JP3664740B2 - Muffler for general-purpose engine - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a muffler for a general-purpose engine that is widely used for outdoor use equipment such as agricultural pumps, cultivators, and generators as a general industrial driving force except for automobiles.
[0002]
[Prior art]
In the case of conventional automobile engines, the exhaust muffler is attached to the vehicle body separately from the engine body, so there are relatively few restrictions in terms of space and structure, and a muffler with sufficient performance can be obtained. However, in the case of a general-purpose engine, the muffler must be assembled integrally with the engine, and the entire engine assembled with the muffler must be made compact and compact. As a muffler, there is a device described in Japanese Utility Model Laid-Open No. 2-131017. The conventional example will be described with reference to FIG. FIG. 4 is a cross-sectional view of a conventional muffler described in Japanese Utility Model Laid-Open No. 2-131017.
In the figure, the muffler body 101 is arranged in a muffler chamber 103 communicating with the outlet 102 so that the partition wall 104 of the muffler chamber 103 faces the expansion chamber 106 in the muffler main body 101 communicating with the inlet 105. The partition 104 is generally constituted by a single plate.
[0003]
[Problems to be solved by the invention]
For general-purpose engines that cannot directly attach a muffler to the engine exhaust port,
(1) An exhaust pipe connecting the exhaust port and the muffler body is required, but it is necessary to carry out a special material or special treatment because it is exposed to high heat.
(2) It is difficult to ensure the welding strength of the connecting flange at the end of the exhaust pipe.
(3) It is necessary to devise how to support the exhaust pipe and the muffler body, and a normal bridge or the like takes too many welding steps.
There are problems such as.
An object of the present invention is to provide a muffler for a general-purpose engine that eliminates the above-mentioned problems, has a simple structure, greatly reduces production costs, and can sufficiently maintain or improve each performance as a muffler.
[0004]
[Means for Solving the Problems]
The present invention is a muffler disposed above a general-purpose engine and connected to an exhaust port of the engine via a flange. The upper half of the muffler is a sheet metal upper case (4) provided with an exhaust outlet, The lower half of the muffler is a cast lower case (5) , and the upper case and the lower case are integrally tightened with a partition plate (7) formed with a number of holes through which exhaust passes.
An expansion chamber (8) in which the exhaust pipe mounting side is expanded is provided inside the lower case, and is connected to the outer wall on the lower side of the expansion chamber, connected to the exhaust port of the general-purpose engine and curved upward from the exhaust port. The flanged exhaust pipe portion (6) is provided, and the side wall of the exhaust pipe portion (6) closes the space between the curved exhaust pipe portion (6) and the bottom wall of the expansion chamber (8). The expansion chamber (8) is formed with a planar rib extending to the bottom wall, and the lower case including the expansion chamber, the exhaust pipe portion, and the planar rib are integrally formed of a casting, and in particular, the lower case (5) characterized in that the formation of the sound-absorbing projection waveform to the inner wall.
[0006]
[Action]
Since the present invention is configured as described above, the entire muffler lower portion is formed of a heat-resistant casting, so that heat treatment for heat-resistance including the first expansion chamber is unnecessary, while maintaining a thermally stable strength. The production cost of the muffler can be greatly reduced. In addition, the lower case shape can be changed to an arbitrary shape such as a waveform corresponding to the improvement of the silencing characteristics without increasing the production cost. Can be increased easily rigidity of the flange itself was not difficult in this way facilitates securing strength且従come made of sheet metal can additionally installed ribs between the lower case and the exhaust pipe portion or the lower case and the flange without addition increasing the production costs .
[0007]
【Example】
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram in which a muffler is attached to a general-purpose engine of an 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 and the lower half of the muffler 3 is cast (for example, thermal fatigue life; It is preferable to use heat-resistant cast steel that is excellent in castability and has excellent castability and can be manufactured at low cost. Reference numeral 6 denotes an exhaust pipe portion which is formed in the lower case 5 as a single casting. A flange 2 is provided at the end of the exhaust pipe section 6 and is connected to the exhaust port of the general-purpose engine 1.
As shown in FIG. 2, the exhaust pipe section 6 is configured as an exhaust pipe section (6) with a flange (2) connected to the exhaust port and rising upward from the exhaust port.
A partition plate 7 is formed of a porous plate and is sandwiched between the upper case 4 and the lower case 5. A bolt 9 fastens the upper case 4 and the lower case 5 with the partition plate 7 interposed therebetween. Reference numeral 8 denotes a first expansion chamber, which is a space inside the lower case 5. Reference numeral 14 denotes an exhaust pipe whose outlet is integrally attached to the upper case 4 by welding. Reference numeral 11 denotes a sound deadening material supported in the exhaust pipe 14. Reference numeral 12 denotes a pin that is inserted into the exhaust pipe 14 to support the sound deadening material 11. Reference numeral 13 denotes an exhaust direction changing plate mounting plate whose upper half is fixed to the upper case 4 by welding.
[0008]
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 enters the first expansion chamber 8 from the exhaust port through the exhaust pipe portion 6, enters the upper case 4 through many holes of the partition plate 7, enters the exhaust pipe 14, and passes through the silencer 11. It is discharged out through. Since the entire lower part is formed of a heat resistant casting, heat treatment including the first expansion chamber 8 is not required, and the production cost of the muffler 3 is greatly reduced while ensuring a thermally stable strength.
[0009]
A second embodiment according to the present invention will be described with reference to FIGS.
1-3 are omitted from the description of the first embodiment. 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 the description is omitted. The operation of the second embodiment is the same as that of the first embodiment.
A third embodiment according to the present invention will be described with reference to FIGS.
1-3 are omitted from the description of the first embodiment. 5 is a lower case made of cast or heat-resistant cast steel. Reference numeral 10 denotes a rib 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 the description is omitted.
The operation of the third embodiment will be described. The rib 10 can easily increase the rigidity of the flange 2 itself, which is easy to ensure strength and has been difficult in the past without increasing the production cost.
[0010]
A fourth embodiment according to the present invention will be described with reference to FIGS.
1-3 are omitted from the description of the first embodiment. Reference numeral 4 denotes a lower case which is the same as that of the second embodiment. A rib 10 is the same as that in the third embodiment. Reference numeral 5 denotes a lower case, whose inner wall shape has a muffing projection such as a waveform corresponding to improvement of the muffling characteristics (not shown) without increasing the production cost.
The operation of the fourth embodiment will be described.
The shape of the inner wall of the lower case 5 improves the silencing characteristics. Since other operations are the same as those of the first to third embodiments, description thereof will be omitted.
[0011]
【The invention's effect】
Since the present invention is configured as described above, the production cost is greatly reduced, and each performance as a muffler is maintained or improved.
[Brief description of the drawings]
FIG. 1 is a diagram of attaching a muffler 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 (2)

A muffler disposed above a general-purpose engine and connected to an exhaust port of the engine via a flange. The upper half of the muffler is a sheet metal upper case (4) provided with an exhaust outlet. A muffler in which half is a cast lower case (5), and the upper case and the lower case are integrally tightened with a partition plate (7) formed with a number of holes through which exhaust passes.
An expansion chamber (8) in which the exhaust pipe mounting side is expanded is provided inside the lower case, and is connected to the outer wall on the lower side of the expansion chamber, connected to the exhaust port of the general-purpose engine and curved upward from the exhaust port. The flanged exhaust pipe portion (6) is provided, and the side wall of the exhaust pipe portion (6) closes the space between the curved exhaust pipe portion (6) and the bottom wall of the expansion chamber (8). Expansion chamber (8) A muffler for a general-purpose engine, in which a planar rib extending to the bottom wall is formed, and a lower case including the expansion chamber, an exhaust pipe portion, and the planar rib are integrally formed by casting. Muffler for general engine in muffler for a general-purpose engine as set forth in claim 1, wherein, characterized in that the formation of the sound-absorbing projection waveform to the inner wall of the lower case (5).

Images