Table of contents
Self-aligning ball bearings
- Bearing design
- Load carrying capacity
- Compensation of angular misalignments
- Lubrication
- Sealing
- Speeds
- Noise
- Temperature range
- Cages
- Internal clearance
- Dimensions, tolerances
- Suffixes
- Structure of bearing designation
- Dimensioning
- Minimum load
- Design of bearing arrangements
- Mounting and dismounting
- Legal notice regarding data freshness
- Further information
Self-aligning ball bearings
Self-aligning ball bearings are particularly suitable:
- if there is skewing between the outer and inner ring (for the compensation of angular misalignments) ➤ section
- for bearing arrangements with high radial loads ➤ section
- for higher speeds on account of their point contact, than barrel roller bearings with line contact
- where bearings with the above-mentioned characteristics are expected to run more quietly and at lower temperatures, even at high speeds
Self-aligning ball bearings: nG = limiting speed |
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Bearing design
Design variants
Self-aligning ball bearings are available as:
- bearings of basic design ➤ Figure
- bearings with extended inner ring and locating slot ➤ Figure
- bearings with adapter sleeve ➤ Figure
- bearings with ball projection ➤ Figure
Bearings of basic design
The outer ring has a curved raceway
Self-aligning ball bearings are double row, self-retaining radial ball bearings, which are part of the group of self-aligning bearings. The outer ring has a single concave raceway for the two rows of balls. As a result, the bearings permit the compensation of static and dynamic angular misalignments (skewing between the inner and outer ring) within certain limits ➤ section. The inner ring has two formed raceway grooves in which the rolling elements run. Solid cages made from polyamide PA66 or brass are used ➤ Table.
The bore is cylindrical or tapered
Bearings of basic design are supplied with a cylindrical bore; self-aligning ball bearings of series 12, 13, 22 and 23 are also available with a tapered bore ➤ Figure.
Bearings with a tapered bore have a bore taper of 1:12 and the suffix K ➤ Table.
Self-aligning ball bearings Fr = radial load Fa = axial load
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Bearings with extended inner ring and locating slot
Suitable for simple bearing arrangements
Self-aligning ball bearings of series 112 have an extended inner ring with cylindrical bore on both sides and a slot on one side of the inner ring ➤ Figure. These bearings are particularly suitable for simple bearing arrangements with conventional shafts. Due to the bearing bore tolerance J7, mounting and dismounting of this type is very simple. The slot is used to locate the bearings in an axial direction by means of a grub screw; ➤ Figure.
Self-aligning ball bearing Fr = radial load Fa = axial load
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Bearings with adapter sleeve
Ready-to-fit bearing mounting kits facilitate the ordering and mounting of self-aligning ball bearings
Complete bearing mounting kits are also available for use in locating self-aligning ball bearings with a tapered bore onto a cylindrical shaft journal. These units comprise the bearing, slotted adapter sleeve, tab washer and locknut (series 12..-K + H, 13..-K + H, 22..-K + H, 23..-K + H, 22..-K-2RS + H) ➤ Figure. Adapter sleeves allow bearings to be located on smooth and stepped shafts. The adapter sleeves must also be stated when placing the order. Ordering example ➤ Figure.
Self-aligning ball bearings Fr = radial load Fa = axial load
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Bearings with ball projection
The dimension C1 must be observed
In some self-aligning ball bearings with a brass cage (bearings with the suffix M), the balls project to a certain extent at the sides ➤ Figure.
The projection is marked C1 in the product tables. This must be taken into consideration when defining the dimensions for the adjacent parts.
Self-aligning ball bearing C1 = ball projection |
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Load carrying capacity
Suitable for high radial and low axial loads
In addition to high radial forces, self-aligning ball bearings also support low axial forces from both directions ➤ Figure to ➤ Figure. Due to the point contact with which the rolling bearings are in contact with the raceways, the radial load carrying capacity of the bearings is lower than for barrel roller bearings with line contact.
Axial load carrying capacity of bearings with adapter sleeve
Where bearings with adapter sleeves are located on a smooth shaft without a fixed stop (e. g. rigid shoulder), their axial load carrying capacity is dependent on the friction between the shaft and the sleeve.
If there is any doubt about the axial load carrying capacity of the location method, please consult Schaeffler.
Compensation of angular misalignments
Self-aligning ball bearings compensate dynamic and static angular misalignments
Due to the concave rolling element raceway in the outer ring, self-aligning ball bearings are capable of angular adjustment. As a result, they permit skewing between the outer and inner ring within certain limits, without causing damage to the bearings, and can thus compensate misalignments, shaft deflections and housing deformations.
Permissible adjustment angle
With a rotating inner ring, self-aligning ball bearings can swivel up to 4° from their central position
Under normal operating conditions and with a rotating inner ring, self‑aligning ball bearings can swivel up to 4° from their central position, whereas sealed bearings can swivel up to 1,5°. The extent to which these values can be used in practice is, however, essentially dependent on the design of the bearing arrangement.
If the outer ring rotates or the inner ring undergoes tumbling motion, the angular adjustment facility is considerably smaller. In such cases, please consult Schaeffler.
Lubrication
Greased bearings are maintenance-free
Sealed self-aligning ball bearings are lubricated with a high quality lithium soap grease with a mineral oil base, which has good anti-corrosion characteristics. The grease filling is measured so that it is sufficient for the entire life of the bearing. As a result, these bearings are maintenance‑free.
Do not wash greased bearings out prior to mounting. If mounting is carried out using thermal tools, the bearings should not be heated to a temperature in excess of +80 °C, taking account of the grease filling and seal material. If higher heating temperatures are required, it must be ensured that the permissible upper temperature limits for grease and seals are not exceeded. Schaeffler recommends the use of induction heating devices for heating purposes ➤ link.
Lubrication for ungreased bearings
Open bearings are not greased. They can be lubricated from the end faces using oil or grease.
Compatibility with plastic cages
When using bearings with plastic cages, 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.
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
Also available with lip seals
Self-aligning ball bearings of series 22 and 23 are also available with contact seals on both sides of the bearing ➤ Figure. The integration of such seals into the bearing provides a compact, economical and reliable solution for the sealing of bearing arrangements. In order that the highest possible sealing effect can still be achieved with minimum friction, the seal lips are in contact with the ground opposing running surface of the inner ring under light pressure. The sealing material used is the proven, oil-resistant and wear-resistant elastomer material NBR. Sealed self-aligning ball bearings have the suffix 2RS ➤ link.
Sealing can be achieved in the adjacent construction, if the bearings are open
In the case of unsealed bearings, sealing of the bearing position must be carried out in the adjacent construction. The sealing system should reliably prevent:
- moisture and contaminants from entering the bearing
- the egress of lubricant from the bearing
Speeds
Speeds in the product tables
The product tables give two speeds for most bearings:
- the kinematic limiting speed nG
- the thermal speed rating nϑr
Limiting speeds
The limiting speed nG 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.
The values given in the product tables are valid for oil lubrication in the case of bearings without seals and for grease lubrication where bearings are supplied greased and with seals.
Values for grease lubrication
For grease lubrication, 85% of the value stated in the product tables is permissible in each case.
Reference speeds
nϑr is used to calculate nϑ
The thermal speed rating nϑr is not an application-oriented speed limit, but is a calculated ancillary value for determining the thermally safe operating speed nϑ ➤ link.
Bearings with contact seals
For bearings with contact seals, no speed ratings are defined in accordance with DIN ISO 15312:2004. As a result, only the limiting speed nG is given in the product tables for these bearings.
Noise
Schaeffler Noise Index
The Schaeffler Noise Index (SGI) is not yet available for this bearing type ➤ link. The data for these bearing series will be introduced and updated in stages.
Temperature range
Limiting values
The operating temperature of the bearings is limited by:
- the dimensional stability of the bearing rings and rolling elements
- the cage
- the lubricant
- the seals
Possible operating temperatures of self-aligning ball bearings ➤ link.
Permissible temperature ranges
Operating temperature |
Open self-aligning ball bearings |
Sealed self-aligning |
|
---|---|---|---|
with brass cage |
with polyamide cage PA66 |
||
|
-30 °C to +150 °C |
-30 °C to +120 °C |
-30 °C to +100 °C, limited by the lubricant and seal material |
In the event of anticipated temperatures which lie outside the stated values, please contact Schaeffler.
Cages
Solid cages made from brass and polyamide PA66 are used as standard
Standard cages and additional cage designs for self-aligning ball bearings ➤ Table. Other cage designs are available by agreement. With such cages, however, suitability for high speeds and temperatures as well as the basic load ratings may differ from the values for the bearings with standard cages.
Cage, cage suffix, bore code
Bearing series |
Solid cage |
Solid brass cage |
|
---|---|---|---|
TVH |
M |
||
standard |
standard |
also available for |
|
Bore code |
|||
10 |
8 |
‒ |
‒ |
12 |
up to 18 |
from 19 |
‒ |
13 |
up to 13 |
from 14 |
03 |
22 |
up to 16, 18 |
17, from 19 |
12, 14 |
23 |
up to 13 |
from 14 |
05 to 10, 12, 13 |
112 |
04 to 12 |
‒ |
‒ |
Internal clearance
Radial internal clearance – bearings with cylindrical bore
The standard is CN
Self-aligning ball bearings with cylindrical bore are manufactured as standard with radial internal clearance CN (normal) ➤ Table. CN is not stated in the designation.
Certain sizes are also available by agreement with the larger internal clearance C3.
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 self-aligning ball bearings with cylindrical bore
Nominal bore diameter |
Radial internal clearance |
||||
---|---|---|---|---|---|
d |
CN |
C3 |
|||
mm |
μm |
μm |
|||
over |
incl. |
min. |
max. |
min. |
max. |
– |
6 |
5 |
15 |
10 |
20 |
6 |
10 |
6 |
17 |
12 |
25 |
10 |
14 |
6 |
19 |
13 |
26 |
14 |
18 |
8 |
21 |
15 |
28 |
18 |
24 |
10 |
23 |
17 |
30 |
24 |
30 |
11 |
24 |
19 |
35 |
30 |
40 |
13 |
29 |
23 |
40 |
40 |
50 |
14 |
31 |
25 |
44 |
50 |
65 |
16 |
36 |
30 |
50 |
65 |
80 |
18 |
40 |
35 |
60 |
80 |
100 |
22 |
48 |
42 |
70 |
100 |
120 |
25 |
56 |
50 |
83 |
120 |
140 |
30 |
68 |
60 |
100 |
140 |
160 |
35 |
80 |
70 |
120 |
Radial internal clearance – bearings with tapered bore
The standard is C3
Self-aligning bearings with tapered bore are manufactured as standard with the larger radial internal clearance C3 ➤ Table.
Certain sizes are also available by agreement with internal clearance CN (normal).
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 self-aligning ball bearings with tapered bore
Nominal bore diameter |
Radial internal clearance |
||||
---|---|---|---|---|---|
d |
CN |
C3 |
|||
mm |
μm |
μm |
|||
over |
incl. |
min. |
max. |
min. |
max. |
18 |
24 |
13 |
26 |
20 |
33 |
24 |
30 |
15 |
28 |
23 |
39 |
30 |
40 |
19 |
35 |
29 |
46 |
40 |
50 |
22 |
39 |
33 |
52 |
50 |
65 |
27 |
47 |
41 |
61 |
65 |
80 |
35 |
57 |
50 |
75 |
80 |
100 |
42 |
68 |
62 |
90 |
100 |
120 |
50 |
81 |
75 |
108 |
120 |
140 |
60 |
98 |
90 |
130 |
140 |
160 |
65 |
110 |
100 |
150 |
Dimensions, tolerances
Dimension standards
The main dimensions of self-aligning ball bearings correspond to DIN 630:2011, with the exception of bearing series 112. Nominal dimensions of self-aligning ball bearings ➤ link.
Series 112
The dimensions of self-aligning ball bearings with extended inner ring (bearing series 112) correspond to DIN 630-2, which was withdrawn in 1993. Nominal dimensions of bearings ➤ link.
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 tolerances for the dimensional and running accuracy of self-aligning ball bearings correspond to tolerance class Normal in accordance with ISO 492:2014, except for the bearing bore of bearing series 112, which is manufactured to tolerance class J7. Tolerance values in accordance with ISO 492 ➤ link.
Suffixes
For a description of the suffixes used in this chapter see ➤ link and medias interchange http://www.schaeffler.de/std/1B69.
Suffixes and corresponding descriptions
Suffix |
Description of suffix |
|
---|---|---|
C3 |
Radial internal clearance C3 (larger than normal) |
Standard for bearings with tapered bore |
CN |
Radial internal clearance CN (normal) |
Special design for bearings with tapered bore, available by agreement |
K |
Tapered bore |
Standard |
M |
Solid brass cage |
Standard, cage material dependent on bearing series and bore code |
TVH |
Solid cage made from glass fibre reinforced polyamide PA66 |
Standard, cage material dependent on bearing series and bore code |
2RS |
Contact seal on both sides |
Dependent on bearing series |
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.
Self-aligning ball bearing with tapered bore: designation structure |
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Self-aligning ball bearing with tapered bore and adapter sleeve: designation structure |
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Dimensioning
Equivalent dynamic bearing load
P = Fr under purely radial load of constant magnitude and direction
The basic rating life equation L = (Cr/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 Fr. If this condition is met, the bearing load Fr is used in the rating life equation for P (P = Fr).
P is a substitute force for combined load and various load cases
If this condition is not met, 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.
Fa/Fr ≦ e or Fa/Fr > e
The calculation of P is dependent on the load ratio Fa/Fr and the calculation factor e ➤ 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, Y1, Y2 | - |
Factors ➤ link |
Equivalent static bearing load
For self-aligning ball bearings subjected to static load ➤ Equation.
Equivalent static bearing load
Legend
P0 | N |
Equivalent static bearing load |
F0r, F0a | N |
Largest radial or axial load present (maximum load) |
Y0 | - |
Axial load factor ➤ link |
Static load safety factor
In addition to the basic rating life L (L10h), 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 damage due to slippage, a minimum radial load of P > C0r/100 is required
In order that no slippage occurs between the contact partners, the self-aligning ball bearings must be constantly subjected to a sufficiently high load. Based on experience, a minimum radial load of the order of P > C0r/100 is thus 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 or tapered seating surface ➤ Figure to ➤ Figure. 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 – fit recommendations for bearings with cylindrical bore
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 ➤ link.
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
- shaft tolerances for adapter sleeves and withdrawal sleeves ➤ link
Axial location – fit recommendations for bearings with cylindrical bore
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.
Axial location – bearing series 112
Simple location by means of a grub screw
Bearings of series 112 are axially located by means of a grub screw, which engages in the slot in the bearing inner ring ➤ Figure. The grub screw also prevents the inner ring creeping on the shaft.
If a shaft is to be supported by two bearings, the slots in the inner ring must either be arranged on the sides of the bearing facing towards or away from each other ➤ Figure.
Axial location of bearing series 112 using grub screw and arrangement of self-aligning ball bearings, where a shaft is supported by two bearings
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Axial location – bearings with tapered bore
Location by means of locknut and tab washer
If a bearing with a tapered bore is mounted directly on a tapered journal the bearing can be axially located with ease using an axial locknut and tab washer ➤ Figure.
Self-aligning ball bearing
|
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Location of bearings by means of adapter sleeve
Mounting can be carried out quickly and reliably by means of wrench sets from Schaeffler
Self-aligning ball bearings with a tapered bore can be located easily and reliably on smooth or stepped cylindrical shafts by means of an adapter sleeve ➤ Figure. The adapter sleeve does not need to be secured on the shaft by any additional means. The bearings can be positioned at any point on smooth shafts. Axial load carrying capacity of bearing arrangements by means of adapter sleeve connection ➤ section.
Self-aligning ball bearing
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Location by means of adapter sleeve, axial support by means of a support ring
If very high axial forces are present, a support ring can also be used to provide axial support ➤ Figure. In this instance, the mounting dimensions of the support ring Ba and db in the product tables must be observed ➤ link.
Stepped shaft, axial support by means of a support ring
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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 self-aligning ball 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 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 |
Bearing seating surface |
Standard tolerance grades to ISO 286-1 |
||||
---|---|---|---|---|---|---|
to ISO 492 |
to DIN 620 |
Diameter tolerance |
Roundness tolerance |
Parallelism tolerance |
Total axial runout tolerance of abutment shoulders |
|
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 d (D) |
Recommended mean roughness value 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 |
Tolerances for tapered bearing seats
Specifications for tapered bearing seats
For bearings located directly on a tapered shaft journal, ➤ Figure, the data are in accordance with ➤ Figure.
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. However, they must also reliably prevent rotating parts of the bearing from grazing stationary parts. Proven mounting dimensions for the radii and diameters of the abutment shoulders ➤ link. These dimensions are limiting dimensions (maximum or minimum dimensions); the actual values should not be higher or lower than specified.
Suitable bearing housings for self-aligning ball bearings
A large range of housings is available
For economical, operationally reliable and easily interchangeable bearing arrangement units, the self-aligning ball bearings can also be combined with Schaeffler bearing housings ➤ Figure. These easy-to-fit units fulfil all of the requirements for modern machine and plant designs with favourable maintenance-related characteristics.
Due to the large number of application areas, an extensive range of bearing housings is available for bearings with cylindrical and tapered bores. These include split and unsplit plummer block housings, take-up housings, flanged housings and housings for specific industrial and railway applications. Detailed information on bearing housings can be found in publication GK 1 http://www.schaeffler.de/std/1B63. This book can be ordered from Schaeffler.
Split plummer block housing with a self-aligning ball bearing
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Mounting and dismounting
The mounting and dismounting options for self-aligning ball bearings, by thermal, hydraulic or mechanical methods, must be taken into consideration in the design of the bearing position.
Ensure that the bearings are not damaged during mounting
Self-aligning ball bearings are not separable. In the mounting of non‑separable bearings, the mounting forces must always be applied to the bearing ring with a tight fit.
Mounting of bearings with a tapered bore
Suitable methods
Bearings with a tapered bore are mounted with a tight fit on the shaft or adapter and withdrawal sleeve. The measurement of the reduction in radial internal clearance or of the axial drive-up distance of the inner ring on the tapered bearing seat serves as an indication of the tight fit.
Measuring the reduction in radial internal clearance
The measurement is usually carried out with a feeler gauge
The reduction in radial internal clearance is the difference between the radial internal clearance before mounting and the bearing clearance after mounting of the bearing ➤ Figure. The radial internal clearance must be measured first. During pressing on, the radial clearance (bearing clearance) must be checked until the necessary reduction in the radial internal clearance and the required tight fit is achieved.
Reduction in radial internal clearance sr = radial internal clearance before mounting sr1 = radial internal clearance after mounting sr – sr1 = reduction in radial internal clearance
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Measuring the axial drive-up distance
The axial drive-up distance can also be measured in place of the reduction in radial internal clearance ➤ Figure.
Axial drive-up distance sa = axial press-on distance (axial drive-up distance of the bearing) sr = radial internal clearance sr1 = radial internal clearance after pressing on sr – sr1 = reduction in radial internal clearance
|
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The malfunction-free operation of bearings presupposes that these have been mounted correctly. An insufficient operating clearance or inadequately tight fit on the shaft generally leads to bearing damage.
If there is any uncertainty regarding the practical application of both methods, Schaeffler must always be consulted.
The mounting of self-aligning ball bearings is also described in the Schaeffler publication BA 28. This BA publication can be requested from Schaeffler.
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: