Depending on the bearing housing design, a distinction is made between two main categories of ball bearing units, specifically plummer block housings and flange bearings.
Flange bearings are made up of the insert and a relatively flat ball bearing housing.
Equipped with 2 or 4 bore holes for attachment, they are known as 2-hole flange or 4-hole flange bearings.
Flange bearings are usually screwed in the direction of the shaft axis to a mounting surface (flanged in position).
The most common designation for the flange bearing housing is "F". The subsequent 3-digit code designates the suitable ball bearing inserts.
One example is the designation F 206. Here, the letter F stands for flange bearing. The number 2 stands for the middle ball bearing series (here 62-series) and the following numbers 06 stand for the matching bearing insert with the bore code 06. This means that the housing can be combined with all bearing inserts with bore code 06 (UC 206, HC 206, SA 206, SB 206, CS 206).