JPH08218810A - Rotor supporting jig for steam turbine - Google Patents

Abstract

PURPOSE: To stably hang and support a rotor as weight without damaging a journal surface of a main shaft. CONSTITUTION: A rotor supporting jig afloats a rotor from a main bearing at the inspection of a steam turbine and rotatably supports it. The jig is composed of a hanging frame 5 to be installed on a bearing base 2 from which an upper cover is demounted, and a half ring 7 being hung from an end of a stud bolt 6 installed on the frame for surrounding a main shaft 1 of the rotor from the lower side. A sliding pad 12 divided into plural segments each having a sliding surface with the rotor main shaft 1 coated with material having small surface frictional resistance such as fuluororesin is formed on an inner peripheral surface of the half ring. The main shaft of the rotor is mounted on the sliding pad at the inspection of the steam turbine, and the half ring is pulled up, and the rotor is floated from the main bearing for hanging.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotor support jig that floats a rotor from a main bearing and rotatably supports the rotor during inspection of a steam turbine.

[0002]

2. Description of the Related Art When inspecting the surface condition of the bearing metal of the main bearing (journal bearing) of a steam turbine and the rotor blades in an assembly plant or at the installation site, a rotor support jig is mounted on the bearing stand. A tool is temporarily installed, and the rotor is temporarily levitated from the main bearing by this supporting jig so as to be supported in a rotatable state.

Next, the structure of a conventional rotor supporting jig is shown in FIGS. 3 (a) and 3 (b). In the figure, 1 is a rotor main shaft of a steam turbine, 2 is a bearing stand with an upper cover removed, and 3 is a rotor support jig. Here, the rotor support jig 3 is placed on the bearing stand 2 (on the flange surface of the bearing stand that is axially displaced from the installation location of the bearing metal) and is fastened in place with the fixing bolts 4. U-shaped suspension frame 5 and a pair of left and right stud bolts 6 attached to the frame 5.
And a half ring 7 suspended and supported at the tip of the stud bolt 6 as main components, and a large number of needle-shaped rollers (made of metal) 8a are formed on the inner peripheral surface of the half ring 7 as a flat surface. A needle bearing 8 called a flat package arranged above is laid and fixed to the half ring 7 with a set screw 8b. 9 is a stud bolt 6
An adjustment nut 10 screwed into the shaft 10 is a thrust bearing interposed between the adjustment nut 9 and the upper surface of the pedestal 5, and 11 is a fine adjustment screw for moving the half ring 7 in the left-right direction so as to match the center position.

The rotor supporting jig 3 having such a structure is used as follows. Upper casing of steam turbine,
With the upper covers of the main shaft bearing bases arranged at both ends of the rotor main shaft 1 removed, first, the suspension base 5 is set at a predetermined position at the upper end of the main shaft base (a position away from the bearing metal), and then the half mounts are set. The ring 7 is inserted into the gap between the main shaft 1 and the bearing stand 2 so as to hold the journal portion of the main shaft 1 from below, and is connected to the stud bolt 6. In this state, the adjusting nut 9 is then rotated to pull up the half ring 7 together with the stud bolt 6, and the main shaft 1 of the rotor is supported by the half ring 7 via the needle bearing 8, while the entire rotor is slightly moved from the bearing. Lift to the floating position. Further, the fine adjustment screw 11 is operated to perform axial alignment so that the rotor is correctly positioned at the center.

Then, the following inspection is carried out with the rotor suspended. 1) Remove the bearing metal of the main bearing and inspect it for damage. 2) While slowly rotating the rotor, inspect the entire surface of the rotor, including the journal surface of the main shaft 1 and the rotor blades for abnormalities. When the inspection is completed, the bearing metal is attached to the bearing base 2 and the half ring 7 is operated by operating the stud bolt 6.
At the same time, the rotor is hung on the main bearing, and then the jig 3 is removed.

[0006]

By the way, the following problems remain in the structure of the conventional rotor supporting jig described above. That is, since the rotor of a medium-sized steam turbine having a capacity of about 100,000 kW is relatively light in weight (about 20 tons), there is no particular problem. Since it exceeds 50 tons, the needle bearing 8a of the needle bearing 8 laid on the inner peripheral surface of the half ring 7 becomes insufficient in yield strength, and the hertz between the needle roller 8a and the spindle 1 is further reduced. The surface pressure applied to the surface of the journal portion of the spindle 1 locally exceeds the allowable value due to the contact, which may cause scratches on the surface of the journal.

The present invention has been made in view of the above points, and an object thereof is to solve the above problems and to safely suspend and support a heavy rotor without damaging the surface of its spindle journal. An object is to provide a jig for supporting a rotor of a steam turbine improved as much as possible.

[0008]

In order to achieve the above object, according to the constitution of the present invention, a material having a small surface friction resistance is formed on the inner peripheral surface of the half ring combined with the suspension base and the stud bolt. A sliding pad covering the sliding surface with the rotor main shaft shall be laid. Further, the sliding pad is constituted by an arc-shaped plate whose surface is coated with a fluorine resin, and the sliding pad may be divided into a plurality of segments and dispersedly arranged on the inner peripheral surface of the half ring. it can.

[0009]

By laying the sliding pad having the above structure on the inner peripheral surface of the half ring facing the journal portion of the rotor spindle, the journal and the sliding pad are in surface contact with each other while the rotor is supported. Therefore, the surface pressure applied between the two becomes low, and since the fluorine resin coated on the surface of the pad has a hardness smaller than that of the metal material of the rotor spindle, the surface of the journal is not likely to be damaged. Also, fluororesin has a very low surface friction resistance and is slippery,
By applying a light force from the outside, the rotor can be easily rotated while being supported on the half ring.

Although one sliding pad can cover the entire inner peripheral surface of the half ring, the sliding pad can be divided into a plurality of segments and installed on the inner peripheral surface of the half ring. Easy installation and replacement of parts.

[0011]

Embodiments of the present invention will be described below with reference to FIGS. In the drawings of the embodiments, the same members corresponding to FIG. 3 are designated by the same reference numerals. In FIG. 1, the rotor support jig 3 has basically the same configuration as the conventional jig shown in FIG. The sliding pad 12 is divided into a plurality of segments (three in the illustrated example) and distributed. The sliding pad 12 is a steel plate having a thickness of several mm formed in an arc shape according to the curvature of the half ring 7 as a substrate 12a, and a fluororesin (polytetrafluoroethylene (P
TFE)) 12b film is coated and formed by adhesion, and is fixed to the half ring 7 with a set screw 13 so that the screw head does not protrude from the fluororesin surface. It should be noted that instead of the fluororesin, another material such as a resin having a small surface frictional resistance may be adopted for implementation.

[0012]

As described above, according to the structure of the present invention, the rotor main shaft is made of a material such as fluororesin having a small surface friction resistance on the inner peripheral surface of the half ring combined with the suspension base and the stud bolt. By laying the sliding pad that covers the sliding surface, the surface pressure applied between the journal part of the main shaft and the sliding pad while supporting the rotor is lower than that of the conventional structure with the needle bearing. With
In particular, since the fluorine resin coated on the surface of the pad has a hardness lower than that of the metal material of the rotor spindle, there is no risk of scratching the surface of the journal of the spindle. The surface of the journal can be safely supported without being scratched, improving reliability. In addition, the fluororesin has a very low surface friction resistance and is slippery, and the rotor can be easily rotated while being supported on the half ring by applying a light force from the outside. To be

[Brief description of drawings]

FIG. 1 is a front cross-sectional view showing an assembled configuration of a working example of the present invention.

FIG. 2 is a structural diagram of the half ring in FIG.
(A) is a perspective view, (b) is a sectional view taken along the line A-A of (a).

3A and 3B are assembly configuration diagrams of a conventional rotor support jig, in which FIG. 3A is a front view and FIG. 3B is a sectional view of a half ring in FIG.

[Explanation of symbols]

 1 Rotor main shaft 2 Bearing stand 3 Rotor support jig 5 Suspension stand 6 Stud bolt 7 Half ring 12 Sliding pad 12b Fluorocarbon resin 13 Set screw

Claims (3)

[Claims] 1. A rotor support jig for floating and supporting a rotor rotatably from a main bearing when inspecting a steam turbine, and a suspension mount to be mounted on a bearing base without an upper cover, and to the mount. A half ring that hangs on the tip of the attached stud bolt to hold the main shaft of the rotor from below, and a sliding surface with the main shaft journal of the rotor made of a material with small surface friction resistance on the inner peripheral surface of the half ring. A jig for supporting a rotor of a steam turbine, characterized in that a sliding pad coated with is laid. 2. A rotor support jig for a steam turbine according to claim 1, wherein the sliding pad is an arc-shaped plate whose surface is coated with fluorine resin. 3. A rotor support jig for a steam turbine according to claim 1 or 2, wherein the sliding pads are divided into a plurality of segments and are distributed on the inner peripheral surface of the half ring. Jig.