JPS6079104A - Moving blade for turbo type hydraulic machine - Google Patents

Abstract

PURPOSE:To prevent vibration of a blade base part, by a method wherein the side end face in peripheral direction of a blade base part, supporting the profile part of a moving blade, is slanted in the direction of axis of a rotary disc, a cut part is formed in the intermediate part of a slanted end face, and is forced into frictional contact with the cut part in the adjoining blade base part. CONSTITUTION:A number of blades 12, aligned in a row manner along the peripheral direction, are implanted along the peripheral direction in the outer periphery of the rotary disc 11 of a rotor 10, and each blade 12 is integrally provided with a dove-tail grooved mounting part 15, engaging with a dove-tail groove in the outer peripheral part of the rotary disc 11, a blade base part 16, and a profile part 17 implanted in said part 16. In which case, side faces 18 and 19, in the peripheral direction of the rotor 10, of the blade base part 16 are slanted at angles of theta1 and theta2, respectively, with the direction of axis of the rotor 10. Further, cut parts 20 and 21, each serving as an intermediate connection part sand additionally acting as a frictional contact surface, are formed in the intermediate parts of the slanted side end faces 18 and 19. Frictional contact between the cut parts 20 and 21 in the adjoining blade base parts 16 causes restriction of the blade base part 16 from vibration.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] This invention relates to a rotary blade of a turbo-type fluid machine, and particularly relates to an improvement in the support groove structure of a rotary blade equipped with a friction-type vibration suppressing device on the base of the blade. .

[Technical background of the invention and its problems]

Generally, turbo-type fluid machines are applied to axial-flow rotating machines such as gas turbines and steam turbines, and the rotating blades are formed by installing a large number of blades in rows in the circumferential direction in the circumferential groove of a rotating disk. , am is made. In the rotary blades of conventional turbo-type fluid machines, vibrations occur because the working fluid violently collides with the blade platform and airfoil part during high-speed rotation of the blades, and this vibration causes significant damage to the blades, resulting in breakage. However, due to the excitation of the blade, various vibration modes are generated within the blade platform.
There were problems such as part of the wing platform breaking.

When vibrations occur in the blade, not only the blade platform but also the airfoil can be damaged and broken. For example, as a result of vibrations caused by airfoils, portions of the airfoil often break or become damaged due to fractures in the corners of the vane platform or various cracks.

The damage caused by the vibration of the blade has a significant negative impact on the effective life of the blade, and therefore it is necessary to suppress the vibration of the blade platform.

As a conventional vibration damping device for the blade platform of a rotating blade, there is a vibration damping device that uses a core and a coil inserted into a storage groove of a rotating disk to damp vibrations of the blade. However, this vibration damping device has a large number of parts, and the assembly work is complicated and time-consuming, and there is a risk of parts being lost. When the above-mentioned vibration damping device is provided, a vibration damping core and a coil storage groove must be formed in the rotary disk separately from the circumferential groove for implanting the blades, which complicates the machining of the rotary disk.

Furthermore, as another vibration damping device, there is one in which a pin with a notch is interposed between the vane base parts, and vibration is damped by the rotation of the pin due to the moment generated in the pin. The notch part breaks due to wear and fatigue, and the vibration damping function is impaired.A notch pin is required between each vane plate part to damp vibration, which increases the number of parts and increases weight and cost. There were problems such as.

Furthermore, as shown in Fig. 1, in the rotary blade of a conventional turbo-type fluid machine, due to performance constraints of the fluid machine, the blade trailing edge 2 must be extended from the rectangular blade platform 1. Sometimes there isn't. In this case, the trailing edge portion 2 of the blade 3 naturally suffers from insufficient strength.

By the way, the rotating blade shown in FIG. 1 has a shape in which the trailing edge 2 of the blade rests on the adjacent blade pedestal 1, so the vibration of the blade pedestal 1 is transmitted to the adjacent blade through the trailing edge 2. It is transmitted to the vane platform section 1. For this reason, the vibration of one wing platform section 1 may interfere with the adjacent wing platform section 1 and cause damage. In order to prevent the interference of the vane platform part 1, it is possible to prevent the blade trailing edge part 2 from protruding by widening the pitch in the circumferential direction of the vane platform part 10 or by changing the cross-sectional shape of the blade. , the performance of the fluid machine will deteriorate, which is undesirable.

For this reason, there is a strong desire for a vibration suppression device that suppresses and reduces the vibration of the vane table without increasing the number of parts, weight, cost, or complicating assembly work. In addition, there are expectations for a rotary blade support groove structure that prevents the trailing edge of the blade from protruding from the blade platform without changing the blade shape of the rotary blade or the blade row pitch of the blade.

[Purpose of the invention]

In consideration of the above-mentioned points, this invention effectively and reliably suppresses the vibration of the vane pedestal part by using a friction contact structure that is simple and easy to assemble without increasing the number of parts. It is an object of the present invention to provide a rotating blade for a turbo fluid machine that prevents the blade from protruding from the part.

[Summary of the invention]

In order to achieve the above-mentioned object, the rotating blade of the turbo-type fluid machine according to the present invention is formed by forming a plurality of blades on the outer periphery of a rotating disk in an O-shape along the circumferential direction. The circumferential side end surface of the vane platform that supports the airfoil portion of the blade is angled in the axial direction of the rotating disk, and this notch is in frictional contact with the notch of the adjacent vane platform. It is.

[One embodiment of the invention]

Hereinafter, preferred embodiments of the rotary blade i for a turbo fluid machine according to the present invention will be described with reference to the accompanying drawings.

FIGS. 2 to 4 show a rotating blade of a turbo fluid machine according to the present invention, and this rotating blade has a large number of blades 12 arranged in the circumferential direction on the outer periphery of a rotating disk 11 serving as a rotor 10. /a ＼ Sha is formed by being planted in rows along the line. The rotating disk 11 has a circumferential groove [3 on its outer peripheral edge, and a dovetail portion 13a is formed in the circumferential groove [3, while at least a portion of the circumferential groove 13 in the circumferential direction is formed with a dovetail portion 13a. , A) A notch [3b communicating with the groove 13& is formed in the radial direction. The blade [2 is taken in and taken out through this notch 13b.

The blade 12 has a dovetail-shaped attachment part [5] that engages with the dovetail groove 13m, a blade platform part [6, and an airfoil part [7] implanted in the blade platform [6] integrally or integrally. and feather 1
2 is inserted into the circumferential groove [3 from the notch 13b by the dovetail groove-shaped mounting portion [5] and is slidably held.

The vane platform [6 has side end surfaces ts and t9 in the circumferential direction of the rotor (rotating disk) EO, and these side end surfaces [8 and [9] have angles θ1 and θ2 with respect to the axial direction of the rotor [O]. Only sloping.

Although it is desirable that the inclination angles θ1 and θ2 be substantially equal to each other in terms of manufacturing the vane platform portion 16, they are not necessarily limited to being equal. In addition, the inclined end surfaces 18 and 19 of the blade platform section 6
A notch 20.21 is formed in the middle of the groove as an intermediate connecting portion that also serves as a frictional contact surface. The notches 21 and 21 are adjacent to each other (opposed to the notches 21 and 21 on the inclined surface of 6), and the opposing notches 21 and 21 are brought into close contact with each other, There is frictional contact. Cut portion addition, 21
intersect the inclined end surfaces [8, 19 at angles θ3, θ4, and the side end surfaces of the vane platform portion 16 are generally formed in a two-shape or a zigzag shape.

Further, the vane platform portion 16 is adjacent to the leading vane platform portion 16, and the working fluid flow path n is formed between the airfoil portions 17 and 17 of the blade 12.
is formed. End surfaces 24.25 are also formed on the front and rear sides of the rotor 1o in the axial direction. It engages with the circumferential surface of the groove [3, and axial movement of the blade 12 is restricted.

By the way, the blade platform [6 is the circumferential side end surface [8, 19
By purchasing it as an inclined end surface, one diagonal of the vane platform portion 16 becomes longer than the other diagonal.

Therefore, by arranging the rotary blade so that the direction from the leading edge 12m of the blade to the trailing edge 12b is a long diagonal direction, the trailing edge 12b of the blade protrudes from the blade platform [6]. You can prevent it from happening.

This reinforces the strength of the root portion of the blade 12.

In one mode, the rotor 100 vibrates relative to the adjacent blade table 16 in the radial direction, and in another shooting mode, the blade table 16 vibrates relative to the adjacent blade table 16 in the circumferential direction. It may also move relative to.

Since the notches provided on the inclined end surface [8.19 of each blade platform 16 and 21 are in close contact with each other, when the blade platform 16 vibrates in the radial direction, the opposing notches Canada, 21
are in frictional contact in the radial direction, suppressing the sliding movement of the vane platform [6] in the radial direction. In addition, when the blade platform part 16 vibrates in the circumferential direction, if the blade platform part [6 moves to the left side in FIG. It meshes strongly with the notch part and makes frictional contact, and a clockwise twist acts on the vane platform [6]. Due to this torsional force, the front end surface U of the vane platform [6]
is strongly pressed against the circumferential side of the On the other hand, if the vane base part [6 moves to the right side due to the circumferential vibration, the notch part engages strongly with the notch part 21 of the adjacent vane base part t6, and the vane base part [6] moves to the right side due to the circumferential vibration.
A torsional force 9 of the left rotation 9 acts on 6. Due to this twisting force, the rear end surface 5 of the vane platform portion L6 is pressed against the circumferential surface of the circumference $13 of the rotating disk 11, and comes into frictional contact. In this way, the blade base portion E6 is in strong frictional contact with the notch portion 21 in both radial and circumferential vibration modes, and acts to suppress and damp vibration. Therefore, the notch 21 functions as a vibration suppressing device that suppresses and reduces the vibration of the vane platform L6.16.

Furthermore, in this rotary blade, the circumferential side end surface [8.19 of the blade platform part [6] extends from the blade leading edge 12m to the trailing edge 1.
2bK, and since the blade 12 is disposed in the long diagonal direction of the blade platform 6, the trailing edge 12b of the blade does not overhang or protrude from the blade platform 6. do not have. Furthermore, unlike the case where the shape of the vane platform 16 is a simple rhombus, sufficient circumferential dimension (width) of each vane platform 16 can be ensured, so that the root part of the blade attachment part lacks strength. This can be effectively prevented, and there is no need to change the shape of the rotary blades or the pitch between the blades, so the performance of the fluid machine can be maintained sufficiently.

Next, a modification of this invention will be described.

The rotary blade shown in this modification has a notch 2 in the inclined end face 18, 19 of the blade 12, as shown in FIGS. 5 and 6.
The structures of 0A and 21A are fundamentally different from those described in one embodiment. Since the other structures are the same, they are given the same reference numerals and their explanation will be omitted.

The notches 2OA and 21A formed in the middle part of the sloped end surface 8.19 of the blade 2 are relative to the axial direction of the rotor 1O.

They are inclined by angles θ5 and θ6. It is desirable that the inclination angles θ5 and θ6 are equal to each other. In this way, the notch part ram 21A has sloped surfaces of angles θ5 and θ6, and the notch parts 2OA and 21A having the sloped surfaces are brought into close contact with each other and brought into frictional contact, thereby increasing the frictional contact area. is increased, the meshing of the adjacent vane platform portions i6 is made stronger, and the effect of suppressing and damping vibrations can be further enhanced.

In the detailed explanation of the present invention, an example was explained in which two-shaped or zigzag-shaped notches were formed on the inclined end face of the vane platform, but it is also possible to apply a wear-resistant treatment to the contact surface of the notch. , a friction-increasing substance may be attached by baking, etc. In addition, when the notch has an inclined surface, as shown in Fig. 6, the direction of inclination of one inclined surface of the vane platform section is made different from the other inclined surface shown by a solid line, as shown by a broken line. Good too.

〔Effect of the invention〕

As described above, in the rotating blade of a turbo-type rotating machine according to the present invention, the circumferential end surface of the blade platform that supports the airfoil portion of the blade is inclined with respect to the axial direction of the rotating disk. A side end face is configured, and a bi-shaped or zigzag-shaped notch is formed in the middle part of the inclined side end face, and by bringing this notch into frictional contact with the notch of the adjacent blade platform, Even if vibration occurs in either the radial or circumferential direction in the vane mount due to the action of the working fluid during rotation of the rotary blade, the vibration is suppressed by frictional contact between the vane mount through the notch. , acts to attenuate it. Vibration in the vane platform is suppressed through frictional contact at the notch, and since this notch functions as a vibration suppressor, there is no need to add a new vibration suppressing member, the number of parts is small, and the rotary vane The assembly work can be done simply and easily, eliminating the factors that increase weight and cost.

In addition, since the circumferential end surface of the vane platform is inclined with respect to the axial direction of the rotating disk and is formed as an inclined end surface, one diagonal of the vane platform is longer than the other diagonal, and the long diagonal By arranging the airfoil portion of the vane along the ridge, it is possible to effectively prevent the trailing edge from overhanging and protruding from the vane platform. Therefore, the strength of the root portion of the blade is increased and the life of the blade is extended. □

[Brief explanation of drawings]

FIG. 1 is a plan view showing an example of a rotary blade of a conventional turbo-type fluid machine, FIG. 2 is a partial perspective view showing an example of a rotary blade of a turbo-type fluid machine according to the present invention, and FIG. is a perspective view showing the blade structure of the rotary blade according to the present invention;
The figure is a plan view of the assembled rotating blade (13), and FIGS. 5 and 6 are a perspective view and a side view showing a modification of the present invention. 0...Rotor%11...Rotating disk%12-...Blade, 2a...Blade leading edge, L2b...Blade trailing edge, 13...Circumferential groove, 15... ... Attachment part, ``6... Wing platform part, 17... Airfoil part, 18.19... Side end surface (slanted end surface), Rod, 2OA, 21.21 Person... Notch part, A...front end surface, 5...rear end surface. Representative Patent Attorney Noriyuki Chika (and 1 other person) (14) Figure 1 Figure 2 7 JP-A-Sho GO-79104 (5) Figure 3 223 2 Figure 4 24 17 19 17 24

Claims (1)

[Scope of Claims] 1. In a rotary blade of a turbo-type fluid machine in which a plurality of blades are installed in a row along the circumferential direction on the outer periphery of a rotating disk, a blade platform that supports the airfoil portion of the blade. The circumferential side end face of the part is
An inclined end face is formed by being inclined with respect to the axial direction of the rotating disk, and a notch serving as an end face connection part is formed in the middle part of the inclined end face, and this notch is connected to the adjacent blade platform part. A rotating blade for a turbo fluid machine characterized by being in frictional contact with a notch. 2. The notch part of the inclined end face has a shape of 2, and is inclined with respect to the radial direction of the rotating disk so that the frictional contact area is large. The rotating blade of the machine. 3. The inclined end surface of the blade platform is inclined in the direction from the leading edge of the blade to the trailing edge of the blade, and the airfoil portion is disposed along the long diagonal direction of the blade platform. The rotating blade of the turbofluid machine according to item 1. 4. The rotating blade of a turbo-type fluid machine according to claim 1 or 2, wherein the friction contact surface of the cut portion of the slanted end surface is subjected to wear-resistant treatment.