| 摘要 |
A method of forming flanged commutator segmental rings in a single power stroke by cold-extrusion which assures full formation of the inner ribs which become commutator segments, so that the segments will anchor well and resist centrifugal force at high rotational speed. The extrusion apparatus has an inner rib-forming die (18) and an outer ring-shaped flange-forming die (16). In the first stage of the power stroke, a ring-shaped blank (1) is formed into a flange precursor and a shaft portion (24) with inner ribs. In the second stage of the power stroke, the ring-shaped die (16) forms the flange (4) while the rib-forming die (18) forms a longer shaft (3) with a full complement of inner ribs (5) and a counter-punch (13) maintains pressure. |
