Position detection device
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Solution Overview
Problem
Conventional electromagnetic induction linear scales require a large number of coil elements, leading to increased size and weight, which is undesirable for certain applications.
Innovation Solution
A position detection device with an exciting coil and detection coils that generate a voltage based on magnetic field intensity differences, allowing for position calculation using a calculation unit, reducing the need for extensive coil arrays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a large number of coil elements are lined up over the entire movement range, then position detection accuracy is improved, but device size and weight increase
Solution Approach 1:
The patent divides the detection range into multiple detection ranges, with each detection coil responsible for a specific segment. This segmentation allows the system to achieve full-range position detection accuracy while keeping each individual coil compact and lightweight, avoiding the need for one large coil array covering the entire movement range.
Solution Approach 2:
The patent transitions from a one-dimensional linear arrangement of coil elements to a two-dimensional configuration where multiple detection coils are arranged in relation to a rotating detection object. This dimensional change enables the system to achieve comprehensive position detection coverage without requiring a proportional increase in the number of coil elements along the movement axis.
2Measurement precision
If a large number of coil elements are lined up over the entire movement range, then position detection accuracy is improved, but installation size increases
Solution Approach 1:
The patent divides the detection range into multiple detection ranges, with each detection coil responsible for a specific segment. This segmentation allows the system to achieve full-range position detection accuracy while keeping each individual coil compact, thereby reducing the overall installation footprint.
Solution Approach 2:
The patent transitions from a one-dimensional linear arrangement to a two-dimensional configuration where multiple detection coils are arranged in relation to a rotating detection object. This dimensional change enables comprehensive detection coverage with a more compact installation size.
3Adaptability or versatility
If a large number of coil elements are used, then detection coverage is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple detection coils with a rotating detection object that has conductive portions arranged at specific positions. This merging creates an integrated system where the rotation of the detection object sequentially brings different conductive portions into alignment with the detection coils, enabling multi-range detection coverage without requiring separate coil arrays for each range.
Solution Approach 2:
The patent utilizes the periodic rotation of the detection object to sequentially activate different detection ranges. As the detection object rotates, its conductive portions periodically align with the detection coils, creating a time-multiplexed detection system that achieves comprehensive coverage while using a limited number of physical coil elements.
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 solution achieves a reduction in size and weight of the position detection device while maintaining accurate position detection capabilities.
Implementation Method 1
an exciting coil (300) arranged to extend in the axial direction of the rack shaft (13)
Implementation Method 2
a detection coil (31-34) that, by a magnetic field generated by the exciting coil (300), outputs a voltage corresponding to a position of a detection object portion (21, 22)
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, a detection coil that, by a magnetic field generated by the exciting coil, outputs a voltage corresponding to a position of a detection object portion moving together with the moving member within a predetermined detection range in the moving direction, and a calculation unit that determines the position of the moving member by calculation based on an output voltage of the detection coil. The detection object portion has a predetermined length in the moving direction, and a voltage is generated in the detection coil due to a difference in magnetic field intensity between a portion corresponding to the detection object portion and a portion not corresponding to the detection object portion. During movement of the moving member in one direction, the output voltage of the detection coil changes sinusoidally over the entire period between when the detection coil and at least a portion of the detection object portion begin to line up in a direction perpendicular to the moving direction and when the entire detection object portion becomes out of alignment with the detection coil in the direction perpendicular to the moving direction.