Unformatted text preview: by considering the crankpin in bearing and then checked for bending stress.
dc = Diameter of the crankpin in mm,
lc = Length of the crankpin in mm, and
pb = Safe bearing pressure on the pin in N/mm2 . It may be between
9.8 to 12.6 N/mm2.
We know that FP = dc . lc . pb
From this expression, the values of dc and lc
may be obtained. The length of crankpin is usually
from 0.6 to 1.5 times the diameter of pin.
The crankpin is now checked for bending
stress. If it is assumed that the crankpin acts as a
cantilever and the load on the crankpin is uniformly
distributed, then maximum bending moment will
F × lc
. But in actual practice, the bearing
pressure on the crankpin is not uniformly
distributed and may, therefore, give a greater value
F × lc
of bending moment ranging between P
FP × lc . So, a mean value of bending moment, i.e.
F × l may be assumed.
H1 = Close-up view of an automobile piston 1172 n A Textbook of Machine Design ∴ Maximum bending moment at the crankpin,
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This note was uploaded on 09/30/2012 for the course MECHANICAL 403 taught by Professor A.thirumoorthy during the Spring '11 term at Anna University Chennai - Regional Office, Coimbatore.
- Spring '11