Sorting out drill motors

hi all

i will need to put some screws into my drill motors in order for them to work properly, i know the procedure but just wanted to check the postioning (black dot), i have attached a link so if someone could tell if im on the right lines

http://www.psychoflingteam.co.ukwww.psychoflingteam.co.uk then robot improvements

thanks alex

Whats that for? To stop the clutch from slipping?
I wouldnt take such a destructive approach to it, just get a short bolt (m5 i think) and just screw it into the holes in the front where the metal balls used to be. Theres notches in the torque ring inside, you want the end of the bolt to go into one of these notches and screw in the bolt untill it just about touches the ring, then undo by a quarter of a turn to make sure that your not squashing it.

http://cpc.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU=FN00233http://cpc.farnell.com/jsp/endecaSea...sp?SKU=FN00233

Just ordered some of them myself to lock-up my drills - theyve got an allen key head, and as Grant said, they just go into the holes where the ball bearings were (youll probably need to tap an M5 thread in it first so the screw doesnt meet too much resistance when going in). The screws in the above link are short enough so that once theyre pressing on the clutch, the heads lie flush with the plastic casing. Helps a lot if youre using drill mounts that sit flat against the plastic casing

RS have similar screws. Just search for grub screws

http://www.robowars.org/guides/guides-drill-hacking.htmlhttp://www.robowars.org/guides/guide...l-hacking.html

thanks guys

so the grub screws screw into the ball bearing holes and they stay in there beacuse of the plastic sides?

i wouldnt need to go into the metal ring with the notchs on, would i? if yes how?

thanks alex

the grub screws screw into the ball bearing holes YES

i wouldnt need to go into the metal ring with the notchs on, would i? Not thru the side... NO.

(Message edited by woody on March 30, 2007)

so they wont fall out or anything?

thanks alex

No, the thread of the grub screws interlock with the plastic casing, preventing them from falling out. Its the same principle as putting a screw into a piece of wood - you wouldnt expect a screw to just fall out of a piece of wood (unless the screwhole in the wood was bigger than the screw, in which case, what did ya think was gonna happen? :)). The grub screws will have the pressure of the clutch pressing on them, but because the thread is slightly larger than the hole and is cutting into the plastic, they wont pop out when in use.

(Message edited by K_C_R on March 30, 2007)

the link put by you jamie is showing that they are out of stock will these be suitable

http://www.rpmechatronics.co.uk/shop/index.php?cPath=28_66http://www.rpmechatronics.co.uk/shop...hp?cPath=28_66

8th one down

alex

can anyone see how many sre in each packet?

I like this place better
http://modelbearings.co.uk/http://modelbearings.co.uk/
I have got alot of screws from that place and the guy running it is excellent

just ordered some off the site

cheers to all

alex

deleted

(Message edited by woody on March 30, 2007)

odd question - what is the length of the average drill motor from motor to gearbox without the length of the threaded shaft?

I make mine to be 110mm, or 115mm if you include the tabs on the motor

Thanks Jamie. Nice quick response btw.

No probs - was working on my drill motors at the time I saw your post anyway :)

got my grub screws today all fitted and seem when i turn the wheels at least they seem to work

at magna james b suggested using washers on the wheels, what size i tried some and the fitted into the hole made for the nut perfect but wont this make it worse? im using 75mm ones from ewan

on a totally different point i plan to use an aerial that comes out iof the robot but this means stripping the end of my wire aerial is this ok to do?

cheers alex

I got some of http://www.screwfix.com/app/sfd/cat/...id=14327>these

when it says m10 i presume it means the the washers diamete, not the hole its self?

thanks alex

No, M10 refers to the 10mm hole in the centre of the washer - drill axles are ~10mm in diameter; these washers will fit on them and stop the wheels from going all the way up the drill shaft and rubbing on the casing/mounts

oh well james said to put them on the outside i think, beacuse the nut is only melted in and may if it takes a big nock come out, and to stop this use a washer, do i have the wrong end of the stick?

alex

Nope sorry, Ive got the wrong end of the stick (or the wrong end of the wheel to be more exact :))

The washers youre after are for going on the reverse threaded screw that screws into the drill shaft yeah?
If so, I think my washers are about 10-12mm outer diameter with the hole for the reverse screw (cant remember the diameter off-hand) but I think youll probably need ones with a bigger outer diameter (maybe about 25mm?) to spread the load more

yeah thats right cheers jamie for you r help

alex

put the m10 washers on the inside of the wheel, and the smaller washers on the outside. when we spoke at magna, i was suggesting that you use a washer on the outside of the wheel large enough that it does not pull into the wheel shaft hole. if the wheel is held on by putting a small washer on the reverse thread screw to hold the nut on, and not the wheel, you may have problems with the wheel getting knocked off centre and wobbling, or coming off completely. hold the wheel on by the wheel, using the nut melted into the wheel to transfer just the torque, not the side loads. the wheel life is longer this way

ive tried running it on the floor where i was having problems, and result it works! and plus it works with the top on and failsafes well. but it isnt the fastest thing ever how can i increase the speed? i already have 14.4volts...

big thanks for everyones help

alex

MORE Volts.

Bigger Wheels ?

Alex, what voltage drills are they?
if they are 9.6v, Id suggest 14.4v is the most you can reliably use (by reliable I mean they should last one event) I have run 9.6v drills at 21.6v, but they eat themselves very quickly.

If you are using higher voltage drills, as a rough guide, add 50% to their voltage, so run 12v drills on 18v etc. As I say, you can push harder, but it gets expensive to replace your motors every fight.

Out of interest, how have you wired your motors? Are they in series or parallel? they must be in parallel or they will only see 7.2v each. It may be a silly question, but it is more common than you think. Also, have you checked the electronize speed gain is turned up to maximum?

hope this helps.

If theyre 9.6V at 14.4V then it should be going pretty damn quickly (on 75mm wheels yeah?) as thats the setup Im running too at the moment. Check all the points that James said, but particularly with the wiring of the batteries/motors. Im using four 7.2V packs in mine, wired in parallel to boost the Ah then wired in series to get the 14.4V - first time I connected it up though it was reeeeeaaally slow, was majorly disappointed. Was the next morning before I realised I they were only getting 7.2V and that I had duffed the connections :)

its actually the motors being in parallel im refering to Jamie, not the batts.

If you are running 4 motors, Im assuming you have 2 on each speed controller, meaning only 2 controllers needed.

If you wire both left side motors correctly, (for example), to one electronize controller, one or 2 things can happen.

you can connect the motors in series, meaning the 2 motors share the 14.4v under normal running, giving 7.2v each. (this is not always the case, as one wheel may spin for example, then the spinning wheel gets move voltage). Under normal running, this method means the robot runs at a speed that suggests it has only 7.2v of batts on board.

or.... you can connect the 2 motors in parallel, giving 14.4v per motor. The robot runs twice as fast as if wired in series, and has more power, but current is also much higher so be careful.

if you have wired in parallel, run the motors at 150% voltage, setup the controllers right, and charged your batts, the only other ways to get more speed are to...

a) bigger wheels as suggested above
b) pull one stage of gears out of the gearbox :)
c) remove the ferrite rings on the motor.

all of which reduce pushing power and acceleration.

hope this clears it up.

the motors are 12volt
the wheels are 75mm

later today ill put some pic on the website of my setup,
ill try some the suggestions and post the rusults

thanks alex

thanks alex

the pics have been uploaded, hand drawn as my serif draw was playing up

http://www.psychoflingteam.co.ukwww.psychoflingteam.co.uk

then robot improvements

if someone could give advicwe now seeing the setup that would be great!

thanks alex

Your motors are drawn as connected in parrallel giving 14.4 volts to each motor..... so you already have the fastest battery/motor setup.
Possible upgrades ..... Increase the voltage a LITTLE .......thatll probably mean new bats.

Replace the motors with 9.6v ones ....Ewan sells some.

Increase the wheel diameter .... But as pointed out this will increase the load on your motors and reduce pushing power.

MY preference ... 9.6 volt motors.

(Message edited by woody on April 04, 2007)

What was the rpm of the motors at 12v ?

id agree completely with Woody there, just ask Tony Booth how effective 9.6v motors are on 14.4v. Baromot went for a ride on one of my 2 wheel drive 6kg paytodrives with this setup. 4 of these motors at 14.4v in a 12 kg robot are pretty nippy with plenty of push.

disaster something has happened, i was testing it without the top working fine, but then tried the top on and it wasnt moving and then i saw white smoke instsntly i pulled the link and investigated, the cause of this was a burnt terminal block which seemed to be conducting on to the aerial. it had melted the terminal block but nothing major seemed to have happened, but i want to check in a mo im putting numerous pics of the pieces on my website can some check if that was the only cause? also the battteries seemed to warm...
the terminal block is smaller than i usaully use, is this a cause?
thanks alex
http://www.psychoflingteam.co.ukwww.psychoflingteam.co.uk
robot improvements

disaster

i was testing the drive and it was fine, so i put the top on, nothing moved then white smoke
i instantly pulled the link a had a look, a terminal block seemed to have melted for some reason. i think the cause may have been the aerial touching a wire then smoking, could this happpen?

im putting pics on my site so if someone could see if there is another cause.

also the the terminal block is smaller than usual and the batteries seemed to be warm?

thanks alex
http://www.psychoflingteam.co.ukwww.psychoflingteam.co.uk
robot improvements

they are now uploaded, i have also included pics of the normal size terminal block and the protection aroung my batteries

any advice wanted...

alex