JPH074202A - Connecting device for turbine moving blade - Google Patents

Abstract

PURPOSE:To provide a turbine moving blade connecting device which can be effectively combined with a saddle type embedding structure of a turbine moving blade. CONSTITUTION:An embedding part for fitting turbine moving blade is formed in the outer periphery of a turbine rotor and a base part of a turbine moving blade 22 is fitted to the embedding part through a cut-out part provided in the embedding part. The turbine moving blades 22 are moved in the peripheral direction to arrange the multiple turbine moving blades 22 in the outer periphery of the turbine rotor, and thereafter a stopping blade 27 is connected to the cut-out part. Bosses are formed on blade surface of the multiple turbine moving blades opposed to each other, lugs projecting in the boss axis direction are provided at both ends of the boss, and mutually adjoining turbine blades 22 are connected to each other by a sleeve interposingly fitted to the lug. The stopping blade 27 is provided with a lug 29, which is connected to a lug 31 of the adjoining turbine moving blade 22 via a sleeve 32 through movement in the radial direction. Length in the axial direction of the sleeve 32 interposingly fitted to the lug 29 of the stopping blade 27 is made shorter at a tip side than at a base side of the blade 27.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turbine rotor blade connecting device, and more particularly to a turbine rotor blade connecting device capable of effectively suppressing vibration of the turbine rotor blade during operation.

[0002]

2. Description of the Related Art Since an excessive centrifugal force acts on a turbine rotor blade at a high speed, it is taken into consideration when designing the turbine that the stress of each portion of the turbine rotor blade has a sufficient margin with respect to the allowable stress of the material. . However, as the capacity of turbines has been increased, turbine blades have been made longer, and in particular, long blades such as low-pressure final blades have been designed so that there is not enough room for the material strength locally. There is.

When designing a long blade turbine blade, it is generally designed that the natural frequency does not match an integral multiple of the rotational speed at the rated rotational speed, but if the turbine is frequently started and stopped. When the rotation of the blade rises or falls, the natural frequency and the rotation frequency component match each other and resonate, which may cause a large vibration stress on the blade. In operation under a low load condition, vortex or turbulence of the flow due to separation of the flow of the driving fluid acts on the turbine rotor blade as an exciting force, so that the vibration stress of the turbine rotor blade is increased.

In particular, since the turbine blade on the low pressure last stage blade side is a long blade, it is unavoidable that it is exposed to a severe environment from both static stress and vibration stress.

As a method of reducing the vibration of the turbine rotor blade, there is a turbine rotor blade coupling device in which a through hole is provided in the steam passage intermediate portion of each blade and adjacent rotor blades are connected to each through hole through a tie wire. . In this case, the vibration of the turbine rotor blade is suppressed by utilizing the surface friction generated between the tie wire and the inner surface of the through hole by the centrifugal force acting on the tie wire.

On the other hand, since the centrifugal force acting on the turbine rotor blade is received by the implanting portion of the rotor blade, the structure of the implanting portion also depends on the blade length of the turbine rotor blade, the degree of the above centrifugal force, the ease of assembly work, and the like. For consideration, fork type, tree type, saddle type, etc. are considered. Among them, the saddle type implant structure is particularly excellent in terms of easiness of forming the turbine rotor blade and wheel, easiness of assembling, and high precision of the shape.

FIG. 9 shows a turbine blade connecting device which is a combination of a turbine blade connecting with a tie wire and a saddle type implant. The turbine rotor blade 1 is fitted to a stud 4 provided on the outer periphery of a wheel 3 as a turbine rotor via a saddle-shaped base 2 provided at the base thereof. A wire hole 5 is formed in the blade intermediate portion of the turbine rotor blade 1, and a tie wire 6 penetrates the wire hole 5.
A shroud cover (not shown) may be attached to the tip of the turbine rotor blade 1 in order to adjust the frequency of the turbine rotor blade 1 and suppress leakage steam.

FIG. 10 shows the insertion portion (notch portion 7) of the moving blade 1 in the implantation portion 4 of the wheel 3, and FIG. 11 shows the assembled state. A notch 7 is formed on the outer circumference of the wheel 3 at one position in the circumferential direction, and the tie wire 6 is wound in advance along the circumferential direction of the wheel 3.

As shown in FIG. 11, first, the turbine rotor blade 1 is inserted at the position of the notch 7 toward the axis of the wheel 3 (direction of arrow C), and the base 2 is cut at the notch 7. It is incorporated in the implant part 4 of the wheel 3. Next, in the clearance CT, the tie wire 6 is penetrated through the wire hole 5,
Then, the moving blade 1 is moved to the designated position on the outer circumference of the wheel 3 clockwise (direction of arrow D) or counterclockwise (direction of arrow E).

As shown in FIG. 12, the tie wire 6 is divided into a plurality of pieces along the circumferential direction of the wheel 3 (FIG. 12).
The tie wire spacing is indicated by CW). Note that the configurations of the turbine rotor blade 1 and the wheel 3 are omitted in FIG. Stoppers 8 are provided at both ends of each tie wire 6. Assembling the turbine blade 1
This is performed for each tie wire 6, and a blade group of the turbine rotor blade 1 is formed according to the number of tie wires. The number of blade groups is selected mainly according to the vibration characteristics of the turbine rotor blade 1.

In this way, the turbine rotor blade 1 is entirely arranged on the entire circumference of the wheel 3 except the cutout portion 7, and then the stop blade is inserted into the cutout portion 7. FIG. 13 shows a completed assembled state of the turbine rotor blade 1. As shown in FIG.
Is fixed to the wheel 3 by a stop pin 10 and a stop key 11.

By the way, with the increase in base load operation of nuclear power generation in recent years, even a relatively large-capacity thermal power turbine is often used for load adjustment of electric power. The thermal power turbine for load adjustment is subjected to an operation of frequently starting and stopping on a daily basis (hereinafter referred to as a DSS operation), a load adjustment that is significantly below the design point of the turbine, and the like.
When the above load adjustment operation is performed in a turbine blade connecting device using tie wires, corrosive substances contained in the working steam that are in a wet state adhere to the turbine blade when the above load adjustment operation is performed, especially near the final stage where the environment is exposed to low pressure. And the fatigue strength of the rotor blade material is reduced, which in turn is promoted by the vibration stress generated in the turbine rotor blade, causing corrosion fatigue failure. In particular, in the turbine blade connecting device using the tie wire, there is a problem that the corrosive substance is likely to be deposited between the wire hole 5 and the tie wire 6. Furthermore, stress concentration is likely to occur around the wire hole 5.

In order to solve such a problem, as another typical example of reducing the vibration of turbine rotor blades, Japanese Examined Patent Publication No. 52-
There is a turbine blade connecting device described in Japanese Patent No. 18841. As shown in FIG. 14, this connecting device forms bosses 12 on the opposing blade surfaces of turbine rotor blade 1, and further bosses 1
Protrusions (hereinafter referred to as lugs) 13 are provided on the two lugs, and the opposing lugs 13 are connected to each other in a tubular shape (hereinafter referred to as sleeve) 1
4 and connects adjacent turbine moving blades 1 to each other. Also in this coupling device, the surface friction between the lug 13 and the sleeve 14, which is generated by the centrifugal force acting on the sleeve 14, suppresses the vibration of the turbine rotor blade 1. Further, according to this coupling device, an effective vibration characteristic is obtained in which the response is extremely small with respect to the excitation of the vibration mode in the tangential direction of the outer periphery of the wheel 3 due to the forced external force, and further the wire hole 5 It is also possible to find the advantage of no stress concentration and no deposition of corrosive substances.

[0014]

However, the above-mentioned lug sleeve coupling device has a problem that it is not compatible with the saddle type implant structure. That is, in the saddle type implant structure, a normal turbine blade can be moved in the circumferential direction so that it can be moved due to the mounting of the sleeve, while the retaining blades can be moved in the circumferential direction because the turbine blades on both sides are fixed. I can't. Therefore, conventionally, a sleeve cannot be inserted in the stop blade, and the turbine blade cannot be integrated with the lug sleeve. When the saddle type implant structure is adopted as described above, it is difficult to use the lug sleeve connecting device, and there is a problem that the advantages of the lug sleeve connecting cannot be obtained.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a turbine blade connecting device that can be effectively combined with a saddle-type implant structure for turbine blades.

[0016]

In order to achieve the above-mentioned object, the present invention forms an implanting portion for mounting a turbine rotor blade on the outer periphery of a turbine rotor, and uses the notch provided in the implanting portion to form the turbine moving member. The base of the blade is attached to the implanting part, the turbine moving blade is moved in the circumferential direction of the turbine rotor, and a large number of the turbine moving blades are arranged on the outer periphery of the turbine rotor, and then stopped at the notch. A connecting device of turbine moving blades formed by joining blades, wherein bosses are formed on opposing blade surfaces of the plurality of turbine moving blades, and lugs protruding in the boss axial direction are provided at both ends of the boss, In a case of connecting the turbine moving blades adjacent to each other with a sleeve interposed in the lugs, a lug is provided on the stop blade, and the lug of the stop blade is adjacent to the turbine moving blade. Wherein the the lug linked to at the sleeve by radial movement.

In the present invention, it is desirable that the axial length of the sleeve inserted in the lug of the stop blade be shorter on the tip side of the blade than on the base side of the blade.

In the present invention, the turbine rotor blade adjacent to the stop blade is provided with a lug having a different height with respect to the blade surface, and the height of the lug is made lower on the blade tip side than on the blade base side. Is desirable.

[0019]

In the present invention, the turbine rotor blade is inserted toward the axis of the wheel at the position of the cutout portion, and the base portion of the rotor blade is incorporated in the wheel implantation portion at the cutout portion. Then, the turbine blade moves clockwise or counterclockwise on the outer circumference of the wheel to a specified position, and a sleeve is attached to the lug and the lug of the adjacent turbine blade to connect the blades to each other.

Finally, the stopper blades are inserted toward the shaft center of the wheel in the notches sandwiched between the turbine rotor blades on both sides. The stop vane is fixed to the wheel with a stop pin and a stop key, and a sleeve is radially connected to the stop blade lug and the adjacent turbine rotor blade lug to complete the assembly.

In the case of setting the difference in the axial length of the sleeve and the height difference of the seating surface of the adjacent lugs as a structure in which the lugs of the stop blades are moved in the radial direction of the wheel with respect to the lugs of the adjacent turbine blades. The sleeve can be easily fixed to the lug by inserting the stopper blade toward the wheel axis.

As described above, according to the present invention, the turbine rotor blades can be connected by the lug sleeve even if the turbine rotor blades are saddle-shaped.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a turbine blade connecting device according to the present invention will be described below with reference to FIGS.

FIG. 1 shows a turbine impeller equipped with a turbine blade connecting device according to the present invention. This turbine impeller includes a base portion 23 of a turbine rotor blade 22 on an outer peripheral portion of a wheel 20 serving as a turbine rotor via an implanting portion 21.
Is to be fitted. A boss 24 is formed on the blade surfaces of the turbine rotor blade 22 that face each other, and a lug 25 is provided at the tip of the boss 24. Sleeve 2 between opposing lugs 25
6 are fitted together, and adjacent turbine moving blades 22 are connected to each other by this sleeve 26.

FIG. 2 is a sectional view showing the stopper blade 27 and the turbine rotor blades 22 on both sides thereof when the sleeve is mounted. A boss 28 is provided in the center of both blade surfaces of the stop blade 27, and a lug 29 projects in the axial direction of the boss 28. Figure 2
In, the stop blade 27 is displaced radially outward from the assembled position by a width of ΔR. On the other hand, as shown in FIG. 3, the turbine rotor blade 22 adjacent to the stopper blade 27 is provided with a boss 30 at the blade central portion facing the stopper blade 27, and the boss 30 has a lug 31 protruding in the axial direction thereof. Each is provided. The boss 30 and the lug 31 are formed integrally with the turbine rotor blade 22.

FIG. 4 is a view on arrow B in FIG. Rug 3
The axial length of the seat of 1 is ΔC on the tip side of the wing than on the base side.
Therefore, when the turbine rotor blade 22 is erected upright, the bearing surface of the lug 31 is slightly inclined with respect to the blade surface.
Although ΔC is provided by inclining from the center of the bottom surface of the lug 29 to the blade tip side in FIG. 4, ΔC may be provided by inclining the entire bottom surface of the lug 29 as shown in FIG.

A sleeve 32 connecting the stop vane 27 and the turbine rotor blade 22 is shown in FIGS. 6 and 7. Figure 6
(A) is an axial side view of the sleeve 32, and (B) is a longitudinal sectional view thereof. Assuming that the axial length of the sleeve 32 located radially inside the wheel 20 is LR and the length located outside thereof is LT, LR> LT, that is, LT = LR-.
2CS, and the axial length is gradually reduced from the centerline position of the sleeve 32. However, FIG. 7 (A), (B)
As shown in, the axial length may be reduced from the inner side in the radial direction to the outer side as a whole.

FIG. 8 shows a state in which the stopper blade 27 is moved by ΔR in the axial direction of the wheel 20 (direction of arrow A in FIG. 2) from the state shown in FIG. 2 to complete the assembly. In this way, the stop blade 27 is movably connected to the adjacent turbine rotor blade 22 via the sleeve 32.

The axial length L of the sleeve 32 is L.
If T is too small, the sleeve 32 may fall off the lugs 29 and 31. Therefore, in this embodiment, the lug 3
The relationship between the length LO of the sleeve 32 fitted to 1 and the clearance CB between the lug 29 and the sleeve 32 is LO>
CB is provided to prevent the sleeve 32 from falling off.

Next, the operation of this embodiment will be described.

Since the stopper wing 25 is assembled last,
As described above, the circumferential movement of the wheel 20 is restricted by the adjacent turbine moving blades 22, and the wheel 20 can be moved only in the radial direction. In the past, it was not possible to insert the retaining wings between the opposing lugs, and the assembly of the retaining wings became unstable, making it difficult to mount them, whereas in the present embodiment, the shaft of the sleeve 32 is The direction length is set to LR> LT, and the height of the lug 29 with respect to the seating surface is made lower on the tip side of the blade than on the base side of the blade, so that the stop blade 27 is attached to the turbine rotor blades 22 on both sides of the blade 20. Since it can be locked by the directional movement, the turbine moving blade 22 can be easily and surely connected to the wheel 20 including the stop blade 27.

[0032]

As described above, according to the present invention, in the saddle type implanting structure of the turbine rotor blade, the retaining blade can be connected to the turbine rotor blade by the lug sleeve, and the steady excitation by the turbine lug sleeve connecting device is performed. Characteristics and damping effect on harmonic excitation force due to force and rotor speed, corrosion inhibition effect, and characteristics such as ease of forming turbine turbine blades and wheels due to saddle type implant structure, ease of assembly, high precision of shape, etc. Can be realized at the same time, and thus the excellent effects such as the reliability of the turbine wheel can be improved.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of a turbine blade connecting device according to the present invention.

FIG. 2 is a cross-sectional view showing the stop blade and the turbine blades on both sides thereof when the sleeve of the turbine blade connecting device is mounted.

FIG. 3 is a plan view showing the shape of a turbine rotor blade.

FIG. 4 is an enlarged view showing a lug in a B direction arrow view of FIG. 3;

FIG. 5 is a diagram showing another configuration example of a lug.

FIG. 6A is a side view of the sleeve, and FIG. 6B is a vertical sectional view of FIG.

FIG. 7A is a diagram showing another configuration example of the sleeve,
(B) is a longitudinal sectional view of (A).

FIG. 8 is a cross-sectional view of an essential part showing a retaining blade that has been assembled.

FIG. 9 is an explanatory view showing a turbine blade connecting device in a conventional example.

FIG. 10 is a perspective view showing a cutout portion formed in a wheel in a conventional example.

FIG. 11 is an explanatory view for explaining assembly of a turbine rotor blade in a conventional example.

FIG. 12 is an explanatory view showing the arrangement of tie wires in a conventional example.

FIG. 13 is an explanatory view showing a state in which the assembly of the stopper blade in the conventional example is completed.

FIG. 14 is an explanatory view showing a turbine blade connecting device in a conventional example.

[Explanation of symbols]

 20 Turbine rotor (wheel) 21 Implantation part 22 Turbine rotor blade 23 Base part 24, 28, 30 Boss 25, 29, 31 Lug 26, 32 Sleeve 27 Stopper blade

Claims (3)

[Claims] 1. A turbine rotor blade mounting portion is formed on an outer periphery of a turbine rotor, and a base portion of the turbine blade is mounted to the implantation portion from a notch provided in the implantation portion and the turbine rotor blade is mounted. In the circumferential direction of the turbine rotor, and after arranging a large number of the turbine moving blades on the outer periphery of the turbine rotor, a connecting device for turbine moving blades, comprising joining stop blades to the notches. , Forming bosses on the opposing blade surfaces of the many turbine rotor blades,
In addition to providing lugs protruding in the boss axial direction at both ends of the boss, and connecting the turbine moving blades adjacent to each other with a sleeve interposed in the lug, while providing lugs in the stop blade, A turbine blade connecting device, wherein a lug of a stop blade is connected to an adjacent lug of the turbine blade via a sleeve by radial movement. 2. The turbine blade according to claim 1, wherein the axial length of the sleeve interposed in the lug of the stop blade is shorter on the tip side of the blade than on the base side of the blade. Coupling device. 3. A turbine rotor blade adjacent to the stop blade is provided with a lug having a different height with respect to the blade surface, and the height of the lug is made lower on the tip side of the blade than on the base side of the blade. The turbine blade connecting device according to claim 1.