JPS54150700A - Manufacture of magnet - Google Patents

Abstract

PURPOSE:To raise the magnetic flux density on the surface of a magnet, by magnetically orienting ferrite particles mixed with a medium such as rubber or synthetic resin in the direction of rolling and by magnetizing a stratified piece of the mixture to provide the piece with projections and recesses which are located alternately and by magnetizing the piece. CONSTITUTION:The mixture of the ferrite particles 1 with the binding medium 2 such as rubber or synthetic resin is rolled between rotating rolls 3 to a sheet 4 which has a thickness of 0.5 to 3.0 mm and wherein the magnetically anisotropic ferrite particles are magnetically oriented in the direction of the rolling. Such sheets are stratified with one another to a required thickness. The stratified piece is pressed so that the piece is provided with the projections 14 and recesses 10 whose cross section is semicircular. The central parts of the projections and recesses are magnetized to N-poles and S-poles alternately. Because the ferrite particles 1 oriented in the magnetic flux extending out of the S-poles always show an angel near to 90 deg., the magnetic flux density is raised by 60% more than that of conventional magnets.