JPH06235310A - Muffler having inlet pipe - Google Patents

Abstract

PURPOSE:To loosen ignition of a muffler while facilitating manufacture by composing an inlet pipe of the muffler of a flat plate serving as flange which has an outer end provided with an exhaust inflow port and an inner end provided with an exhaust outflow port, and a shute-like press molded member which forms an exhaust passage, and then projecting a bracket to be welded onto the muffler. CONSTITUTION:A muffler 1 has a muffler body 2 and an inlet pipe 3 penetrating its peripheral wall 2a. The inlet pipe 3, being composed of a flat plate serving as flange 4 and a chute-like press molded member 5, is connected to an exhaust pipe 6 by means of flanges 4a, 5a. An exhaust inflow port 4b, exhaust outflow ports 4c and 4d are previously punched by drilling. A bent bracket 4e is projected on an inner end portion of the flat plate serving as flange 4, and welded onto a flat portion 2b of the muffler body 2. It is thus possible to dispense with a blank plug which is conventionally necessary, and facilitate punching operation. Ignition in engine operation is loosened because no pocket is formed, from which heat is hard to escape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a muffler as an exhaust silencer installed in an engine exhaust system,
The present invention relates to a muffler with an inlet pipe equipped with an inlet pipe for introducing exhaust gas.

[0002]

2. Description of the Related Art As such a muffler with an inlet pipe, as shown in FIGS. 8A and 8B, a muffler body a formed in a cylindrical shape with both ends closed and a peripheral wall portion of the muffler body a. The one provided with a steel pipe inlet pipe c which is inserted and fixed in the muffler body a through b is conventionally known (see Japanese Utility Model Laid-Open No. 2-139317). Here, a flange e for connecting to an exhaust pipe rear end (not shown) of the engine exhaust system is welded and fixed around the exhaust inflow hole d opened at the outer end of the inlet pipe c, and the muffler body is also provided. An exhaust outflow hole f is formed in the inner peripheral surface of the inlet pipe c facing the inside of a, and a blind plug g for closing the exhaust outflow hole f is fixedly fitted in the inner end opening. Such an inlet pipe c is hermetically welded and fixed to the surrounding wall portion b through which the inlet pipe c penetrates, and the blind plug g is abutted against the inner surface of the surrounding wall portion b of the muffler body a to be plug-welded. As a result, it is integrally connected to the muffler body a.

[0003]

However, the above-mentioned conventional example has various problems as described below. Since the inlet pipe c is simply made of steel and both ends are open, the inner end opening of the inlet pipe c facing the muffler body a must be closed by the blind plug g, which increases the number of parts and the number of working steps. Therefore, the cost becomes higher. Since the inlet pipe c is made of a steel pipe, the exhaust gas outflow hole f must be bored from the outer peripheral surface of the curved inlet pipe c by drilling or the like, and its workability is poor. If the inlet pipe c is straight, the muffler body a
Since it largely projects rearward from the exhaust pipe end of the engine exhaust system (not shown), the inlet pipe c must be bent so that the muffler body a is located on the side of the exhaust pipe rear end. The bending process of the inlet pipe c is limited in terms of curvature and cannot be rapidly bent at a single location due to a small radius of curvature, so bending is performed at a plurality of locations, which increases the number of bending processes. Moreover, the bending of the inlet pipe c requires a certain radius of curvature.
Only one inlet pipe c extends from the end of the exhaust pipe to the rear thereof. The inner end opening of the inlet pipe c is closed by a blind plug g, and a bag-shaped portion that easily retains heat is formed between it and the exhaust outflow hole f. g easily becomes abnormally high in temperature, and the muffler body a plug-welded to this easily becomes high in temperature and easily becomes red hot.

In view of the above, the present invention does not require a blind plug in the manufacturing process and facilitates the drilling work of the exhaust outflow hole, and the position of the muffler body can be easily adjusted in the pipe length direction of the inlet pipe and the assembly to the engine exhaust system. In the state, the muffler body and the inlet pipe do not largely project from the end of the exhaust pipe, and an object is to provide a muffler with an inlet pipe that can mitigate the tendency of the muffler body to become red heat during engine operation. .

[0005]

To this end, according to the present invention, a cylindrical muffler body of which both ends are closed penetrates a peripheral wall portion in an airtight state, and an inner end portion is fixed to an inner periphery of the muffler body, and In an muffler with an inlet pipe having an inlet pipe whose end is connected to an exhaust pipe end of an engine exhaust system via a flange, the inlet pipe has an exhaust inflow hole perforated at an outer end and an inner end at an inner end. An exhaust passage extending from the exhaust inflow hole to the exhaust outflow hole is formed between the flat plate member also serving as a flange having the exhaust outflow hole and the peripheral edge portion of the flat plate member also serving as the flange are airtightly welded to each other. The basic means is to provide a bracket portion for welding and fixing to the peripheral wall portion of the muffler body at the inner end of the flat plate member that also serves as a flange.

Here, the flat plate member serving also as the flange is
You may press-form the curved cross-section part which expands the passage cross-sectional area of the exhaust passage between it and the gutter-shaped press-forming member.

The bracket portion is bent at its tip to be welded and fixed to the inner surface of the peripheral wall portion of the muffler body, or penetrates the peripheral wall portion of the muffler body and is airtightly welded and fixed thereto, and further the peripheral wall of the muffler body. They may be fixed together by caulking at the joints.

[0008]

The muffler with an inlet pipe of the present invention, which employs the above-mentioned basic means, is a flange-use flat plate member having an exhaust inflow hole and an exhaust outflow hole, and a flange-use flat plate which is hermetically welded at its peripheral edge. The inlet pipe is composed of a gutter-shaped press-formed member that forms an exhaust passage between the member and the member, and is necessary in the case of the conventional steel pipe-made inlet pipe and does not require a plug for manufacturing.

Further, since the exhaust gas inflow hole and the exhaust gas outflow hole of the inlet pipe may be formed in the flat plate-shaped flange / flat plate member by an appropriate means such as drilling or punching, they are curved as in the prior art. The drilling operation is much easier than drilling from the outer peripheral surface of the steel pipe.

Further, the inlet pipe has a structure in which the inner end portion facing the inside of the muffler body is welded and fixed to the peripheral wall portion of the muffler body via the bracket portion projecting from the inner end portion of the flat plate member also serving as a flange. By appropriately setting the protruding length of the bracket portion, the position of the muffler body can be easily adjusted in the pipe length direction of the inlet pipe.

The muffler with an inlet pipe of the present invention is assembled in an engine exhaust system by connecting a flange-combined flat plate member constituting the inlet pipe to the end portion of the exhaust pipe. Then, the inlet pipe consisting of the flat plate member also serving as the flange and the gutter-shaped press-formed member welded thereto is bent substantially at right angles to the side of the exhaust pipe end without being overhanging greatly.

Further, in the muffler with an inlet pipe of the present invention, the exhaust passage of the inlet pipe formed between the flat plate member also serving as the flange and the gutter-shaped press forming member extends from the exhaust inflow hole to the exhaust outflow hole. Since there is no bag-like part on the exhaust outlet hole side where heat can easily accumulate, the inlet pipe and bracket will not become abnormally hot due to the heat of the exhaust gas during engine operation, and will therefore be fixed to the bracket by welding. The tendency of the muffler body to become red-heated is alleviated.

[0013]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. 1A and 1B show a first embodiment of a muffler 1 with an inlet pipe according to the present invention, which penetrates a cylindrical muffler body 2 with both ends closed and a peripheral wall portion 2a of the muffler body 2. Inlet pipe 3
The inlet pipe 3 has a portion penetrating the peripheral wall portion 2a that is hermetically welded and fixed to the peripheral wall portion 2a over the entire circumference.

The inlet pipe 3 is composed of a flat plate member 4 also serving as an elongated flange, and an elongated gutter-shaped press-molded member 5 joined to one side surface of the flat plate member 4 serving also as a flange and hermetically welded at its peripheral edge. The flange portions 4a and 5a connected to the flange 6a at the end of the exhaust pipe 6 in the engine exhaust system are integrally formed at the outer ends of the flat plate member 4 also serving as the flange and the gutter-shaped press-formed member 5, respectively. Has been done. In addition, the flange portions 4a and 5a
For the exhaust system of a small engine such as a general-purpose engine, may be attached to the exhaust port outlet of the cylinder. Further, an exhaust gas inflow hole 4b communicating with the exhaust pipe 6 is formed at the outer end portion of the flat plate member 4 also serving as a flange, and an exhaust gas outflow communicating with the inside of the muffler body 2 is located at the inner end portion. Holes 4c and 4d are formed. The exhaust gas outflow holes 4c and 4d are open toward the inner surface of the peripheral wall portion 2a of the muffler body 2.

The exhaust inflow hole 4b and the exhaust outflow hole 4
Numerals c and 4d are preliminarily punched in the flange-cum-flat plate member 4 by an appropriate processing means such as drilling or punching. By covering these with the gutter-shaped press-molding member 5, the flange-cum-flat plate member 4 and Gutter-shaped press-formed member 5
An exhaust passage 7 extending from the exhaust inflow hole 4b to the exhaust outflow hole 4d is formed between and.

Further, at the inner end of the flat plate member 4 which also serves as a flange, a bracket portion 4e is integrally provided so as to be bent and bent at its tip end into an L shape. A flat portion 2b is formed on the peripheral wall portion 2a of the muffler body 2 so as to be surface-bonded to the tip portion of the bracket portion 4e, and the flat portion 2b and the bent tip portion of the bracket portion 4e are mutually joined by plug welding. It is fixed by welding.

In the muffler 1 with the inlet pipe of the first embodiment thus constructed, the flange portion 4a of the flat plate member 4 serving also as the flange constituting the inlet pipe 3 has the exhaust pipe 6
By being connected to the flange 6a at the end portion, the inlet pipe 3 is bent from the end portion of the exhaust pipe 6 and extends at a substantially right angle, and the muffler body 2 is disposed laterally to the end portion of the exhaust pipe 6. In such an assembled state in the exhaust system, the inlet pipe 3 only protrudes from the end portion of the exhaust pipe 6 by the thickness equivalent amount L2, and the end portion of the exhaust pipe 6 as in the conventional example shown in FIG. Does not overhang from the department. Therefore, the muffler 1 with the inlet pipe is reasonably arranged in the limited installation space.

During engine operation, the exhaust gas discharged from the exhaust pipe 6 flows into the exhaust passage 7 in the inlet pipe 3 from the exhaust inflow hole 4b and passes through the exhaust passage 7 to the exhaust outflow hole 4c. , 4d into the muffler body 2. At that time, since the bag-shaped portion where heat is easily accumulated is not formed in the exhaust passage 7 on the exhaust outflow hole 4d side, the inlet pipe 3 and the bracket portion 4e are not abnormally heated by the heat of the exhaust gas. Therefore, the bracket portion 4e
The muffler body 2 that is welded and fixed to is prevented from being inadvertently turned red.

On the other hand, in terms of manufacturing, the muffler 1 with the inlet pipe of the first embodiment has a flat plate member 4 serving also as a flange having an exhaust gas inflow hole 4b and exhaust gas outflow holes 4c, 4d.
Since the inlet pipe 3 is composed of the gutter-shaped press-molded member 5 that forms the exhaust passage 7 by welding the peripheral edge portion to the flat plate member 4 that also serves as the flange so as to cover them,
Since the conventional steel pipe-made inlet pipe c shown in FIG. 8 requires the plug g, which is unnecessary, the cost can be reduced by reducing the number of parts and the number of working steps.

Further, the exhaust gas inflow hole 4 of the inlet pipe 3
The b and the exhaust gas outflow holes 4c and 4d may be formed in the flat plate-shaped flange / flat plate member 4 by an appropriate means such as drilling or punching. The drilling operation is much easier than machining.

Further, in the muffler 1 with the inlet pipe of the first embodiment, the muffler is changed by changing the bending portion of the bracket portion 4e projecting from the inner end of the flat plate member 4 serving also as the flange which constitutes the inlet pipe 3. The position of the body 2 is slightly adjusted along the axial direction of the inlet pipe 3. For example, as shown in FIG. 2A, if the bending portion of the bracket portion 4e is set on the tip side and the bending amount of the tip portion is reduced to L3, the muffler body 2 extends along the inlet pipe 3 and the inside thereof. The position is adjusted slightly toward the end, and on the contrary,
As shown in (b), if the bending portion of the bracket portion 4e is set to the proximal end side and the bending amount of the distal end portion is increased to L4, the muffler body 2 is moved along the inlet pipe 3 to the outer end side thereof. The position is adjusted slightly. Therefore, even if there is some error in the installation space of the muffler body 2, this can be dealt with.

The tip of the bracket portion 4e of the muffler 1 with the inlet pipe of the first embodiment is shown in FIG.
As shown in FIG. 5, the muffler body 2 may be bent in an arc shape along the inner surface of the peripheral wall portion 2a, and by doing so, it is not necessary to form the flat portion 2b on the peripheral wall portion 2a.

Further, the exhaust outflow holes 4c and 4d in the muffler 1 with the inlet pipe can be replaced with these and have an appropriate shape and number. For example, in FIG.
A trapezoidal exhaust outflow hole 4f as shown in FIG.
The exhaust gas outlet hole 4g may have an elliptical shape as shown in (b), or three circular exhaust gas outlet holes 4h as shown in FIG. 4 (c) and a circular exhaust gas outlet hole 4g as shown in FIG. 4 (d). One exhaust outlet 4i may be provided.

FIGS. 5 (a) and 5 (b) show a bracket portion 4e projecting from the flat plate member 4 serving also as a flange and the muffler body 2 in the muffler 1 with the inlet pipe of the first embodiment.
Of the present invention in which the welding fixing structure with the peripheral wall portion 2a of the
An example is shown. In the second embodiment, the bracket portion 4e is a straight tongue-shaped bracket portion 4j.
Correspondingly, a slit 2c is formed in the peripheral wall portion 2a for inserting the tip portion of the bracket portion 4j. The bracket portion 4j is hermetically welded and fixed over the entire circumference in a state where the bracket portion 4j is inserted into the slit 2c, and the bracket portion 4 protruding outward from the peripheral wall portion 2a.
The tip of j is cut or bent along the outer surface of the peripheral wall 2a.

In the second embodiment, the amount of insertion of the bracket portion 4j into the slit 2c of the peripheral wall portion 2a, that is, the amount of protrusion of the tip of the bracket portion 4j protruding outward from the peripheral wall portion 2a is appropriately adjusted to be increased or decreased. By welding and fixing the portion 4j to the peripheral wall portion 2a, the position of the muffler body 2 is slightly adjusted along the axial direction of the inlet pipe 3.

FIG. 6 shows a third embodiment of the present invention in which the exhaust passage 7 in the muffler 1 with the inlet pipe of the first embodiment is modified so as to be expanded. In the third embodiment, the flat plate member 4 serving also as the flange is, for example, as shown in FIG.
The exhaust outflow hole 4i as shown in (d) is provided, and the flat plate member 4 also serving as the flange is press-formed with a curved cross-section 4k at a portion excluding the flange 4a and the bracket 4e. The curved cross-section 4k expands the passage cross-sectional area of the exhaust passage 7 formed between it and the gutter-shaped press-molded member 5. In the third embodiment,
With the expansion of the passage cross-sectional area of the exhaust passage 7, the exhaust outlet hole 5b is provided in the trough-shaped press-molded member 5 in addition to the exhaust outlet hole 4i of the flat plate member 4 also serving as the flange.
This exhaust outflow hole 5b is not essential.

FIGS. 7 (a) and 7 (b) show the present invention provided with a muffler body 9 which is formed into a rectangular tube shape with both ends closed by body halves 9a and 9b which are joined by crimping vertically with the element 8 interposed therebetween. 4 shows a fourth embodiment of the present invention. Here, the inlet pipe 3 is constructed in the same manner as the inlet pipe 3 in the second embodiment shown in FIGS. 5A and 5B, and is provided at the inner end portion of the flange-combined flat plate member 4 which is a constituent member thereof. Is provided with a straight tongue-shaped bracket portion 4j. The inlet pipe 3 having the flat plate member 4 also serving as the flange passes through the peripheral wall portion 9c of the half body 9a in a direction in which the exhaust outflow holes 4c and 4d face the element 8 and open, and the inner end portion thereof is provided. The protruding bracket part 4
The tip of j is sandwiched between the crimp joints 9d of the body halves 9a and 9b and fixed together. The portion of the inlet pipe 3 that penetrates the peripheral wall portion 9c of the half body 9a is hermetically welded and fixed to the peripheral wall portion 9c over the entire circumference.

In the fourth embodiment, the bracket portion 4j is fastened together with the caulking joint portion 9d of the body halves 9a and 9b, so that the plugs required in the first to third embodiments. No need for welding work. Further, since the exhaust gas outflow holes 4c and 4d of the inlet pipe 3 are opened so as to face the element 8, the exhaust gas during engine operation does not directly hit the peripheral wall portion 9c of the muffler body 9,
The red heat tendency of the muffler body 9 is further alleviated.

[0029]

As described above, according to the present invention, there is provided a flange-combined flat plate member having an inlet pipe having an exhaust gas inflow hole and an exhaust gas outflow hole, and a flange-combined flat plate member having a peripheral edge welded to this. Because of the relationship with the gutter-shaped press forming member that forms the exhaust passage between the two, it is possible to eliminate the need for the bulkhead plug in manufacturing, which is necessary in the case of the conventional steel pipe inlet pipe.

Further, the exhaust inflow hole and the exhaust outflow hole of the inlet pipe may be formed in a flat plate-shaped flange / flat plate member by appropriate means such as drilling or punching, so that they have curved surfaces as in the prior art. The drilling operation is much easier than drilling from the outer peripheral surface of the steel pipe.

Further, the inner end portion of the inlet pipe which penetrates the peripheral wall portion of the muffler body and faces the inside thereof is welded to the peripheral wall portion of the muffler body through a bracket portion projecting from the inner end portion of the flat plate member serving also as a flange. Because it is a fixed structure,
By appropriately setting the protruding length of the bracket portion, the position of the muffler body can be easily adjusted in the pipe length direction of the inlet pipe.

Here, in a state where the exhaust pipe is assembled to the engine exhaust system, the inlet pipe composed of a flat plate member serving also as a flange connected to the end of the exhaust pipe and a gutter-shaped press-formed member welded to the flange is an exhaust pipe end. It is possible to avoid a situation in which the inlet pipe and the muffler body greatly extend from the end portion of the exhaust pipe because they bend and extend from the portion to the side at a substantially right angle.

Further, the exhaust passage of the inlet pipe formed between the flat plate member also serving as the flange and the gutter-shaped press forming member extends from the exhaust inflow hole to the exhaust outflow hole, and heat is trapped on the exhaust outflow hole side. Since the bag does not easily form a bag-shaped part, the inlet pipe and bracket will not become abnormally hot due to the heat of the exhaust gas even during engine operation. Therefore, the muffler body welded and fixed to the bracket will be operated by the engine. It can reduce the red heat inside.

[Brief description of drawings]

1A and 1B show a first embodiment of the present invention, in which FIG. 1A is a lateral sectional view and FIG.

2A and 2B are cross-sectional views showing the operation of the first embodiment, respectively.

FIG. 3 is a cross-sectional view showing a modified example of the first embodiment.

4 (a), (b), (c), and (d) are cross-sectional views of an exhaust pipe terminal portion showing a modification of the first embodiment.

5A and 5B show a second embodiment of the present invention, FIG. 5A is a lateral sectional view, and FIG.

FIG. 6 is a transverse sectional view showing a third embodiment of the present invention.

FIG. 7 shows a fourth embodiment of the present invention, (a) is a side view,
(B) is a cross-sectional view.

8A and 8B show a conventional example, FIG. 8A is a plan view with a partial horizontal cross section, and FIG. 8B is a side view with a partial vertical cross section.

[Explanation of symbols]

 1 muffler with inlet pipe 2 muffler body 2a peripheral wall portion 2b flat portion 3 inlet pipe 4 flat plate member also serving as flange 4a flange portion 4b exhaust gas inlet holes 4c, 4d, 4f, 4g, 4h, 4i exhaust gas outlet holes 4e, 4j bracket portion 4k curved Cross-section 5 Gutter-shaped press forming member 5a Flange 5b Exhaust outflow hole 6 Exhaust pipe 6a Flange 7 Exhaust passage 8 Element 9 Muffler body 9a, 9b Body half 9c Circumferential wall 9d Caulking joint

Claims (5)

[Claims] 1. A cylindrical muffler body is pierced through a peripheral wall portion in an airtight state, an inner end portion is fixed to an inner periphery of the muffler body, and an outer end portion is connected to an exhaust port end portion of an engine exhaust system via a flange. In the muffler with an inlet pipe provided with an inlet pipe connected to each other, the inlet pipe has a flat plate member also serving as a flange, in which an exhaust inflow hole is formed at an outer end portion and an exhaust outflow hole is formed at an inner end portion, and the flange. A flange-shaped flat plate member having a gutter-shaped press-molded member, the peripheral portion of which is hermetically welded to a dual-purpose flat plate member to form an exhaust passage extending from the exhaust inflow hole to the exhaust outflow hole between the flange and flat plate member. A muffler with an inlet pipe, characterized in that a bracket portion which is welded and fixed to a peripheral wall portion of a muffler body is provided at an inner end portion of the member. 2. The flat plate member also serving as a flange is press-molded with a curved cross-section portion for expanding a passage cross-sectional area of an exhaust passage between the flat plate member and the gutter-shaped press-molding member.
Muffler with the described inlet pipe. 3. The muffler with an inlet pipe according to claim 1, wherein the bracket portion is bent at its tip and is welded and fixed to the inner surface of the peripheral wall portion of the muffler body. 4. The muffler with an inlet pipe according to claim 1, wherein the bracket portion penetrates a peripheral wall portion of the muffler body and is hermetically welded and fixed thereto. 5. The muffler with an inlet pipe according to claim 1, wherein the bracket portion is fastened and fixed together with a caulking joint portion of a peripheral wall portion of a muffler body.