JPH06129206A - Rotary machine - Google Patents

Abstract

PURPOSE:To enhance the reliability of a rotary machine by increasing the strengths of a metal of a bearing, a key, a seal member, a blade, a valve rod or the like. CONSTITUTION:In a rotary machine such as a stem turbine, in which a rotary shaft 2 is supported by a metal 6 of a slide bearing 5, the surface of the bearing metal 6 on which the rotary shaft 2 bears is made of a material which is conformable with the rotary shaft 2, such as a porous oil-impregnated bearing material or a low friction coefficient material. Further, the bearing metal 6 is formed, on the side remote from the side on which the rotary shaft 2 bears on, of a material which has a strength enough to bear against a load transmitted from the rotary shaft 2. Further, the zone between the materials is made of an inclining function material in which the afore-mentioned materials are mixed together in such a ratio that gradually changes. Further, a casing fixing key, a seal member between a static part and a movable part, a turbine blade, a valve rod for a steam control valve and the like are also made of similar inclining function materials.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary machine such as a steam turbine, and more particularly to a rotary machine having an improved structure of wear resistant and heat resistant parts.

[0002]

2. Description of the Related Art Generally, in rotary machines such as steam turbines, slide bearings are used to support a rotary shaft.
The plain bearing has a structure in which a bearing metal fixed directly to a turbine casing or the like has a built-in bearing metal that directly receives the rotating shaft. The bearing metal is divided into, for example, six portions on the circumference, and each bearing metal is supported by a detent pin. A base metal with sufficient strength such as steel or copper alloy is often used as the bearing metal, and a soft metal such as lead / tin alloy with good axial compatibility, such as white metal, is cast on the surface side that receives the rotating shaft. Is formed by.

During operation of a steam turbine or the like, high-speed and high-load rotation is performed, so that lubricating oil is supplied to the bearing metal portion from the outside and direct contact between the two is prevented. If the lubricating oil is insufficient, the bearing metal may come into contact with the rotary shaft, and the rotary shaft may be damaged.

Further, unlike a steam turbine or the like, in the case of a rotary machine in which it is difficult to supply a lubricating oil at a low speed and a low load, the bearing metal itself contains the lubricating oil, and the oil seeps out during rotation to lubricate the oil-impregnated bearing. Is applied. That is, a large number of fine holes are formed in the bearing metal of the oil-impregnated bearing, and these fine holes serve as an oil reservoir to attract the lubricating oil to the sliding surface due to the suction force due to the rotation during operation and the temperature rise of the rotating shaft. Exudes. When the operation is stopped, the suction force is lost and the shaft temperature is lowered to return to the normal bearing metal state.

[0005] In addition, as a bearing used without oil, there is a bearing that supports a rotating shaft by using a material having a small friction coefficient. This is called a solid lubrication bearing, and for example, carbon, graphite or the like is applied.

On the other hand, in the high and medium pressure turbine casing of a large turbine, a bearing base on which a bearing is mounted and a casing covering a rotary shaft are keyed, and the key is fastened and fixed to the bearing base by bolts. Used a lot.

Further, a plurality of radial seal fins for closing the gap are arranged at intervals in the axial direction of the rotor in a stationary portion surrounding the outer periphery of the rotor of the steam turbine with a gap. It

Further, a fin segment for adjusting the clearance is attached to a stationary portion surrounding the outer peripheral portion of the rotor blade of the steam turbine with a clearance through an expandable bellows,
A configuration is also adopted in which the fin segment can be moved in the radial direction of the rotor by the pressure difference of the working fluid supplied to the inside and outside of the bellows.

Further, in a low-pressure turbine or the like having a rotor that is rotationally driven by using wet steam as a working fluid, the rotor blades of the rotor are arranged in an environment where erosion is caused by collision of water droplets.

Furthermore, in the steam turbine, a valve for controlling the flow of the high temperature and high pressure fluid is provided.

[0011]

The bearing metal of the above-mentioned plain bearing has various problems. That is, for a plain bearing used in a steam turbine for supplying oil from the outside, white metal or the like having a good shaft familiarity is used on the side in contact with the shaft, but it is weak in strength alone. For this reason, it is formed by casting into a base material with sufficient strength of steel or copper alloy, but if the adhesive strength weakens due to improper casting conditions, the white metal will peel off from the base material, and smooth lubrication will occur. Bearings and rotating shafts may be damaged. In addition, among the bearings that do not require oil supply from the outside, the oil-impregnated bearing is weak in strength because a large number of holes are opened in the metal itself, and a very large load cannot be applied. Further, the solid lubrication bearing has low mechanical strength because carbon and graphite are used in the portion in contact with the rotating shaft.

Further, the key connection portions at both axial end portions (so-called cat foot portions) of the high and medium pressure turbine casings of the large turbine also have substantially the same problems as described above. That is,
The cat feet of the turbine casing have the horizontal surface of the upper half of the casing as the support surface for the bearing stand in order to achieve the centerline support, and the lower half of the casing is suspended in the upper half during operation. Therefore, the starting point of the vertical extension is the horizontal plane, and the center of the casing is always aligned with the center of the rotor of the bearing on the bearing stand. That is, the turbine casing is divided into a casing upper half, a casing lower half, and a bearing stand with the horizontal joint surface as a boundary, and the upper casing half slides on a running key fitted in the bearing stand. Since this running key is only fitted between the upper half of the casing and the bearing stand, it may move and fly out due to the frictional force due to thermal expansion when the turbine is started / stopped. For support, the support plate is fixed to the upper half of the casing with tightening bolts. Further, the axial thrust force of the casing generated by the thermal expansion at the time of starting and stopping the turbine is transmitted to the bearing stand by the two front and rear thrust keys fitted between the lower half of the casing and the bearing stand.

Since this thrust key is only fitted between the lower half of the casing and the bearing stand, the turbine start,
There is a possibility that it will move due to the frictional force due to thermal expansion when it is stopped and jump out, and to prevent it from moving out, the support plate is fixed to the lower half of the casing with tightening bolts. In the vicinity of the cat's foot, a hold-down bolt is used to fix the lower half of the casing to the bearing stand. The reason for installing the hold down bolt is to prevent the casing from being pushed up by the reaction force of the pipe connected to the casing when the upper half of the casing is opened. This hold down bolt fixes the lower half of the casing and the bearing stand with a nut and a spherical washer, but floats the nut so that it can move even when it thermally expands when the turbine is started and stopped, and with the spherical washer it can move to the front, rear, left and right. I am able to move.

However, the key of the high and medium pressure turbine casing has the following problems. When the turbine is started, the temperature of the high- and medium-pressure turbine casing rises, and the cat feet move outward due to thermal expansion. On the other hand, the bearing stand that supports the upper half of the casing via the running key does not expand as much as the upper half of the casing because the temperature is low.
Therefore, slippage occurs between the upper half of the casing, the running key, and the bearing base. However, if the sliding condition between the running key and the bearing base is not good, slippage occurs between the upper half of the casing and the running key, and if the amount is large, the notch of the ranking key and the support plate will increase. Contact with and generate excessive force. Cracks may occur at the corners of the notch due to repeated start and stop.

Similarly, regarding the thrust key, when the turbine is started, the temperatures of the high and medium pressure turbine casings rise, and the cat feet expand in the direction perpendicular to the axis. On the other hand, the bearing stand
Since the temperature does not rise compared to the lower half of the casing, it does not expand as much as the lower half of the casing. Therefore, slippage occurs between the lower half of the casing, the thrust key, and the bearing base. Further, when the turbine is cooled, it shrinks by the amount of thermal expansion. At this time, a force that pushes back the thrust key acts on the support plate, and if the sliding state of the thrust key is bad, an excessive force acts on the support plate due to a large frictional force. As a result, the support plate is deformed and the tightening bolt is damaged, and the thrust key is pulled out due to repeated start and stop.

Further, the running keys and thrust keys mostly use cast iron as a material having excellent slidability. This material has low tensile strength and is brittle, so
It is not suitable for use in places where excessive force is generated.

On the other hand, there is also a problem with the radial seal fins (hereinafter abbreviated as "seal fins") provided on the inner diameter of the ring of the steam turbine rotor and the packing which is the stationary portion.

That is, in the conventional shaft seal structure, when the rotor and the seal fin contact each other, a shaft vibration called rubbing occurs. As a leaf spring mechanism, it has a structure that absorbs excessive contact force.However, the seal fin with the tip sharpened is often deformed and bent due to contact, and the contact is caused by the bent seal fin. Frictional heat increases, and in the worst case, the rotor bends,
Excessive shaft vibration is a major obstacle to turbine operation.

However, the wear of the tips of the seal fins due to very slight contact has an advantageous effect on the performance of the turbine with the minimum gap between the rotor and the seal fins being the minimum and optimum value. However, in recent years, there is a tendency that rubbing due to very slight contact is not preferred, and the gap between the rotor and the seal fin has to be set to a large value so that contact does not occur as much as possible, which sometimes conflicts with performance improvement. .

Here, the seal fin is often made of high-strength, high-Cr alloy steel for high-pressure, high-temperature steam, and even if the tip is sharpened, the influence of contact on the rotor is avoided. Absent. Therefore, even if the rotor and the seal fin are in contact with each other, minimizing the influence on the rotor is an issue for improving the reliability of the steam turbine without deteriorating the performance.

Also in the turbine seal clearance adjusting device, there are problems in the degree of damage, performance, reliability and the like when the fin segment and the turbine rotating part come into contact with each other during operation.

In other words, in recent years, it has become increasingly important to improve turbine performance in response to soaring fuel prices, and various performance improvement measures have been proposed. The most effective performance improvement measures are The purpose is to reduce the amount of steam leaking from the gap between the stationary part and the rotating part, which inevitably exists in each part of the turbine.

In the assembly of a conventional steam turbine of this type, in the upper half, tip fins, nozzle packings, and nozzle fins are provided between the rotor vane and the nozzle outer ring implanted in the turbine axle, and between the turbine axle and the casing, respectively. A sealing device such as a gland packing for preventing vapor leakage is provided.

As such a sealing device, a dovetail-shaped mounting groove extending in the circumferential direction is formed in a portion of the nozzle outer ring, which is a stationary portion, facing the outer peripheral end of the moving blade, and the mounting groove has the mounting groove of the moving blade. There is one in which a segment provided with a plurality of circumferentially extending seal fins protruding toward the outer peripheral surface is mounted.
Then, a predetermined minute gap is formed between the seal fin and the tip of the rotor blade that is the rotating body, and the vapor leakage is kept to a minimum through this gap.

By the way, the main factor that determines the steam leakage prevention effect in this type of non-contact type sealing device is
It is the size of the gap between the tip of the seal fin and the rotating part,
The smaller this gap, the smaller the amount of leakage, but if this gap is made too small, the seal fin and the rotating part will come into contact during operation, the rotating part and the seal fin will be damaged, and the shaft vibration will increase due to the contact, and There are problems that it is impossible to continue, and the rotating part is bent due to heat generated by contact.

Such contact is because the gap changes depending on the operating state of the turbine, and such changes include various deformations such as uneven deformation of the casing, deformation due to pressure, and the support characteristics of the bearing that supports the axle. It is caused by the above factors, and is particularly generated when the turbine is started or stopped, or when the load changes.

During steady operation, the amount of deformation and variation settles down to a constant value over time, so the amount of change in the gap is extremely small, and if the gap is set in consideration of the state of the gap when starting and stopping or when the load changes, it will take a long time. During steady operation over
The gap becomes unnecessarily large and the amount of steam leakage increases.

In order to eliminate such a problem, conventionally,
It has been proposed that a drive mechanism is provided between the fin segment and the stationary portion, and a movable seal mechanism that changes the gap according to an operating state or an actually measured value of the gap of the seal portion is provided.

As a conventional movable seal gap adjusting device, a segment mounted in a mounting groove is connected to a flange body through an expandable inner pressure type bellows, and this flange body is connected to a nozzle through a mounting bolt. Some are fixed to the outer ring. The nozzle outer ring has a working fluid inlet hole
The introduction hole communicates with the inner chamber of the bellows through a communication hole provided in the mounting bolt.

The outer chamber located outside the bellows is filled with the working fluid of the turbine flowing in through the gap between the segment and the outer ring of the nozzle, and the pressure of the working fluid in the outer chamber and the pressure of the working fluid in the inner chamber are filled. The bellows are expanded and contracted in the radial direction by the differential pressure. When the pressure P _{1 in the} inner chamber is higher than the pressure P ₂ generated by the working fluid of the turbine in the outer chamber, the pressure difference causes the bellows to expand, narrowing the gap between the tip of the seal fin provided in the segment and the moving blade. , Leakage of steam is prevented.

However, this seal gap adjusting device using the internal pressure type bellows has the following problems. A bottom plate made of a stainless steel material is provided at the tip of the bellows. In order to prevent leakage of the working fluid in the inner chamber, the bellows and the bottom plate are electron beam welded (EB
It is fixed at W) and maintains airtightness. Further, since the segment expands and contracts in accordance with the expansion and contraction of the bellows, the bottom plate and the segment are joined at the fillet weld.

Since the segment is welded to the bottom plate and a material having good weldability with the bottom plate made of a stainless steel material is selected, an alloy steel having a high hardness is used. Therefore, the pressure difference ΔP = P ₁ −P ₂ between the inner chamber and the outer chamber becomes large at the time of starting / stopping or at the time of stopping the load, and the seal fin extends,
If the gap with the outer peripheral edge of the moving blade becomes smaller and should it come into contact, the segment will be made of alloy steel with high hardness, so the outer peripheral edge of the moving blade and the seal fins will be damaged, or the shaft vibration will increase due to contact. Further, damage to the rotor blades and seal fins widens the gap, resulting in problems such as deterioration in performance.

There is also a problem with the blades of the steam turbine. A steam turbine is a prime mover that converts the thermal energy of steam into kinetic energy to generate mechanical output. In the process of generating mechanical output, the thermal energy is lost, water condensation begins, and water droplets are generated. In the steam turbine including the turbine high-pressure portion and the turbine low-pressure portion, such generation is remarkable in the turbine low-pressure portion, and particularly, the amount of erosion caused by the water droplets colliding with the blade in the final stage of the low-pressure portion is large.

Consider the construction of the last section of the turbine low pressure section. Turbine blades are planted in the turbine rotor. A turbine nozzle is adjacently provided on the inlet side of the turbine blade, and a so-called turbine blade and turbine nozzle form a paragraph, and the thermal energy of flowing working steam is converted into mechanical output.

The state of drain generation and blade erosion in the final paragraph will be described. It loses heat energy as it passes through many paragraphs up to the final paragraph, and is condensed into saturated vapor. Initially, the water droplets in the saturated steam are as small as a few μ or less, and the inertial force is also small, so most of them fall on the steam flow in the paragraph. However, since there are many nozzles and blades in the turbine, they grow to a diameter of 50 μm or more while colliding with and detouring against them.

When the vapor containing such water droplets flows into the nozzle in the final paragraph, the water droplets collide with the nozzle leading edge portion and the ventral surface portion and are collected to form a water film flow on the blade surface of the nozzle. The water film flow is jetted again from the trailing edge in the steam to form coarse water droplets of about several hundred μ, which collide with the final stage blade. At this time, since the water droplet has a large diameter and is slower than the steam flow velocity, the water droplet collides with the blade at a relatively high speed from the back surface of the blade. This is the reason why drain erosion of the last stage blade occurs.

As a countermeasure against this erosion, silver brazing or welding is used from the blade entrance to the back surface, which is conventionally subject to a lot of erosion.
Erosion shield plates made of stellite and tool steel, which are not easily corroded, are attached. On the other hand, as another countermeasure against erosion, the portion to be eroded is flame-hardened to increase the hardness in order to have erosion resistance.

However, the conventional methods of attaching the erosion shield plate by silver brazing and welding have the following problems, respectively.

When the erosion shield plate is attached by silver low, since the erosion shield plate is long at the time of manufacturing, uneven adhesion occurs on the silver low between the blade and the erosion shield plate, or the end part is badly attached to cause erosion during operation. Problems such as peeling of the shield plate occur. Further, there is a possibility that the erosion shield plate may be peeled off due to corrosion of the silver brazing part during operation. Separation of erosion accelerates blade erosion, deteriorates turbine performance, and is dangerous as it scatters.

On the other hand, when the erosion shield is attached by welding, the base material in the vicinity of the welding is affected by the heat of welding, and the fatigue strength is reduced. During operation, the vane is subjected to a large centrifugal force and a complex vibration stress due to the steam force, and thus cracks may occur in the heat-affected zone of the weld with reduced fatigue strength. If this crack propagates and the blades scatter, there is a danger of a serious accident.

Like the welding heat affected zone, flame quenching of the eroded area is affected by the heat of the base material and the fatigue strength is lowered, so that cracks are likely to occur in that area, and the same problem as in the above case occurs. .

Furthermore, a steam valve for controlling the amount of steam flowing into the steam turbine is provided at the inlet of the steam turbine. The steam generated in the boiler passes through the main steam pipe, the main steam stop valve, and the steam control valve, enters the high pressure turbine through the reed pipe, works while expanding, and is reheated through the low temperature reheat pipe and reheater. It becomes a high temperature, enters the medium pressure turbine through the high temperature reheat pipe, reheat steam stop valve, intercept valve, does work and is guided to the low pressure turbine through the crossover pipe,
After working, he enters the condenser and is cooled to water.

Explaining the steam control valve in this,
The inflowing steam flows in from the inlet side of the steam control valve body, passes through the throttle portion of the valve and the valve seat, flows downstream of the valve seat, and flows to the reed pipe.

The valve is screwed to the crosshead by the valve stem. The valve rod is guided by the bush and serves to block the inside of the main body from the outside.
The crosshead is driven by a lever. One end of the lever is a fulcrum and the other end is a drive mechanism (generally hydraulic equipment)
It is connected to the. The valve rod is exposed to high temperature and high pressure on the side connected to the valve, while the screw portion connected to the crosshead is in the atmosphere, and the temperature is determined by heat conduction. For this reason, the material of the valve rod is a material having high strength at high temperature (mainly creep rupture strength), and a material which is uniform throughout is used.

However, since the connecting portion with the crosshead is connected by screws, it is desirable that the cyclic fatigue strength under high stress is high. However, a material having high creep rupture strength at high temperature is brittle and has low toughness at low temperature. Therefore, in the threaded portion, stress concentration due to the notch effect and brittle material characteristics tend to cause cracks in the root of the thread.

Therefore, conventionally, a large R groove is provided at the thread cutting start portion of the thread portion where stress concentration is likely to occur on the valve rod.
We are trying to reduce stress concentration. However, it is very difficult for the steam control valve stem to achieve the required two functions with a uniform material.

A. High temperature part in contact with steam High temperature creep rupture strength and material with high fatigue b. Screw connection part Usually, at 200 to 300 ° C, the humidity increases due to the steam leaking through the gland part of the valve rod. For this reason, the material has high notch fatigue strength due to screws and is resistant to stress corrosion in a humid atmosphere.To achieve these materials, the conventional valve rod is made entirely of a material with high temperature creep strength to reduce stress concentration in the threaded portion. For this reason, a large R groove is provided at the beginning of thread cutting to reduce stress concentration, and the portion below it has a very small clearance with the crosshead to reduce deformation due to bending that acts on the valve rod and to prevent ingress of wet steam. It is intended to reduce the effect. Even with this structure, it is not possible to prevent pitting corrosion on the surface of the thread portion of the valve rod due to invasion of wet steam.

In some cases, when pitting corrosion occurs, stress concentration occurs in this portion and becomes a starting point of cracking. The same applies to the valve stem of the steam valve of the steam turbine, which has the high temperature strength and the fatigue strength matched by the valve stem connecting the main valve for controlling the flow of the high temperature and high pressure steam and the drive mechanism, and which is hard to break.

The present invention has been made in view of the above circumstances, and a first object thereof is to increase the strength of the bearing metal of a bearing in a rotary machine to improve the reliability.

The second purpose is to start up a rotary machine.
The key is to prevent the key from moving due to frictional force due to thermal expansion at the time of stop, to prevent damage to the key, and to improve reliability.

A third object is that in a rotating machine, even if the rotor and the seal fin come into contact with each other, the influence on the rotor can be made as small as possible, and the shaft vibration caused by the contact can be made small. The gap is set small at the time of assembly so that the gap is optimized for performance due to wear of the tip of the seal fin due to very slight contact.

A fourth object of the present invention is to reduce the gap between the seal fins of the seal gap adjusting device and the outer peripheral end of the moving blade in a rotary machine, and even if they come into contact with each other, the outer peripheral end of the moving blade is damaged or the shaft vibration is generated. Is to improve reliability and safety by preventing the increase in

A fifth object of the present invention is to improve performance and improve safety in a rotary machine by making the base material of the turbine blade itself have sufficient fatigue strength and also having erosion resistance on the blade back surface against which water droplets collide. Is to try.

A sixth object is to improve the high temperature creep rupture strength and fatigue strength of a valve rod used for a valve body in a rotary machine, which is exposed to high temperature and high pressure, and the corresponding corrosion resistance in a humid atmosphere. Especially.

[0055]

According to a first aspect of the present invention, in a rotary machine in which a rotary shaft is supported by a bearing metal of a sliding bearing, a surface of the bearing metal that receives the rotary shaft is compatible with the rotary shaft. A material having good strength, a porous oil-impregnated bearing material, or a material having a low friction coefficient, and a material having a strength sufficient to support a load from the rotating shaft on the side opposite to the side receiving the rotating shaft. And a region between the two materials is made of a functionally graded material in which the ratio of the two materials changes in a graded manner.

According to a second aspect of the present invention, a bearing base on which a bearing for supporting a rotary shaft is mounted and a casing that covers the rotary shaft are keyed together, and the key is fastened and fixed to the bearing base by bolts. In the above, the casing facing surface side of the key is made of a material having excellent slidability, while the bolt fastening side of the key to the bearing base is made of a high-strength alloy steel material, and a region between the both materials. Is composed of a functionally graded material in which the ratio of both materials changes in a graded manner.

According to a third aspect of the present invention, a shaft in which a plurality of radial seal fins for closing the gaps are arranged at intervals in the axial direction of the rotor in a stationary portion that surrounds the outer peripheral portion of the rotor with a gap. In a fluid-flow rotary machine, the tip side of the radial seal fin is made of a functionally graded material having a friction coefficient lower than that of a material of the base end side.

According to a fourth aspect of the present invention, the fin segment for gap adjustment is mounted on a stationary portion surrounding the rotor blade outer peripheral portion of the rotor with a gap interposed therebetween, and the fin segment is supplied to the inside and outside of the bellows. In the axial flow fluid type rotary machine in which the fin segment is movable in the radial direction of the rotor by the pressure difference of the working fluid, the side of the fin segment facing the rotor is made of a non-ferrous material or a low hardness material. On the other hand, it is characterized in that the bellows mounting side of the fin segment is made of a good weldability material, and the region between the two materials is made of a functionally graded material in which the ratio of the two materials changes in an inclined manner.

According to a fifth aspect of the present invention, there is provided a rotary machine having a rotor rotatably driven by using moist steam as a working fluid,
In a rotor in which the rotor blades are arranged in an environment where erosion occurs due to collision of water droplets, the steam inlet rear surface that is eroded by water droplets in the rotor blade is made of a material having high erosion resistance, while The part that is not eroded is composed of a material having high strength against centrifugal force or steam force acting during operation, and the region between the both materials is composed of a functionally graded material in which the ratio of both materials changes in a sloping manner. Characterize.

According to a sixth aspect of the present invention, there is provided an axial flow fluid type rotary machine having a valve for controlling a flow of a high temperature and high pressure fluid, wherein a valve connecting the valve and a drive mechanism for driving the valve. The rod, the connecting side with the valve is made of a material with high temperature creep rupture strength, while the side connected with the drive mechanism is made of a material with high fatigue strength due to stress amplitude and strong against stress corrosion, and It is characterized in that the region between the two materials is made of a functionally graded material in which the ratio of the two materials changes in an inclined manner.

[0061]

According to the first aspect of the invention, the side of the bearing metal that receives the shaft is made of a material having good lubricating characteristics, a porous material containing lubricating oil, or a material having a small friction coefficient, and the opposite side supports the load from the shaft. A material with sufficient strength to
By using the functionally graded material in the middle portion, it is possible to improve the reliability of the bearing without causing peeling or the like while having good lubricating properties and sufficient strength.

According to the invention of claim 2, in the cat foot of the high and medium pressure turbine casing, the key can be prevented from being damaged by the frictional force due to the thermal expansion at the time of starting and stopping the turbine, and the reliability and the safety are greatly improved. Can be made.

According to the invention of claim 3, a steam turbine,
Even if there is a contact between the rotor and the radial seal fin of the shaft seal device of an axial fluid machine such as a gas turbine or an axial compressor, it is possible to prevent excessive rotor vibration from occurring and at the same time to prevent contact friction. It is possible to prevent the phenomenon that the rotor bends and the shaft vibration is further promoted. Due to these effects, the gap between the rotor and the radial seal fin is set smaller than the planned value when assembling the axial fluid machine, and the leakage fluid is reduced due to wear of the tip of the radial seal fin due to extremely slight contact, which optimizes performance. It can be a gap and can contribute to performance improvement.

According to the fourth aspect of the present invention, even if the fluid pressure difference becomes large in the gap between the stationary portion and the rotor and the gap becomes small, and the fin segments come into contact with each other, the moving blades are not damaged. Turbine operation is possible, and reliability and safety can be greatly improved.

According to the fifth aspect of the present invention, a material having erosion resistance is used for the portion on the back side of the inlet where the blade is easily eroded by water droplets, and the other portions which are not eroded are subjected to centrifugal force acting during operation. The blade material itself has erosion resistance because a material capable of withstanding steam and steam power is used and a functionally graded material is used between them. Therefore, it is not necessary to attach the erosion shield plate or flame-harden the base material to increase the erosion resistance, and it is possible to prevent the flaking of the erosion shield plate and the decrease in fatigue strength due to it, which can reduce the reliability and safety of the blade. It is possible to improve the property.

According to the sixth aspect of the present invention, the side of the valve rod exposed to the high-temperature and high-pressure steam is resistant to high stress, and the portion in the intermediate bush has a rapid oxide film growth due to the steam oxidation resistance. Since sliding is ensured and the threaded portion is ensured to have fatigue strength in a corrosive environment, factors that cause breakage of the valve stem are suppressed, and the life of the valve stem is extended to improve reliability and safety. In addition, since the functionally graded material does not have a clear boundary, there is no restriction on the material combination such as austenitic heat-resistant steel for the high temperature part and ferritic or martensitic corrosion resistant material for the screw part, and there is no restriction on the material combination, and the linear expansion It is possible to reduce the thermal stress caused by the difference in elongation due to the difference in coefficient.

[0067]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIGS. 1 to 7 This embodiment relates to a steam turbine having an improved bearing structure. FIG. 1 shows the overall structure of the turbine, FIG. 2 and FIG. 3 show refueling bearings, and FIG. 4 and FIG. 5 is an oil-impregnated bearing, FIGS. 6 and 7.
Indicate solid lubrication bearings.

As shown in FIG. 1, in the steam turbine of this embodiment, a rotary shaft 2 in which a moving blade 1 is implanted is arranged in a casing 3, and is guided to a nozzle diaphragm 4 in the casing 3 as shown by an arrow A. The high-temperature and high-pressure steam becomes a high-speed jet flow, hits the moving blade 1, and rotates the rotating shaft 2 to obtain a driving force. Both ends of the rotary shaft 2 are supported by bearings 5 outside the casing 3.

The bearing 5 shown in FIG. 2 is a refueling bearing, and is a rotary shaft 2
And a bearing main body 7 with an oil passage 7a which is fixed in the casing 3 by incorporating the bearing metal 6 therein. The bearing metal 6 is divided into a plurality of parts in the circumferential direction, for example, divided into six parts, and each is supported by the bearing body 7 by a rotation stop pin 8.

During operation of the steam turbine, as shown by the arrow B in FIG. 2, the lubricating oil is supplied from the outside to the oil passage 7a of the bearing main body 7, passes through the inner surface of the bearing metal 6 and is discharged to the outside as shown by the arrow C. To be done.

In this structure, each split element 6a constituting the bearing metal 6 has a rotary shaft 2 as shown in FIG.
The region D on the inner surface side that receives the load is made of a material having a good axial compatibility, for example, a soft alloy of lead or tin, and the region F extending from the central portion in the thickness direction to the anti-bearing surface on the outer peripheral side is subjected to the load from the rotary shaft 2. On the other hand, it is made of steel or a copper alloy material having sufficient strength, and the region E between these materials is made of a functionally graded material in which the composition ratio of both materials of the region D and the region F gradually changes. As an integral structure.

Unlike the conventional bearing structure in which the bearing metal is made of a joining material, the bearing 5 having such a structure has no clear boundary between the materials, so that peeling or the like occurs during operation due to manufacturing defects or the like. Never. In other words, the conformability of the shaft on the side receiving the rotary shaft 2 is good, and in terms of strength, the region F bears the axial load, so that the weakness of the material in the region D can be compensated.

Therefore, not only in the normal operation state in which the lubricating oil is normally supplied, but also in the case where the rotating shaft 2 and the bearing metal 6 come into contact with each other due to insufficient lubricating oil, the rotating shaft 2 is Since it has sufficient strength without being damaged by the peeling of the receiving surface, the damage prevention of the rotary shaft 2 can be greatly improved, the reliability is improved, and the safety of the rotating machine can be secured.

The bearing 5 shown in FIG. 4 is an oil-impregnated bearing, and the rotary shaft 2
The bearing metal 11 that directly receives is divided into two in the circumferential direction, for example, and this bearing metal 11 is built in the bearing body 7.

Then, as shown in FIG. 5, the bearing metal 11
The region G on the side receiving the rotating shaft 2 is made of a porous material, for example, a metal such as copper, iron or aluminum, and is made porous, and the region I on the side opposite to the bearing surface from the central portion in the thickness direction is the rotating shaft. Two
Is composed of a material such as steel having a sufficient strength against the load from, and the region H between the two materials is composed of a functionally graded material in which the material composition of the regions G and I gradually changes, forming an integrated structure as a whole. I am doing it. According to such a configuration, since the region G side facing the rotating shaft 2 is porous, the oil oozes out during the shaft rotation by including oil in the hole, and lubrication is performed,
A large load from the rotating shaft 2 is supported by the region I, and the strength of the porous region G is supplemented. Also, even in such an oil-impregnated bearing structure, unlike the conventional structure in which the bearing metal is made of a joining material, there is no clear boundary between the materials, so the strength is high, and it is less likely to be damaged even when a large load is applied. Can improve your trust.

The bearing 5 shown in FIG. 6 is a solid lubrication bearing, and the bearing metal 12 for solid lubrication that directly receives the rotary shaft 2 is divided into, for example, two in the circumferential direction, and this bearing metal 12 is the bearing main body 7.
Is built into.

As shown in FIG. 7, in the bearing metal 12 for solid lubrication, the region J in contact with the rotating shaft 2 is made of a material having a small friction coefficient, for example, carbon and graphite. The region L on the bearing surface side is made of steel or copper alloy having sufficient strength against an axial load, and the region K between them is made of a functionally graded material in which the material composition of the regions J and L gradually changes. The entire structure is integrated.

According to the solid lubrication bearing having such a structure,
Since the friction coefficient is small on the region J side in contact with the rotating shaft 2, the rotating shaft 2 can be smoothly supported, and the weak portion of the strength is supported by the region L.

Even in such a solid lubrication bearing structure,
Unlike the conventional structure in which the bearing metal is made of a joining material, there is no clear boundary between the materials, so the strength is high, it is less likely to be damaged even when a large load is applied, and the reliability of the rotating machine can be improved.

(Embodiment 2) FIGS. 8 to 13 This embodiment relates to a steam turbine in which the key structure of the cat's foot is improved. FIG. 8 shows the overall structure of the turbine, and FIG. 9 shows the cat's foot (see FIG. 8). Circle portion), FIGS. 10 and 11 show thrust keys (FIG. 10 shows a sectional view taken along line XX of FIG. 9), and FIG.
And FIG. 13 shows a running key (FIG. 12 shows XII in FIG. 9)
-XII sectional shape) is shown.

As shown in FIGS. 8 and 9, in this embodiment, the turbine casing 21 is divided into a casing upper half 21a and a casing lower half 21b with the horizontal joint surface 22 as a boundary, and the bearing pedestals are provided at both ends of the casing. 23 are provided.

The casing upper half 21a slides on the running key 24 fitted in the bearing stand 23. The running key 24 is tightened with a tightening bolt 25 so that the running key 24 does not move due to frictional force due to thermal expansion when the turbine is started and stopped.
Is fixed to the bearing stand 23.

The axial thrust force of the casing 21 caused by the thermal expansion at the time of starting / stopping is generated by the two thrust keys 26, which are fitted between the lower half 21b of the casing and the bearing stand 23, in the bearing stand 23. Transmitted to. The thrust key 26 is fixed to the bearing base 23 with a tightening bolt 27 so as not to move due to a frictional force due to thermal expansion when the turbine is started and stopped. 28 and 2 in FIG.
Reference numerals 9 and 30 denote nuts for fixing the casing upper half 21a and the casing lower half 21b to the bearing stand 23, respectively.
A spherical washer and a holddown bolt.

Between the casing 21 and each of the keys 24 and 26, frictional force due to thermal expansion at the time of starting and stopping the turbine causes
Sliding occurs as shown by arrows a and b in FIGS. 10 and 12.

Therefore, as shown in FIG. 12 and FIG.
The thrust key 26 and the ranking key 24 each have an L region facing the casing 21 made of a material having excellent slidability, while an M region fixed with a tightening bolt is made of alloy steel. The region is composed of a functionally graded material in which the material composition of both the L region and the M region gradually changes.

As a result, even when used under severe operating conditions such as when the turbine is started and stopped, the functionally graded material may peel off or crack like cast iron because it is a material without a clear boundary. Therefore, it is possible to prevent key damage, improve the reliability of the turbine, and safely operate the turbine.

(Embodiment 3) FIGS. 14 to 16 This embodiment relates to a steam turbine in which a radial seal fin (hereinafter abbreviated as “seal fin”) is improved, and FIG. 14 shows the structure of the seal fin. 15 shows an XV-XV sectional structure of FIG. 14, and FIG. 16 shows an enlarged structure of a main part.

In the present embodiment, the ring-shaped packing 32 as a stationary portion surrounding the outer peripheral portion of the rotor 31 with a gap is provided with the seal fin 33 for closing the gap so as to minimize the leaked steam. It is arranged at intervals along the axial direction. That is, the seal fin 33 has a multi-stage structure in the axial direction of the rotor, and steam passing through the minute gap δ between the rotor 31 and the seal fin 33 as indicated by an arrow c is generated between the seal fin 33 and the seal fin 33 adjacent in the axial direction. By expanding the space one after another, the sealing effect is enhanced.
It should be noted that the rotor 31 is processed to have irregularities, and the sealing effect is further enhanced by disposing the high and low seal fins 33.

In this structure, the tip portion 34 of the seal fin 33 is made of a material having a coefficient of friction lower than that of the base material (base material) of the seal fin 33, and the portion between them has an inclined function in which both materials gradually change. Composed of materials. It is sufficient that the tip portion made of a material having a low coefficient of friction is within a range of several mm or less from the tip of the seal fin. In FIG. 15, reference numeral 35 is a leaf spring that biases the packing 32 toward the inner peripheral side.

At the boundary between the base material of the seal fin 33 and the low friction coefficient material, the low friction coefficient material and the base material are firmly bonded by the functionally graded material, so that there is no problem in the strength of the seal fin 33. . The tip of the seal fin may be sharpened at an acute angle if necessary.

The packing 32 and the seal fin 33 are the same as in the case of the integrally cut-out type. In this case, the base material of the packing 32 is made of a material having a low friction coefficient directly in a gradient composition. As the low friction coefficient material, carbon, Teflon, engineering plastic and the like can be applied.

In the conventional seal fin, the rotor is greatly affected by the contact with the rotor, but according to the present embodiment, the tip portion 34 of the seal fin 33 has a low friction coefficient, and the space between them is made of a functionally graded material. By,
Even if the seal fin 33 contacts the rotor 31, the rotor 31
At the same time no longer generating excessive shaft vibration
The contact friction prevents the rotor 31 from bending.

(Embodiment 4) FIGS. 17 to 20 This embodiment relates to a steam turbine having an improved outer peripheral seal structure, and FIG. 17 shows the seal structure.
18 to 20 respectively show fin segment configurations which are main components.

In the steam turbine of this embodiment, the rotor 41
A fin segment 44 is provided as a sealing device for preventing vapor leakage between the moving blade 42 and the nozzle outer ring 43 which are embedded in the nozzle. That is, a dovetail-shaped mounting groove 46 extending in the circumferential direction is formed in a portion of the nozzle outer ring 43, which is a stationary portion supported by the casing 45, that faces the outer peripheral end of the moving blade 42. The fin segment 44 is fitted and provided with a plurality of circumferentially extending seal fins 47 projecting toward the outer peripheral surface of the moving blade 42. This seal fin 47 and moving blade 4
A predetermined minute gap is formed between the tip and the second end, and vapor leakage from this gap is kept to a minimum.

In this structure, the fin segment 44 mounted in the mounting groove 46 is connected to the flange body 49 by a stretchable internal pressure type bellows 48 via a stainless steel bottom plate 44a welded to the surface thereof. . Reference numeral 44b in FIG. 19 indicates a welded portion. The flange body 49 is fixed to the nozzle outer ring 43 via mounting bolts 50.
A working fluid introduction hole 51 is formed in the nozzle outer ring 43, and the introduction hole 51 communicates with an inner chamber 53 of the bellows 48 through a communication hole 52 provided in the mounting bolt 50.

The outer chamber 54 located outside the bellows 48
Is filled with the working fluid of the turbine that flows in from the gap between the segment 44 and the outer ring 43 of the nozzle, and the bellows 48 is caused by the pressure difference between the pressure of the working fluid in the outer chamber 54 and the pressure of the working fluid in the inner chamber 53. It is designed to expand and contract in the radial direction. When the pressure P ₁ inside the inner chamber 53 is higher than the pressure P ₂ due to the working fluid of the turbine inside the outer chamber 54, the bellows 48 expands due to the pressure difference, and the tips of the seal fins 47 provided on the segment 44 and the moving blades. 42
The gap between and is narrowed, and steam leakage is prevented.

In this embodiment, however, the region O of the fin segment 44 on the side where it is welded and fixed to the bellows 48 is made of a material having a good weldability with the stainless steel material, while the side facing the rotor 41. The region P is made of a non-ferrous material or a material having a low hardness, and the region Q between them is made of a functionally graded material in which the ratio of both materials changes in an inclined manner.

As a result, even if used under severe operating conditions, the functionally graded material peels off because it is a material that has no clear boundaries,
Since no cracks will enter, the gap between the seal fin 47 and the outer peripheral edge of the moving blade 42 will be small, and a large accident will not occur even if they come into contact with each other, so that the turbine can be operated safely. Become.

(Embodiment 5) FIGS. 21 to 23 This embodiment relates to a steam turbine having an improved moving blade structure. FIG. 21 shows the entire structure of the moving blade, FIG.
The main parts of Haru's moving blade are shown.

As shown in FIG. 21, the steam turbine of this embodiment is applied to the last stage of the turbine low pressure section.
The turbine rotor blade 61 is embedded in the turbine rotor 62. A turbine nozzle 63 is provided on the inlet side of the turbine rotor blade 61.
Are adjacent to each other, and a so-called turbine moving blade 61 and a turbine nozzle 63 form a paragraph, and the thermal energy of the working steam flowing in the direction of the arrow d is converted into a mechanical output.

FIG. 22 shows a state in which the vicinity of the outer periphery of the moving blade 61 of FIG. 21 is viewed from the half direction, and the generation of drain and the erosion of the moving blade 61 in the final paragraph will be described. As the steam loses heat energy as it passes through many paragraphs to the final paragraph, it is condensed to saturated vapor. Initially, the water droplets in the saturated steam are as small as a few μ or less, and the inertial force is also small, so most of them fall on the steam flow in the paragraph. However, since there are a large number of nozzles and moving blades in the turbine, they grow to a diameter of 50 μm or more while colliding with and detouring against them.

When the vapor containing such water droplets flows into the nozzle 63 in the final paragraph, the water droplets collide with the front edge portion and the abdominal surface portion of the nozzle 63 to be collected, and the water film flow 64 on the blade surface of the nozzle 63. And the water film flow 64 is jetted again in the steam from the trailing edge to form coarse water droplets 65 of about several hundred μ, and the final stage rotor blade 6
Clash with 1. At this time, since the water droplet 65 has a large diameter, it is slower than the steam flow velocity and relatively collides with the moving blade 61 from the back surface of the moving blade 61 at a high speed. This is the reason why the drain erosion of the final stage moving blade 61 occurs.

In this embodiment, as shown in FIG. 23, the moving blade 6
The region RR on the back side of the steam inlet that is corroded by the water droplet 1 is made of a material having high corrosion resistance, such as stellite, ceramics, or tungsten, while the rotor blade 61 is used.
The region S that does not undergo erosion from the central part to the outlet part is made of a material such as 12Cr steel having sufficient strength against centrifugal force or steam force, and the region T between the region R and the region S is It is composed of a functionally graded material in which the ratio of both materials changes in a slanted manner.

According to the present embodiment, since the gradient functional material having no clear boundary is provided, the moving blade material itself has erosion resistance without peeling during operation. Since there is no need to perform welding, flame quenching, etc., the fatigue strength of the rotor blade material is not reduced by heat, and the effects such as safety in operation are exhibited.

(Embodiment 6) FIGS. 24 to 26 This embodiment relates to a steam turbine having an improved valve stem structure for connecting a main valve for controlling the flow of high-temperature and high-pressure steam with a drive mechanism. 24 is a steam turbine system configuration, FIG.
5 shows a valve structure, and FIG. 26 shows a valve stem structure.

First, the system configuration of the steam turbine will be described. As shown in FIG. 24, the steam generated in the boiler 71 is composed of a main steam pipe 72, a main steam stop valve 73, and a steam control valve 74.
Through the lead tube 75 and into the high pressure turbine 76,
It works while expanding, and is reheated through the low temperature reheat pipe 77 and the reheater 78 to reach a high temperature. And the high temperature reheat pipe 79,
After passing through the reheat steam stop valve 80 and the intercept valve 81, the medium pressure turbine 82 is entered, and the work is performed to cross the crossover pipe 83.
Through the low pressure turbines 84a and 84b, they work, enter the condenser 85, and are cooled to be condensed water.

The structure of the steam control valve 74 therein is shown in FIG. The steam control valve 74 is provided at the inlet of the steam turbine. The inflowing steam flows in from the inlet side of the steam control valve main body 90, passes through the throttle portions of the valve 91 and the valve seat 92, and passes through the valve seat 92.
Flow to the reed tube 75.

The valve 91 is constituted by a valve rod 93 and a crosshead 94.
It is connected with a screw. The valve rod 93 is guided by the bush 95 and also serves to block the inside of the steam control valve body 90 from the outside.

The crosshead 94 is driven by the lever 96. One end of the lever 96 serves as a fulcrum 97, and the other end 98 is connected to a drive mechanism (generally a hydraulic device) 99.
The valve rod 93 is exposed to high temperature and high pressure on the side connected to the valve 91, while the screw portion connected to the crosshead 94 is in the atmosphere, and the temperature is determined by heat conduction.

In this embodiment, as shown in detail in FIG. 26 for the threaded connection portion of the valve rod, the region V below the valve rod has a high creep rupture strength at high temperature, and is resistant to oxidation and bending in steam (high temperature creep). Strong materials such as 12Cr steel (SUH616), SUH660, Inconel 901, Ni
It is composed of nonic 80A and the like.

The area U of the threaded portion is 12Cr steel, SUS43, which has fatigue strength and stress corrosion resistance under high stress.
0, NINONIC 90 and the like.

Then, a region W between the region U and the region V
Is composed of a functionally graded material in which the composition ratio of both materials changes in a graded manner.

According to the structure of this embodiment, the side exposed to high temperature steam has high creep rupture strength and good steam oxidation resistance and creep resistance, while the screw side connected to the drive mechanism is Since a material having a high fatigue strength even in a corrosive environment and having a notch resistance is used and a functionally graded material is used between both parts, the valve rod 23 itself has high temperature strength and high fatigue strength in a corrosive environment. You will have a match.

Therefore, the portion 93c of the valve rod 93 exposed to the high temperature and high pressure steam is strong against high stress, and the portion 93b in the intermediate bush has a fast oxidation film growth due to the steam oxidation resistance.
The sliding of the valve rod 93 is secured, and the fatigue strength of the threaded portion 93a is secured in a corrosive environment. Therefore, the factor that causes breakage of the valve rod 93 is suppressed, and the valve rod life is extended to improve reliability and safety. The property is improved.

Further, since the valve rod 93 is formed by using the functionally graded material having no clear boundary, the portion 93 having a high temperature is formed.
c is an austenitic heat-resistant steel, and the screw portion 93a is a ferritic or martensitic corrosion-resistant material, so that there is no restriction on the material combination, and the thermal stress caused by the difference in elongation due to the difference in linear expansion coefficient is reduced. Is possible. Therefore, the valve rod itself can be provided with high-temperature rupture strength without peeling or cracking from the boundary of material composition during operation, and also has high fatigue strength in a corrosive environment. As a result, the fatigue strength is reduced due to pitting corrosion that occurs in a corrosive environment, and sulfides in the anti-seizure agent of the screw portion, fluoride, etc. have sufficient strength against stress corrosion cracking, It is safe to drive.

[0117]

As described above, according to the first aspect of the invention, the material of the bearing metal on the side receiving the shaft has good lubricating characteristics,
A porous material containing lubricating oil or a material with a small coefficient of friction is used, and the opposite side is made of a material that has sufficient strength to support the load from the shaft, and the middle part is a functionally graded material. The bearing has sufficient strength at the same time as the lubrication characteristics, and the reliability of the bearing can be improved without causing peeling or the like.

According to the invention of claim 2, in the cat foot of the high and medium pressure turbine casing, the key can be prevented from being damaged by the frictional force due to the thermal expansion at the time of starting and stopping the turbine, and the reliability and safety are greatly improved. Can be made.

According to the invention of claim 3, a steam turbine,
Even if there is a contact between the rotor and the radial seal fin of the shaft seal device of an axial fluid machine such as a gas turbine or an axial compressor, it is possible to prevent excessive rotor vibration from occurring at the same time as well as contact friction. It is possible to prevent the phenomenon that the rotor bends and the shaft vibration is further promoted. Due to these effects, when assembling the axial fluid machine, the gap between the rotor and the radial seal fin is set to be smaller than the planned value, and the leakage fluid is reduced due to wear of the tip of the radial seal fin due to extremely slight contact, which is optimal for performance. It is possible to form a gap, which has an excellent effect of contributing to performance improvement.

According to the fourth aspect of the present invention, even if the fluid differential pressure becomes large in the gap between the stationary portion and the rotor and the gap becomes small, and the fin segments should come into contact with each other, the moving blades are not damaged. Turbine operation is possible, and reliability and safety can be greatly improved.

According to the fifth aspect of the present invention, a material having erosion resistance is used for the portion on the inlet dorsal side that is easily eroded by water droplets on the blades, and the other portions that are not eroded are subjected to centrifugal force acting during operation. The blade material itself has erosion resistance because a material capable of withstanding steam and steam power is used and a functionally graded material is used between them. Therefore, it is not necessary to attach the erosion shield plate or flame-harden the base material to increase the erosion resistance, and it is possible to prevent the flaking of the erosion shield plate and the decrease in fatigue strength due to it, which can reduce the reliability and safety of the blade. It is possible to improve the property.

According to the sixth aspect of the present invention, the side of the valve rod exposed to the high temperature and high pressure steam is resistant to high stress, and the portion in the intermediate bush has a rapid oxidation film growth due to the steam oxidation resistance. Since sliding is ensured and the threaded portion is ensured to have fatigue strength in a corrosive environment, factors that cause breakage of the valve stem are suppressed, and the life of the valve stem is extended to improve reliability and safety. In addition, since the functionally graded material does not have a clear boundary, there is no restriction on the material combination such as austenitic heat-resistant steel for the high temperature part and ferritic or martensitic corrosion resistant material for the screw part, and there is no restriction on the material combination, and the linear expansion It is possible to reduce the thermal stress caused by the difference in elongation due to the difference in coefficient.

[Brief description of drawings]

FIG. 1 is an overall sectional view showing a configuration of a first embodiment.

FIG. 2 is a diagram showing a bearing structure according to the embodiment.

FIG. 3 is an enlarged view of the bearing metal shown in FIG.

FIG. 4 is a diagram showing another bearing structure in the example.

5 is an enlarged view of the bearing metal shown in FIG.

FIG. 6 is a view showing still another bearing structure according to the embodiment.

FIG. 7 is an enlarged view of the bearing metal in FIG.

FIG. 8 is an overall sectional view showing a configuration of a second embodiment.

9 is a diagram showing a cat foot portion of the steam turbine shown in FIG. 2. FIG.

10 is a cross-sectional view taken along line XX of FIG.

11 is a diagram showing the keys of FIG. 10. FIG.

12 is a sectional view taken along line XII-XII in FIG.

FIG. 13 is a diagram showing the keys of FIG. 12;

FIG. 14 is a cross-sectional view showing a third embodiment.

15 is a sectional view taken along line XV-XV in FIG.

16 is an enlarged view showing a part of FIG.

FIG. 17 is a cross-sectional view showing a fourth embodiment.

FIG. 18 is an enlarged view of a main part of FIG.

FIG. 19 is a plan view of the segment of FIG.

FIG. 20 is a sectional view of the segment.

FIG. 21 is a cross-sectional view showing Example 5.

FIG. 22 is an explanatory view of the operation of the embodiment.

FIG. 23 is a view showing the blade of the same embodiment.

FIG. 24 is a system diagram showing Example 6.

FIG. 25 is a view showing the valve structure of the embodiment.

FIG. 26 is a diagram showing the valve stem of FIG. 25.

[Explanation of symbols]

 2 rotating shaft 5 bearing 6, 11, 12 bearing metal 23 bearing stand 21 casing 24, 26 key 25, 27 bolt 31 rotor 33 radial seal fin 41 rotor 42 rotor blade 43 nozzle outer ring (stationary part) 44 fin segment 48 bellows 62 rotor 61 moving blade 74 steam control valve 93 valve rod

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical display location F01D 25/16 A (72) Inventor Hirofumi Mezaki 4 stock companies 2 Suehiro-cho, Tsurumi-ku, Yokohama-shi, Kanagawa Toshiba Keihin Office

Claims (6)

[Claims] 1. In a rotary machine in which a rotating shaft is supported by a bearing metal of a sliding bearing, a surface of the bearing metal that receives the rotating shaft is made of a material having good compatibility with the rotating shaft, a porous oil-impregnated bearing material, or a low-impregnated bearing material. One of the friction coefficient materials, while the other side of the rotating shaft receiving side is made of a material having sufficient strength to support a load from the rotating shaft, and a region between the two materials. The rotating machine is characterized by comprising a functionally graded material in which the ratio of both materials changes in an inclined manner. 2. A rotary machine in which a bearing base for mounting a bearing for supporting a rotary shaft and a casing for covering the rotary shaft are keyed together, and the key is fastened and fixed to the bearing base by bolts. The casing facing surface side is made of a material with excellent slidability, while the bolt fastening side of the key to the bearing stand is made of a high-strength alloy steel material, and the area between the two materials is made up of a ratio of both materials. A rotary machine characterized by being composed of a functionally graded material that changes in a slanted manner. 3. An axial flow fluid type rotation in which a plurality of radial seal fins for closing the gap are arranged at intervals in the axial direction of the rotor in a stationary portion surrounding the outer peripheral portion of the rotor with a gap. In the machine, a rotary machine characterized in that a tip side of the radial seal fin is made of a functionally graded material having a lower friction coefficient than a material of a base side thereof. 4. A fin segment for adjusting the clearance is mounted on a stationary part surrounding the outer peripheral part of the rotor blade with a clearance through an expandable bellows. In an axial flow fluid type rotary machine capable of moving the fin segment in the radial direction of the rotor by a pressure difference, the side of the fin segment facing the rotor is made of a non-ferrous material or a low hardness material, A rotary machine characterized in that the bellows mounting side of the fin segment is made of a material having good weldability, and the region between the two materials is made of a functionally graded material in which the ratio of the two materials changes in an inclined manner. 5. A rotary machine having a rotor rotatably driven by using moist steam as a working fluid, wherein the rotor blades of the rotor are arranged in an environment where erosion is caused by collision of water droplets. The steam inlet rear surface that is eroded by water droplets is made of a material having high erosion resistance, while the non-eroded portion of the moving blade is made of a material having high strength against centrifugal force or steam force acting during operation, and A rotary machine, characterized in that a region between the two materials is formed of a functionally graded material in which a ratio of the both materials changes in an inclined manner. 6. A rotary machine of axial flow type having a valve for controlling the flow of a fluid of high temperature and high pressure, the valve of a valve rod connecting the valve and a drive mechanism for driving the valve. On the other hand, the connecting side with is made of a material having high temperature creep rupture strength, while the side connected to the drive mechanism is made of a material having high fatigue strength due to stress amplitude and strong against stress corrosion, and between the two materials. A rotary machine characterized in that the region is composed of a functionally graded material in which the ratio of both materials changes in a graded manner.