Split-Core Stator Yoke Engagement to Reduce Assembly Deformation

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Solution Overview

Problem

Existing methods for attaching an auxiliary yoke to a main yoke in DC motors often result in deformation of the main yoke, require high precision for diameter accuracy, and are prone to issues like peeling coatings, machine oil accumulation, and increased manufacturing costs.

Innovation Solution

A stator design featuring a cylindrical main yoke with a band-shaped auxiliary yoke that engages via protrusions and recesses along the circumferential direction, allowing for secure attachment without large physical forces, thus minimizing deformation and precision requirements, and avoiding issues like peeling and oil accumulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional methods are used to attach the auxiliary yoke to the main yoke, then the auxiliary yoke can be securely attached, but the main yoke deforms and requires high precision for diameter accuracy

Engineering Contradiction:

Improveattachment securityVSAvoiddiameter accuracy

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The attachment structure is divided into multiple engagement points around the circumferential direction. Multiple protrusions and corresponding recesses are distributed along the circumferential direction, distributing the attachment forces across multiple locations rather than concentrating them at a single point, thereby reducing deformation and relaxing precision requirements

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The attachment mechanism transitions from radial attachment to circumferential attachment. Instead of attaching the auxiliary yoke radially to the main yoke, the protrusions and recesses engage along the circumferential direction, changing the dimension of attachment forces and reducing radial deformation of the main yoke

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If traditional attachment methods are used, then the auxiliary yoke can be secured to the main yoke, but large physical forces cause deformation and coating peeling

Engineering Contradiction:

Improveattachment securityVSAvoidphysical impact and coating peeling

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The attachment structure incorporates flexibility through the circumferential engagement design. The auxiliary yoke can dynamically adjust its position along the circumferential direction to accommodate minor dimensional variations, reducing the need for large attachment forces and preventing coating peeling

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The protrusions and recesses act as intermediary elements between the auxiliary yoke and main yoke. These engagement features distribute and soften the attachment forces, preventing direct transmission of large physical forces that would cause deformation and coating damage

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If traditional attachment methods are used, then the auxiliary yoke can be attached to the main yoke, but manufacturing costs increase due to high precision requirements

Engineering Contradiction:

Improveattachment securityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The attachment is segmented into multiple circumferential engagement points, allowing standard manufacturing tolerances to be distributed across multiple locations. This segmentation reduces the precision requirements for each individual engagement point, lowering manufacturing costs while maintaining overall attachment reliability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The attachment mechanism changes the critical parameter from radial dimensional accuracy to circumferential engagement. By shifting the precision requirement to the circumferential direction where standard tolerances are more easily achieved, the manufacturing cost is reduced while maintaining secure attachment

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11990792B2Stator with split core and yoke with protrusions and recesses engaging together and surrounding the split core

Publication Date: 2024.05.21 DENSO CORP

AI summary

A stator includes a main yoke having a cylindrical shape with a bottom, an auxiliary yoke having a band shape arranged on an outer or inner circumferential wall surface of this main yoke, and a field magnet arranged inside the main yoke. The auxiliary yoke is arranged along a circumferential direction on the outer or inner circumferential wall surface of the main yoke. One end of the auxiliary yoke has at least one protrusion, and another end of the auxiliary yoke has at least one recess facing and engaging in a circumferential direction with the protrusion either on the inner or outer circumferential wall surface of the main yoke.