Levered Loudspeaker Perpendicular Magnetic Force
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Solution Overview
Problem
Levered loudspeakers face challenges in minimizing magnetic crashing forces, which can restrict the design and efficiency of the device, particularly due to magnetic attraction forces acting parallel to the pivot axis, affecting the motion and profile of the acoustic diaphragm.
Innovation Solution
The implementation of a moving magnet motor with a permanent magnet and stator, where the magnetic crashing force is arranged to be substantially perpendicular to the pivot axis, and the use of a curved air gap and rotational joints to accommodate the motion of the magnet, allowing the diaphragm to pivot without interference and reducing the overall height of the loudspeaker.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a conventional moving magnet motor is used with magnetic crashing force parallel to the pivot axis, then the motor can generate sufficient driving force, but the magnetic crashing force restricts diaphragm motion and increases device height
Solution Approach 1:
The patent inverts the conventional arrangement by orienting the magnetic crashing force perpendicular to the pivot axis rather than parallel to it. This is achieved by positioning the voice coil and magnetic field such that the force acts radially outward from the pivot axis, converting a harmful axial force into a beneficial radial force that increases diaphragm excursion without restriction.
Solution Approach 2:
The patent transitions the magnetic crashing force from acting along the pivot axis (one dimension) to acting perpendicular to the pivot axis (another dimension). This dimensional change allows the force to accommodate diaphragm motion rather than restrict it, effectively using the radial dimension to enhance excursion while the axial dimension remains free for diaphragm movement.
2Stability of the object's composition
If axially stiff rotational joints are used to support the lever, then the pivot remains stable, but the joint complexity and height increase
Solution Approach 1:
The patent extracts the axial stiffness requirement from the rotational joint design by relying on the perpendicular magnetic crashing force to provide pivot stability rather than requiring the joint itself to be axially stiff. This allows the use of simpler, more compliant rotational joints that achieve stability through the force orientation rather than joint rigidity.
Solution Approach 2:
The patent changes the force orientation parameter from parallel to perpendicular relative to the pivot axis, which fundamentally alters the stability mechanism. Instead of requiring axially stiff joints to resist axial forces, the perpendicular force orientation provides stability through radial constraints, allowing simpler joint designs with fewer components and reduced height.
3Length of stationary object
If the loudspeaker is designed for low profile, then the height is reduced, but the diaphragm motion is restricted by magnetic crashing forces
Solution Approach 1:
The patent inverts the conventional force orientation to perpendicular, which eliminates the restriction on diaphragm excursion that would normally result from low-profile design. The perpendicular magnetic crashing force acts radially outward, providing the necessary drive force while allowing the diaphragm to move freely in the axial direction, thus achieving both low profile and full excursion.
Solution Approach 2:
By moving the magnetic crashing force into the radial dimension (perpendicular to pivot axis), the patent allows the axial dimension to be minimized for low profile while the radial dimension provides sufficient force for diaphragm excursion. This dimensional separation enables independent optimization of height and excursion performance.
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
This configuration reduces the need for axially stiff rotational joints, maximizes diaphragm excursion, and minimizes lateral motion, resulting in a lower profile and more efficient operation of the loudspeaker by aligning the pivot axis and connection points perpendicular to the diaphragm's displacement axis.
Implementation Method 1
a moving magnet motor can be configured to reduce magnetic crashing force in the direction parallel to the lever's pivot axis
Implementation Method 2
the stator defines a curved air gap which accommodates motion of the permanent magnet as the permanent magnet moves in an arcuate path within the air gap
Data Source
AI summary
A loudspeaker includes an acoustic diaphragm, an oscillatory force source, a lever that couples the oscillatory force source to the acoustic diaphragm, and a pivot that is coupled to the lever such that the lever pivots about a pivot axis when the oscillatory force source applies a force to the lever. The pivot includes a pair of rotational joints which are spaced apart to allow the diaphragm to pass therebetween as the lever pivots about the pivot axis.