Flexible Loudspeaker Dustcap for Low-Profile High Excursion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Rigid dustcaps in loudspeakers increase the height of low-profile designs when the diaphragm is at its maximum extent in the forward direction, limiting the reduction of speaker height.
Innovation Solution
Employ a flexible dustcap with multiple corrugations that extends around the longitudinal axis, allowing the diaphragm to move without contacting the magnet unit or voice coil, thereby reducing the overall speaker height.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rigid dustcap is used to cover the hole in the diaphragm, then the dustcap effectively prevents dust and moisture from entering the magnet unit, but the height of the loudspeaker increases when the diaphragm is at its maximum extent in the forward direction
Solution Approach 1:
The dustcap is made from a flexible material instead of a rigid material, allowing it to deform when the diaphragm moves to its maximum extent in the forward direction. This flexibility enables the dustcap to clear the voice coil and magnet unit without contact, preventing height increase while maintaining protective function when the diaphragm is at rest or moving within normal range.
Solution Approach 2:
The dustcap transitions from a static, rigid structure to a dynamic, flexible structure that can adapt its position based on diaphragm movement. The flexible material allows the dustcap to dynamically clear the magnetic components during extreme diaphragm excursions while maintaining its protective covering function during normal operation.
2Length of stationary object
If the dustcap is made flexible to reduce speaker height, then the height is reduced, but the dustcap must still effectively prevent dust and moisture entry
Solution Approach 1:
The flexible material allows the dustcap to conform to space constraints and reduce overall height while maintaining continuous coverage over the hole in the diaphragm. The flexibility enables the dustcap to seal around the voice coil assembly without gaps that would compromise dust and moisture protection.
Solution Approach 2:
The material properties of the dustcap are changed from rigid to flexible, fundamentally altering its mechanical behavior. This parameter change allows the dustcap to achieve both reduced height and maintained protective function by adapting its shape and position while maintaining continuous coverage.
3Ease of manufacture
If a rigid dustcap is used, then the structure is simple and easy to manufacture, but it increases the height and may contact the voice coil or magnet unit during diaphragm movement
Solution Approach 1:
The flexible material can be formed into the required shape using relatively simple molding or forming processes, maintaining ease of manufacture. The single-piece flexible construction eliminates the need for complex assemblies or moving mechanisms, keeping production straightforward while achieving the height reduction goal.
Solution Approach 2:
Changing the material parameter from rigid to flexible simplifies the design by eliminating the need for complex mechanical clearance arrangements or adjustable mechanisms. The flexible material inherently provides the necessary clearance through deformation, reducing manufacturing complexity despite the material change.
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 flexible dustcap design achieves a reduced speaker height of 90 mm or less with a peak-to-peak excursion of 20 mm or more, maintaining effective sound production while minimizing the impact of the dustcap on height.
Implementation Method 1
a flexible dustcap which is configured to allow the diaphragm to be moved from a nominal position up to a maximum extent in a forward direction and a maximum extent in a backward direction
Implementation Method 2
the voice coil is configured to produce a magnetic field in use, wherein the magnetic field produced by the voice coil interacts with the magnetic field provided by the magnet unit in the air gap so as to move the diaphragm forwards and backwards
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A loudspeaker including a diaphragm having a front surface facing in a forward direction for producing sound to be radiated outwardly from the loudspeaker in the forward direction and a back surface facing in a backward direction that is opposite to the forward direction; a magnet unit configured to provide magnetic field in a predetermined region of space; a voice coil rigidly connected to the diaphragm, wherein the voice coil is configured to produce a magnetic field in use which interacts with the magnetic field provided by the magnet unit in the predetermined region of space so as to move the diaphragm along a longitudinal axis of the loudspeaker; a flexible dustcap attached to the diaphragm and an attachment surface of the loudspeaker that is fixed with respect to the magnet unit and is located radially inwards of the voice coil relative to the longitudinal axis of the loudspeaker.