JP2012233504A - Toroidal continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toroidal continuously variable transmission that can improve traction performance in a high-load operation and maintain durability on a traction surface, in response to a change of a contact surface of a power roller 11 in the high-load operation.SOLUTION: In the toroidal continuously variable transmission, texture processing is applied to either or both region(s) of outer diameter 115 and inner diameter 116, except for a near region where a surface pressure is maximum in the contact surface 112 of the side of the power roller 11 in the high load operation.

Description

  The present invention relates to a toroidal continuously variable transmission that can be used for transmissions of automobiles and various industrial machines.

  For example, a double-cavity toroidal continuously variable transmission used as a transmission for an automobile is configured as shown in FIGS. As shown in FIG. 5, an input shaft 1 is rotatably supported inside the casing 50, and two input side disks 2, 2 and two output side disks 3 are disposed on the outer periphery of the input shaft 1. 3 is attached. An output gear 4 is rotatably supported on the outer periphery of the intermediate portion of the input shaft 1. Output side disks 3 and 3 are connected to cylindrical flange portions 4a and 4a provided at the center of the output gear 4 by spline coupling.

  The input shaft 1 is rotationally driven by a drive shaft 22 via a loading cam type pressing device 12 provided between an input side disk 2 and a cam plate 7 located on the left side in the drawing. . The output gear 4 is supported in the casing 50 via a partition wall 13 formed by coupling two members, so that the output gear 4 can rotate around the axis O of the input shaft 1 while the axis O. Directional displacement is prevented.

  The output side disks 3 and 3 are supported by needle bearings 5 and 5 interposed between the input shaft 1 so as to be rotatable about the axis O of the input shaft 1. Further, the left input side disk 2 in the figure is supported on the input shaft 1 via a ball spline 6, and the right side input disk 2 in the figure is splined to the input shaft 1. Rotates with the input shaft 1. A power roller 11 (see FIG. 6) is rotatably held between the inner side surfaces 2a and 2a of the input side disks 2 and 2 and the inner side surfaces 3a and 3a of the output side disks 3 and 3.

  A step 2b is provided on the inner peripheral surface 2c of the input side disk 2 located on the right side in FIG. 5, and the step 1b provided on the outer peripheral surface 1a of the input shaft 1 is abutted against the step 2b. At the same time, the back surface (right surface in FIG. 5) of the input side disk 2 is abutted against the loading nut 9. Thereby, the displacement of the input side disk 2 in the direction of the axis O with respect to the input shaft 1 is substantially prevented. Further, a disc spring 8 is provided between the cam plate 7 and the flange portion 1d of the input shaft 1, and this disc spring 8 is connected to the inner side surfaces 2a, 2a, A pressing force is applied to the abutting portions between 3a, 3a and the peripheral surfaces 11a, 11a of the power rollers 11, 11.

  6 is a cross-sectional view taken along line AA in FIG. As shown in FIG. 6, inside the casing 50, a pair of trunnions 15, 15 are provided that swing (tilt) about a pair of pivots 14, 14 that are twisted with respect to the input shaft 1. Yes. In addition, illustration of the input shaft 1 is abbreviate | omitted in FIG. Each trunnion 15, 15 is formed at a pair of ends formed in the longitudinal direction (vertical direction in FIG. 6) of the support plate portion 16 that supports the power roller 11 in a state of being bent toward the inner surface side of the support plate portion 16. It has the bent wall parts 20 and 20. The bent wall portions 20 and 20 form concave pocket portions P for accommodating the power rollers 11 in the trunnions 15 and 15. Further, the pivot shafts 14 and 14 are concentrically provided on the outer side surfaces of the bent wall portions 20 and 20, respectively.

  A circular hole 21 is formed at the center of the support plate portion 16, and a base end portion 23 a of the displacement shaft 23 is supported in the circular hole 21. Then, by swinging each trunnion 15, 15 about each pivot 14, 14, the inclination angle of the displacement shaft 23 supported at the center of each trunnion 15, 15 can be adjusted. Further, each power roller 11 is rotatably supported through a radial needle bearing around the tip 23b of the displacement shaft 23 protruding from the inner surface of each trunnion 15, 15. Is sandwiched between the input disks 2 and 2 and the output disks 3 and 3. In addition, the base end part 23a and the front-end | tip part 23b of each displacement shaft 23 and 23 are mutually eccentric.

  Further, the pivot shafts 14, 14 of the trunnions 15, 15 are supported so as to be swingable with respect to the pair of yokes 23A, 23B and displaceable in the axial direction (vertical direction in FIG. 6). The horizontal movement of the trunnions 15 and 15 is restricted by 23B. Each yoke 23A, 23B is formed in a rectangular shape by pressing or casting a metal such as steel. Each of the yokes 23A and 23B is provided with two circular support holes 18, and the pivot shafts 14 provided at both ends of the trunnion 15 swing through the radial needle bearings 30 in the support holes 18 ( Tilt) is supported freely. In addition, a circular locking hole 19 is provided in the central portion of the yokes 23A and 23B in the width direction (left and right direction in FIG. 5), and the inner peripheral surface of the locking hole 19 is a spherical surface having a cylindrical surface. Posts 64 and 68 are internally fitted. That is, the upper yoke 23A is swingably supported by the post 64 supported by the casing 50 via the fixing member 52, and the lower yoke 23B is the post 68 and the drive cylinder 31 that supports the post 68. The upper cylinder body 61 is swingably supported.

  The displacement shafts 23 and 23 provided in the trunnions 15 and 15 are provided at positions 180 degrees opposite to the input shaft 1. In addition, the direction in which the distal end portion 23b of each of the displacement shafts 23 and 23 is eccentric with respect to the base end portion 23a is the same direction as the rotational direction of both the disks 2, 2, 3 and 3 (in FIG. (Reverse direction). Further, the eccentric direction is a direction substantially orthogonal to the direction in which the input shaft 1 is disposed. Accordingly, the power rollers 11 and 11 are supported so that they can be slightly displaced in the longitudinal direction of the input shaft 1. As a result, even if each power roller 11, 11 tends to be displaced in the axial direction of the input shaft 1 due to elastic deformation of each component member based on the thrust load generated by the pressing device 12, each component This displacement is absorbed without applying an excessive force to the member.

  A thrust ball bearing 24 and a thrust needle bearing 25 are provided between the outer surface of the power roller 11 and the inner surface of the support plate 16 of the trunnion 15 in order from the outer surface side of the power roller 11. ing. Among these, the thrust ball bearing 24 supports the rotation of each power roller 11 while supporting the load in the thrust direction applied to each power roller 11. Each of such thrust ball bearings 24 includes a plurality of balls (hereinafter referred to as rolling elements) 26, 26, an annular retainer 27 that holds the rolling elements 26, 26 in a freely rolling manner, And an annular outer ring 28. Further, the inner ring raceway of each thrust ball bearing 24 is formed on the outer side surface of each power roller 11, and the outer ring raceway is formed on the inner side surface of each outer ring 28.

  The thrust needle bearing 25 is sandwiched between the inner surface of the support plate portion 16 of the trunnion 15 and the outer surface of the outer ring 28. Such a thrust needle bearing 25 supports the thrust load applied to each outer ring 28 from the power roller 11, while the power roller 11 and the outer ring 28 swing around the base end portion 23 a of each displacement shaft 23. Allow.

  Further, drive rods 29 and 29 are provided at one end portions (lower end portions in FIG. 6) of the trunnions 15 and 15, respectively, and drive pistons 33 and 33 are fixed to the outer peripheral surface of the intermediate portion of each drive rod 29 and 29. It is installed. Each of these drive pistons 33 and 33 is oil-tightly fitted in a drive cylinder 31 constituted by an upper cylinder body 61 and a lower cylinder body 62. The drive pistons 33 and 33 and the drive cylinder 31 constitute a drive device 32 that displaces the trunnions 15 and 15 in the axial direction of the pivots 14 and 14.

  In the case of the toroidal continuously variable transmission configured as described above, the rotation of the input shaft 1 is transmitted to the input side disks 2 and 2 via the pressing device 12. Then, the rotation of the input side disks 2 and 2 is transmitted to the output side disks 3 and 3 via the pair of power rollers 11 and 11, and the rotation of the output side disks 3 and 3 is further transmitted to the output gear 4. Is taken out and transmitted to the output shaft 40.

  When changing the rotational speed ratio between the input shaft 1 and the output gear 4, the pair of drive pistons 33, 33 are displaced in opposite directions. As the drive pistons 33 and 33 are displaced, the pair of trunnions 15 and 15 are slightly displaced in directions opposite to each other. For example, the power roller 11 on the left side of FIG. 6 is slightly displaced toward the lower side of the figure, and the power roller 11 on the right side of the figure is slightly displaced toward the upper side of the figure. As a result, the peripheral surfaces 11a and 11a of the power rollers 11 and 11 act on contact portions of the input side disks 2 and 2 and the inner side surfaces 2a, 2a, 3a and 3a of the output side disks 3 and 3, respectively. The direction of the tangential force changes slightly. As the force changes, the trunnions 15 and 15 swing (tilt) in opposite directions around the pivots 14 and 14 pivotally supported by the yokes 23A and 23B.

  As a result, the contact position between the peripheral surfaces 11a and 11a of the power rollers 11 and 11 and the inner surfaces 2a and 3a changes, and the gear ratio between the input shaft 1 and the output gear 4 changes. Further, when the torque transmitted between the input shaft 1 and the output gear 4 fluctuates and the amount of elastic deformation of each component changes, the power rollers 11 and 11 and the outer rings attached to the power rollers 11 and 11 will be described. 28 and 28 are slightly rotated around the base end portions 23a and 23a of the displacement shafts 23 and 23, respectively. Since the thrust needle bearings 25 and 25 exist between the outer side surfaces of the outer rings 28 and 28 and the inner side surfaces of the support plate portions 16 constituting the trunnions 15 and 15, respectively, the rotation is performed smoothly. Is called. Therefore, as described above, the force for changing the inclination angle of each displacement shaft 23, 23 can be small.

  By the way, in the toroidal type continuously variable transmission having the above-described configuration, power transmission between the power roller 11 and the input / output side disks 2 and 3 passes through an oil film in order to prevent damage to the surface of these members. Performed by traction force. (In this specification, the interface between the power roller 11 formed by an oil film and the input / output side disks 2, 3, or the inner side surfaces 2 a, 3 a of the input / output side disks 2, 3 and the peripheral surface of the power roller 11 11a itself is called a traction surface). The traction force increases in proportion to the traction coefficient determined by the state of the interface, the thickness of the oil film, etc. and the surface pressure of the interface.

  Conventionally, in order to increase the traction coefficient, it has been proposed to texture the traction surface to form fine irregularities (such as dimples) and fine grooves. On the other hand, when texture processing is performed, depending on the conditions, the contact surface pressure locally increases, which may cause the traction surface to deteriorate such as peeling of the traction surface or surface damage due to oil film breakage. is there. Therefore, the device about the shape and formation position of a texture process is proposed (for example, refer patent document 1).

Japanese Patent Laid-Open No. 2002-089644

  In the toroidal-type continuously variable transmission, a large shearing force is generated at the contact surface between the power roller 11 and the input / output side disks 2 and 3 during high load operation (note that the power roller 11 and the input / output side disks 2 and 3 are in contact with each other). Is not in direct contact because an oil film is sandwiched between them, but in this specification, the surface on which both are pressed is referred to as a contact surface). In order to reduce the slip of the contact surface against this large shearing force, the pressing force between the power roller 11 and the input / output side disks 2 and 3 is increased, or the traction coefficient of the contact surface is increased to increase the traction force. It is necessary to raise.

  However, in order to increase the pressing force between the power roller 11 and the input / output side disks 2 and 3, it is necessary to increase the rigidity of each component member, which increases the size and weight of the entire apparatus. In recent years, for example, in order to improve the fuel efficiency of automobiles equipped with toroidal-type continuously variable transmissions, downsizing and weight reduction of toroidal-type continuously variable transmissions have been demanded. It becomes impossible to meet this demand. Furthermore, when the pressing force is increased, there is a disadvantage that the driving loss generated in each bearing increases.

  On the other hand, when texture processing is applied to the range of contact surfaces between the power roller 11 and the input / output side disks 2 and 3 in order to increase the traction coefficient, the durability of the traction surface may be lowered depending on the conditions as described above. I will invite you. Deterioration of the traction surface due to texture processing is most likely to occur during maximum load operation where the shear force of the contact surface increases.

  The power roller is designed so that a certain range contacts the input / output disk when the rigidity of each component is assumed to be infinite. It has been found that the position of the contact surface slightly changes between operation and high load operation.

  The present invention has been made in view of the above circumstances, and among the contact surfaces of the power roller and the input / output side disk, the position of the contact surface on the power roller side changes between high load operation and low load operation. Accordingly, an object of the present invention is to provide a toroidal continuously variable transmission capable of improving the traction performance during high-load operation and maintaining the durability of the traction surface.

  In order to achieve the above object, the invention according to claim 1 is directed to an input side disk and an output side disk that are supported concentrically and rotatably with the respective inner surfaces facing each other, and A power roller sandwiched between the input-side disk and the output-side disk; and an output shaft that rotates when power is transmitted from the output-side disk, the power roller, the input-side disk, and the output-side disk. In the toroidal type continuously variable transmission in which power is transmitted by a traction force via an oil film formed on the contact surface with the power roller, the power roller serving as the contact surface during high load operation in which a predetermined amount of load is applied to the output shaft One or both of the range on the inner diameter side and the outer diameter side of the range except the range that overlaps the vicinity of the site where the maximum surface pressure occurs Wherein the texture processing is given.

  In the first aspect of the invention, attention is paid to the fact that the components around the trunnion are elastically deformed during high load operation and the position of the contact surface on the power roller side changes, and the power roller side during high load operation Texture processing is performed on both sides or one side of the contact surface except the vicinity of the maximum surface pressure portion. By this texture processing, the traction coefficient of the contact surface at the time of high load operation can be increased, and the traction performance at the time of high load operation can be improved. In addition, when there is texture processing, a portion without texture processing appears in the maximum surface pressure portion during high load operation that may cause deterioration of the traction surface. Therefore, the durability of the traction surface can be maintained without the above-described deterioration.

  The invention according to claim 2 is characterized in that, in the invention according to claim 1, texture processing is performed only in a range on the outer diameter side.

  In the second aspect of the present invention, only during high load operation in which a large shear force is generated on the traction surface, a part where the texture processing of the power roller appears on the contact surface and the shear force gradually weakens to a medium load. At the time of driving, the part with the texture processing does not appear at the maximum surface pressure part of the contact surface. Therefore, even during operation from high load to medium load, it is possible to avoid deterioration of the traction surface due to texture processing, and the durability of the traction surface can be reliably maintained.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the predetermined amount of load is a predetermined maximum rated load.

  In the third aspect of the invention, it is possible to improve the traction performance and maintain the durability of the traction surface during the operation with the maximum rated load.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the texture processing is processing for forming fine irregularities or fine grooves.

  In the invention according to the fourth aspect, the traction coefficient of the portion textured by the fine irregularities or fine grooves can be reliably increased.

  According to the toroidal-type continuously variable transmission of the present invention, traction performance during high-load operation can be improved by texture processing applied to the peripheral surface of the power roller. Furthermore, by limiting the position where the texture processing is performed as described above, it is possible to avoid the deterioration of the traction surface due to the texture processing and maintain the durability of the traction surface.

It is sectional drawing which shows the power roller and its periphery in the toroidal type continuously variable transmission which concerns on embodiment of this invention. The contact surface on the power roller side and the texture processing range are shown. (A) is a two-dimensional graph representing the area of the contact surface, and (b) is a graph representing the surface pressure of the contact surface. It is a side view which shows the range which texture-processes among the surrounding surfaces of a power roller. It is a two-dimensional graph which shows the modification of the range which performs a texture process among the contact surfaces by the side of a power roller. It is sectional drawing which shows an example of the specific structure of the half toroidal type continuously variable transmission conventionally known. It is sectional drawing which follows the AA line of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  The feature of the present invention resides in the position where the peripheral surface 11a of the power roller 11 is textured, and the other configurations and operations are the same as the conventional configurations and operations described above. Therefore, in the following, only the characteristic part of the present invention will be referred to, and other parts will be simply described with the same reference numerals as those in FIGS.

  FIG. 1 shows a power roller 11 and its periphery in a toroidal-type continuously variable transmission according to an embodiment of the present invention. As shown in FIG. 1, of the contact surfaces between the power roller 11 and the input / output side disks 2, 3, the contact surface on the power roller 11 side has contact surfaces 111, 112 depending on the load applied to the output shaft 40. The position changes as follows. That is, during low load operation where the output shaft 40 is not so heavily loaded, the trunnion 15 and its surrounding components are not significantly affected by the load on the output side. Therefore, the contact surface 112 of the power roller 11 is substantially the same as that at the time of stopping and is an ellipsoid centered on the axis O2 (Note that the ellipse-shaped contact surfaces 111 and 112 in FIG. 1 to FIG. Although drawn in the direction, the elliptical contact surfaces 111 and 112 actually appear along the peripheral surface 11a of the power roller 11). On the other hand, during a high load operation in which a large load (for example, a preset maximum rated load) is applied to the output shaft 40, the trunnion 15 and its surrounding constituent members are elastically deformed by an external force. Therefore, the contact surface 111 of the power roller 11 moves to the outer diameter side of the power roller 11 and becomes an elliptical surface having a large diameter centering on the axis O1. The contact surfaces 111 and 112 of the power roller 11 are those when a high load operation is performed at a gear ratio Low and those when a low load operation is performed at a gear ratio High. Even if changes, the position and size are almost the same.

  FIG. 2 shows the contact surface 111 and the texture processing ranges 115 and 116 on the power roller 11 side during high load operation. FIG. 4A is a two-dimensional graph showing the region of the contact surface 111, where the x-axis indicates the circumferential direction of the power roller 11, the y-axis is orthogonal to the circumferential direction, and indicates the direction along the circumferential surface 11a. ing. FIG. 4B is a graph showing the surface pressure of the contact surface 111, the horizontal axis indicates the surface pressure P, and the vertical axis is the vertical direction of the contact surface 111 (perpendicular to the circumferential direction and along the peripheral surface 11a). Direction). FIG. 3 shows a side surface of the power roller 11 subjected to texture processing. As shown in FIGS. 2 and 3, the peripheral surface 11 a of the power roller 11 is excluded from the vicinity of the position where the Hertz contact stress (surface pressure P) is maximum in the contact surface 111 during high load operation. Further, a texture process is applied to a range 115 on the outer diameter side (trunnion 15 side) of the power roller 11 and a range 116 on the inner diameter side (displacement shaft 23 side) of the power roller 11 from the vicinity range.

  In the texture processing, fine grooves and fine irregularities (for example, dimples) are formed by laser processing and have an effect of increasing the traction coefficient. In addition to laser processing, texture processing can be formed by mechanical processing such as polishing, grinding, and shot peening.

  In such a toroidal-type continuously variable transmission, even when a large shearing force is generated on the contact surface between the power roller 11 and the input / output side disks 2 and 3 during high load operation, the contact on the power roller 11 side. The surface 111 is textured on both sides except for the vicinity of the portion where the maximum surface pressure is applied. Therefore, the traction coefficient of the contact surface 111 is increased and a large traction force can be generated. Therefore, the slip of the contact surface 111 can be reduced without applying a large pressing force to the contact surface. Since a large pressing force is not necessary, the size and weight of the entire apparatus can be reduced.

  In addition, since the texture processing is not performed in the vicinity of the portion to which the maximum surface pressure is applied in the contact surface 111 during the high load operation, the traction surface is peeled or oil film is applied by applying the maximum surface pressure to the texture processing portion. It is possible to avoid a phenomenon such as cutting. Therefore, it is possible to avoid a decrease in durability of the traction surface.

  FIG. 4 shows a modification of the range 115 to be textured on the contact surface 111 on the power roller 11 side. This modification is texture processing only in the range 115 on the outer diameter side (the trunnion 15 side) of the power roller 11 from the vicinity of the position where the surface pressure P becomes maximum in the contact surface 111 on the power roller 11 side during high load operation. Is given. In this modified example, the textured portion of the power roller 11 appears on the contact surface 111 only during high load operation in which a large shear force is generated on the traction surface. And even when the position of the contact surface changes to the inner diameter side of the power roller 11 during operation from a high load to a medium load where the shearing force gradually weakens, a portion with texture processing does not appear in the maximum surface pressure portion of the contact surface. . Therefore, it is possible to reliably avoid the deterioration of the traction surface due to the texture processing during the operation from the high load to the medium load, and to reliably maintain the durability of the traction surface. In addition, the processing range can be reduced and the processing cost can be reduced.

  In the toroidal-type continuously variable transmission according to the above-described embodiment, the textured ranges 115 and 116 are applied on the basis of the position of the contact surface 111 during high load operation in which the maximum rated load is applied to the output side. Explained that no range was determined. However, when the toroidal continuously variable transmission is operated under specific conditions and the maximum load (a predetermined amount of load) is determined under these operating conditions, the contact surface during operation at the maximum load is determined. The range where the texture processing is performed and the range where the texture processing is not performed may be determined on the basis of the position.

  The present invention can be applied to various half-toroidal continuously variable transmissions such as a single cavity type and a double cavity type.

2 Input side disk 2a Inner side surface 3 Output side disk 3a Inner side surface 11 Power roller 11a Circumferential surface 40 Output shaft 111 Contact surface during high load operation 112 Contact surface 115 and 116 during low load high speed operation

Claims (4)

An input side disk and an output side disk that are supported concentrically and rotatably with their inner side surfaces facing each other, and a power roller sandwiched between the input side disk and the output side disk And an output shaft that rotates when power is transmitted from the output side disk, and the power is generated by a traction force through an oil film formed on a contact surface between the power roller, the input side disk, and the output side disk. In the toroidal type continuously variable transmission to be transmitted,
A range on the inner diameter side from the range except for a range that overlaps the vicinity of a portion where the maximum surface pressure is generated among the surface range of the power roller that becomes the contact surface during high load operation in which a predetermined amount of load is applied to the output shaft. A toroidal continuously variable transmission characterized in that texture processing is applied to one or both of the outer diameter side ranges.   The toroidal-type continuously variable transmission according to claim 1, wherein texture processing is performed only in a range on the outer diameter side.   The toroidal continuously variable transmission according to claim 1 or 2, wherein the predetermined amount of load is a predetermined maximum rated load.   The toroidal continuously variable transmission according to any one of claims 1 to 3, wherein the texture processing is processing for forming fine irregularities or fine grooves.

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