JPH0565061A - Car brake control device safety mechanism and brake actuator - Google Patents

Abstract

PURPOSE:To generate a brake force even when brake force has vanished due to electrical failure by installing a brake operating mechanism of mechanical type in a brake actuator which performs braking operation with electrical signals. CONSTITUTION:A solenoid valve 8 takes the A position while a brake device is operating normally, so as to shut the communication of an oil path 10 leading from a master cylinder 2 to a wheel 9. When the brake device electrically driven goes in failure, the solenoid valve 8 is turned into B position to connect the master cylinder 2 with the wheel, and it is possible to supply the oil pressure generated by the master cylinder 2 to the wheel cylinder. When brake actuators 6, 6' are operated with a signal from an electronic control device ECU 5 while the solenoid valve 8 is in A position, brakes can be applied to the wheels 9, 11, and when the valve 8 is turned into B position in the event of failure occurrence in the electric system, brakes can be applied to the wheel 9 with the oil pressure generated by the master cylinder 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safety mechanism for a vehicle brake control device, and more specifically, a combination of an electric braking device (so-called by-wire braking device) and a mechanical braking device. By doing so, the present invention relates to a safety mechanism of a vehicle brake control device in which a mechanical brake device is activated immediately even if an electrical failure occurs in the by-wire brake device. The present invention relates to a brake actuator suitable for a vehicle brake control device.

[0002]

2. Description of the Related Art Usually, a vehicle brake control device using a so-called by-wire type brake device which operates a brake by an electric signal is disclosed in JP-A-62-2168.
No. 52, JP-A-2-267056 and the like are known. These vehicle brake control devices
In each case, the sensor detects the pedaling force or stroke of the brake pedal, and the brake actuator is controlled by the electric control device according to the output from the sensor, whereby a predetermined brake pressure can be generated in the wheel cylinder provided on the wheel. It was done like this.

[0003]

By the way, the above-mentioned by-wire type braking device can easily be variously controlled by an electric signal, and therefore is particularly suitable for an anti-skid braking system or a traction control system. Since the structure is simpler than that of the conventional mechanical type, its usability may increase in the future. However, these vehicle brake control devices are designed to electrically control all of the brake operating force based on a signal from a sensor that detects a pedaling force or a stroke of a brake pedal, that is, a conventional brake control device. Since it is an electric control mechanism that is different from a mechanical brake actuation mechanism that uses hydraulic pressure or a mechanical link, if an electrical failure such as a sensor failure or wire breakage occurs, the brake will not operate and safety There was a big problem. A brake actuator used for such a by-wire type brake device is disclosed in the above-mentioned Japanese Patent Laid-Open No. 62-2168.
No. 52 and Japanese Patent Laid-Open No. 2-267056, the structure is complicated because an initial operation is performed by a spool valve or the like and another piston is actuated to generate a brake pressure. There was a problem.

In view of the above, the present invention uses a mechanical type braking device in addition to the above-mentioned by-wire type braking device so that the braking force can be generated even when the braking force is lost due to an electrical failure. The present invention aims to solve the above problems and proposes a brake actuator having a simple structure suitable for use in the above-mentioned by-wire type brake device.

[0005]

Therefore, the first technical solution of the present invention is a vehicle brake capable of braking the wheels 9 and 11 by generating a brake pressure in response to a signal from the electronic control unit 5. In the control device, when an electrical defect occurs in the vehicle brake control device, the mechanical brake device is automatically operated, and the second technical solution means is an electronic device. A brake actuator 6, based on a signal from the control device 5,
In a vehicle brake control device capable of driving 6'to generate a brake pressure and brake the wheels 9 and 11, an oil passage 10 connecting the brake actuator 6 and a wheel cylinder provided on the wheel 9 is provided. An electromagnetic valve 8 that connects the hydraulic pressure generating device 2 and the oil passage is provided, and in an emergency, the electromagnetic valve 8 is switched so that the wheels 9 can be braked by the hydraulic pressure from the hydraulic pressure generating device 2. According to the third technical solution, the brake actuators 6 are arranged corresponding to each of the left and right front wheels, and are connected to the oil passages connecting the brake actuators 6 and the wheel cylinders provided on the wheels 9. The fourth technical solution is characterized in that electromagnetic valves 81 and 82 are arranged. The by-wire type vehicle brake control device is the fourth technical solution means. Suitable A brake actuator, the brake actuator is an electronic control unit 5
A motor 20 driven by a signal from the motor 20, a screw member 23 rotated by the drive of the motor 20, and a piston configured to move in the cylinder by the rotation of the screw member 23 to generate a hydraulic pressure in a hydraulic pressure generating chamber 28. According to a fifth technical solution, the piston 24 of the brake actuator is fixed to a nut member 30 screwed to the screw member 23, and the nut member 30 is the same as the nut member 30 described above. It is characterized in that it is slidably and non-rotatably supported in the cylinder, and these are means for solving the problems.

[0006]

The solenoid valve 8 is in the A position during normal operation of the by-wire type brake device, and disconnects the communication between the master cylinder 2 and the wheel 9 with the oil passage 10. However, once an abnormality occurs in the by-wire system, the solenoid valve 3 is switched to the B position, the master cylinder 2 and the wheel 10 are connected, and the hydraulic pressure generated in the master cylinder 2 can be supplied to the wheel 10. Therefore, when the solenoid valve 8 is in the A position, the brake actuators 6, 6'can be actuated by a signal from the electronic control unit ECU to brake the wheels 9, 11, and an abnormality occurs in the by-wire type brake device. When the solenoid valve 8 is switched to the B position, the wheels 9 can be braked by the hydraulic pressure generated in the master cylinder 2.

In the brake actuators 6 and 6 ', when the motor 20 is driven by a signal from the electronic control unit ECU, the pinion 21 and the gear 22 rotate, and the screw 23 rotates accordingly. The rotation of the screw 23 is transmitted to the nut 30, and the nut 30 moves leftward in the drawing on the screw 23 while being restricted in rotation by the detent 26. By the movement of the nut 30, the piston 24 integrated with the nut 30 also moves to the left in the figure against the biasing force of the spring 31, and a predetermined hydraulic pressure is generated in the hydraulic pressure generation chamber 28. The hydraulic pressure generated in the hydraulic pressure generation chamber 28 is supplied to the wheel cylinders mounted on the wheels, and the wheels can be braked. When the driving force from the motor 20 disappears, the piston 24 returns to the initial state by the urging force of the spring 31.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a conceptual diagram of a safety mechanism of a vehicle brake control device according to a first embodiment of the present invention. In FIG. 1, 1 is a brake pedal, 2 is a master cylinder as a hydraulic pressure generator, and 3 is a sensor for detecting a brake pedal force or a stroke of the brake pedal. The sensor 3 is composed of, for example, a potentiometer that can detect the position of the brake pedal, a pedaling force, and a stroke amount using a photo interface. The master cylinder 2 is connected to an oil passage 10 of two wheels (front wheels in this case) 9 via an A, B2 position switching electromagnetic valve 8 having a function to be described later, and an oil connecting the two wheels 9 is connected. The passage 10 is connected to a brake oil pressure sensor 7 and a brake actuator 6 that generates a brake pressure by a by-wire method via the solenoid valve 8, respectively. The remaining two wheels (rear wheels) 11 are provided with a brake actuator 6 ′ that generates a brake pressure by a by-wire method in the oil passage 1.
Connected by two. The details of the mechanism of the brake actuators 6 and 6'will be described later.

While the by-wire type brake device is operating normally, the solenoid valve 8 is in the A position as shown in the figure, and disconnects the communication between the well-known master cylinder 2 and the oil passage 10. However, once an abnormality occurs in the by-wire type brake device, the solenoid valve 8 is switched to the B position, the master cylinder 2 and the oil passage 10 are connected, and the oil pressure generated in the master cylinder 2 can be supplied to the oil passage 10. Is becoming Therefore, when the solenoid valve 8 is in the state shown in the figure (in the case of the by-wire system), when the brake actuators 6 and 6'are operated by the signal from the electronic control unit ECU, the wheels 9,
11 can be braked, and if an abnormality occurs in the by-wire system and the solenoid valve 3 is switched to the B position, the hydraulic pressure generated in the master cylinder 2 can brake the wheels 9.

The electronic control unit ECU is connected to the sensor 3 for detecting the brake depression force or the stroke of the brake pedal, the battery sensor 4, the brake actuators 6 and 6 ', and the hydraulic pressure sensor 7, and has the following functions. .. That is, when a signal corresponding to the brake pedal force or the stroke is output from the sensor 3 for detecting the brake pedal force or the stroke of the brake pedal to the electronic control unit ECU, the electronic control unit ECU applies a current proportional to the signal from the sensor 3 to the brake. It is supplied to the actuator to generate a predetermined brake pressure in the brake actuator. Further, during the control by the by-wire system, the function that can control the brake actuator by the signal from the hydraulic pressure sensor 7, and when the signal from the battery sensor 4 or the by-wire system is abnormal, the by-wire system is switched to the mechanical brake operating system. It has the function and.

The above-mentioned brake actuators 6 and 6'are of a type in which a piston in a normal master cylinder can be moved by a motor to generate a predetermined brake pressure as shown in FIG. The structure of the brake actuator will be described below with reference to FIG. 3. The brake actuators 6 and 6 ′ are a motor 20, a pinion 21 and a gear 22 rotated by the motor 20, and a screw as a screw member fixed to the gear 22. 23, a piston 24 screwed to the screw 23, a hydraulic pressure generation chamber 28 that generates hydraulic pressure by the movement of the piston, a reservoir 27
And a housing 29 capable of efficiently storing these members
It consists of and. The piston 24 is slidably fitted in a cylinder formed in a housing 29, and a nut 30 as a nut member screwed with the screw 23 is fixed to the piston 24. The nut 30 has a groove 25 in the screw axial direction on the outer periphery thereof, and a detent 26 is fitted in the groove 25 so that the nut 30 does not rotate in the cylinder even if the screw 23 rotates. Has been done. Again piston 2
4 is always urged to the right in the figure by a spring 31.

Therefore, the brake actuator 6,
6'is the motor 2 in response to a signal from the electronic control unit ECU.
When 0 is driven, the pinion 21 and the gear 22 rotate,
Along with this, the screw 23 rotates. Screw 2
The rotation of 3 is transmitted to the nut 30, and the nut 30 moves on the screw 23 to the left in the figure while the rotation is restricted by the rotation stopper 26. By moving the nut 30, the nut 30
The piston 24, which is integral with, also moves to the left in the drawing against the biasing force of the spring 31, and generates a predetermined hydraulic pressure in the hydraulic pressure generation chamber 28. The hydraulic pressure generated in the hydraulic pressure generation chamber 28 is supplied to the wheel cylinders mounted on the wheels, and the wheels can be braked. When the driving force from the motor 20 disappears, the piston 24 returns to the initial state by the urging force of the spring 31. As described above, the brake actuators 6 and 6'can apply the brakes to the wheels when the motor is driven by the by-wire system while adopting the master cylinder structure.

The details of the operation of the brake control device for a vehicle having the above-described structure will be described below separately for the by-wire system and the mechanical system. [Brake Control by By-Wire System] When the by-wire system brake device is normally operating, the brake is controlled by a signal from the electronic control unit ECU. Specifically, when the brake pedal is depressed and the pedaling force or stroke of the brake pedal 1 is detected by the sensor 3, the electronic control unit ECU actuates the brake actuators 6, 6'as described above based on this signal to operate the wheels 9,
You can brake the eleven. The braking force at this time is controlled by a signal from the sensor 3 or the hydraulic sensor 7. This by-wire type braking device can switch the solenoid valve 3 immediately when an abnormality occurs in the signals from the sensor 3, the battery sensor 4, the hydraulic pressure sensor 7 and the like, so that the by-wire type braking device can be switched to the mechanical type braking device. I am doing it.

[Brake Control by Mechanical System] When the by-wire system is operating normally, the solenoid valve 8 is in the A position, so the brake is controlled as described above by the signal from the electronic control unit ECU. However, when an abnormality occurs in the by-wire system, the solenoid valve 8 is immediately switched to the B position, and the wheels 9 can be braked by the hydraulic pressure generated in the master cylinder 2. Although hydraulic pressure is generated in the master cylinder 2 when the brake pedal of the by-wire system is operated, this hydraulic pressure is allowed to flow back to the reservoir 2 via a check valve (not shown), or the brake pedal has a predetermined stroke. Inconvenience caused by the generation of hydraulic pressure in the master cylinder by various measures such as placing it as a mechanism that can generate the brake pressure only when it exceeds the limit, or further providing an accumulator between the solenoid valve 8 and the master cylinder 2. Can be eliminated. When the accumulator is used, this hydraulic pressure can be used for traction control while controlling the solenoid valve 8.

A second embodiment will be described with reference to FIG. FIG. 2 is a conceptual diagram of a safety mechanism of a vehicle brake control device according to a second embodiment of the present invention. In this embodiment, the oil passages connecting the master cylinder 2 and the wheels 9 are solenoid valves 81, 82.
This is different from that of the first embodiment in that the brake accumulators 6 and 6 are branched at the upstream of the above, and the brake accumulators 6 and 6 are arranged in the respective oil passages. Therefore, in this embodiment, the left and right wheels 9, 9 can be controlled separately, and the safety can be improved. The rest of the configuration and operation are the same as those of the first embodiment.

In the safety mechanism of the vehicle brake control device of the present invention, which has been described based on the respective embodiments, the brake control is normally performed by the by-wire system while the electrical failure such as a sensor failure or a wire breakage occurs. When a failure occurs, the brake can be immediately actuated by the mechanical braking method, so that it is possible to provide a very safe vehicle brake control device. Further, the brake actuator of the vehicle brake control device of the present invention drives the motor to move the piston arranged in the cylinder to generate a predetermined hydraulic pressure in the hydraulic pressure generation chamber 28 in response to a signal from the electronic control unit ECU. Therefore, a brake actuator having a simple structure can be obtained.

The mechanism of the brake actuator 6 is not limited to the one described above, and for example, a mechanism for operating a piston using a linear motor or JP-A-62-21685.
Various mechanisms such as a mechanism for operating a piston using the electrostrictive element described in No. 2 can be adopted. Further, the mechanical brake system may be adopted not only on the front wheel side as in the above-described embodiment but also on all wheels or only the rear wheel side.

[0018]

As described in detail above, according to the present invention, the solenoid valve is immediately switched even if the brake actuator cannot be operated due to an electrical failure in the by-wire type vehicle brake control device. It is possible to operate the brake with a mechanical brake device, to obtain an extremely safe vehicle brake control device, and to obtain an excellent effect such as to obtain a brake actuator with a simple structure. be able to.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a safety mechanism of a vehicle brake control device according to a first embodiment of the present invention.

FIG. 2 is a conceptual diagram of a safety mechanism of a vehicle brake control device according to a second embodiment of the present invention.

FIG. 3 is a sectional view of a brake actuator used in the present invention.

[Explanation of symbols]

 1 Brake Pedal 2 Hydraulic Pressure Generation Device (Master Cylinder) 3 Sensor 4 Battery Sensor 5 Electronic Control Device 6, 6'Brake Actuator 7 Hydraulic Pressure Sensor 8 Solenoid Valve 9 Wheel 10 Oil Path

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kei Kunimi 5-4-71 Higashi, Hanyu City, Saitama Prefecture, Akebono Brake Central Technology Research Institute Co., Ltd. (72) Inventor Tadashi Kobayashi 5-4-171 East, Hanyu City, Saitama Prefecture Company Akebono Brake Central Technical Research Institute (72) Inventor Masahiro Nezu 5-4-71 Higashi, Hanyu City, Saitama Prefecture Akebono Brake Central Technical Research Institute (72) Inventor Kimio Takahashi 5-4-171 East Hanyu, Saitama Company Akebono Brake Central Technical Research Institute (72) Inventor Masatomo Mori 5-4-71 Higashi, Hanyu City, Saitama Prefecture Akebono Brake Central Technical Research Institute (72) Inventor Takashi Kurosawa 5-471 Higashi, Hanyu City Saitama Akebono Brake Central Technology Research Institute Co., Ltd.

Claims (5)

[Claims] 1. In a vehicle brake control device capable of generating a brake pressure by a signal from an electronic control device 5 to brake a wheel 9, 11, an electrical defect has occurred in the vehicle brake control device. Occasionally, a safety mechanism for a vehicle brake control device is characterized in that the brake device is automatically activated mechanically. 2. A vehicle brake control device capable of driving brake actuators 6, 6'by a signal from an electronic control device 5 to generate a brake pressure to brake wheels 9, 11, wherein said brake actuator 6 is used. A solenoid valve 8 that connects the oil pressure generating device 2 and the oil passage 10 is provided in an oil passage 10 that connects a wheel cylinder provided to the wheel 9 to the wheel cylinder. 2. A safety mechanism for a vehicle brake control device, characterized in that the wheels 9 can be braked by the hydraulic pressure. 3. The brake actuator 6 is arranged corresponding to each of the left and right front wheels, and solenoid valves 81, 82 are arranged in respective oil passages connecting the brake actuator 6 and a wheel cylinder provided on the wheel 9, 2. The safety mechanism of the vehicle brake control device according to claim 1, wherein the solenoid valves are switched in an emergency so that each wheel 9 can be braked by the hydraulic pressure from the hydraulic pressure generator 2. .. 4. Brake actuators 6 and 6 ′ capable of generating a predetermined hydraulic pressure in wheel cylinders provided on wheels 9 and 11, said brake actuator being driven by a signal from an electronic control unit 5. A motor 20; a screw member 23 that is rotated by the drive of the motor 20; and a piston 24 that is configured to move in the cylinder by the rotation of the screw member 23 and generate a hydraulic pressure in a hydraulic pressure generating chamber 28. A brake actuator for a vehicle brake control device. 5. The piston 24 is a screw member 23.
The vehicle brake control device according to claim 3, wherein the brake member is fixed to a nut member 30 that is screwed into the cylinder, and the nut member 30 is slidably and non-rotatably supported in the cylinder. Brake actuator.