Anjuman-i-Islam’s

M.H.SABOO SIDDIK COLLEGE OF ENGINEERINGByculla, Mumbai-400 008.

Department Of Automobile Engineering

Automotive Design

Prof.Shaikh Ibrahim.I.

Assignment No 04 Date of sub. : 24/10/2017

www.ibrahimshaikh.com

Q.01) Attempt the following questions

a) Prepare a list of brake lining and clutch lining materials used in automotive. Specify their characteristics.

b) Explain the utility of the centre bolt, U-clamp, and rebound clip in a leaf spring.

c) What are the different materials used in advanced automotive body structures

d) What are the applications of multi-leaf spring?

e) Name the different types of clutches. Give at least one practical application of each.

Q.02) Design a propeller shaft for an automotive, whose engine develops 40 kW at 1800 rpm. The lower gear ratio being 3.50 .Assume a suitable diameter ratio and shear stress of 56 MPa for the material of the shaft.

Q.03) A semi elliptic multi leaf spring is used for the suspension of the rear axle of a vehicle. Itconsists of two extra full length leaves and ten graduated length leaves including the master leaf. Thecenter to center distance between the spring eyes is 1.2 m .The allowable stress for spring material isσyt = 1500 N/ mm2 and E = 2.1 x 105 N/ mm2.The factor of safety can be assumed as 2.5.Design thecross section of the leaves for a maximum force of 40 kN.

Q.04) A sliding mesh gearbox contains 4 pairs of gears for providing 4 forward speed 10 and a reversespeed. Speed ratio of clutch shaft gear and lay shaft gear is 2.5 Calculate the number of teeth in all thegears with the assumptions that minimum number of teeth required for any gear to avoid interferenceis 18. Finally, calculate actual gear ratios. The gearbox should have the following speed ratiosapproximately:First gear = 4.5Second gear = 3.38Third gear = 2.25Fourth gear = 1Reverse speed gear = 5.0

Q.05) An automotive single plate clutch consists of two pairs of friction surfaces.Eight identical helicalcompression springs, arranged in parallel, provide the required axial thrust on the friction surface. Thetotal spring force exerted by all springs is 2400 N and the corresponding deflection of each spring isapproximately 15 mm. The spring index can be taken as 8. The springs are made of patented and cold-drawn steel wire with ultimate tensile strength of 1390 N/mm2 and modulus of rigidity of 81 370 N/mm2. The permissible shear stress for the spring wire can be taken as 30% of the ultimate tensilestrength. Design the springs completely

Date of comm.: 19/10/2017

Q.06) An automotive engine has an output of 80 kW at 3000 rpm. The mean diameter of the clutch is 200 mm with a permissible pressure of 0.2 N/mm2 .Friction lining is of asbestos with μ = 0.22. What should be the inner diameter of the disc? Take both the sides of the plate with friction lining as effective. There are 8 springs and axial deflection in spring is limited to 10 mm. Design the spring. Assume G = 80 kN/mm2 and C = 6.

Q.07) An automotive single plate clutch consists of two pairs of contacting surfaces. The outer diameter of the friction disk is 270 mm. The coefficient of friction is 0.3 and the maximum intensity of pressure is 0.3 N/mm2. The clutch is transmitting a torque of 531 N-m. Assuming uniform wear theory, calculate: (i) the inner diameter of the friction disk; and (ii) spring force required to keep the clutch engaged. Q.08) A multi-disk clutch consists of two steel disks with one bronze disk. The inner and outer diameters of the contacting surfaces are 200 and 250 mm respectively. The coefficient of friction is 0.1 and the maximum pressure between the contacting surfaces is limited to 0.4 N/mm2. Assuming uniform wear theory, calculate the required force to engage the clutch and the power transmitting capacity at 720 rpm.

Q.09) A centrifugal clutch, transmitting 18.5 kW at 720 rpm, consists of four shoes. The clutch is to be engaged at 75% of the running speed. The inner radius of the drum is 165 mm, while the radius of the centre of gravity of each shoe, during engaged position, is 140 mm. The coefficient of friction is 0.25. Calculate the mass of each shoe.