Imported bearing surface integrity

Discussion in 'The Bike Cafe' started by sawfwetg, Nov 2, 2014.

  1. sawfwetg

    sawfwetg New Member

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    1. Imported Parameter Of SKF Bearings bearing surface roughness Slow feed grinding wheel and workpiece length of contact arc z. Big, faster than the big, single diamond grits on the grinding force is small, with f grinding time. Extended, grinding wheel wear is not serious, grinding wheel topography changes little, thus imported bearing parts surface roughness change is slow, figure 8 to 9 slow feed grinding surface roughness is given with faster than g. Early state depends on the grinding wheel dressing, speed ratio increases, roughness decreased. 2. Imported bearing surface of grinding burn Slow feed grinding of grinding temperature is not high, but because of the grinding depth n. Big, the grinding wheel and workpiece contact area is large, when grinding fluid injection, flushing pressure is low, and insufficient pressure and discharge grinding wheel choose not to at that time, also in the contact area on the varying degree burns. C. R.S haft burn research thought arises, the normal grinding force increase, reduce the tangential grinding force. This phenomenon is a result of grinding fluid caused by a transition from nuclear boiling to film boiling. Grinding fluid nucleation boiling at high temperatures, the bubble growth, quantity of heat to send out bubble surface, grinding fluid coefficient of heat transfer increases sharply. In the film boiling, the surface is completely covered with a thin layer of steam film, heat transfer to the grinding fluid can only through the membrane by way of conduction, convection and radiation, heat conduction ability has fallen sharply. Because of the slow feed grinding grinding can be big, heat flow increase. Increase of heat flow will be passed to the grinding fluid and the workpiece. In the early part of the heat flow to the grinding fluid is far more than from the workpiece. When than grinding can increase significantly, a sharp rise in the temperature of one point in the contact arc, it can make the contact area of the grinding fluid from nuclear boiling to film boiling, the point at which the quantity of heat flow to the grinding liquid decreased dramatically, to burn point temperature on temperature of components, lead to burn workpiece. In addition, the temperature rises rapidly, the formation of thermal expansion will increase significantly. Thermal expansion amount increases, when the grinding depth is greater than the effective, is to make the grinding force increases. Once more than a point on the workpiece temperature burn temperature, thermal expansion will have a significant influence on grinding force. In slow feed grinding, grinding and even than the incoming workpiece heat unchanged, under the condition of grinding fluid to reduce, exposed burns, imported bearing grinding temperature rise sharply, the normal grinding force increase.
     
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