JP2003270081A - Support structure of turbine moving blade - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the occurrence of cracks due to fatigue breakdown from a portion other than a blade section that is a rating section by strongly performing cantilever support and fixation of a turbine moving blade to a tool-chucking section that is mounted to a fatigue-testing machine. <P>SOLUTION: Projecting portions of loop-side and rear-side clamps (8a, 8b) are inserted and engaged into loop-side and rear-side shank pockets (4a, 4b) of a shank section (4) at one end of a blade section (2) of a turbine moving blade (10), and the bottom surface of the shank pockets is gripped for fixing from both sides in the rotary direction of a turbine. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for supporting a turbine rotor blade, and more specifically, it is mainly used for a high cycle by supporting and fixing the turbine rotor blade to a jig attached to a fatigue tester. TECHNICAL FIELD The present invention relates to a turbine rotor blade support structure for performing a fatigue test.

[0002]

2. Description of the Prior Art Forces and moments in various directions act on the turbine rotor blade of a gas turbine for converting the kinetic energy of a fluid into rotary motion to obtain rotary power. For confirmation, various strength tests are performed before the actual production. Fracture of moving metal parts is often due to fatigue of the material.Therefore, a fatigue test, in which a turbine blade that is a test piece is continuously and repeatedly vibrated, is the most important factor in ensuring the reliability of the turbine blade. This is one of the important strength tests.

First, the name of each part of the turbine rotor blade will be described with reference to the perspective view of the turbine rotor blade shown in FIG. This turbine rotor blade (10) has a blade portion (2) formed in a blade shape.
And a platform portion (7) formed at one end of the wing portion, and the platform portion includes a shank portion (4) and a tab tail portion (6). On both sides of the shank portion (4), there is formed a substantially elliptic cylinder-shaped recess formed in the rotational direction of the turbine rotor blade, that is, in the direction substantially normal to the blade surface (vertical direction in the figure). This recess is generally located on the ventral side of the wing surface and is located on the ventral side shank pocket (4
a) and the one on the back side is called the back side shank pocket (4b). The shank pockets (4a, 4b) on the ventral side and the dorsal side are required to reduce the weight of the turbine rotor blade (10), which is a moving portion, and have the minimum necessary thickness for securing the strength of the turbine rotor blade. This is the result of scraping off the material of the shank part while leaving the thickness.

The shank portion (4) integrally has a tab tail portion (6) for locking and fixing the turbine blade to the turbine disk. Also, shank part (4)
An angel that fills a gap between adjacent turbine moving blades when a plurality of turbine moving blades are arranged on the circumference and forms a gas flow path at a boundary between the blade and the blade portion (2). A thin plate-shaped protrusion called a wing (14) is provided.

The fatigue test for investigating the fatigue strength of the blade portion (2) of the illustrated turbine rotor blade (10) is conducted mainly by the turbine rotor blade on the chuck portion of the jig attached to the fatigue tester which causes vertical vibration. Is supported in a cantilever manner and is oscillated at a resonance frequency peculiar to the turbine rotor blade.

Here, the conventional method for fixing the turbine rotor blade to the chuck portion is as follows: "The surface of the shank portion, which is the edge of the shank pocket, in the turbine rotation direction (16 in the figure) is attached to the blade surface by the chuck portion. It is performed by sandwiching and constraining it from a substantially normal direction (vertical direction in the figure) or by "constraining the tab tail portion and the angel wing formed on the platform portion. Note that the turbine blade is restrained to the chuck part by arranging the turbine blade between two thick plate-shaped clamps that form the chuck part and then using a plurality of bolts / nuts while keeping the two clamps in parallel. This is done by urging one clamp toward the other clamp to narrow the gap between the two clamps.

[0007]

However, the above-described conventional "method of restraining the surface of the shank portion, which is the edge of the shank pocket, in the turbine rotation direction by the chuck portion from the substantially normal direction to the blade surface. ”, The supporting area is small and it is supported by a two-dimensional surface. Due to the thinning of the shank part due to the recent weight reduction of parts, it becomes a large steady force when sandwiching and fixing it with a strong force. There are problems that the stress acts on the shank portion to cause buckling deformation in the thin-walled shank portion, and cracks due to fatigue fracture occur from a portion other than the blade portion, which is the evaluation portion. Also, in the above "method of restraining the tab tail part and the angel wing formed on the platform part", although a slight improvement can be seen compared to the method, depending on the shape of the platform part, the same evaluation as above is also obtained. There were cases where cracks occurred from parts other than the blade part.

Particularly, in a low-pressure turbine rotor blade, the blade portion is larger than the platform portion. Therefore, when the turbine rotor blade is fixed to the fatigue tester by this method, in many cases, the vicinity of the boundary between the shank portion and the tab tail portion is reached. There was a problem that cracks would occur due to fatigue fracture. Such a problem has been particularly remarkable when trying to carry out a high cycle fatigue test.

The present invention has been made in view of the above problems, in which a turbine rotor blade is strongly cantilever-supported and fixed to a chuck portion of a jig attached to a fatigue tester, and particularly a high-cycle fatigue test is performed. It is an object of the present invention to provide a support structure for a turbine rotor blade that enables the implementation of the above, and can prevent the occurrence of cracks due to fatigue fracture from the portion other than the blade portion that is the rating portion.

[0010]

According to the present invention for achieving the above object, a platform portion (7) including a shank portion (4) and a tab tail portion (6) is formed at one end of a wing portion (2), and Turbine rotor blade (10) having a ventral side shank pocket (4a) and a back side shank pocket (4b) formed on both sides of the shank portion, the recess being formed in the turbine rotation direction.
Is a supporting structure for a turbine blade for cantilever-supporting a jig (20) attached to a fatigue tester and vibrating the jig to measure the fatigue strength of the blade part. An abdominal clamp (8a) and a dorsal clamp (8b) having protrusions that fit into the recesses of the abdominal shank pocket and the back shank pocket are attached to the chuck portion of the jig that is held and supported. The ventral clamp and the dorsal clamp are inserted and fitted into the ventral shank pocket and the dorsal shank pocket, respectively, and grip the bottom surfaces of the ventral shank pocket and the dorsal shank pocket from both sides in the turbine rotation direction. (EN) A support structure for a turbine rotor blade, which is characterized in that it is fixed.

According to the present invention, a ventral clamp and a dorsal clamp which are shaped to fit in the recesses of the ventral shank pocket and the dorsal shank pocket are used, and are inserted into the ventral shank pocket and the dorsal shank pocket, respectively. Then, the bottom surface of the ventral shank pocket and the back shank pocket is fixed by grasping and fixing the bottom surfaces of the turbine rotation direction, that is, from both sides in the substantially normal direction to the blade surface, and three-dimensionally. Since the turbine rotor blade is gripped, the turbine rotor blade can be firmly cantilevered and fixed to the jig. Further, since the thin shank portion is not fixed, fatigue failure does not occur in the shank portion and the tab tail portion, and the fatigue strength test of the blade portion can be appropriately performed.

Further, the ventral clamp (8a) and the dorsal clamp (8b) further include a shank portion (in the turbine rotation direction) which is an edge of the ventral shank pocket (4a) and the dorsal shank pocket (4b). It is preferable to contact with 4) without a gap and to grip this from both sides in the turbine rotation direction.

In addition to the above, by gripping the surface of the shank portion in the turbine rotation direction, which is the edge of the shank pocket, from both sides in the turbine rotation direction, the contact area with the clamp is further increased, and the turbine blade is mounted on the jig. Can be stably supported and cantilevered. Since the clamp is inserted into the shank pocket to be in a solid state, buckling deformation or cracking does not occur in the thin-walled shank portion even if the shank portion is sandwiched and gripped by a strong force.

Here, the ventral side clamp (8a) and the dorsal side clamp (8b) are based on the three-dimensional CAD data used for the design of the turbine blade (10), and the ventral side shank pocket (4a) and Back shank pocket (4
It is preferably manufactured by calculating the shape of the depression of b) and cutting out the metal material.

The platform of the turbine blade is manufactured mainly by casting based on the design data by three-dimensional CAD. By calculating the shape of the recess of the shank pocket based on this three-dimensional CAD data, It is possible to form ventral and dorsal clamps that can fit exactly into the shape of the shank pocket. In addition,
Since the ventral and dorsal clamps, which are disposable parts, are relatively simple convex parts, they can be cut out from the material relatively easily.

In a preferred embodiment of the present invention, the abdominal clamp (8a) and the dorsal clamp (8b) are made of a high hardness aluminum metal material.

A clamp is manufactured by using an aluminum-based metal material, and the clamp is inserted into the shank pocket, fitted, and then firmly gripped, thereby causing a slight longitudinal strain and lateral strain in the clamp to form a shank pocket. The clamp can be sufficiently adhered to the recess. As a result, the turbine rotor blade is stably fixed to the jig. The reason why the high hardness aluminum material is used is that if the low hardness aluminum material is used, the clamp itself has a cushioning action, and as a result, an appropriate fatigue test cannot be performed.

[0018]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described below with reference to the accompanying drawings. 1 to 4 show a preferred embodiment of a support structure for a turbine rotor blade according to the present invention. In addition, the same reference numerals are given to the common parts in each drawing, and the duplicated description will be omitted. Here, FIG. 1 is a perspective view showing a state in which a turbine blade is cantilevered and supported by a jig, FIG. 2 is a front view thereof, and FIGS. 3 and 4 are XX sectional views and YY in FIG. 2, respectively.
A cross-sectional view is shown. The two-dot broken line in FIGS. 2 to 4 transparently represents the turbine rotor blade fixed to the jig. The turbine rotor blade cantilever-supported and fixed to this jig is the same as the turbine rotor blade shown in FIG. 6, and will be described below using the same names as the names of the parts used in [Prior Art].

The jig 20 shown in FIGS. 1 to 4 is firmly fixed on a cylinder rod (not shown) of a fatigue tester by a pedestal 22 thereof. Reference numeral 24 is a screw for fixing the pedestal 22 to the cylinder rod.

This fatigue testing machine oscillates a jig 20 fixed on the upper surface of a cylinder rod in the vertical direction, so that the turbine moving blade 10 is cantilevered and fixed to the jig to assemble the turbine moving blade. The fatigue strength of the blade portion is measured by repeatedly giving the vibration in the rotation direction at the time of the rotation, that is, in the direction of the normal line to the blade surface to continuously bend the blade portion.

By setting the vibration applied to the turbine rotor blade to the resonance frequency specific to the turbine rotor blade, a relatively large deflection can be generated in the blade portion even with a small vibration force. Further, the turbine rotor blade is fixed to the illustrated jig 20 with the ventral side of the blade surface facing upward. The amount of deflection of the wing is controlled by an optical displacement meter (not shown).

The jig 20 has an opening 26 on one surface which is a front surface thereof, a space 28 in which a platform portion of a turbine rotor blade can be arranged is formed, and a box integrally formed with a pedestal 22. The outer shape is formed by the body 32, an upper lid 34 that is attached to the opening 26 and covers a portion above the opening 26, and a lower lid 36 that covers a portion below the opening 26. The upper lid 34 and the lower lid 36 are respectively attached to the box 32 by bolts from the front surface of the opening 26.
It can be fixed to.

In the space 28, a chuck portion for cantilevering and supporting the turbine rotor blade 10 is arranged. The chuck portion is composed of a belly-side clamp 8a, a back-side clamp 8b, and a plate member 38 for fixing the belly-side clamp. The plate member 38 is attached near the upper surface in the space 28, and the belly-side clamp 8a is attached by a biasing screw 42. It has a form in which it can move integrally downward in the vertical direction. The back side clamp 8b is installed on the bottom surface of the space 28.

The plate member 38 and the back side clamp 8b are biased from the jig front surface toward the inner side of the space by the upper lid and the lower lid, respectively, and are supported so as not to come out from the opening during the test. .

Ventral clamp 8a and dorsal clamp 8b
Each has a convex portion formed. Ventral clamp 8a
Has a shape that fits with an abdominal shank pocket 4a formed of a recess formed in the shank portion 4 of the turbine rotor blade 10, and the convex portion of the back clamp 8b is formed with the back shank pocket 4b. It is shaped to fit. Note that FIG.
The specific shape of the ventral clamp is shown in (a) and the dorsal clamp is shown in (b). The protrusions of the belly-side clamp and the back-side clamp are attached to the jig with their axes aligned and facing each other.

Here, it is preferable that both the abdominal clamp 8a and the dorsal clamp 8b are made of an aluminum-based metallic material having a higher hardness and more flexible than metallic materials used for other parts. If an aluminum-based metal material is used, its manufacture is easy, and a clamp, which is a disposable component, can be provided at a relatively low cost. Further, since the aluminum-based metal material has some flexibility, it has the advantages described below when fixing the turbine rotor blade.

The abdominal and dorsal clamps are manufactured by calculating the shapes of the depressions of the abdominal shank pocket and the dorsal shank pocket based on the three-dimensional CAD data used for designing the turbine blade. It is preferably carried out by shaving. By manufacturing the ventral and dorsal clamps based on the three-dimensional CAD data of the shape of the shank pocket, it becomes possible to manufacture the convex portion of the clamp that accurately fits the recess of the shank pocket. Since the ventral and dorsal clamps are relatively simple convex parts, it is relatively easy to cut out the material.

For fixing the turbine rotor blade 10 to the chuck portion, the platform portion 7 is arranged in the space 28 so that the ventral side of the blade portion 2 faces upward, and the back side shank pocket 4b.
Is fitted to the dorsal clamp 8b, and then the convex portion of the abdominal clamp 8a fixed to the plate member 38 is inserted into the recess of the abdominal shank pocket 4a. The abdominal clamp moves vertically downward integrally with the plate material by tightening a biasing screw 42 that biases the plate material downward,
The ventral clamp and the dorsal clamp grasp the bottom surfaces of the ventral shank pocket and the dorsal shank pocket from both sides in the turbine rotation direction (vertical direction in the figure).

At this time, the clamp made of the aluminum-based metal material causes a slight longitudinal strain and a lateral strain and sufficiently adheres to the recess forming the shank pocket, so that the turbine rotor blade can be stably gripped. Further, since the convex portion of the clamp also three-dimensionally supports the side wall of the shank pocket, fatigue fracture of the thin-walled shank portion does not occur, and the fatigue strength test of the blade portion can be appropriately performed.

Further, in the abdominal clamp 8a and the dorsal clamp 8b, the surfaces 16 of the shank portion 4 in the turbine rotating direction, which are the edges of the abdominal shank pocket 4a and the dorsal shank pocket 4b, are also provided from both sides in the turbine rotating direction. It is gripped and fixed.

The surface 16 of the shank portion 4 shown in FIG. 6 is gripped by the base portion of the convex portion of the clamp, and the contact area between the clamp and the shank portion is further increased, so that the turbine blade is firmly fixed to the jig. Can be cantilevered and fixed.

In the jig of this embodiment, the tab tail portion 6
A support member 44 is provided to support the. By supporting not only the shank portion 4 but also the tab tail portion 6 by the support member 44, the force applied to the shank portion during the vibration test can be dispersed / reduced and the fatigue fracture from the shank portion can be sufficiently suppressed. it can. The support member 44 is preferable for stably supporting the turbine rotor blade 10 in a cantilever manner, but is not essential as the configuration of the present invention.

The present invention is not limited to the above-mentioned embodiments, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

[0034]

As described above, according to the present invention, the turbine rotor blade is firmly cantilevered and fixed to the chuck portion of the jig attached to the fatigue tester, except for the blade portion which is the evaluation portion. (EN) Provided is a support structure for a turbine rotor blade, which prevents the occurrence of cracks due to fatigue fracture from a part and enables appropriate execution of a particularly high cycle fatigue test.

[Brief description of drawings]

FIG. 1 is a perspective view showing a state in which a turbine blade is cantilevered and supported by a jig.

FIG. 2 is a front view of a jig in this example.

FIG. 3 is a sectional view taken along line XX in FIG.

FIG. 4 is a sectional view taken along line YY in FIG.

FIG. 5 is a perspective view showing specific shapes of an abdominal clamp and a dorsal clamp.

FIG. 6 is a perspective view showing a turbine rotor blade.

[Explanation of symbols]

2 wings 4 Shank part 4a Ventral shank pocket 4b Dorsal shank pocket 6 Tab tail part 7 Platform Department 8a Ventral clamp 8b Dorsal clamp 10 turbine blades 14 angel wings 20 jigs 22 pedestal 24 screws 26 opening 28 space 32 boxes 34 Upper lid 36 Lower lid 38 Plate material 42 biasing screw 44 Support material

Claims (4)

[Claims] 1. An abdomen formed on one end of the blade (2) with a platform portion (7) consisting of a shank portion (4) and a tab tail portion (6), and on both sides of the shank portion comprising depressions in the turbine rotation direction. Side shank pocket (4a)
And a jig (20) in which a turbine blade (10) having a back shank pocket (4b) is attached to a fatigue tester.
A turbine rotor blade supporting structure for cantilever-supporting and measuring the fatigue strength of the blade portion by vibrating this, wherein the chuck portion of the jig for cantilever-supporting the turbine rotor blade is An abdominal clamp (8) having a convex portion that fits into the depressions of the abdominal shank pocket and the back shank pocket (8
a) and a dorsal clamp (8b) are attached, the abdominal clamp and the dorsal clamp being inserted and fitted into the abdominal shank pocket and the dorsal shank pocket, respectively. A support structure for a turbine rotor blade, characterized in that the bottom surface of the side shank pocket is gripped and fixed from both sides in the turbine rotation direction. 2. The shank portion in the turbine rotation direction, which is the edge of the ventral side shank pocket (4a) and the back side shank pocket (4b), of the ventral side clamp (8a) and the dorsal side clamp (8b). The support structure for a turbine rotor blade according to claim 1, wherein the support structure is in contact with 4) without any clearance and is gripped from both sides in the turbine rotation direction. 3. The ventral clamp (8a) and the dorsal clamp (8b) are based on the three-dimensional CAD data used for designing the turbine blade (10), and the ventral shank pocket (4a) and the dorsal clamp (8a). The turbine rotor blade support structure according to claim 1 or 2, which is manufactured by calculating a shape of a recess of the side shank pocket (4b) and shaving a metal material. 4. The turbine rotor blade support according to claim 1, wherein the ventral side clamp (8a) and the back side clamp (8b) are made of a high hardness aluminum-based metal material. Construction.