STRUCTURE FOR PREVENTING ELECTRIC CORROSION OF BALL BEARING PROVIDED WITH OUTER-ROTOR TYPE BLDC MOTOR

摘要

Disclosed is a structure for preventing electric corrosion of a ball bearing provided in an outer-rotor type BLDC motor that is composed of a motor shaft; a ball bearing including an inner race in which the motor shaft is inserted, an outer race rotating relative to the inner race, and a ball interposed between the inner race and the outer race; a bearing bracket in which the outer race of the ball bearing is inserted; a stator core which is installed along the outer circumference of the bearing bracket and around which a coil is wound; a rotor connected to the motor shaft and having permanent magnets which are magnetized with N poles and S poles spaced part from an outer circumferential surface of the stator rotor and which are alternately arranged in the inner circumference of the rotor; a hall sensor sensing magnetic poles of the permanent magnets; a drive circuit receiving a signal from the hall sensor and applying current with different polarities to the coil by turns. The structure of preventing electric corrosion of the ball bearing of the outer-rotor type BLDC motor, according to the present invention, includes at least one penetration hole formed at an outer circumferential surface of the motor shaft disposed in the inner race of the ball bearing; and an insulating material coating the outer circumferential surface of the motor shaft, wherein the penetration hole is filled with a portion of the insulating material.