Axial locking device for closing the last-stage blade and its disassembly and assembly method

Abstract

The present invention discloses a last-stage blade closed axial locking device and a disassembly and assembly method thereof. The last-stage blade closed axial locking device is used to lock the blade on the hub, and includes: an axial positioning key; two packing keys; a split filling assembly, including a split filling block and a wedge block. The split filling block is provided with a deformation part for sleeving on the wedge block. The split filling block deforms along the wedge block under the action of an external force to abut against the two packing keys, so as to limit the axial positioning key and thus lock the blade on the hub. It uses the split filling block of the split filling assembly to be deformed by force to fix the packing key, and then fixes the axial positioning key to lock the blade on the hub. When the blade needs to be disassembled, only the split filling block needs to be taken out, and then the packing key and the axial positioning key are taken out in sequence. This disassembly process does not require using tools to drill relevant components, ensuring that the hub will not be damaged, and can effectively save the maintenance work period of the last-stage blade.

Description

Technical Field

[0001] The present invention relates to the technical field of steam turbine maintenance, and particularly relates to a closing axial locking device for a last-stage blade and a disassembly and assembly method thereof. Background Art

[0002] Steam turbine maintenance is an important task in power plant maintenance projects. When the low-pressure cylinder is fully maintained, all the last-stage blades need to be disassembled and inspected. When the last-stage blades of the steam turbine are operating, they will be subjected to axial thrust due to steam flow impact, and an axial positioning key is required to position and fix the last-stage blades.

[0003] The installation of the axial positioning key for the blade is to install one blade first, and then install the axial positioning key to position and fix this blade. The main body of the axial positioning key is stuck on the wheel groove and a small boss of the axial positioning key protrudes and is stuck on the back arc of the blade for positioning and fixing. Because when installing the last blade after installing the whole circle of last-stage blades, due to the obstruction of the first blade, it is no longer possible to install a normal axial positioning key. At this time, a special axial positioning key needs to be installed, and two filling pieces are used to fix the last blade. The two filling pieces are usually of a block structure and are fixed by an interference-fit fixing block between the two filling pieces. When disassembling the axial positioning key, it is necessary to first damage the fixing block, then clean out the fixing block and then take out the two filling pieces separately, and finally take out the axial positioning key. This operation takes a long time, and when damaging the fixing block, tools such as drills are likely to drill too far and damage the boss of the hub. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a closing axial locking device for a last-stage blade and a disassembly and assembly method thereof.

[0005] The technical solution adopted by the present invention to solve its technical problem is to construct a closing axial locking device for a last-stage blade, which is used to lock the blade on the hub. The hub is provided with a plurality of bosses arranged at intervals in the circumferential direction, and a wheel groove is formed between two adjacent bosses for installing the root of the blade. A limiting portion is provided at the top of each boss, and a limiting groove that is radially and circumferentially through is provided between the upper surface of the limiting portion and the upper surface of the boss. The axial dimension of the top of the limiting groove is relatively reduced to form a notch, and the limiting groove and the notch penetrate through the opposite side surfaces of the limiting portion in the circumferential direction. The limiting groove is divided into a first space and a second space arranged in the circumferential direction; a groove is provided on one side of the root facing the limiting groove. The closing axial locking device for the last-stage blade includes:

[0006] An axial positioning key, which is used to be installed in the first space. The axial positioning key includes a plate-shaped main body, and a protrusion is provided on one side of the plate-shaped main body facing the groove for extending into the groove;

[0007] Two packing keys for installation in the second space, with a predetermined gap between opposite sides of the two packing keys;

[0008] A split filling assembly for installation in the predetermined gap, the split filling assembly including a split filling block and a wedge block. The split filling block includes a positioning portion and a deformation portion for sleeving on the wedge block. The deformation portion can axially deform along the wedge block under the action of a radial external force to press against the two packing keys, and the two packing keys further press against the inner walls on both sides of the second space to be fixed in the second space, so as to limit the axial positioning key and thus lock the blade on the hub.

[0009] In some embodiments, a connecting portion is provided at the top of the positioning portion; the connecting portion is a threaded hole that does not penetrate the positioning portion, or the connecting portion is a snap ring.

[0010] In some embodiments, limiting surfaces are respectively provided on opposite sides of the two packing keys; the limiting surfaces are rectangular inclined surfaces that extend obliquely away from the split filling assembly from top to bottom;

[0011] Wherein, the deformation portion presses against the limiting surface after deformation.

[0012] In some embodiments, the cross-sectional shape of the plate-shaped main body is a T-shaped structure; the cross-sectional shape of the limiting groove is a T-shaped structure.

[0013] In some embodiments, the thickness of the plate-shaped main body is half of the depth direction of the limiting groove, and the depth direction is the circumferential direction.

[0014] The present invention also discloses a method for disassembling and assembling a closing axial locking device for a last-stage blade, which is applied to the closing axial locking device for a last-stage blade in any of the above embodiments, and includes an installation step and a removal step. The installation step includes:

[0015] A1: Install the axial positioning key into the first space of the limiting groove, and axially push the axial positioning key to install the protrusion into the groove at the root of the blade;

[0016] A2: Respectively install the two packing keys into the second space of the limiting groove from the notch, and the two packing keys are separated by a predetermined gap. Then install the split filling assembly into the predetermined gap, and apply a radial inward force to the positioning portion of the split filling block to deform the split filling block along the wedge block to press against the two packing keys;

[0017] The removal step includes:

[0018] S1: Connect the top of the split filling block with a pulling tool, apply a radially outward force to the positioning part at the top of the split filling block through the pulling tool, and pull the split filling block out of the limiting groove from the notch.

[0019] S2: Take out the wedge block and the two packing keys in sequence.

[0020] S3: Push the axial positioning key circumferentially to disengage the protrusion from the root of the blade, push the blade axially along the wheel groove, remove the blade, and then remove the axial positioning key to complete the disassembly.

[0021] In some embodiments, in S1: Connect the threaded hole at the top of the positioning part with a pin extractor, and pull the split filling block out of the limiting groove from the notch.

[0022] In some embodiments, in S1, use an extended center punch to make a center punch mark at the middle position of the split filling block, use an extended drill bit to drill a hole to the top position of the wedge block, and use a tap to tap a threaded hole in the hole to form the threaded hole.

[0023] Alternatively, the threaded hole is a prefabricated hole.

[0024] In some embodiments, in S2, use a magnetic bar to suck out the wedge block from the notch.

[0025] In some embodiments, in S2, use an extended chisel to move one of the packing keys to the relative position of the notch of the limiting groove, use a pair of needle-nose pliers to take out the packing key, and then take out the other packing key.

[0026] Implementing the present invention has the following beneficial effects: Applying the axial locking device for the last-stage blade and its disassembly and assembly method, the split filling block of the split filling component deforms under force to fix the packing key, and further fixes the axial positioning key to lock the blade on the hub. When the blade needs to be disassembled, only the split filling block needs to be taken out, and then the packing key and the axial positioning key are taken out in sequence. This disassembly process does not require drilling relevant components with tools, ensuring that the hub will not be damaged, and can effectively save the maintenance work period of the last-stage blade. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the present invention, the present invention will be further described below in conjunction with the drawings and embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts. In the drawings:

[0028] Figure 1Schematic diagram of the application of the axial locking device for closing the last-stage blade in some embodiments of the present invention;

[0029] Figure 2 Schematic diagram of the structure of the last-stage blade in some embodiments of the present invention;

[0030] Figure 3 is Figure 2 detailed view of;

[0031] Figure 4 Schematic diagram of the application details of the axial locking device for closing the last-stage blade in some embodiments of the present invention;

[0032] Figures 5 to 7 Schematic diagram of the structure of the axial locking device for closing the last-stage blade in some embodiments of the present invention;

[0033] Figure 8 and Figure 9 Schematic diagram of the structure of the axial positioning key in some embodiments of the present invention;

[0034] Figure 10 Schematic diagram of the structure of the packing key in some embodiments of the present invention;

[0035] Figure 11 Schematic diagram of the structure of the split filling block when no deformation occurs in some embodiments of the present invention;

[0036] Figure 12 Schematic diagram of the structure of the split filling block when deformation occurs in some embodiments of the present invention;

[0037] Figure 13 Schematic diagram of the structure of the wedge block in some embodiments of the present invention;

[0038] Figure 14 Schematic diagram of the structure of the lengthened chisel head in some embodiments of the present invention;

[0039] Figure 15 Schematic diagram of the structure of the lengthened center punch in some embodiments of the present invention;

[0040] Figure 16 Schematic diagram of the structure of the lengthened drill bit in some embodiments of the present invention;

[0041] Figure 17 Schematic diagram of the structure of the pin extractor in some embodiments of the present invention;

[0042] Figure 18 Schematic diagram of the application of the pin extractor in some embodiments of the present invention;

[0043] Figure 19 Schematic diagram of the structure of the lengthened chisel in some embodiments of the present invention. Detailed Implementation Modes

[0044] In order to have a clearer understanding of the technical features, objectives, and effects of the present invention, the detailed implementation modes of the present invention will now be described in detail with reference to the accompanying drawings. In the following description, it should be understood that the orientation or positional relationships indicated by terms such as "front", "rear", "upper", "lower", "left", "right", "longitudinal", "transverse", "vertical", "horizontal", "top", "bottom", "inner", "outer", "head", "tail", etc. are based on the orientation or positional relationships shown in the accompanying drawings and are constructed and operated in a specific orientation, and are only for the convenience of describing the present technical solution, rather than indicating that the indicated devices or elements must have a specific orientation. Therefore, it should not be construed as a limitation to the present invention.

[0045] It should also be noted that, unless otherwise clearly specified and defined, terms such as "installation", "connection", "coupling", "fixation", "setting", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements. When an element is referred to as being "on" or "under" another element, the element can be "directly" or "indirectly" located above the other element, or there may also be one or more intermediate elements. Terms such as "first", "second", "third", etc. are only for the convenience of describing the present technical solution and should not be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first", "second", "third", etc. may explicitly or implicitly include one or more of such features. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0046] In the following description, specific details such as specific system structures and technologies are presented for the purpose of illustration rather than limitation, so as to thoroughly understand the embodiments of the present invention. However, those skilled in the art should clearly understand that the present invention can also be implemented in other embodiments without these specific details. In other cases, the detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid unnecessary details from interfering with the description of the present invention.

[0047] Please refer to Figures 1 to 7The hub 2 is provided with a plurality of bosses 21 arranged at intervals along the circumferential direction, and a wheel groove A is formed between two adjacent bosses 21 for installation of the root 11 of the blade 1. A limiting portion 22 is provided on the top of each boss 21, and a limiting groove 221 is provided on the limiting portion 22 between its upper surface and the upper surface of the boss 21, which is radially and circumferentially penetrating. The axial dimension of the top of the limiting groove 221 is relatively reduced to form a notch 222, and the limiting groove 221 and the notch 222 also penetrate the opposite sides of the limiting portion 22 in the circumferential direction. The limiting groove 221 is divided into a first space and a second space arranged in the circumferential direction, and the first space is arranged toward the blade 1; a groove 111 is provided on the side of the root 11 facing the limiting groove 221, and the last-stage blade closed axial locking device 3 includes:

[0048] The axial positioning key 31 is used to be installed in the first space. The axial positioning key 31 includes a plate-shaped body 311. The plate-shaped body 311 is provided with a protrusion 312 on a side facing the groove 111, so as to extend into the groove 111.

[0049] Two packing keys 32 are used to be installed in the second space, and a predetermined gap is provided between opposite sides of the two packing keys 32 to facilitate the subsequent installation of a split filling assembly 33;

[0050] The split filling assembly 33 is used to be installed in a predetermined gap. The split filling assembly 33 includes a split filling block 331 and a wedge block 332. The split filling block 331 includes a positioning portion 3311 and a deformation portion 3312 for being sleeved on the wedge block 332. The deformation portion 3312 can be axially deformed along the wedge block 332 under the action of radial external force to press against the two filling keys 32. The two filling keys 32 further press against the inner walls on both sides of the second space and are fixed in the second space to limit the axial positioning key 31 and thereby lock the blade 1 on the hub 2.

[0051] Recombination Figure 8 and Figure 9 Preferably, the shape of the plate-like body 311 is similar to the cross-sectional shape of the limiting groove 221. The limiting groove 221 forms two latches 2211 at both ends along the axial direction of the hub 2. In the radial direction, the axial positioning key 31 cannot be separated from the limiting groove 221 from the notch 222. In the circumferential direction, the axial positioning key 31 is surrounded by two filling keys 32. Therefore, the axial positioning key 31 cannot be separated from the limiting groove 221, and the blade can be fixed.

[0052] The cross-sectional shape of the limiting groove 221 is generally a T-shaped structure. The plate-shaped main body 311 is generally T-shaped, and it may include a main body portion 3111 and two protruding portions 3112 connected to the lower side surface of the main body portion 3111. The two protruding portions 3112 are used to extend into and be limited in the two clamping positions 2211. Thus, the plate-shaped main body 311 is fixed in the limiting groove 221. The sizes of the two protruding portions 3112 may be smaller than the sizes of the two clamping positions 2211, so that the axial positioning key 31 can appropriately move along the depth direction of the limiting groove 221 (the tangential direction of the circumference), and the subsequent two packing keys 32 and the split filling assembly 33 can limit the axial positioning key 31.

[0053] The protrusion 312 is provided on one side surface of the plate-shaped main body 311, and the bottom surface of the protrusion 312 is flush with the bottom surface of the plate-shaped main body 311. The cross-sectional shape of the protrusion 312 is similar to or the same as the cross-sectional shape of the groove 111, and the cross-sectional size of the protrusion 312 is similar to or the same as the cross-sectional size of the groove 111.

[0054] Preferably, the thickness of the plate-shaped main body 311 is half of the depth direction of the limiting groove 221. The depth direction is the circumferential direction of the hub 2, that is, the depth of the aforementioned first space is equal to the depth of the second space, which can be half of the depth of the limiting groove 221. Of course, in some other embodiments, the size of the plate-shaped main body 311 can also be appropriately adjusted according to requirements, and no specific limitation is made here.

[0055] Combined with Figure 10 As shown, limiting surfaces 323 are respectively provided on opposite sides of the two packing keys 32; the limiting surfaces 323 are rectangular inclined surfaces, and the limiting surfaces 323 extend obliquely downward from top to bottom away from the split filling assembly 33.

[0056] Among them, the deformed portion 3312 abuts against the limiting surface 323 after deformation. That is, at least a partial inclined surface fit can be formed between the deformed portion 3312 and the packing key 32.

[0057] In some embodiments, the packing key 32 may be generally L-shaped, and it may include a vertical portion 321 and a convex portion 322 connected to the vertical portion 321. The limiting surface 323 may be an inclined surface, which extends obliquely from the side of the vertical portion 321 of one packing key 32 facing the vertical portion 321 of the other packing key 32 to the bottom surface of the convex portion 322 of the one packing key 32.

[0058] Among them, the upper end of the vertical portion 321 can extend into the notch 222, and the convex portion 322 is used to be clamped into the clamping position 2211. The transverse dimension of the convex portion 322 is similar to the transverse dimension of the clamping position 2211, so that the convex portion 322 can be fixed to the clamping position 2211 in an interference fit manner.

[0059] Preferably, the thickness of the packing key 32 may be the same as that of the plate-shaped main body 311, both being half of the thickness of the limiting groove 221.

[0060] Preferably, a connecting portion is provided at the top of the positioning portion 3311 of the split filling block 331; the connecting portion is a threaded hole that does not penetrate through the positioning portion 3311, or the connecting portion is a snap ring of the split filling block 331. The threaded hole facilitates subsequent extraction of the split filling block 331 from the notch 222 out of the limiting groove 221 by means of a puller 7.

[0061] Combined with Figures 11 to 13 , the split filling block 331 may include a positioning portion 3311 and two deformation portions 3312 extending downward from the positioning portion 3311. A positioning groove is formed between the two deformation portions 3312 for sleeving downward on the outer periphery of the wedge block 332 from the upper end of the wedge block 332. Preferably, the above-mentioned threaded hole or snap ring is provided on the positioning portion 3311. In some embodiments, the depth of the positioning portion 3311 is approximately 8 mm, and the thickness of the threaded hole is approximately 5 - 7 mm. Preferably, the thickness of the threaded hole is 5 mm.

[0062] Preferably, the upper end of the wedge block 332 is a clamping block, and the upper end of the positioning groove may be a clamping groove, and the clamping groove is clamped on the clamping block to form a pre-fixation between the split filling block 331 and the wedge block 332.

[0063] Preferably, the axial positioning key 31, the packing key 32, the split filling block 331, and the wedge block 332 can all be made of metal materials such as stainless steel or aluminum alloy.

[0064] The application of the final stage blade closing axial locking device 3 is as follows:

[0065] Before installing the last blade 1, first push the axial positioning key 31 into the limit groove 221 in the circumferential direction from the limit groove 221, and then install the last blade 1. Push the blade 1 into the wheel groove A. After the blade 1 is pushed into the working position, push the axial positioning key 31 in the circumferential direction towards the blade 1 so that the protrusion 312 of the axial positioning key 31 is stuck in the groove 111. Install two packing keys 32. You can use needle-nose pliers to put the two packing keys 32 into the limit groove 221 in the radial direction, and then you can use an extension rod to fix the two packing keys 32 in the axial direction of the hub 2 back and forth to the designated position (such as two positions 2211). Place the split filling assembly 33 downwards from the notch 222 into the limit groove 222 and in the gap formed between the two packing keys 32. You can use an extended chisel head to knock the split filling block 331 into the limit groove 221 from the notch 222. The split filling block 331 deforms under the action of the wedge block 332 to tightly press against the two packing keys 32, and clamp the entire last-stage blade closing axial locking device 3 in the limit groove 221, thereby fixing the blade 1 in the wheel groove A.

[0066] When it is necessary to remove the last-stage blade closing axial locking device 3, first remove the split filling assembly 33 from the limit groove 221 through the notch 222, and then take out the two packing keys 32. At this time, the axial positioning key 31 can be pushed from the first space to the second space so that the protrusion 312 is disengaged from the groove 111, and the blade 1 can be disengaged from the wheel groove A.

[0067] It can be understood that the split filling block 331 of the split filling assembly 33 deforms under force to fix the packing key 32, and further fixes the axial positioning key 31 to lock the blade 1 on the hub 2. When it is necessary to disassemble the blade 1, only the split filling block 331 needs to be taken out, such as connecting to the threaded hole at the top of the split filling block 331 through the puller 7, and then sequentially taking out the packing key 32 and the axial positioning key 31. This disassembly process does not require using tools to drill relevant components, ensuring that the hub 2 will not be damaged, and can effectively save the maintenance work period of the last-stage blade.

[0068] The present invention also discloses a method for disassembling and assembling a last-stage blade closing axial locking device, which is applied to the last-stage blade closing axial locking device 3 described in any of the above embodiments, and includes an installation step and a removal step. The installation step includes:

[0069] A1: Install the axial positioning key 31 into the first space of the limit groove 221, and push the axial positioning key 31 circumferentially to fit the protrusion 312 into the groove 111 at the root 11 of the blade 1.

[0070] A2: Install the two packing keys 32 into the second space of the limiting groove 221 from the notch 222 respectively, with a predetermined gap between the two packing keys 32. Then install the split filling component 33 into the predetermined gap, and apply a radially inward force to the positioning portion 3311 of the split filling block 331, so that the split filling block 331 deforms along the wedge block 332 to press against the two packing keys 32.

[0071] Preferably, in A1, before installing the last blade 1, first push the axial positioning key 31 into the limiting groove 221 in the circumferential direction of the limiting groove 221, so that the circumferential wall surface of the protrusion 312 of the axial positioning key 31 is flush with the plane of the circumferential wall surface of the limiting groove 221, that is, the protrusion 312 does not protrude from the limiting portion 22 so as not to hinder the installation path of the blade 1. Push the last blade 1 into the installation position in the wheel groove A, and push the axial positioning key 31 circumferentially into the blade, so that the protrusion 312 is stuck in the groove 111 of the blade 1.

[0072] In A2, put the two packing keys 32 into the limiting groove 221 from the notch 222 in the radial direction, and then the two packing keys 32 can be fixed back and forth in the axial direction of the hub 2 using an extension rod or a hairpin and installed at the designated positions (such as the two positions 2211).

[0073] Preferably, in A2, use an extended chisel head 4 to apply force to the split filling block 331. Further, the split filling block 331 and the wedge block 332 can be temporarily fixed together, and use the extended chisel head 4 (as Figure 14 shown) to knock the split filling block 331 into the gap between the two packing keys 32 in the limiting groove 221, so that the cross section of the split filling block 331 is flush with the two packing keys 32, the split filling block 331 splits and deforms, catches the wedge block 332, and the two deformed portions 3312 of the split filling block 331 press against the limiting surfaces 323 of the two packing keys 32 to complete the installation.

[0074] Further, the removal step may include:

[0075] S1: Connect the top of the split filling block 331 using a pulling tool, and apply a radially outward force to the positioning portion 3311 at the top of the split filling block 331 to pull the split filling block 331 out of the limiting groove 221 from the notch 222;

[0076] S2: Take out the wedge block 332 and the two packing keys 32 in sequence;

[0077] S3: Push the axial positioning key 31 circumferentially to make the protrusion 312 disengage from the root 11 of the blade 1, push the blade 1 axially out along the wheel groove A, remove the blade 1, and remove the axial positioning key 31 to complete the removal.

[0078] Among them, in S1, the pulling tool needs to form a connection with the top end of the positioning part 3311 to apply force to the positioning part 3311. Here, a connection part can be provided at the top of the positioning part 3311. The form of the connection part is not limited, and the form of the pulling tool is also not limited, as long as a connection relationship facilitating force application can be formed between the two.

[0079] Optionally, the said pulling tool can be a pin extractor 7 (as shown in Figure 17 and Figure 18 ), and the connection part can be a threaded hole, and the pin extractor 7 is used to connect to the threaded hole.

[0080] Optionally, in step S1: Use the pin extractor 7 to connect to the threaded hole at the top of the positioning part 3311, and pull out the split filling block 331 from the notch 222 out of the limiting groove 221.

[0081] Preferably, in S1, use an extended center punch 5 (as shown in Figure 15 ) to punch a center punch point at the middle position of the split filling block 331, use an extended drill bit 6 (as shown in Figure 16 ) to drill a hole, drill to the top position of the wedge block 332, use a tap to tap a threaded hole in the hole to form a threaded hole, and then use the pin extractor 7 to pull out the split filling block 331. Preferably, the extended drill bit 6 can be a 4.5 mm extended drill bit. Preferably, in S2, use a magnetic bar to suck out the wedge block 332.

[0082] Preferably, in S2, use an extended chisel 8 to move one of the packing keys 32 to the relative position of the notch 222 of the limiting groove 221, use a pair of needle-nose pliers to take out the packing key 32, and then take out the other packing key 32.

[0083] In an alternative embodiment, in the above S1, the threaded hole machined at the middle position of the split filling block 331 can be replaced by a threaded hole pre-formed on the top surface of the split filling block 331. That is, the threaded hole is a prefabricated hole. For example, when machining and preparing the split filling block 331, a threaded hole can be machined at the top of the split filling block 331. The threaded hole can be non-through, which ensures the overall strength of the split filling block 331 and at the same time provides a sufficient connection distance between the pin extractor 7 and the threaded hole.

[0084] Or, in other alternative embodiments, the above connection part can be a snap ring structure such as a pull ring, a lifting ring, or a clamping ring pre-formed on the top surface of the split filling block 331 for snap-fitting with the pulling tool. In addition, the connection part can also be a protruding structure formed by a part of the positioning part 3211 extending axially or circumferentially outward. More forms will not be exemplified here.

[0085] Compared with the traditional process, the disassembly and assembly method of the last-stage blade closed axial locking device of the present invention has the following beneficial effects:

[0086] Adopt the end-stage blade closed axial locking device 3 to improve the disassembly and assembly process of the closed axial positioning key in the related technology. When removing the axial positioning key, it is no longer necessary to destructively drill and remove the packing key. Even if the packing key 32 is not drilled cleanly, the removal of the axial positioning key can still be completed. It is no longer necessary to drill cleanly. Retain a certain part of the split filling block. The drill bit has a certain safety distance from the blade 1 and the wheel groove A of the hub 2 both axially and radially, ensuring that the blade 1 and the wheel groove A of the hub 2 will no longer be damaged during the removal process.

[0087] Currently, the maintenance cycle of the end-stage blades is 4C. There are a large number of end-stage blade maintenance tasks every year, and the end-stage blade maintenance work is on the main critical path of the conventional island.

[0088] 1. The application of this invention can ensure that the blade 1 and the wheel groove A will no longer be damaged when removing the end-stage blade closed axial locking device, ensuring the safety and quality of the unit equipment.

[0089] 2. Through the process improvement of this invention, the requirements for the experience and proficiency of operators can be reduced.

[0090] 3. It can greatly save the construction period of the removal work of the end-stage blade closed axial locking device, save about 2 hours on the critical path, and can avoid the jamming caused by the incomplete drilling of the traditional closed axial positioning key, avoiding additional construction period losses, and greatly ensuring the construction period of saving the critical path.

[0091] It can be understood that the above embodiments only represent the preferred embodiments of the present invention. The description is relatively specific and detailed, but it cannot be understood as a limitation to the scope of the invention patent of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, the above technical features can be freely combined, and several deformations and improvements can also be made, which all belong to the protection scope of the present invention. Therefore, all equivalent transformations and modifications made to the scope of the claims of the present invention shall fall within the scope covered by the claims of the present invention.

Claims

1. An end-stage blade closed axial locking device for locking a blade (1) on a hub (2). The hub (2) is provided with a plurality of bosses (21) arranged at intervals in the circumferential direction. A wheel groove (A) is formed between two adjacent bosses (21) for installing the root (11) of the blade (1). A limiting portion (22) is provided at the top of each boss (21). A limiting groove (221) that is radially and circumferentially through is provided between the upper surface of the limiting portion (22) and the upper surface of the boss (21). The axial dimension of the top of the limiting groove (221) is relatively reduced to form a notch (222). The limiting groove (221) and the notch (222) penetrate the opposite side surfaces of the limiting portion (22) in the circumferential direction. The limiting groove (221) is divided into a first space and a second space arranged in the circumferential direction. A groove (111) is provided on one side of the root (11) facing the limiting groove (221). It is characterized in that, The last-stage blade closing axial locking device includes: An axial positioning key (31) for installation in the first space. The axial positioning key (31) includes a plate-shaped main body (311). A protrusion (312) is provided on one side of the plate-shaped main body (311) facing the groove (111) for extending into the groove (111). Two packing keys (32) for installation in the second space. A predetermined gap is provided between the opposite sides of the two packing keys (32). A split filling assembly (33) for installation in the predetermined gap. The split filling assembly (33) includes a split filling block (331) and a wedge block (332). The split filling block (331) includes a positioning portion (3311) and a deformation portion (3312) for sleeving on the wedge block (332). The deformation portion (3312) can axially deform along the wedge block (332) under the action of a radial external force to abut against the two packing keys (32). The two packing keys (32) further abut against the inner walls on both sides of the second space and are fixed in the second space to limit the axial positioning key (31), thereby locking the blade (1) on the hub (2).

2. The last-stage blade closing axial locking device according to claim 1, characterized in that, A connecting portion is provided at the top of the positioning portion (3311). The connecting portion is a threaded hole that does not penetrate the positioning portion (3311), or the connecting portion is a snap ring.

3. The end-stage blade closed axial locking device according to claim 1, wherein Limit surfaces (323) are respectively provided on the opposite sides of the two packing keys (32). The limit surfaces (323) are rectangular inclined surfaces that extend obliquely downward and away from the split filling assembly (33). Wherein, the deformation portion (3312) abuts against the limit surface after deformation.

4. The last-stage blade closing axial locking device according to claim 1, characterized in that, The cross-sectional shape of the plate-shaped main body (311) is a T-shaped structure. The cross-sectional shape of the limit groove (221) is a T-shaped structure.

5. The last-stage blade closing axial locking device according to any one of claims 1 to 4, characterized in that The thickness of the plate-shaped main body (311) is half of the depth direction of the limit groove (221), and the depth direction is the circumferential direction.

6. A disassembly and assembly method for the axial locking device of the last-stage blade enclosure, which is applied to the axial locking device of the last-stage blade enclosure according to any one of the above claims 1 to 5, characterized in that, It includes an installation step and a removal step. The installation step includes: A1: Install the axial positioning key (31) into the first space of the limit groove (221), and axially push the axial positioning key (31) to install the protrusion (312) into the groove (111) at the root (11) of the blade (1). A2: Install the two packing keys (32) into the second space of the limit groove (221) from the slot opening (222) respectively, and a predetermined gap is provided between the two packing keys (32). Then install the split filling assembly (33) into the predetermined gap, and apply a radial inward force to the positioning portion (3311) of the split filling block (331) to deform the split filling block (331) along the wedge block (332) to abut against the two packing keys (32). The removal step includes: S1: Connect the top of the split packing block (331) using a pulling tool, and apply a radially outward force to the positioning portion (3311) at the top of the split packing block (331) through the pulling tool to pull the split packing block (331) out of the limiting groove (221) from the notch (222). S2: Sequentially take out the wedge block (332) and the two packing keys (32). S3: Push the axial positioning key (31) circumferentially to disengage the protrusion (312) from the root (11) of the blade (1), axially push the blade (1) along the wheel groove (A), remove the blade (1), and then remove the axial positioning key (31) to complete the disassembly.

7. The disassembly and assembly method of the end-stage blade closed axial locking device according to claim 6, characterized in that, In S1: Connect the threaded hole at the top of the positioning portion (3311) using a pin extractor (7) to pull the split packing block (331) out of the limiting groove (221) from the notch (222).

8. The method for disassembling and assembling the axial locking device for closing the last-stage blade according to claim 7, characterized in that, In S1, use an extended center punch (5) to punch a center punch mark at the middle position of the split packing block (331), use an extended drill bit (6) to drill a hole until reaching the top position of the wedge block (332), and use a tap to tap a threaded hole in the hole to form the threaded hole. Alternatively, the threaded hole is a prefabricated hole.

9. The disassembly and assembly method of the axial locking device for the last-stage blade enclosure according to claim 6, characterized in that, In S2, use a magnetic bar to suck out the wedge block (332) from the notch (222).

10. The method for disassembling and assembling the end-stage blade closing axial locking device according to claim 6, characterized in that, In S2, use an extended chisel (8) to move one of the packing keys (32) to the relative position of the notch (222) of the limiting groove (221), use a pair of needle-nose pliers to take out the packing key (32), and then take out the other packing key (32).

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