JP2012017829A - Transmission belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmission belt for a continuously variable transmission that reduces noise, while unifying a board thickness of an element.SOLUTION: The transmission belt 10 for the continuously variable transmission includes: a number of plate-shaped elements 20 in which a dimple 28 is formed on one surface in a thickness direction and a hole 29 is formed on the other surface and which are annularly arranged with facing to each other; and an endless annular ring 30 which binds the elements 20 being annularly arranged. The dimple 28 of the adjacent element 20 is inserted into the hole 29 of the respective element 20. In addition, a difference between a width W21 in a belt inside-and-outside direction of the hole 29 and a width W11 in the belt inside-and-outside direction of the dimple 28 (W21-W11) is set to be larger than a difference between a width W22 in the belt width direction of the hole 29 and a width W12 in the belt width direction of the dimple 28 (W22-W12).

Description

  The present invention relates to a transmission belt used in a belt type continuously variable transmission.

  Generally, as a transmission (for example, a transmission for an automobile) provided in a driving force transmission system that transmits a driving force from a driving source such as an engine, a stepped transmission that can change a gear ratio stepwise A continuously variable transmission capable of continuously changing the gear ratio, that is, steplessly, is known. As the latter continuously variable transmission, a belt type continuously variable transmission and a toroidal continuously variable transmission are known. Among them, the belt-type continuously variable transmission includes a driving pulley and a driven pulley, and a transmission belt wound around these pulleys, and the transmission ratio is stepless by changing the winding radius of the transmission belt with respect to each pulley. It has a configuration to change.

  As a transmission belt used in such a belt-type continuously variable transmission, a convex portion is formed on one surface in the thickness direction, a concave portion is formed on the other surface, and arranged in an annular shape facing each other. One having a large number of plate-like elements (also called blocks) and an endless annular ring (also called a hoop, band, or carrier) that binds elements arranged in a ring shape is known (for example, Patent Document 1).

  When such a transmission belt is wound around the drive side pulley and the driven side pulley and the drive side pulley is driven to rotate, the frictional force of the contact portion between the element and the drive side pulley and the driving force are applied to the element. In accordance with the torque of the side pulley, a compressive force acts in the element stacking direction applied to the element from the driving pulley, that is, in the thickness direction of the element. Then, the compressive force transmitted to the element in contact with the driving pulley is transmitted to the element in contact with the driven pulley via the element not in contact with the pulley. When compressive force is transmitted to the element that is in contact with the driven pulley, the friction force at the contact portion between the element and the driven pulley and the torque that rotates the driven pulley according to the transmitted compressive force are generated. To do. In this way, power is transmitted between the driving pulley and the driven pulley via the transmission belt.

  In addition, in the belt linear portion that is linearly arranged without the element being wound around the driving pulley and the driven pulley, by inserting the convex portion of the element adjacent to the concave portion of the element, the adjacent elements Relative positioning is performed. Thereby, rattling at the belt linear portion of the transmission belt can be suppressed, and stable running of the element can be realized.

Japanese Patent Laid-Open No. 01-055447

  In the transmission belt as described above, noise may be generated when an element that has advanced along the belt linear portion is bitten by the driving pulley. Further, there is a concern that the noise increases as the timing (biting period) at which the element is bitten by the driving pulley is uniform. According to the transmission belt described in Patent Document 1, two or more types of elements having different plate thicknesses are randomly arranged to shift the timing at which the elements are engaged with the driving pulley, thereby reducing the noise. ing. However, in order to manufacture two or more types of elements having different plate thicknesses, two or more types of steel plates having different plate thicknesses are required, which raises a problem of cost.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a transmission belt for a continuously variable transmission that can reduce noise while unifying the plate thickness of an element.

  In the present invention, means for solving the above-described problems are configured as follows. That is, according to the present invention, a convex portion is formed on one surface in the thickness direction, a concave portion is formed on the other surface, and a large number of plate-like elements arranged annularly facing each other, A transmission belt for a continuously variable transmission including an endless annular ring that binds the elements in an arrayed state, and a convex portion of an adjacent element is inserted into a concave portion of each element, The difference between the width of the concave portion in the belt inner and outer direction and the width of the convex portion in the belt inner and outer direction is larger than the difference between the width of the concave portion in the belt width direction and the width of the convex portion in the belt width direction. It is a feature.

  According to the above configuration, the relative movement of the adjacent elements in the belt width direction of the adjacent belt in the belt linear portion of the transmission belt is restricted, while the relative movement of the adjacent elements in the belt inner and outer directions is allowed. For this reason, in the belt linear part of a transmission belt, it becomes possible to advance in the state which the adjacent element shifted | deviated to the belt inside / outside direction. In other words, it is possible to vary the position of the element traveling in the belt linear portion in the belt inner / outer direction. And the timing (biting period) at which the element that has advanced along the belt straight portion is bitten by the driving pulley of the continuously variable transmission can be varied. Thereby, the noise (belt noise) generated when the element is bitten by the driving pulley can be reduced. In addition, since all the elements used in the transmission belt can have the same shape, the plate thickness of the elements can be unified, and the manufacturing cost of the transmission belt can be reduced.

  Here, as the specific shapes of the convex portions and concave portions of each element, the shape of the convex portion of each element is a circular cross section, and the concave portion of each element is an elliptical cross section in the belt inner and outer direction. It can be a shape extending along.

  According to the present invention, it is possible to vary the position of the element traveling in the belt linear portion in the belt inner and outer directions, and to determine the timing at which the element traveling in the belt linear portion is bitten by the driving pulley of the continuously variable transmission. Can be scattered. Thereby, the noise generated when the element is bitten by the driving pulley can be reduced. In addition, since all the elements used in the transmission belt can have the same shape, the plate thickness of the elements can be unified, and the manufacturing cost of the transmission belt can be reduced.

It is a figure which shows schematic structure of the belt-type continuously variable transmission in which the power transmission belt to which this invention is applied is used. It is a figure which shows schematic structure of the transmission belt which concerns on embodiment of this invention, Comprising: The front view of the element assembled | attached with respect to the ring is shown. FIG. 3 is an X1-X1 sectional view of the element of FIG. 2. It is a figure which shows typically the dimensional relationship of the dimple and hole of each element. It is a side view which shows typically an example of the positional relationship of the element which adjoins in the belt linear part of a transmission belt. It is a figure corresponding to FIG. 2 of the power transmission belt which concerns on other embodiment of this invention. It is X2-X2 sectional drawing of the element of FIG. It is a figure corresponding to FIG. 5 of the power transmission belt which concerns on other embodiment of this invention.

  Embodiments of the present invention will be described with reference to the accompanying drawings.

  First, a belt type continuously variable transmission 100 using a transmission belt 10 to which the present invention is applied will be described with reference to FIG. In the belt type continuously variable transmission 100, the transmission belt 10 is wound around a driving pulley 101 attached to a driving shaft (input shaft) and a driven pulley 102 attached to a driven shaft (output shaft). Driven to transmit the rotation of the pulley 101 to the driven pulley 102.

  The driving pulley 101 and the driven pulley 102 are each provided with a pair of sheaves 103 and 103 (see FIG. 2) whose groove width can be changed steplessly. The sheaves 103, 103 are inclined with respect to the pulley radial direction so that the distance between the sheave surfaces becomes narrower toward the inner side in the pulley radial direction (wider toward the outer side in the pulley radial direction). Then, by changing the groove width, that is, the interval between the sheave surfaces, by the hydraulic circuit controlled according to the running state of the vehicle, the wrapping radius of the transmission belt 10 with respect to the driving pulley 101 and the driven pulley 102 changes. . Thereby, in the belt-type continuously variable transmission 100, the rotation speed ratio between the drive shaft and the driven shaft, that is, the gear ratio changes continuously.

  Specifically, when the groove width of the driving pulley 101 is increased to reduce the winding radius of the transmission belt 10 and the groove width of the driven pulley 102 is decreased to increase the winding radius of the transmission belt 10. Increases the gear ratio. Conversely, when the groove width of the driving pulley 101 is reduced to increase the winding radius of the transmission belt 10 and the groove width of the driven pulley 102 is increased to reduce the winding radius of the transmission belt 10. As a result, the gear ratio is reduced.

  Next, with reference to FIGS. 1-4, the power transmission belt 10 used for the belt-type continuously variable transmission 100 is demonstrated. 2 and 4, the left-right direction (belt width direction) in the figure is the x direction. In FIG. 3, the left-right direction (belt traveling direction) in the figure is the y direction. 2 to 4, the upper direction (belt outer surface side direction) in the vertical direction (belt inner / outer direction) is defined as the z1 direction, and the lower direction (belt inner surface side direction) is defined as the z2 direction.

  As shown in FIG. 1, the transmission belt 10 includes a large number of plate-like elements 20 arranged in the thickness direction (y direction in FIG. 3) and the elements 20 arranged in an annular shape. The structure includes an endless annular ring 30 to be bound. The element 20 is made of, for example, a metal plate-like member, and is manufactured by punching using a press. In this embodiment, the elements 20 have the same shape.

  As shown in FIGS. 2 and 3, the element 20 has a base portion (main body portion) 22 in which the left and right side surfaces 21 and 21 in the width direction (x direction in FIG. 2) are formed as tapered inclined surfaces. is doing. The side surface 21 of the base 22 is a friction surface against the sheave that contacts the sheave 103 and is a tapered surface that matches the sheave surface of the sheave 103.

  A neck portion 23 extending upward (in the z1 direction in FIGS. 2 and 3) of the element 20 is formed at the left and right central portions in the width direction (x direction in FIG. 2) of the base body portion 22. A head portion 24 extending in an umbrella shape is formed integrally with the neck portion 23 on the left and right sides in the width direction of the base portion 22 at the upper end portion of the neck portion 23. Between the upper edge portion of the base portion 22 and the lower edge portion of the head portion 24, slit portions (groove portions) 25, 25 opened in the left-right direction are formed. The slit portions 25, 25 are arranged on both the left and right sides in the width direction with the neck portion 23 interposed therebetween. Rings 30 and 30 are inserted into the left and right slit portions 25 and 25, respectively. The ring 30 is, for example, a so-called laminated ring formed by laminating a plurality of metal annular strips. The upper edge portion of the base portion 22 is a saddle surface 26 that comes into contact with the inner peripheral surface (innermost layer surface) of the ring 30. A clearance C <b> 5 is provided between the outer peripheral surface (outermost layer surface) of the ring 30 and the head 24.

  The elements 20 are bound by the rings 30 and 30 in an annularly arranged state, and are in contact with the driving pulley 101 and the driven pulley 102 in this state. In a state where the pulleys 101 and 102 are in contact with each other, the element 20 needs to expand in a fan shape (radial) with respect to the centers of the pulleys 101 and 102 and be in close contact with each other. The lower part 3 (the part on the center side in an annular arrangement) is formed thin.

  Specifically, from a portion that is lowered (offset) by a predetermined dimension from the saddle surface 26 on one surface (for example, the left surface in FIG. 3) in the thickness direction (y direction in FIG. 3) of the base portion 22. The lower part is thinned in a shape that is cut off. Therefore, in the belt bending portion 11 of the transmission belt 10 in which each element 20 spreads in a fan shape and comes into contact, in other words, each element 20 is wound around each pulley 101, 102 and arranged in an arc shape, Touch at the changing boundary. The edge of this boundary part is a so-called rocking edge 27. The locking edge 27 extends along the width direction of the element 20.

  In addition, relative to the element 20 at the belt linear portion 12 of the transmission belt 10 in which each element 20 is arranged linearly without being wound around the pulleys 101 and 102 at the left and right central portions in the width direction of the head 24. A convex portion (dimple) 28 and a concave portion (hole) 29 for determining a proper position are formed. Specifically, a convex frustoconical dimple 28 is formed on one surface of the element 20 (the surface having the locking edge 27 in FIG. 3). A hole 29 for loosely fitting (free fitting) the dimple 28 of the adjacent element 20 is formed on the other surface of the element 20 (the surface without the locking edge 27 in FIG. 3). One dimple 28 and one hole 29 are provided in each element 20. The dimple 28 and the hole 29 are formed by, for example, pressing. The belt linear portion 12 of the transmission belt 10 includes a belt linear portion on the side where the element 20 approaches the driving pulley 101 (upper side in FIG. 1) and a side where the element 20 moves away from the driving pulley 101 (lower side in FIG. 1). Side) belt straight part. Of these, each element 20 is in an uncompressed state at the belt linear portion 12 closer to the driving pulley 101, and each element 20 is in a compressed state at the belt linear portion 12 away from the driving pulley 101.

  In this embodiment, in the transmission belt 10 configured as described above, the difference between the width W21 of the hole 29 of each element 20 in the belt inner and outer direction and the width W11 of the dimple 28 in the belt inner and outer direction is the width W22 of the hole 29 in the belt width direction. And the width W12 of the dimple 28 in the belt width direction. Hereinafter, this point will be described in detail.

  As shown in FIG. 3, the dimple 28 of each element 20 has a trapezoidal cross section when cut along a plane perpendicular to the belt width direction, and cut along a plane perpendicular to the belt traveling direction as shown in FIG. The cross-sectional shape at this time is circular. Further, as shown in FIG. 3, the hole 29 of each element 20 has a trapezoidal cross-sectional shape when cut along a plane orthogonal to the belt width direction, and a cross-sectional shape when cut along a plane orthogonal to the belt traveling direction. However, as shown in FIG. 4, it is formed in an oval shape extending in the belt inner / outer direction.

  As shown in FIG. 4, the width W21 in the belt inner and outer direction of the hole 29 of each element 20 is larger than the width W11 of the dimple 28 in the belt inner and outer direction (W21> W11). The width W22 of each element 20 in the belt width direction of the hole 29 is larger than the width W12 of the dimple 28 in the belt width direction (W22> W12). The difference (W21−W11) between the width W21 of the hole 29 of each element 20 in the belt inside / outside direction and the width W11 of the dimple 28 in the belt inside / outside direction is the width W22 of the hole 29 in the belt width direction and the belt width of the dimple 28. It is larger than the difference (W22−W12) from the width W12 in the direction.

  In the belt linear portion 12 of the transmission belt 10, the dimples 28 of the adjacent elements 20 are inserted into the holes 29 of the elements 20. Since the dimensional relationship between the dimple 28 and the hole 29 of each element 20 is set as described above, a clearance is generated between the dimple 28 and the hole 29 of the adjacent elements 20 and 20. For the sake of convenience, the clearance between the dimple 28 and the hole 29 will be described with reference to FIG. In FIG. 4, the clearance between the dimple 28 and the hole 29 is exaggerated.

  In the example of FIG. 4, clearances C <b> 1 and C <b> 2 are provided on both sides of the dimple 28 in the belt inner / outer direction. Further, clearances C3 and C4 are provided on both sides of the dimple 28 in the belt width direction. The sum (C1 + C2) of the clearances C1 and C2 in the belt inner and outer directions is made larger than the sum (C3 + C4) of the clearances C3 and C4 in the belt width direction. The sum (C1 + C2) of the clearances C1 and C2 in the belt inner and outer directions is made smaller than the clearance C5 provided between the outer peripheral surface (outermost layer surface) of the ring 30 and the head 24 described above.

  The clearances C3 and C4 in the belt width direction are made as small as possible in order to limit the relative movement in the belt width direction of the adjacent elements 20 and 20 in the belt linear portion 12 of the transmission belt 10 as much as possible. On the other hand, the dimples 28 are movable in the hole 29 in the belt inner and outer directions by the clearances C1 and C2 in the belt inner and outer directions. For this reason, relative movement of the adjacent elements 20, 20 in the belt linear portion 12 in the belt inner and outer directions is allowed. In this case, the relative movement of the adjacent elements 20 and 20 in the belt linear portion 12 in the belt inner and outer directions is possible within the range of the sum of the clearances C1 and C2 in the belt inner and outer directions (C1 + C2).

  For this reason, in the belt linear portion 12 of the transmission belt 10, for example, as shown in FIG. 5, it is possible to proceed with the adjacent elements 20 and 20 being displaced in the belt inner and outer directions. In other words, the position of the element 20 traveling in the belt linear portion 12 in the belt inner / outer direction can be varied. Then, it is possible to vary the timing (engagement cycle) at which the element 20 that has advanced along the belt linear portion 12 is bitten by the driving pulley 101. Specifically, when the adjacent elements 20 and 20 are shifted in the belt inner and outer directions and the element 20 is engaged with the driving pulley 101, the center of the driving pulley 101 to the locking edge 27 of the element 20. The distance at which the element 20 is engaged with the driving pulley 101 can be varied. Thereby, the noise (belt noise) generated when the element 20 is bitten by the driving pulley 101 can be reduced.

  In addition, in this embodiment, the dimple 28 of each element 20 is a circular protrusion, and the hole 29 of each element 20 is a long hole extending inward and outward of the belt, so that all the elements 20 used in the transmission belt 10 are the same. It can be made into the shape. Thereby, the plate | board thickness of the element 20 can be unified, and the type | mold of the press which processes the dimple 28 and the hole 29 can also be unified. Therefore, the manufacturing cost of the transmission belt 10 can be reduced.

-Other embodiments-
The present invention is not limited only to the above-described embodiments, and all modifications and applications within the scope of the claims and within the scope equivalent to the scope are possible.

  The shape of the convex portion (dimple) 28 and the shape of the concave portion (hole) 29 of the element 20 described above are examples, and can be variously changed. In short, the shape of the dimple 28 and the shape of the hole 29 regulate the relative movement in the belt width direction of the adjacent elements 20 and 20 in the belt linear portion 12, while restricting the relative movement of the adjacent elements 20 and 20 in the belt inner and outer directions. Various changes can be made as long as the shape is acceptable.

  In the above, the example in which the present invention is applied to the transmission belt having the element 20 having the shape as shown in FIG. 2 is shown in the front view, but the transmission having the element 120 having the shape as shown in FIG. The present invention can also be applied to a belt. In the element 120 shown in FIG. 6, the positional relationship between dimples, holes, and rings in the belt inner and outer directions is opposite to that of the element 20 shown in FIG.

  A transmission belt according to another embodiment of the present invention will be briefly described with reference to FIGS. 1 and 6 to 8. FIG. 6 is a diagram showing a schematic configuration of the transmission belt 10 according to another embodiment of the present invention, and shows a front view of the element 120 assembled to the ring 130. 7 is an X2-X2 cross-sectional view of the element 120 of FIG. FIG. 8 is a side view schematically illustrating an example of the positional relationship between the adjacent elements 120 and 120 in the belt linear portion 12 of the transmission belt 10. In FIG. 6, the left-right direction (belt width direction) in the figure is the x direction. In FIG. 7, the left-right direction (belt traveling direction) in the figure is the y direction. 6 and 7, the up direction (belt outer surface side direction) of the vertical direction (belt inner and outer directions) is defined as the z1 direction, and the lower direction (belt inner surface side direction) is defined as the z2 direction.

  The transmission belt 10 includes a large number of plate-like elements 120 arranged in the thickness direction (y direction in FIG. 7) with the same posture, and an endless annular ring 130 that binds the elements 120 arranged in an annular shape. (Refer to FIG. 1).

  As shown in FIGS. 6 and 7, the element 120 has a base portion (main body portion) 122 in which left and right side surfaces 121, 121 in the width direction (x direction in FIG. 6) are formed as tapered inclined surfaces. is doing. The side surface 121 of the base portion 122 is a friction surface against the sheave that contacts the sheave 103 and is a tapered surface that matches the sheave surface of the sheave 103.

  Column portions 123 extending in the upward direction of the element 120 (the z1 direction in FIGS. 6 and 7) are formed on the left and right ends of the base portion 122 in the width direction (x direction in FIG. 6), respectively. ing. Therefore, the upper end surface, that is, the upper edge portion of the base portion 122 in FIGS. 6 and 7, and the inner side surfaces 123 a and 123 a of the left and right column portions 123 and 123, that is, the upper side of the element 120, that is, the transmission belt 10. A recess (fitting groove) 125 opened on the outer surface side (belt outer surface side) is formed. At the upper end portions of the left and right column parts 123, 123, protrusions 124, 124 in which the left and right tip surfaces 124 a, 124 a extend toward the center in the width direction of the base part 122 are integrally formed.

  The concave portion 125 is a portion for inserting and accommodating endless annular rings 130, 130 for binding the elements 120, 120,. The bottom surface of the recess 125 is a saddle surface 126 with which the inner peripheral surfaces of the rings 130 and 130 come into contact. A clearance C <b> 6 is provided between the outer peripheral surface (outermost layer surface) of the ring 130 and the protrusion 124.

  The elements 120 are bound by the rings 130 and 130 in an annular arrangement, and are in contact with the driving pulley 101 and the driven pulley 102 in this state. In a state in which the pulleys 101 and 102 are in contact with each other, the element 120 expands in a fan shape (radial shape) with respect to the centers of the pulleys 101 and 102 and needs to be in close contact with each other. The lower part 7 (the part on the center side in an annular arrangement) is formed thin.

  Specifically, from a portion that is lowered (offset) by a predetermined dimension from the saddle surface 126 on one surface (for example, the left surface in FIG. 6) in the thickness direction (y direction in FIG. 7) of the base portion 122. The lower part is thinned in a shape that is cut off. Therefore, in the belt bending portion 11 of the transmission belt 10 in which each element 120 expands and contacts in a fan shape, in other words, each element 120 is wound around each pulley 101 and 102 and arranged in an arc shape, Touch at the changing boundary. The edge of this boundary portion is a so-called rocking edge 127. The locking edge 127 extends along the width direction of the element 120.

  Further, at the left and right central portions in the width direction of the base portion 122, the elements 120 are relative to the belt straight portions 12 of the transmission belt 10 in which the elements 120 are linearly arranged without being wound around the pulleys 101 and 102. A convex portion (dimple) 128 and a concave portion (hole) 129 for determining a proper position are formed. Specifically, a convex dimple 128 is formed on one surface of the element 120 (the surface having the locking edge 127 in FIG. 7). A hole 129 for loosely fitting (free fitting) the dimple 128 of the adjacent element 120 is formed on the other surface of the element 120 (the surface without the locking edge 127 in FIG. 7). One dimple 128 and one hole 129 are provided for each element 120. The dimple 128 and the hole 129 are formed by, for example, pressing. For example, the dimple 128 of each element 120 has a trapezoidal cross-sectional shape when cut along a plane orthogonal to the belt width direction, and a circular cross-sectional shape when cut along a plane orthogonal to the belt traveling direction. The hole 129 of each element 120 has a trapezoidal cross-sectional shape when cut along a plane orthogonal to the belt width direction, and the cross-sectional shape when cut along a plane orthogonal to the belt traveling direction is along the belt inner and outer directions. It is formed in an oval shape that extends.

  Also in this embodiment, as in the above embodiment, the difference between the width of the hole 129 of each element 120 in the belt inner and outer direction and the width of the dimple 128 in the belt inner and outer direction is the width of the hole 129 in the belt width direction. The difference between the dimple 128 and the width in the belt width direction is made larger (see FIG. 4). Thereby, also in this embodiment, the effect similar to the said embodiment is acquired. That is, in the belt linear portion 12 of the transmission belt 10, for example, as shown in FIG. 8, it is possible for the adjacent elements 120, 120 to proceed in a state of being shifted in the belt inner and outer directions. In other words, the position of the element 120 traveling in the belt linear portion 12 in the belt inner / outer direction can be varied. And it becomes possible to vary the timing (biting cycle) at which the element 120 that has advanced along the belt straight portion 12 is bitten by the driving pulley 101. Thereby, the noise (belt noise) generated when the element 120 is bitten by the driving pulley 101 can be reduced. Moreover, all the elements 120 used for the transmission belt 10 can be made into the same shape. Thereby, the plate | board thickness of the element 120 can be unified, and the type | mold of the press which processes the dimple 128 and the hole 129 can also be unified. Therefore, the manufacturing cost of the transmission belt 10 can be reduced.

  INDUSTRIAL APPLICABILITY The present invention is a transmission belt for a continuously variable transmission, and can be used for a transmission belt in which a large number of plate-like elements arranged in an annular shape facing each other are bound together by an endless ring. is there.

10 Transmission belt 20 Element 28 Dimple (convex part)
29 holes (concave)
30 ring 100 continuously variable transmission

Claims (2)

A convex portion is formed on one surface in the thickness direction, a concave portion is formed on the other surface, and a large number of plate-like elements arranged in an annular shape facing each other;
A transmission belt for a continuously variable transmission comprising an endless annular ring that binds elements arranged in an annular shape,
In the concave portion of each element, the convex portion of an adjacent element can be inserted,
The difference between the width of the concave portion of each element in the belt inside / outside direction and the width of the convex portion in the belt inside / outside direction is made larger than the difference between the width of the concave portion in the belt width direction and the width of the convex portion in the belt width direction. A transmission belt characterized by The power transmission belt according to claim 1,
The convex portion of each element is formed in a circular cross section,
The power transmission belt according to claim 1, wherein the concave portion of each element is formed in an oval cross section and extends along the inside and outside of the belt.

Images