In the production and engineering world where machines are vastly used, a bearing is a mechanical component that is almost inevitable. The term is derived from the verb “to bear”. Bearings are found in various machines, but they mostly do their work in the subsurface.
The mechanical component confines relative motion between two parts to the desired motion. Bearings may be designed to provide free linear movement of moving parts or free rotation around a fixed axis. They may also prevent motion by controlling the vectors of normal forces that act on the moving parts.
In this reading, we’ll explore bearings, their applications, functions, parts, diagrams, types, and how they work. We’ll also examine their advantages and disadvantages.
Let’s get started!
What are Bearings?
A bearing is a mechanical part that allows linear or rotational movement and reduces friction between two objects. It eases the movement, reduces fatigue, and improves speed and efficiency between the parts.
This is to say the design of a bearing may provide free linear movement of the moving parts or free rotation around a fixed axis. Also, it may prevent a motion by controlling the vectors of normal forces that bear on the moving parts.
Although most designs of bearings are to facilitate the desired motion by minimizing friction. The two types of bearing available include contact and non-contact bearing.
The contact types of bearings are made to have mechanical contact with the equipment, such as, rolling, sliding or flexural bearings. On the other hand, non-contact bearings contains air, liquid, mixed-phase or magnetic bearing, lacking a mechanical contact and eliminating static friction.
What are the functions of bearings?
Below are the functions of bearings as they serve in various applications:
Apart from making machines work smoothly, bearing still accomplish the following two major functions.
- Friction reduction and ensuring ease of rotation: As friction is the most occur event between two rotating shafts especially when lubrication is eliminated. Bearings are used between the parts to make the rotation smoother. Note that some bearings allow lubrication. Energy consumption is cut down since the friction is reduced.
- Bearing protect the part that supports the rotation and maintains the position of the shaft: Another primary purpose of the mechanical component is to withstand a large amount of force between the rotating shaft and the part that support the rotation. Bearings maintain the exact position of the rotating shaft.
Applications
As shafts that are required to rotate are used in different kinds of machines, bearings must be a feature to offer their great benefits. The mechanical part is widely used in automobiles, airplanes, electric generators, refrigerators, air-conditioning, vacuum cleaners as well as home appliances.
With the list of these bearing applications, it seems we humans can’t do without them as it help to reduce friction and ease of movement. Below are the common applications that make use of bearings:
- Bicycles.
- Electrical Motors.
- Cars.
- Blenders.
- Dental Hand Tools.
- Anemometer.
- Aviation Cargo System.
- Trolleys.
- Fans.
- Engines.
Components and Diagram of a Bearing
The various parts of a bearing include:
- Inner Ring
- Outer Ring
- Rolling Element (Balls, Cylindrical Rollers, Spherical Rollers, Tapered Rollers, Needle Rollers)
- Cage (Retainer)
- Lubrication
- Other Optional Bearing components
- Shields
- Seals
What are the Types of bearings?
The various types of bearings include:
- Ball Bearings
- Rolling Element Bearings
- Tapered Roller Bearings
- Deep Groove Ball Bearings
- Angular Contact Ball Bearings
- Self-Aligning Ball Bearings
- Ball Thrust Bearings
- Roller Bearings
- Cylindrical Roller Bearings
Ball Bearings
The ball bearings are designed to withstand both radial and thrust loads. They are used in different applications of various sizes as bearings receive nomenclature based on rolling elements and share equally with ball bearings.
These types of bearings are widely used in automobile industries for parts such as steering, power train, driveshaft, etc. It can also be seen on home equipment and other industrial machines.
Ball bearings can support less weight, and they also have a unique structure that can withstand loads and have a unique structure. Ball-bearing parts include the inner race, outer race, rolling element ball, and cage.
The inner race is the part that enters a rotating shaft, which tends to rotate the axis, while the outer race is mounted on the housing. The rolling element ball transfers the load through the axis, while the cage prevents the balls from colliding with others.
Rolling Element Bearings
These types of bearings have rolling elements in the shape of balls or cylinders. This bearing help because it is easier to roll a wheel than sliding it on the ground. This is because the magnitude of rolling friction is lower than that of sliding friction.
The rolling element bearings are used to ensure the free movement of a body in rotational motion.
Rolling element bearing help to move the load without much friction as the sliding friction has changed because of the rolling friction. With this bearing, every linear motion in applications can be easily convert into rotational motion
Furthermore, a reciprocating pump convert rotational energy from a motor into translational motion. Although with the help of linkages, ball bearings are used to support motor shafts of other rollers in the assembly.
Tapered Roller Bearings:
The tapered roller bearings are designed to withstand large thrust and radial roads. It is widely used in the automotive industry due to the fact that it can raise heavy loads without destroying the wheels. These types of bearings generally start with the serial number “3”.
Parts of tapered roller bearings include inner and outer rings which have tapered rollers located between them. The inner ring with a rolling element forms a unit that is individually fitted on the outer ring.
The conical surface extends to allow the engagement to a single point on the bearing shaft. This indicates that the rolling conditions of the rolling elements are optimized.
The axial load capacity of this bearing is determined by the contact angle that corresponds to the angle of the outer surface of the raceway.
Deep Groove Ball Bearings
Deep groove ball bearings are the common types of ball bearing. They are located between two ring of balls that transmit the load and allows rotational motion between them. These ball are mounted on a retainer.
The design of these types of bearings are less complex and easy to install. They also require minimal maintenance, but careful installation is require to avoid bending the races. This is because they must fit into the shafts.
Deep groove ball bearing have low rolling friction and are optimized for low vibration and low noise applications. This is why they are often used in high-speed applications.
Ball Thrust Bearings
The ball thrust bearings can withstand thrust loads in low-speed and low-weight applications. It’s common on a bar chair to hold the seat as it contains rolling elements.
These types of bearings are special types of ball bearings as they cannot sustain radial loads at any amount. They are use when low noise and smooth operation are required, also on high-speed applications.
Furthermore, the word “push” indicates the transmission of thrust loads or axial loads. The ball thrust bearing generally begins with series “5”.
Single-direction and double-directions are the two variation of these types of bearing. Their selection relies on direction of the load.
Angular Contact Bearings
Angular contact bearings are also type of ball bearing with inner and outer races. These races are displaced with respect to each other along the bearing axis.
They are designed to absorb greater amounts of axial loads in both directions. This is why they are widely used in agricultural equipment, gearboxes, pumps, automobiles, and other high-speed applications.
The shaft in the inner and outer races help the axial load to be transferred through the bearing to the housing.
Roller Thrust Bearings
A roller thrust bearing can handle larger thrust loads, often seen in car transmissions to support helical gears. The thrust load is supported by the bearing.
These types of bearings have a cylindrical rolling elements instead of balls as load-carrying element between the races. They are available in various types, the right type can be selected after knowing the type and magnitude of the loading, service conditions and possibility of misalignment, and other factors.
Cylindrical Roller Bearings
Cylindrical roller types of bearings are the simplest form of roller bearing but they are capable of handling heavy radial load and high speed. Also, they offer low friction long service duration, excellent stiffness, and axial load transmission.
They are available as single-row, double row, and four-row types, as well as, split and sealed variants. The split variant are used for areas that cannot be easily accessible.
The sealed variants eliminate bearing contamination and also lubricant is retained, which help reduce the maintenance cost.
In addition, cylindrical roller bearings can have their load capacity increased by obviating the use of cages or retainers. They are usually in place to hold the rollers. With this, more rollers can be fitted to carry the load.
Self-Aligning Ball Bearings
The self-aligning bearing is often used when there is misalignment between the shaft and the housing that may occur due to shaft defection or coupling errors.
It contains inner ring that has deep grooves similar to deep groove ball bearings. Also, an outer ring that has a concave shape and this grants the inner ring freedom to adjust itself.
Factors for Selecting a Bearing
The following are factors you should consider for selecting the right bearing type:
- Ball bearings for low and medium loads.
- Roller bearings for heavy loads.
- Self-aligning ball or roller bearings for shaft misalignment.
- Radial thrust bearings for medium thrust loads.
- Cylindrical thrust bearings for heavy thrust loads.
- Deep groove ball bearings, angular contact bearings, and spherical roller bearing for axial and radial load components.
- Deep groove ball bearings, angular contact bearings, and cylindrical roller bearings recommended for high-speed applications.
- Double-row cylindrical roller bearing or taper roller bearing for system rigidity.
- Deep groove ball bearing for noise reduction.
How Does Bearing Work?
The working of a bearing is quite simple and easy to understand. It consists of a ball and an interior on the outside of the smooth surface which rolls. The ball has the same weight as the load and the force of the load enables the bearing to rotate.
The bearing experience two types of loads: radial and trust depending on the application. Bearing in electric motors and pulley combination experience radial load, which comes form the tension in the belt connecting the pulleys.
When the loads come form the weight of the objects it is said to be thrust loaded. The bearing in the hub of a car wheel is supported by both radial and thrust load.
In conclusion, a bearing is a great component whose purpose is to provide ease of both rational and linear movement between two objects. We have looked at the different types of bearings which we say that they classified into two types; radial and thrust bearings.
Advantages and Disadvantages of Bearings
Advantages:
- Small friction resistance and power consumption.
- High mechanical efficiency.
- Easy to start and start.
- Size standardization and interchangeability.
- Compact structure, light weight, narrower axial size.
- High precision, large load, and long service life.
- Automatic heart adjustment performance.
- Suitable for mass production.
- Lower friction torque than fluid dynamic pressure bearing.
- Less axial size than traditional fluid dynamic bearing.
- Can bear combined radial and thrust loads.
Disadvantages:
- High noise.
- Complex bearing seat structure.
- High cost.
- Fatigue of rolling contact surface can cause failure.