Air Bearing Groove Machining With Sinusoidal One-Pass Cutting

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Solution Overview

Problem

High-speed centrifugal fluid compressors face challenges with frictional heating due to mechanical contact between the rotor shaft and air or gas bearings, and existing machining methods for creating grooves or ribs are time-consuming and costly.

Innovation Solution

A method for quickly producing V-shaped grooves or ribs on the rotor shaft using a machining machine with synchronized sinusoidal programming and reciprocating tool movements, allowing the shaft to rotate virtually frictionlessly within the bearings by generating air or gas pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If laser machining is used to create grooves or ribs in air or gas bearings, then the grooves can be created, but the machining time is too long and costs are too high

Engineering Contradiction:
Improvegroove precisionVSAvoidmachining speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent replaces traditional laser machining with a specialized mechanical machining process using a rotating tool that cuts grooves or ribs in the bearing surface. This mechanical approach achieves the same functional result (creating pressure distribution patterns) but with significantly faster machining speed and lower cost, while maintaining the required precision for high-speed compressor operation

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

Solution Approach 2:

The invention changes the machining parameters by using a rotating tool with specific speed and feed rate ratios, creating a dynamic machining process rather than static laser processing. This allows for rapid material removal while controlling groove geometry, achieving both high productivity and acceptable manufacturing precision

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If traditional machining methods are used to create grooves or ribs, then the process is simple, but the machining time is too long

Engineering Contradiction:
Improveprocess simplicityVSAvoidmachining time
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The patent employs periodic reciprocating motion of the machining tool combined with continuous rotation of the bearing, creating a rhythmic cutting action that efficiently removes material. The tool moves forward, cuts, reverses, and repeats this cycle while the bearing rotates, achieving rapid groove formation without complex continuous-path programming

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The invention introduces dynamic elements to the machining process by synchronizing the reciprocating tool motion with the rotational speed of the bearing. This dynamic coordination allows the simple mechanical tool to create precise grooves rapidly, transforming a static machining operation into a time-efficient dynamic process

Inventive Principle:
Principle #15Dynamics

3Temperature

If air or gas bearings are designed without friction support, then frictional heating is reduced, but the bearings cannot support the rotor shaft without mechanical contact

Engineering Contradiction:
Improvefrictional heatingVSAvoidbearing support capability
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent uses pneumatic principles by introducing pressurized air or gas through the bearing surface, creating a fluid film that separates the rotor shaft from the bearing. The grooves or ribs machined into the bearing surface generate hydrodynamic pressure in the air/gas film, enabling frictionless support and eliminating frictional heating while maintaining reliable load-bearing capability

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The invention introduces an air or gas film as an intermediary between the rotor shaft and bearing surface. This fluid mediator carries the load through pressure generation in the grooved regions, allowing the shaft to be supported without direct mechanical contact, thus eliminating friction and associated heating while preserving support functionality

Inventive Principle:
Principle #24Intermediary (Mediator)

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 method enables the high-speed centrifugal fluid compressor to operate without excessive heating, achieving precise and rapid machining of grooves or ribs, reducing mechanical friction and increasing efficiency.

Implementation Method 1

the reciprocating movements of the machining tool are synchronized with the sinusoidal programming performed in the machining center

Methodology Applied
Scientific EffectSinusoidal motion: Harmonic Oscillator

Implementation Method 2

the air or gas bearings supporting the motor shaft on one side and the electronic components on the other... the shaft to rotate virtually frictionlessly within the bearings by generating air or gas pressure

Methodology Applied
Scientific EffectAir bearing: Air Lubrication

Data Source

PatentEP4180154A1Method for machining ribs or grooves for gas or air bearings of a compressor
Publication Date: 2023.05.17 THE SWATCH GRP RES & DEVELONMENT LTD
  • EP4180154A1 patent drawingFigure 1~2b
  • EP4180154A1 patent drawingFigure 3~5
  • EP4180154A1 patent drawingFigure 6~8

AI summary

The invention relates to a method for machining ribs or grooves on a workpiece such as a shaft (7) or an air or gas axial bearing (24) to be rotated about a longitudinal axis of a centrifugal compressor. According to the method, all the ribs or grooves (32, 24a) are obtained on a portion to be machined from the rotating workpiece by moving the workpiece or the tool holder in a longitudinal machining direction, in a single pass, by the machining tool performing reciprocating movements with a machining position in contact with the workpiece and a position without contact with the workpiece from the beginning to the end of the portion to be machined. The reciprocating movements of the machining tool are synchronized with the sinusoidal programming performed in the machining machine, as well as with the desired and programmed arrangement of the ribs or grooves to be made on the portion of the workpiece.