A preparation method of a thermal insulation plate connecting profile for a lightweight refrigerated vehicle and the thermal insulation plate connecting profile

Abstract

This invention discloses a method for preparing a lightweight magnesium alloy structural profile for refrigerated trucks, belonging to the field of refrigerated truck technology. It also discloses a connecting profile manufactured using this method. The method involves heating a rod and then extruding it through a die to form a connecting profile with a first connecting cavity and a second connecting cavity. A connecting partition between the two cavities serves as the end of an insulation plate, which is inserted and fixed as a load-bearing component. A portion of the connecting partition is then immersed in molten insulation liquid and, after cooling, an insulation layer is formed on the partition surface. This insulation layer interrupts the continuous heat transfer path along the profile on the metal substrate of the connecting partition, creating a thermal break area between the covered and uncovered portions of the connecting partition. This reduces direct heat conduction between the interior of the truck and the exterior environment via the partition. Simultaneously, the low thermal conductivity of the insulation layer reduces the risk of condensation on the surface of the connecting partition.

Description

Technical Field

[0001] This invention relates to the field of refrigerated truck manufacturing technology, specifically to a method for preparing a lightweight refrigerated truck insulation panel connecting profile and the connecting profile itself. Background Technology

[0002] Traditional refrigerated trucks mostly use steel frames, which have problems such as heavy weight, rapid heat conduction, and poor heat insulation performance.

[0003] Chinese utility model patent publication number "CN216761927U" discloses a modular box structure for refrigerated truck compartments, including a wooden base frame, two first extruded edge strips and two second extruded edge strips, and several steel profiles. The wooden base frame includes a first panel, two first side panels and two second side panels. The first extruded edge strips are attached to the angle between the first side panels and the first panel, and the second extruded edge strips are attached to the angle between the second side panels and the first panel. One end of the steel profile is inserted into a groove of one of the two first extruded edge strips, and the other end of the steel profile is inserted into the corresponding groove of the other of the two first extruded edge strips.

[0004] However, the frame of the aforementioned refrigerated truck body using a spliced ​​structure is prone to gaps at the joints. When the refrigerated truck is running, the inside of the compartment is continuously exposed to low-temperature cold air, while the outside remains at ambient temperature, resulting in a significant temperature difference. Due to the presence of these gaps, heat is easily transferred along the steel profiles and joint interfaces, creating a pronounced thermal bridge effect. Thermal bridging not only leads to cold loss and increased refrigeration energy consumption but also causes uneven temperature distribution on the inner and outer surfaces of the side panels, resulting in condensation at the gaps. Over long-term use, this can easily lead to problems such as panel deformation due to moisture, corrosion of metal parts, and aging of the insulation layer, severely impacting the service life and thermal insulation reliability of the truck body. Summary of the Invention

[0005] This invention aims to solve the problems of rapid heat conduction, poor insulation, and weak structural fixation of existing refrigerated truck edge-sealing profiles. It provides a method for preparing connecting profiles that solves thermal breakage, low density, and multiple fixed insulation boards through a semi-dip-plastic process. The connecting profiles prepared by this method improve the insulation capacity of refrigerated truck compartments.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is: a method for preparing lightweight insulation board connecting profiles for refrigerated trucks, characterized by comprising the following steps: S1: Substrate selection and pretreatment: Select a bar as the substrate, heat the substrate and send it into the extrusion die; S2: Extrusion molding, the extrusion die extrudes the substrate to form a first connecting cavity and a second connecting cavity, and a connecting partition is formed between the first connecting cavity and the second connecting cavity, and then cooled and shaped to form a connecting profile; S3: Semi-immersion plastic treatment, controlling the tilt angle and movement distance of the connecting profile, immersing the connecting partition part into the molten heat insulation liquid, and then removing the connecting profile to allow the heat insulation liquid to cool and form a heat insulation layer.

[0007] By adopting the above technical solution: the bar is heated and then extruded into a connecting profile with a first connecting cavity and a second connecting cavity. The connecting partition between the two cavities serves as the end of the insulation board, which is inserted and fixed as a load-bearing part. Then, a part of the connecting partition is immersed in molten insulation liquid and, after being removed and cooled, an insulation layer is formed on the surface of the partition. This insulation layer cuts off the path of continuous heat transfer along the profile on the metal substrate of the connecting partition, so that a thermal break area is formed between the part of the connecting partition covered by the insulation layer and the uncovered part. This reduces the direct heat conduction between the cold air inside the compartment and the outside environment through the partition. At the same time, the low thermal conductivity of the insulation layer reduces the risk of condensation on the surface of the connecting partition. In addition, the unplasticized area of ​​the connecting partition still maintains the original strength and connection rigidity of the metal substrate to fix the end of the insulation board. The plasticized area further reduces the local mass of the profile through the micro-foaming structure of the insulation layer. Thus, while ensuring the structural reliability of the connecting profile, the risk of cold air loss and condensation caused by the thermal bridge effect at the splicing point of the refrigerated compartment is reduced, extending the service life and insulation reliability of the compartment.

[0008] The above-mentioned method for preparing a lightweight refrigerated truck insulation board connecting profile can be further configured as follows: it also includes step S4: hole opening treatment, wherein a plurality of riveting holes for connecting the insulation board are opened along the length direction on the connecting partition.

[0009] By adopting the above technical solution: after the semi-immersion plastic treatment is completed to form the heat insulation layer, several riveting holes for connecting the insulation board are opened along the length direction on the connecting partition. After the end of the insulation board is inserted into the first connecting cavity or the second connecting cavity, it can be mechanically fixed by rivets passing through the riveting holes. The riveting connection method does not rely on adhesive and can be quickly assembled on the car body assembly site. At the same time, the spacing of the riveting holes on the connecting partition allows the insulation board to obtain multi-point uniform constraint along the length direction, so as to reduce the relative displacement between the insulation board and the connecting profile during vehicle operation vibration, thereby avoiding the expansion of gaps or the aggravation of cold bridges caused by loose connections.

[0010] The above-mentioned method for preparing a lightweight refrigerated truck insulation board connecting profile can be further configured as follows: Step S3 includes step S3.1: baking and cooling, placing the connecting profile coated with heat insulation liquid in an oven for a period of time and then taking it out and letting it stand to promote the cooling of the heat insulation liquid to form a heat insulation layer.

[0011] By adopting the above technical solution, the connecting profiles coated with heat insulation liquid are placed in an oven for a period of time and then removed and left to stand. This allows the heat insulation liquid to slowly cool and fully solidify under controlled temperature conditions. Compared with natural cooling, this reduces the micro-cracks or uneven shrinkage inside the heat insulation layer caused by inconsistent cooling rates between the inside and outside. This is beneficial to improving the bonding density and long-term adhesion stability between the heat insulation layer and the substrate of the connecting partition. At the same time, the constant temperature environment during the baking process keeps the heat insulation liquid at a low viscosity during the gelation stage, which is conducive to wetting the micropores on the substrate surface. This enhances the anti-peeling ability of the heat insulation layer under alternating hot and cold conditions, thereby further reducing the risk of thermal bridge effect recurrence at the joint of the refrigerated compartment due to aging or cracking of the heat insulation layer.

[0012] The above-mentioned method for preparing a lightweight refrigerated truck insulation board connecting profile can be further configured as follows: the oven temperature is 200~220℃, and the baking time is 25~35 seconds.

[0013] By adopting the above technical solution, the heat insulation liquid obtains suitable fluidity in the molten state to wet the micropores on the surface of the connecting partition. At the same time, the baking time is preferably 30 seconds, which can avoid the internal pores caused by incomplete melting of the heat insulation liquid or insufficient venting due to too short a time, and also prevent the heat insulation layer from becoming too brittle or the substrate surface from oxidizing due to too long a time. As a result, the cooled heat insulation layer forms a dense and uniform coating on the surface of the connecting partition, which is beneficial to improving the bonding strength between the heat insulation layer and the substrate and the crack resistance of the heat insulation layer in the cold and heat alternating environment, thereby further enhancing the thermal bridging effect and long-term service reliability of the connecting profile.

[0014] The above-mentioned method for preparing a lightweight refrigerated truck insulation board connecting profile can be further configured such that the substrate is preferably a magnesium alloy rod.

[0015] By adopting the above technical solution: the substrate is selected as magnesium alloy rod, with a density of approximately 1.7 g / cm³, which is significantly lower than that of traditional aluminum alloy or steel profiles. Under the premise of meeting the load-bearing capacity of the connecting profile at the end of the insulation board, the linear density of the finished profile is greatly reduced. At the same time, magnesium alloy has high specific strength and good extrusion formability. After heating, it can be formed into a complex cross-section profile with a first connecting cavity and a second connecting cavity through an extrusion die to match the insertion requirements of insulation boards of different thicknesses. The heat insulation layer formed on the surface of the connecting partition after semi-dip coating provides physical coverage and isolation for the magnesium alloy substrate, reducing the direct contact between the humid and cold air inside the compartment and the magnesium alloy surface to reduce the risk of electrochemical corrosion. Moreover, the partial coverage of the heat insulation layer on the connecting partition does not change the overall structural strength of the magnesium alloy substrate. This allows the connecting profile to achieve thermal bridging function in the area covered by the heat insulation layer, while the uncovered area still maintains the original rigid riveting and load-bearing capacity of the magnesium alloy. Thus, while achieving the dual goals of lightweighting of the compartment connection parts and thermal bridging, the structural durability and fixing reliability of the connecting profile under the long-term humid and hot conditions of refrigerated trucks are guaranteed.

[0016] The above-mentioned method for preparing a lightweight refrigerated truck insulation panel connecting profile can be further configured such that: the insulation layer is made of PP, PE or nano-modified polymer material, with a coating thickness of 0.8–1.5 mm.

[0017] By adopting the above technical solution: the insulation layer is made of PP, PE, or nano-modified polymer materials and coated onto the surface of the connecting partition through a semi-dip coating process. The coating thickness is controlled within the range of 0.8~1.5mm. This thickness ensures that the insulation layer completely covers the metal substrate of the connecting partition to form a continuous thermal break barrier, while avoiding the increase in profile cross-sectional dimensions caused by excessive coating, which would affect the insertion and fitting accuracy of the insulation board end with the first and second connecting cavities. At the same time, PP and PE materials themselves have low thermal conductivity and good low-temperature resistance, maintaining stable insulation performance within the long-term operating temperature range of the refrigerated truck compartment. Without cracking or detachment, the nano-modified polymer material introduces nanofillers into the PP or PE matrix to further reduce the thermal conductivity and improve the interfacial bonding strength between the insulation layer and the magnesium alloy matrix. Combined with the low density of the magnesium alloy substrate, the connecting profiles achieve thermal bridging while maintaining lightweight advantages. Furthermore, the partial coating method of semi-dip plastic coating keeps the riveting hole area of ​​the connecting partition exposed to ensure the reliability of the riveting connection and the assembly accuracy of the fasteners. Thus, while ensuring the structural fixation and lightweight requirements of the connecting profiles, the thermal bridging effect and the risk of cold loss at the splicing of the refrigerated compartment are effectively reduced.

[0018] A heat insulation board connecting profile, characterized in that: it includes a profile body, the profile body is provided with a first connecting cavity and a second connecting cavity, a connecting partition is provided between the first connecting cavity and the second connecting cavity, and the connecting partition is covered with a heat insulation layer.

[0019] By adopting the above technical solution: the profile body is provided with a first connecting cavity and a second connecting cavity for the insulation board end to be inserted and fixed. The heat insulation layer covering the surface of the connecting partition forms a physical isolation between the metal substrate and the external environment, cutting off the path of continuous heat transfer along the profile, thereby forming a thermal bridge in the area of ​​the connecting partition covered by the heat insulation layer. This reduces the direct conduction of cold air inside the compartment to the external environment through the partition. At the same time, the low thermal conductivity of the heat insulation layer reduces the risk of condensation on the surface of the partition under the action of internal and external temperature differences. Moreover, the connecting partition still maintains the original rigidity of the metal substrate after being covered with the heat insulation layer to ensure the reliability of the riveting or fastener connection. Thus, while ensuring the stable connection between the insulation board and the profile, the thermal bridge effect and cold air loss at the splicing point of the refrigerated compartment are effectively reduced, improving the heat insulation reliability and service life of the compartment.

[0020] The aforementioned insulation board connecting profile can be further configured such that the connecting partition includes a first connecting part and a second connecting part, wherein the first connecting part and the second connecting part are provided with a plurality of riveting holes.

[0021] By adopting the above technical solution: the first connecting part and the second connecting part are located on both sides of the connecting partition near the first connecting cavity and the second connecting cavity, respectively. After the end of the insulation board is inserted into the connecting cavity through several through-holes, it can be mechanically fixed by rivets passing through the corresponding holes. The spacing of the rivet holes on the connecting partition allows the insulation board to obtain multi-point uniform constraint along the length direction, reducing the relative displacement between the insulation board and the profile during vehicle operation vibration. At the same time, the rivet holes are opened on the connecting partition after the heat insulation layer is covered. When the rivet passes through, it still maintains contact with the substrate at the opening formed by the heat insulation layer, avoiding the loosening of fasteners or insufficient connection strength caused by the complete coverage of the heat insulation layer. With the insertion and positioning of the end of the insulation board by the first connecting cavity and the second connecting cavity, and the blocking of the heat conduction path by the heat insulation layer of the connecting partition, the connecting profile maintains the thermal break effect and cold loss suppression ability at the splicing of the refrigerated compartment while ensuring connection stability and assembly convenience.

[0022] The above-mentioned insulation board connecting profile can be further configured such that: the connecting profile is also provided with a protective plate, and a heat insulation cavity is formed between the protective plate and the connecting partition.

[0023] By adopting the above technical solution: the profile body is also provided with a protective plate, and a heat insulation cavity is formed between the protective plate and the connecting partition. The air layer in the heat insulation cavity further blocks the heat transfer path between the two sides of the connecting partition due to its low thermal conductivity. Together with the heat insulation layer on the surface of the connecting partition, it forms a multi-layer thermal break structure. At the same time, the protective plate provides physical protection for the heat insulation layer during the use of the car body to reduce the scratching or peeling of the heat insulation layer by external forces during installation or transportation. Moreover, the existence of the heat insulation cavity increases the internal cavity volume of the connecting profile while keeping the cross-sectional dimensions unchanged, thereby further reducing the overall density of the profile. With the insertion and fixing of the insulation board end by the first connecting cavity and the second connecting cavity, and the mechanical locking of the insulation board by the riveting holes, the connecting profile significantly reduces the thermal bridge effect and cold loss at the splicing of the refrigerated car body while ensuring lightweight and structural strength, further improving the heat insulation reliability and service life of the car body.

[0024] The beneficial effects of this invention are as follows: First, using magnesium alloy rods as the base material, a cross-sectional structure with a first connecting cavity and a second connecting cavity is obtained through extrusion molding, so that the connecting partition between the two cavities forms the insertion and fixing part at the end of the insulation board. Then, a heat insulation layer is coated on the local surface of the connecting partition through a semi-dip plastic coating process, cutting off the continuous heat transfer path on the metal substrate to form a thermal break area, thereby effectively reducing the loss of cold air from the compartment through the splice and reducing the risk of condensation on the partition surface. Combined with the low density characteristics of magnesium alloy, the profile achieves significant weight reduction while maintaining load-bearing rigidity. At the same time, the micro-foamed structure of the heat insulation layer further reduces the local mass, thereby improving the heat insulation efficiency and service life of the refrigerated compartment while ensuring connection reliability.

[0025] Secondly, several riveting holes are opened along the length of the connecting partition, so that the end of the insulation board can be quickly and mechanically fixed by rivets after being inserted into the connecting cavity. The multiple evenly distributed rivet holes effectively reduce the relative displacement during operation vibration to maintain connection stability. At the same time, the profile body is provided with a protective plate and forms a thermal insulation cavity with the connecting partition. This air layer and the thermal insulation layer work together to form a multi-layer thermal break structure. The protective plate provides physical protection for the thermal insulation layer during installation and transportation to reduce the risk of scratches or peeling. Thus, while taking into account lightweight, assembly efficiency and riveting strength, the thermal insulation reliability and long-term durability of the refrigerated compartment splice are significantly improved.

[0026] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the preparation method of the present invention; Figure 2 This is a schematic diagram of the insulation board connection profile structure according to Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the insulation board connection profile structure according to Embodiment 2 of the present invention; Label annotations: connecting profile 1, profile body 11, first connecting cavity 12, second connecting cavity 13, connecting partition 14, first connecting part 141, second connecting part 142, heat insulation layer 15, protective plate 16, heat insulation cavity 17. Detailed Implementation

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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.

[0029] This application provides a method for preparing lightweight insulation panel connecting profiles for refrigerated trucks, such as... Figure 1 As shown, it includes the following steps: S1: Substrate selection and pretreatment: Select a bar as the substrate, heat the substrate and send it into the extrusion die; S2: Extrusion molding, the extrusion die extrudes the substrate to form a first connecting cavity 12 and a second connecting cavity 13, and a connecting partition 14 is formed between the first connecting cavity 12 and the second connecting cavity 13, and then cooled and shaped to form a connecting profile; S3: Semi-immersion plastic treatment, control the tilt angle and moving distance of the connecting profile, immerse part of the connecting partition 14 into the molten heat insulation liquid, and then take out the connecting profile to promote the cooling of the heat insulation liquid to form the heat insulation layer 15; S3.1: Baking and cooling: Place the connecting profile coated with heat insulation liquid in an oven at 210°C and bake for 30 seconds, then remove and let stand to allow the heat insulation liquid to cool and form the heat insulation layer 15. S4: Opening treatment, several riveting holes for connecting insulation boards are opened along the length direction on the connecting partition 14.

[0030] This application also provides a thermal insulation board connecting profile manufactured using the above-described preparation method, such as... Figure 2 , Figure 3 As shown, it includes a profile body 11, the profile body 11 is provided with a first connecting cavity 12 and a second connecting cavity 13, a connecting partition 14 is provided between the first connecting cavity 12 and the second connecting cavity 13, and the connecting partition 14 is covered with a heat insulation layer 15.

[0031] The connecting partition 14 includes a first connecting part 141 and a second connecting part 142, and the first connecting part 141 and the second connecting part 142 are provided with a plurality of riveting holes.

[0032] In the following embodiments, the substrate is selected from AZ40M magnesium alloy rods according to the GB / T 5156-2022 standard.

[0033] Simultaneously, thermal insulation performance tests, temperature field and airflow organization tests were conducted.

[0034] The thermal insulation performance test is conducted in accordance with GB 29753-2023, simulating extreme temperatures (such as -20℃ to 40℃) in an environmental chamber and using an internal heating method.

[0035] Temperature field and airflow organization tests were conducted in accordance with the principles of GB 29753-2023 and QC / T 449-2010, under vehicle no-load or simulated load conditions.

[0036] Example 1: A method for preparing a lightweight insulation panel connecting profile for a refrigerated truck, comprising the following steps: S1: Substrate Selection and Pretreatment Select a magnesium alloy rod as the base material, heat the base material and send it into the extrusion die; S2: Extrusion molding The extrusion die extrudes the substrate to form a first connecting cavity 12 and a second connecting cavity 13, and a connecting partition 14 is formed between the first connecting cavity 12 and the second connecting cavity 13. Then, it is cooled and shaped to form a connecting profile. S3: Semi-dip coating treatment A portion of the connecting partition 14 is immersed in molten PE liquid, so that the molten PE liquid covers the connecting partition 14. After the molten PE liquid cools, a heat insulation layer 15 is formed on the outer surface of the connecting partition 14.

[0037] S3.1: Baking and Cooling The connecting profile coated with heat insulation liquid is placed in an oven at 210°C and baked for 30 seconds. After that, it is taken out and left to stand, so that the PE melt cools down to form the heat insulation layer 15. S4: Hole opening treatment Several riveting holes for connecting insulation boards are provided along the length of the connecting partition 14.

[0038] An insulation board connecting profile includes a profile body 11 extruded from a magnesium alloy rod. The profile body 11 is provided with a first connecting cavity 12 and a second connecting cavity 13. A connecting partition 14 is provided between the first connecting cavity 12 and the second connecting cavity 13. The outer surface of the connecting partition 14 is covered with a PE heat insulation layer 15. The connecting partition 14 includes a first connecting part 141 and a second connecting part 142. The first connecting part 141 and the second connecting part 142 are provided with a plurality of riveting holes.

[0039] Example 2: A method for preparing a lightweight insulation panel connecting profile for a refrigerated truck, comprising the following steps: S1: Substrate Selection and Pretreatment Select a magnesium alloy rod as the base material, heat the base material and send it into the extrusion die; S2: Extrusion molding The substrate is extruded by an extrusion die to form a first connecting cavity 12 and a second connecting cavity 13, and a connecting partition 14 is formed between the first connecting cavity 12 and the second connecting cavity 13. At the same time, a protective plate 16 is formed between the first connecting cavity 12 and the second connecting cavity 13. The protective plate 16 and the sidewalls of the first connecting cavity 12 and the second connecting cavity 13 form a heat insulation cavity 17. The substrate is then cooled and shaped to form a connecting profile. S3: Semi-dip coating treatment A portion of the connecting partition 14 is immersed in the molten PP liquid, so that the molten PP liquid covers the connecting partition 14. After the molten PP liquid cools, a heat insulation layer 15 is formed on the outer surface of the connecting partition 14. S3.1: Baking and Cooling The connecting profile coated with heat insulation liquid is placed in an oven at 210℃ and baked for 30 seconds, then removed and left to stand to allow the PP melt to cool and form a heat insulation layer 15. S4: Hole opening treatment Several riveting holes for connecting insulation boards are provided along the length of the connecting partition 14.

[0040] An insulation board connecting profile includes a profile body 11 extruded from a magnesium alloy rod. The profile body 11 is provided with a first connecting cavity 12 and a second connecting cavity 13. A connecting partition 14 is provided between the first connecting cavity 12 and the second connecting cavity 13. The outer surface of the connecting partition 14 is covered with a PP heat insulation layer 15. The connecting partition 14 includes a first connecting part 141 and a second connecting part 142. The first connecting part 141 and the second connecting part 142 are provided with a plurality of riveting holes.

[0041] Example 3: A method for preparing a lightweight insulation panel connecting profile for a refrigerated truck, comprising the following steps: S1: Substrate Selection and Pretreatment Select a magnesium alloy rod as the base material, heat the base material and send it into the extrusion die; S2: Extrusion molding The substrate is extruded by an extrusion die to form a first connecting cavity 12 and a second connecting cavity 13, and a connecting partition 14 is formed between the first connecting cavity 12 and the second connecting cavity 13. At the same time, a protective plate 16 is formed between the first connecting cavity 12 and the second connecting cavity 13. The protective plate 16 and the sidewalls of the first connecting cavity 12 and the second connecting cavity 13 form a heat insulation cavity 17. The substrate is then cooled and shaped to form a connecting profile. S3: Semi-dip coating treatment A portion of the connecting partition 14 is immersed in the molten modified polymer liquid, so that the molten modified polymer liquid covers the connecting partition 14. After the molten modified polymer liquid cools, a heat insulation layer 15 is formed on the outer surface of the connecting partition 14. S3.1: Baking and Cooling The connecting profile coated with heat insulation liquid is placed in an oven at 210°C and baked for 30 seconds. After that, it is taken out and left to stand, so that the modified polymer heat insulation liquid cools down to form a heat insulation layer 15. S4: Hole opening treatment Several riveting holes for connecting insulation boards are provided along the length of the connecting partition 14.

[0042] An insulation board connecting profile includes a profile body 11 extruded from a magnesium alloy rod. The profile body 11 is provided with a first connecting cavity 12 and a second connecting cavity 13. A connecting partition 14 is provided between the first connecting cavity 12 and the second connecting cavity 13. The outer surface of the connecting partition 14 is covered with a modified polymer heat insulation layer 15. The connecting partition 14 includes a first connecting part 141 and a second connecting part 142. The first connecting part 141 and the second connecting part 142 are provided with a plurality of riveting holes.

[0043] Comparative Example 1: A method for preparing a thermal insulation board connecting profile includes the following steps: S1: Substrate Selection 6061-T6 aluminum alloy bars were selected as the base material, and the base material was heated and then fed into the extrusion die. S2: Extrusion molding The extrusion die extrudes the substrate, forming a first connecting cavity 12 and a second connecting cavity 13, and a connecting partition 14 is formed between the first connecting cavity 12 and the second connecting cavity 13; S3: Hole opening treatment Several riveting holes for connecting insulation boards are provided along the length of the connecting partition 14.

[0044] The insulation board connecting profile prepared by the above preparation method is made of conventional 6061-T6 aluminum alloy profile for refrigerated trucks. The profile body 11 includes a first connecting cavity 12 and a second connecting cavity 13. A connecting partition 14 is provided between the first connecting cavity 12 and the second connecting cavity 13. The connecting partition 14 extends to both sides to form a first connecting part 141 and a second connecting part 142. A plurality of riveting holes for riveting the insulation board are opened on the first connecting part 141 and the second connecting part 142 along the length direction.

[0045] Comparative Example 2: A method for preparing a thermal insulation board connecting profile includes the following steps: S1: Substrate Selection Q235 carbon structural steel was selected as the base material, and the base material was heated and then sent into the extrusion die. S2: Extrusion molding The extrusion die extrudes the substrate, forming a first connecting cavity 12 and a second connecting cavity 13, and a connecting partition 14 is formed between the first connecting cavity 12 and the second connecting cavity 13; S3: Hole opening treatment Several riveting holes for connecting insulation boards are provided along the length of the connecting partition 14.

[0046] The insulation board connecting profile prepared by the above preparation method is made of conventional Q235 carbon structural steel profile for refrigerated trucks. The profile body 11 includes a first connecting cavity 12 and a second connecting cavity 13. A connecting partition 14 is provided between the first connecting cavity 12 and the second connecting cavity 13. The connecting partition 14 extends to both sides to form a first connecting part 141 and a second connecting part 142. A plurality of riveting holes for riveting the insulation board are opened on the first connecting part 141 and the second connecting part 142 along the length direction.

[0047] After applying sealant to the first connecting cavity 12 and the second connecting cavity 13 of the connecting profiles in the above embodiments and comparative embodiments, the insulation board is inserted into the first connecting cavity 12 and the second connecting cavity 13 to assemble the refrigerated truck compartment of the corresponding embodiments and comparative embodiments. The refrigerated truck compartment is then subjected to insulation and heat insulation performance tests, as well as temperature field and airflow organization tests. 1. Thermal insulation and heat insulation performance test The test was conducted according to GB 29753-2023, "Safety Requirements and Test Methods for Refrigerated Vehicles Transporting Perishable Foods and Biological Products by Road". The internal heating method was used, and the test procedure was as follows: The refrigerated truck compartment was placed empty in the environmental chamber, and the temperature of the environmental chamber was set to -20℃ (simulating a low temperature environment) and 40℃ (simulating a high temperature environment). The air velocity at a distance of 10cm from the outside of the carriage is maintained at 1m / s to 2m / s. Temperature sensors (no fewer than 9 measuring points, distributed at the front, middle, rear, and upper, middle, and lower positions) are installed inside the carriage, and temperature sensors (no fewer than 6 measuring points, distributed on each side wall and top) are installed on the outside. Start the internal heating device and wait for the average temperature inside the carriage to stabilize to the set value (20℃ under -20℃ conditions and 0℃ under 40℃ conditions) and then continue to measure for no less than 6 hours. Record the total heat power W and the temperature difference Δθ between the inside and outside of the chamber during the measurement period, and calculate the total heat transfer coefficient K according to the formula.

[0048] 2. Temperature field and airflow organization test The test was conducted in accordance with the principles of GB 29753-2023 and QC / T 449-2010 "Technical Conditions and Test Methods for Insulated and Refrigerated Trucks". Test procedures: The test was conducted with the refrigerated truck compartment either empty or under simulated load conditions (with heat load simulation materials evenly placed at 50% of the rated load). The ambient temperature is set at 35℃±2℃, and the refrigeration unit inside the carriage is set at -18℃. Temperature sensors (no fewer than 16 measuring points) are evenly distributed throughout the interior of the carriage. The refrigeration unit is run continuously for 8 hours, and the temperature of each measuring point is recorded every 30 minutes. Analyze the temperature field distribution and temperature uniformity inside the carriage, and calculate the maximum temperature difference and the average temperature difference.

[0049] Table 1. Test results of Examples 1-3 and Control Examples 1-2 Overall heat transfer coefficient K (W / m²·℃) — Operating conditions with an ambient temperature of -20℃ 0.38 0.33 0.31 0.52 0.61 — Operating condition with an ambient temperature of 40℃ 0.40 0.35 0.33 0.55 0.64 Thermal conductivity of insulation layer (W / m·K) ≤0.040 0.21～0.26 0.15～0.20 Thermal conductivity of profile substrate (W / m·K) 54 54 54 167 54 Compared with the connecting profile of the control embodiment, the insulation board connecting profiles of the above embodiments have the following advantages: 1. Significantly lightweight: The connecting profile adopts magnesium alloy + semi-dip plastic coating process, with a unit volume density of ≤1.7 g / cm³, which can reduce the weight by more than 30% compared with traditional steel; 2. High efficiency with thermal break: The connecting partition of the connecting profile is partially dipped in plastic for localized thermal insulation, which effectively blocks the conduction of cold and heat and improves the thermal insulation performance of the refrigerated truck compartment; 3. Securely fixed: The connecting profiles can be connected to the insulation board through a triple fixing mechanism (glue + glue + rivets), thus taking into account both adhesive bonding and mechanical locking, and has strong vibration and impact resistance. 4. Convenient assembly: By extruding the first and second connecting cavities into the connecting profiles, the insulation board can be inserted into the first and second connecting cavities during the assembly of the refrigerated truck compartment, thus realizing modular step-by-step assembly, reducing human error, and shortening the production cycle.

[0050] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a lightweight insulation panel connecting profile for a refrigerated truck, characterized in that: It includes the following steps: S1: Substrate selection and pretreatment: Select a bar as the substrate, heat the substrate and send it into the extrusion die; S2: Extrusion molding, the extrusion die extrudes the substrate to form a first connecting cavity and a second connecting cavity, and a connecting partition is formed between the first connecting cavity and the second connecting cavity, and then cooled and shaped to form a connecting profile; S3: Semi-immersion plastic treatment, controlling the tilt angle and movement distance of the connecting profile, immersing the connecting partition part into the molten heat insulation liquid, and then removing the connecting profile to allow the heat insulation liquid to cool and form a heat insulation layer.

2. The method for preparing a lightweight refrigerated truck insulation panel connecting profile according to claim 1, characterized in that: It also includes step S4: opening treatment, where a number of riveting holes for connecting insulation boards are opened along the length direction on the connecting partition.

3. The method for preparing a lightweight refrigerated truck insulation panel connecting profile according to claim 1, characterized in that: Step S3 includes step S3.1: baking and cooling, in which the connecting profile coated with heat insulation liquid is placed in an oven for baking and then taken out and left to stand, so that the heat insulation liquid cools down to form a heat insulation layer.

4. The method for preparing a lightweight refrigerated truck insulation panel connecting profile according to claim 3, characterized in that: The oven temperature is 200~220℃, and the baking time is 25~35 seconds.

5. The method for preparing a lightweight refrigerated truck insulation panel connecting profile according to claim 1, characterized in that: The substrate is preferably a magnesium alloy rod.

6. The method for preparing a lightweight refrigerated truck insulation panel connecting profile according to claim 1, characterized in that: The insulation layer is made of PP, PE or nano-modified polymer materials, with a coating thickness of 0.8–1.5 mm.

7. An insulation board connecting profile manufactured using the method for preparing lightweight refrigerated truck insulation board connecting profiles according to any one of claims 1 to 6, characterized in that: The material includes a profile body, which has a first connecting cavity and a second connecting cavity, and a connecting partition is provided between the first connecting cavity and the second connecting cavity. The connecting partition is covered with a heat insulation layer.

8. The insulation board connecting profile according to claim 7, characterized in that: The connecting partition includes a first connecting part and a second connecting part, and the first connecting part and the second connecting part are provided with a plurality of riveting holes.

9. The insulation board connecting profile according to claim 8, characterized in that: The connecting profile is also provided with a protective plate, and a temperature insulation cavity is formed between the protective plate and the connecting partition.

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