Actuator Yoke Recess for Integrated Sensor Shielding
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Solution Overview
Problem
Existing electric positioning assemblies face challenges in compact design and sensitivity to magnetic fields, with external sensors adding size and requiring additional shielding, while internal sensors compromise actuator force or torque, and built-in detection methods are complex or unsuitable for certain applications.
Innovation Solution
A compact positioning assembly with a position sensor integrated inside the actuator, featuring a stator with coils and a yoke with a recessed permanent magnet and magneto-sensitive probe oriented perpendicularly to the main axis, ensuring insensitivity to the magnetic field and utilizing the actuator's symmetry for magnetic shielding without additional parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a position sensor is attached externally to the actuator, then the sensor can detect position reliably, but the overall dimensions of the actuator increase and additional shielding is required
Solution Approach 1:
The sensor assembly is merged with the actuator by integrating the sensor housing with the actuator yoke structure. The sensor housing forms part of the actuator assembly, eliminating the need for separate external mounting and reducing overall dimensions while maintaining sensor functionality.
Solution Approach 2:
The magnetic field that would normally interfere with the sensor is converted into a beneficial shielding effect. The ferromagnetic material in the yoke, which could potentially distort the magnetic field, is instead utilized to provide magnetic shielding that protects the sensor from external magnetic interference, eliminating the need for additional shielding components.
2Object-affected harmful factors
If the sensor is positioned on top of the actuator, then magnetic field interference is reduced, but the overall dimensions increase and additional ferromagnetic shielding parts are required
Solution Approach 1:
The yoke structure serves multiple functions: it provides mechanical support for the sensor, forms part of the actuator assembly, and simultaneously provides magnetic shielding. This multi-functionality eliminates the need for separate shielding components while maintaining protection against magnetic field interference.
Solution Approach 2:
The actuator's own ferromagnetic yoke structure provides the magnetic shielding function that would otherwise require additional components. The existing material in the actuator is utilized to protect the sensor, making the system self-sufficient and eliminating additional parts.
3Volume of moving object
If an air gap is created in the magnetic circuit for sensor integration, then the sensor fits inside the actuator, but the force or torque produced by the actuator is reduced
Solution Approach 1:
The air gap is localized to a specific region where the sensor is integrated, rather than being distributed throughout the magnetic circuit. This minimizes the impact on overall magnetic flux and force production by confining the reluctance increase to a small local area.
Solution Approach 2:
The air gap dimension is optimized to be just sufficient for sensor integration while minimizing the impact on magnetic circuit performance. The gap is made as small as possible while still accommodating the sensor, balancing the need for sensor integration with the need to maintain actuator force.
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 provides a compact, symmetric positioning system that maintains actuator performance by eliminating sensitivity to the magnetic field, allowing for precise position detection without increasing overall dimensions or requiring external shielding, suitable for both linear and rotary actuators.
Implementation Method 1
at least one magneto-sensitive probe fixed relative to the magnet and able to measure the amplitude or direction of the magnetic field emitted by the magnet
Implementation Method 2
a stator formed of at least one ferromagnetic stator having at least one electric power supply coil, and a yoke able to move relative to the stator assembly
Data Source
AI summary
A positioning assembly includes a position sensor and a magnetic actuator, the actuator including a stator assembly formed of at least one ferromagnetic stator bearing at least one electric power supply coil and a yoke able to move relative to the stator assembly, the actuator having a geometry that is of revolution or periodic about an axis referred to as the main axis passing through the yoke, the sensor having at least one permanent magnet secured to the yoke and at least one magneto-sensitive probe that is fixed in relation to the magnet and able to measure the amplitude or direction of the magnetic field emitted by the magnet. The yoke has an interior recess including the main axis of the actuator, and the magnet is positioned inside the recess and secured to the yoke.