Multi-Stage Loudspeaker Suspension for Linear Displacement
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Solution Overview
Problem
Conventional loudspeaker suspension systems lack the ability to achieve a multi-stage stiffness curve, leading to limitations in displacement capability, material damage, and distortion due to non-linear stiffness, which results in instability and premature failures.
Innovation Solution
A multi-stage mechanical suspension system comprising a flexible rear spider, surround, and diaphragm, combined with a contactor arrangement that includes a contactor and contact receivers, allowing for a linear stiffness at low displacements and a non-linear stiffness at higher displacements, preventing over-excitation and material damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional flexible connections are used with all connections always connected, then the restoring force is provided continuously, but the ability to shape the stiffness versus deflection curve is limited and displacement capability is restricted
Solution Approach 1:
The suspension system is divided into multiple independent flexible connections (first flexible connection, second flexible connection, third flexible connection) that can be selectively engaged or disengaged. This segmentation allows the system to provide different stiffness characteristics at different displacement ranges, enabling multi-stage stiffness control while maintaining manageable system complexity through modular design.
Solution Approach 2:
The suspension system transitions from a static configuration where all connections are always connected to a dynamic configuration where flexible connections can be selectively engaged or disengaged based on displacement conditions. This dynamic adaptability allows the system to optimize stiffness characteristics for different operating conditions, thereby increasing displacement capability without excessive complexity.
2Length of moving object
If the suspension system is designed to have correct stiffness at near zero displacement, then the resonant frequency is correct, but the displacement capability is limited by physical space and potential damage to moving parts
Solution Approach 1:
The suspension system uses segmented flexible connections that can be selectively engaged to provide appropriate stiffness at different displacement stages. The first flexible connection provides stiffness at low displacements for correct resonant frequency, while the second and third flexible connections can be engaged at higher displacements to provide additional restoring force and prevent over-excitation, thereby protecting the system without limiting normal displacement capability.
Solution Approach 2:
The suspension system incorporates pre-designed flexible connections that are prepared to engage at specific displacement thresholds. These connections act as pre-arranged protective measures that automatically engage when displacement exceeds safe limits, providing beforehand cushioning against over-excitation and potential damage to moving parts.
3Reliability
If the suspension system undergoes break-in, then the suspension becomes less stiff due to material wear, but the transducer becomes vulnerable to over-excitation and potential damage
Solution Approach 1:
The suspension system uses multiple independent flexible connections that can compensate for the stiffening effect of break-in. As the primary flexible connection becomes less stiff due to material wear, additional flexible connections can be engaged to maintain the required restoring force and prevent over-excitation, thereby ensuring continuous reliability without excessive complexity.
Solution Approach 2:
The suspension system changes its effective stiffness parameters by selectively engaging or disengaging different flexible connections. This allows the system to adapt to parameter changes caused by break-in and material wear, maintaining appropriate stiffness characteristics and protection against over-excitation throughout the product lifecycle.
4Reliability
If a non-linear stiffness curve is used to prevent over-excitation, then displacement is limited, but distortion increases due to non-linear stiffness
Solution Approach 1:
The suspension system segments the stiffness function across multiple flexible connections that engage at different displacement stages. The first flexible connection provides linear stiffness for normal operation, minimizing distortion. The second and third flexible connections engage only at higher displacements to provide non-linear stiffness for protection, thereby limiting over-excitation while minimizing distortion during normal linear operation.
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 multi-stage suspension system enhances displacement capability, reduces distortion, and prevents material damage by controlling stiffness, ensuring stable operation and extended lifespan of the loudspeaker.
Implementation Method 1
The restoring force is provided by flexible, spring-like connections between the diaphragm and the stationary parts of the loudspeaker
Implementation Method 2
This alternating current (AC) signal creates a current in the coil that generates a force equal to B*l*i (where B = the permanent magnetic field strength, l = the length of wire in the coil immersed in the permanent magnetic field, and i = the current flowing in the coil)
Data Source
Figure 1~2
Figure 3~5
Figure 6
AI summary
A multi-stage mechanical suspension system extends a linear operating range for a loudspeaker and prevents mechanical damage on explosive peaks. The system includes a pair of spaced contact receivers that limit the travel of a contactor. The system provides a flat linear response at low frequencies as the contact receivers are intermittently or occasionally contacted by the contactor during operation of the loudspeaker. The system enables creation of different regions of non-linearity within a total stiffness versus deflection curve of a loudspeaker suspension system. The non-linearity in each region can be controlled individually, so long as the non-linearity by region increases moving away from the rest position. Thus, a plateau of substantially linear stiffness may extend for a large portion of the total displacement allowed for a voice coil and suspension components before a region of non-linear stiffness occurs only at the ends of an allowable excursion to limit the motion. More than two regions of stiffness also can be created to achieve maximum performance and stability.