Linear Compressor Virtual Pole Structure for Compact Reciprocation
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Solution Overview
Problem
Conventional transverse magnetic flux type reciprocating motors in linear compressors have limitations in mechanical stress, vibration distance, and friction loss due to the use of mechanical resonance springs, leading to increased height and reliability issues, as well as inefficiencies in magnetic interaction and assembly errors.
Innovation Solution
A linear compressor design that reduces the outer diameter of the transverse magnetic flux type reciprocating motor by stacking core plates in the axial direction, using a stator core with teeth portions and teeth shoes, and employing a magnet and virtual pole configuration to improve magnetic interaction stability and reduce friction, while eliminating mechanical resonance springs and separate bearings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If mechanical resonance springs are used in the transverse magnetic flux type reciprocating motor, then the motor can generate reciprocating motion, but the height of the linear compressor increases and reliability deteriorates due to mechanical stress limitations
Solution Approach 1:
The patent replaces the mechanical resonance spring system with an electromagnetic field-based reciprocating motor. The stator generates a rotating magnetic field that interacts with the rotor magnets to produce reciprocating motion without mechanical springs, thereby eliminating the height increase and reliability issues associated with mechanical resonance springs while maintaining the power generation function.
2Power
If mechanical resonance springs are used, then reciprocating motion is achieved, but friction loss increases and mechanical stress limits are reached
Solution Approach 1:
The patent eliminates mechanical friction by substituting the mechanical resonance spring system with an electromagnetic reciprocating motor. The electromagnetic field interacts with magnetic components to generate motion without physical contact and friction, thereby reducing energy loss while maintaining reciprocating motion capability.
3Power
If conventional transverse magnetic flux type reciprocating motor is used, then output is generated, but the outer diameter increases leading to increased height
Solution Approach 1:
The patent transitions from a conventional radial flux motor design to a transverse magnetic flux design where the magnetic field is generated in the axial direction rather than radially. This dimensional change in flux orientation allows for a more compact outer diameter while maintaining the required power output, as the magnetic interaction occurs along the axial axis rather than requiring a large radial footprint.
4Power
If magnets are used for magnetic interaction, then reciprocating motion is generated, but assembly errors may occur and stability is reduced
Solution Approach 1:
The patent uses virtual poles (N-shaped magnetic circuits) that create magnetic fields equivalent to physical poles without requiring precise placement of multiple magnets. The virtual pole structure replicates the magnetic interaction function while being more tolerant of assembly variations, thereby maintaining reciprocating motion generation while improving assembly stability and reducing errors.
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
The solution reduces the height of the linear compressor, enhances the stability of magnetic interaction, prevents assembly errors, and improves the axial movement stroke while minimizing friction and mechanical stress, resulting in a more reliable and efficient compressor.
Implementation Method 1
an inner stator coupled to an outer circumferential surface of the piston, and reciprocating in an axial direction by electromagnetic interaction with the coil
Implementation Method 2
a magnet disposed on the teeth shoe and facing the inner stator, and a virtual pole disposed on the teeth shoe, disposed in front or behind in an axial direction of the magnet, and facing the inner stator
Data Source
AI summary
A linear compressor includes a frame; an outer stator including a stator core disposed on the frame, a teeth portion extending inward from the stator core, and a teeth shoe extending in a circumferential direction from an inner end of the teeth portion; a coil disposed on the teeth portion; a cylinder disposed on the frame; a piston disposed in the cylinder; an inner stator coupled to an outer circumferential surface of the piston, and reciprocating in an axial direction by electromagnetic interaction with the coil; a magnet disposed on the teeth shoe and facing the inner stator; and a virtual pole disposed on the teeth shoe, disposed in front or behind in an axial direction of the magnet, and facing the inner stator. The outer stator includes a plurality of core plates stacked in the axial direction.