Correct installation can prevent premature failure of bearings

Proper installation of bearings can prevent premature failure of bearings

1. Fatigue effect of bearing touch

The effect of touch fatigue refers to the effect of alternating stress on bearing operation. Touch fatigue detachment occurs in the name of bearing operation, often accompanied by fatigue cracks. It first occurs at the greater alternating shear stress below the touch name, and then expands to form different detachment shapes in the name, such as pitting or pitting detachment, and shallow detachment refers to small flakes after detachment. Due to the gradual expansion of the detachment surface, it often extends towards deeper layers, forming a deep detachment. Deep detachment is the source of fatigue that affects the effectiveness of touch fatigue.

2. Effect of bearing wear

Wear and tear effect refers to the effect of sliding conflicts between nominal metals resulting in continuous wear and tear during operation. A rolling bearing composed of two or more bearing structures simultaneously within a set of bearings. For example, needle and thrust cylindrical roller combination bearings, needle and thrust ball combination bearings, needle and angular contact ball combination bearings, etc. Consecutive wear and tear will cause gradual damage to the entire bearing, leading to loss of bearing scale accuracy and other related issues. Wear may affect changes in appearance, increase in cooperative gaps, and changes in nominal job descriptions, or affect lubricants or cause them to become infected to a certain level, resulting in a complete loss of lubrication function, resulting in the loss of bearing rotation accuracy and even inability to operate abnormally. Wear effectiveness is one of the common forms of effectiveness for various types of bearings, which can be divided into more common types of abrasive wear and adhesive wear according to the wear form.

Abrasive wear refers to the wear caused by the squeezing of foreign hard particles, hard foreign objects, or metal debris between bearing operations, and the movement of the contact surface, often forming furrow like scratches during bearing operations. Hard particles or foreign objects may come from inside the host or from other adjacent machines in the host system, and are fed into the bearings by lubricating media. Adhesive wear refers to the uneven stress on the conflicting surface caused by micro protrusions or foreign objects in the conflicting name. When the lubrication condition deteriorates severely, heat is generated due to partial conflicts, which can easily lead to partial deformation and micro welding of the conflicting surface. In severe cases, the nominal metal may partially melt, and the contact surface exerts force to tear some conflicting welding points from the substrate, increasing plastic deformation. This cycle of adhesion tearing adhesion constitutes adhesive wear, with slight adhesive wear referred to as scratch and severe adhesive wear referred to as bite.

3. Effect of bearing cracking

The main reasons for the effectiveness of bearing cracking are defects and overload. When the external load exceeds the strength limit of the data and causes complete machine cracking, it is called overload cracking. The important cause of overload is sudden malfunction of the host or improper installation. Defects such as microcracks, shrinkage holes, bubbles, large foreign objects, overheating arrangements, and partial burns in the entire bearing can also cause cracking at the defect site during impact overload or intense oscillation, which is called defect cracking. It should be pointed out that during the production process of bearings, the re inspection of raw materials, quality control of casting and heat treatment, and processing process control can be accurately analyzed through instruments to determine whether the above defects exist. In the future, it is still necessary to strengthen the control. But individually, most of the common bearing cracking effects are caused by overload.

The reasons for high bearing temperature include: the quality of lubricating oil does not meet the requirements or deteriorates, and the viscosity of lubricating oil is too high; Tight organizational installation (lack of gaps); Bearing installation is too tight; The bearing race rolls on the shaft or inside the shell; Excessive load; Cracking of the bearing holder or rolling element.

1) The roundness of the shaft and seat hole, as well as the verticality of the shoulder, should be determined according to the corresponding accuracy of the bearing. The bearing industry in China has developed rapidly with imported bearings. The types of bearings have increased from few to many, the production quality and technical level have increased from low to high, and the industry planning has grown from small to large. It has now formed a professional production system with completely complete product categories and reasonable production layout.

2) It is necessary to correctly plan the interference amount for the cooperation of the rotating ring and the suitable amount for the fixed ring. The amount of burning interference of the rotating ring should also be relatively small within the scope. As long as the thermal expansion effect at operating temperature and the centrifugal force effect at higher speeds are effectively guaranteed, it is not possible to form tight cooperative nominal creep or sliding. The fixed ring is selected with very small gaps or interferences based on the size of the working load and the bearing size. Excessive looseness or tightness is not conducive to adhering to the original correct shape.

3) If the bearing operates at high speed and the operating temperature is high, special attention should be paid to the cooperation of the rotating ring not to be too loose to prevent eccentric oscillation, and the cooperation of the fixed ring not to have gaps to prevent deformation of the ring under load and trigger oscillation.

Rolling bearings allow for slight operating noise during operation. Assuming that the noise is too loud or there is no abnormal noise or impact sound, it indicates that the bearing is faulty. The bearing industry in China has developed rapidly with imported bearings. The types of bearings have increased from few to many, the production quality and technical level have increased from low to high, and the industry planning has grown from small to large. It has now formed a professional production system with completely complete product categories and reasonable production layout.

The reasons for noise in rolling bearings are quite complex, one of which is nominal wear of the inner and outer rings of the bearings. Due to this type of wear and tear, the cooperative relationship between the bearing and the housing, as well as between the bearing and the shaft, has been damaged, resulting in the axis deviating from the correct orientation and causing abnormal noise when the shaft is moving at high speed. When the bearing is tired, its nominal metal falls off, which can also increase the radial gap of the bearing and cause abnormal noise.