... further increase in velocity. There is, however, one important difference in the lubrication mechanism operating in plain journal bearings and in gears. In the case of the journal bearings, ... bearing, 7 Rolling contact bearing, 7, 248 Rolling friction, 235, 248 Rolling of tyre, 155 Rope drive, 134 Run -in, 11 Screw jack, 105 Scuffing, 9, 1 1, 12, 278 Self-lubricating bearing, ... direction during approach, reducing to zero at the pitch point where the direction of sliding changes, and increasing again as the contact progresses through the recess action. This is shown, in a...