JPH01321014A - Manufacture of high damping pipe - Google Patents

Abstract

PURPOSE:To improve the strength of the high damping pipe and to prevent deterioration of the noise absorbing property by heating to fluidize a synthetic resin drawn out between a metallic pipe and a large diameter metallic pipe with larger diameter than said pipe through cold drawing. CONSTITUTION:A synthetic resin tape 3 consisting of a viscoelastic molecular resin in wound spirally on the periphery of the seamless steel inner pipe 1 to perfectly coat this periphery. This steel inner pipe 1 wound with this synthetic resin tape 3 is inserted into the seamless steel outer pipe 2 having larger diameter than the steel inner pipe 1 to make a duplex steel pipe 4. One end side of this duplex steel pipe 4 is drawn to make mouthed part. A plug 5 is stored inside the duplex steel pipe 4 and its drawn mouthed part is drawn through a drawing die 6. The duplex steel pipe 4a manufactured through drawing in such a manner is heated to nearly 200 deg.C using a thermal insulating furnace. After fluidizing the synthetic resin layer 3a between the duplex steel pipe 4a, this synthetic resin layer 3a is solidified. Therefore, its strength is improved and without deteriorating the noise absorbing property, extremely superior and useful high damping pipe is enabled manufacturing.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method of manufacturing a damping pipe.

[Conventional technology]

As is well known, metal tubes are widely used as components of machines, equipment, and the like.

By the way, since machines, equipment, etc. generally generate vibrations during operation, the degree of vibration varies depending on the supporting conditions, length, diameter, wall thickness, etc., but this metal pipe also vibrates and becomes a source of noise. On the other hand, in recent years, regulations regarding environmental noise have become stricter from the perspective of occupational safety and health to protect workers from noise that is harmful to their health, and numerous measures have been taken to suppress noise generated from machinery, equipment, etc. It is being done.

Methods for preventing noise caused by the vibrations of metal pipes in machinery, equipment, etc. as described above include: 1) Covering the metal pipes with sound insulating material.

■ Shift the resonant frequency position of the metal tube by changing the support conditions.

■ A damping pipe with synthetic resin interposed between the inner and outer pipes is used.

The following methods were adopted.

The above noise prevention method (■) has the problem that the sound insulation material enclosing the metal pipe interferes with the vibration of the metal pipe, causing peeling, abrasion, etc., and its lifespan is short. Since the resonant frequency position differs due to slight structural differences in machines, equipment, etc., the method of supporting it, etc. must be changed depending on the situation after confirming the resonant position. While there is a problem that it is not necessarily practical, the noise prevention method described in (■) above reduces the noise generated by vibration.
This is preferable because it is absorbed by the synthetic resin layer between the metal inner tube and the metal outer tube before it propagates into the air, and has excellent durability.

In this way, it is preferable to adopt vibration damping pipes for machines, equipment, etc. in order to prevent noise from machines, installations, etc., so for example, damping pipes are formed into a cylindrical shape by press bending, and the opposing end surfaces are There was an example of using a damping pipe made by welding.

[Problem to be solved by the invention]

Although the damping pipe manufactured by the manufacturing method described above is excellent in its own way, the heat generated during welding has caused problems in the quality of the damping pipe as described below.

In other words, the synthetic resin layer between the cylindrical damping steel plates melts due to the welding heat and generates combustion gas, making welding difficult. There was a problem with reliability.

In addition, as mentioned above, the quality of this synthetic resin layer changes due to the welding heat during welding, and the joint-U portions may not match, resulting in break points in this synthetic resin layer, which can cause vibrations in the finished vibration damping pipe. Another problem has arisen in that the absorption performance deteriorates.

Therefore, an object of the present invention is to provide a method for manufacturing a vibration damping pipe that has excellent strength and does not deteriorate noise absorption performance by utilizing a technology for manufacturing multiple cladding pipes.

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned problems. Therefore, the gist of the method for manufacturing a damping pipe according to the present invention is to coat a synthetic resin on the outer periphery. After cold-drawing the multiple tubes made by inserting the metal tube into a large-diameter metal tube with a larger diameter than the metal tube, the synthetic resin layer made of synthetic resin between the two tubes is heated until it becomes fluidized. It is characterized by

[Effect]

In the present invention, the manufacturing method of the damping pipe is as described above, so that the synthetic resin tape between the metal pipe and the large-diameter metal pipe having a larger diameter than the metal pipe is pulled out by cold drawing and becomes a long pipe. It follows and is stretched thinly. By heating this stretched synthetic resin to the point where it becomes fluidized, all the gaps between the cold drawn metal tubes are filled with a synthetic resin layer that has hardened after flowing, and there are no break points in this synthetic resin layer. will not occur.

Furthermore, since the heating temperature is at a level that fluidizes the synthetic resin, the synthetic resin layer does not change in quality or gas is generated from the synthetic resin layer.

〔Example〕

The manufacturing method of the damping pipe according to the present invention will be explained below based on Fig. 1, which is an explanatory diagram of coating the steel inner pipe with synthetic wood + 1t't, and Fig. 2, which is an explanatory diagram of the damping pipe being pulled out. do.

■ First step (Figure 1): Wrap a synthetic resin tape (3) made of viscoelastic polymer resin in a spiral around the outer periphery of the seamless steel inner tube (+) so as to completely cover the outer periphery. do.

■ Second step (Fig. 1): The seamless steel outer tube (2) with a larger diameter than the steel inner tube (1) around which this synthetic resin tape (3) is wound
) to form a double steel pipe (4).

■ Third process: This double steel pipe (4
) Squeeze one end and kiss.

■Fourth step (Fig. 2): The plug (5) is housed inside this double steel pipe (4), and its narrowed mouth is pulled out and passed through a die (6).
Pull it out as you normally would.

■ Fifth step: The double steel pipe (4a
) is heated at approximately 250°C using a heat retention furnace (not shown) to form a synthetic resin layer (3a) between the double steel pipes (4a).
After fluidizing, this synthetic resin layer (3a) is solidified.

Incidentally, Table 1 shows the specifications of the damping pipe manufactured through the above manufacturing process.

(Hereinafter, blank spaces) Table 1, Specifications of steel pipes and damping pipes (unit: mm) The damping pipes manufactured in this way using each τJ method described in Table 1 above, and the damping of each of these dimensions. By comparing the pipes with existing steel pipes of the same size, it was confirmed that each of the vibration damping pipes had excellent noise absorption performance, and since the thickness of the synthetic resin layer was thin, the strength was improved. It was confirmed that there were no problems at all.

In this example, a synthetic resin tape was wound around the outer peripheral surface of the steel inner tube (1), but instead of wrapping a synthetic resin tape, a paste-like synthetic resin was wound inside the steel tube. Even if the coating is applied to the outer circumferential surface of the pipe (1), the steel inner pipe (]) is inserted into the steel outer pipe (2), and cold drawing is performed, the manufacturing method of this embodiment can be applied. It is possible to manufacture a vibration damping pipe that has the same noise absorption performance as the vibration damping pipe that has been developed.

Furthermore, as the material for the synthetic resin tape used in the manufacture of vibration damping pipes, it is sufficient to use synthetic resins that are used in well-known vibration damping steel plates, such as "chloride/vinyl resin", "vinyl/vinyl resin", etc. Acetal resin,
There is no problem at all if it is a phenolic resin or the like (therefore, it is not limited to the synthetic resin material itself).

Further, in this example, seamless steel pipes were used as both the inner and outer steel pipes, but it is also possible to manufacture vibration-damping steel pipes having equivalent noise absorption performance even if non-seamless electric hYwJ pipes are used.

However, as mentioned above? When using a 1t FIIa tube, a synthetic resin tape is wrapped around its outer circumferential surface,
Alternatively, before pushing an ERW inner steel pipe whose outer circumferential surface is coated with a paste-like resin into an ERW steel pipe, it is necessary to check the "sag" that occurs during ERW at the welded part inside the ERW steel pipe. ,
It is necessary to remove "unevenness" etc. in advance.

Further, in this embodiment, an example of manufacturing a damping pipe made of double steel pipes has been described, but this manufacturing method can also be applied to other metal pipes made of materials other than steel bases.

Further, in this example, heat treatment was performed after cold drawing, but technically it is considered possible to draw the double steel pipe while heating it.

However, when drawing such double-walled steel pipes, the drawing die is usually cooled to prevent wear, so drawing it out while heating it (which not only causes severe wear on the drawing die but also reduces long-term damage) From this point of view, this is not necessarily a good idea as it may cause problems such as the accuracy of the outer diameter of the drawn product, the so-called damping pipe, or running costs.

〔Effect of the invention〕

In the present invention, the damping pipe is made by cold drawing a multi-layered pipe in which a metal inner tube whose outer periphery is coated with a synthetic resin is inserted into a metal outer tube having a larger diameter than the metal inner tube, and then the synthetic resin flows. They were able to manufacture vibration-damping pipes by heating the material until it became oxidized.

Therefore, since the method for manufacturing a vibration damping pipe according to the present invention uses a pre-manufactured pipe, the synthetic resin layer may be deteriorated by the welding heat during welding, as in the case of manufacturing a conventional vibration damping pipe. Not only does it eliminate the occurrence of break points or the combustion of this synthetic resin layer and generate combustion gas, but it also provides reliable strength and exhibits the desired noise absorption performance. It is now possible to manufacture damping pipes.

Furthermore, by using this damping pipe, there is no need for special structural considerations for noise prevention, and economical effects have also been produced, such as making it possible to simplify the structure of machines and equipment.

Therefore, the present invention provides an extremely excellent and useful vibration damping pipe with excellent strength and no deterioration in noise absorption performance! We were able to establish a method for

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of coating a metal tube with synthetic resin, and FIG. 2 is an explanatory diagram of a state in which multiple tubes are pulled out. (+1---1 steel inner tube, (2)---1 steel outer tube, (3)
--- One synthetic resin tape, (3a) --- One synthetic resin layer, (4) --- Double steel pipe, (4a) --- One Double steel pipe after drawing, (5) --- -Plug, (6)---
One draw die. Patent Applicant Kobe Steel Corporation Representative Patent Attorney Akira Kanamaru - Figure 2

Claims (1)

[Claims] (1) After cold drawing a multi-layered tube made by inserting a metal tube whose outer periphery is coated with a synthetic resin into a large-diameter metal tube with a larger diameter than the metal tube, a composite tube made of synthetic resin is formed between the two tubes. A method for manufacturing a vibration damping pipe, which comprises heating the resin layer until it becomes fluidized.