Sensor-Bearing Unit Oil Flow and Detection Design

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Solution Overview

Problem

Existing sensor-bearing units are not adapted for oil-lubricated environments, as they often have complex structures that hinder oil flow and are prone to oil contamination, reducing efficiency.

Innovation Solution

A compact and practical sensor-bearing unit design that allows oil to flow freely through the bearing, with a detection device fixed to the bearing and optimized air gaps between the target and sensor, using materials resistant to oil aggression, and featuring open passages for unobstructed oil flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If sealing members are added to prevent oil leakage, then oil containment is improved, but device complexity increases

Engineering Contradiction:
Improveoil containmentVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the sealing function with the existing retainer structure. The retainer serves dual purposes: mechanically retaining the sensor and simultaneously sealing the bearing from oil. This merging eliminates the need for separate sealing members, resolving the contradiction between reliability and device complexity.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If a sensor cover is extended to form a shield, then sensor protection is improved, but oil flow is obstructed

Engineering Contradiction:
Improvesensor protectionVSAvoidoil flow efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent extracts the sensor protection function from the oil flow path. Instead of extending the sensor cover to form a shield that blocks oil, the solution positions the sensor and its minimal cover outside the main oil flow path. The retainer structure protects the sensor while allowing oil to flow freely through the bearing, resolving the contradiction between sensor protection and oil flow efficiency.

Inventive Principle:
Principle #2Taking out (Extraction)

3Volume of moving object

If the detection device is made compact, then space utilization is improved, but oil flow passage is reduced

Engineering Contradiction:
Improvedetection device sizeVSAvoidoil flow rate
Core Design Contradiction:
Volume of moving objectVSProductivity

Solution Approach 1:

The patent resolves the spatial conflict by changing the dimensional arrangement. The compact detection device is positioned in a location that does not interfere with the axial oil flow path through the bearing. The sensor and target are arranged radially close for compactness, while the axial dimension maintains full oil flow passage, allowing both compactness and adequate oil flow to coexist.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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

Enables efficient operation in oil-lubricated environments by ensuring uninterrupted oil flow and minimizing contamination, resulting in a more reliable and efficient tracking of rotation.

Implementation Method 1

The detection device usually comprises a sensor fixed to the non-rotating ring and a target fixed to the rotating ring of the bearing

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Data Source

PatentEP2852844B1Sensor-bearing unit and apparatus comprising such a unit
Publication Date: 2019.07.10 AB SKF SKF PATENT DEPARTMENT
  • EP2852844B1 patent drawingFigure 1
  • EP2852844B1 patent drawingFigure 2
  • EP2852844B1 patent drawingFigure 3~4

AI summary

The invention relates to a sensor-bearing unit (10), adapted for implementation in an oil lubricated environment and comprising: a bearing (20) including at least one rotating ring (30) movable in rotation around a central axis (X1), and a detection device (60) for tracking the rotation of the rotating ring (30), the detection device (60) being locked to the bearing (20) and including at least one target (70) and at least one sensor (80) associated with the target (70), wherein at least one axial side (22, 23) of the bearing (20) includes a passage (24, 25) opened along an axial direction parallel to the central axis (X1) and allowing an oil flow through the bearing (20), and wherein the detection device (60) includes an air gap (90) defined radially to the central axis (X1) between a maximum outer radius (r70) of the target (70) and a minimum inner radius (r80) of the sensor (80).