Why bearing is required

Additionally, some bearings can also support an axial load, provided that they do not have a shoulder on the inner and outer rings.

If this is the case, you will not be able to use your bearing to support an axial load. Tapered roller bearings can support radial, axial and combined loads both at the same time. The loads can be very heavy, due to their high rigidity.

If you are unsure between a ball bearing and a tapered roller bearing, be aware that a tapered roller bearing of equivalent dimensions can support heavier loads. We therefore recommend this type of bearing for uses such as machine spindles, vehicle transmissions from car to boat, helicopter , or the steering of car or truck wheels.

Like cylindrical roller bearings, needle bearings can come with or without a cage. If they have a cage then they can withstand a very high speed , while a needle bearing without a cage can support a very significant radial or axial load.

Also note that these bearings are small in size, and as such have a small footprint. They are regularly used in gearboxes, for example. Each type of bearing can be deep-groove, spherical or insert. Deep-groove bearings are the most common. Insert bearings are deep-groove bearings which, like spherical bearings, effectively support misalignment. They differ from spherical bearings in that they have a smaller swivel angle. The larger the swivel angle, the more the bearing will withstand misalignment.

Another factor to consider: depending on the use, you will need a rotating shaft for example wheel drive bearings for cars or a rotating hub like for washing machine bearings.

Then you will need to pay attention to how the bearings are assembled. If two bearings are too close together, you should use the O-assembly method so that the bearings do not interfere with each other. If this is not the case then the X-assembly method is perfectly suitable. Finally, each bearing has specific dimensions. These dimensions, expressed in mm, are subject to international standards. We therefore advise you to pay attention to the bore of the bearing, i.

Choice of lubricant is an essential factor in ensuring the proper functioning and long service life of bearings.

Lubricant does the following:. You have 2 choices: grease or oil. Generally speaking, grease lubrication is definitely the simplest and most efficient choice because it provides all the functions mentioned above and also allows for operation with low maintenance. Some of these industries are:. When selecting a bearing for a particular application, there are several considerations to keep in mind, including bearing friction, temperature, and lubrication. Along with the specific design and construction of the bearing, these three interacting factors can affect the overall performance.

Radial ball bearings are used primarily for radially loaded shafts and those with light axial loads. Angular contact ball bearings are designed to take higher axial loads in one direction in addition to their radial capacities. Ball thrust bearings are available which are specifically intended to take axial loads alone. The most common configuration for radial ball bearings is the single row version, which could be shielded or sealed depending on whether it is to be used within a housed area—a transmission, say—or in an exposed environment such as on a bicycle wheel.

The seals and shields keep lubricant in the bearing and dirt and debris out of it. Ball bearings are usually fitted with retainers which space the balls evenly between and around the perimeters of their outer and inner races. Roller bearings employ a host of different shapes for their rolling elements, including straight rollers, needle rollers, tapered rollers, spherical rollers, etc. Roller bearings are able to take higher radial loads than their ball bearing counterparts due to the higher contact area between the rollers and the races.

Some roller bearings are designed to take high thrust loads using tapered elements and races. Mounted bearings are ball, roller, or sleeve bearings which are furnished in housings, flanges, etc. Common mounting styles include pillow blocks, flanges, take-ups, etc. They are often used on conveyors where take-up assemblies provide adjustment for conveyor belt tension.

In selecting rolling element bearings, either ball or roller or as mounted units, designers usually consider a number of factors including loads, both their quantities and directions, the accuracy requirements of the shaft system, misalignment factors, speeds, noise, and friction.

Where radial loads are high, a designer may opt for a roller bearing over a ball bearing and might do the same where high axial loads are anticipated.

Where the bearing needs to be able to accommodate some shaft misalignment, the designer may elect a ball bearing where loads are normal or go to a spherical roller bearing which is also very capable of handling misalignment. Ball bearings tend to be better at handling high speeds than roller bearings, and in some cases where accuracy and low friction are paramount, such as machine tools, a ball bearing may be the only way of meeting the requirements.

Of particular interest in considering bearings are their static and dynamic load ratings. Bearing that are subject to high loads when they are not rotating can undergo a phenomenon known as brinelling, where the balls dent the races in the same place repeatedly.

The same loads applied to the bearing when running may cause less concern because any indentations will distribute around the bearing races and not pile up in the same spots each time. Bearing makers list bearing rated capacities for their bearings, which for ball bearings are identified as extra-light, light-, medium-duty, and so on, where the dimensions of the bore or shaft requirements increase to accommodate increasing loads.

The rated capacity is based on a statistical measure which states that a certain percentage of bearings will complete a stated number of revolutions without failing. These catalog numbers can be massaged to better pick the bearing suited to the actual conditions of use. Linear bearings are sized according to linear travel, total linear distance, load, precision requirements, etc. Linear bearings are used with ground shafting for dimensional accuracy and low-friction sliding.

Slide bearings are used to accommodate expansion and contraction in stationary structures such as bridges and building. Product search. Bearing Technical Calculation Tool. Basic Bearing Knowledge.

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So, just what kind of role do bearings play in allowing machines to operate smoothly? They fulfill the following two major functions. Function 1: Reduce friction and make rotation more smooth Friction is bound to occur between the rotating shaft and the part that supports the rotation. Function 2: Protect the part that supports the rotation, and maintain the correct position for the rotating shaft A large amount of force is needed between the rotating shaft and the part that supports the rotation.

Just how widely are bearings used? What would we do without them? But what about real cars? Steel-on-steel and steel-on-bronze rod ends have good wear-resistant sliding surfaces, but require regular lubrication. They are suitable for applications where heavy alternating loads are involved. In what concerns maintenance-free rod end bearings , these are usually made of materials like steel and PTFE composite or steel and PTFE fabric, in this case the friction forces being much lower.

These bearings are suitable for applications where a long bearing life is required, where relubrication would be difficult and where the loads have a constant direction. The most common type of plain bearing is the bushing or bush, which is an independent element inserted into a housing to provide a supporting surface. The shape is usually cylindrical, the standard configurations being the sleeve bearing and the flanged bearing.

Sleeve bearings have straight inside and outside surfaces and equal diameters, while the flanged ones have a flange at one end that is used for locating the element in an assembly, and sometimes also for covering the mounting holes and securing the bearing in place.

Additionally, plain bearings can be lined, in this case a different material being used for the inside and outside surfaces. Bushings are used for linear, oscillating and rotating movements, the straight sleeves being suitable for radial loads, while the flanged bushings are able to withstand radial and axial loads in one direction.

Unlike rolling-element bearings, plain bearings — including bushings — function via a sliding action. Their construction can be single- or multi-layered, depending on the needed strength. Plain bearings are made from a variety of materials, and are often self-lubricating, this particularity ensuring a smoother operation and greater durability. The most common materials used for bushings are cast and machined metals, ceramics, fiber-wound composites, stabilized polymer materials and combinations of these.

As for lubricants, both solid and fluid ones can be used, but the solid lubricants can usually operate at higher temperatures than oil- or grease-based ones. For some applications, bushings run dry, with no additional lubrication. The construction of bushings can be solid or with a split or clench.

The difference between the solid and the split bushing wrapped bearing is that the latter features a cut along its length, for easier installation. The clenched bearing is similar to the split one, but has a clench across the cut connecting the parts. In general, linear bushings are not pressed into a housing, but secured with retaining rings or with rings that are molded into the outer diameter of the bushing. When bushings are used similarly to washers, they are called thrust washers.

A particular type of bushing is the self-lubricating one, in which a solid lubricating film is created inside the bearing through transfer of a small amount of surface material. This happens in the initial run-in period of the bearing, but the amount of material transferred is small enough to not interfere with the functioning and load-handling properties of the bearing. The film is in contact with all the moving parts of the device, lubricating and protecting them, therefore it helps in extending the service life of the bearing.

By doing so it eliminates the need of extra lubrication and reduces the costs with maintenance. Self-lubricating bushings have the advantage of being more lightweight thanks to the thinner walls, and of heaving excellent wear resistance. They can withstand high loads and have a simplified design that makes them more economical in the long run. Also referred to as full bearings, two-piece plain bearings are used in industrial machinery where larger diameters are required, such as crankshaft bearings.

They are made of two parts called shells, which are kept in place using different mechanisms. If the shells are large and thick, a button stop or a dowel pin can be used for locating them. The button stop is screwed on the housing, and the dowel pin links the two shells together. Another possibility is to use a tab on the parting line edge that corelates with a notch in the housing, to prevent the movement of the shells after installation.

Rolling-element bearings are also called antifriction bearings , as they have lower friction and reduced lubrication requirements compared to plain bearings. Their role is to support and to guide rotating and oscillating machine elements, such as shafts, wheels or axels, and to transfer loads between the different components of an assembly. They come in standard sizes, are easy to replace and cost-effective.

By minimizing friction and enabling high rotational speeds, these bearings reduce the heat and energy consumption, leading to more efficient processes. Antifriction bearings usually consist of two raceways — an inner ring and an outer ring, rolling elements which can be balls or rollers, and a cage that separates the rolling elements at specific intervals and keeps them in place inside the raceways, while enabling them to rotate freely.

The raceways are the components of a bearing that support the loads placed on the device. When a bearing is mounted in an assembly, the inner ring of the bearing fits around the shaft or axle, while the outer ring fits on the housing. The rings are usually made of special chrome alloy steel with a high purity and hardness, and are hardened, ground and honed.

Ceramic and plastic materials may also be used, especially in sectors where a lighter weight may be necessary — for example, in the automotive industry.

Still, these materials cannot withstand the same temperatures or loads as steel. The cage holds the rolling elements in place and prevents them from falling out when the bearing is handled. Thanks to the design of the bearing, the load is never applied directly on the cage. This component can be manufactured using different methods, but the common types include pressed, formed and machined cages. As for materials, usual options include steel, plastic and brass.

Finally, the rolling elements fall into two main categories, that distinguish also the basic types of rolling bearings: ball elements, which are found in ball bearings, and rollers, which are found in roller bearings. In case of balls, the contact with the raceways is in specific points, while for rollers the contact surfaces are slightly bigger and linear. These particularities make ball bearings more suitable for applications where higher speeds are needed, as the small contact areas provide low rolling friction.

However, ball bearings have a limited load-carrying capacity, so in case of applications where heavier loads are involved, roller bearings may be preferred. Thanks to their larger contact with the raceways, roller bearings have higher friction and better load-bearing capacity, but lower speeds.

The rollers can come in the shape of cylinders, cones, spheres or needles, and are made from high purity chrome alloy steel, just like the balls. Sometimes, special materials like ceramics or plastic can also be used. Ball bearings are classified into two main groups, depending on the configuration of the rings: deep groove ball bearings and angular contact ball bearings. Both types can withstand radial and axial forces, therefore they can be further classified into radial ball bearings and thrust ball bearings.

Another classification criterion includes the number of rolling rows — single, double or four row, and the separation or lack of separation between the rings.

Considering all these criteria, we can distinguish several models of ball bearings: single row deep groove ball bearings , single row angular contact ball bearings, double row angular contact ball bearings , four-point contact ball bearings, self-aligning ball bearings , single direction thrust ball bearings and so on.

Ball bearings are used in a variety of applications, from simpler devices like skateboards to complex machines or engines. In the aerospace industry for example, bearings can be used in gearboxes, engines and pulleys. The materials these bearings are made of can include not only steel but also special ceramics like silicon nitride or titanium-carbide coated C stainless steel.

Other common applications of ball bearings include electric motors and generators, pumps and compressors, blowers, fans, gear boxes and drives, turbines, farm machinery, conveying systems, oil field machinery, robotics, industrial valves and so on.

Ball bearings are the most common type of rolling-element bearing, and from these, the most used ones are deep groove ball bearings. These are radial bearings which can have a single or a double row of balls, and come in different construction types, such as Conrad type or slot-fill radial bearings. The name of these compounds is given by the deep grooves formed on the inner and outer rings. In the Conrad design , the inner ring is initially placed into an eccentric position relative to the outer one, and the balls are inserted into the bearing through the gap that forms between the two rings.

Once they are distributed evenly in the bearing assembly, the rings become concentric, therefore the cage can also be added to the bearing. The role of the cage, as previously mentioned, is not to support loads, but to keep the balls in place during operation.

The inner ring is usually fastened to the rotating shaft, while the outer ring is mounted onto the bearing housing. When a load is applied on the bearing housing, it is transmitted from the outer race to the balls, and from the balls to the inner race. Deep groove ball bearings are suitable for applications where high loads and speeds are involved. In the slot-fill design, more balls can be assembled between the two rings, therefore the radial load capacity of the bearing is higher than in the Conrad bearings.

However, the axial load-bearing capacity of these components is not that good. Deep groove ball bearings are available as open type bearings that allow for easy lubrication, but have the disadvantage that the balls can collect dust. Bearings with shields or seals on both sides are lubricated for life, therefore require minimum to no maintenance.

Bearings with shields or seals are also called capped bearings. Although the design may vary, the seals are fitted in general on the outer ring, and can come in the form of non-contact seals, low-friction seals or shields.

Shields are used in applications where the inner ring rotates and are fitted on the outer ring, forming a narrow gap with the inner ring. They protect from dust and dirt and are generally made of sheet steel. Seals are generally more effective than shields as they create smaller gaps with the inner rings. They can be operated at speeds similar to shields or higher, and are made of sheet steel reinforced NBR or similar materials, which are resistant to wear. As for the cages in deep groove ball bearings, their construction can also vary, but some common designs are ribbon-type cages made of steel or brass sheets, riveted cages of brass sheet or steel, machined brass cages or snap-type cages made of polyamide 6,6.

To conclude, deep groove ball bearings are versatile devices, suitable for high and very high speeds, robust in operation and requiring little maintenance. They can accommodate radial loads and axial loads in both directions and in the single-row design, deep groove ball bearings are the most widely used type of bearing. Angular contact ball bearings also come in various designs, being available as single or double row, matched pair or four-point contact bearings. Their construction allows these elements to withstand both axial and radial forces, therefore they are suitable for applications with high loads and speeds.

Unlike deep groove ball bearings, angular ones use axially asymmetric races, the contact angle between the rings and the balls being formed when the bearing is in use.

A particularity of these bearings is that one or both of the ring races — typically the outer ring - have one shoulder higher than the other. These bearings function properly when assembled with a thrust load. The contact angle usually varies between 10 and 45 degrees, and when this angle increases, the thrust capacity also increases. Angular contact bearings can come in different design styles, with seals or shielding. These serve not only as protection from contamination but also as retainers for lubricants.

These bearings can be made from stainless steel, ceramic hybrid materials or plastic, and may be plated with chrome, cadmium or other materials. Also, they can be pre-lubricated, re-lubricated or can feature solid lubrication. Roller bearings are classified into different types depending on the shape of the rolling elements. The main categories of roller bearings include cylindrical bearings, needle bearings, tapered bearings and spherical roller bearings.

Cylindrical roller bearings are engineered to withstand heavy radial loads and moderate thrust loads, and they contain cylindrically-shaped rollers designed to reduce stress concentrations. The rollers are in linear contact with the raceways, and are usually made of steel. Materials like polyamide or brass can also be used in cylindrical roller bearings for the cages.

These types of bearings have low friction and long service life, low noise and heat generation, and can be used in applications where high speeds are involved. Cylindrical roller bearings come in different styles, the designations varying depending on the manufacturer. These bearings can be classified based on the number of roller rows. From this point of view, these machine components are divided into single row cylindrical roller bearings, double row and four row cylindrical roller bearings.

In the single row models, for all designations, the inner and outer rings are separable, meaning that the inner ring with roller and the cage assembly can be mounted independently of the outer ring.