zielsicher Englisch, Metalltechnik, Schulbuch

Work with a partner and prepare a short dialogue. There are advantages as well as disadvantages of rolling bearings over plain bearings. First, mark the advantages of a rolling bearing in green and the disadvantages in red. Then prepare a dialogue. Noise emission, not divisible, easily interchangeable, little heat development, the higher the rotational speed – means less bearing capacity, high bearing capacity at low rotational speeds, larger installation diameter, less lubricant consumption, less true running accuracy, little loss of friction because of rolling friction. Listen to Mr Puntigam talking about bearings. Then ask one of your classmates the following questions. 1. Where does the term “bearings” come from? The term “bearing” comes from the verb “to bear” meaning to carry a weight. 2. What is the main function of bearings? Bearings are machine elements that allow one part to bear or to support another part that moves. 3. How old is the earliest discovered example of a rolling bearing? Where was it found? 2000 years, (in the remains of a Roman shipyard) in Italy 4. Where are the bearings produced by Mr Puntigam’s company used? in automobiles, planes, computers and various machine tools 5. What do they have to offer? high precision and durability; the ability to rotate at high speed with a minimum of noise and vibration Write down three areas of applications of plain bearings and rolling bearings. Search the internet if you need help. Then compare your results with the class. Rolling bearings Plain bearings 1. roller skates 1. turbines 2. bicycles 2. electric motors 3. assembly lines 3. transportation rollers Work in groups of four. Prepare a short presentation on one of the following topics. Take an A3 sheet and create a poster, present it to the class. 1. Classification of bearings 2. History of bearings (listen again to Mr Puntigam) 3. Characteristics of plain bearings 4. Characteristics of rolling bearings 05 A2–B1 Could you tell me some of the advantages of rolling bearings over plain bearings? Of course … I think a big advantage is that rolling bearings are easily interchangeable. unterstrichen = advantages unterwellt = disadvantages 06 A2–B1 listening 2jh5xh 07 A2 08 A2–B1 142 Unit 27 Interaction Nur zu Prüfzwecken – Eigentum des Verlags öbv