【作者】 李瀛；

【导师】 杜玉明；

【作者基本信息】 天津大学 ， 机械设计及理论， 2004， 硕士

【摘要】 本文首先简要介绍了液压拉弯机的结构、用途和原理,阐述了国内外一些液压拉弯机生产厂家的发展情况,以及优势和不足,从而提出了本课题的研究重点。然后,重点介绍了对液压拉弯机一些关键性技术和问题的研究和改进工作。通过在设计和制造阶段对液压拉弯机的改进,可以减少样机的设计费用,缩短设计周期,完善液压拉弯机的功能,实现生产的自动化。在实际研究中,本文主要在以下几个方面对液压拉弯机进行了研究与改进:针对传统物理样机的设计周期长、设计成本高、修改困难等缺陷,在液压拉弯机样机的设计中,本文采用了虚拟样机技术来设计样机,利用它的开发周期短、产品质量高、成本低以及对市场的灵活反应等优点,设计出高质量、高效益的机器。由于液压拉弯机对拉伸油缸的拉紧力有较高的要求,而在实际工作过程中,由于受到外界诸多因素的影响,拉伸油缸的拉紧力很难控制。所以在本文中采用了电液伺服系统控制拉伸油缸的拉紧力。利用电气元件的信号传递速度快,线路连接方便,易于测量,比较和校正等优点,以及液压元件的输出功率大,结构紧凑,重量轻,惯性小,反应快,适合作动力元件等优点,使拉伸油缸的输出拉力满足保持为某一恒定拉力的要求。在液压拉弯机的电气控制部分,为了提高生产效率,实现自动化生产,本文采用了可编程逻辑控制器技术(PLC),以代替原有的继电器控制。它具有逻辑控制,定时控制,计数控制,数据处理等许多功能。还有灵活通用,安全可靠,环境适应性好,使用方便,维护简单的优点。这些功能都是一般继电器控制线路难以达到的。可见,在本文中,结合了液压、控制、虚拟样机以及可编程控制器等多种技术,来对液压拉弯机的样机设计、电气控制、拉紧油缸拉紧力保持等方面进行研究和完善。它能结合以上各种技术的优点,综合提高液压拉弯机的性能。更多还原

【Abstract】 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 can<WP=4>keep 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.更多还原