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Question regarding Gear Pairs in Mechanism

dayoub
1-Visitor

Question regarding Gear Pairs in Mechanism

Hi,

When defining a gear pair, you have to define the pitch circle diameters of both gears. In my case, the connection is a rack and pinion (simulating a pulley/rope train). However, when entering the pitch circle diamater in the gear pair dialog box, I seem to only be able to enter a numerical value. Is there a way to drive that pitch circle diameter from say the base design skeleton (in the context of motion skeleton assemblies)?

Thanks,

David


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7 REPLIES 7
TomD.inPDX
17-Peridot
(To:dayoub)

You can enter a user defined ratio.  In case of the rack and pinion, it want to know a linear distance per rotation.

I have run into some limitations in the rack and pinion where the servo axis has to be perpendicular to the rack.

Differential Drive for Micro-Manipulators

In this mechanism, everything is based on user input gear connections.

Yes, the pulley rotation axis is perpendicular to the slider axis I'm using for the rope.

Is the user defined ratio a parameter that I can drive using a relation? It seems to be simply another way of defining the gear pair. I want to drive that value from another skeleton via a relation.

TomD.inPDX
17-Peridot
(To:dayoub)

I haven't tried to find the parameters defined to user-defined gear ratios so I am not sure if it can be driven.

However, you should be able to drive the ratio based on a feature, and the feature can be driven by a relation.

Just not sure how many regens are required to get the new data to take hold.

I added a reply and it disappeared.  Something funny is going on with this thread.

Edit: ...and now that I added this post, the earlier reply showed up...

TomD.inPDX
17-Peridot
(To:dayoub)

I went back and looked for the parameter that connects to the gear definition dialog and could not find it.

It seems you should be able to select a feature to set the pitch diameter or drive the value with a relation... but somehow this is buried deep within the code.

dayoub
1-Visitor
(To:dayoub)

I ended up giving up, but now any time the gearing ratio changes, I have to remember to manually update the value so the mechanism still functions properly. Thanks anyways.

TomD.inPDX
17-Peridot
(To:dayoub)

If you have maintenance, you can submit a support case to have your question answered.  It may not be the answer you want but it will settle the issue.

In general, a change in ratios also requires a new analysis run.  I agree it should pick up ratios based on geometry or a parameter, but I cannot find how it is done either.

Please report back if you find something that helps.

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