JPH05322013A - Oil pressure controller for automatic transmission - Google Patents

Abstract

PURPOSE:To reduce shift operation guarantee oil pressure so as to prevent enlargement of a solenoid valve and rise in cost in the case of using high line pressure. CONSTITUTION:An oil pressure controller for an automatic transmission is provided with a line pressure regulator valve 200, a solenoid valve S2 which receives line pressure as supply pressure and responses to a shift control signal so as to operate and output controlled oil pressure, and a reverse inhibit valve 203 which is shift controlled by control oil pressure output by the solenoid valve S2 and inhibits attainment to a reverse stage. And the unit is constituted to provide reverse inhibit control when the judgment is made that it is in a situation to inhibit the attainment to the reverse stage, to reduce the line pressure prior to the output of the shift control signal to the solenoid valve S2, to output the shift control signal to the solenoid valve S2 as it is so as to shift the solenoid valve S2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic vehicle for a vehicle in which a solenoid valve outputs a control hydraulic pressure in response to a line pressure supply and the reverse hydraulic inhibit valve is switched by the control hydraulic pressure to prohibit the achievement of a reverse gear. The present invention relates to a hydraulic control device for a transmission.

[0002]

2. Description of the Related Art As an example of this type of hydraulic control device, the one described in Japanese Patent Application Laid-Open No. 2-80852 is known.

This hydraulic control device includes means for controlling the line pressure according to the engine output, and a solenoid valve that outputs the control hydraulic pressure by operating in response to a receiving switching control signal with the line pressure as the supply pressure. And a reverse inhibit valve that is switched and controlled by the control hydraulic pressure output from the solenoid valve to prohibit the achievement of the reverse gear. By controlling the solenoid valve, the reverse inhibit valve is controlled.

[0004]

By the way, in recent years, there has been a tendency to adopt a high line pressure due to an increase in engine output or a reduction in the number of friction materials of a friction engagement device accompanying the downsizing of an automatic transmission. There is. As a result, there is a problem that the solenoid valve becomes large in size due to the increase in the hydraulic pressure for guaranteeing the switching operation of the solenoid valve, which in turn causes an increase in cost.

The present invention has been made in view of such a conventional problem, and it is possible to reduce the switching operation guarantee hydraulic pressure of the solenoid valve for controlling the reverse inhibit valve even when a high line pressure is used. By providing a hydraulic control device for an automatic transmission that can prevent increase in size and cost of the solenoid valve,
This is a solution to the above problems.

[0006]

As shown in FIG. 1, the present invention has means for controlling the line pressure in accordance with the output of the engine, and receiving switching control using the line pressure as the supply pressure. With a solenoid valve that outputs control hydraulic pressure with
A hydraulic control device for an automatic transmission, comprising: a reverse inhibit valve that is switch-controlled by a control hydraulic pressure output from the solenoid valve to prohibit achievement of a reverse gear,
The reverse stage prohibition judging means for judging whether or not the state in which the achievement of the reverse gear is prohibited has occurred, and the reverse stage prohibition prohibiting means judges that the state in which the achievement of the reverse gear is prohibited has occurred, Prior to the switching control of the solenoid valve, a line pressure reducing means for reducing the line pressure, and a switching execution means for executing the switching control of the solenoid valve after the line pressure reduction control by the line pressure reducing means are provided. This solves the above problem.

[0007]

In general, in a solenoid valve, the load is larger when switching is performed against line pressure than when it is held at a fixed position. Therefore, if the line pressure is increased for the reasons described above, not only will the load for holding the fixed position increase, but
The load at the time of switching will be further increased. The present invention has been made in view of this point, and the maximum load can be reduced by reducing the line pressure during the switching operation, thereby enabling the use of a solenoid valve with a lower guaranteed hydraulic pressure. It is the one.

That is, in the hydraulic control system for an automatic transmission according to the present invention, when a state in which achievement of the reverse gear should be prohibited occurs, the reverse gear prohibition judging means judges it, and when this judgment is made, Prior to the switching control of the solenoid valve, the line pressure reducing means reduces the line pressure, and in that state, the switching execution means executes the switching control of the solenoid valve.

The solenoid valve outputs a control hydraulic pressure according to the switching control by the switching execution means, and supplies the control hydraulic pressure to a reverse inhibit valve (a valve that prohibits the achievement of the reverse gear). The reverse inhibit valve performs a switching operation in response to the control oil pressure, and the operation inhibits the achievement of the reverse gear.

[0010]

Embodiments of the present invention will now be described in detail with reference to the drawings.

First, a concrete example of an automatic transmission system for a vehicle to which the present invention is applied will be described with reference to FIGS.

The automatic transmission system shown in FIG. 2 has an engine (E / G) 1, an automatic transmission (A / T) 2, and an engine (E).
/ G) control computer 10, automatic transmission hydraulic control device 20, automatic transmission (A / T) control computer 30, and various sensor groups 40. The E / G control computer 10 and the A / T control computer 30 respectively control the engine 1 and the automatic transmission 2 based on the input data from the various sensor groups 40.

An intake pipe 3 of the engine 1 is provided with a main throttle valve 4 and a sub-throttle valve 5, the main throttle valve 4 is controlled in opening degree in conjunction with an accelerator pedal 6, and the sub-throttle valve 5 is an actuator (motor). ) 7
The opening degree is controlled by.

Further, the engine 1 is provided with a mechanism 8 for adjusting the fuel injection amount and a mechanism 9 for adjusting the ignition timing, and the E / G control computer 10 controls the sub-throttle valve 5 and the fuel injection. By controlling the quantity control mechanism 8 and the ignition timing control mechanism 9, for example, the engine output is adjusted by a known method.

FIG. 3 shows a skeleton of the automatic transmission 2. The automatic transmission 2 includes a torque converter 111, a sub transmission unit 112, and a main transmission unit 113.

The torque converter 111 has a lockup clutch 124. The lockup clutch 124 is provided between a front cover 127 that is integrated with the pump impeller 126 and a member (hub) 129 to which a turbine runner 128 is integrally attached.

The crankshaft (not shown) of the engine 1 is connected to the front cover 127. The input shaft 130 connected to the turbine runner 128 includes an overdrive planetary gear mechanism 13 that constitutes the auxiliary transmission unit 112.
It is connected to one carrier 132.

A clutch C0 and a one-way clutch F0 are provided between the carrier 132 and the sun gear 133 in the planetary gear mechanism 131. The one-way clutch F0 is adapted to be engaged when the sun gear 133 rotates forward relative to the carrier 132 (rotates in the rotational direction of the input shaft 130).

On the other hand, a brake B0 for selectively stopping the rotation of the sun gear 133 is provided. Further, a ring gear 134 which is an output element of the auxiliary transmission section 112 is connected to an intermediate shaft 135 which is an input element of the main transmission section 113.

The sub-transmission unit 112 has the planetary gear mechanism 1 when the clutch C0 or the one-way clutch F0 is engaged.
Since the whole 31 rotates integrally, the intermediate shaft 135
Rotates at the same speed as the input shaft 130. Further, in the state where the brake B0 is engaged and the rotation of the sun gear 133 is stopped, the ring gear 134 is accelerated with respect to the input shaft 130 to rotate normally. That is, the subtransmission unit 112 can set switching between high and low.

The main transmission unit 113 has three sets of planetary gear mechanisms 140, 150, 160, and these gear mechanisms 140, 150, 160 are connected as follows.

That is, the sun gear 141 of the first planetary gear mechanism 140 and the sun gear 151 of the second planetary gear mechanism 150 are integrally connected to each other, and the ring gear 143 of the first planetary gear mechanism 140 and the second planetary gear mechanism 150 are connected. Carrier 1
52 and the carrier 162 of the third planetary gear mechanism 160 are connected together. Further, the output shaft 170 is connected to the carrier 162 of the third planetary gear mechanism 160. Further, the ring gear 153 of the second planetary gear mechanism 150 is connected to the sun gear 161 of the third planetary gear mechanism 160.

The gear train of the main transmission unit 113 can set one reverse gear and four forward gears, and clutches and brakes therefor are provided as follows.

That is, the ring gear 153 of the second planetary gear mechanism 150 and the sun gear 161 of the third planetary gear mechanism 160.
A clutch C1 is provided between the intermediate shaft 135 and the intermediate shaft 135, and a clutch C2 is provided between the sun gear 141 of the first planetary gear mechanism 140 and the sun gear 151 of the second planetary gear mechanism 150 and the intermediate shaft 135.

A brake B1 for stopping the rotation of the sun gears 141 and 151 of the first planetary gear mechanism 140 and the second planetary gear mechanism 150 is arranged. Also, these sun gear 1
A one-way clutch F1 and a brake B2 are arranged in series between 41 and 151 and the casing 171.
The one-way clutch F1 is adapted to be engaged when the sun gears 141 and 151 try to rotate in the reverse direction (rotation in the direction opposite to the rotation direction of the input shaft 135).

The carrier 142 of the first planetary gear mechanism 140
A brake B3 is provided between the casing and the casing 171. In addition, the ring gear 16 of the third planetary gear mechanism 160
A brake B4 and a one-way clutch F2 as elements for stopping the rotation of No. 3 are arranged in parallel with each other between the casing 171. The one-way clutch F2 is adapted to be engaged when the ring gear 163 tries to rotate in the reverse direction.

In the automatic transmission 2 described above, the entire reverse speed is set to 1 speed and the forward speed is set to 5 speeds.

FIG. 4 shows an engagement operation table of each clutch and brake (friction engagement device) for setting the five shift speeds.
Shown in. In FIG. 4, a circle indicates an engaged state, a circle indicates an engaged state during engine braking, and a blank indicates a released state.

Each clutch and brake (friction engagement device)
The solenoid valves S1, S2, S3, S4, SLN, SLT, S in the hydraulic control device 20 are engaged or released.
The LU is executed by being drive-controlled based on a command from the computer 30.

Here, S1, S2 and S3 are shift solenoid valves, S4 is an engine brake actuation solenoid valve, SLN is an accumulator back pressure control solenoid valve, SLT is a line pressure control solenoid valve, and SLU is a lock. The solenoid valve for up is shown.

The A / T control computer 30 includes signals from various sensor groups 40, for example, the vehicle speed sensor 4
1, a vehicle speed signal (output shaft rotational speed N0 signal), a throttle opening signal (accelerator opening signal) from the throttle sensor 42, and a pattern select signal from the pattern select switch 43 (driving with emphasis on power selected by the driver, Selection signal for fuel efficiency-oriented driving, etc., shift position signal from shift position switch 44, brake switch 4
In addition to basic signals such as the foot brake signal from 5, C
The rotational speed signal of the clutch C0 from the 0 sensor 46 is input.

FIG. 5 shows a reverse inhibit valve 20.
3 shows the outline of a circuit for prohibiting the achievement of the reverse gear by controlling the switching of No. 3. That is, this circuit controls the reverse inhibit valve 203 to be switched by operating the solenoid valve S2 when the vehicle speed is equal to or higher than the predetermined slight speed, whereby the R range line pressure from the manual valve 205 for achieving the reverse speed is achieved. The frictional engagement device brake B4 and the clutch C2 are prevented from being supplied.

In this circuit, the line pressure control valve (primary regulator valve) 200 is supplied with oil pressure from an oil pump and is also supplied with control oil pressure from a linear solenoid valve SLT. Normally, this control oil pressure corresponds to the throttle opening (engine output), and takes a value that raises the line pressure at high throttle opening. The linear solenoid valve SLT may be either a type (normally open type) in which the control hydraulic pressure becomes high or a type (normally closed type) in which the control hydraulic pressure becomes low according to the input current value. In this example, the former type is used.

By changing the input current value to the linear solenoid valve SLT, the control oil pressure changes, and by changing the control oil pressure, the line pressure control valve 200 is controlled and the line pressure output thereby changes. The line pressure output from the line pressure control valve 200 is the source pressure for all of the hydraulic control device, and is the supply pressure to the shift solenoid valves S1, S2, S3, S4.

Here, the solenoid valve S2 has a role of switching a shift valve (not shown), and also has a role of switching the reverse inhibit valve 203.
The reverse inhibit valve 203 is supplied with hydraulic pressure via the manual valve 205 during the R range. The reverse inhibit valve 203 has a role of prohibiting the achievement of the reverse gear when the vehicle is shifted from D to R at a high vehicle speed.

The solenoid valve S2 receives the supply of the line pressure produced by the line pressure control valve 200 and outputs a control oil pressure according to the input current value (switch control signal). This control oil pressure is input as the control oil pressure of the reverse inhibit 203, and the reverse inhibit valve 203 is switch-controlled in accordance with the control oil pressure to block the inflow of the R range line pressure into the friction engagement device 204. Since this hydraulic circuit itself is already widely known, further description will be omitted.

Although a 2-way valve is used as the solenoid valve S2 in the illustrated example, a 3-way valve may be used.

Next, the A / T control computer 3
An example of the control executed by 0 will be described with reference to the flowchart of FIG.

In this control example, when the processing is started, the input signal processing is performed in the first step 502, and it is determined in the next step 504 whether the throttle opening is equal to or more than a predetermined value α. The reason for making this determination is that the line pressure becomes particularly large when this condition is satisfied, and in this control example, the line pressure reduction control to be described later is to be executed only when the line pressure becomes particularly large. Because. This is based on the idea that the line pressure should not be unnecessarily reduced when it is considered that no particular problem occurs. If this determination is NO, the process proceeds to the return step.

If the determination in step 504 is YES, it is determined in step 506 whether the vehicle speed is equal to or higher than the predetermined value V1. When the vehicle speed is lower than the predetermined value V1, the reverse inhibit control is not performed, so the process proceeds to the return step.

If the determination in step 506 is YES, the process proceeds to step 508 to determine whether the line pressure reduction control is possible. Specifically, it is determined whether or not the linear solenoid valve SLT that controls the line pressure control valve 200 has failed. If this line pressure reduction control is not possible, the R range shift warning lamp is turned on in step 514 to warn the driver not to cause reverse inhibit control. However, even in this state, when the reverse inhibit condition is satisfied, the reverse inhibit control is prioritized and the reverse inhibit control is performed (steps 516 and 51).
8).

If the line pressure reduction control is possible, the determination at step 508 is YES and the routine proceeds to step 510, where it is determined whether the shift range is the N range.
In the case of the N range, the routine proceeds to step 512, where the line pressure reduction control is executed, and the routine proceeds to the return step.

The line pressure is thus reduced in advance from the N range stage. The reason is that there is a response delay and dead time, and therefore it may not be sufficient to reduce the line pressure after detecting the R range.

If it is not in the N range, the determination in step 510 becomes NO and the process proceeds to step 520, where it is determined whether or not it is in the R range. Step 52 for R range
Go to 2 and execute (or continue) the line pressure reduction control
Then, in that state, the reverse inhibit control is executed in step 524, and the process proceeds to the return step. The line pressure is restored at an appropriate time after the switching of the solenoid valve is completed. If it is neither the N range nor the R range, the process proceeds to the return step through steps 510 and 520.

As described above, according to this embodiment, the line pressure is reduced prior to the switching of the solenoid valve for performing the reverse inhibit control, and the switching of the solenoid valve is executed in that state, so that the solenoid The load during the switching operation of the valve is reduced, which makes it possible to use a solenoid valve having a low switching operation guarantee hydraulic pressure, a lighter weight, and a lower cost.

[0046]

As described above, according to the hydraulic control system for an automatic transmission of the present invention, since the line pressure during the switching operation of the solenoid valve is reduced, the use of the solenoid valve having a low switching operation guarantee hydraulic pressure is possible. Is possible. Therefore, the solenoid valve can be downsized and the cost can be reduced.

[Brief description of drawings]

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

FIG. 2 is a schematic block diagram of a vehicle automatic transmission system to which the present invention is applied.

FIG. 3 is a block diagram showing an outline of an automatic transmission in the automatic transmission system.

FIG. 4 is a view showing an engagement state of each friction engagement device in the automatic transmission.

FIG. 5 is a diagram showing an example of a hydraulic circuit of a friction engagement device in the automatic transmission.

FIG. 6 is a flowchart showing a control flow executed in a computer for controlling the automatic transmission.

[Explanation of symbols]

200 ... Line pressure control valve (primary regulator valve) S2 ... Solenoid valve 203 ... Reverse inhibit valve B4, C2 ... Friction engagement device in which hydraulic pressure is cut during reverse inhibit control

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masahiko Ando 10 Takane, Fujii-cho, Anjo City, Aichi Prefecture Aisin AW Co., Ltd. (72) Inventor Akira Fukatsu 10 Takane, Fujii-cho, Anjo City, Aichi Prefecture Aisin・ AW Co., Ltd.

Claims (1)

[Claims] 1. A means for controlling a line pressure according to an output of an engine, a solenoid valve for outputting a control hydraulic pressure by receiving and controlling the line pressure as a supply pressure, and a control hydraulic pressure output by the solenoid valve. Reverse control prohibition judgment that determines whether or not a condition that should prohibit the achievement of reverse gear has occurred in a hydraulic control device for an automatic transmission equipped with a reverse inhibit valve that is switch-controlled by And a line pressure reducing means for reducing the line pressure prior to switching control of the solenoid valve when the reverse speed prohibition prohibiting means determines that a state in which the achievement of the reverse speed should be prohibited has occurred. Switching control means for executing switching control of the solenoid valve after the line pressure reduction control by the pressure reduction means; Machine hydraulic control device.