A double-layer sound-absorbing and sealing block with sound insulation and its preparation and application method

Abstract

This invention discloses a double-layer partition sound-absorbing and sealing block, comprising a sealing block body that fills a vehicle body cavity. The sealing block body includes a sound-insulating sealing block, a sound-absorbing sealing block, and a connecting plate. The sound-insulating sealing block is connected to one side of the connecting plate, and the sound-absorbing sealing block is connected to the other side. The sound-insulating and sound-absorbing sealing blocks are arranged opposite each other on the connecting plate to form a double-layer sealing block. The connecting plate is provided with mounting clips, and the sealing block body is installed in the vehicle body cavity via these clips. After foaming, the double-layer partition sound-absorbing and sealing block of this invention can tightly bond the bracket body to the inner body sheet metal, sealing the entire cross-sectional cavity. This effectively blocks the cavity channel, improving sound insulation, vibration reduction, and noise reduction in the car cabin, thus enhancing the vehicle's NVH performance.

Description

Technical Field

[0001] This invention belongs to the field of automotive cavity sound insulation technology, specifically relating to a double-layer partition sound-absorbing and sealing block and its preparation and application methods. Background Technology

[0002] Modern car body side panels are generally designed with a cavity structure. During driving, high-speed airflow can easily enter the cavity and form vortices within it, generating turbulent airflow noise and causing resonance of the sheet metal parts, resulting in resonance noise that affects driving comfort. At the same time, moisture and dirt can easily enter the cavity, causing corrosive damage to the vehicle body. Therefore, the cavity needs to be sealed and acoustically isolated.

[0003] Sealing blocks are widely used in the automotive industry as a cavity-filling and sealing technology. They are used to block cavities, reduce noise, and prevent moisture ingress, thereby improving passenger comfort. Sealing block designs vary, generally including a bracket and pre-formed thermo-expanding sealant. The center of the sealing block is a high-temperature resistant plastic molded bracket, surrounded by pre-formed thermo-expanding sealant. The shape of the sealing block can be designed according to the cross-sectional dimensions of the cavity at the installation location. After the sealant expands in the painting oven, it bonds the bracket and the cavity wall, thus sealing the entire cavity. These sealing blocks typically have one or two mounting clips for direct attachment to the vehicle body panels. Their design and installation process is simple, requiring precise positioning on the vehicle body through mounting holes. They offer excellent sound insulation and are easy to install, making them an indispensable component in automotive manufacturing.

[0004] However, current sealing blocks are generally single-layer structures, primarily for sound insulation. They come in various designs, but due to cost considerations, foamed sound insulation materials are rarely used. Instead, they employ racetrack-style or sandwich structures, resulting in relatively poor sound insulation performance.

[0005] A utility model patent with application number CN201220445306, published on March 27, 2013, provides a sealing block for vehicle noise reduction. The sealing block uses a porous nylon resin as a skeleton and is composited with an ethylene-methyl acrylate copolymer foam material. The sealing block is square and has several stepped grooves. At least one corner of the sealing block has a semi-circular mounting hole, and one end of the sealing block is fitted with a plastic clip. However, this patent still fails to solve the aforementioned technical problems. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a double-layer partition sound-absorbing and sealing block that is simple in structure, easy to use, and capable of blocking and absorbing cavity noise. After foaming, the double-layer partition sound-absorbing and sealing block of the present invention can tightly bond the bracket body to the inner body sheet metal, sealing the entire cross-sectional cavity. This effectively blocks the cavity channel, achieving complete sealing and preventing noise from entering through gaps in the body, thereby further improving and enhancing sound insulation, vibration reduction, and noise reduction in the car cabin, thus improving the NVH performance of the vehicle. The present invention also discloses a method for preparing and using the double-layer partition sound-absorbing and sealing block.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows: a double-layer partition sound-absorbing and sealing block, comprising a sealing block body, the sealing block body filling a vehicle body cavity, the sealing block body comprising a sound-insulating sealing block, a sound-absorbing sealing block, and a sealing block connecting plate, the sound-insulating sealing block being connected to one side of the sealing block connecting plate, the sound-insulating sealing block being connected to the other side of the sealing block connecting plate, the sound-insulating sealing block and the sound-absorbing sealing block being disposed opposite to each other on the sealing block connecting plate to form a double-layer sealing block, the sealing block connecting plate being provided with mounting buckles, and the sealing block body being installed in the vehicle body cavity through the mounting buckles on the sealing block connecting plate.

[0008] Furthermore, the sound insulation sealant block includes a central partition, an expanding sealant, and a fixing post. The expanding sealant is fixedly connected to the central partition via the fixing post, and the expanding sealant is evenly adhered to the outer surface of the central partition.

[0009] Furthermore, the sound-absorbing sealant block includes a central partition, an expanding sealant, and a fixing post. The expanding sealant is fixedly connected to the central partition via the fixing post, and the expanding sealant is evenly adhered to the outer surface of the central partition.

[0010] Furthermore, the sound-absorbing sealing block also includes a sound-absorbing sealing block latch, which is disposed on the inner side of the central partition of the sound-absorbing sealing block. The sound-absorbing sealing block latch is inserted into the latch fixing cavity and engaged with the sound-absorbing sealing block latch.

[0011] Furthermore, both the sound insulation sealing block and the sound absorption sealing block are made of thermoplastic material. The sound insulation sealing block and the sound absorption sealing block have the same shape. The shape of the sound insulation sealing block and the sound absorption sealing block corresponds to the cross-sectional shape of the vehicle body cavity, but is smaller than the shape of the vehicle body cavity. A gap of 3mm to 5mm is provided between the sound insulation sealing block and the sound absorption sealing block and the cavity wall of the vehicle body cavity.

[0012] Furthermore, the central partition of the sound insulation sealant block and the central partition of the sound absorption sealant block are connected together by a sealant block connecting plate and are injection molded together by an injection molding process. The thickness of the central partition of the sound insulation sealant block and the central partition of the sound absorption sealant block are both 1mm to 3mm; the thickness of the expansion sealant of the sound insulation sealant block and the expansion sealant of the sound absorption sealant block are both 2mm to 4mm.

[0013] Furthermore, the side of the sealing block connecting plate opposite to the sound-insulating and sound-absorbing sealing blocks is provided with sealing block mounting clips I and II. The sealing block body is fixedly mounted on the sheet metal of the vehicle body cavity via sealing block mounting clips I and II. The sheet metal of the vehicle body cavity is provided with mounting holes I and II for cooperating with sealing block mounting clips I and II. The sealing block mounting clips I and II are of different sizes, as are mounting holes I and II.

[0014] The present invention also provides a method for preparing a double-layer partition sound-absorbing and sealing block. Based on the above-mentioned double-layer partition sound-absorbing and sealing block, the preparation method includes the following steps:

[0015] Step 1. Inject thermoplastic material into the injection mold to form an integrated bracket body consisting of a central partition for sound insulation and sealing blocks, a central partition for sound absorption and sealing blocks, a connecting plate for sealing blocks, mounting clips for sealing blocks, and locking clips for sealing blocks.

[0016] Step 2. In the second injection mold, the sound-insulating expanding sealant and the sound-absorbing sound-insulating expanding sealant are respectively injected into the central partition of the sound-insulating sealant block and the central partition of the sound-absorbing sealant block, and then demolded to form a sealant block.

[0017] Step 3. The connection thickness between the sealing block connecting plate and the central partition of the sealing block is less than the thickness of the sealing block connecting plate and the central partition of the sealing block; the sealing block connecting plate is provided with mounting buckle process holes I and II for installing the sealing block mounting buckle I and the sealing block mounting buckle II.

[0018] Step 4. Bend the central partition of the sound insulation sealant block and the central partition of the sound absorption sealant block. After the central partition of the sound insulation sealant block and the central partition of the sound absorption sealant block are locked together with the sound insulation sealant block lock and the lock baffle, a double-layer expansion sealant block is formed.

[0019] Step 5. The distance between the central partition of the sound insulation sealant block and the central partition of the sound absorption sealant block is 30mm to 50mm.

[0020] This invention also provides a method for using a double-layer partition sound-absorbing and sealing block, characterized in that: based on the above-mentioned double-layer partition sound-absorbing and sealing block, the method of use includes:

[0021] a. Insert the sealant block mounting clips I and II into the sealant block mounting holes on the sill reinforcement plate along the vertical sheet metal, and weld the sill reinforcement plate with the sealant block to the inner sill plate to form a sill cavity;

[0022] b. After the car body is welded, the heat-expandable sealant is thermally reacted in the electrophoretic oven. The heat-expandable sealant expands in the horizontal and vertical directions and adheres firmly and reliably to the inner wall of the door sill cavity sheet metal.

[0023] c. The cavities on the car body are filled with sealing blocks using operations a and b. All cavities on the car body are completely sealed, bonding the bracket body and sheet metal wall together, thus sealing the entire cavity and firmly and reliably adhering to the inner wall of the cavity. After cooling and solidification, it becomes an integral structure with the cavity.

[0024] The advantages of using the technical solution of this invention are:

[0025] 1. The double-layer partition sound-absorbing and sealing block of the present invention can tightly bond the bracket body and the inner body sheet metal into one piece after foaming, sealing the entire cross-sectional cavity, effectively blocking the cavity channel at that location, achieving full sealing, and preventing noise from entering through the gaps in the body, thereby further improving and enhancing the sound insulation, vibration reduction, and noise reduction in the car cabin, and improving the NVH performance of the car.

[0026] 2. When a car is traveling at high speed, the noise generated in the side cavity is eliminated by each central baffle, which eliminates most of the sound transmitted from the previous baffle. After the two noise reductions by the baffles, the noise gradually weakens, thus playing a double-layer sound insulation role and effectively improving the NVH performance of the whole vehicle. Attached Figure Description

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0028] Figure 1This is a schematic diagram of the three-dimensional structure of the sealing block in this invention;

[0029] Figure 2 This is a top view of the sealing block in this invention;

[0030] Figure 3 This is a front view of the sealant block in this invention;

[0031] Figures 4(a) and 4(b) are three-dimensional structural schematic diagrams of an embodiment of the sealing block locking device in this invention;

[0032] Figures 5(a) and 5(b) are the top view and front view of the sealing block before folding in this invention, respectively.

[0033] Figures 6(a), 6(b), 6(c), 6(d), and 6(e) are schematic diagrams of the structure of the sealing block after assembly in the vehicle body cavity in this invention.

[0034] The markings in the above figures are as follows: 10-Sealing block body; 1-Sound insulation sealing block; 11-Sound insulation sealing block central partition; 12-Sound insulation sealing block expansion sealant; 13-Sound insulation sealing block fixing post; 14-Lock baffle; 15-Snap-on fixing cavity; 16-Sound insulation sealing block lock; 2-Sound absorption sealing block; 21-Sound insulation sealing block central partition; 22-Sound absorption sealing block expansion sealant; 23-Sound absorption sealing block fixing post; 24-Sound absorption sealing block lock; 3-Sealing block connecting plate; 31-Sealing block mounting clip I; 32-Sealing block mounting clip II; 33-Mounting hole expansion sealant; 34-Mounting clip process hole I; 35-Mounting clip process hole II; 20-Sill reinforcement plate; 30-Sill inner plate; 40-Sill cavity. Detailed Implementation

[0035] In this invention, it should be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "planar direction," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the invention.

[0036] like Figure 1As shown, a double-layer sound-absorbing and sound-insulating sealing block includes a sealing block body 10, which fills a vehicle body cavity. The sealing block body 10 includes a sound-insulating sealing block 1, a sound-absorbing sealing block 2, and a sealing block connecting plate 3. The sound-insulating sealing block 1 is connected to one side of the sealing block connecting plate 3, and the sound-insulating sealing block 1 is connected to the other side of the sealing block connecting plate 3. The sound-insulating sealing block 1 and the sound-absorbing sealing block 2 are arranged opposite to each other on the sealing block connecting plate 3 to form a double-layer sealing block. The sealing block connecting plate 3 is provided with mounting buckles, and the sealing block body 10 is installed in the vehicle body cavity through the mounting buckles on the sealing block connecting plate 3. The double-layer partition sound-absorbing and sealing block of the present invention can be tightly bonded to the bracket body and the inner body sheet metal after foaming, sealing the entire cross-sectional cavity, effectively blocking the cavity channel, achieving full sealing, and preventing noise from entering through the gaps in the body, thereby further improving the sound insulation, vibration reduction, and noise reduction in the car cabin, and improving the NVH performance of the car.

[0037] The sound insulation sealant block 1 includes a central partition 11, an expanding sealant 12, and a fixing post 13. The expanding sealant 12 is fixedly connected to the central partition 11 via the fixing post 13. The expanding sealant 12 is evenly attached to the outer surface of the central partition 11.

[0038] The sound insulation sealing block 1 also includes a locking baffle 14 and a sound insulation sealing block lock 16. The locking baffle 14 and the sound insulation sealing block lock 16 are disposed on the inner side of the central partition 11 of the sound insulation sealing block, and a snap-fit ​​fixing cavity 15 is formed between the locking baffle 14 and the sound insulation sealing block lock 16.

[0039] The sound-absorbing sealant block 2 includes a central partition 21, an expanding sealant 22, and a fixing post 23. The expanding sealant 22 is fixedly connected to the central partition 21 via the fixing post 23. The expanding sealant 22 is evenly attached to the outer side of the central partition 21.

[0040] The sound-absorbing sealing block 2 also includes a sound-absorbing sealing block latch 24, which is located on the inner side of the central partition 21 of the sound-absorbing sealing block. The sound-absorbing sealing block latch 24 is inserted into the latch fixing cavity 15 and engaged with the sound-insulating sealing block latch 16.

[0041] Both the sound insulation sealing block 1 and the sound absorption sealing block 2 are made of thermoplastic material. The sound insulation sealing block 1 and the sound absorption sealing block 2 have the same shape. The shape of the sound insulation sealing block 1 and the sound absorption sealing block 2 corresponds to the cross-sectional shape of the vehicle body cavity, but is smaller than the shape of the vehicle body cavity. There is a gap of 3mm to 5mm between the sound insulation sealing block 1 and the sound absorption sealing block 2 and the cavity wall of the vehicle body cavity.

[0042] The sound insulation and sealing block central partition 11 and the sound absorption and sealing block central partition 21 are connected together by the sealing block connecting plate 3 and are injection molded together by injection molding process. The thickness of the sound insulation and sealing block central partition 11 and the sound absorption and sealing block central partition 21 is 1mm to 3mm.

[0043] Specifically, the outer edges of the central partition 11 of the sound insulation sealant block and the central partition 21 of the sound absorption sealant block maintain a certain gap from the cavity wall. For expanding sealant, the gap is generally set at 3mm to 5mm to ensure that degreasing agents, phosphating agents, and electrophoretic materials used in the automotive manufacturing process can pass smoothly through the cavity of the car body, and to ensure that the inner wall of the sheet metal cavity can be fully wetted. To ensure sound insulation effect, the thickness of the central partition 11 of the sound insulation sealant block and the central partition 21 of the sound absorption sealant block is generally designed to be 1mm to 3mm, preferably 2mm.

[0044] The central partition 11 of the sound-insulating sealant block and the central partition 21 of the sound-absorbing sealant block are connected together by the sealant block connecting plate 3 and are injection molded together. On the side of the sealant block connecting plate 3 opposite to the sound-insulating sealant block 1 and the sound-absorbing sealant block 2, there are sealant block mounting clips I 31 and II 32. The sealant block body 10 is fixedly installed on the sheet metal of the vehicle body cavity using the sealant block mounting clips I 31 and II 32. The sheet metal of the vehicle body cavity has mounting holes I and II for engaging with the sealant block mounting clips I 31 and II 32. The sealant block mounting clips I 31 and II 32 are of different sizes, as are the mounting holes I and II. This is to prevent incorrect installation during the process and to prevent the sealant block body from rotating and misaligning during the rinsing process of the coating tank liquid, which could lead to seal failure.

[0045] To ensure a tight seal throughout the cavity, the sealing block connecting plate 3 has mounting holes for expanding sealant 33. The sealant can be either sound-insulating or sound-absorbing. The connection thickness between the sealing block connecting plate 3 and the central partition is less than the rear section of the partition and connecting plate, facilitating bending and locking of the central partition. The sealing block connecting plate is equipped with mounting buckle process holes I 34 and II 35, simplifying the production of mounting buckles and reducing the complexity of the injection mold.

[0046] To ensure a good seal, the thickness of both the sound-insulating sealant block (expanded sealant 12) and the sound-absorbing sealant block (expanded sealant 22) is 2mm to 4mm. After verification testing and considering manufacturing costs, a thickness of 3mm is preferred to achieve effective sealing and NVH performance. Expanded sealant is a thermally expanding material, comprising a polymer-based adhesive and a foaming agent. Depending on the type of polymer, the function of the expanded sealant can be adjusted. After foaming, the material can be classified as closed-cell or open-cell based on the cell state. Closed-cell materials primarily function as sound insulation, while open-cell materials primarily function as sound absorption. The expansion rate of the expanded sealant is generally set between 800% and 1500%, preferably between 900% and 1200%. The expanded sealant typically utilizes a baking process involving electrophoretic coating curing to activate the foaming agent and cause it to expand. The typical heating conditions are 140℃ to 160℃ for 15 to 20 minutes. After being heated, the expansion material expands evenly outward to seal the entire cross-section and adheres firmly and reliably to the inner wall of the cavity. After cooling and solidification, it becomes an integral structure with the cavity.

[0047] Based on the above-mentioned double-layer partition sound-absorbing and sealing block, the present invention also provides a method for preparing the double-layer partition sound-absorbing and sealing block, the method comprising the following steps:

[0048] Step 1. Inject thermoplastic material into the injection mold to form an integrated bracket body consisting of a sound insulation and sealing block central partition 11, a sound absorption and sealing block central partition 21, a sealing block connecting plate 3, a sealing block mounting buckle, and a sealing block locking buckle.

[0049] Step 2. In the second injection mold, the sound-insulating expanding sealant and the sound-absorbing sound-insulating expanding sealant are respectively injected into the central partition 11 of the sound-insulating sealant block and the central partition 21 of the sound-absorbing sealant block, and then demolded to form a sealant block.

[0050] Step 3. The connection thickness between the sealing block connecting plate 3 and the central partition of the sealing block is less than the thickness of the sealing block connecting plate 3 and the central partition of the sealing block; the sealing block connecting plate 3 is provided with mounting buckle process holes I34 and II35 for installing the sealing block mounting buckle I31 and the sealing block mounting buckle II32.

[0051] Step 4. Bend the central partition 11 of the sound insulation sealant block and the central partition 21 of the sound absorption sealant block. After the central partition 11 of the sound insulation sealant block and the central partition 21 of the sound absorption sealant block are locked together by the sound absorption sealant block lock 24, the sound insulation sealant block lock 16 and the lock baffle 14, a double-layer expansion sealant block is formed.

[0052] Step 5. The distance between the central partition 11 of the sound insulation sealant block and the central partition 21 of the sound absorption sealant block is 30mm to 50mm.

[0053] The manufacturing methods for the sealant block bracket body and the expanding sealant body can employ injection molding methods such as co-injection molding, side-by-side injection molding, and two-color injection molding. First, the bracket body is injection molded by injecting thermoplastic material into the body injection mold in a direction perpendicular to the demolding direction of the movable molded half. After cooling, the bracket body is demolded. Next, the two expanding sealant materials are injected onto one side of the bracket, and then the sealant block is demolded.

[0054] In summary, the central partition of the sealant block and the expanding sealant body can be manufactured by injection molding. One injection molding method is two-stage injection molding. In the first step, thermoplastic material is injected into the injection mold to form an integrated support body consisting of the central partition body, the sealant block fixing clips, and the sealant block connecting plate. Then, in the second injection mold, sound-insulating expanding sealant and sound-absorbing sound-insulating expanding sealant are injected onto the central partition, followed by demolding to form the sealant block. The initial state of the block is shown in Figure 6(a), which is a semi-finished product. After bending as shown in Figure 6(b), the two central partitions are locked together to form the final state of the sealant block, 6(c). The two central partitions are locked together to form a double-layer expanding sealant block with a certain gap. This gap has been extensively verified and is generally set at 30mm to 50mm for the sound-absorbing and sound-insulating material combination, with 40mm being preferred. From the insertion loss test, it can provide the best noise reduction effect.

[0055] The expansion sealant block provided by this invention offers many advantages. For example, the injection molding process is simplified by using one-sided injection molding of the expansion sealant; and it solves the problem of poor sound insulation performance of single-layer sound insulation panels.

[0056] Based on the above-mentioned double-layer partition sound-absorbing and sealing block, the present invention also provides a method of using the double-layer partition sound-absorbing and sealing block, the method of use including:

[0057] a. Insert the sealing block mounting clips I 31 and II 32 into the sealing block mounting holes on the sill reinforcement plate 20 along the vertical sheet metal, and weld the sill reinforcement plate 20 with the sealing block to the inner sill plate 30 to form the sill cavity 40.

[0058] b. After the car body is welded, the heat-expandable sealant is thermally reacted in the electrophoretic oven. The heat-expandable sealant expands in the horizontal and vertical directions and adheres firmly and reliably to the inner wall of the door sill cavity sheet metal.

[0059] c. The cavities on the car body are filled with sealing blocks using operations a and b. All cavities on the car body are completely sealed, bonding the bracket body and sheet metal wall together, thus sealing the entire cavity and firmly and reliably adhering to the inner wall of the cavity. After cooling and solidification, it becomes an integral structure with the cavity.

[0060] The sealing block is installed on the sheet metal, and the sheet metal is welded to form a sealed cavity. After the body welding is completed, it is sent to the painting workshop. After pretreatment and electrophoresis, it enters the paint oven for baking and cooling. After the expanding sealant foams, it tightly bonds the bracket body to the inner body sheet metal, sealing the entire cross-sectional cavity. This effectively blocks the cavity channel, achieving full sealing and preventing noise from entering through the gaps in the body. This further improves the sound insulation, vibration reduction, and noise reduction in the car cabin, thus enhancing the NVH performance of the vehicle.

[0061] The following example illustrates the application of a sealing block in the internal cavity of a vehicle sill: A sealing block for the lower part of a sill is used to seal a vehicle body cavity at a specific cross-section. This sealing block includes a plastic bracket with sound insulation function, an expanding sound-insulating sealant that expands to fill the cavity cross-section when heated to a specific activation temperature, and an expanding sound-absorbing sealant. The two plastic brackets are fixed together by a bracket connecting plate to form the block bracket body, and one side of the block bracket is covered with both expanding sound-insulating and expanding sound-absorbing sealant. The sealants achieve a complete seal of the cavity through thermal expansion.

[0062] The sealant block support body includes a central partition 11 for sound-insulating and sealing blocks, a central partition 21 for sound-absorbing and sealing blocks, and a connecting plate 3 for the sealing blocks. Sealant is arranged on one side of the central partition. The central partition supports and fixes the expanding sound-insulating and sound-absorbing sealants (hereinafter collectively referred to as expanding sealants), and also limits the expansion direction of the expanding sealants. The shape of the central partition is designed according to the cross-section of the vehicle body cavity, maintaining consistency with the cavity contour. Several fixing posts are provided on the central partition, used to fix the expanding sealant to the central partition and also to fix the expanded sealant after expansion. During high-speed vehicle operation, noise generated in the side cavity is largely eliminated by each central partition, eliminating most of the sound transmitted from the previous partition. Through these two noise reduction processes, the noise gradually weakens, thus achieving double-layer sound insulation and effectively improving the overall NVH performance of the vehicle.

[0063] Two central partitions are connected together by a sealing block connecting plate. The sealing block connecting plate has two mounting clips for fixing the sealing blocks to the cavity sheet metal. One side of the connecting plate has expanding sealant to seal the clip mounting holes, ensuring the integrity of the entire sealed cavity. Two through holes are provided on the sealing block connecting plate; the use of clips simplifies the injection mold during manufacturing, improving production efficiency.

[0064] The two central partitions are equipped with a locking device on one side to fix the two partitions together. The central partitions are initially in the same plane. The connection between the partition and the bracket connecting plate can be bent. The produced sealing block is bent and the two central partitions are parallel to each other through the locking device before it can be installed on the vehicle.

[0065] The central partition and the sealing block connecting plate are injection molded from a thermoplastic synthetic material, typically polyamide or polyimide, with a heat distortion temperature exceeding 250°C, to ensure the sealing block maintains its shape during and after the electrophoretic coating oven curing process. Other similar materials can be used depending on the required physical properties, and glass fiber reinforcement can also be added.

[0066] The shape of the expanding sealant corresponds to but is smaller than the cross-sectional shape of the cavity. A 3mm to 5mm gap is typically left between the expanding sealant and the cavity wall to facilitate the smooth passage of various coating solutions. The expanding sealant has a specific thermal expansion activation temperature. The expanding sealant comprises a polymer-based adhesive and a foaming agent. The polymer-based adhesive can be any one of ethylene-vinyl acetate copolymer, ethylene-methacrylate copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, polyvinyl butyral, styrene-butadiene rubber, etc. The expanding sealant typically utilizes a baking process similar to that used for curing electrophoretic paint to activate the foaming agent and cause it to expand. The typical heating conditions are 140℃ to 180℃ for 10 to 30 minutes. After being heated, the expanding material expands uniformly outwards, sealing the entire cross-section.

[0067] To further enhance sound insulation and absorption, the expanding sealant is designed and manufactured to be evenly applied to one side of the central partition, rather than being wrapped around the central partition in the traditional way, and is fixed to the partition by several fixing posts to ensure that the thermal expansion material does not detach from the support body before and after thermal expansion.

[0068] The manufacturing methods for the sealant block bracket body and the expanding sealant body can employ injection molding methods such as co-injection molding, side-by-side injection molding, and two-color injection molding. First, the bracket body is injection molded by injecting thermoplastic material into the body injection mold in a direction perpendicular to the demolding direction of the movable molded half. After cooling, the bracket body is demolded. Next, the two expanding sealant materials are injected onto one side of the bracket, and then the sealant block is demolded.

[0069] The sealing block is installed on the sheet metal, and the sheet metal is welded to form a sealed cavity. After the body welding is completed, it is sent to the painting workshop. After pretreatment and electrophoresis, it enters the paint oven for baking and cooling. After the expanding sealant foams, it tightly bonds the bracket body to the inner body sheet metal, sealing the entire cross-sectional cavity. This effectively blocks the cavity channel, achieving full sealing and preventing noise from entering through the gaps in the body. This further improves the sound insulation, vibration reduction, and noise reduction in the car cabin, thus enhancing the NVH performance of the vehicle.

[0070] In addition to being applied to the internal cavity structure of the vehicle body door sill, this invention can also be applied to typical cavities of the vehicle body, such as the wheel arch cavity, front and rear longitudinal beams, C-pillar cavity, and A-pillar cavity.

[0071] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the technical solution of the present invention, or the direct application of the concept and technical solution of the present invention to other occasions without modification, are all within the protection scope of the present invention.

Claims

1. A double-layer partition sound-absorbing and sealing block, characterized in that: The system includes a sealing block body (10) that fills a cavity in the vehicle body. The sealing block body (10) includes a sound-insulating sealing block (1), a sound-absorbing sealing block (2), and a sealing block connecting plate (3). The sound-insulating sealing block (1) is connected to one side of the sealing block connecting plate (3), and the sound-absorbing sealing block (2) is connected to the other side of the sealing block connecting plate (3). The sound-insulating sealing block (1) and the sound-absorbing sealing block (2) are arranged opposite to each other on the sealing block connecting plate (3) to form a double-layer sealing block. The sealing block connecting plate (3) is provided with a mounting plate. The sealing block body (10) is installed in the vehicle cavity through the mounting buckle on the sealing block connecting plate (3); the sound insulation sealing block (1) includes a sound insulation sealing block central partition (11), a sound insulation sealing block expansion sealant (12) and a sound insulation sealing block fixing post (13). The sound insulation sealing block expansion sealant (12) is fixedly connected to the sound insulation sealing block central partition (11) through the sound insulation sealing block fixing post (13). The sound insulation sealing block expansion sealant (12) is evenly attached to the outer side of the sound insulation sealing block central partition (11). The sound insulation sealing block (1) also includes a locking baffle (14) and a sound insulation sealing block lock (16). The locking baffle (14) and the sound insulation sealing block lock (16) are disposed on the inner side of the central partition (11) of the sound insulation sealing block. A snap-fit ​​fixing cavity (15) is formed between the locking baffle (14) and the sound insulation sealing block lock (16) to absorb sound. The sound-absorbing sealant block (2) includes a central partition (21), an expanding sealant (22), and a fixing post (23). The expanding sealant (22) is fixedly connected to the central partition (21) via the fixing post (23). The expanding sealant (22) is evenly attached to the outer surface of the central partition (21). The sound-absorbing sealing block (2) also includes a sound-absorbing sealing block buckle (24), which is located on the inner side of the central partition (21) of the sound-absorbing sealing block. The sound-absorbing sealing block buckle (24) is inserted into the buckle fixing cavity (15) and engaged with the sound-insulating sealing block buckle (16).

2. The double-layer partition sound-absorbing and sealing block as described in claim 1, characterized in that: The sound insulation sealing block (1) and the sound absorption sealing block (2) are both made of thermoplastic material. The sound insulation sealing block (1) and the sound absorption sealing block (2) have the same shape. The shape of the sound insulation sealing block (1) and the sound absorption sealing block (2) corresponds to the cross-sectional shape of the vehicle body cavity, but is smaller than the shape of the vehicle body cavity. A gap of 3mm to 5mm is provided between the sound insulation sealing block (1) and the sound absorption sealing block (2) and the cavity wall of the vehicle body cavity.

3. A double-layer partition sound-absorbing and sealing block as described in claim 1 or 2, characterized in that: The sound insulation sealant block central partition (11) and the sound absorption sealant block central partition (21) are connected together by the sealant block connecting plate (3) and are injection molded together by injection molding process. The thickness of the sound insulation sealant block central partition (11) and the sound absorption sealant block central partition (21) is 1mm to 3mm. The thickness of the sound insulation sealant block expansion sealant (12) and the sound absorption sealant block expansion sealant (22) is 2mm to 4mm.

4. The double-layer partition sound-absorbing and sealing block as described in claim 3, characterized in that: The sealing block connecting plate (3) is provided with a sealing block mounting buckle I (31) and a sealing block mounting buckle II (32) on the side opposite to the sound insulation sealing block (1) and the sound absorption sealing block (2). The sealing block body (10) is fixedly installed on the sheet metal of the vehicle body cavity by the sealing block mounting buckle I (31) and the sealing block mounting buckle II (32).

5. A method for preparing a double-layer partition sound-absorbing and sealing block, characterized in that: The preparation method of the double-layer partition sound-absorbing and sealing block according to any one of claims 1 to 4 includes the following steps: Step 1. Inject thermoplastic material into the injection mold to form an integrated bracket body consisting of a central partition (11) of sound-insulating and sealing rubber block, a central partition (21) of sound-absorbing and sealing rubber block, a connecting plate (3) of sealing rubber block, a mounting buckle for sealing rubber block, and a locking buckle for sealing rubber block. Step 2. In the second injection mold, the sound-insulating expanding sealant and the sound-absorbing sound-insulating expanding sealant are respectively injected into the central partition (11) of the sound-insulating sealant block and the central partition (21) of the sound-absorbing sealant block, and then demolded to form a sealant block; Step 3. The connection thickness between the central partition plate (3) of the sealing block and the central partition plate (11) of the sound insulation sealing block or the central partition plate (21) of the sound absorption sealing block is less than the connection thickness between the central partition plate (3) of the sealing block and the central partition plate (11) of the sound insulation sealing block or the central partition plate (21) of the sound absorption sealing block; the sealing block connecting plate (3) is provided with mounting buckle process holes I (34) and II (35) for installing the sealing block mounting buckle I (31) and the sealing block mounting buckle II (32); Step 4. Bend the central partition (11) of the sound insulation sealant block and the central partition (21) of the sound absorption sealant block. After the central partition (11) of the sound insulation sealant block and the central partition (21) of the sound absorption sealant block are locked together by the sound absorption sealant block buckle (24), the sound insulation sealant block buckle (16) and the buckle baffle (14), a double-layer expansion sealant block is formed. Step 5. The distance between the central partition (11) of the sound insulation sealant block and the central partition (21) of the sound absorption sealant block is 0mm to 50mm.

6. A method for using a double-layer partition sound-absorbing and sealing block, characterized in that: The method of using a double-layer partition sound-absorbing and sealing block according to any one of claims 1 to 4 includes: a. Insert the sealing block mounting clip I (31) and the sealing block mounting clip II (32) into the sealing block mounting hole on the sill reinforcement plate (20) along the vertical sheet metal, and weld the sill reinforcement plate (20) with the sealing block to the sill inner plate (30) to form a sill cavity (40). b. After the car body is welded, the heat-expandable sealant is thermally reacted in the electrophoretic oven. The heat-expandable sealant expands in the horizontal and vertical directions and adheres firmly and reliably to the inner wall of the door sill cavity sheet metal. c. The cavities on the car body are filled with sealing blocks using operations a and b. All cavities on the car body are completely sealed, bonding the bracket body and sheet metal wall together, thus sealing the entire cavity and firmly and reliably adhering to the inner wall of the cavity. After cooling and solidification, it becomes an integral structure with the cavity.

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