Solution to heating damage and judgment of fag thrust ball bearing

The shaft parts of machine tools, especially the spindle, are generally assembled with rolling bearings or sliding bearings and rotate at a high speed, sometimes generating high heat. If this phenomenon is not eliminated in time, it will cause the fag bearing to overheat and cause the temperature of the corresponding parts of the machine tool to rise, resulting in thermal deformation. In serious cases, the height of the spindle and tailstock will be unequal, which will not only affect the accuracy and machining accuracy of the machine tool itself, but also burn out the bearing.Solution to heating damage and judgment of fag thrust ball bearing

Solution to heating damage and judgment of fag thrust ball bearing

• Generally, if the thrust ball bearing is used correctly, it can be used until the fatigue life is reached. However, there will be accidental and premature damage, which can not be resistant to use. This early damage, as opposed to fatigue life, is the quality service limit called failure or accident. Most of them are caused by careless installation, use and lubrication, foreign matters invading from the outside, and insufficient research on the thermal effects of shafts and shells.Solution to heating damage and judgment of fag thrust ball bearing
• As for the damage state of the bearing, such as the clamping damage of the ferrule and retaining edge of fag bearing, these reasons can be considered. These reasons also coincide with insufficient lubricant, unfitness, defects of oil supply and drainage structure, invasion of foreign matters, bearing installation error and excessive deflection of the shaft.
• Therefore, only investigating the bearing damage, it is difficult to know the real cause of the damage. However, if we know the use machinery and conditions of the bearing, the structure around the bearing, understand the situation before and after the accident, and investigate the damage state of the bearing and several causes, we can prevent the recurrence of similar accidents.Solution to heating damage and judgment of fag thrust ball bearing
• The judgment of whether the bearing is available is mainly determined by considering the damage degree, mechanical performance, importance, operating conditions and the period until the next maintenance of the thrust ball bearing. If there are the following defects, it can no longer be used, and the fag bearing must be replaced with a new one. There are cracks or notches on any one of the inner ring, outer ring, rolling element and cage.
• Any one of the ferrule and rolling element is broken.Solution to heating damage and judgment of fag thrust ball bearing
• There are significant card injuries on the rolling track surface, retaining edge and rolling body.
• Significant wear of cage or significant relaxation of rivets.
• There is rust and damage on the raceway surface and rolling element.Solution to heating damage and judgment of fag thrust ball bearing
• There are serious indentations and scratches on the raceway surface and rolling element.Solution to heating damage and judgment of fag thrust ball bearing
• There is obvious creep on the inner diameter surface of the inner ring or the outer diameter surface of the outer ring.
• Discoloration caused by heat is obvious.Solution to heating damage and judgment of fag thrust ball bearing
• The bearing, sealing ring or dust cover sealed with grease is obviously damaged.
• Fag bearing is the main vibration source that is difficult to control. Because the vibrating screen depends on a large excitation force to maintain the limit speed and friction coefficient of the working bearing, the radial force on the outer spherical bearing is large. During the working process of the vibrating screen, a large excitation force will cause the elastic vibration of the bearing system. If the lubrication is poor, there will be large friction, so that the bearing temperature rise is too high, the thermal expansion is too large, and the radial clearance is significantly reduced, which intensifies the friction and further improves the temperature rise.
• The locking methods of bearings are generally divided into two types:Solution to heating damage and judgment of fag thrust ball bearing

 Bearing attached with screws

• Just lock the fastening screw on the extension part of the inner ring to fix the bearing seat, and lock it with a hexagonal wrench. Please select a hex wrench of appropriate size.Solution to heating damage and judgment of fag thrust ball bearing

Bearing with locking sleeve

• The fair locking sleeve has a recess, which is fair to the vibration and temperature of the outer spherical bearing. The recess is fair to its inner hole, and there is also a part of the inner ring of the bearing seat. First position the fair sleeve on the inner ring, rotate the fair bearing sleeve quickly towards the rotation direction of the shaft until it is clamped, and lock the screw with a hexagonal wrench.Solution to heating damage and judgment of fag thrust ball bearing
• The vibration system composed of bearing and eccentric system can be regarded as a single degree of freedom system. Fag bearing driving shaft and driven shaft system have a certain resonance frequency. If a certain excitation frequency is close to the resonance frequency, resonance will occur. In addition, due to the centrifugal inertia force of eccentricity, bending vibration will occur, which is the material factor affecting the service life of bearing. If the speed is close to the critical value, bending resonance will occur.Solution to heating damage and judgment of fag thrust ball bearing
• From the fact that peeling, indentation, corrosion, crack, wear, etc. will be reflected in the vibration measurement of the bearing, the bearing vibration is very sensitive to the damage of the bearing. Therefore, the vibration of the bearing can be measured by using a special outer spherical bearing vibration meter (frequency analyzer, etc.), and the specific abnormal situation can not be inferred through the frequency division.
• Because the measured values are different due to the service conditions of the bearing or the installation position of the sensor, it is necessary to analyze and compare the measured values of each machine in advance to determine the judgment standard.Solution to heating damage and judgment of fag thrust ball bearing

• Even if the bearing has slight peeling and other damage, it will emit abnormal sound and irregular sound. Therefore, the sound detector can be used to distinguish. The sound detector is used to check the size and sound quality of the fag sound of the running bearing, which plays the role of prevention in advance.Solution to heating damage and judgment of fag thrust ball bearing
• No matter how high quality the outer spherical bearing is, if it is not used properly, it is difficult to obtain the expected high performance. Precautions for the use of fag bearings are as follows: Pay attention to keep the outer spherical bearing and its surroundings clean

• Even small dust will have a bad impact on the bearing. Therefore, keep the surrounding clean so that the dust will not invade the bearing.
• Use with care

• Strong impact on the bearing during use will produce scars and indentation, which will become the cause of the accident. In serious cases, it will crack and fracture, so we must pay attention to it.
• Use appropriate operating tools
• Appropriate tools must be used to avoid replacing existing tools.
• Pay attention to the corrosion of the bearing and replace it in time

• When operating the bearing, the sweat on the hand will become the cause of rust. Pay attention to operate with clean hands and try to wear gloves.
• After, in order to maintain the original performance of fag bearing in good condition for as long as possible, it is necessary to maintain and repair in order to prevent accidents, ensure the reliability of operation and improve productivity and economy.
• Maintain the operation standard of corresponding mechanical operation conditions and carry out it regularly. The contents include monitoring the operation status, replenishing or changing the lubricant, and regular disassembly inspection.
• As maintenance items in operation, there are rotating sound, vibration, temperature, lubricant state of outer spherical bearing, etc.