P
Helical spur gear
diameter D
possible
Fillet, radius r
Solid shaft,
diameters d and D
dections of diameters D
axial (P.), radial (P.),
are given
strength S
tangential (P) components
haft diameters D = 39 mm and d = 23 mm,
shoulder fillet radius r = 3.5 mm,
distance L = 60 mm,
young's
diameter D, = 250 mm,
P, = 450 N,
P, = 850 N,
and the tangential P, = 2100 N.
The material data are
Young's Modulus, E = 126 GPa,
Shear Modulus, G = 51 GPa,
Poisson's ratio, v = 0.23,
Yield strength oy = 900 MPa,
and ultimate strength ou = 1100 MPa
at the shaft shoulder has a radius r.
strength S,. The gear is of diameter D, (ignore the gear thickness).
shown on the figure (not to scale).
a) Calculate the factor of safety for static yielding based on the maximum energy (Von Mises) criterion.
The answer is acceptable within a tolerance of \textpm{}1, but within a 5\% tolerance will score 3 marks
F.O.S. (5 mark)
F.O.S. (5 mark)
to the bending of the shaft
105 cycles at 50\% reliability
required.
slight
obtained from Roark's formulae
notch sensitivity factor q must be calculated
tivity factor)
Peterson's formula, with a = 0.25 mm (see tutorial notes).
