Magnet Assembly Suspension for Drop Impact Absorption
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Solution Overview
Problem
Conventional moving magnet actuators in audio speakers are prone to damage when dropped due to the fragility of the voice coil and magnets, leading to mechanical stress-related failures.
Innovation Solution
The development of actuator modules with improved damage resistance, featuring a baseplate, voice coil, magnet assembly, and a rigid frame with springs that dissipate force upon impact, preventing damage by allowing the voice coil to extend into an air gap and facilitating a rocking mode that absorbs the impact energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the voice coil and magnets are made fragile for precise audio performance, then the audio quality is improved, but the actuator becomes prone to drop damage
Solution Approach 1:
The patent implements a suspension system with compliant elements (springs and foam material) that are pre-configured to cushion and absorb impact forces before they reach the fragile voice coil and magnets. This beforehand cushioning allows the actuator to maintain precise audio performance components while protecting them from drop damage through the energy-absorbing suspension mechanism.
2Stability of the object's composition
If a rigid suspension system is used to support the magnet assembly, then structural stability is improved, but impact forces are transmitted directly to the voice coil and magnets
Solution Approach 1:
The patent changes the physical parameters of the suspension system by using compliant elements with specific mechanical properties (spring constants, foam density) that allow the structure to maintain stability during normal operation while absorbing impact forces. The suspension system's compliance parameters are optimized to provide structural support during audio playback while dissipating energy from drops.
3Length of moving object
If the springs are attached at the furthest extent of the magnet assembly, then the suspension range is maximized, but the connection points become vulnerable to stress concentration
Solution Approach 1:
The patent applies local quality by providing reinforcement features specifically at the connection points where springs attach to the magnet assembly. This may include localized strengthening of the magnet assembly structure at attachment locations, allowing the springs to be positioned at optimal locations for suspension range while the reinforced connection points resist stress concentration and prevent failure.
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 actuator modules significantly reduce the likelihood of failure from mechanical stress caused by drops, ensuring the components remain functional and intact, while maintaining the necessary frequency response for audio production.
Implementation Method 1
a pair of springs suspending the magnet assembly relative to the frame and baseplate
Implementation Method 2
The pair of springs including a first spring shaped as a loop defining an aperture sized to accommodate motion of the magnet assembly along a direction of the coil axis
Implementation Method 3
a voice coil connected to the baseplate, the voice coil defining a coil axis perpendicular to the plane
Data Source
AI summary
An actuator module includes a baseplate extending in a plane, a voice coil connected to the baseplate, and a magnet assembly. The actuator module also includes a rigid frame attached to the baseplate, the rigid frame comprising four stubs. The actuator module further includes a pair of springs suspending the magnet assembly relative to the frame and baseplate so that the voice coil extends into the air gap, the pair of springs including a first and second spring each shaped as a loop defining an aperture sized to accommodate motion of the magnet assembly along a direction of the coil axis, the first spring being attached to the frame at a first pair of the four stubs, the second spring being attached to the frame at a second pair of the four stubs, and both being attached to separate portions of the magnet assembly.