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View Full Version : Help on removing gear at end of Minbea stepper motor shaft



arun_ajs
03-30-2009, 06:22 PM
I have purchased a pair of Hi-Torque Stepper-Motors from "SunROM Tech", for direct driving the wheels of my Robot.
The stepper model is Thailand company "MINEBEA" make "16PU-M301-G1" . It comes with a gear at the end of its shaft.
Picture is in SunROM site. I want to remove this gear, so that the wheel can be fixed into the motor-shaft. The gear will not go into the wheel-hole: too big.

Now I do not know how the gear has been fixed in to the shaft by the manufacturer. (threaded, bonded or press fit or some other way).
Does anybody have any previous experience with this model. Can anybody advice me how to go about removing it, without damaging the shaft/motor?
Suggestions are welcome.

Incidentally this motor is the same model as the one originally sold by Robokit, (but without the gear) but with an aluminium wheel. (RKI-1040)

Picture of motor: http://www.sunrom.com/index.php?main_page=product_info&cPath=49&products_id=550
thanks & regards.

allbits
03-31-2009, 07:38 AM
use a puller.

firoz
03-31-2009, 08:37 AM
its press fit,with very close mechanical tolerance.
best is puller.but usually u won't find it.

so hold the gear in vice(or like cutting plier u might destroy the gear little :-)
and hit the shaft with a hard pin(shld be strong we call it dowel in industry) slowly.if u are good.the gear will stuck in vice and the motor will slip down.
remember the pin used shld be less in dia meter than motor shaft.

arun_ajs
03-31-2009, 03:24 PM
@allbits, firoz
Many Thanks for your suggestions.

I assume this puller, is a specialized tool, for removing such gears from motor shafts, even though I do not know it, or have seen one sofar.

Any idea where this tool will be available for a suitable small size motor like mine. (The shaft diameter is 5 mm & gear dia is approx 10 mm).

Will this be available in common Engineering workshops?
or is it a cheaper tool to purchase?

@firoz
The manual method you have suggested, have you tried out personally for this specific stepper model with gear? I am worried whether it will damage the shaft or motor?

regards

firoz
04-01-2009, 10:04 PM
yes it will work.just need little bit of skill.while hitting,you shld carefull that u don't hit on gear.the hitting force shld come only on motor shaft.

As the motor is floating and u held the gear,when u hit the shaft,it will slide easily.
don't worry i did this million times.iam less hobbiest and more professional now :-)

and abt this gear puller,never seen one for such small motors.we do have gear puller but that meant for huge shafts of machine tool.
and most imp why a hobbiest want to buy gear puller just to remove one gear :-)

the gear sld be(not sure) made of brass,which is soft material.so it will slide off easily.

just remember one point,motor shld be in air,and hold the gear with strong tool(vice or plier),then hit the shaft from top with pin smaller the diameter of motor shaft.
i hope u got it. :-)

I (we) learn from experience.just do it.later u will say how easy it was

firoz
04-01-2009, 10:20 PM
and i forgot
usually motor shafts are made of hardened material.(case hardening)
so the pin u use shld have flat face.shld not be sharp or it might damage the motor shaft face.

http://img18.imageshack.us/img18/4346/54214647.jpg

arun_ajs
04-02-2009, 12:39 AM
Hi Firoz
I can see that, you are a very helpful person. Thanks.

I am planning to do as u suggested, if I am not getting hold of a gear-puller.
But as u said, that is hard to find.
Any way I will be posting back my experience.
Agains Thanks for your time & effort.

demonslayer
02-25-2010, 03:35 PM
its press fit,with very close mechanical tolerance.
best is puller.but usually u won't find it.

so hold the gear in vice(or like cutting plier u might destroy the gear little :-)
and hit the shaft with a hard pin(shld be strong we call it dowel in industry) slowly.if u are good.the gear will stuck in vice and the motor will slip down.
remember the pin used shld be less in dia meter than motor shaft.
dude i had the same problem and was stuck wid the problem 4 a very long time.....
i tried wat u suggested and guess wat.....the gear came out quite easily enough....
thnx 4 the advice......

rao
02-26-2010, 09:50 AM
@demonslayer:

Even though this thread is an year old but I really appreciate you searching the forums and I am glad that you were able to find what you were looking for.

I hope others follow your example rather than making new posts for already answered problems all the time.

Rao