1、Analysis based on the ANSYS metal gears and plastic gears inherent vibration characteristics compared 姓名： 班级： Abstract: Using ANSYS software gear finite element model, modal analysis, the plastic gear gun and steel gear module .State of natural frequencies and mode shapes diagram, were analyzed. The
2、 conclusion for the dynamic design of gears and gear structure related equipment fault diagnosis Off basis. Key words: plastic gear steel gear gun modal analysis of vibration characteristics 0 Introduction The gear drive is the most important in the mechanical transmission drive gear transmission be
3、cause of its high efficiency, compact structure, the transmission ratio stable and are widely used in engineering. Accelerated due to the development of high-performance engineering plastics, the proportion of the application process for plastic and steel, plastics in the field of mechanical enginee
4、ring is increasing, the production of gear materials are no longer limited to metallic materials, has grown to the plastic gear. On the application and theoretical study of the plastic gears, and steel gear, late research time is also shorter, and domestic and foreign researchers on the understandin
5、g of the plastic gear performance and application very immature, but to imitate and improve on the basis of the steel gear. Therefore, the experimental study of plastic gear is necessary. Plastic material with Bo, the elastic energy, and thus has obvious noise reduction and vibration damping perform
6、ance. In fact, for the transmission of power in terms of gear when the gear bodys natural frequencies and the frequency of exciting force is very close to the even drill the plastic material gear also have a resonance and noise 2 4321-437A. Therefore, during the plastic gear design, the vibration ch
7、aracteristics of the study is necessary. We use ANSYS software to gear finite element model, modal analysis, mode shapes and natural frequency of the plastic gears and alloy gear to provide a basis for the structural design and optimization of gear. 1 A gear modal analysis Modal analysis is used to
8、determine the natural frequency of the vibration characteristics of structures or machine parts in the design and mode shapes. Withstand dynamic bearing load structure design parameters 3 4321-4324. Finite element analysis software ANSYS, modal analysis is a linear analysis of prestressed structure
9、and cyclic symmetry structure modal analysis, modal analysis process is divided into four steps: modeling, loading and solving, extended modal and results post-processing. 1.1 gear finite element model ANSYS provides three kinds of ways: to generate a model generation method with ANSYS to create sol
10、id model, the model established by the input model system. The direct generation method suitable for small, simple model, the leaders of the other systems if the model is not suitable for meshing, requires a lot of repair work. Gear model is relatively complex, suitable for solid modeling method. Kn
11、own by the finite element theory, the solid model can not be directly used for finite element calculation, so take it mesh to generate a finite element model, the mesh will directly affect the accuracy of the finite element calculation results . Define the element type for the Structural solid Brick
12、 2 ( node 95, the input gear parameters, create the key points, connecting key points generated gear contour, gear tooth surface generated by the contour, surface generation bodies drag along the segment, showing a single tooth geometric mode J, division of a single tooth mesh gear is the structure
13、of the body of the loop extension cycle to generate the finite element model of the plastic gears in Figure 1 shows, the finite element model of the number of nodes on a single tooth 3f tS8 . unit number 1994. 1.2 gear finite element model of the mold State analysis Modal analysis of ANSYS, you must
14、 specify the elastic modulus EX. ANSYS11.0 seven kinds of modal extraction method: the Block Ianczoe (block, t the sos France), Subspace is (subspace method) IowerDvnamics (source of power law), Reduced (reduction method), Un2symmetric (non-symmetric France), the Dam Network (damping France), QRDam
15、network (Qlt damping method). In this article to Block lanczos method to extract modal. Gear model is built, its modal analysis, modal analysis of the gear. Purpose is to find the order natural frequency of the gear and its corresponding vibration mode, and therefore does not need to load, only degr
16、ees of freedom constraints. Constraints: the gear inner hole circle cylinder constraint: s:. Set of modal extraction method for the Block Canczos France, set up to extract the number of modes of 5 want to get the unit to solve the results need to open the calculate elem re-salts, the frequency range
17、 specified modal extraction 0 100 000, specify the mode state extraction method, ANSYS automatically select the appropriate equation solver. Figure 1 gear finite element model Solve the calculations are complete, view the solution results. Modal analysis results in order to get the whole gear model,
18、 the modal expansion, extended for solving the advantages of each order, for the obtained natural frequency. Solving r its corresponding mode shape is reflected in the natural frequency of each node of the gear relative displacement and relative stress conditions. Set the mode of state expansion, ex
19、tended frequency range 0 100 000. Again into the solver to calculate and view the solution results, including the natural frequency, r, has been extended modes and the corresponding relative) il, power distribution 2 Define the material properties 2.1 Structure of alloy steel Alloy steel with high s
20、trength, high toughness, wear resistance, corrosion resistance, low temperature, high temperature, non-magnetic and other special properties. Used to produce withstand dynamic load and heavy load of automobile transmission gear and car rear axle gear commonly used in power transmission, and high reliability of mechanical equipment in the 2.2 engineering materials. Engineering materials, plastic is characterized by: (1) self-lubrication, lubrication operation when necessary； (2) to reduce noise； light weight with excellent
