Hollow shaft motor

A hollow shaft motor, comprising:

• a motor housing (11) having a cylindrical shape;
• a housing cover assembly (12) coupled to an upper portion of the motor housing (11);
• a rear cover (15) coupled to a lower portion of the motor housing (11);
• a stator assembly (20) located in the motor housing (11) and in a lower portion of the housing cover assembly (12);
• a rotor assembly (30) located in the stator assembly (20) to rotate,
• wherein the housing cover assembly (12) comprises a housing cover (121), and the housing cover (121) is formed by insert injection molding while placing a press ring (122), a bus bar (123) and a sleeve (124) in a mold,
• wherein the sleeve (124) has a cylindrical shape vertically penetrated, and a flange (124A) radially extended is formed in an upper portion of the sleeve (124),
• wherein the flange (124A) is located in an upper portion of a cavity (121C) and surrounded by a plastic resin forming the housing cover (121),
• wherein a ball nut (17) and a piston that move up and down by a rotation of a screw shaft (10) are located inside the sleeve (124);
• and
• an upper bearing (13) comprising an outer race and an inner race, wherein as the outer race is press-fitted and supportedly coupled to an inner side of the press ring (122), and the inner race is supported by an upper bearing coupling groove (312) formed on an outer circumference of a top of a hollow shaft housing (311) that constitutes a hollow shaft (31), the upper bearing (13) supports a rotation of the hollow shaft (31).