Selecting the right roller chain setup for an application is an involved process. The information given here is meant to serve as a starting point, an orientation to the main points of emphasis in the selection process.
There are two basic ways to select a roller chain, starting from two different pieces of information. One method begins with the total rated power of the application (in kW) while the other method starts with the maximum allowable load.
For either method, there are a few essential pieces of information that you need to know in order to size the application correctly.
First, determine the orientation of the application; is it a horizontal ordinary linear transmission, or is it a lifting, vertical application? This will affect some of the important load calculations.
Next, what is the power to be transmitted?
These factors will help determine the necessary diameter and speed of both the driving shaft and the driven shaft. Also, you’ll need to know the center distance, which is the distance from the center of the driving sprocket to the center of the driven sprocket.
An important figure is the so-called service factor, or Ks. This constant addresses the chain’s transmission capacity, which is affected if there is frequent load fluctuation. The appropriate service factor Ks must be applied based on the source of power and type of machine. Basically, this refers to the amount of load impact or vibration in the machine.
Next, tentatively select the chain size and number of teeth for the small sprocket. This is typically done from a table provided by the manufacturer. Likewise, determine the number of teeth for the large sprocket. This can be obtained from the speed ratio.
Lastly, determine the chain length.
This is the basic outline of the procedure involved. Individual web sites from specific manufacturers have fuller treatments of the selection process including tables and graphs that aid in the selection process.
Filed Under: Motion Control Tips
