JP2006205871A - Floor panel structure of car body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a floor panel structure of a car body capable of effectively reducing the vibrational energy of a floor panel and reducing acoustic radiation from the floor panel. <P>SOLUTION: This floor panel structure of the car body constitutes a floor of an automobile by the floor panels 2, 6, 12 connected to a plurality of frame materials 22, 24, 27 to 32, etc. arranged in the car body longitudinal direction and in the car width direction, panel regions S1 to S4, S7, S8, S10 at least a part of which is surrounded by the frame members are formed in the floor panel, and in the panel regions of the floor panels, a high rigidity part 84 where the panel is projected upward or downward is formed on a central part of the panel regions, a low rigidity part 86 is formed around this high rigidity part, a damping material 88 is provided roughly in all of the region of the low rigidity part, and a cut out part 88c extending along the frame member at a position separated from the frame member is formed on this damping material. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a floor panel structure of a vehicle body, and more particularly to a floor panel structure of a vehicle body that forms a floor of an automobile by floor panels connected to a plurality of frame members arranged in a vehicle body longitudinal direction and a vehicle width direction. .

  It is known that vibration from a frame member to which an engine and a suspension are connected is transmitted to a floor panel, and this floor panel vibrates, resulting in unpleasant vehicle interior vibration and noise. In this case, vibrations of the engine itself and road noise transmitted from the suspension become a problem as the vibration source. This road noise is generally caused by tire cavity resonance and suspension resonance. Such unpleasant vibration transmitted from the engine or suspension is mainly 400 Hz or less in an automobile, and has a peak at a frequency around 250 Hz, which is road noise caused by tire cavity resonance.

Conventionally, in order to suppress these vibration noises, a vibration damping material and a vibration proof material are generally pasted on the floor panel and various parts of the vehicle body in the vicinity thereof as various vibration proof and sound proof measures.
It is also known to increase the rigidity by forming a large number of beads on the floor panel or increasing the panel thickness, thereby shifting the natural frequency of the floor panel to a high band higher than 400 Hz. That is, the floor panel does not resonate at the resonance frequency of the suspension, the cavity resonance frequency band of the tire, or the like, thereby reducing unpleasant vibration noise.
Moreover, in the vehicle body panel structure described in Patent Document 1, a plurality of shell structure convex portions that are resistant to bending, compression, and tension are formed on the panel, and concave portions extending vertically and horizontally between the convex portions. The vibration is damped by concentrating the vibration and providing a damping material in the recess.

JP-A-6-107235

However, the technology of attaching damping materials and vibration-proofing materials to the floor panel and nearby vehicle parts can reduce vibration and noise, but on the other hand, a very large amount of damping materials and vibration-proofing materials are required. Therefore, the weight of the vehicle is increased, thereby causing various problems in terms of various adverse effects and costs.
In addition, the technology of forming a large number of beads on the floor panel and increasing the panel thickness has the advantage of suppressing the resonance peak in the low frequency region, but on the other hand, the vibration in the high frequency region increases on the contrary. This requires a lot of damping materials and anti-vibration materials to suppress vibration noise in the vehicle, which increases the weight of the vehicle, thereby causing various adverse effects and costs, and it is desired to solve this problem. It was.
In the technique of Patent Document 1, vibration and noise can be reduced. However, by simply providing a damping material in the concave portions of the plurality of convex portions, it is possible to further suppress recent vibration noise and reduce the weight of the vehicle. There was a case where the vibration reduction effect sufficient to meet the demand could not be obtained.

  Therefore, the present invention has been made to solve the above-described problems of the prior art, effectively reducing vibration energy of the floor panel due to vibration transmitted from the frame member of the vehicle body, and reducing the sound from the floor panel. It aims at providing the floor panel structure of the vehicle body which can reduce radiation.

In order to achieve the above object, the present invention provides a floor panel structure of a vehicle body that constitutes a floor of an automobile by floor panels connected to a plurality of frame members arranged in a vehicle body longitudinal direction and a vehicle width direction. The floor panel is formed with a panel region that is at least partially surrounded by a frame member, and the panel region of the floor panel protrudes upward or downward at the center of the panel region. A high-rigidity portion is formed and a low-rigidity portion is formed around the high-rigidity portion. A vibration-damping material is provided in the low-rigidity portion, and the vibration-damping material is attached to the frame member at a position separated from the frame member. A cutout portion extending along the line is formed.
In the present invention configured as described above, in the panel region of the floor panel, a high-rigidity portion that protrudes upward or downward is formed at the center of the panel region, and the high-rigidity portion is formed. Since the low-rigidity portion is formed around the portion, vibration energy concentrates on the low-rigidity portion due to the difference in rigidity between the high-rigidity portion and the low-rigidity portion, and the vibration distortion of the low-rigidity portion increases. And since the damping material is provided in the low-rigidity part, the damping material is distorted along with the distortion of the low-rigidity part, and the vibration energy concentrated on the low-rigidity part is converted into thermal energy, and Vibration energy is reduced. Therefore, vibration can be effectively reduced by the vibration damping material provided in the low rigidity portion as described above, and as a result, acoustic radiation from the floor panel can be reduced and the weight of the vibration damping material can be reduced. I can do it.
Heretofore, it has been conventionally considered that the larger the area of the damping material provided in the panel region, the greater the vibration damping effect of the damping material. However, the inventors do not concentrate vibration energy along the frame member at a position separated from the frame member in the low rigidity portion formed around the high rigidity portion formed in the center portion of the panel region. In addition to finding that there is a region where the vibration distortion is small, and if a damping material is also provided in such a region where the vibration distortion is small, the vibration damping material will not be distorted. It has been found that the damping material in a region where the distortion is large is made difficult to distort, and the vibration energy reducing effect by the damping material is reduced. Therefore, according to the present invention, the vibration damping material is formed with a cutout portion extending along the frame member at a position separated from the frame member, so that vibration energy corresponding to the region where the cutout portion is formed has a vibration energy. As described above, it is possible to prevent the distortion in the region having a large vibration distortion from being suppressed by preventing the vibration damping material from being provided in the region where the vibration distortion is not concentrated. As a result, vibration energy can be more effectively reduced. Furthermore, the weight of the damping material is reduced by forming the cutout portion.

In the present invention, preferably, the frame member extends linearly, and the cutout portion extends parallel to the frame member.
In the present invention configured as described above, the frame member extends linearly, and the cutout portion extends parallel to the frame member extending linearly. Here, if the present inventors form the frame member so as to extend linearly, a region where the vibration energy is not concentrated and the distortion of vibration is reduced is generated so as to extend parallel to the frame member. I found. Therefore, according to the present invention, the cutout portion extends in parallel with the frame member extending in a straight line shape, so that the effect of reducing the vibration energy described above can be obtained more reliably.

In the present invention, it is preferable that the high-rigidity portion is formed in a substantially rectangular shape in plan view, and the cutout portion is parallel to the side of the substantially rectangular-shaped high-rigidity portion and is shorter than the length of the side. It extends in length.
In the present invention configured as described above, the high-rigidity portion is formed in a substantially square shape in plan view, and the cutout portion is parallel to the side of the substantially rectangular-shaped high-rigidity portion and is longer than the length of the side. It extends with a short length. Here, if the highly rigid portion is formed in a substantially rectangular shape in plan view, the region where the vibration energy is not concentrated and the vibration distortion is reduced is located on the side of the substantially rectangular high rigid portion. It was found to extend parallel to the length and shorter than the length of the side. Therefore, according to the present invention, the cutout portion extends in parallel to the side of the high-rigidity portion formed in a substantially square shape in plan view and shorter than the length of the side. The effect of reduction can be obtained more reliably.

In the present invention, preferably, the cutout portion is not formed in the corner region of the low-rigidity portion.
In the present invention configured as described above, the cutout portion is not formed in the corner region of the low rigidity portion. Here, the inventors have found that the region where the vibration energy is not concentrated and the vibration distortion is small does not occur in the corner region of the low rigidity portion. Therefore, according to the present invention, since the cutout portion is not formed in the corner region of the low-rigidity portion, the above-described effect of reducing vibration energy is not impaired.

  ADVANTAGE OF THE INVENTION According to this invention, the vibration energy of a floor panel by the vibration transmitted from the frame member of the vehicle body can be reduced effectively, and the acoustic radiation from a floor panel can be reduced.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a perspective view showing an underbody of an automobile provided with an embodiment of the present invention. As shown in FIG. 1, an underbody 1 of an automobile includes a plurality of floor panels 2, 4, 6, 8, 10, 12, 14, and 16 that form a floor portion (floor portion) of a passenger compartment, and these floors. And a plurality of frame members connected to the panel. The plurality of frame members include a front side frame 18, a side sill 20, a floor side frame 22, a rear side frame 24 that extend in the longitudinal direction of the vehicle body, and a No. 2 frame that extends in the vehicle width direction. 1 to No. No. 9 cross members 26 to 34 and No. 9 extending between the cross members and extending in the longitudinal direction of the vehicle body. 1 to No. Three tunnel side members 36-38.

First, the frame member will be described with reference to FIG. A pair of front side frames 18 having a closed cross-sectional structure extending in the longitudinal direction of the vehicle body so as to surround the engine room from both the left and right sides are provided at a front portion of the underbody 1 of the automobile. These front side frames 18 have a closed cross-section No. at the front end of the vehicle body. One cross member 26 is joined, and an engine 40 and a front suspension cross member 42 are attached to the front side frame 18, and a front suspension 44 is attached to the front suspension cross member 42.
The rear end portions of the pair of front side frames 18 are No. 1 extending in the vehicle width direction at the end portion of the floor portion on the vehicle body front side. 2 It is joined to the cross member 27. This No. The two cross members 27 are attached to a downward inclined portion of a dash panel (not shown) that partitions the vehicle compartment and the engine compartment, and a pair of torque box members 27a having a closed cross-sectional structure provided outside the vehicle body of each front side frame 18. And a dash lower cross member 27b having a closed cross-sectional structure disposed so as to be sandwiched between the front side frames 18.

  This No. 2 The pair of side sills 20 provided on the floor portion behind the vehicle body from the cross member 27 has a closed cross-sectional structure, and the front end portion thereof is No.2. The two cross members 27 are joined to both ends in the vehicle width direction. A pair of U-shaped floor side frames 22 extending in the longitudinal direction of the vehicle body are provided between the side sills 20, and the front end portions of the floor side frames 22 are connected to the rear end portions of the front side frames 18. In addition to being joined, 2 It is joined to the cross member 27. These floor side frames 22 are No. 3 cross member 28 and no. 4 so that it protrudes inward in the vehicle width direction between the cross member 29 and 22a. The connecting portion 30a with the 5 cross member 30 is bent in the vehicle width direction, and the other portions extend linearly.

  The rear end portions of the floor side frames 22 are joined to the front end portions of the rear side frames 24 each having a U-shaped cross section and extending in the longitudinal direction of the vehicle body. Further, the front end portions of these rear side frames 24 bend outward in the vehicle width direction, and are also joined to the inner side surface of the side sill 20 in the vehicle width direction. The front end portion has a reinforcing member extending in the vehicle width direction. 24a is provided. These rear side frames 24 extend to the end edge of the floor portion on the rear side of the vehicle body. No. 7 cross member 32 and No. 7 A rear suspension cross member 46 is attached between the eight cross members 33 and a rear suspension 48 is attached to the rear suspension cross member 46.

  No. No. 2 on the vehicle body rear side of the cross member 27. 2 extends in a straight line in the vehicle width direction parallel to the cross member 27. Three cross members 28 are provided. This No. The three cross members 28 are joined to the side sills 20 at both left and right ends in the vehicle width direction, and intersect the floor side frame 22 and are joined to the floor side frame 22 on both the left and right sides in the vehicle width direction. This No. No. 3 on the vehicle body rear side of the cross member 28. No. 3 which extends linearly in the vehicle width direction parallel to the cross member 28 Four cross members 29 are provided, and both left and right end portions in the vehicle width direction are joined to the side sill 20 in the vicinity of the pillars 35. No. The four cross members 29 intersect with the floor side frame 22 on both the left and right sides in the vehicle width direction and are joined to the floor side frame 22. These No. 3 and no. The four cross members 28 and 29 protrude upward at a substantially central position in the vehicle width direction where the floor tunnel portion 50 is provided.

No. No. 4 on the vehicle body rear side of the cross member 29. 5 cross member 30, No. 5 6 cross member 31, No. 6 7 cross members 32 are provided, and the cross members 30 to 32 extend linearly in the vehicle width direction in parallel to each other. This No. The left and right ends of the cross member 30 in the vehicle width direction are joined to the floor side frame 22 respectively. 6 and no. The left and right ends in the vehicle width direction of the seven cross members 31 and 32 are joined to the rear side frame 24, respectively. No. 7 on the rear side of the vehicle body of the cross member 32, the center of the vehicle width direction is curved forward. Eight cross members 33 are provided so as to extend in the vehicle width direction, and left and right end portions in the vehicle width direction are respectively joined to the rear side frame 24.
This No. On the rear side of the vehicle body of the 8 cross member 33, a No. of closed cross-sectional structure that extends linearly in the vehicle width direction at the edge of the floor portion on the rear side of the vehicle body. Nine cross members 34 are provided, and both left and right ends in the vehicle width direction are joined to the rear ends of the rear side frame 24, respectively.

  In addition to the front side frame 18, the side sill 20, the floor side frame 22, and the rear side frame 24 described above as reinforcing members in the longitudinal direction of the vehicle body, the vehicle body longitudinal direction is provided at both edges of the floor tunnel portion 50 in the vehicle width direction. No. with a U-shaped cross section 1 to No. Three tunnel side members 36 to 38 are disposed. No. 1 tunnel side member 36 is No.1. 2 cross member 27 and No. 2 3 extends linearly across the cross member 28, and both end portions in the longitudinal direction of the vehicle body are respectively No. 2 cross member 27 and No. 2 3 It is joined to the cross member 28. No. 2 The tunnel side member 37 is 4 cross member 29 and no. 5 extends linearly between the cross member 30 and both end portions in the longitudinal direction of the vehicle body are respectively No. 5 and No. 5 cross members 30. 4 cross member 29 and no. 5 is joined to the cross member 30. No. 3 tunnel side member 38 is No.3. 6 cross member 31 and No. 6 7 extends linearly across the cross member 32, and both ends in the longitudinal direction of the vehicle body are respectively No. 7 and No. 7 cross member 32. 6 cross member 31 and No. 6 7 is joined to the cross member 32.

  The frame member having the U-shaped cross section described above, that is, the floor side frame 22, the rear side frame 24, No. 2 3 to No. 8 cross members 28 to 33 and No. 8 1 to No. Each of the three tunnel side members 36 to 38 is formed such that an open portion having a U-shaped cross section faces upward of the vehicle body, and the lower surface of each floor panel 2, 4, 6, 8, 10, 12, 14, 16 is These are joined to the flange portion of each frame member to form a substantially rectangular closed cross section.

Next, the floor panel will be described with reference to FIG. As shown in FIG. 1, an underbody 1 of an automobile is provided with first to eighth floor panels 2, 4, 6, 8, 10, 12, 14, and 16 each integrally formed by press-molding steel plates. .
The first floor panel 2 is No. 2 cross member 27, a pair of side sills 20, and A floor tunnel portion 50 is provided so as to cover the space surrounded by the three cross members 28 and bulges upward so as to extend in the vehicle longitudinal direction at a substantially central position in the vehicle width direction. The front edge of the first floor panel 2 is No. 2 is joined to the vehicle body rear side surface of the cross member 27, and the bottom surfaces of the remaining three sides are connected to the pair of side sills 20 and No. 2 side sill 20. 3 on the left and right sides in the vehicle width direction. The lower surface of the 1 tunnel side member 36 and the floor side frame 22 are joined.
In this embodiment, the floors on the left and right sides of the floor tunnel portion 50 in the vehicle width direction are formed in symmetrical shapes, and only the panel on one side will be described below, and the other side will be described. Description of the panel will be omitted.

In addition, the first floor panel 2 has a No. 1 on both the left and right sides of the floor tunnel portion 50. 2 cross member 27 and No. 2 A bent portion 52 is formed extending in a straight line shape in the vehicle width direction in parallel with the three cross member 28. The bent portion 52 is bent in a straight line so that the first floor panel 2 extends in a dogleg shape in the longitudinal direction of the vehicle body.
The first floor panel 2 is formed with panel regions S1 to S4 surrounded by the frame members 20, 22, 27, 28, and 36 and the bent portion 52, respectively. Among these regions, the panel regions S3 and S4 extend obliquely upward toward the rear of the vehicle body with respect to the panel regions S1 and S2 (see FIG. 6B).

The second floor panel 4 is No. 3 cross member 28, a pair of side sills 20, and A floor tunnel portion 50 is provided so as to cover the space surrounded by the four cross members 29 and bulges upward so as to extend in the vehicle longitudinal direction at a substantially central position in the vehicle width direction. As for this 2nd floor panel 4, the lower surface of the edge of the 4 sides is No.2. 3 cross member 28, a pair of side sills 20, and The lower surface is bonded to the floor side frame 22 on both the left and right sides in the vehicle width direction.
In addition, a fold portion 54 that is bent in a straight line is formed at both edges in the vehicle width direction of the floor tunnel portion 50 of the second floor panel 4, and the floor tunnel portion 50 rises from the fold portion 54.
In the second floor panel 4, panel regions S5 and S6 surrounded by the frame members 20, 22, 28, 29, the bent portion 54, and the bead portion 56 are formed, respectively.

The third floor panel 6 is No. 4 cross member 29, floor side frame 22 and No. 4 A floor tunnel portion 50 is formed so as to cover the space surrounded by the five cross members 30 and bulges upward so as to extend in the vehicle longitudinal direction at a substantially central position in the vehicle width direction. As for this 3rd floor panel 6, the lower surface of the edge part of the 4 sides is No.2. 4 cross member 29, each floor side frame 22, and No. 4 cross member 29. 5 on each of the left and right sides in the vehicle width direction. The lower surface of the 2 tunnel side member 37 is joined.
In addition, the third floor panel 6 has a No. 3 on both the left and right sides of the floor tunnel portion 50. 4 cross member 29 and no. A bead portion 58 extending linearly in the vehicle width direction is formed in parallel with the five cross member 30. The bead portion 58 is formed by protruding the third floor panel 6 itself upward of the vehicle body.
Panel regions S7 and S8 surrounded by the frame members 22, 29, 30, 37 and the bead portion 58 are formed in the third floor panel 6, respectively.

The fourth floor panel 8 is provided outside the third floor panel 6 in the vehicle width direction. 4 extends in the longitudinal direction of the vehicle body so as to cover the space surrounded by the cross member 29, the side sill 20, the floor side frame 22, and the rear side frame 24. It extends to the vicinity of the 8 cross member 33. These fourth floor panels 8 are joined to the frame members 20, 22, 24, and 29.
The fifth floor panel 10 is No. 5 cross member 30, No. 5 6 The cross member 31, the pair of floor side frames 22 and the pair of rear side frames 24 are provided so as to cover the space, and the lower surfaces of the edges of the four sides are the frame members 22, 24, 30 respectively. , 31.
In addition, a fold portion 54 that is bent in a straight line is formed at both edges in the vehicle width direction of the floor tunnel portion 50 of the fifth floor panel 10, and the floor tunnel portion 50 rises from the fold portion 54.
The fifth floor panel 10 is formed with a panel region S9 surrounded by the frame members 22, 24, 30, 31, and the bent portion 54.

The sixth floor panel 12 is No. 6 cross member 31, No. 6 7 is provided so as to cover the space surrounded by the cross member 32 and the pair of rear side frames 24, and the lower surfaces of the edges of the four sides are respectively joined to the frame members 24, 31, 32, On both the left and right sides in the vehicle width direction, no. The lower surface of the three tunnel side member 38 is joined.
The sixth floor panel 12 is formed with a panel region S10 surrounded by the frame members 24, 31, 32, and 37.
The seventh floor panel 14 is No. 7 cross member 32, no. It is provided so as to cover the space surrounded by the eight cross members 33 and the pair of rear side frames 24, and the lower surfaces of the edge portions of the four sides are joined to the frame members 24, 32 and 33, respectively.
The eighth floor panel 16 is No. 8 cross member 33, no. 9 is provided so as to cover the space surrounded by the cross member 34 and the pair of rear side frames 24, and the lower surfaces of the edge portions of the four sides are joined to the frame members 24, 33 and 34, respectively.

In such an underbody 1 of an automobile, vibrations of the engine 40, the front suspension 44, and the rear suspension 48 are respectively transmitted through a pair of floors via the front suspension cross member 42, the front side frame 18, and the rear suspension cross member 46. Largely transmitted to the side frame 22 and the rear side frame 24, and further transmitted to the cross members 26 to 34, the side sill 20, and the tunnel side members 36 to 38, and these vibrations are transmitted to the first to eighth floor panels 2, 4, 6, 8, 10, 12, 14, 16. As described above, the vibration transmitted to each floor panel is mainly a vibration of 400 Hz or less having a peak at a frequency in the vicinity of 250 Hz, which is road noise caused by tire cavity resonance. Acoustic radiation from the panel is generated, which becomes a factor of worsening vibration noise in the passenger compartment.
In the embodiment of the present invention, the vibration reduction structure is provided in each of the panel regions S1 to S4, S7, S8, and S10 of the floor panels 2, 6, and 12, thereby radiating from those panel regions by the vibration transmitted from the frame member. The sound radiation is suppressed. In addition, the floor panels 4, 8, 10, 14, and 16 are configured by conventional panels.

  Here, the vibration reducing structure will be described. The vibration reduction structure includes a predetermined high rigidity portion (high rigidity portion) and a predetermined low rigidity portion (low rigidity portion) provided in a predetermined panel region of a floor panel surrounded by a frame member or the like. It is comprised with the damping material provided in the low-rigidity part. The vibration energy transmitted from the frame member to the panel area is concentrated on the low rigidity part due to the difference in rigidity between the high rigidity part and the low rigidity part, and along with the large vibration distortion caused by this concentrated vibration energy. When the damping material is distorted, vibration energy is converted into heat energy or the like and reduced. Moreover, vibration energy is reduced also by the damping ability of the material (for example, steel plate) which comprises a floor panel. Due to such vibration reduction effect, the acoustic radiation radiated from each panel region is effectively reduced.

Next, with reference to FIGS. 2 and 3, the effect of reducing acoustic radiation by the vibration reducing structure obtained by experiments will be described. FIG. 2 is a plan view (a) showing an experimental model of a floor panel having a vibration reducing structure and a cross-sectional view (b) taken along the line AA, and FIG. 3 is an experimental model of FIG. 2 and a conventional panel. It is a diagram which shows the experimental result obtained from this experimental model.
As shown in FIG. 2, the experimental model is obtained by providing a panel 62 having a vibration reducing structure on an experimental frame member 60 having a rectangular cross section arranged in a square shape when viewed from above. The panel 62 is formed by press-molding a steel plate used in an actual vehicle, and the size of the panel surrounded by the frame member 60 is about 300 mm in length and width. Yes. The panel 62 is formed with a high-rigidity portion 64 and a flat low-rigidity portion 66 around the high-rigidity portion 64, and a damping material 68 is attached to the low-rigidity portion 66.

In addition, as a conventional panel, an experimental model in which a frame member 60 having a flat surface formed of a steel plate having the same thickness as the panel 62 was provided on the frame member 60 (not shown) was also prepared. The same amount of vibration damping material as that of the panel 62 was pasted on the entire surface of this conventional panel. In the experiment, a part of the frame member 60 to which the floor panel is attached is given a vibration force of a frequency of 500 Hz or less (white noise) with a vibrator, and the vibration magnitude of the panel with respect to the vibration magnitude of the frame. The ratio (vibration rate) was measured.
As shown in FIG. 3, the vibration rate of the panel 62 having the vibration reduction structure is lower than that of the conventional panel over a relatively wide range of a frequency of 400 Hz or less, and particularly, road noise caused by tire cavity resonance. As a result, the peak height appearing in the vicinity of 250 Hz is greatly reduced. Therefore, it can be said that the acoustic radiation radiated from the panel is reduced by the vibration reducing structure.

Next, the effect of concentration of vibration energy on the low rigidity portion obtained by FEM analysis will be described with reference to FIG. FIG. 4 shows the result of vibration analysis of an analysis model obtained by converting the experimental model of FIG. 2 into a finite element model by omitting the damping material. The analysis result shown in FIG. 4 shows that the vibration distortion increases as the brightness increases.
As shown in FIG. 4, the vibration strain is small in the high rigidity portion 74 surrounded by the broken line in the figure, and on the other hand, the vibration distortion is large in the surrounding low rigidity portion 76, and vibration energy is largely concentrated in the low rigidity portion 76. You can see that The peripheral edge 74a of the high-rigidity portion 74, that is, a region 74a of the high-rigidity portion 74 adjacent to the boundary between the high-rigidity portion 74 and the low-rigidity portion 76 also has high brightness and vibration distortion. It is getting bigger. Therefore, it can be seen from this analysis result that when the damping material is provided, the damping material may be provided in the low rigidity portion where the vibration energy is concentrated. Moreover, it can be said from this analysis result that if the damping material is provided so as to be in contact with the peripheral portion of the high-rigidity portion, the above-described vibration reduction effect can be effectively obtained.

  On the other hand, the low-rigidity portion 76 includes four corner regions 76a (partially indicated by imaginary lines) and four intermediate regions 76b (partially indicated by imaginary lines) between the corner regions 76a. In the intermediate region 76b, there are regions 76c where vibration distortion is small or not generated, and it can be seen that vibration energy is not concentrated in these regions 76c. The regions 76 c where the vibration energy is not concentrated are generated at positions away from the frame portion 70 and the high-rigidity portion 74 and at positions closer to the frame portion 70 than the high-rigidity portion 84. The region 76 c extends linearly in parallel with each side of the frame portion 70 and the high rigidity portion 74, and the length thereof is shorter than each side of the high rigidity portion 74.

Here, the vibration energy is reduced by being converted into other thermal energy or the like when the damping material is distorted along with the vibration distortion of the floor panel. However, when the damping material is provided in the low-rigidity part, the damping is performed over both the region where the vibration energy is concentrated and the vibration distortion is large and the region where the vibration energy is not concentrated and the vibration distortion is small or not generated (76c). When the vibration material is provided, distortion of the vibration damping material provided in a region where vibration distortion is large is suppressed. That is, since the vibration damping material provided in the region where the vibration distortion is small or not generated does not distort, the vibration damping material provided in the adjacent region where the vibration distortion is large is hardly distorted, and the vibration energy generated by the vibration damping material is reduced. This will reduce the reduction effect.
Therefore, in the present embodiment, the vibration reduction structure according to the embodiment of the present invention is provided in the above-described panel regions S1 to S4, S7, S8, and S10 based on these results.

Next, the embodiment of the present invention will be specifically described with reference to FIGS.
FIG. 5 is an enlarged plan view (a) showing the panel region S10 according to the present embodiment and a sectional view (b) showing a sectional structure in the vehicle width direction of the panel region S10 as seen along the VV line. 6 is an enlarged plan view (a) showing the panel regions S1 and S3 and a cross-sectional view (b) in the longitudinal direction of the vehicle body seen along the VI-VI line. FIG. 7 shows the panel regions S7 and S8. FIG. 2 is an enlarged plan view (a) showing the vehicle body and a cross-sectional view (b) in the longitudinal direction of the vehicle body viewed along the line XII-XII.
Since the basic shape and arrangement of the vibration reduction structure provided in each of the panel areas S1 to S4, S7, S8, and S10 are the same, first, the panel area S1 will be described first, followed by the panel area S1. About S4, S7, and S8, a different point from panel area | region S10 is mainly demonstrated.

First, the vibration reduction structure provided in the panel region S10 will be described with reference to FIG.
As shown in FIG. 5A, the panel region S10 is formed surrounded by the frame members 24, 31, 32, and 38, and the frame members 24, 31, 32, and 38 extend linearly and face each other. The frame members are formed in a rectangular shape extending in parallel to each other.
In the panel region S10, a substantially rectangular high-rigidity portion 84 is formed at the center thereof, and the high-rigidity portion 84 has four sides extending linearly that form a boundary with the low-rigidity portion 76. ing. A low-rigidity portion 86 extending in a square shape is formed in the entire area around the high-rigidity portion 84.
As shown in FIG. 5 (b), the high-rigidity portion 84 is formed by protruding the floor panel itself upward of the vehicle body to enhance the rigidity. Specifically, the cross-sectional shape of the cross section is substantially flat at the center, and its periphery rises from the low rigidity portion 86 at a discontinuous angle and extends in a curved shape. The high-rigidity portion 84 may protrude downward from the vehicle body. On the other hand, the low-rigidity part 86 is formed substantially flat.

Further, as shown in FIGS. 5A and 5B, the low-rigidity portion 86 is provided with a vibration damping material 88 over almost the entire area thereof. In the present embodiment, the vibration damping material 88 is an asphalt vibration damping material, and has a substantially rectangular opening along the outer peripheral edge (boundary with the low rigidity portion 86) of the high rigidity portion 92 and has a low rigidity. It is formed in a sheet shape so as to extend in a square shape according to the outer shape of the portion 94, and is attached to the low-rigidity portion 86.
The vibration damping material 88 has a cutout portion 88c. These cutout portions 88c are formed in positions and shapes corresponding to the above-described region 86c where the vibration energy is not concentrated. In the low-rigidity portion 86 of the panel region S10, as shown in FIG. 5A, four corner regions 86a (only a part is indicated by phantom lines) and four intermediate regions 86b (partially) The vibration energy is concentrated on the portion excluding the region 86c in (only indicated by a virtual line), and the vibration energy is not concentrated on the region 86c. Therefore, in this embodiment, the vibration damping material 88 is not provided in the region 86c, and the vibration damping material 88 is provided only in the portion where the vibration energy is concentrated, so that the vibration energy can be reduced more effectively. I have to.

Specifically, the cut-out portion 88c is formed at a position separated from each frame member 24, 31, 32, 38 and the high rigidity portion 74, and at a position closer to each frame member than the high rigidity portion 84. Has been. The cut-out portion 88c extends linearly in parallel to each side of the frame members 24, 31, 32, 38 and the high-rigidity portion 74 (four sides at the boundary with the low-rigidity portion 86). In addition, it is formed shorter than each side of the high rigidity portion 74.
By forming the cutout portion 88c in this manner, the damping material 88 is provided only in a region where the vibration energy is concentrated, that is, only in a portion excluding the region 86c in the corner region 86a and the intermediate region 86b of the low rigidity portion 86. In particular, the cutout portion 88c is not formed in the corner region 86b where the vibration energy is concentrated.

  As shown in FIG. 5B, the damping material 88 is provided so as to be in contact with the peripheral portion 84 a of the high-rigidity portion 84, and also reduces the vibration energy of the peripheral portion 84 a of the high-rigidity portion 84. You can do that. Further, the damping material 88 may be another damping material such as a coating type damping material. For example, in the case of a coating-type damping material, the coating-type damping material is applied to almost the entire surface of the low-rigidity portion so that the cut-out portion is formed so as not to be applied to a region where vibration energy is not concentrated. To do.

Next, the vibration reduction structure provided in the panel regions S1 to S4 will be described with reference to FIGS.
As shown in FIG. 6A, the panel regions S1 and S3 share a fold 52, and the panel region S1 is surrounded by the fold 52 and the frame members 20, 22, and 27 in a rectangular shape. Is formed. As shown in FIG. 1, the panel regions S2 and S4 are surrounded by the frame members 22, 27, 28, and 36 and the bent portion 52, and are formed in the same manner as the panel regions S1 and S3. Here, the bent portion 52 is formed by bending the first floor panel 2 in a straight line so that vibration generated in the panel region S1 or S2 and vibration generated in the adjacent panel region S3 or S4 are not coupled to each other. It plays a role as a vibration regulating part that regulates vibration.
As shown in FIG. 1 and FIG. 6A, the panel areas S1 to S4 have a substantially rectangular high-rigidity portion 84 and a rectangular shape and a flat cross section, as in the panel area S10 described above. A low rigidity portion 86 is formed. Further, as shown in FIG. 6B, among the high rigidity portions 84 formed in the panel regions S1 to S4, the high rigidity portion 84 formed in the panel region S3 has a curved surface height continuously. It is formed to have a changing dome-like cross-sectional shape. Although not shown, the high rigidity portion 84 formed in the panel region S4 is also formed in the same manner.
Further, in these panel regions S1 to S4, a damping material 88 having a cutout portion 88c is provided in almost the entire region of the low-rigidity portion 86. Also in these panel regions S1 to S4, each cutout portion 88c is formed in a position and shape corresponding to the region where the vibration energy is not concentrated, and more effectively reduces the vibration energy of the panel regions S1 to S4. You can do that.

In particular, these panel regions S1 to S4 have one side in contact with the bent portion 52, but the bent portion 52 is bent in a straight line, and its rigidity is enhanced, so that it is a frame member. Similarly, a region where vibration energy is not concentrated occurs at a position away from the bead portion 58 by a predetermined distance. Therefore, as in the panel region S10 described above, the vibration energy of the panel regions S1 to S4 is more effectively reduced by forming the cutout portion 88c in that region.
As in the panel regions S1 to S4 described above, the vibration energy is reduced by the vibration reducing structure of the present embodiment also in the region surrounded by the bent portion 52 that is the vibration restricting portion in addition to the frame member. Can be done.

Next, the vibration reduction structure provided in the panel regions S7 and S8 will be described with reference to FIG.
As shown in FIG. 7A, the panel regions S7 and S8 share the bead portion 58, and the panel region S7 is formed by being surrounded by the bead portion 58 and the frame members 22, 29, 30, and 37. Has been. In these panel regions S7 and S8, the frame member 22 and the frame member 37 are not parallel to each other, and the panel regions S7 and S8 are trapezoidal. Here, the bead portion 58 serves as a vibration restricting portion that restricts vibration so that vibration generated in the panel region S7 and vibration generated in the adjacent panel region S8 are not coupled to each other.
As shown in FIG. 7A, a high-rigidity portion 84 and a low-rigidity portion 86 are formed in the panel regions S7 and S8. The high-rigidity portion 84 is formed so that each side thereof is parallel to each frame member 22, 29, 30, 50, or the bead portion 58, and is formed in a trapezoidal shape substantially similar to the shape of each panel region S7 and S8. Has been. The low-rigidity portion 86 is formed so as to extend in a substantially square shape around the entire periphery of the high-rigidity portion 84. As described above, in the panel regions S7 and S8, each side of the high-rigidity portion 84 is formed to be parallel to each frame member 22, 29, 30, 50, or the bead portion 58, and the surrounding low-rigidity portion is formed. As a result, the vibration energy is surely concentrated on the low rigidity portion 86.

Moreover, as shown in FIG.7 (b), the high rigidity part 84 formed in panel area | region S7 is formed so that it may become a dome-shaped cross-sectional shape from which curved surface height changes continuously, although not shown in figure, The panel region S8 is also formed in the same shape. Further, the low rigidity portion 86 is formed flat like the panel region S10.
Further, in these panel regions S7 and S8, a damping material 88 having a cutout portion 88c is provided in almost the entire region of the low-rigidity portion 86. Also in these panel regions S7 and S8, each cutout portion 88c is formed in a position and shape corresponding to the region where the vibration energy is not concentrated, and the vibration energy in the panel regions S7 and S8 is more effectively reduced. You can do that.

In particular, these panel regions S7 and S8 are in contact with the bead portion 58 on one side, but since the bead portion 58 has increased rigidity, the bead portion 58 can be removed from the bead portion 58 as in the case of the frame member. A region where vibration energy is not concentrated occurs at a position away from the predetermined distance. Therefore, similarly to the panel region S10 described above, the vibration energy of the panel regions S7 and S8 is more effectively reduced by forming the cutout portion 88c in the region.
Further, the region where the vibration energy is not concentrated extends parallel to the frame member. Therefore, even if the panel region is not a rectangular shape (the trapezoidal shape in the panel regions S7 and S8), the cutout portion 88c is formed so as to be parallel to each frame member and the bead portion 58. Energy can be reduced effectively.

  Like these panel regions S7 and S8 described above, the vibration energy is reduced by the vibration reducing structure of the present embodiment also in the region surrounded by the bead portion 58 as the vibration restricting portion in addition to the frame member. Can be done. Further, even when the panel region is a non-rectangular quadrangular shape, the high-rigidity portion is formed in a quadrangular shape that is substantially similar to the shape of the panel region, and the vibrational energy of the low-rigidity portion 86 is not concentrated in the region. Correspondingly, by providing the cutout portion 88c of the damping material 88, vibration energy can be reduced.

Next, the effect of this embodiment is demonstrated.
In the panel regions S1 to S4, S7, S8, and S10 of the present embodiment, the high rigidity portion 84 and the low rigidity portion 86 formed around the high rigidity portion 84 are provided. The vibration energy is concentrated on the low rigidity portion 86 due to the difference in rigidity between the low rigidity portion 84 and the low rigidity portion 86. And the vibration damping material 88 provided in the low-rigidity part 84 is distorted with the distortion of the low-rigidity part 86, and the vibration energy concentrated on the low-rigidity part 86 is converted into thermal energy, and the vibration of each of the panel regions as a whole. Energy is reduced. As a result, acoustic radiation from those panel areas is reduced.

  In particular, since the cutout portion 88c is formed in the damping material 88 corresponding to the region 86c where the vibration energy of the low-rigidity portion 86 is not concentrated, the vibration energy can be more effectively reduced. That is, the vibration distortion is increased as described above by not providing the damping material 88 over the region where the vibration energy is not concentrated and the vibration distortion is small or not generated and the region where the vibration distortion is large. It is possible to prevent the vibration damping material provided in the existing area from becoming difficult to be distorted. And the damping material 88 will be provided only in the area | region where vibration energy concentrates, and vibration energy can be reduced more effectively. Furthermore, the weight of the damping material can be reduced by providing the cutout portion 88c.

It is a perspective view which shows the underbody of the motor vehicle provided with embodiment of this invention. It is the top view (a) which shows the experimental model of the floor panel which has a vibration reduction structure, and sectional drawing (b) seen along the AA line. It is a diagram which shows the experimental result obtained from the experimental model of FIG. 2, and the experimental model of the conventional panel. It is a result of the vibration analysis of the analysis model which omitted the damping material from the experimental model of FIG. FIG. 5 is an enlarged plan view (a) showing a panel region S10 according to the present embodiment and a sectional view (b) showing a cross-sectional structure in the vehicle width direction of the panel region S10 as viewed along the line VV. FIG. 5 is an enlarged plan view (a) showing the panel regions S1 and S3 according to the present embodiment and a cross-sectional view (b) in the front-rear direction of the vehicle body viewed along the VI-VI line. It is the expanded plan view (a) which shows panel area | region S7 and S8 by this embodiment, and sectional drawing (b) of the vehicle body front-back direction seen along the XII-XII line | wire.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Automobile underbody 2 1st floor panel 6 3rd floor panel 12 6th floor panel 18 Front side frame 20 Side sill 22 Floor side frame 24 Rear side frames 26-34 1-No. 9 Cross members 36-38 1-No. 3 tunnel side member 40 engine 42 front suspension cross member 46 rear suspension cross member 52 bent portion (vibration restricting portion)
58 Bead part (vibration regulation part)
64, 74, 84 High rigidity parts 66, 76, 86 Low rigidity parts 68, 78, 88 Damping materials S1 to S10 Panel region

Claims (4)

A floor panel structure of a vehicle body constituting a floor of an automobile by floor panels connected to a plurality of frame members arranged in the vehicle longitudinal direction and the vehicle width direction,
The floor panel is formed with a panel region at least part of which is surrounded by the frame member,
In the panel region of the floor panel, a high-rigidity portion that protrudes upward or downward is formed at the center of the panel region, and a low-rigidity portion is formed around the high-rigidity portion. ,
The low-rigidity portion is provided with a vibration damping material, and the vibration damping material is formed with a cutout portion extending along the frame member at a position separated from the frame member. Construction. The frame member extends linearly,
The vehicle body floor panel structure according to claim 1, wherein the cutout portion extends parallel to the linearly extending frame member. The high rigidity portion is formed in a substantially quadrangular shape in plan view,
The vehicle floor panel structure according to claim 1, wherein the cutout portion extends in parallel to a side of the substantially rectangular high-rigidity portion and has a length shorter than a length of the side.   The floor panel structure of a vehicle body according to any one of claims 1 to 3, wherein the cut-out portion is not formed in a corner region of the low-rigidity portion.

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