Time：2020.01.08 Source：Roller Bearings Suppliers
The shaft parts of CNC machine tools, such as machine tool spindles, are generally assembled into thrust ball bearings and rotate at high speeds, which sometimes generate high heat. If this heat is not discharged promptly, it will cause angular contact ball bearings to overheat and cause the temperature of the corresponding parts of the CNC machine tool to rise, resulting in thermal expansion. When it is more serious, the spindle of the machine tool and the tailstock will not be the same height. This not only affects the precision of the CNC machine tool and the precision of production and processing but also burns out the rolling bearings. Therefore, we usually choose high-temperature bearings.
The rated power fatigue life refers to the total speed of each group of rolling bearings of the same model and specifications under high-speed operation under the same conditions, of which 90% of angular contact ball bearings do not exhibit cracking caused by rolling fatigue. When the speed is constant, people mostly use the total high-speed running time to express the rated power fatigue life.
When discussing the service life of thrust ball bearings, not only the fatigue life can be considered, but also the characteristics of rolling bearings should be considered, and several types of use limits should be considered. For example, grease lubricates the life of grease in rolling bearings. Noise service life, wear service life, etc. are different according to the applicable scope, and the use limit standards are different. Therefore, people will choose the experience limit firstly.
Therefore, only the statistical damage of angular contact ball bearings is investigated, and there is no way to find out the true cause of the damage. However, if you know the mechanical equipment of the thrust ball bearing, the prerequisites for use, the structure around the rolling bearing, and the specific situation before and after the accident, combined with the damage of the rolling bearing and several types of investigations, you can avoid similar accidents from recurring.
The judgment of whether an angular contact ball bearing is usable depends on the degree of damage to the rolling bearing, the mechanical performance, the importance, the premise of high-speed operation, and the period of the overhaul. If it has the following defects, it can no longer be used, and it must be replaced with a new thrust ball bearing. Any crack or gaps in the inner ring, outer ring, rolling body, or cage must be replaced.
Wear failure is one of the general failure modes of various types of rolling bearings. Generally, the wear failure can be divided into the most common abrasive wear and adhesive wear.
When taking oil-free bearings by hand, you should thoroughly wash off the sweat from your hands and apply high-quality mineral oil before carrying out the actual operation. Pay special attention to rust prevention in rainy and summery days. Under certain specific practical conditions, angular contact ball bearings can achieve a longer service life than traditional calculations, especially in light load situations.
The premise of this specific practical operation is that when the rolling surfaces (tracks and rolling elements) are reasonably separated by a grease film, and the pollution source is limited, the surface damage will be caused. In fact, under the premise of idealization, the service life of the permanent rolling bearing will not allow for strong punching, it is not allowed to hit the rolling bearing with a hammer immediately, and it is not permitted to use the rolling body to transmit pressure.
When the angular contact ball bearing rotates, the raceway surfaces of the inner and outer rings are in rolling contact with the rolling elements, so the running track is dark. The running track attached to the raceway surface does not belong to the occurrence of an abnormality, so that Find out the load prerequisite, so when disassembling the oil-free bearing, please pay special attention to and observe the running track of the raceway surface.