Shaft end nut tightening tool

Abstract

The application relates to the technical field of turbine pump assembly, and provides a shaft end nut tightening tool. The shaft end nut tightening tool is applied to a turbine pump, the turbine pump is provided with a pump shaft, and the shaft end nut tightening tool is used for tightening a nut on the pump shaft; the shaft end nut tightening tool comprises a connecting shaft which is used for being connected with the pump shaft and serving as an installation reference; a shaft sleeve is sleeved on the connecting shaft, and an outer circumferential surface of the shaft sleeve forms a rotating support surface; a sliding sleeve comprises a sliding sleeve body which is annular and is sleeved outside the shaft sleeve; a positioning protrusion is arranged at one end of the sliding sleeve body which faces the pump shaft and is used for cooperating with a positioning clamping groove on the nut; and a sliding sleeve rod is connected to the outer circumferential surface of the sliding sleeve body and is used for driving the sliding sleeve body and the positioning protrusion to rotate. The shaft end nut tightening tool provided by the application can solve the problem of inconvenient installation of the shaft end nut of the turbine pump in the prior art.

Description

Technical Field

[0001] This application relates to the field of turbine pump assembly technology, and in particular to a tooling for tightening shaft end nuts. Background Technology

[0002] The turbopump is a core component of a liquid rocket engine and is known as the "heart" of the engine. The assembly precision of its rotor system directly determines the dynamic performance and operational reliability of the turbopump. The shaft end nut, as a key component in rotor assembly, is mainly used to tighten key parts such as bearings and impellers, and to provide precise axial preload for the entire rotor system. This preload is crucial for ensuring the correct bearing clearance, transmitting working torque, and ensuring the dynamic balance of the rotor at high speeds.

[0003] Currently, when tightening the nut on the shaft end of a turbine pump, the existing operating method usually requires three people to work together because the torque required to tighten the nut is relatively large. Two people use special tools to press the fixture firmly to counteract the huge reverse torque generated by the fixture when the torque is applied and to prevent it from slipping off the nut, while the third person operates a torque wrench to apply the torque and complete the tightening operation of the nut.

[0004] This existing assembly method has many problems. The huge reverse torque generated by the tooling during the application of torque can cause the tooling to vibrate violently. There is still a risk that the tooling will slip off the nut. Once the tooling slips off, it is very likely to scratch the nut, pump shaft thread or surrounding precision parts, causing irreversible damage. At the same time, the three-person collaborative operation is cumbersome and requires a high degree of coordination. This not only reduces the assembly efficiency, but also makes it impossible for a single person to perform a safe, efficient and high-precision tightening operation. There is a lack of dedicated tooling that integrates shaft locking and tightening functions, which makes it difficult to meet the high precision and high efficiency requirements of turbine pump rotor assembly. Summary of the Invention

[0005] This application provides a shaft end nut tightening tool to solve the problem of inconvenient installation of turbine pump shaft end nuts in the prior art.

[0006] According to a first aspect of this application, a shaft end nut tightening fixture is applied to a turbine pump, the turbine pump having a pump shaft, and the shaft end nut tightening fixture is used to tighten a nut onto the pump shaft. The shaft end nut tightening fixture includes: A connecting shaft is used to connect to the pump shaft and serves as an installation reference. A bushing is fitted onto the connecting shaft, and the outer circumferential surface of the bushing forms a rotational support surface; Sliding sleeve, including: The main body of the sliding sleeve is annular and is fitted onto the outside of the bushing; A positioning protrusion is provided at one end of the sliding sleeve body facing the pump shaft, for engaging with the positioning groove on the nut; A sliding rod is connected to the outer circumferential surface of the sliding sleeve body to drive the sliding sleeve body and the positioning protrusion to rotate.

[0007] According to one embodiment of this application, the pump shaft is provided with a positioning hole, the first end of the connecting shaft is inserted into the positioning hole, and the cross-sectional shape of the connecting shaft matches the positioning hole to restrict the relative rotation of the connecting shaft and the pump shaft.

[0008] According to one embodiment of this application, a guide portion is formed at the first end of the connecting shaft.

[0009] According to one embodiment of this application, a first rotating hole is provided at the end of the connecting shaft opposite to the pump shaft, and the first rotating hole is a blind hole; or The connecting shaft is provided with a second rotating hole that passes through it axially.

[0010] According to one embodiment of this application, the hollow region of the bushing matches the cross-sectional shape of the connecting shaft to restrict relative rotation between the bushing and the connecting shaft.

[0011] According to one embodiment of this application, the bushing is fixedly connected to the connecting shaft, so that the bushing is fixed in position on the connecting shaft.

[0012] According to one embodiment of this application, the free end of the sliding sleeve rod is provided with a rotating boss, and the rotation axis of the rotating boss is parallel to the rotation axis of the sliding sleeve body; The rotating boss rotates to drive the sliding sleeve body to rotate.

[0013] According to one embodiment of this application, the rotating boss is a hexagonal boss.

[0014] According to one embodiment of this application, the sliding sleeve body and the bushing are in a clearance fit.

[0015] According to one embodiment of this application, the positioning protrusions are configured as four, which are evenly arranged along the circumference of the sliding sleeve body.

[0016] The above-described one or more technical solutions in the embodiments of this application have at least one of the following technical effects: The shaft-end nut tightening fixture of this application connects the connecting shaft to the pump shaft as an installation reference, ensuring the relative fixation of the subsequent bushing and sliding sleeve positions. When the operator tightens the sliding sleeve, it rotates around the connecting shaft. Even if the torque applied by the operator has a certain angle with the horizontal plane (i.e., the plane perpendicular to the pump shaft), the connecting shaft's restraining effect allows the sliding sleeve to rotate on the horizontal plane, preventing the generation of an axial component force on the connecting shaft. This ensures that the positioning protrusion will not dislodge from the positioning slot, thus avoiding scratching the turbine pump. Furthermore, in the above operation, only one operator is needed to complete the nut tightening operation, eliminating the need for other personnel to assist in tightening the sliding sleeve or other components, thereby improving the nut installation efficiency.

[0017] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments or related technologies of this application, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of a turbopump in the prior art.

[0020] Figure 2 This is a structural diagram of a tightening tool in the prior art.

[0021] Figure 3 This is a schematic diagram of the shaft end nut tightening fixture provided in the embodiments of this application.

[0022] Figure 4 This is a schematic diagram of the structure of the bushing installed on the connecting shaft according to an embodiment of this application.

[0023] Figure 5 This is a schematic diagram of the structure of the sliding sleeve provided in the embodiment of this application.

[0024] Figure label: 1. Connecting shaft; 11. First rotating hole; 12. Limiting tooth; 2. Bushing; 3. Sliding sleeve; 31. Sliding sleeve body; 32. Positioning protrusion; 33. Sliding sleeve rod; 34. Rotating boss; 4. Turbine pump; 41. Pump shaft; 411. Locating hole; 42. Nut; 421. Locating slot; 5. Existing tightening tools. Detailed Implementation

[0025] The embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this application, but should not be used to limit the scope of this application.

[0026] In the description of the embodiments of this application, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application 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. Therefore, they should not be construed as limitations on the embodiments of this application. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0027] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.

[0028] In the embodiments of this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0029] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the embodiments of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0030] Turbopump 4 is used in liquid rocket engines. The structure of turbopump 4 is as follows: Figure 1 As shown, the existing tightening tool 5 is as follows Figure 2 As shown, it is used to tighten the nut 42 onto the pump shaft 41, but it is inconvenient to use and can easily scratch the surface of the turbine pump 4.

[0031] A shaft end nut tightening fixture according to an embodiment of the first aspect of this application, such as Figure 3 As shown, the shaft end nut tightening fixture is applied to the turbine pump 4, which has a pump shaft 41. The shaft end nut tightening fixture is used to tighten the nut 42 onto the pump shaft 41. The shaft end nut tightening fixture includes a connecting shaft 1, a bushing 2, and a sliding sleeve 3. The connecting shaft 1 is used to connect to the pump shaft 41 and serves as an installation reference. The bushing 2 is sleeved on the connecting shaft 1, and the outer circumferential surface of the bushing 2 forms a rotation support surface. The sliding sleeve 3 further includes a sliding sleeve body 31, a positioning protrusion 32, and a sliding sleeve rod 33. The sliding sleeve body 31 is annular and sleeved on the outside of the bushing 2. The positioning protrusion 32 is located at the end of the sliding sleeve body 31 facing the pump shaft 41 and is used to cooperate with the positioning groove 421 on the nut 42. The sliding sleeve rod 33 is connected to the outer circumferential surface of the sliding sleeve body 31 and is used to drive the sliding sleeve body 31 and the positioning protrusion 32 to rotate.

[0032] The shaft end nut tightening fixture is specifically designed for tightening the pump shaft 41 and nut 42 of the turbine pump 4, achieving precise assembly through the collaboration of multiple components. The connecting shaft 1, as the core reference component, provides a fixed installation reference for subsequent components after docking with the pump shaft 41, ensuring the coaxiality of all components. The bushing 2 is fitted onto the connecting shaft 1, and its outer circumference can be precision machined to form a smooth rotational support surface, providing a stable rotational carrier for the sliding sleeve 3. The sliding sleeve 3, through the cooperation of the sliding sleeve body 31 and the bushing 2, and the docking of the positioning protrusion 32 with the positioning groove 421 of the nut 42, achieves torque transmission. The sliding sleeve rod 33 serves as the operating component, allowing the operator to apply force, driving the sliding sleeve body 31 and the positioning protrusion 32 to rotate synchronously, thereby driving the nut 42 to tighten. The clear division of labor and close cooperation of each component ensure the stability of the assembly process.

[0033] The connecting shaft 1 acts as a positioning reference, ensuring the relative positions of the bushing 2 and the sliding sleeve 3. This guarantees that the sliding sleeve 3 rotates horizontally around the connecting shaft 1, preventing axial force even when applied at an angle. This effectively prevents the positioning protrusion 32 from dislodging, protecting the precision parts of the turbine pump 4. The smooth rotating support surface provided by the bushing 2 reduces friction during the rotation of the sliding sleeve 3, improving operational smoothness and reducing the risk of vibration. No multiple people are needed to tighten the tooling; a single person can complete the operation, significantly simplifying the process and improving assembly efficiency. Simultaneously, precise positioning ensures stable torque transmission during the tightening of the nut 42, guaranteeing accurate axial preload and contributing to improved assembly precision of the turbine pump 4 rotor system, ensuring its dynamic performance and operational reliability.

[0034] In some embodiments, the surface of the positioning protrusion 32 may be hardened to enhance wear resistance and ensure a tight fit with the positioning slot 421, preventing slippage during torque transmission. The sliding sleeve rod 33 and the sliding sleeve body 31 may be fixed by welding, and the weld joint shall be inspected for flaws to ensure connection strength.

[0035] According to one embodiment of this application, such as Figure 1 and Figure 3 As shown, a positioning hole 411 is provided on the pump shaft 41, which connects to the first end of the shaft 1 (i.e., Figure 3 The lower end of the connecting shaft 1 is inserted into the positioning hole 411, and the cross-sectional shape of the connecting shaft 1 matches the positioning hole 411 to restrict the relative rotation of the connecting shaft 1 and the pump shaft 41.

[0036] A non-circular positioning hole 411 is machined on the pump shaft 41. The cross-section of the first end of the connecting shaft 1 is adapted to the shape of the positioning hole 411. This structure relies on the geometric characteristics of the non-circular cross-section to restrict the circumferential relative rotation between the connecting shaft 1 and the pump shaft 41. This structure directly forms a circumferential lock between the connecting shaft 1 and the pump shaft 41, providing a stable installation reference for the bushing 2 and the sliding sleeve 3.

[0037] The non-circular cross-section fit stably restricts the circumferential rotation of the connecting shaft 1 and the pump shaft 41, counteracting the reverse torque generated when tightening the nut 42 and maintaining the stability of the connecting shaft 1 reference. When the sliding sleeve 3 rotates smoothly around the connecting shaft 1, it does not generate an axial component force, and the positioning protrusion 32 is less likely to dislodge from the positioning slot 421, reducing damage to the precision parts of the turbine pump 4. Furthermore, the tightening operation can be completed by a single person, improving assembly efficiency while ensuring the assembly accuracy of the rotor system's axial preload.

[0038] The shape of the positioning hole 411 is as follows Figure 1 As shown, the cross-sectional shape of connecting shaft 1 is as follows: Figure 3 As shown, a limiting tooth 12 is provided on the outer circumferential surface of the connecting shaft 1.

[0039] According to one embodiment of this application, a guide portion (not shown in the figure) is formed at the first end of the connecting shaft 1.

[0040] The first end of the connecting shaft 1 is formed with a guide part. This structure is used to guide the connecting shaft 1 to complete the docking with the non-circular positioning hole 411 on the pump shaft 41, reduce the alignment difficulty during insertion, avoid collision between the connecting shaft 1 and the opening of the positioning hole 411, ensure the precise cooperation between the connecting shaft 1 and the pump shaft 41, and provide a stable positioning basis for subsequent assembly and tightening operations of the tooling.

[0041] In some embodiments, the radial dimension of the guide portion is smaller than the opening size of the positioning hole 411, which facilitates quick insertion and alignment.

[0042] According to one embodiment of this application, such as Figure 3 and Figure 4 As shown, the end of the connecting shaft 1 away from the pump shaft 41 is provided with a first rotating hole 11, which is a blind hole; or, the connecting shaft 1 is provided with a second rotating hole (not shown in the figure) that passes through it axially.

[0043] The connecting shaft 1 can be configured with two different types of rotating holes: the first rotating hole 11 is a blind hole, located at the end of the connecting shaft 1 away from the pump shaft 41, and the blind hole structure retains the structural strength of the end of the connecting shaft 1. The second rotating hole is set through the connecting shaft 1 along its own axial direction, which is easy to process.

[0044] The cross-sections of the first rotating hole 11 and the second rotating hole can be regular hexagons.

[0045] For example, the first rotating hole 11 can be a hexagonal countersunk hole.

[0046] The operator can restrict the rotation of the connecting shaft 1 by inserting a hex wrench into the first rotating hole 11 or the second rotating hole, thereby restricting the rotation of the pump shaft 41, so that the pump shaft 41 is fixed during the assembly of the nut 42, and the nut 42 can be reliably installed.

[0047] According to one embodiment of this application, such as Figure 4 As shown, the hollow region of bushing 2 matches the cross-sectional shape of connecting shaft 1 to restrict the relative rotation of bushing 2 and connecting shaft 1.

[0048] The hollow area of ​​bushing 2 is adapted to the cross-sectional shape of connecting shaft 1. The fit of the geometric structure achieves circumferential positioning of the two, preventing relative rotation between bushing 2 and connecting shaft 1. This structure allows bushing 2 to be securely fitted onto connecting shaft 1, ensuring that the rotational support surface formed by the outer circumference of bushing 2 remains coaxial and stable, providing a smooth rotational carrier for sliding sleeve 3. Together with the positioning structure of connecting shaft 1 and pump shaft 41, it ensures the overall assembly accuracy of the tooling.

[0049] According to one embodiment of this application, such as Figure 4As shown, the bushing 2 is fixedly connected to the connecting shaft 1, so that the bushing 2 is fixed in position on the connecting shaft 1.

[0050] The bushing 2 and the connecting shaft 1 are fixedly connected, and there is no relative movement between them. On the basis of restricting the relative rotation of the two in the circumferential direction, the relative movement of the two in the axial direction is further restricted, so that the outer peripheral support surface of the bushing 2 is always in a stable state, providing constant rotational support for the sliding sleeve 3. Together with the positioning structure of the connecting shaft 1 and the pump shaft 41, the reference stability of the tooling is guaranteed.

[0051] After the bushing 2 is fixed, it can maintain the coaxiality and stability of the support surface. When the sliding sleeve 3 rotates, it will not cause support offset, reduce tooling vibration, prevent the positioning protrusion 32 from falling out of the positioning slot 421, and make the torque transmission more uniform when operated by a single person. It is conducive to precise control of the axial preload of the nut 42, and improves the assembly accuracy and reliability of the turbine pump 4.

[0052] In some embodiments, the bushing 2 and the connecting shaft 1 can be fixed by an interference fit, with the relative displacement limited by the tightness of the fit. Of course, the bushing 2 and the connecting shaft 1 can also be fixed by welding or other methods.

[0053] In some embodiments, a wear-resistant coating may be sprayed onto the outer circumferential surface of the bushing 2 to extend the service life of the rotating support surface.

[0054] According to one embodiment of this application, such as Figure 5 As shown, a rotating boss 34 is provided at the free end of the sliding sleeve rod 33. The rotation axis of the rotating boss 34 is parallel to the rotation axis of the sliding sleeve body 31. The rotating boss 34 rotates to drive the sliding sleeve body 31 to rotate.

[0055] The rotating boss 34 is mounted on the sliding sleeve rod 33, and its rotation axis is parallel to the rotation axis of the sliding sleeve body 31. The operator applies torque to the rotating boss 34 using a wrench, which is then transmitted to the sliding sleeve body 31 via the sliding sleeve rod 33, causing the positioning protrusion 32 to rotate synchronously, optimizing the tightening operation experience. The entire force application process is smoother, and the torque transmission is more uniform. The sliding sleeve body 31 rotates more smoothly, reducing tooling vibration, and preventing the positioning protrusion 32 from easily dislodging from the positioning slot 421, protecting the precision parts of the turbine pump 4. This structure is suitable for single-person operation, improving the efficiency and stability of tightening the nut 42 and ensuring the control accuracy of the rotor axial preload.

[0056] According to one embodiment of this application, such as Figure 3 As shown, the rotating boss 34 is a hexagonal boss.

[0057] The rotating boss 34 is formed with a regular hexagonal structure. The multiple sides of the hexagon can provide uniform force points, which can be used for manual force application or with conventional standard tools. The hexagonal boss is stably connected to the sliding sleeve rod 33, which can smoothly transmit the rotational torque when force is applied, driving the sliding sleeve body 31 to rotate. The structure is easy to process and is suitable for the high torque tightening operation requirements of the turbine pump 4 shaft end nut 42.

[0058] According to one embodiment of this application, the sliding sleeve body 31 and the bushing 2 are clearance fit.

[0059] The sliding sleeve body 31 is fitted onto the outside of the bushing 2, with a clearance fit between them to maintain a suitable fit clearance. This fit ensures that the sliding sleeve body 31 can rotate freely and smoothly around the bushing 2, while also limiting the large radial movement of the sliding sleeve body 31. Together with the fixed structure of the bushing 2 and the connecting shaft 1, it provides stable rotational support for the sliding sleeve 3, and meets the torque transmission requirements when the nut 42 is tightened.

[0060] The clearance fit reduces the frictional resistance when the sliding sleeve body 31 rotates, making it easier for the operator to apply force and ensuring smoother rotation of the sliding sleeve 3. The overall vibration amplitude of the tooling is reduced, and the fit between the positioning protrusion 32 and the positioning slot 421 is more stable, reducing the risk of disengagement. When operated by a single person, the torque transmission is uniform and continuous, which can improve tightening efficiency and ensure the assembly accuracy of the axial preload of the turbine pump 4 rotor.

[0061] In some embodiments, both the inner wall of the sleeve body 31 and the outer peripheral surface of the bushing 2 can be smoothed to reduce frictional loss at the mating surfaces. An annular oil reservoir can also be formed on the outer peripheral surface of the bushing 2 to accommodate lubricating media and reduce rotational friction at the mating surfaces.

[0062] According to one embodiment of this application, such as Figure 5 As shown, there are four positioning protrusions 32, which are evenly arranged along the circumference of the sliding sleeve body 31.

[0063] Four positioning protrusions 32 are evenly distributed circumferentially at the end of the sliding sleeve body 31. The evenly distributed protrusions can cooperate with the corresponding positioning slots 421 on the nut 42. This arrangement makes the tightening torque evenly distributed on each protrusion, avoiding localized force concentration. Combined with the smooth rotation of the sliding sleeve 3, it stably transmits torque and is suitable for the high torque tightening conditions of the nut 42 at the shaft end of the turbine pump 4.

[0064] In some embodiments, the height of each positioning protrusion 32 is kept consistent to ensure stable engagement with the positioning slot 421. The positioning protrusion 32 and the sliding sleeve body 31 are integrally formed to ensure the overall structural strength.

[0065] The shaft end nut tightening fixture provided in this application embodiment can be operated by a single person, eliminating the need for dedicated personnel to support the fixture and effectively saving manpower; through the built-in mechanical stabilization structure (connecting shaft 1 as the installation reference), it fundamentally prevents the fixture from slipping and avoids scratching precision parts; the shaft end nut tightening fixture has high stability, a clear torque transmission path, and more precise preload control; it is safe and efficient to operate, has a compact structure, is easy to assemble and disassemble, and is suitable for confined spaces and complex working conditions.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate this application and are not intended to limit this application. Although this application has been described in detail with reference to the embodiments, those skilled in the art should understand that various combinations, modifications, or equivalent substitutions of the technical solutions of this application do not depart from the spirit and scope of the technical solutions of this application and should be covered within the scope of the claims of this application.

Claims

1. A tooling for tightening a shaft end nut, characterized in that, It is applied to a turbo pump (4), on which a pump shaft (41) is provided, and the shaft end nut tightening tool is used to tighten the nut (42) onto the pump shaft (41); The shaft end nut tightening fixture includes: A connecting shaft (1) is used to connect to the pump shaft (41) and serves as an installation reference; A bushing (2) is fitted onto the connecting shaft (1), and the outer circumferential surface of the bushing (2) forms a rotational support surface; Sliding sleeve (3), comprising: The sliding sleeve body (31) is annular and sleeved on the outside of the bushing (2); A positioning protrusion (32) is provided at one end of the sliding sleeve body (31) facing the pump shaft (41) for engaging with the positioning groove (421) on the nut (42); The sliding rod (33) is connected to the outer peripheral surface of the sliding body (31) to drive the sliding body (31) and the positioning protrusion (32) to rotate.

2. The shaft end nut tightening fixture according to claim 1, characterized in that, The pump shaft (41) is provided with a positioning hole (411), the first end of the connecting shaft (1) is inserted into the positioning hole (411), and the cross-sectional shape of the connecting shaft (1) matches the positioning hole (411) to restrict the relative rotation of the connecting shaft (1) and the pump shaft (41).

3. The shaft end nut tightening fixture according to claim 2, characterized in that, A guide portion is formed at the first end of the connecting shaft (1).

4. The shaft end nut tightening fixture according to claim 2, characterized in that, The connecting shaft (1) has a first rotating hole (11) at the end opposite to the pump shaft (41), and the first rotating hole (11) is a blind hole; or The connecting shaft (1) is provided with a second rotating hole that passes through its own axis.

5. The shaft end nut tightening fixture according to claim 2, characterized in that, The hollow region of the bushing (2) matches the cross-sectional shape of the connecting shaft (1) to restrict the relative rotation of the bushing (2) and the connecting shaft (1).

6. The shaft end nut tightening fixture according to claim 5, characterized in that, The bushing (2) is fixedly connected to the connecting shaft (1), so that the bushing (2) is fixed in position on the connecting shaft (1).

7. The shaft end nut tightening fixture according to claim 1, characterized in that, The free end of the sliding sleeve rod (33) is provided with a rotating boss (34), and the rotation axis of the rotating boss (34) is parallel to the rotation axis of the sliding sleeve body (31). The rotating boss (34) rotates to drive the sliding sleeve body (31) to rotate.

8. The shaft end nut tightening fixture according to claim 7, characterized in that, The rotating boss (34) is a hexagonal boss.

9. The shaft end nut tightening fixture according to any one of claims 1 to 8, characterized in that, The sliding sleeve body (31) and the bushing (2) are clearance fit.

10. The shaft end nut tightening fixture according to any one of claims 1 to 8, characterized in that, The positioning protrusions (32) are four in number and are evenly arranged along the circumference of the sliding sleeve body (31).

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