JP2000356112A - Steam turbine and gas turbine integral type shaft structure using clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten a shaft length between bearings and to prevent the occurrence of resonance of natural vibration. SOLUTION: A shaft 1 on the generator side and a shaft 11 on the steam turbine side are coupled together through a clutch 33 for a single shaft. The shaft 1 on the generator side is integral structure with the clutch 33 for a single shaft, a groove 2 for feeding oil is formed at the inner part of a shaft, an oil feed pipe from an external pipe is eliminated, and an overall length is shortened. Further, also in the shaft 11 on the steam turbine side, a bearing 37, a thrust bearing 13, and a coupling 14 are brought into contact with each other, an independent thrust collar is eliminated, and since a groove 12 for feeding oil is also formed in the coupling 14, a shaft length is shortened. This constitution, since a shaft length between the bearings 37 and 38 on both sides of the coupling 33 for a single shaft is shortened, reduces the generation of vibration and avoids vibration instability due to resonance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shaft structure integrated with a steam turbine and a gas turbine using a clutch. The shaft length of the shaft system via the clutch is shortened to form a compact shaft system to avoid shaft vibration. It is a structure.

[0002]

2. Description of the Related Art A combined cycle power generation plant in which a steam turbine and a gas turbine are uniaxially connected via a clutch has been developed. In such a single-shaft coupling plant, it is necessary to disengage the clutch between the gas turbine and the steam turbine. Allows the gas turbine to operate independently, starts the gas turbine, accelerates the steam turbine at an appropriate speed increase, automatically activates the clutch when the steam turbine reaches the generator speed, The turbine and the gas turbine are connected uniaxially, and a combined cycle operation is performed.

FIG. 2 is a conceptual diagram of the single-shaft combined cycle power plant described above. In the figure, a steam turbine 30 and a gas turbine 31 are connected to a generator 32.
And a single-shaft clutch 33. 34
Is a heat recovery steam generator, 35 is a chimney, and 36 is a condenser. In the combined cycle power plant having such a configuration, the exhaust gas after burning by the gas turbine 31 and driving the gas turbine is guided to the exhaust heat recovery boiler 34, and heats the water from the condenser 36 to exhaust heat. And released to the atmosphere from the chimney. On the other hand, the water heated by the exhaust gas is converted into steam and guided to the steam turbine 30. The steam turbine 30 is driven, and the low-temperature steam worked by expansion is returned to the condenser 36 to be condensed.

In the single-shaft combined cycle power plant having the above-described configuration, first, the single-shaft clutch 33 is set in a disengaged state. The uniaxial clutch 33 has a structure in which the casings 33a and 33b can be fitted or disengaged by moving the slider 39 left and right as described later. At the time of startup, the generator 32 is operated by the gas turbine 31, the temperature of the exhaust gas is raised, and the exhaust heat recovery boiler 34 is sufficiently operated to operate until the high-temperature steam can be generated. After that, the exhaust heat recovery boiler 34 rises, the steam is sufficiently supplied to the steam turbine 30, and the rotation speed of the steam turbine 30 reaches the rotation speed of the generator 32.
The slider 39 moves automatically to the fitted state,
The generator 32 is operated by the steam turbine 30 and the gas turbine 31 by connecting the left and right clutches 33a and 33b.

FIG. 3 is a flowchart for explaining the operation of the uniaxial clutch 33 described above. This type of clutch has already been commercialized as a Synchro-Self-Shifting clutch, and is a known technique. Therefore, only the main points of the engagement and disengagement will be described. In the drawings, (a) is a sectional view showing a state at the time of detachment, and (b) is a sectional view showing a state at the time of fitting.
In (a), the slider 39 is movable left and right, and the gear 42 and the casing 33 are provided on the side of the casing 33b.
The gears 45 are provided on the side of a. On the other hand, a gear 45 is provided inside the casing 33a, and a gear 44 is provided inside the end of the casing 33b. (A)
In the figure, a generator side shaft 40 and a steam turbine side shaft 41
In this state, the gears 42, 43 at both ends of the slider 39 do not mesh with the casings 33b, 33a, and are in a disengaged state.
The casings 33a and 33b rotate freely without being restricted by each other.

In FIG. 3B, when the generator-side shaft 40 and the steam turbine-side shaft 41 are synchronized, the slider 39
Moves to the left side in the figure, and the gears 42 and 43 of the slider 39 are connected to the gear 44 of the casing 33b and the casing 3 respectively.
3a and the casings 33a and 33b.
Is in the fitted state. Therefore, the generator-side shaft 40 and the steam turbine-side shaft 41 can rotate integrally in synchronization.

FIG. 4 is a view showing a shaft connected to the one-shaft clutch 33 shown in FIG. In the drawing, a generator-side shaft 40 is mounted on the casing 33b side of the single-shaft clutch 33, and a steam turbine-side shaft 41 is mounted on the casing 33a side by shrink fitting. The generator-side shaft 40 is provided with a plurality of oil supply pipes 52, and supplies oil to the bearing 38 and the single-shaft clutch 33. And bearing 37
The generator side shaft 40 is provided with a thrust collar 51. On the other hand, the steam turbine side shaft 41 is supported by a bearing 37, and a thrust collar 50 is provided between the steam turbine side shaft 41 and the uniaxial clutch 33 to receive the thrust.

The shaft connected by the single shaft clutch 33 as described above is provided with an oil supply pipe 52 for supplying oil to the thrust collars 50 and 51 and the single shaft clutch 33, and the shaft is shrink-fitted. Therefore, it is necessary to lengthen the structure of the fitting portion, and these factors increase the axial length L. If the shaft length L is long, the characteristic value of the bending vibration between the bearings 37 and 38 exists at a rotation speed lower than the rated rotation speed, and when this mode resonates at a low rotation speed, unstable shaft vibration is generated. Also, when such shaft vibration occurs, the generator-side shaft 4
0, the reaction force of the bearing pressure of the bearing 38 is small and misalignment during operation (increase of oil film, increase of oil film temperature, error of base surface, etc.)
, Sufficient surface pressure is not secured, and shaft vibration is not stable.

[0009]

As described above, in a shaft structure integrally formed with a steam turbine and a gas turbine using a conventional single-shaft clutch, the shafts of bearings 37, 38 supporting both sides to which the single-shaft clutch 33 is coupled. The length L between the bearings becomes longer due to the presence of the thrust collar 50 and the oil supply pipe 52, or the shrink-fitting structure of the shaft, and the like. Vibration occurs. The occurrence of such unstable vibration is a problem in the safe operation of the plant, and the shaft vibration must be avoided.

Accordingly, in the present invention, in a shaft structure integrated with a steam turbine and a gas turbine using a single-shaft clutch,
The problem is to propose a shaft structure that avoids shaft vibration resonance and prevents unstable shaft vibration as a shaft structure that minimizes the length between bearings on both sides of a single-shaft clutch as much as possible. It was done.

[0011]

The present invention provides the following means (1) to (3) to solve the above-mentioned problems.

(1) In a steam turbine and a gas turbine integrated shaft structure, a clutch is interposed between a steam turbine side shaft and a generator side shaft and the generator and the gas turbine are connected. The generator-side shaft connected to the shaft end of the generator is a shaft integral with the clutch side, and the thrust bearing of the steam turbine-side shaft is between a radial bearing side surface and a shaft coupling side surface fixed to the clutch side. A steam turbine and gas turbine integrated shaft structure using a clutch, which is in contact with both sides.

(2) One end of each of the generator-side shaft and the steam turbine-side shaft serves as an oil supply source for a radial bearing.
A shaft structure integrated with a steam turbine and a gas turbine using the clutch according to (1), wherein a plurality of oil supply holes whose other ends communicate with the inside of the clutch are provided.

(3) The radial bearing on the steam turbine side can be set at an offset lower than the thrust bearing on the generator side by sliding with the side surface of the thrust bearing. A steam turbine and gas turbine integrated shaft structure using the clutch according to claim 1.

In the steam turbine and gas turbine integrated shaft structure using the clutch of the present invention, the shaft on the generator side is integrally formed with the clutch. Conventionally, the shrink-fitting structure of the shaft requires a long shrink-fitting portion structure. However, this can be shortened. On the steam turbine side shaft, the thrust bearing is in contact with the radial bearing side surface and the coupling side surface and slides to receive the thrust force. Can be eliminated, and the axial length can be shortened accordingly.

As described above, since the shaft on the generator side and the shaft on the steam turbine side can be made shorter than in the prior art, the shaft length between the radial bearings on both sides of the clutch becomes shorter, thereby bending the shaft between the bearings. Vibration can be reduced, and resonance at the time of low-speed rotation of an eigenvalue due to vibration can be avoided, and vibration instability can be suppressed.

In (2) of the present invention, the oil supply hole is provided in the shaft on both the generator side shaft and the steam turbine side shaft, and the oil required by the clutch is supplied to the radial bearing. It is guided to the clutch from the oil supply source through the shaft. Conventionally, since the oil supply pipe to the clutch was connected from the outside, the connection portion was required, and the shaft length was increased by that length. However, the oil supply pipe became unnecessary in (2) of the present invention. Can be shortened.

In (3) of the present invention, since the side surface of the radial bearing and the side surface of the thrust bearing are in contact with each other and do not affect the structure of the thrust bearing even if they slide with each other, the radial bearing on the generator side can be used. In order to adjust the load between the radial bearings on the steam turbine side, the offset at the time of setting the radial bearing on the steam turbine side shaft lower than the radial bearing on the generator side shaft can be easily performed.

[0019]

Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a sectional view of a steam turbine and gas turbine integrated shaft structure using a clutch according to an embodiment of the present invention. In the figure, the single-shaft clutch 33 has the same configuration as that of the conventional example, and therefore detailed description is omitted, and the conventional reference numeral is quoted and described. The lower side shows a state in which the slider 39 moves and the gears 42 and 43 of the slider 39 are engaged with the gear 44 of the casing 33b and the gear 45 of the casing 33a, respectively.

In FIG. 1, a generator-side shaft 1 integrated with a casing 33b is attached to one of the single-shaft clutches 33 (right side in the figure). The integral generator-side shaft 1 is provided with a plurality of oil supply holes 2 whose one end communicates with the casing 33b of the single-shaft clutch 33 in the peripheral axial direction. Is configured to communicate with a groove 38a around the bearing 38 and supply oil from the oil supply system of the bearing 38 to the casing 33b side of the single-shaft clutch 33.

The conventional casing 33b side was separately provided with an oil supply pipe on the shaft, so that a space for this equipment was required. However, in the present invention, the oil supply pipe was removed, and instead, The oil is supplied from the bearing 38 to the casing 3 of the single-shaft clutch 33 through the oil supply hole 2 formed in the shaft 1.
3b, so that there is no oil supply pipe.
The shaft length can be shortened.

Further, since the generator-side shaft 1 has an integral structure with the casing 33b of the single-shaft clutch 33, the structure of the shrink fitting portion is not required as compared with the conventional shrink fitting structure.
The shaft length can be shortened accordingly. Thus, the generator-side shaft 1 eliminates the conventional oil supply pipe, and instead, the shaft 1
The oil supply hole 2 is provided in the inside, and the shaft 1 is connected to the single shaft clutch 3
3, the shaft length can be made shorter than before because the shrink-fitting system is an integral shaft structure.

A flange 1 is provided at the opposite end of the generator-side shaft 1.
a is formed, and a flange 61 is joined to the flange 1a and connected by bolts / nuts 62 to form a coupling. The flange 61 has a shaft end 6 on the generator 32 side.
0 is inserted by shrink-fitting, and since this shrink-fitting portion is outside the generator side of the bearing 38, the distance L between the bearings 37, 38 on both sides of the uniaxial clutch 33 (see FIG. 2). It is not a factor of lengthening.

The material of the generator-side shaft 1 integrally formed with the single-shaft clutch 33 is made of 3.5NiCrMoV steel, and is processed at a reduced reburn temperature to increase the strength. Therefore, the diameter of the shaft can be made smaller than before,
This also makes it possible to reduce the size of the generator-side shaft 1 as a whole.

The other side (left side in the figure) of the single shaft clutch 33 is provided with a steam turbine side shaft 11 connected to the casing 33a via the coupling 14. The steam turbine side shaft 11 is supported by a bearing 37, and a thrust bearing 13 is provided. Further, a plurality of oil supply holes 12 are provided in the shaft 11 around the axial direction.

One end of the oil supply hole 12 communicates with the inside of the casing 33 a of the uniaxial clutch 33, and the other end of the oil supply hole 12 has a bearing 37.
And the oil supply system of the bearing 37 supplies oil to the casing 33a side of the single-shaft clutch 33.

The thrust bearing 13 is provided on the side of the bearing 37.
One side is sliding closely. Further, the other side surface of the thrust bearing 13 is in contact with the coupling 14 and slides similarly to receive a thrust force. That is, the bearing 37 of the steam turbine side shaft 11 of the present invention, the thrust bearing 1
3 and the coupling 14 are in close contact with each other, which eliminates the need for a separately provided thrust collar 50 as in the prior art.
Since both side surfaces of 3 are in close contact with the bearing 37 and the coupling 14, respectively, the shaft length can be shortened accordingly. Such a structure is provided on both sides of the bearing 37 as shown.

In order to adjust the surface pressure imbalance between bearings due to the load difference between the bearing 38 of the generator shaft 1 and the bearing 37 of the steam turbine shaft 11 during assembly, The bearing surface of the bearing 37 is set at 0.
The offset can be given by lowering by about 1 to 0.2 mm. This is a structure in which the bearing 37 and the thrust bearing 13 are in contact with each other on the side surface and receive a thrust force. Since the side surface can slide, such a setting is possible.

As described above, according to the embodiment of the present invention, the coupling on the generator side of the single-shaft clutch 33 is formed as the generator-side shaft 1 having a structure integral with the casing 33b of the single-shaft clutch 33. In addition to eliminating the conventional shrink-fitting structure on the clutch, the oil supply hole 2 is provided in the shaft 1 so that oil is supplied to the uniaxial clutch 33 from the bearing 38, thereby eliminating the conventional oil supply pipe. Structure. As a result, the generator-side shaft 1 can have a shorter structure than the conventional one.

Further, in the steam turbine side shaft 11, the bearing 37 is joined to the thrust bearing 13 and the coupling 14, so that the conventional thrust collar 50 is eliminated, and the oil supply hole 12 is similarly formed. Oil is supplied from the bearing 37 to the single-shaft clutch 33 side by being bored in the coupling 14 of the shaft 11, whereby the steam turbine side shaft 1
1 can also be a structure with a shorter axial length than before.

As described above, both the generator-side shaft 1 and the steam turbine-side shaft 11 have shorter shaft lengths than in the prior art, so that the shaft length between the bearings 37 and 38 on both sides of the single shaft clutch 33 is smaller than in the prior art. Can be shorter. Thus, the bearing 3
The bending of the shaft between the shafts 7 and 38 is reduced, and the resonance phenomenon in the eigen mode of the bending vibration of the shaft, which has occurred at a low rotation speed, can be avoided, and the unstable phenomenon of the shaft vibration can be suppressed. In terms of specific numerical values, the amplitude of the vibration can be within 15/100 mm, and within this value, the unstable phenomenon of vibration does not occur.

[0032]

The steam turbine and gas turbine integrated shaft structure using the clutch according to (1) of the present invention provides (1) a clutch interposed between a steam turbine side shaft and a generator side shaft;
In the steam turbine and gas turbine integrated shaft structure configured by connecting the generator and the gas turbine, the generator-side shaft connected to the shaft end of the generator is a shaft integrated with the clutch side. The thrust bearing of the steam turbine side shaft is in contact with both sides between a radial bearing side surface and a shaft coupling side surface fixed to the clutch side. With such a configuration, the generator-side shaft has an integral structure with the clutch, and the shrink-fitting structure of the shaft conventionally required a long shrink-fitting portion structure, but this can be shortened. In addition, on the steam turbine side shaft, the thrust bearing is in contact with the radial bearing side surface and the coupling side surface, and slides to receive the thrust force. Can be eliminated,
The shaft length can be shortened by that much. As described above, the generator-side shaft and the steam turbine-side shaft can be made shorter than before, so that the shaft length between the radial bearings on both sides of the clutch is shortened, thereby reducing the bending vibration of the shaft between the bearings. To avoid resonance at low speed rotation of the eigenvalue due to vibration,
Vibration instability can be suppressed.

In (2) of the present invention, the oil supply hole is provided in the shaft on both the generator side shaft and the steam turbine side shaft, and the oil required by the clutch is supplied to the radial bearing. It is guided to the clutch from the oil supply source through the shaft. Conventionally, since the oil supply pipe to the clutch was connected from the outside, the connection portion was required, and the shaft length was increased by that length. However, the oil supply pipe became unnecessary in (2) of the present invention. Can be shortened.

In (3) of the present invention, the side surface of the radial bearing and the side surface of the thrust bearing are in contact with each other, and even if they slide with each other, they do not affect the structure of the thrust bearing. In order to adjust the load between the radial bearings on the steam turbine side, the offset at the time of setting the radial bearing on the steam turbine side shaft lower than the radial bearing on the generator side shaft can be easily performed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a steam turbine and gas turbine integrated shaft structure using a clutch according to an embodiment of the present invention.

FIG. 2 is a general configuration diagram of a single-shaft combined cycle power plant.

FIG. 3 shows the operation of the uniaxial clutch shown in FIG. 2,
(A) is an explanatory view showing a clutch disengagement state, (b) is an explanatory view showing a state of clutch engagement.

FIG. 4 is a sectional view of an integral shaft structure using a conventional clutch.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Generator side shaft 2, 12 Oil supply groove 11 Steam turbine side shaft 13 Thrust bearing 14 Coupling 30 Steam turbine 31 Gas turbine 32 Generator 33 Single shaft clutch 37, 38 Bearing 39 Slider 42, 43, 44, 45 Gear

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tatsuharu Takahashi 2-1-1 Shinhama, Arai-machi, Takasago-shi, Hyogo F-term in Takasago Works, Mitsubishi Heavy Industries, Ltd. 3G081 BA02 BA11 BB00 BC07 BD00 DA30

Claims (3)

[Claims] 1. A steam turbine and a gas turbine integrated shaft structure, wherein a clutch is interposed between a steam turbine side shaft and a generator side shaft and the generator and the gas turbine are connected to each other, The generator-side shaft connected to the shaft end of the machine is a shaft integrated with the clutch side, and the thrust bearing of the steam turbine-side shaft is provided between a radial bearing side surface and a shaft coupling side surface fixed to the clutch side. A steam turbine and gas turbine integrated shaft structure using a clutch, which is in contact with both sides. 2. A plurality of oil supply holes, one end of which is connected to an oil supply source of a radial bearing, and the other end of which is connected to the inside of the clutch, are provided in the generator-side shaft and the steam turbine-side shaft, respectively. A steam turbine and gas turbine integrated shaft structure using the clutch according to claim 1. 3. The radial bearing on the steam turbine side,
The steam turbine using a clutch according to claim 1 or 2, wherein an offset disposed lower than the thrust bearing on the generator side can be set by sliding with the side surface of the thrust bearing. Turbine integrated shaft structure.