JPH0221541Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is mainly used in small engines, and relates to a muffler equipped with a spark arrester that captures carbon mixed with exhaust gas and discharged to the outside.

[Prior Art] Currently, in small engines such as general-purpose agricultural engines, carbon is stored inside the muffler to prevent large carbon particles mixed in the exhaust from turning into sparks and being discharged from the muffler. A spark arrester is installed to capture the spark. According to the regulations of some countries, this spark arrester is
The ability to effectively capture carbon particles with a diameter of 0.58 mm or more is required.

However, the spark arrester described above tends to become clogged with captured carbon, so it is necessary to clean it frequently. Therefore, conventional spark arresters are known in which the spark arrester can be easily attached and detached from the muffler body. One example is the technique described in Japanese Utility Model Application Publication No. 127811/1983.

This prior art aims to capture carbon by arranging an exhaust outlet pipe inside the muffler body and inserting a wire mesh inside a cylindrical reinforcing frame that constitutes the exhaust outlet pipe to form a spark arrester. It's on. Also,
Insert a male mounting screw from the axially inner side of the end plate into the insertion hole provided in the end plate (lid) at one end of the frame, and insert it into the inner surface of the frame beyond the head of the male screw. A protrusion located inward in the axial direction is provided, and this protrusion prevents the male thread from falling off in the axial direction.Thereby, by simply tightening or loosening the male thread, the exhaust outlet is closed. By making the pipe removable, it is easy to attach and detach the exhaust outlet pipe.

[Problems to be solved by the invention] However, in the above-mentioned prior art, a part of the wire mesh is covered by the cylindrical frame, which reduces the exposed surface area of the wire mesh and reduces the ability to capture carbon. .

In addition, the male screw inserted into the end plate is prevented from coming out by a protrusion provided on the frame to which this end plate is welded, so after welding the end plate to the frame, insert the male screw into the insertion hole of the end plate. Because it cannot be inserted,
When manufacturing an exhaust outlet pipe, it is necessary to first attach a male thread to an end plate, and then weld this end plate to the frame. Therefore, after the end plate is press-formed and before welding, in other words, the process of attaching the male screw to the end plate is inserted into the series of sub-assembly processes that lead from press-forming to welding, and the exhaust outlet The tube manufacturing process becomes complicated. Furthermore, the male threads become an obstacle during welding, reducing welding workability.

This invention was made to solve the above-mentioned conventional problems, and aims to provide a muffler with a spark arrester that can effectively capture carbon and is easy to manufacture.

[Means for Solving the Problems] In order to achieve the above object, this invention first connects an exhaust outlet pipe to a cylindrical arrester body and a lid (an end) fixed to one end of the arrester body. board)
and a cylindrical cap fixed to the other end of the arrester main body. An insertion hole is formed in the lid body, and a male screw is inserted into the insertion hole from inside the lid body, and the male screw is screwed into a female screw provided in the muffler body. It is attached to the muffler body. On the other hand, the cap is provided with a protrusion that expands radially outward, and by abutting the protrusion against the inner peripheral surface of a cylindrical guide member provided on the muffler body, the cap can be It is attached to the muffler body. In this way, the exhaust outlet pipe is detachably attached to the muffler body via the lid and the cap.

[Operation] According to this invention, since the arrester body made of wire mesh is not covered with a frame, the exposed surface area of the wire mesh becomes large.

In addition, although the exhaust outlet pipe does not have a frame that also serves as an attachment member to the muffler body, both ends of the exhaust outlet pipe are attached to the muffler body via a lid and a cap, respectively. Strongly supported.

Furthermore, since the other end of the exhaust outlet pipe is supported by the muffler body by a protrusion provided on the base, the centering action of the protrusion allows accurate centering between the base and the guide member. . Therefore, even though the dimensional accuracy of the arrester body made of wire mesh is low, the gap between the outer periphery of the cap and the inner periphery of the guide member can be kept small, and carbon particles can be prevented from flowing out from this gap. can be prevented. Furthermore, in manufacturing the exhaust outlet pipe, the male screw can be inserted into the insertion hole of the lid after the subassembly of joining the arrester body to the lid is completed.

[Example] Hereinafter, an example of this invention will be described with reference to the drawings.

In FIG. 1, the muffler 10 is a muffler main body 11
and a muffler cover 12. A collar 13 having a female thread is fixed to the muffler main body 11, and the muffler cover 12 is fixed to the muffler main body 11 by fastening the muffler cover 12 to the collar 13 with bolts 14. The muffler cover 12 is fixed to an engine body (not shown).

The entrance of the muffler main body 11 is an exhaust introduction pipe 17
It communicates with an exhaust manifold (not shown) through the muffler body 11, and an exhaust outlet pipe 19 of this invention is provided at the outlet, located inside the muffler body 11. Further, inside the muffler main body 11, a partition wall 22 having a communication hole 21 and a mounting member 24 having a female thread 23 are fixed.

The exhaust outlet pipe 19 is configured to be detachably attached to the muffler body 11 by a structure described later, and as shown in FIG. Main body 2
6, and a cylindrical base 28 fixed to the other end (right end) of the arrester main body 26. The lid body 27 and the cap 28 are fixed to the arrester body 26 by brazing or welding. As shown in FIG. 3, the arrester main body 26 is made by bending a flat wire mesh into a cylindrical shape and fixing both ends thereof by brazing 29.

The lid body 27 is provided with an insertion hole 31 as shown in FIG. The cover body 27, that is, one end (left end) of the exhaust outlet pipe 19, is attached to the muffler body 11 by screwing into the female thread 23 of the mounting member 24 provided on the muffler body 11.

An engagement groove 33 having a diameter d smaller than the outer diameter D of the threaded portion 32a is formed in the lower part of the neck of the male screw 32 shown in FIG.
The screw seat surface 34 around the screw seat surface 34 is formed in a conical shape that protrudes axially inward (rightward), and the inner diameter D1 of the insertion hole 31 is set to the threaded portion 32a of the male screw 32.
(Outline D) is the minimum diameter that can be passed through. Thereby, the male screw 32 is inserted into the insertion hole 31, and
When the female thread 23 of the mounting member 24 shown in FIG. The inner peripheral edge thereof is adapted to be irremovably engaged with the engagement groove 33 in the axial direction 36.

As shown in FIG. 2, the cap 28 is provided with a plurality of notches 37 along the axial direction 36, and the portion located between these notches 37 is
As shown in the figure, by bending radially outward 38, a protruding piece 39 that expands radially outward is formed. Further, a cylindrical guide member 42 is fixed to the through hole 41 provided at the outlet of the muffler body 11, and by abutting the protruding piece 39 of the mouthpiece 28 on the inner peripheral surface of the guide member 42, Base 2
8, that is, the other end (left end) of the exhaust outlet pipe 19
is attached to the muffler body 11.

Next, the procedure for attaching and removing the exhaust outlet pipe 19 to the muffler body 11 will be explained.

First, when attaching the exhaust outlet pipe 19 of FIG. 2 to the muffler body 11 of FIG. 1, the male screw 32 is inserted into the insertion hole 31 of the lid body 27 of FIG. 19 into the muffler body 11 through the opening 43 of the muffler cover 12 and the guide member 42 of the muffler body 11 in FIG. One end is fixed to the muffler body 11. At this time, as mentioned above, the conical screw bearing surface 34 shown in FIG.
The insertion hole 31 is pressed against the mounting member 24 in FIG.
irremovably engages with.

On the other hand, the base 28 at the other end of the exhaust outlet pipe 19 is
The projecting piece 39 is fixed to the guide member 42 by being brought into contact with the inner circumferential surface of the guide member 42 .

Next, when the exhaust outlet pipe 19 is clogged and the exhaust outlet pipe 19 is to be removed from the muffler body 11 in order to be cleaned, the male screw 32 is first loosened. Male thread 3
2 is engaged with the lid body 27 as described above,
As the male thread 32 separates from the female thread 23,
The lid body 27 , that is, one end of the exhaust outlet pipe 19 separates from the female thread 23 , and the base 28 , that is, the other end of the exhaust outlet pipe 19 , connects to the guide member 42 of the muffler body 11 and the opening of the muffler cover 12 . 4
Go out through 3. By pulling out the other end of the exhaust outlet pipe 19 that has come out to the outside, the exhaust outlet pipe 19 is completely connected to the muffler main body 11.
extract it from

In this way, the exhaust outlet pipe 19 can be attached and detached from the muffler body 11 only by tightening and loosening the male screw 32, and there is no need to remove other parts of the muffler 10. is easy. Further, by loosening the male screw 32, the other end of the exhaust outlet pipe 19 automatically comes out of the muffler body 11, so that the exhaust outlet pipe 19 can be easily removed. Moreover, since the male screw 32 is engaged with the lid 27 and will not fall off from the lid 27, the work of attaching and removing the exhaust outlet pipe 19 is facilitated from this point of view as well. Note that the above-mentioned prior art also provides such ease of attachment and detachment.

In the above configuration, the exhaust gas from the engine is
The exhaust gas is introduced into the muffler body 11 from the exhaust introduction pipe 17 and is muffled, and the arrester body 26 of the exhaust outlet pipe 19
After carbon particles are captured, they are discharged to the outside. Here, the exhaust outlet pipe 19 made of wire mesh
Since it is not covered with a frame like in the past, the exposed surface area of the wire mesh is large. Therefore,
Carbon can be captured effectively.

Further, the exhaust outlet pipe 19 has both ends connected to the muffler main body 11 through the lid body 27 and the base 28, respectively.
Since it is attached to the muffler body 11, it is firmly supported by the muffler body 11 even though it does not have a frame body that also serves as a mounting member to the muffler body as in the conventional case. Therefore, there is no risk that the exhaust outlet pipe 19 will vibrate and hit the muffler body 11 due to engine vibration.

Here, if the other end (right end) of the arrester main body 26 is not provided with the base 28 and the other end of the arrester main body 26 is inserted into the guide member 42 as it is, the dimensional accuracy of the wire mesh is extremely low, so the arrester It is necessary to design the outer diameter of the main body 26 to be smaller than the inner diameter of the guide member 42 by 1.5 mm or more.
Therefore, a large gap is created between the outer periphery of the arrester body 26 and the inner periphery of the guide member 42.
The diameter that must not be discharged from between
There is a problem where large carbon particles larger than 0.58 mm leak out.

However, in the exhaust outlet pipe 19 of this invention, the cap 28 is fixed to the other end.
Since the dimensional accuracy of the outer diameter D2 (see FIG. 2) can be higher than that of a wire mesh, the dimensional difference between the outer diameter D2 of the cap 28 and the inner diameter of the guide member 42 can be reduced to 1 mm or less. Moreover, the protrusion 3 provided on the cap 28
9, self-alignment is achieved and the accuracy of centering between the cap 28 and the guide member 42 is improved. As a result, even if the outer diameter D2 of the cap 28 is at most 1 mm smaller than the inner diameter of the guide member 42, the distance between the outer circumference of the cap 28 and the inner circumference of the guide member 42 is reduced by 0.5 mm.
It can be made as small as possible. Therefore, the base 28
There is no risk of large carbon particles with a diameter of 0.58 mm or more flowing out from between the guide member 42 and the guide member 42.

Furthermore, when manufacturing the exhaust outlet pipe 19 itself shown in FIG.
and the cap 28 are joined by brazing or welding, and then the male screw 32 is inserted into the insertion hole 31 of the lid body 27.
Just insert it into. In other words, after completing a series of sub-assembly steps from the machining process of the lid body 27 to the joining process, the male screw 32 can be attached to the lid body 27 when assembling the entire muffler 10. The manufacturing process of No. 19 itself is simplified. Furthermore, since the lid body 27 through which the male thread 32 is not inserted is joined to the arrester main body 26, the male thread 32 does not get in the way during joining, and the joining work becomes easy.

FIG. 5 shows a second embodiment of this invention, in which the lid body 27 and the base 28 are connected to the arrester body 2.
6 by brazing or welding. This second embodiment also has the same effects as the first embodiment.

FIG. 6 shows a third embodiment, in which an engagement groove 33 having a diameter d smaller than the outer diameter D of the threaded portion 32a is also formed in the lower part of the neck of the male thread 32. The inner diameter D1 of the insertion hole 31 is set to a dimension that allows the threaded portion 32a of the male screw 32 to pass through it smoothly. A clip 51 having a shape shown in FIG. 7 is engaged with the engagement groove 33 of the male screw 32 inserted into the insertion hole 31 from the outside of the lid 27. Male thread 3
2 is prevented from coming off from the insertion hole 31.
The structure of the portion of the exhaust outlet pipe 19 that is not shown in FIG. 6 is the same as that of the first embodiment shown in FIG.

This third embodiment also has the same effects as the first embodiment.

In each of the above embodiments, the notch 37 and the protrusion 39 are provided in advance in the cap 28 shown in FIG. 2, and the cap 28 is fixed to the arrester body 26, but unlike this, the cap 28 is 28 may be provided with only the notch 37 in advance, and after the base 28 is fixed to the arrester body 26, the protruding piece 39 may be expanded radially outward 38 using a tool. Further, the protruding piece 39 may be provided on the entire circumferential end surface of the base 28.

Further, in each of the above embodiments, the male screw 32 is
Although the male screw 32 is irremovably engaged with the insertion hole 31 of No. 7, the male screw 32 may be removably inserted into the large diameter insertion hole 31 without providing such a means to prevent it from falling off. In this case, even if the male thread 32 is loosened, the exhaust outlet pipe 19 will not automatically come out of the muffler body 11 together with the male thread 32, but the other end of the exhaust outlet pipe 19 (the right end in FIG. 1) The exhaust outlet pipe 19 can be pulled out by grasping it with a tool such as radio pliers.

[Effects of the invention] As explained above, according to this invention, since the arrester body made of wire mesh is not covered with a frame, the exposed surface area of the wire mesh becomes larger, thereby improving the ability to capture carbon. .

Furthermore, since both ends of the exhaust outlet pipe are attached to the muffler body via the lid and the cap, the exhaust outlet pipe is firmly supported by the muffler body.

Furthermore, since the other end of the exhaust outlet pipe is supported by the muffler body by a protrusion provided on the base, the centering action of the protrusion allows accurate centering between the base and the guide member. Therefore, the gap between the outer periphery of the cap and the inner periphery of the guide member can be kept small, and carbon particles can be prevented from flowing out from this gap.

In addition, when manufacturing the exhaust outlet pipe, after the subassembly of joining the lid to the arrester body is completed, the male screw can be inserted through the arrester body and into the insertion hole of the lid.
The manufacturing process of the exhaust outlet pipe itself is simplified. Furthermore, when joining the lid 27 to the arrester body 26 by brazing or welding, the lid 27 through which the male thread 32 is not inserted is joined to the arrester body 26, so the male thread 32 gets in the way when joining. This makes the joining work easier.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view showing the first embodiment of this invention, Fig. 2 is a longitudinal sectional view showing the exhaust outlet pipe before being incorporated into the muffler shown in Fig. 1, and Fig. 3 is a longitudinal sectional view showing the arrester shown in Fig. 2. 4 is a rear view showing the base of FIG. 2, FIG. 5 is a longitudinal sectional view showing the second embodiment, and FIG. 6 is a longitudinal sectional view showing the third embodiment. , FIG. 7 is a front view of the clip shown in FIG. 6. 10...muffler, 11...muffler body, 19...
...Exhaust outlet pipe, 23...Female thread, 26...Arrester body, 27...Lid, 28...Base, 31...
Insertion hole, 32...Male thread, 33...Engagement groove, 34
...screw seat surface, 36 ... axial direction, 38 ... radially outward, 39 ... projecting piece, 51 ... clip.

Claims (1)

[Claims for Utility Model Registration] (1) An exhaust outlet pipe that is removably attached to the muffler body is arranged inside the muffler body, and this exhaust outlet pipe is connected to the arrester body made of a cylindrical wire mesh, The arrester body includes a lid fixed to one end of the arrester body and a cylindrical cap fixed to the other end of the arrester body. It is attached to the muffler body by screwing a male screw inserted from inside to a female screw provided on the muffler body, and the mouthpiece has a protrusion that expands radially outward. A muffler with a spark arrester attached to the muffler body by abutting the piece against the inner peripheral surface of a cylindrical guide member provided on the muffler body. (2) An engagement groove with a diameter smaller than the outer diameter of the threaded portion is formed at the lower part of the neck of the male screw, and the screw seat surface around the insertion hole of the lid body is formed in a conical shape that protrudes inward in the axial direction. , the screw seating surface is pressed against the muffler body and deformed into a flat plate shape by the screwing of the male and female threads, thereby contracting the inner diameter of the insertion hole and causing the inner peripheral edge to fit into the fitting. A muffler with a spark arrester according to claim 1, which is irremovably engaged in the axial direction with a mating groove. (3) An engagement groove with a smaller diameter than the outer diameter of the threaded portion is formed at the lower part of the neck of the male screw, and the male screw is inserted into the engagement groove of the male screw inserted into the insertion hole of the lid, so that the male screw can be removed from the insertion hole. A muffler with a spark arrester according to claim 1, in which a clip is engaged to prevent a spark arrester from causing a spark arrester.