Stamping forming welded sewage pump impeller and processing method

Abstract

A kind of stamping forming welded sewage pump impeller and processing method.It relates to sewage pump impeller technical field.Solve the problems of many manufacturing defects,high production cost,convenient maintenance and low material utilization rate in prior art casting impeller.The present application includes hub and back cover plate,at least two blade assemblies are uniformly distributed on the surface of the back cover plate;Blade assembly includes inlet edge cylinder,blade and filler,blade is composed of pressure surface and back surface,pressure surface,back surface and inlet edge cylinder form a hollow cavity;Filler is arranged in the hollow cavity.The impeller of the present application realizes active non-destructive dynamic balance compensation,changes the traditional subtraction thinking of relying on polishing surface to remove weight.Introduce the elastic-plastic bending analytical model based on material yield strength and elastic modulus,realize high-precision forming.The hollow blade of the present application reduces weight and increases efficiency,positioning is reliable by welding,anti-winding,anti-abrasion,anti-deformation ability is stronger,manufacturing flexibility is maintained,with economy.

Description

Technical Field

[0001] This invention relates to the field of sewage pump impeller technology, and in particular to improvements in the structure and processing method of sewage pump impellers for conveying media containing solid particles or fibers. Background Technology

[0002] Sewage pumps are widely used in urban drainage, sewage treatment, and industrial wastewater transportation. The reliability and manufacturing cost of their core flow-through component, the impeller, are crucial. Existing sewage pump impellers are primarily manufactured using a one-piece casting method, such as sand casting or precision casting. However, traditional cast impellers have the following inherent drawbacks: First, the casting process has a long production cycle and high mold costs, making it particularly unsuitable for small-batch, multi-specification production. Second, castings are prone to defects such as porosity, shrinkage cavities, and slag inclusions. These defects can become corrosion initiation points and structural weak points in sewage media containing abrasive particles, severely impacting the impeller's service life and reliability. Furthermore, if a part of a one-piece cast impeller (such as the blade inlet edge) is damaged, it usually requires complete replacement, resulting in high maintenance costs and uneconomical practices. In addition, the material utilization rate of the casting process is relatively low, and the optimal hydraulic design of the impeller may be limited by the required shape.

[0003] To address the numerous shortcomings of cast impellers, the industry has begun to explore the use of stamping and welding processes. For example, the patented technology "CN101658999A, A Processing Technology for a Double-Blade Closed Impeller" replaces the traditional casting process by stamping and welding the front cover plate, rear cover plate, and blades separately, achieving a certain degree of impeller thinning and weight reduction. However, this technology still has the following shortcomings in practical applications: First, there is a lack of effective compensation for shape deviations caused by sheet springback during stamping; simply using shaping not only increases the number of steps but also has limited effectiveness. Second, the blades are solid structures, limiting the potential for weight reduction. Third, dynamic balancing relies on the precision of the shape and subsequent weight reduction adjustments, which are limited in precision and irreversible. Fourth, the welding methods are mainly projection welding and argon arc welding, making it difficult to adapt to the quality control requirements of different wall thicknesses and complex joint types.

[0004] In summary, the existing technical measures mentioned above are insufficient to overcome the common technical problems currently faced: First, the blade profile design still relies on casting experience and fails to fully utilize the structural advantages of stamped parts for hydraulic optimization; second, stainless steel and other metal sheets exhibit severe "drawing springback" after stamping, resulting in large gaps in the assembly of split blades and low welding qualification rates; third, the thick hub / inlet edge and the thin stamped blades are prone to burn-through or incomplete welding during welding, making thermal deformation difficult to control; fourth, the dynamic balancing of the impeller after forming mainly relies on grinding to remove weight, which damages the dense layer or wear-resistant coating on the surface of the stamped parts, reducing their service life.

[0005] Therefore, there is an urgent need in this technical field for a sewage pump impeller structure and manufacturing method that can overcome the above-mentioned defects in order to achieve the goals of high efficiency, low cost, high reliability and easy maintenance. Summary of the Invention

[0006] This invention aims to provide a stamped and welded sewage pump impeller and its processing method, to solve the problems of numerous manufacturing defects, high production costs, inconvenient maintenance, and low material utilization in existing cast impellers. By adopting a process of split stamping and combined welding, an impeller product with high structural strength, good corrosion and abrasion resistance, easy local maintenance and replacement, and low manufacturing cost is provided.

[0007] The technical solution of the present invention is: a stamped and welded sewage pump impeller, including a hub and a rear cover plate, wherein at least two blade assemblies are evenly distributed on the surface of the rear cover plate;

[0008] The blade assembly includes an inlet side cylinder, blades, and a filler. The blades are formed by welding a pressure surface and a back surface. Both the pressure surface and the back surface are stamped from metal sheets. The roots of the pressure surface and the back surface are fixedly welded to the cylindrical surface of the inlet side cylinder. The bottom edges of the pressure surface and the back surface, as well as the bottom surface of the inlet side cylinder, are welded to the surface of the rear cover plate, so that the pressure surface, the back surface, and the inlet side cylinder together form a hollow cavity.

[0009] The filler is disposed within the hollow cavity, and a sealing plate is provided on the top surface of the pressure surface and the back surface.

[0010] Furthermore, the wheel hub is machined from metal bar stock; the rear cover plate is a circular metal plate made by stamping process, with a mounting hole in the center.

[0011] Furthermore, stepped grooves for accommodating the pressure surface and the root of the back side are respectively provided on both sides of the inlet cylinder, and the cross-sectional shape of the stepped groove is one of rectangle, trapezoid or arc.

[0012] Furthermore, the filler is an alloy material or a high-performance composite material; the mass of the filler within the hollow cavity is not uniformly distributed.

[0013] This invention discloses a method for processing a stamped and welded sewage pump impeller, comprising the following steps:

[0014] S1. Digital modeling and simulation optimization.

[0015] Establish a three-dimensional parametric model of the impeller, and extract the three-dimensional target design surfaces of the blade pressure surface and back surface based on the material thickness;

[0016] S2. Stamping springback compensation based on analytical model.

[0017] The three-dimensional target design surface extracted in step S1 is discretized into several two-dimensional cross-sectional feature curves along the streamline direction, and the target design radius of curvature of the discrete nodes on each feature curve is extracted. Based on the yield strength of the plate Elastic modulus and plate thickness The mathematical model of elastic-plastic bending springback is used to solve the curvature radius of the die compensation process corresponding to each node. :

[0018] The calculated machining curvature radius of all molds will be compensated. The nodes are refitted in three-dimensional space to generate a three-dimensional profile of the stamping die with reverse compensation.

[0019] S3, Component processing.

[0020] High-precision pressure surface and back surface are machined using the three-dimensional profile of the stamping die with reverse compensation generated in step S2.

[0021] The wheel hub is then formed by turning, the circular rear cover plate with a central mounting hole is formed by stamping, the inlet edge cylinder 3 with the stepped groove is formed by machining on the metal bar, and the sealing plate is formed by stamping.

[0022] S4. Welding and assembly

[0023] The hub is welded and fixed in the center mounting hole of the rear cover plate; the pressure surface is butt-welded to the back side to form a hollow blade; the root of the blade is matched and welded to the stepped groove on the inlet side cylinder; the bottom edge of the blade and the bottom surface of the inlet side cylinder are welded to the rear cover plate.

[0024] During the welding process, segmented energy control is implemented based on the thickness difference of the base material;

[0025] S5. Filling and Closing

[0026] The filler is inserted into the hollow cavity formed by the inlet cylinder, the pressure surface, and the back surface; the sealing plate is welded to the top surface of the hollow cavity to seal it.

[0027] S6, Post-processing

[0028] After welding, the impeller is ground and dynamically balanced.

[0029] Furthermore, the mathematical model for elastic-plastic bending springback in step S2 is as follows:

[0030] Mold compensation machining curvature radius corresponding to each node :

[0031] ,

[0032] The above equation is a nonlinear implicit function equation, where For yield strength, For elastic modulus, The thickness is the plate thickness.

[0033] Furthermore, before the hollow cavity is sealed in step S5, a dynamic balance test is performed on the impeller assembly that has been preliminarily welded to obtain unbalance vector data; based on this data, the required counterweight mass in the hollow cavity of each blade is calculated, and non-equal precise injection of support filling material is performed.

[0034] Furthermore, in step S5, before filling the filler, the inner surface of the hollow cavity is subjected to anti-corrosion treatment.

[0035] Furthermore, in the segmented energy-controlled welding described in step S4, a high-frequency pulse low-heat input mode is used at the edge joint of the thin plate of the blade, and a continuous high-power deep penetration mode is used at the joint of the blade root and the stepped groove of the inlet edge cylinder.

[0036] Furthermore, in step S5, the filler is made of metal powder, and after sealing, an overall heat treatment process is also included to form a metallurgical bond between the powder and the inner wall of the blade.

[0037] This invention overturns the traditional manufacturing path of semi-open impellers, and uses a split stamping and welding process to process sewage pump impellers, which solves the pain points of existing technologies that use castings, such as many defects, high cost, long cycle and non-repairability.

[0038] The impeller of this invention has a hollow blade structure with a filler inside the hollow cavity, which realizes active non-destructive dynamic balance compensation. It changes the traditional subtractive thinking of relying on grinding the surface to reduce weight. By using non-equal amount of support material to fill the hollow cavity of the blade, it can achieve active internal counterweight while enhancing the structural rigidity. It improves the counterweight accuracy, does not damage the surface, and can be repeatedly adjusted.

[0039] The present invention achieves a theoretical breakthrough in the overall forming accuracy of the impeller. Under the technical measure of stamping key components using sheet metal, an elastoplastic bending analytical model based on the yield strength and elastic modulus of the material is introduced. By iteratively solving the nonlinear implicit function equation, the error of stainless steel stamping springback is accurately compensated, thus achieving high-precision forming.

[0040] The hollow blades of this invention reduce weight and increase efficiency, ensure reliable welding positioning, and offer enhanced resistance to entanglement, abrasion, and deformation. They also allow for flexible manufacturing while maintaining economic efficiency. The modular stamping and welding process eliminates the need for expensive integral molds, significantly shortening the R&D cycle and reducing the cost of small-batch production. This makes it particularly suitable for small-batch, multi-variety, and customized sewage pumps. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a three-dimensional schematic diagram of the present invention.

[0043] Figure 2 This is an exploded view of the present invention.

[0044] Figure 3 This is a schematic diagram of the structure of the present invention.

[0045] Figure 4 yes Figure 3 Left view,

[0046] Figure 5 yes Figure 3 Rear view,

[0047] Figure 6 This is a three-dimensional schematic diagram of the blade assembly in this invention.

[0048] Figure 7 This is a schematic diagram of the blade assembly in this invention.

[0049] Figure 8 yes Figure 7 Left view,

[0050] Figure 9 yes Figure 8 Sectional view AA

[0051] Figure 10 This is a flowchart of the processing of this invention;

[0052] In the diagram, 1 is the wheel hub, 2 is the rear cover plate, 3 is the inlet side cylinder, 31 is the stepped groove, 4 is the blade, 41 is the pressure surface, 42 is the back side, 5 is the filler, and 51 is the sealing plate. Detailed Implementation

[0053] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0054] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual images. They should not be construed as limiting the scope of this patent. To better illustrate the embodiments of the present invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0055] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "inner," and "outer" 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 present invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the accompanying drawings are only for illustrative purposes and should not be construed as limiting the present patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0056] It should be noted that, Figure 1-9 Taking a double-bladed impeller as an example, and in which... Figure 2 Only one blade assembly is shown in the image.

[0057] The present invention provides a stamped and welded sewage pump impeller, such as... Figure 1-9 As shown, it includes a hub 1 and a rear cover 2, with at least two blade assemblies evenly distributed on the surface of the rear cover 2;

[0058] The blade assembly includes an inlet side cylinder 3, a blade 4, and a filler 5. The blade 4 is formed by welding a pressure surface 41 and a back surface 42. Both the pressure surface 41 and the back surface 42 are formed by stamping metal sheets. The roots of the pressure surface 41 and the back surface 42 are fixedly welded to the cylindrical surface of the inlet side cylinder 3. The bottom edges of the pressure surface 41 and the back surface 42, as well as the bottom surface of the inlet side cylinder 3, are welded to the surface of the rear cover plate 2, so that the pressure surface 41, the back surface 42, and the inlet side cylinder 3 together form a hollow cavity.

[0059] A filler 5 is installed inside the hollow cavity, and a sealing plate 51 is provided on the top surface of the pressure surface 41 and the back surface 42. During manufacturing, the rear cover plate 2, the blades 4 (pressure surface 41 and back surface 42), and the sealing plate 51 are made of stainless steel or duplex stainless steel.

[0060] Furthermore, the wheel hub 1 is machined from a metal bar; the rear cover plate 2 is a circular metal plate made by stamping, with a mounting hole in the center. The wheel hub 1 is made of the same material as the aforementioned rear cover plate 2 and blade 4.

[0061] Furthermore, stepped grooves 31 are respectively provided on both sides of the inlet cylinder 3 to accommodate the pressure surface 41 and the root of the back surface 42. The cross-sectional shape of the stepped grooves 31 is rectangular, trapezoidal, or arc-shaped. The inlet cylinder 3 is also made of the same material. The purpose of the stepped grooves 31 is to ensure that the pressure surface 41 and the root of the back surface 42 of the blade 4 have sufficient contact area, so that the welding positioning is reliable.

[0062] Furthermore, the filler 5 is an alloy material or a high-performance composite material, and the mass of the filler 5 within the hollow cavity is not uniformly distributed.

[0063] The alloy materials used for filler 5, such as metal welding wire and metal powder, and high-performance composite materials, such as polymer composite resin materials, are selected by those skilled in the art based on the above information and their own conditions. These materials have a certain density and can be cured and firmly bonded to the hollow cavity. As for non-uniform distribution, such as... Figure 8 As shown, those skilled in the art need to arrange the filler 5 according to the balance test results.

[0064] This invention discloses a method for processing a stamped and welded sewage pump impeller, such as... Figure 10 As shown, it includes the following steps:

[0065] S1. Digital modeling and simulation optimization.

[0066] A three-dimensional parametric model of the impeller is established, and the three-dimensional target design surfaces of the blade pressure surface 41 and back surface 42 are extracted based on the material thickness.

[0067] S2. Stamping springback compensation based on analytical model.

[0068] This step requires calculating the tensile springback amount, then generating the mold surface for reverse compensation, and then stamping the pressure surface 41 and the back surface 42; calculating the tensile springback amount is a conventional technique in the field and will not be described in detail in this invention.

[0069] The specific steps for generating the mold surface for reverse compensation are as follows: the three-dimensional target design surface extracted in step S1 is discretized into several two-dimensional cross-sectional feature curves along the streamline direction, and the target design radius of curvature of the discrete nodes on each feature curve is extracted. Based on the yield strength of the plate Elastic modulus and plate thickness The mathematical model of elastic-plastic bending springback is used to solve the curvature radius of the die compensation process corresponding to each node. :

[0070] The calculated machining curvature radius of all molds will be compensated. The nodes are refitted in three-dimensional space to generate a three-dimensional profile of the stamping die with reverse compensation.

[0071] The mathematical model for elastic-plastic bending springback in this step is:

[0072] Mold compensation machining curvature radius corresponding to each node :

[0073] ,

[0074] The above equation is a nonlinear implicit function equation, where For yield strength, For elastic modulus, The thickness is the plate thickness.

[0075] The aforementioned nodes refer to discrete points on the two-dimensional cross-sectional feature curves used to calculate the curvature radius of the mold compensation section after discretizing the target design surface of the blade.

[0076] The specific solution method is as follows:

[0077] Constructing the objective function: By rearranging the terms in the above equation and setting it equal to zero, we obtain the following equation:

[0078] ,

[0079] Set initial value: Set initial That is, assuming no rebound,

[0080] Iterative optimization: using computer programs to automatically find... Closest to 0 value,

[0081] The calculated machining curvature radius of all molds will be compensated. The nodes are refitted in three-dimensional space to generate a three-dimensional profile of the stamping die with reverse compensation.

[0082] S3, Component processing.

[0083] Using the three-dimensional profile of the stamping die with reverse compensation generated in step S2, a high-precision pressure surface 41 and back surface 42 are machined;

[0084] Next, the hub 1 is formed by turning, the circular rear cover plate 2 with a central mounting hole is formed by stamping, the inlet edge cylinder 3 with stepped grooves 31 is formed by machining on the metal bar, and the sealing plate 51 is formed by stamping. In this step, the machining of the hub 1, the rear cover plate 2 and the inlet edge cylinder 3 can be done in advance, while the sealing plate 51, because it needs to match the enclosing shape of the blade 4, needs to be precisely machined after the three-dimensional surface is generated.

[0085] S4. Welding and assembly

[0086] Before welding, the relevant parts need to be treated with anti-corrosion measures, and then segmented energy control welding is used.

[0087] The hub 1 is welded and fixed in the center mounting hole of the rear cover plate 2; the pressure surface 41 and the back surface 42 are butt welded to form a hollow blade 4; the root of the blade 4 is matched and welded to the stepped groove 31 on the inlet side cylinder 3; the bottom edge of the blade 4 and the bottom surface of the inlet side cylinder 3 are welded to the rear cover plate 2.

[0088] During the welding process, segmented energy control is implemented based on the thickness difference of the base material. Gas shielded welding or laser welding is preferred for welding.

[0089] Furthermore, in the segmented energy-controlled welding of step S4, a high-frequency pulse low-heat input mode is used at the butt joint of the thin plate edge of the blade 4, and a continuous high-power deep penetration mode is used at the junction of the blade root and the stepped groove 31 of the inlet edge cylinder 3.

[0090] S5. Filling and Closing

[0091] This step requires completing the following technical tasks: performing dynamic balancing tests on the impeller assembly and obtaining unbalance vector data; calculating the counterweight mass of each cavity; injecting non-uniform support filler; and sealing and welding the top surface. Details are as follows:

[0092] Fill the hollow cavity formed by the inlet side cylinder 3, the pressure surface 41 and the back surface 42 with filler 5; weld the sealing plate 51 to the top surface of the hollow cavity to seal it.

[0093] Before sealing the hollow cavity in step S5, a dynamic balance test is performed on the preliminarily welded impeller assembly to obtain unbalance vector data. Based on this data, the required counterweight mass in the hollow cavity of each blade is calculated, and the non-equal amount of support filler 5 is precisely injected. The dynamic balance test of the impeller semi-finished product in this step is achievable by those skilled in the art according to the purpose of this invention, and will not be elaborated further in this invention.

[0094] Furthermore, in step S5, before filling the filler 5, the inner surface of the hollow cavity is subjected to anti-corrosion treatment. The purpose is to prevent corrosion from causing the filler 5 to fail to bond with the rear cover plate 2, pressure surface 41 and back surface 42, resulting in loosening.

[0095] Furthermore, in step S5, when the filler 5 is made of metal powder, the sealing process also includes an overall heat treatment process to form a metallurgical bond between the powder and the inner wall of the blade. Of course, when using metal powder as the filler, it is necessary to select one with a relatively low melting point (that is, it can be "melted" to a low degree in the heat treatment process, that is, the whole can be sintered into one piece and bonded to the bottom and sides, while maintaining a non-equilibrium state).

[0096] S6, Post-processing

[0097] After welding, the impeller is ground to repair the weld seam and the dynamic balance of the finished product is checked.

[0098] The manufacturing process of the present invention will be further described below with reference to the embodiments.

[0099] Example 1

[0100] Reference Figures 1 to 10 This embodiment provides a stamped and welded impeller for a medium-sized sewage pump, which has three blades 4.

[0101] The wheel hub 1 is machined from 45# steel bar and the surface is treated with rust prevention.

[0102] The rear cover plate 2 is made of 304 stainless steel plate with a thickness of 6mm. It is made into a round flat plate through stamping processes such as blanking, punching, and shaping. The center hole and the wheel hub 1 are fixed by interference fit and peripheral fillet welding.

[0103] The imported cylindrical column 3 is machined from 304 stainless steel bar stock, and six stepped grooves 31 with trapezoidal cross sections are evenly distributed on its outer circle.

[0104] The blade 4 is made of 304 stainless steel plate with a thickness of 3mm, with a pressure surface 41 and a back surface 42 stamped out respectively. The edges of the pressure surface 41 and the back surface 42 are aligned and continuously welded by argon arc welding to form a closed frame of the hollow blade 4. Then, a sealing plate 51 with process holes is welded on the top surface of the frame of the hollow blade 4 to form a single blade 4.

[0105] During assembly, the root parts of the three individual blades 4 are first inserted into the stepped grooves 31 of the inlet cylinder 3, and plug welding and fillet welding are performed from both sides to ensure firmness, forming the blade 4 assembly. Then, this assembly is aligned with the rear cover plate 2 of the already installed hub 1, and the bottom edge of each blade 4 assembly is welded to the rear cover plate 2.

[0106] Subsequently, 304 stainless steel welding wire is filled into the cavity formed by each blade 4 and the inlet edge cylinder 3 through the reserved process hole as filler 5. Finally, the process hole is welded closed with a circular cover plate.

[0107] It should be noted that digital modeling and optimization are required when fabricating the pressure surface 41 and back surface 42 of blade 4 in this embodiment. Specifically, the researchers first establish a three-dimensional parametric model of the impeller in the software. The pressure cloud map of the blade during operation is extracted using CFD fluid simulation software. Based on the force distribution, the software sets the optimization parameters for the hollow cavity: the central part experiences greater force, so a larger gap is reserved to accommodate more support material; the tail edge tapers into a streamlined shape. Subsequently, the optimized three-dimensional target surfaces of the blade pressure surface 41 and back surface 42 are output.

[0108] Then, based on the analytical model, the die springback compensation and stamping process involves the following steps:

[0109] Surface discretization: Extract the 3D target surface generated by S1, and discretize the target surface into several 2D cross-sectional feature curves along the streamline direction. Extract the target design radius of curvature of the discrete nodes on each feature curve. .

[0110] Springback calculation, thickness selection 304 stainless steel plate (yield strength) elastic modulus Using the established elastoplastic bending springback model:

[0111]

[0112] The above high-order nonlinear equations were solved using Newton's iterative method via a computer program, yielding the compensated machining radius of curvature for each discrete point on the mold surface. .

[0113] All calculated nodes In three-dimensional space, the NURBS algorithm is used to perform smooth surface fitting, generating a three-dimensional profile of the stamping die with reverse compensation.

[0114] Precision stamping involves machining a die based on the compensation profile to form the sheet metal. After unloading, the sheet metal exhibits the expected elastic recovery, precisely springing back to the target curved surface. Simultaneously, a 1mm high positioning boss is pressed out at the edge.

[0115] Positioning and segmented variable-energy welding are used to insert the roots of six formed hollow blade units into stepped grooves 31 of the imported edge cylinder 3, which is machined from 304 stainless steel bars. Fiber laser welding is employed: at the thin plate edges where the two halves of the blade meet, a high-frequency pulse low-heat input mode is used to prevent intergranular corrosion and thermal deformation; when moving to the thickness interface between the stepped groove 31 and the blade root, it automatically switches to a continuous high-power deep penetration mode to ensure a robust mechanical structure.

[0116] Dynamic pre-filling and balance compensation are employed. The unsealed impeller assembly is clamped onto a dynamic balancing test bench, and a specific imbalance and phase angle are measured. Based on this, a counterweight scheme is calculated. For the area on the opposite side where the imbalance occurs, an excess ratio of a mixture of polymer resin and metal powder is injected into the cavity of the corresponding numbered blade; the remaining blades are injected only with the standard amount to maintain basic stiffness (i.e., achieving an unequal distribution of the support filler 5). After room temperature curing, the sealing plate 51 is placed over the end opening of the blade 4 and fully welded circumferentially.

[0117] Post-processing: Dynamic balancing was re-tested. Since the impeller had already undergone internal structural counterweighting in S4, it directly achieved a G6.3 level of balancing accuracy, eliminating the need for any grinding or weight removal on the flow surface. Finally, all welds were polished to complete the overall manufacturing process.

[0118] Of course, the finished product of this invention can be heat-treated after molding to eliminate the internal stress formed by stamping and welding.

[0119] Example 2

[0120] This embodiment optimizes the materials and processes based on Embodiment 1, and is suitable for highly corrosive media.

[0121] The material of the rear cover plate 2 and blade 4 was changed to 2205 duplex stainless steel to improve its resistance to chloride corrosion.

[0122] The filler 5 uses a mixture of epoxy resin and ceramic powder as a potting material. Before filling, the inner cavity of the blade 4 is sandblasted and passivated, and then the liquid potting material is injected and cured at room temperature.

[0123] All welding processes employ pulse welding to improve welding efficiency, control heat input, and reduce deformation.

[0124] The hub 1 has a centrally machined shaft hole and keyway for mounting on the drive shaft and transmitting torque.

[0125] Example 3

[0126] This embodiment demonstrates the adaptability of the invention. For highly abrasive operating conditions, the pressure surface 41 and back surface 42 of the blade 4 are made of wear-resistant steel plate, while the rear cover plate 2 and the inlet edge cylinder 3 are still made of ordinary stainless steel. A layer of wear-resistant ceramic coating can be pre-sprayed onto the surface of the blade 4 before filling with metal powder as filler 5. This composite structure can significantly improve the wear resistance of the flow surface while ensuring overall corrosion resistance.

[0127] It should be stated that the above-described specific embodiments are merely preferred embodiments of the present invention and the technical principles employed. Those skilled in the art should understand that various modifications, equivalent substitutions, and variations can be made to the present invention based on the technical content disclosed in this application. However, such variations, as long as they do not depart from the spirit of the present invention, should be within the protection scope of the present invention. Furthermore, some terminology used in this specification and claims is not limiting but merely for ease of description.

Claims

1. A stamped and welded sewage pump impeller, comprising a hub (1) and a rear cover plate (2), characterized in that, At least two blade assemblies are evenly distributed on the surface of the rear cover plate (2); The blade assembly includes an inlet side cylinder (3), a blade (4), and a filler (5). The blade (4) is formed by welding a pressure surface (41) and a back surface (42). Both the pressure surface (41) and the back surface (42) are formed by stamping metal sheets. The roots of the pressure surface (41) and the back surface (42) are fixedly welded to the cylindrical surface of the inlet side cylinder (3). The bottom edges of the pressure surface (41) and the back surface (42) and the bottom surface of the inlet side cylinder (3) are welded to the surface of the rear cover plate (2), so that the pressure surface (41), the back surface (42), and the inlet side cylinder (3) together form a hollow cavity. The filler (5) is provided in the hollow cavity, and a sealing plate (51) is provided on the top surface of the pressure surface (41) and the back surface (42).

2. The stamped and welded sewage pump impeller according to claim 1, characterized in that, The wheel hub (1) is machined from metal bar stock; the rear cover plate (2) is a circular metal plate made by stamping process, with a mounting hole in the center.

3. The stamped and welded sewage pump impeller according to claim 1, characterized in that, The two sides of the inlet cylinder (3) are respectively provided with stepped grooves (31) for accommodating the pressure surface (41) and the root of the back surface (42). The cross-sectional shape of the stepped grooves (31) is one of rectangle, trapezoid or arc.

4. The stamped and welded sewage pump impeller according to claim 1, characterized in that, The filler (5) is an alloy material or a high-performance composite material; the mass of the filler (5) in the hollow cavity is not equally distributed.

5. The processing method of a stamped and welded sewage pump impeller as described in claim 3, characterized in that, Includes the following steps: S1. Digital modeling and simulation optimization. Establish a three-dimensional parametric model of the impeller, and extract the three-dimensional target design surfaces of the blade pressure surface (41) and back surface (42) based on the material thickness; S2. Stamping springback compensation based on analytical model. The three-dimensional target design surface extracted in step S1 is discretized into several two-dimensional cross-sectional feature curves along the streamline direction, and the target design radius of curvature of the discrete nodes on each feature curve is extracted. Based on the yield strength of the plate Elastic modulus and plate thickness The mathematical model of elastic-plastic bending springback is used to solve the curvature radius of the die compensation process corresponding to each node. : The calculated machining curvature radius of all molds will be compensated. The nodes are refitted in three-dimensional space to generate a three-dimensional profile of the stamping die with reverse compensation. S3, Component processing. Using the three-dimensional profile of the stamping die with reverse compensation generated in step S2, a high-precision pressure surface (41) and back surface (42) are machined. The wheel hub (1) is then formed by turning, the circular rear cover plate (2) with a central mounting hole is formed by stamping, the inlet edge cylinder (3) with the stepped groove (31) is formed on the metal bar by machining, and the sealing plate (51) is formed by stamping. S4. Welding and assembly The hub (1) is welded and fixed in the center mounting hole of the rear cover plate (2); the pressure surface (41) is butt-welded to the back surface (42) to form a hollow blade (4); the root of the blade (4) is matched and welded to the stepped groove (31) on the inlet side cylinder (3); the bottom edge of the blade (4) and the bottom surface of the inlet side cylinder (3) are welded to the rear cover plate (2); During the welding process, segmented energy control is implemented based on the thickness difference of the base material; S5. Filling and Closing The filler (5) is filled into the hollow cavity formed by the inlet side cylinder (3), the pressure surface (41) and the back surface (42); the sealing plate (51) is welded to the top surface of the hollow cavity to seal it; S6, Post-processing After welding, the impeller is ground and dynamically balanced.

6. The processing method of a stamped and welded sewage pump impeller according to claim 5, characterized in that, The mathematical model for elastic-plastic bending springback in step S2 is as follows: Mold compensation machining curvature radius corresponding to each node : ， The above equation is a nonlinear implicit function equation, where For yield strength, For elastic modulus, For plate thickness, R' is the target design curvature radius of the discrete node on the characteristic curve, and R is the compensation machining curvature radius corresponding to each discrete point on the mold surface.

7. The processing method of a stamped and welded sewage pump impeller according to claim 5, characterized in that, Before the hollow cavity is sealed in step S5, the impeller assembly that has been preliminarily welded is subjected to dynamic balance test to obtain unbalance vector data; based on the data, the required counterweight mass in the hollow cavity of each blade is calculated, and the non-equal amount of support filler (5) is precisely injected.

8. The processing method of a stamped and welded sewage pump impeller according to claim 5, characterized in that, In step S5, before filling the filler (5), the inner surface of the hollow cavity is subjected to anti-corrosion treatment.

9. A method for processing a stamped and welded sewage pump impeller according to claim 5, characterized in that, In the segmented energy control welding described in step S4, a high-frequency pulse low-heat input mode is used at the thin plate edge joint of the blade (4), and a continuous high-power deep penetration mode is used at the joint of the blade root and the stepped groove (31) of the inlet edge cylinder (3).

10. The processing method of a stamped and welded sewage pump impeller according to claim 5, characterized in that, In step S5, the filler (5) is made of metal powder, and after sealing, it also includes an overall heat treatment process to make the powder form a metallurgical bond with the inner wall of the blade.

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