Rotary Sensor Shield for Magnetic Interference
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Solution Overview
Problem
Existing rotary sensors in heavy machines face inaccuracies due to magnetic hysteresis and interference from external ferrous components, leading to complex and cumbersome mounting processes.
Innovation Solution
A rotary sensor assembly featuring a sensor housing, a sensor shield made of highly permeable material, and a sensor with multiple magneto-resistive sensor elements arranged along the inner circumference of a printed circuit board, which is electrically connected to an ASIC for enhanced position detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnetic sensor and permanent magnet are used to detect rotary shaft position, then position detection capability is achieved, but measurement precision deteriorates due to magnetic field interference from ferrous components
Solution Approach 1:
A non-magnetic shield structure is introduced as an intermediary between the magnetic sensor and external ferrous components. This shield blocks magnetic field interference from reaching the sensor, thereby protecting the measurement system without affecting the detection of the rotary shaft's magnetic field signals.
Solution Approach 2:
The sensor housing is designed with differentiated material properties: the main housing may be made of magnetic or ferrous material for structural purposes, while the shield portion is specifically made of non-magnetic material to protect the sensor. This local differentiation allows the system to maintain overall structural integrity while creating a protected zone around the sensitive magnetic sensor.
2Reliability
If multiple ferrous components are present in heavy machines, then structural strength and functionality are improved, but magnetic sensor reliability deteriorates due to field interference
Solution Approach 1:
The non-magnetic shield acts as a mediator that selectively blocks harmful magnetic fields from ferrous components while allowing the desired magnetic field signals from the rotary shaft to reach the sensor. This enables reliable operation in environments with multiple ferrous components.
Solution Approach 2:
The shield extracts or isolates the magnetic sensor from the interfering magnetic environment created by ferrous components. By physically separating the sensor from the source of interference through the protective shield, the system maintains reliability despite the presence of necessary ferrous structural components.
3Measurement precision
If a complex mounting arrangement is used to accommodate magnetic interference issues, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The shield is integrated into the sensor housing structure, combining the protective function with the mounting structure. This merging eliminates the need for separate complex mounting arrangements to protect against interference, as the housing itself provides the necessary protection while maintaining simple installation procedures.
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 accurate and reliable detection of rotary shaft position changes, minimizes interference from ferrous components, and simplifies the mounting process due to its unitary structure and adaptable design.
Implementation Method 1
The plurality of sensor elements comprises magneto-resistive elements
Implementation Method 2
the sensor shield is composed of a highly permeable material
Data Source
AI summary
A sensor assembly for a rotary sensor is provided. The sensor assembly comprises a sensor housing, a sensor shield, and a sensor. The sensor housing defines a cavity. The sensor shield is disposed within the cavity of the sensor housing and defines a slot along a length of the sensor shield. The sensor shield is composed of a highly permeable material. The sensor is disposed within the cavity and at least a portion of the sensor is positioned within the slot of the sensor shield. The sensor comprises a printed circuit board having a plurality of sensor elements disposed along an inner circumference of the printed circuit board in a radially outward direction, and each sensor element is positioned at an equal distance from each other.