Spur Gears in Fusion 360

okay so this is going to be a quick tutorial on how to use gears for simple projects in fusion 360 I just did quick caveat I'm not an engineer and I don't totally understand this stuff but I know it well enough to use it for projects I make myself and it seems to work pretty well for me so um I'm gonna go through what these things mean and how to sort of put these things together to use gears and a project you might be interested in doing so the first thing you're gonna do when you're in fusion is go over here to add-ins and then go to scripts and add-ins and then you want to go down to spur gear either one of these will work they're just different kinds of scripts and these come with with the program so we click that one and click run this is the dialog that comes up um so I'm just going to run through this and show you what what things mean and so far as I understand them so the first one is uh the standard is metric so I'm just I use metric for pretty much everything for smaller projects anyway so I just stick with metric with that it makes things a little easier the next one is pressure angle you'll see you here you've got three different options for that the the pressure angle basically it's see I've so here it gives the direction normal to the tooth profile so it's like the yeah the angle where the tooth is pushing the other tooth okay they're the standard values are 14 and a half 20 and 25 20 is the default here and from what I understand that's the most commonly one used what from also from what I understand lower pressure angle that will give you less noise also less horsepower and then higher pressure is the opposite so it's noisier but it also gives you more horsepower so let's just go with the defaults here and see what we get so that's 14.5 for the pressure angle and I just I didn't change anything else okay that's what that gear looks like I'm gonna do it again let's change this to 20 and you'll see what changed here is that again that pressure angle changed right so this is the one that was 14 and a half and then this one was 20 so that angle right there is is steeper right I'm sorry it's not steeper it's it's less steep right a shower and then if we do that again change it to 25 this is going to be even shallower right so it's a more of a gradual angle so again higher numbers apparently need to hoard more horsepower so I'm guessing that's that means you've got more surface area connecting somehow but in any case the default has always worked for me for the projects I've done so I'm just gonna undo get out of those all right so back to this okay so we talked about that the next one is module so the module is the unit of size that indicates how big or small the gear is it's a ratio of the reference diameter divided by the number of teeth so think of this as like a multiplier that's gonna tell you how big the gear gets right so you can see here that it's calculated automatically basically so the module when that's set to 3 and the number of teeth is at 24 you get a 72 pitch diameter then going down to the bone skip over for a second the pitch diameter is basically it's the distance at which the gear will meet a corresponding gear and it's calculated automatically so you see here the pitch diameter that's sort of somewhere halfway down the tooth same thing with this bigger one and that tells you where those two are supposed to meet that tells you the distance the center distance between the two that's how you calculate that right so let's see what happens if the module is set to twelve point seven by default I've got 24 teeth then that's the pitch diameter I get you'll notice I can't change that right that's that's calculated automatically I change this to twelve you'll see that was about that's that's half the size maybe exactly was it exactly emphasized yeah it's exactly half the size so it's important I mean you can you can do as many different numbers of teeth as you want right I can make this 36 I know that if I keep that module the same these will work with each other okay and that's that's important so that's a really big gear for what we're doing so I'm gonna stick to three for that and then 24 that's 72 that's fine right okay the backlash is basically think of the backlash as tolerance between the gears it's like what do I have here it's thought of as the tolerance between the gears it's the gap between the tooth that's closed when the gear reverses directions so it's like a little bit of a space between them and you know if you have like a zero tolerance gear that'd be a really hard thing to make with a 3d printer but I guess it's possible but anyway it's usually a good idea to have a little bit of a little bit of a tolerance there the defaults point one five the route fill it radius that's the radius where the tooth meets the meets the the route okay so it's the radius at this point right here if that radius is bigger you're basically gonna have a stronger tooth because it's connected more it's got more more purchase on that on sort of the center of the gear but if you make it too big the tooth won't fit in that hole and you'll probably get an error if it's too big I don't think it lets you do things where the gears won't actually mesh that looks way too big to me so I'm gonna go with 0.75 it seems to have worked pretty well before and then over here your thickness that's just the thickness of the gear right that's something that's easy to change later on when you make this part that's kind of a weird number I think I think 11 is what I want to do using these bearings I'm using and then the whole diameter is that's just the the hole in the middle again you can kind of change that thing later but let's just give it a round number call it six if I click OK there we go so now I've got this gear it's 24 teeth it is 11 millimeters thick it's got a three millimeter radius hole right there and this green line is the that's the pitch diameter so it gave me this line and turned it on so now I can see exactly where this is supposed to meet another another year and see right there the radius is 36 that's going to be useful for me in a second okay so let's say I want to make a couple of gears mesh together that are a two to one ratio so if this is 24 teeth I mean I need to make one that's 12 teeth so again I'm gonna do the scripts and add-ins go down to spur gear run you'll notice all these all these um values stayed the same from last time it's a good idea at this point to do something like this so I'm gonna take a screenshot of this so shift command 4 and a Mac and then I hold down the spacebar and it's gonna grab that one for me so now I have that and I can refer to that later because it doesn't really say that information as far as I can tell so okay so the only thing I'm gonna change here is the number of teeth I'll change that to 12 that'll give me a 1 to 2 gear ratio you'll notice when I hit tab to get out of this field the pitch diameter stayed the same that doesn't seem right okay oh no okay that's fine yeah it's half of that sorry I was looking at a different number so the radius here is 36 right radius here is 18 it tells you the diameter which is a little might seem a little bit confusing but when you just click on anything in fusion it gives you a little heads-up down here in the bottom right corner to tell you what the value of it is so this is giving you the radius that's or the default thing so this obviously 18 is half of this and that's what we'd expect because all the other all the other parameters are the same and these are this one's 12 teeth this one's 24 okay so these are gonna come in automatically on top of each other at the zero location right the distance between these the position of these gears is going to be the radius of this right the diametral pitch so that is 18 the diametral radius I got and this is 36 so this one one of these anyway needs to move over by the radius of this plus the radius of this so that's 36 plus 18 so I'm gonna right-click on this component over here in the browser that's just how I like to do it it's a million different ways to do it but that seems easier for me right click move copy then I'm gonna move this axis over like in type 54 36 plus 18 or I can do 36 plus 18 if it's some weird number and I don't haven't done the math in my head there you have it okay now the other thing you would want to do here is to position this the proper way I'm gonna click on that right click move copy it's centered by default and that's fine but I'm gonna go on rotate over here and I want to pick an axis so I can pick that cylinder right there and kind of look around okay and then it is let's see so it's 12 positions divided by 36 oh I think we need to do 15 you basically just move it until so we know that's an even number 36 divided by 12 divided by 2 should give you 15 right because it's yeah cuz you're good you've got two positions there's a throat in the tooth so anyway you can just kind of eyeball it right you look in here and say okay I know I've got an even number I know I've got to rotate this thing so that it's it's one position over right so minus 15 or plus 15 doesn't matter there you have it okay so now you have two gears that are meshed with each other let's give it a base so I'm just gonna click on X I'm gonna do a new component good practices I'll call this base I'm gonna do a create sketch look at the top and then just click on that always capture position because things will move move around if you don't I'm gonna do a circle whoops sorry I want to do the center circle from the origin point to click on any one of those points there so that's like the the extent of the year I'll do another one either circle that middle point to there then I'm gonna make like I'll make sort of a egg shape here so I'll do a line like that and then another line over here tangent this is kind of arbitrary you don't have to be this precise about this stuff but I'm just making a shape where it gives me this little background shape that looks pretty good stop that sketch and I'll go to the underside through this just picking all those profiles minus-6 just got an arbitrary number okay so now we got a base go back here and activate good time to save and now what I'm going to do is give myself some some joints to to work with these things joints are basically they give you a preview of the way that things will move right so I take this gear and move it like that I can just kind of drag it anywhere I want I'm gonna give myself a I'm gonna make it I'm gonna constrain it to the base so that it moves like it really would in real life so to do that I'll go to assemble and then I'm gonna do as built-in joint it's a different kind of joint right so I click that the type needs to be revolute I'll click on this gear and this base and then it wants an axis alright so then I can pick any circle that is on that axis so I could pick this one or this one that's fine and now you'll see it's giving me a preview that it's rotating a certain way click OK and I'm gonna do the same thing over here I so I do another asbill joint that to that with this is the axis there we go so I should be able to grab these and pull on them and they should be able to rotate but that doesn't work because you'll see the base is moving to the reason for that is that the base isn't grounded we need something here in the model to be grounded otherwise everything will just move freely click on that right click ground I can click and move this gear and you'll see it turns let me do the same thing with this one alright cool ok so normally with any other kind of linkage like this you can do something called a contact set and what that does is gives you like a real preview of of like the physical interactions between things that can be kind of tricky to get right and I don't really recommend it at this stage and anyway for gears it gets really really bogged down in terms of your processor like it's get calculating all these little points where the surfaces come together to turn so I'm going to show you a quick trick to make it look real and actually give you a sense of positioning and like the way things will move in relation to each other ok so I'm gonna do a motion link between this joint and this joint you'll see by default they're both going positive 360 well that's not how it worked right one of these definitely is negative because there cuz it's got to turn the other way and one of these is moving half as much as the other so you could just do this like one degree here is 2 degrees here so this does two turns for every one turn over here and that will give you what you need click OK and now if I turn this I'll see you my other ones turning same thing over here turn and turn there you have it yeah so that's basically how you do gears and then in the video is following this one and instructable I'm gonna show you how to make indexing gears and how to integrate these with some skateboard bearings so you can make all kinds of a project

Channel: Jonathan Odom

Views: 192,625

Keywords: gears, mechanics, design, engineering, meanufacturing, autodesk, fusion360, make

Id: ZakT54JIhB8

Length: 15min 29sec (929 seconds)

Published: Fri Sep 08 2017