View Single Post
  #2   Spotlight this post!  
Unread 07-01-2011, 08:02
Jared Russell's Avatar
Jared Russell Jared Russell is offline
Taking a year (mostly) off
FRC #0254 (The Cheesy Poofs), FRC #0341 (Miss Daisy)
Team Role: Engineer
 
Join Date: Nov 2002
Rookie Year: 2001
Location: San Francisco, CA
Posts: 3,080
Jared Russell has a reputation beyond reputeJared Russell has a reputation beyond reputeJared Russell has a reputation beyond reputeJared Russell has a reputation beyond reputeJared Russell has a reputation beyond reputeJared Russell has a reputation beyond reputeJared Russell has a reputation beyond reputeJared Russell has a reputation beyond reputeJared Russell has a reputation beyond reputeJared Russell has a reputation beyond reputeJared Russell has a reputation beyond repute
Re: pic: Team 2220's Swerve Drive Module

I have some concerns about the support of the module itself. It looks like you are using a single COTS "lazy susan" type bearing. My experience is that these sorts of bearings are great when it comes to thrust loads, but they can suffer devastating failures when subjected to lots of torque loads (imagine if your robot is being pushed sideways, or if it turns at a high speed - there's a lot of torque trying to pry your bearing open). Your pivot is located at the top of the module, so the distance between it and the floor acts as a lever arm and amplifies the torque the bearing will experience. We have used this type of bearing on turrets before, and twice we have experienced devastating failures after a big hit where the bearing cracked open.

If you want to get away with a single, high pivot point, I would point you to the www.team221.com Revolution swerve module design - if you read through their product descriptions, you will find the McMaster part # of the bearing they use for module support. Better yet, you can use multiple pivot points (one high and one low) to prevent excessive torquing at the top.
Reply With Quote