JPH1162572A - Catalytic converter and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a catalyst support to be surely supported by obviating the deformation of a casing so effectively even at the time of a high temperature. SOLUTION: A catalyst support 15 is stored in a casing 11 making both vertical halved cases back-to-back, and a sealing member 20 is set up in an airspace between a tubular part of this catalyst support 15 and a tubular part wall inner circumferential surface of the casing, while angular parts at both ends in the axial direction of this catalyst support regulate position in each axial direction by caps 21 via buffer members 25. Each of the caps 21 is formed into a C-shape after cutting a ring part, and it is fixed to the casing 11 by means of plug welding in a state that the halved cases are pressurized so as to impart the specified compression to the sealing member. As the cap is of the C-shape, deformation in the cap at the time of pressurization is easy and simultaneously, after the plug welding, excellent shape holdability inherent in the casing is secured, so that the thermal deformation in the casing is checked even in the case of a high temperature, and thus scattering of the sealing member is prevented from occurring.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a catalytic converter mounted on an exhaust system of a vehicle and a method of manufacturing the same.

[0002]

2. Description of the Related Art A catalytic converter for purifying exhaust gas is mounted on an exhaust system of an automobile. Although this catalytic converter has a catalyst carrier housed in a cylindrical casing, it receives vibration and thermal load during operation of the vehicle, so it is necessary to support it so that the catalyst carrier is not damaged by these. . As a catalytic converter having such a catalyst carrier storage / holding structure, the present applicant has previously disclosed in Japanese Patent Laid-Open No.
There is one proposed in Japanese Patent No. 0551.

[0003] This is to absorb even if there is a variation in the quality of the axial size of the catalyst carrier, and a seal member is wound around the peripheral surface of the catalyst carrier in a cylindrical casing, and the shaft is removed. An annular cap is set at both ends in the direction via a buffer member, and the cylindrical portion of the casing and the annular cap are plug-welded while the annular cap is pressed by a pressing jig. The annular cap has a basic shape including an inward flange portion for pressing the catalyst carrier in the axial direction and a cylindrical portion for welding and fixing to the casing. As a result, a stored and held state of the catalyst carrier in which a predetermined compressed state is secured in the axial direction is obtained.

[0004]

In the above proposed catalytic converter, the casing is divided into upper and lower halves, the catalyst carrier, the buffer member and the annular cap are set in the lower half case, and then the upper half case is moved to the uppermost half. Assemble by centering and welding the side edges. However, since an annular cap is used here, the dimension in the cylinder radial direction of the completed casing is substantially determined by the diameter of the annular cap, and the peripheral surface of the catalyst carrier is sealed against the radial variation of the catalyst carrier. There was still a lack of certainty in maintaining the compressed state of the members in an appropriate range.

[0005] In particular, in a catalytic converter which is often mounted immediately below the exhaust manifold of an engine, both the catalyst carrier and the casing become hot, and therefore the amount of thermal deformation of the casing is large. Since the annular cap is generally formed of a relatively thin plate having substantially the same thickness of the inward flange portion and the cylindrical portion, the annular cap is pulled by the large thermal deformation of the axially central portion of the casing, and is not limited to the central portion. It is difficult to effectively suppress deformation of the end provided with the annular cap.

If the seal member on the peripheral surface of the catalyst carrier is scattered due to the thermal deformation of the casing, unpurified exhaust gas may be discharged by bypassing the catalyst carrier. The seal itself may be lost due to loss of holding by the seal member. Accordingly, an object of the present invention is to provide a catalytic converter in which deformation of a casing is effectively prevented even at a high temperature so that a catalyst carrier is reliably held even in view of the above problems.

[0007]

According to a first aspect of the present invention, there is provided a catalytic converter having a cylindrical casing for accommodating a catalyst carrier with a seal member interposed therebetween. An L-shaped cross-section cap consisting of a flange portion facing the end face corner of the support and a cylindrical portion on the casing wall is provided between the flange and the end face corner of the catalyst support via a buffer member, and the cap is free. In the state, the ring has a C shape in which a part of the ring is cut, and in the installed state, the ends of the C shape are connected to each other via plug welding of the cylindrical portion and the casing.

The thickness of the flange of the cap is preferably larger than the thickness of the cylinder.

According to a third aspect of the present invention, there is provided a catalyst carrier comprising a seal member wound around the periphery thereof, and a C-shaped cap having an L-shaped cross section comprising a flange portion and a cylindrical portion covered at both ends via a buffer member. A first step of setting between the half cases, and a second step of pressurizing the half cases so that the sealing member is in a predetermined compressed state, and then welding the half cases together to form a casing. And a third step of fixing the cap to the casing by plug welding thereafter.

[0010] The third step may include a step of connecting the C-shaped ends of the cap to each other by plug welding. In the third step, it is preferable that the above-described plug welding is further performed in a state where caps covering both ends of the catalyst carrier are pressed in the axial direction so that the buffer member is in a predetermined compressed state.

[0011]

In the catalytic converter according to the first aspect, when the casing member is pressurized in order to bring the seal member into a predetermined compressed state, the cap is formed in a C shape having a cut portion, so that deformation is easy. Since the ends of the C shape are connected to each other at the same time as the plug welding of the cap, a high shape retention property of the casing is obtained thereafter, and thermal deformation of the casing is prevented even when the temperature of the catalytic converter becomes high.
Further, by making the thickness of the flange portion of the cap larger than the thickness of the cylindrical portion, the rigidity in the radial direction of the cap is increased, so that the thermal deformation of the casing is more effectively prevented.

According to the third aspect of the present invention, when the half-split case is pressed in the second step, the cap has a cut portion.
The casing is easily deformed because of its shape, and the casing in which the sealing member is in a predetermined compressed state is easily formed. In addition, a third method for fixing the cap to the casing by plug welding is provided.
By simultaneously connecting the C-shaped ends of the cap to each other in the step, the shape of the casing in which the sealing member is in a predetermined compressed state is securely held, and thermal deformation of the casing is also prevented. Further, by performing the plug welding in the third step in a state where the cap is pressed in the axial direction so that the cushioning member is in a predetermined compressed state, the catalyst carrier is also stably held in the axial direction.

[0013]

Next, an embodiment of the present invention will be described.
An embodiment applied to a manifold catalytic converter directly connected to an exhaust manifold of an engine will be described. FIG. 1 is an external view showing a state in which the manifold catalytic converter of the embodiment is connected to an exhaust manifold, FIG. 2 is a longitudinal sectional view showing the configuration of the manifold catalytic converter of the embodiment in a horizontal position, and FIG. 3 is used in the embodiment. FIG. 4 is a perspective view of the cap, and FIG. 4 is a sectional view of the cap. As shown in FIG. 1, the exhaust manifold 1 includes a manifold flange 2 attached to a cylinder head (not shown), and a collecting portion 4 in which a plurality of branch pipes 3 extending from the manifold flange 2 are joined. The exhaust manifold 1 is directly connected to the collecting portion 4 by welding.

The manifold catalytic converter 10 is provided with a cylindrical casing 11 which is divided into upper and lower halves in FIG. 2, and a lower half case 13 and an upper half case 12 are centered. As shown in FIG. 2, a catalyst carrier 15 is accommodated in the cylindrical casing 11, and a catalyst carrier 1 is provided between the cylindrical portion of the catalyst carrier 15 and the inner peripheral surface of the cylindrical wall of the casing.
5, a seal member 20 such as an interram mat (trade name) wound around the entire circumference is disposed. Further, the corners at both ends in the axial direction of the catalyst carrier 15 are respectively
1 restricts the position in the axial direction via the buffer member 25.

As shown in FIG. 4, the cap 21 has an L-shaped cross section composed of a cylindrical portion 22 and a flange portion 23 extending inward from the cylindrical portion 22 on the cylindrical portion wall of the casing 11. Is twice as thick as the cylindrical portion 22. In the present embodiment, as shown in FIG. 3, the cap 21 has a C shape in which a ring-shaped part is cut, and is fixed to the casing 11 by plug welding at a plurality of locations. Then, each end 2 of the C-shaped cut portion
4, 24 are connected to each other by one of the plug welds.

Next, the manifold catalytic converter 1
0 will be described. First, the lower jig 31
(See FIG. 5), the lower half case 13 is set, and then the catalyst carrier 15 with the seal member 20 wound therearound and caps 21 covered at both ends via the buffer members 25 is placed on the lower half case 13. Set to 13 in the split case. The upper half case 12 is placed on this, and the centering is performed. At this time, each of the caps 21, 21 has a cut hole (end 24, 24) with a welding hole 17 provided at a position slightly offset from the mating surface of the upper and lower half cases 12, 13.
Is set to match.

The upper and lower half cases 12 and 13 accommodating the catalyst carrier 15 are then sandwiched between a lower jig 31 and an upper jig 30 as shown in FIG. , 13 and the catalyst carrier 15, that is, the gap in the installation space of the seal member 20 is pressurized so as to have a predetermined value. In this pressurized state, the mating surfaces 14 of the upper and lower half cases 12 and 13 are butt-welded over the entire length in the axial direction. As a result, an intermediate assembly is obtained in which the sealing member 20 between the casing 11 formed by the half cases 12 and 13 and the catalyst carrier 15 is appropriately compressed. In this intermediate assembly, the C-shaped cap 21 is also pressed and compressed together with each of the half cases 12 and 13 so that the ends 24 of the cut portions are close to each other.

The intermediate assemblies taken out of the upper and lower jigs 30, 31 are then set on axial pressing jigs 33, 34 as shown in FIG. Apply pressure. Then, the cap 21 is plug-welded to the casing 11 in a state where the compression state of the buffer members 25 at both ends of the catalyst carrier 15 is pressurized so as to be a predetermined value. Thereby, the cap 21 is fixed in a state where the catalyst carrier 15 is pressed with the predetermined surface pressure from both sides in the axial direction via the buffer member 25. In addition, the cap 2 is formed by the plug welding.
1, the cut portions which are close to each other, that is, both ends 2 of the C shape
4 and 24 are also connected to each other via the casing 11.

In this way, the manifold catalytic converter 10 in which the catalyst carrier 15 is accommodated and held in the casing 11 is provided.
Is obtained. One end of the manifold catalytic converter 10 is welded to the collecting portion 14 of the exhaust manifold 1, and the other end is connected to an exhaust pipe (not shown) connected to the muffler.

The present embodiment is configured as described above. The exhaust gas flowing from the exhaust manifold 1 is purified by reacting and burning while passing through the catalyst carrier 15 of the manifold catalytic converter 10. Then, when forming the casing, the jig 3
Half-split case 1 with pressure applied in the direction perpendicular to the axis at 0, 31
By welding the second and the 13, the seal member 20 between the casing 11 and the catalyst carrier 15 is appropriately compressed, and the cap 21 is pressed with the casing 21 while being pressed by the axial pressing jigs 33 and 34. Since a predetermined pressing state is ensured in the axial direction of the catalyst carrier 15 by plug welding to the catalyst carrier 11, the catalyst carrier 15 is stably held.

Further, since the cap 21 has a C-shape having a cut portion, the cap 21 can be easily deformed when the casing 21 is pressurized in the direction perpendicular to the axis when the casing is formed. Obtained reliably. Then, since the cut portion is joined at the same time as the plug welding of the cap 21, thereafter, the casing 11 has high shape retention. Furthermore, since the thickness of the flange portion 23 of the cap 21 is particularly large and the rigidity in the radial direction is high, even if the temperature of the manifold catalytic converter becomes high, abnormal heat deformation of the casing 11 is prevented by the cap 21, and the sealing member 20 This has the effect that scattering is prevented.

In the embodiment, upper and lower half cases 1
After forming the casing 11 by welding the casings 2 and 13, the cap is pressed in the axial direction. However, the invention is not limited to this. When the casing is formed by pressing the half case, the cap is simultaneously compressed in the axial direction. It may be performed while doing. Although the embodiment has been described with respect to an example in which the present invention is applied to a manifold catalytic converter, the present invention can be similarly applied to a catalytic converter installed further downstream of an exhaust pipe. At that time, a diffuser portion having a funnel-shaped cross section for connection to an exhaust pipe is welded to the end of the cylindrical casing described in the embodiment.

[0023]

As described above, the catalytic converter according to the present invention comprises a cylindrical casing for accommodating a catalyst carrier with a sealing member interposed therebetween. C to be installed
Because of the shape, the cap 21 is easily deformed under pressure to bring the seal member into a predetermined compressed state. Since the ends of the C shape are connected to each other with plug welding of the cap, high shape retention of the casing is obtained, and thermal deformation of the casing is prevented even when the temperature of the catalytic converter becomes high. Thereby, there is an effect that occurrence of scattering of the seal member is also prevented.

Further, by making the thickness of the flange portion of the cap larger than the thickness of the cylindrical portion, the rigidity in the radial direction of the cap is increased, so that the heat deformation of the casing is more effectively prevented.

Further, according to the production method of the present invention, a catalyst carrier in which a seal member is wound around the periphery and a C-shaped cap having an L-shaped cross section composed of a flange portion and a cylindrical portion is covered at both ends via a buffer member, A first step of setting between the half cases, and a second step of pressurizing the half cases so that the sealing member is in a predetermined compressed state, and then welding the half cases together to form a casing. And the third step of fixing the cap to the casing by plug welding thereafter, so that when the half-split case is pressed in the second step, the cap is easily deformed due to the C shape, This has the effect that a casing with the seal member in a predetermined compressed state can be easily formed.

Further, in the third step of fixing the cap to the casing by plug welding, the C-shaped ends of the cap are connected to each other at the same time, so that the shape of the casing in which the sealing member is in a predetermined compressed state is ensured. , And thermal deformation of the casing is also prevented. Further, by performing the plug welding in the third step in a state where the cap is pressed in the axial direction so that the buffer member is in a predetermined compressed state, the catalyst carrier is also stably held in the axial direction.

[Brief description of the drawings]

FIG. 1 is a diagram showing the appearance of an embodiment applied to a manifold catalytic converter.

FIG. 2 is a longitudinal sectional view showing a configuration of the embodiment.

FIG. 3 is a perspective view of a cap.

FIG. 4 is a sectional view of a cap.

FIG. 5 is an explanatory view showing a step of forming a casing.

FIG. 6 is an explanatory view showing a cap fixing step.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Exhaust manifold 2 Manifold flange 3 Branch pipe 4 Collecting part 10 Manifold catalyst converter 11 Casing 12, 13 Half case 14 Fitting surface 15 Catalyst carrier 17 Welding hole 20 Seal member 21 Cap 22 Tubular part 23 Flange part 24, End part 25 Buffer Member 30 Upper jig 31 Lower jig 33, 34 Axial pressing jig

Claims (5)

[Claims] 1. A catalytic converter comprising a tubular casing (11) for accommodating a catalyst carrier (15) with a sealing member (20) interposed therebetween, wherein the casing (11) has an end face of the catalyst carrier (15). A cap 21 having an L-shaped cross section comprising a flange portion (23) facing the corner portion and a cylindrical portion (22) on the casing wall is provided.
The cap (21) is installed between the flange portion and the end face corner portion of the catalyst support via a buffer member (25). The cap (21) has a C shape in which a part of a ring is cut off in a free state, and in the installed state. Through the plug welding of the cylindrical portion (22) and the casing (11), the C-shaped end portion (24,
24) are coupled to each other. 2. A flange portion (2) of the cap (21).
3. The catalytic converter according to claim 1, wherein the plate thickness of 3) is larger than the plate thickness of the cylindrical portion. 3. A sealing member (20) is wrapped therearound, and a C-shaped cap (21) having an L-shaped cross section comprising a flange portion (23) and a cylindrical portion (22) is provided at both ends with a cushioning member (25).
The catalyst carrier (15) covered via
A first step of setting between 2 and 13), and pressing the half cases (12, 13) so that the sealing member (20) is in a predetermined compressed state, and welding the half cases to each other in this state. And a third step of fixing the cap (21) to the casing (11) by plug welding. 4. The catalyst according to claim 3, wherein the third step includes a step of connecting the C-shaped ends (24, 24) of the cap (21) to each other by the plug welding. Converter manufacturing method 5. The method according to claim 3, wherein the third step is performed by using the buffer member (2).
The plug welding is performed in a state in which the cap (15) covering both ends of the catalyst carrier (15) is pressed in the axial direction so as to be in a predetermined compressed state. Or the method for producing a catalytic converter according to 4.