JPH0333894B2 - - Google Patents

Description

[Detailed Description of the Invention] A. Purpose of the Invention (Field of Industrial Application) The present invention provides a cushion material for a catalytic converter that elastically holds an integrally formed honeycomb catalyst carrier within a converter case, and a method for manufacturing the same. It is an invention that can be used.

(Prior Invention) Catalytic converters are widely used to oxidize or reduce harmful components such as carbon monoxide, hydrocarbons, and nitrogen oxides contained in the exhaust gas of automobile engines to render them harmless.

There are two types of catalyst carriers used in this converter: granular ones and honeycomb-shaped ones that are integrally formed with a large number of small holes. The present invention provides an effective structure and manufacturing method for a cushion material for elastically retaining the cushion material in contact with the converter case.

FIG. 1 schematically shows a converter using a conventional honeycomb catalyst carrier. Reference numeral 1 denotes a converter case having an exhaust inlet 2 and an exhaust outlet 3, and holds a corner of a honeycomb catalyst carrier 5 via an annular cushion material 4 at stepped portions 1a, 1a formed at both ends.

Since the cushion material 4 elastically holds the catalyst carrier 5, which becomes hot, inside the converter case 1, it is necessary to have heat resistance and elasticity, and airtightness to prevent short-circuiting of the exhaust gas. . To this end, conventional methods have been to knit a long material tube by knitting thin stainless steel wire, cut it to a predetermined length, and wrap it in a ring (sock wrap or bag wrap). The cushion material 4 was formed by pressure molding. In addition to stainless steel, Inconel, nickel, tungsten, etc. can be used.

However, in this way, the cushion material 4
In order to manufacture socks, it was not possible to automate the wrapping of socks, and the wrapping was done by hand, which took a lot of time and was inefficient.

On the other hand, in order to eliminate the inefficiency of manual manufacturing, a method of mechanizing manufacturing was proposed.
It is disclosed in Publication No. 53-40118. The method shown here is to make a cushion material by stacking a plurality of cylindrical knitted wire meshes concentrically and compressing them into an annular shape. (a) A method of flattening a cylindrical stockinette wire mesh made with another stockinette knitting machine and placing it in the center of a normal cylindrical stockinette knitting machine, (b)
A method is shown in which two or more normal stockinette knitting machines (for example, two machines) are placed one above the other, and the cylindrical wire mesh knitted by the upper stockinette knitting machine is layered into the cylindrical wire mesh knitted by the lower stockinette knitting machine. has been done.

Further, a cushion material in which a plurality of cylindrical knitted wire meshes are stacked concentrically and compressed to form an annular shape, and a method for manufacturing the same, are described in JP-A-56-3333 and are well known. In addition, cushion materials that use a cylindrical knitted wire mesh to hold a honeycomb catalyst carrier are described in JP-A-55-128613 and JP-A-55-164714; and the casing, and is different from the one that holds the corners of the carrier.

(Problems to be solved by the invention) The method described in Japanese Patent Application Laid-Open No. 53-40118 includes the following:
There are the following inconveniences.

(1) In order to make the manufactured cushion material have a predetermined density, the stacked wire mesh must be lengthened to increase the degree of compression, or the number of stacked cylindrical wire meshes must be increased.

If you make the stacked wire mesh long, it will buckle when compressed, so you cannot make it too long, so you have to increase the number of stacked wire meshes.In this case, with method (a) above, method (b) requires multiple stockinette knitting machines above and below,
Either method results in high costs.

(2) In addition, in order to insert another stockinette knitted wire mesh into the center of the stockinette knitted wire mesh, the diameter of the hook of the stockinette knitting machine must be changed little by little.

(3) As mentioned above, expensive equipment must be used, and one equipment can only produce products of a single diameter.

(4) The density of the product cannot be changed locally.

The manufacturing method of the cushion material and the product of the cushion material disclosed in JP-A No. 56-3333 involve wrapping each cylinder in a bag of cylindrical wire mesh, which is a manual process that cannot be automated by machines and is therefore inefficient and costly. The process is inefficient as it has to be done for each wire mesh, and the density distribution of the product cannot be changed.

B. Structure of the Invention (Means for Solving Problems) This invention provides that an annular cushion material having a cross-sectional shape that matches the corners of a honeycomb catalyst carrier and holds it in a casing has heat resistance and elasticity. A core material made of stockinette-knitted thin wire with a handle is wrapped around a rope-shaped core material, and a wire mesh made of the same stockinette-knitted material cylinder as above folded flat is attached vertically to the outside of the core material. As a result, a cushion material for a catalytic converter that retains the corners of a carrier without the disadvantages of the cushion materials according to the prior art described above was obtained, and a thin wire having heat resistance and elasticity is knitted with stockinette. A core material made by squeezing a long tube of material into a rope shape, and on the outside of the core material, one or more layers of long wire mesh made by knitting similar fine wires into a tube shape and folding them flat is placed lengthwise, and then tied and attached. A method for producing the cushion material for a catalytic converter as described above, in which a rope-like material of 100 mm is cut to a required length, formed into an annular shape, and press-formed into a predetermined cross section to hold the corners of the honeycomb catalyst carrier in a casing. This is what I got.

(Function) Since the cushion material for a catalytic converter and the manufacturing method thereof of the present invention are configured as described above,
A cushion material having a predetermined cross-section can be obtained by firmly joining the core material and the flat material tube attached longitudinally to the core material using a simple drawing device and pressing the core material.

(Example) Figures 2 and below show embodiments of the present invention.

Figure 2 shows the process of forming two layers of wire mesh around the core material, aligning the length direction of the core material and wire mesh, wrapping the core material, and wrapping the material lengthwise. The core material is made by folding a cylindrical wire mesh made of knitted stainless steel wire flat and drawing it through a die into a rope shape with a circular cross section.The density can be changed by changing the degree of drawing depending on the application (i.e. or soft) to form. Alternatively, a stockinette-knitted cylindrical wire mesh may be squeezed to form a core material without being flattened. 7 is a long wire mesh that serves as the inner layer, which is made by folding thin stainless steel wire stockinette-knitted into a cylindrical shape, and wraps the core material 6 lengthwise, with both edges overlapped. It is drawn into the die 8 and applied around the core material 6 to form an intermediate material 9. The intermediate material 9 that has come out of the die 8 has a rope shape with a circular cross section, in which the wire mesh 7 is vertically overlapped and wound around the core material 6. 10 is a long wire mesh that becomes the outer layer.
It is similar to the wire mesh 7 which becomes the inner layer, and is wrapped around the intermediate material 9 lengthwise, with both edges overlapped, drawn into the die 11, and applied to the intermediate material 9. The overlapped edges of the wire mesh 10 are located on the opposite side from the edge of the wire mesh 7. Reference numeral 12 denotes a rope-shaped material with a circular cross section, which is wrapped around the intermediate material 9 in a longitudinally overlapping manner with the wire mesh 10. The above process proceeds by pulling the material 12 to the left in FIG.
10 are strongly pressed to intertwine the stitches and are firmly connected.

The wire mesh 7 and 10 are thus attached and bonded in two layers vertically around the core material 6, and the rope-shaped material 12 is cut to an appropriate size and bent into an annular shape as shown in Fig. 3. Next, this is press-molded to complete a cushion material 4 having a cross-sectional shape as shown in FIG. In this case, the cushion material 4 has a ring shape with separate abutments, but it has been found that there is no problem in terms of characteristics by selecting a material 12 with an appropriate length for the circumference of the honeycomb catalyst carrier. .

In addition, if necessary, the mating portion 13 may be spot welded, or a short tube 14 of wire mesh may be attached to the mating portion 13 as shown in FIG.
It is also possible to cover the material 12 and fit it to both ends of the material 12, spot weld the material 12 and the short tube 14 to form a ring, and then press-form the ring to form the cushion material 4.

In the example shown in FIG. 2, the material 12 is made by covering the core material 6 with wire meshes 7 and 10 in two layers, and the overlapping edges of each wire mesh are shifted by 180 degrees, but the core material 6
The number of wire meshes to be stacked and the way in which their edges are stacked can be combined in various ways depending on the purpose, as shown below.

FIG. 5 is a cross-sectional view of the material 12 showing several examples of how wire mesh is wound around the core material 6. FIG. 90
Figure 5B shows the core material 6.
Place three layers of wire mesh 15, 16, 17 on the overlapping edges.
Figure 5 C, which is wound at 120 degree intervals, is
Four layers of wire mesh 15, 16, 17, 18 are wrapped with the overlapping edges shifted by 180 degrees, Fig. 5D
In this case, the inner wire meshes 15, 16, and 17 are butted against each other without overlapping their edges, or are slightly separated from each other, and only the outer wire mesh 18 has its edges overlapped. Figure 5A,
In the examples B and D, the density of the finished material 12 is made as uniform as possible in each direction, and in the example shown in FIG. It is something.

In addition, the core material drawn into a rope shape through a die has stockinette stitches intricately intertwined with each other, but by adjusting the degree of drawing, the density, or softness, of the core material can be adjusted. I can do it. When the density is sufficiently reduced, the core material 6 also becomes a thin cylindrical shape with overlapping edges, as illustrated in FIG.

Also, if you want to make the density of the cushion material different depending on the part, for example, if you want to make the density of part a larger and the density of part b smaller as shown in Fig. 7A, then The purpose can be achieved by press-forming a material formed by gathering the overlaps in one direction.

In the above embodiment, a stainless steel wire mesh is used, but heat-resistant metals such as Inconel, nickel, tungsten, etc. may also be used, and the cross section of the rope-shaped material does not have to be circular, but can be elliptical as appropriate. Needless to say, it can be formed into an L-shape.

C. Effects of the invention 1) There is no manual process like conventional sock wrapping, and most of the processes are mechanized and the structure is suitable for automatic operation, so it can be manufactured efficiently and provides a low-cost product. It is possible.

2) Only a few stockinette knitting machines and a simple drawing machine are required.

3) Since the long rope-shaped material 12 is cut into a ring shape, rings with different diameters can be easily made. In conventional stockinette-knitted material tubes rolled into socks, the diameter of the ring is fixed, and changing the diameter requires changing the kettle of the stockinette-knitting machine, making it extremely difficult to change the diameter.

4) If the wire mesh that is applied vertically to the core material has an overlapping part, by selecting the position of this overlapping part, the density can be adjusted in each part without using a cushion material with a uniform density or a complicated mold. Different cushion materials can be obtained.

5) The thickness of the material 12 can be arbitrarily selected depending on the number of wire meshes to be attached vertically to the core material.

6) The wire mesh that is attached vertically to the core material is woven into a cylindrical shape and folded flat, so the cut end of the wire will not protrude and cause injury to the worker.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an example of a catalytic converter, and FIG. 2 and the following show embodiments of the present invention.
The figure is a side view illustrating the process of manufacturing the cushion material, Figure 3 is a side view showing the material cut to a predetermined length and bent into an annular shape, and Figure 4 is the joining part of the material bent into an annular shape. 5A to 5D are cross-sectional views of the material schematically showing four examples of the structure of the material in which a wire mesh is wrapped around the core material, and FIG. 6 is the density of the core material. FIG. 7A is a cross-sectional view of a cushion material with different densities depending on the part, and FIG. 7B is a cross-sectional view showing how wire mesh is layered when making this material. 1: converter case, 1a: step, 2: inlet, 3: outlet, 4: cushion material, 5: catalyst carrier, 6: core material, 7: wire mesh, 8: die, 9: intermediate material, 10: wire mesh, 11: Dice, 12: Material,
13: Joining part, 14: Short tube.

Claims (1)

[Scope of Claims] 1. An annular cushion material having a cross-sectional shape that matches the corners of a honeycomb catalyst carrier and holds it within a casing, which is made of stockinette knitted heat-resistant and elastic thin wire. A cushion material for a catalytic converter, in which a wire mesh made by folding a stockinette-knitted material cylinder similar to the above and flattened is attached vertically to the outside of a core material made of a rope-shaped cylinder, wrapping the core material. 2. On the outside of the core material, which is formed by squeezing a long material cylinder made of heat-resistant and elastic thin wire stockinette-knitted into a rope shape, a long material is made by knitting the same thin wire into a tube shape and folding it flat. One or more layers of wire mesh are laid out vertically and squeezed to form a long rope-like material, which is then cut to the required length and formed into a ring shape to hold the corners of the honeycomb catalyst carrier inside the casing. A method for manufacturing a cushion material for a catalytic converter, which is press-formed into a cross-sectional shape.