The shaft parts of the machine tool, especially the main shaft, are generally assembled with the thrust ball bearing and rotate at a high speed, sometimes generating high heat. If this phenomenon is not eliminated in time, it will cause the angular contact ball bearing to overheat and cause the temperature of the corresponding part of the machine tool to increase and cause thermal deformation. In severe cases, the spindle and the tailstock will not be equal, which not only affects the accuracy and machining accuracy of the machine tool itself. And will burn the bearing.
Rated fatigue life refers to the operation of a group of bearings of the same type under the same conditions, in which 90% of the angular contact ball bearings do not have the total number of revolutions caused by rolling fatigue. When the speed is constant, the total running time is used to indicate the rated fatigue life.
When studying the life of a thrust ball bearing, it is not only possible to consider the fatigue life, but also to consider the performance of the bearing and combine several use limits. For example, the grease life of grease lubricated bearings. Since the noise life, the wear life, and the like vary depending on the application, the use limit is different, and therefore, the experience limit is often selected in advance.
Therefore, it is difficult to know the true cause of the damage by investigating only the angular contact ball bearing damage. However, if you know the use of the thrust ball bearing machinery, the conditions of use, the structure around the bearing, and understand the situation before and after the accident, combined with the damage state of the bearing and several reasons, it can prevent similar accidents from happening again.
The judgment of whether the angular contact ball bearing is available is mainly determined by considering the degree of bearing damage, mechanical properties, importance, operating conditions, and the period of the next maintenance. If you have the following defects, you can no longer use them. You must replace the new thrust ball bearings. There is a crack or a gap in any of the inner ring, the outer ring, the rolling element, and the cage.
Wear failure is one of the common failure modes of various types of bearings. It is usually classified into the most common abrasive wear and adhesive wear according to the form of wear.
1. Oil film resistance diagnosis technology features: The same evaluation criteria can be used for different working conditions. It has a poor diagnostic effect on abnormalities such as surface peeling, indentation, and cracks.
Application range: Suitable for occasions where the rotating shaft is exposed.
2. Characteristics of vibration diagnosis technology: Vibration diagnosis technology is widely used; online monitoring can be realized; diagnosis is fast, and the diagnosis theory is mature.
Scope of application: Particularly suitable for fault monitoring of angular contact ball bearings in rotating machinery.
3. Characteristics of iron spectrum diagnosis technology: the machine does not need to be disintegrated; the investment is low, the effect is good; the early fatigue failure of the oil-free bearing can be found; the wear mechanism can be studied.
Scope of application: It is suitable for fault diagnosis of angular contact ball bearings lubricated with lubricating oil, which is difficult for bearings lubricated with grease.
4. Temperature diagnosis technology features: simple diagnosis; better judgment on bearing burns.
Applications: Simple routine diagnostics for bearings in machines.
5. Optical fiber monitoring and diagnosis technology features: high sensitivity of fiber displacement sensor; direct extraction of signals from oil-free bearing surface, improve signal-to-noise ratio; directly reflect manufacturing quality, surface wear, load, lubrication and clearance of angular contact ball bearings .
Application: Suitable for machines where the sensor can be mounted in a housing.
6. Acoustic emission diagnostic technology features: rapid and easy diagnosis; online monitoring.
Scope of application: New technologies developed in recent years have been used less in bearing condition monitoring.
When taking the oil-free bearing directly with your hand, wash off the sweat on your hands and apply high-quality mineral oil before handling. Pay special attention to rust prevention during the rainy season and summer. Under certain special operating conditions, angular contact ball bearings can achieve longer life than conventional calculations, especially at light loads. These special operating conditions are when the rolling surfaces (tracks and rolling elements) are effectively separated by a lubricating film and the surface damage caused by contaminants is limited. In fact, under ideal conditions, the so-called permanent bearing life is likely to not allow strong stamping, does not allow the hammer to directly hit the bearing, and does not allow pressure to be transmitted through the rolling elements.
When the angular contact ball bearing rotates, the raceway surface of the inner ring and the outer ring is in rolling contact with the rolling element, the running track is a dark surface, and the running track attached to the raceway surface is not an abnormality, thereby being known Load conditions, so when removing oil-free bearings, please pay close attention to and observe the running track of the raceway surface.
≤0.40%, while controlling w[P]≤0.010%. The aluminum-manganese Titanium warming agent is added to the scrap steel--the supplemental end point high carbon control is insufficient temperature; the tapping temperature is 1700°C, the carbon content is 0.34%, and the phosphorus content is 0.007%. ;? In the tapping process, high Cr alloy, Si-Mn alloy, carbon powder are used for alloying and carbonization in the package, and slag blocking operation is carried out, and the total oxygen in the molten steel is removed by bottom argon stirring; LF refining uses low alkalinity CaO-Al2O3 slag system, desulfurization rate of 50%-70%, reducing Al-type inclusions; consistent with deoxidation products, the interface tension between the two is small, easy to combine into a low melting point compound - - Strong absorption of Al2O3 inclusions and elimination of Class D inclusions containing CaO. At the same time blowing argon uniform composition, temperature; Blown argon weak agitation: According to the composition analysis of the reference sample, supplement the high chromium, high manganese and carbon powder to adjust the composition to meet the internal control requirements. When the temperature is higher than the temperature of the hanging bag 20-30 °C, the argon blowing is weakly stirred - the inclusion further Floating up?? Continuous casting
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