Double row self-aligning ball bearings
Double row self-aligning ball bearings have spheral raceway on the outer ring. They can misalign and also the misalignment of seating is acceptable for them. Double row self-aligning ball bearings are produced with cylindrical or tapered bore and they are non-separable.
Misaligning ability without impairing the bearing‘s proper functions allows the application of the bearings where a higher bore misalignment in bearing housings or deflection and oscillation of shaft can be expected. Because of the small contact angle and imperfect adhesion of the balls to the raceways they are not suitable for higher axial loads.
Main dimensions of double row self-aligning ball bearings specified in the dimension tables are in accordance with the international standards ISO 15. The adapter sleeve dimensions also comply with international standards ISO 113.
Bearings with tapered bore have taper 1:12. Adapter sleeves are used to mount bearings with tapered bore on cylindrical shafts. Sleeve designation of the individual bearings are stated in the table section.
Double row self-aligning ball bearings have in the basic application pressed steel cage that is not indicated. There can be one-piece cages (line 12…, 13…) and two-part cages (line 22…, 23…).
The double row self-aligning ball bearings are commonly manufactured within the normal tolerance class P0. For special applications requiring high accuracy or with high rotation speed bearings with higher tolerance classes P6, P5, P4 are used. Limiting values of dimension deviations and operation are stated in the norm ISO 492.
The commonly manufactured double row self-aligning ball bearings have normal radial clearance stated by the manufacturer. For special applications bearings with reduced radial clearance (C2) or with increased radial clearance (C3, C4, C5) can be supplied.
The commonly manufactured double row self-aligning ball bearings have a normal vibration level specified by the manufacturer. For special arrangements demanding for silent operation bearings with reduced vibration level (C6) are supplied.
Combination of symbols
The symbols for the tolerance classes, internal bearing clearances and vibration levels are combined with the simultaneous omission of the symbol C in the second and the following bearing special characteristics e.g.:
P6 + C3 = P63
C3 + C6 = C36
Stabilisation for operation at higher temperature
For operating temperature higher than 120°C specially stabilized double row self-aligning ball bearings with stabilized dimensions for operating temperature from 150°C to 400°C (S0, S1, S2, S3, S4,S5) are produced. Delivery of stabilized bearings should be discussed in advance.
Double row self-aligning ball bearings can accept misalignment of the bearing rings.
Values of permissible misalignment without affecting the correct bearing operation are stated in the following table.
|Bearing Type||Permissible Misalignment|
|126, 13, 23||3º|
Radial equivalent dynamic load
Pr = Fr + Y1.Fa – for Fa/Fr ≤ e (kN)
Pr = 0,65.Fr + Y2.Fa – for Fa/Fr > e (kN)
Factor values e, Y1 a Y2 for individual bearings are stated in the table section.
Radial equivalent static load
Por = Fr + Y0.Fa (kN)
Factor values Y0 are stated in the table section.
The designation of basic designs and common modifications of the bearings is specified in the dimension tables. Modification of the basic design is indicated by additional symbols according to the norm STN 02 4608.