New technology and process equipment of Timken bearing grinding
New technology and process equipment of Timken bearing grinding
2022年5月9日
Use and fit of SKF Bearing
Use and fit of SKF Bearing
2022年5月9日

Fault analysis of SKF imported bearing of cement machinery

Local damage SKF imported bearing

  • Generally speaking, the rolling SKF Bearing itself does not produce noise. The commonly felt “SKF Bearing Noise” is actually the sound effect of SKF Bearing directly or indirectly vibrating with the surrounding structure. Fault analysis of SKF imported bearing of cement machinery
  • This is why many times noise problems can be considered as vibration problems involving the whole SKF Bearing application.Fault analysis of SKF imported bearing of cement machinery
  • Excitation caused by the change of the number of loaded rolling elements
  • When a radial load is loaded on a SKF Bearing, the number of rolling elements bearing the load will change slightly during operation, that is: 2-3-2-3 This causes an offset in the direction of the load. 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).Fault analysis of SKF imported bearing of cement machinery
  • Waviness of components
  • In the case of close fit between SKF Bearing Ring and SKF bearing seat or transmission shaft, SKF Bearing ring may be deformed by matching with the shape of adjacent components. If deformation occurs, vibration may occur during operation. Therefore, it is important to machine the SKF Bearing Pedestal and drive shaft to the required tolerances.Fault analysis of SKF imported bearing of cement machinery
  • Due to incorrect operation or installation, a small number of SKF bearing raceways and rolling elements may be damaged. During operation, rolling over damaged SKF Bearing components will produce specific vibration frequencies. Vibration frequency analysis can identify damaged SKF Bearing components.Fault analysis of SKF imported bearing of cement machinery
  • In many applications, SKF bearings have the same stiffness as the surrounding structure. Because of this feature, as long as the SKF Bearing (including preload and clearance) and its configuration in application are correctly selected, it is possible to reduce the vibration in application.Fault analysis of SKF imported bearing of cement machinery
  • There are three ways to reduce vibration:Fault analysis of SKF imported bearing of cement machinery
  • – remove critical excitation vibration from the application;Fault analysis of SKF imported bearing of cement machineryFault analysis of SKF imported bearing of cement machinery
  • – suppress the critical excitation vibration between the excitation part and the resonance part;
  • – change the stiffness of the structure to change the critical frequency.Fault analysis of SKF imported bearing of cement machinery

Vibration behavior in applications SKF imported bearing

  • Precautions for use
  • Rolling SKF bearings make precision parts, so it is required to be cautious when using them. High performance SKF bearings are used. If they are not used properly, they can not achieve the expected performance effect. Therefore, the following matters should be paid attention to when using SKF bearings:Fault analysis of SKF imported bearing of cement machinery
  • Keep SKF bearings and their surroundings clean. Even if the invisible smile dust enters the SKF Bearing, it will increase the wear, vibration and noise of the SKF Bearing.Fault analysis of SKF imported bearing of cement machinery
  • The use and installation shall be careful. It is not allowed to punch with force, directly knock the SKF Bearing with a hammer, and transfer pressure through the rolling element.Fault analysis of SKF imported bearing of cement machinery
  • Use proper and accurate installation tools, try to use special tools, and try to avoid using cloth and short fiber.
  • Prevent the corrosion of SKF bearings. When taking SKF bearings directly by hand, fully wash the sweat from your hands and apply high-quality mineral oil before operation. Pay special attention to rust prevention in rainy season and summer.Fault analysis of SKF imported bearing of cement machinery
  • Fit of SKF Bearing
  • The inner diameter and outer diameter of the rolling SKF Bearing are manufactured according to the standard tolerance. The tightness of the fit between the inner ring and the shaft, the outer ring and the seat hole of the SKF Bearing can only be realized by controlling the tolerance of the journal and the seat hole. The fit between SKF Bearing inner ring and shaft adopts base hole system, and the fit between SKF Bearing Outer Ring and seat hole adopts machine shaft system.Fault analysis of SKF imported bearing of cement machinery
  • To correctly select the fit, we must know the actual load conditions, working temperature and other requirements of SKF Bearing, which is actually very difficult. Therefore, in most cases, the matching is selected according to the use of fine grinding.Fault analysis of SKF imported bearing of cement machinery
  • Load size
  • The win-win amount between the ferrule and the shaft or shell depends on the size of the load. The heavier load adopts the larger win-win amount, and the lighter load adopts the smaller win-win amount
Fault analysis of SKF imported bearing of cement machinery

touch Fault analysis of SKF imported bearing of cement machinery

  • It is becoming more and more serious to check the condition of running machines and prepare a thorough inspection plan SKF Bearing is the focus of attention, because it is an important rotating part in all machines Preventive maintenance is an important part of condition monitoring Early detection of SKF Bearing Damage to avoid equipment shutdown during unscheduled maintenance caused by SKF Bearing damage
  • However, not all of them are equipped with this advanced instrument In this case, the operator or maintenance engineer of the machine must be highly alert to the “fault signal” of SKF Bearing, such as noise, temperature and vibration “Listening”, “touching” and “observing” are three important factors The views provided below can be used as your reference
  • High temperature often indicates that SKF Bearing is in abnormal condition High temperatures are also harmful to lubricants in SKF bearings Sometimes SKF Bearing Overheating can be attributed to the lubricant of SKF Bearing If SKF Bearing operates for a long time at a temperature of more than 125 ℃, the service life of SKF Bearing will be reduced The causes of high temperature SKF Bearing include insufficient or excessive lubrication, magazine contained in lubricant, excessive load, SKF Bearing Damage, insufficient clearance, high temperature friction caused by oil seal, etc
  • Therefore, it is necessary to continuously monitor the temperature of SKF Bearing, whether it is measuring SKF Bearing itself or other important parts If the operating conditions remain unchanged, any temperature change may indicate that a fault has occurred
  • The SKF Bearing temperature can be measured regularly with the help of thermometer, which can accurately measure the SKF Bearing Temperature and display it in degrees Celsius
  • Important SKF Bearing means that when it is damaged, it will cause equipment shutdown. Therefore, this kind of SKF Bearing should be equipped with temperature detector
  • Under normal circumstances, SKF bearings will have a natural temperature rise after just lubrication or re lubrication and last for one or two days

observation Fault analysis of SKF imported bearing of cement machinery

  • If SKF Bearing is well lubricated and properly blocks sundries and moisture, it means that the oil seal should not be worn However, when opening the SKF Bearing housing, visually inspect the SKF Bearing and regularly inspect the oil seal Check the condition of the oil seals near the Fault analysis of SKF imported bearing of cement machinery
  • SKF Bearing to ensure that they are sufficient to prevent hot or corrosive liquid or gas from penetrating into the SKF Bearing along the axis The protective ring and labyrinth oil seal should be coated with grease to ensure their great protection If the oil seal is worn, replace it as soon as possible
  • Due to the large size and heavy weight of its components, and limited by various process conditions such as casting, forging, cutting and assembly, the working accuracy of the hydraulic press itself cannot be completely guaranteed by the machining itself, but must be adjusted in the assembly process to achieve its accuracy indicators.Fault analysis of SKF imported bearing of cement machinery
  • The adjustment is carried out according to the specific requirements of Koyo bearing accuracy detection, and the maintenance and stability of accuracy depend on the relevant pre tightening and anti loosening means and measures. Fault analysis of SKF imported bearing of cement machinery
  • The hydraulic press used in all walks of life has different requirements for its working accuracy due to its different uses, and different industry standards are also used in production and manufacturing. In the same industry, due to different products, the required accuracy can not be consistent. Fault analysis of SKF imported bearing of cement machinery
  • Therefore, in the same industry standard, it is divided into several levels according to different working conditions, corresponding to each accuracy index. During the production of the factory, the technical department shall prepare the inspection outline and commissioning outline according to the accuracy standard of the production press, and issue them to relevant departments as guiding documents.Fault analysis of SKF imported bearing of cement machineryFault analysis of SKF imported bearing of cement machinery
  •  which specify the detection methods and corresponding data of relevant items and parameters as the standards for installation, adjustment, inspection and acceptance.Fault analysis of SKF imported bearing of cement machinery
  • Generally, it includes precision items that can be achieved only after adjustment in the process of assembling Koyo bearings. For example, in the hydraulic press, the levelness of the worktable, the deviation of column distance, the flatness of the worktable and movable worktable, the perpendicularity of the column and its connected upper and lower beams, the parallelism between the worktables. Fault analysis of SKF imported bearing of cement machinery
  • The perpendicularity of the main oil cylinder and the worktable within the working stroke, the contact rate of the internal and external nut joint surface between the column and the upper and lower beams, etc. Fault analysis of SKF imported bearing of cement machinery
  • The process and results of Koyo bearing accuracy adjustment and testing can be passed only after being approved and signed by full-time personnel. The tools and tooling required in the process of detection and adjustment are designed by the corresponding professional process personnel during production and programmed into the production process according to the plan. Inspection outline and inspection adjustment operation are omitted.Fault analysis of SKF imported bearing of cement machinery

Whether the outer packaging is clear: SKF imported bearing

 

  • generally, the brands of the main factory have their own special designers to design the outer packaging, and arrange the factories with qualified production conditions for production. Therefore, the packaging is very clear from line to color block – unambiguous.Fault analysis of SKF imported bearing of cement machinery
  • Whether the steel seal words are clear: the SKF Bearing body will be printed with brand words, labels, etc. The font is very small, but most of the products produced by the original factory use steel printing technology, and they are pressed before overheating treatment. Fault analysis of SKF imported bearing of cement machinery
  • Therefore, although the font is small, it is concave – deep and very clear. The font of counterfeit products is not only fuzzy, but also floating on the surface due to the rough printing technology. Some of them can even be easily erased by hand.SKF imported bearing 
  • Whether there is any noise: hold the inner sleeve of SKF Bearing with your left hand, and turn the outer sleeve with your right hand to hear whether there is any noise. Fault analysis of SKF imported bearing of cement machinery
  • Due to the backward production conditions of most counterfeit products and the complete manual workshop operation, it is inevitable that impurities such as sand will be mixed in the production process and hidden in the SKF Bearing, so it will make a noise when rotating. SKF imported bearing 
  • This is a big difference from the factory brand that strictly implements production standards and operates with machines.SKF imported bearing 
  • Pay special attention to whether the surface of SKF Bearing is muddy. As the current domestic antirust technology is not particularly good, it is easy to leave thick oil stains when antirust the SKF Bearing body, which is sticky and thick when holding it in your hand. SKF imported bearing 
  • However, there is almost no trace of antirust oil on the SKF Bearing originally imported from abroad. However, a particularly careful expert said that the imported SKF Bearing smells like a smell. It must be under antirust oil, but it can’t be seen.SKF imported bearing 
  • Whether the chamfer is uniform: the so-called chamfer of SKF Bearing, that is, the junction of horizontal and vertical surfaces. Due to the limitation of production technology, the fake SKF Bearing is not handled satisfactorily at these corners.SKF imported bearing 

Show signs of cross helix SKF imported bearing

  • In the grinding process of IKO bearing, its working surface is ground by high-speed rotating grinding wheel. Therefore, if the equipment is not operated and adjusted according to the operation instructions during grinding, various defects will appear on the working surface of IKO bearing, which will affect the overall quality of IKO bearing. SKF imported bearing
  • During precision grinding of IKO bearing, due to high requirements for roughness, the grinding marks on the working surface can often be observed with the naked eye. The surface grinding marks mainly include the following types.Fault analysis of SKF imported bearing of cement machinery
  • The reason for this trace is mainly due to the poor flatness of the bus of the grinding wheel and the concave convex phenomenon. During grinding, the grinding wheel is only in partial contact with the workpiece. When the workpiece or grinding wheel moves back and forth for several times, the cross helix will reappear in the performance of the workpiece and can be observed by the naked eye. Fault analysis of SKF imported bearing of cement machinery
  • The pitch of these spiral lines is related to the speed of the worktable and the rotating speed of the worktable. At the same time, it is also related to the non parallelism of the axis line of the grinding wheel and the guide rail of the worktable. Before scraping and grinding, carefully check whether the journal is smooth and whether there are defects such as rust and bruise, and try to eliminate them first;SKF imported bearing
  •  Then, check the contact between the journal and the shaft. The inspection method is to apply a thin layer of display agent (such as red lead powder, red Qian oil, etc.) on the shaft diameter, then install the journal in the Koyo bearing, rotate it two or three times in the positive and negative directions by hand, take out the shaft, and check the distribution of coloring points on the Koyo bearing. If the distribution of coloring points is abnormal or does not move at all, start scraping and grinding.Fault analysis of SKF imported bearing of cement machinery
  • During scraping and grinding, the principle of first heavy and then light, scraping heavy and leaving light, scraping large and leaving small shall be adopted according to the situation. For the first few times, the hand can be heavier and scrape off more metal, so as to achieve better contact quickly. When the contact area reaches 50%, it should be scraped gently. SKF imported bearing
  • After each scraping, wipe the tile surface, apply the display agent on the journal for inspection, and then scrape and grind according to the contact condition until it meets the technical requirements. Indicator can be used for scraping and grinding inspection, but for precision Koyo bearings with high requirements for contact points, indicator cannot be used in the later stage of scraping and grinding. SKF imported bearing
  • Because the coloring point on the Koyo bearing is too large after coating the display agent, it is difficult to judge the actual contact situation. Fault analysis of SKF imported bearing of cement machinery
  • At this time, the journal can be wiped clean, directly put in the Koyo bearing for verification, and then take out the shaft. It can be seen that the bright spot on the Koyo bearing is the contact point. Then scrape and grind the bright spot until it meets the technical requirements.SKF imported bearing
  • During scraping and grinding, not only the contact point shall meet the technical requirements, but also the side clearance and contact angle shall meet the technical requirements. SKF imported bearing
  • Generally, the contact point shall be studied first, and the contact angle shall be taken into account at the same time, and then the side clearance shall be scraped. There should be no obvious mark on the surface of the bearing when wiping the non-contact part with the finger, but there should be no obvious mark on the surface of the bearing.Fault analysis of SKF imported bearing of cement machinery
  • Principle requirements for inner packaging method of NTN bearing:Fault analysis of SKF imported bearing of cement machinery
  •  Micro NTN bearing: every 10 ~ 15 sets of NTN bearings are put into a plastic cylinder, and every 5 ~ 10 plastic cylinders are put into a carton (or bag or roll). ② Medium and small NTN bearings: multiple sets of NTN bearings are wrapped with polyethylene film inside and kraft paper or polyethylene composite paper outside; Install multiple sets of NTN bearings into a plastic cylinder (box); A single set of NTN bearings shall be packed in polyethylene film bags, folded or sealed, and then loaded into a carton.
  •   Large NTN bearings:
  • It is packed in a single set with polyethylene film or polyethylene composite paper, and then put into a carton; Use a polyethylene film bag, pack it in a single set, fold the bag mouth, and then put it into a carton; Put a single set into a special plastic box; A single set of three-layer wrapping packaging: polyethylene film tape or composite paper tape for the inner layer, fastening tape for the middle layer and waterproof permeable plastic tape for the outer layer.
  •  Extra large NTN bearing:
  • Single set of three-layer wrapping packaging (ditto); Single four layer wrapping packaging: after the above three layers of wrapping packaging, the outer layer is wrapped with a layer of linen tape.
  • For separable tapered roller NTN bearings with outer diameter ≥ 150mm, polyethylene film shall be padded before the inner and outer components, or the inner and outer components shall be packaged separately. For interchangeable cylindrical roller NTN bearings with outer diameter ≥ 150mm, because the complete package is easy to be damaged, the internal and external components can generally be packaged separately.
  • The general materials and requirements for the outer packaging of NTN bearings are as follows:
  •   Double corrugated boxes, with the total weight (gross weight) of each box not exceeding 25kg, bound with plastic packing belts outside the box; ② Nail board box (wooden box), the total weight of each box shall not exceed 30kg, and the outside of the box shall be bound with bluing steel belt; ③ Calcium plastic corrugated boxes, each with a total weight of no more than 25kg, are bound with plastic packing belts.
  • When NTN bearing products with inner packaging are put into the box, plastic bags or plastic films shall be padded in the box first; If there is a gap in the box, it needs to be filled with corrugated paper blocks, paper scraps and other dry substances.
  • Fault analysis of SKF imported bearing of cement machinery