Rectangular Coil Winding Body for Stable Current Sensor Winding
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Solution Overview
Problem
Current coil elements for current sensing devices face challenges with wire tension variations due to non-circular winding contours, leading to reduced winding speed and quality, especially in constrained spaces with manufacturing imperfections like steps and flash/burrs.
Innovation Solution
A coil element design featuring a winding body with a substantially rectangular cross-section and specific curvature radii at corners and inner regions, optimizing wire tension and contact to minimize stress and maximize winding speed and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a rectangular winding contour is used to maximize space utilization, then space efficiency is improved, but wire tension variations increase causing reduced winding quality
Solution Approach 1:
The winding body implements different curvature radii at different locations: larger radius Rc at corners and smaller radius Ra at straight sections. This local differentiation allows the corners to smoothly guide the wire (reducing tension peaks) while maintaining straight sections for compactness, thus resolving the contradiction between space utilization and winding quality
Solution Approach 2:
The invention introduces curved transition regions with specific radius ratios (Rc/Ra between 1.2-2.0) at the corners of the rectangular winding body. These curved regions replace sharp corners, enabling smoother wire path transitions and reducing tension variations during winding, thereby improving winding quality while maintaining the compact rectangular overall shape
2Manufacturing precision
If corner rounding is increased to smooth wire tension, then winding quality is improved, but available space is significantly reduced
Solution Approach 1:
The patent applies different curvature radii at different locations: larger radius Rc at corners for smooth wire guidance and smaller radius Ra at straight sections for space efficiency. This localized approach allows corner rounding to improve winding quality without excessively reducing the available winding space
Solution Approach 2:
The invention optimizes the ratio between corner radius Rc and straight section radius Ra (Rc/Ra between 1.2-2.0) to achieve the best balance between smoothing wire tension at corners and maintaining sufficient winding space. This parameter optimization resolves the contradiction by finding the optimal compromise point
3Productivity
If injection point is placed on the winding body to optimize material flow, then manufacturing efficiency is improved, but molding imperfections increase
Solution Approach 1:
The patent places the injection point specifically at the center of one of the straight sections of the rectangular winding body, away from the corner regions. This localized placement allows the injection point to be on the winding body (improving material flow) while avoiding the creation of imperfections in the critical corner regions where wire tension is most sensitive
4Stability of the object's composition
If wire tension is increased during winding to prevent loose positioning, then winding stability is improved, but wire breaking risk increases
Solution Approach 1:
The curved transition regions with optimized radius ratios (Rc/Ra between 1.2-2.0) at the corners create smooth wire path transitions that reduce tension peaks. This allows the wire to be wound with moderate, constant tension, preventing both loose positioning and wire breaking by eliminating sharp tension variations at corners
Data Source
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AI summary
The present invention relates to 1 coil element (30) for a current sensing device, the coil element comprising: a winding body (10); and a length of wire (80); wherein the winding body has an outer surface around an axis of the winding body; wherein at least a portion of the length of wire is wound multiple times around the outer surface of the winding body in a generally circumferential direction with respect to the axis of the winding body; wherein a cross section of the outer surface perpendicular to the axis of the winding body has a substantially rectangular shape with two first sides opposite to one another and two second sides opposite to one another, and wherein a first axis of the cross section is equally spaced from the two first sides and has a dimension, a, and a second axis of the cross section perpendicular to the first axis of the cross section is equally spaced from the two second sides and has a dimension, b; wherein the cross section at corner regions (a2, a2', b2, b2') of the substantially rectangular shape has a first radius or range of first radii, rc; wherein the cross section at first inner regions (a1, a1') of the first sides adjacent to the corner regions has a second radius or range of second radii, ra; wherein the cross section at second inner regions (b1) of the second sides adjacent to the corner regions has a third radius or range of third radii, rb; wherein the cross section at middle regions (a0) of the first sides between the first inner regions of the first sides has a fourth radius or fourth range of radii, rao; wherein a ≥ b; wherein rc < ra < ∞; wherein rc < rb < ∞; wherein ra < ra0; and wherein rb < ra0; and wherein a dimension of the cross section parallel to the first axis from a second inner region of a second side to a second inner region of the opposite second side is less than the dimension, a; and wherein a dimension of the cross section parallel to the second axis from a first inner region of a first side to a first inner region of the opposite first side is less than the dimension, b.