Lubrication Selection

• When two bearing surfaces are correctly lubricated, they are separated by a thin film of oil.
• When two bearing surfaces are correctly lubricated, they are separated by a thin film of oil.
• The purpose of lubricating surfaces is to eliminate the friction between them and to introduce a fluid whose reaction to friction is very small.
• The purpose of lubricating surfaces is to eliminate the friction between them and to introduce a fluid whose reaction to friction is very small.
• No matter how smooth the surfaces in contact are made, they always retain a certain amount of roughness and unevenness, this is known as friction.
• No matter how smooth the surfaces in contact are made, they always retain a certain amount of roughness and unevenness, this is known as friction.
• An efficient lubricant is one which is able to hold its thickness of film and not be broken down under load or temperature.
• An efficient lubricant is one which is able to hold its thickness of film and not be broken down under load or temperature.
• An efficient lubricant must not offer too much resistance in motion.
• An efficient lubricant must not offer too much resistance in motion.
• The thicker the oil, the greater the fluid friction.
• The thicker the oil, the greater the fluid friction.
• The thicker the oil, the greater the fluid friction.
• When using lubricants ensure that the oil is "thick" enough so that the film is not broken, but "thin" enough not to induce excessive fluid friction.
• When using lubricants ensure that the oil is "thick" enough so that the film is not broken, but "thin" enough not to induce excessive fluid friction.
• Lubricant should also not gum up, since it loses its fluidity and collects dust and grit.
• Lubricant should also not gum up, since it loses its fluidity and collects dust and grit.
• The gumming up of the lubricant will increase friction and wear.
• The gumming up of the lubricant will increase friction and wear.
• The lubricant shouldn't have any acidity.
• The lubricant shouldn't have any acidity.
• Requirements of an efficient lubricant:

  • Should be able to hold its thickness of film and not be broken down under load or temperature.
  • Must not offer too much resistance in motion.
  • Should be "thick" enough to not brake the film.
  • Should be "thin" enough to not induce excessive fluid friction.
  • Should not gum up.
  • Should be without any acidity.
• Requirements of an efficient lubricant:

  • Should be able to hold its thickness of film and not be broken down under load or temperature.
  • Must not offer too much resistance in motion.
  • Should be "thick" enough to not brake the film.
  • Should be "thin" enough to not induce excessive fluid friction.
  • Should not gum up.
  • Should be without any acidity.
• When choosing a lubricant, consider the following:

  • Price of the lubricant.
  • Rubbing pressure between the two surfaces.
  • Rubbing speed of the two bearing surfaces.
  • Temperature to which the lubricant will be exposed.
  • Clearance between the two surfaces.
• When choosing a lubricant, consider the following:

  • Price of the lubricant.
  • Rubbing pressure between the two surfaces.
  • Rubbing speed of the two bearing surfaces.
  • Temperature to which the lubricant will be exposed.
  • Clearance between the two surfaces.
• The lubricant should have a good deal of body (viscosity or thickness) for heavy pressures, while less body is necessary for lighter pressures.
• The lubricant should have a good deal of body (viscosity or thickness) for heavy pressures, while less body is necessary for lighter pressures.
• The lubricant should possess a good deal of fluidity for rapid speeds, while less fluidity is recommended for slow speeds, to prevent wastage.
• The lubricant should possess a good deal of fluidity for rapid speeds, while less fluidity is recommended for slow speeds, to prevent wastage.
• To prevent the lubricant from being decomposed by heat, the flash point of the oil or grease should be greater than the maximum temperature which is reached.
• To prevent the lubricant from being decomposed by heat, the flash point of the oil or grease should be greater than the maximum temperature which is reached.
• Ball and roller bearings do not require oil or grease, but some lubricant is needed to prevent the highly polished surfaces from rusting and to help prevent dirt from entering the housing.
• Ball and roller bearings do not require oil or grease, but some lubricant is needed to prevent the highly polished surfaces from rusting and to help prevent dirt from entering the housing.