Influence of Catenary Profile on Lubrication Characteristics of Conrod Big-end Bearing
-
摘要: 针对柴油机连杆大头轴承润滑不良和摩擦磨损的问题,结合轴承型线的设计理论,建立了悬链型线的数学表达式。运用AVL POWER UNIT搭建连杆柔性多体动力学模型,研究了连杆大头轴承的悬链线型线对其润滑特性的影响。结果表明:当连杆大头轴承采用悬链线型线轴瓦时,随着型线径向变化量的逐步增加,峰值油膜压力先减小后增大,最小油膜厚度先增大后减小,总摩擦功耗先减小后增大。当采用径向变化量为方案4(变化量6 μm)的悬链线型线轴瓦时,最小油膜厚度增加了0.22 μm,峰值油膜压力减少了10.92 MPa,总摩擦功耗减少了0.28 kW,有利于减小轴承的摩擦磨损功耗和改善连杆大头轴承的总体润滑性能。通过曲线拟合分析得到了最小油膜厚度、峰值油膜压力和总摩擦功耗这3个评价参数的函数关系,为连杆大头轴承润滑特性的优化设计提供参考依据。Abstract: Because of poor lubrication and friction and wear of the conrodbig-end bearing of a diesel engine, based on the design theory of bearing profile, the mathematical expression of catenary profile is established. Using the AVL power unit that builds a flexible multi-body dynamics model of the conrod, the influence of the catenary profile of the conrod big-end bearing on its lubrication characteristics was analyzed. The calculation results show that: when the radial variation of thecatenary profile gradually increases, the peak oil film pressure first decreases and then increases, the minimum oil film thickness first increases and then decreases, and the total friction power loss first decreases and then increases. When the catenary bushing with the radial variation of option 4 (variation 6 μm) is adopted, the minimum oil film thickness increases by 0.22 μm, the peak oil film pressure is reduced by 10.92 MPa, and the total frictional power loss is reduced by 0.28 kW, thus being useful toreduce the friction and wear power consumption of the conrod big-end bearing and to improve its overall lubrication performance. Through curve fitting analysis, the function relationship of the three evaluation parameters of minimum oil film thickness, peak oil film pressure and total friction power loss is obtained, providing a reference for the optimal design of lubrication characteristics of the conrod big-end bearing.
-
表 1 不同径向变化量对应变参
径向变化量y/μm 轴承宽度x/mm 悬链型线变参a 2 ±12.5 39062.50 4 ±12.5 19531.25 6 ±12.5 13020.83 8 ±12.5 9765.63 10 ±12.5 7812.50 表 2 连杆大头轴承结构参数与工作参数
参数 数值 轴承宽度/mm 25 轴承孔径/mm 56 轴承半径间隙/mm 0.03 润滑油类型 5W-30 供油压力/bar 4 穴蚀压力/bar 0.98 环境压力/bar 1 轴颈表面粗糙度/μm 0.4 轴瓦表面粗糙度/μm 0.8 表 3 不同径向变化量轴承润滑参数对比
方案 径向变化
量/μm最小油膜
厚度/μm峰值油膜
压力/MPa总摩擦
功耗/kW1 0 1.25 222.19 1.14 2 2 1.32 218.84 1.01 3 4 1.39 215.77 0.91 4 6 1.47 211.27 0.86 5 8 1.18 227.19 1.23 6 10 1.12 233.49 1.29 表 4 不同函数的系数取值表
系数 f1(x) f2(x) f3(x) a0 1.28 222.4 1.08 a1 −9.53×10−2 4.50 0.13 b1 1.23×10−1 −8.74 −0.17 a2 5.09×10−2 −3.44 −0.05 b2 −4.69×10−4 0.04 −4.93×10−3 a3 −1.59×10−2 0.28 0.02 b3 9.61×10−3 −0.79 −4.90×10−3 a4 1.80×10−2 −1.02 −1.74×10−2 b4 4.12×10−3 0.39 −1.42×10−2 w 5.14×10−1 0.49 0.53 -
[1] 刘宽伟. 考虑混合润滑的连杆小头衬套松动仿真研究[D]. 北京: 北京理工大学, 2015LIU K W. Simulation research on the loosening of connecting rod small end bush considering mixed lubrication[D]. Beijing: Beijing Institute of Technology, 2015 (in Chinese) [2] 赵志强, 王根全, 王延荣, 等. 8V柴油机连杆小头轴承润滑及结构对比分析[J]. 车用发动机, 2017(2): 78-82 doi: 10.3969/j.issn.1001-2222.2017.02.014ZHAO Z Q, WANG G Q, WANG Y R, et al. Comparison of lubrication and structure for connecting rod small end bearing for an 8V diesel engine[J]. Vehicle Engine, 2017(2): 78-82 (in Chinese) doi: 10.3969/j.issn.1001-2222.2017.02.014 [3] RAZAVYKIA A, DELPRETE C, BALDISSERA P. Numerical study of power loss and lubrication of connecting rod big-end[J]. Lubricants, 2019, 7(6): 47 doi: 10.3390/lubricants7060047 [4] 黄粉莲, 彭继银, 毕玉华, 等. 非道路两缸柴油机轴承热弹性流体动力润滑特性研究[J]. 润滑与密封, 2019, 44(10): 57-64, +70 doi: 10.3969/j.issn.0254-0150.2019.10.009HUANG F L, PENG J Y, BI Y H, et al. A study of bearing thermal elastohydrodynamic lubrication characteristics for non-road diesel engine[J]. Lubrication Engineering, 2019, 44(10): 57-64, +70 (in Chinese) doi: 10.3969/j.issn.0254-0150.2019.10.009 [5] 聂涛, 刘振明, 刘楠, 等. 内燃机径向滑动轴承润滑特性及影响因素研究[J]. 计算机仿真, 2019, 36(1): 263-267 doi: 10.3969/j.issn.1006-9348.2019.01.055NIE T, LIU Z M, LIU N, et al. Research on the lubrication characteristics and influencing factors of the journal bearing in internal combustion engine[J]. Computer Simulation, 2019, 36(1): 263-267 (in Chinese) doi: 10.3969/j.issn.1006-9348.2019.01.055 [6] 毕凤荣, 刘博, 刘春朝, 等. 基于热弹流模型的柴油机连杆小头轴承润滑研究[J]. 内燃机工程, 2018, 39(4): 15-22BI F R, LIU B, LIU C C, et al. Research on diesel engine connecting rod small end bearing lubrication based on thermal elastic hydrodynamic model[J]. Chinese Internal Combustion Engine Engineering, 2018, 39(4): 15-22 (in Chinese) [7] 高真超. 某高速汽油机曲轴轴承润滑性能分析与改进[D]. 重庆: 重庆大学, 2017GAO Z C. Analysis and improvement on lubrication performance of crankshaft bearing of a high speed gasoline engine[D]. Chongqing: Chongqing University, 2017 (in Chinese) [8] 秦作鲲, 向建华, 钟乘龙, 等. 连杆小头衬套型线对其摩擦副润滑和变形特性的影响[J]. 内燃机工程, 2020, 41(1): 70-79QIN Z K, XIANG J H, ZHONG C L, et al. Effect of connecting rod small end bushing profiles on lubrication and deformation of their friction pairs[J]. Chinese Internal Combustion Engine Engineering, 2020, 41(1): 70-79 (in Chinese) [9] 阮登芳, 陈黎, 高真超. 轴瓦轮廓修形对发动机连杆轴承磨损性能的影响[J]. 中国机械工程, 2019, 30(10): 1207-1211, +1218 doi: 10.3969/j.issn.1004-132X.2019.10.010RUAN D F, CHEN L, GAO Z C. Effects of shell profile modification of engine conrod bearings on lubrication characteristics[J]. China Mechanical Engineering, 2019, 30(10): 1207-1211, +1218 (in Chinese) doi: 10.3969/j.issn.1004-132X.2019.10.010 [10] 张利敏, 王根全, 王延荣, 等. 某型柴油机活塞销轴承磨损分析及表面型线设计[J]. 兵工学报, 2018, 39(10): 1892-1900 doi: 10.3969/j.issn.1000-1093.2018.10.003ZHANG L M, WANG G Q, WANG Y R, et al. Profile design and seizure analysis of piston pin bearing of a diesel engine[J]. Acta Armamentarii, 2018, 39(10): 1892-1900 (in Chinese) doi: 10.3969/j.issn.1000-1093.2018.10.003 [11] DE SOUZA RODRIGUES A, VILLALVA S G, GALLI L A F. Increasing of crankshaft structural strength by means of using non-straight bearings so called U-shape bearing[C]//SAE Brasil Congress & Exhibit, 2009: 36 [12] 张敬晨. U型连杆大头轴承润滑性能研究[D]. 济南: 山东大学, 2016ZHANG J C. Research of lubricating property of the U-shape connecting rod big bearing[D]. Ji'nan: Shandong University, 2016 (in Chinese) [13] KEPLER J A. On application of catenary principles to sandwich structure design–Sandwich/ catenary hybrid beams under uniformly distributed load[J]. Journal of Sandwich Structures & Materials, 2020, 22(2): 127-155 [14] PATIR N, CHENG H S. An average flow model for determining effects of three-dimensional roughness on partial hydrodynamic lubrication[J]. Journal of Lubrication Technology, 1978, 100(1): 12-17 doi: 10.1115/1.3453103 [15] PATIR N, CHENG H S. Application of average flow model to lubrication between rough sliding surfaces[J]. Journal of Lubrication Technology, 1979, 101(2): 220-229 doi: 10.1115/1.3453329 [16] ZHU D, CHENG H S, ARAI T, et al. A numerical analysis for piston skirts in mixed lubrication–part I: basic modeling[J]. Journal of Tribology, 1992, 114(3): 553-562 doi: 10.1115/1.2920917 [17] 袁兆成. 内燃机设计[M]. 2版. 北京: 机械工业出版社, 2012YUAN Z C. Internal combustion engine design[M]. 2nd ed. Beijing: China Machine Press, 2012 (in Chinese) [18] 孙志诚, 周博雅, 戴天禄, 等. 电动汽车续航里程估计准确度评价[J]. 科学技术与工程, 2019, 19(32): 344-350 doi: 10.3969/j.issn.1671-1815.2019.32.052SUN Z C, ZHOU B Y, DAI T L, et al. Evaluation method for estimation accuracy of bettery etectric vehicle cruising range[J]. Science Technology and Engineering, 2019, 19(32): 344-350 (in Chinese) doi: 10.3969/j.issn.1671-1815.2019.32.052