Actuator Yoke Design for Thrust and Mass Trade-off
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Solution Overview
Problem
Conventional actuators, such as voice coil motors, face challenges in achieving high thrust while minimizing the mass of magnetic field generating members like magnets and yokes, which affects their efficiency and size.
Innovation Solution
The actuator design incorporates a multipole-magnetized magnet with a yoke narrower than its surface, positioned to maximize magnetic flux and thrust, and a coil member to enhance magnetic field interaction, optimizing the shape of the yoke to reduce mass and increase thrust.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the yoke width is increased to match the magnet width, then the magnetic field generation is improved, but the mass of the magnetic field generating member increases
Solution Approach 1:
The yoke is designed with non-uniform thickness, being thicker at the center portion and thinner at the end portions. This local variation in quality allows the yoke to provide sufficient magnetic flux concentration at the center where it is most needed for thrust generation, while reducing material mass at the end portions where less magnetic flux is required. This resolves the contradiction by optimizing the distribution of yoke material rather than uniformly increasing or decreasing its dimensions.
2Force
If the yoke thickness is increased to improve magnetic flux concentration, then the thrust is improved, but the mass of the magnetic field generating member increases
Solution Approach 1:
The yoke thickness is varied locally, being greater at the center portion and smaller at the end portions. This local quality differentiation allows the yoke to concentrate magnetic flux effectively at the center region where the magnet and coil interaction is strongest, thereby maintaining high thrust generation. Simultaneously, the reduced thickness at the end portions decreases the overall mass of the magnetic field generating member, resolving the contradiction between thrust improvement and mass reduction.
3Volume of moving object
If the actuator size is reduced to minimize device dimensions, then the device compactness is improved, but the thrust generation capability is reduced
Solution Approach 1:
The non-uniform yoke thickness design concentrates the magnetic flux generation capability at the center portion where the thickness is greater. This allows the actuator to maintain effective thrust generation in a compact volume, as the magnetic field is most intense where needed (at the center) rather than being distributed uniformly throughout a larger structure. The reduced thickness at the end portions allows for overall size reduction while preserving thrust capability.
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 results in higher thrust with reduced mass, enabling smaller actuator sizes and improved precision in image blur correction devices, applicable to various devices like digital cameras and optical disk systems.
Implementation Method 1
an actuator including a magnetic field generating member having a multipole-magnetized magnet (631) and a yoke (641) disposed on a first surface of the multipole-magnetized magnet (631), and a coil member (651) provided in a position confronting a second surface of the multipole-magnetized magnet (631)
Implementation Method 2
a magnetic field generating member having a multipole-magnetized magnet (631)
Data Source
AI summary
Provided is an actuator that increases thrust while reducing mass of a magnetic field generating member including a magnet and a yoke, compared to conventional actuators. An actuator in the present disclosure includes a magnetic field generating member having a multipole-magnetized magnet and a yoke disposed on a first surface of the multipole-magnetized magnet, and a coil member provided in a position confronting a second surface of the multipole-magnetized magnet. The yoke is formed of a member narrower in width than the first surface of the multipole-magnetized magnet.