JP2004285849A - Method for installing flexible heat insulating pipe to exhaust pipe of automobile, and spacer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent breakage caused by friction of an exhaust pipe of an automobile with a flexible heat insulating pipe. <P>SOLUTION: Spacers are disposed at arbitral intervals on an outer circumferential face of the exhaust pipe of the automobile, and the flexible heat insulating pipe is installed to the exhaust pipe through the spacers. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for mounting a flexible heat insulating pipe used to insulate an exhaust pipe of an automobile, and a spacer used for the method.
[0002]
[Prior art]
Generally, exhaust gas of an automobile engine is sent to a catalytic converter through an exhaust pipe, and is discharged from a muffler to the atmosphere after removing air pollutants by the catalytic converter. In the catalytic converter, it is desired that the exhaust gas temperature is high from the viewpoint of the efficiency of the catalytic reaction, and the exhaust pipe is thermally insulated to prevent the temperature of the exhaust gas from decreasing until reaching the catalytic converter. . Further, the same heat insulation is performed on the EGR pipe for sending the exhaust gas to the intake side again.
[0003]
Conventionally, as a method of insulating the exhaust pipe, a method of attaching a pressed heat shield plate or a flexible heat insulating pipe to the exhaust pipe has been adopted. Since the heat shield plate, which is a press-processed product, requires the production of a press die for molding each time the shape of the exhaust pipe changes, it is uneconomical and inefficient. A method of mounting a flexible heat insulating pipe that can follow is used frequently, and various flexible heat insulating pipes have been proposed (for example, see Patent Documents 1 and 2).
[Patent Document 1]
Japanese Utility Model Publication No. 51-119008 [Patent Document 2]
JP-A-58-102883 [0004]
[Problems to be solved by the invention]
However, the conventional method of attaching a flexible heat insulating pipe to an exhaust pipe of a vehicle simply attaches a flexible heat insulating pipe having a diameter larger than that of the exhaust pipe to the outside of the exhaust pipe. There is a problem that the exhaust pipe and the flexible heat insulating pipe constantly rub against each other due to the internal vibration, and the flexible heat insulating pipe is damaged. In particular, in the exhaust pipe provided with the bellows, since the periphery of the bellows is also directly covered with the flexible heat insulating pipe, the ridges of the bellows and the flexible heat insulating pipe are rubbed against each other. Damage is likely to occur.
[0005]
An object of the present invention is to prevent breakage of a flexible heat-insulating pipe due to friction with an exhaust pipe in view of the above conventional situation.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a method for mounting a flexible heat insulating pipe for covering an exhaust pipe of an automobile, wherein a spacer is fixed to an outer peripheral surface of the exhaust pipe at arbitrary intervals, and the And mounting the flexible heat insulating pipe on an automobile exhaust pipe.
[0007]
The present invention also provides a spacer used in the above-mentioned method of attaching a flexible heat insulating pipe to an automobile exhaust pipe, wherein the spacer is a tape or a mat made of a heat resistant material. The present invention provides a spacer which is a molded body made of a material and provided with a body for filling a gap between the exhaust pipe and the flexible heat-insulating pipe.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings.
[0009]
In the present invention, there is no limitation on the flexible heat insulating pipe, and all kinds of conventionally known flexible heat insulating pipes can be targeted.
[0010]
In the method for mounting a flexible heat insulating pipe of the present invention, the flexible heat insulating pipe is mounted on the exhaust pipe via a spacer. Basically, the spacer forms a gap between an opening through which the exhaust pipe is inserted (hereinafter referred to as an “exhaust pipe insertion portion”) and an outer peripheral surface of the exhaust pipe and an inner peripheral surface of the flexible heat insulating pipe ( There is no restriction on the shape as long as it has the following “body part”), and for example, it can be shaped as illustrated in FIGS. 1 (a) to 1 (c). FIG. 1A shows a ring-shaped or cylindrical spacer A in which an exhaust pipe insertion portion 1 is provided at the center of a disk-shaped main body 2. FIG. 1B shows the main body 2 in a planar shape of a regular polygon (a regular hexagon in the figure). In this spacer A, the corners may be chamfered in a flat or arc shape. FIG. 1C shows the main body 2 in a gear shape.
[0011]
In addition, although illustration is omitted, in the spacer A of FIG. 1B, the plane shape may be an equilateral triangle or a square. In the spacer of FIG. In addition to a rectangular shape, the shape may be a triangle (a star shape as a whole).
[0012]
In each spacer A, the diameter D ₁ of the exhaust pipe insertion portion 1 sets an outer diameter the same or slightly less of the exhaust pipe to be mounted, the outer diameter D ₂ of the main body portion 2 is the same as the inner diameter of FLEXIBLE heat-insulated pipe or Set slightly larger. The width W of the spacer A is arbitrary, but the wider the width, the greater the frictional resistance when inserted into the flexible heat insulating tube. From the viewpoint of the frictional resistance, it can be said that the spacer A in which the main body 2 has a polygonal shape as shown in FIG. 1B having a small contact area with the flexible heat insulating pipe is preferable. Further, even if the entire outer peripheral surface of the main body 2 is in contact with the flexible heat insulating tube as shown in FIG. By adhering a vinyl tape having a smooth surface, an increase in frictional resistance can be prevented.
[0013]
Further, in addition to the molded body having the predetermined shape as described above, the spacer is formed into a tape shape or a mat shape, and is wound around the exhaust pipe a plurality of times so as to have a thickness corresponding to a gap between the exhaust pipe and the flexible heat insulating pipe. It can also be.
[0014]
Further, it is preferable that the spacer A has heat resistance enough to withstand the temperature of the exhaust pipe during operation of the engine and moderate elasticity. Therefore, the spacer A is made of an inorganic fiber such as a basalt fiber, a glass fiber, a silica fiber, a ceramic fiber, an alumina fiber, a mullite fiber, a stainless steel fiber (a fiber such as SUS304, SUS316, SUS310S, SUS430, SUS409, SUS410), an inconel fiber, or the like. Metal fibers, inorganic biosoluble fibers, or a mixture of these fibers. The inorganic fibers can be formed into a needle mat shape, for example, and an inorganic binder can be used for shaping. The metal fiber may be a knitted fabric or a molded product obtained by molding it into a predetermined shape such as a needle mat shape.
[0015]
Next, a method of attaching a flexible heat insulating pipe to an exhaust pipe using the spacer A will be described. FIG. 2 is a cross-sectional view schematically showing an example of the embodiment. First, the above-mentioned spacers A are arranged at appropriate intervals in the exhaust pipe 10. Next, the spacer A is fixed to the outer peripheral surface of the exhaust pipe 10 by using an adhesive or a metal by welding so that the spacer A does not move when the flexible heat insulating pipe is mounted. Then, the mounting is completed by inserting the exhaust pipe 10 with the spacer A into the flexible heat insulating pipe 20 as usual. At the time of insertion, since the spacers A are arranged at intervals, the increase in frictional resistance due to the spacers A is not so large and does not hinder the work. In particular, in the polygonal spacer A as shown in FIG. 1B, only the corners are in contact with the flexible heat insulating pipe 20 and are almost in linear contact. It is almost the same as the conventional method not using A.
[0016]
When the exhaust pipe 10 has a curved portion, the exhaust pipe 10 and the flexible heat insulating pipe 20 approach each other near the curved portion, so that the spacer A is disposed before and after the curved portion as illustrated. It is preferable to install them. In addition, it is preferable to dispose the spacer A near both openings of the flexible heat insulating tube 20. In particular, when a spacer A as shown in FIG. 1A or a tape or mat-shaped spacer is wound, the gap between the exhaust pipe 10 and the flexible heat insulating pipe 20 is closed by the spacer A, Intrusion of foreign matter from the outside can be prevented.
[0017]
Further, as shown in FIG. 3, although the spacer A of the likewise present invention in the case of an exhaust pipe 10 provided with a bellows 15 can be used, in which the outer diameter D ₂ of the spacer A than the outer diameter D of the bellows 15 Also increase. As a result, the crest portion 15a of the bellows 15 does not contact the inner peripheral surface of the flexible heat insulating tube 20, and the flexible heat insulating tube 20 is not damaged.
[0018]
【Example】
Hereinafter, the present invention will be further described with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.
[0019]
(Examples 1 to 6, Comparative Example 1)
A total of four spacers described below were attached at both ends and at equal intervals between the exhaust pipes having an outer diameter of 40 mm and a length of 550 mm to which bellows having an outer diameter of 49 mm were attached. Then, the exhaust pipe with the spacer was inserted into a flexible insulating tube (“N-flexible tube GA type” manufactured by Nichias Corporation) made of glass cloth and aluminum foil having a minimum diameter of 55 mm, a maximum diameter of 60 mm, and a length of 500 mm. .
[0020]
〔Spacer〕
- Example 1: Metal (stainless steel (SUS316L)) textile felt (Nippon Seisen Co., Ltd., "NASLON felt"; 1500 g / ^{m 2)} having a thickness of 5 mm, 2 double winding the tape width 20mm exhaust pipe periphery This was used as a spacer.
- Example 2: metal fiber wool (Kanto steel wire Ltd. "stainless ^{wool"; 800g / m 2; 60W ×} 75μm) were laminated to a thickness of 10mm was used as a spacer.
- Example 3: metal fiber needle mat (Yazawa Sangyo Co. was spacers are laminated so that the "SUS wool needle ^{mat; 800g / m 2; 60W ×} 75μm " thickness 10 mm.
Example 4: Using a SUS mesh (“Soft Mesh” manufactured by Nichias Corporation; 2.5 kg / m ³ ), formed into a ring shape having an inner diameter of 40 mm, an outer diameter of 54 mm, and a width of 5 mm (see FIG. 1A). This was used as a spacer.
- Example 5: mullite fibers needle mat (manufactured by Mitsubishi Chemical Functional Products Capital Corporation "muff Tech blanket MLS-2"; 130 g / ^{m 3,} a thickness of 12.5 mm) punched out was a spacer. The width is 50 mm.
- Example 6: (manufactured by NICHIAS Corporation "T / # 4517-P glass mat pipe"; 180 g / ^{m 3)} glass mat pipe with an inner diameter Fai39mm, outer diameter 50 mm diameter, a ring-shaped width 50 mm (Fig. 1 ( a)) to form a spacer.
Comparative Example 1: No spacer was used.
[0021]
Then, the insertability of the exhaust pipe when the flexible heat insulating pipe was mounted as described below, and the durability of the flexible heat insulating pipe mounted on the exhaust pipe were evaluated.
[0022]
-Insertability: When inserting the exhaust pipe into the flexible heat insulating pipe by hand, the insertability was evaluated from the magnitude of the force required for insertion. As a result, the exhaust pipes of Examples 1 to 6 could be inserted with the same force as inserting the exhaust pipe of Comparative Example 1 into the flexible heat insulating pipe.
-Durability: After leaving it in an oven at 500 ° C for 8 hours with a flexible heat insulating tube attached to the exhaust pipe, a vibration durability test was performed with a vibrator. Vibration conditions for the above, 100 Hz, were vibrated 20G, 10 ⁷ times. As a result, none of the examples in which the spacers of Examples 1 to 6 were interposed had any damage to the flexible heat insulating tube. On the other hand, in the case of Comparative Example 1 in which the spacer was not interposed, cracks occurred in the portion of the flexible heat insulating tube facing the bellows.
[0023]
【The invention's effect】
As described above, according to the present invention, a constant gap is formed and maintained between the exhaust pipe and the flexible heat insulating pipe by the spacer, so that the exhaust pipe and the flexible heat insulating pipe come into direct contact with each other. In addition, it is possible to prevent the flexible heat insulating tube from being damaged due to friction between the two. Further, since an air layer is formed between the exhaust pipe and the flexible heat insulating pipe, the heat insulating effect is also improved. Furthermore, by using a cylindrical or tape-wrapped spacer, the gap between the exhaust pipe and the flexible heat insulating pipe is closed, and entry of foreign matter into this gap can be prevented.
[Brief description of the drawings]
FIG. 1 is a perspective view illustrating a spacer of the present invention.
FIG. 2 is a cross-sectional view showing an example of a manner of mounting the flexible heat insulating tube of the present invention.
FIG. 3 is a sectional view showing another example (an exhaust pipe with a bellows) of a mounting style of a flexible heat insulating pipe of the present invention.
[Explanation of symbols]
A Spacer 1 Exhaust pipe insertion section 2 Main body section 10 Exhaust pipe 15 Bellows 20 Flexible heat insulating pipe

Claims (5)

A method of mounting a flexible heat insulating pipe covering an exhaust pipe of an automobile, wherein a spacer is fixed to an outer peripheral surface of the exhaust pipe at an arbitrary interval, and the flexible heat insulating pipe is mounted via the spacer. A method of attaching a flexible heat insulating pipe to an automobile exhaust pipe. A spacer used in the method for mounting a flexible heat insulating pipe on an automobile exhaust pipe according to claim 1, wherein the spacer is a tape or a mat made of a heat resistant material. A spacer used in the method for mounting a flexible heat insulating pipe on an automobile exhaust pipe according to claim 1, wherein the spacer is made of a heat-resistant material, and the insertion section of the exhaust pipe, the exhaust pipe, and the flexible pipe. A spacer formed of a molded body having a main body that fills a gap with the heat insulating pipe. The spacer according to claim 2 or 3, wherein the heat-resistant material is an inorganic fiber, a metal fiber, or a fiber mixture of an inorganic fiber and a metal fiber. The spacer according to any one of claims 2 to 4, wherein an outer diameter of the spacer is larger than an outer diameter of a bellows pipe of an automobile exhaust pipe.

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