JPH0429182Y2 - - Google Patents

Description

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

(Prior Art) For example, when exhaust gas discharged 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 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, as shown in Japanese Utility Model Application Publication No. 53-101962, the connecting portion between the exhaust pipe and the catalytic converter has conventionally been configured as shown in FIG. 7.

That is, both the first and second pipes 1 to be connected to each other,
A first flange 3 is fixed to the outer circumferential surface of the end of the first tube 1 of the tubes 2, 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 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 the first and second flanges 3 and 4 with each other, and insert bolts (not shown) through the circular holes 7 drilled in the first flange 3 and the circular holes 8 drilled in the second flange 4. ) by screwing a nut (not shown) and further tightening, both the first and second flanges 3 and 4 are joined, and both the first and second pipes 1 and 2 are kept airtight. are joined to each other.

However, in the pipe connection section using the conventional flange constructed 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 first and second flanges 3, 4 are It is inevitable that the production cost will increase and the cost of the connection part as a whole will increase.

In order to eliminate such inconvenience, airtightness is maintained between the first and second flanges 3 and 4 that connect the first and second pipes 1 and 2 by a structure as shown in Fig. 2. It is being considered that

That is, a part of the first flange 3 fixed to the end of the first tube 1 is made to protrude beyond the edge of the first tube 1, and the inner peripheral edge of the first flange 3 is connected to the first flange 3. An inclined surface 9 having a mortar shape and aligned with the sealing material 6 is provided at the opening of the protruding portion located on the opposite side of the first tube 1.
is formed. Moreover, the end 2a of the second tube 2 is
A sealing material 6 is fitted onto the projecting end 2a so as to project slightly beyond the second flange 4 fixed to the outer circumferential surface of the end of the second pipe 2. As shown in FIG. 3, this sealing material 6 is made by winding a fireproof material 10 such as carbon or asbestos with a metal plate 11 such as a stainless steel plate.

When connecting both the first and second pipes to each other using such an improved pipe connection part, the circular holes 7a and 7b drilled in the first flange 3 and the circular holes 7a and 7b drilled in the second flange 4 are used. With the circular holes 8a, 8b aligned with each other, a bolt is inserted into each circular hole 7a, 8a, 7b, 8b, and the bolt and nut (not shown) are screwed together and further tightened.

Through this screwing and tightening work, the distance between the first and second flanges 3 and 4 is narrowed, and the sealing material 6 fitted onto the end 2a of the second pipe 2 is attached to the inclined surface of the first flange 3. 9 and the second flange 4, the outer diameter is elastically contracted, and the inner circumferential surface of this sealing material 6 and the outer circumferential surface of the end 2a of the second pipe 2 come into close contact. .

(Problems to be Solved by the Invention) However, even with the improved pipe connection constructed and operated as described above, the following disadvantages still occur.

That is, both the first and second flanges 3, 4 have circular holes 7a, 7b, 8a, 8b at both end positions, respectively.
These circular holes 7a, 7b, 8
A plurality of bolts and nuts inserted through holes a and 8b are screwed together and further tightened.

This screwing and tightening work is performed on one of the circular holes 7a and 8a.
The problem can be solved if the bolts inserted through the holes 7b and 8b are tightened evenly, and both the first and second flanges 3 and 4 are held parallel to each other during the tightening work. Although this does not occur, in automobile assembly factories, from the standpoint of work efficiency, threading and tightening of multiple bolts is not always done evenly, and the bolts and nuts inserted into one of the circular holes 7a and 8a are In some cases, the bolt and nut inserted into the other circular holes 7b and 8b are screwed together and the bolt and nut are completely tightened before the screwing and tightening is performed at all.

In this way, the bolts and nuts inserted separately into the circular holes 7a, 8a, 7b, 8b drilled at opposite positions of the first and second flanges 3, 4 are unevenly tightened. In this case, when one bolt and nut are first screwed together and tightened, both the first and second flanges 3 and 4 become non-parallel to each other as shown in FIG. , 4 moves in the direction where the distance between the flanges 3 and 4 becomes wider, and a part of the sealing material 6 protrudes from the inclined surface 9.

A portion of the sealing material 6 protruding from the inclined surface 9 is
When the remaining bolts (inserted through the circular holes 7a and 8a) and nuts are screwed together and tightened, the bolts are strongly pinched between the first and second flanges 3 and 4, as shown in FIG. As shown in detail in FIG. 6, the outer peripheral edge is crushed.

If the outer peripheral edge of the sealing material is extremely crushed in this way, the thin metal plate 11 constituting the sealing material 6 during use.
This is not preferable because it not only causes cracks to occur, but also causes non-uniform contact between the flanges 3 and 4 and the sealing material 6, resulting in a decrease in sealing performance.

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

b. Structure of the invention (means for solving the problem) The pipe connection part using the flange of the invention has a part on the outer peripheral surface of the end of the first pipe that protrudes beyond the edge of the first pipe. Fix the first flange in the
A mortar-shaped inclined surface is formed on the inner peripheral edge of the opening on the opposite side of the first flange from the first pipe, and the second flange is fixed to the outer peripheral surface of the end of the second pipe, and a refractory material A closed annular sealing material formed by winding a thin plate and having an inner diameter that can be freely fitted onto the end of the second pipe protruding from the second flange is aligned with the mortar-shaped inclined surface, By aligning the first flange and the second flange with each other and joining both flanges with bolts and nuts, both the first and second pipes are joined while maintaining airtightness and liquidtightness. In a pipe connection using a flange, a closed annular stepped portion is formed at the outer peripheral edge of the inclined surface, surrounding the entire circumference of the inclined surface and recessed from the side surface of the first flange. It is characterized by

(Function) When the above-mentioned stepped portion in the pipe connection using the flange of the present invention is sandwiched between the first and second flanges, a part of the sealing material is pressed particularly strongly. Prevent it from being crushed.

(Example) Next, the present invention will be explained in more detail while explaining the illustrated embodiment.

The pipe connection part using flanges in this embodiment is similar to the case of the pipe connection part described above, as shown in FIG.
A first flange 3 is fixed to the outer circumferential surface of the end of the first tube 1 of the tubes 2, 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 pipe 1 and the second flange 4 fixed to the outer circumferential surface of the second pipe 2 are aligned with each other and are connected to the bolts. The sealing material 6 held between the first and second flanges 3 and 4 maintains airtightness and liquidtightness between the first and second pipes 1 and 2. I have to.

Further, the end portion 2a of the second tube 2 is made to protrude slightly beyond the second flange 4 fixed to the outer peripheral surface of the end portion of the second tube 2. An annular sealing material 6 is fitted onto the end 2a of the second tube 2 that protrudes beyond the second flange 4 in this manner. This sealing material 6 is made into a closed annular shape by wrapping a refractory material 10 such as expanded graphite particles with a thin metal plate 11 such as stainless steel, as shown in FIG. The outer diameter of the second pipe 1 is the same as that of the second pipe 1, or slightly larger than this (for example, the maximum
It has a large inner diameter (approximately 0.5 mm), and has a large inner diameter so that it can be easily fitted onto the end 2a of the second pipe 2. Make sure that there are no large gaps between the surfaces.

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 circumferential edge of the first flange 3, a protruding portion located on the opposite side of the first pipe 1 has an inclined surface 9 formed in the shape of a mortar and aligned with the sealing material 6. ing.

Furthermore, in the pipe connection part of the present invention, as shown in FIG. 1, the outer peripheral edge portion of the inclined surface 9 is provided with a side surface 3 of the first flange 3, which surrounds the entire circumference of the inclined surface 9.
A closed annular step 12 recessed further than a is formed.

The pipe connection section using the flanges of this embodiment is constructed as described above, but the first and second pipes 1, 2
Both first and second flanges 3, 4 fixed to the ends of
When the bolts and nuts (all not shown) inserted into the circular holes 7a, 7b, 8a, and 8b drilled in the pipes are tightened, the sealing material 6 fitted onto the end 2a of the second pipe 2 is pushed by the inclined surface 9 of the flange 3 and is pressed against the second flange 4, and its outer diameter is elastically contracted, and the inner peripheral surface of this sealing material 6 and the end 2a of the second pipe 2 are Close contact with the outer peripheral surface.

When tightening the bolts and nuts in this manner, the bolts and nuts inserted into the circular holes 7a and 8a bored at one end of both the first and second flanges 3 and 4 are tightened, and the bolts and nuts are tightened at the other end. Do not simultaneously tighten the bolts and nuts inserted through the drilled circular holes 7b and 8b,
When one bolt and nut are tightened first and the flanges 3 and 4 become non-parallel, a part of the sealing material 6 forms an inclined surface 9 on the first flange 3.
The protrusion outside the pipe is the same as in the case of the pipe connection described above. However, in the case of a pipe connection using the flange of the present invention, when the next remaining bolt and nut are tightened, the protruding portion of the sealing material will cause a step 12 formed on the side surface of the first flange 3.
and the side surface of the second flange 4, so that this protruding portion is strongly pinched between the first and second flanges 3, 4. It disappears.

Therefore, even if the bolts and nuts inserted through the circular holes 7a, 8a, 7b, and 8b at both ends of the first and second flanges 3 and 4 are not evenly tightened, A part of the sealing material sandwiched between the flanges 3 and 4 is prevented from being strongly crushed.

c. Effects of the invention Since the pipe connection part using the flange of the present invention is constructed and operates as detailed above, there is no need to perform troublesome processing on the flange, and the connection part can be manufactured at low cost. Even if the bolts and nuts on both ends of the flange are not tightened evenly when assembling the pipe connection part, a part of the seal material will not be crushed strongly, which will reduce the durability of the seal material. This eliminates the possibility of causing damage or deteriorating the sealing performance.

[Brief explanation of drawings]

Figure 1 is an enlarged sectional view corresponding to part A in Figure 2, showing a pipe connection using the flange of the present invention;
The figure is a longitudinal sectional view of a pipe connection that is the subject of the present invention, Figure 3 is a partially enlarged sectional view of the sealing material used in this connection, and Figure 4 shows a state in which the bolt and nut are tightened unevenly. FIG. 5 is a view corresponding to the left half of FIG. 2 showing a state in which a part of the sealing material is strongly held between the first and second flanges, and FIG. The figures are an enlarged cross-sectional view of part B of Fig. 5 showing the sealing material deformed by being strongly pinched, and
The figure is a half longitudinal sectional view showing a pipe connection using a conventional flange. DESCRIPTION OF SYMBOLS 1...First pipe, 2...Second pipe, 2a...End, 3...First flange, 3a...Side surface, 4...
... second flange, 5 ... groove, 6 ... sealing material,
7, 7a, 7b, 8, 8a, 8b... circular hole, 9...
... Sloped surface, 10 ... Fireproof material, 11 ... Metal thin plate,
12...Danbe.

Claims (1)

[Scope of utility model registration request] A first flange is fixed to the outer circumferential surface of the end of the first pipe with a part protruding beyond the edge of the first pipe, and the first flange is fixed to the outer circumferential surface of the end of the first pipe, and the opposite side of the first flange to the first pipe is A mortar-shaped inclined surface is formed on the inner circumferential edge of the opening, a second flange is fixed to the outer circumferential surface of the end of the second pipe, and a refractory material is wound with a thin plate, and the second flange is connected to the second flange. The first flange and the second flange are aligned with each other while a closed annular sealing material having an inner diameter that can be freely fitted onto the end of the second protruding pipe is aligned with the mortar-shaped inclined surface. However, in a pipe connection using a flange, in which both the first and second pipes are joined in an air-tight and liquid-tight state by joining both flanges with bolts and nuts, the above-mentioned A pipe connection part using a flange, characterized in that a closed annular stepped part surrounding the entire circumference of the inclined surface and recessed from the side surface of the first flange is formed on the outer peripheral edge of the inclined surface.