Schaeffler Product catalogue - medias
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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.
 
   

Figure 1
Self-aligning ball bearing: speed comparison with barrel roller bearing, compensation of misalignments

nG =  limiting speed

 

imageref_18616707851_All.gif

 
 

Bearing design

 
 

Self-aligning ball bearings are available as:

 
   
 

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 2.

 

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 2.

 
imageref_17757201419_All.gif   Bearings with a tapered bore have a bore taper of 1:12 and the suffix K ➤ Table 5.  
 

   

Figure 2
Self-aligning ball bearings of basic design

Fr =  radial load
Fa =  axial load
Symbole/00016410_mei_in_0k_0k.gif  Self-aligning ball bearing with cylindrical bore, open
Symbole/00016411_mei_in_0k_0k.gif  Self-aligning ball bearing with tapered bore, open, bore taper 1:12

 

imageref_17772650635_All.gif

 
 

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 3. 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 8.

 
 

   

Figure 3
Self-aligning ball bearing with extended inner ring and locating slot

Fr =  radial load
Fa =  axial load
Symbole/00016410_mei_in_0k_0k.gif  Locating slot

 

imageref_19608137611_All.gif

 
 

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 on 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 4. 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 7.

 
 

   

Figure 4
Self-aligning ball bearings with adapter sleeve

Fr =  radial load
Fa =  axial load
Symbole/00016410_mei_in_0k_0k.gif  Self-aligning ball bearing, open
Symbole/00016411_mei_in_0k_0k.gif  Self-aligning ball bearing, lip seal on both sides
Symbole/00016412_mei_in_0k_0k.gif  Adapter sleeve
Symbole/00016413_mei_in_0k_0k.gif  Locknut
Symbole/00016414_mei_in_0k_0k.gif  Tab washer

 

imageref_17757447051_All.gif

 
 

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 5.

 
imageref_17757187211_All.gif   The projection is marked C1 in the product tables. This must be taken into consideration when defining the dimensions for the adjacent parts.  
 

   

Figure 5
Self-aligning ball bearing with ball projection

C1 =  ball projection

 

imageref_17772653451_All.gif

 
 

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 2 to ➤ Figure 4. Due to the point contact with which the rolling elements 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

imageref_17757187211_All.gif   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.  
imageref_18348417035_All.gif   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 from their central position

 

Under normal operating conditions and with a rotating inner ring, self‑aligning ball bearings can swivel up to 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.

 
imageref_18348417035_All.gif   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.

 
imageref_17757187211_All.gif   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 4. 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 ➤ Table 5.

 
 

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

 
 

The product tables give two speeds for most bearings ➤ dimension table:

 
 
  • the kinematic limiting speed nG
  • the thermal speed rating nϑr.
 
 

Limiting speeds

imageref_17757187211_All.gif   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 reference speeds 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

 
 

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 ➤ Table 1.

 
   
Table 1
Permissible temperature ranges
 

Operating temperature
Open self-aligning ball bearings
Sealed self-aligning
ball bearings
with brass cage
with polyamide cage PA66
imageref_19988082955_All.gif
   
–30 °C to +150 °C
–30 °C to +120 °C
–30 °C to +100 °C, limited by the lubricant and seal material

 
imageref_18348417035_All.gif   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 2. 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.

 
imageref_18348417035_All.gif   For high continuous temperatures and applications with difficult operating conditions, bearings with brass or sheet steel cages should be used. If there is any uncertainty regarding cage suitability, please consult Schaeffler.  
 

   
Table 2
Cage, cage suffix, bore code
 

Bearing series
Solid cage
made from polyamide PA66
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 3. CN is not stated in the designation.

 
imageref_18348417035_All.gif   Certain sizes are also available by agreement with the larger internal clearance C3.  
imageref_17757201419_All.gif   The values for radial internal clearance correspond to DIN 620-4:2004 (ISO 5753-1:2009) ➤ Table 3. They are valid for bearings which are free from load and measurement forces (without elastic deformation).  
 

   
Table 3
Radial internal clearance of self-aligning ball bearings with cylindrical bore
 

Nominal bore diameter
Radial internal clearance
d
CN
(Group N)
C3
(Group 3)
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 ball bearings with tapered bore are manufactured as stan­dard with the larger radial internal clearance C3 ➤ Table 4.

 
imageref_18348417035_All.gif   Certain sizes are also available by agreement with internal clearance CN (normal).  
imageref_17757201419_All.gif   The values for radial internal clearance correspond to DIN 620-4:2004 (ISO 5753-1:2009) ➤ Table 4. They are valid for bearings which are free from load and measurement forces (without elastic deformation).  
 

   
Table 4
Radial internal clearance of self-aligning ball bearings with tapered bore
 

Nominal bore diameter
Radial internal clearance
d
CN
(Group N)
C3
(Group 3)
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

imageref_17757201419_All.gif   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 ➤ dimension table.  

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 ➤ dimension table.

 
 

Chamfer dimensions

imageref_17757201419_All.gif   The limiting dimensions for chamfer dimensions correspond to DIN 620‑6:2004. Overview and limiting values   ➤ section. Nominal value of chamfer dimension ➤ dimension table.  
 

Tolerances

imageref_17757201419_All.gif   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 ➤ Table .  
 

Suffixes

 
 

For a description of the suffixes used in this chapter ➤ Table 5 and medias interchange http://www.schaeffler.de/std/1D52.

 
   
Table 5
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
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 6 and ➤ Figure 7. The composition of designations is subject to DIN 623-1    ➤ Figure.

 
 

   

Figure 6
Self-aligning ball bearing with tapered bore: designation structure


 

imageref_17772656011_en.gif

 
   

Figure 7
Self-aligning ball bearing with tapered bore and adapter sleeve: designation structure


 

imageref_17772736523_en.gif

 
 

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 1 and ➤ Equation 2.

 

Equation 1
Equivalent dynamic load
 
imageref_17794274443_All.gif


Equation 2
Equivalent dynamic load
 
imageref_17794276363_All.gif

Legend

 
P
 N
Equivalent dynamic bearing load
Fr
 N
Radial load
Fa
 N
Axial load
e, Y1, Y2
Factors ➤ dimension table.
 
 

Equivalent static bearing load

 

For self-aligning ball bearings subjected to static load ➤ Equation 3.

 

Equation 3
Equivalent static load
 
imageref_10903634315_All.gif

Legend

 
P0
 N
Equivalent static bearing load
F0r, F0a
 N
Largest radial or axial load present (maximum load)
Y0
Axial load factor ➤ dimension table.
 
 

Static load safety factor

S0 = C0/P0

 

In addition to the basic rating life L (L10h), it is also always necessary to check the static load safety factor S0 ➤ Equation 4.

 

Equation 4
Static load safety factor
 
imageref_27021597814984331_All.gif

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.

 
imageref_18348417035_All.gif   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 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 8 to ➤ Figure 11. 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 6 to ➤ Table 8.

 
 

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.

 
imageref_17757187211_All.gif   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 and ➤ Table .  
 

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

 
   
 

Axial location – location methods 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 fundamentally 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 8. The grub screw also prevents the inner ring creeping on the shaft.

 
imageref_17757187211_All.gif   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 bearings facing towards or away from each other ➤ Figure 8.  
 

   

Figure 8
Axial location of bearing series 112 using grub screw and arrangement of self-aligning ball bearings, where a shaft is supported by two bearings

Symbole/00016410_mei_in_0k_0k.gif  Grub screw

 

imageref_17772739851_All.gif

 
 

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 a locknut and tab washer ➤ Figure 9.

 
   

Figure 9
Self-aligning ball bearing with tapered bore, mounted directly on the tapered shaft journal

Symbole/00016410_mei_in_0k_0k.gif  Tapered journal with fixing thread
Symbole/00016411_mei_in_0k_0k.gif  Locknut
Symbole/00016412_mei_in_0k_0k.gif  Tab washer

 

imageref_17772742411_All.gif

 
 

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 with operational liability on smooth or stepped cylindrical shafts by means of an adapter sleeve ➤ Figure 10. 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 .

 
   

Figure 10
Self-aligning ball bearing with adapter sleeve located on smooth shaft

Symbole/00016410_mei_in_0k_0k.gif  Adapter sleeve
Symbole/00016411_mei_in_0k_0k.gif  Locknut
Symbole/00016412_mei_in_0k_0k.gif  Tab washer

 

imageref_19613651851_All.gif

 
 

Location by means of adapter sleeve, axial abutment by means of a support ring

 

If very high axial forces are present, a support ring can also be used to provide axial abutment ➤ Figure 11. In this instance, the mounting dimensions of the support ring Ba and db in the product tables must be observed ➤ dimension table.

 
   

Figure 11
Stepped shaft, axial abutment by means of a support ring

Symbole/00016410_mei_in_0k_0k.gif  Adapter sleeve
Symbole/00016411_mei_in_0k_0k.gif  Locknut
Symbole/00016412_mei_in_0k_0k.gif  Tab washer
Symbole/00016413_mei_in_0k_0k.gif  Support ring
Symbole/00016414_mei_in_0k_0k.gif  Shaft shoulder

 

imageref_17772744971_All.gif

 
 

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 6, tolerances t1 to t3 in accordance with   ➤ Figure. Numerical values for IT grades ➤ Table 7.

 
   
Table 6
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
Point load IT5/2
Point load IT5/2
Housing
IT7 (IT6)
Circumferential load IT5/2
Circumferential load IT5/2
IT5
Point load IT6/2
Point load IT6/2


 
   
Table 7
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 8.

 
 

   
Table 8
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

 
 

Tolerances for tapered bearing seats

Specifications for tapered bearing seats

 

For bearings located directly on a tapered shaft journal ➤ Figure 9, 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 ➤ dimension table. 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 12. These easy-to-fit units fulfil all of the requirements for modern machine and plant designs with favourable maintenance-related characteristics.

 
imageref_19614046091_en.gif   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/1D54. This book can be ordered from Schaeffler.  
   

Figure 12
Split plummer block housing with a self-aligning ball bearing

Symbole/00016410_mei_in_0k_0k.gif  Split plummer block housing SNV
Symbole/00016411_mei_in_0k_0k.gif  Self-aligning ball bearing

 

imageref_19608652299_All.gif

 
 

Mounting and dismounting

 
imageref_17757187211_All.gif   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 13. 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 thus the required tight fit is achieved.

 
 

   

Figure 13
Reduction in radial internal clearance

sr =  radial internal clearance before mounting
sr1 =  radial internal clearance after mounting
sr – sr1 =  reduction in radial internal clearance
Symbole/00016410_mei_in_0k_0k.gif  Before mounting
Symbole/00016411_mei_in_0k_0k.gif  After mounting

 

imageref_19987990795_All.gif

 
 

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 14.

 
   

Figure 14
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
Symbole/00016410_mei_in_0k_0k.gif  Before pressing on
Symbole/00016411_mei_in_0k_0k.gif  After pressing on

 

imageref_19987992715_All.gif

 
imageref_17757187211_All.gif   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.  
imageref_18348417035_All.gif   If there is any uncertainty regarding the practical application of both methods, Schaeffler must always be consulted.  
imageref_17757210635_All.gif   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.

 
imageref_21602891659_en.gif   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/1D53. 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.

 
imageref_18350433803_All.gif   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:

 
   
   
  
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