Monolithic Voice Coil Motor Structure for Higher Flux and Compact Travel
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Solution Overview
Problem
Traditional voice coil motor designs face limitations in space efficiency, force output, and manufacturing costs due to separate bearing and pole piece components, which result in reduced magnetic flux, increased component count, and assembly misalignments.
Innovation Solution
A monolithic structure integrating the pole piece and bearing components into a single component, allowing for a more compact design with improved magnetic field strength and reduced mass, enabling increased windings and enhanced force output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If separate bearing and pole piece components are used, then manufacturing and assembly are simplified, but space efficiency decreases and magnetic flux is reduced
Solution Approach 1:
The patent combines the bearing component and pole piece into a single integrated component. The bearing is formed with an integral pole piece structure, eliminating the need for separate components and their associated fasteners and assembly steps. This merging resolves the contradiction by maintaining manufacturing simplicity while significantly improving space efficiency and magnetic flux density.
Solution Approach 2:
The integrated component serves multiple functions simultaneously: it provides mechanical support through the bearing mechanism while also serving as a magnetic pole piece for flux concentration. This multi-functionality allows the single component to replace what would traditionally require separate bearing and pole piece components, thereby improving space efficiency without complicating manufacturing.
2Ease of repair
If separate bearing and pole piece components are used, then component replacement is easier, but assembly misalignments increase and force output decreases
Solution Approach 1:
By integrating the bearing and pole piece into a single monolithic component, the patent eliminates interface misalignments between separate parts. The integral structure ensures perfect alignment between the bearing raceway and pole piece magnetic flux paths, resolving the precision issue while maintaining ease of replacement at the component level.
3Reliability
If hardened high-carbon steel or stainless steel is used for bearings, then accuracy and lifetime are maximized, but magnetic field strength is reduced
Solution Approach 1:
The patent employs composite material construction where the bearing component is made from a material that combines the magnetic properties needed for pole piece functionality with the mechanical properties required for bearing performance. This composite approach allows the single component to achieve both high magnetic field strength and bearing reliability simultaneously.
Solution Approach 2:
The integrated component features locally optimized properties: the bearing regions have hardened surfaces for durability and precision, while the pole piece regions maintain high magnetic permeability for flux concentration. This local quality differentiation within the monolithic structure resolves the contradiction between bearing reliability and magnetic field strength.
4Volume of moving object
If a ring permanent magnet is used to nest the bearing, then space is saved, but magnetic flux and force output are reduced
Solution Approach 1:
The patent merges the bearing and pole piece into a single integral structure, achieving space savings without requiring a ring magnet configuration. This approach maintains the full magnetic flux path through a solid pole piece while still providing compact dimensions, thereby resolving the contradiction between space efficiency and magnetic force output.
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 monolithic design achieves space savings, improved force-to-weight ratio, reduced manufacturing costs, and enhanced performance by minimizing assembly misalignments and manufacturing tolerances, while maintaining or exceeding traditional motor efficiency.
Implementation Method 1
The interaction between two magnetic fields provides useful mechanical force output
Implementation Method 2
a high-permeability soft iron material is typically utilized to maximize the efficiency of the motor through improved magnetic flux
Data Source
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AI summary
A voice coil motor including: a magnet; a coil; a bobbin supporting a winding of the coil and arranged coaxially with and radially outside of the magnet; a bearing housing including a first part of a linear bearing; a monolithic structure including a pole piece housing and a second part of the linear bearing; wherein the pole piece housing includes a sidewall, closed and open ends, and is arranged coaxially with and radially outside of the bobbin; the closed end is attached to the magnet; the bearing housing and an end of the bobbin are fixed relative to a common structure; the pole piece housing and the bearing housing are arranged to cause the first and second parts of the linear bearing mechanism to engage such that when a current is applied to the coil, the pole piece housing moves relative to the common structure.