Bearings are very important machine elements in mechanical design. There are different types of bearings that we use in different applications. Here, we explain the thrust bearings and their types of them in detail.
What is Thrust Bearing?
Thrust bearings are the types of bearing applications where the axis of rotation is perpendicular to the surface of the bearing. So, there is perpendicular friction between the surface of the bearings. In the design applications of these bearings, the lubrication characteristics are very important.
We use the bearings in the rotating shaft supports. We need to place and fix the rotating shafts to obtain a complete system. So, to fix the rotating shafts, we need a support structure that does not prevent rotational motion. And bearing applications are developed for this purpose.
As you understand from its name, they are for the thrust loads which are in the direction of the axis of rotation. So, we expect axial loading capacity from the thrust bearings.
We generally use the thrust bearings in the load applications that şs same direction wşth the shaft. If there are radial loads, the use of radial ball bearings or radial roller bearings is more common.
Types of Thrust Bearings
There are different types of thrust bearings that we use in different applications.
Fluid Film Thrust Bearings
They are a special design of thrust bearings that contain different kinds of shapes and plates of metals that are separated with the fluid films. They are very good for heavy-duty applications such as ship propellers etc.
This is the first and the most common type of thrust-bearing application. Between the contact surfaces, there are small balls. With the application of rotation, the ball starts to roll between these surfaces. So, it is possible to support the rotating shafts in the structural systems.
The most important advantage of the ball bearings is, that their need for lubrication is smaller than the conventional sliding bearing mechanisms. But, they are not supporting high axial loads.
These are the types of thrust bearings where the rotation of the bearing surfaces take place with the thin layer of fluid. This thin layer provides very low friction and supports the rotational motion. The high-pressure oil işnside these bearings is not good for high-speed applications.
Magnetic Bearing Applications
Magnetic bearing applications are the applications where the magnetic force is used to obtain the rotational motion. This is maybe the lowest drag and friction application which is for high-speed applications.
Cylindrical Thrust Roller Bearings
Instead of the balls, they use rolling cylinders between the surfaces of these bearings. The placement of the small cylinders is horşzontal in position whşch are pointing to the axis of rotation.
The main advantage of the cylindrical thrust bearings is, that they provide very good axial loading capacity that comes from shafts. But the disadvantage is, that their wear resistance is lower than the ball bearings. Also, the frictioın between the cylinders and surfaces is higher than the ball bearing because of the higher contact.
In the market, they are cheaper if we compare them with the conventional other types of bearings.
Spherical Roller Thrust Bearings
They are the spherical design of roller bearings that provides shaft misalignment and both axial and radial load supports. They are very common in applications where the movement of the shaft is not smooth.
Also, they have the greatest load-carrying capacity over the other types of thrust bearings.
Tapered Roller Thrust Bearings
They are also one of the most common types of them and the load supporting members are in the shape of taper geometries. The smaller and bigger diameters of the taper geometries are very important to obtain the required rotating action.
Also, their head section looks at the axis of rotation. This is a very important thing that you need to consider.
The most important advantage of roller thrust bearings is, that they can support both axial and radial loads at the same time. Also because of the higher contact surfaces, the total surface provides better attachment.
They are the most expensive type of thrust bearing applications. Also, they are very common in automotive applications.
Thrust Bearing Materials
Before looking at the types of materials that we use in the thrust bearing applications, we need to understand the general expectations from these systems.
The most important feature that we are expecting from these materials, is the lubrication characteristics of them must be very good. They won’t chemically react with the lubricants and they have to possess good adhesion between the materials.
And also, they must possess very good wear resistance capability. Because thrust bearing systems are the frictional systems where the wearing of the parts can take place.
Furthermore, these materials must perform well in corrosive environments. Because there are different kinds of applications that they use these thrust bearing applications.
So, these are the general materials that we use as the thrust bearing material.
Stainless steel is the most common material that we use in the load-carrying elements of the thrust bearings. For example, the balls, cylinders, or tapered cones are made from stainless steel materials.
Stainless steel is one of the hardest materials that make them suitable for dynamic applications such as bearing applications. So, their use is very common in bearing applications.
Also, high alloy stainless steels are very good in terms of wear resistance. And their applications are very common in these systems. And also with the Chromium element in the steel, they possess very good wear and rust resistance.
Ceramics are also a very important material that we use in the load-carrying elements of the these bearings. They are very hard but they have a brittle structure which has lower toughness. So, their use is not common as the stainless steel materials.
In the thrust bearing applications where there are no or little dynamic axial or radial loads, we can use ceramic materials.
Brass and Steel Materials for Cage
The cage materials for thrust bearings are generally brass and steel materials which provide important structural support for the load-carrying elements such as balls.
Brass and steel are very good elements that are worn resistant and have good lubricity properties. So, they are proper for thrust bearing applications.
Applications of Thrust Bearing in Engineering Systems
There are different kinds of applications in that they use them. These systems can find different kinds of applications that are very important for humanity.
Machinery and Industrial Systems
Industrişal systems include various kşnds of complex machinery. For example, the transmission of forces and the transmission of different loads are very important applications in industrial systems. Also, moving the loads between the different sections of the manufacturing site is another important application.
The use of thrust bearings is very common in industrial machinery to carry the loads and power between the different systems.
Mining and Construction Machinery
Like industrial applications, mining and construction machinery are also very important heavy-duty applications that use them. This is because thrust bearings are very important in load-carrying and construction applications.
Especially construction machinery is generally hydraulic and pneumatic systems and there are lots of kinds of power transmission applications between the different parts. So, the use of them is very common in these systems.
Automotive is the biggest sector that uses thrust bearing applications. At the uniting joints between the wheels and axles, the use of thrust bearings is very common. So, most of the produced thrust bearings are served by the automotive sector.
And also, the power transmission systems of automotive applications, they us thrust bearings.
Advantages and Disadvantages of Thrust Bearing Applications
Like the other machine elements, there are important advantages and disadvantages of the thrust bearing applications. A designer must consider all of these factors when he or she is using them.
- The first important advantage of the thrust bearings, they are very good to carry the axial load coming from the shaft. In most applications, axial loads can occur because of the thrust forces from other sections of machinery.
- There are various kinds of structures and shapes of thrust bearing applications. So, for nearly every bit of different application, you can find a proper one.
- They show very good performance in the high load capacity applications where the harsh use environments that we need to use. For example, the use of these systems is common in mining and construction systems because of this factor.
- Also, the assembly of these systems is very basic with other kinds of machinery. This is a general thing that you can consider.
- The most general downside of these systems, you can not use them where there are radial loads that are coming from the shaft. So in this case, you need to use the radial bearing applications.
- They add extra cost to the design system. But most of the time, their use is mandatory for power transmission with rotating shaft applications.
- They need lubrication. So, in regular lubrication applications, you need to take special care about the lubrication.
Conclusion on Thrust Bearings
As you see above, there are various kinds of applications for them. We stated the general points about these systems. So, you can use this guide to design your systems with thrust bearings.
There are various kinds of them in different constructions. The general difference between these constructions is generally because of the load carrying and working principles. They have different load-carrying capacities, some of them carry axial loads better and some of them are not. So, selecting the proper one is generally up to you.
Also, the materials are not wide range that they use in these applications. And we need hard materials to use in these applications. This is because they are highly dynamic applications where load-carrying capacities are very important. And also, wear resistance is another important phenomenon that we are expecting from thrust bearing applications.
As you see above, there are different areas where they use thrust bearing applications. And in general, these areas are heavy-duty fields such as mining and construction. This is because they are very good in load-carrying capacities.
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FAQs About Thrust Bearings
They are the systems that support the rotating shafts which are carrying load and power. And they possess a feature to allow the application of thrust loads. This is the general reason that we are saying them as thrust bearings. There are also different types of thrust bearing applications in the market. Engineers are selecting the proper one for their applications.
There are various kinds of use areas of thrust bearing applications. But in general, we use them in heavy-duty applications. This is because they are very good at the transmission of heavy loads. For example, their use in mining and construction equipment is very common.
The main difference between these two mechanical systems is you can understand from their name that the axial bearings are very good at carrying loads in axial directions. So, they have the same meanings. Because thrust load is a more field name of the technical axial loads.
In general, there are two classes of bearings which are radial and axial. Radial bearings are very good at the radial load carrying capacities. And also, axial bearings are very good at the axial load carrying capacities. So, we make the general discrimination between the bearing systems according to their load carrying capacities.