Question 3 [15 Marks]
2. and estimate the reliability in use.
The figure shown is a geared countershaft with an overhanging pinion at C. Select an angular
contact ball bearing from Table 11-2 for mounting at O and a straight roller bearing from Table
11-3 for mounting at B. The force on gear A is $F_A = 600 \text{lbf}$, and the shaft is to run at a speed of
420 rev/min. Solution of the statics problem gives force of bearings against the shaft at O as $R_O$
$= 1722j + 2078 \text{N}$, and at B as $R_B = 1406j - 1787 \text{N}$. Specify the bearings required, using an
application factor of 1.4, a desired life of 50 kh, and a combined reliability goal of 0.9.
Figure 1: Dimensions given in inches (please convert to mm)