| 摘要 |
A method of making a cylindrical ferromagnetic body and cover assembly for a rotor of a dc motor is provided. In a first embodiment, a blend of a powdered ferromagnetic material and a heat-curable binder is compressedly molded into a cylindrical form in a generally cylindrical non-magnetic cover material having an annular flange around the top thereof, while heat is applied to the material from a heated stationary mold through the cover material, so that the cylindrically-molded ferromagnetic body firmly adheres to the cover material in the molding process. After the ferromagnetic body is cured, an non-magnetic annular protector is placed on the top of the cylindrically-molded body and the annular flange is radially inwardly bent over onto the protector. In a second embodiment, a heated block of a powdered ferromagnetic material is deposited in a cup-shaped non-magnetic cover material. The block is subsequently pressedly molded into a cup-shaped form in the cup-shaped cover material so that the molded material firmly adheres to the cover material. After the molded material is cooled, a top section and a bottom section of the cup-shaped body, together with the corresponding top section and the bottom section of the cover material, are cut off so as to obtain a cylindrical ferromagnetic body and cover assembly.
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