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بسم الله الرحمن الرحيم. Tribodesign. إعداد الدكتور محمد حسن الكومي. Introduction to the Cocept of Tribology. Tribology is defined as the science and technology of interacting surfaces in relative motion, having its origin in the Greek word tribos meaning rubbing. . It is the study of:
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بسم الله الرحمن الرحيم • Tribodesign • إعداد • الدكتور محمد حسن الكومي
Introduction to the Cocept of Tribology
Tribology is defined as the science and technology of interacting surfaces in relative motion, having its origin in the Greek word tribos meaning rubbing.
It is the study of: • Friction • wear • Lubrication • In any machine there are lots of component parts that operate by rubbing together (bearings, gears, cams, tires, brakes, piston ring …etc)
Tribology finds applications in all industrial sectors including; • Aerospace • Automotive • Construction • Biomedical • Textile • Optical • Mining • Petrochemical
Friction “Friction is the resistance to motion during sliding or rolling experienced when one solid body moves tangentially over another with which it is in contact. The resistive tangential force, which acts in a direction directly opposite to the direction of motion, is called the friction force”.
Friction due to adhesion Friction due to ploughing Friction due to deformation
Sometimes it is desirable to have low friction, to save energy, or high friction, as in the following cases.
Handle End with ball thrust bearing End with nut
m mc Load on nut W Thread friction Lead rm Mean thread radius rc Collar friction Mean collar radius
Ball Screws Have Low Friction Recirculating balls roll between ball screw and ball nut to minimize friction. These almost always overhaul.
3 2 4 1 No 4 Piston No 3 Piston No 2 Piston No 1 Piston Rear Bearing Support Bearing Support Bearing Support Bearing Support Front Bearing Support