How to solve the cracking of the inner panel at the hinge of the hatchback hatchback door_Industry N

The rapid growth of the economy has led to an increased demand for hatchback mini-cars, which offer the advantages of carrying goods and passengers. Additionally, seven-seat MVPs are becoming more common in ordinary households. Hatchback cars are popular among consumers due to their large lift-back doors and movable rear seats, which allow for additional cargo space when the rear seat is folded. However, the hatchback body, especially the back door frame, has lower torsional stiffness and rigidity compared to sedans. As a result, the back door is prone to twisting, sagging, and damage during driving, such as collisions with walls, taillights, bumpers, or paint peeling. These issues can also cause difficulties in closing the door and decreased noise reduction performance.

With stricter regulations on car quality and the implementation of the three-guarantee policy for automobiles, it is essential for engineers to design the back door sheet metal structure of hatchback cars to ensure durability and customer satisfaction. In this article, we will focus on the problems encountered during the road test of the hatchback rear door hinge and provide analysis, verification, and rectification measures to address the issue of inner panel cracking. The goal is to offer reference and guidance for future development of hatchback rear doors.

The layout of the hinge reinforcement plate of the rear hatchback hatchback is crucial in ensuring the reliability of the connection between the back door and the body. The back-type rear door is suspended on the rear roof beam of the vehicle body through two hinges, with the rear windshield glass bonded to the rear door using glass glue. The hinge reinforcement plate, along with other components like the hinge nut plate, gas spring reinforcement plate, rain scraper motor reinforcement plate, tail light installation plate, limiter reinforcement plate, and door lock reinforcement plate, form the back door sheet metal assembly. It is important to consider the structure, material thickness, and matching relationship of these parts when designing the hinge reinforcement plate.

The hinge reinforcement plate is responsible for providing strength for the hinge installation point and ensuring the reliability of the connection between the rear roof beam and the rear door hinge. During vehicle operation, the hinge experiences various forces, such as torsion, yaw, and vibration, due to the torsion and vibration of the vehicle body. The hinge reinforcement plate plays a crucial role in protecting the interior of the vehicle from external elements, waterproofing, dustproofing, and sound insulation.

To address the issue of inner panel cracking at the hinge, several optimization schemes were proposed and analyzed using CAE analysis. The stress distribution was considered, and the optimal modification scheme was chosen based on a comparison of the sheet metal stress values. The chosen scheme successfully resolved the cracking problem during a reliability road test.

The structural design of the hinge reinforcement plate should consider the extension of the plate to the edge and increase welding points when fitting with the inner panel. Structural adhesive can also be used for bonding if the welding width is not sufficient. The design should avoid deformation of the outer plate edge and consider the convenience of applying glue. When arranging the hinge, it is recommended to place the welding surface between the top of the hinge reinforcement plate and the inner plate outside the wrapping surface of the inner and outer plates. If a spoiler configuration is present, a three-layer welding of the inner plate, hinge reinforcement plate, and outer plate can be used, while a gap should be reserved between the hinge reinforcement plate and the outer plate if there is no spoiler.

In conclusion, optimizing the shape and structure of the hinge reinforcement plate is crucial to reduce stress concentration and improve the reliability of the hinge connection. It is essential for engineers to consider the design of the hinge reinforcement plate in the early stages and ensure a comprehensive approach that takes into account factors like contact area, rib placement, and flange stiffness. These measures will contribute to the overall durability and quality of hatchback rear doors.