JPH11139297A - Vehicular brake control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicular brake control device which can simultaneously produce a suitable brake operating feel and operate an electric brake accurately and quickly and which enables proper braking action even when an electric system has failed. SOLUTION: When an electric system is operating normally, a brake operation detection unit 17 is made to receive hydraulic pressure which a master cylinder 13 outputs according to a braking operation, and the electric actuator 152 of a brake unit 15 is controlled according to a signal being proportional to the braking operation and output from the braking operation detection unit 17, to cause braking action. If the electric system has failed, the hydraulic pressure output by the master cylinder 13 is directly supplied to the hydraulic drive part 151 of the brake unit 15 to operate the brake unit 15 using the hydraulic pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is capable of generating a favorable operation feeling of a brake and accurately detecting the operation state of the brake, and appropriately operating a brake unit that is operated by electric power. Moreover, the present invention relates to a vehicle brake control device capable of ensuring proper operation of the brake unit even when an electric system fails.

[0002]

2. Description of the Related Art In recent years, brake systems for vehicles have been actively equipped with an intelligent brake function such as an anti-lock brake system and a traction control system. Brake devices are being electrified.

In the electrification of the brake device, a brake operation detecting unit for accurately detecting the operation state of the brake pedal by the driver and a brake operation detecting unit for operating the brake device as requested by the driver. The performance of the control unit, which controls the operation of the brake device based on the above signal, is an important point that determines the braking performance.

For example, in the related art, as shown in FIG. 6, a stepping force sensor 2 for detecting a stepping force of the brake pedal 1 by a driver is provided in a stepping portion 1a of a brake pedal 1 of a vehicle, as shown in FIG. A configuration with such a configuration has been developed. The brake pedal 1 itself normally provides a predetermined operation reaction force (brake feeling) when the driver steps down, and furthermore, when the driver releases his / her foot from the brake pedal 1, the brake pedal 1 It is elastically supported by the pedal urging spring 3 so as to return to the initial position.

The above-described treading force sensor 2 outputs an electric signal according to the treading force of the driver. The pedaling force applied to the pedaling force sensor 2 by the driver increases sharply as shown by the curve A in FIG. 7 during rapid braking, but gradually increases as shown by the curve B during gentle braking. Therefore, as shown in FIG. 8, if the electric signal output from the treading force sensor 2 is differentiated to determine the rate of increase of the treading force (the slopes of the curves A and B shown in FIG. 7), the braking is sudden or slow. It is possible to determine whether or not braking is being performed, and by controlling the operation of the braking device according to the determination result, it becomes possible to realize a braking operation required by the driver. In FIG. 8, the curve C corresponds to the curve A at the time of sudden braking in FIG. 7, and the curve D corresponds to the curve B at the time of gentle braking in FIG.

[0006]

However, as also shown by the curve A in FIG. 7, the treading force at the time of sudden braking includes noise n having a small amplitude, and the output signal of the treading force sensor 2 is differentiated. Then, since the noise n is amplified and affected as shown in FIG. 8, there is a possibility that the determination of the operation state of the brake pedal 1 (for example, whether or not sudden braking is performed) is erroneous due to the noise n. Performing a filtering process to remove the noise n in order to avoid such inconveniences makes it possible to more accurately determine the operation state of the brake pedal 1. A new problem that the time delay of the operation becomes large occurs.

In a conventional electric brake, for example,
In a disk brake device, a drive unit is simply electrified by, for example, moving a piston for pressing a brake pad against a disk by an electric motor. There is a problem that it cannot be secured.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and to generate a favorable operation feeling of the brake, detect the operation state of the brake accurately and promptly, and operate with an electric power. An object of the present invention is to provide a vehicular brake control device capable of operating a brake unit properly and ensuring proper operation of the brake unit even when an electrical system fails.

[0009]

According to the present invention, there is provided a brake control apparatus for a vehicle, comprising: a master cylinder for generating hydraulic pressure in response to a brake operation; a hydraulic drive unit and an electric actuator as drive sources; A brake unit that operates with hydraulic or electric power, and detects the brake operation state from the hydraulic pressure output by the master cylinder,
A brake operation detection unit that outputs a signal corresponding to a brake operation state, a solenoid valve for a sensor that opens and closes an oil passage that guides a hydraulic pressure output from the master cylinder to the brake operation detection unit, and a hydraulic pressure output from the master cylinder. A drive unit solenoid valve for opening and closing an oil passage leading to the hydraulic drive unit; and a control unit for controlling operations of the brake unit, the sensor solenoid valve, and the drive unit solenoid valve. The unit has an input chamber into which the hydraulic pressure of the master cylinder is introduced, a variable volume chamber communicating with the input chamber via an orifice, a piston sliding in the variable volume chamber, and reducing the volume of the variable volume chamber. A spring for urging the piston in the direction in which the pressure is applied, and first and second pressure sensors for detecting hydraulic pressures in the input chamber and the variable volume chamber, respectively. And a chromatography, wherein the control unit, the first, characterized in that receiving a signal from the second pressure sensor for controlling the electric actuator.

[0010] According to the above configuration, when the electric system is normal, the control unit closes the solenoid valve for the drive unit and opens the solenoid valve for the sensor to open the solenoid valve for the master cylinder. By causing the generated hydraulic pressure to be received by the brake operation detection unit and controlling the operation of the electric actuator of the brake unit based on a signal output from the brake operation detection unit,
The brake unit performs a predetermined braking operation. here,
The brake operation detection unit receives the hydraulic pressure output by the master cylinder in response to the brake operation in the input chamber and the variable volume chamber to absorb the hydraulic pressure, and at the same time, by the urging force of a spring for urging the piston in the variable volume chamber. An appropriate reaction force is transmitted to a brake pedal, which is a brake operating means.

Further, the brake operation detecting unit includes:
At the time of gentle braking in which the brake pedal is gently depressed, the liquid in the input chamber is gently pressurized by introducing the hydraulic pressure of the master cylinder, so the pressurized liquid in the input chamber is variable in volume through the orifice. Flow into the chamber and there is not much pressure difference between the input chamber and the variable volume chamber. On the other hand, at the time of rapid braking in which the brake pedal is suddenly depressed, the liquid in the input chamber is rapidly pressurized by the introduction of the hydraulic pressure of the master cylinder.
Although the hydraulic pressure in the variable volume chamber increases only slightly, the hydraulic pressure in the input chamber increases significantly, resulting in a large pressure difference between the input chamber and the variable volume chamber.

That is, the pressure difference between the input chamber and the variable volume chamber is information accurately representing the driver's operation of the brake pedal, and is input based on the detection values of the first and second pressure sensors. The braking operation required by the driver can be determined by detecting the pressure difference between the chamber and the variable volume chamber. Also,
The detection value of each pressure sensor only needs to simply calculate the difference, and does not perform the differentiation process. Therefore, noise added when the driver operates the brake pedal is not amplified.

The control unit, when a failure occurs in the electric system, closes the electromagnetic valve for the sensor and opens the electromagnetic valve for the drive unit in response to a brake operation. By supplying the hydraulic pressure generated by the master cylinder to the hydraulic drive unit of the brake unit, the brake unit can be driven by the hydraulic pressure.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a vehicle brake control device according to the present invention will be described below in detail with reference to the accompanying drawings. As shown in FIG. 1, a vehicle brake control device 10 of this embodiment includes a master cylinder 13 that generates a hydraulic pressure in accordance with a brake operation (step-down operation) on a brake pedal 11, and a hydraulic drive unit 151 as a drive source.
And a brake unit 15 that is provided with a hydraulic actuator or an electric actuator and that is operated by hydraulic power or electric power.
A brake operation detection unit 17 that outputs a signal corresponding to a brake operation state, and electromagnetic valves 22 and 23 for sensors that open and close oil passages 19 and 20 that guide hydraulic pressure output from the master cylinder 13 to the brake operation detection unit 17. ,
A solenoid valve 28 for a drive unit that opens and closes an oil passage 25 that guides the hydraulic pressure output from the master cylinder 13 to the hydraulic drive unit 151
And the brake unit 15 and the solenoid valve for sensor 2
2, 23 and a control unit 30 for controlling the operation of the solenoid valve 28 for the drive unit.

The brake pedal 11 is connected to a piston in the master cylinder 13, and the hydraulic pressure corresponding to the stepping down is output from the master cylinder 13. In this embodiment, the brake unit 15 is a disc brake unit, and the brake disc 153 is
54, 155 presses the hydraulic drive unit 151 or the electric actuator 1
52 is driven forward and backward. In the case of the present embodiment, the sensor solenoid valves 22 and 23 are normally closed solenoid valves, and the oil passages 19 and 20 are used during normal braking of the electric system.
Is opened. The drive unit solenoid valve 28 is a normally-open solenoid valve in the case of the present embodiment, and the oil passage 25 remains open when a failure of the electric system occurs.

As shown in FIG. 2, the brake operation detecting unit 17 is provided with an input chamber 32 into which the hydraulic pressure of the master cylinder 13 is introduced and an input chamber 32 through an orifice 36 formed in a one-way valve 34. Variable volume chamber 38 communicating with
A piston 40 that slides in the variable volume chamber 38, and a piston 40 that reduces the volume of the variable volume chamber 38.
, And first and second pressure sensors 44 and 45 for detecting the hydraulic pressures of the input chamber 32 and the variable volume chamber 38, respectively.

The one-way valve 34 is, as shown in FIG.
A valve housing 51 that forms a communication passage 48 that communicates the input chamber 32 and the variable volume chamber 38 and that is provided with a valve seat portion 49 with a reduced diameter in the middle of the communication passage 48.
And a valve body 53 slidable in the communication passage 48 of the valve housing 51.

The valve body 53 has a structure in which the orifice 36 is formed at the center thereof. When the pedal pressure of the master cylinder 13 increases, the hydraulic pressure from the input chamber 32 increases. The communication passage 48 is seated on the valve seat 49 to reduce the diameter of the communication passage 48 to the diameter of the orifice 36, and is separated from the valve seat 49 to release the restriction of the communication passage 48 during a pedal return operation in which the oil pressure of the master cylinder 13 decreases. The valve element 53 is urged toward the valve seat 49 by a valve element urging spring 55 so that the valve element 53 is kept seated on the valve seat 49. When the driver's depression of the brake pedal 11 is released and the spring 42 pressurizes the piston 40 to return the liquid in the variable volume chamber 38 to the input chamber 32, the valve urging spring 55 The urging force is set to an appropriate value so that the valve element 53 is quickly separated from the valve seat 49 by the liquid pressure of the liquid returning from the variable chamber 38 to the input chamber 32, and the flow path is opened.

The control unit 30 closes the electromagnetic valves 28 for the drive unit and keeps the electromagnetic valves 22 and 23 for the sensors open during braking when the electric system is normal, and controls the brake operation detecting unit. 17
The brake operation state is detected by signals from the first and second pressure sensors 44 and 45, and the electric actuator 15 of the brake unit 15 is operated in accordance with the brake operation state.
In addition to controlling the operation of Step 2, when the electric system fails to operate the electric actuator 152 normally, the electromagnetic valves for sensors 22 and 23 are closed and the electromagnetic valves 28 for each drive unit are opened simultaneously. Then, the brake unit 15 is operated by hydraulic pressure by introducing the output hydraulic pressure of the master cylinder 13 to the hydraulic drive unit 151.

The control unit 30 operates the electric actuator 152 of the brake unit 15 according to the procedure shown in FIG. That is, at step S1, each variable n, P1 (n), P2 (n) and l
(N) is initialized. The control current l (n) initialized in step S2 is sent to the electric actuator 152 of the brake unit 15. In step S3, 1 is added to the counter variable n. First and second in step S4
The pressure sensors 44 and 45 measure the hydraulic pressures P1 (n) and P2 (n) of the input chamber 32 and the variable volume chamber 38, respectively. Then, in step 5, it is determined whether or not the hydraulic pressure P1 (n) of the input chamber 32 has exceeded the threshold value K1, and if the hydraulic pressure P1 (n) is equal to or less than the threshold value K1, the process returns to step S1. If the hydraulic pressure P1 (n) exceeds the threshold value K1, it is determined that the depression of the brake pedal 11 has been started, and the process proceeds to step S6.

In step S6, the hydraulic pressure P2 measured this time
(N) is the hydraulic pressure P2 (n−
It is determined whether or not P2 (n)> P2
In the case of (n-1), it is determined that the brake pedal 11 is being depressed, and the process proceeds to step S7. Then, in step S7, the hydraulic pressure P1 (n) of the input chamber 32 and the
The differential pressure ΔP from the hydraulic pressure P2 (n) of No. 8 is calculated. In step S8, the differential pressure ΔP is added to the previous control current value l (n−1).
Is added, and the current control current value l (n) is calculated. In step S9, the control current value l (n) is output to the electric actuator 152 of the brake unit 15, and a braking force proportional to the control current value l (n) is generated. Thereafter, returning to step S3, a correction current value f1 (ΔP) proportional to the differential pressure ΔP is obtained, and control with good response is performed from gentle braking to panic braking.

The current hydraulic pressure P2 of the variable volume chamber 38
When (n) becomes lower than the previous hydraulic pressure P2 (n-1), it is determined that the brake pedal 11 is being returned, and the determination in step S6 is No, and the process proceeds to step S10. In step S10, the hydraulic pressure P2 (n) of the variable volume chamber 38 is compared with the threshold value K2. If the hydraulic pressure P2 (n) is larger than the threshold value K2, the control current value l is proportional to the hydraulic pressure P2 (n) in step S11. (N) = f2 (P2 (n)) is calculated, and step S
9, the electric actuator 15 of the brake unit 15
2 is output. If No is determined in step S10, it is considered that the brake pedal 11 has been completely returned, and the process returns to step S1.

In the vehicle brake control device 10 of the present embodiment described above, the control unit 30
When the electric system is normal, the solenoid valve 28 for the drive unit is closed and the solenoid valves 22 and 23 for the sensor are opened so that the hydraulic pressure generated by the master cylinder 13 is received by the brake operation detecting unit 17. By controlling the operation of the electric actuator 152 of the brake unit 15 based on the signal output from the brake operation detection unit 17, the brake unit 15 performs a predetermined braking operation. Here, the brake operation detecting unit 17 receives the hydraulic pressure output by the master cylinder 13 in response to the brake operation in the input chamber 32 and the variable volume chamber 38 and absorbs the hydraulic pressure, and at the same time, the piston in the variable volume chamber 38 4
A suitable operation feeling of the brake is generated by transmitting an appropriate reaction force to the brake pedal which is a brake operation means by the urging force of the spring 42 for urging 0.

The brake operation detecting unit 17
When the brake pedal is slowly depressed, the input chamber 32 is introduced by the introduction of the hydraulic pressure of the master cylinder 13 during slow braking.
Since the liquid in the input chamber 32 is gradually pressurized, the pressurized liquid in the input chamber 32 is supplied through the orifice 36 to the variable volume chamber 38.
And the pressure difference between the input chamber 32 and the variable volume chamber 38 is not so large. On the other hand, at the time of rapid braking in which the brake pedal is rapidly depressed, the liquid in the input chamber 32 is rapidly pressurized by the introduction of the hydraulic pressure of the master cylinder 13, so that the passage of the orifice 36 is delayed. However, the hydraulic pressure in the variable volume chamber 38 increases only slightly, but the hydraulic pressure in the input chamber 32 increases significantly, resulting in a large pressure difference between the input chamber 32 and the variable volume chamber 38. .

That is, the pressure difference ΔP between the input chamber 32 and the variable volume chamber 38 is information that accurately represents the operating state of the driver's brake pedal, and as shown in FIG. Detecting the pressure difference ΔP between the input chamber 32 and the variable volume chamber 38 based on the detection values of the first and second pressure sensors 44 and 45, corresponding to slow braking, normal braking, sudden braking, and panic braking. Thus, the braking operation requested by the driver can be determined. Further, the detection values of the pressure sensors 44 and 45 need only be simply calculated as a difference, and the differential processing is not performed. Therefore, noise added when the driver operates the brake pedal is not amplified.
Therefore, there is no need to perform filter processing or the like for removing noise, it is possible to prevent delay in detection processing due to filter processing or the like, and it is possible to accurately and quickly detect the operation state of the brake and operate the brake operated by electric power. The unit 15 can be operated properly and with excellent responsiveness.

The control unit 30
When the failure occurs in the electric system, the solenoid valves 22 and 23 for the sensor are closed and the solenoid valve 2 for the drive unit is closed.
8 is opened, the hydraulic pressure generated by the master cylinder 13 in response to the brake operation is reduced.
5 to the hydraulic drive unit 151, and the brake unit 1
5 can be hydraulically driven. Therefore, even if a failure occurs in the electric system, proper operation of the brake unit 15 according to the brake operation can be ensured, and reliability and safety of the brake operation can be improved.

Further, in the case of the present embodiment, a one-way valve 34 is provided between the input chamber 32 and the variable volume chamber 38, and the valve body 53 of the one-way valve 34 is provided with the input chamber 32 and the variable volume chamber 38. The orifice 36 for communicating the
When the depression of the brake pedal 11 is released, the input chamber 32 and the variable volume chamber 38 communicate with each other through the communication path 48 having a diameter larger than that of the orifice 36, and flowed from the input chamber 32 into the variable volume chamber 38. The liquid can be returned quickly, and the return of the brake pedal 11 to the initial position can be expedited.

[0028]

As described above, according to the brake control apparatus for a vehicle of the present invention, when the electric system is normal, the control unit closes the solenoid valve for the drive unit and controls the electromagnetic valve for the sensor. With the valve opened, the hydraulic pressure generated by the master cylinder is received by the brake operation detection unit, and the operation of the electric actuator of the brake unit is controlled based on a signal output from the brake operation detection unit, thereby providing a brake. The unit performs a predetermined braking operation. Here, the brake operation detection unit receives the hydraulic pressure output by the master cylinder in response to the brake operation in the input chamber and the variable volume chamber to absorb the hydraulic pressure, and at the same time, activates the spring that biases the piston in the variable volume chamber. By transmitting an appropriate reaction force to the brake pedal as the brake operating means by the urging force, a favorable operation feeling of the brake is generated.

Further, the brake operation detecting unit includes:
At the time of gentle braking in which the brake pedal is gently depressed, the liquid in the input chamber is gently pressurized by introducing the hydraulic pressure of the master cylinder, so the pressurized liquid in the input chamber is variable in volume through the orifice. Flow into the chamber and there is not much pressure difference between the input chamber and the variable volume chamber. On the other hand, at the time of rapid braking in which the brake pedal is suddenly depressed, the liquid in the input chamber is rapidly pressurized by the introduction of the hydraulic pressure of the master cylinder.
Although the hydraulic pressure in the variable volume chamber increases only slightly, the hydraulic pressure in the input chamber increases significantly, resulting in a large pressure difference between the input chamber and the variable volume chamber.

That is, the pressure difference between the input chamber and the variable volume chamber is information that accurately represents the driver's operation of the brake pedal, and is input based on the detection values of the first and second pressure sensors. The braking operation required by the driver can be determined by detecting the pressure difference between the chamber and the variable volume chamber. Also,
The detection value of each pressure sensor only needs to simply calculate the difference, and does not perform the differentiation process. Therefore, noise added when the driver operates the brake pedal is not amplified. Therefore, there is no need to perform filter processing or the like for removing noise, it is possible to prevent delay in detection processing due to filter processing or the like, and it is possible to accurately and quickly detect the operation state of the brake and operate the brake operated by electric power. The unit properly,
It can be operated with excellent responsiveness.

When the electric system fails, the control unit closes the solenoid valve for the sensor and opens the solenoid valve for the drive unit to respond to a brake operation. Thus, the hydraulic pressure generated by the master cylinder can be supplied to the hydraulic drive unit of the brake unit to hydraulically drive the brake unit. Therefore,
Even if a failure occurs in the electric system, proper operation of the brake unit according to the brake operation can be ensured, and reliability and safety of the brake operation can be improved.

[Brief description of the drawings]

FIG. 1 is an embodiment of a vehicle brake control device according to the present invention, and is a schematic configuration diagram at the time of braking when an electric system is normal.

FIG. 2 is an enlarged sectional view of the brake operation detecting unit shown in FIG.

3 is an enlarged sectional view of a one-way valve in the brake operation detection unit shown in FIG.

FIG. 4 is a flowchart showing a procedure of a control operation in the control unit shown in FIG. 1;

FIG. 5 is a correlation diagram showing a correspondence between a detected pressure difference and a braking operation requested by a driver in the brake operation detection unit shown in FIG. 1;

FIG. 6 is a schematic configuration diagram of a conventional brake operation detection unit.

FIG. 7 is a pedal force characteristic diagram showing a difference between a sudden braking operation and a gentle braking operation of a pedaling force acting on a brake pedal.

8 is an explanatory diagram of a differential value of the pedaling force shown in FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 vehicle brake control device 11 brake pedal 13 master cylinder 15 brake unit 151 hydraulic drive unit 152 electric actuator 17 brake operation detection unit 19, 20 oil passage 22, 23 solenoid valve for sensor 25 oil passage 28 solenoid valve for drive unit 30 control Unit 32 input chamber 34 one-way valve 36 orifice 38 variable volume chamber 40 piston 42 spring 44, 45 first and second pressure sensors 48 communication passage 49 valve seat 51 valve housing 53 valve body 55 valve body biasing spring

Claims (1)

[Claims] 1. A master cylinder that generates a hydraulic pressure in accordance with a brake operation, a brake unit that includes a hydraulic drive unit and an electric actuator as a drive source and operates by hydraulic pressure or electric power, and a hydraulic pressure output by the master cylinder. A brake operation detection unit that detects a brake operation state and outputs a signal corresponding to the brake operation state; a sensor solenoid valve that opens and closes an oil passage that guides a hydraulic pressure output from the master cylinder to the brake operation detection unit; A solenoid valve for a drive unit that opens and closes an oil passage that guides a hydraulic pressure output from a master cylinder to the hydraulic drive unit, and the brake unit;
A control unit that controls the operation of the electromagnetic valve for the sensor and the electromagnetic valve for the drive unit, wherein the brake operation detecting unit is configured to receive the input pressure via an orifice and an input chamber into which a hydraulic pressure of a master cylinder is introduced. A variable volume chamber communicating with the chamber, a piston sliding in the variable volume chamber, a spring for urging the piston in a direction to decrease the volume of the variable volume chamber, a liquid in the input chamber and the liquid in the variable volume chamber. A first and a second pressure sensor for respectively detecting pressure, wherein the control unit controls the electric actuator in response to a signal from the first and the second pressure sensors. Brake control device.