Split Magnet Loudspeaker Flux Concentration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Loudspeakers with single thick magnets supported by conductive pedestals suffer from increased fringe magnetic fields, non-linear voice coil motor force constants, and higher manufacturing costs, leading to reduced efficiency and distorted performance.
Innovation Solution
A loudspeaker design utilizing split multiple magnets with aligned polarities, a core, magnet housing, and core cap to concentrate magnetic flux within a voice coil gap, reducing fringe fields and improving voice coil motor force constant linearity, while maintaining magnetic flux density across the air gap.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a single thick magnet is used to provide sufficient magnetic flux, then the magnetic flux density is improved, but fringe magnetic fields increase and efficiency decreases
Solution Approach 1:
The single thick magnet is divided into multiple thinner magnets (first magnet and second magnet) stacked together. This segmentation reduces the fringe magnetic fields generated by each individual magnet while maintaining the total magnetic flux density required for efficient operation.
2Manufacturing precision
If a single thick magnet is used to achieve desired magnetic flux, then the magnetic flux density is improved, but the voice coil motor force constant becomes non-linear and distortion increases
Solution Approach 1:
Dividing the magnet into multiple thinner magnets creates a more uniform magnetic flux distribution across the air gap. This uniformity ensures that the voice coil experiences consistent magnetic field strength throughout its travel range, resulting in a linear motor force constant and reduced distortion.
Solution Approach 2:
Each individual magnet in the stack is designed with specific local magnetic properties that, when combined, create an overall uniform magnetic field. The local quality of each magnet is optimized to contribute equally to the total flux, ensuring linearity across the entire magnetic circuit.
3Quantity of substance
If a single thick magnet is used to provide sufficient magnetic flux, then the magnetic flux density is improved, but the loudspeaker mass increases and manufacturing costs increase
Solution Approach 1:
The magnetic flux requirement is divided across multiple thinner magnets rather than requiring one thick magnet. This segmentation reduces the total material volume and weight while maintaining the necessary total magnetic flux through the stacked configuration.
Solution Approach 2:
The magnet assembly uses a composite structure of multiple magnet materials stacked together, potentially combining different magnetic material properties to achieve the required flux density with reduced overall mass compared to a single thick magnet of equivalent performance.
4Quantity of substance
If a single thick magnet is used to achieve desired magnetic flux, then the magnetic flux density is improved, but manufacturing and shipping costs increase
Solution Approach 1:
Manufacturing multiple thinner magnets is more cost-effective than producing one thick magnet. The segmented magnets can be manufactured using standard processes, assembled in stacks, and shipped more efficiently, reducing overall manufacturing and logistics costs while maintaining required magnetic flux.
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 design achieves improved voice coil movement accuracy and overall loudspeaker performance with reduced weight and manufacturing costs, providing more linear voice coil motor force constants and decreased distortion across a wider frequency range.
Implementation Method 1
Magnetic flux produced by the first and second magnets may be combined, directed, and/or concentrated by the core cap and magnet housing within the voice coil gap
Implementation Method 2
When electrical energy flows into the voice coil, an induced magnetic field can be created that interacts with the magnetic flux in the voice coil gap
Implementation Method 3
the interaction between the voice coil current and the magnetic flux can cause linear oscillation of the voice coil within the length of the voice coil gap
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A loudspeaker can provide magnetic flux from polarity-aligned split magnets to drive voice coils and generate sound. The loudspeaker may have reduced stray magnetic fields and a BL curve with symmetric and linear characteristics. The loudspeaker can include a core, split magnets, a magnet housing, a core cap, and a voice coil gap formed between the magnet housing and the core cap. Magnetic flux produced by the split magnets may be combined, directed, and/or concentrated by the core cap and magnet housing within the voice coil gap. At least portions of a voice coil may be positioned within the voice coil gap and a diaphragm may be coupled to the voice coil. A bucking magnet assembly may contain a magnetic flux of the magnet structure to further improve performance. The bucking magnet assembly may include split magnets with an aligned polarity that is opposite the polarity of the magnet structure.