Patent ID: 7717132
Filing Date: 2010-05-18
Classification: F16K,Y10T

Abstract:
1. A valve-actuator for controlling a hydraulic function produced by the valve, comprising: a valve including a chamber, ports spaced mutually and opening into the chamber, a spool axially located in the chamber for opening and closing hydraulic connections between at least two of the ports as the spool moves axially in the chamber; an actuator including a housing including mutually spaced surfaces, a piezoelectric element located in the housing between the surfaces, the element expanding and contracting in response to a variable electric voltage signal applied to and the element, the spool moving axially in the chamber in response to said expansion and contraction of the element; a voltage driver including first and second terminals; an electrode electrically connected to the element, including a third terminal connected to the first terminal, and a fourth terminal connected to the second terminal; and a first resistor connected in series with the first and third terminals; and a second resistor connected in series with the second and fourth terminals.