JP2914039B2 - Vehicle hydraulic control unit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a front / rear wheel drive torque distribution control system for finely controlling the torque distribution between front and rear wheels in accordance with the magnitude of clutch engagement force due to control pressure supplied to a hydraulic multi-plate friction clutch. The present invention relates to a vehicle hydraulic control unit applied to a vehicle.

[0002]

2. Description of the Related Art Conventionally, a proportional electromagnetic pressure reducing valve used in a vehicle hydraulic control unit has a spool and a proportional solenoid, and controls a supply pressure port to control a solenoid force generated in proportion to a current value to the proportional solenoid. It is generally known that a pressure supplied from an oil pump is made a control pressure corresponding to a solenoid current value by applying pressure to a spool in a direction in which a pressure port communicates with the spool.

[0003]

However, in the above-described conventional proportional electromagnetic pressure reducing valve, if the current value to the proportional solenoid is reduced to zero at the time of a system failure, the solenoid force on the spool disappears, and the spool force is reduced by the spring force of the return spring. Is fixed at the position that connects the control pressure port and the drain port, the control system to which the hydraulic control unit using this proportional electromagnetic pressure reducing valve is applied is used to prevent sudden changes in vehicle behavior and ensure the significance of installing the system. If there is a request to keep a certain control pressure applied during a failure, the request cannot be met.

Accordingly, the present applicant has filed a Japanese Patent Application No. Hei.
In the specification and drawings of No. 08 (filed on May 19, 1992), an on / off solenoid and a fail-safe spring are added to the conventional proportional electromagnetic pressure reducing valve, and the on / off solenoid is de-energized in the event of a failure due to a sensor failure or disconnection. A proportional electromagnetic pressure reducing valve with a fail-safe function that obtains a fail-safe pressure with a constant pressure by applying a spring force of a fail-safe spring to a spool has been proposed. When the on / off solenoid is energized in the normal state, the action of the spring force on the spool by the fail-safe spring is prevented by the solenoid force.

However, when the proportional electromagnetic pressure reducing valve with the fail-safe function is used, there are the following problems.

Immediately after the ignition is turned on, the on / off solenoid is energized, but the failsafe pressure acting on the hydraulic actuator at the time of non-energization drops at once. Immediately after the ignition is turned off, the on / off solenoid is de-energized. When the on-off solenoid is de-energized, a fail-safe pressure is generated at once and acts on the hydraulic actuator.

As a result, in a hydraulic actuator such as a multi-plate clutch, the oil pressure suddenly decreases / increases from zero to the fail-safe pressure, generating abnormal noise.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems. In a vehicle hydraulic control unit provided with a proportional electromagnetic pressure reducing valve having a proportional solenoid and an on / off solenoid, a difference in hydraulic actuator at the time of ignition on / off is provided. An object is to prevent generation of sound.

[0009]

In order to solve the above-mentioned problems, a hydraulic control unit for a vehicle according to the present invention is provided with an ignition-on solenoid control means and an ignition-off solenoid control means for controlling an on / off solenoid and a proportional solenoid in relation to each other. , Energizing the on / off solenoid
A means for suppressing a sudden decrease or increase in hydraulic pressure due to non-energization by controlling the proportional solenoid.

That is, as shown in the claim correspondence diagram of FIG. 1, a hydraulic pressure source a, a spool b, a proportional solenoid c and an on / off solenoid d are provided. The input pressure from the hydraulic pressure source a is used as a control pressure, and when a power is not supplied to the on / off solenoid d, a spring force is applied to the spool b by a fail-safe spring e. A proportional electromagnetic pressure reducing valve f for releasing the action of the spring force of the fail-safe spring e on the spool b, a hydraulic actuator g driven by oil pressure from the proportional electromagnetic pressure reducing valve f, and an ignition for detecting on / off of an ignition switch On / off detection means h, at the time of detection immediately after ignition is turned on An ignition-on solenoid control means i for applying a solenoid current for obtaining a nearly fail-safe pressure to the proportional solenoid c at the same time as energizing the on-off solenoid d, and a solenoid current for substantially obtaining a fail-safe pressure upon detection immediately after the ignition is turned off. Applied to the solenoid c and then on / off solenoid d
And an ignition-off solenoid control means j for turning off the power.

[0011]

When the ignition switch is turned on from off and the ignition on / off detection means h detects that the ignition has just been turned on, the on / off solenoid d of the proportional electromagnetic pressure reducing valve f is energized in the ignition on solenoid control means i. At the same time, a solenoid current for obtaining a nearly fail-safe pressure is applied to the proportional solenoid c.

Therefore, when the ignition is turned off, the on / off solenoid d of the proportional electromagnetic pressure reducing valve f is de-energized, so that the spring force of the fail safe spring e acts on the spool b to generate the fail safe pressure. However, the fail-safe pressure tends to drop at once due to the release of the spring force accompanying the energization of the on / off solenoid d. However, at the same time that the on / off solenoid d is energized, a solenoid current for obtaining a nearly fail-safe pressure is applied to the proportional solenoid c, so that the solenoid force acts on the spool b instead of the spring force. A sharp drop having a head drop in the hydraulic pressure output from the pressure reducing valve f to the hydraulic actuator g is suppressed.

When the ignition switch is turned off from on and the ignition on / off detecting means h detects that the ignition has just been turned off, the solenoid control means j at the time of ignition off supplies a solenoid current for obtaining a nearly fail-safe pressure to a proportional electromagnetic pressure reducing valve. f applied to a proportional solenoid c, then an on-off solenoid d
Is de-energized.

Therefore, when the ignition is turned on, the on / off solenoid d of the proportional electromagnetic pressure reducing valve f is energized.
It was zero pressure without the spring force by
The failsafe pressure is about to rise at once due to the action of the spring force accompanying the non-energization of the on / off solenoid d.
However, before the fail-safe pressure rises, the fail-safe pressure is almost obtained by applying the solenoid current to the proportional solenoid c of the proportional electromagnetic pressure reducing valve f. By performing the transfer of the hydraulic pressure to the fail-safe pressure that occurs, a sudden increase in the hydraulic pressure output from the proportional electromagnetic pressure reducing valve f to the hydraulic actuator g can be suppressed.

[0015]

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

First, the configuration will be described.

FIG. 2 is a diagram of a rear wheel drive base front and rear wheel drive torque distribution control system to which the vehicle hydraulic control unit of the embodiment of the present invention is applied.

In FIG. 2, 1 is an engine, 2 is a transmission, 3 is a rear propeller shaft, 4 is a rear differential, 5 and 6 are rear drive shafts,
7, 8 are rear wheels, 9 is a transfer, 10 is a front propeller shaft, 11 is a front differential, 1
2, 13 are front drive shafts, and 14, 15 are front wheels.

The transfer 9 has a built-in wet multi-plate clutch 16 (corresponding to a hydraulic actuator) whose drive torque is distributed to the front wheels 14 and 15 depending on the magnitude of the fastening force.

The wet-type multi-plate clutch 16 has a fastening force controlled by a control pressure generated by a hydraulic unit 18 by a control current from an ETS control unit 17. The ETS control unit 17 includes a right front wheel rotation sensor 19. , Left front wheel rotation sensor 20, right rear wheel rotation sensor 21, left rear wheel rotation sensor 22, lateral acceleration sensor 23
Sensor information from the user is input.

Basically, the control law is to increase the drive torque distribution to the front wheels in accordance with the occurrence of the difference between the front and rear wheel rotational speeds, and to ensure the optimum control regardless of the turning or the change of the road surface friction coefficient. The gain is reduced as the lateral acceleration increases.

FIG. 3 is a diagram showing the hydraulic unit 18 of the embodiment.

In FIG. 3, the hydraulic unit 18 comprises an electric motor 24, an oil pump 25, an accumulator 26
(Equivalent to a hydraulic pressure source), a proportional electromagnetic pressure reducing valve 27 with a fail-safe function, a pressure switch 28, a relief valve 29, a check valve 30, and an air bleeder 31. The reservoir tank 32 provided outside is the air bleeder. 31
And a suction pipe 33, and the proportional electromagnetic pressure reducing valve 27 and a return pipe 34. The proportional electromagnetic pressure reducing valve 27 with the fail-safe function and the piston oil chamber of the wet-type multi-plate clutch 16 are communicated by a control pressure pipe 35.

The electric motor 24 includes a pressure switch 28
ON-OFF control is performed by a command from the ETS control unit 17 based on the switch signal from the ETS.

FIG. 4 is a sectional view showing a proportional electromagnetic pressure reducing valve 27 with a fail-safe function used in the hydraulic unit 18 of the embodiment.

In FIG. 4, 36 is a spool, 37 is a housing, 38 is a feedback oil passage, 39 is a control pressure port, 40 is a supply pressure port, 41 is a drain port,
2 is a plate, 43 is a control solenoid coil (corresponding to a control solenoid), 44 is a control plunger, 45 is a case, 46 is an on-off solenoid coil (corresponding to an on-off solenoid), 47 is a fail-safe plunger, 48
Is a fail-safe spring, and 49 is a return spring.

When the system is normal, the control solenoid coil 43 reduces the accumulator pressure by the control current i ₁ from the ETS control unit 17 to control the accumulator pressure.

The on / off solenoid coil 46 operates the fail-safe spring 4 by a constant control current i ₂ (on) from the ETS control unit 17 in a normal state.
The spring force of No. 8 is prevented from acting on the spool 36, and a zero current (off) is applied to the spool force of the fail-safe spring 48 on the spool 36 during a failure. For details, refer to Japanese Patent Application No.
See the specification and drawings of No. 6408 (filed on May 19, 1992).

FIG. 5 is a block diagram of a solenoid control system when the ignition of the vehicle hydraulic control unit of the embodiment is turned on and off.

In FIG. 5, reference numeral 50 denotes an ignition switch, and an ETS control unit 17 includes an ignition on / off detection circuit 17a (corresponding to ignition on / off detection means) and an ignition on / off solenoid control circuit 17b (ignition on / off solenoid control means and Ignition-off-time solenoid control means).

Next, the operation will be described.

FIG. 6 shows the operation of the solenoid control process when the ignition is turned on and off.
Each step will be described below with reference to a flowchart showing the flow of the solenoid control processing operation when the ignition is turned on / off performed in step (1).

At step 60, it is determined from the switch signal from the ignition switch 50 whether or not the ignition switch 50 has just been turned on from off.

In step 61, step 65, which will be described later,
It is determined whether the ignition-off process has been completed.

[0035] At step 62, the ignition-on process, that is, as to turn on the control current i ₂ at the same time,
As shown in FIG. 7, the control current i ₁ is applied with a current value for obtaining a fail-safe pressure for a predetermined time (for example, 0.5 sec), and thereafter, the current value is gradually decreased.

In step 63, it is determined from the switch signal from the ignition switch 50 whether or not the ignition switch 50 has just been turned off from on.

In step 64, it is determined whether or not the ignition-on process in step 62 has been completed.

[0038] At step 65, ignition-off time of treatment, i.e., the current the control current i ₁ above, as shown in FIG. 8, gradually increased to the current value failsafe pressure is obtained, the fail-safe pressure is obtained Value for a given time
(For example, 0.5 sec)
The control current i ₁ to turn off the control current i ₂ at the same time as the OFF. Incidentally, if the fail-safe pressure of the control current i ₁ is obtained,
Predetermined time for maintaining the current value is increased control current i ₁
Considering the response delay of hydraulic pressure rise to
Set as sec. "

(Ignition ON) When the ignition switch 50 is turned on from the off state to the on state, the flow proceeds from step 60 to step 61 to step 62 in FIG.

That is, if it is detected immediately after the ignition is turned on in step 60, the condition in step 62 is that the ignition-off process is terminated.
The control current i ₂ to the on / off solenoid coil 46 is turned on, and at the same time, the control current i ₁ to the control solenoid coil 43 is changed from the current value at which the fail-safe pressure is obtained for a predetermined time, as shown in FIG. Then, solenoid control for gradually decreasing the current value is performed.

Therefore, when the ignition is turned off, the on / off solenoid coil 46 of the proportional electromagnetic pressure reducing valve 27 is not energized, so that the spring force of the fail-safe spring 48 acts on the spool 36 to generate a fail-safe pressure. the is, the fail-safe pressure is to decrease once the release of the spring force caused by the energization of the on-off solenoid coil 46 (P ₂ characteristic of FIG. 7).

However, the control current i ₁ for obtaining the fail-safe pressure is applied to the control solenoid coil 43 at the same time when the ON / OFF solenoid coil 46 is energized,
Solenoid force in place of the spring force oil pressure is generated will be acting on the spool 36 (P ₁ characteristics of Fig. 7).

As a result, the hydraulic pressure output from the control pressure port 39 of the proportional electromagnetic pressure reducing valve 27 to the wet multi-plate clutch 16 has the P (= P ₁ + P ₂ ) characteristic shown in FIG. A sudden drop in hydraulic pressure with a large head is suppressed.

(At the time of ignition off) When the ignition switch 50 is turned off from on to off, when the ignition is off, in FIG.
The flow proceeds from 3 → step 64 → step 65.

That is, if it is detected immediately after the ignition is turned off in step 63, on condition that the ignition-on time process in step 54 is completed, in step 65,
Predetermined control current i ₁ to the previously controlled solenoid coil 43, as shown in FIG. 8, gradually increased until the current value failsafe pressure is obtained, increases the value of the current fail-safe pressure is obtained, this the control current i ₂ to the on-off solenoid 46 is solenoid controlled to be turned off is performed at the time of the maintenance time.

Therefore, when the ignition was turned on, the on / off solenoid coil 46 of the proportional electromagnetic pressure reducing valve 27 was energized, and the spring force of the fail-safe spring 48 did not act on the spool 36. failsafe pressure is going to rise once by the action of the spring force caused by the non-energization of the on-off solenoid coil 46 (P ₂ characteristic of FIG. 8).

However, by applying the control current i ₁ to the control solenoid coil 43 before the fail-safe pressure rises due to the non-energization of the on / off solenoid coil 46,
A gradually increasing fail-safe pressure is generated (FIG. 8).
P ₁ characteristic of).

As a result, the hydraulic pressure output from the control pressure port 39 of the proportional electromagnetic pressure reducing valve 27 to the wet multi-plate clutch 16 has the P (= P ₁ + P ₂ ) characteristic shown in FIG. A sudden rise in hydraulic pressure with a large head is suppressed.

Next, the effects will be described.

In a vehicle hydraulic control unit provided with a proportional solenoid pressure reducing valve 27 having a fail-safe function having a proportional solenoid coil 43 and an on / off solenoid coil, an on / off solenoid coil 46 and a proportional solenoid coil 4 are provided.
3 and a solenoid control process when the ignition is turned off (step 65) and a solenoid control process when the ignition is turned off (step 65), and a sudden decrease / increase in hydraulic pressure due to energization / de-energization of the on / off solenoid coil 46 is proportionally performed. Since the device is controlled by the generation of hydraulic pressure by the control of the solenoid coil 43, it is possible to prevent the generation of abnormal noise in the wet multi-plate clutch 16 due to the rapid decrease and increase of the hydraulic pressure when the ignition is turned on and off.

Although the embodiment has been described with reference to the drawings, the specific configuration is not limited to the embodiment, and any changes or additions without departing from the gist of the invention are included in the invention. It is.

For example, in the embodiment, an example of application to the front and rear wheel drive torque distribution control system has been described. However, other control such as a hydraulic active suspension control system which requires a constant pressure maintenance at the time of a system failure is used. It can also be applied to systems.

[0053]

As described above, according to the present invention, in a vehicle hydraulic control unit provided with a proportional solenoid pressure reducing valve having a proportional solenoid and an on / off solenoid, the on / off solenoid and the proportional solenoid are relatedly controlled. A solenoid control means for ignition-on and a solenoid control means for ignition-off are provided. The effect that generation of a sound can be prevented is obtained.

[Brief description of the drawings]

FIG. 1 is a view corresponding to claims showing a vehicle hydraulic control unit of the present invention.

FIG. 2 is a diagram of a front and rear wheel drive torque distribution control system of a rear wheel drive base to which the vehicle hydraulic control unit of the embodiment of the present invention is applied.

FIG. 3 is a diagram showing a hydraulic unit of the embodiment.

FIG. 4 is a sectional view showing a proportional electromagnetic pressure reducing valve with a fail-safe function used in the hydraulic unit of the embodiment.

FIG. 5 is a block diagram of a solenoid control system when the ignition of the vehicle hydraulic control unit of the embodiment is turned on and off.

FIG. 6 is a flowchart showing a flow of a solenoid control processing operation at the time of ignition on / off performed by an ETS control unit.

FIG. 7 is a time chart of a control current and a hydraulic pressure showing control contents when an ignition is turned on.

FIG. 8 is a time chart of a control current and a hydraulic pressure showing control contents when an ignition is turned off.

[Explanation of symbols]

 a Hydraulic source b Spool c Proportional solenoid d On / off solenoid e Fail-safe spring f Proportional electromagnetic pressure reducing valve g Hydraulic actuator h Ignition on / off detection means i Ignition on solenoid control means j Ignition off solenoid control means

Claims (1)

(57) [Claims] A hydraulic pressure source, a spool, a proportional solenoid and an on / off solenoid, wherein when energizing the proportional solenoid, an input pressure from the hydraulic source is used as a control pressure in accordance with a magnitude of a current value, and an on / off solenoid is supplied to the on / off solenoid. A proportional electromagnetic pressure reducing valve that applies a spring force by a fail-safe spring to the spool when not energized to maintain a constant fail-safe pressure, and releases the effect of the spring force by the fail-safe spring to the spool when energizing the on / off solenoid; A hydraulic actuator driven by oil pressure from the proportional electromagnetic pressure reducing valve, an ignition on / off detecting means for detecting on / off of an ignition switch, and when detecting immediately after the ignition is turned on, energizing the on / off solenoid and obtaining almost fail-safe pressure at the same time Soleno When the ignition is turned on, the solenoid control means for applying a current to the proportional solenoid is applied. A hydraulic control unit for a vehicle, comprising: a solenoid control unit.