Lubrication

The lubrication is a whole of techniques making it possible to reduce the Frottement, the wear between two parts in contact and, moving one compared to the other. It often makes it possible to evacuate part of the thermal energy generated by this friction, like avoiding corrosion…

In Mechanical, one lubricates the parts of Métal or Céramique with a greasy substance, like Huile or grease. The lubricating are liquid, pasty products or solids of origin mineral (Hydrocarbure S essentially), animal, vegetable or synthetic.

In Biology, lubrication intervenes in the form of production, by the Muqueuse S concerned, of a Mucus containing water. It also intervenes in the operation of the articulation S which count among the best “slipping” mechanisms than one knows.

Modes of lubrication

There exists several manner of bringing the lubricant between the parts moving.

Specific lubrication

The first method consists in putting the lubricant before the movement or during the movement. That can be done in a manual way, for example by depositing oil drops with a oil-can, while placing grease with the fingers (if this one is not toxic), or by applying the lubricant with a brush. It is for example the case of the lubrificaiton of a chain of Vélo, hinges of a door… This lubrication can be also carried out by projection using a Aérosol (bends).

But this specific lubrication can also be done in an automatic way, in general in the form of aerosol; it is the case for example of the Usinage with a turn with numerical control.

In the case of an automatic lubrication, the apparatus can be equipped with an oil collecting tray which makes it possible to reprocess the lubricant in excess or worn. In the case of a manual lubrication, the lubricant in excess or worn is often lost in nature, which can pose environmental problems (although the quantities are in general weak for the domestic uses).

Surface prélubrifiée

The manufacturer of the part can also deliver a prélubrifiée part. It is the case for example of the majority of the Préservatif S or certain machine elements. In certain cases, portions of a piece are voluntarily porous, the pores being used as lubricant reserve.

In the case of a liquid or pasty lubricant, this prelubrification is effective only for one limited time. In the case of a solid coating it remains effective as long as the layer of lubricant is adherent and in good state.

Continuous food

In the case of a closed device, it is possible to have a lubricant tank (liquid). A Pompe ensures the circulation of the lubricant towards the parts moving and the lubricant turns over towards the tank when the device is with the stop. It is the case in particular of oil for the engine spark-ignition . The lubricant is degraded and taken care out of remains of wear, it is thus necessary to drain the tank regularly and to fill it with new lubricant.

In the case or the device is fed in liquid, one can put lubricant in the liquid; it is for example the case of the oil which one adds in the Carburant intended for the driving for two times.

One can also make soak mechanics in a liquid lubricant, one speaks then about “bath of oil” or Barbotage. The Carter should not in no case to be completely filled.

See too

• Tribology

• the wikilivre of tribology.