Toroidal type continuously variable transmission

Abstract

To provide a toroidal type continuously variable transmission capable of suppressing wear of an engagement part of a disc and a shaft due to deformation of the disc.SOLUTION: A toroidal type continuously variable transmission comprises: an input shaft 1; an input side disc 2 provided so as to be rotatable integrally with the input shaft 1 and an output side disc 3 provided so as to be rotatable relative to the input shaft 1, which are concentrically arranged with each other on the input shaft 1 so that their inside surfaces are opposite to each other; and a power roller 11 sandwiched between the two discs, where an extension part 40 extending in an axial direction of the input shaft 1 is provided on a small end surface 2e of the input side disc 2, and the extension part 40 engages with the input shaft 1.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a toroidal continuously variable transmission that can be used in automotive, aircraft generators, or transmissions of various industrial machines.

Background Art

[0002] For example, a double-cavity toroidal continuously variable transmission used as an automotive transmission is configured as shown in FIGS. 4 and 5. As shown in FIG. 4, an input shaft 1 is rotatably supported inside a casing 50. Two input-side disks 2, 2 and two output-side disks 3, 3 are attached to the outer periphery of the input shaft 1. Further, an output gear (transmission gear) 4 is rotatably supported on the outer periphery of an intermediate portion of the input shaft 1. Output-side disks 3, 3 are connected to cylindrical flange portions (sleeves) 4a, 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 the input-side disk 2 located on the left side in FIG. 4 and a cam plate (loading cam) 7. Further, the output gear 4 is supported inside the casing 50 via a partition wall 13 formed by coupling two members. Thus, while the output gear 4 can rotate about the axis O of the input shaft 1, displacement in the direction of the axis O is prevented.

[0003] The output-side disks 3, 3 are rotatably supported about the axis O of the input shaft 1 by needle bearings 5, 5 interposed between the output-side disks 3, 3 and the input shaft 1. The input-side disk 2 on the left side in FIG. 4 is supported on the input shaft 1 via a ball spline 6, and the input-side disk 2 on the right side in FIG. 4 is spline-coupled to the input shaft 1. These input-side disks 2 rotate together with the input shaft 1. Further, a power roller 11 (see FIG. 5) is rotatably clamped between the inner surfaces (concave surfaces; also referred to as traction surfaces) 2a, 2a of the input-side disks 2, 2 and the inner surfaces (concave surfaces; also referred to as traction surfaces) 3a, 3a of the output disks 3, 3.

[0004] On the inner peripheral surface 2c of the input-side disk 2 located on the right side in FIG. 4, a stepped portion 2b is provided, and the stepped portion 1b provided on the outer peripheral surface 1a of the input shaft 1 abuts against this stepped portion 2b. Also, the back surface (the right surface in FIG. 4) of the input-side disk 2 abuts against a loading nut 9 screwed onto a screw portion formed on the outer peripheral surface of the input shaft 1. Thereby, displacement of the input-side disk 2 in the direction of the axis O with respect to the input shaft 1 is substantially blocked. Further, a disc spring 8 is provided between the cam plate 7 and the flange portion 1d of the input shaft 1, and this disc spring 8 applies a pressing force (preload) to the contact portions 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. 5 is a cross-sectional view taken along line A-A of FIG. 4. As shown in FIG. 5, inside the casing 50, a pair of trunnions 15, 15 that swing about a pair of pivot shafts 14, 14 that are in a twisted position with respect to the input shaft 1 are provided. In FIG. 5, the illustration of the input shaft 1 is omitted. Each of the trunnions 15, 15 has a pair of bent wall portions 20, 20 formed in a state of bending toward the inner surface side at both ends in the longitudinal direction (the vertical direction in FIG. 5) of the support plate portion 16. And, by this bent wall portion 20, 20, a concave pocket portion P for accommodating the power roller 11 is formed in each of the trunnions 15, 15. Also, on the outer surface of each bent wall portion 20, 20, the pivot shafts 14, 14 are provided concentrically with each other.

[0006] A circular hole 21 is formed in the central portion of the support plate portion 16, and the base end portion 23a of the displacement shaft 23 is supported in this circular hole 21. By swinging each trunnion 15, 15 about each pivot 14, 14, the inclination angle of the displacement shaft 23 supported at the central portion of each of these trunnions 15, 15 can be adjusted. Further, around the tip end portion 23b of the displacement shaft 23 protruding from the inner surface of each trunnion 15, 15, each power roller 11 is rotatably supported, and each of the power rollers 11, 11 is sandwiched between each input side disk 2, 2 and each output side disk 3, 3. Note that the base end portion 23a and the tip end portion 23b of each displacement shaft 23, 23 are eccentric with respect to each other.

[0007] In addition, each pivot 14, 14 of each trunnion 15, 15 is supported so as to be swingable and displaceable in the axial direction (vertical direction in FIG. 5) with respect to a pair of yokes 23A, 23B, and the trunnions 15, 15 are restricted in their horizontal movement by each of the yokes 23A, 23B. Each of the yokes 23A, 23B is formed in a rectangular shape by press working or forging of a metal such as steel. Four circular support holes 18 are provided at the four corners of each of the yokes 23A, 23B, and the pivots 14 provided at both ends of the trunnion 15 are swingably supported in these support holes 18 via radial needle bearings 30. Further, a circular locking hole 19 is provided at the central portion in the width direction (left - right direction in FIG. 5) of the yokes 23A, 23B, and the inner peripheral surface of this locking hole 19 is a cylindrical surface into which spherical posts 64, 68 are fitted. That is, the upper yoke 23A is swingably supported by a spherical post 64 supported by the casing 50 via a fixing member 52, and the lower yoke 23B is swingably supported by a spherical post 68 and the upper cylinder body 56 of a drive cylinder 31 that supports this spherical post 68.

[0008] Note that each displacement axis 23, 23 provided on each trunnion 15, 15 is provided at a position 180 degrees opposite to each other with respect to the input shaft 1. Further, the direction in which the tip portions 23b of these displacement axes 23, 23 are eccentric with respect to the base end portions 23a is the same direction (vertically reversed in FIG. 5) with respect to the rotation directions of both disks 2, 2, 3, 3. Further, the eccentric direction is a direction substantially orthogonal 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 when 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 caused by the thrust load generated by the pressing device 12, no excessive force is applied to each component member, and this displacement is absorbed.

[0009] 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 (thrust bearing) 24, which is a thrust rolling bearing, and a thrust needle bearing 25 are provided in order from the side of the outer surface of the power roller 11. Among these, the thrust ball bearing 24 supports the thrust direction load applied to each power roller 11 while allowing the rotation of each of these power rollers 11. Each such thrust ball bearing 24 is composed of a plurality of balls (hereinafter referred to as rolling elements) 26, 26, an annular cage 27 that rotatably holds each of these rolling elements 26, 26, and an annular outer ring 28. Further, the inner ring raceway of each thrust ball bearing 24 is formed on the outer surface (large end face) of each power roller 11, and the outer ring raceway is formed on the inner surface of each outer ring 28.

[0010] Further, 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 from the power roller 11 to each outer ring 28 while allowing the power roller 11 and the outer ring 28 to swing about the base end portion 23a of each displacement axis 23.

[0011] Furthermore, drive rods (trunion shafts) 29, 29 are provided at one end (the lower end in FIG. 5) of each trunion 15, 15, and drive pistons (hydraulic pistons) 33, 33 are fixedly provided on the outer peripheral surfaces of the middle portions of the drive rods 29, 29. These drive pistons 33, 33 are each tightly fitted into a drive cylinder 31 constituted by an upper cylinder body 56 and a lower cylinder body 57 in an oil-tight manner. The drive pistons 33, 33 and the drive cylinder 31 constitute a drive device 32 for displacing each trunion 15, 15 in the axial direction of the pivot shafts 14, 14 of these trunions 15, 15.

[0012] In the case of the toroidal continuously variable transmission configured as described above, the rotation of the input shaft 1 is transmitted to the input-side disks 2, 2 via the pressing device 12. Then, the rotation of these input-side disks 2, 2 is transmitted to the output-side disks 3, 3 via the pair of power rollers 11, 11, and further, the rotation of these output-side disks 3, 3 is 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 to each other. Along with the displacement of these drive pistons 33, 33, the pair of trunions 15, 15 are displaced in opposite directions to each other. For example, the left power roller 11 in FIG. 5 is displaced downward in the figure, and the right power roller 11 in the figure is displaced upward in the figure. As a result, the direction of the tangential force acting on the contact portions between the peripheral surfaces 11a, 11a of these 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. Along with this change in the direction of the force, the trunions 15, 15 swing (tilt) in opposite directions around the pivot shafts 14, 14 pivotally supported by the yokes 23A, 23B.

[0014] As a result, the contact positions between the peripheral surfaces 11a, 11a of the power rollers 11, 11 and the inner surfaces 2a, 3a change, 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 elastic deformation amounts of the respective constituent members change, the power rollers 11, 11 and the outer rings 28, 28 attached to these power rollers 11, 11 slightly rotate about the base end portions 23a, 23a of the displacement shafts 23, 23. Since thrust needle bearings 25, 25 are respectively present between the outer surfaces of these outer rings 28, 28 and the inner surfaces of the support plate portions 16 constituting the trunnions 15, 15, the rotation is performed smoothly. Therefore, as described above, the force for changing the inclination angles of the displacement shafts 23, 23 can be small.

Prior Art Documents

Patent Documents

[0015]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0016] By the way, as shown in FIG. 6, the reaction cam side (the side where the loading cam type pressing device is not provided) of the toroidal continuously variable transmission is mainly composed of a disk (input side disk) 2 on which the load from the power roller 11 acts and a shaft (input shaft) 1 that supports the disk 2. Due to the load from the power roller 11, the disk 2 deforms by the number of power rollers 11 per rotation. Since the disk 2 deforms with a large deformation amount and a high vibration frequency, there is a concern that slip occurs at the engaging portion between the disk 2 and the shaft 1, particularly at the contact surfaces 2s, 1s where the disk 2 and the shaft 1 are in contact with each other in the axial direction, and wear (fretting wear) occurs. Even in the conventional toroidal continuously variable transmission described in Patent Document 1 and Patent Document 2, the contact surface between the disk and the shaft is on the inner side in the radial direction of the disk, and is easily affected by the deformation of the disk, and there is a concern that wear (fretting wear) may occur.

[0017] The present invention has been made in view of the above circumstances, and an object thereof is to provide a toroidal continuously variable transmission capable of suppressing wear of an engagement portion between a disk and a shaft due to deformation of the disk.

Means for Solving the Problems

[0018] In order to achieve the above object, the toroidal continuously variable transmission of the present invention includes a shaft, a first disk provided concentrically with the shaft and rotatable integrally with the shaft with their inner surfaces facing each other, and a second disk rotatably provided with respect to the shaft, and a power roller sandwiched between these two disks. In the toroidal continuously variable transmission, An extension portion extending in the axial direction of the shaft is provided on the small end surface of the first disk, It is characterized in that the extension portion is engaged with the shaft.

[0019] When the first disk is deformed by the load acting from the power roller during the operation of the toroidal continuously variable transmission, the portion farther from the inner surface (traction surface) of the first disk in the axial direction is less affected by the deformation. That is, the portion on the small end surface side of the first disk is less affected by the deformation. Therefore, in the present invention, an extension portion extending in the axial direction of the shaft is provided on the small end surface of the first disk, and this extension portion is engaged with the shaft. Therefore, the engaged portion is separated from the small end surface of the first disk, and thus is separated from the traction surface of the first disk in the axial direction, so that wear of the engagement portion between the disk and the shaft due to deformation of the disk can be suppressed.

[0020] Further, in the above configuration of the present invention, the extension portion is engaged with the shaft by screwing, The direction of the helix of the screw of the screw engagement may be directed toward the tightening side by the torque acting when the shaft rotates in one direction during the operation of the toroidal continuously variable transmission.

[0021] For example, during the operation of a toroidal continuously variable transmission for an aircraft generator, basically the shaft rotates in one direction and a torque in a certain direction acts on the shaft. Therefore, when the extending portion is engaged with the shaft by screwing as in the above configuration, since the direction of the helix of the screw of the screw engagement is directed toward the tightening side by the torque acting when the shaft rotates in one direction during the operation of the toroidal continuously variable transmission, loosening of the screw does not occur during the operation torque action.

[0022] Further, in the above configuration of the present invention, the tightening torque of the screw may be larger than the torque when a torque acts in the direction opposite to the screw tightening when the shaft rotates in one direction during the operation of the toroidal continuously variable transmission.

[0023] According to such a configuration, since the tightening torque of the screw is larger than the torque when a torque acts in the direction opposite to the screw tightening, the screw does not loosen even if an unintended torque acts during operation.

Effect of the Invention

[0024] According to the present invention, wear of the engagement portion between the disk and the shaft due to deformation of the disk can be suppressed.

Brief Description of the Drawings

[0025]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0026] Hereinafter, embodiments of the present invention will be described with reference to the drawings. (First Embodiment) FIG. 1 is a semi-planar cross-sectional view showing a toroidal continuously variable transmission according to the first embodiment, and FIG. 2 is a semi-planar cross-sectional view of the main part. The toroidal continuously variable transmission of this embodiment is a so-called double cavity type half toroidal continuously variable transmission, and two input side disks (first disks) 2, 2 and two output side disks (second disks) 3, 3 are attached to the outer periphery of the input shaft (shaft) 1 to be configured. Also, cylindrical output gears 4, 4 are provided coaxially and integrally with the output side disks 3, 3 on the back surfaces of the output side disks 3, 3. The output side disks 3, 3 are rotatably supported about the axis O of the input shaft 1 by needle bearings 5, 5 interposed between them and the input shaft 1.

[0027] Also, one (right side in FIG. 1) input side disk 2 is supported via a ball spline 6 at one end of the input shaft 1 so as to rotate with the input shaft 1. Therefore, one input side disk 2 can move in the axial direction of the input shaft 1 (left side in FIG. 1). The other (left side in FIG. 1) input side disk 2 is externally fitted to the other end of the input shaft 1 and is configured to rotate with the input shaft 1. Also, the other input side disk 2 is restricted from moving outward in the axial direction of the input shaft 1 (left side in FIG. 1) by engagement of an extension portion 40, which will be described later, with the input shaft 1. Also, power rollers 11 are rotatably clamped between the inner surfaces (concave surfaces) 2a, 2a of the input side disks 2, 2 and the inner surfaces (concave surfaces) 3a, 3a of the output side disks 3, 3.

[0028] Further, the input shaft 1 is rotationally driven by a drive shaft (not shown) via a loading cam type pressing device 12 provided on the back side (right side in FIG. 1) of the input side disk 2 located on the right side in FIG. 1. The pressing device 12 includes a cam plate 20 that rotates together with a drive shaft (not shown) and a plurality of cam rollers 22. A cam surface, which is an unevenness (wave portion) extending in the circumferential direction, is formed on one side surface (left side surface in FIG. 1) of the cam plate 20, and a cam surface having a similar shape is also formed on the outer side surface (right side surface in FIG. 1) of the input side disk 2.

[0029] In such a pressing device 12, when the rotational torque of the input side disk 2 and the cam plate 20 increases, the input side disk 2 is pressed away from the cam plate 20 by the cam action. When a rotational force is input to the input shaft 1, the input side disks 2, 2 rotate integrally with the input shaft 1, and the rotation is transmitted to the output side disks 3, 3 by the power rollers 11, 11 at a constant speed ratio. Further, the rotation of the output side disks 3, 3 is transmitted to an output shaft (not shown) via a transmission gear (not shown) etc. from the output gear 4.

[0030] A thrust bearing 31 is provided on one end side (right end side in FIG. 1) of the input shaft 1. This thrust bearing 31 has an inner ring 31a formed on the outer peripheral portion of the input shaft 1, an outer ring 31b formed on the inner peripheral portion of the cam plate 20, and rolling elements 31c interposed between the inner ring 31a and the outer ring 31b. Also, a disc spring 28 for applying a preload to the input side disk 2 is provided between the cam plate 20 and the input side disk 2, and the input side disk 2 is pressed against the power roller 11 by the biasing force of this disc spring 28.

[0031] Also, in the present embodiment, as shown in FIGS. 1 and 2, an extension portion 40 extending in the axial direction of the input shaft 1 is integrally provided on the small end surface 2e of the input side disk (first disk) 2 on the anti-cam side (the side where the loading cam type pressing device 12 is not provided).

[0032] The extending portion 40 is formed in a cylindrical shape, and the extending portion 40 is engaged with the input shaft 1. That is, first, a notch groove 1e is formed to extend in the circumferential direction at the end portion (the left end portion in FIGS. 1 and 2) of the input shaft 1. This notch groove 1e has a contact surface 1f orthogonal to the axis O of the input shaft 1. The contact surface 1f is formed in an annular surface shape centered on the axis O. Further, the extending portion 40 has an extending portion main body 40a formed in a cylindrical shape centered on the axis O (axis), and a disk-shaped inner flange portion 40b coaxially and integrally formed with the extending portion main body 40a at the tip end portion (the right end portion in FIGS. 1 and 2) of the extending portion main body 40a. This inner flange portion 40b is formed so as to project annularly inward at the end portion of the extending portion main body 40a. Then, the extending portion main body 40a is externally fitted to the outer peripheral surface of the input shaft 1, the inner flange portion 40b is inserted into the notch groove 1e, and is in contact with the contact surface 1f. Thereby, the extending portion 40 is engaged with the input shaft 1.

[0033] In a toroidal continuously variable transmission, as shown in FIG. 6, during operation, due to the load from the power roller 11, the input-side disk 2 deforms at a high frequency, so there is a concern that slip may occur at the engagement portion between the input-side disk 2 and the input shaft 1, particularly at the contact surfaces 1s and 2s, resulting in wear (fretting wear). In a conventional toroidal continuously variable transmission, the contact surfaces 1s and 2s between the input-side disk 2 and the input shaft 1 are on the radially inner side of the input-side disk 2, and are easily affected by the deformation of the input-side disk 2, and there is a concern that wear (fretting wear) may occur.

[0034] On the other hand, in the toroidal continuously variable transmission of the present embodiment, as shown in FIG. 2, an extending portion 40 extending in the axial direction of the input shaft 1 is provided on the small end surface 2e of the input-side disk 2, and this extending portion 40 is engaged with the input shaft 1 such that the inner flange portion 40b of the extending portion 40 is in contact with the contact surface 1f of the input shaft 1. Therefore, this contacting part (the part where the contact surface 1f and the inner flange part 40b are in contact) is separated from the small end surface 2e of the input-side disk 2, and thus is axially separated from the traction surface 2a of the input-side disk 2. As a result, it is less likely to be affected by the deformation of the input-side disk 2. Therefore, wear of the engaging part between the input-side disk 2 and the input shaft 1 (especially the part where the inner flange part 40b contacts the contact surface 1f) due to the deformation of the input-side disk 2 can be suppressed.

[0035] (Second Embodiment) FIG. 3 is a half-plane cross-sectional view of a main part showing a toroidal continuously variable transmission according to the second embodiment. The toroidal continuously variable transmission of this embodiment is a double-cavity type half-toroidal continuously variable transmission for an aircraft (generator), and it shifts the rotation with a variable rotational speed from an aircraft engine so as to have a constant rotational speed and outputs it to the generator. Further, in this embodiment, the output gear 4 in the first embodiment serves as an input gear (not shown), and for example, the rotational force from the rotational shaft of the turbine of the engine is transmitted to the input gear via gears and the like. In this embodiment, since the pressing device has the same configuration as the pressing device 12 in the first embodiment, its illustration and description are omitted.

[0036] Also, in this embodiment, with respect to the toroidal continuously variable transmission of the first embodiment, the arrangement relationship between the input-side disk and the output-side disk is reversed, and what was the input shaft 1 in the first embodiment has become the output shaft 1A. That is, as shown in FIG. 3, the output-side disk (first disk) 3 is externally fitted to the end of the output shaft 1A and rotates together with the output shaft 1A. Further, the output-side disk 3 is restricted from moving axially outward (leftward in FIG. 3) of the output shaft 1A by engaging with an extending portion 41 described later on the output shaft 1A.

[0037] On the small end face 3e of the output-side disk (first disk) 3 located on the reaction cam side (the side where the loading cam type pressing device is not provided), an extension portion 41 extending in the axial direction of the output shaft 1A is integrally provided with the output-side disk 3. The extension portion 41 is formed in a cylindrical shape, and an internal thread 41a is formed on its inner peripheral surface. Further, the end portion of the output shaft 1A does not reach the small end face 3e of the output-side disk 3 in the axial direction, and the end portion of the output shaft 1A is a cylindrical small-diameter portion 1g. This small-diameter portion 1g is formed by notching the end portion (the left end portion in FIG. 3) of the output shaft 1A into a rectangular cross-section, and an annular contact surface 1h is formed at the base end portion (the right end portion in FIG. 3) of the small-diameter portion 1g. Further, an external thread 41b that engages with the internal thread 41a is formed on the outer peripheral surface of the small-diameter portion 1g. And the extension portion 41 is engaged with the output shaft 1A by screwing of the internal thread 41a and the external thread 41b. Further, in this engaged state, the tip end face (the right end face in FIG. 3) of the extension portion 41 is in contact with the contact surface 1h of the output shaft 1A.

[0038] Also, in the present embodiment, the direction of the helix of the screw in the screwing of the internal thread 41a and the external thread 41b is directed toward the side that is tightened by the torque acting when the output shaft 1A rotates in one direction during the operation of the toroidal continuously variable transmission. That is, during the operation of the toroidal continuously variable transmission for an aircraft generator as in the present embodiment, basically, a torque in a certain direction acts on the output shaft 1A. Therefore, as described above, when the extension portion 41 is engaged with the output shaft 1A by screwing, the direction of the helix of the screw is directed toward the side that is tightened by the torque acting when the output shaft 1A rotates in one direction during the operation of the toroidal continuously variable transmission.

[0039] Furthermore, in the present embodiment, the tightening torque during the screw engagement between the internal thread 41a and the external thread 41b is larger than the torque when a torque acts in the direction opposite to the screw tightening when the output shaft 1A rotates in one direction during the operation of the toroidal continuously variable transmission. For example, when the rotation of the engine is output to the generator via the toroidal continuously variable transmission of the present embodiment, if an emergency stop signal is input, the generator is decelerated, and as a result, a torque acts on the output shaft 1A in a direction opposite to the screw tightening during operation. In this case, the screw tightening torque is set larger than the torque when the torque acts in the direction opposite to the screw tightening. Therefore, even if an unintended torque acts during operation, the screw does not loosen.

[0040] According to the present embodiment, an extension portion 41 extending in the axial direction of the output shaft 1A is provided on the small end face 3e of the output side disk 3, and this extension portion 41 is engaged with the output shaft 1A by screwing of a female screw 41a and a male screw 41b. Therefore, the engaged portion is axially separated from the traction surface 3a of the output side disk 3 by being separated from the small end face 3e of the output side disk 3, so it is less likely to be affected by the deformation of the output side disk 3. Therefore, wear of the engagement portion between the output side disk 3 and the output shaft 1A due to the deformation of the output side disk 3 can be suppressed. Also, the portion where the tip surface of the extension portion 41 and the contact surface 1h of the output shaft 1A are in contact is axially separated from the traction surface 3a of the output side disk 3, so it is less likely to be affected by the deformation of the output side disk 3. Therefore, wear of the contact portion between the output side disk 3 and the output shaft 1A due to the deformation of the output side disk 3 can be suppressed.

[0041] Further, the extension portion 41 is engaged with the output shaft 1A by screwing, and the direction of the helix of the screw of the screwing is directed toward the tightening side by the torque acting when the output shaft 1A rotates in one direction during the operation of the toroidal continuously variable transmission. Therefore, loosening of the screw (female screw 41a and male screw 41b) does not occur during the action of the torque during operation. Furthermore, the tightening torque of the screw (female screw 41a and male screw 41b) is larger than the torque when the torque acts in the direction opposite to the screw tightening when the output shaft 1A rotates in one direction during the operation of the toroidal continuously variable transmission. Therefore, even if an unintended torque acts during operation, the screw does not loosen.

[0042] In the first embodiment, an extension portion 40 extending in the axial direction of the input shaft 1 is provided on the small end face 2e of the input-side disk 2, and the case where the extension portion 40 is engaged with the input shaft 1 has been described as an example. However, in the present invention, the arrangement relationship between the input-side disk 2 and the output-side disk 3 is reversed, and as in the second embodiment, an extension portion 40 extending in the axial direction of the output shaft 1A is provided on the small end face 3e of the output-side disk 3, and the extension portion 40 may be engaged with the output shaft 1A. In the second embodiment, the case where the extension portion 41 is provided on the small end face 3e of the output-side disk 3 and the extension portion 41 is engaged with the output shaft 1A by screwing has been described as an example. However, in the present invention, the arrangement relationship between the input-side disk 2 and the output-side disk 3 is reversed, and as in the first embodiment, an extension portion 41 is provided on the small end face 2e of the input-side disk 2, and the extension portion 41 may be engaged with the input shaft 1 by screwing.

[0043] In the first and second embodiments, the present invention has been described by taking the case of applying it to a double-cavity half-toroidal continuously variable transmission as an example. However, the present invention is not limited to this, and the present invention can also be applied to a double-cavity full-toroidal continuously variable transmission. Furthermore, the present invention can also be applied to a single-cavity half-toroidal continuously variable transmission and a single-cavity full-toroidal continuously variable transmission.

Explanation of Reference Numerals

[0044] 1 Input shaft (shaft) 1A Output shaft (shaft) 2 Input-side disk 2e Small end face 3 Output-side disk 3e Small end face 11 Power roller 40, 41 Extension portion 41a Female thread 41b Male thread

Claims

1. In a toroidal continuously variable transmission comprising a shaft, a first disk provided concentrically and rotatable integrally with the shaft with their inner surfaces facing each other, a second disk rotatable relative to the shaft, and a power roller sandwiched between the two disks, an extension portion extending in the axial direction of the shaft is provided on the small end surface of the first disk, the toroidal continuously variable transmission, characterized in that the extension portion is engaged with the shaft.

2. the extension portion is engaged with the shaft by screwing, the toroidal continuously variable transmission according to claim 1, characterized in that the direction of the helix of the screw is directed toward the tightening side by the torque acting when the shaft rotates in one direction during the operation of the toroidal continuously variable transmission.

3. the toroidal continuously variable transmission according to claim 2, characterized in that the tightening torque of the screw is greater than the torque when torque acts in the direction opposite to screw tightening when the shaft rotates in one direction during the operation of the toroidal continuously variable transmission.

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