JPH072962Y2 - Impeller of axial turbo machine - Google Patents

Description

TECHNICAL FIELD The present invention relates to an impeller of an axial flow turbomachine such as an axial flow turbine or an axial flow blower.

2. Description of the Related Art In a conventional impeller of an axial flow turbomachine, for example, as shown in FIG. 8, a Christmas tree shape (or a sawtooth shape, a dovetail shape, an inverted T shape, etc.) is formed on the outer circumference of a single disk 01. (See also FIG. 9) and an assembly impeller in which a plurality of mounting grooves 02 are drilled, and the roots 04 of the respective moving blades 03 that are substantially complementary to the mounting grooves are implanted in each mounting groove 02. As shown, there is an integral impeller in which a plurality of moving blades 05 are integrally formed with the disk 06 by casting or the like.

Problems to be Solved by the Invention In the assembled impeller described above, the moving blade 03 is caused by mutual frictional action at the contact surface between the blade root 04 of the moving blade 03 and the corresponding mounting groove 02 of the disk 01. A damping effect is generated to damp the vibration of the moving blade 03, and the vibration stress of the moving blade 03 becomes smaller than in the case of the integral impeller, and the safety factor is improved, but there is a problem that the manufacturing cost is high.

In the case of the integrated impeller, contrary to the case of the assembled impeller, the manufacturing is simple, but the rotor blade
Since the damping at the root of the moving blade 05 is small with respect to the exciting force acting on 05, excessive vibration stress is generated at the root of the moving blade 05, and cracks easily occur at this portion. is there.

It is an object of the present invention to provide an impeller for an axial flow turbomachine, which improves the drawbacks of the integral impeller as described above and combines the advantages of the integral impeller and the advantages of the assembled impeller. .

Means for Solving the Problems As a concrete means for solving the above problems, the present invention provides an impeller in which a plurality of moving blades are integrally formed on the outer circumference of a disk. , And a narrow width having an opposing surface that penetrates through both side surfaces of the disk and that has outer peripheral portions that are parallel to each other or that face each other with an inclination that gradually expands toward the disk center, in the intermediate portion of the roots of the moving blades that are adjacent to each other. A slit is formed in the shape of the neck and in the shape of a circular hole in which the inner peripheral side portion is substantially circular or raindrop-shaped, and an insertion material having a shape that fills substantially the entire space is inserted into the slit without welding. There is.

Operation With the configuration of the present invention, the portion where the maximum vibration stress acting on the moving blade moves from the root portion of the moving blade (conventional) to the circular hole side of the slit, and the insertion material and the slit Due to the frictional action generated between the circular hole and the narrow neck, the action of damping the vibration of the moving blade occurs.

Embodiments FIGS. 1 to 5 show a first embodiment of the present invention.

In the first embodiment, a plurality of moving blades 2 are integrally formed on the outer circumference of the disk 1, and both side surfaces of the disk 1 are formed on the outer circumference of the disk 1 and at the root intermediate portions of the moving blades 2 adjacent to each other. A slit 3 is provided which extends slightly obliquely over 1a and 1b, that is, in a direction slightly inclined with respect to the central axis (not shown) of the disk 1 (see FIG. 2).

The outer peripheral portions of the slits 3 are opposite surfaces 4 that are parallel to each other.
It is in the form of a narrow neck 4 with a, 4b and also each slit 3
The inner peripheral side portion of is shaped like a circular hole 5 having a substantially circular shape.

As shown in FIG. 4, each slit 3 is composed of a plate-shaped portion 7 and a cylindrical portion 8 that are substantially complementary to the inner surface shape of the slit 3, that is, fill substantially the entire space of the slit 3. The insert material 6 is inserted with a minute gap.

With such a configuration, the maximum vibration stress generated by the exciting force acting on the moving blade 2 is generated in the portion indicated by the line AA in FIG. 1 in the conventional impeller without the slit 3. However, as shown by the line BB in FIG. 1, it moves to the circular hole portion 5 where the stress concentration is relatively small, and at this portion, the friction between the inner surface of the slit 3 and the outer surface of the insert member 6 occurs. Since the damping effect of damping the vibration is generated by the action, the vibration of the moving blade 2 is not excessive and the maximum vibration stress can be suppressed to a small value.

When the impeller is stationary, the insert 6 at the upper part of the impeller stops while the lower surface of the cylindrical portion 8 is in contact with the inner surface of the circular hole portion 5 of the slit 3, but when the impeller rotates. Due to the minute gap between the inner surface of the slit 3 and the outer surface of the insert member 6, all insert members 6 are pushed toward the outside of the disk 1 by the centrifugal force, as shown in FIG. The bottom part floats above the bottom part of the circular hole part 5 of the slit 3 and comes into frictional contact with the part of the slit 3 near the outer peripheral part of the disk 1 to produce the damping effect as described above.

6 and 7 show a second embodiment of the present invention.

In the second embodiment, both facing surfaces 4a ', 4b' of the narrow neck portion 4'in the slit 3'are formed with an inclination so as to gradually expand from the opening portion toward the circular hole portion 5 '. At the same time, the continuous portion of the narrow neck portion 4'and the circular hole portion 5'is formed into a gentle curved surface, and in accordance with this, the cross-sectional shape of the insert 6'is almost complementary to the slit 3 ', It is formed like raindrops.

With the configuration as in the second embodiment, the outer surface of the insert 6'and the slit 3'when the insert 6'is pushed outward by the centrifugal force as described above during the rotation of the impeller. The frictional force with the inner surface of the blade can be increased in proportion to the rotational speed of the impeller, and the slit 3'when assembled
There is an advantage that the insertion member 6'can be easily inserted.

Modifications In the above-described embodiments, the slits 3 and 3'are formed on the disc 1.
Although the inserts 6 and 6'are inserted after forming the above, the preformed insert can be filled with the cast gurney when the impeller is cast. In this case, in order to avoid the metal welding of the insert material and the disk material, that is, to make them non-welded, the insert material is preferably made of, for example, ceramic.

Further, the cross-sectional shape of the slit and the insert material is not limited to only those of the above-mentioned embodiment, for example, a gourd shape,
Other shapes can be used.

Further, the circular hole portions 5, 5 ', etc. of the slits 3, 3'of the above-mentioned embodiment do not need to be perfect circles.

As is apparent from the above, according to the present invention, it is easy to manufacture and has a damping action against the vibration of the rotor blade.
It is possible to provide an impeller of an axial flow turbomachine with high safety.

[Brief description of drawings]

1 is a partial front view of the first embodiment of the present invention, FIG. 2 is a sectional view taken along line II-II of FIG. 1, and FIG. 3 is taken along line III-III of FIG. Sectional view, FIG. 4 is a perspective view of the insert in the first embodiment, FIG. 5 is a sectional view taken along the line V-V in FIG. 2, and FIG. 6 is a view of the second embodiment of the present invention. FIG. 7 is a perspective view of the insertion member, FIG. 7 is a sectional view of a portion similar to FIG. 5 in the second embodiment, FIG. 8 is a partial front view showing an example of a conventional impeller, and FIG. It is a partial front view which shows another example of the impeller. 1 ... Disk, 2 ... Moving blade, 3, 3 '... Slit, 4,
4 '... narrow neck, 5,5' ... circular hole, 6,6 '... inserted material, 7 ... plate, 8 ... cylindrical.

Claims (1)

[Scope of utility model registration request] 1. An impeller in which a plurality of moving blades are integrally formed on the outer circumference of a disk, the outer circumference of the disk and the intermediate portion of the roots of the moving blades adjacent to each other are penetrated over both side surfaces of the disk. , And in the form of a narrow neck having outer surfaces that are parallel to each other or that have opposing surfaces that face each other with a slope that gradually expands toward the center of the disc, and that of the inner diameter that is substantially circular or raindrop-shaped. An impeller of an axial flow turbomachine, wherein a shaped slit is provided, and an insert having a shape that fills substantially the entire space of the slit is inserted in a non-welded state.