| 摘要 |
PURPOSE:To facilitate the forming of salient strip sections for obtaining suitable retaining forces accommodated to respective fitting component parts, by forming the cross-section-wedge-formed salient strip sections of different levels along the longitudinal direction at the same time, with one-time press-forming. CONSTITUTION:The cross-sectional area of a metallic mold 7 is U-formed, and a step difference G between the forming surface 9A at a fitting position A with a commutator and a one-side oil shield, and the forming surface 9B at a fitting position B with a core and an other-side oil shield 4 is set to be formed. When a round-rod-formed rotary shaft 1 is set between the metallic molds 7, 7 and is press-formed by pressure with the metallic molds 7, 7 from upper and lower sections, then the level of a salient strip section formed on the forming surface 9A is formed to be low, and the level of a salient strip section 5 formed on the forming surface 9B is formed to be high, and both salient strip sections are formed at the same time in cross-sectional-wedge shapes with sharp tips. Difference between the outer diameters of the salient strip sections is set to be difference between the retaining forces, and the suitable retaining forces accommodated to fitting component parts can be obtained.
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