| 摘要 |
<p>1286655 Hydrostatic transmission control HYSTER CO 25 Sept 1969 [16 Oct 1968] 47288/69 Heading F2D An hydrostatic transmission for a lift truck comprises a variable displacement axial-piston pump 14 and a similar fixed or variable motor 24, the displacement of the-pump being effected by a servo 36 controlled by a valve 52 subjected to opposed signals 54 responsive to pump delivery pressure and a spring 66 loaded by a piston 50 responsive to engine speed. The engine speed signal is derived from an enginedriven pump 16 and the piston 50 is subjected to the pump 16 pressure on opposite sides of a restriction 62. The piston is also controlled by a valve 72 which may be positioned by a vehicle brake signal 76 to provide inching control. Again, a signal 88 acts to position valve 72 to cut back the displacement of pump 14 when the hydraulic accessories are connected in by valve 84 to be powered by an engine pump 18, and the total load on the engine is excessive. The accessories are thus given priority over the vehicle drive. A pressure relief valve 90 and a reversing valve 32 are provided. Again, a reversible pump may be used.</p> |
