METHOD OF MANUFACTURING FOUR-POLE CYLINDRICAL PERMANENT MAGNETS Russian patent published in 1994 - IPC

FIELD: powder metallurgy. SUBSTANCE: method of making four-pole cylindrical permanent magnets comprises steps of pressing blanks of powder of magnetically hard ferrites in a magnetic field, providing sizes of outer and inner surfaces of the blank, calculated according to formulae , , where x_i, y_i - coordinates of a generatrix of the outer surface of the blank; x_j, y_j - coordinates of an inner opening of the blank; R, r - radius values of the outer surface and of the inner opening of the sintered blank; - shrinkage factors of the textured blank material in points i, j of the outer and inner surfaces of the blank in direction of a vector, passed from a center to a given point; α - angle between the X-axis and the vector, passing from the center of coordinate to the given point i, j of surfaces of the blank; selecting the blank center, being the coordinate center, and selecting directions of X-and Y-axis, corresponding to mutually normal symmetry axis of the blank, passing through centers of pole portions of the blank; placing a source of the magnetic field upon pressing process at a point of coincidence of centers of poles of the source with the symmetry axis of the blank along the coordinate axis; sintering the blanks and sizing them. EFFECT: enhanced quality of magnets. 1 cl, 2 tbl