Coil Form Shaping for Miniaturized Electrical Heaters
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Solution Overview
Problem
Miniaturization of electrical heating devices for low-voltage applications poses challenges due to the need for large cross-section connecting wires, which can make the coil form breakable during press contacting, especially in compact designs.
Innovation Solution
The method involves shaping the coil form with targeted compacting within the tubular metal jacket, creating openings that allow for press contacting and deformation, enabling larger cross-sectional surfaces for connecting wires and reducing the risk of breakage by altering the ratio and position of the coil form's axes during compacting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the heating device is miniaturized for low-voltage applications, then the installation space is reduced, but the connecting wires require large cross sections which make the coil form breakable during press contacting
Solution Approach 1:
The coil form is pre-shaped with an oval cross-section before assembly, creating larger openings that can accommodate large cross-section connecting wires without requiring thick coil form walls, thus preventing breakage during press contacting while maintaining miniaturized dimensions
Solution Approach 2:
The coil form uses an asymmetric oval cross-section instead of a circular one, strategically positioning larger openings to accommodate the connecting wires while optimizing the distribution of material thickness to prevent breakage in critical areas during press contacting
2Reliability
If press contacting is used to create robust electrical contact, then the contact reliability is improved, but the coil form with thin walls becomes easily breakable
Solution Approach 1:
The coil form is pre-formed with an oval cross-section that creates larger openings before assembly, allowing connecting wires to be positioned optimally within the opening. This preliminary shaping ensures that during press contacting, the contact force is distributed more favorably, achieving reliable electrical contact without concentrating stress that would cause the thin-walled coil form to break
3Temperature
If the coil form cross-section is optimized for temperature profile, then the heating performance is improved, but the available surface area for openings is limited
Solution Approach 1:
The coil form employs an asymmetric oval cross-section where the shape is optimized to maintain the desired temperature profile on the heating surface while simultaneously providing strategically positioned and sized openings. The asymmetric geometry allows one dimension to be optimized for thermal performance while the other dimension accommodates the connecting wires with sufficient cross-sectional area
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 approach allows for the reliable manufacturing of miniaturized electrical heating devices with improved durability and reduced waste, accommodating larger connecting wires while maintaining the desired temperature profile.
Implementation Method 1
the compacting deforms the coil form so that the ratio between the length of the main axis and the length of the secondary axis and/or a change of the position of the main axis and secondary axis relative to each other is produced
Implementation Method 2
the heating effect is achieved by the use of a heating wire or resistive wire
Implementation Method 3
a tubular metal jacket that is filled with a powder or granulate with good heat-conducting, but electrically insulating properties, particularly, magnesium oxide
Data Source
AI summary
A method for manufacturing an electrical heating device includes the steps of providing a coil form with a longitudinal axis, winding an electrical heating element on the coil form along the longitudinal axis and inserting one end section of the electrical heating element and a connecting wire into the opening passing through the coil form, inserting the coil form with an electrical heating element wound on it into an opening passing through the coil form parallel to the longitudinal axis into the interior of a tubular metal jacket, filling the tubular metal jacket with an electrically insulating, heat-conductive powder and compacting the tubular metal jacket with coil form inserted therein and filled with the electrically insulating, heat-conductive powder, wherein, by means of the compaction, the coil form is deformed to change the ratio between the length of the main axis and the length of the secondary axis.