Method of manufacturing rotor of electric motor and electric motor

Abstract

A method of manufacturing a rotor of an electric motor, the rotor including a laminated core of multilayer structure formed from electromagnetic thin plates laminated in an axial direction of a rotational shaft, and a pair of end plates disposed on opposite sides in the axial direction of the laminated core, and the rotor being rotatably disposed in an inside of a stator, the method including: fitting the rotational shaft into an insertion hole formed in a center region of the end plates having elasticity in a direction of plate thickness; positioning the end plates at specified position on the rotational shaft; and abutting either one of the end plates in elastically deformed state to at least one end of the laminated core.

Description

technical field [0001] The present invention relates to a method of manufacturing a motor rotor which is rotatably arranged inside a stator and which is suitable for use in machine tools, automatic machines, press machines, injection molding machines, etc., and an electric motor. Background technique [0002] Generally, for an inner-rotor-type electric motor in which a motor rotor is arranged inside a stator, the motor rotor includes: a rotating shaft; A pair of end plates arranged on both sides in the axial direction of the laminated core are provided with the rotation shaft inserted into an insertion hole formed in the central portion to communicate with each other. [0003] The motor disclosed in Japanese Patent Application Laid-Open No. 9-233750 includes an inner rotor in which permanent magnets longer than the axial dimension of the laminated core are embedded, and one of the two ends of the laminated core is arranged. At least one of the pair of end plates is pressure...

AI Technical Summary

Problems solved by technology

[0005] However, in conventional motors, since the pair of end plates are fixed by a fastening mechanism such as screws or rivets, there are problems that the number of parts increases and the assembly of the pair of end plates is troublesome, resulting in high manufacturing costs.

[0006] In addition, in the conventional motor, although the end plate and the end portion of the permanent magnet are in contact, there may be a gap between the end plate and the end surface (end surface of the thin plate) of the laminated core without contact. If a gap occurs, when the inner rotor is inserted into the stator during assembly of the motor, the outer peripheral surface of the rotor and the inner peripheral surface of the stator may come into sliding contact and each laminated thin plate of the multilayer structure may be peeled off.

In particular, in large motors for high output that are suitable for machine tools, etc., there is a problem that the mechanical strength decreases due to peeling of each laminated sheet

[0007] Apparently, the problem of creating a gap between the end plate 55 and the laminated core 50 is that, as shown in FIG. The warping of the lamination core 50, or as shown in FIG.

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