JP4514567B2 - Automotive panel structure - Google Patents

Description

  The present invention relates to a panel structure such as a dash panel portion or a floor portion that partitions an engine room and a vehicle compartment of an automobile.

  In general, a dash panel portion that partitions an engine room and a vehicle compartment of an automobile and a floor portion that forms the lower surface of the vehicle compartment are formed by a dash panel or a floor panel made of a flat steel plate. Panels such as the dash panel and floor panel that separate the interior of the vehicle interior and the exterior from the engine sound and vibration transmission sound such as road noise transmitted from the tire via the suspension and the vehicle body frame and radiated into the vehicle interior are transmitted. Soundproofing material is installed to suppress sound.

  The soundproofing material attached to the panel such as the floor panel and the dash panel is composed of a two-layer structure in which a sound insulating material such as urethane, felt, or PET material is laminated on the surface with a sound insulating material such as rubber or vinyl chloride sheet. In addition, a sound insulation structure is known in which a three-layer structure of a panel, a sound absorbing material, and a sound insulation material is provided by mounting the sound insulation material on a floor panel or a dash panel.

  In addition, the surface of a sound absorbing material made of a molded body formed from fiber waste generated in the yarn production or spinning process and a binder that binds the fiber waste as a raw material has a relatively high surface density such as recycled rubber and recycled vinyl chloride sheet. A sound insulation structure is known in which a sound insulation material is formed by a two-layer structure in which sound insulation materials are laminated, and the sound insulation material is attached to a floor panel or a dash panel to form a three-layer structure of the panel, the sound absorption material, and the sound insulation material. (For example, refer to Patent Document 1).

  In addition, a pair of curved surfaces with a long oval shape in the longitudinal direction of the vehicle body and bulging downward on the floor panel that is long in the longitudinal direction of the vehicle body are arranged in the longitudinal direction of the vehicle body. The vehicle is designed to vibrate in the 2 × 1 mode that produces one antinode in the width direction, and to reduce road noise by reducing the sound emitted from the floor panel so that its natural frequency is 220 to 240 Hz. A floor structure is known (see, for example, Patent Document 2).

Furthermore, it is also known that the floor panel itself has a plurality of curved spherical or pan-bottom curved portions, thereby increasing the resonance frequency by increasing the rigidity of the floor panel itself and suppressing vibration transmission sound during traveling. (For example, see Patent Document 3 and Patent Document 4)
JP 2003-201658 A JP 2004-50913 A JP 59-145458 A See JP 2000-238668 A

  According to the above-mentioned patent document 1, the dash panel or floor part is made of a dash panel or a three-layer sound insulation structure of the floor panel, a sound absorbing material and a sound insulating material, and the density of the fiber material and the sound absorbing material forming the sound absorbing material is adjusted. Thus, the sound absorption performance and sound insulation performance can be improved.

  Here, the panel structure, such as the dash panel and floor part, which is constructed in a three-layer structure with the sound absorbing material as the intermediate layer and the panel of the dash panel or floor panel and the sound insulating material, Transmission loss greater than the mass rule can be obtained. Here, the transmission loss TL (dB) based on the mass rule is expressed by the following equation using the surface density M and the frequency f of the material.

TL = 18 logf · M-44
That is, the transmission loss TL based on the mass rule is proportional to the product of the surface density M (kg / m ² ) of the material and the frequency f (Hz).

  In a typical three-layer sound insulation structure used in automobiles, as shown in FIG. 5, there is a drop in the first transmission loss at the first-order resonance frequency of the panel, followed by a low-frequency resonance transmission frequency from 200 to 300 Hz. There is a frequency band called transmission loss reduction, and a sound insulation effect that greatly exceeds the mass law occurs in a frequency band of 500 Hz or higher. However, since the peak of in-vehicle noise such as engine sound and road noise has a frequency of 200 to 300 Hz, the three-layer sound insulation structure of the panel, the sound absorbing material, and the sound insulating material reduces the transmitted sound such as engine sound and road noise. Cannot be achieved.

  Further, according to Patent Document 2, the acoustic radiation efficiency is lowered due to the occurrence of 2 × 1 mode vibration in which two elliptical curved surface portions adjacent in the longitudinal direction of the vehicle body vibrate in opposite phases and with the same amplitude. Can reduce road noise.

  However, there is a concern that the entire floor panel is elastically deformed while the automobile is running, and sufficient transmission loss cannot be obtained, and the transmitted sound transmitted through the floor panel due to engine sound, road noise, or the like cannot be sufficiently reduced.

  Similarly, in Patent Document 3 and Patent Document 4, although the rigidity of the floor panel is improved, the entire floor panel is elastically deformed while the vehicle is running, and sufficient transmission loss cannot be obtained. There is a possibility that the transmitted sound cannot be reduced sufficiently.

  Here, as a result of intensive studies and experiments, the inventors have found that the characteristics of road noise decrease at a substantially constant rate after the frequency reaches a peak around 300 Hz, and the transmission loss increases as the panel rigidity increases. Focusing on the fact that the frequency range in which the noise is improved is mainly in the 200 to 300 Hz band, it was found that the transmitted sound due to engine noise and road noise can be reduced by increasing the rigidity of the panel.

  Accordingly, an object of the present invention made in view of such a point is to provide an automobile panel structure having excellent sound insulation performance by increasing the primary resonance frequency of the panel and improving transmission loss in a frequency band of 200 to 300 Hz. There is to do.

The invention of an automotive panel structure according to claim 1, which achieves the above object, is provided in the automotive panel structure, wherein the panel is attached to a vehicle body member formed on an outer periphery of the panel ; On the other hand, a pair of curved surface portions that bulge outwardly from the passenger compartment in a substantially spherical shape and are formed in a substantially rectangular shape in plan view are disposed extending between the curved surface portions , and end portions separate the curved surface portions from each other. And a bead projecting toward the vehicle interior side with respect to the mounting surface, with both lower end edges connected to the edges of the curved surface portions .

  According to a second aspect of the present invention, in the automobile panel structure according to the first aspect, the curved surfaces are formed in a substantially rectangular shape having a pair of long sides opposed to each other in plan view and a pair of opposed short sides. The maximum protrusion amount with respect to the mounting surface of the part is 1/20 or more of the length of the long side, and the protrusion amount of the bead is 1/20 or more of the length of the long side.

  According to a third aspect of the present invention, in the automobile panel structure of the second aspect, the curved surface portion is a circle having a cross-sectional shape parallel to the long side passing through the center of the curved surface portion in plan view and having the same radius over the entire range. It is arcuate and the cross-sectional shape parallel to the short side passing through the center is an arc having the same radius over the entire range.

  The invention according to claim 4 is the panel structure of the automobile according to claim 1, wherein the panel structure is laminated on the vehicle interior side of the panel and absorbs sound transmitted through the panel, and the sound absorbing material. A sound insulation material that is laminated on the vehicle interior side surface and blocks the sound transmitted through the panel and radiated into the vehicle interior, and the panel has a low-frequency resonance transmission frequency at which the panel and the sound insulation material resonate. It has a higher primary resonance frequency.

According to the invention of claim 1, in the panel structure of an automobile, a pair of curved surface portions formed in a substantially rectangular shape in plan view that swells in a spherical shape adjacent to a panel having an attachment surface whose outer periphery is attached to a vehicle body member. The panel is formed to increase the rigidity of the panel. Further, the end portions are connected to the mounting surfaces facing each other across the curved surface portions, and the lower end edges are connected to the edges of the curved surface portions, respectively, and the vehicle interior to the mounting surface. By forming the bead protruding inward, the rigidity of the panel is improved, and the primary resonance frequency of the panel can be increased. By increasing the primary resonance frequency, transmission loss is improved in the frequency band of 200 to 300 Hz, engine noise and road noise are reduced, and an automobile panel structure with excellent sound absorption and sound insulation performance is secured. it can.

  The invention of claim 2 more specifically limits the curved surface portion and the bead of claim 1, and sets the maximum protrusion amount of the curved surface portion with respect to the mounting surface to 1/20 or more of the length of the long side. By setting the protruding amount of the bead to 1/20 or more of the length of the long side, the effect of claim 1 can be obtained with certainty.

  According to the invention of claim 3, the shape of the curved surface portion is set to an arc shape having a cross section parallel to the long side passing through the center of the curved surface portion in plan view and having the same radius over the entire range, and the short side passing through the center By setting the cross-sectional shape in parallel with the circular arc shape having the same radius over the entire range, the rigidity of the curved surface portion can be improved more efficiently.

  According to the invention of claim 4, the sound absorbing material laminated on the vehicle interior side of the panel and absorbing the sound transmitted through the panel, and the sound absorbing material laminated on the vehicle interior side surface of the sound absorbing material and transmitted through the panel into the vehicle interior. And a panel having a primary resonance frequency that is higher than a low-frequency resonance transmission frequency at which the panel and the sound insulation material resonate, thereby improving transmission loss. And road noise can be reduced, and an automobile panel structure excellent in sound absorption and sound insulation performance can be secured.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of an automobile panel structure according to the present invention will be described below with reference to the drawings, taking an automobile floor as an example.

  1 is a perspective view showing an outline of a floor panel 1 forming a floor portion of an automobile, FIG. 2 is a cross-sectional view taken along line II in FIG. 1, and FIG. 2 is a cross-sectional view taken along line II-II in FIG. .

  As shown in FIG. 1, the floor panel 1 is a substantially rectangular panel, and is formed of a substantially rectangular steel plate having a mounting surface 2 that joins the floor panel 1 to a vehicle body member on the outer periphery thereof.

  The mounting surface 2 formed on the outer periphery of the floor panel 1 includes a first mounting surface portion 3 and a second mounting surface that are coupled to a vehicle body member such as a tunnel portion, a frame, and a side sill (not shown) extending in the longitudinal direction of the vehicle body. A vehicle body member such as a cross member that extends along the front edge of the portion 4 and extends in the vehicle body width direction with each end continuing to the front end of each of the first mounting surface portion 3 and the second mounting surface portion 4. A third mounting surface portion 5 coupled to the rear edge, and each end extends along the rear edge and is continuous with each rear end of the first mounting surface portion 3 and the second mounting surface portion 4 and in the vehicle body width direction. It is formed by the 4th mounting surface part 6 couple | bonded with vehicle body members, such as the extending cross member. The mounting surface 2 is coupled to the vehicle body member by spot welding or continuous welding, and the entire circumference is constrained.

  A bead 11 extending between the first mounting surface portion 3 and the second mounting surface portion 4 disposed so as to face each other and having an end portion connected to an intermediate portion in the front-rear direction is spanned. As shown in FIGS. 1 and 3, the bead 11 is flat and has a belt-like top surface portion 12 which continues in the vehicle width direction, and is bent along the front edge and the rear edge of the top surface portion 12, respectively. It is formed in a substantially U-shaped cross section that protrudes upward and consists of a front surface portion 13 and a rear surface portion 14 that are side surfaces that are separated from each other as the vehicle moves.

  The first curved surface portion 21 is formed on the inner edge 3a of the first mounting surface portion 3, the inner edge 4a of the second mounting surface portion 4, the inner edge 5a of the third mounting surface portion 5, and the lower end edge 13a of the front surface portion 13 of the bead 11, respectively. The side edges 21a and 21b that are the surrounding short sides, and the front edge 21c and the rear edge 21d that are the long sides are connected in a generally rectangular shape in plan view, and have a spherical shape or a pot-bottom shape that bulges downward to the outside of the passenger compartment. It is formed in a concave shape.

  The second curved surface portion 22 is formed on the inner edge 3 a of the first mounting surface portion 3, the inner edge 4 a of the second mounting surface portion 4, the lower end edge 14 a of the rear surface portion 14 of the bead 11, and the inner edge 6 a of the fourth mounting surface portion 6. Each of the side edges 22a and 22b which are short sides and the front edge 22c and the rear edge 22d which are long sides are connected to each other in a substantially rectangular shape in plan view, and a spherical shape or a pot bottom shape which bulges downwardly outside the passenger compartment. It is formed in the concave shape.

As shown in FIG. 2, the cross-sectional shape along the vehicle width direction at the center of the first curved surface portion 21 in the longitudinal direction of the vehicle body, that is, the cross section passing through the center of the inner edge 21a and the outer edge 21b in FIG. It is formed in an arc shape with the same radius R ₁ and a constant curvature. Further, as shown in FIG. 3, the cross-sectional shape along the vehicle longitudinal direction at the center in the vehicle width direction, that is, the cross section passing through the center of the front edge 21c and the rear edge 21d has the same radius R _{2 over the} entire range. And is formed in an arc shape with a constant curvature. Thus, the rigidity of the 1st curved-surface part 21 can be efficiently improved by forming the cross-sectional shape which passes along the center of the 1st curved-surface part 21 in circular arc shape of the same radius.

  Further, in the first curved surface portion 21, the protrusion amount H with respect to the mounting surface 2 is set to be 1/20 or more of the length La of the front edge 21c and the rear edge 21d having long sides.

Similarly to the first curved surface portion 21, the second curved surface portion 22 is formed in an arc shape having a constant radius of curvature R ₁ and a constant curvature along the vehicle width direction at the center in the vehicle longitudinal direction. The cross-sectional shape along the longitudinal direction of the vehicle body at the center of the direction is formed in an arc shape having the same radius R ₂ and a constant curvature, and thus the cross-sectional shape passing through the center of the second curved surface portion 22 is formed in a constant arc shape. By doing so, the rigidity of the second curved surface portion 22 can be efficiently increased. Further, the maximum protrusion amount H with respect to the mounting surface 2 is set to 1/20 or more of the length La of the front edge 22c and the rear edge 22d which are long sides.

  On the other hand, a first mounting surface portion 3 that is arranged to extend between the first curved surface portion 21 and the second curved surface portion 22 and whose end portions face each other with the first curved surface portion 21 and the second curved surface portion 22 therebetween. The protruding amount h of the bead 11 connected to the second mounting portion 4 and continuously protruding toward the vehicle interior side with respect to the mounting surface 2 is the front edges 21c and 22c, which are the long sides of the first curved surface portion 21 and the second curved surface 22, and the rear. It is set to 1/20 or more of the length La of the edges 21d and 22d.

  By setting the protrusion amount H of the first curved surface portion 21 and the second curved surface portion 22 to be 1/20 or more of the long side length La, deformation of the first curved surface portion 21 and the second curved surface portion 22 is prevented or Further, by setting the protruding amount h of the bead 11 to 1/20 or more of the long side length La, the rigidity of the floor panel 1 is improved, the resonance frequency is increased, and the vibration damping performance can be improved.

  As shown in FIG. 4, the floor panel 1 is transmitted through the upper surfaces of the first curved surface portion 21 and the second curved surface portion 22 of the floor panel 1 thus formed up to the height of the top surface portion 12 of the bead 11. Then, a sound absorbing material 31 made of urethane, felt, PET material or the like that absorbs the sound radiated into the passenger compartment is laminated.

  Further, comparison is made between a rubber sheet, a vinyl chloride sheet, and the like that block the sound emitted through the floor panel 1 and the sound absorbing material 31 to the vehicle interior side over the surface of the sound absorbing material 31 and the top surface portion 12 of the bead 11. A sound insulating material 32 having a high surface density is laminated and integrated.

  In this way, the sound insulating material 32 is laminated and integrated on the floor panel 1 via the sound absorbing material 31, and the top surface, that is, the vehicle interior side is flat in a three-layer structure of the floor panel 1, the sound absorbing material 31, and the sound insulating material 32, so-called sandwich structure. Form the floor.

  The floor portion configured as described above can improve the rigidity of the floor panel 1, and by greatly increasing the primary resonance frequency of the floor panel 1, the frequency at which the peak of in-vehicle noise such as engine sound and road noise is increased to 200. Transmission loss in a band of ˜300 Hz can be improved, and quietness in the passenger compartment can be ensured.

  FIG. 5 shows the frequency in a conventional floor structure composed only of a flat panel made of a steel plate having a thickness of 0.7 mm and a floor structure in which a sound absorbing material and a sound insulating material having a thickness of 20 mm are laminated on the flat floor panel. It is a figure which shows the correlation of transmission loss. The low frequency resonance transmission frequency by the floor panel and the sound insulating material is set in a range of 200 to 250 Hz.

  As is apparent from FIG. 5, in the floor structure composed of only the floor panel, the primary resonance frequency is around 200 Hz, and in the floor structure in which the sound absorbing material and the sound insulating material are laminated on the floor panel, the primary resonance is similarly applied. The frequency is in the band around 200 Hz. In these, the low frequency resonance transmission frequency overlaps with a low frequency resonance transmission frequency in a band of 200 to 250 Hz where the peak frequency of engine noise and road noise during traveling is 20 dB or less, and sufficient transmission loss cannot be obtained in this band. I can confirm that.

  FIG. 6 shows the frequency and transmission loss in the conventional floor structure made of only a flat panel and a floor panel made of a steel plate having a thickness of 0.7 mm, and the floor structure made only of the floor panel in this embodiment shown in FIGS. It is a figure which shows these relative relationships.

The floor panel 1 in the present embodiment has a first curved surface portion 21 and a second curved surface portion 22 having a thickness t of 0.7 mm, a long side length La of 400 mm, and a short side length Lb of 220 mm. The length L from the front edge 21c of the first curved surface portion 21 to the rear edge 22d of the second curved surface portion 22 is 500 mm. The mounting surface 2 has an arc radius R ₁ parallel to the short side passing through the center of the first curved surface portion 21 and the second curved surface portion 22 of 1010 mm, and an arc-shaped radius R ₂ parallel to the long side passing through the center is 312.5 mm. The protrusion amount H of the first curved surface portion 21 and the second curved surface portion 22 is set to 1/20 with respect to the length La of the long side. In the bead 11, the width Wb of the top surface portion 12 is 40 mm, the protrusion amount h is 20 mm, and the protrusion amount h of the bead 11 is set to 1/20 with respect to the length La of the long side.

  From FIG. 6, the floor panel 1 in this embodiment has a primary resonance frequency in the vicinity of 500 Hz, and the protrusion amount H of the first curved surface portion 21 and the second curved surface portion 22 is 1/20 or more of the length L of the long side. In addition, by setting the protruding amount h of the bead 11 to 1/20 or more of the long side L, the primary resonance frequency of the floor panel 1 can be increased to 500 Hz as compared with the conventional floor panel, and the frequency is 200 It can be confirmed that the transmission loss is significantly improved in the band of ˜300 Hz.

  FIG. 7 shows a floor structure composed of only the floor panel 1 in the present embodiment, a sound absorbing material 31 made of felt having a thickness of 20 mm on the upper surface of the floor panel 1 and a rubber sheet on the surface of the sound absorbing material 31 as shown in FIG. It is a figure which shows the correlation of the frequency and transmission loss in the floor structure which laminated | stacked the sound insulating material 32 which consists of. The low frequency resonance transmission frequency by the floor panel and the sound insulating material is set in a range of 200 to 250 Hz.

  As is clear from FIG. 7, it is confirmed that the floor structure in which the sound absorbing material 31 and the sound insulating material 32 are laminated on the floor panel 1 has a higher transmission loss than the floor structure of only the floor panel 1 in the entire frequency range of 200 Hz or higher. it can.

  In the floor structure in which the sound absorbing material and the sound insulating material are laminated on the conventional floor panel, as is apparent from FIG. 5, the transmission loss is reduced in the frequency band of 200 to 250 Hz as compared with the floor structure having only the conventional floor panel. It can be confirmed that the transmission loss is not increased over the entire frequency range of 200 Hz or more as in the example. In this embodiment, the primary resonance frequency of the floor panel 1 is set to around 500 Hz, and the low-frequency resonance transmission frequency is set to around 200 to 250 Hz. Is performed from a frequency band of 200 Hz or less. Thereby, the transmission loss is efficiently improved in a frequency band of 200 to 300 Hz.

  In addition, it is good also as an equivalent value, without making the primary resonant frequency of the floor panel 1 and the low frequency range resonant transmission frequency into different values like the said embodiment. Even when the primary resonance frequency of the floor panel 1 and the resonance frequency of the sound insulating material 32 are made equal, the transmission loss in the floor panel 1 alone is improved, so that the engine sound and road noise can be sufficiently reduced. Can be planned.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the invention. For example, in the above embodiment, the sound absorbing material 31 is laminated to the same height as the top surface portion 12 of the bead 11 of the floor panel 1, and the sound insulating material 32 and the sound insulating material 32 are laminated on the surface of the top surface portion 12 to form a flat floor. Although the upper surface is secured in the section, as shown in the cross-sectional view corresponding to FIG. 4 in FIG. 8, sound absorption is performed over the entire surface of the floor panel 1 of the first curved surface portion 21, the second curved surface portion 22 and the bead portion 11 of the floor panel 1. Transmission loss can be improved by laminating the material 31 and further laminating the sound insulating material 32 on the surface of the sound absorbing material 31.

FIG. 9 is a diagram showing the correlation between frequency and transmission loss in each floor structure shown in FIGS. 4 and 8 of this embodiment and a floor structure in which a sound absorbing material and a sound insulating material are laminated on a conventional floor panel.
As is clear from FIG. 9, in any of the floor structures of FIGS. 4 and 8, the transmission loss in the frequency band of 200 to 300 Hz is improved by 20 dB or more compared to the conventional floor structure, and the engine sound and It can be confirmed that the road noise can be greatly reduced.

  Moreover, in the said embodiment, although demonstrated about the floor part of the motor vehicle as an example, it is also applicable to panel structures of other motor vehicles, such as a dash panel part.

It is a perspective view which shows the outline | summary of the floor panel which forms the floor part of the motor vehicle in embodiment of this invention. It is the II sectional view taken on the line of FIG. It is the II-II sectional view taken on the line of FIG. It is sectional drawing of a floor part. It is a figure which shows the correlation of the frequency and transmission loss in the floor part only of the conventional floor panel, and the floor part which laminated | stacked the sound-absorbing material and the sound insulation material on the conventional floor panel. It is a figure which shows the correlation of the frequency and transmission loss in the floor part only in the floor panel in a present Example, and the floor part which laminated | stacked the sound-absorbing material and the sound insulation material on the floor panel in an Example. It is a figure which shows the correlation of the frequency and transmission loss in the floor part only of the floor panel of a present Example, and the floor part only of the conventional floor panel. It is sectional drawing of the floor part of another motor vehicle of a present Example. It is a figure which shows the correlation of the frequency and transmission loss in the floor part which laminated | stacked the sound absorption material and the sound insulation material on the conventional floor panel, and the floor part shown to FIG. 4 and FIG.

Explanation of symbols

1 Floor panel (panel)
2 Mounting surface 3 First mounting surface portion 4 Second mounting surface portion 5 Third mounting surface portion 6 Fourth mounting surface portion 11 Bead 21 First curved surface portion 21a Inner edge (surrounding)
21b Outer edge (around)
21c Front edge (around)
21d Trailing edge (around)
22 2nd curved surface part 22a Inner edge (periphery)
22b Outer edge (around)
22c Front edge (around)
22d trailing edge (around)
31 Sound absorbing material 32 Sound insulating material

Claims (4)

In the panel structure of automobiles,
The above panel
An attachment surface attached to a vehicle body member formed on the outer periphery of the panel;
A pair of curved surfaces formed in a substantially spherical shape outwardly from the vehicle interior with respect to the mounting surface and formed in a substantially rectangular shape in plan view ;
It is arranged to extend between the two curved surface portions , the end portions are connected to the mounting surfaces facing each other across the two curved surface portions, the lower end edges are connected to the edges of the curved surface portions, and the mounting is performed. A panel structure for an automobile, comprising: a bead protruding toward the vehicle interior side with respect to the surface. The two curved surface portions are formed in a substantially rectangular shape having a pair of long sides facing each other in plan view and a pair of short sides facing each other, and the maximum protruding amount of the curved surface portion with respect to the mounting surface is 1/20 of the length of the long side. That's it,
The automobile panel structure according to claim 1, wherein the protruding amount of the bead is 1/20 or more of the length of the long side.   The curved surface portion has a cross-sectional shape parallel to the long side passing through the center of the curved surface portion in a plan view and an arc shape having the same radius over the entire range, and a cross-sectional shape parallel to the short side passing through the center is the entire range. The vehicle panel structure according to claim 2, wherein the vehicle has a circular arc shape with the same radius. The panel structure includes a sound absorbing material that is stacked on the vehicle interior side of the panel and absorbs sound transmitted through the panel, and a sound absorbing material that is stacked on the vehicle interior side surface of the sound absorbing material and passes through the panel to enter the vehicle interior. A sound insulating material that blocks the sound emitted;
The automobile panel structure according to claim 1, wherein the panel has a primary resonance frequency higher than a low-frequency resonance transmission frequency at which the panel and the sound insulating material resonate.

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