JP2009085411A - Belt for continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain wear on a contact section between a metal element and a pulley and changes of torque transmitting capacity with the pulley at a low level in spite of yawing of the metal element on a belt for a continuously variable transmission. <P>SOLUTION: The belt for a continuously variable transmission comprises two sets of metal ring assemblies, and a plurality of the metal elements 60, and a plurality of metal elements 60 supported by the metal ring assembly while it is fitted with each set of the metal ring assembly. Each metal element 60 provides a pair of pulley contact surfaces 82 at a section including a thickness-directional middle section with both side faces in the width direction of facing a pair of pulley elements organizing a pulley on both side faces in the width direction. Each pulley contact surface 82 is formed at a curved surface with a cross-sectioned arc shape. The radius curvature direction of the pulley contact surface 82 is a direction orthogonal to a generatrix 80 of the pulley contact surface 82. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a continuously variable transmission belt that includes an annular member and a plurality of metal elements supported in a state of fitting with the annular member, and is used in a state of being spanned between two pulleys. .

  Conventionally, it has been considered to use a belt-type continuously variable transmission as a transmission for a vehicle such as an automobile. The continuously variable transmission has a belt between two pulleys, and changes the groove width of each pulley, thereby changing the belt winding diameter and changing the gear ratio between the two pulleys. Can be changed steplessly.

  As such a continuously variable transmission, a conventional structure described in Patent Document 1 is known. FIG. 13 is a schematic diagram of a power transmission system of a vehicle including a continuously variable transmission of an example of a conventional structure described in Patent Document 1. 14 is a partial perspective view of a metal belt constituting the continuously variable transmission of FIG. 15 is a cross-sectional view taken along line AA in FIG.

  As shown in FIG. 13, the continuously variable transmission 10 includes a drive pulley 12 and a driven pulley 14, and a metal belt 16 is wound between the drive pulley 12 and the driven pulley 14. The continuously variable transmission 10 is disposed between the engine 18 and the drive wheels 20 in the power transmission direction. When the driving force of the engine 18 is transmitted to the driven shaft 32 via the crankshaft 22, the damper 24, the input shaft 26, the starting clutch 28, the drive shaft 30, the drive pulley 12, the metal belt 16, and the driven pulley 14. Has been. The driving force transmitted to the driven shaft 32 is transmitted to the drive wheel 20 via the forward drive gear 34 or the reverse drive gear 36 and the output shaft 38.

  The drive pulley 12 includes a fixed-side pulley half 40 and a movable-side pulley half 42, and the movable-side pulley half 42 can contact and separate from the fixed-side pulley half 40. The driven pulley 14 includes a fixed pulley half 44 and a movable pulley half 46, and the movable pulley half 46 can contact and separate from the fixed pulley half 44.

  As shown in FIG. 14, the metal belt 16 is formed by supporting a number of metal elements 50 on a pair of metal ring assemblies 48. In addition, the front-back direction, the left-right direction, and the radial direction of the metal element 50 are defined as shown in FIG. That is, the radial direction is defined as the radial direction of the drive pulley 12 or the driven pulley 14 (hereinafter simply referred to as the pulley 12 (14) in the description of FIGS. 13 to 15) with which the metal element 50 abuts. The side closer to the rotational axis of (14) is the radially inner side, and the side away from the rotational axis of the pulley 12 (14) is the radially outer side. Further, the left-right direction is defined as a direction along or parallel to the rotation axis of the pulley 12 (14) with which the metal element 50 abuts, and the front-rear direction is defined as a direction along the traveling direction of the metal element 50.

  The metal element 50 includes an element main body 52 provided on the radially inner side and an ear part 54 provided on the radially outer end. In addition, a pair of pulley contact surfaces 56 that can contact the V surface of the pulley 12 (14) are formed at both left and right ends of the element body 52. Further, a convex portion 57 is formed on the front side surface of the ear portion 54 and a concave portion (not shown) is formed on the rear side surface, and the metal belt 16 (FIG. 13) is formed, and the metal element 50 on the front side in the traveling direction is formed. A convex portion 57 formed on the metal element 50 on the rear side in the traveling direction can be fitted into the concave portion.

  Further, as shown in FIG. 15, a flat surface 58 is formed on the rear side of the element main body 52 (lower side of FIG. 15), and at the left and right ends of the front side of the element main body 52 (upper side of FIG. 15). A pair of protrusions 59 are formed. When the metal element 50 is wound around the pulley 12 (14), the flat surface 58 of the metal element 50 on the front side in the traveling direction (upper side in FIG. 15) and the metal element 50 on the rear side in the traveling direction (lower side in FIG. 15). The left and right protrusions 59 come into contact. Thereby, yawing of the metal element 50 is prevented, and the metal element 50 is prevented from being obliquely engaged with the V surfaces of the pulleys 12 and 14 and being damaged. When a pressing force exceeding a predetermined torque is applied, the left and right protrusions 59 of the metal element 50 are completely crushed and the front side surface and the rear side surface are in close contact with each other.

JP 2001-27288 A

  In the case of the conventional structure described in Patent Document 1 shown in FIGS. 13 to 15, there is room for improvement in terms of suppressing wear between the metal element 50 and the pulley 12 (14). That is, in the continuously variable transmission 10 shown in FIG. 13, a gap called an initial gap is provided in at least a part between the plurality of metal elements 50 (FIGS. 14 and 15) in order to assemble the belt. It has been regarded as a compulsory item. For this reason, among the metal belts 16, there are also gaps between the plurality of metal elements 50 located in the portion called the chord portion, which is the portion between the drive pulley 12 called the primary pulley and the driven pulley 14 called the secondary pulley. As a result, this gap may become larger with long-term use. In particular, the gap between the metal elements 50 tends to be large at the portion returning from the driven pulley 14 to the drive pulley 12 in the portion called the string portion.

  Further, since the string portion of the metal belt 16 swings in the radial direction or the left-right direction, which is a direction orthogonal to the traveling direction, the metal element 50 (FIGS. 14 and 15) constituting the string portion also has various directions. Inertial force acts. Further, due to the change in the gear ratio of the continuously variable transmission 10, there is a possibility that the center position in the width direction of the pulley groove constituted by the V surface is shifted between the drive pulley 12 and the driven pulley 14, respectively. There is also a possibility that an inertial force acts on the metal element 50 in a direction orthogonal to the traveling direction. As a result, the gap between the metal elements 50 is increased as described above, and under the situation where such an inertial force acts on the metal element 50, the conventional structure shown in FIGS. It is difficult to maintain the intended posture of the metal element 50. Further, once the attitude of the metal element 50 changes in the string portion, the attitude becomes difficult to return to the normal state, and the metal element 50 is greatly inclined with respect to the traveling direction, that is, in a state of yawing with a large inclination angle. As it is, it enters the pulley groove of the pulley 12 (14). And when the pulley contact surface 56 which contacts a pulley groove of a metal element is made into the flat surface, the edge part of the pulley contact surface 56 and the surface of a pulley groove hit corner, and the metal element 50 and each each The pulleys 12 and 14 may be worn.

  In the case of the above conventional structure, the protrusion 59 (FIG. 15) formed on the front side surface of the metal element 50 is brought into contact with the flat surface 58 (FIG. 15) formed on the rear side surface of the metal element 50 on the front side in the traveling direction. It is said that yawing of the metal element 50 is prevented, but it is difficult to expect the effect of preventing yawing under the situation where a gap is generated between the metal elements 50 as described above. 12 (14), there is room for improvement from the aspect of suppressing wear.

  In the belt for continuously variable transmission, regardless of the yawing of the metal element, the wear at the contact portion between the metal element and the pulley is suppressed, and the change in the torque transmission capacity between the pulley and the pulley is suppressed. With the goal.

  A continuously variable transmission belt according to the present invention includes an annular member and a plurality of metal elements supported in a state of being fitted to the annular member, and is used in a state of being spanned between two pulleys. The belt for a continuously variable transmission, wherein each metal element is provided in a portion including a middle portion in the thickness direction which is a traveling direction on both side surfaces in the width direction facing a pair of pulley elements constituting each pulley. A belt for a continuously variable transmission, comprising a pair of pulley contact surfaces, each pulley contact surface being formed in a curved surface having an arcuate cross section.

  Preferably, each pulley contact surface is a curved surface in which the radius of curvature at one end in the height direction on the outer peripheral side of the belt is larger than the radius of curvature at the other end in the height direction on the inner peripheral side of the belt. It is formed in a shape.

  More preferably, each pulley contact surface is formed in a curved surface in which the radius direction of curvature is oriented in a direction perpendicular to the generatrix direction.

  More preferably, the radius of curvature at one end in the height direction on the outer peripheral side of the belt of each pulley contact surface is R0, and the virtual plane orthogonal to the width direction of each metal element and the bus bar of each pulley contact surface When the angle formed is α, a position that is a distance d from one end to the other side with respect to the height direction of each pulley contact surface in the entire range from one end in the height direction to the other end in the height direction of each pulley contact surface. The shape of each pulley contact surface is regulated so that the radius of curvature Ra of each pulley contact surface at is Ra = R0−d · sin α.

  Further, in the continuously variable transmission belt according to the present invention, each pulley contact surface has the other end in the height direction in which the radius of curvature at the one end in the height direction on the outer peripheral side of the belt is on the inner peripheral side of the belt. Each pulley contact surface is formed in a curved shape in which the radius direction of curvature is directed in the width direction of each metal element.

  The height direction, width direction, and thickness direction of the metal element are defined as follows. That is, the height direction is defined corresponding to the radial direction of FIG. 14, which is the radial direction of the pulley with which the metal element abuts. Further, the width direction is defined corresponding to the right / left direction in FIG. 14, which is a direction along or parallel to the rotation axis of the pulley with which the metal element abuts. Moreover, the thickness direction is defined corresponding to the front-rear direction in FIG. 14, which is the direction along the traveling direction of the metal element. Such definitions are the same throughout the following description and claims.

  According to the continuously variable transmission belt according to the present invention, each metal element includes a pair of pulley contact surfaces provided on a portion including the intermediate portion in the thickness direction which is the traveling direction on both side surfaces in the width direction, Since the pulley contact surface is formed in a curved surface having an arcuate cross section, even when each metal element is inclined with respect to the traveling direction, that is, when yawing, the end of the pulley contact surface and the surface of the pulley element are angled. It is difficult to hit, and it is possible to effectively prevent an excessive contact surface pressure acting between each metal element and the pulley element. For this reason, the wear at the contact portion between the metal element and the pulley can be kept small regardless of the yawing of the metal element.

  Further, even when the attitude of the metal element at the time of contact between the metal element and the pulley element changes due to yawing, the change in the friction coefficient between the metal element and the pulley element can be reduced. For this reason, the change of the torque transmission capacity between the belt and the pulley can be reduced or eliminated regardless of the yawing of the metal element. In addition, such an effect obtained by the present invention is not limited to the case where the thicknesses of the respective metal elements are all the same, but can be obtained even when the thickness of some of the metal elements is different from the thickness of the other metal elements. be able to.

  Each pulley contact surface is formed in a curved shape in which the radius of curvature at one end in the height direction on the outer peripheral side of the belt is larger than the radius of curvature at the other end in the height direction on the inner peripheral side of the belt. In accordance with the configuration in which each pulley contact surface is in contact with each other, corresponding to the shape of the conical pulley inclined surface provided on each pulley element, the bus contact surface of each pulley contact surface extends in the width direction of the metal element. In contrast, the wear at the contact portion with the mating surface when the metal element yaws can be more effectively suppressed to a smaller value even when the metal element yaws despite being oriented in a direction inclined with respect to the orthogonal virtual plane.

[First Embodiment]
Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings. 1 to 6 show a first embodiment of the present invention. FIG. 1 is a schematic view of a metal element constituting the continuously variable transmission belt of the present embodiment as viewed in the thickness direction, which is the traveling direction. 2 is a cross-sectional view taken along the line BB in FIG. FIG. 3 is a diagram specifically illustrating the metal element of FIG. 1. 4 is a view of the element body of FIG. 3 as viewed from one side in the width direction to the other side. FIG. 5 is a partial perspective view showing a state in which a plurality of metal elements enter between a pair of pulley elements in a state where the continuously variable transmission belt of the present embodiment is assembled to the continuously variable transmission. FIG. FIG. 6 is an enlarged equivalent view of a portion C in FIG. 5 showing a state in which some metal elements are yawed.

  Further, in the present embodiment, the basic configuration itself of the power transmission system of an automobile, which is a vehicle, that includes a continuously variable transmission that uses a continuously variable transmission belt and the continuously variable transmission is described above. The configuration is the same as that shown in FIG. In particular, the feature of the present invention is that the metal element 60, which is a belt for a continuously variable transmission, is devised in the shape of the metal element 60 constituting the metal belt 16 (see FIG. 13). 60 and the drive pulley 12 (see FIG. 13) or the driven pulley 14 (see FIG. 13) (hereinafter simply referred to as the pulley 12 (14)) at the contact portion between the metal element 60 and the pulley 12 (14). Is to suppress the change in torque transmission capacity with the pulley 12 (14). For this reason, in the following description, it demonstrates centering around the structure of the metal belt 16, especially the metal element 60. FIG.

  The metal belt 16 (see FIG. 13) is supported by the metal ring assembly 48 in a state of being fitted to the two sets of metal ring assemblies 48 (see FIG. 14), which are annular members, and the metal ring assemblies 48 of each set. A plurality of metal elements 60 are provided. The metal ring assembly 48 has the same configuration as that shown in FIG. 13 described above, and is formed by laminating a plurality of metal ring elements connected in a thin plate shape and in an annular shape.

  The metal belt 16 (see FIG. 13) is used in a state of being stretched between the drive pulley 12 (see FIG. 13) and the driven pulley 14 (see FIG. 13). Allows transmission of power to The continuously variable transmission 10 (see FIG. 13) changes the winding diameter of the metal belt 16 on each pulley 12 and 14 by changing the width of the pulley groove formed by the V surface of each pulley 12 and 14. As a result, the gear ratio between the pulleys 12 and 14 can be changed steplessly. Each pulley 12, 14 includes a pair of pulley elements 61 (FIG. 5) facing each other, and a metal element 60 is interposed between the conical pulley inclined surfaces 62 (FIG. 5) provided on each pulley element 61. Can be held. Each pulley element 61 corresponds to the fixed-side pulley halves 40, 44 or the movable-side pulley halves 42, 46 shown in FIG. 13, and a pair of pulley elements 61 facing each other are arranged coaxially. .

  As shown in FIG. 1, each metal element 60 is made by punching a metal material and forming it. The metal element 60 has an ear portion 63 having a substantially triangular cross section provided on one side in the height direction (upper side in FIG. 1), An element main body 64 provided on the other side in the vertical direction (the lower side in FIG. 1), and a neck portion 66 that connects the ear portion 63 and the element main body 64 are provided. In each metal element 60, slot portions 68 are provided on both sides of the neck portion 66 in the width direction (left and right direction in FIG. 1), and each of the two metal rings can be fitted into each slot portion 68.

  The height direction, the width direction, and the thickness direction of the metal element 60 are defined as shown in FIGS. That is, the height direction is defined corresponding to the radial direction of the pulley 12 (14) with which the metal element 60 abuts. The width direction is defined as a direction along or parallel to the rotation axis of the pulley 12 (14) with which the metal element 60 abuts, and the thickness direction is defined as a direction along the traveling direction of the metal element 60. Further, the front side and the rear side correspond to the front side and the rear side in the traveling direction, respectively.

  Further, the locking surface 70 is a flat surface located on a virtual plane orthogonal to the traveling direction on the front side surface (front side surface in FIG. 1) of one end portion in the height direction of the element body 64 (upper end portion in FIG. 1). Is provided. In addition, an inclined surface 72 that is inclined with respect to the locking surface 70 is provided on the front side surface of the other side in the height direction of the element main body 64 (the lower side portion in FIG. 1) from the locking surface 70 via a linear locking edge 74. It is continuous. Further, a flat surface 76 (FIG. 2) on a virtual plane orthogonal to the traveling direction is provided on the rear side surface (back side surface in FIG. 1) of the element body 64 over almost the entire surface. In a state where the metal belt 16 (see FIG. 13) is configured, the front locking surface 70 and the rear flat surface 76 can be brought into contact with each other between the metal elements 60 adjacent in the traveling direction.

  Although not shown in FIG. 1, a convex portion 57 (see FIG. 3) is provided on the front side surface of the ear portion 63 of the metal element 60, and a concave portion 71 (see FIG. 7) is provided on the rear side surface of the ear portion 63. ing. In a state where the metal belt 16 (see FIG. 13) is configured, the convex portions 57 and the concave portions 71 can be fitted between the metal elements 60 adjacent to each other in the traveling direction.

  Further, on both sides of the element body 64 in the width direction (left and right direction in FIG. 1), on the other side portion in the height direction (lower side portion in FIG. A pair of pulley contact surfaces 82 in which the bus 80 is inclined is provided. Each pulley contact surface 82 is configured to be able to contact a conical pulley inclined surface 62 (see FIG. 5) provided in each of a pair of pulley elements 61 (see FIG. 5) constituting the pulley 12 (14).

  As shown in FIGS. 1 and 2, each pulley contact surface 82 is a thickness in the traveling direction at the lower part of each side surface in the width direction facing each pulley element 61 (see FIG. 5) of each metal element 60. The pulley contact surfaces 82 are formed in a curved surface having a circular arc cross section. The radius of curvature of each pulley contact surface 82 is set as follows. That is, when the metal element 60 is sandwiched between a pair of pulley elements 61 (see FIG. 5) constituting the pulley 12 (14), the direction of the radius of curvature of each pulley contact surface 82 is the respective pulley element. The radius of curvature of each pulley contact surface 82 is set so as to be orthogonal to the pulley inclined surface 62 (see FIG. 5) provided at 61. That is, the radius of curvature of each pulley contact surface 82 is set to face in a direction orthogonal to the direction of the bus 80 of the pulley contact surface 82.

  In addition, the radius of curvature at one end in the height direction on the outer peripheral side of the metal belt 16 (see FIG. 13) of each pulley contact surface 82 is R0, and the virtual plane z orthogonal to the width direction of each metal belt 16 Each pulley contact in the entire range from one end in the height direction to the other end in the height direction of each pulley contact surface 82 when the flank angle is α, which is an angle formed with the bus 80 of each pulley contact surface 82. The shape of each pulley contact surface 82 is set such that the radius of curvature Ra of each pulley contact surface 82 at a distance d from one end to the other side with respect to the height direction of the surface 82 is Ra = R0−d · sin α. Is regulated. Here, when the total length in the height direction of the pulley contact surface 82 is D, d is in the range of 0 ≦ d ≦ D. Further, in the entire range of each pulley contact surface 82, the curvature centers O <b> 1 and O <b> 2 are located on the same straight line in the height direction (vertical direction in FIG. 1), which is located at the center in the width direction of the metal element 60.

  In order to define the pulley contact surface 82 in this way, as shown in FIG. 2, the outer periphery of the pulley contact surface 82 is located on the same imaginary circle at different positions in the height direction of the pulley contact surface 82. It becomes an arc. Moreover, the curvature radius in the height direction one end part of each pulley contact surface 82 is larger than the curvature radius in the height direction other end part. That is, the radius of curvature of each pulley contact surface 82 gradually increases from the other side in the height direction of each pulley contact surface 82 toward the one side in the height direction.

  FIGS. 3 to 4 are more specific views of the structure shown in FIGS. Further, in the structure of FIGS. 3 to 4, the shape and function of the characteristic part of the present embodiment, including the shape of the pulley contact surface 82, are the same as the structure shown in FIGS. Are given the same reference numerals, and duplicate descriptions are omitted. 4 is a view of the element body 64 of FIG. 3 as viewed from one side in the width direction (right side in FIG. 3) to the other side (left side in FIG. 3). Parallel groove portions 88 are formed. In the case of the metal element 60 shown in FIGS. 3 to 4 as well, the pair of pulley contact surfaces 82 provided on both side surfaces in the width direction has a pulley contact surface 82 having an arcuate cross section over almost the entire surface.

  According to such a continuously variable transmission belt of the present embodiment, the wear at the contact portion between the metal element 60 and the pulley 12 (14) is suppressed to a small value regardless of the yawing of the metal element 60, and the pulley 12 ( 14), the change in torque transmission capacity can be kept small. Next, this will be described in detail with reference to FIGS.

  As shown in FIG. 5, in a state where a plurality of metal elements 60 are sandwiched between a pair of pulley elements 61 constituting the pulley 12 (14), some of the metal elements 60 are advanced as shown in FIG. Consider a state of tilting with a certain yawing angle S with respect to the direction (P direction in FIG. 6), that is, yawing. Even in such a case, in the present embodiment, as shown by a U portion in FIG. 5, the pulley contact surface 82 having a circular arc cross section in a portion including the middle portion in the thickness direction on both side surfaces in the width direction of each metal element 60. Therefore, it is possible to effectively prevent the metal element 60 from hitting the pulley inclined surface 62 at the corner of the pulley contact surface 82. For this reason, it can prevent effectively that the contact surface pressure which acts between the pulley contact surface 82 and the pulley inclined surface 62 becomes excessive. Therefore, regardless of the yawing of the metal element 60, the wear at the contact portion between the metal element 60 and the pulley 12 (14) can be reduced.

  Further, even when the posture of the metal element 60 at the time of contact between the metal element 60 and the pulley inclined surface 62 is changed by yawing, the metal element 60 easily contacts the pulley inclined surface 62 uniformly. A change in the friction coefficient μ between the pulley inclined surfaces 62 can be suppressed to a small value. For this reason, regardless of the yawing of the metal element 60, the change in the torque transmission capacity between the metal belt 16 (see FIGS. 5 and 13) and the pulley 12 (14) can be reduced or eliminated.

  In addition, the effect obtained by this embodiment is not limited to the case where the thicknesses of the metal elements 60 are the same, and the thickness of some of the metal elements 60 is different from the thickness of the other metal elements 60. Even in the case, it can be obtained similarly. For example, the thickness of one metal element 60 among the plurality of metal elements 60 is set to a small thickness, and the thickness of the remaining metal elements 60 is set to a large thickness. Then, by configuring the metal belt 16 (see FIGS. 5 and 13) to include or exclude the metal element 60 having a small thickness, the gap between the metal elements 60 of the metal belt 16 is reduced. It can also be adjustable. In such a case, the thickness of some of the metal elements 60 is different from the thickness of the other metal elements 60. However, as in the case described above, the metal elements 60 and the pulleys 12 are irrespective of the yawing of the metal elements 60. The wear at the contact portion of (14) can be reduced, and the change in torque transmission capacity with the pulley 12 (14) can be reduced.

  The radius of curvature of each pulley contact surface 82 at one end in the height direction on the outer peripheral side of the metal belt 16 (see FIGS. 5 and 13) is the other end in the height direction on the inner peripheral side of the metal belt 16. It is larger than the radius of curvature at the part. For this reason, the bus 80 (FIG. 1) of each pulley contact surface 82 is a metal element corresponding to the shape of the conical pulley inclined surface 62 provided in each pulley element 61 with which each pulley contact surface 82 contacts. In spite of being inclined with respect to the virtual plane z (FIG. 1) orthogonal to the width direction of 60, the wear at the contact portion with the mating surface when the metal element 60 yaws is further increased. It can be effectively kept small.

  On the other hand, the case of the conventional structure considered from the past which deviates from this invention is demonstrated using FIGS. 7 and 8 are views corresponding to FIGS. 5 and 6 in the conventional structure, and FIG. 7 shows a state in which the plurality of metal elements 50 have entered the pulley groove of the pulley 12 (14) in the conventional structure. FIG. 3 is a partial schematic cross-sectional view showing a part thereof. FIG. 8 is an enlarged view corresponding to a portion E in FIG. 7 showing a state where some of the metal elements 50 are yawed. 7 and 8, the arrow P direction is the front side in the traveling direction.

  In the conventional structure shown in FIGS. 7 and 8, the pulley contact surfaces 84 provided on both side surfaces in the width direction of the metal element 50 are simply flat surfaces, and are formed in curved surfaces unlike the case of the present embodiment. Absent. As shown in FIGS. 7 and 8, the cross-sectional shape of the metal element 50 including the pair of pulley contact surfaces 84 is a rectangular shape. For this reason, as shown by a V portion in FIG. 8, the pulley contact surface 84 easily hits the pulley slope 62 in a state where some of the metal elements 50 are yawed with a certain yawing angle S. When some of the metal elements 50 yaw in this way, only the metal element 50 having the largest yawing angle S among the plurality of metal elements 50 is sandwiched between the pair of pulley slopes 62. Therefore, the surface pressure acting between the pulley inclined surface 62 and the metal element 50 may be excessive. For this reason, the pulley 12 (14) and the metal element 50 are likely to be worn. When the metal element 50 is not yawing, each metal element 50 comes into contact with the pulley inclined surface 62 on the two-dot chain line T in FIG. For this reason, in the case of the conventional structure shown in FIGS. 7 to 8, there is room for improvement in terms of suppressing wear between the metal element 50 and the pulley 12 (14). On the other hand, according to the present embodiment shown in FIGS. 1 to 6 described above, the pulley contact surface 82 is formed in a curved surface having an arcuate cross section, so that such inconvenience can be eliminated.

  Next, FIG. 9 shows a calculation result performed by the present inventor in order to confirm the effect obtained by the present embodiment. In a comparative example that deviates from the present invention, R is applied to the corners at both ends in the width direction of the metal element. It is a figure shown by the relationship between the radius of the corner of the comparative example, which is the radius of curvature of the R portion when the portion is provided, and the maximum surface pressure ratio at the contact portion between the metal element and the pulley slope. FIG. 10 is a schematic diagram showing a state in which the R portion 90 provided on the metal element 60 of the comparative example is in contact with the pulley inclined surface 62. Here, the “comparative example” is a pulley contact surface 82 (FIGS. 1 to 3) provided on both sides in the width direction of the metal element 60 in the same configuration as the present embodiment shown in FIGS. ) Is a flat pulley contact surface 84 which does not form a curved central portion in the thickness direction, and an R portion 92 is provided at a corner located at the end of the pulley contact surface 84 in the thickness direction. Is.

  The “maximum surface pressure ratio” is the R of the pulley contact surface 84 of the metal element 60 in the comparative example with respect to the maximum contact surface pressure acting between the metal element 60 and the pulley inclined surface 62 in the present embodiment. The ratio of the maximum contact surface pressure acting between the R portion 92 and the pulley inclined surface 62 when the portion 92 contacts the pulley inclined surface 62 is said.

  As is clear from the calculation result shown in FIG. 9, when the radius of the corner of the comparative example, which is the radius of curvature of the R portion 92 (FIG. 10) of the metal element 60 (FIG. 10) of the comparative example, is increased, The maximum surface pressure ratio is smaller than that in the case where the corner radius of the comparative example is small, and the maximum contact surface pressure acting between the metal element 60 and the pulley slope 62 (FIG. 10) is small. However, even when the comparative example corner radius of the metal element 60 of the comparative example is increased to 0.15 mm, the maximum surface pressure ratio increases to about 10. That is, in the present embodiment, when the maximum contact surface pressure acting between the metal element 60 and the pulley slope 62 is 1, and in the case of the comparative example, the maximum pressure acting between the pulley slope 62 is set. The contact surface pressure becomes extremely large at about 10. In other words, in the case of this embodiment, in contrast to the comparative example in which the central portion in the thickness direction of the pulley contact surface 84 is not formed into a curved surface, the radius of the corner of the comparative example is 0.15 mm or less. It has been found that the maximum contact surface pressure acting between the pulley contact surface 82 (FIG. 1) and the pulley slope 62 can be reduced to about 1/10 or less. In the first embodiment described above, the corners located at both ends in the thickness direction of each pulley contact surface 82 of each metal element 60 can be provided with the R portion, but the R portion is omitted. You can also.

[Second Embodiment]
11 to 12 show a second embodiment of the present invention. FIG. 11 is a schematic view of a metal element 60a constituting the metal belt 16 (see FIG. 13), which is a continuously variable transmission belt according to the present embodiment, viewed in the thickness direction that is the traveling direction. . 12 is a cross-sectional view taken along line FF in FIG. In the case of the present embodiment, the direction in which the radius direction of curvature of the pulley contact surface 82a faces is different in each metal element 60a constituting the first embodiment. That is, in the present embodiment, the pair of pulley contact surfaces 82a provided on both side surfaces in the width direction of each metal element 60a is formed in a curved surface, and the direction of the radius of curvature of the pulley contact surface 82a is the height direction. (Vertical direction in FIG. 11) and a thickness direction (back and front direction in FIG. 11) and a curved surface facing the width direction (left and right direction in FIG. 11) perpendicular to the thickness direction.

  Further, each of the pulley contact surfaces 82a has a radius of curvature at one end in the height direction (upper end in FIG. 11) on the outer peripheral side of the metal belt 16 (see FIG. 13), and is a virtual plane orthogonal to the width direction. All of the pulley contact surfaces 82a extending from one end in the height direction to the other end (the lower end in FIG. 11) when the flank angle is α ′, which is an angle formed between z and the bus 80 of each pulley contact surface 82a. In this range, the radius of curvature Ra ′ of each pulley contact surface 82a at a distance d from one end to the other side in the height direction of each pulley contact surface 82a is Ra ′ = R0′−d · sin ( The shape of each pulley contact surface 82a is regulated so that α ′). Here, when the total length in the height direction of the pulley contact surface 82 is D, d is in the range of 0 ≦ d ≦ D.

  In order to define the pulley contact surface 82a in this way, as shown in FIG. 12, the outer periphery of the pulley contact surface 82a is located on the same imaginary circle at different positions in the height direction of the pulley contact surface 82a. It becomes an arc. In addition, the radius of curvature at one end in the height direction of each pulley contact surface 82a is larger than the radius of curvature at the other end in the height direction. That is, the radius of curvature of each pulley contact surface 82a gradually increases from the other side in the height direction of the pulley contact surface 82a (lower side in FIG. 11) toward one side in the height direction (upper side in FIG. 11). Yes.

  In the case of this embodiment as well, as in the first embodiment, regardless of the yawing of the metal element 60a, the contact portion between the metal element 60a and the pulley 12 (14) (see FIG. 13). Can be kept small, and a change in torque transmission capacity with the pulley 12 (14) can be kept small. Since other configurations and operations are the same as those of the first embodiment shown in FIGS. 1 to 6 described above, the same parts are denoted by the same reference numerals, and overlapping illustrations and descriptions are omitted.

It is a schematic diagram at the time of seeing the metal element which comprises the belt for continuously variable transmission of the 1st Embodiment of this invention in the thickness direction which is an advancing direction. It is BB sectional drawing of FIG. It is a figure which shows the metal element of FIG. 1 concretely. It is the figure which looked at the element main body of FIG. 3 from the width direction one side to the other side. The partial schematic cross-section showing a state in which a plurality of metal elements enter between a pair of pulley elements in a state where the continuously variable transmission belt of the first embodiment is assembled to the continuously variable transmission. FIG. FIG. 6 is an enlarged equivalent view of a portion C in FIG. 5, showing a state in which some metal elements are yawing. FIG. 10 is a partial schematic cross-sectional view showing a state in which a plurality of metal elements have entered a pulley groove of a pulley in a conventional structure, partially seen through. It is the E section enlarged equivalent view of Drawing 7 showing the state where a part of metal element yawed. The calculation results performed for confirming the effect obtained by the first embodiment are shown in the comparative example end corner radius in the comparative example deviating from the present invention, and the maximum surface pressure ratio at the contact portion between the metal element and the pulley slope. FIG. It is the schematic which shows the state which R part provided in the metal element of the comparative example is contacting the pulley slope. It is a schematic diagram at the time of seeing the metal element which comprises the belt for continuously variable transmission of 2nd Embodiment in the thickness direction which is an advancing direction. It is FF sectional drawing of FIG. 1 is a schematic diagram of a power transmission system of a vehicle including a continuously variable transmission of an example of a conventional structure. It is a fragmentary perspective view of the metal belt which comprises the continuously variable transmission of FIG. It is AA sectional drawing of FIG.

Explanation of symbols

10 continuously variable transmission, 12 drive pulley, 14 driven pulley, 16 metal belt, 18 engine, 20 drive wheel, 22 crankshaft, 24 damper, 26 input shaft, 28 clutch for starting, 30 drive shaft, 32 driven shaft, 34 Forward drive gear, 36 Reverse drive gear, 38 Output shaft, 40 Fixed pulley half, 42 Movable pulley half, 44 Fixed pulley half, 46 Movable pulley half, 48 Metal ring assembly, 50 Metal element, 52 Element body, 54 Ear part, 56 Pulley contact surface, 57 Convex part, 58 Flat surface, 59 Projection part, 60, 60a Metal element, 61 Pulley element, 62 Pulley slope, 63 Ear part, 64 Element body 66 neck, 6 Slot portion 70 locking surface 71 recess 72 inclined surface 74 the locking edge, 76 flat surface, 80 bus, 82 and 82a pulley contact surface 84 a pulley contact surface, 88 groove, 92 R unit.

Claims (5)

An annular member;
A plurality of metal elements supported in a state of being fitted to an annular member,
A continuously variable transmission belt used in a state of being stretched between two pulleys,
Each metal element includes a pair of pulley contact surfaces provided in a portion including a middle portion in the thickness direction which is a traveling direction of both side surfaces in the width direction facing the pair of pulley elements constituting each pulley,
Each pulley contact surface is formed into a curved surface having a circular arc cross section. The continuously variable transmission belt according to claim 1,
Each pulley contact surface is formed in a curved surface in which the radius of curvature at one end in the height direction on the outer peripheral side of the belt is larger than the radius of curvature at the other end in the height direction on the inner peripheral side of the belt. A continuously variable transmission belt. The continuously variable transmission belt according to claim 2,
Each pulley contact surface is formed into a curved surface in which the radius of curvature is oriented in a direction perpendicular to the generatrix direction. The continuously variable transmission belt according to claim 3,
The radius of curvature at one end in the height direction on the outer peripheral side of the belt of each pulley contact surface is R0, and the angle formed between the virtual plane orthogonal to the width direction of each metal element and the generatrix of each pulley contact surface is α. Each pulley contact surface in a range extending from one end in the height direction to the other end in the height direction with respect to the height direction of each pulley contact surface, each pulley contact surface at a distance d from one end to the other side The belt for continuously variable transmission is characterized in that the shape of each pulley contact surface is regulated so that the curvature radius Ra of Ra = R0−d · sin α. The continuously variable transmission belt according to claim 2,
Each pulley contact surface is formed in a curved surface in which the radius of curvature is directed in the width direction of each metal element.

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