Suez Canal University Faculty of Engineering Port Said

Production Engng & Mechanical Design Dept

Theory & Machine Design ( Prd 217 ) Total Time 1.5 hours

Machine Design Part

Answer All the questions and assume any missing data

Question No. 1                                                   10 Marks

An Uni-directional 8 pads thrust bearing is required to support a load of 75 Kn. The Start-up load is expected to be about 20 % of the total bearing load . The shaft diameter is to be 0.075 m and the bearing has to operate at max. Speed of 7500 r.p.m. The lubricant available to the bearing is a mineral oil grade 32 ISO VG 32 ) with viscosity index of 95 . The lubricant is supplied in the form of flooded feed with inlet temperature of 50 C o . Bearing misalignment is expected to be exist. It is required to present a full design of that bearing. Draw a sketch to show the general layout and the configuration of the final design of the off –set pad thrust bearing .

N.B.

I- The Vogel’s Eqn. Constants are as follows:

K = 5.95804x10-5   B = 894.233   θ = 106.5863

II- Present your final results of the bearing design as the following pattern :

Pad outside diameter =

Pad inner diameter =

Pad mean diameter =

Pad radial width =

Minimum film thickness =

Length of pad at mean diameter =

Allow. Min. film thickness =

Runner diameter =

Factor of safety of min. film =

Runner thickness =

Inlet temperature to housing =

Pad maximum temperature =

Housing outlet temperature =

Effective film temperature =

The churning power loss =

Film Power Loss =

Total power loss =

Total lubricant feed flow rate =

Maximum surface roughness =

Question No2                                                    5 Marks

A pull of 80 kN is transmitted from a bar X to the bar Y through a pin as shown in the Fig. If the maximum permissible tensile stress in the bars is 100 N/mm2 and the permissible shear stress in the pin is 80 N/mm2, find the diameter of bars and of the pin.