Listen to the sound, you can determine the motor bearing problem

According to the following four kinds of sound discrimination, the problem of motor bearing can be judged: 1. The rolling track sound track sound is a kind of smooth and continuous because the rolling elements roll in the raceway when the three-phase asynchronous motor bearing rotates. Noise is only noticeable when its sound pressure level or tone is very large. In fact, the sound energy evoked by the rolling track sound is limited, as in the normal case, the quality of the 6203 bearing raceway sound is 25 ~ 27dB. This kind of noise is typical for a single-row deep groove ball bearing subjected to radial load. It has the following characteristics: 1 Noise and vibration are random; 2 The vibration frequency is above 1kHz; 3 No matter how the speed changes, the main noise frequency is almost constant. The sound pressure level increases with increasing rotational speed; 4 When the radial clearance increases, the sound pressure level increases sharply; 5 The rigidity of the bearing housing increases, the lower the total sound pressure level, Even if the rotational speed increases, the total sound pressure level Also increase little; 6 The higher the viscosity of the lubricant, the lower the sound pressure level, but for the grease lubrication, the viscosity, soap fiber shape and size can affect the noise value. The origin of the raceway sound is due to the natural vibration of the ferrule after being loaded. Due to the elastic contact between the ring and the rolling element, a nonlinear vibration system is formed. When the lubrication or machining accuracy is not high, the natural vibration associated with this elastic characteristic is excited, and when it is transmitted to the air, it becomes a noise. It is well-known that even when bearing components are machined using modern manufacturing techniques, their work shows that there will always be small geometrical errors of varying degrees, which will cause small fluctuations between the raceway and the rolling elements to excite the natural vibration of the vibration system. Although it is unavoidable, however, the working surface of the part can be machined with high precision, the correct selection of the bearing and the accurate use of the bearing make it possible to reduce the noise and vibration. 2. Falling Rolling Noise This noise generally occurs in large bearings that are subject to radial loads at low speeds. When the bearing is operated under radial load, the bearing is in the load zone and the non-load zone. If the bearing has a certain radial clearance, the rolling elements in the non-load zone do not contact the internal raceway, but may be affected by centrifugal force. Circle contact, for this reason, at low speed, when the centrifugal force is less than the weight of the rolling body, the rolling body will fall and collide with the inner raceway or cage and excite the natural vibration and noise of the bearing, and has the following characteristics: 1 easy to grease lubrication Produced, oil lubrication is not easy to produce. It is easier to produce when using inferior grease. 2 Winter often happens. 3 It is also easy to produce when the radial load is only applied and the radial clearance is large. 4 Bearings that are also produced in a specific range and have different sizes have different speed ranges. 5 It may be continuous or intermittent. 6 This forced vibration often excites the second-order and third-order bending natural vibrations of the outer ring, thereby emitting this noise. By adopting the preload method, the noise can be effectively reduced, the radial clearance of the bearing after installation can be reduced, and the selection of good lubricant can also be improved. Some foreign companies adopt light rolling elements such as ceramic rollers or hollow rollers and other technical measures. To prevent this kind of noise. 3. The squeaking sound It is the squealing sound of the metal between the sliding friction. Although the bearing temperature rise is not high at this time, it will not affect the bearing life and grease life, and it will not affect the rotation. People are uneasy, especially the large short cylindrical roller bearings that bear radial load often have this noise, which is characterized by: 1 The bearing is easy to produce when the radial clearance is large. 2 is usually found in grease lubrication and oil lubrication is rare. 3 decreases with increasing bearing size, and often occurs within a certain speed range. 4 often occurs in winter. 5 Its appearance is irregular, unpredictable, and related to the amount of fat and performance, installation and operating conditions. This noise can be prevented by reducing the bearing radial clearance and using the shallow outer raceway structure. 4. Holder sound This noise is emitted when the cage is free to vibrate during rotation of the bearing and it collides with rolling elements or ferrules. It may appear in all types of bearings, but its sound pressure level is not too high and it is low frequency. Its characteristics are: 1 stamping cage and plastic cage can produce. 2 Whether it is thin oil or grease lubrication will appear. 3 Prone to occur when the outer ring is subjected to a bending moment. 4 It is easy to appear when the radial clearance is large. Since cage pocket clearances and cage and ferrule clearances inevitably exist in the finished bearing product, it is very difficult to eliminate the cage sound, but it can be improved by reducing the assembly error and optimizing the reasonable clearance and the cage turbulence. Another kind of special sound of the cage is the buzzing sound that occurs due to the self-excited vibration of the cage caused by the friction between the cage and the guide surfaces of other bearing components. Deep groove ball bearing punching cage is thin, the bending stiffness is low in the radial and axial plane, the overall stability is poor, the bearing will produce self-excited vibration due to bending deformation at high speed rotation, causing "buzzing sound" . When the bearing under the action of radial load and poor grease performance, early in the operation will hear the noise of “咔嚓, 咔嚓”. This is mainly due to the sudden acceleration of the rolling body and the cage after the rolling body leaves the load area. The noise from the collision, this installed sound is inevitable but disappears after a period of operation. Measures to prevent cage noise are as follows: 1 In order to stabilize the orbital motion of the cage, it should be possible to use the collar guide method and pay attention to the full lubrication of the guide surface, improve the structure of the tapered roller bearing under high speed conditions, and guide the roller. The L-shaped cage is replaced by a collar-guided Z-type cage. 2 When the bearing rotates at high speed, the vibration amplitude of the cage of the bearing with large pocket clearance is much larger than the vibration amplitude of the cage with small pocket clearance. Therefore, the value of pocket clearance is particularly important. 3 Pay attention to minimize radial clearance. 4 Try to improve the manufacturing precision of the maintenance price, improve the quality of the cage, and reduce the noise caused by collision or friction between the rolling elements and the cage. 5 Actively adopt advanced cleaning technology to effectively clean the parts and jointed products to improve the cleanliness of the bearings. ----- Responsible editor: Dalan Oil Pump Motor 02 - Procurement Consultant Copyright Office (Dalan Motor) Please indicate the source