Linear Compressor Ferrite Magnet Flux Shielding
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Solution Overview
Problem
Conventional linear compressors using rare earth magnets are costly due to high magnetic flux density and suffer from efficiency deterioration due to magnetic flux leakage, and face reliability issues during uncontrolled reciprocation where lighter components are more prone to breakage due to inertial forces.
Innovation Solution
A linear compressor design utilizing a ferrite permanent magnet with a cylindrical magnet frame and a fixing plate, where the magnet assembly with greater mass collides with stationary components during emergencies, and non-magnetic aluminum materials for the cylinder and piston to prevent magnetic flux leakage, along with a support structure to manage reciprocation and reduce noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If rare earth permanent magnets are used to provide high magnetic flux density, then the driving force of the linear motor is improved, but the manufacturing cost increases and magnetic flux leakage occurs causing efficiency deterioration
Solution Approach 1:
The patent changes the material parameter of the permanent magnet from rare earth materials to ferrite materials. Although ferrite has lower magnetic flux density, the design compensates through optimized magnet assembly structure and positioning, achieving sufficient driving force while dramatically reducing manufacturing cost and eliminating magnetic flux leakage issues.
2Ease of manufacture
If the permanent magnet is made lighter to reduce cost, then manufacturing cost is reduced, but reliability decreases during uncontrolled reciprocation due to greater inertial forces on lighter components
Solution Approach 1:
The patent designs a magnetic flux shielding structure and support framework that acts as a protective cushion during uncontrolled reciprocation. The shielding structure includes magnetic flux shields positioned between the permanent magnet and stationary components, preventing direct impact and absorbing shock forces, thereby protecting the lighter ferrite magnet from breakage during emergency conditions.
3Reliability
If the permanent magnet is made heavier to improve reliability during reciprocation, then breakage resistance is improved, but manufacturing cost increases due to use of rare earth materials
Solution Approach 1:
The patent employs composite material strategy by combining ferrite permanent magnets with magnetic flux shielding materials and structural support components. The shielding structure and support framework work together to provide the protective function that would otherwise require a heavier magnet, achieving reliability improvement through material composition rather than mass increase.
4Ease of manufacture
If ferrite permanent magnet is used instead of rare earth magnet, then manufacturing cost is reduced and magnetic flux leakage is minimized, but driving force may be reduced
Solution Approach 1:
The patent introduces magnetic flux shields as intermediary components between the ferrite permanent magnet and the motor stator. These shields optimize the magnetic flux distribution and enhance the interaction between the magnet and stator coils, compensating for the lower inherent magnetic flux density of ferrite materials and maintaining sufficient driving force.
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 design enhances compression efficiency, reduces manufacturing costs, and improves reliability by minimizing breakage risks and magnetic flux leakage, while maintaining operational efficiency and cost-effectiveness.
Implementation Method 1
The linear motor may include an outer stator 2 fixed to the frame 5, and arranged to surround the cylinder 6, an inner stator 3 spaced from an inner side of the outer stator 2, and a permanent magnet 10 placed in a space between the outer stator 2 and the inner stator 3. The outer stator 2 may include a winding of coil 4.
Implementation Method 2
A spring (not illustrated) may be engaged between the supporter 8 and the motor cover 9. The spring may have natural frequency which is so adjusted to allow the piston 7 to resonate.
Implementation Method 3
The linear compressor 1 may include a muffler 12 which extends from interior of the piston 7 to outside. The muffler 12 deadens noise generated from refrigerant flow.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A linear compressor (10) includes a shell (100a) which comprises a refrigerant suction part (101), a cylinder (120) provided within the shell, a piston (130) which reciprocates within the cylinder, a motor assembly (200) which provides a driving force for a motion of the piston, a support member (315) provided to the magnet assembly, to support an end of the permanent magnet (350), and a frame (110) which is engaged with the cylinder to support the motor assembly, and which comprises a contact part (110a) to absorb impact when the piston collides against the support member.