JP2011074806A - Fixing structure of turbine moving blade - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing structure of a turbine moving blade, which suppresses a local stress or stress corrosion cracking generated on the lifting components of a moving blade, and prevents the moving blade from slipping off. <P>SOLUTION: The fixing structure of the turbine moving blade includes a plurality of lifting members 10, 11 provided with recessed portions in the middle in an axial direction on inner surface sides of an insertion groove 4 and a groove portion 6, and having tapered surfaces on one end side in the axial direction; and a slip-off preventive components 12, 13 formed with tapered surface engaged with the tapered surfaces of the lifting members on both end sides in the axial direction, and projecting portions fitted with the recessed portions on the inner surface sides of the insertion groove and the groove portion. The lifting components are inserted in a clearance 7 formed between the insertion groove and the groove portion from both directions, and the tapered surfaces of the lifting components are engaged with the tapered surfaces of the lifting components to lift up the lifting components in a diametrical direction, thereby making the projecting portions of the slip-off preventive components fit with the recessed portions formed on the inner peripheral surfaces of the insertion groove and the groove portion. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a turbine rotor blade fixing structure in which a rotor blade root is inserted and fixed in a groove provided in a rotor.

  Turbine blades inserted in the direction of the rotation axis with respect to the grooves provided in the rotor that rotates the rotor blade root are pressed against the grooves provided in the rotor by its own centrifugal force during rotation. Fixed. The method of fixing the turbine blade in the groove provided in the rotor by centrifugal force indicates that the blade is not sufficiently fixed at the time of low rotation with small centrifugal force. Therefore, by inserting shims and wedges between the turbine rotor blade and the rotor groove, the turbine rotor blade can be fixed to the rotor groove even at a low rotation speed.

  In addition, as a prior art regarding the fixing structure of the turbine rotor blade with respect to a rotor, there exists a technique of patent document 1, for example.

JP 2008-88832 A

  In order to fix the turbine rotor blade to the rotor groove in the turbine rotor blade inserted in the rotor groove portion provided in the rotor axial direction on the outer periphery of the rotor, a push-up structure is provided at the lowermost part of the turbine rotor blade to fix the turbine rotor blade to the rotor groove. It is known to insert, but when a wedge-shaped insertion part is adopted, the groove, rotor groove or push-up part provided on the turbine rotor blade becomes a point contact or line contact and becomes a local high stress part. There was a risk of deformation and cracking due to stress corrosion cracking when operated for a long time. It has also been desired to make sure that the moving blades come out in the axial direction.

  Accordingly, an object of the present invention is to provide a turbine blade fixing structure that suppresses local stress and stress corrosion cracking generated in the moving parts of the moving blade and prevents the moving blade from coming out.

  In order to achieve the above object, a turbine rotor blade fixing structure according to the present invention includes a turbine rotor blade fixing structure in which a blade root portion is inserted into a groove provided in an outer peripheral portion of a turbine rotor to fix the turbine rotor blade. An insertion groove extending in the axial direction is formed on the distal end side in the inner diameter direction of the blade root portion, a recess is provided in the axial direction on the inner surface side of the insertion groove and the groove portion, and a tapered surface is provided on one end side in the axial direction. A retaining component in which a plurality of push-up members, tapered surfaces that engage with the taper surface of the push-up member on both ends in the axial direction, and convex portions that fit into the concave portions are formed on the inner surface side of the insertion groove or the groove portion. The push-up component is inserted into the gap formed by the insertion groove and the groove portion from both directions, and the taper surface of the push-up component is engaged with the taper surface of the push-up component so that the push-up component is radially The convex part of the retaining part Characterized by being configured to mate with the insertion groove and the inner circumferential surface recess formed in the groove.

  According to the present invention, it is possible to provide a turbine rotor blade fixing structure that can reduce local stress generated in a push-up component of a rotor blade and more reliably prevent the rotor blade from coming off.

The figure which showed the Example of this invention. The figure which inserted the turbine rotor blade in the turbine rotor. The expanded sectional view of the insertion part of a turbine rotor. The figure which shows the force which acts on raising parts. FIG. 5 is a diagram showing the relationship between the angle of the end face where the push-up component does not protrude in the insertion direction and the friction coefficient.

  An embodiment of the present invention will be described with reference to FIGS. The turbine of the present embodiment includes a turbine rotor 5 having a plurality of grooves 6 provided at intervals in the turbine rotation direction on the outer peripheral portion, and a plurality of blade root portions 3 inserted from the turbine axial direction into the grooves 6. A turbine rotor blade 1. Usually, the turbine rotor is configured by providing a plurality of such configurations in the turbine axial direction.

  The turbine rotor blade 1 includes a blade portion 2, a blade root portion 3 of the blade portion 2, and the blade root portion 3. In the present example, an integral cover 8 is further formed integrally with the tip of the wing part 2. Further, an insertion groove 4 for inserting a push-up component, which will be described later, is formed along the axial direction at an inner diameter direction end of the blade root portion 3. Each turbine blade 1 is sequentially assembled into a so-called inverted Christmas tree type groove 6 from the turbine axial direction side, and a plurality of turbine blades 1 are attached to the groove 6 in the turbine rotation direction to form an annular blade row.

  When fixing the turbine rotor blade 1 of the present embodiment to the turbine rotor, first, the retaining parts 12 and 13 are inserted into the gap 7 between the insertion groove 4 formed in the blade root portion 3 and the groove portion 6 of the turbine rotor. The retaining parts 12 and 13 have fitting portions that fit into recessed portions 12a and 13a formed in the axial direction (groove) direction on the inner surface side of the insertion groove 4 and the groove portion 6, and are further described later. It has a tapered portion that engages with the parts 10 and 11. In a state in which the retaining parts 12 and 13 are arranged in the gap 7, the push-up parts 10 and 11 whose end portions on the insertion side are tapered are inserted into the insertion groove 4. The push-up parts 10 and 11 are formed at a height smaller than the gap 7 between the insertion groove 4 provided in the lowermost part of the blade root part 3 and the axial groove part 6 provided in the turbine rotor 5. ing. The push-up parts 10 and 11 inserted into the insertion groove 4 have angled taper surfaces engaged with the taper surfaces of the retaining parts 12 and 13 so that the retaining part 12 is in the outer diameter direction and the retaining part 13 is in the inner diameter direction. Push up. In the pushed-out retaining parts 12 and 13, the fitting parts formed on the convex parts are fitted into the concave parts 12 a and 13 a described above. As a result, it is possible to provide a function of preventing the turbine rotor blade from coming off in the insertion direction.

  In this way, the push-up components 10 and 11 are inserted in both directions in the longitudinal direction of the insertion groove 4 to push up the retaining components 12 and 13 in the radial direction, and the radial end surface of the retaining component 12 is the surface of the insertion groove 4. The blade root portion 3 of the turbine rotor blade 1 is pressed against the axial insertion groove 6 provided in the turbine rotor 5 by contact and push-up force. By providing an angled tapered surface on the insertion side end face of the push-up parts 10 and 11, it becomes possible for all parts to come in contact with each other and reduce the susceptibility to stress corrosion cracking due to deformation and increased local stress. It becomes possible.

  FIG. 4 shows the component force of the force acting on the tapered surfaces of the push-up parts 10 and 11. As shown in FIG. 4, the tangential force and the frictional force of the surface to be engaged by the insertion force F act on the engaging tapered surface. If the tangential force is smaller than the frictional force, it indicates that the pushed-up parts 10 and 11 that have been pushed in do not jump out in the anti-insertion direction.

  FIG. 5 shows the relationship between the friction coefficient at which the push-up component does not pop out and the push-up component end face angle. In the case of ordinary steel, the coefficient of friction is about 0.3. In this case, it is possible to prevent the push-up component from coming out by setting the end face angle to 15 ° or less.

  It is possible to make the push-up parts in surface contact with each other by making the end face where the push-up parts engage with each other at an oblique angle with a push-up part having a height that enters the gap between the turbine rotor blade and the rotor groove. It is possible to make the surface engaged with the rotor blade and the rotor groove into a flat surface, and it is possible to reduce the acting stress of the portion where the lifting force acts and to reduce the susceptibility to deformation and stress corrosion cracking. In addition, the angle of the end face that engages the push-up parts is set so that the component force of the frictional force acting on the engaging surface is larger than the component force in the insertion direction of the push-up force, thereby preventing the pull-out prevention structure. This eliminates the need for the omission structure part.

DESCRIPTION OF SYMBOLS 1 Turbine blade 2 Blade part 3 Blade root part 4 Insertion groove 5 Turbine rotor 6 Groove part 7 Gap 8 Integral cover 10, 11 Push-up parts 12, 13 Keep-off parts

Claims (2)

In the turbine rotor blade fixing structure in which the blade root is inserted into a groove provided on the outer periphery of the turbine rotor to fix the turbine rotor blade,
Forming an insertion groove extending in the axial direction on the tip end side in the inner diameter direction of the blade root part, and providing a recess in the insertion direction of the insertion groove and the inner surface side of the groove part in the axial direction;
A plurality of push-up members having a tapered surface on one end side in the axial direction;
A taper surface that engages with the taper surface of the push-up member on both end sides in the axial direction, and a retaining part in which a convex portion that fits the concave portion is formed on the inner surface side of the insertion groove or the groove portion,
The push-up component is inserted into the gap formed by the insertion groove and the groove portion in both directions, the taper surface of the push-up component is engaged with the taper surface of the push-up component, and the push-up component is pushed up in the radial direction. A fixing structure for a turbine rotor blade, wherein the convex part of the retaining component is configured to be fitted to the insertion groove and a concave part formed on the inner peripheral surface of the groove part.   The turbine blade fixing structure, wherein an angle of the taper surface of the push-up component and the retaining component with respect to the axial direction is 15 degrees or less.

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