| 摘要 |
1,237,562. Valves; variable speed gears. CATERPILLAR TRACTOR CO. 14 June, 1968 [14 June, 1967], No. 3980/70. Divided out of 1,237,561. Headings F2D and F2V. A variable flow device 270 comprises a bore 272 along which can slide a spool 273 having a land 273a which can successively close axially disposed radial holes 274 connecting the bore to an outlet 276, the spool having an axial bias (e.g. a spring 275) tending to keep the holes 274 open and opposed by the pressure at the inlet 278 of fluid which can pass through an axial passage 277 in the spool to the bore in the region of the holes 274, the spool 273 moving to successively close the holes 274 as the inlet pressure increases, thereby opposing fluctuations in flow. The device is disclosed as replacing a constriction in parallel with a ball valve in a hydrostatic transmission in a track laying tractor claimed in Specification 1,237,561 of identical disclosure. |
