In general, NTN integral eccentric bearings in the rolling bearings themselves do not produce noise.What is commonly perceived as "bearing noise" is in fact the sound effect of the bearing directly or indirectly vibrating with the surrounding structure.
This is why many times the noise problem can be considered as a vibration problem involving the entire NTN integral eccentric bearing application.When a radial load is loaded on a bearing, the number of rolling objects under its bearing load varies slightly during operation, that is: 2-3-2-3...This causes a shift in the direction of load.The resulting vibration is inevitable, but can be mitigated by axial preloading, which is applied to all rolling objects.
If the bearing ring is closely matched with the bearing housing or the transmission shaft, the bearing ring may be deformed by the appearance of adjacent parts.If deformation occurs, vibration may occur during operation.Therefore, it is important to machine the bearing and drive shafts to the required tolerances.
Partial damage A small number of bearing raceways and rolls may be damaged due to incorrect operation or installation.Rolling over the damaged NTN integral eccentric bearing component produces a specific vibration frequency during operation.Vibration frequency analysis can identify damaged bearing components.Vibration behavior in Many applications, the stiffness of the bearing is the same as that of the surrounding structure.Because of this feature, it is possible to reduce the vibration in an application by correctly selecting the bearings (including preload and clearance) and their configuration in the application.
First of all, if the structure design is reasonable and advanced, the bearing life will be longer.Bearing manufacturing generally through forging, heat treatment, turning, grinding and assembly, and other processing procedures.The rationality, advancement and stability of each processing technology will also affect the bearing life.The heat treatment and grinding process which affect the quality of the finished NTN integral eccentric bearing are often more directly related to the bearing failure.In recent years, the study of bearing working surface metamorphic layer shows that grinding technology is closely related to bearing surface quality.
The metallurgical quality of bearing materials used to be the main factor affecting the early failure of rolling bearings.With the improvement of metallurgical technology (such as vacuum degassing of bearing steel), the quality of raw materials has been improved.The proportion of raw material quality factor in bearing failure analysis has decreased obviously, but it is still one of the main influencing factors of bearing failure.Proper material selection is still a factor to be considered in bearing failure analysis.
The main task of NTN integral eccentric bearing failure analysis is to find out the main factors causing bearing failure according to a large number of background materials, analysis data and failure forms, so as to put forward targeted improvement measures, extend the service life of the bearing, and avoid bearing sudden early failure.
1) There is no obvious sound when the engine is running at idling speed, and "gurgling" noise (from inside the crankcase) occurs at medium and high speed.
2) The sound becomes more obvious immediately after releasing the throttle after urgent refueling.
3) There is no obvious change after the temperature rises.As the load increases, the sound increases.
4) The sound is slower and shorter than the sound of thrust angular contact ball bearing.
1) Excessive wear of bearing and journal, excessive radial clearance.
2) The fastening bolt of the bearing cover is loose.
3) Bearing alloy ablation or shedding.
4) Misalignment of journal.
5) The bearing rotates relative to the bearing seat.
1) When the engine speed is excessive from idle to medium speed, the sound is clear. As the speed increases, the sound becomes more prominent, which is abnormal noise of the bearing.
2) When a cylinder is tested for fire breaking, the sound weakens or disappears, and the cylinder bearing is louder.
3) No matter the speed and temperature are high or low, the bearing alloy will be ablated if the engine vibrates and the sound does not change during the fire break test.