JP2007032814A - Power transmitting chain and power transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power transmitting chain which relieves stress concentration produced in a link and keeps the elongation of a chain within an appropriate value, and a power transmission device. <P>SOLUTION: A power transmitting chain 1 is equipped with a plurality of links 11, a plurality of pins 14 and a plurality of interpieces 15. Each link is formed by press molding. In the link 11L on the left side, a parting drip D produced in the press molding is positioned on the left side. In the link 11R on the right side, the parting drip D produced in the press molding is positioned on the right side. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a power transmission chain, and more particularly to a power transmission chain suitable for a continuously variable transmission (CVT) of an automobile and a power transmission device using the same.

  As a continuously variable transmission for an automobile, as shown in FIG. 7, 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). It is known that a load is generated and torque is transmitted by the frictional force of the contact portion.

As a power transmission chain, Patent Document 1 (Japanese Patent Laid-Open No. 8-31725) discloses 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. A plurality of first pins and a plurality of second pins that connect the links arranged in the chain width direction so that they can be bent in the length direction, and are fixed to the front insertion portion of one link and The first pin movably fitted in the rear insertion portion of the link and the second pin movably fitted in the front insertion portion of one link and fixed to the rear insertion portion of the other link are relatively rolled. Proposals have been made in which the links can be bent in the longitudinal direction by moving in contact.
Japanese Patent Laid-Open No. 8-31725

  In this type of power transmission chain, the durability of the link is particularly important. In addition, the force that the link receives varies depending on the position of the link, and the outermost link is susceptible to a large force due to the deformation of the pin in the axial direction, which is disadvantageous in terms of durability. .

  An object of the present invention is to provide a power transmission chain and a power transmission device in which the outermost link is easily subjected to a large force and the durability of the outer link is improved to improve the life of the chain.

  The power transmission chain according to the present invention includes 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 arranged before and after connecting each other are provided, and the first pin and the second pin are relatively rolled and brought into contact with each other, whereby the links can be bent in the length direction. The power transmission chain is characterized in that at least the outermost link in the width direction has rounded corners of the outer peripheral edge in the width direction of the front-rear insertion portion.

  One of the first pin and the second pin may be press-fitted and fixed to the front and rear insertion portion of the link, and both may not be fixed (movably fitted). Further, the first pin and the second pin may have different cross-sectional shapes or the same shape. Furthermore, the first pin and the second pin may be the same length, both may be in contact with the sheave surface, and may be of different lengths so that only the longer one is in contact with the sheave surface. Also good. Moreover, as for a link, the front-and-rear insertion part may be an independent through-hole (link with a pillar), respectively, and the front-rear insertion part may be a single through-hole (link without a pillar).

  Each link is manufactured by press molding. In press molding, for example, a lower die (die) is applied to one surface of a plate material, and an upper die (punch) corresponding to the lower die is applied to the other surface of the plate material, and then hit with a striker from the upper die side. This is performed by performing a predetermined punching process.

  In order to round the corners of the outer peripheral edge of the link in the width direction, it is possible to perform post-processing such as chamfering on the peripheral edge after press molding. It is preferable to do the following. That is, when the link is press-molded, two types of links are manufactured in which the outer contour shape and the front-rear insertion portion shape are the same and the front and back sides are reversed. As a result, when the link is attached to the chain, the link has a dropout on the front side (the front side is the front side of the press) and the link has a dropout on the other side (the front side is on the back side of the press) Are formed). Therefore, when assembling the chain, it is possible to use it as a part with rounded corners by assembling so that the dropout comes outside in the width direction. The link that causes the dropout to be outside in the width direction may be only the outermost link in the width direction. For links of about 2 to 3 rows including the outermost side in the width direction, the dropout comes to the outside in the width direction. You may do it. More preferably, the number of two types of links whose front and back sides are reversed at the time of press molding is the same, and these links are arranged symmetrically. In this way, it is possible to obtain a chain simply by taking two molds (or an even number of four or more) and forming the same number of two types of links. There is no need to increase labor. For example, when there are 8 rows and 9 rows of links in the axial direction of the pins, the left and right sides of the 8 rows are symmetrical and the left and right sides of the 9 rows are 4 rows each. Is symmetrical, and the central portion may be only one of the types of links, or two types of links may be alternately arranged in the chain length direction.

  Since links that are susceptible to damage are at or near the outermost side in the width direction of the chain, it is not necessary to align the slipping direction of the link near the center in the width direction of the chain with the outer side in the width direction. Absent.

  At least one of the first pin and the second pin comes into contact with the pulley and transmits 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 ( The other pin is referred to as a “pin” (hereinafter referred to as an “interpiece”), and the other pin is referred to as an interpiece or strip (hereinafter referred to as “interpiece”).

  For example, the first pin and the second pin are formed in a required curved surface so that either one of the contact surfaces is a flat surface and the other contact surface can be relatively rolled and moved. Moreover, you may make it each contact surface form a required curved surface for the 1st pin and the 2nd pin. In any case, the contact surface shape of each pin is formed in two types (for example, one having a relatively large curvature and one having a relatively small curvature), so that the pins having different trajectories of rolling contact movement are formed. There may be two types of sets. The locus of the contact position between the first pin and the second pin is, for example, a circle involute.

  In this specification, one end side in the length direction of the link is front and the other end side is rear, but this front and rear are for convenience, and the length direction of the link always coincides with the front and rear direction. It doesn't mean that.

  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. 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. This 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. In this way, in the pin-fixed chain by fitting, the stress of the fixing portion becomes high, and thus the durability improvement effect due to rounding of the corners of the peripheral portion becomes particularly remarkable.

  This power transmission chain is manufactured, for example, by holding a necessary number of pins and interpieces vertically on a table and then press-fitting links one by one or several at a time. Then, at the time of link press-fitting, each link is arranged so that the portion with rounded corners faces a predetermined direction by press-fitting in consideration of the portion with rounded corners (the side where the press comes off). be able to. When manufacturing the link of this power transmission chain, even one (for example, two) links can be formed by one press molding, and half (one) of the even number of links can be formed. The mold is assumed to be the other half (the other one) with the mold turned upside down.

  In the above power transmission chain, one of the pins (interpiece) is shorter than the other pin (pin), the end surface of the longer pin contacts the conical sheave surface of the pulley of the continuously variable transmission, It is preferable that power is transmitted by the frictional force due to this contact. Each pulley includes a fixed sheave having a conical sheave surface and a movable sheave having a conical sheave surface facing the sheave surface of the fixed sheave. The chain is sandwiched between the sheave surfaces of both sheaves, and the movable sheave. Is moved by a hydraulic actuator, the distance between sheave surfaces of the continuously variable transmission, that is, the wrapping radius of the chain is changed, and a continuously variable transmission can be performed with a smooth movement.

  The power transmission device according to the present invention includes a first pulley having a conical sheave surface, a second pulley having a conical sheave surface, and power transmission spanned between the first and second pulleys. And a power transmission chain as described in any of the above.

  This power transmission device is suitable for use as a continuously variable transmission of an automobile.

  According to the power transmission chain and the power transmission device of the present invention, at least the outermost link in the width direction is rounded at the corners of the outer peripheral edge in the width direction of the front and rear insertion portions, so that the pin is in the axial direction. The durability of the outermost link that receives a large force by deformation is improved, and the life of the chain is improved.

  In addition, each link is formed by press molding, and the dropout that occurs in press molding is used as a part with rounded corners, so that the profile shape of the link is not changed and other performance is deteriorated. And durability can be 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.

  FIGS. 1 and 2 show a part of a power transmission chain according to the present invention. The power transmission chain (1) has front and rear insertion parts (12) (13) provided at predetermined intervals in the chain length direction. ) And a plurality of pins (first pin) (14) and an interpiece (second pin) for connecting the links (11) arranged in the chain width direction so as to be bendable in the length direction. (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), 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.

  Each link (11) is manufactured by press molding. In press molding, a lower die (die) is applied to one surface of a plate material, and an upper die (punch) corresponding to the lower die is applied to the other surface of the plate material, and is hit with a striker from the upper die side. This is done by punching. When such press molding is performed, slippage occurs on the press front side of the link (11), and the corners of the front peripheral edge of the front and rear insertion portions (12) and (13) are rounded, and the link (11) Burrs are generated on the back side of the press, and the corners of the peripheral portions on the back side of the front and rear insertion portions (12) and (13) are relatively sharp. Barrel treatment is performed after press molding, and the surface is polished, but the corner on the front side of the link (11) is relatively round and the corner on the back side of the press is kept relatively sharp.

  In the press molding of this link, a mold capable of taking two sheets is used, and two types of links (11L) and (11R) as shown in FIG. 5 are manufactured by one press operation. These two types of links (11L) and (11R) are simply reversed in their front and back, and the outer contour shape and the front and rear insertion portion shape are the same. As a result, in the links (11L) and (11R), a link (11L) having a left side and a link (11R) having a right side (11R) are formed. When assembling the chain, so that the slipping out comes to the outside in the width direction, that is, the one with the slipping out on the left side (11L) is used for the left indicated by L in FIGS. 11R) is arranged for the right side indicated by R in FIGS.

  Thus, the press direction is taken into consideration in the left link L (11) and the right link R (11), so that at least the outermost link (11) in the width direction has its front and rear insertion portions (12) ( The corners of the outer peripheral edge in the width direction of the outer peripheral edge in the width direction and the inner peripheral edge in 13) are rounded.

  According to this power transmission chain, when both ends of the pin (14) come into contact with the pulley and receive a frictional force, the pin (14) is deformed to form a bow in the axial direction. When using the left and right links (11L) and (11R) with the direction of slipping out as described above, as shown in FIG. 4 (a), the left and right links against the axial bending of the pin (14) In any of the links (11L) and (11R), the peripheral portion D with rounded corners comes into strong contact with the pin (14), and the sharp peripheral portion S is damaged due to strong contact with the pin (14). Can be prevented. On the other hand, as shown in FIG. 4 (b), in the case where all the slips are on the right side, for example, the left link (11L) is rounded against the axial bending of the pin (14). It is the same that the peripheral edge D is in strong contact with the pin (14), but in the right link (11L), the sharp peripheral edge S is in strong contact with the pin (14) and the right link (11L) is The burden becomes relatively large. Thus, in the case of FIG. 4 (a), durability is improved only by taking two sheets, although the front and back are reversed at the time of press molding, and defining the direction at the time of assembly.

  In the above embodiment, the front insertion portion (12) and the rear insertion portion (13) are independent through holes, but the through holes for obtaining these insertion portions (12) (13). Although not shown in the figure, in order to relieve stress concentration at the hole edge, the front and rear insertion parts (12) and (13) are communicated with each other by a communication part so that the entire front and rear is formed as one through hole. Good.

  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.

  This power transmission chain (1) is used in the CVT shown in FIG. 6. At this time, for example, the interpiece (second pin) (15) is made shorter than the pin (first pin) (14). The end surface of the pin (14) is not in contact with the conical sheave surfaces (2c) and (2d) of the fixed sheave (2a) and the movable sheave (2b) of the pulley (2). Contact is made with the conical sheave surfaces (2c) and (2d) of the pulley (2), and power is transmitted by the frictional force caused 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.

  The configuration of the links (11), (11R), and (11L) 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 the first pin and the second pin are movably fitted to the front and rear insertion portion and various other types of power transmission chains.

FIG. 1 is a plan view showing a part of one embodiment of 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 diagram schematically showing the force acting on the outermost link. FIG. 5 is a diagram showing a state at the time of press molding of two types of links used in the power transmission chain according to the present invention. FIG. 6 is a front view showing a state in which the power transmission chain is attached to the pulley. FIG. 7 is a perspective view showing an example of a continuously variable transmission in which the power transmission chain according to the present invention is used.

Explanation of symbols

(1) Power transmission chain
(2) (3) Pulley
(2a) (3a) Fixed sheave
(2b) (3b) Movable sheave
(2c) (2d) Conical sheave surface
(11) Link
(11L) Left link
(11R) Right link
(12) Front insertion part
(13) Rear insertion part
(14) Pin (1st pin)
(15) Interpiece (2nd pin)
D Draft (periphery with rounded corners)

Claims (5)

A plurality of links having front and rear insertion portions through which pins are inserted, and a plurality of links arranged before and after connecting links 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. In the power transmission chain provided with the first pin and the plurality of second pins, the first pin and the second pin are in rolling contact with each other, whereby the links can be bent in the length direction.
A power transmission chain characterized in that at least the outermost link in the width direction has rounded corners of the outer peripheral edge in the width direction of the front and rear insertion portion.   The power transmission chain according to claim 1, wherein each link is formed by press molding, and a dropout generated in the press molding is used as a portion with rounded corners.   There are two types of links that have the same outer contour shape and front / rear insertion part shape, and the front and back sides during press molding are reversed, and these links are arranged symmetrically with the detachment being outside in the width direction. The power transmission chain according to claim 2.   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 power transmission chain according to any one of claims 1 to 3, wherein the power transmission chain is movably fitted to the rear and fixed to a rear insertion portion of another link.   A power transmission chain comprising: a first pulley having a conical surface sheave surface; a second pulley having a conical surface sheave surface; and a power transmission chain spanned between the first and second pulleys. A power transmission device according to claim 1.

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