Composite-to-metal joint structure and method

Abstract

The application discloses a composite material and metal component connecting structure, which comprises a metal insert, one end of the metal insert is embedded into a composite material component, and the other end of the metal insert is provided with an extended first connecting surface and a metal component connecting structure. The composite material and metal component connecting structure and connecting method provided by the application adopt the metal insert combined with the insert welding method, realize the connecting effect with the connecting strength being greater than the composite material strength, and improve the combination strength of the composite material and the metal insert through structure and process optimization, so that the overall connecting strength of the composite material component is realized.

Description

Technical Field

[0001] This invention relates to the field of manufacturing composite materials and metal components, specifically to a connection structure and method for composite materials and metal components, which is particularly applicable to the manufacturing of subframes. Background Technology

[0002] Currently, the most common methods for connecting thermoplastic composite materials include adhesive bonding, riveting, bolting, and hot melt welding. However, all of these methods have problems such as insufficient strength or stress concentration in terms of connection strength.

[0003] 1. The adhesive materials are generally epoxy resin, acrylate, polyurethane, etc., and their bonding strength is generally within 35MPa. 2. Hot melt welding uses lasers, hot gases, etc. to melt and fuse the base material at high temperatures, and its connection strength can reach about 90% of the base material, generally below 50MPa; 3. Riveting and bolting connections are made through mechanical structures, which pose a risk of crushing to composite materials. In addition, the connection relies on discrete rivets or screws to transfer loads, resulting in significant stress concentration on the rivets or screws and the nearby composite materials, thus creating a risk of failure.

[0004] For connections of composite structural components subjected to high loads and high stresses, the aforementioned connection methods or structures are insufficient to meet strength requirements. This is particularly true in vehicle subframe manufacturing, where composite materials and metal components are often spliced ​​together to meet lightweight and strength requirements. Therefore, the connection strength between the composite materials and metal components directly affects the overall structural strength of the subframe. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a connection structure for composite materials and metal components, including a metal insert. One end of the metal insert is embedded in the composite material component, and the other end has an extended first connecting surface that connects to the metal component.

[0006] Furthermore, the metal insert includes a first connecting surface, a second connecting surface, and a third connecting surface connected in sequence, the second connecting surface protruding from the first connecting surface and the third connecting surface, and the third connecting surface being embedded in the composite material component.

[0007] Furthermore, the depth to which the third connecting surface is embedded in the composite material component is not less than the connection depth between the first connecting surface and the metal component.

[0008] Furthermore, the metal insert is a U-shaped hollow cross-section component, and the first connecting surface, the second connecting surface, and the third connecting surface are all U-shaped connecting surfaces.

[0009] Furthermore, an engagement expansion groove is deployed on the third connecting surface, and the engagement expansion groove is filled with composite material from the composite material component.

[0010] Furthermore, the meshing expansion groove is a circular hole, a protrusion, or a groove distributed on the third connecting surface.

[0011] Furthermore, the meshing expansion groove is a groove distributed on the third connecting surface. The groove is distributed along the U-shaped surface of the third connecting surface and is isolated between the bending sections of the U-shaped surface. The opening directions of adjacent grooves are opposite.

[0012] A method for connecting composite materials and metal components is also proposed, employing the aforementioned connection structure, and specifically including the following steps: S1, the metal insert is pre-embedded in the injection molding mold of the composite material component, and the third connecting surface is embedded in the end of the injection molding mold of the composite material component, and the integral injection molding end is embedded in the composite material component with the metal insert. S2, weld the first connecting surface of the metal insert to the end of the metal component to complete the connection between the composite material and the metal component.

[0013] Furthermore, in step S2, laser welding is used to weld the first connecting surface and the end of the metal component.

[0014] Furthermore, in step S2, before welding, the surface roughness of the first connecting surface is improved by sandblasting or barbing, and hot melt adhesive is sprayed to improve the bonding strength of the first connecting surface.

[0015] Compared with the prior art, the technical solution of this application has the following beneficial effects: The connection structure and connection method of composite materials and metal components proposed in this invention adopts the method of metal insert combined with insert welding to achieve a connection effect with a connection strength greater than that of composite materials, and improves the bonding strength of composite materials and metal inserts through structural and process optimization, thereby realizing the overall connection strength of composite components. Attached Figure Description

[0016] Figure 1 Schematic diagram of the split structure connecting composite materials and metal components; Figure 2 : Schematic diagram of the side structure of the connection structure between composite materials and metal components; Figure 3 Cross-sectional view of a metal insert embedded in a composite material component. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] A composite material and metal component connection structure includes a metal insert 1, one end of which is embedded in the composite material component, and the other end has an extended first connection surface 11 that connects to the metal component.

[0019] In this embodiment, see Figures 1-3 The metal insert 1 can be pre-embedded during the molding of the composite component 4, so that its first connecting surface 11 is exposed after molding. The structure of the metal insert 1 can be designed to match the surface structure of the composite material and the metal component 5 that need to be connected. The first connecting surface 11 is made of metal and can be connected to the metal component 5 by welding, so as to achieve a connection strength greater than that of the composite material, thereby achieving the overall connection strength of the composite component.

[0020] In a more preferred embodiment, the metal insert 1 includes a first connecting surface 11, a second connecting surface 12, and a third connecting surface 13 connected in sequence. The second connecting surface 12 protrudes from the first connecting surface 11 and the third connecting surface 13, and the third connecting surface 13 is embedded in the composite material component 4. When connecting the metal component 5 and the composite material, the third connecting surface 13 is completely embedded in the composite material component 4, and the composite material is flush with the second connecting surface 12. The first connecting surface 11 serves as a welding surface and is welded to the metal component 5. After welding, the metal component 5 overlaps the first connecting surface 11, and the connected metal component 5 is flush with the composite material component 4 and the second connecting surface 12. Furthermore, the second connecting surface 12 serves as a transition surface, located between the connected metal component 5 and the composite material component 4. When welding the metal component 5 and the first connecting surface 11, the second connecting surface 12 serves as a heat transfer transition surface to reduce the temperature rise of the third connecting surface 13 embedded in the composite material component 4, preventing excessive heat deformation of the third connecting surface 13 and affecting its connection strength in the composite material component 4.

[0021] In a more preferred embodiment, the depth to which the third connecting surface 13 is embedded in the composite material component 4 is not less than the connection depth between the first connecting surface 11 and the metal component 5. In this embodiment, in order to improve the connection strength between the metal insert 1 and the composite material component 4, the third connecting surface 13 is configured to have a larger area and a greater connection depth, resulting in a higher connection strength after being embedded in the composite material component 4.

[0022] In a more preferred embodiment, the metal insert 1 is a U-shaped hollow cross-section component, and the first connecting surface 11, the second connecting surface 12, and the third connecting surface 13 are all U-shaped connecting surfaces. In the molding and assembly of some composite material subframes, the U-shaped hollow cross-section is a commonly used structural form; therefore, the metal insert 1 can be configured with each connecting surface into the required profile structure according to needs.

[0023] In a more preferred embodiment, an engagement expansion groove 131 is provided on the third connecting surface 13, and the engagement expansion groove 131 is filled with the composite material of the composite component 4. In this embodiment, the engagement expansion groove 131 is intended to further improve the connection strength between the third connecting surface 13 and the composite component 4. During the injection molding process, the composite material fills the engagement expansion groove 131. After demolding and cooling, because the coefficient of thermal expansion of the metal is higher than that of the composite material, the metal shrinks more than the composite material, and the metal engagement expansion groove 131 clamps the composite material portion to form a reliable connection.

[0024] In a more preferred embodiment, the meshing expansion groove 131 is a circular hole, a protrusion, or a groove distributed on the third connecting surface 13.

[0025] In a more preferred embodiment, see Figure 3 The meshing expansion groove 131 is a groove distributed on the third connecting surface 13. The groove is distributed along the U-shaped surface of the third connecting surface 13, with isolation between the bending sections of the U-shaped surface. The opening directions of adjacent grooves are opposite. In this embodiment, the groove will be configured as a reverse-displaced blind groove structure. After the composite material is filled into the groove, a reverse-displaced meshing structure will be formed, which can further improve the connection strength between the composite material and the third connecting surface 13. The groove will extend as far as possible to the edge of the third connecting surface 13, so that the meshing structure has a larger meshing area, while the isolation between the bending sections of the U-shaped surface ensures that the U-shaped metal insert 1 still has reliable structural strength. At the same time, the groove does not completely penetrate the third connecting surface 13 but is a blind groove, so the third connecting surface 13 is still a continuous metal connecting surface with better structural strength.

[0026] Another implementation method will be proposed based on the above connection structure, which specifically includes the following steps: S1, the metal insert 1 is pre-embedded in the injection molding mold of the composite material component 4, and the third connecting surface 13 is embedded in the end of the injection molding mold of the composite material component 4, and the integral injection molding end is embedded in the metal insert 1 composite material component 4. S2, weld the first connecting surface 11 of the metal insert 1 to the end of the metal component 5 to complete the connection between the composite material and the metal component 5.

[0027] In a more preferred embodiment, laser welding is used to weld the first connecting surface 11 and the end of the metal component 5. Specifically, in this embodiment, a laser welding machine is used to reduce the heat source range and decrease the impact of temperature transfer on the composite material bonding surface. Appropriate laser power and welding speed are selected based on the different thicknesses of the metal component and its distance from the composite material to control the temperature of the composite bonding surface below 150°C.

[0028] In a more preferred embodiment, in step S2, before welding, the surface roughness of the first connecting surface 11 is improved by sandblasting or barbing, and hot melt adhesive is sprayed to improve the bonding strength of the first connecting surface 11.

[0029] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0030] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A connection structure for composite materials and metal components, characterized in that, It includes a metal insert (1), one end of which is embedded in a composite material component, and the other end has an extended first connecting surface (11) connected to the metal component.

2. The composite material and metal component connection structure as described in claim 1, characterized in that, The metal insert (1) includes a first connecting surface (11), a second connecting surface (12) and a third connecting surface (13) connected in sequence. The second connecting surface (12) protrudes from the first connecting surface (11) and the third connecting surface (13), and the third connecting surface (13) is embedded in the composite material component.

3. The composite material and metal component connection structure as described in claim 2, characterized in that, The depth to which the third connecting surface (13) is embedded in the composite material component is not less than the connection depth between the first connecting surface (11) and the metal component.

4. The composite material and metal component connection structure as described in claim 3, characterized in that, The metal insert (1) is a U-shaped hollow cross-section component, and the first connecting surface (11), the second connecting surface (12) and the third connecting surface (13) are all U-shaped connecting surfaces.

5. The composite material and metal component connection structure as described in claim 4, characterized in that, A meshing expansion groove (131) is deployed on the third connecting surface (13), and the meshing expansion groove (131) is filled with composite material in the composite material component.

6. The composite material and metal component connection structure as described in claim 5, characterized in that, The meshing expansion groove (131) is a round hole, a protrusion, or a groove distributed on the third connecting surface (13).

7. The composite material and metal component connection structure as described in claim 6, characterized in that, The meshing expansion groove (131) is a groove distributed on the third connecting surface (13). The groove is distributed along the U-shaped surface of the third connecting surface (13) and is separated between the bending sections of the U-shaped surface. The opening directions of adjacent grooves are opposite.

8. A method for connecting composite materials and metal components, employing the connection structure described in any one of claims 2 to 8, characterized in that, Specifically, it includes the following steps: S1, embed the metal insert (1) in the injection molding mold of the composite material component, and embed the third connecting surface (13) into the end of the injection molding mold of the composite material component, and embed the metal insert (1) into the composite material component in the integral injection molding end. S2, weld the first connecting surface (11) of the metal insert (1) to the end of the metal component to complete the connection between the composite material and the metal component.

9. The method for connecting composite materials and metal components as described in claim 8, characterized in that, In step S2, laser welding is used to weld the first connecting surface (11) and the end of the metal component.

10. The method for connecting composite materials and metal components as described in claim 9, characterized in that, In step S2, before welding, the surface of the first connecting surface (11) is sandblasted or barbed to improve the roughness of the first connecting surface (11), and hot melt adhesive is sprayed to improve the bonding strength of the first connecting surface (11).

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