Fluid Cushion Guide for Contact-Free Cylindrical Alignment

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Solution Overview

Problem

Existing guiding devices for cylindrical members undergoing rotary and translational motion face issues with axis alignment, working tolerances, wear, and contamination due to physical contact, which complicates operations and requires lubrication, making them unsuitable for clean environments.

Innovation Solution

A fluid cushion guiding device with coaxial inner and outer cylindrical portions creates a pressurized fluid gap between the inner cylindrical portion and the member to be guided, using radial holes and controlled fluid introduction to maintain a uniform gap thickness, thereby avoiding contact and minimizing wear, and incorporating sensors and a control system to adjust fluid pressure for alignment compensation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If physical contact guiding devices (bushings, ball bushings) are used to guide cylindrical members, then guiding function is achieved, but wear of contacting surfaces occurs and lubrication is required

Engineering Contradiction:
Improveguiding functionVSAvoidwear and contamination
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent replaces the mechanical contact-based guiding system (bushings, ball bushings) with a fluid dynamic bearing system that uses aerodynamic forces to support and guide the rotor. The rotor is supported by an air cushion created by air injection through radial holes in the stator, eliminating solid-to-solid contact and thus preventing wear and the need for lubrication.

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

Solution Approach 2:

The patent employs pneumatic principles by injecting compressed air through radial holes in the stator to create an air cushion that supports the rotor. This pneumatic system replaces the mechanical contact guiding mechanism, allowing the rotor to rotate and translate without physical contact, thereby eliminating wear and contamination from lubrication.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Reliability

If physical contact guiding devices are used, then guiding is achieved, but alignment of axes and working tolerances become critical

Engineering Contradiction:
Improveguiding functionVSAvoidaxis alignment and tolerances
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent replaces the precision-critical mechanical contact system with a fluid dynamic system where the air cushion automatically adapts to misalignments. The aerodynamic bearing inherently compensates for axis misalignment and tolerance variations, eliminating the need for critical alignment and tight manufacturing tolerances required by traditional bushings.

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

3Ease of operation

If lubrication is used in contact guiding devices, then friction is reduced, but clean environment is compromised

Engineering Contradiction:
Improvefriction reductionVSAvoidcontamination
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent substitutes the lubrication-based friction reduction mechanism with an aerodynamic bearing system that eliminates the need for lubricants entirely. By using an air cushion to separate the rotor from the stator, the system achieves friction reduction without introducing any contamination, making it suitable for clean environment applications.

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

4Reliability

If contact-based guiding devices are used, then guiding is achieved, but overheating occurs due to friction

Engineering Contradiction:
Improveguiding functionVSAvoidoverheating
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent replaces the friction-generated heat problem in contact-based systems with a fluid dynamic system where the air cushion eliminates friction between the rotor and stator. Without direct contact, there is no frictional heating, thus preventing overheating while maintaining the guiding function.

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 prevents wear and contamination, maintains alignment, and ensures a clean environment by using a fluid cushion to guide the member, enhancing operational stability and suitability for applications requiring minimal bulk and cleanliness.

Implementation Method 1

creating a gap (or cushion) of pressurised fluid between the inner cylindrical portion and a member to be guided

Methodology Applied
Scientific EffectFluid cushion: Air Lubrication

Implementation Method 2

fluid volumes with uniform pressure are advantageously created at said end portions

Methodology Applied
Scientific EffectPressure distribution: Pascal's Law

Implementation Method 3

the pressure of the fluid volumes in the end portions increases where the thickness of the fluidic gap is smaller and decreases where the thickness is greater. This creates a pressure difference pushing the member to be guided towards the side where the fluidic gap has a greater thickness

Methodology Applied
Scientific EffectPressure difference: Pressure Gradient

Data Source

PatentEP3658793B1Fluid cushion guiding device
Publication Date: 2021.11.03 AROL
  • EP3658793B1 patent drawingFigure 1~2
  • EP3658793B1 patent drawingFigure 3~4
  • EP3658793B1 patent drawingFigure 5~7

AI summary

A fluid cushion guiding device (1) for guiding a member (2) into relative movement, rotary and/or translatory, relative to the guiding device (1), the guiding device (1) comprising an inner cylindrical portion (10) and an outer cylindrical portion (11) that are coaxial with each other. The inner cylindrical portion (10) has a plurality of radial holes (12) having first ends (13) communicating with a first gap (15) provided between the inner cylindrical portion (10) and the member (2) to be guided. The outer cylindrical portion (11) has at least one radial opening (17) arranged to allow introducing from the outside a pressurised fluid which, by reaching the first gap (15) through said holes (12), is suitable to create a fluidic gap between the inner cylindrical portion (10) and the member (2) to be guided.