US Patent No. 9,356,480

ELECTRIC MOTOR HAVING ROTOR STRUCTURE FOR AVOIDING DEFECT DUE TO STRAIN GENERATED BY TEMPERATURE CHANGE, AND PRODUCTION METHOD THEREOF


Patent No. 9,356,480
Issue Date May 31, 2016
Title Electric Motor Having Rotor Structure For Avoiding Defect Due To Strain Generated By Temperature Change, And Production Method Thereof
Inventorship Akira Yamaguchi, Yamanashi (JP)
Tsuyoshi Furuya, Yamanashi (JP)
Assignee FANUC CORPORATION, Yamanashi (JP)

Claim of US Patent No. 9,356,480

1. A production method of an electric motor comprising a stator and a rotor configured to be rotated relative to the stator,
wherein the method comprises the steps of:
constituting a rotor core by stacking magnetic steel plates;
aligning a plurality of permanent magnets in a direction of a rotation axis of the rotor and fixing the permanent magnets
to the magnetic steel plate by means of adhesives;

positioning an intervening member, which melts at a temperature higher than a curing temperature of the adhesives, between
the permanent magnets which are adjacent to each other in the direction of the rotation axis; and

heating the rotor after the adhesives are cured so that the intervening member melts and flows from between neighboring permanent
magnets,

wherein a thickness of the intervening member in the direction of the rotation axis is determined so that neighboring permanent
magnets, which are bonded to the rotor core within a manufacturing temperature range of the rotor, do not contact each other
at a lower limit of an operating temperature of the electric motor.