| The development of high speed and high precision machining puts forward higher requirements to the performance index of machine tools, such as acceleration, precision and so on, which demands that the main components of machine tools must be of small weight (mass) and high stiffness. The light-weight structural design of the main components of machine tools is one of the important ways to solve the problem. With the help of computer tools and finite element softwares, digital design based on technology of structural performance analysis and structural optimization has become an inevitable trend for the light-weight structural design of machine tools’main components. Compared to traditional method of design, digital design could improve the design efficiency by a large margin, get the design period shortened and reduce the consumption of materials and energy, thus to increase the economic benefit significantly.Based on the projects of our research team, the analysis of structure characteristics and structural performances of the main components of a horizontal lathe is executed, coneptional configuration design and optimization of design parameters are completed by the aid of structural topology and size optimization and finally, the influence design parameters exerted on the performances of the saddle is studied. The follows are the details of my work in this thesis:(1) The analysis of the lathe’s structure layout and the form of junction surfaces and, the geometric structure type and characteristics of machine tools’main components are implemented. The evaluation criterions of the main components for structural design are summrized. Taking a horizontal lathe as an example, the analysis of the cutting conditions, loads and constraints of the main components are made and the loads on the junction surfaces under multiple working conditions are acquired which will provide the boundary conditions for the following structural performance analysis and topology optimization.(2) The Finite Element Model of the five main components are built and the analysis of structural performances are performed with the help of ANSYS. After that, the deformation situations under the cutting loads and the vibration performance(modal shape and inherent frequency) of the main components are studied. This will provide reference and comparison basis for the structural design and optimization of horizontal lathe’s main components. (3) The structural topology optimization of the saddle is done by aid of HyperWorks and the configuration design of the saddle’s main rib is carried out based on the optimization results. The size optimization of the design parameters of the configuration scchemes is executed and finally configuration scheme four(design scheme four or five) is chosen to be the light-weight improved design of the saddle which reduces the saddle’ weight by7%on the premise that the performances do not get worse.(4) The influence the configuration design parameters exerted on the saddle’ weight and static performance is studied and the result shows that:the span length of the side wall, the thickness of horizontal plate and the thickness of guideway-supporting wall influence the performance of the saddle most; the influence of the thickness and height of the side wall and the main rib is on the middle level; compared to the former two, the influence of the angle of side wall and the main rib’s position, circle diameter and angle is far more small. At last, curves of relationship between some of the main design parameters and the performances of the saddle were drawn.The work in this thesis may provide a reference for the structural design and improvement of the main components of machine tools. |
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