| 摘要 |
PROBLEM TO BE SOLVED: To prevent the destruction of a rotor magnet and ensure practical fixing force by forming a portion which is not brought into contact with a rotor shaft inside the hollow portion in the rotor magnet, and filling the space formed by the portion and the rotor shaft with an adhesive. SOLUTION: The length of a press fit portion is adjusted (so that the relation T/5<=t<=4T/5 will hold, where t is a press fit length and T is the height of a rotor magnet 21), and a rotor shaft 22 is press fit in a cylindrical rotor magnet 21, to the extent that the rotor shaft is fixed preliminarily. Then an adhesive 24 is made to penetrate into the gap between the rotor magnet 21 and the rotor shaft 22 through vacuum impregnation to bond them together. If the rotor magnet 21 is a bond magnet, it is essentially low in mechanical strength. Therefore, it is coated by metal plating, organic film coating or the like. In case of a metal plate film 23, Ni-P is coated by electroless plating to a thickness of not less than 10μm, in order that the plate thickness on the inner circumference of the cylinder matches with that of the outer circumference. The bonding margin (b-c), or the gap between the rotor shaft 22 and the rotor magnet 21 has only to be 2μm or above, and the length of the bonded portion (T-t) has only to be 50μm or above.
|
