Rolling Bearing Strain Sensor Holder for Replaceable Deformation Sensing

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Solution Overview

Problem

Classically, strain sensors bonded to rolling bearings are permanent and cannot be replaced during service, limiting their effectiveness in condition monitoring and reliability prediction.

Innovation Solution

A piezoelectric strain sensor unit with a sensor holder featuring flexible arms and a central pin for three-point bending measurement, reducing parasitic stress and temperature influence, allowing for repeatable and dynamic deformation measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a strain sensor is permanently bonded to the rolling bearing surface, then the sensor provides continuous measurement capability, but the sensor cannot be replaced during service and accumulates parasitic stress from temperature changes

Engineering Contradiction:

Improvemeasurement reliabilityVSAvoidsensor replaceability

Core Design Contradiction:

ReliabilityVSEase of repair

Solution Approach 1:

The sensor system is divided into separate components: the piezoelectric strain sensor, the sensor holder with flexible arms, and the mounting interface. This segmentation allows the sensor to be easily removed and replaced by detaching it from the holder, while the holder remains mounted on the bearing. The flexible arms provide mechanical support while allowing thermal expansion/contraction without transmitting parasitic stress to the sensor.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The sensor holder acts as an intermediary between the rolling bearing and the piezoelectric strain sensor. The flexible arms in the holder serve as a mechanical mediator that supports the sensor while isolating it from temperature-induced stresses in the bearing, thereby eliminating parasitic stress accumulation while maintaining measurement capability.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Stability of the object's composition

If the piezoelectric strain sensor is rigidly supported, then the sensor structure is stable, but parasitic stress from temperature changes affects measurement accuracy

Engineering Contradiction:

Improvesensor structural stabilityVSAvoiddeformation measurement accuracy

Core Design Contradiction:

Stability of the object's compositionVSMeasurement precision

Solution Approach 1:

The sensor holder employs flexible arms that function as compliant mechanical elements. These flexible arms provide structural support for the piezoelectric strain sensor while accommodating thermal expansion and contraction of the rolling bearing without transmitting parasitic stresses to the sensor. This flexibility ensures measurement precision by isolating the sensor from temperature-induced deformations while maintaining positional stability.

Inventive Principle:

Principle #30Flexible shells and thin films

3Measurement precision

If the sensor is located close to the bearing surface for accurate measurement, then measurement accuracy improves, but the sensor is exposed to harmful thermal and mechanical environmental factors

Engineering Contradiction:

Improvedeformation detection accuracyVSAvoidtemperature and mechanical stress exposure

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The sensor holder with flexible arms serves as a protective intermediary that positions the piezoelectric strain sensor in optimal proximity to the rolling bearing for accurate deformation measurement, while simultaneously shielding the sensor from harmful thermal and mechanical environmental factors. The flexible arms transmit only the relevant mechanical deformation signals while filtering out parasitic thermal stresses.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 repeatable and accurate measurement of dynamic deformation in rolling bearings, enhancing condition monitoring and reliability prediction without the need for permanent bonding.

Implementation Method 1

A rolling bearing is provided with a piezoelectric strain sensor unit comprising a piezoelectric strain sensor and a sensor holder

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentUS11754454B2Piezoelectric strain sensor unit for a rolling bearing

Publication Date: 2023.09.12 AB SKF SKF PATENT DEPARTMENT

AI summary

A piezoelectric strain sensor unit for a rolling bearing includes a piezoelectric strain sensor, and a sensor holder provided with a main body having a front face intended to be into contact with a component of the rolling bearing and a rear face, and with at least two flexible arms mounted on the main body and supporting opposite ends of the piezoelectric strain sensor, the piezoelectric strain sensor being axially located on the side of the rear face of the main body while remaining spaced apart from the rear face. The sensor holder is provided with a central pin which protrudes axially with regard to the front face of the main body and which is axially moveable with regard the main body, the central pin axially abutting onto the piezoelectric strain sensor.