![]() I have no clue how they physically work, but the concept is simple. The first thing i need to say about SW gear reductions (AKA Harmonic Drives) is that they're basically magical. it was the right size, it just didn't have the reduction needed, and therefore not giving me the torque necessary to make a functioning robotic arm ![]() The problem is that I mentioned before that I needed 30-1, unfortunately after spending a couple of weeks working on this I had to scratch the planetary gearbox. I just made a cover to keep everything contained and that was it! a simple 4-1 planetary gear box. lastly I added the sun gear, which is what ends up being attached to the motor. I then made a housing to hold everything with screws. I then made 3 smaller gears using the same tooth profile, just less teeth as the planet gears. which can be found by clicking Shift+S and then scrolling down to find the Spur Gear plug-in.Īfter playing around with the backlash, and the number of teeth I used that gear as a cutter, to cut away from a circle leaving me an outer gear. To skip over the bring math bits, I first used the Fusion360 plug in for Spur Gears. Īnd I highly recommend you check his channel out. There's an amazing series on gears by Antalz. Since i had no idea how to design anything gear related in fusion360 I took to YouTube to offer me some guidance. Unfortunately the cycloidal gear reduction would've been too expensive bearing wise so I had to forget about using those. Most of the parts need to be 3d printable, and I wanted the cost to be below 30 dollars per gear reduction, of which, 2/3 of it will be going to bearings anyway.īecause of these "limitations" I only had 2 options, planetary, or strain wave. I cant spend hundreds of dollars on bearings and spacers and screws. The last characteristic is that it needs to be CHEAP. Since I wanted this to be a desktop robotic arm, everything had to be in a small package. I also needed it to be in a small package (bye bye spur reduction). I was hoping for a 30-1 reduction, meaning that when the motor spins 30 times, the output will only spin once. I needed it to be a REALLY good gear reduction. In my case I needed 3 specific characteristics. If you have any other questions regarding the parameters or terms feel free to comment below asking.Now, I'm not going to get into an argument as to which gear reduction is best, obviously each scenario requires different mechanical systems. Therefore m = d / z where m is the module, d is the pitch diameter of the gear and z is the number of teeth.įinally, Pressure Angle, The most common value for pressure angle is 20°, the second most common is 14.5°.The pressure angle defines the angle of the line of action which is a common tangent between the two base circles of a pair of gears, The short of it is this: leave this value at 20 degrees until you have a reason to do otherwise - but know that any pair of gears MUST have the same pressure angle.Īfter entering you parameters now you can click OK and you've made your Helical Gear! Module, the module is the length of pitch diameter per tooth. This prevents overheating and tooth damage. The Helix angle is the degree of twist on the gearīacklash, a clearance between mating gear teeth, is built into speed reducers to let the gears mesh without binding and to provide space for a film of lubricating oil between the teeth. Handedness in helical gears refers to the direction the teeth lean when the gear is placed flat on a table.īy setting a helix angle of 0 degrees, Spur gears can be created and defined in the metric system (as opposed to the sample Spur Gear script which defines gears in the American system) with this add-in. The higher pressure angles provide less contact, so they are smoother and quiet. ![]() At a low pressure angle, the teeth have more contact with each other but that means more noise and backlash (space between meshed teeth, not good). The pressure angle dictates the shape of the teeth. Before we continue you need to know what these different parameters mean. When you select this tool a window will open. ![]() Go to "Solid" then "Create" and at the very bottom will be a tool called "Helical Gear". ![]()
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