Motor assembly and method of manufacturing the same

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.

A motor assembly comprising:

• a motor;
• and
• an impeller coupled to a rotation shaft of the motor,
• wherein the impeller comprises:
• a body comprising a blade, and a ring-shaped groove formed in a surface of the body;
• a cover member configured to cover the groove;
• a plurality of balls disposed inside the groove;
• and
• a fixing member configured to fix the balls so that positions of the balls are maintained inside the groove,
• 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, and
• 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.

A vacuum cleaner comprising a motor assembly, wherein:

• the motor assembly comprises a motor and an impeller coupled to a rotation shaft of the motor, and
• the impeller comprises:
• a body including a ring-shaped groove formed in a surface of the body;
• a cover member configured to cover the groove;
• a plurality of balls disposed inside the groove;
• and
• a fixing member configured to fix the balls inside the groove,
• 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, and
• 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.