JPH0550907A - Automatic brake actuator - Google Patents

Abstract

PURPOSE:To provide an automatic brake device having excellent safety by synthetically controlling a system through an electronic control device having a built-in actuator for an automatic brake in the hydraulic circuit of an anti-skid brake system, and providing the system with a built-in mechanism to prevent the pull of a wheel at the time of actuating an automatic brake. CONSTITUTION:When an electronic control device issues a signal on car body speed and a distance between cars going in the same direction, two position changing over valves 30, 31 severally change over from positions D,F to positions E,G to supply high pressure braking fluid from an accumulator 27 to an automatic brake actuator 5, and the flow passage of the braking fluid is therefore changed over to supply the braking fluid to a wheel cylinder W/C through a three position changing over valve 6 for automatically braking wheels. Pipes formed in two systems are mutually connected through an ordinary balancer to dissolve the difference of fluid pressure acting on the automatic brake actuator.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic brake actuator for incorporating an automatic brake device capable of automatically controlling a traveling speed of a vehicle into an antiskid brake system.

[0002]

2. Description of the Related Art In recent years, in order to ensure the safety of vehicle traveling as well as the accelerator operation by the driver of the traveling speed of the vehicle, the vehicle brake is automatically activated when the inter-vehicle distance becomes shorter than a reference distance. Vehicle automatic brake control methods have been proposed. An example of such a vehicle automatic brake control method is described in Japanese Patent Application Laid-Open No. 62-71727. The present invention operates an engine brake or a normal brake based on a comparison result of a reference distance determined from a traveling speed of a vehicle and a separation distance to an object in front of the vehicle to execute braking of the vehicle. The execution of the braking is canceled based on the comparison result of the reference traveling speed determined from the traveling speed of the vehicle and the traveling speed of the vehicle during the braking.

Further, in order to ensure the safety of vehicle running, an anti-skid brake system has been proposed in which the braking force can be optimally controlled according to the friction coefficient of the road surface. An example of such an anti-skid system is described in JP-A-58-122246. In this anti-skid brake system, if the wheels show a tendency to lock when the vehicle is suddenly stepped on by rapidly depressing the brake pedal while the vehicle is running, the electronic control unit sends a signal to the brake pressure control valve to keep the braking force of the wheels constant. The brake pressure control valve is controlled to hold or release the brake pressure. By the control of the brake pressure control valve, the lock tendency of each wheel is released, so that the vehicle can be decelerated or stopped in a stable state.

[0004]

However, each of the above-described vehicle automatic brake control means and anti-skid brake system functions independently, and these devices are combined to form a compact and high-performance device. Has not been proposed to date. Therefore, the present invention makes it possible to comprehensively control the system by an electronic control unit by incorporating an actuator for automatic braking in the hydraulic circuit of a conventional anti-skid brake system, and to provide a compact and high-performance automatic braking device. Is proposed. Further, it is another object of the invention to propose an automatic braking device having high safety by incorporating a mechanism for preventing a one-sided effect of wheels during the automatic braking operation in the system.

[0005]

Therefore, the first technical solution adopted by the present invention is to change the ABS from the master cylinder to the ABS.
An automatic brake device for a vehicle, in which an automatic brake actuator is arranged in a brake piping system leading to a modulator, and when the inter-vehicle distance becomes shorter than a reference distance, the automatic brake actuator is automatically operated to apply a brake to a vehicle. The automatic brake actuator has a cylinder, a piston slidably arranged in the cylinder, and a flow path communicating with a fluid pressure source that acts to move the piston, and the piston is normally a master. The flow path between the cylinder and the wheel cylinder is in communication.When the automatic brake is activated, the piston moves due to the fluid pressure from the fluid pressure source to close the flow path between the master cylinder and the wheel cylinder and generate a predetermined brake fluid pressure. It is an automatic brake actuator characterized by being configured to A second technical solution is to dispose an automatic brake actuator in each of the two brake piping systems from the master cylinder to the ABS modulator so that the automatic brake actuator is automatically operated when the inter-vehicle distance becomes shorter than the reference distance. Is an automatic brake device for a vehicle in which a brake is applied to a vehicle by operating the cylinders, the automatic brake actuators acting to move a cylinder, a piston slidably arranged in the cylinder, and the piston. A flow passage communicating with a fluid pressure source, and a flow passage communicating with the fluid pressure source of each of the automatic brake actuators communicates with each other via an equal pressure generating means, and the piston is normally a master cylinder and a wheel cylinder. The fluid flow from the fluid pressure source is used during automatic braking. An automatic brake actuator characterized in that a piston moves to close a flow path between a master cylinder and a wheel cylinder, and a predetermined brake fluid pressure is generated, and a third technical solution is the above-mentioned. The equal pressure generating means in the second technical solution means is a fluid pressure balancer arranged between two brake piping systems, and the fourth technical solution means uses the automatic brake actuator as a cylinder. This is configured as a tandem type automatic brake actuator composed of a piston slidably arranged in the cylinder, and these are means for solving the problem.

[0006]

When the electronic control unit outputs a signal for activating the automatic brake based on the vehicle speed and the inter-vehicle distance, the two-position switching valves 30 and 31 move from the D position and the F position to the E position, respectively.
The high-pressure brake fluid is supplied from the accumulator 27 to the automatic brake actuator 5 by switching the position to the G position, whereby the automatic brake actuator 5 switches the flow path 58 in the automatic brake actuator 5 and is used as an anti-skid brake system. Brake fluid can be supplied to the wheel cylinder W / C via the pressure control valve 6 to automatically brake the wheels. In addition, in this system, the oil passage extending from the accumulator 27 to the two-position switching valve 30 is used as one system, the automatic brake actuators used in two are combined into one system, and the pipes configured as two systems are known. The hydraulic pressure difference acting on the automatic brake actuator is eliminated by connecting via the balancer 40.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a hydraulic piping diagram of a hydraulic brake device according to a first embodiment of the present invention. FIG. 2 is a detailed sectional view of the automatic brake actuator device. Each valve and hydraulic pump provided in the hydraulic circuit of FIG. 1 are controlled by the electronic control unit ECU shown in the figure, but since control of such a valve is not essential here, Detailed description is omitted.

(Regarding Structure of Anti-Skid Brake System) In FIG. 1, two hydraulic pressure generating chambers are defined in the cylinder body of the tandem master cylinder 1, and a reservoir 2 is provided integrally with the main body 1. ing. Pipe lines 3 and 4 are connected to the two hydraulic pressure chambers, and a hydraulic pressure can be generated in the pipe lines 3 and 4 by depressing a brake pedal.

The conduit 3 connected to one hydraulic chamber is
When the automatic brake is not operated, the tandem master cylinder 1 and the brake pressure control valve 6 are connected to the two brake pressure control valves 6 in the ABS modulator through an automatic brake actuator 5 having a configuration for communicating with each other. 6 is connected to two wheel cylinders W / C (for example, left and right front wheels). The pipe line 4 is connected to the two brake pressure control valves 6 in the ABS modulator via the automatic brake actuator 5 similarly to the hydraulic circuit described above, and the brake pressure control valve 6 includes two wheel cylinders W / C (for example, left and right rear wheels). )It is connected to the. The brake pressure control valve 6 is configured as an A, B, C3 port 3 position switching valve. The details of the automatic brake actuator will be described later.

Each brake pressure control valve 6 is connected to a reservoir 8 via a pipe 7, and the reservoir 8 is connected to a motor M.
Check valve 10 at the suction port of hydraulic pump 9 driven by
Connected through. The discharge port of the hydraulic pump 9 is connected to the damper 12 and the automatic brake actuator 5 via the check valve 11. Further, the brake pressure control valve 6 is provided with a check valve 13 for releasing the brake fluid.

(Operation of Anti-Skid Brake System) Under the above-mentioned structure, the operation mode of the anti-skid brake system will be described by focusing on one wheel. When the vehicle is running, the brake pedal is suddenly depressed to suddenly brake. If the wheels in
Controls the S modulator. That is, when the electronic control unit determines that the brake pressure should be held first, it sends a signal to the brake pressure control valve 6 corresponding to the wheel to switch the brake pressure control valve to the B position, and keeps the braking force of the wheel constant. .. If the electronic control unit determines that it is not enough to keep the brake pressure constant and the brake pressure should be relaxed, the brake pressure control valve 6 is switched to the C position, and the brake in the wheel cylinder W / C of the wheel is braked. The liquid is discharged to the reservoir 8 through the brake pressure control valve 6 and the pipe 7, and the brake is released. The brake fluid discharged to the reservoir 8 is immediately sucked by the hydraulic pump 9, and the discharged brake fluid from the hydraulic pump 9 is used for re-pressurization by the position A of the brake pressure control valve 6 via the damper 12.
Alternatively, it is returned to the tandem master cylinder 1 via the automatic brake actuator 5 and the conduit 3 or 4. As a result, the locked state of the wheel exhibiting the locking tendency is released, and the vehicle is decelerated or stopped in a stable state.

(Constitution of automatic braking system)
The automatic brake system is a system for operating the automatic brake actuator 5, and has the following configuration. In FIG. 1, the reservoir 21 is connected to a suction port of a hydraulic pump 25 via a pipeline 23, and the discharge port of the hydraulic pump 25 is connected to an accumulator 27 as a fluid pressure source via a check valve 26. Has been done. The accumulator 27 is connected via a conduit 29 to a D, E2 position switching valve 30 functioning as a power supply valve, and the two-position switching valve 30 is connected via a conduit 33 to the aforementioned automatic brake actuator 5. Further, the circuit 33 is connected to the reservoir 21 via an F, G2 position switching valve 31 and a relief valve 32 which function as pressure reducing valves arranged in parallel. The two-position switching valves 30 and 31 cut off communication with the accumulator 27 when the automatic braking system is inactive, and connect the automatic brake actuator 5 to the reservoir 21. The position switching valves 30 and 31 are switched from the D position and the F position to the E position and the G position, respectively, so that high-pressure fluid can be supplied from the accumulator 27 to the automatic brake actuator 5. The relief valve 32 has a function of returning a part of the high-pressure hydraulic pressure to the reservoir 21 when an unexpected high-pressure hydraulic pressure is generated in the hydraulic circuit to the automatic brake actuator.
Thereby, damage such as breakage of the device can be prevented.

The accumulator 27 is a relief valve 22.
It is connected to the reservoir 21 via the, and when the pressure of the accumulator 27 becomes higher than a predetermined value, the brake fluid is returned from the relief valve 22 to the reservoir 21. Further, a pressure detecting means 28 is provided in a conduit 29 between the accumulator 27 and the two-position switching valve 30, and the pressure detecting means 28 detects this pressure when the pressure in the conduit 29 becomes a predetermined value or less. By driving the motor M and operating the hydraulic pump 25, a predetermined hydraulic pressure can be constantly accumulated in the accumulator 27. The accumulator 27 as a fluid pressure source may be any as long as it can actuate the piston in the automatic brake actuator to generate a predetermined brake fluid pressure.

Therefore, when the electronic control unit outputs a signal for actuating the automatic brake, the two-position switching valves 30, 31 are selected.
Are switched from the D position and the F position to the E position and the G position, respectively, and the high-pressure brake fluid is supplied from the accumulator 27 to the automatic brake actuator 5.
The automatic brake actuator 5 switches the flow path in the automatic brake actuator as described later, and supplies the brake fluid to the wheel cylinder W / C via the brake pressure control valve 6 as the A, B, C3 port 3 position switching valve, It will be possible to brake the wheels automatically.

(Construction of Automatic Brake Actuator 5) The automatic brake actuator 5 connects the tandem master cylinder 1 and the brake pressure control valve 6 when the automatic brake does not operate, and when the automatic brake operates, the accumulator 27 outputs The brake fluid pressure shuts off the communication between the tandem master cylinder 1 and the brake pressure control valve 6, and at the same time, a predetermined brake fluid pressure is applied to the brake pressure control valve 6.
It has a function of being able to supply to the wheel cylinder W / C via the., And its configuration will be described in detail below by focusing on one automatic brake actuator 5.

The automatic brake actuator 5 has a flow path 52 communicating with the wheel cylinder W / C at one end of the cylinder.
And a flow path 54 communicating with the accumulator 27 via the two-position switching valve 30 of the automatic braking system on the other end side.
Further, between these flow paths 52 and 54, there is a flow path 53 which is connected to the tandem master cylinder 1 via the conduit 3 or 4 of the anti-skid brake system. A piston 55, which is normally biased rightward in the figure by a spring 56, is slidably disposed in the cylinder body 51. A seal member 5 is provided on the outer periphery of the piston 55.
7, 57 'are attached, a seal member 57 is arranged on the outer circumference of the piston in the cylinder between the flow paths 52 and 53, and is in the cylinder between the flow paths 53 and 54. A seal member 57 'is arranged on the outer circumference of the piston. In addition, the piston 55 has a flow passage 53 and a flow passage 5.
A channel 58 communicating with the channel 2 is formed.
A ball valve 59 is disposed opposite to the valve 8. Ball valve 5
9 is normally urged to the right in the figure by the sprinkle 61, but the passage 58 is not closed by the stopper provided on the guide rod 60 of the ball valve 59. The path 58 is open.

Therefore, when the automatic brake is not operated, the brake fluid pressure generated by the master cylinder is applied to the flow path 5.
Wheel cylinder W / C through 3, channel 58, channel 52
Will be supplied as is. Further, when the fluid pressure is supplied from the accumulator 27 into the automatic brake actuator during the automatic braking operation, the piston 55 in the automatic brake actuator 5 is moved leftward in the figure by this fluid pressure. The flow passage 5 is generated by the initial operation of the piston 55.
8 is closed by the ball valve 59, and when the brake fluid is continuously supplied to the automatic brake actuator in this state, the piston 55 further moves to the left in the drawing against the biasing force of the spring 56. By this movement of the piston 55, the brake fluid in the fluid chamber S partitioned by the piston 55 and the automatic brake actuator is discharged from the flow path 52, and passes through the brake control valve used as the anti-skid brake system to the wheel cylinder W / By supplying the brake fluid to C, the wheels can be automatically braked. The state at this time fulfills the same function as that of the known master cylinder, and the circulation of the brake fluid to the tandem master cylinder 1 is almost negligible. As described above, when the fluid pressure from the accumulator 27 is supplied from the flow path 54 to the automatic brake actuator, the wheels are automatically braked. When an emergency occurs during the automatic brake operation and it becomes necessary to apply a sudden brake, when the brake pedal is depressed, the high-pressure brake fluid generated in the master cylinder deforms the lip of the seal member 57 and the flow path 52. The braking force can be further increased by flowing into. Also,
As a means to operate the automatic brake actuator,
In the above example, the case where the fluid pressure from the accumulator is used has been described, but a negative pressure of the engine or a booster mechanism can also be used.

(About the operation of the automatic braking system)
With the above configuration, when the electronic control unit determines that the distance to the object in front of the vehicle is less than or equal to a predetermined value and the electronic control unit outputs a signal to activate the automatic brake, the two-position switching valves 30, 3
1 is switched from the D position and the F position to the E position and the G position, respectively, and high-pressure brake fluid is supplied from the accumulator 27 to the automatic brake actuator 5, so that the wheels can be automatically braked as described above. When the wheels are locked in this state, the anti-skid brake system is activated to avoid the locked wheels. At this time, the brake fluid returned from the hydraulic pump moves the piston 55 in the automatic brake actuator to the right in the figure, but the fluid pressure generated in the conduit 33 is returned to the reservoir via the relief valve 32. be able to. Further, the strength of the automatic braking can be controlled by controlling the two-position switching valves 30 and 31 by the electronic control device.

As described above, in the automatic brake device of the first embodiment, when the electronic control device outputs the signal for operating the automatic brake based on the vehicle speed and the inter-vehicle distance, the two-position switching valves 30 and 31. , D position, F respectively
Accumulator 2 switching from position to E position and G position
A high-pressure brake fluid is supplied from 7 to the automatic brake actuator 5, whereby the automatic brake actuator 5 switches the flow path 58 in the automatic brake actuator 5 and is used as an anti-skid brake system. Brake fluid can be supplied to the wheel cylinder W / C via the switching valve to automatically brake the wheels.

By the way, in the first embodiment, the oil passage from the accumulator 27 to the two-position switching valve 30 is branched, and the oil passage from the two-position switching valve 30 to the automatic brake actuator 5 has two systems. Since they are provided separately, one-sided braking may occur if a difference occurs in the brake fluid pressure acting on the automatic brake actuator 5. That is, the hydraulic pressure after the two-position switching valve 30 may differ depending on the operating state of the two-position switching valve 30, which may cause a difference in the brake hydraulic pressure acting on the automatic brake actuator 5. For this reason,
In the second, third and fourth embodiments of the present invention, in order to avoid such a phenomenon, an equal pressure generating means for equalizing the fluid pressure acting on the automatic brake actuator is adopted to prevent the one-sided effect of the brake. ing.

First, the second embodiment will be described with reference to FIG. 3. In this system, the oil passage from the accumulator 27 to the two-position switching valve 30 is set as one system, and the two-position switching valve 30 is used.
After that, the oil passage is branched so that the hydraulic pressure can be supplied to the automatic brake actuator 5. Further, a check valve 32 'is provided for returning the high pressure oil in the oil passage to the accumulator. The check valve 32 'has the same function as the relief valve 32 shown in FIG. With this configuration, in the second embodiment, the piping system of the automatic brake system is simplified as compared with that in the first embodiment, and the hydraulic pressure supplied to the automatic brake actuator is the same pressure, so that the brake You can avoid one-sided effects.

Next, the third embodiment will be described with reference to FIG. 4. As can be understood from FIG. 4, in this system, the two automatic brake actuators used in the second embodiment are combined. This not only avoids the one-sided effect of the brake, but also further simplifies the configuration. The automatic brake actuator 5'is configured as a tandem type in which the two automatic brake actuators described above are arranged in series.

Further, a fourth embodiment will be described with reference to FIG. 5. In this system, the two-position switching valve 3 of the first embodiment is used.
Pipes configured as two systems after 0 are connected to each other through a known balancer 40 to eliminate the hydraulic pressure difference generated in the two systems. With this configuration, it is possible to easily avoid the one-sided effect of the brake simply by connecting the balancer to the pipe of the first embodiment. The operation of the automatic braking system of each of the above-described embodiments is similar to that of the first embodiment, and therefore its explanation is omitted.

As described above, in the second to fourth embodiments, there is no difference in the brake fluid pressure acting on the automatic brake actuator 5, it is possible to prevent the occurrence of one-sided braking, and the safety is further improved. Will increase.

[0025]

As described in detail above, according to the present invention, an actuator for automatic braking is incorporated in the hydraulic circuit of the conventional anti-skid brake system so that the system can be comprehensively controlled by the electronic control unit. Therefore, a compact and high-performance automatic braking device can be obtained. Further, in the present invention, in order to prevent the occurrence of one-sided braking effect, the piping system acting on the automatic brake actuator is set to one system, the hydraulic balancer is inserted in the oil passage, and the like. It is possible to obtain an excellent effect such as obtaining an automatic brake device having high efficiency.

[Brief description of drawings]

FIG. 1 is a hydraulic piping diagram of a hydraulic brake device according to a first embodiment of the present invention.

FIG. 2 is a detailed cross-sectional view of the automatic brake actuator device of the present invention.

FIG. 3 is a hydraulic piping diagram of a hydraulic brake device according to a second embodiment of the present invention.

FIG. 4 is a hydraulic piping diagram of a hydraulic brake device according to a third embodiment of the present invention.

FIG. 5 is a hydraulic piping diagram of a hydraulic brake device according to a fourth embodiment of the present invention.

[Explanation of symbols]

 1 Tandem Master Cylinder 2 Reservoir 5 Automatic Brake Actuator 5'Tandem Type Automatic Brake Actuator 6 3 Port 3 Position Switching Valve 8 Reservoir 9,25 Hydraulic Pump 12 Damper 27 Accumulator 28 Hydraulic Pressure Detection Device 30, 31 2 Position Switching Valve 32 Relief Valve 32 'Check valve 40 Balancer

Claims (4)

[Claims] 1. An automatic brake actuator is arranged in a brake piping system from a master cylinder to an ABS modulator, and when the inter-vehicle distance becomes shorter than a reference distance, the automatic brake actuator is automatically operated to apply a brake to a vehicle. In the automatic brake device for a vehicle, the automatic brake actuator includes a cylinder, a piston slidably arranged in the cylinder, and a flow path communicating with a fluid pressure source that acts to move the piston. The piston always communicates with the flow path between the master cylinder and the wheel cylinder, and when the automatic brake is activated, the piston moves due to the fluid pressure from the fluid pressure source so that the flow path between the master cylinder and the wheel cylinder is established. It is characterized in that it is configured to generate a predetermined brake fluid pressure when closed. Automatic brake actuator to do. 2. An automatic brake actuator is arranged in each of two brake piping systems from a master cylinder to an ABS modulator, and when the inter-vehicle distance becomes shorter than a reference distance, the automatic brake actuator is automatically operated to drive the vehicle. An automatic brake device for a vehicle in which a brake is operated, wherein each automatic brake actuator communicates with a cylinder, a piston slidably arranged in the cylinder, and a fluid pressure source that acts to move the piston. The flow passage communicating with the fluid pressure source of each of the automatic brake actuators is communicated via the equal pressure generating means, and the piston always connects the flow passages of the master cylinder and the wheel cylinder. The pistons move due to the fluid pressure from the fluid pressure source when the brakes are in communication Then, the automatic brake actuator is configured to close a flow path between the master cylinder and the wheel cylinder and generate a predetermined brake fluid pressure. 3. The automatic brake actuator according to claim 2, wherein the equal pressure generating means is a fluid pressure balancer arranged between two brake piping systems. 4. An automatic brake actuator is arranged in each of two brake piping systems from a master cylinder to an ABS modulator, and each automatic brake actuator is automatically operated when the inter-vehicle distance becomes shorter than a reference distance. An automatic brake device for a vehicle in which a brake is operated, wherein each automatic brake actuator is configured as a tandem automatic brake actuator including a cylinder and a piston slidably arranged in the cylinder. At the same time, it has a flow path that communicates with a fluid pressure source that acts to move the piston, and the piston normally communicates with the flow paths of the master cylinder and the wheel cylinder of the two systems. The piston moves due to the fluid pressure from the fluid pressure source The flow path between the master cylinder and the wheel cylinder is closed and the specified brake fluid pressure is set to 2
Automatic brake actuator characterized by being configured to occur in the brake piping of the system