WO2023155418A1

WO2023155418A1 - Electric brush device for preventing electrical corrosion of motor bearing, and motor

Info

Publication number: WO2023155418A1
Application number: PCT/CN2022/116693
Authority: WO
Inventors: 王昆; 孙韬; 王宗浩; 王朋; 孙明扬
Original assignee: 上海纳铁福传动系统有限公司
Priority date: 2022-02-15
Filing date: 2022-09-02
Publication date: 2023-08-24

Abstract

The present invention relates to the technical field of motors, and relates in particular to an electric brush device for preventing electrical corrosion of a motor bearing and a motor comprising the electric brush device. The electric brush device comprises a motor rotating shaft, a motor housing, a ball body, an electric brush assembly, and a grounding support frame; one end of the motor rotating shaft is internally hollow and a cavity is formed; the ball body is arranged in the cavity and makes contact with the motor rotating shaft; the grounding support frame is connected to the motor housing; one end of the electric brush assembly is connected to the grounding support frame, and the other end abuts against the ball body; the motor rotating shaft, the ball body, the electric brush assembly, the grounding support frame, and the motor housing are sequentially connected to form an electrical conduction path, causing equal potential to be formed between the motor rotating shaft and the motor housing. An equal potential design between the motor rotating shaft and the motor housing is implemented by means of constructing the motor rotating shaft-ball body-electric brush assembly-grounding support frame-motor housing electrical conduction path, and thereby electrical corrosion and failure of a motor bearing is prevented, and the present invention has the advantages of having a simple and effective overall structure and being low-cost.

Description

Brush device and motor for preventing electrical corrosion of motor bearing

technical field

The invention relates to the technical field of motors, in particular to a brush device for preventing electric corrosion of motor bearings and a motor including the brush device.

Background technique

When the motor driven by frequency conversion is powered by the inverter system, it will generate high-frequency common-mode voltage, which will form a potential difference between the motor shaft and the motor housing, and because the bearing between the motor shaft and the motor housing is for Lubrication with insulating lubricating oil causes nowhere to release the potential difference. The common mode voltage forms a shaft voltage between the inner and outer rings of the bearing through the stray capacitance. When the shaft voltage is greater than the maximum voltage that the bearing capacitance can withstand, the shaft voltage The discharge of the lubricating oil film that is easy to break down the bearing produces shaft current. During the discharge process, pits will be formed on the raceways of the inner and outer rings of the bearing, and the shape of the washboard pattern will eventually appear due to the vibration of the bearing during operation, resulting in bearing NVH ( Noise, vibration and acoustic roughness) become worse, and even shorten the service life of the bearing. Therefore, solving bearing electrocorrosion is of great significance to the service life and reliability of the motor. Although existing solutions such as ceramic ball bearings and carbon fiber brushes can effectively prevent the occurrence of electrical corrosion of bearings, the relative cost is relatively high.

Contents of the invention

The technical problem to be solved by the present invention is to provide a low-cost brush device for preventing electrical corrosion of motor bearings, so as to overcome the above-mentioned defects in the prior art.

In order to solve the above technical problems, the present invention adopts the following technical solutions:

The invention provides a brush device for preventing electrical corrosion of motor bearings, which includes a motor shaft, a motor housing, a sphere, a brush assembly and a grounding bracket, one end of the motor shaft is hollow to form a cavity, and the sphere is arranged in the cavity And contact with the motor shaft, the grounding bracket is connected with the motor housing, one end of the brush assembly is connected with the grounding bracket, and the other end is abutted on the sphere; the motor shaft, the sphere, the brush assembly, the grounding bracket and the electric The casings of the motor are connected in sequence to form a conductive path, so that an equipotential is formed between the rotating shaft of the motor and the casing of the motor.

Preferably, a seat hole is formed on the inner side wall of the motor housing, and one end of the motor shaft provided with a concave cavity extends into the seat hole, and the inner peripheral side wall of the seat hole and the outer peripheral side wall of the motor shaft are sealed by a rotary seal. One end of the grounding bracket is sealingly connected with the outer side wall of the motor casing, and the other end passes through the motor casing and the seat hole and extends into the cavity.

Preferably, a sealing gasket is used to seal the grounding bracket and the outer side wall of the motor housing.

Preferably, one end of the grounding bracket is connected to the inner side wall of the motor casing, and the other end extends into the cavity of the motor shaft, and the inner peripheral side wall of the concave cavity and the outer peripheral side wall of the grounding bracket are sealed by a rotary seal. parts are sealed.

Preferably, the sphere is a steel ball, and the surface of the steel ball is mirror-polished.

Preferably, the ball is in interference fit with the cavity of the motor shaft.

Preferably, a mounting hole is formed through the inside of the grounding bracket, and the brush assembly is arranged in the mounting hole.

Preferably, the brush assembly includes a screw, a brush, a brush braid and a spring, the screw is threadedly connected to the grounding bracket, the brush and the screw are electrically connected through the brush braid, and the spring elastically presses between the screw and the brush and will The brushes are pressed against the sphere.

The present invention also provides a motor, including the above-mentioned brush device for preventing electrical corrosion of motor bearings.

Compared with prior art, the present invention has remarkable progress:

The brush device for preventing electrical corrosion of motor bearings of the present invention realizes the equipotential design between the motor shaft and the motor housing by constructing the conductive path of the motor shaft-ball-brush assembly-grounding bracket-motor housing. This realization prevents electric corrosion failure of the motor bearing, and has the advantages of simple and effective overall structure and low cost.

Description of drawings

Fig. 1 is a schematic cross-sectional structure diagram of an embodiment of a brush device for preventing electrical corrosion of motor bearings according to an embodiment of the present invention.

Fig. 2 is a schematic cross-sectional structure diagram of another embodiment of the brush device for preventing electrical corrosion of motor bearings according to the embodiment of the present invention.

Fig. 3 is a schematic structural view of a brush assembly in preventing electrical corrosion of motor bearings according to an embodiment of the present invention.

Wherein, the reference signs are explained as follows:

1 Motor shaft

11 concave cavity

2 Motor housing

21 Internal cavity

22 seat hole

3 sphere

4 Brush assembly

41 screw

42 Brushes

43 Brush braid

44 spring

5 ground bracket

51 Mounting hole

6 Rotary seal

Detailed ways

The specific implementation manners of the present invention will be described in further detail below in conjunction with the accompanying drawings. These embodiments are only used to illustrate the present invention, not to limit the present invention.

In the description of the present invention, it should be noted that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", " The orientations or positional relationships indicated by "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying Describes, but does not indicate or imply that the device or element referred to must have a specific orientation, be constructed in a specific orientation, and operate in a specific orientation, and therefore should not be construed as limiting the invention. In addition, the terms "first" and "second" are used for descriptive purposes only, and should not be understood as indicating or implying relative importance.

In the description of the present invention, it should be noted that unless otherwise specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection. Connected, or integrally connected; it can be mechanically connected or electrically connected; it can be directly connected or indirectly connected through an intermediary, and it can be the internal communication of two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention according to specific situations.

In addition, in the description of the present invention, unless otherwise specified, "plurality" means two or more.

As shown in Figures 1 to 3, an embodiment of the brush device for preventing electric corrosion of motor bearings according to the present invention.

Referring to FIG. 1 and FIG. 2 , the brush device for preventing electrical corrosion of motor bearings in this embodiment includes a motor shaft 1 , a motor housing 2 , a ball 3 , a brush assembly 4 and a grounding bracket 5 .

Wherein, one end of the motor shaft 1 is hollow to form a concave cavity 11. In a preferred embodiment, the inside of the motor shaft 1 can be penetrated in the axial direction, and the concave cavity 11 is the inner axial direction of the motor shaft 1. Through hole.

The inside of the motor housing 2 is hollow to form an inner cavity 21 , the motor shaft 1 is disposed in the inner cavity 21 inside the motor housing 2 , and the motor shaft 1 is rotatably supported in the motor housing 2 through bearings.

The ball 3 is arranged in the cavity 11 of the motor shaft 1 , and the ball 3 is in contact with the motor shaft 1 . Preferably, the ball 3 has an interference fit with the cavity 11 of the motor shaft 1 , so that the ball 3 is fixedly installed in the cavity 11 of the motor shaft 1 and keeps in contact with the motor shaft 1 .

The grounding bracket 5 is connected to the motor housing 2 , one end of the brush assembly 4 is connected to the grounding bracket 5 , and the other end of the brush assembly 4 abuts against the sphere 3 . The motor shaft 1, the sphere 3, the brush assembly 4, the grounding bracket 5 and the motor housing 2 are connected in sequence to form a conductive path, and the electric charge generated by the motor shaft 1 due to common mode voltage and shaft current can flow through this conductive path, so that the motor An equipotential is formed between the rotating shaft 1 and the motor housing 2, thereby preventing electric corrosion failure of the motor bearing.

The brush device for preventing electrical corrosion of motor bearings in this embodiment realizes motor shaft 1 and motor housing 2 by constructing a conductive path of motor shaft 1-ball 3-brush assembly 4-grounding bracket 5-motor housing 2 The equipotential design between them can prevent the electrical corrosion failure of the motor bearing, and has the advantages of simple and effective overall structure and low cost.

In this embodiment, the sphere 3 has electrical conductivity. Preferably, the ball 3 can be a steel ball, and the surface of the steel ball is preferably mirror polished, which can reduce the wear of the brush assembly 4 abutting against the ball 3 and the friction loss of the motor, which is beneficial to prolong the service life of the motor and reliability.

In this embodiment, there are the following two ways of assembling the grounding bracket 5 and the motor housing 2 .

Referring to FIG. 1 , in one embodiment, a seat hole 22 is formed on the inner side wall of the motor housing 2 , and the seat hole 22 and the motor shaft 1 are preferably arranged coaxially. One end of the motor shaft 1 provided with the concave cavity 11 protrudes into the seat hole 22 , and the inner peripheral side wall of the seat hole 22 and the outer peripheral side wall of the motor shaft 1 are sealed by a rotary seal 6 . One end of the grounding bracket 5 is located outside the motor housing 2 and is sealingly connected to the outer side wall of the motor housing 2 , and the grounding bracket 5 and the outer side wall of the motor housing 2 are preferably sealed by a gasket. The grounding bracket 5 and the outer side wall of the motor housing 2 can be mechanically connected and fixed by bolts, and a gasket can be arranged between the grounding bracket 5 and the outer side wall of the motor housing 2 for sealing, and a sealant can also be filled. Make a seal. The other end of the ground bracket 5 passes through the motor housing 2 and the seat hole 22 and extends into the cavity 11 . The brush assembly 4 is arranged inside the grounding bracket 5 , one end of the brush assembly 4 is fixedly installed inside the grounding bracket 5 , and the other end of the brush assembly 4 abuts against the sphere 3 . Thus, the static sealing between the grounding bracket 5 and the inner cavity 21 of the motor housing 2 is realized through the sealed connection between the grounding bracket 5 and the outer side wall of the motor housing 2, and through the inner peripheral side wall of the seat hole 22 and the motor A rotary seal 6 is provided between the outer peripheral side walls of the rotating shaft 1 to realize the dynamic sealing between the brush assembly 4 and the inner cavity 21 of the motor housing 2, and the wear debris of the brush assembly 4 can be prevented from entering the motor housing through the seal 2. The inner cavity 21 contacts the charged stator assembly and affects the insulation performance of the motor system, which is beneficial to prolong the service life and reliability of the motor. At the same time, installing one end of the grounding bracket 5 on the outer side wall of the motor housing 2 can directly replace the gradually worn brush assembly 4 from the outside, which is also beneficial to prolong the service life and reliability of the motor.

Referring to FIG. 1 , in another embodiment, one end of the grounding bracket 5 is connected to the inner side wall of the motor housing 2, and the other end of the grounding bracket 5 extends into the cavity 11 of the motor shaft 1, and the cavity 11 The seal between the inner peripheral side wall and the outer peripheral side wall of the ground support 5 is sealed by a rotary seal 6 . The brush assembly 4 is arranged inside the grounding bracket 5 , one end of the brush assembly 4 is fixedly installed inside the grounding bracket 5 , and the other end of the brush assembly 4 abuts against the sphere 3 . Thus, one end of the grounding bracket 5 is installed and fixed on the inner side wall of the motor housing 2, and the static seal between the two is no longer needed; The rotary seal 6 is arranged between the side walls to realize the dynamic sealing between the brush assembly 4 and the inner cavity 21 of the motor housing 2, which can prevent the wear debris of the brush assembly 4 from entering the inner cavity 21 of the motor housing 2 Contact with the live stator assembly affects the insulation performance of the motor system, which is beneficial to prolong the service life and reliability of the motor.

In this embodiment, referring to FIG. 1 and FIG. 2 , preferably, an installation hole 51 is formed through the inside of the grounding bracket 5 , and the brush assembly 4 is disposed in the installation hole 51 .

Referring to Fig. 3, preferably, the brush assembly 4 includes a screw 41, a brush 42, a brush braid 43 and a spring 44, the screw 41 is threadedly connected with the grounding bracket 5, and the brush 42 and the screw 41 are electrically connected through the brush braid 43 The spring 44 is elastically pressed between the screw 41 and the brush 42, and the screw 41 can be tightened to press the brush 42 against the sphere 3 through the spring 44, so that the brush 42 and the sphere 3 maintain abutting contact. Referring to Fig. 1 and Fig. 2, preferably, the screw 41, the brush 42, the brush braid 43 and the spring 44 of the brush assembly 4 are all accommodated in the mounting hole 51 inside the grounding bracket 5, and the mounting hole inside the grounding bracket 5 51 is set coaxially with the motor shaft 1, the screw 41 is located in the end of the mounting hole 51 away from the sphere 3 and is threadedly connected with the mounting hole 51, the brush 42 is located in the end of the mounting hole 51 close to the sphere 3, and the brush 42 is far away from the screw One end of 41 protrudes from the mounting hole 51 and abuts against the ball 3 .

Based on the above-mentioned brush device for preventing electrical corrosion of motor bearings, this embodiment also provides a motor. The motor of this embodiment includes the above-mentioned brush device for preventing electrical corrosion of motor bearings.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the technical principle of the present invention, some improvements and replacements can also be made, these improvements and replacements It should also be regarded as the protection scope of the present invention.

Claims

A brush device for preventing electrical corrosion of motor bearings, characterized in that it includes a motor shaft (1), a motor housing (2), a sphere (3), a brush assembly (4) and a grounding bracket (5). One end of the motor shaft (1) is hollow to form a concave cavity (11), the ball (3) is arranged in the concave cavity (11) and is in contact with the motor shaft (1), and the grounding bracket (5) Connected to the motor housing (2), one end of the brush assembly (4) is connected to the grounding bracket (5), and the other end abuts against the sphere (3) ; the motor shaft (1), the sphere (3), the brush assembly (4), the grounding bracket (5) and the motor housing (2) are sequentially connected to form a conductive path, so that the An equipotential is formed between the motor rotating shaft (1) and the motor housing (2).
The brush device for preventing electrical corrosion of motor bearings according to claim 1, characterized in that, a seat hole (22) is formed on the inner side wall of the motor housing (2), and the motor shaft (1) One end provided with the concave cavity (11) extends into the seat hole (22), and the inner peripheral side wall of the seat hole (22) and the outer peripheral side wall of the motor shaft (1) pass through The rotary seal (6) is sealed, and one end of the grounding bracket (5) is in sealing connection with the outer side wall of the motor housing (2), and the other end passes through the motor housing (2) and the The seat hole (22) extends into the concave cavity (11).
The brush device for preventing electrocorrosion of motor bearings according to claim 2, characterized in that, a seal is used between the grounding support (5) and the outer side wall of the motor housing (2).
The brush device for preventing electrical corrosion of motor bearings according to claim 1, wherein one end of the grounding bracket (5) is connected to the inner side wall of the motor housing (2), and the other end protruding into the cavity (11) of the motor shaft (1), and a rotary seal ( 6) Seal.
The brush device for preventing electrical corrosion of motor bearings according to claim 1, characterized in that the ball (3) is a steel ball, and the surface of the steel ball is mirror polished.
The brush device for preventing electrical corrosion of motor bearings according to claim 1, characterized in that the ball (3) is in interference fit with the cavity (11) of the motor shaft (1).
The brush device for preventing electrical corrosion of motor bearings according to claim 1, characterized in that, an installation hole (51) is formed through the inside of the grounding bracket (5), and the brush assembly (4) is arranged on the installation inside the hole (51).
The brush device for preventing electrical corrosion of motor bearings according to claim 1, characterized in that, the brush assembly (4) includes screws (41), brushes (42), brush braids (43) and springs (44 ), the screw (41) is threadedly connected with the grounding bracket (5), the brush (42) is electrically connected to the screw (41) through the brush braid (43), and the spring (44) Elastically press between the screw (41) and the brush (42) and press the brush (42) tightly on the sphere (3).
A motor, characterized by comprising the brush device for preventing electrical corrosion of motor bearings according to any one of claims 1 to 8.