An assembly tool and method for installing an impeller assembly

Abstract

The application relates to the technical field of assembly tools, and discloses an assembly tool and an assembly method for installing an impeller assembly. The assembly tool comprises an inner sleeve, an outer sleeve assembly and a locking nut. The inner sleeve is used for being installed on a pull rod of the impeller assembly, and an outer side wall of the inner sleeve is provided with at least one outer annular protrusion. The outer sleeve assembly is sleeved on the outer side of the inner sleeve, and comprises two matched half-circle sleeves. At least one inner annular groove is arranged on the inner wall of the half-circle sleeve, the inner annular groove corresponds to the outer annular protrusion, and the upper end surface of the outer sleeve assembly constitutes a supporting stress surface. The locking nut is used for being screwed on the pull rod of the impeller assembly, the inner sleeve is located between the locking nut and the impeller of the impeller assembly, and is used for axially fixing the impeller. The outer annular protrusion of the inner sleeve is accurately matched with the inner annular groove of the half-circle sleeve of the outer sleeve assembly, the upper end surface of the outer sleeve assembly provides a stable supporting stress surface for a bolt tensioner, ensures that the bolt tensioner can smoothly exert a pulling force, and meets the strict requirement of the impeller pull rod on the pre-tightening force.

Description

Technical Field

[0001] This invention relates to the field of assembly tooling technology, and more specifically to an assembly tooling and assembly method for installing impeller assemblies. Background Technology

[0002] In high-speed rotating machinery such as centrifugal compressors, the rotor assembly, as a core functional component, directly determines the overall reliability, safety, and service life of the machine through its assembly quality. The impeller, as a key working element of the rotor assembly, is typically connected to the main shaft via a tie rod and secured by a locking nut with strong preload to ensure the impeller maintains a firm axial and radial position with the main shaft under high-speed rotation and complex load conditions. Therefore, the tension of the impeller tie rod (i.e., the preload of the locking nut) is a process parameter that must be strictly controlled during assembly—insufficient preload may lead to impeller loosening, increased vibration, or even runaway accidents; while excessive preload may damage the tie rod threads or impeller mating surfaces, causing stress corrosion or fatigue fracture risks, seriously affecting the compressor's safety, quality, and product reliability.

[0003] Currently, the industry commonly uses bolt tensioning to achieve precise control of tie rod preload. This method involves applying a controllable axial tensile load to the tie rod using a bolt tensioner. Once the tie rod elastically elongates to the target value, the lock nut is tightened to release the tension, thus utilizing the elastic recoil of the tie rod to obtain a precise preload. This method offers significant advantages such as high preload accuracy, good operational repeatability, and minimal wear on the threaded joints, and is considered the preferred process for high-precision bolt connections.

[0004] However, in practical engineering applications, the proper use of bolt tensioners relies on a sufficiently large support area and axial operating space. The bolt tensioner needs to be stably mounted on the impeller end face or a dedicated support structure, and the length of the tie rod extending beyond the nut must meet the clamping requirements of the tensioner and the stroke requirements of the hydraulic cylinder. However, in compact compressor designs, due to limitations in aerodynamic performance optimization and overall size constraints, the impeller end face is often quite narrow, resulting in a very limited effective support area for placing the bolt tensioner. Traditional bolt tensioners often cannot be installed or properly applied. If the tightening requirements are lowered due to the inability to use bolt tensioners, it will directly reduce the reliability and fatigue durability of the impeller connection, thus affecting the overall quality of the compressor at the time of manufacture.

[0005] Therefore, how to achieve high-precision and controllable fastening of the impeller tie rod under limited support area and confined space has become a technical problem that urgently needs to be solved in the current compressor assembly process. Summary of the Invention

[0006] This invention addresses the existing technical problems by providing an assembly fixture and assembly method for installing impeller assemblies.

[0007] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: an assembly tool for installing an impeller assembly, comprising an inner sleeve, an outer sleeve assembly and a locking nut; The inner sleeve is used to be installed on the tie rod of the impeller assembly, and the outer side wall of the inner sleeve is provided with at least one outer annular protrusion; The outer sleeve assembly is fitted onto the outside of the inner sleeve. The outer sleeve assembly includes two mating semicircular sleeves. The inner wall of the semicircular sleeve is provided with at least one inner annular groove, which corresponds to the outer annular protrusion. The upper end face of the outer sleeve assembly forms a supporting force-bearing surface. The locking nut is used to screw onto the pull rod of the impeller assembly, and the inner sleeve is located between the locking nut and the impeller of the impeller assembly for axially fixing the impeller.

[0008] Based on the above technical solution, the present invention can be further improved as follows: Preferably, it further includes a bolt tensioner for mounting on the tie rod of the impeller assembly, the bolt tensioner being in contact with the support surface of the outer casing assembly.

[0009] Preferably, one end of the inner sleeve along the axial direction is a positioning and fitting section, which is located on the side close to the impeller and is in the shape of a hollow cylinder.

[0010] Preferably, each of the semicircular sleeves has lugs at both ends, and locating pins and locking screws are installed on the lugs.

[0011] Preferably, one of the semicircular sleeves has a set screw hole on its lug.

[0012] Preferably, the locking nut is cylindrical, and at least one auxiliary hole is provided on the side wall of the locking nut.

[0013] Preferably, the outer surface of the locking nut is provided with an anti-slip structure.

[0014] The beneficial effects of this invention are as follows: By using a separate design for the inner and outer sleeve assemblies, this invention solves the problem of limited impeller installation space. The inner sleeve acts directly on the impeller, and its outer annular protrusion precisely matches the inner annular groove of the outer sleeve assembly. This achieves both rapid positioning and reliable connection, while the upper surface of the outer sleeve assembly provides a stable support surface for the bolt tensioner, ensuring that the bolt tensioner can smoothly apply tension and meet the stringent preload requirements of the impeller tie rod. The two semicircular sleeves are quickly assembled and locked using locating pins and locking screws, making installation and disassembly convenient and improving assembly efficiency. Simultaneously, the locating mating section of the inner sleeve is designed as a hollow cylindrical structure, forming a small clearance fit with the inner hole of the outer sleeve assembly, ensuring coaxiality and stability during installation. The auxiliary hole on the locking nut facilitates tightening the locking nut with tools, and the anti-slip structure increases friction during operation, preventing slippage. The setting of the set screw hole allows the outer sleeve assembly to be disassembled by applying a pushing force to the opposite semicircular sleeve through the set screw, thereby separating the outer sleeve assembly from the inner sleeve and avoiding the problem of difficulty in disassembly due to excessive tightness. Overall, the assembly fixture of the present invention has a compact structure and is easy to operate, effectively improving the installation quality and efficiency of the impeller assembly and ensuring the safety performance and product quality of the compressor.

[0015] This invention also discloses an assembly method for installing an impeller assembly, using the assembly fixture for installing the impeller assembly described above, including the following steps: S1: Install the inner sleeve on the tie rod of the impeller assembly, with the positioning and mating section of the inner sleeve close to the impeller assembly; S2: Install the outer sleeve assembly onto the inner sleeve. The two are positioned and locked by the outer annular protrusion and the inner annular groove. S3: Screw the locking nut onto the pull rod so that the end face of the locking nut near the auxiliary hole contacts the upper surface of the outer sleeve assembly; S4: Install the bolt tensioner onto the tie rod and lock nut, with the lower end face of the bolt tensioner abutting against the support force-bearing surface of the outer sleeve assembly; S5: Use the bolt tensioner to stretch the tie rod, and tighten the lock nut to the upper end face of the inner sleeve while it is stretched. S6: Disassemble the bolt tensioner and outer sleeve assembly to complete the assembly.

[0016] Preferably, in step S2, the inner annular grooves of the two semicircular sleeves are first engaged on the outer annular protrusion of the inner sleeve, then the positioning pins are installed to complete the positioning of the two semicircular sleeves, and finally the locking screws are installed to lock the two semicircular sleeves.

[0017] Preferably, in step S6, a set screw is screwed into the set screw hole of the outer sleeve assembly, and the thrust generated by the set screw is used to separate the outer sleeve assembly from the inner sleeve.

[0018] The beneficial effects of the assembly method of this invention are as follows: The assembly method of this invention can efficiently and accurately complete the installation of the impeller assembly. First, the separate installation design of the inner and outer sleeve assemblies allows for the stable installation of the inner sleeve on the tie rod and its engagement with the impeller in space-constrained impeller installation environments. Then, the combination of the two semi-circular sleeves quickly forms a support structure, solving the problem of insufficient support space for the bolt tensioner in traditional methods. Second, the assembly steps are logically clear. From inner sleeve positioning and outer sleeve assembly locking, to locking nut tightening, bolt tensioner installation and tensioning, and finally disassembly, each step is closely connected, ensuring standardized and reliable operation. The entire assembly method is convenient to operate and the process is controllable. It not only significantly improves the assembly efficiency of the impeller assembly but also ensures assembly quality, meeting the compressor's stringent requirements for impeller tie rod tension, thereby improving the overall safety performance and product reliability of the compressor. Attached Figure Description

[0019] Figure 1 This is a three-dimensional schematic diagram of the inner sleeve of the present invention; Figure 2 This is a cross-sectional schematic diagram of the inner sleeve of the present invention; Figure 3 This is a schematic diagram of the outer casing assembly of the present invention; Figure 4 This is a cross-sectional schematic diagram of the outer casing assembly of the present invention; Figure 5 This is a three-dimensional schematic diagram of the locking nut of the present invention; Figure 6 This is a cross-sectional schematic diagram of the locking nut of the present invention; Figure 7 This is a schematic diagram of the impeller of the present invention; Figure 8 This is a schematic diagram of the inner sleeve of the present invention installed on the tie rod; Figure 9 This is a schematic diagram of the outer sleeve assembly of the present invention installed on the inner sleeve; Figure 10 This is a schematic diagram of the locking nut of the present invention installed on the tie rod; Figure 11 This is a schematic diagram of the bolt tensioner of the present invention installed on the tie rod; Figure 12 This is a cross-sectional view of the bolt tensioner of the present invention installed on the tie rod; Figure 13 This is a schematic diagram of the completed assembly of the present invention.

[0020] The reference numerals in the attached drawings are as follows: 10, inner sleeve; 11, outer annular protrusion; 20, outer sleeve assembly; 21, semi-circular sleeve; 22, inner annular groove; 23, locating pin; 24, locking screw; 25, set screw hole; 30, locking nut; 31, auxiliary hole; 40, impeller assembly; 41, tie rod; 42, impeller; 43, rotor shaft; 50, bolt tensioner; 51, pull head; 52, support component. Detailed Implementation

[0021] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0022] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. The terms "vertical," "upper," "lower," "horizontal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention.

[0023] like Figures 1 to 13 As shown, the present invention discloses an assembly fixture for installing an impeller assembly, including an inner sleeve 10, an outer sleeve assembly 20, and a locking nut 30; The inner sleeve 10 is used to be installed on the pull rod 41 of the impeller assembly 40. The inner diameter of the inner sleeve 10 corresponds to the outer diameter of the pull rod 41, and the outer diameter of the inner sleeve 10 corresponds to the outer diameter of the locking nut 30, which facilitates processing and assembly. The outer wall of the inner sleeve 10 is provided with at least one outer annular protrusion 11. The number of outer annular protrusions 11 is determined according to the tensile force requirements and the size limitation of the inner sleeve 10. In this embodiment, four outer annular protrusions 11 are evenly provided along the axial direction. One end of the inner sleeve 10 along the axial direction is a positioning and fitting section. The positioning and fitting section is located on the side close to the impeller 42. The outer surface of the positioning and fitting section is a smooth cylindrical surface. The outer sleeve assembly 20 is fitted onto the outside of the inner sleeve 10. The outer sleeve assembly 20 includes two mating semi-circular sleeves 21. The inner wall of the semi-circular sleeve 21 is provided with at least one inner annular groove 22. The inner annular groove 22 corresponds to the outer annular protrusion 11. The upper end face of the outer sleeve assembly 20 forms a supporting force-bearing surface. The locking nut 30 is used to screw onto the pull rod 41 of the impeller assembly 40, and the inner sleeve 10 is located between the locking nut 30 and the impeller 42 of the impeller assembly 40 for axially fixing the impeller 42.

[0024] In use, when the locking nut 30 is tightened on the pull rod 41, its lower end face presses against the upper end face of the inner sleeve 10. The inner sleeve 10 then transmits axial force to the impeller 42, thereby firmly fixing the impeller 42 to the rotor shaft 43, ensuring the stability and reliability of the impeller assembly 40 during high-speed rotation. Specifically, the positioning section of the inner sleeve 10 precisely matches the inner hole of the semi-circular sleeve 21, ensuring the coaxiality of the outer sleeve assembly 20 and the inner sleeve 10. The tightening of the locking nut 30 provides the necessary axial preload, preventing the impeller 42 from axially shifting or loosening during operation. This method of indirectly transmitting force through the inner sleeve 10 avoids potential damage caused by direct contact between the locking nut 30 and the impeller 42, while also making the force transmission more uniform, which is beneficial for protecting components such as the impeller 42.

[0025] Each of the semicircular sleeves 21 has lugs at both ends, and locating pins 23 and locking screws 24 are installed on the lugs to achieve precise positioning and reliable connection of the two semicircular sleeves 21. When installing the outer sleeve assembly 20, the inner annular grooves 22 of the two semicircular sleeves 21 are first engaged with the outer annular protrusions 11 of the inner sleeve 10. At this time, by aligning the locating pin holes on the lugs and inserting the locating pins 23, the relative positions of the two semicircular sleeves 21 can be quickly determined, ensuring the fitting accuracy between the inner annular grooves 22 and the outer annular protrusions 11, and avoiding misalignment that would affect the support stability. After positioning, locking screws 24 are installed and tightened through the locking screw holes on the lugs, so that the two semicircular sleeves 21 fit tightly together to form a complete annular outer sleeve structure, thereby firmly fixing the outer sleeve assembly 20 to the inner sleeve 10. This provides a stable support base for the subsequent bolt tensioner 50, preventing the outer sleeve assembly 20 from loosening or shifting during the tensioning process, and ensuring the safety and reliability of the entire assembly process.

[0026] Furthermore, one of the semicircular sleeves 21 has a set screw hole 25 on its lug. When it is necessary to disassemble the outer sleeve assembly 20, a set screw can be screwed into the set screw hole 25. The thrust generated between the set screw and the lug of the other semicircular sleeve 21 separates the two semicircular sleeves 21, thereby separating the outer sleeve assembly 20 from the inner sleeve 10. Specifically, after assembly, the outer sleeve assembly 20 and the inner sleeve 10 may be difficult to remove directly due to tight fit or a certain clamping force under tension. At this time, the set screw is screwed into the set screw hole 25. The end of the set screw will abut against the lug of the other semicircular sleeve 21. As the set screw is continuously screwed in, the thrust generated will force the other semicircular sleeve 21 to move radially outward, thereby overcoming the friction and clamping force between the outer sleeve assembly 20 and the inner sleeve 10, achieving easy separation of the two. This avoids damage to the tooling or impeller assembly 40 that may be caused by forced disassembly, and improves the convenience and safety of the disassembly operation. In this embodiment, the lugs on both sides of the semicircular sleeve 21 are provided with set screw holes 25 to ensure that the thrust is applied evenly to the other semicircular sleeve 21, thereby improving the stability and convenience of operation.

[0027] The outer side of the locking nut 30 is cylindrical, and at least one auxiliary hole 31 is provided on the side wall of the locking nut 30. The length of the auxiliary hole 31 is less than the wall thickness of the locking nut 30 to avoid damaging the pull rod 41. The auxiliary hole 31 is a round hole or a threaded hole. When it is necessary to assist in tightening or loosening the locking nut 30, an auxiliary tool (such as a bolt or lever) can be inserted into the auxiliary hole 31, and torque can be applied by turning the auxiliary tool, thereby operating the locking nut 30 more effortlessly and stably, ensuring that the locking nut 30 can be precisely tightened to the specified position.

[0028] In this embodiment, four auxiliary holes 31 are provided circumferentially on the side wall of the locking nut 30, and the included angle between adjacent auxiliary holes 31 is 90 degrees. This arrangement allows force to be applied from different directions when using auxiliary tools, making it easier for operators to select a suitable operating position according to the on-site space conditions and improving the flexibility of operation.

[0029] The outer surface of the locking nut 30 is provided with an anti-slip structure. This effectively increases the friction between the operator's hand or tool and the outer surface of the locking nut 30, thereby significantly reducing the risk of slippage during tightening or loosening of the locking nut 30. Furthermore, the stable friction helps the operator to more precisely control the tightening degree of the locking nut 30, ensuring the desired pre-tightening effect is achieved, thus guaranteeing the installation quality of the impeller assembly 40.

[0030] In this embodiment, the outer surface of the locking nut 30 is knurled to further enhance the anti-slip effect. The knurling is distributed in a regular concave-convex pattern on the outer circumferential surface of the locking nut 30. When the operator holds it directly by hand or clamps it with tools such as wrenches, the knurled structure can generate stronger friction with the hand or the inner wall of the tool, effectively preventing the hand or tool from sliding relative to the locking nut 30 during the application of force. This ensures that the operator can apply torque stably, which not only improves the safety of operation and avoids hand sprains or tool damage to equipment due to slippage, but also ensures that the locking nut 30 can be tightened or loosened accurately and reliably. This ensures that the preload is accurately applied to the impeller assembly 40 during installation, thus ensuring the installation quality of the impeller assembly 40.

[0031] The assembly fixture also includes a bolt tensioner 50, which is used to install on the pull rod 41 of the impeller assembly 40. The pull rod 41 has external threads, and the pull head 51 of the bolt tensioner 50 is connected to the pull rod 41 through a threaded hole. The bolt tensioner 50 is in contact with the support surface of the outer sleeve assembly 20, and its lower end face abuts against the support surface of the outer sleeve assembly 20. During operation, it can apply an upward tensile force to the pull rod 41, causing the pull rod 41 to elastically elongate. At this time, the locking nut 30 can be easily tightened to the upper end face of the inner sleeve 10 while the pull rod 41 is in the tensile state. When the bolt tensioner 50 is unloaded, the pull rod 41 will contract due to elastic recovery, thereby applying a continuous preload force to the locking nut 30 and the inner sleeve 10, ensuring that the impeller 42 is firmly fixed on the rotor shaft 43, meeting the strict requirements of the compressor for the tension of the pull rod 41. Compared to the traditional torque tightening method, this method of using bolt tensioner 50 for pre-tightening can more accurately control the magnitude of the pre-tightening force, avoid pre-tightening force errors caused by factors such as changes in the coefficient of friction, and greatly improve the installation accuracy and reliability of the impeller assembly 40.

[0032] This invention also discloses an assembly method for installing an impeller assembly, using the assembly fixture described above for installing the impeller assembly, including the following steps: S1: First, the tie rod 41 is threaded onto the rotor shaft 43. The impeller 42 is then fitted onto the tie rod 41, with the lower surface of the impeller 42 in contact with the upper end face of the rotor shaft 43. The inner sleeve 10 is then installed onto the tie rod 41 of the impeller assembly 40. The positioning and fitting section of the inner sleeve 10 is close to the impeller assembly 40, thereby ensuring that when other parts are installed later, there is a certain distance requirement between other parts and the impeller 42, avoiding damage to the impeller 42 and ensuring the quality of the impeller 42. S2: Install the outer sleeve assembly 20 onto the inner sleeve 10. The two are positioned and locked by the outer annular protrusion 11 and the inner annular groove 22. First, the inner annular grooves 22 of the two semicircular sleeves 21 are engaged on the outer annular protrusions 11 of the inner sleeve 10. Then, the positioning pins 23 are installed to complete the positioning of the two semicircular sleeves 21. Finally, the locking screws 24 are installed to lock the two semicircular sleeves 21. S3: Screw the locking nut 30 onto the pull rod 41 so that the end face of the locking nut 30 near the auxiliary hole 31 contacts the upper surface of the outer sleeve assembly 20, making it convenient to tighten the locking nut 30 through the auxiliary hole 31 later. S4: Install the bolt tensioner 50 onto the tie rod 41. Specifically, the pull head 51 of the bolt tensioner 50 has an internal thread, and the pull head 51 is connected to the tie rod 41 through the thread. A support member 52 is installed at the lower end of the bolt tensioner 50. The support member 52 has a receiving hole with a diameter larger than that of the locking nut 30. The locking nut 30 is located in the receiving hole. The support member 52 at the lower end of the bolt tensioner 50 abuts against the supporting force-bearing surface of the outer sleeve assembly 20 to ensure that the bolt tensioner 50 can apply tension to the tie rod 41 normally. The bolt tensioner 50 adopts existing technology.

[0033] S5: Operate the bolt tensioner 50 to stretch the tie rod 41. In the stretched state, tighten the lock nut 30 until it abuts against the upper end face of the inner sleeve 10. Specifically, the hydraulic tension generated by the bolt tensioner 50 stretches the tie rod 41 within its elastic range. The specific stretching length is calculated in advance according to the actual preload requirement. The magnitude of the hydraulic tension is set according to the required stretching length. In the stretched state, tighten the locking nut 30 so that it abuts against the upper end face of the inner sleeve 10. Specifically, the side wall of the receiving hole of the support member 52 is provided with a relief groove: when the position of the relief groove corresponds to the auxiliary hole 31 on the locking nut 30, the lever passes through the relief groove and is inserted into the auxiliary hole 31 to lock the locking nut 30; when the relief groove does not correspond to the auxiliary hole 31, since the outer side of the locking nut 30 is provided with an anti-slip structure such as a knurled structure, the lever acts on the outer side of the locking nut 30, rotates the locking nut 30 so that its auxiliary hole 31 corresponds to the relief groove, and then the lever acts on the auxiliary hole 31 to lock the locking nut 30. After the hydraulic pressure is released, the stretched rod 41 will have an elastic recovery tendency, but it has been locked by the locking nut 30, and this recovery force is converted into axial preload, thereby achieving the fastening installation of the impeller 42.

[0034] S6: Disassemble the bolt tensioner 50 and the outer sleeve assembly 20 to complete the assembly. When disassembly is difficult, screw the set screw into the set screw hole 25 of the outer sleeve assembly 20. Use the thrust generated by the set screw to separate the outer sleeve assembly 20 from the inner sleeve 10, while the inner sleeve 10 and the lock nut 30 are retained as part of the fixing structure.

[0035] This invention addresses the problem that the limited area of ​​the existing impeller 42 and tie rod 41 support surfaces affects the installation efficiency and quality of the impeller 42. By using this assembly fixture, an additional contact surface can be artificially added for the installation of the bolt tensioner 50, thereby enabling its use on impellers 42 of various sizes, improving the installation efficiency and quality of the impeller 42. The outer sleeve assembly 20 adopts the form of two semi-circular sleeves 21, further improving the convenience of installation and disassembly.

[0036] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An assembly method for installing an impeller assembly, employing an assembly fixture for installing the impeller assembly, characterized in that, The assembly fixture includes an inner sleeve (10), an outer sleeve assembly (20), and a locking nut (30). The inner sleeve (10) is used to be installed on the pull rod (41) of the impeller assembly (40). The outer side wall of the inner sleeve (10) is provided with at least one outer annular protrusion (11). One end of the inner sleeve (10) along the axial direction is a positioning and fitting section. The positioning and fitting section is located on the side close to the impeller (42). The positioning and fitting section is in the shape of a hollow cylinder. The outer sleeve assembly (20) is fitted onto the outside of the inner sleeve (10). The outer sleeve assembly (20) includes two mating semicircular sleeves (21). The inner wall of the semicircular sleeve (21) is provided with at least one inner annular groove (22). The inner annular groove (22) corresponds to the outer annular protrusion (11). The upper end face of the outer sleeve assembly (20) forms a supporting force surface. Each semicircular sleeve (21) has lugs at both ends. The lugs are equipped with positioning pins (23) and locking screws (24). One of the semicircular sleeves (21) has a set screw hole (25) on its lug. The locking nut (30) is used to screw onto the pull rod (41) of the impeller assembly (40). The inner sleeve (10) is located between the locking nut (30) and the impeller (42) of the impeller assembly (40). The inner diameter of the inner sleeve (10) corresponds to the outer diameter of the pull rod (41), and the outer diameter of the inner sleeve (10) corresponds to the outer diameter of the locking nut (30), for axially fixing the impeller (42). It also includes a bolt tensioner (50) for mounting on the tie rod (41) of the impeller assembly (40), and the bolt tensioner (50) is in contact with the support surface of the outer sleeve assembly (20); The assembly method includes the following steps: S1: Install the inner sleeve (10) on the tie rod (41) of the impeller assembly (40), with the positioning and mating section of the inner sleeve (10) close to the impeller assembly (40). S2: Install the outer sleeve assembly (20) onto the inner sleeve (10), and the two are positioned and locked by the outer annular protrusion (11) and the inner annular groove (22); S3: Screw the locking nut (30) onto the pull rod (41) so that the end face of the locking nut (30) near the auxiliary hole (31) contacts the upper surface of the outer sleeve assembly (20); S4: Install the bolt tensioner (50) onto the tie rod (41) and the lock nut (30), with the lower end face of the bolt tensioner (50) abutting against the support force surface of the outer sleeve assembly (20); S5: Use the bolt tensioner (50) to stretch the pull rod (41), and tighten the lock nut (30) to the upper end face of the inner sleeve (10) while it is stretched. S6: Disassemble the bolt tensioner (50) and the outer sleeve assembly (20) to complete the assembly.

2. The assembly method for installing the impeller assembly according to claim 1, characterized in that, The locking nut (30) is cylindrical, and at least one auxiliary hole (31) is provided on the side wall of the locking nut (30).

3. The assembly method for installing the impeller assembly according to claim 2, characterized in that, The outer surface of the locking nut (30) is provided with an anti-slip structure.

4. The assembly method for installing the impeller assembly according to claim 1, characterized in that, In step S2, the inner annular grooves (22) of the two semicircular sleeves (21) are first locked onto the outer annular protrusions (11) of the inner sleeve (10), then the positioning pins (23) are installed to complete the positioning of the two semicircular sleeves (21), and finally the locking screws (24) are installed to lock the two semicircular sleeves (21).

5. The assembly method for installing an impeller assembly according to claim 1, characterized in that, In step S6, a set screw is screwed into the set screw hole (25) of the outer sleeve assembly (20), and the thrust generated by the set screw is used to separate the outer sleeve assembly (20) from the inner sleeve (10).

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