JPH02125907A - Exhaust pipe coupling - Google Patents

Abstract

PURPOSE:To aim at the improvement of sealing performance, vibration absorbing effect and durability, etc., by arranging a gasket made of a reinforcing material and expansion graphite in an annular gap formed between the pipe end portion and the flange of an inner pipe, and the diameter enlargement portion of an outer pipe. CONSTITUTION:An exhaust pipe coupling comprises an inner pipe 1, an outer pipe 2 fitted on the circumference of the inner pipe 1 by some length from the opening portion 12 thereof, a cylindrical gasket 3 inserted in the gap of the fitting portion and a fastening band 4 fastened on the outer circumference of the outer pipe 2. In this case, an annular gap is formed by the outer circumference of the pipe end portion 13 of the inner pipe 1, one end of an annular flange 11 and the inner circumference of the diameter enlargement portion 21 of the outer pipe 2. The cylindrical gasket 3 comprising a reinforcing member and expansion graphite is arranged in the annular gap with remaining a space C closed by the gasket due to the heat expansion thereof at one end of the gap.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an exhaust pipe joint used in vehicles, and in particular to a plug-in type exhaust pipe joint.

Traditionally, plug-in type exhaust pipe joints, particularly used in vehicles such as automobiles and autopipes, fit a cylindrical gasket onto the outer circumferential surface of an inner pipe, and fit an outer pipe onto the outer circumferential surface of this gasket. After that, in order to improve the sealing performance between the outer circumferential surface of the inner tube and the inner circumferential surface of the outer tube, a type is known in which the outer circumferential surface of the outer tube is tightened with a tightening tool such as a band.

In addition, gaskets used in this type of pipe joint include, for example, gaskets made of metal plates (Utility Model No. 522930
5), a solid lubricant such as graphite powder is applied to the inner and outer peripheral surfaces of the sleeve, which is obtained by overlapping a metal plate and asbestos and winding them into a cylindrical shape, to prevent slipping and sticking. There are some known products that are coated with

This type of conventionally known plug-in type joint has advantages over other types, such as flange type, such as requiring less space and being easier to assemble. There was a problem in that it was disadvantageous against vibrations and heat generated by an internal combustion engine.

Therefore, an object of the present invention is to provide a new exhaust pipe joint that can solve these problems by improving the structure of the gasket and the joint.

t. In order to solve this problem, the present invention is characterized by the following configuration. That is, as shown in FIGS. 1 to 6 of the attached drawings, the inner tube (1) and the inner tube (1)
An annular gap formed between an outer tube (2) that is fitted into the outer circumferential surface of the outer tube (2) for a certain length from its opening (12), and the outer and inner circumferential surfaces of the fitted portions of these inner and outer tubes (1, 2). In an exhaust pipe joint, which consists of a cylindrical gasket (3) inserted in-plane and a tightening band (4) that is tightened and fixed to the outer circumferential surface of the outer pipe (2), the inner pipe (1) has a An annular flange 11) is provided in the vicinity of the opening (12), leaving a tube end portion (13) and protruding radially outward;
The outer tube (2) is provided with an enlarged diameter portion (2,) at the tube end, and a slot 7l' (2s) that is equally divided in the circumferential direction and extends in the axial direction in the enlarged diameter portion (21). The inner tube (1) has a tube end portion (l,) including the annular flange (11) fitted into the enlarged diameter portion (21) of the outer tube (2), and the inner tube is inserted into this fitted portion. An annular gap is formed by the outer circumferential surface of the tube end portion (1) of (1), one end surface of the annular flange (1,), and the inner circumferential surface of the enlarged diameter portion (21) of the outer tube (2). In this annular gap, a cylindrical gasket (3) made of reinforcing material and expanded graphite has one end in contact with one end surface of the annular flange (11), and the other end in contact with one end surface of the annular flange (11). The exhaust pipe joint is characterized by being arranged leaving a space (G) closed by the thermal expansion of the cylindrical gas scaler 1-(3).

1-Although the exhaust pipe joint according to the present invention has the above-described configuration, the exhaust pipe joint according to the present invention performs the following functions.

A cylindrical gasket (3) made of expanded graphite and a reinforcing material placed between the inner tube (1) and the enlarged diameter portion (21) of the outer tube (2) is made of flexible material that the expanded graphite has. It has the property of being flexible and flexible, and that one volumetric expansion occurs due to the heat of the high-temperature exhaust gas flowing inside the inner pipe (1). However, the volumetric expansion of this gasket (3) is limited because the expansion of the gasket (3) in the radially inward and radially outward directions is restricted by the inner tube (1) and outer tube (2), respectively. , appears as an expansion in its axial direction, and therefore, during assembly, the tube end portion (1,) of the inner tube (1) and
Gaskera 1-(3) other end surface 3. and the shoulder portion (2□) of the enlarged diameter portion (21) of the outer tube (2) (
G) is tightly occluded (see Figure 6). Therefore, the airtightness (sealability) there is improved. Note that, due to its nature, the thermally expanded gasket (3) does not return to its original state even if it is cooled, so this airtightness cannot be maintained at all times. be.

Hereinafter, the present invention will be described with reference to Nos. 1 to 6 of the attached drawings showing embodiments thereof.
A detailed explanation will be given based on the figures.

First, as shown in FIG. 1, the exhaust pipe joint according to the present invention includes an inner pipe 1, an outer pipe 2 into which it is inserted, an outer peripheral surface of the inner pipe 1, and an inner peripheral surface of the outer pipe 2. a sket 3 inserted into the annular space formed between the two, and a fastener 4 disposed on the outer peripheral surface of the enlarged diameter portion 2I of the outer tube 2 and tightening the inner and outer tubes 1.2 and the gasket 3 together. It is composed of.

First, as shown in FIG. 2, the inner tube 1 through which the high-temperature exhaust gas flows is formed from the opening 12 side to the tube end portion 1. The flange 11 is formed leaving the . In the embodiment of the exhaust pipe joint shown in FIG. 1, this flange 11 is fixed by fitting a ring 11° into the inner pipe 1 and pressing it radially inward. However, the fixation is not necessarily performed by such means, but can also be fixed by any other means such as welding.

Next, as shown in FIG. 3, the outer tube 2 has a main body portion 2° having an inner diameter that is approximately the same as the outer diameter of the inner tube 1, and a shoulder portion 22 between the main body portion 2° and a shoulder portion 22 at the tube end portion. A continuous diameter enlarged portion 21 is formed.

Opening portion 2 of diameter enlarged portion 21. By expanding the diameter enlarged portion 21 outward in the radial direction, the flange portion 2. is formed and an opening 2. From the enlarged diameter section 2. A large number of slits 2. are provided, but these slits 2. The length is such that it reaches almost the entire length of the enlarged diameter portion 2.

The flange portion 24 also has an opening 2. A cutout 26 having a rectangular cross section is provided so as to reach the vicinity of the enlarged diameter portion B around the periphery of the cutout 26 . In addition, this notch 2
6 is usually provided on one side, but in some cases several can be provided along the circumference.

In the inner tube 1 and outer tube 2 configured as described above, the inner tube 1 is placed inside the outer tube 2, and the tube end portion 1 of the inner tube 1 is placed inside the outer tube 2. , through the enlarged diameter portion 21 of the outer tube 2 and the main body portion 2 of the outer tube 2.
The inner tube 1 is inserted so as to extend up to 10.degree., and assembled so that an annular gap is formed between the outer circumferential surface of the inner tube 1 and the inner circumferential surface of the enlarged diameter portion 21 of the outer tube 2.

A cylindrical gasket 3 is arranged in an annular gap formed between the outer circumferential surface of the inner tube 1 and the inner circumferential surface of the enlarged diameter portion 21 of the outer tube 2.

The gasket 3 arranged in an annular gap is made of expanded graphite and a reinforcing material, and as shown in FIG. , and an inner peripheral surface 34.

Furthermore, the length of the gasket 3 is determined by the length of the inner peripheral surface 3. In the tube end portion 1. of the inner tube 1. The inner tube 1 extends almost the entire length of the outer circumferential surface of the inner tube 1 at one end surface 32.
Flange 1. , and on the other end surface 31,
A slight space G is formed between the enlarged diameter portion 21 of the outer tube 2 and the shoulder portion 22 (see FIG. 1), and the outer circumferential surface 3
．． , it has an outer diameter such that it comes into contact with the inner circumferential surface of the enlarged diameter portion 21 of the outer tube 2 .

The gasket 3 made of expanded graphite and the reinforcing material has the flexibility and bendability of expanded graphite, and also has the property of expanding in volume due to the heat of the exhaust gas flowing inside the inner tube 1. It also has the unique property that once its volume expands, it does not return to its original state even if it is cooled.

By arranging the gasket 3 having these properties in the annular gap described above, the volume expansion of the gasket 3 is caused by the volume expansion of the gasket 3 in the radially inward direction and in the radially outward direction, respectively.
Since it is constrained by the outer circumferential surface of This results in tightly closing the space G (see FIG. 6), which improves the airtightness (sealability) of the annular gap.

Here, the expanded graphite and reinforcing material that constitute this gasket 3 will be explained in some detail.

Expanded graphite is obtained by significantly expanding graphite in the C-axis direction of its crystals, and its specific manufacturing technology is described in U.S. Pat. Disclosed in official gazettes, etc. This expanded graphite powder can be easily manufactured into thin plates or blocks by pressurizing it without using a binder, and the resulting molded products are different from ordinary graphite. It is different, flexible, and deflectable. However, in terms of properties such as heat resistance, chemical resistance, and low coefficient of friction, there is no substantial difference from ordinary graphite. In addition, reinforcing materials include perforated metal plates, metal lath,
Alternatively, wire mesh can be used, but in particular, wire mesh obtained by knitting or weaving fine stainless steel wires has excellent heat resistance, and when combined with expanded graphite to form a molded product, the It is the most preferable material to be used in the present invention because it is not only difficult to impart directionality to objects, but also has high strength due to the entanglement of fine wires.

Gasket 3 having such composition or characteristics
In one direction, there is a sea I made of the above-mentioned expanded graphite,
The reinforcing material is overlapped with the reinforcing material, wound, and compressed and molded into a cylindrical shape in the winding direction using a pressure of about 100 to 3 per Cl112 in the winding direction.

Regarding the case of this example, the specific manufacturing method will be explained as follows.

First, an expanded graphite sheet with a thickness of 0.41 is
Cut it into strips to have the same length. Separately, prepare a stainless steel wire (SUS304) with a wire diameter of 0.2 mm, and knit it with a stockinette knit so that it has a stitch of about 5 cm^1 m and a width slightly narrower than the width of the expanded graphite sheet. By doing this, a wire mesh is made and placed.

This wire mesh is cut to a length approximately equal to the length of the expanded graphite sheet, and this is placed on top of the expanded graphite sheet. The expanded graphite sheets stacked in this manner and the wire mesh are wound at least twice around a cylindrical core metal with the wire mesh inside to form a cylindrical body.

This cylindrical body is placed in a mold, and the axial direction of the body is approximately 1.5 mm.
It is compressed and molded by applying a pressing force of t/am' (the compression ratio is about 70 $).

In this way, the stainless wire mesh as a reinforcing material is applied to the inner peripheral surface 3. exposed on both end surfaces 31, 32 and outer peripheral surface 33.
A gasket 3 as shown in FIG. 4 covered with expanded graphite is obtained.

Here, the inner peripheral surface 3. Gaskera 1- also has expanded graphite
If it is desired to obtain 3, prepare a length of wire mesh that is shorter than the length of the expanded graphite sheet by the amount of winding relative to the core metal, and overlap this with the expanded graphite sheet with one end aligned. A cylindrical body is made by first winding the expanded graphite sheet portion around the mandrel with the wire mesh on the inside, and then winding the wire mesh portion so as to overlap it. Then, compress and mold it.

After arranging the above-mentioned cylindrical gasket 3 in the annular gap formed between the outer and inner peripheral surfaces of the inner and outer tubes 1.2, the outer tube 2
By arranging the tightening band 4 on the outer peripheral surface of the tube and fastening the tightening band 4 with an appropriate fastener 5, the inner and outer tubes 1.2 and the gas keratin l-3 are firmly tightened together. .

As shown in FIG. 5, this tightening band 4 has a substantially cylindrical shape and is provided with a cut 4 along its axial direction. Ear portions 4□, 4□ are formed to protrude outward in the direction, and holes 4. are formed in these ear portions 4□. These holes 4. A fastener 5 such as a bolt is inserted into the fastener 5, and by tightening the fastener 5, the tightening band 4 is firmly tightened (see Fig. 1.6).

Furthermore, one end 45 of the axial ends 41 and 45 of the tightening band 4 is provided with a hook portion 46 that projects in the radial direction.
Enlarged diameter portion 2 of outer tube 2. Flange part 2. When fitted around the tube, the notch 26 formed in its flange portion 24 passes freely through, but its inner surface is adapted to contact the outer surface of the flange 11 of the inner tube 1.

Note that one hook portion 46 is normally provided, but
When there are multiple notches 26 provided in the flange portion 24 of the outer tube 2, the notches 2. A plurality of them can be provided corresponding to the number of the elements.

q The exhaust pipe joint according to the present invention, which is composed of the constituent members as described above, is assembled as follows.

That is, the inner tube 1 has a flange 1.1, leaving a tube end portion 1:l in the vicinity of its opening 12. is formed, and a cylindrical gasket 3 is attached to the tube end portion 13 of this inner tube 1.
One end face 32 of the flange 1. The outer tube 2 is inserted into the enlarged diameter portion 21 of the outer tube 2.

At this time, the other end surface 31 of the cylindrical gasket 3,
The outer tube 2 is inserted so that a slight space G remains between the shoulder portion 22 of the enlarged diameter portion 21 and the tube end portion 13 of the inner tube 1.

Next, the tightening band 4 is placed around the outer periphery of the enlarged diameter portion 21 of the outer tube 2, and the hole 4 of the ear portion 42 is tightened. By passing a fastener 5 such as a bolt through and tightening it, the tightening band 4 is tightened around the enlarged diameter portion 21, and the assembly is completed.

Here, the results of experiments conducted on the exhaust pipe joint according to the present invention will be explained.

That is, in this experiment, the test temperature was 600°C and the vibration frequency was 50.
Hertz, swing angle ±0.4° (inner tube fixed), gas pressure 0.
2kg/c+o2. The test was conducted under the conditions of 40 hours, and the results were as shown in the table below.

Person item Comparative product of the present invention Weight loss Gas leakage l/ani n 0.3 Gas keratin 1~ No significant change in appearance Oxidation/exhaustion Major deformation Note: Comparative product is made of asbestos sheet coated with a thin layer of ordinary graphite. It is layered with stainless wire mesh and wound into a cylindrical shape.

From the table above, it can be seen that the products of the present invention are superior in various properties as joints compared to comparative products.

[Fish] Giant Σ-class dish The present invention has the above-described structure and operation, and since the gasket has flexibility and flexibility, it can improve airtightness and has a vibration absorption effect. In addition, the gasket has the property of expanding in volume due to the heat of the high-temperature exhaust gas flowing through the inner tube, so the volumetric expansion of the gasket causes the end portion of the inner tube to , the space formed by the end faces of the gas keras 1 and the shoulders of the enlarged diameter portion of the outer tube can be tightly closed, and the airtightness of this space can be improved.

In addition, Gaskera 1 has excellent structural integrity between expanded graphite and reinforcing material, so it has high resistance to mechanical and thermal stress, and has excellent oxidation resistance at high temperatures. .

Furthermore, since asbestos is not used in the present invention, in view of the current situation where the use of exhaust pipe joints made of asbestos is prohibited due to pollution problems, an alternative type of exhaust pipe is proposed. As a pipe fitting, especially
It is something that can be said to be excellent.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of the exhaust pipe joint according to the present invention in its assembled state, FIG. 2 is a perspective view showing the inner pipe portion thereof, and FIG. FIG. 4 is a perspective view showing the gasket, FIG. 5 is a perspective view showing the tightening band, and FIG. 6 is the same as FIG. 1, but shows the exhaust pipe joint. It is a partial longitudinal section shown in a state after use. 1.Inner pipe, 11..flange, 12..opening, 1..
・・Pipe end portion, 2・・Outer tube, 2o Main body portion, 21・
Expanded diameter part, 2□... Shoulder part, 23... Opening, 2, Flange part, 25, Slit l-126... Notch, 3
・Gasquera 1-13. ．． 32・End surface, 33...Outer circumference surface, 3...Inner circumference surface, 4...Tightening band, 41・Slit, 4□...Ear part, 43...Hole, 44.4s...End part, 46. Hook part, 5. Fastener, G... Space part. Patent applicant Honda Motor Co., Ltd. Same as above Oiles Industries Co., Ltd.

Claims (1)

[Scope of Claims] 1. An inner tube, an outer tube fitted into the outer peripheral surface of the inner tube for a certain length from its opening, and an annular gap formed at the fitting portion of the inner tube and the outer tube. In an exhaust pipe joint, which consists of a cylindrical gasket inserted into the inner pipe and a tightening band that is tightened and fixed to the outer circumferential surface of the outer pipe, the inner pipe is attached to the inner pipe in the radial direction, leaving the pipe end near the opening. An outwardly projecting flange is provided, and the outer tube has a
The tube end portion is provided with a diameter enlarged portion and the diameter enlarged portion is provided with slits that are equally divided in the circumferential direction and along the axial direction, and the tube end portion including the flange of the inner tube is It is fitted into the enlarged part, and an annular gap is formed in this fitted part by the outer circumferential surface of the tube end portion of the inner tube, one end surface of the flange, and the inner circumferential surface of the diameter enlarged part of the outer tube. Inside the annular gap, a cylindrical gasket made of reinforcing material and expanded graphite has one end in contact with one end face of the flange of the inner tube, and the other end is closed by thermal expansion of the cylindrical gasket. An exhaust pipe joint characterized in that the exhaust pipe joint is arranged leaving a space in which the exhaust pipe is removed.