Closed high-pressure multistage centrifugal pump impeller and centrifugal pump

Abstract

The utility model belongs to centrifugal pump technical field especially relates to centrifugal pump impeller, the utility model provides a kind of closed high pressure multistage centrifugal pump impeller and centrifugal pump, comprising: impeller and pump shaft, the impeller is set on the pump shaft by the inner hole of its wheel hub center;Several key grooves are set on the wheel hub of the impeller, corresponding several transmission keys are provided on the pump shaft, the key groove is the trapezoidal through slot extending along axial direction;Two side working surfaces of the key groove are inclined plane, and the included angle α between it and key groove bottom surface is 10 to 15 degrees;The connecting place of side working surface and bottom surface of the key groove, and the corresponding edge of transmission key is all processed with inverted arc angle;The utility model is set along the trapezoidal through slot key groove extending along axial direction and the trapezoidal transmission key matched with it, realizes the power transmission path between impeller and pump shaft between big torque, high reliability, provides basic guarantee for high pressure working condition.

Description

Technical Field

[0001] This utility model belongs to the field of centrifugal pump technology, specifically relating to centrifugal pump impellers, and more particularly to closed-type high-pressure multistage centrifugal pump impellers and centrifugal pumps. Background Technology

[0002] In low-speed heavy industrial fields such as mine drainage, mineral processing, coal hydraulic transportation, and power plant slag discharge, multistage closed-loop centrifugal pumps are core power equipment. These pumps operate under harsh conditions for extended periods, including high pressure, high flow rates, and media containing solid particles (such as slurry and ash), placing extremely stringent demands on their reliability, lifespan, and shock resistance.

[0003] As the core working component of a pump, the impeller's structural design and assembly reliability directly determine the performance and lifespan of the entire pump. Traditional multistage closed centrifugal pump impeller assemblies are usually composed of an impeller body and a drive shaft connected by a key. The impeller body is usually a closed structure with several curved blade channels inside to achieve effective pressurization and transportation of the medium.

[0004] In transmission connections, keyed or splined connections are commonly used. However, machining rectangular keyways on the impeller hub bore and pump shaft, and then using rectangular keyways for circumferential fixation to transmit torque, results in severe stress concentration, making it highly susceptible to fatigue cracks and potentially causing tearing at the keyway of the shaft or impeller hub. Furthermore, keyed connections cannot provide effective axial restraint, with the axial force entirely borne by the pump's balancing mechanism or thrust bearing, increasing system uncertainty. Splines can transmit greater torque, but the high precision required for the splined shaft and splined sleeve necessitates specialized tools and equipment, significantly increasing manufacturing and maintenance costs. Moreover, stress concentration at the tooth root still exists, especially in rectangular splines, where the tooth root remains a fatigue weak point.

[0005] To overcome the drawbacks of keyed connections, a keyless hot-fit interference fit technology is employed. This technology transmits torque through the static friction generated by the large interference between the impeller and the shaft, eliminating stress concentration sources and significantly improving the smoothness and reliability of the connection. However, this technology places extremely strict requirements on the machining accuracy, surface roughness, and assembly process (which requires heating or cooling) of the mating surfaces. Disassembly is extremely difficult, and on-site maintainability is poor, making it unsuitable for field conditions such as mines where frequent maintenance is required or conditions are limited.

[0006] It should be noted that the information disclosed in this background section is only for understanding the background technology of the present application concept, and therefore, the above description is not considered to constitute prior art information. Utility Model Content

[0007] This disclosure provides at least one closed-loop high-pressure multistage centrifugal pump impeller and centrifugal pump to solve the above-mentioned technical problems.

[0008] In a first aspect, embodiments of this disclosure provide a closed-loop high-pressure multistage centrifugal pump impeller and centrifugal pump, comprising: an impeller and a pump shaft, wherein the impeller is fitted onto the pump shaft through an inner hole at the center of its hub; a plurality of keyways are provided on the hub of the impeller, and a plurality of transmission keys are correspondingly provided on the pump shaft, wherein the keyways are trapezoidal through slots extending axially; the two working surfaces of the keyways are inclined surfaces, the angle α between them and the bottom surface of the keyway is 10° to 15°; the connection between the working surfaces of the keyways and the bottom surface, as well as the corresponding edges of the transmission keys, are all machined with rounded corners, the radius of which is 1 / 10 to 1 / 8 of the width of the keyway opening; the depth H of the keyway, starting from the outer surface of the impeller hub, is 1 / 3 to 1 / 2 of the hub thickness T.

[0009] In one optional embodiment, the transmission key is a trapezoidal key adapted to the keyway, which is fixed in the keyway of the pump shaft by interference fit and contacts the working surface of the impeller on the keyway side by clearance fit or transition fit.

[0010] In one alternative embodiment, the included angle α of the keyway is 12°.

[0011] In one alternative embodiment, the radius of the rounded corner is 1 / 9 of the width of the keyway opening.

[0012] In one alternative embodiment, the depth H of the keyway is 2 / 5 of the impeller hub thickness T.

[0013] Secondly, this disclosure also provides a centrifugal pump, including: a pump casing, a bearing component, and at least two stages of impeller assemblies, wherein each stage of the impeller assemblies is sequentially connected in series on the same pump shaft; the impeller hub is provided with a plurality of keyways, and the pump shaft is provided with a plurality of transmission keys, wherein the keyways are trapezoidal through grooves extending axially.

[0014] In one optional embodiment, the transmission key is a trapezoidal key adapted to the keyway, which is fixed in the keyway of the pump shaft by interference fit and contacts the working surface of the impeller on the keyway side by clearance fit or transition fit.

[0015] In one optional embodiment, the connection between the side working surface and the bottom surface of the keyway, as well as the corresponding edge of the transmission key, are all machined with rounded corners, the radius of which is 1 / 10 to 1 / 8 of the width of the keyway opening.

[0016] In one alternative embodiment, the depth H of the keyway, starting from the outer surface of the impeller hub, is 1 / 3 to 1 / 2 of the hub thickness T.

[0017] In one optional embodiment, the two working surfaces of the keyway are inclined surfaces, and the angle α between them and the bottom surface of the keyway is 10° to 15°.

[0018] The beneficial effect of this utility model is that it provides a closed-loop high-pressure multistage centrifugal pump impeller and centrifugal pump: 1. By setting a trapezoidal through-slot keyway extending along the axial direction and a matching trapezoidal transmission key, a high-torque, high-reliability power transmission path between the impeller and the pump shaft is realized, providing a basic guarantee for high-pressure working conditions. 2. By optimizing the angle α between the working surface on the keyway side and the bottom surface to 10° to 15°, the principle of inclined plane mechanics is cleverly utilized to introduce a significant self-locking effect in the key connection. This effectively suppresses the loosening of the transmission key when subjected to alternating axial force and vibration load, improves the long-term dynamic stability of the connection, and reduces the maintenance rate of failures caused by fretting wear. 3. By machining a specific proportion of rounded corners on the corresponding edges of the keyway and drive key, the stress concentration factor at the root of the keyway is greatly reduced, and a uniform and smooth stress distribution is obtained, thereby improving the service life of the impeller hub and drive key under high cycle fatigue load.

[0019] Other features and advantages of this invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objectives and other advantages of this invention are realized and obtained through the structures particularly pointed out in the description and the accompanying drawings.

[0020] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, preferred embodiments are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0021] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 A perspective view of the connection state between the impeller and the pump shaft provided in an embodiment of this disclosure; Figure 2 A perspective view of the impeller provided in an embodiment of this disclosure; Figure 3 This is a structural diagram of an impeller provided in an embodiment of the present disclosure.

[0023] In the picture: 1. Impeller; 11. Keyway; 2. Pump shaft; 21. Transmission key. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0025] In this document, when it is mentioned that a first component is located on a second component, this can mean that the first component can be directly formed on the second component, or that a third component can be inserted between the first and second components. Furthermore, in the accompanying drawings, the thickness of the components may be exaggerated or reduced for the purpose of effectively describing the technical content.

[0026] In this document, exemplary embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. As used herein, expressions such as “at least one of…” modify the entire list of elements when following a list of elements, rather than individual elements in the list. For example, the expression “at least one of a, b, and c” should be understood to include only a, only b, only c, both a and b, both a and c, both b and c, or all of a, b, and c.

[0027] The terminology used herein is for the purpose of describing specific exemplary configurations only and is not intended to be limiting. As used herein, the singular articles “a,” “an,” and “the” may also be intended to include plural forms unless otherwise clearly stated herein. The terms “comprising,” “including,” and “having” are inclusive and thus specify the presence of features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein should not be construed as requiring them to be performed in the specific order discussed or shown, unless specifically identified as such. Additional or alternative steps may be employed.

[0028] As used herein, the phrases “in one embodiment,” “according to one embodiment,” “in some embodiments,” etc., generally refer to the fact that a particular feature, structure, or characteristic following the phrase can be included in at least one embodiment of this disclosure. Therefore, a particular feature, structure, or characteristic can be included in more than one embodiment of this disclosure, such that these phrases do not necessarily refer to the same embodiment. As used herein, the terms “example,” “exemplary,” etc., are used to “serve as an example, instance, or illustration.” Any implementation, aspect, or design described herein as “example” or “exemplary” is not necessarily to be construed as preferred or superior to other implementations, aspects, or designs. Rather, the use of the terms “example,” “exemplary,” etc., is intended to present concepts in a specific manner.

[0029] Research has revealed the following drawbacks of existing technologies: In transmission connections, keyed or splined connections are commonly used. However, machining rectangular keyways on the impeller hub bore and pump shaft, and then using rectangular keys for circumferential fixation to transmit torque, results in severe stress concentration, making fatigue cracks highly likely and leading to tearing at the keyway of the shaft or impeller hub. Furthermore, keyed connections cannot provide effective axial restraint; this axial force is entirely borne by the pump's balancing mechanism or thrust bearing, increasing system uncertainty. Splines can transmit greater torque, but the high precision required for the splined shaft and splined sleeve necessitates specialized tools and equipment, significantly increasing manufacturing and maintenance costs. Moreover, stress concentration at the tooth root still exists, especially in rectangular splines, where the tooth root remains a fatigue weak point.

[0030] To overcome the drawbacks of keyed connections, a keyless hot-fit interference fit technology is employed. This technology transmits torque through the static friction generated by the large interference between the impeller and the shaft, eliminating stress concentration sources and significantly improving the smoothness and reliability of the connection. However, this technology places extremely strict requirements on the machining accuracy, surface roughness, and assembly process (which requires heating or cooling) of the mating surfaces. Disassembly is extremely difficult, and on-site maintainability is poor, making it unsuitable for field conditions such as mines where frequent maintenance is required or conditions are limited.

[0031] The shortcomings of the above solutions are the result of the utility model inventor's practice and careful research. Therefore, the discovery process of the above problems and the solutions proposed in this disclosure should be considered as contributions made by the utility model inventor to this disclosure.

[0032] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0033] The following detailed description, with reference to the accompanying drawings, describes some embodiments of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0034] like Figures 1 to 3 As shown, some embodiments provide a closed-loop high-pressure multistage centrifugal pump impeller and centrifugal pump, including: an impeller 1 and a pump shaft 2. The impeller 1 is fitted onto the pump shaft 2 through the inner hole at the center of its hub. In the closed-loop high-pressure multistage centrifugal pump of this embodiment, the impeller 1 is its core working element. In order to achieve efficient and reliable power transmission, the impeller 1 is fitted onto the pump shaft 2 through the inner hole precisely machined at the center of its hub in a transition fit or a small clearance fit. In principle, this connection method constitutes a basic "shaft-hole" fit pair. Its core lies in ensuring that the rotation axis of the impeller and the rotation axis of the pump shaft are highly coincident through the precise contact and constraint between the inner hole and the outer cylindrical surface of the shaft.

[0035] The structure is simple by using precise contact between the inner hole and the outer cylindrical surface of the shaft. The installation and alignment process is relatively direct. More importantly, it can ensure high coaxiality between impeller 1 and pump shaft 2 from the basic structure. In the multi-stage pump series structure, the cumulative coaxiality error of each impeller is the key factor that causes rotor dynamic imbalance, resulting in severe vibration and noise. This direct fitting method lays a good foundation for subsequent dynamic balance correction and is the fundamental prerequisite for ensuring long-term stable, low-vibration and low-noise operation of the pump set.

[0036] Several keyways 11 are provided on the hub of the impeller 1, and several transmission keys 21 are provided on the pump shaft 2 accordingly. The keyway 11 is a trapezoidal through groove extending along the axial direction. Although the impeller 1 and the pump shaft 2 are initially positioned in the circumferential direction through the inner hole, in order to transmit huge driving torque and prevent relative rotation ("slippage") under high load, a more robust torque transmission mechanism must be established between the two. In this embodiment, a keyway 11 is provided on the hub of the impeller 1 along the axial direction, and a transmission key 21 is installed at the corresponding position on the pump shaft 2. This keyway 11 is specially designed as a trapezoidal through groove extending along the axial direction.

[0037] Specifically, keyed connection is a classic shear-resistant connection method. The transmission key 21 acts as a "shear pin" and is embedded between the shaft and the hub. It transmits torque by bearing shear force through its two working surfaces. Instead of the common rectangle, it adopts a "trapezoidal" cross-section. The trapezoidal slope design gives the key and groove a unique mechanical characteristic in the radial and circumferential directions. First, keyed connection greatly enhances the torque transmission capability of simple "shaft-hole" fit, meeting the high power input requirements of high-pressure multistage pumps. Second, the "through groove" design of the trapezoidal through groove facilitates alignment and inspection during processing and assembly. Most importantly, the trapezoidal structure can achieve "self-locking".

[0038] The two working surfaces 111 of the keyway 11 are inclined planes, and the angle α between them and the bottom surface 112 of the keyway is 10° to 15°; preferably, the angle α of the keyway 11 is 12°. The specific angle range is the result of comprehensive optimization of engineering mechanics and tribology. When the impeller is working, in addition to bearing the main driving torque, it will also be subjected to the pulsating axial force generated by the fluid, the inertial force during start-up and shutdown, and possible vibration loads. This inclination angle α makes the mating surface of the key and the groove no longer perpendicular to the force. When there is a tendency to make the impeller and the shaft undergo relative axial displacement (e.g., axial force), due to the existence of the inclined plane, the axial force will be decomposed into a normal force perpendicular to the inclined plane (increasing the normal pressure of the contact surface) and a component force downward along the inclined plane. The increased normal pressure will directly lead to a significant increase in the maximum static friction force between the contact surfaces, thereby generating a mechanical self-locking tendency, effectively resisting the axial fretting and loosening of the key.

[0039] The appropriate bevel angle fundamentally solves the technical problem that traditional rectangular flat keys are prone to fretting wear and loosening under variable loads and impact loads; it activates the simple trapezoidal cross section into an "anti-loosening structure", which greatly improves the long-term service reliability of the connection pair under harsh working conditions and reduces maintenance requirements.

[0040] The connection between the side working surface 111 and the bottom surface 112 of the keyway 11, as well as the corresponding edge of the transmission key 21, are all machined with rounded corners. The radius of the rounded corners is 1 / 10 to 1 / 8 of the width of the keyway 11 opening. The rounded corner treatment at the connection between the side working surface 111 and the bottom surface 112 of the keyway 11, and the corresponding edge of the transmission key 21, is mandatory in this embodiment. The radius R of the rounded corners is limited to 1 / 10 to 1 / 8 of the width W of the keyway 11 opening, preferably 1 / 9 in this embodiment. In principle, this is a classic design that uses "fracture mechanics" and "fatigue strength theory" to combat stress concentration. At abrupt changes or sharp corners in the cross-section of a part, stress lines will become rapidly denser, resulting in local stresses that are much higher than the nominal average stress. This phenomenon is called "stress concentration". The root of the keyway is such a high-stress danger area.

[0041] Under alternating torque loads, stress concentration points are highly susceptible to becoming initiation sites for fatigue cracks, which then gradually propagate, leading to early fatigue fracture of the hub or key. Introducing a rounded corner with a suitable radius can enable a smooth transition of the cross-section, forcing the stress lines to change gradually, thereby reducing the peak stress below the material's fatigue limit. The ratio of radius to width (1 / 10-1 / 8) is the golden ratio verified by finite element analysis and fatigue tests. If it is too small (such as a sharp corner), the improvement effect will be insufficient, while if it is too large, it may excessively weaken the effective load-bearing cross-section.

[0042] The rounded corner treatment significantly improves the fatigue strength of the key connection area and the overall structural life. The trapezoidal cross section itself has a smoother stress flow line than the rectangular cross section. Combined with the large rounded corner transition, it jointly constructs a "low stress valley", which greatly reduces the stress concentration factor. At the same time, the rounded corner also avoids the generation of microcracks at sharp corners during heat treatment or use, thus improving the process robustness.

[0043] The depth H of the keyway 11, starting from the outer surface of the impeller 1 hub, is 1 / 3 to 1 / 2 of its hub thickness T; the depth H of the keyway 11 is 2 / 5 of the impeller 1 hub thickness T. The design of the depth H of the keyway 11, starting from the outer surface of the impeller 1 hub, is limited to 1 / 3 to 1 / 2 of its hub thickness T, and is preferably 2 / 5 in the embodiment. In principle, this is a balanced design that seeks the optimal solution between "transmission strength" and "structural strength". The depth H directly determines the effective embedding depth (i.e., "key height") of the transmission key 21, thereby determining the shear resistance area that the key side can provide, which is related to the torque transmission capability.

[0044] The larger the depth H, the stronger the torque transmission capacity. However, the keyway is like a "wound" on the impeller hub that bears huge centrifugal force and internal pressure. It will weaken the cross-sectional area of ​​the hub and reduce its overall stiffness and strength. The larger the depth H, the more serious this weakening effect. Limiting H / T to the range of 1 / 3 to 1 / 2 (preferably 2 / 5) is the result of strength calibration and optimized design.

[0045] Limiting H / T to the range of 1 / 3 to 1 / 2 (preferably 2 / 5) ensures that the shear strength of the key and the bending / tensile strength of the hub have sufficient safety margins when transmitting rated torque and a certain overload torque. This avoids key shear failure due to excessively shallow keyways or hub breakage due to insufficient strength caused by excessively deep keyways. The above depth ratio is a comprehensive result after considering the improvement of local stress by features such as trapezoidal cross-section, inclined plane angle, and rounded chamfer, making the final design both compact and robust.

[0046] The transmission key 21 is a trapezoidal key that is adapted to the keyway 11. It is fixed in the keyway of the pump shaft 2 by interference fit and contacts the working surface 111 of the keyway 11 side of the impeller 1 by clearance fit or transition fit.

[0047] To achieve the above design intent, the transmission key 21 itself is designed as a trapezoidal key that matches the keyway 11. Its assembly and mating method is carefully arranged: the transmission key 21 is fixed in the keyway of the pump shaft 2 by an interference fit, while it contacts the working surface 111 of the keyway 11 side of the impeller 1 by a clearance fit or a transition fit. In principle, this adopts a differentiated mating strategy of "one side fixed and one side floating". The interference fit on the pump shaft keyway side ensures that the key and the shaft become one, fundamentally eliminating the possibility of micro-movement, rotation or axial movement of the key on the shaft, and ensuring the absolute rigidity of the power input end. The clearance or transition fit on the impeller keyway side provides the necessary "assembly tolerance" and "working tolerance", which facilitates the smooth sliding of the impeller into place during assembly.

[0048] During operation, the impeller is allowed to produce a very small amount of radial or angular wobble due to thermal expansion or deformation under stress, without creating excessive assembly stress or jamming in the keyway; achieving a balance between rigidity and flexibility in the connection: the power input end (shaft-key) is sufficiently rigid to ensure transmission accuracy; the power output end (key-impeller) has appropriate elasticity to adapt to deformation under actual working conditions, improving the overall compatibility and reliability of the system; the above-mentioned fit method realizes the trapezoidal inclined surface self-locking design, the self-locking effect requires good contact between the key and the side of the impeller groove, and the appropriate fit ensures the uniformity of contact; it also benefits from the rounded chamfer, making the assembly process smoother and avoiding scratches.

[0049] Some embodiments provide a centrifugal pump: a pump casing, bearing components, and at least two stages of impeller assemblies, with each stage of impeller assemblies connected in series on the same pump shaft 2; the impeller 1 has a plurality of keyways 11 on its hub, and the pump shaft 2 has a plurality of corresponding drive keys 21, the keyways 11 being trapezoidal through slots extending axially.

[0050] The transmission key 21 is a trapezoidal key that is adapted to the keyway 11. It is fixed in the keyway of the pump shaft 2 by interference fit and contacts the working surface 111 of the keyway 11 side of the impeller 1 by clearance fit or transition fit.

[0051] The connection between the side working surface 111 and the bottom surface 112 of the keyway 11, as well as the corresponding edge of the transmission key 21, are all machined with rounded corners. The radius of the rounded corners is 1 / 10 to 1 / 8 of the width of the opening of the keyway 11.

[0052] The depth H of the keyway 11, starting from the outer surface of the impeller 1 hub, is 1 / 3 to 1 / 2 of its hub thickness T.

[0053] The two working surfaces 111 of the keyway 11 are inclined surfaces, and the angle α between them and the bottom surface 112 of the keyway is 10° to 15°.

[0054] Overall workflow: After the closed-loop high-pressure multistage centrifugal pump is started and running, the motor drives the pump shaft 2 to rotate at high speed. The power transmission path is as follows: the torque of the pump shaft 2 is firmly transmitted to the transmission key 21 through an interference fit; the side of the transmission key 21, with its trapezoidal inclined surface in contact with the inclined surface of the impeller 1 keyway 11, mainly converts the torque into pressure and transmits it to the impeller; at the same time, the fluid reaction torque received by the impeller is also fed back to the key through this inclined surface. In this process, the huge axial thrust borne by the impeller will be converted into a component force that enhances the normal pressure of the keyway contact surface due to the existence of the inclined surface, triggering the friction self-locking effect, firmly locking the transmission key, and preventing its axial movement. Impeller 1 rotates under torque drive, doing work on the liquid inside the pump. At this time, the impeller itself is subjected to huge centrifugal stress, fluid pressure and alternating load. All these loads eventually converge in the keyway area of ​​the hub. Due to the optimized trapezoidal cross section and precisely defined rounded chamfer, the stress is smoothly redistributed at the root of the keyway, avoiding the generation of catastrophic peak stress at the sharp corner, which greatly delays the initiation of fatigue cracks. The designed keyway depth ensures that while providing a sufficient torsional cross section, the hub body still maintains sufficient structural integrity to resist various composite stresses. The entire power transmission chain—from the shaft to the key, and then to the impeller—forms an organic whole with rigid connection, flexible adaptation, stress optimization, and self-locking anti-loosening. Each design feature is interconnected: the trapezoidal cross-section is the basic carrier, the specific slope angle gives it a self-locking function, the rounded chamfer is responsible for eliminating its stress weaknesses, the reasonable depth balances the contradiction between torsion transmission and base reinforcement, and the differentiated matching strategy ensures that this ingenious design can be accurately assembled and adapted to actual working conditions.

[0055] In summary, the above embodiments: By setting a trapezoidal through-slot keyway 11 extending along the axial direction and a matching trapezoidal transmission key 21, a high-torque and high-reliability power transmission path between the impeller 1 and the pump shaft 2 is realized, providing a basic guarantee for high-pressure working conditions. By optimizing the angle α between the working surface 111 on the keyway side and the bottom surface 112 to 10° to 15°, the principle of inclined plane mechanics is cleverly utilized to introduce a significant self-locking effect in the key connection. This effectively suppresses the loosening of the transmission key when subjected to alternating axial force and vibration load, improves the long-term dynamic stability of the connection, and reduces the maintenance rate of failures caused by fretting wear. By machining a specific proportion of rounded corners on the corresponding edges of the keyway 11 and the drive key 21, the stress concentration factor at the root of the keyway is greatly reduced, and a uniform and smooth stress distribution is obtained, thereby improving the life of the impeller hub and the drive key under high cycle fatigue load. By setting the keyway depth H to 1 / 3 to 1 / 2 of the hub thickness T, the optimal balance between the shear bearing capacity of the transmission key and the overall structural strength of the impeller hub is achieved. While ensuring the transmission of rated torque and safety, the hub is not excessively weakened, and the structural safety of the impeller under extreme pressure is improved. By adopting a differentiated assembly strategy of interference fit between transmission key 21 and pump shaft and clearance / transition fit between transmission key 21 and impeller keyway, excellent results were achieved with strong rigidity at the power input end and good adaptability at the output end, which improved the assembly processability and the system's tolerance to different working conditions (such as thermal deformation).

[0056] In the description of the embodiments of this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0057] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing this utility model 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 this utility model. Furthermore, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence unless expressly indicated herein. Therefore, without departing from the teachings of the exemplary embodiments, the first element, component, region, layer, or segment discussed above may be referred to as the second element, component, region, layer, or segment.

[0058] Based on the above-described preferred embodiments of this utility model, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the technical concept of this utility model. The technical scope of this utility model is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A closed-loop high-pressure multistage centrifugal pump impeller, characterized in that, include: Impeller (1) and pump shaft (2), wherein the impeller (1) is fitted onto the pump shaft (2) through the inner hole at the center of its hub; The impeller (1) has several keyways (11) on its hub, and the pump shaft (2) has several transmission keys (21) on its corresponding side. The keyways (11) are trapezoidal through slots extending along the axial direction. The two working surfaces (111) of the keyway (11) are inclined surfaces, and the angle α between them and the bottom surface (112) of the keyway is 10° to 15°. The connection between the side working surface (111) and the bottom surface (112) of the keyway (11), as well as the corresponding edge of the transmission key (21), are all machined with rounded corners. The radius of the rounded corners is 1 / 10 to 1 / 8 of the width of the opening of the keyway (11). The depth H of the keyway (11) extends from the outer surface of the impeller (1) hub to 1 / 3 to 1 / 2 of its hub thickness T.

2. The closed-loop high-pressure multistage centrifugal pump impeller as described in claim 1, characterized in that, The transmission key (21) is a trapezoidal key that is adapted to the keyway (11). It is fixed in the keyway of the pump shaft (2) by interference fit and contacts the working surface (111) of the keyway (11) side of the impeller (1) by clearance fit or transition fit.

3. The closed-loop high-pressure multistage centrifugal pump impeller as described in claim 1, characterized in that, The included angle α of the keyway (11) is 12°.

4. The closed-loop high-pressure multistage centrifugal pump impeller as described in claim 1, characterized in that, The radius of the rounded corner is 1 / 9 of the width of the keyway opening.

5. The closed-loop high-pressure multistage centrifugal pump impeller as described in claim 1, characterized in that, The depth H of the keyway (11) is 2 / 5 of the hub thickness T of the impeller (1).

6. A centrifugal pump, characterized in that, include: The pump casing, bearing components, and at least two stages of impeller assemblies are installed in series on the same pump shaft (2); The impeller (1) has several keyways (11) on its hub, and the pump shaft (2) has several transmission keys (21) on its corresponding side. The keyways (11) are trapezoidal through slots extending axially.

7. The centrifugal pump as described in claim 6, characterized in that, The transmission key (21) is a trapezoidal key that is adapted to the keyway (11). It is fixed in the keyway of the pump shaft (2) by interference fit and contacts the working surface (111) of the keyway (11) side of the impeller (1) by clearance fit or transition fit.

8. The centrifugal pump as claimed in claim 7, characterized in that, The connection between the side working surface (111) and the bottom surface (112) of the keyway (11) and the corresponding edge of the transmission key (21) are all machined with rounded corners, the radius of which is 1 / 10 to 1 / 8 of the width of the opening of the keyway (11).

9. The centrifugal pump as claimed in claim 8, characterized in that, The depth H of the keyway (11) extends from the outer surface of the impeller (1) hub to 1 / 3 to 1 / 2 of its hub thickness T.

10. The centrifugal pump as claimed in claim 9, characterized in that, The two working surfaces (111) of the keyway (11) are inclined surfaces, and the angle α between them and the bottom surface (112) of the keyway is 10° to 15°.

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