In accordance with the requirements of the use of graphite bearings can be used in the following three ways to install.
1 shrinkage mounting method
The method is mainly used in PV large bearing. It is well known that the graphite bearing has a lower coefficient of thermal expansion and elastic modulus, it is difficult to keep it firmly in the metal sleeve. Therefore, only the beginning of high tolerance to go in, for this, the cold state bearings can be loaded into a pre heated to a certain temperature of the metal sleeve. The preheat temperature should not be less than the maximum operating temperature. The metal sleeve is then cooled to shrink, so that a certain pressure is generated, and the bearing is fixed.
When using this installation method, attention should be paid to:
1) bearing must be in contact with the outer circular surface completely and bearing, otherwise it may crush the bearing.
2) to accurately select the processing size of carbon graphite bearings, even in the maximum operating temperature, it should also make the shaft bearing a certain residual stress.
3) using this installation method, in consideration of bearing bearing materials, should try to make bearing bearing always have a certain pressure on the bearing. To this end, it is best to use and bearing with the same (or close to) the coefficient of thermal expansion of the material to manufacture the bearing bearing (that is, the bushing).
4) when the bearing is used at 250qC or more than 250 degrees Celsius, the bearing seat L bushing should have a very low coefficient of thermal expansion, in order to avoid damage to the bearing. Especially for small bearings, but also to pay attention to, it is best to choose low carbon steel and other thermal expansion coefficient of small materials to do bearing bushing.
Experience has shown that when the bearing outer diameter is 25 mm, the fit gap is negative 0.1 - 0.15 mm is suitable. When the shrink fitted loquat bearing mounted to the phosphorus or aluminum bronze (or with the same high coefficient of thermal expansion of materials) of the bearing sleeve, should absolutely avoid exceeding the allowed temperature range.
2 pressure mounting method
The method is suitable for the case that the diameter of graphite bearing is small and the range of temperature range is not large. When this installation method is used to ensure that the bearing and bearing sleeve is absolutely flat and pressure stability.
3 loose fitting method
This method is only applicable to the case of the load bearing. When installing, the graphite bearing is allowed to rotate in the sleeve, in order to prevent the left and right transmission, and also can be fixed with one key.