| 摘要 |
PROBLEM TO BE SOLVED: To reduce contact of liners with a recording medium, thereby reducing driving torque by welding the liners to the internal surfaces of shells so that the liners do not build up even in the state of moisture absorption. SOLUTION: Regarding the fixing of the liners 5, 6 by an ultrasonic welding process using a welding horn 20 to respective internal surfaces of the upper and lower shells 1, 2 placed opposite to the recording medium 4 rotatably housed into a case C constituted of the upper shell 1 and the lower shell 2, a welding pattern with ruggedness is formed on the entire surface along the shapes of the liners 5, 6 on the tip end face 20a of the welding horn 20, and the liners 5, 6 are welded over the entire surface by this welding pattern. |
