Mold for and method of producing polar anisotropic ring-shaped bonded magnet molded articles

A mold for a polar anisotropic ring-shaped bonded magnet molded article, comprising a cavity whose outer periphery is defined by the following equations in rectangular coordinates (x,y), with an origin at a center of the mold cavity:

• x={(Dm+β×Tc/2)+(β×Tc/2)sin(Pθ)}×cos θ, and
• y={(Dm+β×Tc/2)+(β×Tc/2)sin(Pθ)}×sin θ
• wherein α1 represents a shrinkage ratio of a molded specimen in a direction vertical to a magnetic field;
• α2 represents a shrinkage ratio of the molded specimen in a direction parallel to the magnetic field;
• T represents a wall thickness of a desired polar anisotropic ring-shaped bonded magnet molded article;
• P represents a number of magnetic poles of the molded article;
• D represents an outer radius of the molded article;
• Tc represents a shrinkage length of the molded article as defined by T×(α1/100−α2/100);
• Dm represents a radius of a magnetic pole portion of the mold cavity as defined by D/(1−α2/100);
• β represents a correction factor and 0.7≤β≤1.0;
• and 0≤θ≤2π.