Bearing Shaft and Housing Installation Tolerances

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Bearing Shaft and Housing Installation Tolerances

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Tolerances, Engineering Design & Limits & Fits

Bearing Shaft and Housing Installation Tolerances

Size and fit tolerances for bearing mating shafts and housing are provided within the tables below are defined by ISO tolerances for shafts and housings (ISO 286) in conjunction with the tolerances Δdmp for the bore and ΔDmp for the outside diameter of the bearings per. (DIN 620).

The tables provided are design recommendation and should not supercede ABEC, ISO or OEM recommended fits and tolerances.

Tolerance zones amd variability

The ISO tolerances are defined in the form of tolerance zones. They are determined by their position relative to the zero line (= tolerance position) and their size (= tolerance grade, see ISO 286). The tolerance position is indicated by letters (upper case for housings, lower case for shafts). For a schematic representation of the most common rolling bearing fits.

The tables as below contain recommendations for the selection of shaft and housing tolerances that are valid for normal fitting and operating conditions.

Tolerance specification deviations are possible if particular requirements apply, for example in relation to running accuracy, smooth running or operating temperature. Increased running accuracies thus require closer tolerances such as tolerance grade 5 instead of 6. If the inner ring is warmer than the shaft during operation, the seating may loosen to an impermissible extent. A tighter fit must then be selected, for example m6 instead of k6.

In such cases, the question of fits can only be resolved by a compromise. The individual requirements must be weighed against each other and those fulfilled that give the best overall solution.

Roller Bearing Fits and Tolerances Designations
(Click on image to enlarge)

Zero line (Line-to-Line Fit)
Nominal diameter
Loose fit
Transition fit
Tight fit
Shaft diameter
Housing bore
ΔDmp = tolerance for bearing outside diameter
Δdmp = tolerance for bearing bore

Shaft tolerances for radial bearings with cylindrical bore

Condition of rotation	Bearing type	Shaft diameter mm	Displacement facility Load	Tolerance zone
Point load on inner ring	Ball bearings, roller bearings	All sizes	Inner ring easily displaced	g6 (g5)
	Ball bearings, roller bearings	All sizes	Inner ring not easily displaced, angular contact ball bearings and tapered roller bearings with adjusted inner ring	h6 (j6)
	Needle roller bearings	All sizes	Non-locating bearing	h6 (g6)1)
Circumferential load on inner ring or indeterminate load direction	Ball bearings	up to 50	Normal loads²	j6 (j5)
		50 to 100	Low loads³	j6 (j5)
		50 to 100	Normal and high loads4)	k6 (k5)
		100 to 200	Low loads²	k6 (m6)
		100 to 200	Normal and high loads⁵	m6 (m5)
		over 200	Low loads	m6 (m5)
		over 200	Normal and high loads	n6 (n5)
	Roller bearings	up to 60	Low loads	j6 (j5)
		up to 60	Normal and high loads	k6 (k5)
		60 to 200	Low loads	k6 (k5)
			Normal loads	m6 (m5)
			High loads	n6 (n5)
		200 to 500	Normal loads	m6 (n6)
		200 to 500	High loads, shocks	p6
		over 500	Normal loads	n6 (p6)
		over 500	High loads	p6
	Needle roller bearings	up to 50	Low loads	k6
		up to 50	Normal and high loads	m6
		50 to 120	Low loads	m6
		50 to 120	Normal and high loads	n6
		120 to 250	Low loads	n6
		120 to 250	Normal and high loads	p6
		250 to 400	Low loads	p6
		250 to 400	Normal and high loads	r6
		400 to 500	Low loads	r6
		400 to 500	Normal and high loads	s6
		over 500	Low loads	r6
		over 500	Normal and high loads	s6

For easier fitting.
C/P ＞ 10
C/P ＞ 12
C/P ＜ 12
C/P ＜ 10

Shaft tolerances for axial bearings

Load	Bearing type	Shaft diameter	Operating conditions	Tolerance zone
Axial load	Axial deep groove ball bearings	All sizes	-	j6
	Axial deep groove ball bearings, double direction		-	k6
	Axial cylindrical roller bearings with shaft locating washer		-	h6 (j6)
	Axial cylindrical roller and cage assemblies		-	h8
Combined load	Axial spherical roller bearings	All sizes	Point load on shaft locating washer	j6
		up to 200 mm	Circumferential load on shaft locating washer	j6 (k6)
		over 200 mm	Circumferential load on shaft locating washer	k6 (m6)

Housing tolerances radial bearings

Condition of rotation	Displacement facility Load	Operating conditions	Tolerance zone
Point load on outer ring	Outer ring easily displaced, housing un split	The tolerance grade is determined by the running accuracy required	H7 (H6)1)
	Outer ring easily displaced, housing split		H8 (H7)
	Outer ring not easily displaced, housing un split	High running accuracy required	H6 (J6)
	Outer ring not easily displaced, angular contact ball bearings and tapered roller bearings with adjusted outer ring Housing split	Normal running accuracy	H7 (J7)
	Outer ring easily displaced	Heat input via shaft	G72)
Circumferential load on outer ring or indeterminate load direction	Low loads, outer ring cannot be displaced	For high running accuracy requirements: K6, M6, N6 and P6	K7 (K6)
	Normal loads, shocks, outer ring cannot be displaced		M7 (M6)
	High loads, shocks (C/P ＜ 6), outer ring cannot be displaced		N7 (N6)
	High loads, severe shocks, thin-walled housing, outer ring cannot be displaced		P7 (P6)

1, G7 for housings made from flake graphite cast iron GG, if bearing outside diameter D ＞ 250 mm and temperature difference between outer ring and housing ＞ 10 K.

2, F7 for housings made from flake graphite cast iron GG, if bearing outside diameter D ＞ 250 mm and temperature difference between outer ring and housing ＞ 10 K.

Housing tolerances for axial bearings

Load	Bearing type	Operating conditions	Tolerance zone
Axial load	Axial deep groove ball bearings	Normal running accuracy High running accuracy	E8 H6
	Axial cylindrical roller bearings with housing locating washer	-	H7 (K7)
	Axial cylindrical roller and cage assemblies	-	H10
	Axial spherical roller bearings	Normal loads High loads	E8 G7
Combined loads Point load on housing locating washer	Axial spherical roller bearings	-	H7
Combined loads Circumferential load on housing locating washer	Axial spherical roller bearings	-	K7

Source

ISO 286
DIN 620