Ball bearing wiki: Technical information about ball bearings

Ball bearings consist of an inner and outer race, a cage and rolling elements. The cage is there to separate the rolling elements, in the form of balls, from each other. If the balls were not separated, they would run against each other and overheat. This would have destructive effects at high rotational speeds and friction of the balls. But how do the balls get into the ball bearing?

Option 1:

This question is easy to answer when looking at a deep groove ball bearing according to DIN 625, as these have noticeable indentations on the inner and outer race. If the inner and outer races are moved towards each other up to the respective recess, the balls can easily be filled into the grooves and fixed with the cage. In this case, the cage takes over the function of preventing the balls from falling out.

Option 2:

Heating the outer ring and cooling the inner ring for smaller metal bearings down to miniature designs is also unusual, but practised in the industry. The balls and cages can then be easily inserted into the space created between the inner and outer race. If the materials of the race contract or expand again, the ball bearing has reached its standard dimensions and all the balls are in place. For igus, only the first option comes into question, but there are also others, which are illustrated below.

Many metallic rolling bearings are available in a sealed version. Ball bearing seals are generally mandatory for the metallic version, as otherwise contamination can combine with the lubricant and thus block the running of the bearing. Should the ball bearing be open or closed? This depends on the ball bearing type.

Metallic bearings must be protected:

Metallic ball bearings are also available as open types. However, these are only used very rarely due to the problems mentioned above. Therefore, a dusty environment is sufficient to negatively influence the running properties over a longer period of time.

Metallic ball bearings are sealed according to the shaft seal principle. These seal designations are possible:

• Z = one-sided sheet metal cover disc with gap seal
• ZZ/2Z = as above, from both sides
• RS = single-sided, sliding rubber seal
• LB = as above
• 2RS = as above, from both sides
• LLU = as above, non-contact rubber seal, from both sides
• EE = as above, from both sides contacting, abrasive
• RZ = one-sided, non-contact rubber seal
• LB = as above
• 2RZ = as above, from both sides
• LLB = as above

The seal designations are valid worldwide and, depending on the manufacturer, usually appear as a suffix after the respective DIN installation size.

Without ball bearings, the world wouldn't really turn, would it?

Because we simply see the world as it is. Everything grows and develops, is in motion and is taken for granted. However, people hardly think about such a marvel of technology: The ball bearing. We encounter it every day in our lives, whether we are travelling to work by bike, train, bus or car. There are ball bearings in all means of transport, but also in kitchen appliances, training equipment in the gym or at the bowling alley in the evening – we find rolling bearings everywhere. But what are they anyway? Since the development of the steam engine and the beginning of industrialisation, ball bearings have become an integral part of our everyday lives.

Ball bearings are bearing components that reduce the frictional resistance caused by rolling bodies between an inner race and an outer race. They are used to fix axles and shafts in place and can absorb radial and/or axial forces, depending on the type. Due to their design, they also allow the shaft or other components that are mounted on an axle, such as a wheel, to rotate.