Study On Liquid Film Seal For Variable Frequency Motor Bearing Under Special Working Conditions

Skeleton oil seal,V ring seal and packing seal are often used by the general motor seal.Forced lubrication bearing variable frequency motor is at special condition which includes frequent start-stop,high speed,positive and negative rotation.Lubricating medium leakage appeared in original seal,which weakened electrical insulation properties and led to short circuit.Considering good application of the early mechanical seal on the bearing seal,advantage of liquid membrane seal products at present stage and drawbacks of original packing,a new type of film sealing has been developed.The variable frequency motor bearing sealing reliability problems will be solved and valuable experience will be accumulated.Based on the sealing film comprehensive research status and development of bi-directional rotation groove,the following four aspect mainly has been introduced.Firstly,the small axial film sealing for variable frequency motor in the above-mentioned conditions has been designed;Secondly,the mixed friction model has been used to compare the seal performance of bidirectional rotating groove type.when liquid film can not fully support the closing force,end face seal face morphology?roughness and waviness,taper,the tropism?effect on the sealing performance has been analysised;Thirdly,when liquid film can bear completely closing force,introduced Schnerr-Sauer cavitation model to meet mass conservation,the effect of operating parameters and groove parameters have been studyed;Finally,the new type of liquid membrane seal has been researched.It is not the whole liquid film lubrication non-contact mechanical seal in the traditional sense.But it stays mixed friction lubrication state at low speed,which is a non-contact mechanical seal.It can improve the bearing capacity and strengthen face lubrication.It stays full liquid film lubrication state at high speed,which is a non-contact mechanical seal with upstream pumping effect.The following conclusions have been drawed through the above work.New seal device has been designed.The optimal end surface topography parameters has been determined.End surface morphology characterization is?<1.The degree of wave number is 7⁹.Wave amplitude is 0.2?m⁰.4?m.Standard deviation of roughness is 0.05?m⁰.2?m.Taper surface is 0⁰.1x10^-3rad.The influence fact laws have been summarized.The best optimization parameters of mushroom shaped groove structure has been determined.These conclusions provides a reference for the optimization design of mushroom shaped groove.