Abstract: A drill bit direct drive for deep well drilling tools includes a tubular casing, a rotary machine provided inside the casing and driven by oil well fluid flowing through it, a radially mounted shaft connected to a rotary drill bit and at least one friction bearing exposed to the oil well fluid for axial bearing of the shaft and having at least one trace ring supported on the shaft plus at least one bearing ring supported on the housing and working together with one trace ring. This bearing ring has a number of bearing segments distributed regularly around its periphery including a bearing body supported with respect to the bearing ring so it can be shifted axially and tilted to a limited extent against the action of a spring force.

Abstract: A direct drive for well drilling tools is established which includes a friction bearing with a trace ring and a bearing ring. The bearing ring has a number of bearing segments distributed around its periphery. These bearing segments are supported so that they can be tilted and shifted axially. Each bearing segment includes a support part mounted in a bore of the bearing ring and a compression spring rod arranged in the bore of the bearing ring to provide tilting and axial shifting of the segment against a spring force.

Abstract: A drive device for driving a drill bit for drilling bore holes in underground formations comprises a tubular housing for attachment to a drill string with a rotary drive means in the housing arranged to be driven by fluid forced through the housing. The rotary drive means drives an output shaft for connecting to a drill bit, the output shaft being supported by at least one axial bearing which comprises a continuous bearing ring and a retaining ring carrying a plurality of bearing segments which are swivellingly mounted to provide for a spacing of reducing cross-section between the bearing surfaces so that relative rotation of the bearing ring and bearing segments causes fluid to flow into the space and build up a hydrodynamic lubricating film.