Welded Stator Core Layout to Prevent Bolt-Induced Deformation

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Solution Overview

Problem

The existing methods for fixing a stator core using bolts can cause deformation due to torsional forces, especially when the stator core is composed of stacked plate members, which affects the structural integrity and magnetic characteristics of rotary electric machines.

Innovation Solution

A stator core design featuring a core back in an annular shape with radially inward teeth, a hole on its outer surface, and a weld on the radially outer surface, including a first weld on a virtual line connecting the hole and the central axis, which enhances structural strength and minimizes deformation while maintaining magnetic flux integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a stator core is fixed with a bolt, then the stator core can be securely fixed, but the torsional force from tightening the bolt deforms the stator core and plate members

Engineering Contradiction:

Improvefixing securityVSAvoidstator core deformation

Core Design Contradiction:

Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent replaces the mechanical bolt tightening system with a welding system. Instead of using a bolt that requires torsional tightening force, the stator core is fixed using welds that join the stator core to the housing without applying deforming torsional forces to the plate members.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a welding intermediary process that joins the stator core to the housing through fusion rather than mechanical fastening. The weld acts as an intermediary connection method that eliminates the need for bolt holes and torsional tightening, thereby preventing deformation of the stacked plate members.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If the stator core is composed of stacked plate members, then the stator core can be manufactured, but the plate members are prone to deformation under bolt tightening forces

Engineering Contradiction:

Improvestator core constructionVSAvoidplate member structural integrity

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The patent replaces the mechanical bolt connection system with welding, eliminating the torsional forces that cause deformation of stacked plate members while maintaining the manufacturability of the stator core structure.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fixing method parameter from mechanical fastening to thermal welding, which fundamentally alters how the stator core is secured without introducing deforming forces to the plate members.

Inventive Principle:

Principle #35Parameter changes

3Stability of the object's composition

If a hole is provided in the stator core for bolt insertion, then the stator core can be fixed to the housing, but the hole and bolt create stress concentration points that may deform the stator core

Engineering Contradiction:

Improvestator core fixationVSAvoidstator core structural integrity

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The patent extracts and removes the hole from the stator core by eliminating the bolt fixation method entirely. Instead of having a hole that creates stress concentration, the stator core is welded to the housing, maintaining the integrity of the plate member stack.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent substitutes welding for mechanical bolt fixation, eliminating the need for holes in the stator core and thereby removing the stress concentration points that would compromise structural integrity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The proposed design effectively suppresses deformation of the stator core and maintains the magnetic characteristics of the rotary electric machine, preventing output deterioration while securely fixing the plate members.

Implementation Method 1

a weld provided on a radially outer surface of the stator core. The weld includes a first weld provided on the radially outer surface of the stator core on a virtual line connecting the hole and the central axis as viewed in the axial direction

Methodology Applied

Scientific EffectWelding: Welding

Data Source

PatentUS12081069B2Stator, rotary electric machine, drive device, and mobile unit

Publication Date: 2024.09.03 NIDEC CORP(JP)

AI summary

A stator according to an aspect of the present invention includes a stator core having a core back in an annular shape surrounding a central axis of the stator, and a plurality of teeth extending radially inward from the core back. The stator core has a hole provided in a radially outer portion of the stator core, the hole extending in an axial direction, and a weld provided on a radially outer surface of the stator core. The weld includes a first weld provided on the radially outer surface of the stator core on a virtual line connecting the hole and the central axis as viewed in the axial direction.