Stacked Inductive Rotary Encoder Tracks for Compact Design
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Solution Overview
Problem
Inductive detection type rotary encoders with multiple tracks require a larger outer diameter due to concentric arrangement, which complicates their application in compact devices like hand tools, and suffer from crosstalk issues affecting measurement accuracy.
Innovation Solution
The design incorporates a stator and rotor with annularly formed transmission and reception wirings and magnetic flux couplers, stacked via insulative layers, allowing for reduced size and independent formation of tracks with different pitches to minimize crosstalk and enhance measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple tracks are concentrically arranged in the rotary encoder, then the outer diameter increases, but the measurement capability for absolute position is improved
Solution Approach 1:
The patent transitions from a planar concentric arrangement to a three-dimensional stacked arrangement. Multiple tracks are arranged vertically along the axial direction rather than radially in the same plane. This dimensional change allows multiple tracks to coexist without increasing the outer diameter, as they occupy different positions in the axial dimension instead of requiring increasing radial space.
Solution Approach 2:
The patent implements a nested structure where multiple track components (transmission wirings, reception wirings, magnetic flux couplers) are stacked one above another along the axial direction. Each track is effectively nested within the same radial footprint, with components of different tracks positioned at different axial levels, similar to nested dolls occupying the same space at different depths.
2Reliability
If multiple tracks are arranged in the rotary encoder, then the outer diameter increases, but the signal tracking capability is improved
Solution Approach 1:
The patent uses the axial dimension to separate multiple tracks that would otherwise require radial separation. By stacking transmission wirings, reception wirings, and magnetic flux couplers at different axial positions, the design achieves multi-track functionality without increasing the radial outer diameter, thereby maintaining compactness while improving signal tracking reliability.
Solution Approach 2:
The patent divides the encoder into multiple independent track segments stacked axially. Each track consists of its own transmission wiring, reception wiring, and magnetic flux coupler assembly, allowing independent operation and signal processing. This segmentation enables reliable multi-track signaling within a compact radial footprint.
3Measurement precision
If tracks are arranged with different pitches in the same plane, then measurement accuracy is improved, but the structure becomes more complex
Solution Approach 1:
The patent resolves the complexity issue by stacking tracks with different pitches in the axial direction rather than arranging them concentrically in the same plane. Each axial level can accommodate a track with a specific pitch optimized for different measurement resolutions, eliminating the need for complex overlapping planar arrangements while maintaining the ability to achieve high measurement accuracy through multiple pitch values.
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 reduces the outer diameter of the rotary encoder, simplifies the structure, and improves measurement accuracy by reducing crosstalk and allowing for higher sensitivity, particularly with a shorter pitch track.
Implementation Method 1
an inductive detection type rotary encoder for measuring a rotation angle of an object by use of magnetic flux coupling between wirings provided in a rotor and a stator
Data Source
AI summary
A first reception wiring and a first magnetic flux coupler form a first track having a shape periodically changing in a rotation direction of the rotor at a first pitch. A second reception wiring and a second magnetic flux coupler form a second track having a shape periodically changing in a rotation direction of the rotor at a second pitch. The first reception wiring and the second reception wiring are stacked via a first insulative layer in a direction in which a rotation shaft extends. The first magnetic flux coupler and the second magnetic flux coupler are stacked via a second insulative layer in a direction in which the rotation shaft extends.