Linear Coil Position Sensing With Phase-Shifted Elements
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Solution Overview
Problem
Conventional position detection devices for moving members require a large number of coil elements, increasing installation size and weight.
Innovation Solution
A position detection device with an exciting coil and detection coils that generate voltages based on the position of a moving member, utilizing a pair of coil elements with differing output voltage phases and sub coil portions to reduce size and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a large number of coil elements are arranged side by side to detect the position of a moving member, then the detection precision is improved, but the installation size and weight increase
Solution Approach 1:
The detection coil is divided into multiple independent coil elements (first coil element, second coil element, third coil element, fourth coil element) arranged in series along the moving direction. Each coil element contributes to the overall detection capability while maintaining a compact structure, eliminating the need for a large number of coil elements arranged side by side.
Solution Approach 2:
The coil elements are arranged in a one-dimensional series configuration along the moving direction rather than being distributed in a two-dimensional array. This dimensional arrangement reduces the installation footprint and weight while maintaining detection precision through the sequential positioning of the coil elements.
2Measurement precision
If a large number of coil elements are arranged side by side to detect the position of a moving member, then the detection precision is improved, but the installation size increases
Solution Approach 1:
The detection coil is segmented into multiple coil elements arranged in series along the moving direction, creating a compact linear structure that reduces the installation area compared to a two-dimensional array of coil elements.
Solution Approach 2:
The coil elements are configured in a one-dimensional series arrangement along the moving direction rather than a two-dimensional distribution, significantly reducing the installation area while maintaining detection precision through the sequential spatial configuration.
3Weight of stationary object
If multiple coil elements with different phases are used to reduce size and weight, then the device complexity increases
Solution Approach 1:
Different coil elements are assigned specific functional roles: the first and second coil elements detect positions within the detection range, while the third and fourth coil elements detect positions outside the detection range. This local functional differentiation optimizes the detection capability while maintaining a relatively simple overall structure.
Solution Approach 2:
The multiple coil elements collectively serve both detection functions: they can detect positions within the detection range and positions outside the detection range. This multi-functionality is achieved through the series arrangement where different subsets of coil elements are activated based on the moving member's position, reducing the need for separate detection systems.
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
The device achieves a reduction in size and weight while accurately detecting the position of a moving member.
Implementation Method 1
a detection coil that outputs a voltage corresponding to a position of a detection target portion moving with the moving member by means of a magnetic field generated by the exciting coil
Data Source
AI summary
A position detection device detects a position of a moving member moving backward and forward in a predetermined moving direction. The position detection device includes an exciting coil disposed along the moving member and extending in the moving direction, a detection coil that outputs a voltage corresponding to a position of a detection target portion moving with the moving member by means of a magnetic field generated by the exciting coil within a predetermined detection range in the moving direction, and a calculation unit that calculates the position of the moving member by the output voltage of the detection coil. The detection coil includes a pair of coil elements whose output voltage changes according to the position of the moving member, and phases of the output voltages of the pair of coil elements during movement of the moving member within the detection range differ from each other.