Universal Rotor Log
Contents
Resources
Team
Aaron Makaruk - aaronmakaruk@gmail.com
Joshua(JB) - "LoadTest"
Problem Statement
Solution Responses
Collaboration Spaces
Logs
November 5, 2012
I(LoadTest) traveled to SEMA/AAPEX show to get some more ideas. Looking into the possibility of adopting components from tie-rod hydraulic cylinders as standardized by the NFPA(National Fluid Power Association). These same components(tube, caps, mounts, rods, pistons, etc) could be used to not just build the universal rotor but also, OSE hydraulic&electric pumps/motors, hydraulic hose crimpers and much more. Also discovered universal rotor work at: Modular_Vehicles that is useful. Per conversation w/marcin: -Looking for axial load capacity of standard ball bearing flange blocks(tapered roller bearing flange blocks are too expensive)
-Trying to determine if exsisting 15,000_Inch_Pound_Motor are sufficient to survive for direct wheel connection on lifetrack(no extra support bearings/shaft)
-Marcin wants to upgrade to 3" shaft, I'm encouraging him to consider using readily available higher grade steel shafting instead as this is industry proven and less suseptible to fatique then plain mild steel. But I will continue to research the availability of this material around the world and GVCS wisdom for both options.
November 3, 2012
Hi guys, Sorry i've been out of the loop, my harddrive got zapped at the airport. I had the opportunity to(scramble) go to SEMA & AAPEX last minute to get some ideas and hopefully generate some resources for an open source truck. Its the world premier automotive parts tradeshow, about 5million square feet. SEMA is like “Las Vegas”, over-indulgent and disgusting, but its was also a reminder that theres a lot of creative people out there with lots of time and ambition and also loads of money to fund ridiculousness- its just a matter of engaging them in something more practical(OSE) . However, AAPEX was a chance to get my hands on a lot of basic parts(like bearings), mostly from Asian manufacturers trying to capitalize off of the indulgence of the American automotive industry. I guess AAPEX was more like the enormous “working class” in vegas, mostly immigrants and minorities, that are trapped in dead-end service jobs, living in old motels that have been converted into apartments around the newer fancy ones. What a broken system and a testament for OSE!
One revelation from my trip: The NFPA(national fluid power association) has set standards to make tie rod hydraulic and air cylinders interchangeable between manufacturers. Looking at the components of a tie-rod cylinder, I think we can leverage these as GVCS “Legos”. With the same components as you'd use in a hydraulic cylinder, you can also use to make much of: -Hydraulic/fluid/air Motors & Pumps (vane type: http://www.pumpschool.com/principles/vane_ani.asp) -Electric motor -Hose Crimper -Universal Rotor -Lots of parts for the rest the GVCS
In other words can the tube, shaft and endcaps off a large hydraulic cylinder(ceb-press size) also be used for a motor's tube, shaft, endcaps, etc. It could save a ton of machining and make the GVCS more accessible/attainable to anyone. The air cylinders are aluminum, so that provides more flexibility. I'm going to check and see if the tubing sourced from hydraulic cylinder suppliers like (baileynet.com) has adequate tolerances to accept bearings(for motors/rotors) without further machining. Then these could be bolt together quick GVCS advancements We'll have to figure out what dimensions/parts NFPA regulates and a good source for the full line of NFPA components cheap without buying the whole cylinders. Here is Eaton's NFPA product line: http://www.eaton.com/ecm/idcplg?IdcService=GET_FILE&allowInterrupt=1&RevisionSelectionMethod=LatestReleased&Rendition=Primary&dDocName=DEV_216614 (4.9mb) I'm staying for FABTECH which is the 12-14th. If anyone there has a chance to come out it will be a good chance to see a ton of fabrication equipment. You can stay in my room. http://www.fabtechexpo.com From Joe Justice when I asked about building one of their cars to use at FeF/GVCS: Josh- that would be epicaly awesome! We are all for our cars out there and being used, ESPECIALLY by groups that are doing awesome like OSE! I'd like to help, maybe we can provide the tires/wheels or something at the very least? Please plug WIKISPEED :D And I hope you have an awesome time at SEMA! The last time I was there was 2010- and in many ways it blew my mind!
MARCIN: Can you find out the rated axial load rating for one of these bearings? The bearings are made by Fitbearings.com as a knockoff of american brands-they were here at the show. They said its not rated for any axial loading and they couldn't provide any data for such. I'll keep looking for data from other MFG's. Do you want me to look further into mounting the lifetrac tires directly to the hubs on the wheel motors that you have or are you opposed to that? I'm not sure which motors you have. You don't have the ones pictured on the wiki:http://opensourceecology.org/wiki/15,000_Inch_Pound_Motor ($279) These 712s have larger necks. From your videos it looks like you got the 701s with the smaller necks: ($400) http://www.surpluscenter.com/item.asp?item=9-9339&catname= Or did you buy the $300 ones and they shipped you the $400 ones, which commonly happens at surpluscenter.
October 26, 2012
I'm looking at 100's of designs. Theres not many universal products, and even the mfg's are pretty application specific and don't have a varied product line, but this is the general direction it is going:
Look at this product range on the 3rd page: http://www.omnigear.com/EBHQR.pdf The first two for spinning big mower blades, The WN-06 and SN-06 are wheel drives. They also make similar auger drives. Look at MDH-45 in the middle.
-This company only sells to the big tractor mfgs in large quantities so its a slow dance to get them to give me any engineering data.
But look at this one: http://www.zero-max.com/documents/Zero-Max_OHLA.pdf (5.6mb) For example: The 1st pic i've attached is the big one at the bottom has a 3.5" shaft but its only about 7" deep + the shaft.
The design will be easy to build with any kind of bearings and little machining and more "quick attach" mounting options.
RE:(With a 3" shaft Modular Wheel Unit, I can see converting the Wheel Unit to a lathe as one of the functions of the Universal Rotor concept) 3" is getting up there. You might also want to talk to your steel supplier about what stronger shaft options are available other then just plain steel. They should have something. If not http://www.metalbythefoot.com/ in Kansas City has 1144 and 4140. And Speedymetals.com and onlinemetals.com have 8620. I'm not an expert, but the material is much stronger, and later on you can make it even stronger/harder with the GVCS induction furnace(or even the wood stove)
Some of those big 20,000lb farm tractors are bouncing around on only 3" shafts. They have 200hp, 5 or 6 foot dual wheels(shaft breaking leverage) and pick up 10,000lbs on the front and back. But they aren't using mild steel.
The way the bearings are supported on the LifeTrac Wheel connect you have the shaft supporting not just the torsional loads(motor power) but also the radial and axial forces from the weight of the vehicle and ramming into things with the loader - it gets really nasty. Thats why all trucks 1-ton+ and lots of machines use a "Full-Floating" design where there is a separate wheel hub to carry the radial and axial and then they get buy with tiny shafts that "float". (see attached pic 2&3) I'm still researching, but i don't think we will do a full float design for the Universal Rotor because it takes more machining, complexity and space. But we can lessen the severity of the semi-float design consequences you're dealing with now.
RE:( Eventually, we will integrate the electric motors, but we'd like to opensource them first. Any leads to electric motor designers?)
Thats pretty hardcore. It might slow GVCS progress down- but hell, more power to ya! The only motor designers i know are working on electric car motors and are very expensive. I'll ask around, if you've narrowed down what type of motors are best for GVCS let me know, otherwise i'll stir up the wiki.
- Josh
October 16, 2012
LoadTest Posted a 2 part video response to the problem statement video filmed at FeF "Quick Attach Plate and Universal Rotor". The first part is an overview of the design considerations. The 2nd part poses the first design decision and that is to eliminate the auxiliary shaft bearing support structure from the design and rely instead on the hydraulic motor's internal bearings to support the system, with the option of adding in an extra bearing support system only when a hydraulic motor with inadequate bearings is to be used. LoadTest requests Aaron and Marcin to watch the response videos and confer with the decision before he continues further design work. Part 1: [1] Part 2: [2]
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 commercially that will handle the radial and axial loads of all current GVCS applications. However wheel motors are low speed. High speed motors don't usually 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 on the LifeTrac 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 in size. If a jack shaft setup is chosen as the primary UR setup, it should be designed so that only wheel motor can be used instead with minimal variation(or none) for replicators who choose to do so.
The current quick connect wheel assembly with the jack shaft and auxilary bearings was a necessary component when the LifeTrac was powered by the original weaker drive motors. However during the redesign, new 15,000 Inch Pound Motors were purchased which are actually wheel motors that have a much higher carrying capicity which means the whole jack shaft assembly might not even be necessary as the motor is designed to handle up to 11,000 of radial load per the specs provided by the manufacturer. It has already been proposed by Marcin that the wheel connect be redesigned to address several issues, but in reality, it can actually be completely ommited without having to purchase additional motors.
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,
JB
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.
