JPH0241432Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The pipe connection using the flange according to this invention is
It is used when connecting the end of an exhaust pipe for discharging the exhaust gas from an automobile engine into the atmosphere and a catalytic converter installed in the middle of this exhaust pipe.

(Prior Art) For example, when exhaust gas emitted from an automobile engine is dissipated into the atmosphere, it is discharged through a long exhaust pipe whose one end is connected to the exhaust manifold of the engine.

By the way, a muffler or a catalytic converter is installed in the middle of such an exhaust pipe to attenuate the noise components contained in the exhaust, or to detoxify the harmful components contained in the exhaust. It is.

These parts such as silencers and catalytic converters are
Parts manufactured separately from the exhaust pipe are later assembled and connected in the middle of the exhaust pipe, but the connection between these parts and the exhaust pipe must be constructed airtight to prevent exhaust gas from leaking.

For this reason, the connection between the exhaust pipe and the catalytic converter has conventionally been configured as shown in FIG. 3.

That is, both the first and second pipes 1 to be connected to each other,
2, a first flange 3 is fixed to the outer circumferential surface of the end of the first tube 1, and a second flange 4 is fixed to the outer circumferential surface of the end of the second tube 2. A sealing material 6 is provided in a closed annular groove 5 formed on one side of the first flange 3 in a portion facing the second flange 4.
is fitted into the groove 5 with a part protruding from the groove 5, and in this state both the first and second flanges 3, 4
are aligned with each other, and a nut (not shown) is screwed onto a bolt (not shown) inserted through a circular hole 7 drilled in the first flange 3 and a circular hole 8 bored in the second flange 4. By tightening, both the first and second flanges are joined, and both the first and second pipes 1 and 2 are joined to each other while maintaining airtightness.

(Problems to be Solved by the Invention) However, in the pipe connection section using the conventional flange configured as described above, the following disadvantages occur.

That is, in order to fit the sealing material 6 inside, the work of forming the groove 5 on the side surface of the first flange 3 and the surface processing of the second flange 4 are troublesome, and the It is inevitable that the manufacturing cost will increase and the cost of the entire connection will increase.

Utility Model Publications No. 59-40686 and No. 50-83415 describe a structure in which the exhaust pipe joint is kept airtight by using a flange that is relatively easy to work with, but it is not durable. It cannot be said that it is necessarily sufficient in terms of sex and airtightness.

First, in the case of the device described in Japanese Utility Model Application Publication No. 59-40686, two pipes are used to prevent problems such as cracks caused by engine vibrations being transmitted to the rear pipes. The sealing material is in sliding contact with the opposing flange surfaces. For this reason, the surface of the sealing material is required to have a low coefficient of friction, and it cannot necessarily ensure sufficient heat resistance, so it cannot be used in areas that require a high degree of heat resistance, such as the connections of catalytic converters. occurs.

In addition, in the case of the device described in Japanese Utility Model Application Publication No. 50-83415, a sealing material is held in the gap between the curved parts formed on the inner peripheral edge of a flange formed by press-forming a metal plate. In particular, no consideration has been given to sealing materials. Moreover, since the flange is made by press-forming a metal plate and does not necessarily have sufficient rigidity, the sealing material may not be sufficiently deformed due to the pressure exerted by the flange. Therefore, if the usage conditions are severe, sufficient airtightness and durability may not be obtained.

In addition, in the case of a structure in which a sheet-shaped sealing material is simply held between flat flange surfaces, it is difficult to obtain sufficient airtightness because minute irregularities on the flange surfaces greatly affect airtightness.

On the other hand, Japanese Utility Model Application Publication No. 60-71764 discloses an idea regarding a sealing material which is formed into a closed annular shape by winding stainless wool with a thin metal plate such as copper or stainless steel. As described above, the sealing material in which the stainless steel wool is surrounded by a thin metal plate has sufficient heat resistance and therefore has sufficient durability as it is, but there remains a problem in terms of airtightness.

That is, in order to obtain sufficient airtightness by sandwiching the sealing material between a pair of flanges, it is necessary for the sealing material to be deformed to a certain extent, but this is described in the above publication. Similarly, in the case of a sealing material made of stainless wool wrapped around a thin metal plate, the rigidity is too high and it is difficult to deform, so that sufficient airtightness may not always be obtained.

In order to ensure sufficient airtightness and to make the sealing material deformable to some extent, expanded graphite can be used instead of stainless wool as the member wrapped around the thin metal plate, but it is better to use expanded graphite instead of stainless wool. Simply replacing it with expanded graphite causes problems in terms of durability.

In other words, when expanded graphite is included in a sealing material installed in a high-temperature part such as the connection part of a catalytic converter, in order to prevent the expanded graphite from burning, it is necessary to Care must be taken to prevent air from entering.

However, in the case of the device described in the above-mentioned Japanese Utility Model Publication No. 60-71764, the above considerations were not taken into account, and if expanded graphite was simply used instead of stainless wool, the durability would be reduced due to combustion of the expanded graphite. sexuality is severely impaired.

The pipe connection section using the flange of the present invention eliminates all of the above-mentioned disadvantages.

(Means for Solving the Problems) The pipe connection part using the flange of the present invention is similar to the conventional pipe connection part described above, as shown in FIG. Of the tubes 1 and 2, a first flange 3 is fixed to the outer circumferential surface of the end of the first tube 1, and a second flange 4 is fixed to the outer circumferential surface of the end of the second tube 2.

In this way, the first flange 3 fixed to the outer circumferential surface of the end of the first tube 1 and the second flange 4 fixed to the outer circumferential surface of the second tube 2 are aligned with each other and bolted together. The first and second pipes 1 and 2 are kept airtight by a sealing material 6 which is joined by a nut and is clamped between the first and second flanges 3 and 4.

Furthermore, in the pipe connection section using the flange of the present invention, the end 2a of the second pipe 2 is fixed to the outer peripheral surface of the end of the second pipe 2 with a second flange 4.
It's made to stand out a little more. In this way, the end 2 of the second pipe 2 protrudes beyond the second flange 4.
A ring-shaped sealing material 6 is fitted onto the outside of the hole a.

As shown in FIG. 2, this sealing material 6 is constructed into a closed ring shape by winding a refractory material 10 whose main component is expanded graphite particles with a thin metal plate 11 made of stainless steel or the like. The outer diameter of the first tube 1 is the same or slightly larger (for example, 0.5 mm maximum).
degree) has a large inner diameter so that the outer peripheral surface of the end 2a and the inner peripheral surface of the sealing material 6 can be easily fitted onto the end 2a of the second pipe 2. This is done so that there is not a large gap between the two.

Both end edges of the thin metal plate 11 around which the refractory material 10 is wound are overlapped with each other to form an overlapping part 12. However, when the sealing material 6 is fitted onto the end 2a of the second pipe 2, , this overlapping portion 12 faces an inclined surface 9 of a first flange 3, which will be described later.

On the other hand, the first flange 3 fixed to the end of the first tube 1 partially protrudes beyond the edge of the first tube 1. At the inner peripheral edge of the opening of the first flange 3, a protruding portion located on the opposite side from the first pipe 1 is formed with a mortar-shaped inclined surface 9 that aligns with the sealing material 6. The inclination angle θ of this inclined surface 9 is determined in the range of 30 to 60 degrees, but preferably
The temperature should be 45-60 degrees.

The closed annular sealing material 6 described above has the overlapping portion 12 of the end edges of the thin metal plate 11, which encloses the refractory material 10 mainly composed of expanded graphite, facing the inclined surface 9 of the first flange 3. In this state, it is fitted onto the end portion 2a of the second tube 2, but the seam 13 of the overlapping portion 12 is directed toward the outer periphery of the sealing material 6.

(Function) The pipe connection part using the flanges of the present invention is constructed as described above, but both the first and second flanges are fixed to the ends of the first and second pipes 1 and 2. When the bolts and nuts (both not shown) inserted into the circular holes 7 and 8 bored in the pipes 3 and 4 are tightened, the sealing material 6 fitted onto the end 2a of the second pipe 2 is pushed downward to the right in FIGS. 1 and 2 by the inclined surface 9 of the flange 3 of FIG. and the outer peripheral surface of the end 2a of the tube 2 are in close contact with each other.

At this time, since the overlapping portion 12 of the thin metal plates 11 constituting the sealing material 6 receives force from the inclined surface of the first flange 3 in the direction of tightening the thin metal sheets 11, this overlapping portion 12 The opening of the opening is tightly closed, and the refractory material 10 inside does not spill out when the opening opens, and air does not enter inside the thin metal plate 11. Therefore, when the expanded graphite is heated at high temperatures, The refractory material 10, which is the main component, does not burn.

(Effects of the invention) Since the pipe connection part using the flange of the invention is configured and operates as described above, there is no need to perform troublesome processing on the flange, and the connection part can be manufactured at low cost. , can have both sufficient airtightness and durability (including heat resistance), and can ensure sufficient reliability even under severe usage conditions such as the connection part of a catalytic converter.

In particular, in the case of the present invention, as the pipe connections are assembled, force is applied to the thin metal plates that make up the sealing material in the direction of retightening, so it is possible to reliably prevent the overlapping portions of these thin metal plates from opening. , a higher degree of reliability can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a half longitudinal sectional view showing a pipe connection using the flange of the present invention, Fig. 2 is an enlarged view of part A in Fig. 1, and Fig. 3 is a pipe connection using a conventional flange. It is a half longitudinal cross-sectional view. 1...First pipe, 2...Second pipe, 3...First flange, 4...Second flange, 5...Groove,
6... Sealing material, 7, 8... Circular hole, 9... Inclined surface, 10... Fireproof material, 11... Metal thin plate, 12...
...overlapping part, 13... seam.

Claims (1)

[Scope of utility model registration request] A first flange fixed to the outer peripheral surface of the end of the first pipe and a second flange fixed to the outer peripheral surface of the second pipe are aligned with each other and joined by bolts and nuts, In a pipe connection using a flange, the end of the second pipe maintains airtightness between the first and second pipes by a sealing material held between the second flanges. By projecting a little more than the second flange, the end of this second pipe is made into a protruding part, and a part of the end of the second pipe is made to protrude slightly beyond the edge of the first pipe. At the inner peripheral edge of the first flange fixed in a protruding state, a mortar-shaped inclined surface that matches the sealing material is formed on the opposite side of the first pipe, and expanded graphite is formed on the protruding part. It is made by winding a refractory material whose main component is a thin metal plate.
A closed annular sealing material having an inner diameter that is the same as or slightly larger than the outer diameter of the second pipe is placed so that the overlapping portion of the thin metal plates faces the inclined surface of the first flange. , and a pipe connection part using a flange, characterized in that the overlapping part is fitted onto the sealing material with the seam facing toward the outer periphery of the sealing material.