In-wheel motor low-pressure water cooling and energy recovery system and method

Abstract

The application discloses a kind of low-pressure water-cooled energy recovery system and method of in-wheel motor.The method of the application comprises: vacuum pump and pressure difference valve divide water channel into low-pressure water channel and standard pressure water channel, and the temperature in standard pressure water channel is normal;monitoring device monitors the temperature of in-wheel motor in real time, and transmits signal to vacuum pump according to the maximum temperature value;vacuum pump controls the pressure in low-pressure water channel according to the signal and controls the opening and closing of pressure difference valve;the pressure in low-pressure water channel is low, and the boiling point of water is low;when pressure difference valve is opened, cooling water spirals into the inside of cooling shaft, covers cooling shaft to the greatest extent, and cooling water vaporization absorbs heat;cooling water enters standard pressure water channel, cooling water liquefies and releases heat, and heat is converted into electric energy by heat energy generator and provided to automobile battery pack.The application can realize the temperature reduction of motor by using low-pressure water cooling, and recycle the heat generated during the operation and braking process of motor;in the process of temperature reduction and heat recycling, the temperature of motor can be accurately controlled.

Description

Technical Field

[0001] This invention belongs to the field of hub motor technology, specifically relating to a low-pressure water cooling and energy recovery system and method for hub motors. Background Technology

[0002] Vehicle pollution has always been one of the main sources of environmental pollution. Against the backdrop of the energy crisis and increasingly serious environmental pollution, it is an inevitable trend for new energy vehicles that use clean and renewable energy as their energy source to replace traditional vehicles that use fossil fuels.

[0003] Among the various development directions of new energy vehicles, in-wheel motors are very suitable for electric vehicles due to their advantages such as compact structure, high transmission efficiency, and flexible control and steering, thus becoming an important development direction. However, due to the working environment of in-wheel motors, good sealing is required, which makes heat dissipation difficult. Excessive operating temperature of the motor can cause demagnetization of permanent magnets and aging of insulation layers, seriously affecting its performance and lifespan. Therefore, motor heat dissipation has become one of the biggest challenges in the practical application of in-wheel motors.

[0004] At present, hub motors mainly use three cooling methods: air cooling, oil cooling, and water cooling. However, these traditional cooling methods cannot bring the motor down to the most suitable operating temperature. Moreover, in order to enhance the cooling effect, complex cooling channels are often required, which increases the weight and space occupied by the hub motor, as well as the design and manufacturing costs, which is not conducive to the development of hub motors.

[0005] Traditional water-cooled and oil-cooled cooling systems require the coolant to be cooled after absorbing the heat generated by the motor in order to complete a full cycle. This not only wastes thermal energy but also consumes energy to dissipate heat from the coolant, which has a significant impact on the driving range of electric vehicles.

[0006] In existing technical solutions, such as the stator water-cooling structure of a hub motor disclosed in application publication number CN 108599411 A, there are stator teeth and stator yoke. The stator yoke has several through holes in the same direction as the stator axis. Cooling water pipes are installed in the through holes. One end of the cooling water pipe has an inlet port and the other end has an outlet port. The cooling water pipes and the through holes form a U-shaped connection. The inlet and outlet ports of the cooling water pipes extend out and are located on the same outer side of the stator. The cooling water pipes are tightly fixed to the through holes in the stator yoke. The cooling water pipes pass through each through hole in a U-shape. The cooling water pipes are tightly assembled with the stator by epoxy potting, which makes the heat dissipation of the hub motor uniform. However, after absorbing the heat of the motor, this water-cooling structure does not utilize this heat. Energy is still needed to dissipate the heat of the cooling water, which has a significant impact on the driving range of electric vehicles.

[0007] For example, in the liquid-cooled hub motor cooling thermoelectric generator and its working method disclosed in application publication number CN 108599621 A, the hub motor is cooled by a combination of coolant spraying and a circulating oil circuit within the motor housing. The oil tank has a metal shell, and the thermoelectric generator is pressed onto the grooved metal shell of the oil tank, with a metal plate pressed on top of the thermoelectric generator. The outer shell of the oil tank serves as the hot end of the thermoelectric generator, while the metal plate in contact with the outside cold air serves as the cold end. However, the coolant is sprayed directly onto the heating element, and after absorbing heat, the coolant returns to the oil tank. This cooling recovery method cannot accurately regulate the temperature of the hub motor itself, and the direct spraying of coolant results in significant waste and high economic costs.

[0008] To address the above technical problems, this invention proposes a low-pressure water cooling and energy recovery system and method for hub motors. Summary of the Invention

[0009] The purpose of this invention is to overcome the shortcomings of the prior art and propose a low-pressure water cooling energy recovery system and method for hub motors. This system can use low-pressure water cooling to cool the motor and recover the heat generated during motor operation and braking. It achieves precise control of motor temperature during the cooling and heat recovery process, improves energy utilization, reduces losses, and has a compact structure with a small footprint.

[0010] To achieve the above objectives, the present invention proposes the following technical solution: A low-pressure water-cooled energy recovery system for a hub motor includes a hub motor body and a low-pressure water-cooled and energy recovery system. The low-pressure water-cooled and energy recovery system dissipates heat from the hub motor body and recovers and reuses the absorbed heat.

[0011] The hub motor body includes a tire, hub, motor housing, hub bearing, motor rotor, motor stator, cooling shaft, protective cover, brake pads, brake calipers, bearings, and end caps; The tire is fitted onto the wheel hub, the motor housing is fixed to the wheel hub by bolts on the wheel hub bearing, the motor rotor is welded inside the motor housing, and the brake pads and end caps are fixed to the motor housing by bolts; one end of the cooling shaft is mounted on the wheel hub by a wheel hub bearing, and the other end of the cooling shaft is mounted on the end cap by a bearing. The cooling shaft is equipped with a spiral channel inside, which covers the interior of the cooling shaft to the greatest extent to ensure the cooling effect; the other end of the cooling shaft is equipped with a cooling water inlet channel and a cooling water outlet channel on both sides, and the spiral channel is connected to the cooling water inlet channel and the cooling water outlet channel respectively; The motor stator, protective cover, and brake caliper are respectively connected to the cooling shaft by bolts.

[0012] The low-pressure water cooling and energy recovery system includes a low-pressure water channel, a standard pressure water channel, a thermal generator, a water tank, a differential pressure valve, a monitor, and a vacuum pump. The outlet end of the low-pressure water channel is connected to the vacuum pump, and the inlet end of the low-pressure water channel is connected to the differential pressure valve; the low-pressure water channel is disconnected in the middle and connected to the cooling water inlet channel and the cooling water outlet channel on the cooling shaft respectively; the pressure in the low-pressure water channel is lower than the standard pressure, and the cooling water in the low-pressure water channel has a low boiling point and is easy to vaporize, thereby absorbing heat and cooling the cooling shaft. The inlet of the standard pressure water channel is connected to a vacuum pump, and the outlet of the standard pressure water channel is connected to a differential pressure valve; the pressure inside the standard pressure water channel is standard atmospheric pressure, and the boiling point of water is at the normal value under standard atmospheric pressure.

[0013] The thermal generator is located at the inlet of the standard pressure water channel and is also connected to the vacuum pump. The water tank is located in the middle of the standard pressure water channel, which is disconnected from the water tank in the middle; the water tank contains cooling water. One end of the differential pressure valve is connected to the inlet end of the low-pressure waterway, and the other end of the differential pressure valve is connected to the outlet end of the standard pressure waterway. The differential pressure valve is equipped with a rated pressure difference. When the pressure difference between the standard pressure channel and the low pressure channel reaches the rated pressure difference, the differential pressure valve is opened. When the pressure difference between the standard pressure channel and the low pressure channel is lower than the rated pressure difference, the differential pressure valve is closed.

[0014] The monitor is equipped with temperature sensors at various points on the hub motor. The monitor is connected to the vacuum pump via wires. The monitor sends commands to the vacuum pump based on the temperature signals transmitted by the temperature sensors to control the vacuum pump. By adjusting the pressure in the low-pressure water channel through the vacuum pump, the water volume and flow rate in the low-pressure water channel are changed, thereby adjusting the temperature of the hub motor, i.e., cooling it down, and keeping the temperature of the hub motor within a reasonable range. It cools down the motor down in a timely manner while recovering heat. The vacuum pump adjusts the pressure in the low-pressure waterway according to the instructions of the monitor; The vacuum pump is set with three gears for hub motors at different temperatures, corresponding to different pressure values ​​in the low-pressure water channel. In the first gear, the differential pressure valve is closed, and in the second and third gears, the differential pressure valve is open. The volume and flow rate of cooling water in the low-pressure water channel are different in different gears. In the third gear, the vacuum suction is increased, and the volume and flow rate of cooling water are increased. The higher the temperature of the hub motor, the higher the setting of the vacuum pump, and the greater the water volume and flow rate in the low-pressure water channel. This results in a better cooling effect and faster cooling speed for the hub motor, thereby controlling the temperature of the hub motor within a reasonable range and achieving precise temperature control.

[0015] Preferably, in the first gear, the vacuum pump operates, resulting in low pressure in the low-pressure water channel, but the pressure difference between the low-pressure water channel and the standard pressure water channel is lower than the rated pressure difference of the differential pressure valve; in the second gear, the vacuum pump continues to operate, causing the pressure in the low-pressure water channel to continue to decrease, and the pressure difference between the low-pressure water channel and the standard pressure water channel equals the rated pressure difference of the differential pressure valve, so the differential pressure valve opens, allowing cooling water to slowly enter the low-pressure water channel to begin vaporization and cooling; in the third gear, the vacuum pump continues to operate, and due to the increased suction of the vacuum pump, the flow rate and volume of the cooling water increase, resulting in rapid vaporization and cooling. Preferably, the protective cover is placed between the motor stator and the brake caliper to isolate the two, thereby achieving effective protection for the hub motor.

[0016] Preferably, the cooling water inlet channel and cooling water outlet channel on the cooling shaft are connected to the low-pressure water channel by screws, which facilitates installation and replacement.

[0017] Preferably, the low-pressure water channel is connected to the vacuum pump and differential pressure valve by welding, which results in good structural density, high airtightness, strong overall integrity, high strength, and strong pressure resistance.

[0018] Preferably, the vacuum pump is connected to the thermal generator, the thermal generator to the standard pressure water channel, the water tank to the standard pressure water channel, and the differential pressure valve to the standard pressure water channel by threaded connection, which facilitates installation and replacement.

[0019] Preferably, the rated differential pressure of the differential pressure valve is 0.097 MPa, and the standard pressure is 0.1 MPa. When the pressure of the low-pressure water channel is 0.003 MPa, the differential pressure valve can be opened. Under this pressure, the boiling point of water decreases to 24.079°C. If the temperature of the hub motor reaches the boiling point of water, the water will change and vaporize, absorbing heat and removing the heat from the hub motor, thereby reducing the temperature of the hub motor.

[0020] Another objective of this invention is to disclose a method for low-pressure water-cooled energy recovery in a hub motor, characterized by comprising the following parts: ① The vacuum pump and differential pressure valve divide the water channel into a low-pressure water channel and a standard pressure water channel. The standard pressure water channel is at room temperature and the boiling point of the cooling water is normal. ② The monitor monitors the temperature of the hub motor in real time and sends a signal to the vacuum pump based on the maximum temperature value. The vacuum pump adjusts the pressure in the low-pressure water channel according to the signal, and then controls the opening and closing of the differential pressure valve. ③ The pressure inside the low-pressure water channel is low, the boiling point of water is low, and when the differential pressure valve is opened, the cooling water spirals into the interior of the cooling shaft, covering the cooling shaft to the maximum extent, and the cooling water vaporizes and absorbs heat. ④ When the cooling water enters the standard pressure water channel, the boiling point returns to normal, the cooling water liquefies and releases heat, and the heat is converted into electrical energy by the heat generator to supply the car battery pack.

[0021] Preferably, the monitor monitors the maximum temperature of the wheel hub motor based on various temperature sensors. When the maximum temperature is below 45°C, the monitor controls the vacuum pump to operate in the first gear. When the maximum temperature reaches 45°C, the monitor controls the vacuum pump to operate in the second gear. When the maximum temperature drops to 35°C, the monitor controls the vacuum pump to return to the first gear. When the maximum temperature reaches 45°C and continues to rise to 50°C, the monitor controls the vacuum pump to operate in the third gear, thereby controlling the overall temperature of the wheel hub motor to be below 35°C.

[0022] The entire waterway is divided into a low-pressure waterway and a standard pressure waterway by a differential pressure valve and a vacuum pump. Its working waterway is the low-pressure waterway. In the low-pressure waterway, the pressure is reduced, which lowers the boiling point of the water. The water vaporization absorbs the heat generated during the operation and braking of the hub motor.

[0023] The monitor sends different commands to the vacuum pump based on the highest temperature signal transmitted by the temperature sensor. This causes the vacuum pump to adjust its speed according to the temperature of the hub motor. If the temperature is high, the speed is increased to reduce the pressure in the low-pressure water channel until the pressure reaches the value that allows the differential pressure valve to open. Cooling water then slowly enters the low-pressure water channel to begin vaporization and cooling. If the temperature continues to rise, the speed is increased again to further reduce the pressure in the low-pressure water channel, increasing the flow rate of cooling water for rapid cooling.

[0024] If the temperature is normal, lower the setting. The pressure in the low-pressure water channel will remain at the pressure value that prevents the differential pressure valve from opening, and cooling is not required.

[0025] The differential pressure valve is a widely used component in the prior art. When the pressure difference between the inlet and outlet reaches the rated pressure difference, the differential pressure valve can be opened. If it is lower than the rated pressure difference, the differential pressure valve is in the closed state.

[0026] The vacuum pump controls the opening and closing of the differential pressure valve by adjusting the pressure in the low-pressure water channel. In the first gear, the pressure difference between the low-pressure water channel and the standard pressure water channel is lower than the pressure difference required to open the differential pressure valve. In the second gear, the pressure difference between the low-pressure water channel and the standard pressure water channel is exactly equal to the rated pressure difference, which is just enough to open the differential pressure valve. The cooling water flow rate is slower, and the cooling water enters the low-pressure water channel from the standard pressure water channel, reducing the pressure and thus lowering the boiling point of the water. The water vaporization absorbs heat and cools the hub motor cooling shaft. In the third gear, the vacuum pump's suction force increases, causing more and faster cooling water to flow from the standard pressure water channel into the low-pressure water channel, accelerating the cooling water flow rate, increasing the cooling water volume, and thus enhancing the cooling effect on the cooling shaft, reducing the temperature of the hub motor, protecting the hub motor's performance, and extending its service life.

[0027] After vaporization, the water vapor enters the standard pressure water channel through a vacuum pump. Inside the standard pressure water channel, it is at room temperature, and the boiling point returns to normal. The water vapor then liquefies. The large amount of heat released during the liquefaction process supplies the heat generator, which uses this heat energy to generate electricity, which then replenishes the car's battery pack.

[0028] The water tank is located on the standard pressure water channel to store cooling water. After the water vapor liquefies, it will enter the water tank. When the pressure difference between the standard pressure water channel and the low pressure water channel reaches the rated pressure difference of the differential pressure valve, the water in the water tank enters the low pressure water channel through the differential pressure valve, thus forming a cooling cycle for the hub motor.

[0029] The specific steps are as follows: After the electric vehicle starts, the monitor, vacuum pump and thermal generator start up. The monitor monitors the maximum temperature of the motor through temperature sensors distributed throughout the motor. When the maximum temperature is below 45°C, the monitor controls the vacuum pump to enter the first gear. The pressure in the low-pressure water channel decreases, but at this time the pressure difference is insufficient to open the differential pressure valve, and no cooling operation is performed.

[0030] When the motor's maximum temperature reaches 45℃, the monitor controls the vacuum pump to enter the second gear. The pressure in the low-pressure water channel continues to decrease. When the pressure difference equals the rated pressure difference of the differential valve, the differential valve can just open. At this time, cooling water begins to slowly enter. Since the temperature in the low-pressure water channel is much higher than the boiling point of water at this pressure, the cooling water begins to vaporize and cool down. When the motor's maximum temperature drops to 35℃, the monitor controls the vacuum pump to return to the first gear, and cooling is paused.

[0031] If the motor's maximum temperature continues to rise to 50°C in the second gear, the monitor controls the vacuum pump to enter the third gear. At this time, the vacuum pump continues to run, the suction force increases, and more cooling water flows into the low-pressure water channel more quickly, thereby achieving rapid cooling.

[0032] Since the temperature of the hub motor corresponding to the second gear is higher than the boiling point of the water in the low-pressure water channel, the cooling water in the low-pressure water channel can be mostly vaporized during the cooling process in the second gear, which is beneficial to the subsequent heat energy recovery and utilization.

[0033] During the second and third gear operation, the hub motor begins to cool down. During this process, water vapor simultaneously enters the standard pressure water channel. As the pressure in the standard pressure water channel returns to the standard value, the boiling point of water returns to normal. Subsequently, the water vapor enters the heat generator and quickly liquefies, releasing a large amount of heat. The heat generator uses this heat to convert it into electricity to provide power to the electric vehicle's battery pack, thereby realizing the recovery and utilization of heat generated during motor operation and braking, improving energy utilization efficiency and reducing losses.

[0034] The vacuum pump and thermal generator involved in this invention are both commonly used devices in the prior art and can be used directly.

[0035] The beneficial effects of this invention are as follows: This invention integrates the cooling channel and the cooling shaft into one by setting a spiral channel inside the cooling shaft and covering the cooling shaft to the maximum extent, saving space occupied by components and not affecting the compact structure of the hub motor.

[0036] In this invention, the entire water channel is divided into a low-pressure water channel and a standard pressure water channel by a differential pressure valve and a vacuum pump. The low-pressure water channel is the working area. By operating the vacuum pump, the pressure in the low-pressure water channel is reduced, thereby lowering the boiling point of the water. The water vaporization absorbs the heat generated during the operation and braking of the motor. Furthermore, by switching the three speeds of the vacuum pump in a timely manner, the corresponding temperature drop rate is changed, thereby achieving timely cooling of the hub motor temperature and achieving a better cooling effect.

[0037] In this invention, a thermal generator is installed at the inlet of a standard pressure water channel. After the water vapor enters the standard pressure water channel, the pressure returns to normal and the boiling point increases accordingly, causing the water vapor to liquefy. The thermal generator absorbs the heat generated by the liquefaction of the water vapor to generate electricity, effectively reducing energy waste and helping to increase the driving range of electric vehicles.

[0038] This invention monitors the overall temperature of the hub motor in real time using a monitor, and controls the vacuum pump based on the highest temperature. Through the cooperation of the vacuum pump and the differential pressure valve, the hub motor is cooled down at different temperatures, thereby accurately controlling the temperature of the hub motor and keeping it within a reasonable range, thus extending the life of the hub motor.

[0039] By adopting the above solution, the present invention can cool the motor by using low-pressure water cooling, and at the same time recover the heat generated during the operation and braking of the motor. In the process of cooling and recovering heat, the motor temperature can be accurately controlled, improving energy utilization, reducing losses, and the structure is compact and occupies little space. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This is a cross-sectional view of the hub motor body of the present invention.

[0042] Figure 2This is an exploded view of the hub motor body of the present invention.

[0043] Figure 3 This is a schematic diagram of the low-pressure water cooling and energy recovery system of the present invention.

[0044] Figure 4 This is a schematic cross-sectional view of the cooling shaft in this invention.

[0045] In the diagram, 1-Tire; 2-Wheel hub; 3-Motor housing; 4-Wheel hub bearing; 5-Motor stator; 6-Air gap; 7-Motor rotor; 8-Gasket; 9-Brake pad; 10-Brake caliper; 11-End cover; 13-Bearing; 14-Cooling shaft; 15-Protective cover; 121-Low-pressure water channel; 122-Vacuum pump; 123-Thermal generator; 124-Standard pressure water channel; 125-Water tank; 126-Differential pressure valve; 127-Monitor; 14-Cooling shaft, 141-Helical channel, 142-Cooling water inlet channel, 143-Cooling water outlet channel. Implementation

[0046] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0047] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0048] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0049] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0050] like Figures 1-3 As shown, a low-pressure water-cooled energy recovery system for a hub motor includes a hub motor body and a low-pressure water-cooled and energy recovery system. The low-pressure water-cooled and energy recovery system dissipates heat from the hub motor body and recovers and reuses the absorbed heat.

[0051] The hub motor body includes a tire 1, a hub 2, a motor housing 3, a hub bearing 4, a motor rotor 7, a motor stator 5, a cooling shaft 14, a protective cover 15, a brake pad 9, a brake caliper 10, a bearing 13, and an end cover 11. The tire 1 is fitted onto the hub 2, the motor housing 3 is fixed to the hub 2 by bolts on the hub bearing 4, the motor rotor 7 is welded inside the motor housing 3, and the brake pad 9 and end cover 11 are fixed to the motor housing 3 by bolts; one end of the cooling shaft 14 is mounted on the hub 2 via the hub bearing 4, and the other end of the cooling shaft 14 is mounted on the end cover 11 via the bearing 13. The cooling shaft 14 is provided with a spiral channel 141 inside, which covers the interior of the cooling shaft 14 to the maximum extent to ensure the cooling effect; the other end of the cooling shaft 14 is provided with a cooling water inlet channel 142 and a cooling water outlet channel 143 on both sides, and the spiral channel 141 is connected to the cooling water inlet channel 142 and the cooling water outlet channel 143 respectively. The motor stator 5, protective cover 15, and brake caliper 10 are respectively connected to the cooling shaft 14 by bolts.

[0052] The low-pressure water cooling and energy recovery system includes a low-pressure water channel 121, a standard pressure water channel 124, a thermal generator 123, a water tank 125, a differential pressure valve 126, a monitor 127, and a vacuum pump 122. The outlet end of the low-pressure water channel 121 is connected to the vacuum pump 122, and the inlet end of the low-pressure water channel 121 is connected to the differential pressure valve 126. The low-pressure water channel 121 is disconnected in the middle and connected to the cooling water inlet channel 142 and the cooling water outlet channel 143 on the cooling shaft 14. The pressure inside the low-pressure water channel 121 is lower than the standard pressure, and the cooling water inside the low-pressure water channel 121 has a low boiling point and is easy to vaporize, thereby absorbing heat and cooling the cooling shaft 14. The inlet end of the standard pressure water channel 124 is connected to the vacuum pump 122, and the outlet end of the standard pressure water channel 124 is connected to the differential pressure valve 126; the pressure inside the standard pressure water channel 124 is standard atmospheric pressure, and the boiling point of water is at the normal value under standard atmospheric pressure.

[0053] The thermal generator 123 is located at the inlet end of the standard pressure water channel 124, and the thermal generator 123 is also connected to the vacuum pump 122. The water tank 125 is located in the middle of the standard pressure water channel 124, which is disconnected in the middle from the water tank 125; the water tank 125 contains cooling water. One end of the differential pressure valve 126 is connected to the inlet end of the low-pressure water channel 121, and the other end of the differential pressure valve 126 is connected to the outlet end of the standard pressure water channel 124. The differential pressure valve 126 is equipped with a rated pressure difference. When the pressure difference between the standard pressure channel 124 and the low pressure channel 121 reaches the rated pressure difference, the differential pressure valve 126 is opened. When the pressure difference between the standard pressure channel 124 and the low pressure channel 121 is lower than the rated pressure difference, the differential pressure valve 126 is closed.

[0054] The monitor 127 is equipped with temperature sensors at various points on the hub motor. The monitor 127 is connected to the vacuum pump 122 via wires. The monitor 127 transmits commands to the vacuum pump 122 based on the temperature signals transmitted by the temperature sensors, thereby controlling the vacuum pump 122. By adjusting the pressure in the low-pressure water channel 121 through the vacuum pump 122, the water volume and flow rate in the low-pressure water channel 121 are changed, thereby adjusting the temperature of the hub motor, i.e., cooling it down, and controlling the temperature of the hub motor within a reasonable range, while recovering heat in a timely manner. The vacuum pump 122 adjusts the pressure in the low-pressure water channel 121 according to the instructions of the monitor 127; The vacuum pump 122 is set with three gears for the hub motor at different temperatures, corresponding to different pressure values ​​in the low-pressure water channel 121. In the first gear, the differential pressure valve 126 is in the closed state, and in the second and third gears, the differential pressure valve 126 is in the open state. The amount and flow rate of cooling water in the low-pressure water channel 121 are different in different gears. The higher the temperature of the hub motor, the higher the setting of the vacuum pump 122, and the greater the water volume and flow rate in the low-pressure water channel 121. This results in a better cooling effect and faster cooling speed for the hub motor, thereby controlling the temperature of the hub motor within a reasonable range and achieving precise control of the hub motor temperature.

[0055] A method for low-pressure water-cooled energy recovery of a hub motor, characterized by comprising the following parts: ① The vacuum pump 122 and the differential pressure valve 126 divide the water channel into a low-pressure water channel 121 and a standard pressure water channel 124. The standard pressure water channel 124 is at room temperature and the boiling point of the cooling water is normal. ② The monitor 127 monitors the temperature of the hub motor in real time and transmits a signal to the vacuum pump 122 according to the maximum temperature value. The vacuum pump 122 adjusts the pressure in the low-pressure water channel 121 according to the signal, and then controls the opening and closing of the differential pressure valve 126. ③ The pressure inside the low-pressure water channel 121 is low, the boiling point of water is low, and when the differential pressure valve 126 is opened, the cooling water spirals into the interior of the cooling shaft 14, covering the cooling shaft 14 to the maximum extent, and the cooling water vaporizes and absorbs heat. ④ Cooling water enters the standard pressure water channel 124, the boiling point returns to normal, the cooling water liquefies and releases heat, and the heat is converted into electrical energy by the heat generator 123 to provide to the car battery pack.

[0056] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A low-pressure water-cooled energy recovery system for a hub motor, comprising a hub motor body, the hub motor body including a tire, a hub, a motor housing, a hub bearing, a motor rotor, a motor stator, a cooling shaft, a protective cover, brake pads, a brake caliper, bearings, and an end cover; the tire is fitted onto the hub; the motor housing is fixed to the hub by bolts on the hub bearing; the motor rotor is welded inside the motor housing; the brake pads and end cover are fixed to the motor housing by bolts; one end of the cooling shaft is mounted on the hub via the hub bearing, and the other end of the cooling shaft is mounted on the end cover via a bearing; the motor stator, the protective cover, and the brake caliper are respectively connected to the cooling shaft by bolts; characterized in that: The cooling shaft has a spiral channel inside, and cooling water inlet channel and cooling water outlet channel are provided on both sides of the other end of the cooling shaft. The spiral channel is connected to the cooling water inlet channel and cooling water outlet channel respectively. It also includes a low-pressure water cooling and energy recovery system, which comprises a low-pressure water channel, a standard pressure water channel, a thermal generator, a water tank, a differential pressure valve, a monitor, and a vacuum pump. The outlet of the low-pressure water channel is connected to the vacuum pump, and the inlet of the low-pressure water channel is connected to the differential pressure valve. The low-pressure water channel is interrupted in the middle and connected to both the cooling water inlet and outlet channels on the cooling shaft. The pressure inside the low-pressure water channel is lower than the standard pressure. The inlet of the standard pressure water channel is connected to the vacuum pump, and the outlet of the standard pressure water channel is connected to the differential pressure valve. The pressure inside the standard pressure water channel is standard atmospheric pressure. The thermal generator is located at the inlet of the standard pressure water channel and is also threadedly connected to the vacuum pump. The water tank is located in the middle of the standard pressure water channel. The pressure water channel is disconnected in the middle and threadedly connected to the water tank; the water tank contains cooling water; the differential pressure valve has a rated pressure difference. When the pressure difference between the standard pressure water channel and the low-pressure water channel reaches the rated pressure difference, the differential pressure valve is opened; when the pressure difference between the standard pressure water channel and the low-pressure water channel is lower than the rated pressure difference, the differential pressure valve is closed; the monitor has temperature sensors installed at various points on the hub motor. The monitor is connected to the vacuum pump via wires. The monitor transmits commands to the vacuum pump based on the temperature signals transmitted by the temperature sensors; the vacuum pump adjusts the pressure in the low-pressure water channel according to the commands from the monitor; the vacuum pump has three speed settings. In the first speed setting, the differential pressure valve is closed; in the second and third speed settings, the differential pressure valve is open; in the third speed setting, the vacuum pump suction is increased.

2. The low-pressure water-cooled energy recovery system for a hub motor according to claim 1, characterized in that: In the first gear, the vacuum pump operates, resulting in low pressure in the low-pressure water channel, but the pressure difference between the low-pressure water channel and the standard pressure water channel is lower than the rated pressure difference of the differential pressure valve. In the second gear, the vacuum pump continues to operate, causing the pressure in the low-pressure water channel to continue to decrease. The pressure difference between the low-pressure water channel and the standard pressure water channel equals the rated pressure difference of the differential pressure valve, and the differential pressure valve opens. In the third gear, the vacuum pump continues to operate, increasing the suction force of the vacuum pump and increasing the flow rate and velocity of the cooling water.

3. The low-pressure water-cooled energy recovery system for a hub motor according to claim 1, characterized in that: The protective cover is placed between the motor stator and the brake caliper.

4. The low-pressure water-cooled energy recovery system for a hub motor according to claim 1, characterized in that: The protective cover is placed between the motor stator and the brake caliper.

5. The low-pressure water-cooled energy recovery system for a hub motor according to claim 1, characterized in that: The cooling water inlet and outlet channels on the cooling shaft are connected to the low-pressure water channel by screws.

6. The low-pressure water-cooled energy recovery system for a hub motor according to claim 1, characterized in that: The low-pressure water channel is connected to the vacuum pump and differential pressure valve by welding.

7. The low-pressure water-cooled energy recovery system for a hub motor according to claim 1, characterized in that: The vacuum pump, the thermal generator, the thermal generator, the standard pressure water channel, the water tank, and the differential pressure valve are all connected by threaded connections.

8. The low-pressure water-cooled energy recovery system for a hub motor according to claim 1, characterized in that: The rated differential pressure of the differential pressure valve is 0.097 MPa.

9. A method for recovering low-pressure water-cooled energy using the low-pressure water-cooled energy recovery system for hub motors according to any one of claims 1 to 8, characterized in that: Includes the following parts: ① The vacuum pump and differential pressure valve divide the water channel into a low-pressure water channel and a standard pressure water channel. The standard pressure water channel is at room temperature and the boiling point of the cooling water is normal. ② The monitor monitors the temperature of the hub motor in real time and sends a signal to the vacuum pump based on the maximum temperature value. The vacuum pump adjusts the pressure in the low-pressure water channel according to the signal, and then controls the opening and closing of the differential pressure valve. ③ The pressure inside the low-pressure water channel is low, the boiling point of water is low, and when the differential pressure valve is opened, the cooling water spirals into the interior of the cooling shaft, covering the cooling shaft to the maximum extent, and the cooling water vaporizes and absorbs heat. ④ When the cooling water enters the standard pressure water channel, the boiling point returns to normal, the cooling water liquefies and releases heat, and the heat is converted into electrical energy by the heat generator to supply the car battery pack.

10. The low-pressure water-cooled energy recovery method according to claim 9, characterized in that: The monitor tracks the maximum temperature of the wheel hub motor using various temperature sensors. When the maximum temperature is below 45°C, the monitor controls the vacuum pump to operate at the first speed setting. When the maximum temperature reaches 45°C, the monitor controls the vacuum pump to operate at the second speed setting. When the maximum temperature drops to 35°C, the monitor controls the vacuum pump to return to the first speed setting. When the maximum temperature reaches 45°C and continues to rise to 50°C, the monitor controls the vacuum pump to operate at the third speed setting, thereby controlling the overall temperature of the wheel hub motor below 35°C.

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