In general, the eccentric bearing rolling bearing in itself does not produce noise. Often feel "bearing noise" is in fact bearing directly or indirectly with the surrounding structure of the sound effects of vibration.
This is why many times the noise problem can be regarded as relates to the vibration problem of the whole camshaft bearing applications. Vibration caused by loading a rolling body of quantity changes when a radial load on a bearing, the bearing load of the rolling element number may vary slightly in operation, namely: 2-3-2-3.... this caused offset in the direction of load. The resulting vibration is inevitable, but can be alleviated by axial loading, loading on all rolling body.
Components of the wave of the dense matching between the bearing ring and the bearing or shaft case, bearing ring may be with adjacent components shape matching and deformation. If there is deformation, in operation it may lead to vibration. Therefore, the bearing and shaft machined to the required tolerances is very important.
Local damage due to the operation or incorrect installation, small part of TIMKEN bearings raceways and rolling elements may be damaged. In the operation, rolled over the whole eccentric damaged bearing components will produce a specific vibration frequency. Vibration frequency analysis can identify the damaged bearing components. The vibration behavior of applications in many applications, the stiffness and the stiffness of the surrounding structure bearing the same. Because of this characteristic, as long as the correct choice of bearings (including preload and clearance) and in the application configuration, it is possible to reduce the vibration application.
First of all, reasonable structure design of both have advanced, there will be a longer bearing life. Manufacture of bearings are generally after forging, heat treatment, machining, grinding and assembling multi-channel processes. Rationality, advanced processing technology, the stability will also affect the TIMKEN bearing life. The effect of product overall quality of eccentric bearing heat treatment and machining processes, often has a more direct relationship with the bearing failure. In recent years, research on the working surface of the bearing metamorphic layer show, close to grinding and surface quality of bearing.
Metallurgical quality of TIMKEN bearing materials are the main factors that influence the early failure of rolling bearings once. With the development of Metallurgical Technology (such as vacuum degassing of steel bearing) progress, improved quality of raw materials. Raw materials quality factors has been a marked decline in the proportion of bearing failure analysis, but it is still one of the main influencing factors of bearing failure. Proper selection is still bearing failure analysis must be considered.
The main task of failure analysis whole camshaft bearing, is based on the analysis of data and the failure form of the large amount of background material,, find out the main factors causing bearing failure, so as to put forward the improvement measures, to extend the service period of bearings, avoid unexpected early bearing failure.
Phenomenon:
1) the engine idling no sound, and high-speed issued "giggle" sound (issued by the crankcase)
2) after acute gas throttle transient noise is more obvious.
3) temperature has no obvious change. When the load is increased, the sound increases.
4) sound more angular contact thrust ball bearing sound slow, short.
Reason.
1) bearing and shaft neck wear too much, the radial clearance is too large.
2) bearing cover fastening bolt loosening.
3) bearing alloy ablation or shedding.
4) axis neck circle loss.
5) the bearing and the bearing seat relative rotation.
Diagnosis.
1) the engine speed excessive idle speed to medium sound clear, with the speed increase, the noise is more prominent, as the TIMKEN bearing noise.
2) on a cylinder cutoff test, noise reduced or disappeared, as the cylinder bearing rings.
3) regardless of speed and temperature are audible, and the engine vibration, cutoff test sound does not change, then the bearing alloy ablation.



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