JPS59213903A - Steam turbine rotor system - Google Patents

Abstract

PURPOSE:To shorten a rotor span by directly interposing low chromium alloy steel thrust receiving parts between austenite group alloy steel or high chromium alloy steel rotors and directly connecting said adjacent rotors. CONSTITUTION:Low chromium alloy steel thrust receiving parts 22 are interposed between a high pressure rotor 1' and a medium pressure rotor 2 which are made of austenite group alloy steel or of high chrominum alloy steel, and each of the parts is fastened to the high pessure rotor 1' and the medium pressure rotor 2 by means of a bolt 10 respectively. The opposing surfaces of the thrust receiving part 22 to each other are served as the thrust receiving surfaces, and a thrust bearing 12 is fitted between these surfaces. Thus, since a thrust receiving part is directly interposed between adjacent rotors, it is not necessary to provide any coupling, enabling the rotor span to be shortened by that length.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a rotor system consisting of rotor shafts directly connected to each other on the same axis, such as a high-pressure rotor for a steam turbine and a medium-sized rotor for a steam turbine.

[Background of the invention]

With the development of reheat steam turbine technology, for example, the steam condition
High-temperature, high-pressure steam turbines have come into practical use. In this case, H material with high high-temperature strength must be used for both the high-pressure rotor and the medium-pressure rotor. Suitable materials include strong steels such as austenitic alloys or high chromium alloy steels, such as iron-based alloy A2680-ta material or 12Cr-Mo-V rotor material. If this is used, the required strength can be maintained without disk cooling, so it has the advantage of preventing heat loss due to disk cooling. However, on the other hand, this material has the disadvantage that +I4 scratches are likely to occur on the bearing surface. To overcome this drawback, it is common practice to shrink-fit a sleeve made of low-chromium steel to the bearing of a rotor made of strong austenitic alloy steel or high-chromium alloy steel. Since low-chromium steel materials are less likely to cause warping, the sliding surface can be protected by shrink-fitting a sleeve like this. Although the method of protecting the female C sliding surface can be applied to the radial direction bearing portion of the rotor, it is difficult to apply it to the thrust direction bearing portion.

Regarding the four points between this conventional technique and Tochi, an example of the conventional rotor system i.14 shown in Fig. 1 is further explained in reference 11fi L. Conventionally, for example, steam condition 24
6Kg/Cl18 g-5381566C In the primary shaft for a fake steam turbine, the medium-pressure rotor is made of high-chromium alloy-based strong steel, and the high-pressure rotor is made of low-chromium alloy-based strong I rice steel. (sliding on the bearing surface) i'i! This covers the disadvantage of occurrence. In Fig. 1, numeral 1 is a high-pressure rotor made of low chromium alloy ICr-Mo-V steel, which does not easily cause sliding contact, and 2 is a high-pressure rotor made of high-pressure rotor 6
12Cr-Mo-VM, a high chromium alloy with strong emotional strength
This is a medium pressure rotor made by Since the high-pressure rotor 1 is made of a material that does not easily cause friction damage, it is easy to
There is no radial support between the bearing 3 and the second bearing 4. However, since the medium-pressure rotor 2 is made of a material that easily causes sliding damage, a sleeve-shaped shrink-fit journal 5.5 is fixed and its outer periphery is supported in the radial direction by the third bearing 6 and the 41st relo bearing 7. ing. Then, a machined coupling 8 made integrally with the high-pressure rotor 1 and a shrink-fit coupling 9 installed on the offer rotor 2 are fastened with bolts 10 to directly connect both rotors. Furthermore, in order to position the rotor thread in the thrust direction, a pair of seven-lunge-shaped thrust bearings form a portion 11.degree. 11 on the high-pressure rotor 1, and the thrust bearing 12 is opposed to this. In this case, since the high-pressure rotor 1 is made of a material that does not easily cause sliding damage, if an appropriate slippage is provided, even if it comes into sliding contact with the thrust bearing 12, no problem will arise in separate installation. 13 is the rotor of the generator, and a machined coupling 1 is attached to one end of the rotor.
4 is formed. A ring gear 16 for turning is interposed between the shaved comp ring 14 and a shrink-fit coupling 15 fixed to the medium pressure rotor 2.
It was concluded in 7. 18 and 18' are rotor blades provided on the high pressure rotor 1 and the intermediate pressure rotor 2, respectively.

However, as mentioned above, with the recent advances in turbine technology, research has been conducted to increase the main steam temperature to a high temperature of 560C or higher. However, if both the high-pressure rotor and the intermediate-pressure rotor are made of austenitic alloy or high-chromium strong steel according to this point 16, the thrust receiver will have to take measures against scratches on the surface. This is the biggest technical bottleneck.In other words, to protect the bearing surface in the radial direction, a sleeve-shaped shrink-fit journal can be provided as in the conventional method described above, but this method protects the bearing surface in the thrust direction. For this reason, conventionally, if both the normal pressure rotor and the intermediate pressure rotor were made of austenite alloy system or high chromium system strong steel, it was not possible to provide a thrust/oil pan near the connection between the two rotors. It was considered impossible.

On the other hand, recently, a structure as shown in FIG. 2 has been proposed. The structural example shown in Figure 2 is the reference line x
The portion to the right of -x', ie, the intermediate pressure rotor 2 and its attached members, is the same as the conventional device shown in FIG. The high-pressure rotor 1' is made of 12Cr-Mo-V, which is a high-chromium alloy-based strong steel, and has shrink-fit journals 5', 5' fitted into its journals, and a first bearing 3', a first bearing 3', and a first bearing 3'. It is supported by two bearings 4'.

In this structural example, an intermediate rotor 19 made of lCr-Mo-V cap, which is a low-chromium alloy-based strong steel that does not easily cause seizure, is provided, and this intermediate rotor 19 is connected to a high-pressure rotor 1' and an intermediate-pressure rotor 2. A thrust bearing 12 is provided in the vicinity of the central portion of the bearing 12, which is interposed and fixed coaxially therebetween. Further, as a means for interposing and fixing the intermediate rotor 19, cut-out couplings 20 and 21 are provided at both ends thereof, and are fixed to the close-fit coupling 232 fixed to the high-pressure rotor 1' and the medium-pressure rotor 2, respectively. The shrink-fit coupling 9 is faced and fastened with bolts.
In order to provide the thrust bearing 12 in the center of the intermediate rotor 19, a pair of flange-like blood force receiving parts 22, 22 are formed near the center of the intermediate rotor, and the force receiving part is formed so that both flanges face each other. As such, a thrust bearing 12 is fitted between these both surfaces.

However, in this 1' building, as can be seen from the comparison with FIG. 1, there is a problem in that the span S of the second bearing 4' and the third bearing 6 is longer than the conventional one. When the span S becomes longer in this way, equipment costs increase and, in addition, a fire is generated which may become a cause of unstable vibration.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned problems.In a rotor system for a steam turbine in which rotors arranged on the same axis are directly connected, both of the two rotors to be directly connected or one At least one of the rotors is made of high-temperature strength austenitic alloy or high-chromium tough steel, and a highly durable thrust bearing is installed near the joint of both rotors. It is an object of the present invention to provide an advantageous steam turbine rotor system in which the length of the rotor is not increased.

[Summary of the invention]

In order to achieve the above object, the present invention provides a steam turbine rotor system in which adjacent rotors arranged on the same axis are directly connected to each other. The rotor system is made of austenitic alloy steel or high chromium alloy steel, or one rotor of the rotor system is made of austenitic alloy steel and the other rotor is made of high chromium alloy steel, and the rotor system is made of low chromium alloy steel. The thrust receiver made of alloy steel is constructed so that the parts are directly interposed, thereby making it possible to shorten the width of the lower slot.

[Embodiments of the invention]

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

FIG. 3 VC shows a first embodiment of the invention. This figure (t
Yo, 2nd IIIIII Uke 4' and 3rd 'IjIll Uke 6
An illustration is provided between the two. In this embodiment, the portion to the right of the third bearing 6, that is, the intermediate pressure rotor 2 and the members attached thereto, are the same as those in the conventional device shown in FIG. 1.

The high-pressure rotor 1' of this embodiment is made of 12Cr-Mo-V, which is a high-chromium alloy strong steel. A shrink-fit journal 5' is fitted into the journal portion and supported by a second bearing 4'.

In this embodiment, the thrust receiver made of ICr-Mo-V@tf4, which is a low-chromium strong steel, is provided with a section 22, which is connected to the high-pressure rotor 1' and the intermediate-pressure rotor 2. The plates are directly connected to the rotor and the thrust receiver with bolts 10.

This thrust bearing is a part 22, and the thrust bearing has a curved surface where both seven flange-shaped parts face each other, and the thrust bearing 12 is fitted between these surfaces. By doing this, the span S shown in FIG. 2 is shortened by the length of the coupling in this embodiment. That is, the length a shown in FIG.
b can be shortened by b - a.

In this example, a low chromium alloy steel containing 1% chromium was used, but one containing 2.5% chromium can also be effectively used. In addition, an alloy having a Cr content within a range that does not easily cause seizure may be used.

Next, referring to FIG. 4, a second embodiment of the present invention will be described. In the practical example H2 explained in FIG. 3, the fastening bolt 10 is a stud bolt, but in this example, a through bolt is used as the bolt 10 as shown in FIG. 4. That is, in the example shown in FIG. 4, since one stud bolt is used as the bolt 10, the threaded portion becomes long and the thrust receiver portion 22 also becomes thick. On the other hand, in this example,
The bolt 10 is a through bolt, and the bearing spacing is further shortened. However, in this case, since the nut also comes to the thrust bearing 12 side, it is necessary to add 6 to the nut portion.

The detailed JS construction of this part is shown in Figure 5, which is an enlarged view of part A in Figure 4.
The diagram is explained as follows.

The shrink fit coupling 9 and the thrust bearing part 22 are connected to the bolt 10.
By inserting a through bolt (through bolt), it is fastened with a nut 24 as shown in FIG. This nut 24 is screwed into the seated P hole, and the cover 25eiMi force receiver is further shrink-fitted to the part 22.

With this configuration, the surface of the thrust receiver becomes uniform as described above, and it blends in with the liliro receiver 26<;! The thrust surface becomes J4h. Of course, journal bearings and thrust
The present invention can also be applied to a thrust bearing with the same oil bearing 12.

The effects of the two embodiments described above are as follows. That is, in these rotor systems with the same implementation, both the high-pressure rotor 1' and the intermediate-pressure rotor 2 are made of high-chromium alloy-based strong steel 120r-Mo-■, so
It has sufficient high temperature strength and toughness even when operated with high temperature steam of about 6C. The thrust bearing part 22 that is in sliding contact with the thrust bearing 12 is made of a strong @lCr-Mo low chromium alloy.
Since it is made of -■, it exhibits sufficient durability if properly rubbed, and there is little risk of scratches.

The efficiency of these rotor systems is also improved due to the sufficient high-temperature strength and toughness of the rotors 1' and 2, and the sufficient durability of the thrust bearing portion 22 and the absence of scratches. It is something. For example, using the conventional rotor system shown in Fig. 1, the steam condition is 246 kg/cII-g.
-9/cr for steam condition 246 using the embodiment of the invention shown in FIGS. -g -5661566, an efficiency improvement of 0.9% was obtained.

In each of the above-mentioned embodiments, the thrust bearing 12 is provided near the joining part of both rotors, so the thrust bearing 12 is not an idiot that can reduce the risk of scratches due to the material.
This has the effect that positioning in the thrust direction can be performed.

〔Effect of the invention〕

As described above, in the present invention, both or at least one of the two rotors to be arranged on the same axis and directly connected are made of ausbunite single metal type or chromium type strong steel, so that sufficient high temperature strength can be obtained. A 71M force receiver is provided near the joint between both rotors to increase durability, and this 1ffl force receiver is directly interposed between the rotors.
・It has the effect of shortening the span between oil pans.

It should be noted that, as a matter of course, the present invention is not limited to the illustrated embodiment.

[Brief explanation of drawings]

FIG. 1 is a top view of a conventional steam turbine rotor system. Figure 2 shows an example of a proposed measure to prevent seizure when the thrust is 1. FIG. 3 is a partially cross-sectional side view of the main part of the first embodiment of the present invention. FIG. 4 is a partially cross-sectional side view of the main part of the second embodiment of the present invention, and an enlarged view of section A in FIG. 5 f'i. 1'...High pressure rotor, 2...Offer rotor, 3.3'
...First bearing, 4.4'...Second bearing, 5.5'
...shrink fit journal, 6...No. 3 IIIil]
Reception, 7...4th qlt+Reception, 10...Volt, 1
2... Thrust bearing, 22... Thrust bearing is part, S.
...Lotuspan. 'As mouth

Claims (1)

[Claims] 1. In a steam turbine rotor system in which adjacent rotors arranged on the same axis are directly connected, both rotors of the adjacent rotors in the rotor system are made of an austenitic alloy. steel or high chromium single piece steel, or one rotor of the rotor system is made of austenitic alloy copper,
The other rotor is made of high chromium alloy steel rotor material, and a thrust receiver made of low chromium alloy steel that does not easily cause seizure is directly interposed between the rotors, thereby shortening the rotor span. A steam turbine rotor system that is characterized by making it possible. 2. A steam turbine rotor system according to claim 1, characterized in that both rotors and the thrust receiver are fastened together with stud bolts. 3. A steam turbine rotor system according to claim 1, characterized in that both rotors and the thrust receiver are of a 4-quad construction in which both rotors and the thrust receiver are fastened together with double threaded bolts.