A drive unit for driving at least one component of a molding machine, includes a first support, a spindle, a drive for rotating the spindle, a second support, a nut, at least one rod arranged on the second support, and an oil-tight seal. The spindle, the second support, and the nut are arranged along the spindle inside the oil-tight space in each movement position of the second support and the nut.

An injection unit for an injection molding machine includes a cylindrical body rotatably supported in a housing interior for rotational coupling with a plasticizing screw. The cylindrical body is fixed to rotate with the plasticizing screw about an injection axis. A gear train in the housing includes a central gear mounted about, and fixed to rotate with, the cylindrical body, the central gear having an uppermost extent vertically above the injection axis and opposed first and second lateral extents on horizontally opposed sides of the injection axis. A rotary drive for powering rotation of the plasticizing screw includes a first motor having a first motor shaft rotatable about a first motor axis, the first motor axis parallel to the injection axis, the first motor axis at a first elevation below the uppermost extent of the central gear, and laterally outboard of the first lateral extent of the central gear.

An injection apparatus includes (a) a barrel; (b) a nozzle at a front end of the barrel; (c) a screw in the barrel; and (d) a drive assembly including: (i) a housing having a front end coupled to the barrel; (ii) a spindle in the housing and fixed to the screw; (iii) a first motor in the housing and having a hollow first rotor through which the spindle passes. The first rotor is coupled to the spindle for driving rotation of the screw about the axis. The drive assembly further includes (iv) a second motor in the housing axially rearward of the first motor. The second motor has a hollow second rotor through which the spindle passes. The second rotor is coupled to the spindle for translating the screw along the axis in response to rotation of the second rotor relative to the spindle.

An injection unit for an injection molding machine includes a cylindrical body rotatably supported in a housing interior for rotational coupling with a plasticizing screw. The cylindrical body is fixed to rotate with the plasticizing screw about an injection axis. A gear train in the housing includes a central gear mounted about, and fixed to rotate with, the cylindrical body, the central gear having an uppermost extent vertically above the injection axis and opposed first and second lateral extents on horizontally opposed sides of the injection axis. A rotary drive for powering rotation of the plasticizing screw includes a first motor having a first motor shaft rotatable about a first motor axis, the first motor axis parallel to the injection axis, the first motor axis at a first elevation below the uppermost extent of the central gear, and laterally outboard of the first lateral extent of the central gear.