Addis Ababa Science and Technology University
Department of Mechanical Engineering
Assignment
Brake Design
1) A double external long shoe drum brake is illustrated in Figure. The face width of the
shoes is 50mm and the maximum permissible lining pressure is 1MPa. If the coefficient
of friction is 0.32 determine the limiting actuating force and the torque capacity.
Double external long shoe drum brake
2) A double long internal shoe brake as illustrated in Figure 2 above has a diameter of 200
mm and a shoe face width of 30 mm. The coefficient of friction for the brake lining is 0.4
and the maximum permissible stress is 1.2 MPa. Each brake shoe is actuated by equal
forces. Determine the maximum actuating force on each shoe and determine the torque
capacity for the brake.
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3) The two shoes of the internal brake are identical. The lining is 40 mm wide and the
coefficient of friction is estimated to be 0.35. The brake is hydraulically operated - the
maximum available hydraulic pressure is 8 MPa, and the piston diameters are 18 and 10
mm for left and right shoes respectively.
Find the torque capacity of the brake if the lining mean pressure is limited to 400 kPa.
Calculate the corresponding bearing reactions?
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