JPH0422152Y2 - - 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 for parts that are exposed to high temperatures during use, such as 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. ing.

These parts such as silencers and catalytic converters are
These parts are manufactured separately from the exhaust pipe and are later assembled and connected to the exhaust pipe, but the connections between these parts and the exhaust pipe must be constructed airtight to prevent exhaust gas from leaking. There is.

For this reason, the connection between the exhaust pipe and the catalytic converter has conventionally been configured as shown in FIG. 5.

That is, both the first and second pipes 1 to be connected to each other,
A first flange 3 is fixed to the outer peripheral surface of the end of the first tube 1 of the tubes 2, and a second flange 4 is fixed to the outer peripheral surface of the end of the second tube 2. A sealing material 6 is fitted into a closed annular groove 5 formed on the surface of the first flange 3 facing the second flange 4 with a portion protruding from the groove 5. align both the first and second flanges 3 and 4 with each other,
By screwing nuts (not shown) into bolts (not shown) inserted through the through holes 7 drilled in the first flange 3 and the through holes 8 drilled in the second flange 4, and further tightening. First and second flanges 3, 4
The first and second pipes 1 and 2 are joined to each other in a state where they are kept airtight.

Since the above-mentioned pipe connection section becomes high in temperature due to exhaust heat during use, the sealing material 6 used in this pipe connection section needs to be heat resistant. Therefore, as the sealing material 6 to be incorporated into such a part, a material having a structure as shown in FIGS. 6 and 7 is used, as described in, for example, Japanese Utility Model Application No. 53-101962.

Among these, the one shown in FIG. 6 is one in which a heat-resistant filler 10 with a core material 9 buried therein is stacked in multiple layers, and the periphery is covered with a thin metal plate 11, and the one shown in FIG. 7 is simply heat-resistant filler 10 and thin metal plate 1
1.

The sealing material 6 shown in FIGS. 6 and 7 has a shape as shown by the two-dot chain line in each figure when not in use.
4, and make it into the shape shown by the solid line in each figure.

(Problems to be Solved by the Invention) However, in the pipe connection section using the conventional flange, which incorporates the sealing material 6 as described above, it is necessary to improve the following problems.

First, as a first problem, it is necessary to improve the compression resistance of the sealing material 6 to ensure sealing performance. As a second problem, it is necessary to make it easy to extract the crushed sealing material 6 from inside the groove 5.

That is, when the sealing material 6 is strongly held between the first and second flanges 3 and 4, the sealing material 6 is crushed so that its cross section becomes flat, and the width of the cross section increases. Unless the width of the sealing material 6 is prevented from increasing by some means, the sealing material 6 will be compressed with a relatively weak force and its thickness will become small. When the sealing material 6 is compressed with a light force, the contact pressure between the sealing material 6 and both the first and second flanges 3 and 4 becomes small, and airtightness between the two flanges 3 and 4 is insufficient. becomes.

Therefore, in the example shown in FIG. 7, the width of the cross section of the sealing material 6 is widened, and the inner surface 5a near the outer periphery and the inner surface 5b near the inner periphery of the groove 5 in which the sealing material 6 is fitted are widened. This is being prevented.

However, since the sealing material 6 has heat resistance but poor elasticity and plasticity, when crushed between the first and second flanges 3 and 4, both flanges 3 and 4 Even after separating them, they remain crushed.

Therefore, as shown in FIG. 7, the sealing material 6 is crushed by the first and second flanges 3, 4, and both the inner and outer circumferential surfaces of the sealing material 6 and both the inner and outer surfaces 5b of the groove 5, 5a, it becomes troublesome to remove the old sealing material 6 from the groove 5 when it becomes necessary to replace the sealing material 6.

As shown in FIG. 6, in the case of the sealing material 6 in which the core material 9 is embedded in the heat-resistant filler 10, the sealing material 6
Although the rigidity is high, if both the inner and outer circumferential surfaces of the sealing material 6 and the inner and outer surfaces 5b and 5a of the groove 5 are not brought into close contact, a practically sufficient sealing performance cannot be exhibited.

The pipe connection part using the flange of the present invention can be constructed as described above by devising the relationship between the size of the sealing material 6 and the size of the groove 5 formed in the flange 3 to fit the sealing material 6. This eliminates all of these inconveniences.

(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. Fixed first flange 3
Bolts and nuts inserted through the plurality of through holes 7 formed in the second tube 2 and the plurality of through holes 8 formed in the second flange 4 fixed to the outer peripheral surface of the end of the second pipe 2 are screwed together and further tightened. By doing so, both the first and second flanges 3 and 4 are joined.

The airtightness between the mutually opposing surfaces of the two flanges 3 and 4 is formed on the side surface of the first flange 3 that faces the second flange 4, surrounding the entire circumference of the first pipe 1. It is held by a sealing material 6 fitted into the closed annular groove 5. Although this sealing material 6 has heat resistance, it has poor elasticity,
Use something that has plasticity.

In particular, in the pipe connection using the flange of the present invention, as shown in FIG. The size is such that the outer circumferential surface of the sealing material 6 comes into close contact with the outer circumferential inner surface 5a of the groove 5 in the state in which the sealing material 6 is held in place.

Further, the inner diameter of the sealing material 6 is made sufficiently larger than the inner diameter of the groove 5, and when the sealing material 6 is sandwiched between the first and second flanges 3 and 4, the inner diameter of the sealing material 6 is The circumference and the inner surface 5b of the groove 5 near the inner circumference
A gap 12 is formed between the two.

In order to bring the outer peripheral surface of the sealing material 6 into close contact with the inner surface 5b near the outer periphery of the groove 5, with the sealing material 6 sandwiched between the first and second flanges 3 and 4 as described above, For example, the thickness of the sealing material 6 (outer diameter of the cross section) is 4 mm, and the depth of the groove 5 is 2.8 mm (although it varies depending on conditions such as the size of the sealing material 6 used and the depth of the groove 5). mm, the outer diameter d of the sealing material 6 when not in use is 0.3 mm smaller than the outer diameter D of the groove 5.
It is larger than a value that is slightly smaller, and smaller than a value that is about 0.5 mm larger than the outer diameter D of the groove 5 (D + 0.5
mm≧d≧D−0.3mm).

(Function) The function of the pipe connection using the flange of the present invention constructed as described above is similar to that of the conventional pipe connection described above. That is, the first flange 3 fixed to the end of the first pipe 1 and the second flange 4 fixed to the end of the second pipe 2 are connected through the through holes 7 and 8 of both flanges 3 and 4. The bolt and nut inserted in the are screwed together and further tightened to connect them. As a result,
A sealing material 6 fitted into the groove 5 of the first flange 3 is strongly compressed between the flanges 3 and 4, thereby maintaining airtightness between the flanges 3 and 4.

When the sealing material 6 is compressed between the first and second flanges 3 and 4, the width of the cross section of this sealing material 6 increases, but as revealed by the inventor's research, it has poor elasticity. When the closed annular sealing material 6 having plasticity is compressed, the inner diameter of the sealing material 6 is only slightly reduced, and the outer diameter is increased, thereby widening the cross-sectional width as described above.

Therefore, if the relationship between the size of the sealing material 6 and the size of the groove 5 formed in the first flange 3 for fitting this sealing material 6 is determined as described above, this sealing material 6 will be As shown in FIG. 1, its outer periphery contacts the inner surface 5a of the groove 5 closer to the outer periphery, and a gap 12 exists between the inner periphery of the sealing material 6 and the inner surface 5b of the groove 5 closer to the inner periphery. It becomes a state where

In this way, even if the gap 12 exists between the inner periphery of the sealing material 6 and the inner surface 5b of the groove 5 near the inner periphery, the outer periphery of the sealing material 6 is held down by the inner surface 5a of the groove 5 near the outer periphery. It is clear from experiments conducted by the inventor that the sealing material 6 will not be compressed by a light force as long as the pressure is on.

That is, the present inventor incorporated the pipe connection part of the present invention incorporating the sealing material 6 having the size as shown in FIG. 1, and the sealing material 6 having the size as shown in FIGS. 6 and 7. When the relationship between the compressive load and the amount of compression of the sealing material 6 in a conventional pipe connection was measured, the results shown in FIGS. 3 and 4 were obtained.

When conducting this experiment, the sealing material 6 was one in which a heat-resistant filler 10 made of expanded graphite particles was surrounded by a thin metal plate 11 made of stainless steel and having a thickness of 0.2 mm, as shown in FIG. It was used. Seal material 6
The diameter of the cross section was 4 mm, the inner diameter of the sealing material 6 was 50 mm, and the sealing material 6 was fitted into the groove 5 with a depth of 2.8 mm.

The solid line a shown in FIGS. 3 and 4 indicates the amount of compression of the sealing material 6 incorporated in the pipe connection part of the present invention in relation to the compression load, and the broken line b in FIG.
As shown in FIG. 6, the amount of compression of the sealing material 6 when there is a gap between the inner and outer circumferences of the sealing material 6 and the inner and outer surfaces 5b and 5a of the groove 5 is expressed as the compression load. This is shown in relation to As is clear from FIG. 3, in the case of the present invention, the pressing force of the sealing material 6 can be sufficiently increased compared to the structure shown in FIG. 6.

Furthermore, as shown in FIG. 7, the broken line b in FIG.
The amount of compression of the sealing material 6 when suppressed by b and 5a is shown in relation to the compression load. As is clear from FIG. 4, in the case of the present invention, despite the existence of the gap 12 on the inner circumferential side of the sealing material 6, the pressing force is approximately the same as when both the inner and outer circumferences of the sealing material 6 are suppressed. You can get it.

(Effects of the invention) The pipe connection part using the flange of the invention is constructed and functions as described above, but even when a sealing material that has poor elasticity and plasticity instead of heat resistance is used, The load required to compress this sealing material is large, and when the sealing material is compressed between both the first and second flanges, the pressing force of the sealing material becomes large, and the airtightness between the two flanges is increased. You can improve your performance.

Also, since there is a gap between the inner periphery of the sealing material and the inner surface of the groove, when replacing the sealing material, insert a screwdriver into this gap to remove the old sealing material from the inside of the groove. You can easily take it out.

[Brief explanation of the drawing]

Fig. 1 is an enlarged cross-sectional view of part A in Fig. 5, showing the relationship between the sealing material and the groove constituting the pipe connection part of the present invention, and Fig. 2 shows the cross-sectional shape of the sealing material when it is not in use. A partial cross-sectional view, Figures 3 and 4 are diagrams comparing the performance of the sealing material of the present invention and a conventional sealing material for pipe connections, and Figure 5 is a diagram comparing the performance of the sealing material of the present invention and that of a conventional sealing material for pipe connections. FIGS. 6 and 7 are enlarged sectional views of section A in FIG. 5, showing two examples of the relationship between the sealing material and the groove constituting the conventional pipe connection. DESCRIPTION OF SYMBOLS 1...First pipe, 2...Second pipe, 3...First flange, 4...Second flange, 5...Concave groove, 5a...Inner surface near outer periphery, 5b...Inner side Circumferential inner surface, 6...Sealing material, 7, 8...Through hole, 9...
... core material, 10 ... heat-resistant filler, 11 ... thin metal plate, 12 ... gap.

Claims (1)

[Scope of utility model registration request] A plurality of through holes formed in a first flange fixed to the outer peripheral surface of the end of the first pipe, and a plurality of through holes formed in a second flange fixed to the outer peripheral surface of the end of the second pipe. By screwing the inserted bolt and nut together and tightening them further, both the first and second flanges are joined,
A closed annular concave groove formed on the side surface of the first flange, on the surface facing the second flange, surrounding the entire circumference of the first pipe, to provide airtightness between the opposing surfaces of both flanges. In pipe connections using flanges, which are held by a sealing material fitted to The outer diameter of the sealing material is set to such a size that the outer circumferential surface of the sealing material comes into close contact with the inner surface of the groove near the outer periphery when the sealing material is held between the first and second flanges, and Inner diameter, first,
The flange is characterized in that the size is such that a gap is formed between the inner periphery of the sealing material and the inner surface of the groove near the inner periphery when the second flange is held between the two flanges. Pipe connection used.