加工偏差对连杆小头油孔疲劳安全性影响研究  

Influence of Machining Quality of Connecting Rod Small End Oil Hole on Its Fatigue Safety Coefficient

作　　者：张翼[1] 刘晓勇[1] 石志勇 苏铁熊[1] 

机构地区：[1]中北大学机械与动力工程学院,太原030051 [2]北方通用动力集团公司,大同037036

出　　处：《内燃机工程》2014年第3期52-56,共5页Chinese Internal Combustion Engine Engineering

基　　金：部委项目(61314603)

摘　　要：为了探讨连杆小头油孔的加工偏差对连杆安全性的影响程度,根据实际加工过程中出现的误差情况预设了小头油孔的加工偏差值,并建立了几何模型,采用有限元分析方法计算了不同加工偏差状态下连杆的应力大小和分布趋势,采用临界面法获取了各个位置的正应力,基于Goodman疲劳极限线图法得到了连杆小头油孔不同加工偏差状态下的最小安全系数。结果表明:对于优质合金钢材料,加工表面粗糙度由Ra3.2提升到Ra8.0,其疲劳安全系数下降10.3%,油孔倒圆从R2到无,其疲劳安全系数下降9.0%,因此保证小头油孔加工精度对连杆的可靠性至关重要。To investigate effect of connecting rod small end oil hole machining deviation on fatigue safety coefficient, firstly setting values of the oil hole machining deviation according to the practical production process, a geometrical model was constructed and used to compute stress and its distribution in the connecting rod under different machining deviations based on the finite element modem （FEM）, the normal stress in each position and the minimum safety coefficient of the connecting rod under different machining deviations were obtained by critical plane approach and Goodman fatigue limit diagram, separately. It is revealed that for the connecting rod made of quality alloy steel, its fatigue safety coefficient is greatly affected by machining quality of small end oil hole. The fatigue safety coefficient decreases by 10.3% with the surface rough- ness increasing from Ra3.2 to Ra 8.0, and by 9.0% with the oil hole outlet rounding radius decreasing from 2 mm to 0.

关 键 词：内燃机 连杆油孔 加工偏差 临界面法 疲劳安全系数 

分 类 号：TK423.32[动力工程及工程热物理—动力机械及工程]