Axial differential pressure control valve (DPCV) for controlling the differential pressure between branches of a hydraulic circuit, the following being defined for said valve: - a longitudinal axis (X-X) parallel to a direction of flow of a fluid, - an axial inlet (61;111) for a return fluid under pressure supplied from a return branch of the hydraulic circuit, - a radial inlet (63;163) for a fluid under pressure P1 supplied from a delivery branch of the same hydraulic circuit, - an axial outlet (50;150) towards the hydraulic circuit for a fluid under compensated pressure, the valve comprising - an annular body (10;110); - a tubular body (20;120;220) which is coaxially inserted inside the annular body (10;110), the end of the tubular body (20;120;220) which is axially directed to the side of the axial inlet for the return fluid of the valve having an annular disk (21;121;221); - a spring (30;130) coaxially arranged outside of the tubular body and axially kept in position by said disk (21;121;221) on the inlet side and by an abutment flange (40;140) on the outlet side; - a pipefitting (50;150) for connection to the hydraulic circuit; - a coaxial closing member (55;155) for closing an outlet aperture for exit of the fluid from the tubular body (20;120;220), arranged between the latter and the pipefitting (50;150); - a locking ring nut (80;180) which can be screwed on the outlet side onto an external thread (81;181) of the pipefitting (50;150) and acts coaxially thereon so as to sealingly close the same; - a first chamber in fluid-dynamic communication with the inlet for the return fluid under pressure supplied from the return branch; - a second chamber designed to be filled with the delivery fluid under pressure P1; - sealing separation means (70;170;221,221a) arranged between said first chamber and second chamber containing the return fluid and the delivery fluid, respectively, said separation means (70;170;221,221a) being movable axially upon activation of a thrust due to a pressure differential ΔP=P1-P2 and to the spring (30;130), characterized in that: - the closing member (55;155) is fixed and - pins (82;182) are axially arranged between the ring nut (80;180) and the abutment flange (40;140) of the spring (30;130) and pass through the pipefitting (50;150) so as to come into contact with the said abutment flange (40;140) and are designed to be displaced axially upon operation of the ring nut (80;180) independently of the fixed closing member (55;155), so as to vary the compression of the spring (30;130). - a longitudinal axis (X-X) parallel to a direction of flow of a fluid, - an axial inlet (61;111) for a return fluid under pressure supplied from a return branch of the hydraulic circuit, - a radial inlet (63;163) for a fluid under pressure P1 supplied from a delivery branch of the same hydraulic circuit, - an axial outlet (50;150) towards the hydraulic circuit for a fluid under compensated pressure, - an annular body (10;110); - a tubular body (20;120;220) which is coaxially inserted inside the annular body (10;110), the end of the tubular body (20;120;220) which is axially directed to the side of the axial inlet for the return fluid of the valve having an annular disk (21;121;221); - a spring (30;130) coaxially arranged outside of the tubular body and axially kept in position by said disk (21;121;221) on the inlet side and by an abutment flange (40;140) on the outlet side; - a pipefitting (50;150) for connection to the hydraulic circuit; - a coaxial closing member (55;155) for closing an outlet aperture for exit of the fluid from the tubular body (20;120;220), arranged between the latter and the pipefitting (50;150); - a locking ring nut (80;180) which can be screwed on the outlet side onto an external thread (81;181) of the pipefitting (50;150) and acts coaxially thereon so as to sealingly close the same; - a first chamber in fluid-dynamic communication with the inlet for the return fluid under pressure supplied from the return branch; - a second chamber designed to be filled with the delivery fluid under pressure P1; - sealing separation means (70;170;221,221a) arranged between said first chamber and second chamber containing the return fluid and the delivery fluid, respectively, said separation means (70;170;221,221a) being movable axially upon activation of a thrust due to a pressure differential ΔP=P1-P2 and to the spring (30;130), - the closing member (55;155) is fixed and - pins (82;182) are axially arranged between the ring nut (80;180) and the abutment flange (40;140) of the spring (30;130) and pass through the pipefitting (50;150) so as to come into contact with the said abutment flange (40;140) and are designed to be displaced axially upon operation of the ring nut (80;180) independently of the fixed closing member (55;155), so as to vary the compression of the spring (30;130).