Scroll Compressor Stator Mounting to Suppress Elliptical Vibration
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Solution Overview
Problem
Vibrations in the housing and stator of a scroll compressor can diverge, leading to increased noise due to superimposed vibration modes, particularly in an elliptical mode.
Innovation Solution
The stator is fixed to the inner peripheral surface of the housing at multiple fixing points that are positioned differently from the intersections of the first and second straight lines defining the elliptical mode, and these fixing points are arranged in a square or pentagonal shape to avoid overlapping resonant modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the stator is fixed at the intersections of the first and second straight lines (where the housing has high rigidity), then the housing rigidity is maintained, but vibrations diverge and noise increases due to superimposed elliptical mode vibrations
Solution Approach 1:
The patent applies asymmetry by deliberately positioning the stator fixing points away from the symmetric intersection points of the first and second straight lines. The fixing points are arranged asymmetrically relative to the elliptical mode vibration pattern, which prevents the stator vibrations from synchronizing with and amplifying the housing vibrations. This asymmetric positioning breaks the resonance condition that would otherwise occur at the high-rigidity intersection points.
Solution Approach 2:
The patent applies local quality by creating different fixing conditions at different locations on the housing. Instead of uniformly fixing the stator at all high-rigidity points (intersections of straight lines), the patent selectively positions fixing points at specific locations that are offset from these intersections. This localized differentiation in fixing position allows the system to maintain overall housing rigidity while avoiding specific locations that would amplify vibrations.
2Strength
If attachment legs are provided at positions facing each other in radial direction, then the housing has higher rigidity, but elliptical mode vibrations occur and can diverge with stator vibrations
Solution Approach 1:
The patent applies asymmetry by positioning the stator fixing points asymmetrically with respect to the attachment legs and the elliptical mode vibration pattern. The fixing points are deliberately placed at locations that are not aligned with the major and minor axes defined by the attachment legs, which prevents the stator from participating in and amplifying the elliptical mode vibrations while the attachment legs maintain housing rigidity.
3Reliability
If the stator is fixed at multiple fixing points, then the stator is securely attached to the housing, but vibrations may diverge if fixing points are at wrong positions
Solution Approach 1:
The patent applies local quality by creating different fixing conditions at different locations on the housing. Instead of uniformly fixing the stator at all high-rigidity points (intersections of straight lines), the patent selectively positions fixing points at specific locations that are offset from these intersections. This localized differentiation in fixing position allows the system to maintain overall housing rigidity while avoiding specific locations that would amplify vibrations.
Solution Approach 2:
The patent applies feedback by considering the vibration characteristics of the housing and stator when determining the fixing point positions. The design incorporates knowledge of the elliptical mode vibration pattern and uses this information to position fixing points that avoid resonance. This feedback-based positioning ensures that the stator is securely attached while preventing vibration divergence and noise generation.
Data Source
AI summary
This compressor comprises a compressor body, an electric motor that has a rotating shaft extending along an axis and drives the compressor body via the rotating shaft, and a housing that houses the compressor body and the electric motor. The electric motor has a rotor capable of rotating about the axis and an annular stator centered about the axis. The housing has a housing body and a pair of highly rigid parts that are provided on the outer side of the housing body in positions opposite in the radial direction and that have higher rigidity than other portions. The stator is fixed to the inner peripheral surface of the housing at a plurality of fixing points provided at positions different from points where the housing intersects with a first straight line connecting the pair of highly rigid parts and a second straight line orthogonal to the first straight line.