Bench Top Screening of Wet Clutch Materials S.J. Shaffer, Ph.D. steven.shaffer@bruker.com Steve Papanicolaou Steve.papanicolaou@Bruker.com TRIBODAYS 2015 October 6-7, 2015 Nynashamn, Sweden Luleå University of Technology in association with the Swedish Tribology Group and hosted by Nynas AB

Background Smooth wet clutch operation tied to velocity Full scale tests currently done on SAE No.2 type friction machines/JASOM348 Increasing demand for higher torque capacities at reduced sizes Harshness, vibration and noise (HVN) strongly tied to V dependence of COF SAE No.2 Friction machines are the first analysis step in material development program 11/15/2018 Bruker Confidential

SAE No.2 Friction test machine and Sample Typical sample size 133mm/99mm Clutch disc photo courtesy of Par Marklund, Doctoral Thesis, “Wet Clutch Tribological performance optimization methods” Lulea Univ of Technology 2008 11/15/2018 Bruker Confidential

Why do we need a valid bench top test? ROI Discussion What does it cost to buy an SAE No.2 Friction machine? $400K to $800K What does it cost to run the machine? What does it cost to make the SAE No.2 Samples? Production down time costs? Production personnel costs? How long does it take to set up an SAE No.2 Test? ~2 Hours SAE No.2 Friction machine downtime/maintenance? Researchers that run these tests at a third party spend ~$1,200/test 11/15/2018 Bruker Confidential

Defining the Tribotest What are the important parameters ? Materials Contact Geometry Loading Motion Environment 11/15/2018 Bruker Confidential

Materials and Contact Geometry Benchtop Tester Sample to be of same material of interest Contact Geometry Flat Ring on Flat, Scaled Down 133 mm Dia. 29 mm Dia. 11/15/2018 Bruker Confidential

Non Homogenous Nature (Material and Geometry Features) Size Effect Concerns Minimum Contact Size Non Homogenous Nature (Material and Geometry Features) Ra=9.09mm Ra=12.88mm Ra=3.11mm 11/15/2018 Bruker Confidential

Loading, Motion and Environment J3.3 Calls for Max Pressure of 2.96MPa 2.96Mpa on Benchtop Sample = 750N Load Max Speed on J3.3 calls for 235 RPM Equivalent Linear Velocity on Benchtop Sample = 1237 RPM Temperature steps of 40C, 90C and 120C can be achieved on benchtop system, per standard Constantly recirculating ATF 11/15/2018 Bruker Confidential

Bench Top System Bruker UMT-TL (TriboLab) 11/15/2018 Bruker Confidential

Bench Top System Bruker UMT-TL (TriboLab) Self Leveling Upper Sample Holder Torque Sensor Load Cell Lower Sample Holder ATF Supply ATF Return Peristaltic Pump ATF Supply Port Heating Chamber/Rotary Drive 11/15/2018 Bruker Confidential

Bench Top System Bruker UMT-TL (TriboLab) 11/15/2018 Bruker Confidential

Results 11/15/2018 Bruker Confidential

Results 11/15/2018 Bruker Confidential

Observations Agreement Very Good In Relative rankings Curve Shape Magnitude of COF for each material 11/15/2018 Bruker Confidential

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11/15/2018 Bruker Confidential