You’re listening to the four questions with an engineer podcast, the show that brings you bearing insights from CCTY bearing. On this episode we are discussing the standard ball bearing.
Cory, why do you think that this bearing has been around for more than two hundred years and unchanged?
So, the concept of a rolling bearing has been around basically ever since the wheel was invented. Didn’t take too long for people to realize it was easier to move an object using a roller then it was just to push the object in the ground. So, it most likely started with moving large stones for buildings and people realize that using rollers to transport the heavy objects was a much more efficient way.
Then, if we go forward to the fifteen hundreds, we can see Leonardo Da Vinci sketched one of the first ball bearing sketches available and it’s basically the same exact design that’s used in the in the modern ball bearing. The issue was the material was not strong enough or reliable enough to use for ball bearings at that time. So, it wasn’t until the industrial revolution when rolling bearings are more widely used and they had the endurance to give them a use case over sliding bearings, and then the last fifty, sixty years we’ve exponentially grown manufacturing and technology to create very reliable and very useful ball bearings.
What are the benefits of ball bearings?
I’d say the main benefit of a ball bearing is less power loss and heat generation. They also beneficial to occupy short axial distances and they can be used at much higher speeds than sliding bushings can be used.
How often do these bearings need maintenance?
It really depends on the application.
Generally, whenever the grease needs to be replaced, it’s important to service the bearing and if there’s contamination it’s important to service the bearing and then obviously if you feel any looseness or tightness in the bearing, you might want to look into it.
But an interesting aspect of ball bearings is generally all the failures come from lubrication or contamination. There’s a small percentage of bearing failures that come from the installation method or the choice of the bearing and then just a fraction of percentage of bearings come from the actual material or production. So, it really shows is important with application engineers to make sure using the correct bearing because if the grease or bearing is wrong, that’s probably why you’re going to get a failure, you’re not really going to get too many failures.
If you chose the correct bearing, you chose the correct grease and you chose the correct seal, you’ll have a very small percentage of bearing failures at that point.
What are a few types of ball bearings and how do they differ from each other?
So, if we just focus in the realm of ball bearings alone, we can generally separate them into what direction the load is taking. So, the deep groove ball bearing, which is the ball bearing that comes to everyone’s head when they think of a ball bearing, is meant for primarily radio loading and then there’s axial deep groove ball bearings that are meant primarily for axial loading.
There’s also angular contact ball bearings, which take the load and angle and they’re meant for combined radial axial load. And you generally will see angular contact ball bearings as a double row because the axial direction is in both directions and so once one row takes the axle direction in one direction, in the other row can take the axle direction in the other way and then they both can take the radial to load.
There’s also a four-point contact ball bearing which is just a single row and can take an axial load in both directions. There’s contact point two on the upper raceway, outer raceway, and two on the inner raceway, and this is kind of a more compact bearing design that can take axial loading in both directions.
And then in those classifications of bearings we can separate out into many different ways as well. There’s different materials used for different applications, whether it be for temperature, for corrosion resistance, for weight, and then from there you can go with a lot of different grease choices as well, depending on the surrounding application. If it’s in a food area where it needs to have a certain type of grease, or if it’s surrounded by water. So really there’s endless different types of bearing designs when you get into that.