Electro-hydraulic proportional lifting control device of mining dump truck and using method

Abstract

The invention discloses an electro-hydraulic proportional lifting control device for a mining dump truck. The electro-hydraulic proportional lifting control device comprises a hydraulic oil tank, a first oil suction filter screen, a lifting oil pump, a lifting valve group, a left lifting oil cylinder, a right lifting oil cylinder, a second oil suction filter screen and a control oil pump. The invention discloses a using method of an electric-hydraulic proportional lifting control device of a mining dump truck. The operation mode of the main lifting valve is controlled by the pilot proportional valve, the impact force of the lifting action on the lifting oil cylinder and the frame is effectively reduced, meanwhile, the pressure set value of an outlet of the lifting oil pump is changed along with the load pressure, the front-back pressure difference of the main lifting valve is kept at a constant value, the stability of the carriage lifting speed is improved, and the safety of the carriage is guaranteed. The energy loss of the lifting system is effectively reduced, and the operation economy of the vehicle is improved.

Description

Technical Field

[0001] The invention belongs to the field of mining dump trucks, and in particular relates to an electro-hydraulic proportional lifting control device for a mining dump truck and a use method thereof. Background Art

[0002] Mining dump trucks are off-road dump trucks, mainly used for the transportation of ores and mineral materials in large open-pit mines. Mining dump trucks are mainly composed of a frame, engine, transmission box, rear axle, cab assembly, lifting cylinder, lifting control device, etc. Among them, the lifting control device is an important component of the mining dump truck, especially has a vital impact on the working reliability and safety of the dump truck.

[0003] At present, the lifting control device of a mining dump truck is generally composed of a main lifting valve, a lifting pilot valve, a lifting handle and hydraulic pipelines. The oil from the lifting oil pump enters the lifting cylinder through the main lifting valve. The driver operates the lifting handle to control the main lifting valve to realize the four actions of lifting, lowering, holding and floating of the dump truck compartment. However, this operation method has a great impact on the lifting cylinder and the frame, and the driver's operating action is not flexible. In addition, this lifting system has large energy loss, serious system heat generation, and uses a lot of hydraulic pipelines, which has certain safety risks. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides an electro-hydraulic proportional lifting control device and a method for using a mining dump truck, in which the operation mode of the main lifting valve is controlled by a pilot proportional valve, which effectively reduces the impact force of the lifting action on the lifting cylinder and the frame, and at the same time changes the outlet pressure setting value of the lifting oil pump with the load pressure, so that the pressure difference before and after the main lifting valve is maintained at a constant value, thereby improving the stability of the lifting speed of the car body, effectively reducing the energy loss of the lifting system, and improving the operating economy of the vehicle.

[0005] To achieve the above purpose, the technical solution used in the present invention is:

[0006] The electro-hydraulic proportional lifting control device for mining dump trucks includes:

[0007] A hydraulic oil tank, used to store oil;

[0008] The lifting oil pump takes power from the power output end of the engine and is used to provide lifting oil pressure. Its oil suction port is connected to the hydraulic oil tank through a pipeline, and its oil outlet is connected to the power oil inlet of the lifting valve group through a pipeline;

[0009] The lifting valve group is used to transmit the lifting power of the lifting oil pump to the left lifting cylinder and the right lifting cylinder. The first oil outlet is connected to the lowering port of the left lifting cylinder and the right lifting cylinder through pipelines, and the second oil outlet is connected to the lifting port of the left lifting cylinder and the right lifting cylinder through pipelines. The main oil return port and the oil discharge port are connected to the hydraulic oil tank through pipelines. The lifting valve group adopts an integrated valve group, including: a pressure reducing valve, a first pilot proportional valve, a second pilot proportional valve, a main lifting valve, a hydraulic control valve, and a relief valve.

[0010] A pressure reducing valve, used to reduce the control oil pressure to a set value and deliver it to the first pilot proportional valve and the second pilot proportional valve, wherein the oil inlet is connected to the pilot oil inlet of the lift valve group through a pipeline, the oil outlet is connected to the oil inlet of the first pilot proportional valve and the second pilot proportional valve respectively, and the overflow port is connected to the oil discharge port through a pipeline;

[0011] The first pilot proportional valve and the second pilot proportional valve receive the output pressure command of the vehicle controller, and output or cut off the pressure oil according to the output pressure command. The oil outlet of the first pilot proportional valve is connected to the first control port of the main lift valve through a pipeline, and the oil outlet of the second pilot proportional valve is connected to the second control port of the main lift valve through a pipeline.

[0012] The main lift valve is used to form pressure oil at the first oil outlet and the second oil outlet, and to form a pressure difference between the first oil outlet and the second oil outlet; its oil inlet is connected to the oil inlet of the main lift valve through a pipeline, the first main lift valve oil outlet is connected to the first oil outlet through a pipeline, the second main lift valve oil outlet is connected to the second oil outlet through a pipeline, and the oil return port is connected to the main oil return port through a pipeline;

[0013] A hydraulically controlled valve, used to maintain a constant pressure difference between the oil inlet of the main lift valve and the oil outlet of the first main lift valve and the oil outlet of the second main lift valve, wherein the oil inlet is connected to the first detection port and the second detection port of the main lift valve through pipelines, and the oil outlet is connected to the oil inlet of the cut-off valve through a pipeline;

[0014] The cut-off valve receives the output pressure command of the vehicle controller, outputs or cuts off the pressure oil according to the output pressure command, and its oil inlet is connected to the control ports of the first unloading valve and the second unloading valve through pipelines, and its oil outlet is connected to the oil drain port through pipelines;

[0015] The first unloading valve and the second unloading valve are solenoid valves, whose oil outlets are connected to the main oil return port through pipelines, and whose oil inlets are connected to the oil outlet of the lifting oil pump through pipelines, and are used to connect or disconnect the connection between the lifting oil pump and the hydraulic oil tank;

[0016] The control oil pump takes power from the power output end of the engine to form the control oil pressure and transmit the control oil pressure to the pilot oil inlet of the lifting valve group. Its oil suction port is connected to the hydraulic oil tank through a pipeline, and its oil outlet is connected to the oil inlet of the lifting valve group through a pipeline.

[0017] Furthermore, the oil outlet of the hydraulic control valve is connected to the oil inlet of the overflow valve and the control ports of the first unloading valve and the second unloading valve through pipelines; when the car body is lifted, the load pressure of the left lifting cylinder and the right lifting cylinder is transmitted to the outlet of the lifting oil pump to control the opening of the first unloading valve and the second unloading valve so that the pressure difference before and after the main lifting valve remains constant; the control port of the hydraulic control valve is connected to the second control port through a pipeline, and the valve core position is adjusted by the pressure of the second control port to keep the pressure difference before and after the main lifting valve stable.

[0018] Furthermore, the oil outlet of the hydraulic control valve is connected to the third damping hole through a pipeline, and the third damping hole is connected to the control ports of the first unloading valve and the second unloading valve through a pipeline. The third damping hole is used to prevent the load pressure fluctuation fed back by the hydraulic control valve from causing the output oil pressure fluctuation of the lifting oil pump; the control port of the hydraulic control valve is connected to the second control port through a pipeline, and the position of its own valve core is adjusted by the pressure of the second control port, and the opening of the first unloading valve and the second unloading valve is adjusted to adjust the outlet oil pressure of the lifting oil pump and keep the pressure difference before and after the main lifting valve stable.

[0019] Furthermore, the magnitude of the output oil pressure of the first pilot proportional valve and the second pilot proportional valve is controlled by the magnitude of the output current of the vehicle controller; the oil return ports of the first pilot proportional valve and the second pilot proportional valve are connected to the oil discharge port through a pipeline.

[0020] Furthermore, it also includes: a relief valve, a throttle valve, a first unloading valve, and a second unloading valve. The oil inlet of the relief valve is connected to the oil outlet of the hydraulic control valve through a pipeline, and the oil outlet is connected to the oil discharge port through a pipeline. The relief valve is used to limit the maximum oil pressure value output by the lifting oil pump. If the pressure value is exceeded, the oil discharge port is connected to send the hydraulic oil into the hydraulic oil tank; the oil inlet of the throttle valve is connected to the working oil return port of the lifting valve group through a pipeline, and the oil outlet of the throttle valve is connected to the hydraulic oil tank through a pipeline; the oil inlet of the first unloading valve is connected to the first oil outlet of the lifting valve group through a pipeline, and the oil outlet of the first unloading valve is connected to the main oil return port through a pipeline; the oil inlet of the second unloading valve is connected to the second oil outlet of the lifting valve group through a pipeline, and the oil outlet of the second unloading valve is connected to the main oil return port through a pipeline.

[0021] Furthermore, the first main lift valve oil outlet is provided with a first detection port, the second main lift valve oil outlet is provided with a second detection port, and the oil inlet of the hydraulic control valve is respectively connected to the first detection port and the second detection port of the main lift valve through pipelines.

[0022] Furthermore, the lifting oil pump and the control oil pump adopt gear pumps, the oil suction port of the lifting oil pump is provided with a first oil suction filter, and the oil suction port of the control oil pump is provided with a second oil suction filter, the first oil suction filter and the second oil suction filter are connected to the hydraulic oil tank through pipelines; a first damping hole and a second damping hole are provided on the pipeline between the first oil outlet and the main oil return port, and the first damping hole and the second damping hole are used to release the residual pressure generated by the small chambers of the left lifting oil cylinder and the right lifting oil cylinder.

[0023] The method for using the electro-hydraulic proportional lifting control device for a mining dump truck includes:

[0024] When the vehicle is in operation, the engine drives the lifting oil pump and the control oil pump to work. When the vehicle controller detects that the car body has completely fallen onto the frame, the vehicle controller outputs an electrical signal to energize the electromagnet of the cut-off valve. At this time, the first unloading valve and the second unloading valve are energized and connected, the oil inlet is connected to the main oil return port, and the oil output by the lifting oil pump directly returns to the hydraulic oil tank. The pressure oil output by the control oil pump is adjusted to the set value after passing through the pressure reducing valve, and the pressure oil is output to the oil inlets of the first pilot proportional valve and the second pilot proportional valve respectively. The proportional electromagnets of the first pilot proportional valve and the second pilot proportional valve wait for the output electrical signal of the vehicle controller, the first pilot proportional valve and the second pilot proportional valve are disconnected, and the main lifting valve is in a waiting state.

[0025] When the lifting button is operated, the vehicle controller sends an electrical signal to the first pilot proportional valve, and the cut-off valve is disconnected at the same time. The pilot oil output by the first pilot proportional valve acts on the first control port of the main lifting valve, driving the valve core of the main lifting valve to work in the lifting position; the pressure oil output by the lifting oil pump passes through the main lifting valve, and is output from the second oil outlet of the lifting valve group to enter the large chamber of the left lifting cylinder and the right lifting cylinder, so that the car body can be lifted; at the same time, the oil pressure value of the second oil outlet is also fed back to the control port of the first unloading valve and the second unloading valve through the oil outlet of the hydraulic control valve through the third damping hole, controlling the opening of the first unloading valve and the second unloading valve, so that the pressure difference between the oil inlet and the oil outlet of the main lifting valve is kept stable;

[0026] When the descending button is operated, the vehicle controller sends an electrical signal to the second pilot proportional valve and stops sending the electrical signal to the cut-off valve. The pilot oil output by the second pilot proportional valve acts on the second control port of the main lifting valve and the control port of the hydraulic control valve to drive the valve core of the main lifting valve to work in the descending position; the pressure oil output by the lifting oil pump passes through the main lifting valve and enters the small chambers of the left lifting cylinder and the right lifting cylinder from the first oil outlet of the lifting valve group, and the car body is lowered; at the same time, the oil pressure at the first oil outlet of the lifting valve group is fed back to the control ports of the first unloading valve and the second unloading valve through the control position of the hydraulic control valve via the third damping hole, so that the pressure difference between the oil inlet and outlet of the main lifting valve remains stable.

[0027] Preferably, when the lifting button is released, the vehicle controller stops sending an electrical signal to the first pilot proportional valve, and sends an electrical signal to the cut-off valve at the same time, the first pilot proportional valve stops outputting pilot oil to the first control port of the main lifting valve, and the return spring drives the valve core of the main lifting valve to work in the holding position, and the main lifting valve cuts off the pressure oil output by the lifting oil pump, and at the same time cuts off the oil at the second oil outlet of the lifting valve group, so that the carriage can achieve the holding action; the solenoid of the cut-off valve is energized, the control ports of the first unloading valve and the second unloading valve are connected to the return oil pipe, the first unloading valve and the second unloading valve are connected, and the oil output by the lifting oil pump directly returns to the hydraulic oil tank.

[0028] Preferably, the floating button is operated, the vehicle controller sends an electrical signal to the second pilot proportional valve, and at the same time sends an electrical signal to the cut-off valve, the pilot oil output by the second pilot proportional valve acts on the second control port of the main lifting valve and the control port of the hydraulic control valve, driving the valve core of the main lifting valve to work in the floating position; the pressure oil output by the lifting oil pump is cut off by the main lifting valve, and the oil at the first oil outlet and the second oil outlet of the lifting valve group enters the hydraulic oil tank through the return oil port of the main lifting valve, the oil in the large chamber and the small chamber of the left lifting cylinder and the right lifting cylinder are connected to the hydraulic oil tank, and the car is lowered under the action of its own weight; at this time, the electromagnet of the cut-off valve is energized, the control ports of the first unloading valve and the second unloading valve are connected to the main return oil port, and the oil output by the lifting oil pump returns to the hydraulic oil tank.

[0029] The technical effects of the present invention include:

[0030] The present invention designs the operation mode of the main lifting valve to be controlled by a pilot proportional valve, which effectively reduces the impact force of the lifting action on the lifting cylinder and the frame. At the same time, the outlet pressure setting value of the lifting oil pump changes with the load pressure, so that the pressure difference before and after the main lifting valve is maintained at a constant value, which effectively reduces the impact force of the lifting action on the lifting cylinder and the frame, and improves the stability of the lifting speed of the car body.

[0031] The present invention adopts the operation mode of controlling the main lifting valve by a pilot proportional valve, which effectively reduces the energy loss of the lifting system and improves the running economy of the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a structural principle diagram of the electro-hydraulic proportional lifting control device for a mining dump truck in the present invention.

[0033] Among them: 1. Hydraulic oil tank, 2. First oil suction filter, 3. Lifting oil pump, 4. Integrated valve group, 5. Left lifting cylinder, 6. Right lifting cylinder, 7. Second oil suction filter, 8. Control oil pump, 9. Pressure reducing valve, 10. First pilot proportional valve, 11. Second pilot proportional valve, 12. Main lifting valve, 13. Hydraulic control valve, 14. Overflow valve, 15. Cut-off valve, 16. First unloading valve, 17. Second unloading valve, 18. Throttle valve, 19. First load relief valve, 20. Second load relief valve, 21. First damping hole, 22. Second damping hole, 23. Third damping hole, 24. Load control valve. DETAILED DESCRIPTION

[0034] The following description fully illustrates the specific implementation scheme of the present invention so that those skilled in the art can practice and reproduce it. The present invention is further explained below in conjunction with the specific implementation scheme.

[0035] like Figure 1 , which is a structural principle diagram of the electro-hydraulic proportional lifting control device for a mining dump truck in the present invention.

[0036] The electro-hydraulic proportional lifting control device for a mining dump truck comprises: a hydraulic oil tank 1, a first oil suction filter 2, a lifting oil pump 3, a lifting valve group 4, a left lifting oil cylinder 5, a right lifting oil cylinder 6, a second oil suction filter 7, and a control oil pump 8.

[0037] The hydraulic oil tank 1 plays the role of storing oil in the device.

[0038] The lifting oil pump 3 is a gear pump, which is installed at the power output end of the engine, takes power from the power output end of the engine, and provides lifting oil pressure for the entire lifting control device. The oil suction port of the lifting oil pump 3 is connected to the hydraulic oil tank 1 through a pipeline, and the oil outlet of the lifting oil pump 3 is connected to the power oil inlet (P port) of the lifting valve group 4 through a pipeline.

[0039] The oil suction port of the lift oil pump 3 is provided with a first oil suction filter 2 to prevent larger pollutants from being sucked into the lift oil pump 3 and causing early damage to the lift oil pump 3 .

[0040] The lifting valve group 4 is used to transmit the lifting power of the lifting oil pump 3 to the left lifting oil cylinder 5 and the right lifting oil cylinder 6. The first oil outlet (port A) of the lifting valve group 4 is connected to the lowering ports of the left lifting oil cylinder 5 and the right lifting oil cylinder 6 through a pipeline, and the second oil outlet (port B) of the lifting valve group 4 is connected to the lifting ports of the left lifting oil cylinder 5 and the right lifting oil cylinder 6 through a pipeline. The main oil return port (port T) and the oil discharge port (port DR) of the lifting valve group 4 are connected to the hydraulic oil tank 1 through pipelines to return the oil in the lifting valve group 4 to the hydraulic oil tank 1.

[0041] The lifting valve group 4 adopts an integrated valve group, which includes: a pressure reducing valve 9, a first pilot proportional valve 10, a second pilot proportional valve 11, a main lifting valve 12, a hydraulic control valve 13, a relief valve 14, a cut-off valve 15, a first unloading valve 16, a second unloading valve 17, a first load relief valve 19, a second load relief valve 20, a first damping hole 21, a second damping hole 22, a third damping hole 23, and a load control valve 24.

[0042] The left lifting cylinder 5 and the right lifting cylinder 6 are hydraulic cylinders, and the two ends of the cylinder barrel of the hydraulic cylinder are respectively provided with a front cover and a rear cover, the front cover is provided with a cylinder hole and a descending port, and the rear cover is provided with a lifting port. The hydraulic piston is located in the inner cavity of the cylinder barrel, and the hydraulic piston divides the inner cavity into a large cavity and a small cavity. The front cover is located on the side of the small cavity, and the rear cover is located on the side of the large cavity; the bottom of the hydraulic rod is connected to the hydraulic piston, and the top of the hydraulic rod extends from the cylinder hole. The descending port is connected to the first oil outlet (port A) through a pipeline, and the lifting port is connected to the second oil outlet (port B) through a pipeline.

[0043] The pressure reducing valve 9 is used to reduce the control oil pressure to the set value. The oil inlet is connected to the pilot oil inlet (PP port) of the lifting valve group 4 through a pipeline, and the oil outlet is connected to the oil inlet of the first pilot proportional valve 10 and the second pilot proportional valve 11 respectively. The overflow port is connected to the oil discharge port (DR port) through a pipeline to provide power oil pressure for the first pilot proportional valve 10 and the second pilot proportional valve 11. The pressure reducing valve 9 is a pressure reducing valve with an overflow function, which reduces the oil pressure output by the control oil pump 8 to 30 bar (set value).

[0044] The oil outlet of the first pilot proportional valve 10 is connected to the first control port (port pa) of the main lift valve 12 through a pipeline; the oil outlet of the second pilot proportional valve 11 is connected to the second control port (port pb) of the main lift valve 12 through a pipeline; the output pressure command of the vehicle controller is received, and the oil pressure is output according to the output pressure command. The output oil pressure of the first pilot proportional valve 10 and the second pilot proportional valve 11 is controlled by the output current of the vehicle controller. The return oil ports of the first pilot proportional valve 10 and the second pilot proportional valve 11 are connected to the oil drain port (port DR) through a pipeline.

[0045] The oil inlet of the main lift valve 12 is connected to the oil inlet (P port) through a pipeline, the first main lift valve oil outlet of the main lift valve 12 is connected to the first oil outlet (A port) through a pipeline, and the second main lift valve oil outlet of the main lift valve 12 is connected to the second oil outlet (B port) through a pipeline. The main lift valve 12 is used to form pressure oil at the first oil outlet (A port) and the second oil outlet (B port), and to form a pressure difference between the first oil outlet (A port) and the second oil outlet (B port). The first main lift valve oil outlet is provided with a first detection port LS1, and the second main lift valve oil outlet is provided with a second detection port LS2. The oil return port of the main lift valve 12 is connected to the main oil return port (T port) through a pipeline.

[0046] The main lifting valve 12 is the main component that controls the action of the lifting cylinders (left lifting cylinder 5 and right lifting cylinder 6), and can control the four actions of lifting, lowering, holding and floating of the car body. The load control valve 24 is integrated inside the valve core of the main lifting valve 12. The load control valve 24 can prevent the backward pulling force generated when the car body is lifted to a high position, which may cause damage to the lifting cylinder.

[0047] The hydraulic control valve 13 is used to maintain the pressure difference between the oil inlet of the main lift valve 12 and the oil outlet of the first main lift valve and the oil outlet of the second main lift valve, so that the pressure difference before and after the main lift valve 12 is maintained at a constant value. The oil inlet of the hydraulic control valve 13 is connected to the first detection port LS1 and the second detection port LS2 of the main lift valve 12 through pipelines, respectively, and the oil outlet of the hydraulic control valve 13 is connected to the oil inlet of the overflow valve 14 and the control ports of the first unloading valve 16 and the second unloading valve 17 through pipelines; the function of the hydraulic control valve 13 is to transfer the load pressure of the lifting cylinder (left lifting cylinder 5 and right lifting cylinder 6) to the outlet of the lifting oil pump 3 when the car body is lifted, control the opening of the first unloading valve 16 and the second unloading valve 17, so that the pressure difference before and after the main lift valve 12 is maintained at a constant value. The control port of the hydraulic control valve 13 is connected to the second control port (pb port) through a pipeline, and the position of its own valve core is adjusted by the pressure of the second control port (pb port) of the main lift valve 12, and the opening of the first unloading valve 16 and the second unloading valve 17 is adjusted to adjust the outlet oil pressure of the lift oil pump 3 and keep the pressure difference before and after the main lift valve 12 stable. The oil outlet of the hydraulic control valve 13 is connected to the main load pressure feedback signal oil outlet (LS port) of the lift valve group 4 through the third damping hole 23. The oil outlet of the hydraulic control valve 13 is connected to the third damping hole 23 through a pipeline, and the third damping hole 23 is connected to the oil inlet of the overflow valve 14 and the control ports of the first unloading valve 16 and the second unloading valve 17 through a pipeline. The third damping hole 23 is set to prevent the load pressure fluctuation fed back by the hydraulic control valve 13 from causing the output oil pressure fluctuation of the lift oil pump 3.

[0048] The oil outlet of the relief valve 14 is connected to the oil drain port (DR port) through a pipeline. Its function is to limit the maximum oil pressure value output by the lifting oil pump 3 to not exceed the pressure setting value of the relief valve 14. If it exceeds the pressure setting value, the oil drain port (DR port) is connected to send the hydraulic oil into the hydraulic oil tank 1.

[0049] The shut-off valve 15 is a solenoid valve, the oil inlet of which is respectively connected to the control ports of the first unloading valve 16 and the second unloading valve 17, the oil inlet of the overflow valve 14 and the third damping hole 23 through pipelines, and the oil outlet is connected to the oil drain port (DR port) through a pipeline; when the car body is not lifted or lowered, the electromagnet of the shut-off valve 15 is energized, the oil return ports of the first pilot proportional valve 10 and the second pilot proportional valve 11 are connected to the oil drain port (DR port), and the oil of the control oil pump 8 returns to the hydraulic oil tank 1 through the oil drain port (DR port), so that the oil outlet pressure of the control oil pump 8 is close to zero, thereby reducing the energy loss of the lifting device.

[0050] The first unloading valve 16 and the second unloading valve 17 are solenoid valves, and the oil outlets of the first unloading valve 16 and the second unloading valve 17 are respectively connected to the main oil return port (T port) through pipelines, and the oil inlets of the first unloading valve 16 and the second unloading valve 17 are respectively connected to the oil outlet of the lifting oil pump 3. When the car is not lifting or lowering, the first unloading valve 16 and the second unloading valve 17 are electrically connected, and the oil output by the lifting oil pump 3 directly returns to the hydraulic oil tank 1 through the main oil return port (T port).

[0051] The oil inlet of the throttle valve 18 is connected to the working oil return port (BL port) of the lifting valve group 4 through a pipeline, and the oil outlet of the throttle valve 18 is connected to the hydraulic oil tank 1 through a pipeline; the lifting valve group 4 is connected to the hydraulic oil tank 1 through the throttle valve 18, and the throttle valve 18 is provided to enable the oil in the lifting cylinders (left lifting cylinder 5 and right lifting cylinder 6) to return to the hydraulic oil tank 1 by the dead weight of the carriage in an emergency situation.

[0052] The oil inlet of the first unloading valve 19 is connected to the first oil outlet (port A) of the lifting valve group 4 through a pipeline, and the oil outlet of the first unloading valve 19 is connected to the main oil return port (port T) through a pipeline; the oil inlet of the second unloading valve 20 is connected to the second oil outlet (port B) of the lifting valve group 4 through a pipeline, and the oil outlet of the second unloading valve 20 is connected to the main oil return port (port T) through a pipeline; the function of the first unloading valve 19 and the second unloading valve 20 is to prevent the lifting cylinder from generating a large impact pressure during the lifting and lowering of the car body.

[0053] The first damping hole 21 and the second damping hole 22 are arranged on the pipeline between the first oil outlet (port A) and the main oil return port (port T), and the first damping hole 21 and the second damping hole 22 are used to release the residual pressure generated by the small chamber of the lifting cylinder (the left lifting cylinder 5 and the right lifting cylinder 6).

[0054] The detection port MA, detection port MB, detection port Ma, detection port Mb, main detection port LS, detection port MP, first detection port LS1, and second detection port LS2 of the integrated valve group 4 are all pressure detection ports, which are convenient for debugging or troubleshooting. The detection port MA is connected to the first oil outlet (port A) through a pipeline, the detection port MB is connected to the second oil outlet (port B) through a pipeline, the detection port Ma is connected to the first control port (port pa) of the main lift valve 12 through a pipeline, the detection port Mb is connected to the second control port (port pb) of the main lift valve 12 through a pipeline, the detection port MP is connected to the oil inlet (port P) of the lift valve group 4 through a pipeline, and the main detection port LS is connected to the oil inlet of the overflow valve 14 through a pipeline.

[0055] The oil suction port of the control oil pump 8 is connected to the hydraulic oil tank 1 through a pipeline, and the oil outlet is connected to the pilot oil inlet (PP port) of the lift valve group 4 through a pipeline, so as to form the control oil pressure and transmit the control oil pressure to the lift valve group 4. The control oil pump 8 adopts a small-displacement gear pump, and the oil suction port of the control oil pump 8 is provided with a second oil suction filter 7, which is connected to the hydraulic oil tank 1 through a pipeline.

[0056] The use method of the electro-hydraulic proportional lifting control device for mining dump trucks includes the following working modes:

[0057] (1) The vehicle is in the off state. The engine is not running. The lifting oil pump 3 and the control oil pump 8 have no pressure oil output, and the entire mining dump truck electro-hydraulic proportional lifting control device does not work.

[0058] (2) The vehicle is in operation. The engine drives the lifting oil pump 3 and the control oil pump 8 to work. The vehicle controller detects that the car body has completely fallen onto the frame. The vehicle controller outputs an electrical signal to energize the electromagnet of the cut-off valve 15. At this time, the first unloading valve 16 and the second unloading valve 17 are energized and connected. The oil inlet is connected to the main oil return port (T port). The oil output by the lifting oil pump 3 directly returns to the hydraulic oil tank 1. The control oil pump 8 outputs the pressure oil through the pressure reducing valve 9. The pressure is adjusted to 30 bar and is output to the oil inlets of the first pilot proportional valve 10 and the second pilot proportional valve 11 respectively. The proportional electromagnets of the first pilot proportional valve 10 and the second pilot proportional valve 11 do not receive the output electrical signal of the vehicle controller. The first pilot proportional valve 10 and the second pilot proportional valve 11 are disconnected. The valve core of the main lifting valve 12 does not move. The entire system is in a standby state.

[0059] (3) The driver presses the lift button in the cab. At this time, the vehicle controller sends an electrical signal to the first pilot proportional valve 10 and sends an electrical signal to the cut-off valve 15. The cut-off valve 15 is disconnected, and the first pilot proportional valve 10 outputs a 28 bar pilot oil to act on the first control port (pa port) of the main lift valve 12, driving the valve core of the main lift valve 12 to work in the lift position; the pressure oil output by the lift oil pump 3 passes through the main lift valve 12 and is output from the second oil outlet (B port) of the lift valve group 4 to enter the large chamber of the left lift cylinder 5 and the right lift cylinder 6, so that the car body is lifted; at the same time, the oil pressure value of the second oil outlet (B port) is also fed back to the control ports of the first unloading valve 16 and the second unloading valve 17 through the oil outlet of the hydraulic control valve 13 and the third damping hole 23, so as to control the opening of the first unloading valve 16 and the second unloading valve 17, so that the pressure difference between the oil inlet and the oil outlet of the main lift valve 12 is kept stable.

[0060] (4) The driver releases the lifting button in the cab. At this time, the vehicle controller stops sending an electrical signal to the first pilot proportional valve 10 and sends an electrical signal to the cut-off valve 15. The first pilot proportional valve 10 stops outputting pilot oil to the first control port (pa port) of the main lifting valve 12. The return spring drives the valve core of the main lifting valve 12 to work in the holding position. The main lifting valve 12 cuts off the pressure oil output by the lifting oil pump 3 and also cuts off the oil at the second oil outlet (B port) of the lifting valve group 4, so that the car can be held. At this time, the electromagnet of the cut-off valve 15 is energized. At this time, the control ports of the first unloading valve 16 and the second unloading valve 17 are connected to the return oil pipe. The first unloading valve 16 and the second unloading valve 17 are connected, and the oil output by the lifting oil pump 3 directly returns to the hydraulic oil tank 1.

[0061] (5) The driver presses the descending button in the cab. At this time, the vehicle controller sends an electrical signal to the second pilot proportional valve 11 and stops sending the electrical signal to the cut-off valve 15. The second pilot proportional valve 11 outputs a 28 bar pilot oil to act on the pb port of the main lift valve 12 and the control port of the hydraulic control valve 13, driving the valve core of the main lift valve 12 to work in the descending position; the pressure oil output by the lift oil pump 3 passes through the main lift valve 12 and is output from the first oil outlet (port A) of the lift valve group 4 to the small chambers of the left lift cylinder 5 and the right lift cylinder 6, and the car body is lowered; at the same time, the oil pressure value of the first oil outlet (port A) of the lift valve group 4 is also fed back to the control ports of the first unloading valve 16 and the second unloading valve 17 through the control position of the hydraulic control valve 13 and the third damping hole 23, so that the pressure difference between the oil inlet and the oil outlet of the main lift valve 12 remains stable.

[0062] (6) The driver operates the floating button in the cab. At this time, the vehicle controller sends an electrical signal to the second pilot proportional valve 11 and sends an electrical signal to the cut-off valve 15. The second pilot proportional valve 11 outputs a 13 bar pilot oil to act on the second control port (pb port) of the main lift valve 12 and the control port of the hydraulic control valve 13, driving the valve core of the main lift valve 12 to work in the floating position; the pressure oil output by the lift pump 3 is cut off by the main lift valve 12, and the oil from the first oil outlet (port A) and the second oil outlet (port B) of the lift valve group 4 enters the hydraulic oil tank 1 through the return oil port of the main lift valve 12. The oil in the large chamber and the small chamber of the left lift cylinder 5 and the right lift cylinder 6 are connected to the hydraulic oil tank 1, and the car body slowly descends under the action of its own weight; at this time, the electromagnet of the cut-off valve 15 is energized, and the control ports of the first unloading valve 16 and the second unloading valve 17 are connected to the main return oil port (port T), and the oil output by the lift pump 3 returns to the hydraulic oil tank 1.

[0063] The terms used in the present invention are illustrative and exemplary, rather than restrictive. Since the present invention can be implemented in various forms without departing from the spirit or essence of the technical solution, it should be understood that the above embodiments are not limited to any of the aforementioned details, but should be widely interpreted within the spirit and scope defined by the attached claims, so all changes and modifications falling within the scope of the claims or their equivalents should be covered by the attached claims.

Claims

1. An electro-hydraulic proportional lifting control device for a mining dump truck, characterized in that: include: A hydraulic oil tank, used to store oil; The lifting oil pump takes power from the power output end of the engine and is used to provide lifting oil pressure. Its oil suction port is connected to the hydraulic oil tank through a pipeline, and its oil outlet is connected to the power oil inlet of the lifting valve group through a pipeline; The lifting valve group is used to transmit the lifting power of the lifting oil pump to the left lifting cylinder and the right lifting cylinder. The first oil outlet is connected to the lowering port of the left lifting cylinder and the right lifting cylinder through pipelines, and the second oil outlet is connected to the lifting port of the left lifting cylinder and the right lifting cylinder through pipelines. The main oil return port and the oil discharge port are connected to the hydraulic oil tank through pipelines. The lifting valve group adopts an integrated valve group, including: a pressure reducing valve, a first pilot proportional valve, a second pilot proportional valve, a main lifting valve, a hydraulic control valve, and a relief valve. A pressure reducing valve, used to reduce the control oil pressure to a set value and deliver it to the first pilot proportional valve and the second pilot proportional valve, wherein the oil inlet is connected to the pilot oil inlet of the lift valve group through a pipeline, the oil outlet is connected to the oil inlet of the first pilot proportional valve and the second pilot proportional valve respectively, and the overflow port is connected to the oil discharge port through a pipeline; The first pilot proportional valve and the second pilot proportional valve receive the output pressure command of the vehicle controller, and output or cut off the pressure oil according to the output pressure command. The oil outlet of the first pilot proportional valve is connected to the first control port of the main lift valve through a pipeline, and the oil outlet of the second pilot proportional valve is connected to the second control port of the main lift valve through a pipeline. The main lift valve is used to form pressure oil at the first oil outlet and the second oil outlet, and to form a pressure difference between the first oil outlet and the second oil outlet; its oil inlet is connected to the oil inlet of the main lift valve through a pipeline, the first main lift valve oil outlet is connected to the first oil outlet through a pipeline, the second main lift valve oil outlet is connected to the second oil outlet through a pipeline, and the oil return port is connected to the main oil return port through a pipeline; A hydraulically controlled valve, used to maintain a constant pressure difference between the oil inlet of the main lift valve and the oil outlet of the first main lift valve and the oil outlet of the second main lift valve, wherein the oil inlet is connected to the first detection port and the second detection port of the main lift valve through pipelines, and the oil outlet is connected to the oil inlet of the cut-off valve through a pipeline; The cut-off valve receives the output pressure command of the vehicle controller, outputs or cuts off the pressure oil according to the output pressure command, and its oil inlet is connected to the control ports of the first unloading valve and the second unloading valve through pipelines, and its oil outlet is connected to the oil drain port through pipelines; The first unloading valve and the second unloading valve are solenoid valves, whose oil outlets are connected to the main oil return port through pipelines, and whose oil inlets are connected to the oil outlet of the lifting oil pump through pipelines, and are used to connect or disconnect the connection between the lifting oil pump and the hydraulic oil tank; The control oil pump takes power from the power output end of the engine to form the control oil pressure and transmit the control oil pressure to the pilot oil inlet of the lifting valve group. Its oil suction port is connected to the hydraulic oil tank through a pipeline, and its oil outlet is connected to the oil inlet of the lifting valve group through a pipeline.

2. The electro-hydraulic proportional lifting control device for a mining dump truck according to claim 1, characterized in that: The oil outlet of the hydraulic control valve is connected to the oil inlet of the overflow valve and the control ports of the first unloading valve and the second unloading valve through pipelines; when the car body is lifted, the load pressure of the left lifting cylinder and the right lifting cylinder is transmitted to the outlet of the lifting oil pump to control the opening of the first unloading valve and the second unloading valve to keep the pressure difference before and after the main lifting valve constant; the control port of the hydraulic control valve is connected to the second control port through a pipeline, and the valve core position is adjusted by the pressure of the second control port to keep the pressure difference before and after the main lifting valve stable.

3. The electro-hydraulic proportional lifting control device for a mining dump truck according to claim 1, characterized in that: The oil outlet of the hydraulic control valve is connected to the third damping hole through a pipeline, and the third damping hole is connected to the control ports of the first unloading valve and the second unloading valve through a pipeline. The third damping hole is used to prevent the load pressure fluctuation fed back by the hydraulic control valve from causing the output oil pressure fluctuation of the lifting oil pump; the control port of the hydraulic control valve is connected to the second control port through a pipeline, and the position of its own valve core is adjusted by the pressure of the second control port, and the opening of the first unloading valve and the second unloading valve is adjusted to adjust the outlet oil pressure of the lifting oil pump and keep the pressure difference before and after the main lifting valve stable.

4. The electro-hydraulic proportional lifting control device for a mining dump truck according to claim 1, characterized in that: The magnitude of the output oil pressure of the first pilot proportional valve and the second pilot proportional valve is controlled by the magnitude of the output current of the vehicle controller; the return oil ports of the first pilot proportional valve and the second pilot proportional valve are connected to the oil discharge port through pipelines.

5. The electro-hydraulic proportional lifting control device for a mining dump truck according to claim 1, characterized in that: Also includes: A relief valve, a throttle valve, a first unloading valve and a second unloading valve, the oil inlet of the relief valve is connected to the oil outlet of the hydraulic control valve through a pipeline, and the oil outlet is connected to the oil discharge port through a pipeline. The relief valve is used to limit the maximum oil pressure value output by the lifting oil pump. If the pressure value is exceeded, the oil discharge port is connected to send the hydraulic oil into the hydraulic oil tank; the oil inlet of the throttle valve is connected to the working oil return port of the lifting valve group through a pipeline, and the oil outlet of the throttle valve is connected to the hydraulic oil tank through a pipeline; the oil inlet of the first unloading valve is connected to the first oil outlet of the lifting valve group through a pipeline, and the oil outlet of the first unloading valve is connected to the main oil return port through a pipeline; the oil inlet of the second unloading valve is connected to the second oil outlet of the lifting valve group through a pipeline, and the oil outlet of the second unloading valve is connected to the main oil return port through a pipeline.

6. The electro-hydraulic proportional lifting control device for a mining dump truck according to claim 1, characterized in that: The first main lift valve oil outlet is provided with a first detection port, the second main lift valve oil outlet is provided with a second detection port, and the oil inlet of the hydraulic control valve is connected to the first detection port and the second detection port of the main lift valve through pipelines.

7. The electro-hydraulic proportional lifting control device for a mining dump truck according to claim 1, characterized in that: The lifting oil pump and the control oil pump adopt gear pumps. The oil suction port of the lifting oil pump is provided with a first oil suction filter, and the oil suction port of the control oil pump is provided with a second oil suction filter. The first oil suction filter and the second oil suction filter are connected to the hydraulic oil tank through pipelines; a first damping hole and a second damping hole are provided on the pipeline between the first oil outlet and the main oil return port. The first damping hole and the second damping hole are used to release the residual pressure generated by the small chambers of the left lifting oil cylinder and the right lifting oil cylinder.

8. The method for using the electro-hydraulic proportional lifting control device for a mining dump truck according to any one of claims 1 to 7, characterized in that: include: When the vehicle is in operation, the engine drives the lifting oil pump and the control oil pump to work. When the vehicle controller detects that the car body has completely fallen onto the frame, the vehicle controller outputs an electrical signal to energize the electromagnet of the cut-off valve. At this time, the first unloading valve and the second unloading valve are energized and connected, the oil inlet is connected to the main oil return port, and the oil output by the lifting oil pump directly returns to the hydraulic oil tank. The pressure oil output by the control oil pump is adjusted to the set value after passing through the pressure reducing valve, and the pressure oil is output to the oil inlets of the first pilot proportional valve and the second pilot proportional valve respectively. The proportional electromagnets of the first pilot proportional valve and the second pilot proportional valve wait for the output electrical signal of the vehicle controller, the first pilot proportional valve and the second pilot proportional valve are disconnected, and the main lifting valve is in a waiting state. When the lifting button is operated, the vehicle controller sends an electrical signal to the first pilot proportional valve, and the cut-off valve is disconnected at the same time. The pilot oil output by the first pilot proportional valve acts on the first control port of the main lifting valve, driving the valve core of the main lifting valve to work in the lifting position; the pressure oil output by the lifting oil pump passes through the main lifting valve, and is output from the second oil outlet of the lifting valve group to enter the large chamber of the left lifting cylinder and the right lifting cylinder, so that the car body can be lifted; at the same time, the oil pressure value of the second oil outlet is also fed back to the control port of the first unloading valve and the second unloading valve through the oil outlet of the hydraulic control valve through the third damping hole, controlling the opening of the first unloading valve and the second unloading valve, so that the pressure difference between the oil inlet and the oil outlet of the main lifting valve is kept stable; When the descending button is operated, the vehicle controller sends an electrical signal to the second pilot proportional valve and stops sending the electrical signal to the cut-off valve. The pilot oil output by the second pilot proportional valve acts on the second control port of the main lifting valve and the control port of the hydraulic control valve to drive the valve core of the main lifting valve to work in the descending position; the pressure oil output by the lifting oil pump passes through the main lifting valve and enters the small chambers of the left lifting cylinder and the right lifting cylinder from the first oil outlet of the lifting valve group, and the car body is lowered; at the same time, the oil pressure at the first oil outlet of the lifting valve group is fed back to the control ports of the first unloading valve and the second unloading valve through the control position of the hydraulic control valve via the third damping hole, so that the pressure difference between the oil inlet and outlet of the main lifting valve remains stable.

9. The method for using the electro-hydraulic proportional lifting control device for a mining dump truck according to claim 8, characterized in that: Release the lifting button, the vehicle controller stops sending electrical signals to the first pilot proportional valve, and sends electrical signals to the cut-off valve at the same time. The first pilot proportional valve stops outputting pilot oil to the first control port of the main lifting valve, and the return spring drives the valve core of the main lifting valve to work in the holding position. The main lifting valve cuts off the pressure oil output by the lifting oil pump, and cuts off the oil at the second oil outlet of the lifting valve group at the same time, so that the carriage can be held; the solenoid of the cut-off valve is energized, the control ports of the first unloading valve and the second unloading valve are connected to the return oil pipe, the first unloading valve and the second unloading valve are connected, and the oil output by the lifting oil pump directly returns to the hydraulic oil tank.

10. The method for using the electro-hydraulic proportional lifting control device for a mining dump truck according to claim 8, characterized in that: Operate the floating button, the vehicle controller sends an electrical signal to the second pilot proportional valve, and sends an electrical signal to the cut-off valve at the same time. The pilot oil output by the second pilot proportional valve acts on the second control port of the main lifting valve and the control port of the hydraulic control valve, driving the valve core of the main lifting valve to work in the floating position; the pressure oil output by the lifting oil pump is cut off by the main lifting valve, and the oil at the first oil outlet and the second oil outlet of the lifting valve group enters the hydraulic oil tank through the return oil port of the main lifting valve, and the oil in the large chamber and the small chamber of the left lifting cylinder and the right lifting cylinder are connected to the hydraulic oil tank, and the car is lowered under the action of its own weight; at this time, the electromagnet of the cut-off valve is energized, the control ports of the first unloading valve and the second unloading valve are connected to the main return oil port, and the oil output by the lifting oil pump returns to the hydraulic oil tank.

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