Bearings manufactured pre-set for preload

Universally matchable bearings and matched bearing sets are manufactured pre-set in different preload classes to meet varying requirements regarding rotational speed, rigidity, and operating temperature.

The amount of preload depends on the bearing series, the contact angle, the internal geometry, and the size of the bearing and applies to bearing sets in back-to-back or face-to- face arrangements. Preload values are not standardized and are listed in the product table.

Bearings in the S70 .. W series are manufactured as single universally matchable bearings or as matched sets of two bearings. In either case, arranged back-to-back or face-to-face, standard preload prior to mounting is zero.

Matched bearing sets with a special preload can be supplied on request. These bearing sets are identified by the designation suffix G followed by a number. The number is the mean preload value of the set expressed in daN. Special preload is not applicable for sets of universally matchable bearings consisting of three or more bearings. Matched bearing sets consisting of three or more bearings have a heavier preload than sets with two bearings. The preload for these bearing sets is obtained by multiplying the values for a single bearing by a factor listed in table 1.

719 .. D, 70 .. D and 72 .. D series

Bearings in the 719 .. D, 70 .. D and 72 .. D series are manufactured to four different preload classes:
  • class A, extra light preload
  • class B, light preload
  • class C, moderate preload
  • class D, heavy preload

718 .. D, 719 .. E and 70 .. E series

Bearings in the 718 .. D, 719 .. E and 70 .. E series are manufactured to three different preload classes:
  • class A, light preload
  • class B, moderate preload
  • class C, heavy preload

These preload classes are valid for:

  • single, universally matchable bearings
  • sets of universally matchable bearings
  • matched bearing sets

In applications where high speeds take precedence over the degree of rigidity, the following additional preload classes are available:

  • class L, reduced light preload for asymmetrical bearing sets
  • class M, reduced moderate preload for asymmetrical bearing sets
  • class F, reduced heavy preload for asymmetrical bearing sets

As indicated, these preload classes are only available for matched bearing sets that are asymmetrical, e.g. TBT, TFT, QBT, and QFT. Bearing sets in the L, M or F preload class consisting of three or four bearings, have the same preload as sets with two bearings in the A, B or C preload class. Therefore, the preload for matched bearing sets that are asymmetrical, e.g. TBT, TFT, QBT, and QFT, can be obtained directly from the product tables.

An example of the preload possibilities for an arrangement with a matched set of 7014 CE bearings is presented in table 2.

719 .. B and 70 .. B series

Bearings in the 719 .. B and 70 .. B series are manufactured to three different preload classes:
  • class A, light preload
  • class B, moderate preload
  • class C, heavy preload
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