All gas springs has a small amount of oil so that it lubricates the main seal and piston rod. This oil also provides the end of stroke damping. If standard gas springs are operated and mounted in a rod-up direction, the fluid oil cannot reach the main seal or gas spring piston rod which leads to overindulgent seal wear and reduced life. It is recommended that standard gas springs be mounted rod down at least 30 degrees off horizontal. If the gas spring application cannot accommodate rod-down mounting, an oil or grease chamber should be specified.

Why gas springs should be used rod-down?

In order to keep the gas spring piston rod and the seal were lubricated, a small amount of oil is used in every gas spring. When used rod-down, the oil is kept in contact with the rod seal which improves the sealing character and ensure the seal will never become dry.

Gas Springs Rod Down
For this reason, one of the basic suggestion when including gas springs in your design is to make sure they are used at an angle of less than 60 degrees from the vertical.

The oil used in the gas spring is also useful to obtain a high damping effect on the last few millimeters of the stroke. If the gas spring was not used rod-down, the piston would not have to go through the oil at the end of the extension and no damping effect would happen.

When this is not possible, and the gas spring has to be used either rod-up or near horizontal, we specify an oil chamber or a fully damped gas spring. While these solutions are not as economical as standard gas springs, they will ensure your gas springs with the same as a standard gas springs used with the rod facing down.

How temperature affects gas spring force: the force produced by a gas spring varies linearly for each degree change from ambient.

Gas Spring & Strut Operating Temperature Range
The following chart gives the operating and survival temperature ranges for gas springs manufactured with standard, low temperature and high temperature seals.