Stator Core Cutout Design for Electrical Motor Dimensional Accuracy
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Solution Overview
Problem
Conventional methods for forming a straight core type stator in electrical motors face challenges in achieving high dimensional accuracy, leading to reduced magnetic circuit performance, increased noise, and lower energy conversion efficiency due to deformation stresses and poor blanking and laminating accuracy.
Innovation Solution
A stator core design with V-shaped cutouts that increase in width from the outside diameter to the inside diameter, with a sum of opening angles greater than 360 degrees, allowing for a minute clearance between segments when bent into an annular shape, reducing deformation stresses and improving alignment accuracy through an insert molding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the opening angle of the cutout is set to (360/α) to make clearance zero when bending straight core into annular shape, then the dimensional accuracy is improved, but deformation stresses concentrate in the cutout part causing magnetic circuit performance degradation
Solution Approach 1:
The invention changes the opening angle parameter of the cutout from the conventional (360/α) to a value larger than (360/α). This parameter modification creates a clearance between the cutout surfaces when bent, preventing stress concentration while maintaining dimensional accuracy through the elastic restoring force of the deformed cutout portion.
2Manufacturing precision
If two side wall surfaces of the cutout are caused to abut on each other to increase dimensional accuracy, then the degree of complete round is improved, but blanking accuracy and laminating accuracy must be set high requiring advanced production control
Solution Approach 1:
The invention beforehand cushions the dimensional accuracy requirement by designing the cutout opening angle to be larger than (360/α), which creates a clearance that compensates for variations in blanking and laminating accuracy. This eliminates the need for advanced production control while maintaining high dimensional accuracy.
3Manufacturing precision
If the straight core is bent into annular shape with zero clearance cutout, then the dimensional accuracy is maximized, but strain is added to the end faces causing influence on magnetic circuit
Solution Approach 1:
The invention converts the potential harm of strain concentration into a benefit by designing the cutout with an opening angle larger than (360/α). The clearance created prevents strain accumulation at the end faces, while the elastic deformation of the cutout portion provides a self-aligning mechanism that enhances dimensional accuracy.
Data Source
Figure 1
Figure 2A~2B
Figure 3~4C
AI summary
There is provided an electrical motor in which the dimensional accuracy of a stator is increased more easily, and the influence exerted on a magnetic circuit is kept as little as possible. In an electrical motor in which the stator 3 formed with n number (n is a positive integer) of teeth 33 in a row in a straight line form is bent into an annular shape and the end parts thereof are connected to each other, the sum of opening angles θ of a cutout 35 formed between segments of the stator 3 is made larger than 360 degrees, and a minute clearance is formed between the opposed surfaces of the cutout 35 when the stator is bent into an annular shape.