JP2817450B2 - Working fluid leakage prevention device for accumulator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention detects that a working fluid stored in an accumulator is leaking from a control valve for controlling communication and shutoff between the accumulator and an operating device, and stops the leak. A working fluid leakage prevention device ;
And a brake device having the working fluid leakage prevention device .

[0002]

2. Description of the Related Art Leakage of a working fluid from a control valve poses a problem in, for example, an automotive hydraulic brake system described in Japanese Patent Application No. 2-5736. This device is 4
This is an anti-skid / traction control type hydraulic brake device for wheeled vehicles. The accumulator pressure sensor for keeping the accumulator pressure (hereinafter simply referred to as the accumulator pressure) within an appropriate range, and the accumulator pressure has become abnormally low. And a pressure sensor for abnormal alarm for issuing an alarm by detecting the abnormality. When the working fluid of the accumulator is used as a working fluid, and the accumulator pressure becomes equal to or lower than the lower limit value of the appropriate range, the pump is started based on the output signal of the accumulator control pressure sensor, and the accumulator pressure reaches the upper limit value of the appropriate range. However, when the accumulator pressure does not start for some reason in response to the signal of the pressure sensor for accumulator control and the accumulator pressure falls to the abnormality determination reference value, the pressure based on the output signal of the abnormality alarm pressure sensor is used. Warnings are issued.

[0003] In the above hydraulic brake device,
An electromagnetic directional control valve for traction control is provided between the accumulator and the wheel cylinder as an operating device, and the wheel cylinder is disconnected from the reservoir to communicate with the accumulator, and a state in which hydraulic fluid is supplied from the accumulator, Is cut off from the accumulator and can be switched to a state of communicating with the reservoir. When this directional control valve is switched,
If foreign matter is caught between the valve and the valve seat and the valve cannot be seated on the valve seat, or if the valve is not seated at the correct position of the valve seat, the accumulator and the wheel cylinder Although the state is in a shut-off state, the working fluid of the accumulator may leak to the reservoir via the directional control valve. Even when this interruption failure occurs, the accumulator pressure is controlled based on the output signal of the accumulator control pressure sensor, and an alarm is issued based on the output signal of the abnormality alarm pressure sensor.

[0004]

However, in the above-mentioned apparatus, the working fluid stored in the accumulator has not been prevented from leaking from the directional control valve. Therefore, once the directional control valve shut-off failure occurs, the hydraulic fluid continues to leak until the next directional control valve operates, and even if the pump is operated to accumulate pressure, the accumulator pressure does not readily increase, and In some cases, even if the pump goes up, it will drop again if the pump is stopped. If the shutoff failure of the control valve occurs, the life of the motor or the relay is shortened by energizing the pump motor or the relay for a long time or the number of times of operation is increased, and energy is wasted. Problems arise. This problem generally occurs not only in the hydraulic brake device but also in a hydraulic device including a control valve such as a direction switching valve or an on-off valve and an accumulator for storing a working fluid under pressure.

Accordingly, a first object of the present invention is to provide a working fluid.
Accumulator that stores pressure under pressure and its accumulator
Control valve for controlling communication and shut-off between the actuator and the actuator
In the fluid pressure device, it is to obtain a working fluid leakage prevention device that detects that the working fluid of the accumulator is leaking from the control valve , and when the leak is detected, can stop the leak . The challenge is to prevent leakage of the working fluid
The application of the device to a braking device.

[0006]

The first object of the present invention is to operate
As shown in FIG. 1 , the fluid leakage prevention device includes: (a) a pressure accumulation leak detection means for detecting a working fluid leak of an accumulator and outputting a leak detection signal; and (b) a control valve in accordance with the leak detection signal. Leakage stopping means for operating at least one reciprocation
Is solved by including. Also the second
The problem is that accumulators that store hydraulic fluid under pressure
And hydraulically actuated actuators
Controls communication and cutoff between the accumulator and the actuator
Actuates with actuation of actuator, including control valve
In a braking device for braking a vehicle, the control valve
Hydraulic fluid in accumulator leaks when shut off
Accumulation leak detection that detects a leak and outputs a leak detection signal
Means and control valves at least according to the leak detection signal.
Also, by providing a leak stop means that operates one reciprocation,
Is resolved. In one embodiment of the present invention,
The accumulator of the brake device operates the brake operating member.
The hydraulic pressure source of the hydraulic booster that boosts
The tutor is in parallel with the hydraulic booster via the control valve
Connected to the accumulator. Also in another aspect
In addition to the above, the brake device further suppresses the rotation of the wheels.
A wheel cylinder that activates the braking
Wheel cylinder through the control valve
Liquid that is connected to the
Passage, the control valve of the passage and the wheel cylinder.
Between the wheel cylinders to control the hydraulic pressure of the wheel cylinders.
Hydraulic control valve device and wheel slip during vehicle acceleration
When the pressure becomes excessive, the control valve is
And the hydraulic pressure.
By controlling the control valve device, the wheel cylinder
Control the hydraulic pressure of
Action control means is provided.

[0007]

In the working fluid leakage prevention device constructed as described above, if the accumulator leak detecting means detects that the working fluid of the accumulator is leaking from the control valve, a detection signal is issued. Accordingly, at least one reciprocating operation of the control valve is performed by the leakage stopping means . Therefore, even if the working fluid is leaking because the valve of the control valve is not seated on the valve seat in a good state, the valve is normally seated on the valve seat by the operation of the control valve, and Also, when a foreign substance is caught between the valve seat and the seat, causing poor seating,
The foreign matter is caused to flow by the flow of the working fluid, or the foreign matter is crushed between the two by the collision of the valve element with the valve seat, thereby restoring the function of the control valve and eliminating the leakage of the working fluid. Also, in the brake device configured as described above,
If hydraulic fluid leaks from the control valve,
Need to replenish the hydraulic fluid to the
Increases lugi consumption and, in some cases, accumulate
Actuator does not operate properly due to insufficient
However, the occurrence of such a situation is
It is well prevented by the detecting means and the leak stopping means.
For example, as described above, the actuator is
The connected accumulator is the hydraulic pressure source of the hydraulic booster
In one aspect of the brake device, hydraulic fluid leaks into the control valve.
If this occurs, the operation of the hydraulic booster will be insufficient,
It is possible to operate the brake operating member with greater force than usual
Required, and the fluid in the wheel cylinder
Hydraulic control valve device for passage, and traction control
In the brake device having the means, the control valve
If hydraulic fluid leaks, traction control is performed normally
The situation that does not occur occurs, but such a situation occurs
Is well prevented.

[0008]

As described above, in the working fluid leakage prevention device of the present invention, since the working fluid of the accumulator is prevented from leaking from the control valve, the operation of the pump motor and the relay for restoring the accumulator pressure is prevented. The number of times is reduced, and an effect is obtained that the reduction of the service life and wasteful energy consumption are favorably avoided. Moreover, since the accumulated pressure leak detecting means and the leak stopping means can be realized by adding a simple electronic circuit or changing the control program of the computer, the above-mentioned effect can be obtained while suppressing an increase in the apparatus cost. Also, the operation of the control valve in the brake device
If liquid leakage is prevented, in addition to the above effects,
The effect of improving the reliability of is obtained. For example, hydraulic boo
Star and traction control device malfunction
Is avoided, and the braking device is
Since the equipment requires high reliability, its reliability is improved
The benefits of doing so are great.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An anti-skid / traction control type hydraulic brake device for a four-wheeled vehicle equipped with an accumulator hydraulic fluid leakage prevention device according to one embodiment of the present invention will be described in detail with reference to the drawings.

In FIG. 2, reference numeral 10 denotes a hydraulic booster (hereinafter simply referred to as booster), and reference numeral 12 denotes a tandem type master cylinder (hereinafter simply referred to as master cylinder). The master cylinder 12 has a housing 14. A first pressurizing piston 18 and a second pressurizing piston 20 are provided in a cylinder bore 16 formed in the housing 14.
Are fitted in a liquid-tight and slidable manner.
A first pressurizing chamber 22 and a second pressurizing chamber 24 are formed in front of 8, 20 respectively. The hydraulic pressure generated in the first pressurizing chamber 22 is supplied to the rear wheel cylinders 34 and 36 of the brakes of the left rear wheel 30 and the right rear wheel 32 via the liquid passage 28, while being generated in the second pressurizing chamber 24. The pressure of the fluids passed through the fluid passages 40 and 41
And is supplied to front wheel cylinders 46, 48 of the brakes of the left front wheel 42 and the right front wheel 44.

Between the rear wheel cylinders 34, 36 and the first pressurizing chamber 22, there are provided an electromagnetic directional control valve 50, electromagnetic hydraulic pressure control valves 52, 53, and front wheel cylinders 46, 4.
8 and the second pressurizing chamber 24, between the electromagnetic directional switching valves 54,5
5 and electromagnetic hydraulic pressure control valves 56 and 57 are provided.
The electromagnetic directional control valve 50 is connected to the power pressure chamber 63 of the booster 10 via the electromagnetic directional control valve 58 so that either the master cylinder pressure or the power pressure is supplied to the rear wheel cylinders 34, 36. Has become. In addition, the electromagnetic directional control valves 54 and 55 are also connected to the power pressure chamber 63, and either the master cylinder pressure or the power pressure is supplied to the front wheel cylinders 46 and 48.

As shown in FIG. 3, a valve chamber 58b extending in the axial direction is formed in a housing 58a of the electromagnetic directional control valve 58, and three ports 58c, 58d and 58e communicating with the valve chamber 58b are formed. Have been. The port 58c communicates with the electromagnetic direction switching valve 50 via the liquid passage 59, the port 58d communicates with the power pressure chamber 63 via the liquid passage 60, and the port 58e communicates with the accumulator 64 via the liquid passage 61, respectively. An on-off valve 58f is provided between the chamber 58b and an on-off valve 58g is provided between the port 58e and the valve chamber 58b. Valve chamber 58b
A valve member 58 having valve elements 58h and 58i at both ends.
j is movably held in the axial direction, the valve 58i is normally seated on the valve seat 58m by the urging force of the spring 58k, the on-off valve 58g is closed, and the valve 58h is separated from the valve seat 58n. The opening and closing valve 58f is opened.
Therefore, the liquid passage 60, the port 58d, the valve chamber 58b,
The power pressure chamber 63 communicates with the electromagnetic directional control valve 50 via the port 58c and the liquid passage 59.

An armature 58p is fixed to the outer peripheral surface of the valve member 58j. When an exciting current is supplied to the solenoid 58q held in the housing 58a, the valve member 58j resists the urging force of the spring 58k. Then, the valve moves in the valve chamber 58b, the valve element 58h is seated on the valve seat 58n, and the on-off valve 58f is closed, while the on-off valve 58g is opened. Thereby, the electromagnetic directional control valve 50 and the power pressure chamber 63 are shut off, and the accumulator 64 communicates with the electromagnetic directional control valve 50. This switching is performed when traction control is required, and the brake fluid, which is the working fluid accumulated in the accumulator 64, is supplied to the fluid passage 61,
The fluid flows through the port 58e, the valve chamber 58b, the port 58c, and the liquid passage 59 to the electromagnetic directional control valve 50, and is supplied to the rear wheel cylinders 34 and 36 which are operating devices.

These electromagnetic directional valves 50, 54, 55,
Switching between the valve 58 and the electromagnetic hydraulic pressure control valves 52, 53, 56, 57 is performed by a control device 65 described later in detail. Each of the electromagnetic hydraulic pressure control valves 52, 53, 56, and 57 can be switched to three positions.
2, 42 and 44 are anti-skid controlled,
Traction control is performed on the left and right rear wheels 30, 32, which are drive wheels. That is, each wheel 30, 32,
The rotation speed of each of the rotation sensors 42 and 44 is detected by each rotation sensor 66, and an output signal thereof is supplied to a control device 65, and by switching the electromagnetic hydraulic pressure control valves 52, 53, 56 and 57 based thereon, the wheel cylinders 34, 36 and. By increasing, maintaining and decreasing the hydraulic pressures of the wheels 46 and 48, the slip of the wheels is maintained in an appropriate range. However, since this switching is a well-known control, a detailed description is omitted. . Note that a proportioning valve 68 is provided between the first pressurizing chamber 22 and the electromagnetic direction switching valve 54.

The second pressurizing chamber 24 and the electromagnetic directional control valve 5
A pressure control cylinder 70 is provided between the pressure control cylinders 4 and 55, and a pilot control on-off valve 74 is connected between the pressure control cylinder 70 and the power pressure chamber 63 of the booster 10 by a liquid passage 72 and a liquid passage 60. Have been. A differential pressure switch 76 is provided between the liquid passage 41 and the liquid passage 72.
When the power pressure is normal, the pilot control on-off valve 74 closes, so that the volume of the pressure-intensifying control liquid chamber of the pressure-intensifying cylinder 70 is prevented from decreasing. As a result, the pressure-intensifying cylinder 70 cannot perform the pressure-increasing action, and the hydraulic pressure in the second pressurizing chamber 24 is transmitted to the liquid passage 41 as it is. Also, the liquid passage 4
Since 1 and the liquid pressure of the liquid passage 72 are substantially equal, the differential pressure switch 76 does not operate. On the other hand, if the power pressure fails, the pilot-controlled on-off valve 74 opens,
The pressure-intensifying cylinder 70 is in a state capable of performing the pressure-increasing action, and the hydraulic pressure in the second pressurizing chamber 24 is increased and transmitted to the liquid passage 41. Further, since the liquid pressure in the liquid passage 41 becomes considerably higher than the liquid pressure in the liquid passage 72, the differential pressure switch 76 operates to output a signal indicating the failure of the power pressure. These pressure-increasing cylinder 70, pilot-controlled on-off valve 74, differential pressure switch 7
The structure of No. 6 is described in detail in the specification of Japanese Patent Application No. 61-172568.

The housing 14 of the master cylinder 12
Are fitted in fitting holes 82 of the housing 80 of the booster 10. As a result, the cylinder bore 84 of the housing 80 is in communication with the cylinder bore 16, and the power piston 86 is provided in the cylinder bore 84 with the second pressure piston 2.
0 and are fitted in a liquid-tight and slidable manner,
The operating force of the power piston 86 is transmitted to the second pressurizing piston 20 by the relay rod 88.
On the other hand, the power pressure chamber 63 is formed behind the power piston 86 of the cylinder bore 84. A reaction piston 94 is fitted in a bottomed hole 92 formed in the small diameter portion 90 of the power piston 86 in a liquid-tight and slidable manner.
6, while the rear end is connected to a brake pedal 98 as a brake operating member. Depress the brake pedal 98 with the brake switch 1
00, and the output signal is supplied to the control device 65.

The booster 10 further includes a control valve 110. The valve spool 112 of the control valve 110 is engaged with the power piston 86 and the reaction piston 94 by a lever device 114. As a result, a power pressure corresponding to the operation force applied to the input rod 96 is generated in the power pressure chamber 63, and the power piston 86 is operated.

The accumulator 64 has a reservoir 11
6 is supplied by a pump 122 driven by a motor 120. The check valve 124 prevents the brake fluid stored in the accumulator 64 from flowing back to the pump 122, and the relief valve 126 prevents the accumulator pressure from becoming abnormally high. Further, the accumulator 64 has a pressure switch 1
30 and a pressure switch 132 are provided. The characteristics of each of the pressure switches 130 and 132 are shown in a graph in FIG. As is clear from the graph, a hysteresis region is set in each of the characteristics of the pressure switches 130 and 132. Pressure switch 130 is used for accumulator control to control motor 120 such that brake fluid is stored in accumulator 64 within the proper hydraulic pressure range, while pressure switch 132 is used for accumulator pressure where the accumulator pressure is below the lower limit of the appropriate hydraulic pressure range. Used to determine whether an abnormality has occurred. When it is determined that a pressure accumulation abnormality has occurred, the driver is notified of this by a warning buzzer 134 and a warning lamp 136.

The pressure switches 130 and 132, the warning buzzer 134 and the warning lamp 136 are connected to the control device 6
5 is connected. The control device 65 is mainly composed of a computer, and has an input interface 140, an output interface 142, and a CPU 14 as shown in FIG.
4, a ROM 146 and a RAM 148. The input interface 140 is connected to the rotation sensor 66, the differential pressure switch 76, the brake switch 100, the pressure switches 130 and 132, and the like, and the output interface 142 is connected to the electromagnetic direction switching valves 50, 54, 55,
Along with the electromagnetic hydraulic pressure control valves 52, 53, 56, 57, etc., the solenoid 58q of the electromagnetic directional control valve 58, the motor 120,
A warning buzzer 134, a warning lamp 136 and the like are connected. The ROM 146 stores control programs for the anti-skid control, traction control, and pressure accumulation control (not shown), as well as control programs represented by the flowcharts in FIGS. 6, 7, 8, and 9. The RAM 148 has a solenoid flag F shown in FIG.
Various storage areas including sol are provided.

The control device 65 configured as described above includes:
In addition to brake fluid pressure control such as traction control and anti-skid control, as well as pressure accumulation control based on the output signal of the pressure switch 130 and control of the warning buzzer 134 and the warning lamp 136 based on the output signal of the pressure switch 132, the pressure switch 130, The brake fluid in the accumulator 64 is supplied to the electromagnetic directional control valve 5 based on the output signal of the
8 to detect leakage and perform leakage prevention control for reciprocating the electromagnetic directional control valve 58 a plurality of times in accordance with the control program.

The on-off valve 58g of the electromagnetic directional control valve 58 is always closed. However, foreign matter enters the on-off valve 58g, and the valve seat 58m and the valve 58
i, the valve 58i does not completely seat, and the on-off valve 58g is not completely closed, and the accumulator 6 passes through the on-off valve 58g and the on-off valve 58f in the open state.
4 communicates with the power pressure chamber 63, and the brake fluid in the accumulator 64 leaks to the reservoir 116 through the power pressure chamber 63. Similarly, when the valve 58i is not properly seated on the valve seat 58m and the on-off valve 58g is not completely closed, leakage of the brake fluid also occurs. The leak prevention control according to the present embodiment is performed to solve this inconvenience.

Hereinafter, the present invention will be described in detail with reference to flowcharts shown in FIGS. The execution of the leak prevention control is shown in FIG.
Is performed every 20 msec according to the main routine of FIG. First, in step S1 (hereinafter simply referred to as S1; the same applies to other steps), initial settings are performed.
As shown in FIG. 7, various flags in the RAM 148
At the same time, the solenoid flag Fsol is turned off, the solenoid 58q of the electromagnetic switching valve 58 is turned off, and the accumulator-side opening / closing valve 58g of the electromagnetic switching valve 58 is closed. Subsequently, after measuring the initial time in S2, the leak detection / stop control is executed in S3.

The measurement of the initial time in S2 is provided to prevent the leakage detection / stop control in S3 from being performed for a fixed time immediately after the start of the engine of the automobile.
This is performed based on the flowchart of FIG.

[0024] First, if the ignition switch is ON the engine (not shown) is started, the determination result is YES in S20, whether the initial time flag F ₁ is ON is determined at S21. Result becomes NO in the first determination, but whether t ₁ measured flag F ₂ step S22 is ON is determined, since the result of the determination becomes NO, the initial time t ₁ to the timer 150 in S23 Is set and t is set in S24.
₁ Measurement flag F ₂ is ON. Initial time t ₁ is a predetermined time since the start of the engine, t ₁ measured flag F ₂ is after an initial time t ₁ is set once, the set of initial time t ₁ is carried out until the 0 It is not to be.

Subsequently, in S25, the initial time t ₁ becomes 1
Reduced, whether initial time t ₁ is 0 is determined at S26. The first determination result is NO, and one execution of the initial time measurement program ends. Again S22
Is executed, the result of the determination is YES, and S23, S
24 is skipped and the initial time t is further increased at S25.
_One is reduced by one. In this way, the elapse of the initial time t ₁ is waited. If the initial time t ₁ elapses, the determination result in S26 becomes YES, and in S27, the t ₁ measuring flag F ₂
Is turned off and the initial time lapse flag F ₁ is set to O.
N.

The leak detection / stop control in S3 is performed based on the flowchart of FIG. 9, and comprises a leak detection process in S28 to S50 and a valve reciprocating operation process in S52 to S65. Leak detection process, the pump 122 even after the lapse of the reference pump operating time t ₂ when the pump 122 if there is no leakage of extent in question may well increase the accumulator pressure to the upper limit of the proper range continues to operate S28 and S3 that brake fluid leakage has occurred
And routine 3～S36, the pump 122 is operated within a reference pump stop time t ₃ can not have decreased to the lower limit value become the accumulator pressure from the pump 122 if no leak is stopped the extent that proper range problem S29, S3 detecting that the brake fluid has started and determining that the brake fluid is leaking.
2, S33 and S39 to S48, and S30, S31, S49 and S50, which are routines for detecting the occurrence of a pressure accumulation abnormality by the pressure switch 132 and determining that the brake fluid is leaking. ing.

Specifically, leakage is detected when any of the following conditions (1) to (4) is satisfied. Pump 122 after the reference pump operating time t ₂ elapses even ON pump 122 is a reference pump stop time t ₃ within O
N ・ Brake switch 100 is OFF ・ Anti-skid control is not in progress ・ Traction control is not in progress ・ Pressure switch 132 is OFF ・ Initial time t ₁ elapses after ignition switch is turned ON ・ Constant time t ₆ elapses after execution of valve reciprocating operation processing

First, a routine for determining whether the condition is satisfied will be described. In S28, the leak detection flag F
₃ is to determine whether the leak detection flag F ₄ is ON in S29 and whether the leak detection flag F ₇ is ON in S30. Although each flag will be described later, since all of these determination results are initially NO, in S31, the accumulator pressure reaches the lower limit value of the hysteresis area of the pressure switch 132 as shown in the right end of FIG. The pressure switch 132 outputs an OFF signal, and it is determined whether the warning buzzer 134, the warning lamp 136, and the like are in the ON state.

[0029] In automotive specifications engine is stopped even accumulator 64 is maintained in the accumulator state, since normally this determination result is NO, and in S32, whether t ₃ measurement flag F ₅ is ON Is determined. Since the first determination result is NO, whether the pump 122 is operating in S33,
It is determined whether the motor 120 that operates the motor 22 is in the ON state. Result is YES determination if the motor 120 is turned ON, the pump 122 in the S34 is a determination whether the reference pump operating time t ₂ has elapsed since the start is performed. The reference pump operation time t ₂ is determined to be a length that can normally increase the accumulator pressure to the upper limit of the appropriate hydraulic pressure range if the motor 120 is driven for that time (unless there is a problematic leak). ing.
The capacity and temperature of the accumulator 64, the discharge amount of the pump 122, and the like are taken into consideration, and the traction control or the anti-skid control is performed during the pressure increase. The determination in S34 is
It is performed in the same manner as lapse determination of the initial time t ₁ of FIG.

Normally, the pump 122 is turned off before the reference pump operation time t ₂ elapses.
As shown in the left part of, if the reference pump working pump 122 is actuated state even time t ₂ has elapsed, S34 the determination result of determination is NO, the S35 with becomes YES, and the leakage detection flag at S36 F ₃ is ON,
The valve reciprocating operation process from S52 is executed. That the pump 122 after a lapse of the reference pump operating time t ₂ is in operation is that the accumulator pressure based pump operating time t within ₂ has not increased to the upper limit of the proper pressure range, It is determined that the leakage of the brake fluid has occurred. The S28 in decision result after the leakage detection flag F ₃ is ON (YES) is obtained, S29～S36
Is skipped, and S52 and the subsequent steps are executed.

Next, a routine for determining whether or not the above condition is satisfied will be described. Brake fluid in the accumulator 64 is accumulated successfully pump 1 within the reference pump operating time t ₂
22 the determination result is NO next S33 as long stopped, the reference pump stop time t ₃ is set in the timer 152 in S39. Then the t ₃ Measurement flag F ₅ is ON in S40, after the reference pump stop time t ₃ is reduced 1 in S41, the pump 12 step S42
It is determined whether or not 2 has been activated. If the result of the determination is NO, one execution of the program ends, and then S
32 whether t ₃ measurement flag F ₅ is in the ON state at. Since the result of this determination is YES, S
39 and S40 are skipped, and S41 and S42 are executed again.

If the pump 122 is in the operating state while the program is repeatedly executed in this manner, S42 is executed.
The determination result is YES, with t ₃ measurement flag F ₅ is OFF in S43, whether the reference pump stop time t ₃ is greater than or equal to zero is determined at S44. After the brake fluid in the accumulator 64 is stopped temporarily is accumulated pressure pump 122, the time to the accumulator pressure starts to operate again lowered it is common that a substantial long, the reference pump stop time t ₃ The length is set based on the normal pump stop time. Therefore, if the brake fluid has not leaked from the accumulator 64, the pump 122 starts up after the reference pump stop time t ₃ has elapsed, and the reference pump stop time t 3
_{Since 3} is a negative value, the execution of the routine for which the determination result in S44 is NO is ended. However, if the accumulator 64 is leaked, the accumulator pressure decreases before the reference pump stop time t ₃ elapses and the pump 122 starts operating, as shown in the center of FIG. the value of the stop time t ₃ becomes 0 or more, the result of the determination becomes YES, and a determination is made S45 to S47.

[0033] Since even the accumulator 64 is leaking a slight amount of brake fluid, it only the pump 122 within the reference pump stop time t ₃ is in is not activated, S44
Is NO, and the valve reciprocating operation processing after S52 is not executed. However, if the brake operation, anti-skid control or traction control is performed and the brake fluid of the accumulator 64 is consumed when such a leak is generated, the reference pump stop time t ₃ is not elapsed before the reference pump stop time t ₃ elapses. The pump 122 starts operating and the result of the determination in S44 may be YES. In this case, since the valve reciprocating operation processing is unnecessary, the determination in S45 to S47 is performed.

In S45, it is determined whether or not the brake is being operated based on whether or not the brake switch 100 is ON, and whether or not anti-skid control is being executed in S46 and whether or not traction control is being executed in S47. Is determined. These determination, anti-skid control or the like is performed by a not-shown control program stored in the ROM146 of the control device 65, the anti-skid control flag F _A or traction control flag F _T is checked whether it is ON, respectively This is done by: And these S4
5, S46, all the determination result of S47 is ON leakage detection flag F ₄ in S48 only if was NO, the valve reciprocating processing after S52 is executed. The S29 in the determination result after the leakage detection flag F ₄ is turned ON YE
S is reached, S30 to S48 are skipped, and S52 is executed.

[0035] Incidentally, the accumulator pressure when the brake operation or the like is performed is not become less than the lower limit of the proper range, in the case of equal to or less than the lower limit value by a slight leakage after the ON leakage detection flag F ₄ Although the valve reciprocating operation process is executed, the probability that such a situation occurs is low, and even if such a situation occurs and the valve reciprocating operation process is performed, useless valve operation is performed. There is no problem.

Next, a description will be given of a routine for determining whether the condition (1) is satisfied. When the engine is not operated for a long period of time, not only in a vehicle in which the accumulated pressure of the accumulator 64 is released at the same time as the engine is stopped, but also in a vehicle in which the accumulated pressure is not released, the accumulator pressure becomes lower. As shown at the right end of FIG. 11, since the pressure is lower than the lower limit of the hysteresis range of the pressure switch 132, the warning buzzer 134 and the warning lamp 136 are activated for a certain period immediately after the start of the engine. Accordingly, the determination result is YES in S31, in S49, in S2 of the main routine of FIG. 6, the initial time flag F ₁ indicating the lapse of the initial time t ₁ is O
Whether it is N is determined, if it later S50 if it is not ON is skipped, even though the alarm buzzer 134, and the like initial time t ₁ has elapsed is in the operating state, S49 Is YES, and S5
S52 since been ON leakage detection flag F ₇ is performed at 0. Leak detection flags F ₃ and F ₄ are OFF
After the leakage detection flag F ₇ is ON in the state S30 in the determination result becomes YES, and the valve reciprocating processing after S52 is executed. Incidentally, after the execution of the valve reciprocating operation process,
The reason why the condition of “the fixed time t _{6 has} elapsed” will be described later.

Next, the valve reciprocating operation processing will be described. As described above, the valve reciprocating operation process includes the leak detection flags F _3, F
_4, than either F ₇ is executed when ON, excited between solenoid 58q solenoid ON time t _4, by repeating the current control demagnetizing between the solenoid OFF time t _5, the electromagnetic direction switching The valve 58 is operated N times.

First, in S52 and S53, it is determined whether the anti-skid control or the traction control is being performed.
In 53a, whether the valve processing flag F ₈ indicating that the operating process of the N reciprocating is started in the directional control valve 58 is ON determination is made. Initially the determination result is NO, then solenoid flag Fsol is ON with the valve operation flag F ₆ is ON in S54,
Valve processing flag F ₈ is turned ON at S54a. During execution of the anti-skid control or the traction control, the operation of the electromagnetic directional control valve 58 for preventing leakage is not performed.

When the solenoid flag Fsol is turned on, an exciting current is supplied to the solenoid 58q of the electromagnetic directional control valve 58 to excite the solenoid 58q and the valve member 5
8j moves to the on-off valve 58f side. Therefore, the on-off valve 58f on the power pressure chamber 63 side is closed, and the on-off valve 58g on the accumulator 64 side is opened. Subsequently, in S55, it is determined whether or not the count value n of the counter 156 is N. The count value N is set to a suitable number of times the electromagnetic directional switching valve 58 is switched. Initially the result of the determination is NO
Next, although the valve operation flag F ₆ in S56 is whether the determination is ON is performed, the determination result is YES
Since the solenoid ON time t ₄ is set in the timer 154 in S57, the elapsed is awaited. When the program is next executed, the determination result in S53a becomes YES, S54 and S54a are skipped, and S55 and subsequent steps are executed.

[0040] If the solenoid ON time t ₄ has passed S5
7 the determination result is YES, it is OFF the solenoid flag Fsol in S59 together with the valve operation flag F ₆ is OFF in S58, the electromagnetic directional control valve 58
The excitation current to the solenoid 58q is cut off, and the on-off valve 58g is closed by the urging force of the spring 58k. Subsequently, in S60, the count value n is incremented by one, and one process ends. If the count value n has reached the number of times of switching N, the determination result of S55 is YES and S64 is executed. Otherwise, S56 is executed again. Valve operation flag F ₆ because it is OFF in the previous S58, the result of this determination is NO, is set a solenoid OFF time t ₅ the timer 152 in S61,
The progress is awaited. The determination result is YES in S61 if the solenoid OFF time t ₅ is passed, along with the ON valve operation flag F ₆ again in S62, the solenoid flag Fsol is ON in S63, switching of the electromagnetic directional control valve 58 is performed . In this way, the excitation of the solenoid 58 q, by degaussing is performed repeatedly by a predetermined time, after the on-off valve 58g of the electromagnetic directional control valve 58 is opened between the solenoid ON time t _4, the solenoid OF
It is repeated N times which is closed during the F time t _5.

By performing the N reciprocating operation of the electromagnetic directional switching valve 58 in this manner, foreign matter that has entered the switching valve 58 is washed away by the brake fluid in the accumulator 64, or the valve element is opened and closed by the on-off valve 58g. 58i,
By being crushed between the valve seats 58m, the on-off valves 58f, 5
8 g is returned to the normal valve closing state. In addition, valve 5
Even if leakage occurs due to the poor seating state of the valve seat 8i on the valve seat 58m, the valve element 58i will be seated on the valve seat 58n well, preventing leakage of brake fluid from the on-off valve 58g. can do.

[0042] If the operation of the N reciprocating ends, the determination result of S55 is YES, the predetermined time t ₆ after the completion of valve operation in the timer 154 is set at S64, the elapsed is awaited. If the reciprocating operation of the electromagnetic directional control valve 58 is performed based on the warning of the abnormal decrease in the accumulator pressure, the accumulator pressure is still low immediately after the operation is completed. Flag F
If F _3, F _4, etc. are turned off, the determination result of S31 becomes Y
The state becomes ES, and the reciprocating operation is performed again. In order to prevent this, a fixed time t ₆ elapses after the reciprocating operation is completed, and the electromagnetic directional control valve 58 is reciprocated by the reciprocating operation.
The leak detection is not performed until it is determined whether or not the leak of the valve has been stopped. Among the conditions, “the predetermined time t ₆ after the execution of the valve reciprocating operation process” The condition "elapse" is satisfied. Note that the pump operating time is longer than the reference pump operating time t _2, or pump stop time reference pump stop time t
_{If the} reciprocating operation is performed due to being shorter than _{3, the} leakage detection flags F _3, F
₄ is never turned on.

If the predetermined time t ₆ has elapsed, the result of the determination is Y
ES, the leak detection flag F
_3, F ₄ , F _{7, the} valve operation flag F ₆ and the valve processing flag F ₈ are turned off, the count value n of the counter 156 is reset to 0, and one valve reciprocating operation process ends.

After the execution of the series of reciprocating operations has been completed and a predetermined time t ₆ has elapsed, the determination result in S31 is still YE.
When S is reached (in this case, the result of the determination at S49 is also YES), it is determined that the reciprocating operation is insufficient, the brake fluid is still leaking from the electromagnetic directional control valve 58, and the leak is determined at S50. The detection flag F ₇ is turned on, and S
The valve reciprocating operation routine of 52 to S65 is executed.

As is apparent from the above description, in this embodiment, the CPU 144 of the control device 65 and the RAM 14
8 and the part of the ROM 146 that executes the leak detection routine of S28 to S50 constitute the pressure accumulation leak detection means of the present invention, and the part of the same that executes the valve reciprocating operation routine of S52 to S65 constitutes the leakage stop means of the present invention. ing. A brake fluid leakage prevention device for preventing the brake fluid stored in the accumulator 64 from leaking from the electromagnetic directional control valve 58, which is a control valve, in cooperation with the pump 122, the motor 120, the pressure switches 130, 132, and the like. -ing In addition, the electromagnetic hydraulic pressure control valve 52,
53 constitutes a hydraulic pressure control valve device, and the CPU 144, R
Traction control of AM 148 and ROM 146
The part that executes the program for the traction control means
Make up.

Next, another embodiment of the present invention will be described. The same members as those in the above embodiment are denoted by the same reference numerals, and the detailed description is omitted.

In this embodiment, a linear pressure sensor 200 is provided instead of the pressure switches 130 and 132 as shown in FIG. Linear pressure sensor 200
13 can output a signal proportional to the accumulator pressure, as shown in FIG. 13. Therefore, by providing the rising gradient table 202 and the leakage gradient table 204 in the ROM 146 of the control device 65 in FIG. Pressure leaks can be detected. The rising gradient table 202 shows a reference rising gradient α ′ determined by the accumulator pressure rising characteristics shown by the broken line in FIG. 15 when the pump is operated in a state where the electromagnetic directional control valve 58 is slightly leaked.
Is stored in association with the accumulator pressure at each time, and the leak gradient table 204 stores a reference leak gradient β ′ determined from the accumulator pressure decreasing characteristic when a slight leak occurs when the pump is stopped at each time. And stored in association with the accumulator pressure. RAM 14
8, each storage area is provided as shown in FIG.

Accordingly, the linear pressure sensor 200 detects the accumulator pressure and its rising gradient α or leakage gradient β, and the tables 202 and 204 are stored based on the flowchart shown in FIG.
The leakage of the brake fluid from the electromagnetic directional control valve 58 is detected by comparing with the reference gradients α ′ and β ′ stored in. In this embodiment, the linear pressure sensor 200 and the CPU 144 of the control device 65, the RAM 148, and the ROM 146 of the flowchart described below
The part that executes steps S68 to S88 constitutes a leak detection unit.

Hereinafter, description will be made with reference to the flowchart of FIG. First, the determinations in S68 and S69 are performed. Only when the brake fluid of the accumulator 64 is not consumed, the determination after S70 is performed. In S70 whether the pump 122 is operating is determined, whether the leakage detection flag F ₁₀ in S71 if the determination result is YES is ON is determined. The first determination result is NO, and the elapse of the detection time Δti is waited in S72.
Although the linear pressure sensor 200 is provided with a low-pass filter that removes high-frequency noise, it is still difficult to completely remove the noise, and the accumulator pressure also pulsates to some extent. The detection time .DELTA.ti is made longer than the cycle time in the flowchart of FIG. 16 in order to eliminate the influence of the above and detect the true rising gradient of the accumulator pressure.

After a lapse of the detection time Δti, the current detection value Pi stored in the current detection value area 206 of the RAM 148 is stored in the previous detection value area 208 as the previous detection value Pi-1 in S73, and the accumulator is stored in S74. The pressure is detected and stored in the present detection value area 206 as the present detection value Pi. Subsequently, in S75, a calculation of the ascending gradient α is performed. That is, the value obtained by dividing the difference between the present detection value Pi and the previous detection value Pi-1 by Δti is defined as the rising gradient α and the rising gradient area 210 of the RAM 148 is determined.
It is stored in. Then, in S76, the ascending gradient α is compared with the reference ascending gradient α ′ associated with the current detected value Pi stored in the current detected value area 206 in the ascending gradient table 202, and α is compared with α ′.
If the above is determined that the leakage in the directional control valve 58 does not occur, the leakage detection flag F ₁₀ is not ON. On the other hand, alpha becomes lower than if smaller increase rate is normal accumulator pressure than [alpha] ', the determination result is leakage detection flag F ₁₀ in S77 becomes YES is ON. Then, in S78, it is determined whether or not the brake switch 100 is ON, and in S79, the traction control flag F
It is determined whether or not _T is ON, and if both determination results are NO, the valve reciprocating operation processing as shown in the flowchart of the above-described embodiment is performed.

On the other hand, if the pump 122 is stopped in S70, the result of the determination is NO, and S80 to S8
In step S85, the leakage gradient β is detected in the same manner as the rising gradient α, and in step S85, the reference leakage gradient β ′ stored in the leakage gradient table is compared with the leakage gradient β. β is β
If 'less leakage detection flag F ₁₁ for leak has not occurred it is not ON. In contrast, the result of the determination is YE
S, i.e., β is greater than .beta. ', The leakage detection flag F ₁₁ in S86 is turned ON, if none S87, S88 of the determination result is NO, likewise the valve reciprocating process is performed.

Although the two embodiments of the present invention have been described above, it is also possible to perform a leak detection process including the following three leak detection routines. That is, this leak detection processing is performed by (a) the reference pump operating time t ₁₀ (for example, 240) in which the pump 122 can sufficiently increase the accumulator pressure to the upper limit of the appropriate range if there is no problematic leak.
It is detected that the pump 122 continues to operate even after the elapse of s), and the routine that determines that the leakage of the brake fluid has occurred, and (b) the accumulator pressure has increased to the upper limit value of the appropriate range even once. Later, the ignition switch is turned on
The routine detects that the brake fluid has leaked from the lower limit of the proper range while maintaining the state, and determines that the brake fluid is leaking, and (c) the accumulator pressure is increased even though the ignition switch is turned on. The routine is configured to detect that the brake fluid has not risen to the upper limit of the appropriate range and determine that the brake fluid is leaking.

More specifically, before the leak detection process is determined and after the valve reciprocating operation process is completed, the following (a) to (c) will be described.
When either of the conditions is satisfied, leakage is detected. (A) · pump 122 is a reference pump operating time t ₁₀ elapses after the ON (b) · Pressure switch 132 has a high-pressure storage of OFF · pressure switch 132 (c) · Pressure switch 132 is OFF · ignition switch after ON, Although the initial time t ₁₁ (for example, 80 s) has elapsed, the condition of “the pressure switch 132 has a high-pressure memory” is satisfied if the pressure switch 132 is in the ON state for a certain time t ₁₂ (for example, 9 s). ignition switch is released when it is OFF, ON for a predetermined time t ₁₂ the pressure switch 132 is again
It does not hold until the state is reached.

If any one of the above three conditions (a) to (c) is satisfied, the anti-skid control or the traction control is not being executed, and the abnormality of the solenoid 58q of the electromagnetic directional control valve 58 due to diagnosis. After it is determined that no serious defect has been found, valve reciprocating operation processing is executed in the same manner as in the previous embodiment.

In each of the above embodiments, the number of executions of the valve reciprocating operation process from the time the ignition switch is turned on to the time the ignition switch is turned off is stored in the control device 65 or the like. When the number of times exceeds the set number, an alarm can be issued to notify the driver of the abnormality. Further, the leak detection / stop control may be incorporated in a part of the diagnosis.

Although a plurality of embodiments of the present invention have been described above, the present invention can be applied to control valves other than the electromagnetic directional control valve 58. The present invention may be applied to a pressure device. In addition, the present invention can be implemented in various modified and improved modes based on the knowledge of those skilled in the art.

[Brief description of the drawings]

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

FIG. 2 is a system diagram showing an anti-skid / traction control type hydraulic brake device for a four-wheel vehicle provided with a hydraulic fluid leakage prevention device according to one embodiment of the present invention.

FIG. 3 is a front sectional view showing the electromagnetic directional control valve in FIG. 2;

FIG. 4 is a graph showing characteristics of each pressure switch in FIG.

FIG. 5 is a graph conceptually showing the control device in FIG. 2;

FIG. 6 is a flowchart showing only a portion that is relevant to the present invention extracted from a program stored in the ROM of the control device.

FIG. 7 is a flowchart showing only a portion related to the present invention, which is extracted from a program stored in the ROM of the control device.

FIG. 8 is a flowchart showing only a portion related to the present invention, which is extracted from a program stored in the ROM of the control device.

FIG. 9 is a flowchart showing only a portion related to the present invention, which is extracted from a program stored in the ROM of the control device.

FIG. 10 is a block diagram conceptually showing the configuration of a RAM.

FIG. 11 is a graph showing a change in accumulator pressure in the hydraulic brake device.

FIG. 12 is a system diagram showing a part of a hydraulic brake device including a hydraulic fluid leakage prevention device according to another embodiment of the present invention.

FIG. 13 is a graph showing characteristics of a linear pressure sensor of the device.

FIG. 14 is a graph conceptually showing the control device in FIG.

FIG. 15 is a graph for explaining a table stored in a ROM of the control device.

FIG. 16 shows a program stored in the ROM.
It is a flowchart which extracts and shows only the part deeply relevant to this invention.

FIG. 17 is a diagram conceptually showing a configuration of the RAM.

[Explanation of symbols]

 58 electromagnetic directional control valve 64 accumulator 65 control device 120 motor 122 pump 130 pressure switch 132 pressure switch 200 linear pressure sensor

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B60T 13/14 B60T 17/00 F15B 1/02

Claims (4)

(57) [Claims] 1. An accumulator for storing a working fluid under pressure, and a control valve for controlling communication and shutoff between the accumulator and the operating device. The accumulator is operated from a control valve in a shutoff state. A working fluid leak prevention device for preventing fluid from leaking, comprising: a pressure accumulation leak detecting means for detecting a working fluid leak of an accumulator and outputting a leak detection signal; and at least the control valve according to the leak detection signal. A leakage stop means for performing one reciprocating operation. 2. An accumulator for storing a hydraulic fluid under pressure.
When, A hydraulically actuated actuator, Communication and disconnection between these accumulators and actuators
Control valve for controlling the operation of the actuator
This is a brake device that operates with
hand, The accumulator with the control valve in the shut-off state
Leakage of hydraulic fluid and outputs a leak detection signal
Accumulator leak detection means, The control valve is operated at least once in response to the leak detection signal.
Leakage stopping means for resuming operation.
Rake equipment. 3. The brake operating unit according to claim 2, wherein the accumulator is a brake operating unit.
The hydraulic pressure source of the hydraulic booster that boosts the operating force of the material
The actuator is connected to the hydraulic valve via the control valve.
Connected in parallel with the accumulator
The brake device according to claim 2. 4. Further, A wheel system that activates a brake that suppresses wheel rotation
With Linda, The wheel cylinder is transferred to the accumulator through the control valve.
Function as the actuator by connecting to the
A liquid passage; Between the control valve and the wheel cylinder in the liquid passage
Is provided in the part of Control the hydraulic pressure of the wheel cylinder
A hydraulic pressure control valve device, If the slip of the wheels becomes excessive when the vehicle accelerates,
The control valve is connected to the hydraulic pressure control valve device and the accumulator.
And the hydraulic pressure
By controlling the control valve device, the wheel series is controlled.
Control the hydraulic pressure of the
Traction control means that performs
The brake device according to claim 2 or 3.