Fusion 360 GEARS GEARS GEARS!

hey this is Rob and I'm going to show you some things about gears in fusion 360 first thing is how do you create gears then the second thing will be how do you how do you space them apart so that they the teeth actually mesh properly and I'll also show you how to put a few of them together to make something like a gear train and then I'll show you how to make them actually turn and move at the in the right ratio so that they actually look like they're working on screen and we'll do that using a motion link so the first thing is how to create gears there isn't a command if you look around you'll see there isn't command for creating gears there's no gear generator necessarily like there is in something like Autodesk Inventor but we do have a couple other methods one is to use an add-in that was that that's part of fusion 360 it's got a couple of quirks maybe a bug and out but it works and so I'll show you how to use that first I'll show you how to use the other method which is to just insert from the mcmaster-carr catalog so we just type in spur gears in the search field and here we have category 4 14 and 1/2 degree pressure angle gears so that that is one characteristic of gears that we care about some others are the pitch diameter which is really important we're basically using that to determine how the gears mesh together and then the outer diameter which is the overall size of the gear from one the end of one tooth the end of the other side then the other important piece of information we need is the number of teeth so this particular gear has 16 teeth 0.5 inch pitch diameter 0.5 6 inch overall outer diameter I'll click on that part number twos the CAD I con and then as long as this says 3d step I can hit save and it should import it as a component so see here in the browser it's good it's actually the name of that component is actually the McMaster part number if I'm okay with where it's sitting I can just hit OK here and I'll right click and swipe up to repeat that command and I'll do the same thing just type spur choose that category and this one will be 24 teeth point 75 inch pitch diameter 0.81 outer diameter i'll choose save and it's created a second component see a different part number here now hit okay so they're sitting on top of each other and the first question is how can I get them to be spaced apart at the right distance so I'll right-click on that bigger gear and move it over a little bit I could sort of eyeball it but that would be a bad idea so you know actually I'll cancel this first I'm going to change my units to inches since everything's so far and the catalog has been inches and I'll do that same thing move I'll drag it over and I want this number to actually be some formula that formula is pretty simple it's just the pitch type of the pitch circle diameter of the first gear divided by two plus the pitch circle diameter of the other gear divided by 2 I hit OK so you can see there you're meshing properly here and I think you know this may be a good time to show you actually if I if I activate that first component this smaller gear I can create a sketch on this gear face and what I'll do is I'll hit C to create a center point circle and for the the diameter here I'll put in the pitch circle diameter that we caught from mcmaster-carr I'll click actually I'll make another circle too so I'll hit C again and this one will be the outer diameter that mcmaster-carr gave us so you can see the outer diameter is I'll click on these two and make them construction lines you can see the outer diameter is just what it said it's kind of the edge of the gear and then the pitch circle diameter is you can see here it's actually like where these two teeth touch is right that it meets right at that pitch circle we don't need this I just want to show you that as a demonstration I'll hide those sketches and activate the route component again and so now what we're interested in is how can I you know maybe it's fine that these are parallel and just kind of horizontally I just moved it over in the x-axis but maybe actually it's supposed to be up here 45 degrees from where it is so I'll show you how to do that if you right click on it hit move and try and rotate it obviously that's not exactly what we want so I'll hit escape and do that again what we need to do is to say it should rotate around this point so I can hit set pivot here and instead of trying to find the center point of this gear which is a little tricky I can just choose any of the circles of the gear so that circle works as a pivot point or pivot and then I'll hit the check mark here that's really important so once you've once you're done setting the pivot point that check mark is gone you can rotate and you'll see that it's rotating around the gear and it's still the correct distance so those gear teeth would mesh I can see if I make it 45 degrees off from where it was those teeth still fit together but if I do 40 degrees they don't let's just leave it at 40 degrees and I'll show you how to fix that so I'll hit OK and what I can do is just rotate the smaller gear and put in that same number 40 degrees so now they they look like the mesh again so I think that's about it for showing you some of those details the pitch circle and getting these to be spaced apart and also how to put them at an angle I'll hide these too so I can show you the other method of creating gears you go to the add-ins menu choose scripts and add-ins and you can either find it under the scripts tab which means if you were to click it you can click any of the three they're just written in three different languages but they do the same things if you hit run it'll run that command you'll see the dialogue pop-up and it will create a gear and then it'll disappear if you choose add-ins instead when you choose one of these add-ins and hit run it actually sort of installs it and it stays running until you quit so you can see here this little circular logo or icon means that it's actually running right now so what that means is they add in actually created a create spur gear menu command here so I'll click on that diametral pitch was not one of the pieces of information that McMaster gave us so but I do have some of these other pieces of information so let's let's try filling those in so I know this was 14 and 1/2 degrees for the pressure angle I know it was 16 teeth and the gears this doesn't really matter here one of the quirky things okay so there's a couple of things that aren't so great with this this add in one is that you could put in a parameter here so for example pressure angle could be actually something called pressure angle if you created a user parameter with that value fourteen point five in it but when you create the gear it'll it'll sort of respect those values it'll create the gear using those user parameters but if you go back and change those user parameters later the gear won't change so it's not really parametric it's just allowing you to put and put of those user parameters in here for that that one-off creation of a gear so that's you know it would be great if that worked it doesn't work so the other thing is for whatever reason you can't put a user parameter here in for a number of teeth so that's a little annoying so you have to put a number here and then the final thing that I've found that's kind of tricky is that you that this field for whatever reason diametral pitch only accepts centimeters and normally you can get around that by putting a value in here and then multiplying it times one centimeter but that doesn't seem to work either so the only thing I've found that works is to actually just put in a you know an inch value and then multiply up times two point five four so that's what I'm about to do but first the diametral pitch is not one of the values that we got from that table and McMasters catalog so how do we calculate it the way that we do that is a number of teeth divided by the diameter of the pitch circle so that was 0.5 and how again multiply it times two point five four to get centimeters so this is the diametral pitch in centimeters if I hit OK it creates a gear and if I unhide that mcmaster one you can see they're the same size so that worked I'll do the same thing again create spur gear and that bigger one still had 14.5 pressure angle the number of teeth is 24 and then here again I'll have to say 24 time I'm sorry divided by 0.75 times 2.5 for and I'll hit OK so there's my bigger gear and if I unhide the McMaster gear looks like they're the same so that worked out now if you look you know I'll do the same thing I did before I'll move this over and I'll use the same distance which is 0.5 divided by 2 plus 0.75 divided by 2 it's moved them apart and they're the right distance apart but these teeth don't look like they mesh so you know if I wanted to if I wanted to look like they do which I probably do even though they are the correct distance apart and would in fact mesh if in real life maybe this is a little unnerving to me to see them smashing into each other here so all you have to do is rotate it I think by just 360 divided by the number of teeth in the smaller gear and I hit OK then they look like they mesh now I guess the last detail is if I hide these two gears if I were to just create a gear from the add-in and I didn't know some of these values it's worth knowing that you can calculate these so one is how do we ok so let me say this another way let's say we just take the defaults here I'll hit OK and creates a gear for me so given so far I've only got the diametral pitch and I've got the number of teeth so if I wanted to do this same thing that I did before and create a sketch I'll activate this new component I'll create a sketch and I'll hit C to create a center point circle how where's my where can I find my pitch circle and where can I find my outer diameter circle so that can be calculated and to get the pitch circle it's just the number of teeth divided by the diametral pitch which was 7.62 I think in that example oh but we're in inches aren't we so I suppose we'll have to do the opposite here and maybe divide this by 2.5 for o x 2.5 4 so there's my there's my pitch circle then we can create the outside diameter circle so that's C again to create another that's another center point circle and the formula here is going to be n plus 2 sorry and it's time looking at the actual formula but it's the number of teeth so that was 24 divided by 2 plus 2 24 plus 2 divided by the diametral pitch which was 7.62 of course we're back to this problem of it being in inches so I'll just multiply that times 2.54 so they remind to two circles that I might be interested in so that's it that's basically I just want to show you how you can find those values without actually having access to them from the from the mcmaster-carr for example so the last thing we show you is how to create a sort of gear train and let's say that I want the these two mcmaster-carr gears but I actually want four so I'm going to make a copy here and I will paste on the root component I'll paste new there's no reason why I'd want them to be linked to each other so I just created it as a totally separate component and I'll do the same thing here for the larger one I'll copy and then I'll right-click on the root component paste new and that one over as well so I just drag them over to be spaced apart what I'd really like is for these two years to be and this kind of arbitrary but this is actually what I'm trying to do myself so I'll give you the requirements I want these two gears to be horizontally they're going to be parallel to each other just like they are now or on the same axis this direction and then between them will be these other two years so I've got a large gear a small gear another small gear and then the large gear so how do I do that it's kind of tricky if you should start moving them around especially if you want to make a change to the orientation of any let's say these smaller gears you know you want to change where they are then everything has to get moved again it could get really complicated so the system that I've came up would come up with this kind of a workflow I guess for create you can create a sketch and then base the position of these gears on the sketch so let's give that a shot I'm going to actually hide these gears that I've just made and I'm just going to create a sketch and this sketch I'll just I'll create a center point circle with the C key I'll create this one at the pitch circle size of the smaller gear I'll do the same thing here for the other small gear do the same thing here but for the bigger gear and the same thing again for the other bigger gear so I've got my four gears and there are a couple things first I say that these need to be directly across from each other so maybe what I'll do is create a line between them between their center points I'll click on it and hit X to make it a construction line and I'll add this constraint by right clicking I'll add a horizontal constraint so now they need to be kind of directly across from each other I could also add a dimension here and say that this distance between them should be one and a half inches or let's go with one point two inches now how do I get these other gears to kind of mesh properly we've already said that the way to get gears to mesh is to have their pitch circles be tangent so I'll click on that circle and that circle I'll right click and say that they need to be tangent I'll say let me move it over make that a little easier I'll say that this circle and this circle right click they need to be tangent and this circle in this circle need to be tangent so I'm creating this gear train where the skier connects to this one connects to this one connects to this one now if I start trying to move them around you'll see they all stay together so it could be that there's some they're different orientations you know maybe the distance here the distance here in this case always has to stay the same if I remove that dimension you'll see that you know they can they have more options for the way that they move or you know another thing that we could do is we could add the the outer circles here so the outer Demeter's so I'll click here and I'll say the outer diameter of this gear is I think points 0.81 it came from McMaster and I'll do the same thing here point eight one the outer diameter of these were five six well you know I don't even need I'll undo so I guess the point I was getting to it was maybe you actually care in this case about the outer diameter and that you don't want the the gears to extend past a certain rectangle for example so here's my rectangle I could say that this should be tangent to the rectangle and and so should this side so this way you can make sure you know beyond the the pitch circles which determine how these gears actually mesh you can also tell how far the gear actually extends in real life so in this case I want to make sure that the ear the whole gear train lies within this rectangle for example and then of course I could add a dimension here so that really I only have to point one inches to work with so now my gears all adjust right so that everything is still within that that rectangle so let's let's go back a couple steps so I did you know I don't really care about this rectangle I just want to show you that that's possible I'll leave it there and I just won't have the I think maybe it's worth going back a couple steps to just get rid of the rectangle and I'll get rid of the outer diameter circles too main thing we're concerned with here right now is just how can we get this get the gears to now match up with the this this sketch that I've laid out I'll hit stop sketch turn on my gears that I made and they're not obviously they're not in the right place so the way that I can do this now is to use the modify menu and choose align I'll have to I don't want to align components which I think might be the default this is a component the gear is a component these sketch circles are not so to include the sketch curves I would have to choose this align bodies sketches and I don't know what the ellipse means there I guess 100 I don't know but but we are interested in aligning these bodies these bodies that are part of the component with these sketch curves so what I'll do is I'll choose and this can get a little tricky right now as far as selecting these things I'll choose this component and I'd like to choose its center so I'll just cover over that circle I'll choose it and then I'll turn the sketch back on and say it should be aligned with that center point should be I'll just keep doing the same thing so that should be aligned with that and this circle should be aligned here oh it's possible that I didn't okay so I've got a little problem in that I actually did a paste instead of a paste new I think for these gears so they're they're connected to each other I think rather than fix that I'll just let's just say that's the problem and now you can see at least how yeah you know I guess I should fix it so I'll go to modify a line and you'll get a second look at this now so I'm not I'm aligning that with this hide the sketch so I can choose this circle and align that with this center point I'll do the same thing out here align this center point of this circle with this sketch curve and the last one so there you go you know the teeth are not aligned and I suppose that could be kind of tricky but I think it's more important that these are spaced apart correctly in my case it is anyway I'm not so interested in this I think I would at this point just kind of fudge it so that they look like they're I could rotate each of these gears so that they look like they're the teeth are meshing so you know just flying around until I find the right values to make it look like they're meshing and that way it would it would look better in the drawing but really what I'm concerned with is the distance between these now the nice thing is since those sketch curves weren't constrained in space I can move them around and in fact I don't know if you know this but even though I'm not in the sketch I can move them around so you see here as I move them around they still are maintaining those constraints the tangent constraints of course it would be great if that align command kept these two aligned they doesn't but it's not that hard to just go back and realign these so I can show you that now if we just go back to modify and align I can choose this gear and realign it with that circle you can see that I'd be able to adjust and move the gears around and not have a whole lot of calculating to do so the very last thing I want to show you is how these these gears can look like they're meshing so in this case you can see I've got two gears that I brought in from McMaster car I made it kind of a base for them with these axles sticking out and I created revolute joints between this gear and that axle this gear and that axle if I right click and choose drive joints normally this this gear would just move on its own but you can see it's causing the other one to move as well and it's moving its meshing correctly so even though this gear is bigger than that gear so if we look at this motion link you can see how I did it and and so there's a formula here right like basically for every 360 degrees of rotation in the smaller gear this second gear should rotate less this gear will will be slower than that one because that's the nature of gears so for every 360 degrees of rotation here there should be three Hun one-sixty it should be less than 360 for the bigger one so that means 360 times this fraction is going to be a fraction of 360 right so the way that I got these values is of course the number of teeth in the small gear number of teeth and the bigger gear I didn't have to put in one degree here so it's it's just basically 360 times in parentheses the teeth of the smaller gear divided by the teeth of the bigger gear and you can see from the animation that they are moving at the right speed so this one on the left goes faster than the one on the right and and of course if I don't click reverse then they are not doing what gears do in real life they're moving in the same direction so I'll have to also choose reverse that's about it I think I've shown you everything that I've learned in the past a couple days since we're trying to do some things with gears let me know if you have any questions or you think I should add anything maybe I can stick something on to the end of the video thanks good luck

Channel: Rob Duarte

Views: 122,262

Keywords: fusion 360

Id: KbhSQZ236EE

Length: 22min 43sec (1363 seconds)

Published: Fri Jun 10 2016