Contactless Force Sensor Using Magnetic Field Detection
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Solution Overview
Problem
Current force measurement technologies, particularly for bending forces on rotating shafts, require mounting or pre-processing, which can interfere with the shaft's movement and are limited in environmental adaptability and accessibility.
Innovation Solution
A contactless force measurement sensor using a magnetic principle with a magnetic field generating unit and detector, capable of measuring forces on ferromagnetic objects without physical attachment, insensitive to existing magnetic fields, and operating over a wide temperature range, allowing for non-contact detection of torque, pressure, and tensile forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If strain gauge sensors are used to measure bending forces, then measurement capability is provided, but the shaft requires mounting elements or pre-processing that influence movement and reduce accessibility
Solution Approach 1:
The patent replaces mechanical attachment methods (mounting elements, pre-processing) with a magnetic field-based detection system. The sensor generates a magnetic field that interacts with the ferromagnetic shaft to detect bending forces without physical contact, eliminating the need for mechanical mounting while maintaining measurement capability
Solution Approach 2:
The patent introduces a magnetic field as an intermediary between the sensor and the shaft. The magnetic field carries the force measurement information without requiring direct mechanical contact, allowing the sensor to measure bending forces while the shaft maintains its movement freedom
2Ease of operation
If magnetic transducer elements are used for torque measurement, then non-contact measurement is achieved, but the shaft requires magnetization or mounting of magnetic elements
Solution Approach 1:
The patent utilizes the shaft's inherent ferromagnetic properties to enable non-contact measurement. The shaft itself serves as the magnetic medium that carries the force information, eliminating the need for additional magnetization or magnetic element mounting while achieving non-contact detection
3Object-affected harmful factors
If contactless magnetic sensing is implemented, then environmental resistance is improved, but the sensor must be insensitive to existing magnetic fields while detecting applied forces
Solution Approach 1:
The patent employs periodic excitation of the magnetic field at a known frequency. The sensor detects changes in the magnetic field at this frequency, allowing it to distinguish between the excitation field and ambient magnetic interference. This periodic action enables the sensor to be insensitive to existing magnetic fields while maintaining accurate force detection
Solution Approach 2:
The patent uses feedback mechanisms to compensate for ambient magnetic field interference. The sensor system continuously monitors and adjusts for external magnetic influences, maintaining measurement precision while achieving environmental resistance through active compensation
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
Enables accurate, non-invasive force measurement on rotating or static objects, resistant to environmental factors like light, dust, and humidity, with no need for object pre-processing, and can function with varying dimensions and surface conditions, enhancing usability in industrial and automotive applications.
Implementation Method 1
a first magnetic field generating unit (10a, 10b) being adapted for generating a magnetic field towards the facing orientation
Implementation Method 2
a first magnetic field detector unit (20a, 20b) being adapted for detecting a first magnetic field which field being generated by the first magnetic field generating unit and being influenced by an applied force to be measured
Data Source
Figure 1~2
Figure 3~4
Figure 5~6B
AI summary
A contactless force measurement sensor for measuring an applied force onto an object (2) is provided, the contactless force measurement sensor comprises a first facing orientation (zl) which facing orientation defines an orientation pointing towards a surface of the object, a first magnetic field generating unit (10a) being adapted for generating a magnetic field towards the facing orientation, a first magnetic field detector unit (20a) being adapted for detecting a first magnetic field which field being generated by the first magnetic field generating unit and being influenced by an applied force to be measured, wherein the first magnetic field detector unit is further adapted for outputting a first signal being representative for the detected magnetic field, and an evaluating unit (50) being adapted for evaluating a signal strength of the first signal and determining the applied force based on the first signal.