Two-Phase Linear Motor Coil Optimization for Thrust Density
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Solution Overview
Problem
Conventional linear motors face limitations in increasing thrust and stroke length due to magnetic saturation, especially when driving larger lenses in imaging devices, where higher thrust and longer movement are required.
Innovation Solution
A two-phase linear motor design with a specific coil and magnet configuration, where the winding width and average width of the coil are optimized within certain electrical angle ranges, and the pitch between coils is set to reduce harmonic components in the magnetic flux, thereby increasing thrust density and allowing for a longer stroke without magnetic saturation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the coil winding width and average width are increased to increase thrust, then magnetic saturation occurs which limits further stroke lengthening
Solution Approach 1:
The patent applies parameter changes by optimizing the coil winding width to be 0.6-0.8 times the magnet width and the average coil width to be 0.8-1.0 times the magnet width. These specific parameter ranges maximize thrust density while preventing magnetic saturation, resolving the contradiction between increasing force and maintaining reliability.
2Length of moving object
If the stroke length is increased to accommodate larger lenses, then magnetic saturation occurs which reduces thrust
Solution Approach 1:
The patent resolves this contradiction by changing the magnetic circuit design parameters, specifically setting the air gap to 0.1-0.3 times the magnet width and optimizing the yoke thickness. These parameter changes enable longer stroke lengths while maintaining sufficient thrust by preventing magnetic saturation in the extended magnetic path.
3Force
If the coil dimensions are optimized to increase thrust density, then the motor size increases which may not be suitable for compact imaging devices
Solution Approach 1:
The patent optimizes the ratio parameters rather than absolute dimensions, setting the coil winding width to 0.6-0.8 times the magnet width and average coil width to 0.8-1.0 times the magnet width. This ratio-based optimization achieves high thrust density while maintaining a compact overall motor size suitable for imaging devices.
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 enhances thrust density, reduces harmonic components leading to less vibration and noise, and enables precise positioning, making it suitable for larger lenses in imaging devices.
Implementation Method 1
a linear motor driven in two phases, and comprises a two-phase coil and a magnet that is disposed along the drive direction at a position opposite the two-phase coil
Data Source
AI summary
A focusing unit (1) comprises a linear motor driven in two phases, and comprises a two-phase coil (10a, 10b) and a drive magnet (9) that is disposed along the drive direction at a position opposite the two-phase coil (10a, 10b). The winding width of the coils (10a, 10b) in the portion opposite the drive magnet (9) is within an electrical angle range of 120°±7.7°, the average width of the coil at the portion opposite the drive magnet (9) is within an electrical angle range of 144°±4.6°, and the pitch between the two phases of coil (10a, 10b) is an electrical angle of 90°+180°×n (n is an integer of 0 or more).