Mechanisms

Mechanisms are important in many aspects of modern life. They adjust the focus on your smart phone camera, put the wheels down when a plane is coming in to land, allows automobiles, trains, trucks and ships to move and even allow probes to roam about on the surface of Mars.

So I was very surprised to learn that a newly developed rotary gear mechanism, or transmission,  is the first major new gear design since 1957!

Abacus Gears

Lets cut straight to the chase and I’ll then back fill details later on.

Abacus Gear Mechanism

The Abacus Gear Mechanism uses a series of rolling elements that move through a series of shaped channels that changes the rolling radius as the mechanism rotates. The results is a gear ratio between the inner driving hub and the out rotating hub. Sound complicated?

I guess this is why it has taken over 60 years to come up with the revolution. However there are some serious pluses. The contact points are all pure rolling elements unlike conventional gear teeth where some sliding motion (causing to wear) is involved. This should lead to improved gear life. It also has no backlash. This is ideal for robotics where backlash (the loss of motion when changing rotational direction on a gear due to clearances) is a big problem for keeping a precise knowledge of the position of the object under motion (a pickup arm for instance). And the rolling elements and the channels they roll in can be adjusted in shape. So although the first version, named “Abacus” because the shape of the rolling elements resembled the beads on an Abacus, had one shape of rolling element, the invention is not limited to that and the elements could be spheres.

And all of the above leads to another major benefit. It is significantly more efficient than the Harmonic Drive which was invented in 1957 and is the leading contended for robotics gears today.

There is a detailed article including a video on IEEE Spectrum at Abacus – First New Rotary Transmission in 50 Years.

The Harmonic Drive

Here is an animation of the Harmonic Drive.

Harmonic Drive in motion

This is pretty cool as a drive concept and also has no backlash.

Mechanical Gear Fundamentals

If you to know a little more about gears and the wide variety of uses they are put to, check out this video.

Successful Endeavours specialise in Electronics Design and Embedded Software Development, focusing on products that are intended to be Made In Australia. Ray Keefe has developed market leading electronics products in Australia for more than 30 years. This post is Copyright © 2016 Successful Endeavours Pty Ltd.