SKF 71948 ACD/P4AL Angular contact ball bearings, super-precision

SKF 71948 ACD/P4AL Angular contact ball bearings, super-precision
Angular contact ball bearings, super-precision

Tolerances: P4A, P4, PA9A, P2, Chamfer dimensionsRecommended shaft and housing fits: shafts, housingsValues for ISO tolerance classes: shafts, housingsSpeed dependent initial grease fill →Initial grease fillClamping and fitting forces: D design, E design, B design

Designation suffixes H, H1, L and L1identify variants for direct oil-air lubrication(→Variants).

d		240	mm
D		320	mm
B		38	mm
d1		264.7	mm
d2		264.7	mm
D1		295.3	mm
b		3.5	mm
C1		20.9	mm
C2		7.1	mm
C3		5.45	mm
r1,2	min.	2.1	mm
r3,4	min.	1	mm
a		84.5	mm

Abutment dimensions

da	min.	251	mm
db	min.	251	mm
Da	max.	309	mm
Db	max.	315	mm
ra	max.	2	mm
rb	max.	1	mm
dn		271.4	mm

Calculation data

Basic dynamic load rating	C		216	kN
Basic static load rating	C0		305	kN
Fatigue load limit	Pu		7.8	kN
Attainable speed for grease lubrication			3200	r/min
Attainable speed for oil-air lubrication			4800	r/min
Ball diameter	Dw		25.4	mm
Number of balls	z		31
Reference grease quantity	Gref		93	cm³
Preload and stiffness (back-to-back, face-to-face)
Preload class A	GA		1350	N
Static axial stiffness, preload class A			584	N/µm
Preload class B	GB		2700	N
Static axial stiffness, preload class B			767	N/µm
Preload class C	GC		5400	N
Static axial stiffness, preload class C			1029	N/µm
Preload class D	GD		10800	N
Static axial stiffness, preload class D			1412	N/µm
Calculation factors
Calculation factor	f		1.32
Calculation factor	f1		0.98
Calculation factor	f2A		1
Calculation factor	f2B		1.04
Calculation factor	f2C		1.08
Calculation factor	f2D		1.14
Calculation factor	fHC		1
Calculation factor	e		0.68
Calculation factor (single, tandem)	Y2		0.87
Calculation factor (single, tandem)	Y0		0.38
Calculation factor (single, tandem)	X2		0.41
Calculation factor (back-to-back, face-to-face)	Y1		0.92
Calculation factor (back-to-back, face-to-face)	Y2		1.41
Calculation factor (back-to-back, face-to-face)	Y0		0.76
Calculation factor (back-to-back, face-to-face)	X2		0.67

Mass

Mass bearing

8.5

kg

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