Will Gear Relations work on miter and bevel gears

david_sohlstrom

I have an assembly that will have several miter and bevel gears can I use Gear Relations on these gears so I get the part rotation I need.

Dave

jakeramsley

Revolutes are mates that restrict all degree of freedoms except for spinning around the blue/z-axis of the mate connector.  A gear relation is just a relation between two revolutes.  It's essentially saying that when the first revolute goes around once, how many times will the second revolute go around.  The revolutes can be as arbitrarily defined as you want.

While they are named gear relations, they can be used for any revolutions you want to tie together.  One of our interns constrained some parts that would change from one kind of polygon into another based on rotations.  It's just natural that two revolving things would be gears so we named it after that.

jakeramsley

If you set up the revolutes correctly, yes they will work.

david_sohlstrom

I saw revolutes in the drop down  but I'm not sure what that is.

Dave

jakeramsley

Revolutes are mates that restrict all degree of freedoms except for spinning around the blue/z-axis of the mate connector.  A gear relation is just a relation between two revolutes.  It's essentially saying that when the first revolute goes around once, how many times will the second revolute go around.  The revolutes can be as arbitrarily defined as you want.

While they are named gear relations, they can be used for any revolutions you want to tie together.  One of our interns constrained some parts that would change from one kind of polygon into another based on rotations.  It's just natural that two revolving things would be gears so we named it after that.

brucebartlett

@David_Sohlstrom12345 check this part out. It has 2 revlote mates to position the sprockets and a gear mate to link at the correct ratio. I have not worked how to model the chain yet.
https://cad.onshape.com/documents/46b17dd88ed24f55bca2eb69/w/81cd48206e74495eb7d7dee1/e/76a995401969499bb4ca52df

david_sohlstrom

Making chain will be fun.

Dave

Ben_

@BruceBartlettwould a slider mate on the chain elements and a rack and pinion mate to one of the links work? Well at least a partial rotation may be possible this way

Here is a experiment I dinged out. It should work for a partial rotation. 
https://cad.onshape.com/documents/ebc649b6ae564e4ea7a04da7/w/11725af34d624fc29c56faa7/e/8b01e07502c74ea38472eae8

The big thing here is figuring out how to not get into mating hell by making a chain and joining all the links. It would be nice to be able to pattern not only the part but the mates of a part in a chain and link array.

Sad thing is that I likely will go and make a chain to work with this to show it can be done. UGH! A curious mind can be a massive OCD time suck some times @BruceBartlett what size of chain will work with your sprockets? 4L, 5R, 6N, 7N?? At least I am sure I could find the models for the links

brucebartlett

@Ben I will share you in and you can go for life.
It 1/2" chain, I attach the spec sheet in the doc.

also a good branching, test

david_sohlstrom

@BruceBartlett  and @Ben  When You crack the chain problem move on to timing belts. I'm thinking a lot of people would like to know how that could be done.

Dave

john_f_carr

There is a video introduction to gear mates: https://www.onshape.com/videos/whats-new-gear-mates.

david_sohlstrom

Well I watched the video a couple of times and that helped. I did a test assemble and got things rotating. The only problem I am seeing is that the gears do not mesh correctly. They are tooth to tooth and not tooth to valley. Any ideas.

Dave

Ben_

The mate starts with the mate connector triad. If you create a new mate connector but rotate it on the z axis the right amount the gear then meshes. Clear as mud?

david_sohlstrom

@Ben  That worked thanks

Dave

david_sohlstrom

@BruceBartlett I see you have some chain added to your "Drive line components" project. Did you get the chain to flex

Dave

Ben_

I know it will work it is just a 'make time to model it' situation

andrew_troup

As a mechanical engineer, I love electro-mechanical devices like variacs, partly because I can fix them when they break. They wear their heart on their sleeve in the way they "show their working".

(In theory, I should love relays and solenoids too, but in practice they often seem to let me down, so I've learned to avoid them when I can). 

So one thing I've always wanted to try is to wire up two stepping motors in parallel as peer devices, with no external electrical power source, say for manual remote actuation of a (low torque) rotating device, or for remote indication of the attitude of that device, or both.

I mention it here because it's the purest analog I can think of to a "Gear relation".

david_sohlstrom

The hard part is going to be getting the electrons to flow through you CAD wires from one stepper to the other and stay in phase.  

Dave

brucebartlett

I've given up on a flexible chain @David_Sohlstrom, I will see how @Ben goes. However I have just included a screw feature using the new mate's (Screw Relation). Also Found that ref. dimensions (change to driving dimension) have been added, I think I am more excited about the ref. dimensions than the screw mate. I also used the new offset on the fasten mate to get the bolt head in the right spot against the sprocket face. 

Public doc https://cad.onshape.com/documents/46b17dd88ed24f55bca2eb69/w/81cd48206e74495eb7d7dee1/e/76a995401969499bb4ca52df