JPH1178838A - Braking control device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a braking control device for a vehicle which can prepare for braking control ASR at low cost, by carrying out ASR control by air pressure and hydraulic pressure. SOLUTION: This control device is constituted so that an electronic control unit 35 is input with the information from a vehicle condition detecting means, then monitors the slip of the driving wheels, and when the driving wheels slip at the time of a start, acceleration, etc., of the vehicle, a control valve 10 is opened and air pressure within an air tank 4 is supplied into an air master 9 of the driving wheels side in no time. The air master 9 converts the supplied air pressure into hydraulic pressure and supplies it to a valve device 13. At the same time, the electronic control unit 35 controls the valve device 13 and supplies the hydraulic pressure to wheel cylinders 18 and/or 19 of the slipping driving wheels, and provides them with the braking force, then prevents the slip.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a vehicle brake control device.

[0002]

2. Description of the Related Art An antilock brake system (ABS) is known as a system for preventing a wheel from being locked during traveling braking on a slippery road surface in a vehicle braking control device to secure vehicle directional stability. In addition, when a driving wheel slips (slip) on a low μ road such as a snowy road, a braking force is applied to the driving wheel to prevent the slip, and the starting stability is ensured, and the running stability at the time of starting, accelerating, etc. There is an ASR (Anti-Spin Regulator) as a system for improvement.

Further, as a braking device, an air master (power booster) for reducing the pedaling force by air pressure (compressed air) and a brake valve used for air brake are combined, and the air pressure from the air tank is controlled by the brake valve. There is an air-over-hydraulic brake device that converts the pressure to hydraulic pressure while boosting it with an air master and transmits the hydraulic pressure to the wheel cylinder of each wheel.

[0004]

In the ABS control, when a braking force is applied by depressing a brake pedal, the applied braking force is controlled by releasing, holding, increasing pressure, and the like to lock the wheels. This eliminates the need for a pump motor as a hydraulic pressure source for the braking force. On the other hand, the ASR control is to apply a braking force when a driving wheel slips in a state where no braking force is applied, and therefore requires a braking force generation source (power source). In addition, since a braking force needs to be applied instantaneously when the drive wheel slips, a large amount of brake fluid is required instantaneously, and a large hydraulic pressure generator (pump motor) is required. Large pump motors are heavy and costly, and it is particularly difficult to equip a medium-sized vehicle (such as a two-axis truck) equipped with a hydraulic ABS with the function of brake control ASR.

[0005] Vehicles equipped with an air-over hydraulic brake device (hereinafter referred to as "air-over vehicles") are usually provided with an air master for front wheels and an air master for rear wheels. And the function of the brake control ASR, it is necessary to separately apply a braking force to the left and right drive wheels (rear wheels).
Therefore, three ABS valves (one for the front wheels and one for the left and right driving wheels (rear wheels)) and one air master (the left and right driving wheels (rear wheels) each require an air master). Therefore, an additional air master is required) and one ASR valve for controlling each air master of the driving wheels is newly required, which leads to a significant increase in cost and weight, such as an increase in the capacity of an air tank. There's a problem.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a vehicle brake control device which performs ASR control based on air pressure and oil pressure, and is capable of supporting brake control ASR at low cost.

[0007]

In order to achieve the above object, according to the first aspect of the present invention, the control means inputs information from the vehicle state detecting means, monitors slippage of the drive wheels, and starts the vehicle. When the driving wheel slips during running and running, the on-off valve is opened and the air pressure in the air tank is instantaneously supplied to the booster. The booster converts the supplied air pressure into hydraulic pressure and supplies it to the valve device. At the same time, the control means controls the valve device according to the slip state of the driving wheel to supply a hydraulic pressure to the wheel cylinder of the slipping driving wheel to apply a braking force. Thus, ASR control is performed by air pressure and oil pressure.

[0008] In the invention of claim 2, the control means includes:
In the state where the parking brake force is applied, when the movement of the vehicle is detected by the information from the vehicle state detecting means, the on-off valve is opened to supply the air pressure from the air tank to the booster, and the braking force is applied to the driving wheels. Is given. This prevents the vehicle from moving due to insufficient pulling of the parking brake lever during stopping and parking. At this time, the on-off valve functions as a parking brake auxiliary valve.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be illustratively described in detail below with reference to the drawings. FIG. 1 is a schematic configuration diagram of a braking control device for an air-over vehicle as an embodiment of the present invention. This air-over vehicle is a medium-sized two-axle vehicle in which the rear wheels are drive wheels. In addition, as a vehicle to which this braking control device is applied, an air-over vehicle equipped with a hydraulic type ABS is suitable, but the scope of the invention is not limited to vehicles having the above specifications.

In FIG. 1, a compressor 2 of a braking control device 1 includes an air passage 20, moisture in the air passage 20,
It is connected to an air chamber 4A of an air tank 4 as an air pressure source via an air dryer 3 for removing oil and the like. The air tank 4 includes an air chamber 4A serving as a base reservoir, a front wheel braking air chamber 4B, and a rear wheel braking air chamber 4C.
A is connected to the air chambers 4B and 4C via a 4-way protection valve (hereinafter simply referred to as "valve") 5 and to each auxiliary device (not shown) via an air passage 21. The compressor 2 is driven by an engine (not shown) of the vehicle.

The front wheel braking air chamber 4B is connected to an inlet 6a of the brake valve 6 via an air passage 22, and the rear wheel braking air chamber 4C is connected to an inlet 6b of the brake valve 6 via an air passage 23. Have been. The outlet 6c of the brake valve 6 is connected to a front wheel air master 8 as a booster via an air passage 24. Brake valve 6
6d is connected to an inlet on one side of the double check valve 7 through an air passage 25, and the outlet of the double check valve 7 is connected to the rear wheel air master 9 as a booster.
It is connected to the. The brake valve 6 is connected to the air passages 22 and 2 according to the operation amount (depressed amount) of the brake pedal 6e.
The air pressure is supplied from the air chamber 4B to the air master 8 and from the air chamber 4C to the air master 9, respectively. The air masters 8 and 9 convert the input air pressure into hydraulic pressure and output it.

Control valve (on / off valve) 1 as an on-off valve
Numeral 0 indicates that the inlet is connected to the air passage 21 via the air passage 26, and the outlet is connected to the other inlet of the double check valve 7 via the air passage 27. This control valve 1
No. 0 has a built-in check valve 11 on the inlet side, and allows only the flow of air from the air chamber 4A of the air tank 4 to the double check valve 7. That is, the control valve 10 is connected to the air master 9 for the rear wheels (drive wheels) by bypassing the brake valve 6 from the air tank 4. The control valve 10 is a normally-closed valve, and is controlled to be opened by an electronic control unit (ECU) 35 as control means described later. The control valve 10 is also used as a parking brake auxiliary valve.

The valve device 13 is a control valve portion 14 for braking the front wheels.
And a control valve unit 15 for rear wheel braking. The control valve unit 14 includes a plurality of control valves for controlling the braking force of the left and right front wheels, respectively. And a plurality of control valves for controlling the respective braking forces. The control valve portion 14 for front wheel braking has an inlet connected to the outlet of the front wheel braking air master 8 via an oil passage 28 and an outlet connected to the wheel cylinders 16 and 17 of the left and right front wheels via oil passages 30 and 31. Have been. The control valve portion 15 for rear wheel braking has an oil passage 29 at the entrance.
And is connected to the rear wheel braking air master 9 via the oil passages 32 and 33, and the left and right rear wheel cylinders 1
8 and 19 are connected.

The valve device 13 includes wheel cylinders 16 to 1
The holding, release, and pressure-increasing control of the brake fluid pressure supplied to 9 is possible, and is controlled by the electronic control unit 35 according to the vehicle state. The control valve portions 14 and 15 of the valve device 13 are normally open valves, and are controlled to be closed by an electronic control device 35. The control valve section 14 controls the hydraulic pressure supplied from the air master 8 to the wheel cylinders 16 and 17 individually, and the control valve section 15 controls the hydraulic pressure supplied from the air master 9 to the wheel cylinders 18 and 19.
The hydraulic pressure supplied to each is controlled separately.

The electronic control unit 35 includes a vehicle speed sensor for detecting a vehicle speed, a wheel speed sensor for detecting a wheel speed of each wheel, a clutch pedal stroke sensor, a parking brake (parking brake) lever switch, and the like. Signals are input as vehicle information to detect the state of the vehicle, and control the control valve 10 and the valve device 13 to perform normal braking, ABS control, ASR
Performs control and the like.

The operation will be described below. The air compressed by the compressor 2 is supplied to an air chamber 4A of an air tank 4 after moisture, oil and the like are removed by an air dryer 3, and is supplied via a valve 5 to a front wheel braking air chamber 4B and a rear wheel braking air chamber 4C. , And is supplied to each accessory and the air passage 26 via the air passage 21.

When the brake pedal 6e of the brake valve 6 is depressed during running of the vehicle, the air pressure in the air chamber 4B of the air tank 4 is applied to the air master 8 through the air passage 22, the brake valve 6, and the air passage 24 in accordance with the amount of depression. The air pressure in the air chamber 4C of the air tank 4 is supplied to the air master 9 through the air passage 23, the brake valve 6, the air passage 25, and the double check valve 7.

The air masters 8 and 9 convert the applied air pressure into a corresponding hydraulic pressure to convert each control valve unit 1 of the valve device 13.
4 and 15. The electronic control unit 35 monitors the lock of each wheel at the time of the traveling braking based on a signal from each wheel speed sensor. When each wheel is not locked, the control valve units 14 and 15 of the valve device 13 are opened. To hold. Accordingly, the hydraulic pressure supplied from the air masters 8 and 9 is directly supplied to the wheel cylinders 16 and 17 of the left and right front wheels and the wheel cylinders 18 and 19 of the right and left rear wheels through the control valve portions 14 and 15 and is supplied to the respective wheels. A braking force corresponding to the amount of depression (operation amount) of the brake pedal 6e is applied.

When all the wheels are locked, the electronic control unit 35 controls the control valve units 14 and 15 of the valve unit 13 so that the air master 8 can control the wheel cylinders 16 and 17.
Then, the hydraulic pressure (braking force) supplied from the air master 9 to the wheel cylinders 18 and 19 is controlled such as release, holding, and pressure increase to prevent locking of these wheels. That is, ABS
Perform control.

The electronic control unit 35 receives signals from the respective wheel speed sensors of the left and right rear wheels (drive wheels) to monitor slippage of these rear wheels (drive wheels). When, for example, the rear wheel slips, the control valve 10 is opened and the air pressure in the air chamber 4A of the air tank 4 is instantaneously supplied to the air master 9 via the double check valve 7. The air master 9 generates a large oil pressure in accordance with the air pressure and supplies it to the control valve 15 of the valve device 13 to perform the brake control ASR.

That is, when one of the rear wheels (drive wheels) slips, the electronic control unit 35 opens the control valve 10 and controls the control valve unit 15 of the valve device 13 to slip. When a braking force is applied by supplying hydraulic pressure to the wheel cylinders of the driving wheels, and when both wheels are rotating unequally, the control valve 10 is opened and the rotation of these two wheels is set to the same rotation speed. The control valve unit 15 is controlled to supply a hydraulic pressure to each of the wheel cylinders 18 and 19 to apply a braking force, thereby preventing the drive wheels from slipping.

The electronic control unit 35 operates the wheel cylinders 18 and 19 of the rear wheels (drive wheels) when it detects that the vehicle is moved due to insufficient pulling of the parking brake (parking brake) lever when the vehicle is stopped or parked. Then, the vehicle is stopped. That is, the electronic control unit 35
When a signal is input from the wheel speed sensor while the parking brake force is being applied, it is determined that the vehicle has moved, and the control valve 10 is opened. Thereby, the air pressure is supplied from the air chamber 4A of the air tank 4 to the air master 9 through the double check valve 7, and the corresponding hydraulic pressure is supplied to the valve device 13. The valve device 13 is a normally-open valve as described above, and hydraulic pressure is supplied to the right and left rear wheel cylinders 18 and 19 through the control valve unit 15 to stop the vehicle. This prevents the vehicle from moving due to insufficient pulling of the parking brake lever during stopping and parking.

When the parking brake lever is depressed again or the brake pedal 6e is depressed and the parking brake lever is returned, the electronic control unit 35 controls the control valve 1 again.
0 is closed, the air pressure applied to the air master 9 is released to the atmosphere, and the braking force applied to the wheel cylinders 18 and 19 is released. In this way, by making the ABS control a hydraulic control and the ASR control a pneumatic pressure control and a hydraulic control, the brake control ASR can be easily handled especially in a medium-sized air-over vehicle equipped with a hydraulic type ABS. In addition, brake control ASR can be supported without mounting a pump motor as a hydraulic pressure generation source by supporting software of an electronic control device as control means in the basic system of ABS. Further, one air master can correspond to the left and right drive wheels, and the number of air masters can be reduced by one. The air master is heavy and expensive. By reducing the weight, the cost and the frame strength can be reduced, and the weight of the vehicle body and the cost can be reduced.

Further, by using the control valve 10 for ASR also as a parking brake auxiliary valve, the number of parts can be reduced, whereby the structure can be simplified and the cost can be reduced.

[0025]

According to the present invention, a large-capacity pump motor or the like as a hydraulic pressure generating source is not required by performing ASR control for preventing a slip of a driving wheel by air pressure and hydraulic pressure, and a braking control device is provided. Cost is reduced. In addition, a large braking force can be instantaneously applied by the air pressure, thereby facilitating the prevention of slip (ASR) of the drive wheels.

According to the second aspect of the present invention, the number of parts is reduced by using the on-off valve for ASR control also as the parking brake auxiliary valve, so that the structure of the brake control device is simplified and the cost is reduced. Can be

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a vehicle braking control device according to the present invention.

[Explanation of symbols]

 2 Compressor 4 Air tank (air pressure source) 6 Brake valve 8, 9 Air master (power booster) 10 Control valve (open / close valve) 13 Valve device 16-19 Wheel cylinder 35 Electronic control device (control means)

Claims (2)

[Claims] An input side is connected to an air pressure source, a brake valve for supplying air pressure according to an operation amount of a brake pedal to an outlet side, and a brake valve connected to an outlet side of the brake valve to convert air pressure to hydraulic pressure. A booster for transmitting to the wheel cylinder, and a valve device disposed between the booster and the wheel cylinder to control a hydraulic pressure on the wheel cylinder side; and a bypass for the brake valve from the air pressure source. Is arranged in the air passage communicating with the booster on the drive wheel side,
An on-off valve for switching the air passage between open and closed; a vehicle state detecting means for detecting a state of the vehicle; and a control means for driving and controlling the valve device and the on-off valve in accordance with information from the vehicle state detecting means. When the vehicle state detecting means detects slippage of the drive wheel, the on-off valve is opened, and the oil pressure on the wheel cylinder side is controlled by the valve device according to the slip state. A braking control device for a vehicle, comprising: 2. The on-off valve according to claim 1, wherein the on-off valve is a parking brake auxiliary valve that is opened when the movement of the vehicle is detected while the parking brake force is being applied while the vehicle is stopped. The vehicle braking control device according to claim 1.