JP5907346B2 - Brake control device for vehicle - Google Patents

Description

  The present invention relates to a master cylinder that generates hydraulic pressure in response to an operation of a brake pedal by a driver, a power hydraulic pressure source that generates hydraulic pressure by driving a pressurizing means, and a plurality of electromagnetic valves that are controlled by electrical signals. And a hydraulic pressure output from the master cylinder or the power hydraulic pressure source via the valve mechanism, and a hydraulic pressure output from the master cylinder or the dynamic hydraulic pressure source via the valve mechanism. A wheel cylinder that transmits the braking force to the wheels, a drive circuit that supplies the current to each of the solenoid valves constituting the valve mechanism to drive the solenoid valves, and the valve via the drive circuit. The present invention relates to a brake device for a vehicle including control means for controlling operation of the mechanism.

  Conventionally, for example, a brake system disclosed in Patent Document 1 below is known as a brake device for this type of vehicle. This conventional brake system is provided between a common passage to which a power hydraulic pressure source is connected and each brake cylinder provided in each wheel, and allows the common passage and each brake cylinder to communicate with each other. And a pressure reducing valve for connecting and shutting off each brake cylinder and the reservoir. In this conventional brake system, in order to independently control the hydraulic pressure in each brake cylinder, a holding valve is provided for each brake cylinder, and at least one of these holding valves is normally closed. It is provided as a holding valve.

  Conventionally, for example, a current supply circuit and a brake control device disclosed in Patent Document 2 below are also known. In this conventional current supply circuit and brake control device, a current supply circuit for supplying current from a power source to the simulator cut valve is provided for the brake control device. The current supply circuit includes a first current monitor and a second current monitor that detect a current flowing through the simulator cut valve, and a first regulator disposed in parallel between the power source and the simulator cut valve; The first current monitor and the second current monitor detect the current patterns respectively output from the second regulator, and the regulator in which an abnormality has occurred is determined based on the detected current pattern.

  Conventionally, for example, a brake fluid pressure control device disclosed in Patent Document 3 below is also known. In this conventional brake fluid pressure control device, the controller is supplied from the brake fluid pressure sensor when the fluid pressure control valve is operated in accordance with the operation of the brake pedal to control the brake fluid pressure supplied to the brake wheel cylinder. The minute vibration width of the brake fluid pressure in the brake wheel cylinder is obtained from the detected fluid pressure value, and the operation state of the spool constituting the fluid pressure control valve is estimated by comparing this minute vibration width with a predetermined threshold value. It has become. Then, the controller sets a dither so as to eliminate the fixed state and vibration state of the spool based on the estimation result, and a drive current obtained by superimposing the dither on the target current is supplied to the proportional solenoid constituting the hydraulic pressure control valve. To be controlled.

  Furthermore, conventionally, for example, a brake device, a brake control device, and a brake control method disclosed in Patent Document 4 below are also known. In this conventional brake device, brake control device, and brake control method, after a start-up current for opening the simulator cut valve from the closed state is applied, a steady current for maintaining the open state is continuously applied. To be granted. In the conventional brake device, brake control device, and brake control method, a valve opening current higher than the steady current is applied to the simulator cut valve every time the brake pedal is depressed.

JP 2011-156999 A JP 2011-10019A JP-A-11-99918 JP 2009-23553 A

  In the brake system disclosed in Patent Literature 1, at least one of the holding valves provided for each wheel cylinder uses a normally closed holding valve. This is because the brake system can brake the vehicle by increasing the hydraulic pressure of the wheel cylinder even when, for example, an electrical abnormality or hydraulic fluid leakage occurs in the brake system. This is because the brake system in which the hydraulic fluid leaks is separated from the brake system in which the hydraulic fluid does not leak so that the vehicle can be braked by at least the brake system in which the hydraulic fluid does not leak. By the way, in a situation where no abnormality has occurred in the brake system itself, the hydraulic pressure from the power hydraulic pressure source is transmitted to the wheel cylinder, so that the normally closed holding valve can reliably transmit the hydraulic pressure, that is, the valve is open. If the normally closed holding valve is kept closed for some reason, the hydraulic pressure is not transmitted to the connected wheel cylinder, resulting in braking. Vehicle behavior may become unstable.

  Further, for example, when control for stabilizing the vehicle behavior such as anti-skid control or vehicle stability control is executed, each of the holding valves provided for each wheel cylinder is operated to open and close the wheel cylinder pressure of the wheel cylinder. May be generated by varying the braking force. In this case, if the normally closed holding valve cannot shift to the valve open state, the hydraulic pressure of the connected wheel cylinder cannot be controlled, and as a result, the vehicle behavior does not occur without generating an appropriate braking force. There is a possibility of further instability.

  The present invention has been made to address the above-described problems, and one of its purposes is to reliably open the normally closed electromagnetic on-off valve that constitutes the valve mechanism, and to perform the behavior of the vehicle accompanying braking. An object of the present invention is to provide a brake device for a vehicle that can stabilize the vehicle.

  In order to achieve the above object, a vehicle brake device according to the present invention includes a master cylinder, a power hydraulic pressure source, a valve mechanism, a wheel cylinder, a drive circuit, and control means.

  The master cylinder generates hydraulic pressure in accordance with the operation of the brake pedal by the driver. The power type hydraulic pressure source generates hydraulic pressure by driving a pressurizing means such as a pressurizing pump. When the power hydraulic pressure source has an accumulator, the hydraulic pressure generated by the pressurizing pump can be accumulated in the accumulator. The valve mechanism is composed of a plurality of electromagnetic valves controlled by electrical signals, and the hydraulic pressure output from the master cylinder or the power hydraulic pressure source is transmitted. The wheel cylinder is configured to transmit a hydraulic pressure output from the master cylinder or the power-type hydraulic pressure source via the valve mechanism to apply a braking force to the wheel. The drive circuit supplies current to the electromagnetic valves constituting the valve mechanism to drive the electromagnetic valves. The control means controls the operation of the valve mechanism via the drive circuit.

  In this case, the vehicle brake device may further include a pressure increasing mechanism. The pressure-increasing mechanism is connected to the master cylinder and the power hydraulic pressure source, and uses a hydraulic pressure from the power hydraulic pressure source to achieve a predetermined ratio with respect to the hydraulic pressure from the master cylinder. It generates pressure. Here, the pressure increasing mechanism can be mechanically operated by, for example, a hydraulic pressure output from the master cylinder in accordance with the operation of the brake pedal by the driver.

The vehicle brake device according to the present invention is characterized in that the valve mechanism is provided for each wheel, and an upstream side to which the hydraulic pressure from the power hydraulic pressure source is transmitted and a downstream side to which the wheel cylinder is connected. Among the holding valves that are electromagnetic on-off valves that realize communication or shut-off, the holding means has at least one normally closed holding valve, and the control means is controlled by the wheel cylinder that is not connected to the normally closed holding valve. It is determined whether or not the behavior of the vehicle is unstable based on the state of the wheel to which the braking force is applied, and when the behavior of the vehicle is unstable based on the determination, the normally closed holding valve the compensation current is increased than the current required when maintaining the open state, via the drive circuit is to supply to said normally closed holding valves.

  In this case, the control means is detected by a wheel condition detecting means for detecting a condition of a wheel to which a braking force is applied by the wheel cylinder not connected to the normally closed holding valve, and detected by the wheel condition detecting means. Vehicle behavior determining means for determining whether or not the behavior of the vehicle is unstable based on the state of the wheel that has been determined, and when the vehicle behavior determining means determines that the behavior of the vehicle is unstable Compensation current supply means for supplying a compensation current increased to a current required for maintaining the normally closed holding valve to an open state via the drive circuit to the normally closed holding valve; It is possible to have.

  In this case, the current supplied from the drive circuit to the normally closed holding valve is intermittently supplied by feedforward in order to shift the normally closed holding valve from the closed state to the opened state. And a maintenance current that is continuously supplied by feedback to keep the normally closed holding valve in an open state smaller than the valve opening current, and the control means When the behavior is unstable, a compensation current obtained by increasing the valve opening current for a predetermined time is supplied to the normally closed holding valve via the drive circuit without supplying the maintenance current. be able to. In this case, more specifically, the compensation current supplied from the control means to the normally closed holding valve via the drive circuit can be supplied according to duty control.

  Here, in these cases, as the compensation current, for example, the temperature of the built-in coil used for the opening / closing operation of the normally closed holding valve and the physical quantity representing the behavior of the vehicle (specifically, the yaw rate, the acceleration of the front and rear, the left and right, etc. The valve-opening current can be increased by a variable time determined according to a function using at least one of (2) or a predetermined time.

  In these cases, the control means determines whether or not the behavior of the vehicle is unstable based on the rotational state of the wheel to which the braking force is applied by the wheel cylinder not connected to the normally closed holding valve. Can be determined. Alternatively, in these cases, the control means is based on a behavior change generated in the vehicle due to a rotational state of a wheel to which a braking force is applied by the wheel cylinder that is not connected to the normally closed holding valve. It can be determined whether or not the behavior of is unstable. In this case, the behavior change generated in the vehicle is at least the yaw change generated in the vehicle due to the difference in the rotation state of the wheel to which the braking force is applied, or the difference in the rotation state of the wheel to which the braking force is applied. It can be a change in acceleration generated in the vehicle. In these cases, more specifically, as the rotation state of the wheel, at least a slip state amount indicating a slip state of the wheel (for example, a wheel speed, a slip rate, etc.), or the slip state for each wheel. It can be a difference in quantity, that is, a difference in slip state.

  In these cases, the drive circuit can detect the current flowing through the normally closed holding valve and output the detected current to the control means. The control means can output the detected current output from the drive circuit. Using, it is determined whether or not an abnormality has occurred in the opening and closing operation of the normally closed holding valve, and even in a situation in which no abnormality has occurred in the opening and closing operation of the normally closed holding valve by the determination, When the behavior of the vehicle is unstable, the compensation current can be supplied to the normally closed holding valve via the drive circuit.

  In this case, the drive circuit may have a current monitoring means for detecting a current flowing through the normally closed holding valve. Further, in this case, the control means has abnormality determination means for determining whether an abnormality has occurred in the opening / closing operation of the normally closed holding valve using the detected current detected by the current monitoring means. be able to. In the control means, the vehicle is unstable even when the compensation current supply means determines that no abnormality has occurred in the opening / closing operation of the normally closed holding valve by the abnormality determination means. In this case, the compensation current can be supplied to the normally closed holding valve via the drive circuit.

  According to these, at least when the behavior of the vehicle becomes unstable, for example, a compensation current that is guaranteed to shift to the valve open state can be supplied to the normally closed holding valve. As a result, the normally closed holding valve can be reliably shifted from the closed state to the opened state, and the hydraulic pressure (wheel cylinder pressure) in the wheel cylinder connected to the normally closed holding valve is appropriately controlled. can do. Therefore, it is possible to stabilize the behavior of the vehicle accompanying braking, or to effectively prevent the behavior of the vehicle from becoming more unstable.

  Another feature of the vehicle brake device according to the present invention is that the control means is determined in accordance with at least the magnitude of the braking force applied to the wheel, and is normally closed from the power hydraulic pressure source. A target hydraulic pressure value transmitted to the upstream side of the holding valve, or a detected value of the hydraulic pressure transmitted from the power hydraulic pressure source to the upstream side of the normally closed holding valve, and a predetermined value set in advance. And the compensation current is supplied to the normally closed holding valve via the drive circuit every time the target hydraulic pressure value or the detected value changes by more than the predetermined value.

  In this case, the control means detects a brake operation amount that changes due to the operation of the brake pedal by the driver, and the brake operation detected by the brake operation amount detection means. A target hydraulic pressure transmitted from the power hydraulic pressure source to the upstream side of the normally closed holding valve in accordance with the magnitude of the braking force. Target hydraulic pressure determining means for determining the hydraulic pressure, upstream hydraulic pressure detecting means for detecting the magnitude of hydraulic pressure transmitted from the power hydraulic pressure source to the upstream side of the normally closed holding valve, and the target hydraulic pressure Comparing means for comparing the value of the target hydraulic pressure determined by the determining means or the detected value detected by the upstream hydraulic pressure detecting means with a predetermined value set in advance can be provided. In this case, the compensation current supply means passes the compensation current through the drive circuit each time the value of the target hydraulic pressure or the detection value changes by the comparison means by more than the predetermined value. It can be supplied to a normally closed holding valve.

  According to these, for example, the upstream hydraulic pressure (target hydraulic pressure value or detected value) on the upstream side of the holding valve changes by a predetermined value or more as the driver releases the operation on the brake pedal. In a situation where the value of the side hydraulic pressure decreases by a predetermined value or more, the control means can supply a compensation current to the normally closed holding valve. Therefore, for example, when the driver releases the operation with respect to the brake pedal, the normally closed holding valve can be reliably shifted from the closed state to the opened state, and the wheel cylinder connected to the normally closed holding valve. The hydraulic pressure (wheel cylinder pressure) can be appropriately reduced (depressurized). As a result, the driver does not feel so-called catching with the braking of the vehicle, and an extremely good brake feeling can be obtained.

1 is a schematic system diagram of a vehicle brake device according to an embodiment of the present invention. It is a schematic sectional drawing which shows the structure of the pressure increase mechanism of FIG. It is a figure for demonstrating the linear control mode by the brake device of the vehicle in embodiment of this invention. It is a figure for demonstrating the backup mode at the time of the liquid leak generation | occurrence | production by the brake device of the vehicle in embodiment of this invention. It is a figure for demonstrating the change of the wheel cylinder pressure by this electric current control with respect to the normally closed holding valve when an electric current monitor is normal according to embodiment of this invention. FIG. 4 is a diagram for explaining current control for a normally closed holding valve and a change in wheel cylinder pressure by this current control when an abnormality occurs in the current monitor according to the embodiment of the present invention.

  Hereinafter, a vehicle brake device according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic system configuration diagram of a vehicle brake device according to the present embodiment. The vehicle brake device includes a brake pedal 10, a master cylinder unit 20, a power hydraulic pressure generating device 30, a brake unit 40, a hydraulic pressure control valve device 50, and a brake ECU 100 that manages brake control. The

  The master cylinder unit 20 includes a master cylinder 21 and a reservoir 22. The master cylinder 21 is a tandem type having pressurizing pistons 21a and 21b, and a master cylinder pressure Pmc_FR having a predetermined boost ratio with respect to the pedal depression force input in accordance with the depression operation of the brake pedal 10. , Pmc_FL is generated. A reservoir 22 for storing hydraulic fluid (brake fluid) is provided at the top of the master cylinder 21. Thus, in the master cylinder 21, when the depression operation of the brake pedal 10 is released and the pressure pistons 21a and 21b are retracted, the pressure chambers 21a1 and 21b1 formed by the pressure pistons 21a and 21b are It communicates with the reservoir 22. The pressurizing chambers 21a1 and 21b1 communicate with the hydraulic pressure control valve device 50 via master pressure pipes 11 and 12, which will be described later.

  The power hydraulic pressure generator 30 is a power hydraulic pressure source (power supply), and includes a pressurizing pump 31 and an accumulator 32 as pressurizing means. The pressurizing pump 31 has its suction port connected to the reservoir 22, its discharge port connected to the accumulator 32, and pressurizes the hydraulic fluid by driving the motor 33. The accumulator 32 converts the pressure energy of the hydraulic fluid pressurized by the pressurizing pump 31 into pressure energy of a sealed gas such as nitrogen and stores it. The accumulator 32 is connected to a relief valve 23 provided in the master cylinder unit 20. The relief valve 23 opens when the pressure of the hydraulic fluid rises above a predetermined pressure, and returns the hydraulic fluid to the reservoir 22. In the present embodiment, the power hydraulic pressure generator 30 is provided with a pressurizing pump 31, a motor 33, and an accumulator 32. However, when the power hydraulic pressure generator 30 does not include the accumulator 32, for example, as a pressurizing unit other than the pressurizing pump 31, for example, a cylinder pressurizing device driven by a motor may be employed. Is possible.

  As shown in FIG. 1, the brake unit 40 includes brake units 40FR, 40FL, 40RR, and 40RL provided on each wheel of the vehicle. In the following description, for the configuration provided for each wheel, FR is assigned to the end of the reference symbol, FR for the right front wheel, FL for the left front wheel, RR for the right rear wheel, and RL for the left rear wheel. However, when it is not particularly necessary to specify the wheel position, the last symbol is omitted. The brake units 40FR, 40FL, 40RR, 40RL provided on the respective wheels include brake rotors 41FR, 41FL, 41RR, 41RL and wheel cylinders 42FR, 42FL, 42RR, 42RL built in the brake caliper. Here, the brake unit 40 is not limited to the disc brake type for all four wheels. For example, all the four wheels may be a drum brake type, the front wheel is a disc brake type, the rear wheel is a drum brake type, or the like. Any combination may be used.

    The wheel cylinders 42FR, 42FL, 42RR, 42RL are connected to a hydraulic pressure control valve device 50 so that the hydraulic pressure of the hydraulic fluid supplied via the device 50 is transmitted. Then, the brake pad is pressed against the brake rotors 41FR, 41FL, 41RR, 41RL rotating with the wheels by the hydraulic pressure transmitted (supplied) via the hydraulic control valve device 50, thereby applying a braking force to the wheels.

  The brake device for a vehicle in the present embodiment uses a pedal depression force input via a brake pedal 10 by a driver as a hydraulic pressure source for applying hydraulic pressure to the wheel cylinder 42 via a hydraulic pressure control valve device 50. A master cylinder 21 (or a pressure increasing mechanism 80 to be described later) of the master cylinder unit 20 that applies hydraulic pressure by using the power and a power hydraulic pressure generator 30 that applies hydraulic pressure independently of the master cylinder 21. Prepare. In the vehicle brake device, the master cylinder 21 (more specifically, the pressurizing chambers 21a1, 21b1) and the power hydraulic pressure generator 30 (more specifically, at least the accumulator 32) are respectively connected to the master pressure pipes 11, 12 respectively. And the hydraulic pressure control valve device 50 through the accumulator pressure pipe 13. The reservoir 22 of the master cylinder unit 20 is connected to the hydraulic pressure control valve device 50 via the reservoir pipe 14. In the following description, for the master pressure pipe 12, the upstream side (input side) from the pressure increase mechanism 80 described later is referred to as the master pressure pipe 12 a, and the downstream side (output side) from the pressure increase mechanism 80 is referred to. The master pressure pipe 12b is referred to for distinction.

  The hydraulic control valve device 50 having a valve mechanism includes four individual flow paths 51FR, 51FL, 51RR, 51RL connected to each wheel cylinder 42FR, 42FL, 42RR, 42RL, and individual flow paths 51FR, 51FL, 51RR, 51RL. A main flow path 52 that communicates with each other, master pressure flow paths 53 and 54 that connect the individual flow paths 51FR and 51FL and the master pressure pipes 11 and 12 (12b), and an accumulator pressure flow that connects the main flow path 52 and the accumulator pressure pipe 13 Road 55 is provided. Here, the master pressure channels 53 and 54 and the accumulator pressure channel 55 are respectively connected in parallel to the main channel 52.

  Each individual flow path 51FR, 51FL, 51RR, 51RL is provided with a holding valve 61FR, 61FL, 61RR, 61RL constituting a valve mechanism, respectively. The holding valves 61FL and 61RR provided in the left front wheel side brake unit 40FL and the right rear wheel side brake unit 40RR maintain the valve open state by the spring urging force when the solenoid is not energized. It is a normally open electromagnetic on-off valve that is only closed. On the other hand, the holding valves 61FR and 61RL provided in the brake unit 40FR on the right front wheel side and the brake unit 40RL on the left rear wheel side are kept closed by the biasing force of the spring when the solenoid is not energized, and the solenoid is energized. It is a normally closed electromagnetic on-off valve that is open only inside. Here, in particular, with respect to the holding valve 61FR provided on the front wheel side of the vehicle, the valve opening state is guaranteed by the electromagnetic force generated by the solenoid upon receiving the supply of the prescribed control current (compensation current described later). It has become.

In this way, each holding valve 61 allows the hydraulic fluid to communicate between the main flow path 52 and each wheel cylinder 42 in the valve open state, and between the main flow path 52 and each wheel cylinder 42 in the valve closed state. The communication of hydraulic fluid is prohibited. Accordingly, each holding valve 61 increases (increases) the wheel cylinder pressure Pwc by causing the hydraulic fluid to flow from the main flow path 52 to the respective wheel cylinders 42 via the individual flow paths 51 in the open state. On the other hand, each holding valve 61 shuts off the flow of hydraulic fluid from the main flow path 52 to each wheel cylinder 42 via the individual flow path 51 in the closed state, and from the wheel cylinder 42 via the individual flow path 51. The wheel cylinder pressure Pwc is maintained (held) by blocking the flow of the hydraulic fluid to the passage 52.

  Here, in the holding valves 61FR and 61FL provided in the left and right front wheel side brake units 40FR and 40FL and the holding valves 61RR and 61RL provided in the left and right rear wheel side brake units 40RR and 40RL, one of them is normally open electromagnetic opening and closing. The other is a normally closed electromagnetic on-off valve. That is, the brake unit 40FL corresponding to one of the two wheels at the front and rear diagonal positions and the holding valves 61FL and 61RR provided on the brake unit 40RR are normally open electromagnetic on-off valves, and the other at the front and rear diagonal positions. The brake unit 40FR corresponding to the two wheels and the holding valves 61FR and 61RL provided in the brake unit 40RL are normally closed electromagnetic on-off valves. Therefore, the vehicle brake device in the present embodiment forms a so-called cross system.

In addition, the individual flow paths 56FR, 56FL, 56RR, and 56RL for decompression are connected to the individual flow paths 51FR, 51FL, 51RR, and 51RL, respectively. Each decompression individual channel 56 is connected to a reservoir channel 57. The reservoir channel 57 is connected to the reservoir 22 via the reservoir pipe 14. Each of the individual pressure reducing flow paths 56FR, 56FL, 56RR, 56RL is provided with a pressure reducing valve 62FR, 62FL, 62RR, 62RL constituting the valve mechanism in the middle thereof. The pressure reducing valves 62FR, 62FL, and 62RR are normally closed electromagnetic on-off valves that maintain a valve closed state by a biasing force of a spring when the solenoid is not energized and are opened only when the solenoid is energized. The pressure reducing valve 62RL is a normally open electromagnetic on-off valve that maintains a valve open state by a biasing force of a spring when the solenoid is not energized and is closed only when the solenoid is energized. Each pressure reducing valve 62 reduces (depressurizes) the wheel cylinder pressure Pwc by flowing the hydraulic fluid from the wheel cylinder 42 to the reservoir flow path 57 via the pressure reducing individual flow path 56 in the opened state.

  Master cut valves 63 and 64 are provided in the middle portions of the master pressure channels 53 and 54, respectively. The master cut valves 63 and 64 are normally open electromagnetic on-off valves that are kept open by the biasing force of the spring when the solenoid is not energized and are closed only when the solenoid is energized. By providing the master cut valves 63 and 64 in this way, when the master cut valves 63 and 64 are in the closed state, the connection between the master cylinder 21 (and the pressure increasing mechanism 80) and the wheel cylinders 42FR and 42FL is established. When the master cut valves 63 and 64 are open, the master cylinder 21 (and the pressure increase mechanism 80) and the wheel cylinders 42FR and 42FL are connected when the flow of the hydraulic fluid is prohibited by being blocked. The distribution of hydraulic fluid is allowed.

  The accumulator pressure channel 55 is provided with a pressure-increasing linear control valve 65A in the middle part thereof. Further, a pressure reducing linear control valve 65B is provided between the main channel 52 and the reservoir channel 57 to which the accumulator pressure channel 55 is connected. The pressure-increasing linear control valve 65A and the pressure-decreasing linear control valve 65B maintain the closed state by the biasing force of the spring when the solenoid is not energized, and the valve opening increases as the energization amount (current value) to the solenoid increases. This is a normally closed electromagnetic linear control valve. Although the detailed description of the pressure-increasing linear control valve 65A and the pressure-decreasing linear control valve 65B is omitted, a spring force that the built-in spring urges the valve body in the valve closing direction and a relatively high-pressure hydraulic fluid Expressed as the difference between the differential pressure at which the valve body is urged in the valve opening direction by the differential pressure between the circulating primary side (inlet side) and the secondary side (exit side) through which the relatively low pressure hydraulic fluid flows. The valve closing state is maintained by the valve closing force.

  On the other hand, the pressure-increasing linear control valve 65A and the pressure-decreasing linear control valve 65B are used when the electromagnetic attraction force acting in the direction of opening the valve element generated by energizing the solenoid exceeds the valve closing force, that is, the electromagnetic attraction When force> valve closing force (= spring force-differential pressure) is satisfied, the valve is opened at an opening corresponding to the balance of the force acting on the valve element. Accordingly, the pressure-increasing linear control valve 65A and the pressure-decreasing linear control valve 65B control the differential pressure, that is, the primary side (inlet side) and the secondary side (outlet side) by controlling the energization amount (current value) to the solenoid. The opening according to the differential pressure can be adjusted. In the following description, when there is no need to distinguish between the pressure-increasing linear control valve 65A and the pressure-decreasing linear control valve 65B, they are also simply referred to as the linear control valve 65.

  In the vehicle brake device according to the present embodiment, a stroke simulator 70 is provided for the master pressure pipe 12 (more specifically, the master pressure pipe 12a) connected to the master pressure channel 54 of the hydraulic control valve device 50. Is provided. The stroke simulator 70 includes a piston 70a and a spring 70b, and introduces an amount of hydraulic fluid corresponding to a brake operation amount of the brake pedal 10 by a driver. The stroke simulator 70 allows the driver to operate the brake pedal 10 by displacing the piston 70a against the urging force in accordance with the introduction of the hydraulic fluid into the spring 70b. A reaction force corresponding to the operation amount is generated to improve the brake operation feeling of the driver. The stroke simulator 70 is connected to the master pressure pipe 12 (master pressure pipe 12a) via the simulator flow path 71 and the simulator cut valve 72. In this case, it goes without saying that the stroke simulator 70 can be connected to the master pressure pipe 11.

  In addition, the vehicle brake device according to the present embodiment is provided with a pressure increasing mechanism 80 that increases (servo) the master cylinder pressure Pmc_FL output from the pressure chamber 21b1 of the master cylinder 21 and supplies the pressure to the wheel cylinder 42FL. ing. Here, the pressure increasing mechanism 80 will be described. As the pressure increasing mechanism 80, any structure can be adopted as long as it can increase (servo) the master cylinder pressure Pmc_FL by a mechanical operation as will be described later. In the following, a case where the pressure increasing mechanism 80 is provided in the master pressure pipe 12 will be described as an example, but it goes without saying that the pressure increasing mechanism 80 can be provided in the master pressure pipe 11.

As shown in FIG. 2, the pressure-increasing mechanism 80 includes a housing 81 and a stepped piston 82 that is liquid-tight and slidably fitted to the housing 81, and has a large diameter on the large diameter side of the stepped piston 82. A side chamber 83 is provided, and a small-diameter side chamber 84 is provided on the small-diameter side. The small-diameter side chamber 84 can communicate with the high-pressure chamber 85 connected to the accumulator 32 of the power hydraulic pressure generator 30 via the high-pressure supply valve 86 and the valve seat 87. As shown in FIG. 2, the high-pressure supply valve 86 is pressed against the valve seat 87 by the biasing force of the spring in the high-pressure chamber 85, and is a normally closed valve.

  The small-diameter side chamber 84 is provided with a valve opening member 88 facing the high-pressure supply valve 86, and a spring is disposed between the valve opening member 88 and the stepped piston 82. The biasing force of the spring acts in a direction in which the valve opening member 88 is separated from the stepped piston 82. As shown in FIG. 2, a return spring is provided between the step portion of the stepped piston 82 and the housing 81 to urge the stepped piston 82 in the backward direction. A stopper (not shown) is provided between the stepped piston 82 and the housing 81 so as to regulate the forward end position of the stepped piston 82.

  Further, the stepped piston 82 is formed with a communication passage 89 that allows the large-diameter side chamber 83 and the small-diameter side chamber 84 to communicate with each other. The communication passage 89 allows the large-diameter side chamber 83 and the small-diameter side chamber 84 to communicate with each other while being separated from the valve opening member 88 as shown in FIG. Then, when it comes into contact with the valve opening member 88, it is blocked. With this configuration, the pressure intensifying mechanism 80 operates as a mechanical pressure intensifier (mechanical valve).

  As shown in FIGS. 1 and 2, the high pressure chamber 85 and the power hydraulic pressure generator 30 are connected by a high pressure supply passage 15, and a power hydraulic pressure is generated in the high pressure supply passage 15 together with a pressure increase mechanism cut valve 90. A check valve is provided which allows the flow of hydraulic fluid from the device 30 to the high pressure chamber 85 and prevents reverse flow. The pressure-increasing mechanism cut valve 90 is a normally-open electromagnetic open / close valve that maintains a valve open state by a biasing force of a spring when the solenoid is not energized and is closed only when the solenoid is energized.

  Thus, by providing the pressure increase mechanism cut valve 90, the power hydraulic pressure generator 30 (more specifically, the pressure pump 31 or the accumulator 32) and the high pressure chamber 85 are closed when the solenoid is energized. The transmission of hydraulic pressure between them, that is, the flow of hydraulic fluid is interrupted. Therefore, even if liquid leakage occurs in the pressure increasing mechanism 80 due to a sealing abnormality or the like, the high pressure hydraulic fluid is discharged from the accumulator 32 by maintaining the pressure increasing mechanism cut valve 90 in the closed state. Backflow to the master cylinder 21 via the pressure increase mechanism 80 and the master pressure pipe 12a can be reliably prevented. Further, since the communication (connection) between the accumulator 32 and the high-pressure chamber 85 of the pressure-increasing mechanism 80 via the high-pressure supply passage 15 is interrupted, liquid leakage has occurred in the pressure-increasing mechanism 80 due to an abnormality in the sealing property. Even in this case, it is possible to reliably prevent a decrease (consumption) in the hydraulic pressure in the accumulator 32 (corresponding to an accumulator pressure Pacc described later).

  Further, by providing a check valve in the high pressure supply passage 15, when the hydraulic pressure of the power hydraulic pressure generator 30 (more specifically, the accumulator 32) is higher than the hydraulic pressure of the high pressure chamber 85, the power hydraulic pressure generator is provided. The hydraulic fluid is allowed to flow from 30 to the high pressure chamber 85, but when the hydraulic pressure of the power hydraulic pressure generator 30 is equal to or lower than the hydraulic pressure of the high pressure chamber 85, the valve is closed and bidirectional flow is prohibited. . Therefore, when the pressure increase mechanism cut valve 90 is in the open state, even if liquid leakage occurs in the power hydraulic pressure generator 30, the hydraulic fluid flows back from the high pressure chamber 85 to the power hydraulic pressure generator 30. It is possible to prevent the decrease in the hydraulic pressure of the small-diameter side chamber 84.

  The master pressure pipe 12a and the large-diameter side chamber 83 of the pressure-increasing mechanism 80 are connected by the pilot passage 16, and the pilot-pressure passage 16 and the output side of the pressure-increasing mechanism 80 (that is, the master pressure pipe communicating with the small-diameter side chamber 84). 12b) is provided with a bypass passage 17 that bypasses and connects the pressure increasing mechanism 80. The bypass passage 17 allows a flow of hydraulic fluid from the pilot passage 16 (master pressure pipe 12a) to the master pressure pipe 12b on the output side of the pressure increasing mechanism 80, and prevents a reverse flow. Is provided. Further, a reservoir passage 18 is provided between the space formed by the stepped portion of the stepped piston 82 and the housing 81 and the reservoir pipe 14 communicating with the reservoir 22.

Specifically, the mechanical operation of the pressure-increasing mechanism 80 will be briefly described. In the pressure-increasing mechanism 80, the hydraulic fluid ( When the master cylinder pressure Pmc_FL) is supplied, the hydraulic fluid is supplied to the small-diameter side chamber 84 through the communication path 89. The forward force acting on the stepped piston 82 with the supply of the hydraulic fluid (master cylinder pressure Pmc_FL) (the forward force due to the master cylinder pressure Pmc_FL acting on the large-diameter side chamber 83) is greater than the biasing force of the return spring. When it becomes larger, the stepped piston 82 moves forward. As a result, when the stepped piston 82 contacts the valve opening member 88 and the communication passage 89 is blocked, the hydraulic pressure in the small-diameter side chamber 84 increases as the stepped piston 82 advances, and the pressurized hydraulic fluid is increased. (That is, servo pressure) is output to the master pressure channel 54 of the hydraulic control valve device 50 via the master pressure pipe 12b.

  Further, when the high pressure supply valve 86 is switched to the open state by the advancement of the valve opening member 88, the high pressure hydraulic fluid is supplied from the high pressure chamber 85 to the small diameter side chamber 84, and the hydraulic pressure in the small diameter side chamber 84 becomes higher. In this case, the pressure-increasing mechanism cut valve 90 is opened, and the hydraulic fluid pressure (accumulator pressure Pacc) stored in the accumulator 32 of the power hydraulic pressure generator 30 is greater than the hydraulic pressure in the high-pressure chamber 85. If it is higher, the hydraulic pressure of the accumulator 32 (accumulator pressure Pacc) is supplied to the high pressure chamber 85 via the check valve of the high pressure supply passage 15 and supplied to the small diameter side chamber 84. In the stepped piston 82, the hydraulic pressure of the large-diameter side chamber 83, that is, the master cylinder pressure Pmc_FL, acts on the large-diameter side (master cylinder pressure Pmc_FL × pressure receiving area) and on the small-diameter side (servo pressure × The output is adjusted to a size that balances the pressure receiving area. Therefore, it can be said that the pressure increasing mechanism 80 is a mechanical booster mechanism.

  On the other hand, when the pressure-increasing mechanism cut valve 90 is opened and the hydraulic pressure in the accumulator 32 (accumulator pressure Pacc) is equal to or lower than the hydraulic pressure in the high-pressure chamber 85, the reverse provided in the high-pressure supply passage 15 is provided. Since the stop valve prevents the flow of hydraulic fluid between the accumulator 32 and the high pressure chamber 85, the stepped piston 82 cannot advance further. Further, the stepped piston 82 may not be able to move forward by contacting the stopper. In this state, when the master cylinder pressure Pmc_FL supplied from the master cylinder 21 increases and becomes higher than the hydraulic pressure in the small-diameter side chamber 84, the master cylinder pressure Pmc_FL is supplied to the master pressure pipe 12b through the bypass passage 17 and the check valve. Is done.

  The power hydraulic pressure generating device 30 and the hydraulic pressure control valve device 50 are driven and controlled by a brake ECU 100 as control means. The brake ECU 100 includes a microcomputer including a CPU, ROM, RAM, and the like as main components. In addition to the electromagnetic valve driving circuit 100a, the brake ECU 100 includes a pump driving circuit, an interface for inputting various sensor signals, a communication interface, and the like. I have. All the solenoid on-off valves 61 to 64, 72, 90 and the linear control valve 65 provided in the hydraulic control valve device 50 are all connected to the brake ECU 100 via the solenoid valve drive circuit 100a, and are output from the brake ECU 100. The open / close state and the opening degree (in the case of the linear control valve 65) are controlled by the drive signal (current). Here, in particular, the electromagnetic valve drive circuit 100a is provided with a current detection circuit 100a1 for detecting a current supplied to the holding valve 61FR, that is, a current monitor circuit, and represents a current value detected by the current monitor circuit. A detection signal is output to the brake ECU 100. The motor 33 provided in the power hydraulic pressure generator 30 is connected to the brake ECU 100 via a pump drive circuit, and is driven and controlled by a motor drive signal output from the brake ECU 100.

  The hydraulic pressure control valve device 50 is provided with an accumulator pressure sensor 101, master cylinder pressure sensors 102 and 103, and a control pressure sensor 104. The accumulator pressure sensor 101 is the hydraulic fluid pressure in the accumulator pressure channel 55 on the power hydraulic pressure generator 30 side (upstream side) from the pressure-increasing linear control valve 65A, that is, the accumulator pressure channel 55 is connected via the accumulator pressure pipe 13. Therefore, the accumulator pressure Pacc is detected. The accumulator pressure sensor 101 outputs a signal representing the detected accumulator pressure Pacc to the brake ECU 100. Thereby, the brake ECU 100 reads the accumulator pressure Pacc in a predetermined cycle, and when the accumulator pressure Pacc falls below a preset minimum set pressure, the brake ECU 100 drives the motor 33 to pressurize the hydraulic fluid by the pressurizing pump 31, Control is performed so that the accumulator pressure Pacc is always maintained within the set pressure range.

  The master cylinder pressure sensor 102 is hydraulic fluid pressure in the master pressure channel 53 on the master cylinder 21 side (upstream side) from the master cut valve 63, that is, the master pressure channel 53 is connected to the pressurizing chamber via the master pressure pipe 11. Since it communicates with 21a1, the master cylinder pressure Pmc_FR is detected. The master cylinder pressure sensor 103 is a hydraulic fluid pressure in the master pressure channel 54 on the master cylinder 21 side (upstream side) from the master cut valve 64, that is, the master pressure channel 54 is pressurized through the master pressure pipe 12. Since it communicates with 21b1, the master cylinder pressure Pmc_FL is detected. Master cylinder pressure sensors 102 and 103 output signals representing detected master cylinder pressures Pmc_FR and Pmc_FL to brake ECU 100.

  The control pressure sensor 104 as the upstream hydraulic pressure detection means is the hydraulic pressure of the hydraulic fluid in the main flow path 52 that is upstream of each wheel cylinder 42 (that is, the hydraulic pressure transmitted to the upstream side. This is also referred to as “upstream hydraulic pressure”.) Is detected as the control pressure Px. Then, the control pressure sensor 104 outputs a signal representing the detected control pressure Px to the brake ECU 100.

  In addition, a stroke sensor 105 provided on the brake pedal 10 is connected to the brake ECU 100. The stroke sensor 105 outputs a signal representing the pedal stroke Sm, which is the depression amount (operation amount) of the brake pedal 10 by the driver, to the brake ECU 100. A wheel speed sensor 106 is connected to the brake ECU 100. The wheel speed sensor 106 detects the wheel speed Vxi (i = FR, FL, RR, RL) that is the rotational speed of the left and right front and rear wheels, and represents the detected wheel speed Vxi (i = FR, FL, RR, RL). A signal is output to the brake ECU 100. Further, the brake ECU 100 is connected to a behavior change amount detection sensor 107 that detects a physical quantity related to a behavior change generated in the vehicle due to a difference in the rotation state of the wheels. The behavior change amount detection sensor 107 specifically detects the yaw rate γ and the acceleration G as physical quantities related to the behavior change of the vehicle, and outputs a signal representing the detected physical quantity to the brake ECU 100.

  Next, brake control executed by the brake ECU 100 will be described. The brake ECU 100 regulates the hydraulic pressure (more specifically, the accumulator pressure Pacc) output from the power hydraulic pressure generator 30 by the linear control valve 65 and transmits the pressure to each wheel cylinder 42 via the main flow path 52. (4S mode) and the master cylinder pressures Pmc_FR and Pmc_FL generated in the master cylinder 21 according to the pedaling force applied to the brake pedal 10 by the driver are transmitted to the wheel cylinders 42FR and 42FL on the left and right front wheels, or the linear control valve 65 The brake control is selectively executed in two control modes of the backup mode (2S mode) in which the accumulator pressure Pacc regulated by the above is transmitted to the wheel cylinders 42RR and 42RL on the left and right rear wheels.

  First, in the linear control mode, as shown in FIG. 3, the brake ECU 100 maintains the normally-open master cut valves 63 and 64 in a closed state by energizing the solenoid, and sets the simulator cut valve 72 to the solenoid. Keep the valve open by energization. Further, in the linear control mode in the present embodiment, the brake ECU 100 maintains the normally-open pressure-increasing mechanism cut valve 90 in a closed state by energizing the solenoid.

  In the linear control mode, the brake ECU 100 controls the energization amount (current value) to the solenoids of the pressure-increasing linear control valve 65A and the pressure-reducing linear control valve 65B, and controls the opening according to the energization amount. The brake ECU 100 maintains the normally open holding valves 61FL and 61RR in the open state, and maintains the normally closed holding valves 61FR and 61RL in the open state by energizing the solenoid. Here, in particular, with respect to the normally closed holding valve 61FR, the brake ECU 100 may shift the holding valve 61FR to the open state in accordance with the valve opening control described in detail later. Further, the brake ECU 100 maintains the normally closed pressure reducing valves 62FR, 62FL, 62RR in the closed state and maintains the normally opened pressure reducing valve 62RL in the closed state by energizing the solenoid.

  In this way, in the linear control mode, the master cut valves 63 and 64 are both closed by controlling the open or closed state of each solenoid valve (electromagnetic on-off valve) constituting the hydraulic pressure control valve device 50. Since the valve state is maintained, the master cylinder pressures Pmc_FR and Pmc_FL output from the master cylinder 21 are not transmitted to the wheel cylinders 42FR and 42FL. Further, since the pressure increase mechanism cut valve 90 is maintained in the closed state, the accumulator pressure Pacc output from the pressure pump 31 or the accumulator 32 of the power hydraulic pressure generator 30 is not transmitted to the pressure increase mechanism 80. Therefore, in the linear control mode, the high pressure accumulator pressure Pacc is increased from the high pressure chamber 85 of the pressure increasing mechanism 80 through the small diameter side chamber 84, the communication passage 89, the large diameter side chamber 83, the pilot passage 16 and the master pressure pipe 12 (12a). Is prevented from being transmitted to the master cylinder 21.

  On the other hand, since the pressure-increasing linear control valve 65A and the pressure-decreasing linear control valve 65B are in the solenoid energization control state, the high-pressure accumulator pressure Pacc output from the power hydraulic pressure generator 30 on the upstream side of the holding valve 61 increases. The pressure linear control valve 65 </ b> A and the pressure-reducing linear control valve 65 </ b> B adjust the upstream hydraulic pressure, that is, the control pressure Px, and transmit the pressure to the four-wheel wheel cylinder 42 on the downstream side of the holding valve 61. In this case, since the holding valve 61 is maintained in the open state and the pressure reducing valve 62 is maintained in the closed state, the wheel cylinder pressure Pwc of each wheel cylinder 42 is the same value as the control pressure Px in the main flow path 52. It becomes.

  By the way, the vehicle provided with the brake device of the vehicle of the present embodiment is, for example, an electric vehicle (EV) provided with a running motor driven by a battery power source, or a hybrid provided with an internal combustion engine in addition to the running motor. It can be set as the plug-in hybrid vehicle (PHV) which can charge a battery further using an external power supply with respect to a vehicle (HV) and a hybrid vehicle (HV). In such a vehicle, it is possible to generate regenerative braking by generating a braking force by generating power by converting the rotational energy of the wheels into electric energy by a traveling motor and regenerating the generated power in a battery. When performing such regenerative braking, regenerative braking and hydraulic braking are performed by generating in the vehicle braking device a braking force obtained by removing the braking force due to regeneration from the total braking force required for braking the vehicle. Brake regenerative cooperative control can be performed in combination.

  Specifically, the brake ECU 100 starts the brake regeneration cooperative control in response to the braking request. The braking request should be applied to the vehicle, for example, when the driver depresses the brake pedal 10 (hereinafter simply referred to as “brake operation”) or when there is a request to activate the automatic brake. Occurs when. Here, the automatic brake may be operated in traction control, vehicle stability control, inter-vehicle distance control, collision avoidance control, or the like, and a braking request is generated when these control start conditions are satisfied.

  Upon receiving a braking request, the brake ECU 100 detects the brake operation amount by the master cylinder pressure Pmc_FR detected by the master cylinder pressure sensor 102, the master cylinder pressure Pmc_FL detected by the master cylinder pressure sensor 103, and the stroke sensor 105. At least one of the pedal strokes Sm is acquired, and a target braking force that increases as the master cylinder pressure Pmc_FR, the master cylinder pressure Pmc_FL and / or the pedal stroke Sm increases is calculated. For the brake operation amount, instead of acquiring the master cylinder pressure Pmc_FR, the master cylinder pressure Pmc_FL and / or the pedal stroke Sm, for example, a pedal force sensor for detecting the pedal depression force with respect to the brake pedal 10 is provided, It is also possible to calculate the target braking force based on the above.

  The brake ECU 100 transmits information representing the calculated target braking force to the hybrid ECU (not shown). The hybrid ECU calculates a braking force generated by power regeneration from the target braking force, and transmits information representing the regenerative braking force, which is the calculation result, to the brake ECU 100. Accordingly, the brake ECU 100 calculates a target hydraulic braking force that is a braking force that should be generated by the brake unit 40 by subtracting the regenerative braking force from the target braking force. Here, the regenerative braking force generated by the power regeneration performed by the hybrid ECU does not change due to the rotation speed of the motor, but also changes due to the regenerative power control depending on the state of charge (SOC) of the battery. To do. Accordingly, an appropriate target hydraulic braking force can be calculated by subtracting the regenerative braking force from the target braking force.

  Based on the calculated target hydraulic braking force, the brake ECU 100 calculates the target hydraulic pressure of each wheel cylinder 42 corresponding to the target hydraulic braking force, and the control pressure Px (that is, the wheel cylinder pressure Pwc) is the target hydraulic pressure. A solenoid drive signal is supplied by feedback control so as to be equal to the pressure, and the drive current of the pressure-increasing linear control valve 65A and the pressure-decreasing linear control valve 65B is controlled. That is, the brake ECU 100 sets the energization amount (current value) to the solenoids of the pressure increasing linear control valve 65A and the pressure reducing linear control valve 65B so that the control pressure Px detected by the control pressure sensor 104 follows the target hydraulic pressure. Control.

  Thus, in the linear control mode, hydraulic fluid is supplied from the power hydraulic pressure generator 30 to each wheel cylinder 42 via the pressure-increasing linear control valve 65A and the main flow path 52, and the wheel cylinder pressure Pwc is increased to the wheel. Generate braking force. Further, in the linear control mode, the hydraulic fluid is discharged from the wheel cylinder 42 to the reservoir flow path 57 through, for example, the main flow path 52 and the pressure-reducing linear control valve 65B, so that the wheel cylinder pressure Pwc is reduced to the wheel. The generated braking force can be adjusted appropriately.

  For example, when the brake operation by the driver is released, the energization to the solenoids of all solenoid valves (electromagnetic on-off valves) constituting the hydraulic pressure control valve device 50 is cut off, so that all the solenoid valves (solenoids) The on-off valve is returned to the original position shown in FIG. In this way, when all the solenoid valves (electromagnetic on-off valves) are returned to their original positions, the hydraulic pressure (working fluid) of the wheel cylinder 42FR of the right front wheel is in the open state, and the master cut valve 63 and the master pressure pipe 11 are in the open state. After that, it is returned to the master cylinder 21 and the reservoir 22. The hydraulic pressure (hydraulic fluid) of the left front wheel wheel cylinder 42FL passes through the master cut valve 64 in the open state, the communication passage 89 of the pressure increasing mechanism 80, the pilot passage 16 and the master pressure pipe 12 (12a), and the master cylinder 21 and Returned to reservoir 22.

  The hydraulic pressure (hydraulic fluid) of the wheel cylinder 42RR of the right rear wheel is the holding valve 61RR in the opened state, the main flow path 52, the holding valve 61FL in the opened state, the master cut valve 64 in the opened state, and the pressure increase. It is returned to the master cylinder 21 and the reservoir 22 through the communication passage 89 of the mechanism 80, the pilot passage 16 and the master pressure pipe 12 (12a). The hydraulic pressure (hydraulic fluid) in the wheel cylinder 42RL of the left rear wheel is returned to the reservoir 22 via the pressure reducing valve 62RL and the reservoir channel 57 that are open.

  Here, with respect to the wheel cylinder 42RL, in order to prevent the hydraulic fluid from the master cylinder 21 and the pressure increasing mechanism 80 from being supplied when an abnormality occurs in a control system (electrical system) described later, the holding valve 61RL is a normally closed electromagnetic. It is an on-off valve. For this reason, when the brake operation is released, the wheel cylinder 42RL is disconnected from the main flow path 52, and the hydraulic fluid cannot be returned to the master cylinder 21 via the pressure increasing mechanism 80. On the other hand, since the pressure reducing valve 62RL is a normally open electromagnetic opening / closing valve, the hydraulic fluid of the wheel cylinder 42RL can be returned to the reservoir 22 via the pressure reducing valve 62RL. In addition, when the pressure reducing valve is a normally open solenoid valve, current must be continuously supplied to the solenoid in the linear control mode in order to maintain the valve closed state, resulting in a problem that power consumption increases. To do. However, in this embodiment, since the normally open pressure reducing valve is one of the pressure reducing valves 62RL, an increase in power consumption can be suppressed.

  It should be noted that the present invention does not necessarily require that the brake regenerative cooperative control be performed, and needless to say, can be applied to a vehicle that does not generate a regenerative braking force. In this case, the target hydraulic pressure may be directly calculated based on the brake operation amount. The target hydraulic pressure is set to a larger value as the brake operation amount increases, for example, using a map or a calculation formula.

  Next, the backup mode will be described as an example. In a vehicle brake device, the brake ECU 100 performs a predetermined initial check. By this initial check, for example, an abnormal operation of the brake ECU 100 itself, disconnection of each electromagnetic valve (each electromagnetic on-off valve), and the like. When an abnormality is detected in the control system (electrical system) or the possibility of leakage of hydraulic fluid is detected, the brake ECU 100 activates the brake ECU 100 of the vehicle in the backup mode to generate braking force on the wheels. Let

  First, when an abnormality is detected in the control system (electric system), the brake ECU 100 cuts off the power supply to all the electromagnetic valves (electromagnetic on-off valves), and all the electromagnetic valves (electromagnetic on-off valves) are shown in FIG. Return to the original position. As a result, the pressure-increasing linear control valve 65A and the pressure-decreasing linear control valve 65B are closed when the solenoid is de-energized, and the power hydraulic pressure generator 30 is connected to each wheel cylinder 42 via the main flow path 52. Is cut off from. Further, since the pressure increase mechanism cut valve 90 is opened, the pressure increase mechanism 80 communicates with the accumulator 32. Further, the holding valve 61FR and the holding valve 61RL are closed, and the holding valve 61FL and the holding valve 61RR are opened. Therefore, the wheel cylinder 42FL for the left front wheel and the wheel cylinder 42RR for the right rear wheel communicate with each other via the main flow path 52, and the wheel cylinder 42FR for the right front wheel and the wheel cylinder 42RL for the left rear wheel communicate with the main flow path 52. Blocked.

  In this state, when the brake operation of the brake pedal 10 is performed by the driver, the hydraulic fluid in the pressurizing chambers 21a1 and 21b1 of the master cylinder 21 is pressurized. Thereby, the hydraulic pressure (master cylinder pressure Pmc_FR) in the pressurizing chamber 21a1 is supplied to the wheel cylinder 42FR of the right front wheel through the master pressure pipe 11, the master pressure flow path 53, and the master cut valve 63 in the valve open state. The brake unit 40FR can be operated satisfactorily.

  On the other hand, the hydraulic pressure (master cylinder pressure Pmc_FL) in the pressurizing chamber 21b1 is supplied to the pressure increasing mechanism 80 via the master pressure pipe 12 (12a) and the pilot passage 16, and the pressure increasing mechanism 80 starts operating. That is, in the pressure increasing mechanism 80, the stepped piston 82 moves forward, the communication through the communication path 89 between the small diameter side chamber 84 and the large diameter side chamber 83 is blocked by the valve opening member 88, and the hydraulic pressure in the small diameter side chamber 84 is Will increase. When the valve-opening member 88 moves forward and the high-pressure supply valve 86 is opened, high-pressure hydraulic fluid is supplied from the accumulator 32 into the high-pressure chamber 85 via the pressure-increasing mechanism cut valve 90 that is open. The accumulator pressure Pacc is transmitted to the small diameter side chamber 84.

As a result, the hydraulic pressure (servo pressure) in the small-diameter side chamber 84 is made higher than the master cylinder pressure Pmc_FL, and left via the master pressure pipe 12 (12b), the master pressure flow path 54, and the master cut valve 64 in the valve open state. While being supplied to the wheel cylinder 42FL of the front wheel, it is supplied to the wheel cylinder 42RR of the right rear wheel via the holding valve 61FL, the main flow path 52 and the holding valve 61RR. Accordingly, the servo pressure higher than the master cylinder pressure Pmc_FL is supplied to the left front wheel cylinder 42FL and the right rear wheel cylinder 42RR, whereby the brake unit 40FL and the brake unit 40RR can be operated satisfactorily.

  In this state, the pressure pump 31 of the power hydraulic pressure generating device 30 is in a stopped state, so that the hydraulic pressure of the accumulator 32 (accumulator pressure Pacc) gradually decreases. For this reason, when the accumulator pressure Pacc becomes equal to or lower than the hydraulic pressure in the high pressure chamber 85, the check valve provided in the high pressure supply passage 15 prevents the flow of hydraulic fluid from the high pressure chamber 85 to the accumulator 32. 82 is prevented from advancing, and the hydraulic pressure in the small-diameter side chamber 84 does not increase any more, and the pressure-increasing mechanism 80 cannot perform the boosting function. When the hydraulic pressure in the pressurizing chamber 21b1 of the master cylinder 21 (master cylinder pressure Pmc_FL) becomes higher than the hydraulic pressure in the small-diameter side chamber 84 by the pedal depression force of the driver on the brake pedal 10, the master cylinder pressure Pmc_FL is changed to the bypass passage 17, The master pressure pipe 12b, the master pressure flow path 54, the master cut valve 64, the holding valve 61FL, the main flow path 52, and the holding valve 61RR are supplied to the left front wheel cylinder 42FL and the right rear wheel wheel cylinder 42RR.

  As described above, in the present embodiment, the servo pressure (or master cylinder pressure Pmc_FL) is selectively supplied to the wheel cylinders 42FL and 42RR of the two wheels (left front wheel and right rear wheel) that are diagonal to each other. To do. Thus, yaw (yaw moment) is hardly generated in the vehicle, and the two brake units 40FL and 40RR can be operated favorably. Note that the hydraulic pressure (master cylinder pressure Pmc_FR) is supplied to the right front wheel wheel cylinder 42FR from the pressurizing chamber 21a1 of the master cylinder 21 through the master cut valve 63 in the valve open state, as described above.

  Therefore, in the present embodiment, when the control system (electric system) is abnormal, the hydraulic pressure (master cylinder pressure Pmc_FR, Pmc_FL) of the master cylinder 21 or the pressure increasing mechanism 80 is applied to the three wheel cylinders 42FR, 42FL, 42RR. By supplying the hydraulic pressure (servo pressure), the braking force of the vehicle as a whole can be increased as compared with the case where the hydraulic pressure is supplied to the two wheel cylinders. While the pressure increasing mechanism 80 is operating, the servo pressure greater than the master cylinder pressure Pmc_FR, which is substantially equal to the master cylinder pressure Pmc_FL, is applied to the left front wheel cylinder 42FL and the right rear wheel cylinder 42RR. Therefore, yaw (yaw moment) can be further prevented from being generated.

  Next, the backup mode when the possibility of liquid leakage is detected will be described. In the linear control mode, the brake ECU 100 is based on, for example, a change (decrease) in the accumulator pressure Pacc or the control pressure Px (corresponding to the wheel cylinder pressure Pwc) detected by the accumulator pressure sensor 101 or the control pressure sensor 104. When the possibility of liquid leakage is detected in the brake device, as a general rule, the electromagnetic on-off valves are opened and closed as shown in FIG. That is, the brake ECU 100 closes the left and right front wheel holding valves 61FR and 61FL, opens the left and right rear wheel holding valves 61RR and 61RL, and opens the master cut valves 63 and 64. The brake ECU 100 closes the simulator cut valve 72, maintains the pressure increase mechanism cut valve 90 in the closed state, and closes all the pressure reducing valves 62.

  Thereby, the wheel cylinder 42RR and the wheel cylinder 42RL of the left and right rear wheels are connected to the power hydraulic pressure generator via the holding valves 61RR and 61RL, the main flow path 52, the pressure-increasing linear control valve 65A, the accumulator pressure flow path 55, and the accumulator pressure pipe 13. It communicates with 30 pressure pumps 31 and / or accumulators 32. For this reason, in the wheel cylinders 42RR and 42RL, the high accumulator pressure Pacc is adjusted to the control pressure Px by the pressure-increasing linear control valve 65A and the pressure-reducing linear control valve 65B and transmitted to the wheel cylinders 42RR and 42RL.

  On the other hand, the wheel cylinder 42FR of the right front wheel communicates with the pressurizing chamber 21a1 of the master cylinder 21 through the master cut valve 63, the master pressure passage 53 and the master pressure pipe 11, and the hydraulic pressure is set to the master cylinder pressure Pmc_FL. That is, in this situation, the hydraulic fluid (in other words, the master cylinder pressure Pmc_FR) directly transmitted from the pressurizing chamber 21a1 of the master cylinder 21 to the wheel cylinder 42FR by the holding valve 61FR that has been closed is upstream. Transmission to the main flow path 52 on the side is prohibited (blocked). The left front wheel cylinder 42FL is connected to the pressurizing chamber 21b1 of the master cylinder 21 via the master cut valve 64, the master pressure passage 54, the master pressure pipe 12b, the pressure increasing mechanism 80, the pilot passage 16 and the master pressure pipe 12a. The fluid pressure is communicated with the master cylinder pressure Pmc_FL (or the servo pressure generated by the operation of the pressure increasing mechanism 80). That is, in this situation, the hydraulic fluid (in other words, master cylinder pressure Pmc_FL) transmitted directly from the pressurizing chamber 21b1 of the master cylinder 21 to the wheel cylinder 42FL by the holding valve 61FL that has been closed is upstream. Transmission to the main flow path 52 on the side is prohibited (blocked).

  As described above, when the possibility of liquid leakage is detected in the brake device of the vehicle, the holding valves 61FR and 61FL on the left and right front wheels are closed (in a shut-off state), that is, between the wheel cylinders 42FR and 42FL and the main flow path 52. Communication is interrupted. For this reason, the communication between the wheel cylinder 42FR for the left and right front wheels and the wheel cylinder 42FL via the main flow path 52 is blocked, and the wheel cylinders 42FR and 42FL for the left and right front wheels and the wheel cylinder 42RR for the left and right rear wheels via the main flow path 52. , 42RL is disconnected. Therefore, when the possibility of liquid leakage is detected in the vehicle brake device, the wheel cylinders 42 of the front wheel and the rear wheel are shut off from each other and the wheel cylinders 42 of the left front wheel and the right front wheel are shut off from each other on the front wheel side. Thus, the three brake systems of the left front wheel, the right front wheel, and the left and right rear wheels are independent of each other. As a result, even if liquid leakage actually occurs in any of these three brake systems, the other brake systems are not affected.

  By the way, in the vehicle brake device according to the present embodiment, the brake ECU 100 is based on the rotation state as the state of the wheel to which the braking force is applied, and the behavior of the vehicle at the time of braking is unstable, When it is necessary to perform known anti-skid control (anti-lock control) that suppresses excessive slip in the direction, the solenoids of the holding valve 61 and the pressure reducing valve 62 according to the anti-skid control (anti-lock control) The holding valve 61 and the pressure reducing valve 62 are opened or closed. That is, the brake ECU 100 adjusts the holding valve in accordance with the change required for the wheel cylinder pressure Pwc of the wheel cylinder 42 by the anti-skid control (anti-lock control), specifically, the pressure increase, pressure holding, and pressure reduction of the wheel cylinder pressure Pwc. 61 and the pressure reducing valve 62 are controlled to be opened or closed. This will be specifically described below.

  The brake ECU 100 in the present embodiment inputs the wheel speed Vxi (i = FR, FL, RR, RL) of each wheel detected by the wheel speed sensor 106. Then, the brake ECU 100, for example, among the acquired wheel speeds Vxi (i = FR, FL, RR, RL), at least three wheel speeds Vxi (i) excluding the right front wheel provided with the normally closed holding valve 61FR. = FL, RR, RL) is used to estimate the estimated vehicle speed Vb, and the difference between the estimated vehicle speed Vb and the three wheel speeds Vxi excluding the right front wheel (i = FL, RR, RL) The slip ratio Si (i = FL, RR, RL) is calculated as a slip state quantity representing the slip state in the direction. Here, for the calculation of the estimated vehicle speed Vb and the slip ratio Si (i = FL, RR, RL), a well-known calculation method that has been widely used can be adopted. deep.

  Regarding the estimated vehicle speed Vb, out of the three wheel speeds Vxi (i = FL, RR, RL) excluding the right front wheel, the brake ECU 100 first sets a value that is considered to be the closest to the actual vehicle speed as the estimated vehicle speed Vxb. select. Next, the brake ECU 100 suppresses the estimated vehicle body speed Vbn1 obtained by subtracting the positive constant α1 for suppressing the increase rate of the estimated vehicle body speed from the previously calculated vehicle body estimated speed Vbf and the decrease rate of the estimated vehicle body speed. The estimated vehicle speed Vbn2 is calculated by adding a positive constant α2 for the purpose. Then, the brake ECU 100 estimates (determines) an intermediate value among the selected vehicle speed Vxb, the calculated estimated vehicle speed Vbn1, and the calculated estimated vehicle speed Vbn2 as the current estimated vehicle speed Vb.

  For the slip ratio Si (i = FL, RR, RL) of the three wheels excluding the right front wheel, the brake ECU 100 determines the wheel speed Vxi (i = FL, RR, 3) of the three wheels from the estimated (determined) estimated vehicle body speed Vb. RL) respectively. Then, the brake ECU 100 divides the calculated value by the estimated vehicle speed Vb to estimate and calculate the slip ratio Si (i = FL, RR, RL) of each of the three wheels except the right front wheel. . In the following description, the slip ratio Si of three wheels (i = FL, RR, RL) is also simply referred to as a wheel slip ratio S for easy understanding.

  When the calculated slip rate S is equal to or greater than the predetermined slip rate Ss, or when the difference value of the calculated slip rate S between the wheels is equal to or greater than the predetermined value, the brake ECU 100 slips in the longitudinal direction of the wheel. It is determined that the anti-skid control (anti-lock control) needs to be performed because the vehicle behavior is excessive and the vehicle behavior is unstable. On the other hand, when the calculated slip ratio S is less than the predetermined slip ratio Ss, or when the difference value of the calculated slip ratio S between the wheels is less than the predetermined value, the brake ECU 100 has an unstable vehicle behavior. Therefore, it is determined that it is not necessary to perform anti-skid control (anti-lock control).

  By the way, in anti-skid control (anti-lock control), for example, the wheel cylinder pressure Pwc is increased below the wheel cylinder pressure Pwc of the wheel cylinder 42 corresponding to the braking force at which the wheel slip rate S becomes a predetermined slip rate Ss. The pressure is increased by pressure control, the pressure is reduced by pressure reduction control, or the pressure is maintained by pressure holding control. By carrying out such anti-skid control (anti-lock control), in order to stabilize the behavior of the unstable vehicle or prevent the vehicle behavior from becoming more unstable, the holding valve 61 is closed. It is necessary to reliably shift from the valve state to the valve open state. In this case, since the normally open holding valves 61FL and 61RR are likely to be in the open state by the biasing force of the spring, the wheel cylinder pressure Pwc can be controlled according to the anti-skid control (anti-lock control). However, the normally closed holding valves 61FR and 61RL, particularly the holding valve 61FR on the front wheel side, which is important for stabilizing the behavior of the vehicle during braking, must be shifted from the closed state to the opened state by energizing the solenoid. There is. In this case, for example, the solenoid is operated against the sticking of the solenoid pin, which is likely to occur when the valve closed state is maintained for a long period of time, and the holding valve 61FR is reliably shifted from the valve closed state to the valve open state. Therefore, it is necessary to control the wheel cylinder pressure Pwc according to the anti-skid control (anti-lock control).

  Here, the brake ECU 100 acquires the current flowing through the holding valve 61FR via the current detection circuit 100a1 provided in the electromagnetic valve drive circuit 100a. Thereby, the brake ECU 100 determines whether or not the normally closed holding valve 61FR is shifted from the closed state to the open state as the solenoid is energized by monitoring (monitoring) the acquired current. be able to. Hereinafter, monitoring the current acquired by the brake ECU 100 is referred to as “current monitoring”.

  Specifically, when the current monitor is normal, as shown in FIG. 5, the brake ECU 100 follows the well-known PWM (Pulse Width Modulation) control, for example, via the electromagnetic valve drive circuit 100a, and holds the holding valve 61FR. Supply current to the solenoid. At this time, the brake ECU 100 intermittently supplies a valve opening current, which is a current for shifting the holding valve 61FR from the valve closing state to the valve opening state, to the solenoid at a predetermined interval by feedforward. As a result, each time the valve opening current is intermittently supplied, the holding valve 61FR shifts to the valve opening state when it is in the valve closing state, and reliably maintains the valve opening state when it is already in the valve opening state. Further, the brake ECU 100 is a current for maintaining the holding valve 61FR that has transitioned from the closed state to the open state, and continuously supplies a maintenance current smaller than the open current to the solenoid by feedback. . As a result, the holding valve 61FR maintains the valve open state if the maintenance current is continuously supplied.

  Therefore, when the current monitor is normal, the normally closed holding valve 61FR is shifted from the closed state to the opened state in accordance with the valve opening control by the brake ECU 100 as shown in FIG. Therefore, according to anti-skid control (anti-lock control), for example, when the control pressure Px in the main flow path 52 is increased using the linear control valve 65, the increased control pressure Px passes through the holding valve 61FR. The wheel cylinder pressure Pwc in the wheel cylinder 42FR can be appropriately increased by being transmitted to the wheel cylinder 42FR.

  If the normally closed holding valve 61FR is shifted to the open state, the control pressure Px in the main flow path 52 is kept constant using the linear control valve 65 in accordance with anti-skid control (anti-lock control). Then, the held control pressure Px is transmitted to the wheel cylinder 42FR via the holding valve 61FR, and the wheel cylinder pressure Pwc in the wheel cylinder 42FR can be appropriately held. Further, if the normally closed holding valve 61FR is shifted to the open state, the control pressure Px in the main flow path 52 is reduced using the linear control valve 65 in accordance with the anti-skid control (anti-lock control). The hydraulic pressure is transmitted from the wheel cylinder 42FR to the main flow path 52 through the holding valve 61FR up to the reduced control pressure Px, and the wheel cylinder pressure Pwc in the wheel cylinder 42FR can be appropriately reduced. Here, during the execution of the anti-skid control (anti-lock control), the holding valve 61FR is maintained in the open state, so that the upstream control pressure Px is transmitted to the wheel cylinder pressure Pwc in the downstream wheel cylinder 42FR. The control pressure Px and the wheel cylinder pressure Pwc are substantially equal, although it is slightly delayed by the time required to do this.

  On the other hand, when the current monitor is abnormal, the brake ECU 100 ensures that the holding valve 61FR is reliably closed from the closed state by energizing the solenoid, that is, the valve opening current supplied by feedforward and the maintenance current supplied by feedback. It becomes impossible to determine whether or not the valve is open. Therefore, when the current monitor is abnormal, the brake ECU 100 maintains the current to shift the holding valve 61FR from the closed state to the open state according to the duty waveform when the current monitor is abnormal in the PWM control, as shown in FIG. A compensation current set larger than the current is intermittently supplied to the solenoid at a predetermined interval by feedforward. In this case, it is more preferable that the compensation current is set to be larger than the valve opening current for a predetermined time. Here, the predetermined time is variable according to a function using, for example, the temperature of the solenoid (coil) built in the holding valve 61FR or a physical quantity (yaw rate γ, acceleration G, etc.) detected by the behavior change detection sensor 107. It can be set as time, or can be set as a predetermined time set in advance.

  When the current monitor is abnormal, the brake ECU 100 does not supply a maintenance current by feedback to the solenoid of the holding valve 61FR as shown in FIG. As a result, the holding valve 61FR surely shifts from the closed state to the open state every time the compensation current is supplied, and when the supply of the compensation current is interrupted, the holding valve 61FR is opened by the biasing force of the spring. To the closed valve state.

  Therefore, even when the current monitor is abnormal, as shown in FIG. 6, the normally closed holding valve 61FR is intermittently shifted from the closed state to the opened state in accordance with the valve opening control by the brake ECU 100. . Therefore, for example, when the control pressure Px in the main flow path 52 is increased using the linear control valve 65 according to the anti-skid control (anti-lock control), the increased control pressure Px is intermittently opened. The wheel cylinder pressure Pwc in the wheel cylinder 42FR can be increased stepwise by being transmitted to the wheel cylinder 42FR via the holding valve 61FR. Further, when the control pressure Px in the main flow path 52 is kept constant by using the linear control valve 65 in accordance with the anti-skid control (anti-lock control), the holding valve in which the maintained control pressure Px is opened. The wheel cylinder pressure Pwc in the wheel cylinder 42FR can be appropriately maintained by being transmitted to the wheel cylinder 42FR via 61FR and closing the holding valve 61FR. Further, when the control pressure Px in the main flow path 52 is reduced using the linear control valve 65 in accordance with the anti-skid control (anti-lock control), the wheel cylinder 42FR moves from the wheel cylinder 42FR to the main flow path 52 via the opened holding valve 61FR. The hydraulic pressure is transmitted, and the wheel cylinder pressure Pwc in the wheel cylinder 42FR can be reduced stepwise. As a result, the brake ECU 100 reliably and quickly opens the holding valve 61FR from the closed state without confirming whether or not the normally closed holding valve 61FR is operating, regardless of the current monitor. The state can be changed.

  As can be understood from the above description, according to the above embodiment, in a situation where an abnormality has occurred in the current monitor, the behavior of the vehicle becomes unstable and it is necessary to perform anti-skid control (anti-lock control). In this case, a compensation current that is guaranteed to shift to the valve open state can be supplied to the normally closed holding valve 61FR. As a result, the normally closed holding valve 61FR provided on the front wheel side can be reliably shifted from the closed state to the open state, and the wheel cylinder pressure Pwc in the wheel cylinder 42FR is appropriately increased, held and reduced. can do. Therefore, it is possible to stabilize the behavior of the vehicle or to effectively prevent the behavior of the vehicle from becoming more unstable.

<First Modification>
In the above embodiment, the brake ECU 100 supplies the compensation current to the normally closed holding valve 61FR when an abnormality occurs in the current monitor under the situation where the behavior of the vehicle is unstable. Carried out.

  In this case, the brake ECU 100 supplies the compensation current to the normally closed holding valve 61FR at least under the condition that the behavior of the vehicle is unstable regardless of whether the current monitor is normal or abnormal. It is also possible to carry out. The brake ECU 100 determines whether an abnormality (specifically, sticking or the like) has occurred in the operation of the normally closed holding valve 61FR based on, for example, a current monitor, but the behavior of the vehicle is unstable. When anti-skid control (anti-lock control) or vehicle stability control is performed, compensation current is supplied even if there is no abnormality in the operation of the normally closed holding valve 61FR. It is also possible to implement. Therefore, according to the first modification, the normally closed holding valve 61FR can always be shifted from the closed state to the open state under the situation where the behavior of the vehicle is unstable. An effect equivalent to that of the embodiment can be expected.

<Second Modification>
In the embodiment and the first modification, the brake ECU 100 inputs the wheel speed Vxi (i = FR, FL, RR, RL) representing the rotation state of the wheel acquired from the wheel speed sensor 106 as the state of the wheel. Was carried out as follows. The brake ECU 100 then sets the three wheel speeds Vxi (i = FL) of the input wheel speed Vxi (i = FR, FL, RR, RL) excluding the right front wheel provided with the normally closed holding valve 61FR. , RR, RL) is used to calculate the slip ratio Si (i = FL, RR, RL), and to determine whether the behavior of the vehicle is unstable. In this case, it is also possible to directly input a change in the behavior of the vehicle caused by a change in the state of the wheel, more specifically, the rotation state of the wheel.

  That is, in this case, the brake ECU 100 inputs the yaw rate γ and the acceleration G representing the behavior change of the vehicle from the behavior change amount detection sensor 107. Then, the brake ECU 100 detects the change in the yaw of the vehicle using the input yaw rate γ, and also detects the change in the vehicle by detecting the change in acceleration using the acceleration G. By comparing with the yaw rate γo or the predetermined acceleration Go, it can be determined whether or not the behavior of the vehicle is unstable. In this case, the brake ECU 100 determines a braking force to be applied to each wheel according to, for example, well-known vehicle stability control, and determines a wheel cylinder pressure Pwc for realizing this braking force.

  At this time, the brake ECU 100 ensures that the holding valve 61FR is supplied by supplying the valve opening current and the maintenance current to the normally closed holding valve 61FR when the current monitor is normal, for example, as in the above-described embodiment. It is possible to control the wheel cylinder pressure Pwc by shifting to the valve open state and transmitting the adjusted control pressure Px to the wheel cylinder 42FR. As described above, the brake ECU 100 intermittently and reliably shifts the holding valve 61FR to the open state by supplying only the compensation current to the normally closed holding valve 61FR when an abnormality occurs in the current monitor. Then, the adjusted control pressure Px can be transmitted to the wheel cylinder 42FR to control the wheel cylinder pressure Pwc. Therefore, also in this second modification, the same effect as in the above embodiment can be obtained.

<Third Modification>
In the embodiment and the first and second modified examples, the brake ECU 100 is implemented so as to intermittently supply the compensation current according to the duty waveform in the PWM control at least in a situation where the behavior of the vehicle is unstable. . In other words, in the above embodiment and the first and second modifications, the brake ECU 100 supplies a compensation current to shift the normally closed holding valve 61FR to the open state regardless of the change in the upstream control pressure Px. Was carried out.

  On the other hand, the value of the target hydraulic pressure of the control pressure Px determined corresponding to the magnitude of the braking force applied to the wheel according to the brake operation by the driver, or the control detected by the control pressure sensor 104 The detected value of the pressure Px is compared with a predetermined value Po set in advance, and as shown in FIG. 6, every time the value of the target hydraulic pressure of the control pressure Px or the detected value of the control pressure Px changes by more than the predetermined value Po. In addition, the brake ECU 100 may supply the compensation current to the normally closed holding valve 61FR. According to the third modification, it is possible to supply the compensation current in accordance with the change in the upstream control pressure Px and shift the normally closed holding valve 61FR to the valve open state.

  For this reason, for example, whenever the driver releases the brake operation on the brake pedal 10, the value of the target hydraulic pressure of the control pressure Px or the detected value of the control pressure Px decreases by a predetermined value Po or more, the brake ECU 100 A compensation current can be supplied to the normally closed holding valve 16FR. Thereby, the normally closed holding valve 16FR can be reliably shifted from the closed state to the open state, and the wheel cylinder pressure Pwc of the wheel cylinder 42FR is reliably reduced via the main flow path 52 and the pressure reducing linear control valve 65B. Can be made. Therefore, the driver does not feel a feeling of being caught when the vehicle is braked, and an extremely good brake feeling can be obtained.

  In carrying out the present invention, the present invention is not limited to the above-described embodiments and modifications, and various modifications can be made without departing from the object of the present invention.

  For example, in the above-described embodiment and each modified example, the compensation current is supplied to the normally closed holding valve 61FR provided on the front wheel side of the vehicle so as to surely shift from the closed state to the open state. did. In this case, it goes without saying that the compensation current can be similarly supplied to the normally closed holding valve 61RL provided on the rear wheel side of the vehicle so as to surely shift from the closed state to the open state. Yes.

  Moreover, in the said embodiment and each modification, it implemented so that a compensation current might be supplied with respect to the normally-closed holding valve 61FR, For example, from the valve-open state with respect to normally-opened holding valves 61FL and 61RR, for example. It is also possible to supply a compensation current that guarantees the transition to the valve-closed state so as to surely shift from the valve-open state to the valve-closed state. Further, in the above embodiment and each modified example, the compensation current is supplied to the normally closed holding valve 61FR. For example, the pressure reducing valve is an electromagnetic on-off valve configured similarly to the holding valve 61. It is also possible to supply a compensation current to 62.

  In these cases, for example, the holding valve 61 is opened and the pressure reducing valve 62 is maintained closed according to the pressure increase control in the anti-skid control (anti-lock control) or the vehicle stability control. When the holding valve 61 is closed according to the pressure reducing control and the pressure reducing valve 62 is opened, the holding valve 61 is closed and the pressure reducing valve 62 is closed according to the pressure holding control. The case where it is done can be realized reliably. As a result, for example, the holding valve 61 and the pressure reducing valve 62 can be reliably shifted to an open / closed state with anti-skid control (anti-lock control) or vehicle stability control, and the wheel cylinder pressure of the connected wheel cylinder 42 is Pwc can be controlled appropriately.

  Moreover, in the said embodiment and each modification, it implemented so that the servo pressure output from the pressure increase mechanism 80 might be directly transmitted to the wheel cylinder 42FL. In this case, the servo pressure can be transmitted from the pressure increasing mechanism 80 to the master cylinder 21. In this case, specifically, a hydro booster is provided in the master cylinder 21 and servo pressure is supplied from the pressure increasing mechanism 80 to the hydro booster. As a result, it is possible to transmit the hydraulic pressure corresponding to the servo pressure to the wheel cylinder 42FL, for example, via the master cylinder 21, and the same effects as those of the above-described embodiment and each modification can be expected.

  Moreover, in the said embodiment and each modification, the brake device of the vehicle provided with the pressure increase linear control valve 65A and the pressure reduction linear control valve 65B as the linear control valve 65 was employ | adopted and implemented. In this case, the pressure-reducing linear control valve 65B may be omitted, and a vehicle brake device including only the pressure-increasing linear control valve 65A may be employed. Moreover, in the said embodiment and each modification, the brake device of the vehicle provided with the pressure increase mechanism 80 and the pressure increase mechanism cut valve 90 was employ | adopted and implemented. In this case, it is also possible to employ a vehicle brake device that does not include the pressure increase mechanism 80 and the pressure increase mechanism cut valve 90. Even in these cases, the same effects as those of the above-described embodiment and each modification can be obtained.

  Furthermore, in the above-described embodiment and each modified example, when the above-described initial check is performed, there is a possibility that an operating sound is generated due to the switching operation of each electromagnetic on-off valve. Therefore, for example, when the vehicle is HV or PHV, an initial check is performed when the rotational speed of the internal combustion engine is equal to or higher than a predetermined rotational speed, or when the vehicle is EV, the volume of the audio device The initial check can be executed when is at a predetermined volume or higher. As a result, the operation sound generated by the initial check can be mixed into the sound emitted from the internal combustion engine or the sound emitted from the audio device, making it difficult for the driver or passenger to perceive the operation sound. Can do.

  DESCRIPTION OF SYMBOLS 10 ... Brake pedal, 20 ... Master cylinder unit, 30 ... Power hydraulic pressure generator, 40 ... Brake unit, 50 ... Hydraulic pressure control valve apparatus, 51 ... Individual flow path, 52 ... Main flow path, 56 ... Individual flow path for pressure reduction , 61FR, 61FL, 61RR, 61RL ... holding valve, 62FR, 62FL, 62RR, 62RL ... pressure reducing valve, 65 ... linear control valve, 100 ... brake ECU, 100a ... solenoid valve drive circuit, 100a1 ... current detection circuit, 104 ... control Pressure sensor 106 ... Wheel speed sensor 107 ... Behavior change amount detection sensor

Claims (12)

Comprising a master cylinder that generates hydraulic pressure in response to the operation of a brake pedal by a driver, a powered hydraulic pressure source that generates hydraulic pressure by driving a pressurizing means, and a plurality of electromagnetic valves controlled by electrical signals, A valve mechanism to which a hydraulic pressure output from the master cylinder or the power hydraulic pressure source is transmitted, and a wheel to which the hydraulic pressure output from the master cylinder or the power hydraulic pressure source is transmitted via the valve mechanism A wheel cylinder for applying a braking force to the motor, a drive circuit for supplying a current to each of the solenoid valves constituting the valve mechanism to drive the solenoid valves, and an operation of the valve mechanism via the drive circuit In a vehicle brake device comprising a control means for controlling
The valve mechanism is
Among the holding valves that are electromagnetic on-off valves that are provided for each wheel and realize communication or blocking between the upstream side to which the hydraulic pressure from the power hydraulic pressure source is transmitted and the downstream side to which the wheel cylinder is connected, Has at least one normally closed holding valve;
The control means includes
Determining whether or not the behavior of the vehicle is unstable based on the situation of the wheel to which braking force is applied by the wheel cylinder not connected to the normally closed holding valve;
By the determination, when the vehicle behavior is unstable, the compensation current is increased than the current required when maintaining the open state of the holding valve normally closed, through the drive circuit The vehicle brake device is supplied to the normally closed holding valve. The vehicle brake device according to claim 1,
The current supplied from the drive circuit to the normally closed holding valve is:
An opening current that is intermittently supplied by feedforward in order to shift the normally closed holding valve from a closed state to an opened state, and the normally closed holding valve that is smaller than the opening current is opened. A maintenance current continuously supplied by feedback to maintain
The control means includes
As a result of the determination, when the vehicle behavior is unstable, a compensation current obtained by increasing the valve opening current for a predetermined time without supplying the maintenance current is supplied via the drive circuit to the normally closed state. A brake device for a vehicle, wherein the brake device is supplied to a holding valve. The vehicle brake device according to claim 2,
The compensation current that the control means supplies to the normally closed holding valve via the drive circuit is:
A brake device for a vehicle, which is supplied according to duty control. In the brake device of the vehicle according to any one of claims 1 to 3,
The control means includes
It is determined whether or not the behavior of the vehicle is unstable based on a rotation state of a wheel to which a braking force is applied by the wheel cylinder not connected to the normally closed holding valve. Brake device. The vehicle brake device according to any one of claims 1 to 4, wherein:
The control means includes
Whether or not the vehicle behavior is unstable based on a behavior change that occurs in the vehicle due to a rotational state of a wheel to which braking force is applied by the wheel cylinder that is not connected to the normally closed holding valve A braking device for a vehicle, characterized in that The vehicle brake device according to claim 5,
The behavior change occurring in the vehicle is at least
A change in the yaw generated in the vehicle due to a difference in the rotation state of the wheel to which the braking force is applied, or an acceleration change generated in the vehicle due to the difference in the rotation state of the wheel to which the braking force is applied. Brake device. The vehicle brake device according to any one of claims 4 to 6,
The rotation state of the wheel is at least:
A brake device for a vehicle, which is a slip state amount representing a slip state of a wheel or a difference between the slip state amounts for each wheel. The vehicle brake device according to any one of claims 1 to 7,
The drive circuit is
Detecting the current flowing through the normally closed holding valve and outputting it to the control means;
The control means includes
Using the detected current output from the drive circuit, it is determined whether an abnormality has occurred in the opening and closing operation of the normally closed holding valve,
Even when the abnormality does not occur in the opening / closing operation of the normally closed holding valve by the determination, when the behavior of the vehicle is unstable, the compensation current is passed through the drive circuit, A brake device for a vehicle, wherein the brake device is supplied to the normally closed holding valve. The vehicle brake device according to any one of claims 1 to 8,
The control means includes
At least the value of the target hydraulic pressure determined corresponding to the magnitude of the braking force applied to the wheel and transmitted from the power hydraulic pressure source to the upstream side of the normally closed holding valve, or the power formula Compare the detected value of the hydraulic pressure transmitted from the hydraulic pressure source to the upstream side of the normally closed holding valve and a predetermined value set in advance,
Each time the target hydraulic pressure value or the detected value changes by more than the predetermined value, the compensation current is supplied to the normally closed holding valve via the drive circuit. . In the vehicle brake device according to claim 2 or 3,
The compensation current is
A variable time determined according to a function using at least one of the temperature of the built-in coil used for opening and closing the normally closed holding valve and a physical quantity representing the behavior of the vehicle, or a predetermined constant time A braking device for a vehicle, which is a current obtained by increasing the valve opening current only. The vehicle brake device according to any one of claims 1 to 10,
A booster connected to the master cylinder and the power hydraulic pressure source to generate a hydraulic pressure having a predetermined ratio with respect to the hydraulic pressure from the master cylinder using the hydraulic pressure from the power hydraulic pressure source. A vehicle brake device comprising a mechanism. The vehicle brake device according to claim 11,
The pressure increasing mechanism is
A brake device for a vehicle, which is mechanically operated by a hydraulic pressure output from the master cylinder in accordance with an operation of the brake pedal by the driver.

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