JP2009154595A - Automobile hood panel superior in pedestrian protective property - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an automobile hood panel superior in pedestrian protective property, capable of relieving restriction on selection of a material, by reducing an HIC value, even if a clearance between a hood panel and a rigid member such as an engine is reduced, by restraining deformation of the hood panel. <P>SOLUTION: This automobile hood panel is composed of an outer panel and an inner panel. The inner panel is provided with a recessed part having a cross-sectional shape of a substantially trapezoidal shape and having the bottom opposed in close vicinity to the outer panel. The first recessed part and the second recessed part are crossed with each other, and 2/3 or more up to a central part from an end part of a projection part surrounded by the first recessed part and the second recessed part, is a continuous surface, and a discontinuous part for preventing propagation of deformation is arranged at least in a part of the recessed part. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an automobile hood panel that is excellent in performance for protecting a pedestrian, particularly a pedestrian's head, that is, in pedestrian protection, when a pedestrian collides with an automobile.

  In recent years, protection of a pedestrian's head at the time of a collision between a pedestrian and a car is regarded as important, and studies on the structure of a hood panel for a car that has excellent pedestrian protection have been promoted. The performance of pedestrian protection is evaluated by a head injury criterion value (Head Injury Criteria, hereinafter referred to as “HIC value”) calculated by the following formula (1).

  For example, according to the current judgment standard, when a car collides at a speed of 40 km / h, the HIC value in a portion of 2/3 or more of the test area is 1000 or less, and the HIC value in other test areas is 2000. The following are required.

  As shown in FIG. 14, a conventional automobile hood panel is a structure in which an outer panel 1 and an inner panel 2 formed by press-molding a metal plate are joined. The bottom of the groove-like bone portion of the inner panel 2 is positioned on the side far from the outer panel, and a part of the portion adjacent to the outer panel is punched out for weight reduction.

  When a pedestrian's head collides with this automobile hood panel, the outer panel is first deformed, and then the inner panel is deformed to absorb the energy of the collision. At this time, in order to ensure pedestrian protection, it is necessary to prevent interference and contact between the pedestrian's head and a rigid member such as an engine.

  However, in the portion of the conventional hood panel shown in FIG. 14 where the bone portion of the inner panel does not exist, only the outer panel is present. Interference and contact with members are easy. The rigid member is a general term for members having high rigidity compared to the hood panel, such as an engine or suspension attachment portion, and having a high possibility of giving a large obstacle when colliding with the head.

  Therefore, conventionally, from the viewpoint of pedestrian protection, it has been important to prevent interference and contact between the hood panel and the rigid member when the pedestrian's head contacts the hood panel. However, as a countermeasure, if the distance between the hood panel and the rigid member, that is, the clearance is increased, the design of the vehicle body is limited.

  Therefore, as a technique that can secure pedestrian protection even if the clearance is reduced, as shown in FIG. 15, a hood panel has been proposed in which the cross section of the inner panel 2 has a corrugated shape and rigidity as a member is increased. (For example, patent document 1).

  However, even in this technique, if the kinetic energy given to the hood panel when the pedestrian's head collides is large, the possibility of contact with the rigid member is extremely high. Therefore, it is preferable to prevent the pedestrian's head from contacting the engine or the like, and it is necessary to secure a certain amount of clearance. In addition, since the inner panel has a corrugated cross section and is substantially parallel to one direction, there is a problem that the rigidity anisotropy of the panel is increased.

  On the other hand, as shown in FIG. 16, the head of the pedestrian is provided with a shape irregular portion that deforms locally when the inner panel and the rigid member come into contact with each other at the tip of the cone provided on the inner panel 2. A cone-type inner panel that suppresses the reaction force to the part has been proposed (for example, Patent Documents 2 and 3).

  However, if the shape of the protrusion is complicated, it may be difficult to form depending on the material. Further, even in this technique, when the clearance is small, the cone is crushed at the time of collision, and the possibility that the hood panel and the rigid member interfere and come into contact with each other increases.

JP 2003-205866 A JP 2003-54449 A JP 2005-186766 A

  The present invention makes it possible to reduce the clearance between a hood panel and a rigid member such as an engine by suppressing deformation of the hood panel when a pedestrian's head collides, and when the rigid member and the hood panel interfere with each other. Another object of the present invention is to provide a hood panel for automobiles that can reduce the HIC value by utilizing deformation of the inner panel and has excellent pedestrian protection.

  The present invention provides a conventional inner panel without a punched hole in the convex portion, the bottom of the concave portion is opposed to the outer panel, and the impact energy when the pedestrian's head collides is It was made based on the knowledge that it is possible to achieve both suppression of deformation of the hood panel and reduction of the HIC value when the head of the pedestrian collides, by preventing transmission to the part. The gist is as follows.

  (1) It consists of an outer panel and an inner panel, and the inner panel has a substantially trapezoidal cross-sectional shape, and has a recess facing the outer panel close to the outer panel. And a second concave portion intersecting with the first concave portion, and 2/3 or more from the end portion to the center portion of the convex portion surrounded by the first concave portion and the second concave portion is a continuous surface. A hood panel for an automobile having excellent pedestrian protection, wherein a discontinuous portion for preventing propagation of deformation is provided in at least a part of the recess.

(2) The discontinuity part which prevents propagation of a deformation | transformation was provided in the one end or both ends of the 2nd recessed part provided in the peripheral part of the inner panel. Excellent automotive hood panel.
(3) The discontinuity part which prevents propagation of a deformation | transformation was provided in the both ends of all the 2nd recessed parts of an inner panel, It is excellent in the pedestrian protection as described in said (1) or (2) characterized by the above-mentioned. Automotive food panel.
(4) In any one of the above (1) to (3), the first concave portion of the inner panel and the second concave portion provided in the peripheral portion and the central portion intersect in a crank shape. An automotive hood panel with excellent pedestrian protection.

(5) The automobile hood panel having excellent pedestrian protection according to any one of the above (1) to (4), wherein the planar shape of the convex portion of the inner panel is substantially polygonal.
(6) The automobile hood panel having excellent pedestrian protection according to any one of (1) to (5) above, wherein the inner panel has a continuous surface from the end to the center of the convex portion. .

(7) The hood panel for an automobile having excellent pedestrian protection according to any one of (1) to (6) above, wherein the width of the bottom of the recess of the inner panel is 10 to 100 mm.
(8) The hood panel for an automobile having excellent pedestrian protection according to any one of (1) to (7) above, wherein the depth of the recess of the inner panel is more than 20 mm and 50 mm or less.

(9) The pedestrian according to any one of (1) to (8) above, wherein the material of the outer panel and the inner panel is any one of steel, aluminum alloy, magnesium alloy, and titanium alloy. Automotive food panel with excellent protection.
(10) The automobile hood panel having excellent pedestrian protection according to (9) above, wherein the inner panel is made of an aluminum alloy and has a thickness of 0.6 to 1.5 mm.
(11) The automobile hood panel having excellent pedestrian protection according to any one of (1) to (8) above, wherein the material of the inner panel is a resin or a fiber reinforced resin.

  According to the present invention, the clearance between the automobile hood panel and the rigid member such as the engine can be reduced, and the design limit of the bonnet is reduced. For example, the relative height of the outer panel in the automobile body can be reduced, and the degree of freedom for the design can be increased. Even if the hood panel and the rigid member interfere when the head collides, the HIC value can be reduced, and pedestrian protection can be greatly improved compared to the conventional panel. it can.

  In addition, as the material of the inner panel, a slightly inferior formable material can be used. For example, if an aluminum alloy plate is used, it is possible to achieve both weight reduction of the hood panel and pedestrian protection. Become. Therefore, according to the present invention, it is possible to provide an automobile excellent in fuel consumption performance and exercise performance, as well as pedestrian protection, and the industrial contribution is extremely remarkable.

  The present inventors have provided a hood panel provided with an inner panel of the conventional type shown in FIG. 14, the wave type shown in FIG. 15, and the cone type shown in FIG. 16 (hereinafter referred to as a conventional panel, a wave type panel, and a cone type panel, respectively). The HIC value and the head displacement amount were calculated by numerical analysis assuming the following cases 1 to 4. Note that the head displacement is the amount of movement in the vertical direction from when the head contacts the outer panel until it stops.

Case 1: The head collides with the bone, and the hood panel does not contact the rigid member.
Case 2: The head collides outside the bone, and the hood panel does not contact the rigid member.
Case 3: The head collides with the bone, and the hood panel contacts the rigid member.
Case 4: The head collides outside the bone, and the hood panel contacts the rigid member.

  Here, the collision on the bone part means that the impactor collides with the bone part of the conventional panel, the wave peak near the outer panel in the corrugated panel, and the apex of the cone type panel just above the apex of the cone. is there. In addition, the collision outside the bone part is a collision between the bone part and the bone part in the conventional type panel, in the case of the wave type panel, when colliding with the peak part of the wave far from the outer panel, in the cone type panel, This is a case where the collision occurred avoiding the apex of the cone.

As a result of numerical analysis, it was found that the qualitative superiority or inferiority of the HIC value in each case due to the structure of the food panel was as follows.
Cases 1 and 2: Almost the same for conventional panels, corrugated panels, and cone panels.
Case 3: The conventional panel is superior to the corrugated panel and the cone panel.
Case 4: The wave type panel, the conventional type panel, and the cone type panel have not reached the standard value.

  First, in the case of Case 3, the present inventors considered the reason why the conventional panel has excellent pedestrian protection. As a result, when the head collides with the bone part of the conventional panel, as shown in FIG. 1, the bone part in contact with the rigid member is supported and the interference between the head and the rigid member is prevented. Got.

  Next, the present inventors considered the reason why the pedestrian protection of the conventional panel is inferior in case 4. In the case of the case 4 in the case of the conventional panel, as shown in FIG. 2, since the inner panel is not restrained against deformation in the plane direction, the outer panel deforms and contacts the rigid member. Therefore, even if the inner panel is used without being punched and the strength of the hood panel is increased, the deformation of the outer panel cannot be suppressed, and the pedestrian protection is not significantly improved.

  Therefore, the present inventors have studied a structure of a hood panel that can suppress the deformation of the outer panel and protect the pedestrian head when the inner panel and the rigid member are in contact with each other in the case 4. As a result, as shown in FIG. 17, if the bottom of the concave portion is opposed to the outer panel without providing a punching hole in the convex portion of the conventional inner panel, when the inner panel contacts the rigid member, It turns out that reaction force occurs. In addition, FIG. 17 is a perspective view of the surface facing the outer panel, and the depression is a convex portion.

  Furthermore, the hood panel shown in FIG. 17 was also numerically analyzed and compared with a conventional panel, a corrugated panel, and a cone panel. As a result, it was found that the case where the inner panel and the rigid member are not in contact, that is, cases 1 and 2, are equivalent to the conventional panel, the corrugated panel, and the cone panel. In contrast, when the inner panel and the rigid member are in contact, that is, the case 3 is equivalent to the conventional panel, and the case 4 is a pedestrian superior to any of the conventional panel, the corrugated panel, and the cone panel. It was found to have protective properties.

  Furthermore, the present inventors paid attention to the head displacement in cases 1 and 2 where the hood panel does not interfere with or contact the rigid member. As a result of numerical analysis, it was found that the head displacement amount of the inner panel shown in FIG. 17 is inferior to that of the conventional panel, the corrugated panel, and the cone panel. Therefore, the present inventors examined the cause of the deformation of the inner panel shown in FIG. 17 when the hood panel does not interfere with or contact the rigid member, that is, the head displacement amount is inferior to other structures. The following findings were obtained.

  First, in the a-a ′ cross section (cross section a) of the inner panel shown in FIG. 17, as shown in FIG. 18 a, the concave portion of the inner panel facing the outer panel is constrained by the convex portion. For this reason, it is difficult to deform at a site such as the cross section a. However, in the zz ′ cross section (cross section z) of the inner panel shown in FIG. 17, as shown in FIG. 18b, the bottom of the concave portion of the inner panel adjacent to the outer panel is substantially communicated in the width direction of the panel. ing.

  Therefore, since the inner panel is easily bent at a portion such as the cross section b, the deformation, that is, the head displacement amount increases.

  Based on this knowledge, the present inventors examined a structure capable of suppressing the deformation of the inner panel when the pedestrian's head collides. As a result, it was found that the amount of head displacement can be suppressed by providing a discontinuous part in a part of the recess of the inner panel. An example of the inner panel of the present invention is shown in FIGS. 3a to 3c are perspective views of the surface facing the outer panel, in which the depressions are convex portions.

  Furthermore, the HIC value and the head displacement of the hood panel shown in FIGS. 3a to 3c were obtained by numerical analysis. As a result, the HIC value when the hood panel interferes with the rigid member is superior to the conventional panel, the corrugated panel, and the cone panel, and is equivalent to the inner panel (referred to as an improved panel) shown in FIG. It was confirmed.

  It was also found that the head displacement when the hood panel and the rigid member do not interfere is superior to that of the improved panel, and equal to or greater than that of the conventional panel, wave panel, and cone panel. Furthermore, it turned out that it is excellent in the order of FIG. 3c, FIG. 3b, and FIG. 3a about the head deformation amount of the hood panel shown to FIG.

  Sectional views of the automobile hood panel of the present invention (hereinafter referred to as “the hood panel of the present invention”), that is, the sections be indicated by broken lines in FIGS. 3 a to 3 c are schematically shown in FIGS. In addition, the cross section a of this invention food panel shown to FIG. 3 a is the same as that of FIG. 18 a.

  The lower side of the panel shown in FIGS. 4 a to 4 d is the outer panel 1, and the upper inner panel 2 has a concavo-convex portion, the side far from the outer panel 1 is a convex portion 21, and a groove-shaped concave portion 22 (first concave portion). 22a, the bottom of the second recess 22b) is close to the outer panel 1. The end of the outer panel 1 is bent and joined to the inner panel 2. The bottom surface of the recess 22 (the first recess 22a and the second recess 22b) of the inner panel 2 and the outer panel 1 may be in contact with each other.

  When the pedestrian head collides with the hood panel of the present invention, the outer panel comes into contact with the bottom of the recess of the inner panel. At this time, the kinetic energy of the collision given to the inner panel propagates over a wide range in the plane direction via the concave and convex portions of the inner panel. Furthermore, when the kinetic energy of the collision is large, the hood panel comes into contact with a rigid member such as an engine.

  Further, as shown in FIG. 3a, if a structure is provided in which a discontinuous portion is provided in at least a part of the recess so that the kinetic energy of the collision is not transmitted to the peripheral portion of the panel, the deformation of the panel reaches the peripheral portion Can be prevented. Thereby, it becomes possible to suppress the deformation of the panel to be equal to or higher than that of the conventional panel, and the head displacement can be suppressed.

  3a to 3c show a mode in which the front-rear direction is the first recess and the width direction is the second recess, but the width direction is the first recess, and the front-rear direction is the second recess. It is good. In any case, if a discontinuous portion is provided at one end of the concave portion, it is possible to prevent the deformation from being transmitted, which is effective in suppressing the amount of head deformation.

  Furthermore, in order to prevent the deformation from being transmitted to the peripheral portion of the panel, it is preferable to provide a discontinuous portion at one end or both ends of the concave portion arranged in the peripheral portion of the panel, particularly the second concave portion.

  Further, since increasing the number of discontinuous portions of the recesses is effective in suppressing the deformation of the panel, as shown in FIG. 4b, it is preferable to provide at both ends of all the second recesses 22b. Furthermore, although the aspect which the 1st recessed part extended | stretched continuously is shown in FIG. 3 a-FIG. 3 c, you may provide a discontinuous part.

  The second recesses may be arranged in a straight line as shown in FIGS. 3a and 3b. However, in order to suppress the deformation of the panel, the second recesses in the peripheral part and the central part are provided. It is preferable to arrange so as not to be linear. That is, it is preferable to arrange the second concave portion and the first concave portion in the peripheral and central portions of the panel in a crank shape.

  For example, in the arrangement as shown in FIG. 3c, the second concave portion arranged in the peripheral portion of the panel and the intersection of the first concave portion, the second concave portion arranged in the center portion of the panel, and the first Since the intersection of the recesses does not match, it is effective for suppressing deformation.

  In addition, the second concave portion in the peripheral portion of the panel may be arranged obliquely without making the second concave portion in the peripheral portion of the panel parallel to the second concave portion in the central portion of the panel. In addition, the 1st recessed part and the 2nd recessed part may be extended | stretched linearly, for example, as shown to FIG. Further, as shown in FIG. 5b, the first recess may be disposed obliquely and a step may be provided at the intersection with the second recess.

  Next, the reason why the hood panel of the present invention can reduce the HIC value when contacting and interfering with a rigid member will be described.

  As shown in FIG. 6, when the pedestrian head 3 collides with the vicinity of the recess 22 of the inner panel, the recess 22 in contact with the rigid member 4 serves as a support. Therefore, like the conventional panel shown in FIG. 1, contact between the head and the rigid member can be prevented, and therefore, the pedestrian protection is superior to the corrugated panel and the cone panel.

  Further, as shown in FIG. 7, when the pedestrian head 3 collides between the concave portions of the inner panel, the convex portion 21 contacting the rigid member 4 restrains the deformation of the concave portion 22 in the plane direction. Therefore, a large reaction force is generated. However, when the recess extends substantially parallel to one direction, for example, when the recess has only a recess parallel to the front-rear direction of the hood panel, the restraint by the protrusion 21 is limited to the width direction.

  Therefore, in order to obtain excellent pedestrian protection, the convex portion 21 needs to be surrounded by the concave portion 22. Moreover, since the kinetic energy provided to the convex part per piece can be made small if there are two or more convex parts 21, it is more preferable.

  In order to maximize the reaction force when the convex portion comes into contact with the rigid member, it is preferable that the convex portion is not provided with a punching hole and the surface from the end portion to the central portion is continuous. This minimizes the HIC value, but the convex portion may be provided with a punched hole for the purpose of absorbing engine sound, reducing the weight of the hood panel, and the like.

  However, in this case, it is necessary to provide a restriction on a region where the punching hole at the center of the convex portion can be provided (hereinafter referred to as a punchable region). In order to ensure the pedestrian protection of the panel, it is necessary that the punchable area has a similar shape with the center of the convex portion as a reference, and the size is within 1/3 of the convex portion.

  That is, it is necessary to make 2/3 or more from the end part of the convex part to the central part a continuous surface. Thereby, when the convex part of an inner panel contacts a rigid member, the deformation | transformation to the plane direction of the recessed part 22 is fully restrained similarly to the panel which does not provide the punching hole shown in FIG. Therefore, even if a punching hole whose size is 1/3 of the convex portion is provided in the central portion of the convex portion, a large reaction force is generated, and excellent pedestrian protection is obtained.

  8a and 8b show the punchable area. 8a is a cross-sectional view and FIG. 8b is a plan view. FIG. 8 shows an example in which the planar shape of the convex portion is a quadrangle. The planar shape of the convex portion is not limited to a square, and can be punched even when it is a polygon such as a triangle or a hexagon. It suffices if the region has a similar shape to the planar shape of the convex portion.

  The position, shape, and size of the punching hole can be freely set as long as they are provided inside the punchable region 24. For example, as shown in FIGS. 9a and 9b, the entire punchable region may be punched, and as shown in FIGS. 10a and 10b, a plurality of small diameter punching holes may be provided in the punchable region.

  In addition, the inner panel may be provided with holes for the purpose of waste liquid at the time of surface treatment in the manufacturing process and holes for passing wiring and piping of automobile devices, for example, tubes for supplying window washer liquid. . Therefore, it is possible to provide a hole with a diameter of 1 to 10 mm at an arbitrary portion of the convex portion and the concave portion of the inner panel with an aperture ratio of 5% or less.

  The aperture ratio is a numerical value expressed as a percentage of the ratio of the total area of the holes to the surface area of the inner panel excluding the punched holes provided in the punchable area.

  The cross-sectional shape of the concave portion needs to be substantially trapezoidal as shown in FIGS. 11 and 12 because the concave portion easily deforms on a curved surface such as a corrugated shape or a cone. Note that the cross-sectional shape of the recess may be rectangular. Moreover, since the cross-sectional shape of the concave portion is substantially trapezoidal, the cross-sectional shape of the convex portion is preferably also substantially trapezoidal, but the surface far from the outer panel is not limited to a flat surface, and may be a curved surface having a curvature. Good.

  11 and 12, the angle θ of the side surface 23 of the recess is preferably 40 to 90 °. This is because when the angle θ of the side surface 23 of the recess is less than 40 °, the contact between the projection 21 and the rigid member becomes insufficient when the head of the pedestrian collides directly above the recess 22. This is because the reaction force may not occur.

  On the other hand, when the inner panel is obtained by press molding, it is difficult for the angle θ of the side surface 23 of the recess to exceed 90 °, and as the angle θ approaches 90 °, a material with higher moldability is required. In addition, if the angle θ of the bottom of the recess is reduced, press molding is facilitated, but the amount of kinetic energy absorbed by plastic deformation when the recess 22 is crushed is reduced, so the angle of the side surface 23 of the recess is 50 ° or more. It is preferable to do.

  Compared to the hood panel of the present invention, the concave shape of the cone type panel and the concave shape of the corrugated panel are curved, so that it easily deforms when it comes into contact with the rigid member, and collides with the rigid member of the pedestrian head. The effect to prevent is small. Further, in the cone-type panel, the depressions are not connected to each other, and the kinetic energy resulting from the collision of the pedestrian head is concentrated locally.

  In addition, although the cone type panel which connected the hollow with the bead is proposed, since the height of a bead is lower than a hollow, the effect of dispersion | distribution of a kinetic energy and the absorption of the kinetic energy by plastic deformation is not enough. On the other hand, the corrugated panel has insufficient pedestrian protection since the extending direction of the corrugated grooves is limited to one direction.

  Accordingly, the groove-like recesses of the inner panel intersect and are preferably connected except for the discontinuous portions, and the planar shape of the projections surrounded by the recesses is preferably a polygon. Thereby, the kinetic energy added to the inner panel by the collision of the pedestrian head is dispersed in a wide range, and the pedestrian protection is further improved.

  The planar shape of the convex portion is not limited to a quadrangle, and may be a triangle or a hexagon, or a combination thereof. In addition, not only rectangles, but also squares, parallelograms, rhombuses, trapezoids, etc., and any triangles, such as isosceles triangles, right triangles, etc. It may be a triangle.

  Also, the size of the planar shape of the convex portions need not be the same, and depending on the shape of the hood panel, as shown in FIGS. 13a to 13c, quadrangles of different sizes, combinations of quadrangles and trapezoids, etc. Can be appropriately selected. In addition, in FIG. 13a-FIG. 13c, illustration of the discontinuous part of a recessed part is abbreviate | omitted.

  Further, the shape of the portion where the concave portions intersect may be an arc shape in order to avoid stress concentration, and the radius of curvature is preferably 100 mm or more. The shape between the intersections of the recesses is preferably linear, but may be arcuate.

  When the clearance between the hood panel and the rigid member is small, for example, when the clearance is 75 mm or less, the impact absorption may be insufficient when the pedestrian head collides with the vicinity of the recess. For such a problem, it is effective to limit the width of the bottom of the recess of the inner panel and the height of the recess.

  As for the width W of the bottom of the recessed part of an inner panel, 10-100 mm is preferable. This is because if the width W of the bottom of the recess of the inner panel is less than 10 or more than 100 mm, the impact absorption may be insufficient when the pedestrian head collides with the vicinity of the recess. . In addition, when the press formability of a raw material is considered, it is preferable that the space | interval of recessed parts is 2 times or more of the width W of the bottom of a recessed part.

  Moreover, it is preferable that the height H of the recessed part of an inner panel is more than 20 mm. This is because if the height H of the recess is small, the pedestrian head is likely to come into contact with the rigid member. In addition, although there is no restriction | limiting in particular in the upper limit of the height H of a recessed part, when press-molding an inner panel, it is difficult to make it more than 50 mm, for example, when the moldability of a raw material is inferior like an aluminum alloy. , 35 mm or less is preferable.

  The material of the inner panel can be appropriately selected from steel, aluminum alloy, magnesium alloy, and titanium alloy. Among these, from the viewpoint of weight reduction, any of an aluminum alloy, a magnesium alloy, and a titanium alloy is preferable. The same applies to the outer panel, and it is preferable to use the same material as the inner panel.

  Furthermore, an aluminum alloy is optimal in view of manufacturing costs. Similarly, the outer panel is preferably made of an aluminum alloy. When an aluminum alloy is used as the material for the food panel, the inner panel has excellent moldability, and the outer panel has excellent paint bake hardenability (hereinafter referred to as BH property). It is preferable to select an optimum one according to the above.

  In the case of an aluminum alloy, it is preferable to use an Al—Mn-based 3000-based alloy, an Al—Mg-based 5000-based alloy, or an Al—Mg—Si-based 6000-based alloy. When formability is required, a 5000 series alloy containing 3 to 6%, preferably 4 to 5% of Mg is preferable.

  Since the 6000 series alloy exhibits BH properties, when strength is required, for example, a 6000 series alloy containing 0.2 to 1.2% Mg and 0.5 to 1.5% Si. Is preferred. The 6000 series alloy may contain 0.1 to 1.5% of Cu.

  In order to develop the BH property of the 6000 series alloy, the final solution treatment in the production process is performed at 480 ° C. or higher, and then cooled, wound at 70 to 150 ° C., and held at that temperature range for about 5 hours. It is preferable to perform preliminary aging treatment. In addition, although the upper limit of solution treatment temperature should just be less than the temperature which a liquid phase produces | generates, when manufacturing property is considered, 600 degrees C or less is preferable.

  On the other hand, in order to improve the formability of the 6000 series alloy, it is contrary to the BH property, but after the solution treatment, it is cooled within a temperature range from room temperature to 70 ° C. at a cooling rate of 10 ° C./s or more. The temperature is preferably maintained for 1 to 100 hours.

  In addition, when the weight reduction of a food panel is the most important subject, the raw material of an inner panel is good also as resin, and it is preferable that it is a fiber reinforced resin from a viewpoint of intensity | strength. The same applies to the outer panel, and it is preferable to use the same material as the inner panel.

  When the material of the food panel of the present invention is an aluminum alloy, the thickness of the inner panel is preferably in the range of 0.6 to 1.5 mm. When the pedestrian's head collides between the recesses, it is preferable to increase the rigidity of the recesses by increasing the thickness of the inner panel to 0.6 mm or more in order to suppress deformation of the outer panel.

  On the other hand, when the head of the pedestrian collides with the vicinity of the concave portion, the shock is absorbed by deformation of the inner panel. Therefore, when the thickness of the inner panel increases, the rigidity increases and the shock absorption increases. However, if the plate thickness exceeds 1.5 mm, the deformation may be too small and the HIC value may increase. Therefore, the plate thickness of the inner panel is preferably 1.5 mm or less. Furthermore, in order to effectively reduce the weight of the inner panel, the thickness of the inner panel is preferably set to 1.2 mm or less.

  When the material of the inner panel is an aluminum alloy, the material of the outer panel is also preferably an aluminum alloy. If the plate thickness of the outer panel is too thin, the deformation becomes large, and if it is too thick, the rigidity increases and the pedestrian protection may be impaired. From the viewpoints of weight reduction, moldability, manufacturing cost, and pedestrian protection, the thickness of the outer panel is preferably 0.8 to 1.5 mm.

  The inner hood shown in FIG. 3 has a total length of 900 to 1200 mm, a total width of 1200 to 1600 mm, a recess bottom width of 20 mm, a recess depth of 32 mm, and a recess so that the protrusion has a square shape. Assuming a panel, numerical analysis equivalent to an impactor test for adults with pedestrian head protection standards was performed.

  For comparison, the same numerical analysis was performed on the conventional panel shown in FIG. 14, the corrugated panel shown in FIG. 15, the cone panel shown in FIG. 16, and the improved panel shown in FIG.

  In other words, the analysis when the impactor with a diameter of 165 mm and the weight of 4.5 kg was collided at a speed of 32 km / h at an angle of 65 ° was performed with the analysis code of the general-purpose dynamic explicit method. Asked. About the collision position and interference with a rigid member, the conditions of the said cases 1-4 were assumed.

  The distance between the outer surface of the outer panel of each hood panel and the convex portion of the inner panel is constant at 32 mm, the material is made of a 6000 series aluminum alloy for body panels for automobiles, and the thickness of the outer panel is 1.0 mm. The inner panel thickness was 0.8 mm.

  However, the conventional panel (bone type) has a large reduction hole, and if the thickness of the inner panel is 0.8 mm, the weight is small and disadvantageous. Therefore, the thickness of the inner panel is set to 1.0 mm so that the weight is equal to that of other panels. The distance (clearance) from the outer panel to the rigid member was 85 mm.

  The characteristic values of the 6000 series aluminum alloy used for the analysis were obtained by producing in advance a product containing 0.6% Mg and 1.0% Si and the balance being Al and performing a tensile test.

  Table 1 shows the HIC values of the panel of the present invention obtained by numerical analysis assuming cases 1 to 4, together with the analysis results of the conventional panel, wave panel, cone panel, and improved panel.

  As shown in Table 1, in the case 1 and the case 2 that do not collide with the rigid member, the HIC value is 1000 or less in any structure, and the pedestrian protection is good. Moreover, the difference by structure is not remarkable.

  On the other hand, in case 3, the HIC value of the panel of the present invention, the conventional panel and the improved panel is smaller than that of the corrugated panel and the cone panel, and the pedestrian protection is excellent. This is because the bone portion is supported by the conventional panel, and the concave portion is supported by the panel of the present invention and the improved panel, thereby preventing interference between the head and the rigid member.

  Further, in case 4, the HIC value of the panel of the present invention and the improved panel was smaller than those of other panels, and it was found that the pedestrian protection was most excellent. This is considered to be because in the panel of the present invention and the improved panel, the deformation of the concave portion was restrained by the convex portion, and the kinetic energy due to the collision of the head was effectively absorbed.

  The same analysis was performed to investigate the shape of the projections of the panel of the present invention, the influence of the formation of punched holes, and the influence of the thickness and material of the aluminum alloy plate as the material. As a result, with respect to the formation of the punched hole, the deterioration of the HIC value is 10% with respect to the influence of the punched hole whose size is 1/3 of the convex part and whose shape is similar to that of the convex part. It was confirmed that

  Moreover, also about the influence of board thickness and material, if the recessed part and the convex part satisfy the conditions of this invention, it was confirmed that the HIC value does not exceed 1000 and it is excellent in pedestrian protection.

  Table 2 shows the head displacement amount of the panel of the present invention obtained by numerical analysis assuming cases 1 to 4 together with the analysis results of the conventional panel, the corrugated panel, the cone panel, and the improved panel. As shown in Table 2, the amount of head displacement of the panel of the present invention in Cases 1 and 2 that do not collide with rigid members is smaller than that of the other panels. I found it excellent.

  In the panel of the present invention, it is considered that the amount of displacement of the head can be reduced because the discontinuity is provided in the concave portion to suppress the deformation of the panel.

  The overall length, full width, and size of the rigid member interference portion are the same as those in Example 1, and the heads of the plate thicknesses and materials shown in Tables 3 and 4 are used under the conditions of Cases 1 to 4 above. A numerical analysis equivalent to an impactor test for adults based on the pedestrian head protection standard was performed. Tables 3 and 4 show the HIC value and head displacement, respectively.

  Table 5 shows the 0.2% proof stress, tensile strength, and BH characteristics of the inner panel and outer panel materials shown in Tables 3 and 4. The tensile properties of the aluminum alloys shown in Table 5 were measured according to JIS Z 2241 using tensile test pieces prepared according to JIS Z 2201. The yield strength after BH is the amount of BH measured with a pre-strain of 2%, an aging temperature of 170 ° C., and an aging time of 20 minutes, as in the paint bake hardening test method described in the annex of JIS G 3135. .

  The component composition of the 6000 series alloy is 0.6% Mg, 1.0% Si, the balance Al and inevitable impurities, and the composition composition of the 3000 series alloy is 1.2% Mn, 1.0% Mg. The balance Al and inevitable impurities are included, and the component composition of the 5000 series alloy is 4.5% Mg, the balance Al and inevitable impurities.

  The 6000 series alloy was produced by both the production process for developing BH properties and the production process for improving formability. That is, the production process for developing the BH property is a method in which after the solution treatment is performed at 480 to 600 ° C., the solution is cooled and wound up at 70 to 150 ° C. or less, and the preliminary aging treatment is performed for about 5 hours.

  Moreover, the manufacturing process which improves a moldability is the method of cooling to room temperature and 70 degrees C or less after performing solution treatment at 480-600 degreeC, and hold | maintaining and heat-processing for 1 to 100 hours. In addition, 3000 series alloy and 5000 series alloy were manufactured by the conventional method.

  As shown in Table 3, it can be seen that the HIC value is less than 1000 for any material and plate thickness, and the pedestrian protection is excellent. In case 1 and case 2, as the plate thickness increases, the weight and rigidity of the panel increase, so the HIC value tends to increase. In particular, the influence of the thickness of the outer panel on which the impactor first collides is large. Further, in the case 3, since the deformation in the vicinity of the concave portion is suppressed by increasing the thickness of the inner panel and the outer panel and increasing the strength of the material, the HIC value is increased.

  On the other hand, in the case 4, the reaction force associated with the deformation of the panel increases due to the increase in the thickness of the inner panel and the outer panel and the increase in the material, so that the HIC value decreases. Moreover, as shown in Table 4, although the change in the amount of displacement of the head due to the material and the plate thickness is small, as with the HIC value, the deformation of the panel is suppressed as the plate thickness increases and the material strength increases. The amount of displacement has decreased.

It is a figure which shows typically the collision of the head near the bone | frame part of the conventional food panel. It is a figure which shows typically the collision of the head outside the bone part of the conventional food panel. It is a figure which shows typically an example of the food panel of this invention. It is a figure which shows typically another example of the food panel of this invention. It is a figure which shows typically another example of the food panel of this invention. It is a figure which shows the cross section of an example of the food panel of this invention. It is a figure which shows the cross section of another example of the food panel of this invention. It is a figure which shows the cross section of another example of the food panel of this invention. It is a figure which shows the cross section of another example of the food panel of this invention. It is a figure which shows typically an example of the recessed part in the inner panel of this invention. It is a figure which shows typically another example of the recessed part in the inner panel of this invention. It is a figure which shows typically the collision of the head to the recessed part vicinity of the food panel of this invention. It is a figure which shows typically the collision of the head outside the recessed part of the food panel of this invention. It is a figure which shows typically the cross section of the punchable area | region. It is a figure which shows typically the plane of a punchable area | region. It is a figure which shows the plane of an example of the inner panel of this invention which made the punchable area | region the punching hole. It is a figure which shows the cross section of an example of the inner panel of this invention which made the punchable area | region the punching hole. It is a figure which shows the plane of an example of the inner panel of this invention which provided the small diameter punching hole in the punchable area | region. It is a figure which shows the cross section of an example of the inner panel of this invention which provided the small diameter punching hole in the punchable area | region. It is a figure which shows a part of cross section of an example of the inner panel of this invention. It is a figure which shows a part of cross section of another example of the inner panel of this invention. It is a figure which shows the plane of an example of the inner panel of this invention. It is a figure which shows the plane of another example of the inner panel of this invention. It is a figure which shows the plane of another example of the inner panel of this invention. It is a figure which shows typically the cross section of the conventional food panel. It is a figure which shows typically the cross section of the conventional corrugated food panel. It is a figure which shows typically the cross section of the conventional cone type food panel. It is a figure which shows an improved type food panel typically. It is a figure which shows typically the cross section a of an improved type food panel. It is a figure which shows typically the cross section z of an improved food panel.

Explanation of symbols

Reference Signs List 1 outer panel 2 inner panel 21 convex portion 22 concave portion 22a first concave portion 22b second concave portion 23 surface of the concave portion 24 discontinuous portion of the concave portion 25 punchable area 26 punched hole 3 head (impactor)
4 Rigid members

Claims (11)

  The inner panel is formed of an outer panel and an inner panel. The inner panel has a substantially trapezoidal cross-sectional shape, and a bottom has a recess facing the outer panel close to the outer panel. The recess has a first recess and the first recess. 2/3 or more from the end part of the convex part surrounded by the first concave part and the second concave part to the center part is a continuous surface. A hood panel for automobiles excellent in pedestrian protection, characterized in that a discontinuous portion for preventing propagation of deformation is provided in at least a part of a recess.   The hood for automobiles with excellent pedestrian protection according to claim 1, wherein a discontinuous portion for preventing propagation of deformation is provided at one or both ends of the second recess portion provided in the peripheral portion of the inner panel. panel.   The hood panel for an automobile with excellent pedestrian protection according to claim 1 or 2, wherein discontinuous portions for preventing propagation of deformation are provided at both ends of all the second recesses of the inner panel.   The pedestrian according to any one of claims 1 to 3, wherein the first concave portion of the inner panel and the second concave portion provided in the peripheral portion and the central portion intersect in a crank shape. Automotive food panel with excellent protection.   The planar shape of the convex part of an inner panel is a substantially polygon, The food panel for motor vehicles excellent in the pedestrian protection of any one of Claims 1-4 characterized by the above-mentioned.   The hood panel for an automobile having excellent pedestrian protection according to any one of claims 1 to 5, wherein the inner panel has a continuous surface from an end portion to a central portion.   The width | variety of the bottom of the recessed part of an inner panel is 10-100 mm, The food panel for motor vehicles excellent in the pedestrian protection of any one of Claims 1-6 characterized by the above-mentioned.   The depth of the recessed part of an inner panel is more than 20 mm and 50 mm or less, The food panel for motor vehicles excellent in the pedestrian protection of any one of Claims 1-7 characterized by the above-mentioned.   The material for the outer panel and the inner panel is any one of steel, an aluminum alloy, a magnesium alloy, and a titanium alloy, and is excellent in pedestrian protection according to any one of claims 1 to 8. Automotive food panel.   The hood panel for automobiles according to claim 9, wherein the inner panel is made of an aluminum alloy and has a thickness of 0.6 to 1.5 mm.   The food panel for automobiles according to any one of claims 1 to 8, wherein the material of the inner panel is resin or fiber reinforced resin.

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