Structure and classification of KOYO imported bearings

Due to the different working conditions of various machines, KOYO bearings have various requirements in terms of load capacity, structure and performance. The KOYO imported bearings developed on the basis of plain bearings are based on rolling friction instead of sliding friction. Generally, two ferrules, a set of rolling elements and a cage are used for versatility, standardization and serialization. A very high degree of mechanical basics. To this end, KOYO bearings need to have a variety of structures. However, the most basic structure consists of the inner ring, the outer ring, the rolling elements and the cage.

The role of various parts in the bearing is:

For a radial bearing, the inner ring is usually tightly fitted to the shaft and operates with the shaft. The outer ring is usually in a transitional fit with the bearing housing or the mechanical housing bore to provide support. However, in some cases, there is also an outer ring running, the inner ring is fixed to support or the inner ring and the outer ring are simultaneously operated. For a thrust bearing, a shaft ring that fits tightly with the shaft and moves together, and a seat ring that is in a transitional fit with the bearing housing or the mechanical housing bore and serves as a support. The rolling elements (steel balls, rollers or needles) are normally arranged in the bearing between the two ferrules by means of a cage for rolling motion. The shape, size and number of the bearings directly affect the bearing capacity and performance of the bearing. In addition to the uniform separation of the rolling elements, the cage can also function to guide the rotation of the rolling elements and improve the lubrication performance inside the bearing.

1. According to KOYO imported bearing structure type classification

(1) Bearings are classified according to their load direction or nominal contact angle:

1) Radial bearing----Mainly used for bearing KOYO bearings with radial load, the nominal contact angle is from 0 to 45. According to the nominal contact angle, it is divided into: radial contact bearing----the radial bearing with the nominal contact angle of 0: the radial angular contact bearing---the radial bearing with the nominal contact angle greater than 0 to 45.

2) Thrust bearings----Mainly used for bearing KOYO bearings with axial load, the nominal contact angle is greater than 45 to 90. According to the nominal contact angle, it is divided into: axial contact bearing----the thrust bearing with the nominal contact angle of 90: thrust angular contact bearing----the thrust bearing with the nominal contact angle greater than 45 but less than 90.

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INA imported bearings damage regular maintenance measures

Rolling bearings, if there is no choice of mistakes can be used correctly, can be used for a long time before the life of INA bearings, in this case, the damage state is peeling.

On the other hand, there are accidental early damage, and early damage that cannot be used, as the cause of the early damage, there is insufficient consideration of the use of scare lubrication, and further foreign matter intrusion, error and shaft of INA imported bearing assembly The deflection is large, and the research on the shaft and the bearing housing is not enough. It can be said that these reasons overlap with each other.

Therefore, in order to fully understand the machine used in the bearing, the conditions of use, and the structure of the outer ring of the INA bearing, if the situation before and after the accident can be clarified, combined with the damage of the bearing and various reasons, it can be prevented. The same kind of accident happened again.

The equipment is inspected regularly, the operation inspection and the bearings removed during the replacement of the peripheral parts are inspected, and the second time is judged whether it can be used again or the use condition is better or worse. The bearings and appearance of the INA bearings that have been removed should be carefully investigated and recorded. In order to clarify and investigate the remaining amount of lubricant, the bearings should be cleaned well after sampling.

Next, check the condition of the raceway surface, the rolling surface and the mating surface, and the wear state of the cage, etc., for damage and abnormality.

Judging whether INA imported bearings can be used again, it is necessary to consider the degree of bearing damage, machine performance, importance, operating conditions, inspection cycle, etc. If the bearing is found to be damaged or abnormal, the contents of the injury section will be identified and the countermeasures will be developed. In addition, the inspection results, if there are the following defects, the bearings can no longer be used, need to replace the new INA bearings.

a. Cracks and fragments appear in any of the inner and outer rings, rolling elements, and cages.

b. Any one of the inner and outer rings and the rolling elements are peeled off.

c. The raceway surface, the ribs, and the rolling elements have significant jamming.

d. The cage is worn out or the rivets are loose.

e. The raceway surface, rolling elements are rusted and flawed.

f. There are significant indentations and marks on the rolling surface and the rolling elements.

g. There is creep on the inner diameter surface of the inner ring or the outer diameter of the outer ring.

h. Superheated and discolored.

i. Grease seal bearing seals and dust cover damage are serious.

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How to maintain and maintain SKF bearings

The purpose of lubrication of SKF bearings is to reduce internal friction and wear of the bearings and prevent burn-in. The lubrication effect is as follows:

1, reduce friction and wear

In the mutual contact portion of the ferrule, the rolling element and the retainer constituting the SKF bearing, metal contact is prevented, and friction and wear are reduced.

2, prolong fatigue life

The rolling fatigue life of SKF bearings is prolonged when the rolling contact surface is well lubricated during rotation. Conversely, if the oil viscosity is low and the thickness of the lubricating oil film is not good, it is shortened.

3, discharge friction heat, cooling

The circulation oil supply method or the like can be used to discharge heat generated by friction or heat from the outside to cool. Prevent the SKF bearing from overheating and prevent the lubricant from aging itself.

4, other

There is also the effect of preventing foreign matter from entering the inside of the bearing or preventing rust and corrosion.

Lubrication method: The lubrication method of SKF bearing is divided into grease lubrication and oil lubrication. In order to make the bearing function well, first, choose a lubrication method that suits the conditions of use and the purpose of use. Lubricity of oil lubrication predominates if only lubrication is considered. However, grease lubrication has the advantage of simplifying the structure around the SKF bearing, comparing the advantages and disadvantages of grease lubrication and oil lubrication.

In order for SKF bearings to be fully utilized and to maintain their proper performance for a long time, regular maintenance (regular inspection) must be performed. Through proper periodic inspections, early detection of failures and prevention of accidents are important to improve productivity and economy.

1, cleaning

When the SKF bearing is removed and inspected, the appearance record is first recorded by photography. In addition, confirm the amount of lubricant remaining and sample the lubricant before cleaning the SKF bearing.

a. The cleaning of the bearing is carried out by rough washing and fine washing, and a metal mesh frame can be placed on the bottom of the used container.

b. When rough washing, remove the grease or adhesive with a brush or the like in the oil. At this time, if the SKF bearing is rotated in the oil, be careful that the rolling surface will be damaged by foreign matter or the like.

c. When fine washing, slowly rotate the SKF bearing in the oil, and it must be carried out carefully.

The cleaning agent generally used is a neutral non-aqueous diesel oil or kerosene, and a warm alkali liquid or the like is sometimes used as needed. Regardless of which cleaning agent is used, it is often filtered and kept clean. Immediately after cleaning, apply anti-rust oil or anti-rust grease to SKF bearings.

2, inspection and judgment

In order to judge whether the removed SKF bearing can be reused, it is important to check its dimensional accuracy, rotation accuracy, internal clearance, mating surface, raceway surface, cage and seal. Regarding the inspection results, it can be judged by the SKF bearing or the SKF bearing. The criteria for judgment vary depending on mechanical properties and importance, inspection period, and the like. SKF bearings must not be reused if they are damaged and must be replaced.

a, the fracture and defects of the bearing components.

b. Peeling of the rolling surface of the raceway surface.

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The latest method of routine maintenance and maintenance of FAG sliding bearings

First, the bearing maintenance technology problems:

Two major complications related to FAG bearing maintenance technology are: 1. When to change oil. 2. How much oil should be changed? If the oil change is too small, the sliding bearing will be scrapped in advance; if the oil is changed too much, the bearing will be in trouble or the power coil and the coil will be damaged for a long time.

Second, the maintenance technology of the bearing:

The way to determine when to lubricate and when to stop oiling is simple: monitor when developing a baseline, setting up an observation schedule, and filling the oil.

1. Develop a basic line

The bearing base line reflects the decibel strength under normal operating conditions, no visible errors, and sufficient lubrication.

Three ways to develop a baseline:

1), comparison method: If there are multiple bearings of the same type, these sliding bearings can be put together for comparison. Use the same test method or observe each bearing from the same angle. Analyze the decibel intensity and sound quality. If there is no essential difference (less than 8 decibels), we can set it to the base decibel strength of each bearing.

2) Set the basic line when adding lubricating oil: When adding lubricating oil, listen to the intensity of the sound, when the sound intensity drops and then rises. At this time, do not add too much oil, and set it as the basic line.

3) History: Observe the decibel strength of the FAG bearing, record it every day, and then compare the recorded results for 30 days. If the decibel intensity changes little or no (less than 8 decibels), we can set this as the baseline and use it for later comparisons.

2, set the observation timetable

Equipment criticality associated with total production, environmental results, and operational results is a major factor in selecting and setting up an evaluation mechanical system. It is very necessary to test once a month after the basic observation line is established. For high-decibel bearings that are to be lubricated, the frequency should be detected more frequently so that changes that may occur are observed. If a bearing is in a state of destruction, the lubricant can only temporarily cover up the error. However, the decibel intensity will rise quickly to show the existence of the error. In some cases, this phenomenon will appear in a few minutes, while others will take several days.

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Method for reducing NSK bearing noise and maintenance and maintenance

(1) Using a vibration absorbing or vibration isolating device

The simplest example is a radial ball NSK bearing that can withstand thrust at high speed instead of a thrust NSK bearing. It can be fitted with a plastic jacket filled with anti-rust lubricant on its outer ring, a thrust NSK bearing with a casing or a general thrust NSK. The bearing, if permitted, is fitted with the same plastic sleeve in its inner or outer circumference, but the control must not rub or interfere with adjacent parts during rotation. This method has a certain muffling effect.

The use of vibration absorption or vibration isolation devices to reduce NSK bearing noise or isolate NSK bearing noise can achieve good results, but this often costs a lot of money, sometimes the mechanism becomes larger, the heat dissipation conditions become worse, or it is easy to rust. To be fully considered, this law will only be used after the other measures have not been adopted to achieve low noise indicators.

An example is the use of a sound-absorbing sound enclosure to completely enclose or substantially block the noise-generating NSK bearing system. The inside of the noise reduction cover is made of glass fiber or polyurethane foam, and the inner surface is a steel plate with a thickness of 0.6-lmm. The surface is uniformly distributed with small through holes of φ1.2-1.5mm, and the total area of ​​the small holes accounts for the entire inner surface. 25% to 30% of the surface, and the outer surface is a steel plate having a thickness of 2 mm.

Another example is to add an intermediate sleeve between the NSK bearing and the seat hole to attenuate the vibration force transmitted by the rotating system to the NSK bearing seat, but this requires proper deployment, otherwise the opposite effect may occur.

Here glass fiber or foam is used to eliminate higher frequency noise, the inner surface with small holes is used to eliminate lower frequency noise, and the thick steel plate on the outer surface is used to isolate the noise from the outside.

(2) Method of changing the rotational speed of the corresponding part of the host

In order to reduce the noise of the oil pump system, the oil pump that was originally used at a motor speed of 1430r/min at a flow rate of 10L/min was changed to a motor with a speed of 710r/min and equipped with a larger pump to obtain the same flow rate. The noise of the NSK bearing of the oil pump NSK bearing and the oil pump motor is significantly reduced, but the space occupied by the whole set of institutions has been expanded and the cost has also increased.

The noise of rolling NSK bearings is not very sensitive to the load, but it is sensitive to the speed. When conditions permit, the method of reducing the speed and increasing the torque achieves the same purpose, but reduces the noise.

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Maintenance, inspection, and abnormal handling of SKF bearings and damage measures

Maintenance, overhaul, and abnormal handling of SKF bearings

In order to maintain the original performance of SKF bearings in a good condition for as long as possible, maintenance, overhaul, and accident prevention are required to ensure the reliability of operation and improve productivity and economy. Maintenance is best carried out on a regular basis in accordance with the operating standards for the mechanical operating conditions. The contents include monitoring of operating conditions, replenishment or replacement of lubricants, and inspections for periodic disassembly.

Damage and countermeasures of SKF bearings

In general, if the SKF bearing is used correctly, it can be used until the fatigue life is reached. However, there will be accidents that are prematurely damaged and cannot be used. This early damage, as opposed to fatigue life, limits the quality of what is known as a fault or accident. Many of them are caused by inadvertent installation, use, and lubrication, and foreign objects intruding from the outside are insufficiently studied for the thermal effects of the shaft and the outer casing.

Regarding the damage state of the SKF bearing, for example, the jam of the ferrule rim of the roller bearing, as a cause, the lubricant is insufficient, unsuitable, the defect of the oil supply structure, the foreign matter intrusion, the SKF bearing installation error, the shaft If the deflection is too large, there will be coincidences of these reasons.

Therefore, it is difficult to know the true cause of the damage by only investigating the SKF bearing damage. However, if you know the use of SKF bearings, the conditions of use, the structure around SKF bearings, and understand the situation before and after the accident, combined with the damage state of SKF bearings and several reasons, it can prevent similar accidents from happening again.

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What should I do if the SKF bearing is damaged?

Stripping

Damage state: When the SKF bearing is subjected to load rotation, the raceway surface or the rolling surface of the inner ring and the outer ring exhibits fish scale-like peeling due to rolling fatigue.

Reason: The load is too large. Poor installation (non-linear) torque load foreign matter intrusion, water ingress. Poor lubrication, improper lubricant, SKF bearing clearance is not appropriate. The accuracy of the SKF bearing housing is not good, and the deflection of the rigid uneven shaft of the SKF bearing housing is caused by large rust, erosion points, scratches and indentations (surface deformation phenomena).

Measures: Check the size of the load and the SKF bearing used in the re-inspection to improve the installation method to improve the sealing device and prevent rust during shutdown. Use a lubricant of appropriate viscosity to improve the lubrication method. Check the accuracy of the shaft and SKF bearing housing. Check the clearance.

Peeling

Damage state: It shows a dark surface with slight abrasion. There are many tiny cracks on the dark surface from the surface to 5-10m deep, and tiny shedding (small peeling) occurs in a wide range.

Cause: The lubricant is not suitable. Foreign matter enters the lubricant. Poor lubricant causes a rough surface. The surface finish of the paired rolling parts is not good.

Action: Select a lubricant to improve the seal to improve the surface finish of the paired rolling parts.

Card injury

Damage state: The so-called card injury is a surface damage caused by a combination of minute burns generated in a sliding surface flaw. Linear flaws in the circumferential direction of the slide surface and the rolling surface. The tangential flaw of the roller end face is close to the pinch of the collar surface of the roller end face.

Reason: Excessive load, excessive preload. Poor lubrication. Foreign body bites into it. The inclination of the outer ring of the inner ring and the deflection of the shaft. The accuracy of the shaft and SKF bearing housing is poor.

Action: Check the size of the load. Preload should be appropriate. Improve lubricants and lubrication methods. Check the accuracy of the shaft and SKF bearing housing.

Broken

Damage state: The so-called fracture refers to a small portion of the fracture due to the application of a musical impact or an excessive load to a portion of the rim or the roller angle of the raceway.

Reason: The installation was hit. The load is too large. Poor use, such as falling.

Action: Improve the installation method (hot pack, use the appropriate tool holder). Correct the load conditions. The SKF bearing is mounted in place to support the ribs.

Crack, crack

Damage state: The so-called crack refers to the crack damage caused by the race wheel or the rolling element. If it continues to be used, it will also include cracks that develop cracks.

Reason: Too much excess. Excessive load, impact load. Stripping has developed. Heat and fretting wear due to contact of the raceway wheel with the mounting member. The fever caused by creep. The cone angle of the cone shaft is poor. The cylindricity of the shaft is poor. The corner radius of the shaft step is larger than the SKF bearing chamfer, which causes interference with the SKF bearing chamfer.

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