A bearing-insulated electric drive system structure

Abstract

The application discloses a bearing-insulated electric drive system structure and belongs to the electric drive structure in an electric vehicle. The electric drive system structure comprises a motor front shell, a motor rear shell, a motor rear end cover, a motor shaft and a motor bearing. The motor shaft is internally provided with a de-electrization and impurity removal structure. The de-electrization and impurity removal structure comprises a first current collecting end, a second current collecting end, a coil and an impurity removal rod. When the structure is in a working state, the first current collecting end and the second current collecting end form an electric circuit between the two ends of the motor shaft, thereby reducing the electric charge on the surface of the motor shaft. The current passing through the coil makes the coil and the impurity removal rod combined into an electromagnet, which adsorbs the impurity particles in the lubricating oil. The application solves the problem in the prior art that when the lubricating oil is introduced into the motor, a large amount of electric charge is attached to the lubricating oil due to the friction between the lubricating oil and the motor shaft and the motor bearing, which increases the viscosity of the lubricating oil and reduces the lubricating effect.

Description

Technical Field

[0001] This invention relates to an electric drive structure in an electric vehicle, and more particularly to a bearing-insulated electric drive system structure. Background Technology

[0002] As a core technology of new energy vehicles, the motor assembly is increasingly developing towards integration, lightweighting, and low cost. As a rotating part, the motor relies heavily on bearings. However, high-speed rotating motors on the market often suffer from uneven magnetic reluctance. During high-speed rotation, a potential difference is generated at both ends of the motor shaft, causing shaft current to flow through the bearings and leading to electro-corrosion. This affects the motor's lifespan and reliability. Therefore, preventing shaft current from causing electro-corrosion in the bearings is of paramount importance.

[0003] For example, the Chinese patent document "Bearing Insulation Device, Manufacturing Method of Bearing Insulation Device, and Variable Frequency Motor" (publication number CN103607065B) discloses a bearing insulation device for a variable frequency motor. This device includes an inner steel sleeve and an outer steel sleeve. The inner steel sleeve is used to wrap around and fix the outer ring of the bearing in the variable frequency motor, and its end face cannot be electrically connected to the end cover of the motor. The outer steel sleeve is outside the inner steel sleeve, and an insulating layer is provided between the outer and inner steel sleeves. This bearing insulation device can prevent the outer circumference of the bearing outer ring from directly contacting the end cover, preventing the bearing from forming a series circuit through direct contact between its outer circumferential surface and the end cover, eliminating the electro-corrosion effect of high-frequency shaft current on the bearing, and improving the bearing's service life.

[0004] For example, the "Insulated and Corrosion-Resistant Brushless DC Motor" disclosed in Chinese patent literature, with publication number CN211981650U, includes a rotating shaft, a first end shell, and a second end shell. The first and second end shells are fastened together. The first end shell has a first bearing, and the second end shell has a second bearing. The rotating shaft is rotatably mounted between the first and second bearings. The connection points between the rotating shaft and the first and second bearings are coated with insulating material layers. This utility model, by setting an insulating material layer between the rotating shaft, bearings, and rotor core, shares the induced voltage difference between the inner and outer sides of the bearings, reducing the risk of the induced voltage difference breaking down the lubricating oil and damaging the bearings, thereby improving the service life of the motor.

[0005] However, the above technologies have shortcomings. They all use an insulating layer to isolate the motor bearing from the motor housing, thereby avoiding electro-corrosion of the motor bearing. However, since an electrical circuit cannot be formed, the potential difference on the motor shaft will cause positive and negative charges to accumulate on the surfaces of both ends of the motor shaft. When lubricating oil is introduced, due to the friction between the lubricating oil and the motor shaft and motor bearing, a large amount of charge will adhere to the lubricating oil, which will increase the viscosity of the lubricating oil and reduce the lubrication effect. Furthermore, the mixing of lubricating oils with positive and negative charges can easily create safety hazards.

[0006] For example, the patent document "Lubricating Oil or Fuel Supply Device for Vehicles" (publication number CN105799623B) discloses an improvement in the operational responsiveness of an internal combustion engine by destatically removing static electricity from the lubricating oil or fuel. A coarse filter for the lubricating oil or fuel is disposed at the bottom of a container storing the lubricating oil or fuel, and the container and the lubricating oil or fuel stored within it carry a positive charge. A self-discharge static eliminator is installed on the outer side of the bottom wall of the container, corresponding to the back side of the portion facing the coarse filter, and is used to destatically remove static electricity from the lubricating oil or fuel flowing into the coarse filter.

[0007] The shortcoming of the above patent is that it can only be applied to the elimination of static electricity in the lubricating oil container, but cannot reduce the charge adhering to the lubricating oil during the contact between the motor shaft and the lubricating oil.

[0008] Therefore, there is a need for an electric drive system structure that can insulate bearings and reduce the charge carried in the lubricating oil. Summary of the Invention

[0009] This invention aims to overcome the problems in existing electric drive systems with insulated bearings, where, when lubricating oil is introduced into the motor, a large amount of charge adheres to the lubricating oil due to friction between the lubricating oil and the motor shaft and bearings. This increases the viscosity of the lubricating oil, reduces its lubrication effect, and the mixing of lubricating oils with positive and negative charges can easily create safety hazards. The invention provides a bearing-insulated electric drive system structure that reduces the charge attached to the lubricating oil and removes impurities from the lubricating oil, preventing these impurities from entering the bearing and causing damage.

[0010] To achieve the above objectives, the present invention adopts the following technical solution: This invention discloses a bearing-insulated electric drive system structure, comprising a front motor housing, a rear motor housing, a rear motor end cover, a motor shaft, and motor bearings. The motor bearings include a front motor bearing and a rear motor bearing. The front end of the motor shaft is mounted on the front motor housing via the front motor bearing, and the rear end of the motor shaft is mounted on the rear motor housing via the rear motor bearing. An insulating steel sleeve is installed on the outer surface of the motor bearings. A lubricating oil cavity is provided inside the motor shaft, and the lubricating oil cavity is connected to the outside of the motor shaft through a lubricating oil channel. A de-energizing and impurity removal structure is also provided inside the motor shaft. The de-energizing and impurity removal structure includes a first collector terminal, a second collector terminal, a coil, and a de-energizing rod. The two ends of the coil are respectively connected to the first collector terminal and the second collector terminal. The de-energizing rod is a metal rod and is detachably installed inside the lubricating oil cavity, located on the axis of the coil. When the structure is in operation, the first collector terminal and the second collector terminal form an electrical circuit between the two ends of the motor shaft, thereby reducing the charge on the surface of the motor shaft. The current passing through the coil causes the coil and the de-energizing rod to combine into an electromagnet, adsorbing impurity particles in the lubricating oil.

[0011] When the electric drive system is in operation, the motor shaft rotates while throwing the lubricating oil in the lubrication chamber outward through the lubrication oil channel, allowing the lubricating oil to enter the motor bearing. The motor shaft, the first collector terminal, the coil, and the second collector terminal are sequentially connected to form a circuit, thereby preventing the accumulation of charge at both ends of the motor shaft, reducing the amount of charge in the lubricating oil, and thus reducing the viscosity of the lubricating oil and improving the lubrication effect. At the same time, since current flows through the coil, the coil and the impurity removal rod form an electromagnet, which can adsorb impurity particles in the lubricating oil as it passes through, preventing impurity particles from entering the motor bearing and causing wear.

[0012] Preferably, the lower part of the rear housing of the motor is provided with an oil collection groove, and the rear end cover of the motor is provided with a mechanical pump for drawing the lubricating oil in the oil collection groove into the lubricating oil chamber. The lubricating oil in the motor can be circulated through the oil collection groove and the mechanical pump. Since the lubricating oil needs to circulate through multiple structures inside the motor, it is easier for impurity particles to mix into the lubricating oil. The function of the impurity removal rod in this solution to adsorb impurity particles provides the conditions for the circulation of lubricating oil.

[0013] Preferably, the rear end cover of the motor is provided with an oil passage connecting the oil collection tank and the mechanical pump. The oil passage includes a heat dissipation section for heat exchange with the outside air. Since the temperature of the lubricating oil gradually increases during the friction between the lubricating oil and the motor shaft and bearings, the heat dissipation section in the oil passage can ensure that the lubricating oil is cooled by the heat dissipation section during each cycle, thereby avoiding the lubricating oil temperature from becoming too high.

[0014] Preferably, the mechanical pump includes a drive shaft, and the motor shaft and the drive shaft are connected by a coupling structure, which enables the motor shaft and the drive shaft to rotate synchronously. The coupling structure enables the motor shaft to drive the drive shaft to rotate, thereby eliminating the need for an additional power source to drive the mechanical pump and ensuring the synchronization of the motor start-up and the oil extraction process.

[0015] Preferably, the coupling structure includes a sealing sleeve, one end of which is fitted onto the outside of the motor shaft, and the other end has an opening. The drive shaft is installed in the opening and fixedly connected to the opening. The drive shaft has a drive shaft oil passage, one end of which is connected to an oil circuit, and the other end is connected to the lubricating oil cavity. The above structure ensures better sealing during the process of lubricating oil passing through the coupling structure into the lubricating oil cavity.

[0016] Preferably, the surface of the impurity removal rod is provided with a plurality of impurity grooves for retaining impurity particles in the lubricating oil; the impurity grooves can retain impurities attached to the lubricating oil, and even if the motor stops running and the magnetism of the impurity removal rod weakens, the impurities will not easily fall off the surface of the impurity removal rod.

[0017] Preferably, the lubricating oil channel includes a front channel for introducing lubricating oil into the front motor bearing and a rear channel for introducing lubricating oil into the rear motor bearing. The first collector is a metal sleeve installed in the front channel, and the second collector is a metal sleeve installed in the rear channel. Since the lubricating oil must pass through the lubricating oil channel when entering the motor bearing, placing the collector in the lubricating oil channel can better reduce the charge carried in the lubricating oil.

[0018] Preferably, the insulating steel sleeve includes a connecting part and an insulating part. The connecting part is a steel sleeve, and the insulating part is a plastic sleeve integrated onto the connecting part by injection molding. The insulating part is limited by the rear housing of the motor. The steel sleeve is used to improve the reliability of the installation of the insulating steel sleeve. The plastic sleeve can not only play the role of insulation to prevent shaft voltage from breaking down the bearing, but also play the role of buffering and vibration reduction, and reduce the noise generated.

[0019] Therefore, the present invention has the following beneficial effects: (1) it reduces the charge attached to the lubricating oil, thereby reducing the viscosity of the lubricating oil and improving the lubricating effect; (2) the lubricating oil forms a circulation in the motor, reducing losses; (3) it can remove impurities in the lubricating oil during the lubricating oil circulation process, preventing impurities from entering the bearing and causing damage to the bearing; (4) it can dissipate heat from the lubricating oil during the lubricating oil circulation process, preventing its temperature from being too high; (5) it can buffer and dampen the bearing, and reduce the noise generated; (6) the insulating steel sleeve can prevent the shaft voltage from breaking down the bearing and causing electro-corrosion of the bearing. Attached Figure Description

[0020] Figure 1 This is a cross-sectional schematic diagram of the present invention.

[0021] Figure 2 This invention is in Figure 1 A magnified view of a portion of the image.

[0022] Figure 3 This is a cross-sectional structural schematic diagram of the insulating steel sleeve of the present invention.

[0023] Figure 4 This is a schematic diagram of one structure of the present invention.

[0024] In the diagram: 1. Front housing of motor; 2. Rear housing of motor; 3. Rear end cover of motor; 4. Motor shaft; 5. Motor bearing; 6. Front insulating steel sleeve; 7. Rear insulating steel sleeve; 8. Radial limiting part; 9. Axial limiting part; 10. Connecting part; 11. Insulating part; 12. Oil collection groove; 13. Heat dissipation section; 14. Lubricating oil cavity; 15. Drive shaft; 16. Drive shaft oil passage; 17. Sealing sleeve; 18. First collector end; 19. Second collector end; 20. Coil; 21. Impurity removal rod; 22. Limiting support foot; 23. Disassembly groove; 24. Impurity groove; 25. Lubricating oil channel. Detailed Implementation

[0025] The present invention will now be further described with reference to the accompanying drawings and specific embodiments.

[0026] like Figure 1-4In the illustrated embodiment, a bearing-insulated electric drive system structure includes a front motor housing 1, a rear motor housing 2, a rear motor end cover 3, a motor shaft 4, and a motor bearing 5. The motor bearing includes a front motor bearing and a rear motor bearing. The front end of the motor shaft is mounted on the front motor housing via the front motor bearing, and the rear end of the motor shaft is mounted on the rear motor housing via the rear motor bearing. An insulating steel sleeve is installed on the outer surface of the motor bearing. A front insulating steel sleeve 6 is installed between the front motor housing and the front motor bearing, and a rear insulating steel sleeve 7 is installed between the rear motor housing and the rear motor bearing. The insulating steel sleeve includes a radial limiting part 8 that fits around the outside of the motor bearing, and a radial limiting part... The axial limiting part 9 is vertical. The axial limiting part of the front insulating steel sleeve fits against the outer ring of the front motor bearing, while there is a gap between the axial limiting part of the rear insulating steel sleeve and the outer ring of the rear motor bearing. A wave spring is installed between the two for pressing the bearing. The insulating steel sleeve includes a connecting part 10 and an insulating part 11. The connecting part is a steel sleeve, and the insulating part is a plastic sleeve integrated into the connecting part by injection molding. The steel sleeve is made of 45 steel, and the plastic sleeve is preferably made of PEEK material, but is not limited to glass fiber or other high-strength insulating materials. This arrangement can effectively reduce the vibration transmitted from the motor to the motor housing, rear motor housing, etc. through the bearing, and reduce the noise of the electric drive system.

[0027] The lower part of the motor rear housing is provided with an oil collection groove 12, where the lubricating oil inside the motor collects after falling. A mechanical pump is installed in the motor rear end cover, and an oil passage is provided between the mechanical pump and the oil collection groove. The oil passage includes a heat dissipation section 13 that allows the lubricating oil to exchange heat with the outside air. The heat dissipation section has a flat cross-sectional shape, and the thickness of the motor rear end cover portion between the heat dissipation section and the outside air does not exceed 3mm. A lubricating oil chamber 14 is provided inside the motor shaft. The mechanical pump includes a drive shaft 15, and a drive shaft oil passage 16 is provided inside the drive shaft. One end of the drive shaft oil passage is connected to the oil passage, and the other end is connected to the lubricating oil chamber. The motor shaft and the drive shaft are connected by a coupling structure, which allows the motor shaft and the drive shaft to rotate synchronously. The coupling structure includes a sealing sleeve 17, one end of which is fitted onto the outside of the motor shaft, and the other end has an opening. The drive shaft is installed in the opening and is fixedly connected to the opening.

[0028] The motor shaft is also equipped with a current removal and impurity removal structure, which includes a first current collector 18, a second current collector 19, a coil 20, and an impurity removal rod 21. The two ends of the coil are respectively connected to the first current collector and the second current collector. The impurity removal rod is a metal rod and is detachably installed in the lubrication oil cavity. The impurity removal rod, the coil, and the motor shaft are arranged coaxially. The lubrication oil cavity is provided with a limiting foot 22 for radially limiting the impurity removal rod. The side of the impurity removal rod facing the rear end cover of the motor is provided with a disassembly groove 23, which facilitates removal and cleaning using a T-head tool. The opening of the disassembly groove is rectangular, and the bottom of the disassembly groove... The part is a rectangular groove with a diameter larger than the long side of the opening. After the T-head tool is inserted into the opening, rotated 90° and then pulled out, the impurity removal rod can be removed from the lubricating oil cavity. The surface of the impurity removal rod is provided with several impurity grooves 24 for retaining impurity particles in the lubricating oil. The lubricating oil cavity is connected to the outside of the motor shaft through a lubricating oil channel 25. The lubricating oil channel includes a front channel for introducing lubricating oil into the front motor bearing and a rear channel for introducing lubricating oil into the rear motor bearing. The first collector is a copper sleeve installed in the front channel and the second collector is a copper sleeve installed in the rear channel.

[0029] When the electric drive system is running, the motor shaft rotates. Simultaneously, a potential difference is created between its two ends, forming a circuit between the motor shaft, the first collector terminal, the coil, and the second collector terminal. This generates current in the coil and magnetizes the impurity removal rod. At the same time, the motor shaft drives the drive shaft of the mechanical pump, drawing lubricating oil from the oil collection tank into the lubricating oil chamber. Due to the motor's rotation, the lubricating oil in the lubricating oil chamber enters the motor bearing through the lubricating oil channel. As the lubricating oil passes through the lubricating oil chamber, impurity particles attached to it are adsorbed into the impurity grooves on the impurity removal rod. Because a circuit is formed on the motor shaft, the lubricating oil is less likely to acquire an electrical charge during contact with the motor shaft, thus reducing the viscosity of the lubricating oil and improving the lubrication effect.

[0030] During the maintenance of the electric drive system, the impurity removal rod can be removed. Since the rod is no longer magnetic, it can easily remove impurities from the impurity tank.

Claims

1. A bearing-insulated electric drive system structure, comprising a front motor housing, a rear motor housing, a rear motor end cover, a motor shaft, and motor bearings, wherein the motor bearings include a front motor bearing and a rear motor bearing, the front end of the motor shaft is mounted on the front motor housing via the front motor bearing, and the rear end of the motor shaft is mounted on the rear motor housing via the rear motor bearing, characterized in that, An insulating steel sleeve is installed on the outer surface of the motor bearing. A lubricating oil cavity is provided inside the motor shaft, and the lubricating oil cavity is connected to the outer side of the motor shaft through a lubricating oil channel. A de-energizing and impurity removal structure is also provided inside the motor shaft. The de-energizing and impurity removal structure includes a first collector terminal, a second collector terminal, a coil, and an impurity removal rod. The two ends of the coil are respectively connected to the first collector terminal and the second collector terminal. The impurity removal rod is a metal rod and is detachably installed in the lubricating oil cavity. The impurity removal rod is located on the axis of the coil. When the structure is in working condition, the first collector terminal and the second collector terminal form an electrical circuit between the two ends of the motor shaft, thereby reducing the charge on the surface of the motor shaft. The current passing through the coil causes the coil and the impurity removal rod to combine into an electromagnet, which adsorbs impurity particles in the lubricating oil. The lubricating oil channel includes a front channel for introducing lubricating oil into the front motor bearing and a rear channel for introducing lubricating oil into the rear motor bearing. The first collector is a metal sleeve installed in the front channel, and the second collector is a metal sleeve installed in the rear channel.

2. The bearing-insulated electric drive system structure according to claim 1, characterized in that, The lower part of the rear housing of the motor is provided with an oil collection groove, and the rear end cover of the motor is provided with a mechanical pump for drawing the lubricating oil in the oil collection groove into the lubricating oil chamber.

3. The bearing-insulated electric drive system structure according to claim 2, characterized in that, The motor's rear end cover is equipped with an oil passage connecting the oil collection tank and the mechanical pump. The oil passage includes a heat dissipation section for heat exchange with the outside air.

4. The bearing-insulated electric drive system structure according to claim 3, characterized in that, The mechanical pump includes a drive shaft, and the motor shaft and the drive shaft are connected by a coupling structure, which enables the motor shaft and the drive shaft to rotate synchronously.

5. The bearing-insulated electric drive system structure according to claim 4, characterized in that, The coupling structure includes a sealing sleeve, one end of which is fitted onto the outside of the motor shaft, and the other end has an opening. The drive shaft is installed in the opening and fixedly connected to the opening. The drive shaft has a drive shaft oil passage, one end of which is connected to an oil circuit, and the other end is connected to the lubricating oil chamber.

6. The bearing-insulated electric drive system structure according to claim 1, characterized in that, The surface of the impurity removal rod is provided with several impurity grooves for retaining impurity particles in the lubricating oil.

7. A bearing-insulated electric drive system structure according to any one of claims 1-6, characterized in that, The insulating steel sleeve includes a connecting part and an insulating part. The connecting part is a steel sleeve, and the insulating part is a plastic sleeve integrated onto the connecting part by injection molding. The insulating part is limited by the rear housing of the motor.

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