Machine Parts

How To Size Planetary Reducer

In my previous posts, I said that I will explain the planetary reducer selection, later.As you know, planetary gearboxes have many types produced according to need.Helical gear planetary reducers can be used for precise positioning and low operating noise, and straight gear planetary reducers can be used for standard applications.Of course, these definition classifies reducers very simply. Because there are dozens of subspecies according to their use.For this article, let’s assume that we know the output torque, the speed of the system and the need for positioning precision.

We made the calculation for the system with Yaskawa SigmaJunmaSizer + and let’s assume that the system needs i:7 ratioand the maximum torque required by the system is 67Nm ( servo output 6,57Nm).

Machine Parts

Introduction of Planetary Reducer

Planetary reducers are used for applications where low reduction rate and precision are required.Except for the general reducer definition, let’s get to know planetary reducer in a little detail.

Planetary Reducer Input Side and Output Side

planet reducer input output

When viewed from the outside, the input side for the servo motor connection and the output side for the load connection are visible.

The input side of the reducer is designed according to the shaft output and flange dimensions of the servo motor to be connected.

In general, there are body sizes such as 40, 50, 60, 70, 80, 90, 100, 110, 120, 140 and 155. However, for now, we will proceed based on the body of 90 (in the image).

Internal Structure of Planetary Reducer

planet reducer internal structure input output

Planetary reducer consists of 3 basic parts as sun, planets and ring. The servo motor drives the sun, the planets around the sun spin in the ring. In this case, the sun gear transfers the power from 3 different points (for the 3-element reducer) to the outer planetary gears.The output power increases according to the ratio between the outer ring and the sun. At the same time, the speed decreases at the same gear ratio.