高转速行星齿轮止推垫圈流体动压润滑特性

以直齿行星排的行星轮止推垫圈为对象,为了减小其与行星齿轮之间因轴向力而导致的磨损,通过对止推垫圈加工径向沟槽的方法,对其进行流体动压润滑设计,使止推垫圈与行星轮间有相对运动时产生流体动压承载力,从而使两者之间实现非接触而减小磨损.因结构的对称性,允许正反向旋转且加工容易而选择径向直线矩形槽.建立了定常雷诺方程的模型,应用有限体积法对其进行离散求解.分析了槽数、槽宽比、槽深和径向宽度等结构参数对垫圈流体动压力承载性能、润滑油流量和温升的影响规律.考虑到工程应用,着重对较少油槽数量（2～12）情况下的润滑特性进行了分析.结果表明：槽数约为20时,油膜具备最大的承载力;油槽数量介于10～60时具备较大的承载力;槽区角度与周期槽角度之比约为0.5时具有最佳承载力,径向宽度越大则承载力越大;槽数越多、槽深越大、径向宽度越大,流量越大,反之减小;槽宽比增大能使流量减小;降低润滑油温升的措施为增加垫圈槽数、增大径向宽度,使槽深处于10～40μm.

Hydrodynamic lubrication characteristics of planet gear thrust washer used in high-speed planetary transmission

For the washer in planetary transmission with spur gears,in order to reduce wear between the thrust washer and planet gear due to the force in the axis direction,hydrodynamic lubrication design was presented by machining rectangular grooves in the radial direction into one side of thrust washer.Such grooves can result in a hydrodynamic pressure to separate the contact surfaces and reduce the wear accordingly when there is a relative movement between the planet gear and thrust washer.Rectangular grooves were chosen due to their symmetrical structure,two rotational directions and easily to be machined.A steady Reynolds equation was set up and the finite volume method（FVM）was used to obtain its numerical solutions.The effects of number of grooves,ratio of groove angle to periodic groove angle,depth of grooves and radial width etc on carrying capacity of hydrodynamic washer,oil flow rate and temperature rise were studied.Considering feasibility of application,the lubrication characteristic was analyzed for the cases with less number of grooves（2-12）.The results show that when the number of grooves is about 20,the carrying capacity of oil film is the highest.When the number of grooves is in the range of 10 to 60,if the ratio of groove angle to periodic groove angle is about 0.5,the carrying capacity will be better.Moreover,the wider the radial width of washer,the higher the carrying capacity.More number of grooves,deeper groove depth and wider groove radial width increase the oil flow rate or vice versa.Larger ratio of groove angle to periodic groove angle results in a low oil flow rate.The measures of decreasing temperature rise are more number of grooves,wider radial width to make sure the groove depth is 10-40 μm.