same as the U / D state (same as the O / D state), and the movement of the pin (14) and the interpiece (15) is It is a big and difficult condition for the chain (1). When pretension is applied under these conditions, as shown in FIG. 7, the rolling contact point between the pin (14) and the interpiece (15) moves within the range indicated by the arrow (L) under the same tension, A load is uniformly applied to the hatched portion of the link (11). In this way, the winding diameter at the time of applying the pretension is made to include a size equal to or smaller than the minimum winding diameter obtained by the continuously variable transmission, so that the residual compression stress is evenly applied to the link (11), The durability of the chain (1) is improved.

  The magnitude of the tension is such that the maximum principal stress value generated inside the link (11) (especially the press-fit part at the pin fixing part (12a) and the interpiece fixing part (13b)) is greater than the elastic limit of the link (11) and is plastic. It is set so as to be below the limit, thereby giving an appropriate residual compressive stress inside the link (11) and improving the life of the link (11). The effect of imparting the pre-tension is remarkable. However, the pre-tension applying step can be applied to a chain in which the lengths of the first pin and the second pin are substantially equal and both are in contact with the sheave surface. The present invention can be applied to a chain in which both are movably fitted to the front and rear insertion portions and various other types of power transmission chains.

FIG. 1 is a plan view showing a part of an embodiment of a power transmission chain manufactured by a method for manufacturing a power transmission chain for a continuously variable transmission 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 a view schematically showing a compression stress application state of the link of the power transmission chain manufactured by the manufacturing method of the present invention. FIG. 8 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)
(15) Interpiece (2nd pin)
(32) Pre-tension first pulley
(33) Pre-tension second pulley

Claims (3)

A first pulley composed of a fixed sheave and a movable sheave each having a conical surface sheave surface, a second pulley composed of a fixed sheave and a movable sheave each having a conical surface sheave surface, a plurality of links, and connecting them It has an endless power transmission chain consisting of a plurality of pins and wound between both pulleys, and the winding diameter is changed steplessly as the distance between sheaves of each pulley changes, and stepless speed change is performed. A method of manufacturing a power transmission chain used in a continuously variable transmission,
A step of combining the link and the pin to form an endless chain; a step of winding the endless chain between the first pulley for applying pretension and the second pulley for applying pretension to apply pretension to the chain; A power transmission chain for a continuously variable transmission, characterized in that the winding diameter at the time of pretensioning includes a size equal to or smaller than the minimum winding diameter obtained by the continuously variable transmission. Production method.   2. The continuously variable transmission according to claim 1, wherein the magnitude of the tension is changed by changing a distance between axial centers of the first pulley for pretensioning and the second pulley for pretensioning within a predetermined range. A method of manufacturing a power transmission chain for a machine.   The power transmission chain connects links arranged in the chain width direction so that multiple links with front and rear insertion parts through which pins are inserted correspond to the front insertion part of one link and the rear insertion part of another link A plurality of first pins and a plurality of second pins arranged before and after, and the first pin and the second pin are in rolling contact with each other, whereby the links can be bent in the length direction; 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. The method of manufacturing a power transmission chain for a continuously variable transmission according to claim 1 or 2, wherein the power transmission chain is movably fitted to the rear and fixed to a rear insertion portion of another link.

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