Hermetic Compressor Piston Segmentation to Reduce Sliding Loss
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Solution Overview
Problem
Hermetic compressors face challenges in improving lubricity and compression efficiency while reducing sliding loss, as the existing designs result in increased friction and wear due to the larger sliding area of the piston, leading to inefficiencies and potential hermeticity issues.
Innovation Solution
The design incorporates a piston with a columnar seal section, extension sections, and a capture section, where the extension sections have circular arc faces matching the seal section's radius, and the capture section extends further with a smaller radius, reducing the sliding area and enhancing lubrication, thereby minimizing friction and wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the piston has a larger sliding area to improve sealing, then compression efficiency is improved, but sliding loss increases
Solution Approach 1:
The piston is divided into multiple functional sections: a seal section with larger radius for sealing, extension sections for structural support, and a capture section with smaller radius. This segmentation allows the sealing function to be concentrated in a specific area rather than requiring the entire piston surface to be in contact with the cylinder wall, thus improving compression efficiency while reducing overall sliding loss.
Solution Approach 2:
Different sections of the piston are given different radii and functions. The seal section has a larger radius to ensure proper sealing contact with the cylinder wall, while the capture section has a smaller radius to reduce sliding area and friction. This local differentiation of properties allows the piston to optimize both sealing performance and friction reduction simultaneously.
2Loss of energy
If the piston sliding area is reduced to decrease sliding loss, then energy efficiency is improved, but lubricity and sealing may deteriorate
Solution Approach 1:
The piston structure is segmented into a seal section that maintains adequate contact area for proper sealing and lubrication, and a capture section with reduced radius that minimizes sliding loss. By concentrating the sealing function in the seal section with appropriate dimensions, the patent ensures reliable lubricity and sealing while the reduced capture section minimizes energy loss through friction.
Solution Approach 2:
The extension sections act as intermediaries that connect the seal section and capture section, providing structural support and ensuring proper load distribution. This intermediary structure allows the capture section to have reduced radius for lower friction while the seal section maintains adequate size for proper sealing and lubrication.
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
This configuration improves lubricity and compression efficiency while significantly reducing sliding loss, maintaining hermeticity and enhancing the overall performance of the hermetic compressor and refrigerator.
Implementation Method 1
a columnar seal section in sliding contact with an inner peripheral face of the cylinder
Implementation Method 2
lubricating oil passes through the oil supply hole, and fills a gap between the outer peripheral face of the piston and the inner peripheral face of the cylinder chamber. This lubricating oil lubricates the portion between the piston and the cylinder chamber
Data Source
AI summary
A hermetic compressor (100) includes an electric element (110), a compression element (112), and a hermetic container (102). The compression element includes a shaft (118), a cylinder block (124), a piston (136), a connection section (144), and an oil supply mechanism (130). The piston has a columnar seal section (160) in sliding contact with an inner peripheral face of the cylinder, two extension sections (162) that have circular arc faces each having the same radius as a radius of the seal section and extend from the seal section to the bottom dead center side in the axial direction with a circumferential gap therebetween, and a columnar capture section (164) that extends further toward the bottom dead center side than the extension section and has a smaller radius than the radius of the seal section.