JPS5925088B2 - Turbine rotor blade coupling device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a turbine rotor blade coupling device for interconnecting adjacent turbine rotor blades of a turbine wheel such as a steam turbine or a gas turbine.

Conventionally, a coupling device for damping vibrations of a turbine rotor blade of a turbine wheel, mainly a long blade which is twisted from the blade root to the tip, has been used, for example, on the trailing edge side of the blade tip of a turbine rotor blade 1, as shown in FIG. 1a and the leading edge side 1b are provided with holes 3 extending substantially perpendicular to the blade longitudinal direction, and holes 3 are provided at the leading edge 2b and trailing edge side (not shown) 2a of the blade tip of the adjacent rotor blade 2 at approximately right angles to the blade longitudinal direction. A hole 4 extending in the rotor blade 1 is provided, and protruding pieces 6 and 7 that protrude horizontally are provided on both sides of the rotor blade cover 5, and one protruding piece 6 is inserted into the hole 3 on the trailing edge side 1a of the rotor blade 1. The protruding piece 7 is fixed by caulking, and the protruding piece 7 is attached to the adjacent rotor blade 2.
There is a device that connects the turbine rotor blades 1 and 2 to each other in series via the rotor blade cover 5 by inserting them into the holes 4 on the leading edge side 2b of the rotor blades and connecting them loosely.

In such a conventionally structured turbine rotor blade coupling device, the results of considering the deformation of the rotor blades 1 and 2 during rotation show that, first, a phenomenon in which the rotor blades untwist (hereinafter referred to as untwist) occurs due to centrifugal force. , Second, there is a difference in the amount of radial elongation due to centrifugal force between the steam inlet end (leading edge) and the steam outlet end (trailing edge) of the rotor blades. These two points are important for the rotor blade coupling device. It is known to have a significant impact.

To explain this in detail, Fig. 2 is a view of the turbine rotor blade viewed from the outer circumferential side, and Fig. 2a shows the turbine when it is stationary.
Figure 2 shows the turbine when it is rotating.

That is, while the turbine rotor blades are rotating, centrifugal force acts on the rotor blades, which are twisted blades, and this centrifugal force generates a moment M that untwists the rotor blades.
By restraining the cover, the untwisting moment is borne by the cover itself.

That is, if the turbine rotor blades 1 and 2 are untwisted as shown in FIG. 2, excessive bending will be applied to the protruding pieces 6 and 7 of the rotor blade cover 5.

Furthermore, due to the centrifugal force acting on the turbine rotor blades, there is a difference in the amount of radial elongation between the leading and trailing edges of the rotor blade tips due to uneven stress, and the blades are bent as shown in Figure 3.
This also causes bending to act on the protrusions 6 and 7 of the rotor blade cover 5.

Therefore, especially since large forces and moments act on the protrusions 6 and 7 of the rotor blade cover 5, there is a high possibility that the protrusions 6 and 7 will break during turbine operation, thereby reducing the safety of the turbine rotor blades. There was a big problem.

SUMMARY OF THE INVENTION An object of the present invention is to provide a turbine rotor blade coupling device that damps vibrations of the rotor blade by restraining untwist acting on the rotor blade, and is safe in terms of strength even when the rotor blade is untwisted.

The gist of the present invention is to provide a plate member at the tip of a turbine rotor blade that protrudes substantially perpendicularly to the longitudinal direction of the rotor blade and to the leading edge side and the trailing edge side of the rotor blade, and to attach a plate member of an adjacent rotor blade to the blade member. In a turbine rotor blade coupling device in which a plurality of coupling members are engaged, one of the coupling members is engaged with the blade tip on the leading edge side of the rotor blade, and the other coupling member is engaged with the blade tip on the leading edge side of the rotor blade. The connecting members are engaged with the blade tips on the trailing edge side of the rotor blades, and the connecting members are disposed such that a portion thereof overlaps with the plate member protruding from the adjacent rotor blade, and a portion of the connecting members The present invention relates to a turbine rotor blade coupling device that engages adjacent rotor blades so that they contact each other during turbine operation, thereby restraining untwisting of the rotor blades and damping vibrations of the rotor blades.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A turbine rotor blade coupling device according to an embodiment of the present invention will be described in detail below with reference to the drawings.

In Fig. 4, the drawing shows a situation where the turbine rotor blade is viewed from the outer circumferential side of the rotor blade when it is rotating and stationary. Eaves projecting approximately perpendicularly to the longitudinal direction of the rotor blade and in opposite directions on the blade trailing edge side (steam outlet side) Ia and the blade leading edge side (steam inlet side) 1b (not shown) at the tip of the blade, respectively. 8a and 8b are provided.

In addition, the adjacent turbine rotor blade 2 is also provided with eaves 9a (not shown) and 9b on the trailing edge side 2a (not shown) and leading edge side 2b of the rotor blade tip, respectively, similarly to the rotor blade 1.

Through holes 10a and 11b are formed in these eaves 8a, 8b and 9a, 9b, respectively, to extend substantially parallel to the longitudinal direction of the rotor blades, that is, to penetrate substantially perpendicularly to the surface of the eaves.

The eaves 8a of the rotor blade 1 and the rotor blade 2 are located close to each other.
The assembly is adjusted so that a minute gap G is maintained between the eaves 9b and the eaves 9b.

Further, oval holes 12a and 12b are provided on the trailing edge side and the leading edge side of the blade tip of the turbine rotor blade 1, respectively, passing through the blade in the longitudinal direction at a substantially right angle to the blade surface.Similarly, the blade tip of the rotor blade 2 Holes 13a t 13b are provided on the trailing edge side and the leading edge side of the blade, which penetrate the blade surface at a substantially right angle in the longitudinal direction of the blade.

Rotor blade connecting pieces 14 and 15 are installed between the blade tips of these adjacent turbine rotor blades 1 and 2.

These rotor blade connecting pieces are formed as a set of connecting pieces attached to the inner peripheral side of the rotor blades of the eaves 8a and 9b of the rotor blade 1.2.

An oblong pin 16 is integrally formed on the end surface of the connecting piece 14, and the pin 16 of the connecting piece 14 is fitted into a through hole 12a provided on the trailing edge side of the tip of the rotor blade 1. Rear pin 1
The end of 6 is loosely caulked and fixed.

A pin 17 is similarly formed on the end face of the connecting piece 15, and the pin 17 is inserted into the through hole 1 provided at the leading edge of the tip of the rotor blade 2.
3b, the ends of the pins 17 are gently caulked and fixed.

Further, cylindrical pins 18 and 19 are integrally formed on the upper surfaces of the connecting pieces 14 and 15, respectively.

The pin 18 of the connecting piece 14 and the pin 19 of the connecting piece 15
are through holes 11 provided in the eaves 9b of the rotor blades 2, respectively.
b and is loosely fitted into a through hole 10a provided in the eaves 8a of the rotor blade 1.

Next, the attachment state of the connecting piece will be explained with reference to FIG.

Figure 5 is a sectional view taken along line XX in Figure 4, showing the eaves 8 of moving blades 1 and 2.
The connecting piece 14 attached to the lower part of a and 9b is shown.

The fitted state between the pin 16 of the connecting piece 14 and the through hole 12a of the moving blade 1, and the fitted state between the pin 18 of the connecting piece 14 and the through hole 11b of the eave 9b of the moving blade 2 are as described above. It is kept loose to allow some movement relative to the through hole.

Furthermore, the upper surface 22 of the connecting piece 14 and the eaves 8a of the rotor blades 1 and 2
The lower surfaces 20a and 21b of t9b are adjusted so that surface contact is maintained when the blade is rotating and stationary.

Next, the structure of the connecting piece will be explained in detail.

FIG. 6 shows the shape of the connecting piece 15 seen from the bottom and top before being assembled.

An oblong pin 17 is integrally formed on the end surface of the connecting piece 15, and is inserted into a through hole 13b provided at the tip of the leading edge of the rotor blade 2 with a slight gap. It is fixed by caulking the part somewhat loosely.

A cylindrical pin 19 is integrally formed at the upper end of the connecting piece 15, and is inserted into a through hole 10a provided in the eaves 8a on the trailing edge side of the rotor blade 1 with a slight gap.

The action of the pin 190 will be described later, but in order to ensure the strength of the base of the pin 19, the through hole 10a of the eaves 8a is
An annular groove 23 is formed as a relief for the corner R of.

In addition, a chamfer 24 is formed on the end face of the connecting piece 15 in order to escape the corner R of the root of the blade tip of the eave 9b of the rotor blade 2, and this device is designed to maintain a good contact state between the rotor blade and the connecting piece. It has been subjected.

Further, on the side surface 25 where the connecting pieces 15 and 14 are adjacent to each other, there is a connecting piece 1.
A protrusion 26 is formed extending toward the lower surface of the coupling piece 15 , and a recess 27 in which the protrusion extending from the coupling piece 14 is accommodated is formed on the lower surface of the coupling piece 15 .

It goes without saying that the connecting piece 14 also has the same shape as the connecting piece 15.

Next, the action and function of the connecting piece during rotation of the rotor blade will be explained.

Figure 7a shows the fourth rotor blade as seen from the outer circumferential side of the rotor blade when the rotor blade is stationary.
Contrary to the figure, this is a view seen from the inner circumferential side of the rotor blade, and Figure 7 shows the following:
FIG. 3 is a view of the rotor blade viewed from the inner peripheral side during rotation.

When rotating and stationary, as mentioned above, the eaves 8a of the moving blades 1 and 2
and 9b are assembled and adjusted so that a gap G is maintained, and at the same time, a gap F is maintained between the protrusions 28 and 26 extending from the two connecting pieces 14 and 15 to the lower surface of each connecting piece. assembled to be

Also, the assembly is performed so that a gap is maintained between the cylindrical pin 18 of the connecting piece 14 and the through hole 11b of the eave 9b, and between the cylindrical pin 19 of the connecting piece 150 and the through hole 10a of the eave 8a. It will be done.

During rotation, an untwist moment M due to centrifugal force acts, and as a result, the gap G between the eaves 8a and 9b tends to increase.

This σ is determined by the gap F between the respective projections 28.26 of the connecting piece 14.15 when at rest, and during rotation the articulating surfaces 31.30 of the projections 28, 26 are in contact with each other and F-0
), forces act on each other to restrict the amount of untwisting to a desired range.

Also, the cylindrical pin 18 of the connecting piece 140 and the through hole 11b of the eaves 9b are connected to the protruding portion 28 of the connecting piece 14.15 during rotation.
26 are assembled and adjusted in advance so that they contact each other at the same time, or maintain a slight gap.

Cylindrical pin 19 of connecting piece 15 and through hole 1 of eaves 8a
The same applies to the relationship with 0a.

In this way, the cylindrical pin 18 of the connecting piece 14, the through hole 11b1 of the eaves 9b, and the cylindrical pin 1 of the connecting piece 15
9 and the through hole 10a of the eaves 8a are connecting pieces 14, 150.
Do the protrusions 28, 26 contact each other at the same time?
Alternatively, after the protrusions 28 and 26 come into contact with each other, the connecting members are elastically deformed so that the protrusions 28 and 26 come into contact with each other.
Together with 8.26, it shares the power to restrain Untwist.

Therefore, in the present invention, the pins 18, 19 and the protrusion 26.
Both pins 18 and 28 have the effect of restraining untwisting, but when there is strength margin in these parts, pins 18.
It is possible to omit either 19 or the projections 26, 28.

From the point of view of ease of processing the shape of the connecting piece, the protrusion 26.28
The part is complicated, and pins 18 and 19 are superior in terms of workability.

Next, considering centrifugal force, as mentioned above, a difference in elongation in the radial direction occurs between the leading edge side and the trailing edge side of the rotor blade due to centrifugal force.

Figure 8a shows a sectional view taken along line XX in Figure 4, and Figure 8a shows a sectional view taken along line YX in Figure 4. Trailing edge side 1a of blade 1 and leading edge side 2 of adjacent rotor blade 2
There is a difference in elongation between blades 1 and 1, and in this case, the trailing edge side 1
The figure schematically shows a situation in which the moving blade a has a larger elongation amount than the leading edge side 2b of the moving blade 2) and is tilted toward the moving blade 1 side.

In Fig. 8a, the elongation of the leading edge side 2b of the rotor blade 2 is
By being smaller than the elongation of the rear edge side 1a, the connecting piece 1
The upper surface of 4 contacts the lower surface of the eaves 9b, and a downward force acts on the connecting piece 14.

In this case, the oblong pin 16 provided on the end surface of the connecting piece 14 and the rotor blade 10 through hole 12a are connected to the pin 1 as described above.
The through hole 12 is designed to allow a certain amount of movement of the connecting piece, and in particular, to allow pivot movement around the pin 16, with respect to vertical movement of the connecting piece.
It is characterized by giving it the shape of a.

Further, as described above, a gap is provided in advance in the relationship between the cylindrical pin 18 on the upper surface of the connecting piece 14 and the through hole 11b of the eave 9b of the rotor blade 2, so that the rotor blade 1, as shown in FIG.
Even if 2 is deformed, unreasonable prying force is not generated around the pin 18 or the through hole 11b of the eaves 9b.

In the case of FIG. 8, the upper surface of the connecting piece 15 remains pressed against the lower surface of the eave 9b of the rotor blade 2 due to centrifugal force, and in this case, the pin 19 on the upper surface of the connecting piece 15 and the rotor blade 1 By providing a gap in advance between the eave 8a and the through hole 10a, unreasonable prying force is not generated around the pin 19 or the through hole 10a of the eave 8a.

In the case of FIG. 8a, the centrifugal force acting on the connecting piece 14 is caused by the contact between the pin 16 and the through hole 12a of the rotor blade 1, and the contact between the upper surface of the connecting piece 14 and the lower surface of the eave 9b of the rotor blade 2. By being supported by the connecting piece 14, part of the centrifugal force acting on the connecting piece 14 is borne by the eaves.

In the case of FIG. 8, the centrifugal force acting on the connecting piece 15 is applied to the contact area between the pin 17 and the through hole 13b of the rotor blade 2 and the connecting piece 15.
It is supported by the contact portion between the upper surface and the lower surface of the eave 9b of the rotor blade 2, and in either case, the structure is such that a part of the centrifugal force acting on the connecting piece can be borne by the eave of the rotor blade.

Next, we will discuss the vibration suppression function, which is the most important function for the turbine rotor blade coupling device.

Explaining with reference to FIG. 7b showing a state in which the connecting pieces 14 and 15 are in contact with each other during turbine operation, the connecting piece 14 is engaged with the blade 1 by inserting and fitting the pin 16 into the through hole 12a of the blade 1, The pin 17 of the connecting piece 15 is connected to the through hole 13b of the wing 2.
The projections 28.2 of these connecting pieces 14.15 are engaged with the wing 2 by being inserted and fitted into the blades 2, and the projections 28.2 of these connecting pieces 14.15 are untwisted.
The blades 1 and 2 are engaged by the blades 5 coming into contact with each other.

Further, the cylindrical pin 18 of the connecting piece 140 and the cylindrical pin 19 of the connecting piece 15 are engaged with the hole 11b of the eaves 9b and the hole 10a of the eaves 8a, respectively, after the protrusions 28 and 25 come into contact with each other. is as described above.

Here, when the blade vibrates in the X direction shown by the arrow in FIG.
A relative slight sliding motion occurs on the connecting surfaces of No. 6, and the friction mainly on this connecting surface exerts a large vibration damping effect.

In addition, in response to vibrations in the X direction, the pin 16 of the connecting piece 14 is loosely fixed to the hole 12a of the blade 1 as described above, and the pin 17 of the connecting piece 15 is also fixed to the hole 13b of the blade 2.
Because the pin 16 is loosely fixed to the hole 12a1 or the pin 1T and the hole 13b, a minute sliding movement occurs, and a minute sliding movement occurs at the contact area between the top surface of the connecting piece and the bottom surface of the eaves. By generating this, it is possible to exhibit a vibration damping effect due to friction.

Next, friction can exert a large vibration damping effect on vibrations in the X direction, that is, the axial direction, and in two directions, that is, torsional vibrations, as in the case of vibrations in the X direction, making it an effective vibration suppressing means for vibrations in all directions. .

Next, a brief explanation will be given of an assembly method for forming the turbine rotor blade coupling device of the present invention.

Figure 9 shows the wings 1, 2 and connecting pieces 14, 15 in the middle of assembly.
It is a figure showing a 0 relationship.

At this stage, the pin 16 of the connecting piece 14 is inserted into the through hole of the wing 1, and the end of the pin 16 remains uncrimped.

On the other hand, the pin 19 of the connecting piece 15 is located in the hole 10a of the eaves 8a.
and is held on the eaves 8a by appropriate means such as a jig.

While the connecting pieces 14 and 15 are held on the wing 1 in this manner, they are moved in the direction shown by the arrow in FIG. 9 and engaged with the wing 2.

That is, the pin 11 of the connecting piece 15 is inserted into the hole 13b of the wing 2.

On the other hand, as shown in FIG. 10 (X-X sectional view in FIG. 9), the connection piece 14 has a relationship between the pin 16 and the hole 12a of the wing, which allows the connection piece 14 to pivot in the vertical direction as described above. With this setting, the pin 18 is inserted into the hole 11b of the eaves 9b of the wing 2 by moving in the direction of arrow A while being pushed down in advance and then pushing it up in the direction of arrow B. .

After the above procedure, the ends of the pin 16 of the connecting piece 14 and the pin 11 of the connecting piece 15 are gently caulked, and the respective wings and the connecting piece are engaged.

As is clear from the above description, according to the present invention, it is possible to restrain the untwist acting on the turbine rotor blades, thereby damping the vibrations of the rotor blades, and to realize a safe turbine rotor blade coupling device without any problems in terms of strength. be able to.

[Brief explanation of the drawing]

Fig. 1 is a schematic explanatory diagram showing a conventional turbine rotor blade coupling device, and Figs. 2 and 3 respectively show the state of the acting force acting on the conventional turbine rotor blade coupling device. Fig. 3a shows the situation when the turbine rotor blade is stationary, and Fig. 3 shows the situation when the turbine rotor blade is rotating. FIG. 4 is a drawing of the blade connecting device, FIG. 4 is an assembly state diagram when the turbine rotor blade is stationary, FIG. 5 is a cross-sectional view in the XX direction of FIG. 4, and FIG. 6 is a connecting piece showing the detailed structure of the connecting piece. A perspective view seen from two directions,
Fig. 7 is a state diagram of the turbine rotor blade connection structure of the present invention viewed from the inner peripheral side of the blade, and Fig. 7a shows the turbine rotor blade when it is stationary, and Fig. 7 shows the turbine rotor blade when it is rotating. Fig. 8 shows the situation during rotation of the turbine rotor blades, Fig. 8a is a sectional view taken along the line X-X in Fig. 4, and Fig.
9 is an assembly state diagram of the turbine rotor blade coupling device of the present invention, and FIG. 10 is a sectional view taken along the line X--
It is a sectional view in the X direction. 1.2... Turbine moving blade, 1a, 2a... Moving blade trailing edge side, 1b, 2b... Moving blade leading edge side, 8at8b... Eaves, 12a, 13b - Blade tip hole, 14.15 - ... Connecting piece, 16, 17... Oval pin, 18.19...
Cylindrical pin, 20a, 20b... Lower surface of eaves, 22.
...Top surface of connecting piece, 23...Annular groove, 24...Chamfer, 25...Side side of connecting piece, 26.28...Protruding part, 2
7... Concavity.

Claims (1)

[Scope of Claims] 1. In a turbine rotor blade coupling device that connects the leading edge side and the rear side of adjacent rotor blade tips, there are surfaces in the blade longitudinal direction on the leading edge side and the trailing edge side of the rotor blade tips, respectively. A hole penetrating the rotor blade is provided at a substantially right angle to the rotor blade, and two connecting members are provided between adjacent rotor blades to engage with the rotor blade, and the end portion of each connecting member is provided at the tip of the rotor blade. A first protrusion that fits into the hole is provided, and the first protrusion of one coupling member is inserted into and engaged with the hole on the leading edge side of the rotor blade, and the first protrusion of the other coupling member is inserted into and engaged with the hole on the leading edge side of the rotor blade. The protrusion is inserted into and engaged with the hole on the trailing edge side of the adjacent rotor blade, and is further radially outer periphery of the hole provided on the leading edge side and the trailing edge side of the rotor blade tip at a angle approximately perpendicular to the longitudinal direction of the rotor blade. and a plate member protruding from the leading edge side and the trailing edge side of the rotor blade, a hole portion is provided in each of the plate members, a second protruding portion is provided on the upper surface of the connecting member, and the connecting member The two connecting members arranged so that the second protrusion of the plate member is inserted into the hole of the plate member and are arranged between the adjacent blades have a part that is connected to the plate of the adjacent rotor blade. A turbine rotor blade connecting device, characterized in that the adjacent rotor blades are connected by arranging the connecting members so as to overlap each other and making contact with each other during turbine operation. 2. The upper surface of the direct coupling member is brought into contact with the lower surface of the plate member during rotation of the turbine, and the plate member allows
The turbine rotor blade coupling device according to claim 1, characterized in that the coupling member bears a part of the centrifugal force acting on the coupling member. 3. A third protrusion extending toward the other side is provided on the side surfaces of the two connecting members that are close to each other, and a third protruding portion extending from the side surface of the connecting member is housed in the lower surface of both the connecting members. Claim 1, characterized in that a third protrusion extending from the side surface of the two connecting members contacts each other to engage adjacent rotor blades during turbine operation. The turbine rotor blade coupling device according to item 1 or 2. 4. A pair of connecting members disposed between the adjacent rotor blades is arranged so that the connecting members are connected to each other at a predetermined inter-blade distance with respect to the movement of the adjacent rotor blades in a direction in which they move away from each other. 4. The turbine rotor blade coupling device according to claim 3, wherein the third protrusions protruding from the side surfaces adjacent to the first and second protrusions are arranged so as to be in contact with each other.