If the drive efficiency is 80%, the torque required on

Home » Theory of Machines » Theory of Machines Miscellaneous » Question

Direction: A compacting machine shown in the figure below is used to create a desired thrust force by using a rack and pinion arrangement. The input gear is mounted on the motor shaft. The gears have involute teeth of 2 mm module.

If the drive efficiency is 80%, the torque required on the input shaft to create 1000 N output thrust is

1. 20 Nm
2. 25 Nm
3. 32 Nm
4. 50 Nm

Correct Option: B

Given: Module m = 2,

	D	= 2
	T

∴ D = 80 × 2 = 160 mm
2F = 1000, or F = 500 N

Let T₁ be the torque applied by motor.
T₂ be the torque applied by gear.
∴ Power transmission = 80%

T₁ ω₁ =	2T₂ × ω₂
	0.8

or T₁ =	2 × F × (D / 2)	×	ω₂
	0.8		ω₁

= 2 × 500 ×	0.16	×	1	×	1	= 25 N-m
	2		0.8		4