Foil Segment Bearing Adjustable Gap Geometry

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Solution Overview

Problem

Foil bearings face challenges in maintaining optimal gap geometry due to manufacturing tolerances, leading to inefficiencies and potential shaft failure from either excessive or insufficient gap size, which existing technologies cannot effectively adjust post-assembly.

Innovation Solution

A foil segment bearing with an adjustable gap geometry mechanism using spring-loaded pins and bearing segments, allowing for dynamic spring rate adjustment and individual segment positioning to compensate for manufacturing tolerances and adapt to operating conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If fixed geometry bearing segments are used, then manufacturing precision is improved, but adaptability deteriorates

Engineering Contradiction:
Improvegap geometry precisionVSAvoidgap geometry adjustability
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The bearing segments are designed with movable adjustment mechanisms that allow the gap geometry to be dynamically changed after assembly. The segments can be positioned at different radial distances from the shaft center, enabling post-manufacturing adjustment of the bearing gap to compensate for tolerance variations and adapt to different operating conditions.

Inventive Principle:
Principle #15Dynamics

2Reliability

If sealing shims are added to stabilize the shaft, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improveshaft stabilityVSAvoidbearing structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The bearing is divided into multiple adjustable segments instead of using a continuous structure with sealing shims. Each segment can be independently positioned and adjusted, providing shaft stabilization through controlled gap variations without requiring additional sealing components. This segmentation approach achieves reliability while reducing structural complexity.

Inventive Principle:
Principle #1Segmentation

3Ease of manufacture

If gap geometry is fixed after assembly, then ease of manufacture is improved, but adaptability deteriorates

Engineering Contradiction:
Improveassembly simplicityVSAvoidoperating condition adaptation
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The bearing segments are pre-configured with adjustment mechanisms during manufacturing, allowing for simple assembly. However, the design incorporates preliminary adjustment capabilities that enable post-assembly modification of the gap geometry to adapt to different operating conditions, thus maintaining ease of manufacture while achieving adaptability.

Inventive Principle:
Principle #10Preliminary action

4Manufacturing precision

If manufacturing tolerances are strictly controlled, then manufacturing precision is improved, but cost increases

Engineering Contradiction:
Improvegap geometry toleranceVSAvoidproduction cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

Instead of strictly controlling manufacturing tolerances, the invention allows for broader tolerances during production and compensates through adjustable parameters after assembly. The bearing segments can be repositioned to achieve the desired gap geometry, eliminating the need for expensive tight tolerance manufacturing while maintaining precision in the final assembled product.

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

Enables precise radial positioning of the shaft, automatic centering, and flexible rigidity adaptation, preventing shaft failure by allowing adjustment of gap geometry within a controlled range, thus enhancing the bearing's efficiency and stability.

Implementation Method 1

The adjustment mechanism includes a spring and a pin, the spring being axially positionable by the pin. Due to the spring-loaded adjustment mechanism, the bearing segments are also spring-loaded so that they can give way during installation

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

At each of these constrictions, an aerodynamic pressure builds up, which carries the shaft and positions it in the radial direction

Methodology Applied
Scientific EffectAerodynamic pressure:

Data Source

PatentEP3237770B1Foil segment bearing, method for setting a gap geometry of a foil segment bearing and corresponding production method
Publication Date: 2019.11.06 ROBERT BOSCH GMBH
  • EP3237770B1 patent drawingFigure 1
  • EP3237770B1 patent drawingFigure 2~3
  • EP3237770B1 patent drawingFigure 4

AI summary

The invention relates to a foil segment bearing, to a method for setting a gap geometry of a foil segment bearing, and to a corresponding production method. The foil segment bearing (100) comprises a bearing backing (101) with a through opening (102), wherein a shaft (103) can be arranged in the through opening such that a gap (S) exists between the shaft and the bearing backing, at least one first and one second bearing segment (105a, 105b) with a respective inner surface (104a, 104b, 104c) which define a bearing surface (F) with an adjustable circumference (U), wherein the bearing segments (105a, 105b) are arranged in the bearing backing (101) at a distance from the shaft (103) such that a gap (S) exists between the shaft (103) and the bearing segments (105a, 105b), a foil arrangement (107; 107a, 107b) which can be arranged in the gap (S) between the inner surfaces of the bearing segments and the shaft (103), and an adjustment mechanism (110) which is set up in order to set a geometry of the gap.