1, surface roughness, due to the shaft speed and the amount of oil is different, the general shaft of the roughness is too large or too small, will affect the seal leakage and wear. The allowable range of the surface roughness of the shaft is Rz1.0 to 5.0 μm; Ra0.2 to 0.8 μm. Seal the rotary shaft with oil and take 2.5 to 1.6 μm Rz.
2, hardness, the surface hardness of the rotating shaft generally take ≥ 35HRC. When the medium is dirty, there are pollution impurities from the outside, or the shaft speed is >12m/s, the surface hardness of the shaft should be 55HRC or more, and the depth of the hardened layer on the shaft surface should be >0mm.
3, the shaft chamfer, the recommended value of 15 ° ~ 30 °, in order to allow the oil seal is indeed installed, without damaging the lip seal principle.
4. Shaft processing. Correct shaft machining is the decisive factor for ensuring the normal operation of the sealing system. The suitable oil sealing shaft processing method is horizontal feed precision grinding, emery paper polishing. The unsuitable processing method is finishing on the lathe, superfinishing, rolling, emery polishing (sandpaper grinding in the axial movement).
5, the shaft material, mainly ordinary carbon structural steel, such as C35 and C45, in addition, to cast iron, ceramics, resin plastic, but the shaft of the latter three kinds of material seals have defects.