Bearing Sensor Unit Embedded in Ring Recess

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Solution Overview

Problem

Existing sensor units for bearings are prone to damage from collisions and provide inaccurate measurements due to their surface-mounted configuration, which is remote from the rolling elements and lacks robustness.

Innovation Solution

Embedding the sensor unit within a recess of the bearing's inner or outer ring, closer to the rolling elements, and using a wireless transmitter, circlip for fixation, and adhesive sealing to enhance precision and protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the sensor unit is mounted on the surface of the bearing using adhesion or screws, then the assembly is simple and cost-effective, but the sensor housing is susceptible to damage from collisions and the measurement precision is reduced due to distance from rolling elements

Engineering Contradiction:
Improvesensor protectionVSAvoidsensor unit configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The sensor unit is embedded within a recess in the bearing ring, nesting the sensor housing inside the bearing structure itself. This protects the sensor from external collisions while maintaining integration with the bearing, eliminating the need for separate surface-mounted housings.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The recess is created locally in the bearing ring at the specific position where sensor placement is required. This localized structural modification provides protection and precise positioning without requiring complex changes to the entire bearing assembly.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If the sensor is mounted on the surface of the bearing, then the installation is straightforward, but the measurement precision is compromised due to remote positioning from rolling elements

Engineering Contradiction:
Improvestrain measurement accuracyVSAvoidsensor unit installation
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

By nesting the sensor unit within the bearing ring's recess, the sensor achieves optimal proximity to the rolling elements for precise measurement, while the recess structure itself provides the mounting function, simplifying installation.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The recess is pre-formed in the bearing ring during manufacturing, so that when the sensor unit is installed, it automatically achieves the correct position and orientation for high-precision measurement without requiring additional alignment steps.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If screws or bolts are used to fix the sensor unit, then the fixation is secure, but the strain measurement is adversely affected by the fastening elements

Engineering Contradiction:
Improvesensor fixationVSAvoidstrain measurement
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The fastening elements (screws or bolts) that adversely affect strain measurement are completely removed from the design. Instead, the sensor unit is retained in the recess using alternative methods such as interference fits, adhesive bonding, or circumferential notches that do not interfere with strain measurement.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The recess structure itself serves as the retention mechanism, eliminating the need for separate fastening components. The bearing ring's own structure is used to hold the sensor unit securely without adding extraneous elements that would affect measurement.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Data Source

PatentEP2979073B1Bearing including sensor unit.
Publication Date: 2018.08.08 AB SKF SKF PATENT DEPARTMENT
  • EP2979073B1 patent drawingFigure 1~2
  • EP2979073B1 patent drawingFigure 3~4
  • EP2979073B1 patent drawingFigure 5~6

AI summary

The invention relates to a sensor unit (14) for a bearing including at least one inner ring (10) and at least one outer ring (12), wherein the sensor unit (14) is configured to detect at least one state variable of the bearing. It is proposed that the sensor unit (14) is embedded in a recess (26) of the inner ring or the outer ring (10, 12).