Motor Housing with Variable Inner Diameter for Controller Integration

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Solution Overview

Problem

The integration of a motor case and a controller accommodating member increases the number of components, making it difficult to reduce the size of the motor, and poses challenges in inserting components like the stator and bearing holder, which can damage the motor case during assembly.

Innovation Solution

A motor design with a housing that includes a controller accommodating region with a larger inner diameter than the bearing holder attachment area, allowing for the accommodation of a controller connected to the stator, and a bearing holder with a recessed portion and pressing portion to securely hold the upper bearing, reducing the risk of damage during assembly and enabling miniaturization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the motor case and controller accommodating member are integrated into a common motor case, then the number of components is reduced and size is minimized, but the inner peripheral surface of the motor case is likely to be damaged during assembly

Engineering Contradiction:

Improvenumber of componentsVSAvoiddamage to motor case

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The housing inner peripheral surface is provided with a protective layer that has different properties from the base housing material. This protective layer specifically protects the inner peripheral surface where components are inserted, while the rest of the housing maintains its original structure and properties.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The protective layer is applied in advance to the housing inner peripheral surface before assembly operations. This pre-applied protective layer prevents damage during the insertion of the stator and bearing holder, addressing the potential harm before it occurs.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Adaptability or versatility

If the motor case is lengthened to accommodate the controller, then the controller can be housed in the same case, but it becomes difficult to insert the stator and bearing holder

Engineering Contradiction:

Improvecontroller accommodationVSAvoidcomponent insertion difficulty

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The housing is designed with different inner diameter regions: a first inner diameter in the controller accommodating region and a second inner diameter in the bearing holder attachment region. This local variation allows the controller to be accommodated while maintaining sufficient clearance for inserting the stator and bearing holder.

Inventive Principle:

Principle #3Local quality

3Object-affected harmful factors

If the inner diameter of the housing in the controller accommodating region is made larger, then components can be inserted without damage, but the motor size increases

Engineering Contradiction:

Improveprevention of motor case damageVSAvoidmotor size

Core Design Contradiction:

Object-affected harmful factorsVSVolume of moving object

Solution Approach 1:

The housing inner diameter varies locally: it is larger in the controller accommodating region to prevent damage during insertion, while maintaining a smaller diameter in other regions to minimize overall motor size.

Inventive Principle:

Principle #3Local quality

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 design allows for the reduction of the motor's size by minimizing the number of components and preventing damage to the motor case during assembly, while maintaining the necessary inner diameters for proper component fitment and stability.

Implementation Method 1

an urging member that performs urging in the upward and downward direction is positioned between an upper surface of the outer ring and the upper bearing receiving portion

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS11088588B2Motor with an upper bearing including a washer, a lower bearing, and bearing holding portions

Publication Date: 2021.08.10 NIDEC CORP(JP)

AI summary

A motor includes a rotor that includes a shaft centered on a central axis extending in an upward and downward direction; a stator that is disposed to face the rotor in a radial direction; a bearing that supports the shaft; a bearing holder that holds the bearing; and a housing that accommodates the rotor, the stator, and the bearing holder, and opens to an upper side. The housing includes a controller accommodating region that accommodates at least a portion of a controller electrically connected to the stator on an upper side from the bearing holder. An inner diameter of the housing in the controller accommodating region is larger than an inner diameter of the housing at a position to which the bearing holder is attached. The bearing holder is held on an inner peripheral surface of the housing by interference fitting.