JP2001191909A - Automatic brake device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic brake device capable of freely controlling desired brake force by a simple and low-cost controller controlling only a pump housed in a wheel lock prevention device when generating brake hydraulic pressure without driver's operation. SOLUTION: This brake device is provided with an auxiliary hydraulic pressure source, i.e., the pump b housed in the wheel lock prevention device e disposed between a master cylinder (a) and a wheel cylinder c, sucking a brake liquid from a reservoir f, and changing a pressure of the brake liquid into a discharge pressure according to a drive control command from the brake controller d; a normally open first changeover valve g disposed in a communication passage between the master cylinder (a) and the wheel lock prevention device e; a normally closed second changeover valve h disposed in a communication passage between the master cylinder (a) and the suction side of the pump b; a check valve i disposed between the discharge side of the pump b and the first changeover valve g; and a flow control valve j disposed between the master cylinder (a) and the first changeover valve g, restricting a flow rate to the master cylinder (a) from the first changeover valve g in a communication state according to the discharge pressure from the driven and controlled pump b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of an automatic brake device for automatically generating a braking force without operation of a driver in a vehicle-to-vehicle distance maintaining control or the like.

[0002]

2. Description of the Related Art Conventionally, a vehicle behavior control device (so-called VD) for preventing sideslip of a vehicle by brake control of each wheel individually.
Examples of the automatic braking device using C) include, for example, JP-A-10-100876 and JP-A-10-2787.
No. 56 is known.

In the prior art described in these publications, a pressurized fluid generated by an auxiliary hydraulic pressure source during automatic braking is
It is supplied to the wheel cylinder to generate braking force.
To adjust the braking force, the pressure of the pressurized fluid from the auxiliary hydraulic pressure source is detected, and if the pressure is lower than the target braking force, the rotation speed of the pump motor is increased to increase the pressure from the auxiliary hydraulic pressure source. generate. When the braking force is excessive, the solenoid valve is controlled and the pressure is released for adjustment.

[0004]

However, in the above-mentioned conventional automatic brake device, the pressure on the pressure increasing side is controlled by motor control, and the pressure on the pressure decreasing side is controlled by solenoid valve control. In order to control the opening of the motor smoothly and with high accuracy, a high-precision solenoid valve is required, and multiple controls of motor control and solenoid valve control are required, and the control device is complicated and expensive. There was a problem that would be.

[0005] The problem to be solved by the present invention is to generate the brake fluid pressure without depending on the driver's operation.
An object of the present invention is to provide an automatic brake device that can freely control a desired braking force by a simple and inexpensive control device that controls only a pump included in a wheel lock prevention device.

[0006]

According to the first aspect of the present invention, there is provided a master cylinder for generating a master cylinder pressure corresponding to a driver's operation force, and an auxiliary for generating a hydraulic pressure separately from the master cylinder pressure. A hydraulic pressure source and a wheel cylinder that applies a braking force to the wheels according to the supplied brake hydraulic pressure. The hydraulic pressure from the auxiliary hydraulic pressure source is adjusted by a control command from the brake controller to the wheel cylinder. In the automatic brake device that automatically generates a braking force without depending on a driver's braking operation by supplying the auxiliary hydraulic pressure source, a wheel lock prevention device disposed between a master cylinder and a wheel cylinder. A pump that sucks the brake fluid from the reservoir tank and sets the discharge pressure according to the drive control command from the brake controller. Disposed in the communication passage between the Sunda and the wheel lock preventive device, normally in communication with the switch in a non-communicating a command from the brake controller 1
A switching valve, which is disposed in a communication path between the master cylinder and the suction side of the pump, is normally in a non-communication state, and is switched to a communication state in response to a command from a brake controller.
A switching valve, a check valve disposed between the discharge side of the pump and the first switching valve, and allowing communication only in the direction of the first switching valve; and a check valve between the master cylinder and the first switching valve. And a flow control valve for limiting the flow from the first switching valve in communication to the master cylinder in accordance with the discharge pressure from the pump whose drive is controlled.

According to a second aspect of the present invention, in the automatic brake device according to the first aspect, the flow control valve is configured such that a discharge pressure from a pump is set as an operation signal pressure, and the flow area increases as the discharge pressure increases. The valve is characterized in that it is a valve that restricts the flow rate by a variable throttle action that increases the throttle amount.

According to a third aspect of the present invention, in the automatic brake device according to the first or second aspect, when the automatic brake command is input to the brake controller, the first switching valve is set to non-communication. A command to connect the second switching valve is output, a target hydraulic pressure is calculated in response to the target deceleration instruction, and an operation control command is output to the pump in accordance with a gradient at which the target hydraulic pressure is reached. When the wheel cylinder pressure is held by outputting a stop command to the pump while the first switching valve is kept in non-communication, and the increased wheel cylinder pressure is decreased, the first switching valve is controlled. By outputting a communication command and outputting an operation control command to the pump in accordance with the pressure reduction gradient,
A means for reducing the wheel cylinder pressure by means of a balance between the pressurization of the wheel cylinder pressure by the pump discharge pressure and the release of the wheel cylinder pressure through a flow control valve whose flow path cross-sectional area is adjusted. I do.

According to a fourth aspect of the present invention, in the automatic brake device according to the first aspect, when the brake controller inputs a command to control the braking force of each wheel when the brake is not operated, A command to make the first switching valve non-communicating and a command to operate the second switching valve and a command to operate the pump are output, and the pressure-increasing valve and the pressure-reducing valve included in the wheel lock prevention device are increased / retained for each wheel. / A means for outputting a command for controlling the pressure reduction.

According to a fifth aspect of the present invention, in the automatic brake device according to the first aspect, a booster for detecting an assist limit of a braking operation by a booster provided between a brake pedal and a master cylinder. A boost limit detecting means and a master cylinder pressure sensor for detecting a master cylinder pressure are provided, and when the boost controller detects a boost boost limit including a booster failure, a target boost amount is determined based on the master cylinder pressure detection value. Means for calculating, outputting a command to make the first switching valve non-communicating and making the second switching valve open, and outputting to the pump an operation command to obtain a target hydraulic pressure according to the target assisting amount. .

[0011]

According to the first aspect of the present invention, when a braking force is automatically generated without a driver's braking operation, a braking command is issued by a control command from a brake controller. 1 Switch the switching valve to the non-communication side, and
When the switching valve is switched to the communication side and the pump included in the wheel lock prevention device is operated, the brake fluid sucked in from the reservoir tank via the second switching valve changes the discharge pressure according to the operation control command to the pump. This discharge pressure is supplied to the wheel cylinder to generate a braking force. At this time, the communication path between the master cylinder and the wheel cylinder is
Although the hydraulic pressure transmission is interrupted by the first switching valve, it is difficult to smoothly increase the pressure due to pulsation if the pressure is an intermittent compression type pump such as a plunger pump when the target hydraulic pressure value is low. Become. In this case, the first switching valve is set to communicate,
When the pressure is increased while partially releasing the pressure by the flow control valve, a smooth pressure increase is possible. Then, the wheel cylinder pressure is maintained by stopping the pump while keeping the first switching valve in the non-communication state. Further, when decreasing the increased wheel cylinder pressure, the first switching valve is set in communication with a control command from the brake controller, and when the pump is operated, the flow path cross-sectional area of the flow control valve is adjusted. Can be reduced by lowering the pump discharge pressure and reducing the throttle effect of the flow control valve, and if you want to reduce the pressure slowly, increase the pump discharge pressure and increase the flow control valve. By increasing the throttling effect and making the pressurization of the wheel cylinder substantially equal to the opening pressure via the flow control valve, fine pressure reduction control is possible. Therefore, when generating the brake fluid pressure without depending on the driver's operation, the braking force can be freely controlled by a simple and inexpensive brake controller that controls only the pump included in the wheel lock prevention device. .

In the invention according to claim 2 of the present invention, the flow control valve uses the discharge pressure from the pump as an operation signal pressure, and the higher the discharge pressure, the greater the amount of restriction in the flow path area. A valve that limits the flow rate is used. Therefore, by controlling the discharge pressure by controlling the rotation speed of the motor that drives the pump, it is possible to control the throttle amount of the flow area of the flow control valve.

According to the third aspect of the present invention, when an automatic brake command is input to the brake controller, a command is output to disconnect the first switching valve and communicate the second switching valve. The target hydraulic pressure is calculated in response to the target deceleration command, and the wheel cylinder pressure is increased by outputting an operation control command to the pump in accordance with the gradient reaching the target hydraulic pressure. Then, by outputting a stop command to the pump while the first switching valve is kept in non-communication, the wheel cylinder pressure is maintained. Further, when decreasing the increased wheel cylinder pressure, a command to connect the first switching valve is output, and by outputting an operation control command to the pump in accordance with the pressure reduction gradient, the wheel cylinder pressure due to the pump discharge pressure is output. The pressure of the wheel cylinder is controlled to be reduced by the balance between the pressurization of the wheel cylinder and the release of the wheel cylinder pressure via the flow control valve whose flow path cross-sectional area is adjusted. Therefore, at the time of automatic braking in which the brake fluid pressure is generated without the driver's operation, the switching control of the first switching valve and the second switching valve and the operation control of the pump included in the wheel lock prevention device are performed. As a result, desired pressure increasing characteristics and pressure reducing characteristics can be obtained.

According to a fourth aspect of the present invention, when the brake controller inputs a command for controlling the braking force of each wheel when the brake is not operated,
A command to make the first switching valve non-communicating and a communication to the second switching valve and a command to operate the pump are output, and a pressure increase / decrease valve included in the wheel lock prevention device is supplied to the pressure increasing / decreasing valve of each wheel. A command for controlling the holding / reducing pressure is output. Therefore,
The present invention can be used not only as an automatic brake device but also as a brake fluid pressure control actuator for a vehicle behavior control device (VDC) or a traction control device (TCS) that needs to control the braking force of each wheel when the brake is not operated.

According to a fifth aspect of the present invention, in the brake controller, boosting assistance including failure of the booster is provided by boosting assistance limit detecting means for detecting an assistance limit of a braking operation by the booster. When the limit is detected, the target assisting amount is calculated based on the master cylinder pressure detection value,
A command to make the first switching valve non-communicating and to make the second switching valve communicate is output, and an operation command of a pump for obtaining a target hydraulic pressure according to the target assisting amount is output. Therefore, when the assist of the booster reaches the limit for the braking operation including the failure of the booster at the time of the braking operation by the normal driver, the brake is generated by the pump instead of the braking by the master cylinder pressure. When the braking operation is performed beyond the assisting limit of the booster, a sudden change in the operating force can be prevented without a sudden increase in the braking operation force. ,
In the event of a booster failure due to a device failure, booster pressure source failure, or the like, the same braking force as when the booster is normal can be obtained and used as a fail-safe at the time of failure.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) Embodiment 1 is an automatic brake device corresponding to the first to fifth aspects of the present invention.

The configuration will be described. FIG. 1 is a conceptual diagram showing a main part of an automatic brake device according to a first embodiment, where a is a master cylinder, b is a pump (auxiliary hydraulic pressure source), c is a wheel cylinder, d is a brake controller, and e is wheel lock prevention. Device, f is the reservoir tank, g is the first switching valve, h
Is a second switching valve, i is a check valve, and j is a flow control valve. When the driver automatically generates a braking force without performing a braking operation such as depressing the brake pedal k, a signal from the brake controller d is issued. By the control command, the first switching valve g is switched to the non-communication side, the second switching valve h is switched to the communication side, and the operation of the pump b is controlled to perform the pressure increase control of the wheel cylinder pressure. The wheel cylinder pressure is held by stopping the pump b while the valve g is kept disconnected, and when the increased wheel cylinder pressure is reduced, the first switching valve g is controlled by a control command from the brake controller d. When the pump b is operated, the flow path cross-sectional area of the flow control valve j is adjusted.
The pressure reduction of the wheel cylinder pressure is performed according to a pressure reduction gradient determined by the discharge pressure from the cylinder.

FIG. 2 is an overall circuit diagram showing the automatic brake device according to the first embodiment, wherein 1 is a brake pedal, 2 is a vacuum booster, 3 is a master cylinder, 4 is a reservoir tank, 6
Is a hydraulic pressure adjusting actuator, 7RR, 7FL, 7FR, 7RL are wheel cylinders, 8 is a brake switch, 9 is a booster negative pressure sensor, 10 is a primary master cylinder pressure sensor, and 11 is a secondary master cylinder pressure sensor.

The negative pressure booster 2 has a negative pressure chamber communicating with an intake system of the engine (not shown), and uses a differential pressure between the atmospheric pressure and the intake negative pressure to apply a pedaling force to the brake pedal 1. Enhance.

The master cylinder 3 increases the pedal depression force applied to the brake pedal 1 by the negative pressure type booster 2, and generates a master cylinder pressure corresponding to the pedal depression force.

The hydraulic pressure adjusting actuator 6 comprises a master cylinder 3 and wheel cylinders 7RR, 7FL, 7FR, 7RL.
Automatic braking function that generates a braking force regardless of the driver's braking operation, a boost assist function that generates a braking force when the booster fails, a vehicle behavior control device (hereinafter, referred to as
VDC) and traction control device (hereinafter TCS)
VDC / TC that controls the braking force of each wheel
An actuator that exhibits the S function.

The wheel cylinders 7RR, 7FL, 7FR,
7RL is a braking means for applying a braking force to each wheel according to the wheel cylinder pressure supplied via the hydraulic pressure adjusting actuator 6, and a primary port of the master cylinder 3 is connected to the wheel cylinders 7RR and 7FL; Master cylinder 3 secondary port and wheel cylinder 7FR,
The X pipe is connected to 7RL.

Next, the specific structure of the hydraulic pressure adjusting actuator 6 will be described. MCS is a first switching valve, BCS
Is a second switching valve, OP is a pump, M is a pump motor, VO
V is a flow control valve, RV is a relief valve, CSB is a pressure increasing valve,
CSD is a pressure reducing valve, RSV is a reservoir, and CHV is a check valve. In addition, 15 is a primary wheel cylinder pressure sensor, and 16 is a secondary wheel cylinder pressure sensor.

Between the first switching valve MCS and the wheel cylinders 7RR, 7FL, 7FR, 7RL, pressure increase / hold / pressure reduction is individually performed for each wheel by a control command from the brake controller 12 shown in FIG. An ABS actuator (wheel lock prevention device) capable of performing control is provided. This individual pressure adjusting actuator includes a pressure-intensifying valve CSB and a pressure-reducing valve CSD provided for each wheel,
Reservoir RSV provided in each system and booster valve C
Check valve CHV and pump OP arranged in parallel with SB
And a pump motor M.

The pump OP is an auxiliary hydraulic pressure source which is included in the ABS actuator and sucks and pressurizes the brake fluid from the reservoir tank 4 via the master cylinder 3 and the second switching valve BCS, as shown in FIG. The pump rotation speed is controlled by a drive command from the brake controller 12 to the pump motor M.

The first switching valve MCS is a normally open type solenoid ON / OFF valve disposed in a communication path between a primary system and a secondary system for communicating the master cylinder 3 and the ABS actuator. As shown in the figure, the communication state is established, and the communication is switched to the non-communication state by a command from the brake controller 12 shown in FIG.

The second switching valve BCS is a normally-closed type solenoid ON / OFF valve disposed in a communication path between a primary system and a secondary system that communicates between the master cylinder 3 and the suction side of the pump OP. As shown in FIG. 2, it is in a non-communication state, and is switched to communication by a command from the brake controller 12 shown in FIG.

The discharge side of the pump OP and the first switching valve M
The check valve CHV, which is disposed between the check valve CH and the first switching valve MCS and allows communication only in the direction of the first switching valve MCS, corresponds to a check valve according to claim 1.

The flow control valve VOV is disposed between the master cylinder 3 and the first switching valve MCS, and is driven by a brake controller 12 shown in FIG.
A valve for restricting a flow rate from the first switching valve MCS in communication with the master cylinder 3 in accordance with a discharge pressure from the P. The discharge pressure from the pump OP is used as an operation signal pressure. The flow rate is limited by the variable throttling effect which increases the throttling amount of the area.

The relief valve RV is a valve that regulates the upper limit pressure of the discharge pressure from the pump OP.

Next, the flow control valve VOV will be described with reference to FIGS. 3 and 4. The flow control valve VOV includes a pump discharge pressure port 20a, a master cylinder pressure port 20b, a wheel cylinder pressure port 20c, and a drain port 29d.
A large diameter chamber 21 and a small diameter chamber 22 formed in communication with the spool housing 20, and a spool piston 23 slidably provided in the large diameter chamber 21 and the small diameter chamber 22. , The spool piston 2
And a spring 24 for urging the valve 3 to the right in the figure. The spool piston 23 has a piston portion 23 a having an outer diameter corresponding to the large-diameter chamber 21,
A rod portion 23b having an outer diameter corresponding to the small-diameter chamber 22,
The piston portion 23 is formed by a stopper portion 23c extending in a direction opposite to the rod portion 23b with respect to the piston portion 23a.
3a on the master cylinder pressure port 20b side and the stopper 2
Communication grooves 23d and 23e are formed at the end of 3c.

In operation, when the pump discharge pressure is maximum, as shown in FIG. 3, the cross-sectional area (flow area) of the wheel cylinder pressure port 20c is minimized by the piston portion 23a (orifice portion 25). When there is no pump discharge pressure,
As shown in FIG. 4, the piston section 23a and the wheel cylinder pressure port 20c do not overlap, and the flow passage area is not restricted at all. That is, the position of the spool piston 23 changes depending on the magnitude of the pump discharge pressure introduced into the small-diameter chamber 22, whereby the orifice effect can be variably controlled.

Next, the brake electronic control system will be described with reference to FIG. 5. The brake controller 12 includes a BLS signal from the brake switch 8, a booster negative pressure signal from the booster negative pressure sensor 9, and a primary master cylinder. A primary master cylinder pressure signal from the pressure sensor 10, a secondary master cylinder pressure signal from the secondary master cylinder pressure sensor 11, a primary wheel cylinder pressure signal from the primary wheel cylinder pressure sensor 15, and a signal from the secondary wheel cylinder pressure sensor 16. A secondary wheel cylinder pressure signal is input. Further, input information is provided from sensors 13 such as a wheel speed sensor, a liquid level sensor, a G sensor (at 4WD / VDC), a steering angle sensor (at VDC), and a yaw rate sensor (at VDC). Further, ECCS-ECU (Engine Centralized Electronic Control System), E-AT-ECU (Electronically Controlled Automatic Transmission Control System, which can be CVT-ECU (Electronically Controlled Continuously Variable Transmission Control System)), ETS / CSD
A controller 14 of another in-vehicle control system such as an ECU (electronic control system of front / rear wheel drive force distribution / left / right drive wheel differential limiting force) and an ACC-ECU (constant speed drive control system);
Exchange of information is performed. As a result of the arithmetic processing based on the input information, when the control of the brake fluid pressure is necessary, a control command is output to the solenoid valve and the pump motor of the fluid pressure adjusting unit 6.

The function and effect will be described. [Automatic Brake Operation] FIG. 6 is a flowchart showing the flow of the automatic braking operation. Each step will be described below.

When the ignition switch is turned on at step 50, a self-diagnosis operation is performed at step 51. When the self-diagnosis operation is completed, step 5
The program proceeds to step 2 where the brake controller 12 determines whether or not an automatic brake command has been input. This automatic brake command is input from a front-vehicle follow-up control device mounted on the vehicle.

When an automatic brake command is input,
The process proceeds from step 52 to step 53. In step 53, the target hydraulic pressure is calculated in response to the target deceleration instruction. The process proceeds to step 54, where it is determined whether or not the brake is depressed based on a switch signal from the brake switch 8, and If it is time, go to step 55,
The control is stopped, and the process returns to step 52.

If it is determined in step S54 that the brake is not being depressed, the process proceeds to step S56.
Then, an ON command for setting the first switching valve MCS to a non-communication state (closed) and an ON command for setting the second switching valve BCS to a communication state (open) are output. A command to operate the pump OP is output in accordance with. In the next step 58, if it is determined that the target hydraulic pressure is lower than the specified pressure while the pump OP is operating in accordance with the target hydraulic pressure, the process proceeds to step 59, in which an OFF command for making the first switching valve MCS communicate is provided. Is issued and the next step 60
Then, operate the pump OP to the specified pressure, and after reaching the specified pressure,
The operation of the pump OP is controlled at a rotation speed at which the relief by the flow control valve VOV and the pressurization by the pump OP are balanced. If it is determined in step 58 that the target hydraulic pressure is equal to or higher than the specified pressure, the process proceeds to step 60, where the first switching valve MCS is set in the communicating state,
The operation of the pump OP is controlled at a rotation speed at which the relief by the flow control valve VOV and the pressurization by the pump OP are balanced. In step 61, it is determined whether or not the target deceleration has been changed.
The rotation speed control of the pump OP is continued.

If it is determined in step 61 that the target deceleration has been changed, the routine proceeds to step 62, where the target hydraulic pressure is calculated in response to a new target deceleration instruction. In the next step 63,
It is determined whether or not the target hydraulic pressure is equal to or higher than the current pressure.
When YES (pressure increase) is determined in 3, the process proceeds to step 64, in which the rotational speed of the pump OP is increased to a specified pressure, and when it is determined NO (pressure decrease) in step 63, the rotational speed of the pump OP is decreased. It is relieved by the flow control valve VOV until it reaches the specified pressure. From step 64 or step 65, the process proceeds to step 66. In step 66, the pump OP is operated to the specified pressure, and after reaching the specified pressure, the flow control valve VO
The operation of the pump OP is controlled at a rotation speed at which the relief by V and the pressurization by the pump OP are balanced. Then, in step 67, it is determined whether or not the automatic brake command has been deleted, and the operation control of the pump OP is continued unless the automatic brake command is deleted.

If it is determined in step 67 that the automatic brake command has been erased, the process proceeds to step 68, in which an OFF command for setting the first switching valve MCS to a communication state (open) is output, and the second switching valve MCS is output. No communication with BCS (closed)
Is output, a command to stop the pump OP is output, and the process returns to step S52.

Therefore, when the braking force is automatically generated without depending on the driver's braking operation, the brake controller 12
, The first switching valve MCS is switched to the non-communication side, the second switching valve BCS is switched to the communication side, and the pump OP is operated. Pump OP is the master cylinder 3
, The brake fluid from the reservoir tank 4 is suctioned and pressurized. At this time, the brake controller 12 transmits the braking force to be generated to the wheel cylinders 7RR, 7FL, 7FR, 7FR.
The target hydraulic pressure is converted into the hydraulic pressure to be supplied to the RL, a target hydraulic pressure and a gradient reaching the target hydraulic pressure are set, and the rotation speed of the pump motor M for driving the pump OP is controlled so as to match the target hydraulic pressure characteristic. . At this time, when the target hydraulic pressure value is high or when the hydraulic pressure gradient is high, the first switching valve MCS remains closed. For this reason, the hydraulic pressure supplied by the pump OP is all supplied to the wheel cylinders 7RR, 7FL, 7FR, 7RL, and a quick braking force can be exerted. In addition, even when the target hydraulic pressure is low or the gradient is low, the first pressure increasing period during which the pressurizing efficiency of the pump OP is not good is the first switching valve MCS.
May be maintained in a closed state, and thereafter, may be shifted to an open state.
Further, in the case of a pressure increase when the target hydraulic pressure or the like is low, if the pump is an intermittent compression type pump OP such as a plunger pump, it is difficult to smoothly increase the pressure due to pulsation. In this case, if the first switching valve MCS is opened and the pressure is increased while the pressure is partially released by the flow control valve VOV, a smooth pressure increase is possible.

When the wheel cylinder pressure reaches the target pressure, the first switching valve MCS is kept closed, and the pump OP
Stops. In this state, the wheel cylinders 7RR, 7RR
Since the pressure supplied to FL, 7FR, 7RL is maintained as it is, the braking force is maintained at a constant state.

Thereafter, when the automatic braking becomes unnecessary,
By opening the first switching valve MCS, the wheel cylinder pressure passes through the master cylinder 3 and is solved in the reservoir tank 4, so that the braking force disappears. At this time, if a high pressure is supplied to the wheel cylinders 7RR, 7FL, 7FR, 7RL, a sudden release of the pressure may generate a fluid noise or the like. In this case, the opening / closing of the first switching valve MCS may be repeated in a short time to release the pressure stepwise.

The operation for reducing, rather than releasing, the wheel cylinder pressure maintained constant for some reason will be described. In this case, the pump OP is driven again, and the first switching valve MCS is opened. The pump OP sucks and pressurizes the liquid from the reservoir tank 4 through the master cylinder 3, and at this time, the hydraulic pressure generated by the driving of the pump OP is adjusted to the wheel cylinders 7RR, 7FL, 7F.
R, 7RL and also to a flow control valve VOV with a variable orifice valve structure. When the flow control valve VOV receives this pump discharge pressure, the built-in spool piston 23 causes the wheel cylinders 7RR, 7FL,
The opening area of the communication passage communicating between the 7FR, 7RL and the master cylinder 3 is reduced. For this reason, the wheel cylinder pressure is the first
Despite the switching valve MCS being in the open state, it is not rapidly opened to the master cylinder 3 side, that is, to the atmosphere, but is gradually opened from the oil passage narrowed by the flow control valve VOV, so that the braking force gradually decreases. I do. At this time, as the pressure generated by driving the pump OP increases, the flow control valve VO
V further narrows the oil passage, and if it is desired to rapidly reduce the pressure, the pump motor M that drives the pump OP
Can be dealt with by reducing the number of revolutions and reducing the throttle effect of the flow control valve VOV. If it is desired to decrease the pressure very slowly, the rotational speed of the pump motor M is increased, the pump OP pressurizes the wheel cylinders 7RR, 7FL, 7FR, 7RL and is released from the throttle of the flow control valve VOV. By making the pressures substantially equal, fine pressure adjustment is possible.

As a result, when the brake fluid pressure is generated without depending on the driver's operation, the desired braking force can be freely controlled by a simple and inexpensive control device that controls only the pump included in the wheel lock prevention device. Can be controlled.

[VDC Operation] FIG. 7 is a flowchart showing the flow of the VDC operation. Each step will be described below.

When the ignition switch is turned on at step 70, a self-diagnosis operation is performed at step 71. When the self-diagnosis operation is completed, step 7
The program proceeds to step 2 where it is determined in the brake controller 12 whether or not a VDC command has been input. This VDC command is
It is input from a vehicle behavior control device (vehicle dynamics controller: a system for reducing side slip of the vehicle by independent brake control of four wheels) mounted on the vehicle.

When the VDC command is input, the process proceeds from step 72 to step 73. In step 73, an ON command to make the first switching valve MCS non-communicating (closed) is output, and the second switching valve BCS is output to the second switching valve BCS. On the other hand, an ON command to make the communication state (open) is output, the process proceeds to the next step 74, a command to operate the pump OP at the set constant rotation speed is output, and further proceeds to step 75, where the ABS actuator is individually operated by the ABS actuator. The pressure increase / hold / pressure reduction of the wheels is controlled.

In step 76, it is determined whether the vehicle behavior has recovered. Until the vehicle behavior recovers, the individual brake control by the ABS actuators in steps 74 and 75 is performed. When the vehicle behavior recovers, Proceeding to step 77, an OFF command to output a communication state (open) to the first switching valve MCS is output, an OFF command to output a non-communicating state (closed) to the second switching valve BCS is output, and the pump OP is stopped. Is output, and the process returns to step 72.

In the flowchart of FIG. 7, a TCS operation command is used instead of the VDC operation command in step 72, and a drive slip convergence is used instead of the vehicle behavior recovery in step 76.
It can respond to brake control.

As a result, the braking force of each wheel is controlled individually, such as a vehicle behavior control device (VDC) for preventing the vehicle from skidding or a traction control device (TCS) for suppressing the driving wheel slip at the time of starting or accelerating. In a vehicle equipped with a control system to be used, a first switching valve MCS and a second switching valve B
By controlling the switching of the CS, the operation of the pump OP, and the control of each of the pressure increasing valve CSB and the pressure reducing valve CSD of the ABS actuator, not only the automatic brake control but also the control functions of the VDC and the TCS can be easily realized.

FIG. 8 is a flowchart showing a flow of the boosting assisting operation. Each step will be described below.

When the ignition switch is turned on in step 80, a self-diagnosis operation is performed in step 81. When the self-diagnosis operation is completed, step 8
2 and it is determined whether or not the brake is depressed based on a signal from the brake switch 8. When the brake is depressed, the process proceeds to step 83, where the boosting assist limit point is detected based on the detection value from the booster negative pressure sensor 9. In the next step 84, it is determined whether or not the boosting condition is insufficient at the booster negative pressure equal to or higher than the assisting limit point, that is, at the negative pressure level in the booster. The driver's target deceleration is estimated based on the sensor signals from the cylinder pressure sensors 10 and 11, and the target hydraulic pressure for obtaining the estimated target deceleration is calculated. In the next step 86, an ON command to output a non-communication state (closed) to the first switching valve MCS is output, and an ON command to output a communication state (open) to the second switching valve BCS is output. At 87, the operation of the pump OP is controlled in accordance with the target hydraulic pressure. In the next step 88, the pump OP is operated up to the target hydraulic pressure, and after reaching the target hydraulic pressure, the first switching valve MCS is opened, and the pump OP is driven at a rotational speed at which the relief by the flow control valve VOV and the pressurization by the pump OP are balanced.
Is controlled. In the next step 89, it is determined whether or not the master cylinder pressure has decreased. If it is determined that the master cylinder pressure has decreased, the routine proceeds to step 90, where the sensor signals from the master cylinder pressure sensors 10 and 11 are newly provided. , A driver target deceleration is estimated, and a target hydraulic pressure for obtaining the estimated target deceleration is calculated. In the next step 91, it is determined whether or not the target hydraulic pressure is equal to or higher than the assisting limit pressure. In the case of YES, the rotational speed of the pump OP is reduced, the pressure is relieved to a specified pressure, and the process returns to step 88. When the determination at step 91 is NO, the first switching valve M
It outputs an OFF command to the CS and the second switching valve BCS, and outputs a command to stop the pump OP.

Next, FIG. 9 is a flowchart showing the flow of the boosting failure assisting operation, and each step will be described below. In this flowchart, steps 94 and 95 are added as a boost failure detection step before the brake depression determination in step 82, and the boost assistance operation is a boost assistance limit detection step after the brake depression determination. It differs from FIG. 8 in that 84 and step 85 are deleted. That is, in step 94, the state of the booster 2 is detected based on the detection value from the booster negative pressure sensor 9, and in the next step 95, it is determined whether or not the booster negative pressure has decreased to the failure level. Is done.

As a result, when the assist of the booster 2 reaches the limit for the braking operation including the failure of the booster 2 during the braking operation by the normal driver, the braking by the master cylinder pressure is performed. Instead, when the braking operation is performed by the hydraulic pressure generated by the pump OP and the braking operation is performed beyond the assisting limit of the booster 2, the braking operation force does not suddenly increase and the operation force is not increased. A sudden change can be prevented, and when the booster fails due to a device failure, a boost pressure source failure, or the like, the same braking force as when the booster 2 is normal is obtained and used as a fail-safe at the time of failure. be able to.

(Other Embodiments) Although the present invention has been described with reference to the first embodiment, the specific structure is not limited to this, and at least the structure of the automatic brake device shown in FIG. 1 is provided. Various changes and additions are included in the invention described in claim 1 as long as they are made.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a main part of an automatic brake device according to a first embodiment.

FIG. 2 is an overall circuit diagram showing the automatic brake device according to the first embodiment.

FIG. 3 is a diagram showing a maximum flow control state by a flow control valve used in the automatic brake device according to the first embodiment;

FIG. 4 is a view showing a fully opened state in which a flow rate is not regulated by a flow rate control valve used in the automatic brake device according to the first embodiment;

FIG. 5 is a control block diagram showing an electronic control system of the automatic brake device according to the first embodiment.

FIG. 6 is a flowchart illustrating an automatic braking operation of the automatic braking device according to the first embodiment.

FIG. 7 shows V in the automatic brake device according to the first embodiment.
5 is a flowchart illustrating a DC / TCS operation.

FIG. 8 is a flowchart showing boost assisting operation in the automatic brake device according to the first embodiment.

FIG. 9 is a flowchart showing a boost failure assisting operation in the automatic brake device according to the first embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Brake pedal 2 Negative pressure booster 3 Master cylinder 4 Reservoir tank 6 Fluid pressure adjustment actuator 7RR, 7FL, 7FR, 7RL Wheel cylinder 8 Brake switch 9 Negative pressure sensor in booster 10 Primary master cylinder pressure sensor 11 Secondary master cylinder pressure sensor MCS 1st switching valve BCS 2nd switching valve OP Pump VOV Flow control valve

Claims (5)

[Claims] 1. A master cylinder for generating a master cylinder pressure corresponding to a driver's operation force, an auxiliary hydraulic pressure source for generating a hydraulic pressure separately from the master cylinder pressure, and a wheel according to a supplied brake hydraulic pressure. A wheel cylinder that applies braking force, and by controlling the hydraulic pressure from the auxiliary hydraulic pressure source according to a control command from the brake controller and supplying it to the wheel cylinder, automatically without depending on the driver's braking operation. An automatic brake device for generating a braking force, wherein the auxiliary hydraulic pressure source is included in a wheel lock prevention device disposed between a master cylinder and a wheel cylinder, and the brake fluid is sucked from a reservoir tank. And a pump having a discharge pressure in accordance with a drive control command from the master cylinder and the wheel lock prevention device. A first switching valve which is normally in a communication state and is switched to a non-communication state in response to a command from a brake controller; and is disposed in a communication path between the master cylinder and the suction side of the pump, and is normally in a non-communication state. A second switching valve for switching to communication in accordance with a command from the pump, a check valve disposed between the discharge side of the pump and the first switching valve, and allowing communication only in the direction of the first switching valve; And a flow control valve disposed between the first switching valve and the first switching valve, the flow control valve restricting a flow rate from the first switching valve in communication with the master cylinder in accordance with a discharge pressure from the pump whose drive is controlled. An automatic braking device, characterized in that: 2. The automatic brake device according to claim 1, wherein the flow rate control valve uses a discharge pressure from a pump as an operation signal pressure, and the flow rate is controlled by a variable throttle action that increases a throttle amount of a flow path area as the discharge pressure increases. An automatic brake device, characterized in that it is a valve for limiting the pressure. 3. The automatic brake device according to claim 1, wherein when the brake controller inputs an automatic brake command, the brake controller issues a command to disconnect the first switching valve and to communicate the second switching valve. Output, calculates the target hydraulic pressure in response to the target deceleration instruction, and outputs an operation control command to the pump in accordance with the gradient reaching the target hydraulic pressure, thereby increasing the wheel cylinder pressure and controlling the first switching valve. When the wheel cylinder pressure is maintained by outputting a stop command to the pump while the communication is not performed and the increased wheel cylinder pressure is reduced, a command to connect the first switching valve is output, and the pressure reduction gradient is output. By outputting an operation control command to the pump in accordance with the pressure, the wheel cylinder pressure is increased by the pump discharge pressure, and the wheel cylinder pressure via the flow control valve whose flow path cross-sectional area is adjusted The balance between open, automatic braking system being characterized in that the means for pressure reduction control of the wheel cylinder pressure. 4. The automatic brake device according to claim 1, wherein when the brake controller inputs a command for controlling the braking force of each wheel when the brake is not operated, the first switching valve is disconnected and the second switching is performed. Means for outputting a command to connect the valves and a command to operate the pump, and outputting to the pressure increasing valve and the pressure reducing valve included in the wheel lock prevention device a command to control the pressure increase / hold / pressure reduction of each wheel. An automatic braking device, characterized in that: 5. The automatic brake device according to claim 1, wherein boosting assist limit detecting means for detecting an assist limit of a braking operation by a booster provided between the brake pedal and the master cylinder, and detecting the master cylinder pressure. A master cylinder pressure sensor for detecting, when the boost controller detects a boost assist limit including a booster failure, calculates a target assist amount based on the master cylinder pressure detection value, and disconnects the first switching valve. An automatic brake device for outputting a command to connect the second switching valve to the pump, and outputting to the pump an operation command for obtaining a target hydraulic pressure corresponding to the target assisting amount.