Gears

[MarcusWolschon]

Hello,

what does everyone else here do to construct Gears?
Industry standard involute or herringbone gears that mesh coplanar or with a 90° angle between their axis?

I can't believe there is nothing at all to create these. They're used so often in mechanics.

Marcus

 

[albie0803]

Gears have been discussed here often. This program is not suitable for designing gears and the only real important dims are the gear OD's and the centre distances. The gear tooth shape is only cosmetic and means nothing to a gear cutter, unless you want to CNC mill your own gears for some reason. I work for a gear cutting engineering company and all the teeth I make on gears are only eye-candy, so as long as the OD is correct, then as long as it looks vaguely right is all that is necessary. All the relevant info is in a small table, the rest is really superfluous.

For an assembly just blank wheels will do well enough.

 

[dwc]

I just make a disk of the primitive diameter.
If I think there could be conflicts I use the full diameter.
In any case I always constrain to the axle distances so in the construction it makes no difference.
And displaying all the pretty teeth just makes things much slower and the files much larger.
The only exception is when I need to make special tooth forms, but in that case they aren't standard teeth so I know I will never find them in any software tool to make gears anyway. Then I do need to design them myself.
Don

 

[drof34]

Gearing is a rather complex subject and as such this forum is no place for trying to teach it.

Most people just import the drawings for the gear/s they need from a gear manufacturer.

A little knowledge of the subject is very helpful if you are trying to design a gear train.

Alibre is fully capably of designing a gear/s.

I might suggest a book written by Ivan Law entitled GEARS AND GEAR CUTTING.

Jim

 

[Oldbelt]

Hi Marcus.
If you really want to Show GearTrain look in this:
http://www.alibre.com/forum/viewtopic.p ... elt#p46203
Or look in my post there are a loot about gears.

 

[RocketNut]

Howdy Marcus:
I use RushGears.COM (http://www.rushgears.com/Tech_Tools/Par ... Search.php) to design my gears. They have a custom gear design app on there web site. There app allows you design ever aspeck of the gear including pitch,number of teeth, bore diameter, face width, etc. Once your have your gear design you can import it by selecting the importing file type from there list of cad transferring file type (I use STEP 214)

 

[dwc]

I use RushGears.COM

Looks very nice, but their smallest module is almost twice the largest module that I use.
And they don't specify the gear form, does that mean involute?



Don

 

[RocketNut]

Smallest Module? You type in the module size you want. I have used a module of .25 with out problems. As for the form there is two to select from. spur or helix (which most of my gears are) (both right and left hand) and you select the angle also. I found there gear design app to be extermly flexable and handy. Just wish I could use metric.

 

[Lew_Merrick]

I use RushGears.COM

And they don't specify the gear form, does that mean involute?

Don,

1) I go out of my way to avoid using Rush Gears as they have twice (back in the 1980's, mind you) sent me gears that did not meet their stated specifications after charging me a premium for the privilege.

2) All gear teeth are involute forms. The question is, which involute form? Unless you are making your own gear, this is not really an issue as the hobs or cutters in question will establish the tooth geometry -- not your design dataset. So long as the size (Module or Diametral Pitch) and pressure angle of the tooth match, the involutes will mate.

 

[RocketNut]

Here is a gear train I'm working on. All the gear models I got from Rush

 

[dwc]

2) All gear teeth are involute forms.

Watchmaking traditionally uses cycloidal gear forms, not involute.
These days many big manufacturers use modified involute as they continue to work well with larger tolerances than cycloidal gears, but the typical involute form of machine makers I have never seen. Apparently it is very difficult to machine pinions that don't break with a small leaf count with involute forms especially at modules around 0.065 which are not abnormally small in watchmaking.
Many of the small "boutique" manufacturers continue to use cycloidal forms just because the tooth form looks better and they are able to keep the tighter tolerances that are necessary.
BTW the largest module I use is 0.224 for the winding crown.
Don

 

[monafly]

For another gear generation program look at:
http://www.gearotic.com/index.html
This is from Art Fenerty of Mach fame. Lots of fun to play with and I've successfully imported gears exported as dxf's into Alibre so that I could further manipulate them.

 

[Leigh]

Boston Gear at http://www.bostongear.com offers a huge library of geometrically correct CAD drawings for all of their products, including spur gears and gear racks in both 14 1/2° and 20° pressure angles, worm gears and worms, bevel gears, etc.

You must register to access the site, then you must select a specific gear from the product listings in order to find the CAD drawings, which are available in all of the standard formats including STEP and IGES.

- Leigh