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Effect of Assembly Errors in Back-to-Back Gear Efficiency Testing
KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.ORCID iD: 0000-0003-2489-0688
2014 (English)In: International Gear Conference 2014: 26th–28th August 2014, Lyon, Woodhead Publishing Limited, 2014, 784-793 p.Conference paper, Published paper (Refereed)
Abstract [en]

As gear efficiency is improved in small steps, it is important to be able to distinguish actual improvements from scatter that can occur while testing. An FZG back-to-back gear test rig was used to investigate how the assembly and re-assembly of the same test setup affects the measurements. A spread in loss torque between one assembly and another of the same test setup were observed. Rig conditions also affected the spread in input torque. With knowledge of how the spread in loss torque varies due to assembly, test results could be distinguished between changes due to assembly and actual differences between tests.

Place, publisher, year, edition, pages
Woodhead Publishing Limited, 2014. 784-793 p.
National Category
Tribology
Identifiers
URN: urn:nbn:se:kth:diva-152910DOI: 10.1533/9781782421955.784ISI: 000348383200079ISBN: 978-1-78242-195-5 (print)ISBN: 978-1-78242-194-8 (print)OAI: oai:DiVA.org:kth-152910DiVA: diva2:752012
Conference
International Gear Conference, August 26-28 2014, Lyon, France
Funder
Swedish Energy Agency
Note

QC 20150706

Available from: 2014-10-02 Created: 2014-10-02 Last updated: 2017-03-10Bibliographically approved
In thesis
1. Churning losses and efficiency in gearboxes
Open this publication in new window or tab >>Churning losses and efficiency in gearboxes
2014 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Efficient transmissions systems are key to producing competitive motor vehicles that have a smaller environmental impact. Gears are the main components in vehicle transmissions and although they are already highly efficient, there is still room for improvement. In this study, the focus falls on the lubricant used to create separating films between gears and todissipate heat. When driving, the gears churn this lubricant, giving rise to power losses that are related to the amount and properties of the lubricant. However, any attempt to reduce these losses must not compromise the required lubrication and heat dissipation. Paper A reports on the use of an FZG gear test rig to investigate power losses and heat generation for different gear immersion depths, surface roughness and coatings. The results show that lower gear roughness reduces gear mesh losses and heat generation. A polishing affect was obtained when a non-coated gear ran against a coated gear.The aim of the research reported in paper B was to increase the accuracy of efficiency testing. It investigated how and whether repeated disassembly and re-assembly of the same test equipment, as well as test performance and rig conditions, affect the measured torque loss in an FZG gear test rig. It was shown that the measured torque loss changes between one assembly and another. Repeatability between tests is crucial for accurate conclusions.The aim of the research reported in paper C was to study whether gear efficiency could be increased by a running-in procedure, which would reduce the need for a coolant. A back-to-back gear test rig was used to test two running-in loads. Higher gear mesh efficiency was seen when a higher running-in load was used.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2014. 22 p.
Series
TRITA-MMK, ISSN 1400-1179 ; 2014:11
Keyword
gears, efficiency, temperature, running-in, assembly, torque loss, surface roughness
National Category
Tribology
Identifiers
urn:nbn:se:kth:diva-152914 (URN)978-91-7595-277-2 (ISBN)
Presentation
2014-10-23, Sal B242, Brinellvägen 85 KTH, Stockholm, 10:00 (English)
Opponent
Supervisors
Funder
Swedish Energy Agency
Note

QC 20141006

Available from: 2014-10-06 Created: 2014-10-02 Last updated: 2014-10-06Bibliographically approved
2. An experimental investigation of spur gear efficiency and temperature: A comparison between ground and superfinished surfaces
Open this publication in new window or tab >>An experimental investigation of spur gear efficiency and temperature: A comparison between ground and superfinished surfaces
2017 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis focuses on reliability when testing gear efficiency and on how gear mesh efficiency can be increased without detrimental effects on the gears. Test equipment commonly used in gear research was analysed to identify important parameters for gear efficiency testing. The effect of the bearing model's load-dependent losses on gear mesh efficiency was also investigated. Two different surface finishes of gears, ground and superfinished, were investigated to determine how two different load levels during running-in affect gear mesh efficiency and changes in surface roughness. Efficiency and gear temperature were also measured for ground and superfinished gears with dip lubrication, as well as two different forms of spray lubrication (before and after gear mesh contact).

Tests on a gear test rig, showed that different assemblies of the same test setup can yield different measurements of torque loss. The applied bearing model had a significant effect on the estimated gear mesh efficiency. The mesh efficiency of ground gears is affected by the running-in procedure, with a higher running-in load resulting in a higher mesh efficiency than a lower load. This effect was not seen for superfinished gears, which show the same gear mesh efficiency for both running-in loads. Gearbox efficiency increased with spray lubrication rather than dip lubrication. The gear mesh efficiency increased, and thus gear temperatures were reduced, when superfinished gears were used rather than ground gears. A lower gear temperature was measured when gears were spray lubricated at the mesh inlet rather than the mesh outlet.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2017. 51 p.
Series
TRITA-MMK, ISSN 1400-1179 ; 2017:02
Keyword
gears, ground, superfinished, efficiency, temperature, running-in, dip lubrication, spray lubrication
National Category
Tribology
Research subject
Machine Design
Identifiers
urn:nbn:se:kth:diva-202990 (URN)
Public defence
2017-03-31, Gladan, Brinellvägen 85, Stockholm, 10:00 (English)
Opponent
Supervisors
Note

QC 20170314

Available from: 2017-03-14 Created: 2017-03-10 Last updated: 2017-03-14Bibliographically approved

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Sosa, MarioOlofsson, Ulf

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