JPH0754982A - Hydraulic circuit for automatic transmission - Google Patents

Abstract

PURPOSE:To provide a hydraulic circuit for automatic transmission which can keep constant the working oil pressure given by a decompression valve irrespective of changing temp. of the working oil. CONSTITUTION:A decompression valve consists of a solenoid reducing valve 88 to decompress the pressure of a working oil discharged from an oil pump 13 to a certain preset value, a feedback circuit 169 to make feedback control of the working oil pressure to be fed from the decompression valve to a throttle modulator valve 91, etc., and a pressure adjusting means 171 which adjusts the working oil pressure to the set value by varying the quantity of working oil leaking at the circuit 169 in accordance with the oil temp.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic circuit for an automatic transmission having a pressure reducing valve for reducing the working hydraulic pressure in the hydraulic circuit to a preset pressure.

[0002]

2. Description of the Related Art Generally, an automatic transmission mounted on a vehicle is
For example, as disclosed in JP-A-62-35149, a regulator valve for adjusting the line pressure in a hydraulic circuit, a control valve (modifier valve) for controlling the pilot pressure of the regulator valve, and a control valve It has a hydraulic circuit provided with a pressure reducing valve for generating an original pressure, and is configured to generate a line pressure according to an operating state of an automobile by each of the valves.

The pressure reducing valve normally has a spool installed in the valve body, a spring for urging the spool toward one end of the valve, and a feedback circuit provided at the one end of the valve. The feedback hydraulic circuit is configured to adjust the hydraulic pressure output to the control valve to a constant value corresponding to the biasing force of the spring.

[0004]

SUMMARY OF THE INVENTION As described above, in the pressure reducing valve configured to adjust the operating oil pressure output from the pressure reducing valve to a constant value according to the urging force of the spring,
There is a problem in that it is difficult to maintain the working oil pressure at a constant value because the working oil pressure varies due to changes in the viscosity of the working oil and changes in the biasing force of the spring that occur corresponding to the temperature of the working oil. .

For example, when the temperature of the hydraulic oil is high, the viscosity of the hydraulic oil is low, the amount of hydraulic oil led out from the drain port of the pressure reducing valve is increased, and the Young's modulus of the spring is decreased, which causes Since the force is reduced, the amount of hydraulic oil output from the pressure reducing valve is reduced as compared with the normal time, and the pressure of the hydraulic oil input to the duty control section of the control valve is reduced.

Therefore, in order to prevent the pilot pressure supplied from the control valve to the pilot port of the regulator valve from dropping below a predetermined value when the oil temperature is high, the pilot pressure should be set higher than an appropriate value. It is necessary to set the operating oil pressure, but in the case of such a configuration, the pilot pressure becomes higher than necessary during normal operation, and thereby the line pressure regulated by the regulator valve becomes higher than an appropriate value. There is a problem.

That is, as shown by the solid line A in FIG. 12, when the oil temperature is high, the operating oil pressure is adjusted so that the duty pressure input to the control valve and the line pressure output from the regulator valve have an appropriate relationship. When set, the line pressure output from the regulator valve normally becomes high as shown by the broken line B in FIG. 12, the shift control becomes unstable, and the driving force of the oil pump is wasted. There is a problem that fuel efficiency deteriorates and durability of each part deteriorates.

The present invention has been made in order to solve the above-mentioned problems, and provides an automatic transmission capable of maintaining the working oil pressure output from the pressure reducing valve at a constant value regardless of the temperature change of the working oil. The purpose is to provide a hydraulic circuit.

[0009]

The invention according to claim 1 is
A pressure reducing valve that reduces the pressure of the hydraulic oil discharged from the oil pump to a preset constant value, a feedback circuit that feedback-controls the hydraulic pressure output from this pressure reducing valve, and the amount of hydraulic oil that leaks from this feedback circuit Pressure adjusting means is provided for adjusting the operating oil pressure to a constant value by changing it according to the temperature.

According to the second aspect of the present invention, a regulator valve that regulates the line pressure of a hydraulic circuit, a control valve that controls the pilot pressure of the regulator valve, a decompression valve that creates the original pressure of the control valve, and the decompression valve are provided. A feedback circuit for feedback-controlling the hydraulic oil pressure output from the valve, and a pressure adjusting means for adjusting the hydraulic oil pressure to a constant value by changing the amount of hydraulic oil leaking from the feedback circuit in accordance with the oil temperature. It is provided.

[0011]

According to the first aspect of the present invention, when the oil temperature in the hydraulic circuit rises, the amount of hydraulic oil leaking from the feedback circuit of the pressure reducing valve to the outside increases. As a result, the amount of hydraulic oil output from the pressure reducing valve is prevented from decreasing, and the hydraulic pressure output from the pressure reducing valve is always maintained at a constant value.

According to the second aspect of the present invention, the operating oil pressure output from the pressure reducing valve to the control valve is maintained at a constant value by the pressure adjusting means regardless of the oil temperature. By appropriately controlling the pilot pressure of the valve, the regulator valve controls the line pressure of the hydraulic circuit to an appropriate value according to the operating state of the vehicle.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 schematically shows an example of a mechanical structure of an automatic transmission to which the present invention is applied. The automatic transmission 10 includes a torque converter 20, a multi-stage transmission gear mechanism 30 connected to the output side thereof, and the transmission gear mechanism 3
A plurality of friction elements 41 to 46 such as clutches and brakes for switching the power transmission path of 0 and the one-way clutch 5
1 and 52.

The torque converter 20 includes a case 21 connected to the output shaft 1 of the engine, a pump 22 fixed in the case 22, and a pump 22 arranged so as to face the pump 22 through hydraulic oil. Driven turbine 2
3 and a stator 25 provided between the pump 22 and the turbine 23 and supported by the transmission case 11 via the one-way clutch 24 to increase the torque. Turbine shaft 27
It is adapted to be transmitted to the speed change gear mechanism 30 via.

The torque converter 20 is provided with a lockup clutch 26 which directly connects the input side and the output side of the torque converter 20. A pump shaft 12 penetrating the turbine shaft 27 is connected to the output shaft 1 of the engine, and the pump shaft 12 drives an oil pump 13 mounted at the rear end of the automatic transmission. Has become.

The speed change gear mechanism 30 is composed of a Ravigneaux type planetary gear device arranged on the turbine shaft 27. This planetary gear device includes a small-diameter sun gear 31 loosely fitted in a turbine shaft 27, and a turbine shaft 2 which is located behind the small-diameter sun gear 31.
A large-diameter sun gear 32 loosely fitted in 7, a plurality of short pinion gears 33 meshing with the small-diameter sun gear 31;
A long pinion gear 34 whose front half engages with the short pinion gear 33 and whose rear half engages with the large-diameter sun gear 32, a carrier 35 which rotatably supports the short pinion gear 33 and the long pinion gear 34, and an engagement with the long pinion gear 34. And a ring gear 36. The output gear 14 is connected to the ring gear 36.

A forward clutch 41 and a first one-way clutch 51 are provided in series between the turbine shaft 27 and the small-diameter sun gear 31, and a coast clutch 42 is provided in parallel with these clutches 41, 51. ing. Further, a 3-4 clutch 43 is provided between the turbine shaft 27 and the carrier 35, and
A reverse clutch 44 is provided between the turbine shaft 27 and the large-diameter sun gear 32.

Between the large-diameter sun gear 32 and the reverse clutch 44, a 2-4 brake 45 which is a band brake for fixing the large-diameter sun gear 32 is provided.
Further, a second one-way clutch 52 that receives a reaction force of the carrier 35 and a low reverse brake 46 that fixes the carrier 35 are provided in parallel between the carrier 35 and the transmission case 11.

The speed change gear mechanism 30 itself has four forward speeds and one reverse speed, and the clutches 41 to 44 and the brakes are operated based on the selection operation for selecting the range and the control according to the operating state. By operating 45 and 46 appropriately, the 1st to 4th speed in the D range, the 1st to 3rd speed in the S range, the 1st to 2nd speed in the L range, and the reverse speed in the R range are obtained. Has been done.

The relationship between the operating states of the clutches 41 to 44, the brakes 45 and 46, and the one-way clutches 51 and 52 and the shift speed will be described. First, in the first speed, while the forward clutch 41 is engaged,
The first and second one-way clutches 51 and 52 are locked, and the output rotation of the torque converter 20 is transmitted from the turbine shaft 27 to the forward clutch 41 and the first clutch.
The small-diameter sun gear 31 through the one-way clutch 51.
Entered in. Then, with the carrier 35 fixed by the action of the second one-way clutch 52, the rotation is transmitted from the small-diameter sun gear 31 to the ring gear 36 via the short pinion gear 33 and the long pinion gear 34. As a result, the small-diameter sun gear 31 and the ring gear 3 are
Thus, the first speed state with a large reduction gear ratio corresponding to the diameter ratio of 6 is obtained.

Next, in the second speed, in addition to the above-described first speed state, the 2-4 brake 45 is engaged, the large-diameter sun gear 32 is fixed, and the second one-way clutch 52 becomes idle. Therefore, the rotation transmitted from the turbine shaft 27 to the small diameter sun gear 31 is transmitted to the long pinion gear 34 via the short pinion gear 33, and the long pinion gear 34 revolves on the large diameter sun gear 32. 35
Rotates. As a result, the carrier 35
The rotation speed of the ring gear 36 is increased by the rotation speed of 1 to obtain the 2nd speed state in which the reduction ratio is smaller than that in the 1st speed.

In the 3rd speed, from the above 2nd speed state, 2-
At the same time that the 4 brake 45 is released, the 3-4 clutch 43 is engaged. Therefore, the rotation of the turbine shaft 27 is input to the small-diameter sun gear 31 via the forward clutch 41 and the first one-way clutch 51, and is also input to the carrier 35 via the 3-4 clutch 43. As a result, the entire transmission gear mechanism 30 rotates integrally, and the third speed state in which the ring gear 36 rotates at the same speed as the turbine shaft 27 is obtained.

In the 4th speed, the 2-4 brake 45, which was once released in the 3rd speed, is reengaged.
Therefore, the rotation of the turbine shaft 27 is input to the carrier 35 from the 3-4 clutch 43, and the long pinion gear 34 is revolved. The large-diameter sun gear 32 meshed with the long pinion gear 34 causes the rotation of the 2-4.
Since it is fixed by the brake 45, the long pinion gear 34 revolves around the carrier 35 while revolving. As a result, the ring gear 36 meshing with the long pinion gear 34 is rotationally driven by being accelerated by the rotation of the carrier 35 by the amount of rotation of the long pinion gear 34, whereby the fourth speed state of the overdrive state is obtained.

Further, at the reverse speed, the reverse clutch 44 and the low reverse brake 46 are engaged, the rotation of the turbine shaft 27 is input to the large-diameter sun gear 32, and the carrier 35 is transferred to the body case 11.
Fixed to. Therefore, the rotation is transmitted from the large-diameter sun gear 32 via the long pinion gear 34 to the ring gear 36 via a fixed gear train, and the large-diameter sun gear 3
2 and the ring gear 36, the reduction ratio corresponding to the ratio of the diameters of the ring gear 36 and the ring gear 36 is obtained.
And rotate in the opposite direction.

Since the first one-way clutch 51 that transmits rotation at the 1st to 3rd speeds and the second one-way clutch 52 that receives a reaction force at the 1st speed idles during coasting, the engine brake operates at these gears. I will not do it, but the third speed in the D range and a few in the S range
In the 1st and 2nd speeds of the L speed and L range, the coast clutch 42 in parallel with the first one-way clutch 51 is engaged, and
At the first speed in the range, the low reverse brake 46 in parallel with the second one-way clutch 52 is engaged, so that engine braking can be obtained at these shift speeds.

The relationship between the operation of each of the friction elements 41 to 46 and the one-way clutches 51, 52 and the shift speed is summarized in Table 1 below.

[0027]

[Table 1]

Main parts of the hydraulic circuit 60 for supplying and discharging hydraulic oil to and from the actuators of the friction elements 41 to 46 will be described with reference to FIG. Here, among the above-mentioned actuators, the hydraulic actuator 45a of the 2-4 brake 45 includes an apply port 45b and a release port 45.
c and the hydraulic pressure is supplied only to the apply port 45b, the 2-4 brake 45 is engaged, and the hydraulic pressure is not supplied to both ports 45b and 45c. Port 45b, 4
It is configured to release the 2-4 brake 45 when the hydraulic pressure is supplied to both 5c. Further, the actuators of the other friction elements 41 to 44, 46 are composed of ordinary hydraulic pistons, and fasten the friction elements when hydraulic oil is supplied.

The hydraulic circuit 60 has, as its main components, a regulator valve 61 for adjusting the pressure of the hydraulic oil discharged from the oil pump 13 to the main line 110 to a predetermined line pressure, and a range selection by manual operation. There are provided a manual valve 62 to be operated and first to third shift valves 63 to 65 which operate according to the shift speed to supply and discharge the hydraulic oil to and from the friction elements 41 to 46. The manual valve 62 can set the forward range of D, S, L, the R range, and the P range. In the forward range, the main line 110 is set to the forward line 111, and in the R range, The reverse lines 112 are connected to each other.

The first to third shift valves 63 to
65 has control ports 63a, 64a,
65a is provided. The first and second control valves 63a and 64a of the first and second shift valves 63 and 64 are branched from the forward line 111, respectively.
The control pressure lines 113 and 114 are connected. Also,
The control port 65a of the third shift valve 65 has a third control line 115 branched from the main line 110.
Connected to the control pressure line 11
3, 114 and 115 respectively have first to third gears for shifting.
Solenoid valves 66 to 68 are provided.

Of the solenoid valves 66 to 68, the first and second solenoid valves 66 and 67 are respectively O-shaped.
When in the N state, the control pressure of the corresponding control ports 63a and 64a is discharged to position the spools of the first shift valve 63 and the second shift valve 64 on the left side in the drawing, and when in the OFF state, the above control ports Control pressures are introduced into the 63a and 64a from the first and second control pressure lines 113 and 114 to position the spools on the right side against the biasing force of the springs. In addition, the third solenoid valve 68 discharges the control pressure of the control port 65a corresponding to the third solenoid valve 68 when it is turned on to release the control pressure from the third shift valve 65.
The spool is located on the right side in the drawing, and when it is off, a control pressure is introduced from the third control line 115 to the control port 65a to position the spool on the left side.

The solenoid valves 66 to 68 are ON / OFF controlled by a signal from a controller, which will be described later, based on a map preset according to the traveling speed of the automobile and the throttle opening of the engine. Accordingly, the positions of the spools of the shift valves 63 to 65 are displaced and the oil passages communicating with the friction elements 41 to 46 are switched.
The gears are fastened in a combination as shown in FIG. 5, and the gears are switched according to the operating state. In this case, the relationship between each shift speed in the D, S, and L forward ranges and the ON / OFF combination pattern of the first to third solenoid valves 66 to 68 is set as shown in Table 2 below. ing.

[0033]

[Table 2]

On the other hand, when the spool of the manual valve 62 is set to the forward range of D, S, and L, the line 116 is branched from the forward line 111 communicated with the main line 110, and the line 116 is a forward clutch. It becomes a line and is guided to the forward clutch 41 via the orifice 69 and the one-way orifice 70. Therefore, the forward clutch 41 is always engaged in the D, S, and L ranges. In addition,
The forward clutch line 116 is connected to the downstream side of the one-way orifice 70 via a line 117.
The -D accumulator 71 is connected.

The forward line 111 is guided to the first shift valve 63, and the first solenoid valve 66 is turned on.
When in the N state and the spool of the first shift valve 63 is located on the left side, it communicates with the servo apply line 118 and reaches the apply port 45b of the servo piston 45a via the orifice 72. Therefore, the above D, S,
When the first solenoid valve 66 is ON in the L range, that is, the 2nd to 4th speeds in the D range, the 2nd and 3rd speeds in the S range, and the 2nd speed in the L range, servo apply pressure is introduced to the apply port 45b. The 2-4 brake 45 is engaged when the servo release pressure is not introduced to the release port 45c. A 1-2 accumulator 74 is connected to the apply port 45b via a line 119 and an accumulator valve 73.

The forward line 111 is also guided to the third shift valve 65, the third solenoid valve 68 is turned off, and the spool of the third shift valve 65 is located on the left side, It communicates with the coast clutch line 120. This coast clutch line 120
Reaches the coast clutch 42 via the coast reducing valve 75 and the one-way orifice 76. Therefore, when the third solenoid valve 68 is OFF in the D, S, L ranges, that is, the coast clutch 42 is engaged in the D, S range third speed, the S, L range second speed, and the L range first speed. It

Further, the forward line 111 is also guided to the second shift valve 64, and the second solenoid valve 67 is turned off.
In the F state, when the spool of the second shift valve 64 is located on the right side, the 3-4 clutch line 121 is brought into conduction.
The 3-4 clutch line 121 reaches the 3-4 clutch 43 via the 3-4 control valve 77. Therefore, when the second solenoid valve 67 is OFF in the D, S, L ranges, that is, in the D range 3, 4
The 3-4 clutch 43 is engaged at the third speed of the third speed and the S range.

The line 122 branched from the 3-4 clutch line 121 is guided to the third shift valve 65,
When the third solenoid valve 68 is off and the spool of the third shift valve 65 is located on the left side, the servo release line 1 communicating with the servo release port 45c communicating with the release port 45c of the servo piston 45a.
Connect to 23. Therefore, when both the second and third solenoid valves 67 and 68 are in the OFF state in the D, S, and L ranges, that is, the third speed in the D range and the third speed in the S range.
At high speed, the servo release pressure is introduced into the release port 45c of the servo piston 45a, and the 2-4 brake 45 is released.

A line 124 is branched from the forward line 111, and this line 124 is also led to the first shift valve 63. The line 124 communicates with the second shift valve 64 when the spool of the first shift valve 63 is located on the right side when the first solenoid valve 66 is in the OFF state. On the other hand, a line 126 communicating with the line 125 is connected to the second shift valve 64 when the second solenoid valve 67 is in the ON state and the spool of the second shift valve 64 is located on the right side. Is led to the third shift valve 65 via the shuttle ball valve 78 and the line 127.

The line 127 is a low reverse brake line 128 via a low reducing valve 79 when the third solenoid valve 68 is OFF and the spool of the third shift valve 65 is located on the left side.
Communicate with. Therefore, when the first, second, and third solenoid valves 66, 67, 68 are in OFF, ON, OFF states in the D, S, L ranges, respectively, that is, the low reverse brake 46 is engaged at the first speed in the L range. .

Further, the retreat line 112 communicating with the main line 110 in the R range is a third line through the line 129 branched from the retreat line 112, the orifice 80, the one-way orifice 81, the shuttle ball valve 78 and the line 127. When the spool of the third shift valve 65 is located on the left side while being guided to the shift valve 65 and the third solenoid valve 68 is in the OFF state, the third reverse valve 65 communicates with the low reverse brake line 128.

The reverse line 112 serves as a reverse clutch line 130, and a reverse clutch 4 is provided via a one-way valve 82 that opens in the hydraulic oil supply direction.
It has reached 4. Therefore, in the R range, when the third solenoid valve 68 is in the OFF state, the low reverse brake 46 is engaged and the reverse clutch 44 is always engaged. The line 131 branched from the line 129 between the one-way orifice 81 and the shuttle ball valve 78 has an N-
The R accumulator 83 is connected.

Further, the hydraulic circuit 60 is provided with a fourth shift valve 84 for controlling the lockup clutch 26 in the torque converter 20 and a lockup control valve 85. The converter line 132 led from the regulator valve 61 via the converter relief valve 86 is connected to the fourth shift valve 84 and the lockup control valve 85, and is provided to the fourth shift valve 84. A control pressure line 134 communicating with the main line 110 via a line 133 is connected to the control port 84a.

The control pressure line 134 is provided with a fourth solenoid valve 87 for lockup.
Since the spool of the fourth shift valve 84 is located on the left side when the solenoid valve 87 is OFF, the converter line 132 communicates with the release line 135 that communicates with the lockup release chamber 26a in the torque converter 20, thereby locking. The up clutch 26 is released to enter the converter state.

By turning on the fourth solenoid valve 87 and discharging the control pressure from the control port 84a of the fourth shift valve 84, the spool of the fourth shift valve 84 moves to the right side in the drawing. Then, the converter line 132 communicates with the engagement line 136 that communicates with the lock-up engagement chamber 26b in the torque converter 20, whereby the lock-up clutch 26 is engaged.

At this time, the release line 135 communicates with the lockup control valve 85 via the fourth shift valve 84 and the intermediate line 137, and the operating pressure adjusted by the lockup control valve 85 is used as the lockup release pressure. Lockup clutch 26
Is supplied to the lock-up release chamber 26a. That is, the control pressure line 1 led from the main line 110 via the solenoid reducing valve 88 is connected to the control port 85a at one end of the lockup control valve 85.
38 is connected, and pressure regulation prevention port 8 on the other end side
5b is a pressure regulation prevention line 1 leading to the forward line 111.
39 is connected.

A first duty solenoid valve 90 is installed downstream of the orifice 89 provided in the control pressure line 138, and the lockup is performed according to the duty ratio given to the first duty solenoid valve 90. Control port 8 of control valve 85
By adjusting the control pressure supplied to 5a, the converter line 132 and the fastening line 136 are provided on condition that the line pressure is not supplied to the pressure regulation blocking port 85b on the other end side via the pressure regulation blocking line 139. The pressure difference between the engagement pressure supplied to the lock-up engagement chamber 26a via the intermediate line 137 and the release pressure supplied to the lock-up chamber 26b via the release line 135 is adjusted, and the lock-up clutch 26 is completely engaged. The state or a predetermined slip state is controlled.

On the other hand, the lockup control valve 8
5 to the pressure regulation prevention port 85b
When the line pressure is supplied through the control valve 85, the spool of the control valve 85 is fixed in the left side position. Therefore, the operating pressure of the lockup release chamber 26a in the lockup clutch 26 is controlled by the release line 135, the fourth shift valve 84, and the intermediate line 137.
Is discharged from the drain port of the lock-up control valve 85a through the lock-up control valve 85a, and the lock-up clutch 26 is completely engaged in the lock-up state.
The drain port is provided with an orifice having a predetermined diameter, so that the hydraulic oil supplied to the engagement chamber 26b of the lockup clutch 26 through the engagement line 136 flows into the release chamber 26a in the communicating state. Is configured so that it is not excessively discharged.

First duty solenoid valve 90
The operating characteristic of is set such that the duty control pressure decreases as the duty ratio D increases. That is, when the duty ratio D is 100%, the drain port is always opened, and the pressure level of the control pressure line 132 on the downstream side of the orifice 89 becomes 0, whereas the duty ratio D becomes 0. At times, the drain port is always shut off to maintain the pressure level at the maximum pressure.

Further, in the hydraulic circuit 60, a throttle modulator valve 91 (control valve) for controlling the line pressure regulated by the regulator valve 61, and a second duty solenoid valve 92 for operating this valve. And are provided. The throttle modulator valve 91 is connected to the main line 1 via the solenoid reducing valve (pressure reducing valve) 88.
A line 140 leading to 10 is introduced, and a duty control pressure adjusted by a second duty solenoid valve 92 that periodically opens and closes is introduced into a control port on one end side. The throttle modulator valve 91 is configured to generate the throttle modulator pressure according to the duty ratio D of the second solenoid valve 92.

The solenoid reducing valve 88
As shown in FIG. 3, has a spool 166 slidably installed on the valve body, and a spring 167 that biases the spool 166 toward the one end portion 88a side. In addition, the solenoid reducing valve 8
8, a duty control line 168 communicating with the control port 91a of the throttle modulator valve 91 is connected, and part of the hydraulic oil output to the duty control line 168 is connected to one end 88a of the spool 166.
A feedback circuit 169 for returning to the side is provided.

From the oil pump 13 to the main line 1
A part of the hydraulic oil supplied to the duty control line 168 via the solenoid valve 10 and the solenoid reducing valve 88 is returned from the feedback circuit 169 to the one end 88a side of the spool 166. Further, the solenoid reducing valve 88 includes a spool 166.
In accordance with the balance between the urging force of the hydraulic oil supplied to the one end portion 88a side and the urging force of the spring 167, it is output from the duty control line 168 to the control port 91a of the throttle modulator valve 91 as a source pressure. It is configured to adjust the amount of hydraulic oil that is discharged and the amount of hydraulic oil that is discharged from the drain port 170.

In the feedback circuit 169, the pressure of the hydraulic oil output from the solenoid reducing valve 88 is increased by increasing or decreasing the amount of hydraulic oil leaking from the feedback circuit 169 in proportion to the temperature of the hydraulic oil. Pressure adjusting means 1 for adjusting to a constant value
71 is provided. As shown in FIG. 4, the pressure adjusting means 171 includes an opening 172 of a passage communicating with the feedback circuit 169, a closing plate 173 closing the opening 172, and a bimetal 174 supporting the closing plate 173. have.

The state of the bimetal 174 changes according to the temperature of the hydraulic oil, and is normally in a linear state as shown in FIG. 5, and the closing plate 173 covers substantially the entire opening 172. ing. And
When the oil temperature rises, as shown in FIG.
4 is curved, the closing plate 173 is displaced laterally, the opening area of the opening 172 is increased accordingly, and the amount of hydraulic oil leaking from the opening 172 is increased. .

As described above, when the amount of hydraulic oil led out from the footback circuit 169 increases as the oil temperature rises, one end 88a of the solenoid reducing valve 88 is fed via the feedback circuit 169.
The amount of hydraulic oil returned to the side decreases. As a result, the Young's modulus of the spring 167 decreases as the oil temperature rises, and so on.
Is prevented from being hindered, and the operating oil pressure output to the throttle modulator valve 91 via the duty control line 168 is automatically controlled so as to be maintained at a constant value. Become.

The operating oil pressure output from the solenoid reducing valve 88 via the duty control line 168 is controlled by the second solenoid valve 92 provided on the duty control line 168 to control the supply amount thereof. A duty control pressure is supplied to the control port 91a of the throttle modulator valve 91.

The duty ratio D of the second solenoid valve 92 is set in accordance with, for example, the throttle opening degree of the engine, and the throttle modulator pressure corresponding to this is set as shown in FIG. , The first pressure increasing port 61a of the regulator valve 61 via the line 141.
By being introduced into this regulator valve 61
The line pressure adjusted by is increased according to the increase of the throttle opening. On the other hand, a line 142 branched from the retreat line 112 is connected to the second pressure increasing port 61b provided in the regulator valve 61. As a result, the line pressure is further increased in the R range.

In this embodiment, the duty control pressure generated by the first duty solenoid valve 90 for adjusting the engagement force of the lockup clutch 26 is the control port 9 of the accumulator modulator valve 93.
3a is also supplied. This modulator valve 93 is connected from the main line 110 to the line 143.
The line pressure supplied via the first solenoid valve 66 is adjusted in accordance with the duty control pressure from the first solenoid valve 66 to generate a modulator pressure, and the modulator pressure is supplied via the line 144 to the back of the NR accumulator 83. It is configured to supply the pressure chamber 83a and the like.

3-4 on the 3-4 clutch line 121
A line 145 branched from the line 144 is connected to the control port 77a of the 4-control valve 77. Therefore, if the first duty solenoid valve 90 is duty-controlled, a modulator pressure corresponding to the duty ratio D is generated by the accumulator modulator valve 93 and introduced into the control port 77a of the 3-4 control valve 77. Will be
3-4 adjusted by this control valve 77
The clutch pressure is also adjusted to a value corresponding to the duty ratio D.

On the other hand, the above 3-4 control valve 77
Is provided with a pressure regulation blocking port 77b for blocking the pressure reducing operation at one end side thereof, the pressure regulation blocking port 77b is provided, and the switching valve 94 and the line 146 are provided at the pressure regulation blocking port 77b. A pressure regulation prevention line 147 is connected to the main line 110 via the. When the pressure regulation blocking line 147 communicates with the line 146 via the switching valve 94, the line pressure of the main line 110 is supplied to the pressure regulation blocking port 77b of the 3-4 control valve 77, and this control is performed. The pressure adjusting operation of the valve 77 is blocked.

That is, the control port 94a on one end side of the switching valve 94 has the orifice 89 and the first duty solenoid valve 90 in the control pressure line 138.
A line 148 branched from the control pressure line 138 is connected to the balance port 94b on the other end side, and a line 149 branched from the control pressure line 138 is connected to the balance port 94b on the other end side. When the duty control pressure generated by the first duty solenoid valve 90 is equal to or higher than a predetermined value, the spool of the switching valve 94 is located on the left side in the drawing, and the pressure regulation blocking line 147 is the main line. 110 is connected to a line 146 leading to the main line 110.
The line pressure is supplied to the pressure regulation blocking port 77b of the 3-4 control valve 77, whereby the pressure regulation operation is blocked.

On the other hand, the first duty solenoid valve 9
When the duty control pressure generated at 0 falls below a predetermined value, the spool of the switching valve 94 overcomes the spring force or the like and moves to the right, whereby the pressure regulation blocking line 147 is disconnected from the line. A line 150 connected to the pressure regulation blocking line 147 when the spool is located to the right is connected to the switching valve 94. This line 150 is connected to the line 151 which is connected to the main line 110 via the line 133 when the spool is positioned to the left by being guided to the fourth shift valve 84 for lockup control.

That is, when the fourth solenoid valve 87 is in the ON state and the engagement force of the lockup clutch 26 can be controlled, the line pressure of the main line 110 is the lines 133, 151, the fourth shift valve 84, and the line 150. Will be guided to the pressure regulation prevention line 147 via. In the converter state in which the spool of the fourth shift valve 84 is located on the left side, the
The line 150 communicates with a drain port provided in the shift valve 84.

A drain line 151, which communicates with the servo apply line 118 when the spool of the first shift valve 63 is located on the right side, is connected to the switching valve 94. The drain line 151 is selectively communicated with two drain ports having different throttle amounts. In this embodiment, the drain port located on the right side of the drawing has a smaller throttle amount than that on the left side.

The first shift valve 63 is connected to the line 152 branched from the pressure regulation blocking line 147 for the 3-4 control valve, and the first solenoid valve 66 is turned on to the first shift valve 63. When the spool of the shift valve 63 is located on the left side, the first back pressure chamber 7
The second back pressure port 7 of the 1-2 accumulator 74 in which the line pressure of the main line 110 is constantly introduced from 4a.
The line 153 leading to 4b and the line 152 are configured to communicate with each other. Therefore, when the line pressure is supplied to the pressure regulation blocking line 147, this line pressure is applied to the line 152 and the line 153 only when the spool of the first shift valve 63 is located on the right side.
It is introduced into the second back pressure chamber 74b of the 1-2 accumulator 74 via the.

Further, an accumulation cut valve 73 is installed on a line 119 branched from the servo apply line 118 leading to the apply port 45b of the servo piston 45a and leading to the 1-2 accumulator 74. In this accumulation cut valve 73,
A line 154 branched from the 3-4 clutch line 121 on the downstream side of the 3-4 control valve 77 is connected to the control port 73a on the one end side thereof, and an accumulation cut prevention port 73b provided on the other end side.
A line 156 is connected to the pressure regulation block line 139 for blocking the pressure regulation of the lockup control valve 85 via the shuttle ball valve 95 and the line 155.

A line 157 branched from the line 126 connected to the second shift valve 64 is connected to the intermediate port 73c provided in the intermediate portion of the above-mentioned accumulation cut valve 73. The shuttle ball valve 95 connected to the line 156 leading to the accumulation cut prevention port 73b of the accumulation cut valve 73 is connected to a line 150 provided between the switching valve 94 and the fourth shift valve 84. The branched line 159 is connected.

In addition to the above construction, the hydraulic circuit 60 includes a fifth circuit mainly used for adjusting the shift timing.
A shift valve 96 is provided. The fifth shift valve 96 includes a first bypass line 160 that bypasses the orifice 72 on the servo apply line 118 and a one-way valve 82 on the reverse clutch line 130.
Is installed across the second bypass line 161 that bypasses the lockup control valve 85 and the lockup pressure regulation blocking line 139 guided to the pressure regulation blocking port 85b of the lockup control valve 85, and the control port 96a on one end side is installed.
A control pressure line 162 branched from the main line 110 is led to the. And this control pressure line 16
Turn on the 5th solenoid valve 97 installed in 2
By performing F control, the position of the spool of the fifth shift valve 96 is switched so that the first and second bypass lines 160 and 161 and the pressure regulation blocking line 139 are opened or closed.

That is, the fifth solenoid valve 97 described above.
Is off and the spool of the fifth shift valve 96 is located on the right side in the drawing, the first bypass line 1
The second bypass line 161 is cut off while the pressure control line 60 and the pressure regulation prevention line 139 are opened. At this time, the upstream portion of the second bypass line 161 communicates with the line 129 provided with the orifice 80 and the one-way orifice 81, and communicates with the reverse clutch line 130 or the reverse line 112 via this line 129. Also, the fifth solenoid valve 97
Is turned on and the spool of the fifth shift valve 96 moves to the left side in the drawing, the first bypass line 160 and the pressure regulation blocking line 139 are cut off, and the second bypass line 161 is opened. Become.

Further, the one-way orifice 9 located on the downstream side of the fifth shift valve 96 in the first bypass line 160 and performing a throttle action in the hydraulic oil supply direction.
8 is provided, and a normal orifice 99 is provided on the upstream side of the fifth shift valve 96.
In the branch line 163 branched from the first bypass line 160 on the upstream side of the orifice 99, the orifice 100 having a smaller throttle amount than the orifice 99 and the one-way valve that opens in the hydraulic oil discharge direction are provided. A valve 101 is provided. The branch line 163 is connected to the first bypass line 160 downstream of the fifth shift valve 96 when the fifth solenoid valve 97 is in the ON state and the spool of the fifth shift valve 96 is located on the left side. It is supposed to be merged.

As shown in FIG. 7, the automatic transmission 10 has first to third solenoid valves 66 to 6 for gear shift control.
8, a controller 200 for controlling the operation of the lockup fourth solenoid valve 87 and the first duty solenoid valve 90, the line pressure adjusting second duty solenoid valve 92 and the fifth solenoid valve 97.
Is provided.

The controller 200 includes a vehicle speed sensor 201 for detecting the traveling speed of the automobile, a throttle opening sensor 202 for detecting the throttle opening of the engine, and a shift position for detecting the position (range) of the shift lever of the automatic transmission 10. Operation is performed in response to signals from the sensor 203, the engine speed sensor 204 that detects the engine speed, the turbine speed sensor 205 that detects the turbine speed of the torque converter 20, and the oil temperature sensor 206 that detects the temperature of the hydraulic oil. It is configured to execute the control of each solenoid valve corresponding to the state and the driver's request.

The spring 167 provided on the pressure reducing valve composed of the solenoid reducing valve 88 as described above.
Of the hydraulic oil returned from the feedback circuit 169 to the one end 88a side of the solenoid reducing valve 88 is controlled so that the hydraulic pressure output to the feedback circuit 169 is controlled. In the hydraulic circuit of the automatic transmission configured as described above, since the pressure adjusting means 171 for increasing / decreasing the amount of hydraulic oil leaking from the feedback circuit 169 in proportion to the oil temperature is provided, the constant pressure is always maintained regardless of the oil temperature. The hydraulic oil can be output to the control valve including the throttle modulator valve 91.

That is, in the conventional apparatus, when the oil temperature in the hydraulic circuit rises and the viscosity thereof decreases when the automatic transmission operates, the feedback circuit 169 of the solenoid reducing valve 88 causes one end 88a of the valve. As the amount of hydraulic oil returned to the side increases,
There was a tendency that the Young's modulus of the spring 167 for urging the spring toward the one end portion 88a side was lowered and the urging force thereof was lowered.
Therefore, when the oil temperature is high, the spool 166 of the solenoid reducing valve 88 moves to the other end side, that is, the installation side of the spring 167, and the amount of hydraulic oil drained from the drain port 170 increases as compared with the normal time.
There has been a situation in which the hydraulic pressure output from the duty control line 168 decreases.

On the other hand, when the amount of hydraulic oil leaking from the feedback circuit 169 is increased or decreased in proportion to the oil temperature as described above, the solenoid reducing valve 88 of the solenoid reducing valve 88 is operated when the oil temperature is high. One end 88a
The amount of hydraulic oil returned to the side can be reduced. Therefore, it is possible to suppress a decrease in the working oil pressure due to a decrease in the Young's modulus of the spring 167, etc., and always output a constant working oil pressure to the feedback control circuit 168.

The hydraulic pressure output from the solenoid reducing valve 88 is adjusted as the duty control pressure by the second duty solenoid valve 92 and then supplied to the throttle modulator valve 91. The hydraulic pressure output from the throttle modulator valve 91 is adjusted as the throttle modulator pressure by the second duty solenoid valve 92 and then supplied to the first pressure increasing port 61a of the regulator valve 61. It As a result, the line pressure output from the regulator valve 61 is properly controlled to a value corresponding to the throttle opening of the engine, and the shift control is properly executed according to this line pressure.

In the above embodiment, the bimetal 174 is used.
The opening 17 of the passage communicating with the feedback circuit 169 by the closing plate 173 provided at one end of the
The example in which the pressure adjusting means 171 is provided to increase the amount of hydraulic oil leaking from the feedback circuit 169 in proportion to the oil temperature by changing the opening area of No. 2 has been described. However, various modifications are possible without being limited to the above-mentioned embodiment.

For example, as shown in FIGS. 8 and 9, the valve body 16 formed of an aluminum alloy or the like.
A stopper plug 175 made of steel is provided at one end of the valve body 5, and the stopper plug 175 and the valve body 16 are provided.
A gap h between the plug installation opening formed in FIG.
And the outer diameter d of the stopper plug 175 and its width dimension,
That is, by setting the passage length L of the gap h to an appropriate value, the amount of hydraulic oil leaking from the feedback circuit 169 to the outside of the solenoid reducing valve 88 via the gap h can be made to correspond to the oil temperature. It may be configured to change.

That is, the leak amount Q of the hydraulic oil is determined by the outer diameter d of the stopper plug 175,
It can be calculated based on the gap h, the passage length L, the viscosity μ of the hydraulic oil, and the pressure difference ΔP between the hydraulic oil inside and outside.

[0080] ^{Q = (πdh 3 / 12μL)} × the ΔP above equation, the viscosity of the hydraulic oil in response to an increase in oil temperature μ
It is understood that when the gap h decreases and the gap h increases, the leak amount Q of the hydraulic oil increases correspondingly.

Therefore, the gap h and the passage length L are set to proper values in advance, and the one end 88a side of the solenoid reducing valve 88 is provided in correspondence with the Young's modulus of the spring 167 which decreases when the oil temperature rises. By configuring so as to reduce the amount of hydraulic oil returned, the leak amount Q of the hydraulic oil can be increased in accordance with the increase in oil temperature. As a result, the hydraulic pressure output from the solenoid reducing valve 88 to the throttle modulator valve 91 can be automatically adjusted and maintained at a constant value.

Further, as shown in FIG. 10 and FIG.
Valve body 16 of solenoid reducing valve 88
A choke 177 communicating with the one end 88a of the No. 5 through the cast hole 176 is provided, and by setting the diameter D and the length N of the choke 177 to appropriate values, the feedback circuit 169 through the choke 177. The amount of hydraulic oil leaking to the outside may be changed according to the oil temperature.

That is, the leak amount Q of the hydraulic oil is expressed by the following formula: the diameter D of the choke 177, the length N thereof, the viscosity μ of the hydraulic oil, and the pressure difference ΔP between the inside and outside of the operating oil.
It can be calculated based on

[0084] Q = from (πD ⁴ / 128μN) × ΔP above equation, the viscosity μ of the hydraulic oil decreases in response to an increase in oil temperature, the leakage amount of the operating oil leaking from the choke 177 in response thereto It can be seen that Q increases.

Therefore, the diameter D and the length N of the choke 177 are set to appropriate values in advance, and one end side of the solenoid reducing valve 88 is made to correspond to the Young's modulus of the spring 167 which decreases when the oil temperature rises. By reducing the amount of hydraulic oil returned to 88a,
The leak amount Q of the hydraulic oil can be increased according to the increase in the oil temperature. As a result, the solenoid reducing valve 88 to the throttle modulator valve 9
The hydraulic pressure output to 1 can be automatically adjusted to maintain it at a constant value.

[0086]

As described above, according to the present invention, the feedback circuit for feeding back the hydraulic pressure output from the pressure reducing valve changes the amount of hydraulic oil leaking from the footback circuit according to the oil temperature. , Since the pressure adjusting means for adjusting the original pressure to a constant value is provided,
The pilot pressure and the like supplied to the regulator valve can be appropriately controlled by the control valve which is controlled according to the hydraulic pressure output from the pressure reducing valve.

Therefore, the line pressure output from the regulator valve is fluctuated, the shift control becomes unstable, the driving force of the oil pump is wasted, and the fuel consumption is deteriorated. There is an advantage that it can be prevented.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view showing an overall structure of an automatic transmission to which a hydraulic circuit according to the present invention is applied.

FIG. 2 is an explanatory diagram showing a configuration of a hydraulic circuit of the automatic transmission.

FIG. 3 is a circuit configuration diagram showing a main part of the hydraulic circuit.

FIG. 4 is a perspective view showing a configuration of a pressure adjusting means provided in the hydraulic circuit.

FIG. 5 is a plan view showing an operating state of the pressure adjusting means.

FIG. 6 is a plan view showing an operating state of the pressure adjusting means.

FIG. 7 is a block diagram showing a configuration of a control unit provided in a hydraulic circuit.

FIG. 8 is a cross-sectional view showing another example of the pressure reducing valve.

FIG. 9 is a sectional view showing another example of the pressure adjusting means.

FIG. 10 is an explanatory view showing still another example of the pressure adjusting means.

FIG. 11 is a cross-sectional view showing a specific structure of the source pressure adjusting circuit.

FIG. 12 is a graph showing the relationship between line pressure and duty control pressure.

[Explanation of symbols]

 10 Automatic Transmission 13 Oil Pump 60 Hydraulic Circuit 61 Reducing Valve 88 Solenoid Reducing Valve (Decompression Valve) 91 Throttle Modulator Valve (Pressure Control Valve) 169 Feedback Circuit 171 Pressure Adjusting Means

Claims (2)

[Claims] 1. A pressure reducing valve for reducing the pressure of hydraulic oil discharged from an oil pump to a preset constant value, a feedback circuit for feedback controlling the hydraulic pressure output from the pressure reducing valve, and a leak from this feedback circuit. A hydraulic circuit for an automatic transmission, comprising: pressure adjusting means for adjusting the operating oil pressure to a constant value by changing the amount of operating oil according to the oil temperature. 2. A regulator valve that regulates the line pressure of a hydraulic circuit, a control valve that controls the pilot pressure of the regulator valve, a pressure reducing valve that generates the original pressure of the control valve, and an operation that is output from the pressure reducing valve. A feedback circuit for feedback controlling hydraulic pressure,
A hydraulic circuit for an automatic transmission, comprising: pressure adjusting means for adjusting the operating hydraulic pressure to a constant value by changing the amount of hydraulic oil leaking from the feedback circuit in accordance with the oil temperature.