X-Arrangement or O-Arrangement in a linear guide?

2024-05-03

In the world of linear guides, you’ll often hear about X-arrangements and O-arrangements. These terms refer to how the ball tracks are positioned inside the rail, which in turn affects the lever arm length between the two ball rows that absorb side load moments. Basically, we’re talking about situations where you have an overhanging load that tries to twist the carriage sideways.

The amount of force a ball row can handle depends on things like the size of the balls and how many of them are involved in taking up the load—let’s call that F. The distance between the two load-bearing ball tracks is your lever arm, or "a". The moment (torque) the carriage can resist is calculated using the formula:
M = F × a

In an O-arrangement, the lever arm “a” is much longer than in an X-arrangement. That means, using the same formula, an O-configuration can absorb significantly higher moments than an X-configuration.

So, O-arranged linear guides offer better lateral stability compared to their X-shaped counterparts.

Check out the video on the topic featuring Carry Lindholm from Bosch Rexroth: