Steel-aluminum mixed structure semitrailer connecting device and method
The semi-trailer connecting device, with its steel-aluminum hybrid structure and staggered layering design, solves the problem of balancing lightweight and load-bearing strength, achieving a lightweight and high-strength connection between the traction pin and the traction seat, and reducing fuel consumption and corrosion risk.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-31
- Publication Date
- 2026-03-27
AI Technical Summary
Existing semi-trailer connecting devices struggle to balance lightweight design and load-bearing capacity, resulting in excessive weight, corrosion at wear points, and cracking at welded joints, which negatively impact connection stability and safety.
The design adopts a steel-aluminum hybrid structure. The traction pin and traction seat are connected by alternating layers of boron steel core and aluminum alloy layer, combined with inverted trapezoidal concave ring and convex ring. PEEK isolation layer is used to block galvanic corrosion, and it is reinforced by self-piercing riveting and epoxy structural adhesive. Bolts and nuts are used for fastening.
This design achieves lightweighting of the traction pin and traction seat, improves connection strength and tensile strength, reduces weight and fuel consumption, extends device life, and reduces corrosion risk.
Smart Images
Figure CN121734531A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of semi-trailer technology, and in particular to a steel-aluminum hybrid structure semi-trailer connection device and method. Background Technology
[0002] The semi-trailer coupling device includes a drawbar and a drawbar seat. The drawbar is a crucial component connecting the semi-trailer to the tractor and bearing traction force. It connects to the drawbar seat and is typically forged from carbon steel or alloy steel. The drawbar seat not only bears a portion of the semi-trailer's vertical weight but also functions as a towing mechanism and steering mechanism. In existing technologies, to ensure the required connection strength and stability, all-steel coupling devices are usually chosen. The drawbar and drawbar typically weigh 300-500 kg. Manufacturing the coupling device requires multiple welding processes. The welded areas of the all-steel structure are prone to porosity and cracks, leading to stress concentration and cracking after prolonged exposure to vibration. Furthermore, the all-steel cast drawbar assembly is significantly more susceptible to corrosion during daily wear, increasing the risk of breakage under excessive stress. By designing a weight-reducing system for the semi-trailer connecting device, for every 1kg reduction in weight, the effective load capacity can be increased by 0.02 tons, and for every 100kg reduction in weight, fuel consumption can be saved by 0.3-0.5L / 100km. Summary of the Invention
[0003] To address the technical problem of balancing lightweight and load-bearing strength in semi-trailer connecting devices, this invention provides a steel-aluminum hybrid structure semi-trailer connecting device, including a drawbar and a drawbar pin, wherein the drawbar pin includes an mounting part and a pin part.
[0004] Both the mounting part and the pin part are provided with boron steel cores at their centers, and the boron steel cores of the two parts are connected to each other and integrally formed.
[0005] The outer side of the boron steel core is provided with a second isolation layer, a second aluminum alloy layer, a third isolation layer and a second boron steel layer from the inside to the outside. The boron steel core and the second aluminum alloy layer are separated by the second isolation layer, and the second aluminum alloy layer and the second boron steel layer are separated by the third isolation layer.
[0006] The surface of the boron steel core is uniformly provided with a plurality of inverted trapezoidal recessed rings. On the surface of the second isolation layer close to the boron steel core, an inverted trapezoidal protruding ring that matches the inverted trapezoidal recessed ring is fixedly connected. On the other side of the second isolation layer away from the boron steel core, a plurality of inverted trapezoidal recessed rings are also provided.
[0007] On the surface of the second aluminum alloy layer close to the second isolation layer, an inverted trapezoidal protrusion ring that matches the inverted trapezoidal recessed ring is fixedly connected, and multiple inverted trapezoidal recessed rings are also provided on the surface of the second aluminum alloy layer away from the second isolation layer.
[0008] The third isolation layer has an inverted trapezoidal protrusion ring that matches the inverted trapezoidal recessed ring on the surface of the third isolation layer that is close to the second aluminum alloy layer. The third isolation layer also has multiple inverted trapezoidal recessed rings on the other side of the surface that is away from the second aluminum alloy layer.
[0009] On the surface of the second boron steel layer close to the third isolation layer, an inverted trapezoidal protrusion ring that matches the inverted trapezoidal recessed ring is fixedly connected.
[0010] Preferably, in the above technical solution, the traction seat includes a connecting plate and a shell. Both the connecting plate and the shell are layered structures and each includes a first boron steel layer. A first isolation layer and a first aluminum alloy layer are sequentially provided on the outer side of the first boron steel layer. A plurality of inverted trapezoidal grooves are uniformly provided on the upper and lower surfaces of the first boron steel layer. A plurality of inverted trapezoidal protrusions are uniformly fixedly connected to the upper and lower surfaces of the first isolation layer. The inverted trapezoidal grooves on the first boron steel layer cooperate with the inverted trapezoidal protrusions on the first isolation layer. The first aluminum alloy layer has an inverted trapezoidal groove matching the inverted trapezoidal protrusions on one side surface near the first isolation layer.
[0011] Preferably, in the above technical solution, self-piercing rivets are arranged crosswise on the upper surface of the first aluminum alloy layer, and the rivet heads penetrate the first aluminum alloy layer and self-lock and fix to the first boron steel layer.
[0012] Preferably, in the above technical solution, the center of the traction seat is provided with a locking claw, the locking claw is constructed as a layered structure and includes a third boron steel layer. On the outer side of the third boron steel layer, from the inside out, there are a first epoxy structural adhesive, a third aluminum alloy layer, a second epoxy structural adhesive and a fourth boron steel layer. The third boron steel layer and the third aluminum alloy layer are separated by the first epoxy structural adhesive, and the third aluminum alloy layer and the fourth boron steel layer are separated by the second epoxy structural adhesive.
[0013] Preferably, in the above technical solution, each side of the locking claw is provided with a set of screws and nuts, and both ends of the third boron steel layer, the third aluminum alloy layer, the second epoxy structural adhesive and the first epoxy structural adhesive are provided with through holes to ensure that the bolt can be threadedly connected to the nut after passing through each of the through holes.
[0014] Preferably, in the above technical solution, the bolt's shank is fitted with a nylon sheath.
[0015] Preferably, in the above technical solution, the first isolation layer, the second isolation layer and the third isolation layer are made of PEEK.
[0016] The first aluminum alloy layer, the second aluminum alloy layer and the third aluminum alloy layer are made of 7075-T6 aluminum alloy.
[0017] Preferably, in the above technical solution, the traction seat is fixedly installed on the rear frame of the tractor, the pin portion of the traction pin is a cylindrical metal pin, the mounting portion of the traction pin is fixedly installed at the bottom of the front end of the semi-trailer, and the locking claw is rotatably connected to the middle of the traction seat.
[0018] A method for connecting a steel-aluminum hybrid semi-trailer is also disclosed. First, the towing seat, towing pin, and locking claw in the steel-aluminum hybrid semi-trailer connecting device are manufactured. Then, the towing seat and towing pin are fixedly installed on the corresponding positions on the semi-trailer. Next, under the drive of the semi-trailer, the towing seat and the pin portion of the towing pin are aligned. Then, the locking claw is opened, and the concave ring portion of the pin portion is inserted into the towing seat. Finally, the locking claw is locked to realize the connection of the steel-aluminum hybrid semi-trailer connecting device.
[0019] Compared with the prior art, the present invention has the following beneficial effects:
[0020] The mounting part and the center of the insertion part of the traction pin in this invention adopt an integrally cast boron steel core. The outer shell is composed of boron steel layers and aluminum alloy layers arranged in an alternating layered manner. The contact surface between them has an inverted trapezoidal recessed ring and a matching inverted trapezoidal raised ring, which allows the boron steel layer and the aluminum alloy layer to fit tightly together. This allows the traction pin to have both high strength and a significant weight reduction. The connecting plate and the outer shell of the traction seat adopt a method of sandwiching a boron steel layer between two aluminum alloy layers. The contact surface between them not only has an inverted trapezoidal groove and a matching inverted trapezoidal raised strip, but also uses SPR (self-piercing riveting) to further reinforce the traction seat by interlacing the upper and lower surfaces. This significantly improves the tensile strength of the traction seat while reducing its weight. The locking claw in the traction seat (i.e., the part that fixes the traction pin) adopts a method of stacking boron steel layers and aluminum alloy layers. After the layers are bonded and fixed with epoxy structural adhesive, they are tightened with bolts and nuts, which also achieves both high strength and weight reduction.
[0021] The contact surface between the aluminum alloy layer and the boron steel is provided with PEEK (polyether ether ketone), which has good tensile and bending strength. On the one hand, it can reduce weight, and on the other hand, it can prevent galvanic corrosion between the aluminum alloy layer and the boron steel, thus extending the service life of the connection device. Attached Figure Description
[0022] Figure 1A schematic diagram of the overall structure of a steel-aluminum hybrid semi-trailer connecting device provided by the present invention;
[0023] Figure 2 A schematic diagram of the internal structure of the traction pin of a steel-aluminum hybrid semi-trailer connecting device provided by the present invention;
[0024] Figure 3 A schematic diagram of the outer shell structure of the traction seat of a steel-aluminum hybrid semi-trailer connecting device provided by the present invention;
[0025] Figure 4 for Figure 2 A partially enlarged view of the internal structure of the central traction pin;
[0026] Figure 5 A schematic diagram of the internal structure of the locking claw of the traction seat of a steel-aluminum hybrid semi-trailer connecting device provided by the present invention;
[0027] Figure 6 This is a schematic diagram of the internal structure of the locking claw through hole of a steel-aluminum hybrid semi-trailer connecting device provided by the present invention.
[0028] Explanation of key figure labels:
[0029] 1-Traction seat, 2-Traction pin, 3-Locking claw, 4-Self-piercing rivet, 11-First boron steel layer, 12-First aluminum alloy layer, 13-First isolation layer, 21-Boron steel core, 22-Second isolation layer, 23-Second aluminum alloy layer, 24-Second boron steel layer, 25-Pin part, 26-Mounting part, 27-Third isolation layer, 31-Third boron steel layer, 32-Third aluminum alloy layer, 33-First epoxy structural adhesive, 34-Bolt, 35-Nut, 36-Nylon sheath, 37-Through hole, 38-Second epoxy structural adhesive, 39-Fourth boron steel layer, 111-Inverted trapezoidal groove, 121-Inverted trapezoidal protrusion, 211-Inverted trapezoidal recessed ring, 221-Inverted trapezoidal raised ring. Detailed Implementation
[0030] 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.
[0031] Example 1
[0032] like Figures 1-2As shown, the present invention discloses a steel-aluminum hybrid structure semi-trailer connecting device, including a drawbar 1 and a drawbar pin 2. The drawbar pin 2 includes a mounting portion 26 and a pin portion 25. Both the mounting portion 26 and the pin portion 25 have a boron steel core 21 at their centers, and the boron steel cores 21 of both are interconnected and integrally formed. From the inside out, the outer side of the boron steel core 21 is provided with a second isolation layer 22, a second aluminum alloy layer 23, a third isolation layer 27, and a second boron steel layer 24. The boron steel core 21 and the second aluminum alloy layer 23 are separated by the second isolation layer 22, and the second aluminum alloy layer 23 and the second boron steel layer 24 are separated by the third isolation layer 27. The surface of the boron steel core 21 is uniformly provided with a plurality of inverted trapezoidal recessed rings 211. On the surface of the second isolation layer 22 close to the boron steel core 21, an inverted trapezoidal protruding ring 221 matching the inverted trapezoidal recessed ring 211 is fixedly connected; the other surface of the second isolation layer 22 away from the boron steel core 21 is also provided with a plurality of inverted trapezoidal recessed rings 211. On the surface of the second aluminum alloy layer 23 close to the second isolation layer 22, an inverted trapezoidal protruding ring 221 matching the inverted trapezoidal recessed ring 211 is fixedly connected; the other surface of the second aluminum alloy layer 23 away from the second isolation layer 22 is also provided with a plurality of inverted trapezoidal recessed rings 211. On the surface of the third isolation layer 27 close to the second aluminum alloy layer 23, an inverted trapezoidal protruding ring 221 matching the inverted trapezoidal recessed ring 211 is fixedly connected; the other surface of the third isolation layer 27 away from the second aluminum alloy layer 23 is also provided with a plurality of inverted trapezoidal recessed rings 211. On the surface of the second boron steel layer 24, close to the third isolation layer 27, an inverted trapezoidal protruding ring 221, matching the inverted trapezoidal recessed ring 211, is fixedly connected. Currently, most fixed connections between different metals are made by welding. After welding, the metal surface may experience reduced fixing strength due to the recessed base material at the weld edge, resulting in undercut. Furthermore, metal accumulation on the weld surface and visible circular holes can lead to localized brittle fracture. The inverted trapezoidal recessed ring 211 interlocks with the inverted trapezoidal protruding ring 221 on its contact surface, achieving a layered fixed connection. This ensures the connection strength between them, avoiding surface undercut, weld beads, and surface porosity caused by welding. It also avoids the increased overall weight of the traction pin 2 caused by other connection methods (such as insulated bolt connections or plated fasteners), thus preventing the achievement of weight reduction.
[0033] In this embodiment, as Figure 4 , 5As shown, the traction seat 1 includes a connecting plate and a shell. Both the connecting plate and the shell have a layered structure and each includes a first boron steel layer 11. A first isolation layer 13 and a first aluminum alloy layer 12 are sequentially provided on the outer side of the first boron steel layer 11. Multiple inverted trapezoidal grooves 111 are uniformly provided on the upper and lower surfaces of the first boron steel layer 11. Multiple inverted trapezoidal protrusions 121 are uniformly fixedly connected to the upper and lower surfaces of the first isolation layer 13. The inverted trapezoidal grooves 111 on the first boron steel layer 11 cooperate with the inverted trapezoidal protrusions 121 on the first isolation layer 13. On the side of the first aluminum alloy layer 12 closest to the first isolation layer 13, there is an inverted trapezoidal groove 111 that matches the inverted trapezoidal protrusions 121. The first isolation layer 13 and the second isolation layer 22 are made of PEEK. The standard electrode potential of metallic aluminum is -1.66V, while that of metallic steel (taking low-carbon steel as an example) is -0.44V. When they come into contact, a potential difference of 1.22V is formed, causing electrons to flow from aluminum (anode) to steel (cathode). An oxidation reaction occurs on the aluminum surface, while a reduction reaction occurs on the steel surface. When the ambient humidity is greater than 60%, an electrolytic film forms, and the corrosion rate increases exponentially (e.g., the corrosion rate in coastal areas is 10 times higher than in dry areas). The first isolation layer 13, the second isolation layer 22, and the third isolation layer 27 are made of PEEK (polyetheretherketone), and PEEK has a volume resistivity of 10 Ω·cm. 16 The PEEK insulating pad, measuring Ω·cm, is used between the first insulating layer 13 and the second insulating layer 22. This effectively prevents contact between the boron steel and the aluminum alloy through physical barrier, significantly reducing galvanic corrosion. The first aluminum alloy layer 12 and the second aluminum alloy layer 23 are made of 7075-T6 aluminum alloy. 7075-T6 is a high-strength aluminum alloy, where T6 indicates a state after solution treatment and artificial aging. This heat treatment significantly improves the strength of the aluminum alloy. Compared to 6061-T6, 7075-T6 in the same state has an 84% increase in tensile strength, reaching 572 MPa, and an 82% increase in yield strength, reaching 503 MPa. In this embodiment, 7075-T6 provides high tensile and yield strength while reducing material weight, decreasing the overall weight of the traction seat 1 by 35% to 40%.
[0034] Self-piercing rivets 4 are arranged crosswise on the upper surface of the first aluminum alloy layer 12. The heads of the self-piercing rivets 4 penetrate the first aluminum alloy layer 12 and self-lock into the first boron steel layer 11. In addition to being self-locked by the inverted trapezoidal protrusions 121 and inverted trapezoidal grooves 111, the upper and lower surfaces of the connecting plate and the outer shell of the traction seat 1 are also fixed by the SPR (self-piercing riveting) process. SPR is a cold connection technology that does not require pre-drilling. The rivets are directly pierced through the upper material by stamping and expand in the lower material to form a mechanical interlock. The connecting plate and the outer shell after self-piercing riveting have better stability. Compared with the combination of a single aluminum alloy layer and a boron steel layer, the double aluminum alloy layer can provide greater tensile strength and yield strength. At the same time, the self-piercing riveting of the upper, lower and surface layers can improve the connection strength of the aluminum alloy layer and the boron steel layer on the one hand, and reduce the self-piercing riveting points on the outer surface on the other hand, making the appearance more beautiful.
[0035] In this embodiment, the traction seat 1 has a locking claw 3 at its center. The locking claw 3 has a layered structure and includes a third boron steel layer 31. On the outer side of the third boron steel layer 31, from the inside out, are sequentially arranged a first epoxy structural adhesive 33, a third aluminum alloy layer 32, a second epoxy structural adhesive 38, and a fourth boron steel layer 39. The third boron steel layer 31 and the third aluminum alloy layer 32 are separated by the first epoxy structural adhesive 33, and the third aluminum alloy layer 32 and the fourth boron steel layer 39 are separated by the second epoxy structural adhesive 38. Each side of the locking claw 3 has a set of bolts 34 and nuts 35. Through holes 37 are opened at both ends of the third boron steel layer 31, the third aluminum alloy layer 32, the second epoxy structural adhesive 38, and the first epoxy structural adhesive 33 to ensure that the bolts 34 can be threadedly connected to the nuts 35 after passing through each through hole 37. A nylon sheath 36 is fitted around the outer periphery of the bolt 34. In this embodiment, the third aluminum alloy layer 32 is made of 7075-T6 aluminum alloy. The third aluminum alloy layer 32 and the third boron steel layer 31 are initially bonded and fixed together using epoxy structural adhesive 33. The resistivity of the epoxy structural adhesive 33 after curing is typically around 10 ohms. 12 ~10 16 The Ω·cm concentration effectively isolates the physical contact between the third aluminum alloy layer 32 and the third boron steel layer 31, blocking galvanic current and preventing galvanic corrosion. In addition, the dense layer formed after the epoxy resin cures can block water, oxygen, and ions (such as Cl-). -To prevent the formation of an electrolyte environment necessary for corrosion, after the bolt 34 passes through the third aluminum alloy layer 32 and the third boron steel layer 31, a nylon sleeve 36 is fitted onto the bolt shank to prevent galvanic corrosion in the through hole. The nylon sleeve 36 can be made of other materials with good insulation properties, such as fluororubber, silicone rubber, PA66, etc. The bolt 34 and nut 35 should also be made of lightweight materials that do not affect their curing strength. The towing seat 1 is fixedly installed on the rear frame of the tractor unit. The pin portion 25 of the towing pin 2 is a cylindrical metal pin. The mounting portion 26 of the towing pin 2 is fixedly installed at the bottom of the front end of the semi-trailer. The locking claw 3 is rotatably connected to the middle of the towing seat 1.
[0036] In the above embodiments, the surface of the aluminum alloy layer can also be treated with anti-corrosion methods such as anodizing, chemical conversion coating, and spray coating. The surface of the boron steel layer can also be treated with anti-corrosion methods such as electrophoretic coating and powder coating, so as to further reduce the risk of corrosion of the aluminum alloy layer and the boron steel layer and extend the service life of the steel-aluminum hybrid structure semi-trailer connection device.
[0037] Example 2
[0038] This invention provides a method for connecting steel-aluminum hybrid semi-trailers, based on the steel-aluminum hybrid semi-trailer connecting device of Embodiment 1, comprising the following steps: First, fabricating the traction seat 1, traction pin 2, and locking claw 3 in the steel-aluminum hybrid semi-trailer connecting device; then, fixing the traction seat 1 and traction pin 2 to corresponding positions on the semi-trailer; next, under the drive of the semi-trailer, aligning the traction seat 1 with the pin portion 25 of the traction pin 2; subsequently, opening the locking claw 3 and inserting the concave ring portion of the pin portion 25 into the traction seat 1; finally, locking the locking claw 3 to achieve the connection of the steel-aluminum hybrid semi-trailer connecting device.
[0039] Example 3
[0040] Existing semi-trailer connecting devices are mostly made of carbon steel or ordinary alloy steel. This embodiment compares the connecting device in Example 1 with existing connecting devices made of two different materials to compare the weight of connecting devices made of various materials and their fuel consumption per 100 kilometers for the same size. Based on the Ministry of Transport's comprehensive fuel consumption (L / 100 km), the following tests were conducted under the same vehicle model (FAW Jiefang-J7 heavy truck-CA4180P77K25E6), the same load (empty), the same road section, and the same weather conditions (same temperature and humidity):
[0041] Table 1. Fuel consumption per 100 kilometers for connecting devices made of different materials
[0042]
[0043] Semi-trailer connecting devices made of carbon steel or ordinary alloy steel have similar fuel consumption to those made of ordinary alloy steel, as the density of carbon steel is similar to that of ordinary alloy steel.
[0044] The steel-aluminum hybrid structure semi-trailer connecting device in Example 1 of this design adopts a lightweight design with the same size, and its weight is about 206.1 kg. Compared with the fuel consumption of carbon steel per 100 km, the lightweight design in Example 1 can save about 0.36~0.42 L / 100km of fuel.
[0045] The mounting and insertion parts of the traction pin in this invention utilize an integrally cast boron steel core. The outer shell consists of alternating layers of boron steel and aluminum alloy. The contact surfaces between these layers feature inverted trapezoidal recesses and matching inverted trapezoidal protrusions, ensuring a tight fit between the boron steel and aluminum alloy layers. This allows the traction pin to withstand high stress while minimizing its weight. The outer shell of the traction seat uses two aluminum alloy layers with a boron steel layer sandwiched in between. The contact surfaces not only feature inverted trapezoidal grooves and matching inverted trapezoidal protrusions, but are also further reinforced using SPR (self-piercing riveting) through an alternating upper and lower surface configuration. This significantly improves the tensile strength of the traction seat while reducing its weight. The locking claws (the part that secures the traction pin) in the traction seat also utilize alternating layers of boron steel and aluminum alloy. These layers are bonded together with epoxy structural adhesive and then secured with bolts and nuts, similarly achieving both high strength and lightweight design. This design reduces the overall weight of the traction pin and traction seat, solving the technical problem of balancing tensile strength, yield strength, and lightweighting. The lightweight design reduces fuel consumption, lowers vehicle operating costs, reduces carbon emissions and air pollutants, and promotes the construction of a low-carbon society.
[0046] The contact surface between the aluminum alloy layer and the boron steel is provided with PEEK (polyether ether ketone), which has good tensile and bending strength. On the one hand, it can reduce weight, and on the other hand, it can prevent galvanic corrosion between the aluminum alloy layer and the boron steel, thus extending the service life of the connection device.
[0047] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A steel-aluminum hybrid structure semi-trailer connecting device, characterized in that: It includes a traction seat (1) and a traction pin (2), wherein the traction pin (2) includes a mounting part (26) and a pin part (25); Both the mounting part (26) and the pin part (25) are provided with boron steel cores (21) at their centers, and the boron steel cores (21) of the two are connected to each other and integrally formed. The outer side of the boron steel core (21) is provided with a second isolation layer (22), a second aluminum alloy layer (23), a third isolation layer (27), and a second boron steel layer (24) from the inside out. The boron steel core (21) and the second aluminum alloy layer (23) are separated by the second isolation layer (22), and the second aluminum alloy layer (23) and the second boron steel layer (24) are separated by the third isolation layer (27). The surface of the boron steel core (21) is uniformly provided with a plurality of inverted trapezoidal recessed rings (211). On the surface of the second isolation layer (22) close to the boron steel core (21), an inverted trapezoidal protruding ring (221) matching the inverted trapezoidal recessed ring (211) is fixedly connected. On the other side of the second isolation layer (22) away from the boron steel core (21), a plurality of inverted trapezoidal recessed rings (211) are also provided. On the surface of the second aluminum alloy layer (23) close to the second isolation layer (22), an inverted trapezoidal protrusion ring (221) matching the inverted trapezoidal recessed ring (211) is fixedly connected. On the other side of the second aluminum alloy layer (23) away from the second isolation layer (22), multiple inverted trapezoidal recessed rings (211) are also provided. The third isolation layer (27) has an inverted trapezoidal protrusion ring (221) that matches the inverted trapezoidal recessed ring (211) on the surface of the third isolation layer (27) away from the second aluminum alloy layer (23). The third isolation layer (27) also has multiple inverted trapezoidal recessed rings (211) on the other side of the surface away from the second aluminum alloy layer (23). The second boron steel layer (24) has an inverted trapezoidal protrusion ring (221) that matches the inverted trapezoidal recessed ring (211) fixedly connected to the surface of the second boron steel layer (24) close to the third isolation layer (27).
2. The steel-aluminum hybrid structure semi-trailer connecting device according to claim 1, characterized in that: The traction seat (1) includes a connecting plate and a shell. Both the connecting plate and the shell are layered structures and each contains a first boron steel layer (11). The outer side of the first boron steel layer (11) is provided with a first isolation layer (13) and a first aluminum alloy layer (12). The upper and lower surfaces of the first boron steel layer (11) are uniformly provided with a plurality of inverted trapezoidal grooves (111). The upper and lower surfaces of the first isolation layer (13) are uniformly fixedly connected with a plurality of inverted trapezoidal protrusions (121). The inverted trapezoidal grooves (111) on the first boron steel layer (11) cooperate with the inverted trapezoidal protrusions (121) on the first isolation layer (13). The first aluminum alloy layer (12) has an inverted trapezoidal groove (111) that matches the inverted trapezoidal protrusions (121) on one side surface near the first isolation layer (13).
3. The steel-aluminum hybrid structure semi-trailer connecting device according to claim 2, characterized in that: Self-piercing rivets (4) are arranged crosswise on the upper surface of the first aluminum alloy layer (12). The heads of the self-piercing rivets (4) penetrate the first aluminum alloy layer (12) and are self-locked to the first boron steel layer (11).
4. The steel-aluminum hybrid structure semi-trailer connecting device according to claim 1, characterized in that: The center of the traction seat (1) is provided with a locking claw (3). The locking claw (3) has a layered structure and includes a third boron steel layer (31). On the outside of the third boron steel layer (31), from the inside out, there are a first epoxy structural adhesive (33), a third aluminum alloy layer (32), a second epoxy structural adhesive (38), and a fourth boron steel layer (39). The third boron steel layer (31) and the third aluminum alloy layer (32) are separated by the first epoxy structural adhesive (33), and the third aluminum alloy layer (32) and the fourth boron steel layer (39) are separated by the second epoxy structural adhesive (38).
5. The steel-aluminum hybrid structure semi-trailer connecting device according to claim 4, characterized in that: Each side of the locking claw (3) is provided with a set of bolts (34) and nuts (35). The third boron steel layer (31), the third aluminum alloy layer (32), the second epoxy structural adhesive (38) and the first epoxy structural adhesive (33) are provided with through holes (37) at both ends to ensure that the bolts (34) can be threaded to the nuts (35) after passing through each through hole (37).
6. The steel-aluminum hybrid structure semi-trailer connecting device according to claim 5, characterized in that: The bolt (34) is fitted with a nylon sheath (36) around its outer circumference.
7. The steel-aluminum hybrid structure semi-trailer connecting device according to claims 2 and 4, characterized in that: The first isolation layer (13), the second isolation layer (22) and the third isolation layer (27) are made of PEEK. The first aluminum alloy layer (12), the second aluminum alloy layer (23) and the third aluminum alloy layer (32) are made of 7075-T6 aluminum alloy.
8. The steel-aluminum hybrid structure semi-trailer connecting device according to claim 4, characterized in that: The traction seat (1) is fixedly installed on the rear frame of the tractor vehicle. The pin part (25) of the traction pin (2) is a cylindrical metal pin. The mounting part (26) of the traction pin (2) is fixedly installed at the bottom of the front end of the semi-trailer. The locking claw (3) is rotatably connected to the middle of the traction seat (1).
9. A method for connecting a steel-aluminum hybrid structure semi-trailer, the method being based on the steel-aluminum hybrid structure semi-trailer connecting device according to any one of claims 1 to 8, characterized in that, Includes the following steps: First, the towing seat (1), towing pin (2), and locking claw (3) of the steel-aluminum hybrid structure semi-trailer connecting device are made. Then, the towing seat (1) and towing pin (2) are fixedly installed on the corresponding positions on the semi-trailer. Next, under the drive of the semi-trailer, the towing seat (1) is aligned with the pin part (25) of the towing pin (2). Then, the locking claw (3) is opened, and the concave ring part of the pin part (25) is inserted into the towing seat (1). Finally, the locking claw (3) is locked to realize the connection of the steel-aluminum hybrid structure semi-trailer connecting device.