JP2002129901A - Chip shroud structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simplified chip shroud structure with its weight reduced. SOLUTION: On the chip shroud 2 which is formed on outside tip toward disc trace of plural tarbine rotor blades 1 that is attached toward disc track, a state which is attached each other to the chip body 2a on the tarbine rotor blade 1 that is next toward track forms triangle state that have smooth top seeing from toward disc rotate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip shroud structure.

[0002]

2. Description of the Related Art Turbine blades (hereinafter referred to as "disks") circumferentially disposed for use in a jet engine are formed at the radially outer ends of the turbine blades at the tips of adjacent turbine blades. The tip shroud is provided so as to contact the tip shroud to prevent resonance of the turbine blade during high-speed rotation and to prevent hot gas from leaking outside the turbine blade.

FIGS. 3 to 7 show a conventional example of a turbine blade provided with such a chip shroud.
Reference numeral 1 denotes a turbine rotor blade mounted on the outer periphery of a disk (not shown) at predetermined intervals in a circumferential direction, and 2 is fixed to a radial outer end of the turbine rotor blade 1 by means such as welding. Reference numeral 3 denotes a turbine casing in which a turbine blade 1 on which a chip shroud 2 is fixed is rotatably housed.

A chip shroud 2 is directly fixed to the tip of the turbine rotor blade 1 and has a plate-shaped chip main body 2a having a predetermined thickness formed so as to extend in the disk circumferential direction and the disk axial direction. 2a, two chip fins 2b projecting outward in the radial direction of the disk, extending in the disk rotation direction, and integrally fixed at predetermined intervals in the axial direction of the disk.

That is, as viewed from the radially outer side of the disk, that is, the radially outer side of the turbine casing 3, both sides of the chip main body 2a in a direction parallel to the disk axial direction L are as shown in FIGS. Turbine blade 1
Are formed in a straight line parallel to the rotation direction (rotating blade rotation direction) D of the blade, and an intermediate portion in a direction parallel to the disk axis direction L is the blade rotation direction D at the tip of the rotating blade rotation direction D.
The protruding portion is formed in a triangular shape so as to form an acute angle toward the blade surface, and is cut away in a triangular shape at the rear end portion in the blade rotating direction D so as to form an acute angle in the blade rotating direction D to form a recess 4. Have been.

When the turbine blades 1 are mounted on a disk, the adjacent turbine blades 1 and 1 have a tip body 2a fixed to the turbine blade 1 on the rear side in the blade rotation direction D. The triangular part of the moving blade rotation direction D
The tip body 2a fixed to the front turbine rotor blade 1 is fitted into the triangular recess 4 of the tip body 2a. The tip body 2a on the front side can be brought into contact with the rotation-side rear side surface 2d of the chip body 2a.

Further, as shown in FIG.
In a direction parallel to the disk axis direction L, the shape is inclined so as to rise from the gas inlet side A to the gas outlet side B with respect to the turbine rotor blade 1 and is formed so as to be sandwiched between the two tip fins 2b. The rotation-direction front side surface 2c and the rotation-direction rear side surface 2d are trapezoidal in a direction parallel to the disk axis direction L.

In the above-described jet engine, high-temperature gas generated by combustion of fuel in a combustion chamber (not shown) is introduced into the turbine blade 1 from the gas inlet side A, and the turbine is rotated at high speed by the expansion energy of the high-temperature gas. Let me do. At this time, the turbine rotor blades 1, 1 adjacent to each other in the rotor blade rotation direction D are in contact with each other via the rotation-direction rear side surface 2d and the rotation-direction front side surface 2c of the chip body 2a, so that the turbine rotates at a high speed. Even when the turbine blade 1 does not resonate, the high temperature gas does not leak from the turbine blade 1 to the outer peripheral side due to the presence of the chip shroud 2.

[0009]

SUMMARY OF THE INVENTION The above-mentioned turbine rotor blade 1
In the chip main body 2a of FIG.
4 is formed in a trapezoidal shape as shown in FIG. 4, and its area is large, so that the weight increases, so that the turbine blade 1
There is a possibility that the centrifugal force and the generated stress acting on the surface will increase, and the strength margin will decrease.

As shown in FIGS. 3 and 5, when the tip shroud 2 is viewed from the outside in the radial direction of the turbine casing 3, the tip body 2 a is located on the gas outlet side B with respect to the tip of the turbine bucket 1. If the distance from the front side 2c of the rotation direction to the front side of the turbine blade 1 is S1, and the distance from the side 2d of the rotation direction to the rear side of the turbine blade 1 is S2, S1> S2. It is fixed in the position where it was.

For this reason, the plane center of gravity G1 of the tip body 2a and the center of gravity G2 of the cross section of the turbine rotor blade 1 are located.
As a result, a high stress is generated at the connection between the turbine blade 1 and the tip main body 2a during rotation, and a sufficient margin in strength cannot be obtained.

Further, there is a chip fin 2b and a trapezoidal portion outside the chip main body 2a in the disk radial direction, and the radius of curvature R of an arc portion between one of the chip fins 2b and the trapezoidal portion is small. However, there are problems such as complicated processing, high processing cost, and difficulty in repair.

The present invention has been made in view of the above circumstances, and has as its object to provide a tip shroud structure having a reduced weight and a simplified structure.

[0014]

According to a first aspect of the present invention, there is provided a tip shroud structure provided at a radially outer end of a turbine rotor blade arranged in a circumferential direction of a disk and arranged from a radial direction of the disk. A chip shroud structure having a plate-like chip body when viewed from the center, in a disk axial direction intermediate portion of the chip body, which is adjacent to the disk circumferential direction and can contact each other, is smooth when viewed from the disk rotation direction. It is formed in a triangular shape having an apex.

According to a second aspect of the present invention, there is provided a chip shroud structure, comprising: a triangular portion at an intermediate portion in the disk axial direction, which is capable of abutting each other between adjacent chip bodies in the disk circumferential direction; An arc having a large radius of curvature is formed between the tip fin and the tip fin.

In the tip shroud structure according to a third aspect of the present invention, the position of the center of gravity of the tip shroud viewed from the outside in the disk radial direction is substantially matched with the position of the center of gravity in the cross section of the turbine blade.

According to the present invention, since the weight of the tip shroud can be reduced, the centrifugal force and generated stress acting on the turbine blade during rotation can be reduced, and the strength margin can be improved. Sometimes it is possible to reduce the stress generated at the connection between the turbine blade and the tip shroud, and it is possible to obtain a sufficient margin in strength,
Further, the structure is simplified, the processing cost is reduced, and the repair is easy.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 and 2 show an example of an embodiment of the present invention. In the drawings, portions denoted by the same reference numerals as those in FIGS. 3 and 4 represent the same components.

In the turbine moving blade 1 in the illustrated example, the rotating front side surface 2c and the rotating rear side surface 2d of the adjacent turbine moving blades 1 contacting each other are viewed from the rotating direction D of the turbine moving blade 1. As shown in FIG. 2, the shape of the lever is formed in a triangular shape with a gentle arc at the top, and also a valley on both sides with a gentle arc.

For this reason, the area of the front side surface 2c in the rotation direction and the rear side surface 2d in the rotation direction of the turbine blade 1 has a smaller area than that in the case of a trapezoidal shape, so that the weight of the tip shroud 2 is reduced. It is reduced. Therefore, the centrifugal force and the generated stress acting on the turbine blade 1 during rotation of the turbine are reduced, and the strength margin can be improved.

As shown in FIG. 1, when the tip shroud 2 is viewed from the outside of the turbine casing 3 in the radial direction,
The tip main body 2a has a turbine blade 1 on the gas outlet side B.
The distance from the front side 2c in the rotation direction to the front side of the turbine blade 1 is S1, and the distance from the rear side 2d in the rotation direction to the rear side of the turbine blade 1 is S2.
Then, it is fixed at a position where S1 = S2 is well balanced.

Therefore, the plane center of gravity G1 of the tip body 2a and the center of gravity G2 of the cross section of the turbine rotor blade 1 are located.
As a result, the stress generated at the connection between the turbine blade 1 and the tip body 2a during rotation can be reduced, and a sufficient margin in strength can be obtained.

Further, the radius of curvature R of the arc between the tip fin 2b protruding outward in the turbine radial direction of the tip body 2a and the triangular portion of the front side surface 2c in the rotational direction or the rear side surface 2d in the rotational direction is calculated. Since it can be made larger than the conventional one, the structure is simplified, the processing cost is reduced, and the repair is easy.

Note that the tip shroud structure of the present invention
It is needless to say that the present invention is not limited to the above illustrated examples, and various changes can be made without departing from the gist of the present invention.

[0025]

As described above, the first aspect of the present invention is as described above.
According to the tip shroud structure described in (1) to (3), I) the weight of the tip shroud can be reduced, so that the centrifugal force and the generated stress acting on the turbine rotor blade during rotation of the turbine are reduced, and the strength margin is improved. II) The stress generated at the connection between the turbine blade and the tip shroud during rotation can be reduced, and a sufficient margin in strength can be obtained. III) The structure is simplified and the processing cost is reduced. And various excellent effects such as easy repair can be achieved.

[Brief description of the drawings]

FIG. 1 is a view showing an example of an embodiment of a tip shroud structure of the present invention, showing a state in which a tip shroud is viewed from a radial outside of a turbine casing.

FIG. 2 is a view taken in the direction of arrows II-II in FIG.

FIG. 3 is a view showing an example of a conventional tip shroud structure in a state where the tip shroud is viewed from a radial outside of a turbine casing.

4 is a view in the direction of arrows IV-IV in FIG. 3;

FIG. 5 is a view showing a state where turbine blades are arranged in a turbine rotation direction in a conventional tip shroud structure and viewed from a radially outer side of a turbine casing.

6 is a view in the direction of arrows VI-VI in FIG. 5;

FIG. 7 is a cross-sectional view showing a state in which a tip body of a tip shroud of one turbine blade is engaged with a lower surface of a tip body of a tip shroud of an adjacent turbine blade when the turbine blade is rotating.

[Description of Signs] 1 Turbine blade 2 Chip shroud 2a Chip body 2b Tip fin 2c Front side surface in rotation direction 2d Rear side surface in rotation direction D Rotation direction (rotor blade rotation direction) (disk circumferential direction) G1 Center of gravity position G2 Center of gravity position L Disc axis direction R Curvature radius

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Shozo Yabuta, Inventor Shozo Yabuta 3-5-1 Mukodaicho, Tanashi-shi, Tokyo Ishikawa Shima-Harima Heavy Industries Co., Ltd. Tanashi Plant (72) Inventor Hidetoshi Yado 3-chome, Mukodaicho, Tanashi-shi, Tokyo No.5-1 Ishikawa Shima-Harima Heavy Industries Co., Ltd. Tanashi Plant F-term (reference) 3G002 BA02 BB03

Claims (3)

[Claims] 1. A chip shroud structure provided at a radially outer end of a turbine rotor blade arranged in a disk circumferential direction and having a plate-shaped chip body viewed from the disk radial direction. A tip shroud, wherein the shape of the tip body in the axial direction of the disc, which is adjacent to and can contact with each other in the disc circumferential direction, is formed in a triangular shape having a smooth top when viewed from the disc circumferential direction. Construction. 2. A method according to claim 1, wherein a triangular portion at an intermediate portion in a disk axial direction of the chip main body adjacent to each other in a circumferential direction of the disk and a chip fin formed on both sides of the chip main body in the disk axial direction. The tip shroud structure according to claim 1, wherein an arc having a large radius of curvature is formed. 3. The tip shroud structure according to claim 1, wherein the position of the center of gravity of the tip shroud viewed from the outside in the disk radial direction is substantially matched with the position of the center of gravity in the cross section of the turbine blade.