Self-cooling type hydraulic oil cylinder

The invention relates to the field of hydraulic oil cylinders, and discloses a self-cooling type hydraulic oil cylinder which comprises a cylinder body and a piston rod installed in the cylinder body in a penetrating and sliding mode, and further comprises a heat conduction layer installed outside the cylinder body in an embedded mode, an upper ring and a lower ring, the upper ring and the lower ring are symmetrically distributed up and down relative to the transverse center line of the heat-conducting layer; a plurality of cooling thin pipes are rotatably connected between the upper ring and the lower ring at equal angles, a water inlet pipe is connected above the cooling thin pipes in a penetrating manner, the water inlet pipe is embedded and fixed in the upper ring, a transmission pipe is connected below the cooling thin pipes in a penetrating manner, a water outlet pipe is connected to the transmission pipe in a penetrating manner, and the water outlet pipe is embedded and fixed in the lower ring; a linka