JPH06212905A - Fixed blade in moving blade cascade - Google Patents

Abstract

PURPOSE:To simplify the fixing structure consisting of fixing parts for fixing a fixed blade provided in a rotor so as to form a ring-shaped cascade of moving blades of a steam turbine and located in a notch-groove for receiving a moving blade so that the fixed blade may not fall out due to a centrifugal force caused by the rotation of the rotor. CONSTITUTION:A long hole 12 penetrating through the leg part 7 of a fixed blade 8 in the circumferential direction is provided to reduce the weight of the fixed blade 8, and to reduce a centrifugal force which the fixed blade receives due to the rotation of a rotor. Then the fixed blade is fixed to the rotor 4 only with fixing screws 11 instead of conventionally used fixing pins.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is directed to a rotor blade of a steam turbine, which is provided in a rotor for forming a rotor blade row forming an annular blade row of rotor blades and is located in a notch groove into which the rotor blade is inserted. Regarding fixed wing of a row.

[0002]

2. Description of the Related Art In a steam turbine, moving blades which are implanted in a rotor in an annular blade row and stationary blades which are implanted in a casing surrounding the rotor in an annular blade row form a blade stage, and a steam turbine is formed. Works by rotating the rotor by flowing through this wing paragraph. By the way, the rotor blade row forming the annular blade row of rotor blades is
It is formed as described below. Communicating with the annular blade groove provided in the rotor, the rotor blades are sequentially inserted into the notch groove provided in the rotor so that the legs of the blade can be inserted from the outside, and the rotor blade moves from the notch groove to the annular blade groove. The legs of the wings are inserted to form an annular cascade. Here, the final moving blade forming the annular blade row is fixed to the rotor as a fixed blade at the position of the notch groove by the fixing means, and the moving blade blade row forming the annular blade row is formed.

FIG. 5 is a partial plan view of a rotor blade row forming an annular blade row of the rotor blades on which the above fixed blades are arranged (a view from the arrow A in FIG. 6), and FIG. 6 is a portion BB in FIG. FIG. In FIGS. 5 and 6, the moving blade 1 is composed of a blade portion 2 and a leg portion 3, and the leg portion 3
Are sequentially inserted from the notch groove provided in the rotor 4 into the blade groove that communicates with the rotor 4, and are arranged in an annular shape through the caulking piece 5, and the fixed blade 8 including the blade portion 6 and the leg portion 7 is arranged in the notch groove. Form a rotor blade cascade forming an annular blade cascade of rotor blades. The fixed blade 8 is fixed to the rotor 4 around the leg 7 by a fixing pin 10 which is driven obliquely at a position in contact with the leg 3 of the moving blade 1, and at a position in contact with the rotor 4 by a fixing screw 11 at a position in contact with the rotor 4. .

With this structure, the fixed blade 8 is fixed by the fixing pin 10 and the fixing screw 11, so that even if the rotor 4 rotates, the fixed blade 8 does not fall out due to the centrifugal force.

[0005]

In the structure of the conventional fixed blade, in order to prevent the rotor from coming off due to centrifugal force during rotation of the rotor, the number of fixing parts such as fixing pins and fixing screws is increased, and the fixing parts are fixed. There is a drawback that it is necessary to increase the size of. An object of the present invention is to provide a fixed blade of a moving blade cascade that can simplify a fixing structure including a fixed component that fixes the fixed blade.

[0006]

In order to solve the above-mentioned problems, according to the present invention, the legs of the moving blade are sequentially inserted from the notch groove provided in the rotor of the steam turbine into the annular blade groove following this groove. Then, the rotor blades are annularly arranged, and the rotor blades are arranged in the notch groove and fixed to the rotor by the fixing means.
The fixed blade shall be provided with a reducing means for reducing the centrifugal force generated when the rotor rotates.

The above-mentioned reducing means is provided with holes in the leg portions of the fixed wing.

[0008]

The fixed blade, which communicates with the annular blade groove provided in the rotor and is located in the notch groove into which the leg portion of the moving blade is inserted, is provided with a reducing means for reducing the centrifugal force due to the rotation of the rotor. By providing the holes in the legs of the fixed blade, the weight of the fixed blade is reduced, so that the centrifugal force received by the fixed blade is reduced. Therefore, it is possible to simplify the fixing structure such as reducing the number of fixing parts for fixing the fixed blades.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a partial cross-sectional view of a rotor according to an embodiment of the present invention in which fixed blades are fixed and implanted (partial cross-sectional view taken along the line D-D of FIG. 2), and FIG. It is a partial top view of a moving blade cascade. 1 and 2, the same parts as those of the conventional example of FIGS. 5 and 6 are designated by the same reference numerals, and the description thereof will be omitted. 1 and 2 are different from the conventional example in that the leg portion 7 of the fixed blade 8 is provided with an elongated hole 12 penetrating in the circumferential direction to reduce the weight, and the fixed blade 8 is fixed on both sides of the leg portion 7 with fixing screws 11 It is fixed to the rotor 4 only by itself.

With such a structure, the fixed wing 8 is connected to the leg 7
Even if the rotor 4 is fixed to the rotor 4 on both sides with only the fixing screw 11, the centrifugal force due to the rotation of the rotor 4 is reduced, so that the stationary blade 8 does not fall out by this centrifugal force. FIG. 3 is a partial cross-sectional view of a rotor in which fixed blades are fixed and implanted according to another embodiment of the present invention (F-F partial cross-sectional view of FIG. 4), and FIG.
FIG. 7 is a partial plan view of a rotor blade cascade including fixed blades as viewed from the arrow E of FIG. 3 and 4, it is the same as that shown in FIGS. 1 and 2, except that the leg portions 7 of the fixed blade 8 are provided with circular holes 14 and 15 penetrating in the circumferential direction.

With this structure, the same effect as described above can be obtained by fixing the fixed blade 8 with the fixing screw 11 as described above.

[0012]

As is apparent from the above description, according to the present invention, the weight of the fixed blade is reduced by providing the fixed blade with a reducing means for reducing the centrifugal force. Since the centrifugal force due to the rotation of the rotor is reduced, the number of fixing parts can be reduced or reduced, and the fixing structure can be simplified.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view taken along the line DD of FIG. 2 showing a rotor with fixed blades fixedly implanted according to an embodiment of the present invention.

FIG. 2 is a partial plan view of a rotor blade row including fixed blades as viewed from the direction of arrow C in FIG.

FIG. 3 is a partial cross-sectional view taken along line F-F of FIG. 4 showing a rotor with fixed blades fixedly implanted according to a different embodiment of the present invention.

FIG. 4 is a partial plan view of a rotor blade cascade including fixed blades as viewed from the direction of arrow E in FIG.

FIG. 5 is a partial plan view of a rotor blade row including a conventional fixed blade as viewed in the direction of arrow A in the diagram shown in FIG.

6 is a partial cross-sectional view taken along the line BB of FIG.

[Explanation of symbols]

 1 Moving Blade 2 Wing Part 3 Leg Part 6 Wing Part 7 Leg Part 8 Fixed Wing 11 Fixing Screw 12 Long Hole 14 Round Hole 15 Round Hole

Claims (2)

[Claims] Claim: What is claimed is: 1. A rotor blade is arranged in a notch groove by inserting the leg portions of the rotor blade from a notch groove provided in a rotor of a steam turbine into an annular blade groove following the groove in order. A fixed blade of a moving blade cascade fixed to a fixed blade of the moving blade cascade, wherein the fixed blade is provided with a reducing means for reducing a centrifugal force generated when the rotor rotates. 2. The fixed blade of a moving blade cascade according to claim 1, wherein the reducing means has holes in the legs of the fixed blade.