Methods for sealing and / or reinforcing cavities

Abstract

This invention relates to a method for sealing and / or reinforcing cavities in a vehicle using sealing / reinforcing components.

Description

Technical Field

[0001] This invention relates to a method for sealing and / or reinforcing cavities in a vehicle using sealing / reinforcing components. Background Technology

[0002] It is known in the prior art to use sealing / reinforcing components to seal and / or reinforce cavities in vehicles. The sealing / reinforcing components are inserted into the cavities and subsequently foamed. However, each sealing / reinforcing component must be customized for a specific application, and its design requires significant time. Summary of the Invention

[0003] Therefore, the object of the present invention is to improve the method of sealing and / or reinforcing cavities in a vehicle using sealing / reinforcing components.

[0004] This objective is achieved by a method for designing cavities in a vehicle, the cavity including sidewalls and defining the location of a sealing / reinforcing component within the designed cavity, and using an expandable sealing / reinforcing component to seal and / or reinforce the defined cavity, the method comprising the following steps:

[0005] a. Determine the cross-section of the cavity.

[0006] b. Determine the orientation of the axial extension of the cavity.

[0007] c. Based on the data from steps a to b, select sealing / reinforcement components from a predetermined dataset.

[0008] d. Determine the axial extension of the cavity without any holes in the sidewalls.

[0009] e. Place the sealing / reinforcing component into the designed cavity (1) and

[0010] f. To expand the sealing / reinforcing components.

[0011] This invention relates to a method for sealing and / or reinforcing cavities in a vehicle. The cavity, including sidewalls, is preferably part of the vehicle's frame, such as A-pillars, B-pillars, and / or C-pillars, and / or part of the vehicle's top and / or bottom frames. Other applications of the cavity may be as a vehicle's crossbeam or fairing, or it may be part of a passageway, such as a transmission tunnel. The cavity is preferably part of the body-in-white. Sealing protects the cavity, for example, from moisture and / or dust and / or reduces noise. Reinforcement provides greater stability to the cavity. The cross-section of the cavity where the sealing / reinforcing components are placed is preferably square, rectangular, circular, and / or elliptical. More than one sealing / reinforcing component may be placed in a cavity. The sealing / reinforcing components may be the same or different in material and / or shape. The sealing / reinforcing components may be arranged parallel to each other or at an angle relative to each other.

[0012] The sealing / reinforcing component is disposed in the cavity in its unexpanded state. The sealing / reinforcing component is preferably secured in the cavity, for example, by welding or clamping, such as using a push pin. The sealing / reinforcing component, along with the cavity, can then be placed in a furnace or the like, where the thermally expandable material can be heated and expand once a certain activation temperature is reached. The cavity is sealed and / or reinforced due to the expansion. Those skilled in the art will understand that energy for increasing the temperature of the expandable material can be provided in other ways, such as microwave radiation, radio frequency radiation, and / or infrared radiation.

[0013] The sealing / reinforcing component may include a carrier, which may comprise a rigid polymer material. The carrier may include a flat metal sheet. The carrier may include aluminum. The carrier may be a metal stamping. The carrier may also comprise a mesh material. The carrier may comprise a variety of other materials, such as polymers, elastomers, fibrous materials (e.g., fabrics or braided materials), thermoplastics, plastics, nylon, and combinations thereof. The carrier may be flexible, allowing the reinforcing component to bend to conform to the curves of the sheet material structure.

[0014] The sealing / reinforcing assembly also includes a heat-expandable activating material. Those skilled in the art will understand that the invention also covers other mechanisms for expanding the activating material. After the sealing / reinforcing assembly is placed into the cavity and the cavity is heated, the activating material expands, flows, cures, or some combination thereof according to a predetermined set of conditions. For example, exposure to a certain degree of heat causes the activating material to expand. The volumetric expansion of the activating material can vary depending on the sealing / reinforcing needs of a specific area, such as a sheet material. The activating material can expand by at least about 100% compared to its unexpanded state (green state). The activating material can expand by less than about 2000%. The activating material can expand by at least about 500%, at least about 1000%, or more. The activating material can expand by less than about 1000% or even less than about 500%.

[0015] The activatable material can be resinous, typically feeling dry or sticky to the touch, and can be formed into any desired pattern, placement, or thickness, but preferably has a substantially uniform thickness. However, it is preferable that the activatable material is plate-shaped, with a thickness less than the length and width of the plate. While other thermally activating materials can be used for the activatable material, the preferred thermally activating material is an expandable polymer or plastic, and preferably foamable. The activatable material can have a preform viscosity, such that it resists flow prior to activation when located within multiple pores.

[0016] Activated materials can be thermosetting materials. Activated materials can cure at room temperature without additional stimulation. Activated materials can withstand induction curing, microwave curing, UV-activated curing, or moisture curing, any of which can occur at room temperature or at elevated temperatures. Activated materials can be cured via redox reaction curing systems. Activated materials can include two-component curing systems, wherein curing occurs when the two components are mixed. Typically, activated materials cure at temperatures ranging from about 15°C to about 40°C.

[0017] Activatable materials can be formed from other materials, provided that the selected material is activated by heat or otherwise by environmental conditions (e.g., humidity, pressure, time, etc.) and cured under conditions suitable for the selected application. One such material is the epoxy-based resin disclosed in U.S. Patent No. 6,131,897, the teachings of which are incorporated herein by reference. Some other possible materials include, but are not limited to, polyolefin materials, copolymers and terpolymers having at least one monomer type of α-olefin, phenol / formaldehyde materials, phenoxy materials, and polyurethane materials having a high glass transition temperature. Other materials may also be used, such as those disclosed in U.S. Patent Nos. 5,766,719, 5,755,486, 5,575,526, and 5,932,680, which are incorporated herein by reference for various considerations. A preferred activatable material is the product sold by the applicant under the name L-2820.

[0018] In applications where the activating material is thermally activated, an important consideration in material selection and formulation is the material's curing temperature, and if it is expandable, the expansion temperature. Generally, when a material is treated with the vehicle structure at elevated temperatures or with higher levels of applied energy, such as during the curing steps of a coating process (e.g., electrophoretic coating, paint, or varnish), the material becomes reactive (cured, expanded, or both) at higher processing temperatures, such as those experienced in vehicle assembly plants. Temperatures experienced during vehicle assembly operations can range from about 148.89°C to 204.44°C (about 300°F to 400°F) for body shop applications (e.g., electrophoretic coating), while for paint shop applications they are typically about 93.33°C (about 200°F) or slightly higher (e.g., 120°C to 150°C).

[0019] Preferably, the carrier and the activatable material are co-extruded.

[0020] In the first step (step a), the cross-section of the cavity to be sealed and / or reinforced is determined, preferably the shape and size of the cross-section. If the cross-section is substantially rectangular, the width and height of the cavity at the location where the sealing / reinforcing component is placed are determined, for example, by measurement. If the cross-section of the cavity changes with its axial extension, an average shape and / or average size are preferably determined.

[0021] Furthermore, in step b, the orientation of the axial extension of the cavity to be sealed and / or reinforced relative to gravity is determined. Axial extension is the direction perpendicular to its cross-section or the extension of the cavity in its longitudinal direction. Generally, the axial extension of the cavity is significantly greater than the cross-sectional extension. Preferably, three types can be selected: horizontal, inclined, and vertical, wherein "horizontal" is at a substantially 90° angle relative to gravity, "inclined" is preferably at an angle >20° and <80° relative to the horizontal plane, preferably 40° to 60°, and "vertical" is preferably substantially parallel to gravity.

[0022] In the next step (step c), an expandable sealing / reinforcing component is selected based on the data from steps a to c. Preferably, a table is provided that includes the dimensions of the cavity's cross-section and the cavity's orientation. Expandable sealing / reinforcing components are recommended based on these input parameters. The data provided in the table is specific to a particular activatable material, such as L-2820. The data is also preferably specific to a particular expansion temperature range. This table may be provided electronically. The data stored in the table may be obtained experimentally and / or electronically.

[0023] For the recommended expandable sealing / reinforcing assembly, data regarding the maximum expansion length is preferably available, indicating the expansion length along the length direction of the cavity. The length direction is perpendicular to the cross-section of the cavity. This expansion length is important, for example, to prevent activated expanding material from blocking openings in the cavity, such as screw holes, required to secure the component to the cavity. Therefore, the maximum expansion length will guide the positioning of the expandable sealing / reinforcing assembly so that the openings are not blocked by expanding material. The maximum expansion length can also be used to design the cavity, particularly to design the position of one or more openings in the sidewalls of the cavity. These openings are preferably positioned such that each opening is outside the maximum expansion length, thereby preventing them from being blocked by expanding material. Preferably, the acceptable and / or desired maximum expansion length is measured starting from the location where the expandable sealing / reinforcing assembly is secured to the cavity.

[0024] According to a preferred embodiment of the invention, the sealing / reinforcing component is fixed at a fixed location within the cavity, preferably at the geometric center of the cross-section. Preferably, the geometric center or center of gravity of the expandable material coincides with the geometric center of the cross-section at the fixed location of the cavity before expansion. According to another preferred embodiment of the invention, the center of the cross-section of the cavity at the fixed location coincides with the center of the cross-section of the sealing / reinforcing component.

[0025] Preferably, the acceptable maximum expansion length is divided into two sub-lengths, one extending in one direction relative to a fixed point in the cavity, and the other extending in the opposite direction relative to the fixed point in the cavity. More preferably, the two sub-lengths are different.

[0026] According to a preferred embodiment of the invention, the sealing / reinforcing component is fixed in a fixed location within the cavity, preferably at the center of the cross-section. The sealing / reinforcing component may be welded or clamped into the cavity.

[0027] Preferably, the center of the cavity's cross-section coincides with the center of the sealing / reinforcing component's cross-section.

[0028] As described above, the sealing / reinforcement components are selected based on a dataset. Preferably, especially when the cavity has a square or rectangular cross-section, the dataset includes data on the width and height of the cavity's cross-section.

[0029] The expected expansion length is divided into two sub-lengths, both preferably measured from the axial center of the sealing / reinforcing assembly and / or the fixing point of the sealing / reinforcing assembly in the cavity. Preferably, the sub-lengths are different. Preferably, no holes are provided in the sidewalls of the cavity within this expansion length to avoid clogging of the holes by the expansion material.

[0030] The expandable component can be any component known to a skilled artesian. Preferably, the component is a thermally expandable component disposed on a carrier. The carrier and the expandable component can be co-extruded and / or over-molded and / or thermally welded and / or thermally bonded.

[0031] Preferably, the expandable material is a thermally expandable material. Preferably, the thermally expandable material expands in a furnace, which preferably dries the body-in-white. However, the invention also covers other methods of expanding the components. Expansion may, but does not necessarily, take place in a furnace.

[0032] Preferably, the dataset relates to conditions affecting the expansion rate, such as temperature during expansion and / or energy transferred to the sealing / reinforcing components, more preferably the temperature in the furnace in which the body-in-white is cured. Attached Figure Description

[0033] The invention will now be explained with reference to the accompanying drawings. These explanations do not limit the scope of protection.

[0034] Figure 1 a) through c) describe three implementations of the sealing / reinforcing components in the cavity.

[0035] Figure 2Details of the cavity and sealing / reinforcement components are shown.

[0036] Figures 3a to 3c Cavities with different spatial orientations are depicted.

[0037] Figure 4 and Figure 5 Predetermined data were used to depict cavities with different orientations.

[0038] Figure 6 A design guidance scheme was described. Detailed Implementation

[0039] Figure 1 a) and b) respectively illustrate embodiments of a cavity 1 having an internal sealing / reinforcing component 2. The sealing / reinforcing component, in the present case, comprises a carrier 4 and a thermally expandable material 5. The carrier is not a mandatory feature of the invention, but a preferred feature. The cavity, in the present case, comprises two parts connected together at a flange in this embodiment. In the present case, the cross-section of the cavity is rectangular, but those skilled in the art will understand that the cross-section can have any shape and / or any size. Typical shapes of the cross-section are rectangular, square, circular, and / or elliptical. The shape of the cavity can change with its axial direction, which in this case is perpendicular to the plane of the paper. The cavity is a part of the body-in-white of a transport vehicle, preferably a vehicle. Figure 1 In embodiment a), the carrier 4 is welded (in this case, spot-welded) to the cavity (in this case, the flange of the cavity). According to... Figure 1 In embodiment b), the sealing / reinforcing component 2 is fixed to the cavity by welding or by means of a clamp (here, a push-fit). Figure 1 As depicted in b), the carrier can be straight or curved. In the embodiment according to both figures, the geometric center of the cross-section of the expandable material and the geometric center of the cavity cross-section are the same. This is a preferred embodiment of the invention, but not a mandatory one. Figure 1 c) describes an embodiment in which the carrier is clamped into the cavity. See also, in other respects, according to Figure 1 The implementation methods of a) and b).

[0040] Figure 2 Details of the cavity 1 and the expandable material 5 inside are shown. The carrier is omitted in this and the following figures for simplicity. According to the invention, the shape and size of the cross-section must be shown. In the present case, the cross-section in which the expandable material is placed is rectangular in shape and has dimensions SL*SH. In the present case, the expandable material also has a rectangular cross-section with dimensions EL*EH. The geometric centers of the two cross-sections coincide in the present case.

[0041] Figures 3a to 3c Three different orientations of cavity 1 are shown. Figures 3a to 3c All of this describes the axial extension of cavities and expandable materials. Based on... Figure 3a In this embodiment, the spatial orientation of the cavity and the axial extension of the expandable material is horizontal. The axial fixing location of the expandable material is indicated by reference numeral 8 and the dashed line. In the present case, the expandable material is fixed at its axial center, which is the preferred embodiment. Figure 3a The cavity is also depicted having at least one hole 7, in this case four holes 7, which are used, for example, to attach a (not depicted) portion to the cavity 1. The distances from the fixing point to the holes 7 are D1 and D2, respectively. Since it is not desirable for the holes to be closed by the expanded material or even for the expanded material to flow out of the holes 7, the length (D1+D2) is the maximum acceptable expansion length. Figure 3a The expanded material 6 and its axial extensions L1 and L2 are also depicted. It can be seen that L1 is smaller than D1 and L2 is smaller than D2, therefore the hole 7 is not closed by the expanded material. According to... Figure 3a In this implementation, L1 and L2 are expected to be substantially the same. The acceptable maximum expansion length D1+D2 is preferably a result of the method of the present invention, and its dimensions are set such that it is greater than L1+L2. The axial position of the expandable material, here position 8, is also a result of the method of the present invention.

[0042] Figure 3b and Figure 3c The principle is shown according to Figure 3a The implementation method is as described above, therefore, reference can be made to the above disclosure. However, according to... Figure 3b In one embodiment, the axial extension of cavity 1 is inclined, forming an angle of approximately 45° relative to the horizontal plane, while according to... Figure 3c In this embodiment, the axial extension of the cavity is oriented vertically or parallel to the direction of gravity. According to... Figure 3b and Figure 3c In this embodiment, length L2 is less than L1, although this differs from what is depicted. The spatial orientation of the axial direction of cavity 1 is an input parameter for the method of this invention.

[0043] To perform the method of this invention, data on the expansion characteristics of a specific expandable material must be obtained, which depend on the shape and size of the expandable material, and also on the shape and size of the cross-section of the cavity in which the expandable material is placed. Data on different orientations of the axial extension of the cavity can be obtained. The data may be related to temperature-time curves and / or temperature during expansion. The data can be obtained experimentally or computationally. The data is preferably stored in a computer database. The expandable portion is positioned at the center of the cross-section of the cavity. The extension of the expandable portion in the axial direction EL is parallel to the axial extension of the cavity. Figure 4 Data for vertically oriented cavities with rectangular or square cross-sections are shown. Starting from the left side of the table, the first column shows the width and height of the cavity's cross-section. The next three columns specify the dimensions of the expandable portion in its unexpanded state, where EI and EH indicate the cross-section of the expandable material and EL indicates its length in the direction parallel to the cavity's length axis. The last three columns show the length of the expanded material. Except for the last two rows, the cavity's cross-section, SH*SL, is always completely enclosed by the expanded material. Lmax indicates the maximum expansion length, L1max is the expansion length in one direction extending axially into the cavity, and L2max is the expansion length in the opposite direction. L2 is expansion against gravity, while L1 is expansion in the direction of gravity. This table is fundamental for selecting a suitable expandable material, especially its shape and size, to completely and along the desired expansion length of the cavity's cross-section. The table can also provide guidance for locating holes in the cavity, especially for dimensions D1 and / or D2.

[0044] for Figure 5 In other words, it can be referred to as targeting Figure 4 The publicly available information, except that the cavity is not vertical in its current state but tilted at a 45° angle, is as shown in the figure.

[0045] According to Figure 6 The method of the present invention will be explained. It is assumed that a cavity with a cross-section of SL*SH=50*50 will be filled with an expanding material. The axial extension of the cavity is horizontal. This information is inserted according to... Figure 6 The table provides a selection of an expandable material of 35×10×35. This expandable material can be placed at the center of the cavity's cross-section. From the table, those skilled in the art can also deduce that the expected expansion lengths L1+L2 are both 70mm. Therefore, if holes 7 are required in the cavity wall around the expandable material, they should be located 80mm away from the center of the expandable material, since both D1 and D2 are 80mm.

[0046] List of reference numerals

[0047]

Claims

1. A method for designing a cavity (1) for a vehicle, the cavity including sidewalls and defining the position of a sealing / reinforcing assembly (2) within the designed cavity, and using an expandable sealing / reinforcing assembly (2) to seal and / or reinforce the defined cavity (1), the method comprising the steps of: a. Determine the cross-section of the cavity (1). b. Determine the orientation of the axial extension of the cavity. c. Select the sealing / reinforcing component (2) from a predetermined dataset based on the data from steps a to b. d. Determine the axial extension length of the cavity without any holes for the selected expandable sealing / reinforcing assembly, the length being the acceptable maximum expansion length of the sealing / reinforcing assembly (2). e. Place the sealing / reinforcing assembly into the designed cavity (1) and f. Inflate the sealing / reinforcing component.

2. The method according to claim 1, characterized in that, The sealing / reinforcing component (2) is fixed at a fixed location (3) in the cavity.

3. The method according to claim 2, characterized in that, The sealing / reinforcing component (2) is fixed at the center of the cross section.

4. The method according to any one of claims 1 to 3, characterized in that, The center of the cross-section of the cavity coincides with the center of the cross-section of the sealing / reinforcing assembly.

5. The method according to any one of claims 1 to 3, characterized in that, The dataset includes data on the width (SL) and height (SH) of the cross section of the cavity (1).

6. The method according to any one of claims 1 to 3, characterized in that, The expected expansion length is divided into two sub-lengths (L1, L2).

7. The method according to claim 6, characterized in that, The sub-lengths (L1, L2) are different.

8. The method according to any one of claims 1 to 3, characterized in that, The expandable components are mounted on the carrier (4).

9. The method according to claim 8, characterized in that, The carrier (4) and the expandable components are co-extruded and / or overmolded and / or thermally welded and / or thermally bonded.

10. The method according to any one of claims 1 to 3, characterized in that, Expandable materials expand due to energy input.

11. The method according to claim 10, characterized in that, The energy referred to is thermal energy.

12. The method according to claim 10, characterized in that, The energy referred to is energy from the furnace.

13. The method according to claim 10, characterized in that, The dataset represents the correlation conditions that affect the expansion rate of expandable components.

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