Robotics Education & Competition Foundation
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Epicyclic Gear Box Set/Kit For VEX Lifts

2

jamesna888@gmail.com
Entry ID #: 2847
Created: Wed, Dec 7, 2016 9:05 AM


Introduction:

Throughout Team 22283A's years in robotics, we always came across the problem where we run out of spaces for gears to make a high torque four bar lift, six bar lift, scissor lift, etc. Because of this problem, we decided to create a gearbox that increases torque by adding more "chains" of the gearbox in front of the next. Our project is a 3D printed epicyclic gear kit/set which incorporates an epicyclic gear box that can be continuously added on to increase the torque of a system;the more epicyclic gear chains added, the greater the torque. Unlike a single epicyclic gear, our epicyclic gear box uses multiple incorporations of epicyclic gears revolving against a ring gear which generates the movement of a secondary sun gear that turns more epicyclic gears. The entire gear set is able to be connected to both vex plates, pannels, C- Channels, etc. on one end and a vex 393 motor on another end. The epicyclic gears inside are not directly compatable with regular VEX Gears, meaning the interior planetary gears cannot move regular VEX Gears; the gear box itself is very VEX-friendly. Once again, we are pioneering the VEX-friendly planetary/epicyclic gear box, due to the fact that VEX gears can already be made into an epicyclic design(however, VEX doesnt include gear rings), not the planetary gear itself.

 

How it works:

The elaborate system of these gears contain nothing more than a motor attachment end, a shaft inserting end, and inner chains. Below contains brief explanations of how these three parts work together to create a compact, high torque gearbox:

 

- 393 Motor Attachment End

This end of the gearbox which consists of a part where a standard VEX 393 motor can be attached to. On this end of the gearbox, there is a part that elongates out of the gearbox itself. This elongated "shaft" has the same design as a VEX Drive Shaft. The shaft then is able to be inserted into the 393 motor. inside the Motor Attachment end consists of a sun gear and multiple planet gears that revolve when the sun gears move(explained in the Inner Gear Chain/Link description). The only difference between the Motor Attachement End and the Inner Link/Chains is that the Shaft Motor end has the sun gear attached to the elongated motor shaft that is controlled by the motor. More or less, in the Motor Attachment End, the sun gear is moved by the 393 motor. 

- Shaft Insertion End

The shaft Insertion End is the end that has an opening where a standard VEX motor shaft can be inserted into. This end includes a revolving opening end that grasps onto a VEX shaft, which it would then turn. Basically, this is the end where torque is the highest, and it can be used to lift heavier objects. This end also consists of a cap that keeps the planetary gears attached to the opening(shaft insertion square) from falling out of the gearbox. In the middle of the cap, there is an opening that directs a VEX shaft to the shaft Insertion module inside the gearbox. 

- Inner Gear Chain/Link

The Inner Gear Chain/Link is the basis of torque increase and speed reduction for the gearbox system. The more Inner Gear Chain/Link in place, the more the torque increases. The movement created by the Inner Gear Chain/Link is through the movement of the sun gears that are passed on from one Inner Gear Chain/Link to the next. As one sun gear turns the planet gears of another link, the sun gear of the other link would rotate, creating a rotation of the sun gear that is attached to its planet gears. In return, the sun gear of this Link would continuously move the planet gears of another Link, etc. The planet gears move along a ring, which keeps the planet gears in place and also act as the exterior of the gear box itself. The ring acts like the shell of the Inner Link.

 

Design:

The overall design of the gear box looks a lot like an elongated cylinder with a flat end with an opening and a shaft end with an elongated 3D printed drive shaft(attached to a sun gear). On the outside of each ring consists of 4 nubs that come out from the ring and has holes in the center of them. With these nubs, we would be able to change the number of Inner Links that you would like to have, thus changing the torque of the gear box.  On the Shaft Insertion End, there are two seperate nubs that come off from the gear box. These nubs allow a standard VEX Screw and Nut to be passed through, thus securing the gear box onto c channels, plates, etc.

 

Conclusion:

With the help of Autodesk Inventor and Fusion, my team members and I have established a much more concrete idea of the 3D designing process within VEX Robotics. We have found that simply building objects or robots without any preplanning can have some hazardous drawbacks. With inventor, we are able to assemble robots using the CAD Library and easily test/design the best robot for our competitions. Being able to make a complex gearing system specifically for vex parts was a challenge. However, as we learned more about how Inventor/Fusion works,

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