I am studying this in reference to the Gears. What exactly is involute curve and how is it tangent to the base circle??
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Wrap a string around a circle. When you unwind it, the end will trace an involute curve. The base circle is the one it unwinds from. The perpendicular to an involute curve is always tangent to the base circle.
The advantage of the involute curve is that gears with that shape have conjugate action regardless of the distance between them. Conjugate action means that if one gear is rotating at a constant speed, its mate will also rotate at a constant speed, neither speeding up or slowing down. This will is true of involute gears even if the center distance is varied. So machining tolerances are not as critical for constant speed.
For any shape of gear tooth (lets say half a circle) a mate can be designed that will have conjugate action. But if the distance between the gears is not EXACTLY what they were designed for, the action will not be conjugate.
The advantage of the involute curve is that gears with that shape have conjugate action regardless of the distance between them. Conjugate action means that if one gear is rotating at a constant speed, its mate will also rotate at a constant speed, neither speeding up or slowing down. This will is true of involute gears even if the center distance is varied. So machining tolerances are not as critical for constant speed.
For any shape of gear tooth (lets say half a circle) a mate can be designed that will have conjugate action. But if the distance between the gears is not EXACTLY what they were designed for, the action will not be conjugate.