Constant Mesh Transmissoin

Constant Mesh Transmission

A special type of transmission that keeps the gear teeth constantly meshed, hence the name, this is no longer used in modern transmissions, largely succeeded by synchro-mesh transmissions, but is a much easier to understand method of transmissions. 

I created this CAD model to learn about the types of transmission myself, the dog gear design makes it the most printable design, and is cool to see if you like to learn about transmissions. The shifter may not be refined to be the best possible.

Printing: 

All of the parts are oriented properly and no support material is needed. PLA will work, but you can try to use PETG if you want a more durable design. You will likely need to use a brim (auto brim will detect it) for the rods as they are tall, and for the fan / output wheel since its a skinny part.

Assembly:

10 x M3 Bolts

6  x 608RS / 608ZZ radial bearings are used

Step 1

Press fit the bearings into the frame and dog gears.

It is recommended to use a flat tool to press the bearing with a more evenly distributed force.

Step 2

Slide the parts onto the shafts.

On the left (Green):

Make sure to use the 10mm spacers.

On the right (Blue):

Use the 12mm spacers

Make sure that the herringbone gears are pointing in the right direction

Step 3

Slide the 2 halves together, and add the crank and fan onto the corresponding ends.

Step 4

Screw the base plate into the frames. The holes are sized for M3 screws, and the frame should be screwed into.

Step 5

The final step.

Rotate the fork to slide it through the guide.

Snap the fork onto hold both of the dog gears.

Screw in the stabilizing wings onto the fork

Screw the guide onto the frame.