Sintered bearings
Recommended bearing tolerances, shaft and running clearances.
Plain and flanged bearings.
| Housing Ds | Bearing d/D | Insertion pin (Dp) | Bore after fitting dj | Shaft Da |
| H7 | E7/r7 | s5 | F7 | h8, h9 |
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Sintered products by Lagermetall AB
Stocked items (> 300 standard stock sizes)
- Plain ESSEM oil-bronze bearings acc. to SS 2991
- Flanged ESSEM oil-bronze bearings acc. to SS 2992
- Solids in oil-bronze (up to Ø 80 mm)
- Solids in graphite-bronze (up to Ø 80 mm)
- Filters (for cleaning liquid and gases and for silencing functions)
- Spherical bearings in ESSEM oil-bronze quality
Non-stocked items (produced and stocked only on clients request)
- ESSEM Ferro-bronze products
- ESSEM Graphite-bronze bearings (for high temperatures)
- ESSEM Oil-steel bearings
- ESSEM Lead-bronze bearings
- Bearings with special lubrication (for heat, high friction etc.)
- Bearings according to customer drawings
Corresponding standards (similar to SS 2991 and SS 2992)
ISO ISO 5755/1
Germany Sint A51
USA SAE 840, ASTM B 438 grade1 type1, MPIF CTG-1001-K17
Machining of sinterbronze bearings
Machining of self-lubricating bearings should be avoided whenever possible in order to maintain the best bearing properties. When machining is absolutely unavoidable it is important that the recommendations below are followed. Machining should be carried out with the bearing impregnated with oil.
ESSEM Oil-bronze, ESSEM Ferro-bronze and ESSEM Graphite-bronze can be turned but not the bearing face on steel. Diamond or carbide tips, quality ISO K 20, with a tip radius of max. 0,1-0,2 mm should be used for final turning.
Suitable cutting speeds are : 100-200 m/min. for ESSEM Oil-bronze and ESSEM Graphite-bronze .
For ESSEM Ferro-bronze we recommend 50-100 m/min.
The bearing surface of self-lubricating bearings must not be grinded as the oil transportation pores then will close. The outer surface of the bearing can, however, be machined in any way required. If external additional lubrication is used then even the pores on the outside diameter must be kept open.
The bearing can be heated on an electrical hot plate after machining to check that the pores are still open. Oil will then ooze out of the bearing.
Bearings usually lose oil during the turning operation and the lost oil should be replaced before the bearing is used again. A simple method of doing this is by immersing the bearing in oil SAE 20, heated up to 80° C. The bearing should be immersed until the oil has cooled off.The pores are filled with oil by this process and the bearing is once again ready for use.
The edge strength of graphite-bronze is rather low and special care should therefore be taken when turning end surfaces.
Technical information on sintered bearings
| Productname Mechanical properties |
Oil-bronze Alloy 630 |
Ferro-bronze Alloy 611 |
Oil-steel Alloy 100 |
| Status at Lagermetall AB |
Stock-item (booklet available) |
Non-stocked item (produced against order) |
Non-stocked item (produced against order) |
| P-max. (N/mm 2 ) static load, 0,1 % deformation | 50 N/mm² | 50 N/mm² | 50 N/mm² |
| Oil content, volume % | 25 | 20 | 25 |
| Ultimate tensile strength, Rm N/mm² | 60 | 100 | 60 |
| Hardness, Vickers, HV5 | 15 HV | 40 HV | 20 HV |
| Linear expansion, · 10 -6 / K | 18 | 15 | 12 |
| Thermal conductivity, W / m · K | 40 | 35 | 30 |
| Tolerances standard (Inner diameter / Outer diameter + Length) | E7 / r7 + h13 (Od < Ø50) E8 / r7 + h14 (Od >Ø50) |
Acc. to drawing | Acc. to drawing |
| Area of use for different sintered bearings | Standard- applications |
By demanding applications | For lower production- costs at large series |
| Rec. working-temp./max. (can be increased by special oil or grease) | 90 °C | 90 °C | 90 °C |
Assembly
The sintered bearings are porous and can be damaged if fitting is not carried out correctly. Assembly by hammer blows deforms the bearing. The correct method is by using a shouldered insertion pin.
When the recommended interference between housing and bearing (H7/r7) is used the shrinkage of the inner diameter will be 0,5-0,6 times the interference.
Fitting without the use of an insertion pin can only be done where a tolerance of more than IT8 is acceptable on the fitted bearing.
Insertion force required per mm 2 of outside surface area:
ESSEM Oil-bronze - approx. 3N
ESSEM Graphite-bronze - approx. 2N
ESSEM Ferro-bronze - approx. 5N
Bonding / Glueing
It is also possible to fit selflubricating bearings with Loctite or similar adhesives. The outer surface of the bearing should be degreased before bonding (glueing).
Note that only the outer surface should be degreased and therefore degreasing-apparatus cannot be used.
Additional lubrication
No extra lubrication is usually required but can be provided where speeds, loads or temperatures are high. For further information, please contact us.
