Ultimate gearbox variable gearing

thingiverse

This gearbox is quite customizable, but will require some effort from you. It is designed to have a transfer of motion with 5 gears meaning 4 different ratios. You select which ratios you want and then create the gears based on your needs. I have included the following gear ratios, 1:1, 1:2, 1:2.5, 1:3, & 1:4 The gears are based on a common axle to axle distance of 25mm. That means that the pairs of gears are matched so they can stack. Just because a gear has 8 teeth doesn't mean it is interchangeable with another set. Sets consist of a Large, Small, and Driver gear. The Small and Driver only differ in the hole size. Driver has a 2mm hole which should fit a lot of DC motors. All the gears are build with .1mm tolerance and should not whine loudly when running (working to improve this). Something I had when building prior gear boxes. You may need to play with the expansion values. In cura I personally have those set to -.1mm. An example: I wanted a 1:60 gearing, I break that number into its primary factors. (Back to basic math!) That would be 2, 2, 3, 5. Notice that I don't have a 5 so you split that into 2, and 2.5. So the final is 2,2,2,2.5,3. That is five but we only have 4 transfers so it becomes 2, 2.5, 3, 4. This produces a 1:60 gear box. (multiply those 4 values together to get the end gearing) It doesn't cover every ratio but it should get you close to what you need. Basically from a 1:2 to 1:256 gear ratios are possible. The five gears are composed of the driver gear which connects directly to the motor and then four stacks of two gears, a Large on bottom and a Small on top. With Cura you can place two models on each other and print them together. That is how I hope this works for you. You may need to turn off Preferences->General->Automatically drop models to the build plate to allow you to stack the gears. So back to our 1:60 example, We need a 1:2, 1:2.5, 1:3, 1:4 Let's starting with our lowest, 2. We select the 1:2 set and select the driver gear from that set. The Driver 1:2 will fit on a motor. The Large 1:2 is the base for the first gear set, Next the Small 1:2.5 is placed on top. The Second gear is a Large 1:2.5 and a Small 1:3. Next the Large1:3 and the Small1:4. Finally we have the Large1:4 and the Shaft which is what you can connect to and will have the reduced ratio. The Shaft is printed on top of the Large1:4 the same as you would a small gear. NOTE: This set is meant to use bearings! specifically the 683zz (3x6x3) Or MR62zz (2x6x2,5). These ARE NOT interchangable SO there are actually two entire sets of gears. You should be able to purchase these bearings off of Amazon. I found a set of 20 for $8 on prime. Another set of 50 for 13. The files are named so that they hopefully will be easy to select and use. {Type}{Ratio-1}{_bearingDiameter}. So a large spoked 4:1 with a 7mm axle is named SpokedLarge1-4_7. This is still a work in progress.