Hermetic Rotary Compressor Stability via High Aspect Ratio and Asymmetric Legs
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Hermetically sealed rotary compressors face challenges in increasing refrigeration capacity without enlarging their installation area and ensuring stability against loads or moments, as larger compressors require more space and are prone to toppling.
Innovation Solution
The compressor design features four support legs arranged at equal intervals, with a higher aspect ratio and strategically positioned center of gravity, along with a rolling bearing at the upper end of the shaft to enhance stability and minimize installation space, while maintaining high compression capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the compression capacity (air volume) of a hermetically sealed rotary compressor is increased, then the refrigeration capacity is improved, but the installation area becomes larger
Solution Approach 1:
The patent transitions from a conventional low aspect ratio configuration to a high aspect ratio configuration, effectively utilizing the vertical dimension to increase compression capacity while maintaining a compact horizontal footprint. This dimensional change allows the compressor to achieve higher refrigeration capacity without proportionally increasing the installation area.
2Productivity
If the compressor body is made larger to increase compression capacity, then the refrigeration capacity is improved, but the stability against loads and moments deteriorates
Solution Approach 1:
The patent employs an asymmetric support leg configuration where four support legs are positioned at unequal distances from the central axis. This asymmetric arrangement creates a lower center of gravity and optimizes the distribution of loads and moments, thereby enhancing stability despite the increased compressor size and higher center of gravity associated with high aspect ratio design.
Solution Approach 2:
The support legs are strategically positioned to act as counterweights that balance the increased toppling moment caused by the higher center of gravity in high aspect ratio compressors. The asymmetric placement of support legs creates restoring moments that counteract destabilizing forces.
3Area of stationary object
If the aspect ratio is increased to reduce installation area, then the compactness is improved, but the liability to topple under load increases
Solution Approach 1:
The asymmetric support leg configuration compensates for the increased toppling risk associated with high aspect ratio design. By positioning support legs at unequal distances from the central axis, the design creates a stable base that prevents toppling despite the elevated center of gravity.
Data Source
Figure 1
Figure 2~3A
Figure 3B
AI summary
Enlargement of an installation area is suppressed to make a compressor body (1) less liable to topple in such a manner that the overall height (H) measured from the bottom surfaces of support legs (2) is set to be 2.5 or more times as great as the outer diameter (D) of the compressor body (H/D ≥ 2.5), the height (Hg) of the center of gravity measured from the bottom surfaces of the support legs (2) to the center of gravity (G) is set to be 1/2 or less the overall height (H), and the support legs are provided in number of four, based on the fulfillment of Rc/cosθ < Rb < L. Here Rb is the support point radius of the compressor body (1), Rc is the outer radius of the compressor body (1), L is the distance from a longitudinal central axis (Oa) of the compressor body (1) to a longitudinal central axis (Ob) of an accumulator (4), and θ is an angle half the angle formed between the adjacent support legs (2) about the central axis (Oa).