The document contains 10 assignments related to mechanical engineering design problems involving belt drives, gear drives, clutches, brakes and other mechanical components. The problems require calculating dimensions, forces, power ratings, efficiencies and other parameters based on given input specifications like transmitted power, speeds, materials and operating conditions. Solutions involve applying engineering formulas and making appropriate design choices and assumptions.

1. ASSIGNMENT -1
1. Design a v-belt drive to be transmitting 45 KW in heavy duty saw mill which works in
two shifts on 8 hrs each. The speed of the motor shaft is 1400 rpm with the
approximate speed reduction of 3 in the machine shaft .design a belt and average
stress induced in the belt.
2. Design a v-belt drive and calculate the actual belt tension and average stress for the
following data. Driven pulley diameter, D=500 mm, driver pulley diameter, d=l50 mm,
center distance c=925 mm, speed N1=1000 rpm, N2 =300 rpm and power, P = 7.5
kW.
3. A v-belt is to transmit 15 KW to a compressor. The motor runs at 1150 rpm and the
compressor is to at 400 rpm .determine design a belt drive.
4. Design a chain drive to actuate a compressor from a 12 kW electric motor at 900
rpm, the compressor begins 250 rpm. Mini mum centre distance should be 500 mm;
the chain tension may be adjusted by shifting the motor on rails. The compressor is
to work 8 hour/day.
5. Design a chain drive to actuate a compressor from 15 kW electric motor running
at1000r.p.m, the compressor speed being 350 rpm. The minimum centre distance is
500 mm. the compressor operates 15 hours per day. The chain tension may be
adjusted by shifting the motor.
6. A truck equipped with a 9.5 KW engine uses a roller chain as the final drive to the
rear axle .The driving sprocket runs at 900 rpm and driven sprocket at 400rpm with
center distance of approximately 600mm.Select the roller chain.
7. A flat belt is required to transmit 35kW from a pulley of 1.5m effective diameter
running at 300 r.p.m. The angle of lap is 165˚and μ=0.3.Determine taking centrifugal
tension into account, width of the belt required. It is given that the belt thickness is
9.5 mm, density of its material is 1.1 Mg/m3 and the related permissible working
stress is 2.5 Mpa
8. Design a wire rope for a vertical mine hoist to lift a load of 30 KN from a depth 600m.
The rope speed is 3 m/s is to be attained in 10 seconds.
9. Select a flat belt to drive a mill at 250 rpm from a 10 KW, 730 rpm motor. Centre
distance is to be around 2m. The mill shaft pulley is of 1 m diameter.
10. Design a V-belt drive to the following specifications: Power to be transmitted: 75
kW, Speed of driving wheel: 1400 rpm, Speed of driven wheel: 400 rpm, diameter of
driving wheel : 300 mm, centre distance: 2500 mm, Service: 16 hours/day.

2. ASSIGNMENT -2
1. Design a straight spur gear drive. Transmitted power 8 kW. Pinion speed 764 rpm.
Speed ratio is 2. The gears are to be made of C45 steel. Life is to be 10,000 hours.
2. Design a spur gear drive required to transmit 45 KW at pinion speed of 800 rpm.
The velocity ratio 3.5:1. the teeth are 20 full depths involutes with 18 teeth on the
pinion. Both the pinion gear are made of steel with a maximum safe static stress of
180N / mm2.
3. Design a straight spur gear drive to transmit 20 kW. The pinion speed is 720 rpm
and the speed ratio is 2.Both the gears are made of the same surface hardened
carbon steel with 55RC and core hardness less than 350 BHN. Ultimate strength is
720 N/mm2 and yield strength is 360 N/ mm2.
4. An electric motor is to be connected to a reciprocating pump through a gear pair.
The gears are overhanging in their shafts. Motor speed = 1440 rpm. Speed
reduction ratio = 5. Motor power = 36.8 kW. The gears are to have 200 pressure
angles. Design a spur gear drive.
5. A compressor running at 300 rpm is driven by a15 KW, 1200 rpm motor through a
14½ 0 full depth spur gears .The centre distance is 375 mm .The motor pinion is to
be of C30 forged steel hardened and tempered, and the driven gear is to be of cast
iron. Assuming medium shock condition, design the gear drive.
6. Design a pair of helical gears to transmit 10kW at 1000 rpm of the pinion.
Reduction ratio of 5 is required. Give the details of the drive in a tabular form.
7. A helical gear drive with the helix angle of 30 degree required to transmit 15 KW at
pinion speed of 10000 rpm. The velocity ratio 4:1. The teeth are 20 degree full
depth involutes with 25 teeth on the pinion. Both the pinion gear is made of
hardened steel with a maximum safe static stress of 100N /mm2. The face width
may be taken as 14 times the module. Find the module and face width.
8. A pair of helical gears subjected to moderate shock loading is to transmit 37.5kW
at 1750 r.p.m. of the pinion. The speed reduction ratio is 4.25 and the helix angle is
150. The service is continuous and the teeth are 200 FD in the normal plane.
Design the gears, assuming a life of 10,000 hours.
9. A helical gear with 300 helix angle has to transmit 35kW at 1500 rpm. With a
speed reduction ratio 2.5. If the pinion has 24 teeth, determine the necessary
module for 200 full depths the teeth. Assume 15Ni 2Cr 1 Mo 15 material for both
pinion and wheel.
10. Design a pair of helical gears to transmit 30kW power at a speed reduction ratio
of 4:1. The input shaft rotates at 2000 rpm. Take helix and pressure angles equal
to 250 and 200 respectively. The number of teeth on the pinion may be taken as
30.

3. ASSIGNMENT -3
1. A 10 kW motor running at 1200 rpm drives a compressor at 780 rpm through a 900
bevel gearing arrangement. The pinion has 30 teeth. The pressure angle of the
teeth is 200. Both the pinion and gear are made of heat treated cast iron grade 35.
Determine the cone distance, average module and face width of the gears.
2. Design a pair of bevel gears for two shafts whose axes are at right angles. The
power transmitted is 25kW. The speed of the pinion is 300 rpm and the gear is 120
rpm.
3. A pair of straight tooth bevel gears has a velocity ratio of 4/3. The pitch diameter of
the pinion is 150 mm. The face width is 50mm. The pinion rotates at 240 rev/min.
The teeth are 5mm module, 14.5O involutes. If 6 kW is transmitted, determine (i) the
tangential force at the Mean radius (ii) the pinion thrust force (iii) the gear thrust
force. Draw the free body diagrams indicating the forces.
4. Design the teeth of a pair of bevel gears to transmit 18.75 kW at 600 rpm of the
pinion. The velocity ratio should be about 3 and the pinion should have about 20
teeth which are full depth 200 involutes. Find the module, face width, diameter of
the gears and pitch core angle for both gears.
5. Design a bevel gear drive to transmit 3.5 kW with the following specifications:
speed ratio = 4; driving shaft Speed = 200 r.p.m.; drive is non-reversible; material
for pinion is steel; material for wheel is cast iron; and life 25000 hours.
6. Design a bevel gear drive to transmit 7.36 kw at 1440 rpm for the following data.
Gear ratio = 3. Material for pinion and gear C45 surface hardened.
7. Design a worm drive for a speed reducer to transmit 15 KW at 1440 rpm of the
worm shaft. The desired wheel speed is 6 rpm. Select suitable worm and wheel
materials
8. Design a worm gear drive a transmit 22.5 kW at a worm speed of 1440 Rpm.
Velocity ratio is 24:1. An efficiency of at least 85% is desired. The
temperature rise should be restricted to 400 C. Determine the required cooling
area.
9. Design a worm gear to transmit 12 KW at 1240 rpm .speed reduction desired
30:1.the worm is made of hardened steel and wheel is phosphor bronze. Checking
heating capacity of gear and determine the efficiency.
10. Design a worm gear drive with a standard centre distance to transmit 7.5 kW from a
warm rotating at 1440 rpm to a warm wheel at 20 rpm.

4. ASSIGNMENT -4
1. The minimum and maximum speed of a six speed gear box is to be 160 and 500
rpm. Construct the kinematic arrangement and the ray diagram of the gear box.
Also find the number of teeth on all gears.
2. Design a 12 speed gear box for an all geared head shock of a lathe. Maximum
and minimum speeds are 600 rpm and 25 rpm respectively. The drive is from an
electric motor giving 2.25 KW at 1440 rpm.
3. Determine a 9 speed gear box to give output speeds between 280 and 1800 rpm.
The input power is 5.5 kW at 1400 rpm. Draw the kinematic layout diagram and
the speed diagram. Determine the number of teeth on all gears.
4. Design the layout of a speed gear box for a lathe. The minimum and maximum
speeds are 100 and 1200 rpm. Power is 5 kW from 1400 rpm. Draw the speed
and kilometer diagram. Also calculate the number of teeth on all gears.
5. Design a 9 speed Gear Box for a machine provides ranging from 200 rpm to 1000
rpm. The input is from a motor 5 KW and 1440 rpm. Assume any alloy steel from
the gear.
6. Construct a ray diagram and kinematic layout for an 18 speed gear box used in a
milling machine. The drive the electric motor of 3.75 KW at 1440 rpm. the
maximum and minimum speed of the spindle are to be around 650 rpm to 35
respectively.
7. In a milling machine 18 speed gear box in the range of 35 RPM AND 650rpm are
required .design a three stage gear box with a standard step ratio. sketch the
layout gear box indicating the number of teeth n each gear .the gear box receives
3.6 KW from the eclectic motor running at 1440 rpm .sketch also the speed
diagram.
8. A gear box is to be designed for the following specifications: Power to be
transmitted = 5.5 KW ,Minimum speed 280rpm and maximum speed 1800 rpm
,input motor speed 1400rpm Draw the kinematic layout diagram and the speed
diagram; Determine the number of teeth on all gears.
9. The spindle of a pillar drill is to run at 12 different speeds in the range of 100 rpm
and 355rpm. Design a three stage gear box with a standard step ratio. The gear
box receives 5kW from an electric motor running at 360rpm. Sketch the
layout of the gear box, indicating the number of teeth on each gear. Also sketch
the speed diagram.
10. A gear box is to be designed for the following specifications: Power to be
transmitted = 12 kW. Number of speeds =18 the minimum speed and motor
speed are 16 rpm and 1400 rpm respectively. Step ratio is 1.25. The 18 speeds
are obtained as 2 x 3 x 3. Sketch the layout of the gear box and the draw the
speed diagram.

5. ASSIGNMENT-5
1. Determine the number of discs required and the maxi.mum intensity of pressure developed
considering a multiple plate clutch with both sides being effective. The clutch transmits
25 kW at 600 rpm. An axial load of 500 N is applied. The inner and outer radii of the clutch discs
are 80 mm and 180 mm respectively. The effective coefficient of friction is 0.3. Assume
uniform wear condition.
2. A square threaded bolt of 25 mm nominal diameter and 5 mm pitch is tightened by screwing
a nut, whose mean diameter of the bearing surface is 35 mm. If the coefficient of friction for
the nut and bolt is 0.12, and for the nut and bearing surface is 0.15, determine the force
required at the end of a 250 mm long spanner, when the load on the bolt is 12 kN.
3. An automotive type internal – expanding double – shoe brake is shown in figure 15b. The face
width of the friction lining is 40 mm and the intensity of normal pressure is limited to 1 N/mm2.
The
coefficient of friction is 0.32. The angle φ1 can be assumed to be zero. Calculate (i) the actuating
force P, and (ii) the torque – absorbing capacity of the brake.
4. A multi – disk clutch consists of five steel plates and four bronze plates. The inner and outer
diameters of friction disks are 75mm and 150mm respectively. The coefficient of friction is 0.1 and
the intensity of pressure is limited t 0.3 N/mm2
. Assuming the uniform wear theory, calculate (i)
the required operating force, and (ii) power transmitting capacity at 750 rpm.
5. A single plate clutch, both side being effective is required to connect a machine shaft to a driver
shaft which runs at 500rpm .The moment of inertia of the rotating parts of the machine is 1Kgm2
.The inner and the outer radii of the friction discs are 50mm&100mm respectively .Assuming
uniform pressure of 0.1N/mm2
and µ =0.25, determine the time taken for the machine to reach full
speed when the clutch is suddenly engaged. Also determine the power transmitted by the clutch,
the energy dissipated during the clutch slip and the energy supplied to the machine during
engagement.
6. A cone clutch is to transmit 7.5kW at 900 rpm. The cone has a face angle of 12° he width of the
face is half of the mean radius and the normal pressure between the contact faces is not
to exceed 0.09 N/mm2
.Assuming uniform wear and the coefficient of friction between
contact faces as 0.2, find the main dimensions of the clutch and the axial force required to
engage the clutch.
7. A multi-disk clutch consists of five steel plates and four bronze plates.the inner and outer
diameters of frication disks are 75 mm and 150 mm respectively. The coefficient of frication is 0.1
and the intensity of pressure is limited to 0.2 N/mm2
.assumeing the uniform wear theory
calculation (i) the required operating force and (ii) power transmitting capacity at 750 rpm.
8. A single plate clutch, both sides being effective, is required to connect a machine shaft to a driver
shaft which runs at 500 rpm. The moment of inertia of the rotating parts of the machine is l kgm2.
The inner and outer radii of the friction discs are 50 mm and 100 mm respectively. Assuming
uniform pressure of 0.1 N/mm2 and coefficient of friction of 0.25, determine the time taken for the
machine to reach full speed when the clutch is suddenly engaged. Also determine the power
transmitted by the clutch, the energy dissipated during clutch slip and the energy supplied to the
machine during engagement
9. A single plate clutch is used for an engine that develops a maximum torque of 120 N-m. Assume a
factor of safety of 1.5 to account for slippage at full engine torque. The permissible intensity of
pressure is 350 KPA and the coefficient of friction is 0.35. Calculate the inner and outer diameters
of the friction lining and the axial force to be exerted by the springs to engage the clutch.
10. A multi – disc clutch has three discs on the driving shaft and two on the driven shaft is to be
designed for a machine tool, driven by an electric motor of 22 kw running at 1440 rpm. The inside
diameter of the contact surface is 130mm. The maximum pressure between the surfaces is limited
10 N/mm2. Design the clutch. Take μ = 0.3 ; n1 = 3; n2 = 2.