- Mar 23, 2020-

# How do I determine the loads on a bearing?

Matt McCormack, applications engineer for SKF gives us a little insight into what design engineers are frequently asking him. Here, he focuses on the basics of determining the loads on a bearing system.

This article was taken from a short presentation by McCormack and has been edited for length and clarity.

Often, our customers want to know how to I determine the load a bearing will encounter? Commonly, customers think of what the weight of a component is on the bearing (weight of the shaft for example) and they ignore manhy other influencing loads that are on the bearing. So when we talk about loads on the bearing, we’re talking about the reaction load at the given position.

So here we have a shaft and we have a ball bearing, and the radial load is the load that’s perpendicular to the shift. So it doesn’t matter if the shaft is going towards vertical. The radial load will always be perpendicular to the actions of the shaft. The axial load and the thrust load will be parallel to the axis. And if you ever combine those situations, then you can have both radial and axial.

As an example, here is an industrial fan. This is a very large fan to move air. A hotel has many industrial fans in it, hospitals, schools, any large building where you need to move air for heating, cooling or ventilation, you’ll find somethng like this.  The large cylinder portion is where the big fan blade is and at the top there is a box where where the buffer will be attached to this fan to move the air through it. All of this is being driven by an electric motor. The electric motor is belt driven from the fan shaft, so you have a buffer to cut between the pulley  and the belt. You can’t see it, but there’s a pulley system and a belt and then there’s two bearings supporting this fan shaft.