Today we will have a look on an interesting mechanical component. It’s nothing, but bearings. Do you know what is a bearing?
Well, you might be familiar with that.
If not, let’s check it out what’s that.
What are Bearings?
Here is a technical definition of bearings.
Bearings are highly engineered, precision made components that enable machinery to move at extremely high speeds and carry remarkable loads with ease and efficiency.
Looks too complicated?
Let me explain in simple terms.
Shafts usually rotate at very high speed. Sometimes, it needs to be loaded. If we apply the load directly on this shaft rotating at high speed, friction is going to build up.
Due to high friction, the shaft will wear out soon. Ultimately, it’s going to cost you.
So to avoid this, we need something. And, hence we use bearings. Their purpose is to reduce this friction.
Watch this video to get a more clear understanding of how bearings work
What are the types of load bearings take up?
Bearings can handle three types of loads. They are:
- Radial loads
- Axial loads
- Combination of radial and axial loads
Radial loads are the loads which act perpendicular to the axis of the bearing.
Whereas, axial loads act parallel to the axis of the bearing. Thrust load is another name for the axial load. I might use this name in the later part of this post.
Sometimes, the bearings might need to handle both radial and axial loads.
Typical parts of bearings:
There are three important parts in a bearing. They are:
- Outer race
- Inner race
The above image is an image of a ball bearing. Different types of bearings will have different parts.
What are the types of bearings?
So far, I talked generally as bearings. Now, let’s get into types. Here are few important types of bearings.
- Ball bearings
- Cylindrical Roller Bearings
- Needle Roller Bearings
- Tapered Roller Bearings
- Ball thrust Bearings
- Roller thrust Bearings
- Tapered Roller Bearings.
I mentioned that these are important types of bearings. There is a further subdivision of this types too. I am not covering them in this post.
- In ball bearings, the moving parts of the bearings are separated by balls
- It is suitable for lesser weight applications
- It supports axial and radial loads
- The main purpose of ball bearing is to reduce rotational friction
These ball bearings are also called as “ deep groove ball bearings “.
All ball bearings cannot have the same tolerance. Different type of applications will require different tolerances.
The tolerance classes of ball bearings are defined by Annular Bearings Engineers Committee (ABEC). Here is a detailed post about these tolerance classes.
Important applications of ball bearings:
Cylindrical roller bearings:
The cylindrical roller bearings are generally called as roller bearings.
- These bearings will have high radial load capacity
- They are suitable for high-speed applications
- They are suitable for radial loadings and not for thrust loadings.
The cylindrical roller bearings are designated like NU, NJ, NUP etc. I am not going deep into this designation.
If you are interested, you can read more about the designation of cylindrical roller bearings here.
Few important applications of cylindrical roller bearings are:
- Turbine engine main shaft
Needle roller bearings:
Needle roller bearings are almost similar to cylindrical roller bearings. These bearings have very low diameter cylinders, such that it looks like a needle.
Few important applications are:
- Planetary gears
- Constant mesh gears
Ball thrust bearings:
Ball thrust is used especially to handle thrust loads while operating at high speeds.
Here are some applications of ball thrust bearings:
- Screw jacks
- Machine tool spindle Tailstock
- Vertical openers ( Spinning and Weaving machines)
Here are few useful resources for Ball thrust bearings:
- Thrust Bearings by NSKAmericas
- Applications of Ball Thrust Bearings
Roller thrust bearings:
Radial thrust bearings can handle a large amount of thrust and radial loads.
The main difference between roller bearings and roller thrust bearings is that roller thrust bearings can handle larger thrust whereas roller bearings cannot.
The important application of roller thrust bearing is that it is used in car transmissions.
Tapered Roller bearings:
Tapered roller bearings can bear a very high amount of radial and axial loads.
It is widely used in
- Car hubs
- Crane hooks
- Swivel of drilling digs
Spherical roller bearing:
Spherical gear bearing is designed to work in the application where sphere misalignment exists. These bearings are extremely resistant to shock loads.
The following video will give you a clear idea how spherical roller bearings work.
So far, we were discussing the types. Let’s check a video, how bearings are manufactured.
Watch this youtube video on the manufacturing of ball bearing.
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