JPH1137241A - Shift controller of toroidal-type continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide compatibility of restriction of excessive rotation of a trunnion and miniaturization of a toroidal-type continuously variable transmission. SOLUTION: In a precession cam for transmitting the turning movement around the axis of a trunnion to a shift control valve through a feedback link, a normal controlling inclined surface 20 having the specified feedback gain to be used in normal, shift control is formed, a collisoin preventing inclined surface 21 having the large feedback gain is formed outside the normal controlling inclined surface 20 from the position in which the rotation angle of the trunnion exceeds the limit value in design or a value near the limit value to the position in which the trunnion is brought in contact with a stopper or the position just before the trunnion is brought in contact with the stopper, and a restoring inclined surface 22 having the small feedback gain is formed outside the collision preventing inclined surface 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a shift control device for a toroidal type continuously variable transmission used in a vehicle or the like.

[0002]

2. Description of the Related Art In a toroidal-type continuously variable transmission used in a vehicle such as an automobile, a shift control is performed by hydraulic pressure, and there is Japanese Patent Application Laid-Open No. 5-26317 proposed by the present applicant.

[0003] As shown in Fig. 4, the shape of the precess cam 2 for feeding the tilt angle of the power roller back to the speed change control valve to match the actual speed ratio to the target speed ratio is changed to the normal speed range. On both sides of the normal control slope 20 corresponding to the feedback gain, the collision preventing slopes 21 and 2 set to a larger feedback gain than in the normal control.
1 is provided to prevent the trunnion as a roller supporting member for supporting the power roller from colliding with the stopper when the tilting of the power roller becomes excessive. Here, since the feedback gain of the precess cam 2 'is represented by the inclination angle of the slope of the precess cam 2', the collision prevention slope 21 is formed as a slope having a larger angle than the normal control slope 20.

[0004]

However, in the above-mentioned prior art, since the collision prevention slope 21 having a large inclination angle is provided on both sides of the normal control slope 20 formed with a gentle inclination angle, the precess cam 2 'is not provided. The thickness H 'increases, and this thickness direction is the axial direction of the trunnion. Therefore, the axial length of the trunnion, that is, the overall height of the transmission increases, which hinders miniaturization of the continuously variable transmission. There was a problem of doing.

The present invention has been made in view of the above problems, and an object of the present invention is to achieve both suppression of excessive rotation of a trunnion and miniaturization of a toroidal-type continuously variable transmission.

[0006]

According to a first aspect of the present invention, a power roller sandwiched by an input / output disk and rotatably supported is rotatably supported, and is rotatable about a predetermined axis and axially displaceable. A roller support member, a shift control valve for controlling a hydraulic pressure to a hydraulic cylinder that drives the roller support member in the axial direction, a cam provided with a shaft portion that rotates around the axis of the roller support member, and a cam provided with the cam. The cam includes a feedback means for transmitting to the shift control valve via a responsive feedback link, and a stopper for restricting rotation of the roller support member beyond a predetermined value. A first cam surface having a predetermined feedback gain to be used, and a region where the rotation angle of the roller support member outside the first cam surface exceeds a design limit value or a value near the limit value. A toroidal-type continuously variable transmission having a second cam surface having a feedback gain increased compared to the first cam surface; Is formed from a position exceeding a design limit value or a value in the vicinity of the limit value to a position where the roller support member hits the stopper or a position immediately before hitting the stopper, and the outside of the second cam surface has a small feedback gain. 3 are formed.

[0007]

Therefore, when the roller support member attempts to rotate beyond the normal shift control range of the first cam surface, the roller link enters the second cam surface where the feedback gain is set to a large value. The speed of change of the hydraulic pressure from the hydraulic cylinder to the hydraulic cylinder is increased to prevent the trunnion roller support member from colliding with the stopper and quickly return to the normal speed control area of the first cam surface. When the roller support member rotates beyond the second cam surface, the third cam surface having a small feedback gain can return to the first cam surface which is a normal shift control range, and the feedback gain can be reduced. Is formed only in a predetermined section, and a third cam surface having a small feedback gain is formed outside the second cam surface. Since the, the overall height of the cam, the can be reduced compared to the total height of the conventional example, it is possible to shorten the axial dimension of the roller support member,
The total height of the toroidal-type continuously variable transmission can be reduced as compared with the conventional example, and it is possible to suppress excessive rotation of the roller supporting member and to reduce the size of the continuously variable transmission.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 schematically shows a transmission control device for a toroidal type continuously variable transmission. A lower end of one shaft portion 4A of a plurality of trunnions 4 (roller support members) has an axial displacement and a rotation around the shaft. The precess cam 2 for transmitting the displacement to the shift control valve 7 via the feedback link 54 is provided.

An engaging member 55 provided at one end of an L-shaped feedback link 54 is in sliding contact with a slope provided on an end face of the precess cam 2, and the feedback link 54 swings about a swing shaft 62. Also, feedback link 5
A ball 58 is disposed at the other end of the transmission 4 and engages with an engagement portion 90 provided at one end of the transmission link 9 to rotate the trunnion 4 (= tilt the power roller 3) and to displace in the axial direction. The power is transmitted to the spool 8 of the transmission control valve 7 connected in the middle of the transmission link 9.

At the other end of the transmission link 9, a pin 52a provided on a slider 52 driven in the axial direction by a step motor 50 as an actuator via a speed reduction mechanism 51 is provided.
Is formed, and the speed change link 9 is swung by the step motor 50 to a position corresponding to the target speed ratio.

When the step motor 50 drives the slider 52 according to a target speed ratio from a controller (not shown), the spool 8 moves according to the displacement of the speed change link 9,
The supply pressure port 17P of the shift control valve 7 is communicated with the port 17H or 17L, and pressure oil is supplied to the oil chamber 1H or 1L of the hydraulic servo cylinder 1 to drive the trunnion 4 in the axial direction. The power roller 3 tilts in response to the axial displacement of the trunnion 4 to change the gear ratio, and this tilting motion is transmitted to the speed change link 9 via the shaft portion 4A of the trunnion 4 and the feedback link 54, and When the speed ratio and the actual speed ratio match, the spool 8 becomes the port 17H,
The shift is terminated by returning to the neutral position for sealing the 17L and the supply pressure port 17P.

The rotation of the trunnion 4 beyond a predetermined rotation angle is restricted by a stopper (not shown).

As shown in FIGS. 2 and 3, the precess cam 2 has a normal control slope 20 (first first slope 20) having a gentle inclination angle corresponding to the feedback gain in the normal speed control area A.
The camming surface) is formed at the center, and the collision preventing slopes 21, 21 set to a feedback gain larger than that in the normal control are provided from both ends of the normal control slope 20.
The (second cam surface) is formed only in the predetermined collision prevention areas B, B.

The slope 21 for collision prevention rises at a steep inclination angle in order to prevent the trunnion 4 from colliding with a stopper (not shown) when the tilting of the power roller 3 becomes excessive, as in the prior art. Thus, the feedback gain in the collision prevention area is increased.

The anti-collision zones B, B are determined by the trunnion 4 from the limit value of the designed rotation angle or the vicinity of the limit value.
It is composed of a minute section corresponding to the rotation angle until the trunnion 4 collides with the stopper or the rotation angle just before the collision.

Outside the collision prevention areas B, B, return slopes 22, 22 having a gentle inclination angle are again provided.
(Third cam surface) is formed up to both ends of the cam surface, and the section of the return slope 22 is the return countermeasure areas C, C.

When the trunnion 4 hits the stopper after exceeding the collision prevention area B due to a variation in the relative position between the trunnion 4 and the stopper, etc.
When the feedback gain is set to be small as in the normal shift control area A, and when the feedback gain is set to be large in the area beyond the collision prevention area B like the anti-collision slope 21, the trunnion 4 is in the normal shift control area. Since there is no significant difference in the time required to return to the normal state, the inclination angle of the return slope 22, that is, the feedback gain, may be any value as long as the trunnion 4 can return to the normal shift control range A.

In FIG. 2, the central through-hole 2A
Is for fastening with the shaft portion 4A of the trunnion 4, and the cam surface 20R is a reverse cam surface that feeds back the displacement of the trunnion 4 to a reverse shift control valve (not shown).

The operation will be described next.

When the trunnion 4 attempts to rotate beyond the normal shift control range A, the trunnion 4 enters the collision prevention region B where the feedback gain is set to a large value. It increases in comparison with A. Accordingly, the speed of change of the hydraulic pressure to the hydraulic servo cylinder 1 can be increased to prevent the trunnion 4 from colliding with the stopper, and to quickly return to the normal speed control area A.

Here, the anti-collision areas B, B, in which the feedback gain is set to a large value, correspond to the rotation from the limit value of the designed rotation angle of the trunnion 4 or the vicinity of this limit value until the trunnion 4 collides with the stopper. The angle is set only in a minute section corresponding to the rotation angle immediately before the collision or just before the collision. Since the outside of the collision prevention areas B and B is again set as the return countermeasure areas C and C having a small feedback gain, there is a variation in manufacturing. When the trunnion 4 rotates beyond the collision prevention range B, it can be returned to the normal shift control range A with a small feedback gain.

At this time, in a region where the trunnion 4 collides with the stopper, the trunnion 4 is different between the case where a large feedback gain is held as in the conventional example and the case where the feedback gain is reduced as in the present embodiment. There is no significant difference in the time required to return to the normal shift control area A.

Accordingly, by reducing the feedback gain of the return countermeasure area C beyond the collision prevention area B to a value at which the trunnion 4 can return to the normal gear change control area A, FIG.
As shown in the figure, the overall height H of the precess cam 2 can be reduced as compared with the overall height H 'of the conventional example, and the trunnion 4 can be reduced.
Can be reduced in the axial direction, the total height of the toroidal-type continuously variable transmission can be reduced as compared with the conventional example, excessive rotation of the trunnion 4 can be suppressed, and the size of the continuously variable transmission can be reduced. It is possible to achieve both.

[Brief description of the drawings]

FIG. 1 shows one embodiment of the present invention, and is a conceptual diagram of a shift control device.

FIG. 2 is a perspective view of a precess cam.

FIG. 3 is a side elevational view showing the slope of the precess cam.

FIG. 4 is a side elevational view showing a slope of a conventional precess cam.

[Explanation of symbols]

 Reference Signs List 1 hydraulic servo cylinder 2 precess cam 3 power roller 4 trunnion 4A shaft 7 shift control valve 8 spool 9 shift link 20 slope for normal control 21 slope for preventing collision 22 slope for return 50 step motor 54 feedback link 58 ball 59 pin 62 swing axis

Claims (1)

[Claims] A roller support member rotatably supporting a tiltable power roller sandwiched by an input / output disk and rotatable about a predetermined axis and displaceable in an axial direction; and the roller support member. A shift control valve for controlling a hydraulic pressure to a hydraulic cylinder that drives the shaft in the axial direction; a cam provided on a shaft for rotating the roller support member around the axis; and a feedback link responsive to the cam. A feedback means for transmitting to the valve; and a stopper for restricting rotation of the roller supporting member beyond a predetermined value. The cam has a predetermined feedback gain used in normal shift control. In the region where the rotation angle of the first cam surface and the rotation angle of the roller supporting member outside the first cam surface exceeds a design limit value or a value near the limit value, the fan angle is smaller than the first cam surface. A toroidal-type continuously variable transmission having a second cam surface having an increased feedback gain, wherein the cam has a second cam surface whose rotation angle of a roller supporting member is at or near a design limit value or a limit value. From the position beyond the value of
A toroidal-type continuously variable transmission, wherein a roller supporting member is formed up to a position where the roller hits the stopper or a position immediately before hitting the stopper, and a third cam surface having a small feedback gain is formed outside the second cam surface. Transmission control device.