JP2013166403A - Brake control apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a brake control apparatus configured to detect a pressure of a wheel cylinder on the high-pressure side, of the wheel cylinders in the same system, in more scenes.SOLUTION: A brake control apparatus includes: first solenoid in valves 16FL, 16FR provided in first wheel cylinder circuits 12FL, 12FR; second solenoid in valves 30FL, 30FR provided in series with the first solenoid in valves 16FL, 16Fr; third solenoid in valves 16RL, 16RR provided in second wheel cylinder circuits 12RL, 12RR; second pressure sensors 33FL, 33FR provided between the first solenoid in valves 16FL, 16FR and the second solenoid in valves 30FL, 30FR; and a brake control unit BCU that drives a pump P and the solenoid in valves to control a hydraulic pressure in the wheel cylinders, and receives a hydraulic pressure in the circuit detected by the second pressure sensors 33FL, 33FR.

Description

  The present invention relates to a brake control device.

  As a conventional brake control device, a hydraulic pressure control device having an X piping type brake piping system is provided with a circuit for connecting a wheel cylinder for the left rear wheel and a wheel cylinder for the right rear wheel, and a pressure sensor is provided on this circuit What is installed is known. Solenoid valves are provided on the left and right sides of the pressure sensor, respectively, and the detection target of the pressure sensor can be switched between the two brake piping systems by switching the open / close state of both solenoid valves.

JP 2009-298379 A

However, in the above prior art, when the control is performed to make the wheel cylinder pressures of the front and rear wheels different, the wheel cylinder pressure of the front wheels cannot be detected. For this reason, for example, in a scene in which only the wheel cylinder pressure of the front wheel is controlled to be pump-enhanced, there has been a problem that the wheel cylinder pressure on the high pressure side, which is important for control, cannot be detected.
An object of the present invention is to provide a brake control device capable of detecting the pressure of a high-pressure side wheel cylinder among wheel cylinders of the same system in more scenes.

  In the brake control device of the present invention, the first solenoid-in valve and the second solenoid-in valve are provided in series in the first brake circuit that connects between the master cylinder and the first wheel cylinder, and between the solenoid-in valves. A pressure sensor was installed.

  Therefore, the brake control device of the present invention can detect the pressure of the high-pressure side wheel cylinder in the same system of wheel cylinders in more scenes.

1 is a system configuration diagram illustrating a vehicle braking system to which a brake control device according to a first embodiment is applied. It is a circuit block diagram of the brake control apparatus of Example 1. FIG. 4 is a hydraulic circuit diagram showing a flow of brake fluid during normal braking (non-control state, front wheel pressure = rear wheel pressure = M / C pressure). It is a time chart at the time of normal braking (non-control state, front wheel pressure = rear wheel pressure = M / C pressure). FIG. 4 is a hydraulic circuit diagram showing a flow of brake fluid during normal braking (front wheel pressure increasing operation, rear wheel pressure increasing operation, M / C pressure> front wheel pressure, M / C pressure> rear wheel pressure). It is a time chart at the time of normal braking (front wheel pressure increasing operation, rear wheel pressure increasing operation, M / C pressure> front wheel pressure, M / C pressure> rear wheel pressure). FIG. 5 is a hydraulic circuit diagram showing a flow of brake fluid during normal braking (front wheel pressure increasing operation, rear wheel holding operation, front wheel pressure = M / C pressure, rear wheel pressure <M / C pressure). It is a time chart at the time of normal braking (front wheel pressure increasing operation, rear wheel holding operation, front wheel pressure = M / C pressure, rear wheel pressure <M / C pressure). FIG. 5 is a hydraulic circuit diagram showing the flow of brake fluid during normal braking (front wheel pressure increasing operation, rear wheel holding operation, front wheel pressure <M / C pressure, rear wheel pressure <M / C pressure). 4 is a time chart for normal braking (front wheel pressure increasing operation, rear wheel holding operation, front wheel pressure <M / C pressure, rear wheel pressure <M / C pressure). FIG. 6 is a hydraulic circuit diagram showing a flow of brake fluid during normal braking (front wheel pressure increasing operation, rear wheel pressure reducing operation, front wheel pressure = M / C pressure, rear wheel pressure <M / C pressure). It is a time chart at the time of normal braking (front wheel pressure increasing operation, rear wheel pressure reducing operation, front wheel pressure = M / C pressure, rear wheel pressure <M / C pressure). FIG. 5 is a hydraulic circuit diagram showing the flow of brake fluid during normal braking (front wheel pressure increasing operation, rear wheel pressure reducing operation, front wheel pressure <M / C pressure, rear wheel pressure <M / C pressure). It is a time chart at the time of normal braking (front wheel pressure increasing operation, rear wheel pressure reducing operation, front wheel pressure <M / C pressure, rear wheel pressure <M / C pressure). FIG. 4 is a hydraulic circuit diagram showing a flow of brake fluid during normal braking (front wheel holding operation, rear wheel pressure increasing operation, front wheel pressure <M / C pressure, rear wheel pressure = M / C pressure). It is a time chart at the time of normal braking (front wheel holding operation, rear wheel pressure increasing operation, front wheel pressure <M / C pressure, rear wheel pressure = M / C pressure). FIG. 5 is a hydraulic circuit diagram showing the flow of brake fluid during normal braking (front wheel holding operation, rear wheel pressure increasing operation, front wheel pressure <M / C pressure, rear wheel pressure <M / C pressure). It is a time chart at the time of normal braking (front wheel holding operation, rear wheel pressure increasing operation, front wheel pressure <M / C pressure, rear wheel pressure <M / C pressure). FIG. 5 is a hydraulic circuit diagram showing a flow of brake fluid during normal braking (front wheel holding operation, rear wheel holding operation, front wheel pressure <M / C pressure, rear wheel pressure <M / C pressure). It is a time chart at the time of normal braking (front wheel holding operation, rear wheel holding operation, front wheel pressure <M / C pressure, rear wheel pressure <M / C pressure). FIG. 5 is a hydraulic circuit diagram showing a flow of brake fluid during normal braking (front wheel holding operation, rear wheel pressure reducing operation, front wheel pressure <M / C pressure, rear wheel pressure <M / C pressure). It is a time chart at the time of normal braking (front wheel holding operation, rear wheel pressure reducing operation, front wheel pressure <M / C pressure, rear wheel pressure <M / C pressure). FIG. 5 is a hydraulic circuit diagram showing a flow of brake fluid during normal braking (front wheel pressure reducing operation, rear wheel pressure increasing operation, front wheel pressure <M / C pressure, rear wheel pressure = M / C pressure). It is a time chart at the time of normal braking (front wheel pressure reducing operation, rear wheel pressure increasing operation, front wheel pressure <M / C pressure, rear wheel pressure = M / C pressure). FIG. 5 is a hydraulic circuit diagram showing the flow of brake fluid during normal braking (front wheel pressure reducing operation, rear wheel pressure increasing operation, front wheel pressure <M / C pressure, rear wheel pressure <M / C pressure). It is a time chart at the time of normal braking (front wheel pressure reducing operation, rear wheel pressure increasing operation, front wheel pressure <M / C pressure, rear wheel pressure <M / C pressure). FIG. 5 is a hydraulic circuit diagram showing the flow of brake fluid during normal braking (front wheel pressure reducing operation, rear wheel holding operation, front wheel pressure <M / C pressure, rear wheel pressure <M / C pressure). 4 is a time chart for normal braking (front wheel pressure reducing operation, rear wheel holding operation, front wheel pressure <M / C pressure, rear wheel pressure <M / C pressure). FIG. 5 is a hydraulic circuit diagram showing the flow of brake fluid during normal braking (front wheel pressure reducing operation, rear wheel pressure reducing operation, front wheel pressure <M / C pressure, rear wheel pressure <M / C pressure). It is a time chart at the time of normal braking (front wheel pressure reducing operation, rear wheel pressure reducing operation, front wheel pressure <M / C pressure, rear wheel pressure <M / C pressure). FIG. 5 is a hydraulic circuit diagram showing a flow of brake fluid during pump control (front wheel pressure increasing operation, rear wheel pressure increasing operation, front wheel pressure = rear wheel pressure). It is a time chart at the time of pump control (front wheel pressure increasing operation, rear wheel pressure increasing operation, front wheel pressure = rear wheel pressure). FIG. 5 is a hydraulic circuit diagram illustrating a flow of brake fluid during pump control (front wheel pressure increasing operation, rear wheel pressure increasing operation, front wheel pressure> rear wheel pressure). It is a time chart at the time of pump control (front wheel pressure increasing operation, rear wheel pressure increasing operation, front wheel pressure> rear wheel pressure). FIG. 5 is a hydraulic circuit diagram showing a flow of brake fluid during pump control (front wheel pressure increasing operation, rear wheel pressure increasing operation, front wheel pressure <rear wheel pressure). It is a time chart at the time of pump control (front wheel pressure increasing operation, rear wheel pressure increasing operation, front wheel pressure <rear wheel pressure). FIG. 6 is a hydraulic circuit diagram showing a flow of brake fluid during pump control (front wheel pressure increasing operation, rear wheel holding operation, front wheel pressure ≧ rear wheel pressure). It is a time chart at the time of pump control (front wheel pressure increasing operation, rear wheel holding operation, front wheel pressure ≧ rear wheel pressure). FIG. 5 is a hydraulic circuit diagram showing a flow of brake fluid during pump control (front wheel pressure increasing operation, rear wheel holding operation, front wheel pressure <rear wheel pressure). It is a time chart at the time of pump control (front wheel pressure increasing operation, rear wheel holding operation, front wheel pressure <rear wheel pressure). FIG. 5 is a hydraulic circuit diagram showing a flow of brake fluid during pump control (front wheel pressure increasing operation, rear wheel pressure reducing operation, front wheel pressure ≧ rear wheel pressure). It is a time chart at the time of pump control (front wheel pressure increasing operation, rear wheel pressure reducing operation, front wheel pressure ≧ rear wheel pressure). FIG. 5 is a hydraulic circuit diagram showing a flow of brake fluid during pump control (front wheel pressure increasing operation, rear wheel pressure reducing operation, front wheel pressure <rear wheel pressure). It is a time chart at the time of pump control (front wheel pressure increasing operation, rear wheel pressure reducing operation, front wheel pressure <rear wheel pressure). FIG. 5 is a hydraulic circuit diagram showing a flow of brake fluid during pump control (front wheel holding, rear wheel pressure increase, front wheel pressure ≧ rear wheel pressure). It is a time chart at the time of pump control (front wheel holding, rear wheel pressure increase, front wheel pressure ≧ rear wheel pressure). FIG. 5 is a hydraulic circuit diagram showing a flow of brake fluid during pump control (front wheel holding, rear wheel pressure increase, front wheel pressure <rear wheel pressure). It is a time chart at the time of pump control (front wheel holding, rear wheel pressure increase, front wheel pressure <rear wheel pressure). FIG. 6 is a hydraulic circuit diagram showing a flow of brake fluid during pump control (front wheel holding, rear wheel holding, front wheel pressure = rear wheel pressure). It is a time chart at the time of pump control (front wheel holding, rear wheel holding, front wheel pressure = rear wheel pressure). FIG. 5 is a hydraulic circuit diagram showing a flow of brake fluid during pump control (front wheel holding, rear wheel holding, front wheel pressure> rear wheel pressure). It is a time chart at the time of pump control (front wheel holding, rear wheel holding, front wheel pressure> rear wheel pressure). FIG. 5 is a hydraulic circuit diagram showing a flow of brake fluid during pump control (front wheel holding, rear wheel holding, front wheel pressure <rear wheel pressure). It is a time chart at the time of pump control (front wheel holding, rear wheel holding, front wheel pressure <rear wheel pressure). FIG. 5 is a hydraulic circuit diagram showing a flow of brake fluid during pump control (front wheel holding, rear wheel pressure reduction, front wheel pressure ≧ rear wheel pressure). It is a time chart at the time of pump control (front wheel holding, rear wheel pressure reduction, front wheel pressure ≧ rear wheel pressure). FIG. 5 is a hydraulic circuit diagram showing a flow of brake fluid during pump control (front wheel holding, rear wheel pressure reduction, front wheel pressure <rear wheel pressure). It is a time chart at the time of pump control (front wheel holding, rear wheel pressure reduction, front wheel pressure <rear wheel pressure). FIG. 6 is a hydraulic circuit diagram showing a flow of brake fluid during pump control (front wheel pressure reduction, rear wheel pressure increase, front wheel pressure ≧ rear wheel pressure). It is a time chart at the time of pump control (front wheel pressure reduction, rear wheel pressure increase, front wheel pressure ≧ rear wheel pressure). FIG. 5 is a hydraulic circuit diagram showing a flow of brake fluid during pump control (front wheel pressure reduction, rear wheel pressure increase, front wheel pressure <rear wheel pressure). It is a time chart at the time of pump control (front wheel pressure reduction, rear wheel pressure increase, front wheel pressure <rear wheel pressure). FIG. 6 is a hydraulic circuit diagram showing a flow of brake fluid during pump control (front wheel pressure reduction, rear wheel pressure increase, front wheel pressure ≧ rear wheel pressure). It is a time chart at the time of pump control (front wheel pressure reduction, rear wheel pressure increase, front wheel pressure ≧ rear wheel pressure). FIG. 5 is a hydraulic circuit diagram showing a flow of brake fluid during pump control (front wheel pressure reduction, rear wheel holding, front wheel pressure <rear wheel pressure). It is a time chart at the time of pump control (front wheel pressure reduction, rear wheel holding, front wheel pressure <rear wheel pressure). FIG. 5 is a hydraulic circuit diagram showing a flow of brake fluid during pump control (front wheel pressure reduction, rear wheel pressure reduction, front wheel pressure ≧ rear wheel pressure). It is a time chart at the time of pump control (front wheel pressure reduction, rear wheel pressure reduction, front wheel pressure ≧ rear wheel pressure). FIG. 5 is a hydraulic circuit diagram showing a flow of brake fluid during pump control (front wheel pressure reduction, rear wheel pressure reduction, front wheel pressure <rear wheel pressure). It is a time chart at the time of pump control (front wheel pressure reduction, rear wheel pressure reduction, front wheel pressure <rear wheel pressure).

EMBODIMENT OF THE INVENTION Hereinafter, the form for implementing the brake control apparatus of this invention is demonstrated based on the Example shown on drawing.
[Example 1]
First, the configuration will be described.
FIG. 1 is a system configuration diagram showing a braking / driving system of a vehicle to which the brake control device of the first embodiment is applied, and FIG. 2 is a circuit configuration diagram of the brake control device of the first embodiment.
[System configuration]
The hydraulic pressure control unit HU is based on the friction braking force command from the brake control unit (controller) BCU. The wheel cylinder W / C (FL) for the left front wheel FL and the wheel cylinder W / C (RR) for the right rear wheel RR The respective hydraulic pressures of the wheel cylinder W / C (FR) of the right front wheel FR and the wheel cylinder W / C (RL) of the left rear wheel RL are increased or decreased or held.
The motor generator MG is a three-phase AC motor, which is connected via the rear drive shafts RDS (RL), RDS (RR) of the left and right rear wheels RL, RR and the differential gear DG, respectively, and receives commands from the motor control unit MCU. Based on this, power running or regenerative operation is performed, and driving force or regenerative braking force is applied to the rear wheels RL and RR.
The inverter INV performs the power running operation of the motor generator MG by converting the DC power of the battery BATT into AC power based on a drive command from the motor control unit MCU and supplying the AC power to the motor generator MG. On the other hand, based on a regenerative command from the motor control unit MCU, the AC power generated by the motor generator MG is converted into DC power and the battery BATT is charged to regenerate the motor generator MG.

The motor control unit MCU outputs a drive command to the inverter INV based on the drive force command from the drive controller 1. Also, based on the regenerative braking force command from the brake control unit BCU, the regenerative command is output to the inverter INV.
The motor control unit MCU sends the state of output control of the driving force or regenerative braking force by the motor generator MG and the maximum regenerative braking force that can be generated at present to the brake control unit BCU and drive controller 1 via the communication line 2. send. Here, the “maximum regenerative braking force that can be generated” is, for example, the battery SOC estimated from the voltage between terminals of the battery BATT and the current value, or the vehicle speed (vehicle speed) calculated (estimated) by the wheel speed sensor 3. Calculate from Further, when turning, the calculation is performed in consideration of the steering characteristic of the vehicle.
That is, at the time of full charge when the battery SOC is in the upper limit value or near the upper limit value, it is necessary to prevent overcharge from the viewpoint of battery protection. Further, when the vehicle speed decreases due to braking, the maximum regenerative braking force that can be generated by motor generator MG decreases. Furthermore, when regenerative braking is performed during high-speed traveling, the inverter INV becomes a high load, so the maximum regenerative braking force is limited even during high-speed traveling.

In addition, since the regenerative braking force is applied to the rear wheels in the vehicle of the first embodiment, if the regenerative braking force is excessive with respect to the friction braking force when turning, that is, the braking force of the rear wheel is too large with respect to the front wheels. The steer characteristic of the vehicle has a noticeable oversteer tendency and the turning behavior is disturbed. For this reason, when the oversteer tendency becomes strong, the maximum regenerative braking force is limited, and the front and rear wheel distribution of the braking force during turning is ideally distributed according to the vehicle specifications (for example, front: rear = 6: 4). ).
The drive controller 1 receives the accelerator opening from the accelerator opening sensor 4, the vehicle speed (vehicle speed) calculated by the wheel speed sensor 3, the battery SOC, and the like directly or via the communication line 2.
The drive controller 1 performs operation control of the engine ENG, operation control of an automatic transmission (not shown), and operation control of the motor generator MG by a driving force command to the motor control unit MCU based on information from each sensor. .

The brake control unit BCU has a brake fluid pressure P1 from the first pressure sensor 5, a brake pedal stroke amount from the brake pedal stroke sensor 6 (hereinafter also simply referred to as a stroke amount) S, directly or via the communication line 2. Steering angle sensor θ from steering angle sensor 7, wheel speeds V (FL), V (RR), V (FR), V (RL) from wheel speed sensor 3, yaw rate γ from yaw rate sensor 8, described later. The brake fluid pressure P2, the battery SOC, and the like from the second pressure sensors 33FL and 33FR are input.
The brake control unit BCU calculates the driver required braking force based on the brake pedal stroke amount S obtained from the brake pedal stroke sensor 6 and information from other sensors, and the calculated driver required braking force is applied to the regenerative braking force and the friction. The operation control of the hydraulic pressure control unit HU by the friction braking force command to the brake control unit BCU and the operation control of the motor generator MG by the regenerative braking force command to the motor control unit MCU are performed.
Here, in the first embodiment, as the regenerative cooperative control, the regenerative braking force is given priority over the friction braking force, and the maximum (maximum regenerative control) is used without using the hydraulic pressure as long as the driver requested braking force can be covered by the regenerative component. The area of regeneration is expanded to (power). Thereby, especially in a traveling pattern in which acceleration and deceleration are repeated, energy recovery efficiency is high, and energy recovery by regenerative braking is realized up to a lower vehicle speed. When the regenerative braking force is limited due to a decrease or increase in the vehicle speed during regenerative braking, the brake control unit BCU reduces the regenerative braking force and increases the friction braking force accordingly. Ensure braking force (driver required braking force). Hereinafter, reducing the regenerative braking force to increase the friction braking force is referred to as switching from the regenerative braking force to the friction braking force, and conversely reducing the friction braking force to increase the regenerative braking force. This is called switching from power to regenerative braking force.

The brake control unit BCU increases / decreases or maintains the wheel cylinder pressure based on the signal from each sensor, so that the braking force required for various vehicle controls including anti-lock brake control (hereinafter referred to as ABS control) can be achieved. Based on this, it is possible to execute automatic braking control, which is control for automatically increasing and decreasing the wheel cylinder pressure.
Here, the ABS control means that when it is detected that a wheel tends to be locked during a driver's braking operation, the wheel cylinder pressure is reduced or reduced in order to generate the maximum braking force while preventing the wheel from being locked. This control repeats holding and increasing pressure. In addition, in the above automatic braking control, when it is detected that an oversteer tendency or an understeer tendency has become strong at the time of turning of the vehicle, a vehicle behavior stability control for stabilizing the vehicle behavior by controlling the wheel cylinder pressure of a predetermined wheel to be controlled. In addition to the brake assist control (BAS) that generates higher pressure in the wheel cylinder W / C than the pressure actually generated in the master cylinder M / C when the driver operates the brake, the wheel cylinder pressure on the rear wheel is gradually increased. EBD control that brings the front-rear braking force distribution close to a predetermined ideal braking force distribution, and control that automatically generates a braking force according to the relative relationship with the preceding vehicle by auto-cruise control are included.

[Brake circuit configuration]
The hydraulic control unit HU according to the first embodiment has a piping structure called X piping that includes two systems of a P system and an S system. In addition, P attached to the end of the code | symbol of each site | part described in FIG. 2 shows P system, S shows S system, FL, RR, FR, and RL are a left front wheel, a right rear wheel, a right front wheel, and a left rear. Indicates that it corresponds to a ring. In the following description, the description of P, S or FL, RR, FR, RL is omitted when the P, S system or each wheel is not distinguished.
The hydraulic control unit HU according to the first embodiment uses a closed hydraulic circuit. Here, the closed hydraulic circuit is a hydraulic circuit that returns the brake fluid supplied to the wheel cylinder W / C to the reservoir tank RSV via the master cylinder M / C.
The brake pedal BP is connected to the master cylinder M / C via the input rod IR.
The P system has a wheel cylinder (first wheel cylinder) W / C (FR) for the right front wheel FR and a wheel cylinder (second wheel cylinder) W / C (RR) for the left rear wheel (second wheel cylinder) RL. Connected to the S system is a wheel cylinder (first wheel cylinder) W / C (FL) for the left front wheel FL and a wheel cylinder (second wheel cylinder) W / C (RR) for the right rear wheel RR. . The P system and the S system are provided with a pump PP and a pump PS. The pump PP and the pump PS are, for example, single gear pumps, driven by motors MP and MS, pressurize the brake fluid sucked from the suction side, and discharge it to the discharge side.
The master cylinder M / C and the wheel cylinder W / C are connected by a pipeline 11 and a pipeline 12. Pipe line 12P branches to pipe line (second wheel cylinder circuit) 12RL and pipe line (first wheel cylinder circuit) 12FR. Pipe line 12RL is connected to wheel cylinder W / C (RL). It is connected to the wheel cylinder W / C (FR). The pipe 12S branches into a pipe (first wheel cylinder circuit) 12FL) and a pipe (second wheel cylinder circuit) 12RR, and the pipe 12FL is connected to the wheel cylinder W / C (FL). Is connected to the wheel cylinder W / C (RR). The pipe 11 and the pipes 12P and 12S constitute a first brake circuit.

A gate-out valve 13 that is a normally open proportional solenoid valve is provided on the pipe line 11. A first pressure sensor 5 is provided at a position closer to the master cylinder M / C than the gate-out valve 13P of the P-system pipe line 11P. A pipe 14 is provided on the pipe 11 in parallel with the gate-out valve 13. A relief valve 15 is provided on the pipeline 14. The relief valve 15 is a one-way valve that allows the flow of brake fluid from the wheel cylinder W / C to the master cylinder M / C and prohibits the flow in the opposite direction, and its set pressure (valve opening pressure) Pr is The maximum regenerative braking force limit value (the upper limit value of the maximum regenerative braking force determined by the characteristics and capabilities of the motor generator MG and inverter INV) is used as the hydraulic pressure conversion value.
A solenoid-in valve 16 that is a normally open proportional solenoid valve corresponding to each wheel cylinder W / C is provided on the pipe 12. Among the solenoid-in valves 16, the solenoid-in valves 16FL and 16FR are first solenoid valves, and the solenoid-in valves 16RL and 16RR are third solenoid-in valves. Further, a pipe line 17 is provided on the pipe line 12 in parallel with the solenoid-in valve 16. A check valve 18 is provided on the pipe line 17. The check valve 18 allows the brake fluid to flow in the direction from the wheel cylinder W / C toward the master cylinder M / C, and prohibits the flow in the opposite direction.
A connection point between the pipeline 11 and the pipeline 12 and the discharge side of the pump P are connected by a pipeline 19. A discharge valve 20 of the pump P is provided on the pipe line 19. The discharge valve 20 allows the flow of brake fluid in the direction from the discharge side toward the pipe 11 and the pipe 12, and prohibits the flow in the opposite direction.
A position on the master cylinder M / C side with respect to the gate-out valve 13 of the pipeline 11 and the suction side of the pump P are connected by a pipeline 21 and a pipeline 22. On the pipeline 21, a gate-in valve 25, which is a normally closed proportional solenoid valve, is provided. A check valve 23 is provided on the pipeline 22. The check valve 23 allows the flow of brake fluid in the direction from the master cylinder M / C toward the suction side of the pump P, and prohibits the flow in the opposite direction.

A pipe line 24 is connected to a connection point between the pipe line 21 and the pipe line 22. A reservoir 34 is connected to the pipe line 24. A check valve 26 is provided on the pipe line 24. The check valve 26 allows the flow of brake fluid in the direction from the reservoir 34 toward the suction side of the pump P, and prohibits the flow in the opposite direction.
A position on the wheel cylinder W / C side of the conduit 12 from the solenoid-in valve 16 and the conduit 24 are connected by a conduit 27 and a conduit 28. On the conduit 27, a solenoid-out valve 29, which is a normally closed electromagnetic valve, is provided.
A solenoid that is a normally open solenoid valve between the solenoid-in valve (first solenoid-in valve) 16FL, 16FR on the pipes 12FL, 12FR and the wheel cylinders W / C (FL), W / C (FR) In valves (second solenoid in valves) 30FL and 30FR are provided. Pipe lines 31FL and 31FR are provided on the pipe lines 12FL and 12FR in parallel with the solenoid-in valves 30FL and 30FR. Check valves 32FL and 32FR are provided on the pipe lines 31FL and 31FR. The check valves 32FL and 32FR allow the brake fluid to flow in the direction from the wheel cylinder W / C to the master cylinder M / C and prohibit the flow in the opposite direction.
On the pipe lines 12FL and 12FR, second pressure sensors 33FL and 33FR are provided between the solenoid-in valves 16FL and 16FR and the solenoid-in valves 30FL and 30FR.
In the following description, the solenoid-in valves 16FL and 16FR are referred to as first solenoid-in valves, the solenoid-in valves 30FL and 30FR are referred to as second solenoid-in valves, and the solenoid-in valves 16RL and 16RR are referred to as third solenoid-in valves.
The brake control unit BCU has a gate-out valve 13, a gate-in valve 25, a first solenoid-in valve 16FL, 16FR, depending on the driver's requested braking force and the regenerative braking device (motor generator MG, inverter INV, battery BATT). The second solenoid-in valves 30FL and 30FR, the third solenoid-in valves 16RL and 16RR, the solenoid-out valve 29, and the motor M are actuated to control the brake fluid pressure of each wheel cylinder W / C.

Hereinafter, the operation of each valve and pump P of the hydraulic pressure control unit HU in each scene will be described based on the flow of brake fluid in the hydraulic circuit and a time chart. The solid line, the alternate long and short dash line, and the broken line in the hydraulic circuit mean the flow of brake fluid having different pressures. Although only the P system is illustrated in the hydraulic circuit, the same operation as that of the P system is performed for the S system, except when only one wheel cylinder pressure is increased or decreased, such as during ABS control intervention. In the time chart and the following description, “M / C pressure” is the master cylinder pressure, “front wheel pressure” is the wheel cylinder pressure of the front wheels FL and FR, and “rear wheel pressure” is the wheel cylinder pressure of the rear wheels RL and RR. The “first pressure sensor” is the first brake fluid pressure P1 detected by the first pressure sensor 5, the “second pressure sensor” is the second brake fluid pressure P2 detected by the second pressure sensor 33, “motor drive”. "Means the driving state of the motor M.
First, the function of each valve will be described.
The gate-out valve 13 is driven at the time of active control pressure increase (pressure increase by the pump P) to prevent the brake fluid from flowing into the M / C line (the pipelines 11 and 12). In addition, the brake fluid flows to the M / C line by driving at the time of depressurization of active control, and the pressure is reduced.
The gate-in valve 25 is driven when the pressure of active control is increased, and sucks brake fluid from the M / C line.
The first solenoid in valves 16FL and 16FR and the third solenoid in valves 16RL and 16RR are driven to maintain or reduce the wheel cylinder pressure during active control and passive control (control at the time of input from the brake pedal BP).
The second solenoid-in valves 30FL and 30FR are driven when only the front wheels or the rear wheels are controlled during the active control, and the wheels for detecting pressure are switched.
The solenoid-out valve 29 is driven during passive control and depressurizes the wheel cylinder by sending brake fluid from the wheel cylinder W / C to the reservoir 34.

[Normal braking]
・ Uncontrolled state, front wheel pressure = M / C pressure = rear wheel pressure Fig. 3 shows the flow of brake fluid during normal braking (uncontrolled state of each valve and pump P, M / C pressure = front wheel pressure = rear wheel pressure) FIG. 4 is a time chart.
Since the M / C pressure = the front wheel pressure = the rear wheel pressure, the valves and the pump P are not operated. In this case, the first brake fluid pressure P1 and the second brake fluid pressure P2 have the same value. Therefore, when there is a deviation between the sensor values of the first pressure sensor 5 and the second pressure sensor 33, the deviation amount can be corrected in the non-controlled state.
・ Front wheel pressure increase operation, rear wheel pressure increase operation, M / C pressure> front wheel pressure, M / C pressure> rear wheel pressure Figure 5 shows normal brake (front wheel pressure increase operation, rear wheel pressure increase operation, M / C pressure) (Front wheel pressure, M / C pressure> rear wheel pressure)). FIG. 6 is a time chart.
The first solenoid in valves 16FL and 16FR, the third solenoid in valves 16RL and 16RR, and the pump P are driven by PWM. That is, the front wheel pressure increasing operation is performed by the first solenoid-in valves 16FL and 16FR, and the rear wheel pressure increasing operation is performed by the third solenoid-in valves 16RL and 16RR.
In this case, the first brake fluid pressure P1 indicates the M / C pressure, and the second brake fluid pressure P2 indicates the front wheel pressure. The rear wheel pressure cannot be detected.
・ Front wheel pressure increasing operation, rear wheel holding operation, front wheel pressure = M / C pressure, rear wheel pressure <M / C pressure Figure 7 shows normal braking (front wheel pressure increasing operation, rear wheel holding operation, front wheel pressure = M / C FIG. 8 is a time chart showing the flow of brake fluid with pressure and rear wheel pressure <M / C pressure.
The third solenoid-in valves 16RL and 16RR are PWM driven. That is, the rear wheel holding operation is performed by the third solenoid-in valves 16RL and 16RR. The motor M is driven only in the holding operation after the ABS control pressure reducing operation, and is turned off otherwise.
In this case, the first brake fluid pressure P1 and the second brake fluid pressure P2 have the same value and indicate the front wheel pressure. The rear wheel pressure cannot be detected.

・ Front wheel pressure increasing operation, rear wheel holding operation, front wheel pressure <M / C pressure, rear wheel pressure <M / C pressure Figure 9 shows normal braking (front wheel pressure increasing operation, rear wheel holding operation, front wheel pressure <M / C Fig. 10 is a hydraulic circuit diagram showing the flow of brake fluid with pressure and rear wheel pressure <M / C pressure, and Fig. 10 is a time chart.
The first solenoid in valves 16FL and 16FR, the third solenoid in valves 16RL and 16RR, and the pump P are driven by PWM. That is, the front wheel pressure increasing operation is performed by the first solenoid-in valves 16FL and 16FR, and the rear wheel holding operation is performed by the third solenoid-in valves 16RL and 16RR.
In this case, the first brake fluid pressure P1 indicates the M / C pressure, and the second brake fluid pressure P2 indicates the front wheel pressure. The rear wheel pressure cannot be detected.
・ Front wheel pressure increase operation, rear wheel pressure decrease operation, front wheel pressure = M / C pressure, rear wheel pressure <M / C pressure FIG. 11 shows normal braking (front wheel pressure increase operation, rear wheel pressure decrease operation, front wheel pressure = M / C pressure) Pressure, rear wheel pressure <M / C pressure), a hydraulic circuit diagram showing the flow of brake fluid, and FIG. 12 is a time chart.
The third solenoid-in valves 16RL and 16RR and the pump P are PWM-driven, and the rear-wheel solenoid out valves 29RL and 29RR are ON-driven. That is, the front wheels are not controlled, and the pressure reduction operation of the rear wheels is performed by shutting off the M / C pressure by the third solenoid-in valves 16RL and 16RR and pressure reduction by the solenoid-out valves 29RL and 29RR. The motor M is driven to return the brake fluid temporarily stored in the reservoir 34 to the M / C line by the pressure reducing operation.
In this case, the first brake fluid pressure P1 and the second brake fluid pressure P2 have the same value and indicate the front wheel pressure. The rear wheel pressure cannot be detected.
・ Front wheel pressure increase operation, rear wheel pressure decrease operation, front wheel pressure <M / C pressure, rear wheel pressure <M / C pressure Figure 13 shows normal braking (front wheel pressure increase operation, rear wheel pressure decrease operation, front wheel pressure <M / C pressure) FIG. 14 is a hydraulic circuit diagram showing the flow of brake fluid with pressure, rear wheel pressure <M / C pressure, and FIG.
The first solenoid in valves 16FL and 16FR, the third solenoid in valves 16RL and 16RR and the pump P are PWM-controlled, and the rear wheel solenoid out valves 29RL and 29RR are driven ON. In other words, the pressure increase operation for the front wheel is performed by the first solenoid in valve 16FL, 16FR, and the pressure decrease operation for the rear wheel is performed by shutting off the M / C pressure by the third solenoid in valve 16RL, 16RR and by the solenoid out valve 29RL, 29RR. With reduced pressure. The motor M is driven to return the brake fluid temporarily stored in the reservoir 34 to the M / C line by the pressure reducing operation.
In this case, the first brake fluid pressure P1 indicates the M / C pressure, and the second brake fluid pressure P2 indicates the front wheel pressure. The rear wheel pressure cannot be detected.

-Front wheel holding operation, rear wheel pressure increasing operation, front wheel pressure <M / C pressure, rear wheel pressure = M / C pressure Figure 15 shows normal braking (front wheel holding operation, rear wheel pressure increasing operation, front wheel pressure <M / C pressure) Pressure, rear wheel pressure = M / C pressure) is a hydraulic circuit diagram showing the flow of brake fluid, and FIG. 16 is a time chart.
The first solenoid valves 16FL and 16FR are driven by PWM, and the pump P is turned OFF or PWM. That is, the rear wheels are not controlled, and the holding operation for the front wheels is performed by the first solenoid-in valves 16FL and 16FR. The motor M is driven only in the holding operation after the ABS control pressure reducing operation, and is turned off otherwise.
In this case, the first brake fluid pressure P1 indicates the M / C pressure, and the second brake fluid pressure P2 indicates the front wheel pressure. Since the rear wheel pressure is the same as the M / C pressure, it can be detected at P1.
-Front wheel holding operation, rear wheel pressure increasing operation, front wheel pressure <M / C pressure, rear wheel pressure <M / C pressure Figure 17 shows normal braking (front wheel holding operation, rear wheel pressure increasing operation, front wheel pressure <M / C pressure) Pressure, rear wheel pressure <M / C pressure), a hydraulic circuit diagram showing the flow of brake fluid, and FIG. 18 is a time chart.
The first solenoid in valves 16FL and 16FR and the third solenoid in valves 16RL and 16RR are PWM driven, and the pump P is turned OFF or PWM driven. That is, the front wheel holding operation is performed by the first solenoid-in valves 16FL and 16FR, and the rear wheel pressure increase control is performed by the third solenoid-in valves 16RL and 16RR. The motor M is driven only in the holding operation after the ABS control pressure reducing operation, and is turned off otherwise.
In this case, the first brake fluid pressure P1 indicates the M / C pressure, and the second brake fluid pressure P2 indicates the front wheel pressure. The rear wheel pressure cannot be detected.
・ Front wheel holding operation, rear wheel holding operation, front wheel pressure <M / C pressure, rear wheel pressure <M / C pressure Figure 19 shows normal braking (front wheel holding operation, rear wheel holding operation, front wheel pressure <M / C pressure, FIG. 20 is a time chart showing a hydraulic circuit diagram showing the flow of brake fluid with rear wheel pressure <M / C pressure.
The first solenoid in valves 16FL and 16FR and the third solenoid in valves 16RL and 16RR are PWM driven, and the pump P is turned OFF or PWM driven. That is, the front wheel holding operation is performed by the first solenoid-in valves 16FL and 16FR, and the rear wheel holding operation is performed by the third solenoid-in valves 16RL and 16RR. The motor M is driven only in the holding operation after the ABS control pressure reducing operation, and is turned off otherwise.
In this case, the first brake fluid pressure P1 indicates the M / C pressure, and the second brake fluid pressure P2 indicates the front wheel pressure. The rear wheel pressure cannot be detected.

-Front wheel holding operation, rear wheel pressure reducing operation, front wheel pressure <M / C pressure, rear wheel pressure <M / C pressure Figure 21 shows normal braking (front wheel holding operation, rear wheel pressure reducing operation, front wheel pressure <M / C pressure, FIG. 22 is a hydraulic circuit diagram showing the flow of brake fluid with rear wheel pressure <M / C pressure, and FIG. 22 is a time chart.
The first solenoid-in valves 16FL and 16FR, the third solenoid-in valves 16RL and 16RR and the pump P are PWM driven, and the rear-wheel solenoid out valves 29RL and 29RR are driven ON. That is, the front wheel holding operation is performed by the first solenoid-in valves 16RL and 16RR, and the rear wheel holding operation is performed by the third solenoid-in valves 16RL and 16RR.
In this case, the first brake fluid pressure P1 indicates the M / C pressure, and the second brake fluid pressure P2 indicates the front wheel pressure. The rear wheel pressure cannot be detected.
-Front wheel pressure reduction operation, rear wheel pressure increase operation, front wheel pressure <M / C pressure, rear wheel pressure = M / C pressure Figure 23 shows normal braking (front wheel pressure reduction operation, rear wheel pressure increase operation, front wheel pressure <M / C pressure) Pressure, rear wheel pressure = M / C pressure), a hydraulic circuit diagram showing the flow of brake fluid, and FIG. 24 is a time chart.
The first solenoid-in valves 16FL and 16FR and the pump P are driven by PWM, and the solenoid-out valves 29FL and 29FR on the front wheels are driven ON. That is, the front wheel pressure reduction operation is performed by blocking the M / C pressure by the first solenoid-in valves 16RL and 16RR and by pressure reduction by the solenoid-out valves 29FL and 29FR.
In this case, the first brake fluid pressure P1 indicates the M / C pressure, and the second brake fluid pressure P2 indicates the front wheel pressure. The rear wheel pressure cannot be detected.
・ Front wheel pressure reduction operation, rear wheel pressure increase operation, front wheel pressure <M / C pressure, rear wheel pressure <M / C pressure Figure 25 shows normal braking (front wheel pressure reduction operation, rear wheel pressure increase operation, front wheel pressure <M / C FIG. 26 is a time chart showing the flow of brake fluid with pressure and rear wheel pressure <M / C pressure.
The first solenoid-in valves 16FL, 16FR, the third solenoid-in valves 16RL, 16RR and the pump P are driven by PWM, and the solenoid-out valves 29FL, 29FR on the front wheels are driven ON. In other words, the pressure reduction operation for the front wheels is performed by blocking the M / C pressure with the first solenoid-in valves 16RL and 16RR and the pressure reduction with the solenoid-out valves 29FL and 29FR, and the pressure increase operation for the rear wheels is performed with the third solenoid-in valve 16RL. , 16RR is implemented. The motor M is driven to return the brake fluid temporarily stored in the reservoir 34 to the M / C line by the pressure reducing operation.
In this case, the first brake fluid pressure P1 indicates the M / C pressure, and the second brake fluid pressure P2 indicates the front wheel pressure. The rear wheel pressure cannot be detected.

-Front wheel pressure reducing operation, rear wheel holding operation, front wheel pressure <M / C pressure, rear wheel pressure <M / C pressure Figure 27 shows normal braking (front wheel pressure reducing operation, rear wheel holding operation, front wheel pressure <M / C pressure, FIG. 28 is a time chart showing a hydraulic circuit diagram showing a flow of brake fluid with rear wheel pressure <M / C pressure.
The first solenoid-in valves 16FL, 16FR, the third solenoid-in valves 16RL, 16RR and the pump P are driven by PWM, and the solenoid-out valves 29FL, 29FR on the front wheels are driven ON. That is, the front wheel pressure reduction operation is performed by shutting off the M / C pressure with the first solenoid in valves 16RL and 16RR and the pressure reduction with the solenoid out valves 29FL and 29FR, and the rear wheel holding operation is performed with the third solenoid in valve 16RL, Implemented by 16RR. The motor M is driven to return the brake fluid temporarily stored in the reservoir 34 to the M / C line by the pressure reducing operation.
In this case, the first brake fluid pressure P1 indicates the M / C pressure, and the second brake fluid pressure P2 indicates the front wheel pressure. The rear wheel pressure cannot be detected.
・ Front wheel pressure reduction operation, rear wheel pressure reduction operation, front wheel pressure <M / C pressure, rear wheel pressure <M / C pressure Figure 29 shows normal braking (front wheel pressure reduction operation, rear wheel pressure reduction operation, front wheel pressure <M / C pressure, FIG. 30 is a time chart showing a hydraulic circuit diagram showing the flow of brake fluid with rear wheel pressure <M / C pressure.
The first solenoid in valves 16FL, 16FR, the third solenoid in valves 16RL, 16RR and the pump P are PWM driven, and the solenoid out valves 29FL, 29FR, 29RL, 29RR are ON driven. That is, the front and rear wheels are depressurized by shutting off the M / C pressure with the solenoid valves 16FL, 16FR, 16RL, 16RR and depressurizing with the solenoid-out valves 29FL, 29FR, 29RL, 29RR. The motor M is driven to return the brake fluid temporarily stored in the reservoir 34 to the M / C line by the pressure reducing operation.
In this case, the first brake fluid pressure P1 indicates the M / C pressure, and the second brake fluid pressure P2 indicates the front wheel pressure. The rear wheel pressure cannot be detected.

[During pump control]
Front wheel pressure increase operation, rear wheel pressure increase operation, front wheel pressure = rear wheel pressure FIG. 31 shows the flow of brake fluid during pump control (front wheel pressure increase operation, rear wheel pressure increase operation, front wheel pressure = rear wheel pressure). Hydraulic circuit diagram, FIG. 32 is a time chart.
The gate-in valve 25, the gate-out valve 13 and the pump P are PWM driven. That is, when performing front-rear same-pressure control, the pressure increasing operation is performed by the number of rotations of the gate-in valve 25, the gate-out valve 13, and the motor M.
In this case, the first brake fluid pressure P1 indicates the M / C pressure, and the second brake fluid pressure P2 indicates the front and rear wheel pressure when the control is performed to the same pressure on the four wheels.
Front wheel pressure increase operation, rear wheel pressure increase operation, front wheel pressure> rear wheel pressure FIG. 33 shows the flow of brake fluid during pump control (front wheel pressure increase operation, rear wheel pressure increase operation, front wheel pressure> rear wheel pressure). Hydraulic circuit diagram, FIG. 34 is a time chart.
The gate-in valve 25, the gate-out valve 13, the third solenoid-in valves 16RL and 16RR, and the pump P are PWM driven. That is, the pressure increase operation of the front wheel on the high pressure side is performed by the rotation speed of the gate-in valve 25, the gate out valve 13, and the motor M, and the pressure increase operation of the rear wheel on the low pressure side is performed by the third solenoid in valves 16RL and 16RR. To implement. The rotation speeds of the gate-in valve 25 and the motor M are controlled in accordance with the front wheel pressure increasing operation and the rear wheel pressure increasing operation.
In this case, the first brake fluid pressure P1 indicates the M / C pressure, and the second brake fluid pressure P2 indicates the front wheel pressure having a high pressure. The rear wheel pressure cannot be detected.
Front wheel pressure increase operation, rear wheel pressure increase operation, front wheel pressure <rear wheel pressure FIG. 35 shows the flow of brake fluid during pump control (front wheel pressure increase operation, rear wheel pressure increase operation, front wheel pressure <rear wheel pressure). The hydraulic circuit diagram and FIG. 36 are time charts.
The gate-in valve 25, the gate-out valve 13 and the pump P are PWM-driven, and the second solenoid-in valves 30FL and 30FR are ON-driven. In other words, the pressure increase operation for the front wheel on the low pressure side is performed by the second solenoid-in valve 30FL, 30FR, and the pressure increase operation for the rear wheel on the high pressure side is performed with the number of rotations of the gate-in valve 25, the gate-out valve 13, and the motor M. To implement. The rotation speeds of the gate-in valve 25 and the motor M are controlled in accordance with the front wheel pressure increasing operation and the rear wheel pressure increasing operation.
In this case, the first brake fluid pressure P1 indicates the M / C pressure, and the second brake fluid pressure P2 indicates the high rear wheel pressure. Front wheel pressure cannot be detected.

Front wheel pressure increasing operation, rear wheel holding operation, front wheel pressure ≧ rear wheel pressure FIG. 37 is a hydraulic circuit showing the flow of brake fluid during pump control (front wheel pressure increasing operation, rear wheel holding operation, front wheel pressure ≧ rear wheel pressure). FIG. 38 and FIG. 38 are time charts.
The gate-in valve 25, the gate-out valve 13, the third solenoid-in valves 16RL and 16RR, and the pump P are PWM driven. That is, the pressure increase operation of the front wheel on the high pressure side is performed by the rotation speed of the gate-in valve 25, the gate-out valve 13, and the motor M. The rear wheel holding operation is performed by the third solenoid-in valves 16RL and 16RR.
In this case, the first brake fluid pressure P1 indicates the M / C pressure, and the second brake fluid pressure P2 indicates the front wheel pressure having a high pressure. The rear wheel pressure cannot be detected.
・ Front wheel pressure increasing operation, rear wheel holding operation, front wheel pressure <rear wheel pressure FIG. 39 is a hydraulic circuit showing the flow of brake fluid during pump control (front wheel pressure increasing operation, rear wheel holding operation, front wheel pressure <rear wheel pressure). 40 and 40 are time charts.
The gate-in valve 25, the gate-out valve 13 and the pump P are PWM-driven, and the second solenoid-in valves 30FL and 30FR are ON-driven. In other words, the pressure increase operation for the front wheel on the low pressure side is performed by the second solenoid-in valve 30FL, 30FR, and the operation for holding the rear wheel on the high pressure side is performed according to the rotation speed of the gate-in valve 25, the gate-out valve 13, and the motor M. carry out. Here, when the front wheel pressure increasing operation is performed, the rear wheel pressure is decreased, and therefore it is necessary to increase the pump pressure in accordance with the front wheel pressure increasing operation.
In this case, the first brake fluid pressure P1 indicates the M / C pressure, and the second brake fluid pressure P2 indicates the high rear wheel pressure. Front wheel pressure cannot be detected.
Front wheel pressure increasing operation, rear wheel pressure reducing operation, front wheel pressure ≧ rear wheel pressure FIG. 41 is a hydraulic circuit showing the flow of brake fluid during pump control (front wheel pressure increasing operation, rear wheel pressure reducing operation, front wheel pressure ≧ rear wheel pressure). 42 and 42 are time charts.
The gate-in valve 25, the gate-out valve 13, the third solenoid-in valves 16RL, 16RR and the pump P are PWM-driven, and the rear-wheel solenoid-out valves 29RL, 29RR are driven ON. That is, the pressure increase operation of the front wheel on the high pressure side is performed by the number of rotations of the gate-in valve 25, the gate-out valve 13, and the motor M, and the pressure reduction operation of the rear wheel is performed with the upstream pressure by the third solenoid in valves 16RL and 16RR. This is performed by shutting off and reducing pressure by solenoid out valves 29RL and 29RR. However, when the pressure reduction operation of the rear wheel is performed, the brake fluid that has flowed into the reservoir 34 is discharged by the pump P, and the front wheel pressure increases. In order to prevent this, the brake fluid is leaked from the gate-out valve 13 to the M / C line to prevent pressure increase.
In this case, the first brake fluid pressure P1 indicates the M / C pressure, and the second brake fluid pressure P2 indicates the front wheel pressure having a high pressure.

Front wheel pressure increasing operation, rear wheel pressure reducing operation, front wheel pressure <rear wheel pressure FIG. 43 is a hydraulic circuit showing the flow of brake fluid during pump control (front wheel pressure increasing operation, rear wheel pressure reducing operation, front wheel pressure <rear wheel pressure). 44 and 44 are time charts.
The gate-in valve 25, the gate-out valve 13 and the pump P are PWM-driven, and the second solenoid-in valves 30FL and 30FR are ON-driven. That is, the front wheel pressure increasing operation is performed by the second solenoid-in valves 30FL and 30FR, and the rear wheel pressure decreasing operation is performed by the gate-out valve 13. At this time, since the rear wheel pressure is reduced by performing the pressure increase operation on the front wheel, the pressure increase by the pump P is performed when the rear wheel pressure is reduced.
In this case, the first brake fluid pressure P1 indicates the M / C pressure, and the second brake fluid pressure indicates the rear wheel pressure.
Front wheel retention, rear wheel pressure increase, front wheel pressure ≧ rear wheel pressure FIG. 45 is a hydraulic circuit diagram showing the flow of brake fluid during pump control (front wheel retention, rear wheel pressure increase, front wheel pressure ≧ rear wheel pressure), FIG. Is a time chart.
The gate-in valve 25, the gate-out valve 13, the third solenoid-in valves 16RL and 16RR, and the pump P are PWM driven. That is, the holding operation of the front wheel on the high pressure side is performed by the number of rotations of the gate-in valve 25, the gate out valve 13, and the motor M, and the pressure increasing operation of the rear wheel on the low pressure side is performed by the third solenoid in valves 16RL and 16RR. carry out. Since the pressure of the front wheel is reduced by performing the pressure increase operation of the rear wheel, the pressure increase operation by the pump P is performed at the pressure increase operation timing of the rear wheel.
In this case, the first brake fluid pressure P1 indicates the M / C pressure, and the second brake fluid pressure indicates the front wheel pressure.
Front wheel retention, rear wheel pressure increase, front wheel pressure <rear wheel pressure FIG. 47 is a hydraulic circuit diagram showing the flow of brake fluid during pump control (front wheel retention, rear wheel pressure increase, front wheel pressure <rear wheel pressure), FIG. Is a time chart.
The gate-in valve 25, the gate-out valve 13, the third solenoid-in valves 16RL and 16RR and the pump P are driven by PWM, and the second solenoid-in valves 30FL and 30FR are driven ON. That is, the front wheel holding operation is performed by the second solenoid-in valves 30FL and 30FR, and the rear wheel pressure increasing operation is performed by the gate-in valve 25, the gate-out valve 13, and the motor M.
In this case, the first brake fluid pressure P1 indicates the M / C pressure, and the second brake fluid pressure indicates the rear wheel pressure.

・ Front wheel holding, rear wheel holding, front wheel pressure = rear wheel pressure FIG. 49 is a hydraulic circuit diagram showing the flow of brake fluid during pump control (front wheel holding, rear wheel holding, front wheel pressure = rear wheel pressure), and FIG. It is a chart.
The gate-out valve 13 and the pump P are driven by PWM. That is, the holding operation of the front and rear wheels is performed by turning off the gate-in valve 25 and decreasing the rotational speed of the motor M.
In this case, the first brake fluid pressure P1 represents the M / C pressure, and the second brake fluid pressure P2 represents the front and rear wheel pressure.
Front wheel holding, rear wheel holding, front wheel pressure> rear wheel pressure FIG. 51 is a hydraulic circuit diagram showing the flow of brake fluid during pump control (front wheel holding, rear wheel holding, front wheel pressure> rear wheel pressure), FIG. It is a time chart.
The gate-out valve 13, the third solenoid-in valves 16RL and 16RR and the pump P are PWM driven. That is, the holding operation of the front wheel on the high pressure side is performed by turning off the gate-in valve 25 and the rotational speed of the motor M, and the holding operation of the rear wheel on the low pressure side is performed by the third solenoid-in valves 16RL and 16RR.
In this case, the first brake fluid pressure P1 indicates the M / C pressure, and the second brake fluid pressure P2 indicates the front wheel pressure. The rear wheel pressure cannot be detected.
Front wheel holding, rear wheel holding, front wheel pressure <rear wheel pressure FIG. 53 is a hydraulic circuit diagram showing the flow of brake fluid during pump control (front wheel holding, rear wheel holding, front wheel pressure <rear wheel pressure), and FIG. It is a chart.
The gate-out valve 13 and the pump P are PWM-driven, and the second solenoid-in valves 30FL and 30FR are ON-driven. That is, the holding operation of the front wheel is performed by the second solenoid-in valves 30FL and 30FR, and the holding operation of the rear wheel is performed by turning off the gate-in valve 25 and decreasing the rotational speed of the motor M.
In this case, the first brake fluid pressure P1 indicates the M / C pressure, and the second brake fluid pressure P2 indicates the rear wheel pressure. Front wheel pressure cannot be detected.

Front wheel holding, rear wheel pressure reduction, front wheel pressure ≧ rear wheel pressure FIG. 55 is a hydraulic circuit diagram showing the flow of brake fluid during pump control (front wheel holding, rear wheel pressure reduction, front wheel pressure ≧ rear wheel pressure), and FIG. It is a chart.
The gate-out valve 13, the third solenoid-in valves 16RL and 16RR, and the pump P are driven by PWM, and the rear-wheel solenoid out valves 29RL and 29RR are driven ON. That is, the holding operation of the front wheel is performed by turning off the gate-in valve 25 and the rotation speed of the motor M, and the pressure reduction operation of the rear wheel is performed by shutting off the upstream pressure by the third solenoid-in valve 16RL, 16RR and the solenoid-out valve 29RL, Performed by reducing pressure with 29RR. However, if the rear wheel pressure reduction operation is performed, the brake fluid that has flowed into the reservoir 34 is discharged by the pump P and the front wheel pressure rises. To prevent this, brake fluid is supplied from the gate-out valve 13 to the M / C line. Prevent leakage pressure rise.
In this case, the first brake fluid pressure P1 indicates the M / C pressure, and the second brake fluid pressure P2 indicates the front wheel pressure.
Front wheel holding, rear wheel pressure reduction, front wheel pressure <rear wheel pressure FIG. 57 is a hydraulic circuit diagram showing the flow of brake fluid during pump control (front wheel holding, rear wheel pressure reduction, front wheel pressure <rear wheel pressure), and FIG. It is a chart.
The gate-out valve 13 and the pump P are PWM-driven, and the second solenoid-in valves 30FL and 30FR are ON-driven. That is, the front wheel holding operation is performed by the second solenoid-in valves 30FL and 30FR, and the rear wheel pressure-reducing operation is performed by releasing the brake fluid from the gate-out valve 13 to the M / C line with the motor M rotating at a low speed. .
In this case, the first brake fluid pressure P1 indicates the M / C pressure, and the second brake fluid pressure P2 indicates the rear wheel pressure. Front wheel pressure cannot be detected.
Front wheel pressure reduction, rear wheel pressure increase, front wheel pressure ≧ rear wheel pressure FIG. 59 is a hydraulic circuit diagram showing the flow of brake fluid during pump control (front wheel pressure reduction, rear wheel pressure increase, front wheel pressure ≧ rear wheel pressure), FIG. Is a time chart.
The gate-in valve 25 is turned off or PWM-driven, and the gate-out valve 13, the third solenoid-in valves 16RL and 16RR, and the pump P are PWM-driven. That is, the pressure reduction operation of the front wheels is performed by letting the motor M run at a low speed and letting the brake fluid escape from the gate-out valve 13 to the M / C line. The rear wheel pressure increasing operation is performed by the third solenoid-in valves 16RL and 16RR. If the front wheel pressure has decreased due to the pressure increase operation on the rear wheel, the front wheel pressure is maintained by increasing the pressure with the pump P.
In this case, the first brake fluid pressure P1 indicates the M / C pressure, and the second brake fluid pressure P2 indicates the front wheel pressure. The rear wheel pressure cannot be detected.

Front wheel pressure reduction, rear wheel pressure increase, front wheel pressure <rear wheel pressure FIG. 61 is a hydraulic circuit diagram showing the flow of brake fluid during pump control (front wheel pressure reduction, rear wheel pressure increase, front wheel pressure <rear wheel pressure), FIG. Is a time chart.
The gate-in valve 25, the gate-out valve 13 and the pump P are PWM-driven, and the second solenoid-in valves 30FL, 30FR and the front-wheel solenoid out valves 29FL, 29FR are driven ON. In other words, the pressure reduction operation for the front wheel is performed by shutting off the upstream pressure by the second solenoid-in valve 30FL, 30FR and the pressure reduction by the solenoid-out valve 29RL, 29RR, and the pressure increase operation for the rear wheel is performed by the gate-in valve 25 and the motor M. Carry out by the number of rotations. However, the brake fluid that has flowed into the reservoir 34 due to the decompression operation of the front wheels is discharged by the pump P, and the rear wheel pressure increases too much, so the pressure increases by letting the brake fluid escape to the M / C line by the gate-out valve 13 prevent.
In this case, the first brake fluid pressure P1 indicates the M / C pressure, and the second brake fluid pressure P2 indicates the rear wheel pressure. Front wheel pressure cannot be detected.
Front wheel pressure reduction, rear wheel holding, front wheel pressure ≧ rear wheel pressure FIG. 63 is a hydraulic circuit diagram showing the flow of brake fluid during pump control (front wheel pressure reduction, rear wheel holding, front wheel pressure ≧ rear wheel pressure), and FIG. It is a chart.
-The gate-in valve 25, the gate-out valve 13, the third solenoid-in valves 16RL and 16RR and the pump P are PWM-driven. That is, the front wheel pressure reduction operation is performed by turning off the gate-in valve 25 and the rotational speed of the motor M, and the rear wheel holding operation is performed by blocking the upstream pressure from the third solenoid in valves 16RL and 16RR.
In this case, the first brake fluid pressure P1 indicates the M / C pressure, and the second brake fluid pressure P2 indicates the front wheel pressure. The rear wheel pressure cannot be detected.

Front wheel pressure reduction, rear wheel holding, front wheel pressure <rear wheel pressure FIG. 65 is a hydraulic circuit diagram showing the flow of brake fluid during pump control (front wheel pressure reduction, rear wheel holding, front wheel pressure <rear wheel pressure), and FIG. It is a chart.
The gate-out valve 13 and the pump P are PWM-driven, and the second solenoid-in valves 30FL and 30FR and the front-wheel solenoid out valves 29FL and 29FR are driven ON. That is, the pressure reduction operation of the front wheels is performed by blocking the upstream pressure with the second solenoid-in valves 30FL and 30FR and reducing the pressure with the solenoid-out valves 29FL and 29FR. The rear wheel holding operation is performed by turning off the gate-in valve 25 and decreasing the rotational speed of the motor M. Since the brake fluid flows into the reservoir 34 by the pressure reduction operation of the front wheel and is discharged by the pump P, the rear wheel pressure increases too much. Therefore, the brake fluid is released to the M / C line by the gate-out valve 13 to prevent the pressure increase.
In this case, the first brake fluid pressure P1 indicates the M / C pressure, and the second brake fluid pressure P2 indicates the rear wheel pressure.
Front wheel pressure reduction, rear wheel pressure reduction, front wheel pressure ≧ rear wheel pressure FIG. 67 is a hydraulic circuit diagram showing the flow of brake fluid during pump control (front wheel pressure reduction, rear wheel pressure reduction, front wheel pressure ≧ rear wheel pressure), and FIG. It is a chart.
The gate-out valve 13, the third solenoid-in valves 16RL and 16RR, and the pump P are driven by PWM, and the rear-wheel solenoid out valves 29RL and 29RR are driven ON. That is, the decompression operation of the front wheels is performed by turning off the gate-in valve 25 and decreasing the rotational speed of the motor M. The rear wheel pressure reduction operation is performed by shutting off the upstream pressure by the third solenoid-in valves 16RL and 16RR and pressure reduction by the solenoid-out valves 29RL and 29RR. Since the brake fluid flows into the reservoir 34 due to the pressure reduction operation of the rear wheel and is discharged by the pump P, the front wheel pressure increases excessively. Therefore, the brake fluid is released to the M / C line by the gate-out valve 13 to prevent the pressure increase.
In this case, the first brake fluid pressure P1 indicates the M / C pressure, and the second brake fluid pressure P2 indicates the front wheel pressure. The rear wheel pressure cannot be detected.
Front wheel pressure reduction, rear wheel pressure reduction, front wheel pressure <rear wheel pressure FIG. 69 is a hydraulic circuit diagram showing the flow of brake fluid during pump control (front wheel pressure reduction, rear wheel pressure reduction, front wheel pressure <rear wheel pressure), and FIG. It is a chart.
The gate-out valve 13, the second solenoid-in valves 30FL and 30FR, and the pump P are driven by PWM, and the solenoid-out valves 29FL and 20FR on the front wheels are driven ON. That is, the front wheel pressure reduction operation is performed by shutting off the upstream pressure by the second solenoid-in valves 30FL and 30FR and the pressure reduction by the solenoid-out valves 29RL and 29RR, and the rear wheel pressure reduction operation is performed by turning off the gate-in valve 25 and the motor M. This is performed by lowering the rotational speed. Since the brake fluid flows into the reservoir 34 by the pressure reduction operation of the front wheel and is discharged by the pump P, the rear wheel pressure increases too much. Therefore, the brake fluid is released to the M / C line by the gate-out valve 13 to prevent the pressure increase.
In this case, the first brake fluid pressure indicates the M / C pressure, and the second brake fluid pressure indicates the rear wheel pressure. Front wheel pressure cannot be detected.

[Detection of high-pressure wheel cylinder pressure]
In recent years, brake control tends to be complicated from the viewpoint of safety and convenience, and in order to improve controllability, it is more necessary than ever to sense the pressure of the wheel cylinder. Here, since attaching an expensive pressure sensor to each wheel cylinder causes a cost increase, it is desired to realize a brake control device capable of sensing the wheel cylinder pressure in more scenes with fewer pressure sensors. .
In the conventional brake control device, in the hydraulic control device having an X-pipe type brake piping system, a circuit for connecting the wheel cylinder for the left rear wheel and the wheel cylinder for the right rear wheel is provided, and a pressure sensor is provided on this circuit. The detection target of the pressure sensor can be switched between the two brake piping systems by switching the open / close state of the electromagnetic valves provided on the left and right sides of the pressure sensor.
However, the conventional device cannot detect the front wheel pressure when performing control for differentiating the front and rear wheel pressures such as ABS control and pump pressure increase control. For this reason, for example, in a scene where only the front wheel pressure is controlled to be pump-intensified, there is a problem that the front wheel pressure, which is important for controllability, cannot be detected. In addition, when pressure fluctuations occur when switching the open / close state of the electromagnetic valves provided on the left and right sides of the pressure sensor, it is difficult to determine whether or not the same pressure is detected. Furthermore, when the open / close state of the solenoid valve is switched while there is a pressure difference between the left and right piping systems, the brake fluid may move from the high pressure side system to the low pressure side system, leading to a decrease in the fluid volume on the high pressure side. There is concern about the deterioration of controllability.

On the other hand, in the brake control device of the first embodiment, the second solenoid in valve 30FL, 30FR is added to the downstream side (wheel cylinder side) of the first solenoid in valve 16FL, 16FR, and the added second solenoid in valve 30FL is added. The second pressure sensors 33FL and 33FR are installed between the 30FR and the first solenoid-in valve 16FL and 16FR.
For this reason, in a scene where front wheel pressure> rear wheel pressure, the second solenoid-in valves 30FL, 30FR are opened (OFF), whereby the front wheel pressure on the high pressure side can be detected by the second pressure sensors 33FL, 33FR.
On the other hand, in a scene where the front wheel pressure is smaller than the rear wheel pressure, the second solenoid-in valves 30FL and 30FR are closed (ON), whereby the rear wheel pressure on the high pressure side can be detected by the second pressure sensors 33FL and 33FR.
In other words, the wheel cylinder pressure on the high-pressure side required to ensure controllability is ensured during pressure increase / decrease by the pump P (simultaneous front and rear wheels, one front wheel, one rear wheel) and pressure increase / decrease by the brake pedal BP. Can be detected. In addition, since the configuration of the few pressure sensors (second pressure sensors 33FL and 33FR), an increase in cost can be suppressed.

Next, the effect will be described.
The brake control device according to the first embodiment has the following effects.
Between the first brake circuit (pipe 11, pipe 12P, 12S) with one end connected to the master cylinder M / C, and the other end of the first brake circuit and the front wheel wheel cylinder W / C (FL, FR) First wheel cylinder circuits 12FL, 12FR for connecting the second wheel cylinder circuits 12RL, 12RR for connecting the other end of the first brake circuit and the wheel cylinder W / C (RL, RR) for the rear wheels, A pump P capable of flowing the brake fluid in the circuit, and a first solenoid-in valve 16FL, 16FR and a first solenoid-in valve 16FL, 16FR provided in the first wheel cylinder circuit 12FL, 12FR are connected in series. Between the solenoid-in valve 30FL, 30FR, the third solenoid-in valve 16RL, 16RR provided in the second wheel cylinder circuit 12RL, 12RR, and between the first solenoid-in valve 16FL, 16FR and the second solenoid-in valve 30FL, 30FR The second pressure sensors 33FL and 33FR provided in the pump, the pump P and each solenoid It drives the Idoinbarubu with controlling the hydraulic pressure in each wheel cylinder, with the second pressure sensor 33FL, and the brake control unit BCU which hydraulic pressure within the detecting circuit is input by 33FR, a.
Therefore, it is possible to detect the wheel cylinder pressure on the high pressure side while reducing the pressure by the pump P and at the time of increasing / decreasing the pressure by the brake pedal BP. And controllability can be improved together.

[Other Examples]
As mentioned above, although the form for implementing this invention was demonstrated based on the Example, the concrete structure of this invention is not limited to the structure shown in the Example, and is the range which does not deviate from the summary of invention. Any design changes are included in the present invention.
For example, in the embodiment, the second solenoid-in valve and the pressure sensor are provided on the front wheel side, but may be provided on the rear wheel side.
Moreover, although the example applied to the hydraulic pressure control device having the brake piping system of the X piping type in the embodiment, it may be applied to the hydraulic pressure control device having the brake piping system of the H piping type.

11 Pipe line (1st brake circuit)
12FL, 12FR pipeline (first wheel cylinder circuit)
12RL, 12RR pipeline (second wheel cylinder circuit)
12P, 12S pipeline (first brake circuit)
16FL, 16FR Solenoid In Valve (First Solenoid In Valve)
16RL, 16RR Solenoid In Valve (3rd Solenoid In Valve)
30FL, 30FR Solenoid In Valve (Second Solenoid In Valve)
33FL, 33FR Second pressure sensor (pressure sensor)
BCU Brake control unit (controller)
M / C master cylinder
P pump
W / C (FL, FR) wheel cylinder (first wheel cylinder)
W / C (RL, RR) wheel cylinder (second wheel cylinder)

Claims (1)

A first brake circuit having one end connected to the master cylinder;
A first wheel cylinder circuit connecting the other end of the first brake circuit and the first wheel cylinder;
A second wheel cylinder circuit connecting the other end of the first brake circuit and a second wheel cylinder;
A pump capable of flowing the brake fluid in the circuit;
A first solenoid-in valve provided in the first wheel cylinder circuit and a second solenoid-in valve provided in series with the first solenoid-in valve;
A third solenoid-in valve provided in the second wheel cylinder circuit;
A pressure sensor provided between the first solenoid-in valve and the second solenoid-in valve;
A controller for controlling the hydraulic pressure in each wheel cylinder by driving the pump and each solenoid-in valve, and for inputting the hydraulic pressure in the circuit detected by the pressure sensor;
A brake control device comprising:

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