Rotary Electric Machine Floor Strain Relief via Indented Recess
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Solution Overview
Problem
Conventional rotary electric machines face issues with ensuring the horizontalness of the stator housing floor portion due to strain from press-fitting, leading to vibration and noise during operation, and increasing the floor thickness to mitigate this worsens the problem by altering the center of gravity and resonance point.
Innovation Solution
A rotary electric machine design featuring a first stress relieving indented portion around the cylindrical portion's inner circumference, creating a gap between the stator core and the cylindrical portion to release strain, ensuring horizontalness without increasing the floor thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the thickness of the floor portion is reduced, then the weight of the motor housing is reduced, but horizontalness of the floor portion cannot be ensured due to strain from press-fitting
Solution Approach 1:
The patent divides the floor portion into multiple segments by forming recesses (first recess and second recess) that extend in the thickness direction. This segmentation allows strain from press-fitting to be localized within the recesses rather than propagating across the entire floor portion, thereby maintaining horizontalness even with reduced thickness.
Solution Approach 2:
The patent applies local quality by creating regions of different structural properties within the floor portion. The recesses create localized areas that can accommodate strain, while the remaining portions of the floor maintain their structural integrity and horizontalness. This allows the floor to have both reduced overall thickness and maintained precision in critical areas.
2Manufacturing precision
If the thickness of the floor portion is increased, then horizontalness of the floor portion is ensured, but the weight of the motor housing increases
Solution Approach 1:
Instead of uniformly increasing the thickness of the entire floor portion, the patent segments the floor structure by adding recesses. This allows the floor to maintain adequate thickness only in areas where structural support is needed, while reducing thickness in areas where strain accumulation would cause horizontalness issues.
Solution Approach 2:
The patent changes the structural parameters of the floor portion by introducing recesses with specific dimensions and positions. These parameter changes create a optimized structure that achieves the required horizontalness with minimal material, thereby reducing weight while maintaining precision.
3Manufacturing precision
If the thickness of the floor portion is increased, then horizontalness is ensured, but the center of gravity moves away from the external surface causing resonance and vibration
Solution Approach 1:
The segmentation of the floor portion through recesses allows the structure to maintain horizontalness without increasing overall thickness. This keeps the center of gravity close to the external surface, avoiding the resonance and vibration issues that would result from moving the center of gravity farther away.
Solution Approach 2:
By changing the structural parameters through the introduction of recesses, the patent achieves the required horizontalness with minimal thickness increase. This parameter optimization ensures that the center of gravity remains in an optimal position, preventing resonance and vibration during motor operation.
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 solution effectively reduces strain on the floor portion, maintaining horizontalness and preventing vibration and noise, while keeping the floor thickness unchanged, thus optimizing the motor's mounting and operational stability.
Implementation Method 1
a first stress relieving indented portion is formed around an entire circumference at a first end of an inner circumferential surface of the cylindrical portion such that a gap is formed between a first end portion of an outer circumferential surface of the stator core and the cylindrical portion. Thus, strain that arises in the cylindrical portion when the stator is fitted inside and fixed to a case by press-fitting or shrinkage fitting is released at the first stress relieving indented portion
Data Source
AI summary
A rotary electric machine includes: a floored cylindrical case in which an opening at a first end of a cylindrical portion is closed by a floor portion; a stator that includes: an annular stator core that is held inside the case by being fitted together with and fixed to the cylindrical portion; and coils that are mounted to the stator core; a frame that closes an opening at a second end of the cylindrical portion; and a rotor that is fixed to a rotating shaft, and that is disposed on an inner circumferential side of the stator, wherein: a first stress relieving indented portion is formed around an entire circumference at a first end of an inner circumferential surface of the cylindrical portion such that a gap is formed between a first end portion of an outer circumferential surface of the stator core and the cylindrical portion.