JP2864858B2 - Hydraulic control device for automatic transmission for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control system for an automatic transmission for a vehicle, and more particularly to a hydraulic control system for a vehicle when a predetermined condition is satisfied even when a shift range is set to a forward drive range. Release the clutch (clutch that is engaged to achieve forward running) through the control valve (including substantial release by reducing oil pressure) to form a neutral state to prevent creep from occurring and at the same time brake control The present invention relates to a hydraulic control device for an automatic transmission for a vehicle, which prevents a vehicle from moving backward by engaging a brake for forming an engine brake at a predetermined speed through a valve.

[0002]

2. Description of the Related Art Conventionally, in an automatic transmission for a vehicle, if a shift range is set to a driving range such as a drive range, even if the vehicle speed is substantially zero, the gear of the automatic transmission will The transmission is set to the first speed (or the second speed) without being in the neutral state. Therefore, the output of the internal combustion engine is always transmitted to the forward clutch of the gear transmission via the torque converter, so that so-called creep occurs. As a result, in order to keep the vehicle stopped, the brake pedal must be depressed. I needed to.

[0003] Further, the drag of the torque converter at this time deteriorates the fuel consumption efficiency, and further causes a problem that the temperature of the hydraulic oil of the torque converter rises.

In view of the above, a control valve for controlling the hydraulic pressure of the forward clutch is newly provided. When the accelerator pedal is released and the vehicle is substantially stopped, the shift range is set to the drive range. Even when the vehicle is in the forward running range, the forward clutch is released via the control valve to automatically form a neutral state to prevent the occurrence of creep and improve fuel consumption efficiency. There is known a technique for suppressing a rise in the temperature of hydraulic oil of a torque converter (for example, Japanese Patent Application Laid-Open No. 63-1064).
49).

In general, when such a transition control to the neutral state (hereinafter referred to as creep reduction control) is performed, the vehicle can be prevented from retreating on a slope or the like in order to prevent the vehicle from retreating. A so-called hill hold control for engaging the brake (in the hydraulic control device) is also performed.

In order to better understand the present invention,
A specific example of an automatic transmission configured to perform such creep reduction control and hill hold control will be described in some detail.

FIG. 6 shows an overall outline of an automatic transmission for a vehicle. This automatic transmission includes a torque converter section 20, an overdrive mechanism section 40, and an underdrive mechanism section 60 having three forward stages and one reverse stage.

The torque converter section 20 includes a pump 2
1, a turbine 22, a stator 23, and a lock-up clutch 24.
Is transmitted to the overdrive mechanism 40.

The overdrive mechanism 40 includes a sun gear 43, a ring gear 44, a planetary pinion 42,
And a set of planetary gear units consisting of
The rotational state of the planetary gear unit is controlled by a clutch C0, a brake B0, and a one-way clutch F0.

The underdrive mechanism 60 includes two sets of planetary gear units including a common sun gear 61, ring gears 62 and 63, planetary pinions 64 and 65, and carriers 66 and 67. The rotation state and the connection state with the overdrive mechanism 40 are controlled by clutches C1, C2, brakes B1 to B3, and one-way clutches F1, F2.

The automatic transmission includes the above-described transmission unit and a computer 84. The computer 84 has a throttle sensor 80 for detecting a throttle opening θ for reflecting the load of the engine 1 and a vehicle speed N.
Signals for various controls such as a vehicle speed sensor (rotation speed sensor of the output shaft 70) 82 for detecting 0 and a C0 rotation speed sensor 99 for detecting the rotation speed of the clutch C0 are input.

The computer 84 controls the hydraulic control circuit 8 in accordance with a preset throttle opening-vehicle speed shift point map.
The solenoid valve in 6 is driven and controlled, and the shift is executed by performing a combination of engagement of each clutch and brake as shown in FIG.

Here, the clutch C1 corresponds to a forward clutch released during creep reduction control, and the brake B1 corresponds to a brake engaged during hill hold control.

When the shift range is in the forward running range, the forward clutch C1 is normally in the engaged state,
The vehicle is ready for forward running. However, even if the shift range is the forward running range, the throttle opening θ
Is zero (or the idle contact is ON) and the vehicle speed is zero (including substantially zero), the engagement pressure of the clutch C1 is reduced to shift the automatic transmission to a neutral state. At the same time as (creep reduction control), the brake B1 is engaged to activate the hill hold function (hill hold control).

Next, an example of a hydraulic control device for executing creep reduction control and hill hold control will be described with reference to FIGS.

In the drawing, reference numeral 110 denotes a manual shift valve. This manual shift valve 1
10 has a hydraulic input port 114. The hydraulic pressure input port 114 is supplied with a line pressure PL sucked up by an oil pump 120 and regulated by a primary regulator valve 124 via an oil passage 126.

The manual shift valve 110 has a spool 112 driven by a manual shift lever (not shown), and connects a hydraulic input port 114 to a D range port 116 when the manual shift range is the D range. When the manual shift range is the S range (two ranges), the hydraulic input port 114
To the S range port 118.

D range port 116 is connected to oil passages 300, 30.
The S range port 118 is connected to the port 146 of the 2-3 shift valve 140 through the oil passage 304.
−3 is connected to the port 148 of the shift valve 140.

The 2-3 shift valve 140 is provided on the spool 1
42. When no hydraulic pressure is supplied to the port 144, the spool 142 is in the raised position shown in the right half of the drawing, and connects the port 146 to the port 150,
In addition, the port 148 communicates with the port 152.

On the other hand, when the hydraulic pressure is supplied to the port 144, the port 144 is at the lower position shown in the left half of the figure, and the communication between the port 146 and the port 150 is cut off. Cut off,
The port 152 communicates with the drain port 154.

The supply of hydraulic pressure to the port 144 is performed by a solenoid valve (not shown) in a known manner, and the hydraulic pressure is supplied to the port 144 only when the third speed or the overdrive speed (fourth speed) is achieved. It has become so. Therefore, the spool 142 is at the raised position when the first speed or the second speed is achieved, and is at the lowered position when the third speed or the overdrive speed is achieved.

The port 150 is connected to a port 186 of the B1 control valve 180 by an oil passage 306. The port 152 is connected to the port 172 of the check valve 170 via the oil passage 308, the second coast modulator valve 160, and the oil passage 310.

The check valve 170 is connected to the inlet port 17.
In addition to the inlet port 174 and the outlet port 174, when an oil pressure is supplied to the inlet port 172 by the action of the check ball 178, the inlet port 174 is closed. When the hydraulic pressure is supplied to the inlet port 172, the inlet port 172 is closed.

The inlet port 174 is connected to the
1 The outlet port 176 is connected to the port 188 of the control valve 180, and the outlet port 176 is connected to the port 136 of the 1-2 shift valve 130 by an oil passage 314.

The 1-2 shift valve 130 has a spool 13
2 When hydraulic pressure is not supplied to the port 134, the spool 132 is in the raised position shown in the left half of the figure and communicates the ports 136 and 138. On the other hand, when hydraulic pressure is supplied to the port 134, the right half of the figure is The port 136 is disconnected from the drain port 139 by shutting off the ports 136 and 138 at the lower position shown in FIG.

A hydraulic pressure is supplied to the port 134 only when the first speed is achieved by the action of a solenoid valve (not shown).
Thus, the spool 132 is set to the raised position when the second speed, the third speed, or the overdrive speed is achieved, and is set to the lowered position only when the first speed is achieved.

The port 138 is connected to the brake B1 by an oil passage 316.

The B1 control valve 180 has a spool 182 and a plug 184. When the spool 182 is in the raised position shown in the right half of FIG.
86 and 188 and ports 190 and 192
And the port 192 is communicated with the drain port 198.

On the other hand, when in the lowered position shown in the left half of the figure, the port 186 is closed and the port 18 is closed.
8 to the drain port 187 and the port 190
And 192 are communicated.

Port 190 is connected to oil passage 314 and oil passage 300
Is connected to the D range port 116 of the manual shift valve 110, and the port 192 is connected to the port 208 of the C1 control valve 200 by an oil passage 316.

The spool 182 has ports 194 and 196
Driven by hydraulic pressure applied to ports 194 and 1
96, a signal oil pressure P equal to or more than a predetermined value Psset.
When s is supplied, it is located at the left half position, that is, the hill hold control release position. Also, port 194
And 196, the signal oil pressure Ps equal to or more than the predetermined value Psset
Is not supplied, the position is at the right half position, that is, the hill hold control position.

The port 194 is connected to the oil passage 3 by the oil passage 318.
20 and is supplied with the signal oil pressure Ps of the oil passage 320. The port 196 is supplied with throttle oil pressure or servo oil pressure (engagement pressure) for the clutch C1 through an oil passage (not shown).

The solenoid valve 240 operates according to the duty ratio D of the pulse signal applied to the electromagnetic coil.
A signal pressure Ps corresponding to the duty ratio D is generated in the oil passage 320. The solenoid valve 240 is constituted by a so-called normally-closed solenoid valve.
Decreases as the duty ratio D applied to the electromagnetic coil increases.

The oil passage 320 passes through the throttle 280, the oil passage 322, the modulator valve 250, and the oil passage 324, and
, Whereby the oil pressure 322 regulated to a predetermined constant pressure by the modulator valve 250 is supplied to the oil passage 322.

The oil passage 320 is connected to the oil passage 318 by B1.
It is connected to the port 194 of the control valve 180 and is also connected to the port 210 of the C1 control valve 200 via the oil passage 326 and the throttle 282.

The C1 control valve 200 has a spool 202 and two plugs 204 and 206.
Spool 202 is connected to oil passage 3 by oil passages 328 and 314.
00 and a port 21 to which the line pressure PL is supplied.
By controlling the degree of communication with the second drain port 216, the hydraulic pressure at the outlet port 214 is adjusted.

The pressure adjustment value increases in accordance with the urging force applied to the spool 202 by the compression coil spring 218 and the pressing force applied directly to the spool 202 by the plugs 204 and 206. Exit port 21
Reference numeral 4 is connected to the clutch C1 via the throttle 284 and the oil passage 330.

The oil passages 328 and 330 are connected to the oil passage 31
4. Connected by a check valve 260. The check valve 260 is configured to allow only the flow of the oil from the oil passage 330 to the oil passage 328, that is, the drain flow of the oil.

Next, the operation will be described.

When the manual shift range is set to the D range and the first speed is established, the spool 132 of the 1-2 shift valve 130 is at the lowered position,
The spool 142 of the 2-3 shift valve 140 is in the raised position.

The creep reduction control and the hill hold control have not been started yet, and the solenoid valve 240 is turned off.
While the F signal is given, the signal oil pressure P
s is set to the same oil pressure as the output oil pressure Pm of the modulator valve 250, and this oil pressure is set to the B1 control valve 18
0 port 194 and port 210 of the C1 control valve 200.

Accordingly, at this time, the spool 180 of the B1 control valve 180 is located at the left position, that is, the hill hold control start position, whereby the port 186 is closed and the port 188 is connected to the drain port 187.

When the port 190 communicates with the port 192, the line pressure PL from the oil passages 300 and 314 is increased.
Enters the port 208 of the C1 control valve 200 through the oil passage 316, and the C1 control valve 2
00 is located at the left position, that is, the normal mode position, by the action of the line pressure PL supplied to the port 208 in addition to the signal oil pressure Ps applied to the port 210.

As a result, since the drain port 216 is completely closed, the line pressure PL applied to the port 212 is not reduced, but is directly introduced into the clutch C1 from the port 214 via the oil passage 330.

Therefore, at this time, the clutch C1 is completely engaged, and the first speed is achieved. Further, since the port 186 of the B1 control valve 180 is closed, the port 188 is drain-connected, and the port 136 of the 1-2 shift valve 130 is also closed, and the port 138 is drain-connected. Is not supplied, and the brake B1 maintains the released state.

When the manual shift range is set to the D range, the throttle opening of the engine 1 is returned to the idle opening position (idle contact O
N) When the vehicle speed falls below a predetermined value close to zero, a predetermined signal is given to the solenoid valve 240 in order to perform creep reduction control and hill hold control, and the duty ratio D increases with time. Done.

As the duty ratio D increases, the oil passage 3
The signal pressure Ps at 20 gradually decreases over time,
When the signal oil pressure Ps decreases to a predetermined value Psset, B
1 The spool 182 of the control valve 180 switches to the right position in the figure, and the communication port of the port 188 switches from the drain port 187 to the port 186. Also, the communication port of the port 192 is changed from the port 190 to the drain port 1.
Switch to 98.

Accordingly, since the line pressure PL is not supplied to the port 208, the pressure adjustment value of the C1 control valve 200, that is, the engagement pressure of the clutch C1 is set by the signal oil pressure Ps applied to the port 210, and the signal oil pressure Ps The drain port 216 is opened with the decrease.

As a result, the clutch C1
The clutch C1 is caused to slip. Thus, the automatic transmission is in the same state as in the neutral state, and the occurrence of creep is prevented at the same time as the idle vibration is reduced. That is, creep reduction control is executed.

On the other hand, at this time, since the ports 186 and 188 of the B1 control valve 180 are in communication with each other as described above, the spool 142 of the 2-3 shift valve 140 is in the raised position, that is, the first gear or the second gear. In the switching position to achieve the step, the manual shift valve 11
If the line pressure PL of the D range port 116 of 0 is
0, 302, port 146 of 2-3 shift valve 140
And 150, oil passage 306, B1 control valve 18
0 through ports 186 and 188, an oil passage 312, a check valve 170, and an oil passage 314.
It reaches port 136 at 0.

Therefore, at this time, the 1-2 shift valve 1
30 if the spool 132 is in the raised position,
Line, the line pressure PL at port 136 is at port 1
The brake gear 38 is supplied to the brake B1 through the oil passage 316 so that the brake B1 is engaged and the sun gear is fixed.
Therefore, the rotation of each of the front sun gear and the rear sun gear is prevented, and the output shaft is prevented from rotating in the backward direction of the vehicle by the action of the one-way clutch F2, so that a so-called hill hold control is executed.

[0052]

When the pressure Ps regulated by the linear solenoid valve 240 falls below a normal value by means of the solenoid valve or the stick of the modulator valve, the B1 control valve 180 is turned off. By reducing the pressure introduced into the port 194, the B1 control valve 180 is held on the side where the brake B1 is engaged (the left half position in FIG. 8). That is, if the shift to the second speed in the D range is performed in this state, the D shift from the port 150 of the 2-3 shift valve 140 is performed.
The range line pressure PL passes through the oil passage 306, the ports 186, 188 of the B1 control valve 180, and further passes through the check valve 170, the oil passage 314, and the ports 136, 138 of the 1-2 shift valve 130, and the brake B
In this case, the brake B1 for the engine brake, which should not be engaged in the D range, is instantaneously engaged.

As a result, in the D range state, when the upshift from the first gear to the second gear is performed, the one-way clutch F2 which is the reaction element of the first gear shifts to the reaction element of the second gear. The "clutch-to-clutch" switching to the one-way clutch F1 can be controlled at a predetermined timing. Although the brake B1 should not be engaged, the engine is instantly output when the second speed signal is output. The brake B1 for braking is engaged, and the original smooth shifting is not performed. As a result, the torque drop due to the engagement of the brake B1 becomes large,
In addition, since the shift time is instantaneous, there is a problem that a strong shift shock occurs.

Similarly, at the time of manual shift from the D range to the S range (= 2 range), the operating pressure to the brake B1 is not the second coast modulator pressure lower than the line pressure, but the line pressure, so that the shift shock is generated. It will be great.

The present invention has been made in view of such a problem, and it is possible to guarantee the same shifting performance with less shock as in the normal state even when the modulator valve or the linear solenoid valve fails. By providing a hydraulic control device for an automatic transmission for a vehicle,
It is an object to solve the above problems.

[0056]

According to the present invention, as shown in FIG. 1, even when the shift range of the automatic transmission is set to the forward traveling range, when a predetermined condition is satisfied, a forward clutch is provided. By releasing C1 through the clutch control valve (C1 control valve) 200, a neutral state is formed to prevent the occurrence of creep, and at the same time, the brake control valve (B1
The clutch control valve 200 and the brake control valve 180 are provided in a hydraulic control system for an automatic transmission for a vehicle in which a brake B1 for forming an engine brake at a predetermined speed is engaged through a control valve 180 to prevent the vehicle from moving backward. And a second control means for controlling the brake control valve 180 in a system separate from the first control means, thereby solving the above-mentioned problem. is there.

[0057]

In the hydraulic control device according to the present invention, two means for controlling the brake control valve 180 are provided in separate systems. Therefore, for example, even if the first control means fails, the brake can be reliably held at the non-engagement position by the second control means different from the first control means.

[0058]

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

In the following, only the portions different from the above-mentioned prior art will be described, and the same portions will be denoted by the same reference numerals and description thereof will be omitted.

FIG. 2 is a circuit diagram of a hydraulic control device for an automatic transmission according to a first embodiment of the present invention, and FIG. 3 is a circuit diagram of a main part thereof.

In the apparatus of the first embodiment, a C1 relay valve 270 is arranged in the middle of an oil passage 330 that connects the port 214 of the C1 control valve 200 and the clutch C1. Then, C1 control valve 2
The port 214 of port 00 and the port 272 of the C1 relay valve 270 are connected by the oil passage 330.

The clutch C1 and the C1 relay valve 27
0 port 276 is connected by an oil passage 340. Further, the port 274 of the C1 relay valve 270 is connected to the D
The D range line pressure PL generated at the range port 116 is guided.

Further, an ON-OFF solenoid valve 400 is newly provided. This ON-OFF solenoid valve 400 is operated by ON / OFF operation,
The oil pressure of the oil passage 410 is controlled to a high pressure or a low pressure (drain). The oil passage 410 is connected via a throttle 411 and an oil passage 412 to an oil passage 126 that is adjusted to the line pressure PL by the primary regulator valve 124.

The C1 relay valve 270 has two control signal input (pilot) ports 277 and 278 for switching control of its own spool position in the same direction, and at least one of the ports 277 and 278. When a hydraulic pressure higher than the set pressure is introduced into 278, it is located at the right half position in FIG. 2, thereby connecting port 276 to 274. Also, when the pressures of both ports 277 and 278 are both lower than the set pressure, the port is located at the left half position in FIG.

The one control signal input port 277
Is connected to an oil passage 320 through an oil passage 334, and a pressure Ps for controlling a C1 control valve, which is adjusted by a linear solenoid valve 240, is introduced into a port 277.

The other control signal input port 278
Is connected to an oil passage 410 via an oil passage 413, and a hydraulic pressure controlled by an ON-OFF solenoid valve 400 is introduced into a port 278.

The port 196 for inputting the control signal of the B1 control valve 180 is not a means for generating a throttle pressure, but is connected to an oil passage 410 which is pressure-controlled by a newly provided ON-OFF solenoid valve 400. 414 are connected.

Here, the linear solenoid valve 24
0, the oil passage 320, the oil passage 318, and the oil passage 326 are connected to the C1 control valve 220 and the B1 control valve 180.
And ON-OF.
F solenoid valve 400, oil passage 410, oil passage 414
Corresponds to the second control means for controlling the B1 control valve 180.

Next, the operation of the hydraulic control device having the above configuration will be described.

In the apparatus of this embodiment, the B1 control valve 180 and the C1 control valve 200 function normally, and the linear solenoid valve 240
When the pressure and the modulator valve 250 function normally and the pressure Ps maintains the normal value, the same function as described above is performed.

On the other hand, when the pressure Ps regulated by the linear solenoid valve 240 falls below a normal value with a stick of the solenoid valve or the modulator valve or the like, the pressure introduced into the port 194 of the B1 control valve 180 remains unchanged. Is reduced, the B1 control valve 180 is held on the side where the brake B1 is engaged (the left half position in FIG. 2). That is, if the first speed or the second speed of the D range is set in that state,
2-3 The line pressure PL of the D range from the port 150 of the shift valve 140 passes through the oil passage 306, the ports 186 and 188 of the B1 control valve 180, and further passes through the check valve 170 and the oil passage 314 to 1-2. It will reach the port 136 of the shift valve 130.

Therefore, in this state, the 1-2 shift valve 1
When the gear 30 is shifted to the second gear position (left half position in FIG. 2), the line pressure PL reaching the port 136 is instantaneously introduced into the brake B1 via the port 138, and the original D
The brake B1 for the engine brake, which should not be engaged in the range, is instantaneously engaged. As a result, as described above, at the time of the upshift from the first speed to the second speed in the D range, there occurs a problem that a strong shift shock occurs due to the engagement of the brake B1.

However, in this hydraulic control apparatus, even if the pressure Ps takes an abnormal value, the high pressure hydraulic pressure can be applied to the control port 196 of the B1 control valve 180 by the ON-OFF solenoid valve 400. Before the above situation occurs, the B1 control valve 180 can be held at the switching position on the brake B1 non-engagement side. Therefore, a smooth shifting operation can be guaranteed as in the normal case.

In addition, the present hydraulic control device has the following fail-safe function.

That is, when one or both of the B1 control valve 180 and the C1 control valve 200 fail, as long as the output pressure Ps of the linear solenoid valve 240 rises to a predetermined value or more, the ports 274 to 276 of the C1 relay valve are used. Since the line pressure PL from the D range port 116 of the manual valve 110 is guided to the clutch C1 through the oil passage 340, the vehicle can run forward.

Further, the newly added C1 relay valve 2
When the port 70 itself sticks, for example, in a state where the ports 272 and 276 are in communication with each other, as long as the C1 control valve 200 (and the B1 control valve 180) is operating normally, the D range line pressure is applied to the oil passage 330. Since the vehicle is guided, the vehicle can travel forward without any trouble.

The port 27 of the C1 relay valve 270
Even if the sticks 6 and 274 are stuck in a communicating state, the creep reduction control by the C1 control valve 200 becomes impossible, but the vehicle can travel forward.

If the linear solenoid valve 240 or the modulator valve 250 fails and the pressure Ps falls below the normal value, the C1 relay valve 2 is not affected.
2 is located at the left half position in FIG. 2, the communication state of the ports 274 and 276 cannot be maintained, the engagement pressure of the clutch C1 decreases, and the vehicle cannot travel forward.

However, before such a state is reached, after the foot brake is determined to be OFF, O
Activate the N-OFF solenoid valve 400 and set the oil passage 4
The hydraulic pressure of 10 is increased. As a result, the line pressure PL is applied to another control port 278 of the C1 relay valve 270.
Is introduced, and the C1 relay valve 270 is in the state of the right half of FIG. As a result, the line pressure PL in the D range is supplied to the clutch C1 via the ports 274 and 276,
The clutch C1 is completely engaged and the vehicle can run forward.

Next, a second embodiment of the present invention will be described.

FIG. 4 is a circuit diagram of a hydraulic control device for an automatic transmission according to a second embodiment of the present invention, and FIG. 5 is a circuit diagram of a main part thereof. In the device of the second embodiment, a C1 drain control valve 570 is disposed in the middle of an oil passage 338 that connects the drain port 216 of the C1 control valve 200 and the drain tank 279.

Then, the C1 control valve 200
The drain port 216 and the port 576 of the C1 drain control valve 570 are connected by an oil passage 338. The port 572 of the C1 drain control valve 570 and the drain tank 279 are connected by an oil passage 340. Further, a D range line pressure PL generated at the D range port 116 of the manual valve 110 is guided to a port 574 of the C1 drain control valve by an oil passage 336.

Also, in this embodiment, the ON-OFF solenoid valve 400 is provided just like the first embodiment, and the port 196 for inputting the control signal of the B1 control valve 180 is connected to the ON-OFF solenoid valve 400.
Is connected via an oil passage 414 to an oil passage 410 whose pressure is controlled by the oil passage.

The drain control valve 570 has two control signal input (pilot) ports 577, 578 for switching control of its own spool position in the same direction, and at least one of the ports 577, 578.
When a hydraulic pressure higher than the set pressure is introduced to the port 578, the port 578 is located at the right half position in FIG.
6 to 574. Also, both ports 577, 5
When both pressures at 78 are lower than the set pressure, it is located in the left half position of FIG.
The port 572 communicating with the drain tank 279 communicates with the port.

The one port 577 is connected to the oil passage 320 via an oil passage 332, and the pressure Ps for controlling the C1 control valve, which is adjusted by the linear solenoid valve 240, is introduced into the port 577. ing.

The other port 578 is connected to the oil passage 410 via the oil passage 413, and the port 578 is
The hydraulic pressure controlled by the OFF solenoid valve 400 is introduced.

Here, the linear solenoid valve 24
0, the oil passage 320, and the oil passage 332 correspond to first control means for controlling both the drain control valve 570 and the B1 control valve 180, and the ON-OFF solenoid valve 400, the oil passage 410, and the oil passage 414 B1 corresponds to a second control means for controlling the switching of the control valve 180.

Next, the operation of the hydraulic control device according to the second embodiment will be described.

Also in the hydraulic apparatus of this embodiment, when the pressure Ps regulated by the linear solenoid valve 240 falls below a normal value by the stick of the solenoid valve or the modulator valve, the first embodiment is different from the first embodiment. It functions in exactly the same way to eliminate shifting shocks.

The hydraulic control apparatus further has the following fail-safe function.

That is, regardless of the state in which one or both of the B1 control valve 180 and the C1 control valve 200 fails, as long as the output pressure Ps of the linear solenoid valve 240 increases to a predetermined value or more, the C1 drain control valve 570 port 57
Since the line pressure PL from the D range port 116 of the manual valve 110 is led to 6, the pressure-reducing function of the C1 control valve 200 is pushed out and the forward pressure can be reduced because the engagement pressure of the clutch C1 is not reduced. Become like

Further, the newly added C1 drain control valve 570 itself is connected to the ports 572 and 576, for example.
When the stick sticks in the communication state, the C1 control valve 200 (and the B1 control valve 1
As long as 80) operates normally, the D range line pressure is guided to the oil passage 330, so that the vehicle can travel forward without any trouble.

The C1 drain control valve 570
In this case, the creep reduction control by the C1 control valve 200 becomes impossible, but the vehicle can run forward even if the ports 576 and 574 are stuck in communication.

If the linear solenoid valve 240 or the modulator valve 250 fails and the pressure Ps drops below the normal value, the drain Pv drops as shown in FIG. As a result, the communication state of the ports 574 and 576 cannot be maintained, the engagement pressure of the clutch C1 decreases, and the vehicle cannot travel forward.

However, before such a state is reached, after the foot brake is determined to be OFF, O is set for a predetermined time (short time).
Activate the N-OFF solenoid valve 400 and set the oil passage 4
The hydraulic pressure in 10 is increased.

As a result, the drain control valve 5
The line pressure PL is introduced into another control port 578 of 70, and the drain control valve 570 is in the state of the right half of FIG. As a result, the manual valve 1 is connected to the drain port 516 of the C1 drain control valve 570.
Since the line pressure PL is guided from the D range port 116 of FIG. 10, the pressure reducing function of the C1 control valve 200 is suppressed and the engagement pressure of the clutch C1 is not reduced, so that the vehicle can travel forward. .

In the above-described embodiment, the linear solenoid valve 240 has a characteristic that the output pressure Ps decreases as the duty ratio increases. However, the linear solenoid valve 240 increases the duty ratio. At the same time, the output pressure Ps may have a characteristic that increases. In this case, the control pressure Ps may be introduced to the clutch control valve from the opposite direction.

[0098]

As described above, according to the present invention, in an automatic transmission that performs hill hold control simultaneously with creep reduction control, a separate system is used as switching control means of a brake control valve for executing the hill hold control. Therefore, even if a failure occurs in one system, the brake can be reliably held at the non-engagement position in the other system. Therefore, even in the event of an emergency, it is possible to guarantee a smooth shifting operation as in the normal case.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the gist of the present invention.

FIG. 2 is a hydraulic control circuit diagram showing a configuration of a device portion for performing basic creep reduction control and hill hold control in the first embodiment of the present invention.

FIG. 3 is a hydraulic control circuit diagram schematically showing functions of main parts of the circuit diagram of FIG. 2;

FIG. 4 is a hydraulic control circuit diagram showing a configuration of a device portion for executing basic creep reduction control and hill hold control in a second embodiment of the present invention.

FIG. 5 is a hydraulic control circuit diagram schematically showing functions of main parts of the circuit diagram of FIG. 4;

FIG. 6 is a skeleton diagram showing a transmission section of the vehicular automatic transmission in question here.

FIG. 7 is a diagram showing engagement and disengagement states of a friction engagement device at each shift speed in the automatic transmission.

FIG. 8 is a hydraulic control circuit diagram showing a configuration of a device portion for executing conventional basic creep reduction control and hill hold control.

FIG. 9 is a hydraulic control circuit diagram schematically showing functions of main parts of the circuit diagram of FIG. 8;

[Explanation of symbols]

C1 ... clutch (forward clutch), B1 ... brake (brake to be engaged during hill hold control), 110 ... manual valve, 180 ... B1 control valve, 200 ... C1 control valve, 240 ... linear solenoid valve (first control means) 400) ON-OFF solenoid valve (main element of the second control means).

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-180148 (JP, A) JP-A-59-180147 (JP, A) JP-A-59-180145 (JP, A) JP-A 61-180145 88055 (JP, A) JP-A-1-229147 (JP, A) JP-A-2-42270 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) F16H 59/00-61 / 12,61 / 16-61/2 4,63 / 40-63/48 B60K 41/00-41/28

Claims (1)

(57) [Claims] A neutral state is established by releasing a forward clutch through a clutch control valve when a predetermined condition is satisfied, even when the shift range of the automatic transmission is set to a forward travel range. A hydraulic control device for an automatic transmission for a vehicle for preventing the occurrence of creep and simultaneously engaging a brake for forming an engine brake at a predetermined gear through a brake control valve to prevent the vehicle from moving backward. A first control unit that controls both the control valve and the brake control valve; and a second control unit that controls the brake control valve in a system different from the first control unit. Hydraulic control device for automatic transmission for vehicles.