Rigidity

Content

Calculation of the radial or axial displacement

✎	*Roller bearings are more rigid than ball bearings*

The rigidity ╳
Resistance to displacement under load in the elastic deformation area, dependent on bearing clearance and bearing type

See Deflection of a rolling bearing ╳
Ready-to-fit machine element, often defined in standards, for transmitting movements, loads and tilting moments with a high level of efficiency; rolling bearings consist of rolling elements, cages and raceways on rings, guideways or carriages as well as lubricant and, if necessary, seals and accessories is dependent on the bearing type, size and operating clearance. The rigidity ╳
Resistance to displacement under load in the elastic deformation area, dependent on bearing clearance and bearing type

See Deflection increases with the number of rolling elements ╳
The number of rolling elements in one row of a bearing in the direction of movement supporting the load. Due to the line contact between the rolling elements and raceways, it is higher in roller bearings than in ball bearings. ➤ Figure 1 shows typical characteristic curves for the radial deflection ╳
The ability to absorb energy over a certain distance, to store this completely or partially as deformation energy and to release the energy when the load is removed (hysteresis) of various bearings with the same bore diameter.

Figure 1
Radial deflection ╳
The ability to absorb energy over a certain distance, to store this completely or partially as deformation energy and to release the energy when the load is removed (hysteresis) of various radial bearings of bore diameter d = 50 mm

δ_r = radial deflection
F_r = radial load

Calculation of the radial or axial displacement

✎	Progressive deflection ╳ The ability to absorb energy over a certain distance, to store this completely or partially as deformation energy and to release the energy when the load is removed (hysteresis) rate

Rolling bearings have a progressive deflection ╳
The ability to absorb energy over a certain distance, to store this completely or partially as deformation energy and to release the energy when the load is removed (hysteresis) rate. The displacement values for needle and cylindrical roller bearings can be determined using approximation equations ➤ Equation 1 and ➤ Equation 2.

The equations are valid for bearings without misalignment ╳
Deviation of an actual line from a theoretical ideal line, for example a bearing axis from the shaft axis; may be due to machining, flexing of shaft or deformation of housing. and with a rigid surrounding structure. In axial bearings, a concentrically acting load ╳
Load which, for example, is to be supported at a friction point. Also strain from pressure and/or heat.

See Contact surface is assumed.

Radial displacement

Axial displacement

Rigidity parameter

Legend

c_s	N^0,84/μm
Rigidity parameter
d	mm
Bearing bore diameter
δ_r	μm
Radial displacement between shaft axis and centre of bore ➤ Figure 2
δ_a	μm
Axial displacement between shaft locating washer and housing ╳ See Mounting dimenstions locating washer ➤ Figure 3
s	μm
Radial operating clearance ╳ The amount by which the bearing rings in a fitted bearing can be moved in the radial or axial direction from one extreme position to the other. of fitted, unloaded bearing
F_r	N
Radial load
F_a	N
Axial load
F_aV	N
Axial preload ╳ Force due to negative operating clearance or negative bearing clearance in rolling bearings force
K_c
Factor for determining the rigidity ╳ Resistance to displacement under load in the elastic deformation area, dependent on bearing clearance and bearing type See Deflection parameter ➤ Table 1.

Figure 2
Radial cylindrical roller bearings, radial displacement

δ_r = radial displacement
F_r = radial load

Figure 3
Axial cylindrical roller bearing, axial displacement

δ_a = axial displacement
F_a = axial load
F_aV = axial preload ╳
Force due to negative operating clearance or negative bearing clearance in rolling bearings force

Table 1
Factor K_c

Bearing series	Factor K_c	Series	Factor K_c
SL1818	12,8	K811, 811, K812, 812	36,7
SL1829, SL1830, SL1923	16	K893, 893, K894, 894	59,7
SL1850, SL0148, SL0248, SL0249	29,2	NJ2..-E	11,1
NA48	24,9	NJ3..-E	11,3
NA49	23,5	NJ22..-E	15,4
NA69	37,3	NJ23..-E	16,9
NKIS	21,3	NU10	9,5
NKI	4,4 · B^0,8/d^0,2	NU19	11,3
HK, BK	4,2 · C^0,8/d^0,2	NN30..-AS-K	18,6

This simplified calculation cannot be applied to other bearing types. The displacement and rigidity ╳
Resistance to displacement under load in the elastic deformation area, dependent on bearing clearance and bearing type

See Deflection at the operating point can be determined using the calculation program ╳
See INA EDP program BEARINX.