Drives of Pipelines Block Valve based on the Pan Precess Gear
Nowadays in Russia and abroad the majority of hand and electric drives are based on a screw gear [1]. Despite the results achieved in the area of technology of screw gears production by leading domestic and international manufacturers and successful design arrangement of drive, the low performance coefficient of screw gears, limited load capacity and significant starting torque make a particular negative impact on the reliability of the drive when operating in low temperature conditions, and also the high specific metal content of drive represent the reasons for required development of drives based on other gear mechanisms. During the last few years a number of new constructions of block valves’ drives were developed, among which the most promising ones are the drives based on the spiroid transmission [2], the harmonic drives with intermediate rolling elements [1] (TOMZEL, SibMash, Gusar) and eccentrically cyclo gear boxes (ZAO “Technology Market”, Tomsk, Russia). In comparison with screw gear spiroid gear has a higher performance coefficient and higher load capacity and has better weight and dimensional characteristics, especially in case of steel gear wheels usage. At the same time, the relatively high sliding velocity of screw turn’s surface and wheel tooth surface in comparison with the similar relative velocities of gear and wheel teeth surfaces of cylindrical and pan gears leads to significant starting torques during the operation of manual drives of block valves in severe conditions of operation. The harmonic drives with intermediate rolling bodies and eccentrically cyclo gear boxes have high performance coefficient [1] and hence low torque strength during the multiple contacts of rolling bodies. At the same time, in addition to much more sophisticated technology of such gears production in comparison with traditional screw gears, the gear’s load capacity with intermediate rolling bodies under conditions of their significantly point contact even taking
