Abstract: A device for a rotary drive of a crane, a working platform, a tracking photovoltaic assembly, a heliostat, or the like, for tracking mirrors of a solar thermal power station, etc., on a foundation or chassis, of a heavy duty vehicle, or another part of a machine, comprising a worm gear having a housing having a connecting surface for connecting to a part of a machine or facility, chassis, or a foundation, with a rotatable worm, and a worm wheel rotatably mounted in the housing, wherein there is provided a rolling contact bearing on each side of toothing of the worm wheel engaged with the worm, and a connecting surface for connecting to a part of a machine or facility, to a chassis or a foundation The housing and the worm wheel each formed in one piece, wherein the smallest internal diameter of the housing is larger than the largest external diameter of the worm wheel.