JPS5977003A - Turbine rotor - Google Patents

Abstract

PURPOSE:To make it possible to simply inspect stress corrosion cracks in a wheel in a device in which a plurality of wheels provided with a plurality of blades are fitted onto a shaft and are interconnected by means of engaging members, by enabling the engaging members to be removed radially to the wheels. CONSTITUTION:A plurality of wheels 3 planted with blades 2 are fitted onto a shaft 1 and are therefore arranged axially of the shaft 1, and those of wheels 3 which are positioned upstream of a turbine rotor are interconnected with wheel radial keys 8, respectively. In this arrangement, both side surfaces of the hub 9 of each wheel 3 are respectively formed with wheel radial key grooves 10 (not shown) and ring-like stress relieving grooves 11 contacting with both upper and lower edges of the key grooves 10. Meanwhile, each of the above-mentioned keys 8 is composed of a driving member 13, key members 14a, 14b arranged at both sides of the driving member 13 and holding parts 12 formed at the lower ends of the key members 14a, 14b are inserted in the stress relieving groove 11. With this arrangement, each key 8 may be simply removed from each key groove by cutting a caulking part 16 to take out the driving member 13.

Description

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

[Technical Background of the Invention] Generally, in a low-pressure rotor of a large steam turbine for power generation, blades having a large average diameter and a long length are used in order to flow a large amount of steam.

In order to solve manufacturing technology and economic issues with such huge turbine rotors, the wheel into which the blades of each stage are implanted is manufactured separately from the shaft, and the wheel is then heated before being fitted onto the rotor shaft. A so-called shrink-fit wheel is used.

FIG. 1 shows a steam turbine rotor having such a shrink-fitted wheel, and in the figure, reference numeral 1 designates a shirt 1 of the turbine rotor. A plurality of shrink-fit wheels 3 having blades 2 on the outer periphery are fitted onto the shaft 1 by wheel bore keys 4 along the axial direction of the shaft 1.
There is C.

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

In the turbine constructed in this way, the energy of the steam is converted into 1 to 1 kg by the blades 2 and then transmitted to the wheel 3, and the torque is transmitted from the wheel 3 to the shaft 1 by the wheel. This is done by the friction force due to the blood pressure of the shrink-fitting surface 3 and the wheel bore key 4.

In other words, in such a turbine rotor, in a stage where the pressure and temperature are relatively high near the steam inlet side, the wheel 3, which has a small heat capacity, is heated faster than the shaft 1 due to the operating conditions, and the temperature difference between the wheel 3 and the shaft 1 is increased. As a result, 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 on the inner surface of the wheel 3 keeps the blood pressure with the shaft 1 constant and maintains uniform stress in the tangential direction of the inner surface.

[Problems with the background art] However, the turbine rotor C configured in this way
A wheel bore key groove 6 is provided on the inner surface of the wheel 3 to fit a wheel bore key 4, and stress is concentrated around this wheel bore key groove 6, as shown in FIG. , stress corrosion cracking 7 (SCC) may occur around the wheel bore keyway 6. Especially about 13
When the wheel 3 is exposed to an atmosphere of 0 to 150° C., 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] The present invention has been made in order to cope with such conventional circumstances C1
An object of the present invention is to provide a turbine rotor in which stress corrosion cracking occurring in a keyway formed in a wheel as necessary can be easily inspected during the service life of the turbine rotor, and torque transmission between a wheel and a shaft can be reliably performed. It is something that covers.

[Summary of the Invention] In other words, the present invention provides a wheel having blades for a shirt 1-
In a turbine rotor, a plurality of wheels are fitted along the axial direction, a locking groove is formed in the side surface of the wheel, and the wheels are interconnected by a locking member inserted into the locking groove, The turbine rotor is characterized in that the locking member is removable in the radial direction of the wheel.

[Embodiments of the Invention] Details of the present invention will be described below with reference to embodiments shown in the drawings.

FIG. 3 shows a turbine rotor according to an embodiment of the present invention, and in the figure, reference numeral 1 indicates the shaft of the turbine rotor. A plurality of wheels 3 each having blades 2 implanted on the outer circumferential surface of the shaft 1 are fitted along the axial direction. The wheels 3 located on the upstream side of the turbine rotor are connected to each other by a connecting member, for example, a wheel radial key 8, which transmits torque to the adjacent wheels 3.

The wheel 3a disposed on the downstream side of the steam inlet of the turbine rotor has a wheel bore key groove 6 formed therein as in the conventional case, and the wheel bore key 4 is inserted into the wheel bore key groove 6.

FIG. 4 shows an enlarged view of the wheel 3 shown in FIG. 3, and in the figure, reference numeral 3 indicates the wheel.

Wheel radial key grooves 10, which are locking grooves, are formed in the radial direction at an angle of 180° on both sides of the hub portion 9 of the wheel 3, and this wheel radial key f
M 10 (7) An annular stress relaxation groove 11 is formed in contact with the lower end a and the upper end. A rectangular wheel radial key 8, which is a locking member, is inserted into the wheel radial key groove 10 of the wheel 3, and the holding portion 12, which is a convex portion formed at one end of the wheel radial key 8, is inserted into the stress relaxation groove 11. The wheel radial key 8 is inserted into the interior of the wheel radial key 8 to prevent the wheel radial key 8 from coming off due to centrifugal force due to the same rotation of the turbine rotor.

Figure 5 shows details of the wheel radial key 8.
This wheel radial key 8 is composed of a driving member 13 disposed in the center and key members 14a, 14b disposed on both sides of the driving member 13, and the lower end of the key parts ttJJ14a, 14b. A holding part 12 is formed in each of the parts to be inserted into the stress relaxation groove 11.

That is, the wheel radial key 8'c configured in this manner has the key member 14 in the wheel radial keyway 10.
After inserting a and 14b, the key member 1/l of this set
The drive 815 and 13 are inserted between a and 14b by IJ engagement (the wheel radial key 8 is fixed in the wheel radial keyway 10. Then, the key member 14a,
By caulking the protrusion 15 formed on the outer circumferential side of the fJ member 14b in the direction of the driving member 13, the fJ projecting member 13 is completely identified with the key member 14a114b.

However, in the wheel radial key 8 configured as described above, during maintenance and inspection during the service life of the turbine rotor, the caulked portion 16 is cut, the driven member 13 is removed, and the wheel radial key 8 is attached to the wheel radial key 8. By easily pulling it out from the keyway 10, it is possible to visually inspect the wheel radial keyway 10 for the presence or absence of cracks such as stress corrosion cracks. After the C inspection, the wheel radial key 8 can be inserted into the wheel radial keyway 10 from the radial direction of the wheel 3 by the method already described.

In the turbine rotor configured as described above, torque from the wheel 3 is transmitted to the shaft 1 by the frictional force due to the surface pressure of the shrink fit curve of the wheel 3 during normal operation of the turbine rotor.

On the other hand, if the wheel 3 with a smaller heat capacity is heated faster than the shaft 1 and the wheel 3 on the steam inflow side becomes loose, the torque applied to the loosened wheel 3 is transmitted to the shaft 1 via the adjacent wheel 3. For example, when all of these upstream wheels 3 become loose and torque cannot be transmitted to the shaft 1, the torque is transmitted via the wheel 3 disposed at the most downstream position and locked to the shaft 1 by the wheel bore key 4. Torque is transmitted to the shaft 1.

6 to 10 respectively show wheel radial keys of other embodiments of the turbine rotor of the present invention. In the wheel radial key shown in FIG. 6, key members 14a and 14b shown in FIG. The upper end of the wheel radial key is connected by a connecting member 17, and the key members 14a and 14b are inserted into the wheel radial keyway 10 to take advantage of the deformation of the connecting member 17. The connecting member 17 is cut and the key members 14a, 14b are pulled out from the wheel radial keyway 10.

In the wheel radial key shown in FIG.
The lower end portions of the key members 18a and 18b are connected to the connecting member 19, and a holding portion 20 is formed in the central portion of the key members 18a and 18b.

In such a wheel radial key, the wheel radial key is inserted into the wheel radial key groove 10 by deformation of the material 19 before connection in the same manner as the wheel radial key shown in FIG. can be taken out from the wheel radial keyway 10.

The wheel radial key shown in Figure 8 has a screw 21 on the outer periphery.
In this case, a threaded hole with a semicircular cross section is used as the wheel radial keyway 10, and by screwing the threaded member 22 into this threaded hole, the wheel and the wheel are connected. A combination is performed.

The wheel radial key shown in FIG. 9 is composed of a key member 23 and a driving member 24 formed on the side surface of the key. After this, the projection 25 formed on the upper end of the key member 23 is inserted into the driving member 24.
Wheel radial keyway 1 by caulking towards
Fixed to 0.

FIG. 10 shows the wheel radial key 8 shown in FIG. 5 (instead of caulking the driving member 13, the driving member 13 is fixed to the key member 1da, 1/lb with bolts 25.

[Effects of the Invention] As described above, according to the turbine rotor of the present invention, the locking member that connects the wheels can be easily attached to and removed from the locking groove, so that it cannot be locked during periodic inspections, etc. By removing the member, cracks such as stress corrosion cracks that occur in the wheel radial keyway can be easily inspected.

[Brief explanation of the drawing]

Figure 1 is a vertical cross-sectional view showing a conventional turbine, Figure 2 is a vertical cross-sectional view showing stress corrosion cracking that occurs in a part of the
The figure is a longitudinal sectional view showing a turbine [1-1] of an embodiment of the present invention, FIG. 4 is a perspective view showing an enlarged view of the wheel in FIG. 3,
Figure 5 shows an enlarged view of the wheel radial key in Figure 4.
The front view and FIGS. 6 to 10 are explanatory diagrams showing a wheel radial key of a turbine 0-1 in other embodiments of the present invention, respectively. 1.......Shaft 2...Blade 3...Wheel 8... ...Wheel radial key 10
・・・・・・・・・Wheel radial keyway 13
...... Drive-in members 14a, 14b
... Kichi Parts Representative Patent Attorney Satoshi Suyama - Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] (1) A plurality of wheels having blades are fitted along the axial direction of the shaft, a locking groove is formed on the side surface of the wheel, and the wheels are mutually connected by a locking member inserted into the locking groove. In the connected turbine rotor C, the locking member has the above-mentioned, E/L=17)? Mka. ,
4□, 60. . A turbine rotor featuring a