JP2929064B2 - Damping steel pipe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a damping steel pipe.

[0002]

2. Description of the Related Art Metal pipes are widely used not only for industrial purposes but also as components of housing equipment and transporting machines. In general, the degree and form of vibration vary depending on the vibration source, but the metal pipe also vibrates and becomes a noise source.

[0003] In view of the above, various measures have been devised due to the recent tightening of regulations on environmental noise and an increase in consciousness. In particular, metal pipes include the following.

[0004] JP-A-57-53329 discloses that
At the time of forming the inner and outer tubes and the inner and outer tubes, a single material coil portion consisting of a non-metallic band coil provided at the portion where the intermediate layer is formed is unwound and subjected to an electric sewing tube to form a tube. After that, a continuous production method for a multilayer pipe is described in which a muffling function is imparted by passing through a roll straightening machine. Roll straightening reduces the tightness of the inner tube and outer tube, reduces the degree of adhesion, increases the degree of freedom of the wall where the inner tube and outer tube come into contact, and creates a friction phenomenon, thereby converting vibration energy into heat energy. A conversion silencing function is provided.

Japanese Unexamined Patent Publication No. 2-169121 discloses a vibration damping welded steel pipe using a vibration damping steel sheet as a material steel sheet.

[0006]

Although the above-mentioned damping steel pipe is excellent, it has a problem in characteristics of the damping steel pipe.

[0007] The steel pipe manufactured by the above method mainly exerts an effect on radiated sound, but is not so effective on mechanical vibration such as impact sound. That is, since the radiation sound is reduced by the gap between the inner tube and the outer tube, energy is less absorbed by vibration. In addition, since this steel pipe welds the inner pipe and the outer pipe simultaneously, there are many difficulties in the welding operation.

[0008] In the vibration damping welded steel pipe, the synthetic resin layer forming the intermediate material of the tubular vibration damping steel sheet is melted by the welding heat when welding the steel sheet ends, and generates a combustion gas to cause poor welding. As a result, there was a problem of reliability in the completed vibration-damping steel pipe.

[0009]

Means for Solving the Problems The present invention, among at damping steel metal for the outer tube forming strip consisting of an outer tube and inner tube which is formed into a circular, the outer tube and steel by welding a circular end The inner pipe is a damping steel pipe having a gap between circular ends .

[0010]

The present invention is based on the fact that when the outer tube is welded as usual and the inner tube is provided with a gap without welding the ends, the vibration damping performance becomes extremely good.

The provision of a gap between the circular ends of the inner tube provides excellent vibration damping performance because the inner tube is free from vibration of the outer tube, moves relatively to the outer tube, and reduces friction. It is presumed that this is because there is a sound deadening effect of converting vibration energy into heat energy. The length of the gap is preferably 0.5 mm to 20% of the inner circumference of the outer tube. 0.5mm
If it is less than this, the inner tube is welded by the weld bead of the outer tube, and the degree of freedom of the inner tube is deteriorated. Conversely, if it is wider than 20% of the inner circumference of the outer tube, there is a problem that directionality occurs in vibration damping properties and strength.

[0012] Then, the vibration damping steel pipe of the present invention will be described in detail with reference to FIG.

FIG. 1 shows a damping steel pipe 3 comprising an outer pipe 1 in which a metal band for forming an outer tube is formed in a circular shape and an inner tube 2 in which a metal band for forming an inner tube is formed in a circular shape. A gap 5 is provided between the circular ends 4 of the inner tube 2 .

In the damping steel pipe 3 shown in FIG. 1, the gap 5 is provided so that the inner pipe 2 can freely move with respect to the vibration of the outer pipe 1, and the vibration is generated by the friction between the outer pipe 1 and the inner pipe 2. Attenuates and improves damping performance .

[0015]

[Example] The material is ordinary steel, the outer tube thickness is 0.8 mm,
The thickness of the inner tube is 0.5 mm, the diameter of the outer tube is 25.4 mm,
A damping steel pipe of an example using a steel pipe having a length of 500 mm was manufactured. This damping steel pipe is supported by hanging it with a thread and struck with an impulse hammer to reduce the radiated sound pressure level from the pipe to 33.
The measurement was performed with a microphone fixed at a position of 0 mm. Table 1 shows the measurement results. As a comparative example, ordinary steel was used as the material, the outer diameter was 25.4 mm, the thickness was 1.6 mm, and the length was 500.
mm welded steel pipe was used. Welding strength was evaluated by an adhesion flatness test with the seam part right beside.

[0016]

[Table 1]

In the embodiment, the vibration damping performance is 14 times higher than that of the comparative example.
A remarkable effect of dB was obtained, and a steel pipe was obtained in which the welding strength was flattened to the close contact and no defects appeared.

[0018]

According to the present invention, a damping steel pipe having very good damping performance and excellent welding strength can be obtained, and the effect is extremely large.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a damping steel pipe having a gap in an inner pipe according to the present invention .

[Explanation of symbols]

1 the outer tubular second tube 3 damping steel 4 rounded end 5 gap between

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-185140 (JP, A) JP-B Hei 1-28700 (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) B21C 37/06 B32B 15/08

Claims (1)

(57) [Claims] 1. A damping steel pipe composed of an outer pipe and an inner pipe in which a metal band for forming an inner pipe and an outer pipe is formed in a circular shape, wherein the outer pipe is formed by welding a circular end to a steel pipe, and the inner pipe is formed between the circular ends. Damping steel pipe with a gap in it .