Vehicle front part structure

Abstract

To ensure collision performance while increasing rigidity of a vehicle front part.SOLUTION: In a vehicle front part structure S, lower crash boxes 40 are provided in front of front side portions 18B2 and are curved in an arc shape that is inclined upward and protrudes upward in a direction toward the outer side in a vehicle width direction in a front view. Accordingly, at the time of a front collision, the lower crash boxes 40 push up a cross member 30 via the front side portions 18B2 and outer connecting portions 31. Therefore, the connection between the cross member 30 and a front side frame 10 can be properly released at the time of the front collision. As a result, the cross member 30 can be prevented from impeding compressive deformation of the front side frame 10 at the time of the front collision. Meanwhile, during the time of a small lap collision, an effective reaction force can be applied to the colliding body from a subframe 18, the outer connecting portions 31, and the cross member 30.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a vehicle front structure. [Background technology]

[0002] In the vehicle front structure disclosed in Patent Document 1 below, a cross member extends in the vehicle width direction and spans the front ends of a pair of left and right front side members. This allows the cross member to increase the rigidity of the vehicle front. The cross member is also located on the inside of the front side members in the vehicle width direction, and both longitudinal ends of the cross member are joined to the sides of the front side members. This allows the front ends of the front side members to be supported from the inside of the vehicle width direction by the cross member. As a result, in a small overlap collision in which a colliding object collides with the outside of the front side frames in the vehicle width direction, the cross member supports the front side members from the inside of the vehicle width direction, thereby preventing bending of the front side members. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-44911 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the above-described vehicle front structure leaves room for improvement in the following respects. Specifically, in the above-described vehicle front structure, as described above, the cross member is connected to the front end portions of the front side members. Therefore, the cross member may impede compressive deformation of the front end portions of the front side members during a frontal collision of the vehicle. In other words, during a frontal collision of the vehicle, the portions of the front side members connected to the cross member may not undergo satisfactory compressive deformation. In this case, the collision energy absorption performance of the front side members may be reduced.

[0005] SUMMARY OF THE INVENTION In consideration of the above, an object of the present invention is to provide a vehicle front structure that can increase the rigidity of the vehicle front while ensuring collision performance. [Means for solving the problem]

[0006] One or more embodiments of the present invention include a pair of left and right front side frames extending in the front-rear direction of the vehicle on both sides in the vehicle width direction of a front part of the vehicle; a cross member extending in the vehicle width direction above the front side frames and connected to the pair of left and right front side frames, and which is released from its connected state to the front side frames by a load input during a frontal collision of the vehicle; outer connecting portions provided at both longitudinal ends of the cross member and extending from the cross member to the underside of the vehicle on the outer sides of the front side frames in the vehicle width direction; a pair of left and right side portions provided below the front side frames and extending in the front-rear direction of the vehicle; and a pair of left and right lower crash boxes provided on the front side of the front section, wherein the front section includes a front center section extending in the vehicle width direction, and a pair of left and right front side sections extending outward in the vehicle width direction from both longitudinal ends of the front center section, with lower ends of the outer connecting sections joined to outer ends in the vehicle width direction, the lower crash boxes extending from the front side sections to the front of the vehicle, and the lower crash boxes and the front side sections inclined upward on the vehicle as they went outward in the vehicle width direction when viewed from the front of the vehicle. [Effects of the Invention]

[0007] According to one or more embodiments of the present invention, it is possible to ensure collision performance while increasing the rigidity of the front part of the vehicle. [Brief explanation of the drawings]

[0008] [Figure 1]1 is a plan view seen from above, schematically showing the front part of a vehicle to which a vehicle front structure according to an embodiment of the present invention is applied. [Figure 2] 2 is a side view of the front part of the vehicle shown in FIG. 1 as seen from the left side of the vehicle. [Figure 3] 2 is a front view of the front part of the vehicle shown in FIG. 1 as seen from the front side of the vehicle. [Figure 4] 2 is a bottom view of the front part of the vehicle shown in FIG. 1 as seen from below the vehicle. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, a vehicle (automobile) V to which a vehicle front structure S according to this embodiment is applied will be described with reference to the drawings. In the drawings, the front side of the vehicle V is indicated by an arrow FR, the upper side of the vehicle is indicated by an arrow UP, and the left side of the vehicle (one side in the vehicle width direction) when viewed from above the vehicle is indicated by an arrow LH. In addition, in the following description, when the up-down, front-rear, and left-right directions are used, they refer to the up-down direction of the vehicle, the front-rear direction of the vehicle, and the left-right direction of the vehicle unless otherwise specified.

[0010] As shown in Figures 1 to 4, a vehicle front structure S is applied to the front of a vehicle V. The vehicle front structure S has a pair of left and right front side frames 10, a bumper beam 16, a subframe 18, a radiator core 20, a cross member 30, and a pair of left and right lower crash boxes 40. Each component of the vehicle front structure S will be described below.

[0011] The pair of front side frames 10 are formed in the shape of hollow, approximately rectangular pillars extending in the front-to-rear direction, and are arranged on both sides in the vehicle width direction (on both sides in the left-to-right direction) of a power unit compartment 12 at the front of the vehicle V. Crash boxes 14 are provided in front of the front side frames 10. The crash boxes 14 are formed in the shape of approximately rectangular cylinders with their axial directions extending in the front-to-rear direction, and the rear ends of the crash boxes 14 are connected to the front ends of the front side frames 10.

[0012] The bumper beam 16 extends in the vehicle width direction and forms a framework at the front end of the vehicle V. The bumper beam 16 is formed in a substantially rectangular frame shape in a cross section seen from the longitudinal direction of the bumper beam 16. That is, the bumper beam 16 has a rectangular closed cross-sectional structure. The bumper beam 16 is connected to the front end portions of the crash boxes 14 with both end portions of the bumper beam 16 in the vehicle width direction protruding outward in the vehicle width direction beyond the front side frames 10. In this way, the bumper beam 16 is connected to the front side frames 10 via the crash boxes 14. Note that the crash boxes 14 may be omitted and the bumper beam 16 may be directly connected to the front end portions of the front side frames 10.

[0013] The subframe 18 is provided below the front side frames 10 and constitutes the lower end of the framework at the front of the vehicle V. The subframe 18 is formed in a generally rectangular ring shape in a plan view. Specifically, the subframe 18 has subframe side portions 18A as a pair of left and right side portions, and a subframe front portion 18B as a front portion that extends in the vehicle width direction and connects the front ends of the subframe side portions 18A. The subframe side portions 18A are formed in a generally hollow column shape that extends in the front-to-rear direction, and are connected to the front side frame 10 by brackets (not shown). An inclined portion 18A1 is formed at the front end of the subframe side portion 18A, and the inclined portion 18A1 is inclined upward as it approaches the front in a side view.

[0014] The subframe front portion 18B has a front center portion 18B1 that forms the longitudinal center of the subframe front portion 18B, and a pair of left and right front side portions 18B2 that form both longitudinal ends of the subframe front portion 18B. The front center portion 18B1 extends linearly in the vehicle width direction. The vertical position of the front center portion 18B1 substantially coincides with the vertical position of the subframe side portions 18A. The front side portions 18B2 extend outward in the vehicle width direction from both longitudinal ends of the front center portion 18B1. In a front view, the front side portions 18B2 are inclined upward as they extend outward in the vehicle width direction, and are curved in a substantially arc-like shape that is convex upward (see FIG. 3). The inclined portions 18A1 of the subframe side portions 18A are disposed rearward of the front side portions 18B2 and are connected to the outer ends of the front side portions 18B2 in the vehicle width direction.

[0015] The radiator core 20 is a cooling device for cooling a power unit (not shown) of the vehicle V and the like. The radiator core 20 is formed in a generally rectangular, flat shape overall, and is disposed between the front ends of a pair of left and right front side frames 10 in a rearwardly tilted state. Specifically, the radiator core 20 is tilted rearward as it extends upward in a side view. A lower end (front end) of the radiator core 20 is supported from below by a subframe front portion 18B of the subframe 18 via a mount member (not shown). An upper end portion (rear end portion) of the radiator core 20 is supported by a second cross member (not shown).

[0016] The cross member 30 is formed in a hollow, generally rectangular pillar shape extending in the vehicle width direction. The cross member 30 is disposed adjacent to the upper side of the front side frame 10, and the lower wall of the cross member 30 is joined to the upper wall of the front side frame 10 by welding or the like.

[0017] Both longitudinal ends of the cross member 30 protrude outward in the vehicle width direction beyond the front side frames 10. Outer connecting portions 31 are provided at both longitudinal ends of the cross member 30. The outer connecting portions 31 are formed in a substantially rectangular tubular shape with the axial direction extending in the up-down direction, and extend downward from the cross member 30 outside the front side frames 10 in the vehicle width direction. The lower end of the outer connecting portion 31 is located below the front side frames 10, and is joined by welding or the like to the outer end of the front side portion 18B2 of the subframe 18 in the vehicle width direction.

[0018] Additionally, inner connecting portions 32 are provided at both longitudinal end portions of the cross member 30. The inner connecting portions 32 are formed in a generally rectangular tubular shape with the vertical axis as the axial direction, and extend downward from the cross member 30 on the inner side of the front side frame 10 in the vehicle width direction. The lower end of the inner connecting portion 32 is located below the front side frame 10, and is joined to the front side portion 18B2 of the subframe 18 by welding or the like.

[0019] The cross member 30 is located above the lower end portion of the radiator core 20 and is located in front of the upper part of the radiator core 20. In other words, the cross member 30 is located below the upper end of the radiator core 20, and the cross member 30 overlaps with the radiator core 20 in both a front view and a plan view. In addition, a lower rear corner of the cross member 30 is located above and in close proximity to the front of the vertical middle portion of the radiator core 20.

[0020] Furthermore, as will be described in detail later, in the event of a frontal collision of the vehicle V, a collision load to the rear of the vehicle and an upward load caused by deformation of the lower crash boxes 40, which will be described later, are input to the cross member 30. The loads input to the cross member 30 are then set to release the joined (connected) state between the cross member 30 and the front side frame 10.

[0021] A trunk room 26 is provided at the front end of the power unit compartment 12 of the vehicle V. The trunk room 26 is formed in a recessed shape that is open to the upper side, and is disposed above the radiator core 20. A hood 28 is also provided at the front of the vehicle V. The hood 28 is formed in the shape of a substantially rectangular panel with its thickness direction extending in the up-down direction, and is provided at the front of the vehicle V in a state in which the power unit compartment 12 of the vehicle V is closed from above.

[0022] The lower crash boxes 40 are formed in a generally hollow, flat rectangular shape and are disposed in front of the front side portions 18B2 of the subframe 18. Like the front side portions 18B2, the lower crash boxes 40 are inclined upward as they extend outward in the vehicle width direction in a front view and are curved in a generally arc-like shape that is convex upward. The rear ends of the lower crash boxes 40 are joined to the front ends of the front side portions 18B2. In other words, the lower crash boxes 40 are supported from the rear by the subframe 18. The outer shape of the lower crash boxes 40, as viewed from the front, generally matches the outer shape of the front side portions 18B2.

[0023] (Action and effect) Next, the behavior of the front part of the vehicle V in a frontal collision and a small wrap collision of the vehicle V will be explained, and the operation and effect of this embodiment will be explained.

[0024] In a frontal collision of vehicle V, a colliding object collides with the front end of vehicle V. As a result, a collision load to the rear of the vehicle is input to bumper beam 16, and the collision load compresses and deforms crash boxes 14. As a result, the crash load is absorbed by crash boxes 14.

[0025] In this case, the colliding object collides with the front ends of the lower crash boxes 40, and a rearward collision load is input to the front ends of the pair of lower crash boxes 40. The pair of lower crash boxes 40 are formed in a generally hollow, flat shape, and are inclined upward and curved in an upwardly convex arc as they extend outward in the vehicle width direction in a front view. The rear ends of the lower crash boxes 40 are supported by the front side portions 18B2 of the subframe 18. Therefore, when a rearward collision load is input to the front ends of the lower crash boxes 40, the lower crash boxes 40 behave in a twisting downward manner. Specifically, the lower crash boxes 40 are deformed so that the front ends of the vehicle width outer portions of the lower crash boxes 40 descend (see arrow A in FIG. 3 ) and the rear ends of the vehicle width outer portions of the lower crash boxes 40 ascend. As a result, the lower crash boxes 40 act to push up the cross member 30 via the front side portions 18B2, the outer connecting portions 31, and the inner connecting portions 32. In other words, an upward load F (see FIG. 3) is input to both longitudinal ends of the cross member 30.

[0026] Furthermore, when a colliding object enters the power unit compartment 12, the front ends of the crash boxes 14 and the front side frames 10 are compressively deformed and collide with the cross member 30. As a result, a collision load acts on the cross member 30 from the rear. As described above, an upward load F due to the deformation of the lower crash boxes 40 acts on the cross member 30 via the outer connecting portion 31 and the inner connecting portion 32. As a result, a shear force in the fore-and-aft direction and a force for peeling the cross member 30 upward from the front side frame 10 act on the joint between the cross member 30 and the front side frame 10. As a result, the joint between the cross member 30 and the front side frame 10 is broken, and the joint between the cross member 30 and the front side frame 10 is released.

[0027] In a small lap collision of the vehicle V, the impact body collides with the front end of the vehicle V on the vehicle width outer side of the front side frame 10. Therefore, the impact body collides only with the vehicle width outer end of the lower crash box 40. As a result, the impact body penetrates rearward while tearing off the vehicle width outer end of the lower crash box 40.

[0028] Furthermore, outer coupling portions 31 are provided on the outer sides of the front side frames 10 in the vehicle width direction, and the outer coupling portions 31 couple the cross member 30 and the subframe 18. Therefore, a collision object intruding from the rear collide with the subframe 18, outer coupling portions 31, and cross member 30, and a reaction force acts on the collision object from the subframe 18, outer coupling portions 31, and cross member 30. As described above, in the event of a small lap collision of the vehicle V, the reaction force can be effectively applied to the collision object from the subframe 18, outer coupling portions 31, and cross member 30. Therefore, the subframe 18, outer coupling portions 31, and cross member 30 can suppress the collision object from intruding rearward.

[0029] As described above, in the vehicle front structure S, the cross member 30 extending in the vehicle width direction is bridged over the pair of left and right front side frames 10 above the front side frames 10. This allows the front ends of the front side frames 10 to be connected by the cross member 30. In addition, the outer connecting portion 31 extends downward from the cross member 30 on the vehicle width direction outer side of the front side frame 10 and is connected to the vehicle width direction outer end of the front side portion 18B2 of the subframe 18. This allows the rigidity of the front portion of the vehicle V to be increased.

[0030] A pair of left and right lower crash boxes 40 are provided in front of the front side portions 18B2 of the subframe 18. The lower crash boxes 40 are formed in a hollow, flat shape and, in a front view, slope upward toward the outside in the vehicle width direction and are curved in an upwardly convex arc. Therefore, as described above, during a frontal collision of the vehicle V, the lower crash boxes 40 push up the cross member 30 via the front side portions 18B2 and the outer connecting portions 31. As a result, during a frontal collision of the vehicle V, in addition to the rearward collision load, a force that separates the cross member 30 upward from the front side frame 10 can be applied to the cross member 30. This effectively releases the connection between the cross member 30 and the front side frame 10. As a result, the cross member 30 is prevented from impeding compressive deformation of the front side frame 10 during a frontal collision. In other words, the joint portion of the front side frame 10 with the cross member 30 can be effectively compressed and deformed. On the other hand, in the event of a small lap collision, an effective reaction force can be applied to the colliding body from the subframe 18, the outer connecting portion 31, and the cross member 30. As a result, the front rigidity of the vehicle V can be increased while ensuring collision performance.

[0031] As described above, the lower crash boxes 40 are inclined upward and curved in an upwardly convex arc as they extend outward in the vehicle width direction in a front view. This allows the lower crash boxes 40 to bend downward favorably in the event of a frontal collision of the vehicle V. As a result, an upward load can be applied from the lower crash boxes 40 to the cross member 30 via the subframe 18 and the outer connecting portion 31.

[0032] The cross member 30 is also provided with an inner connecting portion 32. The inner connecting portion 32 extends downward from the cross member 30 on the inner side of the front side frame 10 in the vehicle width direction, and the lower end of the inner connecting portion 32 is joined to the front side portion 18B2 of the subframe 18. As a result, in the event of a frontal collision of the vehicle V, an upward load F can be applied to the cross member 30 via the inner connecting portion 32 and the outer connecting portion 31. In other words, an upward load can be applied to the cross member 30 from both sides of the front side frame 10 in the vehicle width direction. As a result, the connection between the cross member 30 and the front side frame 10 can be more effectively released in the event of a frontal collision of the vehicle V.

[0033] Furthermore, in the vehicle V, the radiator core 20 is provided between the front side frames 10 at the front end of the power unit compartment 12, and is inclined rearward as it extends upward in a side view. This makes it possible to effectively secure space for installing a trunk room 26 at the front end of the power unit compartment 12.

[0034] In addition, the cross member 30, which is bridged across the pair of left and right front side frames 10, is located above the radiator core 20. Therefore, the space above the inclined radiator core 20 can be effectively utilized to position the cross member 30. This allows the installation space for the cross member 30 and the radiator core 20 to be made more compact.

[0035] In this embodiment, the lower crash boxes 40 are curved in an arc shape that is convex upward and inclined upward as they extend outward in the vehicle width direction when viewed from the front. That is, the lower crash boxes 40 are curved in a curved shape when viewed from the front. Alternatively, the lower crash boxes 40 may be curved in a linear shape that extends upward as they extend outward in the vehicle width direction when viewed from the front.

[0036] In addition, in this embodiment, the cross member 30 and the subframe 18 are connected by the outer connecting portion 31 and the inner connecting portion 32, but the inner connecting portion 32 may be omitted and the cross member 30 and the subframe 18 may be connected by the outer connecting portion 31. [Explanation of symbols]

[0037] 10 Front side frame 18 Subframe 18A Subframe side (side) 18B Subframe front section (front section) 18B1 Front center section 18B2 Front side 30 Cross member 31 Outer connection part 32 Inner connection part 40 Lower crash box S Vehicle front structure V vehicle

Claims

1. a pair of left and right front side frames extending in a front-to-rear direction of the vehicle on both sides in a vehicle width direction of a front portion of the vehicle; a cross member extending in a vehicle width direction above the front side frames, connected to the pair of left and right front side frames, and released from its connection with the front side frames by a load input during a frontal collision of the vehicle; outer connecting portions provided at both longitudinal end portions of the cross member and extending from the cross member toward the underside of the vehicle on the outer sides of the front side frames in the vehicle width direction; a subframe including a pair of left and right side portions provided below the front side frames and extending in a vehicle longitudinal direction, and a front portion extending in a vehicle width direction and connecting front ends of the side portions; a pair of left and right lower crash boxes provided on the front side of the vehicle in the front portion; Equipped with The front portion is a front center portion extending in the vehicle width direction; a pair of left and right front side portions extending outward in the vehicle width direction from both longitudinal end portions of the front center portion, with lower end portions of the outer connecting portions being joined to outer end portions in the vehicle width direction; The invention comprises: the lower crash box extends from the front side portion toward the front of the vehicle, The vehicle front structure is such that the lower crash boxes and the front side portions are inclined upward toward the outside in the vehicle width direction when viewed from the front of the vehicle.

2. 2. The vehicle front structure according to claim 1, wherein the lower crash box and the front side portion are curved in an arc shape that convex upwardly of the vehicle when viewed from the front side of the vehicle.

3. The cross member is provided with an inner connecting portion, 3. The vehicle front structure according to claim 2, wherein the inner connecting portion extends from the cross member toward the underside of the vehicle on the vehicle width direction inner side of the front side frame, and a lower end of the inner connecting portion is connected to the front side portion.

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