Question

What is V-belt. Drive the expression of Ratio in belt tension for V-belt.

Answer 1

 The power from one shaft to another shaft is also transmitted with the help of V-belt drive and rope drive. Fig shows a V-belt with a grooved pulley.

Let R_N = Normal reaction between belt and sides with a grooved pulley.

2α = Angle of groove

 µ = Co-efficient of friction between belt and pulley

R = Total reaction in the plane of groove. 

Resolving the forces vertically, we get

R = R_N sin α + R_N sin α

= 2R_N sin α

RN = (R/2) cosec α .....(i)

Frictional resistance = µR_N + µR_N = 2µR_N = 2µ(R/2)cosec α

= µR cosec α = R ⋅ µcosec α

Since in flat belt frictional resistance is equal to µR, and in case of V-belt µcoseca X R So, 

Ratio of Tension in V-Belt:: T₁/T₂ = e^{µ.θ.cosec α.}