Self-Centering Electromagnetic Transducer with Adjustable Reluctance
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Solution Overview
Problem
Conventional linear electromagnetic transducers rely on costly and heavy return springs to maintain self-centering, which can limit device lifetime and make it impractical to adjust the spring rate, especially during operation.
Innovation Solution
The use of self-centering electromagnetic transducers with high-reluctance zones within ferromagnetic yokes and coils, where magnetic energy is stored and used to return the magnet to a neutral position, eliminating the need for return springs and allowing for adjustable spring rates through actuators that vary the width of these zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If return springs are used to maintain self-centering in electromagnetic transducers, then the magnet can be prevented from escaping the gap and the neutral position can be defined, but the device becomes costly, heavy, and has limited lifetime due to lateral forces on bearings
Solution Approach 1:
The patent removes the return spring component entirely from the electromagnetic transducer design. Instead of using a mechanical spring to provide restoring force, the invention uses the magnetic field and magnetic reluctance inherent in the transducer's core structure to achieve self-centering. The high-reluctance zone is strategically positioned to create magnetic restoring forces that eliminate the need for external mechanical springs, thereby reducing weight and cost while improving reliability.
Solution Approach 2:
The patent replaces the mechanical return spring system with an electromagnetic field-based self-centering mechanism. The magnetic field interacts with the high-reluctance zone to generate restoring forces that center the magnet without mechanical contact. This substitution eliminates lateral forces on bearings that would otherwise be caused by spring friction and contact, extending device lifetime while maintaining the self-centering function.
2Reliability
If return springs are used in electromagnetic transducers, then self-centering is achieved, but the spring rate cannot be easily changed during operation
Solution Approach 1:
The patent implements a dynamic spring rate adjustment mechanism by making the high-reluctance zone width variable. An actuator can dynamically change the width of the high-reluctance zone during operation, which directly modifies the magnetic restoring force characteristics. This allows the effective spring rate to be adjusted in real-time based on operating conditions, providing adaptability that was impossible with fixed mechanical springs.
Solution Approach 2:
The patent changes the geometric parameter of the high-reluctance zone (its width) to control the spring rate. By varying the width of the high-reluctance zone through actuator control, the magnetic circuit's reluctance changes, which directly alters the strength of the magnetic restoring force. This parameter-based control enables continuous adjustment of the spring rate without changing the physical spring component itself.
3Reliability
If return springs are used to define neutral position, then self-centering is achieved, but the device complexity and cost increase
Solution Approach 1:
The patent makes the high-reluctance zone serve multiple functions: it defines the neutral position, provides the restoring force for self-centering, and acts as a controllable element for spring rate adjustment. This multi-functional design eliminates the need for separate neutral position definition mechanisms that would be required in spring-based designs, thereby reducing overall device complexity while maintaining or enhancing functionality.
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 design reduces the weight and cost of the transducers, extends device lifetime by eliminating lateral forces on bearings, and allows for tunable spring rates for optimal performance, making them suitable for applications like Stirling coolers.
Implementation Method 1
at least one high-reluctance zone positioned within the outer yoke and/or the inner yoke
Implementation Method 2
When the magnet is displaced from a center position between the outer yoke and the inner yoke by a displacement force, magnetic energy is stored within the outer yoke and/or the inner yoke
Implementation Method 3
A linear motor converts alternating current applied to a coil into linear translation of a magnet or coil
Implementation Method 4
A linear motor converts alternating current applied to a coil into linear translation of a magnet or coil
Implementation Method 5
a linear generator converts linear translation of a magnet into alternating current in a coil
Data Source
AI summary
Self-centering electromagnetic transducers, such as linear motors and generators, are disclosed. In one embodiment, an electromagnetic transducer includes an outer yoke made of a ferromagnetic material, and a coil assembly including a plurality of loops of electrically conductive wire, wherein the coil assembly is substantially surrounded by the outer yoke. The electromagnetic transducer further includes a magnet, and an inner yoke made of ferromagnetic material. The magnet is disposed within the outer yoke such that the coil assembly surrounds the magnet. The inner yoke is disposed within the magnet, and the magnet is free to translate. The electromagnetic transducer further includes at least one high-reluctance zone positioned within the outer yoke and/or the inner yoke. In some embodiments, the electromagnetic transducer includes one or more actuators that vary a width of one or more high-reluctance zones to change a spring rate of the electromagnetic transducer.