GB172955A - Improvements in thrust bearings and like machine elements - Google Patents

Abstract

172,955. Michell Bearings, Ltd., (Assignees of Michell, A. G. M.). Dec. 15, 1920, [Convention date]. Thrust bearings.-To obtain pressure-film lubrication in thrust bearings, screw-and-nut gearing, &c., the coacting surfaces are made of slightly different curvatures so as to form tapering interspaces, one of said surfaces being generated by a line nearly but not exactly at right-angles to the axis of rotation. Fig. 1 shows the application to a simple thrust block. The thrust collar 1 is slightly convex and bears against stationary plane shoes 3 mounted on a block 5 seated spherically in a frame 4, the shoes being retained by a ring 6. The upper surface of the block 5 is slightly concave, corresponding to the surface of the collar 1. If motion is in one direction only, portions of the working surfaces of the blocks may be removed at the leaving ends. In a modification the shoes are supported on a circular rib formed on the block 5. Fig. 8 shows the invention applied to a screw-and-nut mechanism. The screw 10 has two threads 11, 12, the lines of intersection of the working surfaces of the threads with an axial plane being slightly inclined so that these surfaces have a slight convexity. The nut 13 has internal threads 15 having the same inclination as the threads 11, 12 and having similar helical surfaces, and is formed in valves. Blocks 3, supported on the threads 15, are cut from a helical strip 14, Fig. 10, which has a smaller inclination than the threads and a working surface 14<a> either square to the axis or having a smaller inclination thereto than the surface of the threads, so that the screw-thread and blocks have coacting surfaces of differing curvatures. The strip 14 may have a rib 14<c> on its lower surface. Pins 16, Fig. 11, are inserted in holes in the threads 15 to prevent motion of the blocks, and spacing-members 17, which may be integral with the blocks, are inserted between the blocks.