Precautions for bearing installation

2020-09-01 14:29:18 嘉兴维恩机械有限公司 Viewd 675

According to news reports: Bearings are the most commonly used parts in mechanical assembly, and bearings are divided into two categories according to the friction properties at work-rolling bearings and sliding bearings. Today we will talk about rolling bearings.


Structure of rolling bearing


Rolling bearings include raceways (inner and outer rings), rolling elements (balls or rollers) and cages. The cages keep the rolling elements at a certain interval and fix them in the correct position for rolling motion.


1. Installation of bearing:


The installation of the bearing must be carried out under dry and clean environmental conditions. Before installation, carefully check the processing quality of the mating surface of the shaft and the housing, the end surface of the shoulder, the groove and the connecting surface. All mating connecting surfaces must be carefully cleaned and deburred, and the unprocessed surface of the casting must be cleaned of sand.


The bearing should be cleaned before installation, used after drying, and ensure good lubrication. The bearing is generally lubricated with grease or oil. When grease lubrication is used, greases with excellent performance such as no impurities, anti-oxidation, anti-rust and extreme pressure should be selected. The amount of grease filled is 30%-60% of the volume of the bearing and the bearing box, not too much. The sealed double-row tapered roller bearing and the water pump shaft bearing have been filled with grease and can be used directly by the user without cleaning.


When installing the bearing, an equal pressure must be applied to the circumference of the end face of the ring to press the ring in. It is not allowed to directly knock the end face of the bearing with a tool such as a head to avoid damage to the bearing. In the case of small interference, the end face of the bearing ring can be pressed with a sleeve at room temperature, and the sleeve can be beaten with a shovel to press in the ring evenly through the sleeve. If installed in large quantities, hydraulic presses can be used. When pressing, make sure that the end face of the outer ring and the end face of the housing shoulder, and the end face of the inner ring and the end face of the shaft shoulder are pressed tightly, and no gap is allowed.


When the interference is large, it can be installed by oil bath heating or induction heating bearing method. The heating temperature range is 80℃-100℃, and the highest cannot exceed 120℃. At the same time, use nuts or other appropriate methods to tighten the bearing to prevent the bearing from shrinking in the width direction after cooling and causing a gap between the ring and the shaft shoulder.


The clearance of single row tapered roller bearings should be adjusted at the end of installation. The clearance value should be specifically determined according to different operating conditions and the size of the matching interference. If necessary, it should be tested to determine. The double-row tapered roller bearing and the water pump shaft bearing have been adjusted to the clearance at the factory, so there is no need to adjust it during installation.


The bearing installation should be subjected to a rotation test. First, it is used for the rotating shaft or bearing box. If there is no abnormality, the power is used for no-load, low-speed operation, and then the rotation speed and load are gradually increased according to the operation situation, and noise, vibration and temperature rise are detected. If abnormalities are found, stop the operation and check. It can be delivered to use after normal operation test.


2. Disassembly of the bearing: When the bearing is to be used continuously after being removed, an appropriate disassembly tool should be used. When disassembling the ferrule with interference fit, only the pulling force can be applied to the ferrule, and it is never allowed to transmit the disassembly force through the rolling elements, otherwise the rolling elements and raceways will be crushed.


3. The use environment of the bearing: According to the location of use and the conditions of use and environmental conditions, the selection of specifications, size and accuracy, and matching with appropriate bearings are the prerequisites for ensuring the life and reliability of the bearing.


1. Part of use: Tapered roller bearings are suitable for bearing combined radial and axial loads based on radial loads. They are usually paired with two sets of bearings, mainly for the front and rear hubs, active bevel gears, and differentials of automobiles. Transmission parts such as gearboxes and reducers.


2. Allowable speed: In an environment with correct installation and good lubrication, it is allowed to be 0.3-0.5 times the limit speed of the bearing. Normally, 0.2 times the limit speed is the best.


3. Allowable tilt angle: Generally, tapered roller bearings are not allowed to tilt the shaft relative to the housing hole. If tilted, the maximum is not more than 2'.


4. Allowable temperature: Under normal load, the lubricant has high temperature resistance and sufficient lubrication, the general bearing is allowed to work at an ambient temperature of -30℃-150℃. Bearing Information Port according to news reports