| 摘要 |
<p>A controlled sliding valve comprises a valve housing with cylindric bore, in which a slide controlling a hydraulic flow reciprocates by an adjusting force. The sealing surfaces between the slide and bore form a sealing gap converging in the flow direction, and the size of the flow is controlled between a throttling edge and longitudinal control grooves (7,8;44,45) in the slide with variable cross-sectional area in the direction of movement of the slide. A centering spring retains the slide in closing position. In order to obtain low adjusting forces, to control the volume so as to be substantially constant and independent of the pressure drop over the valve, and to maintain low leakage past the slide, the valve housing includes a central chamber (6) provided with a port (3), and on both sides of said central chamber two control chambers (9,10) with ports and each with a sealing gap (11 and, respectively, 12) spaced from each other. Either of the central chamber (6) and two control chambers (9,10) communicates in all adjustment positions with the control grooves (7.8), which can be caused to open to only one of the sealing gaps (11 or 12) at a time. The centering spring (13) acts centering for the slide from the positions of movement where there is flow connection between the central chamber (6) and either of the two control chambers (9,10), and the flow direction is in the converging direction of the sealing gaps (18,19) whereby, thus, the hydraulic flow can pass between the central chamber (6) and one of the two control chambers (9, 10) at a time in the direction determined by the sealing gaps having to converge in the flow direction. Fig. 1 to be published.</p> |
