SCREW PAIR FOR SCREW-NUT ECCENTRIC TRANSMISSION Russian patent published in 2019 - IPC F16B33/00 

FIELD: machine building.

SUBSTANCE: screw pair for screw-nut eccentric transmission relates to planetary helical gears, which converts rotary motion into translational motion, and can be used in linear drives, especially in mechanisms where accurate movement and positioning are required, such as precision metal cutting machines, mechanisms for guiding optical and other instruments, gun barrels, drives of controlled valves and gate valves, etc. Screw pair comprises nut (23) with screw thread (11) and screw (20) with screw thread (26), smaller diameter than screw thread (11) of nut. Screw (20) is fitted on eccentric (17) of input shaft (4). With such a fit, the axes of the screw and nut are shifted relative to each other and can rotate relative to each other. Part of surface of screw (20) is made with cylindrical gear profile (28), which is conjugated with toothed profile (25), made on threaded surface of nut (23). In order to eliminate imbalance on same shaft (4) the second eccentric opposite eccentric (17) is made. Second screw (22) with screw thread (27) is set on this eccentric with possibility of rotation. This screw also has cylindrical toothed profile (29), which is conjugated with the same toothed profile (25) made above the thread of nut (23).

EFFECT: such design of screw pair eliminates possibility of thread turns slipping, which stabilizes pitch of axial movement of gear.

5 cl, 6 dwg