Table 8.1

Allowable mean pressure [p], in MPa

n1, rpm	Chain pitch, mm
12.7	15.875	19.05	25.4	31.75	38.1	44.45	50.8
							-	-
						-	-	-
					-	-	-	-

8.6. Determine the chain pitch

,

where T₁ is in N×m.

Round off the pitch to the nearest standard value according to the table 8.1. In our case assume t = 31.75 mm.

8.7. Specify the allowable mean pressure according to table 8.1 by interpolation [p]. On multiplying it by

K_p = 1 + 0.01·(z₁-17) = 1 + 0.01·(26-17)=1.09 we get finite magnitude of [p] = 29·1.09=31.61MPa

8.8. Determine the effective mean pressure.

For that we

- find chain speed

;

- find turning (tangential) force

;

- look up the projected hinge area S_h using table 8.2. In our case S_h=262 mm²

Then the effective mean pressure

.

If this inequality is not right it is necessary to increase the pitch t.

;

inequality is right.

8.9. Determine the number of links in the chain

,

where is the chain length in pitches; ; a» (30…50)·t; z_S = z₁ + z₂; . Round off obtained magnitude to even integer numeral.

In our case: a_t = 45; z_S = 26 + 65 = 91; ;

8.10. Specify the centre distance

The slack side of the chain should have a slight sag f» 0.01·a, for which purpose the design centre distance is reduced by 0.2 to 0.4 %.

Assume that a = 1418.76 mm.

8.11. Determine the pitch diameters

- of the driving sprocket ;

- of the driven sprocket .

8.12. Determine the addendum diameters

where d₁ is the roller diameter (table 8.2).

8.13. Determine the dedendum diameter

,

.