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5. Integrated GearBox Module

Design Report – Integrated Gearbox Module                 An important part of any VEX robot is creating gear systems to transfer motor power to other devices, or to change the amount of torque and speed your motor can produce. The problem is that VEX only sells large external gears. This creates a number of problems when creating a gearing system for a robot. The large external gears mean gear systems are large and bulky, and they take up a lot of space on the robot, are complex to build and inefficient. They also tend to have high amounts of friction, and if a team decides to change the gear ratio later, this often means a large re-designing of the robot. We aimed to fix this problem by designing a more efficient way to create gear systems in VEX.                 For inspiration we looked to how gearing systems are done in other robotics systems. With larger electric motors gearing is usually done by way of a self contained gearbox. There a number of advantages to this design. Standard gearboxes are easy to design for. They are compact, efficient, and easy to lubricate. However these still have problems; the gear ratio is still difficult to change, and the boxes only come in limited gear ratios. We decided to make gearboxes that came in a variety of ratios, all in one standard external box. That way, if a team wants to change the gear ratio of a device they can simply switch out the gears inside the gear box, and they don’t need to re-design any other part of the robot. The gear boxes come in 2:1, 3:1 and 5:1 ratios to allow teams a wide variety of options. The gear boxes are also reversible, meaning a team can just flip the gear box over, and switch which side the input and output shafts go into. Doing this switches the ratio from increasing output torque, to now increasing output speed. This opens up the possibilities of 1:2, 1:3, and 1:5 gear ratios. While this is certainly better than the current system, we were still not satisfied with the results; teams often need gear ratios other than the 6 listed here. We considered it impractical to create more internal gear sets, as it would be difficult to produce a large number of different gear sets, and then teams would have to purchase a new gear set every time they wanted a new ratio. We came up with a better alternative, by making the gear boxes stackable, and combinable. By doing this we have opened up the possibility for virtually any gear ratio. The gear boxes we have created are designed to be stacked and combined. This opens up many ratios, even ones that cannot currently be created with the VEX system, such as a 1.66:1 ratio, by combining a 5:1 and a 1:3 gear box. To Design this system we used Autodesk Inventor Professional. This software includes a built in gear making tool that we used to create all of the gears. Autodesk also include built in software to expand and animate assemblies and we used this ability to create a demonstration of how the gearboxes might be assembled.                   This system opens up a lot of possibilities for VEX teams. These new gear boxes are small, less than the size of a VEX 393 motor. These new gear boxes allow teams to easily design a system where they can quickly change gear ratios without buying a new system. The self contained boxes are easy to lubricate and maintain, and allow teams to create almost any gear ratio they could desire by combining and stacking boxes. In virtually every way these Integrated Gearbox modules are a vast improvement over the current gearing system.          here is a link to our google drive where pictures and video can be found https://drive.google.com/folderview?id=0B1LLlSCW4Hm5Mld4TUdsT2Nmc2s&usp=sharing and here is a link to the same video on youtube https://www.youtube.com/watch?v=2mbdrcitumg