The backrest skeleton is a key structural part of the seat assembly. Its main functions are to maintain the correct sitting posture, provide support for the upper body when turning, and protect the upper body when collision occurs. The performance of the backrest skeleton directly affects the strength, stiffness, stability, and even the quality and grade of the seat assembly.
The rear seat backrest skeleton can be divided into three categories according to its structure and manufacturing process: tube frame type backrest skeleton (no metal backrest), tube frame type backrest skeleton (with metal backrest), sheet metal type backrest skeleton.
1. Tube-frame type backrest framework (no metal backrest)
The tubular frame type backrest frame structure is simple, easy to manufacture, the lowest cost; However, the strength and stiffness are also relatively low, and it is difficult to achieve complex functions. Widely used in low-cost seats.
The main material of the tube frame type backrest skeleton is: welded pipe and punch steel plate with simple shape. The welded pipe material is generally Q235, Q345, QSTE420, QSTE500, etc. The outer diameter of the welded pipe is mainly Φ25mm, Φ30mm, Φ32mm, and the wall thickness is generally 1.2mm, 1.5mm, 2.0mm. Stamped steel plate generally adopts QSTE420, QSTE500, SAPH440 and other medium-strength plates, the thickness is generally 2.0, 2.5, 3.0mm. After the welded pipe is bent and formed by two-dimensional or three-dimensional pipe bender, it is welded with the stamping steel plate through carbon dioxide gas shielded welding process to form the backrest skeleton component.
2. Tube-frame type backrest framework (with metal backrest)
The metal backrest is added on the basis of the tubular frame backrest (no metal backrest). The material of the metal backrest is generally DC01, DC03 and QSTE340, and the thickness of the material is 0.5mm and 0.6mm. The metal backrest and the frame are connected by spot welding, which is generally used for the seat of mid-class car models.
3. Full sheet metal backrest skeleton
This kind of skeleton shape is more complex, high strength, light weight, generally used for more complex functions, high cost seats. The stamping steel plate is generally made of medium strength steel plate such as B410LA, SAPH440, QSTE460 and deep drawn sheet plate such as DC04. The wall thickness is generally 1.0mm, 1.2mm and 2.0mm. After the stamping steel plate is formed, the backrest skeleton component is welded by spot welding or carbon dioxide gas shielded welding process.