Linear Compressor Integrated Discharge Valve Motor Design
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Solution Overview
Problem
Linear compressors face challenges with increased size and weight due to the external location of the discharge valve assembly, which affects high-speed operation and efficiency, and there is a need to reduce the axial length of the motor and piston while maintaining motor output and preventing refrigerant leakage.
Innovation Solution
The compressor design integrates the suction valve, discharge valve, and discharge cover inside the motor and cylinder, allowing for a reduced piston length, coinciding the center of the supporting and eccentric forces for stable movement, and uses a gas bearing to provide a lifting force without oil, while preventing refrigerant leakage and heat transfer to the motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the discharge valve assembly is located outside the cylinder, then the discharge function is achieved, but the length of the shell and entire compressor increases
Solution Approach 1:
The discharge valve assembly is merged with the cylinder structure by positioning it at the end of the cylinder where the piston reaches its extreme position. The discharge valve, discharge spring, and muffler are integrated into the cylinder's terminal section, eliminating the need for a separate external discharge assembly and thereby reducing the overall compressor length.
2Power
If the cross section of the coil is increased to increase motor output, then the motor output increases, but the length of the piston and motor must increase
Solution Approach 1:
The coil cross-sectional area is increased by expanding in the radial dimension rather than the axial dimension. The motor is designed with a larger diameter to accommodate a bigger coil cross section, which increases motor output without increasing the axial length of the piston and motor assembly.
3Power
If the piston is lengthened to increase motor output, then the motor output increases, but the weight of the mover increases and high-speed operation becomes disadvantageous
Solution Approach 1:
Instead of increasing motor output by lengthening the piston axially, the design increases the coil cross-sectional area radially. This dimensional shift allows for higher power output while maintaining a shorter, lighter piston that is suitable for high-speed operation.
4Length of moving object
If the axial length of the motor is reduced, then the piston length is reduced, but it becomes difficult to maintain motor output and prevent refrigerant leakage
Solution Approach 1:
The motor design transitions from axial extension to radial expansion. By increasing the coil cross-sectional area in the radial direction rather than extending axially, the motor maintains its output power while achieving a shorter axial length that facilitates reduced piston length.
5Length of moving object
If the axial length of the motor is reduced, then the piston length is reduced, but it becomes difficult to prevent refrigerant leakage
Solution Approach 1:
The discharge valve assembly is merged with the cylinder structure at the piston's extreme position. This integration ensures that the discharge sealing function is maintained within the shortened axial length, as the discharge valve is positioned at the terminal section of the cylinder where it effectively seals the compression space.
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 design reduces the axial length of the motor, enhances motor output, improves compression efficiency, facilitates high-speed operation, and maintains stable piston movement, while also preventing refrigerant leakage and heat transfer to the motor, thus improving overall compressor efficiency.
Implementation Method 1
the permanent magnet is driven to linearly reciprocate by a mutual electromagnetic force between the permanent magnet and the inner (or outer) stator
Implementation Method 2
a mechanical resonance spring provided in a direction in which the mover moves accumulates a repulsive force while being compressed, and next the mechanical resonance spring having accumulated the repulsive force pushes the mover when the mover moves in an opposite direction
Data Source
Figure 1
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AI summary
The present disclosure relates to a linear compressor. A linear compressor according to an embodiment of the present disclosure includes: a cylinder defining a compression space for a refrigerant; a piston axially reciprocating inside the cylinder; a motor configured to provide a driving force to the piston; a discharge valve configured to discharge the refrigerant compressed in the compression space; and a discharge cover having a discharge space therein in which the refrigerant discharged through the discharge valve flows, wherein the discharge valve and the discharge cover are arranged inside the motor.