| 摘要 |
PCT No. PCT/US80/00121 Sec. 371 Date Feb. 4, 1980 Sec. 102(e) Date Feb. 4, 1980 PCT Filed Feb. 4, 1980.A variable displacement auxiliary front wheel drive system (10) is provided which includes a variable displacement fluid motor (12, 14, 16) for driving at least one vehicle wheel. The fluid motor (12, 14, 16) receives fluid under pressure from a supply source (30, 32) connected to a variable displacement pressure compensated pump which supplies fluid to a hydraulic system for the vehicle accessories. To render the variable displacement fluid motor (12, 14, 16) inoperative, a fluid control system (34, 36, 40) may be selectively operated to block fluid flow from the supply source (30, 32) to the variable displacement fluid motor (12, 14, 16) and to a pressure compensating system (44) for the fluid motor (12, 14, 16). With fluid from the supply source (30, 32) blocked, a plurality of spool valves (46, 48, 50) in the pressure compensating system (44) are drained. When the fluid control system (34, 36, 40) is activated to again permit fluid to flow from the supply source (30, 32), a delay unit insures that fluid reaches a fluid clutch (96) before the variable displacement fluid motor (12, 14, 16) is activated.
|
