JPH05155332A - Electric control braking system for connected vehicles - Google Patents

Abstract

(57) [Summary] [Purpose] To reduce the imbalance in braking time lag between the tractor side and trailer side of a connected vehicle. [Composition] A relay valve 17 and a trailer control relay valve 19 of a tractor, which are operated by either signal pressure or electric signal and whose electric signal has priority over signal pressure, are used. Pressure sensor 33 that detects a current and outputs a corresponding electric signal
And the wheel speed sensors 35 and 37 for detecting the wheel speeds of the tractor and the trailer and the signals of the pressure sensor 33 to output corresponding control signals to operate the relay valve 17 and the trailer control relay valve 19, and In response to the signals from the sensors 35 and 37, the relay valve 17 adjusts the wheel speed of the tractor to the wheel speed of the trailer.
And an electronic control unit 40 for controlling the.

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 air tank 12 for braking the trailer,
The air pressure inside 12 is maintained at a predetermined pressure by a pressure governor (not shown).

When the driver operates the brake pedal 4,
The brake valve 3 supplies a signal pressure (air pressure) corresponding to how much the brake pedal 4 is depressed to the relay valve 10 of the trailer via the front relay valve 5, the rear relay valve 6, and the trailer control relay valve 9 of the tractor. The trailer control relay valve 9
It is arranged at the rear of the tractor and is connected to the relay valve 10 on the tractor side through a coupling hose 29.

These relay valves 5, 6, 9 and 10
When the signal pressure is input, compressed air equal to the input pressure is supplied from the air tanks 1, 2 and 12 through the relay valves 5, 6, 9 and 10, respectively, to the front brake chambers 7 and 7'of the tractor and the rear brake chambers. 8, 8 '
And to the brake chambers 11 and 11 'of the trailer to generate braking forces on the front wheels 14, 14', the rear wheels 15, 15 'of the tractor and the rear wheels 16, 16' of the trailer, respectively.

When the driver loosens the brake pedal 4, the air between the brake valve 3 and the relay valves 5, 6, 9 and 10 is exhausted from the brake valve 3 and the braking force is lost, so that the front and rear wheels of the tractor are removed. 14, 14 ', 15, 1
The brakes of 5'and the rear wheels 16 and 16 'of the trailer are released.

[0007]

However, in the above conventional air brake system, since the signal system supplied from the brake valve 3 to the relay valves 5, 6, 9 and 10 is air (signal pressure), the pipe line is not provided. The longer the, the longer the time lag. That is, the trailer control relay valves 9 and 10 have a large time lag because the signal pressure is supplied from the brake valve 3 on the tractor side through a long pipe, and the front wheels 14 and 14 'of the tractor and the rear wheels 16 and 16' of the trailer are large. The imbalance between the shafts becomes large, and the trailer rear wheel 16, the trailer rear wheel 16,
The brake of 16 'is delayed, and the tractor side is pushed up from the trailer side every time the brake is applied, and the feeling during braking is poor.

Further, the tractor and the trailer are not determined in a one-to-one relationship, and their connection modes are various, and it is not known which tractor is connected to which trailer. Moreover, anti-skid brake system (ABS) on the tractor side (controls are performed to keep the slip ratio between the tire and the road surface at an optimum value by applying or releasing brake pressure so that the wheels do not lock during sudden braking. ,
Even if a brake system for stably and quickly stopping the vehicle is provided, if the trailer side is not provided, the above-mentioned feeling of thrusting up during braking becomes extra strong.

The present invention has been made in view of the above points, and detects the effectiveness of the brakes of the tractor and the trailer to adjust the brake on the tractor side to the trailer side, and also sets the trailer control relay valve to an electric signal. It is an object of the present invention to provide an electric control brake system for a connected vehicle in which the unbalance of the braking time lag between the tractors is improved by the control by the above and the feeling is improved.

[0010]

To achieve the above object, according to the present invention, a signal pressure is applied to a relay valve and a trailer control relay valve of a tractor in accordance with the depression amount of a brake pedal to operate the relay valve and the trailer control relay valve. In the air brake system that operates the trailer relay valve by the trailer control relay valve, the tractor relay valve and the trailer control relay valve operate with either the signal pressure or the electric signal and the electric signal takes precedence over the signal pressure. Using a relay valve, a pressure sensor that detects the signal pressure supplied to the relay valve of the tractor and outputs a corresponding electric signal, a wheel speed sensor that detects each wheel speed of the tractor and the trailer, and the pressure. Relay of the tractor by taking in the sensor signal and outputting the corresponding control signal And a trailer control relay valve are operated, and an electronic control unit for controlling the relay valve of the tractor to receive the signal of the wheel speed sensor and adjust the wheel speed of the tractor to the wheel speed of the trailer is provided. It is a thing.

[0011]

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 takes in a signal from the pressure sensor and outputs a corresponding control signal to control the tractor relay valve and the trailer control relay valve. The brake chamber of the tractor is actuated by the air pressure supplied via the relay valve to apply a braking force to the wheels of the tractor. The trailer control relay valve drives the relay valve of the trailer to apply the air pressure of the air tank of the trailer to the brake chamber of the trailer, and apply the braking force to the wheels of the trailer. The trailer control relay valve operates at substantially the same time as the tractor relay valve because it is controlled by an electrical signal, thus compensating for the imbalance of the braking time lag between the tractor and the trailer.

Further, the electronic control unit detects the wheel speeds of the tractor wheel and the trailer wheel during braking, delays the operation of the relay valve on the tractor side in accordance with the speed difference, and slightly increases the brake operation time lag. That is, the braking effect is delayed, and the wheel speed on the tractor side is adjusted to the wheel speed on the trailer side. This eliminates the feeling of thrusting up from the trailer side during braking. Further, when the electric system fails, the tractor side relay valve and the trailer control relay valve are directly operated by the signal pressure from the brake valve to form a complete air system brake system.

[0013]

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 17 and the rear relay valve 18 via 23. Further, these air tanks 1 and 2 are connected to the relay valves 17 and 18 via pipe lines 24 and 25, respectively.

The relay valve 17 is provided with the front brake chambers 7, 7'of the left and right front wheels 14, 14 'of the tractor via the pipe line 26, and the relay valve 18 is provided with the pipe line 27.
The rear brake chambers 8, 8'of the left and right rear wheels 15, 15 'of the tractor are connected via the. The relay valve 17 is located near the front brake chambers 7 and 7 ', and the relay valve 18 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.

Trailer control relay valve 19
Is connected to a pipeline 28 that is branched and connected to the pipeline 23 of the relay valve 18 of the tractor. The trailer control relay valve 19 is connected to the trailer relay valve 10 via a coupling hose 29. There is. Further, an air tank 12 of the trailer is connected to the relay valve 10 via a pipe line 30, and rear brake chambers 11 and 11 ′ of the trailer are connected to the relay valve 10 via a pipe line 31. The relay valve 10 is arranged near the brake chambers 11 and 11 'so that the delay of air transmission to these brake chambers 11 and 11' and the delay of exhaustion are reduced. The trailer control relay valve 19 is arranged in the rear part of the tractor, and the relay valve 10 and the air tank 12 are arranged in the trailer.

Pressure sensors 33 and 34 are connected to the pipelines 22 and 23 immediately downstream of the brake valve 3,
The pressure (air pressure) in the pipe lines 22 and 23 is detected and a corresponding electric signal is output. 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 33 and 34 to detect the operation of the brake valve 3 simultaneously and instantaneously. These pressure sensors 33 and 34 are electronic control units (EC
U) 40.

The front and rear wheels 14, 14 ', 15, on the tractor side,
The wheel speed sensors 35, 35 ', 36, 36' and 37, 37 'are provided on the trailing wheels 15' and the trailer rear wheels 16, 16 ', respectively.
Are provided, and each wheel speed is detected and a corresponding wheel speed signal (electrical signal) is output. Each of these wheel speed signals is input to the electronic control unit 40. still,
These wheel speed sensors 35 to 37 'are used for the anti-skid brake system (A
If equipped with BS), signals from each wheel speed sensor of the system may be used.

The electronic control unit 40 takes in electric signals from the pressure sensors 33 and 34 and outputs relay valve control signals to control the relay valves 17, 18 and 19 and the relay valves 17 to 19, respectively.
Further, the electronic control unit 40 determines the effectiveness of the brake with respect to the change in the wheel speed based on the signals from the wheel speed sensors 35 to 37 ', and the rear wheels 16 and 1 of the trailer.
6 ', front wheels 14, 14' and rear wheels 1 of the tractor
Relay valves 17 and 18 are used to slow down the braking on the tractor side so that 5 and 15 'braking is applied.
To control.

Each relay valve 17, 18, 1 of the tractor
9 is operable by either a signal pressure (air pressure) from the brake valve 3 or an electric signal (control signal) input from the electronic control unit 40,
In normal times, the electric signal is prioritized as an electric control brake (EBS), and the signal pressure (air signal system) from the brake valve 3 is shut off, and when the electric system fails, complete air that operates by the signal pressure from the brake valve 3 is activated. It is regarded as a system brake. That is, the basic brake body of the trailer and tractor is an air brake.

By using electric and pneumatic type relay valves 17, 18 and trailer control relay valve 19 and controlling them by an electric signal during normal operation, the time lag during braking can be shortened. Furthermore,
A conventional pneumatic (non-electrical) relay valve (FIG. 2) was used for the length of the piping path from the trailer control relay valve 19 arranged at the rear part of the tractor to the relay valve 10 on the trailer side. Compared with the case, it is about half or less, and the time lag at the time of braking on the trailer side can be shortened by the length of the shortened pipeline.

The electronic control unit 40 is the antiskid-brake-system (ABS) described above.
The electronic control device may be used, which makes it possible to increase the utilization efficiency of the electronic control device as in the case of the wheel speed sensors 35 to 37 'described above. The operation will be described below.

When the driver operates the brake pedal 4,
The brake valve 3 operates according to the depression amount, and the signal pressure corresponding to the depression / promotion is supplied from the air tanks 1 and 2 to the pipelines 22 and 23 through the brake valve, and the signal pressure of the pipelines 22 and 23 depends on the depression amount. The pressure rises. The pressure in these pipelines 22 and 23 rises in a shorter time as it approaches the brake valve 3, and therefore the pressure sensors 33 and 34
Immediately detects the pressure increase in the lines 22, 23 and applies a corresponding electrical signal to the electronic control unit 40.

The electronic control unit 40 outputs a control signal according to the signals from the pressure sensors 33 and 34 and applies it to the relay valves 17-19. Relay valve 17,
18 operates in response to a control signal to supply the compressed air from the air tanks 1 and 2 to the brake chambers 7, 7 ', 8 and 8'. Further, the relay valve 19 applies the air pressure of the air tank 2 to the relay valve 10 on the trailer side to operate it.
The relay valve 10 supplies the compressed air in the air tank 12 to the brake chambers 11 and 11 ′. The brake chambers 7, 7'and 8, 8'on the tractor side have front wheels 14, 14 'and rear wheels 15, 15' depending on the input air pressure.
To the brake chamber 11 on the trailer side,
11 'applies braking force to the rear wheels 16 and 16' of the trailer. This greatly reduces the time lag during braking on the trailer side.

At the same time, the electronic control unit 40
Wheel speed sensors 35-37 'on the tractor side and the trailer side
The signal from is taken in, the speed change of each wheel is detected, and the effectiveness of the brake is judged. Rear wheel 16 on the trailer side,
16 'is the tractor-side wheels 14, 14' and 15, 1
The effect is slower due to the time lag than 5 ', and therefore the wheel speed is correspondingly faster. Electronic control unit 40
Detects the speed difference between the wheels based on the signals from the wheel speed sensors 35 to 37 ', and according to the speed difference, the relay valve 1
7 and 18 are delayed to delay the braking effect on the tractor side, that is, the brake operation time lag on the tractor side is slightly increased to match the wheel speed on the tractor side to the rear wheel speed on the trailer side, and the time lag between the tractor and the trailer is adjusted. To correct.

As a result, the time lag between the tractor side and the trailer side is reduced, and in particular, the front wheels 14 and 1 of the tractor are reduced.
The imbalance of the time lag during braking between the 4'and the rear wheels 16 and 16 'of the trailer is significantly 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 17, 18 and 19 of the tractor and the relay valve 10 of the trailer is exhausted from the brake valve 3 and the braking force is lost. 14, 14 ',
The brakes on 15, 15 'and the rear wheels 16, 16' of the trailer are released.

In the case where the electronic control unit 40 fails to input a control signal to each of the relay valves 17 to 19 due to some trouble in the electric system,
These relay valves 17 to 19 are operated by the signal pressure directly supplied from the brake valve 3 through the pipe lines 22, 23 and 28 instead of the control signal. That is, when the driver operates the brake pedal 4, a signal pressure corresponding to the amount of depression and depression of the brake pedal 4 is applied from the brake valve 3 to the relay valves 17 to 19.
And the relay valves 17 to 19 are operated. As a result, the brake system of the tractor and trailer operates as a complete air system brake when the electric system fails.

[0027]

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. Particularly, when the anti-skid brake system is installed on the tractor side and the anti-skid brake system is not installed on the trailer side, the above-mentioned feeling of thrust is effectively eliminated. Also, the brake system on the trailer side is
When the electric system fails, there is an excellent effect that it can be operated as a complete air system brake.

[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, 12 Air tank 3 Brake valve 4 Brake pedal 7, 7 ', 8, 8', 11, 11 'Brake chamber 10 Trailer side relay valve 17, 18 Relay valve 19 Trailer control relay valve 20-31 Pipeline 33, 34 pressure sensor 35, 35 'to 37, 37' wheel speed sensor 40 electronic control unit

Claims (1)

[Claims] 1. An air brake system in which a signal pressure is applied to a relay valve of a tractor and a trailer control relay valve according to a depression amount of a brake pedal to operate the relay valve, and the trailer control relay valve operates a relay valve of the trailer. For the relay valve of the tractor and the relay control relay valve, a relay valve that operates with either the signal pressure or the electrical signal and the electrical signal has priority over the signal pressure is used, and the signal pressure supplied to the relay valve of the tractor is used. A pressure sensor that detects a pressure, outputs a corresponding electric signal, a wheel speed sensor that detects each wheel speed of the tractor and the trailer, and outputs a corresponding control signal by taking in the signal of the pressure sensor to output a relay of the tractor. Actuating the valve and trailer control relay valve And an electronic control unit for controlling a relay valve of the tractor so as to adjust the wheel speed of the tractor to the wheel speed of the trailer in response to a signal from the wheel speed sensor. .