JPH048630B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for manufacturing an impeller, which is one of the main parts of turbo fluid machines such as compressors, blowers, fans, and pumps. This relates to the manufacturing method of impellers.

[Conventional technology]

The structure of the impeller is shown in Figure 1. Figure 1 -
A line arrow view is shown in Fig. 2. Impellers can be manufactured using methods such as welding, casting, and electrical discharge machining, but casting has limitations in terms of strength because the manufacturing cost of the mold is high and casting defects are inevitable. In addition, electric discharge machining requires a very long machining time and there are restrictions on the direction of movement of the electrode, so there are restrictions on the shape of the flow path of the impeller.
For this reason, impeller manufacturing methods by welding, which are not limited by the flow path shape and are relatively inexpensive to manufacture, have been widely adopted.

The structure of a conventional welded impeller will be explained with reference to FIGS. 1 and 2. The core plate 1, the side plates 2, and the blades 3 are each formed into an integral structure by welding the core plate 1 and the blades 3 together, or the side plates 2 and the blades 3 together. Figure 2 shows the condition of the weld bead. The welding work and the finishing work of the weld bead 4 are performed by inserting a welding rod or a cutter from the exit of the blade 3, except for the tip of the entrance of the blade 3. X and Y indicated by dashed dotted lines indicate the inserted state of the welding rod or cutter. Second
The exit angle β of the blade shown in the figure is one of the factors that affects the fluid performance of the impeller. In the conventional welded impeller, the value of β is relatively large, and the welding rod is at the entrance of the blade as shown in the figure. It was easy to reach the tip and there was no problem with welding and bead finishing work. In this figure, 5 is a blade inlet, and 6 is a blade outlet.

[Problem to be solved by the invention]

On the other hand, it has been known that for an impeller that handles a small flow rate, the fluid performance is improved by decreasing the value of the outlet angle β, but in this case, the cross-sectional shape of the impeller is as shown in Figure 3. Since α becomes smaller, the length of the blade becomes longer when the impeller has the same outer diameter. For this reason, when trying to manufacture an impeller by welding, the welding rods are placed in the X and Y positions, so the area between A and B on the inlet side of the blade becomes a blind spot as shown in the figure, and the welding work and bead finishing are difficult. I can't work. Therefore, it has not been possible to manufacture an impeller with a small exit angle β using the conventional welding method.

An object of the present invention is to obtain a manufacturing method of a welded impeller that can obtain high fluid performance without being restricted by the flow path shape of the impeller even if the impeller has a small exit angle of the blades and handles a small flow rate. be.

[Means to solve the problem]

To achieve the above object, the present invention provides an impeller manufactured by integrally constructing a core plate, a side plate, and a blade by welding, in which the side plate is divided into at least two concentric circular pieces in the radial direction. At the same time, the blades also have at least two holes in the longitudinal direction.
The blade pieces divided into the above are manufactured. First, the inner diameter side blade piece is welded to the core plate, the inner diameter side side plate piece is welded to the inner diameter side blade piece, and then the outer diameter side blade piece is welded to the inner diameter side blade piece. The core plate and the inner blade piece are welded, and finally the outer side plate piece is welded to the inner diameter side plate piece and the outer diameter side blade piece.

[Effect]

According to the present invention, by having the above configuration,
When welding an impeller, it is possible to eliminate the blind spot of the welding rod, so welding and bead finishing work can be easily performed even when manufacturing an impeller with a small exit angle and a long blade length. becomes possible.

〔Example〕

In conventional manufacturing methods, when manufacturing an impeller with a small exit angle, that is, a long blade length, by welding, welding is impossible because a blind spot is created on the blade inlet side for welding work and bead finishing work. In the present invention,
In order to eliminate this blind spot, the impeller is manufactured by dividing the blades and side plates or core plate, and sequentially joining each piece by welding.

A specific embodiment of the present invention will be described below in Figures 4 to 7.
This will be explained using figures. This example shows a manufacturing method in which the side plate and the blade are divided into two parts.

The side plate 2 is divided into two parts near the middle between the blade inlet 5 and the outlet 6 into an inner diameter side plate piece 2a and an outer diameter side plate piece 2b,
In addition, the blade 3 is connected to the inner diameter side blade piece 3a and the outer diameter side blade piece 3.
Divide into two parts.

The manufacturing procedure is to first weld the blade 3a to the core plate 1 as shown in Figure 4, and then attach the side plate piece 2 to this blade piece 3a.
Weld a. FIG. 5 shows a view taken along the - line in FIG. 4. In this state, the length of the blade 3 is about half of the total length, so the welding rod is positioned at the X and Y positions indicated by the dashed line, and welding can be performed up to the tip on the blade inlet 5 side. After welding in this state, the weld bead 4 is finished and non-destructively inspected.

The next manufacturing steps are shown in Figures 6 and 7. First, the blade piece 3b is welded to the core plate 1, and the blade piece 3b is welded to the core plate 1.
A and blade piece 3b are welded together. After welding bead formation and non-destructive testing, the side plate pieces 2a and 2b are welded together, and then the blade pieces 3b and side plate pieces 2b are welded together. In this case, the position of the welding rod is at the X and Y positions shown by the dashed line in Fig. 7, so
All parts to be welded can be welded. next,
Blade piece 3b and side plate piece 2b, side plate piece 2a and side plate piece 2
The entire welding work is completed by finishing the bead of the weld with b and performing a non-destructive inspection.

The above manufacturing steps are summarized as follows.

Welding of the core plate 1 and the blade piece 3a Welding of the blade piece 3a and the side plate piece 2a, Bead finishing and inspection of the welded part Welding of the core plate 1 and the blade piece 3b Welding of the blade piece 3a and the blade piece 3b, Welding Welding of the side plate piece 2a and the side plate piece 2b Welding of the side plate piece 2a and the blade piece 3b Bead finishing and inspection of the welded part As explained above, according to this embodiment, welding work, It becomes possible to completely weld without creating a blind spot during bead finishing work, and it is also possible to completely manufacture impellers with small exit angles, that is, long blade lengths, by welding.

Therefore, as with conventional manufacturing methods, there are restrictions on the flow path shape of the impeller (in the case of electric discharge machining),
There are no restrictions on strength (in the case of casting), and an impeller with good fluid performance can be obtained at low cost.

〔Effect of the invention〕

According to the present invention, even if the impeller has a small exit angle and handles a small flow rate, it can be manufactured completely by welding without being restricted by the flow path shape of the impeller, and has high fluid performance. This has the effect of making it possible to produce a welded impeller.

[Brief explanation of drawings]

Figures 1 and 2 are diagrams showing the structure and manufacturing method of a conventional impeller; Figure 1 is a longitudinal cross-sectional view of the impeller;
Figure 2 is a view taken along the - line arrow in Figure 1, Figure 3 is a diagram showing the structure of the impeller when the blade exit angle is small, and Figures 4 to 7 are views corresponding to Figure 2. 4 and 6 are longitudinal cross-sectional views of the impeller;
Fig. 5 is a view taken along the line V-V in Fig. 4, and Fig. 7 is a view taken along the line V-V in Fig. 4.
It is a - line arrow view of a figure. 1... core board, 2... side plate, 2a, 2b... side plate piece, 3... blade, 3a, 3b... blade piece, 4...
Welding bead, 5...blade inlet, 6...blade outlet.

Claims (1)

[Claims] 1. In an impeller manufactured by integrally constructing a core plate, side plates, and blades by welding, the side plate is manufactured into at least two or more concentric side plate pieces divided in the radial direction, and the blades are also longitudinally divided. The blade piece is divided into at least two parts in the direction, and after welding the inner diameter side blade piece to the core plate,
The inner diameter side plate piece is welded to the inner diameter side blade piece, then the outer diameter side blade piece is welded to the core plate and the inner diameter side blade piece, and finally the outer diameter side side plate piece is welded to the inner diameter side side plate. A method for manufacturing a welded impeller, characterized by welding to the blade pieces and the outer diameter side blade pieces.