Stepping Motor Stator Press Fitting with Segmented Chamfer

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing stepping motors face issues with foreign object debris generation during stator press fitting, which increases manufacturing costs and complexity due to the need for additional steps to remove these objects from the torque transmission mechanism.

Innovation Solution

The stepping motor design incorporates a recess with a chamfered portion and a press fitting portion, featuring multiple slant surfaces with decreasing angles from the inlet opening end to the bottom, reducing the likelihood of debris generation by minimizing corner contact and scraping during the press fitting process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a single chamfered inlet opening end is used to facilitate press fitting, then the positioning of the stator is eased, but foreign object debris is generated from the casing

Engineering Contradiction:

Improvepress fitting operationVSAvoidforeign object debris

Core Design Contradiction:

Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The chamfered portion is divided into multiple slant surfaces (first slant surface and second slant surface) with different angles, segmenting the single chamfer into multiple functional zones that collectively reduce debris generation while facilitating press fitting

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the chamfered portion have different slant surface angles tailored to specific functions: the first slant surface with a larger angle facilitates initial positioning and entry, while the second slant surface with a smaller angle reduces scraping and debris generation during final seating

Inventive Principle:

Principle #3Local quality

2Stability of the object's composition

If the stator is press fitted into the recess, then the stator is securely held in the casing, but the casing is scraped by the stator corner generating debris

Engineering Contradiction:

Improvestator positioningVSAvoidscraped debris

Core Design Contradiction:

Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The chamfered portion with multiple slant surfaces is provided in advance to prevent the scraping action before it occurs, by guiding the stator corner through a controlled path that minimizes direct scraping contact with the casing during press fitting

Inventive Principle:

Principle #9Preliminary anti-action

3Reliability

If foreign objects are removed after press fitting, then the motor reliability is improved, but the number of manufacturing steps increases

Engineering Contradiction:

Improvemotor operationVSAvoidmanufacturing steps

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The recess geometry with multiple slant surfaces is designed in advance to prevent foreign object generation during press fitting, eliminating the need for subsequent foreign object removal steps and reducing manufacturing complexity while maintaining reliability

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS7276825B2Stepping motor

Publication Date: 2007.10.02 DENSO CORP

AI summary

A stator is press fitted into a recess of a casing. The recess has a chamfered portion. The chamfered portion is arranged between an inlet opening end of the recess and a bottom of the recess in such a manner that a width of the recess is progressively increased along the chamfered portion from a bottom side toward an inlet opening end side of the recess. The chamfered portion has a plurality of slant surfaces, which are arranged one after another in the press fitting direction of the stator. Angles of the plurality of slant surfaces with respect to the press fitting direction of the stator decrease from the inlet opening end side of the recess toward the bottom side of the recess.