Linear Motor Magnetic Circuit Design for Force Ripple Reduction
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Solution Overview
Problem
Conventional linear motors face issues with force ripple and increased load on supporting mechanisms due to discontinuous magnetic circuits, leading to vibration, noise, and reduced positioning accuracy, which are difficult to adjust and can vary with driving conditions.
Innovation Solution
The linear motor design features alternately arranged magnetic poles with a core that connects them, allowing for reduced leakage flux and adjustable force ripple by shifting the positions of magnetic poles, and incorporating multiple movers perpendicular to the travel direction to offset attraction and load on the supporting mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a rotating machine is cut open to create a linear motor with great attraction between mover and armature, then high driving force is achieved, but a great load is applied to the supporting mechanism and force ripple occurs due to discontinuous magnetic circuit
Solution Approach 1:
The armature is divided into multiple segments with independent magnetic poles, allowing the magnetic circuit to be optimized for continuity. Each segment can be independently designed to reduce force ripple while maintaining overall driving force, thus reducing the load on the supporting mechanism.
Solution Approach 2:
The patent introduces a new spatial arrangement by diagonally positioning auxiliary magnetic poles at the ends of the armature. This diagonal configuration creates a three-dimensional optimization of the magnetic circuit, improving continuity and reducing force ripple without compromising driving force.
2Manufacturing precision
If auxiliary magnetic poles are added to reduce force ripple, then nonuniformity of thrust is improved, but adjustment becomes difficult due to manufacturing errors and dispersion of characteristics
Solution Approach 1:
The auxiliary magnetic poles are deliberately positioned asymmetrically (diagonally) rather than symmetrically at the armature ends. This asymmetric configuration is designed to be more tolerant of manufacturing variations, reducing sensitivity to positioning errors and making the system more robust against dispersion of characteristics.
Solution Approach 2:
The patent optimizes the diagonal angle and position parameters of the auxiliary magnetic poles to achieve a balance between thrust uniformity and manufacturing tolerance. By carefully selecting these parameters, the system achieves good thrust uniformity while remaining insensitive to typical manufacturing variations.
3Power
If current increases to improve driving force, then attraction between armature and magnet increases, but armature and magnet deform and force ripple grows and varies with driving condition
Solution Approach 1:
Dividing the armature into multiple segments distributes the electromagnetic forces more evenly across the structure. This segmentation reduces the peak stresses and deformations in any single component, allowing higher overall current to be used without compromising structural stability.
Solution Approach 2:
The diagonal arrangement of auxiliary magnetic poles creates a more distributed force pattern in three-dimensional space. This spatial distribution reduces concentrated stresses and deformations, enabling the structure to maintain stability at higher driving forces.
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 reduces the load on supporting mechanisms, facilitates easier adjustment of force ripple, and enables miniaturization and lightening of the motor while maintaining reduced leakage flux and improved positioning accuracy.
Implementation Method 1
winding integrally wound onto the plural magnetic poles
Implementation Method 2
great attraction acts between a mover including a row of magnets and an armature
Implementation Method 3
a core that continuously connects the magnetic poles which hold the magnet of the mover between
Data Source
AI summary
The present invention provides a linear motor where a load onto a supporting mechanism and the ripple of force are lessened and the ripple can be adjusted. As a leakage flux between the magnetic poles can be reduced by being configured by plural magnetic poles arranged with a magnet arranged on a mover held between them, a core that continuously connects the magnetic poles that holds the magnet of the mover between them, windings are integrally wound onto the plural magnetic poles and the mover formed by a row of magnets the magnetic poles of which are alternately arranged or a row of magnets the polarity of which is alternately arranged and magnetic materials, by arranging the plural magnetic poles arranged with the magnet held between and the plural magnetic poles provided with the core that continuously connects the magnetic poles.