Gearbox Maximum Torque

[thefro526]

Originally Posted by EricVanWyk

Some of the students prototyped a lifter mechanism that featured and subsequently destroyed a P60 132:1 gearbox. The final planetary stage was almost entirely bald.

Cou you post a picture of the damaged parts of the gearbox?

We played with a banebots P80 256:1 Gearbox for our Hanging Mechanism that was later distroyed. Apparently the motor was driven the wrong way and stalled against a stop for the arm for too long and I believe this stressed the carrier plates inside of the gearbox, but I'm not entirely sure. I'll have to crack it open next time I'm in the shop and see.

[Coach Norm]

I am the teacher/lead at 2468, the Team Eric is referring to in this post.

We have used the Banebots for three years now in a variety of applications and have had great success as well as appreciate the service we have received from them.

No information is provided by Banebots as to whether it would be able to handle the stress we placed it under.

Another mentor (physics teacher) ran through all the calculations with a group of students to decide on the FP and the Banebots P60 132:1 mentioned in the post.

The apparatus was mounted in the middle of the chassis. It was positioned within about 6 inches of the rear chassis "C" channel. We had a carbon fiber hook on the bar connected by spectacord to a spindle attached to the output shaft of the P60. The motor was mounted on a 1/4" aluminum plate that was attached to 80/20 rails.

The last output gear was stripped of the teeth in a lift. It was probably the 15 or 16 lift we had made with the system. It would lift the robot above the tunnel in less than 6 seconds.

Maybe this will help with the discussion.

Thanks,
Norman

[jspatz1]

We are often lulled into the assumption that a gearbox can handle whatever job we are applying it to for the desired speed, but with ratios this high, they can certainly self-destruct if too much motor is used. It is important not to use a motor that can yield more torque at the output than the gearbox can handle. Planetaries by their nature have very small teeth for their ratios, which is why they are so compact, but this limits their output torque compared to more robust designs. For high-ratio, low torque applications were compact size is a primary consideration, they are great. But if you are planning to push a planetary hard with a torquey motor, beware.