GT2 profile

[Anonymous]

It is 2020.  I am using Inventor 2018.  What I want is very simple: I want a profile for a 60-tooth GT2 pulley.  It ain't rocket science.  The instructions for how to draw this from scratch are cumbersome.  I should be able to go to a design tab, say "GT2 profile", give a number of teeth, and have it give me a profile.  I can then bind the center point of this profile to where I want the center point of the pulley, and that should be all that I need.

I have found GCODE files that pretend to do this, but they have absurd restrictions.  For example, they assume that I want a 5mm or 8mm shaft, and a #4, #6, or M3 set screw.  No, today I need a 60-tooth pulley with a 22mm shaft and three #6-32 set screws at 120 degree angles.    I need another gear two projections that activate microswitches to limit the travel.  Without a complete rewrite of the GCODE, I have no hope of getting what I need. 

It is complicated by the fact that it takes 2.24 revolutions to cover the range I need, and to put the microswitches in, I need to go some odd gear ratios so that the third gear travels less than one revolution between the two microswitches.  This is my job.  The job of the tool is to create what I need.  I need to connect a continuous belt of a certain length so I need to model how this belt fits so I can position the shafts properly, and the idlers and tensioners appropriately.  Yet I don't see an easy way to do this.

Creating a GT2 pulley profile should take perhaps four mouse clicks and a couple keystrokes:

Create pulley (1 click)

GT2 (1 click)

60 (1 click and two keystrokes)

OK (1 click)

Now I can extrude this profile to get a gear as wide as I need; I can then create another profile so I have two belts on one pulley; I can put a 22mm shaft hole in place with another extrusion.  I can place set screws where I want them.  They can be whatever size I want.  I can use the setscrew drawings from McMaster-Carr.  But I can't see why I can't create any gear I want, down to 2mm shaft diameter, worm gear, bevel gear, whatever I feel like.  Why are there so many missing features and absurd limitations in a fundamental tool?

Also notice that if I want a 57-tooth gear, or a 49-tooth gear, or any other tooth count I want (117; 243; etc.) that I can get it, and not be restricted to somebody's limited imagination of 12, 20, 36, 60, or similar silly limits.  That's why we have 3D printers, so we are not limited by preconceived notions of what is appropriate.  I can build whatever I want for my purposes.  It is not the job of the tool to tell me what I can do; it is the job of the tool to take my specifications and create what I asked for.

[JDMather]

I think that all of this is built into Inventor.

What are the specifications of your belt?

[Anonymous]

This does not appear in any of the documentation for 2018, although I found a video that claimed to be showing this in 2011.  But it assumes that I knew how to get to the menu that let me design the gear and belt parameters, and after a couple hours of research, I was unable to discover how to do this.

If it is built in, it would be in the documentation.

The specs are a standard GT2, 6mm wide belt, loops of 200mm, 300mm and 500mm (I have an assortment); I need to model a 20-tooth 5mm pulley, and then compute another one that gives me the right angular-distance-per-step of the motor doing the driving, which 60 teeth is close, but other numbers might work better, according to my spreadsheet, which takes angular distance, gear ratio, distance to laser, and the mapping from spherical to cartesian coordinates into account.  Which is why I want to custom-3D-print the driven pulley.  In the second case, I need a ratio that changes a 2.24-turn rotation of the driven gear to roughly .75 turns of the limit-switch activator gear.  Exceeding the 2.24 turns rotation will damage the mechanism of the driven device, but with 16-step microstepping, I have the fine control I need within that range.

[Anonymous]

At least in the images I saw, there is no GT2 belt.  Inventor seems to think that anything smaller than a 1/2" shaft does not exist, whereas I am concerned only with 2mm-10mm shafts.  So it may not have anything at the scale I require.

[SBix26]

Inventor's component generator for synchronous belts does not contain the higher performance profiles developed by Gates (HTD, HTD II, GT).  The original trapezoidal profiles are all that's available.  Since these high performance belts and pulleys are widely available and widely used, I think it's a reasonable request to make for future versions of Inventor, but they are certainly not in there now.

If you create (or find an existing) an Inventor Ideas forum post requesting these profiles be added, place the link back in this thread-- I for one would certainly support that.

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Sam B
Inventor Pro 2021.1.1 | Windows 10 Home 2004
LinkedIn

[swalton]

I use the Gates Design IQ or Design Flex Pro software for detailed belt design.  Once I have a functional design, I model it in Inventor.  

See: https://www.gates.com/us/en/knowledge-center/engineering-applications/design-IQ-software.html

[Frederick_Law]

Download it from Misumi.