RU2328601C1 - Gas turbine rotor disks joint - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: gas turbine rotor disks joint is intended for high-temperature gas turbines to fasten a covering disk all along the main disk rim. The aforesaid joint comprises coupling annular ledges of the disks, one of which being an external member and the other one making an internal member, and the fixing elements made in the form of rods with a head. The external ledge is located on the main disk, while the internal ledge is arranged on the covering disk. The external ledge has, on its free end face, recesses separated by walls with their surfaces provided with grooves to receive the said rods, the said groove being made on the disks axis side arranged along the circumference. The internal ledge is arranged with a radial clearance inside the external ledge and incorporates the radial thorns fitted in the external ledge every other. Grooves of the external ledge are closed by the internal ledges on the disks axis side. Every rod in its groove cane be locked by the thorn head in the recess. The rod end extending from the groove to the recess without the thorn is bent up.

EFFECT: higher-strength disks joint thanks to lower deformation.

5 dwg

Description

The invention relates to the field of engineering, in particular to the disk connections of the rotor of a high-temperature gas turbine, and is intended for fixing the cover disk along the rim of the main disk. The connection can be used in gas turbine engines of aircraft, marine and land vehicles, as well as in power plants.

Known are the disk connections of the rotor of a gas turbine, including the connected ring protrusions of the disks, one of which is female and the other male (Pat. RF No. 2183747, class F01D 5/08, published. 06/20/02; Maslennikov MM, Shalman Yu .I. Aviation gas turbine engines. - M.: Mechanical Engineering, 1975, p. 444). The covering protrusion is located on the rim of the main disk, the male - on the rim of the cover. The protrusions are connected by engagement. However, such engagement does not fully fix the cover disk on the main one, but only excludes its free movement in the radial and axial directions. In this case, the rotor design provides for additional fastening — fixing the cover disk at the main hub using either radial pins or a spike-groove connection made with an interference fit. In addition, the connection through the engagement of the protrusions does not ensure the tightness of the cavity formed between the cover and the main disc.

Known is selected as a prototype, the connection of the disks of the rotor of a gas turbine, including the connected annular protrusions of the disks, one of which is covering, and the other is covered, as well as fixing elements (Vyunov S.A. et al. Design and engineering of aircraft gas turbine engines. - M.: Engineering, 1989, p. 195, fig. 4.48, var. A). Each of the protrusions along the free edge has radial openings. The locking elements, in the form of cylindrical pins, designed to fix the disks relative to each other in the axial and circumferential directions, are installed with an interference fit in the holes. The connection is designed with a guaranteed interference fit on the mating cylindrical belts of the annular protrusions and provides a change in interference with a change in the rotor operating modes (in terms of speed and temperature state of the disks), which does not go into the gap. This connection is one-piece, which complicates the repair of the rotor. In addition, an important disadvantage of this connection is that if it is used to fix the cover disk along the rim of the main one, it has a negative effect on the strength reliability of the disks at the points of their connection. During operation, due to differences in the mass and thermal state of the disks, fatigue cracks are formed on their annular protrusions, leading to destruction.

The objective of the invention is the creation of a detachable connection for fixing the cover disk along the rim of the main, providing high strength reliability of the disks in the places of their connection by reducing the level of deformation processes in the conditions of operation of the turbine.

The problem is solved in that in the connection of the disks of the rotor of a gas turbine, including the connected annular protrusions of the disks, one of which is female, the other is male, and the locking elements, according to the invention, the female protrusion is located on the main disk, male - on the cover, the locking elements are made in in the form of rods with a head, while covering the protrusion from the end of the free edge is equipped with recesses, separated by walls, on the surface of which from the axis of the disks are formed in the circumferential the direction of the grooves for the rods, and the male protrusion is placed with a radial clearance inside the female protrusion and is equipped with radial spikes installed in the recesses of the female protrusion, through one, the grooves of the female protrusion being closed from the axis of the disks by the male protrusion, and each of the rods in its corresponding groove is installed with the possibility of locking it with the thorn head in the recess, and the end of the rod protruding from the groove into the recess free from the spike is bent.

The presence of a radial clearance between the male protrusion and the female protrusion, as well as the execution of radial spikes on the first one and the second notches for the spikes, allow the cylindrical belt of the male protrusion in contact with the cylindrical belt of the female protrusion to freely increase its diameter when the turbine is heated. This possibility, in the case of using a new connection for fixing the cover disk along the rim of the main one, provided that the female protrusion is located on the main disk, and the male on the cover disk, is extremely valuable, because in small modes, the exhaust of the cover disk is more intense than the main one. In contrast to the prototype, where there is an interference fit and a cylindrical girdle of the female protrusion prevents the increase in the diameter of the cylindrical girdle on the male protrusion of the disk, in the proposed connection the increase in mechanical stress is excluded for this reason.

In addition, the stress level in the protrusions of the disks is significantly reduced due to the fact that grooves are made in them to accommodate the fixing elements instead of holes, as provided in the prototype, while only on the enclosing protrusion, which has a larger mass and experiences generally smaller deformations . Holes are known to be centers of concentration of significant mechanical stresses: especially intense deformation and cracking in joints is observed at the very edge of the protrusion behind the holes.

The installation of spikes in the recesses of the enclosing protrusion, through one, in conjunction with the execution on the walls of the recesses from the axis of the disks, oriented in the circumferential direction of the grooves, the exit of which, in the direction of the axis of the disks, is closed by the covered protrusion, as well as using fixing elements rods with a head and placing them in grooves with the possibility of locking the spike head in the recess provides a releasable connection and reliable fastening of disks to each other, which is extremely important for fixing the cover lawsuit on the rim of the main. The bend of the end of the rod protruding from the groove into the recess, free from the spike, protects the rod from falling out and increases the reliability of fastening in the connection.

The invention is illustrated by drawings, on which:

Figure 1. Part of the rotor of a gas turbine with the proposed disk connection, longitudinal section;

Figure 2. Fragment B in figure 1, on an enlarged scale;

Figure 3. Section AA in figure 1, without locking elements;

Figure 4. View In figure 2;

Figure 5. Disassembled disks of a gas turbine rotor, isometric view.

The drawings show the connection of the main disk with the cover rim. The connection includes a female protrusion 1 of the main disk, a male protrusion 2 of the cover disk and the fixing elements in the form of rods 3 with a head. The rods 3 in the illustrated example have a rectangular cross section. At the end of the free edge of the surrounding protrusion 1, recesses 4 are made, separated from each other by the walls 5. On the surface of the walls 5, grooves 6 for the rods 3 are formed in the circumferential direction in the circumferential direction. The male protrusion 2 is located inside the female protrusion 1 so that between a gap 7 is formed by their landing cylindrical belts. The male protrusion 2 is provided with radial spikes 8 installed in the recesses 4 of the female protrusion, through one.

The grooves 6 of the female protrusion 1 are closed on the side of the axis of the disks by the male protrusion 2. Each of the rods 3 is placed in the groove 6 with the possibility of locking the protrusion head in the recess 4. The end of the rod 3, protruding from the groove 6 into the recess 4 free from the spike, is bent. 4 have the form of two types: under the spike - rectangular, under the free ends of the rods 3 - a more rounded shape.

The assembly of the connection is as follows.

The cover disk is installed on the main disk by introducing the spikes 8 of the male protrusion 2 of the cover disk into the rectangular recesses 4 of the female protrusion 1 of the main disk. In this case, the cover disk is mounted on the main disk until the shoulder collar (not indicated in the drawing) of the male protrusion 2 at the ends of the walls 5. The placement of the spikes 8 in the rectangular recesses 4 provides a concentric position of the covering disk relative to the main one. Then the rods 3 are threaded from the side of the rectangular recesses 4 into the grooves 6, until the head rests against the wall 5, and the ends of the rods protruding from the groove into the round-shaped recess 4 of the spike 8 are bent using an unstressed method. Each of the spikes 8, thus, is pressed in by the heads of the two rods 3. After assembly, the movement of the cover disk relative to the main one in the circumferential, axial and radial directions is excluded.

Disassembling the connection of the disks includes bending the bent ends of the rods 3, removing the rods from the grooves 6 and disconnecting the annular protrusions of the disks.

Under conditions of gas turbine operation in small modes, the gap 7 between the landing cylindrical belts covering 1 and covered 2 protrusions on the rotor discs is maintained. When switching to high operating conditions, when the exhaust and heating of the cover disc in comparison with the main one proceeds faster, the gap 7 provides an unhindered increase in the diameter of the cylindrical girdle on the covered protrusion of the cover disc, while the metal of the protrusions does not experience additional mechanical stresses that usually arise due to interference by landing. As the diameter of the cylindrical girdle grows on the covered protrusion, the gap 7 is completely selected until a small calculated interference is formed. The absence of a gap at high conditions guarantees the tightness of the cavity formed between the main and cover disks, through which air is supplied to cool the blades. In the future, after the gas turbine goes back to small modes, due to faster cooling of the cover disk, there is a more rapid decrease in the diameter of the cylindrical girdle on the male protrusion of the cover disk compared to a decrease in the diameter of the girdle on the female protrusion of the main disk. As a result, a gap 7 is formed again. Thus, during the entire process of operation of the turbine, the total stress level in the material of the connected protrusions of the disks is much lower than in the case of using an integral connection selected as a prototype, where the fit is made with constant interference.

A gas turbine with a new rotor disk connection has passed lengthy bench tests as part of a gas turbine engine. When examining the disks after disassembling the rotor, no cracks were found on the protrusions of the disks, which confirms the high strength reliability of the disks at their joints.

Claims (1)

The connection of the disks of the rotor of a gas turbine, including the connected annular protrusions of the disks, one of which is female, the other male, and fixing elements, characterized in that the female protrusion is located on the main disk, male - on the cover, the locking elements are made in the form of rods with a head, with this covering protrusion from the end of the free edge is equipped with recesses, separated from each other by walls, on the surface of which grooves for the rods are formed in the circumferential direction from the axis of the disks, and the projected protrusion is placed with a radial clearance inside the female protrusion and provided with radial spikes installed in the recesses of the female protrusion, through one, and the grooves of the female protrusion are closed on the side of the axis of the disks by the male protrusion, and each of the rods in its corresponding groove is mounted with the possibility to lock it with the stud head in the recess, and the end of the rod protruding from the groove into the cleft-free recess, is bent.

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