【作者】 刘珍来；

【导师】 陈器；

【作者基本信息】 重庆大学 ， 机械工程， 2010， 硕士

【摘要】 盾构施工法是在地面下暗挖隧洞的一种施工方法,它使用盾构机在地下掘进,在防止软基开挖面崩塌或保持开挖面稳定的同时,在机内安全地进行隧洞的开挖和衬砌作业,整个隧道一次成型。经济高速发展的今天,越来越多的工程建设单位首选盾构机来代替效率低下的传统掘进法进行隧道挖掘。作为盾构机的关键部件之一的减速器是驱动刀盘运转的唯一部件,它一边与液压马达相连,一边与驱动刀盘旋转的主轴齿轮啮合,是连接两者的枢纽,不仅起着传递运动和动力的作用,还能在发生紧急制动的情况下承受载荷冲击,其受载情况是我们相当关心的。对于土压平衡盾构机来说,来自轴向和径向的压力可以由承压隔板以及开挖室内积累的泥土进行平衡,而周向的压力主要来自于由刀盘上所受摩擦力产生的扭矩,它将通过主轴齿轮直接传递到减速器上,减速器将接受各种工况下各种扭矩的冲击,特别是在土层突变和紧急制动的情况,冲击特别明显,这就有可能造成减速器某些零件的失效,导致停机。为了避免零件失效的出现同时也是为了盾构机能适应各种条件下的土层结构,有必要对盾构机减速器进行实际载荷工况下的计算分析。本文以给定的盾构机减速器空间结构尺寸和动载荷条件下减速器各传动零部件等强度等寿命为约束,以提高盾构机减速器的承载能力为目标,对各传动零部件的参数和结构进行动态优化设计,以提高盾构机行星齿轮减速器功率传递密度和可靠性。传统的设计计算方法是解析方法,该方法只能以简化方式作粗略计算,只能得到局部的应力、位移、强度及刚度情况,通过加大安全系数的方法来保证结构的强度和刚度。而应用有限元软件进行计算能够快速、准确、直观的得到结构上各部位的应力、应变等参数的分布情况。同时,通过对盾构减速器关键零部件的有限元分析,对可进行优化的部件进行结构优化设计,在保证其强度和刚度的条件下,实现减速器的结构轻量化设计。本文的研究工作如下:1)以土压平衡盾构机减速器三级行星架为研究对象,运用ANSYS-WORKBENCH中的DesignModeler模块对其建模,然后对其进行静态仿真分析,得到了应力分布的规律,并得到了危险截面处的应力数据,同时校核出了行星架的刚性。在此基础,返回几何模型建立界面,直接对其危险截面进行修正,提高了整个行星架的承载能力。分别就5个设计变量对质量及强度和刚度的影响进行讨论,然后利用AWE-DesignXplorer模块对行星架进行拓扑优化,得出了在满足其承载能力的基础上的质量最优值(比原始质量减轻11%)以及限定了刚度条件的质量最优值。2)以土压平衡盾构机减速器三级齿轮啮合副为研究对象,采用CAXA软件辅助PRO/E建立出精确的变位传动齿轮,并运用有限元分析软件模拟其啮合状态,得出啮合副在啮合瞬间的接触应力和弯曲应力值,与传统计算方法得出的数值进行比较,并分析两种方法产生差异的原因。3)以土压平衡盾构机减速器箱体为研究对象,先通过理论分析得出其载荷,然后运用有限元软件ANSYS-WORKBENCH对其进行静态分析,将得出的最大应力值与许用应力比较得出箱体强度是满足使用要求的。在此基础上,进一步讨论了箱体轴线的偏移对齿轮啮合的影响。最后,为了保证箱体在运行时不发生共振,对箱体进行了必要的模态分析,得到箱体的前8阶固有频率和振型。本文通过对土压平衡盾构机减速器装置的关键部件进行数值仿真分析,得到一些有用的结论,为盾构机减速器的设计提供了依据,对实际工程应用具有重要意义。更多还原

【Abstract】 Shield tunneling method is a way which uses the shield machine to excavate tunnel under the ground. When it is working, it is able to prevent soft ground surface collapse or maintain excavation face stability, while, keeping the excavation and lining operations safely, then forming the tunnel once. Today, the economy developed rapidly, more and more construction units first select the shield to replace the inefficient traditional excavation method for tunneling.As one of key components of the shield, reducer is the only function parts to drive the cutter. it connected to one side with the hydraulic motor while connected another side to the spindle drive gear, which is the connection between the hub. Reducer is not only plays the role of transfer movement and power, but also impact of the load bearing in the case of an emergency braking situations, so we are very concerned about its load cases.For the earth pressure balance shield machine, the pressure from the axial and radial can be balanced by pressure diaphragm and the accumulation of soil in the excavation room, while the tangential pressure mainly from the cutter’s torque generated by friction. The torque will pass through the spindle gear to the reducer, which will bear a variety of torque impacting. Under the influence of different situations, particularly mutations in the soil and emergency braking situation, the impact is particularly evident, which may cause some parts of the reducer failure , even lead to machine down. In order to avoid those situations at the same time also to adapt shield to various soil, it is necessary to make a calculation about the shield reducer under the actual load conditions. This paper used the same intensity and life under the known reducer’s spatial structure size and dynamic load as the constraint, aimed to increase the carrying capacity of shield reducer, made an dynamic optimization about the parameters and structure of the transmission components to improve power transmission density and reliability of shield planetary gear reducer. The traditional design method is an analytical method, which can only make a rough calculation with a simplified way, and can only get local stress, displacement, strength and stiffness. It must increase the safety factor to ensure structural strength and rigidity. While we can quickly, accurately and intuitively get the global stress and strain distribution about the structure by the finite element software. Meanwhile, through the finite element analysis on key parts of the shield reducer, we do a structural optimization for the components that can be optimized .As a result; we can achieve reducer lightweight design but not change the strength and stiffness.Study of this paper is as follows:1) The three planetary gear reducer of the earth pressure balance shield is studied in this paper. We use Design Modeler module of ANSYS-WORKBENCH for its modeling, and do a static simulation analysis. So we obtained the stress distribution and the stress data of dangerous section. On the basis above, we return the geometric model and do an amendment for its dangerous section to improve the carrying capacity of the whole planet frame. Next we discuss the affection of strength and stiffness caused by the five design variables. Then we do a topology optimization on the planet frame through the use of AWE-DesignXplorer module, at last we get its optimum quality (11% less than original quality) which meet the carrying capacity, and optimum quality which meet the known stiffness condition.2) The third gear meshing pair of the earth pressure balance shield is studied. Its accuracy model is built by Pro/E software assisted by CAXA and its meshing condition is simulated by ANSYS-WORKBENCH software. Then we get its value of contact stress and bending stress on the meshing moment, which compared the value obtained by the traditional method. Finally, causes of the differences between two methods are analyzed.3) The box of the earth pressure balance shield is studied. First, we obtain its load by theoretical analysis, second we make a static analysis by use of finite element software ANSYS-WORKBENCH and obtain its maximum stress value, through compared with the maximum stress value and allowable stress, and we conclude the box strength meets the use requirements. On this basis, a further discussion about whether the offset of box axis can impact the meshing pair is made. At last, we do a necessary modal analysis and get its natural frequencies and modes of first eight orders, in order to avoid box resonance at run time.In this paper some useful conclusions are achieved by finite element analysis of key components of the earth pressure balance shield machine, which provide a basis for design of shield machine reducer and have great significance in engineering application.更多还原