JPH0333895B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention provides a method for attaching the exhaust pipe of an automobile to
The present invention relates to a dynamic damper device for effectively suppressing resonance based on engine vibration.

(Prior Art) Since the exhaust pipe of an automobile is directly connected to the engine through the manifold, it receives engine vibration through the manifold, and since it is elongated, it is subject to vibrations. It is known that there are several resonance points. Since such resonance of the exhaust pipe due to engine vibration causes problems such as fatigue strength of pipe welds, it is desirable to suppress it as much as possible.

For this reason, conventionally, a dynamic damper device as a vibration absorber having a structure as shown in FIG. 6 is attached to a predetermined position of the exhaust pipe to suppress the resonance. That is, such a dynamic damper device consists of a mass 2 having an appropriate mass, a mounting side fitting 4, and a rubber body 6 that connects them, and is connected to an exhaust pipe 8 through an appropriate mounting member.
This allows the vibration amplitude of the exhaust pipe 8 to be kept small during resonance.

(Problem) However, such conventional dynamic damper devices do not have a fail-safe function.
Moreover, since preliminary compression cannot be applied to the rubber body 6, the bond between the rubber body 6 and the mass 2 or the mounting bracket 4 is likely to peel off, causing the mass 2 to fall off and be lost. There was a fear that it would happen.

In addition, in such a dynamic damper device, since the rubber body 6 connecting the masses 2 is block-shaped, the mass 2 required in the longitudinal direction of the exhaust pipe and in the direction perpendicular thereto is
Tuning the different resonant frequencies of
It was extremely difficult.

(Solution Means) Here, the present invention provides a dynamic damper device for an automobile exhaust pipe that can solve all of the above problems, and is characterized by a mass body that is located concentrically. A dynamic damper base is formed by connecting an outer cylindrical metal fitting as a mounting side metal fitting and an inner cylindrical metal fitting as a mounting side metal fitting with a predetermined viscoelastic body interposed between them. Both ends of the shaft member inserted through the inner cylindrical metal fitting are supported by predetermined mounting brackets, and the shaft member is attached to the exhaust pipe.

In addition, in the case of such a dynamic damper device, the viscoelastic body generally has a structure in which the outer cylindrical metal fitting and the inner cylindrical metal fitting are connected by a plurality of legs extending in the radial direction. This is desirable, and thereby the directionality of the spring in the viscoelastic body acting as a spring can be more effectively resolved and tuning can be facilitated.

Preferably, a predetermined heat shield plate is provided in the space between the outer cylindrical metal fitting of the dynamic damper base and the exhaust pipe portion facing the outer cylindrical metal fitting. By shielding the radiant heat, deterioration of the dynamic damper base, more specifically, deterioration of the viscoelastic body due to heat is prevented, and its durability is improved. In this case, the heat shield plate is preferably formed in a U-shape, and both ends of the U-shape are attached to both ends of the shaft member inserted through the inner cylinder fitting. Become.

Furthermore, in the present invention, a heat insulating washer is generally interposed at the attachment portion between the shaft member and the attachment bracket, thereby preventing heat transfer from the attachment bracket to the dynamic damper base side. be effectively suppressed.

(Example) Next, in order to clarify the present invention more specifically, examples of the present invention will be described in detail based on the drawings.

First, in FIGS. 1 and 2, 10 is a dynamic damper base body. As is clear from FIGS. 3 and 4, this dynamic damper base 10 consists of an outer cylindrical fitting 12 as a mass body having a predetermined mass, and an inner cylindrical fitting 12 as a mounting side fitting having a slightly longer length. The cylindrical fitting 14 is positioned concentrically with the rubber 16 as a viscoelastic body.
It is constructed by connecting the two. Further, as shown in the figure, the rubber 16 connecting the outer cylindrical metal fitting 12 and the inner cylindrical metal fitting 14 is constituted by four legs 18 arranged at predetermined intervals in the circumferential direction and extending in the radial direction. has been done. Note that such a dynamic damper base 10
is generally manufactured by vulcanization molding the rubber 16 in the presence of the outer cylindrical metal fitting 12 and the inner cylindrical metal fitting 14, and further by drawing the outer cylindrical metal fitting 12 after the vulcanization molding. , precompression is applied to the rubber 16.

Then, such a dynamic damper base 1
0, as shown in FIGS. 1 and 2, a bolt 20 as a shaft member is inserted into the inner cylindrical metal fitting 14, and both ends of the bolt 20 in the axial direction of the dynamic damper base 10 are connected to each other. At this position, it is supported by a substantially U-shaped mounting bracket 22 and attached to an exhaust pipe 24.
More specifically, with the dynamic damper base 10 positioned within the mounting bracket 22 fixed to the exhaust pipe 24, bolts are inserted into the mounting holes 26 at both ends of the mounting bracket 22 and into the inner cylinder fitting 14. 20 is inserted through and fixed with a nut 28.

Furthermore, when installing the dynamic damper base 10, a heat shield plate 30 having a substantially U-shape is provided.
is similarly inserted and attached to the bolt 20 so as to be located in the space between the outer cylinder metal fitting 12 and the exhaust pipe 24 portion facing it.
Furthermore, in order to prevent heat transfer from the mounting bracket 22, insulating washers 32 made of a heat insulating material such as asbestos are interposed on both sides of the mounting portion of the mounting bracket 22.

A dynamic damper device with such a structure is
A portion of the exhaust pipe 24 that is most effective in suppressing resonance,
For example, as shown in FIG. 5, it is installed at a position close to the catalytic converter 36 in the exhaust pipe 24 between the muffler 34 and the catalytic converter 36. When the exhaust pipe 24 resonates, the vibration is effectively damped by the action of the dynamic damper mechanism that includes the outer cylinder metal fitting 12 as a mass body and the rubber 16 as a spring. This allows the amplitude to be reduced.

In the dynamic damper device having such a structure, the bolt 20 is inserted through the dynamic damper base 10, and both ends of the bolt 20 are supported by the mounting brackets 22. Such a dynamic damper base 1
The outer cylindrical metal fitting 12 constituting the 0 does not fall off at all, and therefore, unlike conventional devices, an effective fail-safe function can be demonstrated.Moreover, the rubber 16, which functions as a spring,
From the place interposed between the outer cylindrical metal fitting 12 and the inner cylindrical metal fitting 14, a squeezing operation is applied to the outer cylindrical metal fitting 12, or the inner cylindrical metal fitting 14 is
Such rubber 1 can be easily pre-compressed by expanding the diameter of the side.
The problem of peeling of the adhesive surfaces between the outer cylindrical metal fitting 12 and the inner cylindrical metal fitting 14 and the outer cylindrical metal fitting 14 can also be effectively alleviated, thereby making it possible to significantly improve their durability.

Furthermore, the connection structure using the rubber 16 that connects the outer cylindrical metal fitting 12 and the inner cylindrical metal fitting 14 constituting the dynamic damper base 10 also has a relatively high degree of freedom and can be designed arbitrarily.
By changing the number and shape of , the resonance frequency of the outer cylinder fitting 12 as a mass body can be relatively freely controlled in the axial direction of the dynamic damper base 10 (longitudinal direction of the exhaust pipe 24) and in the direction perpendicular thereto. Since it can be designed, the spring of the dynamic damper base 10 has no directionality.
It also exhibits the feature of easy tuning operation.

Furthermore, in conventional dynamic damper devices for automobile exhaust pipes, there was a risk that the viscoelastic material such as rubber would receive radiant heat from the exhaust pipe 24 via the mounting metal fittings, causing deterioration. According to such a structure, the dynamic damper base 10 and the exhaust pipe 2
Since the heat shield plate 30 is provided so as to partition the space between the exhaust pipe 24 and
The radiant heat from the damper base 10 can be effectively shielded, and the deterioration of the rubber 16 constituting the dynamic damper base 10 can be effectively suppressed, and its durability can also be improved.

Furthermore, in the structure of the above example, a heat insulating washer 32 is interposed between the mounting bracket 22 and the bolt 20 to prevent heat transfer from the exhaust pipe 24 through the mounting bracket 22. Because of this, heat transfer to the dynamic damper base 10 side is also well suppressed. This effectively suppresses deterioration of the rubber 16 due to heat transfer.

In addition, in the structure of the above example, the mounting bracket 22 that supports the dynamic damper base 10 is
Although it is formed in a substantially U-shape and is configured to facilitate attachment to the exhaust pipe 24, it is by no means limited to such a shape; Any shape of mounting bracket may be used as long as it can support the shaft member 20 at both ends thereof, and the heat shield plate 30 may also be mounted using bolts 2 as in the above example.
Instead of changing the structure to one that can be inserted through the 0 and installed,
A structure in which it is supported by the mounting bracket 22 or the like can also be adopted as appropriate.

In addition, various changes, modifications, improvements, etc. may be made to the present invention without departing from the spirit of the present invention, although not illustrated in detail. It goes without saying that this also includes the following.

(Effects of the Invention) As is clear from the above explanation, the dynamic damper device according to the present invention can be attached to the exhaust pipe of an automobile to effectively suppress the resonance phenomenon, and is capable of effectively suppressing the resonance phenomenon of the exhaust pipe of an automobile. to the exhaust pipe,
A mass body attached via a viscoelastic material such as rubber is configured as a cylindrical outer metal fitting, and a shaft member is provided so as to pass through the outer cylinder metal fitting, and both ends of the shaft member are attached with mounting brackets. Since it has become possible to be supported,
Even if the outer cylinder fitting were to come off the viscoelastic body, it would never fall off and be lost.
This is where an effective fail-safe function can be demonstrated. In addition, even when connecting the outer cylinder fitting to the inner cylinder fitting using a viscoelastic body, since the degree of freedom of the connection is high, it is relatively unaffected by the directionality of the spring of the viscoelastic body. , it became possible to effectively perform the tuning operation of the resonant frequency.

[Brief explanation of drawings]

FIG. 1 is an explanatory longitudinal cross-sectional view showing an example of a dynamic damper device according to the present invention, and corresponds to the II cross-section in FIG. 2. FIG. 3 is a longitudinal sectional view of the dynamic damper base in the device illustrated in FIGS. 1 and 2, and corresponds to the − section in FIG.
The figure is an explanatory cross-sectional view of FIG. 3, FIG. 5 is an explanatory view showing an example of the mounting position of the dynamic damper device with respect to the exhaust pipe, and FIG. 6 is a cross-sectional view showing a conventional dynamic damper device. It is a diagram. 10: Dynamic damper base, 12: Outer cylinder metal fittings, 14: Inner cylinder metal fittings, 16: Rubber, 18: Legs,
20: Bolt, 22: Mounting bracket, 24: Exhaust pipe, 28: Nut, 30: Heat shield plate, 32: Heat insulating washer.

Claims (1)

[Claims] 1. An outer cylindrical metal fitting as a mass body and an inner cylindrical metal fitting as a mounting side metal fitting, which are positioned concentrically, are connected by a predetermined viscoelastic body interposed between them. The present invention is characterized in that a dynamic damper base is used, and the dynamic damper base is supported by predetermined mounting brackets at both ends of a shaft member inserted through the inner cylindrical metal fitting, and is attached to an exhaust pipe. Dynamic damper device for automobile exhaust pipes. 2. The dynamic damper device according to claim 1, wherein the viscoelastic body connects the outer cylindrical metal fitting and the inner cylindrical metal fitting through a plurality of radially extending legs. 3. In the space between the outer cylindrical metal fitting of the dynamic damper base and the exhaust pipe portion facing the outer cylindrical metal fitting,
3. The dynamic damper device according to claim 1, wherein a predetermined heat shield plate is provided to shield radiant heat from the exhaust pipe. 4. The dynamometer according to claim 3, wherein the heat shield plate has a substantially U-shape, and both ends of the U-shape are respectively attached to both ends of a shaft member inserted through the inner cylindrical metal fitting. Mitsuku damper device. 5. Claims 1 to 5, wherein a heat insulating washer is interposed at a mounting portion between the shaft member and the mounting bracket to suppress heat transfer from the mounting bracket to the dynamic damper base side. The dynamic damper device according to any one of Item 4.