JP2003120201A - Turbine disk connecting mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide turbine disk connecting mechanism which can use materials different substantially in coefficients of thermal expansion for a turbine disk, can absorb the difference in thermal expansion caused by the difference in the coefficients of the materials, can transmit torque for driving a compressor, hardly causes center offset and has high flexural rigidity. SOLUTION: The connection section 13 of the turbine disk and a compressor shaft comprises a plurality of trapezoidal recessed grooves 13a provided in one of the two and a plurality of trapezoidal protruded sections 13b provided in the other one to be fitted to these recessed grooves 13a. The trapezoidal recessed grooves and the trapezoidal protruded sections from the inclined faces of a trapezoid respectively and contact each other at two faces 13c and 13d extending radially. A tie bolt is cylindrical in its hollow section and has a male thread section provided at one end of the tie bolt and threadedly engaged with the female thread section of the compressor shaft, and a head section provided at the other end of the tie bolt and is projected from the shoulder section of the turbine disk in a radial and outer direction, and is held tensioned. This holds the turbine disk pressed against to the side of the compressor shaft.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turbine disk coupling structure, and more particularly to a turbine disk coupling structure in which materials having greatly different thermal expansion coefficients (for example, ceramic composite materials) can be used for the turbine disk. .

[0002]

2. Description of the Related Art A conventional jet engine is composed of a compressor 1, a combustor 2, a turbine 3, etc., as shown in FIG. 4, and the turbine 3 has a large number of turbine blades 4 on its outer peripheral portion. It is composed of a disk 5 and a rotor 6 connecting the disk 5 to the compressor 1, and both ends thereof are supported by bearings 7. Further, the metal turbine disk 5 and the rotor 6 have flange portions 5a and 6a at their joints, respectively.
And are connected by bolts 8. With this structure, the air compressed by the rotation of the compressor 1 flows into the combustor 2, the combustor 2 generates high-temperature combustion gas, and the combustion gas drives the turbine 3, and the driving force of the rotor 6 drives the rotor 6. The compressor 1 is driven via this.

[0003]

In recent years, in order to improve the thermal efficiency of jet engines, it has been desired to raise the turbine inlet temperature. However, when the turbine inlet temperature reaches a high temperature of, for example, 1400 ° C. or higher, not only the turbine blades 4 but also the turbine disk 5 become a high temperature of 700 ° C. or higher, and there is a problem that conventional metals cannot be used due to insufficient high temperature strength. It was Therefore, the turbine disk 5 is made of ceramic or ceramic composite material (Fiber Reinforced) with high heat resistance.
Ceramic: FRC) has a large difference in thermal expansion with the rotor 6 made of metal (coefficient of thermal expansion is about 15 x 10 for metal).
^-6 / ° C., about 3 × 10 ^-6 / ° C. for ceramic). In the structure of FIG. 4, a large shearing force acts on the bolt 8 in the radial direction, which causes a problem of breaking the bolt. Furthermore, if they are allowed to thermally expand freely with each other, it is difficult to transmit a large torque for driving the compressor 1, and it is difficult to perform centering, and thus misalignment is likely to occur. However, there is a problem in that when both ends are supported, the joint is easily bent. In particular, the rotor 6 of the jet engine rotates at a high speed of, for example, 100,000 rpm or more, so that even if a misalignment or a decrease in rigidity of the joint portion occurs, a large vibration occurs.

The present invention was created to solve the above problems. That is, the object of the present invention is to
A material having a large difference in thermal expansion coefficient (for example, ceramic composite material) can be used for the turbine disk, a difference in thermal expansion due to a difference in thermal expansion coefficient can be absorbed, and torque for driving the compressor can be transmitted. It is an object of the present invention to provide a coupling structure for a turbine disk that is less likely to cause misalignment and has high bending rigidity.

[0005]

According to the present invention, a turbine disk having a plurality of turbine blades on its outer peripheral portion, a compressor shaft connected to one end of the turbine disk and extending in the axial direction, and a turbine screwed to the compressor shaft are provided. A tie bolt that fastens the disc to the compressor shaft, and a coupling portion between the turbine disc and the compressor shaft has a plurality of trapezoidal recessed grooves provided on one side thereof and a plurality of trapezoidal recessed grooves provided on the other side and fitted into the recessed grooves. The trapezoidal groove and the trapezoidal convex portion are in contact with each other on two surfaces that form a trapezoidal inclined surface and extend in the radial direction, and the turbine disk has a through hole that is concentric with the shaft center and the through hole. A shoulder portion protruding inward of the through hole is provided, and the compressor shaft has an internal thread portion concentric with the shaft center at an end on the turbine disk side, The tie bolt has a hollow cylindrical shape, and has a male screw portion provided at one end thereof and screwed into the female screw portion of the compressor shaft, and a head portion provided at the other end thereof and protruding radially outward from the shoulder portion of the turbine disk. And a tie bolt is held in a tensioned state by screwing the female screw portion and the male screw portion, whereby the turbine disc is pressed against the compressor shaft side to be held, and a coupling structure for a turbine disc is provided. .

The tie bolt is preferably made of a niobium alloy, a nickel alloy or a molybdenum alloy.

Further, the turbine disk is composed of a disk body having the outer peripheral portion and the coupling portion and a shaft portion having the shoulder portion, and the disk body and the shaft portion are respectively provided with an axial center at a boundary portion thereof. Has a vertical plane,
The planes are in close contact with each other. The compressor shaft includes a coupling portion coupled to one end of the turbine disk and a driving portion axially extending to the compressor. The coupling portion and the driving portion are coupled to each other by an axially extending spline. Is preferred.

According to the above-mentioned structure of the present invention, the connecting portion between the turbine disk and the compressor shaft has a plurality of trapezoidal concave grooves provided on one side thereof and a plurality of trapezoidal convex grooves provided on the other side thereof and fitted into the concave grooves. The trapezoidal concave groove and the trapezoidal convex portion are in contact with each other on two radially extending surfaces that form a trapezoidal inclined surface, so that the compressor shaft and the turbine disk are radially aligned along the two surfaces. They can freely thermally expand each other. In addition, since the turbine disk is pressed against the compressor shaft and held by the extension of the tie bolts screwed onto the compressor shaft, the compressor shaft and the turbine disk are kept in contact with each other while the two surfaces forming the trapezoidal inclined surface are in contact with each other. It can be thermally expanded in the axial direction.

Therefore, it is possible to use materials (for example, ceramic composite materials) having greatly different thermal expansion coefficients for the turbine disk, and it is possible to absorb the difference in thermal expansion due to the difference in thermal expansion coefficient. Further, since the connecting portion between the turbine disk and the compressor shaft is composed of the trapezoidal concave groove and the trapezoidal convex portion fitted into the trapezoidal concave groove, a large torque for driving the compressor can be transmitted. Further, since the two surfaces forming the trapezoidal inclined surface extend in the radial direction, the center is automatically aligned by the movement along the surface, and the misalignment is unlikely to occur. Furthermore, since the connecting portion between the turbine disk and the compressor shaft consists of a trapezoidal concave groove and a trapezoidal convex portion that fits into this groove, and is tightened with tie bolts, the connecting portion can receive a bending moment and flexural rigidity. Can be increased.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described below with reference to the drawings. In each figure,
Common parts are assigned the same reference numerals and used. Figure 1
2 is a coupling structure diagram of a turbine disk according to the present invention, and FIG. 2 is an enlarged view of a main part of FIG. 1. 1 and 2, the coupling structure of the present invention includes a turbine disk 12 having a plurality of turbine blades 4 on an outer peripheral portion 11a, and a compressor shaft 14 which is coupled to one end of the turbine disk 12 by a coupling portion 13 and extends in the axial direction. , Tie bolts 16 that are screwed onto the compressor shaft 14 and fasten the turbine disk 12 to the compressor shaft 14.

The turbine disk 12 is made of a material having high heat resistance, for example, ceramic or ceramic composite material.
The coefficient of thermal expansion of the ceramic composite material is, for example, about 3 × 10 ^−6.
/ ° C.

In FIG. 2, the turbine disk 12 is
It has a through hole 11b concentric with the axis Z and a shoulder 11c protruding inward of the through hole 11b. Further, the compressor shaft 14 has a female screw portion 15 concentric with the axis Z at the end portion on the turbine disk side. Furthermore, the tie bolt 16 is
A male screw portion 16 having a hollow cylindrical shape, which is provided at one end thereof and is screwed with the female screw portion 15 of the compressor shaft 14.
a and a shoulder portion 11 of the turbine disk 12 provided at the other end
and a head portion 16b that projects radially outward from c.
Further, in this drawing, a spline 16c for rotating the tie bolt 16 about the axis Z is provided inside the other end of the tie bolt 16. With this spline 16c, the tie bolt 16 is rotated about the axis Z, and the male screw portion 16a of the tie bolt 16 is moved to the compressor shaft 1
The tie bolt 16 can be held in a tensioned state by being screwed into the female screw portion 15 of No. 4 so that the turbine disk 12 can be pressed and held against the compressor shaft side.

The tie bolt 16 is made of niobium (Nb) alloy,
It is preferably made of a nickel (Ni) alloy or a molybdenum (Mo) alloy. That is, about 7 × 10 ⁻⁶ / ° C. for niobium (Nb) alloy and about 5 for molybdenum (Mo) alloy.
× has a thermal expansion coefficient of about 10 ^-6 / ° C., compared to the ceramic or ceramic composite material ordinary metal (thermal expansion coefficient α of about 14 to 15 × 10 ^-6 / ° C.) (about 3 × 10 ^-6 / Degree C)
Therefore, the change in tensile stress (and elongation) of the tie bolt 16 due to thermal expansion can be minimized.

Further in FIG. 2, the turbine disk is
A disk body 12a having the outer peripheral portion 11a and the coupling portion 13, and a shaft portion 12 having the shoulder portion 11c.
b. Disk body 12a and shaft portion 12b
Each has a plane perpendicular to the axis Z at its boundary,
The two planes are in close contact with each other. With this configuration, the shaft portion 12b can be held integrally with the disc body 12a.

In FIG. 2, the compressor shaft 14 includes a coupling portion 14a coupled to one end of the turbine disk 12 and a driving portion 14b extending axially to the compressor.
The connecting portion 14a and the driving portion 14b are connected to each other by a spline 14c extending in the axial direction. With this configuration, the torque transmitted to the coupling portion 14a can be transmitted to the driving portion 14b via the spline 14c.

FIG. 3 is a detailed view of the coupling structure according to the present invention, (A) is a sectional view taken along the line AA of FIG. 2, (B).
Is a state at the time of thermal expansion thereof, and (C) is a plan view of (A) seen from above. As shown in FIG. 3, the coupling portion 13 between the turbine disk and the compressor shaft has a plurality of trapezoidal recessed grooves 13 a provided on one side and a recessed groove 1 provided on the other side.
It is composed of a plurality of trapezoidal protrusions 13b fitted in 3a. The trapezoidal groove 13a and the trapezoidal protrusion 13b are four in this figure, but may be two or three, or five or more.

The trapezoidal concave groove 13a and the trapezoidal convex portion 13b respectively have two surfaces 13c and 13d forming a trapezoidal inclined surface, and these two surfaces 13c and 13d extend in the radial direction and are in contact with each other. . In addition, the two surfaces 13 extending in the radial direction
As illustrated in FIG. 3 (B), the angle θ in the circumferential direction formed by c and 13d indicates that the movement of the two surfaces 13c and 13d of the compressor shaft 14 due to the relative thermal expansion corresponds to the two surfaces 13c of the turbine disk 12. , 13d. Furthermore, it is preferable that the trapezoidal inclination angle of the coupling portion 13 shown in FIG. 3 (C) is 15 to 45 °. In addition,
The two surfaces 13c and 13d are spiral surfaces, and it is desirable that the inward extension of these spiral surfaces pass through the axis Z. With such a configuration, the movement of the two surfaces 13c and 13d of the compressor shaft 14 due to the relative thermal expansion can be determined so as to accurately follow the two surfaces 13c and 13d of the turbine disk 12. Alternatively, the two surfaces 13c and 13d may be flat surfaces, and this condition may be partially satisfied.

With the above structure, the two surfaces 13c, 13d
Along the axis, the compressor shaft 14 and the turbine disk 12 are free to thermally expand each other in the radial direction. Further, since the turbine disk 12 is pressed against the compressor shaft side and held by the extension of the tie bolts 16 screwed onto the compressor shaft 14,
The compressor shaft 14 and the turbine disk 12 can be thermally expanded in the axial direction while the two surfaces 13c and 13d forming the trapezoidal inclined surface are in contact with each other.

Therefore, the turbine disk 12 can be made of a material having a large thermal expansion coefficient (for example, a ceramic composite material), and the thermal expansion difference due to the difference in the thermal expansion coefficient can be absorbed. In addition, the turbine disk 12
Since the connecting portion 13 of the compressor shaft 14 and the compressor shaft 14 includes the trapezoidal concave groove 13a and the trapezoidal convex portion 13b fitted therein, a large torque for driving the compressor can be transmitted. In addition, the two surfaces 13 forming the trapezoidal inclined surface
Since c and 13d extend in the radial direction, they are automatically aligned by the movement along the surface, and misalignment is unlikely to occur. Further, the turbine disk 12 and the compressor shaft 14
Since the joint portion 13 of is composed of the trapezoidal concave groove 13a and the trapezoidal convex portion 13b fitted therein, and is fastened by the tie bolt 16, the joint portion 13 can receive a bending moment and enhance the bending rigidity. be able to.

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

[0021]

As described above, in the turbine disk coupling structure of the present invention, materials having greatly different thermal expansion coefficients can be used for the turbine disk, and the difference in thermal expansion due to the difference in thermal expansion coefficient can be absorbed. Therefore, the torque for driving the compressor can be transmitted, misalignment is unlikely to occur, and bending rigidity is high.

[Brief description of drawings]

FIG. 1 is a structural view of a turbine disk according to the present invention.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is a detailed view of a coupling structure according to the present invention.

FIG. 4 is a view showing a coupling structure of a conventional turbine disk.

[Explanation of symbols]

1 compressor 2 Combustor 3 turbine 4 turbine blades 5 turbine disk 5a Flange part 6 rotor 6a Flange part 7 bearings 8 volt 11a outer peripheral part 11b through hole 11c shoulder 12 turbine disk 12a disk body 12b shaft body 13 Connection 13a trapezoidal groove 13b Trapezoidal protrusion 13c, 13d Trapezoidal inclined surface (2 surfaces) 14 Compressor shaft 14a connecting part 14b drive 14c spline 15 Female thread 16 tie bolts 16a Male screw part 16b head 16c spline Z axis center

Claims (4)

[Claims] 1. A turbine disk having a plurality of turbine blades on its outer periphery, a compressor shaft connected to one end of the turbine disk and extending in the axial direction, and a tie bolt screwed to the compressor shaft to fasten the turbine disk to the compressor shaft. Composed of the turbine disk and the compressor shaft,
It is composed of a plurality of trapezoidal concave grooves provided on one side and a plurality of trapezoidal convex portions provided on the other side and fitted into the concave grooves, and the trapezoidal concave groove and the trapezoidal convex portion respectively form a trapezoidal inclined surface. The two surfaces extending in the radial direction are in contact with each other, the turbine disk has a through hole concentric with the axial center and a shoulder portion projecting inward of the through hole, and the compressor shaft has an end on the turbine disk side. Has a female threaded portion concentric with the shaft center, the tie bolt is a hollow cylindrical shape, a male threaded portion provided at one end thereof and screwed into the female threaded portion of the compressor shaft, and a turbine disk provided at the other end. A head portion that projects radially outward from a shoulder portion, hold the tie bolt in a tensioned state by screwing the female screw portion and the male screw portion, and thereby hold the turbine disk by pressing it to the compressor shaft side; A turbine disc coupling structure characterized by the above. 2. The coupling structure for a turbine disk according to claim 1, wherein the tie bolt is made of a niobium alloy, a nickel alloy or a molybdenum alloy. 3. The turbine disk comprises a disk body having the outer peripheral portion and the coupling portion, and a shaft portion having the shoulder portion, and the disk body and the shaft portion each have an axial center at a boundary portion thereof. The coupling structure for a turbine disk according to claim 2, wherein the coupling structures have vertical planes, and the planes are in close contact with each other. 4. The compressor shaft comprises a coupling part coupled to one end of a turbine disk, and a driving part extending axially to the compressor, the coupling part and the driving part being mutually connected by a spline extending axially. The turbine disk coupling structure according to claim 1, wherein the turbine disk coupling structures are connected.