| 摘要 |
PURPOSE:To shorten a manufacturing process and to reduce manufacturing cost, by using a ring shaped member, which comprises a magnetic material having teeth and gaps alternately arranged in the circumferential direction, as an insert and preparing a cylindrical member comprising engineerting plastic by injection molding. CONSTITUTION:A ring shaped member 44 comprises a magnetic material and has an annular part 46 and teeth 48 protruded to the axial direction from the annular part 46 and arranged at equal angular intervals in the peripheral direction. A cylindricalmember 62 made of engineering plastic having said members 44 embedded therein as inserts is prepared by injection molding. The end part surface of a rotor 38 provided with teeth 48 has arrangement such that teeth 48 made of a magnetic material and parts of the members 62 made of engineering plastic are alternately repeated in the peripheral direction. By this method, processes such as the cutting of the inner and outer diameters of a base pipe, phosphate treatment or cutting or press molding for forming a tooth shape become unnecessary. Because heat caulking for melting a synthetic resin by heat can be utilized in the assembling of a rotor, caulking becomes easy and bonding strengh also increases.
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