JPH11324605A - Structure for mounting moving blade - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce bending moment in the structure for mounting a moving blade by reducing asymmetry of the shape of blade grooves as much as possible. SOLUTION: This structure is provided with a disc 12 rotatable around the center axis, and a plurality of moving blades 13 mounted by inserting 2 blade root 13a thereof into a plurality of blade grooves 14 formed on the peripheral surface of the disc 12 intervals in the peripheral direction. The moving blade 13 is mounted to the blade groove 14 whose center axis Y is slanted in the rotational direction with respect to the direction of the disc radius X.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for mounting a moving blade of a turbine, a fan, or a compressor used for a rotary machine such as a gas turbine engine.

[0002]

2. Description of the Related Art As shown in FIG. 3, a rotor 1 used in a gas turbine engine or the like is constructed by arranging a plurality of moving blades 3 at intervals on an outer peripheral surface of a disk-shaped disk 2. ing. In general, the rotor blades 3 are required to provide different damping to the vibrations by mechanical friction and to be made of different materials due to a difference in characteristics required between the rotor blades 3 and the disk 2. Thus, the disk 2 is often formed in a divided state.

[0005] On the outer peripheral surface of the disk 2, implantation grooves 4 for mounting the moving blades 3 are formed in the thickness direction of the disk 2 at intervals in the circumferential direction. The implantation groove 4 is used to support the rotating blade 3 against a large centrifugal force acting radially outward on the rotating blade 3 rotated at a high speed.
And a wave shape (fir tree shape) as shown in FIG.
Or it is formed in a dovetail shape.

[0004] The moving blade 3 includes a blade portion 3a disposed in a flow passage (not shown) for flowing gas, and a platform 3b corresponding to the root of the blade portion 3a. Is formed with a wing root portion 3c which is a fir-tree-shaped fixing portion to be fitted into the implantation groove 4.

The disk 2 and the rotor blade 3
In order to form the rotor 1 with the blade 2, the blade 3 is moved in parallel in the thickness direction of the disk 2 with the blade root 3c of the blade 3 aligned with the implant groove 4 at the end face of the disk 2. As a result, the blade root 3c is inserted into the implantation groove 4, and the blade 3 is restrained in the radial direction of the disk 2.

A blade root 3c of the rotor blade 3 of the rotor 1
Is a part that is important for strength, so it is necessary to reduce the stress as much as possible. The blade root 3c is subjected to a tensile force and a bending moment due to an external force such as a centrifugal force or the force of a high-temperature and high-pressure gas during rotation, and it is difficult to reduce the tensile force. Can be reduced by devising.

Conventionally, in order to reduce the bending moment, as shown in FIGS. 4 and 5, the center axis of the implant groove 4 into which the blade root 3c is inserted is set in the circumferential direction (arrows in FIGS. 4 and 5). Direction), a bending moment due to centrifugal force is artificially generated in the attached rotor blade 3, and the bending moment is reduced by balancing the bending moment with a bending moment due to an external force.

[0008]

However, in the conventional rotor blade mounting structure, when the implant groove 4 has an angle with respect to the axial direction of the disk 2, the implant groove 4 on the disk 2 side at the front and rear end faces. There is a possibility that this may promote the left-right asymmetry of the shape and may cause a problem in strength. In addition, when the radial position of the implantation groove 4 is high, the effect of the offset is reduced, so that the offset amount is necessarily set to be large.
Also in this case, the shape of the implantation groove 4 becomes left-right asymmetric, which may cause a problem in strength.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problem, and has as its object to provide a rotor blade mounting structure capable of reducing bending moment by minimizing left-right asymmetry in the shape of an implantation groove. Aim.

[0010]

The present invention has the following features to attain the object mentioned above. That is, in the rotor blade mounting structure according to the present invention, a disk-shaped disk that is rotated about a central axis, and a plurality of implant grooves formed on the outer peripheral surface of the disk at circumferential intervals with respect to the blade root portion. A plurality of moving blades inserted and attached, wherein the moving blade,
A technique is employed in which the center axis is inclined in the rotation direction with respect to the radial direction of the disc and the disc is attached to the implantation groove.

In this moving blade mounting structure, since the moving blade is mounted in the implantation groove formed by inclining the central axis in the rotational direction with respect to the radial direction of the disk, the bending moment due to external force and the bending moment are reduced. A bending moment due to centrifugal force for balancing is effectively generated in the moving blade in the inclined state, and the degree of left-right asymmetry of the implantation groove is reduced as compared with the case where the implantation groove is offset in the circumferential direction. In particular, even when the implantation groove is not inclined in the axial direction of the disc, the degree of left-right asymmetry is constant in the axial direction, and the shape in the axial direction is smaller than when the implantation groove is offset in the circumferential direction. Does not change, and the shape is simple.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a moving blade mounting structure according to the present invention will be described below with reference to FIGS. In these figures, reference numeral 11 denotes a rotor, 12 denotes a disk, 13 denotes a moving blade, and 14 denotes an implantation groove.

As shown in FIG. 1, the rotor 11 of the present embodiment includes a disk-shaped disk 12 and a plurality of moving blades 13 arranged on the outer peripheral surface of the disk 12 at intervals in the circumferential direction. doing. The disc 12 has a plurality of implantation grooves 14 penetrating in the thickness direction on the outer peripheral surface thereof at intervals in the circumferential direction, and the implantation grooves 14 are formed in a firtree shape or a dovetail shape. In this respect, it is common to the conventional example.

However, the disk 12 of the present embodiment
Is different from the conventional example in that the center axis Y is inclined in the rotation direction (the direction of the arrow in FIG. 1) with respect to the radial direction X of the disk 12. That is, the angle θ between the radial direction X of the disk 12 and the central axis Y of the implantation groove 14 is set in consideration of the bending moment due to the centrifugal force for balancing the bending moment due to the external force. Further, as shown in FIG. 2, the implantation groove 14 is formed to be inclined at a predetermined angle with respect to the axial direction of the disk 12.

The moving blade 13 has a platform 13b having a blade root portion 13a shaped to be inserted into the implantation groove 14. The platform 13b has a blade root portion 13a of the rotor blade 13 inserted into the implantation groove 14 of the disk 12,
When the rotor blade 13 is implanted on the outer peripheral surface of the disk 12, the blade 13 is formed in an annular shape to cover the outer peripheral surface of the disk 12 together with the platform 13 b of the adjacent rotor blade 13.

In this moving blade mounting structure, since the moving blade 13 is mounted in the implantation groove 14 formed by inclining the central axis in the rotational direction with respect to the radial direction X of the disk 12, external force is applied. The bending moment due to the centrifugal force for balancing with the bending moment due to the rotation is effectively generated in the moving blade 13 in the inclined state, and as shown in FIG. The degree of left-right asymmetry of the groove 14 can be reduced.

In particular, if the implantation groove 14 is not inclined in the axial direction of the disk 12, the degree of left-right asymmetry is constant in the axial direction, and the degree of axial asymmetry is smaller than when the implantation groove is offset in the circumferential direction. There is an advantage that the shape does not change in the direction and the shape is simple.

The present invention includes the following embodiments. (1) The above embodiment is applicable not only to a gas turbine but also to any rotor blade of a fan or a compressor. (2) Although the fir tree shape or the dovetail shape is adopted as the implant groove 14 of the disk 12 and the blade root of the rotor blade 13 inserted into the implant groove 14, any other shape may be used.

[0019]

As described above in detail, according to the moving blade mounting structure of the present invention, the moving blade is formed by tilting the center axis in the rotation direction with respect to the radial direction of the disk. Since it is attached to the groove, it has the following effects. Bending moment due to centrifugal force is effectively generated on the moving blade in the inclined state, and the degree of left-right asymmetry of the implanted groove can be reduced compared to the case where the implanted groove is offset in the circumferential direction. Risk can be reduced. If the implantation groove is not inclined in the axial direction of the disc, the degree of left-right asymmetry is constant in the axial direction, so that the shape of the implantation groove does not need to be three-dimensionally examined, which facilitates design and design. Can be improved.

[Brief description of the drawings]

FIG. 1 is a front view of a main part showing an embodiment of a moving blade mounting structure according to the present invention.

FIG. 2 is a plan view of a main part showing a disk in an embodiment of a moving blade mounting structure according to the present invention.

FIG. 3 is a perspective view showing a conventional example of a moving blade mounting structure according to the present invention.

FIG. 4 is a front view of a main part showing a conventional example of a rotor blade mounting structure according to the present invention.

FIG. 5 is a plan view of a main part showing a disk in a conventional example of a moving blade mounting structure according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Rotor 12 Disk 13 Blade 13a Blade root part 14 Implanted groove X Radial direction of disk Y Center axis of implanted groove

Claims (1)

[Claims] 1. A disk-shaped disk which is rotated around a central axis, and a plurality of blades which are inserted into and mounted on a plurality of implant grooves formed on an outer peripheral surface of the disk at intervals in a circumferential direction. A moving blade, wherein the moving blade is attached to the implantation groove formed by inclining a central axis in a rotational direction with respect to a radial direction of the disk. Mounting structure.