JPH10317906A - Method for replacing rotor blade of rotor with integral blade - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for easily replacing a rotor blade of a rotor with an integral blade. SOLUTION: In a method for replacing a rotor blade 14 of a rotor 10 with an integral blade having a disk 12, the rotor blade 14 is detached in such a manner as to leave a blade stub portion 15 extending outward from the disk 12 and having a front edge, a rear edge, a suction part and a pressure part. Subsequently, a collar 24 having a hollow portion for receiving the blade stub portion 15 is prepared, and further, the blade stub portion 15 is contained inside the hollow portion of the collar 24, so that the collar 24 is connected to the blade stub portion 15. Consequently, a platform is formed of the blade stub portion 15 and the collar 24. Finally, another rotor blade to be replaced is connected to the platform.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to rotors with integral blades for gas turbine engines and, more particularly, to a method of making or repairing a rotor with integral blades.

[0002]

BACKGROUND OF THE INVENTION The compressor and turbine sections of a gas turbine engine typically include a plurality of rotor assemblies and vane assemblies. The rotor assembly is designed to provide work to the center gas passing through the compressor section and to extract work from the center gas passing through the turbine section. The stator vane assembly helps direct the center gas into and out of the rotor assembly, thereby increasing the efficiency of the engine.

[0003] Each rotor assembly includes a disk and a plurality of blades mounted on the disk, the blades being equally distributed around the circumference of the disk. Historically, the blades have been attached to the disk by mechanical means, such as, for example, a "Christmas tree" type attachment means, in which a Christmas tree shaped blade root is attached to the disk. Accepted by a combination bud. The advantage of mechanically attaching the blade in this manner is that the blade can be easily replaced if the blade is damaged or a defect is discovered. The disadvantages of mechanically mounting the rotor blades, however, are that the rotor disk must be large enough to accommodate all the blade roots of the rotor assembly, and the considerable stress created by the mechanical mounting means. There are things you need to be able to withstand. Another disadvantage of rotor assemblies with mechanically mounted blades is the weight of the rotor assembly. That is, in many mechanical mounting configurations, the disk must be larger than would otherwise be required to accommodate the blade root. The additional weight of such a large disk and the hardware required to secure the blades to the disk undesirably increases the weight of the rotor assembly.

[0004] Thus, rotors with integral blades eliminate many of the above-mentioned disadvantages of rotor assemblies that use a mechanical mounting arrangement. That is, in rotors with integral blades, the blades are metal bonded to the disk. This metallurgical connection eliminates the need for mounting hardware and the associated weight. Metal bonding of the blades also allows the rotor disk to be smaller and therefore lighter to use as compared to a rotor assembly having a mechanical mounting configuration.

[0005] A disadvantage of rotors with integral blades, however, is that blades mounted by metal bonding cannot be replaced by simple methods such as sliding the blades into and out of the disc recess. Those skilled in the art will recognize that rotors with integral blades are expensive and that some percentage of the integral blades of the rotor are fabricated with unacceptable defects and / or are subject to "foreign matter damage" during operation. Let's do it. In each case, one or more blades need to be replaced to ensure the integrity of the rotor with integral blades and to avoid wasting expensive parts.

[0006] From the foregoing, there is a need for a method by which a rotor blade can be attached to a rotor disk with an integral blade for the purpose of making or repairing the rotor with the integral blade.

[0007]

DISCLOSURE OF THE INVENTION The present invention has been made in response to such a demand. Accordingly, it is an object of the present invention to provide a method by which a rotor blade can be attached to a rotor with an integral blade.

Another object of the present invention is to provide a method by which a rotor with integral blades can be repaired to replace a rotor blade.

According to the present invention, there is provided a method for replacing a rotor blade of a rotor with an integral blade having a disk, comprising the steps of: (a) extending outward from the disk to form a leading edge and a trailing edge; So as to leave a blade stub portion having a suction side and a pressure side,
Removing the rotor blades; (b) providing a collar having a hollow portion for receiving the blade stub portion; (c) placing the blade stub portion within the hollow portion of the collar; (d). Coupling the collar to the blade stub portion to form a platform with the blade stub portion and the collar; and (e) coupling a replacement rotor blade to the platform. Method for replacing a rotating rotor blade.

[0010] An advantage of the present invention described above is that a method of attaching a rotor blade to a rotor with an integral blade is provided.
A method is provided that can be used to repair a rotor with an integral blade that is already in service, or that can be used as a method of initially installing a rotor blade.

Another advantage of the present invention is that it provides a method of repairing a rotor with integral blades that minimizes mechanical deformation of the rotor blade stub.
That is, under some conventional replacement blade mounting methods, the rotor blade stub must be exposed to a significant amount of thermal energy before mounting the replacement blade. As a result, the stub deforms mechanically, especially around the leading and trailing edges. In contrast, the present invention provides support along the leading and trailing edges with a collar,
This eliminates unwanted deformation.

Yet another advantage of the present invention is that various metal bond mounting methods can be used to mount the replacement blade to the rotor blade stub. That is, the present invention provides an idea of a platform on which a replacement blade can be mounted. This platform provides increased surface area and facilitates metal bonding.

The foregoing objects, features and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments of the present invention with reference to the accompanying drawings.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a part of a rotor 10 with an integral blade
2, the disk having a plurality of blades 14 and blade stubs 15 extending radially outward from the disk 12. Each of the blades 14 is metal bonded to the disk 12. And each blade 14 has a leading edge 2
0 and trailing edge 22.

Referring now to FIG. 3, the collar 24 includes an inner radial surface 26, an outer radial surface 28, and a hollow portion 3 extending between the inner and outer radial surfaces 26 and 28.
0, and die side surface 32. The geometry of the hollow section 30 is substantially equal to the geometry of the blade stub 15, ie, the hollow section 30 and the blade stub 1
5 form a mating pair. The collar 24 is made of substantially the same material as the material of the integral blade stub 15, and is in a heat treatment state similar to the heat treatment state of the integral blade stub 15. According to the preferred embodiment, the collar 24 is divided into two halves.

Referring now to FIG. 4, the blade repair die 34 includes a pair of halves 35, each of which
5 has a recess 36 for receiving a portion of the collar 24. The recess 36 and a portion of the collar 24 received within the recess 36 form a mating pair. Guide pins 37 are used to position the two die halves 35 with respect to each other. According to a preferred embodiment, the biasing means 38 includes a pair of hydraulic cylinders 40. However, alternatively, other mechanical means can be used.

Referring now to FIG. 2, according to the present invention,
The rotor with integral blades 10 having a damaged or defective rotor blade 14
4 is repaired by replacing it with a replacement blade 42 (see FIG. 5). That is, the first stage of repair is
The removal of the damaged or defective rotor blade 14 from the disk 12 leaving a portion of the damaged or defective rotor blade 14 extending out of the disk 12, the blade stub 15. Blade stub 15
The desired height depends on the specific individual application. For example, factors such as the original height of the rotor blade 14 to be repaired, the size of the blade repair die 34 and the state of damage or defect may affect the desired height of the blade stub 15. Next, debris or oxide formed on the surface to be bonded is degreased, grid sprayed,
The surface to be bonded is cleaned by removal by techniques of chemical cleaning and / or electrochemical polishing.

A blade repair die 34 is then attached to blade stub 15 with its inner radial surface 44 located adjacent disk 12 of integral bladed rotor 10. The hydraulic cylinder 40 secures the two die halves 35, and hence the collar 24, to the blade stub 15. The bonding is typically performed in a high vacuum ( ^10-5 mmHg) under conditions of temperature and pressure sufficient to produce a metal stream. A vacuum environment is preferred to minimize or eliminate oxidation. The exact bonding conditions will vary depending on the material to be bonded. However, for a typical superalloy, the temperature is 1700 °
The pressure is between about F and 2100 ° F. (930 ° C. to 1150 ° C.), and the pressure with which the collar 24 and blade stub 15 are pressed together is on the order of 5 to 15 ksi. After the collar 24 and the blade stub 15 have been combined, the blade repair die 34 can be removed and the increased blade stub 46 (ie, the combined collar 2) can be removed.
4 and blade stub 15) can be machined to accept a replacement blade 42 (see FIG. 5).

According to the preferred embodiment, the replacement blade 4
2 includes a platform 48. The platform 48 of the replacement blade 42 provides an enlarged coupling surface that specifically resists deformation along the leading and trailing edges 50 and 52 of the replacement blade 42. The platform 48 of the replacement blade 42 also provides a surface on which the bonding force is applied. Then, once again, remove and clean debris and oxides from the surface to be bonded, and then apply a high vacuum (10 ⁻⁾ under conditions of sufficient temperature and pressure that the bonding typically results in metal flow. ⁵ mmHg).
The exact bonding conditions will vary depending on the material to be bonded. However, for a typical superalloy, the temperature may range from 1700 ° F to 2100 ° F (930 ° C to 1150 ° F).
C.) and the pressure is on the order of 5 to 15 ksi. Following this connection, the repair blade 54 (see FIG. 6) is machined until the desired blade formation is obtained. Following this machining, the portion of the repaired blade 54 that is being bonded is locally heat treated to ensure proper mechanical properties.

While the present invention has been illustrated and described in detail with reference to embodiments thereof, it will be understood by those skilled in the art that various changes can be made in the form and details without departing from the spirit and scope of the invention. There will be.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a part of a rotor with an integral blade in which the present invention is implemented.

FIG. 2 shows a repair device according to the invention mounted on the rotor part shown in FIG. 1;

FIG. 3 is an isometric view showing a state in which a blade stub integrated with a rotor is received in a collar.

FIG. 4 is an isometric view showing the blade stub and collar of the rotor shown in FIG. 3 being received in the die of the repair device according to the present invention.

FIG. 5 illustrates a collar coupled to a rotor blade stub and a replacement blade coupled to a platform formed by the coupled collar and stub.

6 is a view showing a state after excess material of a platform has been removed from the integral rotor blade shown in FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Rotor with integral blade 12 Disk 14 Blade 15 Blade stub 20 Leading edge 22 Trailing edge 24 Collar 26 Inner radial surface 28 Outer radial surface 30 Hollow part 32 Die side surface 34 Blade repair die 35 Die half body 36 Depression 37 Guide Pin 38 biasing means 40 hydraulic cylinder 42 replacement blade 44 inner radial surface 46 increased blade stub 48 platform 50 leading edge 52 trailing edge 54 repair blade

Continued on the front page (72) Inventor Randy Bee Helby, Southwest Glendale Street, Port St. Lucie, Florida, United States 34987 1926

Claims (7)

[Claims] 1. A method of replacing a rotor blade of a one-piece bladed rotor having a disk, comprising: (a) extending a blade stub portion extending outwardly from the disk and having a leading edge, a trailing edge, a suction side, and a pressure side. Removing the rotor blade so as to leave; (b) providing a collar having a hollow portion for receiving the blade stub portion; and (c) placing the blade stub portion within the hollow portion of the collar. (D) coupling the collar to the blade stub portion to form a platform with the blade stub portion and the collar; and (e) coupling a replacement rotor blade to the platform. A method of replacing a rotor blade. 2. The method of claim 1, wherein the hollow portion of the collar and the blade stub portion form a mating pair. 3. The method of replacing a rotor blade according to claim 1, further comprising: providing a die having a recess for receiving the collar; placing the collar in a recess of the die; Biasing the collar into contact with the blade stub portion using the die during the coupling to the stub portion. 4. The method of claim 3, wherein the hollow portion of the collar and the blade stub portion form a mating pair. 5. The method for replacing a rotor blade according to claim 4, wherein said die includes a first half and a second half. 6. A method for replacing a rotor blade according to claim 5, wherein one of said first and second halves includes a plurality of pins, and the other of said first and second halves. Comprises a plurality of holes for receiving said pins, wherein said pins received in said holes position said first and second halves relative to each other. 7. The method of claim 6, further comprising the step of removing excess platform material desired for the replacement rotor blade.