F' : output force at 85% efficiency (KGF)--(F' = F×85%)

D: Cylinder diameter (mm)

P: Working pressure (KGF /cm2)

When determining the size of output force in engineering, you can refer to experience Figure 1-1 and Figure 1-2 directly. 

Example: diameter 340mm cylinder, working pressure is 3kgf/cm2, its theoretical output force is what? What is the bud output force?

Connect P and D, find the point on F and F', get:

(2) Length of cylinder stroke:

The stroke of the cylinder depends on the occasion and the stroke ratio of the mechanism (Figure 1-3). It can be seen from Figure 1-3 that the stroke ratio of cylinders varies with different installation forms. The maximum calculated length (L) of the piston rod in the figure can be obtained from empirical data in Table 3-2. In engineering design, the cylinder diameter is selected by the size of the force. According to the actual use of the occasion to check the strength of the piston rod whether longitudinal bending.

For example, there is a cylinder QGBQ125×4000 with a load of 600kgf. It can be found from Table 1-2 that the maximum calculated length of the piston rod L = 2300.

 When the inner diameter of the cylinder is ¦¼125, the diameter of the piston rod is ¦¼35, and the load is 600kgf, the maximum calculated length of the piston rod L = 2300 can be found in Table 1-2.

 In the form of fixed --(a) diagram structure installation, the cylinder allowed stroke is 2L = 2×2300 = 4600.

 Becase the actual stroke of the cylinder is 4000 < 4600.

 So the cylinder does not produce longitudinal bending.