Title of invention: Panel member
Technical field
[0001]
(Cross reference to related applications)
　This application claims priority based on Japanese Patent Application No. 2018-172238 filed in Japan on September 14, 2018, and the contents thereof are incorporated herein.
[0002]
　The present invention relates to an automobile panel member.
Background technology
[0003]
　Automobile bodies are required to have improved collision performance and reduced weight. Collision performance is mainly ensured by members such as side members and side sills that constitute the frame of the vehicle body. In order to further improve the collision performance, there are methods such as increasing the thickness of the frame material and providing the frame with reinforcing members, but such methods are not preferable from the viewpoint of weight reduction. On the other hand, in order to improve collision performance, for example, a method of increasing resistance to collision in a panel member such as a floor panel connected to a side sill is also conceivable.
[0004]
　Patent Document 1 discloses a floor panel in which circular recesses are arranged in a floor panel main body in a honeycomb shape and the recesses are connected to each other by ribs. Patent Document 2 discloses a floor panel provided with a circular rigidity adjustment portion at the front portion in the vehicle length direction.
[0005]
　Also, US Pat. No. 6,201,303 discloses a composite modular energy absorbing assembly for effective energy absorption in various devices, for example, a configuration in which a plurality of circular recesses are arranged in parallel (Patent See Fig. 3, Fig. 11, etc. of Document 3).
prior art documents
patent literature
[0006]
Patent Document 1: JP-A-2017-061275
Patent Document 2: JP-A-2005-059817
Patent Document 3: JP-A-2005-514560
SUMMARY OF THE INVENTION
Problems to be Solved by the Invention
[0007]
　In the Small Over Lap test, which is a type of crash test, a load is input from the front of the side sill in the vehicle length direction, and a shear force is generated in the floor panel. As a result, out-of-plane deformation of the floor panel induces buckling in the shear direction (hereafter referred to as "shear buckling"), and if large shear buckling occurs in the floor panel at this time, crash performance is improved. The contribution of the floor panel in terms of
[0008]
　The floor panel of Patent Document 1 has recesses arranged in a honeycomb shape, so that large out-of-plane deformation is likely to occur in the oblique direction (direction between the vehicle length direction and the vehicle width direction), which contributes to the improvement of collision performance. There is room for improvement in this aspect.
[0009]
　The floor panel of Patent Document 2 aims at reducing noise caused by vibration of the floor panel without increasing the rigidity of the floor panel. In other words, the technique disclosed in Patent Document 2 contradicts the technique of increasing the rigidity of the floor panel to suppress the occurrence of large out-of-plane deformation.
[0010]
　The composite modular energy absorbing assembly described in US Pat. No. 5,300,000 is intended to be lighter and capable of absorbing greater impact energy at the shortest possible impact distance. In Patent Document 3, the ratio of the depth D to the diameter W (0.5 to 0.3), the ratio of the diameter W to the interval S between the recesses (0.2 to 0.2 to 0.3), and the configuration of the circular recesses. .7) is disclosed. Furthermore, it is disclosed that the side surface inclination angle α of the recess is 0 to 45 degrees. However, the composite modular energy absorbing assembly described in US Pat. Therefore, it cannot be said that this technology is suitable for panel members such as automobile floor panels, etc., which should ensure crashworthiness.
[0011]
　In addition, according to the studies of the present inventors, when forming a recess in a panel member of an automobile, the recess does not necessarily have to be circular, and more detailed configuration conditions such as the size, number, and arrangement of the recess are defined. Therefore, it is considered that there is room for further improvement in collision performance.
[0012]
　SUMMARY OF THE INVENTION It is an object of the present invention to improve the collision performance of an automobile panel member.
Means to solve problems
[0013]
　One aspect of the present invention for solving the above problem is provided with a plurality of circular or elliptical recesses arranged in a straight line, and when three of the recesses are arranged in a straight line is referred to as a recess group, at least the first one group of recesses and a second group of recesses arranged in parallel with the first group of recesses; An angle formed by a first straight line connecting the centers of the recesses in the second group of recesses and a second straight line connecting the centers of the recesses in the first group of recesses is 80 degrees or more and 100 degrees. degree or less, the recess comprises a bottom forming the bottom of the recess and sidewalls erected around the bottom, and an inclination angle ξ between the bottom and the sidewall is 20 degrees or more and 90 degrees or less. It is characterized by
Effect of the invention
[0014]
　The collision performance of the automobile panel member can be improved.
Brief description of the drawing
[0015]
1 is a diagram showing a schematic shape of a panel member according to an embodiment of the present invention; FIG.
2 is a diagram for explaining the arrangement of recesses in a panel member; FIG.
3 is a diagram showing an out-of-plane deformation occurrence portion (broken line portion) of the panel member with respect to the placement of the concave portion; FIG. Arrows in the figure indicate the direction of the shear force.
4 is a cross-sectional view of a panel member cut so as to include the centers of adjacent recesses; FIG.
5 is a diagram showing an arrangement example of recesses; FIG.
6 is a diagram showing the history of reaction force generated in the floor panel in a collision simulation of a comparative example; FIG.
7 is a diagram showing the history of the reaction force generated in the floor panel in the collision simulation of the example of the invention; FIG.
8 is a diagram showing the history of reaction force generated in the floor panel in a collision simulation of a comparative example; FIG.
9 is a diagram showing simulation results when the angle θ is changed. FIG.
10 is a diagram showing the relationship between the number of concave portions of the floor panel in the vehicle length direction and the reaction force generated in the floor panel in the vehicle width direction. FIG.
11] A diagram showing the relationship between the value of s/d and the maximum reaction force in the vehicle length direction. [FIG.
12 is a diagram showing the relationship between the tilt angle ξ and the maximum reaction force in the vehicle length direction. FIG.
13 is a diagram showing the relationship between the minor/major axis ratio b/a and the maximum reaction force in the vehicle length direction. FIG.
MODE FOR CARRYING OUT THE INVENTION
[0016]
　An embodiment of the present invention will be described below with reference to the drawings. In this specification and drawings, elements having substantially the same functional configuration are denoted by the same reference numerals, thereby omitting redundant description.
[0017]
　FIG. 1 is a diagram showing a schematic shape of a panel member 1 of this embodiment. In FIG. 1, the X direction is the vehicle length direction, the Y direction is the vehicle width direction, and the Z direction is the vehicle height direction, and the X, Y and Z directions are perpendicular to each other. As shown in FIG. 1, the panel member 1 of this embodiment has a plurality of recesses 10 provided along the X direction. The concave portion 10 has a circular shape in plan view. The concave portion 10 may have a concave shape when viewed from the inside of the vehicle of the panel member 1, or may have a concave shape when viewed from the outside of the vehicle. For example, when the panel member 1 is a floor panel, the recess 10 may have a recessed shape when viewed from above or a recessed shape when viewed from below. When the concave portion 10 has a concave shape when viewed from the inside of the vehicle, the concave portion 10 has a convex shape when viewed from the outside of the vehicle.
[0018]
　In the panel member 1 of the present embodiment, there are a portion where one row of recesses 10 arranged linearly is formed and a portion where two rows are formed. The arrangement of the rows of recesses 10 is not particularly limited, and may be changed as appropriate according to the required collision performance, the shape of the panel member 1 (the floor panel in this embodiment), and the like. Also, the length of the row of the recesses 10 is not particularly limited, and can be appropriately changed according to the required collision performance, the shape of the panel member 1 (the floor panel in this embodiment), and the like. However, when the panel member 1 is used as the floor panel of an automobile, from the viewpoint of improving the impact performance, it is preferable that the row of the concave portions 10 arranged in a straight line is arranged along the vehicle length direction of the automobile. .
[0019]
　The panel member 1 according to the present embodiment may be made of any material, but when used as a floor panel of an automobile, iron (including high-tensile strength materials), aluminum, CFRP, and the like are preferable.
[0020]
　FIG. 2 is an enlarged view of a portion where a plurality of rows of recesses 10 are arranged, and is a diagram for explaining the arrangement of the recesses 10 of the panel member 1 of this embodiment. In this specification, a portion of the panel member 1 in which three recesses 10 are arranged in a straight line is referred to as a "recess group G". When a plurality of groups of recesses G are arranged in parallel as shown in FIG . The group of recesses G arranged in parallel with the first group of recesses G 1 is called a “second group of recesses G 2 ”. In the example of FIG. 2, two rows of four concave portions 10 are shown . are also present along the X direction. From the viewpoint of improving collision performance, it is preferable that a plurality of the first recessed portion group G1 and the second recessed portion group G2 are provided as in the present embodiment.
[0021]
　Here, consider a case where an axial load is input to a side sill (not shown) to which the panel member 1 is joined. FIG. 3 is a diagram showing the occurrence of out-of-plane deformation with respect to the arrangement of the recessed portion 10 of the floor panel in that case. The dashed line in FIG. 3 indicates the out-of-plane deformation occurrence portion, and the arrow in FIG. 3 indicates the direction of the shear force. The conventional arrangement (a) is an example in which the concave portions 10 are arranged in a honeycomb pattern, and the conventional arrangement (b) is an example in which four concave portions 10 are arranged in a square shape.
[0022]
　When a shear force occurs as shown in FIG. 3, the panel member 1 in which the recess 10 is arranged is likely to undergo out-of-plane deformation along a direction (hereinafter referred to as "tilt direction") inclined with respect to the direction of the shear force. . Out-of-plane deformation occurs in a relatively weak portion of the panel member 1, but in the case of the conventional arrangement (a), the weak portion, that is, the portion where the recess 10 is not formed, is continuous in a wide area in the tilt direction. , and large out-of-plane deformation can occur along the tilt direction. If a large amount of shear buckling occurs due to this out-of-plane deformation, the contribution of the panel member 1 to the improvement of crashworthiness decreases. Also, in the case of the conventional arrangement (b), since there are still many portions with low rigidity in the tilt direction, the degree of contribution of the panel member 1 to the improvement of the collision performance is small.
[0023]
　On the other hand, in the arrangement of the concave portions 10 of the present embodiment, the first concave portion group G1 and the second concave portion group G2 are arranged in parallel, so that the low-rigidity portion is wide in the tilt direction. It is not continuous, and large out-of-plane deformation is less likely to occur. As a result, large shear buckling is less likely to occur in the panel member 1 at the time of collision, and it is possible to increase the resistance of the panel member 1 to the collision. As a result, the collision performance of the panel member 1 can be improved.
[0024]
< Positional Relationship Between First Group of Concavities G1 and Second Group of Concavities G2> In order for the panel member 1
　to function as described above, it is necessary to The positional relationship must satisfy a given condition. In this specification, in plan view as shown in FIG. 2, the center of an arbitrary recess 10 in the first recess group G 1 A straight line connecting the center of the concave portion 10 located at , is referred to as a "first straight line L 1 ". A straight line connecting the centers of the concave portions 10 in the first concave portion group G 1 in plan view is referred to as a “second straight line L 2 ”. The concave portion 10 of the panel member 1 must be arranged so that the angle θ between the first straight line L 1 and the second straight line L 2 is 80 degrees or more and 100 degrees or less. When the angle θ satisfies this range, the occurrence of large out-of-plane deformation can be suppressed. More preferably, the angle θ between the first straight line L 1 and the second straight line L 2 is 85 degrees or more. Also, the first straight line L It is more preferable that the angle θ formed by 1 and the second straight line L 2 is 95 degrees or less.
[0025]

　FIG. 4 is a cross-sectional view of the panel member 1 cut so as to include the centers of adjacent concaves 10 . In this specification, the distance between the recesses 10 is denoted by s, the diameter of the recesses 10 by d, and the depth of the recesses 10 by h. The distance s between the recesses 10 is the length of the surface of the panel member 1 on which the recesses 10 are not formed (R length from the stop to the R stop of the other ridge). Hereinafter, the surface on which the concave portion 10 is not formed will be referred to as a "reference surface". The distance s between the recesses can be changed as appropriate according to the required collision performance, the shape of the panel member 1, etc. The distance between adjacent recesses 10 within G 2 preferably satisfies s≦3d/10. When the distance s between the concave portions 10 is 3d/10 or less, the effect of suppressing the occurrence of large out-of-plane deformation can be enhanced.
[0026]
　Also, adjacent recesses 10 are preferably separated from each other on the reference plane in FIG. Here, "separated" means that there is no connecting portion such as a bridging portion. If the concave portions 10 are connected to each other by a connecting portion such as a bridging portion, the length of the side wall (side wall portion 10b) of the concave portion 10 is reduced by the amount of the connecting portion, thereby suppressing the occurrence of large out-of-plane deformation. less effective.
[0027]
　Further, in the panel member 1, it is preferable that the distance s between the recessed portions 10 in the first recessed portion group G1 and the recessed portions 10 in the second recessed portion group G2 also satisfies 3d/10 or less. The “distance between recesses s” when calculating the distance between the recesses 10 in the first recess group G 1 and the recesses 10 in the second recess group G 2 and the recess 10 in the second group of recesses G 2 that is closest to the recess 10 in question .
[0028]
　In this embodiment, the distances s between the recesses 10 in the first recess group G1 are equal, but the distances s between the recesses 10 may be different. Further, in the present embodiment, the distances s between the recesses 10 in the second recess group G2 are equal, but the distances s between the recesses 10 may be different. Further, in the present embodiment, the distances s between adjacent recesses 10 in the first recess group G1 and the second recess group G2 are the same, but the distances s between the recesses 10 are different. may In any case, if the relationship between the distance s between the recesses and the diameter d of the recesses 10 satisfies s≦3d/10, the effect of suppressing the occurrence of large out-of-plane deformation can be enhanced. The distance s between the recesses 10 is preferably, for example, 5 mm or more, and is preferably equal to or less than the diameter d of the recesses 10 .
[0029]
　In this embodiment, the diameters d of the recesses 10 provided in the panel member 1 are equal to each other, but the diameters d of the recesses 10 may be different from each other. In this case, the “diameter d of the recesses 10 ” used when calculating the relationship between the distance s between the adjacent recesses 10 and the diameter d of the recesses 10 is the average value of the diameters of the adjacent recesses 10 . The value of the diameter d of the concave portion 10 is appropriately changed according to the space around the panel member 1 and the moldability of the panel member 1, but is preferably 3 mm or more and 100 mm or less, for example. Also, the depth h of the concave portion 10 may be different from each other as well. The depth h of the recess 10 is preferably 3 mm or more, more preferably 5 mm or more. Moreover, the depth of the concave portion 10 is preferably 30 mm or less.
[0030]

　As shown in FIG. 4, the recess 10 according to the present embodiment is composed of a bottom 10a constituting the bottom surface of the recess and side walls 10b erected around the bottom 10a. be done. The angle between the bottom portion 10a and the side wall portion 10b (hereinafter, the inclination angle ξ of the side wall portion) is 20 degrees or more and 90 degrees or less, more preferably 45 degrees or more and 90 degrees or less, and still more preferably 60 degrees or more. . The closer the inclination angle ξ is to 90 degrees, the more the impact performance of the panel member 1 is improved. designed to
[0031]
　As mentioned above, although one Embodiment of this invention was described, this invention is not limited to this example. It is obvious that a person skilled in the art can conceive of various modifications or modifications within the scope of the technical idea described in the claims, and these are also within the technical scope of the present invention. be understood to belong to
[0032]
For example, in the above-described embodiment, the recesses 10 are arranged in two 　rows in parallel to form the first recess group G1 and the second recess group G2 along the X direction . The recesses 10 may be arranged in three parallel rows as in (1) to form a first recess group G1 and a second recess group G2 in the Y direction as well . As a result, the effect of suppressing the occurrence of out-of-plane deformation due to shear force can be enhanced. Further, in the above-described embodiment, a floor panel was described as an example of the panel member 1 of the automobile, but the panel member 1 is not limited to the floor panel, and for example, a roof panel, a hood inner panel, or a back door inner panel. may be It should be noted that the direction in which the first recessed portion group G1 and the second recessed portion group G2 are formed (for example, the vehicle length direction, the vehicle width direction, or the vehicle height direction) depends on the application location of the panel member 1. to be changed accordingly.
[0033]
　Further, in the above-described embodiment, the recessed portion 10 may be recessed when viewed from the inside of the vehicle of the panel member 1 or may be recessed when viewed from the outside of the vehicle. A configuration in which a concave shape and a convex shape are mixed when viewed from the inside may be used. In this case, the dimensions and configuration of the recessed shape viewed from the inside of the vehicle and the dimensions and configuration of the recessed shape viewed from the outside of the vehicle may both satisfy the conditions described in the above embodiment.
[0034]
　Further, in the above-described embodiment, the concave portion 10 is described as having a circular shape in plan view, but it does not necessarily have to be perfectly circular, and may be substantially circular or elliptical in plan view. When the concave portion 10 has an elliptical shape in a plan view, it is preferable to design the value of b/a, which is the ratio of the minor axis and the major axis, to be 1/3 or more and 2 or less, where a is the major axis of the ellipse and b is the minor axis of the ellipse. Furthermore, it is preferable to design it to be 1/2 or more and 2 or less. When the concave portion 10 has an elliptical shape, the diameter d of the concave portion described in the above embodiment may be the average diameter of the major axis a and the minor axis b.
Example
[0035]
An
　analytical model of a vehicle body having the floor panel shown in FIG. The analysis model floor panel has a recess with a depth of 5 mm and a recess diameter of 64 mm. Further, the distance between the recesses in the first group of recesses, the distance between the recesses in the second group of recesses, and the distance between the recesses in the first group of recesses and the recesses in the second group of recesses are each 14 mm. is. The angle .theta. (FIG. 2) formed by the first straight line and the second straight line indicating the positional relationship between the first group of recesses and the second group of recesses is 90 degrees. In addition, as a comparative example, an analysis model was created in which no concave portion was provided with respect to the analysis model of the example of the present invention, and a simulation was performed under the same conditions. Also, as a comparative example, an analysis model was created in the case where the angle θ was 60 degrees, and a simulation was performed under the same conditions. The vehicle width in the analysis model of the vehicle body was 170 mm, and the vehicle length was 250 mm.
[0036]
　FIG. 6 is a diagram showing the history of cross-sectional force (reaction force) of the floor including the frame generated when the impactor collides in the simulation of the comparative example. Moreover, FIG. 7 is a diagram showing the history of similar reaction force generated when the impactor collides in the simulation of the invention example. On the vertical axes of FIGS. 6 and 7, the magnitude of the reaction force in the negative region indicates the resistance force against collision. It should be noted that in the Time shown on the horizontal axis of each figure (FIGS. 6 to 8) according to this embodiment, the history of the load due to the collision reaching the floor panel after 60 ms is shown.
[0037]
　According to the results of FIGS. 6 and 7, the magnitude of the reaction force in the vehicle length direction and the vehicle width direction is greater in the invention example than in the comparative example. That is, by arranging the concave portions as in the example of the present invention, it is possible to increase the resistance to collision as a panel member and increase the amount of energy absorption. Also, FIG. 8 shows the simulation results when the angle θ is 60 degrees. As is clear from the comparison between FIG. 7 and FIG. The force can be increased and the crash performance can be improved.
[0038]
　Next, a plurality of analytical models with different angles θ were created, and simulations were performed under the same conditions as the above simulations. FIG. 9 shows the simulation results. As shown in FIG. 9, when the angle θ is in the range of 80 degrees or more and 100 degrees or less, the maximum reaction force against the axial force becomes larger than in the case of the conventional arrangement of the concave portions, and the collision performance is improved. is doing.
[0039]
　Next, a plurality of analysis models with different numbers of recesses in the vehicle length direction of the floor panel were created, and simulations were performed under the same conditions as the above simulations. The simulation result is shown in FIG. Note that the analytical model having three or more recesses shown in FIG. is doing. As shown in FIG. 10, when there are three recesses in the vehicle length direction, the reaction force in the vehicle width direction is approximately doubled compared to the case where there are two recesses, and a remarkable effect is obtained. appearing.
[0040]

　Fig. 11 is a diagram showing the relationship between the value of s/d and the maximum reaction force in the vehicle length direction, and is a graph of the analysis results using the same analysis model as in Embodiment 1 above. . In addition, Table 1 below shows the analysis results of this example.
[0041]
[table 1]

[0042]
　As shown in FIG. 11, when the value of s/d exceeds 0.3, the maximum reaction force in the vehicle length direction significantly decreases. This is because when the distance s between the recesses 10 is 3d/10 or less, the large out-of-plane deformation described above with reference to FIG. , that is, it indicates that the resistance to collision is increased. From this analysis result, it can be said that the relationship between the distance s between the recesses and the diameter d of the recesses preferably satisfies s≦3d/10, as described in the above embodiment.
[0043]

　FIG. 12 is a graph showing the relationship between the inclination angle ξ and the maximum reaction force in the longitudinal direction of the vehicle, and is a graph of the analysis results using the same analysis model as in Embodiment 1 above. In addition, Table 2 below shows the analysis results of this example.
[0044]
[Table 2]

[0045]
　As shown in FIG. 12, when the tilt angle ξ is 20 degrees or more, the maximum reaction force in the vehicle length direction increases slightly, and when the tilt angle ξ is 45 degrees or more, the maximum reaction force in the vehicle length direction increases. Furthermore, when the tilt angle ξ is 60 degrees or more, the maximum reaction force in the vehicle length direction increases more remarkably. From this analysis result, as described in the above embodiment, the inclination angle ξ, which is the angle formed by the bottom portion and the side wall portion of the recess according to the present invention, is preferably 20 degrees or more, and more preferably 45 degrees or more. It is preferable that the angle is 60 degrees or more.
[0046]

　Fig. 13 shows the relationship between the ratio b/a of the shortest and longest diameter and the maximum reaction force in the vehicle length direction in the same analysis model as in the first embodiment, when the shape of the concave portion is elliptical in plan view. It is a figure which shows. In addition, Table 3 below shows the analysis results of this example. In the floor panel of the analysis model in this embodiment, the major axis of the concave portion is set in the vehicle length direction, and the minor axis thereof is set in the vehicle width direction.
[0047]
[Table 3]

[0048]
　As shown in FIG. 13, when the concave shape is designed such that the minor/longer axis ratio b/a is 1/3 or more and 2 or less, the maximum reaction force in the vehicle length direction is larger than in the conventional case. It can be seen that the maximum reaction force in the vehicle length direction is greater when the ratio is between /2 and 2. From this analysis result, as described in the above embodiment, when the shape of the concave portion according to the present invention is an elliptical shape in a plan view, the minor/longer axis ratio b/a is designed to be 1/3 or more and 2 or less. It can be said that it is preferable to design to be 1/2 or more and 2 or less.
Industrial applicability
[0049]
　INDUSTRIAL APPLICABILITY The present invention can be used as a panel member such as a floor panel, a roof panel, a hood inner panel, or a back door inner panel.
Code explanation
[0050]
1 panel member
10 recess
d recess diameter
h recess depth
G recess group
G 1 　　first recess group
G 2 　　second recess group
L 1 　　first straight line
L 2 　　second straight line
s distance between recesses
θ first Angle between the straight line and the second straight line
ξ Angle between the bottom of the recess and the side wall (tilt angle)
The scope of the claims
[Claim 1]
Provided with a plurality of circular or elliptical recesses arranged in a straight line, and supposing that a portion in
　which three of the recesses are arranged in a straight line is called a recess group, at least a first recess group and the first recess group and a second group of recesses arranged in parallel to
　the center of the recess in the first group of recesses and the center of the recess in the second group of recesses closest to the recess. A first straight line connecting the center and a second straight line connecting the centers of the recesses in the first group of recesses forms an angle of 80 degrees or more and 100 degrees or less, and the
recesses are located on the bottom surface of the recesses. and sidewalls erected around the bottom,
wherein an inclination angle ξ between the bottom and the sidewalls is 20 degrees or more and 90 degrees or less.
[Claim 2]
Assuming that the diameter or average diameter of the recesses is d and the distance between the adjacent recesses is s, the distance between the adjacent recesses in the first recess group, the distance between the adjacent recesses in the second recess group wherein the distance between the recesses and the distance between the recesses in the first recess group and the recesses in the second recess group satisfy 5 ≤ s ≤ 3d/10 in units of mm. Item 1. The panel member according to item 1.
[Claim 3]
3. The panel member according to claim 1, wherein the inclination angle ξ is 45 degrees or more and 90 degrees or less.
[Claim 4]
4. The panel member according to any one of claims 1 to 3, wherein when the concave portion is elliptical, the ratio b/a of the major axis a to the minor axis b of the elliptical shape is 1/3 or more and 2 or less. .
[Claim 5]
5. The panel member is a floor panel of an automobile, and the recess is arranged along the vehicle length direction of the automobile in a group of three recesses arranged in a straight line. The panel member described in .