Lightweight structure of foam and fiber reinforced composite combination for automotive rocker
Patent Information
- Application Number
- CN202522391737.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-11
- Publication Date
- 2026-09-15
- Estimated Expiration
- 2035-11-11
AI Technical Summary
[0012] The beneficial effects of this invention are as follows: By combining a high-strength energy-absorbing foam core with a fiber-reinforced composite material shell, this invention significantly reduces the overall weight of the car door sill structure, overcoming the drawbacks of traditional extruded aluminum materials being too heavy, and effectively meeting the lightweight requirements of modern automobiles. During a collision, the foam core and the composite material layer deform synergistically through interfacial adhesion, jointly absorbing and dispersing impact energy, greatly improving the structure's energy absorption efficiency, thereby effectively reducing intrusion into the passenger compartment and enhancing side-impact safety.
Smart Images
Figure CN224752597U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of vehicle parts technology, specifically relating to a lightweight structure combining foam and fiber-reinforced composite materials for automobile door sills. Background Technology
[0002] With the continuous improvement of automotive safety standards, especially the increasing requirements for side-impact safety performance, the vehicle door sill, as a crucial energy-absorbing and force-transmitting component in side collisions, faces significant challenges in its structural design and material selection. Currently, most models on the market use extruded aluminum alloy door sill structures, which are widely used in electric vehicles and other fields due to their good crashworthiness and forming flexibility. However, traditional extruded aluminum door sills, due to their high material density, result in a relatively large overall weight, making it difficult to meet the trend of lightweight automotive development. This is especially true in new energy vehicles, where the placement of the battery pack further increases the overall vehicle weight, placing even higher demands on the lightweight design of the door sill structure.
[0003] In addition, although there have been attempts to use fiber-reinforced composite materials to prepare sill structures in existing technologies, such as by using regular polygonal cross-section design or wrapping reinforcement layers on the outer surface to improve impact resistance, there are still problems such as insufficient structural stiffness, complex connection, and limited energy absorption efficiency. They are prone to deformation or damage during collisions, making it difficult to effectively ensure the survival space of the occupant compartment and the safety of the battery pack.
[0004] Therefore, it is necessary to provide a new type of door sill structure that can achieve significant weight reduction while ensuring or even improving collision safety performance, in order to meet the comprehensive needs of modern automobiles, especially new energy vehicles, for safety, weight reduction and integration. Utility Model Content
[0005] The purpose of this invention is to provide a lightweight structure combining foam and fiber-reinforced composite materials for automobile door sills, in order to solve the problems existing in the prior art.
[0006] To achieve the above objectives, this utility model provides the following technical solution: a lightweight structure combining foam and fiber-reinforced composite materials for automobile door sills, comprising: A fiber-reinforced composite material layer constitutes the outer shell of the structure; An energy-absorbing foam core is filled and wrapped in the internal cavity of the fiber-reinforced composite material layer, and the outer surface of the energy-absorbing foam core is bonded and coupled to the inner surface of the fiber-reinforced composite material layer. At least one mounting connector is disposed on the fiber-reinforced composite material layer for connecting the structure to the vehicle body sheet metal.
[0007] Preferably, the mounting connector is a mounting plate, which is fixedly connected to the fiber-reinforced composite material layer by rivets.
[0008] Preferably, it also includes a foaming adhesive, which is disposed between the fiber-reinforced composite material layer and the body sheet metal to enhance the connection strength and sealing performance between the structure and the body sheet metal after being heated and foamed.
[0009] Preferably, the energy-absorbing foam core is made of one of PU foam, PEI foam, PMI foam or EPA foam, with a density range of 0.1~0.6 g / cm³.
[0010] Preferably, the fiber-reinforced composite material layer (1) is made of either glass fiber composite material or carbon fiber composite material, with a density range of 1.6~2.7 g / cm³.
[0011] Preferably, the adhesiveness generated by the energy-absorbing foam core during the foaming process directly bonds to the inner surface of the fiber-reinforced composite material layer, forming a composite structure with bonding force.
[0012] The beneficial effects of this invention are as follows: By combining a high-strength energy-absorbing foam core with a fiber-reinforced composite material shell, this invention significantly reduces the overall weight of the car door sill structure, overcoming the drawbacks of traditional extruded aluminum materials being too heavy, and effectively meeting the lightweight requirements of modern automobiles. During a collision, the foam core and the composite material layer deform synergistically through interfacial adhesion, jointly absorbing and dispersing impact energy, greatly improving the structure's energy absorption efficiency, thereby effectively reducing intrusion into the passenger compartment and enhancing side-impact safety.
[0013] Meanwhile, the structure achieves a high-strength and high-stability connection with the vehicle body through the installation of connectors (such as welding plates) and expanding foam. The expanding foam cures after baking, which not only strengthens the connection points, but also makes the door sill structure and the side of the vehicle body form an integrated force transmission path, further improving the overall rigidity and collision performance, effectively protecting the safety of key components such as the bottom battery pack, and also has good manufacturability and assemblability. Attached Figure Description
[0014] Figure 1 This is a structural diagram of the present invention. Detailed Implementation
[0015] In the description of this disclosure, it should be understood that the terms “center,” “upper,” “lower,” “front,” “rear,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” and “outer,” etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this disclosure and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this disclosure.
[0016] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this disclosure, unless otherwise stated, "a plurality of" means two or more.
[0017] In the description of this disclosure, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.
[0018] The specific embodiments of this utility model are described in detail below with reference to the accompanying drawings and preferred embodiments. Example 1
[0019] like Figure 1 As shown, the present invention provides a lightweight structure for automobile door sills that combines foam and fiber-reinforced composite materials, which mainly consists of a fiber-reinforced composite material layer 1, an energy-absorbing foam core 2, mounting plates 3, and rivets 4.
[0020] The fiber-reinforced composite material layer 1 is formed from carbon fiber prepreg using a molding process into a U-shaped shell structure that matches the inner cavity of the car door sill. Its density is approximately 1.8 g / cm³, serving as the main load-bearing skeleton. The energy-absorbing foam core 2 is made of PMI foam with a density of 0.3 g / cm³. Through the adhesiveness generated during its foaming process, it is encapsulated and firmly bonded to the cavity formed by the fiber-reinforced composite material layer 1, together forming a complete composite energy-absorbing unit. The mounting weld piece 3 is a standard steel part, fixedly connected to the fiber-reinforced composite material layer 1 at a predetermined position via rivets 4, for subsequent welding and installation to the car door sill sheet metal.
[0021] The assembly and working principle of this structure are as follows: First, the pre-formed fiber-foam composite unit is initially positioned and spot-welded to the side sill beam of the vehicle body using mounting plates 3. During the electrophoretic baking process, the high-temperature environment inside the vehicle body further strengthens the interface between the energy-absorbing foam core 2 and the fiber-reinforced composite material layer 1. In the event of a side collision, the impact force is transmitted to this structure through the door. The fiber-reinforced composite material layer 1 provides high-rigidity support and absorbs energy through buckling deformation. Simultaneously, the internal PMI foam core 2 is compressed and collapses, working together to efficiently absorb collision energy, thereby significantly reducing intrusion into the passenger compartment and achieving a balance between lightweighting and safety. Example 2
[0022] Based on Example 1, this example further adds the application of expanding foam 5 to improve the connection performance and overall integrity.
[0023] Specifically, before the main structure is pre-positioned onto the body sheet metal by installing the welding tabs 3, epoxy resin foam 5 is applied to the bonding area between the fiber-reinforced composite material layer 1 and the body sheet metal. Subsequently, in the baking oven after the body has undergone electrophoresis (temperature typically between 150℃ and 200℃), the foam 5 expands and foams due to heat, fully filling all assembly gaps between the fiber-reinforced composite material layer 1 and the body sheet metal, and after curing, forms a high-strength, high-rigidity adhesive layer. This structure not only provides a secondary connection in addition to the mechanical connection (welding tabs 3), but also significantly enhances the connection rigidity and strength between this structure and the body, allowing the sill assembly to participate in force transmission and energy absorption earlier and more effectively in a collision, forming an integral crash-resistant structure, especially with superior protection for the battery pack underneath. Example 3
[0024] This embodiment is a further extension of the above structure. The fiber-reinforced composite material layer 1 can also be made of glass fiber composite material using RTM (resin transfer molding) to reduce costs. The energy-absorbing foam core 2 can be replaced with PU foam or PEI foam with a density in the range of 0.1~0.6 g / cm³. The mounting connector 3 is not limited to welding tabs; it can also adopt a bolt connection structure or a snap-fit connection structure integrally formed with the fiber-reinforced composite material layer 1, depending on design requirements. The foaming adhesive 5 can also be baked and foamed separately during the final assembly stage, without relying on the electrophoretic baking process. These modifications all fall within the protection scope of this utility model.
[0025] It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of this utility model, and these improvements and modifications should also be considered within the scope of protection of this utility model.
Claims
1. A lightweight structure combining foam and fiber-reinforced composite materials for automotive door sills, characterized in that, include: A fiber-reinforced composite material layer (1) constitutes the outer shell of the structure; An energy-absorbing foam core (2) is filled and wrapped in the internal cavity of the fiber-reinforced composite material layer (1), and the outer surface of the energy-absorbing foam core (2) is bonded and coupled to the inner surface of the fiber-reinforced composite material layer (1). At least one mounting connector (3) is disposed on the fiber-reinforced composite material layer (1) for connecting the structure to the body sheet metal.
2. The lightweight structure of a foam and fiber-reinforced composite material combination for a car door sill according to claim 1, characterized in that, The mounting connector (3) is a mounting plate, which is fixedly connected to the fiber-reinforced composite material layer (1) by a rivet (4).
3. A lightweight structure of a foam and fiber-reinforced composite material combination for a car door sill according to claim 1 or 2, characterized in that, It also includes a foaming adhesive (5), which is disposed between the fiber-reinforced composite material layer (1) and the body sheet metal, and is used to enhance the connection strength and sealing of the structure and the body sheet metal after being heated and foamed.
4. The lightweight structure of a foam and fiber-reinforced composite material combination for a car door sill according to claim 1, characterized in that, The energy-absorbing foam core (2) is made of one of PU foam, PEI foam, PMI foam or EPA foam, with a density range of 0.1~0.6 g / cm³.
5. A lightweight structure of a foam and fiber-reinforced composite material combination for an automobile door sill according to claim 1, characterized in that, The fiber-reinforced composite material layer (1) is made of either glass fiber composite material or carbon fiber composite material, with a density range of 1.6~2.7 g / cm³.
6. A lightweight structure of a foam and fiber-reinforced composite material combination for a car door sill according to claim 1, characterized in that, The adhesiveness generated during the foaming process of the energy-absorbing foam core (2) directly bonds to the inner surface of the fiber-reinforced composite material layer (1), forming a composite structure with bonding force.