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根据大量的调查研究发现,有80%的发动机气缸体的变形量超出公差技术要求范围,尤以大中型拖拉机更为突出,有些机体的变形量是相当大的(包括一些新机体)。气缸体变形后,相互位置精度被破坏,严重影响了总成各组件之间的相互位置关系。实践证明,如果发动机机体变形超限,那么即使各总装的零件都是合格的新件,也会使组装后的发动机功率低、油耗高、寿命短,甚至会在短时间内发生“烧瓦”、“拉缸”等事故。例如:一台东方红-75拖拉机更换新缸体后,投入机耕作业不到2个小时,就发生了“烧瓦”事故。拆检后,发现气缸体主轴承座孔同轴度过大(为0.21毫米),同轴度过大是产生“烧瓦”的主要原因,而同轴度又是由于气缸体严重变形引
According to a large number of surveys and studies, it is found that 80% of the engine cylinder body deformation exceeds the tolerance technical requirements, especially large and medium-sized tractors are more prominent, and some body deformation is considerable (including some new body). Cylinder block deformation, the mutual position accuracy is destroyed, seriously affecting the assembly of the mutual relationship between the components. Practice has proved that if the engine body deformation overrun, even if the assembly of the parts are qualified new pieces, but also make the engine after the assembly of low power consumption, high fuel consumption, short life expectancy, or even happen in a short time “, ” Pull cylinder “and other accidents. For example: a Dongfanghong -75 tractor to replace the new cylinder, put into tillage operations in less than 2 hours, the occurrence of ”burning tile“ accident. After disassembling, it was found that the coaxiality of the main bearing hole of the cylinder block was too large (0.21 mm). The excessive coaxiality was the main reason for the ”bush burn", and the concentricity was due to the severe deformation of the cylinder block lead