Research And Development Of Mechanical And Hydraulic System For Beam Conveyance Equipment Of Bottom Suspension Of Bridge Erecting Machine

With the development of economy and the enhancement of comprehensive national strength,China’s highway construction has developed rapidly.As an important part of highway construction,bridge construction has also developed accordingly.Especially in the past decade,the construction of long-span bridges in China has entered a most brilliant period.As a result,China’s bridge erecting machine industry has also developed rapidly,and the production of equipment has also continued to expand.At present,in the expressway construction under construction,the construction of bridges accounts for a large proportion.With more and more long-span bridges,steel box girders are becoming heavier and heavier,and equipment is needed to complete the construction of bridges.Therefore,it is very important to study new bridge erection equipment.The cantilever assembly construction method used for bridge erection this time has designed a beam bottom suspension girder transportation equipment for multiple working conditions.According to the actual working condition of the beam bottom suspension hoisting equipment of mechanical and hydraulic system design,first of all the parts of equipment of beam bottom suspension girder structure through theoretical calculation,aiming at the bottom of the beam suspension equipment hoisting equipment required mechanical structural calculation of load is analyzed,and the parts selection,hydraulic system through calculation of the test is in compliance with the indicators,Preliminarily completed the mechanical and hydraulic system design scheme of beam transport equipment hanging at the bottom of the beam.The mechanical system designed for the beam bottom suspension equipment mainly includes front and rear braking systems,suspension moving systems and plug and pull pin systems.The finite element three-dimensional model of an important part of the beam transport equipment suspended at the beam bottom is established by using ANSYS software.From the perspective of the large load required for the beam transport equipment suspended at the beam bottom,and combined with the actual working conditions,the static analysis of the key parts of the mechanical system of the equipment,such as the front and rear braking systems,the suspension moving systems and the triangular displacement slings,is carried out.By imposing reasonable constraints and bearing loads,The simulation results show that the maximum deformation of the front and rear brake systems is 0.292 mm,the maximum equivalent stress is63.697 MPa,the maximum deformation of the suspension device is 0.59 mm,the maximum equivalent stress is 122.345 MPa,the maximum deformation of the triangular displacement spreader is 1.69 mm,the maximum equivalent stress is 123.78 MPa,which is less than the allowable stress of Q345 B 245 MPa.Within the allowable deformation range of the system,the structural strength meets the requirements of bridge construction.The hydraulic system designed for the beam conveyer equipment is mainly composed of oil source pressure adjustment,push and pull cylinder control and front and rear brake control hydraulic system.In the problem of synchronous movement of two cylinders on the guide rail at the bottom of the bridge,the hydraulic control system of push-pull cylinder is proposed,and the AMESim simulation model of the hydraulic control system of push-pull cylinder is established.Based on the traditional "master-slave mode",the flow rate in the hydraulic system is controlled by studying the size of the opening and closing of the proportional flow valve.The accumulator as an auxiliary power source provides a certain flow of hydraulic oil to the driven cylinder to achieve the synchronization effect of the master and slave cylinders.The simulation results show that this hydraulic system changes the traditional synchronous hydraulic system which adopts "master-slave mode" control,such as long adjustment time,poor dynamic performance,when the flow of two proportional valves is 8 L/min,11 L/min,accumulator pressure is 128 bar,the load is 0-50 t can make the front pull cylinder and the back push cylinder reach out and withdraw at the same time.Finally,after debugging and three-step test,no-load test,load test,the bridge test,beam bottom suspension hoisting equipment to meet the design requirements,and successfully completed the steel box girder carrier,bridge is now nearing completion task,finally successfully applied in jinan city second ring western section of the Yellow River bridge on the highway project site construction.