Research On The Trace Grease Lubrication Technology In High Speed Spindle

High-speed spindle get rid of the traditional drive structure of the intermediate transmission links, directly driven by the built- in motor, to meet the requirements of high speed cutting machine tool for “the high speed, high precision, high reliability and small vibration”, widely used in the high speed machining technology. Grease lubrication bearings have the advantages of simple structure, convenient maintenance, low cost, sealing; between high speed bearing rolling elements and rings only a very small amount of grease can form enough oil film, maintaining lower hydrodynamic friction loss and very low operating temperature, generally used in high-speed spindle lubrication system.The more grease fill in bearing, the higher severer churning generate bearing temperature, shorer the service life of bearing; filling grease amount is too small, between bearing rollers and the rings are not formed enough oil film, bringing about friction and wear serious, vibration intensified, reducing precision spindle, shortening the service life of the main shaft. Therefore, the study of trace greased lubrication technology of the high-speed spindle is of great significance to improve the performance of high-speed spindle.First in view of the question of trace grease lubrication high speed bearing, for example, high temperature blackening due to wear and tear, grease leakage, analysis causes of failure, consider the reason is that poor thixotropic properties and abrasion resistant performance result in elevated temperature, lubricating grease loss, friction and wear serious. So carry out studying on the properties of high speed grease. In accordance with the grease selection principle, select high speed grease(KLUBER ISOFLEX NBU15/FAG SPEED2,6(L75)/l252/ LGLT2), according to the national standard, using standard instruments, thixotropic performance, anti-wear performance, anti- friction performance and extreme pressure test will be experiented. Results show that L252 below 80℃ thixotropic performance, anti-wear performance and anti- friction performance are best, extreme pressure performance medium, comprehensive performance is higher than of similar products. The anti-wear test of high-speed grease KLUBER mixed 2%~6% of anti-wear and extreme pressure additives were completed, the result shows that the additive content of 6%, grease anti-wear performance and anti-friction properties improved the most.Then, for trace grease lubrication of the high speed bearing,phenomena, rings of severe plastic deformation and rings surface of grievous wear, are analyzed. O n the one hand, grease the film thickness insufficient to separate two metal contact surface, cause friction contact, and aggravate friction and wear; on the other hand, the contact stress of the hydrodynamic lubrication contact zone is too large, beyond oil film or bearing materials capacity, leading to the rings severe plastic deformation. Therefore, carry out high speed grease in the condition of high speed analysis and contact area of stress analysis. Application isothermal elastic hydrodynamic lubrication theory, forecast to lubrication states under various working conditions, results show that: four high-speed grease lubricating film ha ve enough carrying capacity, while at high speed(above 30000 r / min) the maximum stress of lubricating oil film close to or even surpass the ring material yield stress cause the ferrule deformation; L252 under given conditions are in full film lubrication and have best lubrication condition.Finally, aim at a small amount of grease lubrication for high speed bearing, existing high temperature and vibration problem, implement filling grease amount test, analysis of grease filling amount impact on bearing temperature, torque and vibration. The vibration and temperature test of the bearing, FAG HCS7003-C-T-P4S-UL, were carried out by the independent design test rig, torque test in BRG-3000 moment device. Considering different amount grease, bearing performance test results show that the run-in procedure benefit grease redistribution, grease crowded out from ring can be used as "feed groove", replenishment the consumption of lubricating greases in the operation process; filled grease amount in 0.25 g, bearing has better comprehensive performance. Compared four kinds of high-speed grease, L252 possess the best comprehensive performance than remaining grease.