Motor bearings, also known as motor bearings or motor bearings, are special bearings for electric motors or motors.
Its main function is to support the rotating shaft of the motor and guide it to run smoothly while reducing friction. Common types of motor bearings include rolling bearings, sliding bearings, spherical bearings and oil-containing bearings. Among them, the most widely used are rolling bearings, which rely on internal rolling elements to complete their functions.
Working principle
Motor bearings reduce friction by rolling between the metal surfaces of the inner and outer rings through smooth metal balls or rollers. The rolling elements bear the load and support the motor shaft, so that the rotor of the motor can rotate smoothly.
Bearing type
Most small and medium-sized motors use rolling bearings, and large and medium-sized motors also use rolling bearings. Ball bearings (such as deep groove ball bearings) are used at both ends of the bearings of small motors. Medium-sized motors use roller bearings (such as cylindrical roller bearings and tapered roller bearings. Generally used in high-load situations) at the load end, and ball bearings are used at the non-load end (but the situation is the opposite, such as 1050kW motors). Rolling bearings are grease-lubricated and oil-lubricated.
Bearing installation
Whether the motor bearing is installed or not directly affects the bearing's accuracy, life and performance. Therefore, please fully study the bearing installation, that is, install the motor bearing according to the operating standards including the following matters.
● Clean the motor bearing and related parts. (For grease-lubricated bearings and double-sided oil seals or dust covers, sealed bearings, no cleaning is required before installation.)
● Check the size and finishing of related parts
Installation method
The installation of the motor bearing should be carried out according to the structure, size and matching properties of the bearing components. The pressure should act directly on the end face of the ring, and the pressure should not be transmitted through the rolling element. The following methods are generally used for the installation of motor bearings:
1. Press fit
When the inner ring of the motor bearing is tightly fitted with the shaft and the outer ring is loosely fitted with the bearing box hole, the motor bearing can be pressed onto the shaft with a press, and then the shaft and the bearing are installed into the bearing box hole together for press fit. On the end face of the inner ring of the motor bearing, a mounting sleeve made of soft metal material (copper or soft steel) is used.
When the outer ring of the motor bearing is tightly fitted with the bearing housing hole and the inner ring is loosely fitted with the shaft, the motor bearing can be pressed into the bearing housing hole first. At this time, the outer diameter of the assembly set should be slightly smaller than the housing hole diameter.
If the motor bearing ring is tightly fitted with the shaft and the seat hole, the inner ring and the outer ring should be pressed into the shaft and the seat hole at the same time during installation. The structure of the assembly set should be able to tightly fit the end faces of the inner ring and the outer ring of the bearing at the same time.
2. Heating fit
The installation method of heating the motor bearing or the bearing seat and using thermal expansion to convert the tight fit into a loose fit is a common and labor-saving installation method. This method is suitable for the installation of motor bearings with large interference. Before hot installation, put the ring of the motor bearing or the separable bearing into the oil tank and heat it evenly to 80-100℃, then take it out of the oil and install it on the shaft as soon as possible. To prevent the end face of the inner ring from being close to the shoulder after cooling, the motor bearing can be tightly fitted axially after cooling. When the outer ring of the motor bearing is tightly matched with the bearing seat made of light metal, the hot installation method of heating the bearing seat can avoid wear of the matching surface.
When heating the motor bearing with an oil tank, there should be a grid at a certain distance from the bottom of the box, or the motor bearing should be hung up with a hook. The motor bearing cannot be placed directly on the bottom of the box to prevent impurities from sinking into the motor bearing or uneven heating. There must be a thermometer in the oil tank to strictly control the oil temperature not to exceed 100℃ to prevent the tempering effect and reduce the hardness of the ring.
