Muffler of industrial engine

Abstract: A channel (203) of the muffler communicating with an exhaust gas outlet (200b) is integrally formed on the inside of a muffler body (200) made of aluminum diecast and an inner lid (201) is mounted to the open side of the channel (203) to form an exhaust gas passageway (230) serving also as a tail pipe within the muffler main body (200). At the exhaust gas outlet (200b) is formed a projecting wall (204) adapted to butt against the inner lid (201) integrally with the muffler main body (200) so as to prevent the exhaust gas escape without passing through the exhaust gas passageway (230).

Description: BACKGROUND OF THE INVENTION: Field of the Invention: The present invention relates to a muffler of an industrial engine, and more particularly to improvements in a structure of such type of muffler. Description of the Prior Art: As the above-mentioned type of muffler, the inventor of this invention proposed previously in Japanese Utility Model Application No. 63-127369 (1988), a structure of a muffler of an industrial engine, in which a channel communicating with an exhaust gas outlet is formed integrally on the inside of a muffler main body consisting of a diecast article, an inner lid consisting of a diecast or a sheet metal is joined to the open side of the aforementioned channel, and thereby an exhaust gas passageway serving also as a tail pipe is constructed within the muffler main body. Figs. 3 to 5 illustrate the muffler disclosed in the above-referred Japanese Utility Model Application No. 63-127369 (1988), in which on the inside of a muffler main body 100 consisting of an aluminium diecast article having an exhaust gas inlet 100a and an exhaust gas outlet 100b, is formed a U-shaped channel 103 communicating with the exhaust gas outlet 100b by means of a wall 100c constructed integrally with the main body 100, and by joining and fastening, by means of a clamp screw 102, an inner lid 101 consisting of a diecast or a sheet metal on the opening side of the above-mentioned channel 103, an exhaust gas passageway 130 serving also as a tail pipe is constructed within the muffler main body 100, thus as compared to the structure in which a tail pipe is fixed to the exhaust gas outlet 100b of the muffler main body 100, shaping of the tail pipe is facilitated, and also by modifying the shape of the exhaust gas passageway, a path length from the inlet to the outlet can be arbitrarily changed, and tuning with respect to performance (output, noise) is made possible. However, the above-mentioned structure of a muffler in the prior art involved the following problems. That is, in the above-described muffler in the prior art, since the exhaust gas passageway 130 is formed by joining an inner lid 101 consisting of a diecast or a sheet metal to the open side of the channel 103 formed of a diecast, upon fastening this inner lid 101 by means of a clamp screw 102 there is a possibility that the inner lid 101 may be deviated in position by an amount corresponding to a looseness of a through-hole for the clamp screw, and as a result, there was a fear that the exhaust gas may escape directly through a gap formed by the deviation to the exhaust gas outlet 100b without passing through the exhaust gas passageway 130, and so, the muffler cannot achieve the function of a tail pipe. SUMMARY OF THE INVENTION: It is therefore an object of the present invention to provide a muffler of an industrial engine, in which formation of a gap clearance between an open side edge of a channel and an inner lid mounted to the open side of the channel can be prevented. According to the present invention, in a muffler of an industrial engine of the type that a channel communicating with an exhaust gas outlet is integrally formed on the inside of a muffler main body made of an aluminium diecast, and an inner lid is mounted to the open side of the channel to form an exhaust gas passageway serving also as a tail pipe, within the muffler main body, at the exhaust gas outlet is formed a projecting wall adapted to butt against the inner lid, integrally with the muffler main body. Owing to the above-featured construction, according to the present invention, since the inner lid joined to the open side of the channel would butt against the projecting wall on the inside of the exhaust gas outlet and would close the exhaust gas outlet, even if the inner lid to be joined to the open side of the channel should be deviated in position by an amount corresponding to a looseness of a through-hole for a clamp screw, or even if the inner lid should be short due to poor machining precision of parts, a gap clearance would not be formed between the channel and the inner lid, and so it would never occur that exhaust gas escapes directly to the exhaust gas outlet without passing through the exhaust gas passageway. Therefore, the machining precision in size and configuration of parts could be low, hence manufacture of the parts is easily, and the muffler can be easily assembled. The above-mentioned and other objects, features and advantages of the present invention will become more apparent by reference to the following description of preferred embodiments of the invention taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS: In the accompanying drawings: Fig. 1 is a front view showing a preferred embodiment of the present invention; Fig. 2 is a cross-section view taken along line B-B in Fig. 1 as viewed in the direction, of arrows; Fig. 3 is a front view showing a muffler of an industrial engine in the prior art; Fig. 4 is a cross-section view taken along line C-C in Fig. 3 as viewed in the direction of arrows; and Fig. 5 is a cross-section view taken along line D-D in Fig. 3 as viewed in the direction of arrows. DESCRIPTION OF THE PREFERRED EMBODIMENTS: Now, description will be made on a preferred embodiment of the present invention illustrated in Figs. 1 and 2. Referring to these figures, in a muffler main body 200 made of an aluminium diecast are formed an exhaust gas inlet 200a, an exhaust gas outlet 200b and a U-shaped channel 203 communicating with the exhaust gas outlet 200b integrally with the main body 200, to the open side of the channel 203 is secured and fastened an inner lid 201 consisting of a diecast or a sheet metal by means of a clamp screw 203 as butting against walls 200c forming the channel 203, and thus an exhaust gas passageway 230 communicating with the exhaust gas outlet 200b is formed within the muffler main body 200 by means of the channel 203 and the inner lid 201. On the inside of the muffler outlet 200b is provided a projecting wall 204 adapted to butt against the inner lid 201 as projected from the inside of the outlet 200b. As described above, since the projecting wall 204 adapted to butt against the inner lid 201 is formed at the exhaust gas outlet 200b of the exhaust gas passageway 230 formed of the channel 203 within the muffler main body 200 and the inner lid 201 joined to the open side of the channel 203, at the exhaust gas outlet 200b of the exhaust gas passageway 230, the projecting wall 204 projected from the main body and the inner lid 201 are superposed with each other, and so, even if machining precision of the size and configuration of the inner lid 201 should be low, a gap clearance would not be formed therebetween. Accordingly, it would never occur that exhaust gas may directly escape through the exhaust gas outlet 200b without passing through the exhaust gas passageway 230, and also upon fastening the inner lid 201 there is no need to push the inner lid 201 towards the exhaust gas outlet 200b, so that there is an advantage that assembly becomes easy.

Claims: A muffler of an industrial engine, in which a channel (203) communicating with an exhaust gas outlet (200b) is integrally formed on the inside of a muffler main body (200) made of a aluminium diecast, and an inner lid (201) is mounted to the open side of said channel (203) to form an exhaust gas passageway (230) serving also as a tail pipe within the muffler main body (200); characterized in that at said exhaust gas outlet (200b) is formed a projecting wall (204) adapted to butt against said inner lid (201), integrally with said muffler main body (200). A muffler of an industrial engine as claimed in claim 1, in which said projecting wall (204) is formed so as to project on the inside of the muffler main body (200).

Inventors: KATO TOMIYA C O NAGOYA MACHINE, KOBAYASHI YOSHIO C O NAGOYA MA, SATO TORU C O NAGOYA MACHINERY, KATO, TOMIYA C/O NAGOYA MACHINERY WORKS, KOBAYASHI, YOSHIO C/O NAGOYA MACHINERY WORKS, SATO, TORU C/O NAGOYA MACHINERY WORKS
Applicants: MITSUBISHI HEAVY IND LTD, MITSUBISHI JUKOGYO KABUSHIKI KAISHA
Application year: 1990
Main classification: F01N1
IPC codes: F01N7, F01N1