runkorakenteen

Runkorakenne, or frame construction, is a structural approach in which a rigid frame carries the primary loads of a system. In automotive engineering, the frame serves as the main load path for the engine, drivetrain, suspension, and body. The body is mounted to the frame rather than forming the primary structural element, allowing the frame to absorb and channel forces during operation and impact.

Frames are typically fabricated from steel, and sometimes aluminum or composite materials. Common configurations include ladder frames, boxed frames, and other beam-based geometries with crossmembers that provide rigidity and mounting points for axles, suspension, and body panels. The frame often functions as a protective skeleton for components exposed to rough terrain or heavy use, and it can be repaired or replaced more readily in some cases than a fully integrated body structure.

In contrast, unibody (or unitized body) construction combines the load-bearing function of the chassis with the body into a single integral structure. Unibody designs generally offer lighter weight and improved crash energy management and manufacturing efficiency, but may have lower maximum towing or off-road durability compared with traditional frames in certain applications.

Runkorakenteita on tyypillisesti käytetty raskaissa ajoneuvoissa, kuten kuorma-autoissa, maastoautoissa ja joissakin hyötyajoneuvoissa, sekä vanhemmissa henkilöautoissa. Nykyään monet kevytautot käyttävät pääosin unibody-rakenteita, mutta frame-based ratkaisut säilyvät suosittuina vaativissa käyttötarkoituksissa, missä korroosion hallinta, korjattavuus ja vetokyky ovat keskeisiä.