JPH0747928B2 - Catalytic converter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention purifies exhaust gas by oxidizing or reducing harmful components such as carbon monoxide, hydrocarbons and nitrogen oxides discharged from an automobile engine. , To a catalytic converter for obtaining a low pollution engine.

[Prior Art] As a catalyst for obtaining a low-pollution engine by oxidizing or reducing harmful components such as carbon monoxide, hydrocarbons, and nitrogen oxides emitted from automobile engines to obtain a low-pollution engine, high temperature characteristics It is said that the ceramic honeycomb monolith catalyst which is excellent in the above is suitable.

By the way, since the ceramic has a brittle property with poor toughness, it is not damaged by mechanical shock such as vibration generated when the automobile is running.
A holding material having a cushioning property is wound and mounted inside a metal casing.

Since the ceramic honeycomb monolith catalyst is exposed to high-temperature exhaust gas by the operation of the engine, the holding material is naturally required to have excellent heat resistance, that is, a condition that the high temperature and altitude do not decrease. Furthermore, even if the engine is continuously operated and the temperature of exhaust gas gradually rises, it is required that the holding power and cushioning property with respect to the ceramic honeycomb monolith catalyst do not decrease in each temperature range.

As a monolith catalyst holding material capable of satisfying such conditions, there has been conventionally known a material obtained by press-molding a tubular woven structure such as a metal wire knitted or tubular weave.
Therefore, the conventional catalytic converter has a structure in which the ceramic honeycomb structure is mounted with the holding body interposed between the outer peripheral surface of the ceramic honeycomb structure and the inner peripheral surface of the metal casing.

[Problems to be Solved by the Invention] However, in the conventional holding body, although weaving of a large number of metal wires must be performed mechanically, for example, knitting, the weaving of the metal wires must be performed at high speed. Because you can't
Since the weaving work takes time and the manufacturing workability is inferior, there is a problem that the cost is increased.

In addition, since the tubular weaving structure is knitted or woven at a large number of points and the metal wires are restrained at each knitting point or weaving point, it can be said that the tubular weaving structure has a relatively small degree of freedom. Therefore, even if such a woven structure is pressed to form a holder, it can be said that the flexibility and the restoring property are small and the cushioning property is poor. Therefore, there is a drawback that mechanical impact such as vibration generated when the automobile is running cannot be effectively alleviated and absorbed, and the ceramic honeycomb structure may be damaged.

Further, the cushioning property of the holding body is increased only in a specific direction depending on the knitting direction or the weaving direction, and high cushioning properties cannot be obtained in various directions. Therefore, depending on the load direction such as impact, it cannot be effectively relaxed and absorbed, and the ceramic honeycomb structure is adversely affected.

Therefore, as a means for imparting excellent cushioning properties to the holding body, the woven structure before pressure molding may be subjected to corrugation processing or molding into a corrugated shape. By adopting such means, the manufacturing workability is further lowered and the cost is increased.

The present invention has been made in view of such circumstances, and it is possible to realize excellent cushioning property while ensuring excellent flexibility and restoring property, and yet to exhibit the high cushioning property in various directions. An object of the present invention is to provide a catalytic converter in which a ceramic honeycomb structure is held by a holding body, and the manufacturing workability of the holding body is improved to achieve cost reduction.

[Means for Solving the Problems] In order to achieve the above-mentioned object, a first invention according to the present invention is to wind a metal filamentous body formed into a flat shape and curled in a longitudinal direction a large number of times. A holder for pressing the formed ring-shaped material is interposed between the outer peripheral surface of the ceramic honeycomb structure and the inner peripheral surface of the metal casing to hold the ceramic honeycomb structure.

In addition, in order to achieve the above-mentioned object, the second aspect of the present invention
Of the invention is a holder in which a woven structure of a metal wire is attached to at least the inner peripheral surface of a ring-shaped material formed by winding a metal wire filament that is flat and curled in the longitudinal direction many times. However, the ceramic honeycomb structure is held by being interposed between the outer peripheral surface of the ceramic honeycomb structure and the inner peripheral surface of the metal casing.

The woven structure means a braided structure, a knitted structure, a tubular woven structure, or the like.

[Operation] According to the first aspect of the present invention, the ring-shaped material is subjected to continuous and high-speed rolling for curving the metal filaments and curling for curling, respectively, and then by winding many times. It can be easily formed.

In addition, since the ring-shaped material is formed by randomly entangling the curled portions of the adjacent filaments, the holder formed by pressurizing this curls has a high cushion with a large amount of compression and restoration. Property is imparted, and high cushioning properties can be exerted in various directions, so that damage to the ceramic honeycomb structure can be reliably prevented.

According to the second aspect of the invention, the ring-shaped material is easily rolled by rolling a number of times to perform a rolling process for flatly forming the metal filaments and a curling process for curling, and then winding them many times. Can be formed into

In addition, since the ring-shaped material is formed by randomly entangling the curled portions of the adjacent filaments, the amount of compression and the amount of restitution in the holder to which the woven structure of metal wires is attached Since the high cushioning property is imparted and the high cushioning property can be exerted in various directions, it is possible to reliably prevent damage to the ceramic honeycomb structure. Moreover, the workability of assembling the ceramic honeycomb structure is improved due to the smoothness of the metal wire in contact with the ceramic honeycomb structure.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a schematic vertical sectional side view of a catalytic converter according to the first invention, wherein the catalytic converter 1 is clamped by metal bands 6 and divided into upper and lower metal casings 2,2. And a ceramic honeycomb monolith catalyst 3 mounted inside the metal casings 2, 2, that is, a ceramic honeycomb structure 3.

The ceramic honeycomb structure 3 is wound around the outer peripheral surface excluding both axial ends thereof with a heat-expandable sheet 4 containing, for example, untreated unexpanded vermiculite as a main component, and holding members 5 at both axial ends. , 5 are positioned and the heat-resistant expansion sheet 4 and the holders 5, 5 are interposed between the outer peripheral surface of the ceramic honeycomb structure 3 and the inner peripheral surface of the metal casings 2, 2, to thereby form the ceramic honeycomb structure 3 Holding

As shown in FIG. 2A, the holding bodies 5 and 5 are thin linear bodies 5A having a circular cross section made of, for example, a stainless steel wire, and are rolled into a flat tape-shaped continuous body as shown in FIG. 2B. After forming, while applying tension to the flatly formed filament body 5A, by appropriately pressing the corner portion of the member to pull it, and then removing the tension from the filament body 5A, as shown in FIG. 2C, Curl filament 5A naturally curled
To form the curled filamentous body 5A,
The winding shaft 7 is fixed to the outer peripheral surface of the winding shaft 7 shown in FIG. 2D.
By rotating in the direction of the arrow, the curl filament 5A is continuously wound many times, and the curl portion 5a of the curled filament 5A is wound.
Are entangled with each other to form a ring-shaped material 8, the ring-shaped material 8 is pulled out from the winding shaft 7, and then pressure-molded by a die (not shown), as shown in FIG. It is manufactured by deforming the flatly formed filament body 5A in various directions and molding the adjacent filament body 5A and the filament body 5A in an L-shaped cross-section in which they are in close contact with each other.

After pulling out the ring-shaped material 8 from the winding shaft 7 and changing the press-molding die, the holders 5 and 5 having the cross-sectional shape shown in FIG. 4A or 5A can be molded. The holding bodies 5, 5 of the ceramic honeycomb structure 3 and the metal casing are, for example, as shown in FIGS. 4B and 5B.
The ceramic honeycomb structure 3 is held by being interposed between the inner peripheral surfaces 2 and 2.

It is also possible to pull out the ring-shaped material 8 from the winding shaft 7 and then form a holder 5 having a circular cross section as shown in FIG. 6, and use this holder 5 to hold the ceramic honeycomb structure.

[Example 1] A SUS304 metal wire with a diameter of Φ0.15 mm is rolled to a width of 0.5 mm, curled, and then wound around a winding shaft many times, which corresponds to the inner diameter Φ32 mm × Φ48 mm × height 8 mm shown in Fig. 4A. The holding body 5 is formed.

[Example 2] A SUS304 metal wire having a diameter of 0.25 mm was rolled to a width of 0.5 mm, and then a holder 5 corresponding to Fig. 4A in which the inside diameter, the outside diameter and the height were set in the same manner as in [Example 1] above. Molding.

The holding body 5 of [Example 1] and [Example 2], the conventional product 1 (Φ0.1 mm metal wire knit structure) and the conventional product 2 (Φ0.15 mm metal wire knit structure), Table 1 below shows the measurement results of the compression amount and the restoration amount at the same density. However, the pressing load is 50 kg / cm ² , and A = Example 1, B
= Example 2, C = conventional product 1, D = conventional product 2

As is clear from Table 1 above, the filamentous body 5A having a circular cross section is formed into a flat shape, then curled, and the curled material is wound many times to form a ring-shaped material 8, and the ring-shaped material 8 is pressed. The holders of A and B, which are used as holders 5 are C and D.
Compared with the holder of, the compression amount and the restoration amount are both large,
It can be seen that it has a high cushioning property. Therefore, in the catalytic converter 1 which holds the ceramic honeycomb structure 3 with the holder 5 interposed between the outer peripheral surface of the ceramic honeycomb structure 3 and the inner peripheral surfaces of the metal casings 2, 2, a high cushion is provided. Because of the property, mechanical impact such as vibration generated when the automobile is running can be effectively alleviated and absorbed, so that damage to the ceramic honeycomb structure 3 can be reliably prevented. Moreover, since the holding body 5 is formed by press-molding the ring-shaped body 8 formed by randomly entangling the curl portions 5a of the adjacent linear bodies 5A, the above-mentioned high cushioning property is exerted in various directions. Since it is exerted, even if the impact is applied from multiple directions, the ceramic honeycomb structure 3 is protected in various directions with respect to these loading directions.

In addition, the flat filamentous body 5A is wound many times,
After the ring-shaped material 8 is formed, the holder 5 is molded by pressing the ring-shaped material 8 with an appropriate molding die, which eliminates the need for complicated weaving work as in the related art and increases the speed. Since manufacturing can be performed with high efficiency, manufacturing workability is significantly improved and cost reduction can be achieved.

FIG. 7 shows a catalytic converter 1 according to the second invention. In the second invention, the same or corresponding parts as those in the first invention are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 8, the holders 5 and 5 have the weaving structure 9 formed by tubular knitting of metal wires fitted on the winding shaft 7 by external fitting, and then described in the first invention. The base end of the curl filamentous body 5A is fixed to the outer peripheral surface of the weaving structure 9, and the weaving structure 9 is rotated together with the winding shaft 7 in the direction of the arrow so that the curl filamentous body 5A is wound and wound. The curled portions 5a of the curled filamentous body 5A are entangled with each other to form a ring-shaped material 8, and in this state, the ring-shaped material 8 is pulled out from the winding shaft together with the woven structure 9. Then, as shown in FIG. 9, the ring-shaped material 8 is manufactured by covering the entire axially opposite side surfaces, the inner peripheral surface and the outer peripheral surface with the woven structure 9 and applying pressure. That is, the woven structure 9 is attached to the entire surface of the ring-shaped material 8.

With such holders 5, 5, like the first invention,
High cushioning properties are exhibited, and damage to the ceramic honeycomb structure 3 can be reliably prevented, and
The smooth woven structure 9 comes into direct contact with the ceramic honeycomb structure 3 when it is attached to the ceramic honeycomb structure 3, so that the woven structure 9 is prevented from being caught and assembly workability is improved.

Further, as shown in FIG. 10A, a holding body 5 in which a curled filament body 5A is wound around the outer peripheral surface of the woven structure 9 with a uniform thickness.
By manufacturing the above, it is possible to hold the ceramic honeycomb structure 3 like the holder 5 in FIG. 5B.
The weaving structure 3 may be corrugated as shown in FIG. 10B and used as shown in FIG. 5B.

[Effects of the Invention] Since the present invention is configured as described above, the following effects are achieved.

According to the catalytic converter of claim (1), since the ring-shaped material is formed by randomly intertwining the curled portions of the adjacent filaments, the ring-shaped material is applied to the holder formed by pressurizing it. Since it is given a high cushioning property with a large amount of compression and restoration, it can effectively absorb and absorb mechanical shocks such as vibrations generated when the vehicle is running, and reliably prevent damage to the ceramic honeycomb structure. it can. Moreover, since the holding body is a ring-shaped body formed by randomly entangling the curls of the adjacent filaments, the above-mentioned high cushioning property is exerted in various directions. Even if a shock is applied from multiple directions, the ceramic honeycomb structure is protected in various directions in response to these load directions, and damage to the ceramic honeycomb structure is prevented.

In addition, the ring-shaped material can be easily formed by rolling the metal strip into a flat shape and curling the curling continuously and at high speed, and then easily winding it up a number of times. Workability can be improved and price reduction can be achieved.

Further, according to the catalytic converter of claim (2), since the ring-shaped material is formed by randomly entangling the curled portions of the adjacent filaments, the woven structure of the metal wire is attached. The thus-obtained holder is provided with high cushioning properties with a large amount of compression and restoration, and high cushioning properties can be exerted in various directions, so that damage to the ceramic honeycomb structure can be reliably prevented. Moreover, the workability of assembling the ceramic honeycomb structure is improved due to the smoothness of the metal wire in contact with the ceramic honeycomb structure.

Further, the ring-shaped material can be easily formed by rolling the metal filaments into a flat shape and performing the curling for curling, respectively, continuously and at high speed, and then easily winding them up many times. Manufacturing workability can be improved and price reduction can be achieved.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional side view showing an embodiment of the first invention,
2A to 2D are process diagrams for forming a ring-shaped material, FIG. 3 is a vertical sectional side view showing an example of a holding body, FIG. 4A is a vertical sectional side view showing another example of a holding body, and FIG. Fig. 4A is a schematic vertical side view of a catalytic converter having a holding body, Fig. 5A is a vertical side view showing another example of a holding body, and Fig. 5B is a schematic view of a catalytic converter having a holding body of Fig. 5A. FIG. 6 is a vertical sectional side view showing still another example of the holding body, FIG. 7 is a schematic vertical sectional side view showing one embodiment of the second invention, and FIG. 8 is a molding step diagram of the holding body. , FIG. 9 is a vertical sectional side view showing an example of a holding body, and FIG.
FIG. A is a vertical sectional side view showing another example of the holding body, and FIG. 10B is a vertical sectional side view showing still another example of the holding body. 1 …… Catalytic converter 2,2 …… Metal casing 3 …… Ceramic honeycomb structure 5,5 …… Holder 5A …… Linear body 5a …… Curl part 8 …… Ring material

Claims (2)

[Claims] 1. A catalytic converter comprising a metal casing and a ceramic honeycomb structure mounted inside the metal casing, wherein a plurality of metal filaments formed flat and curled in the longitudinal direction are provided. A holding body formed by processing a ring-shaped material formed by winding is held between the outer peripheral surface of the ceramic honeycomb structure and the inner peripheral surface of the metal casing to hold the ceramic honeycomb structure. Catalytic converter to. 2. A catalytic converter comprising a metal casing and a ceramic honeycomb structure mounted inside the metal casing, wherein a plurality of metal filaments formed flat and curled in the longitudinal direction are provided. A holding body in which a woven structure of metal wires is attached to at least the inner peripheral surface of the ring-shaped material formed by winding is interposed between the outer peripheral surface of the ceramic honeycomb structure and the inner peripheral surface of the metal casing. A catalytic converter characterized by holding a ceramic honeycomb structure.