| 摘要 |
<p>In a rotary coupling, such as the coupling between a piston pin and the holes for the same bored in the bosses of a piston for an internal combustion engine, a device for improving the lubrication, comprising a number of turns of capillary circumferential groove hollowed in one of the coupling surfaces, said groove having preferably a depth ranging from 5 to 20 mu m, a pitch ranging from 0.25 to 1 mm and an eccentricity not exceeding 2 mu m.</p> |
