JPS62166147A - Brake control device - Google Patents

Abstract

PURPOSE:To keep a relationship between braking leg-power and deceleration constant by providing a means setting control load according to a control signal and outputting a signal thereafter without performing output hydraulic pressure control up to a fixed time set according to braking conditions from the start of brake operation. CONSTITUTION:The circuit from a master cylinder 21 to a wheel cylinder 28 is divided into a master cylinder hydraulic pressure system and a wheel cylinder hydraulic pressure system, and an accumulator 23 for absorbing the stroke of a brake pedal 20 is provided in the master cylinder hydraulic pressure system. And an output hydraulic pressure control valve 26 is provided in the wheel cylinder hydraulic pressure system, and controlled so as to obtain braking deceleration according to master cylinder hydraulic pressure. Target braking deceleration is performed to be obtained thereafter without performing output hydraulic pressure control up to a set time according to brake leg-power speed. Accordingly, coincidence with target deceleration is heightened.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a brake control device used in automobiles and the like.

(Prior art) As a conventional brake control device, for example,
-78847 publication (title of invention: brake booster)
A device such as that described in is known.

This conventional device controls the output of a brake system booster (brake booster) to maintain a constant relationship between brake pedal force and braking deceleration, and detects the pedal force applied to the brake pedal. A pedal force detecting means for outputting a pedal force signal, a deceleration detecting means for detecting deceleration of the vehicle due to braking and outputting a deceleration signal, a variable pressure chamber and a constant pressure chamber, and between the master cylinder and the brake pedal. An interposed booster, a fluid pressure supply source communicated with a variable pressure chamber of the booster, and a valve system disposed in a communication pipeline between the fluid pressure supply source and the variable pressure chamber and actuated by a valve drive signal. a function generator for outputting a target deceleration signal according to the pedal force signal; and inputting the target deceleration signal and the deceleration signal;
It was equipped with a comparator that outputs a valve drive signal so that the deceleration signal matches the target deceleration signal.

(Problem to be Solved by the Invention) However, with such conventional devices, although the relationship between brake pedal force and braking deceleration can be kept constant, the output from the brake booster is converted into hydraulic pressure. Since there was a single hydraulic pressure circuit from the master cylinder to the wheel cylinders, if the output hydraulic pressure was controlled from the start of brake operation, the hydraulic system's Guinamix etc. would cause the output from the booster to Since there is a time delay in the occurrence of deceleration, the overshoot of the output becomes large, resulting in a deceleration greater than the driver's intention and poor convergence to the target value. The problem remained that it gave a sense of discomfort to those who converted.

(Means for Solving the Problems) The present invention has been made for the purpose of solving the above-mentioned problems, and to achieve this purpose, the present invention employs the following solving means.

The solution of the present invention will be explained with reference to the conceptual diagram of the claim shown in FIG. , an output hydraulic pressure control valve 6 that controls the input hydraulic pressure Pp from the hydraulic pressure generating means 4 to the output hydraulic pressure Pw to the wheel cylinder 5, and a control load setting means that sets the control load Fc according to the control signal ■. 7, a deceleration sensor 8, and a pedal force sensor 9 are included as input sensors, and the output hydraulic pressure is not controlled from the start of the brake operation until a predetermined time set according to the braking state, and then the target brake reduction is determined according to the pedal force. The means includes a control means 10 for outputting a control signal @ from which a speed can be obtained to the control load setting means 7.

(Function) Therefore, in the brake control device of the present invention, as described above, the hydraulic circuit from the master cylinder to the wheel cylinder is connected to the hydraulic circuit from the master cylinder to the hydraulic pressure generating means, and from the hydraulic pressure generating means to the wheel cylinder. The other wheel cylinder hydraulic pressure system is divided into two systems, and the other wheel cylinder hydraulic pressure system is equipped with an output hydraulic pressure control valve, and this valve is controlled to obtain braking deceleration according to the pedal force, thereby controlling the brake pedal force and braking reduction. The relationship with speed can be kept constant.

Furthermore, output hydraulic pressure control is not performed from the start of brake operation until a predetermined time set depending on the braking state, and then
By controlling the output hydraulic pressure to obtain the target braking deceleration according to the pedal force, the output hydraulic pressure can be controlled to follow the occurrence of vehicle deceleration, and the overshoot of the output hydraulic pressure is small and the driver's intention is achieved. It is possible to improve the consistency with the target deceleration.

(Example) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In describing this embodiment, a brake control device used in an automobile will be taken as an example.

First, the configuration of the embodiment will be explained.

The brake control device A of the embodiment, as shown in FIG.
The master cylinder hydraulic system includes a brake pedal 20, a master cylinder 21, and master cylinder hydraulic oil passages 22, 22.
, an accumulator (stroke absorption means) 23.23, and the wheel cylinder hydraulic system includes a hydraulic pump (hydraulic pressure generation means) 24, an input hydraulic oil passage 25.25, an output hydraulic pressure control valve 26.26, and a wheel cylinder hydraulic system. Cylinder hydraulic oil passage 27
27, wheel cylinders 28, 28', a first solenoid valve 51 and a second solenoid valve 52 as control load setting means, a deceleration sensor 32 and a master cylinder hydraulic pressure sensor (pedal force sensor) as input sensors. )
33, and a control unit 34 using a microcomputer as a control means.

The master cylinder 21 is a means for converting the force applied to the brake pedal 20 into hydraulic pressure.

The master cylinder hydraulic oil passages 22.22 are oil passages through which oil of master cylinder hydraulic pressure Pm generated in the master cylinder 21 flows, one of which is a front master cylinder hydraulic oil passage, and the other is a rear master cylinder hydraulic oil passage. This is the cylinder hydraulic oil line.

Note that the term "hydraulic oil passage" includes an oil passage formed within the pipe and an oil passage formed within the valve body 35.

The accumulator 23.23 is provided in the master cylinder hydraulic oil passage 22.22, stores oil at the master cylinder hydraulic pressure Pm during brake operation, and adjusts the pedal stroke in response to the brake pedal force applied to the brake pedal 20 by controlling the master cylinder hydraulic pressure. This accumulator 23.23 is a means for maintaining a constant relationship in the same way as braking operation is performed by supplying the valve body 35 directly to the wheel cylinder.
formed within.

The hydraulic pump 24 serves as a hydraulic pressure source that generates hydraulic pressure to the wheel cylinders 28.28 during brake operation, and the suction oil passage 36.36 of this hydraulic pump 24 is connected to a reserve via a one-way valve 37.37. The discharge oil passage 39 is connected to the tank 38, and the output hydraulic pressure control valve 26.26 (input hydraulic oil passage 2
5°25) and the first solenoid valve 51 (input hydraulic oil passage 41).

Note that seven cumulators 42, 42 are provided in the discharge oil passages 39, 39 in order to reduce fluid pressure fluctuations.

The output hydraulic pressure control valve 26.26 is connected to the hydraulic pump 24.
The input hydraulic pressure Pp from the wheel cylinder 28.28'
This valve controls the output hydraulic pressure Pw to , and valves having the same structure are provided in parallel in the valve body 35.

Structurally, a valve hole 126 having ports 126a to 126d, and a land 226a corresponding to the valve hole 126.
, 226b and an axially movable spool 226;
A stepped piston hole 326 that has ports 326a and 326b and is formed on the left side of the spool 226 in the drawing; a stepped piston 426 that can reciprocate in the stepped piston hole 326 and contacts the spool 226; It is provided with a spring 526 that urges the user in the opposite direction.

The port L26a is connected to the drain oil passage 43.

126c is connected to the input hydraulic oil line 25.

Ports 126b and 126d are connected to output hydraulic oil passage 27.

Furthermore, the bow 326a is connected to the master cylinder hydraulic oil passage 22. port) 326b is the control signal hydraulic oil line 4
Connected to 4.

The wheel cylinder 28.28 is provided in a brake device (disc brake, drum brake, etc.) for the front and rear wheels,
These are members that apply braking force to the wheels using the output hydraulic pressure Pw, one of which is a front wheel cylinder and the other is a rear wheel cylinder.

First solenoid valve 51 and second solenoid valve 5
2 is a control signal hydraulic pressure P to the output hydraulic pressure control valve 26.
This is a hydraulic pressure control valve that generates c in response to a control signal (2) from the control unit 34, and is provided within the valve body 35.

The first solenoid valve 51 is normally closed and outputs a high control signal pressure Pc when the valve is opened, and the second solenoid valve 52 is a valve that is normally open and drains the control signal pressure Pc when the valve is open. , each solenoid valve 5
1.52 is ports 151a, 151b and 152a,
Valve hole 151.152 with 152b and port 1
Valve members 251 and 252 that open and close 51a and 152a
and a spring 3 that biases the valve members 251 and 252.
51, 352, and solenoids 451, 452 that apply electromagnetic force to the valve members 251, 252.

The ports 151a and 152a are connected to the control signal hydraulic oil passage 44, the port 151b is connected to the input hydraulic oil passage 41, and the port 152b is connected to the reserve tank 38.

The deceleration sensor 32 is a sensor that detects the deceleration of the vehicle and outputs a deceleration signal [phase] corresponding to the deceleration.

The master cylinder hydraulic pressure sensor 33 is a sensor that detects the master cylinder hydraulic pressure Pm and outputs a hydraulic pressure signal (■) according to the brake pedal force.

The control unit 34 inputs the deceleration signal [phase] from the deceleration sensor 32 and the hydraulic pressure signal (2) from the master cylinder hydraulic pressure sensor 33, processes it according to predetermined processing conditions, and controls the first solenoid valve. 51 and the second solenoid valve 52, the output hydraulic pressure is not controlled from the start of pressing the brake pedal 20 until the set time TO corresponding to the pressing speed, and then the target braking deceleration αi according to the brake pressing force is set. A control means for outputting the obtained control signal ■, the input circuit 134, RAM (random,
access, memory) 234, ROM (read, only, memory) 334, CPU (central, processing, 22)) 434. It includes a clock circuit 534 and an output circuit 634.

Note that the input circuit 134 is used to amplify input signals and
This is a circuit that converts the signal into a signal that can be processed by the RAM
234 is a memory circuit capable of writing and reading that temporarily writes input signals and temporarily writes information during processing; ROM 334 is a memory circuit that stores information necessary for control processing in advance; C
The PU 434 is a central processing circuit that performs comparison and arithmetic processing according to predetermined processing means, the clock circuit 534 is a circuit that sets control processing time, and the output circuit 634 outputs a control signal ■ based on the result signal from the CPU 434. This is a circuit that outputs.

The ROM 334 contains an arithmetic expression for calculating the target braking deceleration αi from the hydraulic pressure signal ■, an arithmetic expression for the rate of change at (brake depression speed) of the target braking deceleration αi, and an expression for calculating the rate of change &i.
The characteristic map M diagram (Fig. 3) between and the set time TO, the calculation formula for the braking deceleration difference Δα (=αi - αr), the control setting values εl and ε2 of the braking deceleration difference Δα, etc. are stored in advance. has been done.

Next, the operation of the embodiment will be explained.

First, the control operation in the control unit 34 of the embodiment will be described with reference to the flowchart shown in FIG.

(B) The flow of braking operation from the start of brake operation to the set time TO is as follows: Step 200 - Step 201 →
The flow of proceeding from step 202 → step 203 → step 204 is repeated, and the control signal (■) is not output from the control unit 34, and the output hydraulic pressure Pw is equal to the master cylinder hydraulic pressure Pm from the master cylinder hydraulic oil passage 22.22.
The standard hydraulic pressure is generated in accordance with the hydraulic pressure applied to the stepped piston 426 by the stepped piston 426.

Step 200 is a hydraulic pressure signal corresponding to the brake pedal force.
This is the loading step.

Step 201 is a calculation step in which a target braking deceleration αi is calculated based on the hydraulic pressure signal (master cylinder hydraulic pressure Pm) read in step 200.

Step 202 differentiates the target braking deceleration αi calculated in step 201 with respect to the rate of change ai (=dα
i/dt).

Step 203 is a search step for searching for the set time To using the rate of change &i calculated in step 202 and the characteristic map M.

Step 204 is a determination step in which the set time To retrieved in step 203 is compared with the time T from the start of the brake operation.

(b) When the set time TO has been exceeded from the start of the brake operation, the flow of control operation at this time is Step 200 → Step 201 → Step 202 → Step 203 → Step 2
04 → Step 205 → Step 206 → Step 20
7, and in step 207, the braking deceleration difference Δα and the control set value ε(ε1.

ε2) is compared, and when Δα is -ε2, the process proceeds to a pressure reduction output step 208 where the first solenoid valve 51 is closed (OFF signal) and the second solenoid valve 52 is opened (OFF signal), and -ε2 is compared. Δα×ε], the holding pressure output step 209 closes the first solenoid valve 51 (OFF signal) and closes the second solenoid valve 52 (ON signal).
Proceed to Δα〉ε! When , the first solenoid valve 51 is opened (ON signal) and the second solenoid valve 52 is closed (ON signal).
The process advances to step 210 for outputting a boosted pressure signal.

Step 205 is a reading step in which the actual braking deceleration αr is read based on the deceleration signal [phase] from the deceleration sensor 32.

Step 206 calculates the braking deceleration difference Δα (=αi
-αr).

Step 207 is a judgment step in which the braking deceleration Δα calculated in step 206 is compared with the control set value ε (ε1, ε2).

The output hydraulic pressure Pw is controlled by the control operation as described above, which will be described with reference to the time chart shown in FIG.

In this time chart, αro is the actual braking deceleration when the output hydraulic pressure Pwo is controlled immediately after the start of the brake operation, and Δα0 is the braking deceleration difference at this time.

First, looking at the output hydraulic pressure characteristic Pwo where the output hydraulic pressure is controlled immediately after the start of the brake operation, pressure increase control is performed for a while after the start of the brake operation due to the delay in the occurrence of the actual braking deceleration αro. When the difference from the target braking deceleration αi becomes within the control setting value, the output hydraulic pressure has already overshot, and even if the hydraulic pressure control for holding and reducing pressure is performed afterwards, the actual braking deceleration is higher than necessary. αro occurred, and the approximation of target output hydraulic pressure characteristic Pw* was low.

On the other hand, as in the embodiment, when the output hydraulic pressure Pw is controlled after the set time To has elapsed from the start of the brake operation, the hydraulic pressure is As shown in the output hydraulic pressure characteristic Pw, the overshoot of the output hydraulic pressure is suppressed, and a characteristic that closely approximates the target output hydraulic pressure characteristic Pw' is obtained.

As explained above, the brake control device A of the embodiment
In this case, the hydraulic pressure circuit from the master cylinder 21 to the wheel cylinder 28 is divided into two systems, a master cylinder hydraulic pressure system and a wheel cylinder hydraulic pressure system, and one master cylinder hydraulic pressure system includes a brake pedal 20. Since the accumulator 23 is provided to absorb the pedal stroke, the relationship between the brake pedal force and the brake stroke is kept constant, and the brake feeling is not deteriorated.

Further, the other wheel cylinder hydraulic pressure system is provided with an output hydraulic pressure control valve 26, and this valve 26 is controlled so as to obtain a braking deceleration according to the master cylinder hydraulic pressure Pm (corresponding to the brake pedal force). As a result, the relationship between the brake pedal force and the braking deceleration can be kept constant.

In addition, the output hydraulic pressure is not controlled from the start of the brake operation until the set time To according to the brake pedal speed, and then the hydraulic pressure is controlled to obtain the target braking deceleration αi according to the pedal force. The output hydraulic pressure control follows the occurrence of the actual braking deceleration αr, and the overshoot of the output hydraulic pressure Pw is small, and the consistency with the target braking deceleration αi intended by the driver can be improved.

Furthermore, in the embodiment, the accumulators 23, 23, hydraulic pump 24, output hydraulic pressure control valve 26, control signal hydraulic valve 29, oil passage, etc. are housed in one valve body 35, so the device is compact. can be achieved.

Next, another example of output hydraulic pressure control will be explained with reference to FIGS. 6 and 7.

The brake fluid pressure control device used in this embodiment is
Since this device is exactly the same as the device shown in the figure, only the different points will be described.

In contrast to the above-mentioned embodiment, in which the output hydraulic pressure Pw is controlled when the set time To corresponding to the brake pedal speed is exceeded after the start of the brake operation, this embodiment controls the output hydraulic pressure Pw from the start of the brake operation. The difference is that the output hydraulic pressure Pw is controlled when the braking deceleration αi exceeds the control set value ε3.

Therefore, in the flowchart diagram shown in FIG. 6, steps 202. Step 203. The difference is that step 204 is replaced by step 211, which is a step of determining the actual braking deceleration αi and the control set value ε3.

In the time chart shown in FIG. 7, although the method of setting the output hydraulic pressure control start timing is different, in this embodiment as well, the output hydraulic pressure is performed, so it exhibits almost the same characteristics as the previous example.

Although the embodiments of the present invention have been described above in detail with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention may be modified without departing from the gist of the present invention. included.

For example, in the embodiment, a spool valve type control valve is shown as the output hydraulic pressure control valve, but a control valve having another structure such as a Paul valve type control valve may be used.

In addition, in the embodiment, a control pressure setting valve having a solenoid valve structure is shown as a control load setting means, but even a valve operated by a motor actuator or an actuator directly generating a control load may be used. good.

In addition, in the embodiment, a master cylinder hydraulic pressure sensor that indirectly detects the brake pedal force is shown as the pedal force sensor, but
The brake pedal force may be directly detected, or the brake pedal force may be indirectly detected using a master cylinder stroke, an accumulator stroke, or the like.

In addition, in the embodiment, a sensor that directly detects deceleration is shown as the deceleration sensor, but other sensors such as a vehicle speed sensor (which can calculate deceleration by calculation), a wheel load sensor, etc.
A sensor that indirectly detects deceleration may also be used.

(Effects of the Invention) As explained above, in the brake control device of the present invention, the hydraulic pressure circuit from the master cylinder to the wheel cylinder is connected to the hydraulic pressure circuit from the master cylinder to the hydraulic pressure generating means.
The system is divided into two systems from the hydraulic pressure generating means to the wheel cylinder, and the other wheel cylinder hydraulic pressure system is provided with an output hydraulic pressure control valve, and this valve is controlled so as to obtain a braking deceleration according to the pedal force. As a result, it is possible to maintain the relationship between the brake pedal force and the braking deceleration constant.

Further, output hydraulic pressure control is not performed from the start of brake operation until a predetermined time set according to the braking state, and after that, output hydraulic pressure control is performed to obtain the target - braking deceleration according to the pedal force. This results in output hydraulic pressure control that follows the occurrence of vehicle deceleration, resulting in the effect that overshoot of the output hydraulic pressure is small and consistency with the target deceleration intended by the driver can be improved.

[Brief explanation of drawings]

Fig. 1 is a conceptual diagram of claims showing a brake control device of the present invention, Fig. 2 is a diagram showing a brake control device of an embodiment, and Fig. 3 is a diagram showing a brake control device of an embodiment.
The figure shows a characteristic map set in the control unit 7) of the embodiment, Fig. 4 is a flowchart showing the flow of control operations in the control unit of the embodiment device, and Fig. 5 shows the flow of control operations during braking in the embodiment device. Time chart diagram, 6th
FIG. 7 is a flowchart showing another example of the control operation in the control unit, and FIG. 7 is a time chart during braking in another example of the device. 1... Brake pedal 2... Master cylinder 3... Master cylinder hydraulic oil path 4... Hydraulic pressure generating means 5... Wheel cylinder 6... Output hydraulic pressure control valve 7... Control Load setting means 8... Deceleration sensor 9... Pedal force sensor 10... Control means

Claims (1)

[Scope of Claims] 1) A master cylinder that converts the force applied to the brake pedal into hydraulic pressure; the master cylinder hydraulic pressure and the control load are included in the signal load; and the input hydraulic pressure from the hydraulic pressure generating means is applied to the wheel cylinder. An output hydraulic pressure control valve that controls the output hydraulic pressure, a control load setting means that sets the control load according to a control signal, and an input sensor that includes a deceleration sensor and a pedal force sensor, and controls the control load according to the braking state from the start of the brake operation. and control means for not performing output hydraulic pressure control until a predetermined time set by the driver, and then outputting a control signal to the control load setting means to obtain a target braking deceleration according to the pedal force. Features a brake control device.