High-reliability high-speed high-power permanent magnet driving motor capable of preventing electrocorrosion

Abstract

The invention discloses a high-reliability, high-speed and high-power permanent magnet driving motor capable of preventing electrocorrosion, and relates to the technical field of motors. An injection molding insulation shaft in a permanent magnet motor body and a shaftless rotor are connected and assembled to form a rotor assembly, a stator assembly is connected with the rotor assembly through a front end cover and a rear end cover, the front end of the injection molding insulation shaft is connected with a coupler, the front end cover is provided with an oil seal and forms dynamic sealing with the injection molding insulation shaft, and a labyrinth type dustproof ring is assembled on the coupler. The front end and the rear end of the injection molding insulation shaft are connected with a front bearing and a rear bearing respectively, a front bearing injection molding insulation ring and a rear bearing injection molding insulation ring are arranged between an inner ring of the front bearing and the injection molding insulation shaft and between an inner ring of the rear bearing and the injection molding insulation shaft respectively, and the outer side of the front bearing is provided with a bearing clamping ring on the insulation shaft. And a bearing inner small cover for fixing a bearing outer ring is mounted on the inner side of the front bearing. Electrocorrosion of the bearing can be effectively prevented, the performance of the motor is improved, the service life of the bearing is prolonged, and the operation reliability of the high-speed high-power permanent magnet motor is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and in particular to a high-reliability, high-speed, high-power permanent magnet drive motor that is resistant to electrical corrosion. Background Art

[0002] With the development of high frequency, high voltage, high speed and high power in automobile motors, the problem of electrical corrosion of drive system bearings is becoming more and more common.

[0003] Bearing electrical corrosion is primarily caused by shaft voltage and current generated during motor operation. These voltages and currents degrade the insulation properties of the bearing lubricant, creating a potential difference between the inner and outer races, leading to electrical corrosion. Specific causes include: ① Shaft voltage: Voltage induced on the shaft during motor operation due to an unbalanced stator magnetic field or the inherent magnetization of the shaft. ② Shaft current: Current is generated within the circuit formed by the shaft, bearing inner race, oil film, bearing outer race, and housing when the oil film insulation is broken. Electrical corrosion can cause corrosion at both ends of the bearing balls, damaging the balls and raceways, generating operating noise. In severe cases, it can burn out the bearing, cause bearing seizure, and force downtime, resulting in accidents and impacting motor operation and driver safety. Furthermore, electrical corrosion can cause tiny pits on the bearing surface. These pits gradually aggregate to form evenly spaced pit grooves, known as "washboard" patterns, which impact bearing performance and service life. Electrical corrosion has become a common problem for all automotive OEMs.

[0004] In order to prevent and reduce bearing electrical corrosion, the current improvement measures can generally take the following methods:

[0005] (1) Insulated bearings: Coating a layer of insulating material on the bearing is equivalent to adding a larger capacitor, which requires a higher breakdown voltage to protect the bearing.

[0006] (2) Ceramic ball bearings: Ceramics have good insulation properties and can be used in bearings to reduce the occurrence of electrical corrosion.

[0007] (3) Ensure neutral point balance in motor design: By adjusting the motor design, ensure neutral point balance and reduce the generation of shaft voltage.

[0008] (4) Conductive ring, additional brush short circuit: add brushes between the bearing chamber and the shaft to allow the current to pass through the brushes instead of through the bearings to avoid electrical corrosion.

[0009] (5) Conductive grease oil bearings, use grease with insulating properties: Use grease with insulating properties in bearings to reduce the occurrence of electrical corrosion.

[0010] The above measures can effectively prevent and mitigate bearing electrical corrosion to a certain extent, improving the service life and performance of motors and bearings. However, the following disadvantages still exist: insulated bearings are expensive, and the insulation layer is easily worn and detached; ceramic ball bearings are expensive, and the ceramic layer is easily broken by impact; conductive rings can only partially shunt the differential mode voltage and cannot completely eliminate the shaft current; conductive grease-oiled bearings can also only partially shunt the differential mode voltage and cannot completely eliminate the shaft current, thus reducing the occurrence of electrical corrosion. The life of the conductive grease affects the life of the bearing, reducing the reliability of the bearing operation, and thus the reliability of the motor operation.

[0011] In summary, the above measures all have limitations, high costs, and low reliability, and cannot completely and thoroughly solve the problem of bearing electrical corrosion. In recent years, the problem of bearing electrical corrosion has been widespread in the new energy vehicle industry (including new energy passenger cars, buses, light trucks, heavy trucks, etc.). The reason is that with the superposition of technical factors such as high voltage, high speed, high frequency, and high power of electric drive systems, the probability of shaft voltage breaking through the bearing oil film has been greatly increased. Therefore, the cause of bearing electrical corrosion is the electric drive system itself. There is a general consensus in the industry and academia on this issue, so a solution must be found from the motor and electronic control. Based on this, it is particularly necessary to design a high-reliability, high-speed, and high-power permanent magnet drive motor that can resist electrical corrosion. Summary of the Invention

[0012] In view of the deficiencies in the prior art, the present invention aims to provide a highly reliable, high-speed, high-power permanent magnet drive motor that is resistant to electrical corrosion. The motor has a reasonable structural design, prevents electrical corrosion of the bearings, improves the operating reliability of the high-speed, high-power permanent magnet motor, improves the performance of the motor and the service life of the bearings, and is easy to promote and use.

[0013] In order to achieve the above-mentioned purpose, the present invention is realized through the following technical scheme: a high-reliability, high-speed, high-power permanent magnet drive motor that is resistant to electrical corrosion, including a coupling, a stator assembly, a rotor assembly, a front cover, a rear cover, a housing, an injection-molded insulating shaft, an oil seal, a labyrinth dust ring, a front bearing, a rear bearing, a front bearing injection-molded insulating ring, a rear bearing injection-molded insulating ring, a bearing clamp and a small inner cover of the bearing, the front cover, the rear cover and the housing are assembled to form the body of the permanent magnet motor, the injection-molded insulating shaft inside the body is connected to the shaftless rotor to form a rotor assembly, a stator assembly is arranged on the periphery of the rotor assembly, and the stator assembly is connected to the rotor assembly through the front cover and the rear cover. The front end of the injection-molded insulating shaft is connected to the coupling, and the front end cover is equipped with an oil seal to form a dynamic seal with the injection-molded insulating shaft. The coupling is also equipped with a labyrinth dust ring to prevent mud and sand from entering the oil seal, which forms a dust-proof and waterproof effect with the front end cover. The front and rear ends of the injection-molded insulating shaft are respectively connected to the front bearing and the rear bearing for fixing and supporting the stable rotation of the shaft. The front bearing injection-molded insulating ring and the rear bearing injection-molded insulating ring are respectively arranged between the inner rings of the front bearing and the rear bearing and the injection-molded insulating shaft to completely insulate the bearing from the rotating shaft. A bearing retaining ring is installed on the insulating shaft on the outside of the front bearing, and a small bearing inner cover for fixing the outer ring of the bearing is installed on the inside of the front bearing.

[0014] Preferably, the internal splines of the coupling and the external splines of the injection-molded insulating shaft are interference-fitted and assembled by a shrink-fit process to prevent the coupling from loosening or tooth breakage.

[0015] Preferably, the oil seal is reversely assembled at the inner hole of the front end cover to form a dynamic seal with the injection-molded insulating shaft, thereby playing a sealing role. The oil seal opening of the oil seal is set inward, and the anti-loosening spring is on the inside, which can protect the spring from contact with water and prevent rust, thereby eliminating the problem of rust.

[0016] Preferably, the front bearing injection-molded insulating ring and the rear bearing injection-molded insulating ring are both made of PPS reinforced composite insulating material, which can completely insulate the bearing from the rotating shaft and prevent electrical corrosion of the bearing.

[0017] Preferably, the surface of the injection-molded insulating shaft is carburized and quenched to a hardness of HRC52-60 and a carburized layer thickness of 0.8-1 mm; the oil seal of the injection-molded insulating shaft is provided with a wear allowance, and the injection surface of the injection-molded insulating shaft is provided with vertical and horizontal straight lines to enhance the adhesion of the injection-molded body while preventing the injection-molded body from peeling off and slipping.

[0018] The beneficial effects of the present invention are as follows: the device can effectively prevent electrical corrosion of bearings, improve the performance of the motor and the service life of the bearings, and improve the operating reliability of high-speed, high-power permanent magnet motors, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments;

[0020] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention;

[0021] Figure 2 It is a planar half-section view of the present invention;

[0022] Figure 3 for Figure 2 A magnified schematic diagram of part D in FIG.

[0023] Figure 4 This is a schematic structural diagram of the injection-molded insulating shaft of the present invention;

[0024] Figure 5 This is a structural diagram of the injection-molded insulating shaft oil seal and injection-molded surface of the present invention;

[0025] Figure 6 for Figure 5 An enlarged schematic diagram of part E;

[0026] Figure 7 for Figure 5 Enlarged schematic diagram of part F. DETAILED DESCRIPTION

[0027] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below in conjunction with specific implementation methods.

[0028] Reference Figure 1-7, this specific embodiment adopts the following technical solutions: a high-reliability, high-speed, high-power permanent magnet drive motor that can prevent electrical corrosion, including a coupling 1, a stator assembly 2, a rotor assembly 3, a front cover 4, a rear cover 5, a housing 6, an injection-molded insulating shaft 7, an oil seal 8, a labyrinth dust ring 9, a front bearing 10, a rear bearing 11, a front bearing injection-molded insulating ring 12, a rear bearing injection-molded insulating ring 13, a bearing clamp 14 and a small bearing inner cover 15, the front cover 4, the rear cover 5 and the housing 6 are assembled to form the body of the permanent magnet motor, the injection-molded insulating shaft 7 inside the body is connected to the shaftless rotor to form a rotor assembly 3, the periphery of the rotor assembly 3 is provided with a stator assembly 2, the stator assembly 2 is connected to the rotor assembly 3 through the front cover 4 and the rear cover 5, the injection-molded insulating The front end of the flange shaft 7 is connected to the coupling 1, and the front end cover 4 is equipped with an oil seal 8, which forms a dynamic seal with the injection-molded insulating shaft 7. The coupling 1 is also equipped with a labyrinth dust ring 9, which forms a dust-proof and waterproof effect with the front end cover 4, and can prevent mud and sand from effectively entering the oil seal 8 and damaging the oil seal. The front and rear ends of the injection-molded insulating shaft 7 are respectively connected to the front bearing 10 and the rear bearing 11 for fixing and supporting the stable rotation of the shaft. The front bearing 10 and the rear bearing 11 are respectively provided with a front bearing injection-molded insulating ring 12 and a rear bearing injection-molded insulating ring 13 between the inner rings of the front bearing 10 and the injection-molded insulating shaft 7 to completely insulate the bearing from the rotating shaft. A bearing retaining ring 14 is installed on the outer side of the front bearing 10 on the insulating shaft, and a bearing inner small cover 15 for fixing the outer ring of the bearing is installed on the inner side of the front bearing 10.

[0029] It is worth noting that the internal splines of the coupling 1 and the external splines of the injection-molded insulating shaft 7 are interference fit and assembled through a shrink fit process to prevent hidden dangers such as coupling loosening, tooth breaking, and fastening bolt breakage, thereby improving the reliability of motor operation.

[0030] In addition, the oil seal 8 adopts a reverse-mounted structure and is assembled at the inner hole of the front end cover 4 to form a dynamic seal with the injection-molded insulating shaft 7, which plays a sealing role. The oil seal opening of the oil seal 8 is set inward, and the anti-loosening spring is on the inside, which can protect the spring from contact with water and prevent rust, thereby eliminating the problem of rust, thereby extending the service life of the oil seal and improving the reliability of motor operation.

[0031] In this embodiment, the surface of the injection molded insulating shaft 7 is subjected to carburizing and quenching treatment, and the hardness reaches HRC52-60, and the thickness of the carburized layer is 0.8-1mm. The shaft is subjected to low temperature tempering to eliminate stress. Figure 5 ) is the oil seal position, and 0.05 grinding allowance is reserved for the oil seal position. After the bearing position and the bearing position step are injection molded, they are clamped and ground together to the required matching tolerance size of the bearing and the oil seal, thereby ensuring the concentricity of the bearing and the oil seal to the central axis and improving the reliability of the motor operation; the B side and C side of the injection molded insulating shaft 7 ( Figure 5 ) is the injection molding surface, and the injection molding surface is treated with vertical and horizontal straight lines to enhance the adhesion of the injection molding body and prevent the injection molding body from peeling off and slipping.

[0032] In this embodiment, both the front bearing injection-molded insulating ring 12 and the rear bearing injection-molded insulating ring 13 are made of PPS-reinforced composite insulation material. The bearing seat on the rotating shaft and the injection-molded insulating layer between the shafts completely insulate the bearings from the rotating shaft, thereby completely blocking the shaft current generated by the shaft voltage, completely preventing electrical corrosion of the bearings, and improving the operational reliability of high-speed, high-power permanent magnet motors. This permanent magnet drive motor structure can replace traditional general new energy drive motors and be used as a drive motor in new energy commercial vehicles, effectively preventing and mitigating the problem of bearing electrical corrosion, and has broad market application prospects.

[0033] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A high-reliability, high-speed, high-power permanent magnet drive motor that is resistant to electrical corrosion, characterized in that: The invention comprises a coupling (1), a stator assembly (2), a rotor assembly (3), a front end cover (4), a rear end cover (5), a housing (6), an injection-molded insulating shaft (7), an oil seal (8), a labyrinth dust ring (9), a front bearing (10), a rear bearing (11), a front bearing injection-molded insulating ring (12), a rear bearing injection-molded insulating ring (13), a bearing clamp (14) and a bearing inner small cover (15); the front end cover (4), the rear end cover (5) and the housing (6) are assembled to form a permanent magnet motor body; the injection-molded insulating shaft (7) inside the body is connected to the shaftless rotor to form a rotor assembly (3); the stator assembly (2) is arranged on the periphery of the rotor assembly (3); the stator assembly (2) is connected to the rotor assembly (3) through the front end cover (4) and the rear end cover (5); the front end of the injection-molded insulating shaft (7) is connected to the coupling The coupling (1) is connected to the shaft, the front end cover (4) is equipped with an oil seal (8) to form a dynamic seal with the injection-molded insulating shaft (7), the coupling (1) is also equipped with a labyrinth dustproof ring (9) to prevent mud and sand from entering the oil seal, and the front end cover (4) forms a dustproof and waterproof structure, the front and rear ends of the injection-molded insulating shaft (7) are respectively connected with a front bearing (10) and a rear bearing (11) for fixing and supporting the stable rotation of the shaft, and a front bearing injection-molded insulating ring (12) and a rear bearing injection-molded insulating ring (13) are respectively arranged between the inner rings of the front bearing (10) and the rear bearing (11) and the injection-molded insulating shaft (7) to completely insulate the bearing from the rotating shaft, a bearing retaining ring (14) is installed on the outer side of the front bearing (10) on the insulating shaft, and a bearing inner small cover (15) for fixing the outer ring of the bearing is installed on the inner side of the front bearing (10) 2. The high-reliability, high-speed, high-power permanent magnet drive motor that is resistant to electrical corrosion according to claim 1, characterized in that: The inner spline of the coupling (1) and the outer spline of the injection-molded insulating shaft (7) are interference-fitted and assembled through a shrink-fit process to prevent the coupling from loosening or tooth breakage.

3. The high-reliability, high-speed, high-power permanent magnet drive motor that is resistant to electrical corrosion according to claim 1, characterized in that: The oil seal (8) is reversely mounted on the inner hole of the front end cover (4) to form a dynamic seal with the injection-molded insulating shaft (7), thereby playing a sealing role. The oil seal opening of the oil seal (8) is arranged inwardly, and the anti-loosening spring is on the inner side to protect the spring from contact with water and prevent rust.

4. The high-reliability, high-speed, high-power permanent magnet drive motor that is resistant to electrical corrosion according to claim 1, characterized in that: The front bearing injection-molded insulating ring (12) and the rear bearing injection-molded insulating ring (13) are both made of PPS reinforced composite insulating material, which can insulate the bearing from the rotating shaft and block the shaft current generated by the shaft voltage.

5. The high-reliability, high-speed, high-power permanent magnet drive motor that is resistant to electrical corrosion according to claim 1, characterized in that: The surface of the injection-molded insulating shaft (7) is carburized and quenched, and the thickness of the carburized layer is 0.8-1 mm.

6. The high-reliability, high-speed, high-power permanent magnet drive motor capable of resisting electrical corrosion according to claim 1, characterized in that: The oil seal of the injection-molded insulating shaft (7) is provided with a wear allowance, and the injection-molded surface of the injection-molded insulating shaft (7) is provided with vertical and horizontal straight lines, which enhance the bonding force of the injection-molded body and prevent the injection-molded body from peeling off and slipping off.

Images