The invention discloses a small high-speed hydraulic oil cylinder which comprises an oil cylinder body and an oil
cylinder head connected to the oil cylinder body, wherein a cylinder tube is arranged in the oil cylinder body, a first oil hole is formed in the oil
cylinder head, a second oil hole is formed in the oil cylinder body, the first oil hole is communicated with the top of the cylinder tube, and the second oil hole is communicated with the bottom of the cylinder tube; a
piston is coaxially nested in the cylinder tube and comprises an upper end and a lower end, the
diameter of the upper end is larger than that of the lower end, the upper end is erected on a step surface at the bottom of the cylinder tube, a mounting groove is formed in the top surface of the upper end, a mounting hole is formed in the bottom surface of the lower end and communicated with the mounting groove, a valve needle is arranged in the mounting groove, one end of the valve needle is erected in the mounting groove, the other end is arranged in the mounting hole, and the upper end of the valve needle is fixed in the mounting groove through a limit block; and a snap spring is connected to the outer wall of the lower end in a sleeving manner. By means of the small high-speed
hydraulic cylinder, positions of rubber feed points of a small plastic product are closer, and when a
needle valve hot runner system is adopted, the problem that no space is reserved for accommodating the traditional oil cylinder due to overlarge
diameter can be solved with application of the cylinder.