Loudspeaker Compliant Guide Structure for Silent Axial Motion
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Solution Overview
Problem
Existing loudspeakers face issues with guide systems that are noisy, prone to mechanical failure, and lack sufficient stiffness in transverse directions, while also being bulky, heavy, and costly to manufacture.
Innovation Solution
A loudspeaker design featuring a ferromagnetic circuit with a central and outer core, a movable magnet within a gap, and a compliant mechanism with flexible parts and rigid connecting portions that guide the magnet's movement along a specific direction using tension and compression, ensuring high rigidity orthogonal to the motion direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional guide system (spider or retaining bands) is used, then the loudspeaker can be manufactured with conventional methods, but the guide system breaks easily, creates noise, and lacks sufficient transverse rigidity
Solution Approach 1:
The patent replaces the traditional mechanical guide system (spider or retaining bands) with a magnetic guide system. The magnetic guide system uses magnetic fields generated by fixed coils to guide the movement of the movable magnet assembly, eliminating mechanical contact and friction. This substitution resolves the contradiction by providing a contactless guidance mechanism that does not wear out, creates no noise, and maintains high reliability while ensuring transverse rigidity through magnetic field control.
Solution Approach 2:
The patent introduces magnetic fields as an intermediary between the fixed and movable components. The magnetic fields act as a mediator to transmit force and guide movement without direct mechanical contact. This intermediary approach allows the movable magnet assembly to be guided precisely along the desired path while avoiding the mechanical wear and noise associated with traditional guide systems.
2Ease of operation
If retaining bands with flattened portions are used to guide movement, then the loudspeaker allows axial movement, but the flattened portions deform transversely reducing constraint effectiveness
Solution Approach 1:
The patent replaces the mechanical retaining band system with a magnetic guide system that uses electromagnetic fields to constrain movement. The magnetic fields generated by fixed coils create a virtual guide structure that maintains transverse rigidity without physical contact. This allows the movable magnet assembly to move freely along the axial direction while being strongly constrained in transverse directions through magnetic field gradients, eliminating the deformation issues of physical retaining bands.
3Ease of manufacture
If conventional guide systems are used, then the loudspeaker can be assembled with standard components, but the system becomes bulky, heavy, and expensive
Solution Approach 1:
The patent makes the fixed coils serve multiple functions: they generate the magnetic field for the moving magnet assembly and simultaneously provide the guiding function. This multi-functionality eliminates the need for separate guide system components, reducing overall weight and complexity. The fixed coils act as both actuation and guidance elements, streamlining the design while maintaining ease of manufacture through standard electromagnetic component fabrication.
Solution Approach 2:
The patent extracts the guidance function from separate mechanical guide components and integrates it into the magnetic field system. By taking out the guiding function from physical retainers and embedding it in the electromagnetic interaction, the design eliminates unnecessary mechanical parts, reducing weight and simplifying the overall structure while maintaining manufacturability.
4Strength
If mechanical guide systems are used to constrain movement, then the loudspeaker provides structural support, but the systems create noise through rolling or sliding contact
Solution Approach 1:
The patent replaces mechanical rolling or sliding contact systems with a magnetic field-based guidance system. The magnetic fields provide structural support and movement constraint without physical contact, eliminating the noise generated by rolling or sliding mechanisms. The movable magnet assembly is guided through magnetic field gradients that provide continuous, contactless support forces.
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 precise, silent, and compact loudspeaker operation with improved rigidity and reduced mechanical wear, while maintaining lightweight and cost-effectiveness.
Implementation Method 1
a coil (301C), configured to generate a magnetic field along a longitudinal axis (X)
Implementation Method 2
a magnet (302), located in the gap and movable inside the gap along a movement direction (M) responsive to the magnetic field generated by the coil (301C)
Data Source
AI summary
A loudspeaker, includes: a coil, configured to generate a magnetic field along a longitudinal axis; a ferromagnetic circuit including: a central core, around which the coil is wound, and an outer core located at the side of the coil and separate from the central core so as to define a gap, wherein the coil and the ferromagnetic circuit constitute a fixed working unit; a magnet, located in the gap and movable inside the gap along a movement direction responsive to the magnetic field generated by the coil; a radiator which is operatively coupled to the magnet, wherein the magnet and the radiator constitute a movable working unit; a guide system including a flexible part constituting a compliant mechanism, connected to the movable working unit and to the fixed working unit, the flexible part having a plurality of deformable joints and a plurality of rigid connecting portions, the deformable joints being interposed between the rigid connecting portions so as to guide the magnet along the movement direction by elastically deforming the flexible part.