Question

The axes of the two shafts are intersecting and are at 25° to each other. These two shafts are connected by Hook’s joint. At which position of the drives shaft velocity ratio will be maximum?

(a) 90°, 270°

(b) 0°, 180°

(c) 180°, 270°

(d) 90°, 180°

This question was addressed to me in semester exam.

I would like to ask this question from Universal Joints and Differential topic in section Chassis & Transmission System of Automobile Engineering

Answer 1

Correct answer is (b) 0°, 180°

To explain I would say: (ωB / ωA) = (cos α) / (1 – cos^2θ sin^2α) where A = driving shaft and B = driven shaft and α is the angle between shaft  A and shaft B. θ is the angle through which the shaft A rotates. Velocity ratio is maximum when θ = nπ where n = 1, 2, 3, …… i.e. θ = θ° or 180°.