| 摘要 |
<p>A spool valve including a valve body having a bore intercepted by at least two axially spaced ports and a spool reciprocally received within the bore and having two axially spaced lands separated by a groove, one side wall of the groove being adjacent one of the lands and defining a shoulder. At least one shallow metering slot is disposed in the other of the lands and opens to the groove through another side wall thereof opposite from the first mentioned side wall. The slot has an increasing depth in the direction toward the groove and a cross sectional area taken transversely to the axis of the spool at any point along the slot less than the area of the top of the slot from the point to the end of the slot remote from the groove. An additional slot is disposed in the shoulder and opens to the groove, has a ramp-like bottom, and a width different from that of the metering slot.</p> |
