主轴颈圆柱度对发动机轴承润滑特性的影响
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摘要
基于制造效率和成本的平衡考虑,发动机曲轴的轴颈圆柱度不可避免地产生公差,从而对轴承副润滑状态、摩擦功耗和服役性能产生重要影响。本研究针对某三缸发动机,基于弹性流体润滑(EHD)理论分析曲轴主轴颈圆柱度对主轴承润滑性能的影响。首先将主轴颈圆柱度分解为沿轴颈径向的圆度和轴向的腰鼓度及轴心直线度,通过Kriging方法建立形位尺寸与轴承摩擦功间代理模型;然后基于遗传算法进行优化求解,进而评估轴颈圆柱度尺寸在公差范围内对轴承润滑的影响规律。结果表明,轴颈圆柱度对于轴承润滑状态有重要影响,在公差范围内会使得轴承摩擦功明显增大,但是提供了轴承润滑状态小幅度改善的可能性。其中腰鼓度的影响最大,使得轴承摩擦功变化27.7%;直线度的影响次之,导致摩擦功变化18.9%;而轴颈圆度的影响十分微小,仅为3.1%。
Manufacturing tolerance of journal cylindricity is inevitable with the consideration of manufacturing efficiency and cost. Based on the elastohydrodynamic(EHD) theory,effects of cylindricity for main journals in a three-cylinder engine on bearing lubrication are analyzed. In this study,cylindricity of main journal is equivalent to degree of barrel and straightness of journal center along the axial direction and roundness along the radial direction.The kriging method is used to establish the agent model between the geometric dimensions and bearing friction loss. And based on genetic algorithm,the influence of geometric dimensions on bearing lubrication is obtained. The results show that the journal cylindricity has an important influence on the lubrication of engine bearing. Within the tolerance range, the friction loss of the bearing will increase significantly, but it may also lead to a slight improvement in the lubrication of bearing. And the maximum influence of straightness is 18. 9%,while the effect of roundness is very small,only 3.1%.
Manufacturing tolerance of journal cylindricity is inevitable with the consideration of manufacturing efficiency and cost. Based on the elastohydrodynamic(EHD) theory,effects of cylindricity for main journals in a three-cylinder engine on bearing lubrication are analyzed. In this study,cylindricity of main journal is equivalent to degree of barrel and straightness of journal center along the axial direction and roundness along the radial direction.The kriging method is used to establish the agent model between the geometric dimensions and bearing friction loss. And based on genetic algorithm,the influence of geometric dimensions on bearing lubrication is obtained. The results show that the journal cylindricity has an important influence on the lubrication of engine bearing. Within the tolerance range, the friction loss of the bearing will increase significantly, but it may also lead to a slight improvement in the lubrication of bearing. And the maximum influence of straightness is 18. 9%,while the effect of roundness is very small,only 3.1%.
引文
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[13]WANG B,ZHOU J,XU M.Effects of journal roundness phase and amplitude on lubrication of engine bearings with consideration of straightness[J].SAE International Journal of Passenger CarsMechanical Systems,2017,10(2):465-473.
[14]周龙,张玉银,许敏,等.基于多体动力学和遗传算法的发动机活塞型线优化设计[J].内燃机工程,2014,35(5):17-23.
[2]MEHENNY D S,TAYLOR C M,JONES G J,et al.The influence of circumferential waviness of the journal on the lubrication of dynamically loaded journal bearings[C]//SAE International Congress and Exposition,1997.
[3]曾海景,徐武彬,魏塬,等.圆度误差对滑动轴承-转子系统摩擦功率损耗的影响[J].中国机械工程,2012,23(8):906-909.
[4]向建华,邹林峰,廖日东.轴颈圆度误差对滑动轴承润滑性能的影响研究[J].北京理工大学学报,2012,32(12):1241-1246.
[5]XU H,MIAN O,PARKER D.The impact of axial bearing profile on engine bearing performance[R].SAE Technical Paper,2003.
[6]JUNIOR D D,GALLI L A F,CRUZ R F D.Lubrication investigation of a non-straight internal combustion hydrodynamic bearing[C]//SAE Brasil 2009 Congress and Exhibit,2009:1258-1266.
[7]周玮,廖日东,郭珍.直线度误差对活塞销轴承润滑性能的影响[J].车用发动机,2016(3):47-51.
[8]GULWADI S D,SHRIMPLING G.Journal bearing analysis in engines using simulation techniques[Z].SAE Technical Papers,2003.
[9]RESCH T,SCHWEIGER C,OFFNER G,et al.Numerical investigation in rotor motion and elasto-hydrodynamic rotor bearing behavior of a rotary engine using flexible multi-body dynamics[C]//SAE World Congress&Exhibition,2007:1515-1520.
[10]AVL LIST GMBH.Excite powerunit theory manual[M/CD].Austria,AVL List Gm BH,2014
[11]GREENWOOD J A,TRIPP J H.The contact of two nominally flat rough surfaces[J].ARCHIVE Proceedings of the Institution of Mechanical Engineers,1970,196(1):1847-1982.
[12]邱宇,许敏,李冕.基于多体动力学的发动机主轴承润滑特性Kriging建模[J].机械设计与研究,2012,28(3):44-50.
[13]WANG B,ZHOU J,XU M.Effects of journal roundness phase and amplitude on lubrication of engine bearings with consideration of straightness[J].SAE International Journal of Passenger CarsMechanical Systems,2017,10(2):465-473.
[14]周龙,张玉银,许敏,等.基于多体动力学和遗传算法的发动机活塞型线优化设计[J].内燃机工程,2014,35(5):17-23.