Design of Manual Two-Speed Drive of Pipeline Stop Valve with Automatic Speed Switching

An industrial drive based on an eccentric planetary gear with only two internal tooth gears is proposed. Moreover, because of the use of flexible elements, automatic switching of speeds as a function of the load in the actuating element of the valve is realized. In designing such a mechanism, not only is it necessary to ensure the required strength and stiffness of the flexible elements, but their dimensions must also conform to the parameters of the toothed planetary mechanism. The length and diameter of the flexible elements are determined based on the condition that radial displacement of the movable wheel as a result of deformation of the flexible elements not exceed the gap between the surfaces of the tips of the wheel teeth when the drive is operating in the mode of direct transmission of movement from the driving to the driven member and must equal the center-to-center distance of the planetary gear when it is operating in the mode of a reduction gear. The use in the mechanism of the switching speeds of flexible rods of constant cross-section leads to a significant increase in the axial dimension of the drive. Replacing them by rods produced in the form of beams of equal resistance (or cones) reduces the axial size of the rods and of the drive as a whole. The proposed methods for the design of a two-speed drive of pipeline valves help to realize efficient design of the mechanism.