JPH04147845A - Composite pipe of aluminum or aluminum alloy with oscillation-damping properties and its manufacture - Google Patents

Abstract

PURPOSE:To obtain an aluminum pipe with high oscillation reduction properties by constituting the pipe with an outer pipe and an inner pipe and allowing a resin layer with larger than a specified size of thickness to be present between the outer and the inner pipe. CONSTITUTION:A composite pipe of aluminum alloy is composed of an outer 1 and an inner pipe 2, and a resin layer 3 with a thickness of 10mum or larger is present between the outer pipe 1 and the inner pipe 2. The resin has generally oscillation damping properties. The composite pipe is superior in terms of oscillation damping properties. The recommended resins are, for example, polyurethane, polypropylene, polyethylene, etc., unless the resin layer is at least, 10mum or larger thick, adequate oscillation damping properties cannot be obtained. For the manufacture of the pipe, resin is coated on the outer surface of the inner pipe 2, while the outer pipe 1 is coated to obtain a composite pipe, and the tip of the composite pipe is spouted. Next, the spouted tip is held by tongs 4 through a die 5 and pulled out through the die 5 and a plug 6 so that the outer pipe, the resin layer and the inner pipe are combined in one piece. The composite pipe is superior in terms of size precision and surface accuracy and demonstrates aluminum properties.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention applies to aluminum or aluminum which has excellent vibration damping properties and is used in applications where vibrations are averse, such as the handles of lawn mowers and electric saws, the rollers of copying machines, and the pipes of automobiles. The present invention relates to an aluminum alloy composite tube and a method for manufacturing the same.

[Conventional technology]

Generally, Al1-Mn based 3003 alloy, Aj!
-Mg-3i based 6063 alloy, Aj! -Mg-based 50
Ai gold alloy such as 56 alloy is used. That is, 6063 alloy and 5056 alloy are used for the handles of lawn mowers and electric motors, which require high strength, and are tempered to near maximum strength through drawing and heat treatment.

Also, from the viewpoint of cutting workability, 300
3 alloy and 6063 alloy are used, and 3003 alloy and 6063 alloy are mainly used for automobile piping from the viewpoint of corrosion resistance.

By the way, when an object vibrates, the amplitude increases at a certain frequency (fr) called the resonance frequency (Figure 3).
, A is the maximum amplitude at the resonant frequency.

Then, the frequency that is 1/2 of this energy has an amplitude of As /12 (-3 dB in dB). This frequency width (half width, 3dB width) is Δ
When f is the loss coefficient (η), the loss coefficient (η) is expressed by the following equation.

η=Δf/fr A material with a large value of this loss coefficient η has excellent vibration damping properties, and vibrations are rapidly damped when external force is removed.

[Problem to be solved by the invention]

However, the above 3003 alloy, 6063 alloy, 5056
The loss coefficient of the alloy is less than 0.002, so it has poor vibration damping properties, and when used in the handles of lawn mowers and electric saws, the vibrations are easily transmitted to the hands, causing problems such as numbness in the hands when used continuously for a long time. be.

Copy machine rollers and automobile piping have similar problems in terms of vibration and noise.

Therefore, there is a strong desire to develop an aluminum tube that takes advantage of the characteristics of aluminum tubes, such as strength, corrosion resistance, and good dimensional accuracy, and that also has excellent vibration damping properties.

[Means for Solving the Problems] The present invention was developed as a result of intensive studies in view of the above situation, and the invention as claimed in claim 1 consists of an outer tube and an inner tube,
An aluminum or aluminum alloy composite tube with excellent vibration damping properties, characterized in that a tree yjFjJi with a thickness of 10μ or more is present between an outer tube and an inner tube, A control method characterized in that the outer surface of the tube is coated with a resin of a predetermined thickness, an outer tube is placed over it to form a composite tube, the tip of which is sealed, and then drawn through a die and a plug. This is a method for manufacturing aluminum or aluminum alloy composite tubes with excellent vibration properties.

Here, both the outer tube and the inner tube are of course made of aluminum or an aluminum alloy.

It is convenient for processing to make the outer tube and the inner tube the same material, but they may be made of different materials.

Further, the outer surface of the inner tube may be coated with resin by coating, or by covering it with a thin resin tube.

[Effect]

The structure of the aluminum or aluminum alloy composite tube of the present invention is shown in FIG.

In FIG. 1, 1 is an outer tube, 2 is an inner tube, and 3 is a resin layer.

Resin generally has vibration damping properties, so by having a resin layer between the outer tube and the inner tube, the composite tube of the present invention has much better vibration damping properties than conventional aluminum or aluminum single tubes. It will be excellent.

The resin may be any resin that can be easily applied or covered on the surface of the inner tube and has vibration damping properties, such as polyurethane, polypropylene, polyethylene, etc. The thickness of the resin layer is determined based on vibration damping properties, strength, etc., but sufficient vibration damping properties cannot be obtained unless the thickness is at least 10 mm or more.

Next, an example of the method for manufacturing the aluminum or aluminum alloy composite tube of the present invention is shown in FIG. 2.

In FIG. 2, 1 is an outer tube, 2 is an inner tube, 3 is a resin layer, 4 is a tongue, 5 is a die, 6 is a plug, and 7 is a plug rond.

The manufacturing method is to first coat the outer surface of the inner tube 2 with resin as shown in Figure 2A, and then cover the resin-coated inner tube 2 with the outer tube 1 to form a composite tube (Figure 2A). ). Next, seal the tip of this composite tube (Fig. 2 C), pass the tip through die 5, use tongs 4 to pull it out through die 5 and plug 6, and integrate the outer tube, resin layer, and inner tube. It is something to do.

The composite tube according to the present invention has good dimensional accuracy and surface accuracy, and can take advantage of the characteristics of aluminum to a far greater extent than a tube simply coated or covered with resin on an aluminum or aluminum alloy tube.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples.

Composite tubes having the configuration shown in Table 1 were manufactured. The manufacturing method is as follows. The inner tube is an aluminum alloy tube with an outer diameter of 25 mm and a wall thickness of 1 meter. After degreasing its surface, various resins are applied to the outer surface, and this inner tube is inserted into an outer tube with an outer diameter of 30 mm and a wall thickness of 1 meter. . The tip of this composite pipe was capped using a hydraulic capping machine, and drawn through a die with an opening diameter of 26 mm and a plug with an outer diameter of 22.3 ms. It is a composite pipe.

For comparison, various aluminum alloy pipes with an outer diameter of 30mm and a wall thickness of 2mm were fitted and drawn in the same manner as in the example, and the outer diameter was 26mm and the wall thickness was 1.8mm.
Obtained aluminum alloy single tube.

Test pieces with a length of 250 cm were cut from these pipes, and their vibration damping properties (loss coefficient η) were evaluated using the cantilever vibration method.

That is, one end of the test piece is chucked and random vibration is forcibly applied using an oscillator, and the vibration of the test piece is detected. The input/output amplitude ratio in the frequency domain of this input vibration and detected (output) vibration is determined by a two-channel fast Fourier transformer (2ch, FFT).

The resonance frequency (fr) showing the maximum amplitude ratio and the frequency width (Δf) that is 3 dB lower than the maximum amplitude ratio were measured, and the loss coefficient η was determined by the following equation.

η=Δf/fr The value of this loss coefficient η is also listed in Table 1.

As is clear from Table 1, the composite tube walls 1 to 5 according to the present invention have high loss coefficients of 0.059 to 0.095 and exhibit excellent vibration damping properties.

On the other hand, comparative example N in which the thickness of the resin layer is less than 10-
CL6 has a loss coefficient of 0.008, which is better than the conventional example, but does not have sufficient vibration damping properties.

Further, all of the conventional floors 7 to 10 have loss coefficients of less than 0.01, and have extremely poor vibration damping properties.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to obtain an aluminum or aluminum alloy composite tube having extremely excellent vibration damping properties, and it has a significant industrial effect.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the structure of the composite pipe of the present invention, FIG. 2 is an explanatory diagram showing the steps of the manufacturing method of the present invention, and FIG. 3 is a vibration resonance curve. 1...Outer tube, 2...Inner tube, 3...Resin layer, 4...
・Tongs, 5...Dice, 6...Plug, 7...
Plug Rondo. Patent applicant: Furukawa Aluminum Industry Co., Ltd.

Claims (1)

[Claims] 1) Consisting of an outer tube and an inner tube, with a thickness of 1 mm between the outer tube and the inner tube.
An aluminum or aluminum alloy composite tube with excellent vibration damping properties, characterized by the presence of a resin layer of 0 μm or more. 2) The outer surface of the inner tube is coated with resin to a predetermined thickness, and then the outer tube is placed on top of it to form a composite tube.The end of the tube is sealed, and then drawn through a die and a plug. A method for manufacturing aluminum or aluminum alloy composite pipes with excellent vibration damping properties.