JP2007022249A - Lower vehicle body structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain lower vehicle body structure capable of suppressing vibration input to the vehicle body. <P>SOLUTION: A muffler 3 and a spare tire 4 are supported by a bracket 2 disposed on a floor panel 1a through a buffer member 8. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vehicle body lower structure.

  Conventionally, vibrations input to the vehicle body from the muffler (silencer) provided under the floor at the rear of the vehicle are likely to be a problem. To cope with this, dynamic dampers have been added or vehicle body rigidity has been improved. It was broken.

On the other hand, in a vehicle in which a spare tire is mounted under the vehicle body floor, a vehicle using the spare tire as a dynamic damper against vehicle body vibration is known (for example, Patent Document 1).
Japanese Patent Laid-Open No. 11-94018

  However, the dynamic damper disclosed in Patent Document 1 can only obtain an effect corresponding to the mass of the spare tire, and may not have a sufficient vibration suppressing effect. It was difficult to obtain a sufficient vibration suppression effect even with respect to vibration input from the muffler.

  Accordingly, an object of the present invention is to obtain a vehicle body lower structure capable of suppressing vibration input to the vehicle body in which a muffler and a spare tire are attached below the rear floor.

  The most important feature of the present invention is that the muffler and the spare tire are supported by a bracket that is disposed under the floor of the vehicle body via a buffer member.

  According to the present invention, since the masses of both the muffler and the spare tire can be used for the dynamic damper, the vibration input suppression effect can be further enhanced, and in particular, the vibration input at a lower frequency can be effectively suppressed. can do.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  (First Embodiment) FIG. 1 is a diagram showing a schematic configuration of a vehicle body lower structure according to this embodiment, in which (a) is a sectional view as seen from the rear side of the vehicle (A-A sectional view of (b). ), (B) are plan views viewed from the bottom of the vehicle body floor.

  In the present embodiment, a bracket 2 for attaching the muffler 3 and the spare tire 4 to the vehicle body 1 is disposed below the floor panel 1a at the rear portion of the vehicle body 1.

  The bracket 2 includes a plate-shaped spare tire mounting portion 5 that is substantially triangular in plan view, an arm portion 6 that is fixed to the rear end edge of the spare tire mounting portion 5 and extends toward the muffler 3 in the vehicle width direction, and an arm portion. 6 and a hook portion 7 made of a buffer member fixed to the end portion on the muffler 3 side, and a buffer member 8 made of an elastic body (for example, rubber) or the like interposed between the hook panel 7 and the floor panel 1a. In the state, it is attached to the floor panel 1a.

  In the present embodiment, the spare tire 4 is pressed against the bracket 2 so that the spare tire 4 and the bracket 2 are substantially integrated. Specifically, a shock absorber made of an elastic body (for example, rubber) is provided at the tip of the rod-like stay 10 extending downward from the floor panel 1a and passing through the spare tire mounting portion 5 and the through holes 5a, 4a of the spare tire 4. The annular pressing member 11 provided with the member 13 is packaged, and the nut 12 is tightened from the lower surface side of the pressing member 11. Then, at the three positions near the vertices of the triangle of the spare tire mounting portion 5 on the lower surface side of the bracket 2, the frustoconical projections 9 made of, for example, synthetic resin are disposed, and these projections 9 are used as spare tires. 4 is in contact with the upper surface of the rim 4b. Therefore, by tightening the nut 12, the spare tire 4 can be pressed against the protrusion 9 of the bracket 2 (spare tire mounting portion 5). The buffer member 13 suppresses the vibration of the spare tire 4 from being input to the vehicle body 1 via the stay 10.

  On the other hand, on the side wall of the muffler 3 on the spare tire 4 side, a bracket 14 is projected inward in the vehicle width direction, and an arm portion 14 a of the bracket 14 is fixed to the hook portion 7.

  Thus, in the present embodiment, the muffler 3 and the spare tire 4 are supported by the bracket 2 that is disposed under the vehicle body floor via the buffer member 8. Such a configuration can be regarded as a so-called dynamic damper in which an elastic shock-absorbing member 8 is interposed between the vehicle body 1 and a mass composed of the muffler 3, the spare tire 4, and the bracket 2.

  Therefore, in this embodiment, the total mass of the muffler 3, the spare tire 4, and the bracket 2 can be used as the effective mass of the dynamic damper, so that vibration input to the vehicle body 1 (particularly vibration input from the muffler 3) is increased. The suppression effect can be further increased, and in particular, vibration input at a lower frequency can be effectively suppressed.

  Furthermore, the elastic coefficient is appropriately set by adjusting specifications such as the material and shape of the buffer member 8, and the resonance frequency of the dynamic damper is set to a frequency with low sensitivity on the vehicle body 1 side or vibration from the muffler 3 or the like. It is preferable to set the frequency to a low input level.

  Further, according to the present embodiment, the projections 9 are provided at the three locations on the bracket 2, and these projections 9 are brought into contact with the rim portion 4 b of the spare tire 4. Spare tire 4 can be arranged more stably.

  (Second Embodiment) FIG. 2 is a diagram showing a schematic configuration of a lower body structure according to the present embodiment, in which (a) is a cross-sectional view as viewed from the rear side of the vehicle (a cross-sectional view along BB in (b)). ), (B) are plan views viewed from the underside of the vehicle body floor, and FIG. 3 is a side view of a spare tire mount used in the vehicle body lower structure. Note that the vehicle body lower part structure according to the present embodiment includes the same components as those in the first embodiment. Therefore, these constituent elements are denoted by common reference numerals and redundant description is omitted.

  In this embodiment, instead of the spare tire mounting portion 5 of the first embodiment, there is provided a spare tire mounting portion 5A formed by connecting rod-like members arranged radially at 120 ° (deg) in plan view. Yes.

  Further, in the first embodiment, the stay 10 is fixed to the floor panel 1a. In the present embodiment, however, a stay 10A that hangs down from the central portion 5b of the spare tire mounting portion 5A is provided, and the tip of the stay 10A is provided. By tightening the nut 12, the spare tire 4 is pressed against the spare tire mounting portion 5 </ b> A.

  Furthermore, in this embodiment, the front-end | tip part of each rod-shaped member which comprises 5 A of spare tire attachment parts is attached to the spare tire mount 15 fixed to the lower surface of the floor panel 1a. Specifically, the spare tire mount 15 is fixed to a case 15a in which a belt-like plate material is bent into a substantially U shape and an open end of the U shape is fixed to the lower surface of the floor panel 1a, and an inner surface of the case 15a. The buffer member 16 is provided, and the tip of each rod-shaped member of the spare tire mounting portion 5A is inserted and fixed to the buffer member 16.

  According to the above-described embodiment, the spare tire mount 15 as the mounting device to which the buffer member 16 is fixed is fixed to the lower surface of the floor panel 1a, and the bracket 2A is fixed to the buffer member 16; A configuration in which the bracket 2A is disposed via the buffer member 16 can be obtained as a relatively simple configuration.

  Also in this embodiment, since the total mass of the muffler 3, the spare tire 4, and the bracket 2A can be used as the effective mass of the dynamic damper, the effect of suppressing the vibration input to the vehicle body 1 is further enhanced compared to the conventional case. In particular, lower frequency vibration input can be effectively suppressed.

  (Third Embodiment) FIG. 4 is a view showing a schematic configuration of a vehicle body lower structure according to this embodiment, in which (a) is a cross-sectional view as seen from the vehicle rear side (C-C cross-sectional view of (b)). ), (B) are plan views viewed from the bottom of the vehicle body floor. Note that the vehicle body lower part structure according to the present embodiment includes the same components as those in the first embodiment. Therefore, these constituent elements are denoted by common reference numerals and redundant description is omitted.

  In the second embodiment, the spare tire 4 is pressed against the spare tire mounting portion 5A by the stay 10A fixed to the spare tire mounting portion 5A, whereas in the present embodiment, the stay 17 fixed to the floor panel 1a. Thus, the rubber portion 4c of the spare tire 4 is supported from below and pressed against the spare tire mounting portion 5B (bracket 2B).

  Specifically, for example, the stay 17 is formed by bending the pipe into a substantially U shape in a plan view or a substantially U shape in a side view, and the floor panel 1a is formed at a total of three or more locations around the spare tire 4. The spare tire 4 is suspended below the floor panel 1a by setting a section in contact with only the rubber portion 4c on the lower side of the spare tire 4 so as to bridge between the fixed portions. In this way, by bringing the stay 17 into contact with only the rubber portion 4 c of the spare tire 4, it is possible to suppress the vibration of the spare tire 4 from being input to the vehicle body 1 via the stay 17.

  Also according to the present embodiment described above, the spare tire 4 can be substantially integrated with the spare tire mounting portion 5 with a relatively simple configuration, and the same effect as in the above embodiment can be obtained. Moreover, according to this embodiment, there exists an advantage that the removal | desorption of the spare tire 4 can be performed more easily.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments, and various modifications can be made.

  For example, the structure of the bracket, its support structure, the method of fixing the muffler and spare tire to the bracket, etc. are not limited to those disclosed in the above embodiment, and can be variously modified.

  Further, as shown in FIG. 5, if projections 9A are formed with irregularities such as a step 9a and used as a guide (positioning mechanism) for guiding to a predetermined mounting position when the spare tire 4 is mounted, the mounting and dismounting is possible. There is an advantage that it can be performed more easily, individual differences in the mounting position are suppressed, and desired characteristics can be easily obtained. In the example of FIG. 5, the rim portion 4b of the spare tire 4 is brought into contact with the step 9a.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows schematic structure of the vehicle body lower part structure concerning 1st Embodiment of this invention, Comprising: (a) is sectional drawing (AA sectional drawing of (b)) seen from the vehicle rear part side, (b) is The top view seen from the vehicle body floor lower side. It is a figure which shows schematic structure of the vehicle body lower structure concerning 2nd Embodiment of this invention, Comprising: (a) is sectional drawing seen from the vehicle rear side (BB sectional drawing of (b)), (b) is The top view seen from the vehicle body floor lower side. The side view of the spare tire mount used by the vehicle body lower part structure concerning 2nd Embodiment of this invention. It is a figure which shows schematic structure of the vehicle body lower part structure concerning 3rd Embodiment of this invention, Comprising: (a) is sectional drawing (CC sectional drawing of (b)) seen from the vehicle rear part side, (b) is The top view seen from the vehicle body floor lower side. The side view which shows an example of the protrusion used with the vehicle body lower part structure concerning embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Car body 2,2A, 2B Bracket 3 Muffler 4 Spare tire 4b Rim part 4c Rubber part 8,16 Buffer member 9,9A Protrusion 9a Step part (unevenness)
17 Stay

Claims (5)

  A vehicle body lower structure characterized in that a muffler and a spare tire are supported by a bracket disposed under a vehicle body floor via a buffer member.   The vehicle body lower part structure according to claim 1, wherein a mounting device to which the buffer member is fixed is fixed below the floor of the vehicle body, and the bracket is fixed to the buffer member.   The vehicle body lower part structure according to claim 1 or 2, wherein a rubber portion of the spare tire is supported from below by a stay attached to the vehicle body.   The vehicle body lower part structure according to any one of claims 1 to 3, wherein three protrusions are provided on the bracket, and the protrusions are brought into contact with a rim portion of a spare tire. The vehicle body lower structure according to claim 4, wherein the protrusion is formed with unevenness for guiding the spare tire to a predetermined mounting position.

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