Several factors about radial clearance of double row deep groove ball bearings

Double row deep groove ball bearings radial clearance means the one ring is immovable while the other ring in the direction moves from one extreme location to another location perpendicular to the axis of double row deep groove ball bearings. Selection of bearing clearance is correct or not, has a great deal of influence to running accuracy, bearing life, mechanical friction, temperature, vibration and noise of bearings. For example, when spherical bearings radial clearance is small, the number of rolling elements bearing the load increases contact stress reduces, and stably operates, but frictional resistance will increase, and temperature also increases. Therefore, depending on the bearings’ using conditions, choose the most suitable clearance values, is of great significance. Selecting bearing clearance, must fully take into account the following key factors:

1, Tightness between double row deep groove ball bearings with shaft and housing bore will result in changes of bearing clearance value. Generally, bearing clearance values after installation will reduce;

2, During the operation of double row deep groove ball bearings, due to the different cooling conditions of the axis and the shell, it makes the temperature difference between inner and outer rings, which will lead to the clearance values reducing;

3, Due to different coefficients of expansion of the shaft and housing materials, clearance value will reduce or increase too.


Four specific ways to handle high temperature of deep groove ball bearings

When temperature of deep groove ball bearing rise, first determine whether the malfunction is wrong, if it rises indeed, it should be dealt with as follows:

(1). check cooling water pressure, flow and whether pipe systems are functioning correctly. If the water pressure low, may be filter clogged, you can shut down if cannot be processed in a timely manner, when it works, put into use again.

(2). check the speed governor oil pressure, low oil pressure may cause the cooling water of hydraulic valve close.

(3). check bearing abnormal noise, and inspect the swing of deep groove ball bearings for exceptions.

(4). take sample to observe whether oil color is changing, and test to see if bad. If confirmed, shut down replace new oil.

(5). check whether oil level is normal, if irregular, check that the oil drain valve is closed. If it is closed tightly, please supplement oil, if sealing pad is oil leakage, stop the machine and handle it.

When we use bearing, if its in very hot situation, then quickly stopped operating, and then find out its causes, and provide solution for processing in accordance with the above. But, due to different reasons for heat of deep groove ball bearings, there are different ways to resolve, so it should be treated and completed with the assistance of technical staff.

(A) filling grease method

So-called filling grease method is to fill in the right amount of grease to the bearing working surface regularly, which is one of the most commonly used way of lubricating grease.

(B) oil Cup method

Oil Cup method is to set the capping oil cup or pressure oily cup on bearing housings, rotating the capping and injecting the grease on with grease guns to apply grease injection. This is a commonly used way of lubricating grease.

(C) pressure for grease method

Pressure for grease method is to rely on the grease pump for grease. You should use good fluidity of lubricating grease.

(D) Centralized greasing method

Centralized greasing method is to supply grease for the deep groove ball bearings and other parts through the grease pump. Similarly, the grease used should be sacrifice good liquidity and excellent oxidation resistance and corrosion resistance.

Important factors in rupture of deep groove ball bearing cage

Important factors in rupture of deep groove ball bearing cage


Rupture of deep groove ball bearing cage belongs to the occasional and non-normal failure mode, we should analysis the causes of IKO bearing cage fracture following the five aspects below.

1,deep groove ball bearing is poor lubrication: IKO bearings is running in a lean State, forming adhesive wear, and deterioration of the working surface. Tear matter produced by adhesive wear is easy to enter into the cage, so that cage is in abnormal loads, has the potential to cause rupture of cage.

2,creep phenomena of deep groove ball bearings: creep mostly means sliding phenomenon of finger rings, in case of insufficient interference combined with surface, the loading point moves around due to sliding, direction ring relative to the circular shaft or housing location deviation.

3,cage of deep groove ball bearing material defects: cracks, large blocks of metal inclusions and shrinkage cavity defects, bubble and riveting short nails or nails, pad in half cage surface voids, serious damage may cause, these all may cause cage fracture.

4,deep groove ball bearing cage is abnormal load: not installed in certain place, tilt, and excessive interference,which easily caused tour gap reduced, increased friction and heat, surface softened, prematurely appeared exception peeling. As peeling extended, peeling foreign body entered into the frame hole, leading to the cage running block and producing attached load, increased cage wear. Such a deterioration in the loop, will may cause the cage fracture.

5,hard foreign body invasion: intrusion of foreign body exacerbates the cage wear and generate exception additional load, which can cause the cage fracture.

Selection of deep groove ball bearing grease on the importance of stability

1, rust-proof performance
Preferably, the anti-rust agent can be insoluble in water, with good adhesion, forming a layer of oil film on the steel surface.
2, mechanical stability
Insufficient mechanical stability of oil, during the operation, would make oil soap structure to mechanical disintegration, causing grease is destroyed, thus loss of lubrication.
3, oil seal
Oil seal is necessary barrier for the protection of deep groove ball bearings and lubricants from external contamination. TIMKEN bearings in operation, debris or moisture cannot penetrate TIMKEN bearings, to prevent damage to its case.
4, mixed greases
Do not mix incompatible greases. If two incompatible greases mixes, usually the consistency will become soft, lastly, it may cause TIMKEN bearing damage because greases loss.
5, classification of oils
Consistency of grease and lubricating ability is affected by temperature. In an operation at a temperature of TIMKEN bearings must select greases that have the correct grease consistency and good lubrication effect under the same temperature.

In the general case, fill volume of deep groove ball bearings grease , always exceeds the amount of directly involved in the practical needs of lubrication, cavity and bearing cover on and rolling the perimeter to form a contour. In this process, due to the extra grease resistance, bearing temperature rise quickly. Although most excess grease in the early running was out, and squeezing roller attachment grease is still likely to be between turning the rolling to the Raceway. The early stages, most of the grease is quickly (less than a minute) out of raceways, other grease with the bearing rolls loops. At the same time, the bearing temperature continued to rise, up until extra bearing grease is discharged,this may be called grease collection phase. According to TIMKEN quality and fill volume of grease in the bearings, this period can last a dozen minutes, or even hours.

After remaining bearing grease being discharged completely, leaving a small amount of grease on the contact surface in between rolling element and the Raceway, cage, and bearing goes into a normal stage. When temperature decreased gradually and reaches equilibrium. In other words, long-term lubrication, relies mainly on the film of grease to bear. In addition, the bearing in the long running process, outlines, as well as of the rolling element and the Raceway near to shrinking and ceding part of cage on the grease based oil, flow into the back between the Raceway and lubrication there is also a complementary role.

Bearing grease in the bearings of the different form the outline is not the same as the opening, be sure to form the outline draft, short journey times, long-term functioning of bearing temperature in low and stable, this is an ideal grease, particularly important for lubricating grease into drains.

Some so-called Eddy current type of grease is not, it is difficult to form contours, even forming contours tend to collapse, then rolled back over and over again the excess grease in the distance is strong mixing conditions, TIMKEN bearings, torque, temperature, and uneven, and may also generate noise, grease is also vulnerable to spoilage and wastage.

Deep groove ball bearings

Application of deep groove ball bearings are particularly broad scope. Therefore, there are many varieties and sizes of them. SKF standard series is composed of the following types:

Single row deep groove ball bearings

Single row deep groove ball bearings with filling slots

Stainless steel deep groove ball bearings

Double row deep groove ball bearings

Hybrid deep groove ball bearings

Deep groove ball bearings for high temperature applications

Cam rollers

1, single row deep groove ball bearings

Single row deep groove ball bearings are with particularly wide application. This type of bearing is designed to be simple for non-separable, suitable for high speed, even for very high speed and very durable in operation, almost no maintenance. Bearing Raceway of deep groove and the high tie between raceways and balls, deep groove ball bearings in addition to radial loads, can accommodate axial loads in both directions, even at high speeds as well.

Single row deep groove ball bearings are one of the most widely used bearings. Therefore, SKF has many varieties and sizes:

Open basic design bearings

Sealed bearings

ICOS oil sealed bearing units

With open ring groove of bearings, bearings with snap rings rings with or without opening.

Product family also includes bearings with a tapered bore.

2, deep groove ball bearings with filling slots

There is one filling slots on the ring and the outer ring of single row deep groove ball bearings with filling slots. Bearings with filling slots have a higher radial load capacity than bearings without filling slots, but their axial load carrying capacity is small. Moreover, this bearing should not be at the same standard bearings under the same high speed running. Depending on different applications, deep groove ball bearings with filling slots can be caged or without cage.

Small dimensions of these bearings are mainly used in automobile gear box, standard model identification, with cage.

Applications designed for heavy loads and low speed rotation of large bearings without cage.

3, stainless steel deep groove ball bearings

Stainless steel deep groove ball bearings can withstand moisture and corrosion caused by a number of other medias. This type of single row deep groove ball bearings the same as standard deep groove ball bearings, bearing raceway with a deep ditch, Compatibility between raceways and balls is extremely high. The bearings is without filling slots, in addition to radial loads, also subjected to bi-directional effects of axial loads, even at high speeds as well.

Operating characteristics of stainless steel deep groove ball bearings are the same as conventional steel deep groove ball bearings, but the load carrying capacity is low.

The bearings are provided with an open and sealed design, shaft sizes from 1 to 50 mm.

Model prefix w stainless steel bearings, for example, W626-2Z.

4, double row deep groove ball bearings

Double row deep groove ball bearings echoed with single row deep groove ball bearings in the design. These bearings have deep uninterrupted raceways and high tie between the balls and raceways. In addition to radial loads, they are also subjected to bi-directional effects of axial load.

Double row deep groove ball bearings are ideal for single bearings low bearing load of the bearing arrangement. Outer diameter and inner diameter of the same case, the double row bearings are slightly wider than single row bearings, but substantially higher than the load capacity of the 62 and 63 series single row bearings.

5, hybrid deep groove ball bearings

Standard ceramic hybrid bearings are mainly single row hybrid deep groove ball bearings. The reason is clear: deep groove ball bearings are the most widely used bearing type, particularly in the motor. Close fit between deep raceway grooves and roller, makes it able to withstand radial loads and axial loads in both directions.

inner ring diameter of Hybrid deep groove ball bearings varies from 5 to 110mm, and can meet the needs of most applications. Larger bearings can be customized.

6, deep groove ball bearings for high temperature applications

The bearings are without filling slots, in addition to radial loads, can accommodate moderate axial loads. This is characterized by radial internal clearance of the bearing and is equipped with a special cage. Large clearance is four times the C5 clearance, even in rapid cooling can prevent bites in the bearing. All surfaces of the bearing and the housing are manganese phosphate. It has antiseptic effect, and improve operational performance.

High temperature deep groove ball bearings are with a cylindrical bore, there are five different forms, as described follows.

VA201, for the most common applications

VA201 bearings without seal, with pressed steel cage. Using poly (alkyl-Asian) glycol/graphite mixture lubrication and can be used from-40 to + 250 ° c temperature range. At the time of high temperatures above + 200 ° c, suitable for dry lubrication.

2Z/VA201 with shield

2Z/VA201 has the same design as the VA201 bearings. There areshield on both sides to prevent solids from entering. In addition, the bearing load of poly (alkyl-Asian) glycol/graphite mixture amount is twice times the open VA201 bearings.

2Z/VA208-used in high temperature

Bearing 2Z/VA208-equipped with a segmented cage of graphite,-150 to + 350 ° c temperature of the environment. Graphite in the paragraphs to separate the bowls, at the same time provide the necessary lubrication. Bearings are equipped with two shield, axial guide cages and prevent solids from entering. When cage is rotated graphite powder released particles provide adequate lubrication for the bearing.

Another advantage of these bearings are good environmental performance. Even at the highest temperatures, and no dangerous gases or steam comes out.

-2Z/VA228, can be used for the highest requirements

2Z/VA228-bearing is SKF high-temperature applications in the “best”. Pure graphite with “ball” cage, the cage has opened up more areas of application for this high temperature bearings. Spherical cage is a unique invention of SKF, allows running at speed of up to 100r/min.

2Z/-VA216 for corrosive environments

When corrosive in application environments are especially strong, 2Z/VA216 design bearings are recommended. The bearings are filled with milky white all purpose grease this grease with a mixture of PTFE based fluorinated polyether oil that can be used from-40 to + 230 ° c temperatures. Bearing design and 2Z/VA201 are the same in other areas.

Under normal circumstances, the lubricant in the bearing filled free space and 25. On request, you can provide other fill level.

Deep groove ball bearing General by pair rings a group keep frame, a group just ball composed and a group keep frame constitute, deep groove ball bearing type code for 6. is production most general, application most broad of category bearing. deep groove ball bearing structure simple, using convenient, is production bulk maximum, and bear must of axis to load. Dang bearing of radial tour gap increased Shi, has corner contact ball bearing of features, can bear larger of axis to load.

Deep groove ball bearings are mainly used under purely radial load, can bear both radial and axial loads, when it is only when you take pure radial loads, contact angle is zero. When a deep groove ball bearing with larger radial internal clearance are, with angular contact bearings, can withstand greater axial loads. small coefficient of friction of deep groove ball bearings, speed limit is also very high, especially in axial load is a lot of fast-moving conditions, Deep groove ball bearing than thrust ball bearing more has superiority. and size same of other class bearing comparison, this class bearing friction factor small, limit speed high. in speed higher not used thrust ball bearing of situation Xia available the class bearing bear axis to load. deep groove ball bearing mounted in axis Shang yihou, can makes axis or shell of axis to displacement limit in bearing of axis to tour gap range within. While, dang shell hole and axis (or outer ring internal ring) relative has tilt Shi, (not over 8-16 according to tour gap determines) You can still work properly. However, that tilt, is bound to reduce the service life of the bearing.

Deep groove ball bearings compared with other types of bearings of the same size, minimal friction loss, higher speed limit, in the case of thrust ball bearing in high speed should not be used, such bearings are subjected to purely axial load. If improving the precision of their manufacturing, and bakelite, bronze, solid cage for hard materials such as aluminum, its speed increases.

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Compressive strength influences on the performance of IKO deep groove ball bearings

Compressive strength refers to the ability that do not crush or size does not change when bearing accomodate load.

How to ensure deep groove ball bearings used normal in the course, how to make IKO bearings be without injury and with longer life.Let me introduce some notes making bearing work well, which I wish to help you. Under normal circumstances, there are points as follows:

1, appropriate clearance of deep groove ball bearing, too large will impact, too small is poor lubrication that may be burnt.

2, improve quality of lubrication and control oil pressure, temperature and flow, strengthen the oil filter.

3, deep groove ball bearings and axle geometry and surface quality should be strictly guaranteed.

4, adopted in accordance with the demarcation of the fuel and lubricating oil.

5, control of engine temperature, in the under cooling or overheating cases is negative. In cold weather, preheating before starting of diesel engines and scroll hand crank that oil into the friction surface.

Cleanliness of bearing considerable influence on bearing life considerably. IKO bearings have special tests, with the result that their differences for a few times and even dozens of times to more than double. Higher cleanliness of bearing,the longer life.Therefore, improving the cleanliness of the lubricant can extend bearing life, also, with dirt particles of lubricating oil control under below 10 um, IKO bearings life can increase.

Influences on the lubrication properties

IKO bearings drop in cleanliness, not only affect the lubricant film formation, but also cause deterioration and aging of grease, thus affecting the grease lubrication performance.

Three criteria of SKF angular contact ball bearings failure

As we all know, sales and quality of SKF angular contact ball bearings is the highest in the world. With its professional production line, operations after strict inspection, sold around the world, it provides support for industrial development in the world. The quality of SKF angular contact ball bearings is the most important basis it earned market recognition,and so, which to determine the quality of SKF angular contact ball bearings?

First, bearings industrial design is reasonable and perfect to the world-class level, stronger quality guarantees its service life. SKF angular contact ball bearings have to be rigorously forged, heat treatment, machining, grinding together of the rigorous process, and every process will affect the service life of the bearing. The quality of finished products is directly related to the failure. With continuing advances in detection technology, grinding process of degenerating layer of SKF angular contact ball bearings is a close relationship of surface quality of them.

Second,metal used in the manufacture of SKF angular contact ball bearings, used to be one of the main factors to affect the bearing failure.Now,with metallurgy technology continues to progress, raw materials extraction has been good improved and the quality of the material also greatly enhance, the quality factors of raw materials in bearing failure has been significantly declined, but at this stage, the problem still exists.

Third,selection of bearing manufacturing is a factor must be considered. Usually SKF corner contact ball bearing failure of detection in the main is according to large of Beijing material, data analysis, failure environment, forging process, find SKF corner contact ball bearing failure of main factors, and solution off, convenient SKF corner contact ball bearing of constantly optimization, using life, and effectiveness of improve. Extending the service period of SKF angular contact ball bearings, avoiding unexpected early failure in bearing. Installation conditions is one of the leading factors in the use factors, SKF angular contact ball bearings are often caused by the installation is not the right package of SKF angular contact ball bearings between the various parts of the stress change, SKF angular contact ball bearings running in an abnormal state and early failure. According to the SKF angular contact ball bearings installed, used, maintained, maintenance of technical requirements, bearing the burden of the operation load, speed, temperature, vibration, noise monitoring and checks and lubrication, unusual now to find reasons to adjust, bring it back to normal.