JP2008223956A - Power transmission belt and belt type continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a relative speed difference between an element and a laminated band in the inlet of a small diameter pulley without lowering the shaping accuracy of a locking edge and the durability of the element. <P>SOLUTION: A saddle face 36 of each element 26 includes a retracted face 36a which is retracted to the inside of the other portion in a band laminating direction. An endless band 44a on the most inner periphery side out of endless bands 44 laminated as the laminated band 24 is set to be the narrowest. This reduces a distance between the endless band 44a on the most inner periphery side and the locking edge 35 and sufficiently secures the width of the locking edge 35. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a power transmission belt and a belt-type continuously variable transmission, and in particular, a laminated band in which a plurality of endless bands are laminated in a pulley radial direction, and the laminated bands are arranged and supported along the circumferential direction. The present invention relates to a power transmission belt including a plurality of elements and wound around a drive pulley and a driven pulley, and a belt-type continuously variable transmission.

  The related art of this type of power transmission belt is disclosed in Patent Document 1 below. In Patent Document 1, the saddle surface of the element that is in contact with the inner peripheral surface of the laminated band and the locking edge that extends in the width direction of the element are positioned at substantially the same level in the height direction of the element. Is set to almost zero. When the rocking edge is offset with respect to the saddle surface, at the small-diameter pulley inlet with the smaller belt engagement diameter of the driving pulley and the driven pulley, the element bitten by the small-diameter pulley is caused by the relative speed difference with the laminated band. Colliding with subsequent elements due to backward tilting. In Patent Document 1, by setting the offset amount of the rocking edge to be almost zero, the relative speed difference between the element and the laminated band is reduced at the small-diameter pulley inlet, and the backward tilt pitching at the small-diameter pulley inlet is suppressed (with the subsequent element). To mitigate collisions).

  In addition, a power transmission belt disclosed in Patent Document 2 below is disclosed.

JP 2000-65153 A JP-A 61-160645

  In Patent Document 1, the distance between the saddle surface of the element and the locking edge (the offset amount of the locking edge) is uniformly set to almost zero in the width direction of the element. However, in that case, it becomes difficult to mold the locking edge, for example, the locking edge is rounded, and the molding accuracy of the locking edge is lowered. For this reason, the width of the locking edge becomes narrow, and the compressive load acting between the elements is handled only by the locking edge having a narrow width. As a result, the durability of the element decreases.

  The present invention provides a power transmission belt and a belt type belt that can reduce the relative speed difference between the element and the laminated band at the small-diameter pulley inlet without lowering the molding accuracy of the locking edge or lowering the durability of the element. An object is to provide a step transmission.

  The power transmission belt and belt type continuously variable transmission according to the present invention employ the following means in order to achieve the above-described object.

  A power transmission belt according to the present invention is a power transmission belt that is wound around a drive pulley and a driven pulley and is driven to transmit the rotation of the drive pulley to the driven pulley. And a plurality of elements arranged and supported on the laminated band along the circumferential direction, each of which is in contact with the driving pulley and the driven pulley as the driving pulley rotates. Each element is formed with a locking edge facing the element adjacent to one side in the belt driving direction, and each element has a rocking edge of the element adjacent to the other side in the belt driving direction as a fulcrum Each element is formed with a saddle surface that contacts the inner peripheral surface of the laminated band. Is formed retraction surface recessed to the layer direction inside, out of the stacked endless bands as laminated bands, the width of the endless band is summarized in that the narrowest in the innermost.

  In the present invention, since the distance between the retracting surface that contacts the inner peripheral surface of the laminated band and the locking edge can be shortened, the driving pulley and the driven pulley are engaged with the smaller pulley having the smaller belt engagement diameter. The relative speed difference between the retracting surface of the element and the laminated band can be reduced. Further, in the portion other than the retracting surface on the saddle surface, the distance from the locking edge can be secured to such an extent that the locking edge is not rounded, and the width of the locking edge can be sufficiently secured. Therefore, it is possible to prevent a reduction in molding accuracy of the locking edge and to handle a compressive load acting between the elements with a wide locking edge. Therefore, according to the present invention, the relative speed difference between the element and the laminated band can be reduced at the small-diameter pulley inlet without lowering the molding accuracy of the locking edge or lowering the durability of the element.

  In one aspect of the present invention, it is preferable that a distance between the endless band located on the innermost side and the rocking edge is substantially zero. According to this aspect, the relative speed difference between the retracting surface of the element bitten by the small-diameter pulley and the laminated band can be made substantially zero.

  The belt-type continuously variable transmission according to the present invention is a belt-type continuously variable transmission in which a belt is wound around a drive pulley and a driven pulley, and the belt is a power transmission belt according to the present invention. This is the gist.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as embodiments) will be described with reference to the drawings.

  1 to 4 are diagrams showing a schematic configuration of a belt-type continuously variable transmission including a power transmission belt 12 according to an embodiment of the present invention. FIG. 1 shows a schematic configuration of a belt-type continuously variable transmission viewed from a direction parallel to the rotation axis (center axis) of the pulley, and FIG. 2 shows a belt-type continuously variable transmission viewed from a direction orthogonal to the rotation axis of the pulley. 3 shows a part of the configuration, FIG. 3 shows a part of the configuration of the power transmission belt 12 seen from the direction parallel to the pulley rotation axis, and FIG. 4 shows the element 26 seen from the direction orthogonal to the pulley rotation axis. A schematic configuration is shown. The power transmission belt 12 according to this embodiment is wound around the drive pulley 10 and the driven pulley 11 and is driven to transmit the rotation of the drive pulley 10 to the driven pulley 11.

  The drive pulley 10 includes a movable sheave 14 that can move in a direction parallel to the rotation axis thereof, and a fixed sheave 16. The power transmission belt 12 is sandwiched between the sheave surface 14 a formed on the movable sheave 14 and the sheave surface 16 a formed on the fixed sheave 16. The sheave surface 14a of the movable sheave 14 and the sheave surface 16a of the fixed sheave 16 are inclined with respect to the pulley radial direction so that the distance between the sheave surfaces 14a, 16a is narrower toward the inner side in the pulley radial direction (wider toward the outer side in the pulley radial direction). is doing. The driven pulley 11 has the same configuration as that of the driving pulley 10.

  A thrust in a direction parallel to the rotation axis is applied to the movable sheave 14 by the supplied oil pressure. Due to this thrust, the movable sheave 14 moves in a direction parallel to the rotation axis, whereby the distance between the sheave surface 14a and the sheave surface 16a changes. At the same time, the power transmission belt 12 slides in the pulley radial direction with respect to the sheave surfaces 14a and 16a. Due to the sliding of the power transmission belt 12 in the pulley radial direction, the engagement diameters of the power transmission belt 12 to the driving pulley 10 and the driven pulley 11 are continuously changed, so that the gear ratio of the belt type continuously variable transmission is increased. Changes continuously.

  The power transmission belt 12 includes a pair of laminated bands 24 and a plurality of elements 26 arranged and supported on the pair of laminated bands 24 along the circumferential direction thereof. In the laminated band 24, a plurality of endless bands 44 are laminated in the pulley radial direction. Each element 26 comes into contact with the drive pulley 10 and the driven pulley 11 as the drive pulley 10 rotates about its rotation axis and the power transmission belt 12 is driven.

  Each element 26 includes a body portion 31 formed with a side surface 31a that comes into contact with the drive pulley 10 and the driven pulley 11 (sheave surfaces 14a, 16a), a head portion 32 disposed on the outer side in the pulley radial direction from the body portion 31, And a neck portion 33 that connects the body portion 31 and the head portion 32. The head portion 32 of each element 26 is provided with an ear portion 34, and a saddle surface 36 is formed on the body portion 31 of each element 26 so as to face the ear portion 34. In each element 26, a band receiving groove 38 is formed by the saddle surface 36, the neck portion 33, and the ear portion 34, and the laminated band 24 is passed through each band receiving groove 38, whereby each saddle surface 36 is laminated. It contacts the inner peripheral surface of the band 24. FIG. 4 shows an example in which the head portion 32 and the neck portion 33 are provided at the center portion of the element 26 in the width direction (the left-right direction in FIG. 4, the direction parallel to the rotation axis of the pulley).

  A rocking edge 35 is formed on the body portion 31 of each element 26 so as to face the element 26 adjacent to the front in the belt driving direction (one in the belt driving direction). The locking edge 35 of each element 26 extends along the width direction of the element 26. Each element 26 can swing (pitch) around the rocking edge 35 of the element 26 adjacent to the rear in the belt driving direction (the other in the belt driving direction). For example, as shown in FIG. 3, the locking edge 35 of the element 26b is opposed to the element 26a adjacent to the front in the belt driving direction, and the element 26a is the fulcrum of the locking edge 35 of the element 26b adjacent to the rear in the belt driving direction. Can be swung. In the present embodiment, the rocking edge 35 can be formed on the body portion 31 of each element 26 so as to face the element 26 adjacent to the rear in the belt driving direction. In this case, each element 26 can swing around the rocking edge 35 of the element 26 adjacent to the front in the belt driving direction.

  In the present embodiment, the saddle surface 36 of each element 26 is formed with a retracting surface 36a that is retracted inward in the band stacking direction (inward in the pulley radial direction) from the other portions. In the laminated band 24, a plurality of kinds (four kinds in the example shown in FIG. 2) of endless bands 44 having different widths are laminated in the pulley radial direction. Furthermore, in the laminated band 24, the width of the endless band 44 (for example, the endless band 44a in FIG. 2) passing through the vicinity of each of the retracting surfaces 36a is larger than the endless band 44 (for example, the endless band in FIG. 44b), the width of the endless band 44a located on the innermost side (in the band stacking direction) among the endless bands 44 stacked as the stacked band 24 is set to be the narrowest. In each element 26, the retracting surface 36 a is in contact with the innermost (narrowest) endless band 44 a in the laminated band 24. As described above, in each element 26, the retracting surface 36 a is retracted inward in the band stacking direction (locking edge 35 side) with respect to the other portions of the saddle surface 36, whereby the distance between the retracting surface 36 a and the locking edge 35. And the distance between the endless band 44a and the locking edge 35 can be shortened. 2 and 4 show examples in which the distance between the retracting surface 36a and the locking edge 35 is set to 0 (or almost 0) in each element 26. FIG. That is, an example in which the distance between the endless band 44a and the locking edge 35 is set to 0 (or almost 0) is shown. 2 and 4 show that the saddle surface 36 gradually retracts inward in the band stacking direction as the distance from the inner side in the element width direction toward the outer retracting surface 36a (the distance to the pulley rotation axis gradually decreases). In this example, the width of the film gradually decreases from the outside to the inside in the band stacking direction.

  Here, as shown in FIG. 5, when considering the case where the locking edge 35 is offset with respect to the saddle surface 36, the small diameter pulley inlet of the drive pulley 10 and the driven pulley 11 having the smaller belt engagement diameter is used. A relative speed difference is generated between the element 26 c caught in the pulley and the laminated band 24, and the element 26 c advances faster than the laminated band 24. Therefore, the frictional force from the laminated band 24 acts on the element 26c bitten by the small-diameter pulley in the belt driving direction rearward, and the rearward tilt pitching with the locking edge 35 of the succeeding element 26d adjacent rearward in the belt driving direction as a fulcrum. Occurs. By this backward pitching, the head portion of the element 26c bitten by the small-diameter pulley collides with the head portion of the subsequent element 26d. At that time, if the contact position is deviated from the center, rotation in the yaw direction with the fulcrum as the fulcrum occurs, causing deterioration of the yawing posture. Further, sliding loss (friction loss) is generated due to the relative speed difference between the element 26c and the laminated band 24 that are caught in the small-diameter pulley, so that the power transmission efficiency of the belt type continuously variable transmission is lowered.

  On the other hand, in the present embodiment, the distance between the retracting surface 36a that contacts the inner peripheral surface of the laminated band 24 and the locking edge 35 (the distance between the endless band 44a and the locking edge 35) is shortened (ideally 0). Therefore, the relative speed difference between the retracting surface 36a of the element 26 (for example, the elements 26a and 26b in FIG. 3) and the endless band 44a of the innermost layer in the laminated band 24 is reduced (see FIG. 3). Ideally 0). Therefore, the backward inclined pitching of the elements 26a and 26b caught in the small-diameter pulley can be suppressed, and the collision with the subsequent element can be reduced. As a result, deterioration of the yawing posture of the element 26 can be prevented. In the present embodiment, the friction loss between the retracting surface 36a of the elements 26a and 26b and the innermost endless band 44a in the laminated band 24 can be reduced. Therefore, the belt type continuously variable transmission It is possible to improve the power transmission efficiency.

  However, as shown in FIG. 6, when the distance between the saddle surface 36 and the locking edge 35 (the offset amount of the locking edge 35) is uniformly set to almost zero in the width direction of the element 26 (see Patent Document 1). When the pressing of the element 26 is performed, the locking edge 35 is rounded due to the occurrence of sag and the locking edge 35 is difficult to be molded, and the molding accuracy of the locking edge 35 is lowered. Therefore, the width of the locking edge 35 is narrowed, and the compressive load acting between the elements 26 is handled only by the locking edge 35 of the narrow neck portion 33. As a result, the durability of the element 26 decreases.

  On the other hand, in the present embodiment, the distance between the saddle surface 36 and the locking edge 35 changes in the width direction of the element 26. More specifically, the offset amount in the portion other than the retracting surface 36a on the saddle surface 36 is larger than the offset amount in the portion where the retracting surface 36a is formed. Therefore, even if the distance between the retracting surface 36 a and the locking edge 35 is set to 0, the width of the locking edge 35 formed in the body portion 31 can be sufficiently secured. Accordingly, in the portion of the saddle surface 36 other than the retracting surface 36a, it is possible to sufficiently secure an offset amount that does not cause the locking edge 35 to be rounded during press molding. Therefore, the locking edge 35 can be easily molded, and a decrease in the molding accuracy of the locking edge 35 can be prevented. As a result, the compressive load acting between the elements 26 can be handled by the wide locking edge 35, and the durability of the element 26 can be prevented from being lowered. Thus, according to the present embodiment, the relative speed difference between the element 26 and the laminated band 24 is reduced at the small-diameter pulley inlet without lowering the molding accuracy of the locking edge 35 and lowering the durability of the element 26. Thus, the yawing posture of the element 26 can be stabilized and the efficiency of the belt type continuously variable transmission can be improved.

  Next, another configuration example of this embodiment will be described.

  In the configuration example shown in FIGS. 7 and 8, the distance of the saddle surface 36 with respect to the rocking edge 35 changes stepwise (in two steps), and the width of the endless band 44 changes stepwise (in two steps). More specifically, the distance between the saddle surface 36 and the locking edge 35 is set to be shorter on the outer side in the element width direction (retracted surface 36a) than on the inner side in the element width direction (part other than the retracted surface 36a). The width of the endless band 44 is set narrower on the inner side in the band stacking direction (for example, the endless band 44a in FIG. 7) than on the outer side in the band stacking direction (for example, the endless band 44b in FIG. 7). FIGS. 7 and 8 also show examples in which the distance between the retracting surface 36a and the locking edge 35 (the distance between the endless band 44a and the locking edge 35) is set to 0 (or substantially 0). 7 and 8, the relative speed difference between the element 26 and the laminated band 24 can be reduced at the small-diameter pulley inlet without lowering the molding accuracy of the locking edge 35 and lowering the durability of the element 26. Can do. Further, in the configuration examples shown in FIGS. 7 and 8, the types of endless bands 44 used in the laminated band 24 can be reduced (to two types), so that an increase in cost can be suppressed.

  In the configuration example shown in FIGS. 9 and 10, the head portion 32 and the neck portion 33 are provided at both ends in the width direction of the element 26, and one laminated band 24 is in contact with the saddle surface 36. In the configuration example shown in FIG. 9, a retracting surface 36a is formed at the center of the saddle surface 36 in the element width direction. On the other hand, in the configuration example shown in FIG. 10, retracted surfaces 36 a are formed at both ends of the saddle surface 36 in the element width direction. 9 and 10 also show an example in which the distance between the retracting surface 36a and the locking edge 35 (the distance between the endless band 44a and the locking edge 35) is set to 0 (or almost 0). 9 and 10, the relative speed difference between the element 26 and the laminated band 24 can be reduced at the small-diameter pulley inlet without reducing the molding accuracy of the locking edge 35 and the durability of the element 26. Can do.

  In the above description of the embodiment, in each element 26, the distance between the endless band 44a located on the innermost side and the locking edge 35 is set to 0 (or almost 0). However, in this embodiment, in each element 26, the locking edge 35 can be slightly offset with respect to the retracting surface 36a.

  As mentioned above, although the form for implementing this invention was demonstrated, this invention is not limited to such embodiment at all, and it can implement with a various form in the range which does not deviate from the summary of this invention. Of course.

It is a figure which shows schematic structure of a belt-type continuously variable transmission provided with the belt for power transmission which concerns on embodiment of this invention. It is a figure which shows schematic structure of a belt-type continuously variable transmission provided with the belt for power transmission which concerns on embodiment of this invention. It is a figure which shows schematic structure of a belt-type continuously variable transmission provided with the belt for power transmission which concerns on embodiment of this invention. It is a figure which shows schematic structure of a belt-type continuously variable transmission provided with the belt for power transmission which concerns on embodiment of this invention. It is a figure explaining the backward inclination pitching which arises in an element when a rocking edge is offset with respect to a saddle surface. It is a figure which shows schematic structure of the belt for power transmission in which the distance of a saddle surface and a rocking edge is uniformly set to substantially 0 in the width direction of an element. It is a figure which shows the other schematic structure of a belt-type continuously variable transmission provided with the belt for power transmission which concerns on embodiment of this invention. It is a figure which shows the other schematic structure of a belt-type continuously variable transmission provided with the belt for power transmission which concerns on embodiment of this invention. It is a figure which shows the other schematic structure of a belt-type continuously variable transmission provided with the belt for power transmission which concerns on embodiment of this invention. It is a figure which shows the other schematic structure of a belt-type continuously variable transmission provided with the belt for power transmission which concerns on embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Drive pulley, 11 Driven pulley, 12 Power transmission belt, 14 Movable sheave, 14a, 16a Sheave surface, 16 Fixed sheave, 24 Laminated band, 26 Element, 31a Side surface, 35 Locking edge, 36 Saddle surface, 36a Retraction surface, 38 band receiving groove, 44 endless band.

Claims (3)

A power transmission belt that is wound around a drive pulley and a driven pulley and is driven to transmit the rotation of the drive pulley to the driven pulley,
A laminated band in which a plurality of endless bands are laminated in the pulley radial direction;
A plurality of elements arranged and supported on the laminated band along the circumferential direction, each of which is in contact with the driving pulley and the driven pulley as the driving pulley rotates,
With
Each element is formed with a locking edge facing an element adjacent to one side in the belt driving direction, and each element is swingable with the locking edge of the element adjacent to the other side in the belt driving direction as a fulcrum,
Each element has a saddle surface that contacts the inner peripheral surface of the laminated band, and each saddle surface has a recessed surface that is recessed inward in the band lamination direction.
A belt for power transmission in which the endless band located on the innermost side among the endless bands laminated as a laminated band has the smallest width. The power transmission belt according to claim 1,
The power transmission belt, wherein a distance between the endless band on the innermost peripheral side and the rocking edge is substantially zero. A belt type continuously variable transmission in which a belt is wound around a driving pulley and a driven pulley,
A belt-type continuously variable transmission, wherein the belt is a power transmission belt according to claim 1 or 2.

Images