Perspective of miniature bearing vibration differential equation

As can be seen from the solution of differential equation, the natural vibration caused by noise the salient features are: if turning speed hair change, the main frequency of the noise almost unchanged, the main frequency has nothing to do with speed, but the sound pressure level increases with the increase of rotational speed. Can improve the flatness of ring width, and increase the thickness of the ring and other methods to make inherent noise is improved. 2 caused by design, the processing of the noise is caused by a bearing design or manufacturing error. It mainly includes the following five kinds of noise. ( 1) Raceway noise it is well known that even with the most advanced processing technology and the most sophisticated machining equipment to race or rolling body surface, it is impossible to produce the absolute ideal circle. In the surface of raceway and rolling element always exist in any tiny shape error, the error on the macro performance for form error, waviness and roughness on the microcosmic. Vibration produced by wave grain degree and roughness includes a series of random pulse, when bearing rotation, the pulse will cause bearing raceway noise ', this constitutes the main component of bearing noise noise. Actually raceway sparked by the sound of sound energy is limited, such as in normal circumstances, the high quality bearing raceway of 25-6203 27分贝。 Raceway noise characteristics are as follows: (1) randomness of noise and vibration; (2) vibration frequency above 1 KHZ; (3) no matter how change speed, the main frequency noise almost unchanged while the sound pressure level increase with the increase of rotational speed; (4) when the radial clearance increases, the sound pressure level increased dramatically; (5) bearing stiffness increases, the total sound pressure level is reduced, even if the speed increases, the total sound pressure level increases; 6. The higher the lubricant viscosity, the lower the sound pressure level, but for grease lubrication, the viscosity, the shape of the soap fiber size may also affect the noise value. Strictly control the ring raceway and rolling body of roundness, waviness and roughness and machining precision of the rolling element, can show a lower rolling noise. ( 2) Roller rolling body noise is relative to the surface of the rolling roller rotation, sliding, friction and the impact of noise. The noise sound occurs mainly in the entry and exit roller load moment. When the bearings in bear radial load under the condition of operation, in the presence of load bearing inner area and the loading area. Because the bearing has certain radial clearance, so the load of roller and inner raceway is not contact, but due to the effect of centrifugal force may contact with the outer ring. Therefore, at low speed when the centrifugal force is less than the rolling body weight, rolling body will fall with race or cage collision and noise caused by the natural vibration of the shaft bearing.