JP4913681B2 - 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 capable of increasing a brake fluid pressure applied to a wheel brake by a pump.

  Recent vehicle brake fluid pressure control devices are equipped with an electric pump, and by supplying brake fluid pressurized by the pump to the wheel brake, the driver actively controls the brake pedal even when the brake pedal is not operated. Some generate power. Such a vehicular brake hydraulic pressure control device realizes automatic braking and vehicle attitude control by generating braking force by itself.

  In such a device, when the brake fluid pressure is increased by the pump, in order to improve the response of the brake fluid pressure, more current than usual may be supplied at the beginning of the motor start (patent) Reference 1).

JP-A-4-331653

However, when the current supplied to the motor is increased, a large pulsation occurs in the discharge pressure of the pump.
Therefore, the brake fluid may slightly flow backward to the brake pedal at the moment when a large pressure is generated by pulsation. In other words, when supplying brake fluid to the wheel brake side by the pump, the brake fluid is closed at a pressure corresponding to the supplied voltage to prevent the brake fluid from escaping to the master cylinder side. Although the linear solenoid valve to be suppressed is used, if this valve is controlled according to the target pressure, the brake fluid may flow backward to the master cylinder side when the pulsation generated by the pump is high.

  Such a reverse flow hinders rapid pressure increase on the wheel brake side and unnecessarily rotates the motor fast and long, causing noise and vibration.

  The present invention has been made in view of such a background, and provides a vehicle brake hydraulic pressure control device capable of quickly increasing the hydraulic pressure path on the wheel brake side and reducing the operating noise of the motor. The task is to do.

  In order to solve the above-described problems, the present invention allows the brake fluid from the hydraulic pressure source to flow toward the wheel brake, and the hydraulic pressure source from the wheel brake side at a pressure corresponding to the input current. A pressure regulating valve that suppresses the flow of the brake fluid to the side, a pump that pressurizes the brake fluid and discharges the fluid to the fluid pressure path on the wheel brake side of the pressure regulating valve, a motor that drives the pump, A vehicular brake hydraulic pressure control device that controls driving and duty-controls a current flowing through the pressure regulating valve according to a target hydraulic pressure of the wheel brake, wherein the control device is an initial drive of the motor Sometimes, regardless of the target hydraulic pressure, the switching valve is controlled at a duty ratio higher than a duty ratio determined from the target hydraulic pressure for a first predetermined time. .

According to such a vehicle brake hydraulic pressure control device, the pressure regulating valve is controlled at a duty ratio higher than the duty ratio determined from the target hydraulic pressure regardless of the target hydraulic pressure during the first predetermined time. . In other words, since the pressure regulating valve is controlled to close with a force stronger than usual, even if a high hydraulic pressure is temporarily generated due to the pulsation of the pump, the brake fluid from the wheel brake side to the hydraulic pressure source side is controlled. Leakage can be suppressed and the pressurization efficiency of the wheel brake by the pump can be improved.
In the present invention, the initial driving of the motor means when the stopped motor suddenly starts rotating or when the motor that has been rotating at low speed suddenly starts rotating at high speed.

In the vehicular brake hydraulic pressure control device according to the present invention, the control device duty-controls the motor according to the target hydraulic pressure, and during the initial drive, the second predetermined time regardless of the target hydraulic pressure. between the you drive the motor at a higher duty ratio than the duty ratio determined from the target fluid pressure.

Thus, during initial driving of the motor, during the second predetermined time when controlling the motor at a higher duty ratio than the duty ratio determined from the target fluid pressure, the pulsation of the motor increases, the motor The present invention is particularly effective in that the brake fluid can be prevented from flowing back to the hydraulic pressure source side as the pump outlet pressure exceeds the target hydraulic pressure due to driving at a high duty ratio .

  In the above-described vehicle brake hydraulic pressure control device, for example, the first predetermined time is determined according to the target hydraulic pressure and the rotational speed of the motor.

  Thereby, the first predetermined time can be appropriately determined, and the brake fluid pressure of the wheel brake can be quickly controlled to an appropriate pressure.

  According to the present invention, even when the pulsation of the brake fluid pressure occurs during the initial driving of the motor, the leakage of the brake fluid to the fluid pressure source side is suppressed, and the fluid pressure path on the wheel brake side can be quickly pressurized. Reduction of motor operating noise can be realized.

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 hydraulic pressure control device 100 is for appropriately controlling a braking force (brake hydraulic pressure) applied to each wheel W of the vehicle CR, and an oil passage (hydraulic pressure passage). And a hydraulic unit 10 provided with various components, and a control device 20 for appropriately controlling various components in the hydraulic unit 10. 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 W, 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 W. 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 vehicular brake hydraulic pressure control device 100 includes a master cylinder M that is a hydraulic pressure source that generates a brake hydraulic pressure corresponding to a pedaling force applied to the brake pedal BP by the driver, It arrange | positions between wheel brakes FR, FL, RR, RL. The hydraulic unit 10 includes a pump body 10a that is a base body having an oil passage through which brake fluid flows, a plurality of inlet valves 1 and outlet valves 2 arranged on the oil passage. 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 wheel 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.

  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 includes a reservoir 3, a pump 4, a damper 5, an orifice 5a, a pressure regulator (regulator) R, a suction valve 7, and a storage chamber 7a in each of the first system and the second system. ing. The hydraulic unit 10 is provided with a common motor 9 for driving the first system pump 4 and the second system pump 4. 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 passages from the output ports M1, M2 of the master cylinder M to the pressure regulating valves R are referred to as “output hydraulic pressure passages A1,” and the oil from the first system pressure regulating valve R to the wheel brakes FL, RR. The oil passages from the road and the second system pressure regulating valve 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”.

  The control valve means V is a valve that controls the flow of hydraulic pressure from the master cylinder M or the pump 4 side to the wheel brakes FL, RR, RL, FR side (specifically, the wheel cylinder H side). The pressure can be increased, held or decreased. Therefore, the control valve means V 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 W is about to be locked, so that the brake hydraulic pressure transmitted from the brake pedal BP to each wheel brake FL, FR, RL, RR is cut off. .

  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 W 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 flow 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 brake fluid absorbed by the reservoir 3 can be returned to the master cylinder M, and the brake fluid pressure is generated instead of the operation of the brake pedal BP, as will be described later. , RR, RL, FR can generate braking force.
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 pressure regulating valve R described later by the cooperative action.

  The pressure regulating valve R permits the flow of brake fluid from the output hydraulic pressure path A1 to the wheel hydraulic pressure path B during normal times, and increases the pressure on the wheel cylinder H side by the brake hydraulic pressure generated by the pump 4. It has a function of adjusting the pressure on the wheel hydraulic pressure path B and the wheel cylinder H side to a set value or less while blocking the flow, and includes a switching valve 6 and a check valve 6a.

The switching 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. . Although not shown in detail, the valve body of the switching valve 6 is urged toward the wheel hydraulic pressure path B and the wheel cylinder H by the electromagnetic force corresponding to the applied current, and the pressure of the wheel hydraulic pressure path B is output. When the pressure in the hydraulic pressure path A1 is higher than a predetermined value (this predetermined value depends on the applied current), the brake fluid escapes from the wheel hydraulic pressure path B to the output hydraulic pressure path A1, The pressure on the wheel hydraulic pressure passage B side is adjusted to a predetermined pressure.
The current applied to the switching valve 6 is controlled by duty control.

  The check valve 6a is connected to each switching 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. When the switching valve 6 is closed, in other words, when the brake fluid pressure is applied to each wheel brake FL, FR, RL, RR during non-pedal operation, the intake valve 7 is opened (opened) by the control of the control device 20. Is done.

  The storage chamber 7 a is provided between the pump 4 and the suction valve 7 on the suction fluid pressure path C. 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 input to the control device 20.

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 switching valve 6 and the suction valve 7 in the hydraulic unit 10 based on signals input from the sensors 91 to 95 and the pressure sensor 8. In addition, the operation of the motor 9 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, a motor driving unit 24, a timer 28, and a storage unit 29 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 sets the target hydraulic pressure of each wheel brake FL, RR, RL, FR according to the control logic. . 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 W. 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 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 pressure of the wheel cylinder H, the target hydraulic pressure of each wheel brake FL, RR, RL, FR can be set.

Further, the target hydraulic pressure setting unit 21 compares the same system among the target hydraulic pressures of the wheel brakes FL, RR, RL, FR, and among these, the highest target hydraulic pressure is set to the wheel in the system. The target hydraulic pressure of cylinder H is set. In principle, according to the target hydraulic pressure, the current flowing through the switching valve 6 and the motor 9, that is, the duty ratio is determined.
Each set target hydraulic pressure is output to the valve drive unit 23 and the motor drive unit 24 as appropriate.

  The brake fluid pressure calculation unit 22 is configured to detect the wheel brakes FL, RR, The brake fluid pressure (estimated brake fluid pressure) of RL and FR is calculated. The calculated estimated brake fluid pressure is output to the valve drive unit 23 and the motor drive unit 24.

The valve drive unit 23 is configured so that the brake fluid pressures of the wheel cylinders H of the wheel brakes FL, RR, RL, FR are equal to the target fluid pressure set by the target fluid pressure setting unit 21. A pulse signal for operating the inlet valve 1, the outlet valve 2, the switching valve 6 and the suction valve 7 is output to the hydraulic unit 10. For example, as the difference between the current brake hydraulic pressure of the wheel cylinder H and the target hydraulic pressure is larger, more pulses are output from the pulse signal.
The valve drive unit 23 determines and drives the control valve means V, the switching valve 6 and the intake valve 7 based on each target hydraulic pressure and each estimated brake hydraulic pressure, and drives the control valve means V. A control valve means driving unit 23 a for controlling the pressure regulating valve R, and a suction valve driving unit 23 c for driving the suction valve 7.

  When the pressure of the wheel cylinder H is to be increased from the difference between the target hydraulic pressure and the estimated brake hydraulic pressure calculated by the brake hydraulic pressure calculation unit 22, the control valve means driving unit 23a has an inlet valve 1 and an outlet valve 2 Do not pass current to both. On the other hand, when the pressure of the wheel cylinder H is to be decreased, a pulse signal is sent to both the inlet valve 1 and the outlet valve 2, the inlet valve 1 is closed, and the outlet valve 2 is opened. The liquid is discharged from the outlet valve 2. When the pressure is reduced after being increased by the pump 4, the pressure is reduced by adjusting the current of the pressure regulating valve R by a pressure regulating valve drive unit 23b described later.

  The pressure regulating valve drive unit 23b determines the current to flow through the pressure regulating valve R according to the target hydraulic pressure set by the target hydraulic pressure setting unit 21, and determines the duty ratio from the determined current. For example, a map showing the relationship between the current of the pressure regulating valve R and the target hydraulic pressure as shown in FIG. 4B is stored in the storage unit 29, and the pressure regulating valve current is calculated from the target hydraulic pressure with reference to this map. That is, the duty ratio is determined.

Further, when the target hydraulic pressure rises, that is, when the pressure of the wheel cylinder H is suddenly increased (during the initial driving of the motor), the pressure regulating valve drive unit 23b causes pulsation generated by the pump 4 as a cause. A duty ratio higher than the duty ratio determined from the target hydraulic pressure (hereinafter simply referred to as “higher than normal”) for a predetermined time (first predetermined time) so that the brake fluid does not flow from the pressure regulating valve R to the master cylinder M side. A current is passed through the pressure regulating valve R at a duty ratio). For example, the pressure regulating valve drive unit 23b stores the history of the target hydraulic pressure, determines that the motor 9 is in the initial driving state when the temporal change rate of the target hydraulic pressure is higher than a certain value, During the predetermined time, a higher duty ratio is set than usual. The duty ratio higher than usual is most preferably 100%, but it may be 90% which is slightly lower than 100%.
The case where the temporal change rate of the target hydraulic pressure is high is, for example, a case where the difference between the current target hydraulic pressure and the previous target hydraulic pressure is larger than a certain value. Further, instead of the previous target hydraulic pressure, a difference from the average value of the previous several target hydraulic pressures may be taken. If there is such a change in the target hydraulic pressure, the pressure regulating valve drive unit 23b starts the timer 28, and sets the duty ratio to, for example, 100% until the timer 28 exceeds the first predetermined time.

  The first predetermined time may be a constant value, or may be increased or decreased according to the difference between the target hydraulic pressure and the estimated brake hydraulic pressure calculated by the brake hydraulic pressure calculation unit 22. For example, the first predetermined time may be decreased when the difference between the target hydraulic pressure and the estimated brake hydraulic pressure is small, and the first predetermined time may be increased when the difference is large. Further, the first predetermined time may be determined according to the target hydraulic pressure and the rotation speed of the motor 9. For example, when the rotational speed of the motor 9 is low, since the pulsation of the pressure of the hydraulic pressure passage (wheel hydraulic pressure passage B) from which the pump 4 discharged the brake fluid is small, the first predetermined time is set short. Since the pulsation is large when the number of rotations is high, the first predetermined time can be set longer.

  The suction valve drive unit 23c does not flow current to the suction valve 7 in a normal state. When the pressure of the wheel cylinder H should be increased from the target hydraulic pressure output by the target hydraulic pressure setting unit 21 and the master cylinder pressure detected by the pressure sensor 8 is insufficient, the pump 4 A pulse signal is output to the suction valve 7 to enable pressurization. As a result, the suction valve 7 is opened and the brake fluid is sucked into the pump 4 from the master cylinder M.

  The motor drive unit 24 determines and drives the number of rotations of the motor 9 based on each target hydraulic pressure. That is, the motor drive unit 24 drives the motor 9 by rotational speed control. In this embodiment, the rotational speed control is performed by duty control.

  First, the motor drive unit 24 determines the motor rotation speed according to the target hydraulic pressure set by the target hydraulic pressure setting unit 21, and determines the duty ratio from the determined motor rotation speed. For example, a map showing the relationship between the motor current and the target hydraulic pressure as shown in FIG. 4A is stored in the storage unit 29, and the motor current, that is, the duty ratio is calculated from the target hydraulic pressure with reference to this map. To decide.

  Further, when the target hydraulic pressure rises, that is, when the pressure of the wheel cylinder H is to be suddenly increased (during the initial driving of the motor), the motor driving unit 24 increases the pressure quickly. The motor 9 is driven at a duty ratio (duty ratio higher than usual) higher than the duty ratio determined from the pressure. For example, the motor drive unit 24 stores the history of the target hydraulic pressure, determines that the motor is in the initial drive when the temporal change rate of the target hydraulic pressure is higher than a certain value, and determines the predetermined time (first time). During a predetermined time (2), a higher duty ratio is set than usual. The duty ratio higher than usual is most preferably 100%, but it may be 90% which is slightly lower than 100%.

The case where the temporal change rate of the target hydraulic pressure is high is, for example, a case where the difference between the current target hydraulic pressure and the previous target hydraulic pressure is larger than a certain value. Further, instead of the previous target hydraulic pressure, a difference from the average value of the previous several target hydraulic pressures may be taken. When there is such a change in the target hydraulic pressure, the motor driving unit 24 starts the timer 28 and sets the duty ratio to, for example, 100% until the timer 28 exceeds the second predetermined time.
The second predetermined time may be a constant value, or may be increased or decreased according to the difference between the target hydraulic pressure and the estimated brake hydraulic pressure calculated by the brake hydraulic pressure calculation unit 22. For example, the second predetermined time may be decreased when the difference between the target hydraulic pressure and the estimated brake hydraulic pressure is small, and the second predetermined time may be increased when the difference is large.

  Note that the first predetermined time and the second predetermined time may be the same, but need not be the same.

The operation of the vehicular brake hydraulic pressure control device 100 configured as described above will be described focusing on the features of the present invention. FIG. 5 is a flowchart for explaining processing of the vehicle brake hydraulic pressure control device.
Here, for the sake of simplification of explanation, a case where the first predetermined time and the second predetermined time are the same will be described as an example. Therefore, the control device 20 performs part of the processing as the pressure regulating valve driving unit 23b and the processing as the motor driving unit 24 at the same time.

The control device 20 repeatedly performs the processing from the start to the end according to the flowchart shown in FIG.
First, while the vehicle CR is in progress, based on the detection results of the sensors 91 to 95, the target hydraulic pressure setting unit 21 controls vehicle behavior and anti-lock brake control that prevents the wheel brakes FL, RR, RL, FR from being locked. Is determined, and the target hydraulic pressure is set (S101).
Then, the brake fluid pressure calculation unit 22 determines the wheel brakes FL, RR, RL, based on the master cylinder pressure detected by the pressure sensor 8 and the previous drive amount of each solenoid valve 1, 2, 6 by the valve drive unit 23. FR brake fluid pressure (estimated brake fluid pressure) is calculated (S102).

  Next, the valve drive unit 23 of the control device 20 determines whether or not the target hydraulic pressure has increased rapidly based on the target hydraulic pressure history stored in the storage unit 29 (S103). As described above, this determination is made based on, for example, whether or not the difference between the current target hydraulic pressure and the average value of several previous target hydraulic pressures exceeds a certain value. If the target hydraulic pressure has increased rapidly (S103, Yes), the timer 28 is started and the elapsed time T is set to 0 (S104). Then, a flag (flag) indicating that the timer 28 is measuring time is set to 1 (S105). Also, a predetermined time Tth (here, Tth is a first predetermined time and a second predetermined time) is set. The predetermined time Tth may be a constant value or may be changed according to the difference between the target hydraulic pressure and the estimated brake hydraulic pressure.

  Next, it is determined whether the elapsed time T is longer than the predetermined time Tth (S107). When the elapsed time T is longer than the predetermined time Tth (S107, Yes), since the predetermined time Tth has elapsed, the flag is set to 0 (S108).

  Next, it is determined whether or not the flag is 1, and if it is 1 (S109, Yes), the target hydraulic pressure increases rapidly and corresponds to “at the time of initial driving of the motor”. Set to 100% (S110). Further, the duty ratio of the pressure regulating valve R is also set to 100% (S111).

On the other hand, when the flag is not 1 (S109, No), the duty ratio of the motor 9 is set from the target hydraulic pressure (S112). Further, the duty ratio of the pressure regulating valve R is set from the target hydraulic pressure (S113).
In steps S112 and S113, the estimated brake fluid pressure may be taken into consideration in order to determine the duty ratio, instead of setting only from the target fluid pressure. Further, when the duty ratio of the pressure regulating valve R is set (S113), it may be set according to the target hydraulic pressure and the rotational speed in consideration of the rotational speed (that is, the duty ratio) of the motor 9.

If the duty ratios of the motor 9 and the pressure regulating valve R are determined as described above, whether the operation is a pressure increase or a pressure decrease determined from the target hydraulic pressure, and whether or not the pump 4 is pressurized. Accordingly, the control valve means driving unit 23a drives the control valve means V, and the suction valve driving unit 23c drives the suction valve 7 (S114). Then, the pressure regulating valve drive unit 23b outputs a signal for driving the pressure regulating valve R based on the determined duty ratio to the pressure regulating valve R (S115), and the motor driving unit 24 drives the motor 9 based on the determined duty ratio. A signal is output to the motor 9 (S116). As a result, the motor 9 rotates, and the rotation of the motor 9 causes the pump 4 to discharge the brake fluid to the wheel hydraulic pressure passage B, and the pressure regulating valve R brakes from the wheel hydraulic pressure passage B to the master cylinder M side at a predetermined pressure. Suppress the flow of liquid.
Then, the timer is counted (S117), and the processing from step S101 is repeated.

Even if the discharge pressure of the pump 4 fluctuates violently due to the motor 9 rotating at a high rotation speed during the initial driving of the motor 9 by the above processing, the pressure regulating valve R Is driven at 100% duty, so that the flow of brake fluid from the wheel hydraulic pressure path B to the master cylinder M side can be suppressed as much as possible, and the hydraulic pressure of the wheel cylinder H can be quickly increased. Furthermore, since the hydraulic pressure of the wheel cylinder H increases rapidly, the high-speed rotation time of the motor 9 can be shortened, and the sensible motor operating noise can be reduced.
In the above processing example, the case where the first predetermined time and the second predetermined time are the same has been described. However, when the first predetermined time and the second predetermined time are different, the predetermined time is Two flags (flag in FIG. 5) indicating whether or not it is in progress, a variable for obtaining time from the timer 28 (T in FIG. 5), and a threshold value to be compared with this variable (Tth in FIG. 5) are prepared. According to each value, conditions may be divided in the same manner as the flow of FIG.

The result of such processing will be described with reference to the time chart of FIG. 6A is a time chart of hydraulic pressure, FIG. 6B is a time chart of pressure regulating valve current, and FIG. 6C is a time chart of motor rotation speed.
In FIG. 6A, the temporal change in the target hydraulic pressure is indicated by a broken line, the caliper pressure (estimated brake hydraulic pressure) is indicated by a thick solid line, and the pump outlet pressure, that is, the pressure of the discharge hydraulic pressure path D is indicated by a thin solid line. Show. In FIG.6 (b), the example of control of the pressure regulation valve R of this embodiment is shown as the continuous line, and the example of control of the conventional pressure regulation valve R is shown with the dashed-two dotted line.

  As shown in FIG. 6A, for example, at the time t0, the target hydraulic pressure increases rapidly depending on the traveling state of the vehicle CR. Due to the rapid increase in the target hydraulic pressure, the motor driving unit 24 drives the motor 9 with a higher duty ratio than usual for the second predetermined time, as shown in FIG. In FIG. 6, the pressure of the wheel cylinder H is increased at time t <b> 0 to t <b> 2, and during this period, time t <b> 0 to t <b> 1 is the initial driving time of the motor 9. Further, the pressure regulating valve drive unit 23b also drives the pressure regulating valve R with 100% duty as shown in FIG. 6 (b).

  In the conventional control, the current of the pressure regulating valve R is set according to the target hydraulic pressure. That is, if the pressure in the wheel hydraulic pressure passage B exceeds the target hydraulic pressure, the excess brake fluid is set to flow to the master cylinder M side. For this reason, the temporal change in the pressure regulating valve current is similar to the change in the target hydraulic pressure.

  By the way, when the motor 9 is driven at a higher duty ratio than usual, the pump outlet pressure pulsates violently, and instantaneously exceeds the target hydraulic pressure as shown in FIG. When such a high hydraulic pressure is generated, conventionally, a part of the brake fluid flows to the master cylinder M side by an amount exceeding the target hydraulic pressure. However, as indicated by the solid line in FIG. 6A, when the motor 9 is initially driven, the caliper pressure has not yet reached the target hydraulic pressure, and it is not necessary to flow the brake fluid to the master cylinder M side. I can say that.

Therefore, in the present embodiment, as shown in FIG. 6B, the pressure regulating valve R is increased as much as possible (by increasing the duty ratio) as much as possible when the motor 9 is initially driven to increase the pressure regulating valve R as much as possible. Is closed to prevent the brake fluid from flowing to the master cylinder M side. Therefore, the caliper pressure increases quickly and can reach the target hydraulic pressure quickly.
Moreover, as a result of the caliper pressure increasing rapidly, the time for driving the motor 9 with a higher duty ratio than usual can be shortened, and the sensible operating noise can be reduced.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and can be appropriately changed in design without departing from the gist of the present invention.
For example, the hydraulic pressure source is not limited to the master cylinder M that generates pressure by the brake pedal BP. Further, the pressure regulating valve referred to in the present invention may be a valve that blocks the flow of brake fluid from the hydraulic pressure path on the discharge side of the pump to the hydraulic pressure source side, and may be called another name.
Further, the flowchart of FIG. 5 shows an example, and other processing methods can be employed.

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 map showing the relationship between the motor current and the target hydraulic pressure, and (b) is a map showing the relationship between the pressure regulating valve current and the target hydraulic pressure. It is a flowchart explaining the process of the brake fluid pressure control apparatus for vehicles. (A) is a time chart of hydraulic pressure, (b) is a time chart of pressure regulating valve current, and (c) is a time chart of motor rotation speed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inlet valve 2 Outlet valve 4 Pump 6 Switching valve 7 Suction valve 8 Pressure sensor 9 Motor 10 Fluid pressure unit 20 Control apparatus 21 Target fluid pressure setting part 22 Brake fluid pressure calculation part 23 Valve drive part 23a Control valve means drive part 23b Control Pressure valve drive unit 23c Suction valve drive unit 24 Motor drive unit 28 Timer 29 Storage unit 100 Brake fluid pressure control device for vehicle FL, RR, RL, FR Wheel brake H Wheel cylinder M Master cylinder R Pressure regulating valve

Claims (2)

A pressure regulating valve that allows the brake fluid from the hydraulic pressure source to flow toward the wheel brake and suppresses the flow of the brake fluid from the wheel brake side to the hydraulic pressure source side with a pressure corresponding to the input current. When,
A pump that pressurizes the brake fluid and discharges it to the hydraulic pressure path on the wheel brake side from the pressure regulating valve;
A motor for driving the pump;
Brake hydraulic pressure for a vehicle comprising: a control device that controls the drive by duty-controlling the motor according to the target hydraulic pressure of the wheel brake and duty-controlling the current flowing through the pressure regulating valve according to the target hydraulic pressure of the wheel brake A control device,
The control device controls the pressure regulating valve at a duty ratio higher than a duty ratio determined from the target hydraulic pressure during a first predetermined time regardless of the target hydraulic pressure during initial driving of the motor ; and During the initial drive of the motor, the motor is driven at a duty ratio higher than the duty ratio determined from the target hydraulic pressure for a second predetermined time regardless of the target hydraulic pressure, thereby A brake fluid pressure control apparatus for a vehicle, wherein the brake fluid is prevented from flowing back to the fluid pressure source side because the pump outlet pressure exceeds the target fluid pressure due to driving at a high duty ratio . 2. The vehicle brake hydraulic pressure control device according to claim 1 , wherein the first predetermined time is determined according to the target hydraulic pressure and a rotation speed of the motor.

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