What is the limitation of friction wheels as power transmitt

What is the limitation of friction wheels as power transmitting mechanical components? Does the contact point between the same pair of mating (meshing) teeth remain fixed? What do we mean by conjugate surfaces or profiles? What is the recommended way of obtaining conjugate profiles for mating surfaces?

Solution

1.disadvantages are when the heavy loads are imposed on shafts and bearings, the need for devices to press the rolling bodies against each other is higher, and it has absence of a rigid kinematic coupling.Friction drives are produced for powers ranging from infinitely small values (in instruments) to hundred of kilowatts, ordinarily up to 20 kilowatts

2.No it is not constant.It follows certain curves like involute of cycloidal

3.To obtain the expected velocity ratio of two tooth profiles, the normal line of their profiles must pass through the corresponding pitch point, which is decided by the velocity ratio. The two profiles which satisfy this requirement are called conjugate profile.The most commonly used conjugate tooth curve is the involute curve