Maintenance and judgment of preventing bearing heat treatment deformation
Maintenance and judgment of preventing bearing heat treatment deformation
2022年5月15日
Selection standard of fag imported machine tool spindle bearing
Selection standard of fag imported machine tool spindle bearing
2022年5月15日

Solution to the noise of raceway at the limit speed of bearing

What effect doeslimit speed of bearing?

  • In terms of its function, the bearing should be support, that is, it is literally used to support the bearing, but this is only part of its function. The essence of support is to be able to bear radial load. It can also be understood that it is used to fix the shaft. 
  • It is to fix the shaft so that it can only rotate and control its axial and radial movement. The consequence of motor without bearing is that it can’t work at all. Because the shaft may move in any direction, and the motor requires that the shaft can only rotate. 
  • Theoretically speaking, it is impossible to realize the function of transmission. Moreover, the bearing will also affect the transmission. In order to reduce this impact, good lubrication must be achieved on the bearing of high-speed shaft. Some bearings already have lubrication, which is called pre lubricated bearing, while most bearings must have lubricating oil. When running at high speed, friction will not only increase energy consumption, but also easily damage the bearing.
  • Whether it is a rolling bearing or a sliding bearing, when the shaft rotates, the rotating part and the stationary part cannot be in direct contact, otherwise it will be damaged due to friction. In order to prevent friction between dynamic and static parts, lubricant must be added. The effect of lubricant on bearing is mainly manifested in three aspects: lubrication, cooling and cleaning.
  • Bearings can be divided into many kinds, rolling bearings, radial bearings, ball bearings, thrust bearings and so on. In terms of its function, it should be support, that is, it is literally used to support the bearing, but this is only a part of its function. The essence of support is to be able to bear radial load. It can also be understood that it is used to fix the shaft. It is to fix the shaft so that it can only rotate and control its axial and radial movement.
  • What is the function of clutch release bearing?
  • Clutch release bearing is a kind of thrust bearing (commonly known as clutch spring disk). Its function is to move the pressing plate or driving plate bearing the spring thrust to the clutch housing when stepping down the clutch pedal, that is, when stepping down the clutch pedal, tilt the release lever to overcome the spring thrust of the pressing plate, so as to complete the separation of the clutch.
  • The release lever of the clutch rotates with the pressing plate, while the operating mechanism linked with the clutch pedal cannot rotate. In order to adapt to the different motion conditions between the two, thrust bearings are used to reduce friction and wear.
  • If the release bearing loses its sliding function due to lack of oil, it will not only produce abnormal noise, but also aggravate the stress point of the release rod, and the effective range of the clutch pedal starting pressing plate will be smaller and smaller. When the clutch plate is not completely separated from the pressure plate, the shift will produce abnormal noise.
  •  The wear of the release rod will cause uneven or incomplete start of the pressure plate, and the drive and driven are involved with each other, resulting in failure to shift. Rolling bearings can be divided into two categories according to the types of rolling elements: (1) ball bearings (ball bearings), whose rolling elements are balls; (2) Roller bearing (roller bearing), whose rolling element is cylindrical.
  • Rolling bearings can be divided into the following categories according to the load action direction they can bear:
  • Radial bearing can only bear radial load (such as radial short cylindrical roller bearing), or it can bear small axial load (such as radial ball bearing) while bearing radial load.
  • The radial thrust bearing can bear the combined radial and axial load, and may be dominated by radial load or axial load.
  • Thrust radial bearing can bear axial load, but it can also bear axial load and small radial load at the same time.
  • Thrust bearing can only bear axial load. 
  • The oil bath of the bearing is smooth. The oil bath is a common smooth way in the bearing, which is suitable for the smooth of low and medium speed bearings. Partially immerse the bearing in the groove, and the smooth oil is brought up by the rotating turbocharged bearing parts, and then flows back to the oil groove. The oil level should be slightly lower than the center of the low dynamic projectile.
  • The oil dripping of the bearing is smooth. The oil dripping is smooth. It is suitable for the bearing components that need to supply smooth oil quantitatively. The oil dripping amount is appropriate to drop once every 3-8 seconds. Excessive oil will cause the bearing temperature to increase.
  • The circulating oil of the bearing is smooth. The filtered oil is delivered to the bearing parts by the oil pump. The smooth oil after passing through the bearing is filtered and cooled before use. Since the circulating oil can take away certain heat and cool the bearing, this method is applied to turbocharged bearing components with high speed.
  • The spray of the bearing is smooth. The dry shrinking air is mixed with the smooth oil through the spray to cause oil mist. In the radial bearing, the air flow can effectively cool the bearing and avoid the invasion of impurities. This method is suitable for the smoothing of high-speed and low-temperature turbocharged bearing components.
  • The radiation of the bearing is smooth. Use the oil pump to shoot the low-pressure oil into the bearing through the nozzle, and the oil injected into the bearing flows into the oil groove through the other end of the bearing. When the bearing rotates at a high speed, the moving bullet body and the maintenance frame also cause air flow around at a fairly high rotation speed.
  •  It is difficult to send the smooth oil to the turbocharged bearing in an individual smooth way. At this time, the smooth oil must be sprayed into the bearing in the way of low-pressure radiation, and the position of the nozzle should be placed between the inner ring and the center of the maintenance frame.

 

  • When processing sleeve parts, pull the oil groove in the sleeve hole as much as possible. Because it is very difficult to refuel some parts of the harvester, butter and heavy oil can be used where it is difficult to refuel, except nylon sleeve. Where nylon sleeve is used, cast iron, copper and aluminum shall not be used instead, because the nylon sleeve bears certain impact and does not deform.Solution to the noise of raceway at the limit speed of bearing
  • The key and keyway on the pulley and shaft shall be repaired in advance, and the size of the key shall not be increased, otherwise the strength of the shaft will be affected. Solution to the noise of raceway at the limit speed of bearing
  • The keyway on the shaft can be repaired and welded with electric welding filler, and a key groove can be milled in the opposite direction of the old key. The keyway on the pulley can be inlaid (transition fit). After inlaying, use countersunk screws to tap and tighten the key in the socket seam.Solution to the noise of raceway at the limit speed of bearing
  • For the maintenance of the hydraulic part of the harvester, remove the distributor and flow reducing valve, and use the air pump to flush the pressure of each pipe fitting. The hydraulic oil shall be filtered and vented during secondary loading. The maintenance of hydraulic assembly is mainly the seal, and the seal shall be replaced after removal.Solution to the noise of raceway at the limit speed of bearing
Solution to the noise of raceway at the limit speed of bearing

Bearing damage limit speed of bearing

  • During the disassembly and inspection of rolling bearing, the fault and damage cause of bearing can be judged according to the damage of high-precision rotary table bearing. Generally speaking, the rolling bearing itself does not produce noise. 
  • The “bearing noise” usually felt is actually the sound effect of vibration between the bearing and the surrounding structure directly or indirectly. This is why many times noise problems can be regarded as vibration problems involving the whole bearing application.
  • Excitation caused by the change of the number of loaded rolling elements: when a radial load is loaded on a bearing, the number of loaded rolling elements will change slightly during operation, which causes the deviation of the load direction. 
  • The resulting vibration is inevitable, but can be reduced by axial preloading, which is applied to all rolling elements (not applicable to cylindrical roller bearings).
  • Local damage: a small number of bearing raceways and rolling elements may be damaged due to incorrect operation or installation. During operation, rolling over damaged bearing parts will produce specific vibration frequency. Vibration frequency analysis can identify damaged bearing components. This principle has been applied to condition monitoring equipment to detect bearing damage. To calculate the bearing frequency, refer to the calculation program “bearing frequency”.
  • Accuracy of relevant parts: when the bearing ring is closely matched with the bearing seat or transmission shaft, the bearing ring may be deformed by matching with the shape of adjacent parts. If deformation occurs, vibration may occur during operation.
  • Pollutants: if operating in a polluted environment, impurities may enter the bearing and be rolled by the rolling element. The vibration degree depends on the quantity, size and composition of the impurity particles being rolled. Although the typical frequency form will not be generated, a disturbing noise can be heard.
  • The causes of rolling bearing noise are complex. One is the wear of the mating surfaces of the inner and outer rings of the bearing. Due to this wear, the matching relationship between the bearing and the shell and between the bearing and the shaft is damaged, resulting in the axis deviation from the correct position and abnormal noise when the shaft moves at high speed. Solution to the noise of raceway at the limit speed of bearing
  • When the bearing is tired, the metal on its surface will peel off, which will also increase the radial clearance of the bearing and produce abnormal noise. In addition, insufficient bearing lubrication, dry friction and bearing breakage will produce abnormal sound. After the bearing is worn and loose, the cage is loose and damaged, which will also produce abnormal noise.Solution to the noise of raceway at the limit speed of bearing
  • In the daily use of bearings, we need to pay careful attention to their use. Let’s take a look at the nine matters we need to pay attention to.Solution to the noise of raceway at the limit speed of bearing
  • Riveted parts in the harvester, such as moving knife assembly, are generally made of cold extrusion. They should not be heated during riveting. If heated, the material strength will be reduced. After riveting, the forming punch shall be used to strengthen the firmness of the blade and cutter rod.Solution to the noise of raceway at the limit speed of bearing
  • Wearing parts, especially pin shaft, pressing plate, sleeve and sizing block, cannot be replaced by adding more butter in maintenance. For example, parts worn to the limit for a long time will shorten the service life of other machinery.Solution to the noise of raceway at the limit speed of bearing
  • For shaft repair without balancing machine, when balancing is required for repairing various shafts, a thrust bearing can be installed at one end of the shaft and clamped on the three claws of the lathe, and the other end can be supported by the center. limit speed of bearing
  • If the lathe is short, the SKF Bearing installed on the shaft at the other end can be clamped by the center frame to correct the balance. However, when balancing the weight, tighten it with screws and try not to balance the weight by electric welding.
  • In the maintenance, due to the variety of bearing materials and models, it is difficult to purchase, so it can be processed with waste shafts. At present, most shafts in China are mainly made of 45# carbon steel. IF quenching and tempering are required, in case of poor conditions, oxygen and earth furnace can be used to heat the required parts to red and black and place them in salt water, depending on the demand.Solution to the noise of raceway at the limit speed of bearing

How to measure and install limit speed of bearing

  • Take a single set of angular contact ball bearings as an example;Solution to the noise of raceway at the limit speed of bearing
  • The measurement method of outer diameter and inner diameter is the same as that of single row deep groove ball bearing. The width of angular contact deep groove ball bearing is called assembly height;Solution to the noise of raceway at the limit speed of bearing
  • AC contact type: Based on the big end, the preload acts on the big end face of the outer ring, and the actual force is on the other side of the inner ring; On the contrary, taking the big end as the benchmark, the preload acts on the other end face of the inner ring, and the actual force is on the big end face of the outer ring.Solution to the noise of raceway at the limit speed of bearing
  • BM contact type: similar to the above situation.Solution to the noise of raceway at the limit speed of bearing
  • Characteristics and application of angular contact ball bearing:Solution to the noise of raceway at the limit speed of bearing
  • The ultimate speed of angular contact ball bearing is high, which can bear both radial load and axial load, and can also bear pure axial load. Its axial load capacity is determined by the contact angle and increases with the increase of contact angle.Solution to the noise of raceway at the limit speed of bearing
  • Single row angular contact ball bearings can only bear axial load in one direction. When bearing radial load, additional axial force will be caused, and the corresponding reverse load must be applied. Therefore, this kind of bearings are generally used in pairs. Solution to the noise of raceway at the limit speed of bearing
  • Double row angular contact ball bearing can bear large radial and axial two-way combined load and moment load dominated by radial load. It can limit the two-way axial displacement of shaft or shell, and the contact angle is 30 degrees.Solution to the noise of raceway at the limit speed of bearing
  • Angular contact ball bearings installed in pairs can withstand radial and axial combined loads dominated by radial loads, as well as pure radial loads. The series configuration can only bear the axial load in a single direction, while the other two configurations can bear the axial load in either direction. Solution to the noise of raceway at the limit speed of bearing
  • This type of bearing is generally selected and combined by the manufacturer and submitted to the user in pairs. After installation, there is preloading interference, and the ferrule and steel ball are in the axial preload state, which improves the stiffness and rotation accuracy of the whole group of bearings as a single support. Features of articulated bearing:Solution to the noise of raceway at the limit speed of bearing
  • The articulated bearing can bear large load. According to its different types and structures, it can bear radial load, axial load or combined load of radial and axial at the same time. Because the outer spherical surface of the inner ring is inlaid with composite materials, the bearing can produce self lubrication in operation. Solution to the noise of raceway at the limit speed of bearing
  • It is generally used for low-speed swing movement and low-speed rotation. It can also make inclined movement within a certain angle range. When the non concentricity between the supporting shaft and the shaft shell hole is large, it can still work normally.Solution to the noise of raceway at the limit speed of bearing
  • Application scope of articulated bearing 
  • Articulated bearings are widely used in engineering hydraulic cylinders, forging machine tools, engineering machinery, automation equipment, automotive shock absorbers, hydraulic machinery and other industries Introduction and classification of plain bearings plain bearings are spherical plain bearings. The basic type is composed of inner and outer rings with spherical sliding spherical contact surfaces. Solution to the noise of raceway at the limit speed of bearing
  • According to its structure and type, it can bear radial load, axial load, or combined load acting both radially and axially. Because the spherical sliding contact area of the joint bearing is large and the inclination angle is large, but also because most joint bearings adopt special process treatment methods, such as surface phosphating, Solution to the noise of raceway at the limit speed of bearing
  • galvanizing, chromium plating or outer sliding surface lining, pad inlay, spraying, etc. It has good anti-wear, self-lubricating ability and anti-corrosion ability even if it is installed with large self lubrication and self-aligning capacity. Bearings are used for a wide range of swinging, tilting and joint movements.Solution to the noise of raceway at the limit speed of bearing