What Is a Damper? How It Differs from a Gas Spring

From the outside the two look almost identical: a tube, a rod, two end fittings. But their jobs are opposites. A gas spring generates force — it lifts the lid and balances the load. A damper generates no force; it absorbs motion — it limits speed and soaks up impact. Inside a gas spring, nitrogen pressure does the work; inside a damper, it is oil, forced through narrow orifices in the piston.

The damper's golden rule: force depends on speed

A damper's resistance is not a fixed value; the faster the piston moves, the greater the resistance becomes. That is why, when selecting a damper, "how many Newtons?" is meaningless on its own — the right question is: how much resistance, at what speed? Damping force is always defined together with a piston speed (for example 300 N @ 0.1 m/s). This is why our configurator asks for speed in ranges: slow (<0.1 m/s), medium (0.1–0.3 m/s), fast (>0.3 m/s).

Two damper families: HK and HA

• HK — Motion control: Keeps the speed of a lid, drawer or mechanism under control; it slows a falling flap and prevents slamming. Structurally it resembles a gas spring, but it is filled with oil. If required, a small gas charge makes the rod extend on its own (F1 option) — so the damper returns to its ready position before every impact.
• HA — Vibration damping: The classic shock absorber family: it converts kinetic energy into heat in continuously vibrating systems such as driver seats, vibrating screens and washing machines. Selection is entirely application-specific; that is why, for HA, the configurator asks not for dimensions but for a description of your application.

Three concepts that come up during selection

• Damping direction: Is resistance required in compression, in extension, or in both directions? For slowing a lid, one direction is usually enough; oscillating systems need both.
• Delayed damping (idle stroke): Some dampers move freely through the first part of the stroke, with damping engaging afterwards. It is position-dependent and requires rod-down mounting — whether that is acceptable in your application is settled in the technical discussion.
• Characteristic: Resistance can rise with speed in a linear, progressive or degressive way. Linear is sufficient for standard needs; for applications that call for a custom curve, the damping force must be defined at two different speeds.

For your damper needs, select the Damper series in the configurator: for HK, the direction–weight–speed steps generate your part code; for HA, simply describe your application — we design the rest together.