Brushless DC motor with improved ground structure

Abstract

The brushless DC motor according to the present invention, comprises: a housing 10 comprising a stator 15 in the inside, and having a hollow part 11 in which a rotor 20 coupled to a shaft 21 is positioned in the middle part; an upper bearing 22 coupled to an output side of the shaft 21 to rotatably support the shaft; an upper bearing cover 31 accommodating the upper bearing 22 and covering the hollow part 11; a lower bearing 23 coupled to a lower end of the shaft 21 to rotatably support the shaft; a lower bearing holder 32 accommodating the lower bearing 23 and coupled to a middle lower part of the housing 10; and a first grounding member 50 having an upper end part 50a bendingly coupled to an outer part of the upper bearing cover 31, and a lower end part 50b coupled to a middle part of the lower bearing holder 32, so as to make the upper bearing cover 31 and the lower bearing holder 32 electrically equipotential.

Description

technical field [0001] The invention relates to a grounding structure of an electric machine. More specifically, the present invention relates to a motor with a grounding structure. By improving the grounding structure, it can more effectively prevent electrolytic corrosion of bearings, improve performance and durability, and has the characteristics of small vibration and low noise. Background technique [0002] Generally, an electric machine includes a stator and a rotor. The rotor rotates under the influence of the magnetic field created by the stator. The shaft coupled to and rotating with the rotor has bearings to support the rotation of the shaft mounted above and below the rotor. [0003] Typically, such motors are controlled by drive circuits. When the drive circuit is running, the potential difference between the upper and lower bearings, or the axial current due to another cause, causes electrolytic corrosion of the bearings. When the motor is running under elec...

AI Technical Summary

Problems solved by technology

In the prior art, an effective ground connection is made between the upper and lower bearing caps, but since it has a structure that inserts the bearings outside the upper and lower bearing caps, the two bearings are easily exposed on the outside

In particular, due to the structure in which one end of the metal member for grounding is slightly in contact with the lower bearing cap, the grounding member is likely to be isolated, and therefore there may be a problem that the electrolytic corrosion of the bearing cannot be effectively prevented

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