Applied Mechanics and Materials Vols. 268-270

Abstract: This paper describes a new innovation design idea of mechanical clamping device based on lever force amplifier by linear motor. Based on the idea, design a series of mechanical clamping devices featuring clear logic idea. The corresponding formulas and graphic examples of output force are given of. The lever-toggle force amplifier is aimed to meet the needs of larger output force. Transform the shape of the lever to meet the processing requirements of different sizes of work-pieces.

Abstract: The application of the cam mechanism is an important field in agricultural machinery since it can realize complex mechanical movement. The wear extent and action reliability of the cam affect the performance and accuracy of the mechanism. The paper combined reliability optimal design and tribology to build a fuzzy optimization model, with minimum of the cam base circle radius and minimum of the maximum contact stress as the objective functions. Compared with conventional optimization, the cam weight was reduced by 11.7%, the stress was increased by 1.96%, and the reliability increased 0.71%. Contrast tests were designed to determine the wear extent before and after optimization. The results prove the feasibility of optimization.

Abstract: The shell is one important part of steam turbo-set condenser. Fangjiashan nuclear power project in Zhejiang Province is the domestic millions-kilowatt class PWR nuclear power plant. Its condenser shell modules have large size and heavy weight. At the same time by turbine house structure restriction, the traditional construction scheme is unable to satisfy the installation requirements. According to the condenser shell module structure characteristics and construction environment, the new construction technology such as four cranes integration operation, many times of changing hook, temporary hanging on the beam of steam turbine house, is studied and adopted. The supporting lifting frame is researched and developed. Four pieces of condenser shell modules with different hanging point size are successfully constructed. This can provide reference for the construction of similar equipment.

Abstract: In the study, a five-speed manual transmission of commercial vehicles is modeled and assembled with three-dimensional (3D) software SolidWorks. In order to analyze the kinematic and dynamic performance of the manual transmission, its 3D model is imported into the software ADAMS and the Hertz elastic contact theory is applied to calculate the contact force and deformation of the meshing gears. Finally, the speed and meshing force of the meshing gears have been obtained, which are consistent with the actual situation. This method can provide guidance for the design of the key components of the transmission, and thus can shorten the development cycle and reduce the development cost of the transmission.

Abstract: Finite element method is an important computation method for analyzing the shaft rotation system of machine tools. However, due to the structural complexity of the shaft rotation system, the result error between the finite element method and the modal testing is often large. Such error results from the difference between the finite element model and the actual system. In the present study, a finite element model of the shaft rotation system is firstly established, an experiment of modal testing is also carried out to verify the results of mathematical model. Based on the comparison of the error, then the finite element model is modified by means of optimization methods. Finally, the Campbell diagram and the critical speed diagram are calculated, and the optimization values of the stiffness of bearings are obtained. The research results indicate that this method of verifying model is accurate and efficient.

Abstract: Based on drive axle basic structure of the wheel excavator, the paper established virtual prototype simulation model and built drive axle rigid-flexible coupling multi-body dynamic simulation model. According to dynamic simulation response results, it explored the curves of flexible body changed more smoothly when it reached steady state, as gear meshing force of key parts. Initial response of flexible shaft was more violent than multi-rigid body system, and the maximum mutation value reaching about 7%, where has hysteresis phenomenon. The research can supply important theory basis for the improving of wheel excavator drive axle working performance.

Abstract: A test method for riveting assembly force, used in hub bearing unit assembly, was present in this study. Based on the test results, the influences of motion trajectory of rivet head, structure of rivet machine and feed rate of rivet head on axial force were analyzed. The corresponding improvement measures were proposed.

Abstract: According to the gear meshing theory, the tooth surface equation of orthogonal face gear is derived and the mathematical model is established. Also the model was provided for simulating the bevel gear transmission system concerning the time variant stiffness and face gears errors under static load and cyclic loads. Through the model the computerized analysis of speed, angle and acceleration of gear real tooth surface could be accomplished. Rattle as discussed under condition of different static loads and the constant cyclic loads.

Abstract: Lubricating oil transfer pump is an important function subsystem in twin-screw pump system. The friction pair between Lubrication screw and shell also is heat source of the system, not only affect the temperature field of the subsystem and the whole system, and the excessive thermal deformation itself may exist can also cause drive failure. This paper established the temperature field and thermal deformation analysis model and boundary conditions of the lubrication screw by means of Finite Element Analysis, and analyzed temperature field and thermal deformation of the lubrication screw and shell as the coefficient of convective heat transfer is 1200W/m2∙°C in the oil production process, and proved thermal deformation of the lubrication screw and shell can not affect the normal work of Lubricating oil transfer pump in the condition.

Abstract: Surface mobility is used to describe the dynamic characteristics of the power transmission over the contact area between two connected structures. Due to the complexity of structures, it is difficult to build analytical models for various structures to calculate surface mobility theoretically. Therefore, without well established theoretical model to apply, the best way is to measure the surface mobility of each structure separately to obtain its dynamic characteristics of the power transmission. This paper proposes a method to experimentally measure the surface mobility over a two-dimensional contact area subject to a uniform velocity excitation. An experimental model of a rectangular thin plate with two opposite simply-supported edges is built up to validate the method. A brass shim is used to simulate the condition of the simply-supported edge. The results show that the method of the measurement derived is practicable and the reason causing the errors of the measurement is also investigated.