Spring Characteristics and Force Tolerances of Gas Springs5395910
As opposed to most other types of springs, gas spring ball stud use a built in pretension force plus a flat spring characteristic. Which means that there is just a small alteration in force between full extension and full compression.
Since the piston and piston rod are pressed to the cylinder, volume reduces and pressure increases. This makes pushing force to increase. In conventional gas-type springs, this increase is generally around 30% at full compression.
The pushing spring movement is slow and controlled. It's dependent on the gas flow involving the piston sides being permitted to move through channels inside the piston through the stroke. Conventional gas springs use 'hydraulic damping', that involves a small amount of oil slowing down the speed from the stroke immediately before the spring reaches full extension. Thus giving the movement a braking character at the end position provided that the piston rod is incorporated in the downward direction.
Force tolerances when charging with gas and other factors mean that there might be variations within the force exerted by gas springs with the exact same nominal value.
The nominal values apply at 20° C, which is temperature at which gas charging is carried out. Observe that if the ambient temperature rises or falls, the force from the spring rises or falls based on pressure changes in the cylinder. Usually of thumb, gas spring force increases by approximately 3.5% per 10° C temperature increase and reduces accordingly once the temperature falls.