Electronic Clutch Gearbox with Locked Synchromesh

Hello everyone

I will tell you about the gearbox that I designed and produced as my internship project.

I designed this project to be able to use two different engineering branches effectively.

This project lasted 5 months. I had a hard time completing the project as I could not find a design or article on synchronized gearboxes. At first I did the project (single stage) without the electronic clutch, but on my first attempt it was difficult to shift gears because the engine was constantly running and there was no clutch mechanism. I started thinking about solving this. The n-stop sensors used in 3D printers gave me an idea and my idea of ​​an electronic clutch emerged. Using a switch, I stopped the engine momentarily and made it easy to shift gears. Then I continued the design and produced it as 5 forward and one reverse gears. 
I also saw that the system I made as an electronic clutch was a system used in my later research. But the detail that I want to emphasize as a result of this project is that I think that vehicles with manual gear can be made electronically clutched with the help of a servo motor.

DESIGN


Instead of using ready-made gears in design, I decided to learn gear design. For this purpose, I designed evolvent profile helical gears using the parametric equations command in Solidworks. You can watch my yotube video about it. You can see pictures of the equations I used. While designing this project, I chose the Porsche 944 Coupe model as a reference for gear ratios. Examining the data of the vehicle, I recalculated the rates here and found the approximate values. When designing the gears, I had to choose a modulus value, and since this value is an important factor in determining gear sizes, I chose a value suitable for the print volume of my 3D printer. Since the modulus value will be different in the group shaft gears, I created an equation to calculate this and for this equation, I calculated the modulus values of the other gears according to the module value of my reference gear and designed accordingly. Since it will be design for production, I designed it by paying attention to the tolerances used in 3D printers. I left a 0.25 mm working clearance. I made my design by leaving a gap between 0.15 and 0.2 mm as a tight fit.

Materials


2 kg PLA Plus filament,
1 kg Tough PLA filament,
6 meters of aluminum pipe with a diameter of 16 mm,
1 key,
1 switch,
1 m cable,
2 fast adhesives,
8 M3 bolts,
12V 2A adapter,
12V 1/18 gearmotor,

Production on 3D printer


I made the production using a 3D printer. I produced gears with a layer height of 0.2 mm using PLA plus material. I produced synchromesh rings with a layer height of 0.12mm using Tough PLA material. I preferred PLA materials because they are harmless to nature and human health and they can be produced easily. Since there is no liquid lubrication system, I used grease oil while fitting the gears. I used 16mm diameter aluminum tubing to reinforce the chassis to carry the gears.

I used reverse engineering methods while designing and producing. I watched the transmission videos and blended it with my technical knowledge and this wonderful project came out. This project will be a great resource for engineering students and engineers interested in gear design and manufacturing. You can find detailed explanations in my Yotube videos.


I used SolidWorks program while designing. Later, I will post the video showing how I made improvements on the chassis using Design Guidance.