JP4395738B2 - Car body floor panel structure - Google Patents

Description

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

  Vibration from the frame member to which the engine and suspension are connected is transmitted to the floor panel, and this floor panel vibrates. As a result, unpleasant vehicle interior vibration and noise are generated by greatly vibrating the air in the vehicle interior. It is known. 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.

  Conventionally, in order to suppress these vibration noises, damping materials and vibration-proofing materials are generally pasted as various vibration-proofing and sound-proofing measures on each part of the floor panel and the vehicle body in the vicinity thereof. . This can reduce vibration and noise, but on the other hand, it requires a very large amount of damping material and anti-vibration material, which increases the weight of the vehicle, thereby causing various adverse effects and costs. There was a big problem.

  Furthermore, unpleasant vibrations transmitted from the engine and suspension are mainly 400 Hz or less in automobiles, and particularly have a peak at a frequency around 250 Hz, which is road noise caused by tire cavity resonance. It is also known to increase the rigidity by forming a large number of beads 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.

  In this case, there is an advantage that the resonance peak in the low frequency region can be suppressed, but on the other hand, the vibration in the high frequency region increases on the contrary, so that a damping material and a vibration isolating material for suppressing vibration noise in the high frequency region are provided. Like the above, the vehicle weight is increased and the vehicle weight is increased. As a result, there are various adverse effects and costs, and it has been desired to solve this problem.

  On the other hand, 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, since exhaust pipes and accessories are arranged below and above the vehicle body of the floor panel, it is necessary to form the convex portions formed on the floor with a height and arrangement so as not to interfere with them. . Moreover, it is necessary to suppress the convex part of the floor to a certain height in order to secure the foot comfort of the passenger. Furthermore, the convex portion of the floor needs to be formed in a size that can be accommodated in a floor panel having a certain shape and size surrounded by the frame member. Due to such restrictions on the vehicle body structure or processing, it may be difficult to reduce the vibration by applying the vehicle body panel structure described in Patent Document 1.

  Therefore, the present invention has been made to solve the above-described problems of the prior art, and effectively reduces the vibration energy of the floor panel due to vibration transmitted from the frame member of the vehicle body, so that the sound from the floor panel can be reduced. 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 at least part of which is surrounded by a frame member, and the floor panel is formed around an opening formed at a substantially central portion of the panel region and around the opening. A lid member having rigidity and / or weight increased from that of the peripheral part, and the lid member and opening part having higher rigidity than the peripheral part. It is characterized in that it is configured as a high weight part with increased weight and / or weight, and the peripheral part is configured as a low rigidity part and / or a low weight part.
In the present invention configured as above, the lid member and the opening are configured as a high-rigidity part and / or a high-weight part and the peripheral part is configured as a low-rigidity part and / or a low-weight part. The vibration energy can be concentrated on the peripheral part due to the difference in rigidity between the rigid part and the low rigidity part and / or the difference in weight between the high weight part and the low weight part. The vibration energy is converted into heat energy by the damping ability of the material constituting the floor panel at the periphery where the vibration energy is concentrated. As a result, vibration energy in the panel region is reduced, and acoustic radiation from the panel region can be reduced.
Moreover, since the lid member is formed separately from the floor panel and is fixed to the opening, the high rigidity portion and / or the high weight portion can be easily formed. In addition, by forming the lid member as a separate body, it is easy to greatly increase the rigidity and / or weight of the lid member, the difference in rigidity between the high-rigidity portion and the low-rigidity portion, and / or the high-weight portion and the low-weight portion. And the weight difference can be increased. Therefore, even if there are restrictions on the body structure or processing such as the height, arrangement, and size as described above, the vibration energy in the panel region is effectively reduced by greatly increasing the rigidity difference and / or the weight difference. It can be reduced.

In the present invention, preferably, a stepped portion protruding downward is formed in the opening, and a lid member is fixed to the stepped portion.
In the present invention configured as described above, a stepped portion protruding downward is formed in the opening, so that the rigidity of the opening can be increased, and the difference in rigidity between the high rigidity portion and the low rigidity portion can be reduced. It can be enlarged more reliably. Further, since the stepped portion protrudes downward, it is possible to easily remove the cationic coating electrodeposition liquid at the time of manufacturing the floor panel, and then, by fixing the lid member to the stepped portion, rigidity and / or Alternatively, it is possible to easily form a highly rigid portion whose weight is greatly increased.

In the present invention, preferably, the lid member has a projecting portion integrally formed by projecting upward or downward along substantially the entire circumference of the peripheral portion.
In the present invention configured as described above, the lid member has a projecting portion integrally formed by projecting upward or downward along substantially the entire circumference of the peripheral edge portion thereof. In particular, the rigidity against bending and twisting can be greatly increased. As a result, the difference in rigidity between the high-rigidity portion and the low-rigidity portion can be increased, and vibration energy can be reliably concentrated on the peripheral portion to reduce vibration.

In the present invention, preferably, the thickness of the lid member is larger than the thickness of the peripheral portion.
In the present invention configured as described above, the plate thickness of the lid member is larger than the plate thickness of the peripheral portion, so that its rigidity and weight can be increased more than those of the peripheral portion. As a result, the rigidity difference between the high-rigidity part and the low-rigidity part and / or the weight difference between the high-weight part and the low-weight part can be increased. Can be reduced.

  ADVANTAGE OF THE INVENTION According to this invention, the vibration energy of the floor panel transmitted from the frame member of a 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 first to fourth embodiments of the present invention.
As shown in FIG. 1, an underbody 1 of an automobile includes a plurality of frame members and a plurality of floor panels 2, 4, 6, 8 connected to these frame members and constituting a floor portion (floor portion) of a passenger compartment. 10, 12, 14, 16.

  First, the frame member will be described with reference to FIG. As shown in FIG. 1, the 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 vehicle longitudinal direction, 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.

  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. At the front end of the vehicle body of these front side frames 18, a closed cross-sectional structure No. 1 which is a reinforcing member in the vehicle width direction. 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. On the floor portion behind the vehicle body from the two cross members 27, side frames that are reinforcing members in the longitudinal direction of the vehicle body, that is, a pair of side sills 20, a pair of floor side frames 22, and a pair of rear side frames 24 are provided.

  The pair of side sills 20 has a closed cross-sectional structure, and the front end portion thereof is No. The two cross members 27 are joined to both ends in the vehicle width direction. These side sills 20 are No. 3 cross member 28 and No. 3 No. 4 from almost the middle position of the cross member 29. The four inner side edges of the cross member 29 are curved inward in the vehicle width direction. The side sill 20 is connected to a lower end portion of a pillar 35 extending above the vehicle body, and an upper end portion of the pillar 35 is connected to a roof of the vehicle body.

  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. No. 4 connecting portion 29a and No. 4 cross member 29. 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.

As the reinforcing member in the vehicle width direction, the above-mentioned No. 1 cross member 26 and No. 1 2 In addition to the cross member 27, each of the No. 3 to No. No. 8 cross members 28 to 33 and closed cross-sectional structure No. 8 Nine cross members 34 are provided.
No. 3 cross member 28 is No.3. 2 provided on the vehicle body rear side of the cross member 27. 2 It extends linearly in the vehicle width direction in parallel with the cross member 27. 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 4 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, respectively, and a rigidity reducing portion 110 described later is provided in the vicinity thereof. 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, the reinforcing members in the longitudinal direction of the vehicle body are arranged in the longitudinal direction of the vehicle body at the edges on both sides in the vehicle width direction of the floor tunnel portion 50. 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 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 eight panel regions S1 to S8 surrounded by the frame members 20, 22, 27, 28, 36 and the bent portion 52, and among these regions, the panel region S5 is formed. Thru | or S8 is extended diagonally upward toward the vehicle body back with respect to panel area | region S1 thru | or S4.

  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. Further, the second floor panel 4 is formed with linear bead portions 56 on both sides along the curved portion 22a of the floor side frame 22 described above. This bead part 56 is No. No. 3 cross member 28 no. 4 extends to the cross member 29.
In the second floor panel 4, four panel regions S 9 to S 12 surrounded by the frame members 20, 22, 28, 29, the folded part 54 and the bead part 56 are formed.

  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.
On the third floor panel 6, four panel regions S13 to S16 surrounded by the frame members 22, 29, 30, 37 and the bead portion 58 are formed.

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.

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 edge portions of the four sides are joined to the frame members 24, 31, 32, respectively.
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 is transmitted to produce acoustic radiation.

  In 1st thru | or 3rd embodiment of this invention, a frame member is provided by providing a vibration reduction structure in each panel area | region S1-S4, S9, S12, S13-S16 of the 1st thru | or 3rd floor panels 2,4,6. The acoustic radiation radiated from those panel regions is suppressed by the vibration transmitted from.

  Here, the vibration reduction structure will be described. The vibration reducing structure is provided with a predetermined rigidity and / or a heavy part (high rigidity part, high weight part) and a predetermined rigidity and / or provided in a predetermined panel region of a floor panel surrounded by a frame member or the like. It is composed of low weight parts (low rigidity part, low weight part, peripheral part). The vibration energy of the vibration transmitted to the panel region is reduced by the rigidity difference between the high rigidity portion and the low rigidity portion and / or the weight difference between the high weight portion and the low weight portion. Alternatively, the vibration energy is reduced by virtue of the large vibration distortion caused by the concentrated vibration energy concentrated in the low weight part (peripheral part) and the damping ability of the material (for example, steel plate) constituting the floor panel itself (vibration reducing effect). ). In this way, the acoustic radiation radiated from each panel region is effectively reduced by the vibration reducing structure.

  Moreover, in 4th Embodiment of this invention, No. connected with the side sill 20 is shown. No. 4 cross member 29 is provided with a vibration transmission reducing structure, so Vibration transmitted to each of the panel regions S10, S11, S13, and S14 via the four cross members 29 is reduced. The above-described vibration reduction structure is also provided in the panel regions S10 and S11.

Here, the vibration transmission reducing structure will be described. The vibration transmission reducing structure has a predetermined low rigidity portion (rigidity reducing portion) in the vicinity of the connecting portion of the cross member connected so as to be orthogonal to the side frames such as the side sill 20, the floor side frame 22, and the rear side frame 24. Is provided. In the side frame, torsional vibration accompanied by deformation that tilts in the vehicle width direction and bending vibration accompanied by deformation that curves in the longitudinal direction are usually generated. As a result, the vibration transmitted from the side frame concentrates on the rigidity reducing portion. Therefore, vibration is less likely to be transmitted inward in the vehicle width direction from the rigidity reducing portion, and vibration transmitted from the cross member to each panel region is reduced. In this way, the acoustic radiation emitted from each panel area is reduced.
Note that the panel regions S5 to S8 and the fourth to eighth floor panels 8, 10, 12, 14, and 16 are configured by conventional panels.

First, the first embodiment of the present invention will be specifically described with reference to FIGS. 1 and 2. In the present embodiment, an opening 60 is formed in the panel regions S1, S4, S9, and S12 for removing the electrodeposition solution for cationic coating that is performed when the floor panel is manufactured. A high-rigidity portion (heavy-weight portion) 72 is formed with the lid member 66 fixed to the peripheral portion, and its peripheral portion 74 is a low-rigidity portion (low-weight portion) 74. Is surely obtained. Since the basic shape and arrangement of the vibration reduction structures provided in the panel regions S1, S4, S9, and S12 are the same, the description will be made mainly on the panel region S1.
FIG. 2 is an enlarged plan view (a) showing the panel region S1 according to the first embodiment of the present invention and a cross-sectional view (b) showing a cross-sectional structure in the longitudinal direction of the vehicle body viewed along the line II-II.

First, the configuration and shape of the panel regions S1, S4, S9, and S12 will be specifically described with reference to FIGS.
As shown in FIG. 1 and FIG. 2A, the panel regions S1 and S4 are formed by being surrounded by the frame members 20, 22, 27 and the bent portion 52. The two cross members 27 and the bent portion 52, and the side sill 20 and the floor side frame 22 are formed in a rectangular shape extending in parallel with each other. Here, as described above, the bent portion 52 is formed by bending the first floor panel 2 in a straight line, and the vibration generated in the panel region S5 or S8 adjacent to the vibration generated in the panel region S1 or S4. Plays a role as a vibration restricting part that restricts vibrations so that they are not coupled to each other.

  Further, as shown in FIG. 1, the panel regions S9 and S12 are formed in a substantially rectangular shape surrounded by the frame members 20, 28, 29 and the bead portion 56 formed along the curved portion 22a of the floor side frame 22. No. 3 cross member 28 and bead portion 56 extend in a straight line. Two sides formed by the four cross members and the side sill 20 have a shape including a curved portion 20 a formed by a curved portion of the side sill 20. The bead portion 56 serves as a vibration restricting portion that restricts the vibration region of the panel regions S9 and S12.

Next, the vibration reduction structure provided in the panel region S1 will be specifically described with reference to FIG. The vibration reduction structure provided in the panel regions S4, S9, and S12 is the same as that shown in FIG.
As shown in FIG. 2A, a circular opening 60 is formed in the panel region S <b> 1 at a substantially central portion that does not contact the frame members 20, 22, 27 and the bent portion 52. As shown in FIG. 2 (b), the opening 60 is composed of a stepped portion 62 that protrudes downward along the entire circumference and an inner hole 64, and the stepped portion 62 and the hole 64. Is formed by press molding. The step portion 62 includes an outer peripheral portion 62a extending in an oblique direction and an inner peripheral portion 62b extending in a horizontal direction, and is bent at portions indicated by a and b in FIG. 2 to enhance rigidity. A lid member 66 is fixed to the stepped portion 62 on the upper surface of the inner peripheral portion 62b.

  As shown in FIG. 2A, the lid member 66 is formed by pressing a steel plate into a circular shape having a size that substantially covers the opening 60. As shown in FIG. 2B, the plate thickness of the lid member 66 is larger than the plate thickness of the floor panel 2, and its rigidity and weight per unit area are higher than those of the floor panel 2.

  The hole 64 is for removing the electrodeposition liquid used when the floor panel is cationically coated, and is formed so that the stepped portion 62 protrudes downward, so that the electrodeposition liquid can be easily removed from the hole 64. It has become. The lid member 66 is firmly fixed by the adhesive 68 after the cationic coating so as not to be displaced relative to the floor panel. Further, a sealing material 70 is provided between the lid member 66 and the outer peripheral portion 62 a of the stepped portion 62 over the entire circumference. The adhesive 68 may also serve as the sealing material 70, and the lid member 66 may be fixed by welding.

In the present embodiment, the opening 60 and the lid member 66 formed in this way are configured as a high-rigidity part (high-weight part) 72, and the peripheral part 74 of the opening 60 and the lid member 66 is a low-rigidity part ( (Low weight part) 74. A boundary portion between the high-rigidity portion 72 and the low-rigidity portion 74 is a bent portion a of the step portion 62.
Instead of forming the stepped portion 62 in the opening 60, only the hole 64 through which the electrodeposition liquid is removed may be formed, and the lid member 66 may be fixed so as to cover the hole 64. In this case, the peripheral edge portion of the lid member 66 serves as a boundary portion between the high rigidity portion 72 and the low rigidity portion 74. Moreover, the hole 64 may be a positioning hole when the floor panel is press-molded.

As shown in FIG. 2B, the low-rigidity portion 74 is formed substantially flat, and a damping material 76 is attached to the entire area. As shown in FIG. 2A, the damping material 76 has an outer shape of a low-rigidity portion 74 that extends in a square shape so as to have a circular opening 76a along the outer peripheral edge a of the high-rigidity portion 72. It is formed into a combined sheet.
The low-rigidity portion 74 has a width, that is, a distance between the boundary portion a with the high-rigidity portion 72 and the frame members 20, 22, 27, or the folded portion 52 so that the rigidity of the low-rigidity portion 74 does not increase. It is formed to have a predetermined size.

  Here, the vibration damping material 76 is an asphalt vibration damping material (product name: damping sheet (manufactured by Hirotani Co., Ltd.)) having a specific gravity of about 1.7 and a hardness of about 6B in pencil hardness. The thickness is such that the rigidity of both of the low-rigidity parts 74 is lower than the rigidity of the high-rigidity part 72, that is, the rigidity of both the opening 60 and the lid member 66.

Next, a modification of the lid member 66 will be described with reference to FIG. FIG. 3 is a cross-sectional view (a) of the lid member according to the first modification and a plan view (b) of the lid member according to the second modification.
As shown in FIG. 3 (a), the lid member 66 according to the first modification has a U-shaped cross section, and a protruding portion 66a protruding downward along the entire circumference of the peripheral portion thereof, It is integrally formed by press molding. The protrusion 66a further enhances the rigidity of the lid member 66, particularly the rigidity against bending and twisting. The protruding portion 66a may be formed so as to protrude upward, and may be located at a part of the peripheral portion or the central portion as long as its rigidity is increased.
Next, as shown in FIG. 3 (b), the lid member 66 according to the second modified example has a plurality of beads 66b extending in the vertical and horizontal directions over the entire upper surface, which are integrally formed by press molding. The rigidity of the lid member 66 is further enhanced by the plurality of beads 66b.

Next, the function and effect of the first embodiment will be described.
In the panel regions S1, S4, S9, and S12 of the present embodiment, a high-rigidity portion 72 composed of a lid member 66 and an opening 60 having increased rigidity, and a low-resistance formed around the high-rigidity portion 72. Since the rigid portion 74 is provided, vibration energy concentrates on the low-rigidity portion 74 due to the difference in stiffness between the high-rigidity portion 72 and the low-rigidity portion 74.
The high-rigidity portion 72 is also configured as a high-weight portion 72 whose weight per unit area is increased by the lid member 66 as compared with the low-rigidity portion 74, and the low-rigidity portion 74 is a low-weight portion (peripheral portion) 74. Therefore, the vibration energy concentrates on the low weight part (peripheral part) 74 due to the difference in weight between the high weight part 72 and the low weight part 74.

Therefore, the vibration energy concentrated on the low rigidity portion (low weight portion) 74 is converted into thermal energy by the damping ability of the steel plates themselves constituting the floor panels 2 and 4, and as a result, the panel regions S1, S4, S9, and S12. The overall vibration energy is reduced and the acoustic radiation from those panel areas is reduced.
Furthermore, since the vibration damping material 76 is provided in the low rigidity portion (low weight portion) 74, vibration energy concentrated on the low rigidity portion (low weight portion) 74 is further reduced.

Next, functions and effects of the opening 60 and the lid member 66 constituting the high rigidity portion (heavy portion) 72 will be described.
In the present embodiment, the high-rigidity portion (high-weight portion) 72 is configured by an opening 60 for removing the cationic coating electrodeposition liquid, and a lid member 66 fixed to the opening 60. At the time of manufacture, the electrodeposition liquid can be easily removed, and then the rigidity and weight per unit area are greatly increased by fixing the lid member 66 to the opening 60. Can be easily formed.

  Further, since the lid member 66 can be formed separately from the floor panels 2 and 4, the rigidity can be easily increased. In this embodiment, since the plate thickness of the lid member 66 is higher than the plate thickness of the floor panels 2 and 4, it does not interfere with the exhaust pipes and auxiliary machinery, or the occupant's foot comfort is ensured. Therefore, the rigidity of the high-rigidity portion 72 can be greatly increased without projecting greatly upward or downward. Further, the lid member 66 formed separately can easily increase its weight per unit area, so that the weight can be easily increased greatly, and the weight difference between the high weight portion 72 and the low weight portion 74 can be reduced. Can also be increased.

Further, since the opening 60 is formed with a stepped portion 62 that is bent at the portions indicated by a and b in FIG. 2 and has increased rigidity, the rigidity of the high-rigidity portion 72 can be further increased. Further, since the step portion 62 protrudes downward, the electrodeposition liquid can easily escape from the hole 64 formed inward of the step portion 62.
In the present embodiment, the high-rigidity part (high-weight part) 72 and the low-rigidity part (low-weight part) 74 are formed so as to obtain both a rigidity difference and a weight difference. Depending on the shape and size of the lid, the shape, size, and material of the lid member 66, even if only a difference in rigidity or only a difference in weight can be obtained, the vibration energy should be concentrated on the low rigidity portion or the low weight portion. I can do it.

Next, in the lid member 66 according to the first modified example, since the protruding portion 66a protruding downward is formed along the entire circumference of the peripheral portion, the rigidity of the lid member 66, in particular, the rigidity against bending and twisting. As a result, the difference in rigidity between the high-rigidity portion 72 and the low-rigidity portion 74 can be further increased.
Similarly, in the lid member 66 according to the second modification example, a plurality of beads 66b extending vertically and horizontally are formed over the entire upper surface of the lid member 66, so that the rigidity of the lid member 66 is further increased. The rigidity difference from the rigid portion 74 can be further increased.
Further, the protrusion 66a and the bead 66b can be easily formed by press molding. Note that the protruding portion 66a and the bead 66b may be joined by bonding or the like.

  As described above, according to the present embodiment and the modification, even if there are restrictions on the vehicle body structure or processing such as the height, arrangement, and size as described above, the rigidity difference and / or the weight difference are reduced. The vibration energy in the panel region can be effectively reduced by greatly increasing it.

Next, a second embodiment of the present invention will be specifically described with reference to FIGS. In the present embodiment, the damping material 80 is attached to the panel regions S2 and S3 at a predetermined position and size, and the panel portion to which the damping material 80 is attached is formed as a high rigidity portion (high weight portion) 82. The peripheral portion 84 is formed as a low-rigidity portion (low-weight portion) 84, and the vibration reduction effect is surely obtained by the difference in rigidity and weight. Since the basic shape and arrangement of the vibration reduction structures provided in the panel areas S2 and S3 are the same, the description will be made mainly on the panel area S2.
FIG. 4 is an enlarged plan view (a) showing the panel region S2 according to the second embodiment of the present invention and a cross-sectional view (b) showing a cross-sectional structure in the vehicle width direction seen along the line IV-IV.

First, the configuration and shape of the panel regions S2 and S3 will be specifically described with reference to FIGS.
As shown in FIG. 1 and FIG. 4A, the panel regions S2 and S3 are formed by being surrounded by the frame members 22, 27, and 36 and the bent portion 52 which is a vibration restricting portion. 2 cross member 27 and bent portion 52, floor side frame 22 and No. 2 One tunnel side member 36 is formed in a rectangular shape extending in a straight line parallel to each other.

Next, the vibration reduction structure provided in the panel region S2 will be specifically described with reference to FIG. The vibration reduction structure provided in the panel region S3 is the same as that shown in FIG.
As shown in FIG. 4A, in the panel region S2, a substantially rectangular damping material 80 is provided at a substantially central portion not in contact with the frame members 22, 27, 36 and the bent portion 52. The vibration damping material 80 is formed in a substantially linear shape with its four sides extending in a slightly curved shape. The damping material 80 is a coating type damping material (aqueous acrylic emulsion) having a specific gravity of about 1.1 and a hardness of about 2H in pencil hardness (product name: NT damping coating W-250 (manufactured by Nippon Special Paint Co., Ltd.)). It is.

As shown in FIG. 4B, the panel region S2 is formed to be substantially flat, and the substantially central panel portion provided with the damping material 80 and the damping material 80 have a high rigidity. The rigid portion 82 is configured, and a substantially flat peripheral portion 84 around the high rigid portion 82 is configured as the low rigid portion 84. In particular, the coating type damping material 80 has a relatively high hardness of 2H in pencil hardness, and a large difference in rigidity from the low-rigidity portion 84 can be obtained. Further, due to the weight of the vibration damping material 80 itself, the weight per unit area of the vibration damping material 80 and the substantially central panel portion provided with the vibration damping material 80 is higher than that of the peripheral portion 84. The high-weight portion 82 is also configured, and the peripheral portion 84 is configured as the low-weight portion 84 so that a weight difference between the high-weight portion 82 and the low-weight portion (peripheral portion) 84 can be obtained.
The low-rigidity portion (low-weight portion) 84 has a width, that is, a distance between the boundary portion a with the high-rigidity portion (high-weight portion) 82 and the frame members 22, 27, 36, or the bent portion 52. The low rigidity portion 84 is formed to have a predetermined size that does not increase the rigidity.

  Next, a first modification of the present embodiment will be described. As a modification, the damping material 80 constituting the highly rigid portion (heavy portion) 82 may be an asphalt damping material. Asphalt vibration damping material has a specific gravity of about 1.7 and a pencil hardness of about 6B as described above, and has a higher specific gravity than a coating type vibration damping material. A large difference in weight from the portion 84 is obtained.

Next, a second modification of the present embodiment will be described with reference to FIG.
As shown in FIG. 5, in this modified example, as described above, the coating-type damping material 80 is provided in the substantially central portion of the panel region S2 to form the high-rigidity portion (high-weight portion) 82, and further, the low-weight portion. An asphalt vibration damping material 86 is provided on the portion (peripheral portion) 84. The specific gravity and hardness of the coating type damping material and the asphalt damping material are as described above.
In this modification, the vibration damping material 80 constituting the high rigidity portion (high weight portion) 82 is a coating type vibration damping material having a high hardness of 2H in pencil hardness, and is provided in the low rigidity portion (low weight portion) 84. The damping material 86 is an asphalt damping material having a pencil hardness of 6B, which is low, so that a difference in rigidity between the high rigidity portion 82 and the low rigidity portion 84 can be obtained.

  On the other hand, the specific gravity of the asphalt vibration damping material 86 is larger than that of the coating type vibration damping material 80. Therefore, in this modified example, as shown in FIG. 5B, the thickness of the coating type damping material 80 provided in the high rigidity portion (high weight portion) 82 is provided in the low rigidity portion (low weight portion) 84. The weight per unit area of the high-rigidity portion (high-weight portion) 82 is made larger than the thickness of the asphalt-based vibration-damping material 86 and the low-rigidity portion (low-weight portion) 84 provided with the asphalt-based vibration-damping material 86. The weight difference is also obtained by increasing the weight per unit area.

Next, the function and effect of the second embodiment will be described.
In the panel regions S2 and S3 of the present embodiment, a high-rigidity portion 82 provided with a vibration damping material 80 and increased in rigidity and a low-rigidity portion 84 formed around the high-rigidity portion 82 are provided. Therefore, vibration energy is concentrated on the low rigidity portion 84 due to the difference in rigidity between the high rigidity portion 82 and the low rigidity portion 84.
Further, the high-rigidity portion 82 is also configured as a high-weight portion 82 in which the weight per unit area is increased by the damping material 80 as compared with the peripheral portion 84. The vibration energy concentrates on the low weight part (peripheral part) 84 due to the difference in weight.

  Therefore, the vibration energy concentrated on the low rigidity portion (low weight portion) 84 is converted into thermal energy by the damping ability of the steel plates themselves constituting the floor panels 2 and 4, and as a result, the vibration energy of the entire panel regions S2 and S3. Are reduced to reduce acoustic radiation from those panel areas.

Next, the effect of the damping material 80 which comprises the highly rigid part (high weight part) 82 is demonstrated.
In the panel regions S2 and S3 of the present embodiment, the high-rigidity portion (heavy-weight portion) 72 is formed by being provided with a coating-type damping material 80 having a relatively high hardness of 2H in pencil hardness. A large difference in rigidity from the rigid portion 84 is obtained. In addition, the weight of the damping material 80 itself forms a high weight portion 82 whose weight per unit area is larger than that of the low weight portion 84, so that the weight difference from the low weight portion (peripheral portion) 84 is also increased. Can be obtained. Further, the vibration energy of the panel regions S2 and S3 is reduced by the damping capacity of the damping material 80 itself.

  Next, in the first modified example, the damping material 80 constituting the high-rigidity portion (heavy-weight portion) 82 is formed of an asphalt-based damping material having a specific gravity higher than that of the coating-type damping material. It is easy to obtain a large weight difference from the portion (low weight portion) 84, and vibration energy can be concentrated on the low rigidity portion (low weight portion) 84 mainly due to the weight difference.

  Next, in the panel region S2 according to the second modified example, the high-rigidity portion (high-weight portion) 82 is formed of a coating-type damping material 80 (pencil hardness 2H) having a relatively high hardness, and the peripheral portion 84 has a low Since the asphalt vibration damping material 86 (pencil hardness 6B) having a relatively low hardness is provided in the rigid portion (low weight portion) 84, vibration is caused by the vibration reducing effect due to the rigidity difference between the high rigid portion 82 and the low rigid portion 84. Energy can be reduced. Furthermore, vibration energy can be further reduced by the damping capacity of the coating-type damping material 80 and the asphalt damping material 86 itself.

  On the other hand, the specific gravity (= about 1.1) of the coating type damping material 80 is larger than the specific gravity (= about 1.7) of the asphalt type damping material 86, but the coating that forms the high rigidity portion (high weight portion) 82. Since the thickness of the mold damping material 80 is larger than the thickness of the asphalt damping material 86 provided in the low rigidity portion (low weight portion) 84, the unit area of the high rigidity portion (high weight portion) 82 The hit weight can be increased from the weight per unit area of the low-rigidity portion (low-weight portion) 84 provided with the asphalt-based vibration damping material 86, and the high-rigidity portion (high-weight portion) 82 and the asphalt-based damping can be increased. The vibration energy can also be reduced by the vibration reduction effect due to the weight difference from the low rigidity portion (low weight portion) 84 provided with the vibration member 86.

As described above, in the present embodiment and the modification thereof, the vibration damping material 80 and / or the vibration damping material 86 are provided to provide the high rigidity portion (high weight portion) 82 and the low rigidity portion (low weight portion (peripheral portion)). By forming 84, the vibration energy of the panel regions S2 and S3 can be greatly reduced by the vibration reduction effect due to the rigidity difference and the weight difference and the vibration reduction due to the damping capacity of the damping materials 80 and 86 themselves.
Therefore, even if there are restrictions on the vehicle structure or processing such as the height, arrangement, and size as described above, the high weight portion 82 having a weight increased more than the low weight portion (peripheral portion) 84 is formed. Therefore, vibration energy in the panel region can be effectively reduced.

Next, a third embodiment of the present invention will be specifically described with reference to FIGS. In the present embodiment, the high-rigidity portion 92 and the low-rigidity portion 94 are formed as vibration reducing structures in the panel regions S13 to S16, respectively, and the high-rigidity portion 92 is formed in a substantially rectangular shape having sides extending in a predetermined curved shape. Thus, a vibration reduction effect can be reliably obtained. Here, since the basic shape and arrangement of the vibration reduction structures provided in the panel regions S13 and S14 or the panel regions S15 and S16 are the same, the description will focus on the panel regions S13 and S15.
FIG. 6 is an enlarged plan view (a) showing a panel region S13 according to the third embodiment of the present invention and a cross-sectional view (b) showing a cross-sectional structure in the longitudinal direction of the vehicle body viewed along the line VI-VI. FIG. 7 is an enlarged plan view (a) showing the panel region S15 and a cross-sectional view (b) showing a cross-sectional structure in the longitudinal direction of the vehicle body viewed along the line VII-VII.

First, the configuration and shape of the panel regions S13 to S16 will be specifically described with reference to FIG. 1, FIG. 6, and FIG.
As shown in FIGS. 1 and 6A, the panel regions S13 and S14 are formed by being surrounded by the frame members 22, 29, and 37 and the bead portion 58, and each of the frame members 22, 29, and 37 and the bead. Each of the portions 58 extends linearly, and The four cross member 29 and the bead portion 58 are formed in a substantially rectangular shape extending in parallel with each other.
As shown in FIGS. 1 and 7A, the panel regions S15 and S16 are formed by being surrounded by the frame members 22, 37, and 30 and the bead portion 58, and each of the frame members 22, 30, 37, and the bead. Each of the portions 58 extends linearly, and the bead portion 58 and the No. The five cross members 30 are formed in a substantially rectangular shape extending in parallel with each other.

  Here, the floor side frame 22 is No. 4 cross member 29 and no. 5 is bent at the connecting portions 29a and 30a with the cross member 30 (folded portions 22b and 22c). 4 cross member 29 and no. It is formed so as to extend linearly between the five cross members 30. Further, the bead portion 58 serves as a vibration restricting portion that restricts vibration so that vibration generated in the panel region S13 or S14 and vibration generated in the adjacent panel region S15 or S16 are not coupled to each other.

Next, the vibration reduction structure provided in the panel region S13 will be specifically described with reference to FIG. The vibration reducing structure provided in the panel region S14 is the same as that shown in FIG.
As shown in FIG. 6A, in the panel region S13, a substantially rectangular high-rigidity portion 92 is formed at a substantially central portion not in contact with the frame members 22, 29, 37 and the bead portion 58. Around the rigid portion 92, a low-rigidity portion 94 extending in a square shape is formed. As shown in FIG. 6B, the high-rigidity portion 92 is formed by projecting the floor panel itself upward of the vehicle body, and the cross-sectional shape thereof is substantially flat at the center, and the periphery thereof is the low-rigidity portion 94. It extends in a straight line so as to stand up at a discontinuous angle. On the other hand, the low rigidity portion 94 is formed substantially flat.

As shown in FIG. 6 (a), the high-rigidity portion 92 has two long sides 92a extending in the vehicle width direction and two short sides 92b extending in the vehicle body front-rear direction. It is formed so as to bulge in the direction and extend in a continuous curved shape. As will be described later, each side 92a, 94a of the high-rigidity portion 92 bulges outward and extends in a curved shape having a continuous curvature, whereby each side that is a boundary portion with the low-rigidity portion 94 The rigidity is changed discontinuously at 92a and 92b, and the difference in rigidity is more reliably obtained.
In the present embodiment, each side 92a, 92b extends in an arc shape, and the curvature radius of each long side 92a is formed to be smaller than the curvature radius of each short side 92b. The low-rigidity portion 94 is formed to extend with a predetermined width so that the rigidity of the low-rigidity portion 94 does not increase, as in the first and second embodiments described above.

  As shown in FIGS. 6A and 6B, the low-rigidity portion 94 is attached with an asphalt vibration damping material 96 over the entire area in the same manner as the panel region S1 described above. The high-rigidity portion 92 is formed in a sheet shape having a shape matching the outer shape of the low-rigidity portion 94 extending in a square shape so as to have a substantially rectangular opening 96a along the outer peripheral edges 92a and 92b.

  Next, as shown in FIGS. 6A and 6B, a bracket 98 is provided in the space formed by protruding the high-rigidity portion 92, and the auxiliary device is installed on the upper surface of the high-rigidity portion 92 by the bracket 98. A class 100 is attached. Examples of the auxiliary machines include a CD changer, a navigation unit, a CPU device, various power supplies, a console box, harnesses, and an air conditioner. In the present embodiment, the high-rigidity portion 92 to which the auxiliary machinery 100 is attached is configured as a high-weight portion 92 in which the weight per unit area is larger than the low-rigidity portion 94 due to the weight of the auxiliary machinery 100 itself. The low-rigidity portion 94 is configured as the low-weight portion 94, and a weight difference between the high-weight portion 92 and the low-weight portion (peripheral portion) 94 can be obtained. Also, a weight difference is obtained by the weight of the bracket 98 itself. Furthermore, by attaching the bracket 98 and the auxiliary machinery 100, the rigidity of the high-rigidity portion 92 is further increased.

Next, the vibration reduction structure provided in the panel region S15 will be specifically described with reference to FIG. The vibration reducing structure provided in the panel region S16 is the same as that shown in FIG.
As shown in FIG. 7, a substantially rectangular high-rigidity portion 92 and a low-rigidity portion 94 extending in a U shape around the high-rigidity portion 92 are formed in the panel region S15. As shown in FIG. 7B, the high-rigidity portion 92 is formed by protruding the floor panel itself downward from the vehicle body, and its cross-sectional shape is a dome shape whose curved surface height changes continuously. The high-rigidity portion 92 may be formed so as to protrude upward from the vehicle body. On the other hand, the low rigidity portion 94 is formed substantially flat.

  As shown in FIG. 7 (a), the high-rigidity portion 92, like the high-rigidity portion 92 of the panel region S13 described above, has its sides 92a and 94b each extending in an arc shape that swells outward, and has a long side. The radius of curvature of 92a is smaller than the radius of curvature of the short side 92b. In this panel region S15, the high-rigidity portion 92 is No. 2 at a substantially middle portion of the long side 92a on the vehicle body rear side. 5 is in contact with the cross member 30. The high rigidity portion 92 is in contact with the high rigidity portion 92. A reinforcing bead 102 extending from the cross member 30 side toward the low rigidity portion 94 side is formed, and the rigidity of the high rigidity portion 92 in the longitudinal direction of the vehicle body is enhanced. The low-rigidity portion 94 extends with a predetermined width as in the first and second embodiments described above.

  As shown in FIGS. 7A and 7B, the low-rigidity portion 94 is attached with an asphalt vibration damping material 96 over the entire area in the same manner as the panel region S1 described above. The sheet is formed in a sheet shape that matches the outer shape of the low-rigidity portion 94 extending in a U-shape so as to have a substantially rectangular opening 96 a along the outer peripheral edge of the high-rigidity portion 92.

Next, the function and effect of the third embodiment will be described.
In the panel regions S13 to S16 of the present embodiment, the high rigidity portion 92 which is formed by protruding the floor panel itself upward or downward of the vehicle body and has increased rigidity, and the low rigidity formed around the high rigidity portion 92. Since the portion 94 is provided, vibration energy is concentrated on the low-rigidity portion 94 due to a difference in rigidity between the high-rigidity portion 92 and the low-rigidity portion 94.
Further, in the panel regions S13 and S14, the auxiliary machinery 100 is attached to the high-rigidity portion 92, so that the rigidity of the high-rigidity portion 92 is further increased by the auxiliary machinery 100, and a larger rigidity difference is obtained. It is done.

  Further, the high-rigidity portion 92 to which the auxiliary machinery 100 is attached is also a high-weight portion 92 in which the weight per unit area is increased from the peripheral portion (low-weight portion) 94 due to the weight of the auxiliary machinery 100 itself. Since it is configured, a weight difference from the low weight portion 94 formed around the high weight portion 92 is obtained. Further, the weight difference is also obtained by the weight of the bracket 98 itself for attaching the auxiliary machinery 100. As a result, the vibration energy is more concentrated on the low rigidity portion (low weight portion) 94 due to such a weight difference.

Therefore, the vibration energy concentrated on the low rigidity portion (low weight portion) 94 is converted into heat energy by the damping ability of the steel plates themselves constituting the floor panels 2 and 4, and as a result, the vibration of each panel region S 13 to S 16 as a whole. Energy is reduced to reduce acoustic radiation from those panel areas.
Furthermore, since the vibration damping material 96 is provided in the low rigidity portion (low weight portion) 94, vibration energy concentrated on the low rigidity portion (low weight portion) 94 is further reduced.

Next, the effect of the shape and arrangement of the high-rigidity part (heavy part) 92 will be described.
In the present embodiment, each side 92a, 94a of the high-rigidity portion 92 is formed so as to bulge outward and have a curved shape with continuous curvature. The rigidity changes discontinuously at the sides 92a and 92b, and the rigidity difference between the high-rigidity portion 92 and the low-rigidity portion 94 can be increased. As a result, for example, the projecting height of the high-rigidity portion 92 can be reduced, and vibrations can be made while not interfering with exhaust pipes, auxiliary machinery, etc., or ensuring the comfort of the occupants' feet. A reduction effect can be obtained with certainty. Such operational effects will be described more specifically below.

Here, first, when the floor panel is integrally formed by press working to form a highly rigid portion that protrudes upward or downward, if the protruding height of the highly rigid portion is suppressed to a certain height, It may be difficult to form the shape with high accuracy. That is, when press forming, the steel plate is stretched and plastically deformed to form a highly rigid portion. For example, the protruding height is suppressed to a certain height and each side extends in a completely linear shape. If formed in this way, it may be difficult to clearly form a linear broken line at the boundary portion (each side of the high rigidity portion) between the low rigidity portion and the high rigidity portion.
In this case, for example, as shown in FIG. 8 (a), the rigidity gradually changes from the low rigidity part to the high rigidity part with the boundary part as a boundary, and it becomes difficult to obtain a large rigidity difference. As a result, it becomes difficult for the vibration energy to concentrate on the low rigidity portion, and the above-described vibration reduction effect cannot be obtained effectively.

On the other hand, when each side 92a, 94a of the high-rigidity portion 92 is formed so as to bulge outward and extend in a curved shape with a continuous curvature as in the present embodiment, press molding is facilitated. That is, when the boundary portion extends in a curved shape in press molding, it becomes easy to form a polygonal line that clearly extends in a curved shape at the boundary portion (each side of the high rigidity portion) between the low rigidity portion and the high rigidity portion.
In this case, as shown in FIG. 8B, the rigidity is easily changed discontinuously at each side 92a and 92b which is a boundary part with the low-rigidity part 94, and a large rigidity difference is easily obtained. . Further, the high rigidity portion 92 is greatly enhanced in rigidity, particularly torsional rigidity. As a result, vibration energy can be reliably concentrated on the low rigidity portion, and a vibration reduction effect can be obtained with certainty.
Furthermore, in this embodiment, since each side 92a, 92b of the high-rigidity portion 92 extends in an arc shape, the rigidity is more reliably changed discontinuously at the boundary portion, and the rigidity difference is reliably increased. I can do it.

  Here, in press molding, the shorter the length of the side that is the boundary portion, or the longer the side extends in a curved shape and the smaller the radius of curvature, the easier it is to obtain the molding accuracy. In the present embodiment, since the radius of curvature of each long side 92a is formed to be smaller than the radius of curvature of each short side 92b, the rigidity of the long side 92a is more reliably discontinuous at the boundary portion. Further, the rigidity difference can be surely increased.

  On the other hand, if the radius of curvature of the long side 92a extending in an arc shape is reduced, the long side 92a may protrude toward the low-rigidity portion 92 compared to the short side 92b, and the rigidity of the low-rigidity portion 94 may be increased. However, since the area of the low-rigidity portion 94 extending around the long side 92a is relatively larger than the portion of the low-rigidity portion 94 extending around the short side 92b, the low-rigidity portion extending around the long side 92a. Without greatly increasing the rigidity of the portion 94, it is possible to prevent the range where vibration energy is concentrated from being greatly reduced.

  If the high-rigidity portion is formed in a circular shape or an elliptical shape, the rigidity of the high-rigidity portion is discontinuously changed at the boundary portion and the rigidity is easily increased. On the other hand, the rigidity of the low-rigidity portion is easily increased. In the present embodiment, each side 92a, 94a of the high-rigidity portion 92 is formed so as to bulge outward and have a curved shape with a continuous curvature, and the high-rigidity portion 92 is formed in a substantially rectangular shape. It is possible to prevent the rigidity of the low-rigidity portion (low-weight portion) 94 extending in a square shape or a U-shape around the boundary portion from changing discontinuously at the boundary portion and not greatly increasing. Furthermore, since the low-rigidity portion 94 is formed so as to extend with a predetermined width so that its rigidity does not increase, vibration energy can be reliably concentrated on the low-rigidity portion (low-weight portion) 94.

  Next, in the panel regions S15 and S16, the high-rigidity portion 92 is No. Since the five cross members 30 are formed in contact with each other, the rigidity of the high rigidity portion 92 can be greatly increased. Therefore, for example, even when the area of the panel area is relatively small and the rigidity of the panel area itself is relatively high, the rigidity of the high-rigidity part can be greatly increased and the rigidity difference from the low-rigidity part can be increased. The vibration energy can be largely concentrated on the low rigidity portion 62.

Next, the effect of the shape of the damping material 96 will be described.
Since the damping material 96 has substantially rectangular openings 96a along the outer peripheral edges 92a and 92b of the high-rigidity portion 92, the outer peripheral edges 92a and 92b of the high-rigidity portion 92 and the damping material opening 96a. With this, positioning in the front-rear direction and the vehicle width direction is facilitated, and the manufacturing cost can be reduced. Further, since the positioning accuracy is improved, the damping material 96 is not provided across both the high-rigidity portion 92 and the low-rigidity portion 94, and the rigidity of the low-rigidity portion 94 and the damping material 96 is prevented from increasing. I can do it.

  As described above, according to the present embodiment, the high rigidity portion 92 and the low rigidity portion 94 can be provided even when there are restrictions on the vehicle body structure or processing such as the height, arrangement, and size as described above. By greatly increasing the difference in rigidity and / or the weight difference between the high weight portion 92 and the low weight portion 94, vibration energy in the panel region can be effectively reduced.

Next, the fourth embodiment of the present invention will be specifically described with reference to FIGS. In this embodiment, no. By providing a vibration transmission reducing structure in the vicinity of the side sill 20 of the 4 cross member 29, the side sill 20 is connected to Vibration transmitted to the panel regions S10, S11, S13, and S14 via the four cross members 29 is reduced, and acoustic radiation from these panel regions is reduced. In addition, in the panel regions S10 and S11, the vibration transmission amount is reduced. 9 A high rigidity portion is provided so as to contact the cross member 29. While preventing large vibrations from being transmitted from the four cross members 29 to the panel regions S10 and S11, the rigidity of the high-rigidity portion is greatly increased, and the same vibration reduction effect as the panel regions S15 and S16 described above can be obtained. It is like that.
FIG. 9 is a diagram illustrating No. 4 according to the fourth embodiment of the present invention. FIG. 4 is a partially enlarged front view (a) seen from the front side of the vehicle body and a partially enlarged plan view (b) seen from the upper side of the vehicle body, showing the four cross members together with the side sill and pillar. FIG. 4 is an enlarged view of the vicinity of the connecting portion of the cross member 29 with the side sill 20 on the right side in the vehicle width direction.

First, referring to FIG. The configuration and shape of the vibration transmission reducing structure provided on the four cross member 29 will be specifically described.
As shown in FIGS. 9A and 9B, a pillar 35 is connected to the side sill 20. The four cross members 29 are connected to the side sills 20 in the vicinity of the pillars 35 at both ends in the vehicle width direction (see FIG. 1). No. The four cross members 29 are connected to the side sill 20 so as to be substantially orthogonal.

  No. The 4-cross member 29 is provided with a rigidity reducing portion 110 in the vicinity of the connecting portion 29b with the side sill 20 at both ends in the vehicle width direction (see FIG. 1). This rigidity reduction part 110 is No. Four cross members 29 on the vehicle body front side surface (front surface) 29c and vehicle body rear side surface (rear surface) 29d, each having a circular arc-shaped recess 112c, 112d extending from the upper end to the lower end in the vehicle body vertical direction, and the vehicle body lower surface (Lower surface) 29e is constituted by a concave portion 112e having an arcuate cross section extending from the front end to the rear end in the vehicle longitudinal direction.

  The recesses 112c to 112e are connected to each other so that the recess 112c on the front surface and the recess 112e on the lower surface extend continuously, and further, so that the recess 112e on the lower surface and the recess 112d on the rear surface extend continuously. It is connected and extends in a U shape across its front surface 29c, lower surface 29e and rear surface 29d. No. The second floor panel 4 is joined to the upper surface (flange) 29 f of the four cross member 29. In FIG. 9B, the second floor panel 4 is omitted.

The rigidity reduction unit 110 has a rigidity in the vehicle width direction of No. 4 is lower than the rigidity of the other part of the cross member 29. The vibration transmitted to the four cross member 29 concentrates on the rigidity reducing portion 110 (recessed portion 112) and is less likely to be transmitted inward in the vehicle width direction from the rigidity reducing portion 110.
In addition, the coating-type damping material 116 is intensively arranged in the concave portions 112c to e in an inner space having an arcuate cross section, and the damping material 116 attenuates the vibration concentrated on the concave portion 112. At the same time, vibration is more difficult to be transmitted inward in the vehicle width direction from the recess 112. The specific gravity and hardness of the coating type damping material are as described above. An asphalt vibration damping material may be provided.

Next, as shown in FIG. The 4 cross member 29 has a small vertical height at a portion 29 h in the vicinity of the connecting portion with the side sill 20. That is, the closed cross-sectional area of the vicinity portion 29h is smaller than the closed cross-sectional area of the other portion so that the rigidity is lower than that of the other portion. It is difficult for vibration to be transmitted to the four cross members 29.
Thus, no. The rigidity of the vicinity of the connecting part of the 4 cross member 29 with the side sill 20 is determined by the rigidity reducing part 110 and the vicinity part 29h having a small closed cross-sectional area, so that other cross members, for example, No. 4 It is smaller than the rigidity of the vicinity of the connecting part of the three cross member 28 to the side sill 20 and the floor side frame 22.

  As a modification, as shown in FIG. 10, the concave portion 112 of the rigidity reducing portion 110 may be made wider and the concave portion 112 may be in contact with the side sill 20. In this modification, the recess 112 has a U-shaped cross section. In this way, the rigidity of the rigidity reducing unit 110 can be further reduced.

  Next, although not shown, no. The connecting portion 29a between the 4 cross member 29 and the floor side frame 22 has a joint area relatively lower than that of the other cross members, so that vibration from the floor side frame 22 is not easily transmitted. In addition, the rigidity reduction part 110 may be provided in the vehicle width direction inner side vicinity of the connection part of the floor side frame 22, and may be provided in another cross member.

Next, the configuration, shape, and vibration reducing structure of the panel regions S10 and S11 will be specifically described with reference to FIGS.
FIG. 11 shows a No. 4 according to the fourth embodiment of the present invention. FIG. 12 is an enlarged plan view (a) showing a four cross member and a panel region S10, and a cross-sectional view (b) showing a cross-sectional structure in the longitudinal direction of the vehicle body viewed along the line XI-XI. FIG. No. 4 according to the fourth embodiment. FIG. 4 is an enlarged plan view (a) showing a 4-cross member and a panel region S11, and a cross-sectional view (b) showing a cross-sectional structure in the longitudinal direction of the vehicle body viewed along the line XII-XII.

  First, as shown in FIGS. 11 (a) and 12 (a), the panel regions S10 and S11 are surrounded by frame members 28 and 29, a bent portion 54, and a bead portion 56 that extend linearly, respectively. No. 3 cross member 28 and no. The four cross members 29 are formed in a substantially rectangular shape extending in parallel with each other. Here, each of the bent portion 54 and the bead portion 56 serves as a vibration restricting portion that restricts the vibration region of the panel region S10.

  As shown in FIG. 11A, a rectangular high-rigidity portion 92 and a low-rigidity portion 94 extending in a U shape around the high-rigidity portion 92 are formed in the panel region S10. As shown in FIG. 11B, the high-rigidity portion 92 is formed by projecting the floor panel itself upward of the vehicle body, and its cross-sectional shape is substantially trapezoidal. On the other hand, the low-rigidity portion 94 is formed substantially flat, and the asphalt vibration damping material 96 is attached to the entire area in the same manner as in the first and third embodiments described above.

  As shown in FIG. 11A, the high-rigidity portion 92 has three sides extending linearly, and the remaining one side is No. 4 is in contact with the cross member 29. This No. As described above, the vibration from the side sill 20 is difficult to be transmitted to the four cross member 29 by the rigidity reducing portion 110. The low-rigidity portion 94 is formed to extend with a predetermined width so that the rigidity of the low-rigidity portion 94 does not increase, as in the first to third embodiments described above.

  Further, as shown in FIGS. 11A and 11B, a bracket 98 is provided in a space formed by protruding the high-rigidity portion 92, and the auxiliary machinery 100 is provided on the upper surface of the high-rigidity portion 92 by this bracket. Is to be provided. One side of this bracket is No. It is fixed to the 4 cross member 29. The high-rigidity portion 92 to which the auxiliary machinery 100 is attached is also configured as a high-weight portion 92, similar to the above-described panel regions S13 and S14.

  Next, as shown in FIG. 12A, the panel region S11 is formed with a substantially rectangular high-rigidity portion 92 that is formed in a substantially linear shape with each side extending slightly in a curved shape. . The high-rigidity portion 92 has one side on the rear side of the vehicle body and one side on the inner side in the vehicle width direction adjacent to each other at a substantially intermediate portion. 4 is in contact with the cross member 29 or the bent portion 54. A low-rigidity portion 94 extending in an L shape is formed around the high-rigidity portion 92, and extends with a predetermined width so that the rigidity is not increased, as in the first to third embodiments. .

  As shown in FIG. 12B, the high-rigidity portion 92 is formed by protruding the floor panel itself downward from the vehicle body, and its cross-sectional shape is a dome shape whose curved surface height changes continuously. In addition, you may form each high-rigidity part 92 so that it may protrude above a vehicle body. On the other hand, the low-rigidity portion 94 is formed substantially flat, and the asphalt vibration damping material 96 is attached to the entire area in the same manner as in the first and third embodiments described above.

Next, the function and effect of the fourth embodiment will be described.
First, no. The effect of the rigidity reduction part 110 provided in the 4 cross member 29 is demonstrated.
No. of this embodiment. No. 4 cross member 29 is connected to the side sill 20 in the vicinity of the connecting portion 29a. Since the rigidity reducing portion 110 having a lower rigidity than the other parts of the 4 cross member 29 is provided, the side sill 20 is changed to No. 4. The vibration transmitted to the four cross members 29 can be concentrated on the rigidity reducing portion 110 to prevent the vibration from being greatly transmitted inward in the vehicle width direction from the rigidity reducing portion 110.

  Specifically, for example, when the side sill 20 is torsionally oscillated around the longitudinal axis (vehicle longitudinal direction), or when the side sill 20 is bent and oscillated in the vehicle vertical direction or the vehicle width direction with respect to the longitudinal direction, No . The vibration with such torsion and bending force is transmitted to the 4 cross member 29. As described above, the rigidity reducing unit 110 has a rigidity in the vehicle width direction of No. Since the rigidity of the other part of the 4 cross member 29 is lower than that, vibrations with such torsional and bending forces are transmitted to facilitate deformation. Therefore, the vibration transmitted from the side sill 20 is concentrated on the rigidity reducing portion 110 that is easily deformed in this way, and it is possible to prevent the vibration from being greatly transmitted inward in the vehicle width direction from the rigidity reducing portion 110. . As a result, no. The vibration transmitted to each of the panel regions S10, S11, S13, and S14 via the four cross members 29 can be reduced, and acoustic radiation from those panel regions can be reduced.

Hereinafter, the operation of the rigidity reducing unit 110 will be described more specifically with reference to FIG.
First, in the rigidity reducing portion 110, No. The main function and effect of the recess 112e provided on the lower surface 29e of the four cross member 29 will be described.
As shown in FIG. 13 (a), for example, if a force as indicated by A in the figure is applied to the side sill 20 by pushing up from the road surface to the suspension, the side sill 20 is The bending vibration accompanied by the deformation that curves in the direction is excited, and the bending vibration of the side sill causes the upper body 122 (see FIG. 13B) including the pillar 35 and the roof 120 to have its vibration. A vibration accompanied by a deformation that twists the whole is excited.

When such vibration is excited in the upper body 122, the pillar 35 vibrates with deformation that curves in the vehicle width direction as shown in FIG. 13B, for example. For example, when a box having a closed cross-sectional structure is twisted, its side surface is bent and deformed. Since these pillars 35 are connected to the side sill 20, as shown by B in the figure, the side sill 20 vibrates with deformation that is inclined in the vehicle width direction. A vibration that causes bending deformation as indicated by a virtual line C in the drawing is transmitted to the 4 cross member 29.
Such vibration that causes bending deformation concentrates on the rigidity reducing portion 110, and among the concave portions 112 that are the rigidity reducing portion 110, mainly the concave portions 112e provided on the lower surface 29e are particularly greatly deformed. As a result, the vibration transmitted inward in the vehicle width direction from the rigidity reducing portion 110 is reduced, and the bending vibration is reduced as indicated by a solid line D in the figure.

  In particular, the rigidity reducing portion 110 is a No. 1 member connected to the side sill 20 in the vicinity of the pillar 35 among the plurality of cross members. Since the four cross members 29 are formed, even if the side sill 20 is deformed to be inclined in the vehicle width direction due to the bending vibration of the pillar 35 caused by the torsional vibration of the upper body 122, it is effective. , No. It is possible to prevent vibrations from being greatly transmitted to the inside of the four cross members 29 in the vehicle width direction. On the other hand, other cross members such as No. Since the 3 cross member 28 is not provided with a rigidity reducing portion, the rigidity of the entire vehicle body can be ensured.

Next, in the rigidity reducing portion 110, No. The main effects of the recesses 112c and 112d provided on the front and rear surfaces 29c and 29d of the four cross member 29 will be described.
For example, when a lateral force is applied to the suspension from the road surface, the side sill 20 is excited with vibration accompanied by deformation that curves in the vehicle width direction with respect to the longitudinal direction. And, by such bending vibration in the vehicle width direction, No. Vibration that causes bending deformation in the direction indicated by E in FIG. 13A is transmitted to the four cross member 29.
Such bending deformation concentrates on the rigidity reducing unit 110, and the recesses 112c and 112d provided mainly on the front surface 29c and the rear surface 29d among the recesses 112 that are the rigidity reducing unit 110 are particularly large. Deform. As a result, vibration transmitted from the rigidity reducing portion 110 inward in the vehicle width direction is reduced.

Next, the effect of the recessed parts 112c-e extended in U shape among the rigidity reduction parts 110 is demonstrated.
When the side sill 20 is vibrated with a deformation that curves in the vertical direction of the vehicle body with respect to its longitudinal direction, for example, by a force as indicated by A in the figure, Vibration that causes torsional deformation in the direction indicated by F in FIG. 13A is transmitted to the four cross member 29.
Such vibration that causes torsional deformation concentrates on the rigidity reducing portion 110 and deforms so that the concave portions 112c to 112d extending in a U-shape are twisted substantially uniformly. As a result, vibration transmitted from the rigidity reducing portion 110 inward in the vehicle width direction is reduced.

Next, the effect of the damping material 116 provided in the rigidity reduction part 110 is demonstrated.
In the present embodiment, since the damping material 116 is intensively disposed in the inner space of the concave portion 112 having a circular arc shape, the vibration concentrated on the concave portion 112 can be attenuated. It is possible to more reliably prevent vibrations from being greatly transmitted inward in the vehicle width direction.

Next, the effect of the rigidity reduction part 110 by a modification is demonstrated.
Since the concave portion 112 of the present modification shown in FIG. 10 has a large width, the rigidity in the vehicle width direction can be further reduced, and as a result, vibration is greatly transmitted inward in the vehicle width direction. This can be prevented more reliably. Moreover, since the recessed part 112 by a modification is formed so that the side sill 20 may be contact | connected, the vibration accompanying various deformation | transformation of the side sill 20, such as a bending and a twist, can be more reliably concentrated on the recessed part 112. FIG. Further, since the recess 112 according to the modification has a U-shaped cross section, the rigidity thereof can be further reduced with respect to vibration transmitted from the side sill 20.

  As described above, according to the present embodiment and the modification, the frame member is provided with the rigidity reducing portion even when there are restrictions on the vehicle body structure or processing such as the height, arrangement, and size as described above. Therefore, vibration energy in the panel region can be effectively reduced. For example, if the frame member is provided with a rigidity reduction portion, it is transmitted to the floor panel without being restricted by interference with exhaust pipes, auxiliary equipment, etc., or without deteriorating the occupant's foot comfort. Vibration can be reduced.

Next, the effect of the vibration reduction structure provided in the panel regions S10 and S11 will be described.
In this embodiment, the frame member 29 is provided with a rigidity reducing portion 110 that is a vibration transmission reducing structure to reduce vibration transmitted to the panel region, and the high rigidity portion 92 that is a vibration reducing structure is provided in the panel regions S10 and S11. In addition, the low-rigidity portion 94 is provided to further reduce the acoustic radiation from the panel regions S10 and S11.

  In the panel region S10 according to the present embodiment, one side of the high-rigidity portion 92 is No. 4 in contact with the cross member 29, in the panel region S11, the two sides of the high-rigidity portion 92 are No. 4 Since the four cross members 29 and the bent portion 54 are in contact with each other, the rigidity of the high-rigidity portion 92 can be greatly increased, and the rigidity difference from the low-rigidity portion 94 can be further increased. In this way, for example, even when the area of the panel area is relatively small and the rigidity of the panel area is originally relatively high, the rigidity difference from the low rigidity portion can be made large. It can be concentrated on the low rigidity part. Further, in the panel region S10, the vibration energy can be largely concentrated on the low-rigidity portion by the bracket 98 and the accessories 100 even by the weight difference.

Further, each of the high rigidity portions 92 is in contact with No. As described above, since the amount of vibration transmitted from the side sill 20 is small, the four cross member 29 can prevent the vibration transmitted to the panel regions S10 and S11 from increasing. As a result, no. The acoustic radiation due to vibration transmitted from the four cross members 29 to the panel regions S10 and S11 can be prevented from increasing, and the rigidity of the high-rigidity portion 92 is greatly increased so that the vibration reduction effect can be obtained more reliably. I can do it.
Therefore, even if there are restrictions on the vehicle body structure or processing such as the height, arrangement, and size as described above, the rigidity of the high rigidity portion is greatly increased by forming the high rigidity portion so as to contact the cross member. Thus, vibration energy in the panel region can be effectively reduced.

It is a perspective view which shows the underbody of the motor vehicle provided with the 1st thru | or 4th embodiment of this invention. FIG. 2 is an enlarged plan view (a) showing a panel region S1 according to the first embodiment of the present invention and a cross-sectional view (b) showing a cross-sectional structure in a vehicle front-rear direction viewed along the line II-II. It is sectional drawing (a) which shows the 1st modification of the cover member by 1st Embodiment of this invention, and the top view (b) which shows the 2nd modification of the cover member by 1st Embodiment. It is the expanded plan view (a) which shows panel area | region S2 by 2nd Embodiment of this invention, and sectional drawing (b) which shows the cross-sectional structure of the vehicle width direction seen along the IV-IV line. It is sectional drawing (b) which shows the cross-sectional structure of the vehicle width direction seen along the VV line and the enlarged plan view (a) which shows panel area | region S2 by the modification of 2nd Embodiment of this invention. It is sectional drawing (b) which shows the cross-sectional structure of the vehicle body front-back direction seen along the VI-VI line and the enlarged plan view (a) which shows panel area | region S13 by 3rd Embodiment of this invention. FIG. 8 is an enlarged plan view (a) showing a panel region S15 according to a third embodiment of the present invention and a cross-sectional view (b) showing a cross-sectional structure in a vehicle front-rear direction viewed along the line VII-VII. It is a diagram which shows the rigidity distribution (a) of the high-rigidity part and low-rigidity part of the floor panel by a comparative example, and the rigidity distribution (b) of the high-rigidity part and low-rigidity part by 3rd Embodiment of this invention. No. 4 according to the fourth embodiment of the present invention. FIG. 4 is a partially enlarged front view (a) seen from the front side of the vehicle body and a partially enlarged plan view (b) seen from the upper side of the vehicle body, showing the four cross members together with the side sill and pillar. No. 4 according to a modification of the fourth embodiment of the present invention. FIG. 4 is a partially enlarged front view (a) seen from the front side of the vehicle body and a partially enlarged plan view (b) seen from above the vehicle body, showing the four cross members together with the cross-sectional structure of the cross members and pillars. No. 4 according to the fourth embodiment of the present invention. FIG. 4 is an enlarged plan view (a) showing a 4-cross member and a panel region S10, and a cross-sectional view (b) showing a cross-sectional structure in the longitudinal direction of the vehicle body viewed along the line XI-XI. No. 4 according to the fourth embodiment of the present invention. FIG. 4 is an enlarged plan view (a) showing a 4-cross member and a panel region S11, and a cross-sectional view (b) showing a cross-sectional structure in the vehicle width direction viewed along the line XII-XII. It is the schematic (a) of the frame member for demonstrating the effect | action of 4th Embodiment of this invention, and the schematic (b) which shows the deformation | transformation state of the vehicle body structure containing an upper body.

Explanation of symbols

1 car underbody 2 first floor panel 4 second floor panel 6 third floor panel 18 front side frame 20 side sill 22 floor side frame 24 rear side frame 27 2 Cross member 28 3 cross member 29 4 cross member 29b connecting part 30 5 Cross member 35 Pillar 36 1 tunnel side member 37 No. 1 2 Tunnel side members 52, 54 Folded part (vibration regulating part)
56, 58 Bead part (vibration restricting part)
60 Opening 62 Stepped portion 64 Hole 66 Lid member 72, 82, 92 High rigidity portion, high weight portion 74, 84, 94 Low rigidity portion, low weight portion, peripheral portion 76, 86, 96 Asphalt vibration damping material 80, 116 Coating type damping material 98 Bracket 100 Auxiliary machinery 110 Rigidity reducing portion 112 Recesses S1 to S16 Panel region a Boundary portion between high rigidity portion and low rigidity portion

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 a vehicle longitudinal direction and a vehicle width direction,
The floor panel is formed with a panel region that is at least partially surrounded by the frame member,
The floor panel has an opening formed in a substantially central part of the panel region, and a peripheral part formed around the opening,
A lid member having increased rigidity and / or weight than the peripheral portion is fixed to the opening,
The lid member and the opening are configured as a high-rigidity part with increased rigidity and / or a high-weight part with increased weight than the peripheral part, and the peripheral part has a low-rigidity part and / or low-weight part. A vehicle body floor panel structure characterized by being constructed as follows.   The floor panel structure for a vehicle body according to claim 1, wherein a stepped portion projecting downward is formed in the opening, and the lid member is fixed to the stepped portion.   The vehicle body floor panel structure according to claim 1, wherein the lid member has a protruding portion integrally formed by protruding upward or downward along substantially the entire circumference of the peripheral portion thereof.   4. The vehicle body floor panel structure according to claim 1, wherein a thickness of the lid member is larger than a thickness of the peripheral portion.

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