CN1259765C - A device that can prevent electrostatic discharge of motor stator and rotor - Google Patents

Abstract

The invention discloses a device capable of preventing electrostatic discharge of the motor stator and rotor. It is provided with a threaded through hole radially on the outer circumference of the motor end cover, and the end of the through hole is provided with a screw thread. A steel ball, a metal spring and a compression screw are arranged, the steel ball is located at the inner end of the through hole and is in contact with the main shaft, the compression screw is connected with the threaded section provided at the end of the through hole, and the metal spring is located at the steel ball and the compression screw. between the screws. The invention has a simple and reliable structure, is easy to use and can effectively avoid electrostatic discharge damage faults of the stator and rotor of the motor.

Description

A device that can prevent electrostatic discharge of motor stator and rotor

Technical Field The present invention belongs to the field of motors, and in particular relates to a device that can prevent electrostatic discharge of motor stators and rotors.

Background technology The motor is a kind of equipment widely used in industrial and agricultural production at present; during the working process of the motor, the phenomenon of charge accumulation will occur on the surface of the motor stator and rotor. When the charge accumulates to a certain extent, it will Electrostatic discharge occurs. The parts where electrostatic discharge usually occurs are motor bearings and motor encoders.

At present, steel bearings are widely used in motor bearings. The lubricating oil film on the bearing surface has an insulating effect. However, under the condition of high-voltage electrostatic discharge, the oil film is easily broken down and causes electrical corrosion on the bearing surface and damages it. When the motor bearing is supported by ceramic bearings, etc., due to the insulating effect of ceramic balls, electrostatic discharge is not easy to occur at the bearing part, but will be transferred to the encoder gear fixed on the motor rotor and the encoder seat fixed to the motor frame. between, resulting in damage to the encoder. In recent years, the application of AC frequency conversion speed regulation technology in the field of motors has become very common. High-order electromagnetic harmonics caused by frequency conversion technology greatly increase the probability of induced static electricity on the stator and rotor of the motor. According to statistics, at present, bearing failures caused by electrostatic discharge have accounted for more than 10% of all bearing failures, and are growing continuously; while encoder failures caused by electrostatic discharge account for a higher probability of all encoder failures.

In order to avoid electrostatic discharge of the stator and rotor of the motor on bearings, encoders and other parts, the common solution is to ground the rotor of the motor, and use a conductive lubricant for the bearings. However, conductive lubricants often wear the bearing due to the metal particles contained in it, resulting in shortened bearing life. Another traditional way to avoid electrostatic discharge is to ground the rotating shaft through carbon brushes. However, carbon brushes are prone to pollution and the surrounding environment needs to be cleaned during replacement, which makes it very inconvenient to replace carbon brushes. Now a method of eliminating the induced voltage by shielding the stator winding of the motor is proposed to reduce the electrostatic discharge, but because of the high cost of this method, it is difficult to realize in engineering.

Summary of the Invention The technical problem to be solved by the present invention is to provide a device that can prevent electrostatic discharge of motor stator and rotor with simple structure and easy operation.

The technical scheme adopted by the present invention to solve the above-mentioned technical problems is: it is provided with a threaded through hole radially on the outer circumference of the motor end cover, the end of the through hole is provided with a thread, and a steel pipe is set in the through hole. Ball, metal spring and compression screw, the steel ball is located at the inner end of the through hole and is in contact with the main shaft, the compression screw is connected with the threaded section set at the end of the through hole, and the metal spring is located between the steel ball and the compression screw between.

As a further improvement of the present invention, a metal gasket is arranged between the steel ball and the metal spring.

There may be one or more than one threaded through holes.

The threaded through hole is located below the installation position of the motor end cover.

The beneficial effect of the present invention is that: the present invention arranges steel balls, metal springs and compression screws in the threaded through holes opened radially on the outer circumference of the motor end cover, and the steel balls are always kept in contact with the main shaft under the action of the spring force. It is in the state of conductor contact; since the motor rotor is in contact with the main shaft as a conductor, and the motor stator is in contact with the motor frame, the spindle actually forms a circuit between the motor stator and rotor by contacting the steel ball, spring, motor end cover and the motor frame . At the same time, since the motor frame is usually grounded, the static electricity on the motor rotor and the motor stator can be released directly through the grounding conductor, thus avoiding the high-voltage electrostatic discharge phenomenon between the motor stator and rotor. The invention has a simple and reliable structure, is easy to use, and can effectively avoid electrostatic discharge damage to the stator and rotor of the motor.

The invention can realize the function of avoiding electrostatic discharge of the stator and rotor of the motor by directly replacing the end cover of the original motor, and can also be completed by transforming and processing the end cover of the original motor, which is very convenient to realize.

Description of drawings

Fig. 1 is the structural schematic front view of the embodiment of the present invention:

Fig. 2 is A-A sectional view of Fig. 1;

Fig. 3 is a structural schematic view of the present invention installed on a motor.

Each label in the figure means:

1. Motor end cover, 11. Through hole, 2. Steel ball, 3. Metal spring,

4. Compression screw, 5. Metal gasket, 6. Main shaft, 7. Motor frame,

8. Motor stator, 9. Motor rotor.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in Figures 1, 2, and 3, the device for preventing electrostatic discharge of the motor stator and rotor according to the present invention is to provide a threaded through hole 11 radially on the outer circumference of the motor end cover 1, One or more holes can be arranged along the circumference. In order to ensure the reliability of the contact between the motor rotor 9 and the steel ball 2 conductors, multiple holes can be arranged. In this embodiment, there are two holes. The end of the through hole 11 is provided with threads, and a steel ball 2, a metal spring 3 and a compression screw 4 are arranged in the through hole 11. The steel ball 2 is located at the inner end of the through hole 11 and is in contact with the main shaft 6, and the compression screw 4 Connected with the threaded section provided at the end of the through hole 11, the metal spring 3 is located between the steel ball 2 and the compression screw 4, and the steel ball 2 is always in conductor contact with the metal spindle 6 under the action of the spring force; the spring The force is achieved by adjusting the depth of the compression screw 4 screwed into the through hole 11 of the motor end cover 1 and changing the compression of the metal spring 3 . A metal washer 5 can also be arranged between the steel ball 2 and the metal spring 3 to facilitate the rolling of the steel ball 2 .

The orientation of the machined threaded through hole 11 on the outer circumference of the motor end cover 1 can be arbitrarily staggered with the positions of the fastening screw holes of the motor end cover 1 . As shown in FIG. 3 , it is preferably installed below the installation position of the motor end cover 1 , so that the replacement of the steel ball 2 and the metal spring 3 can be easily completed without removing the motor end cover 1 .

The working principle of the present invention is: the steel ball 2 is always in conductor contact with the metal main shaft 6 under the action of the spring force, the motor rotor 9 is in conductor contact with the main shaft 6, the motor stator 8 is in conductor contact with the motor frame 7, and the main shaft 6 By contacting the steel ball 2, the metal spring 3, the motor end cover 1 and the motor frame 7, the motor stator and rotor actually form a circuit (see Figure 3). At the same time, since the motor base 7 is usually grounded, the static electricity on the motor rotor 9 and the motor stator 8 can be directly released through the ground conductor, thereby avoiding the high-voltage electrostatic discharge phenomenon between the motor stator and rotor.

When the present invention is used, it can directly replace the original motor end cover, and can also be realized by transforming and processing the original motor end cover.

Claims (4)

1. A device that can prevent electrostatic discharge of the motor stator and rotor is characterized in that it is provided with a threaded through hole (11) radially on the outer circumference of the motor end cover (1), and the through hole (11) The end is provided with threads, and a steel ball (2), a metal spring (3) and a compression screw (4) are arranged in the through hole (11), and the steel ball (2) is located at the inner end of the through hole (11) and is connected with the The main shaft (6) is in contact, and the compression screw (4) is connected with the threaded section provided at the end of the through hole (11), and the metal spring (3) is positioned between the steel ball (2) and the compression screw (4). 2. The device for preventing electrostatic discharge of motor stator and rotor according to claim 1, characterized in that a metal gasket (5) is arranged between the steel ball (2) and the metal spring (3). 3. The device for preventing electrostatic discharge of motor stator and rotor according to claim 1 or 2, characterized in that there are one or more than one threaded through holes (11). 4. The device for preventing electrostatic discharge of motor stator and rotor according to claim 1 or 2, characterized in that the threaded through hole (11) is located below the installation position of the motor end cover (1).

Images