| 摘要 |
<p>PURPOSE: To improve the accuracy in control of a flow rate by comprising an oscillator circuit generating a position signal in response to the inductance of a spring expandable and contractable in accompany with the reciprocating motion of a spool, and determining the incremental linear position of the spool with respect to a housing in response to a frequency of the position signal. CONSTITUTION: A spool 102 of a hydraulic directional valve 104 is reciprocatable in a valve housing 106, and centered by a pair of left and right main centering springs 112. Further a pair of left and right sub-centering springs 116 are mounted in the main centering springs 112, and similarly energize the spool 102 to its neutral position. The sub-centering springs 116 are mounted between two conductive washers 202, 204 connected to a logic device through an insulated conductor 206, and generates the position signal in response to the inductance of the spring. The logic device determines the incremental linear position of the spool in response to the frequency of this position signal.</p> |
