topic Re: Question regarding Gear Pairs in Mechanism in 3D Part & Assembly Design

Question regarding Gear Pairs in Mechanism

dayoub — Sat, 12 Dec 2020 14:59:03 GMT

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

Re: Question regarding Gear Pairs in Mechanism

TomD.inPDX — Fri, 22 May 2015 15:05:57 GMT

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.

Re: Question regarding Gear Pairs in Mechanism

dayoub — Fri, 22 May 2015 15:20:48 GMT

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.

Re: Question regarding Gear Pairs in Mechanism

TomD.inPDX — Sat, 23 May 2015 01:25:17 GMT

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.

Re: Question regarding Gear Pairs in Mechanism

TomD.inPDX — Sat, 23 May 2015 06:44:09 GMT

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.

Re: Question regarding Gear Pairs in Mechanism

TomD.inPDX — Mon, 25 May 2015 06:51:36 GMT

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...

Re: Question regarding Gear Pairs in Mechanism

dayoub — Wed, 27 May 2015 14:40:55 GMT

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.

Re: Question regarding Gear Pairs in Mechanism

TomD.inPDX — Wed, 27 May 2015 16:11:15 GMT

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.