FAG Aerospace GmbH

St. Georg, Germany

FAG Aerospace GmbH

St. Georg, Germany

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Gloeckner P.,FAG Aerospace GmbH | Dullenkopf K.,Karlsruhe Institute of Technology | Flouros M.,MTU Aerospace Engines GmbH
Journal of Engineering for Gas Turbines and Power | Year: 2011

Operating conditions in high speed mainshaft ball bearings applied in new aircraft propulsion systems require enhanced bearing designs and materials. Rotational speeds, loads, demands on higher thrust capability, and reliability have increased continuously over the last years. A consequence of these increasing operating conditions are increased bearing temperatures. A state of the art jet engine high speed ball bearing has been modified with an oil channel in the outer diameter of the bearing. This oil channel provides direct cooling of the outer ring. Rig testing under typical flight conditions has been performed to investigate the cooling efficiency of the outer ring oil channel. In this paper, the experimental results including bearing temperature distribution, power dissipation, and bearing oil pumping and the impact on oil mass and parasitic power loss reduction are presented. © 2011 American Society of Mechanical Engineers.


Rolling element bearings undergo high dynamic loading in the region of the contact areas. If the stress level caused by the contact of the curved bodies exceeds a material specific limit, material fatigue can occur which limits the lifetime of a bearing. By defined induced residual stresses in the surface near region the lifetime of bearings can be increased considerably. In order to get data, rig tests were performed at FAG with bearing components made from the high speed steel M50. Besides a statistical evaluation of the test results investigation of the tested bearing parts by metallografic inspection methods and by X-ray diffraction analysis has been performed. The sensitivity in detection of structural changes by X-ray methods is high, therefore an assessment of the effectivity of induced residual stresses is possible after a comparatively short time rig testing. © Carl Hanser Verlag GmbH & Co. KG.


Ebert F.-J.,FAG Aerospace GmbH
Chinese Journal of Aeronautics | Year: 2010

This article presents an overview of fundamentals of rolling element bearing designs and technologies. The aim is to outline the complex interrelation of all fundamentals with the rolling contact fatigue and the attainable bearing life. Such fundamentals include, amongst others, bearing stressing and life capability. The article shows the different types of rolling bearing stressing and the analysis of the stress distribution (principal stresses and equivalent stresses) in the material under the rolling contact area. It becomes obvious that the contamination of the bearing with foreign particles leads to a drastic reduction in bearing life. Furthermore, it demonstrates the impact of the bearing lubrication and coating as well as the effect of additives on the attainable life and wear. Further fundamentals of rolling element bearing design are the materials, the material cleanliness and the heat treatment. The article reveals the importance of the cleanliness of bearing steels as well as different types of inclusions and their effect on rolling contact fatigue. Additionally the article describes how to optimize the material properties (strength, toughness and residual stress) by the heat treatment processes. The outcome of these investigations is that endurance life of a rolling element bearing can be achieved if specific operating conditions, an adequate lubrication, good system cleanliness and specific bearing stressing are met. The article provides a guideline for bearing engineers on how designs and technologies can be applied to optimizing a bearing for a particular industry or aerospace application. © 2010 Chinese Journal of Aeronautics.


Mirring P.,FAG Aerospace GmbH | Streit E.,FAG Aerospace GmbH
Proceedings - European Conference on Heat Treatment and 21st IFHTSE Congress | Year: 2014

Despite the current high level of reliability, there is a need for further development of capability of aerospace engine bearings. The ever-increasing power density requirements in aero-engines drive the need for increased system speed, temperature and load capability. Development, evaluation, and validation of new material and surface technologies appropriate for the aerospace industry demands a structured, rigorous approach. This is the only way new material technologies can be confidently and safely introduced into critical applications. For a first characterization of new materials and / or surface treatments, single component testing is appropriate. Promising results can be justified by further evaluation through sub-scale testing with standardized basic test rigs. Basic testing of this nature can establish strong statistical evidence based on established baselines over decades. Finally full scale testing in more sophisticated test rigs or full scale engines can then serve to confirm material advantages in actual operating conditions. This structured approach demonstrates the advantages achieved by combining plasma nitrided rings with silicon nitride (ceramic) rolling elements. Results from testing of both materials through these steps will demonstrate how this approach can be used to ensure flight safety. Specific details regarding the test results are presented herein. Favourable results warranted completion of the entire recommended test protocol. Full scale findings with simulated contamination conditions demonstrate a thirty times life improvement achieved through combination of these proven material technologies. The structured test protocol described helps to ensure the reliability of the concluded benefits.


Streit E.,FAG Aerospace GmbH | Mirring P.,FAG Aerospace GmbH | Brock J.,Barden Corporation
ASTM Special Technical Publication | Year: 2012

Development, evaluation, and validation of new material technologies appropriate for the aerospace industry demand a structured, rigorous approach. Only through this approach can new material technologies be confidently and safely introduced into critical applications. Characterizing materials through component testing is an appropriate first step. Successful results can justify further evaluation through subscale testing that can be accomplished with standardized basic test rigs. Basic testing of this nature can establish strong statistical evidence based on established baselines. Full scale testing in more sophisticated test rigs or full scale engines can then serve to confirm material advantages in actual operating environments. This structured approach demonstrates the advantages achieved by combining Duplex hardened M50 rings with silicon nitride (ceramic) balls. Results from testing of these materials through these steps will demonstrate how this approach can be used to ensure flight safety. Specific details regarding these tests are presented herein. Favorable results warranted completion of the entire recommended test protocol. Full scale findings with simulated contamination conditions demonstrate a thirty times life improvement achieved through the combination of these proven material technologies. The structured test protocol described helps to ensure the reliability of the concluded benefits. Copyright © 2012 by ASTM International.


High-speed jet engine ball bearings operate under challenging operating conditions, such as high speeds, loads, and temperatures. In addition, they have to meet the highest reliability standards. Thus, they require advanced materials, designs, and cooling systems. Though new materials, heat treatments, and component designs have been developed to meet these challenging requirements, the design of the raceway curvature ratio mainly follows the classical rolling bearing life theory, which is based on subsurface fatigue. But the frictional heating in the contact zone due to the phenomenon of microsliding is not considered in the design of high-speed ball bearings.This article presents the results obtained from rig testing with a state-of-the-art high-speed jet engine ball bearing with various curvature ratios on the inner and outer races. The influence of the curvature ratio on the bearing ring temperatures and the bearing power loss is demonstrated. © 2013 Copyright Taylor and Francis Group, LLC.


Grant
Agency: European Commission | Branch: H2020 | Program: CS2-IA | Phase: JTI-CS2-2015-CFP02-ENG-01-02 | Award Amount: 2.00M | Year: 2016

Conventional and Smart Bearings for Ground Test Demo The overall objective of the IBS project is to develop innovative smart bearings for an Ultra High Propulsion Efficiency (UHPE) Ground Test Demonstrator that not only meet the demo specification but also provide significant safety improvement compared to existing standards. IBS pursues an integrated approach comprising the development of sensor technologies, energy harvesting, wireless communication, data management and algorithms to monitor bearing behaviour in challenging operating conditions (e.g. high temperature, high speed and high thrust). As part of the UHPE Demonstration Project, IBS will design, develop, evaluate and test interchangeable conventional and smart bearings for the UHPE demonstrator. The bearing design will fulfil all requirements and safety standards for aerospace applications. The smart bearings will be able to deliver, in real time, information on the bearings main functional characteristics and health including temperature, axial & radial load, ball or roller or cage speed, lubrication quality, radial clearance and premise of failure on each part of the bearing.


Grant
Agency: European Commission | Branch: FP7 | Program: JTI-CS | Phase: JTI-CS-2009-1-SAGE-02-002 | Award Amount: 598.30K | Year: 2010

The ABAG (Advanced Bearings And Gears) project supports the SAGE2 project aims to demonstrate technologies for a Geared CROR (Counter-Rotating Open-Rotor) engine concept. The gearbox system requirements, transferring power from the low pressure turbine to the propellers, lead to the need of new, advanced technologies for critical components in particular bearings and their integration with the surrounding components (e.g. gears). The task and technical objectives are in particular: -Advanced planet bearing design including static and dynamic analysis considering the foreseen working conditions. - Definition of new technologies to meet the bearing life and reliability requirement under the expected operation conditions and technology development steps. - Demonstration through experimental test of bearing life and wear resistance (low contamination sensitivity) improvement of new technologies. - Demonstration through experimental tests for the applicability of the new technologies to gear materials and geometry of optimum bearing integration. The activity will be managed with a Phase & Gate approach and will include detailed technical/program documentation, including planning, drawings, design report, risk analysis, test plan and test requirements, test results and test analysis reports.


Grant
Agency: European Commission | Branch: FP7 | Program: JTI-CS | Phase: JTI-CS-2013-2-SAGE-04-025 | Award Amount: 699.81K | Year: 2014

The HIPSGEAR (scouting HIgh Performance Steels for GEARs and bearings) project supports the aims to demonstrate technologies for a Geared Turbofan (GTF) engine concept. The gearbox system requirements, transferring power from the fan to the low pressure turbine, lead to the need of new innovative high strength materials for critical components in particular bearings and their integration with the surrounding components (e.g. gears). The tasks and technical objectives are in particular: definition of new technologies to meet bearings and gears life and reliability requirements under the expected operation conditions and technology development steps; demonstration of the improvement of the new technologies through experimental tests for the bearings and gears life and wear resistance evaluation; demonstration through experimental tests for the applicability of the new technologies to gear materials to optimum bearing integration. The activity will be managed with a Phase & Gate approach and will include detailed technical / program documentation, including planning, drawings, design report, risk analysis, test plan and test requirements, test results and test analysis reports.


A bearing for a jet engine is a tribological system and has to withstand extreme operating conditions, like high loads, speeds and temperatures. This tribological system can be improved concerning limitation of use, service life and reliability with specific methods and technologies in order to reduce the system and life cycle costs. Possible approaches are: - Integration of functional features in the bearing system - Materials with a higher performance - Improved surfaces - Reduction of friction and temperature in the rolling contact - Optimization of the rolling contact surfaces through "Surface Engineering" (especially "Duplex-hardening") These solutions can only be implemented in new bearing developments through a very close collaboration between the jet engine manufacturer and FAG Aerospace GmbH & Co. KG at a very early stage of the bearing development. Only in this way the optimal benefit (regarding costs and technology) for the user occurs.

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