JPH0976890A - Brake fluid pressure controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To always secure sufficient pressure intensifying ability and pressure reducing ability in a brake fluid pressure controller in which pressure intensifying control and pressure reducing control for a wheel cylinder are carried out. SOLUTION: Pressure intensifying control is carried out by feeding brake fluid in a reservoir tank 54, which is provided with an original position restoring function, to wheel cylinders 28, 30. Pressure reducing control is carried out by letting the brake fluid in the wheel cylinders 28, 30 flow to the reservoir tank 54. When restoration of the brake fluid in the reservoir tank 54 to a reference value is required, the reservoir tank 54 is pressurized by means of a master cylinder 12, and a piston 54 is displaced against energizing force of a spring 54d. As a large spring constant is provided in the spring 54d, the piston 54d is returned to the original position at once after a master cylinder pressure is removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake fluid pressure control device, and more particularly to a pressure increase control for supplying a brake fluid in a reservoir tank to a wheel cylinder to increase the wheel cylinder pressure, and a brake in the wheel cylinder. The present invention relates to a brake fluid pressure control device that controls a brake fluid pressure of a brake device that performs a pressure reducing control that causes fluid to flow into the reservoir tank to reduce the wheel cylinder pressure.

[0002]

2. Description of the Related Art Conventionally, for example, JP-A-7-52768.
As disclosed in the publication, there is known a brake device that increases or decreases the wheel cylinder pressure according to the running state of a vehicle. The above-mentioned conventional apparatus includes a fluid reservoir for storing brake fluid and a reservoir tank for storing brake fluid in the hydraulic circuit of the brake apparatus.

A predetermined amount of brake fluid is stored in the above-mentioned liquid storage chamber. The brake fluid in the liquid storage chamber is pumped up by a pump and supplied to the wheel cylinder under a predetermined operating condition. When the brake fluid is supplied to the wheel cylinder in this way, the wheel cylinder pressure is increased and the braking force is increased.

A reservoir tank is connected to the wheel cylinder via a valve mechanism. The valve mechanism is opened under a predetermined operating condition where the braking force should be reduced. When the valve mechanism is opened, the wheel cylinder and the reservoir tank are brought into communication with each other, and the wheel cylinder pressure is reduced as the brake fluid flows out. When the wheel cylinder pressure is reduced in this way, the braking force generated by the wheels is reduced.
As described above, according to the above-described conventional device, the wheel cylinder pressure can be increased or decreased by appropriately driving the pump for increasing pressure and the valve mechanism for reducing pressure to control the braking force. .

[0005]

By the way, in the above-mentioned conventional apparatus, the amount of the fluid in the liquid storage chamber becomes smaller as the fluid is pumped from the liquid storage chamber toward the wheel cylinder. Therefore, the fluid in the liquid reservoir decreases as the control for increasing the wheel cylinder pressure (hereinafter referred to as pressure increasing control) is executed. Therefore, in order to always exert a sufficient pressure increasing capability, it is necessary to replenish the amount of fluid flowing out of the liquid reservoir with the execution of the pressure increasing control to the liquid storing chamber after the pressure increasing control is completed. .

On the other hand, in the above conventional apparatus, the amount of fluid in the reservoir tank increases as the fluid flows out from the wheel cylinder toward the reservoir tank. Therefore, the fluid in the liquid storage chamber increases as the control for reducing the wheel cylinder pressure (hereinafter referred to as pressure reduction control) is executed. Therefore, in order to obtain a sufficient decompression ability, it is necessary to secure a sufficient empty capacity in the reservoir tank.

Therefore, in the above-mentioned conventional apparatus, in order to always ensure a sufficient pressure increasing ability and pressure reducing ability, the brake fluid does not flow into the reservoir tank.
It is necessary to quickly replenish the fluid reservoir with brake fluid. However, the above publication does not disclose a method of replenishing the brake fluid that satisfies the above requirement. In this respect, the above-mentioned conventional device lacks consideration for ensuring sufficient pressure increasing ability and pressure reducing ability.

The present invention has been made in view of the above points, and it is possible to secure sufficient pressure increasing ability and pressure reducing ability in a brake device that executes both pressure increasing control and pressure reducing control. An object of the present invention is to provide a brake fluid pressure control device that controls the brake fluid pressure.

[0009]

The above-mentioned object is defined in claim 1.
As described in (1), the brake fluid in the reservoir tank having the home position return function is supplied to the wheel cylinder to increase the wheel cylinder pressure, and the brake fluid in the wheel cylinder is discharged to the reservoir tank. In a brake fluid pressure control device for controlling a brake fluid pressure of a brake device for performing a pressure reduction control for reducing a wheel cylinder pressure, a pressurizing unit for pressurizing a reservoir tank, and the reservoir after the pressurizing process by the pressurizing unit. It is achieved by a brake fluid pressure control device including an atmosphere opening means for opening the tank to substantially atmospheric pressure.

In the present invention, the wheel cylinder pressure is increased by pumping the brake fluid in the reservoir tank to the wheel cylinder. When pumping the brake fluid to the wheel cylinder, it is necessary to suck the piston in the reservoir tank in the direction in which the volume of the reservoir tank decreases against the force of returning to the original position.

Further, the wheel cylinder pressure is reduced by the brake fluid in the wheel cylinder flowing out toward the reservoir tank. When flowing the brake fluid into the reservoir tank, the piston in the reservoir tank is resisted against the force to return to the original position,
It is necessary to displace the reservoir tank in the direction of increasing its volume. Since the wheel cylinder pressure is high, when the piston is displaced in the direction of increasing the volume of the reservoir tank, a large original position returning force acts on the piston.

When the reservoir tank is pressurized by the pressurizing means, the piston in the reservoir tank is displaced in the direction in which the volume of the reservoir tank increases. At this time, the displacement of the piston is performed against a large return force to the original position. Therefore, when the reservoir tank is opened to the atmospheric pressure by the atmosphere releasing means, the piston of the reservoir tank immediately returns to the original position, and the brake fluid in the reservoir tank is quickly adjusted to the reference amount. It

Further, as described in claim 2, the above object is to provide the brake fluid pressure control device according to claim 1, wherein the pressurizing means causes the brake fluid to flow out in accordance with the stroke amount of the brake pedal. It is also achieved by a brake fluid pressure control device including a fluid generation mechanism, a valve mechanism arranged between the brake generation mechanism and the reservoir tank, and a pulse drive device for pulse-driving the valve mechanism. .

In the present invention, pressurization of the reservoir tank is performed by supplying fluid from the fluid generating mechanism to the reservoir tank via the valve mechanism. The fluid generation mechanism flows out the brake fluid according to the stroke amount of the brake pedal. Therefore, the pressurization of the reservoir tank is performed under the condition where the brake pedal force is applied to the brake pedal. Further, the inflow of the fluid into the reservoir tank is performed by pulse-driving the valve mechanism by the pulse driving device. Therefore, the fluid does not suddenly flow in when pressurizing the reservoir tank, and abrupt stroke change of the brake pedal is prevented.

[0015] The above object is as described in claim 3.
The brake fluid pressure control device according to claim 1, wherein the pressurizing means is a valve mechanism disposed between the wheel cylinder and the reservoir, and the valve mechanism is opened at the end of the pressure increase control. It is also achieved by a brake fluid pressure control device including the valve drive device.

In the present invention, the valve mechanism controls the electrical connection between the wheel cylinder and the reservoir tank. The valve drive device opens the valve mechanism when the pressure increase control is completed. The pressure increase control is performed by pressure-feeding the fluid in the reservoir tank to the wheel cylinder. Therefore, when the valve mechanism is opened at the time when the pressure increase control is completed, the fluid pressure-fed into the wheel cylinder flows into the reservoir tank,
The amount of fluid in the reservoir tank is returned to the initial value.

[0017] The above object is as described in claim 4.
The pressure increase control for supplying the brake fluid in the reservoir tank to the wheel cylinder to increase the wheel cylinder pressure and the pressure reduction control for causing the brake fluid in the wheel cylinder to flow out into the reservoir tank to reduce the wheel cylinder pressure are performed. In a brake fluid pressure control device for controlling a brake fluid pressure of a brake device, a pressurizing means for pressurizing a reservoir tank, a fluid amount detecting means for detecting an amount of brake fluid in the reservoir tank, and a brake fluid in the reservoir tank. It is also achieved by a brake fluid pressure control device that includes a pump mechanism that pumps up pressure and pumps it to the master cylinder, and pump drive means that drives the pump mechanism so that the brake fluid in the reservoir tank becomes a reference amount. .

In the present invention, the amount of brake fluid in the reservoir tank increases as the reservoir tank is pressurized by the pressurizing means. The increased brake fluid is reliably returned from the reservoir tank to the master cylinder by the pump drive means driving the pump mechanism based on the detection result of the fluid amount detection means.

[0019]

FIG. 1 shows a system configuration diagram of an embodiment of the present invention. The brake fluid pressure control device shown in the present embodiment constitutes a part of a vehicle brake device. The system of the present embodiment has an electronic control unit (ECU) 1 described later.
It is controlled by 0.

The master cylinder 12 is a so-called tandem type cylinder having two pressurizing chambers therein.
The brake pedal 14 is attached to the input shaft of the master cylinder 12.
Are connected. When the brake pedal 14 is depressed, hydraulic pressures corresponding to the brake pedal force are generated in the two pressurizing chambers of the master cylinder 12, respectively.

A fluid tank 16 for storing brake fluid is arranged above the master cylinder 12. When the brake fluid flows out from the master cylinder 12 and the brake fluid in the master cylinder 12 decreases, the master tank 12 and the master cylinder 12 are appropriately discharged from the fluid tank 16.
Brake fluid is replenished inside.

The brake pedal 14 is provided with a brake switch 18 which outputs an ON output when the brake pedal 14 is depressed. The output signal of the brake switch 18 is supplied to the ECU 10. ECU10
Is whether or not the brake pedal 14 is stepped on the basis of the output signal of the brake switch 18, that is,
It is determined whether or not the brake is being operated.

In the two pressure chambers of the master cylinder 12,
The hydraulic pressure passages 20 and 22 communicate with each other. The hydraulic passages 20 and 22 are respectively connected to independent hydraulic circuits that communicate with the wheel cylinders of the two wheels. These two
Since the two hydraulic circuits are the same in structure, only the hydraulic circuit communicating with the hydraulic passage 20 will be described here.

The fluid pressure passage 20 includes the first solenoids 24, 2
6 are in communication. The first solenoids 24 and 26 are normally open 2 which are in the cutoff state only while the ON signal is supplied.
Position solenoid valve. Fluid pressure passages 32 and 34, which communicate with the wheel cylinders 28 and 30, respectively, are connected downstream of the first solenoids 24 and 26. Therefore, under the condition that the ON signal is not supplied to the first solenoids 24 and 26, the master cylinder 12 and the wheel cylinders 28 and 30 are in a conductive state. The first solenoids 24 and 26 are EC
Driven by U10.

The fluid pressure passage 32 is communicated with a fluid pressure passage 40 which communicates between the second solenoid 36 and the third solenoid 38. Further, in the hydraulic pressure passage 34, the second solenoid 4
A hydraulic passage 46 that communicates between the second solenoid 3 and the third solenoid 44 is in communication. The second solenoids 36, 42 and the third solenoids 38, 44 are normally closed two-position solenoid valves that are in a conductive state only while an ON signal is supplied. Second
Solenoids 36, 42 and third solenoids 38, 44
Are driven by the ECU 10.

Hydraulic passage 3 of second solenoids 36, 42
A discharge port 48a of a pump mechanism 48 communicates with a side opposite to 2, 34 via a check valve 46, and an inflow port 50a of a master cylinder pressure pilot type relief valve (PRV) 50 communicates therewith. There is. On the other hand, on the side opposite to the hydraulic pressure passages 32, 34 of the third solenoid valves 38, 44,
The inflow port 48b of the pump mechanism 48 communicates with the check valve 52, and the outflow port 50b of the PRV 50 and the reservoir tank 54 communicate with each other.

The pump mechanism 48 has a drive motor 56 as a drive source, and when the drive motor 56 operates, the brake fluid stored in the reservoir tank 54 is pressure-fed. Therefore, the second solenoids 36, 4
Drive motor 56 under the condition that the ON signal is supplied to 2
When is activated, the discharge pressure of the pump mechanism 48 can be introduced to the wheel cylinders 28 and 30.

The reservoir tank 54 is provided with a piston 54a and a retainer 54b which are liquid-tightly and slidably disposed therein. Piston 54a and retainer 5
4b can slide in the reservoir tank 54 independently of each other. The reservoir tank 54 also includes a spring 5 that biases the piston 54a toward the retainer 54b.
4c and a retainer 54b are provided with a spring 54d for urging the retainer 54b toward the piston 54a. The piston 54a and the retainer 54b are held in the reservoir tank 54 with the position where the retainer 54b comes into contact with the stepped portion of the housing of the reservoir tank 54 as the original position. In the present embodiment, the spring constant of the spring 54c is set to be small and the spring constant of the spring 54 is set to be large for the reasons described later.

The PRV 50 has a pilot pressure supply port 50c communicating with the master cylinder 12 via the hydraulic pressure passage 20. The PRV 50 releases the hydraulic pressure of the inflow port 50a toward the outflow port 50b when the hydraulic pressure acting on the inflow port 50a becomes higher than a predetermined pressure as compared with the hydraulic pressure acting on the pilot pressure supply port 50c. In addition, when the hydraulic pressure acting on the outlet 50b becomes higher than the hydraulic pressure acting on the pilot pressure supply port 50c, the hydraulic pressure at the outlet 50b is directed toward the pilot pressure supply port 50c. It is a relief valve that opens.

FIG. 2 shows a block diagram of the PRV 50. FIG.
As shown in FIG. 5, an orifice 60 is arranged at the inflow port 50a of the PRV 50. Orifice 60 is seat 6
Built into 2. A through-hole 62a is provided in the center of the seat 62. The through hole 62a is closed or opened by the ball portion 64a of the shaft 64 with a ball.

The seat 62 includes a first shaft guide 66.
Are fitted. The second shaft guide 68 is in contact with the end of the first shaft guide. The first shaft guide 66 is provided with a through hole for slidably holding the shaft 64 with balls. Further, the second shaft guide 68 is provided with a pilot hydraulic chamber 68a that accommodates the end portion of the shaft 64 with a ball and communicates with the pilot pressure supply port 50c. Therefore, when the master cylinder pressure P _{M / C} is introduced to the pilot pressure supply port 50c, the pressure P _{M / C} is changed to the pilot hydraulic chamber 68.
A force that is guided to a and presses the ball-equipped shaft 64 toward the seat 62 is generated.

Inside the first shaft guide 66, a spring 70 for pressing the ball-equipped shaft 64 toward the seat 62 is provided. Therefore, the urging force of the spring 70 and the urging force resulting from the master cylinder pressure P _{M / C} act on the ball-equipped shaft 64 as a pressing force in the seat 62 direction. The relief pressure of the PRV 50 is determined by this pressing force.

The first shaft guide 66 has a through hole 6 for communicating its internal space with the outlet 50b of the PRV 50.
6a is provided. Therefore, the inflow hole 5 of the PRV 50
When the pressure exceeding the relief pressure of the PRV 50 acts on 0a, and as a result, the ball-equipped shaft 64 separates from the seat 62, the inflow hole 50a and the outflow hole 50b become conductive. When the inflow hole 50a and the outflow hole 50b are brought into conduction, the brake fluid flows out from the inflow port 50a toward the outflow port 50b, and further increase in pressure acting on the inflow port 50a is prevented.

An O-ring 73 and a backup ring 74 surrounding the outer circumference of the ball-equipped shaft 64 are fitted to the first shaft guide 66. Therefore, the first
An appropriate sealing property is ensured between the shaft guide 66 and the shaft 64 with balls. Further, a cup seal 72 made of an elastic body is arranged on the outer periphery of the first shaft guide 66. The cup seal 72 is
Cylindrical portion 72a surrounding the outer periphery of the first shaft guide 66
And a cap portion 72b that expands to the outer periphery of the cylindrical portion 72a. Umbrella portion 72b of cup seal 72
Is the housing 7 of the PRV 50 at its outer peripheral edge.
It is in contact with the inner circumference of 6.

Between the outer peripheral surface of the first shaft guide 66 and the inner peripheral surface of the housing 76, and the second shaft guide 6
A predetermined clearance is provided between the outer peripheral surface of 8 and the inner peripheral surface of the housing 76. Therefore, the outlet 50
When a differential pressure is generated between b and the pilot pressure supply port 50c, the differential pressure acts on both sides of the cap portion 72b of the cup seal 72.

The cup seal 72 is provided on the outlet 50b side,
When the pressure higher than that on the pilot pressure supply port 50c side acts, the diameter of the umbrella portion 72b is reduced, and on the pilot pressure supply port 50c side, a pressure higher than that on the flow outlet 50b side acts. At this time, the umbrella portion 72b is configured to expand its diameter. When the diameter of the umbrella portion 72b is reduced, a clearance is generated between the cup seal 72 and the housing 76, and the outlet 50
b and the pilot pressure supply port 50c are brought into conduction. On the other hand, when the diameter of the umbrella portion 72b is increased, the sealability between the cup seal 72 and the housing 76 is improved, and the outflow port 50b and the pilot pressure supply port 50c are shut off. Therefore, P
According to the RV50, when the pressure on the pilot pressure supply port 50c side is higher than that on the outflow port 50b side,
When the flow of the brake fluid from the pilot pressure supply port 50c side toward the outflow port 50b side is blocked and the pressure on the pilot pressure supply port 50c side becomes lower than the pressure on the outflow port 50b side, The flow of brake fluid from the outlet 50b side to the pilot pressure supply port 50c side can be allowed.

According to the brake fluid pressure control device having the above structure, the first to third solenoids 24, 26; 36, 4
2; 38, 44, when the ON signal is not supplied to any of the master cylinder 12 and the wheel cylinder 28,
30 and the pump mechanism 44 and the reservoir tank 54 are disconnected from the wheel cylinders 28 and 30. Therefore, in such a case, the configuration as a normal brake device is realized. Hereinafter, this mode is referred to as a normal pressure increasing mode.

In the brake fluid pressure control device having the above structure, the first solenoids 24 and 26 and the second solenoid 3
6, 42 to supply an ON signal to the third solenoid 3
If the wheels 8 and 44 are kept off, the wheel cylinder 2
The discharge port 48a of the pump mechanism 46 can be communicated with 8 and 30. Therefore, under such circumstances, the drive motor 5
6 is activated, the brake fluid in the reservoir tank 54 is transferred to the wheel cylinder 28,
It is pumped into 30. In this case, the wheel cylinder pressure is
The pressure is increased by the discharge pressure of the pump mechanism 48. Hereinafter, this mode is referred to as a pump pressure increasing mode.

When the pump pressure increasing mode is executed, the brake fluid is sucked from the inside of the reservoir tank 54 by the pump mechanism 48. In order to suck the brake fluid from the reservoir tank 54, the piston 54a needs to be displaced upward in FIG. 1 against the biasing force of the spring 54c. On the other hand, in the present embodiment, as described above, the spring constant of the spring 54c is set to a sufficiently small value. Therefore, according to the system of the present embodiment, the piston 54a can be given a necessary displacement without applying a large load to the pump mechanism 48.

Further, when the pressure on the discharge port 46a side of the pump mechanism 46 unduly rises during execution of the pump pressure increasing mode, the PRV 50 operates to relieve the pressure on the discharge port 46a side. Therefore, an unduly large pressure does not act on the discharge port 46a side of the pump mechanism 46.

In the brake fluid pressure control device having the above structure, the first solenoids 24 and 26 and the third solenoid 3
An ON signal is supplied to 8, 44, and the second solenoid 3
If the wheels 6 and 42 are kept off, the wheel cylinder 2
8 and 30 and the reservoir tank 54 can be electrically connected. Wheel cylinders 28, 30 and reservoir tank 54
When and are brought into conduction, the brake fluid in the wheel cylinder can be released into the reservoir tank 54 to reduce the wheel cylinder pressure. Hereinafter, this mode is referred to as a pressure reduction mode.

When the pressure reducing mode is executed in the brake fluid pressure control device, the amount of brake fluid in the reservoir tank 54 increases. Therefore, the piston 54a and the retainer 54b of the reservoir tank 54 are displaced downward in FIG. 1 against the urging force of the spring 54d as the execution of the pressure reducing mode is continued.

As described above, according to the flexure liquid pressure control device of this embodiment, the normal pressure increasing mode, the pump pressure increasing mode, and the pressure reducing mode can be realized. Further, by repeatedly executing the normal pressure increasing mode and the pressure decreasing mode, or the pump pressure increasing mode and the pressure decreasing mode, it is possible to realize a mode for holding the wheel cylinder pressure (hereinafter, a holding mode). If the normal pressure increasing mode, the holding mode, and the pressure reducing mode can be realized, the well-known antilock brake control (ABS control) can be realized. Further, if the pump pressure increasing mode, the holding mode, and the pressure reducing mode can be realized, known traction control control (TRC control) and vehicle stability control control (VSC control) can be realized. Therefore, according to the brake fluid pressure control device of the present embodiment, the ECU 10 causes the first to third solenoids 24, 26; 36, 42; 38, 4 to follow the predetermined logic.
4 by controlling the drive motor 56 and the ABS
Control, TRC control, VSC control, etc. can be realized. Hereinafter, these controls will be collectively referred to as braking force control.

When the pump pressure increasing mode is executed while the braking force control is being executed, the brake fluid in the reservoir tank 54 is reduced and the piston 54a is displaced upward in FIG. In order to reliably increase the wheel cylinder pressure as the pump pressure increasing mode is executed, it is necessary to store a sufficient amount of brake fluid in the reservoir tank 54. Therefore, when the pump pressure increasing mode is executed, it is necessary to return the amount of brake fluid in the reservoir tank 54 to the reference value before the pump pressure increasing mode is executed again.

On the other hand, when the pressure reducing mode is executed during execution of the braking force control, the brake fluid in the reservoir tank 54 increases and the piston 54a is displaced downward in FIG. In order to surely reduce the wheel cylinder pressure by executing the pressure reducing mode, it is necessary to secure a sufficient empty capacity in the reservoir tank 54. Therefore, when the depressurization mode is executed, it is necessary to return the amount of brake fluid in the reservoir tank 54 to the reference value thereafter before the depressurization mode is executed again.

As described above, the piston 54a is biased from above and below by the springs 54c and 54d, and is held in the reservoir tank 54 with the position where the biasing forces are balanced as the original position. Therefore, if the reservoir tank 54 is opened to the atmosphere after the pump pressure increasing mode and after the pressure reducing mode ends, the spring 5
The piston 54a returns to the original position by the urging force of 4c and 54d, and as a result, the amount of brake fluid in the reservoir tank 54 returns to the reference value.

[0047] Figure 3, after the pressure reduction control is ended at time t _0, the pump reservoir tank 54 displacement state of the piston 54a generated when open to the atmosphere (curve shown by in FIG. 3), and at time t ₀ A piston 54 generated when the reservoir tank 54 is opened to the atmosphere after the pressure increase control is completed.
The displacement state (curve shown by in FIG. 3) of a is shown.

As described above, the spring 54d that biases the piston 54a upward in FIG. 1 has a large spring constant. Therefore, as shown in FIG. 3, when the piston 54a returns to the original position from the side where the reservoir tank 54 is filled with brake fluid (hereinafter referred to as the full side), the original position is quickly returned. Done. On the other hand, as described above, a small spring constant is given to the spring 54c that biases the piston 54a downward in FIG. Therefore, when the piston 54a returns to the original position from the side where the brake fluid of the reservoir tank 54 is empty (hereinafter referred to as the empty side), as shown in FIG. To be done.

Therefore, according to the system of this embodiment,
When the reservoir tank 54 is opened to the atmosphere after the depressurization mode is executed, the brake fluid amount in the reservoir tank 54 can be quickly set to the reference value, but the reservoir tank 54 is set to the atmosphere after the pump pressure increasing mode is executed. By opening the brake fluid, the amount of brake fluid in the reservoir tank 54 cannot be promptly set as the reference value.

Therefore, in this embodiment, the piston 5
When it is necessary to return the piston 54a to the original position regardless of the direction in which the 4a is displaced,
By always displacing the piston 54a to the full side and then opening the reservoir tank 54 to the atmosphere, a quick return to the original position is realized.

FIG. 4 shows the ECU 1 which should realize such a function.
0 shows a flowchart of an example of a routine executed by 0.
The routine shown in FIG. 4 is started, for example, after the ignition switch is turned on, the execution of the braking force control is started, or at predetermined time intervals.

When the routine shown in FIG. 4 is started, first, at step 100, it is judged if the braking force control is being executed. If the braking force control is being executed, the routine of this time is ended without performing the subsequent processing. On the other hand, if it is determined that the braking force control is not being executed, the process of step 102 is executed.

In step 102, the brake switch 1
It is determined whether or not the ON output is issued from 8, that is, whether or not the brake operation is performed. As a result, when the brake switch 18 is not turned on, the routine of this time is ended without executing the subsequent processing. On the other hand, when the brake switch 18 is on,
Proceeding to step 104, the third solenoid 38, 44,
After pulse driving in a predetermined pattern, this routine is ended.

In the system of this embodiment, when the ON signal is supplied to the third solenoids 38 and 44 while maintaining the first solenoids 24 and 26 and the second solenoids 36 and 42 in the OFF state, the master cylinder 20 and the reservoir tank 5
4 can be brought into conduction. Therefore, when the process of step 104 is executed, the master cylinder pressure P _{M / C} corresponding to the brake pedal force is supplied to the reservoir tank 54, and the piston 54a of the reservoir tank 54 is displaced to the full side. .

When the brake fluid flowing out of the master cylinder 12 flows into the reservoir tank 54, a large stroke change occurs in the brake pedal 14. On the other hand, in the present embodiment, in step 104, the third driving is performed by pulse driving according to a predetermined pattern.
The solenoids 38 and 44 are to be opened. Therefore, the brake fluid does not suddenly flow from the master cylinder 12 into the reservoir tank 54,
It is possible to suppress the discomfort felt by the driver.

By the way, the reservoir tank 54 communicates with the outlet 50b of the PRV 50 as described above. Further, the PRV 50 is configured so that the pressure at the outlet 50b is always kept at the master cylinder pressure P _{M / C} or less. Therefore, under the condition that the master cylinder pressure P _{M / C} is atmospheric pressure, that is, under the condition that the brake pedal 14 is not depressed, the reservoir tank 54 is opened to atmospheric pressure. Therefore, according to the system of the present embodiment, when the brake pedal 14 is released after the process of 104 is executed, the reservoir tank 54 is opened to the atmosphere,
The original position of the piston 54a is promptly returned.

FIG. 5 shows a time chart for explaining the operation when the routine shown in FIG. 4 is executed by the ECU 10 after the ignition switch of the vehicle is turned on. When the ignition switch is turned on in the vehicle, the brake pedal is normally depressed. Therefore, as shown in FIG. 5 (A), when the ignition switch is turned on at time t ₀ , FIG.
As shown in FIG. 5, the brake switch 18 starts to output an ON signal, and as shown in FIG. 5B, the master cylinder pressure P _{M / C} starts to increase.

The braking force control is not executed immediately after the ignition switch is turned on. Therefore, after the time t ₀ , the conditions of the above steps 100 and 102 are both satisfied, and the ON signal is output to the third solenoid in a predetermined pattern as shown in FIG. 5 (D). As a result, the brake fluid is gradually supplied to the reservoir tank 54. At this time, the pedal stroke of the brake pedal 14 changes stepwise as shown in FIG. Then, thereafter, when the brake pedal is released, the amount of brake fluid in the reservoir tank 54 is quickly adjusted to the reference value.

As described above, if the ECU 10 executes the routine shown in FIG. 4 each time the ignition switch is turned on, the brake fluid amount in the reservoir tank 54 is set as a reference value every time the ignition key is turned on. The value can be adjusted. Further, if the ECU 10 executes the routine shown in FIG. 4 under an appropriate condition while the vehicle is traveling, the brake fluid amount in the reservoir tank 54 at the time when the braking amount control is started is accurately referenced. The value can be adjusted. Therefore, according to the brake fluid pressure control device of the present embodiment, when the pump pressure increasing mode is executed, it is possible to always exert a sufficient pressure increasing ability, and when the pressure reducing mode is executed, It is possible to exert sufficient decompression ability.

In the above embodiment, the normal pressure increasing mode and the pump pressure increasing mode are used for the pressure increasing control described above, the pressure reducing mode is used for the pressure reducing mode described above, and the reservoir tank 54 is used for the reservoir tank described above. , And the cup seal 72 of the PRV 50 corresponds to the above-mentioned atmosphere opening means. Further, under the situation where the master cylinder 12 is generating the master cylinder pressure P _{M / C} , the ECU 10 follows the processing of steps 100 to 104 and the third solenoid 3
The above-mentioned pressurizing means is realized by controlling 8, 44. Here, the fluid generating mechanism, the valve mechanism, and the pulse driving device according to the second aspect of the invention are the master cylinder 12, the third solenoids 38, 44, and the ECU, respectively.
10 are respectively configured.

FIG. 6 shows a system configuration diagram of the second embodiment of the present invention. In FIG. 6, the same parts as those shown in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. The brake fluid pressure control apparatus of the first embodiment described above is a mechanism for keeping the reservoir tank 54 at the master cylinder pressure P _{M / C} or less by the cup seal 72 built in the PRV 50, that is, opening the reservoir tank 54 to the atmospheric pressure. The mechanism to do is realized. However, the mechanism for opening the reservoir tank 54 to the atmospheric pressure is not limited to this.

That is, the mechanism for opening the reservoir tank 54 to the atmosphere is such that the reservoir tank 54 allows only the flow from the reservoir tank 54 side to the downstream side of the first solenoid 26 as shown in FIG. It can also be realized by providing. Further, a check valve 82 that allows only the flow from the reservoir tank 54 side toward the upstream side of the pump mechanism 48 is provided, and at least one of the second solenoids 36 and 42 is turned on at the timing when the reservoir tank 54 should be opened to the atmosphere. Can also be realized by supplying. Further, it can be realized by supplying an ON signal to the third solenoids 38, 44 at the timing when the reservoir tank 54 should be opened to the atmosphere without providing the check valve mechanism.

In this embodiment, the check valve 80, the check valve 82 and the second solenoids 36, 42 or the third solenoids 38, 44 correspond to the atmosphere opening means described in claim 1. . By the way, the above-mentioned first and second
According to the embodiment, since the piston 54a of the reservoir tank 54 is moved regardless of the braking force control, the piston 54a
It is possible to enjoy the advantage that the sticking of a can be prevented.

FIG. 7 shows a system configuration diagram of the third embodiment of the present invention. In FIG. 7, the same parts as those shown in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. The brake fluid pressure control system according to the present embodiment includes a second pump mechanism 84 that communicates with the fluid tank 16 disposed above the master cylinder 12. A check valve 86 is provided on the inflow side of the second pump mechanism 84, and a check valve 88 is provided on the outflow side thereof. The check valve 88 communicates with the hydraulic passage between the second solenoids 36, 42 and the pump mechanism 48. The second pump mechanism 84 includes a second drive motor 90 as a drive source, and when the drive motor 90 operates, the second pump mechanism 84 pressure-feeds the brake fluid stored in the fluid tank 16.

Therefore, the first to third solenoids 24, 2
If the second drive motor 90 is operated under the condition that the ON signal is supplied to 6; 36, 42; 38, 44, the reservoir tank 54 can be operated even if the brake pedal 14 is not depressed.
Brake fluid can be pumped to. The brake fluid pressure control apparatus of the present embodiment is characterized in that the amount of brake fluid in the reservoir tank 54 is used as a reference value promptly and reliably after execution of the braking force control using such a function is completed. have.

FIG. 8 shows the ECU 1 for realizing the above function.
0 shows a flowchart of an example of a routine executed by 0.
It should be noted that this routine is started every time the execution of the braking force control is started, and is executed at regular time intervals.

When this routine is started, first, at step 200, it is judged if the braking force control has ended. As a result, when it is determined that the braking force control is still being executed, the routine of this time is ended without executing the subsequent processing. On the other hand, if it is determined that the braking force control has ended, the process of step 202 is executed.

In step 202, the first to third
A process of supplying an ON signal to the solenoids 24, 26; 36, 42; 38, 44 is executed. When the processing of this step is executed, the first solenoids 24 and 26 are closed,
The second and third solenoids 36, 42; 38, 44 are opened.

When the above processing is completed, the next step 2
At 04, the second drive motor 90 is turned on. When the second drive motor is turned on by executing this step, the fluid tank 16 moves to the reservoir tank 5
Brake fluid pumping to No. 4 is started.

At step 206, the counter C counts.
Will be upgraded. Then, in step 208, the coun
C is the predetermined value C₀It is determined whether or not the above. C₀Is
In the reservoir tank 54, brake full exceeding the standard value
Preset as the time required for the
This is the specified value. C ≧ C₀If is not established,
After this, this routine ends without any further processing.
It is. On the other hand, already C ≧ C ₀Is determined to hold
If so, turn off the second drive motor in step 210.
Then, in step 212, the first to third solenos are set.
Ids 24, 26; 36, 42; 38, 44 are turned off
Then, in step 214, the counter C is cleared.
Then, this routine is finished.

In the above embodiment, the ECU 10
By operating the second pump mechanism 84 and the second drive motor 90 in accordance with the processing of steps 202 to 210, the pressurizing means according to claim 1 is realized. FIG. 9 shows a system configuration diagram of the fourth embodiment of the present invention.
In FIG. 9, the same parts as those shown in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. The brake fluid pressure control apparatus according to the present embodiment includes a fluid amount sensor 92 that detects the amount of brake fluid in the fluid tank 16 disposed above the master cylinder 12.

With the execution of the braking force control, the brake fluid in the reservoir tank 54 is changed to the wheel cylinders 28, 3.
Outflow toward 0 occurs when the pump pressure increasing mode is performed in the brake fluid pressure control device. During execution of the pump pressure increasing mode, the brake fluid does not flow out from the master cylinder 12. Therefore, the brake fluid in the master cylinder 12 does not become insufficient, and the brake fluid in the fluid tank 16 does not decrease.

On the other hand, when the normal pressure increasing mode and the pressure decreasing mode are repeatedly executed by the braking force control, a large amount of brake fluid flows out from the master cylinder 12, and the amount of brake fluid in the fluid tank 16 is reduced. A large amount of brake fluid is stored in the reservoir tank 54 as compared with the reference value.

As described above, there is a correlation between the amount of brake fluid in the reservoir tank 54 and the amount of brake fluid in the fluid tank 16. Therefore, whether or not the amount of brake fluid in the reservoir tank 54 exceeds the reference value can be estimated based on the amount of brake fluid in the fluid tank 16. Further, when the amount of brake fluid in the reservoir tank 54 is larger than the reference value, it is not necessary to pressurize the reservoir tank 54, and thereafter the reservoir tank 54 is simply opened to the atmospheric pressure. The amount of brake fluid in 54 can be quickly returned to the reference value.

Therefore, in the brake fluid pressure device of the present embodiment, it is judged based on the brake fluid amount in the fluid tank 16 whether or not the brake fluid amount in the reservoir tank 54 is less than the reference value. As a result, the brake fluid is pumped to the reservoir tank 54 only when it is determined that the amount of brake fluid in the reservoir tank 54 does not reach the reference value.

FIG. 10 shows an ECU for realizing the above functions.
10 shows a flowchart of an example of a routine executed by 10. This routine is similar to the routine shown in FIG.
This routine is started each time the execution of the braking force control is started and is executed at regular time intervals. In this routine, the same steps as those in the routine shown in FIG. 8 are designated by the same reference numerals and the description thereof will be omitted.

That is, this routine is performed at step 200.
If it is determined that the braking force control has ended, the process proceeds to step 300, and the reserve amount of the brake fluid stored in the fluid tank 16 is decreased beyond the predetermined amount before and after the execution of the braking force control. Is determined. As a result, when the reserve amount has decreased below the predetermined amount, it is determined that the brake fluid amount in the reservoir tank 54 is larger than the reference value, and the routine of this time is performed without proceeding to the subsequent processing. Is ended. On the other hand, when it is determined that the reserve amount in the fluid tank 16 has not decreased below the predetermined amount, the brake fluid amount in the reservoir tank 54 may be smaller than the reference value. It is determined that the processing after step 202 is executed.

According to the brake fluid pressure control apparatus of the present embodiment, the brake in the reservoir tank 54 can be promptly performed immediately after the braking force control is executed without unnecessarily pressurizing the reservoir tank 54. The amount of fluid can be adjusted to the reference value. FIG. 11 shows a flowchart executed in the system of the fifth embodiment of the present invention. This embodiment can be realized by the brake fluid pressure device having the configuration shown in FIG. The routine shown in FIG. 11 is a regular interrupt routine that is activated every predetermined time.

When the routine shown in FIG. 11 is started, first, at step 400, it is judged if the execution of the braking force control has been started from the time of the previous processing to the time of the current processing. When it is determined that the braking force control is started, the flag XCBRK is set to "1" in step 402. On the other hand, if it is determined that the execution of the braking force control has not started, it is determined in step 404 whether or not the flag XCBRK is set to "1".

If it is determined in step 404 that XCBRK = 1 holds, it is determined that the braking force control is currently being executed, and then the process of step 406 is executed. On the other hand, when it is determined that XCBRK = 1 is not established, it is determined that the braking force control is not currently executed, and thereafter, this routine is ended without proceeding any processing.

In step 406, the cumulative time in the pressure reducing mode performed during execution of the braking force control is counted. Similarly, in step 408, the cumulative time in the pressure increasing mode is counted. Then, in step 410, the stroke amount of the piston 54a of the reservoir tank 54 is estimated based on these accumulated times according to a preset logic.

When the above processing is completed, the next step 4
12, the master cylinder pressure P _{M / C} exceeding a predetermined value
Is output or not. If the master cylinder pressure P _{M / C} is not output during execution of the braking force control, it can be determined that the brake fluid has not flowed out from the master cylinder 12. Assuming that the brake fluid does not flow out from the master cylinder 12,
It can be estimated that there is no change in the total amount of the brake fluid in the reservoir tank 54 and the brake fluid in the wheel cylinders 28, 30.

Therefore, if the above determination is made,
Following step 412, it is determined in step 414 whether the braking force control has ended. Then, if it is determined that the braking force control is not finished, the routine of this time is ended as it is, while if it is determined that the braking force control is ended, the routine proceeds to step 416, where the first
And the process of supplying the ON signal to only the third solenoids 24, 26; 38, 44 is performed.

When the ON signals are supplied to the first solenoids 24 and 26, the first solenoids 24 and 26 are closed, and when the ON signals are supplied to the third solenoids 38 and 44, the third solenoids 38 and Since 44 is opened,
The wheel cylinders 28 and 30 are in a state of being electrically connected only to the reservoir tank 54. Therefore, the brake fluid that has flowed out of the reservoir tank 54 accurately flows into the reservoir tank 54 from the wheel cylinders 28 and 30, and the brake fluid in the reservoir tank 54 accurately returns to the reference value.

If it is determined in step 412 that the master cylinder pressure P _{M / C} is being output during execution of the braking force control, the brake fluid flows out from the master cylinder 12 toward the wheel cylinders 28 and 30. Need to be aware of the possibility. Therefore, in such a case, simply returning the brake fluid in the wheel cylinders 28, 30 to the reservoir tank 54 cannot restore the brake fluid amount in the reservoir tank 54 to the reference value.

Therefore, if the above determination is made, it is determined in step 418 following step 412 whether or not the braking force control has been completed. Then, as a result, if it is determined that the braking force control is not ended, the routine of this time is ended as it is, while if it is determined that the braking force control is ended, the process proceeds to step 420 and the master is executed. The time required to pump up the brake fluid flowing out of the cylinder 12 from the reservoir tank 54 using the pump mechanism 48 is calculated based on the estimated stroke value of the reservoir tank estimated in step 410.

When the calculation of the time for driving the pump mechanism 48 is completed, in step 422, the ON signal is supplied to the second solenoids 36, 42, and the processing for driving the pump mechanism 48 is executed. In this way, when the pump mechanism 48 is driven, the excessive brake fluid that has flowed into the reservoir tank 54 is pressure-fed to the master cylinder 12 side via the second solenoids 36 and 42, and the inside of the reservoir tank 54. The amount of brake fluid is accurately and quickly returned to the reference value.

As described above, when the ECU 10 executes the routine shown in FIG. 11, the brake fluid amount in the reservoir tank 54 can be quickly returned to the reference value after the braking force control is executed. Therefore, also by the brake fluid pressure control device of the present embodiment, it is possible to always ensure a sufficient pressure increasing capability in the pressure increasing control and a sufficient pressure reducing control in the pressure reducing control while the vehicle is traveling.

In the above embodiment, the third solenoids 38 and 44 correspond to the valve mechanism described in claim 3,
The ECU 10 executes the processes of steps 414 and 416 to implement the valve drive system according to the third aspect. Further, in the above embodiment, the master cylinder 12 is the pressurizing means according to claim 4, and the pump mechanism 48.
The drive motor 56 and the drive motor 56 correspond to the pump mechanism described in claim 4, and the ECU 10 executes the steps 406 to 406.
By executing the processing of 410, the fluid amount detecting means according to claim 4 is realized, and by executing the processing of the steps 418 to 422 by the ECU 10, the pump driving means according to claim 4 is realized. It

[0090]

As described above, according to the first aspect of the present invention, by pressurizing the reservoir tank and then opening it to the atmosphere, the amount of fluid in the reservoir tank can be promptly set to the reference amount. it can. Therefore, according to the brake fluid pressure control device of the present invention, with respect to the brake device that executes both the pressure increase control using the fluid in the reservoir tank and the pressure reduction control using the free space in the reservoir tank, It is possible to always give a sufficient pressure increasing and depressurizing ability.

According to the second aspect of the present invention, by utilizing the brake pedal force acting on the brake pedal, it is possible to realize a mechanism for pressurizing the reservoir tank without adopting a complicated structure. Further, it is possible to prevent a sudden stroke change of the brake pedal when pressurizing the reservoir tank. Therefore, according to the present invention, it is possible to realize, with a simple configuration, a brake fluid pressure control device that can pressurize the reservoir tank without making the driver feel uncomfortable.

According to the third aspect of the invention, the fluid that has flowed into the wheel cylinder from the reservoir tank during execution of the pressure increase control flows into the reservoir tank from the wheel cylinder when the pressure increase control is completed. Therefore, according to the brake fluid pressure control device of the present invention, the fluid amount in the reservoir tank can be reliably returned to the initial value every time the pressure increase control is completed.

According to the invention described in claim 4, the increased amount of the brake fluid in the reservoir tank can be accurately fed to the master cylinder under pressure. Therefore, according to the brake fluid pressure control device of the present invention, the amount of brake fluid in the reservoir tank can be accurately adjusted to the reference value. Further, according to the present invention, the pump fluid can be pressure-fed from the reservoir tank to the master cylinder. Therefore, according to the brake fluid pressure control device of the present invention, the brake fluid in the reservoir tank can be reliably returned to the reference value even when the master cylinder pressure is increased.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of a first embodiment of the present invention.

FIG. 2 is a front sectional view of a master cylinder pressure pilot type relief valve used in the system of the first embodiment of the present invention.

FIG. 3 is a characteristic diagram showing an original position return characteristic of a reservoir tank used in the system of the first embodiment of the present invention.

FIG. 4 is a flowchart of an example of a control routine executed in the system of the first embodiment of the present invention.

FIG. 5 is a time chart for explaining an example of the operation of the system of the first exemplary embodiment of the present invention.

FIG. 6 is a system configuration diagram of a second embodiment of the present invention.

FIG. 7 is a system configuration diagram of a third embodiment of the present invention.

FIG. 8 is a flowchart of an example of a control routine executed in the system of the third embodiment of the present invention.

FIG. 9 is a system configuration diagram of a fourth embodiment of the present invention.

FIG. 10 is a flowchart of an example of a control routine executed in the system of the fourth embodiment of the present invention.

FIG. 11 is a flowchart of an example of a control routine executed in the system of the fifth embodiment of the present invention.

[Explanation of Codes] 10 Electronic Control Unit (ECU) 12 Master Cylinder 14 Brake Pedal 16,54 Reservoir Tank 24,26 First Solenoid 36,42 Second Solenoid 38,44 Third Solenoid 28,30 Wheel Cylinder 48 Pump Mechanism 50 Master cylinder pressure pilot type relief valve (PRV)

Claims (4)

[Claims] 1. A pressure increasing control for increasing a wheel cylinder pressure by supplying a brake fluid in a reservoir tank having an original position returning function to a wheel cylinder, and causing the brake fluid in the wheel cylinder to flow out into the reservoir tank. A brake fluid pressure control device for controlling a brake fluid pressure of a brake device for performing a pressure reduction control for reducing a wheel cylinder pressure, comprising: a pressurizing means for pressurizing a reservoir tank; A brake fluid pressure control device comprising: an atmosphere opening means for opening the tank to substantially atmospheric pressure. 2. The brake fluid pressure control device according to claim 1, wherein the pressurizing means includes a fluid generating mechanism for flowing out brake fluid according to a stroke amount of a brake pedal, the brake generating mechanism, and the reservoir tank. A brake fluid pressure control device comprising: a valve mechanism disposed between the valve mechanism and a pulse drive device that pulse-drives the valve mechanism. 3. The brake fluid pressure control device according to claim 1, wherein the pressurizing means includes a valve mechanism arranged between the wheel cylinder and the reservoir, and the valve mechanism when the pressure increasing control ends. A valve drive device for opening a mechanism, and a brake fluid pressure control device comprising: 4. A pressure increasing control for supplying a brake fluid in a reservoir tank to a wheel cylinder to increase a wheel cylinder pressure, and a brake fluid in the wheel cylinder flowing out into the reservoir tank to reduce the wheel cylinder pressure. In a brake fluid pressure control device for controlling a brake fluid pressure of a brake device for performing decompression control, a pressurizing means for pressurizing a reservoir tank, a fluid amount detecting means for detecting an amount of brake fluid in the reservoir tank, and the reservoir A pump mechanism for pumping up the brake fluid in the tank and pumping it to the master cylinder; and a pump drive means for driving the pump mechanism so that the brake fluid in the reservoir tank becomes a reference amount. Brake fluid pressure control device.