EN logo ZKL Group

Under bearing tolerance, dimension and operation accuracy is understood. Bearings are manufactured in tolerance classes P0, P6, P5A, P4, P4A, P2, SP and UP.

Tolerance class P0 is the basic one and a decreasing number in designation means the higher bearing tolerance class. Limiting values for dimension and operation acuracy shown in tables 20 to 30 comply with the standard ISO 492 and ISO 199 (STN 02 4612). Designation P5A and P4A are used for bearings manufactured in corresponding tolerance class (P5, P4), or selected parameters are in higher tolerance class than P5 and P4.

Tolerance Symbols and Their Meaning

d - nominal bore diameter

d₁ - nominal diameter of larger theoretical tapered bore diameter

d₂ - nominal diameter of shaft washer of double direction thrust bearings

∆d_s - deviation of single bore diameter from nominal

∆_dmp mean cylindrical bore diameter deviation in single radial plane
 (for tapered bore ∆_dmp is valid for theoretical bore diameter)

∆_d1mp - deviation of mean larger theoretical diameter of tapered bore

∆_d2mp - mean shaft washer bore diameter deviation of double direction 
 thrust bearings in single radial plane

V_dp - single bore diameter variation in single radial plane

V_dmp - mean cylindrical bore diameter variation

V_d2p - mean cylindrical bore diameter variation

D - nominal outside diameter

∆_Ds - deviation of single outside diameter from the nominal dimension

∆_Dmp - mean outside cylindrical surface diameter deviation in single plane

V_Dp - single outside cylindrical surface diameter variation in single radial plane

V_Dmp - mean outside cylindrical surface diameter variation

B  - inner ring nominal width

T  - total nominal width of tapered roller bearings

T₁ - nominal effective width of cup sub-unit

T₂ - nominal effective width of cone sub-unit

∆_Bs - nominal effective width of cone sub-unit

∆_Cs - outer ring single width deviation

∆_Ts - bearing single width deviation (total)

∆_T1s - cone sub-unit effective width deviation

∆_T2s  - cup sub-unit effective width deviation

C - outer ring nominal width

V_Bs - inner ring single width variation

V_Cs - outer ring single width variation

K_ia - radial runout of assembled bearing inner ring

K_ea - radial runout of assembled bearing outer ring

S_i - shaft washer raceway axial runout

S_e - housing washer raceway axial runout

S_ia - inner ring flat seat face axial runout of assembled bearing

S_ea -outer ring flat seat face axial runout of assembled bearing

S_d - flat seat face axial runout

S_D - runout of outside cylindrical surface towards outer ring face

S_s  - runout of supporting face towards seat face for single row tapered roller bearings