JPH048908A - Thrust bearing device for rotating equipment - Google Patents

Abstract

PURPOSE:To eliminate influence of a rotor material on bearing characteristics by forming thrust collars reciprocally facing in the axial direction in one body and providing a thrust bearing main body sandwiching a slide surface at a specific position in the axial direction on the opposite side of a coupling surface of a shaft coupling hub to connect a rotor shaft. CONSTITUTION:Thrust collars 24a, 24b are formed in one body on the opposite side of a coupling surface of shaft coupling hubs 19a, 19b connecting rotor shafts 8a, 8b to each other and a thrust bearing device 6a is held on a bearing stand 13 through a bearing outer ring 14. The thrust collars 24a, 24b are arranged as sandwiched between thrust bearing pads 10a, 10b provided on this thrust bearing device 6a. Consequently, it is possible to decrease the manday for processing and the number of component parts and reduce cost without shaving the thrust collars 24a, 24b out of the rotor shafts 8a, 8b and accordingly, possible to eliminate influence of rotor materials on bearing characteristics.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a thrust bearing device for rotating equipment, and in particular, the bearing characteristics are not affected by the material of the rotor shaft, and the manufacturing cost and the The present invention relates to a thrust bearing device for rotating equipment that can reduce maintenance costs.

(Prior Art) A large number of large rotating equipment such as steam turbines are installed in thermal or nuclear power plants and chemical plants. For example, in a power generation plant, a steam turbine power generation device as shown in FIG. 2 is provided. This steam turbine power generation device is constructed by axially connecting a high-pressure turbine 1, an intermediate-pressure turbine 2, two low-pressure turbines 3a and 3b, and a generator (not shown). Both ends of the rotor shaft of the high-pressure turbine 1, the rotor shaft of the intermediate-pressure turbine 2, and the rotor shaft of each low-pressure turbine 3a, 3b are supported by journal bearings 4a to 4h, respectively, while the rotor shafts adjacent in the axial direction are each They are bolted to each other by shaft couplings 58 to 5c.

Further, a rotor shaft of a generator (not shown) is coupled to the rotor shaft on the output side of the low-pressure turbine 3b via a shaft coupling 5d.

On the other hand, when the rotor shaft, which is integrally connected by the shaft joints 5a to 5d, is rotated by high pressure steam, a thrust force is generated in the axial direction due to the pressure difference before and after each turbine stage. The rotor shaft of the intermediate pressure turbine 2 is equipped with a thrust bearing device 6 for preventing displacement of the rotor shaft in the axial direction in response to this thrust force. Note that the thrust bearing device 6 may be disposed on the rotor shaft of the high-pressure turbine 1 in some cases.

FIG. 3 is a sectional view showing a structural example of a conventional thrust bearing device for a steam turbine. This thrust bearing device 6 includes a thrust collar 9 that is cut out from a rotor shaft 8 and formed integrally, and a pair of thrust bearings that are arranged so as to sandwich the rain shelter surface of the thrust collar 9 from both sides in the axial direction. pad 10
a, 10b and these thrust bearing pads 10a, 1
The thrust bearing body 11 is supported via a thrust bearing body 11 with a U-shaped cross section that holds the thrust bearing body 11 and restrains displacement of the thrust collar 9 in the axial direction, and a curved seat 12 formed on the outer periphery of the thrust bearing body 11. , and a bearing outer ring 14 that transmits the thrust force received by the thrust bearing body 11 to the bearing stand 13. Furthermore, an oil drain 15 is provided on the inner circumferential surface of the thrust bearing body 11 facing the thrust collar 9 to prevent leakage of the lubricating oil filled therein. On the circumferential surface, there is also a seal ring 16a for preventing leakage of lubricating oil.
16b is provided.

In recent steam turbine power generation equipment, the steam conditions have been increased to high temperature and high pressure in order to improve thermal efficiency and economical operation, and the main steam pressure is usually 246 kg.
/caf, the main steam and reheat steam temperatures are typically set at about 538°C or 566°C.

Main steam supplied from a thermal power boiler or nuclear reactor enters the turbine from one side of the high-pressure turbine 1, expands the high-pressure turbine stage to perform work, and then returns to the boiler reheater (not shown) to be reheated. The reheated steam enters the turbine from the center of the intermediate-pressure turbine 2, expands the intermediate-pressure turbine stage and applies rotational force to each rotor shaft, and then passes through the steam connecting pipe 7 to the low-pressure turbine. Flow to turbines 3a and 3b.

The rotational force generated by each of the turbines 1, 2, 3a and 3b is sequentially transmitted to the rotor shaft of a generator (not shown) via shaft couplings 5a to 5d, and the generator converts the rotational force into electric power.

Furthermore, when the rotor shaft of each turbine is rotated by steam, a thrust force is generated in the axial direction due to the pressure difference before and after each turbine stage.
Since the rotor shaft 8 is held by the thrust bearing device 6 disposed on the rotor shaft 8, displacement of the rotor shaft 8 in the axial direction is prevented.

However, in recent years, there has been an increasing social demand to further improve the thermal efficiency of steam turbine power generation equipment and to improve its operating economy.
In order to meet this demand, methods are being adopted in which the main steam temperature or the reheat steam temperature is set to a high temperature exceeding 566°C. A plant that generates power using this method is a so-called USC (υ11 "2SIIper Cr1tical
: Ultra-high-pressure, high-temperature) power plants, for example, power plants that operate under steam conditions in which the main steam temperature and the reheat steam temperature are both 593° C. are already in operation.

By the way, when a rotor shaft that comes into contact with steam at a temperature of 566° C. or higher is formed from conventional Cr-Mo-V@, high-temperature creep strength is insufficient, so it is generally formed from high-Cr steel. However, high Cr steel has poor bearing properties due to its low thermal conductivity, and when fine foreign matter gets mixed in with the lubricating oil into the bearing journal, it causes local overheating, resulting in propagation. , there is a high possibility that a defect called so-called galling will occur in the journal portion.

Conventionally, in order to prevent the occurrence of galling, a material having a higher thermal conductivity than the material of the rotor shaft 8 (high CI #l), for example, Cr-M, as illustrated in FIG. 4, has been used.

A structure is also adopted in which a journal sleeve 17 formed of V-steel is integrally fixed to the rotor shaft 8 by shrink fitting with a press-fit key 18. A shaft coupling hub 1 is attached to the end of the rotor shaft 8.
9 are integrally fixed via a key 20.

Further, as shown in Fig. 5, a structure is adopted in which a welded metal 21 having a thermal conductivity close to that of Cr-Mo-V steel is formed on the outer peripheral surface of the rotor shaft 8 made of high Cr steel to form a journal part. There is.

By forming the journal part with a material with low thermal conductivity in this way, overheating in the journal part is eliminated.
The occurrence of galling can be effectively prevented.

The above measures are for journal bearings 4a to 4h, but the main steam temperature and reheat steam temperature are both 566°C.
If it exceeds this, similar measures will be required for the sliding surface of the thrust collar of the thrust bearing device. Therefore, as shown in FIG. 4, a structure in which a thrust collar 9a made of Cr-Mo-V steel is shrink-fitted to a rotor shaft 8 made of high Cr steel via a key 22, or a structure in which a thrust collar 9a made of high Cr steel is used as shown in FIG. A structure is also adopted in which metal layers 23a and 23b having thermal conductivity as low as that of Cr-Mo-V steel are welded to both pressure-receiving surfaces of the thrust collar 9b integrally formed on the rotor shaft 8 made of Cr-Mo-V steel. .

(Problem to be Solved by the Invention) However, according to the configuration of the thrust bearing device shown in FIG.
In order to ensure that the thrust force transmitted from the rotor shaft 8 is transmitted to the thrust bearing body via the thrust collar 9a,
It is necessary to provide a fixing key 22 between the rotor shaft 8 and the thrust collar 9a.

Therefore, in addition to the preparation of the slither roller 9a, keyway machining and the like are also required, which increases the number of parts constituting the device, resulting in an increase in the number of man-hours for manufacturing and maintenance of the bearing device. In addition, the rotor shaft 8 and thrust collar 9a were prepared separately.
Since it has a structure in which the thrust collar is essentially cut out integrally from the rotor shaft, the strength is weaker and the permissible value of the thrust force is smaller than that of a structure in which the thrust collar is essentially cut out integrally from the rotor shaft.

On the other hand, as illustrated in Figures 5 and 6, it is currently not certain that complete welding between high Cr steel and low Cr steel such as Cr-MQ-V steel, which have different chemical compositions and linear expansion coefficients, is possible. has not yet been obtained, and in order to put it into practical use over a long period of time,
There are still problems with low reliability.

Note that either the main steam temperature or the reheat steam temperature is 538
If the standard steam conditions are around ℃, the materials for the rotor shaft of the high-pressure turbine, which comes into contact with the main steam, and the rotor shaft of the intermediate-pressure turbine, which comes into contact with the reheated steam, are separated. is made of conventional Cr-Mo-V steel, and a thrust collar can be integrally formed on the rotor shaft by machining, making it possible to effectively prevent galling.

However, as in the steam turbine of the USC power plant, both the main steam temperature and the reheat steam temperature are 566.
If the temperature exceeds .degree. C., both rotor shafts are formed of high Cr steel, which is not an effective solution.

The present invention has been made to solve the above problems, and provides a thrust bearing for rotating equipment in which the bearing characteristics are not affected by the material of the rotor shaft, and the manufacturing cost and maintenance cost can be reduced. The purpose is to provide equipment.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention connects the rotor shafts of a plurality of rotating devices in the axial direction using a shaft coupling, and solves the problem that occurs when the rotor shafts of a plurality of rotating devices are rotated together. receives thrust force,
In a thrust bearing device for rotating equipment that maintains the axial position of each rotor shaft in a predetermined position, a pair of shaft coupling hubs that connect the rotor shafts of adjacent rotating equipment, and a shaft coupling hub on the opposite side of the joint surface of each shaft coupling hub, respectively. A pair of thrust collars are arranged and integrally formed on each shaft joint hub so as to face each other in the axial direction, and a thrust bearing body that sandwiches the sliding surfaces of both thrust collars at a fixed position from the axial direction. Features (Function) In the thrust bearing device for rotating equipment having the above configuration, since the thrust collar is integrally formed on each shaft joint hub, the thrust collar is separated from the rotor shaft as in the conventional case. Compared to the case where the bearing is formed by machining, the number of processing steps and the number of component parts can be reduced, and the manufacturing cost and maintenance cost of the thrust bearing device can be significantly reduced.

In particular, since the thrust collar is manufactured separately from the rotor shaft, bearing characteristics are not affected by the material of the rotor shaft, making it possible to match the operating conditions of rotating equipment and improve bearing characteristics. The thrust collar can be formed by selecting an appropriate material.

(Example) Next, an example of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a sectional view showing an embodiment of the present invention,
An example in which the present invention is applied to a steam turbine of a USC power plant is shown. Note that the same elements as those in the conventional example shown in FIG. 3 are given the same reference numerals, and redundant explanation thereof will be omitted.

That is, the thrust bearing device 6 for rotating equipment according to this embodiment
a is a rotor shaft 8a of an adjacent rotating device.

8b are connected in the axial direction by a shaft coupling, and each rotor shaft 8
In a thrust bearing device for a rotating device, the rotor shafts 8a, 8b of adjacent rotating devices receive a thrust force generated when rotating the rotor shafts 8a, 8b together and hold the axial position of each rotor shaft 8a, 8b at a predetermined position. A pair of shaft joint hubs 19a connecting the shafts 8b.

19b, a pair of thrust collars 24a that are arranged on the opposite side of the joint surface of each shaft joint hub 19a, 19b, and integrally formed on each shaft joint hub 19a, 19b so as to face each other in the axial direction; 24b and both thrust collars 2
4a and 24b at fixed positions in the axial direction.

Furthermore, since the rotor shafts 8a and 8b are both in direct contact with high-temperature steam, they are made of high Cr steel with excellent creep strength, while the shaft coupling hubs 19a and 19b are not in direct contact with high-temperature steam. Rather, it is made of Cr-Mo-V steel with high thermal conductivity in consideration of bearing characteristics. The shaft coupling hubs 19a and 19b are respectively connected to the rotor shaft 8.
The key 20a is press-fitted into the ends of the keys 20a and 8b by shrink fitting.
.

20b, and the joint surface 2
5, they are connected by a shaft coupling bolt nut 26 so as to abut each other. In addition, each thrust collar 24a, 24b
Thrust bearing pads F10a, 10b are disposed in sliding contact with the end faces of the thrust bearing pads F10a, 10b, and a thrust bearing main body 11a is disposed that holds the thrust bearing pads 10a, 10b in a sandwiching manner. A bearing outer ring 14 is disposed via a curved seat 12a formed on the outer peripheral surface of the thrust bearing main body 11a, and the bearing outer ring 14 is fixed so as to fit into the bearing stand 13.

In addition, in order to prevent the lubricating oil filled in the thrust bearing body 11a from leaking, an oil cutter 15 is provided on the inner circumferential surface of the bearing body 11a to protrude in the direction of each thrust collar 24a, 24b.
a, 15b are respectively arranged, while each rotor shaft 8a
, 8b, a seal ring 16a is provided on the inner circumferential surface of the bearing body 11a facing the bearing body 11a.

16b is fitted.

When a USC power plant equipped with a thrust bearing device configured as described above is operated, the rotor shaft 8a is mainly affected by the pressure difference before and after the special stage of the steam turbine.

A thrust force is generated in the axial direction of 8b. This thrust force is applied from each rotor shaft 8a, 8b to the shaft coupling hub 19a, 19.
transmitted to b. Since the shaft joint hubs 19a, 19b and the thrust collars 24a, 24b are integrally formed, the thrust force is
The force is transmitted from the thrust bearing body 11a to the bearing stand 13 fixed at a predetermined position via the bearing outer ring 14. Therefore, the rotor shaft 8a due to the thrust force.

The displacement of 8b in the axial direction is effectively suppressed, and the function as a thrust bearing is exhibited.

In particular, since the thrust collars 24a and 24b integrally formed on the shaft coupling hubs 19a and 19b are made of Cr-Mo-V steel with excellent thermal conductivity, overheating in the thrust collars 24a and 24b is minimized. , the occurrence of galling can be effectively prevented.

That is, according to this embodiment, the shaft coupling hub 1 made of Cr-Mo-V steel is press-fitted into the rotor shafts 8a and 8b by shrink fitting.
A thrust collar 24a is attached to a part of 9a and 19b, respectively.
24b is integrally formed, even if the rotor shaft 8a
, 8b are made of high Cr steel, it is possible to obtain a thrust bearing device which is not affected by this and has less occurrence of galling.

In addition, as shown in Fig. 4, a member with good thermal conductivity is prepared separately from the rotor shaft 8 and shrink-fitted to the thrust bearing, or as shown in Fig. 6, a member with good thermal conductivity is prepared separately from the rotor shaft 8 and is shrink-fitted to the thrust bearing. There is no need to weld the metal layers 23a, 23b to both sides of the thrust collar 9b, the number of mechanical parts of the thrust bearing device 6a is reduced, and manufacturing costs and maintenance costs can be significantly reduced.

In particular, the rotor shafts 8a and 8b are made of high Cr steel, and the shaft coupling hubs 19a and 19b are made of Cr-M.

By forming the -V steel, it is possible to significantly improve the reliability of a turbine operated under ultra-high pressure and high temperature steam conditions.

In the above embodiment, the shaft coupling hubs 19a and 19b were fixed to the adjacent rotor shafts 8a and 8b by shrink fitting, respectively, but one of the rotor shafts was made of Cr-Mo-V.
Even if the rotor is made of steel and the shaft coupling hub is formed integrally with the rotor shaft, the same effects as in the above embodiment can be obtained.

〔Effect of the invention〕

As explained above, in the thrust bearing device for rotating equipment according to the present invention, the thrust collar is integrally formed on each shaft joint hub, so unlike the conventional thrust collar, it was formed by cutting out the rotor shaft. The number of processing steps and the number of component parts can be reduced compared to the conventional case, and the manufacturing cost and maintenance cost of the thrust bearing device can be significantly reduced.

In particular, since the thrust collar is manufactured separately from the rotor shaft, bearing characteristics are not affected by the material of the rotor shaft, making it possible to match the operating conditions of rotating equipment and improve bearing characteristics. The thrust collar can be formed by selecting an appropriate material.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of a thrust bearing device for rotating equipment according to the present invention, FIG. 2 is a sectional view showing an example of the configuration of a steam turbine power generator, and FIG. 3 is a configuration of a conventional thrust bearing device. A cross-sectional view showing an example. Figure 4 is a cross-sectional view showing the structure of a conventional rotor shaft in which the thrust collar, journal sleeve, and shaft coupling hub are integrally fixed by shrink fitting. Figure 5 is a cross-sectional view showing welded metal on the outer circumference of the rotor shaft. FIG. 6 is a cross-sectional view showing the structure of a conventional rotor shaft in which a layer is formed. FIG. 6 is a cross-sectional view showing a conventional rotor shaft in which a welded metal layer is formed on both end surfaces of a thrust collar integrally formed on the rotor shaft. 1... High pressure turbine, 2... Intermediate pressure turbine, 3a. 3b...Low pressure turbine, 4a-4h...Journal bearing, 5a-5c, 5d...Shaft coupling, 6, 6a...
Thrust bearing device, 7... steam communication pipe, 8. 8a,
8b... Rotor shaft, 9.9a, 9b... Thrust collar 10a, 10b... Thrust bearing pad, 1
1,11a... Thrust bearing body, 12.12a...
・Curved seat, 13...Bearing stand, 14...Bearing outer ring, 1
5,15a. 15b...Oil drainer, 15a, 16b...Seal ring, 17...Journal sleeve, 18...Key,
19° 19a, 19b...shaft coupling hub, 20, 20a
, 20b...key, 21...welding metal, 22...
Key, 23a, 23b... Thrust collar, 25...
・Joint surface, 26...Shaft joint bolt nut. Representative Patent Attorney Noriyuki Chika Figure 2-83 Figure 4 Figure 5t! ! 6th yJ

Claims (1)

[Claims] A rotating device that connects the rotor shafts of multiple rotating devices in the axial direction using a shaft coupling, receives the thrust force generated when each rotor shaft rotates as a unit, and maintains the axial position of each rotor shaft in a predetermined position. A thrust bearing device includes a pair of shaft coupling hubs that connect rotor shafts of adjacent rotating equipment;
A pair of thrust collars are arranged on the opposite side of the joint surface of each shaft joint hub and integrally formed on each shaft joint hub so as to face each other in the axial direction. 1. A thrust bearing device for rotating equipment, comprising a thrust bearing body that is sandwiched in a fixed position from a direction.