JPH0763037A - General purpose engine muffler - Google Patents

Abstract

PURPOSE:To provide a general purpose engine muffler that is simple in structure and able to reduce the cost of production sharply and to hold or improve each performance as a muffler. CONSTITUTION:In a muffler to be connected to an exhaust port of an industrial engine via a flange, it is made up of the following procedures that an upper half of the muffler 3 is formed into a sheet metal upper case 4 and the lower half into a cast lower case 5 respectively, while a flanged exhaust pipe part 6 for connecting the cast lower case to the exhaust port of the industrical engine is integrally formed with this lower case with a casting, and both these upper and lower cases are integrally clamped after holding a partition plate 7 in between. In addition, the lower case is made of heat resisting cast steel, and further a rib 10 is formed in space between the lower case 5 and a flange 2 while a muffling corrugated sheet projection is formed on an inner wall of the lower case 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a muffler for a general-purpose engine, which is widely used as a motive power for general industries other than automobiles, for outdoor equipment such as agricultural pumps, cultivators and generators.

[0002]

2. Description of the Related Art In the case of a conventional automobile engine, the exhaust muffler is mounted separately from the body of the engine and separately mounted on the vehicle body. Therefore, there are relatively few restrictions in terms of space and structure and sufficient performance is provided. Although a muffler can be obtained, in the case of a general-purpose engine, the muffler must be integrated with the engine, and the entire engine with the muffler must be compact and compact. As a muffler that is formed correspondingly, the actual muffler 2-13
There is a device described in Japanese Patent No. 1017. The conventional example will be described with reference to FIG. Fig. 4 is the actual Kaihei 2-131017
FIG. 7 is a cross-sectional view of a conventional muffler described in FIG. In the drawing, a muffler chamber 103 communicating with the outflow port 102 is arranged in the muffler body 101 so that a partition 104 of the muffler chamber 103 faces an expansion chamber 106 in the muffler body 101 communicating with the inflow port 105. The partition 104 is generally composed of a single plate.

[0003]

In a general-purpose engine in which the muffler cannot be directly attached to the exhaust port of the engine, (1) an exhaust pipe connecting the exhaust port and the muffler body is required, but it is exposed to high heat and special materials are used. Or it is necessary to perform special processing. (2) It is difficult to secure the welding strength of the connecting flange at the exhaust pipe end. (3) The method of supporting the exhaust pipe and the muffler body needs to be devised, and the welding man-hours are too long for a normal bridge or the like. There are problems such as. SUMMARY OF THE INVENTION It is an object of the present invention to provide a muffler for a general-purpose engine that eliminates the above-mentioned problems, has a simple structure, greatly reduces the production cost, and can sufficiently maintain or improve each performance as a muffler.

[0004]

A first aspect of the present invention is a muffler connected to an exhaust port of a general-purpose engine through a flange, and an upper half of the muffler is a sheet metal upper case 4 and a lower half of the muffler is a cast lower case 5. And a flanged exhaust pipe portion 6 for connecting the cast lower case to an exhaust port of the general-purpose engine is integrally formed with the lower case by casting, and the upper case and the lower case are integrally sandwiched by a partition plate 7. It is characterized by being tightened.

A second aspect of the present invention is the muffler for a general-purpose engine according to the first aspect, characterized in that the lower case 5 is made of heat-resistant cast steel. The third invention is characterized in that the rib 10 is formed between the lower case 5 and the exhaust pipe flange 2 in the general-purpose engine muffler described in the first and second aspects. A fourth invention is characterized in that, in the muffler for a general-purpose engine described in any one of the first to third aspects, a muffling protrusion such as a waveform is formed on the inner wall of the lower case 5.

[0006]

Since the present invention is configured as described above, since the entire muffler lower portion is made of heat-resistant casting, heat treatment for heat resistance including the first expansion chamber is unnecessary, and a thermally stable strength is obtained. It is possible to greatly reduce the production cost of the muffler while keeping it. Moreover, the lower case shape can be made into an arbitrary shape such as a waveform corresponding to the improvement of the silencing characteristic without increasing the production cost. Also, ribs etc. can be added between the lower case and the exhaust pipe part or between the lower case and the flange if necessary without increasing the production cost, which makes it easy to secure the strength and the rigidity of the flange itself, which was difficult with conventional sheet metal. Can be raised.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment according to the present invention will be described with reference to FIGS. 1 is a diagram in which a muffler is attached to a general-purpose engine of the embodiment, FIG. 2 is a front sectional view of the muffler of the embodiment, and FIG. 3 is a partially cutaway view of the muffler of the embodiment. In the figure, 1 is a general-purpose engine, 3 is a muffler, 4 is an upper case, and the upper half of the muffler 3 is made of sheet metal. 5 is a lower case, the lower half of the muffler 3 is a casting (for example, thermal fatigue life; Heat-resistant cast steel, which is excellent in castability and excellent in workability and can be manufactured at low cost, is preferable). Reference numeral 6 denotes an exhaust pipe portion which is formed integrally with the lower case 5 by casting. Two
Is a flange and is provided at the end of the exhaust pipe portion 6 and is a general-purpose engine 1
Connected to the exhaust port of. A partition plate 7 is a porous plate and is sandwiched between the upper case 4 and the lower case 5. Reference numeral 9 is a bolt that is fastened with a partition plate 7 sandwiched between the upper case 4 and the lower case 5. A first expansion chamber 8 is a space inside the lower case 5. Reference numeral 14 denotes an exhaust pipe, the outlet of which is integrally attached to the upper case 4 by welding. A sound deadening material 11 is supported in the exhaust pipe 14. Reference numeral 12 is a pin that is held by the exhaust pipe 14 and supports the sound deadening material 11. Reference numeral 13 denotes an exhaust direction changing plate mounting plate, the upper half of which is fixed to the upper case 4 by welding.

The operation of the first embodiment will be described. The muffler 3 is attached to the general-purpose engine 1 by attaching the flange 2 to the exhaust port. Exhaust gas from the general-purpose engine 1 passes from the exhaust port through the exhaust pipe portion 6, enters the first expansion chamber 8, passes through many holes of the partition plate 7, enters the upper case 4, enters the exhaust pipe 14, and passes through the silencer 11. It is discharged through the outside.
Since the entire lower portion is made of heat-resistant casting, the heat treatment for the first expansion chamber 8 is not required, and the production cost of the muffler 3 is significantly reduced while ensuring the thermally stable strength.

A second embodiment according to the present invention will be described with reference to FIGS. 1 to 3 are the same as those of the first embodiment, the description thereof will be omitted. In the figure, 5 is a lower case made of heat-resistant cast steel. The other reference numerals are the same as those in the first embodiment and will not be described. The operation of the second embodiment is the same as the operation of the first embodiment. A third embodiment according to the present invention will be described with reference to FIGS. 1 to 3 are the same as those of the first embodiment, the description thereof will be omitted. The lower case 5 is made of cast metal or heat-resistant cast steel. A rib 10 is provided between the flange 2, the exhaust pipe portion 6 and the lower case 5. The other reference numerals are the same as those in the first embodiment and will not be described. The operation of the third embodiment will be described. The rib 10 can easily secure the strength without increasing the production cost and can easily increase the rigidity of the flange 2 itself which has been difficult in the past.

A fourth embodiment according to the present invention will be described with reference to FIGS. 1 to 3 are the same as those of the first embodiment, the description thereof will be omitted. The lower case 4 is the same as that of the second embodiment. Reference numeral 10 denotes a rib, which is the same as that in the third embodiment. Reference numeral 5 denotes a lower case, the inner wall shape of which is provided with a muffling protrusion such as a waveform corresponding to improvement of muffling characteristics (not shown) without increasing production cost. The operation of the fourth embodiment will be described. The shape of the inner wall of the lower case 5 improves the sound deadening characteristics. The other actions are the same as the actions of the first to third embodiments, and hence the description thereof is omitted.

[0011]

Since the present invention is constructed as described above, it has the effect of greatly reducing the production cost and maintaining or improving each performance as a muffler.

[Brief description of drawings]

FIG. 1 is a diagram showing how a muffler is attached to a general-purpose engine according to a first embodiment.

FIG. 2 is a front sectional view of the muffler of the first embodiment.

FIG. 3 is a partially cutaway view of the muffler of the first embodiment.

FIG. 4 is a cross-sectional view of a conventional muffler.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... General purpose engine, 2 ... Flange, 3 ... Muffler, 4 ... Upper case, 5 ... Lower case, 6 ... Exhaust pipe part, 7 ... Partition plate, 8 ... 1st expansion chamber.

Claims (4)

[Claims] 1. A muffler connected to an exhaust port of a general-purpose engine through a flange, wherein an upper half of the muffler is a sheet metal upper case (4) and a lower half of the muffler is a cast lower case (5). An exhaust pipe part (6) with a flange (2) for connecting the cast lower case to an exhaust port of the general-purpose engine is integrally formed with the lower case by casting, and the upper case and the lower case are separated by a partition plate (7). A muffler for a general-purpose engine, which is characterized by being clamped together by sandwiching it. 2. The muffler for a general-purpose engine according to claim 1, wherein the lower case (5) is made of heat-resistant cast steel. 3. The general-purpose engine muffler according to claim 1 or 2, wherein a rib (10) is formed between the lower case (5) and the exhaust pipe flange (2). For muffler. 4. The muffler for a general-purpose engine according to any one of claims 1 to 3, wherein a muffling protrusion such as a waveform is formed on the inner wall of the lower case (5).