JPS5968515A - Mount structure for exhaust muffler - Google Patents

Abstract

PURPOSE:To avoid a resonance of a muffler due to a vibrational input from an engine at idling by attaching a mass damper to the muffler and a mount rubber which intervenes between a mass damper bracket and a vehicle body. CONSTITUTION:A semicircular mass damper 16 that surrounds the underside circumferential coutour of a muffler 1 is fixed by welding with calking areas 1a, 1b at both ends of the muffler. The weight of the mass damper 16 is set to a desired value by selecting the thickness, and the bracket 17a is formed as a one piece with the mass damper 16 by bending. A mount rubber 18 intervenes between the bracket 17a and the vehicle body 11 and is connected by a bolt 19 on the bracket side and by a bolt 20 on the body side.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mounting structure for an exhaust system muffler for muffling the loud noise of engine exhaust from an automobile or the like.

As a conventional exhaust system muffler mounting structure, for example, the mounting structure shown in FIG. 1 is known. Fix the clamp 4 and bracket 5゜6, attach one end of the mount rubber 7.8 to the brackets 5 and 6, attach the other end of the mount rubber 7.8 to the bracket 9.10 on the vehicle body side, and then attach the placket. 9.10'f It was designed to be fixed to the vehicle body 11.

That is, as shown in FIG. 2, the muffler 1 is mounted on the vehicle body 11 by interposing the mount rubber 7.8 between the tubes 2.3 provided on both end surfaces of the muffler 1 and the vehicle body 11. It was of a structure that

In the conventional example shown in the figure, a lightweight heat shield plate 12 for preventing dead grass is fixed to the muffler 1 with pans 13, 13, and a diffuser 14 is attached to the tube 3.

However, in such a conventional exhaust system muffler mounting structure, the weight M of the exhaust system muffler including the heat shield plate 12,
The problem is that the vibration input of the engine in the idling rotation range causes a resonance phenomenon in the exhaust thread muffler, and the vibration input is transmitted to the vehicle body due to the resiliency constant of the entire mount rubber. was there.

As a solution to this problem, there is a method of simply increasing the weight of the heat shield plate 12, but in this case, there is a problem that the overlap must be increased considerably in order to prevent the resonance phenomenon from occurring.

The present invention has been made in view of the above-mentioned problems, and is a structure for an exhaust system muffler that increases the ratio of the amount of change in the natural frequency of the vibration system muffler to a constant weight increase (hereinafter referred to as the added weight efficiency ratio). The objective is to provide a mounting structure.

That is, in order to achieve this object, the present invention provides an exhaust system muffler mounting structure in which a muffler is mounted on a vehicle body via a mounting rubber, in which a mass damper is fixed to the i+7 muffler, and a bracket is attached to the mass damper. , and a mount rubber is interposed between the bracket and the vehicle body.

Therefore, in the exhaust system muffler mounting structure of the present invention, since the mass damper fixed to the muffler is provided with a bracket for mounting on the vehicle body, there is no need to provide a new bracket on the tube as in the conventional case. In order to obtain the same amount of change in the natural frequency of the vibrating string muffler, the added weight can be reduced compared to the conventional method, and the added weight efficiency ratio can be lowered to reduce the natural vibration of the exhaust system muffler. This has the effect of reducing the resonance of the exhaust thread muffler due to the vibration input, and the vibrations to the vehicle floor and steering wheel.

In addition, since the mount rubber is indirectly interposed in the muffler, the influence of heat on the mount rubber is reduced.
It also has the effect of improving durability.

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

In describing this embodiment, the mounting structure of an exhaust system muffler for an automobile will be taken as an example, and the same parts as in the conventional structure will be given the same reference numerals.

6, 4, and 5 show the exhaust system muffler of the first embodiment, and its configuration will be explained from FIG. gl
a,,lb are formed.

A tube 2 connects the engine to one end surface of the muffler 1, and a tail tube 3 is provided on the other end surface of the muffler 1. Reference numeral 16 denotes a mass damper, in which a semi-cylindrical mass damper 16 that follows the shape of the lower peripheral surface of the muffler 1 is fixed by welding to the caulked parts 1a and Ib.The weight of this mass damper 16 is equal to its thickness. A desired MW can be obtained by increasing or decreasing the MW. Reference numeral 17a denotes a bracket, which is integrally attached to the mass damper 16 by bending. Reference numeral 18 denotes a mount rubber, and by fixing the bracket 17a and the lower end of the mount rubber 18 with a mounting bolt 19, and fixing the vehicle body 11 and the upper end of the mount rubber 18 by adding another mounting bolt, There is a mount rubber 18' between the said placket,) 17a and the vehicle body 11? i: I am intervening.

The mounted state of the muffler 1 is such that the mass damper 16 fixed to the muffler 1 and the vehicle body 11 are mounted via mounting rubbers 18, as shown in FIG.

Therefore, in an automobile adopting the above-mentioned body structure, since the bracket (17a) for mounting on the vehicle body is provided on the mass damper 16, the added weight efficiency ratio can be increased and the natural frequency of the exhaust system muffler can be lowered. , resonance with the vibration input of the engine in the idling rotation range can be avoided, and vibrations in the vehicle floor and steering can be reduced.

This is clear from the steering vertical vibration graph based on experimental data shown in Figure 7. First, as shown by the solid line, if there is no mass damper in the exhaust system muffler,
The vibration acceleration amplitude level shows a high peak when the engine rotation speed is about 65 Orpm, and the resonance of the exhaust line muffler in the idling rotation range has a large effect on the vertical vibration of the steering wheel. On the other hand, when a mass damper with a 1 ky bracket 17aE is attached to the exhaust line muffler as shown by the dotted line, the peak of the vibration acceleration amplitude level is significantly lower than when there is no mass damper. It can be seen that the engine rotational speed at the time of . When a 2 ky mass damper is attached to the exhaust system muffler as shown by the dashed line,
If a 3 kP mass damper is attached to the exhaust system muffler as shown by the dotted chain line, the vertical vibration of the steering can be further reduced.

In this way, in the first embodiment, not only can the vehicle body float and steering vibration be efficiently reduced as described above, but also the mount rubber 18 is not directly mounted on the muffler 1, Since it is mounted on the vehicle body 11 via the mass damper 16, the influence of heat on the mount rubber 18 is reduced, and the durability of the mount rubber 18 can be improved.

Furthermore, since the mass damper 16 has a semi-cylindrical shape that follows the shape of the lower circumferential surface of the muffler 1, this mass damper 1
6 functions as a heat shield plate, and can prevent damage to the muffler 1 due to road surface interference.

Furthermore, the first practical example has a mass damper 16 and a bracket 17.
Since it is integrally formed with (A), the number of parts can be reduced compared to the case where (L) is attached as a separate part.

Next, a description will be given of the second embodiment shown in FIGS. 8 and 9. This second embodiment has the same structure as the first embodiment in that the bracket 17b is integrally formed with the mass damper 18 by embossing. They are different from each other.

Note that the operation and effect of the second embodiment are similar to those of the first embodiment.

Next, the sixth embodiment shown in FIGS. 10 and 11 will be explained. This third embodiment has a separate bracket) 17c
;The first and second points are fixed to the F mass damper 16.
This is different from the example.

Although one embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment. The shape of the bracket is not limited to the example, and the bracket may also be formed integrally with the mass damper, or a separately formed bracket may be fixed to the mass damper.

[Brief explanation of drawings]

Figure 1 is a side view showing the body structure of a conventional exhaust system muffler.
FIG. 2 is a schematic diagram showing the mounting structure of a conventional exhaust system muffler, FIG. 3 is a perspective view showing the mounting structure of the exhaust system muffler according to the first embodiment of the present invention, and FIG. 5 is a side view of the mounting structure, FIG. 6 is a schematic diagram of the mounting structure in the mounting state, and FIG. 7 is a graph showing vertical vibration of the steering with and without a mass damper. Figure 8 is the second
FIG. 9 is a sectional view of the mounting structure of the exhaust line muffler according to the embodiment, and FIG. 10 is a sectional view of the mounting structure of the exhaust line muffler of the third embodiment. Perspective view, 1st
FIG. 1 is a sectional view of the mounting structure in the mounted state. 1...Muffler, 16...Mass damper, 17a, 17
b. 17 c...Bracket, 18...Mount rubber,
11... Vehicle body. Patent applicant Nissan Motor Co., Ltd. Figure 1 Figure 2 Figure 8 Figure 1':j Figure 9 Figure 10 Figure 11

Claims (1)

[Claims] 1) In an exhaust system muffler mounting structure in which a muffler is mounted on the vehicle body via a mounting rubber, a mass damper is fixed to the muffler, a bracket is provided on the mass damper, and the bracket and the vehicle body are connected. A mounting structure for an exhaust system muffler, characterized in that the mount rubber is interposed therebetween.