VEXPro 2014 Product Initial Impressions

[Ricky Q.]

Originally Posted by sanddrag

Seconded. Call me lazy, but I visited the product page, didn't see a ratio, moved on to something else, and never looked back. It should have the ratio on the product page.

The CIM-ile ratios are now posted and it is also back In Stock.

Ratio with RS-550: 9:29
Ratio with RS-775: 12:29

Best,
Ricky

[Paul Copioli]

Originally Posted by Ricky Q.

The CIM-ile ratios are now posted and it is also back In Stock.

Ratio with RS-550: 9:29
Ratio with RS-775: 12:29

Best,
Ricky

For those of you that use the other notation (like me), these are speed reducing, torque increasing gearboxes designed to make the motors "match" a CIM motor both physically and speed characteristics.

[topgun]

Can we sandwich a 4" VersaWheel between two HTD pulleys set up for 15mm belts, similar to what is done with the center wheel in the KOP drivetrain?

Essentially it will be pulley-wheel-pulley.

We don't need a versahub in between, correct? Also, what size of #8 bolts do we need? The max on the Vexpro site is 2". This looks like it would be longer.

Thanks.

[cbale2000]

Originally Posted by Paul Copioli

... Did you even think that some people may not want the cylinder? This cylinder is $40 and is an unnecessary expense if you already have it. We clearly put on our web site that it was not included. With that said, there was a period during the inventory transition that our web site stated the ball shifters included the cylinder, because we included it last year. Customers that ordered at that time (during the order period for the old 2 CIM Ball Shifter) that have contacted us were sent the cylinders free of charge.

Paul, is the option of getting the cylinders still open? My team ordered a pair of 2-CIM ball shifters back in December when the website still said they came with cylinders, by the time they got to us though, the website had changed to say they did not, so we figured it had been a typo and did not pursue it further at the time.


Now, getting back to the subject of this thread, I will add a few thoughts...

This is our first year buying VEXPro products (aside from speed controllers); we started with a pair of 2 CIM Ball Shifters we ordered in December, and after being impressed with their quality and ease of assembly, we went on to purchase a pair of 3-CIM Ball shifters, 14 4" Traction Wheels, 24 50-tooth Gears and some Hex Shaft (all of which we plan to use to drive this). Here's my personal opinions on each:

3-CIM Ball Shifters
Pros:

• Lighter than alternative gearboxes
• Seems to drive smoother than gearboxes we've used in the past
• Small profile, given the whats in them.

Cons:

• The assembly instructions were a little more confusing than the 2-CIM Ball Shifters.
• The gearboxes seemed to have been shipped with the wrong size (too long) screws, which stick out through the hex (spacers?) too far and prevents the faceplate from being screwed on tightly. In our case our mounting system worked around this issue so its not a problem for us on our robot this year.
• It would be nice if the 3rd stage versions came with an extra set of hex shaft spacers to allow for face mounting the gearbox while being supported from all 4 corners (We ended up making our own spacers out of AM Churro tube, which works fairly well).
• It was not immediately clear how to properly mount the CIM gears to the motors and the instructions did not cover this step, the gears also appeared to not come with all the hardware to do so (of course this is based on how we're used to mounting motors on AM gearboxes, so we could just be doing it wrong).

4" Traction Wheels
Pros:

• Super Light, less than half of the weight of our previous custom aluminum gears of the same size.
• Very easy to assemble.

Cons:

• Mounting tread with rivets was a bit tricky since you have to use long rivets that also have wide enough heads to hold the tread on. We ended up having to use long rivets with small heads and using washers to keep the tread on. Some instructions on recommended tread installation methods and rivet sizes would be helpful in the future.

50-Tooth Gears w/ VersaKeys
Pros:

• They're so freaking light!
• The versa keys were great for mounting the gears onto the wheels (using VersaHubs). The alignment looks great.

Cons:

• A few of the gears had a hard time fitting onto the VersaHubs (not sure if this was a problem with the hubs or the gears though).
• I'm not sure if they just weren't available yet when we ordered the gears or if we were just looking in the wrong place, but in retrospect it would have been better if we had ordered some of the gears with 1.125" bearing holes instead of hex.

Hex Shaft
Pros:

• Smooth fit onto our hex gears, works much better than hex stock we've gotten elsewhere

Cons:

• It would have been nice if the longer length options were available (in stock).

[kjohnson]

Originally Posted by pfreivald

I think it was as clear as it could reasonably be that the cylinder wasn't included.

It wasn't clear at all. We ordered 2-CIM shifters on January 7. The bold, red text that you see now was not there. The description of the "pneumatic hardware kit" listed in the kit contents was not very descriptive at all and as a team that had never used shifting gearboxes before, we assumed the cylinders were included. The webpage has since been corrected, obviously.

We ordered early enough that we were able to place an additional order for the cylinders and had no problems getting the shifters or cylinders in a timely fashion.

[jwfoss]

I mentioned in my previous post that 558 is using a modified 2014 Drive in a Day chassis, attached is a picture of our practice chassis. We added the ability to run an un-equal spaced 8wd and bolted in some of the single reduction single speed gearboxes. We are very happy with how this chassis is performing. Please excuse the quality of the image.

[Trent B]

Originally Posted by Paul Copioli

1. Motor mounting and efficiency. Although the gears are very efficient, in some cases the motor mounting was putting undo pressure on the motor shaft causing excessive efficiency loss. We solved this problem by making plastic motor mounts and eliminating the input bearing. This gives about a 20% increase in efficiency.

I am slightly unclear on how VPs should be assembled given there is still documentation about the metal plate on your website. (In particular, the user guide which students used to assemble the motors makes no mention of the plastic plates)

Our gearboxes came with the metal and plastic motor mounting plates, they were assembled with the metal motor mounting plates. Is this a satisfactory motor mounting scheme with the absence of the bearing, or should they be swapped out for the plastic mounting plates.

[Aren_Hill]

Originally Posted by Trent B

I am slightly unclear on how VPs should be assembled given there is still documentation about the metal plate on your website. (In particular, the user guide which students used to assemble the motors makes no mention of the plastic plates)

Our gearboxes came with the metal and plastic motor mounting plates, they were assembled with the metal motor mounting plates. Is this a satisfactory motor mounting scheme with the absence of the bearing, or should they be swapped out for the plastic mounting plates.

Trent,

I updated the user guide but forgot about the quick start guide.
Please refer to This Guide for motor mounting.

With a BAG or 775 you should be fine with the metal plate, 550 or AM9015 you should replace to the plastic plate.

-Aren

[Trent B]

Originally Posted by Aren_Hill

With a BAG or 775 you should be fine with the metal plate, 550 or AM9015 you should replace to the plastic plate.

It has a BAG motor so we should be fine.

Thanks

[JesseK]

Did something change with the VersaPlanetaries or were they always so easy to mate together with a BAG motor? We assembled them with RS-775 & RS-550 motors last year and still had some minor binding after several attempts from 4 different individuals. Both VersaPlanetaries went together very smoothly this year on the first try with BAG motors.

The new bearing gussets are very nice. The 'end' gusset is very easy to bend at the same point with imprecise equipment, allowing us to add a long roller intake on top of a plate.

We were happy to find the 7:1 VP ratio. It matched our intake roller speed to our drive train speed very nicely.

One product I'd like to see in the future is a 1/2" hex-hex shaft coupler. We're getting away with a beefy 3D printed Nylon coupler on a low-torque application for now, but an Aluminum coupler with built-in shaft collars would be nice for high-powered applications. The printed coupler went through many iterations for tolerance, strength & brittleness before the final iteration, which works like a champ.

On another note, I'm surprised the teams surrounding the IFI warehouse aren't screaming 'free USPS shipping on a single low-value item if you send us team t-shirts or 3D print us something'. I wanted to order a 10:1 gear kit by itself and the shipping was more than the part. It wasn't a huge deal - we tacked it onto a larger order a week later, but it also meant we got our production ratios a week later than desired.

[magnets]

Now that I've stopped in with a team that has some more vex parts, I thought I'd post my opinions.

Overall, the quality of the parts/packaging/documentation is very, very good. The ball shifter is small, light, and functional. It does a good job of shifting on the fly, and spends almost no time in the neutral position. Many of the products have very neat features, like the two sets of holes for the CIM's to go with different pinions, and the really neat profile shift gears with different teeth and same pitch diameter. These are really neat parts to use in FRC.

There are two parts that I'm not a big fan of, and these are the 40 tooth dog gear, and some of the pinions. The bearings (which come pressed/locktited into the gear) stick out the end, which is a little weird. Once you pop the bearing out to replace it with one that actually fits, you'll notice that the hole is oversize, and you'll need to get some locktite. The dog pockets are also way bigger than they need to be. It would also be nice to see fillets on the 40 tooth gear like there are on the 44. I don't have a vex dog with me, but the CAD model shows no fillets there either, unlike the AM ones. We've found that these fillets make a lot of difference. Those right angles are huge places for stress to concentrate.

The issue with the pinions has no easy solution and isn't a vex problem, but the retaining clip for the CIM shaft has too big of an OD, so it catches on whatever gear the CIM motor is driving. This makes swapping out a CIM pretty tricky.

[Akash Rastogi]

Saw this today. Anyone else have issues with the VEX mecanum wheels? I saw earlier reports of issues with the 6" wheels.

http://blog.spectrum3847.org/2014/02...days-like.html I hear 4265 had similar issues.

[cadandcookies]

Originally Posted by Akash Rastogi

Saw this today. Anyone else have issues with the VEX mecanum wheels? I saw earlier reports of issues with the 6" wheels.

http://blog.spectrum3847.org/2014/02...days-like.html I hear 4265 had similar issues.

I think this post clears up the 4" wheel problems a little bit.

[magnets]

I agree with the mecanum wheel issue. There's two ways these things fail. The rollers come loose, and the plastic wheel itself shatters. I broke a 6 inch one dropping it on the floor.

One more question for the vex guys, why is the slot in the dog shifting shaft so long? It's significantly longer than the travel of the cylinder.

[Answer42]

Originally Posted by magnets

I agree with the mecanum wheel issue. There's two ways these things fail. The rollers come loose, and the plastic wheel itself shatters. I broke a 6 inch one dropping it on the floor.

One more question for the vex guys, why is the slot in the dog shifting shaft so long? It's significantly longer than the travel of the cylinder.

You'll find that's the case for most dog shifting gearboxes you can buy. I would assume it just makes the whole setup more tolerant inaccurate cylinder placement. Although I'd be curious to hear what the reasoning is from vex.