The thrust ball bearings are classified into two kinds: unidirectional
thrust bearing and bidirectional thrust bearing. The former can bear the
axial force in one direction and the latter can bear he axial forces in
two directions. Both unidirectional and bidirectional thrust ball
bearings cannot bear any radial force. Thrust ball bearing can limit axial displacement of shafts or housings in one or two direction, but not radial displacement. Therefore, the bearings are usally used with deep groove ball bearings.
Single direction thrust ball bearing consist of one row of balls ( with cage ), a shaft washer ( close fit with shaft ) and a housing ring ( loose fit with shaft and close fit with bore of bearing block ). They can not carry radial loads but axial loads in one direction, because the axial loads are well distributed on each bal, the loading capacity is higher, but the temperatue is high while working, and their limiting speed is lower.
Double direction angular contact thrust ball bearings are high precision bearings which are specilly designed for spindles of machine toole. They are able to carry axial loads in two directions, and they have more balls with small diameter. The centrifugal influence can be reduced as their 60° contact angle, so more suitable for high speed application.
It can carry axial loads that dimension series 2344 and 2349 double direction angular contact thrust ball bearings fit with dimension series NN30 and NU49 double row cylindrical roller bearings.
Double direction angular contact thrust ball bearings with class SP whose running accuracy is P4 and dimension accuracy is P5 can produced by us.