JP4009980B2 - Bumper reinforcement mounting structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a bumper reinforcement mounting structure for supporting a bumper cover at a body end in a vehicle such as a passenger car.
[0002]
[Prior art]
Currently, a dynamic damper (D / D) is attached to the body to improve the low frequency phenomenon caused by the body. In other words, for low-frequency phenomena caused by body bending resonance, a very heavy D / D is added to either the front or back of the body so as to correspond to the size of the entire body structure.・ Measures were taken to reduce vibrations.
[0003]
[Problems to be solved by the invention]
However, measures to improve the low-frequency phenomenon using D / D require an additional weight of 1 kg at least on one side, and it is difficult to obtain an effect synchronized with left and right. Moreover, it is practically impossible to mount a device having the same feature on the left and right. On the other hand, in order to improve without using D / D, a significant improvement in the body structure is required. In this case, the body structure cannot be improved only for the purpose of countermeasures for the low frequency phenomenon without considering other factors such as safety.
[0004]
An object of the present invention is to provide a bumper reinforcement mounting structure that can easily and reliably take measures to improve a low-frequency phenomenon.
[0005]
[Means for Solving the Problems]
The present invention is a bumper reinforcement mounting structure for supporting a bumper cover at a body end, and includes an elastic body having a groove, a hole into which the elastic body is once set and inserted, and an engagement hole that engages with the groove. And the bumper reinforcement is engaged with the bumper arm on the body side through the elastic body. Supported.
[0006]
In the bumper reinforcement mounting structure of the present invention, the elastic body is a cushion rubber fixed to a bumper arm through a color spacer.
Furthermore, in the bumper reinforcement mounting structure of the present invention, the elastic body is fixed to the bumper arm by fastening means inserted through a color spacer.
[0007]
According to this invention, the bumper reinforcement is supported by the bumper arm on the body side via the elastic body, so that the bumper reinforcement as the structural component is converted into a functional component as D / D. Here, to explain with reference to the drawings, a typical generation and transmission path of a low-frequency phenomenon (22 to 23 Hz) is caused by engine vibration during idling as shown in FIG. Will occur.
[0008]
In this case, the body is bent twice. In the case of having a side member as shown in FIG. 2A, the side member vibrates in a two-node bending mode as indicated by a dotted line in FIG. Therefore, this is made to function as D / D using bumper reinforcement on the body rear part.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of a bumper reinforcement mounting structure according to the present invention will be described with reference to the drawings.
FIG. 3 shows the periphery of the body rear portion to which the present invention is applied. Left and right bumper arms 3 are attached to the body 1 via bolts 2. The bumper reinforcement 4 is attached to the rear part (A part) of each bumper arm 3 by the attachment structure of the present invention. The bumper cover 5 is supported by the bumper reinforcement 4.
[0010]
4 and 5 show the mounting portion of the bumper reinforcement 4. The bumper reinforcement 4 is supported by the bumper arm 3 on the body 1 side via an elastic body. As shown in FIG. 6, this elastic body is a cushion rubber 7 that is fixed to the bumper arm 3 via a collar spacer 6. Bolts 8 are inserted into the collar spacer 6, and the bolts 8 are screwed into nuts 9 on the bumper arm 3 side.
[0011]
As shown in FIG. 7, the cushion rubber 7 has a groove 7 a for engaging with the bumper reinforcement 4. In order to attach the bumper reinforcement 4, the bumper reinforcement 4 is formed with a hole 4 a into which the cushion rubber 7 is temporarily inserted when engaged with the cushion rubber 7. The cushion rubber 7 is set in the hole 4a as indicated by an arrow C, and the cushion rubber 7 is further displaced as indicated by an arrow D, whereby the groove 7a of the cushion rubber 7 can be engaged with the engagement hole 4b.
[0012]
In the above configuration, the bumper arm 3 is rigidly attached to the skeleton of the body, and thus can be regarded as a part of the body. Accordingly, the bumper reinforcement 4 and the body are coupled via the cushion rubber 7 which is an elastic body, so that the bumper reinforcement 4 itself plays a role of mass in D / D. As a result, it is possible to effectively take measures to improve the low frequency phenomenon without adding a heavy D / D.
[0013]
In this case, since the bumper reinforcement 4 is mounted by the same mounting structure on the left and right sides of the body, the left and right synchronization can be performed easily and appropriately. Moreover, since the bumper reinforcement 4, particularly the mounting portion (A portion) is surrounded by the bumper cover 5 in terms of durability, it is possible to completely prevent parts from falling. Therefore, it is not necessary to add a special means for preventing parts from falling.
[0014]
Here, the operation of the bumper reinforcement mounting structure according to the present invention was specifically verified. In this experiment, the vibration level and the like at that time were measured by exciting the rear end of the left side member in the vertical direction.
[0015]
FIG. 8 shows a change in excitation point inertance (which means an excitation point response and represents a vibration level at a point where a signal is input) with respect to a frequency. This example is aimed at obtaining an effect at 22.5 Hz, and is selected as a comparative example that is not D / D, that is, a bumper reinforcement firmly attached to the bumper arm.
[0016]
As can be seen from FIG. 8, according to the mounting structure of the present invention, an improvement of 6 to 7 dB relative to the comparative example at around 22.5 Hz aimed at improving the low frequency phenomenon by the D / D conversion of the bumper reinforcement 4. Is possible.
[0017]
Next, FIG. 9 shows a change in sound pressure sensitivity with respect to frequency. Here, the sound pressure sensitivity is expressed in decibels, and the reference sound pressure is 2 × 10 ⁻⁵ Pa. In this case, the numerical value of the sound pressure level matches the numerical value of the sound intensity level.
[0018]
As can be seen from FIG. 9, according to the mounting structure of the present invention, the “mountain” in the graph is compared with the comparative example at around 22.5 Hz aimed at improving the low frequency phenomenon by the D / D conversion of bumper reinforcement 4 ”Appears to lack half of the peak (higher frequency side of the peak; part E). In addition, in this case, the sound pressure level itself also decreases.
[0019]
As is clear from this verification result, in the bumper reinforcement mounting structure of the present invention, the bumper reinforcement 4 as a structural component can function as a D / D, thereby greatly reducing and improving vibration and sound pressure characteristics. it can.
[0020]
Note that the present invention can be effectively applied in the same manner as described above when modal analysis is performed on the vehicle body to which the present invention is applied, and as a result, even-node bending resonance contributes to the low-frequency phenomenon. Moreover, although the example of the bumper reinforcement of the body rear part has been described, it can also be applied to the bumper reinforcement of the front part, and the same effect as the above embodiment can be obtained.
[0021]
【The invention's effect】
As described above, according to the present invention, in the bumper reinforcement mounting structure for supporting the bumper cover at the end portion of the body, the bumper reinforcement itself is effectively used and converted into D / D, thereby making a special It is possible to realize a low frequency phenomenon improvement measure without adding a damper device or the like. As a result, cost and weight can be significantly reduced. In addition, in this case, there is an advantage that the left and right synchronization of the body can be easily and accurately performed.
[Brief description of the drawings]
FIG. 1 is a block diagram for explaining typical generation of a low-frequency phenomenon, a transmission path, and the like according to the present invention.
FIG. 2 is a diagram illustrating an example of a two-node bending resonance mode according to the present invention.
FIG. 3 is an exploded perspective view showing the periphery of a body rear portion in the embodiment of the present invention.
4 is an enlarged perspective view of a part A in FIG. 3;
5 is a cross-sectional view taken along line BB in FIG.
FIG. 6 is a cross-sectional view of a main part of a mounting portion of a bumper reinforcement according to the present invention.
FIG. 7 is an exploded view of a main part of a mounting portion of a bumper reinforcement according to the present invention.
FIG. 8 is a diagram showing the relationship between frequency and excitation point inertance in the present invention.
FIG. 9 is a diagram showing the relationship between frequency and sound pressure sensitivity in the present invention.
[Explanation of symbols]
1 Body 2 Bolt 3 Bumper Arm 4 Bumper Info 5 Bumper Cover 6 Color Spacer 7 Cushion Rubber 8 Bolt 9 Nut

Claims (3)

A bumper reinforcement mounting structure for supporting the bumper cover at the end of the body,
An elastic body having a groove,
A bumper reinforcement having a hole into which the elastic body is once set and inserted and an engagement hole to be engaged with the groove,
The groove is engaged with the engagement hole by temporarily setting the elastic body in the hole, and the bumper reinforcement is supported by the bumper arm on the body side via the elastic body. , Bumper reinforcement mounting structure. 2. The bumper reinforcement mounting structure according to claim 1, wherein the elastic body is a cushion rubber fixed to the bumper arm via a color spacer. 3. The bumper reinforcement mounting structure according to claim 2, wherein the elastic body is fixed to the bumper arm by fastening means inserted through a collar spacer.

Images