JPH05139284A - Electrically controlled brake system for connected vehicle - Google Patents

Abstract

PURPOSE:To reduce the unbalance of braking time lag between the tractor side and trailer side of a connected vehicle. CONSTITUTION:An air brake system is formed in such a way as to apply signal pressure to relay valves 5, 6 and 12 from the respective air tanks 1, 2 and 11 of a tractor and a trailer by a brake valve 3 so as to apply air pressure to the brake chambers 7, 8 and 10 of the tractor and trailer through the respective relay valves. In such an air brake system, the relay valve 12 is to be the one operated by either signal pressure or an electric signal, with priority given to the electric signal over the signal pressure, and there are also provided pressure sensors 13, 14 for detecting the signal pressure supplied to the relay valves 5, 6 of the tractor, and an electronic control unit 15 for taking in the signals of the pressure sensors 13, 14 so as to output a corresponding control signal to operate the relay valve 12.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an electric control brake system for an articulated vehicle.

[0002]

2. Description of the Related Art Vehicle brake systems mainly include hydraulic brakes and air (air) brakes. Hydraulic brake systems have excellent responsiveness, simple structure, and high degree of freedom in design. It has advantages and is used in all passenger cars, etc. except vehicles equipped with air brakes. On the other hand, the air brake system can be controlled only by opening and closing the brake valve, a large braking force can be obtained with a small pedaling force, and since the air is compressible, there is some air leakage from the piping system. However, there is no significant decrease in braking force, and it has the characteristics of withstanding severe operating conditions. Furthermore, work such as disassembling the hydraulic brake, replacing the brake fluid necessary for assembly, and bleeding air is unnecessary. It has good properties and is advantageous as a brake for connected vehicles that connects and disconnects. Therefore, the air brake system
It is used in large trucks, buses, tractors and trailers, and other vehicles.

FIG. 2 shows an example of the construction of an air brake system employed in a conventional vehicle in which a tractor and a trailer are connected. Air compressed by a compressor driven by an engine is used for front and rear brakes of the tractor. The air tanks 1 and 2, which are stored in the air tanks 1 and 2 and the brake air tank 11 of the trailer,
The air pressure inside 11 is maintained at a predetermined pressure by a pressure governor.

When the driver operates the brake pedal 4,
The brake valve 3 supplies a signal pressure (air pressure) according to how much the brake pedal 4 is stepped on or off to the front relay valve 5, the rear relay valve 6 of the tractor and the relay valve 9 of the trailer.
Supply to. When the signal pressure is input, these relay valves 5, 6 and 9 supply compressed air equal to the input pressure from the air tanks 1, 2 and 11 respectively.
It is supplied to the front brake chambers 7 and 7'of the tractor, the rear brake chambers 8 and 8'and the brake chambers 10 and 10 'of the trailer through 6 and 9 to generate braking force on the front and rear wheels of the tractor and the rear wheels of the trailer.

When the driver loosens the brake pedal 4, the air between the brake valve 3 and the relay valves 5, 6 and 9 is exhausted from the brake valve 3 and the braking force is lost. The wheel brakes are released.

[0006]

However, in the above-mentioned conventional air brake system, since the signal system supplied from the brake valve 3 to each relay valve 5, 6, 9 is air (signal pressure), the pipe line is long. The longer the time lag, the greater the imbalance between the front wheel of the tractor and the rear wheel of the trailer. In particular, the relay valve 9 of the trailer has a large time lag because the signal pressure is supplied from the brake valve 3 on the tractor side through the coupling hose, which delays the braking of the rear wheels of the trailer relative to the front wheels of the tractor. When the brakes are applied, the tractor is pushed up from the trailer side each time the brakes are applied, and the feeling during braking is poor. There is also a problem that the stopping distance becomes long.

The present invention has been made in view of the above-mentioned points, and controls the relay valve of the trailer by an electric signal to eliminate the transmission of a response, to improve the imbalance of the braking time lag with the tractor and to improve the feeling during braking. An object of the present invention is to provide an electric control brake system for an articulated vehicle, which is designed to improve the ring.

[0008]

In order to achieve the above object, according to the present invention, each tractor and trailer is separated from each air tank of the tractor and the trailer through a brake valve that operates according to the amount of depression of the brake pedal. The relay valve of the trailer of the air brake system is operated by applying a signal pressure to each relay valve and applying air pressure from each air tank to each brake chamber of the tractor and the trailer via each relay valve. Or a pressure sensor that operates with any of the electric signals, and uses a relay valve in which the electric signal has priority over the signal pressure, and that outputs a corresponding electric signal by detecting the signal pressure supplied to the relay valve of the tractor, The relay valve of the trailer is produced by taking in the signal of the pressure sensor and outputting the corresponding control signal. It is obtained by an electronic control unit to the structure provided with.

[0009]

The pressure sensor detects the signal pressure supplied to the relay valve of the tractor in response to the operation of the brake valve and outputs a corresponding electric signal. The electronic control unit receives the signal from the pressure sensor and outputs a corresponding control signal to control the relay valve of the trailer. The air pressure in the air tank of the trailer is supplied to the brake chamber of the trailer through the relay valve, and applies the braking force to the rear wheels. Since the relay valve of the trailer operates at substantially the same time as the relay valve of the tractor because it is controlled by an electric signal, the braking time lag between the tractor and the trailer is greatly shortened, and the imbalance of the braking time lag is improved. If the electrical system fails,
The relay valve of the trailer is directly operated by the signal pressure from the brake valve to form a complete air system brake system.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the accompanying drawings. The same members as those in FIG. 2 are designated by the same reference numerals. FIG. 1 shows a brake system of a vehicle to which a tractor and a trailer are applied, to which the present invention is applied. An air tank 1 for a front brake and an air tank 2 for a rear brake of the tractor include a brake valve 3 via pipe lines 20 and 21, respectively. Connected from the brake valve 3 to the pipe line 22,
It is connected to the front relay valve 5 and the rear relay valve 6 via 23. Also, these air tanks 1,
2 is connected to the front relay valve 5 and the rear relay valve 6 via piping lines 24 and 25, respectively.

The front relay valve 5 is connected to the front brake chambers 7 and 7'of the left and right front wheels of the tractor via a pipe line 26, and the rear relay valve 6 is connected via a pipe line 27 to the left and right rear sides of the tractor. The wheel rear brake chambers 8, 8'are connected. The front relay valve 5 is located near the front brake chambers 7 and 7 ', and the rear relay valve 6 is located near the rear brake chambers 8 and 7.
8'is located near each brake chamber 7,
The delay of air transmission to 7 ', 8, 8'and the exhaust delay are reduced.

A pipe passage 28 is branched and connected to the pipe passage 23 of the relay valve 6 of the tractor, and the relay valve 12 of the trailer is connected to the pipe passage 28 via a coupling hose 29. Also, this relay valve 1
2 to the air tank 11 of the trailer via the pipeline 30
However, the rear brake chambers 10 and 10 ′ of the trailer are connected to each other via a pipeline 31. Relay valve 1
2 is arranged near the brake chambers 10 and 10 'so that the delay of air transmission to these brake chambers 10 and 10' and the exhaust delay thereof are reduced. The air tank 11 and the relay valve 12 are arranged on the trailer.

The relay valve 12 is operated by either a signal pressure (air pressure) input from the brake valve 3 as a control signal or an electric signal (control signal) input from an electronic control unit 15 described later. It is possible. Pressure sensors 13 and 14 are connected to the pipelines 22 and 23 immediately downstream of the brake valve 3 to detect the pressure (air pressure) in the pipelines 22 and 23 and output a corresponding electric signal. The pressure immediately downstream of the brake valve 3 in the pipe lines 22 and 23 rises immediately when the brake valve 3 is activated. Therefore, this allows the pressure sensors 13 and 14 to detect the operation of the brake valve 3 simultaneously and instantaneously. These pressure sensors 13 and 14 are connected to an electronic control unit (ECU) 15. The electronic control unit 15 takes in electric signals from the pressure sensors 13 and 14 and outputs a corresponding relay valve control signal to apply it to the trailer 12 of the trailer.

The relay valves 5 and 6 of the tractor are full air system brakes which operate by the signal pressure from the brake valve 3. Also, the trailer relay valve 12
Can be operated by either the signal pressure (air pressure) from the brake valve 3 or the electric signal (control signal) input from the electronic control unit 15 as described above. The signal pressure (air signal system) from the brake valve 3 is cut off by an electric control brake (EBS) that operates, and a complete air system brake that operates by the signal pressure from the brake valve 3 when the electric system fails. That is, the basic brake body of the trailer is an air brake, like the tractor.

The electronic control unit 15 is an anti-skid-brake system (ABS) that is being widely adopted in the current vehicles, that is, by applying or releasing brake hydraulic pressure so that the wheels do not lock during sudden braking. It is also possible to use an electronic control unit of a brake system that controls the slip ratio between the tires and the road surface at an optimum value to stop the vehicle in a stable and fast manner. The efficiency can be increased.

The operation will be described below. When the driver operates the brake pedal 4, the brake valve 3 is activated according to the amount of depression, and a signal pressure corresponding to the amount of depression and depression is transmitted from the air tanks 1 and 2 through the brake valve to the front and rear relay valves 5 and 6 of the tractor. And the relay valves 5 and 6 are operated. Relay valve 5,6
When the signal pressure is input, the compressed air equal to the input pressure is supplied from the air tanks 1 and 2 to the front brake chambers 7 and 7'and the rear brake chambers 8 and 8'through the relay valves 5 and 6, and the front wheels Also, a braking force is generated on the rear wheels (both not shown). As a result, braking force is applied to the front and rear wheels of the tractor.

When the brake pedal 4 is depressed, the pressure in the pipe lines 22 and 23 rises according to the amount of depression. The pressure in these pipe lines 22 and 23 rises in a shorter time as it gets closer to the brake valve 3, and the pressure sensor 13 and
14 instantaneously detects the pressure increase in the pipe lines 22 and 23, outputs a corresponding electric signal, and applies it to the electronic control unit 15.

The electronic control unit 15 outputs a control signal in response to the signals from the pressure sensors 13 and 14 to add the relay valve 12 of the trailer. Relay valve 12
Operates in response to the control signal to supply the compressed air in the air tank 11 to the brake chambers 10 and 10 '. Each of the brake chambers 10 and 10 'applies a braking force to the rear wheel (not shown) of the trailer according to the input air pressure.

The electronic control unit 15 outputs a control signal substantially at the same time as the operation of the relay valves 5 and 6 of the tractor to operate the relay valve 12 of the trailer. Therefore, the relay valve 12 of the trailer is the brake valve 3
Even if the pipe lines 28 and 29 from the valve are long, they operate almost simultaneously with the relay valves 5 and 6 of the tractor. As a result, the front brake chambers 7, 7'and rear brake chambers 8, 8'of the tractor and the brake chambers 10, 1 of the trailer are shown.
0'acts at almost the same time, and there is no time lag between them. As a result, the imbalance of the braking time lag between the front and rear wheels of the tractor and the rear wheels of the trailer is greatly improved, and the feeling of thrusting up from the trailer during braking is eliminated.

When the driver loosens the brake pedal 4, the air between the brake valve 3 and the relay valves 5 and 6 of the tractor and the relay valve 12 of the trailer is exhausted from the brake valve 3 and the braking force is lost. The brakes on the front and rear wheels and the rear wheels of the trailer are released. In addition, when the control signal is not input from the electronic control unit 15 to the relay valve 12 due to some failure of the electric system, the relay valve 12 concerned
Instead of the control signal from the Bregi valve 3 to the pipe 28
And the signal pressure supplied directly through the coupling hose 29. That is, the driver is the brake pedal 4
When is operated, a signal pressure according to the amount of depression and depression is supplied from the brake valve 3 to the relay valve 12, and the relay valve 12 is operated. As a result, the brake system of the trailer operates as a complete air system brake when the electric system fails.

[0021]

As described above, according to the present invention, the braking time lag between the front and rear wheels on the tractor side and the rear wheels on the trailer side of an articulated vehicle is shortened, and the imbalance of the braking time lag between the axes is significantly reduced. It is possible to improve, and the feeling of pushing up due to the delay of the trailer side braking effect is eliminated,
The feeling when braking is improved. Further, the brake system on the trailer side has an excellent effect that it can be operated as a complete air system brake when the electric system fails.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an electric control brake system for a combined vehicle according to the present invention.

FIG. 2 is a block diagram showing an example of a conventional air brake system for a coupled vehicle.

[Explanation of symbols]

 1, 2 Tractor side air tank 3 Brake valve 4 Brake pedal 5, 6 Tractor side relay valve 7, 7 ', 8, 8' Tractor side brake chamber 10, 10 'Trailer side brake chamber 11 Trailer side air tank 12 Trailer side relay valve 13 , 14 Pressure sensor 15 Electronic control unit 20-31 Pipe line

Claims (1)

[Claims] 1. A signal pressure is applied to each relay valve of the tractor and trailer from each air tank of the tractor and trailer via a brake valve that operates according to the amount of depression of the brake pedal, and each of the air tanks is actuated. Applying air pressure to each brake chamber of the tractor and trailer via each relay valve, the relay valve of the trailer of the air brake system operates with either the signal pressure or the electrical signal, and the electrical signal takes precedence over the signal pressure. Pressure sensor for detecting a signal pressure supplied to the relay valve of the tractor and outputting a corresponding electric signal, and a trailer for outputting a corresponding control signal by taking in the signal of the pressure sensor. And an electronic control unit for operating the relay valve of Electric control braking system for connected vehicles.