JP5783946B2 - Brake hydraulic pressure control device for vehicles - Google Patents

Description

  The present invention relates to a vehicle brake fluid pressure control device including a pump capable of increasing brake fluid pressure.

  Conventionally, as a brake fluid pressure control device for a vehicle that compensates for the failure of the booster, when the booster fails, the brake fluid pressure is increased by the pump of the vehicle brake fluid pressure control device. The structure which was made is disclosed (refer patent document 1). Specifically, in this technology, when the booster has failed while the vehicle is running, the boost control is performed to increase the brake fluid pressure with the pump while the driver is stepping on the brake. ing.

Japanese Patent Laid-Open No. 2004-217214

  However, in the above-described technology, for example, when the driver is stepping on the brake pedal continuously for a relatively long time, such as slow deceleration from a high-speed running or a long downhill, the pump continues to drive, There exists a subject that the power consumption by continuous drive of a pump (motor which drives a pump) will become large.

  Accordingly, the present invention suppresses the power consumption of the pump even when the driver is stepping on the brake pedal for a relatively long time in a configuration in which the brake fluid pressure is increased by the pump while the vehicle is running. An object of the present invention is to provide a vehicle brake hydraulic pressure control device that can perform the above operation.

  The present invention that solves the above-described problems is a vehicle brake hydraulic pressure control device that includes a pump that pumps brake fluid from a master cylinder and can increase the hydraulic pressure of a wheel brake so that the hydraulic pressure is higher than the master cylinder pressure. An acquisition unit that acquires a related parameter related to the requested deceleration requested by the driver, and a boosting unit that operates the pump based on the related parameter to increase the hydraulic pressure of the wheel brake. The pressure raising means holds the hydraulic pressure of the wheel brake and stops the pump when the related parameter is constant for a predetermined time or more during traveling of the vehicle.

  Here, “the related parameter is constant for a predetermined time or more” means that the related parameter is substantially constant for a predetermined time (contains within a narrow range).

  According to this configuration, when the related parameter is constant for a predetermined time or more during traveling of the vehicle, the booster maintains the wheel brake fluid pressure and stops the pump, so that the driver is relatively long. Even when the brake pedal is stepped on continuously, the power consumption of the pump can be suppressed.

  In the above configuration, it is preferable that the acquisition unit acquires the master cylinder pressure as the related parameter.

  According to this, since the master cylinder pressure directly connected to the brake fluid pressure is acquired as a related parameter, for example, compared to a mode in which the stroke amount of the brake pedal is acquired as a related parameter, it is more accurate without being affected by play or the like. The pump can be controlled.

  Further, in the configuration described above, an estimated wheel cylinder pressure calculating unit that calculates the hydraulic pressure of the wheel brake as an estimated wheel cylinder pressure based on a past control history, and a filter process is performed on the estimated wheel cylinder pressure. Filter processing means for calculating an estimated wheel cylinder pressure filter value and requested wheel cylinder pressure calculating means for calculating a requested wheel cylinder pressure based on at least the master cylinder pressure, wherein the pressure raising means comprises the estimated wheel. When the state where the deviation amount between the cylinder pressure filter value and the required wheel cylinder pressure is equal to or less than a predetermined value continues for the predetermined time, the related parameter is determined to be constant for a predetermined time or more. Is desirable.

  According to this, the difference between the requested wheel cylinder pressure calculated from the master cylinder pressure and the value obtained by delaying the estimated wheel cylinder pressure calculated from information other than the master cylinder pressure is compared, and the related parameter is constant for a predetermined time or more. Therefore, it is possible to make a determination based on the wheel cylinder pressure actually requested by the driver as compared with, for example, a mode in which it is determined whether the master cylinder pressure is constant for a predetermined time or more. it can.

  In the above-described configuration, the estimated wheel cylinder pressure calculating unit calculates an estimated wheel cylinder pressure for each wheel brake corresponding to two front wheels, and the boosting unit calculates the estimated wheel cylinder pressure filter value as the estimated wheel cylinder pressure filter value. It is desirable to use a value corresponding to the smaller estimated wheel cylinder pressure of the two estimated wheel cylinder pressures calculated by the estimated wheel cylinder pressure calculating means.

  According to this, the value corresponding to the smaller estimated wheel cylinder pressure of the two front wheels that greatly contributes to the braking force is used as the estimated wheel cylinder pressure filter value, and the larger one is used as the estimated wheel cylinder pressure filter value. Compared to the configuration used, the time until the deviation between the estimated wheel cylinder pressure filter value and the required wheel cylinder pressure falls below the specified value is longer, and the time required for pressure increase control is longer. Can be high.

  Further, in the configuration described above, the required wheel cylinder pressure calculating means for calculating the required wheel cylinder pressure based on at least the master cylinder pressure, and the required wheel cylinder pressure filter by performing a filtering process on the required wheel cylinder pressure. Filter processing means for calculating a value, and the boosting means continues for a predetermined time when a deviation amount between the required wheel cylinder pressure filter value and the required wheel cylinder pressure is equal to or less than a predetermined value. In this case, the related parameter may be determined to be constant for a predetermined time or more.

  Even in this case, it can be determined whether the related parameter is constant for a predetermined time or more.

  The above-described configuration further includes a determination unit that determines whether or not the booster is normal, and the boosting unit determines that the related parameter when the determination unit determines that the booster is not normal. It is desirable to be configured to control the pump based on

  According to this, in the fail-safe control in which the brake fluid pressure is increased by the pump when it is determined that the booster is not normal, the driver is stepping on the brake pedal continuously for a relatively long time. However, the power consumption of the pump can be suppressed by maintaining the hydraulic pressure of the wheel brake and stopping the pump.

  According to the present invention, in a configuration in which the brake fluid pressure is increased by the pump while the vehicle is running, the power consumption of the pump is suppressed even when the driver steps on the brake pedal continuously for a relatively long time. be able to.

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 diagram which shows the structure of a control part. It is a map which shows the relationship between a master cylinder pressure and a request | requirement regulator pressure. It is a flowchart which shows operation | movement of the control part at the time of abnormality of a brake booster. It is a flowchart which shows a control mode selection process. It is a time chart which shows an example of changes, such as an operation state of each component at the time of abnormality of a brake booster, and required caliper pressure.

Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
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 unit 20 for appropriately controlling various components in the hydraulic unit 10. In addition, a pressure sensor 30, a negative pressure chamber pressure sensor 40, and a wheel speed sensor 50, which are examples of acquisition means, are connected to the control unit 20 of the vehicle brake hydraulic pressure control device 100. The signal from is input.

  The pressure sensor 30 is a sensor that detects (acquires) a pressure in the master cylinder MC (hereinafter also referred to as a master cylinder pressure) as an example of a related parameter related to the requested deceleration requested by the driver, and will be described later. It is provided in the hydraulic unit 10 (see FIG. 2).

  The negative pressure chamber pressure sensor 40 is a sensor that detects the pressure in the negative pressure chamber of a brake booster BB as an example of a booster, and is provided between the master cylinder MC and the brake pedal BP.

  The wheel speed sensor 50 is a sensor that detects the wheel speed of the wheel W, and is provided in each wheel W.

  The control unit 20 includes, for example, a CPU, a RAM, a ROM, and an input / output circuit, and performs each arithmetic processing based on inputs from the sensors 30 to 50 and programs and data stored in the ROM. Execute control.

  The caliper CA is a hydraulic pressure that converts the brake hydraulic pressure generated by the master cylinder MC and the vehicle brake hydraulic 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. In this embodiment, the wheel cylinder pressure is described as the caliper pressure.

  As shown in FIG. 2, the hydraulic unit 10 of the vehicular brake hydraulic pressure control device 100 includes a master cylinder MC that is a hydraulic pressure source that generates a brake hydraulic pressure in accordance with the 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 MC 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 is provided with a reservoir 3, a pump 4, an orifice 5a, a pressure regulating valve (regulator) R, and a suction valve 7 in each of the first system and the second system. 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 following, the oil passages from the output ports M1 and M2 of the master cylinder MC to the respective 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 and 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 MC or the pump 4 to the wheel brakes FL, RR, RL, FR (specifically, caliper CA), and increases the pressure of the caliper CA. Can be held or lowered. 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 proportional solenoid valve provided between each wheel brake FL, RR, RL, FR and the master cylinder MC, that is, in the wheel hydraulic pressure passage B. Therefore, the differential pressure upstream and downstream of the inlet valve 1 can be adjusted according to the value of the drive current flowing through the inlet valve 1.

  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 unit 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 MC side, and when the input from the brake pedal BP is released, Even when the valve 1 is closed, inflow of brake fluid from each wheel brake FL, FR, RL, RR side to the master cylinder MC side is allowed.

  The reservoir 3 is provided in the release path E, and has a function of storing 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 that communicates with the output hydraulic pressure path A1 and the discharge hydraulic pressure path D that communicates with the wheel hydraulic pressure path B, and supplies the brake fluid in the master cylinder MC and the reservoir 3. It has a function of inhaling and discharging to the discharge hydraulic pressure path D (wheel hydraulic pressure path B). Thus, the brake fluid absorbed by the reservoir 3 can be returned to the master cylinder MC, and the brake fluid pressure is generated regardless of whether or not the brake pedal BP is operated, as will be described later, and the wheel brakes FL, RR, A braking force can be generated in RL and FR.

  Specifically, the pump 4 pumps the brake fluid from the master cylinder MC or the like so that the hydraulic pressure of the wheel brakes FL, RR, RL, and RR (caliper CA) is higher than the master cylinder pressure. The fluid pressures of FL, RR, RL, and RR can be increased. 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 orifice 5a attenuates the pulsation of the pressure of the brake fluid discharged from the pump 4.

  The pressure regulating valve R allows the brake fluid from the master cylinder MC to flow to the wheel brakes FL, RR, RL, FR at normal times, and increases the pressure on the caliper CA side by the brake fluid pressure generated by the pump 4. The function of adjusting the pressure on the caliper CA side to be equal to or lower than the set value while blocking this flow (suppressing the flow from the wheel brake FL, RR, RL, FR side to the master cylinder MC side) is provided. Specifically, the pressure regulating valve R includes a switching valve 6 and a check valve 6a.

  The switching valve 6 is a normally open proportional solenoid valve interposed between the output hydraulic pressure path A1 leading to the master cylinder MC and the wheel hydraulic pressure path B leading to each wheel brake FL, FR, RL, RR. . Therefore, the differential pressure between the upstream and downstream of the switching valve 6 is adjusted by arbitrarily changing the valve closing force according to the value of the drive current (indicated current value) input to the switching valve 6, and the wheel hydraulic pressure path The pressure of B can be adjusted below the set value.

  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. The suction valve 7 is opened by the control of the control unit 20 when the hydraulic pressure in each wheel brake FL, FR, RL, RR is increased by the pump 4, for example.

Next, details of the control unit 20 will be described.
As shown in FIG. 3, the control unit 20 is mainly based on signals input from the pressure sensor 30 and the negative pressure chamber pressure sensor 40, and the pressure regulating valve R (switching valve 6) and the suction valve 7 in the hydraulic unit 10. The operation of each wheel brake FL, RR, RL, FR is controlled by controlling the opening / closing operation and the operation of the motor 9. Specifically, the control unit 20 executes known ABS control and the like, and also performs pressure increase control by the pump 4, for example, pressure increase control by the pump 4 when the brake booster BB fails. .

  The control unit 20 includes a determination unit 21, a required caliper pressure calculation unit 22, an estimated caliper pressure calculation unit 23, a filter processing unit 24, a boosting unit 25, a motor drive unit 26, a valve drive unit 27, and a storage unit 28. ing.

  The determination means 21 has a function of determining whether or not the brake booster BB is normal based on a signal from the negative pressure chamber pressure sensor 40. Specifically, for example, the determination unit 21 determines whether or not the detection value of the negative pressure chamber pressure sensor 40 exceeds a determination threshold value, and determines that the detected value is not normal when the detection value exceeds the determination threshold value. Then, the determination unit 21 outputs the determination result to the required caliper pressure calculation unit 22 and the estimated caliper pressure calculation unit 23.

  The required caliper pressure calculating means 22 acquires the master cylinder pressure from the pressure sensor 30 when the determination result output from the determining means 21 is not normal, and based on the acquired master cylinder pressure, the required caliper pressure is calculated. It has a function to calculate pressure. Specifically, the required caliper pressure calculating means 22 calculates the required regulator pressure (target value of the differential pressure upstream and downstream of the pressure regulating valve R) based on the map MP2 and the master cylinder pressure shown in FIG.

  Here, the two types of maps MP1 and MP2 shown in FIG. 4 are stored in the storage unit 28. Of these, the first map MP1 indicated by a two-dot chain line is a map corresponding to the normal state of the brake booster BB. The master cylinder pressure and the required regulator pressure are set to coincide with each other and have a proportional relationship. In other words, the first map MP1 is a map representing the normal state of the brake booster BB, the drive current (indicated current) is not applied to the switching valve 6, and no differential pressure is generated upstream and downstream of the switching valve 6. Therefore, the master cylinder pressure and the required regulator pressure are matched.

  Further, the second map MP2 indicated by a one-dot chain line is a map corresponding to the abnormality of the brake booster BB. The second map MP2 has a proportional relationship similar to that of the first map MP1 until the relationship between the master cylinder pressure and the required regulator pressure reaches a predetermined small value P1, and thereafter increases with a larger slope than the slope of the first map MP1. It is set to be.

  Then, the required caliper pressure calculating means 22 calculates the required regulator pressure with reference to the second map MP2 from the storage unit 28, and calculates the required caliper pressure by adding the master cylinder pressure to the calculated required regulator pressure. ing. Further, the required caliper pressure calculating means 22 is configured to output the calculated required caliper pressure to the pressure increasing means 25. The required caliper pressure calculating means 22 may appropriately perform a filtering process for removing noise (hydraulic pressure pulsation by the pump 4) from the calculated required caliper pressure.

  The estimated caliper pressure calculating means 23 has a function of calculating the hydraulic pressure of the wheel brakes FL, FR, RL, RR as the estimated caliper pressure based on the past control history such as the master cylinder pressure and the control valve means V. Yes. In addition, since the calculation method of estimated caliper pressure is well-known, detailed description is abbreviate | omitted.

  The estimated caliper pressure calculating means 23 calculates the estimated caliper pressure for each of the wheel brakes FL and FR corresponding to the two front wheels, and the smaller one of the calculated two estimated caliper pressures is subjected to the filter processing means. 24 is output.

  The filter processing unit 24 has a function of calculating an estimated caliper pressure filter value by executing a filter process that delays a change in the value of the estimated caliper pressure output from the estimated caliper pressure calculating unit 23. Yes. An example of a filter process that delays the change in value is a process such as a low-pass filter.

  Then, the filter processing unit 24 outputs the calculated estimated caliper pressure filter value to the boosting unit 25.

  When the required caliper pressure and the estimated caliper pressure filter value are output from the required caliper pressure calculating unit 22 and the filter processing unit 24 (that is, the determination unit 21 determines that the brake booster BB is not normal). ), The hydraulic pressure of the wheel brakes FL, FR, RL, RR is increased by controlling the pump 4, the pressure regulating valve R, and the suction valve 7 based on the required caliper pressure (master cylinder pressure) and the estimated caliper pressure filter value.・ Has a holding function.

  Specifically, when the master cylinder pressure is constant for a predetermined time or more during traveling of the vehicle CR, the boosting means 25 controls the wheel brakes FL, FR, RL, RR by controlling the pressure regulating valve R and the intake valve 7. Holding control for holding the hydraulic pressure and stopping the pump 4 is performed. Further, when the master cylinder pressure is changing during traveling of the vehicle CR, the pressure boosting means 25 controls the pressure regulating valve R and the suction valve 7 and drives the pump 4 to drive the wheel brakes FL, FR. , RL, and RR are configured to execute boost control for increasing the hydraulic pressure.

  Here, “the master cylinder pressure is constant for a predetermined time or more” means that the master cylinder pressure is substantially constant for a predetermined time (contains within a narrow range). The booster 25 also determines whether or not the vehicle CR is traveling based on, for example, a signal from the wheel speed sensor 50.

  As a result, when the master cylinder pressure is constant for a predetermined time or more during traveling of the vehicle CR, the hydraulic pressures of the wheel brakes FL, FR, RL, RR are maintained and the pump 4 is stopped. Even when the brake pedal BP is depressed for a relatively long time, the power consumption of the pump 4 can be suppressed.

  Specifically, in the booster 25, the deviation amount between the estimated caliper pressure filter value output from the filter processor 24 and the required caliper pressure output from the required caliper pressure calculator 22 is equal to or less than a predetermined value. When the state continues for a predetermined time, the master cylinder pressure is determined to be constant for a predetermined time or more.

  This makes it possible to determine whether or not the master cylinder pressure is constant for a predetermined time or more by looking at the deviation amount between the required caliper pressure calculated from the master cylinder pressure and the estimated caliper pressure filter value calculated from information other than the master cylinder pressure. Therefore, for example, it is possible to perform the determination more accurately than in the case of simply determining whether or not the master cylinder pressure is constant for a predetermined time or more.

  Further, as described above, when the estimated caliper pressure calculating means 23 outputs the smaller one of the two estimated caliper pressures corresponding to the two front wheels, the boosting means 25 estimates as the estimated caliper pressure filter value. A value (estimated caliper pressure filter value) corresponding to the smaller estimated caliper pressure of the two estimated caliper pressures calculated by the caliper pressure calculating means 23 is used.

  By using a value corresponding to the estimated caliper pressure of the smaller one of the two front wheels that greatly contributes to the braking force in this way as the estimated caliper pressure filter value, compared to a mode in which the larger one is used as the estimated caliper pressure filter value, The time required for the deviation between the estimated caliper pressure filter value and the required caliper pressure to be less than or equal to the predetermined value becomes longer, and the time required for boost control becomes longer. It has become.

  In the boost control described above, the booster 25 outputs a motor drive signal to the motor drive unit 26, instructs the pressure regulating valve drive unit 27a to indicate an instruction current value corresponding to the required regulator pressure, and the intake valve drive unit. A signal for opening the intake valve 7 is output to 27b. Further, in the holding control described above, the boosting means 25 outputs a motor stop signal to the motor driving unit 26, instructs the pressure regulating valve driving unit 27a to indicate the command current value corresponding to the required regulator pressure, and the suction valve driving unit. A signal for closing the suction valve 7 is output to 27b.

  The motor drive unit 26 determines the number of rotations of the motor 9 based on an instruction from the booster 25 and drives it. That is, the motor drive unit 26 drives the motor 9 by rotational speed control, and performs rotational speed control by, for example, duty control.

  The valve drive unit 27 is a part that controls the pressure regulating valve R and the suction valve 7 based on an instruction from the booster 25. Therefore, the valve drive unit 27 includes a pressure regulating valve drive unit 27a and a suction valve drive unit 27b.

  The pressure regulating valve drive unit 27a does not flow current to the pressure regulating valve R during normal operation. When the command current value corresponding to the required regulator pressure is output from the booster 25, the drive current is supplied to the pressure regulating valve R according to the command current value. When a drive current is supplied to the pressure regulating valve R, a differential pressure (required regulator pressure) corresponding to the drive current can be formed upstream and downstream of the pressure regulating valve R. When a pressure difference higher than this is generated, the pressure regulating valve R Opens the valve to maintain the differential pressure according to the drive current. As a result, the hydraulic pressure in the wheel brake is regulated.

  The intake valve drive unit 27b does not flow current to the intake valve 7 at normal times or when a closing signal is output from the booster 25. When a signal for opening the intake valve 7 is output from the booster 25, a current is passed through the intake valve 7 in accordance with this signal. As a result, the suction valve 7 is opened and the brake fluid is sucked into the pump 4 from the master cylinder MC.

  The storage unit 28 stores the above-described maps MP1, MP2, and the like.

  Next, the operation of the control unit 20 when the brake booster BB is abnormal will be described in detail with reference to FIGS. The control unit 20 constantly executes the flowchart shown in FIG.

  Specifically, in the control shown in FIG. 5, the control unit 20 first determines whether or not the brake booster BB is abnormal (S1). In step S1, the control unit 20 ends this control when it is determined that there is no abnormality (No), and when it is determined that there is an abnormality (Yes), data such as the master cylinder pressure and the wheel speed are obtained. Obtain (S2).

  After step S2, the control unit 20 determines whether or not the vehicle CR is traveling (S3). In step S3, when the vehicle CR is stopped (No), the control unit 20 executes another control mode (S4) and executes this control. Here, as other control modes, there are known control modes such as a control mode corresponding to when the vehicle is stopped, a mode for prohibiting boost control, and a standby mode before entering boost control.

  In step S3, when the vehicle CR is traveling (Yes), the control unit 20 calculates the estimated caliper pressures PL and PR for the wheel brakes FL and FR corresponding to the two front wheels, respectively, and calculates the calculated right side. It is determined whether or not the estimated caliper pressure PR is equal to or less than the estimated caliper pressure PL on the left side (S5). If the left estimated caliper pressure PL is smaller than the right estimated caliper pressure PR in step S5 (No), the left estimated caliper pressure PL is selected as the estimated caliper pressure used for the subsequent control (S6).

  In step S5, when the right estimated caliper pressure PR is equal to or lower than the left estimated caliper pressure PL (Yes), the control unit 20 uses the right estimated caliper pressure PR as the estimated caliper pressure used for the subsequent control. Select (S7). After steps S6 and S7, the control unit 20 performs a filter process on the estimated caliper pressure selected in step S6 or step S7 (S8).

  After step S8, the control unit 20 calculates a required caliper pressure based on the master cylinder pressure and the map MP2 (S9), and calculates a deviation between the required caliper pressure and the estimated caliper pressure filter value (S10). After step S10, the control unit 20 executes a control mode selection process shown in FIG. 6 (S11).

  In the control mode selection process, the control unit 20 first determines whether or not the control mode is the holding mode (S21). In step S21, when the control mode is not held (No), the control unit 20 determines whether or not the deviation is equal to or less than the first threshold (S22). Here, the first threshold value can be appropriately determined by experiment, simulation, or the like.

  In step S22, when the deviation is equal to or smaller than the first threshold (Yes), the control unit 20 counts up the timer T (S23), and then determines whether or not the timer T has exceeded a predetermined time Tth. (S24). When the timer T does not exceed the predetermined time Tth in Step S24 (No), or when the deviation is larger than the first threshold value in Step S22 (No), the control unit 20 executes the boost mode as the control mode. (S25).

  In step S24, when the timer T exceeds the predetermined time Tth (Yes), the control unit 20 executes the holding mode as the control mode (S28). That is, when the deviation is constant for a predetermined time (Tth) or more (first threshold or less), the control unit 20 executes the holding mode.

  In step S21, when the control mode is the holding mode (Yes), the control unit 20 determines whether or not the deviation is larger than the second threshold (S26). Here, the second threshold value is a threshold value for switching from the holding mode to the boost mode, and can be appropriately determined by experiments, simulations, or the like. The first threshold value and the second threshold value may be different values or the same value.

  In step S26, when the deviation is larger than the second threshold (Yes), the control unit 20 shifts from the holding mode to the boost mode (S27). When it is determined No in steps S25, S28, S27, and step S26, the control unit 20 proceeds to the process of step S12 in the flowchart of FIG.

  In step S12, the control unit 20 calculates a control amount corresponding to each control mode (S12), and outputs a drive instruction to the pressure regulating valve R, the suction valve 7 and the motor 9 based on the control amount (S13). This control is finished.

Next, an example of control of the motor and the like when the brake booster BB is abnormal will be described with reference to the time chart of FIG.
When the brake booster BB is abnormal, as shown in FIGS. 7A and 7B, when the driver depresses the brake pedal BP (time t1), the required caliper pressure immediately rises. The estimated caliper pressure filter value after filtering rises with a delay (time t2).

  As a result, the deviation between the required caliper pressure and the estimated caliper pressure filter value increases, so that the deviation is larger than the first threshold (between times t1 and t3) or the deviation is less than or equal to the first threshold. Is less than the predetermined time Tth (between times t3 and t4), the boost control is executed (between times t1 and t4). That is, when the boost control is selected at time t1, the motor 9 is driven (ON) with an output value corresponding to the required caliper pressure as shown in FIG. 7C, and as shown in FIG. 7D. A current is supplied to the suction valve 7 and the suction valve 7 is opened. As shown in FIG. 7E, the command current value is output to the pressure regulating valve R, and the pressure difference between the upstream and downstream of the pressure regulating valve R gradually increases. It is adjusted to go.

  Then, as shown in FIG. 7B, when the time during which the deviation is equal to or less than the first threshold is equal to or longer than a predetermined time Tth, the control shifts to holding control (time t4). That is, when the holding control is selected at time t4, as shown in FIGS. 7C to 7E, the motor 9 is turned off, the current supply to the suction valve 7 is shut off, and the suction valve 7 is closed. Then, a constant command current value is output to the pressure regulating valve R, and the differential pressure upstream and downstream of the pressure regulating valve R is held.

  As a result, it is possible to suppress the power consumption in the motor 9 and the suction valve 7 as compared with the mode in which the boost control is continued after time t4, and the heat generation from the motor 9, the motor 9 and the suction valve 7 are driven. Heat generation from the driving circuit (the motor driving unit 26, the suction valve driving unit 27b, etc.) can be suppressed.

  As shown in FIGS. 7A and 7B, during the holding control, when the driver increases the brake pedal BP (time t5) and the deviation becomes larger than the second threshold (time t6), the holding is performed. Switch from control to step-up control. Thereafter, as described above, when the conditions for entering the holding control are met (time t7), the boost control is switched to the holding control.

As described above, according to the present embodiment, the following effects can be obtained in addition to the effects described above.
As a related parameter, the master cylinder pressure that is directly linked to the brake fluid pressure is acquired, so that the pump can be accurately controlled without being affected by play, for example, compared to a mode in which the stroke amount of the brake pedal is acquired as a related parameter. Can do.

In addition, this invention is not limited to the said embodiment, It can utilize with various forms so that it may illustrate below.
In the above embodiment, it is determined whether or not the related parameter is constant for a predetermined time or more by looking at the deviation between the required caliper pressure and the estimated caliper pressure filter value, but the present invention is not limited to this. is not. For example, it may be determined whether the value of the master cylinder pressure itself is constant for a predetermined time or more, or it may be determined whether the stroke amount of the brake pedal is constant for a predetermined time or more.

  In addition, for example, a filter processing unit that calculates a required caliper pressure filter value by executing a filter process that delays a change in the value with respect to the required caliper pressure is provided, and the boosting unit includes the request caliper pressure filter value and the request caliper. When the state in which the amount of deviation from the pressure is equal to or less than a predetermined value continues for a predetermined time, the related parameter may be determined to be constant for a predetermined time or more.

  In the above embodiment, the present invention is applied to the control when the brake booster BB is abnormal. However, the present invention is not limited to this, and the present invention may be applied to, for example, brake assist control.

  In the above-described embodiment, the holding control of the hydraulic pressure of the wheel brake is performed by controlling the suction valve 7 and the pressure regulating valve R. However, the present invention is not limited to this. For example, the inlet valve 1 and the outlet valve 2 are connected to each other. Holding control may be performed by closing.

  In the above-described embodiment, the brake booster BB is exemplified as operating by negative pressure. However, the present invention is not limited to this, and the brake booster BB may be operated by hydraulic pressure or directly operated by an electric motor. .

DESCRIPTION OF SYMBOLS 9 Motor 20 Control part 21 Determination means 22 Required caliper pressure calculation means 23 Estimated caliper pressure calculation means 24 Filter processing means 25 Boosting means 26 Motor drive part 27 Valve drive part 30 Pressure sensor 40 Negative pressure chamber pressure sensor 100 Brake fluid pressure for vehicles Control device CR Vehicle FL, FR, RL, RR Wheel brake MC Master cylinder

Claims (4)

A vehicle brake fluid pressure control device including a pump that pumps brake fluid from a master cylinder and can increase the fluid pressure of a wheel brake so that the fluid pressure is higher than the master cylinder pressure,
Obtaining means for obtaining the master cylinder pressure ;
A pressure increasing means for operating the pump based on the master cylinder pressure to increase the hydraulic pressure of the wheel brake ;
Estimated wheel cylinder pressure calculating means for calculating the wheel brake hydraulic pressure as an estimated wheel cylinder pressure based on a past control history;
Filter processing means for calculating an estimated wheel cylinder pressure filter value by performing a filter process on the estimated wheel cylinder pressure;
Request wheel cylinder pressure calculating means for calculating a request wheel cylinder pressure based on at least the master cylinder pressure,
When the vehicle is traveling , the master cylinder pressure is increased when a deviation amount between the estimated wheel cylinder pressure filter value and the required wheel cylinder pressure remains below a predetermined value for a predetermined time. Is determined to be constant for a predetermined time or more, and the hydraulic pressure of the wheel brake is maintained and the pump is stopped. The estimated wheel cylinder pressure calculating means calculates an estimated wheel cylinder pressure for each wheel brake corresponding to two front wheels,
The boosting means uses, as the estimated wheel cylinder pressure filter value, a value corresponding to the smaller estimated wheel cylinder pressure of the two estimated wheel cylinder pressures calculated by the estimated wheel cylinder pressure calculating means. The brake fluid pressure control device for a vehicle according to claim 1 . A vehicle brake fluid pressure control device including a pump that pumps brake fluid from a master cylinder and can increase the fluid pressure of a wheel brake so that the fluid pressure is higher than the master cylinder pressure,
Obtaining means for obtaining the master cylinder pressure ;
A pressure increasing means for operating the pump based on the master cylinder pressure to increase the hydraulic pressure of the wheel brake ;
Request wheel cylinder pressure calculating means for calculating a request wheel cylinder pressure based on at least the master cylinder pressure;
Filter processing means for calculating a required wheel cylinder pressure filter value by performing a filtering process on the required wheel cylinder pressure,
When the vehicle is running , the master cylinder pressure is increased when a deviation amount between the required wheel cylinder pressure filter value and the required wheel cylinder pressure is less than or equal to a predetermined value during a predetermined time. Is determined to be constant for a predetermined time or more, and the hydraulic pressure of the wheel brake is maintained and the pump is stopped. A determination means for determining whether the booster is normal;
Said boosting means, when the booster is determined not to be normal by the determining means, any one of claims 1 to 3, characterized in that to control the pump based on the master cylinder pressure The vehicle brake fluid pressure control device according to claim 1.

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