JPS5848725B2 - Method for manufacturing turbine rotor using ceramic material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a turbine rotor for use in gas turbine engines, turbochargers, etc. using ceramic materials.

In recent years, with the progress of research and development of ceramic materials,
Turbine rotors are being made of ceramic.

As shown in FIG. 1, a method for manufacturing a turbine rotor using a ceramic material is to mold a turbine rotor body 1 and a shaft 2 separately, and to form a hole in the shaft center of the turbine rotor body 1 during greening or after preliminary sintering. A method has been proposed in which a turbine rotor shaft core portion 4 formed integrally with the shaft 2 is fitted onto the shaft 2, and then main sintering is performed to integrate the turbine rotor.

The shaft 2 may be used as it is to transmit rotation to the compressor impeller, or it may remain protruding from the back surface of the turbine rotor to some extent and be connected to another shaft.

Such a manufacturing method is described, for example, in JP-A-50-9530 or JP-A-52-102306.

However, according to such a conventional manufacturing method, when the shaft 2 is fitted, the fitting part on the turbine rotor main body 1 side, that is, the edge of the hole 3 widens, and the part A and further the part B as shown in FIG. V-shaped notch 5 as shown in the enlarged view of part A in Figure 1)
This will remain in the finished product.

Then, during operation, centrifugal stress concentrates on this portion, causing cracks and the like to occur in this portion, resulting in damage to the turbine rotor.

The present invention has been made by focusing on such conventional problems, and aims to solve the above problems by removing the notch that occurs at the edge of the fitting part by machining before or after sintering. It is an object.

Hereinafter, the manufacturing method according to the present invention will be explained based on the drawings.

Referring to FIG. 3, first, a turbine rotor body 1 and a shaft 2 are molded separately from a ceramic material (for example, silicon nitride or silicon carbide).

Here, the turbine rotor main body 1 is molded into a shape having a tapered hole 3 at its shaft core by, for example, injection molding or slip casting, and the shaft 2 has a tapered turbine rotor shaft core 4 at its end. It is molded into the desired shape by, for example, a hydrostatic press method.

In the figure, the shape during molding includes a smashing part.

Next, after sintering both of them together or temporarily sintering them, the turbine rotor shaft core part 4, which is integrally formed with the shaft 2, is inserted into the hole 3 of the turbine rotor body 1, and the conical surfaces are fitted together. let

At this time, the above-mentioned notch is formed at the edge of the fitting portion, that is, the A section and the B section.

After fitting, they are integrated by main sintering (for example, reaction sintering or pressureless sintering), but in the present invention, the turbine rotor main body 1 and the shaft core are separated before or after main sintering. The end face of No. 4 is cut by machining, and portion A and portion B where the notch occurs are removed.

Incidentally, the smashing part in the figure shows the part to be cut in this embodiment.

According to this manufacturing method, the finished product does not have any notches, so it does not have defects that could cause stress concentration and breakage of the rotor.

FIG. 4 shows another embodiment.

In this embodiment, the back surface of the turbine rotor is sloped during molding, thereby minimizing the removed part (smashing part in the figure) when removing part A, which is particularly prone to notches, and This is done in such a way that cost increases can be kept to a minimum.

Further, if a part of the finished product is sloped, there is an advantage that centrifugal stress can be reduced accordingly.

As explained above, according to the present invention, defects (notches) that occur between the turbine rotor body and the shaft during the manufacturing process.
Since the notches are removed by machining, it is possible to prevent excessive concentration of centrifugal stress during operation of the turbine rotor that would otherwise occur when notches exist, thereby increasing the strength of the turbine rotor and improving its durability.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a turbine rotor illustrating a conventional manufacturing method, FIG. 2 is an enlarged view of part A in FIG. 1, and FIG. 3 is a sectional view of a turbine rotor illustrating an embodiment of a manufacturing method according to the present invention. 4 are sectional views of a turbine rotor for explaining another embodiment. 1... Turbine rotor body, 2... Shaft, 3... Hole, 4... Turbine rotor shaft core, 5... Tsutsuchi.

Claims (1)

[Claims] 1. When manufacturing a turbine rotor from a ceramic material, the turbine rotor body and shaft are molded separately, and after fitting them together, the edges of the fitting part are removed by machining before or after sintering. A method for manufacturing a turbine rotor using a ceramic material, characterized in that: