When should I use C over Montage

intact. Ludwig Meister's blog

Thermal assembly is the gentlest way to position a cylindrical bearing on a shaft. In order to overcome the press fit that is usually present, it is necessary either to make the shaft cold or to heat the bearing inner ring of the roller bearing. Due to this temporary expansion, you can playfully push the bearing over the shaft and then let it cool down at the appropriate point and thus obtain the desired press fit. This temperature difference can be produced in different ways.

Possibilities of heating rolling bearings

The easiest options are Heating plates or Hotplates. However, the classic three-stage hotplate reaches a maximum temperature, which is harmful to the bearings and should therefore only be used to a limited extent. Temperature-adjustable heating plates make it possible to bring the bearing exactly to the desired temperature without damaging it.

There is another possibility Heating cabinetswhich also allow very fine temperature control. A possible alternative in the private household are here Ovenswhich also allow very precise temperature controls and thus gently heat the bearing. The disadvantage of these methods, however, is a somewhat longer heating time.

A final option for heating bearings well is what is known as inductive heating. With modern inductive heating devices you can bring bearings to the right temperature very quickly within a short period of time. A great advantage of induction heaters is that the inner ring becomes warmer than the outer ring, which means that the bearing can then be processed much more quickly.

Burners, open flames and hot air blowers generate high temperatures at very specific points, which are not suitable for the bearings. These heating methods also bring dirt into the bearings, which ultimately leads to the bearings failing prematurely. They should therefore not be used.

Ways to cool off waves

To make the wave cold, you can next Cooler sprayDry ice be used. The shaft is cooled down to such an extent that it contracts and the bearing can be easily mounted over it. However, the problem here is that the cold wave very easily creates condensation, which ultimately leads to rust formation.

The right heating temperature for mounting bearings

The heating temperature required for mounting bearings depends on many factors. One of the most important factors is the shaft size or the fit of the shaft. The larger the shaft dimension, i.e. the greater the excess with which the bearing is to be joined to the shaft, the warmer the bearing must be made. Further influencing factors are, for example, "Where do I warm up my bearing?" Or "How long is the sliding path over the shaft?", Because these two factors also cool the bearing down.

Measure the storage temperature

When I have found out what is the optimal temperature for my bearing assembly, the question often arises, how can I measure it? The easiest way to do this is with a contact thermometer. Many people also try to measure bearing temperatures with infrared thermometers, but an error often occurs here: Due to the reflective surface of the roller bearings, the emissivity of these thermometers would have to be changed, which is usually not known. Measurement errors of 30 ° C are easily possible.

Maximum allowable temperature

The maximum permissible temperature to which a bearing can be heated depends on which bearing component has the lowest permissible temperature. In addition to the lubricant, which has a strong influence and can sometimes only be heated to 100 ° C, the focus is on the seals, which are usually at a peak temperature of around 120 ° C, but also cages, also with a peak temperature of around 120 ° C, and the roller bearing steel. Rolling bearing steel is often underestimated. This is a hard steel that must not be overheated after the hardening process. There are bearings that, due to the rolling bearing steel, must not be heated above 100 ° C.