| 摘要 |
PROBLEM TO BE SOLVED: To provide a cutting method enables to cutting a high precision motor hub in one step, although the motor hub is in a form permitting a process only in a weak holding force, enables to reduce production cost. SOLUTION: When cutting a blank member 41 designed for a hub which has a hub body 32 supported by a shaft pole unuvesally rotatively through a ball bearing, and a disk holding barrel 36 which is protrusively provided around peripheral part of the hub body 32 and a yoke attachment surface 36b formed around inner surface, chucks C are radially thrusted against a bore diameter holding surface 36d, which is an approximate side of the yoke attachment surface 36b to the hub body 32, and are respectively holded by abutting front edge grippers Ca to radial load supporting places R at perimeterically equal 8 places and, also diretional load toward shaft centre is supported by radially thrusting grippers Cb at rear anchor side of the chucks C against thrust direction supporting places S at 4 places, which is fewer than the radial load supporting place R, by an edge face 36e of the disk holding barrel 36, then the disk holding surface 36a and the hub body 32 are cut.
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