JP2005207250A - Silencer using multiplex pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a silencer using a multiplex pipe capable of installing a resonance pipe by space-saving and varying a resonating frequency. <P>SOLUTION: The silencer is provided with an inner pipe 1 through which exhaust gas flows; an outer pipe 2 situated at the outside of the inner pipe; and a resonance pipe 3 forming a resonance chamber 3a between the outer pipe and the resonance pipe and situated at the outside of the outer pipe 2. Exhaust gas flow holes 1a and 2a are formed in the surfaces of the inner pipe 1 and the outer pipe 2, respectively, and formed such that the flow holes are radially relatively rotatable, and a part of exhaust gas in the inner pipe 1 is guided in the resonance chamber 3a through a space O where the exhaust gas flow holes 1a and 2a of the inner pipe 1 and the outer pipe 2 overlap each other. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a silencer for reducing exhaust noise of exhaust gas, and more particularly to a silencer using multiple tubes.

  Conventionally, a silencer of the form-hertz type or the like has been used as an exhaust gas silencer of an automobile, and these are provided with a resonance pipe having a resonance chamber separately from a main muffler and a sub muffler in the middle of an exhaust system. A technique for reducing exhaust noise by introducing a part of the gas into a resonance chamber and causing it to resonate is known (see Patent Documents 1 and 2).

In some cases, a resonance chamber is provided inside the main muffler or the sub muffler to achieve the same effect.
JP 2000-8830 A JP 2002-303117 A

  However, the invention described in Patent Document 1 has a problem that it is difficult to secure a mounting space because the resonance tube including the resonance chamber is formed so as to branch from the exhaust tube.

  In the inventions described in Patent Documents 1 and 2, since the frequency of resonance in the resonance chamber is constant, only exhaust noise having a specific frequency can be reduced.

  The present invention has been made paying attention to the above-mentioned problems, and an object of the present invention is to provide a silencer using a multiple tube in which a resonance chamber can be installed in a space-saving manner and the resonance frequency can be varied. is there.

  In order to solve the above-mentioned problem, in the invention according to claim 1, a resonance chamber is formed between the inner pipe through which the exhaust gas flows, the outer pipe arranged outside the inner pipe, and the outer pipe. A resonance tube disposed on the outside of the tube, and exhaust gas circulation holes are formed on the surfaces of the inner tube and the outer tube, respectively, and both are formed so as to be relatively rotatable in a radial direction by a driving means; A part of the exhaust gas in the inner pipe is guided to the resonance chamber through a space where the exhaust gas circulation holes in the outer pipe overlap.

  According to a second aspect of the present invention, in the silencer using the multiple pipe according to the first aspect, the driving means performs relative rotation in the radial direction of the inner pipe and the outer pipe by control with a stepping motor.

  In the first aspect of the present invention, a resonance chamber is formed between the inner tube through which the exhaust gas flows, the outer tube disposed outside the inner tube, and the outer tube, and the outside of the outer tube. The exhaust pipes are formed on the surfaces of the inner pipe and the outer pipe, respectively, and both are formed so as to be relatively rotatable in the radial direction by a driving means. The inner pipe and the outer pipe Because part of the exhaust gas in the inner pipe is led to the resonance chamber through the space where the exhaust gas circulation holes overlap, the drive means changes the opening cross-sectional area of the space where the exhaust pipe circulation holes overlap in the inner pipe and the outer pipe The resonance frequency can be varied.

  That is, the resonance frequency can be arbitrarily determined as compared with the conventional invention that can reduce the exhaust noise of a specific frequency, and the exhaust noise of the exhaust gas can be reduced in a wide range of frequencies.

  Further, the outer tube and the resonance tube can be arranged outside the inner tube, and can be mounted on a vehicle with a small space.

  In the invention according to claim 2, since the driving means performs the relative rotation in the radial direction of the inner tube and the outer tube by the control of the stepping motor, the relative rotation in the radial direction of the inner tube and the outer tube is slightly changed. In other words, the resonance frequency can be varied in minute units by adjusting the opening cross-sectional area of the space where the exhaust gas circulation holes overlap to a minute amount.

Examples of the present invention will be described below.
FIG. 1 is a plan view of a silencer using a multiple tube according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line S2-S2 of FIG. 1, and FIG. 3 is a cross-sectional view illustrating the inside of the inner tube and the outer tube. 4 is a cross-sectional view illustrating the inside of the resonance tube, and FIG. 5 is a cross-sectional view taken along line S5-S5 of FIG.
FIG. 6 is a view for explaining the operation and effect of the silencer using the multiple pipe of this embodiment, and FIG. 7 is a view showing the case where the opening cross-sectional area of the space where the exhaust gas circulation holes of the inner pipe and the outer pipe overlap is maximum. It is.

As shown in FIGS. 1 and 2, the silencer using the multiple tube of this embodiment has an inner tube 1, an outer tube 2, a resonance tube 3, and a driving means 4 as main components.
Both ends of the inner pipe 1 are interposed in the middle of an exhaust pipe (not shown), and exhaust gas flows from the left side to the right side in FIG.
In addition, as shown in FIG. 3, a total of 12 circular exhaust gas circulation holes 1a are formed on the surface of the inner tube 1, each having two circular exhaust gas circulation holes 1a (see FIG. 5).
Further, as shown in FIG. 4, the outer tube 2 is disposed outside the inner tube 1, and the surface thereof has two circular exhaust gas circulation holes 2a at a position rotated 90 degrees with the exhaust gas circulation hole 1a. A total of 12 points are formed each (see FIG. 5).
The inner tube 1 and the outer tube 2 are provided in close contact with each other. However, the inner tube 1 and the outer tube 2 are rotatable relative to each other in the radial direction while sliding relative to each other. Is regulated by convex portions 1b provided on the outer periphery of the inner tube 1 in the vicinity of both end portions of the outer tube 2.
In the present embodiment, as for the exhaust gas circulation holes 1a and 2a, the shape, the number of formation, and the formation position can be appropriately set as long as the space O described later can be formed.

The resonance tube 3 includes end plates 3b and 3b through which the outer tube 2 passes and a shell 3c fixed so as to wind around the outer periphery of the end plates 3b and 3b. It is provided so as to surround the outer tube 2 with the resonance chamber 3a formed therebetween.
The resonance tube 3 is fixed to the vehicle body side via a bracket (not shown), and the outer tube 2 is radially connected via the collars K and K provided between the shell 3c and the outer tube 2. It is fixed so that it can rotate.

The driving means 4 is mounted between a stepping motor 4a, a rotating roller 4b fixed to the rotating shaft of the stepping motor 4a, a rotating roller 4c fitted and fixed to the outer tube 2, and rotating rollers 4b and 4c. Drive belt 4d.
When the rotation shaft of the stepping motor 4a is driven in the direction of arrow X, the outer tube 2 rotates in the direction of arrow Y through the rotation roller 4b, the drive belt 4d, and the rotation roller 4c. The circulation hole 2a rotates relative to the exhaust circulation hole 2a of the inner pipe 1 in the radial direction.
Note that the stepping motor 4a of this embodiment is rotationally controlled in accordance with the engine speed of the automobile.

Hereinafter, the operation and effects of the present embodiment will be described.
In the muffler using the multi-tube constructed as described above, the stepping motor 4a is driven as shown in FIG. 6 when the engine speed is low, for example, 2000 rpm or less, where primary carous noise is likely to occur. Then, the outer tube 2 is rotated in the direction of the arrow by a predetermined angle α, and the exhaust gas in the inner tube 1 (the broken line in FIG. By leading a part of the gas to the resonance chamber 3a, a predetermined resonance frequency can be generated to reduce exhaust noise.
The predetermined angle α is adjusted and controlled by the stepping motor 4a in minute units corresponding to the engine speed.
Further, as shown in FIG. 7, when the outer tube 2 rotates 90 degrees, the opening cross-sectional area of the space O becomes the maximum.

  That is, the resonance frequency can be changed by changing the opening cross-sectional area of the space O where the exhaust gas circulation holes 1a, 2a of the inner pipe 1 and the outer pipe 2 overlap, and the resonance frequency can be changed continuously according to the engine speed. Exhaust noise can be reduced.

Accordingly, it is possible to continuously reduce the booming noise that is likely to occur from idling when the engine speed is extremely low to when the engine speed is relatively high, and it is possible to prevent the occurrence of booming noise in a wider range than the conventional invention.
Further, since the resonance tube 3 is arranged so as to surround the outer tube 2, the resonance tube 3 (resonance chamber 3a) can be formed in a smaller space than the conventional invention, and mounting on the vehicle is facilitated.

The embodiment of the present invention has been described above, but the specific configuration of the present invention is not limited to the present embodiment, and the present invention includes any design changes that do not depart from the gist of the invention. It is.
For example, in the present embodiment, the stepping motor 4a is driven based on the engine speed, but these may be driven based on the exhaust amount, the fuel injection amount, or the like.

In addition, it is naturally conceivable to provide the inner tube 1 and the outer tube 2 described in this embodiment in the resonance chamber in the sub muffler or the main muffler. At this time, the driving means may be provided either inside or outside the sub muffler or the main muffler.
Furthermore, in the present embodiment, the structure in which the outer tube 2 is rotated relative to the inner tube 1 in the radial direction has been described, but it is only necessary that both of them rotate relative to each other to form the space O. And may be relatively rotated in the radial direction.

It is a top view of the silencer using the multiple tube of the example of the present invention. It is sectional drawing in the S2-S2 line | wire of FIG. It is sectional drawing explaining the inside of an inner tube | pipe and an outer tube | pipe. It is sectional drawing explaining the inside of a resonance tube. It is sectional drawing in the S5-S5 line | wire of FIG. It is a figure explaining the effect | action and effect of the silencer using the multiple tube of a present Example. It is a figure which shows the case where the opening cross-sectional area of the space where the exhaust-gas circulation hole of an inner tube and an outer tube overlaps is the largest.

Explanation of symbols

O space 1 inner tube 1a, 2a exhaust gas flow hole 1b convex portion 2 outer tube 3 resonance tube 3a resonance chamber 3b end plate 3c shell 4 driving means 4a stepping motor 4b, 4c rotating roller 4d driving belt

Claims (2)

An inner pipe through which exhaust gas flows, an outer pipe arranged outside the inner pipe, and a resonance pipe arranged outside the outer pipe by forming a resonance chamber between the outer pipe,
Forming exhaust gas flow holes on the surfaces of the inner tube and the outer tube, respectively, and forming both of them to be relatively rotatable in the radial direction by a driving means;
A silencer using a multiple pipe, wherein a part of the exhaust gas in the inner pipe is guided to a resonance chamber through a space where the exhaust pipe circulation holes of the inner pipe and the outer pipe overlap.   2. A silencer using a multiple tube according to claim 1, wherein the driving means performs relative rotation in the radial direction of the inner tube and the outer tube by control of a stepping motor.

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