Inner panel for an automobile hood, automobile hood, and method for manufacturing an automobile hood

Abstract

[Problem] In an automobile hood, to enable pedestrian protection characteristics when a pedestrian collides with a rear portion of the automobile hood to be enhanced. [Solution] An inner panel 2 of an automobile hood 1 comprises: a pedestal 7 disposed toward an inner side of the inner panel 2 relative to an outer peripheral portion 5 of the inner panel 2; a plurality of units 9 each including a vertical wall 12 rising from the pedestal 7, and a flange 11 continuous with an upper edge of the vertical wall 12; and beads 21, 22 including at least one of a structure for connecting together outer edge portions 55 of the inner panel 2 in a height direction Z perpendicular to a plate thickness direction of the inner panel 2, and a structure for connecting an outer peripheral portion 73 of the pedestal 7 and the outer edge portion 55. A plurality of the beads 21, 22 are provided, and are disposed on a rear portion 1a side of the inner panel 2 in a vehicle length direction (length direction Y) of a vehicle in which the automobile hood 1 is installed.

Description

Technical Field

[0001] The present invention relates to an inner panel of an automobile hood, an automobile hood, and a method for manufacturing an automobile hood.

Background Art

[0002] An automobile, which is a type of vehicle, needs to ensure pedestrian protection performance assuming a collision with a pedestrian. When an automobile collides with a pedestrian, the hood located at the front of the automobile may collide with the pedestrian's head. It is desired that the automobile hood has a structure capable of reducing the injury to the pedestrian's head caused by this collision. An automobile hood has an inner panel and an outer panel. In order to reduce the injury during a pedestrian collision, proposals have been made regarding the inner panel (see, for example, Patent Documents 1 and 2).

[0003] The inner panel of the hood for a vehicle described in Patent Document 1 has as its problem to be solved the improvement of the protection performance of the pedestrian's head during a frontal collision between the automobile and the pedestrian. This inner panel is made of an aluminum alloy. This inner panel has a plurality of hat-shaped main beads arranged in the central portion excluding the edge portion. The main beads project upward or downward of the vehicle and are arranged parallel to each other.

[0004] The hood for a vehicle described in Patent Document 2 has as its problem to be solved the achievement of both an improvement in energy absorption performance when a collision body collides with the hood and an improvement in the deformation performance of the hood during a frontal collision (frontal impact). This hood for a vehicle has a bead (30) formed so as to extend along the front-rear direction of the hood in a skeleton forming portion arranged in the central region. At both end edges in the hood width direction, beads (22) arranged closer to the center in the vehicle front-rear direction are formed.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] The reason pedestrians sustain head injuries when they collide with a car is that the car's hood deforms during the collision, causing the pedestrian's head to strike components in the engine compartment through the hood. To reduce head injuries, it is necessary not only to increase the strength of the car's hood by using thicker or higher-strength materials, but also to create a structure that effectively absorbs and dissipates the impact of a collision.

[0007] There is a relatively large space between the components located in the engine compartment and the outer panel of the car hood in the central part of the hood. Therefore, it is easier to adopt structures in the central part of the car hood that reduce pedestrian injury in the event of a collision. On the other hand, the outer perimeter of the car hood has less space because it is connected to the surrounding panels and the car body by hinges, etc. Therefore, the pedestrian protection characteristics of the car hood tend to be good in the central part and poor in the outer perimeter. In particular, the pedestrian protection characteristics tend to be low when a pedestrian's head collides with the rear of the car hood.

[0008] However, the configurations described in Patent Documents 1 and 2 do not seem to take any particular consideration into account the pedestrian protection characteristics when a pedestrian's head collides with the rear of the car hood.

[0009] This invention has been made in view of the above-mentioned problems, and aims to improve the pedestrian protection characteristics of an automobile hood when a pedestrian collides with the rear of the automobile hood. [Means for solving the problem]

[0010] The present invention is essentially a car hood inner panel, a car hood, and a method for manufacturing a car hood.

[0011] (1) An inner panel for the car hood, A base is positioned on the inside of the inner panel relative to the outer periphery of the inner panel, Multiple units, each including a vertical wall rising from the base and a flange continuous with the upper end of the vertical wall, At least one of the beads, which connects the outer ends of the inner panels in a direction perpendicular to the thickness direction of the inner panel, and which connects the outer periphery of the base to the outer end, Equipped with, The inner panel of an automobile hood is provided with multiple beads and is located on the rear side of the inner panel in the vehicle length direction of the vehicle on which the automobile hood is installed.

[0012] (2) The inner panel of the automobile hood as described in (1), wherein each of the aforementioned beads has a height of 10 mm to 40 mm and a width of 10 mm to 40 mm.

[0013] (3) The inner panel of an automobile hood according to (1) or (2), wherein the flange of each unit is polygonal or circular when viewed in the thickness direction of the inner panel.

[0014] (4) An inner panel of an automobile hood as described in (3), wherein a plurality of the above units are arranged in the closest possible proximity.

[0015] (5) An inner panel for an automobile hood according to any one of (1) to (4) above, wherein, when the automobile hood is installed on the vehicle, the plurality of beads are arranged such that the suspension tower of the vehicle is positioned between the plurality of beads when viewed in the thickness direction of the inner panel.

[0016] The inner panel of the automobile hood according to any one of the above (1) to (5), which is composed of a steel plate with a thickness of 0.3 mm to 0.6 mm.

[0017] (7) An automobile hood comprising the inner panel according to any one of the above (1) to (6), and an outer panel disposed above the inner panel and joined to the flange.

[0018] (8) A method for manufacturing the automobile hood according to the above (7), wherein the automobile hood is manufactured as a test hood, and the impact value acting on the object is obtained when an impact load from an object is applied on the rear part of the test hood under the condition that a predetermined vehicle part is disposed below the test hood at a predetermined distance, and the bead is formed at a position set based on the relationship between the distance of the bead from the vehicle part in the thickness direction view of the inner panel and the impact value.

Effect of the Invention

[0019] According to the present invention, in an automobile hood, the pedestrian protection characteristics when a pedestrian collides with the rear part of the automobile hood can be improved.

Brief Description of the Drawings

[0020] [Figure 1] FIG. 1 is a schematic exploded perspective view of an automobile hood according to an embodiment of the present invention. [Figure 2] FIG. 2 is a plan view of the inner panel of the automobile hood. [Figure 3] FIG. 3 is a schematic cross-sectional view taken along line III-III of FIG. 2. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 2. [Figure 5] FIG. 5 is an enlarged view of a part of FIG. 3. [Figure 6]Figure 6(A) is an enlarged perspective view of the area around one unit of the inner panel. Figure 6(B) is a diagram illustrating the boundaries of each of the multiple units. [Figure 7] Figure 7 is a plan view showing the protruding structure extracted from the inner panel. [Figure 8] Figure 8 is a magnified view of the right rear portion of the inner panel. [Figure 9] Figure 9 is a right-side view of the inner panel, with a portion of the upper part of the overhang structure omitted from the illustration. [Figure 10] Figure 10 is a magnified view of the right rear area of ​​the inner panel shown in Figure 9. [Figure 11] Figure 11 is a perspective view of the rear right side of the inner panel. [Figure 12] Figure 12(A) schematically shows the cross-section perpendicular to the longitudinal direction of the first bead and the cross-section perpendicular to the longitudinal direction of the second bead, respectively, with the far side of the cross-section omitted. Figure 12(B) shows a modified example of the cross-sectional shape of the bead. [Figure 13] Figure 13 is a graph showing an example of the relationship between the distance from the center of the suspension tower to the first bead and the HIC (impact value). [Figure 14] Figure 14(A) is a schematic plan view of the main part of the inner panel showing a first modified example of the bead arrangement. Figure 14(B) is a schematic plan view of the main part of the inner panel showing a second modified example of the bead arrangement. Figure 14(C) is a schematic plan view of the main part of the inner panel showing a third modified example of the bead arrangement. Figure 14(D) is a schematic plan view of the main part of the inner panel showing a fourth modified example of the bead arrangement. [Figure 15] Figure 15(A) is a schematic plan view of the main part of the inner panel showing a fifth modified example of the bead arrangement. Figure 15(B) is a schematic plan view of the main part of the inner panel showing a sixth modified example of the bead arrangement. Figure 15(C) is a schematic plan view of the main part of the inner panel showing a seventh modified example of the bead arrangement. [Figure 16]Figure 16 shows a modified example of the unit, where Figure 16(A) is a schematic plan view of the main part, and Figure 16(B) is a cross-sectional view of one of the units in Figure 16(A). [Modes for carrying out the invention]

[0021] In the following, we will first explain the circumstances that led to the invention, and then describe the embodiments in detail.

[0022] [Background leading to the invention] One of the required characteristics of automobiles is pedestrian protection in the event of a collision. Furthermore, with the recent electrification of vehicles, there is a growing demand to suppress the increase in vehicle weight (reducing vehicle weight).

[0023] The inventors of this application investigated a vehicle hood structure that could achieve both weight reduction and panel rigidity while using a thin, high-strength steel material, in order to simultaneously satisfy the requirements of vehicle weight reduction and high pedestrian protection performance. In other words, they investigated a vehicle hood structure that could satisfy the conflicting requirements of vehicle weight reduction and high pedestrian protection performance.

[0024] The car hood is installed over the engine compartment. The car hood consists of an outer panel and an inner panel that is positioned inside the outer panel. The outer panel has a convex shape that faces outwards (upwards) and has a curved shape overall. In the center of the car hood, there is a relatively large space between the components installed in the engine compartment and the outer panel. On the other hand, the outer perimeter of the car hood has little space because it is connected to surrounding panels and the vehicle body by hinges, etc. Therefore, the pedestrian protection characteristics of the car hood tend to be good in the center and poor in the outer perimeter.

[0025] The inventors of this application conceived of providing a polygonal protrusion in the central part of the inner panel, where there is relatively ample space between it and the components in the engine compartment. This ensures panel rigidity of the automobile hood even with a thin wall. Furthermore, a through hole is formed at the top of the protrusion, and the inner panel is made lighter by making the protrusion a polygonal ring. In addition, the inventors conceived of strengthening the panel rigidity by installing a linear bead on the rear side (windshield side), which has a larger surface area, of the outer periphery of the inner panel, where the rigidity is lower than that of the central part of the inner panel. As a result, the inventors of this application have eliminated any areas of weak rigidity (areas with low pedestrian protection performance) in the entire inner panel of the automobile hood.

[0026] [Description of Embodiments] Embodiments of the present invention will be described below with reference to the drawings.

[0027] Figure 1 is a schematic exploded perspective view of an automobile hood 1 according to one embodiment of the present invention. Figure 2 is a plan view of the inner panel 2 of the automobile hood 1. Figure 3 is a schematic cross-sectional view along the line III-III in Figure 2. Figure 4 is a cross-sectional view along the line IV-IV in Figure 2. In Figures 3 and 4, the parts that appear behind the cross-section are omitted from the illustration. Also, in Figures 3 and 4, the outer panel 3, which is not shown in Figure 2, is indicated by a dashed line.

[0028] Figure 5 is an enlarged view of a portion of Figure 3. Figure 6(A) is an enlarged perspective view of the area around one unit 9 of the inner panel 2. Figure 6(B) is a diagram illustrating the unit boundaries 14 of the multiple units 9. Figure 7 is a plan view of the protruding structure 6 extracted from the inner panel 2. Figure 8 is an enlarged view of the right rear of the inner panel 2. Figure 9 is a right side view of the inner panel 2, with a portion of the upper part of the protruding structure 6 omitted from the illustration. Figure 10 is an enlarged view of the area around the right rear of the inner panel 2 in Figure 9. Figure 11 is a perspective view of the area around the right rear of the inner panel 2. In the following explanation, unless otherwise specified, Figures 1 to 11 will be referred to as appropriate.

[0029] Automobile hood 1 is a front hood installed on the front of an automobile, and is also called a bonnet. An automobile on which automobile hood 1 is installed is, for example, a passenger car. Examples of passenger cars include sedan-type passenger cars, coupe-type passenger cars, hatchback-type passenger cars, minivan-type passenger cars, and SUV (Sport Utility Vehicle)-type passenger cars.

[0030] In this specification, the front-rear, left-right, and up-down directions refer to the state when the car hood 1 is mounted on the vehicle and closed. Front is the direction in which the vehicle moves forward. Rear is the direction in which the vehicle moves backward. Right is the direction in which the vehicle turns when it is turning right while moving forward. Left is the direction in which the vehicle turns left while moving forward. In this embodiment, the width direction of the vehicle to which the car hood 1 is mounted is called the width direction X. The length direction of the vehicle to which the car hood 1 is mounted is called the length direction Y. The height direction of the vehicle to which the car hood 1 is mounted is called the height direction Z.

[0031] The automobile hood 1 includes an automobile inner panel 2, an automobile outer panel 3 supported by the automobile inner panel 2, and a joint 4 that connects the automobile outer panel 3 and the inner panel 2.

[0032] Hereafter, the automobile inner panel 2 will be referred to as inner panel 2, and the automobile outer panel 3 will be referred to as outer panel 3.

[0033] The outer panel 3 constitutes a part of the outer surface of the automobile in the automobile hood 1. The outer panel 3 is formed of a metallic material such as mild steel or high-tensile steel. Examples of high-tensile steel include steel plates with a tensile strength of 340 MPa or more, for example, steel plates with a tensile strength of 590 MPa or more. The outer panel 3 is formed, for example, by press-forming a single steel plate. The plate thickness t3 (plate thickness of the steel plate) of the outer panel 3 is preferably 0.6 mm or less, more preferably 0.5 mm or less, and even more preferably 0.4 mm or less. The lower limit of the plate thickness t3 of the outer panel 3 is, for example, 0.2 mm. The thinner the plate thickness t3 of the outer panel 3, the lighter the automobile hood 1 can be.

[0034] The outer panel 3 may be an aluminum alloy plate. If the outer panel 3 is an aluminum alloy plate, the thickness t3 of the outer panel 3 is preferably 0.4 mm to 1.2 mm, and more preferably 0.8 mm to 1.0 mm.

[0035] There are no particular restrictions on the shape of the outer panel 3. In this embodiment, the outer panel 3 has a shape that is convex upward in the height direction Z at its center.

[0036] The inner panel 2 is joined to the lower surface 3a of the outer panel 3, reinforcing the outer panel 3. This increases the tensile rigidity of the outer panel 3. Furthermore, in this embodiment, the inner panel 2 enhances the dent resistance of the outer panel 3. In other words, in this embodiment, the tensile rigidity and dent resistance of the outer panel 3 are ensured not by increasing the thickness of the outer panel 3, but by the shape of the inner panel 2.

[0037] Tension stiffness corresponds to the feeling of elastic resistance and deflection deformation when the outer panel 3 is pressed by hand. This characteristic is usually expressed as the amount of deflection when a load is applied. The smaller the amount of deflection when a certain load is applied, the higher the tension stiffness. Surface stiffness refers to the resistance of the outer panel 3 to deformation within a certain area when the outer panel 3 is subjected to a load such as a vertical load from the outer surface of the outer panel 3. Dent resistance is an index of how difficult it is for permanent deformation to remain after being pressed hard (an index that represents the resistance to dents and scratches). For example, if the outer panel has low dent resistance, it will easily get dented when pressed hard.

[0038] The inner panel 2 is made of a metal material such as a steel plate. The inner panel 2 is formed, for example, by press-forming a single steel plate. The inner panel 2 may be a single molded product or may be formed by joining multiple members together. In this embodiment, the inner panel 2 is a single molded product. The thickness t2 (thickness of the steel plate) of the inner panel 2 is preferably 0.3 mm to 0.6 mm, and more preferably 0.4 mm to 0.5 mm. The thickness t2 of the inner panel 2 may be less than the thickness t3 of the outer panel 3, the same as the thickness t3 of the outer panel 3, or greater than the thickness t3 of the outer panel 3.

[0039] The inner panel 2 may be an aluminum alloy plate. If the inner panel 2 is an aluminum alloy plate, the plate thickness t2 of the inner panel 2 is preferably 0.4 mm to 1.2 mm, and more preferably 0.6 mm to 1.0 mm.

[0040] The inner panel 2 has an outer periphery 5, an overhanging structure 6 arranged to surround the outer periphery 5, and a bead 20 formed on the outer periphery 5.

[0041] The outer periphery 5 is the outer periphery of the inner panel 2. When the outer panel 3 is closed, the outer periphery 5 of the inner panel 2 is supported by the vehicle body (not shown) together with the outer periphery of the outer panel 3. As a result, the load acting on the upper surface 3b of the outer panel 3 is supported by the vehicle body via the inner panel 2.

[0042] The outer periphery 5 includes an outer edge portion 51, a panel bottom portion 52 surrounded by the outer edge portion 51, and a rising portion 53 located at the rear of the panel bottom portion 52.

[0043] The outer peripheral edge 51 is the area where it is joined to the outer panel 3 by hemming. The panel bottom 52 and rising portion 53 are positioned so as to slope downward from the outer peripheral edge 51.

[0044] The panel bottom 52 is the bottom of the inner panel 2. The panel bottom 52 is formed in a three-dimensional shape with undulations. The undulations of the panel bottom 52 increase the bending rigidity of the outer periphery 5 of the inner panel 2. The panel bottom 52 includes a portion that undulates in the height direction Z. The specific shape of the panel bottom 52 is not specified.

[0045] As clearly shown in Figures 2, 8, and 11, a main rib 54 is formed on the bottom 52 of the panel, extending in the width direction X, behind the overhanging structure 6. The main rib 54 extends to connect the right and left sides of the outer peripheral edge 51. In this embodiment, the main rib 54 has a downwardly convex shape. In a view of the inner panel 2 in the thickness direction, the main rib 54 moves to the left from the right end 54a on the right side of the outer peripheral edge 51, facing the rear of the overhanging structure 6 in the width direction X, moves to the rear to bypass the outer peripheral 5 of the overhanging structure 6, then moves linearly to the left along the width direction X, moves forward to be adjacent to the outer peripheral 5 of the overhanging structure 6, and is then connected to the left side of the outer peripheral edge 51 at the left end 54b. In this specification, unless otherwise specified, the view in the thickness direction refers to the view of the inner panel 2 (outer panel 3) in the thickness direction.

[0046] The rising portion 53 is located on the rear side of the panel bottom portion 52 (behind the main rib 54). The first portion 53a of the rising portion 53, located behind the panel bottom portion 52, is an inclined wall that extends upward as it moves towards the rear. The second portions 53b, 53b of the rising portion 53, located to the right and left of the panel bottom portion 52, are inclined walls that extend upward as they move away from the center of the inner panel 2 in the width direction X.

[0047] The overhanging structure 6 has a three-dimensional structure provided to receive the load acting on the upper surface 3b of the outer panel 3. The overhanging structure 6 has a configuration that combines members with a hat-shaped cross-section (V-shaped or U-shaped cross-section). In this embodiment, the overhanging structure 6 has a shape that is symmetrical in the width direction X.

[0048] As clearly shown in Figures 2 and 7, the right end 61 of the overhanging structure 6 is positioned near the right portion of the outer peripheral edge 51 of the inner panel 2. The left end 62 of the overhanging structure 6 is positioned near the left portion of the outer peripheral edge 51 of the inner panel 2. The front end 63 of the overhanging structure 6 is positioned near the front portion of the outer peripheral edge 51 of the inner panel 2. The rear end 64 of the overhanging structure 6 is positioned near the rear portion of the outer peripheral edge 51 of the inner panel 2.

[0049] In this embodiment, the protruding structure 6 is a roughly elongated ellipse in the width direction X when viewed in the thickness direction. The right rear portion 65 of the protruding structure 6 is formed in a curved shape that is convex to the right rear when viewed in the thickness direction. Similarly, the left rear portion 66 of the protruding structure 6 is formed in a curved shape that is convex to the left rear when viewed in the thickness direction.

[0050] The cantilevered structure 6 includes a base 7, an incomplete unit 8 and a plurality of units 9 provided on the base 7.

[0051] The base 7 is positioned on the inside of the inner panel 2 relative to the outer periphery 5 of the inner panel 2.

[0052] The base 7 has a base vertical wall 71 that rises upward from the bottom 52 of the inner panel 2, and a top plate 72 that is continuous with the upper end of the base vertical wall 71. The outer periphery 73 of the base 7 is formed by the outer periphery of the top plate 72 and the base vertical wall 71.

[0053] The base vertical wall 71 is the outer edge of the protruding structure 6 when viewed in the plate thickness direction. The base vertical wall 71 is formed in an annular shape. The length of the base vertical wall 71 in the height direction Z is approximately a few millimeters to a few centimeters.

[0054] The top plate 72 is a plate-like portion formed to conform to the shape of the outer panel 3. Specifically, the distance between the top plate 72 and the outer panel 3 at each part of the top plate 72 is kept approximately constant. The top plate 72 supports the incomplete unit 8 and the unit 9.

[0055] Each unit 9 is formed in a polygonal (hexagonal in this embodiment) annular shape when viewed in the thickness direction. By forming each unit 9 in a small annular polygonal shape, the inner panel 2 can be made lightweight while also having high rigidity.

[0056] In this embodiment, each unit 9 is formed in a substantially regular hexagonal shape. The corners of the regular hexagon are rounded. A regular hexagon is a hexagon in which all sides are of equal length and the interior angles are constant at 120 degrees. In this specification, "substantially regular hexagon" means a hexagon that can be treated as a regular hexagon in terms of the tensile rigidity and dent resistance of the outer panel 3. The shape of each unit 9 is formed to be substantially the same. In this case, "substantially the same" means that the configuration is the same except that the shape of each unit 9 is matched to the curved shape of the outer panel 3.

[0057] Each unit 9 may be formed as a hexagon other than a regular hexagon. Examples of hexagons other than regular hexagons include hexagons with uneven side lengths and hexagons with interior angles that are not uniformly 120 degrees. An example of a hexagon with uneven side lengths is a hexagon in which the front and rear sides have a predetermined first length, and the other four sides have a predetermined second length different from the first length.

[0058] The cantilever structure 6 has a structure in which multiple hexagonal ring-shaped units 9 are arranged in the tightest possible density. In this case, "tightest density" means that multiple adjacent units 9 are arranged without any gaps. Specifically, each unit 9 is separated from other units 9 by a unit boundary 14, which will be described later. As shown in Figure 6(B), the tip 12a (lower end) of the vertical wall 12 forms the boundary of the unit 9 that includes the tip 12a, thereby forming the unit boundary 14. This unit boundary 14 is formed in a hexagonal shape in plan view. By adopting such polygonal units 9, the surface rigidity of the areas of the automobile hood 1 where the units 9 are arranged can be made higher, as will be described later. Furthermore, because multiple units 9 are arranged in the tightest density as described above, the cantilever structure 6 can resist loads in all directions, including the height direction Z, in a substantially similar manner across the entire area in the plate thickness direction view. As a result, even if the inner panel 2 and outer panel 3 are made thinner and lighter, the surface rigidity of the automobile hood 1 can be made higher.

[0059] Referring to Figures 2, 5, 6(A), and 6(B), when the units 9 are arranged in the closest possible location, it is preferable that multiple units 9 have the same shape. Units 9 of different shapes or similar shapes may be arranged in the closest possible location. In the overhanging structure 6, the units 9 do not have to be arranged in the closest possible location, and other parts may be formed between adjacent units 9, 9.

[0060] In this embodiment, the multiple units 9 are formed symmetrically with respect to the width direction X. For example, in this embodiment, three units 9 are arranged in the front-to-back direction at the center of the width direction X. In a plan view, the multiple units 9 are arranged symmetrically with respect to the width direction X, with respect to a virtual line A1 that passes through the center of the three units 9 in the width direction X and extends front-to-back. It should be noted that the tension rigidity and dent resistance of the outer panel 3 are not limited to this configuration, and do not depend on the orientation of the units 9 with respect to the width direction X or the length direction Y in a plan view. Therefore, there are no restrictions on the orientation of the units 9.

[0061] In this embodiment, starting from the three units 9 positioned in the center of the width direction X, four units 9 are arranged in the length direction Y in order to the right, followed by three more units 9 arranged in the length direction Y, followed by two more units 9 arranged in the length direction Y, and then two more units 9 arranged in the length direction Y. Similarly, starting from the three units 9 positioned in the center of the width direction X, four units 9 are arranged in the length direction Y in order to the left, followed by three more units 9 arranged in the length direction Y, followed by two more units 9 arranged in the length direction Y, and then two more units 9 arranged in the length direction Y.

[0062] Each unit 9 has six subunits 10 (10a to 10f). In this embodiment, in each unit 9, the front subunit 10a and the rear subunit 10d extend along the width direction X, respectively. In each unit 9, the remaining four subunits 10 extend in a direction inclined with respect to the length direction Y in a plan view. In this way, a polygonal unit 9 is formed by multiple subunits 10.

[0063] Each subunit 10 (10a to 10f) has a vertical wall 12 rising from the top plate 72 of the base 7, and a flange 11 that is continuous with the upper end of the vertical wall 12.

[0064] The flange 11 is adjacent to the outer panel 3 and is the part of the partial unit 10 that is closest to the outer panel 3. The flange 11 is a strip-shaped portion. In one unit 9, the flanges 11 of the six partial units 10a to 10f together form an annular flange 13 with a hexagonal outer shape when viewed in the thickness direction. The outer shape of the annular flange 13 may be a polygon other than a hexagon, or it may be approximately circular or approximately elliptical. Each corner of the outer shape of the annular flange 13 is rounded to alleviate stress concentration. In this embodiment, the inner edge of the annular flange 13 is formed in a hexagon. The inner edge of the annular flange 13 may be a polygon other than a hexagon, or it may be circular or elliptical. The width of the flange 11 where the joint portion 4 is provided is preferably 2 mm or more. This allows for a sufficient amount of joint portion 4 to be provided.

[0065] In this embodiment, in each unit 9, the flange 11 of at least some of the partial units 10 is provided with a joint 4. The inner panel 2 is joined to the outer panel 3 via this joint 4. That is, the outer panel 3 is positioned above the inner panel 2 and joined to the annular flange 13. A vertical wall 12 extends downward from the flange 11.

[0066] The vertical wall 12 connects the flange 11 and the top plate 72. The vertical wall 12 is provided over the entire length L of the subunit 10 on which the vertical wall 12 is located. The vertical wall 12 is formed in a sloping shape, for example, that it moves toward the central axis of the unit 9 as it approaches the outer panel 3.

[0067] A flange 11 is continuous with the upper end of the vertical wall 12. A top plate 72 is continuous with the lower end of the vertical wall 12. The flange 11 and the vertical wall 12 are continuous with each other in a smoothly curved shape, making stress concentration unlikely. Similarly, the vertical wall 12 and the top plate 72 are continuous with each other in a smoothly curved shape, making stress concentration unlikely.

[0068] The lower end 12a of the vertical wall 12 is the part of the unit 9 that is furthest from the outer panel 3. The tip of the lower end 12a of the vertical wall 12 is integral with the tip of the lower end 12 of the vertical wall 12 in the adjacent unit 9, and is integral with the top plate 72. In one unit 9, the tips of the lower ends 12a of the six vertical walls 12 in the six subunits 10a to 10f form a hexagonal unit boundary 14 as a whole.

[0069] In this embodiment, the height of unit 9 in the height direction Z is the distance between the top plate 72 and the upper surface of the flange 11 in the height direction Z. The height of unit 9 is preferably 10 mm or more. When this height is 10 mm or more, the second moment of area with respect to the bending force that attempts to bend the inner panel 2, that is, the bending force that causes part or all of the inner panel 2 to bend into an arc, can be made higher. This makes it possible to suppress the bending deformation of the inner panel 2 and the outer panel 3 joined to the inner panel 2. This height is preferably 13 mm or more.

[0070] In this embodiment, the joint 4 is an adhesive. A mastic sealer (mastic adhesive) can be exemplified as this adhesive. A resin-based adhesive can be exemplified as this mastic sealer. The adhesive may have properties that cure at room temperature (for example, 20 degrees Celsius), or it may have properties that cure through a heating process or a drying process.

[0071] The joint portion 4 is provided on at least one of the multiple flanges 11 of the inner panel 2 in each unit 9. The joint portion 4 connects the flange 11 on which the joint portion 4 is provided to the lower surface 3a of the outer panel 3.

[0072] The incomplete unit 8 has a configuration that corresponds to a configuration in which a portion of the polygonal (hexagonal in this embodiment) unit 9 is missing along the circumferential direction. The incomplete unit 8 has edges similar to those of the partial unit 10 of unit 9.

[0073] In this embodiment, the incomplete units 8 are provided at five locations (incomplete units 8a to 8e) on the front of the overhanging structure 6, and at five locations (incomplete units 8f to 8j) on the rear of the overhanging structure 6.

[0074] Incomplete unit 8a is positioned in front of the rightmost unit 9 and forms a ring containing two subunits 10. Incomplete unit 8b is positioned in front of the third unit 9 from the right and forms a ring containing two subunits 10. Incomplete unit 8c is positioned in front of the central unit 9 in the width direction X and forms a ring containing four subunits 10. Incomplete unit 8d is positioned in front of the third unit 9 from the left and forms a ring containing two subunits 10. Incomplete unit 8e is positioned in front of the leftmost unit 9 and forms a ring containing two subunits 10.

[0075] The incomplete unit 8f is located behind the second unit 9 from the right. The incomplete unit 8f is formed in an ended shape that includes a part of a hexagon and contains five subunits 10. The incomplete unit 8g is located behind the third unit 9 from the right. The incomplete unit 8g is formed in an ended shape that includes a part of a hexagon and contains three subunits 10. The incomplete unit 8h is located behind the central unit 9 in the width direction X. The incomplete unit 8h is formed in a trapezoidal ring shape that includes four subunits 10. The incomplete unit 8i is located behind the third unit 9 from the left. The incomplete unit 8i is formed in an ended shape that includes a part of a hexagon and contains three subunits 10. The incomplete unit 8j is located behind the second unit 9 from the left. The incomplete unit 8j is formed in an ended shape that includes a part of a hexagon and contains five subunits 10.

[0076] A bead 20 is positioned on the rear side of the overhanging structure 6 having the above configuration.

[0077] The bead 20 is provided to ensure rigidity against impact loads acting from above on the rear 1a of the car hood 1 (rigidity of the surface of the car hood 1; hereinafter also referred to as the surface rigidity of the rear 1a of the hood). For example, when a vehicle equipped with the car hood 1 collides head-on with a pedestrian, if the surface rigidity of the rear 1a of the hood is high, the amount of impact absorbed by the car hood 1 from the pedestrian, especially the pedestrian's head, can be increased. Therefore, the impact that the pedestrian receives from parts in the engine compartment can be reduced, thereby improving pedestrian protection performance. In other words, the bead 20 is provided to lower the head injury criterion (HIC).

[0078] As clearly shown in Figures 2 and 8 to 11, multiple beads 20 are provided on the inner panel 2. The beads 20 are located on the rear 1a side of the car hood 1 in the vehicle length direction (length direction Y). The rear 1a refers, for example, to the portion of the car hood 1 rearward from the center in the length direction Y. The rear 1a may also refer to the rear 1 / 3 portion of the car hood 1 in the length direction Y. The beads 20 are located on the rear 1a side of the inner panel 2 where there is no protruding structure 6 and the area is large. In this embodiment, multiple beads 20 are provided, including a first bead 21 and a second bead 22.

[0079] The first bead 21 and the second bead 22 are positioned as a set, with beads 21 and 22 located on the right and left sides of the inner panel 2, respectively. By positioning at least two beads 21 and 22 as a set in this way, more uniform surface rigidity can be ensured at the rear portion 1a of the automobile hood 1. The beads 21 and 22 on the right side of the inner panel 2 and the beads 21 and 22 on the left side of the inner panel 2 are positioned symmetrically in the width direction X. Each bead 21 and 22 is located on the rear side of the overhanging structure 6. In this embodiment, each bead 21 and 22 is positioned near the outer peripheral edge 51 of the inner panel 2 in the width direction X, and is spaced away from the central position of the inner panel 2 in the width direction X. In this embodiment, the two beads 21 and 22 on the right side will be mainly described. The two beads 21 and 22 on the left side will be described in lieu of the description of the two beads 21 and 22 on the right side.

[0080] The second bead 22 is positioned near the outer edge of the inner panel 2 in the width direction X. The first bead 21 is positioned inward in the width direction X relative to the second bead 22. Each bead 21, 22 has a configuration that connects the outer periphery 73 of the base 7 and the outer end 55 of the inner panel 2 in a direction perpendicular to the thickness direction (height direction Z) of the inner panel 2 (horizontal direction). In this case, "outer end 55 of the inner panel 2" refers to the point where the bead 20 and the outer periphery 5 of the inner panel 2 (for example, the rising portion 53) are connected when the bead 20 is advanced in the longitudinal direction of the bead 20 at the location where the bead 20 is positioned. In this embodiment, "outer end 55 of the inner panel 2" does not refer to the outer periphery edge 51 (edge) of the inner panel 2 when viewed in the thickness direction. However, the outer end 55 may refer to the outer periphery edge 51.

[0081] In this embodiment, each bead 20 (21, 22) is arranged linearly when viewed in the thickness direction of the plate. This increases the rigidity of the inner panel 2 as a surface.

[0082] Figure 12(A) schematically shows the cross-section perpendicular to the longitudinal direction of the first bead 21 and the cross-section perpendicular to the longitudinal direction of the second bead 22. In Figure 12(A), the far side of the cross-section is omitted. Hereafter, the cross-section perpendicular to the longitudinal direction of each bead 21, 22 will simply be referred to as "cross-section".

[0083] Referring to Figure 12(A), in this embodiment, each bead 21, 22 is formed by press-molding the material with the material facing upward. In this way, it is preferable that each bead 21, 22 is convex toward the outer panel 3. In this case, the beads 21, 22 are located on the inside of the bend of the inner panel 2 caused by the compressive load generated in the inner panel 2 due to a pedestrian's collision with the car hood 1. Therefore, the degree to which the beads 21, 22 contribute to the surface rigidity of the inner panel 2 can be increased. Each bead 21, 22 may also be formed by press-molding the material of the inner panel 2 with the material facing downward.

[0084] In this embodiment, the cross-sectional shape of each bead 21, 22 is an arc shape. It is preferable that the cross-sectional shape of each bead 21, 22 is composed of a smooth curve in order to suppress stress concentration. The cross-sectional shape of each bead 21, 22 may be an elliptical arc shape that protrudes more upward from the arc shape shown in Figure 12(A), or a polygonal shape (a hat shape in Figure 12(B)) as shown in Figure 12(B). Figure 12(B) shows a modified example of the cross-sectional shape of bead 20 (21, 22).

[0085] When the cross-sectional shape of each bead 21, 22 is an arc shape, it is preferable that the radius of curvature R of the arc be 10 mm to 40 mm. The height H (maximum height) of each bead 21, 22 is preferably 10 mm to 40 mm. Also, the width W (maximum width) of each bead 21, 22 is preferably 10 mm to 40 mm. If at least one of the radius of curvature R, height H, and width W of each bead 21, 22 satisfies the above range, stress concentration in the inner panel 2 caused by each bead 21, 22 can be suppressed. In this case, the effect of improving the surface rigidity of the inner panel 2 due to each bead 21, 22 can be more greatly exhibited. The upper limits of the radius of curvature R, height H, and width W of each bead 21, 22 may exceed 40 mm and are set according to the size of the automobile hood 1.

[0086] Referring to Figures 8 to 11, the upper ends 21a and 22a of each bead 21 and 22 extend in a straight line approximately parallel to the top plate 72. The lower ends 21b and 22b of each bead 21 and 22 are continuous with the panel bottom 52, the rising portion 53, and the base vertical wall 71 of the outer periphery 5 of the inner panel 2. The height position of the lower ends 21b and 22b of each bead 21 and 22 changes as they progress along the longitudinal direction of each bead 21 and 22.

[0087] In this embodiment, the first bead 21 extends diagonally outward and rearward from the overhanging structure 6. The longitudinal component of the first bead 21 is larger in the length direction Y than in the width direction X, and it can be said that the first bead 21 is generally oriented in the length direction Y. One end 21c (front end) of the first bead 21 is connected to the outer periphery 73 of the base 7. In this embodiment, one end 21c is connected to the right rear portion 65 of the overhanging structure 6, which is curved when viewed in the thickness direction. One end 21c of the first bead 21 is open to the space inside the vertical wall 71 of the base. The other end 21d (rear end) of the first bead 21 is connected to the outer end portion 55 of the inner panel 2. In this embodiment, the other end 21d is located on the rising portion 53 of the outer periphery 5. The other end 21d of the first bead 21 is open to the rear surface 53c side of the rising portion 53.

[0088] In this embodiment, the second bead 22 extends diagonally outward and rearward from the overhanging structure 6. The longitudinal direction of the second bead 22 has a larger widthwise X component than a lengthwise Y component, and it can be said that the second bead 22 is generally oriented in the widthwise X direction. One end 22c (front end) of the second bead 22 is connected to the outer periphery 73 of the base 7. In this embodiment, one end 22c is connected to the right rear portion 65 of the overhanging structure 6, which is curved when viewed in the thickness direction. This end 22c is adjacent to the first bead 21 at a distance of less than the width of one unit 9. The distance between the ends 21c and 22c of each bead 21 and 22 can be appropriately set in accordance with the target rigidity value of the inner panel 2 provided by the beads 21 and 22. One end 22c of the second bead 22 is open to the space inside the vertical wall 71 of the base. The other end 22d (rear end) of the second bead 22 is located on the right rear of the panel bottom 52, approximately several tens of mm inward in the width direction X from the outer peripheral edge 51. The other end 22d of the second bead 22 is connected to the outer end 55 (second portion 53b of the rising portion 53) of the inner panel 2 and is open to the outside of the inner panel 2 in the width direction X.

[0089] In this embodiment, the intermediate portions of each bead 21, 22 are positioned to straddle the main rib 54 (see Figure 11). With this configuration, the rigidity of the inner panel 2 can be increased through the cooperation of each bead 21, 22 and the main rib 54. At least one of the beads 21, 22 does not have to be positioned to intersect the main rib 54.

[0090] It is preferable that the distance between the upper ends 21a, 22c of the beads 21, 22 and the outer panel 3 in the height direction Z is greater than the height H of the beads 21, 22. With this configuration, a greater distance can be secured between the inner panel 2 and the outer panel 3 at the outer peripheral portion 5 of the inner panel 2. By securing a greater distance between the inner panel 2 and the outer panel 3, the torsional rigidity of the automobile hood 1 can be increased. It is preferable that the distance between the panel bottom portion 52 and the inner panel 2 at the outer peripheral portion 5 of the inner panel 2 be 40 mm or more, and more preferably 50 mm or more. Furthermore, by arranging the beads 21, 22 in a location where a greater distance is secured between the inner panel 2 and the outer panel 3, the surface rigidity of the inner panel 2 is also secured.

[0091] In this embodiment, when the automobile hood 1 is installed on the vehicle, the multiple beads 21, 22 are arranged such that the vehicle's suspension tower 101 is positioned between the multiple beads 21, 22 when viewed in the thickness direction of the inner panel 2.

[0092] As clearly shown in Figures 2 and 8, the suspension tower 101 is part of the vehicle body 100. The suspension tower 101 is made of steel plate or aluminum alloy plate, etc. The suspension tower 101 is formed, for example, as a hollow column. The upper end portion 102 of the suspension tower 101 is formed in the shape of a rectangle or a circle, etc., and the upper end portion of a shock absorber (not shown) is attached to it. This upper end portion 102 is provided with a through hole 102a formed substantially coaxially with the upper end portion of the shock absorber. In this embodiment, the center of the through hole 102a is the suspension tower center S101. The suspension tower center S101 may be other than the center of the through hole 102a. The shock absorber is connected to the suspension tower 101 and to a hub (not shown) connected to the tire of the front wheel, etc.

[0093] The beads 21 and 22 are positioned so as to sandwich the suspension tower 101 when viewed in the thickness direction. In this embodiment, the suspension tower 101 is positioned below the bottom 52 of the panel. In this embodiment, the beads 21 and 22 are positioned so as not to overlap with the upper end 102 of the suspension tower 101 when viewed in the thickness direction. At least one of the beads 21 and 22 may be positioned to overlap with the upper end 102 of the suspension tower 101 when viewed in the thickness direction.

[0094] Referring to Figures 1, 2, and 8, we consider a suitable location for placing the first bead 21. Specifically, we consider a conventional example where a flat inner panel shape is used instead of beads 21 and 22 at the location where beads 21 and 22 are placed. In this case, when the aforementioned impact load acts on the suspension tower 101 at the rear 1a of the car hood 1, the inner panel 2 bends downward, for example, at a bending position P1 behind the outermost unit 9 in the width direction X of the overhang structure 6 and near the outer peripheral edge 51 of the inner panel 2. When such bending occurs, the surface rigidity of the car hood 1 decreases, and the amount of impact load absorbed decreases. As a result, the inner panel 2 comes into contact with the suspension tower 101 due to the impact load. This contact makes it easier for the reaction force from the suspension tower 101 to be transmitted to pedestrians via the inner panel 2. Therefore, HIC worsens. Having obtained these findings, the inventors of the present invention conceived of devising a preferred arrangement range for the first bead 21 with respect to the suspension tower center S101.

[0095] Specifically, first, a vehicle hood 1 is fabricated as a test hood. Next, a suspension tower 101 (a predetermined vehicle component) is placed at a predetermined distance (for example, 50 mm) below the test hood (vehicle hood 1). Under these conditions, an impact load from a head impactor 200 is applied to the rear part 1a of the outer panel of the test hood (vehicle hood 1). The head impactor 200 is an object that mimics the head of a human body. The head impactor 200 is, for example, a sphere with a diameter of approximately 165 mm. The point of application P2 of the impact load is, for example, directly above the suspension tower 101 on the test hood (vehicle hood 1). As a more specific example, the point of application P2 is, for example, with a C-segment vehicle in mind, at a position where the WAD (Wrap Around Distance) from the ground at the front end of the vehicle along the vehicle surface is 1600 mm, and the distance from the center in the width direction of the test hood (vehicle hood 1) is 600 mm. The collision conditions for the head impactor 200 are, for example, from the front at an angle (65 degrees from the horizontal) relative to the test hood (automobile hood 1) at a speed of 40 km / h. The impact value (HIC) acting on the head impactor 200 under these collision conditions is to be determined. The method for calculating HIC is publicly known, so the explanation is omitted. The automobile hood 1 is assumed to be supported by the outer periphery 5 of the inner panel 2 on the vehicle body. Other conditions are based on the state in which the automobile hood 1 is actually installed on the vehicle.

[0096] The test hood of the automobile hood 1, the suspension tower 101, and the head impactor 200, etc., may be actually manufactured or created as computer models.

[0097] The HIC calculation described above is performed multiple times, while fixing the positions of the point of application P2 and the second bead 22, and changing the distance D from the suspension tower center S101 to the first bead 21 in the width direction X. This allows us to determine the relationship between the distance D from the suspension tower center S101 to the first bead 21 and the HIC (impact value), as shown in Figure 13. Figure 13 is a graph showing an example of the relationship between the distance D from the suspension tower center S101 to the first bead 21 and the HIC (impact value). Distance D refers to the shortest distance between the suspension tower center S101 and the first bead 21 when viewed in the plate thickness direction. This graph shows an example where the HIC was calculated four times by changing the distance D, and a trend line L was calculated from the results. In this graph, the HIC rises sharply from around 150 mm in distance D. Keeping the distance D below the value of distance D near the change point La where such a sharp change occurs is effective in reducing the HIC. In this embodiment, the first bead 21 is formed at a position set based on this trend line L.

[0098] In this embodiment, the distance D from the center S101 of the suspension tower to the first bead 21 is preferably within 200 mm, and more preferably within 150 mm. It is even more preferable that the distance D is smaller than the distance D (130 mm) at the position where a fold occurs in the inner panel 2 when the above HIC calculation is performed, when beads 21 and 22 are omitted.

[0099] As described above, according to this embodiment, the inner panel 2 and the outer panel 3 are joined at multiple flanges 11 (annular flanges 13) of the overhanging structure 6, while the beads 21 and 22 connect the outer peripheral portion 73 of the base 7 to the outer end portion 55 of the inner panel 2. With this configuration, the bending rigidity of the inner panel 2 at the rear portion 1a of the car hood 1 is increased by the beads 21 and 22. As a result, when a pedestrian's head, for example, collides with the rear portion 1a of the car hood 1, the car hood 1 can support the pedestrian with high rigidity. Therefore, it is possible to suppress a pedestrian from colliding with the lower member of the car hood 1, or to mitigate the impact caused by contact with the lower member. For the reasons described above, the pedestrian protection characteristics when a pedestrian collides with the rear portion 1a of the car hood 1 can be further improved.

[0100] In this embodiment, the suspension tower 101 is positioned between multiple beads 21 and 22 when viewed in the thickness direction. This configuration allows for increased bending rigidity in the area above where the suspension tower 101 is located on the car hood 1. As a result, when a pedestrian collides with the rear 1a of the car hood 1, the car hood 1 can receive the pedestrian with high rigidity, mitigating the impact on the pedestrian and reducing the impact the pedestrian receives from the suspension tower 101.

[0101] In this embodiment, the inner panel 2 is made of a steel plate with a thickness t2 of 0.3 mm to 0.6 mm. When the thickness of the inner panel 2 is 0.6 mm or less, the inner panel 2 can be made lighter. On the other hand, in this case, the bending rigidity of the inner panel 2 tends to decrease. However, by providing beads 21 and 22, the surface rigidity of the automobile hood 1 at the rear portion 1a of the automobile hood 1 can be increased to a practically acceptable level.

[0102] As described above, according to this embodiment, the car hood 1 is made lightweight by forming the inner panel 2 and outer panel 3 from thin sheet material. Furthermore, sufficient surface rigidity is ensured by providing an overhanging structure 6 containing multiple hexagonal units 9 in the center of the car hood 1. In addition, in the wide and thin rear portion 1a of the car hood 1 behind the overhanging structure 6, beads 21 and 22 are provided as a set in pairs on the left and right. This ensures sufficient surface rigidity even in the area of ​​the car hood 1 behind the overhanging structure 6, where it is difficult to ensure surface rigidity due to its thinness and width. In this way, a lightweight car hood 1 with high overall surface rigidity (pedestrian protection characteristics), including the rear portion 1a, can be realized.

[0103] Embodiments of the present invention have been described above. However, the present invention is not limited to the embodiments and modifications described above. Various modifications are possible within the scope of the claims. In the following, configurations different from the embodiments described above will be mainly described, and similar configurations will be denoted by the same reference numerals in the figures and detailed descriptions will be omitted.

[0104] <Variations in bead placement> In the embodiments described above, a configuration in which beads 21 and 22 are arranged on the right and left sides of the automobile hood 1 was used as an example. However, this configuration is not required. The number of beads 20 and the longitudinal direction of the beads in view in the thickness direction are not limited to the configuration described above. In the modified configuration of beads 20 described below, a part of the inner panel 2 is shown. The explanation assumes that multiple beads are arranged symmetrically in the width direction X.

[0105] <First variation of bead arrangement (vertical stripe arrangement)> Figure 14(A) is a schematic plan view of the main part of the inner panel 2. Figure 14(A) shows a first modified example of the bead arrangement. In the first modified example, a plurality of beads 20A are provided parallel to the length direction Y and spaced apart from each other in the width direction X. Each bead 20A is a bead that connects the outer periphery 73 of the base 7 and the outer end 55 of the inner panel 2. The bead 20A is the same as the configuration of the first bead 21 described above, except that it is parallel to the length direction Y. It is preferable that the plurality of beads 20A are arranged at equal pitches in the width direction X. The plurality of beads 20A may be arranged at unequal pitches in the width direction X. The plurality of beads 20A are arranged over substantially the entire width direction X at the rear part 1a of the automobile hood 1. The front end of the outermost bead 20A' in the width direction X is not connected to the outer periphery 73 of the base 7, but is located in the middle of the panel bottom 52. However, this type of bead 20A' also contributes to improving the bending rigidity of the inner panel 2.

[0106] <Second variation of bead arrangement (horizontal stripe arrangement)> Figure 14(B) shows a second modified example of the bead arrangement. In the second modified example, multiple beads 20B are provided parallel to the width direction X and spaced apart from each other in the length direction Y. The two front beads 20B connect the outer circumference 73 of the base 7 and the outer end 55 of the inner panel 2. The rearmost bead 20B connects the outer end 55 of the inner panel 2 to each other. The bead 20B is the same as the configuration of the first bead 21 described above, except that it is parallel to the width direction X. It is preferable that the beads 20B are arranged at equal pitches in the length direction Y. Multiple beads 20B may be arranged at unequal pitches in the length direction Y.

[0107] <Third variation of bead arrangement (lattice arrangement)> Figure 14(C) shows a third modified example of the bead arrangement. In this third modified example, beads 20A parallel to the length direction Y and beads 20B parallel to the width direction X are arranged in a grid pattern. The configuration of beads 20A is the same as that of bead 20A shown in Figure 14(A). The configuration of beads 20B is the same as that of bead 20B shown in Figure 14(B).

[0108] <Fourth variation of bead arrangement (radial arrangement)> Figure 14(D) shows a fourth modified example of the bead arrangement. In the fourth modified example, multiple beads 20D are arranged radially from the overhang structure 6 in the thickness direction. The multiple beads 20D are provided at intervals in the circumferential direction of the overhang structure 6. Each bead 20D is a bead that connects the outer circumference 73 of the base 7 and the outer end 55 of the inner panel 2. The bead 20D is the same as the configuration of the first bead 21 described above, except for the longitudinal direction in the thickness direction. It is preferable that the beads 20D are arranged at equal pitches in the circumferential direction of the overhang structure 6. The beads 20D may be arranged at unequal pitches in the circumferential direction of the overhang structure 6. It is preferable that the multiple beads 20D are arranged on the outside in the width direction X at the rear part 1a of the automobile hood 1. In the thickness direction, the beads 20D are arranged radially with a center, for example, outside the center in the width direction X of the overhang structure 6. By arranging the beads 20D radially in this way, the beads 20D are distributed over a wider area at the rear of the car hood 1, thereby increasing the effect of improving the surface rigidity of the car hood 1.

[0109] <Fifth variation of bead arrangement (front outer stripe arrangement)> Figure 15(A) shows a fifth modified example of the bead arrangement. In the fifth modified example, multiple beads 20E extend diagonally outward in the direction of the plate thickness. The multiple beads 20E are spaced apart in a direction perpendicular to the longitudinal direction of the beads 20E. Some of the beads 20E are used to connect the outer circumference 73 of the base 7 and the outer end 55 of the inner panel 2. The remaining beads 20E connect the outer end 55 of the inner panel 2 to each other. The configuration of the beads 20E is the same as that of the first bead 21 described above, except that they extend diagonally outward in the direction of the front. Preferably, the beads 20E are arranged at equal pitches in a direction perpendicular to the longitudinal direction of the beads 20E in the direction of the plate thickness. The beads 20E may be arranged at unequal pitches in a direction perpendicular to the longitudinal direction of the beads 20E. Preferably, the multiple beads 20E are arranged over substantially the entire width X area at the rear 1a of the automobile hood 1. Multiple beads 20E may be arranged only on the outer end side in the width direction X at the rear portion 1a.

[0110] <Sixth variation of bead arrangement (front inner stripe arrangement)> Figure 15(B) shows a sixth modified example of the bead arrangement. In the sixth modified example, multiple beads 20F extend diagonally inward and forward when viewed in the thickness direction. The multiple beads 20F are spaced apart in a direction perpendicular to the longitudinal direction of the bead 20F. Each bead 20F connects the outer circumference 73 of the base 7 and the outer end 55 of the inner panel 2. The bead 20F is the same as the configuration of the first bead 21 described above, except that it extends diagonally inward and forward. It is preferable that the beads 20F are arranged at equal pitches in a direction perpendicular to the longitudinal direction of the bead 20F when viewed in the thickness direction. The beads 20F may be arranged at unequal pitches in a direction perpendicular to the longitudinal direction of the bead 20F. It is preferable that the multiple beads 20F are arranged over substantially the entire width X area at the rear 1a of the automobile hood 1. Multiple beads 20F may be arranged only on the outer end side in the width direction X at the rear portion 1a.

[0111] <Seventh variation of bead arrangement (diagonal grid arrangement)> Figure 15(C) shows a seventh modified example of the bead arrangement. In this seventh modified example, beads 20E extending diagonally outward and beads 20F extending diagonally inward are arranged in a grid pattern. The configuration of bead 20E is the same as that of bead 20E shown in Figure 15(A). The configuration of bead 20F is the same as that of bead 20F shown in Figure 15(B).

[0112] <Modified unit (the unit's flange is a circular flange)> In the embodiments and modifications described above, the configuration in which the unit 9 of the overhanging structure 6 is polygonal in shape was described as an example. However, this is not required. For example, as shown in Figures 16(A) and 16(B), the unit may be a unit 9A formed in a circular shape by one subunit 10A. Figure 16 shows a modified example of the unit. Figure 16(A) is a schematic plan view of the main part. Figure 16(B) is a cross-sectional view of one unit 9A in Figure 16(A). The overhanging structure 6A has a configuration in which the units 9A are arranged in the closest possible order.

[0113] In each unit 9A, the vertical wall 12A is formed in a cylindrical or hollow frustoconical shape, and the flange 11A is formed in a circular shape. The vertical wall 12A and flange 11A may also be formed in an elliptical shape (a type of circular shape) in plan view. In the cantilevered structure 6A, the units 9A do not have to be arranged in the closest possible proximity, and other parts may be formed between adjacent units 9A, 9A.

[0114] Each unit 9A has one subunit 10A, and the subunit 10A has a flange 11A and a vertical wall 12A continuous with the flange 11A.

[0115] <Other variations> In the embodiments and modifications described above, the inner panel 2 and outer panel 3 were described as being formed from steel plates or aluminum alloy plates. However, this is not required. At least one of the inner panel 2 and outer panel 3 may be formed from a resin material such as glass fiber or carbon fiber. Alternatively, at least one of the inner panel 2 and outer panel 3 may be formed from a composite material of a metal material and a resin material. [Industrial applicability]

[0116] The present invention can be widely applied as an inner panel for an automobile hood, an automobile hood, and a method for manufacturing an automobile hood. [Explanation of symbols]

[0117] 1. Automotive hood 1a Rear of the inner panel 2 Inner Panel 3 Outer Panel 5. Outer perimeter of the inner panel 7 Pedestal 9.9A Unit 11,11A flange 12,12A vertical wall 20, 20A, 20B, 20D, 20E, 20F beads 55 Outer edge of inner panel 73 Outer circumference of the base 101 Suspension Tower (Vehicle Part) 200 Head Impactor (Object) D Distance (distance from vehicle parts to the bead) H bead height Y-direction (vehicle length direction) t2 plate thickness

Claims

1. It is an inner panel for the car hood, A base is positioned on the inside of the inner panel relative to the outer periphery of the inner panel, Multiple units, each including a vertical wall rising from the base and a flange continuous with the upper end of the vertical wall, At least one of the beads, which connects the outer ends of the inner panels in a direction perpendicular to the thickness direction of the inner panel, and which connects the outer periphery of the base to the outer end, Equipped with, The aforementioned beads are provided in multiple locations and are positioned on the rear side of the inner panel in the vehicle length direction of the vehicle on which the automobile hood is installed. The bead is formed in a shape that is convex upward or downward in the thickness direction of the inner panel of the automobile hood, and in a cross section perpendicular to the longitudinal direction of the bead, the height of each bead is 10 mm to 40 mm and the width is 10 mm to 40 mm. An inner panel for an automobile hood, wherein, when the automobile hood is installed on the vehicle, the plurality of beads are arranged such that, in a view of the inner panel in the thickness direction, the suspension tower of the vehicle is positioned between the plurality of beads.

2. The inner panel for an automobile hood according to claim 1, wherein the flange of each unit is polygonal or circular when viewed in the thickness direction of the inner panel.

3. The inner panel of an automobile hood according to claim 2, wherein a plurality of the aforementioned units are arranged in the closest possible proximity.

4. An inner panel for an automobile hood according to claim 1, which is made of a steel plate with a thickness of 0.3 mm to 0.6 mm.

5. An inner panel according to any one of claims 1 to 4, An automobile hood comprising: an outer panel positioned above the inner panel and joined to the flange.

6. A method for manufacturing an automobile hood according to claim 5, The aforementioned automobile hood is fabricated as a test hood, and under conditions in which a predetermined vehicle component is placed at a predetermined distance below the test hood, the impact value acting on the object when an impact load from an object is applied to the rear of the test hood is determined. A method for manufacturing an automobile hood, comprising forming the bead at a position set based on the relationship between the distance of the bead from the vehicle part and the impact value in a view of the inner panel in the thickness direction.

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