JPH04134603U - turbine blades - Google Patents

Abstract

(57) [Summary] [Purpose] The purpose is to have a high degree of coupling between each shroud and to obtain a sufficient vibration damping effect. [Structure] The shroud has a tapered surface that contracts inward and is fixed to the rotor, and the shroud has a tapered surface that contracts outward parallel to this tapered surface and can be moved outward by centrifugal force. The blades are attached to the rotor and are adjacent to each other.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention applies to turbines such as steam turbines and gas turbines that are applied to thermal power generation. Regarding moving blades.

0002

[Conventional technology]

Figure 3 shows the structure of a rotor blade of a steam turbine with a conventional integral shroud. It is a diagram. In the figure, the main rotor blades include shroud 1, blade (profile) 2, and blade root 3. The blades are integrally formed, and each rotor blade is independently attached to the rotor. As it is, multiple rotor blades are connected together through one shroud. Compared to group rotor blades, the natural frequency is lower and the vibration damping effect is also lower. others Therefore, as an example of a means for increasing the vibration-proofing effect, one screw plate is installed adjacent to the three normal blades 2A. The blades 2B are equipped with rotating blades or blades 2B with different torsion amounts, and centrifugal force and bending force are generated during operation. Due to the twist back, the shroud 1B end face of the blade 2B is adjacent to the The shroud 1A of the blade 2A comes into pressure contact with the end surface of the shroud 1A, and the shroud 1 of the entire circumference is connected to each other. It looks like this.

0003

[Problem that the idea aims to solve]

However, with the pressure welding structure of shroud 1 using the twist back as described above, The degree of coupling between the shrouds 1 is low, and the vibration damping effect cannot be said to be sufficient.

0004

[Means to solve the problem]

The turbine rotor blade according to the present invention aims to solve the above problems, and the shroud a first wing fixed to the rotor and having a tapered surface that contracts inward; If the adjacent shroud has a tapered surface that decreases outward parallel to the tapered surface, Both blades are equipped with second blades that are freely attached to the rotor so as to be movable outward by centrifugal force. It is characterized by a unique configuration.

[0005]

[Effect]

That is, in the rotor blade of the turbine according to the present invention, the shroud is inwardly contracted. The blades and shroud fixed to the rotor have a tapered surface parallel to this tapered surface. It has a tapered surface that contracts outward and can be moved outward by centrifugal force. The blades attached to the rotor are adjacent to each other, and the blades attached to the rotor are attached to the rotor when the turbine is operating. The shroud moves outward due to centrifugal force and the shroud of the adjacent wing and the tapered surfaces are pressed against each other by high surface pressure and are connected to each other. Therefore, each shrou The degree of coupling between codes is high.

[0006]

【Example】

Figure 1 is an explanatory diagram of the structure of a rotor blade of a steam turbine according to an embodiment of the present invention, and Figure 2 is an illustration of its operation. It is an explanatory diagram. In the figure, the rotor blades of the steam turbine according to this example are used for thermal power generation. A rotor blade with an integral shroud for a steam turbine, as shown in Figure 1. Sea urchin shroud 1, wing (profile) 2, wing root 3, etc. are integrally formed. At the same time, each rotor blade is independently attached to the rotor 4, and as it is, multiple rotor blades are installed. Compared to group rotor blades, where two blades are connected together through one shroud. It has a low natural frequency and low vibration damping effect. Therefore, the main rotor blade is connected to each adjacent blade 2. A tapered tapered outward as a means of coupling the shroud 1 of the The wings 2c of the shroud 1C have a shroud 1C, and the shroud has an inwardly tapered The shrouds 1D and 2D are alternately attached to the rotor 4, and each shroud 1c, A gap S1 is provided between 1d. In addition, the blade root 3C of shroud 1C is bare It is installed with a radial gap S2 between the blade groove of the rotor 4 and the blade groove of the rotor 4. Ru. The taper angle α of the shrouds 1c and 1d is 45 degrees with respect to each other.

[0007] During operation of the steam turbine, the blades 2c are rotated by the blade roots 3c due to centrifugal force as shown in FIG. floats outward in the blade groove, and the tapered surface of shroud 1C that protrudes is adjacent to it. It is pressed against the tapered surface of the shroud 1D. As a result, the shura of each wing 2C, 2D The shrouds 1c and 1d are connected to each other by high contact pressure on the tapered surfaces, and the shroud is formed around the entire circumference. The degree of coupling between the first and second leads has been improved, and the vibration damping effect is sufficiently high, increasing the reliability of the steam turbine. Improves sex.

[0008]

[Effect of the idea]

The rotor blades of the turbine according to the present invention are constructed as described above, and there is a gap between each shroud. Since the degree of coupling is high, a sufficient vibration damping effect can be obtained.

[Brief explanation of drawings]

FIG. 1(a) is a side view of a rotor blade of a steam turbine according to an embodiment of the present invention, and FIG. 1(b) is a view taken along line bb in FIG. 1(a).

FIG. 2 is an explanatory diagram of its operation.

FIG. 3 is a plan view of a rotor blade of a conventional steam turbine.

[Explanation of symbols]

1, 1C, 1D shroud 2, 2C, 2D wings 3,3C,3D wing root 4 Rotor S1 Shroud gap S2 Wing root gap α Taper angle E Bearing surface

Claims (1)

[Scope of utility model registration request] Claims: 1. A first wing fixed to a rotor having a tapered surface that contracts inwardly on a shroud, and a tapered surface adjacent to the wing that contracts outwardly in parallel to the tapered surface on the shroud. and a second blade loosely attached to the rotor so as to be movable outward by centrifugal force.