JP4806228B2 - Brake hydraulic pressure control device for vehicles - Google Patents

Description

  The present invention relates to a vehicle brake fluid pressure control device, and more particularly to a vehicle brake fluid pressure control device that pressurizes brake fluid pressure from a master cylinder with a pump.

  In a conventional vehicle brake device, the pump is driven by a motor and the brake fluid pressure is increased regardless of the operation of the brake pedal (see, for example, Patent Document 1). In Patent Document 1, the motor is driven at a high rotation (duty ratio 100%) for a predetermined time, and the motor is driven at a low rotation (low duty ratio) after a predetermined time has elapsed, thereby suppressing the operating noise of the motor. An apparatus capable of performing is disclosed.

Japanese Unexamined Patent Publication No. 2000-203401 (paragraph 0038)

However, in the apparatus described in Patent Document 1, the suppression of the operation noise of the motor is not sufficient, and further suppression of the operation noise is required.
Further, when a part of the brake fluid pressurized by the pump is returned to the master cylinder, the operation sound of the cut valve is likely to be frequently generated due to the pulsation returning to the cut valve.

  The present invention was devised to solve the above-described problems, and provides a vehicle brake hydraulic pressure control device capable of suppressing operating noise and pulsation while maintaining boosting performance by a motor. Let it be an issue.

In order to solve the above-mentioned problem, the invention according to claim 1 of the present invention is characterized in that one hydraulic path connected to the hydraulic pressure supply means is connected to a plurality of wheel brakes, and the brake hydraulic pressures of the plurality of wheel brakes. The brake hydraulic pressure control device for a vehicle controls the hydraulic pressure to the respective target hydraulic pressures, and includes a linear solenoid valve provided in the one hydraulic pressure path, and the wheel more than the linear solenoid valve in the one hydraulic pressure path. A pump capable of pressurizing the brake hydraulic pressure on the brake side, a motor capable of controlling the rotational speed for driving the pump, a motor drive unit for controlling the motor by rotational speed control, and a target hydraulic pressure for each of the wheel brakes A target hydraulic pressure setting unit for setting the brake fluid pressure and a brake hydraulic pressure acquisition means for acquiring the brake hydraulic pressure of each of the wheel brakes, and the motor driving unit performs duty control on the rotational speed control of the motor When the behavior stabilization control of the vehicle is started, the motor is driven at a rotational speed smaller than the maximum rotational speed, and then, during the execution of the behavior stabilization control, When the wheel brake having the maximum target hydraulic pressure is selected and the target hydraulic pressure is larger than the brake hydraulic pressure in the selected wheel brake and the difference becomes a predetermined value or more, the motor is always used. Is driven at a duty ratio of 100% so as to be the maximum rotational speed, and subsequently, during execution of the behavior stabilization control, the target hydraulic pressure is greater than the brake hydraulic pressure in the selected wheel brake, When the difference becomes less than a predetermined value, the motor is driven at a rotational speed smaller than the maximum rotational speed.

According to a second aspect of the present invention, the one hydraulic path connected to the hydraulic pressure supply means is connected to the plurality of wheel brakes, and the brake hydraulic pressures of the plurality of wheel brakes are set to the respective target hydraulic pressures. A brake hydraulic pressure control device for a vehicle that controls, a linear solenoid valve provided in the one hydraulic pressure path, and a brake hydraulic pressure in a hydraulic pressure path on a wheel brake side from the linear solenoid valve A pump, a motor capable of controlling the rotational speed for driving the pump, a motor driving unit for driving and controlling the motor by rotational speed control, a target hydraulic pressure setting unit for setting a target hydraulic pressure of each wheel brake, Brake fluid pressure acquisition means for acquiring the brake fluid pressure of each of the wheel brakes, and the motor drive unit performs duty control to control the number of rotations of the motor, thereby opening vehicle behavior stabilization control. When it is, the motor is driven at low rotational speed than the maximum rotational speed, followed by the, during the execution of the behavior stabilization control, the target fluid pressure of at least one of the wheel brakes is a maximum When a wheel brake is selected and the target hydraulic pressure is larger than the brake hydraulic pressure in the selected wheel brake and the difference becomes a predetermined value or more, the motor is always set to the maximum rotational speed. driven at a duty ratio of 100%, followed by, in the behavior stabilizing control during running, greater than the target hydraulic pressure is the brake fluid pressure at the selected wheel brake, and the difference in all of the wheel brake When the motor becomes less than a predetermined value, the motor is driven at a rotational speed smaller than the maximum rotational speed.

The “maximum rotational speed” here refers to the maximum value of the rotational speed when the motor is subjected to the control of the present invention.
The “difference” is a value obtained by subtracting the brake hydraulic pressure from the target hydraulic pressure in one wheel brake, and the “predetermined value” is a positive value.
According to the vehicle brake hydraulic pressure control device of the first or second aspect, the time for driving the motor with the maximum duty ratio can be adjusted according to the necessity of control. The operation noise and pulsation can be suppressed while maintaining.
Further, according to such a vehicle brake hydraulic pressure control device, since the rotational speed is controlled by controlling the duty ratio of the motor, the driving of the motor can be controlled easily and accurately.

The invention according to claim 3 is the brake fluid pressure control device for a vehicle according to claim 1 or 2, wherein the motor driving unit drives the motor at the small rotational speed. In the selected wheel brake, the brake fluid pressure is driven to follow the target fluid pressure.

According to such a vehicle brake fluid pressure control device, the brake fluid pressure of the selected wheel brake can be controlled by driving the motor. Further, the driving amount of the motor can be suppressed to the minimum necessary, and the operation noise and pulsation can be further suppressed.

  Further, the invention according to claim 4 is the vehicle brake hydraulic pressure control device according to any one of claims 1 to 3, wherein the brake hydraulic pressure acquisition means is provided for each wheel brake. An estimated brake fluid pressure is acquired.

The brake fluid pressure detected by the brake fluid pressure detecting means includes an actual measurement value (actual brake fluid pressure) and an estimated value (estimated brake fluid pressure).
The actually measured brake fluid pressure can be acquired by a pressure sensor provided for each wheel brake.
The estimated brake fluid pressure is obtained, for example, by calculation based on the brake fluid pressure in one fluid pressure path detected by a pressure sensor provided in one fluid pressure passage and the driving of the vehicle brake fluid pressure control device. can do.
According to such a vehicle brake fluid pressure control device, the estimated value is acquired as the brake fluid pressure, so that the number of pressure sensors can be reduced as compared with the case of acquiring the actual measurement value.

  ADVANTAGE OF THE INVENTION According to this invention, the brake fluid pressure control apparatus for vehicles which can suppress an operation sound and a pulsation can be provided, maintaining pressure | voltage rise performance.

Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
FIG. 1 is a configuration diagram of a vehicle including a vehicle brake hydraulic pressure control device according to an embodiment of the present invention. FIG. 2 is a brake hydraulic circuit diagram of the vehicle brake hydraulic pressure control device. It is.
As shown in FIG. 1, the vehicle brake fluid pressure control device 100 is for appropriately controlling the braking force (brake fluid pressure) applied to each wheel T of the vehicle CR, and is provided with an oil passage and various parts. The hydraulic unit 10 and the control device 20 for appropriately controlling various components in the hydraulic unit 10 are mainly provided. Further, the control device 20 of the vehicle brake hydraulic pressure control device 100 includes a wheel speed sensor 91 that detects the wheel speed of the wheel T, a steering angle sensor 92 that detects the steering angle of the steering ST, and a lateral direction of the vehicle CR. A lateral acceleration sensor 93 that detects the working acceleration, a yaw rate sensor 94 that detects the turning angular velocity of the vehicle CR, and an acceleration sensor 95 that detects the longitudinal acceleration of the vehicle CR are connected. The detection results of the sensors 91 to 95 are output to the control device 20.
The control device 20 includes, for example, a CPU, a RAM, a ROM, and an input / output circuit, and inputs from the wheel speed sensor 91, the steering angle sensor 92, the lateral acceleration sensor 93, the yaw rate sensor 94, and the acceleration sensor 95, and the ROM. Control is performed by performing each arithmetic processing based on the stored program and data. The wheel cylinder H is a fluid that converts the brake fluid pressure generated by the master cylinder M and the vehicle brake fluid pressure control device 100 into the operating force of the wheel brakes FR, FL, RR, RL provided on each wheel T. Each of which is connected to the hydraulic unit 10 of the vehicle brake hydraulic pressure control device 100 via a pipe.

  As shown in FIG. 2, the hydraulic unit 10 of the vehicle brake hydraulic pressure control device 100 includes a master cylinder M that is a hydraulic pressure supply unit that generates a brake hydraulic pressure in accordance with a pedaling force applied to the brake pedal BP by the driver. The pump body 10a, which is a base body having an oil passage through which brake fluid flows, is disposed between the wheel brakes FR, FL, RR, RL, a plurality of inlet valves 1, outlet valves 2, etc. arranged on the oil passage It is composed of The two output ports M1, M2 of the master cylinder M are connected to the inlet port 121 of the pump body 10a, and the outlet port 122 of the pump body 10a is connected to each brake FR, FL, RR, RL. In normal times, the oil passage is communicated from the inlet port 121 to the outlet port 122 in the pump body 10a, so that the depression force of the brake pedal BP is transmitted to the wheel brakes FL, RR, RL, FR. It is like that.

  As shown in FIG. 2, the hydraulic unit 10 of the vehicle hydraulic pressure control device 100 includes a master cylinder M that generates brake hydraulic pressure corresponding to the pedaling force applied by the driver to the brake pedal BP, and wheel brakes FL, FR, It arrange | positions between RL and RR. The two output ports M1, M2 of the master cylinder M are connected to the inlet port 121 of the hydraulic unit 10, and the outlet port 122 of the hydraulic unit 10 is connected to each wheel brake FL, FR, RL, RR. . In normal times, the oil pressure path of the brake pedal BP is transmitted to each of the wheel brakes FL, FR, RL, and RR because the oil passage communicates from the inlet port 121 to the outlet port 122 in the hydraulic unit 10. It has become so.

  Here, the oil path starting from the output port M1 leads to the wheel brake FL on the left side of the front wheel and the wheel brake RR on the right side of the rear wheel, and the oil path starting from the output port M2 is set to the wheel brake FR on the right side of the front wheel and the left side of the rear wheel. To the wheel brake RL. Hereinafter, the oil passage starting from the output port M1 is referred to as “first system”, and the oil passage starting from the output port M2 is referred to as “second system”.

  The hydraulic unit 10 is provided with two control valve means V corresponding to each wheel brake FL, RR in the first system, and similarly corresponding to each wheel brake RL, FR in the second system. Two control valve means V are provided. The hydraulic unit 10 is provided with a reservoir 3, a pump 4, a damper 5, an orifice 5a, a regulator R, a suction valve 7, and a storage chamber 7a in each of the first system and the second system. A common motor (DC motor) 9 for driving the first system pump 4 and the second system pump 4 is provided. The motor 9 is a motor capable of controlling the rotational speed. In this embodiment, the rotational speed is controlled by duty control. In the present embodiment, the pressure sensor 8 is provided only in the second system.

In the following, the oil passage from the output ports M1, M2 of the master cylinder M to each regulator R is referred to as “output hydraulic pressure passage A1,” and the oil passage from the first system regulator R to the wheel brakes FL, RR and The oil passages from the second system regulator R to the wheel brakes RL and FR are respectively referred to as “wheel hydraulic pressure passage B”. In addition, an oil path from the output hydraulic pressure path A1 to the pump 4 is referred to as “suction hydraulic pressure path C”, an oil path from the pump 4 to the wheel hydraulic pressure path B is referred to as “discharge hydraulic pressure path D”, and The oil passage from the wheel fluid pressure passage B to the suction fluid pressure passage C is referred to as “open passage E”.
Here, “output hydraulic pressure path A1” corresponds to “first hydraulic pressure path” in claims, and “wheel hydraulic pressure path B” corresponds to “second hydraulic pressure path” in claims. Equivalent to.

  The control valve means V opens the wheel hydraulic pressure path B while blocking the open path E, and the pressure reducing condition that blocks the wheel hydraulic pressure path B and opens the open path E, and blocks the wheel hydraulic pressure path B. However, it has a function of switching the holding state that shuts off the open path E, and includes an inlet valve 1, an outlet valve 2, and a check valve 1a.

  The inlet valve 1 is a normally open electromagnetic valve provided between each wheel brake FL, RR, RL, FR and the master cylinder M, that is, in the wheel hydraulic pressure path B. The inlet valve 1 is normally open, thereby allowing brake fluid pressure to be transmitted from the master cylinder M to the wheel brakes FL, FR, RL, RR. Further, the inlet valve 1 is blocked by the control device 20 when the wheel T is about to be locked, thereby blocking the brake hydraulic pressure transmitted from the brake pedal BP to each wheel brake FL, FR, RL, RR. .

  The outlet valve 2 is a normally closed electromagnetic valve interposed between each wheel brake FL, RR, RL, FR and each reservoir 3, that is, between the wheel hydraulic pressure path B and the release path E. The outlet valve 2 is normally closed, but is released by the control device 20 when the wheel T is about to be locked, so that the brake fluid pressure acting on each wheel brake FL, FR, RL, RR is reduced. Relief to each reservoir 3

  The check valve 1a is connected to each inlet valve 1 in parallel. This check valve 1a is a valve that only allows the brake fluid to flow from each wheel brake FL, FR, RL, RR side to the master cylinder M side, and when the input from the brake pedal BP is released, Even when the valve 1 is closed, the brake fluid is allowed to flow from each wheel brake FL, FR, RL, RR side to the master cylinder M side.

  The reservoir 3 is provided in the release path E and has a function of absorbing brake fluid pressure that is released when each outlet valve 2 is opened. Further, between the reservoir 3 and the pump 4, a check valve 3a that allows only the inflow of brake fluid from the reservoir 3 side to the pump 4 side is interposed.

  The pump 4 is interposed between the suction hydraulic pressure path C leading to the output hydraulic pressure path A1 and the discharge hydraulic pressure path D leading to the wheel hydraulic pressure path B, and sucks the brake fluid stored in the reservoir 3 And has a function of discharging to the discharge hydraulic pressure path D. As a result, the pressure states of the output hydraulic pressure passage A1 and the wheel hydraulic pressure passage B that have been reduced by absorbing the brake hydraulic pressure by the reservoir 3 are recovered. Further, in this pump 4, a cut valve 6 to be described later blocks the inflow of brake fluid from the output hydraulic pressure path A 1 to the wheel hydraulic pressure path B, and a suction valve 7 to be described later opens the suction hydraulic pressure path C. The brake fluid stored in the master cylinder M, the output hydraulic pressure path A1, the suction hydraulic pressure path C, and the storage chamber 7a is sucked and discharged to the discharge hydraulic pressure path D. This makes it possible to apply brake fluid pressure to each wheel brake FL, FR, RL, RR during non-pedal operation. That is, the pump 4 can pressurize the brake fluid pressure on the wheel brakes FL, RR (RL, FR) side with respect to the cut valve 6 in the output fluid pressure path A1. The amount of brake fluid discharged by the pump 4 depends on the rotation speed (duty ratio) of the motor 9. That is, as the rotation speed (duty ratio) of the motor 9 increases, the amount of brake fluid discharged by the pump 4 also increases.

  The damper 5 and the orifice 5a attenuate the pulsation of the pressure of the brake fluid discharged from the pump 4 and the pulsation generated by the operation of the regulator R described later by the cooperative action.

  The regulator R has a function of switching between a state where the brake fluid is allowed to flow into the wheel fluid pressure passage B from the output fluid pressure passage A1 and a state where the brake fluid is blocked, and a brake fluid flow from the output fluid pressure passage A1 to the wheel fluid pressure passage B. It has a function of adjusting the brake fluid pressure in the wheel fluid pressure passage B and the discharge fluid pressure passage D to a set value or less when the inflow is blocked, and is configured to include a cut valve 6 and a check valve 6a. ing.

  The cut valve 6 is a normally open linear solenoid valve interposed between the output hydraulic pressure path A1 leading to the master cylinder M and the wheel hydraulic pressure path B leading to each wheel brake FL, FR, RL, RR. The state where the inflow of the brake fluid from the output hydraulic pressure path A1 to the wheel hydraulic pressure path B is allowed and the state where the brake fluid is blocked are switched. That is, the cut valve 6 is a linear solenoid valve capable of adjusting the valve opening pressure by controlling energization to the solenoid. The cut valve 6 is normally open, thereby allowing the brake fluid pressure to be transmitted from the master cylinder M to the wheel brakes FL, FR, RL, RR. Further, the cut valve 6 is a control device when the pump 4 is operated when the pedal is not operated, in other words, when the brake fluid pressure is applied to the wheel brakes FL, FR, RL, and RR when the pedal is not operated. The hydraulic pressure in the wheel hydraulic pressure path B is controlled by the balance between the hydraulic pressure applied from the wheel hydraulic pressure path B to the regulator R and the force to close the valve controlled by energizing the solenoid. It can be adjusted by opening to the output hydraulic pressure path A1 as appropriate.

  The check valve 6a is connected to each cut valve 6 in parallel. The check valve 6a is a one-way valve that allows the flow of brake fluid from the output hydraulic pressure path A1 to the wheel hydraulic pressure path B.

  The suction valve 7 is a normally closed electromagnetic valve provided in the suction fluid pressure passage C, and switches between a state in which the suction fluid pressure passage C is opened and a state in which the suction fluid pressure passage C is shut off. The suction valve 7 is in a non-pedal operation, and when the cut valve 6 is in a state of blocking the inflow of brake fluid from the output hydraulic pressure path A1 to the wheel hydraulic pressure path B, in other words, in the non-pedal operation. When the brake fluid pressure is applied to the wheel brakes FL, FR, RL, RR, it is opened (opened) by the control of the control device 20.

  The storage chamber 7 a is the suction fluid pressure path C and is provided between the pump 4 and the suction valve 7. The storage chamber 7a stores brake fluid, and the capacity of the brake fluid stored in the suction fluid pressure path C is thereby substantially increased.

  The pressure sensor 8 detects the brake hydraulic pressure in the output hydraulic pressure path A1, and the detection result is taken into the control device 20 as needed. Then, it is determined whether or not the brake fluid pressure is output from the master cylinder M by the control device 20, that is, whether or not the brake pedal BP is stepped on, and further, the brake fluid pressure detected by the pressure sensor 8 is determined. Based on the size, the vehicle CR is controlled.

FIG. 3 is a block diagram of the control device.
As shown in FIG. 3, the control device 20 opens and closes the control valve means V, the cut valve 6 and the suction valve 7 in the hydraulic unit 10 and the motor 9 based on the signals input from the sensors 91 to 95. The operation is controlled to control the operation of each wheel brake FL, RR, RL, FR. The control device 20 includes a target hydraulic pressure setting unit 21, a brake hydraulic pressure calculation unit 22, a valve driving unit 23, and a motor driving unit 24 as functional units.

The target hydraulic pressure setting unit 21 selects a control logic based on signals input from the sensors 91 to 95, and the target hydraulic pressures PP _FL , FR of each wheel brake FL, RR, RL, FR according to the control logic. Set PP _RR , PP _RL , PP _FR . This setting method may be performed by a conventionally known method and is not particularly limited. For example, the vehicle body speed is calculated from the wheel speeds of the four wheels T. Then, the slip ratio is calculated from the wheel speed and the vehicle body speed. Further, based on the lateral acceleration and the longitudinal acceleration of the vehicle body CR, a combined acceleration is calculated, and a road friction coefficient is estimated from the combined acceleration. Based on the friction coefficient, the slip ratio, and the current brake hydraulic pressures P _FL , P _RR , P _RL , P _FR of the wheel cylinder H, the target hydraulic pressures PP _FL , PP _{RR of the} wheel brakes FL, RR, RL, FR , PP _RL , PP _FR can be set.

Further, the target hydraulic pressure setting unit 21 compares the same system among the target hydraulic pressures PP _FL , PP _RR , PP _RL , PP _FR and cuts the highest target hydraulic pressure among them in the system. The target hydraulic pressure PP _REG of the valve 6 is set. The target hydraulic pressure PP _REG is a target hydraulic pressure of the output hydraulic pressure path A1 that is regulated by the cut valve 6 and that is closer to the wheel brake than the cut valve 6.
The set target hydraulic pressures PP _FL , PP _RR , PP _RL , PP _FR , PP _REG are appropriately output to the valve drive unit 23 and the motor drive unit 24.

The brake fluid pressure calculation unit 22 uses the brake fluid pressure detected by the pressure sensor 8 and the drive amount of each solenoid valve 1, 2, 6 by the valve drive unit 23 to brake the wheel brakes FL, RR, RL, FR. Fluid pressures (estimated brake fluid pressures) P _FL , P _RR , P _RL , P _FR are calculated.
That is, the combination of the pressure sensor 8 and the brake fluid pressure calculation unit 22 is an example of “brake fluid pressure acquisition means” in the claims.
The calculated brake fluid pressure is output to the valve drive unit 23 and the motor drive unit 24.

The valve drive unit 23 uses a conventionally known method so that the brake hydraulic pressure of the wheel cylinder H of each wheel brake FL, RR, RL, FR matches the target hydraulic pressure set by the target hydraulic pressure setting unit 22. A pulse signal for operating each inlet valve 1, outlet valve 2, cut valve 6 and suction valve 7 in the unit 10 is output to the hydraulic unit 10. For example, the larger the difference between the brake hydraulic pressures P _FL , P _RR , P _RL , P _FR and the target hydraulic pressures PP _FL , PP _RR , PP _RL , PP _{FR of} this pulse signal, the greater the pulse signal. Output a pulse.
The valve driver 23, each based on the target fluid pressure _{PP FL, PP RR, PP RL} , PP FR, PP REG, the cut valve fluid pressure _{P REG} and the brake fluid pressure _{P FL, P RR, P RL} , P FR The control valve means V, the cut valve 6 and the suction valve 7 are determined and driven, and the control valve means drive portion 23a for driving the control valve means V and the cut valve drive portion 23b for driving the cut valve 6 are used. And a suction valve drive unit 23c for driving the suction valve 7.

The motor drive unit 24, the motor based on the target fluid pressure _{PP FL, PP RR, PP RL} , PP FR, PP REG, the cut valve fluid pressure _{P REG} and the brake fluid pressure _{P FL, P RR, P RL} , P FR The number of rotations of 9 is determined and driven. That is, the motor drive unit 24 drives the motor 24 by rotation speed control. In the present embodiment, the rotation speed control is performed by duty control.

Here, the drive control by the motor drive unit 24 will be described in more detail.
FIG. 4A is a graph showing the change over time of the target hydraulic pressure and the brake hydraulic pressure of the wheel brake, and FIG. 4B is a graph showing the change over time of the duty ratio of the motor.
As shown in FIG. 4, first, at the time of the elapsed time t ₁ is started behavior stabilization control of the vehicle CR by the vehicle brake hydraulic pressure control unit 100, the difference between the brake fluid pressure P and the target fluid pressure PP is α If less than (PP-P <α, PP> P, between elapsed times t _{1 and} t ₂ ), the motor drive unit 24 causes the motor 9 to rotate at a rotational speed smaller than the maximum rotational speed, which is a low duty ratio in this embodiment. And the duty ratio of the motor 9 is adjusted so that the brake fluid pressure P follows the target fluid pressure PP. When the difference between the brake fluid pressure P and the target fluid pressure PP is greater than or equal to α (PP−P ≧ α, PP> P, elapsed time t _{2 to} t ₃ ), the motor drive unit 24 turns the motor 9 Driving is performed at the maximum number of revolutions, in this embodiment, a duty ratio of 100%. When the difference between the brake fluid pressure P and the target fluid pressure PP becomes less than α (PP−P <α, PP> P, between the elapsed times t _{3 and} t ₄ ), the motor driving unit 24 turns the motor 9 The duty ratio of the motor 9 is adjusted so that the brake hydraulic pressure P follows the target hydraulic pressure PP while being driven at a lower rotational speed than the maximum rotational speed, in this embodiment, a low duty ratio. At this time, the motor drive unit 24 performs control so that the brake fluid pressure P does not exceed the target fluid pressure PP, that is, the brake fluid pressure P follows the target fluid pressure PP while maintaining the target fluid pressure PP or lower. Do.
Therefore, the vehicle brake fluid pressure control apparatus 100 maintains the boosting performance by the pump 4 as compared with the conventional apparatus in which the motor 9 is driven at a duty ratio of 100% for a predetermined time and then driven at a low duty ratio. 9 operating noise can be suppressed.
Such control can be applied to the one having the maximum target hydraulic pressure among the four wheel brakes FL, RR, RL, FR.

FIG. 5 is a graph showing an example of pulsation returning to the cut valve, (a) is a graph showing a case where the motor is driven at a duty ratio of 100%, and (b) is a case where the motor is driven at a low duty ratio. It is a graph which shows. In each graph, the vertical axis represents the brake fluid pressure (cut valve fluid pressure) acting on the cut valve 6, the horizontal axis represents the elapsed time, and the scale of each axis in both graphs is the same.
As shown in FIGS. 5 (a) and 5 (b), it can be seen that driving the motor 9 with a low duty ratio reduces the pulsation returning to the cut valve 6 as compared with driving with a duty ratio of 100%. That is, when the difference between the brake fluid pressure P and the target fluid pressure PP is greater than or equal to α, the motor 9 is driven at a duty ratio, and when the difference between the brake fluid pressure P and the target fluid pressure PP is less than α, the motor 9 is driven at a low duty. By driving at a ratio, the pulsation transmitted to the cut valve 6 can be suppressed while maintaining the boosting performance to reduce the operating noise of the cut valve 6 and the operating noise of the motor 9 can be reduced.

Next, motor drive processing by the control device 20 will be described.
FIG. 6 is a flowchart showing motor drive processing by the control device.
As shown in FIG. 6, first, the control device 20 determines whether or not behavior stabilization control is being executed (step S1).
When the behavior stabilization control is being executed (Yes in step S1), the difference between the target hydraulic pressure of each wheel brake and the brake hydraulic pressure (the value obtained by subtracting the brake hydraulic pressure from the target hydraulic pressure) is calculated, and predetermined Compared with the value α (steps S2, S3, S4, S5).
When the difference between the target hydraulic pressure of each wheel brake and the brake hydraulic pressure is less than a predetermined value α (PP−P <α, where the target hydraulic pressure PP is higher than the brake hydraulic pressure P in at least one wheel brake). It should be noted that during execution of the behavior stabilization control in this embodiment, the target hydraulic pressure PP is higher than the brake hydraulic pressure P in all wheel brakes) (steps S2, S3, S4, S5). The control device 20 drives the motor 9 with a low duty ratio (No in step S6). Here, the control device 20 drives the motor 9 so that the brake fluid pressure follows the target fluid pressure for the wheel brakes FL, RR, RL, FR having the largest target fluid pressure.
Further, if any of the differences between the target hydraulic pressure and the brake hydraulic pressure of each wheel brake FL, RR, RL, FR is equal to or greater than a predetermined value α (in any of steps S2, S3, S4, S5) Yes), the control device 20 drives the motor 9 with a duty ratio of 100% (step S7).
When the behavior stabilization control is not executed (No in step S1), the control device 20 stops the motor 9 (step S8).

According to the vehicle brake hydraulic pressure control apparatus 100 described above, the following effects can be obtained.
When the difference between the brake fluid pressure P and the target fluid pressure PP is greater than or equal to α, the motor 9 is driven at a duty ratio of 100%. When the difference between the brake fluid pressure P and the target fluid pressure PP is less than α, the motor 9 is driven at a low duty. By driving at a ratio, it is possible to suppress operating noise and pulsation while maintaining the boosting performance of the pump 4.
When the motor 9 is driven at a low duty ratio, the wheel brake FL, FR, RL, RR is driven so that the brake fluid pressure having the maximum target fluid pressure follows the target fluid pressure. The brake fluid pressure can be controlled by driving the motor 9. Moreover, the drive amount (rotation speed) of the motor 9 can be suppressed to the minimum necessary, and the operating noise and pulsation can be further suppressed.
Since the brake fluid pressure in each wheel brake FL, FR, RL, RR is estimated, the number of pressure sensors can be reduced.
Since the rotational speed control of the motor 9 is performed by duty control, the motor drive can be controlled easily and accurately.

As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, A design change is possible suitably in the range which does not deviate from the summary of this invention .

It is a lineblock diagram of vehicles provided with a brake fluid pressure control device for vehicles concerning an embodiment of the present invention. It is a brake fluid pressure circuit diagram of a brake fluid pressure control device for vehicles. It is a block block diagram of a control apparatus. (A) is a graph which shows the time change of the target hydraulic pressure of a wheel brake, and a brake hydraulic pressure, (b) is a graph which shows the time change of the duty ratio of a motor. FIG. 5 is a graph showing an example of pulsation returning to the cut valve, (a) is a graph showing a case where the motor is driven at a duty ratio of 100%, and (b) is a case where the motor is driven at a low duty ratio. It is a graph which shows. FIG. 6 is a flowchart showing motor drive processing by the control device.

Explanation of symbols

4 Pump 6 Cut valve (Linear solenoid valve)
DESCRIPTION OF SYMBOLS 8 Pressure sensor 9 Motor 21 Target hydraulic pressure setting part 22 Brake hydraulic pressure calculation part 23 Valve drive part 24 Motor drive part 100 Brake hydraulic pressure control apparatus for vehicles FL, FR, RL, RR Wheel brake M Master cylinder (hydraulic pressure supply means )
V Control valve means

Claims (4)

A brake hydraulic pressure control device for a vehicle, wherein one hydraulic pressure path connected to hydraulic pressure supply means is connected to a plurality of wheel brakes, and the brake hydraulic pressures of the plurality of wheel brakes are controlled to respective target hydraulic pressures. ,
A linear solenoid valve provided in the one hydraulic pressure path;
A pump capable of pressurizing the brake hydraulic pressure on the wheel brake side with respect to the linear solenoid valve in the one hydraulic pressure path;
A motor capable of controlling the rotational speed for driving the pump;
A motor drive unit that drives and controls the motor by rotational speed control;
A target hydraulic pressure setting unit for setting a target hydraulic pressure of each wheel brake;
Brake fluid pressure acquisition means for acquiring the brake fluid pressure of each wheel brake;
With
The motor drive unit performs the rotation speed control of the motor by duty control, and when the vehicle behavior stabilization control is started, drives the motor at a rotation speed smaller than the maximum rotation speed, and subsequently, During the execution of the behavior stabilization control, the wheel brake having the maximum target hydraulic pressure among the wheel brakes is selected, and the target hydraulic pressure is larger than the brake hydraulic pressure in the selected wheel brake, When the difference exceeds a predetermined value, the motor is always driven at a duty ratio of 100% so as to reach the maximum rotation speed. Subsequently, during the execution of the behavior stabilization control, the selected wheel When the target hydraulic pressure is greater than the brake hydraulic pressure and the difference is less than a predetermined value in braking, the motor is driven at a rotational speed smaller than the maximum rotational speed. Vehicle brake hydraulic pressure control apparatus which is characterized in that. A brake hydraulic pressure control device for a vehicle, wherein one hydraulic pressure path connected to hydraulic pressure supply means is connected to a plurality of wheel brakes, and the brake hydraulic pressures of the plurality of wheel brakes are controlled to respective target hydraulic pressures. ,
A linear solenoid valve provided in the one hydraulic pressure path;
A pump capable of pressurizing the brake hydraulic pressure of the hydraulic pressure path on the wheel brake side from the linear solenoid valve;
A motor capable of controlling the rotational speed for driving the pump;
A motor drive unit that drives and controls the motor by rotational speed control;
A target hydraulic pressure setting unit for setting a target hydraulic pressure of each wheel brake;
Brake fluid pressure acquisition means for acquiring the brake fluid pressure of each wheel brake;
With
The motor drive unit performs the rotation speed control of the motor by duty control, and when the vehicle behavior stabilization control is started, drives the motor at a rotation speed smaller than the maximum rotation speed, and subsequently, During execution of the behavior stabilization control, the wheel brake having the maximum target hydraulic pressure is selected from at least one of the wheel brakes, and the target hydraulic pressure is higher than the brake hydraulic pressure in the selected wheel brake. When the difference is greater than or equal to a predetermined value, the motor is always driven at a duty ratio of 100% so as to be the maximum rotational speed, and then the selected during the execution of the behavior stabilization control. greater than the target hydraulic pressure is the brake fluid pressure in the wheel brakes, and when the difference is less than the predetermined value in all of the wheel brake, The serial vehicle brake hydraulic pressure control apparatus characterized by driving the motor with a small rotational speed than the maximum speed. The said motor drive part drives so that the said brake hydraulic pressure may follow the said target hydraulic pressure in the selected wheel brake, when driving the said motor with the said small rotation speed. Alternatively, the vehicle brake hydraulic pressure control device according to claim 2. The vehicle brake fluid pressure control device according to any one of claims 1 to 3, wherein the brake fluid pressure acquisition unit acquires an estimated brake fluid pressure of each wheel brake.

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