Page 244 - The Tribology Handbook

--- Piston rings B17

Figure 17.2 Relation between free and closed ring
shape for constant pressure distribution

NEGATIVE OVAL I TY

Figure 17.1 Definition of positive and negative
4(8t - L + 0.0040
ovality fitting stress --

working stress 4(L - 0.0040)
-
-

fitting + working stress 32
-
-
En 2

\ which is independent of free gap L

------------
--.-.__. 3xt FREE GAP
31/4xt FREE GAP
3'/2Xt FREE GAP
__
- - -
4.0
--
-_
------ 33/4xt FREE GAP
3.5 4xt FREE GAP
3.0
2.5
2.0
1.5
1.0 RANGE OF CURRENT PRACTICE
t-
0.5
20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40
QA

Figure 17.3 The effect of the ring radial thickness on the fitting and working stresses
B17.3