Linear Compressor Gas Pocket Elliptical Shape Levitation
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Solution Overview
Problem
Conventional linear compressors using gas bearings face challenges with levitation force and leakage of high-pressure gas, leading to increased size and potential damage to the piston due to inefficient gas pocket design, which affects compressor efficiency and longevity.
Innovation Solution
The design incorporates a gas pocket with a longer axial length and reduced circumferential length, featuring an elliptical or rectangular shape with rounded corners, and strategically positioned gas holes to minimize contact area and leakage, enhancing levitation force and reducing piston damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the gas pocket cross-sectional area is increased to secure effective bearing area, then the levitation force is improved, but the gas leakage between cylinder and piston increases
Solution Approach 1:
The gas pocket cross-sectional shape is changed from circular to elliptical, with the long axis extending in the axial direction. This dimensional reconfiguration allows the gas pocket to achieve sufficient bearing area through increased axial length while reducing circumferential width, thereby minimizing leakage paths between the cylinder and piston while maintaining effective levitation force.
2Force
If the gas pocket cross-sectional area is increased to secure effective bearing area, then the levitation force is improved, but the orthogonal area between piston and gas pocket increases causing piston damage
Solution Approach 1:
The gas pocket is designed with an elliptical cross-section where the long axis is in the axial direction and the short axis is in the circumferential direction. This reorientation allows the gas pocket to achieve sufficient bearing area primarily through axial extension rather than circumferential expansion, thereby reducing the orthogonal contact area with the piston and minimizing damage during reciprocating motion.
Solution Approach 2:
The gas pocket cross-section is designed as an asymmetric ellipse rather than a symmetric circle, with deliberately different dimensions in the axial and circumferential directions. This asymmetric configuration optimizes the distribution of bearing area to maximize levitation force while minimizing harmful orthogonal contact with the piston surface.
3Productivity
If the gas hole is formed narrow to control gas flow, then the gas bearing efficiency is improved, but the manufacturing precision requirements increase
Solution Approach 1:
Instead of requiring uniform narrow dimensions throughout the gas hole, the design allows the gas hole to have an elliptical cross-section with different dimensions in different directions. The gas hole can be narrower in the circumferential direction to control leakage while being longer in the axial direction to maintain flow efficiency, reducing overall manufacturing precision requirements through directional differentiation.
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 increases the levitation force, minimizes gas leakage, and reduces piston damage, resulting in a more efficient and compact compressor with improved operational stability.
Implementation Method 1
high pressured gas discharged from a compression space is supplied to a bearing surface to help a piston float against a cylinder by a pressure of the discharged refrigerant
Implementation Method 2
a conventional gas bearing method in which high pressured gas discharged from a compression space is supplied to a bearing surface
Data Source
AI summary
A linear compressor includes: a piston configured to reciprocate in an axial direction, and a cylinder that is provided on a radially outer side of the piston to accommodate the piston and that defines a compression space with the piston. The cylinder includes: a gas hole defined at the cylinder such that a first end of the gas hole is at an outer circumferential surface of the cylinder and a second end of the gas hole is at an inner circumferential surface of the cylinder, and a gas pocket that is in communication with the gas hole and that is recessed from the inner circumferential surface of the cylinder, where a length of the gas pocket in the axial direction of the cylinder is longer than a length of the gas pocket in a circumferential direction of the cylinder.