Research On The Operating Characteristics Of Journal Bearing For High Speed Planetary Gear Set

In recent years,with the popularity of planetary transmission,higher requirements are proposed for the use of planetary transmission on the high-power,heavy-duty conditions.Planetary gears play an important role in the power transmission of planetary transmission.However,because of the speed limit and poor impact resistance of the rolling bearing which supports the planetary gear,it limits the development of transmission mechanism for high power density and high speed.A scheme using journal bearings instead of rolling bearings was proposed.In order to study planetary gears,it is important to know the running state of the journal bearing in the planetary transmission.In this paper,the theoretical analysis,numerical solution and experimental study were carried out on the operation performance,load distribution performance and parameters,so as to guide the design of high speed planetary gear set.Firstly,the hydrodynamic mathematical model of planetary gear journal bearing was established,and the basic characteristics of journal bearing when operating were obtained.The appropriate structural parameters were obtained,namely,the ratio of width to diameter is 1,the relative gap is from 0.0015 to 0.002 and higher fluid inlet temperature is suitable for the high-speed operation of the planetary transmission.And the effect of the oil supply position on the running performance was studied.It is considered that the oil supply position of 60° improves the carrying capacity.On the basis of the hydrodynamic mathematical model of the planetary gear journal bearing,the surface roughness was taken into consideration for mixed support.The influence of different surface roughness,different operating conditions and structural parameters on the performance of the planetary transmission was analyzed in detail.The surface roughness of 1.6?m was chosen as the economic parameter.The planetary gear journal bearing test platform was designed and built and the accuracy of numerical calculation was verified.Then the concept of variable stiffness of the planetary gear support was proposed and through the equivalent calculation model the load distribution performance was calculated.The running path of the central gear was solved by the dynamic equation and the stability of the system was analyzed.Finally,the accuracy of theoretical calculation was verified by experiments.