Tilting Pad Bearing with Fluid-Film Biasing for Rotor Stability

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Solution Overview

Problem

Tilting pad bearings face challenges in achieving both increased rigidity to improve rotor shaft stability and reduced axial vibration, while minimizing heat-generated friction and preventing direct contact between the pad and rotor shaft.

Innovation Solution

A tilting pad bearing design that incorporates a pivot with a curved surface in contact with a linear liner, allowing for the pad to be biased towards the rotor shaft using a biasing member, while also enabling the supply of a fluid to create a film between the pad and rotor shaft.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the radial gap between the pad and rotor shaft is reduced to increase bearing rigidity, then rotor shaft stability improves, but heat generated by friction increases causing thermal expansion and potential direct contact

Engineering Contradiction:
Improverotor shaft stabilityVSAvoidheat generated by friction
Core Design Contradiction:
Stability of the object's compositionVSTemperature

Solution Approach 1:

The bearing is divided into multiple independent pads that can tilt and move relative to each other, allowing each pad to independently manage the gap and heat generation while maintaining overall bearing rigidity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The pads are designed to be dynamically adjustable through tilting and radial movement, enabling the bearing to adapt the gap size during operation to balance rigidity requirements with heat dissipation needs

Inventive Principle:
Principle #15Dynamics

2Stability of the object's composition

If a spring is added to bias the pad toward the rotor shaft to maintain contact, then bearing rigidity increases, but the structure becomes more complex requiring both spring biasing and fluid supply mechanisms

Engineering Contradiction:
Improvebearing rigidityVSAvoidstructure complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The spring biasing mechanism and fluid supply system are integrated into a unified structure where the spring serves dual purposes of maintaining pad contact and working in conjunction with the fluid supply to prevent direct contact during thermal expansion

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The spring mechanism performs multiple functions: biasing the pad toward the rotor shaft for rigidity, allowing thermal expansion clearance, and working with the fluid supply system to prevent direct contact, eliminating the need for separate mechanisms

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 design effectively increases the bearing's rigidity, improves rotor shaft stability, reduces axial vibration, and prevents direct contact between the pad and rotor shaft, while maintaining a simple structure for fluid supply and pad biasing.

Implementation Method 1

a fluid supply unit configured to supply a fluid from an outside of the housing to the pad surface

Methodology Applied
Scientific EffectFluid film lubrication: Lubrication

Implementation Method 2

a biasing member configured to bias the liner toward the pivot with respect to the housing

Methodology Applied
Scientific EffectElastic force: Spring

Data Source

PatentEP4253778B1Tilting pad bearing
Publication Date: 2025.01.29 MITSUBISHI HEAVY INDUSTIES COMPRESSOR CORP
  • EP4253778B1 patent drawingFigure 1
  • EP4253778B1 patent drawingFigure 2
  • EP4253778B1 patent drawingFigure 3

AI summary

Object Both a structure that enables supply of a fluid to the pad and a structure that biases the pad toward a rotor shaft are achieved with a simple structure. Solving Means A tilting pad bearing includes a plurality of pads slidably supporting an outside surface of a rotor shaft, a housing covering the plurality of pads, a support portion swingably supporting the pad with respect to the housing, and a fluid supply unit configured to supply a fluid to a pad surface. The support portion includes a pivot having a pad support surface in contact with a pad outside surface and a pivot curved surface curved facing and protruding toward a side opposite to the pad support surface, a liner having a first liner surface in contact with the pivot curved surface, and a biasing member biasing the liner toward the pivot with respect to the housing.