This paper addresses, by means of an elastohydrodynamic line contact analysis, the influence of circumferential surface waviness of the cam surface on the lubrication of an autornotive cam and flat faced reciprocating follower. Waviness typical of that produced by the cam grinding process, is shown to have a significant influence on predicted minimum oil film thickness, as well as the magnitude and frequency of pressure oscillafions in the oil film. Wavelengths of lambda = 0.5 - 1 mm and waviness depths of S = 1 - 2 microns on the cam surface cause significant increases in the magnitude of the predicted peak oil film pressure. In addition, the frequency of the pressure oseillations is increased by an order of magnitude, in comparison with a nominally smooth cam. These high pressure oscillations occur over a small area around the cam nose. It is probable therefore that the cam surface may suffer from accelerated fatigue wear due to such waviness. A secondary high frequency oscillatory motion of the follower relative to the cam is also predicted. This may have implications for the noise and vibration of the cam/follower assembly.
Analysis of the influence of cam surface waviness on the lubrication of an automotive cam and flat faced follower
Untersuchung des Einflusses der Welligkeit der Nockenoberfläche auf die Schmierung eines Fahrzeugnockens mit flachem Folgeglied
2001
10 Seiten, 13 Bilder, 3 Tabellen, 5 Quellen
Conference paper
English
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