JP2006151104A - Vibration damping structure for vehicle body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration damping structure for a vehicle body, capable of obtaining high vibration damping effect without increasing weight. <P>SOLUTION: An engine room and a vehicular interior are divided by a dash panel 3. On a vertical wall 13 of the dash panel 3, a curving portion 23 made from undulations 25 of periodic waves is formed in a vehicle body width direction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vehicle body damping structure, and more particularly, to a vehicle body damping structure in which a damping effect is uniform in each part of a vehicle body panel.

  In general, body panels such as dash panels and floor panels receive vibrations caused by engine and drive system components and road surface irregularities while the vehicle is running. There is a risk of sound waves. In order to prevent this, conventionally, for example, a so-called square bead having a trapezoidal cross section is formed on the dash panel, and a vibration damping material is applied to the surface side of the square bead to reduce the vibration of the vehicle body. (For example, refer to Patent Document 1).

In addition to this vibration damping material, a technique for forming a dash panel using a sandwich steel plate and a technique for additionally installing a reinforcement panel at a predetermined portion of the dash panel are employed.
Japanese Patent Application Laid-Open No. 11-334653

  However, the conventional example has a problem that the weight increases because square beads are formed on the dash panel and the damping material is applied.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a vehicle body damping structure capable of obtaining a high damping effect without increasing the weight.

  In order to achieve the above object, the present invention defines an engine room and a vehicle interior by a dash panel, and a curved portion that repeats wavy undulations periodically in the vehicle longitudinal direction on the surface of the dash panel. It is characterized by integrally molding.

  According to the present invention, the curved portion that periodically repeats the wavy undulations is provided on the dash panel. Therefore, the surface rigidity can be improved without increasing the weight of the dash panel. Therefore, vibration and noise generated in the engine room can be efficiently suppressed so as not to enter the vehicle compartment.

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

  FIG. 1 is a perspective view showing a vehicle body front portion according to the present embodiment.

  A pair of left and right body side panels 1 are disposed on the side of the vehicle body, and front end portions of the body side panels 1 are bridged by a dash panel 3 extending in the vehicle width direction. The dash panel 3 is disposed so as to define a front engine room and a rear vehicle compartment. An air box 5 extends along the vehicle width direction above the dash panel 3, and the lower end of the front window 7 is supported on the upper end portion of the air box 5. And the member member 9 is arrange | positioned along the vehicle width direction in the center part of the height direction of the dash panel 3. As shown in FIG. The front end of the floor panel 11 is joined to the lower end of the dash panel 3, and the floor panel 11 extends from the lower part of the dash panel 3 toward the rear of the vehicle.

  2 is a perspective view showing a curved portion of the dash panel of FIG. 1, and FIG. 3 is a cross-sectional view taken along line AA of FIG.

  As shown in FIG. 2, the vertical wall 13 of the dash panel 3 has a harness through-hole 15 to the cockpit module that opens to the passenger seat side, and the longitudinal direction extends obliquely at the center in the vehicle width direction. A hole is formed. The long hole is a first valve hole 17 of the HVAC (air conditioning module), and a second valve hole 19 of the HVAC (air conditioning module) formed in a substantially rectangular shape in a front view is formed on the right side thereof. Is formed. A right circular master cylinder through hole 20 is formed on the rightmost side.

  As shown in FIG. 3, a curved portion 23 is formed in the dash panel 3 from the harness through hole 15 to an end portion 19 a of the peripheral portion of the second valve hole 19. That is, the total length W of the curved portion 23 is a length from the end edge of the harness through hole 15 to the end portion 19 a of the peripheral portion of the second valve hole 19 along the vehicle width direction. The curved portion 23 is formed in a shape in which a periodic wavy undulation 25 is repeated in the vehicle front-rear direction, and the undulation 25 is formed in a substantially sinusoidal cross section.

  That is, as shown in FIG. 3 which is an AA cross-sectional view of FIG. 2, the curved portion 23 includes a top portion 27 that is convex on the vehicle front side and a trough portion 29 that is convex on the vehicle rear side. And an inclined portion 31 that continuously connects the top portion 27 and the valley portion 29. A curve connecting these top 27, trough 29, and inclined part 31 is formed in a substantially sine wave cross section.

  A flat portion 33 extending along the vehicle width direction is formed on the upper and lower portions of the curved portion 23, and extends from the curved portion 23 along the vertical direction and is continuously connected to the flat portion 33. Yes. For example, when the undulation 25 closest to the harness through-hole 15 is viewed along the vertical direction, it gradually leads to an inclined surface 35 that extends obliquely rearward and upward from the lower flat portion 33, and the inclined surface 35 At the apex, it leads to the relief 25. On the other hand, as it goes downward from the upper plane portion 33, it is connected to an inclined surface 35 that gradually extends rearward and downward, and is formed so as to be connected to the undulation 25 at the apex of the inclined surface 35.

  Further, as shown in FIG. 3, the cross section of the undulation 25 is formed by a plurality of regularly repeating sine waves, and the top 27 of the sine wave at a predetermined position and the top 27 of the sine wave adjacent to this sine wave are: They are arranged apart from each other by λ along the vehicle width direction. Further, the distance between the top portion 27 and the trough portion 29 of the sine wave is arranged by an amplitude T along the vehicle front-rear direction.

  FIG. 4 is a graph showing the value of the damping effect with respect to the wavelength ratio according to the present embodiment.

  The horizontal axis represents the wavelength ratio that is one wavelength of the undulations 25 with respect to the entire length of the curved portion 23. That is, this wavelength ratio indicates (one wavelength of undulation 25: λ) / (full length of curved portion 23: W). The vertical axis indicates the degree of the vibration suppression effect, and indicates that the vibration suppression effect is higher toward the top of the graph.

  As shown in this graph, it can be seen that the vibration damping effect is high until the wavelength ratio is in the vicinity of 0.2 to 0.5, and when the wavelength ratio exceeds 0.5, the vibration damping effect is rapidly reduced.

  FIG. 5 is an enlarged graph of a part of FIG.

  When the wavelength ratio is in the range of 0.2 to 0.55, the damping effect of a predetermined value shown by a thin solid line in FIG. 5 can be satisfied, and at a wavelength ratio of 0.3 to 0.45, it is even higher. A vibration control effect can be obtained.

  According to the embodiment of the present invention, the following effects are obtained.

  As shown in FIG. 2, since the upper and lower vertical walls 13 of the bending portion 23 are formed with the flat portion 33 connected to the bending portion 23, the upper and lower portions of the bending portion 23 are reliably supported by the flat portion 33. Therefore, the surface rigidity is surely improved. That is, when the dash panel 3 is simply folded in a wave shape and there is no flat portion 33 at the upper and lower portions, the surface rigidity of the dash panel 3 is reduced, so that the vibration damping effect is reduced and the engine room is reduced. This makes it easier for the sound inside to enter the vehicle compartment.

  However, in the present embodiment, since the flat portion 33 is formed above and below the curved portion 23, the surface rigidity of the dash panel 3 is greatly improved by the combination of the curved portion 23 and the flat portion 33.

  Since the undulation 25 extends in the vehicle width direction and is formed in a sine wave shape having a cross section that repeats the undulation in the vehicle front-rear direction, there is no variation in the vibration suppression effect due to each part of the curved portion 23, and a uniform vibration suppression effect Can be obtained.

  Since the wavelength ratio which is the value of one wavelength of the undulation 25 having a sinusoidal cross section with respect to the entire length of the curved portion 23 in the vehicle width direction is 0.2 to 0.55, as shown in FIG. Obtainable. As described above, this wavelength ratio is a value obtained by dividing one wavelength λ of the undulation 25 having a sinusoidal cross section by the total length W of the curved portion 23 in the vehicle width direction.

  When the wavelength ratio is 0.3 to 0.45, a higher vibration damping effect can be obtained.

It is a perspective view which shows the vehicle body front part by this embodiment. It is a perspective view which shows the curved part of the dash panel of FIG. It is an expanded sectional view by the AA line of FIG. It is a graph which shows the value of one period of undulation with respect to the full length of the curved part by this embodiment. It is the graph which expanded a part of FIG.

Explanation of symbols

3 ... Dash panel 13 ... Vertical wall 23 ... Curved portion 25 ... Undulating 33 ... Plane portion

Claims (4)

  A vibration damping structure for a vehicle body, characterized in that a curved portion made of periodic wavy undulations is provided on a vertical wall of a dash panel that defines an engine room and a vehicle interior.   2. The vehicle body damping structure according to claim 1, wherein the undulation is formed in a cross-sectional sine wave shape that extends along the vehicle width direction and repeats the undulation in the vehicle longitudinal direction.   The vibration damping structure for a vehicle body according to claim 2, wherein a planar portion connected to the curved portion is formed on the upper and lower vertical walls of the curved portion.   The vibration damping structure for a vehicle body according to claim 3, wherein a value of one wavelength of the undulation with respect to the entire length of the curved portion in the vehicle width direction is 0.2 to 0.55.

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