Radio Sensor for Preload Force Monitoring in Screw Connections
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Solution Overview
Problem
Existing methods for monitoring and documenting preload forces in screw connections, especially in pressure-loaded systems and hard-to-reach locations, face challenges such as distorted measurement results and difficulty in managing large numbers of connections, due to the arrangement of sensor elements within the force flow and the need for distinct resonant frequencies.
Innovation Solution
A radio sensor with automatic measurement acquisition and a position measuring system is integrated into a hydraulic clamping device, allowing for the detection and transmission of preload forces via a radio link, eliminating the need for mechanical contact and enabling efficient logging and monitoring of multiple screw connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensor elements are arranged within the force flow of the screw connection, then preload forces can be measured, but the forces acting on the sensor element distort the measurement result
Solution Approach 1:
The sensor is extracted from the force flow path and positioned on the external surface of the screw connection. The magnetic field sensor detects preload forces through magnetic field changes caused by shaft elongation, without being subjected to the mechanical forces that would distort measurements in traditional embedded sensor arrangements.
Solution Approach 2:
A magnetic field is introduced as an intermediary between the preload force and the sensor measurement. The preload force causes shaft elongation, which changes the magnetic field distribution, and the magnetic field sensor detects these changes without directly bearing the mechanical load.
2Ease of operation
If resonant circuits are used for wireless monitoring of screw connections, then data can be transmitted without cables, but the natural frequencies must be designed to be so different from one another that monitoring a large number of screw connections becomes difficult
Solution Approach 1:
The mechanical resonant circuit system is replaced with a magnetic field-based sensor system. Instead of using electromagnetic resonance at different frequencies, the system uses a single magnetic field sensor that detects shaft elongation through magnetic field changes, eliminating the need for frequency differentiation and simplifying the monitoring of multiple screw connections.
3Measurement precision
If mechanical dial gauges are used for measuring preload forces, then measurements can be obtained, but documentation must be done manually which is time-consuming
Solution Approach 1:
The system performs automatic self-measurement and self-documentation. The magnetic field sensor continuously monitors shaft elongation and the integrated electronics automatically record the preload force data, eliminating the need for manual reading and documentation while maintaining measurement accuracy.
Solution Approach 2:
The mechanical dial gauge system is replaced with an electronic magnetic field sensor system that provides automatic digital measurement and recording. The electronic system eliminates manual intervention by automatically detecting, processing, and storing the preload force data.
4Reliability
If cable connections are used for sensor data transmission, then data can be transmitted reliably, but the complexity and cost of managing large numbers of cable connections increases
Solution Approach 1:
Physical cable connections are replaced with wireless magnetic field-based data transmission. The magnetic field sensor and integrated electronics transmit preload force data wirelessly, eliminating the physical cable infrastructure and its associated management complexity while maintaining data reliability.
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
This solution provides accurate and efficient documentation and monitoring of preload forces with minimal data transmission, reducing the complexity and cost of managing large numbers of screw connections, while enhancing operational safety by enabling real-time data processing and fault detection.
Implementation Method 1
the position measuring system is designed to detect the position of the piston by means of electromagnetic radiation
Implementation Method 2
transmitting the measurement values to the memory arranged remotely from the screw connection via a radio link
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
The arrangement has a measuring sensor arranged in a screw connection for detecting a measurement parameter. The measuring sensor is formed as radio sensor (12) with data logging, and a storage for the measurement value is arranged remote from the screw connection. The storage is connected with the radio sensor through a radio line, and the radio sensor has a path measuring system. A shaft (3) has an opening (9) in an axial direction, and the opening has an inner thread (10) at a side. An independent claim is also included for a method for operating an arrangement of detecting measurement parameter in a screw connection.