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Unformatted text preview: e radial thickness (t1) of the ring may be obtained by considering the radial pressure between
the cylinder wall and the ring. From bending stress consideration in the ring, the radial thickness is
t1 = D σ
where D = Cylinder bore in mm,
pw = Pressure of gas on the cylinder wall in N/mm2. Its value is limited
from 0.025 N/mm2 to 0.042 N/mm2, and
σt = Allowable bending (tensile) stress in MPa. Its value may be taken
from 85 MPa to 110 MPa for cast iron rings.
The axial thickness (t2 ) of the rings may be taken as 0.7 t1 to t1.
The minimum axial thickness (t2 ) may also be obtained from the following empirical relation:
t2 = 10 n
nR = Number of rings.
The width of the top land (i.e. the distance from the top of the piston to the first ring groove) is
made larger than other ring lands to protect the top ring from high temperature conditions existing at
the top of the piston,
∴ Width of top land,
b1 = tH to 1.2 tH
The width of other ring lands (i.e. the distance between the ring grooves...
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- Spring '11