Martin Andersson

69 Pages·2017·4.76 MB·English

An experimental investigation of spur gear
efficiency and temperature
Acomparisonbetweengroundandsuperfinishedsurfaces
Martin Andersson
Doctoralthesis TRITA-MMK2017:02
DepartmentofMachineDesign ISSN1400-1179
RoyalInstituteofTechnology ISRN/KTH/MMK/R-17/02-SE
SE-10044Stockholm ISBN978-91-7729-287-6
TRITA-MMK2017:02
ISSN1400-1179
ISRN/KTH/MMK/R-17/02-SE
ISBN978-91-7729-287-6
Anexperimentalinvestigationofspurgearefficiencyandtemperature
MartinAndersson
Doctoralthesis
Academic thesis, which with the approval of the Royal Institute of Technology,
willbepresentedforpublicreviewinfulfillmentoftherequirementsforaDoctor
of Engineering in Machine Design. The public review is held in Room Gladan,
Brinellvägen85,RoyalInstituteofTechnology,Stockholmon2017-03-31at10:00.
Abstract
Thisthesisfocusesonreliabilitywhentestinggearefficiencyandonhow
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 in-
vestigated. Twodifferentsurfacefinishesofgears,groundandsuperfinished,
wereinvestigatedtodeterminehowtwodifferentloadlevelsduringrunning-
in affect gear mesh efficiency and changes in surface roughness. Efficiency
andgeartemperaturewerealsomeasuredforgroundandsuperfinishedgears
with dip lubrication, as well as two different forms of spray lubrication (be-
fore and after gear mesh contact).
Testsonageartestrig,showedthatdifferentassembliesofthesametest
setup can yield different measurements of torque loss. The applied bearing
model had a significant effect on the estimated gear mesh efficiency. The
meshefficiencyofgroundgearsisaffectedbytherunning-inprocedure,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
gearmeshefficiencyforbothrunning-inloads. Gearboxefficiencyincreased
withspraylubricationratherthandiplubrication. Thegearmeshefficiency
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.
Keywords
gears, ground, superfinished, efficiency, temperature, running-in, dip lubri-
cation, spray lubrication

Sammanfattning
Denna avhandling fokuserar på tillförlitlighet i verkningsgradstester av
kugghjulochhurverkningsgradenikugghjulskontaktingreppkanökasutan
att skadliga effekter uppstår. Testutrustning vanligt förekommande vid
kuggtransmissionsforskning analyserades för att identifiera viktiga parame-
trar vid verkningsgradstester av kugghjul. Effekten av lagermodellers last-
beroende förluster på kuggkontaktens verkningsgrad studerades också. Två
olika slutbearbetningsmetoder för kugghjul, slipning och finpolering, stud-
eradesförattbestämmahurtvåolikalastnivåerunderinkörningenpåverkar
kuggkontaktens verkningsgrad och förändringen i ytfinhet. Verkningsgrad
och temperatur mättes också för slipade och finpolerade kugghjul under
doppsmörjning, liksom för två typer av spraysmörjning (innan och efter
kontaktingrepp).
Tester i en kuggrigg visade att olika testuppsättningar av samma test
kan ge olika uppmätta förlustmoment. Lagermodellen hade en tydlig in-
verkanpå den uppskattade verkningsgraden ikuggkontakten. Kuggkontak-
tens verkningsgrad för slipade kugghjul påverkas av inkörningsproceduren,
därenhögreinkörningslastresulterarienhögreverkningsgradjämförtmed
en lägre inkörningslast. Finpolerade kugghjul uppvisar inte den här effek-
ten, som visar samma verkningsgrad för de båda inkörningslasterna. Väx-
ellådans verkningsgrad var högre då spraysmörjning användes jämfört med
då växellådan doppsmörjdes. Kugghjulens verkningsgrad ökade och följak-
tligen minskade kugghjulens temperatur när finpolerade kugghjul användes
jämförtmedslipadekugghjul. Enlägretemperaturikugghjulenuppmättes
då de smörjdes innan kontaktingrepp jämfört med efter kontaktingrepp.
Nyckelord
kugghjul, slipade, finpolerade, verkningsgrad, temperatur, inkörning,
doppsmörjning, spraysmörjning
iv
Preface
The work described in this thesis was carried out at KTH Royal Institute
of Technology in Stockholm at the Department of Machine Design between
November 2011 and December 2016. I would like to thank the people in-
volvedattheSwedishEnergyAgency, Scania, ABVolvo, Vicura, theRoyal
InstituteofTechnologyandChalmersUniversityofTechnologyforinitiating
and funding this project.
I am grateful for the participation of the companies Scania, AB Volvo
and Vicura which has made me more motivated throughout my time as
a PhD student. Special thanks to M˚arten Dahlb¨ack at Scania, Lennart
JohanssonatABVolvoandUsmanAfridiatVicuraforinstructivemeetings.
I am grateful to Ulf Olofsson, my main supervisor, for giving me the
opportunity to do this work and for his guidance and help with testing and
interpretationoftheresults. Iwouldalsoliketothankmyothersupervisors
Stefan Bj¨orklund and Ulf Sellgren.
This work would not have been possible without my co-authors Mario
Sosa,S¨orenSj¨obergandXinminLi. Itwasalwaysfunandrewardingtowork
withyou. IwouldalsoliketothankthestaffandallthePhDstudentsatthe
School of Industrial Engineering and Management who have contributed to
making this a fun time in my life.
Many of the test specimens were delivered by SwePart Transmission
AB.IsincerelythankHansHanssonformakingmuchofthisworkpossible.
ThehelpfromPeterCarlsson,TomasO¨stbergandStaffanQvarnstr¨omwith
practical laboratory issues is also much appreciated.
Finally, I would like to thank my family and friends who have always
been available when needed.
Tystberga, February 2017
Martin Andersson
v

List of appended papers
Paper A
Andersson M., Sosa M., Sj¨oberg S. and Olofsson U. ”Effect of Assembly
Errors in Back-to-Back Gear Efficiency Testing”. Power Transmission En-
gineering, December, 2015.
Paper B
Sosa M., Andersson M. and Olofsson U. ”Effect of different bearing models
on gear mesh loss and efficiency”. Submitted to Tribology International.
Paper C
Sj¨oberg S., Sosa M., Andersson M. and Olofsson U. ”Analysis of efficiency
of spur ground gears and the influence of running-in”. Tribology Interna-
tional, 2016, 93: 172-181.
Paper D
Andersson M., Sosa M. and Olofsson U. ”The effect of running-in on the
efficiencyofsuperfinishedgears”. TribologyInternational,2016,93: 71-77.
Paper E
Andersson M., Sosa M. and Olofsson U. ”Efficiency and temperature of
spur gears using spray lubrication compared to dip lubrication”. Accepted
for publication, Journal of Engineering Tribology.
Paper F
Andersson M., Sosa M. and Olofsson U. ”Efficiency and temperature of
spray lubricated superfinished spur gears”. Submitted to Journal of Engi-
neering Tribology.
vii
Papers not included in the thesis
Li X., Sosa M., Andersson M. and Olofsson U. ”A study of the efficiency
of spur gears made of powder metallurgy materials–ground versus super-
finished surfaces”. Tribology International, 2016, 95: 211-220.
Andersson M., Olofsson U., Bj¨orklund S. and Sellgren U.”A study of the
influence of gear surface roughness and immersion depth on gear efficiency
and temperature”. 16th Nordic Symposium on Tribology, 2014, Denmark.
BergsethE.,SosaM.,AnderssonMandOlofssonU.”Investigationofpitting
resistanceinultracleanIQ-Steelvscommonlyusedconventionalsteel; 158Q
vs 16MnCr5: Back-to-back pitting tests”. Technical report, 2015.
viii