Large gear ratio 3

[larbar]

Hi all,
I am curently working for a small company as a developement engineer and I have to design a basic gear system to rotate a robot bird.I am not very experienced with gears and i am finding it hard to create a ratio of 1:10 within a relativly small space (approx. 250mm x 100mm x 165mm)with just two spur gears.

Is this feasable or would I be better to use a system of several spur gears to gradually create the neccessary ratio.

Any advice would be great.
Laurence

 

[tygerdawg]

Perhaps you may look at planetary gearheads from Alpha Gear, Danaher, many others.

TygerDawg
Blue Technik LLC
Virtuoso Robotics Engineering

http://www.bluetechnik.com

 

[larbar]

Sry
The gear ratio is 10:1
Laurence

 

[alansimpson]

Drive companies like Berg, SDP will have range of small gears and assemblies. If you realy need to go compact (and pricy) harmonicdrive.

 

[diskullman]

Why not try a worm gear?

Russell Giuliano

 

[eromlignod]

10:1 is a little small for a single-start worm gear set (the pinion would have to have only 10 teeth). But you can get double-start and 4-start worm/wormgear sets that will give you 10:1 in a very small space. Take a look at:

https://sdp-si.com/eStore/

Don
Kansas City

 

[Bribyk]

Look at how manual vehicle transmissions function. You can use two shafts with one gear locked to each shaft and a number of other gears that freewheel on the shafts that are locked to other gears to create a very compact assembly.

 

[TheTick]

10:1 is not a big reduction. No big deal. All that matters is the relative size of the gears. Could be big gears, could be small gears. The only requirement is one gear has 10x more teeth than the other.

The actual size of the gears is determined by the torque transmitted. You haven't discussed this at all.

 

[MadMango]

For your size restraints, gear ratio, and probably torque and speed, have you looked into automotive window motors?

 

[JakeAdkins]

I am assuming that these gears are not being built 'in house' so you don't have a resident gear expert to ask, that's why you are asking us.

I would start with a basic spur gear set. Decide what the largest 10:1 ratio will fit in your package space. Contact your gear suppler tell them the gear set you want to use and all the input and out put variables, ask them to run it through their gear software. Most gear suppliers have some kind of software they can run their gears through that will tell you everything you would ever want to know about that gear set. If that is not acceptable then you might want to try a compound gear set or planetary set.

You should have the basic tools to ballpark the answer, the gear guys should be able to help you out with the more advanced stuff and you should be able to understand it.

You didn't say anything about the operating life or lubrication type those are also important.

 

[dinjin]

You might want to consider a sprocket and belt design
depending on your loads.

 

[tygerdawg]

I dunno larbar, but I spent about 30 seconds looking at the AlphaGear planetary gearhead catalog

http://www.alphagear.com/file/WITTENSTEIN_alpha_GK2008_USA_en.pdf

and saw a few that fit your description.

TygerDawg
Blue Technik LLC
Virtuoso Robotics Engineering

http://www.bluetechnik.com

 

[Allen]

As you are going to build a simple gear train for rotating a robot bird I guess transmitted force and torque is not the issue (they must be relatively small) if so, then you may use any diameter of gears to fit in desired box.

E.g. you may use four spur (or helical) gears with combination of following number of teeth and with the same module which all will give a ratio as 1/10.


z1 z2 z3 z4
1 15 60 20 50
2 15 60 22 55
3 15 60 24 60
4 15 60 26 65
5 15 60 28 70
6 15 60 30 75
7 15 60 32 80
8 16 64 20 50
9 16 64 22 55
10 16 64 24 60

You can purchase them from sdp-si.com as mentioned.

if furthur help needed you must provide more details, e.g. the source of power with input rpm, an desired output rpm, input and output shaft (Parallel, Skewed, Intersecting shafting), etc.

Recommend this PSF handbook for gearing also:

http://gltrs.grc.nasa.gov/cgi-bin/GLTRS/browse.pl?1985/RP-1152.html

Cheers

 

[jedward]

look at a lawn sprinkler for a compact, high gear ratio gear set. compact, inexpensive and possibly a model to follow.

 

[larbar]

hi all.

Great response and really helpfull replies.
Currently out of office for christmas so will be back in the new year with some feedback.

again thanks all.