A connecting mechanism lower connector

Abstract

This utility model relates to the field of joint connections and discloses a lower joint of a connection mechanism. The lower joint includes a connecting cylinder, a fork-shaped wing, and reinforcing ribs. The connecting cylinder is fixed to the top of the fork-shaped wing and is used to connect with a lifting rod. The fork-shaped wing is used to connect with a crossbeam. The reinforcing ribs longitudinally span across the connecting cylinder and the fork-shaped wing. Reinforcing ribs are provided on both sides of the lower joint and are symmetrical to each other. This component adopts a one-piece milling forming process. Its symmetrical reinforcing rib design optimizes the force flow path and significantly reduces stress concentration between the connecting cylinder and the fork-shaped wing. At the same time, the milling process eliminates defects such as internal porosity and shrinkage, thereby comprehensively improving fatigue resistance and service life.

Description

Technical Field

[0001] This utility model relates to the field of connector connection, specifically to a lower connector of a connection mechanism. Background Technology

[0002] Existing low-altitude aircraft such as UAVs, eVTOLs, flying cars, and air-to-ground integrated vehicles include a flight frame and a ground-based body. The flight frame is the core part of the low-altitude aircraft responsible for flight, including the fuselage, wings, and power system, and is the main structure for achieving aerial flight. The ground-based body is the part of the low-altitude aircraft responsible for ground transportation. The low-altitude aircraft also includes a connection module for connecting the flight frame and the ground-based body. The connection module includes a boom, which connects the two through the longitudinal beams of the flight frame and the crossbeams of the ground-based body. The bottom end of the boom is connected to a lower connector for connecting to the crossbeams. This lower connector is a key component in the low-altitude aircraft's connection system. Its structural performance determines the operational safety and structural reliability of the low-altitude aircraft, and plays a core supporting role in the stable operation of the low-altitude aircraft under multiple operating conditions, including flight and ground transportation.

[0003] Currently, the lower joint structures of existing low-altitude aircraft connection modules are mainly divided into two categories: the first is a plate-welded structure, which is formed by stamping a single metal sheet and then welding several reinforcing ribs to improve the local structural stiffness and strength; the second is a cast structure, which is formed directly as a whole using casting technology to ensure structural integrity. For plate-welded structures, the heat-affected zone during welding easily leads to the deterioration of the mechanical properties of the metal material, and significant residual stress concentration easily occurs inside the structure, greatly weakening its fatigue resistance. At the same time, due to the inherent limitations of traditional welding processes, the layout of the reinforcing ribs in this type of structure often relies on engineering experience and is not optimized in conjunction with multi-condition load transfer characteristics, making it difficult to achieve a reasonable distribution of load paths and easily leading to local overload problems. For cast structures, although they have better structural integrity, they suffer from excessive weight, which is detrimental to improving the power-to-weight ratio of low-altitude aircraft. Furthermore, the casting process easily forms defects such as porosity and shrinkage within the structure, which directly affect the structural fatigue performance and increase the risk of structural fracture. Utility Model Content

[0004] The present invention aims to provide a lower connector for a connecting mechanism to solve the problem of insufficient reliability and lifespan of existing lower connectors.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a lower connector of a connecting mechanism, the lower connector including a connecting cylinder, a fork-shaped wing, and a reinforcing rib. The connecting cylinder is fixed to the top of the fork-shaped wing and is used to connect with the lifting rod. The fork-shaped wing is used to connect with the crossbeam. The reinforcing rib spans the connecting cylinder and the fork-shaped wing longitudinally. Reinforcing ribs are provided on both sides of the lower connector and are symmetrical to each other.

[0006] The beneficial effects of this solution are as follows: the connecting cylinder, the fork-shaped wing, and the reinforcing ribs are all integrally formed and manufactured by milling. The milling process symmetrically mills the reinforcing ribs on both sides. The bridging setting of the reinforcing ribs can significantly improve the force flow transmission path and reduce the stress concentration phenomenon at the connection between the connecting cylinder and the fork-shaped wing. In addition, the milled workpiece will not form defects such as porosity and shrinkage within the structure, which improves the fatigue resistance of the lower joint, reduces the risk of fracture, and extends the service life of the lower joint.

[0007] Preferably, as an improvement, the fork-shaped wing includes a top plate and a wing plate vertically disposed on the bottom surface of the top plate. The wing plate includes a first wing plate and a second wing plate symmetrically disposed on both sides of the bottom surface of the top plate.

[0008] The beneficial effects are as follows: A C-shaped groove is formed between the top plate, the first wing plate, and the second wing plate of the forked wing section. The C-shaped groove allows the crossbeam of the land vehicle to be embedded and connected. This is mainly achieved by the direct contact and fixed connection between the crossbeam and the bottom surface of the wing plates on both sides and the top plate. This structural form creates a stress dispersion zone between the three components of the first wing plate, the second wing plate, and the top plate, which significantly improves the force transmission path. At the same time, the symmetrical layout of the first wing plate and the second wing plate ensures that the load is evenly distributed from both sides, thereby effectively reducing local stress concentration and improving the stability and durability of the overall structure.

[0009] Preferably, as an improvement, the reinforcing rib includes a first rib, a second rib, and a third rib. The first rib is vertically fixed along the center of the connecting cylinder axis, and the second rib is vertically fixed along the center of the flange. The first rib and the second rib are integrally formed and coplanar. The third rib is disposed between the connecting cylinder and the top plate and forms an angle of 90° with the first rib.

[0010] The beneficial effects are as follows: the connecting module connects the flight frame and the land vehicle. The flight frame exerts axial tension on the lower joint through the connecting module's boom, while the land vehicle exerts radial support force on the lower joint due to the bump load during the journey on the ground. At this time, the central setting of the first rib and the second rib provides the premise that they are coplanar. The first rib and the second rib are integrally formed and coplanar, forming a continuous force-bearing structure that runs through the connecting cylinder and the wing plate. This allows the axial tension and radial support force to be directly and continuously transmitted through the rib, reducing stress concentration points and improving the overall bending and shear resistance.

[0011] Preferably, as an improvement, the lower connector has symmetrically provided connecting holes on both sides, and an annular boss is provided around the periphery of the connecting holes. The annular boss is integrally formed with the lower connector, and the annular boss is coaxially arranged with the corresponding connecting hole.

[0012] The beneficial effects are as follows: the connecting hole adopts a rough boring-semi-fine boring-fine reaming process, and the connection between the annular boss and the lower connector is set with a rounded transition, thereby reducing the stress concentration at the root of the annular boss. The annular boss, connecting hole, and lower connector are integrally milled and formed, rather than welded later. This not only avoids the material property degradation caused by welding heat, but also ensures the structural integrity of the component. When the bolt is pre-tightened or subjected to working loads, such as the tension of the hanger rod or the support force of the crossbeam, the radial compressive load on the hole wall is first transmitted to a larger area of ​​the lower connector body through the annular boss, thereby reducing the local compressive stress. Combined with the overall design structure of the lower connector, this load can be further diffused to the stress dispersion area of ​​the fork-shaped wing, thereby avoiding the local accumulation of compressive stress around the hole. This complete force flow path ultimately significantly improves the compressive strength of the hole wall and the fatigue life of the structure.

[0013] Preferably, as an improvement, the connecting hole includes a plurality of first bolt holes formed in the connecting cylinder and a plurality of second bolt holes formed in the wing plate.

[0014] Preferably, as an improvement, the plurality of second bolt holes are all standardized bolt holes, and the plurality of second bolt holes are arranged in an array on the wing plate.

[0015] The beneficial effects are: the wing plate can be flexibly connected to beams of various widths, thicknesses or mounting hole requirements by replacing the adapter bolts of different lengths and specifications, without the need to design wing plate holes separately for beams of different specifications, which greatly expands the compatibility range of the lower connector and the beam and reduces the dependence on special accessories.

[0016] In addition, the standardized second bolt holes arranged in an array can make the bolts form uniform fastening points on the flange, disperse the load transmitted by the crossbeam, avoid local bolts from loosening or breaking due to stress concentration, and improve the long-term stability and reliability of the connection.

[0017] Preferably, as an improvement, the thickness of the reinforcing rib is greater than the thickness of its other areas at three specific locations: the connection between the reinforcing rib and the connecting cylinder, the connection between the reinforcing rib and the wing plate, and the area of ​​the reinforcing rib near the connecting hole on the wing plate.

[0018] The beneficial effects are as follows: Through finite element analysis and topology optimization, the reinforcing rib is designed as a variable thickness structure, with a greater thickness in high-stress areas (such as the connection with the connecting cylinder, the wing plate, and near the bolt holes), and a suitable reduction in thickness in low-stress areas (such as the middle). This scheme achieves a reasonable distribution of materials, significantly reducing weight while ensuring structural strength.

[0019] The beneficial effects of this variable-thickness reinforcing rib are as follows: First, it achieves a balance between high stiffness and lightweight, reducing weight and operational energy consumption while ensuring load-bearing safety. Second, its optimized morphology closely matches adjacent structures, forming a continuous and smooth force transmission path, effectively avoiding local stress concentration, thereby endowing the structure with higher stability and fatigue resistance. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the present invention installed on a low-altitude aircraft according to an embodiment of the present invention; Figure 2 for Figure 1 A partial structural diagram of the connecting module at point A in the middle; Figure 3 This is an isometric view of the connector structure in an embodiment of this utility model; Figure 4 for Figure 3 Front view of the middle and lower connector structure; Figure 5 for Figure 3 Left view of the structure of the lower connector; Figure 6 for Figure 3 Top view of the lower connector. Detailed Implementation

[0021] The following detailed description illustrates the specific implementation method: The reference numerals in the accompanying drawings include: low-altitude aircraft 1, flight frame 11, longitudinal beam 111, land-based body 12, crossbeam 121, connecting module 13, boom 14, upper connector 15, lower connector 16, connecting cylinder 2, fork-shaped wing 3, top plate 31, first wing plate 32, second wing plate 33, reinforcing rib 4, first rib 41, second rib 42, third rib 43, connecting hole 5, first bolt hole 51, second bolt hole 52.

[0022] Example like Figures 1-6The connecting mechanism shown includes a connecting cylinder 2 and a fork-shaped wing 3 fixed below the connecting cylinder 2. The fork-shaped wing 3 includes a top plate 31 and wing plates vertically and symmetrically fixed on both sides of the top plate 31. The wing plates include a first wing plate 32 and a second wing plate 33. The wing plates on both sides are integrally formed with the top plate 31, and the connection between the wing plates and the top plate 31 is rounded. The connecting cylinder 2 has a rectangular cross-section, and the bottom end of the connecting cylinder 2 is fixed to the upper surface of the top plate 31. The connection between the connecting cylinder 2 and the top plate 31 is also rounded. The connecting cylinder 2 is used to connect with the boom 14, and the fork-shaped wing 3 is used to connect with the crossbeam 121. A reinforcing rib 4 is longitudinally connected between the connecting cylinder 2 and the fork-shaped wing 3. Reinforcing ribs 4 are provided on both sides of the lower connector 16 and are symmetrical to each other. The reinforcing rib 4 includes a first rib 41, a second rib 42, and a third rib 43. The first rib 41 is vertically fixed along the center of the connecting cylinder 2, and the second rib 42 is vertically fixed along the center of the wing. The first rib 41 and the second rib 42 are integrally formed and coplanar.

[0023] The third rib 43 is located between the connecting cylinder 2 and the top plate 31, forming a 90° angle with the first rib 41. The connecting cylinder 2, the fork-shaped wing 3, and the reinforcing rib 4 are all integrally formed and manufactured by milling. The surface of the lower connector 16 is treated with micro-arc oxidation to form a dense ceramicized film layer. When the lower connector 16 is assembled with the crossbeam 121 or when the low-altitude aircraft 1 is impacted during takeoff and landing, the surface is prone to friction or slight collisions. The ceramicized film layer has a hardness of HV350 or higher, which can directly withstand the frictional loss during assembly and the slight stone impact during low-altitude takeoff and landing, avoiding surface scratches and dents, maintaining the flatness of the connection interface of the lower connector 16, and reducing stress concentration caused by surface damage, thereby indirectly extending the overall service life of the lower connector 16.

[0024] like Figures 3-6 As shown, the thickness of the reinforcing rib 4 is greater than the thickness of its other areas at three specific locations (not shown in the figure). These three specific locations are: the connection between the reinforcing rib 4 and the connecting cylinder 2, the connection between the reinforcing rib 4 and the wing plate, and the area of ​​the reinforcing rib 4 near the connecting hole 5 on the wing plate. Connecting holes 5 are also symmetrically provided on both sides of the lower connector 16. An annular boss is provided around the hole of the connecting hole 5. The annular boss is integrally formed with the lower connector 16. The annular boss is coaxially arranged with the corresponding connecting hole 5. The connecting hole 5 includes several first bolt holes 51 opened in the connecting cylinder 2 and several second bolt holes 52 opened in the wing plate. The several second bolt holes 52 are all standardized bolt holes. The several second bolt holes 52 are arranged in an array on the wing plate.

[0025] Mounting slots are provided at the connection between the wing plate and the top plate 31, and at the connection between the reinforcing rib 4 and the lower connector 16. The mounting slots are used to install sensors that detect the stress state at the connection. The connection module 13 also includes an upper connector 15 connected to the top of the boom 14. The upper connector 15 is also set as a fork-shaped wing. The upper connector 15 is used to connect with the longitudinal beam 111. In terms of materials, the upper connector 15 is made of high-strength titanium alloy, which has excellent mechanical properties and fatigue resistance, and can withstand the complex alternating loads of the low-altitude aircraft 1 in flight and land conditions.

[0026] The specific implementation process is as follows: During assembly, the connecting cylinder 2 of the lower connector 16 is fixed to the bottom end of the boom 14, the fork-shaped wing 3 is detachably connected to the crossbeam 121 through the array of standardized second bolt holes 52, the variable thickness structure of the reinforcing rib plate 4 strengthens the key stress area, the micro-arc oxide film layer improves the corrosion resistance and wear resistance of the lower connector 16, and the sensor in the mounting slot monitors the stress at the connection in real time to ensure stable load transfer of the connecting module 13 during the operation of the low-altitude aircraft 1.

[0027] The installation steps for the connecting boom 14 are as follows: First, precisely align the upper connector 15 with the connecting components on the low-altitude aircraft 1 and the boom 14 to ensure a tight fit between the connecting surfaces. Then, sequentially pass the bolt assemblies through the pre-set bolt holes on the upper connector 15 body, the low-altitude aircraft 1, and the boom 14, and apply pre-tightening force to the bolts to create sufficient friction and clamping force between the contact interfaces. This ultimately achieves a reliable fixed connection between the low-altitude aircraft 1 and the land vehicle 12. This connection method is a detachable structure, which not only ensures the stability of the connection but also facilitates subsequent maintenance, repair, and rapid separation of the low-altitude aircraft 1 and the land vehicle 12.

[0028] During installation, first align the lower connector 16 with the crossbeam 121 and tighten it with four M8×25 high-strength bolts to a torque of 40 N·m; then insert the hanger 14 into the connecting cylinder 2 and connect it with eight Φ10 high-strength bolts to a torque of 60 N·m; finally, install the sensor and connect it to the monitoring system. This implementation avoids traditional manufacturing defects through integral molding, optimizes the structural design to improve stress distribution, and enhances surface properties through special treatment processes, achieving a comprehensive performance improvement of lightweight, high reliability, and long service life.

[0029] The above descriptions are merely embodiments of this utility model. Commonly known technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solution of this utility model. These modifications and improvements should also be considered within the scope of protection of this utility model, and will not affect the effectiveness of the implementation of this utility model or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A lower connector for a connecting mechanism, characterized in that: The lower connector is a one-piece molded structure, which includes a connecting cylinder for connecting with the boom, a fork-shaped wing for connecting with the crossbeam, and a reinforcing rib for enhancing the connection strength. The connecting cylinder is integrally located at the top of the fork-shaped wing, and the reinforcing rib spans longitudinally between the connecting cylinder and the fork-shaped wing to form an integrated and reinforced connection between the connecting cylinder and the fork-shaped wing.

2. The lower connector according to claim 1, characterized in that: The fork-shaped wing includes a top plate and a pair of wing plates vertically disposed on the bottom surface of the top plate. The wing plates are symmetrically distributed on both sides of the top plate and are referred to as the first wing plate and the second wing plate, respectively.

3. The lower connector according to claim 2, characterized in that: The reinforcing ribs include a first rib, a second rib, and a third rib. The first rib is vertically fixed along the center of the connecting cylinder axis, and the second rib is vertically fixed along the center of the flange. The first and second ribs are integrally formed and coplanar. The third rib is located between the connecting cylinder and the top plate and forms an angle of 90° with the first rib.

4. The lower connector according to claim 3, characterized in that: The lower connector has symmetrical connecting holes on both sides, and an annular boss is provided around the connecting holes. The annular boss is integrally formed with the lower connector, and the annular boss is coaxially set with the corresponding connecting hole.

5. The lower connector according to claim 4, characterized in that: The connecting holes include several first bolt holes in the connecting cylinder and several second bolt holes in the wing plate.

6. The lower connector according to claim 5, characterized in that: Several second bolt holes are standardized bolt holes, and an array of several second bolt holes is arranged on the wing plate.

7. The lower connector according to claim 4, characterized in that: The thickness of the reinforcing rib is greater than that of other areas of the rib at three specific locations: the connection between the reinforcing rib and the connecting cylinder, the connection between the reinforcing rib and the wing plate, and the area of ​​the reinforcing rib near the connection hole on the wing plate.

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