Parker-Hannifin Corporation
Proportional Valve Spool with Linear Flow Gain

Abstract:

An example spool includes a shaft varying in diameter along a length of the shaft, and a plurality of annular lands formed on the shaft and spaced-apart by respective reduced diameter annular neck portions. The plurality of annular lands comprise at least one annular metering land, and wherein the at least one annular metering land comprises: one or more sine notches formed as a portion of a sine wave, and one or more additional notches having a different shape from the one or more sine notches.