JP2007182846A - Turbine rotor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily suppress unevenness in an axial position of a turbine of each turbine moving blade constituting a cascade. <P>SOLUTION: In this turbine rotor 100 provided with a turbine disc 50 having a plurality of disc channels 51 provided at an interval in the direction of rotation of turbine in an outer peripheral part and a plurality of turbine moving blades 1 having blade root parts 4 which are inserted into the disc channels 51 from the axial direction of the turbine and whose projecting parts 6 are engaged with recessed parts 52 of the disc channels 51, the projecting parts 6 of the blade root parts 4 and the recessed parts 52 of the disc channels 51 which are mutually engaged are formed into a circular arc shape projecting on an outer side in the radial direction of the turbine when viewed from the direction of rotation of the turbine. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a turbine rotor that is assembled by inserting turbine blades from a turbine axial direction into a disk groove of a turbine disk.

  The turbine rotor is usually configured by engaging a convex portion of a blade root portion of a turbine rotor blade with a concave portion of a disk groove of the turbine disk and fixing a plurality of turbine rotor blades around the turbine disk. In this type of turbine rotor, a turbine rotor blade is inserted into the disk groove of the turbine disk from the turbine axial direction and assembled. In this case, the concave part of the disk groove and the convex part of the blade root part are seen from the turbine rotational direction. Parallel to

  A pressure difference is generated between the fluid inlet side and the outlet side of the turbine rotor blade by a working fluid such as steam or combustion gas, and a force pressing in the flow direction acts on the turbine rotor blade. For this reason, it is usual to constrain the movement of the turbine blade in the working fluid flow direction by providing a groove having an angle with the insertion direction in the blade root and the disk groove of the turbine blade, and inserting a key or a pin into the groove. (See Patent Document 1 etc.).

JP 2004-257385 A

  As described above, in the conventional turbine rotor, the turbine rotor blade is usually fixed to the turbine disk with a key, a pin or the like, and the movement of the turbine rotor blade in the turbine axial direction is normally restricted. Therefore, at the turbine axial direction position between the turbine rotor blades adjacent to each other in the turbine rotation direction, a retaining groove on the blade root side of the turbine rotor blade, a retaining groove on the disk groove side, and a key (or pin) Variations occur due to the accumulated tolerance of manufacturing dimensions. For this reason, it is not easy to make the turbine row in which the turbine axial direction positions of the plurality of turbine rotor blades are close to the design values and to have a small variation in the turbine axial position of each turbine rotor blade.

  The present invention has been made in view of the above, and an object of the present invention is to provide a turbine rotor capable of easily suppressing variations in the turbine axial direction position of each turbine rotor blade constituting the cascade.

  (1) In order to achieve the above object, the present invention provides a turbine disk having a plurality of disk grooves provided at intervals in the turbine rotation direction at an outer peripheral portion, and is inserted from the turbine axial direction into the disk grooves. In a turbine rotor comprising a plurality of turbine rotor blades having blade root portions with which the convex portions engage with the concave portions of the disk grooves, the convex portions of the blade root portions and the concave portions of the disk grooves that are engaged with each other are in the turbine rotation direction. It is characterized by being formed in a circular arc shape protruding outward in the turbine radial direction.

  (2) In the above (1), preferably, the convex part of the blade root part is formed to have a larger curvature than the concave part of the disk groove.

  (3) In the above (1) or (2), more preferably, the convex portion and the concave portion are provided in a plurality of stages in the turbine radial direction, and the surface on the turbine radial direction outer side of each convex portion and each concave portion. The inner surface in the radial direction of the turbine is formed such that the vertex farthest from the turbine center line is located on a line orthogonal to the turbine center line when the turbine rotates.

  According to the present invention, the top of the arc surface of the convex portion of the blade root portion coincides with the top of the arc surface of the concave portion of the disk groove due to the centrifugal force at the time of turbine rotation, so that the turbine shaft of each turbine rotor blade constituting the blade row Variations in the direction position can be easily suppressed.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a partial perspective view showing a main part of a turbine rotor according to an embodiment of the present invention, and FIG. 2 is a front view showing the main part of the turbine rotor according to an embodiment of the present invention when viewed from the turbine axial direction. 3 is a cross-sectional view taken along the line II-II in FIG.
As shown in FIGS. 1 to 3, the turbine rotor 100 according to the present embodiment has a turbine disk 50 having a plurality of disk grooves 51 provided at intervals in the turbine rotation direction on the outer periphery, and the disk grooves 51. And a plurality of turbine rotor blades 1 having blade root portions 4 inserted from the turbine axial direction. Usually, the turbine rotor is configured by providing a plurality of such configurations in the turbine axial direction.

  The turbine blade 1 includes a blade profile portion 2, a root portion 3 of the blade profile portion 2, and the blade root portion 4. Further, in the present embodiment, an integral cover 5 formed integrally with the tip of the blade profile portion 2 is further provided. Each turbine rotor blade 1 is sequentially assembled into a so-called inverted Christmas tree type disk groove 51 of the turbine disk 50 from the turbine axial direction side, and a plurality of turbine rotor blades 1 are attached to the turbine disk 50 in the turbine rotation direction to constitute an annular blade row.

  The blade root portion 4 formed in a shape corresponding to the disk groove 51 includes a plurality of convex portions 6 extending in the turbine axial direction on the side surface facing the turbine rotation direction. A centrifugal force acting on the turbine rotor blade 1 during turbine rotation by engaging the surface on the turbine radial direction outer peripheral side of each convex portion 6 with the surface on the turbine radial direction inner peripheral side of the corresponding concave portion 52 of the disk groove 51. Power is supported.

  In the present embodiment, a case in which a so-called inverted Christmas tree type projecting portion 6 having a plurality of stages is used as the blade root portion 4 is illustrated. However, the blade root portion 4 is inserted into the turbine disk 50 from the turbine axial direction and incorporated. If there is, the shape and the like of the blade root portion are not particularly limited, and for example, the blade root portion may have only one step. The turbine rotor blade 1 is inserted into the turbine disk 50 from the turbine axial direction. However, the insertion direction does not necessarily need to be parallel to the turbine central axis when viewed from the outside in the turbine radial direction. This includes the case where the turbine is inclined by a set angle with respect to the turbine central axis when viewed from the outside in the radial direction.

  The most significant feature of the turbine rotor 100 configured as described above is that the convex portion 6 of the blade root portion 4 and the concave portion 52 of the disk groove 51 that are engaged with each other are outward in the turbine radial direction when viewed from the turbine rotation direction (circumferential direction). It is the point formed in the convex circular arc shape. In the present embodiment, the turbine radial direction outer surface of each convex portion 6 and the turbine radial direction inner surface of each concave portion 52 are such that the apex portion 7 farthest from the turbine center line is orthogonal to the turbine center line during turbine rotation. Is formed on a curved surface having the same curvature located on the line R (line along the turbine radial direction) R. However, as for the point where the apex portion 7 is located on the line R and the point having the same curvature, naturally, errors due to manufacturing tolerances, processing tolerances, etc. are allowed and not intended to be completely coincident. Further, the width dimension in the turbine radial direction of the recess 52 needs to ensure at least a gap that allows insertion of the blade root 4 into the disk groove 51 with respect to the width dimension in the turbine radial direction of the projection 6. .

  Here, in general, in each turbine blade constituting the same blade row, it is desirable that the turbine axial direction positions of the leading edge portion (working fluid inlet side blade end portion) are aligned as much as possible. Whether it is a steam turbine or a gas turbine, it is highly possible that the working fluid contains scales generated from piping, etc., dust generated after combustion of fuel, water droplets generated by thermodynamic changes, etc. When the turbine axial direction position of the leading edge portion of the moving blade is not uniform, the blade positioned upstream in the flow direction of the working fluid is eroded in advance.

  In the case of a turbine rotor blade that connects two adjacent ones in the rotational direction by connecting members such as so-called integral covers and tie bosses, the contact between the connecting members depends on the geometric positional relationship of the connecting members between adjacent blades. Since the connecting force is generated in the portion, if there is variation in the position of the turbine rotor blade in the axial direction of the turbine, deviation occurs in the connecting force that acts between the connecting members in the cascade.

  However, in the turbine rotor in which the turbine rotor blades are inserted into the turbine disk from the turbine axial direction as in the present embodiment, conventionally, the concave portion of the disk groove and the convex portion of the blade root portion are seen from the turbine rotational direction. And was formed in parallel. In this case, in order to constrain the pressing force of the working fluid such as steam or combustion gas in the direction of the working fluid flow on the turbine blade, the blade root and the disk groove of the turbine blade are fixed with a key or a pin. It was normal. Therefore, at the turbine axial direction position between the turbine rotor blades adjacent to each other in the turbine rotation direction, a retaining groove on the blade root side of the turbine rotor blade, a retaining groove on the disk groove side, and a key (or pin) Variations due to accumulated tolerances of manufacturing dimensions occur. For this reason, it is not easy to make the turbine row in which the turbine axial direction positions of the plurality of turbine rotor blades are close to the design values and to have a small variation in the turbine axial position of each turbine rotor blade.

  On the other hand, in the present embodiment, the convex portion 6 of the blade root portion 4 and the concave portion 52 of the disk groove 51 that are engaged with each other are processed into an arc shape convex outward in the turbine radial direction when viewed from the turbine rotation direction. Even if there is a slight variation in the axial position of each turbine rotor blade 1 when the turbine is stationary, the convex portion 6 of the blade root portion 4 and the apex portion 7 of the arc of the concave portion 52 of the disk groove 51 are line R when the turbine rotates. Each turbine rotor blade 1 is moved by the action of centrifugal force to a position that coincides with. In other words, the turbine rotor blade 1 of the present embodiment has an automatic alignment function that is positioned at a predetermined axial position during operation using the action of centrifugal force, thereby forming a blade row. It is possible to easily suppress variations in the turbine axial direction position of each turbine blade.

  Further, since the axial position of the rotating turbine blade is mainly due to the manufacturing tolerance of the arc portion of the convex portion 6 of the blade root 4 and the concave portion 52 of the disk groove 51, the turbine axial position of the turbine blade is constrained. Compared with the case where a key or a pin is used, an increase in positioning accuracy can be expected because there is no accumulation of manufacturing tolerances. Of course, compared to the conventional structure in which the turbine blades are prevented from coming out of the disk groove using a key or a pin, the disk groove and the groove for preventing the blade root part from being removed, and a turbine such as a key or a pin inserted into the groove. It is also a great merit that the structure for preventing the blade from coming off is unnecessary and the number of parts is reduced.

  Therefore, according to the present embodiment, the erosion of the leading edge of each turbine blade in the cascade and the connection force with the adjacent blades are less likely to vary, greatly contributing to the longer life and improved performance of the turbine rotor. Can do.

  Further, in the present embodiment, the concave portion 52 of the disk groove 51 and the convex portion 6 of the blade root portion 4 are provided in a plurality of stages in the turbine radial direction, and the convex portion 6 and the concave portion 52 each have a plurality of apex portions 7. Therefore, the disk groove 51 and the blade root part 4 have at least two contact points on each side in the turbine radial direction. Therefore, even if the turbine rotor blade 1 receives a force from the working fluid, the turbine blade 1 does not receive the force and fall down on the downstream side.

FIG. 4 is a cross-sectional view showing a main part of a turbine rotor according to another embodiment of the present invention, and is a cross-sectional view corresponding to FIG.
In the above-described embodiment, the inner surface in the turbine radial direction of the disk groove 51 and the outer surface in the turbine radial direction of the convex portion 6 of the blade root portion 4 are formed into curved surfaces having the same curvature. In the embodiment, the curved surface on the turbine radial direction outer side of the convex portion 6 of the blade root portion 4 is formed to have a larger curvature (that is, the radius of curvature is smaller) than the curved surface on the turbine radial direction inner side of the concave portion 52 of the disk groove 51 of the turbine disk 50. ing. Regarding other configurations, the present embodiment is the same as the embodiment described with reference to FIGS.

  In the present embodiment, in addition to the same effects as those of the above-described embodiments, the curvature of the curved surface on the blade root portion 4 side of the turbine rotor blade 1 is made larger than that on the disk groove 51 side, whereby each apex portion on the blade root portion 4 side. 7 is more likely to coincide with the line R, and there is an advantage that the self-aligning function can be more effectively operated.

  Note that the turbine rotor of the present invention described above can be applied to both a steam turbine and a gas turbine as described above. Further, the present invention can be applied to a high pressure stage or a low pressure stage. In addition, as described above, by applying the present invention to the turbine rotor that obtains the connecting force of the turbine rotor blade by the connecting member, the connecting force of the connecting member can be made uniform in the blade row. Turbine rotation by so-called pre-twist type turbine rotor blade that twists the blade profile part of the turbine blade that constitutes it in advance and attaches it to the turbine disk to apply the connection force to the connection member, and torsional deformation (untwist) during turbine rotation The present invention can be applied to any so-called untwisted type turbine blade that sometimes applies a coupling force to the coupling member, and a desired effect can be obtained.

It is a fragmentary perspective view showing the principal part of the turbine rotor which concerns on one embodiment of this invention. It is a front view showing the principal part of the turbine rotor which concerns on one embodiment of this invention seeing from a turbine axial direction. It is sectional drawing by the II-II cross section in FIG. It is sectional drawing showing the principal part of the turbine rotor which concerns on other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Turbine blade 4 Blade root part 6 Protrusion part 7 Apex part 50 Turbine disk 51 Disc groove 52 Concave part 100 Turbine rotor R Line orthogonal to turbine center line

Claims (3)

A turbine disk having a plurality of disk grooves provided at intervals in the turbine rotation direction, and a blade root part that is inserted from the turbine axial direction into the disk groove and engages with the convex part of the disk groove. A turbine rotor comprising a plurality of turbine rotor blades,
A turbine rotor characterized in that the projecting portion of the blade root portion and the recessed portion of the disk groove that are engaged with each other are formed in a convex arc shape outward in the turbine radial direction when viewed from the turbine rotation direction.   The turbine rotor according to claim 1, wherein the convex portion of the blade root portion is formed to have a larger curvature than the concave portion of the disk groove.   The turbine rotor according to claim 1 or 2, wherein the convex portion and the concave portion are provided in a plurality of stages in the turbine radial direction, and a surface on the turbine radial direction outer side of each convex portion and a surface on the turbine radial direction inner side of each concave portion are The turbine rotor is formed so that the vertex farthest from the turbine center line is positioned on a line orthogonal to the turbine center line when the turbine rotates.

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