SKF inaugurates new factory in China

SKF inaugurated a new factory in Jinan on September 24, together with CNHTC, the largest truck manufacturer in China. The factory will provide tapered roller bearings and SKF Split Truck Hub Units for the truck market, as well as serve the industrial markets and vehicle aftermarket.

SKF China factory, Jinan

How are ball bearings made?

Background

Ever since man began to need to move things, he has used round rollers to make the job easier. Probably the first rollers were sticks or logs, which were a big improvement over dragging things across the ground, but still pretty hard work. Egyptians used logs to roll their huge blocks of stone for the pyramids. Eventually, someone came up with the idea of securing the roller to whatever was being moved, and built the first "vehicle" with "wheels." However, these still had bearings made from materials rubbing on each other instead of rolling on each other. It wasn't until the late eighteenth century that the basic design for bearings was developed. In 1794, Welsh ironmaster Philip Vaughan patented a design for ball bearings to support the axle of a carriage. Development continued in the nineteenth and early twentieth centuries, spurred by the advancement of the bicycle and the automobile.

There are thousands of sizes, shapes, and kinds of rolling bearings; ball bearings, roller bearings, needle bearings, and tapered roller bearings are the major kinds. Sizes run from small enough to run miniature motors to huge bearings used to support rotating parts in hydroelectric power plants; these large bearings can be ten feet (3.04 meters) in diameter and require a crane to install. The most common sizes can easily be held in one hand and are used in things like electric motors.

This article will describe only ball bearings. In these bearings, the rolling part is a ball, which rolls between inner and outer rings called races. The balls are held by a cage, which keeps them evenly spaced around the races. In addition to these parts, there are a lot of optional parts for special bearings, like seals to keep oil or grease in and dirt out, or screws to hold a bearing in place. We won't worry here about these fancy extras.

Raw Materials

Almost all parts of all ball bearings are made of steel. Since the bearing has to stand up to a lot of stress, it needs to be made of very strong steel. The standard industry classification for the steel in these bearings is 52100, which means that it has one percent chromium and one percent carbon (called alloys when added to the basic steel). This steel can be made very hard and tough by heat treating. Where rusting might be a problem, bearings are made from 440C stainless steel.

The cage for the balls is traditionally made of thin steel, but some bearings now use molded plastic cages, because they cost less to make and cause less friction.

The Manufacturing Process

There are four major parts to a standard ball bearing: the outer race, the rolling balls, the inner race, and the cage.

Races

• 1 Both races are made in almost the same way. Since they are both rings of steel, the process starts with steel tubing of an appropriate size. Automatic machines similar to lathes use cutting tools to cut the basic shape of the race, leaving all of the dimensions slightly too large. The reason for leaving them too large is that the races must be heat treated before being finished, and the steel

Surprisingly, the rolling balls start out as thick steel wire. Then, in a cold heading process, the wire is cut into small pieces smashed between two steel dies. The result is a ball that looks like the planet Saturn, with a ring around its middle called "flash." usually warps during this process. They can be machined back to their finished size after heat treating.

• 2 The rough cut races are put into a heat treating furnace at about 1,550 degrees Fahrenheit (843 degrees Celsius) for up to several hours (depending on the size of the parts), then dipped into an oil bath to cool them and make them very hard. This hardening also makes them brittle, so the next step is to temper them. This is done by heating them in a second oven to about 300 degrees Fahrenheit (148.8 degrees Celsius), and then letting them cool in air. This whole heat treatment process makes parts which are both hard and tough.

 • 3 After the heat treatment process, the races are ready for finishing. However, the races are now too hard to cut with cutting tools, so the rest of the work must be done with grinding wheels. These are a lot like what you would find in any shop for sharpening drill bits and tools, except that several different kinds and shapes are needed to finish the races. Almost every place on the race is finished by grinding, which leaves a very smooth, accurate surface. The surfaces where the bearing fits into the machine must be very round, and the sides must be flat. The surface that the balls roll on is ground first, and then lapped. This means that a very fine abrasive slurry is used to polish the races for several hours to get almost a mirror finish. At this point, the races are finished, and ready to be put together with the balls.

Balls

• 4 The balls are a little more difficult to make, even though their shape is very simple. Surprisingly, the balls start out as thick wire. This wire is fed from a roll into a machine that cuts off a short piece, and then smashes both ends in toward the middle. This process is called cold heading. Its name comes from the fact that the wire is not

The bulge around the middle of the rolling balls is removed in a machining proess. The balls are placed in rough grooves between two cast iron discs. One disc rotates while the other one is stationary; the friction removes the flash. From here, the balls are heat treated, ground, and lapped, which leaves the balls with a very smooth finish.

heated before being smashed, and that the original use for the process was to put the heads on nails (which is still how that is done). At any rate, the balls now look like the planet Saturn, with a ring around the middle called "flash."

• 5 The first machining process removes this flash. The ball bearings are put between the faces of two cast iron disks, where they ride in grooves. The inside of the grooves are rough, which tears the flash off of the balls. One wheel rotates, while the other one stays still. The stationary wheel has holes through it so that the balls can be fed into and taken out of the grooves. A special conveyor feeds balls into one hole, the balls rattle around the groove, and then come out the other hole. They are then fed back into the conveyor for many trips through the wheel grooves, until they have been cut down to being fairly round, almost to the proper size, and the flash is completely gone. Once again, the balls are left oversize so that they can be ground to their finished size after heat treatment. The amount of steel left for finishing is not much; only about 8/1000 of an inch (.02 centimeter), which is about as thick as two sheets of paper.

• 6 The heat treatment process for the balls is similar to that used for the races, since the kind of steel is the same, and it is best to have all the parts wear at about the same rate. Like the races, the balls become hard and tough after heat treating and tempering. After heat treatment, the balls are put back into a machine that works the same way as the flash remover, except that the wheels are grinding wheels instead of cutting wheels. These wheels grind the balls down so that they are round and within a few ten thousandths of an inch of their finished size.

• 7 After this, the balls are moved to a lapping machine, which has cast iron wheels and uses the same abrasive lapping compound as is used on the races. Here, they will be lapped for 8-10 hours, depending on

The four parts of a finished ball bearing: inner race, outer race, cage, and ball. how precise a bearing they are being made for. Once again, the result is steel that is extremely smooth.

Cage

• 8 Steel cages are stamped out of fairly thin sheet metal, much like a cookie cutter, and then bent to their final shape in a die. A die is made up of two pieces of steel that fit together, with a hole the shape of the finished part carved inside. When the cage is put in between and the die is closed, the cage is bent to the shape of the hole inside. The die is then opened, and the finished part is taken out, ready to be assembled.

• 9 Plastic cages are usually made by a process called injection molding. In this process, a hollow metal mold is filled by squirting melted plastic into it, and letting it harden. The mold is opened up, and the finished cage is taken out, ready for assembly.

Assembly

• 10 Now that all of the parts are made, the bearing needs to be put together. First, the inner race is put inside the outer race, only off to one side as far as possible. This makes a space between them on the opposite side large enough to insert balls between them. The required number of balls is put in, then the races are moved so that they are both centered, and the balls distributed evenly around the bearing. At this point, the cage is installed to hold the balls apart from each other. Plastic cages are usually just snapped in, while steel cages usually have to be put in and riveted together. Now that the bearing is assembled, it is coated with a rust preventative and packaged for shipping.

Quality Control

Bearing making is a very precise business. Tests are run on samples of the steel coming to the factory to make sure that it has the right amounts of the alloy metals in it. Hardness and toughness tests are also done at several stages of the heat treating process. There are also many inspections along the way to make sure that sizes and shapes are correct. The surface of the balls and where they roll on the races must be exceptionally smooth. The balls can't be out of round more than 25 millionths of an inch, even for an inexpensive bearing. High-speed or precision bearings are allowed only five-millionths of an inch.

The Future

Ball bearings will be used for many years to come, because they are very simple and have become very inexpensive to manufacture. Some companies experimented with making balls in space on the space shuttle. In space, molten blobs of steel can be spit out into the air, and the zero gravity lets them float in the air. The blobs automatically make perfect spheres while they cool and harden. However, space travel is still expensive, so a lot of polishing can be done on the ground for the cost of one "space ball".

Other kinds of bearings are on the horizon, though. Bearings where the two objects never touch each other at all are efficient to run but difficult to make. One kind uses magnets that push away from each other and can be used to hold things apart. This is how the "mag-lev" (for magnetic levitation) trains are built. Another kind forces air into a space between two close-fitting surfaces, making them float apart from each other on a cushion of compressed air. However, both of these bearings are much more expensive to build and operate than the humble, trusted ball bearing.

Resource: http://www.madehow.com/Volume-1/Ball-Bearing.html#b#ixzz2Ar8VaLSH

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

When deep groove ball bearing' temperature 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

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 cretain 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 creat exception additional load, which can cause the cage fracture.

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.

Check more details at http://www.ziso.cn/ or more products at http://www.hisupplier.com/a-single-row-ball-bearing/.

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.

Check more details at http://www.ziso.cn/ or more products at http://www.hisupplier.com/a-single-row-ball-bearing/.

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.

Cleaning, maintenance and damage judgments for SKF deep groove ball bearings

1, bearing cleaning
When removing SKF deep groove ball bearings and repair, first record the bearing appearance,in order to confirm the residual amount of lubricant. After checking the lubricant used for sampling, wash bearings. Use ordinary gasoline, kerosene as a cleaning agent.

Bearing cleaning divided into rough cleaning and sperm washing. Respectively place on the bottom of the metal net in a container so that SKF deep groove ball bearings do not directly touch the dirt in container. When rough cleaning, if you rotate the bearing with dirt will damage bearing rolling surface, so you should notice. In cleaning crude oil, use the brush removing grease, adhesive, and then turn into sperm washing.

Sperm washing, is rotating side SKF deep groove ball bearings in cleaning oil while carefully cleaned. In addition, cleaning oil regularly to keep clean.

2, bearing maintenance and judgment
In order to determine if removed SKF deep groove ball bearings can be used, check after bearing washed clean. Carefully check the raceway surface, rolling surface, the status of the mating surfaces, cage wear, clearance increases and injury due to decline in accuracy, exception.

With separation bearing like SKF deep groove ball bearings, you can check outer ring raceway and rolling body respectively.

Larger bearings cannot be rotated with hands, note to check the rolling element and the Raceway, cage, flange surface appearance.

Whether the bearing can be used is depend on bearing damage, mechanical properties, and the operating conditions, and determined during the next maintenance. However, if have the following defects,SKF deep groove ball bearings can no longer be used, must be replaced:
(A) any cracks or gaps on inner ring, outer ring, rolling elements, cages;
(B) fracture on the rings or rolling elements;
(C) a significant wound on raceway surface, rib, rolling body;
(D) cages wear significantly, or rivets relaxation significantly;
(E) rust, wound on raceway surface or rolling body;
(F) serious creasing and marks on raceway surface or rolling element;
(G) clear the inner circle diameter or outer ring outside diameter surface creep;
(H) discoloration obviously due to thermal ;
(I) broken clearly of the seals or shields.

Single row ball bearings

Single row ball bearings have raceways in the inner and outer rings that are displaced with respect to each other in the direction of the bearing axis. This means that they are designed to accommodate combined loads, i.e. simultaneously acting radial and axial loads. The axial load carrying capacity of Single row ball bearings increases with increasing contact angle. The contact angle a is defined as the angle between the line joining the points of contact of the ball and the raceways in the radial plane, along which the load is transmitted from one raceway to another, and a line perpendicular to the bearing axis

It include the following types:
- single row angular contact ball bearings
- double row angular contact ball bearings
-four-point contact ball bearings

High speed angular contact ball bearings

Check more infomation http://www.hiana-bearings.com/single_row_ball_bearings.htm and for products at http://www.hisupplier.com/a-single-row-ball-bearing/

SKF single row angular contact ball bearings

SKF paired single row angular contact ball bearing have 72XX and 73XX two series and bearing accuracy is P6 level. They can form any group dubbed the back-to-back or face-to-face. Their suffix meaning:

B--40 °; 

E--high carrying capacity; 

CB/GA--clearance/preload

SKF has 3 clearance level:

CB--standard axial clearance, bearings installed;

CC--axial clearance less than CB;

CA--axial clearance less than CC

SKF also has 3 types of preload class:

GA--light preload;

GB--preload than GA class;

GC--preload is larger than GB level;

Cage type:

SKF offers two types of centrifugal pump cage bearings applied to petrochemical industry. Machined brass cage (m) and hammer-type steel cage (j). Using instead plastic cage bearing is strictly prohibited.

Here we elect suffix is BECBM angular contact ball bearings used in petrochemical industry of centrifugal pumps. Not just because it is less after staging the bearing internal clearance (CB) is a good control over rolling bearing with sliding and machined brass cage more sturdy than the blow pressed-steel cage design, with high working reliability. Because of this, many petrochemical companies are using the suffix BECBM bearings as they are standard.

Single and double row angular contact ball bearings

Angular contact ball bearings of 70,000 are composed of the outer ring, inner ring,steel balls and cage. It can bear both radial and axial loads, can also be subjected to purely axial load, stability at higher speeds. Single row angular contact ball bearings can only withstand axial load in one direction. When the bearings under purely radial load, due to the line and rolling load radial load line is not the same in the radial plane, generating internal axial force, it must be installed in pairs.

1. single row angular contact ball bearings are single row angular contact ball bearings have the following structure:

(1) the separation of angular contact ball bearings

The bearing code number is S70000, its ring road does not lock, and the outline of the inner ring, cage, ball separation of components, which can be installed separately. Such as inner diameter of miniature bearing less than 10MM, for gyro rotor, micro-motors for dynamic balance, noise, vibration, stability has a higher requirement of appliance.

(2) non-separation of angular contact ball bearings

Channel lock for this type of bearing rings, rings of the two cannot be separated. By contact angle is divided into three types:

① contact angle α = 40 °, apply to take large axial loads;

② the contact angle α = 25 °, used for precision spindle bearings;

③ the contact angle α = 15 °, more for larger sizes of ball bearings.

(3) configured in pairs of the angular contact ball bearing

Paired angular contact ball bearings that are configured for both radial and axial loads, or you can take pure radial loads and axial loads in either direction. Such bearings by the factory preload requirements, combination matching pairs, available to users. When the bearings are mounted in the machine gets fixed after, completely eliminating the clearance in the bearing and outline of rings and balls in the preloaded State, thereby enhancing bearing steel.

Configured in pairs of angular contact ball bearings are available in three different configurations:

① back-to-back, post code for DB (for example, 70000/DB), this configuration is steel good, shoulder an overturning moment of the performance, can be subjected to bi-directional axial bearing load;

② face to face configuration, post code for DF (such as 70000/DF), rigidity and ability to withstand overturning moment of this configuration than the DB configuration forms, can be subjected to bi-directional axial bearing load;

③ tandem configuration, rear code-named DT (such as 70000/DT), this configuration is also available on the same bearing series of three or more bearings, but can only take a single direction axial loads. Typically, in order to balance and limit the axial displacement of the shaft and the other supporting Office installation to axial load bearing can bear the other party.

In addition, there is a any paired single row angular contact ball bearings. These bearings with a special process, two face-to-face or back-to-back, two-line combination in any way, axial clearance of paired combinations can be selected as needed, post code CA said smaller axial clearance, CB represents moderate axial clearance, CC larger axial clearance.

Universal pair of bearings, can be configured to have an interference by using requirements bearing, and later reset code GA, GB, GC said. GA paired with smaller interference; GB pairing with medium interference; a greater interference of GC said after the match.

2. double row angular contact ball bearings

Characteristics of double row angular contact ball bearing can bear both radial and axial loads combined load, limit the axial displacement of both sides of the axis.

Compared with the double-direction thrust ball bearings, these bearings the speed limit higher, contact angle 32 °, although good, affordable overturning moment, widely used in the front wheels of the car (some models also used the same dimensions of double row tapered roller bearings).

Double row angular contact ball bearings of the structure there are four variants:

(1) A diameter less than or equal to the 90mm bearings of standard design. No filling slots, thus subjected to bi-directional axial loads. With a lightweight glass fibre reinforced polyamide 66 cage, bearing temperature rise is small.

(2) A-type outer diameter is greater than the 90mm bearings of standard design. Filling slots on one side, with pressed window-type steel cages or solid cage of brass.

(3) E-type is a reinforced structure, with filling slots on one side, can fit into a larger number of steel balls, high bearing capacity.

(4) with shields on both sides both sides-and a-type design with sealing ring type and e-type design of double row angular contact ball bearings are available with shields on both sides (non-contact) or seals (contact). Sealed bearings are filled with rust inhibiting lithium base grease, operating temperature -30~+110 degrees centigrade. During use do not need lubrication, installation should not be heated, and should not be cleaned.

Double row angular contact ball bearing installation attention should be paid, although subjected to bi-directional axial bearing load, but when filling slots on one side, you should be careful not to allow the main axial loads through the Groove edge on one side of the gap.

Common Causes of Bearing Failures

There are many causes of bearing damage. It is not always easy to determine the exact cause, but most bearing failures can be attributed to one or more of the following major causes:

Foreign Matter: One of the most common sources of trouble in bearings is wear and pitting caused by foreign particles. This could be in the form of dirt, abrasive grit, lint, dust, steel chips, etc.

Improper Mounting: Bearings should be mounted with a press fit on the rotating ring. Generally, the shaft rotates and the inner ring is mounted with a press or interference fit.

1. Mounting bearings on shafts by applying blows or pressure to the outer race will usually cause denting (true brinell)
2. Loose shaft fit – rotation of the shaft within the inner ring can produce heat and small loose particles of metal that will eventually get into the bearing, causing wear
3. Loose housing fit – damage similar to loose shaft fit
4. Excessive tight fits – (shaft and housing) can cause rings to crack. Usually causes excessive internal preload because of the removal of internal clearance. Causes high operating temperature and premature failure
5. Out of round housings – usually found in split housings where careful machining is necessary to obtain round housing. Causes localized overloading with abnormal wear on surfaces and retainer pockets. Early fatigue occurs in these areas
6. Poor finish on the bearing seat – a coarse finish on the bearing seat will soon break down causing a loose fit condition, previously described

Bearing Misalignment: A frequent source of trouble resulting in overheating and separator failure. Common causes are bent shafts, out-of-square shaft shoulders, out-of-square spacers, and out-of-square clamping nuts. Inspection of the raceways will show the ball track veering from one side to the other.

Vibration Brinell (False Brinell): Caused by the rapid movement of the balls in the raceway while the equipment is idle. Rolling elements quickly remove lubrication and, because there is not enough rotation of the bearing, fresh lubricant is not moved back into the spot. This means the bearing is sitting in one spot, devoid of lubrication, and the movement of the rolling elements wears away the metal. The indentations run axially across the races.

Electrical Damage (Fluting): When electric currents pass through a bearing, there is arcing and burning at the points between the races and the rolling elements where the current jumps the air gap.

Pitting or cratering of a bearing is caused by relatively large charges of electricity.

A line of small burns along the line of contact of the rolling elements is caused by a low current constantly passing through the bearing. This fluting or grooving is formed on all parts as the current continues to pass through the bearing, and the contact points change as the bearing rotates. The steel melts in the affected zone. Electrical damage will cause early spalling and results in a noisy bearing which will have to be replaced.

Improper Bearing Lubrication: Lack of or improper lubrication generally causes overheating or excessive wear in the bearing. These conditions can result from insufficient lubrication, improper lubricants, complete absence of lubrication, or insufficient lubrication due to loss through leakage. Also to be considered is the breakdown of lubricants either by oxidation or exposure to atmospheric conditions.

Bearing Fatigue: Fatigue means the fatiguing of the metal in the components of the bearing. It is a result of stress reversals produced when rotating members create flexing of the metal. Fatigue develops due to the magnitude of the load and the number of times it is repeated. Actually, the rolling elements create a wave of metal in front of them as they roll. Thus, the metal in the components is alternately put in tension and then compression. This action eventually results in flaking of the metal.

Bearing Corrosion: The finely finished surfaces of ball and roller bearings are readily subject to corrosion by water, acids, and other agents. Corrosion is basically abrasive in nature and will account for excessive or abnormal wear in bearings. Common causes of corrosion include moisture, acid action, poor or broken down greases, poor wrappings, and condensation resulting from excessive temperature reversals.

Defective Sealing: This enables foreign material and contaminants to enter the bearing, causing wear.

High Temperatures: High temperatures frequently cause premature bearing failure, the nature of the failure being predicated on the temperature to which the bearing is raised and the grease with which it is lubricated. Mild temperature elevations may cause grease to bleed which reduces the efficiency of the lubricant. Under increasingly elevated temperature conditions, oxidation causes loss of lubricating elements and the formation of carbon. The carbon thus formed may lock or jam the bearing. High temperatures may also reduce the hardness of the metal causing early failure. High temperatures can cause loss of internal clearance and preloading results. Many bearing failures can be traced to dirt. Cleanliness is always a must.

Storage: Dampness (rust) – store bearings in a dry room.

Unwrapping: Not sure of bearing numbers, tearing wrappings and boxes – lets in dirt, corrosion, etc.

Always take bearing to the place of installation before unwrapping. This keeps the bearing clean.

Make sure parts are clean.
If the bearing and parts are to be left out, cover to keep them clean.

From http://www.applied.com/site.cfm/CausesofBearingFailure.cfm

Ball bearing review

Ball bearing is a kind of rolling bearings, whose spherical ball is mounted between the inner and the outer rims, and able to withstand greater loads.

The ball bearing is composed of four basic components: ball, inner ring, outer ring and cage or retainer. Ball bearing for general industrial use meet the criteria for AISI 52,100, and its balls and rings are usually made of high chromium steel, Rockwell C-scale hardness is between about 61-65. Hardness is lower than the ball and ring, and its materials: metal (such as carbon steel, aluminum) or non-metallic (such as Teflon, PTEF, polymer materials). Turning friction resistance of ball bearing is smaller than journal bearings, so at the same speed, the friction temperature will be relatively low.