Turbine chamber, gas turbine, and alignment method

Abstract

A turbine casing is provided, which is divided into a first shell and a second shell connected by flanges in the axial direction, and the first shell and the second shell are divided into two parts, an upper half shell and a lower half shell, respectively, when viewed from the axial direction, wherein the turbine casing has three or more groups of first radial reference surfaces provided on the outer peripheral portion of the flange of the first shell and second radial reference surfaces provided on the outer peripheral portion of the flange of the second shell in the circumferential direction, each first radial reference surface is located at an equal distance from the center axis of the turbine, each second radial reference surface is located at an equal distance from the center axis of the turbine, and the turbine casing is configured so that the positional relationship between the first radial reference surface and the second radial reference surface is equal in each group. Thus, a dedicated alignment jig is not required and the time for assembling a single piece is shortened.

Description

Technical Field

[0001] The invention relates to a turbine chamber, a gas turbine and an alignment method. Background Art

[0002] For example, a gas turbine includes a compressor that generates compressed air, a combustor that mixes fuel with the compressed air and burns it to generate combustion gas, and a turbine driven by the combustion gas. The turbine casing constituting the outer contour of the gas turbine is usually divided into a plurality of parts in the axial direction (Patent Document 1).

[0003] Prior Art Literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2013-181503

[0006] When assembling a gas turbine, a single-piece assembly of only the turbine chamber is performed before the final assembly by assembling the rotor inside. In this single-piece assembly process, the axial alignment (center alignment) of each component is performed with the turbine chamber standing vertically. In the axial alignment operation, an alignment jig is sometimes used in which a dial indicator is mounted on an arm that rotates around a pole. Specifically, the component is placed in a manner covering the pole, the arm is rotated around the pole, and the distance between the pole and the inner circumference of the component is measured using a dial indicator, and the position of the component is adjusted in the horizontal direction so that the entire circumference of the inner circumference is equidistant from the pole. By performing this operation on all the stacked components each time, the axes of the components are aligned with each other based on the pole.

[0007] However, this operation takes time and requires preparation of a dedicated alignment jig. Summary of the invention

[0008] An object of the present invention is to provide a turbine casing, a gas turbine, and an alignment method that do not require a dedicated alignment jig and can shorten the time for assembling a single piece.

[0009] In order to achieve the above-mentioned purpose, the present invention provides a turbine chamber, which is axially divided into the first shell and the second shell connected by each other's flanges, and the first shell and the second shell are respectively divided into two parts, an upper half shell and a lower half shell, when viewed from the axial direction, wherein the turbine chamber has more than three groups of first radial reference surfaces arranged on the flange outer peripheral portion of the first shell and second radial reference surfaces arranged on the flange outer peripheral portion of the second shell in the circumferential direction, each first radial reference surface is located at a position equidistant from the center axis of the turbine, and each second radial reference surface is located at a position equidistant from the center axis of the turbine, and the turbine chamber is constructed so that the positional relationship between the first radial reference surface and the second radial reference surface is equal in each group.

[0010] Effects of the Invention

[0011] According to the present invention, a dedicated alignment jig is not required, and the time for assembling a single piece can be shortened. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic configuration diagram of an example of a gas turbine according to an embodiment of the present invention.

[0013] Figure 2 This is a diagram showing a first casing and a second casing constituting a turbine casing of a gas turbine according to an embodiment of the present invention, which are extracted.

[0014] Figure 3 yes Figure 2 Cross-sectional view along line III-III.

[0015] Figure 4 yes Figure 2 An enlarged view of the portion indicated by arrow IV.

[0016] Figure 5 yes Figure 3 Cross-sectional view along line VV in FIG.

[0017] Description of reference numerals:

[0018] 21...combustor casing (second casing); 1C...second tilt reference plane; 21L...lower casing; 21R...second radial reference plane; 21U...upper casing; 21v...flange; 21x...slit; 21y...cut; 31...turbine casing (first casing); 31C...first tilt reference plane; 31L...lower casing; 31R...first radial reference plane; 31U...upper casing; 31v...flange; 31x...slit; 31y...cut; 41...through hole; 43...locating pin; 44...bushing; dR...height difference (positional relationship between the first radial reference plane and the second radial reference plane); R1...distance between the first radial reference plane and the central axis of the turbine; R2...distance between the second radial reference plane and the central axis of the turbine. DETAILED DESCRIPTION

[0019] Hereinafter, embodiments of the present invention will be described using the drawings.

[0020] -gas turbine-

[0021] Figure 1 This is a schematic structural diagram of an example of a gas turbine according to an embodiment of the present invention. The gas turbine shown in the figure is a prime mover that drives a load device (not shown), and includes a compressor 10, a combustor 20, a turbine 30, and an exhaust chamber 35. The casing of the compressor 10 (compressor casing 11) is supported by a leg 12, the casing of the turbine 30 (turbine casing 31) is supported by a leg 32, and the exhaust chamber 35 is supported by a leg 38. The load device is typically a generator, but a pump is sometimes used. It should be noted that when a gas turbine is referred to as a "gas turbine engine", the turbine is sometimes referred to as a "gas turbine".

[0022] The compressor 10 has an air intake port 13 for taking in air, and an inlet guide vane (IGV: Inlet Guide Vane) 14 in the compressor housing 11, and has a stage section in which stationary blades 15 and moving blades 16 are alternately arranged in the direction of the turbine center axis after the inlet guide vane 14. A plurality of combustors 20 are arranged in an annular shape on the outer periphery of the combustor housing 21 between the compressor 10 and the turbine 30. The turbine 30 has stationary blades 33 and moving blades 34 alternately arranged in the turbine center axis direction in the turbine housing 31. An exhaust chamber 35 is arranged on the downstream side of the turbine housing 31 via an exhaust housing 36. The exhaust chamber 35 has an exhaust diffuser 37 continuous with the turbine 30.

[0023] The rotor 5 is arranged so as to pass through the center of the compressor 10, the combustor 20, the turbine 30, and the exhaust chamber 35. The end of the rotor 5 on the compressor 10 side is rotatably supported by the bearing 6, and the end on the exhaust chamber 35 side is rotatably supported by the bearing 7. The portion of the rotor 5 belonging to the compressor 10 is formed by axially overlapping a plurality of blades equipped with a plurality of moving blades 16 on the outer periphery. The portion of the rotor 5 belonging to the turbine 30 is formed by axially overlapping a plurality of blades equipped with a plurality of moving blades 34 on the outer periphery. Figure 1 In the example, the end of the rotor 5 on the exhaust chamber 35 side is connected to the drive shaft of the load device (not shown) as an output shaft.

[0024] In the above structure, the air taken into the compressor 10 from the air intake 13 is compressed by the inlet guide vanes 14, the cascade of the stationary blades 15, and the cascade of the moving blades 16, generating high-temperature and high-pressure compressed air. In the combustor 20, the fuel supplied from the fuel system is mixed with the compressed air supplied from the compressor 10 and burned, generating high-temperature combustion gas and supplying it to the turbine 30. The fuel uses liquid fuel or gas fuel. The high-temperature and high-pressure combustion gas, which is the working fluid generated by the combustor 20, passes through the cascade of the stationary blades 33 and the cascade of the moving blades 34 in the turbine 30, thereby driving the rotor 5 to rotate. A part of the output of the turbine 30 is used as the power of the compressor 10, and the remaining part is used as the power of the load device 4. The combustion gas after driving the turbine 30 is discharged as exhaust gas through the exhaust chamber 35. In this embodiment, a single-shaft gas turbine is exemplified, but the invention also includes a dual-shaft gas turbine. The twin-shaft gas turbine includes a high-pressure turbine and a low-pressure turbine whose rotating shafts are separated from each other, and the high-pressure turbine is coaxially connected to the compressor, and the low-pressure turbine is coaxially connected to the turbine.

[0025] -Turbine room-

[0026] The gas turbine has a turbine housing that accommodates a rotor 5. The turbine housing is divided into a plurality of divided casings as cylindrical components in the turbine center axis direction, specifically, a compressor casing 11, a combustor casing 21, a turbine casing 31, an exhaust casing 36, etc. The compressor casing 11 and the combustor casing 21 have vertical annular flanges (for example, at the ends of the casings) at the opposing portions. Figure 2 The flanges 21v, 31v, etc. described later in the drawing are fastened and connected by bolts (not shown). The same applies to the combustor casing 21 and the turbine casing 31. The same applies to the turbine casing 31 and the exhaust casing 36. In addition, the number of axial divisions of the turbine casing can be changed.

[0027] Furthermore, each component of the turbine housing, such as the compressor housing 11, the combustor housing 21, the turbine housing 31, and the exhaust housing 36, is divided into two parts, an upper half housing and a lower half housing, when viewed from the axial direction. Each upper half housing and the corresponding lower half housing have horizontally extending flanges (for example, at the Figure 2 The flanges 21h1, 21h2, 31h1, 31h2, etc. described later) are connected by fastening these flanges with a plurality of bolts (not shown).

[0028] - Alignment Structure -

[0029] Figure 2 This is a diagram showing the first casing and the second casing constituting the turbine chamber extracted. Figure 3 yes Figure 2 The cross-sectional view of line III-III in the figure, Figure 4 Is Figure 2 The enlarged view of the part shown by arrow IV, Figure 5 yes Figure 3 In the assembly of the gas turbine, the rotor 5 ( Figure 1 ) is assembled into the turbine housing before the final assembly. Figure 2-Figure 5 , the situation when the first housing and the second housing are aligned in the single-piece assembly of the turbine casing is simulated. Specifically, the state in which the second housing is stacked on the first housing with the turbine center axis set vertically is shown.

[0030] In this specification, components of the turbine casing that are adjacent to each other in the turbine axial direction and connected by flanges to each other are appropriately described as a first casing and a second casing. Figure 2 In FIG. 1 , the turbine housing 31 and the combustor housing 21 are exemplified as the first housing and the second housing. In addition, the exhaust housing 36 and the turbine housing 31, and the combustor housing 21 and the compressor housing 11 also correspond to the first housing and the second housing. In addition, the objects of the first housing and the second housing may be reversed.

[0031] In the turbine housing, three or more (in this example, four) radial reference surface groups are provided at intervals in the circumferential direction at the opposing portions of the first housing (here, the turbine housing 31) and the second housing (the combustor housing 21). Each group of radial reference surfaces is composed of a first radial reference surface 31R ( Figure 3 , Figure 5 ) and a second radial reference surface 21R ( Figure 5 )constitute.

[0032] The first radial reference surfaces 31R are located at positions that are all equidistant from the turbine center axis (positions at a distance R1 from the turbine center axis). In addition, each first radial reference surface 31R is formed by a surface that is parallel to the turbine center axis and faces the radial outer side of the turbine housing 31, among the inner wall surfaces of the flat groove-shaped slits 31x provided on the outer peripheral portion of the flange 31v of the turbine housing 31. In the present embodiment, the first radial reference surface 31R is a plane, and when viewed in the direction of the turbine center axis, the first radial reference surface 31R is orthogonal to a plane that includes the turbine center axis at a position at a distance R1 from the turbine center axis. That is, when viewed in the direction of the turbine center axis, the first radial reference surfaces 31R each form a tangent to the same circle centered on the turbine center axis. However, the first radial reference surface 31R does not need to be a plane, and may be, for example, a curved surface, as long as it is in a predetermined positional relationship with the second radial reference surface 21R.

[0033] The second radial reference planes 21R are located at positions that are all equidistant from the turbine center axis (positions at a distance R2 from the turbine center axis). In addition, each second radial reference plane 21R is formed by a surface that is parallel to the turbine center axis and faces the radial outer side of the combustor housing 21, among the inner wall surfaces of the flat groove-shaped slits 21x provided on the outer peripheral portion of the flange 21v of the combustor housing 21. In the present embodiment, the second radial reference plane 21R is a plane, and when viewed in the direction of the turbine center axis, the second radial reference plane 21R is orthogonal to a plane that includes the turbine center axis at a position at a distance R2 from the turbine center axis. That is, when viewed in the direction of the turbine center axis, the second radial reference planes 21R each form a tangent to the same circle centered on the turbine center axis. However, the second radial reference plane 21R does not need to be a plane, and may be a curved surface, for example, as long as it is in a predetermined positional relationship with the first radial reference plane 31R.

[0034] The positional relationship between the first radial reference surface 31R and the second radial reference surface 21R is configured to be equal in each group of the first and second reference surfaces. The first radial reference surface 31R and the second radial reference surface 21R may also be the same plane (that is, R1 = R2), but as long as the positional relationship between them is equal in each group, they do not necessarily have to be the same plane. Figure 5 In FIG. 1 , an example is shown in which the second radial reference surface 21R is separated from the first radial reference surface 31R by a distance dR relative to the turbine center axis, and a height difference exists between the radial reference surfaces 31R and 21R.

[0035] In addition, if Figure 4 As shown, in the turbine casing, at least one set (two sets at 180° intervals in this example) of groove-shaped cutouts 31y, 21y are provided in the opposing portions of the first casing (turbine casing 31) and the second casing (combustor casing 21).

[0036] The cutout 31y is formed on one side (at the bottom) of the upper half shell 31U and the lower half shell 31L of the turbine shell 31. Figure 4 The lower half shell 31L in the middle is provided in a manner opposite to the other side (upper half shell 31U). That is, the notch 31y is provided at the corner portion where the end faces of the flanges 31v and 31h2 of the turbine housing 31 intersect. The opposing surface of the upper half shell 31U that is opposite to the lower half shell 31L (that is, the end face of the flange 31h1 of the upper half shell 31U) faces the notch 31y in a partially exposed manner. The end face of the flange 31h1 facing the notch 31y constitutes a first tilt reference plane 31C for circumferential alignment of the turbine housing 31 and the combustor housing 21. Therefore, the first tilt reference plane 31C corresponds to the cross section of the flange 31v in the end face portion of the flange 31h1 of the upper half shell 31U of the turbine housing 31.

[0037] The cutout 21y is provided on one side (the lower half shell 21L in this example) of the upper half shell 21U and the lower half shell 21L of the combustor housing 21 so as to face the other side (the upper half shell 21U). That is, the cutout 21y is provided at the corner portion where the end faces of the flanges 21v and 21h2 of the combustor housing 21 intersect. The circumferential positions of the cutouts 21y and 31y correspond to each other, and they face each other in the turbine center axis direction. In addition, the opposing surface of the upper half shell 21U that faces the lower half shell 21L (that is, the end face of the flange 21h1 of the upper half shell 21U) faces the cutout 21y in a partially exposed manner. The end face of the flange 21h1 facing the cutout 21y constitutes a second tilt reference surface 21C for circumferential alignment of the turbine housing 31 and the combustor housing 21. Therefore, the second tilt reference plane 21C corresponds to a cross section of the flange 21 v in the end surface of the flange 21 h 1 of the upper half casing 21U of the combustor casing 21 .

[0038] The first tilt reference surface 31C and the second tilt reference surface 21C are both end surfaces of the upper half shells 31U and 21U facing the lower half shells 31L and 21L, so the circumferential positions are precisely aligned when the turbine casing is assembled. The circumferential width dimensions of the cutouts 31y and 21y may be aligned, but do not necessarily need to be aligned.

[0039] In addition, if Figure 5As shown, a through hole 41 parallel to the center axis of the turbine is provided on the flange 21v of the second housing (combustor housing 21). In addition, a positioning hole 42 corresponding in position to the through hole 41 is provided on the end surface of the flange 31v of the first housing (turbine housing 31). The positioning hole 42 is a pin hole for inserting a positioning pin 43. The dimensional tolerance between the outer diameter of the positioning pin 43 and the inner diameter of the positioning hole 42 is set to be extremely small, and there is substantially no gap between the outer peripheral surface of the positioning pin 43 and the inner peripheral surface of the positioning hole 42. A portion of the positioning pin 43 is inserted into the positioning hole 42 of the flange 31v of the turbine housing 31 through the through hole 41, and the remaining portion protruding from the positioning hole 42 is located inside the through hole 41. In addition, the bushing 44 is located inside the through hole 41.

[0040] The bushing 44 is a cylindrical member that covers and fits into the positioning pin 43 to fill the gap between the positioning pin 43 and the through hole 41. The dimensional tolerance between the outer diameter of the positioning pin 43 and the inner diameter of the bushing 44 is set to be extremely small, and there is substantially no gap between the outer peripheral surface of the positioning pin 43 and the inner peripheral surface of the bushing 44. Figure 5 Although not shown in the schematic diagram of FIG. 4 , the inner diameter of the through hole 41 is set to be slightly larger than the outer diameter of the bushing 44, and a predetermined gap exists between the inner peripheral surface of the through hole 41 and the outer peripheral surface of the bushing 44. The bushing 44 is fixed to the flange 21v (e.g., the inner wall of the through hole 41) of the combustor housing 21 by welding (welding portion 45) while the positioning pin 43 is inserted therein. Thus, the positioning pin 43 is restricted by the positioning hole 42, the bushing 44 is restricted by the positioning pin 43, the through hole 41 is restricted by the bushing 44, and the flanges 31v and 21v are restricted to each other.

[0041] It should be noted that in Figure 2-Figure 5 In the description, the structure of the opposing portion of the turbine housing 31 and the combustor housing 21 is taken as an example, but the structures of the radial reference surface, the roll reference surface, the positioning pins, etc. are also provided in the opposing portions of the other first housing and the second housing. Figure 2 In FIG. 1 , a radial reference plane X and a roll reference plane Y are shown.

[0042] - Turbine room alignment method -

[0043] use Figure 2-Figure 5The process of axially aligning and angularly aligning the first and second casings adjacent to each other in the axial direction during the single-piece assembly of the turbine casing is described below. When performing this process, the upper half casing 31U and the lower half casing 31L of the turbine casing 31 are previously connected to each other to form a cylindrical shape. The upper half casing 21U and the lower half casing 21L of the combustor casing 21 are also similar. The first radial reference surface 31R, the second radial reference surface 21R, the first tilt reference surface 31C, and the second tilt reference surface 21C described above are previously provided in these turbine casing 31 and combustor casing 21.

[0044] For example, the turbine housing 31 is machined (turned) on the inner diameter by, for example, a machining center in a state where it is formed into a cylindrical shape, but at this time, the first radial reference surface 31R (slit 31x) is formed in advance by, for example, milling at the same time (in one preparation operation). By forming each first radial reference surface 31R by the same method as the inner diameter processing, all the first radial reference surfaces 31R can be formed with high precision to be equidistant from the turbine center axis. The notch 31y and the positioning hole 42 related to the first roll reference surface 31C can be formed at the same time when the inner diameter of the turbine housing 31 is processed, but since positional accuracy is not required, they can also be machined by other processes.

[0045] Similarly, when the inner diameter of the combustor casing 21 is machined (turned), the second radial reference surface 21R (slit 21x) is formed at the same time (in one preparation operation) by, for example, milling. By forming the second radial reference surface 21R by the same method as the inner diameter machining, all the second radial reference surfaces 21R can be formed with high precision at equal distances from the turbine center axis. The notches 21y and the through holes 41 related to the second roll reference surface 21C can be formed at the same time as the inner diameter machining of the combustor casing 21, but since positional accuracy is not required, they can be machined in another process.

[0046] When the turbine casing is assembled as a single piece, the turbine casing 31 and the combustor casing 21 manufactured as described above are aligned (axial alignment and angular alignment). For example, on a horizontal plate, the combustor casing 21 is placed on the turbine casing 31 using, for example, a crane so that the flanges 31v and 21v face each other with the turbine center axis facing up and down. When the combustor casing 21 is stacked on the turbine casing 31, the circumferential positions of the slits 31x and 21x and the cutouts 31y and 21y are roughly aligned.

[0047] Next, the process of axial alignment and angular alignment of the combustor housing 21 relative to the turbine housing 31 is performed. These axial alignment and angular alignment processes are performed continuously or in parallel, and the angular alignment operation is also performed during the axial alignment. When the axial alignment and angular alignment processes are performed continuously, any one of the processes may be performed first. The axial alignment and angular alignment operations may be repeated alternately several times as needed.

[0048] First, the process of angularly aligning the combustor housing 21 with respect to the turbine housing 31 is described. In the angular alignment process, while the combustor housing 21 is lifted upward by a crane or the like, the combustor housing 21 is rotated (tilted) about the center axis by hand, for example, so that the circumferential positions of the turbine housing 31 and the combustor housing 21 are aligned. By finely adjusting the angle of the combustor housing 21 in this way, the circumferential positions of the first tilt reference surface 31C and the second tilt reference surface 21C are made consistent. As one method at this time, for example, the abutting metal member M ( Figure 4 ) and the tilt reference surface 31C or 21C (at Figure 4 Then, the contact between the metal member M and the tilt reference surface 21C or 31C (in the example of the tilt reference surface 31C) is measured by using a ruler, a gap gauge, etc. Figure 4 In the example of FIG. 2 , the combustor casing 21 is moved so that the gap G becomes 0. Thus, the angle of the combustor casing 21 relative to the turbine casing 31 can be aligned.

[0049] Next, the process of axial alignment will be described. The process of axial alignment is similar to the process of angle alignment. While the combustor casing 21 is lifted upward by a crane, the combustor casing 21 is moved (displaced) in the horizontal direction, for example, by hand, so that the center of the combustor casing 21 is aligned with the center of the turbine casing 31. By finely adjusting the horizontal position of the combustor casing 21 in this way, the positional relationship between the first radial reference plane 31R and the second radial reference plane 21R is made equal in all circumferential locations. Specifically, as the positional relationship between the first radial reference plane 31R and the second radial reference plane 21R, the height difference between the two is measured using a measuring instrument such as a micrometer, so that the height difference is equal in all circumferential locations. That is, all the height differences between the first radial reference plane 31R and the second radial reference plane 21R become relative to the distance dR ( Figure 5 ) is within the preset allowable value.

[0050] At this time, for example, if the width dimension of the slit 31x or 21x is made to match the width of the magnet stand holding the micrometer, the magnet stand is set at the slit 31x or 21x, and the positioning of the point measured by the micrometer is also easy. If the micrometer is set at each position in the circumferential direction in this way, the position of the burner casing 21 is adjusted while observing the measured value of each micrometer, the efficiency of the shaft alignment work is improved.

[0051] -Effect-

[0052] (1) As described above, when the axes of the first housing and the second housing adjacent in the axial direction are aligned, three or more sets of the first radial reference surface 31R and the second radial reference surface 21R are provided in the circumferential direction. All the first radial reference surfaces 31R are located at positions equidistant from the center axis of the turbine, and all the second radial reference surfaces 21R are located at positions equidistant from the center axis of the turbine. Therefore, as long as the positional relationship between the first radial reference surface 31R and the second radial reference surface 21R is adjusted to be equal at three or more locations, the centers of the first housing and the second housing can be geometrically aligned. Thus, according to this embodiment, a dedicated alignment jig is not required in the operation of aligning the axes of the first housing and the second housing. In addition, since the operation is easy, the operation time for aligning the axes of the first housing and the second housing can be shortened, and the time for assembling the single piece of the turbine chamber can be shortened.

[0053] (2) In theory, it is also possible to select a specific portion of the unprocessed flange as the first radial reference surface 31R and the second radial reference surface 21R. However, in this case, in addition to the flange being a high-precision perfect circle, when processing the inner diameters of the first shell and the second shell, extremely strict centering accuracy is required based on the outer diameter of the flange.

[0054] Therefore, in this embodiment, slits 31x and 21x are provided in the outer peripheral parts of the flanges of the first housing and the second housing, and the inner wall surfaces of the slits 31x and 21x are set as the first radial reference surface 31R and the second radial reference surface 21R. For example, when the inner diameters of the first housing and the second housing are processed, the slits 31x and 21x can be machined together using a machining center or the like in the same method as the inner diameter processing. As a result, the distance between each first radial reference surface 31R and the central axis of the turbine can be made to match with high precision. Similarly, the distance between each second radial reference surface 21R and the central axis of the turbine can also be made to match with high precision.

[0055] The slits 31x and 21x require accuracy in the distances from the turbine center axis of the first radial reference plane 31R and the second radial reference plane 21R, but even if the positions are slightly offset along the first radial reference plane 31R and the second radial reference plane 21R, the functions are not affected.

[0056] However, as long as the above-mentioned essential effect (1) can be obtained, it is not necessary to provide the slits 31x and 21x in order to form the first radial reference surface 31R and the second radial reference surface 21R. For example, a protrusion is preliminarily formed at a predetermined position on the outer peripheral surface of the flanges 31v and 21v of the first shell and the second shell to form the first radial reference surface 31R and the second radial reference surface 21R. In addition, it is also possible to consider a method of forming the first radial reference surface 31R and the second radial reference surface 21R by cutting off the end surface of the protrusion by machining. In this case, the first radial reference surface 31R and the second radial reference surface 21R are located at a position farther from the center axis of the turbine than the outer peripheral surface of the flanges 31v and 21v.

[0057] (3) As described above, when the circumferential positions of the first housing and the second housing adjacent in the axial direction are aligned, the first tilt reference surface 31C and the second tilt reference surface 21C are set so that the circumferential positions of each other coincide. Therefore, when the single-piece assembly of the turbine housing is performed, the relative circumferential positions of the first housing and the second housing are aligned by aligning the positions of the first tilt reference surface 31C and the second tilt reference surface 21C. Therefore, according to this embodiment, a dedicated alignment jig is not required when aligning the circumferential directions of the first housing and the second housing. In addition, since the operation is easy, the operation time for aligning the circumferential directions of the first housing and the second housing can be shortened, and the single-piece assembly time of the turbine housing can be shortened.

[0058] (4) In the present embodiment, the lower half shells 31L and 21L of the first shell and the second shell are provided with cutouts 31y and 21y that are opposed to the upper half shells 31U and 21U. The end surfaces of the flanges 31h1 and 21h1 of the upper half shell 31U facing the cutouts 31y and 21y are set as the first tilt reference surface 31C and the second tilt reference surface 21C. By setting the end surfaces as the tilt reference surfaces, the accuracy of the reference position can be easily ensured.

[0059] In addition, by providing the cutouts 31y and 21y, as described above, it is possible to Figure 4 A metal member having a flat surface, such as a metal member M of the abutment, a scale, etc., is abutted against the tilt reference surface. Thus, it is easy to measure the height difference between the first tilt reference surface 31C and the second tilt reference surface 21C, that is, the offset amount of the circumferential position of the first shell and the second shell. This also helps to facilitate the operation of angular alignment of the first shell and the second shell.

[0060] However, the boundary between the upper half shell 31U, 21U and the lower half shell 31L, 21L can be visually confirmed even without the cutouts 31y, 21y. Therefore, based on the facing surfaces of the upper half shell 31U, 21U and the lower half shell 31L, 21L as a reference, the cutouts 31y, 21y are not necessarily required.

[0061] In addition, as long as the positional accuracy of the first tilt reference surface 31C and the second tilt reference surface 21C can be ensured, it is not necessary to set the opposing end surfaces of the upper half shell and the lower half shell as the tilt reference surfaces. Figure 3 , Figure 5 If the circumferential processing positions of the surfaces N1, N2) are aligned with high precision, these surfaces can also be used as tilt reference surfaces.

[0062] (5) In addition, in order to fix the relative position of the first shell and the second shell, a positioning hole 42 is provided in the first shell and a positioning pin 43 is erected, and on the other hand, a through hole 41 with a surplus size relative to the positioning pin 43 is provided in the second shell. Therefore, after the axial alignment and angular alignment of the first shell and the second shell are completed, even if the centers of the through hole 41 and the positioning hole 42 are slightly offset, the positioning pin 43 can be easily driven into the positioning hole 42 through the through hole 41. In addition, there is a gap between the positioning pin 43 and the through hole 41, and at the time of driving the positioning pin 43, the positioning pin 43 and the second shell are not in a fixed relationship, but the positioning pin 43 is embedded in the bushing 44 and the through hole 41 and the bushing 44 are welded. As a result, the positioning pin 43 is fixed by the bushing 44 and the welding portion 45, and the first shell and the second shell can be fixed to each other in the state where the alignment is completed.

[0063] Usually, after the alignment work is performed, the flanges of the first shell and the second shell are subjected to common hole processing, and the positioning pins are driven into the flanges to fix the aligned first shell and the second shell. In this case, the first shell and the second shell need to be transferred to the machine tool in a stacked state after the alignment, and the common hole processing also requires time.

[0064] In contrast, in the present embodiment, as described above, the inner diameter of the through hole 41 is set to have a surplus size relative to the outer diameter of the positioning pin 43. Therefore, even if the centers of the through hole 41 and the positioning hole 42 are slightly offset, the first shell and the second shell can be fixed by driving the positioning pin 43 into the positioning hole 42, covering the bushing 44 on the positioning pin 43 and welding. In this way, the through hole 41 and the positioning hole 42 do not require strict positional accuracy, so they can be opened in advance before the alignment of the first shell and the second shell. Therefore, after the alignment work is completed, the first shell and the second shell can be fixed on the spot, and there is no need to transfer the first shell and the second shell to the machine tool for common hole processing. This also helps to shorten the process of single-piece assembly of the turbine chamber.

Claims

1. A turbine casing, which is axially divided into a first casing and a second casing connected by flanges to each other, and the first casing and the second casing are respectively divided into two parts, an upper half casing and a lower half casing, when viewed from the axial direction, wherein: The turbine casing has a set of three or more first radial reference surfaces provided on the outer peripheral portion of the flange of the first housing and a second radial reference surface provided on the outer peripheral portion of the flange of the second housing in the circumferential direction. Each first radial reference plane is located at an equal distance from the central axis of the turbine. Each second radial reference plane is located at an equal distance from the central axis of the turbine, The turbine casing is configured such that a positional relationship between the first radial reference plane and the second radial reference plane is equal in each set.

2. The turbine chamber according to claim 1, wherein: The first radial reference surface and the second radial reference surface are inner wall surfaces of slits provided in the outer peripheral portions of flanges of the first housing and the second housing, and are surfaces parallel to the turbine center axis and facing radially outward.

3. The turbine chamber according to claim 1, wherein: The turbine housing has: A first tilt reference surface, which is provided on the outer peripheral portion of the flange of the first housing; and A second tilt reference surface is provided on the outer peripheral portion of the flange of the second housing, The first roll reference plane and the second roll reference plane have the same circumferential position.

4. The turbine chamber according to claim 3, wherein: The first shell and the second shell are respectively provided with a cutout, wherein the cutout is provided on one side of the upper half shell and the lower half shell in a manner opposite to the other side, and an opposing surface of the other side opposite to the one side faces the cutout, The opposing surface facing the notch constitutes the first tilt reference surface and the second tilt reference surface.

5. The turbine chamber according to claim 1, wherein: The turbine chamber comprises: a through hole provided on the flange of the second housing in parallel with the central axis of the turbine; a positioning pin inserted into the flange of the first housing through the through hole; and A bushing is embedded in the through hole with the positioning pin, and is fixed to the flange of the second housing by welding, thereby filling a gap between the positioning pin and the through hole.

6. A gas turbine, wherein: The gas turbine includes the turbine casing according to claim 1 .

7. A method for aligning the first shell and the second shell of a turbine casing which are axially divided into a first shell and a second shell connected by flanges to each other, and the first shell and the second shell are respectively divided into two parts, an upper half shell and a lower half shell, when viewed from the axial direction, wherein: The alignment method comprises the following steps: The first housing and the second housing are formed in such a manner that three or more sets of first radial reference surfaces provided on the outer peripheral portion of the flange of the first housing and second radial reference surfaces provided on the outer peripheral portion of the flange of the second housing are provided in the circumferential direction, and each of the first radial reference surfaces is located at an equal distance from the central axis of the turbine, and each of the second radial reference surfaces is located at an equal distance from the central axis of the turbine; placing the second housing on the first housing so that the flanges thereof face each other in a posture where the central axis of the turbine faces up and down; as well as The position of the second housing relative to the first housing is adjusted in such a manner that the positional relationship between the first radial reference plane and the second radial reference plane is equal in each group.

8. The alignment method according to claim 7, wherein: The alignment method comprises the following steps: A first roll reference surface is pre-set on the outer periphery of the flange of the first housing, and a second roll reference surface is pre-set on the outer periphery of the flange of the second housing; and When adjusting the position of the second housing relative to the first housing, the circumferential positions of the first roll reference surface and the second roll reference surface are made consistent.

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