JPS599541A - Device for testing rotation of turbine disk with automatic centering device - Google Patents

Abstract

PURPOSE:To make it possible to rotate a disk at a super high speed, by coupling the conical protruded part of a shaft with a cone shaped tapered hole which is provided in a turbine disk, and holding the disk by the surface pressure of the tapered hole. CONSTITUTION:A cone shaped tapered hole 13 is formed at an inner hole 14 of a turbine disk 1. A conical protruded part 12, which is coupled with said tapered hole 13, is provided at a shaft 2. A bush 3 is provided at the other part of the shaft 2. The bush is tightened by a nut 5 through a coned disk spring 4 and a spherical washer 6. Thus the disk 1 is held by the surface pressure of the tapered hole 13. Even though the disk 1 is rotated and the inner hole 14 becomes large due to a centrifugal force, the protruded part 12 is pushed into the hole 13 by the elasticity of the coned disk spring 4, and the disk 1 is held to the shaft 2. Therefore vibration due to unbalance is not yielded, the disk 1 can be rotated at a high speed of 5,000-20,000 rotations, and residual stress can be added.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of a turbine disk rotation test device, and relates to a turbine disk rotation test device that automatically adjusts the alignment between the disk and the shaft to increase the rotation speed. .

A turbin blade is attached to the tip of the turbine disk, and the turbine disk is used at high speed rotation.

Therefore, in actual use, the weight of the disk φ body is large, and the rotating diameter (tip of the blade) is also large, so vibrations due to unbalance of the rotating body, strength against centrifugal force, etc. Tests will be conducted to confirm reliability.

In addition, in order to strengthen the strength of the disk against centrifugal force, the disk is rotated at high speed using a rotation testing device to create residual stress inside the disk material, and this residual stress is offset by compressive stress generated by centrifugal force during operation. In this way, the internal stress applied to the disk is reduced.

This principle will be explained in more detail.

As shown in FIG. 1, when a circular disk having an inner hole diameter d is rotated at full speed, the inner hole diameter d increases due to centrifugal force.

This phenomenon is caused by centrifugal force, just like when a shaft is press-fitted into the inner hole d to increase the inner hole diameter di.
It appears because compressive force is applied in the radial direction of the disc.

If this stress distribution is shown at one point on the disk, it will be like curve A, with the stress distribution being maximum at the part closest to the inner hole and decreasing closer to the outer periphery of the disk.

This compressive stress can be left as a residual stress inside the material of the disk.This residual stress resists the compressive stress that attempts to increase the inner hole diameter d while the disk rotates, and reduces the inner hole diameter di. In the direction #I'@, the compressive stress and the residual stress cancel each other out, resulting in a state in which there is virtually no compressive stress in the disc, and the strength against centrifugal force can be strengthened.

This relationship is shown in FIG. In the figure, the 0 point is the point where the inner hole is, as shown in FIG.
ll+ is a compressive stress axis with the 0 point being 0 compressive stress. Curve A is the response generated by the rotation of the disc. Curve B is the residual stress, and this internal stress is at the boundary of y#lt,
During the rotation of the disk, they act in opposite directions, and stress as shown by curve C is applied to the disk.

The above-mentioned residual stress cannot be applied to the material within the elastic limit of the material, but is applied at the yield point of the material.

Therefore, in order to apply residual stress to the disc, it is necessary to rotate the disc at an extremely high speed and apply compressive stress to the yield point of the disc material.

A conventional turbine disk rotation testing device has a structure shown in FIGS. 3 and 4.

That is, in the conventional rotation testing apparatus shown in FIG.
The turbine disk 1 was fixed to the shaft 2 by tightening a nut 5 via a disc spring 4.

In this rotation test device, when the turbine disk 1 is rotated at high speed, the centrifugal force causes the turbine disk 1 to rotate at high speed.
As the inner hole becomes larger, the fixed state with the shaft 2 becomes loose, and the N8 between the turbine disk 1 and the shaft 2 is no longer maintained, resulting in imbalance and vibration.

Furthermore, it is difficult to shrink-fit the shaft 2 to the turbine disk 1 concentrically, and it is difficult to achieve N8 with high precision. As a result, when the turbine disk was rotated at high speed, it became unbalanced and caused vibrations.

For these reasons, in this device, the disk outer diameter is 1
Taking the case of 500 m as an example, there was a drawback that it was not possible to rotate at a speed of 3000 RPM or more, and it was not possible to apply residual stress to the turbine disk.

Next, the conventional rotation testing apparatus shown in FIG.
The turbine disk 1 was fixed with bolts 7 and nuts 8.

With this configuration, the turbine disk 1
In response to the deformation caused by the centrifugal force of the cone-shaped portion 2at-deformation, N8 of the turbine disk l and the shaft 2 is held.

However, the length of the shaft becomes large, and especially in the case of a large turbine disk, an increase in the total weight of the rotating body becomes a problem.

In other words, in high-speed rotation, it supports a large rotating weight,
When rotating at high speed, there are problems with the strength of the support part and driving power against vibrations caused by unbalance, and there is a limit to the speed of high-speed rotation. Further, since a large centrifugal force is generated near the connection between the cone-shaped portion 2a and the turbine disk l, there is a problem in the strength of the cone-shaped portion 2a, which limits the maximum possible rotational speed.

For example, the outer diameter of the turbine disk is 15001111
% If the pitch diameter of the bolt 7 is 1000 m, the maximum rotational speed will be 5000 RPM.

For this reason, the turbine disk had the disadvantage that sufficient residual stress could not be applied to it.

In addition, it may be necessary to test the turbine disk by heating or cooling it, and in such cases, the cone-shaped part
Since it covers the upper half of the turbine disk, it has the disadvantage that efficient and uniform heating or cooling cannot be achieved.

The present invention aims to solve the above-mentioned conventional drawbacks and provide a turbine disk rotation testing device that can rotate at ultra high speeds.

That is, in the present invention, all bolt-shaped taper holes are formed on both sides of the inner hole of the turbine disk, and one end of the shaft is provided with a conical protrusion that fits into the tapered holes formed on both sides of the inner hole. The shaft is inserted into the inner hole of the turbine disk, and a conically shaped bushing is fitted onto the other side of the shaft, and between this bushing and the conical protrusion provided on the shaft, the turbine is heated by the surface pressure of the tapered hole. The disk is held between the disks, and even if the turbine disk rotates at high speed and the inner hole becomes large, the turbine disk is held between the surfaces of the tapered hole and is completely maintained in agreement with the shaft.

Examples of the present invention will be described below. In the following description, the outline of this embodiment will first be explained using FIG. 6.

In the figure, on both sides of the inner hole 14 of the turbine disk 1,
A mortar-shaped taper hole 13 is formed.

On the other hand, one end of the shaft 2 is provided with a conical protrusion 12 that fits into the tapered hole 13 formed on both sides of the inner hole 140. While fitting the tapered hole 13, the shaft 2
A bushing 3 formed into a conical shape is fully inserted into the other side of the bushing 3, and the turbine disk 1 is completely held between the bushing 3 and the protrusion 2 by the surface pressure of the tapered hole 13. This is applied by tightening the nut 5 through the spherical washer 6.

With this configuration, the turbine disk 1
rotates and the inner hole 14 becomes larger, the conical protrusion 12 and bushing 3 are pushed into the tapered hole 13 by the elastic force of the countersunk spring 14, and are clamped and fixed to the metal shaft 2 of the turbine disk 1. , the concentricity between the two is maintained, vibrations due to unbalance are eliminated, the turbine disk 1 is rotated at high speed, and residual stress is applied.

The details will be explained in more detail below. FIG. 5 shows an outline of the rotation test apparatus.

In the figure, a turbine disk 1 is fixed to a shaft 2, which is connected to a drive turbine 9. This drive turbine 9 is fixed on a frame 10 that wraps around the outside of the turbine disk 1 and is fixed on a foundation 11 .

FIG. 6 shows the fixing of the turbine disk 1 and shaft 2 more clearly.

In the figure, an inner hole 14 is bored in the center of the turbine disk 1 . A pot-shaped taper hole 13 is formed on both sides of the inner hole 14 . A conical protrusion 12 that fits into the tapered hole 13 is provided at one end of the shaft 2 . 3 is a bush, which is shaped into a conical shape so as to fit into the tapered hole 13. 4 is a disc spring, and 6 is a spherical washer. The tightening force of the nut 5 is evenly transmitted to the disc spring via the spherical washer 6, and the elastic force of the disc spring 40 causes (
9) Bush 3 is pressed with even force.

In other words, the turbine disk 1 is held between the protruding portion 12 that fits into the tapered hole 13 and the bush 3 by the elastic force of the disc spring 4, and is fixed to the shaft 2 inserted into the inner hole 14. Further, in the inner hole 14 portion, the diameter of the shaft 2 is smaller than that of the inner hole, and an annular gap is provided.

The operation of this embodiment configured as described above will be explained.

First, the turbine disk 1 is rotated by the drive turbine 9 via the shaft 2 . This rotation speed is
Depending on the purpose of the rotation test, ・5000 to 20000 RPM
This is done while controlling the rotation within the range of .

When the turbine disk 1 is rotated at high speed, the inner diameter of the inner hole 14 increases due to centrifugal force. In such a case,
In the bolt-shaped taper hole 13 formed on both sides of the inner hole 14, a protrusion 12 provided at one end of the shaft 2 and a bush 3 are connected.
While the mating surface is sliding, due to the elastic force of the disc spring 40,
It is pushed into the tapered hole 13 (10).

In this way, the protrusion 12 and the bushing 3 are pushed into the taper hole 13 according to the width of the inner hole 14, fixing the turbine disk 1 to the shaft 2, and at the same time keeping the cores of the turbine disk 1 and shaft 2 together. Align concentrically.

Conversely, even if the rotational speed becomes slower and the inner diameter of the inner hole 14 becomes smaller, the bushing 3 and the protruding part 12 will continue to maintain their tapered shape while sliding on the fitting surfaces between the tapered hole 13, the bushing 3, and the protruding part 12. It is pushed out from the hole 13.

In this way, in accordance with the change in the inner diameter of the inner hole 14, the turbine disk 1 is maintained in a fixed state, and at the same time, alignment is performed fully automatically.

As detailed above, according to the rotating device of the present invention, a mortar-shaped taper hole is formed on both sides of the inner hole, and a protrusion provided on the shaft and a bush are fitted into the taper holes, so that a turbine disk can be mounted. Because it is clamped, it is possible to automatically align the turbine disk at the same time (11) when the turbine disk is fixed to the shaft, even though the inner diameter of the inner hole changes due to centrifugal force, and even if the turbine disk rotates at high speed, it will not be unbalanced. No vibrations occur.

Therefore, it is possible to apply a compressive load to the turbine disk up to its yield point and impart residual stress, thereby increasing the strength of the turbine disk against centrifugal force generated by high-speed rotation.

In this way, the problem of vibration in rotating equipment is solved, and the rotation test of the turbine disk can be carried out reliably at a rotation speed that matches the purpose of the rotation test, improving the reliability of the rotation test and improving the strength of the turbine disk. It has great effects, such as strengthening the turbine disk and improving the reliability of the turbine disk itself.

Furthermore, it is easier to assemble and disassemble compared to conventional methods of fixing turbine disks, such as shrink fitting or bolt tightening.
In addition, heating and cooling of the turbine disk is easy, which not only improves p1 operability, but also allows the entire device itself to be made smaller.
As a result, less driving power is required, and there is a great effect in terms of economy.

(12)

[Brief explanation of drawings]

Figures 1 and 2 are diagrams shown in the ninth column explaining the relationship between residual stress and the state in which compressive stress moves in the disk due to centrifugal force when the disk is rotated at high speed. 4 is a conventional example, FIG. 3 is a partially assembled cross-sectional view of the turbine disk fixed to the shaft by shrink fitting, FIG. 4 is a partially assembled sectional view of the turbine disk fixed to the shaft by bolting, and FIGS. 5 and 6 are examples of the present invention. Figure 5 is a schematic diagram of the entire system, and Figure 6 is a vertical cross-sectional view of the fixed parts of the turbine disk and shaft. 1... Turbine disk, 2... Shaft s 4
+... Disc spring, 5... Nut, 6... Spherical washer, 1
2...Protrusion part, 13...Tapered hole, 14...Inner hole. Agent Patent attorney Masami Akimoto (13) Kaya 2nd year, 3rd country, 4th year, 5th year, 6th year

Claims (1)

[Claims] 1. A cone-shaped tapered hole is formed on both sides of the inner hole of the turbine disk, and a conical protrusion is provided at one end of the shaft to fit into the tapered hole formed in the turbine disk.
The shaft is inserted into the inner hole of the turbine disk to fit the conical protrusion and the tapered hole, and a bushing formed in a conical shape is fitted into the other side of the shaft, and the bushing and the conical shaped bushing provided on the shaft are fitted. The turbine disk is held between the protrusion and the protrusion by the surface pressure of the Taber hole.1-
Turbine disk rotation test equipment with self-aligning features.