A lift truck rear axle brake control system and method

Abstract

The application belongs to the technical field of vehicle braking, and specifically provides a rear axle braking control system and method for a lift vehicle, which comprises an EBS axle module, a two-position three-way electromagnetic valve, a double-pass low selection valve and an EBS electric control unit, the EBS axle module is directly connected to the driving axle braking running cavity, the two-position three-way electromagnetic valve is connected to the left and right two-way braking running cavities of the lift axle through two double-pass low selection valves, and the EBS electric control unit is connected to the EBS axle module and the two-position three-way electromagnetic valve. By adding two double-pass low selection valves and a two-position three-way electromagnetic valve to replace the six-channel EBS control system, the problem of the lift axle dragging can be solved when the driving wheel slips and activates the ASR function, the tire wear is reduced, and the braking performance is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicle braking, in particular to a rear axle brake control system and method for a lift vehicle. BACKGROUND

[0002] With the rapid development of infrastructure and economy in recent years, the role of the lift axle in transport vehicles is increasingly widely accepted and applied. The application of the lift axle is mostly to replace the drive axle with the non-drive axle. When the vehicle is heavily loaded, the lift axle is lowered, the load bearing capacity of the vehicle is enhanced. When the vehicle is unloaded or lightly loaded, the lift axle can be lifted to reduce tire wear and fuel consumption.

[0003] Currently, the brake control system for the lift axle is mostly a six-channel ABS or six-channel EBS control system, which has a large number of components. When the lift axle is on the ground, it is in a follow-up state. Without ABS solenoid control of the lift axle under the four-channel control system, the lift axle is in a locked and dragged state under emergency braking, which causes serious tire wear and reduces the performance and efficiency of the brake system.

[0004] Therefore, it is necessary to provide a four-channel EBS brake control system and method that can solve the problem of drag of the lift axle during the braking process of the lift vehicle. SUMMARY

[0005] To solve the above problems, the present application provides a four-channel EBS brake control system and method that can solve the problem of drag of the lift axle during the braking process of the lift vehicle.

[0006] In a first aspect, the present application provides a rear axle brake control gas circuit device for a lift vehicle, which comprises an EBS axle module, a two-position three-way electromagnetic valve, a double-pass low selection valve, a drive axle right side brake chamber service cavity, a drive axle left side brake chamber service cavity, a lift axle right side brake chamber service cavity, and a lift axle left side brake chamber service cavity.

[0007] The double-pass low selection valve comprises a first double-pass low selection valve and a second double-pass low selection valve. Each double-pass low selection valve comprises a first air inlet, a second air inlet, and an air outlet.

[0008] The EBS bridge module is provided with an air inlet, the air inlet of the EBS bridge module is communicated with a service brake air source port, the EBS bridge module is provided with a first air outlet, a second air outlet, a third air outlet and a fourth air outlet, the first air outlet of the EBS bridge module is connected with a service cavity of a right side brake air chamber of a drive axle, the third air outlet of the EBS bridge module is connected with a service cavity of a left side brake air chamber of the drive axle, the second air outlet of the EBS bridge module is communicated with a first air inlet of a first double-pass low selection valve, an air outlet of the first double-pass low selection valve is connected with a service cavity of a right side brake air chamber of a lifting axle, the fourth air outlet of the EBS bridge module is communicated with a first air inlet of a second double-pass low selection valve, an air outlet of the second double-pass low selection valve is connected with a service cavity of a left side brake air chamber of the lifting axle; the EBS bridge module is provided with a control port, and the control port of the EBS bridge module is communicated with a service brake control port through an air pipe.

[0009] The two-position three-way electromagnetic valve is provided with an air inlet and an air outlet; the air inlet of the two-position three-way electromagnetic valve is connected with the service brake air source port; the air outlet of the two-position three-way electromagnetic valve is communicated with a second air inlet of the first double-pass low selection valve and a second air inlet of the second double-pass low selection valve respectively.

[0010] The four-channel EBS control gas path device provided by the application adds two double-pass low selection valves and a normally open two-position three-way electromagnetic valve to replace a six-channel control system, so that the problem of the lifting axle being dragged can be effectively solved in the case that the ASR function is activated due to the drive wheel slipping, the wear between the tire and the road surface is reduced, and the tire and the brake of the lifting axle are protected.

[0011] As a further limitation of the technical scheme of the application, the system further comprises a parking relay valve, a left brake air chamber parking cavity of the drive axle, a right brake air chamber parking cavity of the drive axle, a right brake air chamber parking cavity of the lifting axle and a left brake air chamber parking cavity of the lifting axle.

[0012] The parking relay valve is provided with an air inlet, a control port, a first air outlet and a second air outlet, the air inlet of the parking relay valve is communicated with a parking brake air source port through an air pipe; the control port of the parking relay valve is communicated with a parking brake control port through an air pipe, the first air outlet of the parking relay valve is connected with the left brake air chamber parking cavity of the drive axle and the right brake air chamber parking cavity of the drive axle through air pipes respectively, and the second air outlet of the parking relay valve is connected with the right brake air chamber parking cavity of the lifting axle and the left brake air chamber parking cavity of the lifting axle through air pipes respectively.

[0013] As a further limitation of the technical scheme of the application, the EBS bridge module is provided with a first air inlet and a second air inlet, and the first air inlet and the second air inlet are connected with the service brake air source port through air pipes respectively. The system further comprises an EBS electronic control unit, and the EBS bridge module is connected with the EBS electronic control unit through a CAN line. As a further limitation of the technical scheme of the application, the system further comprises a wheel speed sensor arranged on the left and right tires of the drive axle for detecting the wheel speed; the wheel speed sensor is connected with the EBS bridge module, and the EBS bridge module can judge whether the ASR function is activated after collecting the wheel speed signal of the wheel speed sensor; when the single-side wheel slips, the ASR function of the EBS bridge module is activated.

[0014] The EBS bridge module is provided with the ASR function, and the EBS bridge module can judge whether the ASR function is activated after collecting the wheel speed signal of the wheel speed sensor; when the single-side wheel slips, the ASR function of the EBS bridge module is activated.

[0015] As a further limitation of the technical scheme of the application, the two-position three-way electromagnetic valve is a normally open electromagnetic valve, and is connected with the external EBS electronic control unit through an electric wire and is controlled by the electric signal of the EBS electronic control unit; when the ASR function of the EBS bridge module is activated, the two-position three-way electromagnetic valve receives the electric signal to close the air outlet.

[0016] As a further limitation of the technical scheme of the application, the air outlet of the two-way low selection valve is communicated with the air inlet with lower air pressure among the two air inlets, so as to realize the selection function of the low air pressure end communication, and the air outlet controls the brake chamber service cavity pressure of the lifting axle through the air pipe.

[0017] The brake chamber of the drive axle and the brake chamber of the lifting axle are both spring double-cavity brake chambers, which are divided into brake chamber service cavities and parking cavities, and can be controlled to act respectively through the air pipe.

[0018] The control end of the two-position three-way electromagnetic valve is connected with the EBS electronic control unit; the EBS electronic control unit is further connected with a service brake control port and a parking brake control port respectively; the service brake air source port and the parking brake air source port are connected to the external air source respectively.

[0019] The EBS bridge module is an integrated pressure preparation valve, and under the condition that the EBS electronic control unit cannot work normally, the control port of the EBS bridge module can still receive the air signal caused by the displacement adjustment of the brake pedal, so that the requirement for the service brake function is still met.

[0020] The two-position three-way electromagnetic valve is controlled by the EBS electronic control unit, and when the ASR function is not activated, the two-position three-way electromagnetic valve is in a normally open state, and the air outlet is communicated with the air inlet; when the ASR function is activated, the EBS electronic control unit sends an electric signal to the two-position three-way electromagnetic valve, and the two-position three-way electromagnetic valve closes the air outlet.

[0021] In a second aspect, the present application provides a method for controlling the rear axle brake of a lift vehicle, comprising the following steps: when the vehicle starts or accelerates on a wet road, the single-side wheel slips, the wheel speed sensor on the driving wheel monitors the rotation speed signal, the EBS bridge module collects the rotation speed signal of the wheel speed sensor and sends it to the EBS electronic control unit through the CAN line, the EBS electronic control unit activates the ASR function and sends the signal of the ASR function activation to the two-position three-way electromagnetic valve, the air outlet of the two-position three-way electromagnetic valve is closed, the air pressure of the air outlet of the double-pass low selection valve is consistent with that of the air outlet of the two-position three-way electromagnetic valve, the driving axle brake air chamber has no action, and the driving axle brake does not work, thereby avoiding the occurrence of the dragging phenomenon.

[0022] As a further limitation of the present application, the method further comprises: in the normal driving condition, the service brake is applied, the driving axle wheel does not slip, the wheel speed sensor on the driving wheel monitors the rotation speed signal, the EBS bridge module collects the rotation speed signal of the wheel speed sensor and sends it to the EBS electronic control unit through the CAN line, the EBS electronic control unit does not activate the ASR function, the two-position three-way electromagnetic valve is always open, the air pressure of the air outlet is connected to the air inlet, the air pressure is consistent with that of the service brake air source, the air pressure of the first air inlet of the double-pass low selection valve is lower than that of the second air inlet, the air outlet of the double-pass low selection valve is connected to the first air inlet of the double-pass low selection valve, and the air pressure of the EBS bridge module enters the driving axle brake air chamber through the double-pass low selection valve, thereby the driving axle and the lift axle service brakes work normally.

[0023] As a further limitation of the present application, the method further comprises: when the driver pulls down the hand brake valve during driving to apply the parking brake, the control port of the parking relay valve receives the control air signal from the parking brake air source, the air inlet of the parking relay valve takes air from the parking brake air source, the first air outlet of the parking relay valve and the second air outlet of the parking relay valve are connected to the parking chamber of the driving axle brake air chamber and the parking chamber of the lift axle brake air chamber respectively, and the parking brakes of the two axles work.

[0024] As can be seen from the above technical solutions, the present application has the following advantages: the service brakes of the driving axle and the lift axle adopt a four-channel EBS control system, the EBS bridge module, the two-position three-way electromagnetic valve and the double-pass low selection valve are used to solve the problem of the lift axle dragging caused by the activation of the ASR function, the wear of the lift axle brake and the tire is reduced, and the braking performance and efficiency are improved.

[0025] In addition, the present application has reliable design principles, simple structure and very wide application prospect.

[0026] Therefore, compared with the prior art, the present application has outstanding substantial characteristics and significant progress, and the beneficial effects of its implementation are also obvious. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, for those skilled in the field, other drawings can also be obtained from these drawings without any creative effort.

[0028] Figure 1 is the rear axle brake control principle provided by the embodiment of the present application.

[0029] In the figure, 1-EBS axle module, 2-first two-way low selection valve, 3-lift axle right brake chamber running chamber, 4-second two-way low selection valve, 5-lift axle left brake chamber running chamber, 6-two-position three-way solenoid valve, 7-driving axle right brake chamber running chamber, 8-driving axle left brake chamber running chamber, 9-parking relay valve, 10-lift axle right brake chamber parking chamber, 11-lift axle left brake chamber parking chamber, 12-driving axle right brake chamber parking chamber, 13-driving axle left brake chamber parking chamber, 14-EBS electronic control unit, 15-driving axle right side wheel speed sensor, 16-driving axle left side wheel speed sensor. DETAILED DESCRIPTION

[0030] In order to make the person skilled in the art better understand the technical solutions in the present application, the following will combine the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without any creative effort should be within the scope of protection of the present application.

[0031] As Figure 1 shown, the embodiment of the present application provides a lift vehicle rear axle brake control circuit device, which comprises an EBS axle module 1, a two-position three-way solenoid valve 6, a two-way low selection valve, a driving axle right brake chamber running chamber 7, a driving axle left brake chamber running chamber 8, a lift axle right brake chamber running chamber 3, and a lift axle left brake chamber running chamber 5.

[0032] The two-way low selection valve comprises a first two-way low selection valve 2 and a second two-way low selection valve 4; each two-way low selection valve comprises a first air inlet, a second air inlet and an air outlet.

[0033] The EBS bridge module 1 is provided with an air inlet, the air inlet of the EBS bridge module 1 is communicated with a driving brake air source port, the EBS bridge module 1 is provided with a first air outlet, a second air outlet, a third air outlet and a fourth air outlet, the first air outlet of the EBS bridge module 1 is connected with a driving axle right brake chamber driving cavity 7, the third air outlet of the EBS bridge module 1 is connected with a driving axle left brake chamber driving cavity 8, the second air outlet of the EBS bridge module 1 is communicated with a first air inlet of a first double-pass low selection valve 2, an air outlet of the first double-pass low selection valve 2 is connected with a driving axle right brake chamber driving cavity 3, the fourth air outlet of the EBS bridge module 1 is communicated with a first air inlet of a second double-pass low selection valve 4, an air outlet of the second double-pass low selection valve 4 is connected with a driving axle left brake chamber driving cavity 5; the EBS bridge module 1 is provided with a control port, the control port of the EBS bridge module 1 is communicated with a driving brake control port; it should be noted that the EBS bridge module (1) can independently control two air pressures, can control the driving axle and the driving axle of the lifting axle brake pressure, and is connected with an EBS electric control unit through a CAN line; the EBS bridge module is built-in ASR function, and has a driving anti-skid control system. The EBS bridge module 1 is provided with a first air inlet and a second air inlet, and the first air inlet and the second air inlet are respectively connected with the driving brake air source port through the air pipe.

[0034] The two-position three-way electromagnetic valve 6 is provided with an air inlet and an air outlet; the air inlet of the two-position three-way electromagnetic valve 6 is connected with the driving brake air source port; the air outlet of the two-position three-way electromagnetic valve 6 is communicated with the second air inlet of the first double-pass low selection valve 2 and the second air inlet of the second double-pass low selection valve 4 respectively.

[0035] The system further comprises a wheel speed sensor arranged on the left and right tires of the driving axle for detecting the wheel speed, the wheel speed sensor comprises a driving axle right wheel speed sensor 15 and a driving axle left wheel speed sensor 16, the wheel speed sensor is connected with the EBS bridge module 1, the EBS bridge module can judge whether the ASR function is activated after collecting the wheel speed signal of the wheel speed sensor, when judging that the single wheel slips, the ASR function of the EBS bridge module is activated. When the vehicle starts or accelerates on the wet road, the single wheel slips, the wheel speed sensor on the driving wheel monitors the speed signal, the EBS bridge module collects the wheel speed signal of the wheel speed sensor and sends it to the EBS electric control unit through the CAN line, the EBS electric control unit activates the ASR function, the EBS bridge module can independently control two air pressures, and the driving axle wheel is intermittently braked; the EBS electric control unit sends a signal of the activated ASR function to the two-position three-way electromagnetic valve, the air outlet of the two-position three-way electromagnetic valve is closed, and at the same time, the EBS air outlets 22.2 and 21.1 are connected, and the air pressure is lower than that of the driving brake air source port; at this time, the second air inlet of the double-pass low selection valve is lower than the first air inlet, the output port is connected with the second air inlet, the driving axle brake chamber driving cavity of the lifting axle is not moved, the driving brake of the lifting axle does not work, and the occurrence of the dragging phenomenon is avoided.

[0036] In normal driving conditions, the service brake is applied, the drive axle wheel is not skidding, the wheel speed sensor on the drive wheel monitors the rotational speed signal, the EBS axle module collects the rotational speed signal of the wheel speed sensor and sends it to the EBS electronic control unit through the CAN line, the EBS electronic control unit does not activate the ASR function, the EBS electronic control unit sends an electrical signal to the EBS axle module, the EBS axle module receives the electrical signal, the air inlet takes air from the service brake air source, the air outlets 22, 21 are connected, the service brake chamber of the drive axle is actuated, and the drive axle is braked. At the same time, the EBS air outlets 22.2, 21.1 are connected to the first air inlets of the two double-choke low selection valves, respectively, and the working pressure is limited, the output pressure of the EBS air outlets 22.2, 21.1 is lower than the air pressure of the service brake air source, that is, the first air pressure of the double-choke low selection valve is lower than the air pressure of the service brake air source; the two three-way solenoid valves are in the normal open state, the air pressure of the outlet is connected to the air inlet, and the air pressure is consistent with the air pressure of the service brake air source, so the air pressure of the second air inlet of the double-choke low selection valve is consistent with the air pressure of the service brake air source, the air pressure of the first air inlet of the double-choke low selection valve is lower than that of the second air inlet, and the air pressure of the outlet is connected to the first air inlet, so that the air pressure of the EBS axle module enters the service brake chamber of the lifting axle through the double-choke low selection valve, and the lifting axle is braked.

[0037] In some embodiments, the system further comprises a parking relay valve 9, a left brake chamber parking cavity 13 of the drive axle, a right brake chamber parking cavity 12 of the drive axle, a right brake chamber parking cavity 10 of the lifting axle and a left brake chamber parking cavity 11 of the lifting axle.

[0038] The parking relay valve 9 is provided with an air inlet, a control port, a first air outlet and a second air outlet, and the parking brake air source port is connected to the air inlet of the parking relay valve 9 through an air pipe; the parking brake control port is connected to the control port of the parking relay valve 9 through an air pipe, and the first air outlet of the parking relay valve 9 is connected to the left brake chamber parking cavity 13 of the drive axle and the right brake chamber parking cavity 12 of the drive axle through an air pipe, respectively, and the second air outlet of the parking relay valve 9 is connected to the right brake chamber parking cavity 10 of the lifting axle and the left brake chamber parking cavity 11 of the lifting axle through an air pipe, respectively.

[0039] When the driver pulls down the hand brake valve during driving to apply the parking brake, the control port of the parking relay valve receives the control air signal from the parking brake air source port, the air inlet of the parking relay valve takes air from the parking brake air source, and the first air outlet of the parking relay valve and the second air outlet of the parking relay valve are connected to the drive axle brake chamber parking cavity and the lifting axle brake chamber parking cavity, respectively, and the parking brake of the two axles is applied. In the embodiment of the application, the wheel speed sensor is connected to the EBS axle module 1, the EBS axle module 1 is a rear axle module, and the EBS electronic control unit is connected through the EBS electronic control unit;

[0040] The EBS bridge module has the ASR function, which can judge whether to activate the ASR function after collecting the rotating speed signal of the wheel speed sensor, and the ASR function of the EBS bridge module is activated when one side of the wheel slips. The EBS bridge module is an integrated pressure valve, and under the condition that the EBS control unit cannot work normally, the control port of the EBS bridge module can still receive the air signal caused by the displacement adjustment of the brake pedal, and at this time, the requirement for the service brake function is still met. The EBS control unit controls the EBS bridge module through the CAN line, the wheel speed sensor monitors the wheel speed of the drive axle, and the EBS bridge module collects the wheel speed sensor signal through the wire.

[0041] The four-channel EBS control system provided by the application adds two double-pass low selection valves and a normally open two-position three-way electromagnetic valve to replace the six-channel EBS control system, which can effectively solve the problem of the lifting axle dragging in the case of activating the ASR function of the driving wheel, reduce the wear between the tire and the road surface, and protect the tire and the brake of the lifting axle.

[0042] The two-position three-way electromagnetic valve is a normally open electromagnetic valve, which is connected with the external EBS control unit through a wire and is controlled by the EBS control unit; the two-position three-way electromagnetic valve is provided with an air inlet and an air outlet, the air outlet is always open when the EBS control unit does not act on the air outlet when the ASR function is not activated, and the EBS control unit sends a control signal to control the two-position three-way electromagnetic valve to close the air outlet after the ASR function is activated. When the ASR function of the EBS bridge module is activated, the two-position three-way electromagnetic valve receives the electric signal to close the air outlet.

[0043] The air outlet of the double-pass low selection valve is connected with the air inlet with lower air pressure of the two air inlets, realizing the selection function of low air pressure conduction, and the air outlet controls the service chamber pressure of the brake chamber of the lifting axle through the air pipe. The double-pass low selection valve has two air inlets and an air outlet, the two air inlets are connected with two circuit air paths, and the air outlet is an output control end, and by using the pressure difference principle, when the air pressures of the two air inlets are different, the high air pressure end acts on the piston in the valve to close, and the low air pressure end flows to the air outlet, realizing the function of low air pressure selection conduction. One end of the air inlet of the double-pass low selection valve is connected with the EBS bridge module, and the other end is connected with the air outlet of the two-position three-way electromagnetic valve, and the air outlet is connected with the service chamber of the brake chamber of the lifting axle through the air pipe.

[0044] The EBS control unit is a central controller ECU, which controls and monitors the entire EBS system and provides all control functions such as ABS, ASR, etc., and controls the EBS bridge module through CAN communication.

[0045] The wheel speed sensor is assembled on the left and right tires of the drive axle to monitor the wheel speed, the wheel speed sensor is connected with the EBS axle module, the EBS axle module is built-in ASR function, the EBS axle module sends the speed signal of the wheel speed sensor to the EBS electronic control unit through the CAN line after collection, the EBS electronic control unit can judge whether to activate the ASR function, when the vehicle starts or accelerates on the wet road, the single wheel slips, the EBS electronic control unit activates the ASR function, the EBS axle module can independently control two pressure, and the intermittent braking is carried out on the slipping wheel, so that the stability of the vehicle is improved.

[0046] The relay valve is a parking relay valve, and is provided with a control port, an exhaust port, an air inlet and two air outlets, the control port is controlled by a parking brake air source, and the two air outlets control the brake air chamber parking cavities of the drive axle and the lifting axle through air pipes respectively.

[0047] The EBS axle module is an integrated pressure maintaining valve, under the condition that the EBS electronic control unit cannot work normally, the EBS control port can still receive the air signal caused by the displacement adjustment of the brake pedal; the two-way three-way electromagnetic valve is controlled by the EBS electronic control unit, when the ASR function is not activated, the EBS electronic control unit does not send an electric control signal, and the two-way three-way electromagnetic valve is in a normally open state, and the air outlet is in conduction with the air inlet; when the ASR function is activated, the EBS electronic control unit sends an electric control signal to the two-way three-way electromagnetic valve, and the two-way three-way electromagnetic valve closes the air outlet.

[0048] The double-way low selection valve is a key part for controlling the service brake of the lifting axle, two double-way low selection valves control the service cavities of the left and right brake air chambers of the lifting axle respectively, the air inlets are connected with the air outlets of the EBS axle module and the two-way three-way electromagnetic valve respectively, and the output air pressure of the air outlet depends on the air pressure of the air inlet with lower air pressure.

[0049] The embodiment of the application also provides a lifting vehicle rear axle brake control method, which comprises the following steps: when the vehicle starts or accelerates on the wet road, the single wheel slips, the wheel speed sensor on the drive wheel monitors the speed signal, the EBS axle module sends the speed signal of the wheel speed sensor to the EBS electronic control unit through the CAN line after collection, the EBS electronic control unit activates the ASR function, and sends a signal of the activated ASR function to the two-way three-way electromagnetic valve; the air outlet of the two-way three-way electromagnetic valve is closed, the air pressure of the air outlet of the double-way low selection valve is consistent with that of the air outlet of the two-way three-way electromagnetic valve, the service cavity of the brake air chamber of the lifting axle does not act, and the service brake of the lifting axle does not act.

[0050] In normal driving condition, service brake is applied, drive axle wheel is not skidding, wheel speed sensor on drive wheel monitors rotation speed signal, EBS axle module collects rotation speed signal of wheel speed sensor and sends it to EBS control unit through CAN line, EBS control unit does not activate ASR function, two-position three-way electromagnetic valve is always open, air pressure of outlet is connected to air inlet, air pressure is consistent with air pressure of service brake air source, air pressure of first air inlet of double-way low selection valve is lower than that of second air inlet, outlet of double-way low selection valve is connected to first air inlet of double-way low selection valve, air pressure of EBS axle module enters service brake chamber of lifting axle through double-way low selection valve, service brake of lifting axle and drive axle is normally applied.

[0051] When the driver pulls down the hand brake valve to apply parking brake during driving, the control port of parking relay valve receives control air signal from parking brake air source, the air inlet of parking relay valve takes air from parking brake air source, the first outlet of parking relay valve and the second outlet of parking relay valve are connected to parking brake chamber of drive axle and parking brake chamber of lifting axle respectively, parking brake of two axles is applied.

[0052] The method provided in the embodiment is a control method based on the system provided in the above embodiment.

[0053] Although the present application has been described in detail with reference to the preferred embodiments, the present application is not limited to the preferred embodiments. Various equivalent modifications or replacements can be made to the embodiments of the present application by those skilled in the art without departing from the spirit and essence of the present application, and these modifications or replacements shall be within the scope of the present application. Any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, and these changes or replacements shall be within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A lift truck rear axle brake control system characterized by, The system comprises an EBS bridge module (1), a two-position three-way electromagnetic valve (6) and a double-way low selection valve; the double-way low selection valve comprises a first double-way low selection valve (2) and a second double-way low selection valve (4); each double-way low selection valve comprises a first air inlet, a second air inlet and an air outlet; The EBS bridge module (1) is provided with an air inlet, and the air inlet of the EBS bridge module (1) is communicated with a service brake air source port; the EBS bridge module (1) is provided with a first air outlet, a second air outlet, a third air outlet and a fourth air outlet; the first air outlet of the EBS bridge module (1) is communicated with a right side service brake chamber cavity (7) of a drive axle brake chamber; the third air outlet of the EBS bridge module (1) is communicated with a left side service brake chamber cavity (8) of the drive axle brake chamber; the second air outlet of the EBS bridge module (1) is communicated with the first air inlet of the first double-way low selection valve (2); the air outlet of the first double-way low selection valve (2) is communicated with a right side service brake chamber cavity (3) of a lift axle brake chamber; the fourth air outlet of the EBS bridge module (1) is communicated with the first air inlet of the second double-way low selection valve (4); the air outlet of the second double-way low selection valve (4) is communicated with a left side service brake chamber cavity (5) of the lift axle brake chamber; the EBS bridge module (1) is provided with a control port, and the control port of the EBS bridge module (1) is communicated with a service brake control port through an air pipe; The two-position three-way electromagnetic valve (6) is provided with an air inlet and an air outlet; the air inlet of the two-position three-way electromagnetic valve (6) is connected with the service brake air source port; the air outlet of the two-position three-way electromagnetic valve (6) is respectively communicated with the second air inlet of the first double-way low selection valve (2) and the second air inlet of the second double-way low selection valve (4); The system further comprises wheel speed sensors arranged on the left and right tires of the drive axle for detecting wheel speed; The wheel speed sensors are connected with the EBS bridge module (1); After the EBS bridge module collects the wheel speed signal of the wheel speed sensor, it can be judged whether the ASR function is activated; when a single side wheel slips, the ASR function of the EBS bridge module is activated; The two-position three-way electromagnetic valve is a normally open electromagnetic valve, which is connected with an EBS electronic control unit through an electric wire and is controlled by an electric signal of the EBS electronic control unit; when the ASR function of the EBS bridge module is activated, the two-position three-way electromagnetic valve receives the electric signal to close the air outlet.

2. The lift truck rear axle brake control system of claim 1 wherein, The system further comprises a parking relay valve (9) provided with an air inlet, a control port, a first air outlet and a second air outlet; the air inlet of the parking relay valve (9) is communicated with a parking brake air source port; the control port of the parking relay valve (9) is communicated with a parking brake control port; the first air outlet of the parking relay valve (9) is communicated with a left brake chamber parking cavity (13) of the drive axle and a right brake chamber parking cavity (12) of the drive axle; the second air outlet of the parking relay valve (9) is respectively communicated with a right brake chamber parking cavity (10) of the lift axle and a left brake chamber parking cavity (11) of the lift axle.

3. The lift truck rear axle brake control system of claim 2 wherein, The EBS bridge module (1) is provided with a first air inlet and a second air inlet, and the first air inlet and the second air inlet are respectively connected with the service brake air source port; The system further comprises an EBS electronic control unit, and the EBS bridge module (1) is connected with the EBS electronic control unit through a CAN line.

4. The lift truck rear axle brake control system of claim 3 wherein, The outlet of the double-way low selection valve is communicated with the inlet with lower pressure of the two inlets, realizing the selection function of the low pressure end communication, and the outlet controls the brake chamber running chamber pressure of the lifting bridge through the air pipe.

5. The lift truck rear axle brake control system of claim 3 wherein, The EBS control unit (14) is connected with the control end of the two-position three-way electromagnetic valve (6), and is also connected with the running brake control port and the parking brake control port respectively; the running brake gas source port and the parking brake gas source port are connected to the external gas source.

6. A method for controlling the braking of the rear axle of a lift truck of the type described in any one of claims 1 to 5, characterized in that, The method comprises the following steps: when the vehicle starts or accelerates on a wet road, the single wheel slips, the wheel speed sensor on the driving wheel monitors the rotation speed signal, the EBS bridge module sends the rotation speed signal of the wheel speed sensor to the EBS control unit through the CAN line, the EBS control unit activates the ASR function, and sends the signal of the ASR function activation to the two-position three-way electromagnetic valve; The outlet of the two-position three-way electromagnetic valve is closed, the outlet pressure of the double-way low selection valve is consistent with the outlet pressure of the two-position three-way electromagnetic valve, the running chamber of the brake chamber of the lifting bridge is not actuated, and the running brake of the lifting bridge does not act.

7. The lift truck rear axle brake control method of claim 6 wherein, The method further comprises: under normal driving conditions, the running brake is applied, the driving wheel of the driving bridge does not slip, the wheel speed sensor on the driving wheel monitors the rotation speed signal, the EBS bridge module sends the rotation speed signal of the wheel speed sensor to the EBS control unit through the CAN line, the EBS control unit does not activate the ASR function, the two-position three-way electromagnetic valve is always open, the outlet pressure is communicated with the inlet, the pressure is consistent with the pressure of the running brake gas source port, the pressure of the first inlet of the double-way low selection valve is lower than the pressure of the second inlet, the outlet of the double-way low selection valve is communicated with the first inlet of the double-way low selection valve, the pressure of the EBS bridge module enters the running chamber of the brake chamber of the lifting bridge through the double-way low selection valve, and the running brakes of the lifting bridge and the driving bridge normally act.

8. The lift truck rear axle brake control method of claim 7 wherein, The method further comprises: When the driver pulls down the hand brake valve during driving to apply the parking brake, the control port of the parking relay valve receives the control gas signal from the parking brake gas source port, the inlet of the parking relay valve takes gas from the parking brake gas source, the first outlet of the parking relay valve and the second outlet of the parking relay valve are communicated to the parking chamber of the brake chamber of the driving bridge and the parking chamber of the brake chamber of the lifting bridge respectively, and the parking brakes of the two bridges act.

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