| CPC H02K 15/165 (2013.01) [H02K 7/16 (2013.01)] | 14 Claims |
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6. A method of manufacturing a motor assembly comprising a motor and an impeller coupled to a rotation shaft of the motor, the method comprising:
disposing a plurality of balls in a ring-shaped groove formed in a surface of the impeller;
disposing a transparent cover to cover the groove and to allow identifying a position of the balls inside the groove;
rotating the impeller at a speed greater than a resonant rotation speed of the impeller to move the balls to a compensation position for compensating for an eccentricity in the motor assembly;
identifying the compensation position of the balls through the transparent cover by rotating the impeller at the speed greater than the resonant rotation speed, using at least one of a high-speed camera or a stroboscope; and
fixing the balls so that the balls are maintained at the compensation position in the groove,
wherein the fixing of the balls at the compensation position comprises:
removing the transparent cover after stopping the impeller;
moving the balls to the compensation position in the groove; and
fixing the balls at the compensation position using a fixing member by covering the groove with a cover member in which the fixing member is formed,
wherein the fixing member comprises a plurality of protrusions that protrude from an inner surface of the cover member and are arranged at equal intervals in a circumferential direction,
wherein a pair of protrusions adjacent to each other among the plurality of protrusions are formed on both sides of the balls to limit positional movement of the balls,
wherein a gap between the pair of protrusions is greater than or equal to a radius of the balls and less than or equal to a diameter of the balls, and
wherein a height of a protrusion of the pair of protrusions from an inner surface of the cover member is greater by a length of 10% to 20% of the diameter of the balls than a difference between a height from a bottom surface of the groove to an inner surface of the cover member and the diameter of the balls.
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