Universal Rotor Log
Resources
Team
Aaron Makaruk - aaronmakaruk@gmail.com
Joshua Bond (JB) - prodigyresources@gmail.com
Problem Statement
Collaboration Spaces
Logs
October 9, 2012
I'm out all day this week until Friday. I'll try to throw a video together with some ideas. I think the first step is to get Marcin to confirm his decision & the reason for it, which i wrote about on the Wiki, about using the extra shaft and bearings even though they aren't needed. I want to be sure he understands that the bearings in the wheel motors like you are using in the lifetrac now are stronger then the old motors he was using which weren't wheel motors. The old motors couldn't support the weight of LifeTrac, the new ones can depending on which model they are. If it was up to me, i would say don't use the extra shaft and bearings for LOTs of reasons. Especially considering building a Hydraulic Motor from scratch is to be part of the GVCS 50 so it can be made to whatever specifications needed.
Here is the decision as i posted on the wiki: http://opensourceecology.org/wiki/Universal_Rotor
1) Wheel Motors(bearings built in) or Jack Shaft(with auxiliary bearing support structure)?
Due to the wide range of applications, the UR needs to handle high axial and radial forces. Wheel motors have larger bearings then standard hydraulic motors to resist these much higher forces. Wheel motors are available to handle the loads of all current GVCS applications. However wheel motors are low speed. High speed motors don't have such large bearings. While generally you don't need large bearings while doing high speed operations, an accident, such as hitting a tree stump with a high speed mower blade may damage a motor with smaller bearings. Adding a separate shaft(jack shaft) that is supported by separate bearings between the motor shaft and tool effectively isolates the motor shaft and bearings from any radial forces, as well as axial forces if properly designed. This is the design currently being used on LifeTrac III and the MultiAuger. The current design is excessive in length and has some proven and suspected issues. A much shorter and simpler jack shaft setup should be possible that is more comparable to a wheel motor. If a jack shaft setup is chosen as the primary UR setup, it should be designed so that a wheel motor can be used instead with minimal variation(or none) for replicators who choose to do so.
Heavy Duty Wheel Motor Example: 45.6 cu in White DT series 3000psi 150rpm 30gpm $279 Handles 20,000lbs of radial load. http://www.surpluscenter.com/item.asp?item=9-7703
Comparison: Wheel Motor UR Advantages: -Much more compact, lightweight, cheaper and very quick to build -Sealed & lubricated bearings -Industry Proven -Less parts to break or wear out
Auxiliary Bearing UR Advantages: -Can remove the motor with out disconnecting the tool(or the tire when used as wheel drive) -More motor choices (especially rpm) -Can use a gear reduction or multiple motors much easier
Thanks,
Josh Bond
October 8, 2012
- Universal Rotor Log page created
October 5, 2012
- JB annotated an image from the Universal Rotor wiki page.
- I'm missing something. So why not just a single square tube receiver that an implement/attachment with a square tube mount can slide into? Then you pull it out, rotate it 90 and stick it back in (I.E. mower to trencher). Just like on a trailer hitch, just bigger tube, and don't reverse it. Make the receiver the outer tube. And make it so you can add any style adapter in there you might need: extension tubes, right angle tubes, swivel tubes, adjustable angle tubes.