Loudspeaker Magnetic Circuit Fluid Containment
Solution Overview
Problem
Conventional loudspeakers face challenges in reducing magnetic fluid scattering due to voice coil amplitude and impact forces, especially in portable electronic devices that require high sound pressure and wide frequency range reproduction.
Innovation Solution
The loudspeaker design incorporates a magnetic circuit with cutout portions and holding portions to trap magnetic fluid, utilizing the magnetic force of an internal magnet to keep the fluid in place, reducing scattering and maintaining magnetic flux density, even under impact or vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If magnetic fluid is injected between the voice coil and center pole to reduce scattering, then reliability is improved, but device complexity increases due to additional holding portions and cutout portions
Solution Approach 1:
The internal plate is divided into multiple cutout portions that create separate holding portions for magnetic fluid. This segmentation allows the magnetic fluid to be contained in specific regions, preventing scattering while maintaining a relatively simple overall structure. The cutout portions are strategically positioned to address scattering issues without requiring complete structural redesign.
Solution Approach 2:
The magnetic fluid acts as an intermediary substance between the voice coil and magnetic circuit components. By injecting magnetic fluid into the holding portions created by the cutout portions, the patent reduces scattering effects without requiring direct mechanical constraints or complex structural modifications to the voice coil assembly.
2Power
If voice coil amplitude is increased for high sound pressure reproduction, then sound pressure characteristics are improved, but magnetic fluid scattering increases
Solution Approach 1:
The holding portions with magnetic fluid are prepared in advance within the magnetic circuit structure, before the voice coil operates. This preliminary configuration ensures that when the voice coil operates at high amplitude, the magnetic fluid is already contained and restrained, preventing scattering that would otherwise occur during high-power operation.
Solution Approach 2:
The magnetic fluid, which could potentially scatter and cause harm during high-amplitude operation, is instead utilized beneficially within the holding portions. The magnetic fluid serves to dampen vibrations and reduce scattering when properly contained, converting a potential harmful element into a beneficial damping medium that enables high sound pressure reproduction without scattering issues.
3Reliability
If impact resistance is improved by restraining magnetic fluid, then reliability is improved, but manufacturing precision requirements increase
Solution Approach 1:
Rather than requiring high precision throughout the entire magnetic circuit, the cutout portions are strategically positioned only where magnetic fluid containment is necessary. This local approach to quality control focuses manufacturing precision on specific critical areas (the cutout portion positions and shapes) while allowing less critical areas to have standard tolerances, thereby reducing overall manufacturing complexity.
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 enhances the loudspeaker's ability to resist input power, prevent temperature rise, and maintain sound pressure characteristics, ensuring high sound quality and reliability in small, portable devices.
Implementation Method 1
utilizing the magnetic force of an internal magnet to keep the fluid in place
Implementation Method 2
maintaining magnetic flux density, even under impact or vibration
Data Source
AI summary
A loudspeaker includes a bottom plate, an internal magnet, an internal plate, an external magnetic part, a frame, a diaphragm, and a voice coil. The internal plate includes a cutout portion so that the internal plate is smaller than the internal magnet when viewed from the top surface of the internal plate. Between the voice coil and the internal plate, there are a holding portion holding magnetic fluid and a void part having a void. The magnetic fluid is held in part of the cutout portion.