Stator Cover Stepped Portion Axial Positioning

Solution Overview

Problem

The existing techniques for enhancing water-proofness of stators by using a cover member with a tubular shape face challenges in maintaining accurate axial positioning due to the thickness of the tubular portion, which affects rotational characteristics and can lead to deformation, compromising the accuracy of the axial position of the cover member with respect to the stator.

Innovation Solution

The proposed solution involves a stator assembly with a cover member that includes a tubular portion, a lid portion, and a cover stepped portion, where the tubular portion extends axially and radially to cover the stator, and the cover stepped portion contacts the stator's upper end, allowing for precise axial positioning by fitting into the stator's teeth portions, thereby ensuring accurate alignment and reducing deformation risks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the tubular portion is made thicker to prevent deformation, then the strength and stability of the cover member is improved, but the magnetic gap between the rotor and stator increases, deteriorating rotational characteristics

Engineering Contradiction:

Improvestrength of tubular portionVSAvoidrotational characteristics

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The cover member is divided into functionally distinct portions: a thin-walled tubular portion for water protection and a thick-walled cover stepped portion for structural support and positioning. This segmentation allows each portion to be optimized for its specific function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different wall thicknesses are applied to different portions of the cover member. The tubular portion has a first wall thickness optimized for water-proofness, while the cover stepped portion has a second wall thickness greater than the first, providing localized structural reinforcement where needed for positioning and support.

Inventive Principle:

Principle #3Local quality

2Reliability

If the tubular portion is made thinner to reduce magnetic gap, then the rotational characteristics are improved, but the tubular portion becomes prone to deformation and axial positioning accuracy deteriorates

Engineering Contradiction:

Improverotational characteristicsVSAvoidaxial position accuracy

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The cover member is divided into functionally distinct portions: a thin-walled tubular portion for water protection and a thick-walled cover stepped portion for structural support and positioning. This segmentation allows each portion to be optimized for its specific function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The cover stepped portion acts as an intermediary structure that provides the necessary structural support and axial positioning function, allowing the tubular portion to be made thin for optimal rotational characteristics while maintaining positioning accuracy through the stepped portion's contact with the stator.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Strength

If a cover member with uniform thickness is used to ensure structural integrity, then the strength is improved, but the axial position determination accuracy with respect to the stator deteriorates

Engineering Contradiction:

Improvestructural integrityVSAvoidaxial position determination accuracy

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

Different wall thicknesses are applied to different portions of the cover member. The tubular portion has a first wall thickness optimized for water-proofness, while the cover stepped portion has a second wall thickness greater than the first, providing localized structural reinforcement where needed for positioning and support.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The cover member is divided into functionally distinct portions: a thin-walled tubular portion for water protection and a thick-walled cover stepped portion for structural support and positioning. This segmentation allows each portion to be optimized for its specific function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS10965179B2Stator unit, motor, and blower apparatus

Publication Date: 2021.03.30 NIDEC CORP(JP)

AI summary

A stator assembly includes a stator that drives a rotor rotatable about a central axis extending in a vertical direction, a cover that accommodates the stator, a filling portion that fills a space between the cover and the stator. The cover includes a tubular portion that extends in an axial direction and covers a radially side portion of the stator opposing the rotor in a radial direction, a lid portion that covers an axially upper end portion of the stator, and a cover stepped portion that is provided on a first radial side with respect to the tubular portion. The cover stepped portion comes in contact with the axially upper end portion of the stator and is positioned on an axially lower side with respect to an axially upper end portion of the tubular portion.