Research On Key Technology Of Hydraulic Pull-bending Machine

Firstly, the thesis briefly addresses the structure, the use and the principles ofhydraulic pull-bending machine. Then it introduces the state of the developmentof the domestic and foreign companies that produce hydraulic pull-bendingmachine including their preponderance and deficiency. And the research emphasisof the thesis is raised consequently. Then the thesis mainly presents the researchand the improvement on some key techniques and problems about hydraulicpull-bending machine. By improving the hydraulic pull-bending machine duringthe period of the designing and producing, we can reduce the design cost of theprototype machine, shorten the design cycle and improve its performance. Thusthe production automation could be got.From the point of practical view,the thesis will research and improve thehydraulic pull-bending machine in the several facets as follow:In term of the defect of the traditional hydraulic pull-bending machine suchas its long design period,high design cost and hard modification, the thesisdesigns prototype using the virtual prototyping technology. Therefore, themachines with high quality and efficient can be developed by making full use ofthis technique with its advantages such as short development cycle, highproduction quality, low cost and flexible reaction towards market.In general, hydraulic pull-bending machine has high requirement for thetightening force of stretching cylinder. But the tightening force of stretchingcylinder is hard to control for it is affected by a lot of factors in practice. In thisthesis, the electro-hydraulic servo system is introduced to control tightening forceof the stretching cylinder. Since there are many advantages such as high signaltransmission speed, easy circuit connection, easy to measure, compare and reviseby using electrical apparatus, as well as huge output power, compact structure,light weight, small inertia and fast response that are suitable to dynamic elementby using hydraulic system, the tensile force of the stretching cylinder output cankeep constant, thus the expectation of performance can be met.In order to improve the efficiency of productivity and achieve productionautomation, we use PLC (Programmable Logic Controller) to replace thetraditional relay control system in the part of the electrical control of hydraulicpull-bending machine. The PLC has many useful functions such as logic control,timing control, count control and data processing, and many advantages such asflexibility, universality, safety, reliability, convenience and easy maintenance.These functions and advantages are hardly implemented by common relay circuit.As mentioned above, it is obvious that the thesis integrates the techniques ofhydraulic system,control theory, virtual prototyping technology and PLC toresearch and improve on the prototyping design of the hydraulic pull-bendingmachine, electrical control, keeping the tensile force of stretching cylinder and soon. Thus, the performance of hydraulic pull-bending machine is improvedsynthetically by integrating all these advantages.