Decoupling bellows, in particular for an air inlet system for motors with turbocompressors

The bellows (30) has ripples (36) and a reinforcement textile structure (40). The ripples comprise a large radius of curvature whose center is located inside a cylindrical conduit which is formed by base of the ripples so that length of the bellows is reduced when the bellows is pressurized. The structure has two parts with different rigidities, where the more rigid part is located in a hollow core of the ripples. An independent claim is also included for an air inlet system of a turbo-charged engine of a motor vehicle.