Spring Characteristics and Force Tolerances of Gas Springs7039007
Contrary to most other types of springs, gas spring ball stud use a built in pretension force along with a flat spring characteristic. This means that there is just a small improvement in force between full extension and full compression.
Since the piston and piston rod are pressed in to the cylinder, volume reduces and pressure increases. This makes pushing force to improve. In conventional gas-type springs, this increase is generally around 30% at full compression.
The pushing spring movement is slow and controlled. It really is dependent on the gas flow involving the piston sides being able to go through channels in the piston during the stroke. Conventional gas springs use 'hydraulic damping', which involves a small amount of oil reducing the pace of the stroke immediately before the spring reaches full extension. Thus giving the movement a braking character at the end position provided the piston rod is incorporated in the downward direction.
Force tolerances when charging with gas as well as other factors mean that there might be variations in the force exerted by gas springs with the exact same nominal value.
The nominal values apply at 20° C, which is the temperature at which gas charging is done. Note that if the ambient temperature rises or falls, the force with the spring rises or falls depending on pressure changes in the cylinder. As a rule of thumb, gas spring force increases by approximately 3.5% per 10° C temperature increase and reduces accordingly when the temperature falls.