ME6601 Design of transmission systems question bank

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ANNA UNIVERSITY REGULATION 2008,2013 Subject code/name  : ME6601 Design of  transmission systems Click: DME previous 5 years Anna University Questions        Part A  (2 marks )

	1.What are the types of bevel gear?
	2. In which gear drive self-locking is available.
	3.Give the applications of bevel gear.
	4.What are the advantages and disadvantages of worm gear drive?
	5. What is a herringbone gear and when do we prefer it 6.When to we use bevel gears? 7.What is the virtual number of teeth in a helical gear? 8.Give the applications of worm gear drives. 9.What are the types of failure in worm gear drives? 10.Define the terms (i) Helix angle (ii) Lead angle in worm gear drive. 11.State any three basic rules to be followed while designing a gearbox. 12. Why heat dissipation is necessary in clutches?  13. Differentiate brake and clutch.  14. List the applications of gear box.  15. Why in automobiles, braking action when travelling in reverse is not as effective as when   moving forward? 16. Draw the ray diagram for a six speed gearbox.  17. Define progression ratio and write its expression.  18. What are the types of friction materials used in clutches and give the desirable  properties of good friction materials?  19. In cone clutches semi-cone angle should be greater than 12°.Why?  20. What you meant by self-energizing brake?

Part B   (16  Marks)                   HELICAL GEAR IMPORTANT QUESTIONS

.	A triple threaded worm, having a lead of 75 mm meshes with a gear having 45 teeth and a normal circular pitch of 24 mm. Find the centre distance between the shafts they are 90° apart.
.	A pair of helical gears with 30° helix angle is used to transmit 15 kW at 10,000 rpm of pinion. The velocity ratio is 4:1. Both the gears are made of case hardened steel with a static strength of 10 N/mm2. The gears at 20° stub and the pinion is to have 24 teeth the face width is 14 times the module. Find the module and face width for strength.
.	Design a helical gear to transmit 7.5 kW at 1400 rpm; to the following specifications: Speed reduction is 3, Pressure angle 20°, Helix angle 10°,Design compressive stress 9020 kg/Cm2, Design bending stress 2100kg/Cm2, Take  Modulus of elasticity of materials = 2.05 * 106kg/Cm2  A Pair of helical gears subjected to moderate shock loading is to transmit 37.5 kW at 1750 rpm of the pinion. The speed reduction is 4.25 and the helix angle is 15° FD in the normal plane. Design the gears, assuming a life of 10,000 hours.                                 WORM GEAR IMPORTANT QUESTIONS
	. Design a worm gear drive to 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 40°C. Determine the required cooling area. Design a worm gear drive to transmit 20 HP from a worm at 1440 rpm to the worm wheel the speed of the worm wheel should 40 ± 2 % rpm. Design a worm gear drive to transmit 25 kW at a worm speed of 1400 rpm. Velocity ratio is 25: 1. An   efficiency of at least 80 % is desired. The temperature rise should be restricted to 42°C. Determine the required cooling area. Design a worm gear drive to transmit 15 HP from a worm at 1450 rpm to the worm wheel the speed of the worm wheel should 40 ± 1 % rpm. A worm drive transmits 15 kW at 2000 rpm to a machine carriage at 75 rpm. The worm is triple threaded and has 65 mm pitch diameter. The worm gear has 90 teeth of 6 mm module. The tooth form is to be 20° full depth involute coefficient of friction is 0.1. Calculate (i) Tangential force (ii) Axial thrust (iii) Separating force (iv) Efficiency of the worm drive                      BEVEL  GEAR IMPORTANT QUESTIONS A pair of bevel gears is to be used to transmit 12 kW from a pinion rotating at 360 rpm to a gear mounted on a shaft which intersects the pinion shaft at an angle of 70°.  Assume that the pinion is to have an outside pitch diameter of 200 mm, a pressure angle of 20°, a face width of 40 mm, and the gear shaft is to rotate at 120 rpm. Determine (i) the pitch angle for the gears (ii) the forces on the gears (iii) the torque produced about the shaft axis. 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. . .Design a bevel gear drive to transmit 3.5 kW. Speed ratio =4. Driving shaft speed= 200 rpm. The drive is non-reversible. Pinion of steel and wheel of CI. Assume a life of 25000 hours GEAR BOX IMPORTANT QUESTIONS Design a 18 speed gearbox for a spindle of milling machine. Maximum and minimum speeds are 650 rpm and 35 rpm respectively. The drive is from an electric motor giving 3.75 kW at 1440 rpm. Design a 12 speed gearbox for an all geared headstock 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. Select speeds for a 12 speed gear box for a minimum speed of 16 rpm and maximum speed of 900 rpm. Draw a kinematic arrangement of the gear box showing the number of teeth.  Design a 9 speed gear box for the following data: Minimum speed: 100 rpm, step ratio: 1.25. the input is from a 4 kW, 1400 rpm motor. Draw the speed diagram and indicate the number of teeth on each gear in a kinematic diagram. A nine speed gear box used as a head stock gear box of a turret lathe, is to provide a speed range of 180 rpm to 1800 rpm. Using standard step ratio draw the speed diagram, kinematic layout and find the number of teeth on all gears.        CLUTCH AND BRAKES IMPORTANT QUESTIONS A multiple disc wet clutch is to be designed for a machine tool driven by an electric motor of 12.5 kW running at 1440 rpm. Space restrictions limit the outside disc diameter to 100 mm. Determine the appropriate values for disc inside diameter, total number of discs, and clamping force. A leather faced conical friction clutch has a cone angle of 30°. The intensity of pressure between the contact surface is not to exceed 6*104 N/m2 and the breadth of the conical surface is not to be greater than 1/3 of mean radius if µ=0.20 and the clutch transmits 37 kW at 2000 rpm. Find the dimensions of conical surface. A plate clutch has 3 discs on the driving shaft and 2 discs on the driven shaft,providing 4 pairs of contact surfaces. The outside diameter of the contact surfaces is 240 mm and inside diameter 120 mm. Assuming uniform pressure and  µ=0.3, find the total spring load for pressing the plates together to transmit  25 kW at 1575 rpm. If there are 6 springs each of stiffness 13 kN/m and each of the contact surfaces have worn away by 1.25 mm, find the maximum power that can be transmitted, assuming uniform wear. A friction clutch is used to rotate a machine from a shaft rotating at a uniform speed of 250 rpm. The disc type clutch has both of its sides effective, the coefficient of friction being 0.3. The outer and inner diameters of the friction plate are 200 mm and 120 mm respectively. Assuming uniform wear of the clutch, the intensity of pressure is not to exceed 100 kN/m2. If the moment of inertia of the rotating parts of the machine is 6.5 kg-m2, determine the time to attain the full speed by the machine and the energy lost in slipping of the clutch. What will be the intensity of pressure, if the condition of uniform  pressure of the clutch is considered? Also determine the ratio of power transmitted with uniform wear to that with uniform pressure.  A power of 20 kW is to be transmitted through a cone clutch at 500 rpm. For uniform wear condition, find the main dimensions of clutch and shaft. Also determine the axial force required to engage the clutch. Assume coefficient of friction as 0.25, the maximum normal pressure on the friction surface is not to exceed 0.08 MPa and take the design stress for the shaft material as 40 Mpa. A single plate clutch transmits 25 kW at 900 rpm. The maximum pressure intensity between the plates is 85 kN/m2. The ratio of radii is 1.25. Both the sides of the plate are effective and the coefficient of friction is 0.25. Determine (i) the inner diameter of the plate (ii) axial force to engage the clutch. Assume theory of uniform wear. for all mechanical engineering questions bank download from the link Go to or Copy Past :  annaunivstudymaterials.blogspot.com