a spindle or worm drive for adjustment devices in motor vehicles . the device is secured with a fixed spindle or a fixed toothed rack to the first of two parts which can be adjusted in relation to each other , and is provided with a gear mechanism which is connected to the second of the two parts which can be adjusted in relation to each other . the gear housing is free from backlash and is enclosed by at least one bearing shell such that it is pivotable about at least one axis . the bearing shell consisting of two bearing plates which fit into one another and which can be joined to each other after enclosure of the gear housing . the gear housing is made of plastic and is provided with a concave or convex housing part which is surrounded by a convex or concave bearing shell section made of a material which is suitable for receiving crash forces , especially a metal material .