Anglicky v odborných předmětech "Support of teaching technical subjects in English “

1. Anglicky v odborných předmětech"Support ofteachingtechnicalsubjects in English“ Tutorial: Physics Topic: Lubricationofengines and gearboxes Prepared by : RNDr. Ondřej Jeřábek Projekt Anglicky v odborných předmětech, CZ.1.07/1.3.09/04.0002 je spolufinancován Evropským sociálním fondem a státním rozpočtem České republiky.

2. Lubrication of engines and gearboxes

3. Lubricationofenginesandgearboxes Meaning of lubrication • Reduction of friction among movable and stationary engine parts • Preservation of combustion engines • Cooling of some parts of combustion engines • Minimisation of worn combustion engines 'parts Types of lubrication: • Forced – with a pump • By spraying – spraying of lubricant by movable parts movement

4. Lubricatingenginesystem • Oil pan • In the lowest engine or gearbox part • It is used to gather excess oil • Oil pump • Most often– internal gear pump • Filter pump • Lubricating channels • They ensure oil supply to all parts of engine or gearbox parts • Oil filter • Oil filtration • If filter is blocked, then oil is bypassed.

5. Lubricantfunction in gearbox • By contact of toothed wheels there happens: • Teeth rolling • Slipping • Slipping mostly participates in gearbox heating • High temperature can destroy toothed wheels • Meaning of gearbox lubrication: • Increasing of gear efficiency • Temperature decreasing • Gear durability • Impurities flashing off • Lubricant separates friction surfaces from each other by very thin layer • The layer must be thicker than unevenness on toothed wheels´ surface

6. Solid lubricants • Materials with very good slipping features • They are mostly used in combination with oil • Requirements for solid lubricants • Ability of attaching to at least one of contact surfaces • Chemical stability at required temperature • To be ecological • Easy application • To be economical • Examples of solid lubricants: • Graphite, PTFE, tin, gold, lead, silver

7. Relieflubricants • They are frequentlycombinationsofsoaps and oils • They are oftenused to smallindustrialgearboxes • Advantages: • They do not havestop – start effect • They solve problems of sealing working space • Theyhavewiderrangeoftemperatures • Theyseal in watertoo • Theystay on theplace • Disadvantages: • Lower removal of heat from the contact compared to oil • They are not suitableforhighspeeds • They do not cleancontactsurfaces

8. Liquidlubricants • Mixture of basic oil and additives • Basic oils are mineral or synthetic • Additive influence: • Resistance to getting old • Low-temperature feathers • Protection against corrosion • Basic oil influence: • Thermal stability • Removalofheat

9. Waysofgearboxlubrication • Dripping • Lubricant drops on lubricated surface • Bath in oil (spraying) • Oil is sprayed by movement of gearbox parts • It is not suitable for high-speed gearboxes • Circulation lubrication • See Engine lubrication • Pressure lubrication • It is lubrication by compressed air with added some quantity of oil

10. Activity I • Explain the difference between circulation lubrication and lubrication by spraying

11. Activity II • Explain main requirements for lubricating system and meaning of gearboxes´ lubrication

12. Literature • JAN, Zdeněk; ŽDÁNSKÝ, Bronislav ; ČUPERA, Jiří . Automobily 1. Brno : Avid, 2004. 211 s. • JAN, Zdeněk; ŽDÁNSKÝ, Bronislav ; ČUPERA, Jiří . Automobily 2. Brno : Avid, 2004. 120 s. • JAN, Zdeněk; ŽDÁNSKÝ, Bronislav ; ČUPERA, Jiří . Automobily 3. Brno : Avid, 2004. 220 s. • JAN, Zdeněk; ŽDÁNSKÝ, Bronislav ; ČUPERA, Jiří . Automobily 4. Brno : Avid, 2004. 350 s. Translation: • www.seznam.cz • www.slovnik.cz • JANATA, Petr. Handy slovník technický anglicko-český a česko-anglický. Plzeň: Nakladatelství Fraus, 2000. ISBN 80-7238-075-3 • Lingea LEXIKON 5, Technický slovník anglicko-český a česko-anglický. 2010.