| 摘要 |
1,020,397. Seals. CESSNA AIRCRAFT CO. Oct. 28, 1964 [Nov. 12, 1963], No. 44053/64. Heading F2B. A pressure-closed annular seal between a journal member and a journaling member which expose circumferential portions of one end of a clearance space between the members to separated zones of high and low pressure comprises an annular seal arranged in a groove in one of the members, the arrangement being such that an end wall of the groove defines, in conjunction with the adjacent member, a twosurface valve seat and fluid from a zone of high pressure forces its way between the seal and seat into the groove, travels circumferentially around the groove to a position adjacent a zone of low pressure and, in attempting to pass the seal into the zone of low pressure, closes the seal on to its seat. As applied to a vane type hydraulic motor, Fig. 5, a wedge-shaped seal 33 is made of P.T.F.E. and formed with serrations 34 on its base. In operation, fluid on the high pressure side 22 of the vane 15 leaks into the groove 31 and travels, as indicated by the arrows, circumferentially towards the low pressure side 21 where it lifts the seal on to its seat. The bearing is lubricated by the fluid which passes down the clearance 67 to a further sealing arrangement 38. In Fig. 6 (not shown) the seal 53 is lightly-pressed on its seat by a spring 55. In Fig. 7 (not shown), an 0-ring 73 under compression serves to urge the seal 68 on its seat and prevent leakage past the outer end of the journal 70. In Fig. 9 (not shown), a U-shaped seal 80 is provided, the legs of the U being directed inwardly; when high pressure fluid leaks past the face 77 it forces the seal on to its seat so as to prevent escape of the fluid into the zone of low pressure and past the outer end of the journal 76. The seal may also be applied to a Corliss type valve. |
