JP6447110B2 - Exhaust pipe muffler and manufacturing method thereof - Google Patents

Description

  The present invention relates to an automobile exhaust pipe muffler and a method for manufacturing the same.

  The use of automobiles is increasing year by year from the viewpoint of convenience as a means of transportation. As the use of automobiles increases, air pollution caused by exhaust gas, noise pollution caused by automobile engines, and recyclability of automobiles become major problems. The noise pollution of automobiles can be broadly divided into engine noise and engine exhaust noise. Engine noise can be reduced by surrounding the engine with a casing. Regarding noise, noise can be reduced by installing a muffler (silencer) in the exhaust passage.

  Exhaust gas discharged from the automobile engine is sent from the exhaust manifold to the catalytic converter, where harmful components in the exhaust gas are removed by oxidation and reduction reactions, and then passed to the sub-muffler through the upstream exhaust pipe (front pipe). In this sub-muffler, the sound of various frequencies contained in the exhaust flow from the engine, the unpleasant and unpleasant high-frequency sound is removed, and the exhaust flow from which the unpleasant high-frequency sound is removed is removed from the exhaust pipe on the downstream side. Is sent to a main muffler that removes low-frequency sound contained in the exhaust flow, and then discharged to the atmosphere from an exhaust pipe (tail pipe) connected to the main muffler.

  As a main muffler installed in the exhaust passage, mineral fibers such as glass wool, basaltic wool or rock wool, carbon fiber, etc., between steel sheets wound in a double manner to remove low-frequency sound contained in the exhaust flow A muffler (silencer) in which a sound absorbing material or a sound insulating material is interposed has been proposed (Patent Document 1, Patent Document 2, and Patent Document 3).

Japanese Utility Model Publication No. 58-15618 JP-A-10-306721 Japanese Patent Laid-Open No. 11-324637

  With the increase in the output and speed of automobile engines, the speed of the exhaust flow flowing into the muffler has increased. Therefore, in the exhaust passage where the speed and pressure fluctuate rapidly, it is used as a sound absorbing material or sound insulation material in the muffler. There is a possibility that the glass wool or the like that is deteriorated or scattered due to use over time, resulting in a problem that the noise reduction (sound absorption) effect at the time of design cannot be obtained.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a muffler for an automobile exhaust pipe including a sound absorbing material capable of maintaining a silencing effect during design over a long period of time, and a method for manufacturing the muffler. It is in.

  A muffler for an automobile exhaust pipe according to the present invention includes a cylindrical inner shell, a cylindrical outer shell surrounding the outer peripheral surface of the inner shell, a sound absorbing material disposed between the inner shell and the outer shell, and containing expanded graphite. A cylindrical shell body, an input-side outer plate that closes one opening of the shell body, an output-side outer plate that closes the other opening of the shell body, and an input-side outer plate And an outlet pipe penetrating the outer plate on the output side.

  According to the exhaust pipe muffler of the present invention, since it includes expanded graphite having heat resistance and vibration damping action, the low frequency radiated in addition to the propagated vibration even in a high temperature region exceeding 600 ° C. In addition, it is possible to reduce the radiated sound of the sound absorbing material, and to reduce the deterioration of the sound absorbing material and the scattering of the sound absorbing material when used for a long period of time at a high temperature.

  The exhaust pipe muffler according to the present invention may be used for a two-wheeled vehicle, a four-wheeled vehicle, a sub-muffler, and a main muffler.

  In the automobile exhaust pipe muffler according to the present invention, a shell assembly for supporting the inlet pipe and the outlet pipe and partitioning the inside of the shell body into a plurality of chambers may be accommodated in the shell body.

  In the automobile exhaust pipe muffler in which the intermediate assembly is accommodated in the shell body, the sound absorption effect can be further enhanced because the interior of the shell body is partitioned into a plurality of chambers.

  In the muffler for an automobile exhaust pipe of the present invention, the sound absorbing material may contain phosphate or phosphate and phosphoric acid in addition to expanded graphite.

  If the sound-absorbing material contains phosphate or phosphate and phosphoric acid and expanded graphite, the heat-resistance of the sound-absorbing material is further improved, so that the sound-absorbing effect in the high-temperature region can be further exhibited and used for a long time at a high temperature. As a result of further reducing deterioration and scattering in the case, the sound absorption effect at the time of design can be maintained for a longer period of time.

  In the exhaust pipe muffler of the present invention, the shell body includes an inner shell having a circular cross section or an elliptical cross section and an outer shell having a circular cross section or an elliptical cross section surrounding the outer peripheral surface of the inner shell. In addition, it is formed by winding a single metal plate into a cylindrical shape or an elliptical cylinder, and joining the overlapping portions formed by overlapping the circumferential ends in the circumferential direction. An inner shell and an outer shell having a circular cross section or an elliptical cross section may be provided.

  As the metal material forming the inner shell and the outer shell, a hot-dip aluminum-plated steel plate or a stainless steel plate is preferably used. And austenitic stainless steel such as SUSXM15J1. The thickness of the inner shell and the outer shell is preferably 0.3 mm or more, and more preferably 0.7 mm to 1 mm. Furthermore, a punching metal or a metal mesh may be used for the metal material forming the inner shell and the outer shell instead of the non-porous plate.

  In the exhaust pipe muffler of the present invention, the sound absorbing material interposed between the inner shell and the outer shell extends over the entire circumference of the outer peripheral surface and the inner peripheral surface between the outer peripheral surface of the inner shell and the inner peripheral surface of the outer shell. It may be interposed, or may be interposed only in a gap between the outer peripheral surface of the inner shell and the inner peripheral surface of the outer shell facing each other in a direction orthogonal to the axial direction of the shell body.

  In the exhaust pipe muffler of the present invention, the shell body may include an inner shell having an elliptical cross section and an outer shell having an elliptical cross section surrounding the outer peripheral surface of the inner shell, or a single metal An inner shell and an outer shell having an elliptical cross-section formed by joining a superposed portion obtained by winding a plate material made in an elliptical shape in a cross-sectional shape and overlapping the circumferential end portions in the circumferential direction. You may do it.

  In the exhaust pipe muffler of the present invention, the sound absorbing material interposed between the inner shell and the outer shell having an elliptical cross section is formed between the outer peripheral surface and the inner peripheral surface of the inner shell. It may be interposed over the entire circumference in the circumferential direction, or may be interposed only in gaps facing each other in the minor axis direction between the outer peripheral surface of the inner shell and the inner peripheral surface of the outer shell.

  The above-described method for manufacturing a muffler for an automobile exhaust pipe according to the present invention includes a plate body serving as a cylindrical inner shell, a plate body serving as a cylindrical outer shell, an outer peripheral surface of the plate body serving as the inner shell, and the outer shell. Forming a cylindrical shell body having an expanded graphite sheet as a sound absorbing material interposed between the inner peripheral surface of the plate body to be wound around the plate body to be the inner shell and input The outer pipe on the side is fixed to one end surface of the shell body so that the inlet pipe provided in the shell body penetrates the outer plate on the input side, and one side of the shell body is secured by the outer plate on the input side. The output side outer plate on the other end surface of the shell body, and the outlet pipe provided in the shell body penetrates the output side outer plate. In the so that, by fixing consists of closing the other opening of the shell body by the output side of the outer plate.

  According to the present invention, the sound-absorbing material containing expanded graphite interposed between the inner shell and the outer shell of the shell body has heat resistance and vibration damping action, so that it only reduces the transmitted vibration. In addition, it is possible to reduce radiated low-frequency radiated sound, and with such a sound-absorbing material, deterioration and scattering during long-term use at high temperatures are reduced, resulting in a long-term sound-absorbing effect during design. A muffler for an automobile exhaust pipe that can be maintained over a wide range and a method for manufacturing the same.

FIG. 1 is an explanatory plan view of an example of a preferred embodiment of the present invention. FIG. 2 is a cross-sectional explanatory view of FIG. FIG. 3 is a cross-sectional explanatory view of the shell body in the example of FIG. FIG. 4 is a cross-sectional explanatory view of the manufacturing process of the example of FIG. FIG. 5 is a cross-sectional explanatory view taken along the line VV shown in FIG. FIG. 6 is a cross-sectional explanatory view taken along the line VI-VI in FIG. FIG. 7 is a perspective explanatory view of a plate material. FIG. 8 is a cross-sectional explanatory view of the manufacturing method of the example of FIG. FIG. 9 is a perspective explanatory view of a composite plate of a plate material and a sound absorbing material. FIG. 10 is a cross-sectional explanatory view of the manufacturing method of the example of FIG. FIG. 11 is a cross-sectional explanatory diagram of the manufacturing method of the example of FIG. 12 is a cross-sectional explanatory view of another manufacturing method of the example shown in FIG. FIG. 13 is a cross-sectional explanatory view of another shell body in the example of FIG. FIG. 14 is a perspective explanatory view of the composite plate material in the example of FIG. FIG. 15 is an explanatory plan view of an example of another preferred embodiment of the present invention. FIG. 16 is a cross-sectional explanatory view of the shell body in the example of FIG. FIG. 17 is a perspective explanatory view of the composite plate material in the example of FIG. 18 is a cross-sectional explanatory view of still another shell body in the example of FIG. FIG. 19 is a cross-sectional explanatory view of the middle assembly in the example of FIG. 20 is a cross-sectional explanatory view taken along the line XX-XX shown in FIG. 21 is a cross-sectional explanatory view taken along the line XXI-XXI shown in FIG. FIG. 22 is a cross-sectional explanatory view of still another shell body. FIG. 23 is a cross-sectional explanatory view of still another shell body.

  Next, the present invention will be described in detail based on an example of a preferred embodiment shown in the drawings. The present invention is not limited to these examples.

  1 to 3, an automobile exhaust pipe muffler 1 of this example includes a cylindrical inner shell 2 having a circular cross section, and a cylindrical outer shell 3 that surrounds the outer peripheral surface of the inner shell 2 and has a circular cross section. A cylindrical shell main body 5 provided between the outer peripheral surface of the inner shell 2 and the inner peripheral surface of the outer shell 3 and including a sound absorbing material 4 containing expanded graphite; The assembly assembly 6, an input-side outer plate 8 that closes one opening 7 of the shell body 5, an output-side outer plate 10 that closes the other opening 9 of the shell body 5, and the outer plate 8 pass through. And an outlet pipe 12 penetrating the outer plate 10.

  The intermediate assembly 6 accommodated in the shell body 5 and supporting the inlet pipe 11 and the outlet pipe 12 includes a circular plate portion 13, a cylindrical protruding portion 14 provided to protrude from the outer peripheral edge of the circular plate portion 13, Cylindrical protrusions projecting from the circular plate part 13 in the opposite direction to the cylindrical projecting part 14 with holes 15 and 16 formed by burring at intervals in the radial direction Y on the circular plate part 13 and an inner peripheral surface defining the hole 15 Each of which has a cylindrical portion 18 projecting from the circular plate portion 13 in the same direction as the cylindrical projecting portion 14 with an inner peripheral surface defining the portion 17 and the hole 16, and axially extending the cylindrical projecting portion 14 in opposite directions. X includes two inner plates 19 arranged at a predetermined interval, and the inlet pipe 11 passes through the respective holes 15 of the inner plate 19. Are supported on the cylindrical projecting portion 17 of each of the inner plate 19 as well as, the outlet pipe 12 is supported in the cylindrical portion 18 of each of the inner plates 19 with through holes 16 of each of the inner plates 19.

  The inlet pipe 11 and the outlet pipe 12 are fixed to the cylindrical projecting portion 17 and the cylindrical portion 18 by welding means such as spot welding or press-fitting means such as fitting, and one end of each of the inlet pipe 11 and the outlet pipe 12. The portion is disposed so as to protrude outside the shell body 5 in the axial direction X through the openings 7 and 9 of the shell body 5.

  Each of the outer plates 8 and 10 closing the openings 7 and 9 at both ends of the shell body 5 includes a main body portion 21 having a bulging portion 20 bulging outward and an outer peripheral edge of the circular opening portion 22 of the main body portion 21. An annular flange 23 formed on the outer circumferential edge of the annular flange 23, a cylindrical protrusion 24 protruding in the opposite direction to the bulging portion 20 in the axial direction X from the outer peripheral edge of the annular flange 23, and a through hole 25 formed in the main body 21. The outer plate 8 has a cylindrical inner peripheral surface 26 and a cylindrical projecting portion 27 projecting in the axial direction X from the main body portion 21, and the outer plate 8 brings the annular flange 23 into contact with one end surface 28 of the shell main body 5. The cylindrical protruding portion 24 is fitted to the outer peripheral surface of one end portion of the shell main body 5, and the end portion of the inlet pipe 11 protruding from the opening portion 7 of the shell main body 5 is fixed to the cylindrical inner peripheral surface 26 of the cylindrical protruding portion 27. Let shell The outer plate 10 closes the opening 7 of the body 5, the outer plate 10 brings the annular flange 23 into contact with the other end surface 29 of the shell body 5, and the cylindrical protrusion 24 is the outer peripheral surface of the other end of the shell body 5. The end portion of the outlet pipe 12 protruding from the opening 9 of the shell body 5 is fixed to the cylindrical inner peripheral surface 26 of the cylindrical protrusion 27 to close the opening 9 of the shell body 5.

    The sound absorbing material 4 containing expanded graphite may be formed as follows.

<Sound Absorbing Material 4: Part 1>
While stirring concentrated sulfuric acid having a concentration of 98%, a 60% aqueous solution of hydrogen peroxide as an oxidant is added to make a reaction solution. The reaction solution is cooled and maintained at a temperature of 10 ° C., and flaky natural graphite powder having a particle size of 30 to 80 mesh is added thereto and reacted for 30 minutes. After the reaction, the acid-treated graphite powder subjected to suction filtration is separated, and the washing operation of stirring the acid-treated graphite powder with water for 10 minutes and suction filtration is repeated twice to sufficiently remove the sulfuric acid content from the acid-treated graphite powder. Next, the acid-treated graphite powder from which sulfuric acid has been sufficiently removed is dried in a drying furnace maintained at a temperature of 110 ° C. for 3 hours to obtain an acid-treated graphite powder.

  The acid-treated graphite powder is heated (expanded) at a temperature of 950 to 1200 ° C. for 1 to 10 seconds to generate a decomposition gas from the acid-treated graphite powder, and the graphite layer is expanded and expanded by the gas pressure. Graphite particles (expansion magnification of 240 to 300 times) are formed. The expanded graphite particles may be supplied to a double-roller apparatus adjusted to a desired roll gap and roll-molded to produce an expanded graphite sheet having a desired thickness, and the expanded graphite sheet may be used as the sound absorbing material 4.

<Sound Absorbing Material 4: Part 2 and Part 3>
While stirring the acid-treated graphite powder, a solution obtained by diluting a 50% concentration of an aluminum phosphate aqueous solution or a first aluminum phosphate aqueous solution as a phosphate salt and a 84% orthophosphoric acid aqueous solution as a phosphoric acid with methanol into the acid-treated graphite powder. Blend in a spray and stir uniformly to make a wettable mixture. The wettable mixture is dried for 2 hours in a drying oven maintained at a temperature of 120 ° C. Subsequently, this was heated (expanded) at a temperature of 950 to 1200 ° C. for 1 to 10 seconds to generate decomposition gas, and expanded graphite particles (expansion magnification: 240 to 300) expanded by expanding the graphite layer by the gas pressure. Times). In this expansion treatment step, orthophosphoric acid in the component undergoes a dehydration reaction to produce phosphorus pentoxide, and water in the structural formula is eliminated from the primary aluminum phosphate. The expanded graphite particles are supplied to a twin-roller device adjusted to a desired roll gap and roll-molded to produce an expanded graphite sheet having a desired thickness. In the thus-produced expanded graphite sheet, a phosphate is added. The contained expanded graphite sheet may be used as the sound absorbing material 4, and the expanded graphite sheet containing phosphoric acid and phosphate may be used as the sound absorbing material 4. The expanded graphite containing phosphate or phosphate and phosphoric acid has excellent heat resistance. Therefore, even when used in a high temperature region, for example, from 600 ° C. to over 600 ° C., deterioration such as oxidation consumption does not occur, and a sound absorbing effect can be obtained over a long period of time. Examples of the phosphate contained in the expanded graphite include primary lithium phosphate, secondary lithium phosphate, primary calcium phosphate, secondary calcium phosphate and secondary aluminum phosphate in addition to primary aluminum phosphate. Examples of phosphoric acid contained in the expanded graphite include metaphosphoric acid, polyphosphoric acid, polymetaphosphoric acid and the like in addition to orthophosphoric acid.

As the sound absorbing material 4, an expanded graphite sheet having a density of about 1.0 to 1.15 Mg / m ³ and a thickness of about 0.3 to 0.6 mm is preferable.

  Next, a method for manufacturing the above-described automobile exhaust pipe muffler 1 will be described.

  As shown in FIGS. 4 to 6, two circular inner plates 19, an inlet pipe 11 and an outlet pipe 12 are prepared, and the respective cylindrical protrusions 14 of the inner plate 19 are directed in the axial direction X in opposite directions. At the same time, they are arranged in the axial direction X at a predetermined interval. The inlet pipe 11 is passed through the hole 15 of the inner plate 19, the inlet pipe 11 is supported by the cylindrical protrusion 17, the outlet pipe 12 is passed through the hole 16 of the inner plate 19, and the outlet pipe 12 is supported by the cylindrical part 18. Then, the inlet pipe 11 and the outlet pipe 12 are fixed to the cylindrical projecting portion 17 and the cylindrical portion 18 by spot welding, and the intermediate assembly 6 is manufactured.

  Next, as shown in FIG. 7, the length of the outer peripheral surface of the cylindrical projecting portion 14 of the inner plate 19 of the intermediate assembly 6 is made of a metal such as a hot-dip aluminum-plated steel plate or a stainless steel plate, and surrounds the entire circumference in the circumferential direction. A single plate member 30 having a length 1 corresponding to the above and a width w exceeding the interval in the axial direction X of the inner plate 19 is prepared.

  As shown in FIG. 8, a single plate member 30 is wound around the outer peripheral surface of the cylindrical protrusion 14 of the inner plate 19, the contact portion between the plate member 30 and the outer peripheral surface of the cylindrical protrusion 14, and the butt end portion of the plate member 30. 31 is fixed integrally by spot welding, and the cylindrical plate body 32 which exhibits the circular cross-section used as the inner shell 2 on the outer peripheral surface of the cylindrical protrusion part 14 of the inner plate 19 is formed.

  Next, as shown in FIG. 9, a plate material 33 similar to the plate material 30, and any one of the sound absorbing materials 4 described in <Sound absorbing material 4: Part 1> and <Sound absorbing material 4: Part 2 and Part 3>. An expanded graphite sheet 34 is prepared. A plate material 33 in which an expanded graphite sheet 34 having a length corresponding to the length surrounding the outer peripheral surface of the cylindrical plate 32 is formed to a length corresponding to the length surrounding the outer peripheral surface of the cylindrical plate 32 and the expanded graphite sheet 34. The composite board | plate material 36 affixed on the one surface 35 of this is formed.

  The composite plate material 36 is wound around the outer peripheral surface of the cylindrical plate body 32 with the expanded graphite sheet 34 of the composite plate material 36 inside, and the butt end portion 37 of the plate material 33 of the composite plate material 36 is fixed by spot welding, as shown in FIG. As shown, a shell body 5 having a cylindrical plate body 32 and a cylindrical plate body 38 having a circular cross section that forms an outer shell 3 wound around an outer peripheral surface of the cylindrical plate body 32 via an expanded graphite sheet 34. A composite cylindrical body 39 is produced.

  Thus, the inner shell 2 having a circular cross section, the outer shell 3 having a circular cross section wound around the outer peripheral surface of the inner shell 2, the outer peripheral surface of the inner shell 2, and the outer shell 3 A shell body 5 provided with a sound absorbing material 4 containing expanded graphite interposed over almost the entire inner peripheral surface is integrally formed on the outer peripheral surface of each cylindrical protrusion 14 of the inner plate 19.

  As shown in FIG. 11, the outer plates 8 and 10 are prepared, the annular flange 23 of the outer plate 8 is brought into contact with one end surface 28 of the shell body 5, and the outer peripheral surface of one end portion of the shell body 5 is placed on the outer peripheral surface. The cylindrical projecting portion 24 of the plate 8 is fitted, the cylindrical inner peripheral surface 26 defining the through hole 25 of the outer plate 8 is passed through the inlet pipe 11, and the outer peripheral surface of the end portion of the shell body 5 and the cylindrical projection of the outer plate 8. The part 24 is fixed and integrated by welding means, and the outer plate 8 closes the one opening 7 of the shell body 5. Similarly, the annular flange 23 of the outer plate 10 is formed on the other end surface 29 of the shell body 5. The cylindrical projection 24 of the outer plate 10 is fitted to the outer peripheral surface of the other end of the shell body 5 so that the through hole 25 of the outer plate 10 is regulated. The outer peripheral surface of the shell main body 5 and the cylindrical protrusion 24 of the outer plate 10 are fixedly integrated by welding means, and the other end of the shell main body 5 is fixed by the outer plate 10. By closing the opening 9, the exhaust pipe muffler 1 shown in FIGS. 1 and 2 is manufactured, the interior of which is divided into three chambers 1 a, 1 b, 1 c by inner plates 19 and 19.

  In the exhaust pipe muffler 1, the inlet pipe 11 is connected to the exhaust pipe upstream of the exhaust gas, and the outlet pipe 12 is connected to the exhaust pipe downstream of the exhaust gas. The vibration propagated from the engine into the exhaust pipe muffler 1 is reduced by the expanded graphite of the sound absorbing material 4 interposed between the outer peripheral surface of the inner shell 2 of the shell body 5 and the inner peripheral surface of the outer shell 3. In addition, since the low-frequency radiated sound radiated from the automobile exhaust pipe muffler 1 is also reduced by the expanded graphite of the sound absorbing material 4, the sound absorption effect set during the design of the automobile exhaust pipe muffler can be maintained for a long period of time.

  Examples of the welding means for integrating the outer peripheral surface of the end portion of the shell body 5 and the cylindrical protrusion 24 of the outer plates 8 and 10 include plasma welding, TIG welding, and laser welding.

  Next, another manufacturing method for the exhaust pipe muffler 1 of this example will be described.

  A plate material 30 similar to the metal plate material 30 prepared in the step shown in FIG. 7 is prepared, and the plate material 30 is wound around the outer peripheral surface of the cylindrical core P as shown in FIG. The circumferential end portion 31 is welded to produce a cylindrical plate 32. Next, a composite plate material 36 similar to the composite plate material 36 prepared in the step shown in FIG. 9 is prepared, and the composite plate material 36 is wound around the outer peripheral surface of the cylindrical plate body 32 with the expanded graphite sheet 34 of the composite plate material 36 inside. A cylindrical plate made of a plate member 33 fixed by spot welding at a circumferential end portion 37 of the plate member 33 and wound around the outer peripheral surface of the cylindrical plate member 32 and the cylindrical plate member 32 via an expanded graphite sheet 34. A composite cylindrical body 39 including the body 38 is produced. The produced composite cylindrical body 39 was removed from the core P, and as shown in FIG. 3, the cylindrical plate body 32 having a circular cross section serving as the inner shell 2 and the outer peripheral surface of the cylindrical plate body 32 were disposed. A cylindrical plate body 38 having a circular cross-section serving as the outer shell 3 and an expanded graphite sheet 34 serving as a sound absorbing material 4 interposed between the outer peripheral surface of the cylindrical plate body 32 and the inner peripheral surface of the cylindrical plate body 38 are provided. A composite cylindrical body 39 to be the shell body 5 is prepared in advance.

  After the intermediate assembly 6 produced in the process shown in FIG. 4 is press-fitted into the shell body 5, the same as the process shown in FIG. 11, the same as the muffler 1 for an automobile exhaust pipe shown in FIGS. An automobile exhaust pipe muffler 1 is manufactured.

  Also in the automobile exhaust pipe muffler 1 manufactured in this way, the vibration propagated inside the automobile exhaust pipe muffler 1 is interposed between the outer peripheral surface of the inner shell 2 of the shell body 5 and the inner peripheral surface of the outer shell 3. Since the low-frequency radiated sound radiated from the muffler 1 for an automobile exhaust pipe is reduced by the expanded graphite of the sound absorbing material 4 and the expanded graphite of the sound absorbing material 4 is also reduced, the sound absorption effect set when designing the muffler for the automobile exhaust pipe Can be maintained over a long period of time.

  As shown in FIG. 13, the shell main body 5 in the automobile exhaust pipe muffler 1 includes an inner shell 2 having a circular cross section and an outer shell 3 having a circular cross section disposed around the outer peripheral surface of the inner shell 2. In addition, it includes two expanded graphites that are opposed to each other in the direction orthogonal to the axial direction X between the outer peripheral surface of the inner shell 2 and the inner peripheral surface of the outer shell 3, in other words, arranged in the circumferential direction. The sound absorbing material 4 may be provided.

  As shown in FIG. 13, the shell body 5 may include a sound absorbing material 4 composed of two expanded graphite sheets 34 facing each other in a direction orthogonal to the axial direction X, as shown in FIG. 13. The shell body 5 is provided with a plate material 33 similar to the metal plate material 33 prepared in the step shown in FIG. 9 and two expanded graphite sheets 34, and as shown in FIG. 14, one surface 35 of the plate material 33. A composite plate material 40 is prepared by attaching two expanded graphite sheets 34 to the plate material 33 at a predetermined interval in the longitudinal direction of the plate material 33, and the composite plate material is formed on the outer peripheral surface of the cylindrical plate 32 formed in advance in the process shown in FIG. 40 is wound with the expanded graphite sheet 34 on the inside and the two expanded graphite sheets 34 are arranged so as to face each other in a direction orthogonal to the axial direction X, and the butt end 37 of the plate 33 of the composite plate 40 is wound. Spot welded with the inner shell 2 And a cylindrical plate 38 having a circular cross section that forms the outer shell 3 wound around the outer peripheral surface of the cylindrical plate 32 as the sound absorbing material 4 via the expanded graphite sheet 34. A cylindrical body 39 can be produced and formed with such a composite cylindrical body 39, and the muffler 1 for an automobile exhaust pipe can be formed in the same manner as the process shown in FIG. 11 by using the shell body 5 shown in FIG. May be produced.

  A sound-absorbing material 4 containing expanded graphite composed of two expanded graphite sheets 34 disposed opposite to each other in a direction orthogonal to the axial direction X between the outer peripheral surface of the inner shell 2 and the inner peripheral surface of the outer shell 3. The muffler 1 for an automobile exhaust pipe provided with the provided shell body 5 has the same effect as described above.

  The automobile exhaust pipe muffler 1 shown in FIGS. 15 to 17 may include the shell main body 5 shown in FIG. 15, and the shell main body 5 shown in FIG. The inner shell 2 is formed by a cylindrical winding of the inner shell 2 and located at the innermost periphery, and the outermost outer periphery is formed by a second cylindrical winding of the plate member 41 surrounding the outer peripheral surface of the inner shell 2. And the sound absorbing material 4 including expanded graphite interposed between the outer peripheral surface of the inner shell 2 and the inner peripheral surface of the outer shell 3 over substantially the entire outer peripheral surface and inner peripheral surface. The shell body 5 shown in FIGS. 15 and 16 has a long metal plate 41 and one end surface 42 of the plate 41 along the longitudinal direction of the plate 41 as shown in FIG. From the affixed expanded graphite sheet 34 4 is wound around the outer peripheral surface of the cylindrical projecting portion 14 of the inner plate 19 in the step shown in FIG. 4 with the expanded graphite sheet 34 outside, and the plate member 41 is positioned on the innermost periphery. 41 is further wound once so as to surround the surface of the expanded graphite sheet 34 to position the plate material 41 on the outermost periphery, and the outer peripheral surface of the plate material 41 positioned on the innermost periphery and the plate material 41 positioned on the outermost periphery. As shown in FIG. 16, the expanded graphite sheet 34 is disposed between the inner peripheral surface and the end surface 44 of the innermost peripheral plate member 41 and the outermost peripheral plate member 41, as shown in FIG. It can be formed by integrating by spot welding 47 at the overlap margin 46 of the end portion 45 of the plate material 41.

  Furthermore, as shown in FIG. 18, the shell body 5 includes an inner shell 2 having an elliptical cross section, an outer shell 3 having an elliptical cross section disposed around the outer peripheral surface of the inner shell 2, and an inner shell 2. A sound absorbing material 4 including expanded graphite interposed between the outer peripheral surface of the shell 2 and the inner peripheral surface of the outer shell 3 may be provided.

  In the automobile exhaust pipe muffler 1 provided with the elliptical cylindrical shell body 5 shown in FIG. 18, the middle assembly 6 has an elliptical plate portion 49 and an outer portion of the elliptical plate portion 49 as shown in FIGS. An elliptical annular projecting portion 48 provided projecting from the periphery, holes 50 and 51 formed by burring in the elliptical plate portion 49 at intervals in the radial direction Y, and an inner peripheral surface defining the hole 50 is elliptical. A cylindrical projecting portion 52 projecting in the opposite direction from the annular projecting portion 48 from the shape plate portion 49 and a cylindrical projecting portion 53 projecting in the same direction as the annular projecting portion 48 from the elliptical plate portion 49 with an inner peripheral surface defining the hole 51 are provided. The inner assembly 54 includes two inner plates 54 each having an annular projecting portion 48 facing away from each other and arranged at a predetermined interval in the axial direction X. And The inlet pipe 11 passes through each hole 50 of the inner plate 54 and is fixed to each cylindrical protrusion 52 of the inner plate 54 by spot welding, and is supported by the cylindrical protrusion 52. The outlet pipe 12 is The inner plate 54 passes through the respective holes 51 and is fixed to the respective cylindrical protrusions 53 of the inner plate 54 by spot welding and supported by the cylindrical protrusions 53.

  19 to FIG. 21, the inner shell 2 joined at the butt end 55 by spot welding and the butt end 56 by spot welding surrounding the outer peripheral surface of the inner shell 2. The outer shell 3 joined in the above, the sound absorbing material 4 containing expanded graphite interposed between the outer peripheral surface of the inner shell 2 and the inner peripheral surface of the outer shell 3, and the shell main body 5 shown in FIG. The outer plates 8 and 10 that are integrally formed on the outer peripheral surface of each annular protrusion 48 of the inner plate 54 and close the openings 7 and 9 at both ends in the axial direction X of the shell body 5 are It has an oval body portion 21 with a bulging portion 20 bulging outward.

  Further, as shown in FIG. 22, the automobile exhaust pipe muffler 1 has an elliptical cross section in which the plate material 41 is integrated by spot welding 63 at the overlap allowance 62 in the same manner as the shell body 5 shown in FIG. An inner shell 2 having a surface ellipse shape, an outer shell 3 having an elliptical cross section disposed around the outer peripheral surface of the inner shell 2, and an outer peripheral surface of the inner shell 2 and an inner peripheral surface of the outer shell 3. A shell main body 5 having a sound absorbing material 4 containing intercalated expanded graphite may be provided. Furthermore, as shown in FIG. 23, an inner shell 2 having an elliptical cross section, Two outer shells 3 having an elliptical cross section arranged around the outer peripheral surface and two outer shells that are opposed to each other in the minor axis direction between the outer peripheral surface of the inner shell 2 and the inner peripheral surface of the outer shell 3 The shell main body 5 having the sound absorbing material 4 containing expanded graphite may be provided. The shell main body 5 having an elliptical cross section has an inner shell 2 opposed to at least the minor axis direction having low rigidity. Since the sound absorbing material 4 containing expanded graphite is disposed between the outer shell 3 and the outer shell 3, the sound emitted from the sound absorbing material 4 can be effectively silenced.

  In the above example, the sound absorbing material similar to the sound absorbing material 4 is applied to at least one of the outer plates 8 and 10, the inner plates 19 and 54, the inlet pipe 11 and the outlet pipe 12 to further improve the noise reduction effect. You may do it.

DESCRIPTION OF SYMBOLS 1 Automobile exhaust pipe muffler 2 Inner shell 3 Outer shell 4 Sound absorbing material 5 Shell body 6 Middle assembly 8, 10 Outer plate 11 Inlet pipe 12 Outlet pipe 19, 54 Inner plate

Claims (8)

A cylindrical shell body comprising a cylindrical inner shell, a cylindrical outer shell surrounding the outer peripheral surface of the inner shell, and a sound absorbing material disposed between the inner shell and the outer shell and containing expanded graphite and phosphate An input-side outer plate that closes one opening of the shell body, an output-side outer plate that closes the other opening of the shell body, an inlet pipe that passes through the input-side outer plate, and an output And an outlet pipe penetrating the outer plate on the side, and the sound absorbing material is a muffler for an automobile exhaust pipe containing phosphoric acid in addition to expanded graphite and phosphate .   The muffler for an automobile exhaust pipe according to claim 1, wherein a middle assembly that supports the inlet pipe and the outlet pipe and partitions the inside of the shell body into a plurality of chambers is accommodated in the shell body. The automobile exhaust pipe muffler according to claim 1, wherein the inner shell and the outer shell are circular in cross section or elliptical in cross section. The inner shell and the outer shell are each formed of a single plate material formed by joining a superposed portion in which circumferential ends are overlapped in the circumferential direction while being wound twice. The muffler for automobile exhaust pipes according to one item. The automobile exhaust pipe muffler according to any one of claims 1 to 4, wherein the sound absorbing material is interposed between the outer peripheral surface of the inner shell and the inner peripheral surface of the outer shell over the entire circumference of the outer peripheral surface and the inner peripheral surface. . 5. The sound absorbing material is interposed only in a gap between the outer peripheral surface of the inner shell and the inner peripheral surface of the outer shell that is opposed to each other in a direction orthogonal to the axial direction of the shell body. Auto exhaust pipe muffler. The inner shell and the outer shell have an elliptical cross section, and the sound absorbing material is interposed only in a gap facing each other in the minor axis direction between the outer peripheral surface of the inner shell and the inner peripheral surface of the outer shell. The muffler for automobile exhaust pipes according to any one of 1 to 4. A plate body serving as a cylindrical inner shell, a plate body serving as a cylindrical outer shell, and an outer peripheral surface of the plate body serving as the inner shell and an inner peripheral surface of the plate body serving as the outer shell. A cylindrical shell body having an expanded graphite sheet as a sound absorbing material wound around a plate body serving as an inner shell, and an outer plate on the input side is formed on one end surface of the shell body. The inlet pipe provided in the main body is fixed so as to penetrate the input outer plate, and one opening of the shell body is closed by the input outer plate, and the output outer plate is shelled. The outlet pipe provided in the shell main body is fixed to the other end surface of the main body so as to pass through the outer plate on the output side, and the outer plate on the output side is fixed. How by closing the other opening of the shell body, to produce a muffler for an automobile exhaust pipe according to claim 1.

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