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WEEK 5 Dynamics of Machinery

Explore the functionality of cam and follower systems in machinery, focusing on eccentric cams and flat-face followers. Understand the critical conditions, mechanisms, and motion analysis. Learn about displacement, velocity, acceleration, contact force, and torque components in eccentric cam systems. Study harmonic and parabolic motion with practical examples.

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WEEK 5 Dynamics of Machinery

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  1. WEEK 5Dynamics of Machinery • References • Theory of Machines and Mechanisms, J.J. Uicker, G.R.Pennock ve J.E. Shigley, 2003 Prof.Dr.Hasan ÖZTÜRK

  2. CAMS Acamis a rotating machine element which gives reciprocating or oscillating motion to another element known as follower. The cam and the follower have a line contact and constitute a higher pair. The cams are usually rotated at uniform speed by a shaft, but the follower motion is predetermined and will be according to the shape of the cam. The cam and follower is one of the simplest as well as one of the most important mechanisms found in modern machinery today. The cams are widely used for operating the inlet and exhaust valves of internal combustion engines, automatic attachment of machineries, paper cutting machines, spinning and weaving textile machineries, feed mechanism of automatic lathes etc. retaining spring Prof.Dr.Hasan ÖZTÜRK

  3. ANALYSIS OF AN ECCENTRIC CAM (a) Eccentric plate cam and flat-face follower; (b) free-body diagram ofthe follower;(c) free-body diagram of the cam. An eccentric is the name given to a circular plate cam with the cam-shaft mounted offcenter.The distance e between the renter ofthe disk and the center ofthe shaft is called theeccentricity. Prof.Dr.Hasan ÖZTÜRK

  4. Prof.Dr.Hasan ÖZTÜRK

  5. P:preload F23 is the critical condition. It must always have positive value. When F23=0, the contact islost and hence cam and follower are no longertouching each other. It means that follower isno more following the profile of the cam. It is free and floating in the air. Prof.Dr.Hasan ÖZTÜRK

  6. which can be written, through a trigonometric identity, as: Prof.Dr.Hasan ÖZTÜRK

  7. Plot ofdisplacement, velocity, acceleration, and contact force for an eccentriccam system; Jump (float) may occur (F23=0) Prof.Dr.Hasan ÖZTÜRK

  8. Graph of Torque Components and Total Cam-Shaft Torque Prof.Dr.Hasan ÖZTÜRK

  9. Prof.Dr.Hasan ÖZTÜRK

  10. Prof.Dr.Hasan ÖZTÜRK

  11. Displacement diagram and derivatives for full-rise parabolic motion. Prof.Dr.Hasan ÖZTÜRK

  12. Prof.Dr.Hasan ÖZTÜRK

  13. Displacement diagram and derivatives for full-rise parabolic motion. Prof.Dr.Hasan ÖZTÜRK

  14. Harmonic Motion: Parabolic Motion: Prof.Dr.Hasan ÖZTÜRK

  15. EXAMPLE:Parabolic Motion Prof.Dr.Hasan ÖZTÜRK

  16. The cam-contact force can be written as: Note that jump will first occur at =t=600 becausethis is the first position where F approaches zero. Prof.Dr.Hasan ÖZTÜRK

  17. Prof.Dr.Hasan ÖZTÜRK

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