JPH02180397A - Damping compound metal pipe - Google Patents

Abstract

PURPOSE:To absorb vibration energy as frictional energy at a joint portion to obtain damping effect by covering an inner tube and the outer circumference of the inner tube at least over half circle thereof to closely adhere an outer tube. CONSTITUTION:An inner tube 10 and an outer tube 11 closely adhered each other vibrate at respective natural frequency due to a mechanical shock from the outside, but they do not vibrate synchronously because of no united body. Since the slippage of the vibration is generated at the contact face, one of the vibration is restrained by the other tube to spend as frictional energy for showing damping effect. The inner tube is an entire tube wherein no ribet holes, etc are bored when the outer tube is closeld adhered thereto so that is no anxiety completely such that fluid flowing in the tube leaks. The damping compound metal pipe has no temperature dependence and no damping effect deteriorates at a high temperature. Moreover, there is no necessity to take account of sensibility for deformation.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a vibration-damping composite metal tube with excellent vibration-damping properties and heat resistance used in automobile exhaust gas components or various industrial machines. .

[Background Art] In recent years, noise regulations have been taken up as a social requirement, and vibration damping steel plates have come to be used in automobiles and industrial machinery, which are the sources of noise. A vibration-damping steel plate is a steel plate that has been given a vibration-damping function by combining functions or alloying without sacrificing the strengths of the steel plate, such as strength, toughness, and workability, and is a vibration-damping material that also serves as a structural member.

Mn-Cu alloy is well known as a damping alloy that also serves as a structural member.
The more damping performance deteriorates at temperatures above 0°C, the more sensitive it is to distortion, so it is necessary to remove residual stress. In addition, although ferritic stainless steel, which is representative of alloy-type vibration damping steel sheets, maintains its performance up to temperatures above 350°C, it is sensitive to distortion and requires the removal of residual stress after processing, and the damping mechanism is based on magnetic domain walls. Due to this, there is a property that the performance is lost when a magnetic field of about 400 e is applied.

On the other hand, composite vibration damping steel plates have extremely high vibration damping performance and are unaffected by distortion.
It has a three-layer structure consisting of viscoelastic resin/steel plate, and the vibration damping mechanism uses the "shear" (Sl) of the resin due to bending vibration of the steel plate.
It utilizes viscoelasticity based on +ear)'. However, since this composite damping steel plate uses viscoelastic resin, it has temperature dependence and frequency dependence, and has the disadvantage that its rigidity changes depending on temperature, so it can only be used at temperatures up to 130"C. I can't stand it.

[Issues to be solved by the invention] However, the need for noise and vibration prevention is not limited to temperatures below the above-mentioned temperature, and there is a need for vibration damping materials that can withstand use at higher temperatures and have excellent damping properties. For example, automobile exhaust gas parts are subject to repeated vibrations, heating, and cooling during driving, and these parts are required to have excellent vibration damping properties and heat resistance. There is. 40 car exhaust parts
It is exposed to temperatures of 0 to 600 degrees Celsius, and the above-mentioned composite vibration damping steel sheets not only cannot exhibit sufficient vibration damping properties at such high temperatures, but also have poor heat resistance, making them suitable for automotive parts and other applications. It cannot withstand use as a damping material for industrial equipment.

Prior art proposed to solve the above problems includes:
There is an invention filed by the applicant on August 31, 1985, the gist of which is a pipe in which at least two metal plates are laminated, and in the laminated state, these metal plates can be attached with rivets, etc. This is a vibration-damping composite metal pipe characterized by being joined by.

However, in the prior art, since rivets are used to join the metal plates, the rivet hole penetrates the metal pipe and the contents of the pipe leak.

The present invention was made in view of the above-mentioned problems of conventional vibration damping steel plates and damping multi-layer vibration damping vibration damping devices. To provide a vibration-damping composite metal pipe with durable vibration-damping properties, heat resistance, collapse, and good airtightness without leaking the contents of the pipe.

[Means for Solving the Problems] The present inventors focused on the fact that although each flIl construction member and furnace member and shape vibrate at a unique frequency, they do not vibrate synchronously unless the structural members are integrated. The present invention has been completed by discovering that by dividing this structural member into several parts and joining them together, vibration energy can be absorbed as frictional energy at the joined parts and a damping effect can be exerted.

The gist of the vibration-damping composite metal tube of the present invention is that it consists of an inner tube and an outer tube that is tightly attached to the inner tube so as to cover at least half of the outer circumference of the inner tube.

As the metal tube used in the present invention, ferritic stainless steel, common steel, copper, aluminum, etc. can be used. Although the inner tube is required to be a complete tube, the outer tube that is closely attached to the outer circumference of the inner tube does not need to be a complete tube; it is sufficient that the outer tube covers at least half the circumference of the inner tube. If the outer tube is less than half the circumference of the inner tube, sufficient vibration damping performance will not be exhibited.

There are no particular restrictions on the method of fitting the outer tube to the outer periphery of the inner tube, as long as the outer tube can be attached to the outer periphery of the inner tube in some way. The outer tubes may be fastened together with rivets or the like, or the inner tube may be pushed into the outer tube to make them stick together.

[Function] The inner tube and outer tube, which are in close contact with each other, vibrate at their own vibration frequencies due to mechanical shock from the outside. However, since the inner and outer tubes have no integrity, they do not vibrate synchronously, and a deviation occurs in the vibrations at the contact surface between the inner and outer tubes. The damping composite metal plate tube of the present invention has no temperature dependence, the damping effect does not deteriorate even at high temperatures, and the damping effect does not deteriorate even at high temperatures. There is no need to consider sensitivity to

Furthermore, since the inner tube is a complete tube and no rivet holes or the like are drilled when the outer tube is brought into close contact with the inner tube, there is no fear that the fluid flowing inside the tube will leak.

Implementation rIA] Examples of the present invention will be described in detail to clarify the effects of the present invention.

1 to 5 show cross-sectional views of the first to fifth embodiments of the present invention. In the first embodiment, in FIG. 1, the inner tube 10 is made of a material of SS41 and a thickness of 3IA11 Then, this inner tube 10 was press-fitted into an outer tube 11 made of the same material by shrink-fitting and cooling, so that the outer tube 11 was tightly attached to the inner tube 10.

In the second embodiment, as shown in FIG. 2, an inner tube 10 is made of the same material and thickness as in the first embodiment, and this inner tube 10 has two semi-cylindrical outer tubes 12 and 31 made of the same material. 12 were sandwiched from above and below, and the flange portion 14 of the outer tube was fixed with a rivet 16, so that the outer tube 12 and 12 were closely attached to the inner tube 10.

In the third embodiment shown in FIG. 3, the inner tube 10 is exactly the same as that shown in FIG. The outer tube 13 is made of the same material and has a thickness of 3
Using one semicircular piece of IIIm, wrap the iron band 18 around the outer periphery of the inner tube 10 to tightly attach the outer tube 13 to the inner tube IO.

In the fourth embodiment, as shown in FIG. 4, the outer tube 12 is tightly attached to the inner tube 10 by a caulking portion 17 that wraps both ends of the outer tube 12 into the inner tube 10 made of the same material and thickness as in the previous embodiment. I forced it.

In the fifth embodiment, as shown in FIG. 5, two semi-cylindrical outer tubes 1212 are sandwiched and tightly attached to the same inner tube 10 as in the previous embodiment from above and below and joined by welding 15.

Next, in order to evaluate the damping properties of the first to fifth examples,
As shown in FIG. 6, the material to be measured 24 is fixed at two points on two threads 22 stretched between two plates 20, and
The attenuation waveform at the reception point S was measured using point H of No. 4 as the excitation point. The attenuation waveform was measured by amplifying the output from the sensor using an amplifier and outputting the waveform screen using a printer.

The obtained attenuation waveforms are shown in FIGS. 7 to 12, and FIG. 7 is a comparative example in which the material is 5S41, the inner diameter is 20, the wheel thickness is 3.
FIG. 8 shows the attenuation waveform of the integral tube of Theory II, FIG. 8 shows the first embodiment, FIG. 9 shows the second embodiment, and FIG. 10 shows the third embodiment.
FIG. 11 shows the attenuation waveform of the fourth embodiment, and FIG. 12 shows the attenuation waveform of the fifth embodiment.

As is clear from FIGS. 7 to 12, the first to fifth embodiments
In the example, the resonance frequency f measured from the zero-order damping waveform, which was found to have better damping characteristics than the comparative example, was set as the first
Shown in the table.

(Left space below) Table 1 Also, regarding the relationship between the measured vibration frequency and the time after excitation, in this example, the vibration suddenly attenuates at about 132 m5ec.

Next, the loss coefficient was calculated from the obtained attenuation waveform data. The loss coefficient was calculated by actually measuring the maximum amplitude A0 and measuring the amplitude An seconds after the maximum amplitude A0, using the following formula.

The calculation results of the loss factor are shown in FIG. 13 together with other materials. It is clear from FIG. 13 that the metal plate of this example exhibits a loss resistance comparable to that of the MII-Cu alloy.

[Effects of the Invention] The vibration-damping composite metal tube of the present invention is characterized by comprising an inner tube and an outer tube that covers at least half of the outer circumference of the inner tube and is in close contact with the inner tube. Since the inner tube and outer tube have no integrity with each other, they do not vibrate synchronously, and a deviation in vibration occurs at the contact surface between the inner tube and the outer tube. Therefore, the vibration of one tube is suppressed by the other tube at the contact surface, and is consumed as frictional energy, producing a damping effect.Therefore, there is no temperature dependence, and the damping performance does not deteriorate even at high temperatures, and there is no residual distortion. The present invention is a vibration-damping composite metal tube that is not affected by vibration, and can be provided with extremely excellent vibration-damping characteristics for industrial machinery, automobile parts, and the like. Further, since no rivet holes or the like are drilled in the inner tube when the outer tube is brought into close contact with the inner tube, the inner tube has excellent sealing performance.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the first embodiment of the present invention, FIG. 2 is a sectional view of the second embodiment, and FIG. 3 is a sectional view of the third embodiment of the present invention.
Fig. 4 is a cross-sectional view of the fourth embodiment of the present invention, Fig. 5 is a cross-sectional view of the fifth embodiment of the present invention, Fig. 6 is a perspective view explaining the vibration damping evaluation method, and Fig. 7 is a comparison. FIGS. 8 to 12 are diagrams showing the relationship between the attenuation waveform and time in the example. FIGS. 8 to 12 are diagrams showing the relationship between the attenuation waveform and time in the first to fifth embodiments. FIG. FIG. 3 is a diagram showing example loss coefficients. 10...Inner tube, (11,12,13)...Outer tube 2nd Figure 3 Figure 4 Figure 7 Figure 12 Figure 9 1312 "-11111 Aluminum

Claims (1)

[Claims] (1) A vibration-damping composite metal tube comprising an inner tube and an outer tube tightly attached to the inner tube so as to cover at least half of the outer circumference thereof.