A mechanical control system and control method for a rear active lift bridge

Abstract

The present application discloses a mechanical control system and a control method for a rear active lift bridge, relating to the technical field of vehicle control. The mechanical control system further includes a first overflow valve and a second overflow valve. The first air port of the air suspension solenoid valve is sequentially connected to the first overflow valve and the load-bearing airbag through an air pipe. The first air supply interface of the static break mechanism is connected to the second air port through an air pipe, and the second air supply interface of the static break mechanism is connected to the first air port through an air pipe; the load-bearing airbag and the lifting airbag have the same maximum working pressure value; the air pressure value of the air suspension solenoid valve outlet is greater than the overflow threshold value, and the overflow threshold value is greater than the maximum working pressure value; and when the air suspension solenoid valve works, the working air pressure difference between the two air supply interfaces of the static break mechanism is satisfied. The mechanical control system and the control method of the present application adopt an air circuit mechanical static break mechanism control scheme, which simplifies the control program and has high system reliability.

Description

Technical Field

[0001] This application relates to the technical field of vehicle control, and specifically relates to a mechanical control system and control method for a rear movable lift axle. Background Art

[0002] At present, medium- and long-distance transport vehicles pay great attention to two indicators: load capacity and fuel consumption. They require both a large vehicle load capacity and fuel efficiency. Therefore, to meet this market demand, relevant technicians have designed a vehicle model that can switch between a dual-rear-axle drive form and a single-rear-axle drive form. When the vehicle is fully loaded, the dual-rear-axle drive is adopted to maximize the vehicle load and improve the economic benefits of the whole vehicle operation. When the vehicle is carrying some light goods or is semi-loaded, it switches to the single-rear-axle drive to achieve the best load on the current drive axle, reach the best driving force, and achieve the purpose of fuel saving.

[0003] Specifically, the dual rear axles include a rear fixed lift axle and a rear movable lift axle, and the rear movable lift axle is located at the rearmost of the transport vehicle. Because it involves driving safety, before switching between the dual-rear-axle drive and the single-rear-axle drive, the following conditions must be met: after the rear movable lift axle is combined with or disconnected from the transmission mechanism, the air suspension can lower or lift the rear movable lift axle. Specifically as follows: ① When the vehicle is fully loaded and the dual-rear-axle drive is adopted, in this case, first, the rear movable lift axle is combined with the transmission mechanism through a static break mechanism (when the vehicle is stationary), then the suspension load-bearing airbag is inflated, and at the same time, the lifting airbag is deflated, and the rear movable lift axle descends, and the wheels corresponding to the rear movable lift axle touch the ground, realizing the dual-rear-axle drive; ② When the vehicle is semi-loaded or the load does not exceed the maximum load calibrated for the single-axle drive, the single-rear-axle drive is adopted. In this case, first, the static break mechanism cuts off the connection between the rear movable lift axle and the transmission mechanism, then the suspension load-bearing airbag is deflated, and at the same time, the lifting airbag is inflated, and the rear movable lift axle rises, and the wheels corresponding to the rear movable lift axle are suspended off the ground, and the corresponding rear wheels are lifted off the ground, realizing the single-rear-axle drive.

[0004] In the related art, as Figure 1 shown, the rear movable lift axle mainly adopts an electric control scheme. The air treatment unit is connected to the dual solenoid valve through an air circuit. The dual solenoid valve is connected to the two air supply interfaces of the static break mechanism through two air circuits respectively. The electronic control unit controls the dual solenoid valve, and then controls the air supply of the static break mechanism (the static break mechanism is arranged between the rear movable lift axle and the transmission mechanism) to control the combination and disconnection of the rear movable lift axle and the transmission mechanism, and then realizes the switching between the two drive forms of the dual-bridge drive and the single-bridge drive. Specifically, the two air supply interfaces of the static break mechanism are the first air supply interface and the second air supply interface respectively. When the first air supply interface is inflated and the second air supply interface is deflated, the connection between the rear movable lift axle and the transmission mechanism is cut off; when the first air supply interface is deflated and the second air supply interface is inflated, the rear movable lift axle is connected to the transmission mechanism.

[0005] However, the traditional electronic control scheme has the following problems:

[0006] First, the control program is relatively complex; in the traditional electronic control scheme, it is necessary to ensure that the static break mechanism is disconnected or combined first, and then the lifting and lowering of the lifting axle are carried out, and the sequence is obvious; the static break mechanism needs to be controlled by a dual solenoid valve, and the two air bags are controlled by an air suspension solenoid valve; after the electronic control unit energizes the dual solenoid valve to complete the action of the static break mechanism, it is also necessary to send an instruction to the air suspension solenoid valve to control the charging and discharging of the two air bags; to achieve the above control process, it is necessary to modify the pin program of the electronic control unit, pay attention to the sequence control, and achieve the control process of the static break mechanism first and then the two air bags, which has a high cost and a long time cycle;

[0007] Second, if a failure occurs in the dual solenoid valve itself or in the circuit between the dual solenoid valve and the electronic control unit, the system will fail, and the system reliability is poor. Summary of the Invention

[0008] Aiming at the defects existing in the prior art, the purpose of the present application is to provide a mechanical control system and a control method for a rear movable lifting axle, which adopt an air circuit mechanical static break mechanism control scheme, simplify the control program, and have high system reliability.

[0009] To achieve the above object, the technical solution adopted is: a mechanical control system for a rear movable lifting axle, including an air suspension solenoid valve, a static break mechanism, a load-bearing air bag and a lifting air bag,

[0010] The mechanical control system further includes a first relief valve and a second relief valve, and the air suspension solenoid valve includes a first air port and a second air port that alternately discharge air;

[0011] The first air port is sequentially connected to the first relief valve and the load-bearing air bag through an air pipe, and the second air port is sequentially connected to the second relief valve and the lifting air bag through an air pipe;

[0012] The first air supply interface of the static break mechanism is connected to the second air port through an air pipe, and the second air supply interface of the static break mechanism is connected to the first air port through an air pipe;

[0013] The first relief valve and the second relief valve have the same relief threshold, and the return threshold is zero; the load-bearing air bag and the lifting air bag have the same maximum working pressure value; the air pressure value of the air suspension solenoid valve outlet is greater than the relief threshold, and the relief threshold is greater than the maximum working pressure value; and when the air suspension solenoid valve works, the working air pressure difference between the two air supply interfaces of the static break mechanism is satisfied.

[0014] On the basis of the above technical solution, the mechanical control system further includes an air treatment unit, and the air treatment unit is connected to the air inlet of the air suspension solenoid valve through an air pipe, and the air suspension solenoid valve controls the air flow direction through its first air port and second air port.

[0015] On the basis of the above technical solution, the mechanical control system further includes a lift switch and an electronic control unit, and the lift switch is sequentially connected to the electronic control unit and the air suspension solenoid valve through a circuit; the lift switch sends a switching instruction for single rear axle and double rear axles to the air suspension solenoid valve through the electronic control unit;

[0016] When switching from a single rear axle to a double rear axle, the air suspension solenoid valve receives the switching instruction from the electronic control unit, the first air port inflates the first overflow valve, and the second air port discharges air to the outside; when switching from a double rear axle to a single rear axle, the air suspension solenoid valve receives the switching instruction from the electronic control unit, the first air port discharges air to the outside, and the second air port inflates the second overflow valve.

[0017] On the basis of the above technical solution, the overflow threshold is 7.3 bar, the air pressure value of the air outlet of the air suspension solenoid valve is 12 bar, and the working air pressure difference threshold of the two air supply interfaces of the static break mechanism is 6 bar; the maximum working pressure value inside the load-bearing airbag and the lift airbag is 5.5 bar;

[0018] When the air suspension solenoid valve works, one air port of the air suspension solenoid valve discharges air to the outside, and the other air port inflates one of the overflow valves, and the working air pressure difference between the two air supply interfaces of the static break mechanism is greater than 6 bar.

[0019] On the basis of the above technical solution, both the first overflow valve and the second overflow valve adopt return overflow valves; when the air flow inflates from any air port of the air suspension solenoid valve to the overflow valve and flows to the load-bearing airbag or the lifting airbag, the air flow pressure is greater than the overflow threshold, and the overflow valve is turned on; when the air flow discharges air to the outside from any air port of the air suspension solenoid valve, and the air flow flows from the load-bearing airbag or the lifting airbag through the overflow valve to the air suspension solenoid valve, the air flow pressure is greater than zero, and the overflow valve is turned on.

[0020] This application also discloses a control method based on the above mechanical control system, including the following steps:

[0021] Switching from a single rear axle to a double rear axle, or switching from a double rear axle to a single rear axle;

[0022] The switching from a single rear axle to a double rear axle includes:

[0023] The first air port of the air suspension solenoid valve inflates the static break mechanism through the second air supply interface, the first air supply interface of the static break mechanism discharges air to the outside through the second air port, and after the static break mechanism is connected, the movable lift bridge and the transmission mechanism are connected;

[0024] The first air port of the air suspension solenoid valve inflates the load-bearing airbag through the first overflow valve, and the lifting airbag discharges air externally from the second air port through the second overflow valve; then the rear movable lifting bridge is lowered.

[0025] The switching from the double rear axle to the single rear axle includes:

[0026] The second air port of the air suspension solenoid valve inflates the static break mechanism through the first air supply interface, and the second air supply interface of the static break mechanism discharges air externally through the second air port. After the static break mechanism disconnects, the rear movable lifting bridge and the transmission mechanism are separated;

[0027] The second air port of the air suspension solenoid valve inflates the lifting airbag through the second overflow valve, and the load-bearing airbag discharges air externally from the first air port through the first overflow valve; then the rear movable lifting bridge rises.

[0028] Based on the above technical solution, the mechanical control system further includes an air treatment unit, and the air treatment unit is connected to the air inlet of the air suspension solenoid valve through an air pipe; the air suspension solenoid valve controls the air flow direction through its first air port and second air port.

[0029] Based on the above technical solution, the mechanical control system further includes a lifting switch and an electronic control unit, and the lifting switch is sequentially connected to the electronic control unit and the air suspension solenoid valve through a circuit; the lifting switch sends switching instructions for the single rear axle and the double rear axle to the air suspension solenoid valve through the electronic control unit;

[0030] When switching from the single rear axle to the double rear axle, it includes:

[0031] The lifting switch sends a switching instruction from the single rear axle to the double rear axle to the electronic control unit;

[0032] The electronic control unit controls the air suspension solenoid valve according to the switching instruction;

[0033] Or, when switching from the double rear axle to the single rear axle, it includes:

[0034] The lifting switch sends a switching instruction from the double rear axle to the single rear axle to the electronic control unit;

[0035] The electronic control unit controls the air suspension solenoid valve according to the switching instruction.

[0036] Based on the above technical solution, the overflow threshold is 7.3 bar, the air pressure value of the air suspension solenoid valve outlet is 12 bar, and the working air pressure difference threshold of the two air supply interfaces of the static break mechanism is 6 bar; the maximum working pressure value inside the load-bearing airbag and the lifting airbag is 5.5 bar;

[0037] When the air suspension solenoid valve works, one air port of the air suspension solenoid valve discharges air externally, and the other air port inflates one of the overflow valves, and the working air pressure difference between the two air supply interfaces of the static cut-off mechanism is greater than 6 bar.

[0038] On the basis of the above technical solution, both the first overflow valve and the second overflow valve adopt return overflow valves; when the air flow inflates the overflow valve from any air port of the air suspension solenoid valve and flows to the load-bearing airbag or the lifting airbag, the air flow pressure is greater than the overflow threshold, and the overflow valve is turned on; when the air flow discharges air externally from any air port of the air suspension solenoid valve, and the air flow flows from the load-bearing airbag or the lifting airbag through the overflow valve to the air suspension solenoid valve, the air flow pressure is greater than zero, and the overflow valve is turned on.

[0039] The beneficial effects brought by the technical solution provided by this application include:

[0040] The mechanical control system and control method of this application integrate the control air circuits of the static cut-off mechanism and two airbags, reduce the original two electric control programs (first the double solenoid valve and then the air suspension solenoid valve) to one electric control program (the air suspension solenoid valve), improve the control efficiency, reduce the electrical component of the double solenoid valve, add two solenoid valves, and overall reduce the cost; at the same time, integrate the static cut-off mechanism control and the airbag control together, with faster response, reduced circuit, reduced failure rate, and the air circuit control is more stable than the circuit control, and the system has high reliability.

[0041] The key factor in the integration of the mechanical control system of this application is to make clever use of the relative magnitudes of the overflow threshold, the working air pressure difference, and the maximum working pressure value. The air pressure value at the outlet of the air suspension solenoid valve is greater than the overflow threshold, the overflow threshold is greater than the maximum working pressure value, and the working air pressure difference between the two air supply interfaces of the static cut-off mechanism is satisfied when the air suspension solenoid valve works. When the first air port of the air suspension solenoid valve inflates the static cut-off mechanism through the second air supply interface, the first air supply interface discharges air through the second air port, and the air pressure difference between the two air supply interfaces satisfies its own two air supply interfaces, and the static cut-off mechanism is connected to the movable lifting bridge and the transmission mechanism after being connected; almost at the same time, when the first air port of the air suspension solenoid valve inflates the load-bearing airbag through the first overflow valve, the lifting airbag discharges air externally through the second overflow valve through the second air port, and the rear movable lifting bridge descends; more importantly, the air circuit of the static cut-off mechanism is closer to the air suspension solenoid valve, and the state switching of the static cut-off mechanism takes precedence over the inflation and deflation of the two airbags. The integrated control air circuit automatically satisfies the control of the static cut-off mechanism first and then the two airbags. The design is ingenious, and the cost performance of the circuit and air circuit is high. Description of the Drawings

[0042] To more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the accompanying drawings required for the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0043] Figure 1 is the electric control system of the rear movable lifting bridge in the prior art;

[0044] Figure 2 is the mechanical control system of the rear movable lifting bridge provided by the embodiments of the present application.

[0045] Reference numerals: 1, air suspension solenoid valve; 11, first air port; 12, second air port; 2, static cut-off mechanism; 21, first air supply interface; 22, second air supply interface. Detailed implementation manners

[0046] In order to make the purpose, technical solutions and advantages of the present application more clear, the following further details the present invention in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0047] As Figure 2 shown, an embodiment of a mechanical control system of a rear movable lifting bridge is disclosed in the present application. The air circuit mechanical static cut-off mechanism control scheme is adopted, which simplifies the control program, has a low air circuit failure rate, and high system reliability.

[0048] Specifically, the double rear axles include a rear fixed lifting bridge and a rear movable lifting bridge, and the rear movable lifting bridge is located at the rearmost of the transport vehicle; the technical solution of the present application mainly aims at the rear movable lifting bridge.

[0049] The mechanical control system of the rear movable lifting bridge includes an air suspension solenoid valve 1, a static cut-off mechanism 2, a load-bearing airbag and a lifting airbag. The mechanical control system also includes a first overflow valve and a second overflow valve, which are special structures newly added in the present application. The air suspension solenoid valve 1 includes a first air port 11 and a second air port 12 that alternately discharge air. The first air port 11 is sequentially connected to the first overflow valve and the load-bearing airbag through an air pipe, and the second air port 12 is sequentially connected to the second overflow valve and the lifting airbag through an air pipe.

[0050] Specifically, the first air port 11, the first overflow valve and the load-bearing airbag form a first branch, and the second air port 12, the second overflow valve and the lifting airbag form a second branch. When the first branch is inflated, the second branch exhausts; when the first branch exhausts, the second branch is inflated.

[0051] The first air supply interface 21 of the static cut-off mechanism 2 is connected to the second air port 12 through an air pipe, and the second air supply interface 22 of the static cut-off mechanism 2 is connected to the first air port 11 through an air pipe.

[0052] The first overflow valve and the second overflow valve have the same overflow threshold value, and the return threshold value is zero; that is, when flowing forward, the first branch and the second branch are inflated, and the air flow pressure value must be greater than the overflow threshold value to be inflated normally. When flowing backward, the first branch and the second branch exhaust air (exhaust through the first air port 11 and the second air port 12), and the resistance formed by the first overflow valve and the second overflow valve is zero, and the lifting airbag and the load-bearing airbag can directly exhaust air.

[0053] The load-bearing airbag and the lifting airbag have the same maximum working pressure value; the air pressure value of the air suspension solenoid valve outlet is greater than the overflow threshold value, and the overflow threshold value is greater than the maximum working pressure value; and when the air suspension solenoid valve works, it satisfies the working air pressure difference between the two air supply interfaces of the static cut-off mechanism, that is, the actual air pressure difference between the two air supply interfaces of the static cut-off mechanism is greater than its own working air pressure difference threshold value.

[0054] Relatively speaking, in the existing electronic control scheme, it is necessary to first control the static cut-off mechanism through a double solenoid valve, and then control the two airbags through the air suspension solenoid valve; the control of the static cut-off mechanism is mainly in an electronic control manner, and the double solenoid valve and the air suspension solenoid valve need to be in a strict time sequence, first control the static cut-off mechanism, and then control the airbag. However, the mechanical control system of the present application combines the two, integrates the control air circuits of the static cut-off mechanism and the two airbags, reduces the original two electronic control programs (first the double solenoid valve and then the air suspension solenoid valve) to one electronic control program (the air suspension solenoid valve), improves the control efficiency, reduces the electrical component of the double solenoid valve, adds two solenoid valves, and overall reduces the cost; at the same time, integrating the control of the static cut-off mechanism and the airbag control together, the response is faster, the circuit is reduced, the failure rate is reduced, the air circuit control is more stable than the circuit control, and the system reliability is high.

[0055] The key factor in the integration of the mechanical control system of this application lies in the ingenious utilization of the relative magnitudes of the overflow threshold, the working air pressure difference, and the maximum working pressure value. The air pressure value at the outlet of the air suspension solenoid valve is greater than the overflow threshold, the overflow threshold is greater than the maximum working pressure value, and when the air suspension solenoid valve operates, the actual air pressure difference between the two air supply interfaces of the static cut-off mechanism is greater than its working air pressure difference threshold. When the first air port 11 of the air suspension solenoid valve 1 inflates the static cut-off mechanism through the second air supply interface 22, the first air supply interface 21 deflates through the second air port 12, and the air pressure difference between the two air supply interfaces satisfies that of its own two air supply interfaces, the static cut-off mechanism is connected to the movable lift bridge and the transmission mechanism after being connected; almost simultaneously, when the first air port 11 of the air suspension solenoid valve 1 inflates the load-bearing airbag through the first overflow valve, the lifting airbag deflates to the outside through the second overflow valve through the second air port 12, and then the movable lift bridge descends; more importantly, the air path of the static cut-off mechanism is closer to the air suspension solenoid valve, the state switching of the static cut-off mechanism takes precedence over the inflation and deflation of the two airbags, and the integrated control air path automatically satisfies the control of the static cut-off mechanism first and then the two airbags. The design is ingenious, and the cost performance of the circuit and air path is high.

[0056] In one embodiment, the mechanical control system further includes an air treatment unit. The air treatment unit is connected to the air inlet of the air suspension solenoid valve through an air pipe, and the air suspension solenoid valve controls the air flow direction through its first air port and second air port. During actual use, after the air flow enters the air inlet of the air suspension solenoid valve, it inflates the airbag through one of the first air port and the second air port, and the other air port is used for exhaust.

[0057] In one embodiment, the mechanical control system further includes a lift switch and an electronic control unit. The lift switch is sequentially connected to the electronic control unit and the air suspension solenoid valve 1 through a circuit; the lift switch sends a switching instruction for single rear axle and double rear axle to the air suspension solenoid valve 1 through the electronic control unit, and the air suspension solenoid valve 1 controls the corresponding first air port 11 or second air port 12 to inflate according to the switching instruction. Specifically, when switching from single rear axle to double rear axle, the first air port 11 inflates the first branch; when switching from double rear axle to single rear axle, the second air port 12 inflates the second branch.

[0058] The mechanical control system of this application simplifies the connection circuit of the electronic control unit compared with the prior art solution. In the prior art solution, the electronic control unit is respectively connected to the static cut-off mechanism, the dual solenoid valve, and the air suspension solenoid valve through circuits; while in the mechanical control system of this application, the electronic control unit is only connected to the air suspension solenoid valve through one circuit, simplifying the circuit, simplifying the control program, reducing the circuit failure rate, and making the air path control safer and more reliable.

[0059] When switching from a single rear axle to a double rear axle, the air suspension solenoid valve 1 receives a switching command from the electronic control unit for switching from a single rear axle to a double rear axle. The first air port 11 inflates the load-bearing airbag through the first overflow valve, and the second air port 12 discharges air externally, thereby controlling the static break mechanism and the two airbags. Specifically, the lifting airbag discharges air externally from the second air port 12 through the second overflow valve. At this time, the air flow reversely flows through the second overflow valve, and the reflux threshold is zero, and the second overflow valve has basically no resistance.

[0060] When switching from a double rear axle to a single rear axle, the air suspension solenoid valve 1 receives a switching command from the electronic control unit for switching from a double rear axle to a single rear axle. The first air port 11 discharges air externally, and the second air port 12 inflates the second overflow valve, thereby controlling the static break mechanism and the two airbags.

[0061] Furthermore, the overflow threshold is 7.3 bar, the air pressure value of the air suspension solenoid valve outlet is 12 bar, and the working air pressure difference threshold of the two air supply interfaces of the static break mechanism 2 is 6 bar; the maximum working pressure value inside the load-bearing airbag and the lifting airbag is 5.5 bar;

[0062] When the air suspension solenoid valve works, one air port of the air suspension solenoid valve discharges air externally, and the other air port inflates one of the overflow valves. During this process, the working air pressure difference between the two air supply interfaces of the static break mechanism 2 is greater than 6 bar, that is, the working air pressure difference of the static break mechanism 2 starts to work and performs a state switch, that is, the static break mechanism 2 connects or cuts off the rear lift axle and the transmission mechanism.

[0063] In one embodiment, both the first overflow valve and the second overflow valve adopt a reflux overflow valve, and the reflux overflow valve can satisfy that the resistance of reflux is zero.

[0064] When the air flow inflates from any air port of the air suspension solenoid valve 1 to the overflow valve and flows to the load-bearing airbag or the lifting airbag, the air flow pressure is greater than the overflow threshold, and the overflow valve is turned on; when the air flow discharges air externally from any air port of the air suspension solenoid valve 1, and the air flow flows from the load-bearing airbag or the lifting airbag through the overflow valve to the air suspension solenoid valve 1, the air flow pressure is greater than zero, and the overflow valve is turned on.

[0065] This application also discloses an embodiment of a control method based on the above mechanical control system, which includes the following steps:

[0066] Switching from a single rear axle to a double rear axle, or switching from a double rear axle to a single rear axle;

[0067] Switching from a single rear axle to a double rear axle includes:

[0068] The first air port 11 of the air suspension solenoid valve 1 inflates the static break mechanism 2 through the second air supply interface 22, the first air supply interface 21 of the static break mechanism 2 discharges air externally through the second air port 12, and after the static break mechanism 2 is connected, the rear lift axle and the transmission mechanism are connected to realize double rear axle drive;

[0069] The first air port 11 of the air suspension solenoid valve 1 inflates the load-bearing airbag through the first overflow valve. The lifting airbag deflates to the outside through the second overflow valve from the second air port 12, and then the rear movable lifting bridge is lowered, and the tires corresponding to the rear movable lifting bridge touch the ground.

[0070] The switching from a double rear axle to a single rear axle includes:

[0071] The second air port 12 of the air suspension solenoid valve 1 inflates the static break mechanism 2 through the first air supply interface 21. The second air supply interface 22 of the static break mechanism 2 deflates to the outside through the second air port 12. After the static break mechanism 2 disconnects the rear movable lifting bridge and the transmission mechanism, single rear axle drive is achieved.

[0072] The second air port 12 of the air suspension solenoid valve 1 inflates the lifting airbag through the second overflow valve. The load-bearing airbag deflates to the outside from the first air port 11 through the first overflow valve; the rear movable lifting bridge rises, and the tires corresponding to the rear movable lifting bridge leave the ground and hang in the air, which not only meets the vehicle load but also reduces the wear and fuel consumption of the corresponding tires.

[0073] The control method of the mechanical control system of the present application integrates the control air circuits of the static break mechanism and the two airbags, reduces the original two electric control programs (first the double solenoid valve and then the air suspension solenoid valve) to one electric control program (the air suspension solenoid valve), improves the control efficiency, reduces the electrical component of the double solenoid valve, adds two solenoid valves, and overall reduces the cost; at the same time, integrating the control of the static break mechanism and the airbag control together results in a faster response, reduces the circuit, reduces the failure rate, and the air circuit control is more stable than the circuit control, with high system reliability.

[0074] The key factor in the integration of the control method of the mechanical control system of the present application lies in the ingenious utilization of the relative magnitudes of the overflow threshold, the working air pressure difference, and the maximum working pressure value. The air pressure value at the outlet of the air suspension solenoid valve is greater than the overflow threshold, the overflow threshold is greater than the maximum working pressure value, and the actual air pressure difference between the two air supply interfaces of the static break mechanism when the air suspension solenoid valve is working is greater than its own working air pressure difference threshold. When the first air port 11 of the air suspension solenoid valve 1 inflates the static break mechanism through the second air supply interface 22, the first air supply interface 21 deflates through the second air port 12, and the air pressure difference between the two air supply interfaces satisfies its own two air supply interfaces, the static break mechanism connects the rear movable lifting bridge and the transmission mechanism; almost simultaneously, when the first air port 11 of the air suspension solenoid valve 1 inflates the load-bearing airbag through the first overflow valve, the lifting airbag deflates to the outside through the second overflow valve through the second air port 12, and the rear movable lifting bridge descends; more importantly, the air circuit of the static break mechanism is closer to the air suspension solenoid valve, and the state switching of the static break mechanism takes precedence over the inflation and deflation of the two airbags. The integrated control air circuit automatically satisfies the requirement of controlling the static break mechanism first and then the two airbags, with ingenious design and high cost performance of the circuit and air circuit.

[0075] In one embodiment, the mechanical control system further includes an air handling unit. The air handling unit is connected to the air inlet of the air suspension solenoid valve through an air pipe. The air suspension solenoid valve controls the air flow direction through its first air port and second air port. During actual use, after the air flow enters the air inlet of the air suspension solenoid valve, it inflates the airbag through one of the first air port and the second air port, and the other air port is used for exhaust.

[0076] In one embodiment, the mechanical control system further includes a lift switch and an electronic control unit. The lift switch is sequentially connected to the electronic control unit and the air suspension solenoid valve 1 through a circuit; the lift switch sends a switching instruction for single rear axle and double rear axles to the air suspension solenoid valve 1 through the electronic control unit. The air suspension solenoid valve 1 controls the corresponding first air port 11 or second air port 12 to inflate according to the switching instruction. Specifically, when switching from single rear axle to double rear axle, the first air port 11 inflates the first branch; when switching from double rear axle to single rear axle, the second air port 12 inflates the second branch.

[0077] When switching from single rear axle to double rear axle, it includes:

[0078] The lift switch sends a switching instruction from single rear axle to double rear axle to the electronic control unit;

[0079] The electronic control unit controls the air suspension solenoid valve 1 according to the switching instruction, and then performs subsequent control.

[0080] Or, when switching from double rear axle to single rear axle, it includes:

[0081] The lift switch sends a switching instruction from double rear axle to single rear axle to the electronic control unit;

[0082] The electronic control unit controls the air suspension solenoid valve 1 according to the switching instruction, and then performs subsequent control.

[0083] In one embodiment, the overflow threshold is 7.3 bar, the air pressure value at the outlet of the air suspension solenoid valve is 12 bar, and the working air pressure difference threshold between the two air supply interfaces of the static break mechanism 2 is 6 bar; the maximum working pressure value inside the load-bearing airbag and the lift airbag is 5.5 bar;

[0084] When the air suspension solenoid valve works, one air port of the air suspension solenoid valve discharges air to the outside, and the other air port inflates one of the overflow valves. The working air pressure difference between the two air supply interfaces of the static break mechanism 2 is greater than 6 bar, that is, the static break mechanism 2 enters the working state and performs state switching. The static break mechanism 2 connects or disconnects the rear lift axle and the transmission mechanism.

[0085] In one embodiment, both the first overflow valve and the second overflow valve adopt a return overflow valve, and the return overflow valve can meet the requirement that the resistance of the return flow is zero.

[0086] When the air flow inflates the overflow valve from any air port of the air suspension solenoid valve 1 and flows towards the load-bearing airbag or the lifting airbag, the air flow pressure is greater than the overflow threshold value, and the overflow valve is turned on; when the air flow discharges externally from any air port of the air suspension solenoid valve 1, and the air flow flows from the load-bearing airbag or the lifting airbag through the overflow valve to the air suspension solenoid valve 1, the air flow pressure is greater than zero, and the overflow valve is turned on.

[0087] In the description of the present application, it should be noted that the orientation or positional relationship indicated by terms such as "upper" and "lower" is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application. Unless otherwise clearly specified and defined, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0088] It should be noted that in the present application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element.

[0089] The above are only specific embodiments of the present application, enabling those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A mechanical control system for a rear active lift bridge, comprising an air suspension solenoid valve, a static break mechanism, a load-bearing airbag, and a lifting airbag, characterized in that: The mechanical control system further includes a first overflow valve and a second overflow valve. The air suspension solenoid valve (1) includes a first air port (11) and a second air port (12) that alternately discharge and release air; The first air port (11) is sequentially connected to the first overflow valve and the load-bearing airbag through an air pipe, and the second air port (12) is sequentially connected to the second overflow valve and the lifting airbag through an air pipe; The first air supply interface (21) of the static break mechanism (2) is connected to the second air port (12) through an air pipe, and the second air supply interface (22) of the static break mechanism (2) is connected to the first air port through an air pipe; The first overflow valve and the second overflow valve have the same overflow threshold, and the return threshold is zero; the load-bearing airbag and the lifting airbag have the same maximum working pressure value; the air pressure value of the air suspension solenoid valve outlet is greater than the overflow threshold, and the overflow threshold is greater than the maximum working pressure value; and when the air suspension solenoid valve works, it satisfies the working air pressure difference between the two air supply interfaces of the static break mechanism.

2. The mechanical control system of a rear active lift bridge according to claim 1, characterized in that: The mechanical control system further includes an air treatment unit, which is connected to the air inlet of the air suspension solenoid valve through an air pipe, and the air suspension solenoid valve controls the air flow direction through its first air port (11) and second air port (12).

3. The mechanical control system of a rear active lifting bridge according to claim 1, characterized in that: The mechanical control system further includes a lift switch and an electronic control unit. The lift switch is sequentially connected to the electronic control unit and the air suspension solenoid valve (1) through a circuit; the lift switch sends a switching instruction for single rear axle and double rear axle to the air suspension solenoid valve (1) through the electronic control unit; When switching from single rear axle to double rear axle, the air suspension solenoid valve (1) receives the switching instruction from the electronic control unit, the first air port (11) inflates the first overflow valve, and the second air port (12) discharges air to the outside; when switching from double rear axle to single rear axle, the air suspension solenoid valve (1) receives the switching instruction from the electronic control unit, the first air port (11) discharges air to the outside, and the second air port (12) inflates the second overflow valve.

4. The mechanical control system of a rear active lift bridge according to claim 1, characterized in that: The overflow threshold is 7.3 bar, the air pressure value of the air suspension solenoid valve outlet is 12 bar, and the working air pressure difference threshold between the two air supply interfaces of the static break mechanism (2) is 6 bar; the maximum working pressure value inside the load-bearing airbag and the lifting airbag is 5.5 bar; When the air suspension solenoid valve works, one air port of the air suspension solenoid valve discharges air to the outside, and the other air port inflates one of the overflow valves, and the working air pressure difference between the two air supply interfaces of the static break mechanism (2) is greater than 6 bar.

5. The mechanical control system of a rear active lifting bridge according to claim 1, characterized in that: Both the first overflow valve and the second overflow valve adopt return overflow valves; when the air flow inflates from any air port of the air suspension solenoid valve (1) to the overflow valve and flows to the load-bearing airbag or the lifting airbag, the air flow pressure is greater than the overflow threshold, and the overflow valve is turned on; when the air flow discharges air to the outside from any air port of the air suspension solenoid valve (1), and the air flow flows from the load-bearing airbag or the lifting airbag through the overflow valve to the air suspension solenoid valve (1), the air flow pressure is greater than zero, and the overflow valve is turned on.

6. A control method for the mechanical control system according to claim 1, characterized in that, It includes the following steps: Switch from a single rear axle to a double rear axle, or from a double rear axle to a single rear axle; The switch from a single rear axle to a double rear axle includes: The first air port (11) of the air suspension solenoid valve (1) inflates the static break mechanism (2) through the second air supply interface (22), the first air supply interface (21) of the static break mechanism (2) exhausts to the outside through the second air port (12), and after the static break mechanism (2) is connected, the movable lifting bridge and the transmission mechanism are connected; The first air port (11) of the air suspension solenoid valve (1) inflates the load-bearing airbag through the first overflow valve, and the lifting airbag exhausts to the outside through the second overflow valve from the second air port (12); the rear movable lifting bridge is lowered; The switch from a double rear axle to a single rear axle includes: The second air port (12) of the air suspension solenoid valve (1) inflates the static break mechanism (2) through the first air supply interface (21), the second air supply interface (22) of the static break mechanism (2) exhausts to the outside through the second air port (12), and after the static break mechanism (2) is disconnected, the rear movable lifting bridge and the transmission mechanism are disconnected; The second air port (12) of the air suspension solenoid valve (1) inflates the lifting airbag through the second overflow valve, and the load-bearing airbag exhausts to the outside through the first overflow valve from the first air port (11); the rear movable lifting bridge rises.

7. The control method of the mechanical control system according to claim 6, characterized in that: The mechanical control system further includes an air treatment unit, and the air treatment unit is connected to the air inlet of the air suspension solenoid valve through an air pipe; the air suspension solenoid valve (1) controls the air flow direction through its first air port (11) and second air port (12).

8. The mechanical control system of a rear active lift bridge according to claim 6, characterized in that: The mechanical control system further includes a lifting switch and an electronic control unit, and the lifting switch is sequentially connected to the electronic control unit and the air suspension solenoid valve (1) through a circuit; the lifting switch sends a switching instruction for a single rear axle and a double rear axle to the air suspension solenoid valve (1) through the electronic control unit; When switching from a single rear axle to a double rear axle, it includes: The lifting switch sends a switching instruction for switching from a single rear axle to a double rear axle to the electronic control unit; The electronic control unit controls the air suspension solenoid valve (1) according to the switching instruction; Or, when switching from a double rear axle to a single rear axle, it includes: The lifting switch sends a switching instruction for switching from a double rear axle to a single rear axle to the electronic control unit; The electronic control unit controls the air suspension solenoid valve (1) according to the switching instruction.

9. The mechanical control system of a rear active lifting bridge according to claim 6, characterized in that: The overflow threshold is 7.3 bar, the air pressure value of the air suspension solenoid valve outlet is 12 bar, and the working air pressure difference threshold of the two air supply interfaces of the static break mechanism (2) is 6 bar; the maximum working pressure value inside the load-bearing airbag and the lifting airbag is 5.5 bar; When the air suspension solenoid valve works, one air port of the air suspension solenoid valve exhausts to the outside, and the other air port inflates one of the overflow valves, and the working air pressure difference between the two air supply interfaces of the static break mechanism (2) is greater than 6 bar.

10. A mechanical control system for a rear active lift axle, as claimed in claim 6, characterized in that: Both the first overflow valve and the second overflow valve adopt return overflow valves; when air flows from any air port of the air suspension solenoid valve (1) to the overflow valve and then flows to the load-bearing airbag or the lifting airbag, the air flow pressure is greater than the overflow threshold value, and the overflow valve is turned on; when air is exhausted from any air port of the air suspension solenoid valve (1) and the air flow passes through the overflow valve from the load-bearing airbag or the lifting airbag to the air suspension solenoid valve (1), the air flow pressure is greater than zero, and the overflow valve is turned on.

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