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

[Ricky Q.]

We are disappointed to announce that VEXpro Traction Tires will not be available for the 2013 FRC Season.

Due to unforeseen manufacturing issues, we were unable to guarantee the quality level required for VEXpro Products and FRC applications. We decided that rather release a product that does not live up to our quality demands, we would postpone this item’s release.

VEXpro Traction Wheels will still be available. We recommend using Roughtop or Wedgetop tread with them.

Customers who have placed orders for VEXpro Traction Tires are being contacted individually. Contact us with any questions at support@vexrobotics.com or 903-453-0802.

Best,
Ricky

[Ricky Q.]

Originally Posted by Joe G.

The old style traction wheels appear to have been discontinued and replaced with these.

The old IFI Wheels were discontinued as part of the VEXpro Relaunch.

Best,
Ricky

[Redo91]

Are the IFI wheels discontinued or just not part of the VEXpro line? I ask because they can still be found through a search on the site.

[Ricky Q.]

Originally Posted by Redo91

Are the IFI wheels discontinued or just not part of the VEXpro line? I ask because they can still be found through a search on the site.

They are discontinued. The search has not fully cleared out of all the old IFI Robotics items yet.

Best,
Ricky

[pfreivald]

Are the mecanum wheels still good to go?

[Richard Wallace]

Originally Posted by Ricky Q.

Due to unforeseen manufacturing issues, we were unable to guarantee the quality level required for VEXpro Products and FRC applications. We decided that rather release a product that does not live up to our quality demands, we would postpone this item’s release.

This is what good suppliers do when they have a quality problem. They let their customers know about it right away.

I wish all of the suppliers I deal with would do this. Props to IFI/VEXPro.

How much will the overall diameter of a "four inch" Versawheel be changed, relative to that of a Traction Tire, when roughtop or wedgetop conveyor belting is used instead? The renderings appear to show the Traction Tire proud of the wheel by ~3/8", so I'm guessing that traditional treads will reduce the OD by ~1/4", is that about right?

[Ricky Q.]

Originally Posted by pfreivald

Are the mecanum wheels still good to go?

Yes, all other products are still good to go.

The VEXpro elves will be very busy the first week of January getting orders shipped out to teams before kickoff.

Best,
Ricky

[pfreivald]

Originally Posted by Ricky Q.

Yes, all other products are still good to go.

The VEXpro elves will be very busy the first week of January getting orders shipped out to teams before kickoff.

Best,
Ricky

Excellent! Thank you for the quick reply.

[AllenGregoryIV]

Are there plans to sell the ball shifter mounting bracket separately?

Thank You

[topgun]

What gear ring ratio do you recommend for the mounting the 775 into the VersaPlanetary gearbox with the intention of mating it into a gearbox with two CIM motors? The CIMs are rated at 5300 rpm no load rpm. The 775 18V are rated at 19600 no load rpms. The resutling ratio is 3.679. Do we go with a 3:1 gear ring or a 4:1 gear ring?

Really love the concept of not pressing on a pinion gear. That is the most stressful part of building the robot because one small slip and you are out 5 or more days waiting for a shipment of a new motor. Also, anything to make it easier for teams without a lot of equipment to use.

Thanks.

[Mk.32]

Originally Posted by topgun

What gear ring ratio do you recommend for the mounting the 775 into the VersaPlanetary gearbox with the intention of mating it into a gearbox with two CIM motors? The CIMs are rated at 5300 rpm no load rpm. The 775 18V are rated at 19600 no load rpms. The resutling ratio is 3.679. Do we go with a 3:1 gear ring or a 4:1 gear ring?

Really love the concept of not pressing on a pinion gear. That is the most stressful part of building the robot because one small slip and you are out 5 or more days waiting for a shipment of a new motor. Also, anything to make it easier for teams without a lot of equipment to use.

Thanks.

The pinion thing is an annoying issue, but having an $30 Arbor Press + a few extra motors makes the process go a little smoother.

Also I asked this before but it seemed to have gotten buried, do you have any load tests on the VersaPlanetary? I know BB rates theirs at 35 ft-lbs.

[Paul Copioli]

topgun,

Actually, the RS775-18V when being used at 12V only has about a 13,000 RPM free speed. The free speed is proportional to driving voltage so 12/18*19,600 is ~ 13,000. Comparing that to the 5310 RPM of the CIM motor, you get 2.44:1. Matching at free speed is not necessary (as a matter of fact, I never match at free speed) as the robot never really operates at free speed. For general drive train use, 3:1 is the proper ratio to use for the RS-775. However, I have used as high as 4:1 before to try to match speeds at operating conditions.

Think of it this way, at free speed the faster motor will try to drive the slower motor so the slower motor will act as a generator (a load) on the smaller motor. Don't worry, though, as soon as some load gets on the system, the lower power motor will slow down much faster and the speeds will be matched. Dr. Joe Johnson posted about this several years ago. I printed out that post and still have it for reference as he explains it much better than I explain it.

So the short answer is use 3:1.

Mk.32,

I have conducted all of the testing on the VersaPlanetary Gearboxes and have made my final load rating conclusions. I am currently putting it in a format more useable for FRC teams. Included in the ratings will be rated continuous torque, Max Torque, overhung load equations (aka force on the shaft), and recommended motor / gear ratio combination ratings.

However, I will share some of the data here. Please note that something will break at the Maximum tourque rating:

All ratings are based on the output torque and the gear stage at the output.

3:1, 4:1, 5:1 gear stage maximum output load rating with 1/2" Hex Shaft = 160 N-m [~120ft-lb]
The failure mode is the actual Hex Ultimate stress failure.

10:1 gear stage maximum output load rating with 1/2" Hex Shaft = 100 N-m [~74ft-lb]
The failure mode is the carrier plate stress crack originating from the mating internal spline connection. The 10:1 stage carrier pins are very close to the internal spline. This could not be avoided, but the 10:1 is above our estimated maximum Torque.

So if you are using a 50:1 double reduction gearbox, then I suggest you put the 5:1 stage on the output.

For those of you doing the math yourselves, the 100:1 gearbox with a RS775 has an output stall torque of around 58 ft-lb so it is below the max torque rating of the gearbox.

We will have a ratings table for our recommended combinations and potential failure modes for motor / ratio combinations up to 1000:1.

Paul

[AllenGregoryIV]

Paul,

If you were to use the versaplanetary with the CIM motor output shaft into another gearbox, for example the 7:1 single speed gearbox. Then the torque rating of the final gearbox would be more important correct.

For example could you use a 700:1 reduction by having a 100:1 versaplanetary into a 7:1 single speed to drive an arm. I'm thinking of an application similar to the hip joint gearbox on 148's 2011 Raptor.

[Paul Copioli]

Allen,

The rating of the VersaPlanetary only really cares about what output it sees. Your question pertains to the output torque rating of the single speed gearbox, which I am not on the hook for calculating (well, at least not yet).

The problem with your specific example is the torque rating of the 8mm aluminum output shaft and 2mm keyway combination. The load rating for the VP 8mm shaft option will be significantly lower than the 1/2" hex rating. Those numbers will be on our web site soon.

Paul

[Madison]

I have a brief question that isn't really relevant given the delay in availability of the traction tires.

On the recent EWCP podcast, John talked a bit about trying different tread profiles and how he was surprised by the effectiveness of the 'W' pattern that's available on the VersaWheel. Why, then, do the traction tires available for the traction wheels have a different pattern and can you say which performs better than the other?