JPH05580B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a toroidal type continuously variable speed control system which is capable of continuously variable speed by disposing a power roller in pressure contact between input and output disks and changing the inclination of the power roller. This relates to transmissions.

Conventional technology and its problems Conventionally, as described in Japanese Patent Application Laid-Open No. 58-54262,
The support that rotatably supports the power roller is rotated in the direction of its own axis (direction perpendicular to the power roller axis).
A toroidal continuously variable transmission is known in which the direction of the tangential force acting on the power roller is changed by operating the power roller, and the inclination of the power roller is changed by the component of this tangential force. ing.

In this case, hydraulic working chambers are provided at both ends of the support, and a control valve is provided between the hydraulic working chamber and the hydraulic pressure supply source, and this control valve switches the oil path to the angular hydraulic working chamber. Therefore, the line pressure acting on the hydraulic working chamber is controlled ON and OFF to operate the support body in the axial direction.

By the way, as the input/output disk rotates, the support body is biased in the rotational direction of the input disk.
A large back pressure acts on the drive-side hydraulic chamber facing the rotational direction of the input disk, and this back pressure increases as the input torque of the input disk increases. Therefore, in order to quickly move the support to a desired shift position, the line pressure acting on the drive-side hydraulic chamber must be set to a value that exceeds the maximum input torque. However, if the line pressure is set high, the high line pressure will always act even when the input torque is low, resulting in a problem of increased oil pump discharge loss and, as a result, poor fuel efficiency.

Purpose of the Invention The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to use a toroidal type system that can regulate the line pressure to the necessary minimum level commensurate with the input torque and reduce the discharge loss of the oil pump as much as possible. The purpose of the present invention is to provide a step-change transmission.

Structure of the Invention In order to achieve the above-mentioned object, the present invention provides a regulator valve between a control valve and a hydraulic pressure supply source, and a drive-side hydraulic chamber facing the rotational direction of the input disk is connected to the regulator valve. It communicates with the back pressure chamber of the valve.

In other words, by applying the back pressure of the drive side hydraulic operation chamber to the back pressure chamber of the regulator valve, the line pressure can be automatically regulated in proportion to the input torque, and as a result, the input torque is reduced. When the pressure is low, the line pressure can also be kept low, and discharge loss can be reduced as much as possible.

DESCRIPTION OF EMBODIMENTS FIG. 1 shows an example of a toroidal continuously variable transmission according to the present invention, in which 1 is a toroidal transmission section, 2 is a control valve, 3 is a regulator valve, and 4 is a toroidal type continuously variable transmission.
and 5 are an oil tank and an oil pump that constitute a hydraulic pressure supply source.

Opposing input disk 1 of toroidal transmission section 1
1 and an output disk (not shown), two power rollers 12 are disposed in pressure contact, and each power roller 12 is rotatably supported by a support 14 via a shaft 13. Supported. At both ends of the support body 14, cylinders 16a,
Pistons 15a and 15b that can freely slide inside 16b are arranged in series, and the support 14 can move together with the pistons in the axial direction (in the vertical direction in the figure) and can also rotate around its own axis. It is. Hydraulic working chambers 17a and 17b are formed inside the cylinders 16a and 16b, and the side facing the rotation direction of the input disk 11 (indicated by the arrow in the figure) is the drive side. The hydraulic working chamber 17a is on the opposite side, and the non-drive side hydraulic working chamber 17b is on the opposite side.

The control valve 2 includes a sleeve 22 slidably inserted into a valve body 21 and a spool 23 slidably inserted into the sleeve 22. The sleeve 22 is actuated in the axial direction by an actuator 24 of a speed ratio control device, and the left end of the spool 23 is constantly in contact with the precise cam 25 and the biasing force of a spring 26. This presis cam 25 is connected to the upper end of one of the supports, for example, the left support 14,
It rotates together with the support body 14 to move the spool 23 forward and backward.

The regulator valve 3 has a spool 32 inserted into a valve body 31 so as to be freely advanced and retracted, and the spool 32 is urged rightward by a spring 34 provided in a back pressure chamber 33. A central port 35 of the regulator valve 3 is connected to the discharge side of the oil pump 5.
The adjacent port 36 is connected to the suction side of the oil pump 5. The central port 35 is connected to the central port 27 of the control valve 2 via an oil passage 61, and an oil passage 62 branched from the oil passage 61 is connected to the right end port 37 of the regulator valve 3. ing. The back pressure chamber 33 of the regulator valve 3 is connected to the drive-side hydraulic chamber 17a of the toroidal transmission section 1 via an oil passage 63, and further connected to the left side of the control valve 2 via an oil passage 64 branched from the oil passage 63. is connected to port 28 of. On the other hand, the non-drive side hydraulic chamber 17b is connected to the right port 29 of the control valve 2 via an oil passage 65.

In the toroidal continuously variable transmission with the above configuration,
When the engine is started, the oil pump 5 is driven, and the hydraulic pressure generated by the oil pump 5 is sent to the central port 35 of the regulator valve 3. This oil pressure acts on the right end of the spool 32 through the oil passage 62, and moves the spool 32 to the left against the spring 34. This allows port 3
5 and 36 communicate with each other, and the oil is drained to the suction side of the oil pump 5. Therefore, the central port 35
The oil pressure in the oil passage 61 connected to the line is maintained in a state where this oil pressure and the spring force of the spring 34 are balanced (line pressure).

Here, when changing the gear ratio of the toroidal transmission section 1, the sleeve 22 of the control valve 2 is actuated, for example, to the right in the figure by the actuator 24. As a result, the ports 27 and 28 are in communication L, and the line pressure acts on the drive-side hydraulic chamber 17a through the oil passages 61 and 64, and the port communicates with the non-drive-side hydraulic chamber 17b through the oil passage 65. 29 is drained through a hole 23a provided in the spool 23. Therefore, the hydraulic pressure in the drive-side hydraulic chamber 17a increases, and the left support 1
4 moves upward, and the right support 14 moves downward. Along with this, the direction of the force in the connection direction applied to the power roller 12 changes, so the left power roller 12 and support 14 rotate clockwise, and the right power roller 12 and support 14 rotate to the left. Rotate in the rotational direction. That is, the toroidal transmission section 1 shifts to the speed increasing side. The precise cam 25, which rotates together with the left support 14, rotates counterclockwise and pushes the spool 23 to the right until the port 28 is closed. As described above, the toroidal transmission section 1 is controlled to a desired transmission ratio,
And this gear ratio is maintained. Note that the above operation is similar to that described in the aforementioned Japanese Patent Laid-Open No. 58-54262.

In the middle of the above gear shifting operation, the input disk 11
As the input torque applied to the
is pushed downward, and the right support member 14 is pushed upward, so that it takes time to reach the desired gear ratio, or it becomes impossible to maintain this gear shift position. Therefore, it is usually necessary to maintain the line pressure at a high value that does not hinder operation even when the maximum input torque is applied, which causes a discharge loss of the oil pump.

In the present invention, the drive-side hydraulic chamber 17a is connected to the oil passage 6.
3 to the back pressure chamber 33 of the regulator valve 3, an increase in the hydraulic pressure in the drive-side hydraulic chamber 17a due to an increase in input torque is instantaneously connected to the back pressure chamber 33 of the regulator valve 3. It was reported to 33,
Push the spool 32 to the right, that is, in the direction to close the port 37. As a result, the line pressure within the oil passage 61 increases, and a high hydraulic pressure proportional to the input torque is applied to the drive-side hydraulic chamber 17a. In other words, the line pressure is regulated to always exceed the input torque by the action of the back pressure chamber 33 of the regulator valve 3, so it is necessary to maintain the line pressure at a value that always exceeds the maximum input torque. There is no.

FIG. 2 is a diagram showing the pressure regulating operation of the regulator valve 3, where the solid line A indicates the drive side hydraulic operation chamber 17.
It shows the change in back pressure due to the input torque acting on a, and the dashed line B shows the change in line pressure.
The oil pressure difference between the solid line A and the dashed-dotted line B is given by the spring force of the spring 34 of the regulator valve 3. In this way, even if the input torque changes, the line pressure is always regulated higher than the back pressure due to the input torque, so there is no problem in controlling the toroidal transmission section 1, and when the input torque is small, the line pressure Since the discharge loss of the oil pump can be kept low, the discharge loss of the oil pump can be reduced as much as possible.

In addition, the broken line C in Fig. 2 indicates the regulator valve 3.
This is a case where the area of the back pressure chamber 33 is made smaller than other parts, and the oil pressure difference with the solid line A is made smaller as the speed moves toward the high speed side. In this way, losses during high-speed running can be further reduced.

Effects of the Invention As is clear from the above explanation, according to the present invention, the back pressure of the drive side hydraulic working chamber is applied to the back pressure chamber of the regulator valve, so the line pressure is automatically adjusted in proportion to the input torque. Pressure can be regulated and discharge loss of the oil pump can be reduced as much as possible.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a toroidal continuously variable transmission according to the present invention, and FIG. 2 is a diagram showing a pressure regulating operation of a regulator valve. DESCRIPTION OF SYMBOLS 1... Toroidal transmission part, 11... Input disk, 12... Power roller, 14... Support body, 1
7a... Drive side hydraulic operation chamber, 2... Control valve, 3... Regulator valve, 33... Back pressure chamber, 34... Spring, 5... Oil pump, 63... Oil passage.

Claims (1)

[Claims] 1. An input/output disk, a power roller disposed in pressure contact between the input/output disks, a support that rotatably supports the power roller, is movable in the axial direction and rotatable around the axis, and In a toroidal continuously variable transmission, which is provided with a hydraulic working chamber connected to both ends to actuate the support body in the axial direction, and a control valve that controls hydraulic pressure to the hydraulic working chamber, the control valve and the hydraulic pressure are connected to each other. A toroidal continuously variable transmission characterized in that a regulator valve is provided between the supply source and a drive side hydraulic chamber facing the rotational direction of the input disk is communicated with a back pressure chamber of the regulator valve. Machine.