| 摘要 |
PROBLEM TO BE SOLVED: To suppress swelling of a rotor frame due to high-speed rotation, and attain a motor with high printing accuracy and low vibration without increasing unbalancing by forming an annular collar at the outer periphery part of the rotor frame, and fixing a ring which is of concentric shape with the rotor frame on the collar. SOLUTION: This motor is provided with an annular collar 11 formed at the outer periphery part of a rotor frame 7. On the collar 11, a ring 12 of concentric shape with the rotor frame 7 is fixed. The circumferential thickness of the ring 12 is much larger than that of the rotor frame 7. In this structure, the outer periphery of the rotor frame 7 is retained by the ring 12 having much higher strength than the rotor frame 7, thus it is possible to suppress swelling of the rotor frame 7 due to high-speed rotation. Unbalancing correction at the lower surface of the rotor is conducted by cutting the upper surface of the ring 12. It is thus possible to eliminate an increase of unbalancing. |
