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-   -   pic: Swerve again, for fun (http://www.chiefdelphi.com/forums/showthread.php?t=131664)

Aren_Hill 22-12-2014 13:29

pic: Swerve again, for fun
 

Andrew Lawrence 22-12-2014 13:30

Re: pic: Swerve again, for fun
 
So when my poem said a new swerve from Aren Hill, it wasn't kidding!

Looks great! What is it geared for? I can't tell from the section view, but it looks like it's cutting close on the clearance for the wheel. Do you know off hand the amount of clearance it is?

Ether 22-12-2014 13:47

Re: pic: Swerve again, for fun
 
Quote:

Originally Posted by Aren_Hill (Post 1415871)
...would rather avoid mercury on the robot (sliprings).

Are there not suitable sliprings for this application which contain no mercury?



Bryce2471 22-12-2014 14:08

Re: pic: Swerve again, for fun
 
A few questions immediately pop up for me:
How is the CIM shaft so short? Isn't it against last year's rules to modify motors?
Where would you get the bevel gears, and how much would they cost?
What's the weight?

Other than that, it looks very good.

JesseK 22-12-2014 14:13

Re: pic: Swerve again, for fun
 
From the cut-out in the other picture, I'm having a hard time figuring out how the large turning gear is mated to the grey-ish ring that acts as the weight-bearing thrust bearing for for the entire robot. It seems like all of the robot's weight is hanging from this ring which is hanging from the gear?

Jared Russell 22-12-2014 14:14

Re: pic: Swerve again, for fun
 
Quote:

Originally Posted by Ether (Post 1415876)
Are there not suitable sliprings for this application which contain no mercury?



A few years back I found it very difficult/impossible to find a non-Mercotac COTS slip ring that was simultaneously (a) rated for FRC current levels and (b) within single-components COTS cost limits. It is possible that you could make your own spring-loaded slip ring, but YMMV with inspectors/rules in a given season.

Andrew Schreiber 22-12-2014 14:40

Re: pic: Swerve again, for fun
 
Quote:

Originally Posted by Jared Russell (Post 1415891)
A few years back I found it very difficult/impossible to find a non-Mercotac COTS slip ring that was simultaneously (a) rated for FRC current levels and (b) within single-components COTS cost limits. It is possible that you could make your own spring-loaded slip ring, but YMMV with inspectors/rules in a given season.

It is possible (now), I don't have the link handy but they do exist. It's for use in wind turbines so it's actually got three wires. I've also found a few on various websites that are rated for 30A continuous.

The Mercotac ones are far lighter though.

orangemoore 22-12-2014 14:43

Re: pic: Swerve again, for fun
 
Quote:

Originally Posted by Aren_Hill (Post 1415871)
This was purely for fun, not a VEXpro item, sorry ;-)

Why can't it be?

tim-tim 22-12-2014 14:54

Re: pic: Swerve again, for fun
 
Quote:

Originally Posted by Bryce2471 (Post 1415885)
How is the CIM shaft so short? Isn't it against last year's rules to modify motors?

By that definition, wouldn't it be illegal to cut/strip CIM motor wires to add connectors of your choice on the ends?

Thad House 22-12-2014 14:56

Re: pic: Swerve again, for fun
 
Quote:

Originally Posted by tim-tim (Post 1415906)
By that definition, wouldn't it be illegal to cut/strip CIM motor wires to add connectors of your choice on the ends?

R30 specifically allows wiring, mounting brackets and output shafts to be modified. That rule has been there for years, so I would assume it would stay.

Kevin Ainsworth 22-12-2014 15:04

Re: pic: Swerve again, for fun
 
It has to be the most compact and lightest swerve to date!
Professional grade designing, I looked through the entire design earlier this year and thought it was brilliant. We tried to design something totally unique but nothing we came up with was as elegant. Thanks for the inspiration!

Bryce2471 22-12-2014 15:14

Re: pic: Swerve again, for fun
 
Quote:

Originally Posted by Kevin Ainsworth (Post 1415909)
It has to be the most compact and lightest swerve to date!

What makes you say that? Do you know the weight?

Bennett548 22-12-2014 15:19

Re: pic: Swerve again, for fun
 
Is the weight of the robot sitting on the cim pinion? I can't figure out the wheel pivot bushing/bearing for this design.

Edit: I see the button heads now. Is that a silverthin bearing?

nuclearnerd 22-12-2014 15:35

Re: pic: Swerve again, for fun
 
It's compact for sure, but I can't figure out the bearing design.

As far as I can tell, all of the vertical loads are taken by the CIM shaft (!), and I can't really tell what takes the horizontal loads. There's an upper steering bearing on the CIM shaft, but the only lower bearing I can see is the white ring below the steering gear and that doesn't have much radial contact. What am I missing?

asid61 22-12-2014 16:40

Re: pic: Swerve again, for fun
 
Quote:

Originally Posted by Bryce2471 (Post 1415911)
What makes you say that? Do you know the weight?

+1. I have a swerve design exactly like this on my computer, except with a 2" colson instead of a 3.25" versawheel, ad it weighs a minimum of 5.3lbs. Still heavier than Bryce's swerve, albeit only very slightly.
Plus, making it into a shifting version requires a lot of weight unless you don't use a COTS shifter shaft.

EDIT: Of course, if anybody could make the design lighter it would be Aren. So it could be lighter actually.

Very nice swerve Aren. It's cool seeing your drives. Are you using a dead axle? Is it possible to flip the cim?


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