JPH0544692A - Manufacture of centrifugal impeller - Google Patents

Abstract

PURPOSE:To surely prevent the generation of notch by perfectly electron-beam- welding the whole surface of the contact part between a blade and a main plate. CONSTITUTION:A main plate 11 is divided into a main shaft fitting part 12 and a disc part 13. The disc part 13 of the main plate 11 is abutted to the side surface part of a blade 15 cut out from a front plate 14, and electron beam welding is executed as shown by the mark D over the whole length in the longitudinal direction of the blade 15, along the curvature of the blade 15, and the electron beam welding is executed up to the inside diameter part edge part of the disc part 13. After the electran beam welded part at the inside diameter side edge part of the disc part 13 is finishing-worked, the whole peripheries the disc part 13 and the main shaft fitting part 12 are joined through the electron beam welding as shown by the mark E.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a centrifugal impeller by electron beam welding or the like.

[0002]

2. Description of the Related Art As shown in FIG. 4, the structure of a centrifugal impeller includes a disc called a front plate 1 located on the fluid inlet side of the impeller, and a plurality of curved vanes 2 disposed on the front plate 1. And a circular plate called a main plate 3 connected to each other. When the fluid passes from the inner diameter side to the outer diameter side of the impeller as shown by an arrow A, it is given kinetic energy to be boosted in pressure. It is like this.

In the conventional method of manufacturing such a centrifugal impeller, studs are cut out from the blades in a 100-foot shape, holes are formed in the front plate 1 and the main plate 3 to match the studs, and both plates 1 are made. ，
A method has been adopted in which both plates 1 and 3 and the blade 2 are integrally formed by driving in from the outside of 3.

However, in recent years, the manufacturing method by welding has been widely used due to the progress of welding technology and the superiority in strength. Further, electron beam welding is adopted from among various welding techniques for welding the impeller. Electron beam welding is a method in which a sample is irradiated with a high-speed electron beam in a high vacuum and the impact heat is used to perform welding. Since this welding method is performed in a high vacuum, materials that easily react to the atmosphere can be easily welded.Because the electron beam can be narrowed down by the lens to concentrate the energy, it is possible to weld high melting point materials and arc welding. Compared with this, it is characterized by deep penetration and the ability to concentrate heat.

Particularly for centrifugal impellers, since the penetration is deep and the conventional multi-layer welding is used, electron beam welding enables more rapid welding and the beam output can be accurately controlled. Wide range of welding is possible up to thick plates. Electron beam welding can be said to be an optimal welding method because it can perform welding of small items with high precision and finishing accuracy.

In the conventional method for manufacturing a centrifugal impeller by electron beam welding, as shown in FIG. 5, blades 2 are integrally machined from a front plate 1, and a main plate 3 is brought into contact with a side surface of the blades 2 and the main plate 3 is abutted. Welding is performed from the backside of No. 3 by electron beam welding while making a molten pool along the bend of the blade 2. That is, in FIG. 5, the portion indicated by the cross-hatched line B is the welding location where electron beam welding has been performed.

[0007]

However, according to the conventional method for manufacturing the centrifugal impeller by electron beam welding described above, since the side on which the electron beam welding is performed is the main plate 3, the total length of the blade 2 in the longitudinal direction is large. When electron beam welding is performed over the entire area, radial beam marks are left on the main plate 3, and it is difficult to finish this from the fluid passage side of the impeller.

For this reason, electron beam welding is not performed up to the end surface of the blade 2 on the small diameter side in the longitudinal direction, and a portion C in which the blade 2 and the main plate 3 are still in contact is left. As a result, there is a problem that a notch is generated at the boundary of the relevant portion and reliability in strength in a high stress field is poor.

The present invention has been made in order to solve the problems of the prior art as described above, and it is possible to completely prevent the occurrence of notches by completely electron beam welding the contact portions between the blades and the main plate. An object of the present invention is to provide a method for manufacturing the centrifugal impeller.

[0010]

In order to solve the above-mentioned problems, the present invention divides the main plate of a centrifugal impeller into a main shaft fitting part and a disk part which abuts against the side surface of the vane and scrapes it from the front plate. The side surface of the vane is brought into contact with the disc portion, and the entire length in the longitudinal direction of the vane is electron-beam welded from the back surface of the main plate along the bending of the vane. The part and the part are electron beam welded.

[0011]

According to the above means, the main plate of the centrifugal impeller is divided into the main shaft fitting part and the disc part, so that the entire length in the longitudinal direction can be extended along the bending of the side faces of the disc part and the front plate blade. Electron beam welding can be performed, and the end portion of the electron beam welding portion other than the abutting portion of the blade on the inner diameter side of the disk can also be finished. Therefore, if the main shaft fitting portion and the disk portion of the main plate are thereafter joined by electron beam welding, there will be no portion left unelectron beam welded at the main plate contacting portion of the blade, and no notch will be generated.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a sectional view showing an example of a centrifugal impeller manufactured by the method of the present invention. In FIG. 1, according to the method of the present invention, the main plate 11 of the centrifugal impeller is divided into a main shaft fitting part 12 and a disc part 13. The main plate 11 is attached to the side surface of the blade 15 carved from the front plate 14.
13 is abutted, and in this state, electron beam welding is performed along the bending of the blade 15 over the entire length in the longitudinal direction of the blade 15 as indicated by the cross hatched line D. It reaches the inner diameter side end of the portion 13. Therefore, unlike the conventional electron beam welding shown in FIG. 5, it is possible to eliminate the portion C between the blade 2 and the main plate 3 where the electron beam welding is not performed.

Further, according to the method of the present invention, the disc portion 1
After finishing the electron beam welding portion at the inner diameter side end of 3, the portion indicated by E between the disk portion 13 and the spindle fitting portion 12 is welded along the entire circumference by electron beam welding.

FIG. 2 is a plan view of the main plate 11 in FIG. 1 viewed from the back side. As shown in detail in this FIG.
Electron beam welding is performed along the bending of the blade 15 as shown by the symbol D in the entire length of the blade 15 in the longitudinal direction and a part on the inner diameter side of the disc portion 13. After this, the disc portion 13 and the spindle are fitted. The entire circumference is joined to the insert portion 12 by electron beam welding indicated by the symbol E.

FIG. 3 is a sectional view taken along the line III-III in FIG. 2, in which the main plate 1 is attached to the blade 15 cut out from the front plate 14.
1 shows a state in which electron beam welding is performed as indicated by the reference numeral D with the disk portion 13 of No. 1 abutting.

[0017]

As described above, according to the present invention, the electron beam welding is performed over the entire length of the blade in the longitudinal direction without leaving a portion where the electron beam welding is not performed in the contact portion between the blade and the main plate in the centrifugal impeller. Therefore, there is no concern that a notch will occur as in the conventional case. Further, by dividing the main plate into the main shaft fitting portion and the disc portion, it is possible to finish the electron beam welding portion other than the contact portion of the blade of the disc portion. Therefore, according to the present invention, there is an excellent effect that the reliability in strength of the centrifugal impeller can be increased in a high stress field.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a centrifugal impeller manufactured by the method of the present invention.

FIG. 2 is a plan view of the main plate in FIG. 1 viewed from the back side.

FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a sectional view showing a centrifugal impeller manufactured by a conventional method.

FIG. 5 is a sectional view showing a centrifugal impeller manufactured by another conventional method.

[Explanation of symbols]

 11 Main Plate 12 Spindle Fitting Part 13 Disc Part 14 Front Plate 15 Blade D Electron Beam Welding Part E Electron Beam Welding Part

Claims (1)

[Claims] Claim: What is claimed is: 1. A centrifugal impeller main plate is divided into a main shaft fitting portion and a disk portion that abuts on the side surface of the blade, and the side surface of the blade carved from the front plate and the disk portion are brought into contact with each other, A centrifugal blade characterized in that the entire length in the longitudinal direction of the blade is electron beam welded from the back surface of the main plate along the curve of the blade, and then the main shaft fitting portion and the disc portion of the main plate are electron beam welded. Car manufacturing method.