JP2010188966A - Vehicle body front part structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle body front part structure which sufficiently absorbs an impact of contact (collision) with an obstacle. <P>SOLUTION: In the vehicle body front part structure 11, with a load applied by contacting the obstacle M, a front bumper 16 (bumper face 37) generates a maximum reaction force Fmb of the front bumper 16 at an intermediate position (S1), and generates a fixed front bumper remaining reaction force Fb after descending. A front grille 15 and a hood 21 raise a rising reaction force at a fixed inclination in succession to a dropping reaction force after the intermediate position (S1), generate a maximum reaction force Fmg of the front grille 15 and a maximum reaction force Fmf of the hood 21 at the time of achieving desired deformation amounts (S4, S5), and retain them constant for a period of remaining deformation amounts. In this manner, a total maximum reaction force Fm including the maximum reaction force Fmg of the front grille 15, the maximum reaction force Fmf of the hood 21, and the remaining reaction force Fb of the front bumper 16 remains constant and does not exceed a desired specified value Fu. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention includes a front grille and a front bumper positioned in front of a vehicle, a radiator disposed behind them, and a hood that covers an apparatus such as a radiator above, and a vehicle body front structure corresponding to an obstacle. It is about.

  There is a vehicle body front structure in which an energy absorbing member for protecting a pedestrian is provided on the front bumper in front of the vehicle, and a pedestrian is provided below the energy absorbing member with a protruding portion protruding forward from the energy absorbing member. When the pedestrian falls to the hood (hood) side, the impact energy of the pedestrian's knee is projected forward of the vehicle from the line connecting the tip of the hood (hood) and the tip of the protrusion. There exists what absorbs with an energy absorption member (for example, refer to patent documents 1 (Drawing 1, Drawing 2)).

However, although the prior art (Patent Document 1) absorbs the impact energy of a pedestrian by the energy absorbing member, there is a problem that the energy absorbing member cannot be adopted for a vehicle that cannot be largely moved forward from the front end of the hood.
Similarly, it is not suitable for a vehicle that cannot be protruded forward from the vehicle width direction member (bumper beam) of the front bumper. In such a vehicle, for example, a vehicle with a high vehicle height such as an SUV vehicle, in order to prevent interference between the front bumper and the steep slope of the rough terrain, the front bumper needs to be high and close to the front wheel. There is a problem that it is difficult to install.
Also, in a vehicle with a high vehicle height such as an SUV vehicle, the length in the vehicle front-rear direction from the front bumper tip to the front hood tip or front grille is short in the side view of the vehicle. There is a problem that a sufficient energy absorbing member cannot be stored.

Japanese Patent No. 3740901

  The present invention provides a vehicle body front structure that sufficiently absorbs an impact when contacting (collision) with an obstacle even in a vehicle in which the distance from the front bumper to the front grille is short and the shock absorbing member cannot be stored in the front bumper. Is an issue.

  In order to solve the above-mentioned problem, the invention according to claim 1 is a vehicle body front part structure including a front bumper and a front grill located in front of the vehicle, and a hood extending from above the front grill to the vehicle rear. The front bumper generates a maximum front bumper reaction force at the middle position in the process of retreating to the lower part of the front end of the hood by the load when the front of the vehicle contacts an obstacle. After generating a force, a constant front bumper residual reaction force is generated, and the front grille and the hood incline the rising reaction force continuously with the descending reaction force in the process of retreating with the front bumper after the intermediate position. When the desired retraction amount is reached, the front grille maximum reaction force and the hood maximum reaction force are generated and kept constant for the remaining retraction amount. Lil maximum reaction force and the hood maximum reactive force and the front bumper residual reaction force and overall maximum reaction force which is the sum of the constant, and characterized in that it does not exceed the desired predetermined value.

In the invention according to claim 1, the front bumper generates a front bumper maximum reaction force at an intermediate position in the process of retreating to the lower side of the front end of the hood by the load when it comes into contact with an obstacle, and further descends as it retreats. Then, a certain front bumper residual reaction force is generated, and the front grille and the hood are continuously lifted and counteracted in the process of retreating with the front bumper after the intermediate position. When the force is raised at a constant slope and the desired amount of reverse movement is reached, the maximum reaction force of the front grille and the maximum reaction force of the hood are generated and kept constant for the remaining amount of reverse movement. The total maximum reaction force, which is the sum of the hood maximum reaction force and the front bumper residual reaction force, is constant and does not exceed the desired specified value. Therefore, the reaction force does not increase rapidly and the maximum reaction force is reduced. You There is the advantage that it is possible.
That is, even when the distance from the front bumper to the front grill (average of the front grille) is short and the impact absorbing member cannot be stored in the front bumper, the impact when contacting (collising) the obstacle can be sufficiently absorbed.

It is a figure explaining the outline | summary of the vehicle body front part structure which concerns on the Example of this invention. It is a perspective view of the body front part structure concerning an example. It is sectional drawing of the vehicle body front part structure which concerns on an Example. It is a perspective view of the protection plate contained in the front bumper of a vehicle body front part structure. It is sectional drawing of the protection plate of a vehicle body front part structure. It is a perspective view of the grill bracket provided in the front grill of the body front part structure. It is a rear view of the grill bracket of a vehicle body front part structure. It is the figure which looked at the food | hood of the vehicle body front part structure from the downward direction. It is a perspective view of a front bulkhead and a radiator / capacitor support mechanism arranged on the back side of the front grille of the vehicle body front structure. FIG. 10 is a detailed view of part 10 of FIG. 9. It is a figure explaining the mechanism which reduces the reaction force of the protection plate provided in the front bumper of the vehicle body front part structure. It is a figure explaining the mechanism which reduces the reaction force of the front grille of a vehicle body front part structure. It is a figure explaining the mechanism which reduces the reaction force of the bumper face of a vehicle body front part structure, a radiator capacitor | condenser support mechanism, and a hood. It is a figure explaining in detail the mechanism which reduces the reaction force of the radiator capacitor | condenser support mechanism of a vehicle body front part structure. It is a figure explaining the mechanism which reduces the total reaction force of a vehicle body front part structure.

  Hereinafter, embodiments of the present invention will be described in detail with reference to examples.

  As shown in FIGS. 1 and 2, the vehicle body front portion structure 11 according to the embodiment includes a front grill 15 and a front bumper 16 that are located on the front surface 13 of the vehicle 12, a radiator 17 that is disposed behind them, and a radiator 17. And a hood 21 that covers a device such as the above. This will be specifically described below.

  As shown in FIGS. 1 to 3, the vehicle body front structure 11 is employed in the front portion 23 of the vehicle 12, and the distance Lf from the front bumper 16 to the front grill 15 (average of the front grill 15) is short. The front bumper 16 does not contain an impact absorbing member, but protects the pedestrian when it comes into contact with an obstacle M, for example, a pedestrian.

  The vehicle body front structure 11 includes a hood 21 that covers devices such as the engine 26 in the front body 25 of the vehicle 12, a bumper beam 31 spanned between the front end portions 28 of the left and right front side frames 27, and a front bulk A head 33, a grill bracket 35 provided on the back of the front grill 15 so as to suppress the deflection of the front grill 15, a bumper face 37 provided in front of the vehicle body of the bumper beam 31, and the front of the bumper beam 31 and the front bulkhead 33. And a protection plate 41 provided on the lower cross member 38.

  The vehicle 12 is an SUV vehicle having a high vehicle height. The vehicle compartment 43, an engine room 44 connected in front of the vehicle compartment 43, a front side upper member 45 continuous above the front side frame 27, a hood lock device 46, Left and right front wheels 51 provided below the left and right front fenders 47.

  The bumper beam 31 extends in the vehicle width direction in front of the vehicle body of the left and right front wheels 51, is formed in a U-shaped cross section shown in FIG. 5, the opening is disposed toward the rear of the vehicle, and supports the bumper face 37.

The bumper face 37 is made of resin and is formed in an L-shaped cross section as shown in FIG. 3. A space is formed by separating the bumper face 31 from the bumper beam 31 to the front of the vehicle by a predetermined distance, and the top portion 37 a is disposed substantially horizontally. The front portion 37b is arranged substantially vertically and is attached to the bumper beam 31 with a bracket (not shown).
The characteristics of the resin used for the bumper face 37 are arbitrary.
The thickness (thickness) of the bumper face 37 is arbitrary.

  As shown in FIGS. 2 to 4, the front bulkhead 33 includes left and right bulkhead side frames 52 provided on the left and right front side frames 27, and a front lower cross at the lower ends of the left and right bulkhead side frames 52. A member 38 is bridged. The protective plate 41 is supported below the bumper beam 31.

  The protection plate 41 is attached to the bumper beam 31 and the front lower cross member 38, and is a plate bent in a substantially V shape so as to bulge from the bumper beam 31 and the front lower cross member 38 toward the front of the vehicle body in a side view of the vehicle. (Plate-shaped) member.

  The protective plate 41 includes an upper end mounting portion 54 attached to the bumper beam 31 in FIGS. 3 to 5, an upper surface portion 55 projecting from the upper end mounting portion 54 toward the front of the vehicle body, and downward from the upper surface portion 55. A front surface portion 56 bent toward the front, a lower surface portion 57 bent from the front surface portion 56 toward the rear of the vehicle body, and a lower end mounting portion 58 provided at the rear end of the lower surface portion 57 and attached to the front lower cross member 38. And.

The upper end mounting portion 54 is fixed (attached) to the beam front wall of the bumper beam 31 by welding.
The upper surface portion 55 is bent at the lower end of the upper end mounting portion 54 so as to protrude downwardly toward the front of the vehicle body.

  The front surface portion 56 is bent at the front end 55a of the upper surface portion 55, and is bent downward and toward the rear of the vehicle body.

The lower surface portion 57 is bent toward the rear of the vehicle body by being bent at the lower end of the front surface portion 56.
The lower surface portion 57 is provided with a bent portion 61 that protrudes downward substantially in the center. Therefore, the lower front part 62 on the front side of the bent part 61 and the lower rear part 63 on the rear side of the bent part 61 are bent downward in a substantially square shape.

Further, the lower surface portion 57 is disposed above an approach inclination line 67 (see also FIG. 1) connecting the ground contact point 65 (see FIG. 1) of the left and right front wheels 51 to the front end lower portion 66 of the front bumper 16.
By arranging the lower surface portion 57 above the approach inclination line 67, the approach angle θ can be suitably secured.
As shown in FIG. 1, the approach angle θ is an inclination angle of the approach inclination line 67 with respect to the horizontal line.

  Further, the lower surface portion 57 has a bent portion 61 that is bent downward when the impact load acts on the front surface portion 56 from the front of the vehicle body as indicated by an arrow a1 (see FIG. 11), so that the lower surface front portion 62 is moved downward in the vehicle body. The lower surface rear portion 63 is formed so as to protrude substantially upward and to be substantially horizontal.

  As shown in FIG. 5, the lower surface portion 57 includes a plurality of lower surface front beads (rigid portions) 71 on the lower surface front portion 62, and a plurality of lower surface rear beads (rigid portions) 72 on the lower surface rear portion 63. Yes.

  The lower front bead 71 has a substantially rectangular shape and bulges downward, and is formed above the bent portion 61 while avoiding the bent portion 61. By providing a plurality of lower surface front bead 71 on lower surface front portion 62, the rigidity of lower surface front portion 62 can be increased.

  The lower surface rear bead 72 bulges downward in a substantially rectangular shape, is formed from the vicinity of the bent portion 61 to the vicinity of the rear end of the lower surface portion 57, and avoids the bent portion 61 and is below the bent portion 61. Is formed. By providing a plurality of lower surface rear beads 72 on the lower surface rear portion 63, the rigidity of the lower surface rear portion 63 can be increased.

The upper end mounting portion 54 includes a plurality of upper beads (rigid portions) 74.
The upper bead 74 bulges toward the rear of the vehicle body, and is formed from the upper end of the upper surface portion 55 to the upper end of the upper end mounting portion 54 through the lower end of the upper end mounting portion 54.

The lower end mounting portion 58 is provided with a plurality of lower beads (rigid portions) 75.
The lower bead 75 bulges toward the front of the vehicle body and is formed from the vicinity of the rear end of the lower surface portion 57 to the lower end of the lower end mounting portion 58.

  The upper end attaching portion 54 and the lower end attaching portion 58 are provided with a plurality of upper beads 74 on the upper end attaching portion 54 and a plurality of lower beads 75 on the lower end attaching portion 58. The strength is set higher than that of the portion excluding the front portion 62 and the lower surface rear portion 63.

Next, the relationship between the front grill 15, the hood 21, and the radiator 17 will be described.
As shown in FIGS. 3, 6, and 9, the hood lock device 46 includes a hood lock mechanism 78 disposed on the front bulkhead 33, a striker 81 that is engaged (locked) and locked to the hood lock mechanism 78, and And handling is the same as existing ones.

  The engine room 44 includes a front bulkhead 33, left and right bulkhead side frames 52 hanging from the front bulkhead 33, and a bulkhead side frame 52, which form the skeleton of the front end shown in FIGS. 2, 3, and 9. The front lower cross member 38 is supported at the lower part of the vehicle body, and is included in the vehicle body front structure 11.

  As shown in FIGS. 2, 3, and 9, the front bulkhead 33 is connected to the front side upper member 45, and a bulkhead corner portion 85 in which a tip end portion 84 is disposed near the middle of the height of the engine room 44. And a bulkhead side portion 86 that is connected to the tip end portion 84 of the bulkhead corner portion 85 and extends upward, and a bulkhead upper portion that is attached to a retreat portion 87 in which the upper end of the bulkhead side portion 86 extends rearward of the vehicle 12. And a hood lock mechanism 78 that locks the hood 21 to the front body 25 on a rear surface 92 of the bulkhead upper portion 91 that faces the rear of the vehicle 12.

  The front grill 15 includes an upper grill 95, a lower grill 96, and a grill bracket 35 shown in FIGS. 1, 3, and 7, and the grill bracket 35 is disposed on the back surface 97 of the front grill 15, A vertical stay 101 extending in the vertical direction is provided on a support stay 98 supported by the bulkhead side portion 86 of the bulkhead 33.

  The vertical stay 101 is a pair of left and right, and changes the strength of the front grille 15 by setting the distance Ws between the left and right. That is, when the distance Ws between the left and right is increased, the amount of deformation until the front grill 15 comes into contact with the radiator 17 and the condenser 102 increases, and as a result, the strength of the front grill 15 decreases.

The vertical stay 101 is connected by a connecting stay 104 that connects the left and right.
The support stay 98 is connected to the front bulkhead 33 and extends to the vicinity of the front grille 15, the lateral stay part 106 connected to the vertical stay 101 connected to the vicinity of the front grille 15 of the buckling stay part 105, and Consists of.

The grill bracket 35 is substantially symmetrical on the left and right with respect to the center line C (FIG. 7).
Further, the lower stay 107 of the buckling stay portion 105 and the lower lateral stay 108 of the lateral stay portion 106 are connected to the lower portion of the bulkhead side portion 86 and connected to the vertical stay 101.

  The vertical stay 101 is connected to the upper edge shown in FIG. 7, and a rear extension 111 is formed extending rearward of the vehicle 12, and the front end of the rear extension 111 faces downward below the upper grill 95. A lower end (front extension portion 112) is formed which is fixed to the lower surface and extends to the front of the vehicle 12 along the lower edge, and the tip of the lower end (front extension portion 112) is connected to the lower surface of the lower grill 96 and the bumper face upper surface. It is fixed to the part 114.

  As shown in FIGS. 2, 3, and 8, the hood 21 has a cover front portion 117 arranged at least above the engine room front portion 116 of the engine room 44 of the hood 21 and the cover front portion 117. The strength is lower than that of the cover rear portion 118.

  The hood 21 also includes a steel plate outer panel 121, a resin front inner frame 122 provided in the range of the cover front portion 117 in the back of the outer panel 121, and a steel plate rear inner provided on the remaining back. A frame 123 and a hood reinforcing stay 125 coupled to the front portion of the rear inner frame 123 by welding and integrally coupled to the outer panel 121 with an adhesive, and a front body near the front end of the rear inner frame 123. A striker 81 is provided that is locked to a hood lock mechanism 78 attached to the bulkhead upper portion 91 on the 25th side.

The outer panel 121 has an existing shape (design) and secures the same manufacturing method as the conventional one.
The outer panel 121 is attached with the inner frame 127 including the rear inner frame 123 and the front inner frame 122 already described.

The cover front portion 117 is a range using the front inner frame 122.
The length of the cover front portion 117 in the longitudinal direction of the vehicle 12 is Lf on average.
The characteristics of the resin used for the front inner frame 122 are arbitrary.

  The hood reinforcement stay 125 connects the front leg 131 to the front inner frame 122 and the rear inner frame 123, and the rear leg 132 to the striker 81 via the rear inner frame 123.

Next, the radiator / capacitor support mechanism 135 that supports the radiator 17 and the capacitor 102 will be described with reference to FIGS.
The radiator / capacitor support mechanism 135 tilts the radiator 17 and the capacitor 102 toward the rear of the vehicle body (in the direction of the arrow a2 in FIGS. 13 and 14) by an impact input to the radiator 17 and the capacitor 102 from the front of the vehicle body.

  The radiator / capacitor support mechanism 135 is also mounted on the bracket mounting portion 137 and a bracket mounting portion 137 that is pivotably stacked on the inner surface 136 of the bulkhead side portion 86 facing the radiator 17 (in the direction of arrow a5). And the rotation restricting claw 138 for restricting the rotation of the bracket attaching portion 137, the extending fitting portion 141 extending continuously from the bracket attaching portion 137, and the extending fitting portion 141, and the projection 142 of the radiator 17 and A fitting hole 144 that engages with the protrusion 143 of the capacitor 102 and rotates against the rotation restricting claw 138 to release the fitting of the protrusions 142 and 143 when the vehicle front face 13 receives an impact; It has.

Specifically, the radiator / capacitor support mechanism 135 includes a first bracket 146 used for the radiator 17 and a second bracket 147 used for the capacitor 102, each of which includes a bracket mounting portion 137, a rotation restricting claw 138, and an extension. A fitting portion 141 and a fitting hole 144 are provided.
The rotation restricting claw 138 is fitted in a hole 148 formed in the bulkhead side portion 86.

The bracket mounting portion 137 has a fulcrum hole 151 formed in the center, and is attached by a bolt (not shown) that passes through the fulcrum hole 151 and a hole of the bulkhead side portion 86 (similar to the fulcrum hole 151).
The protrusions 142 and 143 are fitted in the fitting hole 144 via the buffer member 152.

Next, the operation of the protective plate 41 of the vehicle body front structure 11 according to the embodiment of the present invention will be described with reference to FIG.
A case where an impact load is applied to the front surface portion 56 of the protective plate 41 from the front of the vehicle body will be described with reference to FIG. In FIG. 11, the deformation of the protective plate 41 will be described with the bumper face 37 removed for easy understanding.

When the protective plate 41 collides with the obstacle M, the vehicle body front structure 11 contacts the front end 55a of the upper surface portion 55. When the obstacle M hits the front end 55a of the upper surface portion 55, an impact load acts on the front end 55a of the upper surface portion 55 as shown by an arrow a1, so that the bent portion 61 is bent downward into a dogleg shape. Then, when the bent portion 61 is bent downward, the lower surface front portion 62 protrudes (projects) downward in the vehicle body.
As described above, the front surface portion 56 can receive the obstacle M by deforming the lower surface front portion 62 toward the lower side of the vehicle body.
In this state, the lower surface front portion 62 is further deformed toward the lower side of the vehicle body. Thereby, the protective plate 41 can be crushed by L dimension toward the rear of the vehicle body, and the impact load acting on the obstacle M can be absorbed.
That is, the reaction force of the impact on the pedestrian M can be reduced.

Further, by deforming the lower surface front portion 62 toward the lower side of the vehicle body, the obstacle M can be received in a wide area of the lower surface front portion 62 and the front surface portion 56 deformed toward the lower side of the vehicle body.
Thereby, the surface pressure of the impact load which acts on the obstacle M can be suppressed small, and the obstacle M can be favorably protected.

  In addition, the lower surface front portion 62 projects H dimension downward toward the vehicle body, thereby preventing the obstacle M from being caught under the vehicle body (that is, the vehicle body front structure 11) by the projected lower surface front portion 62. be able to.

Here, when the obstacle M collides with the front surface portion 56 (specifically, the front end 55a of the upper surface portion 55), the protection plate 41 keeps the lower surface rear portion 63 substantially horizontal.
A buckling load is applied to the lower surface rear portion 63 by keeping the lower surface rear portion 63 substantially horizontal. Therefore, compared with the case where a bending load acts on the lower surface rear part 63, a large load can be supported by the lower surface rear part 63.

Accordingly, the lower surface rear portion 63 can be prevented from being deformed by an impact load, and the lower surface front portion 62 protruding downward from the vehicle body can be held by the lower surface rear portion 63.
As a result, the obstacle M can be prevented from being caught in the lower part of the vehicle body by the protruding lower front part 62.

Further, by providing the lower surface front portion 62 and the lower surface rear portion 63 of the lower surface portion 57 with a plurality of lower surface front beads 71 and a plurality of lower surface rear beads 72, respectively, when the impact load acts, It is possible to prevent the rear portion 63 from buckling.
On the other hand, the bending portion 61 of the lower surface portion 57 is not provided with a reinforcing bead so that it can be bent more easily than the lower surface front portion 62 and the lower surface rear portion 63.

In addition, by providing a plurality of upper beads 74 on the upper end attaching portion 54 and providing a plurality of lower beads 75 on the lower end attaching portion 58, the upper end attaching portion 54 and the lower end attaching portion 58 are set to have high strength.
Therefore, the upper end mounting portion 54 and the lower end mounting portion 58 can be reliably supported by the bumper beam 31 and the front lower cross member 38, and stress can be concentrated on the bent portion 61 of the lower surface portion 57 of the protective plate 41. it can.

Next, the operation of the front grill 15 (grill bracket 35) of the vehicle body structure 11 according to the embodiment of the present invention will be described with reference to FIG.
The vehicle body structure 11 holds the front grill 15 while the grill bracket 35 is deformed when the vehicle 12 and an obstacle (for example, a pedestrian) M (FIG. 1) are in contact with each other as indicated by an arrow a6. Suppresses the bending.

  Specifically, when the center of the front surface 13 of the vehicle 12 contacts (collises) an obstacle (for example, a pedestrian), the front grill 15 (upper grill 95, lower grill 96) is deformed rearward of the vehicle 12, and the grill bracket 35 is pressed. Since the grille bracket 35 supports the front grille 15 being deformed by the vertical stays 101 that are separated from the center of the front grille 15 by a distance W1 to the left and right, it absorbs shock while deforming the center of the front grille 15. Can be secured, and the bending of the front grille 15 can be suppressed.

  When the center of the front surface 13 of the vehicle 12 contacts (collises) an obstacle (for example, a pedestrian), the vertical stay 101 transmits and distributes the load to the connecting stay 104, so that the vehicle stays in the vehicle width direction (the direction of the arrow a7). The strength against force can be improved to increase the efficiency of shock absorption.

In the support stay 98 (see FIG. 7), when the center of the front surface 13 of the vehicle 12 contacts (collises) an obstacle (for example, a pedestrian), a compressive load is applied to the buckling stay portion 105, and the buckling stay portion 105 is seated. Therefore, the impact can be absorbed by the buckling of the buckling stay portion 105.
Thus, the reaction force of the impact on the pedestrian M can be reduced.

  Next, operations of the bumper face 37, the hood 21, and the radiator / capacitor support mechanism 135 of the vehicle body front structure 11 according to the embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 13, the vehicle body front structure 11 is disposed substantially horizontally so that the bumper face 37 is deformed when the vehicle 12 and an obstacle (for example, a pedestrian) M (FIG. 1) contact each other. The reaction force of the impact on the pedestrian M can be reduced by the deformation of the top part 37a.

  As shown in FIG. 13, when the vehicle 12 and an obstacle (for example, a pedestrian) M (FIG. 1) are in contact with each other, the front body structure 11 of the vehicle body is deformed by the cover front portion 117 of the hood 21 so that the pedestrian The reaction force of the impact on M can be reduced.

Specifically, as the bumper face 37 is retracted rearward due to the deformation of the bumper face 37, the cover front portion 117 of the hood 21 starts to be deformed and retracted. The cover front portion 117 is a portion where the strength is set to be low by the resin front inner frame 122 with respect to the entire hood 21, so that the load at the start of deformation can be made smaller than the hood 21 where the strength is not set low. The deformation range (stroke) can be increased (for example, up to the distance S). Therefore, the impact applied to the pedestrian M can be reduced.
That is, the reaction force of the impact on the pedestrian M can be reduced.

  At that time, the front bulkhead 33 (bulkhead side portion 86, bulkhead upper portion 91) can retract the hood lock mechanism 78 rearward of the vehicle 12, and the cover front portion 117 of the hood 21 in the vehicle 12 front-rear direction. A large length Lf (FIG. 8) can be secured. Therefore, the impact absorption stroke S of the vehicle front 13 can be further increased.

In the vehicle body front part structure 11, the radiator / capacitor support mechanism 135 shown in FIG. 14 rotates as indicated by an arrow a6 when an impact from an obstacle (pedestrian) M is input to the front surface 13 of the vehicle. 17 and the capacitor 102 can be tilted to the rear of the vehicle 12 as indicated by an arrow a2, and the structure of the vehicle body front structure 11 that tilts the radiator 17 and the capacitor 102 to the rear of the vehicle 12 is simplified.
When the vehicle front 13 is not impacted by an obstacle (pedestrian) M, the radiator / capacitor support mechanism 135 causes the radiator / capacitor support mechanism 135 due to vibration during normal travel by the rotation restricting pawl 138 (FIG. 10). Can be prevented from rotating.

  Next, a mechanism for reducing the total reaction force of the vehicle body front structure 11 according to the embodiment of the present invention will be described with reference to FIGS. 15A is a conceptual diagram based on FIG. 3, FIG. 15B is a graph showing the relationship between the reaction force of the bumper face 37 and the deformation amount of the bumper face 37, and FIG. 15C is the reaction force of the front grill 15 and the front grill 15. (D) is a graph showing the relationship between the reaction force of the hood 21 and the deformation amount of the hood 21, and (e) is a graph showing the relationship between the total reaction force of the vehicle body front structure 11 and the vehicle body front structure 11. It is a graph which shows the relationship of deformation amount. In these graphs, the horizontal axis represents the amount of deformation when the center in the vehicle width direction contacts (impacts) the obstacle M, and the vertical axis represents the reaction force.

  (B): As shown in FIG. 13, when the bumper face 37 contacts (collises) the obstacle M and a load is input and is deformed by the deformation amount S1, the reaction force reaches the maximum reaction force Fmb. When the deformation continues and the deformation is deformed by the deformation amount S3, the reaction force drops to the front bumper residual reaction force Fb, and the front bumper residual reaction force Fb is kept constant.

The deformation amount S1 is a substantially intermediate position up to the front grille 15 (distance Lf), and the deformation amount S3 is the position of the front grille 15.
The bumper face 37 is deformed together with the protective plate 41 (see FIG. 11).
After the bumper face 37 abuts on the bumper beam 31 (nearly before the deformation amount S2), the top portion 37a generates a reaction force.

  (C): As shown in FIG. 13, the front grille 15 begins to deform when the front end of the front grille 15 contacts (collises) the obstacle M (position of the deformation amount S2), and the reaction force is substantially constant. When it rises at the rising speed and the deformation amount becomes S4, the reaction force reaches the maximum reaction force Fmg, and thereafter the reaction force Fmg is kept constant even if the deformation continues.

  When the deformation amount reaches S4, the front grille 15 comes into contact with the grill bracket 35 (see FIG. 12) and moves backward (deforms) together with the grill bracket 35. When the vehicle further moves backward, the radiator / capacitor support mechanism 135 in FIG. 14 moves backward (deforms) together with the radiator 17 and the capacitor 102 to the rear of the vehicle.

  (D): As shown in FIG. 13, the hood 21 starts to deform when the tip of the hood 21 contacts (collises) with the obstacle M (position of the deformation amount S3), and the reaction force has a substantially constant rising speed. When the deformation amount reaches S5, the reaction force reaches the maximum reaction force Fmf, and thereafter the reaction force Fmf is kept constant even if the deformation continues.

(E): The vehicle body front part structure 11 generates a reaction force that is the sum of the reaction forces already described in (b), (c), and (d) in the process up to the deformation amount S5, and the deformation amount S5. Generates a maximum reaction force Fm, and keeps the maximum reaction force Fm constant in the process of deformation after the deformation amount S5.
The reaction force Fm is less than the desired upper limit specified value Fu.

  As a result, the vehicle body front structure 11 has a short distance Lf from the front bumper 16 to the front grille 15 (average of the front grille 15), and even in a vehicle in which the shock absorbing member cannot be stored in the front bumper 16, There is an advantage that the reaction force does not rise rapidly.

  As described above, the vehicle body front structure 11 according to the embodiment includes the front bumper 16 and the front grille 15 that are positioned on the front surface 13 of the vehicle 12, and the hood 21 that extends from above the front grille 15 to the rear of the vehicle 12, The front bumper 16 (specifically, mainly including the protective plate 41 by the bumper face 37) is retracted to the lower side of the front end of the hood 21 by the load when the front surface 13 of the vehicle 12 contacts the obstacle M (deformation amount S3). The maximum reaction force Fmb of the front bumper 16 (specifically, the bumper face 37) is generated at an intermediate position in the process (position of the deformation amount S1), and further descends as the vehicle moves backward. After generating the reaction force (reaction force between the deformation amount S1 and the deformation amount S3), a constant front bumper residual reaction force Fb is generated, and the front grill 15 and the hood 21 are After the intermediate position (the position of the deformation amount S1), in the process of retreating together with the front bumper 16, specifically the bumper face 37, it continues to the descent reaction force (reaction force between the deformation amount S1 and the deformation amount S3). Increase reaction force (deformation amount S2 to S4 of (c), deformation amount S3 to S5 of (d)) with a constant inclination (between deformation amount S2 and deformation amount S3), and a desired retraction amount When the deformation amount (deformation amount S4 of (c), deformation amount S5 of (d)) is reached, the front grill 15 maximum reaction force Fmg and the hood 21 maximum reaction force Fmf are generated, and the remaining retraction The amount of deformation (the deformation amount S4 after (c) and the deformation amount S5 after (d)) is kept constant, and the front grill 15 maximum reaction force Fmg, the hood 21 maximum reaction force Fmf, and the front bumper Total total of 16 residual reaction forces Fb Reaction force Fm is constant, so and do not exceed the desired predetermined value Fu, it is possible to reduce the reaction force of the vehicle body front structure 11. Therefore, even when the distance Lf from the front bumper 16 to the front grille 15 (the average of the front grille 15) is short and the shock absorbing member cannot be stored in the front bumper 16, the impact when contacting (collising) the obstacle M is sufficient. Can be absorbed.

  The vehicle body front structure of the present invention is suitable for a vehicle in which the distance from the front bumper to the front grille is short and the shock absorbing member cannot be stored in the front bumper.

  DESCRIPTION OF SYMBOLS 11 ... Vehicle body front structure, 12 ... Vehicle, 13 ... Front of vehicle, 15 ... Front grille, 16 ... Front bumper, 21 ... Hood, 37 ... Bumper face, 41 ... Protection plate, Fb ... Front bumper residual reaction force, Fm ... total maximum reaction force, Fmb ... maximum reaction force, Fmf ... hood maximum reaction force, Fmg ... front grille maximum reaction force, Fu ... specified value, M ... obstacle, S1 ... intermediate position.

Claims (1)

In a vehicle body front structure comprising a front bumper and a front grill located in front of the vehicle, and a hood extending from above the front grill to the rear of the vehicle,
The front bumper generates a front bumper maximum reaction force at an intermediate position in the process of retracting to the lower end of the front end of the hood by the load when the front of the vehicle contacts an obstacle, and descends as the vehicle further retracts. After generating a certain descent reaction force, a certain front bumper residual reaction force is generated, and the front grille and the hood continue to the descent reaction force in the process of retreating with the front bumper after the intermediate position. The rising reaction force is raised at a constant slope, and when the desired amount of retraction is reached, the front grill maximum reaction force and the hood maximum reaction force are generated and kept constant for the remaining retraction amount,
The vehicle body front structure, characterized in that a total maximum reaction force obtained by adding the front grill maximum reaction force, the hood maximum reaction force, and the front bumper residual reaction force is constant and does not exceed a desired specified value.

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