JP2003314369A - Dovetail shim - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a damage when assembling a fan blade attached with a dovetail shim to a fan disk in manufacturing a fan rotor vane. <P>SOLUTION: The end 12 of this dovetail shim 10 is so formed not to damage an abutment surface 28 of the fan disk, when the fan blade 4 is assembled to the fan disk 2. Practically, the end of this dovetail shim attached to the dovetail part 18 of the fan blade is once expanded outward in a waist part 22 of the dovetail and then introverted, and the introverted edge part 24 of the end tip is formed into a wave shape with a clearance formed toward the dovetail. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dovetail shim, and more particularly, to protecting a contact surface between a dovetail portion of a fan blade and a disk post of a fan disk in manufacturing a fan rotor blade of a turbofan engine. The present invention relates to the shape of a dovetail shim held between a fan disk and a fan blade.

[0002]

2. Description of the Related Art A fan blade arranged at the forefront of an engine for taking in air into the engine is composed of a fan disk driven by power from a turbine, a fan blade fixed to the fan disk, and the like. .

FIG. 4 is an enlarged view of a portion where the fan blade and the fan disk are assembled. Fan disk (2)
Has a concave disc post (1
4) are formed at equal intervals, and fan blades can be radially attached to each disk post. The disc post is formed with a constricted portion (16) constricted at the opening (15), and the bottom portion located on the axial side is formed into a flat surface.

On the other hand, the fan blade (4) is formed with a dovetail portion (18) which is inserted into and fixed to the disc post at the end thereof. A waist portion (22) for temporarily increasing the length in the fan rotation direction is formed in the dovetail portion, and the waist portion is the waist portion (16) of the disk post.
By contacting with the fan blade, the fan blade does not come out of the fan disk in the radial direction even when the fan rotates. Further, the tip of the dovetail portion is formed into a flat surface.

With the fan blade (4) assembled to the fan disk (2), a spacer (26) is inserted from the axial direction of the engine into the space formed between the bottom of the disk post and the tip of the dovetail section, and the fan is inserted. The blade is biased radially outward. As a result, the fan blade is fixed to the fan disk without rattling.

A dovetail shim (30) is held between the dovetail portion (18) of the fan blade (4) and the disk post (14) of the fan disk (2). The dovetail shim (30) is gripped between the surfaces (contact surface (28)) where the dovetail portion and the fan disk contact with each other, and is attached so as to cover the dovetail portion.

Since the blade height of compressor and turbine moving blades is small, the blades are usually assembled directly to the disk, but the fan blades for taking in the outside air into the engine have a large blade height, and the fan blades are in operation. A large force or moment acts on the contact surface that supports
This portion is likely to be worn. Therefore, particularly in mass-produced turbofan engines, the contact surface is mainly worn by gripping a thin plate-like dovetail shim made of a metal material having a hardness lower than that of the fan disk or fan blade on the contact surface. It is generated in the dovetail shim to prevent wear of the fan disk and the dovetail itself. As a result, when the fan blade is overhauled, it is often necessary to replace only the dovetail shim without replacing the fan disk or fan blade, and maintenance costs can be reduced.

Here, the dovetail shim is made of a thin plate material of elastic metal and is formed in a C-shape that substantially matches the shape of the dovetail portion, and covers the dovetail portion and clips it. Also, the dovetail shim has its end located on the base side of the tabtail. Further, the edge portion (24) at the tip of the end portion of the dovetail shim has a contact surface (2
8) Spreads outward to cover 8).

This is for convenience of assembling the fan blade (4) to the fan disk (2), and as will be described in the process of assembling the fan rotor blade described below, the dovetail shim (30) is attached to the dovetail portion. This is for locking the fan blade thus formed to the constricted portion (16) of the disk post (14).

Next, a process for assembling the above-mentioned fan rotor blade will be described. First, an end portion of a C-shaped dovetail shim made of a thin plate-shaped elastic metal in accordance with the shape of the dovetail portion is slightly pushed apart and inserted into the dovetail in the axial direction of the engine to be fixed. At this time, by forming the dovetail shim so as to generate an inward biasing force, the dovetail shim chucks the dovetail portion and is not easily detached from the dovetail. Insert the dovetail with the dovetail shim into the disc post formed on the fan disc from the axial direction. At this time, the entire dovetail shim is housed in the disc post. The fan blade inserted in the disc post is pulled outward in the radial direction to bring the constricted portion of the disc post and the waist portion of the dovetail portion into contact with each other while gripping the dovetail shim. At this time, the edge of the tip of the dovetail shim end, which is formed to spread outward, is compressed and bent inward along the shape of the constricted part, and after bending over the most constricted part, the constricted part is removed from the outside. It urges toward and chucks the binding part. The spacer is axially inserted into the space formed between the end of the dovetail and the bottom of the disc post. As a result, the fan blade is urged outward in the radial direction and fixed to the fan disk without rattling.

[0011]

Although the above-mentioned dovetail shim is useful for avoiding the wear of the fan disk and the dovetail itself, the dovetail shim having the conventional shape as shown in FIG. 5 pulls the fan blade. When the fan blade is lifted to assemble the fan blade (previous paragraph process), the edge portion (24) at the end of the end of the dovetail shim formed to spread outward scratches and scratches the abutment surface (28) of the disc post. There was a possibility that it would end up. Therefore, in assembling, it is necessary to pay close attention so as not to cause a decrease in strength of the manufactured fan rotor blades, and it takes much time and effort to assemble. In particular, since a large force or moment acts on this contact surface, it has been necessary to pay close attention to prevent the occurrence of such scratches in order to ensure the safety and reliability of the fan rotor blade.

The present invention has been made in view of the above problems, and when a fan blade having a dovetail shim attached to a dovetail portion is attached to a disk post of a fan disk in the production of a fan rotor blade of a turbofan engine, An object of the present invention is to provide a dovetail shim having a shape that can be easily assembled without damaging the contact surface.

[0013]

A dovetail shim according to the present invention for achieving the above object is provided between a fan disk (2) and a fan blade (4) constituting a fan rotor blade (1) of a turbofan engine. A dovetail shim to be gripped by an end portion (12) of the dovetail shim (10)
Is formed so as not to damage the fan disk when the fan blade is assembled to the fan disk.

In the conventional dovetail shim, it is necessary to pay close attention to prevent damage to the abutment surface when assembling the fan blade, and it took time to assemble the fan blade. The focus is on the shape of the end of the dovetail shim in order to provide a high fan blade with an easy assembly method.

More specifically, the fan disk (2) has a concave disk post (14) on the outer periphery thereof.
Are formed at equal intervals, the disc post is formed with a constricted portion (16) that constricts at an opening (15) thereof, and the fan blade (4) is formed with a dovetail portion (18) at an end thereof. The dovetail is formed with a waist portion (22) for temporarily increasing the length in the circumferential direction of the fan, and the dovetail shim (10) is grasped between at least the surfaces where the constricted portion and the waist portion are in contact with each other. And a thin plate material that is detachably attached to the dovetail portion.

Further, the end portion (12) of the dovetail shim (10) mounted on the dovetail portion (18) once spreads outward and then inwards, and the edge portion of the inward end tip. (24) has a corrugated shape with a gap between it and the dovetail.

According to the dovetail shim of the present invention, since the end portion of the tabtail shim is inwardly rounded, the fan blade is pulled up, and the dovetail shim is once pushed inward to be bent to assemble the fan blade to the disk post. Even in this case, the edge portion does not scratch and damage the contact surface.

Further, by forming the dovetail shim in a wave shape so that the edge portion of the tip of the inwardly directed end portion has a gap between it and the dovetail portion, even if the dovetail bends when the dovetail gets over the constricted portion of the disk post, The edge does not damage the dovetail.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The dovetail shim of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a perspective view of a dovetail shim 10 of the present embodiment, and FIG. 2 is a front view showing a mounting portion where a fan blade is mounted on a fan disk. Since the dovetail portion and the disk post are the same as those described in [Prior Art], the same reference numerals are given and duplicate description of their shapes and the like will be omitted.

As shown in FIG. 1, the dovetail shim 10 has a C-shape for covering the dovetail portion and is made of a thin plate-shaped metal material having a hardness lower than that of the fan disk or the fan blade. Further, the dovetail shim 10 is highly elastic, and the tabtail portion is clipped from both sides in a state of being attached to the dovetail portion.

The end portion 12 of the dovetail shim 10 has a corrugated shape in which the end portion 12 once spreads outward and then inwards. Figure 2
When the dovetail 18 is assembled to the disc post 14 as shown in FIG. 5, the outwardly expanded portion is adapted to cover the curved surface of the constricted portion 16 of the disc post, and the inwardly directed edge A constant gap is formed between the portion 24 and the dovetail portion 18. By gripping the dovetail shim 10 between the dovetail portion 18 and the abutment surface 28 of the disc post 14, the contact surface is mainly worn on the dovetail shim, and the dovetail portion and the disc post themselves are worn. Can be prevented. The function of this dovetail shim is similar to that of the conventional dovetail shim.

Next, the operation of the dovetail shim of this embodiment in the process of assembling the fan blade will be described with reference to the drawings.

First, the dovetail portion 18 of the fan blade 4 to which the dovetail shim 10 of this embodiment is attached is axially inserted into the disc post 14 formed on the fan disc 2. In this state, the entire dovetail portion is included in the disc post (FIG. 3A).

Next, the fan blade 4 inserted in the disk post 14 is strongly pulled outward in the radial direction. At this time, the end portion 12 of the dovetail shim 10 is once inwardly compressed and bent along the shape of the constricted portion 16 of the disk post.
Also at that time, the edge portion 24 is formed on the inwardly curved surface,
Since the back surface of the fan disk contacts the fan disk, the edge portion 24 does not scratch and damage the contact surface 28 of the fan disk. When the fan blade is further pulled up, the end 12 of the dovetail shim rides over the most constricted part of the disk pocket and spreads outward, urging and catching the constricted part 16 outwardly, so that the fan blade 4 is caught in the fan disk. Lock to 2. At this time, the constricted portion of the disc post and the waist portion of the dovetail portion come into contact with each other while the dovetail shim is held therebetween. It should be noted that the inwardly directed edge portion 24 is formed such that the inwardly directed edge portion has a predetermined clearance between the dovetail shim 18 and the dovetail portion 18 even when the end portion 12 of the dovetail shim bends over the most constricted portion of the disk pocket. Since it does not contact the dovetail portion, it does not damage it (Fig. 3 (b)).

Finally, a spacer is inserted from the axial direction of the engine into the space formed between the bottom of the disk post and the tip of the dovetail to urge the fan blades radially outward,
Fix the fan blade to the fan disk (Fig. 3
(C)).

As described above, by using the dovetail shim of the present invention to prevent the contact surface from being damaged during the manufacture of the fan rotor blade, the assembly, which has required a great deal of attention in the past, can be facilitated and the safety can be improved. It is possible to provide a high fan moving blade.

The present invention is not limited to the above-mentioned embodiments, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

[0028]

As described above, according to the dovetail shim of the present invention, the wear of the fan disk and the dovetail portion itself is prevented as in the conventional case, and the tip of the dovetail shim is assembled even when the fan blade is assembled to the fan disk. The edge part of does not damage the contact surface of the disk post,
A dovetail shim that can be used to manufacture highly safe and reliable fan blades is provided.

[Brief description of drawings]

FIG. 1 is a perspective view of a dovetail shim of this embodiment.

FIG. 2 is a front view showing a mounting portion in a state where a fan blade is mounted on a fan disk.

FIG. 3 is a front view showing a manufacturing step of the dovetail shim of this embodiment.

FIG. 4 is a front view showing an assembly position of a conventional fan blade and a fan disk.

FIG. 5 is a front view showing a step of manufacturing a conventional dovetail shim.

[Explanation of symbols]

1 Fan blade 2 fan disk 4 fan blades 10 Dovetail Sims 12 end 14 disk posts 15 openings 16 Generalization Department 18 Dovetail section 22 waist 24 Edge 26 Spacer 28 Contact surface 30 Dovetail Sims

Claims (3)

[Claims] 1. A dovetail shim gripped between a fan disk (2) and a fan blade (4) constituting a fan rotor blade (1) of a turbofan engine, the end of the dovetail shim (10). The dovetail shim, wherein the portion (12) is formed so as not to damage the fan disk when the fan blade is assembled to the fan disk. 2. The fan disk (2) is provided with concave disk posts (14) at equal intervals on the outer periphery thereof, and the disk posts have constricted portions (16) constricted at their openings (15). The fan blade (4) is formed with a dovetail portion (18) at its end, and the dovetail is formed with a waist portion (22) for temporarily increasing the length in the fan circumferential direction, The dovetail shim (10) is made of a thin plate material that is gripped between at least the surface where the constricted portion and the waist contact, and is detachably attached to the dovetail portion. Dovetail sim as described in. 3. The end portion (12) of the dovetail shim (10) attached to the dovetail portion (18) is inwardly expanded and then inwardly directed, and an inwardly directed edge portion of the tip end portion. The dovetail shim according to claim 2, wherein (24) has a corrugated shape with a gap provided between the dovetail and the dovetail.