JP2008239114A - Control device and control method for brake - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure larger braking force when valve failure occurs in a brake. <P>SOLUTION: In this brake control method, in regard to the brake having a master cylinder 4, a wheel cylinder 14, a shut-off valve 10, a motor M1, an in valve 11 and an out valve 12, abnormalities of the shut-off valve 10 and the valves 11, 12 are detected. Based on the detection result, a control mode determination part 33 determines whether or not transfer to a pressure intensifying control mode, a pressure reducing control mode and a holding control mode of wheel cylinder pressure by the shut-off valve 10 and the valves 11, 12 is possible. By using the control mode determined to be transferable, current carrying amount to each valve is controlled so as to generate wheel cylinder hydraulic pressure corresponding to operation amount of a brake operation means. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a brake control device and a control method applied to a vehicle or the like.

  In order to improve safety, a brake applied to a vehicle or the like has a structure for assisting a driver's brake operation or automatically stabilizing the vehicle behavior.

  For example, a shutoff valve is provided between the master cylinder and the wheel cylinder of the brake pedal, and a pump that increases the hydraulic pressure supplied to the wheel cylinder according to the brake operation while shutting off the shutoff valve at normal times, In order to achieve the target braking force according to the detected brake operation amount and the target braking force necessary to stabilize the vehicle behavior, an electric hydraulic brake that controls the in-valve and the out-valve at the inlet of the wheel cylinder is known. ing.

  In such an electric hydraulic brake, a structure is considered in which braking force is secured by backup means even if a failure occurs. For example, when a failure occurs in the front wheel solenoid valve, the shut-off valve is opened and the in-valve and out-valve are closed so that the driver's pedal effort is transmitted directly to the wheel cylinder via the master cylinder. (Hereinafter, this state is referred to as “mechanical backup control mode”), and it is known that the braking force of the front wheels is ensured even when the valve fails (see, for example, Patent Document 1).

JP-A-2005-41423

  However, when a failure occurs in the solenoid valve on the front wheel, the braking force of the failed wheel is generated based on the wheel cylinder pressure that is pressurized by the driver's pedal effort, so the braking force is greater in the case of failure than in the normal state. descend.

  An object of the present invention is to secure a larger braking force when a brake valve malfunctions.

  When a valve failure is detected, it is determined whether or not it is possible to shift to the pressure increasing control mode, the holding control mode, and the pressure reducing control mode, and the brake is controlled according to the determination result.

  More braking force can be ensured when the brake valve fails.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a hydraulic circuit diagram of a brake device according to an embodiment of the present invention.

  The brake device has a master cylinder 4 that supplies brake oil in response to a depression operation of the brake pedal 1 by the driver. The master cylinder 4 has a first master cylinder chamber 4R and a second master cylinder chamber 4L, and liquid paths 7R and 7L are connected to these master cylinder chambers, respectively. The other end of each of the liquid passages 7R and 7L has a braking force of an FR wheel and an FL wheel (where the right front wheel is called FR wheel, the left front wheel is called FL wheel, the right rear wheel is called RR wheel, and the left rear wheel is called RL wheel). The wheel cylinders 14FR and 14FL for controlling are connected. In the wheel cylinder, the braking force changes according to the hydraulic pressure.

  Between the liquid passages 7R and 7L between the master cylinder 4 and the wheel cylinders 14FR and 14FL, normally open type (off when not excited) shut-off valves 10R and 10L are provided, respectively. The shut-off valves 10R and 10L control communication between the master cylinder 4, the FR wheel and the FL wheel wheel cylinders 14FR and 14FL.

  A stroke simulator 5 is connected to a liquid path 7R between the master cylinder 4 and the shutoff valve 10R via a switching valve 6. The stroke simulator 5 has a function of securing the stroke of the brake pedal 1 by absorbing the brake oil and generating the driver's pedal feeling. When the shut-off valves 10R and 10L are closed, the switching valve 6 is opened, the stroke simulator 5 is operated, and the stroke of the brake pedal 1 is secured. When either of the shut-off valves 10R and 10L is open, the switching valve 6 is closed to the stroke simulator 5 so that brake oil can be supplied from the master cylinder 4 to the wheel cylinder 14FR or 14FL. Prevent the supply of brake oil.

A reservoir 3 for storing brake oil is connected to the master cylinder 4, and one end of a liquid path 18 is connected to the reservoir 3. In the liquid path 18, two oil pumps P1, P2 driven by motors M1, M2 are provided in parallel. In addition, a liquid path 18 between the reservoir 3 and each oil pump P1, P2 has one end of a liquid path 17 for discharging brake oil from each wheel cylinder 14FR, 14FL, 14RR, 14RL (hereinafter referred to as 14FR to 14RL). Is connected. A relief valve 16 is provided between the liquid passage 17 and the liquid passage 15 on the discharge side of each oil pump P1, P2, so that excessive hydraulic pressure is not applied, and the discharge pressure of the pumps P1, P2 is equal to or higher than a predetermined value. In this case, the valve is opened and the liquid passage 15 and the liquid passage 17 are communicated.

  The discharge sides of the pumps P1 and P2 are connected to the wheel cylinders 14FR to 14RL of the FR to RL wheels via the liquid passage 15, respectively. Brake oil is supplied to each of the wheel cylinders 14FR to 14RL by driving the pumps P1 and P2 according to the operation of the brake pedal. In order to control the inflow amount of brake oil supplied from the pumps P1 and P2 to the respective wheel cylinders, a normally closed type is provided between the liquid passage 15 on the discharge side of the pumps P1 and P2 and the respective wheel cylinders 14FR to 14RL. Linear in valves 11FR to 11RL are provided. Further, in order to control the amount of brake oil flowing from the wheel cylinder to the reservoir, normally closed linear out valves 12FR, 12FL and rear wheel are respectively provided between the front wheel wheel cylinders 14FR, 14FL and the liquid passage 17. Between the wheel cylinders 14RR and 14RL and the liquid passage 17, normally open linear out valves 12RR and 12RL are provided, respectively. The linear in valves 11FR to 11RL each function as a pressure increasing (holding) valve for the wheel cylinder of each wheel. On the other hand, the linear out valves 12FR to 12RL function as pressure reducing valves for the wheel cylinders 14FR to 14RL of the respective wheels. The wheel cylinder pressure is controlled independently by these linear valves.

  When no drive current is supplied to each valve, the shut-off valves 10R and 10L are opened, the in valves 11FR to 11RL are closed, and the normally closed linear out valves 12FR and 12FL are closed. The open linear out valves 12RR and 12RL are maintained in the open state. In this state, since the master cylinder 4 communicates with the front wheel cylinders 14FR and 14FL, the pressure of the master cylinder 4 directly acts on the right and left front wheel cylinders 14FR and 14FL. Therefore, even when a failure occurs, the pressure of the master cylinder 4 pressurized by the driver's pedal effort by stopping the power supply to each valve acts on the wheel cylinders of the left and right front wheels, and the braking force is increased. It can be secured. Moreover, since the out valve is opened on the rear wheel, unnecessary braking force is not generated.

  The brake pedal is provided with a stroke sensor 2 in order to detect the depression amount of the pedal. Master cylinder pressure sensors 8R and 8L are provided in the fluid passages 7R and 7L connected to the master cylinder 4 in order to detect the fluid pressure of the master cylinder 4, respectively. A discharge pressure sensor 9 for detecting the discharge hydraulic pressure of the oil pumps P1 and P2 is installed in the liquid path 15 between the discharge side of the oil pumps P1 and P2 and the in valves 11FR to 11RL. Each of the wheel cylinders 14FR to 14RL is provided with a wheel cylinder pressure sensor 13FR to 13RL, respectively, for detecting the wheel cylinder hydraulic pressure.

  FIG. 2 is a system configuration diagram of a control device that controls the hydraulic circuit of FIG. A microcomputer, various sensors, actuators and their drive circuits are described. The motors M1 and M2, the switching valve 6, the shut-off valves 10R and 10L, the linear in valves 11FR to 11RL, and the linear out valves 12FR to 12RL are controlled by the microcomputer 21 and the drive circuit 22. The microcomputer 21 includes, for example, a CPU, ROM, RAM, and input / output device (not shown), and operates according to a program stored in the ROM.

  As shown in FIG. 2, the microcomputer 21 includes a signal indicating the pressure of the master cylinder from the pressure sensors 8R and 8L, a signal indicating the depression amount of the brake pedal from the stroke sensor 2, and a discharge pressure of the oil pump from the discharge pressure sensor 9. , A signal indicating the pressure in each wheel cylinder from the wheel cylinder pressure sensors 13FR to 13RL, and current sensors M1 ', M2', 6 ', 10R', 10L 'installed in the drive circuits of the valves and motors , 11FR ′ to 11RL ′, 12FR ′ to 12RL ′, signals representing the currents flowing to the drive circuits of the valves are input.

  FIG. 3 shows a functional block diagram of the control device of FIG.

  By performing the processing described later by this control system, the motor and each valve can be driven according to various sensor information, the hydraulic pressure in each wheel cylinder can be controlled, and a braking force can be generated on each wheel. it can. Further, the microcomputer 21 can control the hydraulic pressure of each wheel cylinder with the remaining electromagnetic valves when a failure occurs in the linear in valves 11FR to 11RL and the linear out valves 12FR to 12RL installed in each wheel cylinder. A control mode determination unit that determines whether or not to switch the control mode (pressure increase control, holding control, pressure reduction control, mechanical backup control). Details of the control mode determination unit will be described later with reference to FIGS. If this control mode determination unit determines that control is possible even when each valve fails, the pressure-increasing control mode, the holding control mode, and the pressure-reducing control mode for the failed wheel can be continued. Can be suppressed.

  The wheel braking force is also controlled by a vehicle behavior control device comprising a microcomputer 28. The microcomputer 28 has the same configuration as the microcomputer 21 described above, and communicates necessary information with the microcomputer 21 via a communication line such as CAN. As shown in FIG. 2, the microcomputer 28 has a signal indicating the speed of each wheel from the wheel speed sensor 23 installed on each wheel, information on the yaw rate of the vehicle detected by the yaw rate sensor 24, and a handle. A signal indicating the steering angle detected by the steering angle sensor 25, a signal indicating the longitudinal acceleration of the vehicle from the longitudinal acceleration sensor 26, and a signal indicating the lateral acceleration of the vehicle detected from the lateral acceleration sensor 27. Entered.

  The microcomputer 28 detects the vehicle spin, drift-out, and wheel lock based on information on the steering angle, yaw rate, lateral acceleration, and wheel speed of each wheel detected by the sensor, and suppresses them. Includes a vehicle motion control block for calculating a target braking force of the corresponding wheel. The calculated target braking force is sent to the microcomputer 21 through the communication line. The microcomputer 21 controls the motor and each valve based on the target braking force, generates a braking force on each wheel, and stabilizes the vehicle behavior.

Next, a control block diagram stored in the microcomputer 21 will be described with reference to FIG. First, the master pressure sensor 8R, and the master cylinder pressure detected by 8L, based on the pedal depression amount detected by the stroke sensor 2, the target braking force calculating section 30, (1) the target braking force G _t of the entire vehicle by formula Calculated.

G _t = K _{m / c} P _{m / c} + K _st L _st (1) where K _{m / c} , P _{m / c} , K _st , and L _st are the master cylinder pressure gain, master cylinder pressure, and pedal, respectively. Denotes the amount of pedal depression and pedal depression. Next, in the braking force distribution calculation unit, the target braking force of each wheel is calculated based on the target braking force G _{t of the} entire vehicle and the target braking force of each wheel for vehicle stabilization calculated by the microcomputer 28. To do. Further, the target hydraulic pressure calculation unit converts each wheel target braking force into the target hydraulic pressure of each wheel. A control mode determination unit 33 (described in detail with reference to FIGS. 5 to 7 and 9) determines whether or not the hydraulic pressure control of each wheel cylinder is possible, and includes a pressure increase control mode, a holding control mode, a pressure reduction control mode, Determine the mechanical backup control mode. Based on the control mode determined by the control mode determination unit 33, the target hydraulic pressure of each wheel, and the actual hydraulic pressure of each wheel, the valve control unit 34 of each wheel controls the in-valve, the out-valve, and the shut-off valve. The wheel cylinder hydraulic pressure is controlled. Further, the motor control unit drives the motor to generate the hydraulic pressure when the hydraulic pressure is required for the wheel cylinder based on the target hydraulic pressure of each wheel. Although only the motor M1 is shown in FIG. 3, only the motor M2 may be driven or both the motors M1 and M2 may be driven.

  FIG. 4 is a detailed explanatory diagram of the valve control unit and the abnormality detection unit of the FR wheel in FIG. Based on the deviation between the target current of each valve and the current value detected by the current sensor, the abnormality detection unit 34 determines that the valve is abnormal when the current deviation continues for a predetermined time at a predetermined value or more. Is transmitted to the control mode determination unit. Although not shown in the figure, other sensors such as a voltage sensor may be used to detect abnormalities such as disconnection, short circuit, ground fault, etc. of the valve power supply and drive circuit.

  Based on the abnormality flag output from the abnormality detection unit 34, the target hydraulic pressure and the actual hydraulic pressure of the wheel cylinder, the control mode determination unit 33 performs a pressure increase control mode, a pressure reduction control mode, a holding control mode, and a mechanical backup control for each wheel. Select a mode. Here, the control method of the valve in the control mode will be described in detail by taking the FR wheel as an example. In the pressure increase control mode, the switching valve 6 of the stroke simulator 5 is opened, the shut-off valve 10R is closed, and the out valve 12FR is closed. In this state, the motors M1 and M2 are controlled to generate hydraulic pressure by the pumps P1 and P2, the in-valve 11FR is controlled based on the deviation between the target hydraulic pressure and the actual hydraulic pressure, and the wheel cylinder 14FR is set to a desired hydraulic pressure. Increase pressure.

  In the holding control mode, the pumps P1 and P2 are stopped, the switching valve 6 of the stroke simulator 5 is opened, and the shut-off valve 10R, the in-valve 11FR, and the out-valve 12FR are closed. As a result, the wheel cylinder 14FR is disconnected from the master cylinder 4 and the reservoir 3, and the hydraulic pressure is maintained.

In the pressure reduction control mode, the pumps P1 and P2 are stopped, the switching valve 6 of the stroke simulator 5 is opened, the in-valve 11FR and the shut-off valve 10R are closed, and the out valve 12FR is set to the target hydraulic pressure and the actual hydraulic pressure. To control the wheel cylinder 14FR to a desired hydraulic pressure.

  In the mechanical backup mode, the normally open shut-off valve 10R is automatically opened by de-energizing each valve, and the switching valve 6, in-valve 11FR and out-valve 12FR of the normally-closed stroke simulator are Close the valve. As a result, the master cylinder 4 and the wheel cylinder 14FR are communicated with each other, the wheel cylinder 14FR and the reservoir 3 are disconnected, and the driver's pedaling force directly acts on the wheel cylinder 14FR. In the mechanical backup mode of the RR wheel, the normally closed in-valve 11RR is closed and the normally open out valve 12RR is opened, and the wheel cylinder 14RR and the reservoir 3 are communicated with each other so that unnecessary hydraulic pressure is generated. It does not hang.

  The control mode described above is determined by the control mode determination unit 33. The in-valve control unit 40, the out-valve control unit 41, and the shut-off valve control unit 42 calculate the target current based on the control mode, the target hydraulic pressure, and the actual hydraulic pressure. The current control units 44 to 46 of the valves control the drive circuit based on the difference between the target current and the actual current to drive the in-valve 11FR, the out-valve 12FR, and the shut-off valve 10R. Although not shown in the figure, the switching valve of the stroke simulator is also controlled based on each control mode. 3 and 4, the motor and each valve are driven to control the wheel cylinder hydraulic pressure of each wheel.

  Next, the control mode determination unit 33 described in FIGS. 5 to 7 and 9 will be described in detail. The control mode determination unit determines a control mode for each wheel based on the state of the valve, the target hydraulic pressure of the wheel cylinder, and the actual hydraulic pressure. FIG. 5 shows a control flowchart of the control mode determination unit of FIG. The control mode determination unit 33 shown in FIG. 5 determines a control mode determination unit (FIGS. 6, 7, and 9) according to the valve failure part based on the abnormality flag of each valve output from the abnormality detection unit. It is a flowchart for doing. The above flowchart assumes a front wheel with a shut-off valve, but can also be applied to a rear wheel by omitting S700 and S800.

  First, in S100, it is determined whether or not there is a failure in the valve. If there is no failure in the valve (No determination in S100), the process proceeds to a control mode determination unit (FIG. 6) when the valve is normal in S200 described later. If there is a failure in the valve (Yes in S100), the process proceeds to a determination of whether there is a failure in the in-valve in S300. When there is a failure in the in-valve (Yes in S300), the process proceeds to a control mode determination unit (FIG. 7) at the time of in-valve failure in S400. If there is no failure in the in-valve (No in S300), the process proceeds to S500 to determine whether or not there is a failure in the out-valve. If there is a failure in the out valve (Yes in S500), the process proceeds to the control mode determination unit (FIG. 9) at the time of out valve failure. If there is no failure in the out valve (No determination in S500), the process proceeds to the determination of whether there is a failure in the shut-off valve in S700. If the shut-off valve has a failure (Yes in S700), the mechanical backup mode is selected as the control mode. If the shut-off valve has no failure (No in S700), the process is terminated. By repeating this process, it is possible to proceed to the control mode determination unit corresponding to the failed part of the valve.

FIG. 6 shows a control flowchart when the valve is normal in the control mode determination unit of FIG. Target fluid step S210 pressure P * w _{/ c} and the actual hydraulic absolute value of the deviation of the pressure P _{w / c} | ΔP | is determined whether more than a predetermined value K. If the value is equal to or smaller than the predetermined value K (No in S210), it is determined that the desired hydraulic pressure can be controlled, and the holding control mode is selected in S250. If it is equal to or greater than the predetermined value K (Yes in S210), it is determined that the desired hydraulic pressure cannot be controlled, and the process proceeds to S220. The predetermined value K is a threshold value for determining whether or not the desired hydraulic pressure can be controlled. By providing the determination in S210, frequent switching between the pressure increase control and the pressure reduction control can be suppressed. In other figures, K is used, but it is necessary to set appropriately for each valve. In S220, it is determined whether ΔP is positive, that is, whether pressure increase control is necessary. When ΔP is positive (Yes in S220), the pressure increase control mode is selected in S230. If ΔP is not positive (S220 is No), the decompression control mode is selected in S240.

FIG. 7 is a control flowchart when the in-valve failure occurs in the control mode determination unit of FIG. First, in S410, it is determined whether the in-valve is a normally open type. If the in-valve is normally open (Yes in S410), the process proceeds to S415. If the in-valve is not normally open (No in S410), the process proceeds to S430. In S415, it is determined whether or not the wheel cylinder can be arbitrarily pressurized. If the pressure can be increased, the backup control mode is selected in S420. If the pressure cannot be increased, the backup control mode is selected in S460. The fact that the wheel cylinder can be increased arbitrarily means whether or not the wheel cylinder can be increased to an arbitrary target hydraulic pressure. For example, when the hydraulic pressure source is an accumulator and the pressure between the in-valve and the accumulator is always maintained at a high pressure, the wheel cylinder pressure cannot be controlled when the in-valve is opened. Therefore, it is determined that the wheel cylinder cannot be increased arbitrarily. Also, if the hydraulic pressure source is an oil pump and no check valve is installed between the in-valve and the hydraulic pressure source, the hydraulic pressure may escape from the open in-valve side even if the wheel cylinder is pressurized. It is determined that the cylinder cannot be controlled arbitrarily. Conversely, if a check valve is installed between the oil pump and the in-valve and the wheel cylinder pressure does not flow back to the in-valve side, the oil pump can increase the wheel cylinder to the target hydraulic pressure even when the in-valve is open. Therefore, it is determined that the wheel cylinder can be arbitrarily pressurized.

In S420, the absolute value of the deviation of the target hydraulic pressure P * w _{/ c} and the actual hydraulic pressure P _{w / c} | ΔP | is determined whether more than a predetermined value K. If the value is equal to or less than the predetermined value K (No in S420), it is determined that the desired hydraulic pressure is being controlled, and the holding control mode is selected in S455. If it is equal to or greater than the predetermined value K (Yes in S420), it is determined that the wheel cylinder hydraulic pressure cannot be controlled to a desired hydraulic pressure, and the process proceeds to S425. In S425, it is determined whether or not ΔP is positive. If ΔP is positive (Yes in S425), the pressure increase control mode is set in S445. If ΔP is not positive (No in S425), the decompression control mode is selected in S450. Next, a case where the in-valve is not a normally open type (S415 is No determination) will be described. In S430, it is determined whether or not the master cylinder pressure Pm _{/ c} is smaller than the wheel cylinder pressure _{Pw / c} . If the master cylinder pressure P _{m / c} is not smaller than the wheel cylinder pressure P _{w / c} (S430: No), the mechanical cylinder backup mode is established in S460 so that the wheel cylinder and the master cylinder communicate with each other. Increase to master cylinder pressure. When the master cylinder pressure P _{m / c} is smaller than the wheel cylinder pressure P _{w / c} , the process proceeds to S435, and it is determined whether or not the absolute value | ΔP | of the hydraulic pressure deviation is equal to or greater than a predetermined value K. If the value is equal to or less than the predetermined value K (S435: No), the holding control mode is set in S455. If the value is equal to or less than the predetermined value K (Yes in S435), it is determined whether or not ΔP is positive in S440. If ΔP is positive (Yes in S440), the in-valve is closed and increased. Since pressure control cannot be performed, the holding control mode is set in S455. When ΔP is not positive (No in S440), the decompression control mode is selected.

  FIG. 8 shows a time chart of the hydraulic pressure when a failure occurs in the front wheel in-valve in the present embodiment. This illustrates the effect of the control mode determination unit when the in-valve fails, taking as an example the change in hydraulic pressure when a failure occurs in the front wheel in-valve shown in FIG. When a failure occurs in the normally closed front wheel in-valve, the conventional known technique drops the failed valve wheel to the mechanical backup mode. Therefore, only the brake corresponding to the driver's pedal effort can be applied to the front wheel where the failure has occurred. On the other hand, in the present embodiment, the control mode determination unit at the time of in-valve failure determines whether or not the hydraulic pressure control is possible with a normal valve and selects the control mode. Therefore, an unnecessary hydraulic pressure as shown in FIG. Decline can be prevented.

A specific processing flow will be described with reference to FIGS. First, the abnormality detection unit in FIG. 4 detects the occurrence of a valve failure and sets an in-valve abnormality flag. Based on the abnormality flag, the control mode determination unit S100 illustrated in FIG. 5 determines that there is an abnormality in the valve and proceeds to S300. In S300, since the in-valve is abnormal, a Yes determination is made, and the process proceeds to the control mode determination unit at the time of in-valve failure in S400. In S410 of FIG. 7, since the in-valve is normally closed, the process proceeds to S430,
Since the master cylinder pressure P _{m / c} at S430 is smaller than the wheel cylinder pressure P _{w / c,} Yes determination, the process proceeds to S435. In S435, it is determined that | ΔP | is equal to or greater than the predetermined value K, and the process proceeds to S440. In the range A, Yes determination is made when ΔP> 0, and the holding control mode is selected in S455. In the range of B, ΔP <0 and the pressure reduction control mode is set in S450. In the range of C, the master cylinder pressure P _{m / c} ≧ the wheel cylinder pressure P _{w / c is} satisfied in S430, and the mechanical backup mode is selected in S460. As can be seen from the above, in the known technology, the wheel in which the in-valve failure occurred was dropped into the mechanical back mode and the braking force of the wheel was reduced, but in this embodiment, is it possible to control the hydraulic pressure of the wheel cylinder? When the control is possible, the holding control mode and the pressure-reducing control mode are selected. Therefore, an unnecessary decrease in braking force can be suppressed.

FIG. 9 shows a control flowchart in the case of out valve failure in the control mode determination unit of FIG. First, in S610, it is determined whether or not the out valve is a normally closed type. If the out valve is not normally closed (No in S610), the hydraulic pressure of the wheel cylinder will escape from the out valve to the reservoir when the control of the out valve is stopped, so the mechanical backup control mode is selected in S680. If the out valve is a normally closed type (Yes in S610), it is determined in S620 whether decompression control is possible from the out valve of the other wheel. FIG. 10 shows an example of the case where pressure reduction control is possible from the out valve of the other wheel. Even when the out valve of the normally closed FR wheel fails as shown in FIG. 10, the pressure reduction control can be performed from the out valve 12FL via the in valve 11FR, the liquid passage 17, and the in valve 11FL of another wheel. The control mode at this time is referred to as a pressure reduction control mode at the time of out valve failure. In the decompression control mode at the time of out valve failure, the pumps P1 and P2 are stopped, the switching valve of the stroke simulator is opened, and the shutoff valve is closed. In addition, the in-valve of the wheel that releases the hydraulic pressure of the failed wheel and the failed wheel is opened, the other in-valve is closed, and the out valve of the wheel that releases the hydraulic pressure of the failed wheel is the deviation between the target hydraulic pressure and the actual hydraulic pressure. And control to reduce the pressure to a desired hydraulic pressure. Note that the target hydraulic pressure and the actual hydraulic pressure when controlling the out valve may be a failed wheel or a wheel that removes the hydraulic pressure of the failed wheel. Further, the number of out valves for releasing the hydraulic pressure of the failed wheel is not limited to one, and pressure reduction control may be performed using a plurality of out valves. In S620, when pressure reduction control is not possible from the out valve of the other wheel (No determination in S620), the mechanical backup control mode is set in S680. If decompression control is possible from the out-valve of the other wheel (Yes in S620), the process proceeds to S630. In S630, it is determined whether or not the absolute value | ΔP | of the hydraulic pressure deviation is equal to or greater than a predetermined value K. If the value is equal to or smaller than the predetermined value K (No in S630), the holding control mode is set in S650. If it is equal to or greater than the predetermined value K (Yes in S630), it is determined in S640 whether ΔP is positive, that is, whether pressure increase control is required. If ΔP is positive (Yes in S640). ) Selects the pressure increase control mode of S660. When ΔP is not positive (S640 is No), the pressure reduction control mode at the time of out valve failure is selected.

  FIG. 11 shows a time chart of hydraulic pressure when a failure occurs in the front wheel out valve in the present embodiment. When a failure occurs, in the prior art, the failed wheel of the out valve is dropped to the mechanical backup mode. Therefore, only the brake corresponding to the driver's pedaling force could be applied to the front wheel where the failure occurred. On the other hand, in this embodiment, the control mode determination unit at the time of out valve failure determines whether or not the hydraulic pressure control is possible with a valve that is not broken, and the pressure increase control mode, the holding control mode, and the pressure reduction control mode are set. Since it selects, the fall of an unnecessary hydraulic pressure can be suppressed.

A specific processing flow will be described with reference to FIGS. 4, 5, and 8. First, when a failure occurs in the out valve, the abnormality detection unit 34 in FIG. 4 detects the abnormality and sets an out valve abnormality flag. In response to this, the control mode determination unit 33 selects a control mode determination unit corresponding to the failed part of the valve. First, in S100, there is a valve abnormality, so a Yes determination is made. In S300, the in valve is normal, so a No determination is made. In S500, an out valve is abnormal, a Yes determination is made. In S600, a control mode determination unit at the time of out valve failure (FIG. 9). ) In S610 of FIG. 9, since the out valve is a normally closed type, the process proceeds to Yes. In S620, since pressure reduction control can be performed from the out valve of a wheel other than the failed wheel, the process proceeds to S630 with a Yes determination. In S630, since | ΔP |> K in the range A, the process proceeds to S640, and since ΔP> 0, the pressure increase control mode is selected. In the range of B, the determination in S630 is No, and the holding control mode in S650 is set. In the range of C, since the determination in S630 is Yes and the determination in S640 is ΔP <0, the decompression control mode at the time of out valve failure is selected in S670. As can be seen from the above, conventionally, in the case where an out valve failure has occurred, in order to drop the failed wheel to the mechanical back mode, the braking force of the wheel has been reduced. Since it is determined whether or not the hydraulic pressure control is possible using a valve that is not broken, it is possible to continue the pressure increase control, the holding control, and the pressure reduction control without unnecessarily dropping the failed wheel to the mechanical backup control. Thereby, the fall of braking force can be suppressed.

  FIG. 12 shows whether or not control can be continued for each valve failure site when the control mode determination unit (FIGS. 5 to 7 and 9) is applied to the hydraulic model of FIG. As can be seen from the above, it is possible to suppress unnecessary braking force reduction by selecting whether or not control can be continued with a valve that has not failed, and selecting a control mode for all valve failures that had previously been reduced to mechanical backup. can do.

  According to the embodiment of the present invention, it is possible to suppress a decrease in the braking force of the failed wheel when an electromagnetic valve failure has been a problem in the prior art. Specifically, even when a normally open type in-valve failure, which has been conventionally reduced to the mechanical backup mode, is possible to increase the pressure of the wheel cylinder arbitrarily, this embodiment is applied to increase the normal pressure. The pressure control mode, the holding control mode, and the pressure reduction control mode can be continued. In addition, the holding control mode and the pressure-reducing control mode can be continued even when a normally closed in-valve that has conventionally been switched to the mechanical backup mode has failed. Also, even if the out valve has failed in the mechanical backup mode in the past, if the out valve is normally closed and pressure reduction control can be performed from an out valve other than the faulty wheel, the pressure increase control mode and hold control are the same as during normal operation. Mode and decompression control mode can be continued.

  FIG. 13 is a hydraulic circuit diagram of a brake device according to another embodiment of the present invention. Matters not particularly shown below are the same as those in the first embodiment, and a description thereof will be omitted.

  The brake control device has a master cylinder 4 that supplies brake oil in response to a depression operation of the brake pedal 1 by the driver. The master cylinder 4 has a first master cylinder chamber 4R and a second master cylinder chamber 4L, and liquid paths 7R and 7L are connected to these master cylinder chambers, respectively. Wheel cylinders 14FR and 14FL for controlling the braking force of the FR wheel and the FL wheel are connected to the other ends of the liquid passages 7R and 7L, respectively.

  Normally open shut-off valves 10R and 10L are provided between the liquid passages 7R and 7L between the master cylinder 3 and the wheel cylinder, respectively. The shut-off valves 10R and 10L control communication and disconnection between the master cylinder 4, the FR wheel and the FL wheel wheel cylinders 14FR and 14FL.

  A stroke simulator 5 is connected to a liquid path 7R between the master cylinder 4 and the shutoff valve 10R via a switching valve 6. The stroke simulator 5 has a function of securing the stroke of the brake pedal 1 by absorbing the brake oil and generating the driver's pedal feeling. When the shut-off valves 10R and 10L are closed, the switching valve 6 is opened, the stroke simulator 5 is operated, and the stroke of the brake pedal 1 is secured. Further, when either of the shut-off valves 10R, 10L is open, brake oil is supplied to the wheel cylinder 14FR or 14FL. Therefore, the switching valve 6 is closed to prevent the brake oil from being supplied to the stroke simulator 5.

  A reservoir 3 for storing brake oil is connected to the master cylinder 4, and one end of a liquid path 18 is connected to the reservoir 3. The liquid path 18 is provided with an oil pump P1 driven by a motor M1. Further, one end of a liquid path 17 for discharging brake oil from each of the wheel cylinders 14FR to 14RL is connected to the liquid path 18 between the reservoir 3 and each oil pump P1. High pressure hydraulic pressure is accumulated in the fluid passage 15 between the discharge side of the oil pump P1 and each of the wheel cylinders 14FR to 14RL via a normally open switching valve 20 that cuts off the supply of brake oil from the accumulator to the wheel cylinder. An accumulator 19 is connected. In addition, a relief valve 16 is provided between the liquid passage 15 and the liquid passage 17, and is opened when the accumulator pressure becomes a predetermined value or more, and the liquid pressure is returned to the reservoir 3. Yes.

Normally closed linear in-valves 11FR to 11RL are provided between the liquid passage 15 and the wheel cylinders 14FR to 14RL, respectively. Also, normally closed linear out valves 12FR and 12FL are provided between the front wheel cylinders 14FR and 14FL and the liquid passage 17, respectively, and between the rear wheel foil cylinders 14RR and 14RL and the liquid passage 17 are normally opened. Type linear out valves 12RR, 12RL are provided. Each linear valve 11FR ~
Each of 11RL functions as a pressure increasing (holding) valve for the wheel cylinder of each wheel. On the other hand, the linear out valves 12FR to 12RL function as decompression control valves for the wheel cylinders 14FR to 14RL of the respective wheels. The wheel cylinder pressure is controlled independently by these linear valves.

When no drive current is supplied to each valve, the shut-off valves 10R and 10L are kept open, the in valves 11RL to 11RL are closed, and the normally closed linear out valves 12FR and 12FL are closed. The normally open linear out valves 12RR and 12RL are maintained in the open state. As a result, the master cylinder 4 communicates directly with the front wheel wheel cylinders 14FR, 14FL, so that the left and right front wheel wheel cylinders 14FR, 14FL can be controlled by the master cylinder 4. With the above configuration, even when a failure occurs, the left and right front wheels can ensure a braking force equivalent to the pedaling force by the master cylinder 4 pressurized by the driver's pedaling force by stopping the power supply.

  In the brake pedal, a stroke sensor 2 is installed on the brake pedal 1 in order to detect the depression amount of the pedal. Master cylinder pressure sensors 8R and 8L are provided in the fluid passages 7R and 7L connected to the master cylinder 4 in order to detect the fluid pressure of the master cylinder 4, respectively. Further, a discharge pressure sensor 9 for detecting the discharge hydraulic pressure of the oil pumps P1 and P2 is installed in the liquid path 15 between the discharge side of the oil pumps P1 and P2 and the in valves 11RL to 11RL. Each of the wheel cylinders 14FR to 14RL is provided with a wheel cylinder pressure sensor 13FR to 13RL in order to detect the wheel cylinder hydraulic pressure. The system configuration diagram of this embodiment is substantially the same as the system configuration diagram (FIG. 2) of the first embodiment. The difference is that in Example 1, there are two sets of motors and pumps and their drive circuits, whereas in Example 2, there is only one set, and in Example 2, switching between the accumulator and each wheel cylinder is different. A valve and its drive circuit are added.

  The control block diagram of the second embodiment has the same configuration as the control block diagram of the first embodiment (FIGS. 3 and 4). However, the drive timing of the motor is different. In the configuration of the first embodiment, the drive timing of the motor is at the time of pressure increase control, whereas in the configuration of the second embodiment, the oil pump plays a role of supplying hydraulic pressure to the accumulator. Drive when drops.

  When a failure occurs in the in-valve 11FR of FIG. 13 and the control mode determination unit described in FIGS. 5 to 7 and FIG. 9 is applied, the change in hydraulic pressure is as shown in FIG. The specific processing flow is the same as in the first embodiment.

  When a failure occurs in the out valve 12FR in FIG. 13 and the control mode determination unit described in FIGS. 5 to 7 and FIG. 9 is applied, the change in hydraulic pressure is as shown in FIG. 11 as in the first embodiment. . The specific processing flow is the same as in the first embodiment. However, in the decompression control mode at the time of out valve failure, the desired decompression control is performed from the out valve other than the malfunctioning wheel by closing the switching valve 20 between the accumulator and each wheel cylinder in order to decompress from the out valve of the other wheel. .

  When the control mode determination unit shown in FIGS. 5 to 7 and 9 is applied to the hydraulic model shown in FIG. 13, whether or not to continue the control for each valve failure part is the same as that shown in FIG. is there. As can be seen, it is possible to reduce unnecessary braking force by judging whether or not control can be continued with a valve that has not failed, and selecting a control mode for all valve failures that were previously reduced to mechanical backup. Can be suppressed.

  As a third embodiment, an example in which the control mode determination unit described in FIGS. 5 to 7 and 9 is applied to a brake-by-wire in which two front wheels are an electric hydraulic brake and two rear wheels are an electric brake will be described. Matters not particularly shown below are the same as those in the first embodiment, and a description thereof will be omitted.

  FIG. 14 illustrates a control mode determination unit described in FIGS. 5 to 7 and 9 in a brake-by-wire configuration in which two front wheels are an electric hydraulic brake and two rear wheels are an electric brake. An example where is applied. The brake device has a master cylinder 4 that supplies brake oil in response to a depression operation of the brake pedal 1 by the driver. The master cylinder 4 has a first master cylinder chamber 4R and a second master cylinder chamber 4L, and liquid paths 7R and 7L are connected to these master cylinder chambers, respectively. Wheel cylinders 14FR and 14FL for controlling the braking force of the FR wheel and the FL wheel are connected to the other ends of the liquid passages 7R and 7L, respectively.

  Normally open shut-off valves 10R and 10L are provided between the liquid passages 7R and 7L between the master cylinder 3 and the wheel cylinder, respectively. The shut-off valves 10R and 10L control communication and disconnection between the master cylinder 4, the FR wheel and the FL wheel wheel cylinders 14FR and 14FL.

  A stroke simulator 5 is connected to a liquid path 7R between the master cylinder 4 and the shutoff valve 10R via a switching valve 6. The stroke simulator 5 has a function of securing the stroke of the brake pedal 1 by absorbing the brake oil and generating the driver's pedal feeling. When the shut-off valves 10R and 10L are closed, the switching valve 6 is opened, the stroke simulator 5 is operated, and the stroke of the brake pedal 1 is secured. Further, when either of the shut-off valves 10R, 10L is open, brake oil is supplied to the wheel cylinder 14FR or 14FL. Therefore, the switching valve 6 is closed to prevent the brake oil from being supplied to the stroke simulator 5.

  A reservoir 3 for storing brake oil is connected to the master cylinder 4, and one end of a liquid path 18 is connected to the reservoir 3. In the liquid path 18, two oil pumps P1, P2 driven by motors M1, M2 are provided in parallel. In addition, one end of a fluid passage 17 for discharging brake oil from each of the wheel cylinders 14FR to 14RL is connected to the fluid passage 18 between the reservoir 3 and each of the oil pumps P1 and P2. A relief valve 16 is provided between the liquid passage 17 and the liquid passage 15 on the discharge side of each oil pump P1, P2, so that excessive hydraulic pressure is not applied, and the discharge pressure of the pumps P1, P2 is equal to or higher than a predetermined value. In this case, the valve is opened and the liquid passage 15 and the liquid passage 17 are communicated.

  The discharge sides of the pumps P1 and P2 are connected to wheel cylinders 14FR and 14FL of FR and FL wheels through a liquid passage 15, respectively. Between the fluid passage 15 and the respective wheel cylinders 14FR, 14FL, check valves 50R, 50L permitting only the flow from the pump to the wheel cylinder and normally open linear in valves 11FR, 11FL are provided. Further, normally closed linear out valves 12FR and 12FL are provided between the wheel cylinders 14FR and 14FL and the liquid passage 17, respectively. Each linear in-valve 11FR, 11FL functions when differentially controlling the wheel cylinder pressure of each wheel. On the other hand, the linear out valves 12FR and 12FL function as pressure reducing control valves for the wheel cylinders 14FR and 14FL of the respective wheels. The wheel cylinder pressure is controlled independently by these linear valves.

  During non-control when no drive current is supplied to each valve, the normally open shut-off valves 10R and 10L and the in valves 11FR and 11FL are maintained in the open state, and the normally closed linear out valves 12FR and 12FL are in the closed state. Maintained. Due to the check valve and the closed valve, the pressure of the master cylinder 4 acts on the wheel cylinders 14FR and 14FL of the left and right front wheels. With the above configuration, even when a failure occurs, the left and right front wheels can ensure a braking force equivalent to a pedaling force.

  In the brake pedal, a stroke sensor 2 is installed on the brake pedal 1 in order to detect the depression amount of the pedal. Master cylinder pressure sensors 8R and 8L are provided in the fluid passages 7R and 7L connected to the master cylinder 4 in order to detect the fluid pressure of the master cylinder 4, respectively. Further, a discharge pressure sensor 9 for detecting the discharge hydraulic pressure of the oil pump P1 is installed in the liquid passage 15 between the discharge sides of the oil pumps P1 and P2 and the in valves 11FR and 11FL. The wheel cylinders 14FR and 14FL are provided with wheel cylinder pressure sensors 13FR and 13FL, respectively, for detecting the wheel cylinder hydraulic pressure.

  Although not shown, the two rear wheels have electric brake units attached to the respective wheels, and generate braking force in accordance with a control signal from the brake control unit. Based on information from the master cylinder pressure sensor and stroke sensor, the brake control unit calculates the required braking force for the driver's operation of the brake pedal, and applies the braking force to each rear wheel's electric brake unit to achieve this braking force. Output a control signal. The electric brake unit generates a braking force on each wheel based on the control signal received from the brake control unit.

  The system configuration of the brake device of the third embodiment is the same as the system configuration shown in FIG. 2 except for the following points. In the first embodiment, the rear wheel linear in valve and the linear out valve are used, but in the third embodiment, the electric brake actuator is used. Further, the wheel cylinder pressure sensor installed on the two rear wheels is a thrust sensor for detecting the thrust of the brake actuator in the third embodiment.

  The control block diagram of the two front wheels of the third embodiment has the same configuration as the control block diagram of each valve and motor described in FIGS. 3 and 4 shown in the first embodiment. However, in the pressure increase control mode of the first embodiment, the linear in-valve is driven at the time of pressure increase control and the braking force of each wheel is controlled, whereas in the pressure increase control mode of the third embodiment, the left and right front wheels are controlled. Except when controlling the wheel cylinder pressure to a different pressure, the linear in valve is opened without being driven, the shut-off valve and the linear out valve are closed, and the wheel cylinder pressure of each wheel is controlled. Although control of the electric brakes for the two rear wheels is not shown, the thrust generated by the electric brake actuator is controlled to be the target thrust.

  FIG. 15 is a time chart when the control mode determination unit at the time of in-valve failure is applied to the hydraulic circuit of FIG. This is an example of a change in hydraulic pressure when a failure occurs in the front wheel in-valve. When a failure occurs in a normally open front wheel in-valve, the conventional technology uses the mechanical backup mode to drop the failed valve wheel into the mechanical backup mode and prevent the other normal wheel from being pressurized by the oil pump. It was dropped in. Therefore, when a failure occurs in the valve, only the brake corresponding to the driver's pedaling force can be applied to the two front wheels. On the other hand, in the present embodiment, the control mode determination unit at the time of in-valve failure shown in FIG. 7 determines whether or not hydraulic pressure control is possible with a valve that has not failed, and the pressure increase control mode, the holding control mode, Since the depressurization control mode is selected, an unnecessary decrease in hydraulic pressure can be prevented as shown in FIG.

A specific processing flow will be described with reference to FIGS. First, the abnormality detection unit in FIG. 4 detects the occurrence of a valve failure and sets an in-valve abnormality flag. Based on the abnormality flag, the control mode determination unit S100 illustrated in FIG. 5 is Yes, and the determination is Yes in S300, and the process proceeds to the control mode determination unit at the time of in-valve failure. Next, since the in-valve is normally open, S410 is Yes and the process proceeds to S415. In S415, it is possible to arbitrarily increase the pressure of the wheel cylinder by controlling the oil pump (Yes in S415), and the process proceeds to S420. Target fluid in S420 pressure P * w _{/ c} and the actual hydraulic absolute value of the deviation of the pressure P _{w / c} | ΔP | is determined whether more than a predetermined value K. In the range of A, since it is equal to or greater than the predetermined value K (Yes determination in S420), it is determined that the desired hydraulic pressure cannot be controlled, and the process proceeds to S425. In the range of A, since ΔP is positive (Yes in S425), the pressure increase control mode is selected in S445. In the range of B, since | ΔP | is equal to or smaller than the predetermined value K in S420, the process proceeds to S455, and the holding control mode is selected. In the range of C, since | ΔP | becomes equal to or smaller than the predetermined value K in S420, the process proceeds to S425. In S425,
Since ΔP is negative, the process proceeds to S450 and the pressure reduction control mode is selected. Therefore, when an in-valve failure has occurred, the hydraulic pressure control has been stopped and the mechanical backup control mode has been conventionally reduced. By applying this embodiment, the pressure increasing control mode, the holding control mode, and the pressure reducing control mode are changed. This can be continued, and an unnecessary decrease in hydraulic pressure can be prevented.

  Next, the flow of processing when the out valve of FIG. 14 fails will be described with reference to FIGS. First, the abnormality detection unit in FIG. 4 detects the occurrence of a valve failure and sets an out-valve abnormality flag. Based on the abnormality flag, the control mode determination unit (FIG. 5) becomes Yes in S100, No in S300, Yes in S500, and proceeds to the mode determination unit at the time of out valve failure. In S610, since the out valve is normally closed, the process proceeds to S620. In S620, it is determined whether or not the hydraulic pressure of the failed wheel can be controlled to be reduced from the out valve of the other wheel, but in the configuration of FIG. 14, the reduced pressure control is not possible by the check valves 50R and 50L. Accordingly, the process proceeds to S680 and the mechanical backup mode is selected.

  FIG. 16 shows whether or not control can be continued for each valve failure site when the control mode determination unit shown in FIGS. 5 to 7 and 9 is applied to the hydraulic model shown in FIG. As can be seen from this, it is possible to continue the pressure-increasing control mode, the holding control mode, and the pressure-reducing control mode by applying this embodiment to valve failures that have all been reduced to mechanical backup in the past, which is unnecessary. It can be confirmed that a decrease in braking force can be suppressed.

The hydraulic circuit diagram of the brake device which makes one Embodiment of this invention is shown. The system block diagram of the control apparatus which controls the hydraulic circuit of FIG. 1 is shown. The functional block diagram of the control apparatus of FIG. 2 is shown. The detailed explanatory drawing of the valve control part and abnormality detection part of FR wheel in FIG. 3 is shown. The control flowchart of the control mode judgment part of FIG. 3 is shown. FIG. 4 is a control flowchart when the valve is normal in the control mode determination unit of FIG. The control mode judgment part at the time of an in-valve failure in the control mode judgment part of FIG. 3 is shown. The time chart of a hydraulic pressure when a failure occurs in the front wheel in-valve in the present embodiment is shown. FIG. 4 is a control flowchart when an out valve failure occurs in the control mode determination unit of FIG. 3. FIG. An example in which pressure reduction control is possible from the out-valve of another wheel is shown. The time chart of a hydraulic pressure when a failure occurs in the front wheel out valve in the present embodiment is shown. The control mode determination unit (FIGS. 5 to 7, 9) applied to the hydraulic model in FIG. 1 indicates whether control can be continued for each valve failure part. The hydraulic circuit diagram of the brake device which makes other embodiment of this invention is shown. An example in which the control mode determination unit described in FIG. 5 to FIG. 7 and FIG. 9 is applied to a brake-by-wire that uses two front wheels as an electric hydraulic brake and two rear wheels as an electric brake according to another embodiment of the present invention. Indicates. The time chart at the time of applying the control mode judgment part at the time of an in-valve failure to the hydraulic circuit of FIG. 14 shows whether or not control can be continued for each valve failure site when the control mode determination unit shown in FIGS. 5 to 7 and 9 is applied to the hydraulic model shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Brake pedal 4 Master cylinder 10 Shut off valve 11 In valve 12 Out valve 14 Wheel cylinder 21 Microcomputer 33 Control mode judgment part 34 Each wheel valve control part and abnormality detection part M1 Motor

Claims (8)

A master cylinder that outputs hydraulic pressure according to the amount of operation of the brake operating means;
A wheel cylinder that is installed on each wheel and whose braking force changes according to the hydraulic pressure;
A shutoff valve for communicating / blocking a fluid path between the master cylinder and the wheel cylinder;
A hydraulic pressure source for generating hydraulic pressure in the wheel cylinder based on an operation amount of the brake operating means when the shut-off valve is in a shut-off state;
A brake control device comprising an electromagnetic valve for controlling a hydraulic pressure of the wheel cylinder based on an operation amount of the brake operation means;
An abnormality detection unit for detecting an abnormality in hydraulic pressure control by a shut-off valve or an electromagnetic valve;
A control mode determination unit that determines whether or not transition to the pressure increase control mode, the pressure reduction control mode, and the holding control mode of the wheel cylinder pressure by the shutoff valve and the electromagnetic valve is possible based on the detection result of the abnormality detection unit; ,
Valve control for controlling an energization amount to the electromagnetic valve using a control mode determined to be able to shift by the control mode determination unit so as to generate a wheel cylinder hydraulic pressure corresponding to an operation amount of the brake operation means And
Brake control device comprising: The brake control device according to claim 1,
The abnormality detection unit is configured to detect an abnormality in fluid pressure control by the shutoff valve or the electromagnetic valve based on a current deviation between an actual current value energized to the shutoff valve or the electromagnetic valve and a target current value. Control device. The brake control device according to claim 1,
The control mode determination unit determines whether it is possible to shift to the pressure-increasing control mode, the pressure-reducing control mode, or the holding control mode, based on the failure state of each valve, the target hydraulic pressure of each wheel cylinder, and the actual hydraulic pressure. Brake control device judging from at least one. The brake control device according to claim 1,
The control mode determination unit is set to any one of the pressure increase control mode, the holding control mode, or the pressure reduction control mode based on the operation amount of the brake operation means when a failure occurs in the normally open type in-valve. Brake control device that determines whether to shift. The brake control device according to claim 1,
The control mode determination unit determines whether to shift to either the holding control mode or the pressure-reducing control mode based on the operation amount of the brake operation means when a failure occurs in the normally closed in-valve. Brake control device. The brake control device according to claim 4,
The control mode determination unit is configured to change the backup control mode from the holding control mode or the pressure reduction control mode on condition that the master cylinder pressure is equal to or higher than the wheel cylinder pressure when a failure occurs in the normally closed in-valve. Brake control device to switch to. The brake control device according to claim 1,
The control mode determination unit is based on the operation amount of the brake operation means when a failure occurs in the normally closed type out valve and pressure reduction control is possible by another out valve different from the outage. A brake control device that determines one of the pressure-increasing control mode, the holding control mode, and the pressure-reducing control mode. A master cylinder that outputs hydraulic pressure according to the amount of operation of the brake operating means;
A wheel cylinder that is installed on each wheel and whose braking force changes according to the hydraulic pressure;
A shutoff valve for communicating / blocking a fluid path between the master cylinder and the wheel cylinder;
A hydraulic pressure source for generating hydraulic pressure in the wheel cylinder based on an operation amount of the brake operating means when the shut-off valve is in a shut-off state;
A brake control method comprising: an electromagnetic valve for controlling a hydraulic pressure of the wheel cylinder based on an operation amount of the brake operation means;
Detects abnormalities in hydraulic control by shutoff valves or electromagnetic valves,
Based on the detection result, it is determined whether or not it is possible to shift to the wheel cylinder pressure increasing control mode, the pressure reducing control mode, and the holding control mode by the shutoff valve and the electromagnetic valve,
A brake control method for controlling an energization amount to the electromagnetic valve so as to generate a wheel cylinder hydraulic pressure corresponding to an operation amount of the brake operation means, using a control mode determined to be able to shift.

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