| 摘要 |
1,273,431. Hydrostatic transmission control. CESSNA AIRCRAFT CO. 6 May, 1969 [16 May, 1968], No. 22970/69. Heading F2D. [Also in Division F1] In a hydrostatic transmission comprising a pump 12 and a motor M, the motor speed is maintained constant by controlling the pump displacement in response to the flow rate as measured by Venturi 19 whose tappings 20, 21 lead to servo-piston 25. Valve 30 in its rightward position vents the left side of piston 25 to cause minimum pump displacement when the system is idle. The Venturi may be replaced by restricted orifices which can be incorporated in the lands of a reversing spool valve allowing control of speed and direction of the motor. The pump displacement in such case can be reduced to a minimum, when the spool is centralized, by admitting motor upstream pressure to one side of the servo piston or by venting the other side. |
