Coil Former Film Wrapping for Precise Air-Core Inductance Tuning
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Solution Overview
Problem
Existing inductive components face challenges in achieving precise adjustment of inductance values, particularly in resonance applications, due to variations in geometric dimensions and material properties, which are exacerbated by the absence of a magnetic core in air coils.
Innovation Solution
The use of an electrically insulating film wrapped around a non-magnetic or magnetic base body to selectively adjust the diameter of the coil former, allowing for precise tuning of inductance by varying the length and thickness of the film, and the number of turns of the winding wire.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional tuning methods (pushing core in/out or compressing winding) are used, then inductance adjustment is achieved, but manufacturing precision and reliability are compromised due to mechanical deformation and variability
Solution Approach 1:
The patent applies preliminary action by pre-setting the coil former geometry with integrated positioning features (flanges, grooves, ribs) during manufacturing. The winding wire is pre-positioned using these features before final assembly, eliminating the need for complex post-manufacturing tuning mechanisms. This ensures consistent inductance values across production batches without requiring additional adjustment steps.
Solution Approach 2:
The patent extracts the tuning function from complex mechanical mechanisms and integrates it directly into the coil former structure itself. The positioning features (flanges, grooves, ribs) are built into the base body, removing the need for separate adjustment mechanisms. This simplifies the overall device while maintaining precise inductance control through geometric design alone.
2Manufacturing precision
If geometric dimensions are precisely controlled to achieve high inductance precision, then inductance accuracy improves, but manufacturing cost and complexity increase due to tighter tolerances
Solution Approach 1:
The patent applies local quality by providing enhanced positioning features (flanges, grooves, ribs) only at critical locations where the winding wire makes contact with the coil former. The majority of the coil former body maintains standard manufacturing tolerances. This localized precision approach ensures accurate inductance values where needed while keeping overall manufacturing costs and complexity manageable.
Solution Approach 2:
The patent changes geometric parameters of the coil former (adding flanges, grooves, ribs) to create self-positioning features that guide the winding wire. These structural parameter changes replace the need for tight dimensional tolerances across the entire component, allowing standard manufacturing processes to achieve the required precision through intelligent geometric design rather than costly tight tolerances.
3Reliability
If material properties variations and temperature changes occur, then inductance value stability deteriorates, but using magnetic cores to compensate increases device complexity and loss
Solution Approach 1:
The patent replaces magnetic core-based inductance adjustment with a purely geometric approach. By using precisely positioned winding wire geometry (controlled by flanges, grooves, and ribs on the coil former), the system achieves stable inductance values without magnetic cores. This eliminates magnetic core losses while maintaining reliability through geometric consistency that is less sensitive to material property variations and temperature changes.
4Loss of energy
If air-core coil design is used to eliminate magnetic core losses, then energy loss decreases, but inductance precision and stability worsen due to geometric sensitivity
Solution Approach 1:
The patent applies preliminary action by pre-configuring the air-core coil geometry with integrated positioning features during manufacturing. The flanges, grooves, and ribs are formed on the coil former before winding, ensuring that the winding wire is automatically positioned with high precision. This preliminary geometric setup compensates for the inherent geometric sensitivity of air-core coils, achieving both low energy loss and high inductance precision without magnetic cores.
Solution Approach 2:
The patent applies local quality by adding positioning features (flanges, grooves, ribs) only at specific critical locations on the air-core coil former where winding wire positioning is needed. These localized geometric enhancements provide the necessary precision for air-core operation without requiring the entire structure to meet tight tolerances, maintaining manufacturing simplicity while achieving high inductance precision and eliminating magnetic core losses.
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
Enables highly precise adjustment of inductance values in air coils, allowing for fine-tuning within specific physical limits, achieving up to 10% adjustment in 0.1% steps, thereby addressing the need for precise inductance settings in inductive components.
Implementation Method 1
The geometric dimensions strongly influence the inductance of electrical components, especially air-core coils. High-precision inductance values can only be manufactured within certain physical limits and require precise control of the geometry.
Implementation Method 2
an inductive component comprising a coil body with a wire winding
Data Source
Figure 1~2
Figure 3A~3E
AI summary
A coil body (1) for an inductive component (7) has a main body (2), around some portions of which an electrically insulating film (3) is wound. An inductive component (7) comprises the coil body (1) and a winding wire (8) wound around said body, so that the film (3) lies between the main body (2) and the winding wire (8). In a method for adjusting an inductance, the length of the film (3) is selected according to a desired value for the inductance.