Research And Improvement On Secondary Hoisting Performance Of Crane

Crane is a kind of lifting equipment which is in great demand in modern engineering machinery. With the development of the construction engineering, we have also gradually improved the requirement of the performance of the mechanical equipment. Secondary hoisting falling phenomenon generally exist in the hydraulic crane work process. Impact load of the inertia weight decline significantly worsen the structure of the stress state, the cause of hydraulic impact the service life of hydraulic components. Especially in the limited installation space, must effectively prevent the secondary hoisting falling. In order to improve the crane operation safety, reliability and working efficiency, this paper takes a type truck crane as research object and the theory and simulation analysis was carried out on the hydraulic system. Finally design reasonable control scheme, in order to achieve higher performance of fine-tuning and fine control performance.This paper mainly research on the following three aspects:(1) Combining with the mechanism composition and working principle of truck crane hoisting structure and taking theoretical calculation to study the influence of system parameters on the hoisting performance.(2) Setting up a hoist hydraulic system model with AMESIM software and simulating the working condition of lifting and falling to research the dynamic characteristics of hydraulic system during secondary hoisting. Simulating the factors in order to get the influence degree of various factors respectively.(3) Bring forward an improvement in view of the original system which is add two three position two way electromagnetic valve and match the time of establishing hydraulic press and the time of opening the brake to make the opening delay time of the brake can be chosen according to the change of the load. In the working condition of falling, the brake opened directly so that the drop speed can be controlled by the balancing valve. In addition, using the constant pressure oil source to provide oil for brake which could eliminate the shocks influence for opening the brake in main oil lines. Through the modeling and simulation, the feasibility of the improved scheme is verified.