Inductive Encoder Dummy Pattern for Magnetic Field Disturbance
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Solution Overview
Problem
Inductive detection encoders face measurement errors due to disturbances in the magnetic field generated by leading wiring units, which affect the reception signal and precision, especially in rotary and linear encoders.
Innovation Solution
The implementation of a specific pattern and a dummy pattern in the transmitting and receiving coils, with the dummy pattern positioned at specific phase relationships and intervals to cancel out the effects of the leading wiring lines, ensuring high precision measurements by balancing the magnetic field patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If leading wiring units are provided in the transmitting and receiving coils to supply power and draw signals, then the encoder can operate, but measurement errors occur due to magnetic field disturbance from the leading wiring units
Solution Approach 1:
The patent applies the 'Blessing in disguise' principle by introducing dummy patterns that replicate the harmful magnetic field effects of leading wiring units. These dummy patterns generate compensating disturbances that cancel out the actual wiring unit disturbances, converting the harmful magnetic field interference into a beneficial cancellation effect. The dummy patterns are positioned at specific intervals (nλ) to create opposite-phase magnetic field disturbances that neutralize the measurement errors caused by the leading wiring units.
Solution Approach 2:
The patent implements 'Preliminary anti-action' by pre-positioning dummy patterns in predetermined locations before the actual measurement process. These dummy patterns are designed to generate magnetic field disturbances that are equal in magnitude but opposite in phase to the disturbances caused by leading wiring units. By establishing this counteracting magnetic field pattern in advance, the system proactively neutralizes the harmful effects of wiring unit interference before they can affect measurement accuracy.
2Measurement precision
If dummy patterns are added to cancel leading wiring line effects, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent applies the 'Copying' principle by creating dummy patterns that are exact replicas of the leading wiring unit patterns. These dummy patterns are positioned at specific intervals (nλ, where n is an integer) to replicate the magnetic field disturbance characteristics of the actual wiring units. By copying the harmful pattern and positioning it strategically, the system creates a predictable and calculable counteracting effect that cancels the measurement errors without requiring complex additional components.
3Measurement precision
If the transmitting coil and receiving coil are arranged with specific patterns to improve uniformity, then signal quality improves, but manufacturing complexity increases
Solution Approach 1:
The patent implements 'Parameter changes' by systematically varying the positioning parameters of the dummy patterns based on the wavelength λ of the magnetic field. The dummy patterns are positioned at intervals of nλ (where n is an integer) relative to the leading wiring units, creating a parameter-based solution that can be adapted to different operating frequencies and wavelengths. This approach allows the same basic pattern design to be used across different applications by simply adjusting the spacing parameter, thereby improving signal quality without proportionally increasing manufacturing complexity.
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 significantly reduces measurement errors and improves signal-to-noise ratios, allowing for precise position and size measurements in various encoders, including rotary and linear types, while minimizing the number of components and avoiding additional layers.
Implementation Method 1
a transmitting coil formed in the first member; a magnetic flux coupled body which is formed in the second member, comprising a magnetic flux coupling coil forming a track... whereby a magnetic field generated by the transmitting coil is coupled to the magnetic flux coupling coil and a current induced in the magnetic flux coupling coil
Implementation Method 2
a receiving coil formed in the first member and having receiving loops periodically formed along the measurement direction... which generates a magnetic field which is periodically changed in the measurement direction
Data Source
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AI summary
An inductive detection encoder according to the present invention includes: first and second members which are oppositely disposed so as to relatively move in a measurement direction; a transmitting coil formed in the first member; a magnetic flux coupled body which is formed in the second member and coupled with a magnetic field generated by the transmitting coil; and a receiving coil formed in the first member and having receiving loops. At least one of the transmitting coil and the receiving coil has a specific pattern that impairs the uniformity and periodicity of a pattern; and a dummy pattern formed in a position corresponding to a specific phase relationship of a cycle generated by the track with respect to the specific pattern.