How does a cycloidal gearbox work? | Structure and function simply explained | parametric equation

In this video, we will look at the structure and working principle of a cycloidal gear. A cycloidal gear is generally used for precise control of moving parts of robots.

In this type of transmission, the cycloidal disc is driven by an eccentric shaft. Fixed roller pins are arranged in a circle around the eccentric shaft into which the cycloidal disc engages. As the eccentric shaft rotates, the cycloidal disc is rotated around these pins by the eccentric motion. The cycloidal disc itself rotates around its axis of symmetry, but in the opposite direction to that of the drive shaft and at a much slower speed.

There are holes in the cycloidal disc into which the pins of a so-called load plate behind it engage. In this way, the cycloidal disc drives the pin disc. The output shaft is attached to the pin disc coaxially with the drive shaft.

The shape of the cycloidal disc is based on a cycloid. Such a cycloid is created by rolling a rolling circle on a base circle. In practice, contracted cycloids are often used to keep the imbalance low.

00:00 Structure of a cycloidal gearbox
02:03 Rolling a disc on a plane
02:26 Rolling a disc on the outside of a circle
03:19 Rolling a disc on the inside of a circle
04:12 Kinematics of the cycloidal gearbox
05:06 Transmission ratio
05:44 Use of a cycloidal disc
06:18 Cycloidal disc with ordinary cycloid
07:08 Manufacturing the cycloidal disc with a milling cutter
07:31 Cycloidal disk with contracted cycloid
08:31 Comparison of cycloidal disks with ordinary and contracted cycloids
08:46 Construction of the cycloidal disk
09:53 Determination of the rolling circle diameter
10:44 Determination of the base circle diameter
11:54 Determination of the hole diameters for the load pins
12:33 Parametric equation of the cycloidal disc
13:31 Preventing Imbalances
13:50 Advantages and disadvantages of cycloidal gears vs. planetary gears