Rolling Bearing Strain Sensor for Preload Measurement
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Solution Overview
Problem
Conventional rolling bearing devices with sensors face challenges in accurately and cost-effectively setting preload due to high manufacturing costs and errors related to sensor mounting accuracy, particularly with pressure sensors requiring deep grooves and multiple strain gauges.
Innovation Solution
A rolling bearing device with a sensor system that includes a thin, flexible film and foil affixed to the bearing surfaces, allowing for strain measurement through electrical conductivity changes, enabling accurate preload measurement with reduced groove depth and lower costs, and featuring a strain sensor with high-resistance portions for comprehensive deformation data collection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pressure sensor is used to measure preload, then measurement capability is achieved, but manufacturing cost increases and mounting accuracy errors occur
Solution Approach 1:
The patent replaces expensive pressure sensors with a cost-effective strain gauge system. The strain gauge consists of a flexible substrate with conductive patterns that can be manufactured at low cost using printing or deposition techniques, eliminating the need for costly commercial pressure sensors while maintaining measurement capability.
Solution Approach 2:
The patent substitutes a mechanical pressure sensing system with an electrical measurement system. Instead of using a mechanical pressure sensor that requires mounting adjustments, the invention uses electrical resistance changes in strain gauge patterns to detect preload, replacing mechanical sensing with electrical measurement.
2Measurement precision
If a pressure sensor with considerable thickness is used, then measurement function is provided, but groove depth must be increased leading to higher manufacturing cost
Solution Approach 1:
The patent employs a flexible substrate with conductive patterns that can be made extremely thin. This thin-film strain gauge system conforms to the bearing surface without requiring deep grooves, as the flexible nature of the thin film allows it to adapt to surface contours and mounting variations.
Solution Approach 2:
The strain gauge system is designed to be flexible and adaptable rather than rigid. The thin-film structure can dynamically conform to surface variations and mounting conditions, eliminating the need for precise groove depth control and deep groove formations.
3Measurement precision
If multiple strain gauges are used for comprehensive deformation measurement, then measurement accuracy improves, but device complexity and cost increase
Solution Approach 1:
The patent divides the strain gauge into multiple conductive patterns or segments on a single flexible substrate. These segmented conductive patterns can be arranged in series or parallel configurations to measure different strain components, providing comprehensive deformation measurement while maintaining a unified, simple structure.
Solution Approach 2:
The patent combines multiple measurement functions into a single integrated strain gauge system. By placing multiple conductive patterns on one flexible substrate and connecting them electrically, the system achieves comprehensive deformation measurement capability without the complexity of multiple separate strain gauges.
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 enables precise, low-cost preload measurement with reduced sensor thickness variations and improved accuracy, allowing for easy fitting on curved surfaces and comprehensive preload calculation without the need for multiple strain gauges, thus enhancing measurement accuracy and reducing manufacturing costs.
Implementation Method 1
a foil which is to be affixed onto the film and which has electrical conductivity, and a measurement section for measuring a current, voltage or resistance between a first place and a second place of the foil
Data Source
AI summary
In the rolling bearing device with a sensor in this invention, a band-shaped film 111 having insulation property is affixed to an outer circumferential surface of an outer ring 101 so as to extend in the circumferential direction. On the film 111 is affixed a foil 112 composed of identical four portions and having electrical conductivity which are placed at generally equal intervals in the circumferential direction of the outer ring 101. A resistance between a first place and a second place of the foil 112 is measured by a resistance measurement section of a microcomputer. A preload calculation section of the microcomputer, upon reception of an output from the resistance measurement section, calculates a preload of the outer ring 101 based on the measured resistance.