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Design of associated components

Shaft requirements

To achieve a reliable seal and sufficiently long service life, the surface of the seal counterface should have a hardness of at least 55 HRC or 600 HV. The surface roughness of the counterface on the shaft of rotary applications should lie between Ra 0,2 and 0,8 µm, if the maximum permissible circumferential speeds are to be used. For linear applications the maximum permissible roughness of the counterface is Ra 0,3 µm.
The diameter of the shaft at the counterface should be machined to g7 up to k7 tolerance classes. The shaft end should have a 15 to 30° lead-in chamfer to prevent damage to the seal lips during mounting. Appropriate minimum dimensions for lead-in chamfers (fig 1) are:
  • h1 = 0,3 mm for seals with an outside diameter d2 ≤ 30 mm
  • h1 = 0,5 mm for seals with an outside diameter d2 > 30 mm.

Housing requirements

The housing bore tolerance classes normally recommended for needle roller bearings provide a sufficient interference fit for the seals.
In general, these seals can be fitted into housing bores machined to G7 up to R7 tolerance class.
No additional axial location of the seal is needed.
To simplify mounting, the housing bore should have a 15 to 30° lead-in chamfer. Appropriate minimum dimensions for lead-in chamfers (fig 2) are:
  • h = 0,3 mm for seals with an outside diameter d2 ≤ 30 mm
  • h = 0,01 d2 mm for seals with an outside diameter d2 > 30 mm.
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