Kaasujousi

Kaasujousi is the Finnish term for a gas spring or compressed‑gas shock absorber, a mechanical device that converts the energy stored in a compressed gas into a controlled linear force. The component typically consists of a sealed chamber filled with a gas—commonly nitrogen—, a piston with a valve, and a lubricating fluid. When the piston moves, the gas expands or compresses, regulating the rate and magnitude of the mechanical reaction.

The core principle of a kaasujousi is based on the ideal gas law. By applying a small volume change to the gas, a large force can be generated, allowing the device to counterbalance loads or dampen motion. The valve controls the fluid flow, thereby tuning the spring's stiffness and damping characteristics. Because the gas is contained under high pressure, the spring can achieve a high force over a short stroke, making it suitable for a broad range of applications.

Common uses for kaasujousit include automotive suspension systems, where they provide a steady load to ride springs; lift‑and‑gate mechanisms in doors, trunks, and tailgates; and heavy‑load equipment such as industrial forklifts, laboratory hoppers, and office furniture. They are also found in consumer products such as reclining chairs, bowling ball pins, and thrust pads on camera lenses.

Variants of the kaasujousi differ in stroke length, force capacity, and construction materials. Stainless‑steel or chrome‑plated housings are typical for corrosive environments, while aluminum variants are preferred for lightweight applications. Modern designs often incorporate modular assemblies that can be replaced separately when the gas pressure falls below a functional threshold.

Because the device operates by compressing gas rather than relying on metal deformation, it offers a longer service life and reduced maintenance compared to conventional coil springs. However, its performance can be affected by temperature fluctuations and gas leakage over time. Regular inspection and periodic re‑pressurization or replacement are recommended to maintain safety and reliability.