Buffer, suspension system and vehicle

The invention provides a buffer, a suspension system and a vehicle, relates to the technical field of vibration reduction, and aims to solve the technical problem of poor reliability of a bidirectional buffer. The buffer comprises a cylinder body, a piston and a piston rod. The cylinder body is provided with a closed end and an open end which are opposite. The piston is slidably arranged in the cavity of the cylinder body, and the part, located between the piston and the closed end, of the cavity is used for storing gas; the buffer further comprises a reset element arranged on the piston rod in a sleeving mode and a sleeve. The reset element and the sleeve are distributed in the direction away from the piston. Wherein the sleeve is slidably arranged on the piston rod; the buffer further comprises a first limiting structure close to the opening end, and the first limiting structure is provided with a first annular structure protruding out of the inner wall of the cavity. The outer diameter of the sleeve is lar