JP2009103152A - Manufacturing method for power transmission chain - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for a power transmission chain capable of giving proper pretension by being used as a continuously variable transmission of a vehicle using a device having a more simple constitution than a pretension giving device having a constitution similar to an actual machine. <P>SOLUTION: A pretension giving step comprises a normal direction stress giving step of increasing an interaxial distance by rotating pulleys 32, 33 in a normal direction in the state that a pressing roller 36 is spaced; a normal direction reverse bending step of pressing an outer periphery of the chain 1 by the pressing roller 36 in the state that the pulleys 32, 33 are rotated in a normal direction; a reverse direction stress giving step of rotating the pulleys 32, 33 in a reverse direction after leaving the pressing roller 36; and a reverse direction reverse bending step of pressing an outer periphery of the chain 1 by the pressing roller 36 in the state that the pulleys 32, 33 are rotated in a reverse direction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a power transmission chain manufacturing method, and more particularly to a manufacturing method used when 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. 6, a drive pulley (2) provided on the engine side having a fixed sheave (2a) and a movable sheave (2b), a fixed sheave (3b) and a movable sheave (3a) and a driven pulley (3) provided on the drive wheel side and an endless power transmission chain (1) spanned between them, and a movable sheave (2b) (3a) by a hydraulic actuator The chain (1) is clamped with hydraulic pressure by moving it toward and away from the fixed sheave (2a) (3b), and this clamping force makes contact between the pulley (2) (3) and the chain (1). 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, a plurality of links having front and rear insertion portions through which pins are inserted, and links arranged in the chain width direction so that a front insertion portion of one link and a rear insertion portion of another link correspond to each other. A plurality of first pins and a plurality of second pins that are flexibly connected in the longitudinal direction, and are fixed to a front insertion portion of one link and movably fitted to a rear insertion portion of another link Bending in the longitudinal direction of the links due to the relative rolling movement of the second pin fixedly attached to the rear insertion part of the other link and movably fitted in the front insertion part of one pin and one link Patent Document 1 discloses a manufacturing method in which a link and a pin are combined to form an endless chain, and an endless chain is wound between a pair of pulleys. Multiply Those and a step of applying a pretension to over emissions have been proposed.
JP 2007-167931 A

  When applying the pretension, it is preferable that the conditions are stricter than those used in an actual continuously variable transmission. According to the manufacturing method of Patent Document 1, the winding diameter at the time of applying the pretension is a continuously variable transmission. This condition is obtained by including a size equal to or less than the obtained winding diameter, and as a result, the range in which the pins come into rolling contact with each other is widened, and the load applied to the link is made appropriate. be able to.

  However, since the rotation direction is only the forward direction (the forward direction of the vehicle) in Patent Document 1, it covers the use conditions for a continuously variable transmission of a vehicle that is also used in reverse rotation. It was not a thing. Further, under actual use conditions, the chain may bend backward (because the link bends in the direction opposite to the direction along the pulley) due to reverse load of torque, but this is not taken into consideration. In addition, in order to use a pretension applying device having a configuration similar to an actual continuously variable transmission (actual device) and to make it a severe condition, the configuration of the device becomes complicated and the cost increases. There is.

  An object of the present invention is to use a device having a simpler configuration than a pretension applying device having a configuration similar to that of an actual machine, and to apply a more appropriate pretension when used as a continuously variable transmission of a vehicle. It is to provide a method for manufacturing a power transmission chain.

  A power transmission chain manufacturing method according to the present invention is a method of manufacturing a power transmission chain comprising a plurality of links and a plurality of pins connecting them, and wound around a pair of pulleys of a continuously variable transmission, The pretensioning step includes a step of forming an endless chain by combining a link and a pin, and a step of applying a pretension to the endless chain. Is used and a pretensioning device having a pair of pulleys that can be rotated in the forward and reverse directions and a pressing roller that can press the outer periphery of the chain is used. Forward-direction stressing process that increases the distance between shaft centers by rotating in the direction, and forward direction that presses the outer periphery of the chain with the pressure roller while rotating the pulley in the forward direction A reverse bending step, a reverse stress applying step of rotating the pulley in the reverse direction after separating the pressing roller, and a reverse reverse bending step of pressing the outer periphery of the chain by the pressing roller while rotating the pulley in the reverse direction; It is characterized by comprising.

  The pretension applying device includes, for example, a pair of pulleys around which an endless chain can be wound, the distance between the shaft centers being changeable, pulley driving means for rotating the pulleys in the forward and reverse directions, and a predetermined tension on the chain. A pulley moving means for changing the distance between the shaft centers so as to be applied; a pressing roller disposed in the middle of the pair of pulleys and movable in a direction perpendicular to a line connecting between the shaft centers of the pulleys; A pressing roller driving unit that rotates the pressing roller and a pressing roller moving unit that moves the pressing roller so as to press a predetermined portion of the outer periphery of the chain inward in the radial direction of the chain are provided.

  The pulley diameter is not particularly limited, and the pair of pulleys may have the same or different diameters. Preferably, the pair of pulleys have the same diameter, and the size thereof is the same as or smaller than the minimum winding diameter obtained by the 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.

  In the conventional pretensioning, paying attention to the mode of the continuously variable transmission, it is assumed that a load equal to or greater than the maximum tension of the use conditions is applied with the minimum winding radius and the forward rotation. However, the power transmission chain is also used in reverse rotation in an actual vehicle, and a reverse bend in which the link bends in a direction opposite to the bend along the pulley may occur. Is expected to decline. Therefore, in the pretensioning step, by applying tension not only in the normal bending condition during forward rotation but also in reverse bending during forward rotation, normal bending in reverse rotation, and reverse bending conditions in reverse rotation. Stress is applied to the link over a wide range (stricter conditions in all respects than actually used conditions), the life can be stabilized, and the durability can be improved. Further, the pretension applying device can have a simple structure as compared with the actual machine, and can apply pretension in a short time.

  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. The pretension can be generated by changing the distance between the pulley shaft centers within a predetermined range, and the range of change of the pulley shaft distance is 0.1% to 15% of the initial value, preferably 0. The range is from 1% to 10%.

  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 of the present invention, tension is applied in the reverse bending at the time of forward rotation, the normal bending of the reverse rotation, and the reverse bending condition of the reverse rotation, which has not been considered in the prior art. As a result, it can be used as a continuously variable transmission of a vehicle, so that an appropriate pretension can be applied, the life of the chain is stabilized, and durability is improved.

  Embodiments of the present invention will be described below with reference to the drawings. In the following description, the top and bottom refer to the top and bottom of FIG.

  FIG. 1 shows a part of a power transmission chain manufactured by the method according to the present invention. The power transmission chain (1) includes front and rear insertion portions (12) provided at predetermined intervals in the chain length direction. A plurality of links (11) having (13) and a plurality of pins (first pins) (14) and interpieces (second) for connecting the links (11) arranged in the chain width direction so as to be bendable in the length direction 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 chain (1), three link rows composed of a plurality of links having the same phase in the width direction are arranged in the traveling direction (front-rear direction) to form one link unit, and the link unit composed of the three rows of link rows is the traveling direction. Are connected to each other. In this embodiment, one link unit includes a link row having nine links and two link rows having eight links.

  As shown in FIG. 2, the front insertion part (12) of the link (11) has a pin movable part (16) to which the pin (14) is movably fitted and an interpiece fixing to which the interpiece (15) is fixed. The rear insertion part (13) consists of a pin fixing part (18) to which the pin (14) is fixed and an interpiece movable part (19) to which the interpiece (15) is movably fitted. Become.

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

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

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

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

  The locus of the contact position between the pin (14) and the interpiece (15) with respect to the pin (14) is an involute of the circle, and in this embodiment, the rolling contact surface (14a) of the pin (14) However, the cross section has an involute shape having a basic circle with a radius Rb and a center M, and the rolling contact surface (15c) of the interpiece (15) is a flat surface (the cross-sectional shape is a straight line). As a result, when each link (11) moves from the straight portion of the chain (1) to the curved portion or from the curved portion to the straight portion, the pin (14) is fixed in the front insertion portion (12). The rolling contact surface (14a) of the piece (15) moves in the pin movable part (16) while being in rolling contact (including some sliding contact) with the rolling contact surface (15c) of the interpiece (15). In the rear insertion part (13), the rolling contact surface (15c) of the interpiece (15) is in contact with the pin (14) in contact with the pin (14) fixed in the interpiece movable part (19). It moves with rolling contact (including some sliding contact) on the surface (14a).

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

  The power transmission chain described above is used in the CVT shown in FIG. 6. At this time, as shown in FIG. 5, the fixed sheave (2a) and the movable sheave (2) of the pulley (2) having the pulley shaft (2e). The end surface of the pin (14) is the conical sheave surface (2c) (2d) of the pulley (2) with the end surface of the interpiece (15) not in contact with each conical sheave surface (2c) (2d) of 2b). Power is transmitted by the frictional force generated by this contact. As described above, the pin (14) and the interpiece (15) are guided by the movable parts (16) and (19) to move in rolling contact with each other, so that the sheave surfaces (2c) (2d) of the pulley (2) On the other hand, the pin (14) hardly rotates, the friction loss is reduced, and a high power transmission rate is secured. When the movable sheave (2b) of the drive pulley (2) at the position indicated by the solid line is moved closer to or away from the fixed sheave (2a), the winding diameter of the chain (1) is indicated by a chain line in the figure. As shown, it is large when approaching and small when separating. Although not shown in the drawing of the driven pulley (3), 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 (2) 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, with reference to the state (initial value) where the gear ratio is 1: 1, U / D has the minimum winding diameter of the drive pulley (2) and the maximum winding diameter of the driven pulley (3). A state is obtained, and an O / D state in which the winding diameter of the drive pulley (2) is maximum and the winding diameter of the driven pulley (3) is minimum is obtained.

  To manufacture this power transmission chain (1), the necessary number of pins (14) and interpieces (15) are held vertically on a table, and then one or several links (11) are assembled. Then, the link (11) and the pins (14) and (15) are combined to form an endless chain, and then a pretension is applied to the assembled chain (1).

  The 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). 0.005 mm to 0.1 mm.

  A pretension applying device used in the step of applying pretension is shown in FIGS.

  The pretensioning device (31) includes a drive pulley (32) and a driven pulley (33) around which an endless chain (1) can be wound and a shaft (32a) of the drive pulley (32). Pulley driving means (34) for rotating the shaft in the forward and reverse directions, and the shaft (32a) of the driving pulley (32) and the shaft of the driven pulley (33) so that a predetermined tension is applied to the chain (1) ( 33a) is arranged between the pulley moving means (35) for changing the distance between the shaft centers and the driving pulley (32) and the driven pulley (33) and connects between the shaft centers of the pulleys (32) and (33). A pressing roller (36) movable in a direction perpendicular to the line, a pressing roller driving means (37) for rotating the shaft (36a) of the pressing roller (36), and a predetermined position on the outer periphery of the chain (1). Pressure roller moving means (not shown) for moving the pressure roller (36) so as to press inward in the chain radial direction is provided.

  The diameters of the driving pulley (32) and the driven pulley (33) are the same as the winding diameter of the drive pulley in the U / D state (same as the winding diameter of the driven pulley in the O / D state), and the pin (14) And the movement of the interpiece (15) is large, which is a severe condition for the chain (1).

  The pre-tension applying step is performed using the pre-tension applying device (31). As shown in FIG. 3 (a), in the state where the pressing roller (36) is separated from the chain (1), the pulley ( 32) (33) is rotated in the forward direction (clockwise) and the distance between the axes is increased to apply the stress under normal bending conditions, and the pulley (32) (33) is moved forward. As shown in FIG. 3 (b), the forward reverse bending step of reversely bending the link (11) by pressing the outer periphery of the chain (1) by the pressing roller (36) as shown in FIG. After separating (36), rotate the pulleys (32) and (33) in the opposite direction (the rotation direction of the pulleys (32) and (33) is counterclockwise in the state of Fig. 3 (a)) under normal bending conditions A reverse stress applying step for applying stress, and the outer periphery of the chain (1) is pressed by the pressing roller (36) while the pulleys (32) and (33) are rotated in the reverse direction (see FIG. 3B). And a reverse reverse bending step in which the rotation direction of the pulleys (32) and (33) is counterclockwise).

  According to the pretensioning step, not only the forward stress applying step but also the forward reverse bending step, the reverse stress applying step, and the reverse reverse bending step are all assumed by applying the pretension. Under these conditions, the rolling contact point between the pin (14) and the interpiece (15) moves, and a load is uniformly applied to the link (11). 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 to be below the limit. As a result, stress can be applied over conditions that are severer than those actually used, appropriate residual compressive stress is applied to the inside of the link (11), and the life of the link (11) is stabilized. The durability of the chain (1) is improved.

  The above pretensioning step has a remarkable effect of improving durability in the press-fit type chain (1) shown in FIGS. 1 and 2, but the lengths of the first pin and the second pin are substantially equal. It can be applied to chains that both contact the sheave surface, and is also applicable to chains and other various types of power transmission chains in which both the first and second pins are movably fitted to the front and rear insertion parts. Is possible.

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. FIG. 3 is a side view schematically showing the pretension applying device. FIG. 4 is a plan view with the same part cut away. FIG. 5 is a front view showing a state in which the power transmission chain is attached to the pulley. FIG. 6 is a perspective view showing a continuously variable transmission.

Explanation of symbols

(1) Power transmission chain
(2) (3) Pulley
(2a) (3b) Fixed sheave
(2b) (3a) Movable sheave
(2c) (2d) Conical sheave surface
(11) Link
(12) Front insertion part
(13) Rear insertion part
(14) Pin (1st pin)
(15) Interpiece (2nd pin)
(32) Drive pulley
(33) Driven pulley
(36) Press roller

Claims (1)

A method of manufacturing a power transmission chain comprising a plurality of links and a plurality of pins connecting them and wound between a pair of pulleys of a continuously variable transmission, and forming an endless chain by combining links and pins And a step of applying pretension to the endless chain,
The pretensioning step includes a pair of pulleys that can change the distance between the shaft centers, can be wound around an endless chain, and can rotate in the forward and reverse directions, and a pressure roller that can press the outer periphery of the chain. Using the applying device, the forward stress applying step of increasing the distance between the axial centers by rotating the pulley in the forward direction with the pressing roller spaced apart, and the chain of the chain by the pressing roller while rotating the pulley in the forward direction. A forward reverse bending step of pressing the outer periphery, a reverse stress applying step of rotating the pulley in the reverse direction after separating the press roller, and pressing the outer periphery of the chain by the pressing roller while rotating the pulley in the reverse direction A method for manufacturing a power transmission chain, comprising a reverse reverse bending step.

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