Magnetic Resolver With Offset Rotor Profile For Assembly Error Tolerance
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Solution Overview
Problem
Conventional magnetic resolvers face challenges in assembly complexity and limited coil winding increases, which hinder the enhancement of rotation angle detection resolution and accuracy due to lack of specific configurations for film-shaped coils and protruding poles.
Innovation Solution
A magnetic resolver design featuring a columnar core with a sine-function radius variation and offset middle position, allowing for easier assembly and increased coil windings without thickness increase, using substrates with through holes for assembly and electrical connections, and separate substrates for each phase to improve versatility and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If film-shaped coils are used instead of wire-wound coils, then the resolver body thickness is reduced and assembly is simplified, but the number of coil windings cannot be easily increased
Solution Approach 1:
Multiple coil patterns are formed on separate substrates that are stacked and nested together. Each substrate carries a coil pattern, and by stacking multiple substrates with their coils connected in series, the effective number of windings is increased while maintaining a compact thickness. This is achieved by forming through-holes in the substrates to pass magnetic flux and connecting coil terminals between layers.
Solution Approach 2:
The coil structure transitions from a single-plane wire winding to a multi-layer stacked configuration. By utilizing the vertical stacking dimension, multiple coil patterns are arranged in layers, allowing the number of windings to be increased by adding layers rather than increasing the radial dimension, thus maintaining thin profile while increasing effective windings.
2Measurement precision
If the middle position of the profile-varying region is aligned with the central axis of the columnar core, then the magnetic resistance variation range is maximized, but assembly errors cause waveform disturbance at certain rotational positions
Solution Approach 1:
The middle position of the profile-varying region is deliberately offset from the central axis of the columnar core by a specific distance (5-15% of the core radius). This asymmetric positioning ensures that the minimum radius part of the rotor never aligns perfectly with the core periphery, preventing waveform distortion caused by assembly errors while maintaining sufficient magnetic coupling for accurate detection.
Solution Approach 2:
The offset positioning is designed in advance to preemptively prevent the harmful alignment between the rotor minimum radius part and core periphery. By creating this predetermined offset, the system eliminates the possibility of waveform disturbance before it can occur during operation, compensating for potential assembly tolerances.
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 design enhances the resolution and accuracy of rotation angle detection by maintaining a stable magnetic resistance variation and minimizing assembly errors, while allowing for robust and flexible coil configurations.
Implementation Method 1
a magnetic resolver which includes: a base plate on which core portions are formed; a rotor facing the top faces of the cores from above with a space therebetween; and a coil substrate on which coil portions are formed, each of the coil portions surrounding a corresponding one of the cores
Implementation Method 2
detects a rotation angle of the rotor core by using the fact that the inductance of a coil varies with the rotation angle of the rotor core
Data Source
Figure 1
Figure 2~3
Figure 4~5B
AI summary
A magnetic resolver includes: a plurality of columnar cores disposed on an annular plate; a coil portion disposed around each of the columnar cores; and an annular rotor having a sinusoidal profile that rotates in a plane parallel to the top faces of the columnar cores around a rotation axis that passes through the center of the annular plate. The coil portion may be formed of a patterned coil formed on an annular substrate that has a plurality of through holes made therein through which the plurality of cores are passed, the patterned coil being formed around the through hole.