Main shaft of high speed report is the core component of high speed machine tool, the precision of each spare parts is unit of electric main shaft normally µm class, if beat,be 1 ～ 3µm commonly, main shaft stiffness is 100-300N/µm commonly, accordingly, electric main shaft the deflection of precision sum of errors of oneself of each spare parts is very small. However, when high speed runs, bearing hair quantity of heat is very big, cause bearing temperature rise very tall, cause heat to be out of shape. Heat is out of shape the error that cause is ambitious at deflection of precision sum of errors. And, heat is out of shape changed bearing directly tighten a condition beforehand, the treatment precision of the stiffness character that affects bearing and electric main shaft, serious when, the heat that brings about bearing even is occlusive, make electric main shaft is destroyed. The calorific problem of electric main shaft reduced his to apply medium dependability in actual production. The hot condition character that reason undertakes heating up an analysis to bearing and masters bearing is right the stability in raising electric main shaft to machine and dependability are all in all. Ball bearing of contact of horn of high speed nicety is a kind of bearing with the widest application in unit of machine tool main shaft, the article is research target with this kind of bearing, system of bearing of accurate to high speed main shaft made more significant hot characteristic analysis and calculation. What the attrition moment of force of bearing of nicety of 1 high speed and attrition heat up bearing is calorific and main concern with attrition moment of force, moment of force is larger, generated attrition heat is more also. According to the formula of Palmgren derivation, does the attrition moment of force of bearing basically have two parts: ? Beautiful jade of gourd ladle bear ＜ of Chu of bright of Σ of where of of of appearance of Yong of spoon of Gao of head of an ancient nationality in China of Ren Xun of Yu of peptone of Tuo of Gao of bright of which Σ of round attacks in type of? M0=10-7f0(vn)2/3dm3 (1) M1=f1P1dm (2) of Man of willful dumpling: FThe 0 coefficient;v that to be mixed with bearing type lubricant means concerns issue the athletic viscosity of lubricant for working temperature, mm²/r;n gives priority to axial rotate speed, r/min;dm is bearing pitch circle, the coefficient;P1 that Mm;f1 concerns to get bear with bearing type and place is the computational bear of moment of force of affirmatory bearing attrition, n;M0, m1 is attrition moment of force, n · Mm. Bearing contacts area heat to generate the spin campaign that still follows scroll body and bearing ferrule to concern, according to bearing ferrule channel below high speed academic, scroll body and spin of liner circle existence move, spin attrition moment of force is type of Msi= 3µsiQiaiei 8(3) in: &The law that Micro; is scroll body and raceway groove for the;Q of coefficient of friction of scroll body and raceway groove to osculatory load, n;a contacts elliptical long axle shaft for hertz, m;e is the 2nd kind of elliptical integral. Accordingly, the attrition heat of bearing can receive form of Hlot= 2p N(M0+M1)+Msiwsi 60(4) by following computation in: N gives priority to axial rotate speed, r/min. Wsi is angular velocity of motion of spin of scroll body inner ring, rad/s. By type (1) ～ type (4) is knowable, ask attrition is hotly to need the spin angular velocity of computational scroll body, formula of computation of this angular velocity is as follows: In type of Wsi=-wbsin(tgb-ai)+(w-wc)sinai (5) Wb=w[(Cosae+tgbsinae + Cosai+tgbsinai)gcosb]-1 1+gcosee 1-gcosei(6) Wc= W(1-gcosei) 1+cos(ai-ae)(7) : W gives priority to axial angular velocity, rad/s; Ai, ae contacts horn for the outer lane inside bearing, rad; Wb is rotation angular velocity, rad/s; Wc is angular velocity of scroll body revolution, in Rad/s G=Db/dm type: Db is scroll body diameter, mm. Tgb= Sinae Cosae+g(8)2 " main shaft one ferrule one grounder one bearing " hot analysis of the system pursues distributinging graph of node of temperature of 1 bearing system mixes bearing, main shaft bearing consider as a system, the attrition heat of this system is generated and heat is delivered is complex three-dimensional hot issue, calculate to simplify, assume the hot character of systematic Zhou Xiang is consistent, OK the heat that a plane makes a system to study a target analyses axial intercept. According to the point of view that Burton and Steph offer, attrition heat rolls 1:1 is made between body and ferrule in bearingdistributing, chafe namely heat has a half to enter scroll system, other in part enters ferrule. Use node network law to seek solution the temperature that each key orders this system, the temperature that gets whole system distributings state. Here, altogether established 9 temperature node, satisfied requirement of general calculative precision. Of each crucial temperature node if the graph is shown 1 times,distributing. Bearing is lubricant means lubricates for oil gas means, force convection coefficient to decide harder, according to experience formula computation forces convection coefficient here. H=0.
· of 332Kl · Pr1/3 (U)0.
In 5 Ux(9) type: Kl is the coefficient of thermal conductivity of lube, ) of W/(m2 ℃ ; Pr counts ice to be convective speed for Pulangte, m/s; V is the athletic viscosity of lube, mm2/s; X is diagnostic length, m. To scroll body, spend the exterior rate that takes bearing cage to velocity of flow, what diagnostic length takes bearing is medium diameter; To ferrule of inside and outside, 1/3 what spend each to take cage surface rate to velocity of flow, diagnostic length takes respective raceway groove diameter. When the system is in hot balance, the temperature of each node produces change no longer. Right now, the only thermal current of each node is 0. According to this, can get equation of 9 thermal current, form an equation group that includes 9 node temperature. This equation group is nonlinear equation group, use Newton, law of the abdicate that help cost begs all computers to be able to be solved. The heat conduction equation of radial of bearing ferrule, main shaft gives out below. In type of Q= 2pKC Te-Ti Ln(de/di)(10) : K is coefficient of thermal conductivity, w/(mK) ; C is bearing width, m; De, Di is the external diameter of each ferrule, internal diameter, m. Main shaft diameter is Q=KpW(T0-T ∞ to heat conduction equation) (in 11) type: W is the main shaft width of make choice of, m. The element of temperature rise of 3 influences bearing analyses the bearing model of this example to be 7013C, bearing and computational model parameter are: D=65mm D=100mm, d0=160mm, b=18mm, ls=30mm, lh=20mm. Foregone bearing tightens means to be beforehand constant pressure tighten beforehand, tighten force to be 300N beforehand. Main shaft rotate speed namely rotate speed of bearing inner ring is 20, 000r/min. Calculate: Below high speed, horn of contact of the outer lane inside bearing is respectively 24.
3 ° and 7.
2 ° , inside and outside encircles a law to suffer force to be each 729.
26N and 2391.
5N. Bearing is lubricant means lubricates for oil gas, speed of bearing cage surface is 18.
9m/s. Computation is in as a result watch 1 in give out. Express temperature of T1 T3 T4 T5 T6 T7 T8 of node of 1 node temperature 50.
2 56.
1 57.
2 49.
3 37.
1 34.
9 31.
The affects bearing rotate speed of 3 rotate speed is remarkable to influence of bearing temperature rise, bearing rotate speed is higher, attrition is calorific more serious, the temperature rise that many attrition thermal conductivity causes bearing is more apparent also. Graph 2 it is the temperature rise case that bearing leaves in different rotate speed. Can see, rotate speed is higher, temperature rise is faster also. Graph 2 rotate speed pursue to the influence of bearing node temperature the cutting power that the influence of 3 lubricant means to bearing temperature produces in the process of workpiece of cutting of influence cutting tool of cutting force makes bearing bears additional add load, these load are influential also to the attrition heat of bearing, affected the temperature rise of bearing secondhand. Cutting force basically affects bearing by outside the attrition moment that load action produces, but computation makes clear, this influence value is very little, accordingly, cutting around, the temperature rise change of bearing is not apparent. The influence grease of lubricant means is lubricant suit the situation with inferior rotate speed, its Dn cost is highest and average do not exceed 600 thousand, under photograph comparing, oil gas is lubricant can get used to higher rotate speed, its Dn value is highest can amount to 2 million, it is a kind of reliable high speed lubricant means. Graph 3 report oil gas lubricates and lubricant means checks oil the influence circumstance of bearing temperature, from this the graph can see, when grease lubricates to lift in rotate speed, bearing temperature is climbed litre very fast, explain unsuited high speed is lubricant; When oil gas is lubricant, those who follow rotate speed rise, bearing temperature is elevatory gentlier, lubricant and cooling effect is very good. 4 conclusion analyse computation through above, if make conclusions,can reach: Rotate speed is higher, the attrition moment of force of bearing is larger, generated attrition heat is more also, the temperature rise of bearing is faster also; Inside regular job limits, the effect that cutting force causes to bearing temperature rise is very little, consider more elements to chafe to bearing the influence of pitching moment, can make calculate result more accord with actual. To high speed bearing (Dn value is inside the limits of 2 million) , it is lubricant and OK to use oil gas very good inhibition the temperature rise of bearing.
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