JP2011255864A - Brake control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a brake control device that prevents the occurrence of sealing in of wheel cylinder pressure.SOLUTION: The brake control device 20 includes: a master cylinder unit 27; a first passage 45b that supplies working fluid to at least one of a plurality of wheel cylinders, the wheel cylinders being supplied the working fluid to give braking force to each of a plurality of wheels; a second passage 45a that supplies the working fluid to the rest of the plurality of wheel cylinders; a wheel-cylinder-pressure control system that is connected to the first passage 45b and can commonly control the working fluid pressure of the plurality of wheel cylinders while being independent of an brake operation of a driver; a regulator cut valve 65 that is installed on the first passage 45b, wherein when differential pressure between inlet and outlet exceeds a predetermined pressure during the valve opening, the regulator cut valve is subjected to the action of the differential pressure to be in a valve closing state against a valve opening command; and a brake ECU 70 that determines whether it is supposed the situation where the regulator cut valve 65 is in the valve closing state against the valve opening command.

Description

  The present invention relates to a brake control device that controls braking force applied to wheels provided in a vehicle.

  Patent Document 1 describes a brake control device that enables so-called brake-by-wire braking force control. In order to prevent the containment of wheel cylinder pressure that may occur when the normal brake control mode is switched to the backup brake mode, the hydraulic fluid is discharged from the wheel cylinder. Thereby, the valve opening of the regulator cut valve at the time of mode switching is guaranteed.

JP 2008-87725 A

  Incidentally, the containment of the wheel cylinder pressure may occur not only when the control mode of the brake control device is switched, but also during the control in the brake mode after the switching.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a brake control device in which occurrence of containment of wheel cylinder pressure is suppressed.

  In order to solve the above problems, a brake control device according to an aspect of the present invention includes a manual hydraulic pressure source that pressurizes a stored working fluid in accordance with an operation amount of a brake operation member by a driver, and a supply of the working fluid. A first supply path for supplying working fluid to at least one of the plurality of wheel cylinders that receives and applies braking force to each of the plurality of wheels, and a second supply path for supplying working fluid to the rest of the plurality of wheel cylinders A wheel cylinder pressure control system connected to the first supply path and capable of controlling the hydraulic fluid pressure of the plurality of wheel cylinders in common independently of a driver's brake operation, and provided on the first supply path When the differential pressure between the inlet and the outlet exceeds a predetermined pressure during the valve opening, the differential valve acts to close the valve against the valve opening command, and the valve opens and closes the valve opening command. do it And a control unit determines whether the situation as a valve state is assumed. In the situation where the control unit is in a state where the working fluid is supplied from the manual hydraulic pressure source to the wheel cylinder via the first supply path, the on-off valve is in a closed state against a valve opening command. Is assumed, the flow of the working fluid from the wheel cylinder to the on-off valve is controlled so that the on-off valve does not close.

  According to this aspect, since the situation in which the on-off valve is closed against the valve opening command is determined in advance, the flow of the working fluid from the wheel cylinder to the on-off valve is controlled so that the on-off valve does not close in advance. it can. Therefore, the opening / closing valve is prevented from being closed against the valve opening command by the action of the differential pressure. As a result, the occurrence of containment of the wheel cylinder pressure is suppressed, and for example, dragging of the wheel is prevented.

  A control valve that is opened when the working fluid of the wheel cylinder should be discharged from the first supply path may be further provided. The control unit may reduce the pressure on the wheel cylinder side of the open / close valve by controlling the control valve when a situation where the open / close valve is in a closed state in response to the open command is assumed. . When the pressure is reduced, the pressure on the manual hydraulic pressure source side of the on-off valve decreases, so that the working fluid flows through the on-off valve to the manual hydraulic pressure source side due to the differential pressure. However, if the differential pressure is large, the open / close valve may be closed against the valve opening command. Therefore, by discharging the working fluid from the other control valve instead of the on / off valve, the pressure on the wheel cylinder side of the on / off valve can be reduced to eliminate the differential pressure.

  The control valve is a linear electromagnetic control valve that is provided between the first supply path and a reservoir that stores the working fluid, constitutes the wheel cylinder pressure control system, and controls the flow rate according to the opening of the valve. May be. Thereby, a highly accurate decompression process is possible.

  The pressure on the wheel cylinder side of the on-off valve is P1 [MPa], the pressure on the manual hydraulic pressure source side of the on-off valve is P2 [MPa], and the on-off valve is closed against the valve opening command. When the pressure is X [MPa], the control unit may control energization to the linear electromagnetic control valve with P1 = P2 + A1 (A1 <X) as a target hydraulic pressure. As a result, even when a situation is assumed in which the on-off valve is in a closed state in response to the opening command, the linear electromagnetic control valve The working fluid does not flow out, and unnecessary decompression processing is suppressed.

  The control valve may be provided between the wheel cylinder and a reservoir for storing a working fluid.

  The control valve is provided on the second supply path, and is closed in a state where the working fluid is normally supplied from the manual hydraulic pressure source to the wheel cylinder through the first supply path. The control unit may perform valve opening control of the control valve when a situation is assumed in which the opening / closing valve is in a valve closing state with respect to the valve opening command.

  You may further provide the some control valve which controls the flow of the working fluid between these wheel cylinders and the said on-off valve. The controller may change the pressure reducing method for the plurality of wheel cylinders from a pressure reducing method at a normal time when a situation is assumed in which the on-off valve is in a closed state in response to a valve opening command. When the pressure is reduced, the pressure on the manual hydraulic pressure source side of the on-off valve decreases, so that the working fluid flows through the on-off valve to the manual hydraulic pressure source side due to the differential pressure. However, if the differential pressure is large and the amount of working fluid flowing into the on-off valve is large, the on-off valve may be closed against the valve opening command. Therefore, by changing the depressurization method for multiple wheel cylinders from the normal depressurization method, the amount of working fluid flowing back from the multiple wheel cylinders to the open / close valve is controlled, and the open / close valve closes in response to the open command. The situation that becomes the state can be solved.

  The control unit may control the plurality of control valves so as to reduce a flow of the working fluid flowing from a wheel cylinder having a low pressure among the plurality of wheel cylinders. Thereby, the quantity of the working fluid which flows into an on-off valve can be reduced, and the self-closing of an on-off valve is suppressed. Further, by reducing the flow of the working fluid flowing from the low-pressure wheel cylinder among the plurality of wheel cylinders, priority is given to the decompression of the high-pressure wheel cylinder among the plurality of wheel cylinders, thus causing wheel dragging. The wheel cylinder with high pressure that is easy to pressure is quickly depressurized.

  The controller determines that the target deceleration calculated from the acquired information is decreasing, and the difference between the pressure on the wheel cylinder side of the on-off valve calculated from the acquired information and the pressure on the manual hydraulic pressure source side is The situation where the on-off valve is in a closed state against the valve-opening command exceeds a presumed first predetermined value, and the pressure on the wheel cylinder side of the on-off valve calculated from the acquired information is When at least one of the conditions that the on-off valve exceeds the predetermined pressure at which the on-off valve is closed against the valve-opening command is satisfied, the on-off valve is at the valve-off state against the valve-opening command. It may be determined that the following situation is assumed. As a result, it is possible to accurately determine the situation where the on-off valve is in the closed state against the valve opening command.

  According to the present invention, occurrence of containment of wheel cylinder pressure is suppressed.

1 is a system diagram showing a brake control device according to an embodiment of the present invention. It is a figure which shows typically the change of the hydraulic pressure when a regulator cut valve closes itself. It is a flowchart which shows an example of the execution procedure of the process which determines whether the condition which will be in a valve closing state against a valve opening instruction | indication is assumed.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and repeated descriptions are omitted as appropriate.

(First embodiment)
In one embodiment of the present invention, a brake control device including a plurality of hydraulic pressure paths for introducing hydraulic pressure into a wheel cylinder is provided. The brake control device realizes optimal brake control by using different hydraulic pressure paths depending on the situation. For example, three hydraulic pressure paths are provided in the brake control device. In this case, when the wheel cylinder pressure is controlled by the first hydraulic pressure path, the second hydraulic pressure path and the third hydraulic pressure path are blocked. In each hydraulic pressure path, a control valve is provided between the hydraulic pressure source and the wheel cylinder. Therefore, the brake control device controls the first control valve in the first hydraulic pressure path, and closes the second control valve in the second hydraulic pressure path and the third control valve in the third hydraulic pressure path. The brake control device may control the wheel cylinder pressure by using two or more hydraulic pressure paths together.

  FIG. 1 is a system diagram showing a brake control device 20 according to an embodiment of the present invention. A brake control device 20 shown in the figure constitutes an electronically controlled brake system (ECB) for a vehicle, and controls braking force applied to four wheels provided on the vehicle. The brake control device 20 according to the present embodiment is mounted on, for example, a hybrid vehicle that includes an electric motor and an internal combustion engine as a travel drive source. In such a hybrid vehicle, each of regenerative braking that brakes the vehicle by regenerating kinetic energy of the vehicle into electric energy and hydraulic braking by the brake control device 20 can be used for braking the vehicle. The vehicle in the present embodiment can execute brake regenerative cooperative control in which a desired braking force is generated by using these regenerative braking and hydraulic braking together.

  As shown in FIG. 1, the brake control device 20 includes disc brake units 21FR, 21FL, 21RR and 21RL provided for each wheel, a master cylinder unit 27, a power hydraulic pressure source 30, a hydraulic pressure, Actuator 40.

  Disc brake units 21FR, 21FL, 21RR, and 21RL apply braking force to the right front wheel, the left front wheel, the right rear wheel, and the left rear wheel of the vehicle, respectively. The master cylinder unit 27 as a manual hydraulic pressure source sends the brake fluid pressurized according to the amount of operation by the driver of the brake pedal 24 as a brake operation member to the disc brake units 21FR to 21RL. The power hydraulic pressure source 30 can send the brake fluid as the working fluid pressurized by the power supply to the disc brake units 21FR to 21RL independently from the operation of the brake pedal 24 by the driver. is there. The hydraulic actuator 40 appropriately adjusts the hydraulic pressure of the brake fluid supplied from the power hydraulic pressure source 30 or the master cylinder unit 27 and sends it to the disc brake units 21FR to 21RL. Thereby, the braking force with respect to each wheel by hydraulic braking is adjusted.

  Each of the disc brake units 21FR to 21RL, the master cylinder unit 27, the power hydraulic pressure source 30, and the hydraulic actuator 40 will be described in more detail below. Each of the disc brake units 21FR to 21RL includes a brake disc 22 and wheel cylinders 23FR to 23RL incorporated in the brake caliper, respectively. The wheel cylinders 23FR to 23RL are connected to the hydraulic actuator 40 via different fluid passages. Hereinafter, the wheel cylinders 23FR to 23RL are collectively referred to as “wheel cylinders 23” as appropriate.

  In the disc brake units 21FR to 21RL, when brake fluid is supplied to the wheel cylinder 23 from the hydraulic actuator 40, a brake pad as a friction member is pressed against the brake disc 22 that rotates together with the wheel. Thereby, a braking force is applied to each wheel. Although the disc brake units 21FR to 21RL are used in the present embodiment, other braking force applying mechanisms including a wheel cylinder 23 such as a drum brake may be used.

  The master cylinder unit 27 is a master cylinder with a hydraulic booster in the present embodiment, and includes a hydraulic booster 31, a master cylinder 32, a regulator 33, and a reservoir 34. The hydraulic booster 31 is connected to the brake pedal 24, amplifies the pedal effort applied to the brake pedal 24, and transmits it to the master cylinder 32. When the brake fluid is supplied from the power hydraulic pressure source 30 to the hydraulic pressure booster 31 via the regulator 33, the pedal effort is amplified. The master cylinder 32 generates a master cylinder pressure having a predetermined boost ratio with respect to the pedal effort.

  A reservoir 34 for storing brake fluid is disposed above the master cylinder 32 and the regulator 33. The master cylinder 32 communicates with the reservoir 34 when the depression of the brake pedal 24 is released. On the other hand, the regulator 33 is in communication with both the reservoir 34 and the accumulator 35 of the power hydraulic pressure source 30, and the reservoir 34 is used as a low pressure source, the accumulator 35 is used as a high pressure source, and the hydraulic pressure is approximately equal to the master cylinder pressure. Is generated. Hereinafter, the hydraulic pressure in the regulator 33 is appropriately referred to as “regulator pressure”. The master cylinder pressure and the regulator pressure do not need to be exactly the same pressure. For example, the master cylinder unit 27 can be designed so that the regulator pressure is slightly higher.

  The power hydraulic pressure source 30 includes an accumulator 35 and a pump 36. The accumulator 35 converts the pressure energy of the brake fluid boosted by the pump 36 into the pressure energy of an enclosed gas such as nitrogen, for example, about 14 to 22 MPa and stores it. The pump 36 has a motor 36 a as a drive source, and its suction port is connected to the reservoir 34, while its discharge port is connected to the accumulator 35. The accumulator 35 is also connected to a relief valve 35 a provided in the master cylinder unit 27. When the pressure of the brake fluid in the accumulator 35 increases abnormally to about 25 MPa, for example, the relief valve 35 a is opened, and the high-pressure brake fluid is returned to the reservoir 34.

  As described above, the brake control device 20 includes the master cylinder 32, the regulator 33, and the accumulator 35 as a supply source of brake fluid to the wheel cylinder 23. A master pipe 37 is connected to the master cylinder 32, a regulator pipe 38 is connected to the regulator 33, and an accumulator pipe 39 is connected to the accumulator 35. These master pipe 37, regulator pipe 38 and accumulator pipe 39 are each connected to a hydraulic actuator 40.

  The hydraulic actuator 40 includes an actuator block in which a plurality of flow paths are formed, and a plurality of electromagnetic control valves. The flow paths formed in the actuator block include individual flow paths 41, 42, 43 and 44 and a main flow path 45. The individual flow paths 41 to 44 are respectively branched from the main flow path 45 and connected to the wheel cylinders 23FR, 23FL, 23RR, 23RL of the corresponding disc brake units 21FR, 21FL, 21RR, 21RL. Thereby, each wheel cylinder 23 can communicate with the main flow path 45.

  In addition, ABS holding valves 51, 52, 53 and 54 are provided in the middle of the individual flow paths 41, 42, 43 and 44. Each of the ABS holding valves 51 to 54 has a solenoid and a spring that are ON / OFF controlled, and both are normally open electromagnetic control valves that are opened when the solenoid is in a non-energized state. Each of the ABS holding valves 51 to 54 in the opened state can distribute the brake fluid in both directions. That is, the brake fluid can flow from the main flow path 45 to the wheel cylinder 23, and conversely, the brake fluid can also flow from the wheel cylinder 23 to the main flow path 45. When the solenoid is energized and the ABS holding valves 51 to 54 are closed, the flow of brake fluid in the individual flow paths 41 to 44 is blocked.

  Further, the wheel cylinder 23 is connected to the reservoir channel 55 via pressure reducing channels 46, 47, 48 and 49 connected to the individual channels 41 to 44, respectively. ABS decompression valves 56, 57, 58 and 59 are provided in the middle of the decompression channels 46, 47, 48 and 49. Each of the ABS pressure reducing valves 56 to 59 has a solenoid and a spring that are ON / OFF controlled, and is a normally closed electromagnetic control valve that is closed when the solenoid is in a non-energized state. When the ABS pressure reducing valves 56 to 59 are closed, the flow of brake fluid in the pressure reducing flow paths 46 to 49 is blocked. When the solenoid is energized and the ABS pressure reducing valves 56 to 59 are opened, the brake fluid is allowed to flow through the pressure reducing flow paths 46 to 49, and the brake fluid flows from the wheel cylinder 23 to the pressure reducing flow paths 46 to 49 and It returns to the reservoir 34 via the reservoir channel 55. The reservoir channel 55 is connected to the reservoir 34 of the master cylinder unit 27 via a reservoir pipe 77.

  The main channel 45 has a separation valve 60 in the middle. By this separation valve 60, the main channel 45 is divided into a second channel 45 a connected to the individual channels 41 and 42 and a first channel 45 b connected to the individual channels 43 and 44. The second flow path 45a is connected to the front wheel side wheel cylinders 23FR and 23FL via the individual flow paths 41 and 42, and the first flow path 45b is connected to the rear wheel side wheel cylinder via the individual flow paths 43 and 44. Connected to 23RR and 23RL.

  The separation valve 60 has a solenoid and a spring that are ON / OFF controlled, and is a normally closed electromagnetic control valve that is closed when the solenoid is in a non-energized state. When the separation valve 60 is in the closed state, the flow of brake fluid in the main flow path 45 is blocked. When the solenoid is energized and the separation valve 60 is opened, the brake fluid can be circulated bidirectionally between the first flow path 45b and the second flow path 45a.

  In the hydraulic actuator 40, a master channel 61 and a regulator channel 62 communicating with the main channel 45 are formed. More specifically, the master channel 61 is connected to the second channel 45 a of the main channel 45, and the regulator channel 62 is connected to the first channel 45 b of the main channel 45. The master channel 61 is connected to a master pipe 37 that communicates with the master cylinder 32. The regulator channel 62 is connected to a regulator pipe 38 that communicates with the regulator 33.

  The master channel 61 has a master cut valve 64 in the middle. The master cut valve 64 is provided on the brake fluid supply path from the master cylinder 32 to each wheel cylinder 23. The master cut valve 64 has a solenoid and a spring that are ON / OFF-controlled, and the valve closing state is guaranteed by the electromagnetic force generated by the solenoid when supplied with a prescribed control current, so that the solenoid is in a non-energized state. It is a normally open electromagnetic control valve that is opened in some cases. The master cut valve 64 that has been opened can cause the brake fluid to flow in both directions between the master cylinder 32 and the second flow path 45 a of the main flow path 45. When a prescribed control current is applied to the solenoid and the master cut valve 64 is closed, the flow of brake fluid in the master flow path 61 is interrupted.

  A stroke simulator 69 is connected to the master channel 61 via a simulator cut valve 68 on the upstream side of the master cut valve 64. That is, the simulator cut valve 68 is provided in a flow path connecting the master cylinder 32 and the stroke simulator 69. The simulator cut valve 68 has a solenoid and a spring that are ON / OFF controlled, and the valve opening state is guaranteed by the electromagnetic force generated by the solenoid upon receipt of a specified control current, and the solenoid is in a non-energized state. It is a normally closed electromagnetic control valve that is closed in some cases. When the simulator cut valve 68 is closed, the flow of brake fluid between the master flow path 61 and the stroke simulator 69 is blocked. When the solenoid is energized and the simulator cut valve 68 is opened, the brake fluid can be circulated bidirectionally between the master cylinder 32 and the stroke simulator 69.

  The stroke simulator 69 includes a plurality of pistons and springs, and creates a reaction force corresponding to the depression force of the brake pedal 24 by the driver when the simulator cut valve 68 is opened. As the stroke simulator 69, in order to improve the feeling of brake operation by the driver, it is preferable to employ one having a multistage spring characteristic.

  The regulator flow path 62 has a regulator cut valve 65 in the middle. The regulator cut valve 65 is provided on the brake fluid supply path from the regulator 33 to each wheel cylinder 23. The regulator cut valve 65 also has a solenoid and a spring that are ON / OFF controlled, and the valve closing state is guaranteed by the electromagnetic force generated by the solenoid upon receipt of a specified control current, and the solenoid is in a non-energized state. It is a normally open electromagnetic control valve that is opened in some cases. The regulator cut valve 65 that has been opened can circulate brake fluid bidirectionally between the regulator 33 and the first flow path 45 b of the main flow path 45. When the solenoid is energized and the regulator cut valve 65 is closed, the flow of brake fluid in the regulator flow path 62 is blocked.

  In the hydraulic actuator 40, an accumulator channel 63 is also formed in addition to the master channel 61 and the regulator channel 62. One end of the accumulator channel 63 is connected to the first channel 45 b of the main channel 45, and the other end is connected to an accumulator pipe 39 that communicates with the accumulator 35.

  The accumulator flow path 63 has a pressure-increasing linear control valve 66 in the middle. Further, the accumulator channel 63 and the first channel 45 b of the main channel 45 are connected to the reservoir channel 55 via the pressure-reducing linear control valve 67. The pressure-increasing linear control valve 66 and the pressure-decreasing linear control valve 67 each have a linear solenoid and a spring, and both are normally closed electromagnetic control valves that are closed when the solenoid is in a non-energized state. In the pressure-increasing linear control valve 66 and the pressure-decreasing linear control valve 67, the opening degree of the valve is adjusted in proportion to the current supplied to each solenoid.

  The pressure-increasing linear control valve 66 is provided as a common pressure-increasing control valve for each of the wheel cylinders 23 provided corresponding to each wheel. Similarly, the pressure reducing linear control valve 67 is provided as a pressure reducing control valve common to the wheel cylinders 23. That is, in the present embodiment, the pressure-increasing linear control valve 66 and the pressure-reducing linear control valve 67 are a pair of common controls for controlling supply / discharge of the working fluid sent from the power hydraulic pressure source 30 to each wheel cylinder 23. It is provided as a valve. If the pressure-increasing linear control valve 66 and the like are made common to each wheel cylinder 23 in this way, it is preferable from the viewpoint of cost as compared with the case where a linear control valve is provided for each wheel cylinder 23.

  Here, the differential pressure between the inlet and outlet of the pressure-increasing linear control valve 66 corresponds to the differential pressure between the pressure of the brake fluid in the accumulator 35 and the pressure of the brake fluid in the main flow path 45, and the inlet and outlet of the pressure-reducing linear control valve 67. The pressure difference therebetween corresponds to the pressure difference between the brake fluid pressure in the main flow path 45 and the brake fluid pressure in the reservoir 34. Further, the electromagnetic driving force according to the power supplied to the linear solenoid of the pressure increasing linear control valve 66 and the pressure reducing linear control valve 67 is F1, the spring biasing force is F2, and the pressure increasing linear control valve 66 and the pressure reducing linear control valve are Assuming that the differential pressure acting force according to the differential pressure between the inlet / outlet of 67 is F3, the relationship of F1 + F3 = F2 is established. Therefore, the differential pressure between the inlet and outlet of the pressure-increasing linear control valve 66 and the pressure-reducing linear control valve 67 is controlled by continuously controlling the power supplied to the linear solenoids of the pressure-increasing linear control valve 66 and the pressure-reducing linear control valve 67. can do.

  In the brake control device 20, the power hydraulic pressure source 30 and the hydraulic actuator 40 are controlled by a brake ECU 70 as a control unit in the present embodiment. The brake ECU 70 is configured as a microprocessor including a CPU, and includes a ROM that stores various programs, a RAM that temporarily stores data, an input / output port, a communication port, and the like in addition to the CPU. The brake ECU 70 can communicate with a host hybrid ECU (not shown) and the like, and based on control signals from the hybrid ECU and signals from various sensors, the pump 36 of the power hydraulic pressure source 30 and the hydraulic pressure The electromagnetic control valves 51 to 54, 56 to 59, 60, and 64 to 68 constituting the actuator 40 are controlled.

  Further, a regulator pressure sensor 71, an accumulator pressure sensor 72, and a control pressure sensor 73 are connected to the brake ECU 70. The regulator pressure sensor 71 detects the pressure of the brake fluid in the regulator flow path 62 on the upstream side of the regulator cut valve 65, that is, the regulator pressure, and gives a signal indicating the detected value to the brake ECU 70. The accumulator pressure sensor 72 detects the pressure of the brake fluid in the accumulator flow path 63, that is, the accumulator pressure on the upstream side of the pressure increasing linear control valve 66, and gives a signal indicating the detected value to the brake ECU 70. The control pressure sensor 73 detects the pressure of the brake fluid in the second flow path 45a of the main flow path 45, and gives a signal indicating the detected value to the brake ECU 70. The detection values of the pressure sensors 71 to 73 are sequentially given to the brake ECU 70 every predetermined time, and are stored and held in a predetermined storage area of the brake ECU 70 by a predetermined amount.

  When the separation valve 60 is opened and the first flow path 45 b and the second flow path 45 a of the main flow path 45 communicate with each other, the output value of the control pressure sensor 73 is the low pressure of the pressure-increasing linear control valve 66. The hydraulic pressure on the high pressure side of the pressure-reducing linear control valve 67 and the output pressure value can be used for controlling the pressure-increasing linear control valve 66 and the pressure-reducing linear control valve 67. When the pressure-increasing linear control valve 66 and the pressure-decreasing linear control valve 67 are closed and the master cut valve 64 is opened, the output value of the control pressure sensor 73 indicates the master cylinder pressure. Further, the separation valve 60 is opened so that the first flow path 45b and the second flow path 45a of the main flow path 45 communicate with each other, and the ABS holding valves 51 to 54 are opened, while the ABS pressure reducing valves 56 are opened. When? 59 is closed, the output value of the control pressure sensor 73 indicates the working fluid pressure acting on each wheel cylinder 23, i.e., the wheel cylinder pressure.

  Further, the sensor connected to the brake ECU 70 includes a stroke sensor 25 provided on the brake pedal 24. The stroke sensor 25 detects a pedal stroke as an operation amount of the brake pedal 24 and gives a signal indicating the detected value to the brake ECU 70. The output value of the stroke sensor 25 is also sequentially given to the brake ECU 70 every predetermined time, and is stored and held in a predetermined storage area of the brake ECU 70 by a predetermined amount. A brake operation state detection unit other than the stroke sensor 25 may be provided in addition to the stroke sensor 25 or in place of the stroke sensor 25 and connected to the brake ECU 70. Examples of the brake operation state detection means include a pedal depression force sensor that detects an operation force of the brake pedal 24 and a brake switch that detects that the brake pedal 24 is depressed.

  The brake control device 20 configured as described above can execute brake regeneration cooperative control. The brake control device 20 starts braking in response to a braking request. The braking request is generated when a braking force should be applied to the vehicle, for example, when the driver operates the brake pedal 24. In response to the braking request, the brake ECU 70 calculates a required braking force, and calculates a required hydraulic braking force that is a braking force to be generated by the brake control device 20 by subtracting the braking force due to regeneration from the required braking force. Here, the braking force by regeneration is supplied to the brake control device 20 from the hybrid ECU. Then, the brake ECU 70 calculates the target hydraulic pressure of each wheel cylinder 23FR to 23RL based on the calculated required hydraulic braking force. The brake ECU 70 determines the value of the control current supplied to the pressure-increasing linear control valve 66 and the pressure-decreasing linear control valve 67 based on the feedback control law so that the wheel cylinder pressure becomes the target hydraulic pressure.

  As a result, in the brake control device 20, the brake fluid is supplied from the power hydraulic pressure source 30 to the wheel cylinders 23 via the pressure-increasing linear control valve 66, and braking force is applied to the wheels. Further, brake fluid is discharged from each wheel cylinder 23 through the pressure-reducing linear control valve 67 as necessary, and the braking force applied to the wheel is adjusted. In the present embodiment, a wheel cylinder pressure control system is configured including the power hydraulic pressure source 30, the pressure-increasing linear control valve 66, the pressure-decreasing linear control valve 67, and the like. Braking force control by so-called brake-by-wire is performed by the wheel cylinder pressure control system. The wheel cylinder pressure control system is provided in parallel to the brake fluid supply path from the master cylinder unit 27 to the wheel cylinder 23.

  At this time, the brake ECU 70 closes the regulator cut valve 65 so that the brake fluid sent from the regulator 33 is not supplied to the wheel cylinder 23. Further, the brake ECU 70 closes the master cut valve 64 and opens the simulator cut valve 68. This is because the brake fluid sent from the master cylinder 32 in accordance with the operation of the brake pedal 24 by the driver is supplied not to the wheel cylinder 23 but to the stroke simulator 69. During the brake regeneration cooperative control, a differential pressure corresponding to the magnitude of the regenerative braking force acts between the upstream and downstream of the regulator cut valve 65 and the master cut valve 64.

  The brake control device 20 according to the present embodiment can naturally control the braking force by the wheel cylinder pressure control system even when the required braking force is provided only by the hydraulic braking force without using the regenerative braking force. it can. Regardless of whether or not the brake regeneration cooperative control is executed, the control mode for controlling the braking force by the wheel cylinder pressure control system will be appropriately referred to as a “linear control mode” below. Or it may be called control by brake-by-wire.

  For example, so-called VSC (Vehicle Stability Control) control, TRC (Traction Control) control, and the like for stabilizing the behavior of the vehicle by suppressing the slip of each wheel on the road surface are executed in the linear control mode. VSC control is control for suppressing the side slip of the wheel at the time of turning of the vehicle. The TRC control is a control for suppressing idling of the drive wheels when the vehicle starts or accelerates. In addition, brake assist control that increases the braking force by supplementing the pedaling force by the driver during emergency braking can also be executed in the linear control mode.

  When the required braking force is generated only by the hydraulic braking force in the linear control mode, the hydraulic pressure control is normally performed using the hydraulic pressure obtained based on the brake operation amount as the target hydraulic pressure of the wheel cylinder 23. Further, it is possible to control the hydraulic pressure using the regulator pressure or the master cylinder pressure as the target hydraulic pressure of the wheel cylinder 23. In this case, the hydraulic fluid does not necessarily have to be supplied to the wheel cylinder 23 by the wheel cylinder pressure control system. This is because the required braking force can be naturally generated if the master cylinder pressure or the regulator pressure pressurized according to the operation of the brake pedal by the driver is directly introduced into the wheel cylinder 23.

  For this reason, in the brake control device 20 according to the present embodiment, the hydraulic fluid is supplied from the regulator 33 to each wheel cylinder 23 when the regenerative braking force is not used, for example, when the vehicle is stopped. Hereinafter, the control mode for supplying the hydraulic fluid from the regulator 33 to each wheel cylinder 23 is referred to as “regulator mode”. That is, the brake ECU 70 generates a braking force by switching the control mode from the linear control mode to the regulator mode while the vehicle is stopped.

  In the regulator mode, the brake ECU 70 opens the regulator cut valve 65 and the separation valve 60 and closes the master cut valve 64. The pressure-increasing linear control valve 66 and the pressure-decreasing linear control valve 67 are stopped and closed. The simulator cut valve 68 is opened. As a result, hydraulic fluid is supplied from the regulator 33 to each wheel cylinder 23, and braking force is applied to each wheel by the regulator pressure. Since the power hydraulic pressure source 30 is connected to the regulator 33 on the high pressure side, it is preferable in that the accumulated pressure in the power hydraulic pressure source 30 can be used for generating the braking force.

  As described above, in the regulator mode, the brake ECU 70 stops supplying the control current to the pressure-increasing linear control valve 66 and the pressure-decreasing linear control valve 67 and closes both linear control valves. For this reason, it becomes possible to reduce the operation frequency of the pressure-increasing linear control valve 66 and the pressure-reducing linear control valve 67, and the pressure-increasing linear control valve 66 and the pressure-reducing linear control valve 67 can be used for a long period of time. . That is, the service life of the pressure-increasing linear control valve 66 and the pressure-decreasing linear control valve 67 can be improved.

  Further, during the control in the linear control mode, the wheel cylinder pressure may deviate from the target hydraulic pressure due to occurrence of an abnormality such as a failure, for example. The brake ECU 70 periodically determines the presence or absence of a wheel cylinder pressure response abnormality based on, for example, a measurement value of the control pressure sensor 73. When it is determined that the wheel cylinder pressure control response is abnormal, the brake ECU 70 stops the linear control mode and switches the control mode to the manual brake mode. In the manual brake mode, the driver's input to the brake pedal 24 is converted into hydraulic pressure and mechanically transmitted to the wheel cylinder 23, and braking force is applied to the wheels. The manual brake mode serves as a backup control mode for the linear control mode from the viewpoint of fail-safe.

  The brake ECU 70 can select the manual brake mode from a plurality of modes by changing the supply path from the hydraulic pressure source to the wheel cylinder 23. In the present embodiment, the transition to the non-control mode will be described as an example. In the non-control mode, the brake ECU 70 stops supplying the control current to all the electromagnetic control valves. Therefore, the normally open master cut valve 64 and the regulator cut valve 65 are opened, and the normally closed separation valve 60 and the simulator cut valve 68 are closed. The pressure-increasing linear control valve 66 and the pressure-decreasing linear control valve 67 are stopped and closed.

  As a result, the brake fluid supply path is separated into two systems, the master cylinder side and the regulator side. The master cylinder pressure is transmitted to the wheel cylinders 23FR and 23FL on the front wheel side, and the regulator pressure is transmitted to the wheel cylinders 23RR and 23RL on the rear wheel side. The delivery destination of the working fluid from the master cylinder 32 is switched from the stroke simulator 69 to the wheel cylinders 23FR and 23FL on the front wheel side. The non-control mode is preferable from the viewpoint of fail-safe because a braking force can be generated even when the electromagnetic control valve is not energized due to an abnormality in the control system. In the present embodiment, the supply path on the regulator 33 side corresponds to the first supply path, and the supply path on the master cylinder 32 side corresponds to the second supply path.

  By the way, during the braking control in the regulator mode described above, if the pressure difference between the inlet and the outlet of the on / off valve, in particular the regulator cut valve 65, exceeds a predetermined pressure, the regulator cut by the action of the differential pressure against the valve opening command. There is a possibility that the valve 65 is self-closed and high pressure is confined in the wheel cylinder 23 downstream of the on-off valve. Hereinafter, this predetermined pressure will be appropriately referred to as a self-closing release pressure. If the wheel cylinder pressure is confined, the corresponding wheel is dragged after braking. In the present embodiment, the brake ECU 70 stopping energization of the regulator cut valve 65 corresponds to a valve opening command to the regulator cut valve 65.

  Thus, in a normally open type electromagnetic control valve such as the regulator cut valve 65, a hydraulic pressure exceeding the self-closing release pressure acts between the inlet and outlet in the direction of closing the control valve in the off state, that is, the valve open state. Therefore, even if energization is stopped according to the valve opening command, it cannot return to the valve opening state. This is because the self-closing release pressure is the maximum value of the differential pressure between the inlet and outlet that can be returned to the valve open state by the valve opening force of the return spring built in the control valve. In the present embodiment, when the wheel cylinder 23 on the downstream side has a higher pressure than the regulator 33 on the upstream side, the regulator is cut so that the differential pressure acts between the control valve inlet and outlet in the direction to close the valve. The valve 65 is attached. Hereinafter, this direction is sometimes referred to as a self-closing direction.

  Hereinafter, control for suppressing self-closing of the regulator cut valve 65 in the regulator mode described above will be described. First, the self-closing phenomenon of the regulator cut valve in the regulator mode will be described.

  FIG. 2 is a diagram schematically showing a change in hydraulic pressure when the regulator cut valve is closed. As shown in FIG. 2, in a state where the brake pedal 24 is depressed and a braking force is generated in the regulator mode, the pressure Preg upstream of the regulator cut valve 65 detected by the regulator pressure sensor 71 and the control pressure sensor 73 The detected pressure Pfr of each wheel cylinder 23 is substantially the same.

  In this state, when the depression of the brake pedal 24 is released and the pedal is rapidly returned, the pressure Preg of the regulator cut valve 65 is rapidly reduced. However, the brake fluid existing in the first flow path 45 b and the second flow path 45 a between the regulator cut valve 65 and each wheel cylinder 23 passes through the regulator cut valve 65 and returns to the regulator pipe 38. Therefore, the pressure Pfr of each wheel cylinder 23 decreases more slowly than the pressure Preg, and a differential pressure is generated between the inlet and outlet of the regulator cut valve 65. When the regulator cut valve 65 is closed by this differential pressure, the brake fluid in the first flow path 45b and the second flow path 45a does not flow back to the regulator pipe 38, so the pressure Pfr becomes constant and the wheel cylinder pressure is contained. appear.

  On the other hand, when the regulator cut valve 65 does not self-close, the brake fluid existing in the first flow path 45b and the second flow path 45a thereafter passes through the regulator cut valve 65 and returns to the regulator pipe 38, so that the pressure Pfr is While following the decrease in the pressure Preg, the pressure finally decreases to a value almost equal to the pressure Preg. Therefore, no containment of wheel cylinder pressure occurs.

  The brake control device 20 according to the present embodiment includes a master cylinder unit 27 that pressurizes the stored brake fluid in accordance with the amount of operation of the brake pedal 24 by the driver, and each of a plurality of wheels that receives the supply of the brake fluid. Among the plurality of wheel cylinders 23RR, 23RL, 23FR, and 23FL that apply braking force to the regulator cylinder 62 and the first passage 45b that supply brake fluid to the wheel cylinders 23RR and 23RL, and the brake fluid to the wheel cylinders 23FR and 23FL Cylinder pressure that is connected to the master flow path 61 and the second flow path 45a and the first flow path 45b, and that can commonly control the working fluid pressures of a plurality of wheel cylinders independently of the driver's brake operation. Control system, regulator pipe 38 and first flow path 4 a regulator cut valve 65 which is provided on a path connecting to b, and is closed against the valve opening command by the action of the differential pressure when the pressure difference between the inlet and outlet exceeds a predetermined pressure during valve opening; And a brake ECU 70 that determines whether or not a situation in which the regulator cut valve 65 is in a closed state against the valve opening command is assumed.

  The brake ECU 70 opens the regulator cut valve 65 while the brake fluid is supplied from the master cylinder unit 27 to the plurality of wheel cylinders 23RR, 23RL, 23FR, and 23FL via the regulator pipe 38 and the first flow path 45b. When a situation where the valve is closed against the command is assumed, the inflow of the working fluid from each wheel cylinder 23 to the regulator cut valve 65 is controlled so that the regulator cut valve 65 does not close.

  FIG. 3 is a flowchart illustrating an example of an execution procedure of processing for determining whether or not a situation in which the valve is closed against the valve opening command is assumed. This determination process is periodically repeated after the transition to the regulator mode, and the brake ECU 70 monitors the state of the regulator cut valve 65 and acquires and predicts the open / closed state.

  The brake ECU 70 calculates the target deceleration G1 using both the latest detection value of the regulator pressure sensor 71 and the detection value of the stroke sensor 25 (S10). The brake ECU 70 may calculate a target deceleration using only the detection value of the regulator pressure sensor 71. In addition, the brake ECU 70 may calculate a target deceleration that uses only the detection value of the stroke sensor 25. The brake ECU 70 uses the two calculated target decelerations to calculate one integrated target deceleration G1. Since such a method for calculating the target deceleration is known, a detailed description thereof will be omitted.

  Next, the brake ECU 70 compares the calculated target deceleration G1 with the target deceleration G2 calculated in the previous process to determine whether or not the target deceleration is decreasing (S12). If the target deceleration rate has not decreased (No in S12), the possibility of pressure reduction of the wheel cylinder 23 is low, and the possibility that the regulator cut valve 65 is closed by the differential pressure is low. . On the other hand, when the target deceleration is decreasing (Yes in S12), since the braking force up to that point is not necessary, it is necessary to reduce the pressure of the wheel cylinder 23 in order to reduce the braking force. Therefore, there is a possibility that the regulator cut valve 65 is closed against the valve opening command due to the differential pressure.

  Therefore, in order to further improve the determination accuracy, the brake ECU 70 determines that the difference Pfr−Preg between the pressure Pfr acquired from the control pressure sensor 73 and the pressure Preg acquired from the regulator pressure sensor 71 is the command for opening the regulator cut valve 65. On the other hand, it is determined whether or not the situation where the valve is closed is over a predetermined value A2 (S14). Here, the predetermined value A2 is set with reference to the self-closing release pressure, for example. This is because it is assumed that the regulator cut valve 65 is closed against the valve opening command when the differential pressure is larger than a predetermined value. Therefore, when Pfr−Preg ≦ A2 (No in S14), for example, when the speed of returning the brake pedal 24 is moderate and the change in the pressure Pfr sufficiently follows the change in the pressure Preg, the regulator cut valve 65 is caused by the differential pressure. Therefore, the brake ECU 70 once ends this process. On the other hand, when Pfr-Preg> A2 (Yes in S14), there is a possibility that the regulator cut valve 65 is closed against the valve opening command due to a large differential pressure.

  Therefore, in order to further improve the determination accuracy, the brake ECU 70 determines the value A3 or the self-closing release pressure at which the pressure Pfr acquired from the control pressure sensor 73 becomes the valve closing state against the valve opening command by the regulator cut valve 65. It is determined whether or not it exceeds (S16). Normally, in the regulator mode, the differential pressure generated between the inlet and outlet of the regulator cut valve 65 does not become larger than the pressure detected by the control pressure sensor 73. This is because the pressure on the master cylinder unit 27 side of the regulator cut valve 65 is not at least a negative pressure. Therefore, in the case of Pfr ≦ A3 (No in S16), there is a low possibility that the regulator cut valve 65 self-closes due to the differential pressure, so the brake ECU 70 once ends this process. On the other hand, if Pfr> A3 (Yes in S16), the brake ECU 70 determines that a situation in which the regulator cut valve 65 is closed against the valve opening command due to a large differential pressure is assumed. The process proceeds to the closing suppression process (S18).

  In the process shown in FIG. 3, since a plurality of conditions that may cause the regulator cut valve 65 to be self-closed are determined, it is possible to accurately determine the situation in which the regulator cut valve 65 is in the closed state against the valve opening command. Determined. Note that the brake ECU 70 also determines that a situation is assumed in which the regulator cut valve 65 is closed against the valve opening command when at least one condition of steps S12, S14, and S16 is satisfied. Good. Thereby, the self-closing phenomenon can be surely prevented.

  Next, the self-closing suppression process will be described in detail. As a result of earnestly examining the processing in the case where it is determined that the regulator cut valve 65 is in a closed state against the valve opening command by the above-described method, the present inventors have changed from the wheel cylinder 23 to the regulator cut valve 65. It was conceived that the brake ECU 70 controls the inflow of the brake fluid. That is, the brake control device 20 determines in advance the situation in which the regulator cut valve 65 is closed against the valve opening command, so that the regulator cut from the wheel cylinder 23 is prevented in advance so that the regulator cut valve 65 does not close. The inflow of the brake fluid to the valve 65 can be controlled. Therefore, the regulator cut valve 65 is prevented in advance from closing due to the differential pressure against the valve opening command. As a result, the occurrence of wheel cylinder pressure containment is suppressed, and wheel drag is prevented.

  As described above, when the depressed brake pedal 24 is returned, the pressure on the regulator flow path 62 side of the regulator cut valve 65 decreases, so that the brake fluid passes through the regulator cut valve 65 due to the differential pressure and the regulator flow path 62 side. Will flow to. However, if the differential pressure is large, the regulator cut valve 65 may be closed against the valve opening command.

  The brake control device 20 according to the present embodiment further includes a pressure reducing linear control valve 67 that is opened when the brake fluid of the wheel cylinder 23 should be discharged from the first flow path 45b. The brake ECU 70 controls the pressure-reducing linear control valve 67 to open when the self-closing suppression process in step S18 of FIG. As a result, the brake fluid is returned to the reservoir 34 without passing through the regulator cut valve 65, and the pressure on the wheel cylinder side of the regulator cut valve 65 is reduced. Thus, by discharging the brake fluid from the other control valve instead of the regulator cut valve 65, the pressure on the wheel cylinder side of the regulator cut valve 65 is reduced, and the differential pressure is eliminated. Will be.

  The pressure-reducing linear control valve 67 is a linear electromagnetic control valve that controls the flow rate according to the opening of the valve. Therefore, it is possible to continuously change the flow rate by controlling the opening degree of the valve, and it is possible to perform pressure reduction processing with higher accuracy.

  For example, the pressure on the wheel cylinder 23 side of the regulator cut valve 65 is Pfr [MPa], the pressure on the master cylinder unit 27 side of the regulator cut valve 65 is Preg [MPa], and the regulator cut valve 65 closes against a valve opening command. Assuming that the self-closing release pressure at the valve state is X [MPa], the brake ECU 70 can control energization to the pressure-reducing linear control valve 67 with Pfr = Preg + A1 (A1 <X) as a target hydraulic pressure. As a result, even if a situation is assumed in which the regulator cut valve 65 is in a closed state in response to the valve opening command, the pressure is reduced when the pressure difference that actually closes the regulator cut valve 65 does not occur. Brake fluid does not flow out of the linear control valve 67, and unnecessary decompression processing is suppressed.

  In order to discharge the brake fluid for reducing the pressure on the wheel cylinder side of the regulator cut valve 65, the ABS pressure reducing valve 56 (57, 58, 59) may be used instead of the pressure reducing linear control valve 67 described above. The ABS pressure reducing valve 56 (57, 58, 59) is provided in a pressure reducing flow path 46 (47, 48, 49) between each wheel cylinder 23 and the reservoir 34.

  Further, the master cut valve 64 may be used in place of the pressure reducing linear control valve 67 for discharging the brake fluid for reducing the pressure on the wheel cylinder side of the regulator cut valve 65.

  When it is assumed that the regulator cut valve 65 is in a closed state in response to the valve opening command, the brake ECU 70 is any one of the pressure reducing linear control valve 67 and the ABS pressure reducing valve 56 (57, 58, 59) master cut valve 64. Alternatively, valve opening control may be performed in combination.

(Second Embodiment)
In the first embodiment, when it is assumed that the regulator cut valve 65 is closed in response to the valve opening command, the brake fluid on the wheel cylinder side of the regulator cut valve 65 is not passed through the regulator cut valve 65. By returning to the reservoir, the pressure difference between the inlet and outlet of the regulator cut valve 65 is reduced, and the self-closing of the regulator cut valve 65 due to the differential pressure is suppressed.

  On the other hand, the brake control device according to the present embodiment suppresses self-closing of the regulator cut valve 65 by adjusting the amount of brake fluid that flows into the regulator cut valve 65 when the wheel cylinder is depressurized. .

  As shown in FIG. 1, the brake control device 20 according to the present embodiment includes a plurality of ABS holding valves 51, 52, 53 that control the flow of brake fluid between the plurality of wheel cylinders 23 and the regulator cut valve 65. , 54 are further provided. The brake ECU 70 changes the pressure-reducing method for the plurality of wheel cylinders 23 from the pressure-reducing method at the normal time when a situation is assumed in which the regulator cut valve 65 is closed in response to the valve opening command. Thereby, the amount of brake fluid that flows back from the plurality of wheel cylinders 23 to the regulator cut valve 65 can be controlled, and the situation where the regulator cut valve 65 is in a closed state in response to the valve opening command can be eliminated.

  As a depressurizing method to be changed, the brake ECU 70 selects the ABS holding valves 51, 52, 53, 54, and the separation valve 60 so as to reduce the flow of brake fluid flowing from the wheel cylinder having a low pressure among the plurality of wheel cylinders 23. Close valve control. Thereby, the quantity of the working fluid which flows into the regulator cut valve 65 can be decreased, and the self-closing of the regulator cut valve 65 is suppressed.

  More preferably, when it is assumed that the regulator cut valve 65 is in a closed state in response to the valve opening command, the pressure of the front wheel cylinders 23FR, 23FL is higher than the pressure of the rear wheel wheel cylinders 23RR, 23RL. At this time, the brake ECU 70 controls the ABS holding valves 53 and 54 to close and causes the brake fluid of the front wheel cylinders 23FR and 23FL to flow into the regulator cut valve 65 preferentially.

  Further, when a situation is assumed in which the regulator cut valve 65 is in a closed state in response to the valve opening command, when the pressure of the rear wheel wheel cylinders 23RR, 23RL is higher than the pressure of the front wheel wheel cylinders 23FR, 23FL, The brake ECU 70 controls the ABS holding valves 51 and 52 and the separation valve 60 to close, and causes the brake fluid of the wheel cylinders 23RR and 23RL of the rear wheels to flow into the regulator cut valve 65 with priority.

  In this way, by reducing the flow of the working fluid flowing from the low-pressure wheel cylinder among the plurality of wheel cylinders, priority is given to the decompression of the high-pressure wheel cylinder among the plurality of wheel cylinders. The wheel cylinder having a high pressure that is likely to cause the pressure is quickly reduced.

  As described above, the present invention has been described with reference to the above-described embodiments. However, the present invention is not limited to the above-described embodiments, and the configurations of the embodiments are appropriately combined or replaced. Those are also included in the present invention. Further, it is possible to appropriately change the combination and processing order in each embodiment based on the knowledge of those skilled in the art and to add various modifications such as various design changes to each embodiment. Embodiments to which is added can also be included in the scope of the present invention.

  The regulator 33 generates a fluid pressure substantially equal to the master cylinder pressure using the accumulator 35 as a high pressure source in the regulator mode. In other words, it is difficult for the regulator 33 to generate a hydraulic pressure higher than the pressure of the accumulator 35. Therefore, in the regulator mode, the pressure of the accumulator 35 may be controlled so that a differential pressure exceeding the self-closing release pressure does not occur in the regulator cut valve 65. For example, the brake ECU 70 controls the power hydraulic pressure source 30 so that the pressure of the accumulator 35 becomes lower than the self-closing release pressure after shifting to the regulator mode. As a result, the self-closing phenomenon of the regulator cut valve 65 does not occur in the regulator mode in the first place, and the occurrence of containment of the wheel cylinder pressure is more reliably suppressed.

  20 brake control device, 22 brake disc, 23 wheel cylinder, 24 brake pedal, 25 stroke sensor, 27 master cylinder unit, 30 power hydraulic pressure source, 31 hydraulic booster, 32 master cylinder, 33 regulator, 34 reservoir, 35 accumulator, 37 master pipe, 38 regulator pipe, 39 accumulator pipe, 40 hydraulic actuator, 45a second flow path, 45b first flow path, 46 pressure reducing flow path, 51 ABS holding valve, 56 ABS pressure reducing valve, 60 separation valve, 61 Master flow path, 62 Regulator flow path, 64 Master cut valve, 65 Regulator cut valve, 66 Pressure increase linear control valve, 67 Pressure decrease linear control valve, 70 Brake ECU, 71 Regulator Pressure sensor, 72 Accumulator pressure sensor, 73 Control pressure sensor.

Claims (9)

A manual hydraulic pressure source that pressurizes the stored working fluid according to the amount of operation of the brake operation member by the driver;
A first supply path for supplying the working fluid to at least one of the plurality of wheel cylinders that receives the supply of the working fluid and applies a braking force to each of the plurality of wheels;
A second supply path for supplying a working fluid to the remainder of the plurality of wheel cylinders;
A wheel cylinder pressure control system connected to the first supply path and capable of commonly controlling working fluid pressures of the plurality of wheel cylinders independently of a driver's brake operation;
An on-off valve provided on the first supply path, and when the differential pressure between the inlet and outlet exceeds a predetermined pressure during the valve opening, the valve is closed against the valve opening command by the action of the differential pressure;
A controller that determines whether or not a situation is assumed in which the on-off valve is in a closed state against a valve opening command,
In the situation where the control unit is in a state where the working fluid is supplied from the manual hydraulic pressure source to the wheel cylinder via the first supply path, the on-off valve is in a closed state against a valve opening command. In the brake control device, the flow of the working fluid from the wheel cylinder to the on-off valve is controlled so that the on-off valve does not close. A control valve that is opened when the working fluid of the wheel cylinder is to be discharged from the first supply path;
The controller is configured to reduce the pressure on the wheel cylinder side of the open / close valve by controlling the control valve when a situation is assumed in which the open / close valve is in a closed state with respect to the open command. The brake control device according to claim 1.   The control valve is a linear electromagnetic control valve that is provided between the first supply path and a reservoir for storing a working fluid, and constitutes the wheel cylinder pressure control system and controls a flow rate according to an opening degree of the valve. The brake control device according to claim 2.   The pressure on the wheel cylinder side of the on-off valve is P1 [MPa], the pressure on the manual hydraulic pressure source side of the on-off valve is P2 [MPa], and the on-off valve is closed against the valve opening command. 4. The control unit according to claim 3, wherein when the pressure is X [MPa], the control unit controls energization to the linear electromagnetic control valve by setting P1 = P2 + A1 (where A1 <X) as a target hydraulic pressure. Brake control device.   The brake control device according to claim 2, wherein the control valve is provided between the wheel cylinder and a reservoir for storing a working fluid. The control valve is provided on the second supply path, and is closed in a state where the working fluid is normally supplied from the manual hydraulic pressure source to the wheel cylinder through the first supply path.
3. The brake control device according to claim 2, wherein the control unit performs valve opening control of the control valve when a situation is assumed in which the opening / closing valve is in a closed state in response to a valve opening command. A plurality of control valves for controlling the flow of working fluid between the plurality of wheel cylinders and the on-off valve;
The said control part changes the pressure reduction method of these wheel cylinders from the pressure reduction method at the time of normal, when the condition where the said on-off valve will be in a valve closing state with respect to a valve opening instruction | command is assumed. Item 4. The brake control device according to item 1.   The brake control according to claim 7, wherein the control unit controls the plurality of control valves so as to reduce a flow of a working fluid flowing from a wheel cylinder having a low pressure among the plurality of wheel cylinders. apparatus.   The controller determines that the target deceleration calculated from the acquired information is decreasing, and the difference between the pressure on the wheel cylinder side of the on-off valve calculated from the acquired information and the pressure on the manual hydraulic pressure source side is The situation where the on-off valve is in a closed state against the valve-opening command exceeds a presumed first predetermined value, and the pressure on the wheel cylinder side of the on-off valve calculated from the acquired information is When at least one of the conditions that the on-off valve exceeds the predetermined pressure at which the on-off valve is closed against the valve-opening command is satisfied, the on-off valve is at the valve-off state against the valve-opening command. The brake control device according to claim 1, wherein it is determined that a situation is assumed.

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