| 摘要 |
Improvement in a hydrostatic valve assembly for use in a hydrostatic transmission, for controlling fluid transfer between a first, second and third line, wherein two of the lines define first and second pressure lines within a closed loop circuit. The valve assembly comprises a valve body having ports in communication with the three lines; a spool bore and valve spool reciprocating therewithin, having first and second end portions joined by a connecting portion, and first and second bypass orifices within the valve spool; and dampers for centering the valve spool in a neutral position. The bypass orifices utilize increased cross-sectional areas that permit the passage of substantially the full flow of the charge pump, without using a charge pump relief valve, at a low pressure drop. A hydraulic system utilizing this valve assembly and a method for increasing the transmission efficiency, in the neutral mode, are also set forth.
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