Tool and method for adjusting concentricity of low-pressure turbine guider

Abstract

The invention discloses a tool and method for adjusting the concentricity of a low-pressure turbine guider, and belongs to the technical field of aero-engine assembly. The tool comprises a bottom plate, a threaded push rod, a push block and a screw rod mounting block. The screw rod mounting block is arranged on the top surface of the bottom plate, and the threaded push rod is screwed in a thread of the screw rod mounting block; a guide assembly is arranged on the top face of the bottom plate, and the push block is in sliding fit with the guide assembly. The front end of the threaded push rod is connected with the push block and used for pushing the push block to move in the front-back direction of the clamp. According to the method, at least three tools are evenly distributed on a combustion chamber casing in the circumferential direction, all the threaded push rods are rotated to drive the push blocks to move linearly, the pre-installed low-pressure turbine guider is pushed to translate in the radial direction, jumping is monitored in combination with the dial indicator, the position of the low-pressure turbine guider is cooperatively adjusted through the cross approximation strategy, and final fastening is conducted till the concentricity is qualified.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aero-engine assembly, and particularly relates to a tool and method for adjusting the concentricity of a low-pressure turbine guide vane. BACKGROUND

[0002] The low-pressure turbine guide vane is installed in a combustion chamber case and located at the inlet of a turbine rotor, and its function is to adjust the airflow direction through guide vanes to provide a pre-swirl field for the subsequent rotor blades. The axis of the installed low-pressure turbine guide vane is required to be coaxial with the rotor center. If the concentricity of the low-pressure turbine guide vane and the rotor is not adjusted in place, the high-pressure turbine blades on the rotor will expand under high temperature and high pressure, which may cause the high-pressure turbine blades to rub against the low-pressure turbine guide vane at high speed, affecting the safety and reliability of the engine.

[0003] During the assembly of the low-pressure turbine guide vane, the radial position of the low-pressure turbine guide vane in the combustion chamber case needs to be continuously adjusted, and the runout of the low-pressure turbine guide vane is observed through a dial indicator to ensure that the axis of the low-pressure turbine guide vane is coaxial with the rotor axis. At present, the method for adjusting the concentricity of the low-pressure turbine guide vane is to use a rubber hammer to knock and adjust, and the specific operation is as follows: the rubber hammer is used to knock the outer periphery of the low-pressure turbine guide vane to give an instantaneous impact force, so that the low-pressure turbine guide vane moves slightly in a certain direction, and the runout of the low-pressure turbine guide vane is observed through the dial indicator to adjust the concentricity of the low-pressure turbine guide vane.

[0004] The method of using a rubber hammer to knock and adjust has the following disadvantages: (1) When knocking, the size and direction of the impact force are uncertain, and the position and direction of the movement of the low-pressure turbine guide vane cannot be determined, so the adjustment cannot be quickly performed, and the adjustment process is time-consuming and laborious.

[0005] (2) The method of knocking and adjusting is easy to damage the low-pressure turbine guide vane.

[0006] Therefore, a tool and method for adjusting the concentricity of a low-pressure turbine guide vane are provided to solve the above technical problems. SUMMARY

[0007] The main purpose of the present application is to provide a tool and method for adjusting the concentricity of a low-pressure turbine guide vane to solve the above technical problems.

[0008] To achieve the above object, in one aspect, the application provides a tool for adjusting concentricity of a low-pressure turbine guide vane, comprising a base plate, a threaded push rod, a push block and a screw rod mounting block; the screw rod mounting block is arranged on the top surface of the base plate, and the threaded push rod is screwed into the screw rod mounting block; a guide assembly is arranged on the top surface of the base plate, and the push block is in sliding fit with the guide assembly; the front end of the threaded push rod is connected with the push block, and is used to push the push block to move along the front-rear direction of the jig.

[0009] Preferably, a handle is arranged on the rear end of the threaded push rod, and the axial direction of the handle is perpendicular to the axial direction of the threaded push rod.

[0010] Preferably, the guide assembly comprises a pressing plate and two supporting blocks arranged on the top surface of the base plate; the left and right ends of the pressing plate are respectively overlapped on the top surfaces of the supporting blocks and are fixed by screws; the top surface of the base plate, the bottom surface of the pressing plate and the opposite side surfaces of the two supporting blocks jointly form a guide hole, and the push block is in sliding fit with the guide hole.

[0011] Preferably, the side surface of the push block used to contact the low-pressure turbine guide vane is arranged as a concave arc surface, and a rubber pad is bonded on the concave arc surface.

[0012] Preferably, a bolt through hole is arranged on the base plate, and is used to fix the base plate to the mounting edge of the combustion chamber case.

[0013] Preferably, the front end of the threaded push rod is arranged as a light rod; the light rod is inserted into the push block, and the two are in rotary fit; an annular limiting groove is arranged on the light rod; a jack screw is arranged on the push block, and the jack screw is inserted into the annular limiting groove, and the jack screw does not tightly press the light rod.

[0014] In a second aspect, the application further provides a method for adjusting concentricity of a low-pressure turbine guide vane, and at least three tools described above are used, and the method comprises the following steps: S1: a plurality of the tools are fixedly arranged on the mounting edge of the combustion chamber case in circumferential uniform distribution; S2: the low-pressure turbine guide vane is pre-installed in the combustion chamber case without locking, and the end surface of the low-pressure turbine guide vane abuts against the top surface of the base plate of the tool; the threaded push rod of each tool is operated, so that the push block of each tool abuts against the outer circumferential surface of the low-pressure turbine guide vane; S3: a dial gauge is arranged on the rotor; the rotor is driven to rotate; the run-out of the low-pressure turbine guide vane is detected by the dial gauge, and the positions of the maximum and minimum run-out are marked; S4: the positions of the push blocks are finely adjusted by rotating the threaded push rods of the tools respectively, so that the low-pressure turbine guide vane is pushed to move radially in the combustion chamber case; and the concentricity of the low-pressure turbine guide vane is adjusted to the qualified range according to the change of the dial gauge.

[0015] Preferably, the number of jigs is four, and they are distributed in a cross shape; in step S4, a "cross approximation" strategy is used for collaborative adjustment: according to the positions of the maximum and minimum run-out, the low-pressure turbine guide vane is pushed in the direction of reduced run-out by operating the jigs in the corresponding positions, and the adjustment is iteratively adjusted alternately until the run-out is qualified.

[0016] Preferably, in step S4, after the concentricity is preliminarily adjusted and qualified, the fixing bolts of the low-pressure turbine guide vane are tightened step by step in a cross-over sequence, and the percentage indicator is continuously monitored during the tightening process to ensure that the concentricity is still qualified after final locking.

[0017] Preferably, after the low-pressure turbine guide vane is fixed, the jigs are removed from the mounting edge of the combustion chamber case, and the mounting dial gauge installed on the rotor is also removed.

[0018] Thanks to the above technical solutions, the application has the following advantages: (1) The adjustment process is accurately quantified and completely controllable: the application completely abandons uncertain impact force and replaces it with linear displacement generated by a precision screw pair. The number of turns or the angle of the handle rotated by the operator has a strict linear relationship with the displacement of the push block, so that the adjustment process changes from "experience-dependent" to "push block precise driving". The size, direction and final displacement of the push force are predictable and controllable, greatly improving the accuracy and one-time success rate of the adjustment.

[0019] (2) The traditional knocking method takes an average of 10 to 12 hours due to its trial adjustment mode. Using the work and "cross approximation" method provided by the application, qualified adjustment can be completed in about 2 to 3 hours, with an efficiency improvement of about 70%-80%, effectively solving the bottleneck process problem on the engine assembly line and greatly reducing labor costs and production cycle.

[0020] (3) The traditional impact knocking has the risk of causing surface damage, micro-deformation or internal micro-cracks to the parts. The application uses smooth and continuous mechanical propulsion throughout, completely eliminating the impact load. The concave arc surface at the front end of the push block and the rubber pad further disperse the contact stress and protect the product surface. This "flexible contact, rigid propulsion" method fundamentally eliminates the potential damage to the low-pressure turbine guide vane during the adjustment process.

[0021] (4) The application replaces the traditional manual knocking with mechanical fine adjustment, solving the problems of uncertain adjustment process, low efficiency and easy damage to parts, and achieving high-quality and high-efficiency assembly. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description only show some of the embodiments of the present application, and other drawings can be obtained by those of ordinary skill in the art without any creative effort based on these drawings.

[0023] Figure 1 A schematic view of the tooling provided by the present application; Figure 2 A schematic view after the push block is pushed forward; Figure 3 A schematic view of the connecting structure of the threaded push rod and the push block.

[0024] Explanation of reference numerals: 1, bottom plate; 2, threaded push rod; 2a, annular limiting groove; 2b, polished rod; 3, push block; 3a, concave arc surface; 4, screw mounting block; 5, guide assembly; 5a, pressing plate; 5b, support block; 6, handle; 7, jackscrew; 100, mounting edge. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without any creative effort belong to the scope of protection of the present application.

[0026] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present application are only used to explain the relative positional relationship, movement condition, etc. between components in a certain posture (as shown in the drawings), and if the certain posture changes, the directional indications also change accordingly.

[0027] In combination with Figure 1 and Figure 2 shown, in one aspect, the present embodiment provides a tooling for adjusting the concentricity of a low-pressure turbine guide vane, comprising a bottom plate 1, a threaded push rod 2, a push block 3 and a screw mounting block 4; the screw mounting block 4 is arranged on the top surface of the bottom plate 1, and the threaded push rod 2 is screwed into the thread of the screw mounting block 4; a guide assembly 5 is arranged on the top surface of the bottom plate 1, and the push block 3 is in sliding cooperation with the guide assembly 5; the front end of the threaded push rod 2 is connected with the push block 3, and is used to push the push block 3 to move along the front-back direction of the clamp.

[0028] The main components of the tooling are as follows: The base plate 1 is the mounting base and reference for the whole tooling. It is usually a piece of metal plate, such as steel or aluminum alloy plate, with sufficient rigidity and flatness. There are bolt through holes on the base plate 1 for fastening it to the mounting flange 100 of the combustion chamber case. Through these bolt through holes and the matched high-strength bolts, the whole tooling can be firmly mounted on the mounting flange 100 of the combustion chamber case, ensuring that the tooling remains absolutely stable during adjustment.

[0029] The screw mounting block 4 is a key support and transmission conversion component, which is a square steel structure and is integrated with the base plate 1 by welding or screw fastening. The center of the screw mounting block is processed with a high-precision internal threaded hole for matching with the threaded push rod 2.

[0030] The threaded push rod 2 is a precision screw that matches the internal threaded hole of the screw mounting block 4. It is screwed into the threaded hole of the screw mounting block 4. When the threaded push rod 2 rotates, according to the transmission principle of the threaded pair, it will produce axial linear motion (forward or backward) relative to the screw mounting block. The threaded push rod 2 constitutes the power input and displacement generation unit of the tooling.

[0031] The push block 4 is the component that directly contacts and transmits the thrust force with the outer peripheral surface of the low-pressure turbine guide vane. It is made of high-strength material, and its design needs to consider the contact form and wear resistance with the guide vane.

[0032] The guide assembly 5 is fixed to the top surface of the base plate 1, and its core function is to provide a high-precision and constrained linear motion track for the push block 3. The push block 3 forms a sliding fit with the guide assembly, which means that the push block 3 can only move in the single direction defined by the guide assembly (i.e. the radial direction of the low-pressure turbine guide vane), and cannot produce displacement or deflection or lift in other directions. This ensures that the motion transmitted from the threaded push rod 2 is converted into pure radial thrust on the low-pressure turbine guide vane without deviation.

[0033] The front end of the threaded push rod 2 is connected with the push block 3. This connection needs to meet a key condition: it can convert the rotational motion of the threaded push rod 2 into linear motion of the push block, while avoiding the push block rotating with the threaded push rod. Through this connection and transmission relationship, rotating the threaded push rod 2 can accurately drive the push block 3 to move linearly along the path defined by the guide assembly 5.

[0034] In this embodiment, a handle 6 is installed at the rear end of the threaded push rod 2, and the axial direction of the handle 6 is perpendicular to the axial direction of the threaded push rod 2. In order to provide better operating torque and convenience, the axial direction of the handle is perpendicular to the axial direction of the threaded push rod, forming a T-shaped structure. This allows the operator to generate a larger rotational torque with smaller hand force.

[0035] The guiding assembly 5 comprises a pressing plate 5a and two supporting blocks 5b installed on the top surface of the bottom plate 1; the left and right ends of the pressing plate 5a are respectively overlapped on the top surface of the supporting blocks 5b and fixed by screws; the top surface of the bottom plate 1, the bottom surface of the pressing plate 5a and the opposite side surfaces of the two supporting blocks 5b jointly form a guiding hole, and the push block 3 is in sliding fit with the guiding hole. The two supporting blocks 5b are fixed and installed in parallel and at a certain distance on the top surface of the bottom plate 1. The pressing plate 5a is a long strip-shaped plate, and the left and right ends thereof are respectively overlapped on the top surface of the two supporting blocks 5b and fixed by screws. This design forms a closed guiding hole: the top surface of the bottom plate 1 serves as the bottom surface of the guiding hole, the opposite inner side surfaces of the two supporting blocks 5b serve as the two side surfaces of the guiding hole, and the bottom surface of the pressing plate 5a serves as the top surface of the guiding hole. The push block 3 is processed into a shape (usually rectangular or square) in precise sliding fit with the guiding hole and is embedded therein. This “all-surrounding” guiding structure provides the push block with high rigidity and straightness of movement, effectively prevents the push block from being stuck, creeping or deviated when being stressed, and ensures the absolute accuracy of the pushing direction.

[0036] In the embodiment, the side surface of the push block 3 for contacting the low-pressure turbine guide vane is provided as a concave arc surface 3a, and a rubber pad is bonded on the concave arc surface 3a. The curvature radius of the concave arc surface 3a is preferably matched with the outer circle radius of the pushed part of the low-pressure turbine guide vane. Compared with point contact, the surface contact or line contact design can better disperse the acting force and avoid local indentation or damage to the outer surface of the guide vane. In order to further enhance the protection effect and increase the friction force and prevent slipping, a layer of rubber pad or other suitable non-metallic elastic protection pad (such as polyurethane, nylon, etc.) can be bonded on the concave arc surface 3a.

[0037] The connection structure of the threaded push rod 2 and the push block 3 adopts a delicate "rotary connection and axial limiting" scheme. Specifically, the front end of the threaded push rod 2 is processed into a smooth cylinder, i.e. a smooth rod 2b. The smooth rod 2b is inserted into the blind hole of the corresponding size at the rear end of the push block 3, and the two are in sliding fit, thereby realizing rotary fit, i.e. the smooth rod 2b can freely rotate in the hole of the push block 3, and the push block 3 itself does not rotate. In order to axially limit the push block 3, prevent it from being pulled off the smooth rod 2b, and enable the push block 3 to be pulled back together with the threaded push rod 2 when the threaded push rod 2 retreats, an annular limiting groove 2a is processed on the smooth rod 2b. Correspondingly, a jack screw 7 is installed radially on the push block 3. Adjust the jack screw 7 so that the end thereof extends into the annular limiting groove 2a, but the key point is that the jack screw 7 does not tightly press the smooth rod 2b, i.e. does not produce hard contact or compression with the bottom or sidewall of the annular limiting groove 2a. This structure realizes two functions: one is to allow the threaded push rod 2 to freely rotate relative to the push block 3; the other is to realize bidirectional transmission of the push block 3 by the contact of the jack screw 7 with the two sides of the annular limiting groove 2a, i.e. to push the push block 3 when the threaded push rod 2 advances, and to pull the push block 3 when the threaded push rod 2 retreats.

[0038] In a second aspect, the embodiment provides a method for adjusting the concentricity of a low-pressure turbine guide vane. The method is based on the above-mentioned tooling and systematically solves the pain points of traditional processes. The core steps include: S1: tooling installation step. Select at least three (preferably four) toolings described in the present application. These toolings are evenly distributed and fixedly installed on the installation edge 100 of the combustion chamber case. When four toolings are used, the best layout is a cross-shaped distribution, i.e. 90 degrees apart from each other. The bottom plate 1 of each tooling is fastened to the installation edge 100 of the case by bolts, ensuring that all toolings are stable and reliable.

[0039] S2: pre-installation and abutting step. Place the low-pressure turbine guide vane in the predetermined installation position in the combustion chamber case for pre-installation. At this time, the final fixing bolts are not tightened, allowing a certain amount of radial float. Adjust the axial position of the low-pressure turbine guide vane so that its end face (usually the front installation edge) can stably abut against the top surface of all tooling bottom plates 1. This step provides an accurate axial positioning reference for the low-pressure turbine guide vane using the top surface of the bottom plate 1. Then, rotate the threaded push rod 2 (by handle 6) of each tooling in turn, so that the push block 3 of each tooling advances smoothly until its contact surface (such as the concave arc surface 3a with rubber pad) reliably abuts against the outer circumferential predetermined position of the low-pressure turbine guide vane. At this time, the low-pressure turbine guide vane is constrained in the circumferential direction by the push blocks 3 of multiple toolings.

[0040] S3: Measurement and marking step. Install a magnetic stand or a special fixture on the rotor of the engine, and fix a dial gauge (or a more accurate micrometer) on it. Adjust the measuring head of the dial gauge to be perpendicular and contact the inner ring of the low-pressure turbine guide vane or a precisely machined reference surface. Slowly and uniformly rotate the engine rotor manually, and observe the swing of the dial gauge pointer. Record the runout at the entire circumference, and accurately find the positions of the maximum runout point (high point) and the minimum runout point (low point) by analyzing the readings, and make clear marks. This provides a clear basis for subsequent targeted adjustment.

[0041] S4: Fine adjustment and final tightening step. According to the positions of the runout extreme points marked in step S3, the operator begins fine adjustment. By rotating the threaded push rods 2 of the corresponding orientation fixtures respectively, the position of the push block 3 is finely controlled, thereby exerting accurate radial thrust on the low-pressure turbine guide vane to produce the desired radial translation within the combustion chamber housing. During the adjustment process, the change in the dial gauge reading needs to be closely observed.

[0042] When using four fixtures distributed in a cross shape, the "cross approximation" strategy is recommended. The basic principle is: coordinate the operation of two pairs of fixtures located in the diametrical directions of the maximum and minimum runout. For example, if the runout is maximum in the north direction (i.e., the center of the part is biased towards the south), the threaded push rod of the fixture in the north direction is appropriately screwed in to push the part towards the south; at the same time, if the runout is minimum in the west direction (i.e., the center of the part is biased towards the east), the threaded push rod of the fixture in the west direction is appropriately unscrewed (or supplemented by screwing in the fixture in the east direction) to make the part have a tendency to move westward. Through this alternating and iterative adjustment in the cross direction, the high point of the runout is gradually "pressed down", and the low point is "lifted up", so that the actual center of the part continuously approaches the theoretical center of the rotor, until the runout on the entire circumference is uniformized and reduced to within the qualified tolerance range.

[0043] After the preliminary adjustment is qualified, the final tightening stage is entered. The fixing bolts of the low-pressure turbine guide vane are gradually and in stages tightened in a cross sequence (for example, first tighten the 12 o'clock direction, then the 6 o'clock, then the 3 o'clock, and finally the 9 o'clock, or a similar cross sequence). After each tightening, the rotor is rotated again, and the runout value is monitored by the dial gauge to ensure that the concentricity does not change out of tolerance under the action of the bolt pretightening force. If it is found that the runout changes due to tightening, the fixtures can be adjusted again to compensate before the bolts are completely locked. This is repeated until all the bolts are completely tightened according to the specified torque, and the dial gauge confirms that the concentricity remains stable and qualified.

[0044] Finally, when the low-pressure turbine guide vane is reliably fixed, reverse rotation of the threaded push rod 2 of all tooling makes the push block 3 retreat and disengage from the low-pressure turbine guide vane. Then, the bolts that fix the tooling on the casing are removed, and the entire tooling is removed from the engine. At the same time, the dial gauge and its gauge bracket installed on the rotor are also removed. The entire adjustment process is thus successfully completed.

[0045] The present application successfully transforms a highly dependent proprietary technology on individual technician skills into a set of standardized processes based on special tooling and clear procedures. The operator only needs to follow the steps to stably reproduce high-quality adjustment results. This greatly reduces the dependence on specific high-skilled personnel, and is conducive to the quality consistency control in mass production and the standardized management of assembly technology.

[0046] The above only describes the preferred embodiments of the present application, and does not limit the patent scope of the present application. Any equivalent structural transformation, direct / indirect application in other related technical fields, or the like within the inventive concept of the present application and using the content of the present application specification and drawings are included in the patent protection scope of the present application.

Claims

1. A tooling for adjusting the concentricity of a low-pressure turbine guide vane, characterized in that, Includes a base plate (1), a threaded push rod (2), a push block (3), and a screw mounting block (4); The screw mounting block (4) is disposed on the top surface of the base plate (1). The threaded push rod (2) is screwed into the thread of the screw mounting block (4); A guide assembly (5) is provided on the top surface of the base plate (1), and the push block (3) slides in cooperation with the guide assembly (5); The front end of the threaded push rod (2) is connected to the push block (3) and is used to push the push block (3) to move along the front and rear direction of the clamp.

2. The tooling according to claim 1, characterized in that, A handle (6) is installed at the rear end of the threaded push rod (2), and the axial direction of the handle (6) is perpendicular to the axial direction of the threaded push rod (2).

3. The tooling according to claim 1, characterized in that, The guide assembly (5) includes a pressure plate (5a) and two support blocks (5b) installed on the top surface of the base plate (1); the left and right ends of the pressure plate (5a) are respectively attached to the top surface of the support blocks (5b) and fixed by screws; The top surface of the base plate (1), the bottom surface of the pressure plate (5a), and the opposite sides of the two support blocks (5b) together form a guide hole, and the push block (3) slides in cooperation with the guide hole.

4. The tooling according to claim 1, characterized in that, The side of the pusher (3) that is in contact with the low-pressure turbine guide is set as a concave arc surface (3a), and a rubber pad is attached to the concave arc surface (3a).

5. The tooling according to claim 1, characterized in that, The base plate (1) has bolt holes for fixing it to the mounting edge of the combustion chamber casing.

6. The tooling according to claim 1, characterized in that, The front end of the threaded push rod (2) is set as a smooth rod (2b); the smooth rod (2b) is inserted into the push block (3), and the two are rotated together; An annular limiting groove (2a) is provided on the light rod (2b); a set screw (7) is installed on the push block (3), and the set screw (7) extends into the annular limiting groove (2a), and the set screw (7) does not press against the light rod (2b).

7. A method for adjusting the concentricity of a low-pressure turbine guide vane, characterized in that, Using at least three tooling fixtures as described in any one of claims 1 to 6, the process includes the following steps: S1: The plurality of tooling fixtures are circumferentially and evenly fixedly installed on the mounting side (100) of the combustion chamber casing; S2: Pre-install the low-pressure turbine guide in the combustion chamber casing but do not lock it, and make the end face of the low-pressure turbine guide abut against the top surface of the base plate (1) of the tooling. Operate the threaded push rod (2) of each tooling so that the push block (3) of each tooling abuts against the outer peripheral surface of the low-pressure turbine guide. S3: Install a dial indicator on the rotor. By driving the rotor to rotate, use the dial indicator to detect the runout of the low-pressure turbine guide and mark the positions of maximum and minimum runout. S4: By rotating the threaded push rod (2) of each tooling respectively, the position of the push block (3) is finely adjusted, thereby pushing the low-pressure turbine guide to move radially within the combustion chamber casing, and adjusting the concentricity of the low-pressure turbine guide to the qualified range according to the change of the percentage reading.

8. The method according to claim 7, characterized in that, The tooling consists of four pieces, arranged in a cross shape. In step S4, a "cross approach" strategy is used for coordinated adjustment: based on the positions of the maximum and minimum fluctuations, the low-pressure turbine guide is pushed in the direction of decreasing fluctuation by operating the tooling in the corresponding position, and the adjustment is iteratively adjusted alternately until the fluctuation is acceptable.

9. The method according to claim 7 or 8, characterized in that, In step S4, after the concentricity is initially adjusted to be qualified, the fixing bolts of the low-pressure turbine guide are tightened step by step in a cross-shaped sequence, and the percentage gauge reading is continuously monitored during the tightening process to ensure that the concentricity is still qualified after final locking.

10. The method according to claim 9, characterized in that, After the low-pressure turbine guide is fixed, remove the tooling from the mounting edge (100) of the combustion chamber casing, and at the same time remove the mounting dial indicator mounted on the rotor.

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