A wide-body dump truck directly driven by a high-voltage motor

Abstract

A wide-body dump truck directly driven by a high-voltage motor includes an unpowered chassis, a power supply system, a drive system, a multi-stage thermal management system, an auxiliary electrical system, a hydraulic system, a body, and a control system. Under traction conditions, the power supply system distributes electrical energy to an auxiliary inverter and a traction inverter via a high-voltage box. The auxiliary inverter supplies power to a lifting motor and an all-in-one controller, which in turn drives an air compressor, a steering motor, a 24V battery, and a battery thermal management unit. The traction inverter controls the traction motor, which transmits power directly to the axle via a drive shaft. Under electric braking conditions, the braking energy of the traction motor is fed back to the power supply system via the traction inverter. A rescue steering mode and a merging lifting mode are added to the traditional hydraulic system. The cooling system integrates the cooling or heating requirements of key heat sources such as the battery thermal management unit, the ATS, and the air conditioning system into a unified, efficient management system.

Description

Technical Field

[0001] The present invention relates to the technical field of dump trucks, and in particular to a wide-body dump truck directly driven by a high-voltage motor. Background Art

[0002] Currently, the situation of energy conservation and emission reduction is particularly severe, and it is an irresistible trend for the construction machinery industry to accelerate the transformation to new energy. In the future market, the demand for pure electric wide-body dump trucks will continue to grow, and according to the development trend of the demand market for mine transport vehicles, pure electric wide-body dump trucks have extremely broad market prospects and space.

[0003] Existing large non-road pure electric wide-body dump trucks basically adopt the technical route of "motor + transmission". Its power transmission route is as follows: the energy of the power source is divided into two paths after passing through the high-voltage box, and two motors are controlled by two motor controllers respectively. The output torques of the motors are coupled and then decelerated and torque-increased by the transmission, and then the vehicle is driven to run. There are also individual manufacturers trying to adopt the power uninterrupted shifting technology, that is, the output torques of the two motors are first decelerated and torque-increased by the reducer and then coupled, which is equivalent to the coupling of two sets of power units at the output end. When shifting gears, only one set of power can be shifted, and the power of the other set of power units continues to maintain power output, so as to achieve power uninterrupted shifting.

[0004] Disadvantages of the existing technology:

[0005] 1. The reliability of the transmission is not high, affecting the vehicle utilization rate. Since the wide-body truck came into being, it has always followed the technical route of highway heavy trucks, so a large number of multi-gear transmissions are applied. Although it reduces the dependence on the engine performance, it also brings the problem of generally low reliability. After the wide-body truck enters the electrification era, the transmission still plays an important role, and every main engine factory is using it. Because the performance of the motor is better than that of the engine, especially the speed-torque characteristics of the motor have been greatly improved compared with the engine, so the number of gears of the transmission of electric vehicles is getting less and less, from 7 gears to 4 gears, and even to 3 gears and 2 gears. No matter how many gears, because they are all strengthened on the basis of the highway vehicle transmission, their reliability is not optimistic when applied in the complex and changeable mine working conditions. In addition to high failure rates, the transmission also has problems such as power interruption during shifting, shifting delay, and shifting shock. These problems will not only affect the driving experience but also pose safety hazards.

[0006] 2. Slow charging affects the vehicle utilization rate. At present, pure electric wide-body trucks all use energy-type power batteries with a charge-discharge rate of 1C and a voltage platform of basically 750V. The charging time for SOC20% - 90% is generally 80 - 90 minutes. Therefore, charging is generally carried out during rest time. If the vehicle utilization rate is to be further improved, there will be certain limitations.

[0007] 3. Insufficient electric braking ability. In most operating conditions of the tram, the motor is used for reverse dragging braking. While controlling the vehicle speed, it can also recover the kinetic energy of the vehicle. The main factors affecting the braking effect are the braking power of the motor and the feedback power of the battery system. Generally, the feedback power of the battery system should not be less than the electric braking power of the motor. Otherwise, the electric braking ability of the motor cannot be fully exerted. The peak charge-discharge rate of the energy-type power battery is relatively low. When the motor power is certain, in order to meet this condition, it is necessary to increase the vehicle's overall power storage. Increasing the power storage will inevitably increase the vehicle's overall cost, and the vehicle weight increases, reducing the vehicle's mass utilization coefficient. To balance the electric braking performance and the vehicle's overall cost, the common solution in the industry currently is to supplement the insufficient electric braking ability through an eddy current retarder. However, when the eddy current brake is in operation, it is a pure heat-generating device that will convert the vehicle's kinetic energy into heat and dissipate it, affecting energy recovery. The eddy current retarder is installed between the transmission and the axle. As a part of the transmission system, it changes one original drive shaft into two drive shafts and adds two universal joints, resulting in an efficiency loss. Together with the efficiency loss of its own rotation, the overall vehicle transmission efficiency drops by 3%.

[0008] 4. The thermal management system is relatively independent. For example, the battery thermal management, the motor and electronic control thermal management, and the cab air conditioner are three independent systems, resulting in waste of heat.

[0009] 5. The driving sources of the lifting and steering systems are single. Once a system fails, the vehicle will be unable to turn or lift, which is likely to cause road congestion and affect the operation of other vehicles during daily operations. Summary of the Invention

[0010] The technical problem to be solved by the present invention is to provide a wide-body dump truck with high-voltage motor direct drive to solve the technical problems existing in the prior art.

[0011] To solve the above technical problems, the technical solution of the present invention is: A wide-body dump truck with high-voltage motor direct drive includes a non-powered chassis, a power supply system, a drive system, a multi-stage thermal management system, an auxiliary electrical system, a hydraulic system, a vehicle body, and a control system;

[0012] The power battery system includes a power battery box, a high-voltage box, a BMS control box, and a charging box; the power battery box is respectively installed on both sides of the vehicle frame through two battery brackets; the high-voltage box concentrates all battery branches on a unified busbar to output current, and the high-voltage box is provided with a charging connector; the BMS control box communicates with the vehicle controller and the charging box through the CAN bus. The vehicle controller reads the data of the BMS control box through the CAN bus and displays the data on the dashboard. At the same time, charging control is realized through the communication between the BMS control box and the charging box;

[0013] The drive system includes a traction motor, a traction inverter, an auxiliary inverter and a motor controller; the traction motor is installed between the two longitudinal beams of the frame through a motor mounting seat, and the traction motor is arranged at an angle with the horizontal plane; the traction inverter and the auxiliary inverter are connected to the rear end of the high-voltage box pre-charging circuit, wherein the auxiliary inverter provides a power distribution line for the traction inverter; under traction conditions, the power supply system distributes electric energy to the auxiliary inverter and the traction inverter through the high-voltage box, wherein the auxiliary inverter supplies power to the lifting motor and the all-in-one controller, and the all-in-one controller then drives the air compressor, the steering motor, the 24V battery and the battery thermal management unit, the traction inverter controls the traction motor, and the traction motor directly transmits power to the axle through the drive shaft; under electric braking conditions, the braking energy of the traction motor is fed back to the power supply system through the traction inverter;

[0014] The multi-stage thermal management system includes a battery thermal management unit, an ATS and an air conditioning system; the air conditioning refrigeration and battery refrigeration share a compressor and condenser, and the refrigeration circuit is divided into two branches after passing through the condenser. The cab air conditioning branch is controlled by a combination valve, and the battery refrigeration branch is controlled by an electronically controlled expansion valve. The battery water circulation circuit and the battery refrigeration branch exchange heat through a first heat exchanger; when the battery and air conditioning need to be heated, the coolant flows through the traction motor and the PTC heater in sequence for heating. The heated coolant is proportionally distributed to the cab air conditioning and battery heating branches through a water valve, and the battery heating branch and the battery water circulation circuit exchange heat through a second heat exchanger; when the battery needs to be cooled and the cab air conditioning needs to be heated, the coolant flows through the traction motor, the third heat exchanger and the PTC heater in sequence. The heated coolant is distributed to the cab air conditioning through a water valve, and the compressor refrigerant passes through the third heat exchanger, the condenser, the electronically controlled expansion valve, and the first heat exchanger in sequence;

[0015] The hydraulic system includes a controller, a lifting motor, a lifting pump, a lifting cylinder, a lifting valve group, a steering motor, a steering pump, a steering cylinder and a steering valve group; when the steering motor or the steering pump fails and steering is required, a rescue command is sent to the controller by pressing the rescue steering switch, and the controller controls the lifting motor to start and controls the lifting valve group to cut off the circuit between the lifting pump and the lifting cylinder, connecting the lifting pump oil outlet and the steering cylinder so that the hydraulic oil pumped out by the lifting pump can flow into the steering system to achieve steering; when the lifting motor or the steering pump fails and lifting is required When the emergency lift is in operation, the controller sends a command to the controller by pressing the emergency lift switch. The controller controls the steering motor to start, and controls the steering valve group to cut off the circuit between the steering pump and the steering cylinder, and connects the steering pump oil outlet with the lifting cylinder, so that the hydraulic oil pumped out by the steering pump can flow into the lifting system to realize emergency lifting. During normal lifting, the controller controls the steering motor and the lifting motor to work at the same time, and controls the steering valve group and the lifting valve group to cut off the circuit with the steering cylinder, and connects the steering pump and lifting pump oil outlet with the lifting cylinder, so that all the hydraulic oil flows to the lifting cylinder to realize combined lifting.

[0016] As an improvement, the high-voltage box, BMS control box, traction converter, auxiliary converter and multi-in-one controller are installed in the electrical cabinet, which is located at the rear end of the walkway on the right side of the cab. There are five mounting points at the bottom of the electrical cabinet. Four of them are fixed to the walkway by bolts, and the rear mounting point near the cab side is fixed to the mounting seat on the walkway crossbeam by bolts. A vibration damping pad is provided between the mounting point and the mounting seat.

[0017] As an improvement, the electrical cabinet includes a frame structure and an outer skin. The outer skin is connected to the frame structure by screws. The outer skin corresponding to the position of the reactor in the auxiliary converter is a louvered outer skin, and the outer skin at the top is a sheet metal bending structure with reinforcing ribs welded.

[0018] As an improvement, the motor mounting seat includes an equipment end mounting seat fixed on both sides of the traction motor respectively and a frame end mounting seat fixed on the inner sides of the two frame longitudinal beams respectively. The equipment end mounting seat corresponds to the frame end mounting seat. The equipment end mounting seat includes a first horizontal plate and a first vertical plate, and the frame end mounting seat includes a second horizontal plate and a second vertical plate. The first vertical plate is connected to the traction motor by bolts, and the second vertical plate is connected to the frame longitudinal beam by bolts. A vibration damping component is provided between the first horizontal plate and the second horizontal plate.

[0019] As an improvement, the battery thermal management unit is arranged between the electrical cabinet and the cargo compartment, and the bottom of the battery thermal management unit is fixed to the cooling system mounting seat and the walkway crossbeam respectively.

[0020] As an improvement, the walkway crossbeam includes an integral crossbeam, fenders provided at the bottoms of both ends of the integral crossbeam, and beam mounting seats for connecting the frame provided on the left and right sides at the middle bottom of the integral crossbeam; a cab mounting seat is provided at the top of the left end of the integral crossbeam, an electrical cabinet mounting seat is provided at the middle top of the integral crossbeam, a valve group mounting seat is provided at the middle bottom of the integral crossbeam, a water-cooled unit mounting seat is provided at the top of the right end of the integral crossbeam, a walkway mounting seat is provided on the side of the right end of the integral crossbeam, and walkway mounting holes are provided on the walkway mounting seat and the integral crossbeam.

[0021] The beneficial effects brought by the present invention compared with the prior art are as follows:

[0022] 1. Solve the technical problem that a small-torque motor needs to increase torque through a transmission, and realize the direct drive technology of a large-torque motor. The application of a transmission will lead to problems such as low transmission efficiency, high failure rate and poor safety.

[0023] 2. Solve the problem of needing to add an eddy current retarder to supplement the braking ability, and realize the direct drive technology of a high-power motor and the large-rate battery technology. The application of an eddy current retarder will lead to a decrease in transmission efficiency and affect the recovery and utilization of energy.

[0024] 3. Solve the problem of heat waste caused by the relative independence of the thermal management system, implement multi-level thermal management technology, comprehensively manage the heat of the whole vehicle, and further improve the energy-saving effect of the vehicle;

[0025] 4. Solve the problem of a single drive source for the lifting and steering systems, implement the mutual redundancy technology of steering and lifting, and improve the adaptability of the vehicle under extreme working conditions. Description of the Drawings

[0026] Figure 1 It is a schematic diagram of a dump truck.

[0027] Figure 2 It is a schematic diagram of the frame of a dump truck.

[0028] Figure 3 It is a schematic diagram of the installation of a traction motor.

[0029] Figure 4 It is a schematic diagram of a walkway crossbeam.

[0030] Figure 5 It is a schematic diagram of the interior of an electrical cabinet.

[0031] Figure 6 It is a topology diagram of the configuration of a motor direct drive pure electric wide-body dump truck.

[0032] Figure 7 It is a topology diagram of the battery system.

[0033] Figure 8 It is a topology diagram of the drive system.

[0034] Figure 9 It is a working principle diagram of a multi-level thermal management system.

[0035] Figure 10 It is a working principle diagram of air conditioning and battery cooling.

[0036] Figure 11 It is a working principle diagram of air conditioning and battery heating.

[0037] Figure 12 It is a working principle diagram of air conditioning heating and battery cooling.

[0038] Figure 13 It is a control principle diagram of the hydraulic system.

[0039] Figure 14 It is a control flow chart of the rescue steering mode.

[0040] Figure 15 It is a control flow chart of the emergency lifting mode.

[0041] Figure 16 It is a control flow chart of the confluence lifting mode. Detailed Implementation Modes

[0042] The present invention will be further described below in conjunction with the accompanying drawings of the specification.

[0043] A wide-body dump truck directly driven by a high-voltage motor includes a non-powered chassis, a power supply system, a drive system, a multi-stage thermal management system, an auxiliary electrical system, a hydraulic system, a vehicle body, and a control system.

[0044] As Figure 7 、 8 shown, the function of the power supply system is to provide electrical energy for the electrical equipment of the whole vehicle. At the same time, it absorbs the electrical energy fed back during the electric braking of the whole vehicle. The power battery system includes a power battery box 7, a high-voltage box 14, a BMS control box 13, and a charging box 6. The power battery box 7 is respectively installed on both sides of the vehicle frame 8 through two battery brackets to make the force on the whole vehicle uniform. The power battery box 7 is equipped with power-type batteries. In this embodiment, a three-series and three-parallel circuit structure is adopted, with a rated charging rate of 3C and a rated discharge rate of up to 6C. The working voltage range is 710~980V. The 1000V high-voltage platform technology is adopted to effectively reduce the thermal loss of the conductive components while realizing fast charging. The main function of the high-voltage box 14 is high-voltage power distribution. It mainly concentrates the three battery branches on a unified busbar and outputs the current uniformly. The high-voltage box 14 has a pre-charge function and provides two outputs. The high-voltage box 14 is provided with a charging connector. The two charging lines are all connected to the high-voltage box 14 and are connected to the positive and negative main busbars of the power supply through the charging contactor; the high-voltage connectors outside the high-voltage box 14 adopt the form of quick-connect connectors. The BMS control box 13 communicates with the vehicle controller and the charging box 6 through the CAN bus. The vehicle controller reads the data of the BMS control box 13 through the CAN bus and displays the data on the dashboard. At the same time, intelligent charging control is realized through the communication between the BMS control box 13 and the charging box 6.

[0045] As Figures 1 to 3 shown, the drive system includes a traction motor 9, a traction converter 12, an auxiliary converter 10, and a motor controller. The traction motor 9 is installed between the two longitudinal beams 81 of the vehicle frame through a motor mounting seat, and the traction motor 9 has an included angle with the horizontal plane; the traction converter 12 and the auxiliary converter 10 are connected to the rear end of the pre-charge circuit of the high-voltage box 14. Among them, the auxiliary converter 10 provides a power distribution path for the traction converter 12; there are two charging sockets on the whole vehicle, with a maximum single-gun charging current of 300A and a maximum double-gun charging current of 600A. The charging time from SOC20% to 80% does not exceed 18 minutes; the charging box 6 is installed at the right step, located at the right front of the vehicle, and the ground clearance is about 1.35 meters, which is convenient for operation. As Figure 6As shown in the figure, under traction conditions, the power supply system distributes electrical energy to the auxiliary converter 10 and the traction converter 12 through the high-voltage box 14. Among them, the auxiliary converter 10 supplies power to the lifting motor and the multi-functional controller 11, and the multi-functional controller then drives the air compressor, the steering motor, the 24V battery, and the battery thermal management unit. The traction converter 12 controls the traction motor 9, and the traction motor 9 directly transmits power to the axle through the drive shaft. Under the condition of electric braking, the braking energy of the traction motor 9 is fed back to the power supply system through the traction converter 12. The auxiliary converter 10 includes a lifting control module and a DC / DC buck module, and mainly supplies power to the lifting motor and the multi-functional controller 11.

[0046] As Figure 3 shown, the motor mounting seat includes an equipment-end mounting seat 91 fixed on both sides of the traction motor 9 and a frame-end mounting seat 82 fixed on the inner sides of the two frame longitudinal beams 81 respectively. The equipment-end mounting seat 91 corresponds to the frame-end mounting seat 82. The equipment-end mounting seat 91 includes a first horizontal plate and a first vertical plate. The frame-end mounting seat 82 includes a second horizontal plate and a second vertical plate. The first vertical plate is connected to the traction motor 9 by bolts, and the second vertical plate is connected to the frame longitudinal beam by bolts. A vibration damping component is provided between the first horizontal plate and the second horizontal plate.

[0047] As Figure 5 shown, the high-voltage box 14, the BMS control box 13, the traction converter 12, the auxiliary converter 10, and the multi-functional controller 11 are installed in the electrical cabinet 5. The electrical cabinet 5 is located at the rear end of the walkway on the right side of the cab 2. There are five mounting points at the bottom of the electrical cabinet 5. Four of the mounting points are fixed to the walkway 3 by bolts, and the rear mounting point near the cab 2 side is fixed to the mounting seat of the walkway cross beam 31 by bolts. A vibration damping pad is provided between the mounting point and the mounting seat. The electrical cabinet 5 includes a frame structure and an outer skin. The outer skin is connected to the frame structure by screws. The outer skin corresponding to the reactor position in the auxiliary converter 10 is a louvered outer skin to meet the heat dissipation and ventilation requirements. The outer skin at the top is a sheet metal bending structure and is welded with reinforcing ribs to prevent the outer skin from being dented due to trampling. The outer skins are all connected to the frame structure by screws to facilitate the installation, maintenance, wiring, and piping of the equipment inside the electrical cabinet 5 bracket.

[0048] As Figure 4As shown in the figure, the platform crossbeam 31 includes an integral crossbeam 311, mudguards 312 provided at the bottoms of both ends of the integral crossbeam 311, and crossbeam mounting seats 313 provided on the left and right sides at the middle bottom of the integral crossbeam 311 for connecting the vehicle frame; a cab mounting seat 314 is provided at the top of the left end of the integral crossbeam 311, an electrical cabinet mounting seat 315 is provided at the middle top of the integral crossbeam 311, a valve group mounting seat 316 is provided at the middle bottom of the integral crossbeam 311, a water-cooled unit mounting seat 317 is provided at the top of the right end of the integral crossbeam 311, a platform mounting seat 318 is provided on the side of the right end of the integral crossbeam 311, and platform mounting holes are provided on the platform mounting seat 318 and the integral crossbeam 311.

[0049] As Figure 9 shown, the multi-stage thermal management system integrates the battery thermal management unit, ATS and air conditioning system, and integrates the cooling or heating requirements of key heat sources such as the battery pack, electric drive system and air conditioning system into a unified and efficient management system. As Figure 10 shown, the air conditioning refrigeration and battery refrigeration share a compressor and a condenser. After the refrigeration circuit passes through the condenser, it is divided into two branches. The cab air conditioning branch is controlled by a combination valve, and the battery refrigeration branch is controlled by an electronically controlled expansion valve. The battery water circulation circuit exchanges heat with the battery refrigeration branch through the first heat exchanger; when the third water pump works and the water valve closes the outlet to the second low-temperature radiator, the heat of the coolant in the battery cooling circuit is transferred to the refrigerant in the refrigeration branch through the second heat exchanger and taken away, so that the temperature of the coolant is reduced to cool the battery. Figure 11 shown, when the battery and the air conditioning need to be heated, the coolant flows through the traction motor 9 and the PTC heater in sequence for heating, and the heated coolant is proportionally distributed to the cab air conditioning and the battery heating branch through the water valve. The battery heating branch exchanges heat with the battery water circulation circuit through the second heat exchanger; at this time, the first water valve controls to close the outlet to the first low-temperature radiator, the third water valve controls to close the outlet to the second low-temperature radiator, the first water pump and the third water pump work, and the second water pump does not work. Figure 12 shown, when the battery needs to be refrigerated and the cab air conditioning needs to be heated, the coolant flows through the traction motor 9, the third heat exchanger and the PTC heater in sequence, and the heated coolant is distributed to the cab air conditioning through the water valve. The compressor refrigerant passes through the third heat exchanger, the condenser, the electronically controlled expansion valve and the first heat exchanger in sequence; at this time, the first water valve controls to close the outlet to the first low-temperature radiator, the second water valve controls to close the outlet to the second heat exchanger, the first water pump and the third water pump work, and the second water pump does not work. In the above water circulation circuit, a water pump is used as the power for the coolant to flow; the first heat exchanger and the third heat exchanger are plate heat exchangers, and the second heat exchanger is a water-water heat exchanger; the evaporator core of the cab air conditioning cooperates with the refrigerant to blow out cold air, and the warm air core of the cab air conditioning cooperates with the heated coolant to blow out hot air.

[0050] As Figure 13 shown, the hydraulic system includes a controller, a lifting motor, a lifting pump, a lifting cylinder, a lifting valve group, a steering motor, a steering pump, a steering cylinder, and a steering valve group. As Figure 14 shown, when the steering motor or the steering pump fails and steering is required, a rescue instruction is sent to the controller by pressing the rescue steering switch. The controller controls the lifting motor to start and controls the lifting valve group to cut off the circuit between the lifting pump and the lifting cylinder, and connect the oil outlet of the lifting pump to the steering cylinder, so that the hydraulic oil pumped by the lifting pump can flow into the steering system to achieve steering. As Figure 15 shown, when the lifting motor or the lifting pump fails and lifting is required, an instruction is sent to the controller by pressing the emergency lifting switch. The controller controls the steering motor to start and controls the steering valve group to cut off the circuit between the steering pump and the steering cylinder, and connect the oil outlet of the steering pump to the lifting cylinder, so that the hydraulic oil pumped by the steering pump can flow into the lifting system to achieve emergency lifting. As Figure 16 shown, during normal lifting, the controller controls the steering motor and the lifting motor to work simultaneously, and controls the steering valve group and the lifting valve group to cut off the circuit with the steering cylinder, and connect the oil outlets of the steering pump and the lifting pump to the lifting cylinder, so that all the hydraulic oil flows to the lifting cylinder to achieve combined flow lifting.

Claims

1. A wide-body dump truck directly driven by a high-voltage motor, comprising an unpowered chassis, a power supply system, a drive system, a multi-stage thermal management system, an auxiliary electrical system, a hydraulic system, a body, and a control system, characterized by: The power supply system includes a power battery box, a high-voltage box, a BMS control box and a charging box; the power battery box is mounted on both sides of the vehicle frame via two battery brackets; the high-voltage box concentrates all battery branches on a unified busbar to output current, and the high-voltage box is provided with a charging connector; the BMS control box communicates with the vehicle controller and the charging box via the CAN bus, and the vehicle controller reads the BMS control box data via the CAN bus and displays the data on the instrument panel. Charging control is also achieved through communication between the BMS control box and the charging box. The drive system includes a traction motor, a traction inverter, an auxiliary inverter and a motor controller; the traction motor is installed between the two longitudinal beams of the frame through a motor mounting seat, and the traction motor is arranged at an angle with the horizontal plane; the traction inverter and the auxiliary inverter are connected to the rear end of the high-voltage box pre-charging circuit, wherein the auxiliary inverter provides a power distribution line for the traction inverter; under traction conditions, the power supply system distributes electric energy to the auxiliary inverter and the traction inverter through the high-voltage box, wherein the auxiliary inverter supplies power to the lifting motor and the all-in-one controller, and the all-in-one controller then drives the air compressor, the steering motor, the 24V battery and the battery thermal management unit, the traction inverter controls the traction motor, and the traction motor directly transmits power to the axle through the drive shaft; under electric braking conditions, the braking energy of the traction motor is fed back to the power supply system through the traction inverter; The multi-stage thermal management system includes a battery thermal management unit, an ATS and an air conditioning system; the air conditioning refrigeration and battery refrigeration share a compressor and condenser, and the refrigeration circuit is divided into two branches after passing through the condenser. The cab air conditioning branch is controlled by a combination valve, and the battery refrigeration branch is controlled by an electronically controlled expansion valve. The battery water circulation circuit and the battery refrigeration branch exchange heat through a first heat exchanger; when the battery and air conditioning need to be heated, the coolant flows through the traction motor and the PTC heater in sequence for heating. The heated coolant is proportionally distributed to the cab air conditioning and battery heating branches through a water valve, and the battery heating branch and the battery water circulation circuit exchange heat through a second heat exchanger; when the battery needs to be cooled and the cab air conditioning needs to be heated, the coolant flows through the traction motor, the third heat exchanger and the PTC heater in sequence. The heated coolant is distributed to the cab air conditioning through a water valve, and the compressor refrigerant passes through the third heat exchanger, the condenser, the electronically controlled expansion valve, and the first heat exchanger in sequence; The hydraulic system includes a controller, a lifting motor, a lifting pump, a lifting cylinder, a lifting valve group, a steering motor, a steering pump, a steering cylinder and a steering valve group; when the steering motor or the steering pump fails and steering is required, a rescue command is sent to the controller by pressing the rescue steering switch, and the controller controls the lifting motor to start and controls the lifting valve group to cut off the circuit between the lifting pump and the lifting cylinder, connecting the lifting pump oil outlet and the steering cylinder so that the hydraulic oil pumped out by the lifting pump can flow into the steering system to achieve steering; when the lifting motor or the steering pump fails and lifting is required When the emergency lift is in operation, the controller sends a command to the controller by pressing the emergency lift switch. The controller controls the steering motor to start, and controls the steering valve group to cut off the circuit between the steering pump and the steering cylinder, and connects the steering pump oil outlet with the lifting cylinder, so that the hydraulic oil pumped out by the steering pump can flow into the lifting system to realize emergency lifting. During normal lifting, the controller controls the steering motor and the lifting motor to work at the same time, and controls the steering valve group and the lifting valve group to cut off the circuit with the steering cylinder, and connects the steering pump and lifting pump oil outlet with the lifting cylinder, so that all the hydraulic oil flows to the lifting cylinder to realize combined lifting.

2. The wide-body dump truck directly driven by a high-voltage motor according to claim 1, wherein: The high-voltage box, BMS control box, traction inverter, auxiliary inverter and all-in-one controller are installed in the electrical cabinet, which is located at the rear end of the walkway on the right side of the cab. Five mounting points are provided at the bottom of the electrical cabinet, four of which are fixed to the walkway by bolts. The rear mounting point close to the cab side is fixed to the mounting seat of the walkway crossbeam by bolts, and a vibration damping pad is provided between the mounting point and the mounting seat.

3. The wide-body dump truck directly driven by a high-voltage motor according to claim 2, characterized in that: The electrical cabinet includes a frame structure and an outer skin, which is connected to the frame structure by screws. The outer skin corresponding to the position of the reactor in the auxiliary converter is a louver outer skin, and the outer skin on the top is a sheet metal bending structure with reinforced ribs welded thereon.

4. A wide-body dump truck directly driven by a high-voltage motor according to claim 1, characterized in that: The motor mounting seat includes equipment end mounting seats respectively fixed on both sides of the traction motor and frame end mounting seats respectively fixed on the inner sides of the two frame longitudinal beams. The equipment end mounting seat corresponds to the frame end mounting seat. The equipment end mounting seat includes a first horizontal plate and a first vertical plate. The frame end mounting seat includes a second horizontal plate and a second vertical plate. The first vertical plate is connected to the traction motor by bolts, and the second vertical plate is connected to the frame longitudinal beam by bolts. A vibration damping assembly is provided between the first horizontal plate and the second horizontal plate.

5. The wide-body dump truck directly driven by a high-voltage motor according to claim 2, wherein: The battery thermal management unit is arranged between the electrical cabinet and the cargo compartment, and the bottom of the battery thermal management unit is respectively fixed on the cooling system mounting seat and the platform crossbeam.

6. The wide-body dump truck directly driven by a high-voltage motor according to claim 5, characterized in that: The walkway beam includes an integral crossbeam, mudguards arranged at the bottom of both ends of the integral crossbeam, and crossbeam mounting seats for connecting to the frame arranged on the left and right sides of the middle bottom of the integral crossbeam; a cab mounting seat is provided at the top of the left end of the integral crossbeam, an electrical cabinet mounting seat is provided at the middle top of the integral crossbeam, a valve group mounting seat is provided at the middle bottom of the integral crossbeam, a water-cooling unit mounting seat is provided at the top of the right end of the integral crossbeam, a walkway mounting seat is provided on the right end side of the integral crossbeam, and walkway mounting holes are provided on the walkway mounting seat and the integral crossbeam.

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