Power Loss in Mechanical Transmissions. Pedro M.T. Marques, Ramiro C. Martins and Jorge H.O. Seabra

Transcription

1 Power Loss in Mechanical Transmissions Pedro M.T. Marques, Ramiro C. Martins and Jorge H.O. Seabra Open day CETRIB, Porto 06 May 2016

2 Outline 1. Motivation 2. Gearbox power loss 3. Experimental investigation 4. Modelling results 5. Improve power loss 6. The importance of higher level effects 7. Conclusions 2

3 Outline 1. Motivation 2. Gearbox power loss 3. Experimental investigation 4. Modelling results 5. Improve power loss 6. The importance of higher level effects 7. Conclusions 3

4 Motivation Increasing environmental awareness has lead to: Research and development of environment friendly technological solutions: Biodegradable lubricants; Decrease energy consumption; Increased life cycle of machines and mechanisms. Lower energy consumption also helps economy! Design a transmission with power loss in mind has become a necessity: Directly reduces energetic consumption and environmental impact; Leads to lower operating temperatures, reducing lubricant oxidation and promoting longer longevity; Probability of surface distress related problems is reduced; ( ) 4

5 Motivation A gear pair is already quite efficient, usually > 97% Increasing efficiency by 1% has a small impact in overall power consumption, but there are a lot of gear transmissions out there... Nevertheless there are high power transmissions, (Eg: wind turbine gearboxes): Increasing the efficiency of a 2.5MW wind turbine gearbox by 1% represents an energy saving W!!! 5

6 Outline 1. Motivation 2. Gearbox power loss 3. Experimental investigation 4. Modelling results 5. Improve power loss 6. The importance of higher level effects 7. Conclusions 6

7 Gearbox Power Loss Gears: Churning (almost impossible to accurately model ) Frictional load loss (Usually most important component at nominal loads) Rolling bearings Seals Auxiliary (none of the previous): Usually additional churning loss. Estimating gearbox power loss is a very difficult problem 7

8 Outline 1. Motivation 2. Gearbox power loss 3. Experimental investigation 4. Modelling results 5. Improve power loss 6. The importance of higher level effects 7. Conclusions 8

9 Experimental Investigation Rolling bearings Gears Gearbox Design of efficient transmissions requires proper power loss models to accurately Estimate gearbox power loss! Models need to be experimentally validated in order to be reliable! Once properly validated models can be used confidently! No load loss 9

10 Experimental Investigation Modified 4 ball machine A lubricant is selected; Operating conditions imposed; Torque loss is measured; Boundary and Full film CoF s are obtained from experimental results! 10

11 Experimental Investigation FZG test rig A lubricant is selected; Operating conditions imposed; No load torque loss is measured; Total torque loss is measured; Rolling bearing power loss predicted using the previous results! Seals are included in the measured no-load loss! Total No-load Estimated Bearings = Gears 11

12 Experimental Investigation FZG test rig H v is the gear loss factor: Depends on the loaded geometry; μ is heavily influenced by: Lubricant; Operating conditions; Gear Geometry; XL from C40 experiments applied to H501 12

13 Experimental Investigation Real life application Measure no-load loss to find churning loss Tangential speeds, contact pressure and lubricant carefully chosen to match real life operating conditions!! No-load loss measured at the real operating temperatures and speeds! 13

14 Outline 1. Motivation 2. Gearbox power loss 3. Experimental investigation 4. Modelling results 5. Improve power loss 6. The importance of higher level effects 7. Conclusions 14

15 Modelling Results Rolling bearings Gears Gearbox No load loss Gearbox power loss estimation! 15

16 Outline 1. Motivation 2. Gearbox power loss 3. Experimental investigation 4. Modelling results 5. Improve power loss 6. The importance of higher level effects 7. Conclusions 16

17 Improve power loss How to improve gearbox power loss? At nominal operating conditions gears usually drive the power loss! Lubricant? Gear Geometry? C40 H v = H501 H v = H951 H v =

18 Improve power loss Lubricant+Gear Geometry? Power loss driven gear design + high efficiency lubricant: Can result in very significant efficiency gains! 18

19 Outline 1. Motivation 2. Gearbox power loss 3. Experimental investigation 4. Modelling results 5. Improve power loss 6. The importance of higher level effects 7. Conclusions 19

20 The importance of higher level effects Study of gear dynamics may lead to more reliable designs (dynamic overload!) Gearing cycle introduces dynamic excitations! Which modify the tooth loads and local power loss Can dynamic effects modify the estimated average power loss in a gearbox? Ongoing research at CETRIB suggests that the estimated average power loss is affected! 20

21 Outline 1. Motivation 2. Gearbox power loss 3. Experimental investigation 4. Modelling results 5. Improve power loss 6. The importance of higher level effects 7. Conclusions 21

22 Conclusions Experimental research is a fundamental step in the development of reliable models! Theoretical analysis of influencing parameters is crucial to come up with power saving, reliable and highly efficient gears! Combining experimental and theoretical knowledge can result in substantially more efficient gear designs can be achieved! Current challenges on transmissions: Polymeric gears Axle gears Hypoid gears 22

23 Acknowledgments The authors gratefully acknowledge the funding supported by National Funds through Fundação para a Ciência e a Tecnologia (FCT), under the project EXCL-II/EMS- PRO/0103/2012 and PhD Grant SFRH/BD/104791/2014. LAETA under the project UID/EMS/50022/2013. Fundo Europeu de Desenvolvimento Regional (FEDER), under the project NORTE FEDER SciTech - Science and Technology for Competitive and Sustainable Industries, cofinanced by Programa Operacional Regional do Norte (NORTE2020), without whom this work would not be possible. 23

24 Thank you for your attention 24