Position Detection With Offset Coils for Compact Linear Scales
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Solution Overview
Problem
Conventional electromagnetic induction linear scales require a large coil array to cover the entire movement range of a magnetic member, leading to a bulky position detection device.
Innovation Solution
A position detection device with an exciting coil extending along the moving member and detection coils arranged perpendicular to it, where detection ranges are offset, allowing for compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a coil array is arranged over the entire movement range of the magnetic member, then position detection coverage is improved, but the size of the coil array increases
Solution Approach 1:
The detection system is divided into multiple detection coils arranged side by side in a direction perpendicular to the exciting coil's extending direction. Each detection coil covers a specific detection range, and the ranges are offset along the moving direction to achieve continuous coverage without requiring a single large coil array.
Solution Approach 2:
Instead of extending the coil array along the moving direction (one-dimensional extension), the patent arranges multiple detection coils in a direction perpendicular to the moving direction (transverse arrangement). This dimensional change allows the system to cover the entire movement range through offset detection ranges while reducing the overall device size.
2Volume of stationary object
If multiple detection coils are arranged side by side with offset detection ranges, then device size is reduced, but detection range coverage must be maintained
Solution Approach 1:
The detection function is segmented across multiple detection coils, each responsible for a specific detection range. The detection ranges are offset along the moving direction so that together they cover the entire movement range of the moving member, eliminating the need for a single large coil array.
Solution Approach 2:
Multiple detection coils work together to provide universal detection coverage across the entire movement range. Each coil contributes to the overall detection system, and their combined offset ranges ensure complete coverage while maintaining a compact device structure.
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 reduced size while maintaining accurate position detection over the entire movement range.
Implementation Method 1
an exciting coil arranged to extend in the moving direction along the moving member
Implementation Method 2
a detection coil that, by an action of a magnetic field generated by the exciting coil, can detect a position
Data Source
AI summary
A position detection device configured to detect a position of a moving member that moves back and forth in a predetermined moving direction is provided with an exciting coil arranged to extend in the moving direction along the moving member, and a detection coil that, by an action of a magnetic field generated by the exciting coil, can detect a position, in the moving direction, of a detection object portion provided on the moving member within a predetermined detection range. A plurality of the detection coils are arranged side by side in a direction perpendicular to an extending direction of the exciting coil. A plurality of the detection object portions are provided at different positions in the moving direction so as to respectively correspond to the plurality of the detection coils, and the respective detection ranges of the plurality of the detection coils are offset in the moving direction of the moving member.