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  • 1.
    Andersson, Martin
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    An experimental investigation of spur gear efficiency and temperature: A comparison between ground and superfinished surfaces2017Doctoral 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.

  • 2.
    Andersson, Martin
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Churning losses and efficiency in gearboxes2014Licentiate 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.

  • 3.
    Andersson, Martin
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Björklund, Stefan
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    A study of the influence of gear surface roughness and immersion depth on gear efficiency and temperature2014In: Proceedings of the 16th Nordic Symposium on Tribology - NORDTRIB 2014, 2014, p. A 1-A 6Conference paper (Refereed)
  • 4.
    Andersson, Martin
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Sosa, Mario
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Efficiency and temperature of spray lubricated superfinished spur gearsArticle in journal (Refereed)
  • 5.
    Andersson, Martin
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Sosa, Mario
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Efficiency and temperature of spur gears using spray lubrication compared to dip lubrication2017In: Proceedings of the Institution of mechanical engineers. Part J, journal of engineering tribology, ISSN 1350-6501, E-ISSN 2041-305X, Vol. 231, no 11, p. 1390-1396Article in journal (Refereed)
    Abstract [en]

    Increased machine efficiency is a requirement in today's world and geared transmissions are no exception. A back-to-back gear test rig was used to compare dip lubrication with spray lubrication regarding gearbox efficiency, mesh efficiency, gear temperature and surface roughness. Gears lubricated at the inlet of the mesh show a lower measured temperature when compared to spray lubrication at the outlet of the mesh. Spray lubrication, when compared to dip lubrication, yields the same efficiency for both rotating directions at the tested speeds of 0.5 to 20 m/s. Spray lubrication shows a significantly higher total gearbox efficiency at higher speeds, higher measured tooth temperature and no measurable change in surface roughness.

  • 6.
    Andersson, Martin
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Sosa, Mario
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Efficiency and temperature of spur gears using spray lubrication compared to dip lubricationIn: Journal of Engineering TribologyArticle in journal (Refereed)
  • 7.
    Andersson, Martin
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Sosa, Mario
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    The effect of running-in on the efficiency of superfinished gears2016In: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 93, p. 71-77Article in journal (Refereed)
    Abstract [en]

    Reduced gear contact losses are necessary to keep operating temperatures, as well as fuel consumption low. In this work, an FZG gear test rig was used to investigate the effect of running-in on superfinished gears with respect to efficiency. This was compared to ground gears where a higher contact pressure yielded higher efficiency. No difference was found between the two running-in procedures when analysing superfinished gears. The effect of running-in on gears decreased when the initial surface roughness was reduced, which initially had an Ra, Rz and Rpk value of 0.08, 0.75 and 0.08 μm respectively. Superfinished gears showed an overall higher efficiency; however, a distinctly lower efficiency was present below 2 m/s when compared to ground gears.

  • 8.
    Andersson, Martin
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Sosa, Mario
    Sjöberg, Sören
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Effect of Assembly Errors in Back-to-Back Gear Efficiency Testing2014In: International Gear Conference 2014: 26th–28th August 2014, Lyon, Woodhead Publishing Limited, 2014, p. 784-793Conference 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.

  • 9.
    Bergseth, Ellen
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Sosa, Mario
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Andersson, Martin
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    A note on the pitting life of IQ steel versus 16MnCr5 steel in a back to back gear test rig2018Conference paper (Refereed)
    Abstract [en]

    IQ-steel is isotropic (i.e. equally strong in all directions), cleaner, and with less inclusions than 16MnCr5 regular gear steel (RS). IQ-steel is used in diesel inlets and for bearings but to date has not been used for gears. Previous studies, has shown good potential to increase the bending fatigue life of gears. The method in this study is a mechanical test procedure to determine the pitting load capacity of gear transmission lubricants, but with the focus on comparing the pitting load capacity of the two steel types IQ-steel with RS. Times to failures, photographs of the fatigue damage are presented in the study. Gear teeth from each steel type were analysed using SEM. The results, which are based on six tests in total (three IQ-steel and three RS-steel gear pairs), indicate that the IQ-steel may have at least similar surface capacity as the regular steel.

    Keywords: Pitting life, Gear, IQ-steel

  • 10.
    Bergseth, Ellen
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Sosa, Mario
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Andersson, Martin
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Investigation of pitting resistance in ultra clean IQ-Steel vs commonly used conventional steel; 158Q vs 16MnCr5: Back-to-back pitting tests2015Report (Other academic)
    Abstract [en]

    KTH Machine Design has conducted pitting tests on gears made out of two different types of steel in a standard back-to-back pitting test rig (FZG). The tested gears were produced from Ovako’s IQ-Steel in grade 158Q and compared to the behaviour of a reference steel, commonly used conventional steel in grade 16MnCr5 (reference steel, RS). The test method is a mechanical test procedure generally used to determine the pitting load capacity of gear transmission lubricants, but in this study the purpose was to compare the pitting load capacity of the two steel types. The report is based on the test procedure described in FVA – Information sheet Research Project No. 371 (Practice Relevant Pitting Test) with minor changes. Time to failure and photographs of the fatigue damages are presented in this report. One gear tooth from each steel type was analysed using SEM. The results, which are based on six tests in total (three gear pairs IQ-Steel and three RS-steel), indicate that the IQ-Steel has better surface durability than the reference steel. To better understand the mechanisms involved, further tests are suggested.

  • 11.
    Li, Xinmin
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Sosa, Mario
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Andersson, Martin
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    A study of the efficiency of spur gears made of powder metallurgy materials - ground versus super-finished surfaces2016In: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 95, no 1, p. 211-220Article in journal (Refereed)
    Abstract [en]

    Power loss is one of the main concerns in gear transmission systems. In this study a recirculating power back-to-back FZG test rig was used to investigate the efficiency of spur gears made of powder metallurgy (PM) material using two different surface manufacturing methods (ground and super-finished). The results were compared with previously presented results of standard gear material from the same test rig. The influence of the material (Wrought steel or PM) and surface roughness on the gear mesh efficiency and the total efficiency of the gearbox were analyzed in detail. The Young's modulus for PM materials is lower than for conventional gear steel. This may influence gear tooth bending and the efficiency of the gear transmission. Gear contact simulation results showed that the influence of gear tooth bending on PM gear transmission efficiency can be ignored in the FZG gear geometry. Higher surface energy combined with a smoother surface led to a lower transmission efficiency for the super-finished powder metallurgy gear combination compared to the standard gear material.

  • 12. Silvergren, Sanna
    et al.
    Olofsson, Ulf
    KTH, School of Engineering Sciences (SCI), Centres, The KTH Railway Group. KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Andersson, Martin
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Lyu, Yezhe
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi. KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Norman, Michael
    Sanchez, Gonzalo Garcia
    Sjövall, Billy
    Tu, Minghui
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Ombordmätningar av partiklar och koldioxid i X60B förarhytter2017Report (Other (popular science, discussion, etc.))
  • 13.
    Sjöberg, Sören
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi. KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Andersson, Martin
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.). KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.). KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Analysis of running-in using Stribeck curves, with application to gear meshManuscript (preprint) (Other academic)
  • 14.
    Sjöberg, Sören
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Sosa, Mario
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Andersson, Martin
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    A study of the running-in and efficiency of ground gearsManuscript (preprint) (Other academic)
  • 15.
    Sjöberg, Sören
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Sosa, Mario
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Andersson, Martin
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Analysis of efficiency of spur ground gears and the influence of running-in2016In: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 93, p. 172-181Article in journal (Refereed)
    Abstract [en]

    High-performing gear transmissions are needed to reduce CO2 emissions. In this paper an FZG gear test rig was used to investigate how two running-in loads affects the gear mesh efficiency for two different temperatures. The gear surface roughness was investigated in parallel with testing. Higher efficiency was observed for tests using a high running-in load, and for low lubricant temperatures. The running-in load had a larger effect on the mesh efficiency than temperature. The high running-in load also yielded higher gear mesh efficiency and had a larger impact on surface parameters.

  • 16.
    Sosa, Mario
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Andersson, Martin
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Effect of different bearing models on gear mesh loss and efficiencyIn: Article in journal (Refereed)
1 - 16 of 16
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