The Modern Development of AntiFriction Bearings

Precision

Since the assembly of ball and roller bearings involves very careful processing of the finest material, and delivery to the user in a finely adjusted condition , ball and roller bearings are used where precision of rotating elements must be of the highest order.  The external dimensions of bearings are standardized as to nominal diameters and working tolerances, and in ball bearing and roller bearing plants of the present day the finest equipment is used, not only for processing but for the inspection of component parts, in order to insure the precision demanded by the principle of the bearing and the service into which it is to be placed.

Accurate and true-running bearings are for the first time possible with the ball and roller types, vibration, chatter,m and other undesirable conditions which may arise in plain bearings being largely eliminated by the proper selection and applications of anti-friction bearings to many types of machinery.  Gears can be kept in exact alignment and adjustment.  Grinding wheels can best supported as to produce the finest work, woodworking tools can be made to produce a more accurate finish, and at higher rates of speeds than would be possible with plain bearings.  Parts which must be maintained with small but definite clearances are most successfully carried on ball bearings, and these qualities are only available during the initial period of operation but extend through their long and useful life.

Elsewhere are described the various degrees of precision  which are available to the user of ball bearings.  The so-called S.A.E. tolerances themselves are precision tolerances, but for even finer requirements still further degrees of accuracy are obtainable.

Lubrication

The load-carrying element in the plain or journal bearing is a firm of lubricant forced between the rotating and stationary surfaces by the action of the journal itself, and by the tendency of the lubricant to adhere to the stationary surface on the other side.  This action drives a wedge of lubricant between the surfaces and separates them from actual metal – to – metal contact.  The plain bearing is forced to rely upon this action for its effectiveness , while in the ball and roller bearing this condition does not apply, as rolling elements are interposed between the raceways.  Lubricant, therefore, takes what may be termed a secondary (although important) place in the functioning of an anti-friction bearing.  It lubricate the retainers, where they are in slight sliding contact with the balls, as well as the twilight zone where rolling friction verges on sliding friction, and it serves as a protector for the finely finished surfaces of the balls and raceways.

These considerations are responsible for the starting friction of ball and roller bearings being very low, and of plain bearings high.  They press lubricating problems on teh designer and user of the plain journal to a far greater extent than with anti-friction bearings, where the rolling elements are kept in their proper relation with respect to the races by the retainer or separator, and maintain their location during service — in operation and out.

The design of housing for lubrication and the selection procedure in applying lubricant to the various ball bearing designs are treated separately in this catalog.  In summing up, it is well to remember that anti-friction bearings will require comparatively little lubricant and offer a fairly wide choice of grease or oils.  Maintenance is low and periods between lubrication can be unusually long.

Most reasons to use composite plastic bearings

Composite plastic bearings combine thermoplastics, fibrous reinforcements, and solid lubricants for tailored bearing solutions with predictable lifetime in a wide variety of applications. These bushings run without maintenance, external lubrication, resist corrosion and debris, fit precisely with little creep, conduct heat efficiently, and dampen vibrations while maintaining high compressive strength. Read on for the top ten reasons to consider plastic bearings.

1. Lighter weight than metallic bearings

Swapping metallic plastic bushings to composite plastic bushings can reduce weight by 25% or more. The difference in density between composite plastic materials and metals - 1 to 3 g/cm3 vs. 7 to 9 g/cm3 - the weight reduction available with plastic bearings is obvious.

2. Corrosion resistance

Metal-free plastic bearings do not rust, and most available materials will not corrode in acidic or basic solutions, or when exposed to traditional lubricants. The product line also includes bearings that are able to resist harsh acids, such as hydrochloric acid, as well as UV and other high-energy radiation. Chemical resistance can change with temperature and chemical concentration, so be sure to take your specific application conditions into account.

3. 100% self-lubricating

plastic bearings are designed to run dry, without any external lubrication. Fiber reinforcements create millions of tiny chambers, which house particles of solid lubricant which are released as friction against a shaft occurs. Homogeneous blending of the plastic material means that lubricant cannot be pressed out, and will last throughout the entire service life of the bearing.

4. Forgiving of shock and edge loads; vibration dampening

Plastic bearings run quietly and absorb or dampen vibrations. Their mechanical loss factor, and indicator of vibration-dampening capability, is up to 250 times that of metallic bearings. The fiber-reinforced material blends are tailored to specific application requirements, helping bearings stand up to shock and edge loads in a wide range of application settings

5. Pairs well with a range of shaft materials

Plastic bearings can pair with any shaft material without corrosion issues, but not all shaft-bearing pairs are equal. Extensive testing and experience have provided with a massive database of bearing wear results when paired with different shaft hardness, roughness, and materials makeup. (Excellent wear performance depends on pairing the right bushing material with the shaft.

6. Excellent wear rates

When a shaft with a composite plastic bushing starts to move, bits of solid lubricant and thermoplastic abrade to fill shaft imperfections and provide continuous lubrication, minimizing stick-slip and wear. Abrasion rates drop dramatically after initial startup, becoming negligible during continuous operation. The plastic bearing offers optimal wear thickness throughout the entire wall thickness of the bearing.

7. No maintenance required

Based on results of thousands of empirical tests specialists can recommend plastic bearings that are ready to “fit and forget.” Test data allows engineers choose the best bearing/shaft combination and predict maintenance-free service life based on application factors. When combining this with the lack of required external lubrication, you get a completely maintenance-free bearing solution.

8. Dirt and dust resistance

Metallic bearings wear prematurely if abrasive dirt particles get into them, but plastic bearings are able to ‘absorb’ these particles, incorporating them into the plastic material itself. Additionally, the lack of required grease and oil does not attract debris.

9. Special application materials available

If your application requires specific material requirements, such as FDA or EU-directive compliance, the material range offers a number of applicable products and materials. 

New ideas about Special housing keeps bearings cool

Oil in the reservoir is below the bearing, eliminating heat from the bearing churning through the oil. For more cooling, optional single or dual tubes, each operating independently, send water into and out of the housing. Tests show that one tube using 59F water reduces bearing and oil temperature by 12 and 32F, respectively. Two cooling tubes reduces them by 16 and 38F.

The design uses fewer parts than the company’s last bearing housing. For example, the previous housing needed up to 20 bolts on end covers. The new design has no end covers. Fewer parts reduces the risk of oil leakage. Labyrinth seals prevent contaminants from entering the bearing and are built to retain oil, feeding it back into the cast-iron housing. 

Automotive Bearings Market Growth with Worldwide Industry

Bearings are used to enable rotational or linear movement, and to disable the unwanted friction and handling stress. Bearings are integrated in automotive to constrain the relative motion and allow desired motion, due to which, a vehicle can enhance its speed and efficiency. Vehicles have many rotating parts, and bearing are used in almost all parts. For example, axle bearings are used to enable wheel axles to turn.

The structure of bearing is simple, it has a ball, which has internal & external smooth metal surfaces, which helps bearings to move. The ball in the bearing is responsible for carrying the weight of the load, and load’s weight is responsible for giving a push to the bearing’s rotation.

There are different types of bearings used in the automotive, such as ball, roller & thrust bearings, housed units, needle roller bearings, plain bearings, plummer blocks, sleeves, slim section bearings, spherical roller bearings, etc. For instance, applications such as wheels and transmissions use roller bearings, as roller bearings support heavy-duty applications.

The demand for automotive bearings is growing with the increase in the automotive production globally, especially in the Asia Pacific and Western Europe. The demand for vehicles with technologically advanced solutions is fueling the growth for the global automotive bearings market. Growing demand for automotive bearing in developing countries and above factors are propelling the growth for global automotive bearings market.

Bearings for Mechanical and Electrical Products Market attracts Heavy Vehicle Market

The bearing for ‘Mechanical and Electrical’ market encompasses rolling bearings, comprising ball and roller bearing assemblies of several designs, including mounted-bearing units.

The mechanical equipment bearing markets accounted for most of market, and finds major application in light and heavy machines and equipment, as well as aerospace, off-highway and railway vehicles, bearings are classified into ball bearings, plain bearings, roller bearings, fluid bearings, magnetic bearings, jewel bearings and flexure bearings.

Competitive landscape for each of the product types is highlighted in this report along with the key players profiled with attributes of company overview, financial overview, business strategies, product portfolio and recent developments.

Bearing Steel Market Confident Of Improving Strength & Durability of Bearings

Bearing Steel Market deals with the manufacture and development of special steel which contains the high performance ability of being able to withstand high levels of wear, tear and rolling fatigue. The chromium as well as engineering versions of bearing steel are popularly used as vital elements for bearings as well as for a variety of other purposes. This type of bearing steel contains a maximum of 1% carbon and a manganese content of somewhere between 0.3-0.9%. Various products like the ball, roller, bearing rings, etc., are also made from this type of steel.

Bearing Steel in Global market, especially in United States, Canada, Mexico, Germany, France, UK, Italy, Russia, China, Japan, India, Korea, Southeast Asia, Australia, Brazil, Middle East and Africa. This report splits the global market into several key Countries, with sales, revenue, market share of top 5 players in these Countries, from 2012 to 2017 (with a forecast period of 2017 – 2022).

Aims to empower our clients to successfully manage and outperform in their business decisions. We do this by providing Premium Market Intelligence, Strategic Insights and Databases from a range of Global Publishers.

What’s the Difference Between Bearings?

Bearings are used to help reduce friction. Metal-upon-metal contact produces large amounts of friction. The friction adds to wear and tear of the metal, producing grinding that slowly degrades the metal. Bearings reduce friction by having the two surfaces roll over each other, reducing the amount of friction produced. They consist of a smooth metal ball or roller that rolls against a smooth inner and outer metal surface. The rollers or balls take the load, allowing the device to spin.

The load acted upon a bearing is either a radial or thrust load. Depending on the location of the bearing in the mechanism, it can see all of a radial or thrust load or a combination of both. For example, the bearing in the wheel of your car supports a radial and a thrust load. The weight of the car on the bearing produces a radial load while the thrust load is produced as the car turns a corner. Here we will examine some types of common bearings.

Ball Bearings

Ball bearings are most common type of bearing and can handle both radial and thrust loads. Ball bearings are also known as deep-groove single-row or Conrad bearings. The inner ring is typically fastened to the rotating shaft and the groove on the outer diameter provides a circular ball raceway. The outer ring is mounted onto the bearing housing. The ball bearings are housed in a race and when the load is applied, it is transmitted from the outer race to the ball and from the ball to the inner race. The raceway grooves have typical curvature radii of 51.5% to 53% of the ball diameter. Smaller curvature raceways can cause high rolling friction due to the tight conformity of the balls and raceways. Higher curvature raceways can shorten fatigue life from increased stress in the smaller ball-race contract area.

1. Ball bearings, also known as Conrad bearings, are typically used in small load applications.

The contact points between the ball and the outer race is very small due to the spherical shape of the bearing. This also helps the ball spin very smoothly. Since the contact point is so small, the bearing can become overloaded at a specific point causing the ball bearing to become deformed. This will ruin the bearing. Ball bearings are typically used in applications where the load is relatively small.

2. The table above lists some general types of ball bearings and their typical load capabilities.

Straight Roller Bearings

Straight roller or cylindrical bearings run in cylindrical raceways and have low-friction, high-radial load capacity, and high speed capability. Roller bearings are cylinder-shaped bearings where the point of contact between the bearing and the race is a line rather than a point. Load is distributed over a larger area and allows the bearing to handle a greater load. To minimize its tendency to skew, the roller’s length is not much greater than the diameter of the roller.

3. Straight or cylindrical roller bearings can be found in applications like conveyor-belt rollers, which are required to hold heavy radial loads.

Their usual design is free to float axially, and they have roller-guiding flanges on both sides of one ring and none on the other side. This allows for the bearing to expand due to thermal activity when used in combination with a ball bearing’s fixed location at the opposite end. A thrust load can be supported in one direction if a guiding flange is added on one of the opposing rings’ side. A second flange can be added for two-directional thrust capacity.

Tapered Roller Bearings

4. Tapered roller bearings are designed to withstand a radial and thrust load, and can be found in car hubs due to the amount of radial and thrust loads they can carry.

In a tapered roller bearing, the rings and the rollers are tapered in the shape of truncated cones to simultaneously support axial and radial loads. The ratio of the loads depends on the angle of the axes between the roller and bearing. The greater the angle is the greater axial load can be supported. The contact angle for most tapered roller bearings range is between 10 to 16 degrees. For higher thrust-load capacity, a 30-degree contact angle is used.

5. Tapered bearings are mounted pairs since they handle radial loads better than a single row of tapered bearings. For heavy-duty applications, two or four rows of tapered rollers are combined in a single unit in large bearings.

Spherical Roller Bearings

Spherical roller bearings typically consist of two rows of barrel-shaped rollers running in two raceways. One is on the inner ring and the other is on a continuous spherical surface ground on the inner diameter of the outer ring. This allows the bearing to operate with some misalignment. Spherical rollers have barrel profiles that closely match the raceways profiles, hence making them robust and having a high load capacity. They are mounted in pairs inside the bearing housing and are faced in opposite directions. This is done so that the load can be supported in either direction.

6. Spherical roller bearings are used in car hubs and can support large radial and thrust loads.

Needle Roller Bearings

Needle roller bearings use elongated cylindrical rolling elements with small diameters. They are used in applications where radial space is limited. The diameter to length ratio for the needles varies between 1-to-2.5 and 1-to-10. Due to their small size, they cannot be guided accurately and generate high amounts of friction. They are used at low speeds and oscillating motions as a result. Cages may be used to help guide the needles and improve retention.

7. Needle roller bearings are used in designs that have heavy space restrictions.

Thrust Bearings

Designed to handle high thrust loads, roller-thrust bearings are typically found in gearsets used for car transmissions between gears or between the housing and rotating shafts. The angled teeth found in helical gears used in car transmissions produce a high thrust load that is supported by the roller-thrust bearings. Roller-thrust bearings slide within a roller-race contact to handle the surface-speed variation that comes as a result of the varying diameter across the contact zone.

8. Ball-thrust bearings are designed to handle almost exclusively thrust loads in low-speed, low-weight applications. An example of its use would be in bar stools where they are used to support the seat.

Ball-thrust bearings are comprised of two grooved plates with a set of balls between them. The ball-race contacts have a sliding action that is increased at high speeds by the centrifugal force on the balls. Cylindrical roller thrust bearings are limited to about 20% of the speed of its radial bearing counterpart and ball-thrust bearings are limited to 30% of the speed of their counterpart.