Rotary Machine Axial Mechanical Thrust Bearing Design

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Solution Overview

Problem

Rotary machines with magnetic bearings face challenges in manufacturing costs and electrical power consumption due to the need for continuous electrical power and the requirement of axial magnetic bearings, which can be costly and inefficient.

Innovation Solution

The implementation of an axial mechanical thrust bearing with a rolling element in direct axial contact with the rotor shaft, reducing power consumption and manufacturing costs by eliminating the need for axial magnetic bearings and decoupling the radial magnetic bearing function using elastic means, allowing the rotor to move freely without disturbing the radial magnetic bearings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If axial magnetic bearing is used to support rotor weight, then rotor is supported without mechanical friction, but manufacturing cost and electrical power consumption increase

Engineering Contradiction:
Improveelectrical power consumptionVSAvoidrotor support reliability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent replaces the axial magnetic bearing (electromagnetic system) with a mechanical thrust bearing consisting of a rolling element and flat surface. This substitution eliminates the need for continuous electrical power supply while maintaining reliable rotor support through direct mechanical contact in the axial direction.

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

Solution Approach 2:

The patent extracts the axial support function from the magnetic bearing system and assigns it to a dedicated mechanical thrust bearing. This separation allows the radial magnetic bearings to focus solely on radial suspension while the mechanical bearing handles axial weight support, reducing overall system complexity and power consumption.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of manufacture

If axial magnetic bearing is used for rotor support, then continuous rotor support is achieved, but manufacturing cost increases

Engineering Contradiction:
Improvemanufacturing costVSAvoidrotor support reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent replaces the expensive axial magnetic bearing with a simple mechanical thrust bearing comprising a rolling element and flat surface. This mechanical solution is significantly cheaper to manufacture while providing reliable axial support for the rotor weight.

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

Solution Approach 2:

The mechanical thrust bearing uses simple, inexpensive components (rolling element, flat surface) that can be easily replaced if needed, rather than using expensive magnetic bearing components. This approach prioritizes cost-effectiveness while maintaining functional reliability.

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

3Ease of manufacture

If axial mechanical thrust bearing is in direct contact with rotor shaft, then manufacturing cost is reduced, but wear of rolling element increases

Engineering Contradiction:
Improvemanufacturing costVSAvoidservice life of thrust bearing
Core Design Contradiction:
Ease of manufactureVSDuration of action of stationary object

Solution Approach 1:

The patent introduces a stator plate as an intermediary component between the rolling element and the rotor shaft. The rolling element contacts the stator plate while the rotor shaft contacts the stator plate's bearing surface, distributing the load and reducing wear on the rolling element while maintaining the mechanical thrust bearing's cost advantages.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Stability of the object's composition

If stator plate is fixed rigidly to stator casing, then axial support is stable, but radial magnetic bearing performance is disturbed

Engineering Contradiction:
Improveaxial support stabilityVSAvoidradial magnetic bearing performance
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent uses elastic means (flexible connection) to attach the stator plate to the stator casing. This flexible connection allows the stator plate to accommodate radial movements of the rotor while maintaining axial support stability, preventing disturbance to the radial magnetic bearing's active control function.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent transitions from a rigid fixed connection to a dynamic flexible connection using elastic means. This allows the stator plate to move slightly with the rotor's radial position changes while maintaining axial support, ensuring both axial stability and radial magnetic bearing performance.

Inventive Principle:
Principle #15Dynamics

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

This solution reduces manufacturing costs and electrical power consumption while ensuring the rotary machine's stability and performance by allowing the radial magnetic bearings to actively control the rotor's movement without radial forces, thus preventing damage and extending the service life of the mechanical thrust bearing.

Implementation Method 1

The stator plate is fixed to the stator casing by elastic means

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a rotary machine comprising magnetic bearings for supporting the weight and load of a rotor of the rotary machine by active magnetic bearings thanks to magnetic fields

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Data Source

PatentEP3154166B1Rotary machine having magnetic and mechanical bearings
Publication Date: 2022.11.30 SKF MAGNETIC MECHATRONICS SAS
  • EP3154166B1 patent drawingFigure 1
  • EP3154166B1 patent drawingFigure 2

AI summary

A rotary machine (10) comprises a stator (12) having a stator casing (18), and a rotor shaft (16) having a rotational axis (X-X) and supported in said stator casing (18) by at least one radial magnetic bearing (20, 22). The rotary machine (10) comprises an axial mechanical thrust bearing (24, 30) at the vicinity of a radial surface of one end (16b) of the rotor shaft (16), said axial mechanical thrust bearing (24, 30) comprising a rolling element (24a, 32) located on the rotational axis (X-X) of the rotor shaft (16).