Application
Bearing function
In terms of its function, it should be support, that is, it is used to support the shaft literally, but this is only part of its function. The essence of support is to be able to bear radial loads. It can also be understood as it is used to fix the shaft. The automatic selection of bearings is included. It is to fix the shaft so that it can only achieve rotation, while controlling its axial and radial movement. The motor cannot work at all without bearings. Because the shaft may move in any direction, and the motor is required to only rotate when it is working. Theoretically speaking, it is impossible to achieve the role of transmission. Not only that, but the bearing will also affect the transmission. In order to reduce this effect, good lubrication must be achieved on the bearings of the high-speed shaft. Some bearings are already lubricated, which are called pre-lubricated bearings. Most bearings must have lubricating oil, which is responsible for not only increasing energy consumption due to friction when running at high speeds, but even more frighteningly, it is easy to damage the bearings. The idea of ​​turning sliding friction into rolling friction is one-sided, because there is something called a sliding bearing.
Lubricating
The lubrication purpose of rolling bearings is to reduce the internal friction and wear of the bearing, to prevent burning; to extend its service life; to discharge frictional heat and cooling, to prevent the bearing from overheating, and to prevent the lubricating oil from aging; also to prevent foreign matter from intruding into the bearing, or to prevent rust and corrosion The effect.
Lubrication method
Bearing lubrication methods are divided into grease lubrication and oil lubrication. In order to make the bearing function well, first of all, it is necessary to choose a lubrication method suitable for the use conditions and purpose. If only lubrication is considered, the lubricity of oil lubrication is dominant. However, grease lubrication has the advantage of simplifying the structure around the bearing. The advantages and disadvantages of grease lubrication and oil lubrication are compared. Pay special attention to the amount when lubricating, whether it is oil lubrication or grease lubrication, too little lubrication and insufficient lubrication will affect the life of the bearing, and too much will produce large resistance and affect the speed.
Seal
The sealing of the bearing can be divided into two types: self-sealing and external sealing. The so-called bearing with its own seal is to make the bearing itself into a device with sealing performance. Such as bearings with dust caps, sealing rings, etc. This kind of seal occupies a small space, is convenient to install and disassemble, and the cost is relatively low. The so-called bearing with external sealing performance means that a sealing device with various performances is manufactured inside the installation end cover and so on. Bearing external seal is divided into two types: non-contact seal and contact seal. Among them, the non-contact seal is suitable for high-speed and high-temperature occasions, and has different structural forms such as gap type, labyrinth type and gasket type. Contact seal is suitable for medium and low-speed working conditions. Commonly used structural forms such as felt seal and cup seal.
According to the requirements of the bearing working condition and working environment for the degree of sealing, various sealing forms are often used in engineering design to achieve better sealing effect. The following main factors should be considered in the selection of bearing external seal:
Bearing lubricants and types (grease and lubricating oil);
The working environment of the bearing and the size of the space occupied;
Advantages of the shaft support structure, allowing angular deviation;
The circumferential speed of the sealing surface;
The operating temperature of the bearing;
manufacturing cost.