Back for more..VEXpro 2014 Product Unveiling

[DampRobot]

Originally Posted by sanddrag

I don't understand this one bit, but I'd like to. Is there a more in depth or perhaps visual explanation?

I spent a good amount of time researching this at one point, and as far as I could tell, to make a gear with less toothcount have the same pitch diameter as a larger gear, you take the gear with the toothcount you want and let the teeth extent all the way out until their involute profiles meet, instead of cutting them off at a given diameter (as you would to make it have it be the normal diameter).

Of course, I may be totally wrong, so someone else feel free to correct me on this.

[Clinton Bolinger]

If teams would like to compare shipping options between VEX (Greenville, TX) and The Robot Space (Lapeer, MI) feel free to check out http://ship.therobotspace.com

The Robot Space provides teams in the Midwest and on the East Coast with Next Day or Second Day shipping at Ground Rates on all VEXpro, VEX and VEX IQ product lines.

Also, be sure to check out all of the products at www.therobotspace.com (we will be working each day to add pictures and more information).

Thanks,
Clinton Bolinger
clinton[at]therobotspace.com

[Steven Donow]

Originally Posted by sanddrag

I don't understand this one bit, but I'd like to. Is there a more in depth or perhaps visual explanation?

This is the best google image result I could find given the term "addendum modification". Pretty neat concept.

Originally Posted by Oblarg

Are you sure? The plastic AndyMark ones held up marvelously this past year.

And look how big those are.

[Steven Donow]

Originally Posted by Andrew Lawrence

And look how big those are.

I've seen quite a few plastic pulleys in drivetrains (I believe 207 are one example of this-they 3d printed wheels at least, not sure about pulleys). And even so, the only usage of pulleys isn't drivetrains...

[Oblarg]

Originally Posted by Andrew Lawrence

And look how big those are.

Sure, but seeing as I didn't see anything even resembling wear on them, I'm not convinced you couldn't get quite a bit smaller with the same material and have it still work.

[Patrick Flynn]

Originally Posted by DevenStonow

This is the best google image result I could find given the term "addendum modification". Pretty neat concept.

My understanding of this is that you are going to shrink your tooth addendum, which in turn will allow you to shrink your tooth width. This allows you to maintain the same circular pitch. By still having the same tooth to tooth spacing.
The depth of mesh is the only measure that will change in this case, also know as the gears clearance.

[ttldomination]

Some of CADs are missing or broken, but otherwise, looks decent. We'll need to seriously assess some of these things and how they would fit into our structure.

Personally, the extended gearboxes are great, but the tubing and gussets don't necessarily work for our team. But then again, they're not really marketed for "us."

- Sunny G.

[MrRiedemanJACC]

Clinton,

Awesome job on The Robot Space. Looks like a great thing for the teams here in Michigan and across the midwest.

Here's the information on shipping when I put it into your calculator to Jackson, Michigan:

Ground: $6.90 vs $8.51
2nd Day $6.90 vs $30.22
Next Day $6.90 vs $81.66

Talk about a no brainer! Hope you have a big warehouse!

I will be sending you a PM on how to get you into our Purchase Ordering system, get you our tax exempt information, etc, etc, etc.... Because we will be buying parts!

John Riedeman

[Paul Copioli]

Profile Shift, or addendum modification, can be positive or negative. For a positive profile shift, the tooth looks longer and pointier. For a negative profile shift, the tooth looks short and stubby.

The primary use for profile shift in industry is to avoid undercut in small gears. If you want to see severe undercut then look at the 12 tooth CIM pinion. Undercut lowers the gear's max load carrying ability and is necessary so the mating gear's tooth tip does not interfere with the root of the smaller gear.

As a rule, every gear we design will have profile shift to avoid undercut except when the market conditions do not allow it. For example, the 14.5 pressure angle, 20 Diametral Pitch gears that have been used as a standard in FRC have always used 0 profile shift. Making a 12T pinion with 0 profile shift now would mean all of the center distances would be too close together.

This is very important for really small gears with small module (1 or .5). All of our VEX motors used in VRC have significant profile shift to increase the load carrying capability.

All of the Versaplanetary gears have addendum modification to minimize the
planetary backlash and increase the strength as much as possible.


You really are shifting the profile either out (+) or in (-). QTC gears has really great introductory information on their web site about gears. I make all my new engineers read that web site before I give them the more advanced information.

By the way, the 11T pinion is actually stronger in every way than the 12T gear due to the 12T gear's severe undercut. However, the 12T gear's strength is plenty sufficient for use with a CIM motor.

Paul

[JVN]

Originally Posted by Paul Copioli

Profile Shift, or addendum modification, can be positive or negative. For a positive profile shift, the tooth looks longer and pointier. For a negative profile shift, the tooth looks short and stubby.

The primary use for profile shift in industry is to avoid undercut in small gears. If you want to see severe undercut then look at the 12 tooth CIM pinion. Undercut lowers the gear's max load carrying ability and is necessary so the mating gear's tooth tip does not interfere with the root of the smaller gear.

As a rule, every gear we design will have profile shift to avoid undercut except when the market conditions do not allow it. For example, the 14.5 pressure angle, 20 Diametral Pitch gears that have been used as a standard in FRC have always used 0 profile shift. Making a 12T pinion with 0 profile shift now would mean all of the center distances would be too close together.

This is very important for really small gears with small module (1 or .5). All of our VEX motors used in VRC have significant profile shift to increase the load carrying capability.

All of the Versaplanetary gears have addendum modification to minimize the
planetary backlash and increase the strength as much as possible.


You really are shifting the profile either out (+) or in (-). QTC gears has really great introductory information on their web site about gears. I make all my new engineers read that web site before I give them the more advanced information.

By the way, the 11T pinion is actually stronger in every way than the 12T gear due to the 12T gear's severe undercut. However, the 12T gear's strength is plenty sufficient for use with a CIM motor.

Paul

...and it's soooo awesome.

[BBray_T1296]

Originally Posted by geomapguy

Are the versa planetary base models 1:1 ratios??

Yes, as they have no actual gears. The ring and planet gears only come with the ratio add-ons.

Originally Posted by Clinton Bolinger

If teams would like to compare shipping options between VEX (Greenville, TX) and The Robot Space (Lapeer, MI) feel free to check out http://ship.therobotspace.com

This is a great tool thanks. I am pretty sure we will never need to ship from Michigan, we will stick to driving 20 miles down I-30 and picking them up from VEX ourselves

[s_forbes]

Originally Posted by Paul Copioli

The primary use for profile shift in industry is to avoid undercut in small gears. If you want to see severe undercut then look at the 12 tooth CIM pinion. Undercut lowers the gear's max load carrying ability and is necessary so the mating gear's tooth tip does not interfere with the root of the smaller gear.

This makes sense, but I don't think our applications are limited by the strength of these undercut gears. The ability to use different tooth counts with the same center-center distance looks like a huge advantage though, especially in the tooth range for pinions. (fun fact: you derailed a recent project of mine with this revelation)

All of the Versaplanetary gears have addendum modification to minimize the planetary backlash and increase the strength as much as possible.

Just making sure: is this something on the new models only? Any compatibility issues with combining stages from last year with stages from this year?


BTW, I appreciate the openness to questions and details from the vexpro guys; it gives me a strong urge to buy your stuff. Good business model.

[JB]

Will the standard 2 cim ball shifter be given the optional lower and 3rd stages seen on the 3 cim version? Also has the bearing blocks / chain tensioning device for the versa frame been placed on the website? I have not be able to locate them.

[AlecS]

Originally Posted by jb1403

Also has the bearing blocks / chain tensioning device for the versa frame been placed on the website? I have not be able to locate them.

Yes the Versa-Block and CAM can be found under /VEXpro/WCP/versachassis, here