Bearing Test Device Using Magnetic Torque Coupling

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Solution Overview

Problem

High-speed traction motor bearings face challenges due to increased friction and vibrations, leading to wear issues, as conventional bearing architectures are not suitable for high-speed applications, and there is a need to find a compromise between preload and radial clearance to extend service life without compromising bearing cage integrity.

Innovation Solution

A device and method for testing bearing parameters, comprising a rotor, transmission shaft, and bearings, with an electronic inclination sensor to measure angular position and torque, allowing comparison of influence on resistive torque and bearing life, enabling the determination of optimal preload and clearance settings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If preload is reduced or positive clearance is allowed to extend bearing life, then bearing service life is improved, but bearing cage lifespan is detrimentally affected

Engineering Contradiction:
Improvebearing service lifeVSAvoidbearing cage lifespan
Core Design Contradiction:
Duration of action of moving objectVSReliability

Solution Approach 1:

The patent replaces traditional mechanical torque measurement systems with magnetic coupling and Hall effect sensors. The magnetic coupling transmits torque from the inner ring to the outer ring without direct mechanical contact, while Hall effect sensors detect the angular position of the outer ring to calculate torque. This substitution eliminates mechanical interference with the bearing cage, allowing accurate torque measurement without compromising bearing cage lifespan.

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

Solution Approach 2:

The patent introduces magnetic fields as an intermediary to transmit torque information from the bearing to the measurement system. The magnetic coupling acts as a mediator that transfers torque data without requiring direct mechanical connection, enabling torque measurement while maintaining bearing integrity and avoiding negative effects on the bearing cage.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If conventional ball bearing and roller bearing architecture is used, then manufacturing ease is improved, but vibration level increases making it unsuitable for high speeds

Engineering Contradiction:
Improvebearing architecture implementationVSAvoidvibration level
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent changes the fundamental parameters of the bearing architecture by using magnetic coupling instead of traditional mechanical contact between inner and outer rings. This parameter change allows the bearing to operate at high speeds with reduced vibration while maintaining ease of manufacture through modular assembly of magnetic components.

Inventive Principle:
Principle #35Parameter changes

3Speed

If rotor heats up and expands at high speed, then high-speed operation is achieved, but radial play in bearings is reduced

Engineering Contradiction:
Improverotational speedVSAvoidradial play
Core Design Contradiction:
SpeedVSLength of moving object

Solution Approach 1:

The patent replaces direct mechanical measurement of radial play with magnetic coupling and Hall effect sensor measurement. The magnetic field penetrates through the thermal expansion of the rotor without being affected by dimensional changes, allowing continuous measurement of bearing parameters despite thermal expansion at high speeds.

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

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 allows for the prediction of bearing behavior, enabling a compromise between preload and radial clearance, thereby extending the service life of high-speed traction motor bearings while minimizing detrimental effects on the bearing cage.

Implementation Method 1

a tilt measuring device comprising an electronic tilt sensor fixed to the bearing housing and arranged to measure and record at regular intervals an angular position of the electronic tilt sensor

Methodology Applied
Scientific EffectElectronic tilt sensing: Accelerometer

Implementation Method 2

The inner ring is magnetically coupled to the outer ring so that friction forces generated in the bearing are transmitted in the form of a torque to the outer ring

Methodology Applied
Scientific EffectMagnetic coupling: Magnetic Field

Implementation Method 3

At least one angle sensor in the form of a Hall effect sensor is arranged on the outer ring

Methodology Applied
Scientific EffectHall effect: Hall Effect

Implementation Method 4

friction forces generated in the bearing are transmitted in the form of a torque to the outer ring

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3936848B1Device for testing parameters relative to at least one bearing, and associated testing method
Publication Date: 2022.09.28 ALSTOM TRANSPORT TECH SAS
  • EP3936848B1 patent drawingFigure 1
  • EP3936848B1 patent drawingFigure 2
  • EP3936848B1 patent drawingFigure 3

AI summary

The test device (10) comprises at least: (a) a rotor, (b) a drive shaft (12) connected to the rotor, (c) at least one bearing to be tested (14), (d) a bearing housing (16), (e) an external bearing (18), the bearing to be tested (14) being fixed around the drive shaft (12) and fitted into the bearing housing (16), the external bearing (18) being arranged around the bearing housing (16) so that the bearing housing (16) is free to rotate around the bearing to be tested (14), and (f) a tilt measuring device (20) comprising an electronic tilt sensor (22) fixed to the bearing housing (16) and arranged to measure and record at regular intervals an angular position of the electronic tilt sensor (22).