The Installation of Rolling Bearings by Heating Method
Rolling bearings, as one of the main components of all kinds of machinery, are important parts for improving the stability and reliability of machines, and for reducing the overall running cost of machines. Therefore, in all kinds of machinery, how to install rolling bearings correctly is one of the most important tasks. There are many methods of bearing installation, and heating installation is one of them. The installation of rolling bearings by heating method can meet the requirements of high installation accuracy and ensure the safety of use.
The heating installation is mainly used in large and medium-sized rolling bearings. The installation process usually includes three steps: heating, assembling and cooling. The specific methods of these three steps are as follows: Firstly, heat the bearing by an external heating method，such as induction heating, hot oil bath heating or electric heat pipe heating etc, so that the bearing can reach an appropriate temperature（typically about 70℃ for rolling bearings）, then assemble the bearing onto the rotating shaft and/or housing, and finally cool down the bearing until totally cool
The purpose of heating installation is to reduce the interference fit during assembly and make the bearing more flexible. Both high temperature and low temperature will affect the accuracy of the fitting to a certain degree. Therefore, it is necessary to control the temperature of bearing and the object to be mounted. Generally, the temperature difference of bearing and the object to be mounted shall not exceed 20℃.
The advantages of bearing heating installation include: 1) The theoretical allowable relative axial displacement between inner and outer rings of bearing is larger than that of cold fitting installation. 2) The load capacity and fatigue life of the bearing are higher. 3) The thermal expansion and thermal deformation of bearing and the object to be mounted can be absorbed, so that the bearing can be mounted with higher accuracy, making it more suitable for the installation of large bearings. 4) The axial clearance of bearing can be precisely adjusted by controlling the heating temperature.
The disadvantages of bearing heating installation include: 1) The heating method is more expensive. 2) For the heating installation of small and medium-sized bearings, the temperature difference between them and the object to be mounted should not be too large due to bearing material restrictions. 3) It takes a lot of time to heat, assemble and cool.
In short, when selecting the installation method of bearing, it is necessary to consider the size of bearing, installation environment and requirements of accuracy and service life, so as to choose the most suitable installation method and ensure the normal use of bearing and the safety of equipment. Among all the installation methods, the heating installation can meet the requirements of high installation accuracy, and thus it is worth considering.
In summary, the installation of rolling bearings can be divided into many methods, and heating installation is one of them. Heating installation is suitable for large and medium-sized rolling bearings. The advantages include: the accuracy of the installation can be improved, the load capacity and life of the bearing are higher, and the axial clearance of bearing can be precisely adjusted by controlling the heating temperature. The disadvantage of heating installation is that the heating method is more expensive and it takes a lot of time. Therefore, when installing the rolling bearing, it is necessary to select the appropriate installation method according to the size of the bearing and the installation conditions.
