Research On Hydraulic Drive System Of 45t Horizontal Direction Drilling Machinery

Horizontal directional drilling technology is the science of installing, repairing or renewing underground pipes, ducts and cables using techniques which can minimize or eliminate the need for excavation. Due to its low production, short construction period, faint environment pollution and high working safety, this technology will be wide used in the construction of underground pipelines.The hydraulic system is a research direction of horizontal directional drilling technology. It has great influence on the performance of machinery. Several hydraulic drive systems are compared in this thesis, and a program is put forward based on "independent swiveling system and independent impelling system, variable displacement pump & variable displacement motor to adjust working speed", followed by the selection of main components. Then based on the properties of variable displacement pump and variable displacement motor, combining with the machinery's technical requirements, the matching among load, variable displacement pump, variable displacement motor and diesel engine is carried out. At last, the load circumstances of the drive unit under different geological condition are analyzed, and a dynamic simulation of the hydraulic drive system is carried out based on AMESim to get the results of the working properties of the machinery under different load conditions.The mode of speed regulation in this thesis based on the teamwork of variable displacement pump(EP control mode) and variable displacement motor(HA control mode) whose displacements changed by the hydraulic working pressure, combining with the diesel engine takes the constant power control mode can realize the speed regulation by the variable load. Its characteristic is the swiveling speed and impelling speed can be changed synchronously and proportionally. A good performance of the engine-hydraulic system can be acquired, and the power utilization ratio of engine, working efficiency and the transmission efficiency of hydraulic system are higher at the same time.