Resistive Oil Particle Sensor: Magnetic Capture, Short-Circuit Prevention

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Solution Overview

Problem

Existing sensors for detecting abrasion powder in lubricating oil are prone to malfunction due to foreign matter causing short circuits, especially when large-diameter conductive pieces are present, leading to unexpected operation and reduced reliability.

Innovation Solution

Incorporating a short circuit preventing portion with a larger dimension than the gap between electrodes to prevent large-diameter conductive pieces from causing a short circuit, and using a magnet to gather conductive substances for resistance-based sensing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a sensor uses a pair of electrodes to detect conductive abrasion powder in lubricating oil, then it can sense the amount of abrasion powder through resistance changes, but large-diameter foreign matter can cause short circuits between the electrodes leading to unexpected operation

Engineering Contradiction:
Improvedetection accuracy of abrasion powderVSAvoidsensor malfunction due to short circuit
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent introduces a non-magnetic insulating material as an intermediary substance between the magnetic substance and the electrodes. This insulating material prevents direct contact between large-diameter conductive foreign matter and the electrodes, thereby avoiding short circuits while still allowing the magnetic substance to attract and concentrate abrasion powder for detection. The intermediary layer resolves the contradiction by maintaining detection functionality while preventing harmful short circuit effects.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If the gap between electrodes is made smaller to improve detection sensitivity, then the sensor can detect smaller amounts of abrasion powder, but it becomes more susceptible to short circuits from foreign matter

Engineering Contradiction:
Improvedetection sensitivityVSAvoidsusceptibility to short circuit from foreign matter
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The non-magnetic insulating material acts as a mediator that allows the electrode gap to remain small for high detection sensitivity while preventing foreign matter from bridging the gap and causing short circuits. The insulating layer fills the space between the magnetic substance and electrodes, maintaining the electric field for sensitive detection while blocking conductive paths from large foreign particles.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies different properties to different regions: the magnetic substance provides magnetic attraction for abrasion powder concentration, while the non-magnetic insulating material provides electrical insulation in the critical gap region. This local differentiation of material properties allows the system to achieve both high detection sensitivity and immunity to short circuits from foreign matter.

Inventive Principle:
Principle #3Local quality

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

Prevents unexpected sensor operation by preventing short circuits, ensuring reliable detection of abrasion powder levels and timely maintenance, thereby improving sensor reliability.

Implementation Method 1

a magnet to gather conductive substances

Methodology Applied
Scientific EffectMagnetic attraction: Magnetism

Implementation Method 2

Based on the resistance between the electrodes, which depends on the conductive substance attracted, the sensor senses the amount of the conductive substance in the oil

Methodology Applied
Scientific EffectElectrical resistance: Electrical Resistance

Data Source

PatentEP3742162B1Resistive-type sensor for sensing the amount of conductive particles contained in the lubricating oil
Publication Date: 2025.08.06 NABTESCO CORP
  • EP3742162B1 patent drawingFigure 1
  • EP3742162B1 patent drawingFigure 2
  • EP3742162B1 patent drawingFigure 3

AI summary

Resistive-type sensor for sensing the amount of conductive particles contained in a lubricating oil. The sensor includes a first electrode (6), a second electrode (8), an attracting portion (10) and a magnet (7) arranged between the first electrode and the second electrode, where the attracting portion attracts conductive particles smaller than a gap between the first electrode and the second electrode to cause a change in electrical resistance between the first electrode and the second electrode, and a short circuit preventing portion for preventing a large-diameter conductive piece from causing a short circuit between the first electrode and the second electrode, where the large-diameter conductive piece has a larger dimension than the gap between the first electrode and the second electrode.