Tolerances and fitting suggestions

Tolerances

DURBAL heavy-duty rod ends and spherical plain bearings with metric or imperial dimensions are – unless stated otherwise – produced to the diameter and width tolerances specified in the DIN ISO standards. The dimension and tolerance symbols shown in the tables are explained below.

The following tolerances apply for DURBAL products:

  • Rod ends
  • Spherical plain bearings
  • Angular contact spherical plain bearing
  • Axial spherical plain bearing

DURBAL tolerances apply to bearing ring blanks which are neither divided nor opened. Depending on the surface treatment, these may deviate from the standard values. Spherical plain bearings with an open or divided outer ring may also be slightly uneven after opening up or dividing. However, the original roundness will be restored after installation in a housing with a bore hole with precise shape and dimensions and sufficient wall thickness. Reliable conclusions can therefore not be drawn on the precision of the dimensions of the outer rings solely on the basis of measurements on bearings which have not been installed. 


Dimension and tolerance symbols:

d
Bore hole diameter of the bearing

Δdmp
Deviation of the average bore hole diameter of the bearing from the target dimension

Vdp
Variation of the bore hole diameter in a plane (roundness)

Vdmp
Deviation of the average bore hole diameter (cylindricity)

ΔBs
Deviation of the width of an individual inner ring

D
Outer diameter of the bearing

ΔDmp
Deviation of the average outer diameter of the bearing from the target dimension

VDp
Variation of the outer diameter in a plane (roundness)

VDmp
Deviation of the average outer diameter (cylindricity)

ΔCs
Deviation of the width of an individual outer ring

T
Width or height of the bearing

ΔTs
Deviation of the width or height of the bearing from the target value


Fitting suggestions

The fit must be selected so that there is no movement between the joint ball bore and shaft, or between the outer ring of the bearing and the housing bore. Care must also be taken to ensure that excessively tight fits do not have an adverse effect on the bearing clearance.

Housing bore for the installation of spherical plain bearings

Series K
K7 / H7

Series E, G, W
M7 / K7

Shaft fits for spherical plain bearings and rod ends

Series K, W
k6 / h6

Series E, G
j6 / g6