Rare earth cobalt permanent magnet, method and device for manufacturing same

Abstract

Provided are a rare earth cobalt permanent magnet having excellent magnetic characteristics, a method and device for manufacturing such a rare earth cobalt permanent magnet. The rare earth cobalt permanent magnet is composed of 23 to 27 mass% of R, 1.0 to 5.0 mass% of Cu, 18 to 25 mass% of Fe, 1.5 to 3.0 mass% of Zr, and Co as the remainder and unavoidable impurities. R represents a rare earth element including at least Sm; the rare earth cobalt permanent magnet includes a plurality of crystal grains and a grain boundary portion; and in the grain boundary portion, the concentration of Cu is at least twice the concentration of Zr.

Description

technical field [0001] The present disclosure relates to a rare earth cobalt permanent magnet applicable to a variable field motor, a method and a device for manufacturing the rare earth cobalt permanent magnet. Background technique [0002] Variable field motors have gained attention due to their ability to reduce the energy consumed by the motor. In a variable field motor, its magnetic flux varies according to the number of revolutions per unit time (eg, RPM). Generally, for a variable field motor, it is required to generate high magnetic flux when high torque is required at low speed, and reduce the magnetic flux when the motor rotates at high speed, so that the motor has high energy efficiency in a wide range from low speed to high speed. [0003] Examples of methods of changing magnetic flux in a variable field motor include a variable magnetic force method, a field coil method, and a winding switching method. For example, Japanese Patent No. 4965924 discloses a metho...

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Problems solved by technology

However, in the technology disclosed in International Patent Publication No. WO2009/145229, the residual magnetization value is 8

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