Моделирование рабочих процессов энергосберегающего гидропривода технологического оборудования лесотранспортной машины

Abstract

Workflow mechanisms of forestry cranes tower rotation are accompanied by large dynamic loads that cause sudden changes in fluid pressure in balancing and braking modes. When the rotary column stops at different positions damping of pressure of the working fluid vibration occurs due to its overflow from one chamber to another through an orifice, wherein the hydraulic energy is transformed into heat one, resulting in overheating and energy loss of fluid. Efficient are energy-saving hydropneumatic drives of column of the manipulator which are able to recover energy during transient conditions and to return some of the energy back into the system. For hydraulic manipulators with four paired hydraulic cylinders of rotation mechanism of the column one pair of cylinders is proposed to be replaced by pneumatic cylinders connected to a rotary column through the gear and toothed rack that allows you to transfer it into recovery mode of energy. A mathematical model of the boom rotation of the manipulator is developed; equations for a hydro pneumatic system recovery are made. In the model three mechanical processes are considered: the rotational movement of the column about the vertical axis of the manipulator, the forward movement of the plunger along the axis of the damper, and sway of the load relative to the attachment point on the manipulator arm. To solve the system of differential equations, computer program for the simulation of hydraulic manipulator equipped with a hydraulic damper is composed. The dependence of the restoring force of the displacement of the toothed rack is get. In the vicinity of the equilibrium position, this dependence is nearly linear over a wide range of rack movement: from about 50 to 180 mm. With significant turns of the column volume of one of the chambers of the air cylinder approaches zero value, whereby the restoring force of the module increases significantly, which helps braking of the column in the final step of rotation and influences the process of energy accumulation.