Inductive Position Measurement Device With Offset Receiver Tracks
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Solution Overview
Problem
Inductive position measuring devices struggle to accurately determine positions in two directions with precision and cost-effectiveness, particularly in applications requiring both angular and axial position measurements over a larger measuring path.
Innovation Solution
The design incorporates a scanning element with multiple receiver tracks and a scale element featuring graduation structures with periodic courses, where the receiver tracks are offset in a specific manner to allow for precise measurement in both directions, enabling two-dimensional position determination with phase-shifted signals to correct for errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple receiver tracks are used to measure positions in two directions, then measurement capability is improved, but device complexity increases
Solution Approach 1:
The receiver system is segmented into multiple receiver tracks (first, second, and third receiver tracks) with different offset distances from the excitation line. Each receiver track independently measures position in the second direction, enabling two-dimensional position measurement while maintaining manageable complexity through modular segmentation of the measurement function.
Solution Approach 2:
The invention transitions from one-dimensional position measurement to two-dimensional position measurement by adding receiver tracks offset in the second direction. The receiver tracks are positioned at different distances (offsets) from the excitation line in the second direction, creating a dimensional expansion that enables simultaneous measurement in both first and second directions.
2Ease of manufacture
If receiver tracks are offset by multiples of the second period length, then signal processing is simplified, but measurement precision deteriorates
Solution Approach 1:
The invention employs asymmetric offset distances for the receiver tracks relative to the excitation line. The first receiver track has a first offset distance, the second receiver track has a second offset distance, and the third receiver track has a third offset distance, where these offsets are specifically chosen to be non-multiples of the second period length. This asymmetric positioning ensures that the signals generated by the receiver tracks are not harmonically related, thereby maintaining measurement precision while allowing for effective signal processing.
3Measurement precision
If a circumferential groove is used to determine axial displacement, then axial position can be measured, but the measuring range is limited
Solution Approach 1:
Instead of using a single circumferential groove structure, the invention segments the measurement function across multiple receiver tracks (first, second, and third receiver tracks) positioned at different offset distances. Each receiver track contributes to measuring position in the second direction, and by combining the measurements from multiple tracks with different offsets, the system achieves an extended measuring range while maintaining axial displacement measurement capability.
Solution Approach 2:
The invention moves from a single-plane measurement approach to a multi-plane measurement approach by positioning receiver tracks at different offset distances in the second direction. This dimensional arrangement allows the system to measure axial displacement over an extended range by utilizing the combined information from receiver tracks at different positions, effectively expanding the measurable range beyond what a single groove could provide.
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 configuration enables precise and cost-effective measurement of positions in two directions, improving accuracy and extending the measurable path for axial offsets, while maintaining phase-shifted signals to correct for angular position errors.
Implementation Method 1
When a time-varying electrical excitation current is applied to the excitation lines, signals dependent on the angular position are generated in the receiver coils during the relative rotation between the rotor and stator
Data Source
Figure 1~2
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AI summary
The invention relates to an inductive position measuring device comprising a scanning element (1) and a scale element (2). The position measuring device allows the positions of the scanning element (1) relative to the scale element (2) to be determined in a first direction (x) and in a second direction (z). The scale element (2) comprises graduation structures (2.1) arranged sequentially along the first direction (x), wherein the graduation structures (2.1) have a periodic pattern along a second direction (z) with a second period length (Dz). The scanning element (1) comprises a first receiver track (1.1), a second receiver track (1.2), and a third receiver track (1.3), as well as an excitation line (1.4, 1.5, 1.6). Each of the three receiver tracks (1.1, 1.2, 1.3) has two receiver conductors (1.11, 1.12, 1.21, 1.22, 1.31, 1.32). The receiver conductors (1.11, 1.12, 1.21, 1.22, 1.31, 1.32) exhibit a periodic profile along the first direction (x) with a first period length (Px), wherein the receiver tracks (1.1, 1.2, 1.3) are arranged offset from each other in the second direction (z).