Differentials

[willharris]

How does a differential work?<br>

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Why doesn't one wheel go backwards and one forwards?

 

[MikeVV]

The differential transmission solves two problems - it takes a single input torque and splits it into two output torques (shafts) and also &quot;divides&quot; the torque so that only one shaft gets the full &quot;force&quot; - the other &quot;follows along.&quot; The two sets of gears inside the transmission &quot;lock-up&quot; during normal use. If one wheel is allowed to slip, the gears inside are spinning however. This allows one wheel to rotate at a slightly slower speed than the other (which is needed during a turn). <br>
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If you could watch the gears during a turn (imagine a clear transmission housing) they would be rotating slightly as they continue to move &quot;forward&quot; in a turn. In other words, two things are happening simultainiously, the main pinion gear rotates the ring gear which provides torque to both bevel gears. At the same time, the bevel gears are allowed to rotate which makes one output shaft spin slightly slower than the other. They still rotate &quot;forward&quot; but one can &quot;slip&quot; with respect to the other. When rolling along straight, the bevel gears do not rotate, only when rolling along a curve.<br>
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