Reinforcing structure and fender
By designing an L-shaped structure of vertical reinforcement plates, horizontal reinforcement plates and flat reinforcement plates on the fender, combined with connection and bonding components, the problems of insufficient fender stiffness and rust are solved, achieving efficient stiffness improvement and simplified installation.
Patent Information
- Application Number
- CN202510861114.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-25
- Publication Date
- 2025-09-23
AI Technical Summary
In the prior art, automobile fenders have insufficient rigidity, resulting in deformation and poor matching accuracy. In addition, the reinforcing pads are expensive, prone to rust, and difficult to operate.
An L-shaped structure consisting of vertical reinforcement plates, horizontal reinforcement plates and flat reinforcement plates is adopted, combined with connection components, bonding components and weight reduction components to enhance the overall stiffness and stability of the fender.
It improves the stiffness and matching accuracy of the fender, reduces production costs, avoids rust, simplifies the installation process, and enhances the appearance quality and durability of the entire vehicle.
Smart Images
Figure CN120681235A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of automobile front fenders, and particularly relates to a reinforcement structure and a fender. Background Art
[0002] With the rapid development of the automotive industry, the pace of car product upgrades is accelerating, and styles and styling are becoming increasingly diverse. In automobile manufacturing, the quality of automotive exterior panels plays a crucial role in the overall quality of the vehicle, and fenders are a typical representative component.
[0003] Automobile fenders are three-dimensional curved structures with complex and varied shapes. They must overlap and align with multiple components within the vehicle body, including the hood, front bumper, and headlights, placing extremely high demands on appearance. However, fender sheet metal thickness typically ranges from 0.6mm to 0.8mm. Given their large area and thinness, fenders are prone to softening, and in severe cases, even permanent deformation, compromising the overall vehicle appearance and the precision of their fit with adjacent components.
[0004] In terms of vehicle styling, fenders primarily overlap and match the front hood, front bumper, and headlights. When dividing the seams between the fender and hood, and between the fender and headlights, multiple factors must be considered, including overall aesthetics, styling, and minimizing the difficulty of matching. Specifically, the front end of the fender is divided into two sections by three seams: a longitudinal seam separating the fender from the hood; a transverse seam separating the fender from the front bumper; and a central arc-shaped seam where the headlights are inserted into the fender, separating the fender from the headlights.
[0005] Between the longitudinal and arc-shaped seams, a long, pointed, dagger-shaped cantilever forms on the upper fender. Because this angle is typically narrow and long, and limited by the headlight housing's space, it's impossible to locate a mounting point at the front. This results in extremely low stiffness at the front end of the fender's angle, making it prone to sagging and deformation, severely impacting the alignment with the hood and headlights. Furthermore, between the conventional arc-shaped seam and the transverse seam, a long, pointed cantilever forms on the lower fender. Because it's located below the headlights, the matching seam is obscured by the headlights, making it relatively undemanding. Considering cost factors, a dedicated reinforcement structure is generally not necessary.
[0006] Currently, existing technologies include adding structural reinforcement pads to the inner side of the fender to increase fender stiffness. After being heated and hardened in the paint shop oven, these pads can improve the sheet metal rigidity of the covered area. However, this solution has numerous drawbacks: First, the cost of the reinforcement pads is higher than the sheet metal, increasing production costs. Second, during the painting process, the pads obstruct the electrophoresis and paint treatment of the bonded areas, making them susceptible to rust. Furthermore, this method fails to strengthen the fender's front headlight or front bumper mounting surfaces. Applying the pads to long, sharp corners is also difficult, and the pad's size and positioning are relatively difficult to control.
[0007] Therefore, in order to effectively solve the above-mentioned problems of automobile fenders, improve the stiffness of fenders, ensure their good matching with adjacent components, reduce production costs, and avoid rust and other problems, it is of great practical significance to develop a more effective reinforcement structure. Summary of the Invention
[0008] The purpose of the present invention is to provide a reinforcement structure and fender to solve the technical defects in the prior art, such as the cost of the reinforcement pad is higher than that of the sheet metal, which increases the production cost; at the same time, during the painting process, due to the obstruction of the reinforcement pad, the bonding parts cannot be electrophoretically and painted, which easily causes rust problems; finally, it is impossible to improve the strength of the mounting surface of the fender headlights or front bumper, the operation of sticking the reinforcement pad on long sharp corners is also difficult, and the size and positioning of the reinforcement pad are relatively difficult to control.
[0009] In order to achieve the above object, the present invention adopts the following technical solutions: In a first aspect, a reinforcement structure is provided, comprising: vertical reinforcement plates; A horizontal reinforcing plate connected to the bottom of one side of the vertical reinforcing plate to form an L-shaped structure with the vertical reinforcing plate; A flat reinforcing plate is provided on the other side of the vertical reinforcing plate, and forms a structure with one end open and the other end closed between the vertical reinforcing plate and the horizontal reinforcing plate; A connecting assembly is provided at one end of the horizontal reinforcing plate away from the vertical reinforcing plate and is used to connect the fender; The bonding components are arranged around the flat reinforcement plate.
[0010] Furthermore, the connection component includes a first connection component and a second connection component, and the first connection component and the second connection component are arranged crosswise.
[0011] Furthermore, the first connecting component includes a plurality of mounting holes, and the plurality of mounting holes are sequentially spaced apart; The second connecting component includes a plurality of positioning through holes, and the plurality of positioning through holes are respectively arranged between two adjacent mounting through holes.
[0012] Furthermore, the bonding assembly includes a plurality of glue coating grooves, which are arranged around the planar reinforcing plate, and each glue coating groove has a different shape.
[0013] Furthermore, the horizontal reinforcement plate is provided with a first mounting hole and a second mounting hole. The first mounting hole and the second mounting hole are located below the connecting assembly and are connected to the fender via rivets.
[0014] Furthermore, a third mounting hole is formed at one end of the vertical reinforcing plate away from the horizontal reinforcing plate, and the third mounting hole is fixed to the fender via a clip nut.
[0015] Furthermore, it also includes a weight-reducing component, which is arranged on the flat reinforcing plate.
[0016] Furthermore, the weight-reducing component includes a plurality of weight-reducing holes, and the plurality of weight-reducing holes are arranged at intervals along the length direction of the planar reinforcing plate.
[0017] Furthermore, the vertical reinforcement plate is a long strip structure.
[0018] In a second aspect, a fender is provided. The fender is a T-shaped structure, and the bottom of the vertical end thereof has an opening. The inner side of the opening is installed with the reinforcement structure as described above.
[0019] Compared with the prior art, the present invention has the following beneficial effects: The L-shaped structure formed by connecting the vertical reinforcement plate and the horizontal reinforcement plate can provide strong support at specific parts of the fender, effectively resist the external force acting on the fender, and enhance the overall stiffness of the fender, especially for the longer dagger-shaped sharp-angled cantilever formed on the upper part of the fender. Due to the low stiffness at the front end of the sharp corner, it is prone to sagging and deformation. The L-shaped structure can disperse and withstand forces from different directions, thereby reducing deformation and sagging at the sharp corner, ensuring a good match between the fender and components such as the front hood and headlights, and improving the appearance quality of the entire vehicle; in addition, this reinforcement structure can be specially designed in combination with the characteristic styling surface of the fender, and applied to the weak local surfaces of each thin plate for local reinforcement; this reinforcement structure design unit is flexible and changeable, has low weight cost, occupies little space, and is easy to install; finally, the flat reinforcement plate, the vertical reinforcement plate and the horizontal reinforcement plate together form a one-end open and one-end closed structure, which further increases the integrity and stability of the reinforcement structure. This structure can expand the coverage of the reinforcement effect, so that when the fender is subjected to external force, the energy can be more effectively transmitted and dispersed within the structure, rather than concentrated in local areas and causing deformation, thereby comprehensively improving the stiffness of the fender and reducing the possibility of the fender becoming soft and permanently deformed as a whole. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.
[0021] Figure 1 A schematic diagram of the reinforcement structure provided by the present invention; Figure 2 A schematic diagram of the fender structure provided by the present invention; Figure 3 A front view of the reinforcement structure provided by the present invention; Figure 4 A right side view of the reinforcement structure provided by the present invention; Figure 5 A three-dimensional diagram of the reinforcement structure provided by the present invention; Figure 6 A schematic diagram of the assembly of the reinforcement structure and rivets provided by the present invention; Figure 7 A schematic diagram of a horizontal reinforcement plate in the reinforcement structure provided by the present invention; Figure 8 A schematic diagram of the bonding components in the reinforcement structure provided by the present invention; Among them: 1. Reinforcement structure; 101. Horizontal reinforcement plate; 102. Vertical reinforcement plate; 103. Plane reinforcement plate; 2. Fender; 3. Rivet; 4. Clip nut; 001. First mounting hole; 002. First positioning hole; 003. Second mounting hole; 004. Second positioning hole; 005. Third mounting hole; 006. Third mounting hole; 007. Flanged edge; 008. First glue groove; 009. First weight-reducing hole; 010. Second glue groove; 011. Second weight-reducing hole; 013. Third weight-reducing hole; 014. Third glue groove; 015. Fourth glue groove; 016. Fifth glue groove; 017. Second mounting hole; 018. First mounting hole; 019. Sixth glue groove; 020. Seventh glue groove. DETAILED DESCRIPTION
[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.
[0023] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.
[0024] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.
[0025] In the description of the embodiments of the present invention, it should be noted that if the terms "upper," "lower," "horizontal," "inner," etc. appear, the orientation or positional relationship indicated is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the inventive product is typically placed when in use. These terms are merely for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first," "second," etc. are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.
[0026] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.
[0027] In the description of the embodiments of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.
[0028] To address the technical deficiencies mentioned in the background art, this embodiment provides a reinforcement structure and a fender. The present invention is further described in detail below with reference to the accompanying drawings. In a first aspect, an embodiment of the present invention provides a reinforcement structure, such as Figures 1-8As shown, the structure includes a vertical reinforcing plate 102; a horizontal reinforcing plate 101 connected to the bottom of one side of the vertical reinforcing plate 102, forming an L-shaped structure with the vertical reinforcing plate 102; a planar reinforcing plate 103, disposed on the other side of the vertical reinforcing plate 102, forming a structure with one end open and the other closed between the vertical reinforcing plate 102 and the horizontal reinforcing plate 101. The vertical reinforcing plate 102 and the planar reinforcing plate 103 form a flange 007; a connecting assembly, located at the end of the horizontal reinforcing plate 101 away from the vertical reinforcing plate 102, for connecting to the fender 2; and an adhesive assembly, arranged around the planar reinforcing plate 103. In this reinforcement structure 1, the L-shaped structure formed by the vertical reinforcing plate 102 and the planar reinforcing plate 103 provides strong support at the opening of the fender 2, effectively resisting external forces acting on the fender 2 and enhancing the overall rigidity of the fender 2. In particular, for the longer, dagger-shaped cantilever with sharp corners formed on the upper part of the fender 2, since the front end of the sharp corner has low stiffness and is prone to sagging and deformation, the L-shaped structure can disperse and withstand forces from different directions, thereby reducing deformation and sagging at the sharp corners, ensuring a good match between the fender 2 and components such as the front hood and headlights, and improving the appearance quality of the entire vehicle.
[0029] In addition, the planar reinforcement plate 103, the vertical reinforcement plate 102 and the horizontal reinforcement plate 101 together form an open-end and closed-end structure, which further increases the integrity and stability of the reinforcement structure 1, and can expand the coverage of the reinforcement effect, so that when the fender 2 is subjected to external force, the energy can be more effectively transmitted and dispersed within the structure, rather than concentrated in a local area to cause deformation, thereby comprehensively improving the stiffness of the fender 2 and reducing the possibility of the fender 2 becoming soft and permanently deformed as a whole.
[0030] The end of the horizontal reinforcement plate 101 away from the vertical reinforcement plate 102 is provided with a connecting assembly for connecting to the fender 2, making the connection between the reinforcement structure and the fender 2 more convenient and stable. Through the connecting assembly, the reinforcement structure 1 can be quickly and accurately positioned and installed in the appropriate position on the fender 2, reducing the complexity and time consumption during the installation process and improving assembly efficiency. At the same time, the reasonable connection method can ensure that the reinforcement structure 1 and the fender 2 are tightly connected, ensuring the effective reinforcement effect.
[0031] Adhesive components are arranged around the flat reinforcing plate 103, which is bonded to the fender 2 by bonding, thereby avoiding the problem of rust caused by the reinforcement pad blocking the bonding part from electrophoresis and painting when the structural reinforcement pad is affixed to the inner side of the fender 2 in the prior art. The adhesive components can ensure good sealing and bonding strength between the reinforcing structure 1 and the fender 2, and will not affect the painting treatment on the surface of the fender 2, thereby ensuring the quality and durability of the appearance of the fender 2 and improving the quality level of the entire vehicle.
[0032] Specifically, the connection assembly includes a first connection assembly and a second connection assembly, which are arranged crosswise. Specifically, the first connection assembly includes multiple mounting holes, which are spaced apart from each other. The second connection assembly includes multiple positioning holes, which are respectively arranged between two adjacent mounting holes. As can be seen from the figure, the mounting holes include a first mounting hole 001, a second mounting hole 003, and a third mounting hole 005; the positioning holes include a first positioning hole 002 and a second positioning hole 004.
[0033] In the above structure, the first connecting component is provided with a plurality of mounting holes spaced apart in sequence, and the second connecting component is provided with a positioning hole between two adjacent mounting holes, so that a multi-point connection is formed between the reinforcing structure 1 and the fender 2. During the driving process of the vehicle, the fender 2 will be subjected to various complex external forces. The multi-point connection can effectively disperse these external forces to each connection point, avoiding excessive stress on a single connection point, thereby greatly improving the stability and reliability of the connection and reducing the risk of loosening or damage at the connection part. Secondly, the combined connection of multiple mounting holes and positioning holes enhances the overall rigidity between the reinforcing structure 1 and the fender 2. When the vehicle is subjected to vibration or impact, this multi-point connection structure can better resist deformation, maintain a tight connection between the reinforcing structure 1 and the fender 2, ensure that the fender 2 can maintain stable performance under various working conditions, and reduce problems such as poor matching between the fender 2 and adjacent components and abnormal noise caused by vibration and impact.
[0034] In addition, the positioning through-hole is arranged between two adjacent mounting through-holes, providing a precise positioning reference for the installation of the reinforcement structure 1 on the fender 2; during the assembly process, workers can quickly and accurately position the reinforcement structure 1 to the appropriate position of the fender 2 through the positioning through-hole, and then use the mounting through-hole to fix it, which can greatly reduce assembly errors, improve assembly accuracy, and ensure that the relative position between the reinforcement structure 1 and the fender 2 is accurate, thereby ensuring good matching between the fender 2 and adjacent components.
[0035] The bonding assembly includes multiple gluing slots arranged around the planar reinforcement plate, each with a different shape. Specifically, they include a first gluing slot 008, a second gluing slot 010, a third gluing slot 014, a fourth gluing slot 015, a fifth gluing slot 016, a sixth gluing slot 019, and a seventh gluing slot 020. Each gluing slot has a different shape, allowing the most appropriate gluing slot shape to be selected based on different locations around the planar reinforcement plate, different stress conditions, and the characteristics of the interface with the fender 2. Different shapes provide varying bonding contact areas and bonding stress distribution patterns, thereby better adapting to various complex bonding requirements, ensuring a secure bond between the planar reinforcement plate 103 and the fender 2, enhancing bonding strength, and reducing the possibility of loosening or falling off the reinforcement structure due to weak bonding.
[0036] When the planar reinforcement plate 103 is subjected to external forces, the differently shaped adhesive grooves can constrain the adhesive from multiple directions and angles, increasing the peel resistance of the bonding interface and making the connection between the reinforcement structure 1 and the fender 2 more reliable. Even when subjected to significant vibration and impact during vehicle operation, the bond can remain stable. Furthermore, because each adhesive groove has a different shape, the adhesive will experience different stress distributions within the bonding area formed within each groove during the bonding process. This differentiated stress distribution effectively disperses the overall bonding stress across multiple differently shaped adhesive grooves, preventing stress concentration in a single localized area. This reduces the risk of bonding failure due to excessive local stress and improves the durability and reliability of the bonded structure.
[0037] In this embodiment, the horizontal reinforcing plate 101 is further provided with a first mounting hole 018 and a second mounting hole 017. These first and second mounting holes 018 and 017 are located below the connecting assembly and are both connected to the fender 2 via rivets 3. In addition to the connecting assembly, the horizontal reinforcing plate 101 also has the first and second mounting holes 018 and 017, and is connected to the fender 2 via rivets 3, creating a dual connection method combining the connecting assembly and the rivets 3. This dual connection significantly enhances the connection strength between the reinforcing structure 1 and the fender 2, making the connection more secure and reliable. During vehicle operation, even when subjected to significant vibration, impact, or complex external forces, the reinforcing structure 1 and the fender 2 can effectively prevent loosening or detachment, ensuring that the reinforcing structure 1 can continue to stably enhance the stiffness of the fender 2. The first and second mounting holes 018 and 017 are located below the connecting assembly, sharing the connecting function with the connecting assembly and more evenly distributing the stress acting at the connection between the reinforcing structure 1 and the fender 2. When subjected to external force, the stress will not be concentrated on a certain connection point, but will be dispersed and transmitted through multiple connection points, reducing the risk of failure of a single connection point due to excessive stress and improving the reliability and durability of the entire connection system.
[0038] In this embodiment, a third mounting hole 006 is defined at the end of the vertical reinforcing plate 102 remote from the horizontal reinforcing plate 101. This third mounting hole 006 is secured to the fender 2 via a clip nut 4. The clip nut 4 secures the third mounting hole 006 at the end of the vertical reinforcing plate 102 remote from the horizontal reinforcing plate 101 to the fender 2. The clip nut 4 provides excellent fastening performance and resistance to loosening. During vehicle operation, the fender 2 is subject to various vibrations and impacts. The clip nut 4 securely locks the connection, preventing vibration-induced loosening between the third mounting hole 006 and the fender 2. This ensures a tight and stable connection between the vertical reinforcing plate 102 and the fender 2, thereby further enhancing the stiffness-enhancing effect of the reinforcement structure 1 on the fender 2.
[0039] Through the fixation of the third mounting hole 006 and the clip nut 4, the connection between the vertical reinforcement plate 102 and the fender 2 is more secure, so that the reinforcement structure 1 and the fender 2 form a more complete whole. This integrity helps to improve the mechanical properties of the entire structure, so that the force can be transmitted more evenly between the reinforcement structure 1 and the fender 2, reducing stress concentration and structural deformation problems caused by loose local connections, and further improving the stability and reliability of the structure.
[0040] The reinforcement structure 1 also includes a weight-reducing assembly, which is mounted on the planar reinforcement plate 103. The weight-reducing assembly includes multiple weight-reducing holes spaced along the length of the planar reinforcement plate 103. The vertical reinforcement plate 102 is an elongated strip, and the weight-reducing holes include a first weight-reducing hole 009, a second weight-reducing hole 011, and a third weight-reducing hole 013. By installing the weight-reducing assembly on the planar reinforcement plate 103, the weight of the reinforcement structure itself can be effectively reduced. As a vehicle is a holistic system, the weight of each component contributes to the overall weight of the vehicle. Reducing the weight of the reinforcement structure 1 directly reduces the overall weight of the vehicle. According to the principles of physics, for the same power output, the lighter the vehicle, the less inertia it must overcome, thereby reducing the load on the engine or motor and reducing energy consumption. For gasoline-powered vehicles, this helps improve fuel economy and reduce fuel costs for drivers. For electric vehicles, it can increase the vehicle's range, reduce charging frequency, and improve user convenience.
[0041] In a second aspect, a fender 2 is provided. The fender 2 is a T-shaped structure, and the bottom of the vertical end thereof has an opening. The reinforcing structure 1 as described above is installed inside the opening.
[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit its scope of protection. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that after reading the present invention, those skilled in the art may still make various changes, modifications or equivalent substitutions to the specific implementation methods of the invention, but these changes, modifications or equivalent substitutions are all within the scope of protection of the pending claims of the invention.
Claims
1. A reinforcement structure, characterized in that: include: vertical reinforcement plates; A horizontal reinforcing plate connected to the bottom of one side of the vertical reinforcing plate to form an L-shaped structure with the vertical reinforcing plate; A flat reinforcing plate is provided on the other side of the vertical reinforcing plate, and forms a structure with one end open and the other end closed between the vertical reinforcing plate and the horizontal reinforcing plate; A connecting assembly is provided at one end of the horizontal reinforcing plate away from the vertical reinforcing plate and is used to connect the fender; The bonding components are arranged around the flat reinforcement plate.
2. The reinforcement structure according to claim 1, characterized in that The connection assembly includes a first connection assembly and a second connection assembly, and the first connection assembly and the second connection assembly are arranged crosswise.
3. The reinforcement structure according to claim 2, characterized in that The first connecting component includes a plurality of mounting holes, and the plurality of mounting holes are sequentially spaced apart; The second connecting component includes a plurality of positioning through holes, and the plurality of positioning through holes are respectively arranged between two adjacent mounting through holes.
4. The reinforcement structure according to claim 1, characterized in that The bonding assembly includes a plurality of glue coating grooves, which are arranged around the plane reinforcing plate, and each glue coating groove has a different shape.
5. The reinforcement structure according to claim 1, characterized in that The horizontal reinforcing plate is further provided with a first mounting hole and a second mounting hole. The first mounting hole and the second mounting hole are located below the connecting assembly and are connected to the fender via rivets.
6. The reinforcement structure according to claim 1, characterized in that A third mounting hole is formed at one end of the vertical reinforcing plate away from the horizontal reinforcing plate, and the third mounting hole is fixed to the fender via a clip nut.
7. The reinforcement structure according to claim 1, characterized in that It also includes a weight reduction component, which is arranged on the flat reinforcement plate.
8. The reinforcement structure according to claim 7, characterized in that The weight-reducing component includes a plurality of weight-reducing holes, and the plurality of weight-reducing holes are arranged at intervals along the length direction of the planar reinforcing plate.
9. The reinforcement structure according to claim 8, characterized in that The vertical reinforcement plate is a long strip structure.
10. A fender, characterized in that: The fender is a T-shaped structure, and the bottom of the vertical end thereof has an opening, and the reinforcing structure according to any one of claims 1 to 9 is installed inside the opening.