| 摘要 |
A rim ( 10 ) is produced by a production process including a step (A) of bending a workpiece ( 11 ) to bring end faces of the workpiece into contact with each other, a step (B) of forming a circular cylinder body ( 12 ) by joining the end faces brought to be in contact with each other, a step (C) of inspecting a joint portion ( 13 ) of the circular cylinder body ( 12 ), a step (D) of forming a drop portion ( 16 ), subsiding toward the inner peripheral wall ( 15 ) side, in an outer peripheral wall ( 14 ) of the circular cylinder body ( 12 ), a by bending both end portions of the circular cylinder body ( 12 ), a step (F) of forming hump portions ( 20 ) by pressing the circular cylinder body ( 12 ) from the inner peripheral wall ( 15 ) side to raise the outer peripheral wall ( 14 ), and a step (G) for forming a valve hole ( 22 ) and water drain holes ( 24 ) in the drop portion ( 16 ) and the curl portions ( 18 ). The rim ( 10 ) and a disk ( 102 ) that is separately produced are welded to form a wheel ( 122 ).
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