困油压力对滑动轴承润滑状态的影响
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摘要
为研究困油压力对轴承润滑状态的影响,在一个困油周期内,基于纯流体润滑状态设计要求,提出轴承-轴颈间所必需的承载量系数计算公式;依据泵样机参数,提出轴承-轴颈间所能提供的承载量系数的多项式拟合式;由所必需的承载量系数公式等于所能提供的承载量系数的定值优化方法,建立出困油压力与最小油膜厚度间的对应关系。通过一案例,对是否考虑困油压力的润滑状态计算结果进行比较和分析。案例分析结果表明:困油压力导致径向力增加45%～59%;导致最小油膜厚度降低19.6%～24.3%;困油压力造成轴承-轴颈间处于混合润滑状态,达不到原始的纯流体润滑状态设计要求。因此,困油压力对润滑状态影响较大,在泵轴设计中应充分考虑困油压力的影响,从而在结构上尽量缓解困油压力。
In order to study the effect of trapped-oil pressure on lubrication state of journal bearing in external gear pumps,a formula for calculating the needed load-carrying factors between bearing and journal based on the design requirements of all fluid lubrication state was established.A polynomial formula of provided load-carrying factors by a prototype of a gear pump was fitted based the parameters of the prototype by Excel software.Through the zero value solution of the needed load-carrying factors minus the provided load-carrying factors tby the programming solver of Excel software,the corresponding relationship between the trapped-oil pressure and the minimum oil film thickness on journal bearing was derived.The lubrication state of the journal bearing of a prototype of a gear pump was studied when considering and not considering the trapped-oil pressure.The results of the prototype show that the trapped-oil pressure causes the increasing of the radial force from 45% to 59%,and the decreasing of the minimum oil film thickness from 19.6% to 24.3%.The journal bearing is in mixed lubrication state because of the effect of trapped-oil pressure,which can not meet the original design requirements of all fluid lubrication state.It is concluded that the oil trapping pressure has a great influence on the lubrication condition,the influence of oil trapping pressure should be fully considered in the design of pump shaft,so as to alleviate the oil trapping pressure as far as possible in structure.
In order to study the effect of trapped-oil pressure on lubrication state of journal bearing in external gear pumps,a formula for calculating the needed load-carrying factors between bearing and journal based on the design requirements of all fluid lubrication state was established.A polynomial formula of provided load-carrying factors by a prototype of a gear pump was fitted based the parameters of the prototype by Excel software.Through the zero value solution of the needed load-carrying factors minus the provided load-carrying factors tby the programming solver of Excel software,the corresponding relationship between the trapped-oil pressure and the minimum oil film thickness on journal bearing was derived.The lubrication state of the journal bearing of a prototype of a gear pump was studied when considering and not considering the trapped-oil pressure.The results of the prototype show that the trapped-oil pressure causes the increasing of the radial force from 45% to 59%,and the decreasing of the minimum oil film thickness from 19.6% to 24.3%.The journal bearing is in mixed lubrication state because of the effect of trapped-oil pressure,which can not meet the original design requirements of all fluid lubrication state.It is concluded that the oil trapping pressure has a great influence on the lubrication condition,the influence of oil trapping pressure should be fully considered in the design of pump shaft,so as to alleviate the oil trapping pressure as far as possible in structure.
引文
[1]李玉龙.外啮合齿轮泵困油机理、模型及试验研究[D].合肥:合肥工业大学,2009.
[2]MUCCHI E,DALPIAZ G,FERNNDEZ DEL RINCN A.Elastodynamic analysis of a gear pump.Part I Pressure distribution and gear eccentricity[J].Mechanical Systems and Signal Processing,2010,24(7):2160-2179.
[3]MUCCHI E,DALPIAZ G,RIVOLA A.Elastodynamic analysis of a gear pump.Part II Meshing phenomena and simulation results[J].Mechanical Systems and Signal Processing,2010,24(7):2180-2197.
[4]MUCCHI E,DALPIAZ G.Elasto-dynamic analysis of a gear pump.Part IV Improvement in the pressure distribution modelling[J].Mechanical Systems and Signal Processing,2015,s50/51:193-213.
[5]CASOLI P,VACCA A,FRANZONI G,et al.Effects of some relevant design parameters on external gear pumps operating:numerical predictions and experimental investigations[C]//Proceedings of 6IFK Internationales Fluidtechnisches Kolloquium,Dreden:IFK,2008.
[6]FIEBIG W,KORZYB M.Vibration and dynamic loads in external gear pumps[J].Archives of Civil and Mechanical Engineering,2015,15(3):680-688.
[7]李玉龙.一种具有耳形卸荷槽的外啮合齿轮泵ZL201310482913.7[P].2013-10-04.
[8]李玉龙.齿轮泵圆形卸荷槽下的困油压力分析[J].中国农业大学学报,2014,19(4):155-160.LI Y L.Trapped-oil pressure analysis of gear pump with arc unloading groove[J].Journal of China Agricultural University,2014,19(4):155-160.
[9]刘巍,王安麟,单学文,等.外啮合高压齿轮泵圆柱滚子轴承应用分析研究[J].机械设计,2014,31(9):20-25.LIU W,WANG A L,SHAN X W,et al.Application analysis and research of cylindrical roller bearing in external gear high pressure pump[J].Journal of Machine Design,2014,31(9):20-25.
[10]何存兴.液压元件[M].北京:机械工业出版社,1982.
[11]《机械设计手册》编委会.机械设计手册单行本:滑动轴承[M].北京:机械工业出版社,2007.
[12]李玉龙.齿轮泵最大困油压力解析式的建立与验证[J].农业工程学报,2013,29(11):71-77.LI Y L.Establishment and verification of analytic formula for maximum trapped-oil pressure in external gear pump[J].Transactions of the Chinese Society of Agricultural Engineering,2013,29(11):71-77.
[13]李玉龙.齿轮泵困油膨胀区的最小压力研究[J].排灌机械工程学报,2013,31(12):1049-1055.LI Y L.The minimal trapped-oil pressure of expansion stage in external gear pump[J].Journal of Drainage and Irrigation Machinery Engineering,2013,31(12):1049-1055.
[2]MUCCHI E,DALPIAZ G,FERNNDEZ DEL RINCN A.Elastodynamic analysis of a gear pump.Part I Pressure distribution and gear eccentricity[J].Mechanical Systems and Signal Processing,2010,24(7):2160-2179.
[3]MUCCHI E,DALPIAZ G,RIVOLA A.Elastodynamic analysis of a gear pump.Part II Meshing phenomena and simulation results[J].Mechanical Systems and Signal Processing,2010,24(7):2180-2197.
[4]MUCCHI E,DALPIAZ G.Elasto-dynamic analysis of a gear pump.Part IV Improvement in the pressure distribution modelling[J].Mechanical Systems and Signal Processing,2015,s50/51:193-213.
[5]CASOLI P,VACCA A,FRANZONI G,et al.Effects of some relevant design parameters on external gear pumps operating:numerical predictions and experimental investigations[C]//Proceedings of 6IFK Internationales Fluidtechnisches Kolloquium,Dreden:IFK,2008.
[6]FIEBIG W,KORZYB M.Vibration and dynamic loads in external gear pumps[J].Archives of Civil and Mechanical Engineering,2015,15(3):680-688.
[7]李玉龙.一种具有耳形卸荷槽的外啮合齿轮泵ZL201310482913.7[P].2013-10-04.
[8]李玉龙.齿轮泵圆形卸荷槽下的困油压力分析[J].中国农业大学学报,2014,19(4):155-160.LI Y L.Trapped-oil pressure analysis of gear pump with arc unloading groove[J].Journal of China Agricultural University,2014,19(4):155-160.
[9]刘巍,王安麟,单学文,等.外啮合高压齿轮泵圆柱滚子轴承应用分析研究[J].机械设计,2014,31(9):20-25.LIU W,WANG A L,SHAN X W,et al.Application analysis and research of cylindrical roller bearing in external gear high pressure pump[J].Journal of Machine Design,2014,31(9):20-25.
[10]何存兴.液压元件[M].北京:机械工业出版社,1982.
[11]《机械设计手册》编委会.机械设计手册单行本:滑动轴承[M].北京:机械工业出版社,2007.
[12]李玉龙.齿轮泵最大困油压力解析式的建立与验证[J].农业工程学报,2013,29(11):71-77.LI Y L.Establishment and verification of analytic formula for maximum trapped-oil pressure in external gear pump[J].Transactions of the Chinese Society of Agricultural Engineering,2013,29(11):71-77.
[13]李玉龙.齿轮泵困油膨胀区的最小压力研究[J].排灌机械工程学报,2013,31(12):1049-1055.LI Y L.The minimal trapped-oil pressure of expansion stage in external gear pump[J].Journal of Drainage and Irrigation Machinery Engineering,2013,31(12):1049-1055.