JP2007187053A - Turbine blade - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a turbine blade having improved assembling efficiency while securing the contact area of tie bosses. <P>SOLUTION: The turbine blade is inserted into a disc groove 9 of a turbine disc 8 in the direction of a rotor shaft, where the tie bosses 5, 6 contact each other with the re-twist of a blade profile portion 2 during the rotation of a rotor to connect adjacent blades to each other. A cutout portion 28 is provided on the steam outlet side of a contact face 23 with the tie boss 6 on the adjacent blade belly side of the tie boss 5 on the back side. A cutout portion 25 is provided on the steam inlet side of a contact face 22 with the tie boss 5 on the adjacent blade back side of the tie boss 6 on the belly side. The cutout portions 25, 28 are formed so that a gap is formed between the tie bosses 5, 6 of the opposed adjacent blades in view from an inserting direction I of a blade implanted portion 7 when the adjacent blades are turned down in the direction of isolating each other in a range of rattling between the blade implanted portion 7 and the disc groove 9. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a turbine rotor blade of a steam turbine, and more particularly to a turbine rotor blade that is incorporated into a turbine disk from the axial direction of the rotor and uses a twisting return of a blade profile portion at the time of rotor rotation as a connecting force between adjacent blades.

  For long blades such as the last stage rotor blade of a steam turbine, an integral cover (or integral shroud) provided at the tip of the blade or an intermediate connecting member provided at the intermediate portion of the blade (generally “integral snubber” or “tie boss”) (Hereinafter referred to as “tie boss” in the present specification), etc., which are brought into contact with each other by untwisting deformation (untwisting) by a centrifugal force during rotation, thereby connecting adjacent blades during rotor rotation. Yes (see Patent Document 1).

JP-A-4-5402

  A blade profile portion of a moving blade of a steam turbine used in a thermal power plant or a nuclear power plant is twisted from the blade root to the blade tip. When the rotor rotates, centrifugal force acts on the blade profile portion, and thus the twisting deformation (untwist) occurs in the blade profile portion due to the centrifugal force. In addition, since the blade cross-sectional area increases from the blade tip toward the blade root, the torsional rigidity of the blade cross-section increases as the blade material is closer to the blade root. The contact force between the tie bosses is much greater than the contact force between the integral covers provided at the blade tips. For this reason, the connecting member provided in the blade intermediate portion needs to have high strength and a wide contact surface.

  On the other hand, in order to avoid interference of tie bosses between adjacent blades when the turbine blades are incorporated into the turbine disk from the rotor axial direction, the direction in which the adjacent turbine blades are separated from each other using the gap of the disk groove. The turbine blades are inserted into the turbine disk in a state where it is tilted down. In this case, the width dimension of the contact surface between the tie bosses of adjacent blades can only be taken up to twice the distance that the tie boss moves when the turbine blade is pushed down by utilizing the gap of the disk groove. In order to incorporate the turbine blades one by one into the turbine disk, it is difficult to increase the contact area of the tie bosses. To avoid this, an assembly method in which all the turbine blades are assembled in an annular shape in advance (or slightly inserted into the turbine disk) and then pushed into the turbine disk at the same time may be adopted. Jigs for use are required.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a turbine rotor blade capable of achieving both improvement in assemblability and securing of a contact area of a tie boss.

  (1) To achieve the above object, according to the present invention, there is provided a blade implantation portion that is inserted from a rotor axial direction into a plurality of disk grooves provided at intervals in the blade rotation direction on the turbine disk outer peripheral portion and engaged with the blade implantation portion. A blade profile portion twisted from the blade root portion fixed to the blade portion to the blade tip portion, and a pair of intermediate connecting members provided on the back side and the abdomen side of the blade profile in a predetermined position in the blade length direction. In the turbine rotor blade that connects the adjacent blades by contacting the intermediate connecting member by twisting back the blade profile during rotation, the intermediate connecting member on the back side is a contact surface with the intermediate connecting member on the adjacent blade side. On the steam outlet side, there is a notch formed so as to be along the surface along the insertion direction of the blade implanting portion when the rotor is stationary or to be retracted to the blade profile portion side from the surface. On the other hand, the middle connecting member on the abdomen side is on the steam inlet side of the contact surface with the intermediate connecting member on the back side of the adjacent blade, along the surface along the insertion direction of the blade implanting portion when the rotor is stationary. It has a cutout portion formed so as to retreat to the wing profile portion side from the surface, and the dorsal and ventral cutout portions are within a range of play between the wing implantation portion and the disk groove. When the adjacent wings are tilted away from each other, the gap is provided so that a gap is generated between the dorsal and ventral intermediate connecting members of the adjacent wings when viewed from the insertion direction of the wing implantation portion. It is characterized by being.

  (2) In order to achieve the above-mentioned object, the present invention also includes a blade-planting portion that is inserted and engaged from a rotor axial direction in a disk groove provided in the turbine disk outer peripheral portion at intervals in the blade rotation direction, and the blade A blade profile portion twisted from the blade root portion to the blade tip portion fixed to the implantation portion, an integral cover provided at the tip portion of the blade profile portion, and a back side and a stomach of a predetermined position in the blade length direction of the blade profile portion. A turbine rotor blade having a pair of intermediate connecting members provided on each side and connecting the adjacent blades by bringing the intermediate connecting member and the integral cover into contact with each other by twisting back of the blade profile during rotation. The intermediate connecting member on the side is in the steam outlet side of the contact surface with the intermediate connecting member on the side adjacent to the blade, along the insertion direction of the blade implanting portion in a state where the rotor is stationary The ventral intermediate coupling member is a steam inlet on the contact surface with the intermediate coupling member on the back side of the adjacent blade. A notch portion formed so as to be along the surface along the insertion direction of the wing implantation portion or to be retracted to the wing profile portion side from the surface when the rotor is stationary. When the side blades and the ventral side cut-out portions are tilted in a direction in which the adjacent blades are separated from each other within the range of the wing implantation portion and the disk groove, the adjacent blades facing each other when viewed from the insertion direction of the blade implantation portion. It is provided so that a gap may be formed between the intermediate connecting members on the dorsal side and the ventral side.

  (3) In order to achieve the above object, the present invention also includes a blade implanting portion that is inserted from a rotor axial direction into a plurality of disk grooves provided at intervals in the blade rotation direction on the outer peripheral portion of the turbine disk, and engages with the blade. A wing profile portion twisted from the wing root portion fixed to the implantation portion to the wing tip portion, and a pair of intermediate connecting members provided on the back side and the abdomen side of the wing profile direction predetermined position of the wing profile portion, In the turbine rotor blade in which the intermediate connecting member is brought into contact with each other by connecting the blades by twisting back of the blade profile during rotation, the intermediate connecting member on the back side is steam on the contact surface with the intermediate connecting member on the adjacent side of the adjacent blade. On the outlet side, the ventral intermediate connecting member has a notch on the steam inlet side of the contact surface with the intermediate connecting member on the adjacent blade back side. Wherein the absolute value of the angle formed between the surface along the insertion direction of the blade implanted section is formed so as to be 5 ° or less in the state when the rotor stationary.

  (4) In order to achieve the above object, the present invention also provides a blade-planting portion that is inserted from a rotor axial direction into a plurality of disk grooves provided at intervals in the blade rotation direction on the turbine disk outer peripheral portion and engaged with the blade-growing portion. A blade profile portion twisted from the blade root portion to the blade tip portion fixed to the implantation portion; an integral cover provided at the tip portion of the blade profile portion; A turbine rotor blade having a pair of intermediate connecting members provided on each side and connecting the adjacent blades by bringing the intermediate connecting member and the integral cover into contact with each other by twisting back of the blade profile during rotation. The intermediate connecting member on the side is on the steam outlet side of the contact surface with the intermediate connecting member on the adjacent blade, and the intermediate connecting member on the vent is in contact with the intermediate connecting member on the back side of the adjacent blade. The steam inlet side of each has a notch, and the notch has an absolute value of the angle between the wall surface and the surface along the insertion direction of the wing implantation part when the rotor is stationary. It is formed so that it may become 5 degrees or less.

  According to the present invention, it is possible to ensure the maximum contact area of the tie bosses between adjacent blades provided in the blade intermediate portion while ensuring assemblability.

  Steam turbine rotor blades used in fire power plants, nuclear power plants, and the like are twisted from the blade root to the blade tip. Centrifugal force acts from the blade root toward the blade tip on the blade profile portion of the turbine blade fixed on the circumference of the turbine disk as the rotor of the steam turbine rotates. Since the blade profile portion is twisted, the blade profile portion is twisted back (untwisted) due to centrifugal force. In addition, since the blade cross-sectional area increases from the blade tip toward the blade root, the torsional rigidity with respect to the blade cross-section increases with the same material from the blade tip toward the blade root.

  Also, in general, the moving blades of a steam turbine are constantly excited over a wide frequency range by the flow of working fluid (steam) and its turbulence components. The vibration response of the wing structure to these excitation forces is related to the natural frequency and the magnitude of the damping force in each vibration mode.

  Therefore, a connecting member called an integral cover (or integral shroud) is provided at the blade tip, and the adjacent blade tips are connected using an untwist generated by the centrifugal force acting on the rotor blade when the turbine rotates. Connect the members. By constraining the tip of the turbine rotor blade in this way, it is possible to expect an additional effect of increasing the rigidity of the blade structure and vibration damping during the rotation of the turbine (rotor). Thereby, it is possible to suppress the resonance in the low-order vibration mode having a large resonance response and to improve the reliability with respect to the resonance in the high-order vibration mode having a small resonance response.

  However, when the blade length becomes longer than 32 inches, for example, as in the last stage moving blade of the steam turbine low-pressure stage, the vibration amplitude increases and local excessive stress is applied to the vicinity of the integral cover at the tip of the blade or the root of the blade. May occur and damage may occur at these locations. Therefore, an intermediate connecting member (generally referred to as “integral snubber” or “tie boss” at each of the ventral side and the back side at a predetermined position between the blade root part and the blade tip part. In the same way, tie bosses are connected between adjacent blades using untwisting at the time of rotor rotation, and stress concentration is reduced by constraining the blade middle part in addition to the blade tip. It is conceivable to suppress the generation of excessive stress.

  In such turbine blades, the torsional moment required to apply a torsional moment between the blade root and the blade tip (hereinafter referred to as “blade intermediate part”) and twist the blade intermediate part cross section by a certain angle is Compared to the torsional moment required to twist the blade tip section by the same angle by applying a torsional moment to the tip. In other words, when the untwist angle generated with the rotation of the rotor is constrained to a constant angle by the integral cover provided near the blade tip or the tie boss provided in the middle of the blade, the untwist at the blade tip is restrained. Therefore, the moment necessary for restraining the untwisting of the blade intermediate portion is very large compared to the moment necessary for this. The moment necessary for restraining the untwist can be expressed by the product of the reaction force acting on the contact surface of the connecting member and the length of the arm between the points of action of the reaction force. Therefore, the reaction force acting on the contact surface of the tie boss in the middle portion of the blade is much larger than the reaction force acting on the contact surface of the connecting member at the blade tip portion. Therefore, tie bosses are required to have a wide contact area and high strength.

  On the other hand, when assembling a turbine blade inserted into the disk groove of the turbine disk from the rotor axis direction (usually with an inclination of about 0 ° to 20 ° with respect to the central axis of the rotor), the vicinity of the tie boss is compared to the blade tip. The blades are less elastically deformed and the amount of movement when the blades are tilted using the gap in the disk groove is small. Therefore, to avoid interference between the tie bosses between adjacent blades, it is necessary to reduce the circumferential width of the tie bosses. There is a requirement contrary to ensuring a wide contact area and high strength as described above. In the embodiment of the present invention to be described next, it is possible to achieve both avoidance of tie boss interference during assembly and securing of a large contact area and high strength of the tie boss.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a perspective view of a turbine rotor blade according to an embodiment of the present invention, FIG. 2 is a view of the turbine rotor blade according to an embodiment of the present invention as viewed from the outside in the rotor radial direction, and FIG. It is a perspective view showing the state where the turbine rotor blade concerning one embodiment was integrated in the turbine disk.
As shown in FIGS. 1 to 3, the turbine rotor blade (blade) 1 according to the present embodiment is inserted into and engaged with a plurality of disk grooves 9 provided at intervals in the blade rotation direction on the outer peripheral portion of the turbine disk 8. Wing implantation part 7, blade profile part 2 twisted from blade root part 2a fixed to blade implantation part 7 to blade tip part 2b, integral covers 3 and 4 provided on tip part 2b of blade profile part 2, and blade profile It has a pair of tie bosses 5 and 6 provided on the back side and the abdomen side of the portion 2 at a predetermined position in the blade length direction. This turbine rotor blade 1 is applied to a long blade having a relatively long blade length in a stage near the final stage of the steam turbine, and the length from the blade root portion 2a of the blade profile portion 2 to the blade tip portion 2b is, for example, 48 inches. Degree.

  In the present embodiment, a case where a so-called “reverse Christmas tree type” is used as the wing implantation part 7 is illustrated. However, if the wing implantation part is inserted and incorporated into the turbine disk from the rotor axial direction, the wing implantation part is illustrated. The shape and the like are not particularly limited. The turbine rotor blade 1 is inserted into the turbine disk 8 from the rotor axial direction. However, the insertion direction I does not necessarily follow the rotor central axis C, and as shown in FIG. This includes the case where the set angle α (for example, about 0 ° to 20 °) is inclined with respect to the rotor central axis C when viewed from the outside in the radial direction.

  The integral cover 3 extends on the back side of the blade and the integral cover 4 extends on the side of the blade. The tie boss 5 is on the blade back side of the blade profile portion 2 at a predetermined position in the blade length direction (between the blade root portion 2a and the blade tip portion 2b, hereinafter referred to as “wing intermediate portion”). Each protrudes to the side. The integral covers 3 and 4 and the tie bosses 5 and 6 are all formed integrally with the blade profile portion 2. Further, the tie bosses 5 and 6 are often provided at substantially the central part (1/2 of the blade length) of the blade profile part 2 in the blade length direction, but depending on the torsional rigidity and the like of the blade profile part 2 It may be provided with a staggered position. The tie bosses 5 and 6 may also be provided at a substantially central portion between the leading edge (steam inlet side edge) and the trailing edge (steam outlet side edge) of the blade profile portion 2 on a line along the rotor central axis C. Many.

  When the turbine rotor blade 1 of the present embodiment is incorporated into the turbine disk 8, the blade implantation portion 7 is inserted and fitted into the disk groove 9 of the turbine disk 8 from the rotor axial direction. In this way, the turbine rotor blades 1 are incorporated at intervals in the circumferential direction (rotation direction) of the turbine disk 8, and an annular blade row is formed by several tens of turbine rotor blades 1 implanted in the outer peripheral portion of the turbine disk 8. Is done. In FIG. 3, a part of the turbine disk 8 is extracted and illustrated, but actually, the turbine disk 8 is formed in an annular shape.

  In the turbine rotor configured as described above, centrifugal force acts on the blade profile portion 2 from the blade root 2a toward the blade tip 2b as the rotor rotates. Since the blade profile portion 2 is twisted, untwisting occurs in the blade profile portion 2 due to centrifugal force. In FIG. 3, the direction of the untwist moment acting on the blade tip of the central turbine blade 1 is indicated by an arrow 11, and the blade tip of the turbine blade 1 'adjacent to the ventral side of the turbine blade 1 with respect to the rotor rotation direction. The direction of the untwist moment acting on the part is indicated by an arrow 12. Similarly, the directions of untwisting moments acting on the blade intermediate portions of the turbine rotor blades 1, 1 ′ are indicated by arrows 13 and 14. Further, when the adjacent blades are connected by bringing the integral covers 3 and 4 and the tie bosses 5 and 6 into contact with each other by an untwist acting on the blade tips and middle portions of the turbine rotor blades 1 and 1 ′ when the rotor rotates. As a reaction of the twist moment, a torsional moment opposite to the untwist moment acts on the wing implantation portion 7. The direction of this torsional moment is indicated by arrows 15 and 16, respectively.

4 is a perspective view of blade tips of adjacent turbine blades according to an embodiment of the present invention, and FIG. 5 is a plan view of the blade tips of the turbine blade in FIG. 4 viewed from the outside in the rotor radial direction. It is.
As shown in FIGS. 4 and 5, of the integral cover 4 of the turbine blade 1, the contact surface 17, which is the end surface facing the integral cover 3 of the turbine blade 1 ′, is the turbine blade 1 when the rotor is stationary. A gap 19 is provided between the integral cover 3 and the contact surface 18 that is the end face of the turbine rotor blade 1 facing the integral cover 4. These contact surfaces 17 and 18 are substantially parallel and are inclined at a predetermined angle with respect to the line 20 along the rotor rotation direction.

  From the viewpoint of improving the rigidity of the blade tip, the gap 19 is close to 0, and the contact surfaces 17 and 18 are preferably in point contact when the rotor is stationary. Alternatively, the gap 19 may be provided to such an extent that the contact surfaces 17 and 18 start to come into contact with each other at a low rotor speed immediately after the start of rotation of the rotor (for example, about several millimeters). In this way, the contact surfaces 17 and 18 of the integral cover of the turbine blades 1 and 1 ′ are brought into contact with each other by the untwist moments 11 and 12 acting on the turbine blades 1 and 1 ′ as the rotor speed increases. The untwist at the tip of the wing is restrained (see FIG. 6). In other words, at the blade tip, at the same time as the rotor starts to rotate (or during the extremely low rotation of the rotor (several tens to several hundred rpm)), the integral cover between the turbine rotor blades adjacent to each other in the rotor rotation direction is provided. The contact is made by all the turbine blades constituting the blade row, so that the turbine blades of the blade row are connected in an annular shape.

FIG. 7 is a perspective view showing the blade intermediate portions of adjacent turbine blades cut out according to an embodiment of the present invention, and FIGS. 8 and 9 show the blade intermediate portions of the turbine blades in FIG. It is the top view (sectional view) seen from the direction outer side.
As shown in FIGS. 7 to 9, of the tie bosses 6 of the turbine rotor blade 1, the contact surface 22 that is the end surface facing the tie boss 5 of the turbine rotor blade 1 ′ is a tie boss 5 of the turbine rotor blade 1 ′ when the rotor is stationary. Among these, a gap 24 is provided between the turbine rotor blade 1 and the contact surface 23 which is an end surface facing the tie boss 6. As with the integral cover, the contact surfaces 22 and 23 of the tie bosses of the turbine blades 1 and 1 ′ are brought into contact by the untwist moments 13 and 14 acting on the turbine blades 1 and 1 ′ as the rotor rotates and rises. The untwist of the wing middle part is restrained.

  Further, the tie boss 6 on the ventral side of the turbine rotor blade 1 has a notch 25 on the steam inlet side of the contact surface 22 with the tie boss 5 on the back side of the adjacent blade 1 ′. The notch 25 is formed so as to retreat to the blade profile portion 2 side of the turbine rotor blade 1 along the surface along the insertion direction I of the blade implantation portion 7 when the rotor is stationary. On the other hand, the tie boss 5 on the back side of the turbine rotor blade 1 ′ has a notch 28 on the steam outlet side of the contact surface 23 with the tie boss 6 on the abdomen side of the adjacent blade 1. The notch 28 is formed so as to retreat to the blade profile portion 2 side of the turbine rotor blade 1 ′ along the surface along the insertion direction I of the blade implantation portion 7 when the rotor is stationary. .

  At this time, the turbine rotor blades 1 and 1 '(of course, the other rotor blades are also the same as the insertion direction I up to the maximum angle γ within the range of the backlash of the blade implantation portion 7 and the disk groove 9 as shown in FIG. Can be tilted in the orthogonal direction. The notch portions 25 and 26 of the tie bosses 6 and 5 of the turbine rotor blades 1 and 1 ′ facing each other, when the turbine rotor blades 1 and 1 ′ are tilted away from each other within the range of the angle γ, 7 is provided such that a gap is formed between the tie bosses 5 and 6 when viewed from the insertion direction I of FIG.

  More specifically, the blade tip portion (integral cover portion) and the blade intermediate portion (tie boss portion) are adjacent to each other in the rotational direction by an untwist acting on the blade as the rotor rotates. Touch and connect. After contact, the untwist at the tip of the blade and the untwist at the middle of the blade are constrained, so that a reaction force acts on the contact surfaces 17, 18, 22 and 23, and this reaction force increases with the rotation of the rotor. Increase. The same applies to the surface pressure (reaction force per unit area) acting on the contact surface. As described above, since the surface pressure acting on the contact surfaces 22 and 23 of the blade intermediate portion (tie boss portion) is much higher than the surface pressure acting on the contact surfaces 17 and 18, the area of the contact surfaces 22 and 23 is reduced. It is important to secure rigidity.

  On the other hand, in assembling the turbine rotor blade 1 having the inverted Christmas tree type wing implantation part 7, the wings are implanted in order to prevent the tie bosses 5 and 6 of adjacent wings from interfering with each other when inserted into the disk groove 9. 7 and the disk groove 9 are used to assemble the adjacent blades with the back turbine blade 1 lying on the back and the abdominal turbine blade 1 'lying on the belly. When assembled by this method, the interference width 29 in the direction perpendicular to the blade insertion direction I of the tie bosses 5 and 6 in a state where both the turbine rotor blades 1 and 1 ′ are upright is in a direction in which the blades 1 and 1 ′ are separated from each other. The upper limit is twice the movement distance of the tie bosses 5 and 6 when the angle γ is defeated. That is, the maximum angle γ (usually less than 1 °) at which the wing implantation portion 7 can rotate within the disk groove 9 around the groove bottom 30 (see FIG. 10), and the height L (from the blade root portion 2a of the tie bosses 5 and 6). If the interference width 29 is not limited to 2 × L × sin γ or less, the assembly becomes difficult.

  However, when the above conditions are satisfied, it is difficult to secure a large contact area between the tie bosses 5 and 6 in order to assemble the blades one by one. If the assembly method is not limited as long as it is assembled in a ring shape before it is inserted into the rotor or slightly inserted into the rotor, and then pushed into the rotor at the same time, but in this case, for very large assembly This jig is required.

  Therefore, for example, the surface (notch portion) 28 on the steam outlet side of the surfaces 26 and 28 adjacent to the contact surface 23 of the tie boss 5 provided on the back side of the blade is the rotor center as viewed from the outer side in the rotor radial direction. Of the surfaces 25 and 27 adjacent to the contact surface 22 of the tie boss 6 provided on the ventral side and the angle formed with respect to the axis C, the surface (notch portion) 25 on the steam inlet side is viewed from the outside in the rotor radial direction. When the angle formed is β, the angle β is set so that the difference between the insertion direction I shown in FIG. 2 and the angle α formed with respect to the rotor central axis C is within ± 5 °. Thus, when | α−β | ≦ 5 °, if the length of the contact surfaces 22 and 23 of the tie bosses 5 and 6 is about 10 mm, then 10 mm × (± tan 5 °) = ± 0.9 mm, A value equivalent to a general design tolerance of the gap 24 is obtained. On the contrary, if the angle β is increased to α + 5 ° or more while the gap 29 and the angle α are constant, the rigidity of the tie bosses 5 and 6 is lowered. Further, if the angle β is reduced to α−5 ° or less while the angle α is constant, the contact surfaces 22 and 23 are reduced when the gap 29 is constant, and the gap 29 is determined when the contact surfaces 22 and 23 are constant. Will increase the size of the product and hinder assembly.

  That is, in a turbine rotor blade of a type in which adjacent blades are connected to each other by a connecting member using a built-in untwist with respect to the turbine disk from the rotor axial direction, | α−β | ≦ 5 ° under general design conditions Thus, as described above, when the turbine rotor blades 1 and 1 ′ are tilted away from each other within the range of the angle γ, as seen from the insertion direction I of the blade implantation portion 7, A gap is generated. Thereby, according to this Embodiment, the contact area of the tie boss | hub of the adjacent blade | wings provided in the blade intermediate part can be ensured to the maximum, ensuring assembly property.

  In the above description, the turbine blade provided with the integral cover 3 and 4 at the blade tip as a connecting member between adjacent blades in addition to the tie bosses 5 and 6 at the blade intermediate portion has been described as an example. The present invention can also be applied to a turbine rotor blade provided with only a tie boss at the intermediate portion of the blade without the integral cover of the portion, and the same effect can be obtained. The present invention can also be applied to a turbine rotor blade provided with only an integral cover at the blade tip, and the same effect can be obtained.

FIG. 11 is a mechanical block diagram of a steam turbine to which the turbine rotor blade of the present invention is applied.
The steam turbine shown in FIG. 11 is used in a thermal power plant. In FIG. 11, 26 is a rotor, 27 is a stationary blade (nozzle), 28 is an outer casing, and 29 is main steam. Several tens of turbine rotor blades 1 are provided on the same circumference of the rotor 26. A set of turbine rotor blades on the same circumference of the rotor 26 is referred to as a paragraph, and this paragraph is provided in a plurality of stages in the axial direction of the rotor 26.

  In the steam turbine configured in this way, the main steam 29 from the steam generator (not shown) passes through the stationary blade 27 provided in the outer casing 28 corresponding to the moving blade 1 and is provided in the rotor 26. Then, the rotor blades 1 are guided to the rotor blades 1, and thereby the rotational power is given to the rotor 26. This rotational power is transmitted to a generator provided at one end of the rotor 26, whereby the rotational energy of the rotor 26 is converted into electric energy to generate electric power. In the steam turbine, the blade length of the turbine rotor blade is longer toward the downstream stage of the steam. That is, the turbine blade 1 at the final stage closest to the condenser has the longest blade length, so that it is under the severest condition in terms of strength vibration. The blade length of the last stage of the low pressure steam turbine used in the thermal power plant is usually about 30 to 60 inches. Therefore, in such a steam turbine, for example, an integral cover and a tie boss are provided on the last stage turbine blade 1 and the last stage turbine blade 1, and a tie boss is provided on the other stage turbine blade 1. Only install an integral cover.

1 is a perspective view of a turbine rotor blade according to an embodiment of the present invention. It is the figure which looked at the turbine bucket which concerns on one embodiment of this invention from the rotor radial direction outer side. 1 is a perspective view showing a state in which a turbine rotor blade according to an embodiment of the present invention is incorporated in a turbine disk. 1 is a perspective view of blade tip portions of adjacent turbine blades according to an embodiment of the present invention. FIG. It is the top view which looked at the blade front-end | tip part of the turbine rotor blade in FIG. 4 from the rotor radial direction outer side. FIG. 6 is a plan view illustrating a state in which blade tip portions of the turbine rotor blade illustrated in FIG. 5 are coupled. It is the perspective view which cut and represented the blade | wing intermediate part of the turbine rotor blade which adjoins one embodiment of this invention. FIG. 8 is a plan view (cross-sectional view) of a blade intermediate portion of the turbine rotor blade in FIG. 7 viewed from the outside in the rotor radial direction. FIG. 8 is a plan view (cross-sectional view) of a blade intermediate portion of the turbine rotor blade in FIG. 7 viewed from the outside in the rotor radial direction. FIG. 3 is a schematic view of the vicinity of a turbine rotor blade root portion in a state in which the turbine rotor blade is tilted using a gap between a blade implantation portion and a disk groove. It is a machine block diagram of the steam turbine to which the turbine rotor blade of this invention is applied.

Explanation of symbols

1, 1 'Turbine blade 2 Blade profile part 2a Blade root part 2b Blade tip part 3, 4 Integral cover 5, 6 Tie boss 7 Blade implantation part 8 Turbine disk 9 Disc groove 22, 23 Contact surface 25, 28 Notch C Rotor center axis I Insertion direction α ～ γ Angle

Claims (4)

A blade planting portion that is inserted from a rotor axial direction into a plurality of disk grooves provided at intervals in the blade rotation direction on the outer periphery of the turbine disk and engaged, and a blade twisted from the blade root portion fixed to the blade implantation portion to the blade tip portion A profile portion and a pair of intermediate connection members provided on the back side and the abdomen side of the blade length direction predetermined position of the blade profile portion, and the intermediate connection member is rotated by twisting back of the blade profile portion when the rotor rotates. In turbine blades that contact and connect adjacent blades,
The intermediate connecting member on the back side is on the steam outlet side of the contact surface with the intermediate connecting member on the adjacent wing belly side, along the surface along the insertion direction of the wing implantation part in the state when the rotor is stationary, or from the surface thereof While also having a notch portion formed to retract to the wing profile portion side,
The middle connecting member on the abdomen side is on the steam inlet side of the contact surface with the intermediate connecting member on the back side of the adjacent wing, along the surface along the insertion direction of the wing implantation part in a state where the rotor is stationary, or from the surface thereof Also has a notch formed to retract to the wing profile part side,
The dorsal and ventral cutouts face each other when viewed from the insertion direction of the wing implantation part when the adjacent wings are tilted away from each other in the range of play of the wing implantation part and the disk groove. A turbine rotor blade characterized by being provided so that a gap is generated between the intermediate connecting members on the back side and the abdomen side of adjacent blades. A blade planting portion that is inserted from a rotor axial direction into a plurality of disk grooves provided at intervals in the blade rotation direction on the outer periphery of the turbine disk and engaged, and a blade twisted from the blade root portion fixed to the blade implantation portion to the blade tip portion A profile portion, an integral cover provided at the tip of the blade profile portion, and a pair of intermediate connecting members provided on the back side and the abdomen side of the blade profile in a predetermined position in the blade length direction. In the turbine blade that connects the adjacent blades by contacting the intermediate connecting member and the integral cover by twisting back of the blade profile portion at the time,
The intermediate connecting member on the back side is on the steam outlet side of the contact surface with the intermediate connecting member on the adjacent wing belly side, along the surface along the insertion direction of the wing implantation part in the state when the rotor is stationary, or from the surface thereof While also having a notch portion formed to retract to the wing profile portion side,
The middle connecting member on the abdomen side is on the steam inlet side of the contact surface with the intermediate connecting member on the back side of the adjacent wing, along the surface along the insertion direction of the wing implantation part in a state where the rotor is stationary, or from the surface thereof Also has a notch formed to retract to the wing profile part side,
The dorsal and ventral cutouts face each other when viewed from the insertion direction of the wing implantation part when the adjacent wings are tilted away from each other in the range of play of the wing implantation part and the disk groove. A turbine rotor blade characterized by being provided so that a gap is generated between the intermediate connecting members on the back side and the abdomen side of adjacent blades. A blade planting portion that is inserted from a rotor axial direction into a plurality of disk grooves provided at intervals in the blade rotation direction on the outer periphery of the turbine disk and engaged, and a blade twisted from the blade root portion fixed to the blade planting portion to the blade tip portion It has a profile part and a pair of intermediate connecting members provided on the back side and the abdominal side of the blade profile in a predetermined position in the blade length direction, and contacts the intermediate connecting member by twisting back of the blade profile part during rotation. In turbine blades that connect adjacent blades,
The intermediate connecting member on the back side is on the steam outlet side of the contact surface with the intermediate connecting member on the adjacent blade back side, and the intermediate connecting member on the back side is on the steam inlet side on the contact surface with the intermediate connecting member on the adjacent blade back side. Each has a notch,
These notches are formed so that the absolute value of the angle between the wall surface and the surface along the insertion direction of the wing implantation portion is 5 ° or less when the rotor is stationary. Turbine blades. A blade planting portion that is inserted from a rotor axial direction into a plurality of disk grooves provided at intervals in the blade rotation direction on the outer periphery of the turbine disk and engaged, and a blade twisted from the blade root portion fixed to the blade planting portion to the blade tip portion A profile portion, an integral cover provided at the tip of the blade profile portion, and a pair of intermediate connecting members provided on the back side and the abdomen side of the blade profile in a predetermined position in the blade length direction. In the turbine blade that connects the adjacent blades by contacting the intermediate connecting member and the integral cover by twisting back of the blade profile portion at the time,
The intermediate connecting member on the back side is on the steam outlet side of the contact surface with the intermediate connecting member on the adjacent blade back side, and the intermediate connecting member on the back side is on the steam inlet side on the contact surface with the intermediate connecting member on the adjacent blade back side. Each has a notch,
These notches are formed so that the absolute value of the angle between the wall surface and the surface along the insertion direction of the wing implantation portion is 5 ° or less when the rotor is stationary. Turbine blades.

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