Cylindrical roller bearings

Cylindrical roller bearings with disc cage or with spacers

Cylindrical roller bearings with disc cage/with spacers are suitable where:

• Bearing arrangements are subjected to very high radial loads and higher speeds occur ➤ section, ➤ section
• High dynamic inertia forces are present
• Not only high radial forces but also axial loads from one direction must be supported by the bearing position (semi-locating bearing function) ➤ section
• High shock loads occur
• Thermally stable conditions are required in the bearing even at higher speeds
• The cages are subjected to high dynamic inertia forces; e. g. in vibratory machinery
• Axial displacements of the shaft relative to the housing must be compensated without constraint in the bearing
• The bearings should be separable for easier mounting; in vibratory machinery, for example, the bearing ring with circumferential load as well as the ring with point load should have a tight fit ➤ section, ➤ section

Cylindrical roller bearing with full complement bearing/standard cage/disc cage, comparison of speed and load carrying capacity nG = limiting speed Cr = basic dynamic load rating SL1923 = full complement cylindrical roller bearing NJ23 = cylindrical roller bearing with standard cage LSL1923 = cylindrical roller bearing with disc cage

Bearing design

Design variants

These cylindrical roller bearings are available as:

• type LSL1923 (bearing with disc cage) ➤ Figure
• type ZSL1923 (bearing with spacers) ➤ Figure
• special design for vibratory machinery ➤ link
• X-life bearings ➤ link

Basic design – standard range

LSL1923 and ZSL1923 correspond to dimension series 23

Cylindrical roller bearings with disc cage or with spacers are part of the group of radial roller bearings and correspond to dimension series 23. These single row bearings comprise radially split outer rings, removable inner rings, disc cages or spacers and cylindrical rollers. The rollers have profiled ends, i. e. they have a slight lateral curvature towards the ends. This modified line contact between the raceways and rolling elements prevents damaging edge stresses ➤ Figure. For mounting of the bearings, the inner ring can be removed.

Series LSL1923 – bearings with disc cage

Bearings with semi-locating bearing function

Cylindrical roller bearings LSL1923 have two rigid ribs on the outer ring and one rigid rib on the inner ring. An externally-guided flat brass disc cage prevents the rolling elements from coming into contact with each other during rolling ➤ Figure and ➤ section. The disc cage has pockets in which the rolling elements run. The rollers are guided between the ribs on the outer ring. The outer ring is axially split and held together by fasteners. Due to their design configuration, the bearings permit axial displacements of the shaft relative to the housing in one direction. In the opposite direction, they act as locating bearings. The maximum axial displacement s is given in the product tables.

Cylindrical roller bearing with disc cage Fr = radial load Fa = axial load Brass disc cage

Series ZSL1923 – bearings with spacers

Bearings with semi-locating bearing function

In the case of cylindrical roller bearings ZSL1923, plastic spacers prevent the rollers from coming into contact with each other during rolling ➤ Figure and ➤ section. The spacers are guided axially between the ribs on the outer ring. They are designed such that the rolling element set is self-retaining, so the outer ring with the rolling element set and the inner ring can be mounted separately from each other. Due to their design configuration, the bearings permit axial displacements of the shaft relative to the housing in one direction. In the opposite direction, they act as locating bearings. The maximum axial displacement s is given in the product tables.

Cylindrical roller bearing with spacers Fr = radial load Fa = axial load Plastic spacers

Special design of bearings LSL and ZSL for vibratory machinery

In addition to high basic dynamic load ratings C_r (and thus long rating life values), bearings for vibratory machinery must also be able to compensate or support considerable shaft tilting due to load or misalignment. The cylindrical roller bearings LSL and ZSL are therefore also available by agreement in the BIR design ➤ Table. In these bearings, the inner ring raceway is ground slightly spherical.

X-life premium quality

Many sizes of the bearings are also available as X-life bearings. These bearings exhibit considerably higher performance than comparable standard cylindrical roller bearings. This is achieved, for example, through the modified internal construction, the optimised contact geometry between the rollers and raceways, better surface quality and the optimised roller guidance and lubricant film formation.

Increased customer benefits due to X-life

These technical enhancements offer a range of advantages, such as:

• a more favourable load distribution in the bearing and thus a higher dynamic load carrying capacity of the bearings
• a higher fatigue limit load
• lower heat generation in the bearing
• lower lubricant consumption and therefore longer maintenance intervals if relubrication is carried out
• a measurably longer operating life of the bearings
• high operational security
• compact, environmentally-friendly bearing arrangements

Interchangeable with comparable standard bearings

Since X-life cylindrical roller bearings have the same dimensions as the corresponding standard bearings, the latter can be replaced without any problems by the higher-performance X-life bearings. The major advantages of X-life can therefore also be used for existing bearing arrangements with standard bearings.

Lower operating costs, higher machine availability

In conclusion, these advantages improve the overall cost-efficiency of the bearing position significantly and thus bring about a sustainable increase in the efficiency of the machine and equipment.

Suffix XL

X-life cylindrical roller bearings include the suffix XL in the designation ➤ section and ➤ link.

X-life indicates a high product performance density and thus a particularly significant benefit to the customer.

Load carrying capacity

Designed for high radial loads

Cylindrical roller bearings LSL and ZSL are used as semi-locating bearings. These bearings can support not only high radial forces but also axial forces in one direction; i. e. they can guide the shaft axially in one direction. Furthermore, they can withstand high shock loads, vibrations and accelerations.

Higher basic dynamic load ratings lead to an increase in basic rating life

Due to the internal construction, the bearings can acommodate more rolling elements than conventional cylindrical roller bearings. As a result, there is a significant increase in the basic dynamic and static load rating and thus the basic rating life compared with conventional cylindrical roller bearings. ➤ Figure shows a comparison of the basic dynamic load rating C_r between a cylindrical roller bearing NJ2324 with a conventional cage, a bearing with a disc cage and a bearing with spacers. The advantage in basic dynamic load rating of approx. 14% gives an increase in the basic load rating of approx. 55% ➤ Figure.

Comparison of basic dynamic load ratings – conventional cylindrical roller bearing NJ2324 with LSL192324 and ZSL192324

Comparison of basic percentage rating life – conventional cylindrical roller bearing NJ2324 with LSL192324 and ZSL192324

Higher axial load carrying capacity of bearings with toroidal crowned roller end face

Neither wear nor fatigue occurs on the rib contact running and roller end faces

In the case of cylindrical roller bearings with toroidal crowned rollers (TB design), the axial load carrying capacity has been significantly improved with the aid of new calculation and manufacturing methods. A special curvature of the roller end faces facilitates optimum contact ­conditions between the rollers and ribs ➤ Figure. As a result, the axial contact pressures on the rib are significantly minimised and a lubricant film capable of supporting higher loads is formed. Under standard ­operating conditions, this completely eliminates wear and fatigue at the rib contact running and roller end faces. In addition, the frictional torque is reduced by up to 50%. The bearing temperature during operation is therefore significantly lower. Bearings of the toroidal crowned design are available for a bore diameter of, or larger than, d = 90 mm ➤ dimension table.

Contact geometry of roller end face/rib face – modified roller end faces Cylindrical roller with inner ring Detail (representation not to scale) End of roller Rib

Load ratio F_a/F_r

Ratio F_a/F_r ≦ 0,4 or 0,6

The bearings can support axial loads on one side by means of the ribs on the inner and outer ring ➤ Figure. In order to ensure problem-free running (tilting of the rollers is prevented), they must always be subjected to radial load at the same time as axial load. The ratio F_a/F_r must not exceed the value 0,4. For bearings with toroidal roller ends (TB design), values up to 0,6 are permissible.

Continuous axial loading without simultaneous radial loading is not permissible.

Permissible axial load

Influencing factors on the axial load carrying capacity

Axial loads are supported by the bearing ribs and the roller end faces ➤ Figure and ➤ Figure. The axial load carrying capacity of the bearing is therefore essentially dependent on:

• the size of the sliding surfaces between the ribs and the end faces of the rolling elements
• the sliding velocity at the ribs
• the lubrication of the contact surfaces
• tilting of the bearing
• friction

Force flow under axial load – semi‑locating bearing LSL1923

Calculation of permissible axial load – cylindrical rollers with conventional roller ends

Bearings with standard roller ends

The permissible axial load F_{a per} can be calculated from the hydrodynamic load carrying capacity of the contact ➤ Equation.

Permissible axial load – bearings of standard design

Legend

Fa per	N	Permissible continuous axial load. In order to prevent unacceptably high temperatures in the bearing, Fa per must not be exceeded
Fa max	N	Maximum continuous axial load in relation to rib fracture. In order to prevent unacceptably high pressures at the contact surfaces, Fa max must not be exceeded
kS	-	Factor as a function of lubrication method ➤ Table. The factor takes into consideration the lubrication method used for the bearing. The better the lubrication and in particular the heat dissipation, the higher the permissible axial load
kB	-	Factor as a function of the bearing series, kB = 28
dM	mm	Mean bearing diameter dM = (D + d)/2 ➤ link
n	min-1	Operating speed

Factor k_S

Lubrication method	Factor kS
	from	up to
Minimal heat dissipation, drip feed oil lubrication, oil mist lubrication, low operating viscosity (ν ＜ 0,5 · ν1)	7,5	10
Poor heat dissipation, oil sump lubrication, oil spray lubrication, low oil flow	10	15
Good heat dissipation, recirculating oil lubrication (pressurised oil lubrication)	12	18
Very good heat dissipation, recirculating oil lubrication with oil cooling, high operating viscosity (ν ＞ 2 · ν1)	16	24

The precondition for these k_S values is an operating viscosity of the lubricant of at least the reference viscosity ν₁ in accordance with DIN ISO 281:2010.

Doped lubricating oils should be used, such as CLP (DIN 51517) and HLP (DIN 51524) of ISO-VG-grades 32 to 460 and ATF oils (DIN 51502) and transmission oils (DIN 51512) of SAE viscosity grades 75W to 140W.

Calculation of permissible axial load – cylindrical rollers with toroidal crowned roller ends

Higher axial loads possible

For bearings with toroidal roller ends, the permissible axial loads are 50% higher ➤ Equation.

Permissible axial load – bearings of TB design

Calculation of maximum permissible axial load

For bearings with rollers of the standard or TB design, the maximum permissible axial load F_{a max} ➤ Equation is calculated from the rib strength and the security against wear. This must not be exceeded, even if F_{a per} gives higher values ➤ Equation.

Maximum axial load – bearings of standard and TB design

Permissible axial load

Axial load under shaft deflection

Permissible axial load under shaft deflection of up to 2′

Under considerable shaft deflection, the shaft shoulder presses against the inner ring rib. In combination with the active axial load, this can lead to high alternating loading of the inner ring ribs. Under a shaft deflection of up to 2′, the permissible axial load can be estimated ➤ Equation.

If more severe tilting is present, a separate strength analysis is required. In this case, please contact Schaeffler.

Axial load under misalignment

Legend

Fas

N

Permissible axial load under misalignment

Compensation of angular misalignments

Angular deviations are misalignments between the inner and outer ring

The permissible misalignment between the inner ring and outer ring is influenced by the internal bearing construction, the operating clearance, the forces acting on the bearings etc. Due to these complex relationships, it is not possible to give generally valid absolute values here. However, misalignments (angular deviations) between the inner ring and outer ring always have an effect on the running noise and the operating life of the bearings.

Permissible tilting

The permissible guide value at which, based on experience, there is no significant reduction in operating life is 3′.

Scope of value

The value applies to:

• bearing arrangements with static misalignment (consistent position of the shaft and housing axis)
• bearings that are not required to perform an axial guidance function
• bearings subjected to small loads (with C_0r/P ≧ 5)

Checking by means of the calculation program BEARINX is recommended in all cases. If there is any uncertainty regarding possible misalignment, please consult Schaeffler.

Lubrication

Oil or grease lubrication is possible

The cylindrical roller bearings are not greased. They must be lubricated with oil or grease.

Pay attention to the compatibility of the lubricant with plastic

When using bearings with plastic spacers, compatibility between the lubricant and the cage material must be ensured if synthetic oils, lubricating greases with a synthetic oil base or lubricants containing a high proportion of EP additives are used.

If there is any uncertainty regarding the suitability of the selected lubricant for the application, please consult Schaeffler or the lubricant manufacturer.

Observe oil change intervals

Aged oil and additives in the oil can impair the operating life of plastics at high temperatures. As a result, stipulated oil change intervals must be strictly observed.

Sealing

Providing additional seals in the adjacent construction

The bearings are not sealed; i. e. sealing of the bearing position must be carried out in the adjacent construction. This must reliably prevent:

• moisture and contaminants from entering the bearing
• the egress of lubricant from the bearing

Speeds

Limiting speeds and reference speeds in the product tables

The product tables give two speeds for most bearings:

• the kinematic limiting speed n_G
• the thermal speed rating n_ϑr

Limiting speeds

The limiting speed n_G is the kinematically permissible speed of the bearing. Even under favourable mounting and operating conditions, this value should not be exceeded without prior consultation with Schaeffler ➤ link.

Reference speeds

n_ϑr is used to calculate n_ϑ

The thermal speed rating n_ϑr is not an application-oriented speed limit, but is a calculated ancillary value for determining the thermally safe operating speed n_ϑ ➤ link.

Noise

The Schaeffler Noise Index (SGI) has been developed as a new feature for comparing the noise level of different bearing types and series. As a result, a noise evaluation of rolling bearings can now be carried out for the first time.

Schaeffler Noise Index

The SGI value is based on the maximum permissible noise level of a bearing in accordance with internal standards, which is calculated on the basis of ISO 15242. In order that different bearing types and series can be compared, the SGI value is plotted against the basic static load rating C₀.

This permits direct comparisons between bearings with the same load carrying capacity. The upper limit value is given in each of the diagrams. This means that the average noise level of the bearings is lower than illustrated in the diagram.

The Schaeffler Noise Index is an additional performance characteristic in the selection of bearings for noise-sensitive applications. The specific suitability of a bearing for an application in terms of installation space, load carrying capacity or speed limit for example, must be checked independently of this.

Schaeffler Noise Index for cylindrical roller bearings with spacers SGI = Schaeffler Noise Index C0 = basic static load rating

Temperature range

Limiting values

The operating temperature of the bearings is limited by:

• the dimensional stability of the bearing rings and cylindrical rollers
• the cage (disc cage or spacers)
• the lubricant

Possible operating temperatures of bearings ➤ Table.

Permissible temperature ranges

Operating temperature	Cylindrical roller bearings with disc cage or with spacers
	–30 °C to +120 °C

In the event of anticipated temperatures which lie outside the stated values, please contact Schaeffler.

Cages

Bearings with a disc cage or spacers are suitable for applications with high dynamic inertia forces

In addition to the actual task of a cage, which is to hold rolling elements apart from each other, a cage designed for vibrations (e. g. for use in vibratory machinery) must be able to support, on a fatigue-resistant basis, principally the inertia forces that act on the cage due to its own mass, as well as the inertia forces of the rolling elements that act directly on the cage pockets. Since these applications also call for very high basic load ratings, conventional cages can only support this requirement under very limited conditions. As a result, bearings with a brass disc cage or plastic spacers have been developed, which constitute a transition from full complement bearings to conventional cage bearings.

Disc cage

Rolling elements are held by the cage

This cage is designed as a flat disc ➤ Figure. Facing towards the inside diameter are rolling element pockets that support the rolling elements. The cage inside diameter is extended downwards to below the pitch circle line. This gives retention of the rolling elements, i. e. the inner ring can be mounted separately from the rest of the bearing. Facing the outside diameter, the disc cage is seated concentrically between the ribs in a slot in the outer ring.

Rollers and solid brass disc cage

Spacers

Lower bearing frictional torque due to the geometry of the spacers

The plastic spacers were developed specially for the series ZSL1923 ➤ Figure. They are designed such that the rolling element set is self-retaining, i. e. the bearing and inner ring can be mounted separately from each other.

Rollers and plastic spacers

Internal clearance

Radial internal clearance

The standard is CN

As standard, cylindrical roller bearings with disc cage or with spacers have the radial internal clearance CN (normal) ➤ Table. CN is not stated in the designation.

When used in vibratory machinery, both bearing rings have a tight fit. As a result, and due to the temperature differential between the inner ring and outer ring, the internal clearance C4 is generally necessary. As standard, bearings for vibratory machinery therefore have this internal clearance group.

Certain sizes are also available by agreement with the larger internal clearance C3, C4 and C5 ➤ Table.

The values for radial internal clearance correspond to DIN 620-4:2004 (ISO 5753-1:2009) ➤ Table. They are valid for bearings which are free from load and measurement forces (without elastic deformation).

Radial internal clearance of cylindrical roller bearings with disc cage or with spacers

Nominal bore diameter		Radial internal clearance
d		CN (Group N)		C3 (Group 3)		C4 (Group 4)		C5 (Group 5)
mm		μm		μm		μm		μm
over	incl.	min.	max.	min.	max.	min.	max.	min.	max.
‒	24	20	45	35	60	50	75	65	90
24	30	20	45	35	60	50	75	70	95
30	40	25	50	45	70	60	85	80	105
40	50	30	60	50	80	70	100	95	125
50	65	40	70	60	90	80	110	110	140
65	80	40	75	65	100	90	125	130	165
80	100	50	85	75	110	105	140	155	190
100	120	50	90	85	125	125	165	180	200
120	140	60	105	100	145	145	190	200	245
140	160	70	120	115	165	165	215	225	275
160	180	75	125	120	170	170	220	250	300
180	200	90	145	140	195	195	250	275	330
200	225	105	165	160	220	220	280	305	365
225	250	110	175	170	235	235	300	330	395
250	280	125	195	190	260	260	330	370	440
280	315	130	205	200	275	275	350	410	485

Dimensions, tolerances

Dimension standards

The main dimensions of cylindrical roller bearings correspond to ISO 15:2017 (DIN 616:2000 and DIN 5412-1:2005).

Chamfer dimensions

The limiting dimensions for chamfer dimensions correspond to DIN 620‑6:2004. Overview and limiting values ➤ section. Nominal value of chamfer dimension ➤ link.

Tolerances

The dimensional and running tolerances correspond to the tolerance class Normal in accordance with ISO 492:2014. Tolerance values in accordance with ISO 492 ➤ link.

Suffixes

For a description of the suffixes used in this chapter ➤ Table and medias interchange http://www.schaeffler.de/std/1B69.

Suffixes and corresponding descriptions

Suffix	Description of suffix
BIR	Inner ring raceway ground slightly spherical	Available by agreement
BR	Black oxide coated	Available by agreement
C3	Radial internal clearance C3 (larger than normal)	Available by agreement
C4	Radial internal clearance C4 (larger than C3)	Available by agreement
C5	Radial internal clearance C5 (larger than C4)	Available by agreement
TB	Bearing with increased axial load carrying capacity	Standard dependent on bearing size
XL	X-life bearing	Standard dependent on bearing size

Structure of bearing designation

Examples of composition of bearing designation

The designation of bearings follows a set model. Examples ➤ Figure and ➤ Figure. The composition of designations is subject to DIN 623‑1 ➤ link.

Cylindrical roller bearing with disc cage: designation structure

Cylindrical roller bearings with spacers, internal clearance C3: designation structure

Dimensioning

Equivalent dynamic bearing load

P = F_r under purely radial load of constant magnitude and direction

The basic rating life equation L = (C_r/P)^p used in the dimensioning of bearings under dynamic load assumes a load of constant magnitude and direction. In radial bearings, this is a purely radial load F_r. If this condition is met, the bearing load F_r is used in the rating life equation for P (P = F_r).

Cylindrical roller bearings with non-locating bearing function

P = F_r

Non-locating bearings can only support radial loads. For these bearings ➤ Equation.

Equivalent dynamic load

Cylindrical roller bearings with semi-locating or locating bearing function

P is a substitute force for combined load and various load cases

If the condition described above is not met, i. e. if in addition to the radial force F_r there is also an axial force F_a, a constant radial force must first be determined for the rating life calculation that (in relation to the rating life) represents an equivalent load. This force is known as the equivalent dynamic bearing load P.

F_a/F_r ≦ e or F_a/F_r ＞ e

The calculation of P is dependent on the load ratio F_a/F_r and the calculation factors e and Y ➤ Equation and ➤ Equation.

Equivalent dynamic load

Equivalent dynamic load

Legend

P	N	Equivalent dynamic bearing load
Fr	N	Radial load
Fa	N	Axial load
e	-	Factor, e = 0,3
Y	-	Factor, Y = 0,4

Equivalent static bearing load

P₀ = F_0r

For cylindrical roller bearings subjected to static load ➤ Equation.

Equivalent static load

Legend

P0	N	Equivalent static bearing load
F0r	N	Largest radial load present (maximum load)

Static load safety factor

S₀ = C₀/P₀

In addition to the basic rating life L (L_10h), it is also always necessary to check the static load safety factor S₀ ➤ Equation.

Static load safety factor

Legend

S0	-	Static load safety factor
C0	N	Basic static load rating
P0	N	Equivalent static bearing load

Minimum load

In order to prevent slippage damage, a minimum radial load of P ＞ C_0r/60 is necessary during continuous operation

In order that no slippage occurs between the contact partners, the cylindrical roller bearings must be constantly subjected to a sufficiently high radial load. For continuous operation, experience shows that a minimum radial load of the order of P ＞ C_0r/60 is necessary. In most cases, however, the radial load is already higher than the requisite minimum load due to the weight of the supported parts and the external forces.

If the minimum radial load is lower than indicated above, please consult Schaeffler.

Design of bearing arrangements

Support bearing rings over their entire circumference and width

In order to allow full utilisation of the load carrying capacity of the bearings and thus also achieve the requisite rating life, the bearing rings must be rigidly and uniformly supported by means of contact surfaces over their entire circumference and over the entire width of the raceway. Support can be provided by means of a cylindrical seating surface. The seating and contact surfaces should not be interrupted by grooves, holes or other recesses. The accuracy of mating parts must meet specific requirements ➤ Table to ➤ Table.

Radial location

For secure radial location, tight fits are necessary

In addition to supporting the rings adequately, the bearings must also be securely located in a radial direction, to prevent creep of the bearing rings on the mating parts under load. This is generally achieved by means of tight fits between the bearing rings and the mating parts. If the rings are not secured adequately or correctly, this can cause severe damage to the bearings and adjacent machine parts. Influencing factors, such as the conditions of rotation, magnitude of the load, internal clearance, temperature conditions, design of the mating parts and the mounting and dismounting options must be taken into consideration in the selection of fits.

If shock type loads occur, tight fits (transition fit or interference fit) are required to prevent the rings from coming loose at any point. Clearance, transition or interference fits ➤ Table.

The following information provided in Technical principles must be taken into consideration in the design of bearing arrangements:

• conditions of rotation ➤ link
• tolerance classes for cylindrical shaft seats (radial bearings) ➤ link
• shaft fits ➤ link
• tolerance classes for bearing seats in housings (radial bearings) ➤ link
• housing fits ➤ link

Axial location

The bearings must also be securely located in an axial direction

As a tight fit alone is not normally sufficient to also locate the bearing rings securely on the shaft and in the housing bore in an axial direction, this must usually be achieved by means of an additional axial location or retention method. The axial location of the bearing rings must be matched to the type of bearing arrangement. Shaft and housing shoulders, housing covers, nuts, spacer rings, retaining rings, adapter and withdrawal sleeves etc. are generally suitable; example ➤ Figure.

Dimensional, geometrical and running accuracy of cylindrical bearing seats

A minimum of IT6 should be provided for the shaft seat and a minimum of IT7 for the housing seat

The accuracy of the cylindrical bearing seat on the shaft and in the housing should correspond to the accuracy of the bearing used. For cylindrical roller bearings with the tolerance class Normal, the shaft seat should correspond to a minimum of standard tolerance grade IT6 and the housing seat to a minimum of IT7. Guide values for the geometrical and positional tolerances of the bearing seating surfaces ➤ Table, tolerances t₁ to t₃ in accordance with ➤ Figure. Numerical values for IT grades ➤ Table.

Guide values for the geometrical and positional tolerances of bearing seating surfaces

Bearing tolerance class		Bearing seating surface	Standard tolerance grades to ISO 286-1 (IT grades)
to ISO 492	to DIN 620		Diameter tolerance	Roundness tolerance	Parallelism tolerance	Total axial runout tolerance of abutment shoulder
				t1	t2	t3
Normal	PN (P0)	Shaft	IT6 (IT5)	Circumferential load IT4/2	Circumferential load IT4/2	IT4
		Shaft	IT6 (IT5)	Point load IT5/2	Point load IT5/2	IT4
		Housing	IT7 (IT6)	Circumferential load IT5/2	Circumferential load IT5/2	IT5
		Housing	IT7 (IT6)	Point load IT6/2	Point load IT6/2	IT5

Numerical values for ISO standard tolerances (IT grades) to ISO 286-1:2010

IT grade	Nominal dimension in mm
	over	18	30	50	80	120	180	250
	incl.	30	50	80	120	180	250	315
	Values in μm
IT4		6	7	8	10	12	14	16
IT5		9	11	13	15	18	20	23
IT6		13	16	19	22	25	29	32
IT7		21	25	30	35	40	46	52

Roughness of cylindrical bearing seating surfaces

Ra must not be too high

The roughness of the bearing seats must be matched to the tolerance class of the bearings. The mean roughness value Ra must not be too high, in order to maintain the interference loss within limits. The shafts must be ground, while the bores must be precision turned. Guide values as a function of the IT grade of bearing seating surfaces ➤ Table.

Roughness values for cylindrical bearing seating surfaces – guide values

Nominal diameter of the bearing seat d (D)		Recommended mean roughness value for ground bearing seats Ramax
mm		μm
		Diameter tolerance (IT grade)
over	incl.	IT7	IT6	IT5	IT4
‒	80	1,6	0,8	0,4	0,2
80	500	1,6	1,6	0,8	0,4

Mounting dimensions for the contact surfaces of bearing rings

The contact surfaces for the rings must be of sufficient height

The mounting dimensions of the shaft and housing shoulders, and spacer rings etc., must ensure that the contact surfaces for the bearing rings are of sufficient height. The transition from the bearing seat to the abutment shoulder must be designed with rounding to DIN 5418:1993 or an undercut to DIN 509:2006. Proven mounting dimensions for the radii and diameters of abutment shoulders are given in the product tables ➤ link and ➤ Figure. These dimensions are limiting dimensions (maximum or minimum dimensions); the actual values should not be higher or lower than specified.

Rib support in axially loaded bearings

Ribs under axial load must be supported over their entire height and entire circumference. The size and axial runout accuracy of the contact surfaces on the inner ring rib must be observed especially in the case of cylindrical roller bearings subjected to high loads, since these factors also influence the uniformity of the rib load and the running accuracy of the shaft. This means that the ribs may be subjected to damaging alternating stresses even in the case of very small misalignments. If the mounting dimensions indicated in the product tables are observed, the problems described can be reliably avoided ➤ Figure and ➤ link.

Support in semi-locating bearings

In semi-locating bearings, it is sufficient to support the bearing rings on one side, on the rib supporting the axial load ➤ Figure.

Support of the inner ring rib – bearing with disc cage LSL 1923 (semi-locating bearing) dc = recommended height of shaft shoulder with axially loaded rib Arrow = force flow

Mounting and dismounting

The mounting and dismounting options for cylindrical roller bearings, by thermal, hydraulic or mechanical methods, must be taken into consideration in the design of the bearing position.

As the bearings are not self-retaining, they are easy to mount

The cylindrical roller bearings LSL 1923 and ZSL 1923 are not self-retaining. As a result, the bearing parts can be mounted separately from each other ➤ section. This gives simplified mounting of the bearings, especially when the two bearing rings have a tight fit.

Schaeffler Mounting Handbook

Rolling bearings must be handled with great care

Rolling bearings are well-proven precision machine elements for the design of economical and reliable bearing arrangements, which offer high operational security. In order that these products can function correctly and achieve the envisaged operating life without detrimental effect, they must be handled with care.

The Schaeffler Mounting Handbook MH 1 gives comprehensive information about the correct storage, mounting, dismounting and maintenance of rotary rolling bearings http://www.schaeffler.de/std/1B68. It also provides information which should be observed by the designer, in relation to the mounting, dismounting and maintenance of bearings, in the original design of the bearing position. This book is available from Schaeffler on request.

Legal notice regarding data freshness

The further development of products may also result in technical changes to catalogue products

Of central interest to Schaeffler is the further development and optimisation of its products and the satisfaction of its customers. In order that you, as the customer, can keep yourself optimally informed about the progress that is being made here and with regard to the current technical status of the products, we publish any product changes which differ from the printed version in our electronic product catalogue.

We therefore reserve the right to make changes to the data and illus­trations in this catalogue. This catalogue reflects the status at the time of printing. More recent publications released by us (as printed or digital media) will automatically precede this catalogue if they involve the same subject. Therefore, please always use our electronic product catalogue to check whether more up-to-date information or modification notices exist for your desired product.

Further information

In addition to the data in this chapter, the following chapters in Technical principles must also be observed in the design of bearing arrangements:

• Determining the bearing size ➤ link
• Rigidity ➤ link
• Friction and increases in temperature ➤ link
• Speeds ➤ link
• Bearing data ➤ link
• Lubrication ➤ link
• Sealing ➤ link
• Design of bearing arrangements ➤ link
• Mounting and dismounting ➤ link