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[url=http://www.ghbearings.com/ball-bearings/]Rolling-element bearings[/url] are used to ensure smooth, efficient operation in many machines with rotary motion—from car wheels, engines and turbines to medical equipment. A ball bearing is a type of rolling-element bearing that serves three main functions while it facilitates motion: it carries loads, reduces friction and positions moving machine parts.
Ball bearings use balls to separate two “races,” or bearing rings, to reduce surface contact and friction across moving planes. The rotation of the balls causes a reduced coefficient of friction when compared with flat surfaces rubbing against each other. Because there is little surface contact between the balls and races, ball bearings typically have a lower load capacity for their size than other rolling-element bearings.
There are a variety of different designs and applications for ball bearings, and their design is specific to their industrial application and load type. Some common designs of ball bearings include:
Angular Contact Bearings: designed to work under combined radial and axial loads.
Axial Bearings: also called thrust ball bearings, these are designed to work under force applied parallel to the bearing’s axis, or thrust loads.
Deep-Groove Bearings: designed to carry both radial and light axial loads.
Linear Bearings: designed to allow movement in one direction along a linear axis.
Self-aligning Ball Bearings: bearings with two sets of balls that are self-aligning and to carry both radial and light axial loads.
High-Speed Angular Contact Bearings: another type of precision ball bearing is a high-speed angular contact bearing. As the name implies, high-speed bearings are designed to handle high RPMs with precision and accuracy.
Ball bearing sizes vary according to their use. The width of the bearing also depends on the application. For example, thin section bearings are used in situations where space is at a premium. The difference between the diameter of the outside and inside races and width is minimized, allowing for compact designs.
The materials used in ball bearings depend on their application. The vast majority of ball bearings are made from steel. Other material types include stainless steel bearings for improved corrosion resistance and hybrid ball bearings for which ceramic balls are the moving parts of the bearing between the inner and outer races to reach high rotational speeds.
Roller Bearings Information
[url=http://www.ghbearings.com/roller-bearings/]Roller bearings[/url] are used to replace sliding movement with low friction, rolling motion in rotary applications. The principal types of roller bearings are cylindrical, spherical, and tapered. In general, roller bearings offer higher load capacities than ball bearings of the same size.
Types
There are five main types of roller bearings:
Cylindrical Roller Bearings have high radial-load capacity and moderate thrust loads. They contain rollers which are cylindrically-shaped, but crowned or end-relieved to reduce stress concentrations. Cylindrical roller bearings are similar in design to needle roller bearings but the dimensions of diameter and roller length are closer in magnitude.
Spherical Roller Bearings are self-aligning, double row, combination radial and thrust bearings. They use a spherical or crowned roller as the rolling element.
how to select roller bearingsTapered Roller Bearings consist of an inner ring (cone), an outer ring (cup), a cage and rollers, which are profiled to distribute the load evenly across the roller. During operation, tapered roller bearings create a line contact between the raceway and rolling element, distributing loads across a larger area.
Needle Roller Bearings are a type of cylindrical roller bearing where the length of the roller is much larger than then the diameter. Needle roller bearings are designed for radial load applications where a low profile is desired.
Thrust Bearings are designed for pure thrust loads, and can handle little or no radial load. Roller thrust bearings use rollers similar to other types of roller bearings
Components
Radial type roller bearings (cylindrical, tapered, spherical, and needle) consist of four basic components, an inner ring, an outer ring, rollers, and a cage (roller retainer). Under normal operating conditions, bearing rings and rollers carry the load while the cage spaces and retains the rollers on the cone.
how to select roller bearings
Comparison of Cylindrical Roller Bearing and Ball Bearing Components
Image Credit: bridgat
Roller thrust bearings are designed to carry pure thrust loads. Like radial roller bearings, roller thrust bearings also consist of two rings, rollers, and a cage (roller retainer). However, instead of an inner and outer ring concentric to the axis of rotation, they have two rings or thrust washers on either side of the roller.
How To Install A Pillow Block Bearing
[url=http://www.ghbearings.com/pillow-block-bearings/]A Pillow Block Bearing[/url] is a mounted anti-friction bearing that is contained within a solid cast iron, ductile iron or cast steel housing unit. Also referred to as a housed bearing unit, meaning they are self-contained, greased, sealed and ready for installation on the equipment. Pillow Block bearings are typically bolted to a surface, so that the attached shaft runs parallel with the surface. There are two types of housings used for pillow block bearings, solid and split housings. Solid housed bearings are single-piece housings, while split housed bearings are two-piece housings. Pillow block bearings can contain several types of bearings, including ball, roller and tapered. Shaft attachment devices can be set screw, eccentric lock, single or double set collar, concentric lock or tapered adapter. Each device has their own positive and negatives. Seals vary as well, including clearance seals, light contact, heavy contact and auxiliary type seals. Pillow Block Bearings, in most cases, also come in a fixed or expansion version. The expansion bearings allow for shaft growth and can reduce the risk of loading one bearing against the other. Choosing the best shaft mount device and seal will prolong bearing life. When installed properly, pillow block bearings can last years without needing to be replaced. Follow these steps to ensure minimal downtime and a longer service life.
*This procedure is for the most common shaft locking device set screw or set collar, utilizing a fixed and expansion unit, but the general guidelines apply to all bearing installs.
1) Check and Clean the Shaft
First, check your shafting to ensure it is clean, round, straight, free of burrs and nicks and is not undersized or oversized, per the manufacturers specification. Use fine sandpaper or scotch bright to clean the shaft of any rust. Then use a light coat of oil to remove any debris.
2) Position the Bearings on the Shaft
When placing the bearing on the shaft, if it is necessary to tap the bearing into place, use a mallet and a hardwood block or soft steel tube against the inner ring. DO NOT strike or exert pressure on the housing or seals.
3) Lightly Bolt the Housing to the Mounting Structure
Locate the shaft in position by lightly bolting the housing to the mounting structure. Bridge over the housing mounting bolt slots with heavy washers, or heavy spring lock washers. This may help prevent loosening.
What are the characteristics of joint bearing?
The [url=http://www.ghbearings.com/joint-bearings/]structure of the joint [/url]bearing is simpler than that of the rolling bearing. It is mainly composed of an inner ring with an outer spherical surface and an outer ring with an inner spherical surface.Joint bearing is generally used for low-speed swing motion (that is, angular motion). Since the slidi
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