Impeller and manufacturing process thereof

Abstract

The application relates to an impeller, belonging to the technical field of impeller production, which comprises a front disc and a rear disc, a plurality of grooves are formed on the side of the front disc facing the rear disc, a plurality of blades are arranged on the side of the rear disc facing the front disc, the blades correspond to the grooves one by one, the side of the blade far from the rear disc is inserted into the corresponding groove, the front disc is made of a material with light transmission, the blade is made of a material with strong laser energy absorption, the materials of the front disc, the rear disc and the blade are all plastic, and the surface of the blade in contact with the groove is laser welded on the front disc. The application has the effects of improving the production efficiency of the impeller, improving the coaxiality and connecting strength of the front disc and the rear disc, and improving the production quality of the impeller.

Description

Technical Field

[0001] This application relates to the field of impeller manufacturing technology, and in particular to an impeller and its manufacturing process. Background Technology

[0002] Given the technical difficulties in manufacturing a complete injection-molded impeller, the impeller is split into a front disc and a rear disc, each molded separately. This simplifies the mold-making process; later, the front and rear discs are joined together using laser welding to form a single impeller. Traditionally, this joining technique has involved ultrasonic welding or adhesive bonding. Ultrasonic welding produces harsh noise, which can damage the operator's hearing over time. Furthermore, ultrasonic welding relies on high-frequency vibration and friction between the two plastic parts to generate heat, and this vibration frequency makes the plastic parts prone to cracking during welding, affecting quality and hindering mass production. Adhesive bonding is also less than ideal. First, adhesive is a consumable, increasing costs. Second, adhesive adds weight to the product. Third, adhesive requires curing time, severely impacting production efficiency. Furthermore, during the docking process of the existing front and rear discs, it is necessary to ensure the coaxiality of the front and rear discs. This requires the production equipment to have precise positioning and fixing devices. Otherwise, during the ultrasonic welding process, the high-frequency vibration of the front and rear discs will cause inaccurate coaxiality, affecting product quality. Summary of the Invention

[0003] In order to improve the production efficiency of the impeller, enhance the coaxiality and connection strength of the front and rear discs, and improve the production quality of the impeller, this application provides an impeller and its manufacturing process.

[0004] The impeller provided in this application adopts the following technical solution:

[0005] An impeller includes a front disc and a rear disc. The front disc has a plurality of grooves on its side facing the rear disc. The rear disc has a plurality of blades on its side facing the front disc. Each blade corresponds to one of the grooves. The side of the blade away from the rear disc is inserted into the corresponding groove. The front disc is made of a light-transmitting material. The blades are made of a material that strongly absorbs laser energy. The front disc, rear disc, and blades are all made of plastic. The surfaces of the blades that contact the grooves are laser-welded to the front disc.

[0006] By adopting the above technical solution, the blades are inserted into the corresponding grooves, which can ensure the coaxiality of the front and rear discs. There is no need to install precise positioning and fixing devices on the production equipment, which reduces the requirements for production equipment and makes processing convenient.

[0007] The groove provides a recessed surface, which effectively increases the welding area, thereby improving the strength and stability of the weld. This design also avoids the stress concentration problem that occurs when the blade is welded only to the surface facing the front disk, reducing stress concentration at the weld point and ensuring the uniformity and strength of the weld.

[0008] Furthermore, the welding is concentrated within the groove, preventing excessive dispersion of laser energy. This facilitates the concentrated melting of specific areas, thereby reducing overall thermal deformation of the impeller and ensuring the precision and quality of the structure.

[0009] Laser welding is characterized by its precision and focus. Because the contact area between the blade and the groove is relatively small, laser welding can complete high-intensity welding within a very localized area. This reduces the overall heating time of the impeller and avoids material deformation or damage caused by overheating.

[0010] The blades are tightly integrated with the front disc via grooves, maintaining structural consistency after welding. This reduces airflow disturbance during impeller rotation and improves aerodynamic performance. Consequently, the impeller can more effectively drive airflow, enhancing overall operating efficiency.

[0011] Meanwhile, using laser welding can improve the connection strength between the impeller and the front disc, and the tensile strength can be greater than 200N.

[0012] In summary, the blade and groove welding surface design offers the dual advantages of precise positioning and enhanced strength. It not only improves the impeller's manufacturing precision but also effectively reduces potential thermal deformation and stress concentration during welding. The groove design ensures blade welding stability and, during laser welding, concentrates laser energy at specific locations, forming a strong weld and improving the overall durability and performance of the impeller. Furthermore, this combination of blade and groove design optimizes the structure's mechanical properties and adapts to the specific requirements of laser welding, making the manufacturing process more efficient and stable.

[0013] Optionally, the front disc is made of polycarbonate / polypropylene / polymethyl methacrylate.

[0014] By adopting the above technical solutions, these materials are usually transparent or semi-transparent, allowing the laser to pass through them to complete the welding. Moreover, these materials have good strength and toughness, and can withstand certain mechanical stress and environmental changes. They also have heat resistance, remaining stable within a certain temperature range and adapting to the temperature rise generated when the impeller is working.

[0015] Optionally, the rear disc is made of glass fiber reinforced nylon / polyamide / polyphenylene sulfide.

[0016] By employing the above-mentioned technical solutions, these materials, due to their dark color, can effectively absorb laser energy, thus promoting the laser welding effect. Furthermore, these materials possess excellent strength, heat resistance, and chemical resistance, making them suitable for long-term operation in high-stress and high-temperature environments. Simultaneously, these engineering plastic materials are reasonably priced, making them suitable for mass production applications.

[0017] Optionally, the side of the front disc facing the rear disc gradually recesses inward toward the central axis of both, the depth of each part of the groove remains the same, and the height of the blade at the end closer to the central axis of the rear disc is greater than the height of the blade at the end farther away from the central axis of the rear disc.

[0018] By adopting the above technical solution, the concave design of the front and rear discs helps optimize airflow guidance. When the impeller rotates, the concave disc surfaces effectively guide the airflow in a specific direction, reducing turbulence and eddies on the disc surfaces. This design reduces aerodynamic drag and improves impeller efficiency.

[0019] The recessed design helps improve the overall strength of the impeller. The recesses in the front and rear discs not only make the disc surface more structural but also better distribute stress during rotation, reducing impeller deformation or torsion. Especially at high speeds, the recessed disc design effectively counteracts the effects of centrifugal force and other external forces, extending the impeller's service life.

[0020] Compared to planar designs, recessed disc designs can improve structural rigidity without increasing thickness or adding extra material, and can even reduce material usage and overall impeller weight while maintaining structural strength. This plays a crucial role in energy saving and efficient operation of the equipment.

[0021] The recessed design of the front and rear discs balances the forces acting on the impeller during rotation. Due to the slight shape difference between the disc surfaces, the recessed design reduces unbalanced aerodynamic loads during rotation, further reducing impeller vibration and improving dynamic balance. This ensures smoother and more efficient equipment operation and reduces mechanical wear.

[0022] The recessed design of the front and rear discs increases the surface area of ​​the discs, which is beneficial for heat dissipation of the impeller when operating at high temperatures or high loads. By increasing the surface area, the recessed parts can help dissipate heat, improving the durability and performance stability of the equipment in high-temperature operating environments.

[0023] Taller blades bear greater bending forces near the central axis. By increasing the height, stress can be dispersed, reducing mechanical fatigue caused by rotation, thereby extending the service life of the blades.

[0024] Lowering the end furthest from the central axis means less material is used, thus reducing the overall weight of the impeller. This design not only reduces material costs but also improves system response speed and energy efficiency, especially in high-speed rotation applications.

[0025] Optionally, the side of the blade facing the front disc is an arc surface and fits against the inner bottom wall of the groove.

[0026] Optionally, a gap is left between the end of the blade away from the central axis of the rear disk and the outer peripheral surface of the disk.

[0027] By employing the above technical solutions, this design helps to distribute airflow evenly. When fluid passes over the blades, the airflow near the outer edge of the disk naturally diffuses, avoiding fluid blockage or impeded flow caused by direct contact between the blades and the outer circumference. The spacing reduces the impact of boundary layer effects on fluid motion and minimizes energy loss due to wall adhesion.

[0028] In some impeller designs, if the blades are completely sealed to the outer circumference, turbulence and pressure buildup may occur at the edges, affecting the impeller's efficiency and stability. Spacing design allows airflow to naturally expand from the blade tips, preventing turbulence from accumulating on the outer wall of the impeller and reducing vibration and noise.

[0029] When the impeller rotates at high speed, the rigid connection between the blades and the outer peripheral surface can cause significant stress concentration, leading to wear or fatigue of the blades or outer peripheral surface. Maintaining proper spacing can reduce stress concentration in the structure and extend the service life of the blades and disk.

[0030] Optionally, the blades are equidistantly distributed around the central axis of the rear disc, and the sides of the blades are configured as outer arc surfaces and inner arc surfaces, with the extended arc of the outer arc surface of the blades gradually converging towards the center of the rear disc.

[0031] By employing the above technical solution, the blades are designed around the central axis, allowing the fluid to be uniformly guided in the direction of rotation, which helps convert kinetic energy into efficient axial or centrifugal flow. By guiding the fluid along the central axis, the blades can accelerate the fluid flow. This axial flow design reduces the generation of lateral airflow, thereby improving the overall flow efficiency of the impeller.

[0032] Optionally, the curvature of the inner arc surface of the blade is smaller than the curvature of the outer arc surface of the blade.

[0033] By employing the above technical solution, the difference in curvature helps control the fluid velocity. The side with a larger curvature accelerates the fluid, while the side with a smaller curvature prevents excessive pressure gradients as the fluid flows. This shape makes the fluid flow within the impeller smoother, reducing unstable airflow phenomena. Furthermore, the fluid can flow smoothly from one end of the impeller to the other, minimizing energy loss. This uneven curvature design typically allows the impeller to maintain high fluid kinetic energy transfer efficiency at high speeds. Simultaneously, the asymmetrical blade design reduces turbulence as the fluid flows over the blade surface, reducing noise generation and improving impeller stability.

[0034] Optionally, the vent of the front disc is provided with a first annular protrusion, and the vent of the rear disc is provided with a second annular protrusion. The diameter of the protruding end of the first annular protrusion is smaller than the diameter of the recessed end of the first annular protrusion, and the diameter of the protruding end of the second annular protrusion is the same as the diameter of the recessed end of the second annular protrusion.

[0035] By adopting the above technical solution, the shape of the first annular protrusion resembles a nozzle, which helps to accelerate the airflow. When gas passes through a narrow area, the airflow velocity increases, thereby generating higher dynamic pressure during the impeller's intake and exhaust processes. This design effectively increases the airflow velocity, making the impeller's intake or exhaust efficiency higher, thus improving the overall performance of the equipment. The second annular protrusion facilitates the connection between the rear disc and components.

[0036] This application also provides a technical solution for impeller manufacturing process using the following method:

[0037] An impeller manufacturing process for manufacturing the aforementioned impeller includes the following steps:

[0038] The front and rear plates were molded separately, and the front and rear plates were cast separately.

[0039] Insert the blade into the corresponding groove;

[0040] Press the front and rear discs together;

[0041] A laser of a fixed wavelength is selected and applied to the surface where the blade contacts the groove, thus welding the blade to the front disc.

[0042] In summary, this application includes at least one of the following beneficial technical effects:

[0043] 1. Laser welding can be used to complete high-strength welding in a very localized area. This reduces the heating time of the entire impeller, avoids material deformation or damage caused by overheating, and improves the connection strength between the impeller and the front disc. The tensile strength can be greater than 200N.

[0044] 2. The blade and groove welding surface design offers the dual advantages of precise positioning and enhanced strength. It not only improves the impeller's manufacturing precision but also effectively reduces potential thermal deformation and stress concentration during welding. The groove design ensures stability during blade welding and, during laser welding, concentrates laser energy at specific locations to form a strong weld, improving the overall durability and performance of the impeller. Furthermore, this combination of blade and groove design optimizes the structure's mechanical properties and adapts to the specific requirements of laser welding, making the manufacturing process more efficient and stable. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the overall structure of an embodiment of this application.

[0046] Figure 2 This is a schematic diagram illustrating the structure of the first outer surface and the first annular protrusion in an embodiment of this application.

[0047] Figure 3 This is a schematic diagram illustrating the structure of the second inner surface, the second annular protrusion, and the impeller in an embodiment of this application.

[0048] Explanation of reference numerals in the attached drawings: 1. Front disc; 11. First inner surface; 12. First outer surface; 13. First annular protrusion; 14. Groove; 2. Rear disc; 21. Second inner surface; 22. Second outer surface; 23. Second annular protrusion; 3. Blade. Detailed Implementation

[0049] The following is in conjunction with the appendix Figure 1-3 This application will be described in further detail.

[0050] This application discloses an impeller.

[0051] like Figure 1 , Figure 2 and Figure 3 The impeller includes a front disc 1 and a rear disc 2;

[0052] The side of the front disc 1 facing the rear disc 2 is defined as the first inner surface 11, the side of the front disc 1 away from the rear disc 2 is defined as the first outer surface 12, the side of the rear disc 2 facing the front disc 1 is defined as the second inner surface 21, and the side of the rear disc 2 away from the front disc 1 is defined as the second outer surface 22.

[0053] The first inner surface 11 is an annular arc surface that is concave towards the central axis and away from the rear disc 2, and the first outer surface 12 is an annular arc surface that is convex towards the central axis and away from the rear disc 2. The slope of the first outer surface 12 and the first inner surface 11 gradually decreases towards the central axis, that is, the curvature of the first outer surface 12 and the first inner surface 11 gradually becomes gentler towards the central axis.

[0054] The front disc 1 is integrally formed with a first circular protrusion 13. The front disc 1 is coaxially arranged with the first circular protrusion 13. The outer peripheral surface of the first circular protrusion 13 is connected to the first outer surface 12, and the inner peripheral surface of the first circular protrusion 13 is connected to the first inner surface 11. The arc-shaped surface of the outer peripheral surface of the first circular protrusion 13 and the slope of the outer peripheral surface and the inner peripheral surface of the first circular protrusion 13 gradually increase in the direction away from the rear disc 2, thereby forming that the diameter of the protruding end of the first circular protrusion 13 is smaller than the diameter of the recessed end of the first circular protrusion 13.

[0055] The inner surfaces of the first inner surface 11 and the first annular protrusion 13 are provided with a plurality of grooves 14. The depth of the grooves 14 is 3mm. The depth of each part of the grooves 14 is the same. The plurality of grooves 14 are arranged equidistantly along the circumference of the front disc 1. The inner sidewalls on both sides of the grooves 14 are arc-shaped sides. The two inner sidewalls of the grooves 14 have the same curvature direction. The curvature of the inner sidewall of one groove 14 is smaller than the curvature of the other inner sidewall of the groove 14.

[0056] The width of the end of the groove 14 near the outer peripheral surface of the front disc 1 is less than the width of the end of the groove 14 away from the outer peripheral surface of the front disc 1. There is a gap between the end of the groove 14 near the outer peripheral surface of the front disc 1 and the outer peripheral surface of the front disc 1. The extended arc of the large arc side of the groove 14 gradually converges towards the center of the front disc 1.

[0057] The second inner surface 21 is an annular arc surface that protrudes towards the central axis and towards the front disc 1, and the second outer surface 22 is an annular arc surface that is recessed towards the central axis and towards the front disc 1. The slope of the second outer surface 22 and the second inner surface 21 gradually decreases towards the central axis, that is, the curvature of the second outer surface 22 and the second inner surface 21 gradually becomes gentler towards the central axis.

[0058] The rear disc 2 is integrally formed with a second annular protrusion 23. The second annular protrusion 23 is coaxially arranged with the rear disc 2. The outer peripheral surface of the second annular protrusion 23 is connected to the second inner surface 21, and the inner peripheral surface of the second annular protrusion 23 is connected to the second outer surface 22. The arc-shaped surface of the outer peripheral surface of the second annular protrusion 23 and the slope of the outer peripheral surface of the second annular protrusion 23 and the slope of the inner peripheral surface of the second annular protrusion 23 both gradually decrease towards the central axis of the rear disc 2. The diameter of the protruding end of the second annular protrusion 23 is equal to the diameter of the recessed end of the second annular protrusion 23.

[0059] The second outer surface 22 is integrally formed with several blades 3, each blade 3 corresponding to and fitting into a groove 14.

[0060] The height of the end of blade 3 near the central axis of rear plate 2 is greater than the height of the end of blade 3 away from the central axis of rear plate 2. The side of blade 3 facing front plate 1 is an arc surface and fits against the inner bottom wall of groove 14. There is a gap between the end of blade 3 away from the central axis of rear plate 2 and the outer peripheral surface of rear plate 2. Blades 3 are equidistantly distributed around the central axis of rear plate 2, and the side of blade 3 is set as an outer arc surface and an inner arc surface. The extended arc of the outer arc surface of blade 3 gradually converges towards the center of rear plate 2. The curvature of the inner arc surface of blade 3 is smaller than the curvature of the outer arc surface of blade 3.

[0061] The front disc 1, rear disc 2 and blade 3 are made of plastic. The rear disc 2 and blade 3 are made of the same material. The front disc 1 can be made of polycarbonate / polypropylene / polymethyl methacrylate. The rear disc 2 and blade 3 can be made of glass fiber reinforced nylon / polyamide / polyphenylene sulfide.

[0062] Since the materials used in the front disc 1 are usually transparent or semi-transparent, the laser can pass through these materials to complete the welding. Moreover, these materials have good strength and toughness, and can withstand certain mechanical stress and environmental changes. At the same time, these materials also have heat resistance, remain stable within a certain temperature range, and adapt to the temperature rise generated when the impeller is working.

[0063] The material used in the second plate, due to its darker color, effectively absorbs laser energy, promoting better laser welding. Furthermore, these materials possess excellent strength, heat resistance, and chemical resistance, making them suitable for long-term operation in high-stress and high-temperature environments. At the same time, these engineering plastic materials are reasonably priced, making them suitable for mass production applications.

[0064] Therefore, the surface of blade 3 that contacts groove 14 can be laser welded to front disc 1.

[0065] When connecting the front disc 1 and the rear disc 2, inserting the blade 3 into the corresponding groove 14 can ensure the coaxiality of the front disc 1 and the rear disc 2. It does not require the installation of precise positioning and fixing devices on the production equipment, thus reducing the requirements for production equipment and making it convenient for processing.

[0066] The groove 14 provides a recessed surface, which can effectively increase the welding area, thereby improving the strength and stability of the weld. This design also avoids the stress concentration problem that occurs when the blade 3 is welded only on the surface facing the front disk 1, reducing stress concentration at the weld point and ensuring the uniformity and strength of the weld point.

[0067] Furthermore, the welding is concentrated within the groove 14, so the laser energy is not excessively dispersed, which is conducive to the concentrated melting of specific areas, thereby reducing the overall thermal deformation of the impeller and ensuring the precision and quality of the structure.

[0068] Laser welding is characterized by its precision and focus. Because the contact area between blade 3 and groove 14 is relatively small, laser welding can complete high-intensity welding in a very localized area. This reduces the overall heating time of the impeller and avoids material deformation or damage caused by overheating.

[0069] The blade 3 is tightly integrated with the front disc 1 via the groove 14, maintaining structural integrity after welding. This reduces airflow disturbance during impeller rotation and improves aerodynamic performance. Consequently, the impeller can more effectively drive airflow, enhancing overall working efficiency.

[0070] Meanwhile, laser welding can improve the connection strength between the impeller and the front disc 1, and the tensile strength can be greater than 200N.

[0071] The recessed design of the front disc 1 and rear disc 2 helps optimize airflow guidance. As the impeller rotates, the recessed disc surfaces effectively guide airflow in a specific direction, reducing turbulence and eddies on the disc surfaces. This design reduces aerodynamic drag and improves impeller efficiency.

[0072] The recessed design helps improve the overall strength of the impeller. The recesses in the front disc 1 and rear disc 2 not only make the disc surface more structural, but also better distribute stress during rotation, reducing impeller deformation or torsion. Especially at high speeds, the recessed disc design can effectively counteract the effects of centrifugal force and other external forces, extending the impeller's service life.

[0073] The design of leaving a gap between the end of blade 3 furthest from the central axis of rear disk 2 and the outer circumference of the disk helps to distribute airflow evenly. When fluid passes through blade 3, the airflow near the outer side of blade 3 will naturally diffuse, avoiding fluid blockage or poor flow caused by direct contact between blade 3 and the outer circumference. Leaving a gap can reduce the influence of boundary layer effect on fluid motion and reduce energy loss caused by wall adhesion effect.

[0074] The blades 3 are designed around the central axis, allowing the fluid to be uniformly guided in the direction of rotation, which helps convert kinetic energy into efficient axial or centrifugal flow. By guiding the fluid along the central axis, the blades 3 can accelerate the fluid flow. This axial flow design reduces the generation of lateral airflow, thereby improving the overall flow efficiency of the impeller.

[0075] The first annular protrusion 13, shaped like a nozzle, accelerates the airflow. As gas passes through a narrow area, its velocity increases, creating higher dynamic pressure during impeller intake and exhaust. This design effectively increases airflow velocity, improving impeller intake and exhaust efficiency, and ultimately enhancing the overall performance of the equipment.

[0076] The implementation principle of this application embodiment is as follows: the front disc 1 is made of a material with good light transmittance, while the rear disc 2 and blades 3 are made of materials with strong laser energy absorption. The impeller is manufactured using a laser welding process, utilizing the cooperation between the blades 3 and the grooves 14. The welding surface design of the blades 3 and grooves 14 provides the dual advantages of precise positioning and enhanced strength. It not only improves the manufacturing precision of the impeller but also effectively reduces thermal deformation and stress concentration that may occur during welding. The groove design 14 ensures the stability of the blades 3 during welding and, during laser welding, can concentrate laser energy at specific locations to form a strong weld, improving the overall durability and performance of the impeller. Simultaneously, this combination of blade 3 and groove design not only optimizes the mechanical properties of the structure but also adapts to the special requirements of the laser welding process, making the manufacturing process more efficient and stable.

[0077] This application also provides an impeller manufacturing process for producing the impellers of this application embodiment, including the following steps:

[0078] The front plate 1 and the rear plate 2 are molded separately, and the front plate 1 and the rear plate 2 are cast separately.

[0079] Insert blade 3 into the corresponding groove 14;

[0080] Press the front plate 1 and the rear plate 2 together;

[0081] A laser of a fixed wavelength is selected and applied to the surface where the blade 3 contacts the groove 14, thereby welding the blade 3 to the front disc 1.

[0082] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. An impeller, characterized in that: The device includes a front plate (1) and a rear plate (2). The front plate (1) has several grooves (14) on the side facing the rear plate (2). The rear plate (2) has several blades (3) on the side facing the front plate (1). Each blade (3) corresponds to one of the grooves (14). The side of the blade (3) away from the rear plate (2) is inserted into the corresponding groove (14). The front plate (1) is made of a light-transmitting material. The blades (3) are made of a material that absorbs laser energy strongly. The front plate (1), the rear plate (2), and the blades (3) are all made of plastic. The surface of the blades (3) that contacts the grooves (14) is laser-welded to the front plate (1). The front disc (1) facing the rear disc (2) gradually indents towards the central axis of both, and the depth of each part of the groove (14) remains the same. The height of the blade (3) near the central axis of the rear disc (2) is greater than the height of the blade (3) away from the central axis of the rear disc (2). The side of the blade (3) facing the front disc (1) is an arc surface and fits against the inner bottom wall of the groove (14); The impeller manufacturing process includes the following steps: The front plate (1) and the rear plate (2) were molded separately, and the front plate (1) and the rear plate (2) were cast separately. Insert the blade (3) into the corresponding groove (14); Press the front plate (1) and the rear plate (2) together; A laser of a fixed wavelength is selected and applied to the surface where the blade (3) contacts the groove (14), so that the blade (3) is welded to the front plate (1).

2. The impeller according to claim 1, characterized in that: The front disc (1) is made of polycarbonate / polypropylene / polymethyl methacrylate.

3. The impeller according to claim 1, characterized in that: The rear disc (2) and the blade (3) are made of glass fiber reinforced nylon / polyamide / polyphenylene sulfide.

4. The impeller according to claim 1, characterized in that: There is a gap between the end of the blade (3) away from the central axis of the rear disc (2) and the outer peripheral surface of the rear disc (2).

5. The impeller according to claim 1, characterized in that: The blades (3) are equidistantly distributed around the central axis of the rear disc (2), and the side of the blades (3) is configured as an outer arc surface and an inner arc surface. The extended arc of the outer arc surface of the blades (3) gradually converges towards the center of the rear disc (2).

6. The impeller according to claim 5, characterized in that: The curvature of the inner arc surface of the blade (3) is smaller than the curvature of the outer arc surface of the blade (3).

7. The impeller according to claim 5, characterized in that: The vent of the front disc (1) is provided with a first annular protrusion (13), and the vent of the rear disc (2) is provided with a second annular protrusion (23). The diameter of the protruding end of the first annular protrusion (13) is smaller than the diameter of the recessed end of the first annular protrusion (13), and the diameter of the protruding end of the second annular protrusion (23) is the same as the diameter of the recessed end of the second annular protrusion (23).

Images