Schaeffler Product catalogue - medias
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Combined bearings
 

The bearings:

 
 
  • can support high radial loads and moderate axial loads by means of a single bearing position ➤ Figure 1
  • are suitable for applications with a very small radial design envelope, where the raceway on the shaft is designed as a rolling bearing
    Ready-to-fit machine element, often defined in standards, for transmitting movements, loads and tilting moments with a high level of efficiency; rolling bearings consist of rolling elements, cages and raceways on rings, guideways or carriages as well as lubricant and, if necessary, seals and accessories
    raceway (direct bearing arrangement)
  • permit relatively high speeds, if the rolling element
    Point or rotationally symmetrical bodies for transmitting loads between raceways.
    set in the axial bearing component is not full complement
    Design of rolling bearing with the largest possible number of rolling elements (balls or rollers) by the omission of cages or cage elements
    but guided by a cage
  • have a high running accuracy
  • permit locating bearing
    Bearing capable of transmitting axial loads from both directions and radial loads
    arrangements with only a very small radial design envelope
  • result in axially rigid bearing arrangements
  • are easy to mount as they are not self-retaining in many cases
  • permit technically straightforward, economical and cost-effective designs.
 
   

Figure 1
Combined needle roller bearing
See Rolling bearing
/ needle roller
See Rolling element
bearing: comparison of load
Load which, for example, is to be supported at a friction point. Also strain from pressure and/or heat.

See Contact surface
direction

Fr =  radial load
Fa =  axial load
Symbole/00016410_mei_in_0k_0k.gif  Needle roller/axial deep groove ball bearing NKX
Symbole/00016411_mei_in_0k_0k.gif  Needle roller bearing NK

 

imageref_22438038539_All.gif

 
 

Bearing design

 
 

The standard product range of combined needle roller
See Rolling element
bearings comprises:

 
   
 

The majority of these needle roller
See Rolling element
bearings are X-life bearings ➤ link .

 
 

Combined needle roller
See Rolling element
bearings

The bearings comprise a radial component and an axial component

 

Combined needle roller
See Rolling element
bearings comprise a radial needle roller
See Rolling element
bearing, which is combined with an axial bearing component ➤ Figure 3, ➤ Figure 5 and ➤ Figure 6. These bearings can support radial as well as axial loads with just one bearing and permit locating bearing
Bearing capable of transmitting axial loads from both directions and radial loads
arrangements with only a small radial design envelope ➤ Figure 2 and ➤ section . They are suitable, for example, where radial and axial loads are present and simple axial contact washers are no longer able to support the axial loads on account of their size, high speeds or inadequate lubrication, and other locating bearings require too much installation space.

 
   

Figure 2
Combined needle roller
See Rolling element
bearings, radial and axial dynamic load
The term dynamic indicates that the operating condition is with the bearing rotating. This is not a variable load.
carrying capacity

Cr =  radial basic dynamic load
The term dynamic indicates that the operating condition is with the bearing rotating. This is not a variable load.
rating
Ca =  basic axial dynamic load
The term dynamic indicates that the operating condition is with the bearing rotating. This is not a variable load.
rating

 

imageref_22438043019_All.gif

 
 

Needle roller/axial deep groove ball bearings

Suitable for compact direct bearing arrangements on the shaft

 

Needle roller/axial deep groove ball bearings do not have an inner ring and are therefore particularly compact in a radial direction ➤ Figure 3. However, they require a shaft raceway that is hardened and ground ➤ section . If the shaft cannot be used as a rolling bearing
Ready-to-fit machine element, often defined in standards, for transmitting movements, loads and tilting moments with a high level of efficiency; rolling bearings consist of rolling elements, cages and raceways on rings, guideways or carriages as well as lubricant and, if necessary, seals and accessories
raceway, inner rings IR can be used instead ➤ Figure 4. The suitable inner rings are given in the product tables and must be ordered in addition to the bearing ➤ dimension table. For lubrication, the outer ring of the radial bearing component has a lubrication
Feed of fresh lubricant to friction points. Fresh lubricant mixes with used lubricant at the friction point. Lubricant feed is by means of lubrication equipment. The time period for relubrication is shorter than that for the lubricant change interval.

See
Lubrication method
Lubrication condition
Recirculating lubrication
Lubrication technology
One-off lubrication
Hydrodynamic lubrication
Lubricant change intervall
Lubricant change
Lubricant
Lubricant paste
Oil
Grease
Lubrication film
Lubrication system
groove and lubrication
Feed of fresh lubricant to friction points. Fresh lubricant mixes with used lubricant at the friction point. Lubricant feed is by means of lubrication equipment. The time period for relubrication is shorter than that for the lubricant change interval.

See
Lubrication method
Lubrication condition
Recirculating lubrication
Lubrication technology
One-off lubrication
Hydrodynamic lubrication
Lubricant change intervall
Lubricant change
Lubricant
Lubricant paste
Oil
Grease
Lubrication film
Lubrication system
holes.

 
 

Type NX, NX..-Z

The rolling element
Point or rotationally symmetrical bodies for transmitting loads between raceways.
set for the axial bearing component is a full complement
Design of rolling bearing with the largest possible number of rolling elements (balls or rollers) by the omission of cages or cage elements
ball system

 

Needle roller/axial deep groove ball bearings NX and NX..-Z have a full complement
Design of rolling bearing with the largest possible number of rolling elements (balls or rollers) by the omission of cages or cage elements
ball rolling element
Point or rotationally symmetrical bodies for transmitting loads between raceways.
set and an extremely low radial section height ➤ Figure 3. Due to the compact radial dimensions, bearing arrangements can be achieved with very small shaft centre distances, such as those that may be present in multi-spindle drilling machines. A sheet steel end cap secured to the radial bearing component grips the shaft locating washing of the axial bearing and holds the axial bearing component together ➤ Figure 3. As a result, the bearings are self‑retaining. The sheet metal caps for bearings NX have lubrication
Feed of fresh lubricant to friction points. Fresh lubricant mixes with used lubricant at the friction point. Lubricant feed is by means of lubrication equipment. The time period for relubrication is shorter than that for the lubricant change interval.

See
Lubrication method
Lubrication condition
Recirculating lubrication
Lubrication technology
One-off lubrication
Hydrodynamic lubrication
Lubricant change intervall
Lubricant change
Lubricant
Lubricant paste
Oil
Grease
Lubrication film
Lubrication system
holes for oil
Fluid lubricant with a mineral oil and/or synthetic oil base, usually with active ingredients or additives.
lubrication ➤ Figure 3 and ➤ section .

 
   

Figure 3
Needle roller/axial deep groove ball bearing NX without inner ring

Fr =  radial load
Fa =  axial load
Symbole/00016410_mei_in_0k_0k.gif  NX, full complement
Design of rolling bearing with the largest possible number of rolling elements (balls or rollers) by the omission of cages or cage elements
axial ball bearing component, with end cap, lubrication
Feed of fresh lubricant to friction points. Fresh lubricant mixes with used lubricant at the friction point. Lubricant feed is by means of lubrication equipment. The time period for relubrication is shorter than that for the lubricant change interval.

See
Lubrication method
Lubrication condition
Recirculating lubrication
Lubrication technology
One-off lubrication
Hydrodynamic lubrication
Lubricant change intervall
Lubricant change
Lubricant
Lubricant paste
Oil
Grease
Lubrication film
Lubrication system
holes in the cap
Symbole/00016411_mei_in_0k_0k.gif  NX..-Z, full complement
Design of rolling bearing with the largest possible number of rolling elements (balls or rollers) by the omission of cages or cage elements
axial ball bearing component, with end cap, no lubrication
Feed of fresh lubricant to friction points. Fresh lubricant mixes with used lubricant at the friction point. Lubricant feed is by means of lubrication equipment. The time period for relubrication is shorter than that for the lubricant change interval.

See
Lubrication method
Lubrication condition
Recirculating lubrication
Lubrication technology
One-off lubrication
Hydrodynamic lubrication
Lubricant change intervall
Lubricant change
Lubricant
Lubricant paste
Oil
Grease
Lubrication film
Lubrication system
holes in the cap
Symbole/00016412_mei_in_0k_0k.gif  End cap

 

imageref_22438046347_All.gif

 
   

Figure 4
Needle roller/axial deep groove ball bearing NX..-Z with inner ring

Symbole/00016410_mei_in_0k_0k.gif  Inner ring IR

 

imageref_22438062475_All.gif

 
 

Type NKX, NKX..-Z

The rolling element
Point or rotationally symmetrical bodies for transmitting loads between raceways.
set for the axial bearing component is guided by a cage

 

In bearings NKX and NKX..-Z, the rolling element
Point or rotationally symmetrical bodies for transmitting loads between raceways.
set is not a full comp­lement ball system, as is present in bearings NX, but is retained by a cage ➤ Figure 5. The ball and cage
The part of a rolling bearing which separates, retains and, where necessary, guides the rolling elements
assembly corresponds to an axial deep groove ball bearing of series 511. As a result of the cage, these bearings are suitable for higher speeds than bearings of the full complement
Design of rolling bearing with the largest possible number of rolling elements (balls or rollers) by the omission of cages or cage elements
design ➤ dimension table.

 

Type NKX

 

Bearings NKX are not self-retaining, i.e radial needle roller
See Rolling element
bearing, axial ball and cage
The part of a rolling bearing which separates, retains and, where necessary, guides the rolling elements
assembly and shaft locating washer can be fitted independently of each other ➤ Figure 5.

 

Type NKX..-Z

 

Type NKX..-Z has a sheet steel end cap, which holds the axial bearing component together, i.e. the bearings are self-retaining. The cap is designed without lubrication
Feed of fresh lubricant to friction points. Fresh lubricant mixes with used lubricant at the friction point. Lubricant feed is by means of lubrication equipment. The time period for relubrication is shorter than that for the lubricant change interval.

See
Lubrication method
Lubrication condition
Recirculating lubrication
Lubrication technology
One-off lubrication
Hydrodynamic lubrication
Lubricant change intervall
Lubricant change
Lubricant
Lubricant paste
Oil
Grease
Lubrication film
Lubrication system
holes and is rigidly connected to the housing
See Mounting dimenstions
locating washer of the radial bearing component ➤ Figure 5.

 
 

   

Figure 5
Needle roller/axial deep groove ball bearings without inner ring

Fr =  radial load
Fa =  axial load
Symbole/00016410_mei_in_0k_0k.gif  NKX, axial bearing component with ball and cage
The part of a rolling bearing which separates, retains and, where necessary, guides the rolling elements
assembly, without end cap
Symbole/00016411_mei_in_0k_0k.gif  NKX..-Z, axial bearing component with ball and cage
The part of a rolling bearing which separates, retains and, where necessary, guides the rolling elements
assembly, with end cap, no lubrication
Feed of fresh lubricant to friction points. Fresh lubricant mixes with used lubricant at the friction point. Lubricant feed is by means of lubrication equipment. The time period for relubrication is shorter than that for the lubricant change interval.

See
Lubrication method
Lubrication condition
Recirculating lubrication
Lubrication technology
One-off lubrication
Hydrodynamic lubrication
Lubricant change intervall
Lubricant change
Lubricant
Lubricant paste
Oil
Grease
Lubrication film
Lubrication system
holes in the cap
Symbole/00016412_mei_in_0k_0k.gif  End cap

 

imageref_22438065547_All.gif

 
 

Needle roller/axial cylindrical roller bearings

 

Type NKXR, NKXR..-Z

The rolling element
Point or rotationally symmetrical bodies for transmitting loads between raceways.
set for the axial bearing component is guided by a cage

 

These bearings comprise a radial needle roller bearing
See Rolling bearing
and an axial cylindrical roller bearing
See Rolling bearing
of series 811 with a plastic cage. They do not have an inner ring and require a shaft raceway that is hardened and ground ➤ Figure 6 and ➤ section . If the shaft cannot be used as a rolling bearing
Ready-to-fit machine element, often defined in standards, for transmitting movements, loads and tilting moments with a high level of efficiency; rolling bearings consist of rolling elements, cages and raceways on rings, guideways or carriages as well as lubricant and, if necessary, seals and accessories
raceway, inner rings IR can be used instead ➤ Figure 7. The suitable inner rings are given in the product tables and must be ordered in addition to the bearing ➤ dimension table. For lubrication, the outer ring of the radial bearing component has a lubrication
Feed of fresh lubricant to friction points. Fresh lubricant mixes with used lubricant at the friction point. Lubricant feed is by means of lubrication equipment. The time period for relubrication is shorter than that for the lubricant change interval.

See
Lubrication method
Lubrication condition
Recirculating lubrication
Lubrication technology
One-off lubrication
Hydrodynamic lubrication
Lubricant change intervall
Lubricant change
Lubricant
Lubricant paste
Oil
Grease
Lubrication film
Lubrication system
groove and lubrication
Feed of fresh lubricant to friction points. Fresh lubricant mixes with used lubricant at the friction point. Lubricant feed is by means of lubrication equipment. The time period for relubrication is shorter than that for the lubricant change interval.

See
Lubrication method
Lubrication condition
Recirculating lubrication
Lubrication technology
One-off lubrication
Hydrodynamic lubrication
Lubricant change intervall
Lubricant change
Lubricant
Lubricant paste
Oil
Grease
Lubrication film
Lubrication system
holes.

 

Type NKXR

 

Type NKXR is not self-retaining, i.e. the radial needle roller
See Rolling element
bearing, axial cylindrical roller bearing
See Rolling bearing
and shaft locating washer can be fitted independently of each other ➤ Figure 6.

 

Type NKXR..-Z

 

A sheet steel end cap secured to the radial bearing component grips the shaft locating washing of the axial cylindrical roller bearing
See Rolling bearing
and holds the axial bearing component together. As a result, these bearings are self‑retaining ➤ Figure 6.

 
 

   

Figure 6
Needle roller/axial cylindrical roller bearings without inner ring

Fr =  radial load
Fa =  axial load
Symbole/00016410_mei_in_0k_0k.gif  NKXR, axial bearing component with roller and cage
The part of a rolling bearing which separates, retains and, where necessary, guides the rolling elements
assembly, without end cap
Symbole/00016411_mei_in_0k_0k.gif  NKXR..-Z, axial bearing component with roller and cage
The part of a rolling bearing which separates, retains and, where necessary, guides the rolling elements
assembly, with end cap, no lubrication
Feed of fresh lubricant to friction points. Fresh lubricant mixes with used lubricant at the friction point. Lubricant feed is by means of lubrication equipment. The time period for relubrication is shorter than that for the lubricant change interval.

See
Lubrication method
Lubrication condition
Recirculating lubrication
Lubrication technology
One-off lubrication
Hydrodynamic lubrication
Lubricant change intervall
Lubricant change
Lubricant
Lubricant paste
Oil
Grease
Lubrication film
Lubrication system
holes in the cap
Symbole/00016412_mei_in_0k_0k.gif  End cap

 

imageref_22438068619_All.gif

 
   

Figure 7
Needle roller/axial cylindrical roller bearing NKXR with inner ring

Symbole/00016410_mei_in_0k_0k.gif  Inner ring IR

 

imageref_22438071691_All.gif

 
 

Needle roller/angular contact ball bearings

 

Type NKIA, NKIB

The rolling element
Point or rotationally symmetrical bodies for transmitting loads between raceways.
set for the axial bearing component is guided by a cage

 

Needle roller/angular contact ball bearings comprise a radial needle roller
See Rolling element
bearing, an angular contact ball bearing as the axial component and an inner ring ➤ Figure 8and ➤ Figure 9. In the case of type NKIA the inner ring is of a single-piece design, whereas design NKIB has one narrow and one wide inner ring. The ball cage
The part of a rolling bearing which separates, retains and, where necessary, guides the rolling elements
of the axial bearing com­ponent is made from plastic ➤ Figure 8 and ➤ Figure 9 and ➤ section . The bearings have a low radial section height and are suitable for high speeds ➤ dimension table. As needle roller/angular contact ball bearings are not self-retaining, the inner ring can be mounted independently of the outer ring and needle roller
See Rolling element
and ball set. During fitting it must, however, be ensured that the bearing rings are not interchanged with rings from other bearings, but are always mounted in the delivered matched pair.

 
   

Figure 8
Needle roller/angular contact ball bearing NKIA

Fr =  radial load
Fa =  axial load

 

imageref_22438087563_All.gif

 
   

Figure 9
Needle roller/angular contact ball bearing NKIB

Fr =  radial load
Fa =  axial load
Symbole/00016410_mei_in_0k_0k.gif  Wide inner ring
Symbole/00016411_mei_in_0k_0k.gif  Narrow inner ring

 

imageref_22438092939_All.gif

 
 

X-life premium quality

imageref_19964530187_All.gif   The combined needle roller
See Rolling element
bearings described here are X-life bearings. They are characterised by a very high load
Load which, for example, is to be supported at a friction point. Also strain from pressure and/or heat.

See Contact surface
carrying capacity and long rating life. This is achieved, for example, through the modified internal construction and optimised contact geometry between the rolling elements and raceways, as well as through the higher quality
See DIN 55 350 part 11 and ISO 8402 for terminology and definitions.
of the steel and rolling elements, higher surface quality
See DIN 55 350 part 11 and ISO 8402 for terminology and definitions.
and appropriate heat treatment.
 
 

Advantages

 

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

 
 
  • a more favourable load
    Load which, for example, is to be supported at a friction point. Also strain from pressure and/or heat.

    See Contact surface
    distribution in the bearing and thus a higher dynamic load
    The term dynamic indicates that the operating condition is with the bearing rotating. This is not a variable load.
    carrying capacity of the bearings
  • quieter running
  • running with reduced friction
    The resistance to relative movement of two bodies in contact with each other; subdivided into friction terms, friction types and friction conditions
    and greater energy efficiency
  • lower heat generation in the bearing
  • higher possible speeds
  • lower lubricant
    Gaseous, fluid, consistent, plastic or solid material for reduction of friction and wear between two friction elements.
    consumption and, consequently, longer maintenance
    Inspection, maintenance and repair of equipment and machines.
    intervals
  • a measurably longer operating life
    See Life, rating
    of the bearings
  • high operational security
  • compact, environmentally-friendly bearing arrangements.
 

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

 

Combined needle roller
See Rolling element
bearings in X-life quality
See DIN 55 350 part 11 and ISO 8402 for terminology and definitions.
include the suffix XL in the designation ➤ Figure 13 to ➤ Figure 15 and ➤ dimension table.

 
imageref_17757210635_All.gif   X-life indicates a high product performance density
Mass ratio of a lubricant with respect to its volume to DIN 51 757.

Usual units for solid materials (apparent density):
- gramms per cubic centimeter g/cm3

fluids:
- gramms per millilitre g/ml

gases:
- kilogrammes per cubic meter kg/cm3

Other permissible units are kg/dm3, kg/cm3, kg/l
and thus a particularly significant benefit to the customer.
 
 

Load carrying capacity

 
 

Needle roller/axial deep groove ball bearings NX, NX..-Z, NKX, NKX..-Z

Suitable for moderate axial loads

 

Needle roller/axial deep groove ball bearings support high radial loads and moderate axial loads in one direction ➤ Figure 3 to ➤ Figure 5. Bearings with a full complement
Design of rolling bearing with the largest possible number of rolling elements (balls or rollers) by the omission of cages or cage elements
ball set have a higher axial load
Force acting in the direction of the shaft.
carrying capacity than bearings with a cage-guided axial component ➤ Figure 2.

 
 

Bearing arrangement for supporting axial loads in both directions

Mounting of two needle roller/axial deep groove ball bearings in a mirror image arrangement

 

Needle roller/axial deep groove ball bearings can support axial loads in one direction only. If no temperature-induced changes in length occur during operation in an arrangement of short shafts, two bearings can also be used to support axial loads in both directions, which are then mounted in a mirror image arrangement ➤ Figure 10. The bearing parts should, however, be elastically preloaded in an axial direction, for example by means of disc springs ➤ Figure 10. The elastic preload
Force due to negative operating clearance or negative bearing clearance in rolling bearings
ensures that the unloaded axial bearing component runs without slippage ➤ section . The preload
Force due to negative operating clearance or negative bearing clearance in rolling bearings
also improves the operating behaviour of axial ball bearings and reduces running noise.

 
   

Figure 10
Two needle roller/axial deep groove ball bearings NKX mounted in a mirror image arrangement and axially preloaded with disc springs

Symbole/00016410_mei_in_0k_0k.gif  Needle roller/axial deep groove ball bearing NKX
Symbole/00016411_mei_in_0k_0k.gif  Disc spring set
Symbole/00016412_mei_in_0k_0k.gif  Shaft nut for preloading

 

imageref_22438096011_All.gif

 
 

Needle roller/axial cylindrical roller bearings NKXR, NKXR..-Z

Suitable for high axial loads

 

Needle roller/axial cylindrical roller bearings support high radial loads and also, due to the line contact of the cylindrical rollers, high axial loads in one direction ➤ Figure 2, ➤ Figure 8 and ➤ Figure 9.

 
 

Bearing arrangement for supporting axial loads in both directions

Mounting of two needle roller/axial cylindrical roller bearings in a mirror image arrangement

 

Needle roller/axial cylindrical roller bearings can support axial loads in one direction only. If no temperature-induced changes in length occur during operation in an arrangement of short shafts, two bearings can also be used to support axial loads in both directions, which are then mounted in a mirror image arrangement. The bearing parts should, however, be elastically preloaded in an axial direction, for example by means of disc springs ➤ Figure 10. The elastic preload
Force due to negative operating clearance or negative bearing clearance in rolling bearings
ensures that the unloaded axial bearing component runs without slippage. The preload
Force due to negative operating clearance or negative bearing clearance in rolling bearings
also improves the operating behaviour of needle roller/axial cylindrical roller bearings and reduces running noise.

 
 

Needle roller/angular contact ball bearings NKIA, NKIB

NKIA for axial forces in one direction, NKIB for alternating axial forces

 

The radial bearing supports high radial loads, the angular contact ball bearing supports smaller axial forces. NKIA can support axial loads from one direction only ➤ Figure 8. NKIB has one narrow and one wide inner ring ➤ Figure 9. At the point where the inner rings join, there is a shoulder on both sides for guidance of the ball and cage
The part of a rolling bearing which separates, retains and, where necessary, guides the rolling elements
assembly. As a result, these bearings are also suitable for supporting axial forces alternating in direction, i.e. as locating bearings, they can guide the shaft axially in both directions. The shaft is guided axially with an axial clearance
The amount by which the bearing rings in a fitted bearing can be moved in an axial direction from one end position to the other without axial loading.
of 0,08 mm to 0,25 mm.

 
 

Replacement of inner rings

 

In standard bearings of series NKIA and NKIB, the inner rings are matched to the enveloping circle tolerance F6 and can be interchanged with each other (mixed use) within the same accuracy
Deviation of the actual dimension from the nominal dimension as described by tolerances. For monorail systems, the parallel deviation of the reference surfaces within given tolerances.

See
Running accuracy
Dimensional accuracy
class.

 
imageref_17757187211_All.gif   When mounting bearings NKIB, both inner ring parts must be located axially clearance-free against each other. The narrow inner ring has a larger bore diameter. This results in an interference fit if a shaft tolerance k6 is used.  
 

Bearing arrangement for supporting axial loads in both directions with bearings NKIA

Mounting of two needle roller/angular contact ball bearings in a mirror image arrangement

 

Needle roller/angular contact ball bearings NKIA support axial loads in one direction. In order to support axial loads in both directions, two bearings NKIA can also be used, which are then mounted in a mirror image arrangement ➤ Figure 11.

 
   

Figure 11
Two needle roller/angular contact ball bearings NKIA mounted in a mirror image arrangement

Symbole/00016410_mei_in_0k_0k.gif  Needle roller/angular contact ball bearing NKIA
Symbole/00016411_mei_in_0k_0k.gif  Shaft nut for preloading

 

imageref_22438099083_All.gif

 
 

Support of axial forces

Preloading of the axial bearing component

 

The axial bearing component must be preloaded to 1% of the axial basic static load
Load which, for example, is to be supported at a friction point. Also strain from pressure and/or heat.

See Contact surface
rating C0a (for example using disc springs). The basic load
Load which, for example, is to be supported at a friction point. Also strain from pressure and/or heat.

See Contact surface
ratings C0a are stated in the product tables.

 
 

Needle roller/axial deep groove ball bearings and needle roller/ axial cylindrical roller bearings

Shortening of the retaining rings where there is little distance between the shafts

 

In order to support axial forces, the bearings must be abutted by means of snap rings on the outer ring or a housing
See Mounting dimenstions
shoulder. If there is little distance between the shaft centres, the snap rings should be shortened ➤ Figure 12. Snap rings WR and SW are available from trade outlets. If the bearings are to support axial forces from alternating directions, two bearings must be fitted opposed to each other. The unloaded bearing must then be axially preloaded, for example by means of disc springs ➤ Figure 10. This allows compensation of thermal expansion.

 
   

Figure 12
Bearing arrangement with shortened snap rings

Symbole/00016410_mei_in_0k_0k.gif  Snap ring
Symbole/00016411_mei_in_0k_0k.gif  Shortened area

 

imageref_22442646539_All.gif

 
 

Shaft raceway designed in accordance with DIN 617

imageref_17757187211_All.gif   If the surface of the shaft raceway is produced to DIN 617, the basic load
Load which, for example, is to be supported at a friction point. Also strain from pressure and/or heat.

See Contact surface
ratings Cr in the product tables must be reduced by 15%.
 
 

Compensation of angular misalignments

 

The bearings are not suitable for the compensation of shaft misalignments relative to the housing

 

Combined needle roller
See Rolling element
bearings are not suitable for the compensation of angular misalignments. The extent to which a misalignment
Deviation of an actual line from a theoretical ideal line, for example a bearing axis from the shaft axis; may be due to machining, flexing of shaft or deformation of housing.
of the shaft can be tolerated relative to the housing
See Mounting dimenstions
bore is dependent on factors such as the design of the bearing arrangement, the size of the bearing, the operating clearance
The amount by which the bearing rings in a fitted bearing can be moved in the radial or axial direction from one extreme position to the other.
and the load
Load which, for example, is to be supported at a friction point. Also strain from pressure and/or heat.

See Contact surface
etc. As a result, no guide value can be specified here for a possible misalignment. If angular misalignments occur, aligning needle roller
See Rolling element
bearings can, for example, be used in combination with an axial bearing, depending on the application.

 
imageref_17757187211_All.gif   In all cases, misalignments cause increased running noise, place increased strain on the cages and have a harmful influence on the operating life
See Life, rating
of the bearings.
 
 

Lubrication

 

Greasing of the radial bearing component prior to initial operation

 

In bearings with grease
See
Lubricant
Grease cartridge
Fatty acids
lubrication, the radial bearing component should be greased before initial operation using a grease
See
Lubricant
Grease cartridge
Fatty acids
of similar quality
See DIN 55 350 part 11 and ISO 8402 for terminology and definitions.
to that used in the axial bearing component.

 

Determining the relubrication interval

 

In order to determine the relubrication interval, values must be calculated separately for the axial and radial bearing components and the lower values should be used.

 

Compatibility with plastic cages

 

When using bearings with plastic cages, compatibility between the lubricant
Gaseous, fluid, consistent, plastic or solid material for reduction of friction and wear between two friction elements.
and the cage
The part of a rolling bearing which separates, retains and, where necessary, guides the rolling elements
material must be ensured if synthetic oils, lubricating greases
Consistent grease with a mineral oil and/or synthetic oil base with thickener as well as active ingredients or additives. See DIN 51 825 part 1 for demands on greases, grease type K, operating temperature range -20 to 140°C or DIN 51 825 part 2, for grease type KT.
with a synthetic oil
Fluid lubricant with a mineral oil and/or synthetic oil base, usually with active ingredients or additives.
base or lubricants containing a high proportion of EP additives are used.

 
 

Needle roller/axial deep groove ball bearings

 

Type NX, NKX

NX, NKX for oil
Fluid lubricant with a mineral oil and/or synthetic oil base, usually with active ingredients or additives.
lubrication, NX..-Z, NKX..-Z for grease
See
Lubricant
Grease cartridge
Fatty acids
lubrication

 

NX and NKX are intended for oil
Fluid lubricant with a mineral oil and/or synthetic oil base, usually with active ingredients or additives.
lubrication, therefore the bearings are not greased. Oil
Fluid lubricant with a mineral oil and/or synthetic oil base, usually with active ingredients or additives.
lubrication
Feed of fresh lubricant to friction points. Fresh lubricant mixes with used lubricant at the friction point. Lubricant feed is by means of lubrication equipment. The time period for relubrication is shorter than that for the lubricant change interval.

See
Lubrication method
Lubrication condition
Recirculating lubrication
Lubrication technology
One-off lubrication
Hydrodynamic lubrication
Lubricant change intervall
Lubricant change
Lubricant
Lubricant paste
Oil
Grease
Lubrication film
Lubrication system
is carried out via the lubrication
Feed of fresh lubricant to friction points. Fresh lubricant mixes with used lubricant at the friction point. Lubricant feed is by means of lubrication equipment. The time period for relubrication is shorter than that for the lubricant change interval.

See
Lubrication method
Lubrication condition
Recirculating lubrication
Lubrication technology
One-off lubrication
Hydrodynamic lubrication
Lubricant change intervall
Lubricant change
Lubricant
Lubricant paste
Oil
Grease
Lubrication film
Lubrication system
holes in the end cap ➤ Figure 5. If grease
See
Lubricant
Grease cartridge
Fatty acids
lubrication
Feed of fresh lubricant to friction points. Fresh lubricant mixes with used lubricant at the friction point. Lubricant feed is by means of lubrication equipment. The time period for relubrication is shorter than that for the lubricant change interval.

See
Lubrication method
Lubrication condition
Recirculating lubrication
Lubrication technology
One-off lubrication
Hydrodynamic lubrication
Lubricant change intervall
Lubricant change
Lubricant
Lubricant paste
Oil
Grease
Lubrication film
Lubrication system
is intended, bearings of type NX..-Z or NXK..-Z should be used. In the case of these bearings, the axial bearing component is greased using a lithium complex soap grease
See
Lubricant
Grease cartridge
Fatty acids
to GA08. The end caps do not have lubrication
Feed of fresh lubricant to friction points. Fresh lubricant mixes with used lubricant at the friction point. Lubricant feed is by means of lubrication equipment. The time period for relubrication is shorter than that for the lubricant change interval.

See
Lubrication method
Lubrication condition
Recirculating lubrication
Lubrication technology
One-off lubrication
Hydrodynamic lubrication
Lubricant change intervall
Lubricant change
Lubricant
Lubricant paste
Oil
Grease
Lubrication film
Lubrication system
holes.

 
 

Type NKX, NKX..-Z

Type NKX

 

Type NKX does not have a cap which holds the axial bearing component together ➤ Figure 5. As a result, these bearings are not self-retaining. They should be used with oil
Fluid lubricant with a mineral oil and/or synthetic oil base, usually with active ingredients or additives.
lubrication
Feed of fresh lubricant to friction points. Fresh lubricant mixes with used lubricant at the friction point. Lubricant feed is by means of lubrication equipment. The time period for relubrication is shorter than that for the lubricant change interval.

See
Lubrication method
Lubrication condition
Recirculating lubrication
Lubrication technology
One-off lubrication
Hydrodynamic lubrication
Lubricant change intervall
Lubricant change
Lubricant
Lubricant paste
Oil
Grease
Lubrication film
Lubrication system
in preference, as the lubricating grease
See
Lubricant
Grease cartridge
Fatty acids
can only be retained with difficulty in the axial bearing component.

 

Type NKX..-Z

 

The bearings have an end cap without lubrication
Feed of fresh lubricant to friction points. Fresh lubricant mixes with used lubricant at the friction point. Lubricant feed is by means of lubrication equipment. The time period for relubrication is shorter than that for the lubricant change interval.

See
Lubrication method
Lubrication condition
Recirculating lubrication
Lubrication technology
One-off lubrication
Hydrodynamic lubrication
Lubricant change intervall
Lubricant change
Lubricant
Lubricant paste
Oil
Grease
Lubrication film
Lubrication system
holes and are intended for grease
See
Lubricant
Grease cartridge
Fatty acids
lubrication ➤ section and ➤ Figure 5. The axial bearing component is greased using a lithium complex soap grease
See
Lubricant
Grease cartridge
Fatty acids
to GA08.

 
 

Needle roller/axial cylindrical roller bearings

 

Type NKXR, NKXR..-Z

Type NKXR

 

As the bearings do not have an end cap, the lubricating grease
See
Lubricant
Grease cartridge
Fatty acids
can only be retained with difficulty in the axial bearing component ➤ Figure 6. They should therefore be lubricated using oil
Fluid lubricant with a mineral oil and/or synthetic oil base, usually with active ingredients or additives.
in preference.

 

Type NKXR..-Z

 

Bearings of this type have an end cap without lubrication
Feed of fresh lubricant to friction points. Fresh lubricant mixes with used lubricant at the friction point. Lubricant feed is by means of lubrication equipment. The time period for relubrication is shorter than that for the lubricant change interval.

See
Lubrication method
Lubrication condition
Recirculating lubrication
Lubrication technology
One-off lubrication
Hydrodynamic lubrication
Lubricant change intervall
Lubricant change
Lubricant
Lubricant paste
Oil
Grease
Lubrication film
Lubrication system
holes and are intended for grease
See
Lubricant
Grease cartridge
Fatty acids
lubrication ➤ Figure 6. The axial bearing component is greased using a lithium complex soap grease
See
Lubricant
Grease cartridge
Fatty acids
to GA08.

 
 

Needle roller/angular contact ball bearings

Type NKIA, NKIB

 

Needle roller/angular contact ball bearings can be lubricated with oil
Fluid lubricant with a mineral oil and/or synthetic oil base, usually with active ingredients or additives.
or grease. For lubrication, the outer ring has a lubrication
Feed of fresh lubricant to friction points. Fresh lubricant mixes with used lubricant at the friction point. Lubricant feed is by means of lubrication equipment. The time period for relubrication is shorter than that for the lubricant change interval.

See
Lubrication method
Lubrication condition
Recirculating lubrication
Lubrication technology
One-off lubrication
Hydrodynamic lubrication
Lubricant change intervall
Lubricant change
Lubricant
Lubricant paste
Oil
Grease
Lubrication film
Lubrication system
groove and a lubrication
Feed of fresh lubricant to friction points. Fresh lubricant mixes with used lubricant at the friction point. Lubricant feed is by means of lubrication equipment. The time period for relubrication is shorter than that for the lubricant change interval.

See
Lubrication method
Lubrication condition
Recirculating lubrication
Lubrication technology
One-off lubrication
Hydrodynamic lubrication
Lubricant change intervall
Lubricant change
Lubricant
Lubricant paste
Oil
Grease
Lubrication film
Lubrication system
hole ➤ Figure 8 and ➤ Figure 9. If grease
See
Lubricant
Grease cartridge
Fatty acids
lubrication
Feed of fresh lubricant to friction points. Fresh lubricant mixes with used lubricant at the friction point. Lubricant feed is by means of lubrication equipment. The time period for relubrication is shorter than that for the lubricant change interval.

See
Lubrication method
Lubrication condition
Recirculating lubrication
Lubrication technology
One-off lubrication
Hydrodynamic lubrication
Lubricant change intervall
Lubricant change
Lubricant
Lubricant paste
Oil
Grease
Lubrication film
Lubrication system
is used, the radial and axial bearing components must be lubricated with the same grease
See
Lubricant
Grease cartridge
Fatty acids
prior to mounting the bearings.

 
 

Sealing

 
 

Combined needle roller
See Rolling element
bearings are not sealed. In the case of unsealed bearings, sealing
See Seals
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
    Gaseous, fluid, consistent, plastic or solid material for reduction of friction and wear between two friction elements.
    from the bearing.
 
   

Figure 13
Sealing of the bearing position in the adjacent construction – example

Symbole/00016410_mei_in_0k_0k.gif  Needle roller/axial deep groove ball bearing NX..-Z
Symbole/00016411_mei_in_0k_0k.gif  Sealing of the bearing with rotary shaft seal G

 

imageref_22438104459_All.gif

 
 

Bearings with end cap

End caps without lubrication
Feed of fresh lubricant to friction points. Fresh lubricant mixes with used lubricant at the friction point. Lubricant feed is by means of lubrication equipment. The time period for relubrication is shorter than that for the lubricant change interval.

See
Lubrication method
Lubrication condition
Recirculating lubrication
Lubrication technology
One-off lubrication
Hydrodynamic lubrication
Lubricant change intervall
Lubricant change
Lubricant
Lubricant paste
Oil
Grease
Lubrication film
Lubrication system
holes are suitable for grease
See
Lubricant
Grease cartridge
Fatty acids
lubrication

 

Bearings of design Z have an end cap, which grips the axial bearing component ➤ section and ➤ Figure 3, ➤ Figure 5 and ➤ Figure 6. End caps without lubrication
Feed of fresh lubricant to friction points. Fresh lubricant mixes with used lubricant at the friction point. Lubricant feed is by means of lubrication equipment. The time period for relubrication is shorter than that for the lubricant change interval.

See
Lubrication method
Lubrication condition
Recirculating lubrication
Lubrication technology
One-off lubrication
Hydrodynamic lubrication
Lubricant change intervall
Lubricant change
Lubricant
Lubricant paste
Oil
Grease
Lubrication film
Lubrication system
holes form a gap seal
A contact-free and friction-free seal, for example a sealing shield or end seal of a monorail guidance system
and retain the lubri­cating grease
See
Lubricant
Grease cartridge
Fatty acids
in the axial bearing component (applies to types NX..-Z, NKX..‑Z, NKXR..-Z).

 
 

Speeds

 
 

The product tables generally give two speeds for the 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 a bearing. Even under favourable mounting and operating conditions, this value should not be exceeded without prior consultation with Schaeffler    ➤ link. The values in the product tables are valid for oil
Fluid lubricant with a mineral oil and/or synthetic oil base, usually with active ingredients or additives.
lubrication.
 

Values for grease
See
Lubricant
Grease cartridge
Fatty acids
lubrication

 

For grease
See
Lubricant
Grease cartridge
Fatty acids
lubrication, 60% 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.

 
 

The thermally safe speed rating nϑr for NKXR, NKXR..-Z, NKIA and NKIB is given in the product tables. The speed rating nϑr to DIN ISO 15312:2004 is not defined for bearings NX and NKX and therefore only the limiting speed nG is given.

 
imageref_17757187211_All.gif   In order to calculate the thermally safe operating speed nϑ, NKXR(..-Z) must be regarded as axial bearings and NKIA, NKIB as radial 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
A measured relubrication interval can be achieved within given limits. The lubricant should be sufficiently thermally stable at the upper operating temperature and should not be too thick at the lower operating temperature.
of the bearings is limited by:

 
 
  • the dimensional stability of the bearing rings and rolling elements
  • the cage
  • the lubricant.
 
 

 

Possible operating temperatures of combined needler roller bearings ➤ Table 1.

 
   
Table 1
Permissible temperature ranges
 

Operating temperature
Combined needle roller
See Rolling element
bearings
Full complement ball type bearings, bearings with a sheet steel cage
The part of a rolling bearing which separates, retains and, where necessary, guides the rolling elements
or polyamide cage PA66
imageref_19988082955_All.gif
   
–30 °C to +120 °C

 
imageref_18348417035_All.gif   In the event of anticipated temperatures which lie outside the stated values, please contact Schaeffler.  
 

Cages

 

Sheet steel or plastic cages are used as standard

 

The cages of radial bearings are made from sheet steel or plastic and are closed on both sides ➤ dimension table. Bearings with a polyamide cage PA66 have the suffix TV. The cages for the axial bearing component are closed on both sides or open on one side. Sheet steel or glass fibre reinforced polyamide PA66 are used here as standard, depending on the bearing type.

 
imageref_18348417035_All.gif   For high continuous temperatures and applications with difficult operating conditions, bearings with sheet steel cages should be used. If there is any uncertainty regarding cage
The part of a rolling bearing which separates, retains and, where necessary, guides the rolling elements
suitability, please consult Schaeffler.
 
 

Internal clearance

 
 

Radial internal clearance of bearings with inner ring

The standard is CN

 

As standard, combined needler roller bearings with inner ring have the radial internal clearance CN (normal) ➤ Table 2. CN is not stated in the designation.

 
imageref_17757201419_All.gif   The values for radial internal clearance in bearings with an inner ring correspond to DIN 620-4:2004 (ISO 5753-1:2009) ➤ Table 2. These are valid for bearings which are free from load
Load which, for example, is to be supported at a friction point. Also strain from pressure and/or heat.

See Contact surface
and measurement forces (without elastic deformation).
 
imageref_18348417035_All.gif   For delivery options of bearings with a radial internal clearance value other than CN (for example C2, C3, C4) please consult Schaeffler.  
 

Bearings with inner ring

   

Bearings with inner ring

Table 2
Radial internal clearance of combined needle roller
See Rolling element
bearings with inner ring
 

Nominal bore diameter
Radial internal clearance
d
CN
mm
μm
over
incl.
min.
max.
- 24
20
45
24
30
20
45
30
40
25
50
40
50
30
60
50
65
40
70
65
80
40
75
80
100
50
85

 
 

Enveloping circle diameter Fw for bearings without an inner ring

For bearings without an inner ring, the enveloping circle diameter Fw is used

 

In the case of bearings without inner ring, the dimension for the enveloping circle diameter Fw is used instead of the radial internal clearance. The enveloping circle is the inner inscribed circle of the needle rollers
Cylindrical rolling elements with a high length/diameter ratio (DIN 5402 Part 3)
in clearance-free contact with the outer raceway. Once the bearings are mounted, the enveloping circle diameter Fw is in the tolerance class F6. The precondition for this is that the bore tolerances
See
Running accuracy
Dimensional accuracy
are observed for bearings without an inner ring ➤ section and ➤ Table 6. Deviations for the tolerance class F6 ➤ Table 3.

 
   
Table 3
Deviations for the enveloping circle diameter
 

Enveloping circle diameter Fw
Tolerance class F6
Tolerance for enveloping circle diameter Fw
mm
upper deviation
lower deviation
over
incl.
μm
μm
3
6
+18
+10
6
10
+22
+13
10
18
+27
+16
18
30
+33
+20
30
50
+41
+25
50
80
+49
+30
80
120
+58
+36
120
180
+68
+43
180
250
+79
+50
250
315
+88
+56
315
400
+98
+62
400
500
+108
+68

 
 

Dimensions, tolerances

 
 

Dimension standards

imageref_17757201419_All.gif   The main dimensions of combined needle roller
See Rolling element
bearings correspond to ISO 15:2017 (DIN 616:2000 and DIN 5429-1:2005). This excludes needle roller/axial deep groove ball bearings of the types NX and NX..-Z, which are not standardised.
 
 

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

 

The dimensional, geometrical and running tolerances
See
Running accuracy
Dimensional accuracy
of the bearings correspond to tolerance class Normal:

 
 
  • Radial bearing component in accordance with ISO 492:2014 and DIN 620-2:1988. Tolerance values in accordance with ISO 492 ➤ Table
  • Axial bearing component in accordance with ISO 199:2014 and DIN 620-3:1982. Tolerance values in accordance with ISO 199 ➤ Table .
 
 

This excludes:

 
 
  • NKIB, in this instance the bore d1 of the narrow inner ring and the width (–0,3 mm) over both inner rings
  • NKX and NKXR, in this instance the diameters D1, D2.
 
 

Suffixes

 
 

For a description of the suffixes used in this chapter ➤ Table 4 and medias interchange http://www.schaeffler.de/std/1D52.

 
   
Table 4
Suffixes and corresponding descriptions
 

Suffix
Description of suffix
TV
Bearing with radial cage
The part of a rolling bearing which separates, retains and, where necessary, guides the rolling elements
made from
glass fibre reinforced polyamide 66
Standard
XL
X-life bearing
Z
Bearing with end cap, axial bearing component greased with lithium complex soap grease
See
Lubricant
Grease cartridge
Fatty acids
to GA08

 
 

Structure of bearing designation

 

Examples of composition of bearing designation

 

The designation
Identification of a bearing by letters and numbers, indicating, for example, the series, dimensional series or size code, bore diameter, bearing design and information such as Corrotect plating or length of guideways
of bearings follows a set model. Examples ➤ Figure 14 to ➤ Figure 16. The composition of designations is subject in part to DIN 623-1    ➤ Figure.

 
   

Figure 14
Needle roller/axial deep groove ball bearing without inner ring, for grease
See
Lubricant
Grease cartridge
Fatty acids
lubrication:
designation structure


 

imageref_22443092363_en.gif

 
   

Figure 15
Needler roller/axial cylindrical roller bearing, with end cap, with recommended inner ring:
designation structure


 

imageref_22442654987_en.gif

 
   

Figure 16
Needle roller/angular contact ball bearing, double direction, with standard inner ring:
designation structure


 

imageref_22443094539_en.gif

 
 

Dimensioning

 
 

Equivalent dynamic bearing load

Separate calculation of the rating life
The basic rating life is the life reached or exceeded by 90% of a sufficiently large group of apparently identical bearings before the first evidence of material fatigue develops
for radial and axial bearing components

 

In the case of combined needle roller
See Rolling element
bearings, the rating life
The basic rating life is the life reached or exceeded by 90% of a sufficiently large group of apparently identical bearings before the first evidence of material fatigue develops
of the radial bearing and axial bearing component must always be calculated sep­arately ➤ Equation 1 and ➤ Equation 2. The lower value then applies in each case to the bearing position.

 

P = Fr and Fa respectively under purely radial load
A force which acts at an angle of b = 0°.
and purely axial load
Force acting in the direction of the shaft.
of constant magnitude and direction

 

The basic rating life
The basic rating life is the life reached or exceeded by 90% of a sufficiently large group of apparently identical bearings before the first evidence of material fatigue develops
equation L = (C/P)p used in the dimensioning of bearings under dynamic load
The term dynamic indicates that the operating condition is with the bearing rotating. This is not a variable load.
assumes a concentrically acting load
Load which, for example, is to be supported at a friction point. Also strain from pressure and/or heat.

See Contact surface
of constant magnitude and direction. In the case of radial bearings, this is a purely radial load Fr, while in the case of axial bearings it is a purely axial load Fa. In order to calculate the fatigue
Structural changes, apparent as surface delamination, caused by a large number of overrolling movements under load
rating life
The basic rating life is the life reached or exceeded by 90% of a sufficiently large group of apparently identical bearings before the first evidence of material fatigue develops
for combined needle roller
See Rolling element
bearings, the bearing load Fr or Fa(Pr = Fror Pa = Fa) is therefore used in the rating life
The basic rating life is the life reached or exceeded by 90% of a sufficiently large group of apparently identical bearings before the first evidence of material fatigue develops
equation for P ➤ Equation 1 and ➤ Equation 2.

 
 

Radial bearings

imageref_17757187211_All.gif   The radial component of the combined needle roller bearing
See Rolling bearing
may only be subjected to radial load. For the calculation of Pr➤ Equation 1.
 

Equation 1
Equivalent dynamic load
 
imageref_20969890187_All.gif

Legend

 
Pr
N
Equivalent dynamic bearing load
Load which, for example, is to be supported at a friction point. Also strain from pressure and/or heat.

See Contact surface
for the radial bearing
Fr
N
Radial load.
 
 

Axial bearing component

 

The axial bearing can only be subjected to axial load. For the calculation of Pa under a concentrically acting axial load➤ Equation 2.

 
imageref_17757187211_All.gif   For needle roller/angular contact ball bearings, the axial load Fa must not exceed 0,25 · Fr.  
 


Equation 2
Equivalent dynamic load
 
imageref_20969887115_All.gif

Legend

 
Pa
N
Equivalent dynamic bearing load
Load which, for example, is to be supported at a friction point. Also strain from pressure and/or heat.

See Contact surface
for the axial bearing component
Fa
N
Axial load.
 
 

Equivalent static bearing load

 

The equivalent static bearing load
See Equivalent static load
must be calculated for both the radial bearing and the axial bearing component ➤ Equation 3 and ➤ Equation 4.

 

Equation 3
Equivalent static load
 
imageref_20969906059_All.gif


Equation 4
Equivalent static load
 
imageref_20969910027_All.gif

Legend

 
P0r
N
Equivalent static bearing load
Load which, for example, is to be supported at a friction point. Also strain from pressure and/or heat.

See Contact surface
for the radial bearing
F0r
N
Largest radial load
A force which acts at an angle of b = 0°.
present (maximum load)
P0a
N
Equivalent static bearing load
Load which, for example, is to be supported at a friction point. Also strain from pressure and/or heat.

See Contact surface
for the axial bearing component
F0a
N
Largest axial load
Force acting in the direction of the shaft.
present (maximum load).
 
 

Static load
Load which, for example, is to be supported at a friction point. Also strain from pressure and/or heat.

See Contact surface
safety factor

S0a for needle roller/ angular contact ball bearings

 

In addition to the basic rating life L (L10h), it is also always necessary to check the static load
Load which, for example, is to be supported at a friction point. Also strain from pressure and/or heat.

See Contact surface
safety factor S0 ➤ Equation 5. The calculation must be carried out for both the radial bearing (S0r) and the axial bearing component (S0a). The axial static load
Load which, for example, is to be supported at a friction point. Also strain from pressure and/or heat.

See Contact surface
safety factor S0a must be > 1,5.

 

Equation 5
Static Load which, for example, is to be supported at a friction point. Also strain from pressure and/or heat.See Contact surface safety factor
 
imageref_27021597814984331_All.gif

Legend

 
S0r, S0a
Static load
Load which, for example, is to be supported at a friction point. Also strain from pressure and/or heat.

See Contact surface
safety factor
C0r, C0a
 N
Basic static load
Load which, for example, is to be supported at a friction point. Also strain from pressure and/or heat.

See Contact surface
rating
P0r, P0a
 N
Equivalent static bearing load.
 
 

Minimum load

 
 

Minimum radial load

In order to prevent damage
Loss of essential or required characteristics in equipment, machinery or plant or their component parts.
due to slippage, a minimum radial load
A force which acts at an angle of b = 0°.
of P > C0r/60 is required

 

In order that no slippage occurs between the contact partners, the radial bearing component must be constantly subjected to a sufficiently high load. For continuous operation, experience shows that a minimum radial load
A force which acts at an angle of b = 0°.
of the order of P > C0r/60 is necessary. In most cases, however, the radial load
A force which acts at an angle of b = 0°.
is already higher than the requisite minimum load
Load which, for example, is to be supported at a friction point. Also strain from pressure and/or heat.

See Contact surface
due to the weight of the supported parts and the external forces.

 
imageref_18348417035_All.gif   If the minimum radial load
A force which acts at an angle of b = 0°.
is lower than indicated above, please consult Schaeffler.
 
 

Minimum axial load

 

The axial component of the bearing arrangement
Arrangement of bearings, for example locating/locating, semi-locating/semi-locating, non-locating/non-locating, or semi-locating bearings in tandem, O or X arrangement
must be preloaded to 1% of the axial basic static load
Load which, for example, is to be supported at a friction point. Also strain from pressure and/or heat.

See Contact surface
rating C0a. Basic load
Load which, for example, is to be supported at a friction point. Also strain from pressure and/or heat.

See Contact surface
ratings C0a➤ dimension table.

 
 

Design of bearing arrangements

 

Support bearing rings over their entire circumference and width

 

In order to allow full utilisation of the load
Load which, for example, is to be supported at a friction point. Also strain from pressure and/or heat.

See Contact surface
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
The effective surface is the surface which separates the object from its surrounding medium.The actual surface is the approximate image from measuring technology of the ideal geometric surface. Note: various measuring processes or measuring conditions (e.g. stylus radius) can give different actual surfaces.The geometric surface is an ideal surface whose nominal form is defined by a drawing or other technical documentation. See DIN 4760 for further details.

See
Surface protection
Surface tension
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
The effective surface is the surface which separates the object from its surrounding medium.The actual surface is the approximate image from measuring technology of the ideal geometric surface. Note: various measuring processes or measuring conditions (e.g. stylus radius) can give different actual surfaces.The geometric surface is an ideal surface whose nominal form is defined by a drawing or other technical documentation. See DIN 4760 for further details.

See
Surface protection
Surface tension
should not be interrupted by grooves, holes or other recesses. The accuracy
Deviation of the actual dimension from the nominal dimension as described by tolerances. For monorail systems, the parallel deviation of the reference surfaces within given tolerances.

See
Running accuracy
Dimensional accuracy
of mating parts must meet specific requirements ➤ Table 5 to ➤ Table 8.

 
 

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 (shaft and housing
See Mounting dimenstions
bore) 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
Loss of essential or required characteristics in equipment, machinery or plant or their component parts.
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, mounting and dismounting options etc., must be taken into consideration in the selection of fits.

 
 

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

 
   
 

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
See Mounting dimenstions
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
See Mounting dimenstions
shoulders, retaining rings etc., are fundamentally suitable ➤ Figure 10, ➤ Figure 11 and ➤ Figure 18. For locating bearings and for bearings with a split inner ring (type NKIB), axial abutment of the bearing rings on both sides is particularly important.

 
 

Types NX and NX..-Z

Axial location by snap ring

 

With types NX and NX..-Z, the retaining ring is inserted in the annular slot in the bearing outer ring ➤ Figure 17. Snap rings which are inserted in the slot are a particularly compact and cost-effective way of locating the bearings axially in the housing. Suitable snap rings ➤ dimension table. The snap rings must be ordered in addition to the bearing.

 
   

Figure 17
Combined needle roller bearing NX with a retaining ring located axially in the housing

Symbole/00016410_mei_in_0k_0k.gif  Annular slot with retaining ring

 

imageref_22438107659_All.gif

 
 

Type NKX, NKX..-Z

 

The axial location of these bearings in one direction can take place by means of the needle roller bearing
See Rolling bearing
with integrated housing
See Mounting dimenstions
locating washer.

 
 

Dimensional, geometrical and running accuracy
Measured in terms of radial runout and axial runout, due to the dimensional and geometrical tolerances of the bearing in motion, defined according to DIN
of cylindrical bearing seats (bearings with inner ring)

 

Tolerance classes and surface designs for the shaft and the housing
See Mounting dimenstions
bore ➤ Table 5 and ➤ Table 6.

 
   
Table 5
Tolerance classes and surface design for the shaft – bearings with inner ring
 

Series
Shaft tolerance
Roundness tolerance
Parallelism tolerance
max.
max.
NKIA, NKIB
k6
IT4/2
IT4
NX, NKX, NKXR

 
   
Table 6
Tolerance classes and surface design for the housing
See Mounting dimenstions
bore
 

Series
Bore tolerance
to ISO 286-2
Roundness tolerance
Parallelism tolerance
max.
max.
NKIA, NKIB
M6
IT5/2
IT4
NX, NKX, NKXR
K6 Ⓔ,
M6 Ⓔ (for rigid bearing arrangements)

 
   
Table 7
Numerical values for ISO standard tolerances
See
Running accuracy
Dimensional accuracy
(IT grades) to ISO 286-1:2010
 

IT grade
Nominal dimension in mm
over
6
10
18
30
50
incl.
10
18
30
50
80
Values in μm
IT4

   
4
5
6
7
8
IT5

   
6
8
9
11
13
IT6

   
9
11
13
16
19
IT7

   
15
18
21
25
30

 
 

Roughness of cylindrical bearing seating surfaces

Ra must not be too high

 

The roughness
Regular or irregular repeat deviation from an ideal geometric profile.
of the bearing seats must be matched to the tolerance class of the bearings. The mean roughness
Regular or irregular repeat deviation from an ideal geometric profile.
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
The effective surface is the surface which separates the object from its surrounding medium.The actual surface is the approximate image from measuring technology of the ideal geometric surface. Note: various measuring processes or measuring conditions (e.g. stylus radius) can give different actual surfaces.The geometric surface is an ideal surface whose nominal form is defined by a drawing or other technical documentation. See DIN 4760 for further details.

See
Surface protection
Surface tension
➤ Table 8.

 
 

   
Table 8
Roughness values for cylindrical bearing seating surfaces – guide values
 

Nominal diameter
of the bearing seat
d (D)
Recommended mean roughness
Regular or irregular repeat deviation from an ideal geometric profile.
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

 
 

Mounting dimensions

The contact surfaces
The effective surface is the surface which separates the object from its surrounding medium.The actual surface is the approximate image from measuring technology of the ideal geometric surface. Note: various measuring processes or measuring conditions (e.g. stylus radius) can give different actual surfaces.The geometric surface is an ideal surface whose nominal form is defined by a drawing or other technical documentation. See DIN 4760 for further details.

See
Surface protection
Surface tension
for the rings must be of sufficient height

 

The mounting dimensions
Dimensions such as shaft diameter or hole distances, for example of bearings and guideways, which influence fitting for correct functioning
of the shaft and housing
See Mounting dimenstions
shoulders, spacer rings and retaining rings etc., must ensure that the contact surfaces
The effective surface is the surface which separates the object from its surrounding medium.The actual surface is the approximate image from measuring technology of the ideal geometric surface. Note: various measuring processes or measuring conditions (e.g. stylus radius) can give different actual surfaces.The geometric surface is an ideal surface whose nominal form is defined by a drawing or other technical documentation. See DIN 4760 for further details.

See
Surface protection
Surface tension
for the bearing rings are of sufficient height. Proven mounting dimensions
Dimensions such as shaft diameter or hole distances, for example of bearings and guideways, which influence fitting for correct functioning
for the radii and diameters of abutment shoulders are given in the product tables ➤ dimension table. These dimensions are limiting dimensions (maximum or minimum dimensions); the actual values should not be higher or lower than specified.

 
imageref_17757201419_All.gif   The transition from the bearing seat to the abutment shoulder
Shoulder in the surrounding structure for transfer of forces and location of components.
must be designed with rounding
See Mounting dimensions
to DIN 5418 or an undercut to DIN 509. The maximum chamfer dimensions for the inner rings in accordance with DIN 620-6 must be taken into consideration.
 

For NKX and NKXR, the axial bearing component seat must be free in the housing

 

In order to avoid double fits, the diameter of the contact surface
The contact surface between two bodies under load, calculated according to Hertz
for the housing
See Mounting dimenstions
locating washer in the adjacent construction
The immediate environment of the bearing; the bearing and adjacent construction have a reciprocal influence on each other
must be at least +0,5 mm larger than dimension D1 and D2 of the bearing washer in bearings NKX and NKXR ➤ Figure 18. Values for diameters D1 and D2➤ dimension table.

 
   

Figure 18
Free housing
See Mounting dimenstions
locating washer in the adjacent construction
The immediate environment of the bearing; the bearing and adjacent construction have a reciprocal influence on each other
for NKX and NKXR

D1 =  dimension of housing
See Mounting dimenstions
locating washer without end cap
D2 =  dimension of housing
See Mounting dimenstions
locating washer with end cap

 

imageref_22438126091_All.gif

 
 

Raceway for bearings without an inner ring (direct bearing arrangement)

Produce the raceway as a rolling bearing
Ready-to-fit machine element, often defined in standards, for transmitting movements, loads and tilting moments with a high level of efficiency; rolling bearings consist of rolling elements, cages and raceways on rings, guideways or carriages as well as lubricant and, if necessary, seals and accessories
raceway

 

Where needle roller
See Rolling element
bearings without an inner ring are used (so-called direct bearing arrangements), the rolling elements run directly on the shaft. In these bearings, the raceway for the rolling elements on the shaft must be produced as a rolling bearing
Ready-to-fit machine element, often defined in standards, for transmitting movements, loads and tilting moments with a high level of efficiency; rolling bearings consist of rolling elements, cages and raceways on rings, guideways or carriages as well as lubricant and, if necessary, seals and accessories
raceway (hardened and ground). Tolerances
See
Running accuracy
Dimensional accuracy
and surface designs are shown in ➤ Table 9. The surface hardness
Resistance of a body to indentation by another body; hardness is either intrinsic or is achieved by heat treatment processes (steel) and/or thermochemical diffusion; for rolling bearings, hardness is measured in Rockwell (HRC) or Vickers (HV)
of the raceway must be 670 HV to 840 HV, the hardening depth CHD or SHD must be sufficiently large. If the shaft cannot be produced as a raceway, the bearings can be combined with inner rings IR ➤ section and ➤ dimension table.

 
   
Table 9
Tolerance classes and surface design for the shaft (direct bearing arrangement) – without inner ring
 

Series
Shaft tolerance
Roundness tolerance
Parallelism tolerance
Recommended mean roughness
Regular or irregular repeat deviation from an ideal geometric profile.
value
Ramax (Rzmax)
max.
max.
μm
NX, NKX, NKXR
k6
IT3
IT3
0,1 (0,4)

 
 

Shaft raceway designed in accordance with DIN 617

imageref_17757187211_All.gif   If the surface of the shaft raceway is produced to DIN 617, the basic load
Load which, for example, is to be supported at a friction point. Also strain from pressure and/or heat.

See Contact surface
ratings Cr in the product tables must be reduced by 15%.
 
 

Steels for the raceway

 

Through hardening steels

imageref_17757201419_All.gif   Through hardening steels in accordance with ISO 683-17 (e.g. 100Cr6) are suitable as materials for rolling bearing
Ready-to-fit machine element, often defined in standards, for transmitting movements, loads and tilting moments with a high level of efficiency; rolling bearings consist of rolling elements, cages and raceways on rings, guideways or carriages as well as lubricant and, if necessary, seals and accessories
raceways in direct bearing arrangements. These steels can also be surface layer hardened.
 
 

Case hardening steels

imageref_17757201419_All.gif   Case hardening steels must correspond to DIN EN ISO 683-17 (e.g. 17MnCr5, 18CrNiMo7-6) or EN 10084 (e.g. 16MnCr5).  
 

Steels for inductive surface layer hardening

imageref_17757201419_All.gif   For flame and induction hardening, steels in accordance with DIN EN ISO 683-17 (e.g. C56E2, 43CrMo4) or DIN 17212 (e.g. Cf53) should be used.  
 

Raceway hardness
Resistance of a body to indentation by another body; hardness is either intrinsic or is achieved by heat treatment processes (steel) and/or thermochemical diffusion; for rolling bearings, hardness is measured in Rockwell (HRC) or Vickers (HV)
of less than 670 HV

imageref_17757187211_All.gif   If the raceway fulfils the requirements for rolling bearing
Ready-to-fit machine element, often defined in standards, for transmitting movements, loads and tilting moments with a high level of efficiency; rolling bearings consist of rolling elements, cages and raceways on rings, guideways or carriages as well as lubricant and, if necessary, seals and accessories
materials but the raceway hardness
Resistance of a body to indentation by another body; hardness is either intrinsic or is achieved by heat treatment processes (steel) and/or thermochemical diffusion; for rolling bearings, hardness is measured in Rockwell (HRC) or Vickers (HV)
is less than 670 HV, the load
Load which, for example, is to be supported at a friction point. Also strain from pressure and/or heat.

See Contact surface
on the bearing arrangement
Arrangement of bearings, for example locating/locating, semi-locating/semi-locating, non-locating/non-locating, or semi-locating bearings in tandem, O or X arrangement
cannot be as high as the full load
Load which, for example, is to be supported at a friction point. Also strain from pressure and/or heat.

See Contact surface
carrying capacity of the bearing. In order to determine the dynamic and static load
Load which, for example, is to be supported at a friction point. Also strain from pressure and/or heat.

See Contact surface
carrying capacity of the bearing arrangement, the basic dynamic load rating C of the bearings must be multiplied by the reduction factor fH (dynamic hardness
Resistance of a body to indentation by another body; hardness is either intrinsic or is achieved by heat treatment processes (steel) and/or thermochemical diffusion; for rolling bearings, hardness is measured in Rockwell (HRC) or Vickers (HV)
factor) and the basic static load rating C0r by the reduction factor fH0 (static hardness
Resistance of a body to indentation by another body; hardness is either intrinsic or is achieved by heat treatment processes (steel) and/or thermochemical diffusion; for rolling bearings, hardness is measured in Rockwell (HRC) or Vickers (HV)
factor) ➤ Figure 19 and ➤ Figure 20.
 
 

   

Figure 19
Dynamic hardness
Resistance of a body to indentation by another body; hardness is either intrinsic or is achieved by heat treatment processes (steel) and/or thermochemical diffusion; for rolling bearings, hardness is measured in Rockwell (HRC) or Vickers (HV)
factor at reduced hardness
Resistance of a body to indentation by another body; hardness is either intrinsic or is achieved by heat treatment processes (steel) and/or thermochemical diffusion; for rolling bearings, hardness is measured in Rockwell (HRC) or Vickers (HV)
of raceways/rolling elements

fH =  dynamic hardness
Resistance of a body to indentation by another body; hardness is either intrinsic or is achieved by heat treatment processes (steel) and/or thermochemical diffusion; for rolling bearings, hardness is measured in Rockwell (HRC) or Vickers (HV)
factor
HV, HRC =  surface hardness

 

imageref_9007203347547659_All.gif

 
   

Figure 20
Static hardness
Resistance of a body to indentation by another body; hardness is either intrinsic or is achieved by heat treatment processes (steel) and/or thermochemical diffusion; for rolling bearings, hardness is measured in Rockwell (HRC) or Vickers (HV)
factor at reduced hardness
Resistance of a body to indentation by another body; hardness is either intrinsic or is achieved by heat treatment processes (steel) and/or thermochemical diffusion; for rolling bearings, hardness is measured in Rockwell (HRC) or Vickers (HV)
of raceways/rolling elements

fH0 =  static hardness
Resistance of a body to indentation by another body; hardness is either intrinsic or is achieved by heat treatment processes (steel) and/or thermochemical diffusion; for rolling bearings, hardness is measured in Rockwell (HRC) or Vickers (HV)
factor
HV, HRC =  surface hardness
Symbole/00016410_mei_in_0k_0k.gif  Roller
Symbole/00016411_mei_in_0k_0k.gif  Ball

 

imageref_9007206737577355_All.gif

 
 

Determining the case hardening depth

Approximation value for case hardening depth

 

An approximation value for determining the minimum hardness depth
This depends essentially on the rolling element diameter, the material stress, the core strength and the hardening process
is given in ➤ Equation 6. The reference value for the load
Load which, for example, is to be supported at a friction point. Also strain from pressure and/or heat.

See Contact surface
present is the equivalent stress
Mechanical, mechanical-thermal, mechanical-chemical or tribological influences acting individually or jointly on a component
in accordance with the distortion energy hypothesis (DEH) as a function of the rolling element
Point or rotationally symmetrical bodies for transmitting loads between raceways.
diameter Dw and the magnitude of the load.

 

Equation 6
Case hardening depth
 
imageref_19497382667_All.gif

Legend

 
CHD
 mm
Case hardening depth
Dw
 mm
Rolling element diameter.
 
imageref_17757187211_All.gif   The local hardness
Resistance of a body to indentation by another body; hardness is either intrinsic or is achieved by heat treatment processes (steel) and/or thermochemical diffusion; for rolling bearings, hardness is measured in Rockwell (HRC) or Vickers (HV)
must always be above the local requisite hardness, which can be calculated from the equivalent stress.
 
 

Determining the surface hardening depth

imageref_17757187211_All.gif   In these surface hardening methods, the load
Load which, for example, is to be supported at a friction point. Also strain from pressure and/or heat.

See Contact surface
and contact geometry must be taken into consideration when determining the requisite hardening depth.
 
 

  For calculation of the surface hardening depth SHD ➤ Equation: 

Equation 7
Surface hardening depth
 
imageref_10856257163_All.gif

Legend

 
SHD
 mm
Surface hardening depth
Dw
 mm
Rolling element diameter
Rp0,2
 N/mm2
Yield point of base material.
 
 

Mounting and dismounting

 
imageref_17757187211_All.gif   The mounting and dismounting options for combined needle roller
See Rolling element
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

 

Combined needle roller
See Rolling element
bearings without an end cap 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
See Life, rating
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
Inspection, maintenance and repair of equipment and machines.
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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