Vibration Motor Halbach Array Magnet Design
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Solution Overview
Problem
Existing vibration motors face challenges in increasing magnetic force without increasing the thickness of the top plate portion, which hinders their responsiveness and ability to provide sharp start and stop functions required for tactile feedback applications.
Innovation Solution
The vibration motor incorporates a magnet with a Halbach array structure, comprising first and second magnets arranged to generate magnetic forces in opposite directions, allowing for increased magnetic force without increasing the top plate thickness, thereby enhancing responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the magnetic force is increased by using large magnets, then the responsiveness of the vibration motor is improved, but the thickness of the top plate portion must be increased to form a magnetic path, which increases the overall thickness
Solution Approach 1:
The patent transitions from a conventional single-magnet configuration to a Halbach array configuration with multiple magnets arranged in a specific two-dimensional pattern. This dimensional arrangement allows magnetic flux to be directed more efficiently through the top plate portion, forming a complete magnetic path without increasing the plate's thickness. The magnets are positioned at different locations and orientations within the same plane, creating a composite magnetic field that achieves higher effective magnetic force while maintaining the same overall thickness profile.
Solution Approach 2:
The patent employs a composite magnetic structure consisting of multiple permanent magnets with different polarities arranged in a Halbach array pattern. This composite arrangement combines the magnetic fields of individual magnets to create a unified, enhanced magnetic field distribution. The top plate portion acts as a composite magnetic circuit element that channels flux from multiple magnet sources, achieving superior magnetic force transmission without requiring increased thickness of any single component.
2Force
If the thickness of the top plate portion is increased to form a magnetic path, then the magnetic force is increased, but the thickness of the entirety of the vibration motor is increased
Solution Approach 1:
Instead of increasing thickness in the vertical dimension to create a magnetic path, the patent utilizes the horizontal plane dimension by arranging multiple magnets in a Halbach array configuration. This allows the magnetic flux to travel laterally through the top plate portion and return through the housing, creating a complete magnetic circuit without requiring vertical thickness increase. The magnetic path is formed through strategic positioning and orientation of magnets within the existing thickness constraints.
Solution Approach 2:
The patent divides the magnetic field generation function into multiple discrete magnet segments arranged in a Halbach array, rather than relying on a single large magnet or a single thick magnetic path. Each magnet segment contributes to the overall magnetic field in a specific direction, and their combined effect creates a strong, focused magnetic field. This segmentation allows the magnetic flux to be distributed and channeled through multiple thinner pathways in the top plate portion, achieving the required magnetic force without increasing overall thickness.
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 enables faster starting and stopping of the vibration motor while maintaining a reduced thickness, making it suitable for applications requiring high responsiveness, such as tactile feedback.
Implementation Method 1
When driving the vibration motor, a magnetic field is generated between the magnets and the coil, and the vibrating body vibrates
Implementation Method 2
an elastic member located between the stationary portion and the vibrating body
Data Source
AI summary
A vibration motor includes a stationary portion including a casing and a coil; a vibrating body including a weight and a magnet, the vibrating body being supported so as to be vibratable in one direction relative to the stationary portion; an elastic member located between the stationary portion and the vibrating body; and a top plate portion that is disposed above the vibrating body in an up-down direction that is perpendicular to the one direction. The magnet is disposed above the coil, and the top plate portion faces the magnet in the up-down direction. The magnet includes a set of first magnets that generate magnetic forces that are opposite to each other in the up-down direction and one or more second magnets that are interposed between the first magnets and each generate a magnetic force in the one direction.