| 摘要 |
<p>A hydraulic transmission control circuit having selector valves for communicating fluid at a first pressure to selected speed ratio clutches and for communicating fluid at a second pressure to directional clutches capable of acting as master clutches, a first modulating valve for modulating the first fluid pressure and a differential valve for establishing the second fluid pressure relative to the first fluid pressure, the control circuit also including a manually controlled modulating valve having a modulating spool which is manually operable for selectively modulating the second fluid pressure in two discreet operating modes in order to provide more precise regulation over clutch engagement under different operating conditions, the manually controlled modulating valve also including relief means for selectively reducing the first fluid pressure during regulation of the second fluid pressure by the manually controlled modulating valve.</p> |
