Patent ID: 8292047

Claim:
A flow control valve for hydraulic shock absorbers of the variable damping type and which comprises: a pressure tube; a piston displaceable in the interior of the pressure tube and dividing it in a compression chamber (CC) and a traction chamber (CT) which are selectively and bi directionally communicated to each other by means of axial passages provided in the piston; a hydraulic fluid reservoir, provided with a selective bidirectional fluid communication with the compression chamber (CC); and a control valve (VC) providing a selective unidirectional fluid communication, with a variable section, between the traction chamber (CT) and the reservoir, said control valve (VC) being characterized in that it comprises: a tubular body externally attached to the pressure tube ( 10 ) and comprising a regulating chamber (CR) provided with an inlet opening maintained in fluid communication with the traction chamber (CT), an outlet chamber (CS) maintained in fluid communication with the reservoir by at least one outlet orifice, a control orifice communicating the regulating chamber (CR) and the outlet chamber (CS) to each other, and a guide means coaxial to the control orifice; a shutter pin having a rod portion and a shutter portion with a cross section varying along at least part of a longitudinal extension of said shutter portion, said rod portion and shutter portion being jointly, selectively and axially displaceable in the guide means and in the interior of the control orifice, respectively, between a closing position of the control orifice and a plurality of open positions of the latter, in each of said positions the shutter portion forming, with the control orifice, a respective annular section for the passage of the hydraulic fluid to the reservoir; and an actuator means (A) operatively associated with the shutter pin in order to axially displace it, in the interior of the control orifice, to said closing and opening positions of the control orifice.