JP2005193871A - Hood structure for automobile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hood structure for an automobile capable of enhancing impact absorption characteristic by effectively resisting to stress applied by impact load while suppressing increase of vehicle body weight as much as possible. <P>SOLUTION: A pair of main frames 7, 7 provided at a back side of a hood skin 2 is arranged so as to be crossed each other at an upper position of a cylinder head cover and is formed in a main stress axis X direction relative to input load. A pair of V-shape sub-frames 8 is provided so as to clamp the intersection part 10 of the respective main frames 7. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an automobile hood structure.

As a hood structure for automobiles, a cup cone-shaped projection is placed on the back of the hood to optimize the amount of head intrusion so that uniform shock absorption characteristics can be obtained at any position on the hood. Yes (see, for example, Patent Document 1). In addition, there is a type in which a reaction force characteristic is controlled by partially forming a hood frame provided on the back surface of the hood to have a closed cross-sectional structure, and the hood frame cross section is crushed to perform shock absorption (see, for example, Patent Document 2).
JP 2003-191865 A Japanese Patent No. 3120658

However, in the former case, the amount of head penetration can be optimized by the cup-cone-shaped protrusion, but since the holed portion is blocked, the weight of the hood increases accordingly and the weight of the vehicle body increases. There is a problem of going against fuel efficiency improvement.
In the latter case, in order to absorb the energy by crushing the cross section of the hood frame, it is necessary to form a closed cross-section structure portion in a wide range, and as a result, there is a problem that an increase in the weight of the vehicle body cannot be avoided.

  Therefore, the present invention provides an automobile hood structure that can effectively resist the stress acting by the impact load and enhance the shock absorption characteristics while suppressing the increase in the weight of the vehicle body as much as possible.

In order to achieve the above object, the invention described in claim 1 includes a pair of main frames (for example, the main frame 7 in the embodiment) provided on the back side of the hood skin (for example, the hood skin 2 in the embodiment). Arranged so as to cross each other above the high-rigidity parts (for example, the cylinder head cover 11 in the embodiment), and this main frame is formed in the direction of the main stress axis (for example, the main stress axis X in the embodiment) with respect to the input load. A pair of V-shaped sub-frames (for example, sub-frame 8 in the embodiment) is provided so as to sandwich the intersection (for example, the intersection 10 in the embodiment) of each main frame.
By configuring in this way, when the hood tries to bend and deform due to the applied input load, the hood prevents the hood from bottoming out on the high-rigidity component against the load in the direction in which the hood bends, and Since the main frame is arranged in the direction of the main stress axis with respect to the input load acting on the hood, it is effective against the stress with the hood skin in a shearing direction that is advantageous in strength over the installation length direction of the main frame Can compete against each other.

The invention described in claim 2 is characterized in that a mass material (for example, the tape stiffener 5 in the embodiment) is provided on the back side of the hood skin at a position centering on the intersection of the main frame. .
With this configuration, it is possible to increase the impact deceleration at the initial stage of the collision.

The invention described in claim 3 is characterized in that a part of the V-shaped subframe is formed in another main stress axis direction corresponding to the main frame formed in the main stress axis direction.
With this configuration, the subframe can effectively counter the stress caused by the input load with the hood skin in a shear direction that is advantageous in strength over the longitudinal direction.

According to a fourth aspect of the present invention, at least the hood skin and the main frame form a closed cross-section structure portion (for example, the closed cross-section structure portion 9 in the embodiment), and the closed cross-section structure portion can be crushed and deformed. It is characterized by.
With this configuration, even if the hood finally comes into contact with, for example, a high-rigidity part, it is possible to absorb impact energy with a short stroke while collapsing the closed cross-section structure from that stage.
Further, the closed cross-section structure portion formed between the main frame and the hood skin can counteract the bending deformation of the hood and increase the impact deceleration in the middle of the collision.

The invention described in claim 5 is characterized in that a sealer (for example, the mastic sealer 22 in the embodiment) is applied between the main frame and the hood skin with a portion closest to the high-rigidity part as a center. To do.
By comprising in this way, the deformation | transformation of the closed cross-section structure part formed between the main frame and the food skin by the sealer apply | coated between the main frame and the food skin can be suppressed.

According to the first aspect of the present invention, when the hood tries to bend and deform due to the applied input load, the hood prevents the hood from bottoming out on the high-rigidity part against the load in the direction in which the hood curves the hood. In addition, since the main frame is arranged in the principal stress axis direction with respect to the input load acting on the hood, the main frame is disposed between the hood skin and the hood skin in a shearing direction advantageous in strength over the installation length direction of the main frame. There is an effect that it can effectively resist stress, and thus can enhance the shock absorption characteristics.
Further, there is an effect that it is possible to contribute to weight reduction of the vehicle body as compared with the case where the main frame and the sub frame are provided over the entire back surface of the hood skin.

  According to the second aspect of the present invention, since it is possible to increase the impact deceleration at the initial stage of the collision, the stroke amount is reduced by that amount and the energy is absorbed until reaching the bottom. There is an effect that can be reduced.

  According to the third aspect of the present invention, since the subframe can effectively resist the stress caused by the input load with the hood skin in a shear direction that is advantageous in strength over the longitudinal direction, Similarly, there is an effect that the shock absorption characteristics can be enhanced.

According to the invention described in claim 4, even if the hood finally comes into contact with, for example, a heavy object, impact energy can be absorbed with a short stroke while collapsing the closed cross-section structure from that stage. Is effective in absorbing impact loads to the end.
In addition, the closed cross-section structure formed between the main frame and the hood skin makes it possible to increase the impact deceleration in the middle of the collision against the bending deformation of the hood. There is an effect that the bottom can be substantially reduced by absorbing energy before reaching the bottom.

  According to the invention described in claim 5, since it is possible to suppress the deformation of the closed cross-section structure portion formed between the main frame and the hood skin by the sealer applied between the main frame and the hood skin, There is an effect that impact energy can be absorbed by peeling the sealer before the deformation of the closed cross-section structure portion starts thereafter.

Next, embodiments of the present invention will be described with reference to the drawings.
As shown in FIGS. 1 and 2, the hood 1 is attached to the back surface of the hood skin 2 made of aluminum or aluminum alloy constituting the outer surface of the vehicle body. It is comprised with the food frame 4 arrange | positioned facing inside.

  Here, a tape stiffener 5 (indicated by a chain line in FIG. 1), which is a mass material, is attached to the back surface of the hood skin 2 with an adhesive material on the back surface. The tape stiffener 5 is for increasing the initial impact deceleration level of the hood skin 2, and is a central portion of the hood skin 2, which is an action point of the input impact load, specifically, main frames 7, 7 to be described later. Is provided in a range of about 300 mm in diameter with the intersection 10 as a center. This range is a range in which the surface of the hood skin 2 sinks within 2 to 3 ms from the time of the collision, which is the timing at which the initial impact deceleration occurs (see FIG. 6 described later). The tape stiffener 5 in this embodiment is formed of butyl rubber, and uses a member having a square of about 300 mm and a thickness of about 1.5 mm.

  The hood frame 4 is a member having an opening at a substantially central portion for weight reduction. The hood frame 4 has a pair of main frames 7 and 7 attached so as to straddle the periphery of the opening 6 and ends at the periphery of the opening 6. A pair of subframes 8 (8R) and 8 (8L) is provided. Each of the main frames 7 is a hat-shaped cross-sectional member formed at a position along the main stress axis X direction (shown only in FIG. 1) when an input load is applied to the central portion of the hood skin 2. A closed cross-section structure 9 that is advantageous in strength against bending deformation is formed between the hood skin 2 and a pair of main frames 7 and 7.

  The intersection 10 of the main frame 7 is positioned above the engine, specifically the cylinder head cover 11 as a highly rigid component, as shown in FIGS. Here, the principal stress axis X direction means the direction of the maximum stress among the stresses acting in the direction along the surface of the hood 1 when an input (impact) load is applied to the central portion of the hood 1. ing. In this embodiment, since the maximum stress is detected in the direction slightly inclined in the vehicle width direction in the direction before the vehicle body (FR in FIG. 1) (RR in FIG. 1), the main stress axis X is symmetric in the vehicle width direction. In total, two positions are detected.

  Therefore, the main frames 7 and 7 are arranged in two directions, and the two main frames 7 and 7 are arranged so as to intersect at the intersection 10. In order to determine the principal stress axis X direction, a plurality of load detection rosette gauges are arranged near the center of the hood 1 and an impact load is applied by the impactor W to obtain the principal stress axis direction. Yes.

  Then, a hat-shaped cross-sectional shape that forms a closed cross-sectional structure portion 12 that is advantageous in strength against bending deformation between the hood skin 2 so as to sandwich the intersecting portions 10 of the main frames 7 and 7 from the vehicle width direction. A subframe 8 is provided. The sub frame 8 is formed in a V shape and is provided in a pair in a state where an edge is formed at the periphery of the opening 6 of the hood frame 4. Accordingly, the main frames 7R and 7L and the sub frames 8R and 8L are arranged in the form of a spider web from the central portion of the hood 1, and as shown in FIG. Will be formed.

  As shown in FIGS. 1 and 2, the V-shaped subframe 8 is formed such that the front side portion and the rear side portion are V-shaped, but the two main frames 7R and 7L are formed. Among these, for one main frame 7R whose rear side portion is inclined to the right side of the vehicle body (R direction in FIG. 1), the rear side portion 8LRR of the subframe 8L on the left side of the vehicle body is substantially at a position perpendicularly intersecting this. A front side portion 8RFR of the right subframe 8R on the right side of the vehicle body is provided at a position that intersects vertically, and the other main frame 7L whose rear side portion is inclined to the left side of the vehicle body (L direction in FIG. 1) is perpendicular to this. A rear side portion 8RRR of the right side sub-frame 8R is provided at the intersecting position, and a front side portion 8LFR of the left side sub-frame 8L is provided at a substantially perpendicular position.

That is, each of the main frames 7R and 7L is disposed in the principal stress axis X direction, but another principal stress axis having a force direction opposite to that of the principal stress axis X direction. Therefore, the subframes 8R and 8L are arranged in a direction substantially along the other main axis direction. Here, the bent portion 13 of each of the sub-frames 8R and 8L is connected to the intersecting portion 10 of the main frames 7R and 7L by a substantially U-shaped connecting portion 14.
Therefore, the hood frame 4 is formed with a trapezoidal opening 15 on the front side of the intersection 10 of the main frames 7 and 7 and a triangular opening 16 on the rear side, and the vehicle width direction of each of the subframes 8 and 8 is formed. Triangular openings 17 and 17 are formed on the outer sides, respectively, and triangular openings 18 and 19 are provided on the front and rear sides of the subframes 8 and 8 and on the outer side in the vehicle width direction of the main frames 7 and 7, respectively. Will be formed.

  Then, as shown in FIG. 4, the hood frame 4 described above is superposed on the hood skin 2 to which the tape stiffener 5 is attached, and the periphery of the hood frame 4 is wrapped in the periphery of the hood skin 2. The hood skin 2 is applied with a mastic sealer 21 (shown by hatching in FIG. 1) between the periphery of the hood frame 4 corresponding to the bent portion 20 at the periphery of the hood skin 2 and the back surface of the hood skin 2. The food frame 4 is joined.

Here, the hood skin 2 (and tape) is provided on the peripheral edges of the triangular openings 16 to 19 and the trapezoidal opening 15 of the hood frame 4, that is, on the side edges of the main frames 7 and 7 and the sub frames 8 and 8. A flange portion F (shown only in FIGS. 1 and 3) that is in close contact with the back surface of the stiffener 5) is formed, and a mastic sealer 22 (shown by hatching in FIG. 1) is provided between the flange portion F and the hood skin 2 at a predetermined interval. ) Is applied, and the vicinity of the opening 6 of the hood frame 4 is fixed to the hood skin 2.
That is, the mastic sealer 22 is applied between the flange portion F of the main frame 7 and the sub frame 8 and the hood skin 2 around the portion that is closest to the engine and for which the stroke must be suppressed.

  In this way, the mastic sealer 22 is applied between the flanges at the peripheral edges of the triangular openings 16 to 19 and the trapezoidal opening 15, that is, at least between the flange F of the main frame 7 and the hood skin 2. Thus, the impact energy can be absorbed by peeling the mastic sealer 22 before the closed cross-section structure portion 9 formed between the main frame 7 and the hood skin 2 is crushed and deformed.

Here, as shown on the right side of the vehicle body and on the rear side in FIG. 1, when the back surface of the hood skin 2 is used as a reference, each part of the hood frame 4 has the flange portion F at the lowest position with respect to the engine room side. Next, the top portion 31 of the main frame 7 and the sub frame 8 is set to the highest position through the inclined portion 30, and the connecting portion 14 is set to a height located between the flange portion RF and the top portion 31. Has been. Further, a base portion 32 is formed at a slightly higher position from the peripheral portion so as to surround the inside of the peripheral portion of the hood frame 4, and a high position portion 34 is formed from the base portion 32 through the inclined portion 33 to the periphery of the opening 6. The high position portion 34 is formed at the same height as the top portions 31 of the main frame 7 and the sub frame 8, and is connected to the top portions 31.
1 denotes a hood striker, and a reinforcing reinforcement 36 is attached around the hood striker 35 (not shown in FIG. 2).

  According to the above embodiment, as shown in FIG. 6, when the impactor W collides with the hood skin 2, the hood skin 2 sinks within 2 to 3 ms when the initial impact deceleration occurs. At this time, since the depressed range is strengthened by the tape stiffener 5, the downward displacement can be suppressed. That is, as shown in FIG. 9, the vertical axis indicates the impact deceleration (G) and the horizontal axis indicates the stroke (mm). Increase the energy absorption efficiency.

Next, as shown in FIG. 7, the entire hood 1 is bent downward and further deformed. However, the main frames 7 are arranged in one main stress axis X direction, and the sub frame 8 is also in the other direction. The main frame 7 and the sub-frame 8 are arranged in a direction substantially along the main stress axis direction, and can absorb impact energy between the hood skin 2 reliably in a shearing direction that is advantageous in strength over the length direction. .
Moreover, coupled with the fact that the main frame 7 and the subframe 8 absorb energy effectively against the bending deformation by the closed cross-section structures 9 and 12 formed between the hood skin 2. As shown in FIG. 9, even during the middle of the collision, the energy absorption efficiency can be increased by increasing the impact deceleration and increasing the amount of energy absorption compared to the conventional case, and bringing the waveform of FIG. 9 closer to a rectangular wave.
Of course, a large amount of energy acts in the middle of the collision as described above. However, since the amount of bending deformation is suppressed by the main frame 7 and the subframe 8, the cylinder head cover can be provided even if the clearance with the cylinder head cover 11 of the engine is small. 11 can prevent the hood frame 4 from hitting.

  When the hood 1 is further deformed and the main frame 7 or the sub frame 8 (the main frame 7 in the figure) comes into contact with the cylinder head cover 11, the mastic sealer 22 receives a force in a shearing direction that is advantageous in strength. While being cut, it is stretched and the closed cross-section structures 9 and 12 of the main frame 7 and the subframe 8 are opened and crushed and deformed while causing a shift at the flange F. Therefore, energy is absorbed in a short period of time (by ΔS) in a shorter time than before, with a margin in the late stage of the collision, that is, a large amount of energy is absorbed in the early and middle stages of the collision. As a result, the hood 1 does not bottom the cylinder head cover 11.

  Further, the main frame 7 and the sub frame 8 are arranged in a spider web shape from the central portion of the hood 1, and as shown in FIG. 5, an uneven portion is formed in the vehicle width direction with the intersection 10 as the center. Therefore, even if the impactor W is brought into contact with that portion around the intersecting portion 10, substantially uniform impact energy absorption characteristics can be obtained.

According to the above embodiment, when the hood 1 tries to bend and deform downward due to the impact load acting on the hood skin 2, the hood 1 is against the load in the direction in which the main frame 7 curves the hood 1. 11, and the main frame 7 is arranged in the direction of the main stress axis X of the impact load acting on the hood 1, so that it is advantageous in terms of strength over the mounting length direction of the main frame 7. It is possible to receive a stress with the hood skin 2 in a proper shearing direction, and thus it is possible to reliably absorb impact energy.
In addition, V-shaped subframes 8 and 8 sandwiching the main frame 7 from the vehicle width direction are provided at the intersection 10 of the main frame 7, and between the main frame 7 and the hood skin 2 and between the subframe 8 and the hood. A plurality of closed cross-section structures 9, 12,... Are formed between the skin 2 and the uniform energy regardless of the direction in which the impact load is applied in a portion where the clearance with the high-rigidity part is small. Absorption characteristics can be exhibited.

Further, since it is possible to increase the impact deceleration in the initial stage of the collision, the stroke amount can be reduced by that amount, and the energy can be absorbed until reaching the bottom to substantially reduce the bottom.
Furthermore, since the subframe 8 can be subjected to stress caused by an impact load with the hood skin 2 in a shearing direction that is advantageous in strength over the longitudinal direction, the impact energy can be reliably ensured as in the main frame 7. Can be absorbed.
Even if the hood 1 comes into contact with the cylinder head cover 11 in the late stage of the collision, the impact energy can be absorbed with a short stroke while crushed the closed cross-section structures 9 and 12 from that stage. Can absorb shock loads up to.

  Here, the deformation of the closed cross-section structure portion 9 formed between the main frame 7 and the hood skin 2 by the mastic sealer 22 applied between the flange portion F of the main frame 7 and the subframe 8 and the hood skin 2. Therefore, the impact energy can be absorbed by peeling the mastic sealer 22 before the deformation of the closed cross-section structure portion 9 starts thereafter.

In this way, the impact deceleration at the initial stage of the collision is increased by the tape stiffener 5, the impact deceleration at the middle stage of the collision is increased by the main frame 7 and the sub frame 8 of the hood frame 4, and energy is absorbed with a margin at the end of the collision. The head impact value HIC (Head Injury Criterion) can be reduced by reducing the average impact deceleration, or the impact energy can be absorbed with a small stroke.
That is, as shown in FIG. 9, the initial and medium-term impact deceleration increases to some extent, but the head injury value HIC can be lowered by reducing the stroke and shortening the duration. Further, since the stroke can be reduced, the degree of freedom in modeling can be increased, for example, the height of the hood 1 can be made as low as possible.
In addition, this invention is not restricted to the said embodiment, For example, the material of the tape stiffener 5 can use various resin materials other than butyl rubber. If necessary, a thin metal plate material can be used instead of the tape stiffener 5.

It is a reverse view of the food | hood of embodiment of this invention. It is a disassembled perspective view of the food | hood of embodiment of this invention. It is sectional drawing which follows the AA line of FIG. It is sectional drawing which follows the BB line of FIG. It is sectional drawing which follows the CC line of FIG. It is a figure explaining a collision situation. It is a figure explaining a collision situation. It is a figure explaining a collision situation. It is a graph which shows the relationship between an impact deceleration and a stroke.

Explanation of symbols

1 Food 2 Food skin 5 Tape stiffener (mass material)
7 Main frame 8 Sub frame 9 Closed cross-section structure 10 Crossing 11 Cylinder head cover (high rigidity part)
22 mastic sealer (sealer)
X principal stress axis

Claims (5)

  A pair of main frames provided on the back side of the hood skin are arranged so as to intersect each other at a position above the high-rigidity part, and this main frame is formed in the main stress axis direction with respect to the input load. A hood structure for an automobile, wherein a pair of V-shaped subframes are provided so as to sandwich the portion.   2. The automobile hood structure according to claim 1, wherein a mass material is provided on a back side of the hood skin at a position centering on an intersecting portion of the main frame.   3. A part of the V-shaped sub-frame is formed in another main stress axis direction corresponding to the main frame formed in the main stress axis direction. Automobile hood structure.   4. The automobile hood structure according to claim 1, wherein at least the hood skin and the main frame form a closed cross-section structure portion, and the closed cross-section structure portion is crushed and deformable. 5. .   The automobile hood structure according to any one of claims 1 to 4, wherein a sealer is applied between the main frame and a hood skin with a portion closest to the high-rigidity part as a center.

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