A hydraulic system for a pure electric mine dump truck

Abstract

A kind of hydraulic system of pure electric mine dump truck, including battery, oil tank, electric pump, motor, filter, single-path liquid filling valve, brake module and steering module, motor drives electric pump to work, single-path liquid filling valve includes oil inlet P port, oil return port T port, for being communicated with brake module A port and for being communicated with steering module O port, one end of electric pump is connected with oil tank by oil pipe, the other end of electric pump is connected with the P port of single-path liquid filling valve by oil pipe, the T port of single-path liquid filling valve is connected with oil tank by oil pipe;Brake module includes energy storage device, parking valve, pedal valve and brake, steering module includes steering valve and two steering cylinders for controlling the steering of the left front wheel and right front wheel of dump truck respectively.The present application provides a set of hydraulic system specially applicable to electric mine dump truck, compared with the working mode of existing diesel engine driven hydraulic system, it is more energy-saving, environmental protection and low noise.

Description

Technical Field

[0001] This invention relates to the field of hydraulic systems for mining dump trucks, and in particular to a hydraulic system for a pure electric mining dump truck. Background Technology

[0002] Currently, the main types of underground mining dump trucks used in China are diesel underground dump trucks, overhead line underground dump trucks, and lithium-ion battery underground dump trucks. Among them, diesel underground dump trucks account for about 90%. The hydraulic system of diesel underground dump trucks requires the diesel engine to be constantly running to drive the oil pump. In addition, underground mines require high costs to manage the mine ventilation volume, which leads to energy waste, high noise, and serious pollution, which is inconsistent with the requirements of energy conservation and consumption reduction in mines.

[0003] The 20-ton pure electric mining dump truck is designed for the working environment of large underground mines. Its main features are zero emissions, low noise, and energy saving. The vehicle's power is replaced by a power battery instead of the original diesel engine. The vehicle is equipped with several parts, including a transmission system, a running system, a hydraulic (pneumatic) system, a power system, and an electrical system. The hydraulic system mainly consists of three major systems: a steering system, a braking system, and a lifting system. A dedicated hydraulic system needs to be designed to meet the requirements of the electric mining dump truck. Summary of the Invention

[0004] The purpose of this invention is to provide a hydraulic system for a pure electric mining dump truck, applicable to pure electric mining dump trucks, to achieve zero emissions, low noise, and energy saving. To achieve the above objectives, this invention adopts the following technical solution: A hydraulic system for a pure electric mining dump truck includes a battery, an oil tank, an electric pump, a motor, a filter, a single-channel filling valve, a braking module, and a steering module. The motor drives the electric pump. The single-channel filling valve includes an inlet (P port), a return port (T port), an A port for connecting to the braking module, and an O port for connecting to the steering module. One end of the electric pump is connected to the oil tank via an oil pipe, and the other end of the electric pump is connected to the P port of the single-channel filling valve via an oil pipe. The T port of the single-channel filling valve is connected to the oil tank via an oil pipe. The braking module includes an energy accumulator, a parking valve, and... The system includes a pedal valve and a brake. The A port of the single-channel filling valve is connected to the parking valve, pedal valve, and brake in sequence via an oil pipe. The accumulator is connected to the oil pipe between the single-channel filling valve and the parking valve via an oil pipe. The steering module includes a steering valve and two steering cylinders that control the steering of the left and right front wheels of the dump truck, respectively. The O port of the single-channel filling valve is connected to the P port of the steering valve via an oil pipe and supplies oil. The T port of the steering valve is connected to the oil tank to return oil. The RT port of the steering valve is connected to one end of the two steering cylinders via an oil pipe. The LT port of the steering valve is connected to the other end of the two steering cylinders via an oil pipe.

[0005] Furthermore, the single-channel filling valve includes a first two-position three-way directional valve and a second two-position three-way directional valve for controlling the first two-position three-way directional valve; when the valve core of the first two-position three-way directional valve is in the first position, the P port of the single-channel filling valve is connected to the O port, and the P port is connected to the A port through a check valve; when the valve core of the first two-position three-way directional valve is in the second position, the P port of the single-channel filling valve is connected to the O port through an adjustable flow valve, and the P port is connected to the A port through a check valve; the second two-position three-way directional valve includes an A port connected to the check valve, a B port connected to the control terminal W port of the first two-position three-way directional valve, and a T port connected to the oil tank; when the valve core of the second two-position three-way directional valve is in the first position, the A port is closed, and the B port and the T port are connected; when the valve core of the second two-position three-way directional valve is in the second position... When the parking valve and pedal valve are in the first position, port A is connected to port B, and port T is closed. Both the parking valve and the pedal valve are first three-position three-way valves. The first three-position three-way valve includes an oil inlet port P, an oil return port T, and a working oil port A. When the valve core of the first three-position three-way valve is in the first position, port P and port A are closed, and port A is connected to port T for oil return. When the valve core of the first three-position three-way valve is in the second position, port P, port A, and port T are closed. When the valve core of the first three-position three-way valve is in the third position, port P and port A are connected, and port A is closed to port T. The parking valve's P port and the single-way filling valve's A port are connected through an oil pipe. The parking valve's T port is connected to the oil tank. The parking valve's A port is connected to the pedal valve's P port through an oil pipe. The pedal valve's T port is connected to the oil tank. The pedal valve's A port is connected to the brake through an oil pipe.

[0006] Furthermore, the braking module also includes a three-way valve and a manual pump. The manual pump is connected to the oil tank via an oil pipe, and the output end of the manual pump and port A of the single-channel filling valve are connected to the accumulator via the three-way valve.

[0007] Furthermore, it also includes several pressure sensors and pressure gauges. Pressure gauges are respectively installed between the electric pump and the filter, between the parking valve and the single-way filling valve, and between the pedal valve and the brake. Pressure sensors are respectively installed between the electric pump and the filter, and between the pedal valve and the brake.

[0008] Furthermore, the steering valve is a three-position four-way valve. When the valve core of the steering valve is in the middle position, the P port of the steering valve is connected to the T port through a one-way valve for oil return. When the valve core of the steering valve is in one side position, the P port of the steering valve is connected to the RT port for oil inlet, and the LT port is connected to the T port for oil return. When the valve core of the steering valve is in the other side position, the P port of the steering valve is connected to the LT port for oil inlet, and the RT port is connected to the T port for oil return.

[0009] Furthermore, it also includes a lifting module, which includes a lifting pump, a power take-off (PTO), a lifting valve, a lifting cylinder, and a pneumatic control unit. One end of the lifting pump is connected to the fuel tank via an oil pipe, and the output end of the lifting pump is connected to the lifting valve and the lifting cylinder in sequence via an oil pipe. The PTO is located on one side of the lifting pump and transmits the power from the dump truck's main motor to the lifting pump. The pneumatic control unit includes a pneumatic control valve, which controls the PTO to connect to or disconnect from the lifting pump via an air circuit. The pneumatic control valve controls the valve core position of the lifting valve via an air circuit, thereby controlling the working state of the lifting cylinder.

[0010] Furthermore, the lifting valve includes a second three-position three-way valve. The output end of the lifting pump is connected to the P port of the second three-position three-way valve through a check valve. The T1 port of the second three-position three-way valve is connected to the oil tank for return flow, and the A port of the second three-position three-way valve is connected to the lifting cylinder. When the valve core of the second three-position three-way valve is in the first position, the P port and the T1 port are connected, and the A port is disconnected. When the valve core of the second three-position three-way valve is in the second position, the P port and the A port are connected to supply oil to the lifting cylinder, and the T1 port is disconnected. When the valve core of the second three-position three-way valve is in the third position, both the P port and the A port are connected to the T1 port, and the lifting cylinder returns oil and descends.

[0011] Furthermore, the lifting valve also includes an overflow valve, the input end of which is connected to the oil pipe between the second three-position three-way valve and the lifting cylinder, and the output end of which is connected to the oil tank through an oil pipe.

[0012] Furthermore, the pneumatic control unit also includes an air cylinder, the air inlet of which is connected to an air inlet, and the air outlet of which is connected to and supplies air to the pneumatic control valve. The pneumatic control valve includes a three-position five-way valve and a switching valve. When the valve core of the three-position five-way valve is in the first position, ports A and C are connected, ports B and E are connected, and port D is closed. When the valve core of the three-position five-way valve is in the second position, ports A and D are connected, and ports B, C, and E are closed. When the valve core of the three-position five-way valve is in the third position... When set, ports A and C of the three-position five-way valve are connected, while ports B, D, and E are closed. The air outlet of the air cylinder supplies air to port D of the three-position five-way valve. Ports C and E of the three-position five-way valve are connected externally to other control interfaces. Ports A and B of the three-position five-way valve are respectively connected to the two control interfaces LOWER and TIP of the second three-position three-way valve to control the valve core position of the second three-position three-way valve. The air outlet of the air cylinder supplies air to the power take-off. The switching valve is located between the power take-off and the air cylinder.

[0013] Furthermore, the pneumatic control unit also includes a limit valve, which is disposed between the TIP port of the second three-position three-way valve and the A port of the three-position five-way valve. The limit valve is a two-position two-way valve. When the valve core of the two-position two-way valve is in the first position, the A port of the three-position five-way valve is connected to the TIP port of the second three-position three-way valve; when the valve core of the two-position two-way valve is in the second position, the A port of the three-position five-way valve is cut off from the TIP port of the second three-position three-way valve.

[0014] Using the above technical solution, the dump truck's battery powers the entire system. A separate motor is used to drive the electric pump, which drives the hydraulic oil in the tank to the braking and steering modules to achieve braking and steering functions. Compared with the existing diesel engine-driven hydraulic system, this method is more energy-efficient, environmentally friendly, and quieter. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the braking module when the motor is off.

[0016] Figure 2 This is a schematic diagram of the braking module when the motor is powered on.

[0017] Figure 3 Schematic diagram of the braking module used to alleviate parking brake pressure.

[0018] Figure 4 Schematic diagram of a braking module for applying working braking.

[0019] Figure 5 Schematic diagram of the braking module for applying the parking brake.

[0020] Figure 6 This is a schematic diagram of the steering module when the motor is off.

[0021] Figure 7 This is a schematic diagram showing the steering module not steering when the motor is on.

[0022] Figure 8 This is a schematic diagram showing the steering module turning left when the motor is turned on.

[0023] Figure 9 This is a schematic diagram showing the steering module turning right when the motor is turned on.

[0024] Figure 10 This is a schematic diagram of the lifting module when the main motor of the dump truck is off.

[0025] Figure 11 This is a schematic diagram of the lifting module when the main motor of the dump truck is turned on.

[0026] Figure 12 This is a schematic diagram of the cargo box in the lifted state.

[0027] Figure 13 This is a schematic diagram of the lifting module in the cargo box holding position.

[0028] Figure 14 This is a schematic diagram of the lifting module in the cargo box's limited position state.

[0029] Figure 15 This is a schematic diagram of the cargo box in the lowered state. Detailed Implementation

[0030] The present invention will now be described in conjunction with the accompanying drawings and specific embodiments.

[0031] like Figure 1 , 6 As shown in Figure 10, a hydraulic system for a pure electric mining dump truck includes a battery, an oil tank 1, an electric pump 2, a motor, a filter 3, a single-channel filling valve 5, a braking module 6, a steering module 7, a lifting module 8, several pressure sensors 9, and several pressure gauges 10. The electric pump 2 is driven by a separately installed motor, and the dump truck's battery powers the entire system.

[0032] The single-channel filling valve 5 includes an oil inlet P port, an oil return port T port, an A port for connecting to the brake module 6, and an O port for connecting to the steering module 7. One end of the electric pump 2 is connected to the oil tank 1 through an oil pipe, and the other end of the electric pump 2 is connected to the P port of the single-channel filling valve 5 through an oil pipe. The T port of the single-channel filling valve 5 is connected to the oil tank 1 through an oil pipe. The single-channel filling valve 5 includes a first two-position three-way directional valve 11 and a second two-position three-way directional valve 12 for controlling the first two-position three-way directional valve 11. When the valve core of the first two-position three-way directional valve 11 is in the first position, the P port of the single-channel filling valve 5 is connected to the O port, and the P port is connected to the A port through a check valve. When the valve core of the first two-position three-way directional valve 11 is in the second position, the P port of the single-channel filling valve 5 is connected to the O port through an adjustable flow valve, and the P port is connected to the A port through a check valve. The second two-position three-way directional valve 12 includes an A port connected to the check valve, a B port connected to the control terminal W port of the first two-position three-way directional valve 11, and a T port connected to the oil tank 1. When the valve core of the second two-position three-way directional valve 12 is in the first position, the A port is closed, and the B port and the T port are connected. When the valve core of the second two-position three-way directional valve 12 is in the second position, the A port and the B port are connected, and the T port is closed.

[0033] The specific structure of braking module 6 is as follows: The braking module 6 includes an energy accumulator 13, a parking valve 14, a pedal valve 15, a brake 16, a three-way valve 17, and a manual pump 18. Port A of the single-channel filling valve 5 is connected sequentially to the parking valve 14, the pedal valve 15, and the brake 16 via oil pipes. The energy accumulator 13 is connected to the oil pipes between the single-channel filling valve 5 and the parking valve 14 via oil pipes. The manual pump 18 is connected to the oil tank 1 via oil pipes, and the output end of the manual pump 18 and port A of the single-channel filling valve 5 are connected to the energy accumulator 13 via the three-way valve 17.

[0034] Both the parking valve 14 and the pedal valve 15 are first three-position three-way valves. The first three-position three-way valve includes an oil inlet port P, an oil return port T, and a working oil port A. When the valve core of the first three-position three-way valve is in the first position, the P port and the A port are cut off, and the A port is connected to the T port for oil return. When the valve core of the first three-position three-way valve is in the second position, the P port, the A port, and the T port are cut off. When the valve core of the first three-position three-way valve is in the third position, the P port and the A port are connected, and the A port is cut off from the T port. The P port of the parking valve 14 and the A port of the single-way filling valve 5 are connected through an oil pipe. The T port of the parking valve 14 is connected to the oil tank 1. The A port of the parking valve 14 is connected to the P port of the pedal valve 15 through an oil pipe. The T port of the pedal valve 15 is connected to the oil tank 1. The A port of the pedal valve 15 is connected to the brake 16 through an oil pipe.

[0035] Pressure gauges 10 are installed between the electric pump 2 and the filter 3, between the parking valve 14 and the single-channel filling valve 5, and between the pedal valve 15 and the brake 16. Pressure sensors 9 are installed between the electric pump 2 and the filter 3, and between the pedal valve 15 and the brake 16.

[0036] The specific structure of steering module 7 is as follows: The steering module 7 includes a steering valve 19 and two steering cylinders 20 that control the steering of the left and right front wheels of the dump truck, respectively. The O port of the single-channel filling valve 5 is connected to the P port of the steering valve 19 through an oil pipe and supplies oil. The T port of the steering valve 19 is connected to the oil tank 1 to realize oil return. The RT port of the steering valve 19 is connected to one end of the two steering cylinders 20 through an oil pipe, and the LT port of the steering valve 19 is connected to the other end of the two steering cylinders 20 through an oil pipe.

[0037] Steering valve 19 is a three-position four-way valve. When the valve core of steering valve 19 is in the middle position, the P port of steering valve 19 is connected to the T port through a check valve for oil return. When the valve core of steering valve 19 is in one side position, the P port of steering valve 19 is connected to the RT port for oil inlet, and the LT port is connected to the T port for oil return. When the valve core of steering valve 19 is in the other side position, the P port of steering valve 19 is connected to the LT port for oil inlet, and the RT port is connected to the T port for oil return.

[0038] The specific structure of lifting module 8 is as follows: The lifting module 8 includes a lifting pump 21, a power take-off (PTO) 22, a lifting valve 23, a lifting cylinder 24, and a pneumatic control unit. One end of the lifting pump 21 is connected to the oil tank 1 via an oil pipe. The output end of the lifting pump 21 is connected to the lifting valve 23 and the lifting cylinder 24 in sequence via an oil pipe. The PTO 22 is located on one side of the lifting pump 21 and transmits the power of the dump truck's main motor to the lifting pump 21.

[0039] The lifting valve 23 includes a second three-way valve 25 and a relief valve 26. The output end of the lifting pump 21 is connected to the P port of the second three-way valve 25 via a check valve. The T1 port of the second three-way valve 25 is connected to the oil tank 1 for return flow. The A port of the second three-way valve 25 is connected to the lifting cylinder 24. The input end of the relief valve 26 is connected to the oil pipe between the second three-way valve 25 and the lifting cylinder 24. The output end of the relief valve 26 is connected to the oil tank 1 via an oil pipe. When the valve core of the second three-way valve 25 is in the first position, the P port and the T1 port are connected, and the A port is disconnected. When the valve core of the second three-way valve 25 is in the second position, the P port and the A port are connected to supply oil to the lifting cylinder 24, and the T1 port is disconnected. When the valve core of the second three-way valve 25 is in the third position, both the P port and the A port are connected to the T1 port, and the lifting cylinder 24 returns oil and descends.

[0040] The pneumatic control unit includes a pneumatic control valve 27, an air cylinder 28, and a limit valve 29. The air inlet of the air cylinder 28 is connected to the air inlet, and the air outlet of the air cylinder 28 is connected to the pneumatic control valve 27 and supplies air to the pneumatic control valve 27. The pneumatic control valve 27 controls the power take-off 22 to connect to or disconnect from the lifting pump 21 through the air circuit. The pneumatic control valve 27 controls the valve core position of the lifting valve 23 through the air circuit, thereby controlling the working state of the lifting cylinder.

[0041] Specifically, the pneumatic control valve 27 includes a three-position five-way valve 30 and a switching valve 31. When the valve core of the three-position five-way valve 30 is in the first position, ports A and C of the three-position five-way valve 30 are connected, ports B and E are connected, and port D is closed. When the valve core of the three-position five-way valve 30 is in the second position, ports A and D of the three-position five-way valve 30 are connected, and ports B, C, and E are closed. When the valve core of the three-position five-way valve 30 is in the third position, ports A and C of the three-position five-way valve 30 are connected, and ports B and D are closed. The air outlet of the air cylinder 28 is supplied with air from the D port of the three-position five-way valve 30. The C and E ports of the three-position five-way valve 30 are connected to the outside and lead to other control interfaces. The A and B ports of the three-position five-way valve 30 are respectively connected to the LOWER port and TIP port of the two control interfaces of the second three-position three-way valve 25 to control the valve core position of the second three-position three-way valve 25. The air outlet of the air cylinder 28 is supplied with air from the power take-off 22. The switching valve 31 is set between the power take-off 22 and the air cylinder 28.

[0042] The limit valve 29 is located between the tip port of the second three-position three-way valve 25 and the A port of the three-position five-way valve 30. The limit valve 29 is a two-position two-way valve. When the valve core of the two-position two-way valve is in the first position, the A port of the three-position five-way valve 30 is connected to the tip port of the second three-position three-way valve 25. When the valve core of the two-position two-way valve is in the second position, the A port of the three-position five-way valve 30 is cut off from the tip port of the second three-position three-way valve 25.

[0043] The specific working principle of the present invention will be explained below: 1. Working principle of braking module 6.

[0044] The hydraulic braking module 6 mainly includes several working states such as turning off the motor, turning on the motor, applying the parking brake, releasing the parking brake, and applying the working brake.

[0045] (1) Motor off state: The pure electric mining dump truck uses hydraulic braking, with brakes 16 in three positions: front, middle, and rear. Brakes 16 are wet spring brakes. When the motor is off, the single-channel filling valve 5 cuts off the pressure oil inside the accumulator 13, ensuring that the pressure oil inside the wet spring brake 16 flows back to the oil tank 1 from the parking valve 14, thus maintaining the vehicle in the parking brake state. Figure 1 This is a schematic diagram of the braking module 6 when the motor is off.

[0046] (2) Motor on-state: When the motor is turned on, hydraulic oil flows from the oil tank 1 into the single-way filling valve 5. The oil pressure causes the internal reversing valve to switch the oil circuit interface, allowing hydraulic oil to enter the accumulator 13. When the pressure reaches 12.5 MPa, the hydraulic oil flows back to the oil tank 1 from the T port of the single-way filling valve 5 to release pressure, ensuring the stability of the internal pressure value of the hydraulic system. Figure 2 This is a schematic diagram of the braking module 6 when the motor is on.

[0047] (3) Run the motor to release the parking brake: When the motor is turned on, hydraulic oil flows from the oil tank 1 into the single-way filling valve 5. The oil pressure causes the internal reversing valve to switch the oil circuit interface, allowing hydraulic oil to enter the accumulator 13. When the pressure reaches 12.5 MPa, the hydraulic oil flows back to the oil tank 11 from the T port of the single-way filling valve 54 to release pressure and ensure the stability of the internal pressure value of the system. Pulling down the parking valve 14 handle connects the hydraulic oil in the accumulator 13 and the hydraulic oil in the brake 16, releasing the brakes under the action of the hydraulic oil. Figure 3 Schematic diagram of braking module 6, which activates the motor to relieve the parking brake.

[0048] (4) Run the motor and apply the working brake: When the motor is turned on and the operator depresses the foot pedal, the pedal valve 15 blocks the oil pipe connection between the accumulator 13 and the brake 16, causing the hydraulic oil inside the brake 16 to flow back into the oil tank 1 through the pedal valve 15, thus locking the brake 16 and achieving the braking effect. Figure 4 The schematic diagram of braking module 6 when the motor is turned on and the working brake is applied.

[0049] (5) Run the motor and apply the parking brake: When the motor is turned on and the operator pulls the parking lever, the parking valve 14 blocks the oil pipe between the brake 16 and the accumulator 13, causing the hydraulic oil inside the brake 16 to flow back into the oil tank 1 through the parking valve 14, thus locking the brake 16 and providing parking braking. Figure 5 This is a schematic diagram showing the principle of applying the parking brake to turn on the motor.

[0050] 2. Working principle of steering module 7.

[0051] The chassis of the pure electric mining dump truck is designed with hydraulic power steering. The steering module 7 realizes the control of the vehicle's driving direction. The steering of the pure electric mining dump truck is driven by an electric motor, which mainly includes four working states: motor off, motor on, left turn, and right turn.

[0052] (1) Motor off: Under this condition, motor 2 is in the off state, there is no hydraulic oil inside the hydraulic steering module 7, the pressure oil inside steering valve 19 and steering cylinder 20 is in a static state, steering valve 19 is in the neutral position, and the oil circuit circulation between electric pump 2, oil tank 1 and steering cylinder 20 is cut off. Figure 6 This is a schematic diagram of the hydraulic steering principle when the motor is off.

[0053] (2) The motor is on, but there is no direction of rotation: After the motor rotates, the hydraulic oil in the hydraulic oil tank 1 flows to the single-way filling valve 5 through the motor pump. Under the action of the hydraulic oil, the two sets of reversing valves inside the single-way filling valve 5 switch simultaneously, storing energy in the accumulator 13 inside the brake. After 2 seconds, the oil flows out through the P port of the lower single-way filling valve 5, and the entire hydraulic steering module 7 has an oil circuit circulation. Figure 7 The schematic diagram for activating the hydraulic steering module 7 for the motor.

[0054] (3) Start the motor and turn left: When the steering wheel is turned to the left, the inlet and outlet ports of the steering valve 19 switch to the right position. Hydraulic oil from the electric pump 2 flows into the steering valve 19 through the single-way filling valve 5. The steering valve 19 then distributes the hydraulic oil to the left and right steering cylinders, thus realizing the vehicle's steering function. Figure 8 This is a schematic diagram of the hydraulic steering module 7 in the left-turn state with the motor turned on.

[0055] (4) Start the motor and turn right: When the steering wheel is turned to the right, the inlet and outlet ports of the steering valve 19 switch to the left position. Hydraulic oil from the electric pump 2 flows through the single-way filling valve 5 into the steering valve 19, which then distributes the hydraulic oil to the left and right steering cylinders, thus realizing the vehicle's steering function. Figure 9 This is a schematic diagram of the hydraulic steering mechanism when the motor is on and the steering wheel is in right-turn mode.

[0056] 3. Working principle of lifting module 8.

[0057] The power source of the lifting module 8 of the pure electric mining dump truck mainly relies on the main motor of the dump truck to drive the power take-off 22, thereby controlling the rotation of the lifting pump 21. The lifting pump 21 is a gear pump. When lifting is required, the lifting control handle is moved to the lifting position. The hydraulic oil from the lifting pump 21 enters the rodless chamber of the lifting cylinder 24 through the lifting valve 23, pushing the piston rod and thus pushing the cargo box upward to achieve lifting. The system control mainly relies on the pneumatic control unit to change the position of the inlet and outlet of the lifting valve 23, thereby controlling the flow of hydraulic oil to achieve functions such as lifting, holding, and power lowering.

[0058] (1) The main motor of the dump truck is turned off: In this state, the pneumatic control valve 27 is in the off position, the power take-off 22 is not engaged, the lifting pump 21 is not working, and there is no hydraulic oil flowing in the lifting module 8. At this time, both the pneumatic control valve 27 and the lifting valve 23 are in the intermediate stop position, and the lifting cylinder 24 is in the lowest position. Figure 10 Hydraulic schematic diagram for shutting down the lifting system for the motor.

[0059] (2) The main motor of the dump truck is turned on, and the lifting pump 21 starts operating: When the truck bed needs to be lifted, the power take-off (PTO) 22 and the lifting pump 21 are first connected. Specifically, the pneumatic control valve 27 is energized, the valve core of the switching valve 31 moves to the left, connecting the control air circuit of the PTO 22, and connecting the PTO 22 with the shaft of the lifting pump 21. The power is then transmitted to the lifting pump 21 through the dump truck's main motor, causing the lifting pump 21 to rotate at high speed and generate high-pressure oil. At this time, the lifting valve 23 is in the neutral position, so the high-pressure oil flows back to the oil tank 1 through the oil passage inside the lifting valve 23 and is filtered by the return oil filter. Figure 11 Hydraulic schematic diagram of lifting module 8 for motor activation.

[0060] (3) The main motor of the dump truck is turned on, the lifting pump 21 is running, and the cargo box is in the lifting state: When lifting the cargo box, turn the pneumatic control valve 27 to the lifting position to connect the system air pressure to the lifting channel of the pneumatic control valve 27. The system air pressure flows through the pneumatic control valve 27 and the limit valve 29, acting on the inside of the lifting valve 23 and driving the valve core to move. Hydraulic oil enters the lifting cylinder 24 through the lifting valve 23 and lifts the piston rod. If the oil pressure in the lifting module 8 is too high, the bypass relief valve 26 will open to prevent high oil pressure from damaging the lifting pump 21 and pipelines. Figure 12 The hydraulic schematic diagram of the lifting module 8 is shown when the motor is turned on and the lifting mode is activated.

[0061] (4) The main motor of the dump truck is turned on, the lifting pump 21 is running, and the cargo box remains in the same position: The hydraulic lifting module 8 can stop the movement of the lifting cylinder 24 at any time. By turning the pneumatic control valve 27 to the stop position, the compressed air acting on the lifting valve 23 will be discharged from the exhaust port of the pneumatic control valve 27. Then, the valve core of the lifting valve 23 will return to the middle position under the action of the spring, and the hydraulic oil in the lifting cylinder 24 will stop flowing in or out, and the lifting cylinder 24 will be in a stationary state. Figure 13 Hydraulic schematic diagram of lifting module 8 with motor on and in the holding state.

[0062] (5) The main motor of the dump truck is turned on, the lifting pump 21 is running, and the cargo box is in the limit position: When the cargo box rises to the set angle, the valve core of the limit valve 29 is triggered to move, cutting off the air passage between the air system and the lifting valve 23. Compressed air is discharged from the exhaust port of the limit valve 29, the valve core of the lifting valve 23 returns to the middle position, and the lifting cylinder 24 stops rising and remains in the maximum angle holding state. Figure 14 This is a hydraulic schematic diagram of the lifting system with the motor turned on and in the limit position.

[0063] (6) The main motor of the dump truck is turned on, the lifting pump 21 is running, and the cargo box is in the lowered state: When the cargo box is lowered, the pneumatic control valve 27 needs to be turned to the lowering position. The system air pressure enters the lifting valve 23 through the lowering interface of the pneumatic control valve 27, pushing the valve core to move and connecting the lifting cylinder 24 with the hydraulic oil port of the lifting valve 23. The high-pressure oil in the lifting cylinder 24 flows back to the oil tank 1 and is filtered through the return oil filter. Figure 15 This is a hydraulic schematic diagram of the lifting system in the lowering state with the motor turned on.

[0064] Using the above technical solution, the dump truck's battery powers the entire system. A separate motor is used to drive the electric pump 2, which drives the hydraulic oil in the oil tank 1 to the braking module 6 and the steering module 7 to achieve braking and steering functions. For the lifting module, the dump truck's main motor drives the lifting pump through a power take-off. This invention provides a hydraulic system specifically designed for electric mining dump trucks. Compared with the existing diesel engine-driven hydraulic system, it is more energy-efficient, environmentally friendly, and has lower noise.

[0065] The above are merely preferred embodiments of the present invention and are not intended to limit the invention. For those skilled in the art, the present invention can have various modifications, combinations, and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A hydraulic system for a pure electric mining dump truck, characterized in that: The system includes a battery, a fuel tank, an electric pump, a motor, a filter, a single-channel filling valve, a braking module, and a steering module. The motor drives the electric pump. The single-channel filling valve includes an inlet (P port), an outlet (T port), an outlet (A port) for connecting to the braking module, and an outlet (O port) for connecting to the steering module. One end of the electric pump is connected to the fuel tank via an oil pipe, and the other end of the electric pump is connected to the P port of the single-channel filling valve via an oil pipe. The T port of the single-channel filling valve is connected to the fuel tank via an oil pipe. The braking module includes an energy accumulator, a parking valve, a pedal valve, and a brake. Port A of the single-channel filling valve is connected to the parking valve, the pedal valve, and the brake in sequence via an oil pipe. The energy accumulator is connected to the oil pipe between the single-channel filling valve and the parking valve via an oil pipe. The steering module includes a steering valve and two steering cylinders that control the steering of the left and right front wheels of the dump truck, respectively. The O port of the single-channel filling valve is connected to the P port of the steering valve through an oil pipe and supplies oil. The T port of the steering valve is connected to the oil tank to realize oil return. The RT port of the steering valve is connected to one end of the two steering cylinders through an oil pipe. The LT port of the steering valve is connected to the other end of the two steering cylinders through an oil pipe. The single-channel filling valve includes a first two-position three-way reversing valve and a second two-position three-way reversing valve for controlling the first two-position three-way reversing valve; When the valve core of the first and second position three-way directional valve is in the first position, the P port of the single-channel filling valve is connected to the O port, and the P port is connected to the A port through the check valve. When the valve core of the first and second position three-way directional valve is in the second position, the P port of the single-channel filling valve is connected to the O port through the adjustable flow valve, and the P port is connected to the A port through the check valve. The second two-position three-way directional valve includes port A, which is connected to the check valve; port B, which is connected to the control terminal W of the first two-position three-way directional valve; and port T, which is connected to the oil tank. When the valve core of the second two-position three-way directional valve is in the first position, port A is closed, and ports B and T are connected. When the valve core of the second two-position three-way directional valve is in the second position, ports A and B are connected, and port T is closed. Both the parking valve and the pedal valve are first three-position three-way valves. The first three-position three-way valve includes an oil inlet (P port), an oil return port (T port), and a working oil port (A port). When the valve core of the first three-position three-way valve is in the first position, the connection between the P port and the A port is closed, and the A port is connected to the T port for oil return. When the valve core of the first three-position three-way valve is in the second position, the connection between the P port, the A port, and the T port is closed. When the valve core of the first three-position three-way valve is in the third position, the P port and the A port are connected, and the A port is closed to the T port. The P port of the parking valve and the A port of the single-way filling valve are connected through an oil pipe. The T port of the parking valve is connected to the oil tank. The A port of the parking valve is connected to the P port of the pedal valve through an oil pipe. The T port of the pedal valve is connected to the oil tank. The A port of the pedal valve is connected to the brake through an oil pipe.

2. The hydraulic system for a pure electric mining dump truck according to claim 1, characterized in that: The braking module also includes a three-way valve and a manual pump. The manual pump is connected to the oil tank via an oil pipe, and the output end of the manual pump and port A of the single-channel filling valve are connected to the energy storage device via the three-way valve.

3. The hydraulic system for a pure electric mining dump truck according to claim 1, characterized in that: It also includes several pressure sensors and pressure gauges. Pressure gauges are installed between the electric pump and the filter, between the parking valve and the single-way filling valve, and between the pedal valve and the brake. Pressure sensors are installed between the electric pump and the filter, and between the pedal valve and the brake.

4. The hydraulic system for a pure electric mining dump truck according to claim 1, characterized in that: The steering valve is a three-position four-way valve. When the valve core is in the middle position, the P port of the steering valve is connected to the T port through a check valve for oil return. When the valve core is in one side position, the P port of the steering valve is connected to the RT port for oil inlet, and the LT port is connected to the T port for oil return. When the valve core is in the other side position, the P port of the steering valve is connected to the LT port for oil inlet, and the RT port is connected to the T port for oil return.

5. The hydraulic system for a pure electric mining dump truck according to any one of claims 1-4, characterized in that: It also includes a lifting module, which comprises a lifting pump, a power take-off (PTO), a lifting valve, a lifting cylinder, and a pneumatic control unit. One end of the lifting pump is connected to the fuel tank via an oil pipe, and the output end of the lifting pump is connected to the lifting valve and the lifting cylinder in sequence via an oil pipe. The PTO is located on one side of the lifting pump and transmits power from the dump truck's main motor to the lifting pump. The pneumatic control unit includes a pneumatic control valve, which controls the PTO to connect to or disconnect from the lifting pump via an air circuit. The pneumatic control valve controls the valve core position of the lifting valve via an air circuit, thereby controlling the working state of the lifting cylinder.

6. The hydraulic system for a pure electric mining dump truck according to claim 5, characterized in that: The lifting valve includes a second three-position three-way valve. The output end of the lifting pump is connected to the P port of the second three-position three-way valve through a check valve. The T1 port of the second three-position three-way valve is connected to the oil tank for return flow. The A port of the second three-position three-way valve is connected to the lifting cylinder. When the valve core of the second-third-position three-way valve is in the first position, port P and port T1 are connected, and port A is disconnected; when the valve core of the second-third-position three-way valve is in the second position, port P and port A are connected to supply oil to the lifting cylinder, and port T1 is disconnected; when the valve core of the second-third-position three-way valve is in the third position, both port P and port A are connected to port T1, and the lifting cylinder returns oil and descends.

7. The hydraulic system for a pure electric mining dump truck according to claim 6, characterized in that: The lifting valve also includes an overflow valve. The input end of the overflow valve is connected to the oil pipe between the second three-position three-way valve and the lifting cylinder, and the output end of the overflow valve is connected to the oil tank through the oil pipe.

8. The hydraulic system for a pure electric mining dump truck according to claim 6, characterized in that: The pneumatic control unit also includes an air cylinder, the air inlet of which is connected to an air inlet, and the air outlet of which is connected to a pneumatic control valve and supplies air to the pneumatic control valve. The pneumatic control valve includes a three-position five-way valve and an on / off valve. When the valve core of the three-position five-way valve is in the first position, ports A and C are connected, ports B and E are connected, and port D is closed. When the valve core of the three-position five-way valve is in the second position, ports A and D are connected, and ports B, C, and E are closed. When the valve core of the three-position five-way valve is in the third position, ports A and C are connected, and ports B, D, and E are closed. The air outlet of the air cylinder is supplied with air from port D of the three-position five-way valve. Ports C and E of the three-position five-way valve are connected to the outside and lead to other control interfaces. Ports A and B of the three-position five-way valve are respectively connected to the two control interfaces LOWER and TIP of the second three-position three-way valve to control the valve core position of the second three-position three-way valve. The air outlet of the air cylinder supplies air to the power take-off (PTO), and the switching valve is located between the PTO and the air cylinder.

9. The hydraulic system for a pure electric mining dump truck according to claim 8, characterized in that: The pneumatic control unit also includes a limit valve, which is located between the tip port of the second three-position three-way valve and the A port of the three-position five-way valve. The limit valve is a two-position two-way valve. When the valve core of the two-position two-way valve is in the first position, the A port of the three-position five-way valve is connected to the tip port of the second three-position three-way valve. When the valve core of the two-position two-way valve is in the second position, the A port of the three-position five-way valve is cut off from the tip port of the second three-position three-way valve.

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