Bistable Electromagnetic Actuator With Composite Ring Magnets
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Solution Overview
Problem
Conventional bistable electromagnetic actuators used in surgical instruments, such as endoscopes, face challenges with high friction, brittleness of permanent magnets, and asymmetrical forces due to dimensional deviations, leading to inefficiencies and fragility, especially when miniaturized.
Innovation Solution
The use of ring permanent magnets with hard magnetic particles embedded in a plastic matrix, allowing for precise and economical production with minimal structural deviations, and a compact design with openings for coil wires to reduce friction and enhance symmetry, along with a back-iron element and stator pole shoes to optimize magnetic flux and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional ring permanent magnets are used, then strong magnetic force is achieved, but the magnets are brittle and sensitive to mechanical loads
Solution Approach 1:
The patent uses composite ring permanent magnets consisting of magnetic particles embedded in a plastic matrix. This composite structure combines the magnetic properties of the particles with the mechanical strength and flexibility of the plastic matrix, resolving the contradiction between achieving strong magnetic force and maintaining mechanical strength.
2Force
If conventional ring permanent magnets are used, then magnetic functionality is achieved, but dimensional deviations cause asymmetrical forces
Solution Approach 1:
The plastic matrix in the composite magnets provides dimensional stability and allows for more precise manufacturing. The matrix holds the magnetic particles in a fixed arrangement, reducing dimensional deviations and ensuring symmetrical force distribution in the actuator.
Solution Approach 2:
By changing the material composition to include plastic matrix with magnetic particles, the patent achieves better dimensional control and symmetry in the magnetic field generation, eliminating the asymmetrical forces caused by manufacturing variations in conventional magnets.
3Force
If tubular soft magnetic rotor is used, then magnetic engagement is achieved, but friction against the tube is high
Solution Approach 1:
The rotor is segmented into a soft magnetic tube and separate soft magnetic elements (pole pieces) positioned at specific locations. This segmentation allows the rotor to engage magnetically at discrete points rather than along the entire tubular surface, significantly reducing friction while maintaining magnetic engagement functionality.
4Volume of moving object
If conventional actuators are miniaturized, then compact size is achieved, but friction and manufacturing difficulty increase
Solution Approach 1:
The composite ring permanent magnets with plastic matrix can be manufactured using injection molding or similar processes, which are well-suited for miniaturization. This composite approach maintains manufacturing ease even at small scales, avoiding the increased difficulty associated with conventional miniaturized actuators.
Solution Approach 2:
By changing the material parameters to use composite magnets and segmented rotors, the patent enables compact actuator design without proportionally increasing manufacturing difficulty or friction, as these features scale more favorably than conventional designs.
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 solution results in a compact, efficient, and symmetrical bistable electromagnetic actuator with balanced holding and switching forces, reduced friction, and improved mechanical properties, enabling stable operation with minimal size and material waste.
Implementation Method 1
a coil for producing the electromagnetic field, wherein the rotor at least partially comprises a paramagnetic and/or ferromagnetic material and can be reversibly displaced between a first position and a second position by applying an electromagnetic field
Implementation Method 2
the stator comprises two, which can be oppositely axially poled, ring permanent magnets
Implementation Method 3
a back-iron element having two stator pole shoes
Data Source
AI summary
A bistable electromagnetic actuator including: a tube; a stator arranged outside of the tube; and a rotor mounted in the tube so as to be displaceable along the longitudinal axis, the rotor at least partially comprises one or more of a paramagnetic and a ferromagnetic material and can be reversibly displaced between a first position and a second position by applying an electromagnetic field; wherein the stator comprises two ring permanent magnets, a coil for producing the electromagnetic field, and a back-iron element having two stator pole shoes; and the two ring permanent magnets comprise hard magnetic particles that are embedded in a plastic matrix.