YOCH Bearing

Contact fatigue failure refers to failure caused by alternating stress on the working surface of the bearing. Contact fatigue spalling occurs on the working surface of the bearing and is often accompanied by fatigue cracks. It first occurs from the maximum alternating shear stress below the contact surface, and then expands to the surface to form different spalling shapes, such as pitting or pitting spalling. Peeling off into small flakes is called shallow peeling. Due to the gradual expansion of the peeling surface, it often extends to deep layers, forming deep peeling. Deep spalling is a fatigue source of contact fatigue failure.

The fit between the inner hole of the bearing and the shaft adopts the base hole system, and the fit between the outer circle of the bearing and the bearing seat hole adopts the base shaft system. Generally, the shafts and bearing inner races of centrifugal pumps, centrifuges, reducers, electric motors and centrifugal compressors that work under normal load conditions use J5, js5, js6, k5, k6, m6, and the bearing seat hole and bearing The outer race uses j6 and J7 fit. The rotating seat ring (the inner seat ring of most bearings is a rotating seat ring, the outer seat ring is not a rotating seat ring, and a small number of bearings are the opposite), usually using an interference fit, which can prevent the seat ring from being in the shaft diameter under load. Rolling and sliding occur on the mating surface of the bearing housing bore.

Excitation force factors caused by changes in the number of loaded rolling elements When a radial load acts on a bearing, the number of rolling elements bearing the load during rotation will change slightly, resulting in a slight displacement of the bearing in the direction of the load. The resulting vibration is unavoidable, but it can be achieved by Axial preload is applied to all rolling elements to reduce vibration (not applicable to cylindrical roller bearings).

Grease has oxidation issues. When the grease is left (or run) for a period of time, it will have a lot of contact with oxygen. At the same time, the metal (the bearing itself) acts as a catalyst in this oxidation reaction. Therefore, when calculating the time interval for replenishing grease in bearings, the issue of oxidation must also be considered. During the operation of the bearing itself, the temperature (the bearing itself, or the environment) will change, which causes the base oil in the grease to continuously flow in and out of the thickener. At the same time, every time the base oil goes back, it may not go back completely. If this happens for a long time, the performance of the grease will change and it will no longer be able to lubricate, so lubrication needs to be reapplied. Grease with insufficient base oil may change color. Also, if the temperature is abnormal, the performance of the grease will also change greatly, so there will be discoloration. If the temperature is very high, it will carbonize. The color will become darker. During the operation of the bearing, impurities are mixed into the grease. This kind of impurity may be peeled off by the bearing itself, or it may be entered by the outside world. It may be solid or liquid, which will affect the properties of the grease.

The decisive role of chromium in stainless steel: There is only one element that determines the properties of stainless steel, which is chromium. Each stainless steel contains a certain amount of chromium. To date, there is no chromium-free stainless steel. The fundamental reason why chromium has become the main element that determines the performance of stainless steel is that adding chromium as an alloying element to steel promotes its internal contradictory movements to develop in a direction that is conducive to resisting corrosion damage.

Using advanced installation tools can avoid bearing damage caused by improper tools and operations during installation. For example, when installing bearings, workers used the tapping method of copper rods, which could easily cause uneven axial stress on the bearings, cause deformation of the cage, damage to the rolling elements, and increase in clearance. In addition, during the tapping process, the copper rods Copper powder flies into the bearing cage, which can easily cause bearing failure.

Bearings are an indispensable part of many mechanical parts. The performance of the bearings will directly affect the performance of the machinery. Therefore, many people will also pay attention to the performance of the bearings when purchasing mechanical equipment. Among them, the high and low speed operation of the bearings It plays a decisive role in the use of bearings.