Device for preventing electric corrosion of motor bearing and motor

Abstract

The utility model discloses a device for preventing electrocorrosion of a motor bearing and a motor, the device comprises a conductive mounting seat, the front end of the conductive mounting seat is fixedly provided with a conductive fiber bundle, the conductive fiber bundle is located on the central axis of the motor and is in extrusion fit with the axis of the end face of a rotating shaft of the motor, and the conductive fiber bundle is provided with a nickel-plated layer. And the rear end of the conductive mounting seat is in threaded connection with the motor rear end cover and is used for adjusting the extrusion amount of the conductive fiber bundle. According to the utility model, the conductive fiber is contacted with the axis, and the linear speed of the contact point is almost close to zero, thereby greatly reducing the drag loss and fiber wear of the motor, and ensuring the efficiency of the motor and the cleanliness of the cavity.

Description

Technical Field

[0001] The utility model relates to a device for preventing electric corrosion of motor bearings and a motor with the device. Background Art

[0002] Electrical corrosion is one of the factors that cause premature failure of motor bearings. Under the influence of the high switching frequency and high common-mode voltage of the inverter, a potential difference is formed between the motor shaft and the casing through the coupling of the internal capacitance of the motor. The potential difference forms a shaft current flowing through the inner and outer rings of the bearing.

[0003] Currently, with the significant increase in motor speed, the viscosity of the lubricant selected for motor bearings is becoming smaller and smaller, and the oil film thickness is also becoming lower and lower.

[0004] When the shaft voltage exceeds the critical withstand voltage of the bearing lubricant, the current breaks down the lubricant film, generating high temperatures and causing localized melting and uneven surface corrosion. Damage to the motor bearings can also reduce user comfort and even lead to motor failure and user safety.

[0005] Currently, there are three mainstream measures in the industry to solve this problem: 1. System optimization, 2. Insulation blocking, and 3. Shaft current diversion.

[0006] System optimization measures generally include optimizing the motor structure or process, reducing the low-frequency shaft voltage generated by the asymmetric internal magnetic field caused by motor structural asymmetry due to design, manufacturing, and assembly, and lowering the high-frequency common-mode voltage generated by the excitation source. However, with the application of SiC and the development of 800V high-voltage platforms, system optimization has limited effect on improving shaft voltage levels. Second, insulation blocking measures generally use ceramic ball bearings or bearings with insulated inner and outer rings, but these are generally expensive and difficult for users to accept.

[0007] Shaft current drainage usually uses conductive carbon rods or conductive fibers to drain the shaft current to the casing to eliminate the induced potential on the shaft and reduce or eliminate the potential difference between the inner and outer rings of the bearing.

[0008] Chinese patent document CN217036976U discloses a solution in which conductive fibers are evenly arranged around the circumference of a metal ring, thereby making radial contact with the outer diameter of the rotating shaft. However, at high motor speeds, the outer diameter contact line velocity is high, resulting in high fiber drag torque, frictional resistance, and wear. This wear powder affects the cleanliness of the motor's interior.

[0009] To this end, the utility model proposes a new shaft current diversion measure to overcome the problem of conductive fiber wear powder affecting the internal cleanliness of the motor while ensuring the unloading and diversion of the shaft current. Utility Model Content

[0010] The purpose of the utility model is to provide a device for preventing electric corrosion of motor bearings and a motor using the device, so as to effectively ensure the unloading and diversion of shaft current.

[0011] To this end, the utility model provides, on the one hand, a device for preventing electrical corrosion of motor bearings, including a conductive mounting seat, a conductive fiber bundle being fixed to the front end of the conductive mounting seat, the conductive fiber bundle being located on the central axis of the motor and being extruded and fitted with the axis of the end face of the motor shaft, the conductive fiber bundle having a nickel-plated layer, and the rear end of the conductive mounting seat being screwed to the rear end cover of the motor for adjusting the extrusion amount of the conductive fiber bundle.

[0012] Furthermore, the extrusion amount of the conductive fiber bundle is 1-3 mm.

[0013] Furthermore, the conductive fiber bundle is a single conductive fiber bundle and the single conductive fiber bundle has a surface nickel plating layer.

[0014] Furthermore, the conductive mounting seat has an external hexagonal mounting portion.

[0015] Furthermore, the conductive mounting seat has a central cavity, and the cavity wall of the central cavity has symmetrically arranged and extrudable thin-walled parts for riveting and fixing the conductive fiber bundle.

[0016] According to another aspect of the present invention, a motor for preventing electrical corrosion of bearings is provided, comprising a stator housing, a rotor, a front bearing, a rear bearing, a motor front cover and a motor rear cover, wherein the motor rear cover has a seat cavity for placing the above-mentioned device for preventing electrical corrosion of motor bearings.

[0017] Compared with the prior art, the present invention has the following technical effects:

[0018] 1. This conductive mount adopts the shaft end contact method; the conductive fiber contacts the shaft center, and the linear velocity of the contact point is almost close to zero, which greatly reduces the drag loss and fiber wear on the motor, ensuring the motor efficiency and cavity cleanliness;

[0019] 2. Single bundle of conductive fiber, riveted in place at one time, simple structure and low cost;

[0020] 3. The conductive mounting seat adopts an external hexagonal thread design, which is easy and quick to install.

[0021] In addition to the above-described purposes, features and advantages, the present invention has other purposes, features and advantages. The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings constituting part of this application are provided to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are provided to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0023] Figure 1 This is a schematic structural diagram of a motor for preventing internal corrosion of bearings according to the present invention;

[0024] Figure 2 yes Figure 1 An enlarged schematic diagram of the structure of the motor end cover;

[0025] Figure 3 It is a structural schematic diagram of a device for preventing electric corrosion of motor bearings according to the present invention. DETAILED DESCRIPTION

[0026] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0027] Combined with reference Figures 1 to 3 The motor for preventing electrical corrosion of bearings of the present invention includes a stator housing 1, a front bearing 2, a rotor 3, a motor front cover 4, a motor rear cover 5, a rear bearing 6, and a conductive mounting seat 7.

[0028] The motor rear cover 5 has a cavity seat 5 - 1 , which is used to arrange the conductive mounting seat 7 .

[0029] A conductive fiber bundle 7-1 is fixed to the front end of the conductive mounting seat 7. The conductive fiber bundle 7-1 is located on the central axis of the motor and is squeezed together with the axis of the rotor end face. The conductive fiber bundle 7-1 has a nickel-plated layer. The rear end of the conductive mounting seat is screwed to the motor rear cover 5 to adjust the extrusion amount of the conductive fiber bundle 7-1.

[0030] The conductive mounting seat 7 has a central cavity, and the cavity wall of the central cavity has a symmetrically arranged and extrudable thin-walled portion 7-2 for riveting and fixing the conductive fiber bundle.

[0031] The conductive fiber bundle 7-1 is inserted into the central cavity and fixed by rivet pressure by squeezing the thin wall portion 7-2. The built-in external hexagonal mounting portion 7-3 facilitates wrench installation and is connected to the cavity seat 5-1 of the motor back cover through thread 7-4.

[0032] The conductive fiber bundle 7-1 is extruded into the motor rotor 3 end face with a 1-3mm extrusion depth. The conductive fiber is nickel-plated to ensure a contact resistance of less than 1Ω, effectively conducting shaft current.

[0033] The shaft current in the motor is conducted to the housing through the conductive mounting base 7 and finally transmitted to the ground, so that there is no potential difference between the rotating shaft and the motor housing and between the inner and outer rings of the bearing, thereby preventing electrical corrosion of the motor bearings.

[0034] The above description is merely an embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, substitutions, or improvements made within the spirit and principles of the present invention shall be within the scope of protection of the present invention.

Claims

1. A device for preventing electrical corrosion of motor bearings, characterized in that: It includes a conductive mounting seat, the front end of which is fixed with a conductive fiber bundle. The conductive fiber bundle is located on the central axis of the motor and is extruded with the axis of the end face of the motor shaft. The conductive fiber bundle has a nickel-plated layer. The rear end of the conductive mounting seat is screwed to the rear end cover of the motor to adjust the extrusion amount of the conductive fiber bundle.

2. The device for preventing electric corrosion of motor bearings according to claim 1, characterized in that: The extrusion amount of the conductive fiber bundle is 1-3 mm.

3. The device for preventing electric corrosion of motor bearings according to claim 1, characterized in that: The conductive fiber bundle is a single conductive fiber bundle, and the single conductive fiber bundle has a surface nickel plating layer.

4. The device for preventing electric corrosion of motor bearings according to claim 1, characterized in that: The conductive mounting seat has an external hexagonal mounting portion.

5. The device for preventing electric corrosion of motor bearings according to claim 1, characterized in that: The conductive mounting seat has a central cavity, and the cavity wall of the central cavity has symmetrically arranged and extrudable thin-walled parts for riveting and fixing the conductive fiber bundle.

6. A motor for preventing electrical corrosion of bearings, comprising a stator housing, a rotor, a front bearing, a rear bearing, a motor front cover and a motor rear cover, characterized in that: The motor rear cover has a seat cavity, and the seat cavity is used to place the device for preventing electric corrosion of motor bearings according to any one of claims 1 to 5.

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