3-Speed Lego Transmission

This machine is a type of simple transmission made entirely out of Lego's. It is capable of operating at three different gear ratios (1:3, 1:1, 3:1). This model is more of a "proof-of-concept" device and does not include any motors, sensors, or a functional steering mechanism. However, it could be easily modified to accommadate various other components. The way it works is by first transmitting power from the top shaft to the bottom shaft. This is done by means of a special gearing system that ensures that the two shafts are constantly engaged throughout all the machine's various gear configurations. The bottom shaft is able to move back and forth to engage the top shaft with different gears. This horizontal movement is controlled by a rack gear attached to a worm gear reduction gearbox (a motor would be attached to the reduction gearbox in a completed machine). The two sections of the top shaft are not connected, which allows the sections to rotate at different speeds. The power is transmitted from the top shaft to the wheels by a simple systems of gears attached to a differential gearbox. If I get enough requests, I may consider making a functional version with the motors and RCX. However, I worry that the Lego motors would not be able to handle the strain of switching gears at higher speeds.

beerboyone says: Oct 14, 2009. 3:28 AM

i used to have a Lego set with a 4 speed stick shift transmission. Itwas set 8880. it was an amazing set with 4 wheel drive, 4 wheelsteering, full working suspension and the 4 speed transmission.

beerboyone in reply to beerboyoneOct 14, 2009. 3:32 AM

I just found a link to a step by step to build the 8880 car. it has lotsof pictures so you can see the shiting parts and gears. www.eurobricks.com/forum/index.php

twzoom (author) in reply to beerboyoneOct 14, 2009. 6:20 PM

Thanks for the link! That is a really cool Lego set, I can'tbelieve that I've never even heard of it before! I lack all of thespecial pieces required to build the shifting mechanism though. Iwish Lego would come out with a new car that includes all of thoseamazing features, I'd definately buy it :)

matstermind in reply to twzoomJan 6, 2010. 6:46 PM

http://www.peeron.com/cgi-bin/invcgis/scans/8880-1/?ct=1 official instructions

lemonie says: Oct 14, 2009. 1:00 PM

I get the idea but I can't see how you've built it. Strip the box andlay out the shafts that make the gearbox (not the rest of the drivetrain) and add a picture of them?

L

twzoom (author) in reply to lemonieOct 14, 2009. 3:27 PM

I don't have much time right now, but I'd like to make a fullinstructable for this sometime in the near future. I'll see what Ican do.

lemonie in reply to twzoomOct 14, 2009. 3:46 PM

Full Lego Instructables can be a lot of work (with all the pictures).The slideshow is a good format for what you've done, but some differentpictures would be more informative. I usually build them, then take themapart (photographing each reverse step)

L