JP4894178B2 - Toroidal continuously variable transmission - Google Patents

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. 6, 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. Further, the power roller 11 (see FIG. 7) is rotatable between the inner side surfaces (concave surfaces) 2a, 2a of the input side discs 2, 2 and the inner side surfaces (concave surfaces) 3a, 3a of the output discs 3, 3. It is pinched.

  A step 2b is provided on the inner peripheral surface 2c of the input side disk 2 located on the right side in FIG. 6, 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 (the right surface in FIG. 6) 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 1d of the input shaft 1, and this disc spring 8 is a concave surface 2a, 2a, 3a of each disk 2, 2, 3, 3. , 3a and the contact surface between the peripheral surfaces 11a and 11a of the power rollers 11 and 11 are applied with a pressing force.

  As shown in FIG. 7 which is a cross-sectional view taken along the line AA in FIG. 6, both the disks 3 and 3 are sandwiched from both sides inside the casing 50 and laterally to the output side disks 3 and 3. The pair of yokes 23A and 23B is supported in the state. The pair of yokes 23A and 23B are formed in a rectangular shape by pressing or forging a metal such as steel. In order to support pivots 14 provided at both ends of the trunnion 15 to be described later in a swingable manner, circular support holes 18 are provided at the four corners of the yokes 23A and 23B, and the width direction of the yokes 23A and 23B. A circular locking hole 19 is provided at the center of the.

  The pair of yokes 23 </ b> A and 23 </ b> B are supported so as to be slightly displaceable by support posts 64 and 68 formed on portions of the inner surface of the casing 50 facing each other. These support posts 64 and 68 are provided so as to face the first cavity 221 and the second cavity 222, respectively, between the inner side surface 2a of the input side disk 2 and the inner side surface 3a of the output side disk 3. Yes.

  Therefore, the yokes 23 </ b> A and 23 </ b> B are supported by the support posts 64 and 68, and one end thereof faces the outer peripheral portion of the first cavity 221, and the other end faces the outer peripheral portion of the second cavity 222. is doing.

  Since the first and second cavities 221 and 222 have the same structure, only the first cavity 221 will be described below.

  As shown in FIG. 7, inside the casing 50, the first cavity 221 is provided with a pair of trunnions 15 and 15 that swing around a pair of pivots 14 and 14 that are twisted with respect to the input shaft 1. It has been. In addition, illustration of the input shaft 1 is abbreviate | omitted in FIG. Each trunnion 15, 15 is a pair of bent portions formed in a state in which the trunnions 15, 15 are bent at the inner side of the support plate 16 at both ends in the longitudinal direction (vertical direction in FIG. 7) of the support plate 16. Wall portions 20 and 20 are provided. 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 in the center portion of the support plate portion 16, and a base end portion (first shaft 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. In addition, each power roller 11 is rotatably supported around the tip end portion (second shaft portion) 23b of the displacement shaft 23 protruding from the inner surface of each trunnion 15, 15. 11 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, as described above, the pivot shafts 14 and 14 of the trunnions 15 and 15 are supported so as to be swingable with respect to the pair of yokes 23A and 23B and displaceable in the axial direction (vertical direction in FIG. 7). The trunnions 15 and 15 are restricted from moving in the horizontal direction by the yokes 23A and 23B. As described above, four circular support holes 18 are provided at the four corners of each of the yokes 23 </ b> A and 23 </ b> B. The pivot shafts 14 provided at both ends of the trunnion 15 are respectively provided in the support holes 18 with the radial needle bearings 30. It is supported so as to be able to swing through. Further, as described above, the circular locking hole 19 is provided in the central portion of the yokes 23A and 23B in the width direction (left-right direction in FIG. 7), and the inner peripheral surface of the locking hole 19 is spherical. Support posts 64 and 68 are internally fitted as concave surfaces. That is, the upper yoke 23A is swingably supported by the spherical post 64 supported by the casing 50 via the fixing member 52, and the lower yoke 23A is composed of the spherical post 68 and the cylinder supporting the same. 31 is supported by the upper cylinder body 61 so as to be swingable.

  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. Further, the direction in which the distal end portion 23b of each of the displacement shafts 23, 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, 4 and 4 (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.

  Further, between the outer surface of the power roller 11 and the inner surface of the support plate portion 16 of the trunnion 15, a thrust ball bearing 24 that is a thrust rolling bearing, and a thrust needle bearing, in order from the outer surface side of the power roller 11. 25. 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 the thrust ball bearings 24 is composed of a plurality of balls 26, 26, an annular retainer 27 for holding the balls 26, 26 in a freely rolling manner, and an annular outer ring 28. ing. Further, the inner ring raceway of each thrust ball bearing 24 is formed on the outer side surface (large end 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, driving rods (shaft portions extending from the pivot shaft) 29 and 29 are respectively provided at one end portions (lower end portions in FIG. 7) of the trunnions 15 and 15, and outer peripheral surfaces of intermediate portions of the driving rods 29 and 29. The drive pistons (hydraulic pistons) 33, 33 are fixedly provided. 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 of the trunnions 15 and 15.

  In the case of the toroidal continuously variable transmission configured as described above, the rotation of the drive shaft 22 is transmitted to the input side disks 2 and 2 and the input shaft 1 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. It is taken out more.

  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 displaced in directions opposite to each other. For example, the power roller 11 on the left side of FIG. 7 is displaced downward in the figure, and the power roller 11 on the right side of FIG. 7 is displaced upward in 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. As the force changes, the trunnions 15 and 15 swing 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 rotational speed 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 slightly rotate 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, bearing means for reducing axial resistance is provided between the input shaft 1 and the input side disk 2 (see, for example, Patent Document 1). In the configuration shown in FIG. 6 using the loading cam type pressing device 12, the ball spline 6 is provided as a bearing means. However, as shown in FIG. 8, the pressing device 12A is hydraulic and the input shaft 1 and the output shaft. Also in the toroidal type continuously variable transmission with the same axis, it is conceivable that a ball as shown in FIG.

Japanese Utility Model Publication No. 1-122550

  In the toroidal type continuously variable transmission, the elastic deformation of the disks 2 and 3 generated by the two-point pressing load from the power roller 11 is large. In particular, when the radially inner sides of the disks 2 and 3 are in contact with the power roller 11 (low speed side in the input disk 2), the force in the direction perpendicular to the axis at the contact point increases, and as shown in FIG. There is a possibility that a load due to deformation is applied to the bearing means (arranged with the balls) 6 disposed between the inner peripheral surface 2b and the outer peripheral surface 1e of the input shaft 1 and the surface pressure is increased. In order to reduce the surface pressure, as shown in FIGS. 11 and 12, it is necessary to increase the number of rolling elements 6b supported by the annular retainer 6a constituting the bearing means 6. There is a limit to the number of rolling elements 6b that can be arranged in the circumferential direction of 6a, and the size of the bearing means 6 must be increased.

  The present invention has been made in view of the above circumstances, and increases the number of rolling elements constituting the bearing means without increasing the size of the bearing means interposed between the input shaft and the input side disk. An object of the present invention is to provide a toroidal-type continuously variable transmission capable of achieving the above.

In order to achieve the above object, a toroidal continuously variable transmission according to claim 1 is coupled to a drive shaft that transmits a rotational force from a drive source and an input shaft that receives the rotational force from the drive shaft, and the input. An input-side disk that rotates integrally with the shaft, an output-side disk that receives the rotational force of the input-side disk at a predetermined gear ratio via a power roller provided between the input-side disk, the input shaft, and the input In a toroidal type continuously variable transmission comprising a bearing means interposed between the side disk,
The bearing means is composed of an annular retainer and a plurality of rolling elements rotatably supported by the retainer,
The rolling element is formed by cutting two surfaces of a ball on both sides in the circumferential direction of the cage into a circular arc shape, and has a substantially disk shape having convex surface portions protruding outward on both sides in the circumferential direction of the cage. The radius of curvature of the convex portion is set larger than the radius of the rolling element.

  According to the toroidal-type continuously variable transmission of the present invention, the rolling elements constituting the bearing means are formed in a substantially disc shape by removing portions on both sides in the circumferential direction of the cage. The width of the cage in the circumferential direction is reduced, and the number of rolling elements that can be supported by the annular cage is increased as compared with the conventional case. Therefore, the load distribution per rolling element can be reduced, and as a result, excessive surface pressure can be suppressed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The feature of the present invention lies in the structure of the bearing means inserted between the input shaft and the input side disk, and the other configuration and operation are the same as the conventional configuration and operation described above. Only the characteristic part of the present invention will be described, and the other parts will be simply described with the same reference numerals as in FIGS.

  1 and 2 show a first embodiment of the present invention. As shown in the figure, the bearing (bearing means) 6A of the present embodiment is inserted between the input shaft 1 and the input side disk 2 (corresponding to the ball spline 6 in FIG. 5), and has an annular shape. The holder 200 and a plurality of rolling elements 202 supported rotatably on the holder 200.

  As shown in FIG. 2A, the bearing 6 </ b> A includes the input shaft 1 and the input side disk 2 so that the rolling element 202 contacts the outer peripheral surface 1 e of the input shaft 1 and the inner peripheral surface 2 b of the input side disk 2. It is inserted between. Further, as shown in FIG. 2B, the rolling element 202 is obtained by linearly cutting two surfaces of the ball, and has approximately flat portions 202 a and 202 a on both sides in the circumferential direction of the cage 200. It has a disk shape, is supported by the cage 200 via a flat part 202a, and is connected to the input shaft 1 and the input side disk 2 via arcuate parts 202b and 202b that form the peripheral surface of the disk. Touched. Further, the rolling elements 202 adjacent to each other are arranged along the circumferential direction of the cage 200 with the flat portions 202a facing each other.

  Thus, in this embodiment, the rolling elements 202 constituting the bearing 6 </ b> A have a substantially disk shape in which portions on both sides in the circumferential direction of the ball cage 200 are removed, and flat portions 202 a are formed on both sides of the rolling elements 202. , 202a is provided, the width of the rolling element 202 in the circumferential direction of the cage 200 is reduced, and the number of rolling elements 202 that can be supported by the annular cage 200 is increased as compared with the prior art. Therefore, the load distribution per rolling element can be reduced, and as a result, excessive surface pressure can be suppressed. In addition, since the input side disk 2 and the input shaft 1 do not rotate relative to each other and slide only in the axial direction, there is no adverse effect associated with using the rolling element 202 configured as in this embodiment.

FIG. 3 is a diagram showing a modification of the first embodiment of FIGS. 1 and 2. In this example, the rolling element 202 ′ is obtained by cutting two surfaces on both sides in the circumferential direction of the ball cage 200 into a circular arc shape, and a convex surface portion 202 c protruding outward on both sides in the circumferential direction of the cage 200. , 202c, and is supported by the cage 200 via the convex surface portion 202c, and the input shaft 1 and the arcuate portions 202b, 202b forming the circumferential surface of the disc. It is brought into contact with the input side disk 2. That is, the rolling element 202 ′ is different from the rolling element 202 only in that the convex portions 202c and 202c are used instead of the flat portions 202a and 202a. Furthermore, the curvature radius _{R 2} of the convex portion 202c is the curvature of the arcuate portion 202b radius (i.e., radius of the ball) is considerably larger set than _{R 0.}

  In this modified example, the rolling element 202 ′ constituting the bearing 6 </ b> A has a substantially disk shape in which portions on both sides in the circumferential direction of the ball cage 200 are removed, and convex surface portions 202 c and 202 c are formed on both sides of the rolling element 202. Therefore, the width of the rolling element 202 ′ in the circumferential direction of the cage 200 is reduced, and the number of the rolling elements 202 that can be supported by the annular cage 200 is increased as compared with the conventional example. Therefore, the same operational effects as those of the first embodiment can be achieved.

4 and 5 show a second embodiment of the present invention. As shown in the figure, the bearing (bearing means) 6B of this embodiment also includes an annular cage 200 and a plurality of rolling elements 204 that are rotatably supported by the cage 200. Is slightly different from the first embodiment. That is, the rolling element 204 of the present embodiment has flat portions 204a, 204a supported by the cage 200 on both sides, as shown in FIG. 4B in particular, and the input shaft 1 and the input side disk therebetween. arcuate portion 204b which is contacted with 2, has the 204b, bus shape has forms a curvature radius R _1, the crowning of the so-called single arc has become decorated with roller shape. Specifically, R ₁ is set such that (D−d) / 4 ≦ R ₁ ≦ D / 2, where D is the inner diameter of the input side disk 2 and d is the outer diameter of the input shaft 1. . Therefore, according to this structure, the rolling radius of curvature of the moving object 204 can be increased, it is possible to further reduce the contact surface pressure (R ₁ is the surface pressure becomes smaller toward D / 2).

  The present invention can be applied to various half-toroidal continuously variable transmissions such as a single cavity type and a double cavity type, as well as full toroidal continuously variable transmissions without trunnions.

It is a perspective view of the bearing of the toroidal type continuously variable transmission which concerns on the 1st Embodiment of this invention. (A) is a longitudinal cross-sectional view of the bearing of FIG. 1, (b) is an expanded sectional view of the A section of (a). It is an expanded sectional view showing the modification of the 1st embodiment of the present invention. It is a perspective view of the bearing of the toroidal type continuously variable transmission which concerns on the 2nd Embodiment of this invention. (A) is a longitudinal cross-sectional view of the bearing of FIG. 3, (b) is an expanded sectional view of the B section of (a). It is sectional drawing which shows an example of the specific structure of the toroidal type continuously variable transmission conventionally known. It is sectional drawing which follows the AA line of FIG. It is sectional drawing which shows an example of the other specific structure of the toroidal type continuously variable transmission conventionally known. It is a principal part expanded sectional view of FIG. It is a figure which shows a mode that a load is loaded to a bearing by the elastic deformation of the input side disk generate | occur | produced by the 2-point pushing load from a power roller. It is a perspective view of the conventional bearing shown by FIG. It is a longitudinal cross-sectional view of the bearing of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Input shaft 2 Input side disk 4 Output side disk 11 Power roller 22 Drive shaft 6A, 6B Bearing (bearing means)
200 Cage 202a, 204a Flat part 202c, 204c Convex part 202, 204 Rolling element

Claims (1)

Power provided between the input shaft and a drive shaft that transmits the rotational force from the drive source, an input disk that is coupled to the input shaft that receives the rotational force from the drive shaft, and rotates integrally with the input shaft A toroidal-type continuously variable transmission comprising: an output-side disk that receives the rotational force of the input-side disk through a roller at a predetermined speed ratio; and bearing means interposed between the input shaft and the input-side disk. In the machine
The bearing means is composed of an annular retainer and a plurality of rolling elements rotatably supported by the retainer,
The rolling element is formed by cutting two surfaces of a ball on both sides in the circumferential direction of the cage into a circular arc shape, and has a substantially disk shape having convex surface portions protruding outward on both sides in the circumferential direction of the cage. The toroidal continuously variable transmission is characterized in that the radius of curvature of the convex portion is set larger than the radius of the rolling element.

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