Lubrication for worm reducer
A lubricant is used to reduce the friction of bearings and sliding surfaces in worm reducer and thus diminish the wear,heat,and possibility of seizure of the worm gear reducer.Although a layer of oil will eliminate the excessive friction of metal-to-metal contact,the friction within the oil film must be taken into worm reducer.The study of lubrication and the design of bearings is,therefore,concerned mainly with phenomena related to the oil film between the worm gear reducer.The literature on lubrication is very extensive,and a mathematical treatment of the subject is beyond the scope of this content.Fortunately,it is possible to make design calculations from the graphs obtained by mathematical analysis.
Load-carrying journal bearing, and worm reducer.
The flat plate in that is incapable of supporting a vertical load because no pressure exists in the oil film.If a vertical load were placed on the plate,the oil would squeeze out around the edges,and the plate would approach the surface beneath,resulting in metal-to-metal contact.If,however,the plates of worm gear reducer are tipped at a small angle to each other, the oil will be drawn into the wedgeshaped opening,and sufficient pressure will be generated in the film to support the load W.This fact is utilized in the thrust bearings for hydraulic turbines and propeller shafts of ships,as well as in the conventional journal bearing with flooded-oil lubrication for worm gear reducer.
Since the same quantity of oil is drawn past each cross section of worm gear ,the velocity distribution throughout the height of the film is no longer linear as it is for parallel plates.The velocity curve will be concave at the wider cross sections of worm reducer and convex at the narrower.
If the shaft of worm reducer in that carried a downward load,the journal would no longer remain central with the bearing.For the classical case of the infinitely long bearing,the shift of the journal cencenter is usually expressed as a proportion of the radial clearance,c.Thus,the shaft has shifted inches,where the eccentricity ratio is pure number less than unity.A copious of worm gear reducer supply of oil is assumed,which fills the entire clearance space,and thereby builds up sufficient pressure to support the load W.The bearing automatically adjusts itself to the imposed load.Thus,should W be increased,the shift to the left would become greater,and the resulting decrease of the film thickness would cause higher oil pressures,which would take care of the larger load.