Bearing assembly - installation
push into
Pressing is one of the easiest installation methods for small and medium-sized bearings. For bearings with a small interference, an equal pressure press can be applied to the circumference of the raceway at normal temperature. When mounting non-separable bearings on the shaft and bearing housing at the same time, use a horn on the bearing and apply equal pressure to the inner and outer rings to press it in.
Precautions
●If the pressure during press-in is too large, burns and cracks may occur due to too small internal clearance of the bearing.
●Insufficient impact load during installation may cause indentation and damage.
● When installing, take care to prevent foreign matter from entering the mating surface.
Hot loading
Under no circumstances should the temperature of the bearing be heated above 120 °C. The bearing is immersed in the heated clean oil. At this time, the management of the oil temperature becomes very important, and the heating temperature must not exceed 120 °C. However, this method is not applicable to bearings with a dust cap type and a seal type that have been filled with grease.
The general method of heating a bearing is:
1) In the case where the bearing is immersed in heated clean oil for heating, in order to prevent uneven heating, the bearing may be placed on the wire mesh or suspended in oil to heat.
Do not use a burner to heat the bearings. The heating method may cause local heating of the bearing, which may cause damage to the bearing and shorten the life.
2) Heating the bearing in the atmosphere using a thermostatic bath or the like
The bearing in the dry state can be taken directly, but it takes a certain time for the bearing to heat up, so use a contact thermometer or the like to measure the temperature of the bearing to ensure that the bearing does rise to the target temperature.
3) Method of heating bearing by induction heating device
Compared with oil bath heating method and constant temperature bath heating method, it is safe, clean, and quick. The induction heating device consists of an iron frame wound with multiple coils.
When a current passes through the primary coil (low voltage coil), the coil generates a magnetic field, and a current is generated at a bearing equivalent to the secondary coil (high voltage coil) of the transformer. When a strong low-voltage AC current is passed through the bearing, the non-metallic parts and devices remain at a low temperature, and only the bearing heats up in a short time.
The bearing is magnetized by induction heating and demagnetized after heating.
4) Hydraulic installation
When installing a large bearing with a tapered bore, it is difficult to install by tightening the retaining nut (screw). In this case, a hydraulic mounting method is required. Specifically, a hydraulic pressure is applied to the gap between the bearing and the shaft to form an oil film. It can reduce the friction during installation and is easy to tighten. 2 Inject high-pressure oil into the hydraulic nut to generate the axial force (thrust) required for installation. If you need to make the bearing installation easier.
The above two operations can be performed simultaneously. The residual clearance after the bearing is installed can be confirmed by the feeler gauge or the axial rear thrust measurement of the inner ring during installation.
Hot loading precautions
● The main point of hot loading is to complete in a short time.
● After inserting the heated bearing into the shaft, continue to press the inner ring and shoulder until the bearing cools. In addition, after cooling to normal temperature, tighten the bearing by stamping or the like.
● In the event that the bearing cannot be installed continuously during the hot loading operation, stop the operation and remove the bearing.
●When installing, apply an abrasion inhibitor to the mating surface of the shaft or bearing chamber and the bearing to prevent rust.
If you need to use heated bearings, wear heat-resistant gloves for safety.
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