Vehicle front body structure

A vehicle front body structure includes: a vehicle body structural member disposed below a front end of a hood and extends substantially along the vehicle width direction; and an energy absorbing member that protrudes toward a vehicle front side from the vehicle body structural member, extends substantially along the vehicle width direction, and deforms so as to absorb energy upon a collision. The energy absorbing member is secured to the vehicle body structural member at opposite ends of the energy absorbing member in the vehicle width direction. A clearance is defined between a central part of the energy absorbing member in the vehicle width direction and the vehicle body structural member.

CROSS REFERENCES TO RELATED APPLICATIONS

The present application claims priority from Japanese Patent Application No. 2013-062102 filed on Mar. 25, 2013, the entire contents of which are hereby incorporated by reference.

BACKGROUND

1. Technical Field

The present invention relates to a vehicle front body structure and more particularly relates to a vehicle front body structure that can enhance protection for the femoral region of a pedestrian and can reduce damage to a vehicle body at a light collision.

2. Related Art

A vehicle front body structure for a vehicle such as an automobile is required to have enhanced protection for a pedestrian so as to reduce damage to the pedestrian at a collision between the vehicle and the pedestrian.

When a passenger car having a typical vehicle height collides with a pedestrian, a part near a front end of a hood often collides with the femoral region of the pedestrian. Accordingly, in order to suppress damage to the femoral region, the vehicle is required to have a structure that can effectively absorb energy at the hood front end.

As related art concerning a vehicle front body structure for protection of the femoral region of a pedestrian, for example, Japanese Unexamined Patent Application Publication (JPA) No. 2006-264495 discloses a structure in which a bracket protrudes forward from a radiator upper support disposed below a hood front end and absorbs energy upon a collision between a pedestrian and the vehicle, so that damage to the pedestrian can be reduced.

Also, JP-A No. 2007-1358 discloses a structure including a pedestrian protection member made of a sheet metal panel and disposed in front of a bumper beam.

It is possible to enhance protection for a pedestrian with an energy absorbing member attached to a support member on an upper end of a radiator, as disclosed in JPA No. 2006-264495.

However, in the case where a vehicle lightly collides against, for example, another vehicle, or a wall, and the energy absorbing member receives a larger load than a load generated at a collision with a pedestrian, the energy absorbing member may press a vehicle body structural member and result in damage to the vehicle body structural member. Accordingly man-hours for repair, repair cost, and the like may increase.

SUMMARY OF THE INVENTION

The present invention has been designed in consideration of the circumstances described above, and an object of the invention is to provide a vehicle front body structure that can enhance protection for the femoral region of a pedestrian and reduce damage to a vehicle body at a light collision.

An aspect of the present invention provides a vehicle front body structure including: a vehicle body structural member disposed below a front end of a hood and extends substantially along the vehicle width direction; and an energy absorbing member protruding toward a vehicle front side from the vehicle body structural member, and extending substantially along the vehicle width direction, the energy absorbing member being configured to deform so as to absorb energy upon a collision. The energy absorbing member is secured to the vehicle body structural member at opposite ends of the energy absorbing member in the vehicle width direction. A clearance is defined between a central part of the energy absorbing member in the vehicle width direction and the vehicle body structural member.

A weak portion having a low fracture and deformation strength against a compressive load in the vehicle longitudinal direction may be provided in the vicinity of a coupler of the energy absorbing member and the vehicle body structural member.

A rear edge of the energy absorbing member at a central part in the vehicle width direction may be formed in an arch-like shape that is convex toward a vehicle front side.

The vehicle body structural member, to which the energy absorbing member is attached, may be a substantially rectangular frame member that holds a cooling device. The opposite ends of the energy absorbing member may be attached near a connecting portion of an upper edge and a side edge of the frame member.

A bumper beam may be provided below the energy absorbing member. A front end of the energy absorbing member may be disposed so as to protrude toward a vehicle front side beyond a straight line connecting the front end of the hood and the front end of the bumper beam.

The front side of the energy absorbing member may have concave and convex shapes extending in the vehicle width direction.

DETAILED DESCRIPTION

An implementation of a vehicle front body structure according to the invention will be described below by referring toFIG. 1throughFIG. 6. The vehicle front body structure of the implementation is disposed on a front section of a vehicle such as a passenger car.

InFIG. 1throughFIG. 4, vehicle exterior members and an engine, auxiliary equipment, suspension and the like are omitted from the drawings in order to make it easy to understand the implementation.

A vehicle front body structure1includes a pair of front side frames10, a radiator panel20, a strut container30, a front upper frame40, a hood50(seeFIG. 5), a bumper face60(seeFIG. 5), a bumper beam70(seeFIG. 5), an energy absorbing member100, and the like.

The front side frames10extend substantially along the longitudinal direction of the vehicle, and are spaced apart from each other in the vehicle with. They are main structural members of the vehicle body. Each front side frame10protrudes toward the vehicle front side from a lower end of a toe board (not shown) that is used as a partition between a vehicle cabin and an engine compartment at the vehicle front side. The front side frames10are disposed along the right and left sides of the engine compartment. Each front side frame10has a closed rectangular shape in cross section when viewed from the vehicle front side.

The radiator panel20has a frame-like shape and is attached to a front end of the front side frame10. The radiator panel20holds a radiator core and a condenser for an air conditioner, which are not shown in the drawings. The radiator panel20includes a radiator panel side member21, a radiator panel upper member22, a radiator panel lower member23, a center member24.

The radiator panel side members21constitute the right and left sides of the radiator panel20. Each radiator panel side member21is formed to have a column-like shape that extends in a vertical direction. The radiator panel side member21at its outer side in the vehicle width direction and at intermediate portion in the vertical direction is connected to the front side frame10at its inner side surface in the vehicle with direction and in the vicinity of the front end of the frame10.

The radiator panel upper member22couples upper ends of the right and left radiator panel side members21. The radiator panel upper member22has a beam-like shape that extends in the vehicle width direction.

The radiator panel lower member23couples lower ends of the right and left radiator panel side members21. The radiator panel lower member23has a beam-like shape that extends in the vehicle width direction.

The center member24connects the radiator panel upper member22and the radiator panel lower member23in the vertical direction at their intermediate portions in the vehicle width direction.

A hood catcher (not shown) that locks a front end of the hood50is attached to a central part of the radiator panel upper member22in the vehicle width direction.

The strut container30contains a strut disposed on a MacPherson strut front suspension (not shown). The strut container30protrudes upward in the vertical direction and outward in the vehicle width direction from an outer part in the vehicle width direction at a rear part of the front side frame10. A strut upper mount31disposed on an upper end of the strut container30supports an upper end of the strut so that the strut can rotate around a central axis of a rod.

The front upper frame40couples an upper part of the strut container30and a side end of the radiator panel upper member22together with a headlight upper member41. The front upper frame40protrudes forward from an upper part of the strut container30. A front end of the front upper frame40is connected to the headlight upper member41that holds an upper part of a headlight unit (not shown). The headlight upper members41protrude outward in the vehicle width direction from right and left side ends of the radiator panel upper member22.

The hood50shown inFIG. 5andFIG. 6is a lid that is openable and closable on an upper part of the engine compartment. The hood50is attached to the vehicle body pivotally around a hinge (not shown) provided on a rear end of the hood50. A striker (not shown) that engages with the hood catcher attached to the radiator panel upper member22is provided on a lower part of the hood50near a front end thereof. The hood50is provided on its front end with a seal51made of rubber.

The bumper face60illustrated inFIG. 5andFIG. 6is an exterior member made of a resin material such as a polypropylene (PP) base resin. The bumper face60is disposed on a front end part of the vehicle. An upper end of the bumper face60is disposed adjacent to a front end part of the hood50. The bumper face60is provided on its front face with a grill61that takes in a vehicle-travelling wind.

The bumper beam70opposes a rear side of the bumper face50in the vehicle longitudinal direction and has a beam-like shape that extends substantially in the vehicle width direction. The bumper beam70transmits a load at a head-on collision of the vehicle. The rear side of the bumper beam70is coupled through a stay (not shown) to a front end of the front side frame10. The bumper beam70is formed by, for example, assembling panels made of press-molded steel sheets so as to have a closed cross section. An energy absorbing element71made of, for example, a foamed material is attached to a front side of the bumper beam70and protrudes forward in the vehicle longitudinal direction.

The energy absorbing member100protrudes toward the front side of the vehicle from the radiator panel upper member22and absorbs energy through deformation upon a collision between the vehicle and the femoral region of a pedestrian and a light collision between the vehicle and another vehicle. The energy absorbing member100includes a base panel110, a bracket120, a main body130, and the like. These members are formed with panels made of press-molded steel sheets and are connected with one another by spot welding or the like.

The base panel110is a panel-like member and a base to which the main body130is attached. The base panel110extends substantially along the vertical direction and the vehicle width direction. An upper part of the base panel110protrudes forward from a lower part of the base panel110in a stepped shape. An upper end of the base panel110is secured to an upper end of the bumper face60.

The bracket120connects right and left side ends of the base panel110with a connecting portion (corner) between a side end of the radiator panel upper member22of the radiator panel20and an upper end of the radiator panel side member21. The bracket120is disposed so as to protrude toward a vehicle rear side from a rear end of the base panel110.

The main body130is disposed on a front side of the base panel110so as to protrude forward and is mainly used to absorb energy upon a collision. As illustrated inFIG. 5andFIG. 6, the main body130includes a front side131, an upper side132, a lower side133, and the like, which are integrally formed.

The front side131has a surface extending along the vertical direction and the vehicle width direction. The front side131opposes and is spaced apart from a rear side near the upper end of the bumper face60. The front side131is provided on its lower part with a rib131athat protrudes toward the front side of the vehicle. The rib131ais extends over substantially the whole length of the main body130in the longitudinal direction (right and left directions) of the main body130. A front end of the rib131ais disposed so as to protrude toward the front side of the vehicle ahead of a straight line L (seeFIG. 6) that connects the front end of the hood50and the front end of the energy absorbing element71of the bumper beam70.

The upper side132protrudes toward a rear side from an upper end of the front side131. The upper side132is provided on its rear end with a flange132athat protrudes upward. The flange132ais secured to an upper part on the front side of the base panel110by, for example, spot welding.

As illustrated inFIG. 6, an edge line132bis disposed on the upper side132at its intermediate part in the vehicle longitudinal direction and at its opposite ends in the vehicle width direction. The edge line132bis formed by bending the upper side132so as to define a convex shape at the top face of the upper side132. The edge line132bextends substantially along the vehicle width direction. When a compressive load is applied to the main body130in the vehicle longitudinal direction, the edge line132bfunctions as the weak portion to induce a buckling deformation of the upper side132.

A patch or a doubler (not shown) may be provided on a rear surface on a connecting portion between the front side131and the upper side132so as to increase stiffness of a front end part of the energy absorbing member and to accelerate a response to a load at the beginning of a collision.

The lower side133protrudes toward a rear side from a lower end of the front side131. The lower side133is provided on it rear end with a flange133athat protrudes downward. The flange133ais secured to a lower part of the front side of the base panel110by, for example, spot welding.

The front side131is formed in a slightly curved shape such that a vehicle front side is convex in plan view.

A space130ais provided on the back side of the main body130at its central part in the vehicle width direction. The space130ais defined by forming rear edges of the upper side132and the lower side133in an arch-like shape being concave toward front. Rear edges of the upper side132and the lower side133in the space130aare opposed to and spaced apart from the base panel110. The edge line132bon the upper side132is separated apart by the space130aso as to be arranged on both sides of the space130a.

Next, behaviors and operational effects in the above implementation at a collision will be described below.

FIG. 7AthroughFIG. 7Care schematic views of the energy absorbing member of the vehicle front body structure in the implementation of the invention upon a collision between the energy absorbing member and the femoral region of a pedestrian.FIG. 7Ais a schematic plan view of the energy absorbing member, illustrating a collision between a central part of the main body of the energy absorbing member in a vehicle width direction and an impactor that simulates the femoral region of the pedestrian.

An impactor I has a column-like shape that simulates the size, mass, hardness, and the like of the femoral part region of a pedestrian. At a collision between the impactor I and a central part of the main body130, the central part of the main body130deforms and bends so that the central part is retracted with respect to the opposite side ends of the main body130and the space130ais narrowed. This deformation absorbs energy at a collision. At this time, since the rib131aon the front side131suppresses local deformation of the main body130, the rib131atransmits a load in the vehicle width direction.

FIG. 7Bis a schematic plan view of the energy absorbing member, illustrating a collision between a side end part of the main body of the energy absorbing member in the vehicle width direction and the impactor that simulates the femoral region of the pedestrian.FIG. 7Cis a cross-sectional view of the main body of the energy absorbing member taken along a line VIIC-VIIC inFIG. 7B.

Although the main body130of the energy absorbing member100deforms in a bent state upon a collision between the impactor I and a side end part of the main body130, the central part of the main body130tends to be negligibly deformed.

Thus, in the implementation, upon a collision between the impactor I and a side end part of the main body130, the main body130absorbs the energy by buckling and deforming the upper side132and the lower side133, as illustrated inFIG. 7C. Accordingly, the main body130adjusts load generated at a collision between the impactor I and a central part of the main body130and load generated at a collision between the impactor I and an end part of the main body130to be substantially uniform.

As illustrated inFIG. 7C, when a compressive load of a certain value or higher is applied to the main body130in the vehicle longitudinal direction, the upper side132is buckled and deformed so as to be convex upward while the lower side133is buckled and deformed so as to be convex downward. The upper side132is adjusted with the edge line132bsuch that the upper side132reduces the load which causes buckling deformation and reduces the load transmitted to the bracket120, the radiator panel20, and the like.

FIG. 8is a schematic plan view of the main body of the energy absorbing member for the vehicle front body structure according to the implementation, illustrating the action of the energy absorbing member upon a light collision between the vehicle and another vehicle.FIG. 8is a schematic view of the energy absorbing member, illustrating a light collision between a barrier B that simulates another vehicle and a central part of the main body130of the energy absorbing member100in the vehicle width direction. The barrier B applies a load to the front side131of the main body130over a relatively wide range in the vehicle width direction.

Thus, a central part of the main body130is retracted with respect to the side ends of the main body130and is bent and deformed so that the space130ais narrowed and as a result the energy is absorbed. Furthermore, energy that the deformation of the main body130cannot absorb can be absorbed by cross-sectional deformation, as is the case with the cross-sectional deformation illustrated inFIG. 7C. At this time, the load transmitted from the side ends of the upper side132and the lower side133of the main body130to the base panel110and the bracket120is set to be a certain value or smaller so that the radiator panel20does not cause fracture and deformation.

As described above, the implementation can obtain the following effects.

(1) Since the rear edge of the main body130is formed in an arch-like shape so as to define the space130abetween the main body130and the base panel110, the central part of the main body130is bent and deformed in the rear direction of the vehicle at a collision between the vehicle and the femoral region of a pedestrian and at a light collision between the vehicle and another vehicle, and the main body130can absorb the energy. At this time, since the main body130does not press other parts on the rear side such as the hood catcher, thereby preventing the other parts from suffering any damage.

(2) In the case where the energy cannot be sufficiently absorbed by only the deformation of the main body130, the regions in the vicinity of the side ends of the upper side132and the lower side133can be buckled and deformed, thereby effectively absorbing the energy at a collision between the main body130in the vicinity of the side ends of the main body130and the femoral region of a pedestrian and at a light collision between the vehicle and another vehicle. Also, even if the position in the main body with which the femoral region of the pedestrian collides is shifted in the vehicle width direction, it is possible to prevent the load from being severely changed and to enhance protection for a pedestrian.

(3) The main body130is provided on the front side131with the rib131awhich extends in the vehicle width direction. Therefore, even if a collision between the femoral region of the pedestrian and a local part of the main body occurs, it is possible to disperse the load in the vehicle width direction, thereby effectively absorbing the energy.

The invention is not limited to the implementation described above and various alterations and modifications may be made, which are also fall within the technical scope of the invention.

For example, shapes, structures, materials, and manufacturing methods of the respective members that constitute the vehicle front body structure are not limited to the above implementation, and may be altered, as appropriate.