JPH0558943B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an improvement in a braking device for a vehicle that can safely stop a vehicle with good directional stability while automatically adjusting the braking force of the wheels.

(Prior Art) Conventionally, as a braking device for this type of vehicle, for example, as disclosed in Japanese Patent Publication No. 56-8777,
A front wheel brake system that applies hydraulic pressure generated by a master cylinder to the front wheel cylinder based on the brake pedal operation, and a rear wheel brake system that applies hydraulic pressure from a separate pressure source to the rear wheel cylinder. and a wheel load detection means for detecting the loads of the front and rear wheels respectively, and an ideal braking fluid that receives the output of the wheel load detection means so that the front and rear wheels simultaneously shift to the lock state according to the load state of the front and rear wheels. a calculation unit that calculates a pressure distribution curve; and a calculation unit that receives the output of the calculation unit and calculates the hydraulic pressure from the pressure source of the rear wheel brake system to the rear wheel cylinder based on the ideal brake pressure distribution curve on the rear wheel side. By providing a hydraulic pressure control means that reduces the pressure so that the brake fluid pressure is maintained, and adjusting the braking force so that the front and rear wheels begin to lock simultaneously when braking the vehicle, the vehicle can be safely operated with good directional safety. There are known devices that allow the engine to stop.

(Problems to be Solved by the Invention) However, with the above conventional system, braking is not performed unless the driver depresses the brake pedal. Automatic braking cannot be applied to the vehicle regardless of whether the driver depresses the brake pedal. In addition, since the front wheel brake system and the rear wheel brake system are separate systems, if the pressure source of the rear wheel brake system becomes inoperable due to a failure etc., when the brake pedal is depressed, the master cylinder Although braking force is applied to the front wheels based on the generated hydraulic pressure, no braking force is applied to the rear wheels.

Therefore, for example, in a vehicle braking system that is equipped with a separate pressure source as described above, when the driver depresses the brake pedal, or even when the driver does not depress the brake pedal, the fluid generated by the pressure source is automatically The brake pedal is configured to apply hydraulic pressure based on pressure to the wheel cylinder of each wheel, and is configured to increase or decrease the hydraulic pressure to the wheel cylinder of each wheel so that the front and rear wheels begin to lock at the same time. It is conceivable that both brake control by the driver, in which the vehicle is braked based only on the depression of the brake pedal, and automatic brake control, in which the vehicle is braked regardless of whether or not the brake pedal is depressed, can be performed.

However, in the above idea, since the configuration is such that hydraulic pressure based on the hydraulic pressure generated by a pressure source is applied to the wheel cylinder of each wheel, it is possible to automatically brake the vehicle even when the brake pedal is not depressed. , in the event of a failure in which hydraulic pressure is not generated from the pressure source, even if the driver depresses the brake pedal,
This results in the frustration that no operating force is applied to the front wheels and rear wheels.

The present invention has been made in view of these points,
The purpose of this is to use the hydraulic pressure generated by the pressure source to apply braking force to the front and rear wheels with an ideal distribution of brake hydraulic pressure, even when the driver does not press the brake pedal. In addition to automatically stopping the vehicle safely with good directional stability, in the event of an emergency when the above pressure source becomes inoperable,
The hydraulic pressure generated in the master cylinder based on the driver's depression of the brake pedal is applied to the wheel cylinders of each wheel to ensure braking force for the vehicle, making the vehicle safe even in an emergency when the pressure source fails. Moreover, the purpose is to stop it reliably.

(Means for Solving the Problems) In order to achieve the above object, in the present invention, when the pressure source is normal, the hydraulic pressure generated by the pressure source is used to generate braking force on the wheels, but when the pressure source is malfunctioning, the braking force is generated on the wheels. , the braking force is generated at the wheels based on the hydraulic pressure generated in the master cylinder by the driver's depression of the brake pedal.

That is, the solution of the present invention, as shown in FIG.
A brake control actuator 20 is interposed in the hydraulic pressure passage 5, and a pressure source 12 for applying hydraulic pressure to the brake control actuator 20 is provided. Normally, when hydraulic pressure is available, the hydraulic pressure from the pressure source 12 closes the hydraulic passage 5 to cut off the hydraulic pressure from the master cylinder 2 to the wheel cylinders 4, and the pressure source 1
The hydraulic pressure based on the hydraulic pressure generated in step 2 is applied to wheel cylinder 4.
On the other hand, in the event of a failure when the hydraulic pressure from the pressure source 12 is not applied, the hydraulic pressure passage 5 is configured to be communicated. Further, wheel load detection means 40 for detecting the load applied to the wheel 3 and a controller 34 for controlling the hydraulic pressure from the pressure source 12 to the brake control actuator 20 are provided, and the controller 34 includes the wheel load detection means 40 for detecting the load applied to the wheel 3. 40 receives an output signal from the pressure source 12 and compares the hydraulic pressure acting on the wheel cylinder 4 with the hydraulic pressure of the hydraulic pressure setting means 44. This configuration includes adjustment means 45 for adjusting the hydraulic pressure supplied to the brake control actuator 20.

(Function) With the above configuration, in the present invention, when the pressure source is normal, when the driver depresses the brake pedal or when automatic brake control is required, the master cylinder 2 is used to control the front and rear wheels 3. While the hydraulic pressure to the cylinder 4 is cut off by the brake control actuator 20, hydraulic pressure based on the hydraulic pressure generated by the hydraulic pump 12 is supplied to the wheel cylinders 4 of the front and rear wheels 3, and this hydraulic pressure is applied to each wheel. Since the adjustment means 45 increases or decreases the braking fluid pressure to the set value according to the load applied to the brake fluid, the front and rear wheels 3 simultaneously shift to the locked state, and the vehicle stops safely with good directional stability. do.

On the other hand, in the case of an emergency when the pressure source 12 becomes inoperable, the hydraulic pressure passage 5 is communicated with the hydraulic pressure passage 5, so that when the driver depresses the brake pedal, the pressure generated in the master cylinder 2 The hydraulic pressure acts on the wheel cylinders 4 of the front and rear wheels 3 through the hydraulic pressure passage 5 without being interrupted, and the braking force of the front and rear wheels 3 is ensured, so that the vehicle is stopped safely and reliably.

(Example) Hereinafter, an example of the present invention will be described based on the drawings from FIG. 2 onwards.

FIGS. 2 and 3 show an embodiment applied to a braking device for a vehicle equipped with an anti-skid system that prevents wheels from skidding during sudden braking.
In the figure, 1 is a brake pedal, and 2 is a master cylinder that converts the depression force of the brake pedal 1 into hydraulic pressure corresponding to the depression force.

In addition, 3a to 3d are front, rear, left and right wheels,
Each of the wheels 3a to 3d is provided with a wheel cylinder 4a to 4 which receives hydraulic pressure and applies braking force to the wheel.
d is provided. The master cylinder 2 and each of the wheel cylinders 4a to 4d are connected via hydraulic pressure passages 5a to 5d, respectively, and apply control force to each wheel 3a to 3d based on the depression of the brake pedal 1. It is done like this.

Furthermore, 10 is an anti-skid device,
The anti-skid device 10 has a reservoir 1 therein.
A hydraulic pump 12 that supplies one fluid, and an accumulator 13 that stores the hydraulic pressure from the hydraulic pump 12.
The hydraulic pressure from the accumulator 13 is received from the master cylinder 2 to the wheel cylinders 4a to 4d.
The anti-skid modulator 14 is provided in the hydraulic pressure passages 5a-5d from the master cylinder 2 to the wheel cylinders 4a-4d, respectively. four pressure regulating valves 15 that open and close each of the hydraulic pressure passages 5a to 5d; a switching valve 16 that switches to allow the return of hydraulic pressure to
By controlling the opening and closing of each hydraulic pressure passage 5a to 5d by each pressure regulating valve 15, the hydraulic pressure acting on each wheel cylinder 4a to 4d is increased or decreased to prevent skidding of each wheel 3a to 3d. It is done like this.

In the hydraulic pressure passages 5a to 5d upstream of the pressure regulating valve 15 of the anti-skid device 10, there is provided a brake control actuator 2 as a feature of the present invention.
0a to 20d are interposed. The respective brake control actuators 20a to 20d have the same configuration, and as shown in FIG.
The brake control actuator 20c includes a piston 22 that slides from side to side in the drawing within the housing 21, and a compressed spring 23 that urges the piston 22 to the right in the drawing. A chamber 24 and a pressure chamber 25 corresponding to the spring chamber 24 are provided.
The hydraulic pressure passage 5 on the wheel cylinder 4c side is located at the left end of the wheel cylinder 4c side.
A hydraulic pressure outlet 24b to c is opened, respectively. Further, the pressure chamber 25 has a pressure introduction passage 2.
The hydraulic pump 12 of the anti-skid device 10 is connected as a pressure source through the anti-skid device 6, and the hydraulic pressure from the hydraulic pump 12 can act on the pressure chamber 25. The piston 22 is moved by the spring 23 due to the hydraulic pressure from the hydraulic pump 12.
The piston 22 moves to the left in the figure against the urging force of the piston 22 and closes the hydraulic pressure passage 5 by closing the hydraulic pressure inlet 24a, thereby reducing the hydraulic pressure from the master cylinder 2 to the wheel cylinder 4c. cut off,
After that, the movement of the piston 22 causes the spring chamber 24 to
The hydraulic pressure in the spring chamber 24 is supplied to the wheel cylinder 4c from the hydraulic pressure outlet 24b, thereby increasing the hydraulic pressure to the wheel cylinder 4c. On the other hand, when the hydraulic pump 12 fails and no hydraulic pressure is generated from the hydraulic pump 12, the piston 22 is positioned at the right end position in the figure by the spring 23,
The hydraulic pressure inlet 24a and the hydraulic pressure outlet 24b are communicated with each other, and the hydraulic pressure passage 5 is communicated with each other, so that the hydraulic pressure of the master cylinder 2 is applied to the wheel cylinder 4c.

Also, a pressure introduction passage 2 from the hydraulic pump 12 to the brake control actuators 20a to 20d is provided.
6 and 26 each have a front wheel 3 consisting of an opening valve.
First control valves 30, 30 are interposed for the rear wheels 3c, 3d and the first control valves 30, 30 are branched from the pressure introduction passages 26, 26 downstream of the first control valves 30, 30 and connected to the reservoir 12. Second control valves 32, 32 for the front wheels and for the rear wheels, which are respectively on-off valves similar to the above, are interposed in the communicating pressure discharge passages 31, 31, and both control valves 30, 3
2 are each connected to a control unit 33 equipped with a CPU etc. so as to be able to send and receive signals, and the control unit 33 controls the first and second
A controller 34 is configured to control the hydraulic pressure from the hydraulic pump 12 to the brake control actuators 20a to 20d by controlling the opening and closing of the control valves 30 and 32.

Further, as shown in FIG. 3, 40 indicates each wheel 3a.
41 is an input hydraulic pressure sensor that detects the hydraulic pressure generated in the master cylinder 2. 42 is an input hydraulic pressure sensor for each wheel cylinder 4a to 4d. An output hydraulic pressure sensor 43 detects the hydraulic pressure, and a brake operation switch 43 detects a depression operation of the brake pedal 1. These output signals are input to the control unit 33.

Next, the controller 34 controls the brake control actuators 20a to 20 from the hydraulic pump 12.
Control of the hydraulic pressure to 20d will be explained based on FIG. 4. First, input the wheelbase and center of gravity of the vehicle that were previously measured in S1, and
In S2, input the tire radius, brake effective radius, brake factor, and wheel cylinder system for the front and rear wheels in advance. And in S3 4
input the axle load signals from the axle load sensors 40,
After calculating the left and right average axle loads of the front wheels and rear wheels based on each axle load signal in S4,
In S5, the average left and right axle loads of the front and rear wheels and the above
Based on the signals input in S1 and S2, an ideal braking hydraulic pressure distribution map is read out from the control unit 33, which is determined in advance according to the load condition of the front and rear wheels so that the front and rear wheels simultaneously shift to the locked state. As described above, in response to the output signal from the axle load sensor 40, the front and rear wheels 3
A hydraulic pressure setting means 44 is configured to set the braking hydraulic pressures a to 3d.

Next, in S6, press brake operation switch 4.
While inputting the brake operation signal from 3,
After inputting the master cylinder generated hydraulic pressure signal from the input hydraulic pressure sensor 41 in S7, in S8 the front wheel side ideal brake hydraulic pressure is distributed according to the master cylinder generated hydraulic pressure Po based on the ideal brake hydraulic pressure distribution map. Read out PF and rear wheel ideal brake fluid pressure PR, and set the actual brake fluid pressure on the front and rear wheels to the ideal brake fluid pressures PF and PR, respectively.
First and second control valves 30, 32
The hydraulic pressure from the hydraulic pump 12 to the brake control actuators 20a to 20d is adjusted by controlling opening and closing. After that, in S9, the wheel cylinder generated hydraulic pressure signals from the output hydraulic pressure sensors 42 on the front and rear wheels are input, and in S10, the deviation PF - PF1 between the ideal brake hydraulic pressure PF on the front wheel side and the actual brake hydraulic pressure PF1. And the ideal brake fluid pressure PR and actual brake fluid pressure PR on the rear wheel side.
It is determined whether or not the difference PR-RR1 with respect to 1 is less than the allowable value a, and if NO, the difference PR-RR1 is greater than the allowable value a, then the process returns to S8 and the brake control actuator 20a is activated from the hydraulic pump 12 in order to make the difference PR-RR1 less than the allowable value a. ~2
While adjusting the hydraulic pressure to 0d, below the tolerance value a
If YES, it is determined that the ideal brake fluid pressure distribution has been achieved and the process ends. As described above, the hydraulic pressures PF1 and PR1 acting on the front wheel side and rear wheel side wheel cylinders 4a to 4d are adjusted to the hydraulic pressure setting means 4, respectively.
Adjustment means 45 is configured to compare the set hydraulic pressures PF and PR of No. 4 and adjust the hydraulic pressure supplied from the hydraulic pump 12 to the brake control actuators 20a to 20d so that the difference between the two hydraulic pressures is less than an allowable value. It consists of

Further, as shown in FIG. 22, the control unit 33 is inputted with an output signal of a braking torque sensor 46 that detects the braking torque of each wheel 3a to 3d, and the difference between the braking torque of the left and right wheels is inputted to the control unit 33. If the pressure exceeds the allowable range, the hydraulic pressure to the wheel cylinders 4a to 4d is adjusted to be uniform based on the brake control actuators 20a to 20d. This is designed to suppress the generated yaw moment and improve braking stability.

Furthermore, the control unit 33 includes:
Output signals from a wheel speed sensor 47 that detects the speed of the wheels 3a to 3d, respectively, and an accelerator operation switch 48 that detects the depression of the accelerator pedal are inputted, and an intake sensor installed in the intake passage 49 of the engine is inputted. An engine control actuator 51 is connected to control the opening and closing of a throttle valve 50 for air volume control, and brake control actuators 20a to 20d and By controlling the engine control actuator 51, starting on a low μ road is facilitated.

In addition, the control unit 33 includes:
A braking effect adjustment dial 54 that variably sets the ratio of the hydraulic pressure of the wheel cylinders 4a to 4d to the hydraulic pressure of the master cylinder 2 (boosting ratio), and a braking effect adjustment dial 54 that is provided around the steering wheel in the vehicle interior and manually operated in place of the brake pedal 1. Each output signal from a manual brake operation switch 56 that detects the amount of manual brake operation to be performed is inputted, and the boost ratio of the brake force is set to a large value to reduce the pressing force on the brake pedal 1. The driver's fatigue is reduced by braking the vehicle by manually operating the manual brake instead of pressing the brake pedal.

The control unit 33 also includes a speedometer 60 that measures the vehicle speed, an obstacle sensor 61 that detects obstacles in front of the vehicle, and a vehicle speed setting switch 62 that sets the vehicle speed at which you want the vehicle to travel at a constant speed.
Each output signal from the following distance setting switch 63 for setting the desired following distance is input, and when traveling at a constant speed or at a constant following distance, even if the throttle valve is fully closed, the above-mentioned constant speed traveling state or constant When the following distance cannot be maintained or when a vehicle (obstacle) that changes lanes suddenly appears in front of the vehicle, the brake control actuators 20a, 20
By forcibly generating hydraulic pressure in the wheel cylinders 4a to 4d based on d and applying braking force,
It is designed to improve controllability and safety.

Furthermore, the control unit 33 includes:
A brake holding hydraulic pressure setting switch 64 that sets the hydraulic pressure of the wheel cylinders 4a to 4d to automatically maintain the vehicle stopped state when the vehicle is stopped, and a parking brake operating switch 66 that detects the pulling operation of the parking brake lever. When the output signal is input and the vehicle is stopped, the wheel cylinders 4a~
The hydraulic pressure of 4d is applied to the brake control actuator 20a.
-20d, the automatic transmission automatically maintains the set value of the brake holding hydraulic pressure setting switch 64, and at the time of subsequent start-up, releases the holding of the hydraulic pressure set value based on the release operation of the parking brake lever. It is designed to prevent so-called creep starting, where the vehicle gradually moves forward, and to facilitate starting on a slope.
In FIGS. 1 and 2, 80 is a motor that drives the hydraulic pump 12 of the anti-skid device 10. In addition, in Fig. 2, 81 is the master cylinder 2.
It is a proportioning valve provided immediately downstream of the master cylinder 2 and the rear wheels 3c, 3d.
By controlling the increase in hydraulic pressure to the wheel cylinders 4c and 4d to a predetermined hydraulic pressure value or higher, the brake hydraulic pressure distribution between the front and rear wheels is made to approximate the ideal brake fluid distribution according to the loading condition of the vehicle. be.

Therefore, in the above embodiment, when the brake pedal 1 is depressed during normal times when hydraulic pressure is generated from the hydraulic pump 12, the hydraulic pressure setting means 44 of the controller 34 controls the front and rear wheels 3.
An ideal brake hydraulic pressure distribution map corresponding to the loads a to 3d is selected, and the hydraulic pressure from the hydraulic pump 12 to the brake control actuators 20a to 20d is increased or decreased by the adjusting means 45, and the hydraulic pressure is increased or decreased to each brake control actuator 20a. The piston 22 of ~20d moves to the left in FIG.
All hydraulic pressure inlets 24a are closed, and hydraulic pressure from the master cylinder 2 to each wheel cylinder 4a to 4d is cut off, and the front and rear wheels 3a to 3d are
The hydraulic pressure PF1 to the wheel cylinders 4a to 4d of
PR1 is distributed based on the above-mentioned ideal brake fluid pressure distribution map and adjusted to ideal brake fluid pressures PF and PR for the front and rear wheels according to the fluid pressure Po generated in the master cylinder 2. Wheel 3a~
An appropriate braking force is applied to each wheel 3d so that each wheel starts to lock at the same time, and as a result, the vehicle comes to a safe stop with good directional stability.

Furthermore, even when automatic braking is required, if the hydraulic pump 12 is normal, the hydraulic pressure generated by the hydraulic pump 12 will cause all the hydraulic inlets 2 to
4a is closed and the hydraulic pressure passage 5 is closed, and the piston 22 moves to the left in FIG. Since hydraulic pressure is supplied to each of the wheel cylinders a to 4d, automatic braking force is applied to each of the front wheels 3a to 3d, and the vehicle automatically stops safely.

On the other hand, in the case of an abnormality in which the hydraulic pump 12 becomes inoperable, the pistons 22 of each brake control actuator 20a to 20d are positioned at the right end position in FIG. 3, and the hydraulic inlet 24a and hydraulic outlet 24b, and the hydraulic pressure passage 5 is opened, so that when the driver depresses the brake pedal 1, the hydraulic pressure generated in the master cylinder 2 based on this is applied to each brake control actuator 20a to 20a.
0d, and acts on each wheel cylinder 4a to 4d via hydraulic pressure passages 5a to 5d, and each wheel 3
Braking force is applied to points a to 3d, and the vehicle is stopped safely and reliably. Therefore, brake control by the driver and automatic brake control can be performed, and when performing both brake control, it is possible to improve braking stability by distributing ideal brake fluid pressure to the front and rear wheels. Moreover, even when the hydraulic pump 12 is inoperable, the braking force of each wheel 3a to 3d can be ensured, and driving safety can be significantly improved.

Moreover, the brake control actuators 20a to 2
Since the hydraulic pump 12 of the anti-skid device 10 is also used as the pressure source for 0d, the
Cost reduction is possible.

(Effects of the Invention) As explained above, according to the vehicle braking device of the present invention, the brake control actuator interposed in the hydraulic passage between the master cylinder and the wheel cylinder controls the pressure source provided separately to The hydraulic pressure based on the hydraulic pressure generated by the pressure source is used to cut off the hydraulic pressure from the master cylinder to the wheel cylinders, and the hydraulic pressure based on the hydraulic pressure generated by the pressure source is supplied to the wheel cylinders, and the hydraulic pressure of each wheel is The brake fluid pressure is controlled to the ideal brake fluid pressure based on the ideal brake fluid pressure distribution curve according to the load condition of the front and rear wheels, so that the front and rear wheels always begin to lock at the same time.This allows the driver to easily control the brakes with a simple structure. and automatic brake control, and in both brake controls, it is possible to apply brake fluid pressure to the front and rear wheels to always stop the vehicle safely with good directional stability regardless of its loaded state. Even if the pressure source becomes inoperable, the hydraulic pressure generated in the master cylinder can be applied to the wheel cylinders to ensure braking force for the wheels, improving vehicle driving safety in the event of an emergency when the pressure source is out of order. It is possible to significantly improve sexual performance.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the present invention. Figures 2 to 4 show embodiments of the present invention, with Figure 2 being a general schematic diagram, Figure 3 being a major part diagram showing the control system for the left rear wheel, and Figure 4 showing the operation of the controller. It is a figure for explaining. 1...Brake pedal, 2...Master cylinder, 3a-3d...Wheel, 4a-4d...Wheel cylinder, 5a-5d...Hydraulic pressure passage, 12...
Hydraulic pump, 20a to 20d, 20'...brake control actuator, 34...controller,
44...hydraulic pressure setting means, 45...adjustment means.

Claims (1)

[Claims] 1. A hydraulic passage connecting the master cylinder and a wheel cylinder that applies braking force to the wheels, and a brake control actuator interposed in the hydraulic passage;
and a pressure source that applies hydraulic pressure to the brake control actuator, and the brake control actuator closes the hydraulic pressure passage with the hydraulic pressure from the pressure source during normal times when the hydraulic pressure from the pressure source can be applied. The hydraulic pressure from the cylinder to the wheel cylinder is cut off, and hydraulic pressure based on the hydraulic pressure generated by the pressure source is supplied to the wheel cylinder, while the hydraulic pressure passage is communicated in the event of a failure in which the hydraulic pressure from the pressure source is not applied. and a controller configured to control the hydraulic pressure from the pressure source to the brake control actuator. a hydraulic pressure setting means for setting the braking hydraulic pressure of the front and rear wheels in response to an output signal from the hydraulic pressure setting means, and a brake control actuator from the pressure source by comparing the hydraulic pressure acting on the wheel cylinder with the set hydraulic pressure of the hydraulic pressure setting means. A braking device for a vehicle, comprising: an adjusting means for adjusting hydraulic pressure supplied to the vehicle.