Standard gas springs

A standard gas spring is a closed cylinder tube filled with high pressure gas and a rod that can be inserted into it (Figure 2). The end of the rod in the tube is fitted with a slotted piston, so the pressure on both sides of the piston is the same. Since the pressure surface area on the rod side of the piston is smaller than the cross section of the rod, the gas pressure forces the rod outwards.

Figure 2 – Main structural parts of a standard gas spring

The theoretical spring force can be calculated using the formula F = Ar p where:
Ar is the cross section of the rod,
p is the pressure of the charge gas in the cylinder tube

Figure 3 – Real spring characteristics of a standard gas spring and spring coefficient (x)

F1 = Displacement force in the extended position of the rod
F2 = Displacement force with the rod in the retracted position
F3 = Insertion force with the rod in the extended position
F4 = Insertion force in the inserted position of the rod
Fs = Displacement force

The resistance to friction (friction force) increases the theoretical spring force when the rod is pushed in and decreases it when it moves outwards.

In a closed space, gas pressure varies with temperature, 0.3% per oC.

Marking:

MS08-1-1F6D-200-100-300

MS – standard gas spring
08 – rod diameter (8mm)
1 – damping
1F – end fitting tube side
6D – end fitting rod side
200 – extension force
100 – stroke
300 – structural length

Range of sizes and specifications of standard gas springs:

Figure 4 – Standard gas spring size range

* in 5mm increments
** measured at +20 Co
*** to avoid rod deflection
Possible damping: 1, 2, 3, 4.