Expansion sheet for sealing vehicle body cavity and vehicle body cavity structure having the expansion sheet

Abstract

The present invention discloses an expansion sheet for sealing a vehicle body cavity and a vehicle body cavity structure having the expansion sheet, which includes an expansion sealing block and a fixing part for fixing the expansion sealing block to a vehicle body sheet metal; the expansion sealing block includes a single-layer expansion sealing portion composed of a single-layer expansion sealing strip and a multi-layer expansion sealing portion composed of a multi-layer expansion sealing strip, the fixing part includes a first fixing part for fixing the single-layer expansion sealing portion to the vehicle body sheet metal and a second fixing part for fixing the multi-layer expansion sealing portion to the vehicle body sheet metal, and there is a gap between two adjacent layers of expansion sealing strips of the multi-layer expansion sealing portion. The core part of the expansion sheet is the expansion sealing block, which is composed of two different forms of sealing parts. Among them, the single-layer expansion sealing part can play a sealing role in a specific vehicle body cavity part. The multi-layer expansion sealing part makes its sealing performance may have better performance in some more complex or higher sealing requirements of the vehicle body cavity area.

Description

Technical Field

[0001] The invention relates to the technical field of automobile structures, in particular to an expansion sheet for sealing a vehicle body cavity and a vehicle body cavity structure having the expansion sheet. Background Art

[0002] During the driving of the vehicle, many noise sources, such as the noise generated by the operation of the engine and motor, the friction between the tires and the ground, and the air noise during driving, will be transmitted into the vehicle through the cavities of the A, B, C, and D pillars. These noises cause resonance in the cavities, seriously interfering with the comfort experience of the driver and passengers. Nowadays, people's expectations for the comfort of the entire vehicle continue to rise. NVH quietness is a key performance indicator of the car. The noise, vibration and comfort factors it covers directly influence consumers' evaluation of the car experience. Therefore, the perception of car noise has become an increasingly important aspect for consumers.

[0003] As an effective method for cavity partition, the expansion sealing block has been widely used in filling the side wall cavity (A, B, C, D pillars). The specific operation is to place the expansion sealing block inside the cavity of the body section, and then heat it in an electrophoretic drying furnace. The foaming material EVA is fully expanded after being baked in the high temperature environment of 140℃ to 180℃ in the electrophoretic drying furnace for about 20 minutes, thereby sealing the cavity. In this way, the propagation of air noise and structure-borne noise can be effectively blocked, playing a positive role in sealing, blocking, shock absorption and noise reduction.

[0004] In order to meet the requirements of vehicle styling design and structural strength, many areas of the modern body outer panel adopt negative demolding technology. This process makes the gap of the body outer panel too small in some areas during the installation process, about 2mm, and the cavity gap of some areas is too large after the installation is completed, exceeding 20mm. Under this complex body structure, the traditional two-color injection expansion sealing block design is difficult to achieve the goal of avoiding interference from the upper part and effectively filling the large cavity at the same time. And because the position is in a vertical state, if the traditional pure EVA foam extrusion material design is used, the foam material will drip and sag in the Z direction after being heated and baked due to the lack of skeleton support, which will eventually cause the sealing function to fail. Summary of the invention

[0005] The purpose of the present invention is to solve the deficiencies of the above-mentioned background technology and to provide a vehicle body cavity sealing expansion sheet and a vehicle body cavity structure with the expansion sheet that can meet the cavity noise reduction and sealing requirements of the special design of the vehicle.

[0006] To achieve this purpose, the present invention is designed to provide an expansion sheet for sealing a vehicle body cavity, which includes an expansion sealing block and a fixing member for fixing the expansion sealing block to a vehicle body sheet metal;

[0007] The expansion sealing block includes a single-layer expansion sealing portion composed of a single-layer expansion sealing strip and a multi-layer expansion sealing portion composed of a multi-layer expansion sealing strip. The fixing part includes a first fixing part for fixing the single-layer expansion sealing portion to the body sheet metal and a second fixing part for fixing the multi-layer expansion sealing portion to the body sheet metal. There is a gap between two adjacent layers of expansion sealing strips of the multi-layer expansion sealing portion.

[0008] Furthermore, the expansion sealing block includes a bendable flexible support frame and a foaming material covering and fixed to upper and lower side surfaces of the flexible support frame.

[0009] Furthermore, the multi-layer expansion sealing part includes three layers of expansion sealing strips, including a base expansion sealing strip located at the bottom layer, a middle expansion sealing strip located above the base expansion sealing strip, and an upper expansion sealing strip located above the middle expansion sealing strip.

[0010] Furthermore, one side of the base expansion sealing strip is bent four times so that the outer portion of the base expansion sealing strip forms the middle expansion sealing strip and the middle portion of the base expansion sealing strip forms the upper expansion sealing strip.

[0011] Furthermore, the bottom surface of the middle-layer expansion sealing strip is fixed to the top surface of the base-layer expansion sealing strip, and there is a gap between the middle-layer expansion sealing strip and the upper-layer expansion sealing strip.

[0012] Furthermore, one end of the second fixing member vertically passes through the middle-layer expansion sealing strip and the base-layer expansion sealing strip.

[0013] Furthermore, one end of the first fixing member vertically passes through the single-layer expansion sealing portion.

[0014] Furthermore, the first fixing member and the second fixing member are both screw-type buckles.

[0015] Furthermore, a vehicle body cavity structure with an expansion sheet for sealing the vehicle body cavity includes a vehicle body cavity, which includes a strip cavity and a negative angle cavity connected to the strip cavity at an acute angle, the single-layer expansion sealing part is fixed to the inside of the strip cavity by the first fixing part, and the multi-layer expansion sealing part is fixed to the inside of the negative angle cavity by the second fixing part.

[0016] Furthermore, there is a gap between the single-layer expansion sealing portion and the multi-layer expansion sealing portion and the inner surface of the vehicle body cavity.

[0017] The beneficial effects of the present invention are as follows: the core part of the expansion sheet designed by the present invention is the expansion sealing block, which is composed of two different forms of sealing parts. Among them, the single-layer expansion sealing part is composed of a single-layer expansion sealing strip. This structure is relatively simple and direct, and can play a sealing role in a specific body cavity. The multi-layer expansion sealing part is composed of multiple layers of expansion sealing strips. The multi-layer design makes its sealing performance may have better performance in some more complex or high-sealing body cavity areas. It is particularly worth mentioning that there is a gap between two adjacent layers of expansion sealing strips in the multi-layer expansion sealing part. The existence of this gap has its specific significance. On the one hand, it may reserve space for the expansion of the expansion sealing strip under conditions such as heat, so that each layer of expansion sealing strip can expand more fully without interfering with each other, thereby better filling the body cavity and achieving a better sealing effect; on the other hand, the gap may also play a role in buffering or regulating the airflow or electrophoretic liquid flow to a certain extent, which helps to improve the stability of the overall sealing performance. In order to accurately and firmly fix the expansion sealing block on the body sheet metal, a special fixing is set. The first fixing part is used to fix the single-layer expansion seal part on the body sheet metal. It can ensure that the single-layer expansion seal strip maintains a stable position in the corresponding part of the body, and prevents it from shifting due to vibration and other reasons during the driving process of the vehicle, which affects the sealing effect. The second fixing part is for the multi-layer expansion seal part, which is responsible for fixing it on the body sheet metal, and also ensures the stable installation of the multi-layer expansion seal strip in the specific cavity of the body, laying the foundation for achieving good sealing function. The expansion seal strip will expand due to heat. For the single-layer expansion seal part, its single-layer expansion seal strip will gradually fill the gap between the body sheet metal and other parts to form a sealing barrier. For the multi-layer expansion seal part, each layer of the expansion seal strip will expand on its own level. Since there is a gap between the adjacent two layers, they can expand more freely, making full use of these gap spaces to further fill every corner of the body cavity, and achieve a more rigorous sealing effect. The expansion seal block is firmly fixed on the body sheet metal by the fixing part, ensuring that the position of the entire expansion seal block remains relatively unchanged during the expansion or contraction of the expansion seal strip, and the body cavity can always be accurately sealed. The strip cavities in the body cavity are arranged in a fixed direction. This strip design gives it a certain directionality and continuity in the body structure, and may form a relatively regular long strip space in a certain area of ​​the body. For example, it may extend along the longitudinal or transverse direction of the body, and its shape and layout are often adapted to the overall structure of the body and the installation requirements of related components, providing certain spatial conditions for the vehicle's structural strength, wiring, etc. Unlike the strip cavity, the negative angle cavity is connected to the strip cavity at an acute angle. The existence of the negative angle cavity increases the complexity and diversity of the body cavity structure.The way it is connected at an acute angle means that it forms a special angle relationship with the strip cavity in space. This angle relationship may be to meet the structural requirements of certain specific parts of the vehicle body. For example, at the corners and joints of the vehicle body, the space can be better utilized by setting a negative angle cavity. It may also be closely related to the aerodynamic design of the vehicle and the layout of component installation. The single-layer expansion sealing part is fixed to the inside of the strip cavity by the first fixing member. Since the strip cavity has the characteristics of being arranged along a fixed direction and is relatively regular, this arrangement of the single-layer expansion sealing part can better adapt to its shape. The single-layer expansion sealing strip can be laid along the length direction of the strip cavity and firmly fixed on the inner wall of the cavity by the first fixing member. Such an arrangement can more efficiently realize the sealing function in a relatively regular space such as the strip cavity. By utilizing the continuity of the strip cavity, the single-layer expansion sealing strip can fill its internal space more evenly, play an effective sealing role on the strip cavity, and prevent external dust, water vapor, etc. from entering the interior of the vehicle body through the strip cavity, affecting the normal operation and service life of the vehicle. The multi-layer expansion sealing part is fixed inside the negative angle cavity by the second fixing part. The shape of the negative angle cavity is relatively complex, and it is connected to the strip cavity at an acute angle. Its spatial angle and shape have certain particularities. The multi-layer expansion sealing part is composed of multiple layers of expansion sealing strips and there is a gap between two adjacent layers, which makes it more suitable for sealing operations in such complex negative angle cavities. The multi-layer expansion sealing strip can better fill the corners of the negative angle cavity according to the irregular shape of the negative angle cavity and the gap between two adjacent layers. It is fixed to the inner wall of the negative angle cavity by the second fixing part, thereby achieving a tighter sealing effect on the negative angle cavity, effectively avoiding the sealing loopholes that may be caused by the complexity of the negative angle cavity, and ensuring the overall sealing performance of the vehicle body cavity. By accurately fixing the single-layer expansion sealing part and the multi-layer expansion sealing part inside the strip cavity and the negative angle cavity respectively, a more optimized sealing effect can be achieved for vehicle body cavities of different shapes and characteristics. This targeted arrangement makes full use of the characteristics of the two expansion seals and the structural features of the two cavities, which greatly improves the overall sealing integrity of the body cavity and effectively reduces the interference of external factors on the interior of the body, such as the intrusion of dust, water vapor, noise, etc., providing the vehicle with a relatively clean, quiet and dry internal environment. The existence of strip cavities and negative angle cavities in the body cavity structure and the reasonable arrangement of expansion sheets therein fully reflect the adaptation to the diversity of body structures. The body structure of a vehicle is complex and diverse, and different parts have different shapes, angles and space requirements. This design can effectively realize the sealing function of the body cavity while meeting the requirements of the body structure, so that the vehicle can still maintain good sealing performance under a complex structure, which is of great significance to the performance, life and comfort of the vehicle's passengers. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A three-dimensional diagram of an expansion sheet for sealing a vehicle body cavity in the present invention;

[0019] Figure 2 A perspective view of a vehicle body cavity structure having an expansion sheet for sealing a vehicle body cavity in the present invention;

[0020] Figure 3 An exploded view of a vehicle body cavity structure having an expansion sheet for sealing a vehicle body cavity in the present invention;

[0021] Figure 4 It is a front view of a vehicle body cavity structure having an expansion sheet for sealing a vehicle body cavity in the present invention;

[0022] Figure 5 for Figure 4 Middle AA section;

[0023] Among them, 1 is an expansion sealing block (1.1 is a single-layer expansion sealing part, 1.2 is a multi-layer expansion sealing part), 2 is a first fixing part, 3 is a second fixing part, 4 is a flexible supporting skeleton, 5 is a foaming material, 6 is a base expansion sealing strip, 7 is a middle expansion sealing strip, 8 is an upper expansion sealing strip, 9 is a strip-shaped cavity, 10 is a negative angle cavity, 11 is a side panel sheet metal, 12 is a water flow channel sheet metal, and 13 is a rear pillar inner support sheet metal. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. In the description of the present invention, it should be understood that the orientations or positional relationships indicated by the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0025] like Figure 1 As shown, the expansion sheet for sealing a vehicle body cavity designed in the present invention comprises an expansion sealing block 1 and a fixing member for fixing the expansion sealing block 1 to a vehicle body sheet metal.

[0026] In some embodiments, the expansion sealing block 1 includes a single-layer expansion sealing portion 1.1 composed of a single-layer expansion sealing strip and a multi-layer expansion sealing portion 1.2 composed of a multi-layer expansion sealing strip, the fixing part includes a first fixing part 2 for fixing the single-layer expansion sealing portion 1.1 to the body sheet metal and a second fixing part 3 for fixing the multi-layer expansion sealing portion 1.2 to the body sheet metal, and there is a gap between two adjacent layers of expansion sealing strips of the multi-layer expansion sealing portion 1.2.

[0027] Embodiment 1

[0028] The expansion sealing block 1 includes a bendable flexible support frame 4 and a foaming material 5 covering and fixed to the upper and lower surfaces of the flexible support frame 4. The multi-layer expansion sealing part 1.2 includes three layers of expansion sealing strips, including a base expansion sealing strip 6 located at the bottom layer, a middle expansion sealing strip 7 located above the base expansion sealing strip 6, and an upper expansion sealing strip 8 located above the middle expansion sealing strip 7.

[0029] Embodiment 2

[0030] On the basis of the first embodiment, the structure of the multi-layer expansion sealing part 1.2 is further optimized: one side of the base expansion sealing strip 6 is bent four times so that the outer part of the base expansion sealing strip 6 forms a middle expansion sealing strip 7, and the middle part of the base expansion sealing strip 6 forms an upper expansion sealing strip 8. The bottom surface of the middle expansion sealing strip 7 is fixed to the top surface of the base expansion sealing strip 6, and there is a gap between the middle expansion sealing strip 7 and the upper expansion sealing strip 8.

[0031] Embodiment 3

[0032] Based on the second embodiment, the arrangement structure of the second fixing member 3 and the first fixing member 2 is further optimized: one end of the second fixing member 3 vertically passes through the middle expansion sealing strip 7 and the base expansion sealing strip 6. One end of the first fixing member 2 vertically passes through the single-layer expansion sealing portion 1.1.

[0033] Embodiment 4

[0034] On the basis of certain embodiments or embodiment one or embodiment two or embodiment three, the structures of the first fixing member 2 and the third fixing member 3 are further optimized and designed: the first fixing member 2 and the second fixing member 3 are both screw-type buckles.

[0035] Embodiment 5

[0036] like Figure 2As shown in FIG. 5 , a vehicle body cavity structure with an expansion sheet for sealing a vehicle body cavity designed based on the first embodiment, the second embodiment, the third embodiment, or the fourth embodiment includes a vehicle body cavity, which includes a strip cavity 9 and a negative angle cavity 10 connected to the strip cavity 9 at an acute angle, a single-layer expansion sealing portion 1.1 is fixed inside the strip cavity 9 by a first fixing member 2, and a multi-layer expansion sealing portion 1.2 is fixed inside the negative angle cavity 10 by a second fixing member 3. There is a gap between the single-layer expansion sealing portion 1.1 and the multi-layer expansion sealing portion 1.2 and the inner surface of the vehicle body cavity.

[0037] Specifically, a specific vehicle body structure of a fifth embodiment is provided.

[0038] The vehicle body structure includes a side panel 11, a water trough panel 12 and a rear pillar inner support panel 13, which form a negative angle flange cavity structure, and an expansion sealing block 1 is arranged in the negative angle flange cavity structure. The expansion sealing block 1 is first assembled on the rear pillar inner support plate 13 through a snap (a first fixing member 2 and a second fixing member 3), and then the side panel 11 and the water trough panel 12 are welded together into an assembly, and then assembled with the rear pillar inner support plate 13 in the Y direction. In order to avoid interference with the expansion sealing block 1 due to narrow local gaps and loose sealing due to excessive end cavity gaps after assembly, the expansion sealing block 1 is extruded integrally with the foaming material 5 using a flexible support skeleton 4, and knotting is used at the position with large cavities. The rear end of the upper part can be effectively rebounded, and the knotted area structure can effectively ensure that the foam body is sufficient after being heated and expanded to achieve cavity sealing. At the same time, after the expansion seal block 1 is fixed on the sheet metal, a fluid cavity is formed between the rubber block body and the sheet metal. The above structure forms a fluid cavity between the expansion seal block 1 and the sheet metal, which facilitates the inflow of relevant pre-treatment tank liquid and electrophoresis tank liquid, avoids the problem of poor electrophoresis between the expansion seal block 1 and the sheet metal, and enhances the anti-corrosion ability of the vehicle body.

[0039] The expansion sealing block 1 designed by the present invention is composed of a foamed thermoplastic elastomer (foamed material 5), a foamed material supporting flexible skeleton body (flexible support skeleton 4), and a fixing buckle (a first fixing member 2 and a second fixing member 3). When assembled on the inner wall of the inner support plate 13 of the rear pillar in the welding workshop, the foamed material EVA will be baked at high temperature in the electrophoresis drying furnace of the paint workshop to foam and fill the cavity gap, thereby effectively reducing and isolating the cavity noise generated by the vehicle during high-speed driving. Since the expansion sealing block 1 is installed in the cavity surrounded by the inner support plate 13 of the rear pillar, the side panel sheet metal 11 and the water trough panel sheet metal 12, the cavity gap of the local position of the cavity surrounded by the water trough panel sheet metal 12 and the side panel sheet metal 11 and the inner support plate 13 of the rear pillar is too large due to the influence of the Y-upward part of the side panel sheet metal 11 and the water trough panel sheet metal 12. If the traditional two-color injection molding structure is adopted, under the condition of ensuring non-interference, there will be problems such as too little local foaming material and poor sealing of the cavity gap. If the traditional pure EVA foam material structure is used, the cavity gap is too large after assembly and there is no supporting structure in the Z direction. Under high-temperature baking conditions, the foam material will drip and fall in the Z direction, causing sealing failure. Therefore, the expansion sealing block 1 uses a foam material to support the flexible skeleton body (high-rebound aluminum material) as support, and a knotted design is adopted at the end position. When the upper parts are assembled, the interference part can be deformed and automatically rebound after assembly. The knotted position at the end can effectively solve the sealing problem of excessive local cavity gaps due to sufficient foam material. Since the knotted position at the end of the expansion sealing block 1 and the support plate 13 installed in the rear pillar share a fixed buckle, the firmness and stability of the knotted part of the end are guaranteed, and to a certain extent, it is also guaranteed that the entire cavity gap can be filled after rebound; the assembly process is simplified, and quick installation is achieved.

[0040] In summary, the core part of the expansion sheet designed by the present invention is the expansion sealing block, which is composed of two different forms of sealing parts. Among them, the single-layer expansion sealing part is composed of a single-layer expansion sealing strip. This structure is relatively simple and direct, and can play a sealing role in a specific body cavity. The multi-layer expansion sealing part is composed of multiple layers of expansion sealing strips. The multi-layer design makes its sealing performance in some more complex or higher sealing requirements of the body cavity area may have better performance. It is particularly worth mentioning that there is a gap between the two adjacent layers of expansion sealing strips of the multi-layer expansion sealing part. The existence of this gap has its specific significance. On the one hand, it may reserve space for the expansion of the expansion sealing strip under conditions such as heat, so that each layer of expansion sealing strip can expand more fully without interfering with each other, thereby better filling the body cavity and achieving a better sealing effect; on the other hand, the gap may also play a role in buffering or regulating the airflow or electrophoretic liquid flow to a certain extent, which helps to improve the stability of the overall sealing performance. In order to accurately and firmly fix the expansion sealing block on the body sheet metal, a special fixing is set. The first fixing part is used to fix the single-layer expansion seal part on the body sheet metal. It can ensure that the single-layer expansion seal strip maintains a stable position in the corresponding part of the body, and prevents it from shifting due to vibration and other reasons during the driving process of the vehicle, which affects the sealing effect. The second fixing part is for the multi-layer expansion seal part, which is responsible for fixing it on the body sheet metal, and also ensures the stable installation of the multi-layer expansion seal strip in the specific cavity of the body, laying the foundation for achieving good sealing function. The expansion seal strip will expand due to heat. For the single-layer expansion seal part, its single-layer expansion seal strip will gradually fill the gap between the body sheet metal and other parts to form a sealing barrier. For the multi-layer expansion seal part, each layer of the expansion seal strip will expand on its own level. Since there is a gap between the adjacent two layers, they can expand more freely, making full use of these gap spaces to further fill every corner of the body cavity, and achieve a more rigorous sealing effect. The expansion seal block is firmly fixed on the body sheet metal by the fixing part, ensuring that the position of the entire expansion seal block remains relatively unchanged during the expansion or contraction of the expansion seal strip, and the body cavity can always be accurately sealed. The strip cavities in the body cavity are arranged in a fixed direction. This strip design gives it a certain directionality and continuity in the body structure, and may form a relatively regular long strip space in a certain area of ​​the body. For example, it may extend along the longitudinal or transverse direction of the body, and its shape and layout are often adapted to the overall structure of the body and the installation requirements of related components, providing certain spatial conditions for the vehicle's structural strength, wiring, etc. Unlike the strip cavity, the negative angle cavity is connected to the strip cavity at an acute angle. The existence of the negative angle cavity increases the complexity and diversity of the body cavity structure.The way it is connected at an acute angle means that it forms a special angle relationship with the strip cavity in space. This angle relationship may be to meet the structural requirements of certain specific parts of the vehicle body. For example, at the corners and joints of the vehicle body, the space can be better utilized by setting a negative angle cavity. It may also be closely related to the aerodynamic design of the vehicle and the layout of component installation. The single-layer expansion sealing part is fixed to the inside of the strip cavity by the first fixing member. Since the strip cavity has the characteristics of being arranged along a fixed direction and is relatively regular, this arrangement of the single-layer expansion sealing part can better adapt to its shape. The single-layer expansion sealing strip can be laid along the length direction of the strip cavity and firmly fixed on the inner wall of the cavity by the first fixing member. Such an arrangement can more efficiently realize the sealing function in a relatively regular space such as the strip cavity. By utilizing the continuity of the strip cavity, the single-layer expansion sealing strip can fill its internal space more evenly, play an effective sealing role on the strip cavity, and prevent external dust, water vapor, etc. from entering the interior of the vehicle body through the strip cavity, affecting the normal operation and service life of the vehicle. The multi-layer expansion sealing part is fixed inside the negative angle cavity by the second fixing part. The shape of the negative angle cavity is relatively complex, and it is connected to the strip cavity at an acute angle. Its spatial angle and shape have certain particularities. The multi-layer expansion sealing part is composed of multiple layers of expansion sealing strips and there is a gap between two adjacent layers, which makes it more suitable for sealing operations in such complex negative angle cavities. The multi-layer expansion sealing strip can better fill the corners of the negative angle cavity according to the irregular shape of the negative angle cavity and the gap between two adjacent layers. It is fixed to the inner wall of the negative angle cavity by the second fixing part, thereby achieving a tighter sealing effect on the negative angle cavity, effectively avoiding the sealing loopholes that may be caused by the complexity of the negative angle cavity, and ensuring the overall sealing performance of the vehicle body cavity. By accurately fixing the single-layer expansion sealing part and the multi-layer expansion sealing part inside the strip cavity and the negative angle cavity respectively, a more optimized sealing effect can be achieved for vehicle body cavities of different shapes and characteristics. This targeted arrangement makes full use of the characteristics of the two expansion seals and the structural features of the two cavities, which greatly improves the overall sealing integrity of the body cavity and effectively reduces the interference of external factors on the interior of the body, such as the intrusion of dust, water vapor, noise, etc., providing the vehicle with a relatively clean, quiet and dry internal environment. The existence of strip cavities and negative angle cavities in the body cavity structure and the reasonable arrangement of expansion sheets therein fully reflect the adaptation to the diversity of body structures. The body structure of a vehicle is complex and diverse, and different parts have different shapes, angles and space requirements. This design can effectively realize the sealing function of the body cavity while meeting the requirements of the body structure, so that the vehicle can still maintain good sealing performance under a complex structure, which is of great significance to the performance, life and comfort of the vehicle's passengers.

[0041] Finally, it should be pointed out that the above embodiments are only representative examples of the present invention. Obviously, the present invention is not limited to the above embodiments, and there are many variations. Any simple modification, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention should be considered to belong to the protection scope of the present invention.

Claims

1. An expansion sheet for sealing a vehicle body cavity, characterized in that: It comprises an expansion sealing block (1) and a fixing piece used for fixing the expansion sealing block (1) on a body sheet metal; The expansion sealing block (1) comprises a single-layer expansion sealing portion (1.1) composed of a single-layer expansion sealing strip and a multi-layer expansion sealing portion (1.2) composed of a multi-layer expansion sealing strip, the fixing member comprises a first fixing member (2) for fixing the single-layer expansion sealing portion (1.1) to the body sheet metal and a second fixing member (3) for fixing the multi-layer expansion sealing portion (1.2) to the body sheet metal, and there is a gap between two adjacent layers of expansion sealing strips of the multi-layer expansion sealing portion (1.2).

2. The expansion sheet for sealing a vehicle body cavity according to claim 1, characterized in that: The expansion sealing block (1) comprises a bendable flexible support frame (4) and a foaming material (5) covering and fixed to the upper and lower surfaces of the flexible support frame (4).

3. The expansion sheet for sealing a vehicle body cavity according to claim 2, characterized in that: The multi-layer expansion sealing part (1.2) comprises three layers of expansion sealing strips, including a base expansion sealing strip (6) located at the bottom layer, a middle expansion sealing strip (7) located above the base expansion sealing strip (6), and an upper expansion sealing strip (8) located above the middle expansion sealing strip (7).

4. The expansion sheet for sealing a vehicle body cavity according to claim 3, characterized in that: One side of the base expansion sealing strip (6) is bent four times so that the outer portion of the base expansion sealing strip (6) forms the middle expansion sealing strip (7) and the middle portion of the base expansion sealing strip (6) forms the upper expansion sealing strip (8).

5. The expansion sheet for sealing a vehicle body cavity according to claim 4, characterized in that: The bottom surface of the middle-layer expansion sealing strip (7) is fixedly attached to the top surface of the base-layer expansion sealing strip (6), and a gap exists between the middle-layer expansion sealing strip (7) and the upper-layer expansion sealing strip (8).

6. The expansion sheet for sealing a vehicle body cavity according to claim 5, characterized in that: One end of the second fixing member (3) vertically passes through the middle-layer expansion sealing strip (7) and the base-layer expansion sealing strip (6).

7. The expansion sheet for sealing a vehicle body cavity according to claim 1, characterized in that: One end of the first fixing member (2) vertically passes through the single-layer expansion sealing portion (1.1).

8. The expansion sheet for sealing a vehicle body cavity according to claim 1, characterized in that: The first fixing member (2) and the second fixing member (3) are both screw-type buckles.

9. A vehicle body cavity structure having an expansion sheet for sealing a vehicle body cavity according to any one of claims 1 to 8, comprising a vehicle body cavity, which comprises a strip-shaped cavity (9) and a negative angle cavity (10) connected to the strip-shaped cavity (9) at an acute angle, characterized in that: The single-layer expansion sealing part (1.1) is fixed inside the strip-shaped cavity (9) via the first fixing part (2), and the multi-layer expansion sealing part (1.2) is fixed inside the negative-angle cavity (10) via the second fixing part (3).

10. The vehicle body cavity structure having an expansion sheet for sealing a vehicle body cavity according to claim 9, characterized in that: There is a gap between the single-layer expansion seal (1.1) and the multi-layer expansion seal (1.2) and the inner surface of the vehicle body cavity.

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