JP5924033B2 - Lower body structure - Google Patents

Description

The present invention relates to a vehicle body lower structure, and more specifically, a dash panel disposed in a vehicle width direction at a front portion of a vehicle, a floor panel extending rearward from a rear portion of the dash panel, and a center portion of the floor panel And a tunnel member extending in the front-rear direction of the vehicle body along both sides of the floor tunnel in the vehicle width direction.

In general, the above-described floor tunnel structure is required to satisfy various requirements such as collision requirements, NVH requirements (NVH stands for noise noise, vibration vibration, harshness coupled vibration), layout requirements, and the like. Yes.
As means for satisfying such requirements, it is known to provide a reinforcing member in a floor tunnel (see Patent Documents 1 and 2).

The conventional structure disclosed in Patent Document 1 is a structure in which the left and right upper corners of the floor tunnel are reinforced with a reinforcing member from the lower side, that is, the vehicle outer side.
The conventional structure disclosed in Patent Document 2 is a structure in which a tunnel reinforcement (tunnel reinforcing member) having an upper and lower divided structure composed of an upper portion of a reinforcement and a lower portion of a reinforcement is disposed on the back side of the tunnel portion as a side collision corresponding structure. is there.

However, the conventional structure of any disclosed in Patent Documents 1 and 2 described above is also a structure for collision load capacity increase such as side collision, is not sufficient for the NVH characteristics, there is room for improvement.
The present inventors have, in order to improve the NVH characteristics, was examined the mechanism.
As a result, when the vehicle travels, stress concentrates on the upper corner of the tunnel reinforcing member, and the upper surface of the tunnel reinforcing member is deformed, so that the floor tunnel may fall sideways (vibration in the vehicle width direction). I found it.
That is, the floor tunnel has a resonance frequency that falls sideways, and when the input of this resonance frequency enters the floor tunnel, the sideways mode is excited and the floor tunnel falls sideways (the tunnel matchbox deformation causes the tunnel to be Deforms like a shape).

The floor tunnel is integrally or integrally coupled with the floor tunnel, and vibration when the floor tunnel falls down is transmitted to the floor panel, and the floor panel itself vibrates up and down by the transmitted vibration.
If there is air in the passenger compartment on the floor panel and the natural frequency of this air itself (about 160H _Z ) and the natural frequency of the floor tunnel lying down are at approximately the same resonance frequency, two resonances will occur. Overlapping frequencies creates a louder sound.
In other words, the lateral falling amplified vibrations in the floor tunnel is transmitted to the floor panel, vibration transmitted from the floor panel in the passenger compartment of the air is further amplified by the vibration mode of the air, unpleasant sound to the occupant (100～200H _Z muffled sound).
Therefore, the problem is how to suppress the floor tunnel sideways mode (specifically, deformation of the upper surface of the tunnel reinforcement member) during vehicle travel.

Japanese Patent Laid-Open No. 2005-199788 JP 2005-297610 A

  Therefore, the present invention suppresses deformation of the upper surface of the reinforcing member while maintaining the function of improving the collision safety performance inherent to the reinforcing member, and suppresses the sideways mode (vibration in the vehicle width direction) of the tunnel when the vehicle is running. Then, it aims at provision of the vehicle body lower part structure which can aim at the improvement of NVH performance.

The vehicle body lower structure according to the present invention includes a dash panel disposed in the vehicle width direction at the front of the vehicle, a floor panel extending rearward from the rear portion of the dash panel, and a center portion of the floor panel. A vehicle body lower structure comprising a floor tunnel that has been taken out and a tunnel member that extends in the vehicle longitudinal direction along both sides of the floor tunnel in the vehicle width direction. A reinforcing member that forms a closed cross-section with the surface of the floor tunnel on the lower side of the vehicle body from the tunnel member to the other tunnel member, and the surface of the reinforcing member that faces away from the surface of the floor tunnel on the lower side of the vehicle body An upper surface portion facing the upper portion of the floor tunnel in a front view of the vehicle body, a side surface portion facing the side portion of the floor tunnel, and the tunnel extending from the side surface portion in the vehicle width direction. A laterally extending portion connected to the member, an inclined portion facing the upper ends of the floor tunnel and connecting the upper surface portion and the side surface portion, a first bent portion connecting the upper surface portion and the inclined portion, and the inclined portion; A second bent portion connecting the side portion;
A third bent portion connecting the side surface portion and the laterally extending portion, W1 is a distance between the first bent portions on both sides, W2 is a distance between the third bent portions on both sides, and When the distance between the straight line connecting the third bent parts and the second bent part is H1, and the distance between the straight line connecting the third bent parts on both sides and the first bent part is H2, (W1 / W2 ) × (H1 / H2) is Ri der 0.12 or less, the above in the first bent portion in the vehicle width direction cross section of the surface facing apart from the vehicle body lower side surface of the floor tunnel of the reinforcing member The angle formed between the upper surface portion and the inclined portion and the angle formed between the inclined portion and the side surface portion in the second bent portion are set substantially equal .

According to the above configuration, (W1 / W2) × (H1 / H2) is set to 0.12 or less, so that deformation of the upper surface of the reinforcing member is suppressed while maintaining the originally improved collision safety performance function of the reinforcing member. Thus, the floor tunnel sideways mode (vibration in the vehicle width direction) during vehicle travel can be suppressed, and the NVH performance can be improved.
Specifically, it is possible to suppress the generation of unpleasant sounds such as pressing an occupant's ear (muffled sound frequency 100~200H _Z).

In addition , the angle formed by the upper surface portion and the inclined portion in the first bent portion in the cross section in the vehicle width direction of the surface facing the lower side of the vehicle body of the floor tunnel of the reinforcing member, what der what angle between the inclined portion and the side surface portion at the second bent portion is set to be substantially the same, and thus, the angle formed between the inclined portion and the upper surface portion of the first bending portion, the Since the angle formed between the inclined portion and the side portion at the two bent portions is set to be approximately equal, the floor tunnel sideways mode can be further suppressed.

In one embodiment of the present invention, a side sill extending along the vehicle longitudinal direction on both sides of the floor panel, and a cross member joined to the floor panel and extending in the vehicle width direction between the floor tunnel and the side sill. And the reinforcing member is disposed at a position that does not overlap the cross member in the longitudinal direction of the vehicle body.
According to the above configuration, the reinforcing member is disposed at a position where the vertical vibration of the floor panel is easily excited by the sideways mode of the floor tunnel, that is , the position where the floor panel is not restrained by the cross member. The vertical vibration suppression can be further effectively increased.

The vehicle body lower structure according to the present invention also includes a dash panel disposed in the vehicle width direction at the front of the vehicle, a floor panel extending rearward from the rear of the dash panel, and an upper portion at the center of the floor panel. And a tunnel member extending in the vehicle longitudinal direction along both sides in the vehicle width direction of the floor tunnel, the vehicle body lower structure comprising a floor tunnel lower surface of the floor tunnel. A reinforcing member that forms a closed cross section with the lower surface of the vehicle body of the floor tunnel extends from one tunnel member to the other tunnel member, and is spaced apart from the surface of the floor tunnel on the lower side of the vehicle body. The surface extends in the vehicle width direction from the upper surface portion facing the floor tunnel upper portion, the side surface portion facing the floor tunnel side portion, and the side surface portion in the vehicle body front view. A laterally extending portion connected to the tunnel member, an inclined portion that faces the upper ends of the floor tunnel and connects the upper surface portion and the side surface portion, a first bent portion that connects the upper surface portion and the inclined portion, and the inclined portion, A second bent portion that connects the side surface portion, and a third bent portion that connects the side surface portion and the laterally extending portion, and the distance between the first bent portions on both sides is W1, and The distance between the three bent portions is W2, the straight line connecting the third bent portions on both sides and the second bent portion is H1, the straight line connecting the third bent portions on both sides and the first bent portion (W1 / W2) × (H1 / H2) is 0.12 or less, the side sill extending along the longitudinal direction of the vehicle body on both sides of the floor panel, and joined to the floor panel It extends in the vehicle width direction between the floor tunnel and the side sill. And the reinforcing member is disposed at a position that does not overlap the cross member in the longitudinal direction of the vehicle body.

According to the above configuration, (W1 / W2) × (H1 / H2) is set to 0.12 or less, so that deformation of the upper surface of the reinforcing member is suppressed while maintaining the originally improved collision safety performance function of the reinforcing member. Thus, the floor tunnel sideways mode (vibration in the vehicle width direction) during vehicle travel can be suppressed, and the NVH performance can be improved.
Specifically, an unpleasant sound (frequency 100 to 200H) that squeezes the passenger's ear. _Z The generation of (sounding noise) can be suppressed.

In addition, the cross member includes a side sill extending along the vehicle longitudinal direction on both sides of the floor panel, and a cross member joined to the floor panel and extending in the vehicle width direction between the floor tunnel and the side sill. The above-mentioned reinforcing member is disposed at a position where it does not overlap in the front-rear direction, and the floor panel is in a position where vertical vibration of the floor panel is likely to be excited by the sideways mode of the floor tunnel, that is, the floor panel is not restrained by the cross member. Since the reinforcing member is disposed at the position, the vertical vibration suppression of the floor panel can be further effectively enhanced.

In one embodiment of the present invention, the dash panel includes a dash upper panel having both ends joined to the vehicle body, and a dash lower panel joined to a lower portion of the dash upper panel, and the dash upper panel in the vehicle front-rear direction. The reinforcing member is disposed between the panel and the cross member.
According to the above configuration, since the reinforcing member is disposed at a position where the vertical vibration of the floor panel is most likely to be excited by the sideways mode of the floor tunnel, that is , between the restraint portions of the vehicle body and the cross member, The vertical vibration suppression can be further effectively increased.

In one embodiment of the present invention, the reinforcing member is disposed in the approximate center between the dash upper panel and the cross member in the longitudinal direction of the vehicle body.
According to the above configuration, since the reinforcing member is provided in a portion that becomes an antinode of the floor tunnel sideways mode, that is, a portion where the amplitude of the vibration frequency is maximum, the tunnel sideways mode suppression effect is further enhanced. Can do.

In one embodiment of the present invention, the reinforcing member has a substantially cross-sectional shape in the longitudinal direction of the vehicle body, and the front end portion of the substantially hat-shaped longitudinal direction of the vehicle body is overlapped and joined together with the dash lower panel and the floor tunnel. It is a thing.
According to the above configuration, since the reinforcement member is overlapped and joined to the portion where the dash lower panel and the floor tunnel are joined and the body rigidity is originally high, the rigidity of the reinforcement member itself is further increased, and the reinforcement member It is possible to suppress the deformation of the upper surface portion.
Therefore, it is possible to further suppress the floor tunnel sideways mode when the vehicle travels, and to further improve the NVH performance.

  According to the present invention, the deformation of the upper surface of the reinforcing member is suppressed while maintaining the function of improving the collision safety performance that the reinforcing member originally has, and the sideways mode of the tunnel (vibration in the vehicle width direction) during vehicle travel is suppressed. As a result, the NVH performance can be improved.

The top view which shows the Example of the vehicle body lower part structure of this invention Bottom view showing the undercarriage structure Side view showing the underbody structure Partial expanded sectional view which follows the AA line of FIG. BB cross-sectional view of FIG. Perspective view of reinforcing member Cross section of reinforcing member A perspective view of a simplified model of a reinforcing member used to verify the effect Characteristic diagram showing verification results Explanatory diagram showing verification results

While maintaining the collision safety performance improving function inherent to the reinforcing member, the deformation of the upper surface of the reinforcing member is suppressed, and the sideways mode of the tunnel (vibration in the vehicle width direction) when the vehicle is running is suppressed. For the purpose of improving, a dash panel arranged in the vehicle width direction at the front part of the vehicle, a floor panel extending rearward from the rear part of the dash panel, and a bulge upward at the center part of the floor panel And a tunnel member extending in the longitudinal direction of the vehicle body along both sides of the floor tunnel in the vehicle width direction, from one tunnel member along the lower surface of the vehicle body of the floor tunnel. A reinforcing member that forms a closed cross-section along with the lower surface of the vehicle body of the floor tunnel across the other tunnel member; The surface facing away from the side surface includes an upper surface portion facing the floor tunnel upper portion in a front view of the vehicle body, a side surface portion facing the floor tunnel side portion, and extending from the side surface portion in the vehicle width direction to the tunnel member. A laterally extending portion that is connected, an inclined portion that faces both ends of the upper portion of the floor tunnel and connects the upper surface portion and the side surface portion, a first bent portion that connects the upper surface portion and the inclined portion, the inclined portion, and the side surface And a third bent portion connecting the side surface portion and the laterally extending portion, and the distance between the first bent portions on both sides is W1, and the third bent portions on both sides W2 is the distance between the parts, H1 is the distance between the straight line connecting the third bent parts on both sides and the second bent part, and the distance between the straight line connecting the third bent parts on both sides and the first bent part when was the H2, the (W1 / W2) × (H1 / H2) and 0.12 or less An angle formed by the upper surface portion and the inclined portion in the first bent portion in a cross section in the vehicle width direction of a surface facing away from the vehicle body lower side surface of the floor tunnel of the reinforcing member, and the second This is realized by a configuration in which the angle formed by the inclined portion and the side surface portion at the bent portion is set to be approximately equal .

An embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a plan view of the lower body structure, FIG. 2 is a bottom view of the lower body structure, and FIG. 3 is a side view of the vehicle body vertically cut at the center in the vehicle width direction.

1 to 3, a dash panel 1 disposed in the vehicle width direction is provided at the front of the vehicle. The dash panel 1 includes a dash upper panel 3 whose left and right ends are joined to a hinge pillar 2 as a vehicle body, and a dash lower panel 4 joined to the lower portion of the dash upper panel 3.
The dash lower panel 4 described above is a panel member that partitions the engine room and the vehicle compartment in the front-rear direction, and a tunnel portion 5 that bulges upward is integrally formed at the center of the dash lower panel 4 in the vehicle width direction. This tunnel portion 5 is integrated with a tunnel portion 14 of a floor panel 13 described later.
Further, a dash cross member 6 having a substantially hat-shaped cross section is joined and fixed to the front portion of the above-described dash lower panel 4 at an intermediate position in the vertical direction, and between the dash cross member 6 and the dash lower panel 4 in the vehicle width direction. A dash cross closed section 7 extending in the direction is formed to improve the rigidity of the dash panel 1.
As shown in FIG. 1, the hinge pillar 2 described above is a vehicle body rigid member in which a hinge pillar inner 2a and a hinge pillar outer 2b are joined and fixed to form a hinge pillar closed section 2c extending in the vertical direction. The front door (not shown) is attached to be openable and closable.

  As shown in FIG. 3, the rear end lower portion of the cowl panel 8 is connected to the upper surface of the rear end portion of the above-described dash upper panel 3, and the upper surface of the connecting portion between the dash upper panel 3 and the dash lower panel 4 is A cowl front rain 11 is attached to the front part of the cowl front 9 so as to form a closed cross-section 10 between the cowl front 9 having a concave cross section and fixed to the back of the front vertical wall 9a of the cowl front 9. By joining, the cowl part 12 of the open cowl structure which consists of said each element 3,8,9,11 is comprised.

As shown in FIGS. 1 and 2, a floor panel 13 extending substantially horizontally from the rear end of the lower end of the dash lower panel 4 to the rear is provided, and the floor panel 13 has a central portion in the vehicle width direction. It is provided with a tunnel portion 14 of the floor tunnel that bulges upward. The tunnel portion 14 is integrated with the tunnel portion 5 formed by the dash lower panel 4 so as to be continuous in the longitudinal direction of the vehicle body.
The floor panel 13 described above constitutes the bottom surface (floor surface) of the passenger compartment. As shown in FIGS. 1 and 2, side sills 15 and 15 extending along the longitudinal direction of the vehicle body are provided on the left and right sides of the floor panel 13. Provided. The side sill 15 is a vehicle body strength member having a side sill closed cross section extending in the vehicle longitudinal direction by joining and fixing the joint flange portion between the side sill inner 15a and the side sill outer 15b.

1, a pair of left and right cross members 16, which are joined to the floor panel 13 and extend in the vehicle width direction between the side wall of the tunnel portion 14 and the vertical wall of the side sill inner 15a in the side sill 15, 16 (so-called No. 2 cross member) is provided.
These left and right cross members 16 and 16 (No. 2 cross member) are arranged in a straight line in the vehicle width direction with the tunnel portion 14 therebetween, and the vehicle width is between the cross member 16 and the floor panel 13. A closed cross section extending in the direction is formed.

Further, a pair of left and right members that are joined to the floor panel 13 and extend in the vehicle width direction between the side wall of the tunnel portion 14 and the vertical wall of the side sill inner 15a in the side sill 15 also at a position separated from the cross member 16 and the rear of the vehicle body. Cross members 17 and 17 (so-called No. 2.5 cross members) are provided.
These left and right cross members 17 and 17 (No. 2.5 cross member) are also No. Like the two cross members, they are arranged in a straight line in the vehicle width direction across the tunnel portion 14, and a closed cross section extending in the vehicle width direction is formed between the cross member 17 and the floor panel 13. Yes.

  Here, instead of the left and right split type cross members 16 and 17 described above, a cross member having a left and right non-split structure in which the left and right cross member portions are integrated with a panel member straddling the tunnel portion 14 may be adopted. Of course.

As shown in FIG. 1, the front cross member 16 (No. 2 cross member) is disposed corresponding to an intermediate portion in the vehicle body front-rear direction between the hinge pillar 2 and the center pillar 18, and the rear cross member 16 The member 17 (No. 2.5 cross member) is disposed at a position where a part thereof overlaps the front portion of the center pillar 18 in the longitudinal direction of the vehicle body.
The above-described center pillar 18 is a vehicle body strength member having a center pillar closed section 18c extending in the vertical direction of the vehicle body by joining and fixing the center pillar inner 18a and the center pillar outer 18b.

On the other hand, as shown in a bottom view in FIG. 2, a rear cross member 19 (so-called No. 3 cross member) extending in the vehicle width direction is further rearward of the rear cross member 17 (No. 2.5 cross member). Is provided.
The rear cross member 19 is a vehicle body strength member having a closed cross-sectional structure that is laid between the front end portions of the left and right rear side frames 20 and 20, and the pair of left and right rear side frames 20 and 20 described above is a lower surface of a rear floor (not shown). The side surfaces of the front end portions of the rear side frame 20 are connected to the rear end portions of the side sill inners 15a and 15a of the left and right side sills 15 and 15, respectively.
Further, as shown in FIG. 2, in correspondence with the arrangement position of the front cross members 16 and 16 (No. 2 cross member), the side of the outer side of the tunnel portion 14 , that is , the lower side of the vehicle body, The reinforcing member 21 corresponding to the collision is joined and fixed to improve the side collision resistance.

Similarly, as shown in FIG. 2, the outer side surface of the tunnel portion 14 , that is , the lower surface of the vehicle body , corresponding to the arrangement position of the rear cross members 17, 17 (No. 2.5 cross member). In addition, the side impact resistant reinforcement member 22 is joined and fixed to improve the side impact resistance.

  4 is a cross-sectional view taken along the line AA in FIG. 2, and FIG. 5 is a cross-sectional view taken along the line BB in FIG. 3. As shown in FIGS. A pair of left and right tunnel members 23, 23 extending in the longitudinal direction of the vehicle body are provided.

  As shown in FIG. 5, the tunnel member 23 described above has a hat-shaped cross section. In this embodiment, the tunnel member 23 is joined to the lower surface of the floor panel 13 along the lower edge of the tunnel portion 14. A closed cross section 24 extending in the longitudinal direction of the vehicle body is formed between the floor panel 13 and the tunnel member 23.

  As shown in FIG. 5, in this embodiment, the floor panel 13, the tunnel portion 14, and the tunnel member 23 are configured by separate members, and the lower end portion of the tunnel portion 14 is a vehicle of the floor panel 13. Although sandwiched between the inner end in the width direction and the inner end in the vehicle width direction of the tunnel member 23, a structure in which the floor panel and the tunnel portion are integrally formed is adopted instead of this structure. Alternatively, a structure in which a tunnel portion and a tunnel member are integrally formed may be employed.

  As shown in FIG. 2, a floor frame 25 is provided at an intermediate portion in the vehicle width direction between the tunnel member 23 and the side sill 5 described above. The pair of left and right floor frames 25 have a hat-shaped cross section. By fixing the floor frame 25 to the lower surface of the floor panel 13, the floor frame 25 is interposed between the floor panel 13 and the floor frame 25. A closed cross section extending in the longitudinal direction of the vehicle body is formed.

As shown in FIG. 2, a pair of left and right front side frames 26, 26 are provided so as to be continuous with the above-described floor frame 25 in the longitudinal direction of the vehicle body. The front side frame 26 is a vehicle body strength member that extends in the longitudinal direction of the vehicle body. A front portion of the front side frame 26 extends from the dash lower panel 4 to the front of the vehicle body on both sides of the engine room, and a rear portion of the front side frame 26 extends from the lower surface of the dash lower panel 4 to the floor panel. As shown in FIG. 2, the front side frame 26, the floor frame 25, and the rear side frame 20 are configured to be continuous in the longitudinal direction of the vehicle body.
In FIG. 2, 27 is a suspension tower section, 28 is an apron reinforcement, and an arrow F indicates the front of the vehicle.

  As shown in FIGS. 2 to 5, a closed cross section 29 is formed along with the surface of the tunnel portion 14 on the vehicle body lower side from one tunnel member 23 to the other tunnel member 23 along the surface of the tunnel portion 14 on the vehicle body lower side. A tunnel gusset 30 is provided as a reinforcing member.

  FIG. 6 is a perspective view of the tunnel gusset 30 alone. The tunnel gusset 30 includes a pair of front and rear joining flange portions 31 and 32 along the surface of the tunnel portion 14 on the vehicle body lower side, and the front and rear joining flange portions 31 and 32. A gusset body 33 positioned between the gusset body 33, a vertical wall 34 connecting the front end of the gusset body 33 and the front joint flange 31, and a rear end and rear joint flange 32 of the gusset body 33. The vertical wall part 35 which connects between is formed integrally, and is comprised by the substantially bowl shape as a whole.

As shown in FIG. 2 and FIG. It is set at a position that does not overlap the cross member 16 as a two cross member.
Specifically, as shown in FIG. 3, the tunnel gusset 30 is disposed between the dash upper panel 3 and the cross member 16 in the longitudinal direction of the vehicle body. More specifically, the dash upper is defined in the longitudinal direction of the vehicle body. A tunnel gusset 30 is disposed in the approximate center in the vehicle longitudinal direction between the panel 3 and the cross member 16. That is, the tunnel gusset 30 is provided at a place where the floor panel 13 is not restrained by the strength member and where the vertical vibration of the floor panel 13 is easily excited.

As shown in FIG. 4, the above-described tunnel gusset 30 has a cross section in the longitudinal direction of the vehicle body formed in a substantially hat shape, and a front end portion of the substantially hat shape in the longitudinal direction of the vehicle body, that is, a joint flange portion 31 on the front side is a dash lower panel. 4 and the front end portion of the tunnel portion 14 are overlapped and joined together.
That is, the above-described joining flange portion 31 is sandwiched and joined between the dash lower panel 4 and the tunnel portion 14 as shown in FIG.
Also, the joint flange portion 32 on the rear side of the tunnel gusset 30 is joined to the surface of the tunnel portion 14 on the vehicle body lower side, and the above-described closed section 29 is formed between the tunnel portion 14 and the gusset body 33. .

  As shown in FIG. 5, the surface facing the lower side of the vehicle body of the tunnel portion 14 of the tunnel gusset 30 described above, that is, the gusset body 33 is an upper surface facing the upper portion of the tunnel portion 14 in a front view of the vehicle body. Part 33A, side part 33B facing the side part of tunnel part 14, side extension part 33C extending outward in the vehicle width direction from the lower end of side part 33B and connected to tunnel member 23 by spot welding, tunnel part 14, an inclined portion 33D that faces the upper ends of the upper surface 33A and connects the upper surface portion 33A and the side surface portion 33B, a first bent portion K1 that connects the upper surface portion 33A and the inclined portion 33D, and the inclined portion 33D described above. It has the 2nd bending part K2 which connects the side part 33B, and the 3rd bending part K3 which connects the above-mentioned side part 33B and the side extension part 33C.

5 and 7, the distance between the first bent portions K1 and K1 on both the left and right sides is W1, the distance between the third bent portions K3 and K3 on the left and right sides is W2, and the third bent on the left and right sides is the same. The vertical distance between the straight line L connecting the parts K3 and K3 and the second bent part K2 is H1, and the vertical line between the straight line L connecting the third bent parts K3 and K3 on the left and right sides and the first bent part K1 is When the distance is H2,
(W1 / W2) × (H1 / H2) is set to 0.12 or less.

The reason why this (W1 / W2) × (H1 / H2) is 0.12 or less will be verified based on the experimental results described later.
Further, as shown in FIG. 7, the surface of the tunnel gusset 30 that faces away from the lower surface of the vehicle body of the tunnel portion 14, that is, the upper surface portion at the first bent portion K <b> 1 in the cross section in the vehicle width direction of the gusset body 33. The angle θ1 formed by 33A and the inclined portion 33D and the angle θ2 formed by the inclined portion 33D and the side surface portion 33B at the second bent portion K2 are set substantially equal.

  In FIG. 7, when the intersection of the virtual extension line of the upper surface portion 33A and the virtual extension line of the side surface portion 33B is P, a triangle surrounded by the intersection point P, the first bent portion K1, and the second bent portion K2 is formed. When the angles θ1 and θ2 are substantially equal, and the triangle is an isosceles triangle, the side-down mode is effectively suppressed.

If the areas of the triangles are the same, a triangle between P and K1 larger than between P and K2 is assumed. However, in this case, θ1 <θ2 and the angle θ1 becomes too small. On the contrary, a triangle with a smaller distance between P and K1 than between P and K2 is also assumed, but in this case, θ1> θ2 and the angle θ2 becomes too small, which is not preferable.
For this reason, it is preferable that both angles θ1, θ2 are substantially equal and the triangle surrounded by P, K1, K2 is formed into an isosceles triangle.

FIG. 8 is a perspective view showing a simplified model M of the tunnel gusset 30 used for verifying the effect. As this simplified model M, the left and right laterally extending portions 33C, 33C from the tunnel gusset 30 shown in FIGS. The one without 33C is used.
Then, four points R1, R2, R3, and R4 before and after the third bent portion K3 of the simple model M are constrained, and vibration is applied to the simple model M from the lateral direction indicated by an arrow in FIG. The change in the resonance frequency was determined using the middle in the front-rear direction of K1 as the excitation / response point.

  FIG. 9 is a characteristic diagram showing the verification results. The horizontal axis represents the value of (W1 / W2) × (H1 / H2), and the vertical axis represents the resonance frequency of the simple model M actually measured. However, the distance W2 and the height H2 are constant when obtaining the verification result.

  Further, FIG. 10 shows a value obtained by actually measuring the lateral fall resonance frequency by changing the value of (W1 / W2) × (H1 / H2), the distance W1, and the height H1 of the simple model M shown in FIG. It is explanatory drawing which shows the result of having calculated the increase of the side-down resonance frequency when using the leftmost thing in FIG. 10 as a reference | standard, and the result of having verified the presence or absence of a deformation | transformation of the upper surface part 33A.

As is clear from the characteristic diagram of FIG. 9, the larger the value of (W1 / W2) × (H1 / H2) (in other words, the area of the triangle surrounded by the points K1, K2, and P shown in FIG. 7). The smaller the value of (W1 / W2) × (H1 / H2) (in other words, the area of the triangle surrounded by the points K1, K2, and P shown in FIG. 7). 10), the resonance frequency increases, and the resonance frequency increases rapidly when the value of (W1 / W2) × (H1 / H2) is 0.12 or less with 0.12 as a boundary. As shown in the explanatory diagram, when (W1 / W2) × (H1 / H2) is 0.12 or less, it was recognized that the upper surface portion 33A was not deformed.
That is, when (W1 / W2) × (H1 / H2) is 0.12 or less, the resonance frequency becomes high, and the natural frequency of air and the natural falling frequency of the tunnel fall apart greatly, whereby the upper surface portion 33A. It was confirmed that there was no deformation.

  As described above, the vehicle body lower structure of the above embodiment includes the dash panel 1 disposed in the vehicle width direction at the front portion of the vehicle, the floor panel 13 extending rearward from the rear portion of the dash panel 1, and the floor. A vehicle body lower structure comprising a tunnel portion 14 bulging upward at the center of the panel 13 and a tunnel member 23 extending in the vehicle longitudinal direction along both sides of the tunnel portion 14 in the vehicle width direction. A reinforcing member (see tunnel gusset 30) that forms a closed cross-section 29 with the surface of the tunnel portion 14 on the vehicle body lower side from one tunnel member 23 to the other tunnel member 23 along the surface of the portion 14 on the vehicle body lower side. The surface of the reinforcing member (tunnel gusset 30) facing the lower side of the vehicle body of the tunnel portion 14 (see the gusset body 33) is a front view of the vehicle body. An upper surface portion 33A facing the upper portion of the tunnel portion 14, a side surface portion 33B facing the side portion of the tunnel portion 14, a side extending portion 33C extending from the side surface portion 33B in the vehicle width direction and connected to the tunnel member 23, a tunnel An inclined portion 33D that faces the upper ends of the portion 14 and connects the upper surface portion 33A and the side surface portion 33B; a first bent portion K1 that connects the upper surface portion 33A and the inclined portion 33D; and the inclined portion 33D. A second bent portion K2 that connects the side surface portion 33B; and a third bent portion K3 that connects the side surface portion 33B and the laterally extending portion 33C; and between the first bent portions K1 and K1 on both sides. The distance is W1, the distance between the third bent portions K3 and K3 on both sides is W2, the distance between the straight line L connecting the third bent portions K3 and K3 on both sides and the second bent portion K2 is H1, and the both sides 3rd bent part K3 of (W1 / W2) × (H1 / H2) is 0.12 or less when the distance between the straight line L connecting the three and the first bent portion K1 is H2 (see FIG. 3, see FIG.

According to this configuration, since (W1 / W2) × (H1 / H2) is set to 0.12 or less, the reinforcing member (refer to the tunnel gusset 30) maintains the originally improved collision safety performance function while the reinforcing member ( The deformation of the upper surface portion 33A of the tunnel gusset 30) can be suppressed, the sideways mode (vibration in the vehicle width direction) of the tunnel portion 14 during vehicle travel can be suppressed, and the NVH performance can be improved. .
Specifically, it is possible to suppress the generation of unpleasant sounds such as pressing an occupant's ear (muffled sound frequency 100~200H _Z).
In addition, the upper surface of the reinforcing member (tunnel gusset 30) at the first bent portion K1 in the cross section in the vehicle width direction of the surface (see the gusset body 33) that faces away from the surface of the tunnel portion 14 on the vehicle body lower side. The angle θ1 formed by the portion 33A and the inclined portion 33D and the angle θ2 formed by the inclined portion 33D and the side surface portion 33B at the second bent portion K2 are set substantially equal (see FIG. 7). .

According to this configuration, the angle θ1 formed between the upper surface portion 33A and the inclined portion 33D at the first bent portion K1 and the angle θ2 formed between the inclined portion 33D and the side surface portion 33B at the second bent portion K2 are set substantially equal. As a result, the sideways mode of the tunnel portion 14 can be further suppressed.
Further, a side sill 15 extending along the longitudinal direction of the vehicle body on both sides of the floor panel 13 and a cross member 16 joined to the floor panel 13 and extending in the vehicle width direction between the tunnel portion 14 and the side sill 15 are provided. The reinforcing member (see the tunnel gusset 30) is disposed at a position where it does not overlap the cross member 16 in the longitudinal direction of the vehicle body (see FIG. 2).

According to this configuration, the reinforcing member (tunnel gut 30) is placed at a position where the vertical vibration of the floor panel 13 is easily excited by the sideways mode of the tunnel portion 14, that is, the position where the floor panel 13 is not restrained by the cross member 16. Since it has been arranged, the vertical vibration suppression of the floor panel 13 can be further effectively enhanced.
In addition, the dash panel 1 includes a dash upper panel 3 whose both ends are joined to the vehicle body (see the hinge pillar 2), and a dash lower panel 4 joined to the lower portion of the dash upper panel 3 in the vehicle longitudinal direction. The reinforcing member (see the tunnel gusset 30) is disposed between the dash upper panel 3 and the cross member 16 (see FIG. 3).

According to this configuration, the reinforcing member (tunnel gusset 30) is placed between the position where the vertical vibration of the floor panel 13 is most likely to be excited by the sideways mode of the tunnel portion 14, that is, between the restrained portions of the vehicle body and the cross member 16. Due to the arrangement, the vertical vibration suppression of the floor panel 13 can be further effectively enhanced.
Further, the reinforcing member (refer to the tunnel gusset 30) is disposed at the approximate center between the dash upper panel 3 and the cross member 16 in the longitudinal direction of the vehicle body (see FIG. 3).

According to this configuration, since the reinforcing member (tunnel gusset 30) is provided at the portion of the tunnel portion 14 that becomes the antinode of the sideways fall mode, that is, the portion where the amplitude of the vibration frequency is maximized, the tunnel sideways mode is suppressed. The effect can be further enhanced.
Further, the reinforcing member (refer to the tunnel gusset 30) has a substantially hat-shaped cross section in the longitudinal direction of the vehicle body, and the front end portion of the substantially hat-shaped longitudinal direction of the vehicle body (refer to the front flange portion 31) is connected to the dash lower panel 4. And the above-described tunnel portion 14 and overlap-joined (see FIG. 4).

According to this configuration, since the reinforcing member (tunnel gusset 30) is overlapped and joined to a portion where the dash lower panel 4 and the tunnel portion 14 are joined and the body rigidity is originally high, the reinforcing member (tunnel gusset 30) is joined. As a result, the rigidity of the reinforcing member (tunnel gusset 30) can be prevented from being deformed.
Therefore, it is possible to further suppress the sideways mode of the tunnel portion 14 when the vehicle travels, and to further improve the NVH performance.

In the correspondence between the configuration of the present invention and the above-described embodiment,
The floor tunnel of the present invention corresponds to the tunnel portion 14 of the above-described embodiment,
Similarly,
The reinforcing member corresponds to the tunnel gusset 30,
The closed section corresponds to the closed section 29,
The car body corresponds to the hinge pillar 2,
The present invention is not limited to the configuration of the above-described embodiment.

  For example, no. 2.5 In the vehicle body lower structure not provided with the cross member 17 and the reinforcing member 22, No. 2 shown in FIG. 2 cross member 16 and No. 2 The tunnel gusset 30 may be arranged on the surface of the tunnel portion 14 on the vehicle body lower side corresponding to the intermediate portion of the three cross members 19 in the vehicle longitudinal direction.

  As described above, the present invention includes a dash panel disposed in the vehicle width direction at the front of the vehicle, a floor panel extending rearward from the rear of the dash panel, and an upper portion at the center of the floor panel. It is useful for a vehicle body lower structure provided with a floor tunnel that bulges out and a tunnel member that extends in the vehicle longitudinal direction along both sides of the floor tunnel in the vehicle width direction.

1 ... Dash panel 2 ... Hinge pillar (vehicle body)
3 ... Dash upper panel 4 ... Dash lower panel 13 ... Floor panel 14 ... Tunnel (floor tunnel)
15 ... side sill 16 ... cross member 23 ... tunnel member 29 ... closed section (closed section)
30 ... Tunnel gusset (reinforcing member)
33A ... Upper surface portion 33B ... Side surface portion 33C ... Side extension portion 33D ... Inclined portion K1 ... First bent portion K2 ... Second bent portion K3 ... Third bent portion

Claims (6)

A dash panel arranged in the vehicle width direction at the front of the vehicle;
A floor panel extending rearward from the rear of the dash panel;
A floor tunnel bulging upward at the center of the floor panel;
A vehicle body lower structure comprising a tunnel member extending in the longitudinal direction of the vehicle body along both sides of the floor tunnel in the vehicle width direction,
A reinforcing member that forms a closed cross-section along with the lower surface of the vehicle body of the floor tunnel from one tunnel member to the other tunnel member along the lower surface of the vehicle body of the floor tunnel,
The surface of the reinforcing member that faces away from the lower surface of the vehicle body of the floor tunnel is
An upper surface portion facing the upper portion of the floor tunnel in a front view of the vehicle body,
A side surface facing the floor tunnel side,
A laterally extending portion extending in a vehicle width direction from the side surface portion and connected to the tunnel member;
An inclined portion facing the upper ends of the floor tunnel and connecting the upper surface portion and the side surface portion;
A first bent portion connecting the upper surface portion and the inclined portion;
A second bent portion connecting the inclined portion and the side surface portion;
A third bent portion connecting the side surface portion and the laterally extending portion;
Have
The distance between the first bends on both sides is W1, the distance between the third bends on both sides is W2, the distance between the straight line connecting the third bends on both sides and the second bend is H1, When the distance between the straight line connecting the third bent portions on both sides and the first bent portion is H2,
(W1 / W2) × (H1 / H2) is Ri der 0.12 or less,
An angle formed by the upper surface portion and the inclined portion at the first bent portion in a cross section in the vehicle width direction of a surface facing away from the lower surface of the vehicle body of the floor tunnel of the reinforcing member;
The vehicle body lower structure , wherein an angle formed between the inclined portion and the side surface portion in the second bent portion is set to be substantially equal . Side sills extending along the vehicle longitudinal direction on both sides of the floor panel;
A cross member joined to the floor panel and extending in the vehicle width direction between the floor tunnel and the side sill;
The vehicle body lower part structure according to claim 1, wherein the reinforcing member is disposed at a position that does not overlap the cross member in the vehicle longitudinal direction . A dash panel arranged in the vehicle width direction at the front of the vehicle;
A floor panel extending rearward from the rear of the dash panel;
A floor tunnel bulging upward at the center of the floor panel;
A vehicle body lower structure comprising a tunnel member extending in the longitudinal direction of the vehicle body along both sides of the floor tunnel in the vehicle width direction,
A reinforcing member that forms a closed cross-section along with the lower surface of the vehicle body of the floor tunnel from one tunnel member to the other tunnel member along the lower surface of the vehicle body of the floor tunnel,
The surface of the reinforcing member that faces away from the lower surface of the vehicle body of the floor tunnel is
An upper surface portion facing the upper portion of the floor tunnel in a front view of the vehicle body,
A side surface facing the floor tunnel side,
A laterally extending portion extending in a vehicle width direction from the side surface portion and connected to the tunnel member;
An inclined portion facing the upper ends of the floor tunnel and connecting the upper surface portion and the side surface portion;
A first bent portion connecting the upper surface portion and the inclined portion;
A second bent portion connecting the inclined portion and the side surface portion;
A third bent portion connecting the side surface portion and the laterally extending portion;
Have
The distance between the first bends on both sides is W1, the distance between the third bends on both sides is W2, the distance between the straight line connecting the third bends on both sides and the second bend is H1, When the distance between the straight line connecting the third bent portions on both sides and the first bent portion is H2,
(W1 / W2) × (H1 / H2) is 0.12 or less,
Side sills extending along the vehicle longitudinal direction on both sides of the floor panel;
A cross member joined to the floor panel and extending in the vehicle width direction between the floor tunnel and the side sill;
Characterized in that the reinforcing member is disposed at a position not overlapping with the cross member and the longitudinal direction of the vehicle body
Lower body structure. The dash panel includes a dash upper panel having both ends joined to the vehicle body, and a dash lower panel joined to a lower portion of the dash upper panel,
The vehicle body lower structure according to claim 2 or 3, wherein the reinforcing member is disposed between the dash upper panel and the cross member in a vehicle longitudinal direction. The vehicle body lower part structure according to claim 4 , wherein the reinforcing member is disposed substantially at the center between the dash upper panel and the cross member in the vehicle longitudinal direction. The reinforcing member is formed in a substantially hat shape in a cross section in the longitudinal direction of the vehicle body,
The vehicle body lower structure according to claim 4 or 5 , wherein a front end portion of the substantially hat-shaped body in the longitudinal direction is overlapped and joined together with the dash lower panel and the floor tunnel.

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