JP2005155333A - Fixing structure for turbine moving blade - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing structure for turbine moving blades capable of securely fixing the turbine moving blades relative to a rotor disk by simple processing and simple-shaped components. <P>SOLUTION: This fixing structure of the turbine blades is equipped with a recessed groove part 10 in a circumferential direction provided on an outer surface of the rotor disk 1; a notched part 20 having an approximately L-shaped cross section, equipped with a penetrating part 21 notching one end part of a platform 5 in a radial direction and a lateral groove part 22 extending from the penetrating part 21 in the circumferential direction, and provided on the platform 5 so as to superpose an outer peripheral side of the recessed groove part 10 in a predetermined assembling position; and a stop key 30 having a key main body part 31 inserted into a key space part 23 and formed to have a approximately L-shaped cross section. The stop key 30 is inserted from the penetrating part 21 and slid in the circumferential direction, and the key main body part 31 is inserted into the key space part 23. After that, a caulking part 40 is formed in an appropriate position of an upper face part of the platform 5 to prevent the stop key 30 from coming out. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a turbine rotor blade fixing structure applied to a rotary machine such as a steam turbine or a gas turbine provided with a side entry type rotor blade.

  Conventionally, a rotating machine such as a steam turbine or a gas turbine has a configuration in which a large number of turbine blades (hereinafter referred to as “moving blades”) that protrude radially from the circumferential surface of a rotor disk are arranged close to each other in the circumferential direction. It has. Such a moving blade is incorporated by inserting a blade root from the rotor axial direction into a blade groove provided on the circumferential surface of the rotor disk. In the case of such a side-entry type moving blade, after the moving blade has been assembled, it is necessary to take an axial retaining (fixing) measure in order to prevent the moving blade from moving in the axial direction of the rotor.

As the above-described measures for preventing the blades from coming off, that is, for fixing the turbine blades, a structure using pins inserted from the blade base across the rotor disk is conventionally known.
In addition, for example, as in the case of an integral shroud in which the top shroud is formed integrally with the moving blade and the shroud is an occlusal type, all the moving blades (total number) must be inserted in the rotor axial direction to some extent in advance. In the case of a structure that cannot be assembled, the above-described fixing structure using a pin cannot be employed. Therefore, a structure for fixing a moving blade using, for example, a part called a locking piece has been proposed. The locking piece in this case is a fan-shaped component obtained by dividing a donut-shaped plate-like member (see, for example, Patent Document 1).
JP-A-6-137104 (see paragraphs [0009] to [0011] and FIG. 1)

However, in the case of the turbine rotor blade fixing structure using the locking piece described above, it is necessary to form a space for inserting the locking piece over the entire circumference of the rotor disk. For this reason, it is necessary to perform troublesome grooving of complex machining shapes on both ends of the blade root and both ends of the rotor disk over the entire circumference, which is disadvantageous in terms of machining man-hours and costs. .
Further, in addition to the increase in the number of the above-described locking pieces, the yield is poor because of the fan-shaped shape that is difficult to process. Therefore, this point is also a factor in increasing the cost.
Furthermore, the above-mentioned locking piece is inserted into a space sequentially from an insertion window provided in a proper position and fed in the circumferential direction. However, after being inserted over the entire circumference, the locking piece does not come out of the insertion window. It was necessary to fix the adjacent objects at the position of the insertion window by spot welding or the like.

As described above, the conventional turbine blade fixing structure using the locking piece requires complicated and costly processing and parts, so that the turbine can be securely fixed by simplifying the shape and processing of the parts. A moving blade fixed structure is desired.
The present invention has been made in view of such circumstances, and an object of the present invention is to reliably fix the turbine rotor blade to the rotor disk by simple processing and parts having a simple shape. An object of the present invention is to provide a turbine rotor blade fixing structure that can be used.

In order to solve the above problems, the present invention employs the following means.
The turbine rotor blade fixing structure according to the present invention is a turbine motion that prevents side entry type turbine rotor blades assembled by inserting blade roots into rotor blade blade grooves from the rotor axial direction from moving in the rotor axial direction. A wing fixing structure,
A circumferential groove in the outer surface of the rotor disk;
Provided on the platform of the turbine rotor blade, and having a substantially L-shaped cross-sectional shape including a through-portion in which one end of the platform is cut out in a radial direction and a lateral groove extending in the circumferential direction from the through-portion. A notched portion that overlaps with the outer peripheral side of the concave groove at the assembly position;
A key body portion inserted into a key space portion formed between the concave groove portion and the lateral groove portion, and a key fixing portion inserted across the penetration portion and the concave groove portion, and having a substantially L shape. A stop key formed in a cross-section and provided for each turbine blade,
The locking key is inserted from the through portion and slid in the circumferential direction, and after inserting the key body portion into the key space portion, a caulking portion is formed at an appropriate position on the upper surface of the platform to prevent the locking key from coming off. It is characterized by that.

According to such a turbine blade fixing structure, at a predetermined assembly position, the concave groove portion on the rotor disk side and the lateral groove portion on the turbine blade side overlap in the circumferential direction to form a key space portion. And by providing the penetration part communicating with the key space part, the stop key can be inserted into the penetration part from the outer peripheral side of the platform and slid in the circumferential direction. As a result, the key body part of the stop key can be easily Can be inserted into the key space. In this state, a caulking portion that engages with the key fixing portion is formed at an appropriate position on the upper surface portion of the platform, and if sliding in the circumferential direction is prevented, the locking key can be easily fixed with a simple tool to provide a reliable retaining prevention. be able to.
Furthermore, since the stop key inserted into the penetrating part and the key space part is engaged with both the rotor disk and the turbine rotor blade, relative movement of the rotor disk and the turbine rotor blade in the rotor axial direction can be prevented. it can.

  In the turbine blade fixing structure of the present invention, it is preferable to provide a chamfering assisting chamfered portion in the key fixing portion of the locking key, thereby locking the key fixing portion by a simple caulking operation. Since the caulking portion can be easily formed, the stop key can be securely fixed and prevented from coming off.

According to the turbine blade fixing structure of the present invention described above, a simple operation of inserting the key body portion into the key space portion by inserting the stop key from the platform outer periphery side of the turbine blade and caulking the upper portion of the platform. As a result, the stop key can be fixed and prevented from coming off, and the turbine rotor blade can be securely fixed at a predetermined assembly position by the stop key.
In addition, the rotor disk concave groove, the turbine blade notched portion and the stop key required for such a fixed structure are like a rectangular cross section formed by a plane compared to the conventional structure using a locking piece. Simple grooving and simple shaped parts. Therefore, since the number of processing steps is reduced in addition to the improvement in yield, it is possible to provide an inexpensive fixing structure while suppressing processing costs.

Hereinafter, an embodiment of a turbine blade fixing structure according to the present invention will be described with reference to the drawings.
FIG. 2 is a schematic configuration diagram of the main part of the rotor disk as seen from the axial direction. A large number of blade grooves 2 arranged at equal pitches in the circumferential direction are provided on the outer surface 1 a of the rotor disk 1. The blade groove 2 is a concave groove formed in the same cross-sectional shape as a tree-shaped blade root described later. The axis of the blade groove 2 is inclined at an appropriate angle from the axial direction of the rotor disk 1.
On the other hand, the turbine rotor blade (hereinafter referred to as “the rotor blade”) 3 includes a blade body 4, a platform 5, and a blade root 6. The rotor blade 3 is assembled by inserting a blade root 6 having a tree-like cross-sectional shape with an inclined axis similar to the blade groove 2 into the blade groove 2 from the rotor axial direction. Such a moving blade 3 is called a side entry type. The side-entry type rotor blade 3 is a rotor blade of the entire circumference, such as an integral shroud, in which a shroud (not shown) is integrally provided at the tip (top) of the blade body 4 and is engaged. This is effective in the case where the three cannot be assembled due to interference with each other unless they are simultaneously inserted.

  In order to prevent the side entry type moving blade 3 assembled by inserting the blade root 6 from the rotor axial direction into the blade groove 2 of the rotor disk 1 in FIG. A fixing structure is required to prevent the removal as shown. Therefore, a circumferential groove 10 provided on the outer surface 1a of the rotor disk 1, a substantially L-shaped notched portion 20 provided on the platform 5 of each rotor blade 3, and a substantially L-shaped cross section are formed. The fixed structure of the moving blade 3 is constituted by the stop key 30 provided for each moving blade 3.

As shown in FIG. 4, the recessed groove portion 10 is a circumferential groove portion provided in the outer surface 1 a of the rotor disk 1. The recessed groove portion 10 is obtained by performing groove processing with a predetermined width W1 over the entire circumference of the rotor disk 1 on the outer peripheral surface 1a excluding the recessed portion where the blade groove 2 is formed (FIG. 4B). )reference).
The main purpose of the concave groove portion 10 is to form two step surfaces 11 that face each other in the rotor axial direction. Therefore, the width W1 of the concave groove portion 10 is the axial thickness (width) W of the rotor disk 1. Small enough compared to. The axial position of the outer surface 1a on which the concave groove portion 10 is provided is not particularly limited, but the position where the presence of the rotor blade body 4 is least likely to be an obstacle when the stop key 30 is inserted, that is, It is preferable to be near the end in the axial direction, and in the illustrated example, it is provided at a position of a length L close to the end surface in the axial direction.

  As shown in FIG. 5, the notched portion 20 includes a radial through portion 21 provided in the platform 5 of each rotor blade 3, and a lateral groove portion 22 extending in the circumferential direction from the lower end side of the through portion 21. And a groove processed portion formed in a substantially L-shaped cross section. The notch processed portion 20 coincides with the concave groove portion 10 described above at a predetermined assembly position and overlaps in the radial direction, that is, the notch processed portion 20 is overlapped on the outer peripheral side above the concave groove portion 10 to stop the key 30. Is provided in the vicinity of the end portion in the axial direction having a length L from the end surface in the axial direction.

  The penetrating portion 21 is cut so that the circumferential end of the platform 5, that is, the side end where a large number of moving blades are adjacent to each other, penetrates from the upper end surface to the lower end surface with the same width W 1 as the concave groove portion 10 described above. This is a groove processing portion having a rectangular cross section. By providing such a penetrating portion 21, two step surfaces 21 a that face each other in the rotor axial direction are formed on the platform 5. In addition, about the circumferential direction length of the penetration part 21, the short length Ls of the center side far from an axial direction end surface should just be set so that the operation | work which inserts and inserts the stop key 30 mentioned later may be performed.

The lateral groove portion 22 forms a key space portion 23 that extends from the lower end side of the penetrating portion 21 to the inner side in the circumferential direction (center side of the blade root 6) in cooperation with the concave groove portion 10 described above. The upper end surface of the portion 23 is processed so as to function as the locking surface 24 of the locking key 30. In other words, the lateral groove portion 22 having the locking surface 24 has the same width W1 as that of the penetrating portion 21, and the locking key 30 described later is securely locked with respect to the circumferential length Lr. As long as the locking surface 24 that secures an area that does not escape upward is formed, it is sufficient.
In the example shown in the drawing, the root end portion where the axial end surface side of the blade root 6 whose axis is inclined is integrally connected to the platform 5 is partially cut so as to form the same surface as the lower surface of the platform 5. A lateral groove portion 22 having a stop surface 24 and having a width W1 as a whole is formed. That is, a part of the blade root 6 is removed by groove processing, and the key space portion 23 is formed so as to extend the space having the same cross-sectional shape as the concave groove portion 10.

The stop key 30 is an integral part formed in a substantially L-shaped cross section by a key main body portion 31 and a key fixing portion 32 provided perpendicularly from the key main body portion 31. The key body portion is a portion that is inserted into a key space portion 23 formed by the recessed groove portion 10 and the lateral groove portion 20 and functions as a retaining key for the retaining key 30 itself. Note that the same number of stop keys 30 as the moving blades 3 are required.
The key main body 31 has a rectangular cross section with a width W1 and a thickness H. The width W <b> 1 in this case is the same as that of the concave groove part 10, the penetrating part 21, and the lateral groove part 22 described above. Further, the thickness H of the key body portion 31 coincides with the height from the bottom surface of the recessed groove portion 10 to the locking surface 24 of the lateral groove portion 22 in the assembled state of the rotor blade 3, that is, the depth H of the recessed groove portion 10. ing. Therefore, it becomes the same cross-sectional shape as the rectangular cross section of the key space part 23 equal to the cross-sectional shape of the recessed groove part 10. FIG. The key main body 31 has an insertion surface 31 a set to the same length Lr as the locking surface 24.

The key fixing portion 32 is a portion that is inserted into the penetrating portion 21 and engages with the step surface 11 of the recessed groove portion 10 and the step surface 21 a of the platform 5.
Since the illustrated key fixing portion 32 is provided with chamfered portions 33 on both end surfaces in the rotor axial direction, the remaining end surface 32 a engages with the step surface 21 a of the penetrating portion 21. Further, an end surface 32 b having a height H continuous from the lower end portion of the key fixing portion 32 not provided with the chamfered processing portion 33 to the key main body portion 31 is engaged with the step surface 11 of the concave groove portion 10. The total length La of the end face 32b is set to a value smaller than the short circumferential length Ls of the penetrating portion 21, and the total height Ha of the stop key 30 is the sum of the depth of the recessed groove portion 10 and the thickness of the platform 5. The value is matched with the value.

The chamfered portion 33 is provided for the purpose of facilitating the formation of the caulking portion 40 that fixes the locking key 30 by plastically deforming the upper surface portion of the platform 5 by punching or the like. That is, since the inclined surface with respect to the stop key insertion direction is formed by forming the chamfered portion 33, it is compared with the case where the caulking portion 40 is formed between the orthogonal surface without the chamfered portion 33. Easy and reliable caulking can be achieved with simple work.
In the above description, for example, the width of the key body 31 and the width of the recessed groove 10 are both equal to W1, but in reality, including other parts, it is easily incorporated by taking into account dimensional tolerances. Possible dimension setting.

Hereinafter, the fixing work method of the above-described fixing structure will be described according to work procedures.
First, the blade root 6 of the rotor blade 3 is inserted from the rotor axial direction to a predetermined assembly position in each blade groove 2 of the rotor disk 1 in which the concave groove portion 10 is formed. As a result, the recessed groove portion 10 and the notched portion 20 overlap in the radial direction without being displaced in the rotor axial direction.
The moving blade 3 in this case may be a side-entry type moving blade having a structure that cannot be assembled unless all the blades are inserted over the entire circumference, or a side-entry type moving blade that can be fixed by sequentially mounting the moving blades 3. It may be.

After the moving blade 3 is thus inserted to a predetermined assembly position, the stop key 30 is inserted into the cutout processing portion 20 from the outer peripheral side of the platform 5. At this time, since the length Ls of the penetrating portion 21 is larger than the entire length La of the stop key 30, it can be easily inserted from above the penetrating portion 21 until it reaches the bottom surface of the recessed groove portion 10.
Next, the key body 31 is inserted into the key space portion 23 by sliding the retaining key 30 inserted into the penetration portion 21 toward the center of the blade root 6. As a result, since the insertion surface 31a of the key main body 31 is located below the locking surface 24, the stop key 30 is prevented from moving in the insertion direction and is prevented from coming off.

Further, the end surface 32a of the stop key 30 is inserted into the recessed groove portion 10 on the rotor disk 1 side and engages with the step surface 11, and the end surface 32b of the stop key 30 passes through the platform 5 on the moving blade 3 side to form a step. Since it is engaged with the surface 21a, the rotor disk 1 and the rotor blade 3 are prevented from moving relative to each other in the axial direction of the rotor by the stop key 30 having an integral structure. That is, the blade root 6 of the rotor blade 3 inserted into the blade groove 2 of the rotor disk 1 is prevented from moving out in the rotor axial direction.
Finally, if the upper surface of the platform 5 is caulked by punching, caulking or the like to form the caulking portion 40 to prevent the stop key 30 from sliding in the circumferential direction, the key body portion 31 is inserted into the key space portion 23. Can be fixed to the state.

In this way, the operation of forming the caulking portion 40 after inserting the stop key 30 from the penetration portion 21 into the notch processing portion 20 and further sliding the stop key 30 to insert the key body portion 31 into the key space portion 23 is performed. By repeating, all the moving blades 3 can be fixed easily and reliably.
The concave groove portion 10 necessary for such a fixing structure is a groove processing which is relatively easy and requires fewer processing steps since the outer surface 1a of the rotor disk 1 is subjected to a groove processing of a rectangular cross section. Further, the notched portion 20 formed by the penetrating portion 21 penetrating the platform 5 and the lateral groove portion 22 in which a part of the blade root 6 is notched is also easy to process because the processing shape is relatively simple. Less processing steps are required.
Furthermore, the stop key 30 also has a shape that combines rectangular cross sections formed of a plane as a whole, so that it can be easily processed and the yield can be improved.

  Accordingly, the shape and processing of the parts are simplified, that is, the processing parts and processing that are complicated and costly are unnecessary, so that reliable fixing can be performed at low cost. In addition, since the locking key 30 is fixed by the caulking portion 40 that can be implemented by punching using a simple tool, the workability is improved as compared with the conventional fixing by spot welding which requires a large-scale device. Is greatly improved.

  Further, when it is necessary to remove the moving blade 3 for repair or the like, the fixing by the caulking portion 40 is released, and the stop key 30 may be pulled out in the reverse procedure of the above-described fixing. It is extremely simple in comparison.

It is a figure which shows one Embodiment of the fixed structure of the turbine rotor blade which concerns on this invention, (a) is the top view which looked at the turbine rotor blade from the outer peripheral side, (b) is along the AA line of (a). FIG. It is the front view which looked at the turbine rotor blade assembled | attached to the rotor disk from the rotor axial direction. It is a figure which shows the stop key of FIG. 1, (a) is a side view, (b) is a top view, (c) is a perspective view. It is a figure which shows the rotor disk of FIG. 1, (a) is a top view, (b) is sectional drawing seen along the BB line of (a). It is a figure which shows the turbine rotor blade of FIG. 1, (a) is a top view, (b) is sectional drawing seen along CC line of (a).

Explanation of symbols

1 Rotor disc 1a Outer surface
2 Blade groove 3 Turbine blade (robot)
4 Blade Body 5 Platform 6 Blade Root 10 Concave Groove 11 Stepped Surface 20 Notch Processed Part 21 Through Part 21a Stepped Surface 22 Horizontal Groove Part 23 Key Space Part 24 Locking Face 30 Locking Key 31 Key Body Part 32 Key Fixing Part 33 Chamfering Processing part 40 Caulking part

Claims (2)

A turbine rotor blade fixing structure for preventing side entry type turbine blades assembled by inserting blade roots into rotor blade blade grooves from the rotor axial direction, and moving in the rotor axial direction,
A circumferential groove in the outer surface of the rotor disk;
Provided on the platform of the turbine rotor blade, and having a substantially L-shaped cross-sectional shape including a through-portion in which one end of the platform is cut out in a radial direction and a lateral groove extending in the circumferential direction from the through-portion. A notched portion that overlaps with the outer peripheral side of the concave groove at the assembly position;
A key body portion inserted into a key space portion formed between the concave groove portion and the lateral groove portion, and a key fixing portion inserted across the penetration portion and the concave groove portion, and having a substantially L shape. A stop key formed in a cross-section and provided for each turbine blade,
The locking key is inserted from the through portion and slid in the circumferential direction, and after inserting the key body portion into the key space portion, a caulking portion is formed at an appropriate position on the upper surface of the platform to prevent the locking key from coming off. Turbine rotor blade fixing structure characterized by that.   2. The turbine rotor blade fixing structure according to claim 1, wherein a chamfering assisting chamfered portion is provided in a key fixing portion of the stop key.

Images