Bearings are indispensable parts in mechanical equipment. Bearings have different forms in different mechanical equipment, and their functions and roles are different. The structural rollers inside the cylindrical roller bearing are arranged in parallel, the cylindrical roller and the raceway are the first contact bearings, the load capacity is large, mainly bear radial load.
The friction between the rolling body and the rim of the ferrule is small, suitable for high-speed rotation, cylindrical roller bearings with no rim of the outer ring or inner ring. The inner ring and the outer ring can move relative to the axis, and can be used as free-end bearings.
The bearing has the following characteristics:
The processing requirements of the shaft or seat hole are higher, and the relative deflection of the outer ring axis should be strictly controlled after the installation of the bearing, so as not to cause contact stress concentration. Roller and raceway for line contact or repair line contact, radial bearing capacity is large, suitable for bearing heavy load and impact load. N type and NU type can move axially, can adapt to the change of the relative position of the shaft and housing caused by thermal expansion or installation error, can be used as free end support. Low friction coefficient, suitable for high speed, limit speed close to deep groove ball bearings.
The characteristics are:
The raceway and the rolling body of the cylindrical roller bearing are of geometric shape. After the improved design, it has a high bearing capacity. The new structural design of the guard and the roller end face not only improves the axial bearing capacity of the bearing, but also improves the lubrication conditions of the contact area between the roller end face and the guard, and improves the service performance of the bearing.
The accuracy levels of cylindrical roller bearings can be divided into:
PO,P6, P5,P4, P2. The accuracy levels are ranked from low to high. The materials used to manufacture bearing components have a great impact on the reliability and performance of bearings. Considerations for bearing rings and rolling bodies include fatigue resistance under rolling contact and lubrication conditions of different cleanliness, hardness in relation to bearing capacity, and dimensional stability.
Installation method and installation precautions of rolling bearings
Installation of rolling bearings Whether the installation of bearings is correct directly affects the accuracy, life and performance of bearings in use. Therefore, the design and assembly department should fully study the installation of bearings in accordance with the operating standards.
Operating standard items are usually as follows:
1. Clean bearings and related parts
2. Check the size and accuracy of relevant parts and components
3. Installation
4. Check the bearing after installation
5. Fill lubricant
First, bearing oil heating installation precautions
1, bearing heating ゚ ゚ 90 C - 100 C is more than 120 ゚ C.
2. In order to make the bearing not touch the bottom of the oil groove, the bearing should be placed on the metal grid, or lifted.
3, in order to prevent the operation, because the inner ring temperature drops and is difficult to install, heating the bearing should be 20°C - 30°C higher than the required temperature.
4. After installation, the bearing will cool down and shrink in the width direction, so it should be locked with shaft nuts or other appropriate methods to prevent the gap between the inner ring and the bearing shoulder.
Second, operation check after the installation of bearings, in order to check whether the installation is correct, operation check should be carried out.
1, small machinery can be rotated by hand to confirm whether the rotation is smooth. Check items are due to foreign bodies, scars, indentation caused by poor operation, due to poor installation, installation seat processing caused by unstable torque, due to too small clearance, installation error, sealing friction caused by excessive torque and so on. If there is no abnormality, power operation can be started.
2, large machinery can not be manually rotated, so after no-load start immediately cut off the power, mechanical idling, check whether there is vibration, noise, rotating parts are in contact, and so on, confirm no abnormal, enter the power operation
3, power operation, starting from no-load low speed, slowly improve to the specified conditions of rated operation. The check items in the test run are whether there is abnormal sound, bearing temperature change, lubricant leakage or discoloration and so on. If abnormal is found, the operation should be stopped immediately, the machinery should be checked, and the bearing should be removed if necessary.
4. Bearing temperature can generally be inferred according to the external temperature of the bearing seat. However, it is more accurate to directly measure the temperature of the bearing outer ring by using the oil hole. The bearing temperature gradually rises from the start of operation, and the temperature is usually stable after 1 to 2 hours. If the bearing is improperly installed, the temperature will rise sharply and abnormal high temperature will occur. The reasons such as excessive lubricants, bearing clearance is too small, poor installation, sealing device friction is too large. In the case of high speed rotation, the wrong choice of bearing structure and lubrication mode is also the reason.
Bearings are indispensable parts in mechanical equipment. Bearings have different forms in different mechanical equipment, and their functions and roles are different