Ball bearings – How they are made and what are they used for

ball bearingsBall bearings reduce support radial and axial loads and reduce rotational friction. How do they manage to achieve this? Well, ball bearings use at least two races that contain balls. Thus, the loads are transmitted through the balls. Far too much? Let’s start from the beginning.

Ever since man began to move things, he made his job easier by using round rollers. Of course, the first rollers were big and barely functional but, it somehow made it easier. But, dragging things across the ground is not quite easy, the human mind had to think of something else. That’s how we got ourselves to riding bicycles and driving cars.

Ball bearings are just one type of the many kinds of rolling bearings and they have a specific function. The rollings part in ball bearings are, as we already mentioned, the balls. These little things roll between the outer and the inner ring. Those particular places, where the balls roll, are called races. The cage holds the balls in place, keeping them evenly spaced around the races.

Ball bearings – How they are made and what are they used for

ball bearingsNeedless to say, this are just the essential parts of the ball bearings. In addition, there are a lot of optional parts as well, like screws or seals but, we won’t worry about the fancy extras here.

What’s really important is to know that all ball bearings are made of steel. The reason is simple : a ball bearing has to stand up to a lot of stress and it needs to be firm. There is a standard industry classification for the steel in the bearings and it is 52100. This means that it has one percent carbon and one percent chromium. With heat treating, the steel can become really tough and hard. When rusting is a potential problem, we made the bearings from 440C stainless steel.

Traditionally ,the cage is made of thin steel. However, there are some bearings that use molded plastic cages – they cause less friction and cost less.

The life of a bearing depends on its operating speed and the load it carries. The industry standard lifespan is inversely proportional to the bearing load cubed. Naturally, there are other factors that need to be taken into consideration.

This is how they are made: