JP2012117569A - Toroidal continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve a structure capable of maintaining a contact state between the circumferential face of a power roller 8b and each disk regardless of changes in an elastic deformation amount of each structural member by displacing the power roller 8b in an axial direction of each disk.SOLUTION: A support beam 34 having a cylindrical recessed face 33 is disposed in the intermediate portion of a trunnion 9b. A partially cylindrical projection portion 38 formed on the outer face of an outer ring 37 constituting a thrust ball bearing 36 that supports the power roller 8b is engaged with the cylindrical recessed face 33 of the support beam 34. The outer ring 37 and the power roller 8b are supported so as to be swing-displaceable with respect to the trunnion 9b in axial directions of the both disks in an input side and an output side.

Description

  The toroidal continuously variable transmission according to the present invention is used alone or in combination with a planetary gear type transmission as an automobile transmission or as a transmission for adjusting the operating speed of various industrial machines such as pumps. Use.

 The use of toroidal continuously variable transmissions as automotive transmissions has been described in many publications and is partly implemented and well known. FIG. 3 shows a basic configuration of a double-cavity toroidal continuously variable transmission that is currently being implemented. First, this conventional structure will be briefly described. A pair of input side disks 1a and 1b with respect to the input rotation shaft 2, each of which is a toroidal curved surface (concave arc-shaped concave surface) and corresponding to one axial side surface recited in the claims. In a state where the three and three are opposed to each other, concentric and synchronized rotation is supported freely.

  An output cylinder 5 having an output gear 4 fixed to the outer peripheral surface of the intermediate portion is supported around the intermediate portion of the input rotary shaft 2 so as to freely rotate with respect to the input rotary shaft 2. Further, output side disks 6 and 6 are supported at both ends of the output cylinder 5 so as to be rotatable in synchronization with the output cylinder 5 by spline engagement. In this state, each of the output side inner surfaces 7 and 7 of the output side disks 6 and 6, each of which is a toroidal curved surface and corresponding to one axial side surface recited in the claims, is the both input side inner side surfaces. 3 and 3 are opposed.

  Further, two power rollers 8 and 8 each having a spherical convex surface on each of the peripheral surfaces (cavities) between the input side and output side inner side surfaces 3 and 7 around the input rotation shaft 2 are provided. It is arranged. The power rollers 8 and 8 are respectively connected to the inner surfaces of the trunnions 9 and 9 via support shafts 10 and 10 whose base half and tip half are eccentric and a plurality of rolling bearings. 10 is supported in such a manner that it can be rotated about the front half of the front half and a small amount of swinging about the base half of each of the support shafts 10 and 10.

  The trunnions 9 and 9 are swingable and displaceable about the tilting shafts provided concentrically for the trunnions 9 and 9 at both ends in the length direction (front and back direction in FIG. 3). is there. The operation of swinging (tilting) each of the trunnions 9 and 9 is performed by displacing each of the trunnions 9 and 9 in the axial direction of each of the tilt shafts by a hydraulic actuator. At the time of shifting, the trunnions 9 and 9 are displaced in the axial direction of the tilt shafts by supplying and discharging pressure oil to and from the actuators. As a result, the direction of the force acting in the tangential direction of the contact portion (traction portion) between the peripheral surface of each of the power rollers 8 and 8 and each of the input side and output side inner surfaces 3 and 7 changes (side slip occurs). Therefore, the trunnions 9, 9 are oscillated and displaced about the tilt axes.

  During operation of the toroidal type continuously variable transmission as described above, one input side disk 1a is rotated by the drive shaft 11 via a loading cam type pressing device 12 (see FIG. 3). As a result, the pair of input-side disks 1a and 1b supported at both ends of the input rotation shaft 2 rotate synchronously while being pressed toward each other. Then, this rotation is transmitted to the output side disks 6 and 6 through the power rollers 8 and 8 and is taken out from the output gear 4.

  When the ratio of the rotational speeds of the input rotary shaft 2 and the output gear 4 is changed, and when the deceleration is first performed between the input rotary shaft 2 and the output gear 4, the trunnions 9, 9 are arranged as shown in FIG. The power rollers 8 and 8 are swung to the positions shown in FIG. 3 so that the peripheral surfaces of the input-side discs 1a and 1b and the output-side discs 6 and 6 It is made to contact | abut to the outer peripheral side part of the output side inner surfaces 7 and 7, respectively. On the contrary, when the speed is increased, the trunnions 9, 9 are swung in the direction opposite to that shown in FIG. 3, and the peripheral surfaces of the power rollers 8, 8 are input to the input disks 1a, 1b. It is made to contact | abut to the outer periphery side part of the side inner side surfaces 3 and 3 and the center side part of the output side inner side surfaces 7 and 7 of the said output side disks 6 and 6, respectively. An intermediate speed ratio (transmission ratio) can be obtained between the input rotary shaft 2 and the output gear 4 by setting the swing angles of the trunnions 9 and 9 to an intermediate position.

  During operation of the toroidal type continuously variable transmission as described above, the members used for power transmission, that is, the input side and output side disks 1a, 1b, 6 and the power rollers 8, 8 are It is elastically deformed based on the pressing force (thrust) generated by the pressing device 12. And along with this elastic deformation, each said disk 1a, 1b, 6 is displaced to an axial direction. Further, the pressing force generated by the pressing device 12 increases as the torque transmitted by the toroidal continuously variable transmission increases, and the amount of elastic deformation of each member increases accordingly. Accordingly, in order to properly maintain the contact state between the input and output side surfaces 3 and 7 and the peripheral surfaces of the power rollers 8 and 8 irrespective of the torque fluctuation, 8 is required to displace the disc 8 in the axial direction of the discs 1a, 1b, 6 with respect to the trunnions 9, 9. In the case of an example of the conventional structure shown in FIG. 3, the front half of each of the support shafts 10 and 10 that support the power rollers 8 and 8 is also oscillated and displaced about the base half. Thus, the power rollers 8, 8 are displaced in the axial direction.

  In the above-described conventional structure, the power rollers 8 and 8a are displaced in the axial direction of the disks 1, 1a, 1b and 6, so that the disks 1, 1a, The contact state between 1b and 6 and the peripheral surfaces of the power rollers 8 and 8 can be properly maintained. However, the structure for displacing each of the power rollers 8 and 8 in the axial direction is complicated, and parts production, parts management, and assembly work are all troublesome, and it is inevitable that costs increase.

  Therefore, in the toroidal type continuously variable transmission of Patent Document 1, each trunnion exists between a pair of tilting shafts provided concentrically at both ends, and between these tilting shafts, and at least both discs And a support beam portion having a cylindrical convex surface on the inner side surface in the radial direction. Further, the central axis of the cylindrical convex surface is parallel to the central axis of both tilting axes, and is present outside the central axis of the tilting axis in the radial direction of both disks.

  Each thrust rolling bearing is provided between the support beam portion and the outer surface of each power roller. The outer ring is provided on the support beam portion side, and is provided on the inner surface of the outer ring. A plurality of rolling elements are provided between the outer ring raceway and the inner ring raceway provided on the outer surface of the power roller.

  The outer ring swings in the axial direction of both discs with respect to each trunnion by engaging a concave portion having a partial cylindrical surface provided on the outer surface with a cylindrical convex surface of the support beam portion. The displacement is supported.

JP 2008-25821 A

  However, in the configuration of Patent Document 1, as shown in FIG. 4, when the radius of curvature r13 of the concave portion 13 of the power roller 8a is larger than the radius of curvature r14 of the cylindrical convex surface 14 of the trunnion 9a, the concave portion 13 and the cylindrical convex surface 14 are obtained. When a thrust load is applied to the thrust ball bearing 16 from the power roller 8a, the outer ring 17 may be elastically deformed as shown in FIG. 5 to reduce the efficiency. there were.

  In view of the circumstances as described above, the present invention suppresses the elastic deformation of the outer ring constituting the thrust ball bearing, ensures the durability of the thrust ball bearing, and improves the durability of the toroidal type continuously variable transmission as a whole. Invented to make it happen.

  In order to solve the above-mentioned problem, the toroidal type continuously variable transmission according to claim 1 is concentric with each other in a state in which one axial side surfaces of each of the curved surfaces each having a circular arc shape are opposed to each other. Twist position with respect to the central axis of each of the discs at a plurality of locations in the circumferential direction between the axial side surfaces of each of the discs with respect to the axial direction. A plurality of trunnions that are freely provided with oscillating displacement about the tilting shaft, and inner surfaces of these trunnions, which are rotatably supported by thrust rolling bearings, respectively, to form spherical convex surfaces. A toroidal-type continuously variable transmission having a plurality of power rollers each having a circumferential surface abutting against one axial side surface of each of the discs. The pair of tilting shafts provided between the two tilting shafts and at least the inner side surface in the radial direction of the two discs in parallel with the central axis of the two tilting shafts. Each of the thrust rolling bearings includes a support beam portion having a cylindrical concave surface having a center axis that exists outside the center axis of the tilt axis in the radial direction of the two disks. Between the outer ring and the outer surface of the power roller, the outer ring provided on the support beam portion side, the outer ring raceway provided on the inner surface of the outer ring, and the outer surface of the power roller. A plurality of rolling elements provided between the inner ring raceway and the inner ring raceway, wherein the outer ring has a partial cylindrical surface-shaped convex part provided on the outer surface and the support. Each trunnion by engaging the cylindrical concave surface of the beam Against, characterized in that it is supported to allow swinging displacement in the axial direction of both disks.

  According to the present invention, the convex portion formed on the outer surface of the outer ring constituting the thrust ball bearing is brought into contact with the cylindrical concave surface provided on the support beam portion constituting the trunnion in the circumferential direction of both surfaces. Therefore, even when a large thrust load is applied to the outer ring, the outer ring can be prevented from elastically deforming in the direction of narrowing the opening width of the convex portion. Therefore, the extent to which the distance between the outer ring raceway provided on the inner side surface of the outer ring and the inner ring raceway provided on the outer side surface of the power roller is not the same in the circumferential direction of both raceways can be suppressed. For this reason, it can prevent that the surface pressure of the rolling contact part of these both track | trucks and the rolling surface of each ball | bowl is partly excessive. As a result, it is possible to ensure the durability of the thrust ball bearing, and thus the durability of the toroidal continuously variable transmission incorporating the thrust ball bearing.

Sectional drawing of embodiment of this invention. AA sectional drawing of FIG. Sectional drawing of the conventional continuously variable transmission. The figure which shows the state before the thrust load was added to the thrust ball bearing from the power roller. The figure which shows the state after the thrust load is added to the thrust ball bearing from the power roller.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The structure and operation of the speed change mechanism are the same as those conventionally known, including the structure shown in FIG. For this reason, about the part comprised similarly to the past, illustration and description are labor-saving or simplified, and it demonstrates focusing on the characteristic part of embodiment of this invention.

  As shown in FIGS. 1 and 2, in the toroidal type continuously variable transmission according to the embodiment of the present invention, the trunnions 9b constituting the toroidal type continuously variable transmission of this example are provided concentrically at both ends. A pair of tilting shafts 15 and 15, and between these tilting shafts 15 and 15, and at least the radial direction of both the input side and output side disks 1 a, 1 b, 6 (see FIGS. 1 and 2). And a support beam portion 34 having a cylindrical concave surface 33 on the inner side (upper side in FIGS. 1 and 2) in the vertical direction. Both the tilting shafts 15 and 15 are supported by a yoke (not shown) via radial needle bearings 35 and 35 so as to be swingable. Further, as shown in FIG. 1, the central axis A of the cylindrical concave surface 33 is parallel to the central axis B of the both tilting shafts 15, 15, and more than the central axis B of the tilting shafts 15, 15. It exists outside (the lower side of FIGS. 1 and 2) with respect to the radial direction of each of the disks 1a, 1b, and 6. A partially cylindrical surface-shaped convex portion 38 is radially crossed on the outer surface of an outer ring 37 constituting a thrust ball bearing 36 provided between the support beam portion 34 and the outer surface of the power roller 8b. Is provided. Then, the convex portion 38 is engaged with the cylindrical concave surface 33 of the support beam portion 34 to support the outer ring 37 with respect to the trunnion 9b so as to be able to swing and displace in the axial direction of each disk. ing. In the case of this example, the curvature radius of the cross-sectional shape of the convex portion 38 and the curvature radius of the cross-sectional shape of the cylindrical concave surface 33 are made to coincide with each other, and the convex portion 38 and the cylindrical concave surface 33 are directly connected. It is in contact.

  In the case of this example, a support shaft 10b is fixed to the central portion of the inner surface of the outer ring 37, and the power roller 8b is mounted around the support shaft 10b as a radial needle bearing. 39 is rotatably supported via 39.

According to the toroidal type continuously variable transmission of this example configured as described above, the power roller 8b is displaced in the axial direction of each of the disks 1a, 1b, 6 to change the amount of elastic deformation of each component. Regardless, the structure that can properly maintain the contact state between the peripheral surface of the power roller 8b and the disks 1a, 1b, and 6 can be configured simply and at low cost. That is, during operation of the toroidal type continuously variable transmission, the power rollers 8b are connected to the disks 1a, 1b, 6 and the power rollers 8b based on the elastic deformation of the power rollers 8b.
When it is necessary to displace in the axial directions of a 1, 1 b, 6, the outer ring 37 of the thrust ball bearing 36 that rotatably supports each of the power rollers 8 b is in the form of a partial cylindrical surface provided on the outer surface. While the abutting surface of the convex portion 38 and the cylindrical concave surface 33 of the support beam portion 34 is slid, it is oscillated and displaced about the central axis A of the cylindrical concave surface 33. Based on this oscillating displacement, a portion of the peripheral surface of each power roller 8b that is in rolling contact with one axial side surface of each disk 1a, 1b, 6 is the axial direction of each disk 1a, 1b, 6. To maintain the above contact state properly. As described above, the central axis A of the cylindrical concave surface 33 is more discreet than the central axes B of the tilting shafts 15 and 15 that become the swing centers of the trunnions 9b during the shifting operation. It exists outside in the radial direction. Accordingly, the rocking radius of the rocking displacement centered on the engaging portion is larger than the rocking radius in the shifting operation, and the gear ratio between the input side disks 1a and 1b and the output side disk 6 is large. Has little impact on the fluctuations (it can be neglected or easily corrected).
In this way, the processing of the convex portion 38 and the cylindrical concave surface 33, which are required for maintaining the contact state properly, is easy, and no special parts are required.

  The present invention can be used as a transmission for automobiles and various industrial machines.

1, 1a, 1b Input side disk 2 Input rotation shaft 3 Input side inner surface 4 Output gear 5 Output cylinder 6 Output side disk 7 Output side inner surface 8, 8a, 8b Power roller 9, 9a, 9b Trunnion 10, 10b Support shaft DESCRIPTION OF SYMBOLS 11 Drive shaft 12 Pressing device 13 Concave part 14 Cylindrical convex surface 15 Inclination shaft 16 Thrust ball bearing 17 Outer ring 33 Cylindrical concave surface 34 Support beam part 35 Radial needle bearing 36 Thrust ball bearing 37 Outer ring 38 Convex part 39 Radial needle bearing

Claims (1)

At least one pair of discs that are concentric with each other in a state in which each side surface in the shape of a circular arc is opposed to each other and concentrically supported so as to be freely rotatable relative to each other. A plurality of trunnions provided at a plurality of locations in the circumferential direction between the side surfaces in the axial direction at various positions freely swinging about the tilting shaft that is twisted with respect to the central axis of each disk. A plurality of power rollers that are rotatably supported on the inner side surfaces of these trunnions via respective thrust rolling bearings and have spherical peripheral surfaces that are in contact with the axial side surfaces of the two discs, respectively. In a toroidal type continuously variable transmission equipped with
Each trunnion exists between the pair of tilting shafts concentrically provided at both ends and between the two tilting shafts, and at least the inner side surfaces in the radial direction of the two disks A support beam portion having a cylindrical concave surface having a central axis that is parallel to the central axis of the tilting axis and is present outside the central axis of the tilting axis with respect to the radial direction of the two disks. Each thrust rolling bearing is provided between the support beam portion and the outer surface of each power roller, and is provided on the outer ring provided on the support beam portion side and on the inner side surface of the outer ring. A plurality of rolling elements provided between the outer ring raceway and the inner ring raceway provided on the outer side surface of the power roller, the outer ring provided on the outer side surface. A partial cylindrical surface convex portion and a cylindrical concave surface of the support beam portion; To the trunnions by which engaged, toroidal type continuously variable transmission, characterized in that it is supported for swinging displacement in the axial direction of both disks.

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