Tilting Pad Bearing Cage Structure for Oil-Free Misalignment Control

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Solution Overview

Problem

Existing tilting segment bearings face challenges in efficiently supporting high-speed shafts with minimal loss and accommodating angular misalignments, particularly in applications like turbo compressors and fuel cell systems, where traditional lubrication methods can be detrimental.

Innovation Solution

The implementation of a tilting segment bearing with a frame-like spring device and rolling elements, such as balls or rollers, that allow for tilting movements and are supported by a cage design with through holes to position and stabilize the rolling elements between the housing body and rotor, enabling efficient rotation and alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If traditional lubrication methods (oil or grease) are used in bearings, then friction is reduced, but contamination occurs in fuel cell systems requiring oil-free compressed air

Engineering Contradiction:
ImprovefrictionVSAvoidcontamination
Core Design Contradiction:
Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The patent employs a gas-lubricated bearing system where compressed air serves as the lubricant instead of traditional oil or grease. The bearing design includes gas distribution channels that deliver compressed air to the bearing surfaces, creating a gas film that separates moving parts and reduces friction without introducing contamination into the fuel cell system.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Productivity

If high-speed rotation is achieved in shafts, then productivity increases, but bearing losses and friction increase

Engineering Contradiction:
Improverotational speedVSAvoidbearing losses
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The gas-lubricated bearing utilizes compressed air to create a lubricating film that minimizes friction and bearing losses even at very high rotational speeds. The gas film formation and distribution are optimized to maintain effective lubrication under high-speed conditions, enabling the shaft to rotate with minimal energy loss.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The bearing design incorporates parameters optimized for high-speed operation, including specific gas pressure levels, film thickness control, and geometric parameters of the bearing surfaces. These parameters are adjusted to ensure stable gas film formation and minimal friction across the operating speed range.

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If tilting segments are held rigidly in the housing, then structural stability is improved, but angular misalignments cannot be compensated

Engineering Contradiction:
Improvestructural stabilityVSAvoidmisalignment compensation
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The tilting segments are designed with controlled mobility, allowing them to tilt and adjust their orientation in response to angular misalignments between the shaft and housing. The segments are supported by rolling elements that enable smooth tilting movements while maintaining stable contact with the shaft surface. This dynamic adjustment capability allows the bearing to compensate for misalignments without sacrificing overall structural stability.

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 configuration minimizes friction and bearing losses at high speeds, eliminates the need for oil or grease lubrication, and effectively compensates for angular misalignments, making it suitable for high-speed applications like turbo compressors and fuel cell systems.

Implementation Method 1

a spring element (43) assigned to each tilting segment (1-3) for positioning and holding the assigned tilting segment (1-3) tiltably within the housing body (5in)

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 2

The rolling elements advantageously serve to enable the tilting movements of the tilting segments

Methodology Applied
Scientific EffectRolling friction: Friction

Implementation Method 3

Gas-lubricated bearings are advantageously used for support, as they exhibit very low friction at very high rotational speeds and therefore only minimal bearing losses

Methodology Applied
Scientific EffectGas lubrication: Lubrication

Data Source

PatentEP4146948B1Tilting pad bearing
Publication Date: 2024.05.08 ROBERT BOSCH GMBH
  • EP4146948B1 patent drawingFigure 1~2
  • EP4146948B1 patent drawingFigure 3~4
  • EP4146948B1 patent drawingFigure 5~6

AI summary

The invention relates to a tilting pad bearing (10) comprising tilting pads (1, 2, 3), which are retained and positioned so that they can tilt in a housing body (8) with a frame-type spring unit (8), such that, during operation of the tilting pad bearing (10), converging bearing gaps are created between the tilting pads (1,2,3) and a rotor body (4) that is rotatably mounted about an axis of rotation. In order to improve the functioning and/or manufacturing of the tilting pad bearing (10), the tilting pad bearing (10) is characterised by rolling elements (6, 7) arranged between the housing body (5) and the tilting pads (1,2, 3).