"Bearings" are a type of mechanical part, but do you know what they do? They are, in fact, so fundamental to the machine industry that they have been called the industry's "bread and butter". They are used in all sorts of machines, but because they do their work in the shadows, most people who aren't involved in the machine industry probably hear the word and think "What's that?"
So for this, the inaugural "Bearing Column", we are going to explain the absolute basics of bearings, and provide a brief explanation of the functions they serve.
Bearings are "parts that assist objects' rotation". They support the shaft that rotates inside the machinery.
Machines that use bearings include automobiles, airplanes, electric generators and so on. They are even used in household appliances that we all use every day, such as refrigerators, vacuum cleaners and air-conditioners.
Bearings support the rotating shafts of the wheels, gears, turbines, rotors, etc. 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". At first glance, bearings may seem like simple mechanical parts, but we could not survive without bearings.
So, just what kind of role do bearings play in allowing machines to operate smoothly?
They fulfill the following two major functions.
Friction is bound to occur between the rotating shaft and the part that supports the rotation. Bearings are used between these two components.
The bearings serve to reduce friction and allow for smoother rotation. This cuts down on the amount of energy consumption. This is the single most important function of bearings.
A large amount of force is needed between the rotating shaft and the part that supports the rotation. Bearings perform the function of preventing damage from being done by this force to the part that supports the rotation, and also of maintaining the correct position of the rotating shaft.
This function of bearings is what allows us to use our machines over and over again for an extended period of time.
Let's ask ourselves just how much our daily lives are dependent on bearings. You don't normally see them so it's a bit difficult to imagine, right? Let's talk a bit about cars, since those are something we all know.
When you were a child, you probably played with an electric toy race car set at least once, right? You might remember that the bearings where the wheels were attached.
But what about real cars? Just how many bearings does a single car require?
Fig.: The main places in which bearings are used in a car
Examples: Alternators, turbochargers and the like
Examples: Steering gears, pumps and the like
Examples: Transmissions, differential gears and the like
Examples: Wheels, suspension and the like
Please click the link below for more detailed information on bearings for use in cars:
Industrial Field: Automotive page
......The correct answer is about 100!
For high-end cars, the number of bearings is more like 150!
All of these bearings play a very important role.
If a car did not have bearings,
For this reason, we would be unable to drive cars safely and comfortably without bearings.
In this way bearings are constantly working in the shadows to make our lives more comfortable.
Bearings play a crucial role in our daily lives, but it is precisely because of their importance that we must constantly strive to make them more precise and durable.
Additionally, it is vital to the development of machine technology that we continue going forward to develop bearings that can work under ever harsher and more specialized conditions.
Bearings will no doubt continue to evolve and change, and to improve our livelihoods by "making the world go round".
When choosing a bearing, you must consider several important factors. The first factor to consider is the load that the bearing can support.
There are two types of loads:
– axial load: parallel to the axis of rotation
– radial load: perpendicular to the axis
Each type of bearing is specifically designed to support an axial or radial load. Some bearings can support both loads: in this case we refer to a combined load. If you have to support a combined load, for example, we recommend that you choose a tapered roller bearing. If you need a bearing capable of withstanding a high radial load, then we recommend a cylindrical roller bearing. On the other hand, if your bearing needs to support lighter loads a ball bearing might be sufficient as they are often less expensive.
Rotation speed is another element that should be considered. Some bearings can withstand high speeds. The presence of a cage for cylindrical roller bearings and needle bearings allows for greater speeds than bearings without a cage. However, the choice of a higher speed is sometimes made at the expense of the load. You should also consider the possible presence of misalignment; some bearings are not suitable for this situation, such as double row ball bearings.
You will therefore need to pay attention to the bearing construction: insert and spherical bearings make it easy to support these misalignments. We suggest that you lean towards bearings with automatic alignment which automatically correct alignment defects caused by shaft bending or installation errors. Similarly, operating conditions are very important when choosing the ideal bearing. It is thus necessary to analyze the environment you will be using the bearing in. Your bearing may be subject to a number of contaminations. Some uses can lead to noise disturbance, impact and/or vibration.
Your bearing must therefore withstand this impact on the one hand and not be an inconvenience on the other. Another essential element to consider is the bearing life. Several factors, such as speed or repeated use, can impact the bearing life.
Choosing a sealing system is essential in order to ensure the correct and long-lasting operation of a bearing; it is therefore important to ensure that the bearing is always well-protected from any impurities and external agents, such as dust, water, corrosive fluids or even used lubricants. This choice depends on the type of lubricant, the ambient conditions (and therefore the type of contamination), the fluid pressure and the rotation speed. To give you a good place to start, the fluid pressure is a determining factor in the choice of sealing system. If the pressure is high (in the range of 2-3 bars for example) a mechanical seal is ideal. Otherwise, the choice will be directly linked to the type of lubricant, grease or oil. For example, for grease lubrication the most commonly used solutions are: deflectors or washers, narrow passages that are machined or with grooves; in the case of oil lubrication the sealing system is often accompanied by the presence of a groove for oil recovery.
Conditions of use can also influence your choice, especially when it comes to assembling the bearing. The rigidity and precision that your use requires must also be taken into account. In some cases, you can provide for the application of a preload in the assembly of your bearing to increase its rigidity. Additionally, the preload will have a positive impact on the bearing life and noise level of your system.
Be careful, in order to choose the preload (radial or axial) you must know the rigidity of all parts through software or experimentation. In your selection criteria, you must also consider the ideal material for your bearing. Bearings can be made out of metal, plastic or ceramic. The bearing material depends on its intended use. We recommend that you choose the most compression-resistant bearing. Keep in mind however that the material used affects the price of the bearing.