Grooved Pole Piece Structure for Linear Vibration Distortion
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Solution Overview
Problem
Linear vibration motors in mobile devices experience vibration distortion due to magnetic attraction forces acting along non-vibration directions, leading to suboptimal vibration feedback.
Innovation Solution
The design includes a housing with a vibration unit and a driving unit featuring a weight with a magnet and elastic member, pole pieces fixed along the vibration direction, and a groove on the pole piece surface facing the magnet to increase distance and reduce magnetic attraction force, thereby minimizing vibration distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the pole piece is polarized when the coil is powered on, then the magnetic attraction force is generated, but the magnetic attraction force acts along a non-vibration direction causing vibration distortion
Solution Approach 1:
The patent extracts the harmful magnetic attraction force component by introducing a groove on the pole piece surface facing the magnet. This groove structure removes material from the pole piece, thereby reducing the magnetic attraction force that acts perpendicular to the vibration direction, while preserving the necessary magnetic force for vibration generation along the intended axis.
Solution Approach 2:
The groove is strategically positioned only on the portion of the pole piece that faces the magnet, creating a localized modification. This local quality change reduces magnetic attraction force specifically in the region where it causes harmful non-vibration direction forces, while leaving other regions of the pole piece unchanged to maintain overall structural integrity and necessary magnetic field distribution.
2Manufacturing precision
If the groove is formed on the pole piece surface facing the magnet, then the magnetic attraction force is reduced, but the pole piece structure becomes more complex
Solution Approach 1:
The groove introduces a segmented or divided structure on the pole piece surface, creating distinct regions with different magnetic properties. This segmentation allows the pole piece to have varying magnetic attraction characteristics across its surface, reducing harmful forces in specific areas while maintaining necessary forces in other areas, thereby improving vibration direction accuracy.
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 vibration distortion and enhances the vibration ability of the linear vibration motor, providing more accurate and effective feedback in mobile devices.
Implementation Method 1
a coil wound around the iron core
Implementation Method 2
the pole piece is polarized, resulting in magnetic attraction force
Implementation Method 3
an elastic member configured to suspend the weight in the accommodation space
Data Source
AI summary
The present disclosure discloses a linear motor having a housing with an accommodation space, a vibration unit and a driving unit received in the accommodation. The vibrator unit includes a weight with a receiving space and a magnet unit fixed on the weight and inside the receiving space. The driving unit includes an iron core received in the receiving space, two pole pieces respectively fixed on two opposite ends of the iron core along a vibration direction and a coil wound around the iron core. A groove is provided on the pole piece and faces the magnet unit along a first direction perpendicular with the vibration direction. The distance between the pole piece and the magnet unit increases, effectively decreasing the magnetic attraction force between the pole piece and magnet unit and avoiding the non-linear vibration of the linear vibration motor.