What are the effects of different structures of IKO combined bearing on vibration and noise
1. Raceway sound
- Raceway noise is a kind of stable and continuous noise excited by the rolling body rolling in the raceway when the IKO bearing rotates. People pay attention to it only when its sound pressure level or tone is extremely high. In fact, the sound energy excited by the raceway sound is limited. For example, under normal conditions, the high-quality 6203 bearing raceway sound is 25 ~ 27db. This kind of noise is typical of single row deep groove ball bearings bearing radial load. It has the following characteristics: What are the effects of different structures of IKO combined bearing on vibration and noise
- A. noise and vibration are random; b. The vibration frequency is above 1kHz; c. No matter how the rotating speed changes, the main frequency of noise is almost unchanged, while the sound pressure level increases with the increase of rotating speed; d. When the radial clearance increases, the sound pressure level increases sharply; e. When the rigidity of the bearing pedestal increases, the lower the total sound pressure level is, and even if the speed increases, the total sound pressure level does not increase much; f. The higher the viscosity of lubricant, the lower the sound pressure level, but for grease lubrication, its viscosity and the shape and size of soap fiber can affect the noise value.What are the effects of different structures of IKO combined bearing on vibration and noise
- The sound generation source of raceway is caused by the natural vibration of ferrule after being loaded. The elastic contact between the ferrule and the rolling body constitutes a nonlinear vibration system. When the lubrication or machining accuracy is not high, the natural vibration related to this elastic feature will be excited, and when it is transmitted to the air, it will become noise. As we all know, even if the contemporary superb manufacturing technology is adopted to process the combined bearing parts, there will always be small geometric errors in varying degrees on the working surface, resulting in small fluctuations between the raceway and the rolling body and exciting the natural vibration of the vibration system. Although it is inevitable, high-precision machining of the working surface of parts, correct selection of bearings and accurate use of bearings can be adopted to reduce noise and vibration.
2. Falling body rolling sound
- In general, the noise mostly occurs in large combined bearings with low speed and radial load. When the bearing operates under radial load, the inner load area and non load area of IKO bearing. If the bearing has a certain radial clearance, the rolling element in the non load area does not contact the inner raceway, but may contact the outer ring due to the action of centrifugal force. Therefore, at low speed, when the centrifugal force is less than the self weight of the rolling element, the rolling element will fall and collide with the inner raceway or cage, and stimulate the natural vibration and noise of the bearing, And it has the following characteristics:
- A. It is easy to produce during grease lubrication and not easy to produce during oil lubrication. When using inferior grease, it is easier to produce. b. It often happens in winter. c. It is also easy to occur when only radial load is applied and radial clearance is large. d. Bearings of different sizes will also be produced in a certain range, and their speed ranges are also different. e. It may be continuous or intermittent. f.
- The forced vibration often excites the second-order and third-order bending natural vibration of the outer ring, resulting in the noise. This noise can be effectively reduced by using the preload method, the working radial clearance of the bearing after installation can be reduced, and the selection of good lubricant can also be improved. Some foreign enterprises adopt technical measures such as light rolling elements, such as ceramic rollers or hollow rollers, to prevent this noise.
- It is the sharp scream generated by the sliding friction between metals. Although the temperature rise of the combined bearing is not high at this time, it has little impact on the service life of IKO bearing and grease, and does not affect the rotation, the unpleasant sound is disturbing, especially for the large short cylindrical roller bearing bearing bearing bearing radial load. Its characteristics are as follows: A. It is easy to produce when the radial clearance of the bearing is large. b.
- It usually occurs in grease lubrication, and oil lubrication is rare. c. It decreases with the increase of bearing size, and often occurs in a certain speed range. d. It often occurs in winter. e. Its appearance is irregular and unpredictable, and is related to the amount and performance of grease filling, installation and operation conditions. This kind of noise can be prevented by reducing the radial clearance of the bearing and adopting the shallow outer ring raceway structure.
4. Cage sound
- This noise is caused by the free vibration of the cage and its impact with the rolling element or ferrule during the rotation of IKO bearing. It may appear in all kinds of bearings, but its sound pressure level is not too high and its frequency is low. Its features are: A. stamping cage and plastic cage can be produced. b. Both thin oil and grease lubrication will occur. c. It is easy to occur when the outer ring bears bending moment. d. It is easy to appear when the radial clearance is large.What are the effects of different structures of IKO combined bearing on vibration and noise
- Because the cage pocket clearance and the gap between cage and ferrule are inevitable in the finished bearing, it is very difficult to completely eliminate the cage sound, but it can be improved by reducing the assembly error and optimizing the reasonable clearance and cage displacement.What are the effects of different structures of IKO combined bearing on vibration and noise
- Another special sound of cage is the noise caused by the self-excited vibration of cage caused by the friction between cage and other IKO bearing parts. The stamping cage of the combined bearing is thin, the bending stiffness in the radial and axial planes is low, and the overall stability is poor. When the bearing rotates at high speed, it will produce self-excited vibration due to bending deformation and cause “buzzer”.What are the effects of different structures of IKO combined bearing on vibration and noise
- When the bearing is under radial load and the grease performance is poor, the noise of “click, click” will be heard at the beginning of operation, which is mainly due to the noise caused by the sudden acceleration of the rolling element and collision with the cage after leaving the load area. This kind of impact sound is inevitable, but will disappear after running for a period of time.
- The measures to prevent cage noise are as follows:
- a. In order to stabilize the rotation movement of the cage, the ring mode should be adopted as far as possible, and the surface should be fully lubricated. The combined bearing structure under high-speed working conditions should be improved, and the L-shaped cage of the roller should be changed into the Z-shaped cage with ring retaining edge.What are the effects of different structures of IKO combined bearing on vibration and noise
- b. When the bearing rotates at high speed, the vibration amplitude of the cage of the bearing with large pocket clearance is much larger than that of the cage with small pocket clearance, so the value of pocket clearance is particularly important.What are the effects of different structures of IKO combined bearing on vibration and noise
- c. Pay attention to reducing the radial clearance as much as possible.What are the effects of different structures of IKO combined bearing on vibration and noise
- d. Try to improve the manufacturing accuracy of the cage and improve the surface quality of the cage, which is conducive to reducing the noise caused by the collision or friction between the rolling element and the cage.
- e. Actively adopt advanced cleaning technology to effectively and thoroughly clean spare parts and products after assembly, so as to improve the cleanliness of bearings.What are the effects of different structures of IKO combined bearing on vibration and noise
5. The rolling element passes through vibration
- When the combined bearing operates under the radial load, only a few rolling elements in it bear the load. Due to the “spring” support formed by the elastic contact with the ferrule, the rolling element produces periodic vibration through the radial load action line, and the center of the rotating shaft will sag and move vertically or horizontally, causing noise at the same time. This kind of vibration is called rolling element through vibration, especially at low speed.What are the effects of different structures of IKO combined bearing on vibration and noise
- The amplitude is related to the type of combined bearing, radial load, radial clearance and the number of rolling elements. Generally, the amplitude is small. If the amplitude is large, it will cause harm. Therefore, it is often reduced by reducing the small diameter to the clearance or applying appropriate preload.What are the effects of different structures of IKO combined bearing on vibration and noise