JPH08296725A - Hydraulic control device for automatic transmission - Google Patents

Abstract

PURPOSE: To eliminate the necessity of a solenoid valve used exclusively for the control of a cutback valve in order to reduce the cost of a device by controlling the cutback valve at a high speed stage pressure at high stages over as specified limit and at a signal pressure from a lockup solenoid valve at low speed stages where cutback control is needed. CONSTITUTION: A hydraulic control device for automatic transmission is provided with a lockup control valve 52, a pressure regulator valve 40, and a cutback valve 5 for outputting a cutback signal pressure to a pressure regulator valve 40. Also, when a vehicle is shifted to a position where the cutback control is not needed, for example, to a third gear position, the hydraulic pressure of a band brake produced at that time is applied to the first control port 54a of the cutback valve 54 so as to move a spool to a position where a line pressure PL as a cutback signal pressure is shielded. On the other hand, in the first and second gear positions where the vehicle needs the cutback control, the cutback valve 54 is switched over according to the existence of signal pressures from a lockup solenoid valve 56.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control device for an automatic transmission.

[0002]

2. Description of the Related Art As a conventional hydraulic control device for an automatic transmission, there is, for example, one disclosed in Japanese Patent Laid-Open No. 59-103056. The hydraulic control device for the automatic transmission shown therein has a dedicated solenoid valve for controlling the cutback valve. That is, when there is an input (manipulation of the manual valve) by the driver, the electronic control device operates the solenoid valve for cutback control under the set vehicle traveling conditions. As a result, the cutback signal pressure from the cutback valve is shut off by the dedicated solenoid valve and is not input to the regulator valve, so that the line valve pressure reducing operation (cutback operation) by the regulator valve is stopped. Has become. That is, during the manual control, even if the vehicle speed is higher than a predetermined value, the line pressure is maintained at a predetermined value without being reduced, and the multi-disc brake and the multi-disc clutch are kept above the predetermined value. The large torque required to start the vehicle at the high gear position is transmitted.

[0003]

However, in the conventional hydraulic control system for an automatic transmission as described above, a dedicated solenoid valve is provided to control the cutback valve, and therefore the price of the system is low. There is a problem that is high. The present invention aims to solve such problems.

[0004]

The present invention solves the above problems by utilizing a lockup solenoid for lockup control of a torque converter for controlling a cutback valve. That is, the hydraulic control device for an automatic transmission according to the present invention as set forth in claim 1 is intended for one having a torque converter (10) with a lockup clutch, and a lockup control for controlling lockup of the torque converter (10). Valve (52), lock-up solenoid (56) for controlling the lock-up control valve (52), pressure regulator valve (40) for adjusting the line pressure (PL) of the hydraulic circuit, and pressure regulator for cutback signal pressure. And a cutback valve (54) for outputting to the valve (40), the cutback valve (54) has a predetermined high speed stage pressure ( Low speed stage that requires cutback control while being controlled by 3R pressure or 4A pressure) Oite is,
It is characterized in that it is configured to be controlled by the signal pressure from the lock-up solenoid (56). The hydraulic control device for an automatic transmission according to a second aspect of the present invention is the output port (54c) of the cutback valve (54) and the pressure regulator valve (4).
Oil passage (78) connecting to the control port (40a) of 0)
Is provided with a shuttle valve (74), and one input port (74a) of the shuttle valve (74) is the output port (54c) of the cutback valve (54).
, The other input port (74b) of the shuttle valve (74) is connected to the reverse pressure (R pressure) oil passage, and the output port (74c) of the shuttle valve (74) is connected to the pressure regulator valve ( 40) above control port (4
0a). The reference numerals in the parentheses indicate the corresponding members in the embodiments.

[0005]

According to the first aspect of the present invention, at a predetermined speed or higher (for example, the third speed) that does not require cutback control, the cutback valve is generated by the high speed pressure (for example, 3R pressure) generated by the shift. However, since the signal pressure is switched to the position where it is cut off, the signal pressure does not act on the pressure regulator valve even when the lockup solenoid is generating the signal pressure. As a result, the pressure regulator valve controls the line pressure so as to regulate the line pressure at a low pressure. Further, in the torque converter, the lockup clutch is released / engaged according to the presence or absence of the signal pressure from the lockup solenoid. On the other hand, at low speeds below a predetermined level (for example, the second speed) where cutback control is required, the high speed pressure does not occur, but in this case, the signal pressure from the lockup solenoid is reduced. The cutback valve is switched and controlled depending on the presence or absence. First, when the signal pressure of the lockup solenoid is generated, this signal pressure is introduced into the control port of the cutback valve, so that the cutback valve drains the cutback signal pressure to the pressure regulator valve. The pressure regulator valve is controlled to control the pressure without increasing the line pressure as usual. Further, the signal pressure from the lockup solenoid acts on the control port of the lockup control valve as the lockup signal pressure, so that the lockup of the torque converter is released. Next, when the signal pressure of the lockup solenoid is not generated, the signal pressure does not act on the control port of the cutback valve. Therefore, the cutback valve is switched to the position where the line pressure communicates with the pressure regulator valve by the force of the spring. As a result, line pressure is introduced into the control port of the pressure regulator valve, and the pressure regulator valve
The line pressure is controlled to be adjusted to a high pressure without being reduced. Moreover, since the pilot pressure acts on the control port of the lockup control valve, the lockup of the torque converter is released. By doing so, the cutback control can be performed without providing a dedicated solenoid valve for controlling the cutback valve, so that the apparatus can be made inexpensive. According to the second aspect of the invention, the pilot pressure or the reverse pressure, whichever is larger, is selected by the shuttle valve and introduced into the control port of the pressure regulator valve. Cutback control is also possible.

[0006]

【Example】

(First Embodiment) FIG. 1 shows a hydraulic circuit of a hydraulic control device according to the present invention. FIG. 2 shows a gear shift mechanism that should be shift-controlled by this system. This hydraulic control system includes a pressure regulator valve 40, a pressure modifier valve 42,
Line pressure solenoid 44, modifier pressure accumulator 46, pilot valve 48, torque converter relief valve 50, lockup control valve 52, cutback valve 54, lockup solenoid 56, manual valve 5
8, first shift valve 60, second shift valve 62, first shift solenoid 64, second shift solenoid 66, 2-3 control valve 68, flow regulator valve 70, 5-2 sequence valve 72, first reducing valve 76 , Overrun clutch control valve 80, overrun clutch solenoid 82, overrun clutch reducing valve 84, ND accumulator 92, accumulator control valve 94, filter 96, reduction brake 13, direct clutch 32, reduction timing valve 104, reduction shift valve 106, reduction brake accumulator 108, 5-speed servo apply reducing valve 110, 5-speed servo apply accumulator 112 and 114, third shift solenoid 11
6, direct clutch accumulator 118, accumulator switching valve 120, OD / A accumulator 122
And the like, which are connected to each other as shown in the drawing, and the torque converter 10 (which includes the lock-up clutch apply chamber 11a and the release chamber 11).
b), the reverse brake 18, the high clutch 20, the forward clutch 22, the overrun clutch 24, the low and reverse brake 26, and the band brake 28 (here, the second speed apply chamber 28).
Release chamber 28b for 3rd speed, and apply chamber 2 for 4th speed
8c is also formed) and a variable capacity vane type oil pump 34 and an oil pump 3 each having a feedback accumulator 33.
5, the oil cooler 36, the front lubrication circuit 37, and the rear lubrication circuit 38 are also connected as shown. Next, the connection relationship of members such as valves related to the present invention will be described in a little more detail. Normally, the control port 52a at the lowermost stage in FIG. 1 of the lockup control valve 52 is directly connected to the control port 56a of the lockup solenoid 56 through the oil passage 130. However, in the present invention, the cutback valve 54 is used as the cutback valve 54. It is provided in the middle of the oil passage 130. That is, the control port 52a of the lock-up control valve 52 and the control port 56a of the lock-up solenoid 56 are located at the lower position below the illustrated position against the spring force of the spool of the cutback valve 54. When the spool is located at the rising position shown in the drawing, the spool is disconnected. Similarly, the third output port 54c from the bottom in FIG. 1 of the cutback valve 54 and the pressure regulator valve 40
1 is communicated with the third control port 40a from the bottom in FIG. 1 when the spool of the cutback valve 54 is located at the illustrated rising position, and when the spool is located at the descending position against the spring force. It is configured to be shut off. The control port 56a of the lock-up solenoid 56 has an oil passage 132, and the third pilot pressure oil chamber 5 of the lock-up control valve 52 in FIG.
Always in communication with 2b. Next, the gear shift mechanism will be described. The input shaft 201 and the output shaft 202 are arranged in a coaxial butting relationship. A main planetary gear mechanism (main transmission mechanism) 203 is concentrically arranged on the input shaft 201, and a sub-planetary gear mechanism (sub transmission mechanism) 204 is concentrically arranged on the output shaft 202. Main planetary gear mechanism 203
In 1987, issued by Nissan Motor Co., Ltd. "Automatic transmission RE4R01A type maintenance manual (A26
1C07), which is the same as the transmission mechanism described on pages 1 to 53, and includes two first and second planetary gear sets 2
05 and 206 are provided in a tandem, and these are respectively a first sun gear 205S, a second sun gear 206S, a first ring gear 205R, a second ring gear 206R, a first pinion 205P and a second pinion 206 meshing with each gear.
P and the first that rotatably supports both pinions
It is a simple planetary gear set including a carrier 205C and a second carrier 206C. The first sun gear 205S is
It can be fixed by the band brake 28, and can be connected to the input shaft 201 by the reverse clutch 12. The first carrier 205C is connectable to the input shaft 201 by the high clutch 20 and is also connected by the low one-way clutch 14.
It is impossible to rotate in the opposite direction, and it can be fixed by the low and reverse brake 26. The first carrier 205C can be coupled to the outer race of the forward one-way clutch 30 arranged in the same direction as the low one-way clutch 14 by the forward clutch 22, whereby the inner race of the forward one-way clutch 30 can be changed to the first race. It can be coupled to the two ring gear 206R. Further, the second ring gear 206R can be coupled to the first carrier 205C by the overrun clutch 24, and thus the second sun gear 206S can be coupled to the input shaft 201. The sub-planetary gear mechanism 204 includes a third planetary gear set 207, which includes a third sun gear 207S and a third ring gear 20.
7R, a third pinion 207P that meshes with both gears, and a third planetary gear set 207C that rotatably supports the third pinion 207P. The second carrier 206C which is an output element of the main planetary gear mechanism 203
The third ring gear 207R is coupled to the third carrier 20
7C is coupled to the output shaft 202. Furthermore, the third ring gear 207R is appropriately set to the third ring gear 207R by the direct clutch 32.
The third sun gear 207S can be coupled to the sun gear 207S, and the third sun gear 207S can be prevented from rotating in the direction opposite to the input shaft 201 by the reduction brake 13 and can be appropriately fixed by the reduction brake 13.

FIG. 3 shows the configuration around the cutback valve as a first embodiment. The cutback valve 54 has two control ports for controlling the spool thereof, that is, a first control port 54a to which the 3R pressure (hydraulic pressure acting on the third speed release chamber 28b) from the band brake 28 is introduced, and It has a second control port 54b into which the signal pressure from the lockup solenoid 56 is introduced. The spool 55 of the cutback valve 54 is acted by a spring 55 in the rightward direction in the drawing. Now, for example, in the case of the third speed to the fifth speed (higher speed than a predetermined speed),
3R pressure from the band brake 28 (3rd speed release chamber 2
Hydraulic pressure acting on 8b) acts on the first control port 54a, and the spool is fixed to the left position in the figure against the force of the spring 55, the control port 40a of the pressure regulator valve 40 has a line pressure. The PL is drained without being introduced, and at the same time, the signal pressure from the lockup solenoid 56 is introduced into the control port 52a of the lockup control valve 52. In addition, the first control port 54a of the cutback valve 54
In the case of the 1st speed or the 2nd speed (low speed lower than a predetermined level) where the 3R pressure does not act on, the cut is performed in the same manner as above only when the signal pressure from the lockup solenoid 56 acts on the second control port 54b. The spool of the back valve 54 will be pushed to the left position in the figure.

Next, the operation of the automatic transmission will be described. First, the main planetary gear mechanism 203 will be described with reference to FIG. When the forward clutch 22 is actuated, this prevents the second ring gear 206R from rotating in the direction opposite to the input shaft 201 via the forward one-way clutch 30 and the low one-way clutch 14. Therefore, the power from the input shaft 201 to the second sun gear 206S is
The pinion 206P is rolled in the second ring gear 206R, and the second carrier 206C is decelerated in the same direction as the input shaft 201 to be in the first speed state in which it is normally rotated. In this first speed state, when the second carrier 206C is reversely driven in the same direction as the input shaft 201 at a high speed, both one-way clutches 30 and 14 are driven.
The reverse driving force is not transmitted to the input shaft 201 due to the release of
I can't get engine braking. If engine braking is required, the overrun clutch 24 and the low and reverse brake 26 must be activated to prevent both one-way clutches 30 and 14 from releasing. When the forward clutch 22 and the band brake 28 are operated, the first sun gear 205S is fixed by the band brake 28 and receives a reaction force, and the forward clutch 22 and the forward one-way clutch 3
In combination with the operation of 0, the power from the input shaft 201 to the second sun gear 206S causes the second carrier 206C to rotate normally at a higher speed than the first speed state, and the second speed state is obtained. When the forward one-way clutch 30 is released in the second speed state, the reverse driving force is not transmitted to the input shaft 201 and engine braking cannot be obtained. If engine braking is required, the overrun clutch 24 must be activated to prevent the forward one-way clutch 30 from releasing. Forward clutch 22 and high clutch 2
When 0 is actuated, the second ring gear 206
R rotates together with the input shaft 201, and the second sun gear 206S and the second ring gear 206R coupled to the input shaft 201 rotate integrally with each other, whereby the second carrier 2
The third speed (direct connection) state in which 06C makes the same rotation as the input shaft 201 is obtained. Even in this state, the reverse driving force is not transmitted to the input shaft 201 by releasing the forward one-way clutch 30, and engine braking cannot be obtained. If engine braking is required, the overrun clutch 24 must be activated to prevent the forward one-way clutch 30 from releasing. When the high clutch 20 and the band brake 28 are operated, the first clutch 205C rotates together with the input shaft 201 by the operation of the high clutch 20, and the first sun gear 205S is fixed by the operation of the band brake 28. Through the rolling of the first pinion 205P on the sun gear 205S, the first ring gear 205R, and thus the second carrier 206C, is normally rotated in the increased speed state to be in the fourth speed state. In the fourth speed state, the forward one-way clutch 30 operates so that there is no problem even when the forward clutch 22 is still operating.
Make sure to keep 2 activated. When the reverse clutch 12 and the low and reverse brake 26 are actuated, the operation of the reverse clutch 12 causes the first sun gear 205S to rotate together with the input shaft 201, and the operation of the low and reverse brake 26 causes the first carrier 2 to move.
Since 05C is fixed, the first ring gear 205R, and thus the second carrier 206C, is rotated in the direction opposite to the input shaft 201 and is in the retracted state. Next, the sub-planetary gear mechanism 204 will be described. When the reduction brake 13 is operated, the third sun gear 207S is fixed and the second sun gear 207S is fixed.
Rotational power from the carrier 206C to the third ring gear 207R causes the third pinion 207P to move to the third sun gear 207S.
While being rolled around, it is transmitted to the third carrier 207C, and thus to the output shaft 202 in a decelerated state, and a decelerated state is obtained. Accordingly, the sub planetary gear mechanism 204 functions as a low speed selecting friction element. When the direct clutch 32 is operated, the third sun gear 207S is coupled to the third ring gear 207R, and the second carrier 20
It is possible to obtain a direct connection state in which the rotational power of 6C is directly transmitted from the third carrier 207C to the output shaft 202.
As a result, the sub-planetary gear mechanism 204 functions as a friction element for high speed selection. When switching the reduction brake 13 from the operating state to the non-operating state,
Before the operation of the direct clutch 32, the third sun gear 20
7S is the second carrier 206C and the third ring gear 207.
Rotating in the opposite direction to R not only accelerates the wear of the direct clutch 32, but also increases the shock when actuating the direct clutch 32 (which causes a shift shock). Since the reduction one-way clutch 16 prevents such rotation of the third ring gear 207R, it is possible to reduce shift shock. In the reduction one-way clutch 16, there is a case where it is not necessary to operate the reduction brake 13, but the sub-planetary gear mechanism 204 is set only in two states in which the direct clutch 32 or the reduction brake 13 is operated, and a high / low speed switching circuit is provided. For simplification, the reduction brake 13 is operated even when it is not necessary to operate it. As described above, the main transmission mechanism 203 is maintained in the third speed (direct connection) state and the auxiliary transmission mechanism 204 is set in the direct connection state, whereby the fourth speed (direct connection speed stage) having the gear ratio of 1 is achieved. The fifth speed can be obtained by maintaining the auxiliary transmission mechanism 204 in the direct connected state and setting the main transmission mechanism 203 in the fourth speed (acceleration) state.

Next, the operation of the hydraulic control system according to the first embodiment of the present invention will be described. Now, assuming that the vehicle is shifted to, for example, the third speed out of the third speed to the fifth speed that does not require cutback control, as shown in FIG.
The 3R pressure of the band brake 28 generated due to the speed shift acts on the first control port 54a of the cutback valve 54, and the spool thereof resists the force of the spring 55 to the left position shown in FIG. That is, since the line pressure PL as the cutback signal pressure is moved to a position where it is cut off, the pressure regulator valve 40 is drained without introducing the line pressure PL to its control port 40a. As a result, the line pressure PL is controlled in a reduced pressure state. At the same time, the control port 52a of the lockup control valve 52 is connected to the lockup solenoid 5
6 is in communication with the signal pressure oil passage, and the lockup solenoid 56 is in the energized ON state (a state in which the ON time ratio of the energized ON / OFF signal is increased in duty driving).
The lock-up clutch is engaged or disengaged depending on whether the lock-up clutch is in the ON state or the energized state is OFF (state in which the OFF time ratio of the ON / OFF signal is increased). When the vehicle is in the first speed or the second speed that requires cutback control, the 3R pressure is not generated from the band brake 28, but instead of this, the lockup solenoid 56 sends the signal of this signal. The cutback valve 54 is switched and controlled according to the presence or absence of pressure. First, when the lock-up solenoid 56 is in a power-off state, the control port 56a of the lock-up solenoid 56 is closed to generate a signal pressure, and the signal pressure is generated by the second control port 54b of the cutback valve 54.
Will be introduced to. As a result, the cutback valve 54 is switched to the left side position shown in FIG. 3, and the pressure regulator valve 40 has its control port 40a provided with the line pressure P.
Drained without introducing L. As a result, the pressure regulator valve 40 controls the line pressure PL to a reduced state. Further, since the signal pressure from the lockup solenoid 56 is introduced as the lockup signal pressure into the control port 52a of the lockup control valve 52, the lockup of the torque converter 10 is released. Next, when the lock-up solenoid 56 is energized, the control port 56a of the lock-up solenoid 56 is opened to the drain, so that no signal pressure is generated. Therefore, the cutback valve 54 has both control ports 54
Since the hydraulic pressure does not act on either a or 54b, the spool thereof is switched to the right side position shown in FIG. 3 by the force of the spring 55. As a result, the line pressure P is applied to the control port 40a of the pressure regulator valve 40.
L is introduced, and the pressure regulator valve 40 controls to increase the line pressure PL. Further, since the pilot pressure PP is introduced into the control port 52a of the lockup control valve 52, the lockup of the torque converter 10 is released. The above operation is summarized as shown in FIG. in short,
In the case of the first speed or the second speed, the cutback valve 54 is
Switching control is performed by the lockup solenoid 56. By doing so, the cutback valve 54
Since the cutback control can be performed without providing a dedicated solenoid valve for switching control of the device, the device can be made inexpensive. Note that in FIG. 7, LU
Indicates lockup, SOL indicates the signal pressure of the lockup solenoid, and Pilot indicates pilot pressure PP.

Next, FIG. 4 shows a part of a hydraulic control system according to a second embodiment of the present invention. The second embodiment is a case where the torque converter 10 is configured so as not to lock up at the third speed or lower, and the cutback valve 54 is used.
Is configured to be controlled by the 4A pressure (the hydraulic pressure acting on the fourth speed apply chamber 28c) instead of the 3R pressure of the first embodiment in the fourth speed and the fifth speed that do not require the cutback control. ing. A shuttle valve 74 is provided in an oil passage 78 that connects one output port 54c of the cutback valve 54 and the control port 40b of the pressure regulator valve 40.
Is provided. Of the two input ports of the shuttle valve 74, one input port 74a is connected to the cutback valve 5
4 is connected to one of the output ports 54c, and
The other input port 74b of the shuttle valve 74 is connected to the reverse pressure (R pressure) oil passage of the manual valve 58, and the output port 74c of the shuttle valve 74 is connected to the control port 40a of the pressure regulator valve 40. ing. In FIG. 4, the pilot pressure PP is connected to the pressure regulator valve 40 side, and the line pressure PL is connected to the lockup control valve 52 side via the cutback valve 54, respectively. However, the pilot pressure PP and the line pressure PL may be interchanged and connected. Of the pilot pressure PP and the reverse pressure R, the operation of the second embodiment is
Whichever is greater is selected by shuttle valve 74 to control port 4 of pressure regulator valve 40.
0a, except that the reverse pressure R applies a signal pressure to the control port 40a of the pressure regulator valve 40 to increase the line pressure PL even when the vehicle reverses. The same as in the first embodiment.

Next, FIG. 5 shows a third embodiment of the present invention.
This third embodiment is applicable to the case where the lockup control valve 52 is configured to be locked up when a signal pressure acts thereon and released when the signal pressure is released to the drain. It is something. The cutback valve 54 cuts off the signal pressure oil passage of the lockup solenoid 56 and the control port 52a of the lockup control valve 52 from the third speed to the fifth speed.
Through the first and second speeds,
When the lockup solenoid 56 is in the off state,
While the signal pressure of the control port 52a of the lockup control valve 52 is drained, the line pressure PL is applied to the control port 40a of the pressure regulator valve 40. The third embodiment is different from the first and second embodiments in that the cutback valve 54
Since the number of oil passages connected to 1 is small, the cost of the device can be reduced.

Next, FIG. 6 shows a fourth embodiment of the present invention.
In the fourth embodiment, the cutback signal pressure is used as the output pressure from the lockup solenoid 56, and the line pressure PL can be controlled to a pressure corresponding to this output pressure. Further, only one control port 54a is formed in the cutback valve 54, and 3R pressure is introduced into this. The fourth embodiment is the first
Compared with those of the first to third embodiments, the number of control ports of the cutback valve 54 is reduced by one, so that the price of the device can be further reduced.

In the above description of the second embodiment, the torque converter 10 is configured so as not to lock up at the third speed, but it is configured to lock up at the third speed. When the second embodiment is applied to the cutback valve 5 instead of the 4A pressure, the 3R pressure is used.
No. 4 first control port 54a may be supplied.

[0014]

As described above, according to the present invention as set forth in claim 1, the cutback valve can be switched and controlled by the lockup solenoid in the case of the low speed stage where the cutback control is required. Since it is not necessary to provide a dedicated solenoid for controlling the cutback valve, the price of the device can be reduced. Further, according to the present invention as set forth in claim 2, the pilot pressure or the reverse pressure, whichever is larger, is selected by the shuttle valve and introduced into the control port of the pressure regulator valve. In addition to the effect of the first aspect, the cutback control can be performed even when the vehicle moves backward.

[Brief description of drawings]

FIG. 1 is a diagram showing a hydraulic circuit of a hydraulic control device of the present invention.

FIG. 2 is a diagram showing a gear transmission mechanism.

FIG. 3 is a diagram showing a connection relationship of the cutback valve according to the first embodiment of the present invention.

FIG. 4 is a diagram showing a connection relationship of a cutback valve according to a second embodiment of the present invention.

FIG. 5 is a diagram showing a connection relationship of a cutback valve according to a third embodiment of the present invention.

FIG. 6 is a diagram showing a connection relationship of a cutback valve according to a fourth embodiment of the present invention.

FIG. 7 is a diagram illustrating the relationship between the operation of a lockup solenoid and lockup and cutback.

[Explanation of symbols]

 10 torque converter (with lock-up clutch) 13 reduction brake 14 low one-way clutch 16 reduction clutch 30 forward one-way clutch 40 pressure regulator valve 40a control port 52 lock-up control valve 52a control port 54 cutback valve 54a first control port 54b second Control port 55 Spring 56 Lock-up solenoid 58 Manual valve 74 Shuttle valve 203 Main transmission mechanism 204 Sub transmission mechanism 207 Third gear mechanism PL Line pressure PP Pilot pressure R Reverse pressure

Claims (2)

[Claims] 1. A hydraulic control device for an automatic transmission having a torque converter with a lockup clutch, comprising: a lockup control valve for controlling lockup of the torque converter; and a lockup solenoid for controlling the lockup control valve. A pressure regulator valve that adjusts the line pressure of the hydraulic circuit, and a cutback valve that outputs the cutback signal pressure to the pressure regulator valve. The high-speed stage is controlled by a predetermined high-speed stage pressure, while the low-speed stage requiring cutback control is controlled by the signal pressure from the lock-up solenoid. Hydraulic control device for automatic transmission. 2. A shuttle valve is provided in an oil passage connecting one output port of the cutback valve and a control port of the pressure regulator valve, and the shuttle valve has a cutback at one input port thereof. The valve is connected to the one output port of the valve, the other input port of the shuttle valve is connected to the reverse pressure oil passage, the output port of the shuttle valve is connected to the control port of the pressure regulator valve, The hydraulic control device for an automatic transmission according to claim 1, wherein: