JPH07100987A - Damping metal pipe - Google Patents

Abstract

(57) [Summary] [Purpose] A vibration-damping metal pipe with a close-contact double-pipe structure that excels in heat resistance and vibration damping. A damping metal pipe formed by laminating a plurality of metal pipes, wherein at least one of the laminated surfaces of the inner layer and the outer layer is roughened to have a surface roughness of 5 to 10 μmRz. . Since the surface roughness of at least one of the laminated surfaces of the inner layer and the outer layer is set to 5 to 10 μmRz, the friction resistance at the contact surface between the inner tube and the outer tube becomes large, and the friction energy increases accordingly, so that the larger The vibration damping effect can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration-damping metal pipe having excellent vibration-damping properties and heat resistance, which is used for automobile exhaust gas parts or various industrial machines.

[0002]

2. Description of the Related Art In recent years, noise regulation has been taken up as a social demand, and accordingly, damping steel sheets have come to be used in automobiles and industrial machines which are sources of noise. The vibration-damping steel plate is a steel plate that has a vibration-damping function by compounding functions or alloying without impairing the strength, toughness, and workability of the steel plate, and is a vibration-damping material that also serves as a structural member.

A damping alloy that also serves as a structural member is Mn-C.
u alloy is well known, but Mn-Cu alloy has 50
Vibration damping performance deteriorates at -60 ° C or higher, and residual stress must be removed because it is sensitive to strain. In addition, although ferritic stainless steel, which represents the alloy type damping steel sheet, retains its performance up to 350 ° C or higher, it is sensitive to strain and it is essential to remove residual stress after processing, and the damping mechanism is the domain wall. Therefore, the performance is lost when a magnetic field of about 40 Oe is applied.

On the other hand, the composite type vibration-damping steel plate has extremely high vibration-damping performance and is not affected by distortion. This composite type vibration damping steel plate has a three-layer structure composed of steel plate / viscoelastic resin / steel plate, and the vibration damping mechanism is made of resin that accompanies bending vibration of the steel plate.
It utilizes viscoelasticity based on "Shear". However, since this composite type vibration damping steel plate uses viscoelastic resin, it has temperature dependence and frequency dependence.
There is a drawback that the rigidity changes with temperature, and at most 130
It can only be used at temperatures up to ℃.

However, the necessity of preventing noise and vibration is not limited to the above-mentioned temperature or lower, and the emergence of a vibration damping material which can withstand use at higher temperatures and has excellent vibration damping characteristics. . For example, an exhaust gas component of an automobile is repeatedly subjected to vibration during running, heating and cooling, and the component is required to have excellent vibration damping properties and heat resistance. Exhaust parts for automobiles are exposed to a high temperature of 400 to 600 ° C., and the composite type vibration damping steel plate cannot exhibit sufficient vibration damping property at such a high temperature, and also has poor heat resistance. It cannot withstand use as a damping material for automobile parts or industrial equipment.

Therefore, as a damping steel plate that can withstand high temperatures,
Superplastic alloy laminated plates and metal core composite type damping steel plates have been proposed. For example, in the invention of a vibration-damping metal plate disclosed in Japanese Patent Laid-Open No. 63-99937, the metal plates are metallurgically bonded to each other by uniformly biting inclusions such as fine ceramics between the metal plates. A steel plate that abuts in a non-contact state and has excellent vibration damping properties is obtained.

However, all of these proposals are formed as a plate material, are difficult to process into a pipe or the like, and are not suitable for a damping metal pipe. Therefore, what is proposed to solve this problem is a close contact double tube, in which at least two pipes are laminated inside and outside and pulled out and brought into close contact with each other as shown in FIG.

In this close contact double tube, the inner tube and the outer tube, which are in close contact with each other, vibrate at their own vibration frequencies due to a mechanical shock from the outside. However, since the inner tube and the outer tube do not have an integral structure, they do not vibrate synchronously, and a deviation occurs in the vibration at the contact surface between the inner tube and the outer tube. It is stopped by and is consumed as frictional energy, and the damping effect is exerted.

In addition, as a vibration-damping metal pipe and a manufacturing method, Japanese Unexamined Patent Publication No. 58-57944 discloses that a Ni-based metal pipe and a Ti-based metal pipe are fitted into the other, and then the diameters of both pipes are reduced to form a joined pipe. There is disclosed a vibration-damping metal pipe in which a body is obtained, and the Ni-Ti intermetallic compound having excellent vibration damping performance is formed by heating the pipe body and diffusing at the interface between the Ni-base metal pipe and the Ti-base metal pipe.

[0010]

However, the conventional contact double pipe is a pipe in which the same material is piled up and cold drawn and the outer pipe and the inner pipe are brought into close contact with each other. There is not much difference between the two, and the vibration peak can be suppressed compared to the single pipe, but the damping property was not yet sufficient. Further, in a vibration-damping metal pipe in which a Ni-based metal pipe and a Ti-based metal pipe are joined and heated, a component system is limited and an operation of heating is required.

The present invention has been made in order to solve the problem that the vibration damping property of the conventional vibration damping metal pipe is still insufficient, and the vibration damping property is further enhanced as compared with the conventional vibration damping metal pipe. The purpose is to provide a damping metal tube.

[0012]

[Means for Solving the Problems] The close contact double pipe exerts a vibration damping effect because the vibration is deviated at the contact surface between the inner pipe and the outer pipe as described above and is consumed as friction energy. is there. Therefore, the inventors of the present invention conducted intensive research based on the idea that the damping effect would be improved by increasing the frictional energy. As a result, the inner surface of the outer tube and the outer surface of the inner tube are finished by the conventional surface finishing No. 2D (JIS G4305, surface roughness;
(1 to 2 μm), by setting the surface roughness to 5 to 10 μm, the frictional resistance at the contact surface between the inner pipe and the outer pipe increases, and the frictional energy increases accordingly, resulting in a large vibration damping effect. The present invention has been completed by finding that it can be obtained.

The vibration damping metal pipe of the present invention is a vibration damping metal pipe in which a plurality of metal pipes are laminated, and at least one of the laminated surfaces of the inner layer and the outer layer has a surface roughness of 5 to 10 μmR.
The point is that the surface is roughened to z.

In order to obtain a desired surface roughness on the metal pipe, any method such as cutting, grinding or etching may be used. As the metal pipe used in the present invention, ferritic stainless steel, ordinary steel, copper, aluminum and the like can be used. There is no particular limitation on the method of closely contacting the outer tube with the outer circumference of the inner tube, as long as the outer tube can be brought into close contact with the outer circumference of the inner tube by some method. For example, the inner tube may be inserted into the outer tube and then pulled out as it is to bring the outer tube into close contact with the inner tube, or conversely, the inner tube may be expanded in diameter to be brought into close contact with the outer tube. good.

It is preferable that the natural vibration frequency of the metal tube used for the outer layer and the natural vibration frequency of the metal tube used for the inner layer are different as much as possible. The natural vibration frequency may be changed by any means such as changing the mass, changing the wall thickness, or changing the material. Further, the outer layer metal tube and the inner layer metal tube do not have to be each single layer, and may be multiple layers.

[0016]

In a damping metal pipe formed by laminating a plurality of metal pipes, at least one of the laminated surfaces of the inner layer and the outer layer has a surface roughness of 5 to 10 μmRz. Since the resistance increases and the friction energy increases accordingly, a greater vibration damping effect can be obtained.

In the present invention, in order to obtain a sufficient vibration damping effect, it is necessary to set the surface roughness to 5 to 10 μm. Figure 4 shows the pipe surface roughness (10-point average) Rz (μm)
FIG. 5 is a diagram showing the result of measuring the relationship between the peak height of vibration (dB) and, as is clear from FIG. 4, when the surface roughness exceeds 10 μm, the frictional resistance becomes too large and the inner tube It becomes difficult for the outer tube to come into contact with the contact surface of the outer tube, and on the contrary, the friction energy is reduced, so that the vibration damping effect is not sufficiently exerted. On the other hand, when the surface roughness is less than 5 μm, the frictional resistance is small, the frictional energy is small, and it is difficult to obtain the vibration damping effect.

[0018]

EXAMPLES The effects of the present invention will be clarified by comparing the examples of the present invention with a single pipe and a conventional double pipe. As shown in FIG. 1, as an example of the present invention, an inner pipe 2 was obtained by processing the surface roughness of the outer surface of a steel pipe made of SUS 430J1L and having an outer diameter of 49.8φ × 1.0 mmt to 6 μmRz. Separately, S
Outer diameter 50.8φ x 1.0m made of US 430J1L
The surface roughness of the inner surface of the mt steel pipe was processed to 6 μm Rz to obtain the outer pipe 1. The inner pipe 2 is inserted into the outer pipe 1, and the outer pipe 1 and the inner pipe 2 are brought into close contact with each other by cold drawing to have an outer diameter of 50.8 m.
A vibration-damping metal pipe having a thickness of 2.0 mm and a thickness of 2.0 mm was manufactured. Note that the cold drawing is for the purpose of closely contacting the inner and outer metal pipes, and is a slight plastic working, so the change in wall thickness is slight.

For comparison, as a conventional example, SUS430
A single tube made of JIL and having an outer diameter of 50.8 mm and a wall thickness of 2.0 mm, and as shown in the perspective view of FIG. 2, SUS430JI
The outer tube 1 made of L and having a thickness of 1.0 mm is also provided with SUS4.
Insert a 30 JIL thick inner tube 2 with a thickness of 1.00 mm and bring the outer tube 1 and the inner tube 2 into close contact by cold drawing, and a simple close contact double tube with an outer diameter of 50.8 mm and a wall thickness of 2.0 mm A structural damping metal pipe was manufactured.

The damping properties of the manufactured damping metal pipe of this embodiment, conventional damping metal pipe and single pipe were evaluated. In order to evaluate the vibration damping property, the vibration state when these pipes were hung with a thread and hit with a hammer with the same strength was subjected to FFT frequency analysis, and the peak heights of the vibrations were compared. The frequencies A to E correspond to frequencies at which a peak between 0 and 10 kHz occurs. The obtained results are shown in FIG.

As shown in FIG. 3, the embodiment of the present invention is
Although there was no difference in peak height at some frequencies and there was no damping effect, the peak height of vibration was significantly lower than that of the conventional single tube or simple contact double tube structure, It has excellent vibration damping properties as a whole, and the effect of the present invention was confirmed.

[0022]

As described in detail above, the vibration-damping metal pipe of the present invention is a vibration-damping metal pipe in which a plurality of metal pipes are laminated, and at least one of the laminated surfaces of the inner layer and the outer layer is a surface. It is characterized in that the surface is roughened to a roughness of 5 to 10 μmRz. Since the surface roughness of at least one of the laminated surfaces of the inner layer and the outer layer is set to 5 to 10 μmRz, the frictional resistance at the contact surface between the inner tube and the outer tube is increased, and the friction energy is increased accordingly. The vibration damping effect can be obtained.

[Brief description of drawings]

FIG. 1 is a perspective view illustrating a structure of a vibration damping metal pipe of the present invention.

FIG. 2 is a perspective view illustrating a method for manufacturing a close contact double tube.

FIG. 3 is a diagram showing the frequency and the height of a vibration peak of the pipe of the example of the present invention and the pipe of the conventional example.

FIG. 4 is a diagram showing the results of measuring the relationship between the surface roughness (10-point average) Rz (μm) of vibration and the peak height (dB) of vibration.

[Explanation of symbols]

 1 outer tube 2 inner tube

Claims (1)

[Claims] 1. A vibration-damping metal pipe formed by laminating a plurality of metal pipes, wherein at least one of the laminated surfaces of the inner layer and the outer layer is roughened to have a surface roughness of 5 to 10 μmRz. And damping metal pipe.