Toroidal type non-stage transmission

Abstract

To provide a toroidal type non-stage transmission which can inhibit wear of a wear concerned portion caused by a skew force.SOLUTION: A toroidal type non-stage transmission includes: a shaft 1A; first discs 3 and second discs 2 which are provided in the shaft 1A concentrically with each other with their inner surfaces facing each other, the first discs being configured to rotate integrally with the shaft 1A, the second discs being configured to rotate relative to the shaft 1A; power rollers 11 each of which is sandwiched between the discs; and bearings 70 each of which is provided between the shaft 1A and the second disc 2. The bearing 70 includes: a plurality of spherical rolling elements 71 disposed at predetermined intervals in a circumferential direction of the shaft 1A; and a retainer 72 which retains the rolling elements 71 in a rollable manner.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a toroidal type continuously variable transmission that can be used in generators for automobiles and aircraft, or transmissions for various industrial machines, etc. [Background technology]

[0002] For example, a double-cavity toroidal type continuously variable transmission used as an automobile transmission is configured as shown in Figures 12 and 13. As shown in Figure 12, an input shaft 1 is rotatably supported inside a casing 49, and two input side discs 2, 2 and two output side discs 3, 3 are attached to the outer periphery of this input shaft 1. An output gear (transmission gear) 4 is rotatably supported on the outer periphery of a middle part of the input shaft 1. The output side discs 3, 3 are connected to cylindrical flange portions (sleeves) 4a, 4a provided in the center of this output gear 4 by spline coupling. The input shaft 1 is rotated by a drive shaft 22 via a loading cam type pressing device 12 provided between the input side disc 2 located on the left side in Fig. 12 and a cam plate (loading cam) 7. The output gear 4 is supported in a casing 49 via a partition wall 13 formed by joining two members, which allows the output gear 4 to rotate about the axis O of the input shaft 1 while preventing displacement in the direction of the axis O.

[0003] The output side discs 3, 3 are supported rotatably about the axis O of the input shaft 1 by needle bearings 5, 5 interposed between them and the input shaft 1. The input side disc 2 on the left side in FIG. 12 is supported on the input shaft 1 via a ball spline 6, and the input side disc 2 on the right side in FIG. 12 is spline-connected to the input shaft 1, so that these input side discs 2 rotate together with the input shaft 1. Power rollers 11 (see FIG. 13) are rotatably sandwiched between inner surfaces (concave surfaces; also called traction surfaces) 2a, 2a of the input side discs 2, 2 and inner surfaces (concave surfaces; also called traction surfaces) 3a, 3a of the output discs 3, 3.

[0004] A step portion 2b is provided on the inner peripheral surface (inner diameter surface) 2c of the input side disk 2 located on the right side in Fig. 12, and a step portion 1b provided on the outer peripheral surface 1a of the input shaft 1 abuts against this step portion 2b, and the back surface (right surface in Fig. 12) of the input side disk 2 abuts against a loading nut 9 screwed into a threaded portion formed on the outer peripheral surface of the input shaft 1. This substantially prevents the input side disk 2 from being displaced in the direction of the axis O relative to the input shaft 1. In addition, 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 applies a pressing force (preload) to the abutting portion between the concave surfaces 2a, 2a, 3a, 3a of the disks 2, 2, 3, 3 and the peripheral surfaces 11a, 11a of the power rollers 11, 11.

[0005] FIG. 13 is a cross-sectional view taken along line AA in FIG. 12. As shown in FIG. 13, a pair of trunnions 15, 15 are provided inside the casing 49, which swing about a pair of pivots 14, 14 that are in a twisted position relative to the input shaft 1. Note that the input shaft 1 is not shown in FIG. 13. Each trunnion 15, 15 has a pair of bent wall portions 20, 20 formed at both ends in the longitudinal direction (vertical direction in FIG. 13) of the support plate portion 16, in a state of bending toward the inner surface side of the support plate portion 16. The bent wall portions 20, 20 form a concave pocket portion P in each trunnion 15, 15 for accommodating the power roller 11. In addition, the pivots 14, 14 are provided concentrically with each other on the outer surfaces of the bent wall portions 20, 20.

[0006] A circular hole 21 is formed in the center of the support plate portion 16, and a base end portion 23a of a displacement shaft 23 is supported in this circular hole 21. The inclination angle of the displacement shaft 23 supported in the center of each of the trunnions 15 can be adjusted by swinging each of the trunnions 15 about each of the pivots 14. The power rollers 11 are rotatably supported around the tip portion 23b of the displacement shaft 23 protruding from the inner surface of each of the trunnions 15, and each of the power rollers 11 is sandwiched between each of the input side disks 2 and each of the output side disks 3. The base end portion 23a and the tip portion 23b of each of the displacement shafts 23 are eccentric to each other.

[0007] The pivots 14, 14 of the trunnions 15, 15 are supported by a pair of yokes 23A, 23B so as to be swingable and displaceable in the axial direction (up and down direction in FIG. 13), and the horizontal movement of the trunnions 15, 15 is restricted by the yokes 23A, 23B. The yokes 23A, 23B are formed into a rectangular shape by pressing or forging a metal such as steel. Four circular support holes 18 are provided at the four corners of the yokes 23A, 23B, and the pivots 14 provided at both ends of the trunnions 15 are supported swingably in the support holes 18 via radial needle bearings 30. The yokes 23A, 23B are provided at the center in the width direction (left and right direction in FIG. 13) with circular locking holes 19, and the inner peripheral surface of the locking holes 19 is a cylindrical surface, into which the spherical posts 64, 68 are fitted. That is, the upper yoke 23A is supported so as to be freely swingable by a spherical post 64 which is supported on the casing 49 via a fixed member 52, and the lower yoke 23B is supported so as to be freely swingable by a spherical post 68 and the upper cylinder body 56 of the drive cylinder 31 which supports it.

[0008] The displacement shafts 23, 23 provided on each trunnion 15, 15 are provided at positions 180 degrees opposite to each other with respect to the input shaft 1. The direction in which the tip end 23b of each of these displacement shafts 23, 23 is eccentric with respect to the base end 23a is the same direction as the rotation direction of both disks 2, 2, 3, 3 (upside down direction in FIG. 13). The eccentric direction is approximately perpendicular to the arrangement direction of the input shaft 1. Therefore, each power roller 11, 11 is supported so as to be slightly displaceable 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 based on the thrust load generated by the pressing device 12, this displacement is absorbed without applying excessive force to each component.

[0009] 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 (thrust bearing) 24, which is a thrust rolling bearing, and a thrust needle bearing 25 are provided in this order from the outer surface side of the power roller 11. Of these, the thrust ball bearing 24 supports the thrust load applied to each power roller 11 while allowing each power roller 11 to rotate. Each thrust ball bearing 24 is composed of a plurality of balls (hereinafter referred to as rolling elements) 26, 26, an annular cage 27 that holds each of the rolling elements 26, 26 so that they can roll freely, and an annular outer ring 28. The inner ring raceway of each thrust ball bearing 24 is formed on the outer surface (large end surface) of each power roller 11, and the outer ring raceway is formed on the inner surface of each outer ring 28.

[0010] In addition, 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 thrust needle bearing 25 supports the thrust load applied from the power rollers 11 to each outer ring 28, while allowing the power rollers 11 and the outer ring 28 to swing around the base end portion 23a of each displacement shaft 23.

[0011] Furthermore, one end of each trunnion 15 (the lower end in FIG. 13) is provided with a drive rod (trunnion shaft) 29, and a drive piston (hydraulic piston) 33 is fixed to the outer circumferential surface of the middle part of each drive rod 29. Each of these drive pistons 33 is oil-tightly fitted into a drive cylinder 31 formed by an upper cylinder body 56 and a lower cylinder body 57. Each of these drive pistons 33 and the drive cylinder 31 constitutes a drive unit 32 that displaces each of the trunnions 15 in the axial direction of the pivots 14 of the trunnions 15.

[0012] In the case of a toroidal type continuously variable transmission configured in this manner, the rotation of the input shaft 1 is transmitted to the input side discs 2, 2 via a pressing device 12. The rotation of these input side discs 2, 2 is then transmitted to the output side discs 3, 3 via a pair of power rollers 11, 11, and the rotation of each of the output side discs 3, 3 is further taken out by the output gear 4.

[0013] 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. With the displacement of each of the drive pistons 33, 33, the pair of trunnions 15, 15 are displaced in opposite directions. For example, the power roller 11 on the left side of Fig. 13 is displaced downward in the same figure, and the power roller 11 on the right side of the same figure is displaced upward in the same figure. As a result, the direction of the tangential force acting on the contact portions between the peripheral surfaces 11a, 11a of the power rollers 11, 11 and the inner surfaces 2a, 2a, 3a, 3a of the input side disks 2, 2 and the output side disks 3, 3 changes. Then, with the change in the direction of the force, the trunnions 15, 15 swing (tilt) in opposite directions to each other about the pivots 14, 14 pivoted to the yokes 23A, 23B.

[0014] As a result, the contact position between the circumferential surface 11a, 11a of each power roller 11, 11 and each inner surface 2a, 3a changes, and the rotation speed ratio between the input shaft 1 and the output gear 4 changes. In addition, when the torque transmitted between the input shaft 1 and the output gear 4 fluctuates and the elastic deformation amount of each component changes, each power roller 11, 11 and the outer rings 28, 28 attached to each power roller 11, 11 rotate slightly around the base end portion 23a, 23a of each displacement shaft 23, 23. Since the thrust needle bearings 25, 25 are present between the outer surface of each outer ring 28, 28 and the inner surface of the support plate portion 16 constituting each trunnion 15, 15, the rotation is performed smoothly. Therefore, as described above, a small force is required to change the inclination angle of each displacement shaft 23, 23. [Prior art documents] [Patent documents]

[0015] [Patent Document 1] JP 2004-347047 A Summary of the Invention [Problem to be solved by the invention]

[0016] In a toroidal type continuously variable transmission, a roller bearing or a cage and roller is placed between the disk (input disk or output disk) and the shaft, so that the disk is rotatably supported by the shaft. The disk and the shaft rotate in opposite directions, and the bearing between them must support the relative rotation. In a toroidal type continuously variable transmission for aircraft, which is used at high speeds, the relative rotation speed of the bearing is up to about 30,000 rpm, and if the bearing retainer comes into contact with a mating part (such as a snap ring) that supports the axial position, there is a concern that it may cause seizure or wear of the retainer, which may ultimately lead to damage of the retainer or snap ring.

[0017] If the bearing retainer is damaged, the vibration of the supporting disk and shaft will increase, causing the toroidal type continuously variable transmission to become out of sync and making it impossible to transmit power. In addition, when the retainer is damaged, it may impact surrounding parts, causing damage to the disk and shaft. Furthermore, if the retaining ring of a bearing breaks, the bearing will move axially, causing the rollers of the bearing to roll in places other than the intended raceway, raising the concern that this could result in premature failure of the bearing. When a radial load is applied to a cylindrical roller bearing, if it is tilted (the roller axis is tilted with respect to the axis that supports the disk) relative to the mating surface (the outer diameter surface of the shaft or the inner diameter surface of the disk), a skew force (axial load) is generated. This skew force may cause wear at the axial contact points of the cylindrical roller bearing. One example of a wear concern is the contact part of the retaining ring with which the cylindrical roller bearing comes into contact. The material and heat treatment of the retaining ring have restrictions on the surface hardness in order to satisfy the function of the retaining ring. For this reason, if the surface hardness of the retaining ring is low relative to the cylindrical roller bearing, there is a concern that wear may occur at the contact point of the retaining ring.

[0018] 14, retainer 62 of cylindrical roller bearing 60 is supported in the axial direction by shim 63 and retaining ring 64. If a skew force occurs in such a cylindrical roller bearing 60, there is a concern that wear will occur in the areas where rollers 61 contact retainer 62, where retainer 62 contacts shim 63, where shim 63 contacts retaining ring 64, where retaining ring 64 contacts fitting groove 1e of shaft 1, and so on.

[0019] The present invention has been made in consideration of the above circumstances, and has an object to provide a toroidal type continuously variable transmission that can suppress wear in areas susceptible to wear caused by skew forces. [Means for solving the problem]

[0020] In order to achieve the above object, the toroidal type continuously variable transmission of the present invention comprises a shaft, a first disk and a second disk rotatably mounted on the shaft concentrically with each other and integrally with the shaft with their inner surfaces facing each other, a power roller sandwiched between the first disk and the second disk, and a bearing mounted between the shaft and the second disk, The bearing is characterized by comprising a plurality of spherical rolling elements arranged at predetermined intervals in the circumferential direction of the shaft, and a cage that holds the plurality of rolling elements so that they can roll.

[0021] In the present invention, the bearing provided between the shaft and the second disk includes a plurality of spherical rolling elements arranged at a predetermined interval around the shaft, and a cage that holds the plurality of rolling elements so that they can roll, so that even if a radial load is applied to the bearing, the bearing does not generate a skew force (axial load) like a cylindrical roller bearing. Therefore, wear of parts at risk of wear due to skew force can be suppressed.

[0022] In the above-described configuration of the present invention, a radial gap between the inner diameter surface of the second disc and the rolling elements may be larger than a radial deformation amount of the inner diameter surface of the second disc.

[0023] With this configuration, the radial gap between the inner diameter surface of the second disc and the rolling element is larger than the amount of radial deformation of the inner diameter surface of the second disc. Therefore, even if deformation occurs in the second disc while the second disc is rotating and radial deformation occurs in the inner diameter surface of the second disc as a result, excessive radial loads can be prevented from being input to the bearing.

[0024] In the above-mentioned configuration of the present invention, a bearing groove in which the rolling elements roll may be provided on an outer diameter surface of the shaft or an inner diameter surface of the second disk.

[0025] According to this configuration, since the bearing groove is provided on the outer diameter surface of the shaft or the inner diameter surface of the second disk, the thrust load can be supported by the bearing, and therefore a restricting member such as a snap ring that restricts the axial movement of the bearing is not required.

[0026] In the above-described configuration of the present invention, the holding portion may include a holding portion into which the rolling element can be inserted from a radial direction and which can hold the inserted rolling element.

[0027] With this configuration, the retaining portion can insert the rolling elements from the radial direction and retain the inserted rolling elements, thereby improving the assembly of the bearing and enabling the rolling elements to be retained so as not to deviate from the bearing groove.

[0028] In the above-described configuration of the present invention, the cage may include a lubricant introduction portion that introduces lubricant into the bearing groove.

[0029] With this configuration, since the retainer is equipped with a lubricating oil inlet portion, a lubricating oil supply hole for supplying lubricating oil can be provided at a location other than the bearing groove, and an oil film can be secured in the bearing groove without compromising durability. Effect of the Invention

[0030] According to the present invention, it is possible to suppress wear in areas susceptible to wear caused by skew forces. [Brief description of the drawings]

[0031] [Figure 1] 1 is a cross-sectional view showing an overall outline of a toroidal type continuously variable transmission according to a first embodiment of the present invention. [Diagram 2] FIG. [Diagram 3] FIG. [Figure 4] 6 is a schematic diagram for explaining the radial gap of the bearing and the amount of deformation of the inner diameter surface of the second disk according to the first embodiment. FIG. [Diagram 5]FIG. 11 is an enlarged cross-sectional view of a main portion of a second embodiment of the present invention. [Figure 6] FIG. [Figure 7] FIG. 4 is a side view showing a main part of the output shaft of the first embodiment. [Figure 8] FIG. 11 is a schematic diagram for explaining a state in which the rolling element is held by the holding portion according to the first embodiment. [Figure 9] FIG. 11 is an enlarged cross-sectional view of a main portion of a third embodiment of the present invention. [Figure 10] FIG. 10 is an enlarged cross-sectional view of a main portion of a fourth embodiment of the present invention. [Figure 11] FIG. 10 is an enlarged cross-sectional view of a main portion of a fifth embodiment of the present invention. [Figure 12] FIG. 1 is a cross-sectional view showing an example of a conventional toroidal type continuously variable transmission. [Figure 13] 13 is a cross-sectional view taken along the line AA in FIG. 12. [Figure 14] FIG. 1 is an enlarged cross-sectional view of a main portion of an example of a conventional toroidal type continuously variable transmission for aircraft. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. (First embodiment) The toroidal type continuously variable transmission of this embodiment is a transmission used in an aircraft generator, and changes the rotation speed of the aircraft engine, which varies, to a constant rotation speed and outputs the rotation speed to the generator. FIG. 1 is a cross-sectional view showing an outline of the entire toroidal type continuously variable transmission according to the first embodiment, FIG. 2 is a cross-sectional view of a main part of the same, and FIG. 3 is an enlarged cross-sectional view of the main part in FIG. In the conventional technology shown in Fig. 12 and Fig. 13, the output side disk 3 is rotatably supported by the input shaft 1 via the bearing 5. In the present embodiment, the input side disk 2 is rotatably supported by the output shaft 1A via the bearing 70. However, the toroidal type continuously variable transmission of the present embodiment and the conventional toroidal type continuously variable transmission have the same configurations as each other, such as the power roller 11 sandwiched between the input side disk 2 and the output side disk 3, and the pressing device 12 that presses one of the input side disk 2 and the output side disk 3, the disk 2(3), toward the other disk 3(2), and the like, and therefore the description thereof will be omitted. Also, hatching is omitted in Fig. 1.

[0033] As described above, the toroidal type continuously variable transmission of this embodiment is a double-cavity half-toroidal type continuously variable transmission for an aircraft (generator), in which an input side disc (second disc) 2 and an output side disc (first disc) 3 arranged in one cavity are attached around an output shaft (shaft) 1A, and an input side disc (second disc) 2 and an output side disc (first disc) 3 arranged in the other cavity are attached around the output shaft (shaft) 1A. The input side disc 2 has a shaft hole 2A in the radial center that has a circular cross section and extends in the axial direction, and the output shaft 1A is inserted through this shaft hole 2A. One end of the shaft hole 2A opens on the small end face side of the input side disc 2 (the right side in the axial direction in Fig. 2), and the other end opens on the large end face side of the input side disc 2 (the left side in the axial direction in Fig. 2).

[0034] 1, the output side disc 3 is provided so as to be rotatable integrally with the output shaft 1A, and the input side disc 2 is provided so as to be rotatable relative to the output shaft 1A via a bearing 70. A power roller 11 is provided between the input side disc 2 and the output side disc 3, and the power roller 11 is sandwiched between the two discs 2, 3. In this embodiment, the output side disk 3 is pressed against the input side disk 2 by a pressing device 12.

[0035] 1, an input gear 40 is provided between the pair of input side discs 2, 2. For example, a rotational force from a rotating shaft of a turbine of an engine is transmitted to the input gear 40 via gears or the like. As shown in Fig. 2, the input gear 40 includes a gear portion 41 disposed on the outside (outside in the axial direction) of the input side disc 2, and a cylindrical sleeve 42 provided at the right end of the radial center side of the gear portion 41 (the output shaft 1A side in Fig. 2). The sleeve 42 is disposed coaxially with the axial hole 2A of the input side disc 2, and approximately half of the tip side of the sleeve 42 is inserted into the axial hole 2A. As shown in Fig. 1, a sleeve 42 similar to the sleeve 42 is provided symmetrically at the left end of the radial center side of the gear portion 41, and the sleeve 42 is similarly inserted into the axial hole 2A of the input side disc 2 provided in the other cavity disposed on the left side of the gear portion 41.

[0036] As shown in FIG. 2, the outer diameter surface of the tip of the sleeve 42 is provided with an outer diameter side spline portion 45a having a radially uneven shape that extends (continuously) along the circumferential direction and also extends in the axial direction. On the other hand, an inner diameter side spline portion 45b having a radially uneven shape extending (continuously) along the circumferential direction and extending in the axial direction is provided on an inner diameter surface of the shaft hole 2A of the input side disk 2 that faces the outer diameter side spline portion 45a in the radial direction. The inner diameter side spline portion 45b and the outer diameter side spline portion 45a have approximately the same length in the axial direction. Then, by spline engagement between the inner diameter side spline portion 45b and the outer diameter side spline portion 45a, the rotation of the input gear 40 is transmitted to the input side disc 2 via the sleeve 42, and the rotation of the input side disc 2 is transmitted to the output shaft 1A via the power rollers 11 and the output side disc 3.

[0037] 1 to 3, the bearing 70 is provided between the outer diameter surface 1m of the output shaft 1A and the inner diameter surface 2m of the input side disc 2, and rotatably supports the input side disc 2. The outer diameter surface 1m is a cylindrical surface, and the inner diameter surface 2m is a cylindrical surface that is coaxial with the outer diameter surface 1m and has a larger diameter than the outer diameter surface 1m.

[0038] The bearing 70 includes a plurality of spherical rolling elements 71 arranged at predetermined intervals in the circumferential direction of the output shaft 1A, and a retainer 72 that rotatably holds the plurality of rolling elements 71. The retainer 72 is formed in a circular ring shape and is arranged coaxially with the output shaft 1A. The retainer 72 is formed with a plurality of retaining holes 72a arranged at predetermined intervals in the circumferential direction, and the rolling elements 71 that roll between the output shaft 1A and the input side disk 2 are inserted into each retaining hole 72a and held so as to be able to roll. The retainer 72 is sandwiched between a pair of left and right shims 73, 73 (left and right axial pair), with a retaining ring 74 abutting against the right side surface of the shim 73 on the right axial side, and a retaining ring 74 abutting against the left side surface of the shim 73 on the left axial side. These retaining rings 74, 74 are fitted into retaining ring grooves 74a, 74a formed along the circumferential direction on the outer diameter surface of the output shaft 1A. Therefore, the bearing 70 is positioned in the axial direction by the retaining rings 74, 74, and movement in the axial direction is restricted.

[0039] Thus, according to this embodiment, the bearing 70 provided between the output shaft 1A and the second disk 2 includes a plurality of spherical rolling elements 71 arranged at predetermined intervals in the circumferential direction of the output shaft 1A, and a cage 72 that rotatably holds the plurality of rolling elements 71. Therefore, even if a radial load is generated in the bearing 70, a skew force (axial load) like that of a cylindrical roller bearing is not generated in the bearing 70. Therefore, wear of parts at risk of wear due to a skew force can be suppressed.

[0040] 4, in this embodiment, the radial gap S1 between the inner diameter surface 2m of the second disk 2 and the rolling element 71 is larger than the radial deformation amount S2 of the inner diameter surface 2m of the second disk 2. Note that the gap S1 and the deformation amount S2 are the gap and the deformation amount on one radial side of the second disk 2, and a similar gap S1 and deformation amount S2 are provided on the other side.

[0041] That is, the second disk 2 is deformed by being pressed by the power roller 11 while rotating around its axis, and accordingly, the circular inner diameter surface 2m before deformation becomes elliptical after deformation. That is, the inner diameter surface 2m after deformation is deformed into an elliptical cross section with the long axis in the left-right direction and the short axis in the up-down direction in FIG. 4. The length in the short axis direction of the inner diameter surface 2m with an elliptical cross section becomes shorter than the diameter of the circular inner diameter surface 2m before deformation, and the length in the long axis direction of the inner diameter surface 2m with an elliptical cross section becomes longer than the diameter of the circular inner diameter surface 2m before deformation. For this reason, in this embodiment, the inner diameter (diameter) of the inner diameter surface 2m of the second disk 2 is set so that the radial gap S1 between the inner diameter surface 2m of the second disk 2 before deformation and the rolling element 71 is larger than the radial deformation amount S2 of the inner diameter surface 2m of the second disk 2 before and after deformation. This makes it possible to prevent an excessive radial load from acting on the bearing 70 when the second disk 2 deforms.

[0042] Second Embodiment 5 to 8 are enlarged cross-sectional views of the main parts of a toroidal type continuously variable transmission according to a second embodiment. The second embodiment shown in Figs. 5 to 8 differs from the first embodiment shown in Figs. 1 to 4 in that the inner diameter surface 2m of the second disk 2 is provided with a bearing groove in which the rolling elements 71 of the bearing 70 roll, and in the structure of the cage. These structures will be described below, and the same structures as those in the first embodiment may be given the same reference numerals and their description may be omitted. Note that the structures other than the main parts shown in Figs. 5 to 8 are the same as those in the first embodiment, and therefore will not be illustrated.

[0043] In this embodiment, as shown in FIG. 5, a bearing 70 includes a plurality of spherical rolling elements 71 and a cage 82 that holds the plurality of rolling elements 71 so that they can roll. Further, a bearing groove 71a in which the rolling elements 71 of the bearing 70 roll is provided on the outer diameter surface 1m of the output shaft 1A. The bearing groove 71a is formed to have an arc-shaped cross section, and the radius of curvature of the bearing groove 71 is larger than the radius of curvature of the rolling elements 71. Such a bearing groove 71a may be formed on the inner diameter surface 2m of the second disk 2 instead of on the outer diameter surface 1m of the output shaft 1A.

[0044] In this embodiment, as shown in Figs. 5 to 8, the cage 82 includes holding portions 82a into which the spherical rolling elements 71 can be inserted from the radial direction and into which the inserted rolling elements can be held. That is, the cage 82 is formed in a circular ring shape obtained by axially dividing the cage 72 of the first embodiment in half, and is provided with a retaining portion 82a on one axial end face (the right end face in Figs. 5 to 8). The cage 82 is formed from, for example, PEEK resin or brass. PEEK resin is a super engineering plastic, and is a thermoplastic resin that is comprehensively excellent in heat resistance, mechanical properties, chemical resistance, electrical properties, etc.

[0045] A plurality of holding portions 82a are formed at predetermined intervals in the circumferential direction of the cage 82, and are formed in an arc-shaped cross section capable of holding the rolling elements 71. As shown in Fig. 8, the holding portion 82a having an arc-shaped cross section has claw portions 82b at both ends. The claw portions 82b, 82b protrude from the left half of the rolling elements 71 with respect to the Y axis to the right along the outer circumferential surface of the rolling elements 71, thereby restricting deviation of the rolling elements 71 in the axial direction (to the right of the X axis in Fig. 8). The X axis is an axis parallel to the output shaft 1A, and the Y axis passes through the center of the rolling elements 71 and is perpendicular to the X axis.

[0046] To insert the rolling element 71 into the retaining portion 82a, it is inserted from the radial direction of the cage 82 as shown by arrow A in Fig. 6. The retaining portion 82a is open in the radial direction to allow the rolling element 71 to be inserted, and a smooth R surface is formed on the edge of the opening of the retaining portion 82a to facilitate the insertion of the rolling element 71. Therefore, when the rolling element 71 is inserted into the retaining portion 82a from the direction of arrow A, the retaining portion 82a, which has an arc-shaped cross section, is pressed by the rolling element 71 and elastically expands radially outward, and the rolling element 71 fits into the retaining portion 82a, thereby being retained by the retaining portion 82a.

[0047] According to this embodiment, in addition to the same effects as those of the first embodiment, the following effects can be obtained. That is, since the bearing groove 71a in which the rolling elements 71 roll is provided on the outer diameter surface 1m of the output shaft 1A, the thrust load can be supported by the bearing 70. Therefore, there is no need for restricting members such as the shim 73 and the retaining ring 74 that restrict the axial movement of the bearing 70. In addition, the retaining portion 82a is provided with a retaining portion 82a into which the rolling element 71 can be inserted from the radial direction and which can retain the inserted rolling element 71, thereby improving the assembly of the bearing 70 and enabling the rolling element 71 to be retained so as not to deviate from the bearing groove 71a.

[0048] (Third embodiment) Fig. 9 shows a third embodiment and is an enlarged cross-sectional view of a main part of a toroidal type continuously variable transmission. The third embodiment shown in Fig. 9 differs from the second embodiment shown in Figs. 5 to 8 in the configuration of the cage, and therefore this configuration will be described below, and the same components as those in the second embodiment will be given the same reference numerals and their description may be omitted. Note that the configuration other than the main parts shown in Fig. 9 is the same as that of the first embodiment, and therefore will not be shown.

[0049] In this embodiment, as shown in FIG. 9, a bearing 70 includes a plurality of spherical rolling elements 71 and a cage 83 that holds the plurality of rolling elements 71 so that they can roll. In this embodiment, the cage 83 is formed in a circular ring shape, and includes a holding portion 83a into which the spherical rolling elements 71 can be inserted from the radial direction and which can hold the inserted rolling elements. The cage 83 is made of, for example, PEEK resin or brass. Further, a plurality of retaining portions 83a are formed at predetermined intervals in the circumferential direction of the cage 83, and are formed in an arc-shaped cross section capable of retaining the rolling elements 71. The retaining portions 83a are configured similarly to the retaining portions 82a of the second embodiment, and the rolling elements 71 inserted into the retaining portions 83a are restricted from axially escaping by the retaining portions 83a. To insert the rolling elements 71 into the retaining portions 83a, they are inserted from the radial direction of the cage 83, similarly to the second embodiment.

[0050] In this embodiment, the cage 83 is provided with a lubricant introduction portion 83b that introduces lubricant into the bearing groove 71a. That is, a recess 83b serving as a lubricant introduction portion 83b is formed in the inner diameter portion of the retainer 83. The recess (lubricant introduction portion) 83b is formed by cutting out the inner diameter portion of the retainer 83 along the circumferential direction to have a substantially triangular cross section, and is disposed in communication with one edge portion (the edge portion closer to the retainer 83 side) of the bearing groove 71a, and has an inclined surface 83c that is inclined in an arc shape or linear shape facing the one edge portion.

[0051] Furthermore, the output shaft 1A is formed with a lubricant supply hole 87 for supplying lubricant to the lubricant introduction portion 83b, and the opening of this lubricant supply hole 87 is disposed on the outer diameter surface of the output shaft 1A facing the lubricant introduction portion 83b. Therefore, the lubricant supplied from the lubricant supply hole 87 to the lubricant introduction portion 83b fills the lubricant introduction portion 83b, and then hits the inclined surface 83c and is introduced from one edge of the bearing groove 71a into the transfer surface of the bearing groove 71a.

[0052] Therefore, according to this embodiment, because the cage 83 is provided with the lubricant introduction portion 83b, the lubricant supply hole 87 can be provided at a location other than the bearing groove 71a, and an oil film can be secured in the bearing groove 71a without impairing durability. In other words, if a lubricant supply hole is formed in the bearing groove 71a, which is the transfer surface, stress concentration may occur at and near the lubricant supply hole, impairing durability, but in this embodiment, no lubricant supply hole is formed in the bearing groove 71a, so durability is not impaired. Of course, in this embodiment, the same effects as in the second embodiment can be obtained.

[0053] (Fourth embodiment) Fig. 10 shows a fourth embodiment and is an enlarged cross-sectional view of a main part of a toroidal type continuously variable transmission. The fourth embodiment shown in Fig. 10 differs from the second embodiment shown in Figs. 5 to 8 in the configuration of the bearing groove, and therefore this configuration will be described below, and the same components as those in the second embodiment will be given the same reference numerals and their description may be omitted. Note that the configuration other than the main parts shown in Fig. 10 is the same as that of the first embodiment, and therefore will not be shown.

[0054] In this embodiment, as shown in FIG. 10, a bearing 70 includes a plurality of spherical rolling elements 71 and a cage 85 that holds the plurality of rolling elements 71 so that they can roll. The cage 85 is formed in a circular ring shape, and includes a holding portion 85a into which the spherical rolling elements 71 can be inserted from the radial direction and which can hold the inserted rolling elements. The cage 85 is made of, for example, PEEK resin or brass. Further, a plurality of retaining portions 85a are formed at predetermined intervals in the circumferential direction of the cage 85, and are formed in an arc-shaped cross section capable of retaining the rolling elements 71. The retaining portions 85a are configured similarly to the retaining portions 82a of the second embodiment, and the rolling elements 71 inserted into the retaining portions 85a are restricted from axially escaping by the retaining portions 85a. To insert the rolling elements 71 into the retaining portions 85a, they are inserted from the radial direction of the retainer 85, similarly to the second embodiment.

[0055] In this embodiment, the groove depth h of the bearing groove 71a is set to a dimension that prevents the rolling elements 71 from riding up onto the groove shoulder 71b. That is, in this embodiment, in order to prevent the input of an excessive load to the bearing 70 due to deformation of the second disk 2, the radial gap rs is made larger than usual, and the contact angle becomes large. This is because there is a concern that the rolling elements 71 may ride up onto the groove shoulder 71b. In this embodiment, the groove depth h is set to d / 2, where d is the diameter of the rolling element 71. Moreover, the groove depth h is not limited to d / 2, but may be any dimension that prevents the rolling elements 71 from riding up onto the groove shoulder portions 71b.

[0056] Therefore, according to this embodiment, the groove depth h of the bearing groove 71a is dimensioned so that the rolling body 71 does not ride up onto the groove shoulder 71b, thereby preventing the rolling body 71 from riding up onto the groove shoulder 71b and maintaining the soundness of the bearing 70.

[0057] Of course, in this embodiment, the same effects as in the second embodiment can be obtained. In this embodiment, the bearing 70 is configured to include a plurality of rolling elements 71 and a cage 85 that rotatably holds the plurality of rolling elements 71, but instead, the bearing 70 may be configured with an angular contact ball bearing or a deep groove ball bearing. Even in this case, the groove depth of the bearing groove is set to a dimension that prevents the rolling elements from riding up onto the groove shoulder.

[0058] Fifth embodiment Fig. 11 shows a fifth embodiment, and is an enlarged cross-sectional view of a main part of a toroidal type continuously variable transmission. The fifth embodiment shown in Fig. 10 differs from the fourth embodiment shown in Fig. 10 in that the cage is outer-ring guided, and therefore this configuration will be described below, and the same components as those in the tenth embodiment will be given the same reference numerals and their description may be omitted. Note that the configuration other than the main parts shown in Fig. 11 is the same as that of the first embodiment, and therefore will not be shown.

[0059] In this embodiment, the bearing 70 includes a plurality of spherical rolling elements 71 and a cage 86 that holds the plurality of rolling elements 71 so that they can roll. The cage 86 is formed in a circular ring shape, and includes a holding portion 86a into which the spherical rolling elements 71 can be inserted from the radial direction and which can hold the inserted rolling elements. The cage 86 is made of, for example, PEEK resin or brass. Further, a plurality of retaining portions 86a are formed at predetermined intervals in the circumferential direction of the cage 86, and are formed in an arc-shaped cross section capable of retaining the rolling elements 71. The retaining portions 86a are configured similarly to the retaining portions 82a of the second embodiment, and the rolling elements 71 inserted into the retaining portions 86a are restricted from axially escaping by the retaining portions 86a. To insert the rolling elements 71 into the retaining portions 86a, they are inserted from the radial direction of the retainer 86, similarly to the second embodiment.

[0060] In this embodiment, the cage 86 is outer-ring guided. Therefore, the outer diameter of the cage 86 is larger than that of the cage 85 of the fourth embodiment, and the outer diameter surface of the cage 86 is close to the inner diameter surface 2m of the second disk 2 with a small gap. In addition, an oil groove 86g is formed in the outer diameter surface of the cage 86 along the circumferential direction, thereby ensuring the lubrication of the cage 86.

[0061] Therefore, according to this embodiment, the retainer 86 is outer ring guided and an oil groove 86g is formed on the outer diameter surface of the retainer 86, so that the lubrication of the retainer 86 can be ensured, and thus the soundness of the bearing 70 can be maintained. Of course, this embodiment can provide the same effects as the second and fourth embodiments. In addition, in this embodiment, the cage 86 is outer ring guided, but instead, it may be inner ring guided or rolling element guided. Furthermore, the cage 72 as shown in the first embodiment may be an outer ring guide, an inner ring guide, or a rolling element guide.

[0062] Furthermore, in the first to fifth embodiments, the present invention has been described with reference to a toroidal type continuously variable transmission for aircraft, but the present invention can also be applied to other uses (for example, automobile transmissions). In addition, in the first to fifth embodiments, the present invention has been described taking as an example the case where it is applied to a double-cavity half-toroidal continuously variable transmission, but is not limited to this, and the present invention can also be applied to a double-cavity full-toroidal continuously variable transmission, and further, to a single-cavity half-toroidal continuously variable transmission and a single-cavity full-toroidal continuously variable transmission.

[0063] Furthermore, in the first to fifth embodiments, the case where the output side disc 3 is pressed by the pressing device 12 has been described as an example, but in a toroidal type continuously variable transmission, the input / output relationship between the input side disc and the output side disc may be reversed. Therefore, the present invention can also be applied to a case where the input side disc 2 is pressed by the pressing device 12. In other words, as shown in Figs. 12 and 13, the present invention can also be applied to a toroidal type continuously variable transmission that includes an input shaft 1, an input side disc 2 that is splined to the input shaft 1 by a ball spline and rotates integrally with the input shaft 1, and an output side disc 3 that faces the input side disc 2 and is provided rotatably relative to the input shaft 1. [Explanation of symbols]

[0064] 1A Output shaft (shaft) 1m outer diameter surface 2 Input disk (second disk) 2A shaft hole 2m inner diameter surface 3 Output disk (first disk) 11 Power Roller 12 Pressing device 40 Input gear 41 Gear section 42 Sleeve 45a Outer diameter spline part 45b Inner diameter spline part 70 Bearings 71 Rolling elements 71a Bearing groove 72,82,83,84,85,86 Cage 82a,83a,84a,85a,86a Holding part 82b Claw part 83b Lubricating oil introduction part 83c slope 87 Lubricating oil supply hole 86g oil groove S1 Gap S2 deformation amount rs Radial clearance h Groove depth d diameter of rolling element

Claims

1. A toroidal type continuously variable transmission comprising: a shaft; a first disk and a second disk rotatably mounted on the shaft, the first disk and the second disk being concentric with each other and rotatable integrally with the shaft with their inner surfaces facing each other; a power roller sandwiched between the first disk and the second disk; and a bearing mounted between the shaft and the second disk, a retainer that holds the plurality of rolling elements in a rotatable manner, the retainer being configured to rotate about the shaft;

2. 2. The toroidal type continuously variable transmission according to claim 1, wherein a radial gap between the inner diameter surface of the second disk and the rolling elements is larger than a radial deformation of the inner diameter surface of the second disk.

3. 3. The toroidal type continuously variable transmission according to claim 1, wherein a bearing groove in which the rolling elements roll is provided on an outer diameter surface of the shaft or an inner diameter surface of the second disk.

4. 4. The toroidal type continuously variable transmission according to claim 3, wherein the cage includes a holding portion into which the rolling elements can be inserted from a radial direction and which can hold the inserted rolling elements.

5. 4. The toroidal type continuously variable transmission according to claim 3, wherein the cage is provided with a lubricant oil introduction portion that introduces lubricant oil into the bearing groove.

Images