2014年7月2日星期三

Influence of bearing structure on the vibration and noise(two).


4 holder of sound

Keep the free vibration of frame and the rolling body or ring phase impact will send this noise in the bearings rotate process. It may appear in all kinds of bearing, but itssound pressure level is not too high and the low frequency. Full complement cylindrical roller bearing Its characteristic is:

A. stamping cage and plastic holder can be generated

B. either oil or grease will appear.

C. when the outer ring bearing the bending moment is most likely to occur.

D. radial clearance large easily.

Because the cage pocket clearance and the holder and the ring gap is inevitable in bearing product to exist, self aligning bearing

thus completely eliminate cage sound is very difficult, but can reduce the assembly error, gap optimum and cage movement to improve.

Another cage special sound is due to the holder and the other bearing parts leading between the rubbing surfaces caused maintain self-excited vibration and noise frame.Stamping of deep groove ball bearing retainer is thin, curved in the radial and axial in-plane stiffness is low, the overall stability is poor, will the bearings rotate at high speed due to bending deformation caused by self-excited vibration, "beep".

When the bearing under a radial load and oil poor performance situation, at the beginning of operation "Kacha, Kacha hear noise", which is mainly due to the rolling body left in the load zone, noise suddenly accelerated and cage collision by rolling,the sound of impact can not be avoided but with running for a period of time will disappear.

To prevent the holder noise measures are as follows:

A. cage revolution motion stability, should as far as possible by the ring guide way and pay attention to guide the full lubrication, give the improvement of bearing structure of high speed conditions, the L type roller guide holder is changed to Z type ring ribguide holder.

B. bearings rotate at high speed, bearing pocket clearance of the cage vibration amplitude is much larger than the pocket hole cage vibration amplitude gap is small,so the pocket clearance value is very important.

C. should pay attention to reduce the radial clearance.

D. try to improve manufacturing precision frame maintain, improve the surface quality of the holder, helps to reduce body roll and keep the noise frame collision or friction.

E. actively adopt advanced cleaning technology, cleaning effective parts and the setof products, improving the cleanliness of bearing.

5 by rolling vibration

When the operation of the bearing under a radial load, its internal only a plurality ofrolling load, due to the ferrule elastic contact constitute the "spring" supporting therolling body in the radial load line generates periodic oscillation, and the shaft centerwill therefore vertically moving or moving horizontally, and causes noise. This kind of vibration is called rolling through the vibration, especially in low speed when the more obvious.

And the amplitude is related to bearing type, radial load, radial clearance and ballnumber. Usually the smaller amplitude, if the amplitude is large when the harm, this is often the minish preload appropriate axial clearance or to reduce.

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