Sensor Actuating Element Using Segmented Soft-Magnetic Foil Stack
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Solution Overview
Problem
Existing sensors with ferrous plastic films as soft-magnetic actuating elements face limitations in achieving sufficient pressing forces due to their stiffness, requiring increased magnetic forces for actuation, which can be inefficient.
Innovation Solution
A stack of thin, flexible soft-magnetic foil bodies is used, allowing for cumulative actuation forces with low magnetic attraction, where each foil body is movable relative to shear forces, enhancing flexibility and actuation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a ferrous plastic film is used as a soft-magnetic actuating element, then the sensor can be actuated, but only comparatively small pressing forces can be realized
Solution Approach 1:
The actuating element is divided into multiple thin foil bodies stacked together. Each foil body can deflect independently under magnetic force, and their combined pressing forces add up to generate sufficiently large contact pressure forces while maintaining flexibility that a single thick film cannot achieve
Solution Approach 2:
The actuating element uses a composite structure of multiple soft-magnetic foil bodies stacked together. This composite configuration combines the magnetic properties of soft-magnetic materials with the flexibility of thin foils, achieving both adequate pressing force and necessary flexibility for sensor actuation
2Force
If the thickness of the ferrous plastic film is increased to enable greater pressing forces, then the pressing force increases, but the film becomes comparatively stiff
Solution Approach 1:
Instead of using a single thick film, the solution segments the total thickness into multiple thin foil bodies. Each thin foil maintains high flexibility and can deflect easily under magnetic force, while the stack of multiple foils generates sufficient pressing force through cumulative effect
Solution Approach 2:
The foil bodies are arranged to be movable relative to one another in the shearing direction, allowing dynamic deflection and flexibility. This movable arrangement enables the stack to adapt to magnetic forces while maintaining flexibility, unlike a rigid thick film
3Force
If sheet metal strip is used instead of ferrous plastic film to increase pressing force, then pressing force increases, but the material becomes comparatively stiff requiring increased magnetic forces
Solution Approach 1:
The solution uses thin soft-magnetic foil bodies instead of stiff sheet metal. These thin foils are flexible and can be easily deflected by magnetic forces, reducing the magnetic force requirement while still generating adequate pressing forces through the stacked configuration
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 enables reliable sensor actuation with relatively small magnetic forces, achieving comparable actuation forces to thicker films while maintaining flexibility, thus overcoming the limitations of traditional ferrous plastic films.
Implementation Method 1
The sensor can be actuated without contact by means of magnetic forces, for example with the aid of a permanent magnet which can be positioned along the sensor on a side of the sensor which is remote from the actuating element. The actuating element is attracted to the respective position of the permanent magnet
Implementation Method 2
The individual foil bodies are comparatively thin, e.g. B. they have a thickness of less than 0.1 mm. As a result, the film bodies are comparatively flexible and can be precisely locally elastically bent even with small magnetic forces
Data Source
Figure 1~3
AI summary
The sensor (1) has carrier foils (2, 3) arranged at a distance from each other, and comprising electrodes (4, 5). A soft magnetic actuating element (8) extends along one of the carrier foils, and is arranged on the carrier foils. The actuating element has a stack (9) of soft magnetic foil bodies (10, 11, 12) that are flexibly and movably arranged relative to each other in a clipping direction. The soft magnetic foil bodies consist of ferrous magnetic material or iron sheet metal. The soft-magnetic foil bodies are congruently arranged and/or exhibit same thicknesses.