构架安全裕度K值分析及抽检方法研究

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Analysis of Frame Safety Margin K and Study on Sampling Inspection Method

TANGZhijun，WANGHaihua

（CRRC Nanjing Puzhen Rolling Stock Co.，Ltd.，Nanjing 21oo31，China）

Abstract：At present，the three-coordinate measuring instrument is used in the processing dimension inspection of railway passenger car frames.Due to the limitation of the three-coordinate measuring instrument，it is necessary to combine sampling inspection to ensure the accuracy of the inspection. However， due to the poor data stabilityof some items inthe framework，thereis inevitablya risk of missing unqualified items in the process of random inspection，which will have a certain impact on the normal operation of vehicles. Based on the process capability index Cp and Cpk ，this paper puts forward the risk assessment method of safety margin coefficient K and the human intervention method of risk item.Combined with examples，this paper analyzes the reason for the insufficient process capability，proposes the optimization measures to improve data stability，the sampling inspection plan，and sampling inspection precautions for frameworks. The study indicates that the risk assessment method of safety margin coefficient K can reduce the three-coordinate inspection frequency of frames，improve the eficiency of frame inspection by 3 to5 times， and reduce the inspection cost. The human intervention method of risk items can change the index state of items with poor stability，make the improved sample data follow the standard normal distribution and converge，and reduce the risk of missed inspection.

Key words： three-coordinate inspection of frames； process capability index; process capability evaluation assessment method of safety margin coefficient K ；sampling inspection method of frames

构架是铁路客车转向架系统走行部关键部件之一，是铁路客车转向架系统的骨架，其加工尺寸关系到车辆在轨道线路上运行的安全性。（剩余7165字）