Change ratio on 28byj-48 stepper motor gearbox
Hi
The 28byj-48 normally, but not always comes with a 64:1 ratio at output shaft. I need to have a ratio of about 16 to 20:1. They look to be 0.3 approx modulus. Has anyone stripped the gearbox and rebuilt to get a different ratio. May need to change pin positions. 3 stage box, what spurs would I need to get a suitable ratio.
Thankyou
Charles Harris
2 Answers
As far as I can tell the ratio is always 64:1 (actually 63.68395:1). As you no doubt have seen, the housing is specifically manufactured for the 64:1 gearset. It will take a lot of effort to modify the gearset. As cheap as this motor is it doesn't seem like it would be worth it.
My best suggestion is to add a additional gearset on the output to bump the speed back up. A 1:3 or 1:4 ratio would give you what you want.
I am back!.. Have done what you advised and have done additional drive train. On the output of the 28BYJ-48 i have fitted a 40t drive belt which drives a 20t drivebelt, this then drives a 20t crown gear, which drives a 20t gear then a 18t gear and then the final drive is 15t (gear drives onto a rack. The gear required to go thru a right angle and then to lower gears to contact the main rack axle. Room issue underneath.
Charlie Harris
Charlie Harris 22 Mar, 2024 06:38 AM
Oops. to continue. so I have motor gear/belt and : 40t, 20t, 20t, 20t, 18t, and 15t. My 80 year old brain cant get a handle on how to calculate the overall ratio. It should be some quite less than the 64.1. Your comments would be very much appreciated. Charles
