Patent ID: 7649291

Claim:
A limit structure for a motor spindle, comprising: a rotor; a spindle having one end stationarily coupled to a center of said rotor and the other end being a nose having a necking with a reduced diameter; a base having a shaft tube and a stator set, wherein said shaft tube has a limit member and a bearing disposed therein for rotationally supporting said spindle in said bearing, said limit member has an inner wall forming a through hole in said limit member and a plurality of limit protrusions extended from the inner wall to a center of said through hole, said plurality of limit protrusions arranged to receive said nose and to snap said necking of said spindle to limit an axial displacement thereof, each of said plurality of limit protrusions forms a non-vertical included angle respectively with said inner wall in a tilted manner by constituting a larger included angle between a top side of each said limit protrusion and said inner wall and a smaller included angle between a bottom side of each said limit protrusion and said inner wall, said spindle is inserted in said through hole through said top side having larger included angle first and then through said bottom side having smaller included angle; an abrasive pad disposed inside said shaft tube, wherein said spindle urges against the abrasive pad; and a position member corresponding to an opening at a top end of the shaft tube, wherein the position member caps onto the shaft tube so as to steadily position the bearing and the limit member inside the shaft tube, wherein a groove is formed between adjacent limit protrusions, and each said limit protrusion has a snap hole centrally formed therein for inserting said nose of said spindle in said snap hole, and wherein each limit protrusion has a top surface and a bottom surface opposing the top surface, the larger included angle is formed between the top surface and the inner wall, and the smaller included angle is formed between the bottom surface and the inner wall.