JP6027748B2 - Exhaust muffler device - Google Patents

Description

  The present invention relates to an exhaust muffler device provided with a catalyst device.

Conventionally, in an exhaust pipe connection structure that connects a front exhaust pipe and a rear exhaust pipe, the downstream end of the front exhaust pipe is enlarged and a metal pipe is press-fitted into this portion, and the front exhaust pipe and the rear pipe are positioned outside the metal pipe. The thing which prevented generation | occurrence | production of a back bead by welding a side exhaust pipe is known (for example, refer patent document 1).
Further, conventionally, in an exhaust purification device, a bulging portion that swells radially outward is formed at a welded portion of the cylindrical case that supports the catalytic device, and the back bead is welded to the bulging portion. What has been prevented from affecting the inside is known (for example, see Patent Document 2).

JP 02-161121 A JP 2009-150263 A

However, in the configuration of Patent Document 1, since the metal pipe is press-fitted into a portion where the downstream end of the exhaust pipe is enlarged, the structure becomes complicated. Further, in the configuration of Patent Document 2, since the bulging portion is formed, the structure is complicated, and when the bulging portion is exposed inside the cylindrical case, the bulging portion may affect the flow of the exhaust gas. There is. Further, when a catalyst device is added to the exhaust pipe as in Patent Document 1 to form an exhaust muffler provided with the catalyst device, the state inside the exhaust pipe on the upstream side of the catalyst device, in particular, the state of the welded portion can be confirmed. Is desirable.
The present invention has been made in view of the above-described circumstances, and in an exhaust muffler device equipped with a catalyst device, it is possible to prevent the occurrence of a weld back bead with a simple configuration and to provide an exhaust pipe upstream of the catalyst device. The purpose is to be able to check the internal state of the.

In order to achieve the above object, the present invention purifies exhaust gas to an exhaust pipe upstream portion (61A) connected to the exhaust port (55A) of the engine (13) and the exhaust pipe upstream portion (61A). In the exhaust muffler device including the catalyst device (63), the exhaust pipe upstream portion (61A) is connected to the exhaust port connection portion (72), the tubular tube portion (73), and the catalyst device (63). The connecting pipe portion (74) is welded and integrated into a small assembly (90), and the catalyst device (63) is formed on the outer periphery of the inner catalyst body (80) and the inner catalyst body (80). A holding mat (81) to be wound, and a cylindrical case (82) for holding the internal catalyst body (80) around which the holding mat (81) is wound, and the connecting pipe portion (74) The rear end (74B) and the catalyst device (63) And the case (82) are integrated and assembled by welding, and the thickness (T1) of the connecting pipe portion (74) is more than twice the thickness (T2) of the cylindrical case (82). In addition, it is formed smaller than the thickness of the holding mat (81) assembled to the cylindrical case (82), and the inner diameter (D1) of the rear end (74B) and the outer diameter (D2) of the internal catalyst body (80). Are formed in the same manner, and the end portion (84) of the cylindrical case (82) is provided with a reduced diameter portion (84A) in which the end portion (84) is reduced in diameter. as the ends (84) overlapping the outer periphery of the connecting tube portion (74), the rear end of the connecting tube portion (74) (74B) is fitted to the reduced diameter portion (84A), this from the outer circumference and outside and the front end of said reduced diameter portion (84A) of said connection tube portion with mating portions (74) Characterized in that it is tangent.
According to this configuration, the upstream portion of the exhaust pipe is formed as a small assembly in which the exhaust port connection portion, the tubular tube portion, and the connection pipe portion connected to the catalyst device are welded and integrated. The inner catalyst body and a cylindrical case for holding the inner catalyst body, and the rear end of the connecting pipe part and the cylindrical case of the catalytic device are assembled and integrated by welding, and the thickness of the connecting pipe part is Is formed thicker than the plate thickness of the cylindrical case, and the rear end of the connecting pipe portion and the catalyst device are welded so that the end of the cylindrical case overlaps the outer periphery of the connecting pipe portion. In the welded part between the rear end and the catalytic device, the thickness of the connecting pipe part can prevent the occurrence of a back bead with a simple configuration, and as a small assembly before welding the rear end of the connecting pipe part and the catalytic device. The inside of the formed upstream portion of the exhaust pipe can be confirmed.

In the above configuration, the catalyst device (63) is a ceramic catalyst device that is longer in the axial direction than in the radial direction, and is surrounded by a muffler body (66) that houses the catalyst device (63). It is good also as a structure.
In this case, since the periphery of the catalyst device is covered by the muffler main body, the catalyst device can be protected by the muffler main body and the muffler main body can be downsized even if the ceramic catalyst device is longer in the axial direction than in the radial direction. .

Further, wherein the exhaust pipe upstream part (61A), may be configured to outer pipe covering before Symbol exhaust pipe upstream portion (61A) from the outside (75) is further welded.
In this case, the exhaust pipe upstream portion, the exhaust pipe upstream part (61A) is the outer pipe is further welded to cover from outside Tei order, the state of the welded portion between the outer pipe and the exhaust pipe upstream portion, the connecting tube portion Can be confirmed before welding between the rear end and the cylindrical case, and since the muffler body is welded to the outer pipe, it can be welded after welding the rear end of the connecting pipe portion and the cylindrical case, Since the muffler body is downstream of the catalyst device, the back bead of the welded portion between the muffler body and the outer pipe can be allowed. For this reason, the exhaust muffler device which accommodates the ceramic catalyst device and is integrally formed by welding from the upstream portion of the exhaust pipe to the muffler body can be easily assembled to the vehicle body.

Furthermore, the exhaust pipe upstream part (61A) has a mounting hanger part (64) fixed to the vehicle body, and a fixing part for fixing the mounting hanger part (64) to the exhaust pipe upstream part (61A) by welding. (124), and the fixing portion (124) may be welded with a reinforcing plate (76) sandwiched between the exhaust pipe upstream portion (61A).
In this case, it is possible to prevent the occurrence of a back bead in the upstream portion of the exhaust pipe when the mounting hanger portion is welded to the reinforcing plate. For this reason, the workability of welding is good and productivity can be improved.
Further, the upstream end upstream end of (80A) and the retaining mat (81) of the inner catalyst (80) (81A), as the configuration you located in the same position in the axial direction of the tubular casing (82) Also good .

In the exhaust muffler device according to the present invention, the occurrence of a back bead can be prevented by the plate thickness of the connecting pipe portion at the welded portion between the rear end of the connecting pipe portion in the upstream portion of the exhaust pipe and the catalyst device, and the rear of the connecting pipe portion. Before welding the end and the catalyst device, the inside of the exhaust pipe upstream portion formed as a small assembly can be confirmed.
Further, since the periphery of the catalyst device is covered by the muffler body, even if the ceramic catalyst device is longer in the axial direction than in the radial direction, the catalyst device can be protected by the muffler body and the muffler body can be downsized.
Further, the state of the welded portion between the outer pipe and the exhaust pipe upstream portion can be confirmed before welding the rear end of the connecting pipe portion and the cylindrical case. Since the muffler body is welded to the outer pipe, it can be welded after welding the rear end of the connecting pipe part and the cylindrical case, and since the muffler body is downstream of the catalyst device, the muffler body and the outer pipe The back bead of the welded part can be allowed. For this reason, the exhaust muffler device which accommodates the ceramic catalyst device and is integrally formed by welding from the upstream portion of the exhaust pipe to the muffler body can be easily assembled to the vehicle body.

In addition, since the upstream portion of the exhaust pipe is formed when the mounting hanger portion is fixed to the upstream portion of the exhaust pipe by welding, the fixing portion of the mounting hanger portion is formed when the upstream portion of the exhaust pipe is formed as a small assembly. This can be confirmed before welding the rear end of the connecting pipe portion and the cylindrical case.
Furthermore, the fixing portion is welded with a reinforcing plate sandwiched between the upstream portion of the exhaust pipe, and the reinforcing plate is welded in advance before the mounting hanger portion is welded by the fixing portion. It can be confirmed before welding the rear end of the connecting pipe part and the cylindrical case, and the occurrence of a back bead in the upstream part of the exhaust pipe when the mounting hanger part is welded to the reinforcing plate can be prevented. For this reason, the workability of welding is good and productivity can be improved.

1 is a left side view of a motorcycle according to an embodiment of the present invention. It is a side view of an exhaust muffler device. It is sectional drawing of the rear part of an exhaust pipe. It is sectional drawing of a catalyst apparatus. It is a figure which shows the manufacturing process of a catalyst apparatus.

Hereinafter, a motorcycle including an exhaust muffler device according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a left side view of a motorcycle according to an embodiment of the present invention.
As shown in FIG. 1, a motorcycle 10 includes a front wheel 12 that can be steered by a handle 11 that is disposed at the front of the vehicle, an engine 13 that is a drive source disposed behind the front wheel 12, an engine 13 having a rear wheel 14 disposed behind 13 and driven by the engine 13 and a seat 15 disposed between the front wheel 12 and the rear wheel 14, and a passenger sitting on the seat 15 It is a riding type vehicle.

The body frame 40 of the motorcycle 10 includes a head pipe 41 that supports the front fork 16 that supports the front wheel 12 in a steerable manner, a main frame 42 that extends rearwardly downward from the head pipe 41 to the vehicle rear, and a rear portion of the main frame 42. A pair of left and right seat rails 43 extending rearward and rearward of the vehicle and a pair of left and right pivot plates 44 extending downward from the rear portion of the main frame 42 are provided.
The swing arm 18 that pivotally supports the rear wheel 14 is pivotally supported by the pivot plate 44 so as to be swingable. A rear cushion 19 is stretched between the rear part of the swing arm 18 and the rear part of the seat rail 43.

The motorcycle 10 is covered with a resin body cover 20. The vehicle body cover 20 is provided continuously from the front cover 21 covering the front surface of the vehicle, the rear portion of the front cover 21 to the rear portion of the vehicle, a pair of left and right side covers 22 covering the side surfaces of the vehicle, and the vehicle 13 An upper cover 25 covering the upper part and a pivot plate cover 27 covering the pivot plate 44 are provided.
A front fender 28 is disposed above the front wheel 12, and a handle cover 26 is disposed around the handle 11. A rear fender 29 is disposed above the rear wheel 14.

The engine 13 is supported by an engine stay (not shown) so as to be suspended from the main frame 42.
The engine 13 is a single-cylinder horizontal engine having a cylinder axis 54 extending substantially horizontally in the vehicle front-rear direction, and includes a crankcase 52, a cylinder block 53, and a cylinder head 55 in order from the vehicle rear side. A transmission (not shown) is integrally provided in the crankcase 52. The transmission pedal 56 is provided in the crankcase 52.
An output shaft 31 of the engine 13 projects from the left side surface of the crankcase 52. The rear wheel 14 is driven via a chain 34 wound between a drive sprocket 32 of the output shaft 31 and a driven sprocket 33 of the rear wheel 14.
A step stay 47 extending in the vehicle width direction is attached to the lower surface of the engine 13, and a step 48 for the driver is provided on the step stay 47.

Above the cylinder head 55, a throttle body 17 connected to an intake port of the cylinder head 55 is provided.
An exhaust muffler device 60 that extends to the rear of the vehicle through the right side of the vehicle opposite to the chain 34 is connected to the exhaust port 55 </ b> A formed on the lower surface of the cylinder head 55.

FIG. 2 is a side view of the exhaust muffler device 60.
As shown in FIGS. 1 and 2, the exhaust muffler device 60 includes an exhaust pipe 61 connected to the exhaust port 55 </ b> A and extending rearward, and a high-temperature and high-pressure exhaust gas connected to the exhaust pipe 61 and passing through the exhaust pipe 61. And a muffler 62 for discharging the pressure to the outside. The rear part of the exhaust pipe 61 extends into the muffler 62, and the catalyst device 63 for purifying the exhaust gas is provided at the rear part of the exhaust pipe 61 and accommodated in the muffler 62.
The exhaust muffler device 60 is fixed to the vehicle body side by bolts or the like via a front hanger part 64 (attachment hanger part) provided on the exhaust pipe 61 and a rear hanger part 65 provided on the muffler 62.

The muffler 62 has a main body case 66 (muffler main body) formed in a cylindrical shape having a larger diameter than the exhaust pipe 61, and the inner space of the main body case 66 is expanded by a plurality of partition walls 67 </ b> A and 67 </ b> B and a rear wall 68. It is a multistage expansion type partitioned into chambers X, Y, and Z. The front expansion chamber X and the rear expansion chamber Y communicate with each other by a first communication pipe 69 that passes through the central expansion chamber Z and penetrates the partition walls 67A and 67B. The expansion chamber Y and the expansion chamber Z are separated by the partition wall 67B. The expansion chamber Z communicates with the outside of the muffler 62 by a tail pipe 71 that penetrates the partition wall 67 </ b> B and the rear wall 68.
A tapered portion 66B having a smaller diameter toward the upstream end 66A side to which the exhaust pipe 61 is connected is formed at the front portion of the main body case 66.
The exhaust gas flows into the expansion chamber X from the exhaust pipe 61, flows into the expansion chamber Y through the first communication pipe 69, reverses the flow direction, and flows into the expansion chamber Z through the second communication pipe 70. Then, the flow direction is reversed again, and the liquid is discharged to the outside through the tail pipe 71.

FIG. 3 is a cross-sectional view of the rear part of the exhaust pipe 61.
As shown in FIGS. 2 and 3, the exhaust pipe 61 is formed in a single tubular shape extending in the front-rear direction by joining a plurality of pipes by welding.
The exhaust pipe 61 includes an exhaust port connection part 72 having a flange connected to the exhaust port 55A, a pipe part 73 (cylindrical pipe part) extending from the exhaust port connection part 72 to the catalyst device 63 side with substantially the same diameter, A downstream tapered pipe portion 74 (connection pipe portion) that extends from the pipe portion 73 and is connected to the catalyst device 63, and an outer pipe 75 that covers the pipe portion 73 from the outside with a gap between the pipe portion 73. The exhaust pipe upstream portion 61A has an exhaust pipe downstream portion 61B connected to the downstream end of the exhaust pipe upstream portion 61A. The exhaust pipe downstream portion 61 </ b> B includes a catalyst device 63 and a tapered pipe 88 and a pipe 89 connected to the downstream side of the catalyst device 63.

The downstream taper pipe portion 74 of the exhaust pipe upstream portion 61A includes a front side connection portion 74A fitted to the outer peripheral surface of the rear end 73A of the pipe portion 73, and a rear side connection portion 74B (connection pipe portion of the connection pipe portion) connected to the catalyst device 63. A rear end), and a tapered portion 74C that increases in diameter toward the downstream rear connection portion 74B side between the front connection portion 74A and the rear connection portion 74B. The front connection portion 74A is welded from the outside by the weld bead 121.
Further, the downstream tapered pipe portion 74 is formed so that a pair of half members 78A and 78B formed by press-molding a metal plate are welded at a mating surface 78C to form a conical pipe. For this reason, while being able to improve the freedom degree of a taper-shaped design, productivity can be improved.

The outer pipe 75 has an end 75A having a reduced diameter at the upstream end, and the end 75A fitted to the outer peripheral surface of the pipe 73 is welded and fixed. The end portion 75 </ b> A is welded from the outside by the weld bead 122. The downstream end of the outer pipe 75 is located in the vicinity of the rear end 73 </ b> A of the pipe portion 73.
An upstream end 66 </ b> A of the main body case 66 of the muffler 62 is welded to the outer peripheral surface 75 </ b> B of the outer pipe 75 from the outside by a weld bead 123. A space inside the tapered portion 66 </ b> B of the muffler 62 and the outer pipe 75 is an expansion chamber X.
A reinforcing plate 76 having a semicircular cross section is welded to the upstream side of the outer pipe 75 on the outer peripheral surface of the pipe portion 73. The front hanger portion 64 is fixed to the reinforcing plate 76 and the outer pipe 75 by welding from the outside with a weld bead 124 (fixed portion) (FIG. 2).

FIG. 4 is a cross-sectional view of the catalyst device 63.
As shown in FIGS. 3 and 4, the catalyst device 63 includes a cylindrical catalyst body 80 (internal catalyst body), a holding mat 81 wound around the outer periphery of the catalyst body 80, and the inside through the holding mat 81. A holding cylinder 82 (cylindrical case) that holds the medium 80 is provided.
The catalyst device 63 has a larger diameter than the exhaust pipe upstream portion 61A, and the exhaust gas flowing into the catalyst device 63 from the exhaust pipe upstream portion 61A is purified by the catalyst body 80 and the pressure is relieved.

  The catalyst body 80 is a honeycomb-like porous structure having a large number of pores extending along the axial direction inside the cylindrical outer shell, and has a large internal surface area. Platinum, rhodium and palladium for decomposing exhaust gas components are supported on the walls of the pores as catalysts. Since the base material of the catalyst body 80 is made of porous ceramics, it easily supports a catalyst such as platinum or rhodium. Here, as a preferable example of the material of the ceramic, various heat-resistant ceramics including cordierite, mullite, alumina, alkaline earth metal aluminate, silicon carbide, silicon nitride, or the like can be used. It is.

The holding mat 81 is formed by compressing or accumulating ceramic fibers into a long mat shape, wound around the outer surface of the catalyst body 80, and sandwiched between the catalyst body 80 and the holding cylinder 82. Is done. Since the holding mat 81 is an aggregate in which fibers are intertwined, it has a relatively large elasticity. Here, the material of the holding mat 81 may be any material having heat resistance and elasticity, and a material in which fibrous metals are integrated, glass wool, or the like can also be used.
The length of the holding mat 81 in a state of being wound around the catalyst body 80 is formed to be smaller than the length of the catalyst body 80 in the longitudinal direction (axial direction).

The material of the holding cylinder 82 is a metal having high strength and heat resistance, and for example, a steel material such as stainless steel can be used.
The holding cylinder 82 has a cylindrical straight portion 83 that extends in the axial direction with the same diameter, and a reduced diameter portion 84A that is formed at an upstream end portion 84 (end portion of the cylindrical case) of the exhaust gas. . The reduced diameter portion 84A is formed by reducing the diameter of the end of the straight portion 83 having the same thickness in the axial direction by drawing, and the outer diameter and the inner diameter are reduced. The total length of the holding cylinder 82 is longer than the total length of the catalyst body 80.

As shown in FIG. 4, the rear connection portion 74B of the downstream tapered pipe portion 74 of the exhaust pipe upstream portion 61A is fitted to the inner peripheral portion of the reduced diameter portion 84A and is welded from the outside by the weld bead 125. The position of the end face 85 of the rear connection part 74B substantially coincides with the position of the tip of the straight part 83.
In the present embodiment, the plate thickness T1 (plate thickness of the connecting pipe portion) of the rear connection portion 74B is set to be larger than the plate thickness T2 (plate thickness of the cylindrical case) of the reduced diameter portion 84A. Thus, by making the plate thickness T1 of the rear connection portion 74B inside the reduced diameter portion 84A thicker than the plate thickness T2 of the reduced diameter portion 84A, it is possible to prevent the occurrence of the back bead of the weld bead 125. Thereby, generation | occurrence | production of the back bead of the internal peripheral surface of the rear side connection part 74B through which exhaust gas passes can be prevented, and exhaust efficiency can be improved. Here, as an example, the plate thickness T1 is 2 mm, the plate thickness T2 is 1 mm, and the plate thickness T1 is preferably at least twice the plate thickness T2 in order to prevent the occurrence of back beads. Moreover, the plate | board thickness of the downstream taper pipe part 74 is uniform, and is the same thickness as plate | board thickness T1 over the whole.

The catalyst body 80 is assembled into the holding cylinder 82 by being press-fitted from the downstream end 83A opposite to the reduced diameter portion 84A in a state where the holding mat 81 is wound around the outer periphery.
The upstream end 80A of the catalyst body 80 and the upstream end 81A of the holding mat 81 are close to each other so as to be located at substantially the same position in the axial direction of the holding cylinder 82, and are spaced from the end face 85 of the rear connection portion 74B. It is inserted to the position where S is secured. The gap S is set as small as possible while preventing the end face 85 from contacting the catalyst body 80 in consideration of the dimensional tolerance and thermal expansion of each component.

Further, the inner diameter D1 of the rear connection portion 74B is formed substantially the same as the diameter D2 of the boundary portion 86 in the radial direction between the holding mat 81 and the catalyst body 80, and the inner peripheral surface 79 of the rear connection portion 74B. The boundary portion 86 is located at substantially the same position in the radial direction. Here, the diameter D <b> 2 coincides with the inner diameter of the holding mat 81 and the outer diameter of the catalyst body 80.
In this way, the exhaust gas flowing from the rear side connecting portion 74B to the catalyst body 80 is made by making the gap S as small as possible and making the inner diameter D1 of the rear side connecting portion 74B and the diameter D2 of the boundary portion 86 substantially the same. Can be made smooth. That is, the exhaust gas G flowing along the inner peripheral surface 79 of the downstream taper pipe portion 74 flows straight into the catalyst body 80 along the inner peripheral surface of the rear connection portion 74B, and the exhaust gas G flows in the holding mat 81. It is possible to prevent direct contact with the upstream end 81A. For this reason, the influence of the heat etc. which the exhaust gas G exerts on the holding mat 81 can be suppressed, the flow of the exhaust gas G can be made smooth, the exhaust efficiency can be improved and the engine performance can be improved.

Further, since the upstream end 80A of the catalyst body 80 and the upstream end 81A of the holding mat 81 are close to each other so as to be located at substantially the same position in the axial direction of the holding cylinder 82, the upstream end 80A and the upstream end 81A It is possible to prevent an unnecessary space from being formed in the gap S due to the deviation. For this reason, disturbance of exhaust gas can be prevented and engine performance can be improved.
Further, in the configuration in which the reduced diameter portion 84A is provided in the holding cylinder 82, and the rear connection portion 74B of the downstream tapered tube portion 74 is fitted to the reduced diameter portion 84A, the inner diameter D1 and the diameter D2 are substantially the same. Even when the holding mat 81 is thick, the downstream taper pipe portion 74 does not have to be thicker than necessary, and the weight can be reduced.

The total length of the catalyst body 80 is longer than the total length of the holding mat 81, and the upstream end 80 </ b> A and the upstream end 81 </ b> A are arranged in the axial direction, so the downstream end 81 </ b> B of the holding mat 81 is more than the downstream end 80 </ It can be prevented from protruding in the axial direction. For this reason, the holding mat 81 does not get in the way, and the workability of press fitting is good.
As shown in FIG. 3, a taper pipe 88 having a smaller diameter toward the downstream side of the exhaust is fitted and welded to the inner peripheral portion of the downstream end 83 </ b> A of the holding cylinder 82. A pipe 89 whose rear end is closed is connected to the downstream end of the tapered pipe 88, and the exhaust gas flows into the expansion chamber X through a plurality of small holes 89 </ b> A formed in the outer peripheral surface of the pipe 89. .

As shown in FIG. 2, the catalyst device 63 is formed longer in the axial direction than in the radial direction. However, since the periphery is covered by the main body case 66 of the muffler 62, the strength of the catalyst device 63 is strong. Can be secured sufficiently. In addition, since the catalyst device 63 is elongated, the muffler 62 can be reduced in the radial direction, and the exhaust muffler device 60 can be easily disposed even in a saddle-ride type vehicle having no space for placement.
Further, since the catalyst device 63 is housed in the main body case 66, the components arranged around the muffler 62 can be protected from the radiant heat of the catalyst device 63. Furthermore, since the single catalyst body 80 is disposed in the tapered portion 66B formed in the small diameter on the upstream side of the main body case 66, the catalyst body 80 can be quickly activated by the heat of the exhaust gas while reducing the size of the muffler 62. .

Here, the manufacturing process of the exhaust muffler device 60 will be described.
The exhaust muffler device 60 is assembled by connecting the main body case 66 after connecting the exhaust pipe downstream portion 61B having the catalyst device 63 and the exhaust pipe upstream portion 61A.
FIG. 5 is a diagram illustrating a manufacturing process of the catalyst device 63.
As shown in FIG. 5, first, a cylindrical substrate is coated with a solution of the catalyst composition by the coating apparatus 100, and is baked by the heating furnace 101, whereby the catalyst composition is fixed to the substrate, and the catalyst body. 80 is formed. The coating and baking steps are performed once or multiple times.
Next, in the press-fitting step, the holding mat 81 is wound around the catalyst body 80, and the catalyst body 80 and the holding mat 81 are press-fitted into the holding cylinder 82 from the downstream end 83A opposite to the reduced diameter portion 84A. Complete. Thereafter, a tapered pipe 88 welded integrally with the pipe 89 (FIG. 3) is fitted and welded to the inner peripheral portion of the downstream end 83A of the catalyst device 63.
Here, the coating and firing steps are described as being performed before the press-fitting step. However, the present invention is not limited to this, and the coating is performed only in the step after the press-fitting step or both before and after the press-fitting step. And firing may be performed.

As shown in FIG. 3, the exhaust pipe upstream portion 61 </ b> A includes an exhaust port connection portion 72 (FIG. 2), a pipe portion 73, a downstream tapered pipe portion 74, an outer pipe 75, a reinforcing plate 76, and a front hanger portion 64. Are prepared as a small assembly 90 formed by welding. At the stage where the small assembly 90 is formed, the presence or absence of the back beads of the welded portions of the weld beads 121, 122, and 124 and the reinforcing plate 76 is checked. If necessary, the back beads are removed.
Next, the rear connection portion 74 </ b> B of the downstream tapered pipe portion 74 of the small assembly 90 is fitted into the reduced diameter portion 84 </ b> A of the holding cylinder 82 and is welded by the weld bead 125. Here, since the plate thickness T1 of the rear connection portion 74B is set to be larger than the plate thickness T2 of the reduced diameter portion 84A, the occurrence of the back bead of the weld bead 125 can be prevented.

In the present embodiment, the exhaust pipe upstream portion 61A is formed as a small assembly 90, the inside of the exhaust pipe upstream portion 61A can be confirmed before the rear connection portion 74B is inserted into the reduced diameter portion 84A, and the rear In order to prevent the occurrence of the back bead of the weld bead 125 for welding the reduced diameter portion 84A and the small assembly 90 by increasing the plate thickness T1 of the side connection portion 74B, a back bead is formed in the pipe on the upstream side of the catalyst body 80. It can be prevented from being formed. For this reason, it is possible to prevent the back bead on the upstream side of the catalyst body 80 from dropping out and entering the catalyst body 80.
Further, since the front part of the front hanger part 64 is welded to the reinforcing plate 76 provided on the surface of the pipe part 73, the back bead at the front part of the weld bead 124 is formed inside the pipe part 73. Can be prevented. Further, the rear part of the front hanger part 64 is welded to the outer pipe 75, but the inside of the outer pipe 75 is located downstream of the catalyst body 80 in the flow of exhaust gas, so that a rear bead at the rear part of the weld bead 124 is generated. Is acceptable. For this reason, welding is easy.

  After the small assembly 90 and the catalyst device 63 are welded with the weld bead 125, the rear portion of the exhaust pipe upstream portion 61A and the catalyst device 63 are inserted into the main body case 66 of the muffler 62, and the upstream end 66A of the main body case 66 is connected to the outer pipe. The outer peripheral surface 75 </ b> B of 75 is fitted and welded by the weld bead 123. Since the main body case 66 is welded to the outer pipe 75 located downstream of the catalyst body 80 in the flow of exhaust gas, generation of the back bead of the weld bead 123 can be allowed. For this reason, welding is easy.

  As described above, according to the embodiment to which the present invention is applied, the exhaust pipe upstream portion 61A includes the exhaust port connection portion 72, the pipe portion 73, and the downstream tapered pipe portion 74 connected to the catalyst device 63. The catalyst device 63 includes a catalyst body 80 and a holding cylinder 82 that holds the catalyst body 80, and is connected to the downstream connection portion 74 </ b> B of the downstream tapered pipe portion 74 and the catalyst. The holding cylinder 82 of the device 63 is integrated and assembled by welding, and the plate thickness T1 of the rear side connecting portion 74B of the downstream tapered pipe portion 74 is formed thicker than the plate thickness T2 of the reduced diameter portion 84A of the holding cylinder 82. At the same time, the rear connection portion 74B of the downstream taper tube portion 74 and the holding tube 82 of the catalyst device 63 are welded so that the end portion 84 of the holding tube 82 overlaps the outer periphery of the downstream taper tube portion 74. With part 74B In the weld bead 125, which is a welded portion with the holding cylinder 82, the occurrence of the back bead can be prevented by the plate thickness T 1 of the rear connection portion 74 B, and before the rear connection portion 74 B and the holding cylinder 82 are welded, The inside of the exhaust pipe upstream portion 61A formed as the body 90 can be confirmed. Thereby, it is possible to prevent the back bead on the upstream side of the catalyst body 80 from dropping out and entering the catalyst body 80.

Further, since the periphery of the catalyst device 63 is covered by the main body case 66 of the muffler 62, even if the catalyst device 63 includes the ceramic catalyst body 80 that is longer in the axial direction than in the radial direction, the catalyst device 63 is attached to the main body case 66. The muffler 62 can be downsized.
Further, the outer pipe 75 is further welded to the exhaust pipe upstream portion 61A before welding the rear connection portion 74B of the downstream taper pipe portion 74 and the holding cylinder 82, and the outer pipe 75 and the body case 66 are After welding of the side connection portion 74B and the holding cylinder 82, they are integrated and assembled by welding. Therefore, the state of the back bead of the weld bead 122 of the outer pipe 75 is changed to that before welding of the rear connection portion 74B and the holding cylinder 82. In addition, since the main body case 66 is welded to the outer pipe 75, the main body case 66 can be welded after the rear connection portion 74B and the holding cylinder 82 are welded. Therefore, the back bead of the weld bead 123 that is a welded portion between the main body case 66 and the outer pipe 75 can be allowed. Therefore, it is possible to easily assemble the exhaust muffler device 60 which accommodates the catalyst device 63 including the ceramic catalyst body 80 and is integrally formed by welding from the exhaust pipe upstream portion 61A to the main body case 66 to the vehicle body. it can. Further, since the exhaust muffler device 60 can be integrally formed by welding from the exhaust pipe upstream portion 61A to the main body case 66, the appearance can be improved.

Further, the exhaust pipe upstream portion 61A has a front hanger portion 64 fixed to the vehicle body, and a weld bead 124 that fixes the front hanger portion 64 to the exhaust pipe upstream portion 61A by welding includes the exhaust pipe upstream portion 61A. Since it is formed when forming as a small assembly 90, the back bead of the weld bead 124 of the front hanger part 64 is confirmed before welding the rear connection part 74B of the downstream tapered pipe part 74 and the holding cylinder 82. be able to.
The weld bead 124 is welded with a reinforcing plate 76 sandwiched between the pipe 73 of the exhaust pipe upstream portion 61A, and the reinforcing plate 76 is previously piped before the front hanger portion 64 is welded with the weld bead 124. Since it is welded to the portion 73, the back bead of the welded portion of the reinforcing plate 76 can be confirmed before welding the rear connecting portion 74B and the holding cylinder 82, and the front hanger portion 64 is connected to the reinforcing plate 76. It is possible to prevent the occurrence of the back bead of the weld bead 124 to be welded. For this reason, the workability of welding is good and productivity can be improved.

In addition, the said embodiment shows the one aspect | mode which applied this invention, Comprising: This invention is not limited to the said embodiment.
In the above embodiment, the reduced diameter portion 84A is described as being formed by reducing the diameter of the end of the straight portion 83 by drawing, but the present invention is not limited to this. For example, the reduced diameter portion may be formed by reducing the inner diameter of the straight portion 83 by fitting a pipe-like spacer to the inner peripheral portion at the end of the straight portion 83.

13 Engine 55A Exhaust port 60 Exhaust muffler device 61A Exhaust pipe upstream part 63 Catalytic device 64 Front hanger part (mounting hanger part)
66 Body case (muffler body)
72 Exhaust port connection part 73 Pipe part (tubular pipe part)
74 Downstream taper pipe (connecting pipe)
74B Rear connection part (rear end of connection pipe part)
75 Outer pipe 76 Reinforcement plate 80 Catalyst body (internal catalyst body)
82 Holding cylinder (tubular case)
84 End (end of cylindrical case)
90 Small assembly 124 Weld bead (fixed part)
T1 thickness (thickness of connecting pipe)
T2 thickness (thickness of cylindrical case)

Claims (5)

An exhaust muffler device comprising an exhaust pipe upstream portion (61A) connected to the exhaust port (55A) of the engine (13) and a catalyst device (63) for purifying exhaust gas to the exhaust pipe upstream portion (61A) In
The exhaust pipe upstream part (61A) is integrally formed by welding an exhaust port connection part (72), a tubular pipe part (73), and a connection pipe part (74) connected to the catalyst device (63). Formed as a simplified subassembly (90),
The catalyst device (63) includes an inner catalyst body (80), a holding mat (81) wound around the outer periphery of the inner catalyst body (80), and the inner contact where the holding mat (81) is wound around the outer periphery. A cylindrical case (82) holding the medium (80);
The rear end (74B) of the connecting pipe part (74) and the cylindrical case (82) of the catalyst device (63) are integrated and assembled by welding,
A holding mat (81) having a plate thickness (T1) of the connecting pipe portion (74) more than twice the plate thickness (T2) of the cylindrical case (82) and assembled to the cylindrical case (82) The inner diameter (D1) of the rear end (74B) and the outer diameter (D2) of the internal catalyst body (80) are formed to be the same, and the end of the cylindrical case (82) is formed. The portion (84) is provided with a reduced diameter portion (84A) in which the end portion (84) is reduced in diameter, and the end portion (84) of the cylindrical case (82) is an outer periphery of the connecting pipe portion (74). so as to overlap, the rear end of the connecting tube portion (74) (74B) is the fitted into the reduced diameter portion (84A), the outer periphery and the contraction of the connecting tube portion in the fitting portion (74) An exhaust muffler device, wherein the front end of the diameter portion (84A) is welded from the outside .   The catalyst device (63) is a ceramic catalyst device that is longer in the axial direction than in the radial direction, and is surrounded by a muffler body (66) that houses the catalyst device (63) therein. Item 2. An exhaust muffler device according to Item 1.   The exhaust muffler device according to claim 2, wherein an outer pipe (75) covering the exhaust pipe upstream portion (61A) from the outside is further welded to the exhaust pipe upstream portion (61A).   The exhaust pipe upstream part (61A) has a mounting hanger part (64) fixed to the vehicle body, and a fixing part (124) for fixing the mounting hanger part (64) to the exhaust pipe upstream part (61A) by welding. The fixing portion (124) is welded to the exhaust pipe upstream portion (61A) with a reinforcing plate (76) sandwiched between the fixing portion (124) and the exhaust pipe upstream portion (61A). The exhaust muffler device described. The upstream end of the upstream end (80A) and the retaining mat (81) of the inner catalyst (80) (81A) is a feature and Turkey be located in the same position in the axial direction of the tubular casing (82) The exhaust muffler device according to any one of claims 1 to 4.

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