JP2007127075A - Resonator structure for muffler - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve installation efficiency without restriction in a plate press-in direction to an exhaust pipe and reduce manufacturing cost. <P>SOLUTION: A resonance hole 8 communicating with an inside of an exhaust pipe 6 is formed on a notch 6c side end part of a recessed part 6b by recessing the recessed part 6b of a predetermined length along a longitudinal direction of an exhaust pipe 6 with the notch 6c put on a side wall of the exhaust pipe 6 in a circumference direction made as one end. A resonance pipe 10 is constructed together with a blocked plate body 9 blocked under a condition the same is stored in an outer circular arc of the exhaust pipe with an opening part of the recessed part 6b left outside at an end part side opposite to the resonance hole 8. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a resonator structure for a muffler.

  As a conventional muffler resonator structure of this type, for example, as shown in the cross-sectional view of FIG. 4, outer plates 102 and 103 are attached to both front and rear ends of a laterally cylindrical outer shell 101 to close the openings at both ends. The silencer chamber is formed by the above, and further, by dividing the silencer chamber in the front-rear direction by the inner plate 104, the resonance chamber 105 constituting the resonator and the sound absorbing chamber 106 constituting the sound absorbing silencer are partitioned and formed, An exhaust pipe 107 is provided in a state of passing through both the outer plates 102 and 103 and the inner plate 104, and one end portion of a resonance pipe 109 is formed in a resonance hole 108 formed in the exhaust pipe 107 passing through the resonance chamber 105. Are coupled and fixed so that the resonance tube 109 protrudes into the resonance chamber 105 to thereby form a Helmholtz-type resonator. There is obtained by constituting the over data (e.g., see Patent Document 1.) ... Conventional Example 1.

Further, as shown in FIG. 5 (plan view), FIG. 6 (side view), and FIG. 7 (cross-sectional view taken along the line CC in FIG. 6), the resonance hole 108 provided in the exhaust pipe 107 and the resonance hole 108. A cover 111 that has a gap and covers the outside and is formed in the shape of a bowl having a substantially semicircular cross section along the exhaust pipe 107 to form the resonance path 110 is attached and fixed, and the end of the cover 111 on the resonance hole 108 side is fixed. It is known that a resonance tube 109 communicating with the resonance chamber 105 is formed between the outer surface of the exhaust pipe 107 and the inner surface of the cover 111 by forming the closed state (see, for example, Patent Document 2). ..) Conventional example 2.
JP 2002-303117 A JP 2004-169622 A

  However, in the conventional muffler resonator structure, the resonance pipe 109 is constituted by a separate pipe member or cover 111, and the resonance pipe 109 is formed in the resonance chamber 108 from the resonance hole 108 formed in the exhaust pipe 107. Since the structure is mounted and fixed in a state of protruding toward the inside 105, there are the following problems.

  That is, in the muffler assembling process, the plates 102, 103, 104 are press-fitted to a predetermined position while the exhaust pipe 107 is passed through the press-fitting holes formed in the outer plates 102, 103 and the inner plate 104. However, as in the conventional example, if the resonance pipe 109 is projected in the middle of the exhaust pipe 107, the press-fitting directions of the plates 102, 103, and 104 are restricted, respectively. There is a problem that assembly workability is poor.

The resonance frequency f at which the Helmholtz type resonator resonates is generally represented by the following Helmholtz equation.
f = C × 2π × √S / L × V
C is the speed of sound, S is the cross-sectional area of the resonance tube 109, L is the length of the resonance tube 109, and V is the volume of the resonance chamber 105.

  That is, for example, in order to effectively reduce the primary booming noise when the rotational speed of the internal combustion engine is low at 2000 rpm or less, the volume V of the resonance chamber 105 is increased or the length L of the resonance tube 109 is increased. It is effective to lengthen the resonance frequency. Thus, by setting the volume V of the resonance chamber 105 or the length L of the resonance tube 109 to an optimum value, the resonance frequency can be obtained so as to obtain an exhaust noise reduction effect at a specific frequency. f is set, and normally, the length L of the resonance tube 109 is adjusted.

  However, since the resonance tube 109 of the conventional example 2 uses the cover 111 formed by press molding, it is necessary to newly manufacture the resonance tube 109 every time the length L of the resonance tube 109 is different. Further, in order to attach and fix the cover 111 to the outer peripheral surface of the exhaust pipe 107, it is necessary to provide a fixing margin portion a along the curvature of the outer peripheral surface of the exhaust pipe 107 on the outer peripheral edge of the cover 111. It is necessary to newly manufacture each time the pipe diameter is different. Accordingly, there is a problem that a new press mold is required for each different specification, resulting in high manufacturing costs.

  The problem to be solved by the present invention is to provide a muffler resonator structure that can improve the assembly workability without restricting the press-fitting direction of the plate to the exhaust pipe and can reduce the manufacturing cost. There is.

  In order to solve the above-mentioned problem, a resonator structure for a muffler according to claim 1, wherein a recess portion having a predetermined length along the longitudinal direction of the exhaust pipe is formed on a side wall of the exhaust pipe, and the one end side of the recess portion A resonance hole communicating with the inside of the exhaust pipe is formed, and the opening of the recess is closed by the closing plate so as to be within the outer arc of the exhaust pipe except for the end opposite to the resonance hole. It was set as the characteristic feature.

  In the muffler resonator structure of the present invention, as described above, the recess formed in the side wall of the exhaust pipe with a predetermined length along the longitudinal direction of the exhaust pipe, and the opening of the recess is opposite to the resonance hole. Since the resonance pipe is configured with a closing plate that closes in a state of being within the outer arc of the exhaust pipe, leaving the end side of the exhaust pipe, the press-fitting direction of the plate to the exhaust pipe is not restricted. As a result, it is possible to improve the assembly workability.

  In addition, since the closed plate is plate-shaped, it is easy to manufacture and is attached and fixed so that it fits within the outer arc of the exhaust pipe. The outer peripheral edge of the plate is fixed to the opening edge of the recess. Therefore, it is not necessary to change the shape of the mounting part even if the pipe diameter of the exhaust pipe is different, and if the length of the hollow part is formed longer, only the length of the blocking plate body is changed. The length of the resonance tube can be adjusted easily, so that the specific frequency to be reduced can be easily set and changed, and it is possible to easily and inexpensively respond to changes in specifications, thus reducing manufacturing costs. The effect that it becomes possible is obtained.

  Embodiments of the present invention will be described below with reference to the drawings.

The resonator structure for the muffler of this embodiment corresponds to the inventions described in claims 1 to 5.
First, a muffler resonator structure of this embodiment will be described with reference to the drawings.

  1 is an overall cross-sectional view showing a muffler resonator structure of this embodiment, FIG. 2 is an enlarged view taken along arrow A in FIG. 1, and FIG. 3 is an enlarged cross-sectional view taken along line BB in FIG. As shown, in this embodiment, the silencer chamber is formed by attaching the outer plates 2 and 3 to the front and rear ends of the laterally cylindrical outer shell 1 and closing the openings on both ends.

  The silencer chamber is partitioned by an inner plate (partition wall) 4 into a front (left side in FIG. 1) resonance chamber 5R and a rear (right side in FIG. 1) sound absorption chamber 5F. 3 and an exhaust pipe 6 through which exhaust from the engine circulates in a state of passing through the axial center portion of the inner plate 4.

  A large number of small holes 6a communicating with the sound absorbing chamber 5F are formed in the peripheral wall of the exhaust pipe 6 in the sound absorbing chamber 5F, and the sound absorbing chamber 5F is filled with a sound absorbing material 7 such as rock wool or glass wool. ing.

A recess 6b having a predetermined length along the longitudinal direction of the exhaust pipe 6 is formed on the side wall of the exhaust pipe 6 in the resonance chamber 5R.
This recess 6b communicates with the inside of the exhaust pipe 6 at the end of the recess 6b on the side of the notch 6c by recessing the recess 6b with the notch 6c circumferentially formed in the side wall of the exhaust pipe 6 as one end. Resonant holes 8 are formed.

  Then, the hollow portion 6b is closed by the flat closing plate body 9 with the opening of the hollow portion 6b remaining within the outer arc of the exhaust pipe 6 except for the end opposite to the resonance hole 8, thereby A resonance tube 10 having a resonance passage 10a between the closing plate 9 and the closing plate 9 is formed.

  In addition, the opening edge part of the hollow part 6b except the notch | incision part 6c forms the hollow step part 6d which can latch the obstruction board body 9, and attachment positioning of the obstruction board body 9 is made | formed, and exhaust_gas | exhaustion The closing plate body 9 is attached in a state where it falls within the outer arc of the tube 6. The closing plate 9 is attached by welding.

Next, the operation and effect of this embodiment will be described.
Since the muffler resonator structure of this embodiment is configured as described above, the annular space (resonance passage 10a) formed between the recess 6b formed in the exhaust pipe 6 and the closing plate 9 is cut off. The opening area of the resonance tube 10 is determined by the area, and the length L of the resonance tube 10 is determined by the length of the closing plate 9. By setting the length of the resonance tube 10 arbitrarily, the sound deadening The specific frequency range that can be determined can be arbitrarily determined.

  Therefore, in this embodiment, if the length of the recess 6b is formed longer, the length L of the resonance tube 10 can be easily adjusted by simply changing the length of the closing plate 9. The specific frequency to be reduced can be easily set and changed, and the closing plate 9 is flat and easy to manufacture, and is attached and fixed in a state of being accommodated within the outer arc of the exhaust pipe 6. Since it is sufficient to fix the outer peripheral edge portion of the plate body to the opening edge portion of the recess portion 6b, it is not necessary to change the shape of the mounting portion even if the pipe diameter of the exhaust pipe 6 is different.

  Therefore, it is possible to easily and inexpensively respond to a change in specifications, and an effect is obtained that the manufacturing cost can be reduced.

  Further, a recess 6b formed in a predetermined length along the longitudinal direction of the exhaust pipe 6 on the side wall of the exhaust pipe 6 and an opening of the recess 6b leaving the end opposite to the resonance hole 8 are left. By forming the resonance pipe 10 with the closing plate body 9 that is closed in a state of being accommodated within the outer arc of the exhaust pipe 6, the press-fitting direction of the outer plates 2, 3 and the inner plate 4 with respect to the exhaust pipe 6 is restricted. As a result, it is possible to improve the assembly workability.

  Further, by forming the recessed step 6d that can lock the closing plate 9 at the opening edge of the recessed portion 6b, the closing position of the closing plate 9 can be mounted and the workability can be improved. The closing plate 9 can be attached in a state of being accommodated in the outer arc of the tube 6.

  Although the present embodiment has been described above, the present invention is not limited to the above-described embodiment, and design changes and the like within a scope not departing from the gist of the present invention are included in the present invention.

  For example, in the embodiment, the recess 6b is recessed with the notch 6c inserted in the side wall of the exhaust pipe 6 in the circumferential direction as one end, thereby communicating with the inside of the exhaust pipe 6 at the end of the recess 6b on the side of the notch 6c. Although the resonance hole 8 is formed, the recess 6b may be formed without forming the notch 6c, and may be formed at the bottom on one end side of the recess 6b.

  In the embodiment, the closing plate 9 is formed of a flat plate. However, the closing plate 9 may have a circular arc shape as long as it falls within the outer arc of the exhaust pipe 6.

It is a whole sectional view showing the resonator structure for a muffler of an example. It is A arrow enlarged view of FIG. It is an expanded sectional view in the BB line of FIG. It is a whole sectional view showing a resonator structure for a muffler of Conventional Example 1. It is a top view of the principal part which shows the resonator structure for mufflers of the prior art example 2. It is a side view of the principal part which shows the resonator structure for mufflers of the prior art example 2. It is sectional drawing in the CC line of FIG.

DESCRIPTION OF SYMBOLS 1 Outer shell 2 Outer plate 3 Outer plate 4 Inner plate 5F Sound absorption chamber 5R Resonance chamber 6 Exhaust pipe 6a Small hole 6b Recessed part 6c Notch 6d Recessed step part 7 Sound absorbing material 8 Resonant hole 9 Closed plate 10 Resonant path 10a Resonant passage

Claims (5)

A depression having a predetermined length along the longitudinal direction of the exhaust pipe is formed on the side wall of the exhaust pipe,
A resonance hole communicating with the inside of the exhaust pipe is formed on one end side of the recess,
The muffler resonator structure is characterized in that the opening of the recess is closed by a closing plate so as to be within the outer arc of the exhaust pipe except for the end opposite to the resonance hole.   The muffler resonator structure according to claim 1, wherein the closing plate is formed of a flat plate.   3. The muffler resonator structure according to claim 1, wherein a recessed step portion capable of engaging the closing plate is formed at an opening edge of the recessed portion. 4.   The muffler resonator structure according to any one of claims 1 to 3, wherein the resonance hole is formed in a bottom portion of the hollow portion.   The resonator structure for a muffler according to any one of claims 1 to 3, wherein the resonance hole has a cut formed in a circumferential direction in a side wall of the exhaust pipe as one end portion, and is cut by opening the hollow portion. A muffler resonator structure characterized by being formed.

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