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-   -   VEX Robotics Relaunches VEXpro Product Line with over 120 New & Improved Products (http://www.chiefdelphi.com/forums/showthread.php?t=109868)

M. Mellott 10-12-2012 13:17

Re: VEX Robotics Relaunches VEXpro Product Line with over 120 New & Improved Products
 
Bumping this post/question...

Quote:

Originally Posted by M. Mellott (Post 1199582)
Love the new product lines, especially the VersaPlanetary Gearboxes! Do these gearboxes require any grease/lubricant, and if so, is it already applied to the gearbox when we receive it? I didn't see this mentioned in the product description, so I wanted to be sure.

Many thanks and much success on this new venture!


Andy Baker 10-12-2012 13:42

Re: VEX Robotics Relaunches VEXpro Product Line with over 120 New & Improved Products
 
Quote:

Originally Posted by Paul Copioli (Post 1200331)
We initially intended that the hex would be timed to a certain VersaHub feature, but we quickly realized that we could not meet our pricing targets with such a requirement so we relaxed the requirement.

Paul

For those folks who need this alignment requirement, the hubs at AndyMark meet this need. Previously, our hubs did not align with the holes, but they do now. I pulled 19 off of our shelf and put them on a Cross Hex Tube. These are in stock now:



Sincerely,
Andy Baker

AllenGregoryIV 10-12-2012 13:51

Re: VEX Robotics Relaunches VEXpro Product Line with over 120 New & Improved Products
 
JVN or Paul, can you explain how the VersaPlanetary motor connectors work? I've looked through the CAD and I see the set screw, the collar type thing with the slit and the place that it goes. My real question, "is the setscrew the only thing keeping the motor engaged?" I do like the access holes for the setscrew, and that you can swap motors with out removing the gearbox from the robot.

I'm excited to get VEXpro parts in.

JVN 10-12-2012 14:24

Re: VEX Robotics Relaunches VEXpro Product Line with over 120 New & Improved Products
 
Quote:

Originally Posted by Kevin Kolodziej (Post 1200020)
I think others and you have fleshed out most of the ideas behind this, but I do still have a few questions about longevity of the mecanum wheels. Are the rollers molded directly to the axle? What material is that axle? I expect it will be able to handle normal driving conditions just fine but what about after 3 or 4 competitions...can rollers be replaced? More importantly, can an axle be replaced if it is bent? The body and spokes of the wheel does not concern me at all. We've had bent and bound rollers before but they were easily replaced.

Hi Kevin,
The axle is 5mm #45 steel. If you check out the CAD model, you can see how the axle is supported much further out than you might expect due to some creative design of the cast aluminum roller support; the bending moment on these axles is greatly reduced. We experimented with this geometry when designing the Mecanum Wheels for the VEX Robotics Design System, and liked it so much we carried it forward to the VEXpro line.



The rollers will be made from rubber co-molded onto a plastic shell. The shaft is knurled on each end and press-fit into two of these plastic shells. We will offer a replacement roller-assembly pack which includes some TBD quantity of roller-axle-bracket assemblies.



Yes, we expect it to handle 3-4 competitions "no problem." Yes, we will provide a mechanism to replace the rollers if you want fresh ones.

Does that answer your question somewhat? I will have quantitative load ratings for you sometime in the coming weeks.

-John

JVN 10-12-2012 15:33

Re: VEX Robotics Relaunches VEXpro Product Line with over 120 New & Improved Products
 
Quote:

Originally Posted by M. Mellott (Post 1199582)
Love the new product lines, especially the VersaPlanetary Gearboxes! Do these gearboxes require any grease/lubricant, and if so, is it already applied to the gearbox when we receive it?

Mike,
For our gearboxes with aluminum gears, the teflon infused ceramic coating greatly increases the wear resistance of the gears. That said, teams should probably apply a light coating of white lithium grease to ensure longevity. We know many of you will want to be able to use these items for many years, and this will help make that possible.

The VersaPlanetary gearboxes use high-strength hardened steel gears.

At this time, we are not planning to grease the gears before shipping.

-John

billbo911 10-12-2012 16:21

Re: VEX Robotics Relaunches VEXpro Product Line with over 120 New & Improved Products
 
John,
With the addition of all these great new gearing options, is it possible you might want to make a newer version of your "JVN-DesignCalc.xls" that is defaulted with the "Ball Shifter" specs?
I know I can work with the current version by dropping in the numbers, but having the default already have the basics in there would make things even better, IMHO.

ksafin 10-12-2012 19:59

Re: VEX Robotics Relaunches VEXpro Product Line with over 120 New & Improved Products
 
Hey, I have a quick inquiry about the Mecanum wheels..

I read on the description that they're optimized for the FRC carpet. This is good and all, but how do they fare on other surfaces, like concrete? We like to demo our robots in the courtyard of our school, which is concrete.

I'm just concerned that the rubber rollers may not fare too well, and I'd love to know before I put in my order.

Thanks!

Paul Copioli 10-12-2012 20:30

Re: VEX Robotics Relaunches VEXpro Product Line with over 120 New & Improved Products
 
Quote:

Originally Posted by AllenGregoryIV (Post 1200508)
JVN or Paul, can you explain how the VersaPlanetary motor connectors work? I've looked through the CAD and I see the set screw, the collar type thing with the slit and the place that it goes. My real question, "is the setscrew the only thing keeping the motor engaged?" I do like the access holes for the setscrew, and that you can swap motors with out removing the gearbox from the robot.

I'm excited to get VEXpro parts in.


Allen,

The motor connection that the VP uses is one of the more counter intuitive engineered items I have come across in my time as an engineer. This technology is used on industrial robotic gear boxes all over the world and is becoming the common adapter for high rigidity, low backlash applications.

There are two basic principles at work:

(1) The motor pilot is not used, but the shaft is actually used as the pilot.

(2) The set screw really isn't used as normal set screw (clamping on a rigid shaft). It is used as a clamping lever to squeeze the C-coupling into an ellipse.

The C-coupler (collar type thing with the slit) and the input collar (the thing the C-coupler fits into are precision machined for an exact slight clearance. In addition, you use a specific C-coupler based on the motor shaft diameter. There is a different coupler for 3mm, 1/8", 1/8" with knurl, and 5mm shafts all with the same OD so they fit in the input collar. The clamping screw is tightened (don't really need that much tightening torque) and turns the C-coupler into an ellipse which locks it in place with no backlash. I have accidentally hand tightened a coupler before and it still locks solid. It took me over 9 months of rigorous testing when I was at FANUC to approve this technology for use on our robots, but after the testing I was sold. easy for replacing bad motors, easy for replacing the gear sets, and no more press fitting gears on motor shafts.

Now for high end motors like industrial robots use, this next benefit really isn't a benefit, but for some of the less expensive, non-high tolerance motors we use in FRC, I have found that this next benefit is really helpful:

Since you do not have to completely clamp the motor face to the VP mounting face, any shaft runnout misalignment between the motor shaft and motor mounting face is completely mitigated by just hand tightening the mounting motor plate mounting screws. Since the screws only act to keep the motor case from spinning, they only need a little loctite and hand tightening.

We will have detailed diagrams on how this all works prior to kickoff.

Paul

ksafin 10-12-2012 21:41

Re: VEX Robotics Relaunches VEXpro Product Line with over 120 New & Improved Products
 
Was the question of belt sprockets w/ VersaHubs already addressed? We want to use belts this year, how would this work with VersaHubs?

Aren_Hill 10-12-2012 21:48

Re: VEX Robotics Relaunches VEXpro Product Line with over 120 New & Improved Products
 
Quote:

Originally Posted by ksafin (Post 1200754)
Was the question of belt sprockets w/ VersaHubs already addressed? We want to use belts this year, how would this work with VersaHubs?

All of the CAD models are available, if I end up using pulleys with them for any reason I will just be machining the versahub pattern into my own pulleys. But I've got CNC access.

With a lathe you could bore out a pulley to fit over one of the versahub bosses and put a bolt pattern in it if you just have access to manual machines.

JB987 10-12-2012 21:49

Re: VEX Robotics Relaunches VEXpro Product Line with over 120 New & Improved Products
 
Quote:

Originally Posted by ksafin (Post 1200754)
Was the question of belt sprockets w/ VersaHubs already addressed? We want to use belts this year, how would this work with VersaHubs?

If you are using a live axle and hex or key the sprocket depending on use of keyed shaft or hex shaft, you wouldn't have to worry about attaching the sprockets...a dead axle set up can be done but the alignment and placement of mounting holes needed to modify a sprocket can be challenging.

Kevin Kolodziej 11-12-2012 00:37

Re: VEX Robotics Relaunches VEXpro Product Line with over 120 New & Improved Products
 
Quote:

Originally Posted by JVN (Post 1200516)
Does that answer your question somewhat? I will have quantitative load ratings for you sometime in the coming weeks.

-John

John,

Consider my questions answered! Thanks for all the detailed information. I did pick around the CAD file a little bit, but I wasn't quite sure what all was what. Now I just have to convince the team that mecanums aren't as bad as everyone says they are (you'd think our track record with them would be enough...but no) :D

AllenGregoryIV 11-12-2012 01:39

Re: VEX Robotics Relaunches VEXpro Product Line with over 120 New & Improved Products
 
Quote:

Originally Posted by Paul Copioli (Post 1200707)
Allen,

The motor connection that the VP uses is one of the more counter intuitive engineered items I have come across in my time as an engineer. This technology is used on industrial robotic gear boxes all over the world and is becoming the common adapter for high rigidity, low backlash applications.
...
Paul

Thanks for the explanation Paul, That's how I sort of thought it worked and I figured you guys knew something (a lot of things) I didn't. It seems like the perfect solution for FRC robots and it should make it so much easier for teams. My need for an arbor press in the pits just halved. The wheel bearings aren't press fits, right? I might be completely done with the arbor press if that's true.

Paul Copioli 11-12-2012 02:33

Re: VEX Robotics Relaunches VEXpro Product Line with over 120 New & Improved Products
 
Wheel bearings are not press fits. They are light transition fits, where if the bearing is at its largest and the wheel is at its smallest you may have to press it in by hand.

The tolerances are such that the worst case is a 0.0005" interference. The way the plastic geometry is designed will allow even this interference case to be hand pressed.

Tristan Lall 11-12-2012 05:21

Re: VEX Robotics Relaunches VEXpro Product Line with over 120 New & Improved Products
 
Quote:

Originally Posted by Paul Copioli (Post 1200707)
Since you do not have to completely clamp the motor face to the VP mounting face, any shaft runnout misalignment between the motor shaft and motor mounting face is completely mitigated by just hand tightening the mounting motor plate mounting screws. Since the screws only act to keep the motor case from spinning, they only need a little loctite and hand tightening.

Am I understanding correctly that the motor is essentially floating, and any shaft runout is taken up by the flexure of the motor shaft, the play in the bearing and the play in the spline?

(And it works fine without a fancy spherical-race bearing, because the runout is so small?)


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