螺栓夹紧力报告.docVIP

Summary Purpose The ISDe engine local cylinder head capscrew preload was performed to validate whether preload could meet the requirement of assembly specification (81KN±6KN). This file documented the ISDe engine local cylinder head capscrew preload measurement result. 目的 为了验证ISDe发动机国产缸盖螺栓拧紧后产生的预紧力是否满足安装规范要求(81KN±6KN)，本次试验对ISDe发动机国产缸盖螺栓预紧力进行了测试。本文件归档ISDe发动机国产缸盖螺栓预紧力测试结果。 Conclusions 1: According to assembly specification, the thread below the hex flange of cylinder head capscrew only should be lubricated .But the actual condition was that the bottom surface of hex flange was lubricated wrongly in the first group. The bottom surface of the hex flange was what was called bearing surface .It leaded the decrease of friction coefficient. So the data of the first one was unauthentic. 2：By analysing the data of preload which don’t include the data from the first one，Cpk of preload for the next five engines were 0.95, 0.98, 2.21, 1.87, and 1.89The data of the case show that the engines assembled the same local cylinder head capscrews matching local cylinder gaskets had better process capability than the ones matching imported cylinder gaskets. 3：Because the cylinder head capscrew’s bottom surface of hex flange was lubricated in the first group which didn’t match the assembly specification. So by analysing the data of preload which didn’t include the first group, the average preload was 80.475KN ，the variation of preload was between 75KN and 87KN. The preload the assembly specification. 结论 1：根据安装规范,缸盖螺栓应仅润滑六角法兰以下的螺纹区域, 但实际情况是，第一组的螺栓六角法兰下端面被错误的润滑了，六角法兰下端面即所谓的承压面，这导致了摩擦系数的降低。因此第一组的数据是不可信的。 2：通过对排除第一组份数据的预紧力数据分析，后五台发动机螺栓预紧力Cpk值分别是0.95, 0.98, 2.21, 1.87, 1.89。本例中的数据表明：装配同一种发动机国产缸盖螺栓配合国产缸垫所表现出的过程控制能力优于配合进口缸垫所表现出的过程控制能力。 3: 因为第一台发动机国产缸盖螺栓的六角法兰下端面得到润滑,这不符合安装规范，因此通过对不包含第一组的预紧力数据分析，预紧力平均值是80.475KN。预紧力在75KN和87KN之间。预紧力符合安装规范。 Actions For document 下一步行动 存档 End of Summary 1.0试验方法 由于在发动机上无法直接测量缸盖螺栓装配后的预紧力，因此采用超声波法测量缸盖螺栓伸长量，从而间接计算得到缸盖螺栓预紧力。具体步骤为： （1）先在试验室对同一批螺栓拧紧过程中的预紧力－伸长量关