Key Engineering Materials Vols. 579-580

Abstract: In order to develop a device for the elderly on bed for long-term to do legs rehabilitation exercise, a small-sized magnetic hydro-cylinder without piston rod is researched. The finite element analysis software--Ansoft Maxwell and an experiment device developed by us are used to analyze and to research the magnetic coupling force performance, the effects of the arrangement of the magnet, the separation distance between the magnets and the magnet thickness on the cylinder performance. Finite element analysis and experimental results show that the cylinder wall thickness should be thinned under the premise of meeting the strength requirement, the magnets should be arranged in the reverse direction, the separation distance between the adjacent magnets should be set to 4 mm, the thickness of magnet should be set to about 10 mm. Under those conditions, the better performance of magnetic hydro-cylinder without piston rod can be gotten, and the miniaturization of the cylinder structure can be realized.

Abstract: As to the practical problems of vibration and noise of automobile transmission, this paper focuses on the gear pair of automobile transmission as the research object to realize the gear meshing analysis with the software MASTA. Through establishing the simulation model of the automobile transmission to simulate the actual load condition, the process analysis of comprehensive intelligent gear modification is carried on. Finally, the reasonable modification results indicate that the simulation analysis recurring to the professional software can obtain the modified gear of the automobile transmission more suitable to the engineering application, which will provide good guidance for the development and application of new transmission gear in the future and lay the research foundation to reduce the vibration and noise of the transmission based on the gear modification method.

Abstract: Evaluation method of assembly yield in three-dimension single-station assembly process is presented based on Number-Theoretical Net (NT-net) and 3DCS. Firstly, based on the analysis of fixture deviation affect assembly deviation under arbitrary layout, the three dimensional single-station assembly deviation model under arbitrary layout is developed. Then, the principle of generating good lattice point (GLP) based on NT-net method is introduced. Afterwards, taking fixture locating variations which are sampled using NT-net method for input vectors, the samples are substituted into assembly deviation model of dimension variation propagation in single-station assembly processes to get output vectors. The statistics for qualified sample is accomplished, after comparing output vectors with the variations of measuring points on component. Assembly yield in three-dimension single-station assembly processes is gained when qualified sample divided by total sample. Finally, a real case in sheet metal assembly is given as an example to calculate the assembly yield in three-dimension single-station assembly processes. The result is validated by 3DCS.

Abstract: Based on Virtual Numerical Control machining system (VNC), a new method of Augmented Numerical Control machining system (ANC) which aims at the realization of NC machining process simulation in real machining environment is put forward. The System inputs continuous video images of real NC processing environment through camera to identify and locate the major machining and positioning parts of real machine in the image stream. And the virtual parts of VNC will be matched to the corresponding real ones of real machining system to achieve the registration of ANC. The NC system drives the virtual machining models for processing through a real machine. On the other hand, the actual running information of CNC machine are imported into the ANC system to drive some models of process variables such as cutting force, material removal rate, chip shape, tool temperature, cutting tool wear. ANC provides the platform to integrate the geometry and physical simulation based on actual information from real CNC machining environment.

Abstract: Based on the analysis of the helical surface movement forming principle, adopted synthesized modular modeling ideas, realized the construction of a complete helical surface mathematical model consisting of three core elements, element of the general mathematical model of rotator generatrix profile, element of the general mathematical model of characteristic line and element of the general mathematical model of transformation between the cross-section coordinate system and workpiece coordinate system. Generatrix of the linear-typed contour, the arc-typed contour, the higher order equation-typed contour, and the discrete point-typed contour was investigated systematically for the model. With the synthesized modular model, if the specific profile of a helical Component is given on the cross-section, it is of convenience and ease to obtain the concrete parametric model of the helical surface, simply by changing the parameter settings through the interface to acquire any types of helical surface model, thereby increasing the efficiency of modeling and providing technical support for the precise model of the helical surface with parameterization.

Abstract: The stone bridge cutting machine is a multi-function processing machine which can saw, mill and grind. The circular saw machining is the most common processing way. This paper introduced the angle calculation method of the circular saw CNC(Computer Numerical Control) machining lines and arcs, focused on the tangential following algorithm of the circular saw, which was that the tool moved along the tangential direction of the circle or arc with the interpolated motion. Meanwhile, combining with the mechanical property of the stone bridge cutting machine, that is, the rotation angle of the C-axis was less than 360 degrees, two kinds of segmentation machining algorithms were put forward. Based on PC & motion control card, using VC++ software, the stone bridge cutting machine CNC system software was developed. By running stone bridge cutting machine CNC system and testing in the factory, the results show that the circular saw machining is stable, and can meet the requirements of the circular saw CNC cutting processing.

Abstract: As a pressure regulating component, pneumatic control valve has been widely used in control system. The stability of its performance not only concerns the control precision, but also has direct influence on the systems normal operation. Thus, a test on the valves characteristics before putting into use is rather important. According to analysis of testing requirements, this paper determined the overall program of this pneumatic measurement system, designed the gas-circuit, provided specialized software for measurement, and developed an automatic test system. The experimental data shows the system is with high precision and can satisfy the needs of valve test well.

Abstract: Elliptic family gears are commonly used in non-circular gears, which include elliptic gear, high-order gear, elliptic deformed gear and high-order deformed gear, thereinto high-order deformed gear can include the elliptic family gears through adjust its order and deformed coefficient. Because non-circular gear has different tooth profile in different position of pitch curve and there is difference in the left and right tooth profile of the same gear tooth, thus the CAD modeling of non-circular gear is difficult for these characteristics; but the precise model of non-circular gear has important significance to the realization of numerical control machining, kinematic simulation and relevant mechanical analysis. This paper deduce the corresponding pure rolling mathematical model based on the pure rolling contact theory that cylindrical gear and non-circular gear mesh in the end face, and realize the CAD modeling of non-circular straight and helical gears by letting the cylindrical gear and non-circular gear make solid geometry operation, which is suitable for pitch curve with convex and concave. The non-circular gear shaping methods with equal polar and equal arc length are simulated by setting different discrete polar angles, and the transmission ratio curve and the angular acceleration curve of driven gear are get through the kinematic simulation of gear pair, which realize the transmission performance analysis of elliptic family gear pair. The above research results can be applied to the modeling and kinematic performance analysis of other non-circular gears.

Abstract: Through discussing the working characteristics of turbodrill and structural particularity of the coupling, the feasibility of couplings series design by parameterized design method has been presented. Through taking advantage of Proe, selecting a turbodrill with diameter of 195mm as the original model, the series design and parameterized design of coupling have been achieved. This paper puts forward four design skills through analyzing the parameterized design of the coupling. The method has been developed and used in the series design of oilfield turbodrill in Yangtze university of China.

Abstract: This paper puts forward a kind of new technology for metal matrix difficult-to-machine materials based on compound energy field. The new technology combine electrochemical jet machining and abrasive jet machining technology, which obtain the high quality of processing surface and greatly improve processing efficiency. Aiming at the new technology, the experimental device of compound machining is established, a large number of process experiments are carried out. The different process parameters are studied for the influence of the machining efficiency, including the machining gap, voltage and jet pressure. The experimental results show that the compound machining can be applied to machining or polishing complex shape parts of metal matrix structure difficult-to-machine materials, so it has widely application prospects.