JPH0611271Y2 - Brake fluid pressure control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial field of application" The present invention relates to a brake hydraulic pressure control device for controlling the hydraulic pressure of each brake cylinder corresponding to a front wheel and a rear wheel of a vehicle, and more particularly to a brake cylinder. The present invention relates to a brake hydraulic pressure control device including an electromagnetic hydraulic pressure control device that electromagnetically controls the hydraulic pressure.

"Prior Art" A brake fluid pressure control device that electrically controls the hydraulic pressure level of a brake cylinder is known. For example, Japanese Patent Application No. Sho 62
This is the one described in the specification of -55083 (JP-A-63-222965). This type of device is generally configured to include an electromagnetic hydraulic pressure control device that controls the hydraulic pressure of a hydraulic pressure source to a predetermined height by controlling the exciting current of a solenoid. This is performed by solenoid control means such as a solenoid drive circuit.

However, it is said that electrical parts such as solenoids and solenoid control means are generally less reliable than mechanical parts. In a brake fluid pressure control device including an electromagnetic fluid pressure control device, when the solenoid or the like fails, the control of the fluid pressure of the brake cylinder that is the control target of the electromagnetic fluid pressure control device becomes defective or impossible, and the braking performance of the vehicle is reduced. There is a problem that it may become defective.

This problem also exists in the brake fluid pressure control device previously devised by the present inventor (hereinafter referred to as the previously devised device). This device (a) controls the hydraulic pressure of the first brake cylinder corresponding to either one of the front wheels and the rear wheels (hereinafter referred to as the first wheel) of the vehicle by the operation amount of the operation member, the operation amount of the operation stroke, or the like. When the first brake cylinder hydraulic pressure control device controls the hydraulic pressure according to the above, and (b) the hydraulic pressure of the hydraulic pressure source falls into the locked state based on the hydraulic pressure of the first brake cylinder. Is controlled to a height at which the rear wheels fall at the same time as or slightly later than the front wheels, and the second brake cylinder corresponding to the other of the front wheels and the rear wheels (hereinafter referred to as the second wheel) through the liquid passage. In the device devised earlier, if the solenoid etc. of the electromagnetic hydraulic pressure control device fails, the electromagnetic hydraulic pressure control device will have a height corresponding to the brake operation. Unable to generate normal output fluid pressure It becomes the second brake is inoperable corresponding to the second brake cylinder, a problem that the braking ability of the vehicle as a whole is lowered.

Therefore, in order to solve this problem, the inventor first
A transmission switching device is provided in the state of being connected to the first brake cylinder hydraulic pressure control device in the middle of the fluid passage that connects the electromagnetic hydraulic pressure control device and the second brake cylinder. The output hydraulic pressure of the electromagnetic hydraulic pressure control device is always transmitted to the second brake cylinder, but when the electromagnetic hydraulic pressure control device fails, the output hydraulic pressure of the first brake cylinder hydraulic pressure control device is transmitted. Invented that. According to this invention, even if the electromagnetic hydraulic pressure control device fails, the first brake cylinder hydraulic pressure control device ensures the operation of the second brake corresponding to the second brake cylinder that is the control target of the electromagnetic hydraulic pressure control device. It is possible to obtain the effect that the reduction of the braking ability as a whole is prevented.

The inventor of the present invention also provides a slip detecting means for detecting the slip condition of the second wheel in order to make the above-mentioned invention device capable of anti-skid control for the second wheel. , The electromagnetic hydraulic pressure control device of the previously devised device controls the hydraulic pressure of the hydraulic pressure source to a height at which the slip is an appropriate amount when the slip detecting means detects an excessive slip, A brake fluid pressure control device (hereinafter referred to as a device to be devised later) designed to supply the second brake cylinder has been devised.

"Problems to be solved by the device" However, it was found that there is still room for improvement in the device to be invented after this. That is, it is usual to judge whether or not the electromagnetic hydraulic pressure control device is out of order by comparing the output hydraulic pressure of the electromagnetic hydraulic pressure control device with the reference value in the brake operation state. In the device devised in, the anti-skid control is performed on a road surface having a particularly low coefficient of friction, and when the output hydraulic pressure of the electromagnetic hydraulic pressure control device falls below the reference value, it is determined that the electromagnetic hydraulic pressure control device is out of order. It is determined that the output hydraulic pressure of the first brake cylinder hydraulic pressure control device is transmitted to the second brake cylinder and the anti-skid control is stopped even though the electromagnetic hydraulic pressure control device is normal.

"Means for Solving the Problems" The present invention has been made to solve the above-mentioned problems, and its gist is to provide a brake fluid pressure control device (a) the first brake cylinder fluid pressure control device. And (b) the slip detecting means, and (c) the hydraulic pressure of the hydraulic pressure source is usually controlled to a height according to the operation amount of the operating member, and the slip detecting means detects an excessive slip. In that case, an electromagnetic hydraulic pressure control device that controls the slip to an appropriate height and supplies it to the second brake cylinder corresponding to the other wheel through the liquid passage, and (d) in the middle of the liquid passage. Is connected to the first brake cylinder hydraulic pressure control device,
A first state in which the second brake cylinder is cut off from the first brake cylinder hydraulic pressure control device so as to communicate with the electromagnetic hydraulic pressure control device, and a state in which the second brake cylinder is cut off from the electromagnetic hydraulic pressure control device so as to communicate with the first brake cylinder hydraulic pressure control device A state-switching solenoid valve device capable of switching to the second state, and (e) the state-switching solenoid valve device is connected to the state-switching solenoid valve device, and normally, in the brake operating state, the height of the output hydraulic pressure of the electromagnetic hydraulic pressure control unit When the value is larger than the value, the state switching solenoid valve device is placed in the first state, and when it is less than the reference value, it is placed in the second state, and when excessive slip is detected, the state switching solenoid valve device is placed in the first state to the second state. And a switching control means for prohibiting switching to.

The first brake cylinder hydraulic pressure control device is not limited to a type that mechanically controls the hydraulic pressure of the brake cylinder, such as a master cylinder, but an electromagnetic control type that is similar to the electromagnetic hydraulic pressure control device. It may be one.

The hydraulic pressure source of the electromagnetic hydraulic pressure control device may be a dedicated hydraulic pressure source or the hydraulic pressure source of the first brake cylinder hydraulic pressure control device. Further, the electromagnetic hydraulic pressure control device is not limited to directly controlling the output hydraulic pressure thereof in accordance with the operation amount of the operating member,
What is controlled according to the output hydraulic pressure of the first brake cylinder hydraulic pressure control device that is controlled to a height according to the operation amount of the operating member, that is, the output hydraulic pressure of the electromagnetic hydraulic pressure control device is indirectly operated. It is also possible to control according to the operation amount of.

[Operation] In the brake fluid pressure control device according to the present invention, the electromagnetic fluid pressure control device normally operates and the output fluid pressure thereof is higher than the reference value in the brake operation state. In this case, the state switching electromagnetic valve device enters the first state in which the output hydraulic pressure of the electromagnetic hydraulic pressure control device is guided to the second brake cylinder, the electromagnetic hydraulic pressure control device malfunctions, and the output hydraulic pressure thereof falls below the reference value. If so, the second state is introduced in which the output hydraulic pressure of the first brake cylinder hydraulic pressure control device is guided to the second brake cylinder instead of the output hydraulic pressure of the electromagnetic hydraulic pressure control device. On the other hand, when an excessive slip is detected in the brake operation state, the state switching solenoid valve device changes from the first state to the second state even if the output hydraulic pressure of the electromagnetic hydraulic pressure control device becomes equal to or less than the reference value. It is prohibited to switch to.

[Advantage of the Invention] As described above, according to the present invention, even if the electromagnetic hydraulic pressure control device fails, the second control target is provided, as in the case where the transmission switching device is provided in the device of the above invention. The brake cylinder becomes operable, and the effect of suppressing a decrease in the braking ability of the vehicle as a whole is obtained.

Further, according to the present invention, even if the output hydraulic pressure of the electromagnetic hydraulic pressure control device falls below the reference value during the anti-skid control, the output hydraulic pressure of the first brake cylinder hydraulic pressure control device is triggered by this as a trigger. The situation in which the brakes are supplied to the two brake cylinders is avoided, and thereby, the effect that the anti-skid control is well performed even when the friction coefficient of the road surface is particularly low is also obtained.

[Embodiment] An embodiment in which the present invention is applied to a brake hydraulic pressure control device of a hydraulic brake device for a four-wheeled vehicle will be described in detail below with reference to the drawings.

Reference numeral 10 in FIG. 1 indicates a brake pedal as an operating member. The brake pedal 10 is connected to a tandem brake master cylinder 14 (hereinafter simply referred to as a master cylinder) via a hydraulic booster 12, and is connected to a first pressurizing chamber 15 and a second pressurizing chamber 16 of the master cylinder 14. The brake fluid pressures having the same height are generated in accordance with the operating force of the brake pedal 10. The front wheel cylinder 1 of the front wheel is provided in the first pressurizing chamber 15.
8 (corresponding to the first brake cylinder in the present invention)
Are connected by a front main liquid passage 20. The hydraulic booster 12 is well known and is not indispensable for understanding the present invention, and thus detailed description thereof will be omitted. The hydraulic booster 12 is connected to the accumulator 22 by the first accumulator passage 24, and is connected to the reservoir 26 and the first accumulator passage 24.
They are connected by a reservoir passage 28. In the present embodiment, the master cylinder 14 and the front main liquid passage 2
0 constitutes the first brake cylinder hydraulic pressure control device.

Reference numeral 30 indicates a spool type proportional electromagnetic hydraulic pressure control valve (hereinafter, simply referred to as a control valve). This is accumulator 2
2, the reservoir 26 and the rear wheel cylinder 32 of the rear wheel (corresponding to the second brake cylinder in the present invention) are connected by a second accumulator passage 34, a second reservoir passage 36 and a rear main liquid passage 38, respectively. The control valve 30 is similar to that described in Japanese Utility Model Application No. 61-170587 (Japanese Utility Model Application Laid-Open No. 63-175376), and the hydraulic pressure of the rear wheel cylinder 32 (hereinafter The rear hydraulic pressure) is controlled to a height corresponding to the magnitude of the exciting current.

A two-position valve 50 is provided in the middle of the rear main liquid passage 38 with a liquid passage 52.
Is provided in a state of being connected to the second pressurizing chamber 16 of the master cylinder 14. As a result, the rear main liquid passage 38 is divided into a control valve side passage 54 on the control valve 30 side and a wheel cylinder side passage 56 on the rear wheel cylinder 32 side. The two-position valve 50 is always in the first position (original position shown in the figure), that is, in the manually operated state where the wheel cylinder side passage 56 is shut off from the control valve side passage 54 to communicate with the liquid passage 52 (second state in the present invention). Corresponding to)
However, if the solenoid 58 is excited, the second position,
That is, the switching valve is switched to an electrically operated state (corresponding to the first state in the present invention) in which the wheel cylinder side passage 56 is blocked from the liquid passage 52 and communicated with the control valve side passage 54. That is, in this embodiment, the two-position valve 50 constitutes the state switching electromagnetic valve device of the present invention.

A proportioning valve 60 is provided in the middle of the liquid passage 52, and the proportioning valve 60 is provided in the second pressurizing chamber 16 of the master cylinder 14.
The brake hydraulic pressure is appropriately reduced and supplied to the two-position valve 50.

Reference numeral 92 represents a computer including a CPU, a ROM, a RAM, an input unit, an output unit and a bus. Computer 92
In the input section of, the depression sensor 94 that detects the depression of the brake pedal 10, the depression force sensor 96 that detects the depression force of the brake pedal 10, and the front that detects the hydraulic pressure of the front wheel cylinder 18 (hereinafter referred to as the front hydraulic pressure). The hydraulic pressure sensor 98 and the rear hydraulic pressure sensor 10 for detecting the hydraulic pressure of the rear wheel cylinder 32 (hereinafter referred to as the rear hydraulic pressure).
0, a rear wheel load sensor 102 that detects the load applied to the rear wheels, and a rotation sensor 10 that detects the rotation of the left and right front wheels.
4, 106 and rotation sensors 108, 110 for detecting the rotation of the left and right rear wheels are connected, while the first solenoid control circuit 124 and the second solenoid control circuit 12 are connected to the output section.
6, the 1st warning lamp 128 and the 2nd warning lamp 129 are connected. The computer 92 controls the rear hydraulic pressure to an appropriate height based on various input signals by executing a control program (a program represented by a flowchart in FIGS. 2 and 3) stored in the ROM. The two-position valve 50 is configured to control the proper position. The above control will be described in detail later.

The liquid in the reservoir 26 is pumped up by the pump 130 and stored in the accumulator 22 at a certain range of liquid pressure. The motor 132 that drives the pump 130 is connected to the output section of the computer 92 via the motor control circuit 134, and the pump 1 is driven according to the hydraulic pressure in the accumulator 22 detected by the accumulator hydraulic pressure sensor 136.
The drive state of 30 is controlled. That is, in this embodiment, the accumulator 22, the pump 130, etc. constitute the hydraulic pressure source (hereinafter referred to as the control valve hydraulic pressure source) in the present invention corresponding to the control valve 30, and the control valve hydraulic pressure source and the control valve are provided. 30,
Front hydraulic pressure sensor 98, rear hydraulic pressure sensor 100, first
The solenoid control circuit 124, the part that controls the control valve 30 of the computer 92, and the rear main liquid passage 38 constitute the electromagnetic hydraulic pressure control device of the present invention. A level switch 140 is attached to the reservoir 26,
The liquid level of the reservoir 26 is monitored by the computer 92.

Next, the operation will be described.

At the same time when the power is turned on, the computer 92 operates to execute the hydraulic pressure control program represented by the flowcharts of FIGS. 2 and 3. First, in step S1 of FIG. 2 (hereinafter, simply represented by S1; the same applies to the following steps), the initial flag of the CPU is reset, and S
At 2, a demagnetization command is issued to the two-position valve 50 to position it in the original position shown. In S3, a pressure reduction command is issued to the control valve 30 so that the rear hydraulic pressure becomes zero.
That is, the exciting current of the solenoid is controlled to such a value that the rear wheel cylinder 32 is blocked from the accumulator 22 and communicates with the reservoir 26. Then, in S4, it is determined whether or not the depression of the brake pedal 10 is detected by the depression sensor 94, the brake pedal 10 is operated, and the determination result is YES.
If so, the steps from S5 are executed to control the rear hydraulic pressure to an appropriate height. At the same time, a brake fluid pressure having a height corresponding to the depression force of the brake pedal 10 is generated in the first and second pressurizing chambers 15 and 16 of the master cylinder 14,
The brake fluid pressure in the first pressurizing chamber 15 is the front main fluid passage 20.
And is supplied to the front wheel cylinder 18. On the other hand, if the brake pedal 10 is not operated and the determination result in S4 is NO, the process returns to S1.

In S5, it is determined whether or not the initial flag is set. If the determination result is NO, that is, if S5 is executed for the first time during one continuous brake operation,
In S6, the signal representing the rear wheel load is fetched from the rear wheel load sensor 102, but in the case of YES, that is,
When the execution of S5 is the second time or later, the execution of S6 is bypassed. In this embodiment, the brake fluid pressure control corresponding to one continuous brake operation is performed based on the actual rear wheel load immediately after the start of the brake operation. After the initial flag is set in S7, S8
In step S9, a signal representing the pedaling force is taken in, and in step S9, a signal representing the front hydraulic pressure is taken in from the front hydraulic pressure sensor 98.

In S10, it is determined whether or not the front system, more accurately, the first pressurizing chamber 15, the front wheel cylinder 18, and the front main liquid passage 20 of the master cylinder 14 have failed. That is, it is determined whether or not the actual brake pedal force exceeds a value at which the front hydraulic pressure should be increased to 0.5 kg / cm ² , but the front hydraulic pressure is equal to or less than a constant value close to zero. Of. When the determination result is NO, that is, when the front system is normal, S11 and subsequent steps are executed, and when the determination result is YES, that is, when the front system is defective, S17 and subsequent steps are executed.

First, the case where the front system is normal will be described. After the failure flag of the CPU is reset in S11, an instruction to turn off the first warning lamp 128 is issued in S12. Then, in S13, a target value of the rear hydraulic pressure is calculated by executing a normal-time hydraulic pressure calculation program (not shown) in the ROM. The target value of the rear hydraulic pressure is slightly smaller than the ideal value of the rear hydraulic pressure corresponding to the front hydraulic pressure and the rear wheel load, as shown in the graph of FIG. When it falls, the rear wheel falls slightly behind the front wheel. In this embodiment, the ROM stores a calculation formula with variables of the front hydraulic pressure and the rear wheel load, and the target value of the rear hydraulic pressure is calculated by this calculation formula. It should be noted that FIG. 4 representatively shows two cases corresponding to the time of empty vehicle and the time of constant volume.

Then, in S14, a signal representing the current rear hydraulic pressure is fetched from the rear hydraulic pressure sensor 100, and in S15, the control amount of the rear hydraulic pressure to be controlled this time is calculated by subtracting the current value from the target value. In S16, the control valve 30 is controlled based on the calculated control amount. Although the two-position valve 50 is currently in the original position shown and the control valve 30 is cut off from the rear wheel cylinder 32, it is switched to the second position in S100 of FIG. The control valve 30 controls the rear hydraulic pressure to an appropriate height.

On the other hand, if the front system has failed, the failure flag is set in S17, and then the first warning lamp 128 is turned on in S18. The driver is told that the front system has failed. In S19, a target value of the rear hydraulic pressure is calculated by executing a failure hydraulic pressure calculation program (not shown) stored in the ROM. The ROM stores a formula for calculating the rear hydraulic pressure, which is a height that compensates for the decrease in the braking ability of the entire vehicle due to the front failure, with the brake pedal force and the rear wheel load as variables. Thus, the target value of the rear hydraulic pressure is calculated. Then, it returns to the execution of S14.

After that, in S100 of FIG. 3, an excitation command for instructing the excitation of the solenoid 58 is issued to the two-position valve 50, whereby the two-position valve 50 is switched to the second position (the right position in the drawing). The determination result of S4 in FIG. 2 is YE
At the same time as S, that is, at the same time as the braking operation is started, the timer of the CPU is started, and in S101, it is determined whether or not the measured time has reached a certain time. . If the determination result is YES,
In S102, the rear hydraulic pressure is detected, and in S103, it is determined whether or not the rear hydraulic pressure is larger than a predetermined constant value, and thus it is determined whether or not the electromagnetic hydraulic pressure control device is out of order. . In the present embodiment, the reference value for determining whether or not the electromagnetic hydraulic pressure control device is in failure is set to the predetermined constant value. on the other hand,
If the result of the determination in S101 is NO, that is, if the fixed time has not elapsed from the start of the brake operation, the execution of S102 and S103 is bypassed. This is because it takes time for the rear hydraulic pressure to rise sufficiently. In addition, without waiting for the determination result of the rear hydraulic pressure, S10
The reason why the two-position valve 50 is switched to the second position at 0, that is, the rear wheel cylinder 32 is switched to the electrically operated state in which the rear wheel cylinder 32 communicates with the control valve 30 will be described later. If the determination result in S103 is YES, that is, if the electromagnetic hydraulic pressure control device operates normally, S104 and subsequent steps are executed.

In S104, a command to turn off the second warning lamp 129 for notifying the failure of the rear system is issued, and it is determined in S105 whether the failure flag is set. If the determination result is NO, S106 and subsequent steps are executed, but if YES, the process returns to S4 in FIG. When the front system has failed, only the rear hydraulic pressure control suitable for the front failure is performed, and the anti-skid control after S106 is not performed.

In S106 of FIG. 3, each rotation sensor 104, 1
The current estimated vehicle speed is calculated based on the signals from 06, 108, and 110, and the deceleration of the left and right rear wheels is calculated. The larger of the two decelerations represents the deceleration of the rear wheels. In S107, it is determined whether or not the deceleration is larger than a preset determination value α, and it is determined whether or not an excessive slip occurs and anti-skid control needs to be performed. The judgment result is YE
If S, S108 and subsequent steps are executed, but if NO, the process returns to S4 in FIG. That is, in this embodiment,
The rotation sensors 104 to 110 are the third sensors of the computer 92.
The slip detecting means in the present invention is configured in cooperation with the part that executes S106 and S107 in the figure.

When excessive slip occurs on the rear wheels and, as a result, the determination result in S107 of FIG. 3 is YES,
In S108, a value lower than the estimated vehicle speed by a constant value ΔV is set as the reference speed v _{d of the} rear wheels, and in S109, a smaller value of the left and right rear wheels is set as v _r, and S
At 110, it is then determined whether the wheel speed v _r is less than the reference speed v _d . At this stage, normally, the determination result is YES, and it is determined that the rear hydraulic pressure needs to be reduced in order to eliminate the excessive slip.
After the current rear hydraulic pressure is stored in S11, S112
At, a pressure reduction command is issued to the control valve 30. This reduces the rear hydraulic pressure, reduces the amount of slip on the rear wheels,
Rear wheel speed is restored. Then, in S113, S
Similar to 108, the reference speed V _d corresponding to the current estimated vehicle speed
Is calculated, the current rear wheel speed v _r is detected in S114 as in S109, and S1 is calculated in S115.
Similar to 10, it is then determined whether the wheel speed v _r is smaller than the reference speed v _d . If the determination result is YES, it is determined that the rear hydraulic pressure needs to be continuously reduced and the process returns to S113. However, when the brake pedal 10 is already released, or when the vehicle is almost stopped. Is returned to S1 in FIG. 2 by S116.

The determination result in S115 of FIG. 3 is NO, that is,
When the current rear wheel speed v _r is equal to or higher than the reference speed v _d , the rear hydraulic pressure is restored to the value before the pressure reduction is started, and the slip ratio of the rear wheel is too small and the braking distance is extended. Is avoided. Specifically, the rear hydraulic pressure stored in S111 is set as a target value, and in S117, S118, and S119, S14, S15, and S in FIG.
The control valve 30 is controlled similarly to 16. After that, S12
At 0, it is determined whether the brake pedal 10 is released or the vehicle speed is almost stopped. If the determination result is YES, the process returns to the execution of S1 in FIG. Although completed, in the case of NO, the process returns to the execution of S108 in FIG. As long as the rear wheel speed v _r is equal to or higher than the reference speed v _d , S120, S108, S10
9 and S110 are repeated.

As described above, the actual rear wheel speed v _r is equal to the reference speed v
By controlling so as to approach _d , the slip ratio of the rear wheels can be maintained within an appropriate range.

On the other hand, if the determination result in S103 is NO, that is, if the electromagnetic hydraulic pressure control device is out of order, then in S121, 2
A demagnetization command is issued to the position valve 50, which causes the two-position valve 50 to return to the first position (original position shown). Then, after the second warning light 129 is turned on in S122, the depression of the brake pedal 10 is released in S123, and the process returns to the execution of S1 in FIG. That is, if it is determined that the rear system has once failed in one continuous brake operation, the two-position valve 50 is placed in the first position until the brake operation ends.

At this time, as shown in FIG. 1, the brake fluid in the second pressurizing chamber 16 of the master cylinder 14 is supplied to the rear wheel cylinder 32 via the two-position valve 50, etc. A situation in which the rear brake cannot be operated due to a failure, more precisely, a failure of the electromagnetic hydraulic pressure control device except the wheel cylinder side passage 56 is avoided. The hydraulic pressure in the second pressurizing chamber 16 is appropriately reduced by the proportioning valve 60 and supplied to the rear wheel cylinder 32. That is, even if the electro-hydraulic pressure control device other than the wheel cylinder side passage 56 fails, the rear wheels are designed to fall later than the front wheels in the event of a locked state, and vehicle stability during braking is improved. It has been secured.

The flow chart of this embodiment is simplified as shown in FIG. 5, focusing on the switching control of the two-position valve 50.

As is clear from this flowchart, the two-position valve 50
Since S200 is executed, the brake operation is not performed.
While the determination result in 201 is NO, it is in the first position. And the brake operation is done,
After the normal control of the rear hydraulic pressure is performed in S202, the two-position valve 50 is switched to the second position by executing S203. Then, in S204, it is determined whether or not the current rear hydraulic pressure has dropped below a certain value, that is, the rear hydraulic pressure failure determination is performed, and the determination result is YE.
S, that is, when it is estimated that the electromagnetic hydraulic pressure control device is out of order, the two-position valve 50 is switched to the first position in S205, that is, the brake fluid of the master cylinder 14 is guided to the rear wheel cylinder 32. And S2
While the two-position valve 50 is held at the first position until it is detected that the brake operation is released at 06, S
When the determination result of 204 is NO, that is, when it is estimated that the electromagnetic hydraulic pressure control device is normal, the two-position valve 50 is kept in the second position, and the two-position valve 50 is appropriately adjusted according to the slip condition of the rear wheels. Antiskid control is performed.

As described above, in this embodiment, the rear hydraulic pressure failure determination is performed before the slip detection of the rear wheel, and the rear hydraulic pressure determination is not performed based on the hydraulic pressure after the anti-skid control. Therefore, even if the rear hydraulic pressure drops to a value close to 0 as a result of the anti-skid control, it is estimated that the electromagnetic hydraulic pressure control device is out of order and the two-position valve 50 is switched to the first position. Absent.

As is clear from the above description, in this embodiment,
Second solenoid control circuit 126 and computer 92
The part that controls the two-position valve 50 constitutes the switching control means in the present invention.

In this embodiment, the following effects can also be obtained.

As a result of the failure of the rear wheel cylinder 32, the two-position valve 50 is set to the first position even when the rear hydraulic pressure falls below a certain value.
It is designed to be positioned. S1 in FIG.
It is determined that the two-position valve 50 is in the second position, that is, the rear wheel cylinder 32 is in communication with the control valve 30 by executing S100 before the current rear hydraulic pressure determination by 03. Rear wheel cylinder 3
It is also possible to detect the failure of No. 2, more precisely, the failure of the rear wheel cylinder 32 or the wheel cylinder side passage 56. Therefore, although the control valve 30 and the control valve hydraulic pressure sources such as the accumulator 22 and the pump 130 are normal, the hydraulic pressure of the control valve hydraulic pressure source cannot be increased due to the failure of the rear wheel cylinder 32 and the like. It is possible to obtain the effect that the above situation is avoided and the boosting action of the hydraulic booster 12 is secured.

Further, as a result of the determination that the electromagnetic hydraulic pressure control device or the like is out of order, the brake fluid of the master cylinder 14 is guided to the rear wheel cylinder 32 through the two-position valve 50 and the like, the two-position valve 50 and the liquid passage 52. When the proportioning valve 60, the rear wheel cylinder 32, or the wheel cylinder side passage 56 fails, the second pressurizing chamber 16 cannot be boosted, but the tandem master cylinder 14 causes the first pressurizing chamber 15 to move to the first pressurizing chamber 15. The pressure can be increased by shutting off the pressure chamber 16. Therefore, it is possible to avoid a situation in which both the rear brake and the front brake are inoperable due to a failure of the two-position valve 50 or the like.

Further, the two-position valve 50 in the present embodiment is configured so that the master cylinder 14 is not operated when the main power source of the vehicle fails or the solenoid 58 is disconnected and the solenoid 58 cannot be excited.
The original position is set so that the brake fluid is guided to the rear wheel cylinder 32. Therefore, even if the electromagnetic hydraulic pressure control device becomes inoperable due to the failure of the main power supply, it is ensured that the brake fluid of the master cylinder 14 is supplied to the rear wheel cylinder 32.

Although one embodiment of the present invention has been described in detail above, the switching control of the two-position valve 50 can be variously changed.

For example, the hydraulic pressure control and the switching control of the two-position valve 50 of the above-described embodiment can be changed to the control represented by the flowcharts in FIGS. 6 and 7. In this embodiment,
In S300 of the main program of FIG. 6, the two-position valve 50 is moved to the first position, and in S301, CP
The slip flag of U is reset, and it is determined in S302 whether the brake operation is performed. If the brake operation is not performed and the determination result is NO, the process returns to the execution of S300, but if the brake operation is performed and the determination result is YES, the two-position valve 50 is switched to the second position in S303, and the rear position is performed in S304. The normal hydraulic control of the hydraulic pressure similar to that in the above-described embodiment is performed. In S305, it is determined whether or not an excessive slip has occurred in the rear wheel. If the determination result is NO, the process returns to S302, but YE
In the case of S, it is determined that anti-skid control is necessary, and after the slip flag is set in S306, anti-skid control is performed in S307.
In S308, it is determined whether or not the brake operation has been released, or whether or not the vehicle speed is close to the stopped state. If YES, the process returns to execution of 300 and the anti-skid control ends, but NO In this case, the process returns to S307 and the anti-skid control is repeated.

During this period, the interrupt program shown in FIG. 7 is periodically executed. Simultaneously with the determination result of S302 in FIG. 6 being YES, the timer of the CPU starts timing, and the interrupt program of FIG. 7 is interrupted and executed in the main program at regular time intervals according to the time counting. That is, the execution of the main program is temporarily suspended, the interrupt program is executed, and after the execution of the interrupt program is completed, the execution of the main program is started again. The interrupt program determines that the rear hydraulic pressure failure determination (S400) is NO and, even if the determination result is YES, the determination whether the slip flag is set (S401) is YES. Execution ends. That is, the two-position valve 50 is controlled according to the command of the main program. However, when the rear hydraulic pressure failure determination is YES and the slip flag determination is NO, it is estimated that the electromagnetic hydraulic pressure control device or the like is out of order,
In S402, the two-position valve 50 is moved to the first position, the brake operation is continued, and the determination result in S403 is YE.
During S, the two-position valve 50 is held in that position. In this case, the execution of this program continues until the brake operation is released.

In this way, the two-position valve 50 will not be switched to the first position even if it is determined during the anti-skid control whether or not the electromagnetic hydraulic pressure control device or the like is out of order. That is, in this embodiment, S300 of FIG.
The part for storing S303 and S303 and the part for executing it, and the part for storing the program in FIG. 7 and the part for executing it constitute the switching control means in the present invention.

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 drawings]

FIG. 1 is a system diagram of a hydraulic brake device including a brake hydraulic pressure control device according to an embodiment of the present invention, and FIGS. 2 and 3 are flow charts showing a hydraulic pressure control program in the above embodiment. is there. FIG. 4 is a graph showing the relationship between the rear wheel load, the front wheel cylinder hydraulic pressure, and the rear wheel cylinder hydraulic pressure in the above embodiment. FIG. 5 is a flow chart in which the hydraulic pressure control program of the above-mentioned embodiment is rewritten centering on the switching control of the two-position valve. FIGS. 6 and 7 are flow charts showing a hydraulic pressure control program in an embodiment different from the above embodiment in the switching control of the two-position valve. 10: Brake pedal, 12: Hydraulic booster 14: Tandem type brake master cylinder 18: Front wheel cylinder 20: Front main fluid passage 22: Accumulator 30: Spool type proportional electromagnetic hydraulic pressure control valve 32: Rear wheel cylinder 50: 2 position Valve, 92: computer 108, 110: rotation sensor

Claims (1)

[Scope of utility model registration request] 1. A height of hydraulic pressure of a first brake cylinder corresponding to either one of a front wheel and a rear wheel of a vehicle is controlled to a height according to an operation amount of an operation member, an operation amount such as an operation stroke and the like. A first brake cylinder hydraulic pressure control device; a slip detecting means for detecting the slip condition of the other of the front wheel and the rear wheel; and a hydraulic pressure of a hydraulic pressure source, which is usually a height corresponding to an operation amount of the operating member. In addition, when the slip detecting means detects an excessive slip, the slip detecting means controls the height to a proper amount, and the slip is controlled to a second brake cylinder corresponding to the other wheel through a liquid passage. An electromagnetic fluid pressure control device for supplying the fluid, and a second brake cylinder provided in the middle of the fluid passage in a state of being connected to the first brake cylinder fluid pressure control device. State switching solenoid valve that can be switched between a first state in which it is shut off from the electromagnetic fluid pressure control device and communicates with the electromagnetic hydraulic pressure control device, and a second state in which it is shut off from the electromagnetic hydraulic pressure control device and communicates with the first brake cylinder hydraulic pressure control device. The device and the state switching solenoid valve device are connected to the state switching solenoid valve device in the first state when the output hydraulic pressure of the electromagnetic hydraulic pressure control device is higher than a reference value in a brake operating state. And a switching control means for prohibiting the switching of the state switching electromagnetic valve device from the first state to the second state when the excessive slip is detected when the value is equal to or less than the reference value. Brake fluid pressure control device.