| 摘要 |
PURPOSE:To inexpensively manufacture a cylindrical permanent magnet having high magnetic performance by attaching a magnetic material to the ends of outer and inner dies made of nonmagnetic material, and lengthening the end of the inner die from the front face of the outer die. CONSTITUTION:A material injection outer die 1 is made of a nonmagnetic material, and a molding outer die 2 is also made of the nonmagnetic material, but a ringlike magnetic material 2a for inducing a magnetic flux is attached to its end. An inner die 3 is also made of a nonmagnetic material, and a magnetic material 3a is attached to its end. An electromagnetic coil 4 is mounted outside a die. When a current flows to the coil 4, the generated magnetic flux flows as designated by arrows. In this case, the end 3a of the die 3 is lengthened in the length of 1/4 or longer of the diameter of the end 3a from the front face of the magnetic material ring 2a attached to the end of the die 2. Since the coil and the mold are not integrated, its structure is simple, and time and cost required to manufacture the mold may be less.
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