JP2017047748A - Vehicle front part structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle front part structure that suppresses vibration of a cabin without causing constraint in manufacturing, such as increase in the number of components and vehicle weight.SOLUTION: In the vehicle front part structure, adjusting shapes of beads 72A, 72B of a radiator support upper member 30 matches mount positions of front side members 12A, 12B of radiator support side members 28A, 28B with node positions of vehicle width direction vibration of the radiator support side members 28A, 28B in a frequency band containing a natural frequency of a vehicle body, thereby suppressing a vibration amount of the front side members 12A, 12B to suppress vibration of the cabin.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vehicle front structure.

  Conventionally, in order to suppress vehicle interior noise (road noise) due to vehicle body vibration caused by road surface input, vibration of each component and vibration transmission between components are reduced in the vibration transmission path from the tire to the vehicle interior. Has been attempted.

  For example, with respect to vibration in the vehicle width direction of the attachment point with respect to the radiator support of the front side member, which is one of the vibration transmission paths of road noise, the rigidity of the attachment point is improved by improving the rigidity of the radiator support lower member, It is intended to suppress the vibration of the front side member, and hence the vibration of the entire vehicle.

JP 2002-240744 A

  However, in order to improve the rigidity of the attachment point, it is necessary to increase the weight of the vehicle body by increasing the cross section of the component, increasing the plate thickness, adding welding points and connecting members, etc. Often introduces constraints.

  The present invention has been made in consideration of the above facts, and an object of the present invention is to provide a vehicle front structure that suppresses noise in a passenger compartment without causing manufacturing restrictions such as an increase in the number of parts and the weight of a vehicle body.

  The invention according to claim 1 is connected to the pair of front side members extending in the vehicle front-rear direction at both ends in the vehicle width direction at the vehicle front portion, and connected to the front end portions of the front side members, and extends in the vehicle vertical direction. A pair of left and right radiator support side members and upper ends of the radiator support side members are connected to each other, a radiator support upper member extending in a vehicle width direction is connected to each other, and lower ends of the radiator support side members are connected to each other. A radiator support lower member extending in a direction, a pair of left and right braces connecting the front end of each front side member and the radiator support upper member, and the radiator support in the vehicle width direction on the upper surface of the radiator support upper member Corresponds to the fixed position of the brace of the upper member Is formed in a position comprises a bead extending in the longitudinal direction the vehicle, a.

  This vehicle front structure is provided with a pair of braces that connect the front end of each front side member and the radiator support upper member. A bead extending in the vehicle front-rear direction is formed at a position corresponding to the brace fixing position of the radiator support upper member in the vehicle width direction. By providing this bead, the rigidity (hardness to deform) of the radiator support upper member in the vehicle width direction (hereinafter referred to as “right / left rigidity”) can be adjusted. Therefore, by adjusting the left and right rigidity of the radiator support upper member, the position of the vibration in the vehicle width direction of the radiator support side member determined by the relationship between the left and right rigidity of the radiator support upper member and the radiator support lower member is connected to the radiator support side member. The amount of vibration of the front side member (in the vehicle width direction) can be suppressed by setting the same height as the fixed position of the front side member (in the vehicle vertical direction). That is, by suppressing the amount of vibration of the front side member, which is one of the road noise vibration transmission paths, it is possible to suppress noise (road noise) in the vehicle interior.

  Also, for example, when the front-side member vibration in the vehicle front-rear direction and the radiator support upper member vibration in the vehicle front-rear direction are in opposite phases, the radiator support that deforms by torsion by reducing the left-right rigidity of the radiator support upper member By increasing the amount of vibration of the upper member in the vehicle front-rear direction, the amount of vibration of the front side member in the vehicle front-rear direction can be suppressed, and noise in the passenger compartment can be reduced. On the other hand, when the vibration in the vehicle longitudinal direction of the front side member and the vibration in the vehicle longitudinal direction of the radiator support upper member are in phase, the radiator support upper member that is torsionally deformed by increasing the lateral rigidity of the radiator support upper member. By reducing the amount of vibration in the vehicle front-rear direction, the amount of vibration in the vehicle front-rear direction of the front side member can be suppressed, and noise in the vehicle interior can be reduced.

  Since the vehicle front structure according to the first aspect of the present invention has the above-described configuration, it is possible to suppress noise in the vehicle interior without causing an increase in the weight of the vehicle body or restricting the arrangement of parts.

It is a perspective view which shows the vehicle front part structure which concerns on one Embodiment of this invention. (A) is a vehicle longitudinal cross-sectional view in the vehicle width direction center part of a radiator support upper, (B) is a vehicle longitudinal cross-sectional view in the V brace attachment position of a radiator support upper. It is a front view showing the vehicle front part structure concerning one embodiment of the present invention. It is a front view which shows the deformation | transformation state in the shear deformation mode of the vehicle front part structure which concerns on a comparative example. It is a side view showing the vehicle front part structure concerning one embodiment of the present invention. It is a side view which shows the deformation | transformation state in the shear deformation mode of the vehicle front part structure which concerns on a comparative example. It is a front view which shows the deformation | transformation state in the vehicle front part structure which concerns on one Embodiment of this invention. (A) is a principal part front view which shows the deformation | transformation state in the vehicle front part structure which concerns on one Embodiment of this invention, (B) is a schematic diagram which shows the principle of the effect | action. (A), (B) is a vehicle front-back direction sectional drawing which shows the cross-sectional deformation state of the radiator support upper which concerns on a comparative example and this embodiment, respectively. It is a side view which shows the deformation | transformation state in the vehicle front part structure which concerns on one Embodiment of this invention.

  A vehicle front structure according to an embodiment of the present invention will be described with reference to FIGS. In addition, each figure is typical and the illustration with a low relevance to the present invention is omitted. In each figure, the arrow FR indicates the front of the vehicle, the arrow W indicates the vehicle width direction, and the arrow UP indicates the upper side of the vehicle.

(Vehicle front structure)
As shown in FIG. 1, the vehicle front portion structure 10 of the present embodiment includes a pair of front side members 12A, 12B extending in the vehicle front-rear direction on both sides in the vehicle width direction of the vehicle front portion, and the front side member 12A. The radiator support 14 disposed between both ends of the front side members 12A and 12B and a pair of V braces 16A and 16B for connecting the front ends of the front side members 12A and 12B and the radiator support 14 are basically provided. .

  The front side member 12A is formed at the front side member main body 18A, the front end of the front side member main body 18A, a widening member 20A whose width in the vehicle width direction increases toward the front of the vehicle, and a front side of the widening member 20A. The crash box 22A is provided. A cap 24A is attached to the tip (vehicle front end) of the crash box 22A.

  Since the front side member 12B has the same configuration as that of the front side member 12A, the same components as those of the front side member 12A are denoted by the same reference numerals with B added thereto, and detailed description thereof is omitted.

  As shown in FIG. 1, the radiator support 14 includes a radiator support lower member 26 extending in the vehicle width direction, and a pair of radiator support side members 28A, 28B extending upward from the both ends of the radiator support lower member 26. And a radiator support upper member 30 disposed between upper ends (vehicle upper end portions) of the radiator support side members 28A and 28B and extending in the vehicle width direction. That is, the radiator support 14 is formed in a rectangular shape when viewed from the front of the vehicle.

  As shown in FIG. 1, between the radiator support side member 28B and the crash box 22B, a bracket 32B and a bracket 34B for connecting the two are disposed. The bracket 32B has a hat shape in cross section in a plan view of the vehicle (viewed from above the vehicle), and the top surface 36B is joined to the top surface 38B of the radiator support side member 28B by welding. The flange surface 40B of the bracket 32B is joined to the side surface 42B of the crash box 22B by welding.

  Further, the bracket 34B has an L-shaped cross section in a plan view of the vehicle, and a first surface 44B forming a long side thereof is joined to the side surface 46B of the radiator support side member 28B and the side surface 48B of the bracket 32B by welding. The second surface 50B forming the short side of the bracket 34B is overlapped with the flange surface 40B of the bracket 32B and joined to the side surface 42B of the crash box 22B by welding.

  In this way, the crash box 22B (front side member 12B) is fixed to the radiator support side member 28B (radiator support 14) via the brackets 32B and 34B.

  The radiator support side member 28A and the crash box 22A are also connected in the same configuration. In the figure, similar components are denoted by the same reference numerals with the reference symbol A and detailed description thereof is omitted.

  As shown in FIGS. 2A and 2B, the radiator support upper member 30 is provided with a substantially hat-shaped second member 54 on an upper portion of a substantially L-shaped first member 52 in the longitudinal cross section of the vehicle. Has been. 2A shows a cross section of the radiator support upper member 30 at the center in the vehicle width direction, and FIG. 2B shows a cross section at the V brace mounting position.

  The first member 52 includes a horizontal plane 56 that extends in the vehicle front-rear direction and a front surface 58 that extends downward from the vehicle front end of the horizontal plane 56. The second member 54 also includes an upper surface 60 extending in the vehicle front-rear direction, a front surface 62 extending from the vehicle front end portion of the upper surface 60 to the vehicle lower side, and a vehicle rear end portion of the upper surface 60 extending from the vehicle rear end to the vehicle lower side. A rear surface 64 and a flange surface 66 extending rearward from the vehicle lower end portion of the rear surface 64.

  The front surface 58 of the first member 52 and the front surface 62 of the second member 54 are joined, and the flange surface 66 of the second member 54 is joined to the vehicle rear end side of the horizontal surface 56 of the first member 52. The first member 52 and the second member 54 form a closed cross section.

  As shown in FIGS. 2A and 2B, the cross-sectional height of the radiator support upper member 30 is set such that the height H1 at the center in the vehicle width direction is higher than the height H2 at the V brace mounting position. Yes.

  As shown in FIG. 2B, the upper surface 60 of the radiator support upper member 30 is formed so that the front surface 62 (V brace mounting portion) side is lower than the rear surface 64 side at the V brace mounting position in the vehicle width direction. Yes.

  Further, as shown in FIG. 2 (B), holes 68 for fastening the V braces 16A and 16B are formed in the front surfaces 58 and 62 at the V brace mounting position. The hole 68 (V brace mounting position) is formed at a position offset from the cross-sectional center (height) of the closed cross-section formed in the radiator support upper member 30.

  As shown in FIGS. 1 and 3A, fastening seats 70A and 70B for fastening V-braces are formed in the vicinity of the center of the front surface 62 of the radiator support upper member 30 in the vehicle width direction. Further, beads (concave portions) 72A and 72B extending in the vehicle front-rear direction are formed at the same positions as the fastening seats 70A and 70B in the vehicle width direction of the upper surface 60.

  By adjusting the depth and width of the beads 72A and 72B, the left and right rigidity Ka of the radiator support upper member 30 is adjusted, and the ratio (Ka / Kb) to the left and right rigidity Kb of the radiator support lower member 26 is set to the radiator. In the support side members 28A and 28B, the ratio (LB / LA) is equal to the distance LA from the lower end to the mounting position of the front side members 12A and 12B (crash boxes 22A and 22B) to the distance LA from the upper end to the mounting position. (See FIGS. 6A and 6B).

  As shown in FIGS. 1 and 3A, an attachment member 74A for fastening a V brace is joined to the inner side in the vehicle width direction of the cap 24A of the crash box 22A by welding. The mounting member 74A has a substantially L-shaped cross section in a plan view of the vehicle, and a mounting surface 76A is formed on the vehicle rear side.

  The attachment member 74B has the same configuration as the attachment member 74A. In the figure, the same components are denoted by the same reference numerals with reference numerals B and detailed description thereof is omitted.

  The V brace 16A includes mounting portions 80A and 82A each having a flat plate shape at both ends of a substantially cylindrical main body portion 78A. Mounting holes 80A and 82A are formed with mounting holes, respectively. Therefore, one end of the V brace 16 </ b> A is fixed to the front surface 62 of the radiator support upper member 30 by fastening the attachment portion 80 </ b> A to the fastening seat 70 </ b> A of the radiator support upper member 30. Further, the other end of the V brace 16A is fixed to the mounting member 74A by fastening the mounting portion 82A to the mounting surface 76A of the mounting member 74A. As a result, the crash box 22A (front side member 12A) and the radiator support upper member 30 are connected via the V brace 16A.

  Since the relationship between the V brace 16B, the crash box 22B (front side member 12B), and the radiator support upper member 30 is the same, the same reference numbers with the same reference numbers with B added thereto are denoted by the same reference numerals. Detailed description is omitted.

  In FIG. 1, crash boxes 84 </ b> A and 84 </ b> B disposed at the vehicle front end portion of a second member (not shown) are disposed on the vehicle width direction outer side of both ends in the vehicle width direction of the radiator support lower member 26.

  Further, in FIGS. 3A and 4A, 86A and 86B are apron upper members, and 88A and 88B are extensions of the radiator support upper member 30. FIG.

(Deformation mode)
Here, in order to describe the operation of the present embodiment, a deformation mode using the vehicle front structure according to the comparative example will be described. In addition, about the component similar to this embodiment by a comparative example, the same referential mark is attached | subjected and the detailed description is abbreviate | omitted.

  Unlike the present embodiment, the comparative example has no bead formed on the upper surface 60 of the radiator support upper member 30. Further, as shown in FIG. 7A, the sectional height of the radiator support upper member 30 at the V brace mounting position is set equal to the sectional height at the center in the vehicle width direction (see FIG. 2A). Further, at the V brace mounting position of the radiator support upper member 30, a V brace fastening hole 68 is formed at the center position (height) of the closed section of the front surface 62. The vehicle front structure according to the comparative example has the same configuration as the vehicle front structure according to the embodiment except for these points.

  When vibration in the vehicle width direction in the frequency band including the natural frequency of the vehicle body is applied to the front mount of the front suspension member of the vehicle body having the vehicle front structure according to the comparative example, as shown in FIG. 3B, the radiator The support 14 is deformed as indicated by a solid line (after vibration) from a two-dot chain line (before vibration). That is, in the radiator support 14, the radiator support lower member 26, the radiator support side members 28A and 28B, and the radiator support upper member 30 are torsionally deformed. When joining positions of the radiator support upper member 30 and the radiator support side members 28A and 28B are points CA and CB, respectively, and joining positions of the radiator support lower member 26 and the radiator support side members 28A and 28B are points CC and CD, respectively. The points CA to CD are displaced as indicated by arrows A to D, respectively. Therefore, the radiator support 14 as a whole has a rectangular shape in front view, but is deformed into a substantially parallelogram. As a result, the radiator support upper member 30 is displaced to the right in the figure as indicated by arrows A and B, and the radiator support lower member 26 is displaced to the left in the figure as indicated by arrows C and D. . Further, the radiator support side member 28A moves on the upper right side obliquely downward (see arrow A) in the drawing, and on the lower side moves obliquely downward left on the drawing (see arrow C). In the radiator support side member 28B, the upper side moves to the upper right in the figure (see arrow B), and the lower side moves to the upper left in the figure (see arrow D).

  As a result, the front side member 12A (refer to the cap 24A) is displaced diagonally to the lower right in the figure, and the front side member 12B (refer to the cap 24B) is displaced obliquely to the upper right in the figure.

  Further, as shown in FIG. 4B, the radiator support 14 is deformed as indicated by a solid line (after vibration) from a two-dot chain line (before vibration) in the vehicle longitudinal direction. That is, the radiator support upper member 30 (the upper end of the radiator support side member 28A) is displaced to the vehicle rear side (see arrow E) by the torsional deformation. On the other hand, the front side member 12A (cap 24A) is displaced to the vehicle front side (see arrow F). That is, the radiator support upper member 30 and the front side member 12A are displaced in opposite phases in the vehicle front-rear direction. Similarly, the radiator support upper member 30 and the front side member 12B are displaced in opposite phases in the vehicle front-rear direction.

[Action]
The effect | action of the vehicle front part structure 10 which deform | transforms in this way is demonstrated.

(First action)
The ratio (Ka / Kb) of the left and right rigidity Ka of the radiator support upper member 30 and the left and right rigidity Kb of the radiator support lower member 26 by adjusting the depth and width of the beads 72A and 72B formed on the radiator support upper member 30. ) Is the ratio between the distance LB from the lower end to the mounting position of the front side members 12A and 12B (crash boxes 22A and 22B) to the distance LA from the upper end to the mounting position in the radiator support side members 28A and 28B (LB / LA). (See FIG. 6B).

  In this state, when the radiator support 14 vibrates due to vibration input from the road surface, the vehicle width direction vibration (hereinafter referred to as “left-right vibration”) of the radiator support side members 28A and 28B in the frequency band including the natural frequency of the vehicle body. The position P matches the mounting position (height) of the front side members 12A and 12B of the radiator support side members 28A and 28B. Therefore, as shown in FIG. 5, the radiator support 14 is greatly deformed as indicated by the solid line (after vibration) from the two-dot chain line (before vibration) by the input of vibration, but the front side members 12A, 12B (crash The left and right vibration (displacement) amounts R3 and R4 of the boxes 22A and 22B (see the caps 24A and 24B) are suppressed as compared with the left and right vibration amounts R1 and R2 (see FIG. 3B) according to the comparative example. As a result, the amount of left-right vibration of the front side members 12A and 12B, which is one of the components constituting the vibration transmission path to the vehicle interior, is reduced, and noise in the vehicle interior is reduced.

(Second action)
The upper surface 60 of the radiator support upper member 30 is higher than the height H1 in the cross section of the radiator support upper member 30 in the center in the vehicle width direction (see FIG. 2A). (See FIG. 2B) is set low. Further, in the upper surface 60, the height of the front surface 62 (V braces 16A and 16B attachment) side is set lower than that of the rear surface 64 side (see FIG. 7B). Furthermore, the vehicle vertical direction mounting position (hole portion 68) of the V braces 16A and 16B on the front surface 62 of the comparative example is positioned at the center (height) of the cross section of the radiator support upper member 30 (see FIG. 7A). On the other hand, in the present embodiment, the vehicle vertical direction mounting position (hole portion 68) of the V braces 16A and 16B on the front surface 62 is offset downward from the cross-sectional center (height) of the radiator support upper member 30. It is formed (see FIG. 7B).

  In this state, when the radiator support 14 vibrates due to vibration input from the road surface, the longitudinal rigidity (hardness of deformation in the vehicle longitudinal direction) of the radiator support upper member 30 at the mounting position of the V braces 16A and 16B decreases. Therefore, compared to the comparative example (see FIG. 7A), the cross-sectional collapse (the amount of deformation and displacement in the vehicle front-rear direction) becomes larger (see FIG. 7B), and as shown in FIG. The vibration (displacement) amount (D3) of the upper member 30 (the upper end of the radiator support side member 28A) in the vehicle front-rear direction increases compared to the displacement amount (D1 (see FIG. 4B)) of the comparative example. As a result, the vibration (displacement) amount (D4) in the vehicle front-rear direction of the front side members 12A and 12B vibrating in the opposite phase to the radiator support upper member 30 in the vehicle front-rear direction is the displacement amount (D2 (FIG. 4B (Refer to))).

  If the amount of vibration in the longitudinal direction of the vehicle of the radiator support upper member 30 which is deformed by torsion increases as a result of the adjustment of the beads 72A and 72B of the radiator support upper member 30, the adjustment of the beads 72A and 72B will also cause the increase. The amount of vibration of the front side members 12A and 12B can be suppressed.

(effect)
Thus, in the vehicle front structure 10 according to the present embodiment, the radiator support side member 28A in the frequency band in which the mounting positions of the front side members 12A and 12B of the radiator support side members 28A and 28B include the natural frequency of the vehicle body are provided. By providing the beads 72A and 72B of the radiator support upper member 30 (adjusting the depth etc.) so as to be the node position in the vehicle width direction vibration of 28B, the vibration in the vehicle width direction of the front side members 12A and 12B is suppressed. can do.

  Further, the amount of vibration of the radiator support upper member 30 in the vehicle front-rear direction is increased by adjusting the shape of the radiator support upper member 30 and changing the mounting position of the radiator support upper member 30 to increase the amount of vibration in the vehicle front-rear direction. It is possible to suppress the vibration of the front side members 12A and 12B that vibrate in the vehicle front-rear direction.

  That is, the vibration amount of the front side members 12A and 12B can be suppressed only by providing the beads 72A and 72B on the radiator support upper member 30 or by changing the shape of the radiator support upper member 30. Therefore, noise in the vehicle interior can be suppressed without causing an increase in the weight of the vehicle body or a restriction on the arrangement of parts.

  In the present embodiment, the case where the vibrations of the radiator support upper member 30 and the front side members 12A and 12B are in opposite phases in the vehicle front-rear direction has been described, but in the case of the same phase, the vehicle of the radiator support upper member 30 By configuring so as to suppress the vibration in the front-rear direction, the vibration of the front side members 12A and 12B can be suppressed.

  In the present embodiment, the cross-sectional shape of the radiator support upper member 30 at the mounting position of the V braces 16A and 16B is low in cross-sectional height, the front side is low in the vehicle front-rear direction, and the V brace mounting position (height) is Although it has been offset from the center of the cross section, any one or a combination of the two may be used.

  Furthermore, in the present embodiment, the cross-sectional shape and the V brace mounting position at the V brace mounting position in the radiator support upper member 30 are changed, but it is also possible to adjust only the shape of the beads 72A and 72B without performing this. In this case, by providing the beads 72A and 72B, the longitudinal deformation amount of the radiator support upper member 30 that causes torsional deformation can be adjusted, thereby suppressing the vehicle longitudinal vibration of the front side members 12A and 12B. .

  In the present embodiment, the beads 72A and 72B are concave portions formed in the upper surface 60 of the radiator support upper member 30, but may be convex portions.

  Further, in the present embodiment, the beads 72A and 72B are formed at the V brace mounting position in the vehicle width direction of the radiator support upper member 30, but the present invention is not limited to this. It may be somewhat shifted in the vehicle width direction. Including such a case, it is included in the “position corresponding to the brace fixing position” in the present invention.

10 Vehicle front structure 12A, 12B Front side member 16A, 16B V brace (brace)
26 Radiator support lower members 28A, 28B Radiator support side members 30 Radiator support upper members 72A, 72B Beads

Claims (1)

A pair of front side members extending in the vehicle front-rear direction at both ends in the vehicle width direction at the front of the vehicle;
A pair of left and right radiator support side members connected to the front end of each front side member and extending in the vehicle vertical direction;
Connecting the upper ends of the radiator support side members, and a radiator support upper member extending in the vehicle width direction;
Connecting the lower ends of the radiator support side members, and a radiator support lower member extending in the vehicle width direction;
A pair of left and right braces connecting the tip of each front side member and the radiator support upper member;
A bead formed on the upper surface of the radiator support upper member at a position corresponding to a fixed position of the brace of the radiator support upper member in the vehicle width direction and extending in the vehicle front-rear direction;
A vehicle front structure comprising:

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