| Engine is the core of the Motor manufacturing and any other operating power machinery. The manufacture technique level of engine parts has a crucial effect on the performance, life and reliability of the engine. Therefore, exploiting the manufacture technique of key engine parts means great to promote the development of the auto industry.The camshaft is the main part of the engine gas admeasuring and driving outfit, with complex structure, unbalanced load and the high precision. At present, the camshaft enterprises at large make use of traditional manufacturing methods, and there are many defects of the traditional camshaft processing method, which has been gradually unable to meet the requirements of modern automotive industry.Assembled camshaft method has had a rapid development since the 1980s, which makes the cams, shaft and other components be an integrative camshaft in some combining manners. Comparing with the traditional camshaft, the assembled camshaft has many merits, such as, light weight, low processing cost, reasonable material using, high efficiency, high bonding strength and good economy.As a mechanical connection method, the process feasibility of knurling connection method is proved by connecting intensity experiment. Effect factors of pressure and connecting intensity are also given full analysis in the experimental. In order to enable the process to achieve industrialization, the design of NC Assembling Machine for the Assembled Camshaft is the key. In the design process of NC assembly machine, the technology parameters can be also rational optimized.Therefore, this study is to analyze the process of connecting effect parameter of the pressure and joint intensity, and design NC Assembling Machine for the Assembled Camshaft.The researched contents are special items of tackling key problem of national science and technology "the 10th five-year plan" ,and the main work has been done as follows:1. Assembly process parameters and assembly process designIn the factors of influencing the assembling pressure, materials, the width and inner diameter of cam, the excessive quantum are analyzed. In the factors of influencing the jointing static torsional intensity, materials, the outer diameter of pipe shaft, the width of cam, the excessive quantum are analyzed. The conclusions are summarized according to these analyses that the distance of the teeth should be 1mm,the assembling pressure of the assembling machine should be 35 KN and the assembling velocity is chosen as 0.01m/s in accidence. The upper moving velocity can be adopted when the machine loads nothing.According to the properties of the knurling joint process, the structure of the CNC assembling machine for the knurling assembled camshaft should consist of welding machine framework, main transmission system, clamping gyrating system, knurling system, and Rotary feed system for cams. As for CA488 engine camshaft, the analysis for the assembling process flow is studied out, which defined the functions of above systems.2. The design of the mechanism systemWith mechanical systems design principles and full consideration of the Knurling characteristics and camshaft assembly processes, the structure of main transmission system, clamping gyrating system, knurling system and Rotary feed system has been designed. The work principle and the action flow of each system are summarized, and the structure figures are studied out. The main contents are as follows:The main transmission system affects the power of press process, in which the ball screw is chosen as transmission part, as follows the electric engine is selected. The structure of gear is designed and checked, and the caterpillar track is also rationally selected.The design of clamping gyrating system is mainly about mandrel chucks, clamping fuel tanks, gears and the servo motor.The three symmetrical structures have been adopted to the knurling system.The mainly action of Rotary feed system is clamping cam components to feed by disc rotation. Rotating disc has been installed 12 fixtures, which achieves clamping and unloading the cams through the action of feeding and baiting actuator.Framework is the support of the NC assembly machine, which requires adequate stiffness and has been designed by the characteristics of above systems. Board welding structure is adopted by the framework, which consists of the stand beam, column, soleplate, upper and lower beam.The assembly diagram of Cantalever NC Assembling Machine is plotted by Synthesizing the design of main transmission system, clamping gyrating system, knurling system, Rotary feed system and framework.3. The programming of the hydraulic pressure systemAccording to assembly machine requirements and mechanical design agencies, hydraulic system is planned. The hydraulic pressure diagram has been carried out based on the preliminary design of oil source loop, pressure control loop and speed control loop. The crawling phenomenon which affects the stability of the hydraulic system has been analyzed, so as to take full account of the relevant factors and choose the lubricants in order to eliminate the crawling phenomenon. In order to make energy-saving, the hydraulic system has been improved to reduce energy loss and enhance the efficiency.4. The programming of NC systemAssembled camshaft machine is a automated CNC machine tool, the NC system should be preliminary planned in order to achieve its automated production function after the design of mechanical system been completed. The definition of machine axis is through parameter settings on the NC machine tools and related system, which use NC system debugging process as the main line. Through the analysis of motion process, the SIEMENS802D NC system and CNC system are selected. Siemens PLC functions and programming manner are analyzed, as well the CNC system module selection, overall structure of CNC system, PLC hardware and software are all designed.Summing up the above, the knurling jointing process of the assembled camshaft is researched in this paper. According to the property of the knurling jointing process and the assembling flow of the camshaft, the mechanism system of assembling machine is designed, also the hydraulic pressure system and the NC system of the assembling machine are programmed in accidence. The Research of this paper has important meaning for ameliorating the knurling process of the assembled camshaft, improving the efficiency and precision of processing the camshaft, boosting the technique renovation of the engine industry of our country. |
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