Hydraulic servomechanism.

摘要

A hydraulic servomechanism comprises a basic body (4) having an axial hole (9) formed therein, a stationary element (7) provided on the outer peripheral surface of the basic body at a predetermined location, a sliding element (6) fitted on the outer peripheral surface of the basic body and also fitted with the stationary element for axial sliding movement relative thereto. The sliding element cooperates with the basic body and the stationary element to define therebetween a hydraulic pressure chamber (8). A plurality of through bores (101, 103) are formed in the peripheral wall of the basic body and axially arranged at predetermined intervals for communicating between the axial hole of the basic body and the hydraulic pressure chamber. A communication hole (13) is formed in the sliding element for communicating between the through bores and the hydraulic pressure chamber. A control element (14) is axially slidably fitted in the axial hole of the basic body and formed therein with a first communication passage (15) for communicating the through bores with a hydraulic fluid supply source (19) which generates the pressure of hydraulic fluid supplied to the hydraulic pressure chamber, and a second communication passage (16) for communicating the through bores with a zone under a lower pressure. A driving device (20) changes the axial position of the control element for controlling the pressure of hydraulic pressure within the hydraulic pressure chamber, to thereby control the axial position of the sliding element.