JPH03161181A - Two-layer pipe and its manufacture - Google Patents

Abstract

PURPOSE:To improve sound insulation and damping capacity by forming a gap between an outer pipe and an inner pipe by iron-based material, nonferrous metal-based material or ceramic particles interposed between the outer pipe and the inner pipe. CONSTITUTION:The two-layer pipe is formed of the outer pipe 1 and the inner pipe 2. The iron-based material, the nonferrous metal-based material or the ceramics particles 3 are then interposed between the outer pipe 1 and the inner pipe 2. The gap is formed between the outer pipe 1 and the inner pipe 2 by these particles 3. The iron-based material, the nonferrous metal-based material or the ceramics particles are stuck by the thermal spraying method to the steel plate surface which is made to the outer pipe inner peripheral surface and the steel plate surface which is made to the outer peripheral surface of the outer pipe 1 or the inner pipe 2 after the pipe is manufactured and then, the two-layer pipe is formed. By this method, high pipe manufacturing efficiency can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a double-layer pipe used mainly for various types of pipes that generate noise, such as automobile exhaust pipes and air pipes, and a method for manufacturing the same.

[Conventional technology]

In recent years, progress has been made in the development of vibration-damping steel plates that have excellent sound insulation and vibration damping functions for various drive parts.

Allocation steel plates usually have a laminated structure in which a resin with high sound insulation and damping ability and a non-ferrous metal are sandwiched between the steel plates. It has been manufactured (Japanese Patent Application Laid-open No. 1-127184).

However, if we try to manufacture welded pipes using damping steel plates with such a laminated structure, the resin will gasify at the butt weld, creating bubbles, and non-ferrous metals will become alloyed at the weld, reducing the ductility of the weld. Currently, it is difficult to use it as a material for welded pipes because it deteriorates its toughness.

For this reason, welded pipes are made of steel plates that are stuck together! The two-layer pipe used, or the three-layer pipe with asbestos and glass wool sandwiched in the middle, and one or both of the steel plates are embossed, and the tip of the protrusion is brought into contact with the surface of one steel plate at the mating surface, leaving a gap between them. An embossed two-layer pipe with a
o. 2 224 true).

[Problem to be solved by the invention]

By the way, in the above-mentioned close-fitting two-layer pipe, the outer pipe and inner pipe are in close contact with each other, so the sound insulation against noise emitted through the pipe wall is low, and in the case of a three-layer pipe with a sound insulating material sandwiched in the middle, there is a problem when piping. When welding the pipes together, the sound insulating material melts or decomposes, creating bubbles. Furthermore, with embossed double-layer pipes, there are limits to the height and width of the protrusions, so if you try to increase the height or reduce the width of the protrusions, There were problems such as an increase in the degree of working at the protrusion and work hardening.

The present invention has been made in view of the above circumstances, and its purpose is to provide a two-layer pipe that is excellent in both sound insulation and damping ability, and a method for manufacturing the same.

[Means to solve the problem]

The two-layer tube according to the present invention consists of an outer tube and an inner tube, and the outer tube and the inner tube are connected by particles of ferrous material, non-ferrous metal material, or ceramics interposed between the outer tube and the inner tube. It is characterized by a gap being formed between the two.

Further, the method for manufacturing a double-layered pipe according to the present invention includes a method for manufacturing a two-layered pipe consisting of an outer pipe and an inner pipe, in which the surface of a steel plate that becomes the inner peripheral surface of the outer pipe and/or the outer peripheral surface of the inner pipe after pipe manufacturing is After attaching particles of ferrous material, non-ferrous metal material, or ceramics to the surface of each steel plate by thermal spraying, both I plates are stacked with a gap formed between them, and this stacked steel plate is shaped into a cylinder. It is characterized by being formed into a shape and welding the butt edges together.

(Function) According to the present invention, it becomes possible to appropriately set the gap between the steel plates, that is, the height and interval of the particles.

[Examples] The present invention will be specifically described below based on drawings showing examples thereof.

FIG. 1 is a partially enlarged cross-sectional view of a two-layer pipe according to the present invention,
In the figure, 1 indicates an outer tube, and 2 indicates an inner tube.

The outer tube "1" and the inner tube 2 are curved into concentric cylindrical shapes with particles 3 interposed between them, and their abutting edges are welded together to form a two-layered tube.

The particles 3 are fixed to either the inner circumferential surface of the outer tube 1 or the outer circumferential surface of the inner tube 2, and are distributed substantially uniformly as a whole at a predetermined height h and a predetermined distance 111d.

The hardness of the particles 3 is sufficient as long as it does not deform when shaping the pipe, and is similar to the material of the copper strip that is the pipe material. The material is selected depending on the type of pipe, and the melting point is higher than the temperature at which the double-layered pipe is used, such as ferrous materials, non-ferrous metals, ceramics, etc.

Particle height h. The distance between particles (pitch) d is related to these and sound insulation properties. Since there is a relationship with vibration damping properties as shown in Figures 2 and 3, it is set appropriately based on this. Figure 2 is a graph showing the relationship between the average height h of particles and the sound pressure level, with the horizontal axis representing the average height (M) and the vertical axis representing the sound pressure level (dB). .

As is clear from this graph, the sound pressure level decreases when the particle height is 0.05 circles or more, and it can be seen that the sound pressure level decreases rapidly as the particle height increases.

Figure 3 is a graph showing the relationship between the average distance between particles and the sound pressure level, with the horizontal axis representing the average distance R (m) between particles, and the vertical axis representing the sound pressure level (dB). . As is clear from this graph, a decrease in the sound pressure level is observed in the range of 2 to 7 m.

Normally, the sound insulation against radiated sound is the product h - d of height h and distance d.
The larger the distance d is, the larger the attenuation capacity is, and the smaller the distance d is, the larger the attenuation capacity is.

FIG. 4 is a graph showing the relationship between the height h of particles 3 and the distance d, with the horizontal axis representing the interparticle distance d, and the vertical axis representing the particle height h.
is shown. As is clear from this graph, the sound insulation improves as the distance d between attached particles and the height h of attached particles increase, but the shaded area is where problems arise in terms of processing conditions, allocation, and sound insulation function. Substantially, settings may be made in areas other than the shaded area.

Note that when h/d<a ((BLa: constant determined by the strength and wall thickness of the steel strip), the inner circumferential surface of the outer tube 1 and the outer circumferential surface of the inner tube 2 are This results in deformation in which the parts come into direct contact with each other, and conversely, the sound insulation and damping properties are impaired.

The formation of the particles 3 usually relies on plasma spraying, but is not limited to this, for example, arc spraying. gas spraying,
Instigated thermal spraying etc. can be applied.

However, when thermal spraying is used, there is a limit to the hub (where b is a constant determined by the thermal spraying material, thermal spraying conditions, etc.).

FIG. 6 is an explanatory diagram showing the implementation state of the method of the present invention, and 2
In the process of overlapping the copper strips 11 and 12 using roll l3, both steel plates 11. The steel plate 11. 12
Ferrous materials and non-ferrous metal materials on both surfaces. Particles 3 are formed by plasma spraying ceramics or the like.

Copper strip 11 with particles 3 formed thereon. 12 are stacked on top of each other with a gap formed, and then passed through a pipe-making roll (not shown) to be curved in the width direction, and both abutting edges in the width direction are welded together to produce a two-layer pipe.

FIG. 7 is a schematic diagram showing another method of manufacturing a two-layer pipe according to the present invention. A ferrous material or a non-ferrous metal material is sprayed from spray nozzles 24.25 facing the mating surfaces so that the particles 3 are deposited on both steel strips 21.22. The other steps are substantially the same as those in the embodiment illustrated in FIG. 6, and their explanation will be omitted.

In the above embodiment, the same material may be sprayed on both steel strips 2L22, or different materials may be sprayed on each, or a plurality of materials may be sprayed on each to form particles 3 of different materials. Of course.

[Test example]

Next, comparative tests conducted on the two-layer tube according to the present invention and other two-layer tubes, namely (1) a close-contact two-layer tube, (2) an embossed two-layer tube, (2) a single-layer tube, and (2) a thermally sprayed two-layer tube, and their results will be shown. In all cases, SUS410L was used as the copper strip serving as the pipe material. The thermal spraying conditions for manufacturing the double-layer pipe according to the present invention are as follows.

Thermal spraying method: Arc spraying method Thermal spraying material: SUS304 Thermal spraying current: 200A Thermal spraying distance: 400℃ Atomizing gas pressure: 1 ~ 5kg/d Atomizing gas nozzle diameter: 8 Peng Torch relative movement speed: 30m/min ~ 150m/min Atomizing gas The thermal spray particle diameter, that is, the particle height h, was varied by pressure, and the interparticle distance d was varied by the relative moving speed of the torch. Next, it was formed using a pipe-making roll as described above, and the edges of the steel plates were welded together to obtain a two-layer pipe.

The sound insulation and attenuation properties of the obtained test tubes were evaluated using the measuring device shown in Figure 8.9.

FIG. 8 is a schematic front view showing a measuring device for evaluation, and FIG. 9 is a side view thereof, in which a test tube 34 is suspended horizontally by a thin wire 33 from a support rod 32 passed between columns 31 and 31. At the same time, a steel ball (diameter 3
8 balls, weight 1235 g) 36 is suspended, and the steel ball 36 is made to collide with the circumferential surface of the test tube 34 in an arc from a position at an angle of 45 degrees to the perpendicular line, and the impact sound is emitted 40 m below the test tube 34.
Sound was collected by the microphone 37 set at the position of , and its sound insulation and attenuation properties were evaluated based on the collected sound. The measurement was performed in impulse mode, and the maximum instantaneous value of the impact sound was detected. The results are shown in Table 1.

(The following is a margin) Table ゛■ As is clear from Table 1, the examples of the present invention (Nos. 1 to 3) have lower sound pressure levels (
dB) is reduced. Note that conventional example No. 7
The embossed two-layer tube had work hardening on the protrusions.

〔effect〕

As described above, in the product of the present invention, particles are interposed between the outer tube and the inner tube, and a gap, that is, an air layer is formed between them, so that the sound insulation and damping ability are greatly improved. In addition, in the method of the present invention, iron-based material is applied to the surface of the steel plate that becomes the inner circumferential surface of the outer tube and/or the outer circumferential surface of the inner tube. Non-ferrous metal materials. The present invention has excellent effects such as thermal spraying of ceramics or the like to form particles and then stacking them to form pipes, so that the number of manufacturing steps increases only slightly and high pipe-manufacturing efficiency can be obtained.

[Brief explanation of the drawing]

Figure 1 is a partially enlarged sectional view of the product of the present invention, Figure 2 is a graph showing the relationship between the average height of particles and sound pressure level, and Figure 3 is a graph showing the relationship between average distance between particles and sound pressure level. Graph, Figure 4 is a graph showing the relationship between the distance between particles and particle height, Figure 5 is an explanatory diagram showing an example of a problem when the distance between particles is too wide,
Figure 6.7 is a schematic diagram showing the implementation state of the method of the present invention, Figure 8
The figure is a schematic front view of a measuring device for evaluating test results.
FIG. 9 is also a schematic side view thereof. 1... Outer tube 2... Inner tube 3... Particles 11.1
2... Steel strip l3... Roll 14... Thermal spray nozzle 21.22... Steel strip 23... Roll 24.25
...Thermal spray nostle patent applicant

Claims (1)

[Claims] 1. Consisting of an outer tube and an inner tube, particles of ferrous material, non-ferrous metal material, or ceramics are interposed between the outer tube and the inner tube. A double-layer pipe characterized by a gap formed therein. 2. In the method of manufacturing a double-layered pipe consisting of an outer pipe and an inner pipe, after the pipe is manufactured, iron-based coating is applied to the surface of the steel plate that will become the inner peripheral surface of the outer pipe and/or the surface of the steel plate that will become the outer peripheral surface of the inner pipe, respectively, by thermal spraying. After attaching the material, nonferrous metal material, or ceramic particles, the two steel plates are stacked with a gap formed between them, the stacked steel plates are formed into a cylindrical shape, and the butt edges are welded together. A method for manufacturing a double-layer pipe, characterized by: