FranBerLube™ Engineering & Technical Information
Engineering & Technical Information
For optimum performance it is important that the mating material is compatible with the bearing material. It should have a Brinell hardness at least 2.5 times that of the bearing material, usually obtainable by surface hardening or hard chrome plating. A superfine finish is not necessary and a good machined finish of 0.75 to 1.5 microns RA will usually suffice.
For high temperature applications or aggressive environments plated or stainless steels are preferable, but not austenitic steels, which are generally low in hardness and possess poor sliding properties.
Co-efficient of friction
Within the recommended PV range the coefficient of friction will be between 0.03 and 0.20, depending on the application. For design purposes a value of 0.14 may be used in most instances. Initial friction on start-up will approach the values for plain bearings.
Clearances and fits
FranBerLube™ bearings can be fitted using most of the techniques used for plain bearings, such as press fitting or interference fitting with locking screws. Shrink fitting is not recommended for certain types and cooling in liquid gases should always be avoided.
Running clearances will depend on individual applications but in general will be as for plain bearings.
In the absence of instructions to the contrary, bearings are normally produced for press fitting into cm H7 housing and receiving an f7 shaft.
Note: In most applications the use of wiper seals is optional, but they are not recommended where the motion is reciprocating since seals may remove essential surface lubricant and so reduce performance.
The optimum length of a FranBerLube™ bearing should be 1.5 times the effective diameter, although for large bearings this can be reduced to 0.35 times. For heavy loads the length should be increased rather than the diameter. Any thrust flanges or washers should be at least 3 mm (VB ins) thick.
||MINIMUM WALL THICKNESS
|13-24mm (9/16 -15/16 ins)
||3mm (1/8 ins)
|25-49mm (1-1 15/16 ins)
||5mm (3/16 ins)
|50-74 mm (2-3 ins)
||6.5mm (1/4 ins)
|75mm and over
||(Effective dia. in mm / 16) + 3mm (1/8 ins)
FranBerLube™ bearings should never be reamed or machined. The initial thin layer of lubricant is normally sufficient to allow bearings to be fitted and run-in but it is acceptable to apply a spray layer of molybdenum disulphide to the shaft if necessary.
Some surplus lubricant may be forced out as the shaft is fitted, and this can be minimised as well as assisting even dispersal of the lubricant by rotating the shaft. It is important to avoid shock or impact, which may damage the lubricant pockets.
||Slow moving bearings at temperatures up to 200°C. Very suitable for reciprocating motion. Effective in underwater applications. Approved by Nuclear Industry.
||Higher speed applications at up to 250°C. Resistant to moderate chemical action.
||Suitable for temperatures up to 400°C. Good chemical resistance. Available with any type of pockets.
||Ideal for temperatures up to 350°C. Excellent resistance to most forms of chemical attack. Available with plug type pockets only.
||Graphite free. Suits applications below 80°C for slow moving bearings. Ideal for marine applications.
If the removal of the shaft should ever become necessary, care should be taken to avoid damaging the lubricant pockets. If damage should occur FWB can usually carry out a repair. Before reassembling, the bearing and/or the shaft should be sprayed with air drying molybdenum disulphide.
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