Spring Characteristics and Force Tolerances of Gas Springs1363158
In contrast to almost every other type of springs, strut bracket use a built in pretension force plus a flat spring characteristic. Which means that there is just a small improvement in force between full extension and full compression.
As the piston and piston rod are pressed into the cylinder, volume reduces and pressure increases. This will cause pushing force to improve. In conventional gas-type springs, this increase is usually around 30% at full compression.
The pushing spring movement is slow and controlled. It is just a few the gas flow between the piston sides being allowed to move through channels in the piston during the stroke. Conventional gas springs use 'hydraulic damping', that involves a modest amount of oil slowing down the rate with the stroke immediately before the spring reaches full extension. This provides the movement a braking character by the end position provided that the piston rod is within the downward direction.
Force tolerances when charging with gas and other factors imply that there may be variations inside the force exerted by gas springs with the same nominal value.
The nominal values apply at 20° C, which is temperature at which gas charging is carried out. Note that in the event the ambient temperature rises or falls, the force from the spring rises or falls according to pressure alterations in the cylinder. As a rule of thumb, gas spring force increases by approximately 3.5% per 10° C temperature increase and reduces accordingly if the temperature falls.