Abstract: Injection unit for an injection molding machine to process material, comprising a plasticizing cylinder, a screw, and a screw drive including two electric motors, such that the two motors have an electrically controlled connection to one another, to implement an injection and metering process, such that the two motors can be operated in the same or opposite direction of rotation and with the same or different rotational speed. A space is formed by at least two sleeves which can move relative to one another, and by respectively adjoining plate members, so as to take up lubricating oil, such that the sleeves can slide into one another, and the junctions of the parts which form the space are constructed tight against the environment, at least for lubricants.

Abstract: A method is provided for operating an injection unit of an injection molding machine for metering or injecting material, also to create a back pressure in the melt, or to create a holding pressure on the melt, by means of a screw drive including two electric motors, with a controlled electrical connection to one another, and by means of a spindle-nut combination, such that the two electric motors can be operated in the same direction of rotation or in the opposite direction of rotation. In one embodiment, the two electric motors are operated counter-rotationally to inject the material, or the two electric motors are operated synchronously in their direction of rotation to create a back pressure in the melt or a holding pressure on the melt, a difference rpm being set by means of at least one electric feedback signal.