Mechanics_Differential and engine

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A differential is a gear train with three shafts that has the property that the rotational speed of one shaft is the average of the speeds of the others, or a fixed multiple of that average.

A differential
 

In automobiles and other wheeled vehicles, the differential allows the outer drive wheel to rotate faster than the inner drive wheel during a turn. This is necessary when the vehicle turns, making the wheel that is traveling around the outside of the turning curve roll farther and faster than the other. The average of the rotational speed of the two driving wheels equals the input rotational speed of the drive shaft. An increase in the speed of one wheel is balanced by a decrease in the speed of the other. 

More on differential 

Here also, I am going to use a toy car differential which had acceptable quality and is structured and acts exactly like a real one:

Motor and differential

 for this set I have completely removed shock absorbers and added two light aluminum rods. I will place the battery on top of it, so considering the weight of the battery there is really no point using those shock absorbers.

Removed shock absorbers

The car originally had a fast, weak, simple brushed DC motor with high power consumption. I removed it and added a 100 rpm 12V DC motor-gearbox, and a heat sink. It is a little bit slow but considerably more powerful and since being able to tackle at least some of obstacles was more vital than speed that was fine. It also has lower consumption but to further limit the current I used a ~10Ω resistor to connect it to its power cord.

New motor-gearbox

Adding this motor-gearbox made it meaningless to use a PWM DC motor controller that I was going to use, since the speed is low and pretty much controllable. I only built a device to control the direction and on/off state that I will explain in detail in another post.

That's it for now.

Arash Ardeshiri

June 28 2021


 





 

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