JPH1148936A - Wheel brake pressure controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize the pressure increasing/decreasing speed corresponding to the pedal speed even when the situation is beyond the assisting limit of a vacuum booster, to reduce the sound vibration of a solenoid valve during the vacuum adjustment, and to smoothly control the high brake pressure within an emergency brake region even with a small vacuum booster. SOLUTION: In wheel brake pressure control which utilizes a vacuum booster 1b, a master cylinder 1a, a pump 121 and a vacuum controlling solenoid 81, a pedal tread-in detector 103p, a pedal operating speed detecting means 110, and a vacuum switch 102 for detecting the assisting limit of the booster are provided. When the required pressure is beyond the assisting limit, the pump 121 is driven for increasing/decreasing the wheel brake pressure, so that either the vehicle deceleration Gd coincides with a target deceleration Go corresponding to the pedal tread-in or the pressure increasing/decreasing speed coincides with the pedal speed. In addition, the pressure decreasing speed is determined by selectively opening both or either one out of two flow passages 31A, 31B by means of solenoids 81A, 81B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake pressure generator for generating a brake fluid pressure corresponding to an applied operating force and applying it to a wheel brake. The present invention relates to a wheel brake pressure control device having a pump for applying a brake hydraulic pressure.

[0002]

2. Description of the Related Art Conventionally, this type of pump avoids a complete stop of wheel rotation (wheel lock) during braking by a driver (driver), for example, in order to ensure running stability and steering performance of a vehicle body. To reduce the wheel brake pressure, and then increase it so that the braking distance is as short as possible.
Further, anti-skid control (ABS control) that repeatedly reduces and increases pressure as necessary, wheel brake force distribution control between wheels to suppress the vehicle's side slip, head swing or butt swing during braking, or To compensate for insufficient brake fluid pressure for subsequent pressure increase by reducing the wheel brake pressure, such as traction slip control for suppressing wheel slip (acceleration slip) during vehicle acceleration, or The brake is provided for generating brake fluid pressure when there is no braking operation by the brake, and a solenoid valve for increasing or decreasing the wheel brake pressure is connected to the wheel brake.

[0003] A typical brake pressure generator is a brake pedal, a negative pressure booster which is connected to an input rod and which increases the force applied to the input rod and applies it to the output rod, and is driven by the output rod. The negative pressure booster has a diaphragm for separating a negative pressure chamber and a variable pressure chamber. The diaphragm is provided with a pressure difference between the negative pressure chamber and the variable pressure chamber, that is, an engine in-vehicle engine.
It is driven by the differential pressure between the negative pressure of the manifold and the pressure (in the range from the negative pressure to the atmospheric pressure) adjusted according to the amount of depression of the brake pedal. An output rod connected to the diaphragm drives the brake master cylinder, and the output pressure of the brake master cylinder is applied to the wheel brake.

[0004] At the time of braking that does not require steady-state computer intervention (wheel brake pressure control), the brake pressure generated by the brake master cylinder is applied to the wheel brake.
The load applied by the diaphragm of the negative pressure booster to the output rod is determined by the product of the area of the diaphragm and the above-mentioned differential pressure. Since both of them have limitations, the maximum value of the output load of the negative pressure booster is It is determined by the area (size of the negative pressure booster) and the negative pressure given by the engine on the vehicle. By increasing the maximum value of the output load of the negative pressure booster, a large braking force can be generated during sudden braking and the vehicle can be stopped suddenly, but the size of the negative pressure booster must be increased. Must. If the size of the negative pressure booster is small, the maximum value of the output load (maximum assisting force: assisting limit value) is small.

Japanese Patent Application Laid-Open No. 4-121260 discloses a hydraulic brake device that increases the wheel brake pressure at a high speed in response to the brake pedal depression speed. However, the wheel brake pressure is equal to or less than the output pressure of the brake master cylinder (FIGS. 2 and 5 of the publication),
Alternatively, the maximum brake pressure is independent of the brake operation speed and the pedaling force (FIG. 6 of the publication), and the output pressure of the brake master cylinder is substantially limited by the output load of the negative pressure booster. Therefore, even if the speed of increasing the wheel brake pressure corresponds to the pedal depression speed, the wheel brake pressure is substantially equal to or lower than the output pressure of the brake master cylinder corresponding to the maximum output load of the negative pressure booster. Above. Alternatively, when the brake operation speed exceeds a threshold value, the brake operation pressure is rapidly increased to the maximum brake pressure. However, even in a high braking force at the time of sudden braking, particularly in a high braking pressure region near or exceeding the assisting limit of the negative pressure booster, the braking pressure can be reduced in a reasonable and corresponding manner to the pedal operation. It is desired to provide a technology for smoothly controlling.

[0006] Japanese Patent Application Laid-Open No. 4-121260 discloses that
Japanese Patent Application No. 2-21053 discloses a solenoid valve for controlling the brake pressure of a brake pedal by detecting a brake pedal pressure by a pedal force sensor, and controlling a brake fluid pressure corresponding to the detected pedal force with a reservoir, a pump, an accumulator, and a wheel brake pressure. There is a description that a hydraulic brake device generated by a hydraulic pressure generating device provided with a wheel brake and supplied to a wheel brake is presented. Is presumed to have low emergency stop performance.

[0007] Even in a sudden braking region where a high braking force is required and a rapid increase in the braking pressure is required, it is necessary to control the braking pressure rationally and smoothly in response to the pedal operation. preferable.

[0008]

A pump for sucking the brake fluid at the output port of the brake master cylinder and discharging the sucked brake fluid to the wheel brakes is provided near the assist limit of the negative pressure booster. By driving the pump, a brake pressure higher than the assist limit value of the negative pressure booster can be applied to the wheel brake. However, this high pressure also needs to be adjusted according to the amount of depression of the brake pedal or its corresponding value. Therefore, an electromagnetic on-off valve is inserted between the wheel brake and the output port of the brake master cylinder, and the PW
While the M is energized and the pump is driven, this pressure control valve partially releases the pump discharge pressure to the output port (pump suction port) of the brake master cylinder to adjust the wheel brake pressure. Opening (flowing) / closing (blocking) of the electromagnetic on-off valve by energization causes large noise and vibration such as operating noise and oil hammer. Also, PWM pulse duty adjustment (pulse output processing) for changing the wheel brake pressure to a high or low speed in accordance with the depressing and returning speeds of the brake pedal or their corresponding values.
However, this complicates the wheel brake pressure control.

It is a first object of the present invention to control the brake pressure rationally and smoothly in response to an operation applied to the brake pressure generator even in a high braking force range. A second object of the present invention is to provide a wheel brake pressure control device having a large braking force even if the brake pressure generator generates a relatively low brake fluid pressure. It is a third object of the present invention to reduce the noise and vibration of the solenoid valve and to simplify the wheel brake pressure control.

[0010]

Means for Solving the Problems (1) The wheel brake pressure control device of the present invention generates a brake fluid pressure according to the applied operating force to generate a wheel brake (15).
Hydraulic pressure generating means (1) on the vehicle for applying to the wheel brake (151); and a brake hydraulic pressure higher than the brake hydraulic pressure generated by the hydraulic pressure generating means (1). Pumps (120, 121) on the vehicle for supplying air to the vehicle; said hydraulic pressure generating means (1) and wheel brakes
(151), a plurality of flow paths (31A, 31Bf) having different brake fluid flow resistances, and a selective flow path including connection control valves (81A, 81B) for opening and closing these flow paths. Channel (81A, 31A, 81B, 31B
f); the suction side flow path (LPL1) of the pump and the hydraulic pressure generating means
(1) a pressure control valve (83) for controlling the flow of the brake fluid between the output ports (82); and a drive / stop of the pump and a communication between the connection control valve and the pressure control valve. Adjustment control means (110) for controlling the flow.

In order to facilitate understanding, in the parentheses, corresponding elements or corresponding items of the embodiment shown in the drawings and described later or their symbols are added for reference.

According to this, since the pumps (120, 121) generate a discharge pressure higher than the brake hydraulic pressure generated by the hydraulic pressure generating means (1), the hydraulic pressure generating means (1) can generate the hydraulic pressure. Blaze
The wheel brake pressure can be increased to a brake fluid pressure higher than the brake fluid pressure. Therefore, the hydraulic pressure generating means (1)
May be of a small size with a relatively low maximum pressure.

When the pump is driven and the pressure control valve (83) is opened, the pump is driven through the pressure control valve (83) to generate hydraulic pressure.
The brake fluid is sucked from the output port (82) of (1) and the wheel brake
Discharge to the key, the discharge side flow path (HPL1) and the hydraulic pressure generation means (1)
Between the output port (82) and the selective passage (81A, 31A, 81B, 31B).
f), one or two or more of a plurality of flow paths (31A, 31Bf) having different brake fluid flow resistances therein are selected, and the discharge side flow path (HPL1) is output therefrom. Connected to the pump (82), the pump discharge flow is diverted to the pump inlet via the output port (82). The transformation speed of) changes. That is, the changing speed of the wheel brake pressure changes.

This will be specifically described based on embodiments described later. A connection control valve (81A) that opens and closes each of the channels (31A) and (31Bf) in the two sets of selective communication channels (81A and 31A) and (81B and 31Bf).
When all (81B) are closed (blocked), there is no shunt of the pump discharge flow to the suction port, and the wheel brake pressure rises rapidly at a speed corresponding to the pump drive speed (pressure increase). When the connection control valve (81B) that opens and closes the flow path (31Bf) with a large flow resistance is opened (flowed), a slight branch of the pump discharge flow to the suction port occurs, and the wheel brake pressure increases the pump discharge flow. The wheel brake pressure gradually decreases because it gradually escapes to the suction port (decompression).
1). Connection control valve that opens and closes the flow path (31Bf) with large flow resistance
(81A) closed (cut off) and flow path with low flow resistance (31A)
When the connection control valve (81A) that opens and closes the pump (81A) is opened (flowed), the branch pressure of the pump discharge flow to the suction port is slightly large, so the speed at which the wheel brake pressure releases from the pump discharge flow to the suction port is high. The wheel brake pressure immediately drops (decompression 2). And
When both flow paths (81A) and (81B) are open (flow), the amount of shunt of the pump discharge flow to the suction port increases, and the speed at which the wheel brake pressure releases the pump discharge flow to the suction port And the wheel brake pressure drops rapidly (decompression 3). Therefore, 2
When the flow paths (31A) and (31Bf) are used, the wheel brake pressure can be controlled at four speeds (pressure increase, pressure reduction 1, pressure reduction 2, and pressure reduction 3).

[0015] Which mode to use is determined by two connection control valves (8
1A) and (81B) are determined by the combination of open and closed.
The opening and closing of (81A) and (81B) may be switched only when the required mode is switched, and there is no frequent opening and closing like PWM control, and the solenoid valve for adjusting the brake pressure is not required. Sound vibration is reduced, and wheel brake pressure control is simplified.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION

(2) operating value detecting means (103p) for detecting an operating value (Pd) applied to the hydraulic pressure generating means (1); and means (110) for detecting a deceleration (Gd) of the vehicle. The adjustment control means (110) includes a target value (G) corresponding to the operation value (Pd).
The pump is driven to adjust the deceleration (Gd) to o), and the output port (82) of the hydraulic pressure generating means (1) is connected to the suction side flow path via the pressure control valve (83). In connection with the deceleration (Gd) and the target value (Go), if the deviation between the two is large in the direction in which the deceleration (Gd) exceeds the target value (Go), the flow resistance of the selected flow path is reduced. (Example 1; FIG. 7).

According to this, the wheel brake pressure is controlled so that the deceleration (Gd) corresponding to the operation value (Pd) is obtained, and the driver's operation on the hydraulic pressure generating means (1) is smoothly performed. Is followed by a wheel brake.

(3) An operation value detection means (103p) for detecting an operation value (Pd) applied to the hydraulic pressure generation means (1); and the adjustment control means (110) is provided with an operation value (Pd). In response to the change speed (dPS) of the (Pd), if the operation value (Pd) is high in the decreasing direction and the change speed (dPS) is high, the flow resistance of the selected flow passage is determined to be small (Example 2; FIG. ).

According to this, the wheel brake pressure changes at a speed corresponding to the change speed of the operation value (Pd), and the hydraulic pressure generating means
The wheel brake smoothly follows the driver's operation for (1).

(4) The brake fluid pressure is applied to the wheel brake (151).
Brake master cylinder (1a) for applying a brake pressure to the brake master cylinder (1a), a fluid pressure booster (1b) for driving the brake master cylinder by assisting an operation applied by a vehicle driver for wheel braking, and the fluid pressure booster (1b). The brake fluid is sucked from the brake master cylinder (1a) in order to apply a brake fluid pressure higher than the assisting limit of the booster (1b) to the wheel brake (151).
51) The hydraulic pressure source on the vehicle, including the pump (120, 121) that discharges to
(1, 120, 121); supply pressure adjusting means (81A, 31A, 81B, 31Bf, 83, 131, 132) between the hydraulic pressure source and the wheel brake for increasing and decreasing the wheel brake pressure; Operating value detecting means (1) for detecting the operating value (Pd) applied to the
03p); and supply pressure adjusting means (81
A, 31A, 81B, 31Bf, 83, 131, 132) in a wheel brake pressure control device comprising an adjustment control means (110); a means (110) for detecting the deceleration (Gd) of the vehicle; And a limit detecting means (102) for detecting whether the hydraulic pressure booster (1b) is less than the assisting limit or an assisting limit. A plurality of flow paths (31A, 31Br) interposed between the hydraulic pressure source and the wheel brakes and having different brake fluid flow resistances, and a connection control valve (81A) for opening and closing these flow paths. , 81B) (81A,
31A, 81B, 31Bf); and a pressure control valve (83) for controlling the flow of the brake fluid between the suction side flow path of the pump and the output port of the hydraulic pressure generating means. The adjustment control means (1
When the limit detection means (102) detects the assisting limit, the pump is driven to output the brake master cylinder output port (82) to the suction side flow path via the pressure control valve (83). ) And the target value (Go) corresponding to deceleration (Gd) and operation value (Pd)
In the direction where the deceleration (Gd) exceeds the target value (Go) and the deviation (Gd-Go) between them is large, the selected flow path (81A, 31A)
A, 81B, 31Bf), wherein the flow resistance of the wheel brake pressure control device is set to a small value (first embodiment).

According to this, when the hydraulic pressure booster reaches the assisting limit, the pump is driven and the wheel brake pressure is controlled so that the deceleration (Gd) corresponding to the operation value (Pd) is obtained. The wheel brake smoothly follows the driver's operation on the hydraulic pressure generating means (1) even in the brake pressure region exceeding the assist limit of the hydraulic pressure booster.

(5) Apply brake fluid pressure to wheel brake (151)
Brake master cylinder (1a) for applying a brake pressure to the brake master cylinder (1a), a hydraulic pressure booster (1b) for driving the brake master cylinder by assisting an operation applied by a vehicle driver for wheel braking, and A pump that sucks the brake fluid from the brake master cylinder and discharges it to the wheel brakes in order to apply brake fluid pressure higher than the booster assist limit to the wheel brakes.
Hydraulic pressure source (1,120,121) on the vehicle, including (120,121); supply pressure adjusting means (81A, 31A) between the hydraulic pressure source and the wheel brake for increasing and decreasing the wheel brake pressure. , 81B, 31Bf,
83, 131, 132); and an adjustment control means (110) for controlling the flow of the supply pressure adjustment means, wherein the hydraulic pressure booster (1b) is less than or less than the boosting limit. And a means (110) for detecting a rate of change (dPS) of an operation value (Pd) applied to the fluid pressure booster (1b). Adjusting means (81A, 31A, 81B, 31Bf, 83, 131, 132) are interposed between the hydraulic pressure source and the wheel brake, and a plurality of flow paths (31A, 31Br) having different brake fluid flow resistances. And, the selective communication channel (81A, 31A,
81B, 31Bf); and a pressure control valve (83) for controlling the flow of the brake fluid between the suction side flow path of the pump and the output port of the hydraulic pressure generating means. Control means (110)
When the limit detecting means (120) detects the assisting limit, the pump is driven to output the output port (82) of the brake master cylinder to the suction side flow path via the pressure control valve (83). In connection with the change speed of the operation value (dPS), the flow resistance of the selected flow passage is set to be small when the change value (dPS) in the decrease direction of the operation value is high, corresponding to the change speed of the operation value; Blaze
Pressure control device (Example 2).

According to this, when the hydraulic booster reaches the assisting limit, the pump is driven, and the wheel brake pressure changes at a speed corresponding to the change speed of the operation value (Pd), and the hydraulic pressure booster changes. −
Even in the brake pressure range exceeding the assisting limit of the star, the wheel brakes smoothly with respect to the driver's operation on the fluid pressure generating means (1).
Ki follows.

(6) The adjustment control means (110) controls the operating value (Pd) at a speed corresponding to the changing speed (dPS) until the limit detecting means (102) detects the assisting limit. When the detection means (102) detects the assistance limit, the pump (120, 12
1) is driven, and thereafter, when it is detected that the value is below the assisting limit, the driving of the pump is stopped. Since the driving of the pump is limited to a high brake pressure region exceeding the assist limit of the hydraulic booster, energy consumption by driving the pump is small.

Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

[0026]

【Example】

-First Embodiment- Fig. 1 shows a first embodiment of the present invention. The hydraulic pressure generator 1
It comprises a brake master cylinder 1a and a negative pressure booster 1b. When the brake pedal 103 is depressed beyond the amount of step play, the input shaft of the negative pressure booster 1b is pushed and the negative pressure booster is pressed.
The output shaft of the star 1b is connected to a negative pressure of an intake manifold of an on-vehicle engine (not shown) and an adjustment pressure (a value between the negative pressure and the atmospheric pressure) corresponding to the pushing amount of the input shaft. The operating shaft (piston rod) of the master cylinder 1a is pushed with a strong force proportional to the difference, whereby the wheels FR, FL, RR and R
Wheel cylinder (wheel brake) 15 disposed on L
A brake fluid pressure proportional to the output of the negative pressure booster 1b is applied to 1 to 154.

In the negative pressure booster 1b, a piston driven by a brake pedal 103 is hermetically fixed to the center of a substantially dish-shaped diaphragm. And a diaphragm, which is integrally and air-tightly fixed to the periphery of the shell. Cover
The boosting pressure chamber partitioned by the shell and the diaphragm is connected to an intake manifold (negative pressure) of an on-vehicle engine (not shown), and the transforming chamber partitioned by the base shell and the diaphragm is driven by the movement of the piston to increase the pressure. The pressure of the chamber or the atmospheric pressure is applied, and the pressure corresponds to the position of the piston.
The diaphragm is driven by the difference between the pressure in the variable pressure chamber and the pressure in the boost pressure chamber to drive the input rod of the brake master cylinder 1a. When the brake pedal is depressed above the piston position at which the pressure in the variable pressure chamber becomes the atmospheric pressure, the output of the negative pressure booster does not increase even if the depression amount increases. That is, the piston position at which the pressure in the variable pressure chamber becomes the atmospheric pressure is the assist limit position. This negative pressure booster 1b is disclosed in Japanese Patent Application No. 9-13344.
No. 9, the load exceeding the input load when reaching the assisting limit so that the booster input rod (brake pedal 103) can move (depressing direction) deeper than this assisting limit position. An elastic member that bends is interposed in a mechanism from the input rod to the output rod of the negative pressure booster.

FIG. 2 (a) shows that the brake pedal
Force applied to input rod of star 1b (Booster input load)
And the movement amount of the input rod in the pushing direction (the pushing amount of the input rod). When the input rod moves down by Se, the booster reaches the maximum assisting force (dead point: assisting limit),
After the assisting limit, the output rod is substantially driven by the force applied to the input rod (Se to S in FIG. 2A).
p). The elastic member starts to be substantially compressed from the displacement corresponding to the assisting limit, and the elastic member reaches the compression limit with the pushing movement amount Si. Thereafter, the output rod is driven substantially by the force applied to the input rod. The amount of pushing movement (Si-Sp) during compression of the elastic member, play allowance (ineffective stroke)
Is increasing. In this play allowance increase region, the increase of the booster input load (reaction force against the brake pedal) is ΔR
i, and thus the brake pedal reaction force increases even in the play allowance region, so that the driver does not substantially feel backlash.

Referring to FIG. 1 again, the base shell of the booster 1b is provided with a negative pressure switch 102 which switches in response to the pressure in the transformation chamber of the booster.
The negative pressure switch 102 switches from on (output L) to off (output H) when the pressure in the transformation chamber reaches the atmospheric pressure from the negative pressure, and when the pressure in the transformation chamber 15 decreases from the atmospheric pressure. The amount of decrease from the atmospheric pressure is a predetermined value (for example, 10 m
mHg), it has a falling hysteresis characteristic that switches from off (H) to on (L) when it reaches mHg. As shown in FIG. 2B, the negative pressure switch 102
Changes from L to H and vice versa.

Referring again to FIG. 1, pipes 82 and 92 to which the output ports of the brake master cylinder 1a communicate,
Between the wheel brakes 151 to 154, a pump 121,
122, reservoir (low pressure accumulator) 123, 12
4 and solenoid valves 81A, 81B, 83, 91A, 91B,
93, 131-138, relief valves 88, 98 and check valves 77A, 77B, 79A, 79B, 84-8.
6, 87A, 87B, 94 to 96, 97A, 97B are connected or inserted. The wheel FR indicates the front right wheel as viewed from the driver's seat, the wheel FL indicates the front left wheel, the wheel RR indicates the rear right wheel, and the wheel RL indicates the rear left wheel. As is apparent from FIG. Piping is configured.

One pipe 82 for supplying and discharging brake hydraulic pressure to the wheel brakes 151 and 154 of the front right wheel FR and the rear left wheel RL is connected to one output port of the master cylinder 1a. ing. A pair of solenoid on-off valves 81A / 81 is provided between the pipe 82 and the wheel brakes 151 and 154.
B and the check valves 77A, 87A / 77B, 87B are interposed in series, and the check valve 77A connected to the wheel brake 151 has a pressure increasing control valve 131 (an electromagnetic switching valve in this embodiment) in parallel with the wheel. A pressure increasing control valve 133 is connected in parallel with the check valve 87A connected to the brake 154. Wheel brakes 151 and 154 and reservoir 1
23, pressure reduction control valves 132 and 134 are interposed.

The first solenoid on-off valve 81A and the high pressure line HPL
There is an orifice 31A having a small flow resistance for narrowing the flow passage to a predetermined diameter (for example, 0.5 mm in diameter) between the second electromagnetic on-off valve 81B and the wheel brake 151. There is an orifice 31Bf that has a large flow resistance and is narrowed to a predetermined diameter (for example, a diameter of 0.3 mm).

Between the pipe 82 connected to the output port of the master cylinder 1a and the wheel brake 151, there is a series of a first electromagnetic on-off valve 81A, an orifice 31A having a small flow resistance, and a check valve 77A. When the first solenoid on-off valve 81A is open (flow), the first passage for returning the brake pressure of the wheel brake 151 to the conduit 82, the second solenoid on-off valve 81B and the check valve 77B And a series of orifices 31Bf having a large flow path resistance.
When B is open (flow), there is a second flow path for returning the brake pressure of the wheel brake 151 to the pipeline 82.

Pump 12 driven by electric motor 120
Check valve 8 between suction port 1 and reservoir 123
4, 85 are inserted in series, and both check valves 84, 85
A pressure control valve 83 (an electromagnetic switching valve in this embodiment) is interposed between the pipe 85 and the pipe 82. A check valve 76 is provided between the discharge port of the pump 121 and the high pressure line HPL1.
A damper 80 and an orifice 89 are interposed. The check valve 76 prevents backflow of the brake fluid from the high-pressure line HPL1 to the pump 121, and the damper 80 and the orifice 89 absorb high-frequency vibration (pulsation) of the discharge pressure applied to the high-pressure line HPL1 by the pump 121. (Smoothing). A check valve 8 is provided between the pipe 82 and the high-pressure line HPL1.
6, the relief valve 88 and the above-described electromagnetic on-off valve 81A,
The first and second communication passages each including 81B are connected in parallel.

There is no depression of the brake pedal 103 and acceleration slip (traction control for suppressing this)
When the wheel brake pressure distribution control for maintaining the vehicle body posture stably is not performed, the electromagnetic on-off valve 81
A, 81B, pressure control valve 83, pressure increase control valves 131, 13
3 and the pressure reduction control valves 132 and 134 are all off (non-energized), and as shown in FIG. 1, the first electromagnetic on-off valve 81A and the pressure increase control valves 131 and 133 are open (flow) and the second electromagnetic on-off Valve 81B, pressure control valve 83, and pressure reduction control valve 13
Reference numeral 2134 denotes a closed (interrupted) state. That is, the first solenoid on-off valve 81A and the pressure increase control valves 131 and 133 are normally open solenoid valves, and the second solenoid on-off valve 81B, the pressure control valve 83 and the pressure reduction control valves 132 and 134 are normally closed solenoid valves.

In this embodiment, the discharge pressure of the pump 121 is higher than the brake fluid pressure applied to the pipe 82 by the master cylinder 1a when the negative pressure booster 1b has reached the assisting limit. When the brake pedal 103 is depressed at or near the assist limit of the negative pressure booster 1b, an electric motor is applied to apply a pressure higher than the brake fluid pressure corresponding to the assist limit to the wheel brake. 120 is turned on (energized) to drive the pump 121, the first electromagnetic on-off valve 81A is turned on (energized) and closed (cuts off the flow path), and the pressure control valve 83 is turned on (energized) and opened (flow). Through the road). As a result, the pump 121 sucks in the brake fluid from the master cylinder 1a and discharges it to the high-pressure pipe HPL1 to turn it off (not energized).
To supply to the wheel brakes 151 and 154 through the pressure increasing control valves 131 and 133 which are opened (flow). In this state, the brake fluid at the output port of the brake master cylinder 1a is sucked by the pump 121 through the pressure control valve 83, and the pair of electromagnetic on-off valves 81A and 81B are connected to the pipe 82 and the high pressure pipe HP.
Since L1 is shut off, the hydraulic pressure in the high-pressure pipe HPL1 (discharge pressure of the pump) is applied to the wheel brake 151, and the hydraulic pressure in the brake master cylinder 1a decreases due to the suction of the pump. Brake pedal 1 via star 1b
03 can be pushed in the stepping direction.

When the solenoid on-off valves 81A and / or 81B are opened (flow), the hydraulic pressure of the wheel brake 151
2 (the brake master cylinder 1a), the brake pedal is lowered, and the brake pedal is pushed back in the release direction. Solenoid on-off valve 81
A and 81B are open (flow) or both are open (flow), and the wheel brake 15
4 can control the decompression rate.

The pump 121 is operated by a wheel brake or a brake.
The brake fluid is sucked out from the master cylinder 1a and discharged to the high pressure line HPL1. A relief valve 88 is provided to prevent an excessive rise in the pressure of the high-pressure line HPL1. When the hydraulic pressure of the high-pressure line HPL1 exceeds a set pressure, the brake of the high-pressure line HPL1 is passed through the relief valve 88. Liquid is in line 82
(Master cylinder 1a).

Another pipe 92 for supplying and discharging the brake fluid pressure to the wheel brakes 152 and 153 of the front left wheel FL and the rear right wheel RR is connected to another output port of the master cylinder 1a. It is connected to the. Between the pipe 92 and the wheel brakes 152 and 153, the pipe 82
Elements and fluid circuits which are interposed or added between the wheel brakes 151 and 154 are similarly connected. The description of these is the same as described above, and will not be repeated. For the sake of simplicity, the brake pressure control of the wheel brake 151 will be described below as a typical example. However, unless otherwise specified, the brake pressure of the other wheel brakes is also controlled. Of the wheel brake 151
Control is performed at substantially the same time as the key pressure control.

As described above, the wheel brake device shown in FIG. 1 uses the pair of electromagnetic on-off valves 81A and 8 together with the wheel brakes 154 to increase and decrease the pressure of the wheel brakes 151.
1B, and the pressure increase and pressure reduction of the wheel brake 151 alone can be performed by the pressure increase control valve 131 and the pressure reduction control valve 13.
2 can be performed.

In ABS control, traction control (acceleration slip control) and braking force distribution control, individual control of each wheel brake pressure is preferable. The wheel brake device shown in FIG. 1 drives the electric motor 120 (pumps 121 and 122) when the brake pressure control of any one of the wheel brakes 151 to 154 is required. On-off valve 81A, 8
1B and the pressure control valve 83 are closed (cut off), and the pressure increase and decrease pressures of the pressure increase control valve 131 and the pressure decrease control valve 132 are controlled to control the pressure of the wheel brake 151 and its pressure increase speed. And the step-down rate can be controlled.

In the embodiment of the present invention, as will be described later, the electronic control unit 110 controls the wheel brake pressure, that is, the ABS control, in order to suppress the increase in the wheel slip rate during wheel braking. When no brake control is required and the brake pedal is depressed beyond the assisting limit of the negative pressure booster 1b, the electric motor 120 (pumps 121, 1) is depressed.
22) to drive the wheel brake pressure to a pressure higher than the value corresponding to the assist limit. The ABS control has a higher priority than the steady control. In the ABS control, the electric motor 120 (pumps 121 and 122) is driven to close (cut off) the electromagnetic on-off valves 81A and 81B and the pressure control valve 83 to reduce the pressure. Under the duty control of the control valve 132 and the pressure increase control valve 131, the wheel brake 151 is reduced and pressure is increased, and when the wheel slip ratio is reduced, the pressure control valve 83 is turned on (open) to set the master cylinder 1a. And replenishes the high-pressure line HPL1 (wheel brake 151).

However, in the above-described steady control, the pressure control valve 8
3 is opened (flow), and the solenoid on-off valves 81A, 81B
When the wheel brake pressure is increased (increased) and decreased by closing (cutting off) both, one or both of the electromagnetic on-off valves 81A and 81B are opened (flow-through) (decompression 1, decompression 2, Decompression 3). Depressurization 1 with only solenoid on-off valve 81B open (flow)
In this case, the decrease in the wheel brake pressure is moderate. At the time of pressure reduction 2 in which only the electromagnetic on-off valve 81A is opened (flow), the wheel brake pressure drops slightly faster, and both electromagnetic on-off valves 81A
At the time of decompression 3 in which both A and 81B are opened (flow), the wheel brake pressure drops rapidly.

FIG. 3 shows the configuration of the electronic control unit 110. Electromagnetic on-off valves 81A and 81B, pressure control valve 83, electromagnetic on-off valves 91A and 91B, pressure control valve 93, increase / reduce valve 1
Numerals 31 to 138 are connected to the electronic control unit 110, and energization and non-energization of each solenoid coil are controlled. The electric motor 120 is also connected to the electronic control unit 110, and is thereby driven and controlled. Also, wheels FR, F
L, RR, and RL are wheel speed sensors 141 to 144, respectively.
Are connected to the electronic control unit 110, and the rotation speed of each wheel, that is, a wheel speed signal is input to the electronic control unit 110. The wheel speed sensors 141 to 144 are well-known electromagnetic induction type sensors including a toothed rotor that rotates with the rotation of each wheel and a pickup provided to face the tooth portion of the rotor. It outputs a pulse voltage having a frequency proportional to the speed. Note that a Hall IC, an optical sensor, or the like may be used instead.

A potentiometer 103p is connected to a pedal shaft integral with the brake pedal 103 as a stroke sensor for detecting the amount of pushing of the input rod of the booster 1b. This potentiometer 103p is An analog signal indicating the amount of depression of the brake pedal 103 (the rotation angle of the pedal 103) is given to the electronic control unit 110. The electronic control unit 110 converts the analog signal into a depression amount data and reads the pedal depression amount. Negative pressure switch 102
(L: below the assist limit) / OFF (H: above the assist limit) signal is also given to the electronic control unit 110.

FIG. 4 shows an outline of the wheel brake pressure control by the computer 111. The wheel brake pressure control (steps 2 to 13) shown in FIG. 4 is repeatedly executed at a substantially constant cycle Ts. When the ignition switch is turned on, initial settings are made in step 1 as a preliminary process in FIG. 4, and counters, timers, and the like are cleared. Further, an interrupt process executed for each pulse of the pulse voltage generated by the wheel speed sensors 141 to 144 is permitted. For example, when the wheel speed sensor 141 generates one pulse, the CPU 114 of the computer 111 executes an interrupt process in response thereto, and stores a count value of a clock pulse (clock pulse) in a pulse cycle register addressed to the front right wheel FR. Write and clear the clock pulse counter. The clock pulse counter always counts up the clock pulse while the interrupt processing is permitted. Therefore, the pulse cycle register addressed to the front right wheel FR stores the latest pulse voltage generated by the wheel speed sensor 141 in the pulse cycle register. Cycle (reciprocal of wheel speed)
Is always held. Wheel speed sensors 142-144
The same processing is performed by the CPU 114 for the voltage pulse generated by the wheel speed sensor. Therefore, after the interrupt processing is permitted, the data of the latest one cycle of the voltage pulse generated by the wheel speed sensors 141 to 144 is updated. It is always maintained in each pulse period register. In the "calculation of each wheel speed" (step 4) described later, C
The PU 114 calculates the wheel speed by multiplying the reciprocal of the data in the pulse cycle register by a coefficient (cycle / speed conversion coefficient).

Here, a counter, a timer, and the like used in the present embodiment will be generally described. First, a mode register and a flag register are provided as internal registers, and at least the following control modes are set in the former. That is, in addition to the pressure reducing mode, the pressure increasing mode, or the holding mode in which the brake fluid pressure in the wheel cylinders 151 to 154 is reduced, increased, or held, respectively, the pulse pressure increasing mode 1, 2, 2 3. Pulse decompression modes 1, 2, and 3 are set. Wheel brake pressure control mode (ABS control mode, steady control mode) and variable pressure mode
The contents of the code are as follows.

-ABS control mode- The contents are the same as those disclosed in Japanese Patent Application No. 8-319796. When the start area is reached, pressure reduction of the wheel brake of the wheel is started, and the pump 1
21 and 122, and then, depending on whether the combination of the slip ratio S and the wheel deceleration DWD is in the holding (holding), pressure increasing or pressure decreasing range, the wheel brake is held.
Pressure, increase or decrease pressure. During the ABS control, the pump drive and the electromagnetic on-off valves 81A and 81B are continuously closed (cut off), and the pressure control valve 83 is closed (cut off). 83 is opened (flow).

-Transformation mode in ABS control mode-Pressure reduction output 3 (pulse pressure reduction 3): solenoid on-off valves 81A, 81
B closed (cut off), pressure control valve 83 closed (cut off), and pressure increase control valve 131 closed (cut off), turn on (open) the pressure reducing control valve 132 at a high ON (open: flow = pressure reducing) duty. ) / Off (close) control (PWM energization), pressure reduction output 2 (pulse pressure reduction 2): ON / OFF control of pressure reduction control valve 132 at medium ON (pressure reduction) duty, pressure reduction output 1 (pulse pressure reduction 1) ): Low on (decompression) duty
ON / OFF control of the pressure reducing control valve 132 in the tee.

Hold (hold): solenoid on-off valves 81A, 8
1B closed (cut off), pressure control valve 83 closed (cut off), pressure increase control valve 131 closed (cut off), pressure reduction control valve 132 closed (cut off).

Pressure increase output 1 (pulse pressure increase 1): electromagnetic on-off valves 81A and 81B closed (cut off), pressure control valve 83 opened (flow)
On (open) / off (closed) control (PWM energization) and increase of the pressure increase control valve 131 at a low off (open: flow = pressure increase) duty with the pressure reduction control valve 132 closed (cut off) Pressure output 2 (pulse boost 2): solenoid on-off valves 81A, 81
ON / OFF control of the pressure increasing control valve 131 at a medium OFF (pressure increasing) duty, with B closed (cut off), the pressure control valve 83 opened (flow) and the pressure reducing control valve 132 closed (cut off). (PWM
Energized), boosted output 3 (pulse boosted 3): solenoid on-off valves 81A, 81
On / off control (PWM) of the pressure increasing control valve 131 at a high off (pressure increasing) duty with B closed (cut off), the pressure control valve 83 opened (flow) and the pressure reducing control valve 132 closed (cut off). Energized).

-Normal pressure control mode- Negative pressure switch 102 when not in ABS control
Is switched from L (less than the assisting limit) to H (more than the assisting limit), the pump is driven at a speed corresponding to the depressing speed of the brake pedal so far, and the pressure control valve 83 is turned on (open: flow through). ), The pressure increase control valve 131 is turned off (open: flow), and the pressure decrease control valve 132 is turned off (closed: shut off), corresponding to the deviation of the vehicle deceleration Gd from the target deceleration Go corresponding to the brake pedal depression amount Pd. To increase the wheel brake 151,
The pressure is reduced (FIGS. 7 and 11).

-Transformation mode in steady-state control mode-Pressure increase: The first solenoid on-off valve 81A is on (closed: shut off) and the second
Electromagnetic on-off valve 81B off (closed: shut off), motor 120 on, depressurization 1: first electromagnetic on-off valve 81A on (closed: off) and second electromagnetic on-off valve 81B on (open: flow), motor 120 off, depressurization 2: first electromagnetic on-off valve 81A off (open: flow) and second electromagnetic on-off valve 81B off (closed: shut off), motor 120 off, depressurization 3: first electromagnetic on-off valve 81A off ( Open: flow) and second solenoid on / off valve 81B on (open: flow), motor 120 off, hold: first on / off solenoid valve 81A on (closed: shut off) and second on / off solenoid valve 81B off (Closed: shut off), pressure increase control valve 1
31 on (closed: shut off), motor 120 off.

There are flags indicating each of the above-mentioned transformation modes. When any one of the flags is set, control for realizing the transformation mode corresponding to the set flag is performed. As a counter,
The system has at least a slow pressure reducing counter and a slow pressure increasing counter for ABS control. And the slow pressure increasing counter measures the continuous time of the slow pressure increasing mode (pressure increasing output 1) (the number of pressure increasing pulses generated while the pressure increasing output 1 continues).

Referring again to FIG. 4, when the initial setting is completed in step 1, the process from step 2 to step 13 is performed, and then the process returns to step 2. In step 2, T
Start the timer for the s period. In step 3, the analog signal of the potentiometer 103p is converted to digital data (data Pd for depressing the brake pedal) and written into a register, and the pressure detection signal of the negative pressure switch 102 is read. Pulse cycle registers (four to FR, to FL, to RR, and to RL) storing the cycle data of the pulses generated by the wheel speed sensors 141 to 144.
Is read and written into the input register. In step 4, the wheel speeds (peripheral speeds) VWFL, VWFR, VWRR and VWRL of each of the wheels FL, FR, RL and RR are calculated and written in the wheel speed registers. Each wheel deceleration DVW
FL, DVWFR, DVWRR and DVWRL (Positive values are deceleration,
Calculate the negative value of acceleration) and write it to the wheel deceleration register. Then, in step 6, the road surface friction coefficient μ is estimated.

In the "estimation of road friction coefficient μ" (step 6), the CPU 114 first checks whether the brake pedal depression amount Pd read in step 3 is in a small area, a medium area, or a multi area. Data indicating whether the region belongs to
Then, the deceleration of the maximum wheel speed is read from the wheel deceleration register, and it is checked whether the deceleration is in the small area, the medium area, or the large area. It generates data indicating whether it belongs. The area data of the brake pedal depression amount Pd and the area data of the deceleration
If the pedal depression amount is small & deceleration small, pedal depression amount is small & deceleration or pedal depression amount is large & deceleration is large, the road surface friction coefficient μ is estimated to be in the middle area, otherwise, When the pedal depression amount is small or medium & deceleration is large or medium, the road surface friction coefficient μ is estimated to be in a low region. Otherwise, the road surface friction coefficient μ is estimated to be in a high region, and data indicating the estimated region is obtained. Write to friction coefficient register.

Next, the CPU 114 calculates the vehicle speed VSO (n) in "estimated vehicle speed calculation" (step 7A).
Note that n of VSO (n) means the current calculated value, and n-1 appearing later means the calculated value of the previous time (before Ts).

In the "estimated vehicle speed calculation" (step 7A), firstly, if the road surface friction coefficient .mu. (High, medium or low) is high, the vehicle deceleration .alpha. It is defined as 0.6G for medium and 0.4G for low. Then, the vehicle acceleration αUP is determined to be 0.5G. Next, the highest wheel speed among the wheel speeds VWFL, VWFR, VWRR, VWRL is selected, and the current vehicle speed VWO (n-1) estimated from the previous calculated value VWO (n-1) and the deceleration αDN. −αDN ・
Ts is calculated, the current vehicle speed VWO (n-1) + αUP · Ts estimated from the previously calculated value VWO (n-1) and the acceleration αUP is calculated, and the intermediate value (average value) of these three is calculated. Calculate and set this as the current vehicle speed VWO (n).

Next, the CPU 114 calculates the vehicle body deceleration Gd (step 7B). In this, step 7A
Gd = VWO (n-1) -VWO (n) is calculated from the current vehicle speed VWO (n) calculated in step (1) and the previously calculated vehicle speed VWO (n-1). The positive value of the deceleration Gd is the deceleration, and the negative value is the acceleration.

Next, the CPU 114 calculates the estimated vehicle speed of each wheel section (step 8). Here, the deceleration αDN is calculated from the current value VWFR (n) and the previous value VWFR (n-1) of the front right wheel speed.
VWFR (n-
1) A value VWF obtained by adding the speed increase amount αUP · Ts during Ts at the acceleration αUP to −αDN · Ts and the previous value VWFR (n−1).
An intermediate value of three of R (n-1) + αUP · Ts is calculated, and this is set as a front right wheel portion estimated vehicle speed VSOFR (n). Similarly, the front left wheel portion estimated vehicle speed VSOFL (n), the present value VWRR (n) of the rear right wheel speed, and the rear left wheel portion estimated vehicle speed VSORL (n) are calculated.

Next, the CPU 114 calculates "front left wheel FL control calculation" (step 9FL) and "front right wheel FR control calculation" (step 9FL).
FR), “rear left wheel FL control operation” (9RL), and “rear right wheel FR control operation” (9RR), respectively. Since these contents are substantially the same except that the target wheel is different, the contents of “left front wheel FL control calculation” (9FL) will be described as a representative. In the "front left wheel FL control calculation" (9FL), first, it is checked whether the data of the flag register FRF is "1" (ABS control of the front left wheel FL is started).
If it is "0" (not started), the left front wheel FL
It is checked whether the ABS control of the wheel brake is necessary. Here, the slip ratio S of the left front wheel FL = [VSOFL (n) −VWFL (n)] × 100 / VSOFL (n)% is calculated, and the slip ratio S and the wheel deceleration DVWFL (n) are calculated as follows.
Check if it is in the control start area.

When the vehicle is in the control start area, the left front wheel FL
Set the transformation mode to reduced pressure and set the flag register FRF.
Write "1" to When the transformation mode is set in this manner, the "control output" of step 11 in FIG.
And outputs an instruction signal to a brake pressure circuit for reducing the wheel brake pressure. This is the start of “first decompression”.
In the "control output" (step 11), ABS control is being performed on any of the wheels (FRF =
If “1”), the CPU 114 causes the electric motor 120
A signal for driving the (pumps 121, 122) is given to the motor driver 118a. When the ABS control is started, it is checked whether the front left wheel portion estimated vehicle speed VSOFL (n) is equal to or less than a set value or the wheel slip ratio S is equal to or less than a set value. Is determined. Then, the transformation mode to the left front wheel FL is set to end, and "0" is written in the flag register FRF (flag register clear). When the end is set in this way, FIG.
In step 11 "control output", the wheel brake of the left front wheel FL is increased (continuous pressure increase: the output pressure of the master cylinder is applied to the wheel brake as it is, without the intervention of the computer). Output signal to the brake pressure circuit. When the ABS control is completed for all the wheels (FRF = “0”) in the “control output”, the CPU 114 causes the electric motor 120 (the pump 12
1, 122) to the motor driver 118a.
Give to.

If the ABS control of the front left wheel FL has been started and the end condition is not satisfied, the CPU 11
4 is a front left wheel F with reference to the data of the flag register.
It is checked whether the state is L "state before control initial pressure increase output", and if so, "control mode 1" is executed; otherwise, "control mode 2" is executed.

The above-mentioned “initial decompression” is started, and after Ts, the process proceeds to “front left wheel FL control calculation” (9FL) again, and AB
If the S control end condition is not satisfied, the CPU 114
Proceed to "control mode 1" and execute "control mode determination 1". Here, it is determined whether the slip ratio S and the wheel acceleration (a value obtained by multiplying the wheel deceleration DVWFL (n) by a negative sign) are in the pressure-reducing region, the holding region, or the pressure-increasing region. If it is determined that the pressure is reduced, the pressure is changed (output mode).
Is defined as “reduced pressure output 3”.

Thereafter, while the control mode determination 1 determines that the pressure is to be reduced, the output is determined to be "pressure reduction output 3", and the "pulse pressure reduction mode 3" relatively quickly causes the front left wheel. F
The wheel brake pressure of L decreases. When the wheel speed recovers due to the rapid pressure reduction and it is determined that the brake is maintained in the "control mode determination 1", the wheel brake is disconnected from the brake pressure circuit, and the brake fluid flows into and out of the wheel brake. Do not hold. If it is determined that the pressure is to be increased, the pressure increase output 2 is determined if it is not "low" by referring to the data (data indicating low, medium or high) of the friction coefficient register. The information "1" indicating that the output has been determined is written to the flag register IIF.

If it is "low", the transformation mode is determined to be "pressure increase output 1". Then, the information of the flag register is set to “the state after the control first-time pressure increase output”. This "pressure-increase output 1" means the above-mentioned "pulse pressure-increase mode 1." After that, since the state is after the control first pressure increase output, while the pressure increase is determined in the “control mode determination 2”, the output “pressure increase output 1” is determined, and the “pulse pressure increase mode” is determined. As a result, the wheel brake pressure of the front left wheel FL rises relatively slowly due to "-d1". The continuous time of this "pressure-increasing output 1" (the number of times that the pressure-increasing output 1 is determined to be continuous) is measured.

As described above, the “state after control initial pressure increase output”
After that, when it is determined that the pressure is reduced in the "control mode determination 2",
The output is determined as “pressure-decrease output 1”, and it is checked whether “pressure-increase output 3”, which is a pressure increase with a very high boosting speed, has been executed (IIF2 = 1). The brake pressure is excessively increased by the pressure increase by the pressure increase output 3, and it is considered that a rapid pressure decrease is required, and the information of the flag register is set to "the state before the control first pressure increase output". As a result, next time (after Ts), if it is determined that the pressure is to be reduced by the "control mode determination 1", the variable pressure mode is changed to the "pressure reduction output 3", and after the first pressure reduction is started, the "pressure increase" is started. After executing the "output 1", the CPU 114 determines that the pressure has been reduced by the "control mode determination 2" and sets the "pressure reduction output 1" to the variable pressure mode. (The number of times the pressure reduction output is determined to be 2 continuously) is measured, and when this continuous time exceeds the set value T1,
The information in the flag register is referred to as “state before control first pressure increase output”. As a result, the next time (after Ts), the “control mode
If it is determined that the pressure is reduced in the "mode determination 1", the pressure change mode is changed to "pressure reduction output 3", and the same control as the above-described first pressure reduction is performed.

If the continuous time exceeds the set value T2 while "pressure increase output 1" is continued while "pressure increase output 1" is continued in "control mode determination 2", the pressure change mode is set. Is changed to “pressure-increasing output 3”, and “1” is written into the flag register IIF2. Thereafter, when it is determined in the "control mode determination 2" that the pressure is to be reduced, the output is determined to be "a reduced pressure output 1", and "a pressure increase output 3", which is a pressure increase with a relatively high boosting speed, has been executed ( II
F2 = 1), the brake pressure is excessively increased by the "pressure increase output 3", and it is considered that a rapid pressure reduction is necessary, and the information of the flag register is set to "the state before the control first pressure increase output". . As a result, next time (after Ts), if it is determined that the pressure is reduced by the "control mode determination 1", the variable pressure mode is changed to the "pressure reduction output 3", and the same as that immediately after the start of the first pressure reduction described above. Perform control.

Referring back to FIG. The above "front left wheel FL
Control calculation ”(step 9FL),“ front right wheel FR control calculation ”(9FR),“ rear left wheel FL control calculation ”(9RL), and“ rear right wheel FR control calculation ”(9RR).
The PU 114 executes a “steady control operation” (9 AW).

FIG. 5 shows the contents of the "steady control operation" (9 AW). Here, first, the flag registers FRF, FL
It is checked whether the data of F, RRF and RLF are all "0" (ABS control is not performed for all wheels) (step 111). If so, it is checked whether the brake pedal depression amount Pd is within the braking effective area (the pedal 103 is depressed more than the play allowance PSa) (step 112). If so, it is checked whether the output of the negative pressure switch 102 is H (the negative pressure booster 1b is equal to or more than the assisting limit) (step 11).
3A). If the output of the negative pressure switch 102 is L (less than the assist limit), all the solenoid valves are turned off (de-energized) (step 113E), and the energization of the motor 120 is stopped (113).
F), the register FSW for storing the motor drive presence / absence information is cleared and its data is set to 0 (motor stopped) (step 113G), and "control mode determination 3" (step 1)
Perform 14).

FIG. 6 shows the contents of "control mode determination 3" (step 114). Here, first, the brake pedal depressing speed (dPS = Pd-previous Pd) is calculated (step 121A). In this calculation, Pd is the value read in step 3 this time, and Pd is the value read last time (Ts before this time).

Next, it is checked whether the stepping speed dPS is a positive value (stepping) (step 121B). If the stepping speed dPS is a positive value, the contents of dps2 are written into dps1 of the instantaneous speed register (step 122), and dps2 Is written (step 123), the content of dps4 is written into dps3 (step 124), and the current calculated value PS is written into the instantaneous speed register dps4 (step 1).
25). Then, the sum (integrated value) / Pd of the data of the instantaneous speed registers dps1 to dps4 is calculated (126). Next, the current calculated value dPS is stored in the maximum instantaneous speed register dPS.
Check whether the value of m is equal to or greater than dPSm (127).
a) If so, the current calculated value dPS is written to the maximum instantaneous speed register dPSm (127b).

The data dPSm of the maximum instantaneous speed register dPSm is set to threshold values (set values) dPS1, dPS2.
(Steps 127c and 129) and ΔPd
Is compared with threshold values (set values) ΣPd1 and ΣPd2 (steps 128, 130 and 131), and according to the value of the maximum stepping speed dPSm and the integrated value ΣPd, as shown in FIG. The energization duty command value Md of 120 is set (steps 132A to 134A). The energization duty command value Md specifies the ratio (%) of the energization time in one cycle of the PWM energization of the motor 120 to one cycle.

As shown in FIG. 9, the maximum stepping speed dPSm
Is high, the energization duty command value Md is set to a high value,
If the value of the integrated value ΣPd is large, the energization duty command value Md is set to a high value. In the process of increasing the wheel brake pressure by one depression of the brake pedal 103, if the stepping speed is high as shown in FIG. 8, for example, the dPSm is large and the integrated value ΔPd is large, so the energization duty command value Md Is set to, for example, 100%. When the stepping speed is medium as shown in FIG. 8, the dPSm and the integrated value ΔPd are both medium, so that the energization duty command value Md is, for example, 80.
% And when the stepping speed is low as shown in FIG.
Since Sm is small and the integrated value ΔPd is small, the energization duty command value Md is set to, for example, 60%.

While the output of the negative pressure switch 102 is L (less than the assisting limit), the depressing speed of the brake pedal 103 is calculated in this way, and the energization duty command value M is correspondingly calculated.
Set d.

When the output of the negative pressure switch 102 switches from L to H (more than the assisting limit), the motor 120 starts energization (pump driving) with the energization duty Md set as described above, and the register Write 1 (during pump drive) to the FSW (steps 113B to 113D). Then, a target deceleration Go corresponding to the brake pedal depression amount Pd is calculated (step 115).

In the internal memory of the CPU 114, there is shown a data (dot-dash line) representing the relationship between the brake pedal depression amount Pd (horizontal axis) and the target deceleration Go (right vertical axis), which is indicated by a one-dot chain line in FIG. In step 115, this data
The target deceleration Go corresponding to the brake pedal depression amount Pd read in step 3 is read from the table.

FIG. 10 shows the relationship (solid line) between the stepping amount Pd (horizontal axis) and the load (left vertical axis) applied to the input rod 4 of the booster 1b, and the wheel brake by the electronic control unit 110. Stepping amount Pd when key pressure control is not performed
The relationship (dotted line) between (horizontal axis) and the vehicle body deceleration Gd is shown.

The pushing amount of the input rod of the booster 1b is Se.
At this time, the booster 1b reaches the assisting limit and the booster 1b
, The rod driving force of the master cylinder due to the pressure difference between the atmospheric pressure and the negative pressure (the engine manifold pressure) becomes the maximum value (the highest assisting force). Assuming that the booster input load at this time is Fbm, the brake pedal depression amount Pd is a value PS corresponding to the depression amount Se of the input rod of the booster 1b.
e, the booster input load is Fbm as shown in FIG.
Becomes The output load of the output rod of the booster 1b is small and the assisting function of the booster 1b is saturated until the brake pedal depression amount Pd exceeds Pse and reaches the depression limit PSi.

However, in this embodiment, the pump 121,
The brake pressing force by the discharge pressure of 122 is larger than the maximum value of the output load of the booster (the boosting limit corresponding to Fbm), and the deceleration of the vehicle body caused by this increases the maximum pedaling amount Pd of the brake pedal. Target deceleration Go corresponding to the value PSi
m is determined. The target deceleration Go is calculated as shown in FIG.
As shown in Fig. 7, after the boosting limit (Fbm), the deceleration is set to be higher than the vehicle deceleration (approximately Gds) when the booster output is the maximum assisting force Fbm.
A high deceleration (wheel brake pressure) is determined over the pedal depression amounts PSe to PSi corresponding to the wheel brake pressure higher than the boosting limit of the star 1b.

After calculating the target deceleration Go as described above, the CPU 114 proceeds to "control mode determination 4" (step 11).
Perform 6). This is shown in FIG. In this case, the vehicle body deceleration Gd calculated in step 7B (FIG. 4) is compared with the target deceleration Go (steps 151 to 15).
4), as shown in FIG.
Hold, reduced pressure 1, reduced pressure 2, reduced pressure 3) are determined (steps 155 to 161).

That is, if dG = Go-Gd is positive and exceeds the set value h, "pressure increase" and the transformation mode are set (steps 151 and 155). Otherwise, the absolute value of dG = Go-Gd is set. If the value is not more than h, a hold is set (step 159). A value r in which the vehicle deceleration Gd is larger than the target value Go (dG = Go−Gd is negative) and the deviation between the two is large.
If the time exceeds s, “decompression 3” is set (step 1).
53, 156) Otherwise, if the vehicle deceleration Gd is larger than the target value Go, but the deviation between them is less than rs and exceeds a smaller value r, "decompression 2" is set (step 154). 157), otherwise, the vehicle deceleration G
d is larger than the target value Go, but the deviation between them is less than r or less h
Is exceeded, "decompression 1" is set (step 1).
54, 158).

When the transformation mode is set as described above, FIG.
In step 111, "control output", the control mode and the transformation mode determined as described above are executed. CPU1
14 is the energization duty command value M set as described above.
d, the electric motor 120 is energized with a duty Md.
To energize. If the pedal depressing speed until the negative pressure booster 1b reaches the assisting limit is high, the energizing duty M
Since d is high and the output torque of the electric motor 120 is high, the pumps 121 and 122 are driven at a high speed, and when the "pressure increase" is set, the brake pressure applied to the wheel brakes increases at a high speed. However, if the pedal depression speed until reaching the assist limit is low, the energization duty Md is low as described above,
Since the output torque of the electric motor 120 is low, the pump 12
1, 122 are driven at a low speed, and the rising speed of the brake pressure applied to the wheel brake when the above "pressure increase" is set is low.

By the way, when Gd <Gds and the stepping speed dPS is a negative value (release of the pedal depression: return) at step 121B of FIG. 6, step 1 of FIG.
At 21C, the maximum instantaneous value register dPSm is cleared, and at step 135, the data of the register FSW becomes "1" (during pump driving; immediately after boosting near or above the boosting limit of the negative pressure booster). ) Is checked (step 135). If the data of the register FSW is "1", it is checked whether the stepping speed dPS (negative value) is equal to or less than the third set value nPS3 (negative value) (the pedal return speed is high) (step 136). In this case, the transformation mode is set to "decompression 3" (139). If it is larger than the third set value nPS3, it is checked whether it is equal to or less than the second set value nPS2 (the pedal return speed is medium speed) (step 137). If so, the transformation mode is set to "decompression 2" (step 14).
0). If it is larger than the second set value nPS2, it is checked whether it is equal to or less than the first set value nPS1 (the pedal return speed is low) (step 138), and if so, the transformation mode is set to "decompression 2" (step 141). . First set value n
If it is larger than PS1, the transformation mode is set to "hold" (142) and the register FSW is cleared (143).

When the control mode and the transformation mode are set in this way, the control mode and the transformation mode determined as described above are executed at the "control output" of step 11 in FIG. , Due to the strong depression of the brake pedal 103,
When the negative pressure booster 1b exceeds the assisting limit, the pump 12
1, 122 (electric motor 120) is driven, and the wheel brake pressure is increased and reduced so that the deceleration of the vehicle becomes the value Go corresponding to the depressed stroke of the brake pedal.

In the above-described control mode in which the negative pressure booster 1b is equal to or higher than the assisting limit, the pumps 121 and 122 are driven at a speed corresponding to the pedal depression speed until the assisting limit is reached, and the pressure control valve is controlled. 83 is on (open: flow), pressure increase control valve 131 is off (open: flow), and pressure reduction control valve 132
Is off (closed: shut off). Then, the control proceeds as follows.

(1) When “pressure increase” in step 155 (FIG. 7) is set, that is, when the vehicle deceleration Gd is lower than the target deceleration Go and the difference between the two exceeds h,
The first solenoid on-off valve 81A and the second solenoid on-off valve 81B are both closed (cut off), the pump sucks the brake pressure from the brake master cylinder 1a through the pressure control valve 83, and the wheel brakes through the pressure increase control valve 131. Discharge to the key 151; As a result, the pressure of the wheel brake 151 increases at a speed corresponding to the pedal depression speed until the assist limit is reached. Since the suction pressure of the pump is applied to the brake master cylinder 1a, the reaction force corresponding to the pedaling force applied to the brake pedal 103 is reduced by the load corresponding to the pedal depression speed until reaching the assisting limit, and the pedal 103 moves in the pushing direction. I do.

The change in the target deceleration Go (the dashed line in FIG. 10) with respect to the change in the pedal depression amount Pd decreases with the increase in the pedal depression amount Pd. As the deceleration increases linearly,
Is continued, the vehicle deceleration Gd becomes higher than the target deceleration Go.

(2) Vehicle deceleration Gd-target deceleration Go is h
Is exceeded, "pressure reduction 1" is set, the first solenoid on-off valve 81A is closed (cut off), but the second solenoid on-off valve 81B is opened (flow), and the pressure of the high pressure pipe HPL1 is reduced to the master cylinder 1a. Is discharged with relatively high flow resistance to the pipe 82 (the suction port of the pump) to which the output port of the vehicle communicates, and the wheel brake pressure (the pressure of the high pressure pipe HPL1) gradually decreases, and the brake pedal The pedaling opposition reaction force applied to 103 gradually increases. Here, if the driver's pedal depression force is increased, the operation shifts to the above (1), but if the depression force is not enhanced, or if the driver's depression force is reduced, the pedal 103 moves in the releasing direction with an increase in the depression force opposing reaction force. Target deceleration G
o falls.

(3) Vehicle deceleration Gd-target deceleration Go is r
Is exceeded, "pressure reduction 2" is set, the first solenoid on-off valve 81A opens (flows), the second solenoid on-off valve 81B closes (cuts off), and the pressure of the high-pressure pipe HPL1 is reduced by the pressure of the master cylinder 1a. A relatively low flow resistance is discharged to the pipe 82 to which the output port communicates, and the wheel brake pressure (high pressure pipe HPL
1) decreases relatively quickly, and the brake pedal 10
The pedaling opposition reaction force applied to No. 3 rises at a relatively high speed. If the driver's pedal pressure increases,
Turning to (2), when the pedaling force of the driver is reduced, the pedal 103 moves in the releasing direction at a relatively high speed with an increase in the pedaling force opposing reaction force, and the target deceleration Go decreases. (4) When the vehicle deceleration Gd-the target deceleration Go exceeds rs, "decompression 3" is set, and both the first solenoid on-off valve 81A and the second solenoid on-off valve 81B open (flow), and the high-pressure pipe The pressure of the HPL 1 is released with a low flow resistance to the pipe 82 to which the output port of the master cylinder 1 a communicates, and the wheel brake pressure (the pressure of the high-pressure pipe HPL 1) decreases rapidly, and the brake pedal 103 The applied opposing reaction force increases rapidly. Here, if the driver's pedaling force is increased, the process goes to the above (3). However, if the driver's pedaling force is reduced, the target deceleration Go of the pedal 103 is rapidly decreased with an increase in the pedaling force opposing reaction force.

When the negative pressure booster 1b reaches the assisting limit due to the driver's strong depression of the brake pedal 103, the above-mentioned (1) is reached, and the above-mentioned condition is maintained while the depression movement is continued.
While (1) is maintained and the stepping movement is stopped (hold), the above (1) and (2) are repeated.When the driver returns the brake pedal, the above (2), (3) or The control of (4) is performed in this order. When the pedal release speed is high, the period during which the above (2) and (3) are executed is short, and (4) is executed quickly. When the pedal release speed is low, the above (2) and (3) are executed and the possibility of proceeding to (4) is low.

According to the above (2), (3) or (4), the negative pressure booster 1b returns below the assisting limit, and then the pressure in the transformation chamber 15 drops below the atmospheric pressure by a set value (10 mmHg). At this time, the output of the pressure switch 102 is switched from H to L, and in response to this, the microcomputer 111 proceeds from step 113A to step 113E in FIG. 5 to turn off all the solenoid valves (see FIG. 1). (Step 113F) and the pump drive is stopped (step 113F), so that the wheel brake pressure is determined by the assisting force of the negative pressure booster 1b. ”(Step 114), when it is detected in Step 121B shown in FIG. 6 that the pedal is returning, the return speed dP
S is fast (dPS ≦ nPS3), relatively fast (dPS ≦ nPS2), or slow (dP ≦ nPS2)
Check whether S ≦ nPS1) (Step 13)
6 to 138), "decompression 3" is set when the speed is rapid, "decompression 2" is set when the speed is relatively rapid, and "decompression 1" is set when the speed is slow, and the return speed is substantially 0. , "Hold" is set (steps 139 to 142). Accordingly, the wheel brake pressure returns to the brake master cylinder 1a at a higher speed corresponding to the return speed of the brake pedal of the driver as the speed is higher.

When the ABS control (9FL to 9RR) or the steady control (9AW) is completed, an OFF instruction is output to the motor driver and the solenoid drivers 118a to 118m, and each timer of the holding timer, the pressure reducing timer, and the pressure increasing timer is output. Is cleared, and the pulse pressure increase counter, the pulse pressure increase flag, and the rapid pressure decrease flag are cleared (step 12).

Then, it is checked whether or not the timer Ts has timed out (step 13), and an abnormality check is performed until the time is over (step 14). When an abnormality is detected, the brake pressure control is released and an alarm is generated (steps 15 and 16).

The above-described ABS control (9FL to 9R)
R) is started when the wheel deceleration and the wheel slip ratio of at least one wheel have entered the antilock control start area, the operation is performed until the brake pedal is released, and ends when the brake pedal is released. I do. During the ABS control, the data of the register FRF, FLF, RRF or RLF is "1". When the ABS control is not being performed, the data in the registers FRF, FLF, RRF and RLF is "0", and the steady control (9AW) is performed while the brake pedal is being depressed at this time. ABS
The fact that control is not performed is that (1) the road surface is high μ, the wheel slip ratio is low, and wheel lock due to sudden braking is unlikely to occur (the vehicle body braking effect is high), or (2) braking This means that the depression amount of the key pedal is small and the vehicle deceleration (wheel deceleration) is low.

In the case of the above (1), when the driver depresses the brake pedal 103 more than the boosting limit corresponding amount PSe of the booster 1b, sudden braking is performed by the above-described steady control (9AW). The brake pressure higher than the brake pressure possible in 1b is applied to the wheel brake, and the vehicle body is suddenly braked.
In addition, in the prior art, the upper limit region P in which the increase in the wheel brake pressure cannot be substantially expected with respect to the increase in the brake pedal depression amount.
From Se to PSi, the wheel brake pressure rapidly increases in proportion to the increase in the brake pedal depression amount, and emergency braking is required. Is effectively emitted. The sudden increase in the wheel brake pressure of this rapid brake is also caused by the booster 1
b is a speed corresponding to the pedal depressing speed until the maximum assist output is obtained, and the wheel brake pressure changes smoothly in accordance with the pedal operation (stepping amount and stepping speed) of the driver. When the brake is released immediately after the sudden braking, the wheel brake pressure is reduced at a deceleration corresponding to the pedal return speed, and the response to the release of the brake pressure is high.

The case (2) above is a gentle braking region in which the degree of urgency in driving the vehicle is low. In this region, the change in the wheel brake pressure due to the output of the booster 1b interlocked with the pedal operation causes a fluctuation. -Efficient lighting is achieved according to the depression amount and the depression speed of the key pedal 103.

Now, assuming that the driver depresses the brake pedal 103 during traveling of the vehicle and the pedal depression amount Pd is equal to or greater than the assist limit (sudden brake), the wheels by the "steady control calculation" (9AW) By the brake pressure control, the wheel brake pressure is increased so that the vehicle body deceleration Gd rises to the target deceleration Go shown in FIG. 10 at a speed proportional to the stepping speed in accordance with the pedal depression amount Pd. Controlled. During this brake pressure control, the deceleration of each wheel is calculated by “calculation of wheel deceleration of each wheel” 5, μ of the road surface is estimated by “estimation of friction coefficient μ of road surface” 6, and “estimated vehicle speed calculation” 7A, the vehicle speed is estimated and calculated, and the "estimated vehicle deceleration Gd calculation" 7B is estimated and calculated. Then, in each wheel control calculation 9FL to 9RR, each wheel slip ratio S is calculated,
It is checked whether the slip ratio and the wheel deceleration of each wheel are in a region where the ABS control is to be started (excessive slip ratio region), and when the wheel enters the ABS control start region (that is, the wheel slip ratio becomes excessive due to sudden braking). ), The ABS control is started. That is, the wheel brake pressure control is switched from the steady control 9AW to the ABS control.

The basic data for the ABS control is generated in "Estimation of the road friction coefficient μ" 6, in which the brake pedal depression amount Pd is included in the parameter, and this range corresponds to the booster 1b. There is a pedal stroke (PSi-PSe) exceeding the boosting limit of the booster up to PSi which is larger than the depression amount PSe corresponding to the key touch point, and the ABS control extends to a range exceeding the boosting limit. When the steady-state control 9AW is switched to the ABS control, when the brake pedal depression amount Pd is in a region (PSi-PSe) exceeding the maximum assist limit for the booster (when the vehicle body deceleration is extremely high). ) Also has steady control 9
Consistent (continuous) with wheel brake pressure control by AW
The ABS control is started, and the continuity of the wheel brake pressure control is high. The same applies when switching from the ABS control to the steady control 9AW.

-Second Embodiment- In the above-described first embodiment, the negative pressure valve in the steady control 9AW is used.
In the wheel brake pressure control when the star 1b is equal to or larger than the assisting limit, the target value Go of the vehicle deceleration corresponding to the depression amount of the brake pedal 103 and the actual vehicle deceleration Gd (however, the estimation calculated in step 7B) Value), "Pressure increase",
"Hold", "Decompression 1", "Decompression 2" or "Decompression 3"
However, in the second embodiment, the brake pedal 10
"Control mode judgment" corresponding to the operation speed dPS of 3
At (step 116), "pressure increase", "hold",
"Decompression 1", "Decompression 2" or "Decompression 3" is determined.

In order to execute this, it is necessary to calculate the operation speed dPS before the "control mode determination" (step 116). Therefore, in the second embodiment, the "steady control calculation" (9 AW) ), "Calculation of stepping speed dPS" (step 121A) is executed as shown in FIG. In "control mode determination 3" (step 114), "calculation of stepping speed dPS" (step 121A) is omitted as shown in FIG. In the "control mode determination" (step 116) which is executed when the negative pressure booster 1b is equal to or larger than the assisting limit, the variable pressure mode is set as shown in FIG.

That is, the moving speed dPS of the pedal 103
When the pressure is positive (stepping direction) and exceeds the set value Sh, "pressure increase" is set (steps 161 and 16).
5) When the absolute value of the pedal movement speed dPS is equal to or less than Sh, the vehicle deceleration Gd is adjusted to the target deceleration Go corresponding to the pedal depression amount, as in steps 151 to 159 in FIG. 7 of the first embodiment. , Pressure increase, hold or pressure reduction 1
3 is set (steps 162, 151 to 159). When the pedal movement speed dPS is negative (release direction) and the absolute value is smaller than the negative value set value Srs (release speed is rapid), "decompression 3" is set (steps 163, 16).
6) When the pedal movement speed dPS is negative (release direction) and the absolute value is smaller than the medium negative set value Sr and is equal to or greater than Srs (release speed is relatively fast), “decompression 2” is set ( Steps 164 and 167), pedal movement speed dP
If S is negative (release direction) and the absolute value is smaller than the set value Sh and equal to or smaller than Sr (release speed is slow), "decompression 1" is set (168).

As described above, while the pedal 103 is moving in the depressing direction, the wheel brake 151 is generated by the "pressure increase".
Increases at a speed corresponding to the pedal depression speed until the assisting limit is reached. When the pedal 103 is released, the wheel brake pressure decreases at a speed corresponding to the release speed.

When the negative pressure booster 1b reaches the assisting limit due to a strong depression of the brake pedal 103 by the driver, the wheel brake pressure is maintained increased while the depression movement is continued, and the depression movement is performed. While the vehicle is stopped (hold), the wheel brake pressure is increased and decreased to match the vehicle deceleration Gd with the target deceleration Go corresponding to the depression amount of the pedal, and the driver releases the brake pedal. , The wheel brake pressure is reduced at a speed corresponding to the return speed.

The hardware configuration of the second embodiment and other functions of the changed functions are the same as those of the first embodiment.

In the embodiment described above, the operation amount detection means (103p) for detecting the operation value applied to the fluid pressure booster (1b) serves as the operation amount detection means (103p) for the depression amount Pd of the brake pedal 103.
As shown by the solid line in FIG. 10, a potentiometer 103p for detecting the wheel brake pressure control range is provided between the brake pedal depression amount Pd and the booster input load. Since there is a one-to-one relationship in the stepping amount Pd,
Instead of the potentiometer 103p, a load sensor for detecting a pedaling force may be used. That is, load detection may be performed instead of stroke detection. In this case,
A data table storing data representing the relationship between the pedal depression amount Pd and the target deceleration Go is stored in a table containing the pedaling force and the target deceleration G.
Let us express the relationship of o. As the treading force sensor, a sensor used for load detection, such as a strain gauge or a pressure-sensitive sensor, may be used.

In the embodiment described above,
The deceleration of the vehicle body is obtained by the CPU 114 of the electronic control unit 110 estimating and calculating the vehicle body speed from the detected rotation speed of each wheel and calculating the differential value of the calculated vehicle body speed. An acceleration sensor for detecting acceleration and deceleration may be provided to detect the vehicle body deceleration. In any case, when the deceleration (wheel brake pressure) becomes excessive with respect to the road surface condition and the wheel slip increases, the above-described ABS control is started, so that the wheel lock is avoided and the steering stability is improved. Secured.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a first exemplary embodiment of the present invention.

2 (a) is a graph showing a relationship between an input rod pushing amount and an input load of the negative pressure booster 1b shown in FIG. 1, and FIG. 2 (b) is a negative pressure booster 1b shown in FIG. 4 is a time chart showing a change in the pressure of the transformer chamber and a change in the output signal of the negative pressure switch 102.

FIG. 3 is a block diagram illustrating a schematic configuration of an electronic control device 110 illustrated in FIG.

FIG. 4 is a flowchart showing an outline of wheel brake pressure control of the microcomputer 111 shown in FIG. 3;

FIG. 5 is a flowchart showing the contents of a "steady control operation" 9AW shown in FIG.

FIG. 6 is a flowchart showing the contents of "control mode determination 3" 114 shown in FIG.

FIG. 7 is a flowchart showing the contents of "control mode determination 4" 116 shown in FIG.

FIG. 8 is a graph showing three examples of the depression speed of the brake pedal 103 shown in FIG.

9 shows the relationship between the stepping speed dPS of the brake pedal 103 and the stepping amount integrated value ΔPd, and the value of the motor energization duty Md determined by the “control mode determination 3” 114 shown in FIG. It is a graph shown.

10 is a graph showing the relationship between the depression amount Pd of the brake pedal 103 shown in FIG. 1 and the input load of the brake booster 1b.

11 is a graph showing an area of a pressure change mode determined by a CPU 114 in correspondence with a vehicle deceleration Gd and a target deceleration Go in "control mode determination 4" 116 in FIG.

FIG. 12 is a flowchart showing the contents of “steady-state control calculation” 9AW performed in the second embodiment.

FIG. 13 shows “control mode determination 3” 114 shown in FIG.
Is a flowchart showing the contents of the above.

FIG. 14 shows “control mode determination 4” 116 shown in FIG.
Is a flowchart showing the contents of the above.

[Explanation of symbols]

1: hydraulic pressure source 1a: master cylinder 1b: booster 80, 90: damper 89, 99: orifice 81A, 81B, 91
A, 91B: solenoid on-off valves 83, 93: pressure control valve 102: negative pressure switch 103: brake pedal 103p: potentiometer 110: electronic control unit 111: microcomputer 112: input port 113: output Port 114: CPU 115: ROM 116: RAM 117a to 17e: Amplifier circuit 118a to 18o: Driver 120: Electric motor 121, 22: Pump 123, 124: Reservoir 131, 133, 135, 137: Increase Pressure control valves 132, 134, 136, 138: pressure reduction control valves 141 to 144: wheel speed sensors 151 to 154: wheel brakes FR: front right wheel FL: front left wheel RR: rear right wheel RL: rear left wheel

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akihide Kamiya 2-1-1 Asahi-cho, Kariya-shi, Aichi Prefecture Inside Ishin Seiki Co., Ltd. (72) Inventor Shigeru Sakamoto 1-Toyota-cho, Toyota-shi, Aichi Prefecture Toyota Auto (72) Inventor Koichi Sawada 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation

Claims (6)

[Claims] 1. A hydraulic pressure generating means on a vehicle for generating a brake hydraulic pressure according to an applied operating force and applying the same to a wheel brake; a brake hydraulic pressure generated by the hydraulic pressure generating means A pump on the vehicle for applying a higher brake fluid pressure to the wheel brake; interposed between the fluid pressure generating means and the wheel brake, and having a different brake fluid flow resistance. A plurality of flow paths and a selective flow path including a connection control valve for opening and closing these flow paths; a flow of a brake fluid between a suction side flow path of the pump and an output port of the hydraulic pressure generating means; A wheel brake pressure control device comprising: a pressure control valve for controlling a flow; and an adjustment control means for controlling driving / stopping of the pump and flow of the connection control valve and the pressure control valve. 2. The system according to claim 1, further comprising: an operation value detecting means for detecting an operation value applied to the hydraulic pressure generating means; and a means for detecting a deceleration of the vehicle. The pump is driven to adjust the deceleration to the desired value, and the output port of the hydraulic pressure generating means is connected to the suction side flow path via the pressure control valve, and the deceleration and the target value are adjusted. 2. The wheel brake pressure control device according to claim 1, wherein the flow resistance of the selected flow passage is determined to be small when the deviation between the two is large in the direction in which the deceleration exceeds the target value. 3. An operation value detecting means for detecting an operation value applied to the hydraulic pressure generating means, wherein the adjustment control means changes the operation value in a decreasing direction in accordance with a change speed of the operation value. 2. The wheel brake pressure control device according to claim 1, wherein when the change speed is high, the flow resistance of the selected flow passage is determined to be small. 4. A brake master cylinder for applying brake fluid pressure to a wheel brake, and a fluid pressure for driving a brake master cylinder by assisting an operation applied by a vehicle driver for wheel braking. The brake fluid of the brake master cylinder is sucked and discharged to the wheel brakes in order to give the wheel brakes a brake fluid pressure higher than the assisting limit of the booster and the fluid pressure booster. A hydraulic pressure source on the vehicle, including a pump for driving; supply pressure adjusting means between the hydraulic pressure source and the wheel brake for increasing and decreasing the wheel brake pressure; A wheel brake pressure control device comprising: operation value detection means for detecting an applied operation value; and adjustment control means for controlling flow of the supply pressure adjustment means based on the operation value. Means for detecting the pressure; A limit detecting means for detecting whether the star is less than the assist limit or an assist limit, wherein the supply pressure adjusting means is interposed between the hydraulic pressure source and a wheel brake, A plurality of flow paths having different flow resistances, a selective flow path including a connection control valve for opening and closing these flow paths; and a flow path between the suction side flow path of the pump and the output port of the hydraulic pressure generating means. A pressure control valve for controlling the flow of the brake fluid; wherein the adjustment control means drives the pump when the limit detection means detects the assisting limit, and operates the suction side flow path via the pressure control valve. The output port of the brake master cylinder is connected to the selected passage, and when the deviation between the two is large in the direction in which the deceleration exceeds the target value corresponding to the target value corresponding to the deceleration and the operation value, the flow through the selected communication passage is performed. A wheel brake pressure control device characterized in that flow resistance is set to a small value. 5. A brake master cylinder for applying brake fluid pressure to a wheel brake, and a fluid pressure for driving a brake master cylinder by assisting an operation applied by a vehicle driver for wheel braking. The brake fluid of the brake master cylinder is sucked and discharged to the wheel brakes in order to give the wheel brakes a brake fluid pressure higher than the assisting limit of the booster and the fluid pressure booster. A hydraulic pressure source on the vehicle, including a pump for pumping; supply pressure adjusting means between the hydraulic pressure source and the wheel brake for increasing and reducing the wheel brake pressure;
A wheel brake pressure control device comprising: an adjustment control means for controlling a flow of the supply pressure adjustment means; a limit detection means for detecting whether the hydraulic pressure booster is below an assist limit or an assist limit; and Means for detecting the rate of change of the operation value applied to the pressure booster; the supply pressure adjusting means being interposed between the hydraulic pressure source and the wheel brake, A plurality of flow paths having different flow resistances, a selective flow path including a connection control valve for opening and closing these flow paths; and a flow path between the suction side flow path of the pump and the output port of the hydraulic pressure generating means. A pressure control valve for controlling the flow of the brake fluid; wherein the adjustment control means drives the pump when the limit detection means detects the assisting limit, and operates the suction side flow path via the pressure control valve. To the output port of the brake master cylinder, The wheel brake pressure control device according to claim 1, wherein the flow resistance of the selected flow passage is determined to be small when the operation value is high in the decreasing direction in accordance with the change speed of the operation value. 6. The adjustment control means drives the pump when the limit detection means detects the assist limit at a speed corresponding to the changing speed of the operation value until the limit detection means detects the assist limit. The driving of the pump is stopped when a value less than the assisting limit is detected thereafter;
A wheel brake pressure control device according to any one of the preceding claims.