Lego Technic Powerful 2 Speed Auto Gearbox
Here I present my design for a compact and powerful Lego Technic 2 speed automatic gearbox.
The gearbox uses the Lego Technic Powered Up functions to detect speed and deduce torque from that to make gear switching decisions. The gearbox switches between a high gear of 1 to 4, to a low gear of 1 to 12 (giving 3 times the torque at the output).
The gearbox is demonstrated using a proof of concept pushing vehicle to push two Lego Technic models across a table top. In the high gear the vehicle can only push one model, however when switching down a gear it can push both models.
The gearbox is so strong it can twist an axle more than three revolutions.
More to explore
Lego Technic PU 2 Speed Automatic Gearbox
This video presents a lego technic two speed automatic gearbox using two motors and the Powered Up (PU) lego technic control system. Each motor uses a pivoting gear to either connect to it's gear to the left when rotating in the forward direction or to the gear to the right when reversing. Th...read more
New Flat 12/20 Gear Friction
The Lego Technic set 42140 App-Controlled Transformation Vehicle introduces two new gears - a flat version of the 12 tooth bevel gear and a flat version of the 20 tooth bevel gear. These gears are designed to have less friction.
In this video I measure the difference in gearing efficiency...read more
Measuring Gearbox Efficiency
This video describes a method for measuring the efficiency of a gearbox using the Lego Technic Powered Up hub. Gearbox efficiency is defined as the ratio of the output power to the input power and here I show how to measure each of these values to allow you to calculate the overall efficiency.read more
Lego Technic Gearbox Theory Applied - how to apply theory to help design 2 speed automatic gearboxes
This video applies lego technic gearbox, torque, and gearing ratio theory to design a prototype lego 2 speed automatic gearbox. First I describe the main components of an automatic gearbox, namely a gearing ratio selector and a torque detector. The ideal gear switch over torque point is described...read more
Lego 2 speed automatic car. Part 1
This video explores the use of the lego technic "smoothly switching 2 speed automatic gearbox" inside of a test car to see how well it works to climb up a ramp.
The gearing ratio of the 2nd gear of the 2 speed automatic gearbox can be set using a manual 4 speed gearbox to choose...read more
Lego Technic smoothly switching 2 speed automatic gearbox evolution with instructions
This video presents my latest compact and smoothly switching 2 speed automatic gearbox made out of Lego Technic. It is both smoothly switching and compact.
The MOC gearbox automatically switches down in gearing ratio when the load on the output is sufficiently high by using a new te...read more
How to measure a Lego Technic Crane's Efficiency. The results surprised me!
Here I demonstrate how to measure the efficiency of a Lego Technic MOC crane using basic physics. Efficiency is the ratio of the useful energy output (the potential energy put added to the weight) the to the input energy (power source power). The efficiency curve is interesting and does not look ...read more
Lego Technic Gearing Ratio Calculator Tool
Here I present my new Lego Technic Gearing Ratio Calculator tool. This tool allows you to upload your Lego Technic .ldr (Lego Draw) file and it will simulate the gearing system and visualize it as well as showing the gearing ratios relative to the input component.
The tool can be accessed...read more
Lego Technic 2 Speed Automatic Gearbox with Booster Motor
A lego technic 2 speed automatic gearbox is presented. The point of difference of this automatic 2 speed gearbox is a secondary booster motor is activated once the torque detector senses a large enough torque on the output of the automatic gearbox.
The second motor is turned on by a pole ...read more
Lego Technic 2 Speed Auto Car Ramp Challenge - Part 2
A lego technic 2 speed automatic gearbox is put to the test by incorporating it into a lego 2 speed automatic car. This lego 2 speed automatic gearbox implements a number of design principles aimed at improving the gearbox performance - namely of placing the torque detector on a separate pa...read more