More Torque For Lift


I’m fairly new to building and our team is having an issue finding the right amount of torque for the lift. We currently have a 1:7 gear ratio with 4 [393] motors at normal torque gearing. Our team has tried using a 1:7 gear ratio and attached motors on both sides of the shaft of the driven gear but didn’t seem to be enough. The robot is a two bar dump bot and is entirely aluminum. I was thinking of using 6 motors on the lift and trying High Speed Motors?
Our current [393] motor allocations are:

• 4 Motors for drive
-The back two drive motors have IME attachments.
• 4 Motors for the lift (Possibly want to use 6 motors instead)
• 2 Motors for the claw

What kind of gearing do your robots have for the lift and how could I get more torque on my lift?

Any help would be truly appreciated and I am very open to suggestions.
The picture of the lift is attached below. **(This picture is older the steel was replaced with aluminum.)

Simply put: rubber bands.

Our lift uses 6 high speed motors on a 5:1 gear ratio for torque. We made our arm and pneumatic claw as light as possible and took a few days to minimize friction. I haven’t tested its maximum capacity but in competitions its thrown 5+ stars without a problem. From what you described, youre using 10 motors now so adding two more to your lift, in my opinion, would be the best usage for them unless youre planning for something else. Other than that try to reduce friction as much as possible and lighten up your arm and intake as much as possible and like @Mr_L_on_Yoshi said rubber bands can help your lift immensely but make it more difficult to hang using your arm

you must have a tone of friction somewhere and your build quality must not be great. A 1:5 on 4 motors is enough to 7 or more stars. I would check to make sure every motor is working, and every shaft it seated into the motors. Also make sure that all the internals are the same one one of them are one speed, and that they are all on torque. You will also want to check to see if you are eating though the metal, if you are, you will want to change the bearing flat. You should definitely have enough torque to lift 7 stars. You should not need 6 motors.

Judging by the picture it looks like the culprit here is friction. A good practice for spacing is leaving a washer’s worth of extra space on each shaft, and use nylon/teflon washers every time you see metal on metal contact, like shaft collars against c-channel. Adding 2 more motors will help, but on a 1:7 you should be able to lift 5-6 stars without rubber bands. I would suggest going through the system and checking for bent shafts or tight spacing, then adding rubber bands and see what happens.

I would always prefer too little spacing/washers than too much. :slight_smile:

I agree with all previous replies - it is friction. @EfrainGonzalez, on your picture in OP, I couldn’t see any bearing blocks near the gears. There must be a ton of friction between square shafts and square metal holes.

The best practice is to have two bearing blocks supporting each shaft and two screws securing each bearing block. And with high torque required for the long arm you want to run the shaft through the central bearing hole.

Here is a picture of the shoulder assembly:

If you look closely at the metal around motor shaft, you could see badly damaged walls. Due to the “spacing constraints” the bearing was originally mounted with just one screw on top and motor shaft going through the bottom of the bearing. After half an hour of practice square hole started to turn into an oval and everything had to be disassembled and rebuilt anyway.

Ahh Yes I did not think about friction. Thank you for bringing that ti my attention I must have forgotten. That also may have been the issue with my past builds

Also, instead of rubber bands bungee could be a option. We have a 1:5 gear ratio with 6 high strength motors. I think it has the right balance of speed and torque. Many teams have a 1:7, so if you make adjustments like others said, I think it should have plenty of torque.

Our team solved this by having 4 motors with a 1:7 ratio and using washers everywhere to prevent metal on metal connections. We also used rubber bands to help it out.