Patent ID: 9574583
Date: 2017-02-21
CPC Classifications: F15B,F16H

Claim:
1. A hydraulic servo-control of a servo-controlled gearbox comprising: a plurality of hydraulic actuators having respective chambers; a storing tank containing control fluid used by the hydraulic actuators at room pressure; a hydraulic accumulator including an outer housing having an axis (X) and comprising a lateral cylindrical wall coaxial to the axis (X) and an upper wall; and a piston, which is moveable inside the outer housing so as to slide along the axis (X), said piston acting to define, inside the outer housing, a first variable-volume chamber (C a pump, which draws the control fluid from the storing tank and feeds the control fluid under pressure to the hydraulic accumulator; a number of solenoid valves, which are adapted to selectively connect the chambers of the hydraulic actuators to the storing tank and to the hydraulic accumulator; the outer housing has an upper stop element for the travel of the piston inside the outer housing, the upper stop element being provided as a shoulder coaxial to the axis (X) obtained in an inner surface of the lateral cylindrical wall of the outer housing and arranged in proximity to the upper wall; the piston is provided movable between an upper stop position defined by the upper stop element and a lower stop position defined by the lower stop element; said lower stop element including a circlip having a annular shape and a perforated plate, which is interposed in use between the circlip and the piston, and wherein the perforated plate is not provided with sealing elements and/or gaskets.