Go to Post On a side note... "Think outside the robot." - I kinda like that. I'll have to use that in a meeting someday.... - Not2B [more]
Home
Go Back   Chief Delphi > Technical > Motors
CD-Media   CD-Spy  
portal register members calendar search Today's Posts Mark Forums Read FAQ rules

 
Closed Thread
Thread Tools Rate Thread Display Modes
  #16   Spotlight this post!  
Unread 14-05-2008, 21:42
gburlison gburlison is offline
Mentor
FRC #0662 (Rocky Mountain Robotics)
Team Role: Mentor
 
Join Date: Sep 2002
Rookie Year: 2000
Location: Colorado Springs, CO
Posts: 245
gburlison is a name known to allgburlison is a name known to allgburlison is a name known to allgburlison is a name known to allgburlison is a name known to allgburlison is a name known to all
Re: CIM direct drive

McMaster sells metric broaches and metric drill bits. Start with a sprocket that is undersized and enlarge the bore with the metric drill and then broach with the 2mm broach. Not sure how many sprockets you will find with a bore of 8mm (5/16") or less.
__________________
Gordon Burlison - Mentor
662/Rocky Mountain Robotics
"Every silver lining's got a Touch of grey - Robert Hunter"
"No sense in being pessimistic, it wouldn't work anyway"
  #17   Spotlight this post!  
Unread 14-05-2008, 21:58
RyanN's Avatar
RyanN RyanN is offline
RyanN
AKA: Ryan Nazaretian
no team
Team Role: Mentor
 
Join Date: Jun 2006
Rookie Year: 2005
Location: Austin, TX
Posts: 1,127
RyanN has a reputation beyond reputeRyanN has a reputation beyond reputeRyanN has a reputation beyond reputeRyanN has a reputation beyond reputeRyanN has a reputation beyond reputeRyanN has a reputation beyond reputeRyanN has a reputation beyond reputeRyanN has a reputation beyond reputeRyanN has a reputation beyond reputeRyanN has a reputation beyond reputeRyanN has a reputation beyond repute
Re: CIM direct drive

In the past we've directly put a sprocket on a CIM, but it went to a larger sprocket that went into our custom 2 speed transmission. We never really had trouble with the setup, but the more chains you get, the more master links that can fall out... (IRI 2006 right before alliance picking). AndyMark products are nice and reliable, but they are a bit expensive ($88 for the toughbox that shipped in the KOP). Banebots are still pretty expensive... the cheapest is $83. I'm not sure of your ability to build your own parts with a mill or CNC mill, but custom is probably the cheapest way to go, but also the most time consuming. Chain's are probably the easiest way to go, but their reliability becomes the issue. Gears are the hardest way to go, but their reliability is among the best.

Keep in mind that from 2003 to 2006 we used chains in our custom transmissions and had very little problems, but the problems we had were with the chain derailing or the master links falling out. The chain never broke and we used #25 chain. You may also look into regular bicycle chain as it is easy to find and fairly cheap. We've been looking into bicycle chain as an option next year because we are stretching the limits of the #25 chain as far as the forces we apply to it. Luckily with our 4 CIM drive this year, we had no drive train issues at all (knocks on wood for IRI)
__________________
Taking a break from mentoring for a few years. (Is that allowed?!?)

Controls Mentor
@rnazaretian

Previous teams:
Team Fusion, FRC 364
Garnet Squadron, FRC 4901
  #18   Spotlight this post!  
Unread 14-05-2008, 23:00
s_forbes's Avatar
s_forbes s_forbes is offline
anonymous internet person
FRC #0842 (Falcon Robotics)
Team Role: Engineer
 
Join Date: Jan 2006
Rookie Year: 2006
Location: Phoenix, AZ
Posts: 1,156
s_forbes has a reputation beyond reputes_forbes has a reputation beyond reputes_forbes has a reputation beyond reputes_forbes has a reputation beyond reputes_forbes has a reputation beyond reputes_forbes has a reputation beyond reputes_forbes has a reputation beyond reputes_forbes has a reputation beyond reputes_forbes has a reputation beyond reputes_forbes has a reputation beyond reputes_forbes has a reputation beyond repute
Re: CIM direct drive

Quote:
Originally Posted by squirrel View Post
Did you grind flats on the motor shafts, for the set screws to seat against?
I think a modification to the motor shafts is illegal dad... gosh, read the manual!
  #19   Spotlight this post!  
Unread 14-05-2008, 23:05
RyanN's Avatar
RyanN RyanN is offline
RyanN
AKA: Ryan Nazaretian
no team
Team Role: Mentor
 
Join Date: Jun 2006
Rookie Year: 2005
Location: Austin, TX
Posts: 1,127
RyanN has a reputation beyond reputeRyanN has a reputation beyond reputeRyanN has a reputation beyond reputeRyanN has a reputation beyond reputeRyanN has a reputation beyond reputeRyanN has a reputation beyond reputeRyanN has a reputation beyond reputeRyanN has a reputation beyond reputeRyanN has a reputation beyond reputeRyanN has a reputation beyond reputeRyanN has a reputation beyond repute
Re: CIM direct drive

Quote:
Originally Posted by s_forbes View Post
I think a modification to the motor shafts is illegal dad... gosh, read the manual!
Actually, modifying the shaft is not illegal.

Quote:
<R61> So that the maximum power level of every ROBOT is the same, motors used on the ROBOT shall not be modified in any way, except as follows:
  • The mounting brackets and/or output shaft/interface of the motors may be modified to facilitate the physical connection of the motor to the ROBOT and actuated part.
  • The gearboxes for the Fisher-Price and Globe motors are not considered “integral” and may be separated from the motors.
  • The electrical input leads on the motors may be trimmed to length as necessary.
The intent is to allow teams to modify mounting tabs and the like, not to gain a weight reduction by potentially compromising the structural integrity of any motor. The integral mechanical and
electrical system of the motor is not to be modified. Note that FIRST will not provide
replacements for modified parts.
__________________
Taking a break from mentoring for a few years. (Is that allowed?!?)

Controls Mentor
@rnazaretian

Previous teams:
Team Fusion, FRC 364
Garnet Squadron, FRC 4901

Last edited by RyanN : 14-05-2008 at 23:10.
  #20   Spotlight this post!  
Unread 15-05-2008, 00:19
Manoel's Avatar
Manoel Manoel is offline
Registered User
FRC #0383 (Brazilian Machine)
Team Role: Mentor
 
Join Date: Jun 2001
Rookie Year: 2000
Location: Porto Alegre, RS, Brazil
Posts: 608
Manoel has a reputation beyond reputeManoel has a reputation beyond reputeManoel has a reputation beyond reputeManoel has a reputation beyond reputeManoel has a reputation beyond reputeManoel has a reputation beyond reputeManoel has a reputation beyond reputeManoel has a reputation beyond reputeManoel has a reputation beyond reputeManoel has a reputation beyond reputeManoel has a reputation beyond repute
Send a message via ICQ to Manoel Send a message via MSN to Manoel
Re: CIM direct drive

Quote:
Originally Posted by Cory View Post
we had a heck of a time keeping our pinions in place this year. Due to having 2 gears on one CIM shaft we had no room to use retaining clips like we usually do and we had to rely on a setscrew to keep the gear from moving. Even with 2 set screws 90* from each other the gears would slide out and eventually maul themselves on the adjacent gear. We had to resort to green loctiting them, which didn't work well either when we didn't let it set for 24 hours.

Furthermore the only way to release the loctite is heat. I melted a bit off one of our Delrin sideplates the other day trying to break a stubborn one free.

We hate setscrews and figured this was probably one application where they might be OK. Lesson learned-never again will we rely on them.
We've had problems using M3 setscrews to hold a gear to the CIM shaft (mainly because the small allen key prevented us from tightening the screw properly) but switching to M4 setscrews completely solved our problem (both last year with a high torque, two-speed gearbox and this year with a single, high speed gearbox).
__________________
Manoel Flores da Cunha
Mentor
Brazilian Machine
Team # 383
  #21   Spotlight this post!  
Unread 15-05-2008, 00:49
Doug G's Avatar
Doug G Doug G is offline
Coach / Teacher
FRC #0701 (Robovikes)
Team Role: Coach
 
Join Date: Dec 2002
Rookie Year: 2001
Location: Fairfield, CA
Posts: 880
Doug G has a reputation beyond reputeDoug G has a reputation beyond reputeDoug G has a reputation beyond reputeDoug G has a reputation beyond reputeDoug G has a reputation beyond reputeDoug G has a reputation beyond reputeDoug G has a reputation beyond reputeDoug G has a reputation beyond reputeDoug G has a reputation beyond reputeDoug G has a reputation beyond reputeDoug G has a reputation beyond repute
Re: CIM direct drive

We have used 5/16" bored gears/spockets and a 3/32 keyway. With a little filing, they fit right on the 8mm CIM shaft and then get a piece of 3/32 key and file it to fit. We've made 3 types of transmissions this way and also used this method for our ball shooter in 2006 which used #25 sprockets mounted on the CIM shaft. Never had a failure... yet.
__________________
Work Hard, Have Fun, Make a Difference!

  #22   Spotlight this post!  
Unread 15-05-2008, 02:00
Cory's Avatar
Cory Cory is offline
Registered User
AKA: Cory McBride
FRC #0254 (The Cheesy Poofs)
Team Role: Engineer
 
Join Date: May 2002
Rookie Year: 2001
Location: Redwood City, CA
Posts: 6,824
Cory has a reputation beyond reputeCory has a reputation beyond reputeCory has a reputation beyond reputeCory has a reputation beyond reputeCory has a reputation beyond reputeCory has a reputation beyond reputeCory has a reputation beyond reputeCory has a reputation beyond reputeCory has a reputation beyond reputeCory has a reputation beyond reputeCory has a reputation beyond repute
Send a message via AIM to Cory
Re: CIM direct drive

Quote:
Originally Posted by Manoel View Post
We've had problems using M3 setscrews to hold a gear to the CIM shaft (mainly because the small allen key prevented us from tightening the screw properly) but switching to M4 setscrews completely solved our problem (both last year with a high torque, two-speed gearbox and this year with a single, high speed gearbox).
We had one gear with a 4-40 and one with a 6-32. Both performed equally poorly.
__________________
2001-2004: Team 100
2006-Present: Team 254
  #23   Spotlight this post!  
Unread 15-05-2008, 08:51
Brandon Holley's Avatar
Brandon Holley Brandon Holley is offline
Chase perfection. Catch excellence.
AKA: Let's bring CD back to the way it used to be
FRC #0125 (NU-TRONs, Team #11 Alumni (GO MORT))
Team Role: Engineer
 
Join Date: Jan 2004
Rookie Year: 2001
Location: Boston, MA
Posts: 2,593
Brandon Holley has a reputation beyond reputeBrandon Holley has a reputation beyond reputeBrandon Holley has a reputation beyond reputeBrandon Holley has a reputation beyond reputeBrandon Holley has a reputation beyond reputeBrandon Holley has a reputation beyond reputeBrandon Holley has a reputation beyond reputeBrandon Holley has a reputation beyond reputeBrandon Holley has a reputation beyond reputeBrandon Holley has a reputation beyond reputeBrandon Holley has a reputation beyond repute
Send a message via AIM to Brandon Holley
Re: CIM direct drive

Quote:
Originally Posted by Cory View Post
we had a heck of a time keeping our pinions in place this year. Due to having 2 gears on one CIM shaft we had no room to use retaining clips like we usually do and we had to rely on a setscrew to keep the gear from moving. Even with 2 set screws 90* from each other the gears would slide out and eventually maul themselves on the adjacent gear. We had to resort to green loctiting them, which didn't work well either when we didn't let it set for 24 hours.

Furthermore the only way to release the loctite is heat. I melted a bit off one of our Delrin sideplates the other day trying to break a stubborn one free.

We hate setscrews and figured this was probably one application where they might be OK. Lesson learned-never again will we rely on them.
We ran into a similar problem in our 3 motor gearbox. Because we did not have enough clearance to extend the shaft to add a retaining ring we had to resort to some old school methods....superglue works wonders sometimes. It is by no means the most elegant solution, but we did not need a set screw, retaining ring, or anything but superglue to hold the pinions on the CIM motors and AM FP planetaries. You don't need heat to remove them either (although I'm sure a little heat wouldn't hurt), a quick pop with a screwdriver or chisel will break the superglue and the pinion will come right off.
__________________
MORT (Team 11) '01-'05 :
-2005 New Jersey Regional Chairman's Award Winners
-2013 MORT Hall of Fame Inductee

NUTRONs (Team 125) '05-???
2007 Boston Regional Winners
2008 & 2009 Boston Regional Driving Tomorrow's Technology Award
2010 Boston Regional Creativity Award
2011 Bayou Regional Finalists, Innovation in Control Award, Boston Regional Finalists, Industrial Design Award
2012 New York City Regional Winners, Boston Regional Finalists, IRI Mentor of the Year
2013 Orlando Regional Finalists, Industrial Design Award, Boston Regional Winners, Pine Tree Regional Finalists
2014 Rhode Island District Winners, Excellence in Engineering Award, Northeastern University District Winners, Industrial Design Award, Pine Tree District Chairman's Award, Pine Tree District Winners
2015 South Florida Regional Chairman's Award, NU District Winners, NEDCMP Industrial Design Award, Hopper Division Finalists, Hopper/Newton Gracious Professionalism Award
  #24   Spotlight this post!  
Unread 15-05-2008, 22:30
Manoel's Avatar
Manoel Manoel is offline
Registered User
FRC #0383 (Brazilian Machine)
Team Role: Mentor
 
Join Date: Jun 2001
Rookie Year: 2000
Location: Porto Alegre, RS, Brazil
Posts: 608
Manoel has a reputation beyond reputeManoel has a reputation beyond reputeManoel has a reputation beyond reputeManoel has a reputation beyond reputeManoel has a reputation beyond reputeManoel has a reputation beyond reputeManoel has a reputation beyond reputeManoel has a reputation beyond reputeManoel has a reputation beyond reputeManoel has a reputation beyond reputeManoel has a reputation beyond repute
Send a message via ICQ to Manoel Send a message via MSN to Manoel
Re: CIM direct drive

Quote:
Originally Posted by Cory View Post
We had one gear with a 4-40 and one with a 6-32. Both performed equally poorly.
I forgot to mention that the hole was collinear with the keyway such that the setscrew had a flat surface to press against.

Did you guys do it different?
__________________
Manoel Flores da Cunha
Mentor
Brazilian Machine
Team # 383
Closed Thread


Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Wheel direct drive molly Technical Discussion 15 25-01-2008 00:32
your thoughts on the FP CIM/2.5 CIM motor drive setup versus 2 2.5 CIM motors waialua359 Motors 11 14-12-2007 04:29
Help! Direct Drive Issues roberthan Motors 16 21-09-2006 09:33
pic: 1097 Direct Drive 01 Anthony Kesich Robot Showcase 16 13-09-2005 22:33
Direct drive or Chain? Suneet Technical Discussion 32 27-03-2003 23:00


All times are GMT -5. The time now is 15:27.

The Chief Delphi Forums are sponsored by Innovation First International, Inc.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Copyright © Chief Delphi