JPH0727213A - Transmission ratio control method for toroidal continuously variable device - Google Patents

Abstract

PURPOSE:To speedily control the control pressure of operation oil to be supplied to a hydraulic mechanism, and effectively suppress loss of hydraulic pressure. CONSTITUTION:A transmission control device for a Toroidal continuously variable transmission has a plurality of power rollers 35 arranged between an input disc 34 and an output disc 33, a support means 44 which rotatably supports the power rollers 35, and a hydraulic mechanism composed of a hydraulic piston 52 which moves the support means in its axial direction. In such a transmission control device, a relief valve 98 is provided for setting a relief pressure of operation oil to be a constant value, which operation oil is relieved from transmission ratio control valves 62a, 62b operated to control supply and discharge of the operation oil in respect to the hydraulic mechanism.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear ratio control device for a toroidal type continuously variable transmission in which a plurality of power rollers are installed between an input disk and an output disk.

[0002]

2. Description of the Related Art A toroidal type continuously variable transmission has an input disk to which a driving torque is input from an engine of an automobile, as disclosed in, for example, Japanese Patent Laid-Open No. 1-135958.
A pair of power rollers arranged between an output disc that outputs drive torque to the drive wheels, a hydraulic mechanism that displaces a support member that rotatably supports the power rollers in the axial direction thereof, and the hydraulic mechanism. And a gear ratio control valve that supplies hydraulic oil to the. Then, the hydraulic mechanism is operated by the hydraulic oil supplied from the gear ratio control valve to change the tilt angle of the power roller to adjust the gear ratio.

In the toroidal type continuously variable transmission described in the above publication, hydraulic oil supplied from an input port formed in a sleeve of a gear ratio control valve and leaked through an output port is lubricated to a communication hole of a spool and lubricated. Lubricating oil is supplied to the toroidal transmission unit via a relief passage formed of an oil port.

[0004]

When the hydraulic oil that is relieved from the gear ratio control valve through the relief passage is used as the lubricating oil as described above, the hydraulic oil is utilized without waste. Although it has the advantage of being able to effectively lubricate the necessary parts, the relief amount of the hydraulic oil fluctuates under the influence of input torque, speed change ratio, temperature change, etc., which causes the following disadvantages.

That is, there is a problem that the piston pressure of the hydraulic mechanism cannot be quickly controlled when the reverse drive torque acts in a state where the amount of hydraulic oil in the relief passage is extremely small. Further, since it is necessary to set the line pressure of the hydraulic oil supplied to the hydraulic mechanism to a high level in anticipation of the variation in the relief amount of the hydraulic oil, there is a problem that the loss of hydraulic pressure increases.

The present invention has been made in order to solve the above-mentioned problems, and it is possible to quickly control the control pressure of the hydraulic oil supplied to the hydraulic mechanism and effectively suppress the loss of hydraulic pressure. An object of the present invention is to provide a gear ratio control device for a toroidal type continuously variable transmission that can achieve the above.

[0007]

SUMMARY OF THE INVENTION The present invention is directed to a plurality of power rollers installed between an input disk and an output disk, a support member for rotatably supporting the power rollers, and an axis line of the support member. In a gear ratio control device for a toroidal type continuously variable transmission having a hydraulic mechanism that moves in a direction, a relief pressure of the hydraulic oil that is relieved from a gear ratio control valve that controls the supply and discharge of hydraulic oil to the hydraulic mechanism is a constant value. The relief valve is set to.

[0008]

According to the present invention having the above-described structure, the pressure of the hydraulic oil that is relieved from the gear ratio control valve during operation of the hydraulic mechanism is maintained at a constant value by the relief valve, and is in a relief state when the reverse drive torque is applied. The pressure of the hydraulic fluid at the port will rise rapidly. Further, the line pressure of the hydraulic oil is always set to the optimum value based on the relief pressure of the hydraulic oil held at the constant value.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a schematic structure of a transmission of an automobile having a valve structure of a toroidal type continuously variable transmission according to an embodiment of the present invention. This transmission has first and second power transmission paths 3 and 4 which are switched by a path switching clutch 2 connected to the output side of the engine 1. The first power transmission path 3 outputs the engine output to the speed reducer 7
In this embodiment, the power is transmitted from the torque converter 5 to the wheel side via the forward / reverse switching device 6 and the speed reducer 7. The second power transmission path 4 transmits the engine output to the wheels via the toroidal type continuously variable transmission 8.

The torque converter 5 has its input shaft 5
pump cover 11 connected to a and this pump cover 11
A pump impeller 12 integrally formed with the turbine, a turbine liner 13 installed so as to face the pump impeller 12, and a hollow fixed shaft 15 between the turbine liner 13 and a one-way clutch 16.
And a stator 14 attached thereto. And
The input shaft 5a is connected to the output shaft of the engine 1, and the turbine shaft 17 serving as the output shaft of the torque converter 5 is connected to the turbine liner 13.
The space inside the pump cover 11 is filled with oil as a working fluid. A hollow rotary shaft 18 is connected to the pump impeller 12, and an oil pump 19 is attached to the rear end of the shaft 18.

The speed reducer 7 includes a turbine shaft 17
And two planetary gear mechanisms 20 and 21 for backward and forward movement, which are arranged coaxially with each other, and both planetary gear mechanisms 20 and 2 are provided.
The sun gear 22 commonly used by No. 1 is the turbine shaft 1
It is connected to 7. The reverse planetary gear mechanism 20 is
It is a single pinion type, and the rotation of the sun gear 22 is transmitted to the ring gear 25 via the pinion 24 supported by the carrier 23. The carrier 23 is connected to the hollow fixed shaft 15 and fixed to the casing 10. The ring gear 25 is connected to the output shaft 30 of the transmission via the reverse clutch 6a.

On the other hand, the forward planetary gear mechanism 21 is of a double pinion type so that the rotation of the sun gear 22 is transmitted to the ring gear 28 via the inner pinion 26 and the outer pinion 27 supported by the carrier 23. Has become. The ring gear 28 is connected to the output shaft 30 via a forward clutch 6b and a one-way clutch 29.

The reverse clutch 6a and the forward clutch 6b constitute a forward / reverse switching device 6. When the reverse clutch 6a is engaged, the input from the turbine shaft 17 is transmitted to the output shaft 30 of the transmission via the reverse planetary gear mechanism 20.
When the forward clutch 6b is engaged, the input from the turbine shaft 17 is transmitted to the output shaft 30 via the forward planetary gear mechanism 21.

On the other hand, the toroidal type continuously variable transmission 8 of the second power transmission path 4 includes a pair of continuously variable transmission units 31, 32.
Both continuously variable transmission units 31, 3
2 is the output shaft 30 at a position adjacent to the speed reducer 7.
It is placed on top. The continuously variable transmission unit 31, 3
Reference numeral 2 has a pair of disks 33 and 34 which are spaced apart from each other in the axial direction, and a pair of power rollers 35 which are arranged between these disks 33 and 34 and are in sliding contact with both disks 33 and 34. is doing. Both power rollers 35
Are installed to face each other with the output shaft 30 interposed therebetween.

One disk (output disk) 33 of the pair of disks is fixed to the output shaft 30,
The other disc (input disc) 34 is the output shaft 30.
It is supported so as to be rotatable relative to and axially movable. The power roller 35 is configured such that the tilt angle θ is changed by a hydraulic mechanism described later, and the gear ratios of the toroidal type transmission units 31 and 32 are changed accordingly.

That is, the gear ratio when the rotation of the input disk 34 is transmitted to the output disk 33 via the power roller 35 is as follows.
Is set in accordance with the ratio of the radius Ri of the portion slidingly contacting the disk to the radius Ro of the portion slidingly contacting the output disk 33, so that when the power roller 35 tilts and the sliding contacting point is displaced,
In response to this, the toroidal type continuously variable transmission unit 3
The gear ratios of 1 and 32 are changed.

The structure of the transmission units 31, 32 of the toroidal type continuously variable transmission 8 will be described with reference to FIG. Output disc 33 of one transmission unit 31
Is spline-fitted to the output shaft 30 of the transmission, and is positioned by a ring-shaped positioning member 36 provided on the output shaft 30 in the bearing 37.
It is rotatably supported by the transmission case 38 via. The output disk 3 of the other transmission unit 32
3 is positioned by a bearing 37 that is locked to a step formed on the output shaft 30 of the transmission.

An input cam 38, which is supported so as to be rotatable relative to the input disks 34 constituting the transmission units 31 and 32, is disposed between the input disks 34. The input cam 38 and the input disk 34
Between the cam roller 40 held by the retainer 39 and
Is installed. The cam roller 40 contacts the cam surfaces formed on the input disk 34 and the input cam 38, respectively, and transmits the driving torque input to the input cam 38 to the output disk 33 via the input disk 34 and the power roller 35. Is configured to.

Further, the support member 4 for supporting the input disk 34 of the transmission unit 32 and the input cam 38.
An urging member 42, which is a disc spring for urging the input disks 34 of both transmission units 31 and 32 toward the output disk 33, is installed between the first and second transmission units 31 and 32.
A preload pressure is applied between the input disk 34 and the output disk 33 according to the urging force of.

Further, as shown in FIG. 3, the transmission units 31, 32 are provided with a trunnion 44 having an eccentric shaft 43 for rotatably supporting the power roller 35. A shaft member 45 projecting to the side is attached. And the trunnion 44
Has its upper end supported by the upper surface of the transmission casing 38 via a spherical bush 46 and a connecting member 47 supporting the spherical bush 46, and its lower end has a spherical bush 48.
It is supported by a partition wall 51 provided at the lower end of the transmission case 38 via a connecting member 49 and a support shaft 50 that support this.

Inside the partition wall 51, a hydraulic cylinder 52 for operating the trunnion 44 is provided.
The hydraulic cylinder 52 has a pair of upper and lower hydraulic pressures defined by a pair of upper and lower pistons 53 and 54 supported by the shaft member 46 of the trunnion 44 and a wall plate 55 located between the pistons 53 and 54. It has chambers 56 and 57. When hydraulic oil is introduced into the upper hydraulic chamber 56,
When the trunnion 44 is pushed up by the upper piston 53 and hydraulic oil is introduced into the lower hydraulic chamber 57, the trunnion 44 is pushed down by the lower piston 54,
With this, the power roller 35 is tilted.

At the central portion of the upper connecting member 47, a positioning hole is formed in which a supporting shaft 58 projecting from the transmission case 22 and a supporting member 59 fitted onto the supporting shaft 58 are installed. In addition, a positioning hole 61 is formed in the central portion of the lower connecting member 49, in which the spherical bearing 60 fitted on the support shaft 50 is installed.

Hydraulic chambers 56 and 57 of the hydraulic cylinder 52.
The structure of the gear ratio control valve 62 that controls the gear ratio by controlling the supply and discharge of hydraulic oil will be described with reference to FIG. The gear ratio control valve 62 is used for the hydraulic cylinder 5
2 has a valve body 64 provided below the installation portion, a sleeve 65 fitted in the valve body 64, and a spool 66 slidably supported in the sleeve 65. ing. At one end of the spool 66, a spring 67 that constitutes a control actuator, a rotating member 68, a pin member 69,
A stepping motor 70 is provided, and mechanical feedback means 71 is installed at the other end of the spool 66.

The sleeve 65 has a main port 72, which is in constant communication with the source pressure receiving port P1, the first output port P2, and the second output port P3, which are formed in the valve body 64. And the first port 73
And a second port 74 are formed. Further, a spacer 83 having a communication hole 84 communicating with the drain port P4 formed in the valve body 64 is arranged at the tip end portion of the sleeve 65, that is, at a position close to the installation portion of the feedback means 71. The front and rear ends of the spacer 83 are sealed by oil seals S.

Further, the spool 66 is formed with an annular groove 75 which is in constant communication with the main port 72, and first and second land portions 76 and 77 located on the left and right sides thereof. The first and second land portions 76 and 77 respectively have the first and second ports 73 and 77 during non-shifting in which neither upshifting nor downshifting is performed.
It is configured to close 74. The spool 66
A drain passage 78 for hydraulic relief is formed in the center of the spacer 8 and the spacer 8 is provided near the tip of the drain passage 78.
A lead-out hole 79 for leading out hydraulic oil to the relief port P4 via the three communication holes 84 is formed.

A rotary member 68 is attached to the drive shaft of the stepping motor 70, and a collar 85 is screwed to the tip of the rotary member 68. A pin member 69 is locked to the collar 85, and both ends of the pin member 69 are locked to grooves (not shown) formed in the valve body 64, whereby the collar 85 is locked.
Is prevented from rotating. Then, when the rotating member 68 is rotationally driven by the stepping motor 70, the collar 85 moves in the axial direction thereof, and along with this, the sleeve 6 via the pin member 69.
5 is configured to be slidably displaced in the axial direction.

In response to the sliding displacement of the sleeve 65, the main port 72 of the sleeve 65 passes through the groove 75 of the spool 66 and the first port 73 of the valve body 65.
Alternatively, the source pressure receiving port P1 is communicated with the second port 74.
The shift control is executed by discharging the hydraulic oil therein to the first output port P2 or the second output port P3.

The feedback means 71 is provided with a shaft member 45 protruding from one trunnion 44, a recess cam 80 attached to the lower end of the shaft member 45, and a ball bearing portion provided at the tip of the speed ratio control valve 62. And 81. The precess cam 80 is composed of an eccentric cam having a cam surface 82 with a downward constriction formed on the peripheral surface thereof.
5 is attached at a position offset from the center part to one side. The ball bearing 81 provided at the tip of the spool 66 is pressed against the cam surface 81 of the recess cam 80 by the urging force of the spring 67 installed in the sleeve 65 of the gear ratio control valve 62. There is.

A gear ratio control device for controlling the gear ratio by controlling the supply and discharge of hydraulic oil to and from the hydraulic cylinder 52 is shown in FIG.
As shown in, the forward gear ratio control valve 62a, the reverse gear ratio control valve 62b, the line pressure control valve 86, the forward / reverse switching valve 87, the clutch pressure switching valve 88, and the clutch pressure control valve. 89 and are provided. Further, the above gear ratio control device includes various solenoid valves 90 to 94, a reducing valve 96 for secondary pressure reduction, a relief valve 97 for oil cooler protection, and the both gear ratio control valves 6
A relief valve 98 for setting the relief pressure of 2a and 62b to a constant value is provided.

The hydraulic oil discharged from the oil pump 19 is regulated to a predetermined pressure by the line pressure control valve 86, and then is passed through one of the both gear ratio control valves 62a and 62b and the forward / reverse switching valve 87. Is supplied to the hydraulic chambers 56 and 57 of the hydraulic cylinder 52. Further, the hydraulic oil is supplied to the reverse clutch 6a or the forward clutch 6 via the clutch pressure switching valve 88 and the clutch pressure control valve 89.
b is supplied to one side of the valve b, is supplied as a pilot pressure to the line pressure control valve 86 and the clutch pressure control valve 91 through the reducing valve 96 and the solenoid valves 91 and 92, and is further supplied through the oil cooler 99. It is supplied to the lubrication part.

In the above configuration, when the stepping motor 70 is rotationally driven at an angle corresponding to the target tilt angle (target gear ratio) in response to a control signal output from a control unit (not shown) during gear shifting, this rotation angle The sleeve 65 moves in the axial direction by an amount corresponding to. As a result, the main port 72 of the sleeve 65 is
6 is communicated with the first port 72 or the second port 74 of the valve body 65 through the groove 75, whereby hydraulic oil is supplied to the predetermined hydraulic chambers 56 and 57, and the power roller 35 is displaced to the target tilt angle. To do.

For example, when shifting up, when the stepping motor 70 rotates forward by a predetermined angle in response to the control signal, the sleeve 65 moves to the tip side, that is, the side where the feedback means 71 is installed. As a result, the main port 72 communicates with the first port 73 via the groove 75, and the hydraulic oil in the source pressure receiving port P1 is transferred to the first output port P.
2 and the second output port P3 communicates with the drain passage 78, so that the hydraulic pressure in the second output port P3 is reduced.

By operating the hydraulic cylinder 52 in accordance with the operating hydraulic pressure, the trunnion 44 that supports the power roller 35 is driven up and down, and the power roller 35 is tilted accordingly and is toroidal type. The continuously variable transmission 6 shifts to the speed increasing side. Further, the relief pressure of the hydraulic oil reduced through the drain passage 78 is held at a constant value by the relief valve 98.

On the other hand, at the time of downshifting, the stepping motor 70 reversely rotates by a predetermined angle according to the control signal, and the sleeve 65 moves to the base end side, that is, the installation side of the stepping motor 70. As a result, the main port 72 communicates with the second port 74 via the groove 75, the hydraulic oil in the source pressure receiving port P1 is output to the second output port P3, and the first output port P2 is connected to the drain passage. By communicating with 78, the hydraulic pressure in the first output port P2 is reduced. At this time, the relief valve 98 maintains the relief pressure at a constant value.

The hydraulic cylinder 52 operates in accordance with the operating hydraulic pressure, whereby the trunnion 44 is driven up and down in the opposite direction to the upshift.
Along with this, the power roller 35 tilts and the toroidal type continuously variable transmission 6 shifts to the deceleration side. At the time of this downshift, the sleeve 65 is biased toward the tip end side by the spring 67, so that the biasing force causes the sleeve 65 to move quickly and the shift responsiveness is ensured.

When the trunnion 44 and the shaft member 45 move up and down and rotate in response to the tilt of the power roller 35, the precess cam 80 moves up and down and rotates accordingly. The ball-shaped bearing portion 81 provided at the tip of the spool 66 is pushed by the cam surface 82 according to the elevation and rotation of the precess cam 80, and the spool 66 is slid in the same direction as the moving direction of the sleeve. It

When the tilt angle of the power roller 35 reaches the target tilt angle, the movement amount of the spool 66 becomes equal to the movement amount of the sleeve 65, and the main port 72 is moved.
Then, the communication with the first port 73 or the third port 74 is blocked. As a result, the supply of hydraulic oil to the hydraulic chambers 56 and 57 is stopped, the change of the tilt angle is prevented, and the power roller 35 is held at the target tilt angle.

The relief pressure relieved from the gear ratio control valve 62 is controlled by the gear ratio control device having the gear ratio control valve for controlling the supply and discharge of the hydraulic oil to the hydraulic mechanism including the hydraulic piston 52 as described above. Relief valve 98
With the provision of the above, it is possible to always quickly increase the piston pressure, that is, the control pressure when the operating state of the transmission changes and the drive torque is reversed.

That is, in the case where the hydraulic oil that is relieved from the gear ratio control valve 62 is discharged to the speed change portion as lubricating oil or directly relieved to the oil pan, it is in a relief state before the speed change. Since the piston pressure in the hydraulic chamber may drop extremely, when the transmission changes from the driving state to the reverse driving state or from the reverse driving state to the driving state and the driving torque is reversed, It will take some time to raise the piston pressure to the required pressure.

On the other hand, when the relief valve 98 is provided to set the relief pressure of the gear ratio control valve to a constant value as described above, the piston pressure of the hydraulic chamber in the relief state is more than necessary. Since it is possible to prevent the piston pressure in the hydraulic chamber from being rapidly increased at the time of reversing the driving torque, it is possible to always obtain excellent responsiveness.

Further, since it is not necessary to take a means of setting the line pressure in advance to a high value in consideration of the change in the relief pressure due to the change in the amount of hydraulic oil that is relieved from the gear ratio control valve 62, the line pressure is not required. Can be set to an optimum value to effectively prevent the loss of hydraulic pressure.

For example, the line pressure PL required to execute the shift control at the time of increasing the speed is the piston pressure PU on the high pressure side.
The high-pressure side piston pressure PU is set to a value larger than the sum of the low-pressure side piston pressure PD and the difference ΔP between the high-pressure side piston pressure PU and the low-pressure side piston pressure PD. There is a need. Further, since the low-pressure side piston pressure PD is always higher than the relief pressure PR of the hydraulic oil that is relieved from the gear ratio control valve 62, when the relief pressure PR fluctuates and becomes a large value, this Accordingly, the high-pressure side piston pressure PU must also be increased.

Therefore, in the case where the relief pressure PR of the hydraulic oil changes according to the operating condition, etc., the line pressure PL is set to a high value in advance in consideration of this, so that the line pressure has a margin. It is necessary to have it. On the other hand, when the relief pressure is set to a constant value as described above, it is not necessary to consider the margin due to the fluctuation of the relief pressure, so by setting this value to the minimum required value, It is possible to suppress the loss of hydraulic pressure.

Further, in the above embodiment, as shown in FIG. 4, the spacer 83 is installed at the tip of the sleeve 65 of the gear ratio control valve 62, and the relief lead-out hole 79 is formed in the spacer 83. Leakage of hydraulic oil can be effectively prevented without causing a drive loss of the motor 70. That is, since the working oil is relieved from the outlet hole 79 provided in the spacer 83 formed separately from the sleeve 65 to the drain port P4 through the communication hole 84, this relief oil is used to relieve the sleeve 65. It is possible to reliably prevent leakage to the base end side of the spool 66, that is, the installation side of the stepping motor 70, passing through between the spool 66 and the spool 66.

Therefore, it is possible to prevent the hydraulic oil from leaking out without providing a seal member at the connecting portion between the speed ratio control valve 62 and the stepping motor 70. Therefore, as in the case where the seal member is provided at this portion, a seal is provided. It is possible to prevent the situation in which the driving resistance of the stepping motor 70 increases due to the presence of the member, and thereby it is possible to suppress the waste of the driving torque.

[0046]

As described above, the present invention provides a gear ratio control device having a gear ratio control valve for controlling supply and discharge of hydraulic oil to and from a hydraulic mechanism including a hydraulic piston and the like. Since the relief valve for controlling the relief pressure of the hydraulic oil is provided, it is possible to prevent the delay in the response of the shift control due to the piston pressure of the hydraulic mechanism being lowered more than necessary. Therefore, when the reverse drive torque is applied during the operation of the transmission, the piston pressure in the hydraulic chamber can always be rapidly raised to improve the response of the shift control.

Further, since it is not necessary to take a means of setting the line pressure to a high value in advance in consideration of the change in the relief pressure due to the change in the amount of hydraulic oil relieved from the gear ratio control valve, the line pressure can be reduced. There is an advantage that it is possible to effectively prevent loss of hydraulic pressure by setting the optimum value to the minimum required value.

[Brief description of drawings]

FIG. 1 is a schematic explanatory diagram showing an overall configuration of a transmission including a gear ratio control device for a toroidal type continuously variable transmission according to an embodiment of the present invention.

FIG. 2 is a side sectional view showing a specific structure of the toroidal type continuously variable transmission.

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

FIG. 4 is a sectional view showing a configuration of a gear ratio control valve.

FIG. 5 is a hydraulic circuit diagram showing a configuration of a shift control device.

[Explanation of symbols]

 8 Toroidal Type Continuously Variable Transmission 33 Output Disc 34 Input Disc 35 Power Roller 44 Trunnion (Supporting Member) 52 Hydraulic Mechanism (Hydraulic Piston) 62 Gear Ratio Control Valve 98 Relief Valve

Claims (1)

[Claims] 1. A plurality of power rollers installed between an input disk and an output disk, a support member for rotatably supporting the power rollers, and a hydraulic mechanism for moving the support members in the axial direction thereof. In the gear ratio control device for the toroidal type continuously variable transmission, which has the relief valve for setting the relief pressure of the hydraulic oil that is relieved from the gear ratio control valve that controls the supply and discharge of the hydraulic oil to the hydraulic mechanism to a constant value A gear ratio control device for a toroidal type continuously variable transmission characterized by the above.