JP2002276758A - Toroidal type continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toroidal type continuously variable transmission capable of improving accuracy of variable speed control by surely reducing friction in axial displacement of trunnions. SOLUTION: In this toroidal type continuously variable transmission, a plurality of trunnions 17 are provided between input and output discs coaxially arranged opposite to each other to be capable of axial displacement and inclination displacement around an axis. The trunnion 17 is provided with a power roller 15 coming into contact with the input and output discs. Inclination shafts 17b, 17c of the trunnions 17 each is provided with a inclination bearing 65. Yokes 50, 51 supported swingably are provided between trunnions 17. Both end portions of the trunnion 17 are supported by the yokes 50, 51 through the inclination bearings 65. An outer ring 66 of the inclination bearing 65 of each trunnion 17 is rotationally attached to the yoke 50, 51 through a support pin 70 to enable the yoke 50, 51 to swing with axial displacement of each trunnion 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toroidal type continuously variable transmission used as a transmission mechanism of, for example, an automobile.

[0002]

2. Description of the Related Art Toroidal-type continuously variable transmissions have been developed and put into practical use as transmission mechanisms for automobiles and the like.

FIG. 3 shows an example of a double-cavity half-toroidal type continuously variable transmission. The toroidal-type continuously variable transmission 10 includes a first cavity 11 and a second cavity 14.
14 is an input disk 12 and an output disk 1, respectively.
3 is provided.

A pair of power rollers 15 is provided between the input / output disks 12 and 13.
5 is in contact with the traction surface of each of the disks 12 and 13.

[0005] These power rollers 15
7 is mounted via a deflection shaft 19 and is rotatably supported by a power roller bearing 16. The trunnion 17 extends in a direction perpendicular to the axis of the input / output disks 12 and 13, and has a tilt displacement that rotates around a pivot 18 attached to a lower portion thereof and an axial displacement that moves in the axial direction. Supported as possible. The traction surface of each of the discs 12 and 13 has a concave shape obtained by rotating an arc around the pivot 18 about an axis perpendicular to the pivot 18.

Each input disk 12 is attached to the input shaft 20 so as to be movable in the axial direction thereof while being prevented from rotating by the ball splines 21 and 22, respectively.

Therefore, each input disk 12 is connected to the input shaft 2
0 and rotate together. The input shaft 20 is provided with a bearing 26 on a drive shaft 25 rotated by a drive source such as an engine.
Are rotatably connected via a.

Each output disk 13 is composed of both input disks 1
The input disk 12 and the output disk 13 of the first cavity 11 are opposed to each other, and the input disk 12 and the output disk 13 of the second cavity 14 are opposed to each other.

Each output disk 13 is rotatably supported on an input shaft 20 via bearings 30 and 31.
The output disks 13 are connected by a connecting member 32 and rotate in synchronization with each other. The connection member 32 is provided with an output gear 33.

A pressing mechanism 40 is provided on the back side of the input disk 12 in the first cavity 11, and the pressing mechanism 40 includes a cam disk 41 and a roller 42. The cam disk 41 is rotatably supported on the input shaft 20 via a thrust bearing 43.
Opposite surfaces of the cam disk 41 and the input disk 12 are cam surfaces 44 and 45, respectively. A plurality of rollers 42 are sandwiched between the cam surfaces 44 and 45.

When the drive shaft 25 rotates while the rollers 42 are sandwiched between the cam surfaces 44 and 45, the cam disk 41 rotates integrally with the drive shaft 25, and the first cavity is formed via the rollers 42. The input disk 12 at 11 is pressed toward the output disk 13 side, and the input disk 12 rotates integrally with the cam disk 41.

Further, since the reaction force received by the cam disk 41 is applied to the input shaft 20 via the thrust bearing 43, the input disk 12 in the second cavity 14 is pressed toward the output disk 13.

In this way, the cam disk 41 is
The input discs 12 are rotated by the torque of the engine transmitted to the output disk 13, the torque of each input disc 12 is transmitted to the output disc 13 via the power roller 15, and the output gear 33 rotates.

Each trunnion 17 is, as shown in FIG.
It comprises a main part 17a and tilting shafts 17b, 17c integrally formed on the upper and lower parts of the main part 17a. Tilt axis 17b,
17c protrudes from one side of the main portion 17a and is disposed coaxially with the pivot 18.

The power roller 15 is provided between the upper tilting shaft 17b of the trunnion 17 and the lower tilting shaft 17c.
a is rotatably supported by a deflection shaft 19 attached to the a.

Tilting shafts 17 at both ends of each trunnion 17
The b and 17c are supported via an upper yoke 50 and a lower yoke 51 provided on a casing 10a of the transmission 10. Tilt shafts 17b, 17 of trunnions 17
Each of c is provided with a tilt shaft bearing 53. The tilt shaft bearing 53 includes an outer ring 54 and a needle roller 55 as a rolling element interposed between the inner circumference of the outer ring 54 and the inner circumference of the tilt shafts 17b and 17c. These tilt shaft bearings 53 are fitted into circular fitting holes 56 formed at both ends of the yokes 50, 51, and these tilt shaft bearings 53 are provided.
Each of the trunnions 17 is rotatably supported by the yokes 50 and 51 via the.

A circular fitting hole 57 is formed at an intermediate portion between the yokes 50 and 51, and the fitting hole 57 is fitted on the outer periphery of a support shaft 58 attached to the casing 10a of the transmission 10.

Pulleys 59 are provided below the tilt shafts 17c of the trunnions 17, and a synchronous cable 6 is provided between the pulleys 59 to tilt the trunnions 17 in synchronization with each other.
0 is crossed over the cross.

Hydraulic cylinder mechanisms 61 are provided on the pivots 18 of the respective trunnions 17, and these hydraulic cylinder mechanisms 61 are driven through one control valve (not shown).

When the gear ratio is switched, each cylinder mechanism 61 is driven by the control valve, and each trunnion 17 is displaced in the axial direction. In accordance with this displacement, the peripheral surface of each power roller 15 and the input disk 12 and output disk 13 The direction of the tangential force acting on the contact portion with the traction surface changes. Then, the trunnion 17 tilts around the axis in accordance with the change in the direction of the force, and the tilting displacement causes the circumferential surface of the power roller 15 to abut on the traction surfaces of the input disk 12 and the output disk 13. And the rotation speed ratio between the input shaft 20 and the output gear 33 changes. The displacement of one trunnion 17 is sequentially fed back to the control valve, and based on this feedback, each trunnion 1
7 is controlled to an amount corresponding to the shift command, and the gear ratio is set to the target value.

When each of the trunnions 17 is displaced in the axial direction, the yokes 50 and 51 swing so as to be inclined with respect to the axis of the trunnions 17 in accordance with this operation. Yoke 50,
An outer peripheral surface of a support shaft 58 supporting an intermediate portion of the spherical member 51 has a spherical seat 58.
The spherical seat 58a enables the yokes 50 and 51 to swing with respect to the support shaft 58.

The outer peripheral surface of the outer ring 54 of the bearing 58 in each trunnion 17 is also a spherical seat 54a, and the spherical seat 54a allows the yokes 50,
51 can be swung.

When the trunnion 17 is displaced in the axial direction, the inner peripheral surface of the fitting hole 56 of the yokes 50 and 51 slides on the spherical seat 54a of the tilt shaft bearing 53 to generate friction. Here, if the friction between the inner peripheral surface of the fitting hole 56 and the spherical seat 54a of the tilt shaft bearing 53 is large, a large resistance is generated in the speed change operation, and the accuracy of the speed change control is reduced.

In Japanese Patent No. 3022212, a projection is formed on the yoke, and the projection keeps the contact position between the yoke and the trunnion constant irrespective of the axial movement of the trunnion. A technique has been proposed in which the amount of sliding between the two is reduced to reduce friction.

[0025]

SUMMARY OF THE INVENTION Patent No. 3022212
In the case of No. 1, it is possible to reduce the sliding amount between the spherical seat of the bearing and the yoke, but the sliding also causes friction, which lowers the shift control accuracy, and stabilizes the gear shifting. However, there is a problem that the stability, particularly during a sudden shift, is impaired.

Further, when a spherical seat is formed on the outer ring of the bearing, dedicated machining equipment for the machining and complicated machining steps are required, and furthermore, the surface of the spherical seat as the sliding surface and the fitting of the yoke are required. A heat treatment for obtaining abrasion resistance must be performed on the inner peripheral surface of the hole, and thus there is a problem that the cost is increased.

The present invention has been made in view of such a point. An object of the present invention is to reduce the friction when the trunnion is displaced in the axial direction, thereby improving the accuracy of the shift control. Another object of the present invention is to provide a toroidal-type continuously variable transmission that can be configured at a low cost.

[0028]

According to the present invention, a plurality of trunnions are provided between an input / output disk arranged coaxially opposite to each other to achieve axial displacement and axial rotation. Power rollers that are in contact with the input / output disks are rotatably provided on these trunnions, and tilt shafts at both ends of each trunnion are provided with tilt shaft bearings, respectively. In a toroidal-type continuously variable transmission in which both ends of each trunnion are supported by the yokes via the tilt shaft bearings, a yoke supported swingably is provided between the trunnions. The outer ring of the tilt shaft bearing is rotatably attached to the yoke via a pin so that the yoke can be swung with the axial displacement of each trunnion.

The invention according to claim 2 is characterized in that the pin supporting the outer ring of the tilt shaft bearing is provided with a friction reducing means for reducing friction with the yoke.

[0030]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. Parts corresponding to those of the conventional configuration are denoted by the same reference numerals, and description thereof is omitted.

In the present embodiment, each trunnion 17
The tilting shaft bearings 65 are respectively attached to the tilting shafts 17b and 17c at both ends. These tilt shaft bearings 6
5 is, for example, an outer ring 66, an inner periphery of the outer ring 66 and a tilt shaft 1
It comprises a plurality of needle rollers 67 as rolling elements rotatably interposed between the outer circumferences of the rotary shafts 7b and 17c, and are attached to the tilting shafts 17b and 17c without looseness in the axial direction. ing. The outer peripheral surface of the outer ring 66 is a flat cylindrical surface.

At both ends of the yokes 50 and 51, U-shaped notches 69 are formed as fitting portions.
The tilt shaft bearing 65 is inserted therein. And FIG.
As shown in the figure, the yokes 50 and 5 on both sides of the cutout 69 are provided.
The support pins 70 are coaxially inserted from the wall surface of the first to the inside of the notch 69, respectively, and the insertion tips of these support pins 70 are fitted and fixed to both sides of the outer ring 66 in the tilt shaft bearing 65, The tilt shaft bearing 65 is swingably supported by the yokes 50 and 51 via the support pins 70.

It is also possible to provide the support pins 70 integrally on both sides of the outer race 66 in advance. In this case, the yokes 50 and 51 are formed in a two-part structure, and the support pins 70 are provided. Enables the incorporation of

A bearing 71 such as a sliding bearing or a rolling bearing is fitted around the outer periphery of each support pin 70 as a friction reducing means.
0 and 51 are rotatably supported.

In such a configuration, the trunnion 17
Is displaced in the axial direction in response to the shift command, the tilt shaft bearing 65 is displaced in the axial direction integrally with the trunnion 17, and the yokes 50 and 51 move the support pins 70 in accordance with the displacement.
In the direction around the axis. That is, the yokes 50, 51
Swings so as to be inclined with respect to the horizontal.

The swinging motion of the yokes 50 and 51 is such that the support pin 70 of the tilt shaft bearing 65 of the trunnion 17 is
This is achieved by rotating relative to 0,51. The friction at the time of rotation of the support pin 70 is much smaller than the friction caused by the conventional sliding between the spherical seat of the outer ring of the bearing and the inner peripheral surface of the fitting hole of the yoke. The bearing 71 is provided as a reducing means, and therefore, the friction caused by the rotation of the support pin 70 can be further reduced.

As described above, the friction during the axial displacement operation of the trunnion 17 is reliably reduced, so that the axial displacement operation of the trunnion 17 is performed lightly and accurately, the precision of the shift control is increased, and Stability is improved, especially during sudden shifting.

At the time of rapid shifting, disturbances or the like may cause the displacements of the plurality of trunnions 17 in the axial direction to be inconsistent with each other, causing instability of synchronization. Since they are mechanically linked via the support pins 70 of the yokes 50 and 51 and the tilt shaft bearing 65, the extreme synchronization instability can be prevented.

Japanese Patent No. 2,568,684 discloses a technique in which a plurality of trunnions are linked via a yoke to suppress vibration. In this patent, as in the above-described conventional technique, a trunnion tilting shaft is provided. Since the outer peripheral surface of the outer ring of the provided bearing is spherical and the outer peripheral surface is in contact with the inner peripheral surface of the fitting hole formed in the yoke, the outer peripheral surface of the outer ring and the inner peripheral surface of the fitting hole are formed. Slip between the surface occurs,
It is difficult to completely match the movements of the axial displacements of the plurality of trunnions, which may cause synchronization instability.

In this embodiment, since the trunnions 17 corresponding to each other are mechanically linked via the yokes 50 and 51 and the support pins 76 as described above, the trunnions 17 can be accurately connected to each other. Can be synchronized.

In the present embodiment, since the support pin 70 is provided on the outer ring 66 of the tilt shaft bearing 65 to support the outer ring 66 so as to be swingable with respect to the yokes 50 and 51, the outer ring 66 is provided. It is not necessary to perform complicated processing such as making the outer peripheral surface of the outer ring a spherical surface, and heat treatment of the outer peripheral surface of the outer ring 66 and the inner peripheral surface of the notch 69 of the yokes 50 and 51 becomes unnecessary, thus reducing the cost. Can be.

Further, in the present embodiment, the yoke 5
A U-shaped notch 69 is formed at 0, 51, and this notch 69
Because the tilt shaft bearing 65 is arranged in the inside,
Compared to a case where a circular fitting hole is formed and a tilt shaft bearing is disposed therein as in the conventional structure, the ends of the yokes 50 and 51 from the center of the tilt shaft bearing 65 to the outside thereof are different. The protrusion L can be kept small, so that the mountability of this continuously variable transmission on an automobile or the like is improved.

In the above embodiment, the yoke 5
The intermediate portions 0 and 51 are swingably supported by the spherical seat 58a of the support shaft 58. However, as shown in JP-A-9-291997, the intermediate portion of the yoke is swingably supported by pins. It is also possible to adopt a structure that does this.

In the above-described embodiment, the support pin 70 is mounted so as to be inserted into the outer ring 66 of the tilt shaft bearing 65. However, the outer ring 66 and the support pin 70 may be integrally formed. Is thinner on the peripheral wall of the outer ring 66, which is advantageous in strength. However, in this case, the yoke 5
Since it becomes impossible to insert the support pin 70 into 0, 51,
The yokes 50 and 51 are configured in a split structure so that the support pins 70 are sandwiched between the yokes 50 and 51 to be supported.

Further, in the above-described embodiment, a so-called two-roller type transmission mechanism in which two power rollers are arranged between input / output disks facing each other has been described as an example.
The present invention can be applied to a continuously variable transmission of a three-roller type transmission mechanism in which three power rollers are arranged between input and output disks.

[0046]

As described above, according to the present invention,
The outer ring of the tilt shaft bearing of each trunnion is rotatably attached to the yoke via a pin to enable the yoke to swing due to the axial displacement of each trunnion, so that the friction at the time of axial displacement of the trunnion is reduced. It is possible to surely reduce the speed and improve the accuracy of the speed change control, and it is possible to eliminate the need for troublesome spherical machining and heat treatment for the tilt shaft bearing, thereby reliably reducing the cost.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a structure of a main part of a toroidal type continuously variable transmission according to an embodiment of the present invention.

FIG. 2 is a plan view showing a connection structure between a yoke and a tilt shaft bearing in the continuously variable transmission.

FIG. 3 is a sectional view showing the structure of a conventional toroidal-type continuously variable transmission.

FIG. 4 is a sectional view showing a structure of a main part of the conventional continuously variable transmission.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Continuously variable transmission 10a ... Casing 12 ... Input disk 13 ... Output disk 15 ... Power roller 17 ... Trunnion 17a ... Main part 17b, 17c ... Tilt axis 18 ... Axis 20 ... Input shaft 50, 51 ... Yoke 65 ... Tilt Rolling shaft bearing 66 ... Outer ring 67 ... Needle roller 69 ... Notch 70 ... Support pin 71 ... Bearing

Claims (2)

[Claims] A plurality of trunnions are provided between input / output disks coaxially opposed to each other so as to be capable of axial displacement and tilt displacement in a direction around an axis. A power roller is provided rotatably in contact with, a tilt shaft bearing is provided on each of the tilt shafts at both ends of each trunnion, and a yoke supported swingably is provided between the trunnions, In a toroidal type continuously variable transmission in which both ends of each trunnion are supported by the yoke via the tilt shaft bearing, the outer ring of the tilt shaft bearing of each trunnion is rotatably attached to the yoke via a pin. A toroidal-type continuously variable transmission characterized in that the yoke can be swung in accordance with the axial displacement of each trunnion. 2. The toroidal-type continuously variable transmission according to claim 1, wherein the pin supporting the outer ring of the tilt shaft bearing is provided with friction reducing means for reducing friction with the yoke.