Sensor Head Nested Coil Arrangement for Load Measurement
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Solution Overview
Problem
Existing load measuring devices face challenges in distinguishing between magnetic field changes caused by torque, force, and position on ferromagnetic objects, particularly in harsh industrial environments, and are sensitive to distance variations and surface irregularities of test objects like shafts, limiting their broad industrial application.
Innovation Solution
A sensor head with a magnetic field generating unit and a measuring unit, featuring a specific arrangement of excitation and measuring coils, where the radially outermost excitation coil winding surrounds the measuring coil arrangement, reducing distance dependence and improving sensitivity to load changes while using a magnetic field conductor to enhance magnetic flux and reduce radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional sensor heads with planar coils are used, then the device can measure loads on ferromagnetic objects, but the measurement is highly sensitive to distance changes and surface irregularities
Solution Approach 1:
The patent transitions from conventional planar coil arrangements to a three-dimensional nested coil structure where excitation coils are positioned radially outside the measuring coils. This spatial reconfiguration in the radial dimension creates a magnetic field distribution that is less sensitive to axial distance variations, thereby reducing the harmful effect of distance dependence while maintaining load measurement accuracy.
Solution Approach 2:
The patent implements a nested coil arrangement where the measuring coil arrangement is positioned inside the excitation coil windings. This nested configuration allows the excitation field to be generated at a larger radius while the measuring coils detect changes at a smaller radius, creating a magnetic coupling that is less sensitive to distance changes and surface irregularities of the test object.
2Reliability
If active magnetization with alternating magnetic fields is used to compensate for distance sensitivity, then measurement stability improves, but the device complexity increases
Solution Approach 1:
The nested coil structure enables the system to automatically compensate for distance variations through its inherent magnetic field distribution characteristics. The excitation coils generating field at larger radius and measuring coils detecting at smaller radius create a self-regulating magnetic coupling that reduces sensitivity to distance changes without requiring external active magnetization systems or complex control mechanisms.
3Measurement precision
If the sensor head is positioned close to the test object to improve measurement sensitivity, then load detection accuracy improves, but the influence of surface irregularities and distance variations increases
Solution Approach 1:
By reconfiguring the coil arrangement in the radial dimension with excitation coils outside and measuring coils inside, the patent creates a magnetic field distribution that maintains sensitivity to load changes while reducing sensitivity to axial distance variations and surface irregularities. This dimensional reconfiguration allows the sensor to operate effectively without requiring extremely close positioning.
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 load measuring device with reduced sensitivity to distance changes and improved accuracy in measuring loads on test objects, enhancing its applicability in harsh industrial settings by stabilizing measurements across varying conditions.
Implementation Method 1
a magnetic field generating unit (16) for generating a magnetic field in the test object (14)
Implementation Method 2
detecting magnetic field changes. In particular, the torque transducer, the torque sensor and the measuring method are designed for the detection of magnetic field changes due to the Villari effect
Implementation Method 3
the ferromagnetic materials used change their permeability under the influence of tensile or compressive stresses (also called Villari effect)
Data Source
AI summary
A sensor head includes a magnetic field generating unit for generating a magnetic field in the test object and a magnetic field measuring unit for measuring a magnetic field change in the test object. The magnetic field generating unit includes at least one excitation coil having a plurality of excitation coil windings arranged around an excitation coil axis, and the magnetic field measuring unit includes a measuring coil arrangement having a plurality of measuring coils. The radially outermost excitation coil winding is arranged radially outside the measuring coil arrangement, as viewed with respect to the excitation coil axis, so that the measuring coil arrangement is surrounded by at least the radially outermost excitation coil winding, as viewed in axial plan view of the sensor head.