Inventor component rotation variable speed problem

[u238]

Hi to all....

 

I'm Using Inventor 2k10 Pro Suite. My main interest is gear design, all type of gears. I know Inventor has it's design accelerator, but I'm drawing better gears.

Anyway, I'm trying to animate a double-enveloping worm gear pair to mesh correctly.

 

In the assembly with rotational constraints it's going fine, but I noticed that gear pair loses the correct mesh as it begins to rotate in the Inventor Studio Assembly.

 

I checked the revolution ratios for 5 times an it is correct. Also I noticed that the problem isn't available when using gear ratios 1:1

 

Looking carefully I can se that the gear changes speed like this: 80% - 100% and looping this pattern for every revolution.

 

I also checked the acceleration a couple of times an I set it to Constant speed. The misalignment get worse if I set the acceleration to the default: 20-60-20.

 

Dunno it anyone understands me so here are some pic showing my problem.

 

Hope someone helps me

DE worm.zip

[shift1313]

First question. What are you trying to accomplish. Do you just want to see the gears in action? trying to render a presentation? Dynamic simulation will allow you to animate gears based on a torque input. You can get valuable data from the results like force, friction and so on. This is all based on contact. When using rotational constraints in the assembly it has nothing to do with contact.

 

also..

 

in the assembly make your gears Contact sets as opposed to using the rotations constraint. This will give you a more accurate account of whats actually happening and the interaction between the gears. I do not believe contact sets translate into Inventor Studio though. However in the dynamic simulation there is a Publish to Studio function, but ive never used it.

[u238]

For now I'm trying to render an animation by means of Inventor Studio. Since I have an older PC (Dual Core 2.0 GHz; 2Gb RAM; nVidia GO 7300 @ 128Mb) it takes forever to solve the contact sets. Rather I'm using rotations constraints coz I don't need any analysis, just want to se them in action.

 

I know it's a barbaric way, but I'm using tangent constraint to get a tooth to tooth contact. Than I apply the rotations constraints and remove the tangent constr. If for some reason the tangent constraint isn't working I just eyeball it.

 

Anyway, the worm set I'm trying to animate has a ratio 40:1. When correctly constrained in the assembly it looks fantastic, the gears are in a perfect mesh and don't lose their alignment.

 

The DE_worm shows the manual rotation in the assy - works fine

the IS_bug shows the variable speed on a 1:1 ratio gears animated constraint-less in Inventor Studio (hope u see the acceleration and deceleration) the speed should be constant coz no acceleration is applied.

 

Please, help me I'm really desperate....

DE_worm.zip

IS_bug.zip

[shift1313]

i believe it just has to do with the speed and steps of everything. I have animated gears before in the manner you are showing and it did the same thing. Try playing around with the amount of rotation and frames per second and see if it doesnt get better. It will make your file much larger though. On the output tab of the render animation box you can change the frame rate and anti aliasing. I dont think its an issue where they are actually skipping or loosing the ratio but i think its an issue where the gear ration vs the frame rate is a little off so it appears that the gears are speeding up until one point where they "reset".

[u238]

Well, at least now I'm not the only one having this problem I'm wondering if this bug is happening in Inventor 2k9?!?! Anyway, coz I don't have much time to render animations from studio i managed to do that in the *.ipn - Inventor presentation, but I'm recording to wmv by means of FastStone Capture since the built in recorder sucks.

 

Is there any way to increase the Inventor frame rate (Options/Display - to poor ....is there any more accurate setting)!?

 

Thank you for ur Help!!!!

[shift1313]

Not that I know of but I dont animate things very often. When you are moving your gears around you can set the rotation amount/time settings. For instance instead of 1 revolution in 5 seconds, make it 1 revolution in 10 seonds. Then when you set your frame rate to a higher frames/second it will be a smoother setup(maybe). Im just guessing here:)