JPH11124021A - Brake fluid pressure control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate an arbitrary pressure differential between the wheel cylinder and the master cylinder pressures, relating to a brake fluid pressure control device that generates a higher wheel cylinder pressure than the master cylinder pressure. SOLUTION: This control device has a master cut-off valve 28 installed in the route connecting a master cylinder 18 and wheel cylinders 48, 50. A pump 70 for supplying high pressure brake fluid is installed between the master cut-off valve 28 and the wheel cylinders 48, 50. When the wheel cylinder pressure is required to be higher than the master cylinder pressure, an inlet valve 72 is opened and the pump 70 is activated. The master cut-off valve 28 is duty- controlled based on the target pressure differential that should generate between the master cylinder and the wheel cylinder pressures.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a brake fluid pressure control device, and more particularly to a brake fluid pressure control device suitable as a device for generating a wheel cylinder pressure higher than a master cylinder pressure in a vehicle.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Laid-Open No.
As disclosed in No. 0, there is known a device that generates a wheel cylinder pressure higher than a master cylinder pressure when an emergency braking operation is performed by a driver. The emergency brake operation is performed when the driver requests that the braking force be quickly increased. According to the above-described conventional device, when the emergency braking operation is performed, the braking force can be quickly increased in response to the request.

[0003]

The functions realized by the above-described conventional apparatus include, for example, an on-off valve (hereinafter, referred to as a "master cut valve") disposed between a master cylinder and a wheel cylinder, and a master valve. A pump that discharges high-pressure brake fluid between the cut valve and the wheel cylinder,
The present invention can also be realized by a device including a relief valve disposed in parallel with the master cut valve and allowing only a flow from the wheel cylinder to the master cylinder.

That is, in the apparatus having the above-described configuration, when the master cut valve is opened, the master cylinder and the wheel cylinder can be brought into conduction. In this case, the wheel cylinder pressure can be controlled to the same hydraulic pressure as the master cylinder pressure. Further, in the apparatus having the above-described configuration, when the master cut valve is closed and the pump is operated, the wheel cylinder pressure is increased by the relief pressure of the relief valve to a higher hydraulic pressure than the master cylinder pressure. Can be controlled. Therefore, according to the device having the above-described configuration, the master cut valve is opened when the driver performs a normal brake operation, and the master cut valve is opened when the driver performs an emergency brake operation. By setting the valve in the closed state and operating the pump, the same function as the above-described conventional device can be realized.

[0005] In a vehicle, it may be appropriate to generate a differential pressure between the wheel cylinder pressure and the master cylinder pressure in accordance with the running state of the vehicle and the brake operation of the driver. However, in the device having the above-described configuration, the differential pressure between the wheel cylinder pressure and the master cylinder pressure is generated by the relief valve. In this case, it is not possible to make the differential pressure variable, that is, to satisfy the above requirement. In this regard, the device having the above-described configuration has room for improvement as a device for generating a wheel cylinder pressure higher than the master cylinder pressure.

The present invention has been made in view of the above points, and has as its object to provide a brake fluid pressure control device capable of generating an arbitrary pressure difference between a wheel cylinder pressure and a master cylinder pressure. Aim.

[0007]

The above object is achieved by the present invention.
And a high-pressure source that supplies a high-pressure brake fluid between the on-off valve and the wheel cylinder in the path, the on-off valve being provided in a path connecting the master cylinder and the wheel cylinder. In the brake hydraulic pressure control device, when a wheel cylinder pressure higher than the master cylinder pressure is required, the opening and closing of the opening and closing is performed based on a target differential pressure to be generated between the master cylinder pressure and the wheel cylinder pressure. This is achieved by a brake fluid pressure control device including on-off valve driving means for duty-controlling a valve.

In the present invention, when the on-off valve is closed, the wheel cylinder pressure rises to a higher fluid pressure than the master cylinder pressure using the high pressure source as the fluid pressure source. When the on-off valve is opened in a situation where the wheel cylinder pressure is higher than the master cylinder pressure, the wheel cylinder pressure decreases toward the master cylinder pressure. Therefore, when the duty of the on-off valve is controlled, the wheel cylinder pressure repeatedly rises and falls with the opening and closing operation of the on-off valve. At this time, the pressure difference between the wheel cylinder pressure and the master cylinder pressure is determined according to the ratio at which the on-off valve is kept open (or closed).
That is, it changes according to the duty ratio used for duty control of the on-off valve. In the present invention, the duty ratio is determined such that the differential pressure matches the target differential pressure.

[0009] The object of the present invention is as described in claim 2.
2. The brake fluid pressure control device according to claim 1, wherein a temperature detection unit that detects a temperature of the brake fluid pressure control device, and a first correction that corrects a duty ratio used for driving the on-off valve based on the temperature. And means for controlling the brake fluid pressure.

In the present invention, the viscosity of the brake fluid flowing through the on-off valve decreases as the temperature of the brake fluid pressure control device increases. The pressure difference between the wheel cylinder pressure and the master cylinder pressure becomes smaller as the viscosity of the brake fluid decreases. Therefore, the differential pressure between the wheel cylinder pressure and the master cylinder pressure tends to be smaller as the temperature of the device is higher. In the present invention, the duty ratio used for duty control of the on-off valve is corrected based on the temperature of the device so as to eliminate the above-described influence. For this reason, the differential pressure between the wheel cylinder pressure and the master cylinder pressure is
It is controlled to a value that exactly matches the target differential pressure without being affected by the temperature of the device.

[0011] The above object is as described in claim 3.
2. The brake fluid pressure control device according to claim 1, wherein a battery voltage detecting means for detecting an output voltage of a battery for supplying electric power to the on-off valve, and a duty ratio used for driving the on-off valve based on the output voltage. And a second correction means for correcting the pressure.

In the present invention, the on-off valve exhibits higher responsiveness as the output voltage of the battery becomes higher. When the on-off valve is duty-controlled, the differential pressure between the wheel cylinder pressure and the master cylinder pressure changes according to the responsiveness of the on-off valve. In the present invention, the duty ratio used for the duty control of the on-off valve is corrected based on the output voltage of the battery so as to eliminate the above-mentioned influence. For this reason, the differential pressure between the wheel cylinder pressure and the master cylinder pressure is controlled to a value that exactly matches the target differential pressure without being affected by the output voltage of the battery.

Further, the above object is achieved by a brake fluid pressure control device according to the first aspect of the present invention.
The high-pressure source includes a pump and a motor, a master pressure sensor that detects a master cylinder pressure, a motor load detection unit that detects a load of the motor, the master cylinder pressure, the target differential pressure, This is achieved by a brake fluid pressure control device including third correction means for correcting a duty ratio used for driving the on-off valve based on a load.

In the present invention, the hydraulic pressure appearing on the discharge side of the pump is guided to the wheel cylinder. A load corresponding to the hydraulic pressure appearing on the discharge side of the pump, that is, a load corresponding to the wheel cylinder pressure is applied to the motor. The wheel cylinder pressure should be controlled to a value obtained by adding the target differential pressure to the master cylinder pressure. Therefore, the load of the motor should be a value corresponding to the sum of the master cylinder pressure and the target differential pressure. In the present invention, the duty ratio used for duty control of the on-off valve is corrected so that the motor load satisfies the above condition. When the above control is performed, the wheel cylinder pressure accurately matches the sum of the master cylinder pressure and the target differential pressure. In this case, the differential pressure between the wheel cylinder pressure and the master cylinder pressure accurately matches the target differential pressure.

[0015]

FIG. 1 is a system configuration diagram of a part of a brake fluid pressure control device according to an embodiment of the present invention. The braking fluid pressure control device of the present embodiment includes a front right wheel FR and a rear left wheel R
L and a second system including a left front wheel FL and a right rear wheel RR. These two systems are substantially identical in configuration. Therefore, in the following description, only the configuration and operation of the first system will be described.

The brake fluid pressure control device of this embodiment is a brake fluid pressure control device for a diagonal pipe (X pipe). The brake hydraulic pressure control device is provided with an electronic control unit 10 (hereinafter referred to as “ECU
10 "). The brake fluid pressure control device includes a brake pedal 12. A brake switch 14 is provided near the brake pedal 12. The brake switch 14 outputs an ON signal when the brake pedal 12 is depressed. ECU10
Determines whether the brake pedal 12 is depressed based on the output signal of the brake switch 14.

The brake pedal 12 is connected to a vacuum booster 16. The vacuum booster 16
When the brake pedal 12 is depressed, an assist force Fa having a predetermined boosting ratio with respect to the brake depression force F is generated. The vacuum booster 16 has the master cylinder 1
8 is fixed. A first hydraulic chamber and a second hydraulic chamber are formed inside the master cylinder 18. In each of these hydraulic chambers, a master cylinder pressure corresponding to the resultant force of the brake pedaling force F and the assist force Fa is generated.

A reservoir tank 20 is provided above the master cylinder 18. The master cylinder 18 and the reservoir tank 20 are electrically connected only when the depression of the brake pedal 12 is released. A first hydraulic passage 22 and a second hydraulic passage 24 communicate with the first hydraulic chamber and the second hydraulic chamber of the master cylinder 18, respectively. The first hydraulic passage 22 communicates with a first hydraulic circuit. On the other hand, the second hydraulic passage 24 communicates with a second hydraulic circuit (not shown).

The first hydraulic pressure passage 22 has a master pressure sensor 2
6 are provided. The master pressure sensor 26 outputs an electric signal pMC corresponding to the internal pressure of the first hydraulic passage 22 (hereinafter, referred to as “master cylinder pressure PM _{/ C} ”). The output signal pMC of the master pressure sensor 26 is supplied to the ECU 10. The ECU 10 detects the master cylinder pressure PM _{/ C} based on the output signal pMC.

The first hydraulic passage 22 has a master cut valve 2
The high-pressure passage 30 communicates with the high-pressure passage 30. The master cut valve 28 is a two-position solenoid valve that maintains an open state in a normal state and is closed when a drive signal is supplied from the ECU 10. The master cut valve 28 has a relief valve 3
2 and the check valve 34 are arranged in parallel. The relief valve 32 is configured so that the hydraulic pressure on the high-pressure passage 30 side
This is a constant-pressure release valve that allows a flow of brake fluid from the high-pressure passage 30 toward the first hydraulic passage 22 when the pressure is higher than a predetermined relief pressure as compared with the hydraulic pressure on the side. On the other hand, the check valve 34 is a one-way valve that allows only the flow of the brake fluid from the first hydraulic pressure passage 22 toward the high-pressure passage 30. In this embodiment, the relief valve 3
Reference numeral 2 is provided to prevent the occurrence of a liquid pressure exceeding the pressure resistance of the high-pressure passage 30 inside the high-pressure passage 30.

The high pressure passage 30 communicates with control hydraulic pressure passages 40 and 42 via holding valves 36 and 38. Holding valve 3
Numerals 6 and 38 are two-position solenoid valves that maintain a valve open state in a normal state and are closed when a drive signal is supplied from the ECU 10. Check valves 44 and 46 are arranged in parallel with the holding valves 36 and 38, respectively. Check valve 44, 4
Reference numeral 6 denotes a one-way valve that allows only the flow of brake fluid from the control hydraulic pressure passages 40 and 42 toward the high-pressure passage 30.

The control hydraulic pressure passages 40 and 42 communicate with a wheel cylinder 48 of the left rear wheel RL and a wheel cylinder 50 of the right front wheel FR, respectively. The wheel cylinders 48 and 50 are connected to a low pressure passage 56 via pressure reducing valves 52 and 54, respectively. The pressure reducing valves 52 and 54 are two-position solenoid valves that maintain a closed state in a normal state and are opened when a drive signal is supplied from the ECU 10. The low pressure passage 56 communicates with an auxiliary reservoir 58. The auxiliary reservoir 58 has a piston 60 and a spring 62 therein. The auxiliary reservoir 58
By elastically deforming the spring 62, a predetermined amount of brake fluid can be stored therein.

A suction passage 66 communicates with the auxiliary reservoir 58 via a reservoir cut check valve 64. The suction passage 66 communicates with the suction side of the pump 70 via a check valve 68, and also communicates with the first hydraulic passage 2 via a suction valve 72.
It communicates with 2. The suction valve 72 is a two-position solenoid valve that maintains a closed state in a normal state and is opened when a drive signal is supplied from the EUC 10. The discharge side of the pump 70 includes a check valve 74, a filter 76, and an orifice 7.
8 and communicate with the high-pressure passage 30. A motor 80 is connected to the pump 70. The motor 80 is an ECU
The pump 70 is driven by being controlled to 10. When driven by the motor 80, the pump 70 sucks the brake fluid from the auxiliary reservoir 58 or the suction passage 66, and discharges the sucked brake fluid to the high-pressure passage 30 at a predetermined discharge pressure.

The brake fluid pressure control device has a battery 82. The positive terminal of the battery 82 is connected to the ECU 10. The ECU 10 detects a potential appearing at the positive terminal of the battery 82 as an output voltage of the battery 82 (hereinafter, referred to as “battery voltage V _BAT ”). The brake fluid pressure control device further includes a temperature sensor 84. The temperature sensor 84 outputs an electric signal _TMC corresponding to the temperature of the brake fluid pressure control device, more specifically, the temperature near the master cut valve 28. The output signal T _MC of the temperature sensor 84 is supplied to the ECU 10. The ECU 10 detects the temperature near the master cut valve 28 based on the output signal _TMC .

FIG. 2 is a block diagram showing the structure of a part of the ECU 10. As shown in FIG. As shown in FIG. 2, the ECU 10
The transistor 86 is provided. The collector terminal 88 of the transistor 86 is connected to the power supply terminal. The emitter terminal 90 of the transistor 86 is connected to the motor 80. A drive circuit 94 is connected to a base terminal 92 of the transistor 86. Drive circuit 94
Can supply a drive signal having an arbitrary duty ratio to the base terminal 92 of the transistor 86.

Inside the ECU 10, a transistor 86
An MT terminal 96 derived from the emitter terminal 90 is provided. The ECU 10 supplies a drive signal having a predetermined duty ratio DUTY to the transistor 86, and at that time, a potential appearing at the MT terminal 90 (hereinafter, “MT potential”).
), A motor load voltage V _MT described later is calculated.

FIG. 3 shows that the ECU 10 determines that the motor load voltage V _MT
4 is a time chart for explaining the operation when detecting the. Specifically, FIG. 3A shows the waveform of the drive signal supplied from the drive circuit 94 to the transistor 86, and FIG.
3B shows the waveform of the MT potential appearing at the MT terminal 96, and FIG. 3C shows the timing at which the ECU 10 takes in the MT potential as the motor load voltage _VMT .

As shown in FIG. 3A, the motor load voltage V _MT is supplied to the transistor 86 with a predetermined duty ratio DU.
It is detected under a situation where a rectangular drive signal having TY is supplied. When the transistor 86 is turned on in response to the above drive signal, the MT terminal 96 conducts with the power supply terminal.
In this case, a potential at the power supply voltage level is generated at the MT terminal 96. Hereinafter, this period is referred to as “+ B period”.

In response to the above drive signal, the transistor 86
Is turned off, the MT terminal 96 is disconnected from the power supply terminal. The motor 80 functions as a generator while rotating without receiving power supply from the outside. For this reason,
When the MT terminal 96 is disconnected from the power terminal while the motor 80 is rotating, a voltage generated by the power generation operation of the motor 80 is guided to the MT terminal 96. Hereinafter, this period is referred to as a “power generation period”.

While a drive signal having a predetermined duty ratio DUTY is supplied to the transistor 86, the + B period and the power generation period are repeated at the duty ratio DUTY. Therefore, as shown in FIG. 3B, in such a situation, the potential of the power supply voltage level and the potential generated by the power generation operation of the motor 80 repeatedly appear at the MT terminal 96 at a predetermined duty ratio DUTY.

As shown in FIG. 3 (C), the ECU 10
Motor load voltage V _MTMT as the basis of
Take in the potential. Then, for example, the ECU 10
By averaging the MT potential detected during the power generation period,
And the motor load voltage V corresponding to each power generation period_MTSeeking
Confuse. Thus, according to the ECU 10, the motor 80
When driven with a duty ratio of DUTY, during each power generation period
The voltage generated by the motor 80 to the motor load voltage V_MTage
Can be detected.

Next, the operation of the brake fluid pressure control device of this embodiment will be described. The ECU 10 normally turns off all control valves included in the brake fluid pressure control device. In this case, the state shown in FIG. 1 is realized in the brake fluid pressure control device. In the state shown in FIG. 1, the wheel cylinders 48 and 50 are in communication with the master cylinder 18. In this case, a wheel cylinder pressure equal to the master cylinder pressure is guided to the wheel cylinders 48 and 50. Therefore, according to the brake fluid pressure control device, it is possible to generate a braking force according to the brake operation amount in normal times.

The ECU 10 outputs the output signal p of the master pressure sensor 26 every time the driver performs a brake operation.
Based on the MC and its rate of change ΔpMC, the operation is intended to promptly increase the braking force (hereinafter referred to as “operation”).
It is determined whether or not “emergency brake operation” is performed. As a result of the determination, when it is determined that the emergency brake operation has been performed, the ECU 10 starts brake assist control (hereinafter, referred to as “BA control”).

The BA control is a control for quickly increasing the wheel cylinder pressure P _{W / C} when an emergency brake operation is performed by the driver. According to the brake fluid pressure control device of the present embodiment, for example, the master cut valve 28 is set to the closed state (ON state), the suction valve 72 is set to the open state (ON state), and the pump 70 is set to the operating state. By doing so, it is possible to generate a high hydraulic pressure in the high-pressure passage 30 as compared with the master cylinder pressure PM _{/ C.} Therefore, if the above processing is executed after the emergency brake operation is detected, the wheel cylinder pressure P _{W / C} of each wheel can be quickly increased;
That is, the requirement for the BA control can be satisfied. Hereinafter, the control for increasing the wheel cylinder pressure P _{W / C} by the above method is referred to as “simple BA control”.

However, the simple BA control is a control in which the wheel cylinder pressure P _{W / C} of each wheel is immediately increased to the maximum hydraulic pressure after the start of the control. For this reason,
Depending on the simplified BA control, even if the brake operation amount is increased or decreased by the driver after the emergency brake operation is performed,
The change cannot reflect the wheel cylinder pressure P _{W / C.} In this regard, the simplified BA control is not necessarily the optimal control in securing a good brake feeling during the execution of the control.

According to the brake fluid pressure control device shown in FIG. 1, the control is started by setting the relief pressure of the relief valve 32 to an appropriate value and then performing the same control as that of the simple BA control described above. After that, the increase or decrease in the brake operation amount can be reflected on the wheel cylinder pressure P _{W / C.} Hereinafter, this control is referred to as “operation amount-linked BA control”. Operation amount link B
When the A control is performed, the relief pressure of the relief valve 32 is set to a target differential pressure to be generated between the wheel cylinder pressure P _{W / C} and the master cylinder pressure P _{M / C} during the execution of the BA control. .

According to the above setting, the relief valve 32
After the operation amount interlocking BA control is started, the high pressure passage is maintained until the hydraulic pressure in the high pressure passage 30 exceeds the above-described relief pressure (that is, the target differential pressure) and becomes higher than the master cylinder pressure PM _{/ C.} The flow of brake fluid from 30 to the first hydraulic passage 22 is prevented. When the hydraulic pressure in the high-pressure passage 30 exceeds a value obtained by adding the above-described relief pressure to the master cylinder pressure PM _{/ C} , the flow of the brake fluid is permitted. In this case, the hydraulic pressure in the high-pressure passage 30 is controlled to the hydraulic pressure obtained by adding the above-described target differential pressure to the master cylinder pressure PM _{/ C} during the execution of the manipulated variable-linked BA control.

According to the manipulated variable-linked BA control, the high pressure passage 3
A hydraulic pressure of zero is introduced into the wheel cylinders 48, 50 of each wheel. Therefore, according to the manipulated variable-linked BA control, the wheel cylinder pressure P _{W / C} of each wheel can be controlled to a fluid pressure higher by the target differential pressure than the master cylinder pressure P _{M / C.} The master cylinder pressure P _{M / C} increases or decreases according to an increase or decrease of the brake operation amount. Therefore, according to the operation amount-linked BA control, when the brake operation amount is increased or decreased during the execution of the control, the change can be reflected on the wheel cylinder pressure P _{W / C.}

By the way, in a vehicle, it is desired to generate an arbitrary pressure difference between the wheel cylinder pressure P _{W / C} and the master cylinder pressure P _{M / C according} to the running state of the vehicle and the operation state of the driver. There are cases. However, in the above-described operation amount-linked BA control, the differential pressure generated between the wheel cylinder pressure P _{W / C} and the master cylinder pressure P _{M / C} is fixed to the relief pressure of the relief valve 32. For this reason, depending on the above-mentioned manipulated variable interlocking BA control, it is necessary to satisfy the demand for changing the differential pressure generated between the wheel cylinder pressure P _{W / C} and the master cylinder pressure P _{M / C} according to various situations. Can not.

In the brake fluid pressure control device shown in FIG. 1, when the suction valve 72 is opened (ON state), the pump 70 is operated, and the master cut valve 28 is opened and closed at an appropriate duty ratio Duty. , The master cylinder pressure P in the high-pressure passage 30 by a fluid pressure corresponding to the duty ratio Duty.
Higher hydraulic pressure can be generated compared to _{M / C.} In this case, by changing the duty ratio Duty, the differential pressure between the wheel cylinder pressure P _{W / C} and the master cylinder pressure P _{M / C} can be changed appropriately.

The braking hydraulic pressure control device of this embodiment uses the above-described method to control the wheel cylinder pressure P during the BA control.
It is characterized in that an appropriate differential pressure corresponding to various situations is generated between the _{W / C} and the master cylinder pressure PM _{/ C.} Hereinafter, with reference to FIG. 4 to FIG. 14, a characteristic part of the brake fluid pressure control device of the present embodiment will be described. FIG. 4 and FIG.
4 is a flowchart illustrating an example of a control routine executed by the ECU 10 to realize the above functions. This routine is a routine that is repeatedly started each time the processing is completed. When this routine is started, first, the process of step 100 is executed.

In step 100, it is determined whether or not the execution condition of the BA control is satisfied. This step 100
In this example, it is determined that the execution condition of the BA control is satisfied after the start condition of the BA control is satisfied and until the end condition is satisfied. If it is determined in step 100 that the execution condition of the BA control is not satisfied, the current routine is terminated without any further processing. On the other hand, when it is determined that the execution condition of the BA control is satisfied, the process of step 102 is executed next.

The condition for starting the BA control is satisfied when it is determined that the emergency braking operation has been performed based on the output signal pMC of the master pressure sensor 26 and the rate of change ΔpMC. The BA control end condition is satisfied when the brake operation is released or when the vehicle speed becomes sufficiently low. In step 102, the calculation of the basic duty Duty ₀ is performed. The basic Duty ₀ is a value on which the duty ratio Duty of the drive signal supplied to the master cut valve 28 is based. In the present embodiment, the target differential pressure to be generated between the wheel cylinder pressure P _{W / C} and the master cylinder pressure P _{M / C} during the execution of the BA control depends on the running state of the vehicle, the brake operation of the driver, and the like. It is set according to. The basic duty Duty ₀ is a duty ratio for generating the target differential pressure under a reference environment. The ECU 10 stores a map that defines the basic duty Duty _{0 in} relation to the running state of the vehicle, the driver's brake operation, and the like. In this step 102, basic Duty ₀ is calculated by referring to the map.

In step 104, the battery voltage V _BAT
Is read. In step 106, the temperature sensor 84
The output signal T _MC is read of. In step 108,
Based on the battery voltage V _BAT and the output signal T _MC, the correction factor K ₁ is calculated. FIG. 6 shows the master cut valve 28.
2 shows the relationship between the attractive force generated by the electromagnet incorporated in the battery and the battery voltage _VBAT . The electromagnet generates a larger attractive force as the supplied voltage is higher. For this reason, as shown in FIG. 6, the electromagnet built in the master cut valve 28 generates a larger attractive force as the battery voltage V _BAT is higher.

FIG. 7 shows the relationship between the ratio at which the master cut valve 28 is closed when the master cut valve 28 is driven at a predetermined duty ratio and the battery voltage _VBAT . The master cut valve 28 is closed with excellent responsiveness as the built-in electromagnet generates a large attractive force. Accordingly, the ratio at which the master cut valve 28 closes increases as the electromagnet generates a greater attractive force, that is, as the battery voltage V _BAT increases.

FIG. 8 shows the high pressure passage 30 during the execution of the BA control.
Hydraulic pressure P_CNTAnd master cylinder pressure P _{M / C}Occur between
Differential pressure (P_CNT−P_{M / C}) And the battery voltage V_BATWith
Show the relationship. In the brake fluid pressure control device of this embodiment, B
A differential pressure (P_CNT−P_{M / C})
The higher the closing ratio of the master cut valve 28, the higher the pressure.
Therefore, the differential pressure (P_CNT−P_{M / C}) Is shown in FIG.
The battery voltage V _BATThe higher the pressure, the larger
You.

As described above, this occurs during the execution of the BA control.
Differential pressure (P_CNT−P_{M / C}) Is the battery voltage V_BATImpact of
Receive. Therefore, the appropriate differential pressure is always
(P _CNT−P_{M / C}) To generate the battery power
Pressure V_BATIn order to eliminate the influence of
It is appropriate to correct the dynamic duty Duty. FIG.
Is the resistance value of the coil built in the master cut valve 28 and
Relationship with temperature of master cut valve 28 (shown by solid line in FIG. 9)
And the flow through the master cut valve 28
The relationship between the viscosity of the fluid and the temperature of the master cut valve 28.
(A relationship shown by a broken line in FIG. 9). As shown in FIG.
The resistance value of the coil depends on whether the master cut valve 28 is hot.
The larger the value. On the other hand, the viscosity of brake fluid
Is smaller as the master cut valve 28 is hotter.
You.

FIG. 10 shows the relationship between the ratio at which the master cut valve 28 is closed when the master cut valve 28 is driven at a predetermined duty ratio and the temperature of the master cut valve 28. The master cut valve 28 generates a larger attraction force as a larger amount of current flows through the built-in coil. The valve closing ratio of the master cut valve 28 increases as the suction force increases. The current flowing through the coil increases as the resistance value decreases. Therefore, the master cut valve 2
The valve closing ratio of 8 increases as the resistance value of the coil decreases, that is, as the temperature of the master cut valve 28 decreases.

FIG. 11 shows the relationship between the differential pressure (P _CNT −P _{M / C} ) generated during the execution of the BA control and the temperature of the master cut valve 28. Differential pressure (P) generated during execution of BA control
_CNT- P _{M / C} ) increases as the closing ratio of the master cut valve 28 increases. In addition, the differential pressure (P _CNT -P _{M / C} )
The higher the viscosity of the brake fluid, the higher the pressure. For this reason, in the system of the present embodiment, as shown in FIG. 11, the lower the temperature of the master cut valve 28, the greater the differential pressure (P) between the high-pressure passage 30 and the first hydraulic passage 22.
_CNT- PM _{/ C} ) occurs.

As described above, the pressure difference (P _CNT −P _{M / C} ) generated during the execution of the BA control is affected by the temperature of the master cut valve 28. Accordingly, in order to always generate an appropriate differential pressure (P _CNT −P _{M / C} ) during the execution of the BA control, the drive duty Duty of the master cut valve 28 is corrected so as to eliminate the influence of the temperature. That is appropriate. At step 108, the influence of the battery voltage V _BAT, and the correction factor K ₁ for eliminating the influence of the temperature of the master cut valve 28 is calculated. Correction coefficient K ₁ is "1.
This coefficient is used by multiplying the basic Duty ₀ with 0 ”as the center value. In the system of this embodiment, the larger the drive duty Duty, the larger the valve closing ratio of the master cut valve 28. if the coefficient K ₁ a large value as compared with 1.0, to increase the closing ratio of the master cut 28 valve, i.e., to correct differential pressure (P _CNT -P M / _C) in the increasing direction possible. Further, if a value smaller than the correction coefficient K ₁ to 1.0, lowering the closing ratio of the master cut 28 valve, i.e., the differential pressure (P _CNT -P
_{M / C} ) can be corrected in the decreasing direction.

As described above, in the system of the present embodiment, the higher the battery voltage V _BAT , the larger the differential pressure (P _CNT −P _{M / C} ) becomes (see FIG. 8). Therefore, the battery voltage V
If _BAT is high, as the differential pressure (P _CNT -P M / _C) is reduced, i.e., the closing ratio of the master cut valve 28 is necessary to determine the correction factor K ₁ so as to reduce.
Such requirements can be met by a small value of the correction factor K ₁ as the battery voltage V _BAT is high.

In the system of this embodiment, the lower the temperature of the master cut valve 28, the lower the differential pressure (P _CNT -P
_{M / C} ) is large (see FIG. 11). Therefore, when the temperature of the master cut valve 28 is low, the differential pressure (P
_CNT -P M / _C) so as to decrease, i.e., closed the ratio of the master cut valve 28 is necessary to determine the correction factor K ₁ so as to reduce. Such a demand is met by the master cut valve 28
It can be temperature satisfies by a small value of the correction factor K ₁ The more at low temperatures.

[0053] Figure 12 shows an example of a map that defines the value of the correction factor K ₁ in relation to the temperature and the battery voltage V _BAT of the master cut valve 28. The map shown in FIG. 12 is set so that the above two requirements are both satisfied. ECU10 is a step 108 calculates a correction coefficient K ₁ by referring to a map shown in FIG. 12. According to the above-mentioned process, the influence of the battery voltage V _BAT, and can obtain the correction factor K ₁ which can properly eliminate the influence of the temperature of the master cut valve 28.

In step 110, the drive duty Duty
Is changed to the current value, and then a predetermined time αmsec (for example, 1
00 msec) has elapsed. In the system of the present embodiment, when the drive duty Duty of the master cut valve 28 is changed, thereafter, the differential pressure (P _CNT −) between the hydraulic pressure P _{CNT in the} high pressure passage 30 and the master cylinder pressure P _{M / C.}
P _{M / C} ) changes to a value corresponding to the drive duty Duty. At this time, the wheel cylinder pressure P _{W / C} of each wheel converges to the hydraulic pressure obtained by adding the differential pressure (P _CNT −P _{M / C} ) to the master cylinder pressure P _{M / C.}

The predetermined time αmsec is a time required for the wheel cylinder pressure P _{W / C} of each wheel to converge to a hydraulic pressure corresponding to the drive duty Duty after the drive duty Duty is changed. Therefore, when it is determined in step 110 that the elapsed time after the change in the drive duty Duty has not reached αmsec, it can be determined that the wheel cylinder pressure P _{W / C of} each wheel has not yet converged to an appropriate value. . In this case, the process of step 112 is executed next.

In step 112, the drive duty Duty is calculated according to the following equation. After the process of step 112 is performed, the caster cut valve 28 is thereafter duty-driven so that the valve closing ratio matches the drive duty Duty. Note that K ₂ shown in the following equation is a feedback correction coefficient described later. The central value “1.0” is substituted for the feedback correction coefficient K ₂ by the initial processing.

Duty = Duty ₀ * K ₁ * K ₂ (1) In step 114, a process of opening the holding valves 36 and 38 of each wheel (off state) is executed. This step 1
When the process of No. 14 is executed, the high-pressure passage 30 and the wheel cylinders 48 and 50 of each wheel are brought into conduction. Step 1
In step 16, a process of turning on the motor 80 and opening the suction valve 72 (on state) is executed. When the processing of the present step 116 is executed, the wheel cylinders 48, 50 of each wheel pass from the pump 70 through the high-pressure passage 30.
Then, a hydraulic pressure _PCNT higher than the master cylinder pressure PM _{/ C} is led. When the process of step 116 ends, the current routine ends.

According to the above processing, the wheel cylinder pressure P _{W / C} of each wheel is reduced by the drive duty Du of the master cut valve 28.
The hydraulic pressure can be controlled according to ty. The drive duty Duty is set between the wheel cylinder pressure P _{W / C} and the master cylinder pressure P _{M / C} between the wheel cylinder pressure P _{W / C} and the master cylinder pressure P _{M / C} without being affected by the battery voltage V _BAT or the temperature of the master cut valve 28. Is set to a value that can generate a target differential pressure according to the brake operation of the above. Therefore, according to the above processing, when the driver performs an emergency braking operation, the wheel cylinder pressure P _{W / C} of each wheel can be controlled to an optimal hydraulic pressure according to various situations. .

In this routine, the above step 110
After the drive duty Duty is changed, a predetermined time αms
When it is determined that ec has elapsed, it can be determined that the wheel cylinder pressure P _{W / C of} each wheel has converged to a value corresponding to the drive duty Duty. In this case, step 1
Subsequent to 10, the process of step 118 is executed. In step 118, the output signal pMC of the hydraulic pressure sensor 26 is maintained at a constant value, or the output signal pMC
Is determined to be increasing. As a result, when the above condition is not satisfied, that is, when it is determined that pMC is decreasing, it can be determined that the driver has reduced the brake operation amount. In this case, hereafter, step 1
Steps 12 and after are executed. According to the above processing, when the driver decreases the brake operation amount, the change can be reflected on the wheel cylinder pressure P _{W / C.}

In this routine, the above-mentioned step 118 is executed.
If it is determined that the output signal pMC is held or increased, the process of step 120 shown in FIG. 5 is executed. The ECU 10 performs steps 120 to 138 shown in FIG.
By performing the processing of (1), the feedback correction coefficient K
Update ₂ to an appropriate value. In step 120, a process of setting the holding valves 36, 38 of each wheel to a closed state (on state) is executed. After the processing of step 120 is performed, the wheel cylinder pressure P _{W / C} of each wheel is maintained at a constant value until the calculation of the feedback correction coefficient K ₂ is completed. The process of step 120 is performed in a situation where the holding or increase of the output signal pMC is detected, that is, in a situation where the driver intends to keep or increase the braking force. Calculation of the feedback correction coefficient K ₂ is carried out in a very short time. Therefore, even if the wheel cylinder pressure P _{W / C} is maintained at a constant value in the process of calculating the feedback correction coefficient K ₂ ,
The feeling of the brake operation is not substantially impaired.

In step 122, the duty driving of the motor 80 is started. After the processing of step 122 is executed, the ECU 10 thereafter sets “0%” and “10%”.
Predetermined duty ratio DUTY excluding 0% "(for example, 50%)
, The motor 80 is duty-driven. In step 124, it is determined whether a predetermined time βmsec has elapsed since the start of the duty driving of the motor 80. as a result,
If it is determined that βmsec has not yet elapsed, the process of step 122 is executed again. On the other hand,
If it is determined that msec has elapsed, the process of step 126 is executed next.

At step 126, the motor load voltage V _MT detected at that time is stored as the load voltage convergence value V _D. As described above, the ECU 10 detects a potential appearing at the MT terminal 96 during the power generation period (a period during which the supply of power to the motor 80 is stopped in the process of duty driving) as the motor load voltage _VMT . According to the above processing,
After the start of the duty driving of the motor 80, the motor load voltage V _MT detected when β msec has elapsed is stored as the load voltage convergence value V _D.

FIG. 13 shows the relationship between the generated torque of the motor 80 (that is, the load on the motor 80) and the motor load voltage _VMT . When the motor 80 rotates in a state where power supply is stopped, a potential corresponding to the generated torque of the motor 80 is generated at the MT terminal 96. Therefore, the motor load voltage V _MT has a value corresponding to the load of the motor 80 as shown in FIG.

In this embodiment, the load of the motor 80 is
The value increases as the hydraulic pressure _PCNT in the high-pressure passage 30 increases.
Therefore, the motor load voltage V _MT increases as the hydraulic pressure P _CNT increases. Thus, in the system according to the present embodiment, the correlation is found in a hydraulic P _CNT motor load voltage V _MT and the high-pressure passage 30. Therefore, the motor load voltage V _MT can be grasped as a hydraulic P _CNT of the high-pressure passage 30.

During the period in which the processing of steps 120 to 126 is executed, the master cut valve 28 is duty-driven at the drive duty Duty set in the previous processing cycle. Therefore, in step 122, the motor 8
After the duty drive of 0 is started, the differential pressure (P _CNT −P) corresponding to the open / close valve ratio of the master cut valve 28 is set between the hydraulic pressure P _{CNT in} the high pressure passage 30 and the master cylinder pressure P _{M / C.
M / C} ) occurs. In this case, the hydraulic pressure P of the high-pressure passage 30
_CNT converges to a value obtained by adding the master cylinder pressure P _{M / C} to the differential pressure corresponding to the opening and closing valve the ratio of the master cut valve _{28 (P CNT -P M / C} ).

[0066] Figure 14 is a hydraulic pressure P _CNT of the high-pressure passage 30 is sufficiently low, and, in a situation where the master cut valve 28 is driven at a predetermined duty ratio, the duty drive of the motor 80 is started The motor load voltage V _MT
Shows the changes that appear in Under such circumstances, the high pressure passage 30
The hydraulic pressure _PCNT rises over time after the duty driving of the motor 80 is started, and eventually converges to an appropriate value. Hereinafter, this convergence value is referred to as a hydraulic pressure convergence value. At this time, the motor load voltage V _MT is, as shown in FIG.
_The convergence to an appropriate value follows the change of the _CNT .

[0067] predetermined time βmsec used in the above step 124, the time required for the fluid pressure P _{CN T} of the high-pressure passage 30 converges to an appropriate value, i.e., the motor load voltage V _MT converges to an appropriate value Is set to the time required.
Therefore, at the time when the process of step 126 is executed, it can be determined that the motor load voltage V _MT has converged to a value corresponding to the hydraulic pressure convergence value. Therefore, the above step 1
The load voltage convergence value V _D stored at 26 is
Can be grasped as a hydraulic pressure convergence value.

In step 128, the master pressure sensor 26
Output signal pMC is detected. In step 130,
Load voltage convergence value V_DUpper limit value THU and lower limit value THL
Is calculated. In the system of the present embodiment,
Hydraulic pressure convergence value, that is, load voltage convergence value V_DThe trout
Ta cylinder pressure P_{M / C}, And of the master cut valve 28
It is almost uniquely determined according to the drive duty Duty.
In the system of the present embodiment, the master cylinder
Pressure P_{M / C}And drive duty Duty
And the load voltage convergence value V_DValue (hereinafter, this
Is the load voltage target value V_D ^*)
Wear.

Further, in this embodiment, the master cylinder pressure P _{M / C} is set with the load voltage target value V _D ^* as the center value.
For the combination of the driving duty Duty, it is possible to set the allowable range of the load voltage convergence value V _D. EC
U10 sets the upper and lower limits of the allowable range to the upper limit T
It is stored as HU and lower limit value THL. In the above step 130, the output signal pMC of the hydraulic pressure sensor 26 and
Based on the drive duty Duty of the master cut valve 28, the corresponding upper limit value THU and lower limit value THL
Is calculated.

In step 132, the load voltage convergence value V _D
Is larger than the upper limit value THU. As a result, if it is determined that V _D > THU holds,
It can be determined that an excessive hydraulic pressure convergence value has occurred in the high-pressure passage 30. If an excessive hydraulic pressure convergence value occurs in the high-pressure passage 30, the wheel cylinders 4
An excessive wheel cylinder pressure P _{W / C} is generated at 8, 50.
Therefore, in this case, it is appropriate to correct the driving duty Duty of the master cut valve 28 as the hydraulic pressure P _CNT of the high-pressure passage 30 is reduced. If the above determination is made in step 132, the process of step 134 is executed next.

In step 134, the feedback correction coefficient K ₂ is updated to a value smaller by a predetermined value ΔK ₂ . When the process of step 134 is completed, the processes of step 112 and thereafter shown in FIG. 4 are executed. According to the above processing, the drive duty Duty of the master cut valve 28
Can be corrected to a small value, and the valve closing ratio of the master cut valve 28 can be reduced. The hydraulic pressure P _{CNT in the} high pressure passage 30 is
The lower the valve closing ratio of the master cut valve 28, the lower the pressure.
Therefore, according to the above-described processing, a state where an appropriate wheel cylinder pressure P _{W / C} can be generated by the BA control after an excessive hydraulic pressure convergence value is detected can be formed.

[0072] In the present routine in step 132, if the load voltage convergence value V _D is judged to be not greater than the upper limit THU is, the process of step 136 is performed.
In step 136, the load voltage convergence value V _D is the lower limit TH
It is determined whether it is smaller than L. As a result, V _D
If it is determined that <THL is established, the high pressure passage 30
It can be determined that an excessively low hydraulic pressure convergence value has occurred. If an excessively low hydraulic pressure convergence value occurs in the high-pressure passage 30, an excessively low wheel cylinder pressure P _{W / C} is generated in the wheel cylinders 48, 50 of each wheel during execution of the BA control. Therefore, in this case, it is appropriate to correct the driving duty Duty of the master cut valve 28 as the hydraulic pressure P _CNT of the high-pressure passage 30 is increased. If the above determination is made in step 136, the process of step 138 is executed next.

In step 138, the feedback correction coefficient K ₂ is updated to a value larger by a predetermined value ΔK ₂ . When the process of step 138 is completed, the processes of step 112 and thereafter shown in FIG. 4 are executed. According to the above processing, the drive duty Duty of the master cut valve 28
Can be corrected to a large value, and the valve closing ratio of the master cut valve 28 can be increased. The hydraulic pressure P _{CNT in the} high pressure passage 30 is
The higher the closing ratio of the master cut valve 28, the higher the pressure.
Therefore, according to the above-described processing, it is possible to form a state in which an appropriate wheel cylinder pressure P _{W / C} can be generated by the BA control after an excessively low hydraulic pressure convergence value is detected.

[0074] In this routine in step 136, if the load voltage convergence value V _D is judged to be not lower than the lower limit value THL, it can be determined that the proper fluid pressure convergence value in the high-pressure passage 30 has occurred . When an appropriate hydraulic pressure convergence value is generated in the high-pressure passage 30, an appropriate wheel cylinder pressure P _{W / C is applied} to the wheel cylinders 48, 50 of each wheel during the execution of the BA control.
Occurs. In this case, without changing the feedback correction coefficient K _2, thereafter, step 11 shown in FIG. 4
The second and subsequent processes are executed.

As described above, according to the brake fluid pressure control device of the present embodiment, the master cut valve 28 is duty-driven so that the high pressure passage 30 and the first fluid pressure passage 22 can be connected during the BA control. , An arbitrary pressure difference (P _CTL −P _{M / C} ) can be generated. Further, according to the brake fluid pressure control device of the present embodiment, by using the correction coefficient K ₁ and the feedback correction coefficient K ₂ of the drive duty Duty of the master cut valve 28, the differential pressure (P _CTL -P _{M / C} ) can be accurately controlled to the target differential pressure.

In the above embodiment, the feedback correction coefficient K ₂ is updated without considering the temperature of the motor 80. However, when the feedback correction coefficient K ₂ is updated, the temperature of the motor 80 is updated. It may be considered. That is, the resistance of the winding of the motor 80 increases as the temperature increases. Therefore, the torque generated by motor 80 in the process of repeating steps 122 and 124 becomes smaller as the temperature of motor 80 becomes higher.

The load voltage convergence value V _D becomes smaller as the generated torque of the motor 80 becomes smaller. Therefore, the motor 8
When 0 is a high temperature, the load voltage convergence value V _D shifts to a small value. When the motor 80 is at a low temperature,
Load voltage convergence value V _D is shifted to a larger value. In the present embodiment, by comparing the load voltage convergence value V _D and the upper limit value THU and the lower limit value THL, the master cut valve 28
It is determined that the drive duty Duty needs to be corrected. Therefore, when the load voltage convergence value V _D is shifted as described above, there is a possibility that the driving duty Duty is not feedback correction to a proper value.

According to the system of this embodiment, the motor 80
Detecting the temperature, the larger value the load voltage convergence value V _D when the temperature is high, also, that its temperature is corrected load voltage convergence value V _D to a small value in the case of low temperature, The influence of the temperature of the motor 80 described above can be eliminated. Therefore, when updating the feedback correction coefficient K _2, taking into account the temperature of the motor 80 may perform the above correction.

In the above embodiment, the drive duty Duty of the master cut valve 28 is
However, the present invention is not limited to this, and the drive duty Duty
May be substituted by the temperature around the master cut valve 28. That is, the master cut valve 28
However, if a brake actuator is configured with other solenoids, the temperature of the brake actuator,
When the master cut valve 28 is housed in an engine room, for example, the temperature in the engine room or the intake air temperature,
That temperature may be substituted.

In the above-described embodiment, the temperature as the basis of the correction is detected by using the temperature sensor 84. However, the method of detecting the temperature is not limited to this. For example, in the system of this embodiment, a temperature characteristic is recognized in the voltage drop between the emitter and the collector of the transistor 86 used for driving the motor 80. Therefore, in the system according to the present embodiment, the temperature serving as the basis for correction may be detected based on the amount of voltage drop.

Further, in the above embodiment, the relief valve 32 is arranged in parallel with the master cut valve 28. However, in the system of this embodiment, the master cut valve 2
Since the function as a relief valve can be realized by 8, the relief valve 32 does not necessarily have to be provided. Therefore, according to the present embodiment, in addition to the various advantages described above, an advantage that the relief valve 32 can be omitted can be obtained.

In the above embodiment, the master cut valve 28 is replaced with the “open / close valve” of the first embodiment.
0 corresponds to the “high pressure source” according to claim 1, and the ECU 10 uses the drive duty Duty calculated in step 112 when the BA control execution condition is satisfied. 2. The "opening / closing valve driving means" according to claim 1, wherein the on / off valve driving means 28 is driven by duty.
Has been realized.

Further, in the above embodiment, the temperature sensor 84 corresponds to the "temperature detecting means" of the second aspect, and the ECU 10 executes the processing of the above steps 108 and 112 so that The "first correction means" according to claim 2 is realized. In the above embodiment, the “battery voltage detecting means” according to the third embodiment is executed by the ECU 10 executing the processing in the step 104.
By executing the processing of (2), the “second
Correction means "are each realized.

Further, in the above embodiment, the ECU 1
5. The "motor load detecting means" according to claim 4, wherein 0 executes the processing of steps 122 to 126.
However, the "third correction means" according to claim 4 is realized by executing the processing of steps 128 to 138 and 112.

[0085]

As described above, according to the first aspect of the present invention, the pressure difference between the wheel cylinder pressure and the master cylinder pressure is generated equal to an arbitrary target pressure by controlling the duty of the on-off valve. be able to. According to the second aspect of the present invention, a differential pressure equal to the target differential pressure can be accurately generated between the wheel cylinder pressure and the master cylinder pressure without being affected by the temperature of the device.

According to the third aspect of the present invention, a differential pressure equal to the target differential pressure can be accurately generated between the wheel cylinder pressure and the master cylinder pressure without being affected by the output voltage of the battery. . According to the fourth aspect of the present invention, the difference between the wheel cylinder pressure and the master cylinder pressure is corrected by correcting the duty ratio used for duty control of the on-off valve so that the motor load becomes an appropriate value. The pressure can be made to exactly match the target differential pressure.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a brake fluid pressure control device according to an embodiment of the present invention.

FIG. 2 is a block diagram of a part of the electronic control unit shown in FIG.

FIG. 3 is a time chart for explaining a method in which the electronic control unit shown in FIG. 1 detects a motor load voltage _VMT .

FIG. 4 is a flowchart (part 1) of an example of a control routine executed in the brake fluid pressure control device of the present embodiment.

FIG. 5 is a flowchart (part 2) of an example of a control routine executed in the brake fluid pressure control device of the present embodiment.

6 is a diagram showing a relationship between an attractive force of an electromagnet incorporated in the master cut valve shown in FIG. 1 and a battery voltage _VBAT .

7 is a diagram showing a relationship between a ratio at which the master cut valve shown in FIG. 1 is maintained in a closed state and a battery voltage V _BAT when the master cut valve is duty-driven.

FIG. 8 shows a differential pressure (P _CTL −P _{M / C} ) generated between the wheel cylinder pressure P _{W / C} and the master cylinder pressure P _{M / C} and the battery voltage V _{BAT in} the brake fluid pressure control device of the present embodiment. FIG.

FIG. 9 is a diagram showing a relationship between a resistance value of a coil built in the master cut valve shown in FIG. 1 and a temperature, and a relationship between viscosity and temperature of brake fluid flowing through the master cut valve.

10 is a diagram showing a relationship between a temperature and a ratio at which the master cut valve shown in FIG. 1 is maintained in a closed state when the master cut valve is duty-driven.

FIG. 11 shows a relationship between a pressure difference (P _CTL −P _{M / C} ) generated between a wheel cylinder pressure P _{W / C} and a master cylinder pressure P _{M / C} and a temperature in the brake fluid pressure control device of the present embodiment. FIG.

12 is an example of a map referred to when obtaining a correction factor K ₁ in the brake fluid pressure control device of the present embodiment.

FIG. 13 shows the motor load and the motor load voltage V shown in FIG.
FIG. 4 is a diagram illustrating a relationship with _MT .

14 is a diagram illustrating a change that occurs in a motor load voltage _VMT after the duty driving of the motor illustrated in FIG. 1 is started.

[Explanation of symbols]

 Reference Signs List 10 electronic control unit (ECU) 22 first hydraulic pressure passage 26 master pressure sensor 28 master cut valve 30 high pressure passage 36, 38 holding valve 70 pump 72 suction valve 80 motor 82 battery 84 temperature sensor 86 transistor 96 MT terminal

Claims (4)

[Claims] 1. An on-off valve disposed on a path connecting a master cylinder and a wheel cylinder, and a high-pressure source for supplying high-pressure brake fluid between the on-off valve and the wheel cylinder on the path. In the brake fluid pressure control device, when a wheel cylinder pressure higher than the master cylinder pressure is required, the opening / closing is performed based on a target differential pressure to be generated between the master cylinder pressure and the wheel cylinder pressure. A brake fluid pressure control device comprising an on-off valve driving means for duty-controlling a valve. 2. The brake fluid pressure control device according to claim 1, wherein a temperature detection means for detecting a temperature of the brake fluid pressure control device, and a duty ratio used for driving the on-off valve is corrected based on the temperature. And a first correcting unit that performs the control. 3. The brake fluid pressure control device according to claim 1, wherein a battery voltage detecting means for detecting an output voltage of a battery for supplying electric power to the on-off valve, and a duty ratio used for driving the on-off valve, And a second correcting means for correcting based on the output voltage. 4. The brake fluid pressure control device according to claim 1, wherein the high-pressure source includes a pump and a motor, a master pressure sensor that detects a master cylinder pressure, and a motor load detection unit that detects a load of the motor. And a third correction means for correcting a duty ratio used for driving the on-off valve based on the master cylinder pressure, the target differential pressure, and a load on the motor. apparatus.