Integrated Drive Encoder Layout for Compact Accurate Position Sensing
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Solution Overview
Problem
Existing encoder systems for drives and electric motors require large installation space, have high inertia, and low accuracy, often with separate magnetic circuits that are not spatially integrated, limiting their compactness and precision.
Innovation Solution
An encoder system with a Wiegand sensor on a stationary part and pairs of magnets on a rotatable part, combined with a magnetic field sensor and magnetic strip, where the magnets and strip are aligned to generate alternating magnetic fields, and discharge elements to shield stray fields, allowing for compact, high-accuracy position and revolution counting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic circuits and sensors of revolution counter and position encoder are spatially separated to avoid magnetic field distortion, then measurement accuracy is improved, but installation space and device diameter increase
Solution Approach 1:
The patent implements nested encoding by placing the position encoder's magnetic strip and sensors within the same radial space as the revolution counter's magnet rings. The position encoder components are nested inside the revolution counter structure, allowing both encoders to occupy the same installation space without interfering with each other's magnetic fields through proper spatial arrangement and shielding.
Solution Approach 2:
The patent transitions from spatial separation in the radial direction to separation in the axial direction. By arranging the revolution counter and position encoder at different axial positions along the shaft, the system achieves field isolation without increasing the overall radial installation space, effectively using the axial dimension to resolve the contradiction.
2Area of stationary object
If multiple encoder components are integrated in a compact arrangement, then installation space is reduced, but magnetic field interference increases
Solution Approach 1:
The patent extracts and isolates the magnetic field sources by separating the revolution counter magnets from the position encoder magnets in space. By positioning these magnetic components at different radial and axial locations, the system extracts the harmful magnetic field interference problem and resolves it through spatial distribution, allowing compact integration without field distortion.
Solution Approach 2:
The patent introduces magnetic shielding elements and non-magnetic structural components as intermediaries between the revolution counter and position encoder. These intermediary elements block and redirect magnetic field lines, preventing direct interference between the two encoder systems while maintaining their compact integrated arrangement.
3Measurement precision
If encoder system components are distributed separately for optimal performance, then measurement accuracy is improved, but assembly complexity and production difficulty increase
Solution Approach 1:
The patent merges the revolution counter and position encoder into a single integrated encoder unit with a unified structure. Both encoder types share common components such as the shaft mounting, housing, and magnetic circuit elements, allowing them to be manufactured and assembled together as one module rather than as separate distributed components, thereby simplifying production while maintaining accuracy.
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 enables a compact, high-accuracy encoder system with reduced inertia and improved assembly simplicity, capable of precise position determination and revolution counting, while shielding against interference fields.
Implementation Method 1
A revolution counter is usually specified for counting the revolutions of a shaft of a motor... the encoder system comprises a revolution counter having a Wiegand sensor
Implementation Method 2
A position encoder usually determines an angular position of the shaft... the position encoder having a magnetic field sensor... and a magnetic strip which is disposed on the rotatable part
Data Source
AI summary
Encoder system (1) for a drive, including a revolution counter having a Wiegand sensor (23) which is disposed on a stationary part (13) of the encoder system (1), and at least two pairs of magnets which in the revolving direction (5) are disposed at different positions on a rotatable part (15) of the encoder system (1), wherein the pairs of magnets comprise in each case a first magnet (35) and a second magnet (37); and a position encoder having a magnetic field sensor (43) which is disposed on the stationary part (13), and a magnetic strip (47) which is disposed on the rotatable part (15); wherein, in each pair of magnets, the first magnet (35), the magnetic strip (47) of the position encoder, and the second magnet (37) in terms of a first direction are disposed in this sequence on the rotatable part (15).