Differential

Now that you have already constructed the car, study how the rear wheels are driven.

#775
09 Mar 2018
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The construction should be similar to this one and is called a differential:

The differential consists of two major gearwheels. The first one is called a driving gearwheel and the second one – a crown.

When the blue gearwheel starts spinning, the motion is transferred to the red one and the carrier of the differential starts rotating around the driven shafts. As a result, the inner mechanism of the differential starts rotating as well. This mechanism is called planetary.

The blue gearwheel is attached to the carrier and when it rotates it “goes around” the red gearwheels. Hence, it’s called a satellite gearwheel. Large and heavy-duty machines often have several satellite gearwheels – two, four, etc. In our case, however, there is only one satellite gearwheel.

When the carrier is driven, the blue gearwheel starts rotating as well, then the motion is transferred to the red gearwheels and, as a result, to the wheels of the car. When the car turns and the two shafts move at a different speed, the blue gearwheel spins around its axis and compensates for the difference.

Thus, the differential compensates for the difference in speed and no further intervention on our part is needed.

Courses and lessons with this Tutorial

This Tutorial is used in the following courses and lessons

Instructors Remote Training

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My Blocks

In this section we will learn how to create, edit, import and use My blocks. First we begin with ilustrating a use of My blocks. There is a whole group of robot constructions called steering robots. Today we will build a steering robot and learn more about the way it is driven through a differential. Then you will have to download a My block that implements the Proportional Line Following algorithm for steering robtos. You need to download, import and modify the block to fit your robot setup. Finally, you will have to create a block of your own and learn how to add parameters.

Level C1. "Transportation". Robotics with LEGO

This is the fifth level in the Robotics with LEGO curriculum for students in third or fourth grade.

For the first time robots with steering wheels are built in this level. Those robots use one or two drive motors. The work of the differential and its usage in vehicles is explored. Students learn in-depth the working of the light sensor to create better line-following programs. The first two-wheeled motorcycle-robot is built.

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Lesson 3 - Differential

Introduction

Today we build LEGO vehicle with differential! This will be the robot that would be closest to real automobile with rear wheel drive. We will learn why the differential is the solution to the different speed of the wheels during turns and what happens in case of lack of traction!

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Robotics with LEGO - Level 2.0 - Robots in Factories

The third level of the Robotics with LEGO curriculum for students from fifth to twelfth grades.

Robots in this level use two or three sensors at a time and students create more complex programs for them. The work of the differential and its usage in vehicles with one drive motor is explored. Robots interact with each other and transfer information or material between themselves. Students learn in depth how to create smoother line-following programs. In the end of the workday, robots leave the conveyor belt and relax with a recreational game of volleyball.