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The purpose of this study is to make virtual machine using a 3D modeller to perform reverse engineering. Through the intuitive designers ability, approximated model of the object is created and used to extract the data and NC tool path. The extracted data make approximated curve by using NURBS curve fitting. And the curve is used to remodel. From these series of process, the final reverse engineering data of the objects can be obtained. Two conclusions are drawn from this study. First, initial deviation of the intuitive model is one of the important factors that determine the number of repetitions of the experiment. Due to the characteristic of intuitive curve, after a certain number of repetitions the average deviation increase and radiate rather than decrease.
Thermal flow formed by thermoelectric module type air-conditioner installed in the cabin of commercial trucks was investigated by using realizable k-ε turbulence model in the condition of incompressible, steady-state and three-dimensional numerical analysis. In consequence, the operating point of virtual fan comparatively shows high static pressure and low flowrate in each number of revolution. This means that the re-design of flow paths composing of air-conditioner is necessary for lower static pressure and larger flowrate. Anyway, the air cooling temperature difference in cabin obtained under the outdoor temperature of 40℃shows about 6∼9.7℃in the front of a driver"s seat and about 6∼9.2℃in a driver resting space at present circumstances, respectively.
In this study, The virtual machines instead of a common 3D measuring instrument was applied to the reverse engineering, it was investigated for the suitability. The virtual machine using reverse engineering, the intuitive model of the object was made by the designer"s eidetic skills and the NC data path and shape data generated from it. The extracted data were remodeled and approximation curve was made using NURBS curve fitting. From these series of process, the final revers engineering data of the objects could be gained. Four conclusions were obtained from this study. First, the appropriate degree of the NURBS curve fitting is 6 degrees which has small local errors, is stable but the equation is not that complicated. Second, when it comes to approximation of curve, the radius of the curve and the increased number of the data is in inverse proportion to approximate quantity of curve. Third, in the data extraction from NC tool path, the error occur equivalent to the tool radius according to number of tool axis and direction of tool path. And accuracy of NC is more precise, and increase in the number of extracted data. Last of all, the virtual machine could extract the shape data of the object and could remodel without 3D measuring instrument, and the revers engineering was possible with only the data of 13% level of 3D measuring instrument.
In this paper, we studied the power decision methods of driven motor for electric tractor. To decided the electric tractor power, we require to investigate the usage and working conditions of duty mode, weight, working velocity and transmission steps and so on. Usage of tractor is acquired through the investigation of user and working conditions are acquired by the measuring data of the working load. We made the measuring system using telemetry for torque, RPM, Pressure sensors and measured the data of 5 duty mode that was the drive, loader, trailer. rotary and mower. It was the engine output torque, RPM, pressure of transmission in each transmission steps and velocity. We decided the power of electric tractor through the duty analysis of measured data and weight of duty mode load. As a result, the 7Kw driven motor is decided to develop the electric tractor that alternate 17Kw engine tractor.
The rolling piston type-rotary compressor has been widely used for refrigeration and air-conditioning systems due to its compactness and high-speed operation. The present analysis is part of a research program directed toward maximizing the advantages of refrigerant compressors. The study of lubrication characteristics in the critical sliding component is essential for the design of refrigerant compressors. Therefore, experimental investigation of the lubrication characteristics of a rotary compressor used for refrigeration and air-conditioning systems was studied. In order to measure the friction force between the vane and rolling piston, an experimental apparatus known as the Pin-on-Disk was used. Load is applied by the hydraulic servo valve controlling the pressure of the hydraulic cylinder. The results showed that the rotational speed of a shaft and the discharge pressure significantly influence the friction force between the vane and the rolling piston.
In this paper, it is developed the Mono-Tube type damper with improved performance and impact resistance. The damper has feature to pressed in protector of radiation fin type. To improve the radiation characteristic, optimum radiation fin is adopted through the fin type analysis and made the damper considered characteristic of radiation and manufacturing. Developed damper is investigated in durability, radiation performance and impact resistance. It" results are compared with exist damper characteristic.
The bent-axis type piston pump which is driven by the piston rod works on the way that the piston rod drives the cylinder block, so the taper angle of the piston rod and the swivel angle between the cylinder block and the shaft are very important design factors. If the above factors cannot satisfy the conditions of optimum design, the friction loss between the cylinder bore and the piston increases, and the pump can even fail to work under conditions of severe friction and wear. Since the piston reciprocates in the cylinder bore with high velocity, and at the same time it rotates on its own axis and revolves on the center of the cylinder block, the decrease of the volume efficiency generated on account of the leakage between the cylinder bore and the piston. Therefore, to prevent this case, the piston ring is designed at the end of the piston, and the friction characteristics between the piston ring and the cylinder bore are in need of research due to its great influence on the performance of piston pump. Thus, in this paper, the elastic hydraulic oil's lubrication analyses of the film thickness, the pressure distribution, and the friction force, and so on, have been performed, and the lubrication characteristics between the piston ring and the cylinder bore are explored by the results of the numerical analysis, and it is contributed to realize the higher efficiency and the more advanced performance of the bent-axis type piston pump.
In this paper, we studied the working data measuring and analysis technology for tractor development. To measured the tractor power and performance, firstly, we investigated the usage and working conditions of tractor duty mode, weight, working velocity and transmission steps and so on. Usage of tractor is acquired through the investigation of user and working conditions are acquired by the measuring data of the working load. Secondly, we made the measuring system using telemetry for torque, RPM, Pressure sensors and measured the data of 5 duty mode that was the drive, loader, trailer. rotary and mower. It was the engine output torque, RPM, pressure of transmission in each transmission steps and velocity. We decided the performance of tractor through the analysis of measured data and weight of duty mode load.
Recently, noise and vibration by roller bearing brings trouble to pass in need to more speedy rotating and light weight, high durability in rotating system. For distinction clearly of appropriateness of roller bearing element, the effect of total system necessaries sure understanding under the motion condition. But, although roller bearing is used extensively, the related researches in this field are extremely limited. Therefore, attempts have been made to calculate film thickness, pressure distribution throughout the analysis of elastohydrodynamic lubrication, and contribute to high efficiency and performance improvement of bent-axis type piston pump throughout the close examination of lubrication characteristics between roller and inner race of roller bearing in this paper.