Squeeze Film Damper Bearing With Asymmetric Stiffness for Vibration Stability

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Solution Overview

Problem

Conventional bearing devices with squeeze film dampers do not provide sufficient vibration stability under high peripheral speed conditions, leading to unstable vibrations in rotary machines due to strong fluid forces.

Innovation Solution

A bearing device with a squeeze film damper featuring a plurality of pads and elastic bodies arranged to create differential stiffness in the vertical and horizontal directions, utilizing elastic bodies that repel radial forces to dampen vibrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional bearing device with a squeeze film damper uses a cylindrical cage spring member with uniform modulus of elasticity, then the damping performance is high, but the vibration stability under strong fluid forces is insufficient

Engineering Contradiction:
Improvevibration stabilityVSAvoidunstable vibrations caused by fluid force
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by making the modulus of elasticity of the elastic bodies non-uniform in the circumferential direction. Specifically, at least one elastic body has a different modulus of elasticity compared to others, creating localized stiffness variations that generate restoring forces to counteract fluid-induced vibrations and improve overall vibration stability.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements asymmetry by introducing elastic bodies with different modulus of elasticity values in the circumferential direction. This asymmetric configuration creates differential stiffness that generates stabilizing restoring forces when the bearing housing tilts under fluid forces, thereby suppressing unstable vibrations and improving reliability.

Inventive Principle:
Principle #4Asymmetry

2Reliability

If elastic bodies with different modulus of elasticity are used in the circumferential direction, then vibration stability is improved, but the device complexity increases

Engineering Contradiction:
Improvevibration stabilityVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent achieves improved vibration stability through local quality by varying the modulus of elasticity only in specific elastic bodies rather than redesigning the entire bearing structure. This localized modification maintains overall structural simplicity while introducing the necessary asymmetry to counteract fluid forces.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent applies parameter changes by modifying the modulus of elasticity parameter of the elastic bodies in the circumferential direction. This parameter variation creates the required asymmetric stiffness distribution to improve vibration stability without fundamentally changing the device structure, thereby limiting the increase in complexity.

Inventive Principle:
Principle #35Parameter changes

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 bearing device achieves high vibration stability by effectively suppressing unstable vibrations caused by fluid forces, enhancing the stability of rotating shafts in rotary machines.

Implementation Method 1

each of the squeeze film damper parts includes a plurality of elastic bodies that repel a radial force

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

bearing device with a squeeze film damper

Methodology Applied
Scientific EffectViscous damping: Viscous Damping

Data Source

PatentEP4632242A1Bearing device with squeeze film damper, and centrifugal compressor
Publication Date: 2025.10.15 HITACHI IND PROD LTD
  • EP4632242A1 patent drawingFigure 1
  • EP4632242A1 patent drawingFigure 2
  • EP4632242A1 patent drawingFigure 3

AI summary

The present invention is to provide a bearing device with a squeeze film damper, which is able to obtain high vibration stability, and to provide a centrifugal compressor including the bearing device. A bearing device (1) with a squeeze film damper according to the present invention includes a plurality of pads (3) that constitute a bearing surface supporting a rotating shaft (2), a bearing housing (4) that accommodates the pads (3), a housing (5) that is located outside the bearing housing (4) in a radial direction, and a plurality of squeeze film damper parts (7) arranged in a circumferential direction at a clearance (11) between the bearing housing (4) and the housing (5). Each of the squeeze film damper parts (7) includes a plurality of elastic bodies (6) that repel a radial force. The plurality of elastic bodies (6) are set such that overall stiffness is different between in a vertical direction and in a horizontal direction.