JPH0539847A - Speed change control device for toroidal continuously variable transmission - Google Patents

Abstract

PURPOSE:To provide a device to stabilize speed change control by improving the sensitivity of a speed change control valve to actuate the power roller actuator of a toroidal speed change mechanism at high speed revolutions for an improvement in damping effect. CONSTITUTION:In the case where a speed change control valve 70 is controlled through a feedback (F/B) system composed of a precession cam 121, a link 122 and a spool 73b which interlock with the movement of a power roller, the control valve 70 actuates an actuator, and F/B control is executed so as to obtain a target speed change ratio. The control valve 70 is supplied with the line pressure of an oil passage 150 as speed change control pressure, which depends upon the number of input revolutions, and increases at high speed revolutions to heighten the sensitivity of the control valve. The damping effect at the high speed revolutions is therefore improved to stabilize the speed change control even in the case of high input revolving speed at which the power roller acts quickly. A valve being little in leakage can be used as the control valve 70.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift control device for a toroidal continuously variable transmission, and more particularly to a shift control device for improving controllability.

[0002]

2. Description of the Related Art A toroidal continuously variable transmission can be constructed by using a speed change mechanism having an input / output disk and a power roller arranged between them. The gear ratio can be continuously changed, and the power ratio can be continuously changed by offsetting the power roller with respect to the input / output disk and changing the contact position.

[0003]

[Problems to be Solved by the Invention] SAE Paper 901761 (19
(September 1960), a study on the gear ratio control in the half toroidal CVT was made. According to this, the swinging speed of the power roller, which corresponds to the gear shifting speed (gearing speed), is the disc rotation speed and the power roller. It is disclosed that it is determined according to the vector difference with the rotation speed of (Fig. 3). Here, it is understood that the disk rotation speed and the power roller rotation speed are proportional to the input rotation speed, and thus the shift speed is proportional to the input rotation speed. The above means that the responsiveness of the system changes depending on whether the rotation speed is high or low, and even if the gear ratio is the same, the power roller behaves quickly (swing) when the input rotation speed is high. Exercise) and try to shift gears.

On the other hand, focusing on the shift control valve, it can be configured to perform feedback control so that the target gear ratio is obtained in the gear ratio control, and this can operate the actuator for the power roller. When the control valve does not properly control the vibration of the power roller during shifting, undesired hunting or the like occurs, and the response of the system and the damping function, that is, the damping function corresponds to the toroidal CVT. Then, it is one of the important things when trying to improve the actual controllability. In particular, as described above, since the power roller behaves quickly when the input rotation speed is large, it is required that the vibration damping effect be larger than that at the low speed rotation. It is possible to stabilize the shift control.

An object of the present invention is to embody the above idea and to change the sensitivity of a speed change control valve of a toroidal continuously variable transmission according to an input speed to improve controllability and stabilize speed change control at high speed rotation. An object of the present invention is to provide a shift control device capable of achieving the above.

[0006]

According to the present invention, the following shift control device for a toroidal continuously variable transmission is provided. In a toroidal continuously variable transmission that has a power roller between the input / output disk and both disks, and operates the power roller by an actuator to perform a speed change, a hydraulic pressure supplied as a speed change control pressure to a speed change control valve that operates the actuator, A shift control device for a toroidal continuously variable transmission, which controls the input disc so that it is large when the rotation is high.

[0007]

In the toroidal continuously variable transmission, the power roller between the input and output disks is operated via the actuator to change the speed. The shift control device controls the hydraulic pressure supplied as a shift control pressure to the shift control valve that operates the actuator so as to depend on the input rotation speed and to be large at a high rotation speed. As a result, the sensitivity of the shift control valve can be changed depending on the input rotation speed, and the increase of the shift control pressure at high rotation brings about the increase of the sensitivity, and the damping effect can be enhanced at high speed to stabilize the shift control. It is possible to realize the above even with a control valve having a small leak amount.

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows the basic configuration of a toroidal continuously variable transmission having a toroidal transmission mechanism to which the embodiment apparatus according to the present invention can be applied, and FIGS. 2 to 5 are circuit diagrams of the shift control hydraulic system.

To explain the transmission train in the frame diagram of FIG.
Reference numeral 10 denotes a toroidal continuously variable transmission, in which torque from an engine (not shown) is transmitted through the torque converter 12 to the continuously variable transmission.
Entered in 10. The torque converter 12 includes a pump impeller 12a, a turbine runner 12b, a stator 12c, a lockup clutch 12d, an apply-side oil chamber 12e, a release-side oil chamber 12f, and the like.
4 penetrates.

The input shaft 14 is a forward / reverse switching mechanism 36.
The mechanism 36 includes a planetary gear mechanism 42, a forward clutch 44, a reverse brake 46, and the like. Planetary gear mechanism
The reference numeral 42 includes a ring gear 42b and a sun gear 42c that mesh with the respective double planetary gears.

The right end of the input shaft 14 is supported by a torque transmission shaft 16 arranged coaxially. In this example, a first continuously variable transmission mechanism (toroidal transmission mechanism) 18 and a second continuously variable transmission mechanism (toroidal transmission mechanism) 20 are arranged on the torque transmission shaft 16 in a tandem downstream of a transmission case 22. (Dual-cavity type). The body of the control valve system (Figs. 2 to 4) is arranged in the space indicated by reference numeral 64.

The first continuously variable transmission mechanism 18 has a pair of input disks 18a and output disks 18b whose opposing surfaces are toroidal curved surfaces and frictional contact between the opposing surfaces of these input / output disks and the torque transmission shaft 16 thereof. It is provided with a pair of power rollers 18c and 18d symmetrically arranged with respect to each other, a supporting mechanism for respectively tiltably supporting these power rollers, and a servo piston (see FIGS. 5 and 6) as a hydraulic actuator. Similarly, the second continuously variable transmission 20 also has input / output disks 20a and 20b having opposed surfaces of toroidal curved surfaces, a pair of power rollers 20c and 20d,
And a support mechanism thereof and a servo piston (see FIG. 5).

Continuously variable transmission mechanism 1 on the torque transmission shaft 16
8 and 20 are arranged in opposite directions so that the output discs 18b and 20b face each other, and are the input discs of the first continuously variable transmission mechanism 18.
18a is pressed toward the right side in the axial direction in the drawing by a loading cam device 34 that generates a pressing force according to the input torque that has passed through the torque converter 12. The device 34 has a loading cam 34a and through a thrust bearing 38 the shaft 16
Supported by. Input disk 20a of the second continuously variable transmission 20
Are pressed and urged toward the left side in the axial direction in the figure by the disc spring 40. Each input disk 18a, 20a is rotatably and axially movably supported by the transmission shaft 16 via ball splines 24, 26. In the above mechanism, each power roller is tilted by an operation described later so as to obtain a tilt angle according to the gear ratio, and the input rotation of the input disk is steplessly (continuously) changed and transmitted to the output disk. ..

The output disks 18b, 20b are the torque transmission shaft 16
The transmission torque is spline-coupled to the output gear 28 which is relatively rotatably fitted to the upper side, and the transmission torque is transmitted to the gear 30a coupled to the output shaft (counter shaft) 30 through the output gear 28. A torque transmission mechanism 32 is configured. Further, a gear 52 provided on the output shaft 30, a gear 56 provided on the output shaft 50, and an idler gear 54 that meshes with these gears, respectively.
It is assumed that the transmission mechanism 48 consisting of is provided and the output shaft 50 is connected to the propeller shaft 60.

The hydraulic control circuit for gear shift control for the transmission system is constructed as shown in FIGS. Here, FIG. 5 mainly shows the servo system, and FIGS. 2 to 4 show the control valve system, respectively. Reference numerals (a) to
(Y) means that the same reference numerals are connected on the circuit in the corresponding drawings.

2 to 5, a hydraulic control circuit includes a hydraulic cylinder of a hydraulic servo device for shifting which functions as a power roller actuator of a toroidal transmission mechanism, and a cylinder supply for performing a shift at a predetermined gear ratio by the cylinder operation. A shift control valve that adjusts and controls the hydraulic pressure (Fig. 4,
5) and other various valves and the like (FIGS. 2 to 4) are constituent elements.

That is, the circuit has a forward speed change control valve 70, a reverse speed change ratio command valve 80, and a forward / reverse switching valve 81 (FIG. 4), and a pressure regulator valve (line pressure regulating valve) 82, Manual valve 83, lock-up control valve
84, relief valve 85, accumulator control valve 86,
It has a forward clutch accumulator 87 and a reverse brake accumulator 88 (Fig. 2), and also has a constant pressure regulating valve 89, a pressure modifier valve 90, and an accumulator 9.
1, 92, a lockup solenoid 93, a line pressure solenoid 94 (each in FIG. 3), and the like. These are shown in Figures 2-4.
The oil pump (O / P) 95, which is connected to the engine and driven by the engine, and the oil pump capacity control room (O / P CON
T) 96, the forward clutch (F / C) 44, the reverse brake (R / B) 46, the apply-side oil chamber 12e and the release-side oil chamber 12f of the tokule converter 12, the lubricating circuit 97, and the oil cooler. 98 and the like are also connected as shown. Here, the oil pump 95 is a variable displacement vane pump. In the pump, the eccentric amount is reduced when the pressure acting on the cam ring becomes high, and the displacement is controlled so that the displacement becomes small.

Further, the forward speed change control valve 70, the reverse speed change ratio command valve 80, and the forward / reverse switching valve which are connected as shown in FIG.
The system of 81 is connected to the cylinder chamber in each cylinder 100 of the hydraulic servo system for shifting as shown in FIG. 5, that is, to the high (small gear ratio) side oil chamber 101 and the low (high gear ratio) oil chamber 102. , A cylinder hydraulic system for realizing the above-mentioned speed change.

First continuously variable transmission mechanism 18 and second continuously variable transmission mechanism
Twenty hydraulic servo devices are shown in simplified form in FIG. Roller support members 104 and 105 that rotatably support the power rollers 18c and 18d of the first continuously variable transmission mechanism 18 are supported rotatably about their axes and axially movable. The pistons 106 and 107 of the respective cylinders 100 are connected to the roller support members 104 and 105, respectively. The high side oil chamber touched above and below the pistons 106 and 107 (on the right and left sides in FIG. 5), respectively.
101 and the low side oil chamber 102 are defined. Here, on the power roller 18c side and the power roller 18d side, the relationship between the high side oil chamber and the low side oil chamber is opposite to each other, and the cylinder 100 on the power roller 18c side is on the upper side (right side in FIG. 5). The high-side oil chamber 101, the low-side oil chamber 102 on the lower side (the same left side), and the cylinder on the power roller 18d side, conversely, on the lower side (see FIG. 5).
A high-side oil chamber 101 is formed on the middle left side, and a low-side oil chamber 102 is formed on the upper side (the same right side). When changing the gear ratio by changing the contact position radius of the power rollers 18c and 18d with the input / output disc, the piston 106 and the piston 107 can move up and down in opposite directions by the hydraulic pressure acting on the oil chamber of each cylinder. , When the oil pressure in the low-side oil chamber 102 is relatively increased, the speed is changed to the deceleration side. Then, when the gear ratio approaches the target value, the oil pressure in the high-side oil chamber 101 rises, and the oil pressure difference between the low-side oil chamber 102 and the high-side oil chamber 101 decreases. As a result, the speed change speed becomes slower, and the speed change is completed.

The second continuously variable transmission mechanism 20 has basically the same structure, and the high side oil chamber 101 and the low side oil chamber 101 are provided on both sides of the pistons 116 and 117 connected to the roller supporting members 114 and 115, respectively. When the oil pressure in the low-side oil chamber 102 is relatively increased, the gear shifts to the deceleration side. After that, when the gear ratio approaches the target value, the hydraulic pressure in the high-side oil chamber 101 rises and the hydraulic pressure difference between the low-side oil chamber 102 and the high-side oil chamber 101 decreases. As a result, the speed change speed becomes slower and the speed change is completed.

FIG. 6 shows an example of the structure of the power roller support mechanism and the piston cylinder mechanism in the continuously variable transmission mechanism as described above. FIG. 6 shows a first continuously variable transmission mechanism.
Although one side portion (power roller 18d side portion) of 18 is shown, basically, the other one side portion (power roller 18c side portion) and each power roller side of the second continuously variable transmission 20 are basically the same. The structure can be substantially the same.

In this example, the feedback system for performing feedback control so that the actual gear ratio in the gear ratio control becomes the commanded target gear ratio is related to the roller support member 105 side in the first continuously variable transmission mechanism 18. 6 is also shown in FIG. The feedback system is
An extension shaft portion that rotates integrally with the rotation shaft portion of the roller support member 105 integrally with the piston 107 is pivotally supported by a shaft 123 and a precess cam 121 that is provided by being coupled to the lower end of the extension shaft portion at a portion that penetrates the valve body portion. Link 122, one arm of the link is brought into line contact (T) with the inclined surface (cam surface) 121a of the cam 121, and the other arm is adjusted with the adjusting screw 12
4 is brought into contact with the spool 73b serving as a feedback valve body of the forward speed change control valve 70 to change the actual speed ratio to the speed change control valve 70.
Feedback to 70 (The amount of feedback is the ratio L ₂
/ L ₁ ).

2 to 4, the elements of the control valve system other than the forward shift control valve 70, the reverse gear ratio command valve 80, the forward / reverse switching valve 81, and the regulator valve 82, which will be described later, will be briefly described. Putting them aside, they are: The manual valve 83 supplies the hydraulic pressure (line pressure) of the oil passage 150 generated as described later to the forward clutch 44 or the reverse brake 46 according to the position of the select lever to switch between forward and reverse. Also, lock-up control valve 84
Is a control valve for activating or deactivating the lockup, which is applied to the apply-side oil chamber 12e and the release-side oil chamber 12f of the torque converter according to the oil pressure obtained by the duty-controlled lockup solenoid 93 (FIG. 3).
Adjust the supply direction and the hydraulic pressure of the hydraulic pressure to control the engagement / release of the lockup clutch. Here, the lockup solenoid 93 is controlled by a control unit (not shown) together with the line pressure solenoid 94 (FIG. 3). The relief valve 512 is a valve that prevents the hydraulic pressure supplied to the torque converter from exceeding a certain value, thereby preventing the torque converter pressure from becoming excessive.

The constant pressure regulating valve 89 (FIG. 3) is a valve that regulates the hydraulic pressure (line pressure) of the oil passage 150 to a constant value by reducing it to a constant value, such as a lockup solenoid 93 and a line pressure solenoid 94. Regulates the constant pressure used by
Output to oil passages 170 and 171. The above-mentioned constant pressure is applied to each solenoid 93, 94, lockup control valve 84,
Supply the pressure modifier valve 90 (Fig. 3) to the oil passage
171 is connected to the port of the forward speed change control valve 70 described later.

The pressure modifier valve 90 adjusts the oil pressure in the oil passage 151 according to the operating state of the lockup solenoid 93, and uses this as a signal pressure (pressure modifier pressure) for adjusting the line pressure. It is supplied to the plug of and used for adjusting the line pressure. Here, the oil passage 151 is connected to the accumulator 91 (Fig. 3), the accumulator 91 absorbs the oil pressure change of the oil passage 151, and the accumulator 92 (Fig. 3) absorbs the oil pressure change of the oil passage 152. Prevents pulsation by preventing the line pressure from vibrating.

Accumulator control valve 86 (FIG. 2)
Is connected to the line pressure solenoid 94 through an oil passage 155, and adjusts the oil pressure in the oil passage 152 according to the operation of the line pressure solenoid. Since the oil pressure of the oil passage 152 acts on the plug of the regulator valve 82, the line pressure can be controlled by the line pressure solenoid 94, and the oil pressure of the oil passage 152 is the forward clutch accumulator.
87 and acts as back pressure for the reverse brake accumulator 88 (FIG. 2). These accumulators 87 and 88 are connected to the forward clutch 44 and the reverse brake 46, respectively,
The forward clutch accumulator 87 raises the hydraulic pressure of the forward clutch 44 and the reverse brake accumulator 88.
Is to reduce the rise in hydraulic pressure of the reverse brake 46.

The regulator valve 82 shown in FIG. 2 is a valve for adjusting the hydraulic pressure (line pressure) of the oil passage 150 to which the discharge pressure from the oil pump 95 is supplied, and is set to the right half position in the figure by a spring 82a. The spool 82b elastically supported and the plug 82c abutting on the upper end surface of the spool in the figure are provided. Basically, the oil pump 95 uses the spring 82 to discharge the oil discharged to the oil passage 150.
Although the pressure is adjusted to the pressure determined by the spring force of a, when the spool 82b applies a downward force in the drawing by the plug 82c, the pressure is increased by that amount to a required line pressure.

The regulator valve 82 includes a spool,
It has a port 82d that causes the pressure in the oil passage 150 to act on the spool pressure-receiving surface through an orifice and pushes it upward in the drawing, and ports 82e to 82h that are opened and closed according to the stroke position of the spool are provided. On the other hand, regarding the plug, in order to apply a force in the downward direction to the plug, the pressure modifier pressure from the pressure modifier valve 90 (FIG. 3) is passed through the oil passage 151, and the adjusted hydraulic pressure at the accumulator control valve 86 is changed. The oil is supplied through the oil passage 152, and is connected to the oil passage 153 for introducing the oil pump feedback pressure into the pilot chamber 82i on the plug end face as described later. Regarding the above ports 82e to 82h, the port 82e is connected to the oil passage 150, the port 82f is connected to the oil pump capacity control chamber 96 via the oil passage 154 having a bleed in the middle, and the port 82h.
Are connected to relief valves 85 via oil passages 155, respectively,
153 is provided by branching from the oil passage 154.

When the discharge pressure of the oil pump is supplied to the oil passage 150 in the state where the spool 82b is in the right half position in the drawing, the regulator valve 82 is increased in pressure by the spool 82b.
Is pushed upwards in the figure against the spring 82a, and the port 82
Connect e to port 80h. Basically, when the pressure in the oil passage 150 is set to a value corresponding to the spring force of the spring 82a in this way, the downward force in the figure due to the modifier pressure from the oil passage 151 acts on the plug 82c to cause the plug 82c to move. It abuts the spool 82b and its downward force acts on the spool 82b to assist the spring 82a. Therefore, the pressure adjusting point is set in a state corresponding to the modifier pressure acting as a signal pressure from the pressure modifier valve 90 to the regulator valve 82. When the force acting on the spool of the regulator valve becomes larger than the above-mentioned spring force as a force for pushing it downward in the figure and the pressure modifier pressure flowing from the oil passage 151 and becomes equal to or more than the pressure regulation value, the spool 82b Is pushed upward in the figure and port 82
The e and the port 82f are connected, and as a result, the feedback pressure from the regulator valve 82 acts on the oil pump 95, and the position of the cam ring is adjusted so that the eccentric amount is reduced. The oil pump 95 is a variable capacity vane pump, and the capacity becomes small when the amount of eccentricity is reduced, so the oil pump discharge pressure is reduced here. Thus, under the control of the cam ring, the oil pump discharge pressure is a pressure (line pressure) balanced with the force acting on the spool of the regulator valve 82.
Will be regulated. When the pressure modifier pressure is set to a pressure according to the engine load (engine output torque), the line pressure control can generate a line pressure according to the engine load.

Further, in the above, the oil pump feedback pressure is introduced into the pilot chamber 82i of the regulator valve 82 via the branch oil passage 153, and the engine speed, and accordingly the input of the first and second continuously variable transmission mechanisms 18 and 20. When the rotation speed is high, raise the pressure adjustment point of the oil pump discharge pressure. In this case, a downward force according to the pump control pressure is applied to the spool 82b of the regulator valve 82, and if the control is performed to back up from the rear end (upper end side in the figure) of the plug 82c, in the figure The above-mentioned spring is used to push downward.
In addition to the spring force of 82a and the pressure modifier pressure, the pressure flowing from the oil passage 153 acts, and the pressure adjustment point is set to a value higher than that in the case where the engine speed is low. That is, at high rotation speed, the oil pump control pressure rises to reduce the amount of eccentricity caused by the cam ring, and at the same time, the line pressure is raised to raise the pressure adjustment point to a predetermined amount higher (FIG. 7). .. FIG. 7 shows an example of characteristics of the transition of hydraulic pressure when the engine speed is used as a parameter.

In this example, the speed change control valve includes the regulator valve 82, the oil pump 95, and the oil pump capacity control chamber 96.
Means for correlating the oil pressure supplied to 70 with the input disk rotation speed is configured to change the shift control oil pressure supplied to the control valve in correlation with the increase in the engine rotation speed coupled to the input disk.

As described above, the line pressure generated in the oil passage 150 is supplied to the constant pressure regulating valve 89, the manual valve 83, the accumulator control valve 86, etc., and the forward shift control valve 70 and the reverse shift control are provided. Supply to the ratio command valve 80 (Fig. 4).

The forward speed change control valve 70 is a speed change control valve that is operated so as to have a commanded speed change ratio (target speed change ratio) when the forward / reverse speed changeover mechanism 36 is in the forward move state. The command valve 80 is a command valve for setting the constant speed ratio state when the forward-reverse switching mechanism 36 is in the reverse state.

The shift control valve 70 is a step motor that operates in response to an electric signal that commands a gear ratio.
71 is provided, the control valve 70 controls the high-side oil chamber 101 and the low-side oil chamber 101 of each cylinder 100 in the hydraulic servo devices of the first and second continuously variable transmission mechanisms 18 and 20 according to the operation of the step motor 71 during forward movement. The distribution of hydraulic pressure to the side oil 102 is adjusted to realize a predetermined gear ratio.

Therefore, the shift control valve 70 has a gear ratio command member 72 axially driven by the step motor 71 via the pinion 71a and the rack 72a, and is fitted into the sleeve 73a and the inner diameter portion of the sleeve. Spool 73b, a spring 73c for pushing the spool 73b downward in FIG. 4,
And a spring inserted between the sleeve 73a and the spool 73b.
73d. The spring 73d is used for the gear shift command member 72.
It is used to suppress the play at the joint between the sleeve 73a and the sleeve 73a.

Specifically, the gear ratio command member 72 and the sleeve 73a can be connected by a pin 73e. In this case, the pin 73e fixed to the gear ratio command member 72 is connected to the sleeve 73a. This is done by fitting a long slot in the side orthogonal direction. As a result, the gear ratio command member 72 and the sleeve 73a move integrally in the axial direction, but can move relative to each other in the rotational direction and the axis orthogonal direction. Therefore, the shift control valve 70 is driven by the rack and pinion mechanism as described above to form the rack 72a portion in the gear ratio command member axial direction, or with respect to the gear ratio command member side, Ports 72b to 72d are arranged to connect these ports to the oil passage 171 from the constant pressure regulating valve 89, the oil passage 172 leading to the lockup control valve 84, etc., and the oil passage 173 leading to the lockup solenoid 93. However, even when it is used also for lock-up control including a lock-up inhibitor, even if the total length of the gear ratio command member 72 and the sleeve 73a becomes long, an unreasonable force may act on both. It can be avoided and valve sticks etc. are less likely to occur.

On the sleeve and spool valve side, the shift control valve 70 is further provided with ports 73f to 73h. Port 73f
Connects this to the oil passage 150 and uses the line pressure of the oil passage as the hydraulic pressure to be supplied to the shift control valve 70, and uses this as the shift control pressure. Oil passages 174 and 175 are connected to the ports 73g and 73h, respectively, and these oil passages are connected to the high side oil chamber of each cylinder 100 through the forward / reverse switching valve 81 in the forward switching state. The oil passage 176 to 101 and the oil passage 175 are connected to the oil passage 177 to the low side oil chamber 102, respectively. The shift control valve 70 has a sleeve 73
Depending on the relative position of the spool 73b position with respect to a, the oil passage 17
To create a differential pressure at 4,175 (thus oil lines 176, 1
It operates through 77 to cause a hydraulic pressure difference between the two hydraulic chambers on both sides of the cylinder 100. In this case, the sleeve and spool valve portions are overlap valves. Regarding the point of the overlap valve,
I will touch on this later.

The spool 73b is pressed against the link 122 of the feedback mechanism of the hydraulic servo device by the spring 73c, and the other end of the link 122 is in contact with the slope 121a of the cam 121 which also constitutes the feedback mechanism. The feedback system has already been described in FIG. Here, the link 122 is the movement of the cam 12, and hence the movement of the roller support member 105 (up and down displacement,
According to the swinging behavior of the power roller), this is fed back to swing, but the spool 73b is stroked in the axial direction according to the swinging of the link. With respect to the sleeve 73a, the spool 73b is always in a predetermined axial position with respect to the sleeve 73a in a constant gear ratio state, supplies a hydraulic pressure of a predetermined pressure difference to the oil passages 174 and 175, and in a gear change state. The line pressure supplied from the oil passage 150 is distributed to the oil passages 174 and 175 as a shift control pressure according to the position, and the pressure difference between the oil passages is changed. In addition, in such shift control, the shift control valve 70 stabilizes the shift control during high-speed rotation of the input disc even when the sleeve and the spool valve part have a valve configuration with a small amount of oil leakage. In order to realize this, a gear shift control pressure that depends on the input rotation speed is supplied, and feedback control is performed at a high rotation speed with a supply oil pressure that is greater than that at a low speed rotation.

The reverse gear ratio command valve 80 has a spool 80b which is biased upward in the drawing by a spring 80a, and a link 75 and a cam 76 are provided in association therewith, and ports 80c-80e are provided. Prepare Port 80c connects it to line pressure oil line 150 and ports 80d and 80e respectively to oil line 179,
The oil passages 179 and 180 are connected to the forward / reverse switching valve 81. When the vehicle is in reverse, the reverse gear ratio command valve 80
The second continuously variable transmission mechanism 18, 20 is in a constant gear ratio state,
Unlike the case of the shift control valve 70 described above, the step motor for reverse drive is not used. The reverse cam 76 can be provided on the roller support member of the hydraulic servo device, and the feedback link 75 of the cam 76 is a link 12 for feeding back the rotation of the cam 121 to the forward shift control valve 70.
The same as 2 can be used.

The forward / reverse switching valve 81 is used to switch the supply of operating hydraulic pressure to the hydraulic servo device during forward and reverse travel. The forward / reverse switching valve 81 includes a spool 81b biased downward in the figure by a spring 81a, and by switching the spool between a left half position and a right half position in the figure by a forward / backward movement detection member 77,
It is used to reverse the operating state of the hydraulic servo system during forward movement and during reverse movement. The forward / backward movement detection member 77 rotates while discriminating between forward movement and backward movement, and has a position rotated counterclockwise in the drawing (forward movement position) and a position rotated clockwise (reverse movement position). And 2 positions. Forward / reverse selector valve 81 port 81c
~ 81h are the oil passages 176, 174, 175, 1 as shown, respectively.
Connect with 79, 180.

Oil passage from the reverse gear ratio command valve 80 described above
Regarding the hydraulic pressure by the valves 179 and 180, the forward / reverse switching valve 81 communicates with the oil passages 175 and 174 in the reverse speed switching state of the spool 81b in the right half position in the figure to establish a constant gear ratio state.
When the forward clutch 44 of the forward / reverse switching mechanism 36 is released and the reverse brake 46 is engaged, the forward / reverse detecting member 77 is at the clockwise rotating position in the figure and the spool 81b of the forward / reverse switching valve 81 is in the clockwise position.
Is in the state shown in the right half position in the figure. In such a state,
The hydraulic pressure supplied from the reverse gear ratio command valve 80 acts on the oil passages 174 and 175, so that the reverse gear ratio command valve 80 maintains the oil passages 179 and 180, and thus the servos, so that the reverse gear ratio command valve 80 is in a preset constant gear ratio state. It controls the hydraulic pressure of each corresponding oil passage leading to the device.

In the forward state in which the forward clutch 44 of the forward / reverse switching mechanism 36 is engaged, the forward / backward detecting member 77 is rotated counterclockwise in the figure, and the spool 81 of the forward / reverse switching valve 81 is rotated.
a is in the state shown in the left half position in the figure. In this state, the oil passages 174 and 175 from the forward speed change control valve 70 are connected to the oil passages 176 and 175.
The hydraulic pressure in the high-side oil chamber 101 and the low-side oil chamber 102 of the cylinder 100 of the hydraulic cylinder device is controlled by the shift control valve 70. In the figure, the state of the left half position of the shift control valve 70 shows the high (small gear ratio) side state, and the state of the right half position shows the low (high gear ratio) side. When the step motor 71 is operated to move the shift command member 72 to a predetermined position, the sleeve 73a moves accordingly.

At this time, since the spool 73b does not move immediately, the relative relationship between the spool 73b and the sleeve 73a changes, and the differential pressure between the oil passage 174 and the oil passage 175, that is, the high side oil chamber and the low side oil chamber. The differential pressures of the oil passages 176 and 177 communicating with each other change, and the piston 106 and the piston 10 of the first continuously variable transmission mechanism 18 are changed.
7 are moved in the opposite directions, and similarly, on the second continuously variable transmission 20 side, the pistons 116, 117 are also moved in the opposite directions according to the direction of the differential pressure. When the piston of each cylinder 100 moves, the direction of the tangential force acting on the power rollers 18c, 18d and 20c, 20d changes accordingly, so that each roller support member 104, 105 and 114, 115 has its own rotary shaft. The center of rotation of the power roller 18c, 18d, the input disk 18d and the output disk 18b contact position radius, the power roller 20c, 20d input disk 20a and the output disk
The contact position radii of 20b change, respectively, so that such a swinging motion of the power roller causes a speed change.

As for shifting, as described above, the shift control pressure (line pressure of the oil passage 150) is distributed by the movement of the sleeve 72a integrated with the gear shift command member 72 to change the pressure difference between the oil passages 174 and 175, and the piston Center of rotation of the power roller (Fig. 6
In this case, the axis O ₁ ) is shifted (offset) from the center of rotation of the input / output disk (axis O _{3 in} FIG. 6). In this case, both the swinging movement and the vertical movement are fed back to the shift control valve 70. To be done. The vertical displacement of the roller supporting member 105 on the power roller 18d side integrated with the cam 121 and the rotation around the axis O ₂ (FIG. 6) are fed back to the spool 73b via the cam 121 and the link 122, and the spool 73b is , Follows the displacement of the sleeve 72a according to the shift command of the shift command member 72, and returns to the original relative position with respect to this. As a result, the differential pressure between the oil passage 174 and the oil passage 175 becomes stable in a state where the designated gear ratio is maintained. Thus, the speed change control valve 70 basically performs feedback control so that the actual speed change ratio becomes the target speed change ratio, and when the power roller is in the tilted state corresponding to the speed change command, the offset is set to 0 and designated. The gear ratio can be maintained.

The shift control valve 70 also has a function of damping the swinging behavior of the power roller during the shift. The damping function applies a hydraulic pressure in the opposite direction to the previous stroke with the stroke of the spool 73b when the power roller goes beyond the state required to achieve the specified gear ratio when shifting, and returns the overshoot by the reverse feedback action. However, in the present control device, it is possible to increase the sensitivity of the spool valve portion when the input disc rotates at a high speed and to enhance the damping effect.

The line pressure of the oil passage 150, which is supplied to the shift control valve 70 as the shift control pressure, increases as the engine speed by the regulator valve 82 increases, as shown in the characteristic of FIG. ,To rise. Thus, as the shift control pressure increases, the rate of pressure change with respect to the phase shift of the shift control valve 70 increases in the above-described vibration damping operation. Here, since the damping is performed by the hydraulic pressure generated by the stroke of the spool 72b of the shift control valve 70, the ratio of the pressure change to the stroke amount of the spool 72b, that is, the sensitivity of the so-called spool valve is set at a high rotation speed. Can be raised. Therefore, in the speed change control, when the input rotation speed is high and the power roller swings more quickly than in the low speed rotation to perform the speed change, the damping function of the speed change control valve 70 is increased accordingly. Therefore, it is possible to stabilize the shift control when the rotation speed is high.

Further, according to the above configuration, even if the overlap valve is used as the shift control valve to be used, that is, the valve having a small leak amount is used, the shift control at the time of high speed rotation can be stabilized. To increase the spool valve sensitivity of the shift control valve,
A method of using the just change valve as the shift control valve is also conceivable, but in this case, since there is no overlap amount, oil leakage occurs even in the steady state, and loss of pump oil pressure is large, which causes deterioration of fuel consumption. On the other hand, in this device, the overlap valve can be used instead of the just-lap valve. Therefore, the present device capable of increasing the shift control pressure by increasing the input rotation speed and changing the sensitivity of the shift control valve 70 depending on the input rotation speed has a smaller leak amount as compared with the case of using the jar strap valve. In addition, when a damping function is more required at the time of high-speed rotation, this can be appropriately met, and the control can be stabilized.

[0048]

According to the present invention, the hydraulic pressure supplied to the speed change control valve for operating the hydraulic actuator for the power roller of the toroidal speed change mechanism depends on the rotational speed of the input disk, and the hydraulic pressure is increased at high speed. It is possible,
To stabilize the shift control during high speed rotation by increasing the sensitivity of the shift control valve during high speed rotation and increasing the damping function of the behavior of the power roller by the shift control valve when performing feedback control. It is possible to realize the above by using a control valve that can achieve the above and has a small leak amount.

[Brief description of drawings]

FIG. 1 is a skeleton diagram showing an example of a basic configuration of a toroidal continuously variable transmission equipped with a shift control device according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a shift control hydraulic circuit according to an embodiment of the present invention, with a part thereof being divided.

FIG. 3 is a circuit diagram showing another part of the same.

FIG. 4 is a circuit diagram showing a portion including a shift control valve, showing still another portion.

FIG. 5 is a circuit diagram showing another part of the hydraulic servo device of the toroidal continuously variable transmission mechanism in a simplified manner.

FIG. 6 is a sectional view showing an example of a specific structure of a hydraulic servo device.

FIG. 7 is a diagram showing an example of shift control pressure characteristics by the embodiment apparatus.

[Explanation of symbols]

 10 Toroidal continuously variable transmission 18, 20 Continuously variable transmission mechanism (toroidal transmission mechanism) 18a, 20a Input disc 18b, 20b Output disc 18c, 18d, 20c, 20d Power roller 70 Forward transmission control valve 82 Regulator valve 82i Pilot chamber 95 Oil pump 100 Cylinder 101, 102 Oil chamber 121 Cam 122 Link 150, 153 Oil passage

Claims (1)

[Claims] 1. A toroidal continuously variable transmission having an input / output disk and a power roller between both disks, wherein the power roller is actuated by an actuator to effect a speed change. A shift control device for a toroidal continuously variable transmission, characterized in that the hydraulic pressure supplied is controlled to be large when the rotation of an input disk is high, depending on the input rotation speed.