| 摘要 |
<p>A sealing assembly (1) for a pump shaft (2), having a metal supporting structure (3), and a sealing ring (5) in turn having a main sealing lip (9) and a secondary lip (10), which extend axially in opposite directions and define an annular cavity (12) together with a lateral surface (11) of the shaft (2). When undeformed, the diameters of the two lips (9, 10) are such as to respectively determine a predetermined amount of interference and a radial clearance with the shaft (2). The sealing ring (5) is so formed as to be deformed elastically by the interference fit between the main lip (9) and the shaft (2), so as to cause the secondary lip (10) to cooperate with the shaft with substantially no interference. The secondary lip (10) is defined between two annular sides (13, 14) converging with each other to form a sealing edge (15) towards a lateral surface of the shaft (2); and the side (14) located on the opposite side to the annular cavity (12) is defined by an oblique annular surface (16) defining in radial section an acute angle with the shaft (2) so as to receive, in use, a sufficient radial thrust to raise the secondary lip (10) slightly and allow fluid to leak into the annular cavity (12). <IMAGE></p> |
