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dayoub1-Visitor
1-Visitor
May 22, 2015
Question

Question regarding Gear Pairs in Mechanism

  • May 22, 2015
  • 3 replies
  • 2745 views

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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3 replies

T
TomD.inPDX17-Peridot
17-Peridot
May 22, 2015

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.

D
dayoub1-VisitorAuthor
1-Visitor
May 22, 2015

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.

T
TomD.inPDX17-Peridot
17-Peridot
May 23, 2015

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.

T
TomD.inPDX17-Peridot
17-Peridot
May 23, 2015

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.

D
dayoub1-VisitorAuthor
1-Visitor
May 27, 2015

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.

T
TomD.inPDX17-Peridot
17-Peridot
May 27, 2015

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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