1. september 24th 20041/27 Modelling Slip- and Creep-mode Shift Speed Characteristics of a Pushbelt Type CVT Bram Bonsen, Tim Klaassen, Koen van de Meerakker, Bram Veenhuizen, Maarten Steinbuch

2. september 24th 20042/27 Project goal Optimize a pushbelt-type CVT to maximize efficiency by changing the actuation system

3. september 24th 20043/27 Slip & Efficiency

4. september 24th 20044/27 Slip & Friction

5. september 24th 20045/27 CVT actuation changes Reduction of actuation losses by: –Lowering clamping force –Using alternative actuation methods

6. september 24th 20046/27 Modeling variator What is the expected –Efficiency –Needed actuation forces –Transient response

7. september 24th 20047/27 Existing models Either –Too complex –Did not describe the effects of slip and its influence on the actuation system

8. september 24th 20048/27 Transient models Ide Shafai Simplified

9. september 24th 20049/27 Transient models Ide –Good description of transient behavior when not in slip-mode Shafai –Good description of transient behavior when in slip-mode

10. september 24th 200410/27 Combination Ide when in creep-mode shifting Shafai when in slip-mode shifting

11. september 24th 200411/27 Friction / Slip Friction force opposite to slip direction Tangential slip vs Radial slip Torque transmissionvs Shifting

12. september 24th 200412/27 Testrig

13. september 24th 200413/27 Measurements

14. september 24th 200414/27 Measurements

15. september 24th 200415/27 Measurements

16. september 24th 200416/27 Friction model Coulomb friction model: Microslip=stiction= creepmode Macroslip=sliding= slipmode

17. september 24th 200417/27 Microslip shifting mechanism Shifting and torque transmission not related Belt only partially slipping Shifting by elastic deformation of the pulleys Shifting behavior dependent on primary speed

18. september 24th 200418/27 Macroslip shifting mechanism Slip in both tangential and radial direction Shift speed primary speed independent Shift speed limited by actuation system only

19. september 24th 200419/27 Model Sliding when force >= friction, Stick when force < friction

20. september 24th 200420/27 Friction calculation

21. september 24th 200421/27 Friction calculation Friction Direction

22. september 24th 200422/27 Identification Minimize output error Number of Parameters limited to 4

23. september 24th 200423/27 Identification results Very high pulley mass found –Oil in pipes Simplified Ide model used to reduce number of parameters

24. september 24th 200424/27 Results

25. september 24th 200425/27 Results

26. september 24th 200426/27 Conclusions Combined model is more in agreement with the measurements Possibility to investigate more efficient actuation system based on slip

27. september 24th 200427/27 Recommendations Identification on different transmissions Slip while shifting is incorporated in this model. This can be used to make the actuation more efficient. Optimize the transmission based on the given parameters. (stiffness, length and thickness of pipes, place of actuators etc)