JPH07229547A - Toroidal type continuously variable transmission - Google Patents

Abstract

PURPOSE:To miniaturize a device and reduce its weight so as to improve its durability and reliability by providing a slide part provided between the outer side face of a thrust bearing outer ring and the trunnion inside face and allowing displacement of the face direction on both side faces and solid lubricating agent film in one of a pair of faces forming the slide part. CONSTITUTION:An annular projection part 39 is formed on the inside face of a trunnion 6 and facing to the outer side face of the outer ring 30 of a thrust ball bearing 26, and the surface 39a is flat, and is brought in uniform contact with the outer side face 30a of the outer ring 30 so as to form a slide part, and at least one of the surface 39a and the outer side face 30a is covered with a film of a solid lubricant. Molybdenum disulfide, tungsten disulfide, etc., are used as the solid lubricant, and painting by a brush and physical gaseous phase composing method are suitable as a film formation method. Since the relative displacement between the outer ring 30 and the trunnion 6 is absorbed by the slide part, the relative displacement is made smooth. Any contact face damage caused by high pressure can be prevented. Consequently, miniaturization, of a transmission reducing its weight, its durability, and its reliability can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The toroidal type continuously variable transmission according to the present invention is used, for example, as a transmission for automobiles or as a transmission for various industrial machines.

[0002]

2. Description of the Related Art The use of a toroidal type continuously variable transmission as schematically shown in FIGS. 3 and 4 has been studied as a transmission for an automobile. This toroidal type continuously variable transmission supports the input side disk 2 concentrically with the input shaft 1 and is arranged concentrically with the input shaft 1, as disclosed in, for example, Japanese Utility Model Laid-Open No. 62-71465. The output disk 4 is fixed to the end of the output shaft 3. Inside the casing in which the toroidal type continuously variable transmission is housed, there are provided trunnions 6, 6 which swing around a pivot shaft 5, 5 which is in a twisted position with respect to the input shaft 1 and the output shaft 3.

Each trunnion 6, 6 has the pivots 5, 5 on the outer surface of both ends. The trunnions 6, 6 support the base ends of the displacement shafts 7, 7 at the central portions thereof, and the pivot shafts 5, 5,
By swinging each trunnion 6 around the center, the inclination angle of each displacement shaft 7, 7 can be adjusted freely. Power rollers 8, 8 are rotatably supported around displacement shafts 7, 7 supported by the trunnions 6, 6, respectively. The power rollers 8, 8 are sandwiched between the input side and output side disks 2, 4.

The inner surfaces 2a, 4a of the input-side and output-side disks 2, 4 which face each other have cross-sections which are concave surfaces obtained by rotating an arc about the pivot 5. The peripheral surfaces 8a, 8a of the power rollers 8, 8 formed in the spherical convex surface are in contact with the inner side surfaces 2a, 4a.

A loading cam type pressing device 9 is provided between the input shaft 1 and the input side disk 2, and the pressing device 9 causes the input side disk 2 to face the output side disk 4 and elastically moves. Pressing. This pressing device 9
Is a cam plate 10 that rotates together with the input shaft 1, and a retainer 11.
A plurality of (for example, four) rollers 12 held by
It is composed of 12 and. On one side surface (left side surface of FIGS. 3 to 4) of the cam plate 10, a cam surface 13 which is an uneven surface extending in the circumferential direction is formed, and the outer side surface of the input side disk 2 (right side of FIGS. 3 to 4). The same cam surface 14 is also formed on the surface). Then, the plurality of rollers 12, 12 are rotatably supported about a shaft in the radial direction with respect to the center of the input shaft 1.

When the toroidal type continuously variable transmission constructed as described above is used, when the cam plate 10 rotates as the input shaft 1 rotates, the cam surface 13 causes the plurality of rollers 12, 1 to rotate.
2 is pressed against the cam surface 14 on the outer surface of the input side disk 2. As a result, the input side disk 2 is pressed by the plurality of power rollers 8, 8 and at the same time, based on the meshing between the pair of cam surfaces 13, 14 and the plurality of rollers 12, 12. The input side disk 2 rotates. And
The rotation of the input side disk 2 is transmitted to the output side disk 4 through the plurality of power rollers 8 and the output shaft 3 fixed to the output side disk 4 rotates.

When the rotational speeds of the input shaft 1 and the output shaft 3 are changed and when deceleration is first performed between the input shaft 1 and the output shaft 3, the trunnions 6, 6 centering on the pivot shafts 5, 5 are used. 3, the displacement shafts 7, 7 are tilted as shown in FIG. 3, so that the peripheral surfaces 8a, 8a of the power rollers 8, 8 are connected to the inner side surface 2a of the input side disk 2 near the center and the output side. The inner surface 4a of the disk 4 is brought into contact with the outer peripheral portion of the disk 4, respectively.

On the contrary, when increasing the speed, the trunnions 6, 6 are swung as shown in FIG.
7 is inclined, and the peripheral surfaces 8a, 8a of the respective power rollers 8, 8
Are brought into contact with the outer peripheral portion of the inner side surface 2a of the input side disk 2 and the central portion of the inner side surface 4a of the output side disk 4, respectively. By setting the inclination angles of the displacement shafts 7, 7 in the middle between FIG. 3 and FIG. 4, an intermediate gear ratio can be obtained between the input shaft 1 and the output shaft 3.

Further, FIGS. 5 to 8 show the Japanese Patent Application No. 63-6929.
3 shows a more specific toroidal-type continuously variable transmission described in the microfilm of No. 3 (Actual Kaihei No. 1-173552). Input side disk 2 and output side disk 4
Is rotatably supported around a cylindrical input shaft 15 via needle bearings 16 and 16, respectively. The cam plate 10 is spline-engaged with the outer peripheral surface of the end portion (the left end portion in FIG. 5) of the input shaft 15 and is prevented from moving in the direction away from the input side disk 2 by the collar portion 17. Then, the cam plate 10 and the rollers 12 and 12 cause the input side disk 2 to rotate based on the rotation of the input shaft 15.
Is rotated while being pressed toward the output side disk 4,
A loading cam type pressing device 9 is configured. An output gear 18 is provided on the output side disk 4 with keys 19, 19
And the output side disk 4 and the output gear 18
It is designed so that and rotate in synchronization.

Both ends of the pair of trunnions 6, 6 are supported by the pair of support plates 20, 20 so as to be swingable and displaceable in the axial direction (front and back directions in FIG. 5, left and right directions in FIG. 6). There is.
The displacement shafts 7, 7 are supported in the circular holes 23, 23 formed in the intermediate portions of the trunnions 6, 6. The displacement shafts 7, 7 are parallel to each other and eccentric to the support shaft portion 2.
1 and 21 and pivots 22 and 22, respectively.
Of these, the support shaft portions 21 and 21 are attached to the circular holes 23 and 23, respectively.
Is rotatably supported on the inner side of the bearing via needle bearings 24, 24. In addition, the power rollers 8 and 8 are provided around the pivot shafts 22 and 22 and the needle rollers 25 and 25 are provided separately.
It is rotatably supported via.

The pair of displacement shafts 7, 7 are provided at positions opposite to the input shaft 15 by 180 degrees. or,
The direction in which the pivot shafts 22, 22 of the displacement shafts 7, 7 are eccentric to the support shafts 21, 21 is the input side,
The output side disks 2 and 4 rotate in the same direction (see FIG. 6).
And left and right directions). The eccentric direction is a direction substantially orthogonal to the direction in which the output shaft 15 is arranged.
Therefore, each of the power rollers 8 and 8 is supported so as to be slightly displaceable in the arrangement direction of the input shaft 15. As a result, even if the power rollers 8, 8 tend to be displaced in the axial direction of the input shaft 15 due to the dimensional accuracy of the components, etc., without applying an unreasonable force to the components,
This displacement can be absorbed.

Between the outer surface of each of the power rollers 8 and 8 and the inner surface of the intermediate portion of each of the trunnions 6, 6, there are thrust ball bearings 26, in order from the outer surface of the power rollers 8, 8. 26 and thrust needle bearings 27, 27 are provided. The thrust ball bearings 26, 26 support the loads in the thrust direction applied to the power rollers 8, 8 and allow the power rollers 8, 8 to rotate. Such thrust ball bearings 26, 26 have a plurality of balls 29, 29 and balls 29, 2 respectively.
An annular retainer 28, 28 for holding 9 in a rollable manner,
It is composed of an annular outer ring 30, 30. The inner ring raceways of the thrust ball bearings 26, 26 are formed on the outer side surfaces of the power rollers 8, 8 and the outer ring raceways are formed on the inner side surfaces of the outer races 30, 30 respectively.

Further, the thrust needle bearings 27, 27
Is composed of a race 31, a retainer 32, and needles 33, 33 as shown in FIGS. Race 3 of these
1 and the retainer 32 are combined so as to be slightly displaceable in the rotation direction. Also, these races 31 and cage 3
2 is an annular portion 34a whose center is the pivot shaft portion 22;
34b, and protrusions 35a and 35b that protrude diametrically outward from the partial outer peripheral edge of each annular portion 34a and 34b.

Such thrust needle bearings 27, 27
With the races 31 and 31 in contact with the inner side surfaces of the trunnions 6 and 6, the inner side surfaces and the outer ring 3 are
It is sandwiched between the outer surface of 0 and 30. The arrangement direction of each of the protrusions 35a and 35b is the same as that of the support shaft portion 21,
The eccentric directions of the pivot shaft portions 22, 22 with respect to 21 are matched. Such thrust needle bearings 27, 27 are
While supporting the thrust load applied to the outer rings 30, 30 from the power rollers 8, 8, the pivot shaft portion 22,
22 and the outer rings 30, 30 are the support shaft portions 21, 21.
Allows swinging around.

Further, drive rods 36, 36 are connected to one end portions (lower end portions in FIG. 6) of the trunnions 6, 6 respectively, and drive pistons 37, 37 are provided on outer peripheral surfaces of intermediate portions of the drive rods 36, 36. Is fixed. Then, the drive pistons 37, 37 are respectively connected to the drive cylinder 3
8 and 38 are oil-tightly fitted.

In the case of the toroidal type continuously variable transmission configured as described above, the rotation of the input shaft 15 is transmitted to the input side disk 2 via the pressing device 9. Then, the rotation of the input side disk 2 is transmitted to the output side disk 4 via the pair of power rollers 8, 8 and the rotation of the output side disk 4 is taken out from the output gear 18.

When changing the rotational speed ratio between the input shaft 15 and the output gear 18, the pair of drive pistons 37,
37 is displaced in opposite directions. As the drive pistons 37, 37 are displaced, the pair of trunnions 6,
6 are displaced in mutually opposite directions (for example, the power roller 8 on the right side in FIG. 6 is on the upper side in FIG. 6 and the power roller 8 on the left side in FIG. 6 is on the lower side in FIG. 6). As a result, the direction of the tangential force acting on the contact portion between the peripheral surfaces 8a, 8a of the power rollers 8, 8 and the inner side surfaces 2a, 4a of the input side disk 2 and the output side disk 4 changes. To do. Then, the trunnions 6, 6 swing in opposite directions with respect to the pivots 5, 5 pivotally supported by the support plates 20, 20 as the direction of the force changes.

As a result, as shown in FIGS.
The contact position between the peripheral surfaces 8a, 8a of the power rollers 8, 8 and the inner side surfaces 2a, 4a changes, and the input shaft 15
The rotational speed ratio between the output gear 18 and the output gear 18 changes.

In order to change the rotational speed ratio between the input shaft 15 and the output gear 18 in this manner, the displacement shafts 7, 7
When changing the inclination angle of each of the displacement axes 7, 7,
However, it slightly rotates about each of the support shaft portions 21, 21. As a result of this rotation, the thrust ball bearings 26, 2 are
6, the outer surface of the outer ring 30, 6, and each of the trunnions 6,
The inner surface of 6 is relatively displaced. Since the thrust needle bearings 27, 27 are present between the outer side surface and the inner side surface, the force required for this relative displacement is small. Therefore, as described above, a small force is required to change the inclination angles of the displacement shafts 7, 7.

[0020]

However, in the case of the toroidal type continuously variable transmission constructed and operated as described above, there are the following points to be solved.

The area where the trunnion 6 and the outer ring 30 face each other is limited, and the size (area) of the thrust needle bearings 27, 27 is also limited. Therefore, the number of the needles 33, 33 constituting the thrust needle bearings 27, 27 is limited, and all the needles 3
It is not possible to secure a sufficient contact area between the rolling surfaces of Nos. 3, 33 and the outer ring 30 and the race 31. Therefore, each of these needles 3
A large surface pressure acts on the contact portion between the rolling surfaces 3 and 33 and the outer ring 30 and the race 31, and the rolling fatigue life of this contact portion is shortened, and the durability of the toroidal continuously variable transmission is impaired.

Since the thrust needle bearings 27, 27 are provided, the number of parts increases. Moreover, since the thrust needle bearings 27, 27 are special ones that are not versatile, they cause an increase in the manufacturing cost of the toroidal type continuously variable transmission.

The toroidal type continuously variable transmission of the present invention was invented in view of the above circumstances.

[0024]

The toroidal type continuously variable transmission according to the present invention is an input side disk and an output side disk that are concentrically and rotatably supported in a state in which their inner side surfaces are opposed to each other. And a trunnion that swings about a pivot that is in a twisted position with respect to the center axes of these two disks, and a supporting shaft portion and a pivot shaft portion that are parallel and eccentric to each other. While being rotatably supported by the trunnion, the pivot shaft portion projecting from the inner surface of the trunnion and a displacement shaft that is rotatably supported around the pivot shaft portion, A power roller sandwiched between the power roller and a thrust ball shaft provided along the outer side surface of the power roller for supporting the load in the thrust direction applied to the power roller and permitting the rotation of the power roller. And a sliding portion that is provided between the outer surface of the outer ring that constitutes the thrust ball bearing and the inner surface of the trunnion, and that allows a displacement in the surface direction between the outer surface and the inner surface. At least one surface of the pair of surfaces constituting the moving part is coated with a solid lubricant film.

[0025]

The toroidal type continuously variable transmission of the present invention configured as described above has the same operation as the above-described conventional toroidal type continuously variable transmission, and is based on the same action as that of the conventional toroidal type continuously variable transmission. Is transmitted, and the rotation speed ratio between the rotation shaft and the rotation transmission member is further changed.

In particular, in the case of the toroidal type continuously variable transmission of the present invention, the size and cost can be reduced and the durability can be improved as compared with the case of the conventional toroidal type continuously variable transmission. That is, in the case of the toroidal type continuously variable transmission of the present invention, the relative displacement between the outer surface of the outer ring forming the thrust rolling bearing and the inner surface of the trunnion is absorbed by the sliding portion coated with the solid lubricant.
No thrust needle bearing like the conventional structure is provided. Therefore, the thrust load applied to the outer ring can be transmitted to the trunnion over a wide area, and the contact surface can be prevented from being damaged by high surface pressure. Further, since the thrust needle bearing is omitted, the structure is simplified, and the parts manufacturing, parts management, and assembling operations are all simplified, and the manufacturing cost can be reduced.

[0027]

FIG. 1 shows a first embodiment of the present invention.
The feature of the present invention resides in the structure of the portion that supports the outer ring 30 that constitutes the thrust ball bearing 26 with respect to the trunnion 6 so as to be displaceable, and the structure and operation of the other portions are as described above, for example. This is similar to the conventionally known toroidal type continuously variable transmission. Therefore, the description of the parts equivalent to those of the conventional structure will be omitted, and the characteristic parts of the present invention will be mainly described below.

An annular convex portion 39 is formed on the inner side surface of the trunnion 6 facing the outer side surface of the outer ring 30.
The surface 39a of the convex portion 39 is flat and evenly contacts the outer surface 30a of the outer ring 30 to form a sliding portion. Then, at least one of the surface 39a and the outer side surface 30a is covered with a film of solid lubricant. Suitable solid lubricants for forming such a film include molybdenum disulfide (MoS ₂ ), tungsten disulfide (WS ₂ ), polytetrafluoroethylene (PTFE), boron nitride (BN) and the like. Further, as a method for forming the film, coating with a brush, physical vapor phase synthesis method (PVD), chemical vapor phase synthesis method (CV)
D), baking, etc. are suitable.

In the case of the toroidal type continuously variable transmission of the present invention constructed as described above, the relative displacement between the outer ring 30 and the trunnion 6 forming the thrust ball bearing 26 is determined by the outer ring 30.
It is absorbed by the sliding portion formed by the abutting portion between the outer side surface 30a and the surface 39a of the convex portion 39. Since the coating film of the solid lubricant is present between the both surfaces 30a, 39a forming the sliding portion, the relative displacement between the both surfaces 30a, 39a is smoothly performed. Also, these both sides 30a,
Since 39a abut on each other uniformly over a wide area, the thrust load applied to the outer ring 30 can be transmitted to the trunnion 6 over a wide area, and the contact surface can be prevented from being damaged by high surface pressure. Further, since the thrust needle bearing is omitted, the structure is simplified, and the parts manufacturing, parts management, and assembling operations are all simplified, and the manufacturing cost can be reduced.

In the case of the illustrated embodiment, the projection 3
By forming 9, the cross-sectional modulus of the trunnion 6 is increased (the rigidity is improved), so that the surface pressure applied to the contact surface portion can be made more uniform. Furthermore, since the deformation amount of the trunnion 6 can be suppressed to a small amount, the trunnion 6 can be used as a center for reducing the size and weight.

Next, FIG. 2 shows a second embodiment of the present invention. In the case of this embodiment, the inner surface 6a of the trunnion 6 is
A circular convex portion 40 is formed on the surface of the circular convex portion 40, and a ring-shaped spacer 41 is mounted around the convex portion 40. Then, both side surfaces 42a and 42b of the spacer 41 are brought into contact with the inner side surface 6a of the trunnion 6 and the outer side surface 30a of the outer ring 30. Therefore, in the case of the present embodiment, the contact portion between the inner side surface 6a of the trunnion 6 and the one side surface 42a of the spacer 41, and the contact between the outer side surface 30a of the outer ring 30 and the other side surface 42b of the spacer 41. The contact parts are the sliding parts. In the case of the present embodiment, a solid lubricant film is formed on at least one of the four surfaces 6a, 42a, 42b, 30a forming these sliding parts.

In the case of this embodiment, unlike the case of the first embodiment described above, the rigidity of the trunnion 6 cannot be improved, but
Since there are two sliding parts, the relative displacement between the trunnion 6 and the outer ring 30 can be performed more smoothly.

[0033]

Since the toroidal type continuously variable transmission of the present invention is constructed and operates as described above, the toroidal type continuously variable transmission can be made smaller and lighter and the manufacturing cost can be reduced.
The durability and reliability can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is a sectional view showing the second embodiment.

FIG. 3 is a side view showing a basic configuration of a conventionally known toroidal type continuously variable transmission in a state of maximum deceleration.

FIG. 4 is a side view showing the same state at the time of maximum acceleration.

FIG. 5 is a sectional view showing an example of a conventional specific structure.

6 is a cross-sectional view taken along the line AA of FIG.

FIG. 7 is a view of the thrust needle bearing incorporated in the conventional structure as viewed from the same direction as FIG. 1.

FIG. 8 is an enlarged BB sectional view of FIG.

[Explanation of symbols]

 1 Input Shaft 2 Input Side Disk 2a Inner Side Surface 3 Output Shaft 4 Output Side Disk 4a Inner Side Surface 5 Axis 6 Trunnion 6a Inner Side Surface 7 Displacement Axis 8 Power Roller 8a Circumferential Surface 9 Pressing Device 10 Cam Plate 11 Cage 12 Roller 13, 14 Cam surface 15 Input shaft 16 Needle bearing 17 Collar part 18 Output gear 19 Key 20 Support plate 21 Support shaft part 22 Pivot shaft part 23 Circular holes 24, 25 Needle bearing 26 Thrust ball bearing 27 Thrust needle bearing 28 Cage 29 Ball 30 Outer ring 30a Outer side surface 31 Race 32 Retainer 33 Needle 34a, 34b Annular portion 35a, 35b Projection portion 36 Drive rod 37 Drive piston 38 Drive cylinder 39, 40 Convex portion 39a Surface 41 Spacer 42a, 42b Side surface

Claims (1)

[Claims] 1. In a state in which the inner surfaces of each other are opposed to each other,
An input-side disk and an output-side disk that are concentrically and rotatably supported, a trunnion that swings around a pivot that is in a twisted position with respect to the center axes of these disks, and a support that is parallel and eccentric to each other. A displacement shaft that has a shaft portion and a pivot shaft portion, and is rotatably supported by the trunnion by a support shaft portion of the shaft portion, and the pivot shaft portion is projected from the inner surface of the trunnion; A power roller sandwiched between the two disks while being rotatably supported around the shaft, and a thrust load applied to the outer surface of the power roller in the thrust direction. And a thrust ball bearing that allows the power roller to rotate, and a thrust ball bearing that is provided between the outer surface of the outer ring and the inner surface of the trunnion that form the thrust ball bearing. A toroidal provided with a sliding portion that allows displacement in the surface direction between the side surface and the inner side surface, and a solid lubricant film coated on at least one surface of a pair of surfaces forming the sliding portion. Type continuously variable transmission.