الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 294 |  |  |
| | | from | 294 | | |
Abstract
The present study was delt with the lubrication and lubriicated wear of some types of cam and follower arrangements assuming an EHL operating conditions. The analysis incorporatting the deterninations of the kinematic velocities, the minimum oil film thickness, and the load and Hertzian stress over the whole of cam lobe. A boundary/mixed lubrication transition model and a friction resistance model were adopted to predict the wear and flash tempera:ture over the cam contact.
,
The entraining velocity was revealed to have the most inflluence on the formation of the oil film thickness and inence on the wear appearance. The poor access of oil to the nose area together with the associated high Hertzian stress were found to play an important role in wear of valve gear; which was shown to be concentrated over the nose part of the cycle. A parametric study was conducted to evaluate the influence of various design variables on the operating performance, and to compare some arrangements at the base of the same lift/acceleration charactteristics. These showed that reducing the spring stiffness and increasing the cam width were impressive tools in enhancing
the operating performance.
An experimental apparatus was designed to test the wear process of a direct acting cam and tappet at various running-
in conditions. These were at low and high temperatures using
oil with and without additives, and at different surface roughhness levels. The investigations showed that boundary lubrication was the dominant regime over the nose area of the cam; with
the values of the film thickness parameter ceased to be greater than unity especially at high temperatures. The experimental investigations, using the rotary talysurf, showed a qualitative agreement between the theory and experiment. The quantitative agreement was also achieved to some extent.