Monostable Electromagnetic Actuator with Acceleration Coils
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Solution Overview
Problem
Existing electromagnetic actuating devices in motor vehicles and industrial control systems face challenges in maintaining a stable, fail-safe position without power, as they often become indeterminate after a power failure, and their bistable nature can lead to inefficient dynamic behavior and increased energy consumption.
Innovation Solution
A currentless monostable electromagnetic actuator is designed with additional coil units and energy storage means, such as springs, to ensure predictable movement and efficient operation, combining dynamic advantages with fail-safe behavior by using a second coil unit for acceleration and reset coil means to reinforce the restoring force, allowing controlled and rapid resetting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a compression spring is provided to push the armature unit away from the core unit, then the extension of the armature unit is improved, but the dynamic behavior deteriorates due to increased mass and reduced acceleration
Solution Approach 1:
The patent removes the compression spring from the system entirely, extracting the problematic component that was causing the contradiction. Instead of using a spring to provide the pushing force, the invention uses electromagnetic repulsion between like poles of permanent magnets to achieve armature extension without adding mass or reducing acceleration.
Solution Approach 2:
The patent replaces the mechanical spring system with an electromagnetic field-based system. The restoring force is generated through electromagnetic repulsion between permanent magnets rather than mechanical elastic deformation, eliminating the need for a compression spring while maintaining the desired extension functionality.
2Stability of the object's composition
If permanent magnet means are used to hold the armature unit stable at end positions, then the stability is improved, but the fail-safe behavior deteriorates because the armature unit cannot return to a defined position after power failure
Solution Approach 1:
The patent introduces asymmetry in the magnetic circuit design by providing a magnetically conductive housing that creates a preferred return path. The housing forms a magnetic flux circuit that guides the armature unit back to a specific defined position (first end position) after power failure, breaking the symmetry between the two end positions and enabling fail-safe behavior.
Solution Approach 2:
The magnetically conductive housing acts as an intermediary element that mediates the return of the armature unit to its defined position. The housing provides a magnetic flux path that facilitates the natural return of the armature to the first end position, ensuring predictable fail-safe behavior without requiring additional active components.
3Stability of the object's composition
If a return spring is provided to reset the armature unit, then the monostable behavior is improved, but the efficiency deteriorates due to the counteracting force reducing the overall actuating efficiency
Solution Approach 1:
The patent replaces the mechanical return spring system with an electromagnetic field-based restoring force. The permanent magnets and magnetically conductive housing work together to provide the restoring force that returns the armature to its defined position, eliminating the need for a return spring and avoiding the efficiency losses associated with mechanical elastic deformation.
Solution Approach 2:
The patent uses the permanent magnets to provide both the primary actuating force and the restoring force. The permanent magnets are positioned and oriented to create asymmetric magnetic flux patterns that provide sufficient restoring force for monostable behavior without requiring additional springs or excessive magnetic strength, thereby maintaining efficiency.
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 solution achieves a stable, unambiguous actuating state in the de-energized condition without adverse effects on efficiency or dynamic properties, ensuring reliable and safe operation, particularly in motor vehicle applications.
Implementation Method 1
permanent magnetic adhesion on the core unit
Implementation Method 2
stationary electromagnetic drive means in the form of a stationary core unit, which is assigned a coil unit that can be suitably energized
Implementation Method 3
a compression spring can also be provided, which pushes the armature unit in the direction of detachment from the core unit
Data Source
Figure 1~3(c)
Figure 4~6(c)
AI summary
The invention relates to an electromagnetic actuating device which is monostable in the currentless state and has an armature unit (12) which has a permanent magnetic means (16) and which can move along a movement longitudinal axis (10) between at least two actuation positions relative to stationary coil means (28, 50, 36) and in reaction to energisation thereof, which armature unit (12) has an engagement section (26) for interacting with a plunger section (22) which provides an actuation partner and which armature unit (12) can be moved from a first of the actuation positions, which is stable in the currentless state as result of an effect of the permanent magnetic means, into a second of the actuation positions counter to a restoring force of force storage means (44), in particular spring means, wherein the coil means have a first coil unit (28) which is or can be connected in order to bring about a force which acts on the armature unit and which releases the armature unit from the first actuation position, wherein the coil means have a second coil unit (36) which is provided in addition to the first coil unit and is connected or can be connected in such a way that during the movement the second coil unit applies to the armature unit a force which accelerates the armature unit, and wherein the coil means have restoring coil means (50; 28, 36) which are embodied and/or connected in such a way that when the armature unit is returned from the second actuation position into the first actuation position said restoring coil means (50; 28, 36) boost the restoring force of the force storage means.