Plastic injection molding machine with rotary and linear drives

A plastics injection molding machine having a screw which is arranged in an injection cylinder and is moved by a linear drive and a rotary drive such that it is driven by only one motor. The driving motor is a servo motor and the linear drive is a piston-cylinder unit which is moved by a hydraulic pump which is connected with the driving motor and is in a closed hydraulic circuit. The screw has a drive shaft which is acted upon by the rotary drive connected to the driving motor. The rotary drive has a hydraulic drive with a motor which has a driven motor shaft corresponding to a piston rod. The motor is connected with the forward-flow line via a feed line and an outlet line. A releasable check valve, which is controllable by a two-way directional control valve, is provided in the forward-flow line.