Preform, preforming method, and method of producing compression-bonded magnet

Abstract

A preform maintains shape retention properties and handling ability while suppressing deterioration in bonded magnet magnetic characteristics. A preform having an outer shell portion formed by binding a part of a magnet raw material of a mixture or kneaded product of magnet particles and a thermosetting resin that is powdery or granular, and an inner encapsulated portion formed of a remainder of the magnet raw material present inside the outer shell portion which maybe a portion in which the thermosetting resin has bound while still uncured. The inner encapsulated portion includes a powdery or granular magnet raw material. The preform is obtained by a preforming step of subjecting the magnet raw material to warm pressurization compacting, and maybe carried-out by setting a preforming temperature (Tp), which is the temperature of a preforming mold inner wall surface to be filled with magnet raw material, to ts≤Tp≤ts+20° C. (ts: thermosetting resin softening point).

Dependencies are inferred from the claim text.