Actuator with Segmented Coil for High Force Density
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Solution Overview
Problem
Existing actuators with electrically conductive coils have limited force density and frequency range, with high inductance issues affecting performance, especially at higher frequencies, and are restricted by small coil installation space and wire diameters.
Innovation Solution
The actuator is enhanced by subdividing the coil into multiple winding regions with different turn counts and cross-sections, allowing independent control of each region's frequency and voltage supply, and using soft-magnetic powder composite materials for guide elements to reduce volume and increase magnetic field strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single coil with uniform windings is used, then the structure is simple, but the force density is low and the frequency range is limited
Solution Approach 1:
The coil is divided into multiple winding regions (first winding region, second winding region, etc.) with different numbers of turns and different wire cross-sections. This segmentation allows each region to be optimized for different frequency ranges, thereby increasing the overall force density and expanding the usable frequency range without excessive structural complexity.
Solution Approach 2:
Different winding regions have different local properties: the first winding region has more turns with smaller wire cross-section for low-frequency optimization, while the second winding region has fewer turns with larger wire cross-section for high-frequency optimization. This local quality variation enables the single coil structure to achieve high force density across a broad frequency range.
2Force
If the coil has high inductance, then the magnetic field strength is sufficient, but the total impedance increases at higher frequencies reducing current and force
Solution Approach 1:
The coil is segmented into multiple winding regions with different inductance characteristics. The first winding region with more turns provides sufficient magnetic field strength at low frequencies, while the second winding region with fewer turns and larger wire cross-section has lower inductance, reducing total impedance at high frequencies and maintaining current flow and force generation.
Solution Approach 2:
The inductance parameter is varied across different winding regions by changing the number of turns and wire cross-section. This parameter change allows the coil to maintain appropriate impedance levels across different frequency ranges, ensuring reliable performance from low to high frequencies.
3Volume of moving object
If the coil installation space is small, then the actuator is compact, but the wire diameter must be small limiting the frequency range
Solution Approach 1:
The limited coil installation space is segmented into multiple winding regions, each optimized for different frequency ranges. The first winding region uses thinner wire for low-frequency operation, while the second winding region uses thicker wire for high-frequency operation. This segmentation allows the compact actuator to achieve a broad frequency range despite space constraints.
Solution Approach 2:
Different local wire cross-sections are used in different winding regions within the same compact space. The local quality variation (wire diameter) allows each region to operate effectively at its optimized frequency range, expanding the overall frequency versatility of the compact actuator.
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 increases force density, expands the frequency range, and achieves linear operating behavior with higher excitation forces, reducing total inductance and ohmic resistance, while allowing tuning for specific frequency ranges and improved production efficiency.
Implementation Method 1
If a current flows through the coil, a Lorentz force acts in the direction of the longitudinal axis of the coil
Implementation Method 2
the interaction of the magnetic field lines emerging from the collar-like projections of the first guide element and the second guide element or the magnetization of the magnet, which advantageously also consist of a material with high permeability, creates a further force
Data Source
Figure 1a
Figure 1b
Figure 2
AI summary
An actuator (1), having at least one electrically conductive coil (2) which has a longitudinal axis (L) and a plurality of turns, and at least one magnet (8) which is arranged at a distance from the turns of the coil (2) in the radial direction (R) in relation to the longitudinal axis (L), wherein the at least one coil (2) is at least partially covered by a central region of a first conducting element (4) on a side which is averted from the magnet (8), and the at least one magnet (8) is at least partially covered by a central region of a second conducting element (10) on a side which is averted from the turns of the at least one coil (2), wherein the first conducting element (4) projects beyond the at least one coil (2) and the second conducting element (10) projects beyond the at least one magnet (8) in the axial direction in relation to the longitudinal axis (L) and there each have collar-like projections (6, 7), is distinguished in that the at least one coil (2) has at least a first turn region (2a) and a second turn region (2b).