You have probably encountered a fidget spinner at some point in the past few years given the frequency with which new fads appear. No age group was spared as these tiny whirring toys swept the globe. They started creating their own versions when their designs lost their appeal to overly creative people by selecting the ball bearings and encasing them in elaborate devices of their own design.
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What Are Bearings?
Bearings are “parts that assist objects’ rotation”. Inside the machinery, they support the shaft that rotates.
Automobiles, aircraft, electric generators, and other devices use bearings. Even common household appliances like air conditioners, vacuum cleaners, and refrigerators use them.
Bearings provide stability for the rotating shafts of things like wheels, gears, turbines, and rotors. in those machines, allowing them to rotate more smoothly.
In this way, all sorts of machines require a great many shafts for rotation, which means bearings are almost always used, to the point where they have become known as “the bread and butter of the machine industry”. Although bearings may appear to be straightforward mechanical components at first glance, we would not be able to survive without them.
The Role And Importance Of Bearings
What kind of a role do bearings play in facilitating smooth machine operation?
These two crucial tasks are carried out by them.
Function 1: Reduce Friction And Make Rotation More Smooth
Between the rotating shaft and the component supporting the rotation, friction is unavoidable. These two parts are connected by bearings.
By lowering friction, the bearings enable more fluid rotation. The amount of energy consumed is decreased as a result. This is the sole purpose of bearings.
Function 2: Protect The Part That Supports The Rotation, And Maintain The Correct Position For The Rotating Shaft
The part that supports rotation must exert a significant amount of force on the rotating shaft. In addition to keeping the rotating shaft in the proper position, bearings serve the dual purpose of preventing damage to the component supporting the rotation from being caused by this force.
We can use our machines repeatedly for a considerable amount of time thanks to this bearing function.
What Would We Do Without Them?
Let’s consider how much our daily activities rely on bearings. It’s a little challenging to imagine them because you don’t typically see them, isn’t it? Given that we are all familiar with cars, let’s talk about them a little.
You must have used an electric toy race car set at least once when you were a kid, right? The bearings that held the wheels in place may be in your memory.
How about actual automobiles? How many bearings are needed for a single car?
① Equipment (parts) For Generating Driving Force
Examples: Alternators, turbochargers and the like
② Equipment (parts) For Steering
Examples: Steering gears, pumps and the like
③ Equipment (parts) For Transmitting Driving Force
Examples: Transmissions, differential gears and the like
④ Equipment (parts) For Driving The Car
Examples: Wheels, suspension and the like
Bearing Surfaces
A ball bearing is a type of machine part used to support relative motion and lessen friction between moving parts.
Types Of Bearings
1. Sliding Bearings
The most basic type of bearings are sliding ones, which have plain or grooved surfaces on which machine parts can slide. They can support both linear and rotary movement and are cheap to produce.
A shaft in a hole serves as the simplest illustration of a sliding bearing. It can move linearly along it or rotate about its own axis inside the hole. Without bearings, the shaft movement in the hole may cause the shaft or the hole’s walls to erode.
Rotary sliding bearings have a sleeve-like design that allow the shaft to rotate inside. The shaft is supported as it moves by the sleeve, which slides into the hole. Depending on the application, it can either be a single piece (bushing) or a split piece (journal bearing).
On the other hand, linear sliding bearings permit the shaft to move along the hole. To reduce friction between the moving parts in sliding bearings, external lubrication is necessary.
They can be constructed from a variety of materials, including cast iron, Babbitt, bronze, and other alloys containing zinc, and they are low-cost to maintain. Depending on the application, bushings may also be made of rubber.
Some common sliding bearing examples include:
- Crankshafts in car engines that use journal bearings
- Door hinges that use bushing
2. Rolling Bearings
The most common type of bearings, known as rolling bearings, consist of rolling elements enclosed in a housing that permit relative motion between machine parts. Depending on the use of the bearings, the rolling elements may be balls or cylindrical rollers. Cylindrical element bearings have a larger contact area than their equivalent-sized ball element counterparts, which allows them to support higher loads. It is possible to support linear motion with the rolling elements arranged in a straight line, and rotary motion with the rolling elements arranged in a circle.
Conical, tapered, and needle rolling bearings are just a few of the different configurations that are available.
Stainless and chrome steel are frequently used in the production of rolling bearings. However, silicon nitride may also be used to make them. The best performance from rolling element bearings requires lubrication, but high-temperature applications can also use specially designed dry bearings. Even though they are frequently used in daily life, they can sometimes go unnoticed. A few examples of rolling bearings include:
- Bicycle pedaling mechanisms
- Drawer sliders
- Skateboard wheels
3. Flexure Bearings
There is another class of bearings that addresses failure brought on by repeated flexing, as opposed to the bearings previously mentioned that reduce failure due to friction. The term “flexure bearings” also applies to these bearings. They join two surfaces that are inclined with respect to one another, i.e., by bending or stretching.
The material used to make the flexure bearing is designed to withstand repeated stress cycles without fatigue failure. Its life cycle is shortened and it may fail before its time if it is repeatedly stretched past the tolerable limit. Flexure bearings can be made of different materials, such as metals or plastics, and can have either a linear or spiral shape depending on their intended use.
The flip lid that is frequently found on plastic boxes containing mints is an everyday illustration of a flexure bearing. They are additionally used with long beams to allow for movements like sag.
The Initial Purpose Of Using A Bearing
When machine parts move in relation to one another, the surfaces that come into contact erode and cause material loss. This alters the distances that must be kept between them, decreasing efficiency and possibly even leading to machine failure.
Bearings are “sacrificial” contact surfaces that are weaker than the machine part with which they come into contact but strong enough to withstand repeated friction and heat cycles. By limiting friction-related wear to the bearing surfaces only, this avoids the need for pricy repairs.
Life Of A Bearing
The L10 value frequently serves as a representation of the theoretical bearing life. This is the amount of time a bearing is in use for before 10% of the bearing surfaces fail.
The L10 value, however, is purely theoretical since it relies on perfect operational circumstances, including ideal lubrication, a dust-free environment, and correct alignment. Estimating the “installed life” of a bearing is very challenging because this is not always possible.
A Note On Unconventional Bearings
1. Jewel Bearings
In the manufacture of mechanical watches, special slider bearings called jewel bearings are employed. Synthetic sapphire or ruby is used to line the bearing surfaces, reducing friction while maintaining the system’s dimensional accuracy.
2. Magnetic Bearings
Using a powerful magnetic field to levitate their components, magnetic bearings are frictionless bearings. They are an emerging trend because they can operate in a vacuum and without lubrication, even though they haven’t yet become widely known due to their size and high cost. Machines like compressors, turbines, motors, generators, and pumps increasingly use magnetic bearings.
3. Fluid Bearings
The surface of air hockey tables is a common example of fluid bearing surfaces
Another type of contactless bearing is a fluid bearing, which works by shielding the moving surfaces with a thin film of pressurized fluid. Fluid bearings have the benefit of having almost no wear and operating quietly, which makes them suitable for high-speed and high-precision applications.
In hard drive motors, they are frequently employed. The surface of an air hockey table is another typical example of one of these bearing surfaces; the puck “floats” on a layer of air that emerges from tiny holes in the table.
