What Are the Advantages of Using Internal Spur Gears?

30 November 2020
 Categories: Industrial & Manufacturing, Blog


Traditional external spur gears are a good option for many applications. However, there are times when it might be better to use internal gears. How do these products work and what are the benefits of using them?

What Are Internal Spur Gears?

Traditional spur gears have external teeth. These teeth sit around the gear on its outside edge. The inner part of the wheel is smooth and doesn't have any teeth; the hole in the wheel is often relatively small. As the gear wheel moves, the teeth engage with the teeth on an adjacent gear making it turn. Typically, the wheels turn in different directions.

While internal spur gears work on the same principle, their teeth are set on the inside of the gear's circle. Here, the outside of the wheel is smooth and the hole inside tends to be bigger. As these gears work, their teeth engage with the teeth of a smaller gear wheel. This wheel sits inside the main wheel rather than outside it. The wheels usually turn in the same direction here.

Why Use Internal Gears?

Having teeth on the inside of a spur gear has some benefits. You could create a system with better functionality and longevity. For example, internal spur gears often work better if you are short of space. They are typically more compact than external devices as the primary parts are contained inside the main wheel. You don't have to make room for a series of wheels here

Also, the two gears can sit closer together than they might on an external system. You won't need additional parts, such as idler gears, to compensate for the shift in directional movement. This design often makes for a stronger gear that can carry heavier load weights than external alternatives. The wheels' teeth have a bigger contact area when they mesh together. This gives their system some extra stability.

This internal placement also helps reduce wear, tear and damage to the gear teeth. Teeth work together more smoothly and evenly. Their internal position also gives them extra protection from external damage. Finally, the teeth on these wheels are less likely to cause any damage themselves as they sit inside the circle. They won't catch on anything outside the wheel or damage hands if people touch the gear when it is in motion.  

To find out more about these gears and whether they are the best solution for your application, contact a spur gear manufacturer.