Drive-by-wire air brake system of extra-heavy special off-road vehicle

Abstract

The invention discloses an extra-heavy special off-road vehicle drive-by-wire air brake system which comprises an air compressor, a condenser, an air dryer, a four-loop protection valve, an automobile electric control unit, a brake valve, an air cylinder, a brake air chamber and a hand brake valve. Air inlets of the brake valve and the proportional relay valves are connected with the air storage cylinder, the brake valve and a front axle and a rear axle of a vehicle are respectively provided with a group of proportional relay valves, air pressure sensors are integrated at air outlets of the proportional relay valves, and the brake valve, the proportional relay valves and the air pressure sensors are all electrically connected with the vehicle electric control unit. A differential relay valve is arranged on a connecting air path of the hand brake valve and the brake air chamber used for parking, air inlets of the hand brake valve and the differential relay valve are both connected with an air storage cylinder, a low-air-pressure alarm switch is integrated on an air outlet of the differential relay valve, and the hand brake valve is provided with an electromagnetic valve in parallel.

Description

Technical Field

[0001] The invention relates to the technical field of automobile braking, in particular to a wire-controlled pneumatic braking system for an ultra-heavy special off-road vehicle. Background Art

[0002] The braking system is an important part of the vehicle and is related to the safety of vehicle operation. The air brake system of ordinary heavy-duty vehicles is generally composed of an air compressor, a condenser, an air handling unit, a brake valve, a relay valve, a differential relay valve, an air reservoir, etc. The distance from the brake valve of an ordinary heavy-duty vehicle to the farthest brake air chamber is short, and the braking reaction time has limited effect on the braking effect. However, super-heavy special off-road vehicles have a large tonnage, a large number of axles, and a long vehicle. If the braking system is not designed reasonably and the braking reaction time is too long, it will seriously affect the braking effect of the vehicle and further affect driving safety. Super-heavy special off-road vehicles are long, have a large number of axles, and the pipelines of the brake air pressure circuit are very long, which prolongs the braking reaction time, ultimately increasing the braking distance of the vehicle and increasing the risk of driving safety.

[0003] At the same time, vehicles currently equipped with pneumatic brake systems need to be equipped with an EBS system to achieve unmanned driving functions. The system is provided as a complete set by the supplier, and the development and debugging costs are high. The development cost of the chassis or small batch chassis is high, and the development cost cannot be effectively reduced. Summary of the invention

[0004] In view of the above technical problems, the present invention proposes a wire-controlled pneumatic brake system for an ultra-heavy special off-road vehicle. The wire-controlled pneumatic brake system solves the problem of long braking reaction time caused by the length of the vehicle and the large number of axles in the prior art, and also solves the problem of achieving conventional braking during manned driving and service braking functions during unmanned automatic driving at low cost. It adopts a redundant design to increase the reliability of vehicle braking.

[0005] A wire-controlled pneumatic brake system for an ultra-heavy special off-road vehicle comprises an air compressor, a condenser, an air dryer, a four-circuit protection valve, an automobile electronic control unit, a brake valve, an air reservoir, a brake air chamber, and a hand brake valve. A proportional relay valve is provided on the connecting air path between the brake valve and the brake air chamber. The air inlets of the brake valve and the proportional relay valve are both connected to the air reservoir. The brake valve and the front and rear axles of the vehicle each have a group of air outlets of the proportional relay valve integrated with an air pressure sensor. The brake valve, the proportional relay valve and the air pressure sensor are all electrically connected to the automobile electronic control unit. A differential relay valve is provided on the connecting air path between the hand brake valve and the brake air chamber for parking. The air inlets of the hand brake valve and the differential relay valve are both connected to the air reservoir. A low air pressure alarm switch is integrated at the air outlet of the differential relay valve. A solenoid valve is installed in parallel with the hand brake valve.

[0006] As a preferred embodiment of the above technical solution, the brake valve is provided with two air control circuits, and the brake air chambers and proportional relay valve controls are correspondingly provided with five groups, the first two groups of brake air chambers are used for the front axle of the vehicle, and the corresponding two groups of proportional relay valves are controlled by one air control circuit, and the last two or three groups of brake air chambers are used for the rear axle of the vehicle, and the corresponding three groups of proportional relay valves are controlled by another air control circuit.

[0007] As a preferred embodiment of the above technical solution, the air cylinders are provided with four groups, wherein two groups of the air cylinders are respectively connected to the air control circuit of the brake valve and the proportional relay valve of the front and rear axles of the vehicle, and are used to adjust the brake air chamber pressure of the front and rear axles of the vehicle, respectively, the third group is used for the parking circuit, and the fourth group is used for auxiliary braking.

[0008] As a preferred embodiment of the above technical solution, each of the air storage cylinders is equipped with a drain valve.

[0009] As a preferred embodiment of the above technical solution, the brake valve adopts a double-chamber tandem brake valve.

[0010] The beneficial effects of the present invention are:

[0011] 1. The invention realizes a wire-controlled pneumatic brake system for ultra-heavy special off-road vehicles with five axles or more. The solution can realize the manned and unmanned driving braking functions of the chassis.

[0012] 2. After the service brake wire control system fails, the driver can still achieve service braking of the wheel brakes by operating the emergency brake valve.

[0013] 3. When someone is driving, the air circuit control of the traditional mechanical chassis is still retained, the changes to the traditional mechanical chassis are small, and the air circuit system is almost unchanged.

[0014] 4. This invention saves costs compared to the existing EBS system and can realize the unmanned driving function of the chassis.

[0015] 5. An air pressure sensor is added to the outlet of the proportional relay valve to feedback the air pressure output of the proportional relay valve to the automotive electronic control unit. The automotive electronic control unit can make fine adjustments based on the feedback results to improve the accuracy of the air pressure output of the proportional relay valve according to the braking force requirements of the vehicle.

[0016] 6. The redundant design of air control and wire control of the service brake system of the invention increases reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is the schematic diagram of the wire-controlled air pressure brake system.

[0018] The accompanying drawings are marked as follows: 1-air compressor, 2-condenser, 3-air dryer, 4-four-circuit protection valve, 5-automotive electronic control unit, 6-brake valve, 7-hand brake valve, 8-differential relay valve, 9-low pressure alarm switch, 10-solenoid valve, 11-brake air chamber one, 12-brake air chamber two, 13-brake air chamber three, 14-brake air chamber four, 15-brake air chamber five, 16-proportional relay valve one, 17-proportional relay valve two, 18-proportional relay valve three, 19-proportional relay valve four, 20-proportional relay valve five, 21-air pressure sensor one, 22-air pressure sensor two, 23-air pressure sensor three, 24-air pressure sensor four, 25-air cylinder one, 26-air cylinder two, 27-air cylinder three, 28-air cylinder four. DETAILED DESCRIPTION

[0019] The technical solution of the present invention is described clearly and completely below in conjunction with the accompanying drawings of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] like Figure 1 A super-heavy special off-road vehicle wire-controlled pneumatic brake system is shown, comprising an air compressor 1, a condenser 2, an air dryer 3, a four-circuit protection valve 4, an automobile electronic control unit 5, a brake valve 6, an air reservoir, a brake air chamber, and a hand brake valve 7. A proportional relay valve is provided on the connecting air path between the brake valve and the brake air chamber, the air inlets of the brake valve and the proportional relay valve are both connected to the air reservoir, the brake valve and the front and rear axles of the vehicle each have a group of air outlets of the proportional relay valve integrated with an air pressure sensor, the brake valve 6, the proportional relay valve and the air pressure sensor are all electrically connected to the automobile electronic control unit 5, a differential relay valve 8 is provided on the connecting air path between the hand brake valve 7 and the brake air chamber for parking, the air inlets of the hand brake valve 7 and the differential relay valve 8 are both connected to the air reservoir, the air outlet of the differential relay valve 8 is integrated with a low air pressure alarm switch 9, and the hand brake valve 7 is installed in parallel with a solenoid valve.

[0021] In this embodiment, the brake valve 6 is provided with two air control circuits, and the brake air chamber 6 and the proportional relay valve control are correspondingly provided with five groups. The first two groups of the brake air chambers are used for the front axle of the vehicle, namely the brake air chamber 1 11 and the brake air chamber 2 12, and the corresponding two groups of proportional relay valves are controlled by one air control circuit, namely the proportional relay valve 1 16 and the proportional relay valve 2 17; the last two groups of the brake air chambers are used for the rear axle of the vehicle, namely the brake air chamber 3 13, the brake air chamber 4 14 and the brake air chamber 5 15, and the corresponding three groups of proportional relay valves are controlled by another air control circuit, namely the proportional relay valve 3 18, the proportional relay valve 4 19 and the proportional relay valve 5 20. Among them, the air pressure sensors provided at the two air outlets of the brake valve 6 are respectively the air pressure sensor 1 21 and the air pressure sensor 2 22, the air outlet of the proportional relay valve 1 16 is provided with the air pressure sensor 3 23, and the air outlet of the proportional relay valve 3 18 is provided with the air pressure sensor 4 214.

[0022] In this embodiment, the air cylinders are provided with four groups, namely, air cylinder one 25, air cylinder two 26, air cylinder three 27, and air cylinder four 28, wherein air cylinder one 25 and air cylinder two 26 are respectively connected to the air control circuit of the brake valve 6 and the proportional relay valve of the front and rear axles of the vehicle, and are respectively used to adjust the brake air chamber pressure of the front and rear axles of the vehicle, air cylinder three 27 is used in the parking circuit, and air cylinder four 28 is used for auxiliary braking.

[0023] In this embodiment, each of the air storage cylinders is equipped with a drain valve.

[0024] In this embodiment, the brake valve 6 is a double-chamber serial brake valve.

[0025] In this embodiment, the brake valve 6 is a double-chamber serial brake valve.

[0026] Specifically, the brake valve 6 includes two air inlets and two air outlets. At the same time, the brake valve 6 is integrated with two displacement sensors, which can output the same voltage signal according to the pedal stroke. When someone is driving, the driver steps on the brake pedal on the brake valve 6, and the brake valve 6 outputs air pressure at the air outlet. The air pressure sensor 1 21 and the air pressure sensor 2 22 can identify the driver's braking intention and the action of stepping on the brake pedal on the brake valve 6. The two air pressure sensors 1 21 and 22 can output the same pedal stroke signal according to the brake pedal stroke on the brake valve 6. At the same time, the automobile electronic control unit 5 outputs two control signals to the proportional relay valve according to the input signal to control its on and off.

[0027] The proportional relay valve can realize both air control and electric control, including an air inlet, an air outlet, an exhaust port, an air control interface, and an electric control interface, wherein the air inlet is connected to the air tank through a pipeline, the air outlet is connected to the brake air chamber through a pipeline, the exhaust port is used for exhaust, the air control interface is connected to one of the air outlets of the brake valve 6, and the electric control interface is connected to the vehicle electronic control unit 5.

[0028] The working principle of this embodiment is as follows.

[0029] When someone is driving: when the parking brake is released, the driver operates the hand brake valve 7 to connect the air inlet and the air outlet of the hand brake valve 7, and the compressed air in the air reservoir three 27 enters the control port 7 of the differential relay valve 8 through the hand brake valve 7, and controls the air inlet and the air outlet of the differential relay valve 8 to be connected. At this time, the compressed air in the air reservoir three 27 enters the spring chambers of the brake air chamber two 12, the brake air chamber two 13, and the brake air chamber two 14 through the differential relay valve 8, and the parking brake is released. When the vehicle needs parking brake, the driver operates the hand brake valve 7 to disconnect the air inlet and outlet of the hand brake valve 7, and at the same time, the air outlet and exhaust port of the hand brake valve 7 are connected, and the compressed air in the control port circuit of the differential relay valve 8 is discharged through the exhaust port of the hand brake valve 7, the air inlet and outlet of the differential relay valve 8 are disconnected, and the compressed air in the spring cavity of the brake air chamber 2 12, the brake air chamber 2 13, and the brake air chamber 2 14 is discharged through the exhaust port of the differential relay valve 8, and the springs in the brake air chamber 2 12, the brake air chamber 2 13, and the brake air chamber 2 14 push the push rod out to perform parking brake.

[0030] When the driver steps on the brake pedal on the brake valve 6, the air inlet and outlet of the brake valve 6 are connected, and the compressed air in the air reservoir 1 25 and the air reservoir 2 26 enters the proportional relay valve through the brake valve 6. During this process, the air pressure sensor 1 21 and the air pressure sensor 2 22 at the air outlet of the brake valve 6 transmit the air pressure signal to the automobile electronic control unit 1. The automobile electronic control unit 1 determines that there is someone driving through the air pressure signal. At this time, the proportional relay valve receives the air circuit control signal to respond. At this time, the proportional relay valve is not controlled by the signal generated by the displacement sensor integrated in the brake valve 6. When there is someone driving, the wire control circuit of the brake valve 6 can be used as a redundancy of the air control circuit. When the air control circuit of the brake valve 6 cannot build up pressure due to a leakage fault, the air pressure sensor 1 21 and the air pressure sensor 2 22 on the brake valve 6 have no signal. The automobile electronic control unit 1 can receive the displacement sensor signal of the brake valve 6 to control the action of the proportional relay valve 5.

[0031] When no one is driving: when the parking brake needs to be released, the solenoid valve 10 receives the signal from the vehicle controller, the air inlet and outlet of the solenoid valve 10 are connected, the compressed air in the air reservoir three 27 enters the differential relay valve 8 through the solenoid valve 10 to control the connection between the air inlet and outlet of the differential relay valve 8, the compressed air in the air reservoir three 27 enters the spring chambers of the brake air chamber two 12, the brake air chamber two 13, and the brake air chamber two 14 through the differential relay valve 8, and the parking brake is released. When the vehicle needs parking brake, after the solenoid valve 10 receives the signal, the air inlet and outlet of the solenoid valve 10 are disconnected, and at the same time, the air outlet and exhaust port of the solenoid valve 10 are connected, and the compressed air in the control port circuit of the differential relay valve 8 is discharged through the exhaust port of the solenoid valve 10, the air inlet and outlet of the differential relay valve 8 are disconnected, and the compressed air in the spring cavity of the brake air chamber 2 12, the brake air chamber 2 13, and the brake air chamber 2 14 is discharged through the exhaust port of the differential relay valve 8, and the springs in the brake air chamber 2 12, the brake air chamber 2 13, and the brake air chamber 2 14 push the push rod out to perform parking brake.

[0032] When the vehicle needs to brake, the vehicle controller sends a braking demand to the automobile electronic control unit 5. The automobile electronic control unit 5 outputs a control signal to the electronic control interface of the proportional relay valve through the signal to control the air pressure output of the proportional relay valve. The compressed air in the air reservoir 1 25 and the air reservoir 2 26 enters the brake air chamber through the proportional relay valve, and the air chamber push rod acts on the wheel brake to brake. The output air pressure of the proportional relay valve forms a certain curve relationship with the braking force of the wheel brake. During the braking process, the air pressure sensor 3 23 and the air pressure sensor 4 24 at the outlet of the proportional relay valve 1 16 and the proportional relay valve 3 collect air pressure signals and feed them back to the automobile electronic control unit 5. When the braking force represented by the air pressure signal does not meet the demand issued by the vehicle controller, the automobile electronic control unit 5 adjusts the output air pressure by adjusting the opening of the proportional relay valve to form a control closed loop.

[0033] In the above description, whether the vehicle is in a parking state or not, when the service brake is executed, the differential relay valve 8 receives the compressed air provided by the outlet of the proportional relay valve 2 17, so that the air inlet and outlet of the differential relay valve 8 are connected, and the parking brake is released. That is, the parking brake does not work during service brake, in order to prevent the air chamber push rod from superimposing the force of the air chamber driving chamber and the parking chamber, which may cause the push rod to deform or the brake to fail.

[0034] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A wire-controlled pneumatic brake system for an ultra-heavy special off-road vehicle, characterized in that: An air compressor, a condenser, an air dryer, a four-circuit protection valve, an automobile electronic control unit, a brake valve, an air reservoir, a brake air chamber, and a hand brake valve. A proportional relay valve is provided on the connecting air path between the brake valve and the brake air chamber. The air inlets of the brake valve and the proportional relay valve are both connected to the air reservoir. The brake valve and the front and rear axles of the vehicle each have a group of air outlets of the proportional relay valve integrated with an air pressure sensor. The brake valve, the proportional relay valve and the air pressure sensor are all electrically connected to the automobile electronic control unit. A differential relay valve is provided on the connecting air path between the hand brake valve and the brake air chamber used for parking. The air inlets of the hand brake valve and the differential relay valve are both connected to the air reservoir. A low air pressure alarm switch is integrated at the air outlet of the differential relay valve. A solenoid valve is installed in parallel with the hand brake valve.

2. The super heavy-duty special off-road vehicle wire-controlled pneumatic brake system according to claim 1, characterized in that: The brake valve is provided with two air control circuits, and the brake air chambers and proportional relay valve controls are correspondingly provided with five groups. The first two groups of brake air chambers are used for the front axle of the vehicle, and the corresponding two groups of proportional relay valves are controlled by one air control circuit. The last two or three groups of brake air chambers are used for the rear axle of the vehicle, and the corresponding three groups of proportional relay valves are controlled by another air control circuit.

3. The super heavy-duty special off-road vehicle wire-controlled pneumatic brake system according to claim 1, characterized in that: The air cylinders are provided with four groups, wherein two groups of the air cylinders are respectively connected to the air control circuits of the brake valves and the proportional relay valves of the front and rear axles of the vehicle, and are respectively used to adjust the brake chamber pressures of the front and rear axles of the vehicle, the third group is used for the parking circuit, and the fourth group is used for auxiliary braking.

4. The super heavy-duty special off-road vehicle wire-controlled pneumatic brake system according to claim 3, characterized in that: Each of the air storage cylinders is equipped with a drain valve.

5. The super heavy-duty special off-road vehicle wire-controlled pneumatic brake system according to claim 1, characterized in that: The brake valve adopts a double-chamber serial brake valve.

Images