Shaft Axial Movement Detection Using Conductive Sliding Contact

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Solution Overview

Problem

Existing technologies lack a simple and reliable method to detect axial movement of a shaft, which can indicate abnormal operating conditions such as pre-surge or surge in applications like turbochargers, potentially leading to damage.

Innovation Solution

A sliding contact arrangement between two parts, one with an electrically conductive surface and a sensor made of conductive material, forming a closed or open electrical circuit based on contact, allowing for detection of axial movement using resistance measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a simple contact-based detection method is used, then device complexity is reduced, but measurement precision and reliability may be insufficient

Engineering Contradiction:
Improvedetection arrangement complexityVSAvoidaxial movement detection precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces complex mechanical detection systems with a simple electrical contact principle. The sensor uses electrical conductivity changes to detect axial movement, substituting mechanical linkages and complex sensors with a basic conductive contact between the first and second parts, significantly reducing device complexity while maintaining detection capability

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The detection arrangement utilizes the existing axial movement of the shaft itself to activate the detection mechanism. The shaft's movement directly causes the first and second parts to contact or separate, eliminating the need for separate actuation mechanisms and reducing overall system complexity

Inventive Principle:
Principle #25Self-service

2Reliability

If a reliable detection method is implemented, then detection accuracy improves, but device complexity increases

Engineering Contradiction:
Improveaxial movement detection reliabilityVSAvoiddetection arrangement complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs electrical conductivity as the detection mechanism, replacing complex mechanical sensors with a simple conductive contact system. The electrical circuit formed when parts contact provides reliable detection signals without requiring complex mechanical measurement devices

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The detection system monitors changes in electrical conductivity parameters to detect axial movement. By measuring whether the electrical circuit is closed or open, the system reliably detects the shaft's axial position changes using electrical parameter changes rather than complex mechanical measurements

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If contact-based electrical detection is used, then device simplicity is achieved, but durability under sliding contact conditions may be compromised

Engineering Contradiction:
Improvedetection arrangement complexityVSAvoidsliding contact durability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent accepts that the contact surfaces may wear over time but designs the detection system to remain functional throughout the service life. The simple conductive contact elements can be replaced if needed, and the detection principle remains valid even with some wear, maintaining system simplicity while managing durability through straightforward replacement rather than complex protective mechanisms

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

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 early detection of axial movement, preventing damage by providing a straightforward means to monitor and respond to abnormal operating conditions in devices like turbochargers.

Implementation Method 1

which sensor is made at least partly of an electrically conductive material and comprises a first area and a second area, which first area is electrically connected to the electrically conductive surface of the second part. The second area is in electrical contact with the electrically conductive surface of the second part when the first part and the second part are in sliding contact with each other so that a closed electrical circuit is formed.

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP2561186B1Arrangement for detecting axial movement of a shaft
Publication Date: 2015.08.12 WARTSILA FINLAND OY
  • EP2561186B1 patent drawingFigure 1
  • EP2561186B1 patent drawingFigure 2
  • EP2561186B1 patent drawingFigure 3

AI summary

An arrangement for detecting axial movement of a shaft (9), which arrangement comprises a first part (1) and a second part (2), the second part (2) comprising a surface (2a) being made of an electrically conductive material. The shaft is attachable to the first part (1) or to the second part (2)and the surface (2a) can be brought into sliding contact with the first part (1)and apart from it. The arrangement further comprises a sensor (3) being made at least partly of an electrically conductive material and arranged in the first part (1). The sensor (3) comprises a first area (3d) that is electrically connected to the surface (2a) of the second part (2)and a second area (3e) that is in electrical contact with the surface (2a) of the second part (2) when the first part (1) and the second (2) part are in sliding contact with each other so that a closed electrical circuit is formed. When the first part (1) and the second part (2) are at a distance from each other, the second area (3e) is at a distance from the surface (2a)of the second part (2) so that an open electrical circuit is formed. The arrangement also comprises means (5) for detecting opening and closing of the electrical circuit.