Table of contents
Needle roller bearingsNeedle roller bearings
Inner rings
Inner rings are used where:
- the shaft cannot be used as a rolling bearing raceway for needle roller and cage assemblies, drawn cup needle roller bearings with open ends, drawn cup needle roller bearings with closed end and needle roller bearings (it cannot be hardened and ground)
- needle roller bearings must be combined with wider inner rings in order to allow larger axial displacements of the shaft in relation to the housing (e. g. in bearings with a non-locating bearing function)
- optimum running surfaces are required for seal lips ➤ Figure and ➤ Figure
|
Wider inner ring, outside surface used as raceway for seal lip
|
 |
Product design
Design variants
The bearing components are available as:
Inner rings IR
The raceway is precision machined
Inner rings IR are made from hardened rolling bearing steel and have precision machined raceways ➤ Figure. Chamfers on the end faces facilitate the matching of the rings with the needle roller and cage assembly or of the bearing ring with the needle roller set and prevent damage to the seal lips of the bearings. Inner rings are available with and without a lubrication hole ➤ Figure. Rings with a lubrication hole have the suffix IS1 ➤ section, ➤ link.
Inner rings are also available by agreement with several lubrication holes.
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Inner rings IR
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X-life premium quality
Inner rings IR are supplied in the X-life design. The quality of the inner rings corresponds to the quality of X-life needle roller bearings. X-life inner rings include the suffix XL in the designation ➤ Figure.
X-life indicates a high product performance density and thus a particularly significant benefit to the customer.
Inner rings with the machining allowance “z” (special design)
z = a material allowance for finish grinding of the rings after fitting, where there are high demands on running accuracy
Inner rings are also available as a special design with a machining allowance “z” on the raceway. These inner rings have the suffix VGS ➤ section. The size of the machining allowance is dependent on the diameter of the inner ring raceway ➤ Table. The raceway is finish ground once the rings have been fitted, if high demands are placed on the running accuracy of the bearings.
Machining allowance
|
Raceway diameter F |
Machining allowance z |
Preground raceway diameter FVGS |
|
|---|---|---|---|
|
mm |
mm |
||
|
over |
incl. |
||
|
‒ |
50 |
0,1 |
FVGS = F + z |
|
50 |
80 |
0,15 |
|
|
80 |
180 |
0,2 |
|
|
180 |
250 |
0,25 |
|
|
250 |
315 |
0,3 |
|
|
315 |
400 |
0,35 |
|
|
400 |
500 |
0,4 |
|
Inner rings LR
The raceway is ground
Inner rings LR are produced from rolling bearing steel and are hardened ➤ Figure. The bore and running surface are ground. The end faces are not ground (turned) and the edges are broken. These rings have larger tolerances than the inner rings IR. As a result, they are particularly suitable for applications that allow larger width tolerances and less demanding requirements for axial runout. It is here that they give particularly economical bearing arrangements.
Catalogue HR 1 does not contain separate product tables for inner rings LR. Available inner rings LR are listed in the product tables for drawn cup needler roller bearings with open ends and with closed end ➤ link. For other available dimensions, please consult Schaeffler.
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Inner ring LR d = bore diameter F = raceway diameter B = width |
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Wider inner rings
Advantages of wider inner rings
The inner rings are available in several widths within the respective bore diameter ➤ link. Wider inner rings:
- permit larger axial displacements of the shaft in relation to the housing
- can be used as the running surface for the lips of contact seals, for example when using sealing rings G, GR and SD ➤ Figure
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Wider inner ring, also used as running surface for sealing rings
|
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Temperature range
Limiting values
The operating temperature of the inner rings is limited by the dimensional stability of the ring material ➤ Table.
Permissible temperature ranges
|
Operating temperature |
Inner rings |
|---|---|
|
|
–30 °C to +120 °C |
In the event of anticipated temperatures which lie outside the stated values, please contact Schaeffler.
Internal clearance
CN for the combination of needler roller bearing/inner ring
The radial internal clearance is dependent on the bearing design used in combination with the inner ring. When combined with Schaeffler needle roller bearings, inner rings have a radial internal clearance of CN ➤ Table.
C2 to C3 for the combination of drawn cup needle roller bearing with open ends or closed end/inner ring
When combined with Schaeffler drawn cup needle roller bearings with open ends or closed end, inner rings have an internal clearance of C2 to C3, depending on the raceway diameter ➤ Table.
The values for radial internal clearance correspond to DIN 620-4:2004 (ISO 5753-1:2009). These are valid for bearings which are free from load and measurement forces (without elastic deformation).
Radial internal clearance
|
Nominal |
Radial internal clearance |
||||||||
|---|---|---|---|---|---|---|---|---|---|
|
d |
C2 (Group 2) |
CN (Group N) |
C3 (Group 3) |
C4 (Group 4) |
|||||
|
mm |
μm |
μm |
μm |
μm |
|||||
|
over |
incl. |
min. |
max. |
min. |
max. |
min. |
max. |
min. |
max. |
|
‒ |
24 |
0 |
25 |
20 |
45 |
35 |
60 |
50 |
75 |
|
24 |
30 |
0 |
25 |
20 |
45 |
35 |
60 |
50 |
75 |
|
30 |
40 |
5 |
30 |
25 |
50 |
45 |
70 |
60 |
85 |
|
40 |
50 |
5 |
35 |
30 |
60 |
50 |
80 |
70 |
100 |
|
continued ▼ |
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Radial internal clearance
|
Nominal |
Radial internal clearance |
||||||||
|---|---|---|---|---|---|---|---|---|---|
|
d |
C2 (Group 2) |
CN (Group N) |
C3 (Group 3) |
C4 (Group 4) |
|||||
|
mm |
μm |
μm |
μm |
μm |
|||||
|
over |
incl. |
min. |
max. |
min. |
max. |
min. |
max. |
min. |
max. |
|
50 |
65 |
10 |
40 |
40 |
70 |
60 |
90 |
80 |
110 |
|
65 |
80 |
10 |
45 |
40 |
75 |
65 |
100 |
90 |
125 |
|
80 |
100 |
15 |
50 |
50 |
85 |
75 |
110 |
105 |
140 |
|
100 |
120 |
15 |
55 |
50 |
90 |
85 |
125 |
125 |
165 |
|
120 |
140 |
15 |
60 |
60 |
105 |
100 |
145 |
145 |
190 |
|
140 |
160 |
20 |
70 |
70 |
120 |
115 |
165 |
165 |
215 |
|
160 |
180 |
25 |
75 |
75 |
125 |
120 |
170 |
170 |
220 |
|
180 |
200 |
35 |
90 |
90 |
145 |
140 |
195 |
195 |
250 |
|
200 |
225 |
45 |
105 |
105 |
165 |
160 |
220 |
220 |
280 |
|
225 |
250 |
45 |
110 |
110 |
175 |
170 |
235 |
235 |
300 |
|
250 |
280 |
55 |
125 |
125 |
195 |
190 |
260 |
260 |
330 |
|
280 |
315 |
55 |
130 |
130 |
205 |
200 |
275 |
275 |
350 |
|
315 |
355 |
65 |
145 |
145 |
225 |
225 |
305 |
305 |
385 |
|
355 |
400 |
100 |
190 |
190 |
280 |
280 |
370 |
370 |
460 |
|
400 |
450 |
110 |
210 |
210 |
310 |
310 |
410 |
410 |
510 |
|
continued ▲ |
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Tolerances
The tolerances for the dimensional and running accuracy of inner rings IR correspond to tolerance class Normal in accordance with ISO 492:2014. Tolerance values in accordance with ISO 492 ➤ Table.
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 |
|
|---|---|---|
|
C2 |
Radial internal clearance C2 |
Standard or special design, depending on the rolling bearing used |
|
C3 |
Radial internal clearance C3 |
Standard or special design, depending on the rolling bearing used |
|
C4 |
Radial internal clearance C4 |
Standard or special design, depending on the rolling bearing used |
|
EGS |
Surface ground free from spiral marks for rotary shaft seals to DIN 3760 and DIN 3761 |
Special design, available by agreement |
|
IS1 |
With lubrication hole |
Standard for IR inner rings within certain limits |
|
VGS |
Machining allowance z on raceway ➤ Table |
Special design, available by agreement |
Structure of bearing designation
The designation of inner rings follows a set model. Examples ➤ Figure and ➤ Figure.
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Inner ring LR: designation structure |
 |
|
Inner ring IR with lubrication hole: designation structure |
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Design of bearing arrangements
Axial location of inner rings
Always locate inner rings axially on both sides
The bearing rings must not be allowed to undergo lateral creep. In order to reliably prevent axial displacements of the inner rings on the shaft where a tight or loose fit is present, these must be located axially on both sides. On one side, the rings can be abutted against a shaft shoulder and, for location on the opposing side, retaining rings, spacer rings or shaft nuts are suitable ➤ Figure.
Design of adjacent parts
The abutment shoulders for the rings should be sufficiently high and perpendicular to the bearing axis. The transition from the bearing seat to the abutment shoulder must be designed with rounding to DIN 5418 or an undercut to DIN 509. In this instance, the minimum values for the chamfer dimensions in the product tables must be observed ➤ link. The overlap between the retaining rings and the end faces of the bearing rings must be sufficiently large ➤ Figure.
The maximum chamfer dimensions for the inner rings in accordance with DIN 620-6 must be taken into consideration.
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Inner ring axially located on both sides
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Mounting and dismounting
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.
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The further development of products may also result in technical changes to catalogue products
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