JP2851493B2 - Hollow blade - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow rotor blade having a core in a hollow portion, which is used for a gas turbine engine for aviation, marine, industrial, and other uses.

[0002]

2. Description of the Related Art Conventionally, a hollow rotor blade having a core in a hollow portion used in aviation, marine and other gas turbines has a cross section shown in FIG. 11 and an enlarged view of an enclosure J shown in FIG. As shown, the contact surface between the skin 1 and the core 3 is 100% joined, and the flutter and resonance are avoided by the wing shape, hollow shape,
This is done by optimizing the core shape.

That is, in FIG. 11, a skin 1 forms an outer peripheral portion of a hollow rotor blade, and a core 3 having a trapezoidal cross section as shown in FIG.
The parts that will come into contact with each other are joined by, for example, diffusion welding, brazing, or other suitable joining means. FIG. 12 schematically shows, for example, the case of welded meat as a welded meat 6 in order to visually clarify the joining.

[0004] The core 3 is made of a honeycomb material, a porous material or the like, other than a member having a corrugated shape as shown in FIG.
A member having a large weight can be used depending on the purpose.

[0005]

The above-mentioned conventional hollow blade has the following problems to be solved.

That is, in a conventional hollow rotor blade having a core in a hollow portion, in order to avoid flutter and resonance, the blade shape,
Optimization of hollow shape, core shape, etc. For this reason, in the conventional hollow rotor blade, if flutter or resonance cannot be avoided after the design is completed or manufactured, it is necessary to reconsider the blade shape, hollow shape, core shape, etc., which requires a great deal of time and effort. There was a problem.

[0007] In order to solve the above-mentioned problems, the present invention, when it is determined that flutter or resonance cannot be avoided after the completion or trial production of a hollow rotor blade, in actual production, the contact member between the skin outer plate and the core is not used. It is an object of the present invention to provide a hollow rotor blade in which only appropriate places are joined and others are kept in contact.

[0008]

According to the present invention, there is provided a hollow rotor blade obtained by inserting a core into a hollow portion formed by a skin forming an outer peripheral portion and joining a contact portion between the skin and the core. The present invention provides a hollow moving blade characterized in that only a suitable number of the contact portions are joined.

[0009]

The present invention is configured as described above and has the following effects.

That is, if only a suitable number of the contact portions between the skin and the core are joined, and the portions that are not partially joined are left, the rigidity is reduced as compared with the case where all the portions are joined by 100%. The natural frequency of the blade is reduced, and no harmful resonance is generated due to a deviation from a resonance point that is matched with the drive side during, for example, trial manufacture. Further, when the hollow rotor blades vibrate on the contact surface where the skin and the core are not partially joined, the skin and the core rub against each other and convert the vibration energy into friction energy. The structural damping of the hollow rotor blade is improved, and flutter and resonance can be avoided more efficiently.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First to fourth embodiments of the present invention will be described with reference to FIGS. The same members as those in the previous embodiment are denoted by the same reference numerals, and description thereof will be omitted unless necessary.

(First Embodiment) A first embodiment will be described with reference to FIGS. FIG. 1 is a schematic exploded perspective view of the hollow blade of the present embodiment, FIG. 2 is a sectional view taken along the line AA of FIG. 1, and FIG. 3 is an enlarged view of an enclosure B of FIG. FIG. 4 is an enlarged view of the enclosure C in FIG. 2 and shows a state where the skin outer plate 1 and the dimple core 3a are in contact with each other and are not joined. .

In FIG. 1, reference numeral 1 denotes a skin outer plate which is joined to each other to form an outer peripheral portion and forms a hollow portion, 2 denotes a dovetail member forming a base portion of a hollow rotor blade, and 3a denotes a trapezoidal projection-shaped hollow dimple. It is a dimple core of a lightweight and high compressive strength material protruding countlessly on its surface. Note that FIG.
For simplicity, the waveform of the dimple core 3a is schematically shown.

Surface of dimple core 3a and skin skin 1
3 and FIG. 4, but the portion of the enclosure B in FIG. 2 is in contact with the dimple core 3a and the skin by solid phase diffusion bonding, liquid phase diffusion bonding, brazing, etc., as shown in FIG. The outer plate 1 is joined. On the other hand, in FIG.
Are not joined as shown in FIG. By the way, conventionally, as shown in FIG. 3, all the contact points are joined.

The molten metal 6 in FIG. 3 is a molten metal indicating that the skin outer plate 1 and the dimple core 3a have been joined, and it does not matter whether it is so-called solid metal, brazed meat, or the like.

The enclosures B and C shown in FIG. 2 are representatively picked up. However, in actuality, the location of the enclosure B, that is, the ratio of the joined locations is high, and the location of the enclosure C remains in contact. Is low, for example, because it exists in a thinned state.

As described above, if the contact surface between the dimple core 3a and the skin outer plate 1 is not joined at an appropriate position, even if one torsional rigidity is taken, for example, the opposing skin outer plates 1 are interposed via the dimple core 3a. When the dimple cores 3a and the skin outer plates 1 are joined to each other, the gaps should be restrained, but the gaps are not joined because the joints are not joined. Becomes larger (compared to a state where all are joined). That is, the flexibility increases and the rigidity decreases. This also applies to bending stiffness. In particular, in the case of bending, the effect is exerted on the non-joined portion by maintaining the degree of freedom in separating the compression-side skin outer plate 1 and the dimple core 3a in addition to the displacement. Appears sensitively.

Since the rigidity is one of the factors of the frequency, the lower the rigidity, the lower the natural frequency, for example. Accordingly, the skin outer plate 1 and the dimple core 3a are joined and tested at all contact portions as in the conventional case, and the test is performed by matching the required number of revolutions with the conditions on the drive source side, such as gas temperature and gas speed. Against the resonance
With the configuration as in this embodiment, the resonance point is shifted downward, that is, a so-called mismatch condition of the resonance condition occurs, and strong resonance can be avoided. In addition, the dimple core 3a that is not bonded due to vibration
The friction between the contact portion of the skin 1 and the skin 1 causes mutual friction, so that part of the vibration energy is converted to friction energy, and the vibration is attenuated accordingly.

(Second Embodiment) Next, a second embodiment will be described with reference to FIGS.

FIGS. 5A and 5B are partial views of this embodiment. FIG. 5A is a perspective view in vertical section (however, the middle in the span direction is omitted), and FIG. 5B is a sectional view taken along the line DD in FIG. 6 is an enlarged view of the box E in FIG.

In both figures, reference numeral 3b denotes a honeycomb core which enters the space formed by the skin outer plate 1.

As shown in FIG. 6, since the honeycomb core 3b is used so that the hole axis of the honeycomb is perpendicular to the skin outer plate 1, the end face of the honeycomb core 3b in the hole axis direction is uniformly formed on the skin outer plate 1. However, these contact surfaces are joined at an appropriate number of places, and the other portions remain in contact.

This embodiment also provides the same functions and effects as the first embodiment.

(Third Embodiment) Next, a third embodiment will be described with reference to FIG.

FIG. 7 is an exploded perspective view of the present embodiment. Reference numeral 3c denotes a corrugated sheet core which enters a space formed by the skin outer plate 1. The corrugated sheet core 3c has a trapezoidal waveform when viewed in the longitudinal direction, and has a top surface in contact with the skin outer panel 1. As in the first embodiment, an appropriate number of all the contact points are joined, and the other points remain in contact. This embodiment also has the same function and effect as the first embodiment.

(Fourth Embodiment) Next, a fourth embodiment will be described with reference to FIGS.

FIG. 8 is a schematic exploded perspective view of this embodiment, and FIG.
Is a sectional view taken along the line FF in FIG. 8, and FIG. 10 is an enlarged view of the box G in FIG.

In these figures, a trapezoidal projection 1a is provided on the inner side of the skin outer plate 1, that is, on the surface in contact with the dimple core 3a, facing the dimple of the dimple core 3a.

Accordingly, the skin skin 1 and the dimple core 3
FIG. 10 shows a state in which a is in contact with a. However, this shape itself is also in the conventional example, and is not special in this embodiment. Incidentally, in this shape, the stress line S flows in the shape as shown by the broken line in the figure, and even if the contact between the dimple core 3a and the skin outer plate 1, specifically, the projection 1a is joined, the stress line S
However, it does not reach the joining, and is adopted because of its advantages such as high fatigue strength.

Also in this embodiment, not all the contact surfaces between the projection 1a on the skin outer plate 1 side and the dimple core 3a shown in FIG. 10 but an appropriate number of portions are joined, and the other portions remain in contact. It is said.

This embodiment has the same operation and effect as the first embodiment.

In each of the first to fourth embodiments, it is free to apply a coating for preventing abrasion to the non-joined contact surface among the contact surfaces on the core side and the skin side. If a material that can be used for preventing welding is used, the purpose of selectively non-joining only the surface concerned can be achieved at the same time. Further, in order to increase the frictional energy consumption at the contact surface, that is, to increase the vibration damping, the contact surface may be subjected to a process for increasing the surface roughness.

The above embodiments have been described in connection with an example in which the individual frequency is lowered after the trial production. However, these embodiments are not based on the trial production. For example, a constant span and a constant If the apparent width of is required, and if a general-purpose material is used for the core and the skin, if it is judged that the possibility of entering the resonance region is high due to high rigidity when joining all contact surfaces of the core and the skin, Alternatively, if it is predicted that the lowering of the rigidity is stochastically expected to be able to escape from the dangerous vibration area, only a suitable number of contact surfaces, as in the embodiment, should be used as far as the strength and bending allow. Of course, it is free to adopt a configuration joined from the beginning.

As described above, according to the first to fourth embodiments, only a suitable number of the contact surfaces between the dimple core 3a, the honeycomb core 3b, the corrugated core 3c and each skin outer plate 1 are joined. There is an advantage that the rigidity of the hollow moving blade is reduced, the natural frequency is lowered, and the hollow moving blade can escape from the resonance region and the flutter region when used as the hollow moving blade.

Therefore, even if a defect such as flutter or resonance is found by, for example, trial manufacture, it is not necessary to change the wing shape, hollow shape, core shape, etc. as in the prior art, and
There are many advantages in that a large amount of time required for these reviews is not required.

[0036]

The present invention has the following effects because it is configured as described above.

That is, according to the present invention, only a suitable number of the contact portions of the hollow rotor blade obtained by inserting a core into the hollow inside of the skin and joining the contact portion between the skin and the core are joined. However, since the other parts are not joined, the rigidity is reduced, so that flutter or resonance can be easily avoided without reviewing the wing shape, hollow shape, core shape and the like. This saves a great deal of time and effort.

[Brief description of the drawings]

FIG. 1 is a schematic exploded perspective view of a first embodiment of the present invention,

FIG. 2 is a sectional view taken along the line AA of FIG. 1;

FIG. 3 is an enlarged view of an enclosure B in FIG. 2;

FIG. 4 is an enlarged view of a box C in FIG. 2;

5 (a) is a longitudinal sectional view of a second embodiment of the present invention, FIG.
(B) is a sectional view taken along the line DD of (a),

FIG. 6 is an enlarged view of an enclosure E in FIG. 5 (b),

FIG. 7 is a schematic exploded perspective view of a third embodiment of the present invention,

FIG. 8 is a schematic exploded perspective view of a fourth embodiment of the present invention,

9 is a cross-sectional view taken along the line FF of FIG. 8;

FIG. 10 is an enlarged view of a box G in FIG. 9;

FIG. 11 is a cross-sectional view of a conventional example.

FIG. 12 is an enlarged view of an enclosure J in FIG. 11;

[Explanation of symbols]

 Reference Signs List 1 skin outer plate 1a protrusion 2 dovetail member 3a dimple core 3b honeycomb core 3c corrugated plate core

Claims (1)

(57) [Claims] 1. A hollow rotor blade obtained by inserting a core into a hollow portion formed by a skin forming an outer peripheral portion and joining a contact portion between the skin and the core, joining only an appropriate number of the contact portions. A hollow rotor blade characterized by being formed.