JPS5970803A - Turbine rotor - Google Patents

Abstract

PURPOSE:To prevent cracks at a key seat owing to corrosion and thereby have sure torque transmission by furnishing a coupling member at its both sides with a step each a means to make engagement with a recess formed in the side faces of a wheel. CONSTITUTION:The upper stream wheel 3 is soupled by a coupling member 8, through which the torque is transmitted over to an adjoining wheel. This coupling member 8 is cylindrical, and at its both sides steps 9a, 9b are formed. If the wheel on the steam incoming side is loosened, the torque is transmitted to the shaft through the adjoining wheel. If all wheels are loosened, the torque is transmitted through a wheel bore key 4 in the downmost stream. Crack generation at the key seat owing to stress corrosion can be well prevented according to this arrangement, in which the torque is transmitted through a coupling member 8 consisting of a stepped ring.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to turbine rotors.

[Technical Background of the Invention] In general, long blades with a large average diameter are used in low-pressure rotors of large-scale steam turbines for photoelectric applications, etc., in order to flow a large amount of steam.

In order to solve manufacturing technology and economic problems in such a huge turbine rotor, the wheel into which the blades of each stage are implanted is manufactured separately from the shaft, and then the wheel is heated and then fitted onto the rotor shaft. A so-called yakifu wheel called -S+- is used.

FIG. 1 shows a steam turbine rotor supporting such a roasted wheat wheel, and reference numeral J'3 and C1 in the figure indicate the shaft of the turbine rotor. On this shirt 1-1, a plurality of roasted wheat wheels 3 having blades 2 on the outer periphery are fitted by wheel bore keys 4 along the axial direction of the shaft 1.

Further, a locking key 5 is provided to restrict the movement of the wheel 3 in the axial direction.

Then, the steam energy is converted into i-lux by the blades 2 and then transmitted to the wheel 3, and from this wheel 3 the shaft 1
The transmission of 1 to 1 torque to the wheel is carried out by the frictional force caused by the blood pressure on the shrink fit surface of the wheel 3 and the wheel bore key 4.

That is, in this J: Eel turbine rotor, in a stage where the pressure and temperature are relatively high near the steam inlet side, the wheel 3 with a small heat capacity is heated faster than the shifter I7 [~1] due to the operating condition, and the temperature is increased to the shirt 1. A temperature difference may occur and the wheel 3 may become loose, and in the event that the wheel 3 becomes loose, torque will be transmitted by the wheel bore key 4. The shrink fit surface on the inner surface of wheel 3 is Si 1? The surface pressure with the foot 1 is kept constant, and the stress in the tangential direction of the inner surface is kept uniform.

[Problems with rear technology] However, in the turbine rotor configured in this way, a wheel bore key groove 6 is provided on the inner surface of the wheel 3 in order to fit the wheel bore key 4. Stress is concentrated around key iM 6, and
As shown in the figure, stress corrosion cracking (SCC) 7 has occurred around the wheel bore key h6. In particular, wheel 3 exposed to an atmosphere of about 130 to 150 degrees Celsius
As a result, the wheel 3 becomes a high stress field, and stress corrosion cracking 7 may occur in the wheel bore keyway 6.

[Object of the Invention 1 The present invention has been made in response to such conventional circumstances.
The present invention aims to provide a turbine rotor that can eliminate the risk of stress corrosion cracking occurring in the wheel bore keyway of a wheel, and can also ensure torque transmission between the wheel and the wheel. be.

[Summary of the Invention] Zunawara's present invention provides a mechanism for connecting the wheel that controls the blades to the shirt l-
A plurality of wheels are connected along the axial direction of the turbine rotor 115, and the wheels are connected to each other by a connecting portion 4A, and a turbine rotor 115 is connected to the turbine rotor 115 along the axial direction of the wheel. A turbine rotor C characterized in that a stepped portion is formed to engage with a recess formed in the
be.

[Embodiment of the Invention] Hereinafter, one embodiment of the present invention will be described without showing the details of the present invention in the drawings.

FIG. 3 shows a turbine rotor according to an embodiment of the present invention. In the figure, reference numeral 1 indicates a shirt 1-
It shows. The shirt 1-1 has a wheel 3 having blades 2 planted on its outer circumferential surface along the axial direction -C.
Multiple pieces are fitted. Each wheel 3 located on the upstream side of the turbine rotor is connected to an adjacent wheel 3.
They are connected to each other by a connecting member 8 that transmits torque to. Note that the wheel 3 disposed on the downstream side of the steam inlet of the turbine 1 has a wheel bore key iM 6 formed thereon as in the conventional case, and a wheel bore key 4 is inserted into this wheel bore key groove 6. There is.

FIG. 4 shows an enlarged view of the wheel 3 and the connecting member 8 shown in FIG. Step portions 9a and 9b are formed on each side.

In other words, the stepped portion 9a has a width of W at the upper end in the figure, and the width of the stepped portion gradually becomes O at a position 1800 degrees from the upper end. A stepped portion 9]) having a width W is formed at a position 180° from the upper end of C1, and the width of this stepped portion 9b is gradually reduced until the width reaches 0 at the upper end.

In FIG. 4, the symbol J5'C°3 indicates a wheel.The hub portion 10 formed on both sides of the wheel 3 has a stepped portion 9a formed on the connecting member 8, respectively.
Corresponding to 9b, there is a stepped part 9a, and a fourth part 1 having the opposite shape to 9b.
1a, 11b are formed and the step portions 9a, 9b formed on the connecting portion) TA8 are fitted into the four portions 11a, 11b formed on the wheel 3.

Above J: Turbine rotor-CIJ configured as urchin.

During normal operation of the turbine [1-2], the 1-lux from the wheel 3 is applied to the shaft 1 by the frictional force due to the surface pressure of the wheel 3 during baking.

On the other hand, if the wheel 3 with a smaller heat capacity is heated faster than the wheel 3 (x7) 1~1 and the wheel 3 on the steam inflow side becomes loose, the 1~1~1 lux applied to the loosened wheel 3 is passed through the adjacent wheel 3 to the CS, /V.fu]-1.

For example, when these -1-stream side wheels 3 become loose and torque cannot be transmitted to the shirts 1-1, the wheel bore key 4 installed at the most downstream position locks the wheels 1-1 to the shirts 1-1. The torque is transmitted to Shireff l-1 through the wheel 3 which is attached to the wheel 3.

That is, in the turbine rotor configured in this way,
Since the wheels 3 are connected and torque is transmitted by the connecting member 8 consisting of a stepped ring without using a key, there is no need to form a keyway in the wheel 3 unlike when using a key. Therefore, stress corrosion cracking in the C keyway portion can be prevented.

Further, the connecting member 8 has a simple structure and a high strength, so that it can reliably connect adjacent wheels 3 and reliably transmit one herk.

In the turbine rotor configured in this way, the wheel bore key 6 formed on the inner peripheral surface of the wheel 3 disposed on the steam inflow side can be removed. It is possible to eliminate stress corrosion cracking.

Note that among the wheels 3, the wheel 3a located at the most downstream position
is fixed to the shaft 1 by the wheel bore key 4, but as mentioned above, even if stress concentration occurs, stress corrosion cracking will occur in the wheel 3a in this part d5, which is relatively rare, so the structure is the same as the conventional one. is sufficient.

[Effects of the Invention] As described above, the turbine rotor of the present invention allows adjacent wheels to be connected reliably and easily. Furthermore, since no key is used, the risk of stress corrosion cracking that has conventionally occurred in some parts of the key can be completely eliminated.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view showing a conventional turbine rotor, Fig. 2 is a longitudinal sectional view showing stress corrosion cracking occurring in a part of the rotor, and Fig.
4 is a longitudinal sectional view showing a turbine rotor according to an embodiment of the present invention, and FIG. 4 is an enlarged perspective view showing a wheel and a connecting member shown in FIG. 3. 1.......Shaft 2...Blade 3...Wheel 8...・・・・・・Patent attorney representing connecting components Sasa Suyama −

Claims (1)

[Claims] (1) A turbine rotor in which a plurality of wheels having blades are fitted along the axial direction of the shirt 1 and the wheels are connected to each other by a connecting member -C1
A turbine rotor characterized in that step portions are formed on both side surfaces of the connecting member, each of which engages with a recess formed in a side surface of a wheel.