Mine dump truck electro-hydraulic proportional lifting control device and using method

Abstract

The application discloses a mine self-dumper electro-hydraulic proportional lifting control device, comprising: 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 application discloses a use method of the mine self-dumper electro-hydraulic proportional lifting control device. The application adopts a pilot proportional valve control for the main lifting valve operation mode, effectively reduces the impact force of the lifting action on the lifting oil cylinder and the frame, changes the lifting oil pump outlet pressure setting value with the load pressure, keeps a constant value for the pressure difference before and after the main lifting valve, improves the stability of the carriage lifting speed, effectively reduces the energy loss of the lifting system and improves the operation economy of the vehicle.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of mine dump trucks, and particularly relates to a mine dump truck electro-hydraulic proportional lifting control device and a use method. BACKGROUND

[0002] The mine dump truck belongs to off-highway dump trucks, and is mainly used for transporting large open-pit mine ores and mine materials. The mine dump truck mainly comprises a frame, an engine, a transmission case, a rear axle, a cab assembly, a lifting cylinder, a lifting control device and the like. The lifting control device is an important component of the mine dump truck, and particularly has a crucial influence on the working reliability and safety of the mine dump truck.

[0003] At present, the lifting control device of the mine dump truck is generally composed of a main lifting valve, a lifting pilot valve, a lifting handle and hydraulic pipelines. The oil from a 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 lifting, lowering, maintaining and floating of the carriage of the mine dump truck. However, the operation mode has a large impact on the lifting cylinder and the frame, and the driver's operation is not flexible. In addition, the lifting system has a large energy loss, a serious system heating, and a large number of hydraulic pipelines, which has a certain safety risk. SUMMARY

[0004] In view of the deficiencies in the prior art, the present application provides a mine dump truck electro-hydraulic proportional lifting control device and a use method. The main lifting valve operation mode is controlled by a pilot proportional valve, which effectively reduces the impact force of the lifting operation on the lifting cylinder and the frame. Meanwhile, the lifting oil pump outlet pressure setting value is changed with the load pressure, so that the pressure difference before and after the main lifting valve is kept constant, the stability of the carriage lifting speed is improved, the energy loss of the lifting system is effectively reduced, and the running economy of the vehicle is improved.

[0005] To achieve the above-mentioned purpose, the technical solution used by the present application is as follows:

[0006] The mine dump truck electro-hydraulic proportional lifting control device comprises:

[0007] a hydraulic oil tank for storing oil;

[0008] a lifting oil pump connected to the power output end of the engine for providing lifting oil pressure, with the oil suction port connected to the hydraulic oil tank through a pipeline and the oil outlet connected to the power oil inlet of the lifting valve group through a pipeline;

[0009] The lifting valve group is used for transmitting the lifting power of the lifting oil pump to the left lifting oil cylinder and the right lifting oil cylinder, a first oil outlet is connected with the falling ports of the left lifting oil cylinder and the right lifting oil cylinder through pipelines, a second oil outlet is connected with the lifting ports of the left lifting oil cylinder and the right lifting oil cylinder through a pipeline, and a main oil return port and a spill port are respectively connected with the hydraulic oil tank through pipelines; the lifting valve group adopts an integrated valve group, which comprises 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, wherein

[0010] The pressure reducing valve is used for reducing the control oil pressure to a set value and transmitting the control oil pressure to the first pilot proportional valve and the second pilot proportional valve, an oil inlet is connected with the pilot oil inlet of the lifting valve group through a pipeline, and oil outlets are respectively connected with the oil inlets of the first pilot proportional valve and the second pilot proportional valve through pipelines, and a relief port is connected with the spill port through a pipeline;

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

[0012] The main lifting valve is used for forming pressure oil at the first oil outlet and the second oil outlet and forming a pressure difference between the first oil outlet and the second oil outlet; an oil inlet is connected with the oil inlet of the main lifting valve through a pipeline, the first main lifting valve oil outlet is connected with the first oil outlet through a pipeline, the second main lifting valve oil outlet is connected with the second oil outlet through a pipeline, and an oil return port is connected with the main oil return port through a pipeline;

[0013] The hydraulic control valve is used for keeping a constant pressure difference between the oil inlet of the main lifting valve and the first main lifting valve oil outlet and the second main lifting valve oil outlet, the oil inlet is respectively connected with the first detection port and the second detection port of the main lifting valve through pipelines, and the oil outlet is connected with the oil inlet of the cut-off valve through a pipeline;

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

[0015] The first unloading valve and the second unloading valve are solenoid valves, the oil outlet is connected with the main oil return port through a pipeline, and the oil inlet is connected with the oil outlet of the lifting oil pump through a pipeline, which is used for connecting or disconnecting the communication 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, is used for forming the control oil pressure, and transmits the control oil pressure to the pilot oil inlet of the lifting valve group, the oil suction port is connected with the hydraulic oil tank through a pipeline, and the oil outlet is connected with the oil inlet of the lifting valve group through a pipeline.

[0017] Further, the oil outlet of the hydraulic control valve is connected to the oil inlet of the overflow valve and the control port of the first and second unloading valves through pipelines; when the vehicle cabin is lifted, the load pressure of the left and right lifting cylinders is transmitted to the outlet of the lifting oil pump, the opening degree of the first and second unloading valves is controlled, and the pressure difference before and after the main lifting valve is kept constant; the control port of the hydraulic control valve is connected to the second control port through a pipeline, the valve core position is adjusted by the pressure of the second control port, and the pressure difference before and after the main lifting valve is kept stable.

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

[0019] Further, the output oil pressure of the first and second pilot proportional valves is controlled by the output current of the vehicle controller; the return oil ports of the first and second pilot proportional valves are connected to the oil drain port through pipelines.

[0020] Further, the overflow valve, the throttle valve, the first and second load relief valves are further included, the oil inlet of the overflow valve is connected to the oil outlet of the hydraulic control valve through a pipeline, the oil outlet is connected to the oil drain port through a pipeline, the overflow valve is used to limit the maximum oil pressure value output by the lifting oil pump, and the hydraulic oil is sent into the hydraulic oil tank when the value is exceeded; the oil inlet of the throttle valve is connected to the working return oil port of the lifting valve group through a pipeline, the oil outlet of the throttle valve is connected to the hydraulic oil tank through a pipeline; the oil inlet of the first load relief valve is connected to the first oil outlet of the lifting valve group through a pipeline, and the oil outlet of the first load relief valve is connected to the main return oil port through a pipeline; the oil inlet of the second load relief valve is connected to the second oil outlet of the lifting valve group through a pipeline, and the oil outlet of the second load relief valve is connected to the main return oil port through a pipeline.

[0021] Further, the first detection port is arranged at the oil outlet of the first main lifting valve, the second detection port is arranged at the oil outlet of the second main lifting valve, and the oil inlets of the hydraulic control valve are connected to the first and second detection ports of the main lifting valve through pipelines.

[0022] Further, the lifting oil pump and the control oil pump adopt gear pumps, the suction port of the lifting oil pump is provided with a first suction filter screen, the suction port of the control oil pump is provided with a second suction filter screen, the first suction filter screen and the second suction filter screen are connected with the hydraulic oil tank through pipelines; the first damping hole and the second damping hole are arranged 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 for releasing residual pressure generated by the small cavities of the left lifting oil cylinder and the right lifting oil cylinder.

[0023] The method for using the mine dump truck electro-hydraulic proportional lifting control device comprises the following steps:

[0024] When the vehicle is in a running state, the engine drives the lifting oil pump and the control oil pump to work, the vehicle controller detects that the vehicle compartment is completely lowered on the vehicle frame, and the vehicle controller outputs an electric signal to electrify the electromagnet of the cut-off valve; at this time, the first unloading valve and the second unloading valve are electrified and connected, the oil inlet is communicated with 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 a 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 electromagnet of the first pilot proportional valve and the second pilot proportional valve waits for the output electric 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 standby state.

[0025] When the lifting button is operated, the vehicle controller sends an electric signal to the first pilot proportional valve, and the cut-off valve is disconnected; the pilot oil output by the first pilot proportional valve acts on the first control port of the main lifting valve, drives 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 the large cavities of the left lifting oil cylinder and the right lifting oil cylinder, so that the vehicle compartment realizes the lifting action; at the same time, the oil pressure value of the second oil outlet is also fed back to the control ports of the first unloading valve and the second unloading valve through the third damping hole of the oil outlet of the hydraulic control valve, so as to control the opening degree of the first unloading valve and the second unloading valve, and keep the pressure difference between the oil inlet and the oil outlet of the main lifting valve at a stable value.

[0026] When the lowering button is operated, the vehicle controller sends an electric signal to the second pilot proportional valve, and stops sending the electric 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, drives the valve core of the main lifting valve to work in the lowering position; the pressure oil output by the lifting oil pump passes through the main lifting valve and enters the small cavities of the left lifting oil cylinder and the right lifting oil cylinder from the first oil outlet of the lifting valve group, so that the vehicle compartment realizes the lowering action; at the same time, the oil pressure of 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 third damping hole of the control port of the hydraulic control valve, so as to keep the pressure difference between the oil inlet and the oil outlet of the main lifting valve at a stable value.

[0027] Preferably, the lifting button is released, the vehicle controller stops sending electrical signals to the first pilot proportional valve, and sends electrical signals to the cut-off valve, the first pilot proportional valve stops outputting pilot oil to the first control port of the main lifting valve, the reset 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 the second oil outlet of the cut-off valve is cut off, so that the vehicle compartment realizes the holding action; the electromagnet of the cut-off valve is powered, the control ports of the first unloading valve and the second unloading valve are communicated with the oil return 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 electrical signals to the second pilot proportional valve, and sends electrical signals to the cut-off valve, the second pilot proportional valve outputs pilot oil acting on the second control port of the main lifting valve and the control port of the hydraulic control valve, and drives 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, the oil of the first oil outlet and the second oil outlet of the lifting valve group enters the hydraulic oil tank through the oil return port of the main lifting valve, the oil of the large cavity and the small cavity of the left lifting oil cylinder and the right lifting oil cylinder is communicated with the hydraulic oil tank, and the vehicle compartment realizes the descending under the action of the self-weight; At this time, the electromagnet of the cut-off valve is powered, the control ports of the first unloading valve and the second unloading valve are communicated with the main oil return port, and the oil output by the lifting oil pump returns to the hydraulic oil tank.

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

[0030] The present application designs the operation mode of the main lifting valve as pilot proportional valve control, effectively reduces the impact force of the lifting action on the lifting oil cylinder and the frame, and changes the set value of the outlet pressure of the lifting oil pump with the load pressure, so that the pressure difference before and after the main lifting valve remains a constant value, effectively reduces the impact force of the lifting action on the lifting oil cylinder and the frame, and improves the stability of the lifting speed of the vehicle compartment.

[0031] The present application adopts the operation mode of the pilot proportional valve to control the main lifting valve, effectively reduces the energy loss of the lifting system, and improves the operation economy of the vehicle. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 It is the structure principle diagram of the electric-hydraulic proportional lifting control device of the mine dump truck in the present application.

[0033] Wherein: 1. hydraulic oil tank, 2. first oil suction filter screen, 3. lifting oil pump, 4. integrated valve group, 5. left lifting oil cylinder, 6. right lifting oil cylinder, 7. second oil suction filter screen, 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 pressure relief valve, 20. second pressure 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 specific embodiments of the application to enable one of ordinary skill in the art to practice and reproduce the application, further described below in conjunction with the specific embodiments, further illustrates the present application.

[0035] As shown in the structural principle diagram of the mine dump truck electro-hydraulic proportional lifting control device in the present application. Figure 1

[0036] The mine dump truck electro-hydraulic proportional lifting control device comprises: a hydraulic oil tank 1, a first oil suction filter screen 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 screen 7, and a control oil pump 8.

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

[0038] The lifting oil pump 3 is a gear pump 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 inlet (P port) of the lifting valve group 4 through a pipeline.

[0039] The oil suction port of the lifting oil pump 3 is provided with the first oil suction filter screen 2, which is used to prevent larger contaminants from being sucked into the lifting oil pump 3 to cause early damage to the lifting 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 (A port) of the lifting valve group 4 is connected to the descending ports of the left lifting oil cylinder 5 and the right lifting oil cylinder 6 through a pipeline, and the second oil outlet (B port) 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 return port (T port) and the drain port (DR port) of the lifting valve group 4 are connected to the hydraulic oil tank 1 through a pipeline, and the oil in the lifting valve group 4 is returned to the hydraulic oil tank 1.

[0041] ​The lifting valve group 4 adopts an integrated valve group, which internally comprises: 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, an overflow valve 14, a cut-off valve 15, a first unloading valve 16, a second unloading valve 17, a first pressure relief valve 19, a second pressure 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 oil cylinder 5 and the right lifting oil cylinder 6 are hydraulic cylinders, the cylinder barrels of the hydraulic cylinders are respectively provided with front end covers and rear end covers, the front end covers are provided with cylinder holes and descending ports, the rear end covers are provided with lifting ports, hydraulic pistons are located in the inner cavities of the cylinder barrels, the hydraulic pistons divide the inner cavities into large cavities and small cavities, the front end covers are located on one side of the small cavities, and the rear end covers are located on one side of the large cavities; the bottoms of hydraulic rods are connected to the hydraulic pistons, and the tops of the hydraulic rods extend out of the cylinder holes. The descending ports are connected to the first oil outlets (A ports) through pipelines, and the lifting ports are connected to the second oil outlets (B ports) through pipelines.

[0043] The pressure reducing valve 9 is used to reduce the control oil pressure to a set value, the oil inlet is connected to the pilot oil inlet (PP port) of the lifting valve group 4 through a pipeline, the oil outlets are respectively connected to the oil inlets of the first pilot proportional valve 10 and the second pilot proportional valve 11, and the overflow port is connected to the oil drain port (DR port) through a pipeline, so as 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 (pa port) of the main lifting valve 12 through a pipeline; the oil outlet of the second pilot proportional valve 11 is connected to the second control port (pb port) of the main lifting valve 12 through a pipeline; the first pilot proportional valve 10 and the second pilot proportional valve 11 receive the output pressure instruction of the vehicle controller and output oil pressure according to the output pressure instruction. The size of the oil pressure output by the first pilot proportional valve 10 and the second pilot proportional valve 11 is controlled by the size of the output current of the vehicle controller. 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) through pipelines.

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

[0046] The main lifting valve 12 is the main element to control the action of the lifting oil cylinder (left lifting oil cylinder 5 and right lifting oil cylinder 6), which can control the four actions of lifting, lowering, holding and floating of the carriage. The main lifting valve 12 has a load control valve 24 integrated in the valve core, which can prevent the rear pulling force from causing damage to the lifting oil cylinder when the carriage is lifted to a high position.

[0047] The hydraulic control valve 13 is used to maintain the pressure difference between the oil inlet of the main lifting valve 12 and the first main lifting valve oil outlet and the second main lifting valve oil outlet, so that the pressure difference before and after the main lifting valve 12 is kept constant. 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 lifting valve 12 through a pipeline, and the oil outlet of the hydraulic control valve 13 is connected to the oil inlet of the overflow valve 14 and the control port of the first unloading valve 16 and the second unloading valve 17 through a pipeline. The function of the hydraulic control valve 13 is to transmit the load pressure of the lifting oil cylinder (left lifting oil cylinder 5 and right lifting oil cylinder 6) to the outlet of the lifting oil pump 3 when the carriage is lifted, to control the opening of the first unloading valve 16 and the second unloading valve 17, and to keep the pressure difference before and after the main lifting valve 12 constant. The control port of the hydraulic control valve 13 is connected to the second control port (pb port) through a pipeline, and the pressure of the second control port (pb port) of the main lifting valve 12 is used to adjust the position of the valve core of the hydraulic control valve 13, to adjust the opening of the first unloading valve 16 and the second unloading valve 17, and to adjust the outlet oil pressure of the lifting oil pump 3, so as to keep the pressure difference before and after the main lifting valve 12 stable. The oil outlet of the hydraulic control valve 13 is connected to the main load pressure feedback signal outlet (LS port) of the lifting 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 port of the first unloading valve 16 and the second unloading valve 17 through a pipeline. The third damping hole 23 is provided to prevent the fluctuation of the load pressure feedback by the hydraulic control valve 13 from causing the fluctuation of the output oil pressure of the lifting oil pump 3.

[0048] The oil outlet of the overflow valve 14 is connected to the drain port (DR port) through a pipeline, which functions to limit the maximum oil pressure value output by the lifting oil pump 3 to be no more than the pressure setting value of the overflow valve 14, and if it exceeds, the drain port (DR port) is connected to send hydraulic oil into the hydraulic oil tank 1.

[0049] The cut-off valve 15 is an electromagnetic valve, the oil inlet is connected to the control port of the first unloading valve 16, the control port of the second unloading valve 17, the oil inlet of the overflow valve 14 and the third damping hole 23 through a pipeline, and the oil outlet is connected to the drain port (DR port) through a pipeline. When the carriage is not lifted or lowered, the solenoid of the cut-off valve 15 is powered, the oil return port of the first pilot proportional valve 10 and the second pilot proportional valve 11 is connected to the drain port (DR port), the oil of the control oil pump 8 is returned to the hydraulic oil tank 1 through the drain port (DR port), so that the outlet oil pressure of the control oil pump 8 is close to zero, reducing the energy loss of the lifting device.

[0050] The first unloading valve 16 and the second unloading valve 17 are solenoid valves, the oil outlet of the first unloading valve 16 and the second unloading valve 17 is connected to the main oil return port (T port) through a pipeline, the oil inlet of the first unloading valve 16 and the second unloading valve 17 is connected to the oil outlet of the lifting oil pump 3, when the carriage is not in lifting or lowering action, the first unloading valve 16 and the second unloading valve 17 are powered on, and the oil output by the lifting oil pump 3 is directly returned 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 arranged to return the oil in the lifting oil cylinder (the left lifting oil cylinder 5 and the right lifting oil cylinder 6) to the hydraulic oil tank 1 by gravity in an emergency.

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

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

[0054] The detection port MA, the detection port MB, the detection port Ma, the detection port Mb, the main detection port LS, the detection port MP, the first detection port LS1 and the 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 (A port) through a pipeline, the detection port MB is connected to the second oil outlet (B port) through a pipeline, the detection port Ma is connected to the first control port (pa port) of the main lifting valve 12 through a pipeline, the detection port Mb is connected to the second control port (pb port) of the main lifting valve 12 through a pipeline, the detection port MP is connected to the oil inlet (P port) of the lifting 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 suction port of the control oil pump 8 is connected to the hydraulic oil tank 1 through a pipeline, and the discharge port is connected to the pilot inlet (PP port) of the lifting valve group 4 through a pipeline, for forming a control oil pressure and transmitting the control oil pressure to the lifting valve group 4. The control oil pump 8 is a small-displacement gear pump, and the suction port of the control oil pump 8 is provided with a second suction filter screen 7 connected to the hydraulic oil tank 1 through a pipeline.

[0056] The method for using the mine dump truck electro-hydraulic proportional lifting control device includes the following working modes:

[0057] (1) When the vehicle is in an off state, the engine does not operate, the lifting oil pump 3 and the control oil pump 8 do not output pressure oil, and the entire mine dump truck electro-hydraulic proportional lifting control device does not work.

[0058] (2) When the vehicle is in a running state, the engine drives the lifting oil pump 3 and the control oil pump 8 to work, the vehicle controller detects that the vehicle compartment is completely lowered on the vehicle frame, and the vehicle controller outputs an electric signal to electrify the electromagnet of the cut-off valve 15. At this time, the first unloading valve 16 and the second unloading valve 17 are electrified and connected, the oil inlet is communicated with the main oil return port (T port), and the oil output by the lifting oil pump 3 is directly returned to the hydraulic oil tank 1. The pressure oil output by the control oil pump 8 is adjusted to 30 bar by the pressure reducing valve 9 and output to the oil inlets of the first pilot proportional valve 10 and the second pilot proportional valve 11. The proportional electromagnet of the first pilot proportional valve 10 and the second pilot proportional valve 11 does not receive the output electric 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 have any action, and the entire system is in a standby state.

[0059] (3) The driver operates the lifting button in the cab, at this time the vehicle controller sends an electric signal to the first pilot proportional valve 10, and sends an electric signal to the cut-off valve 15, the cut-off valve 15 is disconnected, the first pilot proportional valve 10 outputs 28 bar of pilot oil to act on the first control port (pa port) of the main lifting valve 12, and drives the valve core of the main lifting valve 12 to work in the lifting position. The pressure oil output by the lifting oil pump 3 passes through the main lifting valve 12, is output from the second oil outlet (B port) of the lifting valve group 4, and enters the large cavity of the left lifting oil cylinder 5 and the right lifting oil cylinder 6, so that the vehicle compartment realizes the lifting action. At the same time, the oil pressure value of the second oil outlet (B port) is also fed back to the control port 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 degree of the first unloading valve 16 and the second unloading valve 17, and keep the pressure difference between the oil inlet and the oil outlet of the main lifting valve 12 at a stable value.

[0060] (4) Driver releases the lifting button in the cab, at this time the whole vehicle controller stops sending electric signal to the first pilot proportional valve 10, and sends electric 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 reset 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 in the second oil outlet (B port) of the lifting valve group 4, so that the carriage realizes the holding action, at this time the electromagnet of the cut-off valve 15 is electrified, the control ports of the first unloading valve 16 and the second unloading valve 17 are communicated with the oil return 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) Driver operates the lowering button in the cab, at this time the whole vehicle controller sends electric signal to the second pilot proportional valve 11, and stops sending electric signal to the cut-off valve 15, the second pilot proportional valve 11 outputs 28 bar of pilot oil to act on the pb port of the main lifting valve 12 and the control port of the hydraulic control valve 13, and drives the valve core of the main lifting valve 12 to work in the lowering position; the pressure oil output by the lifting oil pump 3 passes through the main lifting valve 12 and is output from the first oil outlet (A port) of the lifting valve group 4 to enter the small cavities of the left lifting oil cylinder 5 and the right lifting oil cylinder 6, so that the carriage realizes the lowering action; at the same time, the oil pressure value of the first oil outlet (A port) of the lifting 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 third damping hole 23 of the control position of the hydraulic control valve 13, so that the pressure difference between the inlet and outlet of the main lifting valve 12 is kept at a stable value.

[0062] (6) Driver operates the floating button in the cab, at this time the whole vehicle controller sends electric signal to the second pilot proportional valve 11, and sends electric signal to the cut-off valve 15, the second pilot proportional valve 11 outputs 13 bar of pilot oil to act on the second control port (pb port) of the main lifting valve 12 and the control port of the hydraulic control valve 13, and drives the valve core of the main lifting valve 12 to work in the floating position; the pressure oil output by the lifting oil pump 3 is cut off by the main lifting valve 12, the oil in the first oil outlet (A port) and the second oil outlet (B port) of the lifting valve group 4 enters the hydraulic oil tank 1 through the oil return port of the main lifting valve 12, the oil in the large cavities and small cavities of the left lifting oil cylinder 5 and the right lifting oil cylinder 6 is communicated with the hydraulic oil tank 1, and the carriage slowly realizes the lowering under the action of the dead weight; at this time the electromagnet of the cut-off valve 15 is electrified, the control ports of the first unloading valve 16 and the second unloading valve 17 are communicated with the main oil return port (T port), and the oil output by the lifting oil pump 3 returns to the hydraulic oil tank 1.

[0063] The terms used in the present application are illustrative and exemplary, rather than limiting terms. Since the present application can be implemented in various forms without departing from the spirit or essential characteristic thereof, it should also be understood that the above-described embodiments are not limited by any of the foregoing disclosure, but are widely interpreted, falling within the spirit and scope of the appended claims, whereby all changes and modifications thereto belong to the scope of the following claims.

Claims

1. An electro-hydraulic proportional lifting control device for a mining dump truck, characterized in that: include: Hydraulic oil tank, used to store oil; The lifting oil pump takes power from the engine power output end 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. Its first oil outlet is connected to the lowering port of the left lifting cylinder and the right lifting cylinder through a pipeline, and the second oil outlet is connected to the lifting port of the left lifting cylinder and the right lifting cylinder through a pipeline. The main oil return port and the oil discharge port are connected to the hydraulic oil tank through pipelines respectively; 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. The pressure reducing valve is used to reduce the control oil pressure to the set value and deliver it to the first pilot proportional valve and the second pilot proportional valve. Its oil inlet is connected to the pilot oil inlet of the lift valve group through a pipeline, and its oil outlet is connected to the oil inlet of the first pilot proportional valve and the second pilot proportional valve respectively. 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 an output pressure command from the vehicle controller and output or cut off the pressurized 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. A main lift valve is used to form pressurized oil at a first oil outlet and a 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 via a pipeline, the oil outlet of the first main lift valve is connected to the first oil outlet via a pipeline, the oil outlet of the second main lift valve is connected to the second oil outlet via a pipeline, and the oil return port is connected to the main oil return port via a pipeline. The oil outlet of the first main lift valve is provided with a first detection port, and the oil outlet of the second main lift valve is provided with a second detection port; A hydraulically controlled valve, used to maintain a constant pressure difference between the oil inlet of the main lift valve and the oil outlets of the first and second main lift valves, wherein the oil inlet is connected to the first and second detection ports of the main lift valves via pipelines, and the oil outlet is connected to the oil inlet of the cut-off valve via pipelines; The shut-off valve receives the output pressure command of the vehicle controller and outputs or cuts off the pressure oil according to the output pressure command. The oil inlet of the shut-off valve is connected to the control ports of the first unloading valve and the second unloading valve through pipelines, and the oil outlet is connected to the oil drain port through a pipeline. The first unloading valve and the second unloading valve are solenoid valves, the oil outlets of which are connected to the main oil return port through pipelines, and the 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 engine power output end to form the control oil pressure and transmit the control oil pressure to the pilot oil inlet of the lift 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 lift valve group through a pipeline; The oil outlet of the hydraulic control valve is connected to the third damping orifice through a pipeline, and the third damping orifice is connected to the control ports of the first unloading valve and the second unloading valve through a pipeline. The third damping orifice is used to prevent the load pressure fluctuation fed back by the hydraulic control valve from causing fluctuation in the output oil pressure 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; 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 is kept constant.

2. 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 drain port through a pipeline.

3. The electro-hydraulic proportional lifting control device for a mining dump truck according to claim 1, characterized in that: Also includes: Overflow valve, throttle valve, first unloading valve, second unloading valve, the oil inlet of the overflow valve is connected to the oil outlet of the hydraulic control valve through a pipeline, and the oil outlet is connected to the oil drain port through a pipeline. The overflow valve is used to limit the maximum oil pressure value output by the lifting oil pump. If it exceeds the limit, the oil drain 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.

4. 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 in the small chambers of the left lifting cylinder and the right lifting cylinder.

5. The method for using the electro-hydraulic proportional lifting control device for a mining dump truck according to any one of claims 1 to 4, characterized in that: include: When the vehicle is in operation, the engine drives the lift oil pump and the control oil pump. When the vehicle controller detects that the car body has completely fallen onto the frame, it outputs an electrical signal to energize the electromagnet of the shut-off valve. At this time, the first and second unloading valves are energized and connected, the oil inlet is connected to the main oil return port, and the oil output by the lift oil pump is directly returned 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. The pressure oil is output to the oil inlets of the first and second pilot proportional valves, respectively. The proportional electromagnets of the first and second pilot proportional valves wait for the output electrical signal of the vehicle controller. The first and second pilot proportional valves are disconnected, and the main lift valve is in a standby state. When the lift button is operated, the vehicle controller sends an electrical signal to the first pilot proportional valve, and the shut-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 lift valve, driving the valve core of the main lift valve to operate in the lift position. The pressure oil output by the lift oil pump passes through the main lift valve and is output from the second oil outlet of the lift valve group to the large chambers of the left and right lift cylinders, thereby lifting the car body. At the same time, the oil pressure value at the second oil outlet is also fed back to the control ports of the first and second unloading valves through the oil outlet of the hydraulic control valve via the third damping orifice, controlling the opening of the first and second unloading valves, so that the pressure difference between the oil inlet and oil outlet of the main lift valve remains stable. When the lowering 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, driving the valve core of the main lifting valve to work in the lowering position; the pressure oil output by the lifting oil pump passes through the main lifting valve and the first oil outlet of the lifting valve group into the small chambers of the left lifting cylinder and the right lifting cylinder, 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 and the third damping hole, so that the pressure difference between the oil inlet and oil outlet of the main lifting valve remains stable.

6. The method for using the electro-hydraulic proportional lifting control device for a mining dump truck according to claim 5, 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 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 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 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.

7. The method for using the electro-hydraulic proportional lifting control device for a mining dump truck according to claim 5, characterized in that: Operate the float button, 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 from 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.

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