JP2009222104A - Power transmission chain and power transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power transmission chain and a power transmission device capable of attenuating chordal vibration by setting contact between links at a proper magnitude under such an automatic assembling facilitating condition that there are gaps between the links. <P>SOLUTION: By arranging the links 11 so that pitch lengths thereof change from the lowermost stage toward the upper stages in such a state that the links are directly placed on a planar surface, a warp D exists in the chain 1 in such a state that the chain is directly placed on the planar surface. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

As the power transmission chain for continuously variable transmissions, the chain width direction is such that a plurality of links having front and rear insertion portions through which pins are inserted correspond to the front insertion portion of one link and the rear insertion portion of another link. A plurality of first pins and a plurality of second pins arranged before and after connecting the links arranged in parallel, and the first pin and the second pin are relatively in rolling contact and moved, whereby the links are bent in the length direction. What is made possible is known, and Patent Document 1 proposes adjusting the skew amount in the chain width direction in order to cope with misalignment of a continuously variable transmission.
JP-A-2005-321066

  This type of power transmission chain is manufactured by holding a required number of pins vertically and then press-fitting links one by one or several at a time. If there is a gap between adjacent links, there will be no frictional force that acts as a deterrent when chain vibrations occur in the chain, and this tends to cause a problem of increased vibration and noise. The gap may be set to 0, but such a manufacturing method takes time and makes automatic assembly difficult.

  An object of the present invention is to provide a power transmission chain and a power transmission device capable of dampening string vibrations by setting the contact between links to an appropriate size under conditions where there is a gap between the links that can be easily assembled automatically. It is to provide.

  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. In the power transmission chain, the warp exists in a state of being placed directly on a plane.

  The conventional power transmission chain including the one in Patent Document 1 is in a state of being placed on a plane (when placed on a plane in an endless state), the entire surface is in contact with the plane (the amount of warping is 0). Is made). On the other hand, in the power transmission chain according to the present invention, in a state where the plane is directly placed, a part of the chain is in contact with the plane and a part of the chain is floated. At the time of assembly, there is a gap between adjacent links arranged in the chain width direction. Here, the “gap” means a gap at the time of design when the link is not warped. The gap between the links is set by setting the link position when the link is fixed (press-fit) to the pin as a predetermined position.

  In order to cause warpage in a state where the flat surface is placed directly, it is only necessary that adjacent pins are not parallel in at least a part of the endless chain. In addition, in the state before the endless chain, it is made a quadrilateral (for example, trapezoid) that is not a parallelogram (usually a rectangle in the conventional one), and the end faces thereof are butted to be endless. But you can get it.

  When this chain is attached to a continuously variable transmission, tension in the direction of travel is applied to the chain, so that the chain is in a straight state in the direction of travel. An appropriate frictional force is formed between them, and the frictional force suppresses string vibration of the power transmission chain. In this case, the contact state between the links is more flexible (spring state) than that in which the gap is zero at the time of assembly, and rotation unevenness due to the excessively negative gap is less likely to occur. If the warpage is too large, it has an adverse effect on durability and noise reduction. Therefore, it is preferable that the amount of warpage be less than 1.5 mm, with the maximum amount that the floating part forms a flat surface as the “warpage amount”. The lower limit of the warpage amount is not particularly limited, but if it is 0.3 mm or more (preferably 0.5 mm or more), durability and noise reduction can be improved reliably. This effect can be obtained regardless of the misalignment value, friction between the links can be effectively obtained in the entire speed range, and noise can be reduced in the entire speed range.

  The warpage in the plane-placed state can be obtained, for example, by using one or several of the following four configurations.

1. Each link is formed as a single item that is warped, and is arranged so that the warpage is in the same direction in a state of being placed on a plane. To do this, for example, the link may be warped at the time of press molding for forming the front and rear insertion portion, and as a result, the link and pin are exactly the same as the conventional one, Warpage can be obtained in a state where the plane is placed directly.

2. Each link is arranged so that the pitch length changes as it goes from the lowest level to the upper level in a state of being placed directly on the plane. When the pitch length is constant, the chain has a cylindrical shape as a whole, but by changing the pitch length in this way, the chain is displaced from the cylinder, and warpage occurs in a state of being placed directly on a plane.

3. The pitch length of the lowermost link is different from the pitch length of the uppermost link in the state of being placed directly on a plane. In this case, the pitch length of the intermediate link may be the same as the pitch length of the lowermost link, may be the same as the pitch length of the uppermost link, or may be the intermediate pitch length of these. In this way, the number of types of links can be reduced compared to 2 above.

4). The back surface of each pin is tapered in the pin axis direction.

  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.

  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. It is preferable that the pin is fixed to the rear insertion portion of another link, and the pin is fixed to the front and rear insertion portion by, for example, fitting between the inner edge of the insertion portion and the outer peripheral surface of the pin by mechanical press-fitting. Although fixed and fixed, instead of this, shrink fitting or cold fitting may be used. 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 the fitting and fixing, a pretension is applied in the pretension applying step, so that an appropriate residual compressive stress is uniformly and accurately applied to the pin fixing portion (pin press-fitting portion) of the link.

  For example, the first pin and the second pin are formed in a required curved surface so that one of the rolling contact surfaces is a flat surface and the other rolling contact surface is relatively rolling and movable. Moreover, you may make it a rolling contact surface form a required curved surface for the 1st pin and the 2nd pin. In any case, two types of rolling contact surface shapes of each pin (for example, those having a relatively large curvature and those having a relatively small curvature) are formed, so that the locus of the rolling contact movement is different. There may be two types of pin pairs. The locus of the contact position between the first pin and the second pin is, for example, an involute curve.

  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.

  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 above.

  In such a power transmission device, misalignment occurs (the center line in the width direction of the first pulley and the center line in the width direction of the second pulley are shifted in the axial direction of the pulley) as the speed ratio changes. The misalignment is preferably set in a direction in which the warp is corrected in a predetermined region (for example, the entire transmission region). In this way, in a predetermined region, the frictional force between the links arranged in the chain width direction is increased due to misalignment, and the string vibration is more reliably attenuated.

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

  According to the power transmission chain and the power transmission device of the present invention, it is possible to obtain an appropriate frictional force between the links in the tension load state by causing the warp in the state of being placed straight on the plane. String vibration is suppressed. In addition, the contact state between the links is softer than that in which the gap is set to 0 at the time of assembly, and rotation unevenness due to the excessively negative gap is less likely to occur.

  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 the basic structure of a power transmission chain according to the present invention. The power transmission chain (1) is a front-rear insertion portion (12) (13) provided at a predetermined interval 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). The interpiece (15) is shorter than the pin (14), and the pin (14) is wider in the front-rear direction than the interpiece (15). The pin (14) is opposed to the front side in a state of being arranged 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.

  As shown in FIG. 2, the front insertion part (12) of each link (11) includes a pin movable part (16) to which the pin (14) is movably fitted and an interpiece to which the interpiece (15) is fixed. The rear insertion part (13) is composed of a fixed part (17), and the inter-piece movable part (19) in which the pin fixed part (18) to which the pin (14) is fixed and the inter-piece (15) are movably fitted together Consists of.

  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).

  This power transmission chain (1) holds the required number of pins (14) and interpieces (15) vertically on the assembly jig, and then press-fits one or several links (11) one by one. It is manufactured by doing. This press-fitting is performed between the upper and lower edges of the pin (14) and the interpiece (15) and the upper and lower edges of the pin fixing part (18) and the interpiece fixing part (17). It is set to 0.005 mm to 0.1 mm. In this way, tension is applied (pre-tensioned) to the assembled chain (1).

  The power transmission chain is used in the CVT. At this time, as shown in FIG. 7, each cone of the fixed sheave (2a) and the movable sheave (2b) of the pulley (2) having the pulley shaft (2e). The end surface of the pin (14) is in contact with the conical sheave surface (2c) (2d) of the pulley (2) while the end surface of the interpiece (15) is not in contact with the cylindrical sheave surface (2c) (2d). Power is transmitted by frictional force due to 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.

  In the power transmission chain (1), a gap of a predetermined size is set between the links (11) adjacent in the chain width direction. When the clearance is set in this way, the frictional force that attenuates the vibration is reduced for the string vibration of the chain (1) compared to the case where the clearance is 0. To compensate.

  Conventionally, the power transmission chain (1) according to the present invention has a warp of 0 in a state where the plane is directly placed, that is, all the pins (14) and the interpiece (15) are vertical, and the lower end surface of the pin (14). Is formed so as to be in contact with a plane, whereas there is a large number of pins (14) (and interpieces (15) as shown in FIG. )) Is inclined from the vertical, part is in contact with the plane P, and part is in a floating state. In the figure, D is the amount of warp, which is 0.5 to 1.5 mm.

  The warpage D in the state of being placed directly on a plane can be obtained by using one or several of the embodiments schematically shown in FIGS.

  In the embodiment shown in FIG. 4, each link (11) is formed as a single product in a warped state, and is arranged so that the warp is in the same direction (convex upward) in a plane-mounted state. In order to do this, for example, the link (11) may be warped during press molding for forming the front and rear insertion portions (12) and (13). (14) and the interpiece (15) can be used in exactly the same manner as before, and warp can be obtained in a state where they are placed directly on a plane. The amount of warpage of each link (11) may of course be the same, but links (11) having different warpage amounts as a single item may be randomly arranged. Further, the warpage may be gradually changed from the lowest level to the upper level.

  In the embodiment shown in FIG. 5, each link (11) is arranged such that the pitch length changes from P1 to P2 (P1 <P2) as it goes from the lowest level to the upper level in a state of plane placement. When the pitch length is constant, the parallelism between adjacent pins (14) and interpieces (15) is ensured, and the chain (1) has a cylindrical shape as a whole, but the link (11) along the pin axis direction. Since the pitch length of the chain (1) is changed from P1 to P2, the chain (1) is deviated from the cylinder, and warpage occurs in a state where the chain is placed directly on the plane.

  Although not shown in FIG. 5, the pitch length of the intermediate link (11) does not necessarily need to be gradually changed, and the pitch length P1 of the lowermost link (11) and the uppermost link in the state of being placed directly on the plane. If the pitch length P2 of the link (11) is different, the same effect can be obtained. In this case, the pitch length of the intermediate link (11) may be the same as the pitch length P1 of the lowermost link (11), or may be the same as the pitch length P2 of the uppermost link (11). These pitch lengths may be intermediate. In this way, the number of types of links (11) can be reduced compared to that shown in FIG.

  In the embodiment shown in FIG. 6, the back surface of each pin (14) (the surface opposite to the surface (15a) in rolling contact with the interpiece (15)) (14b) is tapered in the pin axis direction. Yes. As a result, the axial directions of the pins (14) are not parallel to each other, and warpage occurs in a state where the plane is directly placed.

  Thus, according to this power transmission chain (1), since there is warp D in the state of being placed directly on the plane, the frictional force between the adjacent links (11) becomes a resistance force in the tension load state and vibrates. On the other hand, while the links (11) are in contact with each other, they are in a soft state (spring state), so there is no excessive contact pressure between the links (11). The wear of the link (11) can be suppressed, and the transmission efficiency of the chain (1) is not significantly reduced.

  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 curve, the rolling contact surfaces of the pin and the interpiece are both circular arc surfaces. Compared to the case, vibration can be reduced and noise can be reduced. And when it is used in CVT, the string vibration is suppressed and the noise can be further reduced due to the presence of warpage in the state of being placed directly on the plane.

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 side view of the link and the pin. FIG. 3 is a diagram schematically showing a state in which the power transmission chain according to the present invention is placed directly on a plane. FIG. 4 is a diagram schematically showing an embodiment for warping in a state of being placed directly on a plane. FIG. 5 is a diagram schematically illustrating another embodiment for warping in a state of being placed directly on a plane. FIG. 6 is a diagram schematically showing still another embodiment for warping in a state of being placed directly on a plane. FIG. 7 is a front view showing a state in which the power transmission chain is attached to the pulley.

Explanation of symbols

(1) Power transmission chain
(2) (3) Pulley
(2c) (2d) Conical sheave surface
(11) Link
(12) Front insertion part
(13) Rear insertion part
(14) Pin (1st pin)
(15) Interpiece (2nd pin)

Claims (6)

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 by the presence of warpage in the state of flat placement.   2. The power transmission chain according to claim 1, wherein each link is formed as a single product that is warped, and is arranged so that the warpage is in the same direction in a state of being placed directly on a plane.   2. The power transmission chain according to claim 1, wherein each link is arranged so that a pitch length is changed from a lowest level to an upper level in a state of being placed directly on a plane.   2. The power transmission chain according to claim 1, wherein the pitch length of the lowermost link and the pitch length of the uppermost link are different from each other in the state of being placed directly on a plane.   2. The power transmission chain according to claim 1, wherein the back surface of the first pin or the second pin is tapered in the pin axis direction.   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 any one of claims 1 to 5.

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