Hydraulic damper

The utility model discloses a hydraulic damper which comprises a working cylinder, a piston and a slidable piston rod arranged in the working cylinder, wherein the working cylinder is divided into an upper chamber and a lower chamber by the working cylinder; the piston is provided with a damping passage; the working cylinder is internally provided with a feed screw nut which is matched with the piston rod to form internal circulation type ball helical gearing; the piston comprises a piston body and a sliding block; the sliding block is arranged in the piston body and can move linearly to regulate the opening size of the damping passage during rotation of the piston body. Compared with the prior art, the hydraulic damper has the advantages that the piston rod and the feed screw nut are matched to form internal circulation type ball helical gearing so as to drive the damping plunger sliding block in the piston body to move, the damping plunger sliding block moves along the radial direction of the piston body so