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APPLYING HARD THIN COATINGS TO TAPPETS TO REDUCE FRICTION
Technical Paper
2001-01-1886
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
In a motorcycle engine, the tappets convert the rotating motion of the cams to the pitching motion of the valves, and they slide with the cams at a high speed under high pressure. Reducing the friction between the tappets and the cams would increase the power of the engine.
We studied a way to reduce the coefficient of friction between tappets and cams by applying a hard thin coating of DLC, MoS2, CrN, or TiN to the tappets. We investigated the adhesion of the coatings with a scratch test and their tribological properties with a ball-on-disk test. We then examined their durability with an engine stand test. We concluded that a tappet coated with DLC effectively reduces friction at the cam and tappet interface and is sufficiently durable to be applied to actual motorcycle engines.
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Kodai, A., Mori, T., and Inukai, T., "APPLYING HARD THIN COATINGS TO TAPPETS TO REDUCE FRICTION," SAE Technical Paper 2001-01-1886, 2001, https://doi.org/10.4271/2001-01-1886.Also In
References
- Scamel A.R. Grischke M. Bethke R. “Amorphous Carbon Coatings for Low Friction and Wear in Bucket Tappet Valve Trains” SAE Paper 970004
- Masuda M. Ujino M. Shimoda K. Nishida K. Marumoto I. Moriyama Y. “Development of Titanium Nitride Coated Shim for a Direct Acting OHC Engine” SAE Paper 970002
- Kodai A. Mori T. Ono H. The Japan Sciety for Heat Treatment, Proceeding of the 49th conference 1999 47
- Kodai A. Mori T. Ono H. The Japan Sciety for Heat Treatment, Proceeding of the 48th conference 1999 53