JPH10213213A - Hydraulic control device of toroidal type continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To discharge an air in servo piston both rooms quickly and ensure a fovarable change gear ratio control, in the case of entering to a change gear ratio control as an oil being in a high viscosity after leaving alone for a long term, by introducing a line pressure to the servo piston both rooms in a parking state. SOLUTION: When a spool valve element 27 for inputting a speed change control valve 25 is in a state driven to a right side through the pinion 7 of a step motor in response to a change gear ratio order, a power roller 1 is off set to a lower side through a servo piston 5 and a tranion 4. After leaving a vehicle provided with such toroidal continuously variable transmission alone for a long term, when an engine is started, the line pressure introduced to a valve device 36 is introduced in the oil rooms 21, 22 of the servo piston 5 through oil passages 37, 38 from line pressure supply ports 36a, 36d. Thereby, the air gathered in the oil rooms 21, 22 is discharged quickly and a favorable speed change response is displayed by the hydraulic supply control by the speed change control valve 25.

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 hydraulic control device of a toroidal type continuously variable transmission used for a vehicle or the like.

[0002]

2. Description of the Related Art As a toroidal type continuously variable transmission employed in a vehicle such as an automobile, for example, the one shown in FIGS. 5 and 6 is known (see Japanese Patent Application Laid-Open No. 5-39850).

In FIG. 1, reference numeral 1 denotes a power roller, which presses the power roller 1 between input / output disks 2 and 3 arranged in a direction perpendicular to the axis. The input and output disks 2 and 3 have opposing surfaces formed as toroidal surfaces, and the outer surface of the power roller 1 is formed as a spherical surface in contact with these toroidal surfaces. The rotational power to the input disk 2 is transmitted to the output disk 3 via the rotation of the power roller 1, and the power roller 1 is tilted around an axis O ₂ orthogonal to the rotation axis O ₁ to rotate the input and output disks 2, 2. By changing the contact position with respect to 3, the input / output rotation ratio (speed ratio) can be changed steplessly.

[0004] In this continuously variable transmission, the power roller 1 is supported via the eccentric shaft 14, power roller 1 is the same level of the rotation axis O ₁ and the rotation axis O ₃ of input and output disks 2, 3 When the power roller 1 is displaced in the direction of the tilt axis O ₂ to offset the rotation axis O ₁ from the rotation axis O ₃ of the input / output disks 2 and ₃ , The power roller 1 naturally tilts in a direction corresponding to the offset direction to change the tilt angle.

Namely, rotatably supports the power roller 1 to the trunnion 4 via an eccentric shaft 14, while the rotatable trunnions 4 about the tilting axis O _2, can be displaced to its tilt axis direction I do. This displacement is generated by the servo piston 5, and the servo piston 5 is stroke-controlled by the shift control valve 6. Therefore, the transmission control valve 6 is supplied with line pressure to the input port 6a, and connects the output ports 6b and 6c to the chambers on both sides of the servo piston 5, respectively. The speed change control valve 6 is provided with a speed ratio command from a pinion 7 driven by a step motor. In response to this command, the input sleeve valve element 8 strokes and the relative position with respect to the feedback spool valve element 9 is It is changed from the joint position. Accordingly, the shift control valve 6 supplies the line pressure of the input port 6a from the one output port 6b to the corresponding one chamber of the servo piston 5 in response to the new speed ratio command, and the other side of the servo piston 5 opens the corresponding chamber. Drain from the other output port 6c to offset the power roller 1 with respect to the input / output disks 2 and 3 in the corresponding direction. With this offset, the power roller 1 naturally changes the tilt angle in the direction corresponding to the speed ratio command.

The displacement (offset) and the tilt of the power roller 1 in the tilt axis direction are controlled by the precess cam 1 coupled thereto.
0, the cam surface 1
The rotation of the link 11 about the pivot 12 is fed back to the feedback spool valve 9 of the transmission control valve 6 through the rotation of the link 11 around the pivot 12.
The link 11 is an L-shaped lever, and abuts the feedback spool valve 9 via an adjusting screw 13 screwed to the end of the lever. The feedback spool valve element 9 follows the displacement of the input sleeve valve element 8 according to the speed ratio command by the above-mentioned feedback, and returns to the original relative position accordingly. Therefore, when the power roller 1 reaches the tilt angle corresponding to the gear ratio, the offset is set to 0 by the shift control valve 6 via the servo piston 5 and is maintained at the tilt angle (speed ratio).

[0007]

However, in this conventional hydraulic control device for a toroidal-type continuously variable transmission, the shift control valve 6 is not operated until the vehicle starts running and the control of the gear ratio is started. Therefore, good gear ratio control may not be obtained when the vehicle starts running immediately after the engine is started at a low temperature, for example, after the vehicle has been left for a long period of time.

That is, if the vehicle is left unused for a while, air gradually accumulates in the chamber of the servo piston 5. In such a state, the vehicle starts running immediately after starting the engine at a low temperature. When the gear ratio control is started, although the hydraulic pressure is sent from the transmission control valve 6 into the chamber of the servo piston 5, since the viscosity of the oil is high, a flow rate sufficient to discharge the air in the chamber of the servo piston 5 is sufficient. Not supplied. For this reason, the discharge of the air in the room of the servo piston 5 is delayed, and during that time, the speed ratio control becomes unstable.

An object of the present invention is to solve such a problem.

[0010]

According to a first aspect of the present invention, there is provided a power roller sandwiched between an input / output disk and rotatably and tiltably supported, and a servo piston capable of moving the power roller in a tilt axis direction. And a shift control valve that controls the supply of pressure to both servo piston chambers in response to a speed ratio command, and offsets the power roller from a position where the rotation axis intersects the input / output disk axis during gear shifting. In this way, the power roller is tilted so that the gear ratio is directed to the command value, and the tilt and movement of the power roller are fed back to the shift control valve, so that the tilt angle of the power roller is adjusted to the gear ratio. In the toroidal-type continuously variable transmission configured to keep the power roller at the position of offset 0 when the angle corresponding to the command value is reached, the vehicle is in a parking state. The so as to introduce the line pressure to the servo piston both chambers to come.

According to a second aspect of the present invention, there is provided a power roller sandwiched between an input / output disk and supported rotatably and tiltably,
It has a servo piston that can move the power roller in the tilting axis direction and a shift control valve that controls the supply of pressure to both servo piston chambers in response to a gear ratio command. By moving the axis so as to be offset from the position where the axis intersects with the input / output disk axis, the power roller is tilted so that the gear ratio is directed to the command value, and the tilt and movement of the power roller are fed back to the shift control valve. Accordingly, when the toroidal continuously variable transmission is configured to keep the power roller at the offset 0 position when the tilt angle of the power roller becomes the angle corresponding to the command value of the gear ratio, the vehicle is in a parking state. Is provided with valve means for introducing line pressure to both chambers of the servo piston.

In a third aspect based on the second aspect, the valve means introduces line pressure into both servo piston chambers when a manual valve interlocking with a select lever for selecting a travel range is at a parking position. If it is at any other position, the introduction of the line pressure is shut off.

In a fourth aspect based on the third aspect, the valve means is mechanically linked to the manual valve.

According to a fifth aspect of the present invention, there is provided a power roller sandwiched between an input / output disk and rotatably and tiltably supported,
It has a servo piston that can move the power roller in the tilting axis direction and a shift control valve that controls the supply of pressure to both servo piston chambers in response to a gear ratio command. By moving the axis so as to be offset from the position where the axis intersects with the input / output disk axis, the power roller is tilted so that the gear ratio is directed to the command value, and the tilt and movement of the power roller are fed back to the shift control valve. Accordingly, in the toroidal-type continuously variable transmission configured to maintain the power roller at the position of the offset 0 when the tilt angle of the power roller becomes an angle corresponding to the command value of the gear ratio, the shift control valve is The line pressure port always connects to the high-side servo piston chamber that offsets the power roller in the direction to shift the gear ratio to the high side. And it has a power roller structure communicating with at least one port communicating with the low-side servo piston chamber which is offset to the low side in the direction to shift.

In a sixth aspect based on the fifth aspect, the speed change control valve has a line pressure port located on both sides of the spool responsive to the speed ratio command, a port communicating with the high side servo piston chamber, and a low side. It has a groove that can communicate simultaneously with a port that communicates with the servo piston chamber.

In a seventh aspect based on the fifth aspect, the speed change control valve has a spool responsive to tilting and movement of the power roller inside a sleeve responsive to a speed ratio command. The line pressure port has a groove that can simultaneously communicate with a port communicating with the high-side servo piston chamber via a sleeve and a port communicating with the low-side servo piston chamber.

[0017]

According to the first aspect of the present invention, when in the parking state, the line pressure is introduced into both chambers of the servo piston,
For this reason, even if the vehicle starts running immediately after starting the engine at a low temperature and enters the gear ratio control while the oil viscosity is high, even if the air is trapped in both servo piston chambers after long-term storage, The air in both chambers of the servo piston is quickly discharged before the control is started. Therefore, the start can be performed immediately after the start at the low temperature while securing the good speed ratio control by the hydraulic pressure supply control by the speed change control valve.

According to the second aspect of the present invention, the line pressure is introduced into both chambers of the servo piston by the valve means when the vehicle is in the parking state. Therefore, good gear ratio control is ensured by the hydraulic pressure supply control by the gear change control valve. In addition, the vehicle can be started immediately after starting at a low temperature.

According to the third aspect, when the manual valve is at the parking position, the line pressure is introduced into both chambers of the servo piston, and when the manual valve is at any other position, the introduction of the line pressure is interrupted. And good gear ratio control can be secured.

According to the fourth aspect, since the valve means is mechanically linked to the manual valve, the hydraulic circuit can be simplified.

According to the fifth aspect, the line pressure is always introduced from the shift control valve into at least one of the high-side servo piston chamber and the low-side servo piston chamber. Is quickly discharged, while air bubbles generated during traveling or the like can be rapidly discharged.

According to the sixth aspect, the line pressure can always be introduced into at least one of the high-side servo piston chamber and the low-side servo piston chamber by the groove provided on the spool that responds to the speed ratio command.

According to the seventh aspect, the line pressure can be always introduced into at least one of the high-side servo piston chamber and the low-side servo piston chamber by the groove provided on the spool in response to the tilt and movement of the power roller.

[0024]

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, 1 is a power roller sandwiched between the input and output disks 2 and 3, 4 is a trunnion that rotatably supports the power roller 1 via an eccentric shaft 14,
Reference numeral 5 denotes a servo piston of the hydraulic cylinder 20, which allows the trunnion 4 to be rotatable around the tilt axis of the power roller 1 and is displaceable (offset) in the tilt axis direction.
Are the oil chambers 2 on both sides of the servo piston 5 of the hydraulic cylinder 20
This is a shift control valve that controls the supply of hydraulic pressure to the hydraulic pumps 1 and 22.
The structures of the power roller 1, the input / output disks 2, 3, the trunnion 4, the hydraulic cylinder 20, the servo piston 5, and the like are the same as those shown in FIGS.

The speed change control valve 25 has an input spool valve body 27 responsive to a speed ratio command in a valve hole 26 and a feedback sleeve valve body responsive to the offset and tilt of the power roller 1 on the outer periphery of the spool valve body 27. 28 are mounted.

A line pressure is guided to an input port (line pressure port) 25a of the shift control valve 25 from a hydraulic supply source (not shown) via a line pressure oil passage.
The oil chambers 21 and 22 on both sides of the servo piston 5 of the hydraulic cylinder 20 correspond to ports 25b and 25c provided at predetermined positions on both sides (left and right in the drawing) of the hydraulic passage 3 respectively.
0, 31 are connected.

The feedback sleeve valve body 28 includes:
Openings 28 corresponding to each port 25a, 25b, 25c
a, 28b and 28c are provided. Further, the adjusting screw 13 of the link 11 responsive to the precess cam 10 connected to the lower end of the rod of the servo piston 5 abuts on the rear end of the sleeve valve body 28, and the offset and tilt of the power roller 1 are fed back. You.

The input spool valve body 27 has lands 27b, 27c corresponding to the openings 28b, 28c of the feedback sleeve valve body 28, and the lands 27b, 27.
A groove 27a is provided between the openings c and c so that the openings 28b and 28c can communicate with the opening 28a at the same time. In this case, if the width of the groove 27a is A and the length between the open ends of the openings 28b and 28c is B, then A> B. A pinion 7 of a step motor is meshed with a rack portion of the rear shaft of the spool valve body 27, and is stroked in the valve shaft direction according to a speed ratio command from a controller (not shown).

Reference numeral 35 denotes a manual valve interlocked with a select lever for selecting a travel range. When the engine is in the forward range, the line pressure is applied to the forward / reverse switching mechanism (not shown) of the continuously variable transmission from the forward range port 35e. When it is in the reverse range, the line pressure is supplied from the reverse range port 35b to the reverse side of the forward / reverse mechanism of the continuously variable transmission. Also, except when in the parking range (forward range, reverse range, neutral)
The line pressure is supplied from a predetermined valve port 35c to a control port 36e of a valve device (valve means) 36 described later. However, the upper side in the figure shows the position of the parking range that closes the line pressure port 35d, the lower solid line shows the position of the reverse range, and the dotted line shows the neutral position.

The valve device 36 is connected to line pressure ports 36b and 36c through which line pressure is guided, and oil chambers 21 and 22 on both sides of the servo piston 5 of the hydraulic cylinder 20 via oil passages 37 and 38, respectively. Line pressure supply port 3
6a and 36d are provided. When the line pressure is not supplied from the manual valve 35 to the control port 36e (the lower side in the figure), the line pressure is supplied to the line pressure supply ports 36a and 36a.
The oil is introduced from 6d into oil chambers 21 and 22 on both sides of the servo piston 5 of the hydraulic cylinder 20 through oil paths 37 and 38, respectively. Further, when the line pressure is supplied from the manual valve 35 to the control port 36e (upper state in the figure), the line pressure ports 36b and 36c are closed, and the oil chambers 21 and 22 on both sides of the servo piston 5 of the hydraulic cylinder 20 are closed. Cut off the introduction of line pressure.

The oil chamber 21 of the servo piston 5 of the hydraulic cylinder 20 is a high-side servo piston chamber, and the oil chamber 22 is a low-side servo piston chamber.

Next, the operation will be described.

The shift control valve 25 in the figure is in a state where the input spool valve body 27 is driven to the right side in the figure via the pinion 7 of the step motor in response to a gear ratio command from a controller (not shown). By this drive, the spool valve element 2
7, the line pressure port 25a is communicated only with the port 25c by the groove 27a.
Is introduced into the oil chamber 21 of the servo piston 5, and the power roller 1 is offset downward with respect to the input / output disks 2, 3 via the servo piston 5 and the trunnion 4,
By this offset, the power roller 1 naturally tilts in the direction corresponding to the speed ratio command to change the tilt angle (speed ratio).

On the other hand, the offset and the tilt of the power roller 1 are fed back from the precess cam 10 at the lower end of the rod of the servo piston 5 to the feedback sleeve valve body 28 of the speed change control valve 25 via the link 11 and the adjusting screw 13 and input. The sleeve valve element 28 is driven rightward in the figure following the spool valve element 27 for use. By this feedback drive, the sleeve valve body 28 is returned to the original relative position with respect to the input spool valve body 27, and the line pressure port 25a is connected to the port 25b and the port 25c, and the oil of the servo piston 5 of the hydraulic cylinder 20 is changed. Room 21,
22, a line pressure is introduced to the input / output disk 2 of the power roller 1 via the servo piston 5 and the trunnion 4.
The offset with respect to 3 is set to 0, whereby the tilt angle (speed ratio) corresponding to the speed ratio command is maintained.

The gear ratio control is performed as described above. On the other hand, in such a transmission, when the vehicle is left for a long period of time, the oil chambers 21 and
Air may accumulate in 22 and affect gear ratio control if it does, but is eliminated when the engine is started.

That is, when the engine is started (the manual valve 35 is set in the parking range), the line pressure guided to the valve device 36 is supplied from the line pressure supply ports 36a and 36d via the oil passages 37 and 38, respectively. Then, the air introduced into the oil chambers 21 and 22 of the servo piston 5 of the hydraulic cylinder 20 is introduced, and the air accumulated in the oil chambers 21 and 22 is quickly discharged by the introduction of the line pressure.

For this reason, even if the vehicle starts running immediately after the engine is started at a low temperature and enters the gear ratio control while the viscosity of the oil is high, the hydraulic pressure is not changed until the gear ratio control is started in a state after the engine has been left for a long time. Since the air in the oil chambers 21 and 22 of the servo piston 5 of the cylinder 20 is quickly discharged, a good shift response is obtained by the hydraulic pressure supply control by the shift control valve 25, and a good gear ratio control is secured. The start is performed immediately after the low temperature start.

When the manual valve 35 is set to a position other than the parking range, the line pressure supply ports 36a and 36d of the valve device 36 are shut off.

The groove 27a of the input spool valve body 27 of the transmission control valve 25 allows the openings 28b and 28c of the feedback sleeve valve body 28 to communicate with the opening 28a at the same time. 20
In order to introduce the line pressure into both oil chambers 21 and 22 during non-shift control, the servo piston 5 is formed so as to be introduced into at least one of the oil chambers 21 and 22 of the servo piston 5.

For this reason, when the engine is started and the line pressure is supplied to the shift control valve 25, the hydraulic cylinder 20 is also driven by the line pressure introduced from the shift control valve 25 as well as the line pressure from the valve device 36. The air accumulated in the oil chambers 21 and 22 of the servo piston 5 is discharged. Therefore, the air in the oil chambers 21 and 22 is reliably discharged.

The line pressure is always at least one of the oil chambers 21 and 2 of the servo piston 5 of the hydraulic cylinder 20.
2, even if the pressure in the oil chambers 21 and 22 decreases during traveling or the like and bubbles are generated, the bubbles can be quickly discharged, and the speed ratio controllability by such bubbles can be improved. Is prevented from deteriorating.

In addition, the air in the oil chambers 21 and 22 is discharged by introducing line pressure from the valve device 36,
Groove 2 of input spool valve body 27 of shift control valve 25
Both of them may be provided for discharging the air in the oil chambers 21 and 22 by 7a, but only one of them may be provided.

FIG. 2 shows another embodiment, in which a valve device 60 for introducing line pressure into the oil chambers 21 and 22 is mechanically linked to the manual valve 35.

In this case, a valve device 60 is provided in front of the manual valve 35, and the spool 61 of the valve device 60 is operated by the operation of the spool 39 of the manual valve 35. The upper side in the figure shows the position of the parking range of the manual valve 35,
The lower side shows the position of the reverse range of the manual valve 35.

When the spool 39 of the manual valve 35 is moved to the position of the parking range, the spool 61 of the valve device 60 is pushed to the upper position in the figure against the spring 62, and the line pressure ports 36b and 36c are Rooms 21, 22
Are connected to the line pressure supply ports 36a and 36d connected to the first and second lines. Therefore, when the manual valve 35 is in the parking range, the line pressure is reduced to the line pressure supply port 36.
a, 36d through the oil passages 37, 38 to the hydraulic cylinder 2
0 is introduced into the oil chambers 21 and 22 of the servo piston 5.

When the spool of the manual valve is moved to a position other than the parking range, the spool 61 of the valve device 60 is returned to the lower position in the figure by the spring 62, the line pressure ports 36b and 36c are closed, and the hydraulic pressure is reduced. The introduction of line pressure to the oil chambers 21 and 22 of the servo piston 5 of the cylinder 20 is shut off.

According to this, the hydraulic circuit is simplified.

FIG. 3 shows another embodiment, in which an input valve element 41 responding to a speed ratio command of a speed change control valve 40 is a sleeve valve element, and the offset and inclination of the power roller 1 are provided inside the sleeve valve element. A feedback spool valve element 42 that responds to rolling is accommodated.

In this case, the line pressure port 25a, each port 25b,
25c are provided with openings 41a, 41b, 41c.
The lands 42b and 42c corresponding to the lands 1b and 41c, and the openings 41b and 41c are formed between the lands 42b and 42c.
1a is provided with a groove 42a which can be communicated at the same time.

If the width of the groove 42a is A and the length between the open ends of the openings 41b and 41c is B, then A
> B. The other configuration is the same as that of the first embodiment.

According to this, the driving direction of the input sleeve valve element 41 by the speed ratio command and the feedback direction from the precess cam 10 to the feedback spool valve element 42 by the offset and tilting of the power roller 1 are the first direction. Although the embodiment is the opposite, the same operation is obtained.

FIG. 4 shows another embodiment, in which a link 50 for synthesizing an input amount of a gear ratio command and a feedback amount due to offset and tilt of the power roller 1 is provided. The spool valve element 52 is provided in response to the operation of the link 50.

The spool valve body 52 has a land 52a corresponding to the line pressure port 25a of the transmission control valve 51, a groove 52b capable of connecting the port 25b to the line pressure port 25a, and a port 25c communicating with the line pressure port 25a. And a possible groove 52c is provided.
Assuming that the width of A is A and the width of the opening of the land pressure port 25a is B, A> B is set. In other words, the line pressure is always introduced into at least one of the oil chambers 21 and 22 of the servo piston 5 of the hydraulic cylinder 20, and the line pressure is introduced into both the oil chambers 21 and 22 during non-shift control. ing.

The link 50 has a spool valve body 52 at the center.
The pin 11 is connected to a shaft end of the motor, and one end is connected to a rack bar 53 driven by being engaged with the pinion 7 of the step motor, and the other end is adjusted to a link 11 which is responsive to the precess cam 10 at the lower end of the rod of the servo piston 5. Screw 1
3 is abutted. The center of the link 50 is the spool valve element 5
2 is urged by a spring 54 to the left in the figure.

When the rack bar 53 is driven to the left side in the figure by the pinion 7 of the step motor, the link 50 is driven around the adjustment screw 13 as a fulcrum, and the spool valve body 52 is driven to the left side in the figure. At this time, the offset and the tilt of the power roller 1 are fed back, and when the adjusting screw 13 is moved to the right side in the figure, the link 50 is driven with the rack bar 53 side as a fulcrum, and the spool valve body 52 is returned to the right side in the figure. Returned to position. The other configuration is the same as that of the first embodiment.

According to this, the structure of the shift control valve 51 is simplified.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention.

FIG. 2 is a sectional view of a valve device and a manual valve portion according to another embodiment.

FIG. 3 is a cross-sectional view of a transmission control valve according to another embodiment.

FIG. 4 is a cross-sectional view of a transmission control valve according to another embodiment.

FIG. 5 is a sectional view of a main part showing a general structure of a toroidal type continuously variable transmission.

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Power roller 2 Input disk 3 Output disk 4 Trunnion 5 Servo piston 7 Pinion 10 Precess cam 11 Link 13 Adjustment screw 14 Eccentric shaft 20 Hydraulic cylinder 21, 22 Oil chamber 25 Shift control valve 25a Line pressure port 25b, 25c port 27 Input spool Valve body 27a Groove 27b, 27c Land 28 Feedback sleeve valve body 28a, 28b, 28c Opening 35 Manual valve 35b Reverse range port 35c Valve port 35d Line pressure port 35e Forward range port 36 Valve device 36a, 36d Line pressure supply port 36b , 36 Line pressure port 36e Control port 37, 38 Oil passage 39 Spool 40 Transmission control valve 41 Input sleeve valve body 41a, 41b, 41c Opening 42 Feedback Pool valve body 42a groove 42b, 42c lands 50 link 51 the shift control valve 52 the valve spool 52a lands 52b, 52c Groove 60 valve 61 spool 62 Spring

Claims (7)

[Claims] 1. A power roller sandwiched between an input / output disk and rotatably and tiltably supported, a servo piston capable of moving the power roller in the tilt axis direction, and a servo in response to a speed ratio command. A shift control valve that controls the supply of pressure to both piston chambers, and by shifting the power roller so that the rotation axis is offset from the position where the rotation axis intersects the input / output disk axis during gear shifting, the power roller is moved. By tilting the gear ratio toward the command value and feeding back the tilt and movement of the power roller to the speed change control valve, when the tilt angle of the power roller becomes an angle corresponding to the command value of the speed ratio, In a toroidal-type continuously variable transmission that maintains a power roller at a position of offset 0, the two servo piston chambers are in a parking state. Hydraulic control system of the toroidal type continuously variable transmission which is characterized in that so as to introduce the line pressure. 2. A power roller sandwiched between an input / output disk and rotatably and tiltably supported, a servo piston capable of moving the power roller in the tilt axis direction, and a servo in response to a speed ratio command. A shift control valve that controls the supply of pressure to both piston chambers, and by shifting the power roller so that the rotation axis is offset from the position where the rotation axis intersects the input / output disk axis during gear shifting, the power roller is moved. By tilting the gear ratio toward the command value and feeding back the tilt and movement of the power roller to the speed change control valve, when the tilt angle of the power roller becomes an angle corresponding to the command value of the speed ratio, In a toroidal-type continuously variable transmission that maintains a power roller at a position of offset 0, the two servo piston chambers are in a parking state. Hydraulic control system of the toroidal type continuously variable transmission, characterized in that a valve means for introducing the line pressure. 3. The valve means according to claim 2, wherein said valve means introduces line pressure into both chambers of said servo piston when a manual valve interlocking with a select lever for selecting a travel range is in a parking position. The hydraulic control device for a toroidal-type continuously variable transmission according to claim 2, wherein the introduction of line pressure is interrupted. 4. The hydraulic control device for a toroidal-type continuously variable transmission according to claim 3, wherein the valve means is mechanically linked to a manual valve. 5. A power roller sandwiched between an input / output disk and rotatably and tiltably supported, a servo piston capable of moving the power roller in the tilt axis direction, and a servo responsive to a speed ratio command. A shift control valve that controls the supply of pressure to both piston chambers, and by shifting the power roller so that the rotation axis is offset from the position where the rotation axis intersects the input / output disk axis during gear shifting, the power roller is moved. By tilting the gear ratio toward the command value and feeding back the tilt and movement of the power roller to the speed change control valve, when the tilt angle of the power roller becomes an angle corresponding to the command value of the speed ratio, In the toroidal-type continuously variable transmission configured to keep the power roller at the offset 0 position, the transmission control valve always has a line pressure port for controlling a transmission ratio. The structure communicates with at least one of a port communicating with the high-side servo piston chamber for offsetting the power roller in the direction of shifting to the a side and a port communicating with the low-side servo piston chamber for offsetting the power roller in the direction of shifting to the low side. A hydraulic control device for a toroidal-type continuously variable transmission, comprising: 6. The speed change control valve communicates with a spool responsive to a speed ratio command simultaneously with a line pressure port located on both sides thereof and a port communicating with a high side servo piston chamber and a port communicating with a low side servo piston chamber. The hydraulic control device for a toroidal-type continuously variable transmission according to claim 5, which has a possible groove. 7. The speed change control valve has a spool responsive to tilting and movement of a power roller inside a sleeve responsive to a speed ratio command, and a line pressure port is connected to the spool via a sleeve. The hydraulic control device for a toroidal-type continuously variable transmission according to claim 5, further comprising a groove that can simultaneously communicate with a port that communicates with the side servo piston chamber and a port that communicates with the low servo piston chamber.