Machine Design - Farm Machinery - Agricultural Engineering Previous Year Questions

The RMS sound pressure is increased by 50%. This increases the sound pressure level, in dB, nearly by

A flat belt of negligible mass and thickness drives an output pulley of 0.6 m diameter, constantly rotating at 500 rpm without slip. The arc of contact is 190° for this pulley, while it is 170° for the smaller input pulley. The coefficient of friction between the belt and pulleys is 0.30. The measured slack-side tension is 250 N. Neglecting other losses, the power transmitted by the belt drive, in kW, is nearest to (Take π = 3.14)

A tractor PTO runs at a constant speed of 540 rpm to drive a rotary tiller via flange coupling having a shear pin parallel to the shaft. The shear pin axis is located at 60 mm from the PTO shaft axis. The allowable shear stress of the pin material is 200 MPa. For overload safety, it must fail at 150% of the rated torque to protect the gearbox. The tiller requires 40 kW under normal load at rated PTO speed. Neglecting bending, stress concentration effects, and other losses, the pin diameter, in mm, is nearest to
(Take π = 3.14)

A 2WD tractor has to develop 30 kN gross tractive force at the ground. Rolling radius of the rear-wheels is 0.73 m. Each rear-wheel is driven by a simple planetary final-drive in which sun gear (26 teeth) is input, ring gear (78 teeth) is fixed, and the carrier is bolted to rear-wheel hub. The sun-planet external mesh efficiency is 98.5%, while the planet-ring internal mesh efficiency is 99%. Losses upstream of the final-drive are neglected. The required sun-shaft input torque per rear-wheel (in kN.m) is ______. (Rounded off to two decimal places)

A stationary Ackerman-steer tractor on dry, clean concrete surface carries 12 kN vertical load on each front steered wheel of 0.28 m nominal tyre width (\(b\)). Assume uniform pressure distribution on the circular tyre-print area having diameter \(b\). Effective friction coefficient between tyre and surface is 0.30.
The steering is individually power-assisted by a single-rod hydraulic cylinder, acting through a pitman arm resulting in 60 mm effective moment arm. The hydraulic relief valve is set to 8 MPa, and the cylinder bore is 32 mm (ignore rod area). Neglect other losses. The maximum kingpin offset (in mm), which does not cause to exceed the maximum allowable kingpin torque is ______. (Rounded off to the nearest integer)
(Take \(\pi\) = 3.14)

A tractor PTO shaft, through a spur-gear reduction, drives a small grain auger at 540 rpm. The driving gear on the PTO shaft has 0.18 m pitch circle diameter. The auger requires 3.5 kW, transmitted through this gear. Normal force along the line of action between the meshing teeth is 760 N. Assume involute spur gears, single tooth contact, and neglect friction. The pressure angle (in degrees) is ______. (Rounded off to two decimal places)
(Take \(\pi\) = 3.14)