The invention discloses a single-cylinder multi-point
hot runner system, which is characterized in that a cavity is formed in a cylinder body, and an annular
piston is arranged in the cavity; the annular
piston is in sliding fit with the inner wall of an accommodating cavity and divides the accommodating cavity into an upper annular
air cavity and a lower annular
air cavity which are sealed respectively; an end cover is arranged at the opening of the cavity and is in sealed connection with the inner wall of the cavity; hot runners which are communicated with one another are arranged in a flowdividing plate, and the flow dividing plate is arranged below the cylinder body; a feeding
nozzle is connected with the flow dividing plate, and an internal runner of the feeding
nozzle is communicated with an inlet of each
hot runner; a plurality of needle valves are arranged, each
needle valve comprises a valve body and a valve needle; the upper end of the valve body is connected with the flow dividing plate, an internal runner of the valve body is communicated with the
hot runner, and the valve bodies are uniformly arranged around the central axis of the annular
piston; the upper end of thevalve needle is connected with the annular piston, and the lower end is inserted into the valve body; the lower end of the
needle valve is connected with a pouring gate of the mold, and the valve needle is used for controlling opening and closing of the
needle valve. According to the invention, the opening and closing of the needle valves can be synchronously controlled, so that the
dynamic balance performance of an injection molding product is enabled to be higher.