Gears with Spur Gear tool

[Anonymous]

Hello

I'm trying to figure out how properly create and measure center distance for two gears one 12 tooth and another 25 tooth with 3 mm tooth spacing

Seems like I should learn more about setting in Spur Gear tool design gear mechanics.

Here is model to illustrate what I'm trying to do:

[WHolzwarth]

I found it here:

https://woodgears.ca/gear_cutting/template.html

Getting the center distance can be calculated like this:

Pitch diameter = Tooth spacing x Number of teeth / Pi

Center distance = (Pitch dia 1 + Pitch dia 2) / 2

I can show this in Inventor, if needed

[Anonymous]

Hello,

Thank you for your quick feedback

Yes that's right, I did this example with this Gear template
generator just to show required gears.

I'm not sure, what I've missed there, it looks like I'm doing the same measurement, but I've design failure with Spur Gear tool, seems like by incorrect using. 

So, it would be very helpful, if you can show, how to set this with Inventor Spur Gear tool settings for required gears.

For example 29 tooth to 12 tooth with 3 mm spacing, like this:

with Spur Gear:

[WHolzwarth]

Here's a set (2018 files). I didn't use a tooth spacing of 3 mm, but module=3 instead. Module sizes are standard values.

Two remarks:

1. Normal Inventor gear models are simplified. The real shape can be modeled for spur gears by Export tooth shape. You can see the difference by looking at the colored parts.

2. Small teeth numbers (<14)  result in undercuts of the tooth shape. You get a red message, but it can be changed by selecting another Unit Corrections Guide: With Comp. of Slips. Try it, and see the difference in shapes.

[3D4Play]

Yes, it will be helpful to understand better the terminology. You are looking for the center distance, given diametral pitch and number of teeth. So, start the spur gear design accelerator, and select the design Guide example of "Center distance". Set the Diametral Pitch to 3, and the number of teeth for Gear 1 and Gear 2 to 12 and 25, respectively.  Click "Calculate" and see the result. The result assumes a 20-degree pitch angle. I hope this helps.

[Anonymous]

Hello

Thank you for your answer and example, it is very useful

In assembly I've two axis in mechanism, I've used Design Guide: Module and Number of Teeth with Gear Ratio 2.8000 ul as Component for both, in this case gear 56 and pinion 21 tooth, here is a setup:

Then after selecting Cylindrical Face and Start Plane, gears and connection are created by the program, I've Export tooth shape for both parts separately with giving of same tooth number with circular pattern. Here is difference before and after, same as in your files example:

Now, I'm trying to figure out, if Spur Gear tool allows to complete job in assembly, what is a proper way to use and edit gear parts in assembly with keeping connection, or it should be done separately out of Spur Gear tool.

For example if gear is separate part and rotates independently on its own shaft in assembly. But pinion must be attached to another part shaft, on which it was created, rigidly, to rotate part with it.

Another question is how to keep exist gears connection with new Export tooth shape parts in assembly. It looks like I can't just overwrite exported files to Design Accelerator folder.

Or I have to use Joint and Constrain for both of this tasks after, let's say like in this example

[Anonymous]

Hello,

Thank you for your feedback and answer

I want to use exist fixed axis points in mechanism for gear and pinion, which distance can't be changed. So, I use Design Guide: Module and Number of Teeth, as described in replay to Walter Holzwarth below. But also I'm not sure, what is a appropriate way in my case to change number of tooth for gear, if I want to use selecting Cylindrical Face and Start Plane

[WHolzwarth]

Let's try a description:

- In an empty IAM, load a Spur gear placeholder.ipt and ground it versus the origin planes (Axis pointing in z)

- Place a copy of this part flush to it on the YZ plane. XZ plane seems to be not working because of pre-defined iMates

- Set a Mate constraint between both with a random distance (here 30 mm) as a starting position. Later this random value will be replaced by the Center distance

- Start Spur gear generator. Set m=0.6, z1=21, z2=59, Facewidths 3.9 and 3.65.

- Set Unit corrections Guide to User, Total Unit Correction to 0, and Unit Correction 1 to 0

- Click Preview and watch Teeth mesh. That's the perfect look. You can play animation at the bottom line

- But calculation shows no match in center distance. Now change the above Mate of 30 mm to 24 mm. Calculation still shows error

- Now a point that many users don't know: Switch to Calculation tab, and change Power to 0.01 kW instead of 1 kW. New calculation shows no more error. But initial Power setup was too much for this small set of gears.

- Next step is creation of perfect geometry. Export tooth shape for both parts, and save them

- Import both parts to existing IAM, and constrain them with Rotational joints to the existing gears

- Set a Rotation constraint between both pitch diameters. Ratio should be 21/59

- Switch Spur Gears invisible

- Now you're able to move both parts by mouse with matching teeth. see attachment.

[JDMather]

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@Anonymous wrote:

I want to use exist fixed axis points in mechanism for gear and pinion, which distance can't be changed.

---

This is critical information that somehow I missed in the original problem description.

Is the center to center distance actually 150mm?

[Anonymous]

Hello,

Thank you for your feedback

Sorry for this mistake in description about 150mm, it was basic example, and I've missed this value.

In mechanism I've two pair of gear and pinion.

First pair center distance, which can't be changed is 17.091 mm 6 tooth pinion and 27 tooth, gear ratio 4.5000 ul.

Anther should be 12 tooth for pinion with gear of 25-27 tooth, gear ratio should be about 2.2400 ul, in this case distance is not critical, diameter of gear can be changed, important is pinion tooth number 12

[JDMather]

Do any of these gears have to mate with existing gears?  (in other works, Pitch or Mode will have to match existing gears)

How/who will manufacture the gears?  Machined? Injection Molded? 3D Printed?  Purchased off the shelf???

[Anonymous]

No, all gears will be designed and does not requires match any exist gear or other parts

I've already printed 17.091 mm 6 tooth pinion and 27 tooth gear in two different materials which is Nylon X with Carbon Fiber and Taulman nylon bridge with layer thickness 0.1 and 100% infill

Seems like both material works fine with motor speed 0.07 sec/60° and 70 grams of required mechanism mass acceleration. I don't know how it will behave with longtime constant load, but anyway, when model will be done, I want purchase  metal gears, I'm not sure yet machined or injection molded

Any advice on all this tasks would be helpful

[lena.talkhina]

Hello @Anonymous  !

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