Cage rotor and method of manufacturing the same, asynchronous motor, fan

Abstract

This application provides a squirrel-cage rotor and its manufacturing method, an asynchronous motor, and a fan. The manufacturing method includes: assembling a rotor core, several guide bars, and two end rings into a welding state, wherein the two end rings are respectively positioned on the two end faces of the rotor core, and the first plane of each end ring contacts the end face of the rotor core; the several guide bars pass through a first through slot on the rotor core one-to-one, and the end of each guide bar is located inside a second through slot on the end ring; the second through slot penetrates the first plane and the second plane of the end ring, and the opening shape of the second through slot on the first plane matches the cross-sectional shape of the guide bar, with the opening area on the second plane being larger than the opening area on the first plane; and performing a fusion welding operation using solder within the groove formed by the end faces of the guide bars and the inner surface of the second through slot, wherein during the fusion welding process, the second plane of each end ring is higher than the first plane. The technical solution of this application can significantly improve the electrical conductivity of the squirrel-cage rotor.

Description

Technical Field

[0001] This application belongs to the field of asynchronous motor technology, specifically relating to cage rotors and their manufacturing methods, asynchronous motors and fans. Background Technology

[0002] An asynchronous motor (also known as an induction motor) is a widely used AC motor. When AC current is applied to its stator windings, a rotating magnetic field is generated. This magnetic field cuts the rotor windings, inducing electromotive force and current in the rotor circuit. The current-carrying rotor conductors are subjected to electromagnetic force in the rotating magnetic field, thereby driving the rotor to rotate. Since the rotor speed is always lower than the synchronous speed of the rotating magnetic field (there is a "slip"), it is called an asynchronous motor.

[0003] The rotor of an asynchronous motor typically uses a cage structure, with the core components being the rotor core and the cage windings. Several conductive bars (mostly made of aluminum or copper) are installed in the axial slots of the rotor core. At both ends of the core, two conductive end rings (usually made of the same material as the bars) are used to short-circuit all the bars, forming a self-closed cage-like conductive circuit structure. This type of rotor is usually called a cage rotor or squirrel-cage rotor.

[0004] For small and medium-sized motors, squirrel-cage rotors are usually manufactured using an aluminum casting process. The iron core is placed inside a mold, and then molten aluminum is poured directly into the space between the iron core and the mold cavity to form the guide bars, end rings, and even fan blades in one step. For large motors, due to the high cost of molds, a manufacturing method is usually adopted in which the guide bars are inserted one by one through each slot of the rotor iron core, and the two ends of the guide bars are inserted through two end rings respectively. Then the guide bars and end rings are welded together.

[0005] However, the existing welding manufacturing method for cage rotors has at least the following problems: On the one hand, the contact surface between the conductor bars and the end rings is often parallel to the axial direction, resulting in a small area of ​​connection by welding (e.g., only by weld seam), insufficient welding strength, and easy detachment; on the other hand, since the aluminum, copper and other metals used in the conductor bars and end rings are prone to oxidation and form a dense and non-conductive oxide layer on their surface, the oxidation at the contact surface between the conductor bars and end rings is not easy to remove during welding, which significantly increases the contact resistance at the joint, thereby causing problems such as local overheating at the joint and increased power loss, which seriously affects the performance of the rotor winding.

[0006] To address the aforementioned issues, existing optimized welding methods for the squirrel-cage rotors of large asynchronous motors typically include brazing or induction brazing, which allows the solder to fully fill the gap between the guide bars and end rings, forming a larger connection surface. In addition, further measures such as mechanical grinding (wire brush, scraping), chemical cleaning, ultrasonic film removal, or welding under inert gas protection (such as argon) are employed to reduce the impact of oxidation on the contact surface. These additional measures undoubtedly significantly increase manufacturing costs and difficulty, and the regeneration rate of the oxide layer is extremely fast (e.g., the formation rate of the alumina layer is on the order of milliseconds), placing extremely high demands on the process window. Summary of the Invention

[0007] To address the problems existing in the welding and manufacturing process of cage rotors, this application provides a method for manufacturing a cage rotor through embodiments, the method comprising the following operations: The rotor core, several guide bars, and two end rings are assembled into a welding state. The two end rings are respectively positioned on the two end faces of the rotor core, and the first plane of each end ring contacts the end face of the rotor core. The several guide bars pass through several first through slots on the rotor core one by one, and the end of each guide bar is located inside the second through slot on the end ring. The second through slot penetrates the first plane and the second plane of the end ring. Furthermore, the opening shape of the second through slot on the first plane matches the cross-sectional shape of the guide bar, and the opening area on the second plane is larger than the opening area on the first plane. A fusion welding operation is performed using solder within the groove formed by the end face of the guide bar and the inner surface of the second through groove, wherein the second plane of each end ring is set to be higher than the first plane during the fusion welding process.

[0008] This application also provides a cage rotor through embodiments, including a rotor core, two end rings and a plurality of guide bars, and further including welded parts in number twice the number of guide bars; Two end rings are respectively positioned on the two end faces of the rotor core, and the first plane of each end ring contacts the end face of the rotor core. A plurality of guide bars pass through a plurality of first through slots on the rotor core in a corresponding manner, and the end of each guide bar is located inside the second through slot on the end ring. The second through slot penetrates the first plane and the second plane of the end ring, and the opening shape of the second through slot on the first plane matches the cross-sectional shape of the guide bar, and the opening area on the second plane is larger than the opening area on the first plane. The welded part is fixedly connected to the end face of the guide bar and the inner surface of the second through groove, and there are no metal oxide components at the positions where the welded part contacts the end face of the guide bar and the positions where the welded part contacts the inner surface of the second through groove.

[0009] This application also provides an asynchronous motor through embodiments, including a rotor, a stator, a motor shaft, a rotor support portion, and a stator support portion. The rotor is coaxially fixedly connected to the motor shaft through the rotor support portion, the stator is fixedly connected to the stator support portion, and the motor shaft is rotatably connected to the stator support portion through bearings. The rotor is the aforementioned cage rotor.

[0010] This application also provides a fan through embodiments, including: The aforementioned asynchronous motor; Several blades are spaced apart circumferentially and are fixedly connected to the rotor and motor shaft of the asynchronous motor.

[0011] Compared to existing cage rotor manufacturing methods, the cage rotor manufacturing method provided in this application sets the second through groove through the end ring as a constant cross-section region plus a variable cross-section region. The constant cross-section region is used for positioning during the assembly process of the guide bar and the end ring, while the variable cross-section region, together with the end face of the guide bar, forms a beveled groove. Since the metal oxide layer of this beveled groove has no obstruction above it during the fusion welding process, it can be ensured that as welding proceeds, the welding wire, the guide bar, and the pure metal part in the end ring are welded together. Using this method, there are no high-resistance metal oxide components between the final welded part and the joint of the guide bar and the end ring, which can ensure the formation of a good current path between the guide bar -> welded part -> end ring. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of an existing cage rotor; Figure 2 This is a schematic diagram of brazing the guide bars and end rings in an existing cage rotor manufacturing method. Figure 3 for Figure 2 The diagram shows a cross-sectional view of the distribution of the end ring, guide bar, and brazing filler metal between the end ring and guide bar during the brazing process. Figure 4 This is a schematic diagram of a method for manufacturing a cage rotor according to an embodiment of this application; Figure 5 This is a three-dimensional structural diagram of the rotor core provided according to an embodiment of this application; Figure 6 This is a top view of the rotor core provided according to an embodiment of this application; Figure 7 This is a three-dimensional structural diagram of the end ring provided according to an embodiment of this application; Figure 8 This is a three-dimensional structural schematic diagram and a top view of the end ring provided according to an embodiment of this application; Figure 9 This is a cross-sectional view of the end ring provided according to an embodiment of this application; Figure 10 This is a schematic diagram of a guide bar provided according to an embodiment of this application; Figure 11 This is a schematic diagram of the first opening and the second opening of the end ring provided according to an embodiment of this application; Figure 12 This is an exploded view of the assembly relationship of the rotor core, conductor bars, and end rings according to an embodiment of this application; Figure 13 This is a schematic diagram of a rotor core, conductor bars, and end ring in a state to be welded, according to an embodiment of this application. Figure 14 This is a schematic diagram showing the state in which the guide bar is not assembled in the second through groove of the end ring according to an embodiment of this application; Figure 15 This is a schematic diagram showing the guide bar, according to an embodiment of this application, assembled into the second through groove of the end ring and in a state awaiting welding. Figure 16 This is a schematic diagram showing the state of the end ring, guide bar, and welded part during the fusion welding operation according to the embodiments of this application; Figure 17 This is a schematic diagram showing the state of the end ring, guide bar, and welded part after fusion welding according to the embodiments of this application; Figure 18 This is a schematic diagram of a cage rotor provided according to an embodiment of this application; Figure 19 This is a schematic diagram illustrating the usage state of the welding tooling provided according to the embodiments of this application; Figure 20 This is a partial sectional view of the welding fixture provided in the embodiments of this application, showing its usage state. Figure 21 This is a partially enlarged schematic diagram of a rotor core and end ring with an air-cooling channel according to an embodiment of this application; Figure 22 This is a schematic diagram of an asynchronous motor provided according to an embodiment of this application; Figure 23 A cross-sectional view of an asynchronous motor provided according to an embodiment of this application; Figure 24 This is a schematic diagram of a fan provided according to an embodiment of this application.

[0013] Numbers in the diagram 1: Rotor core, 11: Inner wall of rotor core, 12: Outer wall of rotor core, 13: First through slot, 131: Opening, 14: Positioning slot, 15: Third through slot, 2: End ring, 21: First plane, 22: Second plane, 23: Second through slot, 231: Constant cross-section region, 232: Variable cross-section region, 241: First inner surface, 242: Second inner surface, 251: First opening, 252: Second opening, 26: Fourth through slot, 3: Guide bar, 31: Guide bar body, 32: Protrusion, 33: End face, 4: Welding part, 5: Welding fixture, 51: Handle, 600: Asynchronous motor, 61: Stator, 62: Rotor, 63: Motor shaft, 64: Stator support part, 65: Rotor support part, 66: Bearing seat, 67: Bearing, 68: Lead wire, 700: Axial flow blade. Detailed Implementation

[0014] The present application will now be further described based on preferred embodiments and with reference to the accompanying drawings.

[0015] In the description of the embodiments of this application, it should be noted that the terms "upper," "lower," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationships commonly used when the product of this application is in use, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. Furthermore, in the description of this application, the terms "first," "second," etc., are used to distinguish different units, but these are not limited by the manufacturing order, nor should they be construed as indicating or implying relative importance. Their names may differ in the detailed description and claims of this application. In addition, for ease of understanding, various components in the drawings have been enlarged or reduced, but this is not intended to limit the scope of protection of this application.

[0016] The vocabulary used in this specification is for illustrative purposes and is not intended to limit the scope of this application. It should also be noted that, unless otherwise expressly specified and limited, the terms "set," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, a direct connection, or an indirect connection via an intermediate medium; or they can refer to the internal communication between two components. Those skilled in the art will understand the specific meaning of these terms in this application.

[0017] Figure 1 A schematic diagram of an existing asynchronous motor rotor manufactured using welding methods is shown, such as... Figure 1As shown, a through groove is provided on the end ring, which runs through both end faces. After the guide bar is inserted into the through groove, the contact area between the guide bar and the end ring is welded with solder.

[0018] Since the contact surface between the through groove and the guide bar is parallel to the axial direction, the solder can only weld the narrow gap formed on the end face of the end ring after the guide bar contacts the end ring. Obviously, this welding method has low strength and is prone to causing the guide bar to fall off the end ring. In addition, it cannot remove the oxide layer on the surface of the guide bar and the through groove of the end ring.

[0019] Figure 2 This diagram illustrates the brazing of the guide bars and end rings in another existing method for manufacturing a cage rotor. Figure 3 This is a cross-sectional view showing the distribution of the end ring, guide bar, and brazing filler metal between the end ring and guide bar during the brazing process of this method.

[0020] like Figure 2 , Figure 3 As shown, during the welding process, the side of the end ring facing the rotor core faces upwards, and a non-through groove is formed on this side for the guide bar to be inserted. The end face of the guide bar has an undulating shape. After being inserted into the non-through groove, there is space for the brazing filler metal to flow between the end face of the guide bar and the bottom surface of the non-through groove. The bottom surface dimension of the non-through groove is set to be larger than the cross-sectional dimension of the guide bar, so that after the guide bar and the end ring are welded, more areas are formed through the contact of the brazing filler metal, and some contact surfaces are undulating, which significantly increases the connection strength between the guide bar and the end ring.

[0021] However, for Figure 2 , Figure 3 The method shown still cannot solve the problem of areas with significantly increased resistance in the cage winding caused by oxide layer. For example, between the end face of the conductor bar and the bottom surface of the non-through slot of the end ring, the end face of the conductor bar and the bottom surface of the non-through slot are heated and melted as the brazing temperature increases, but the oxide layer on their surface cannot be removed. Therefore, after the welding is completed and cooled, there is still high resistance in the area, which significantly affects the flow of current in the cage winding.

[0022] To address the aforementioned issues, this application improves the structure and manufacturing method of existing cage rotors to simultaneously enhance their strength and electrical conductivity.

[0023] Figure 4 This is a schematic diagram of a method for manufacturing a cage rotor according to an embodiment of this application, as shown below. Figure 4 As shown, the manufacturing method includes the following operations: Operation 1: Assemble the rotor core, several guide bars, and two end rings into a welding-ready state. The two end rings are respectively positioned on the two end faces of the rotor core, and the first plane of each end ring contacts the end face of the rotor core. The several guide bars pass through several first through slots on the rotor core one by one, and the end of each guide bar is located inside the second through slot on the end ring. The second through slot penetrates the first plane and the second plane of the end ring. Furthermore, the opening shape of the second through slot on the first plane matches the cross-sectional shape of the guide bar, and the opening area on the second plane is larger than the opening area on the first plane. Operation 2 involves using solder to perform a fusion welding operation within the groove formed by the end face of the guide bar and the inner surface of the second through groove, wherein the second plane of each end ring is set to be higher than the first plane during the fusion welding process.

[0024] The following combination Figures 4 to 14 The accompanying drawings provide a detailed explanation of the implementation details of Operation 1 and Operation 2.

[0025] Assembly of rotor core, conductor bars, and end rings Operation 1 is used to assemble the rotor core 1, guide bar 3 and end ring 2 into a state to be welded; Figure 5 A three-dimensional structural schematic diagram of the rotor core 1 in some embodiments is shown, with an enlarged view of circle A. Figure 6 A partial top view of the rotor core 1 is shown in some embodiments. Figure 7 A three-dimensional structural schematic diagram of the end ring 2 as viewed from one side of the second plane 22 in some embodiments is shown, with a magnified view of circle B in the figure; Figure 8 The diagrams show a three-dimensional view of the end ring 2 as viewed from one side of the first plane 21 (left) and a top view of the end ring 2 as viewed from one side of the second plane 22 (right). Figure 9 A cross-sectional view of the end ring 2 is shown in some embodiments, with an enlarged view of the circle D therein, wherein the cutting line is... Figure 8 CC line in the middle; Figure 10 A three-dimensional structural schematic diagram (left) and a top view (right) of the guide strip 3 are shown in some embodiments. 11 shows schematic diagrams of the first opening and the second opening in two different embodiments. Figure 12 An exploded view of the assembly relationship of the rotor core 1, multiple guide bars 3, and two end rings 2 is shown in some embodiments. Figure 13 The diagram shows a rotor core 1, guide bars 3, and end ring 2 in a state awaiting welding after assembly in some embodiments. The structure and assembly process of the rotor core 1, end ring 2, and guide bars 3 are described in detail below with reference to the accompanying drawings.

[0026] a. Structure of rotor core 1 As shown in the figure, the rotor core 1 is generally in the shape of an axially extending ring. Without loss of generality, the axial height of the rotor core 1 can be denoted as... Between the inner wall 11 and the outer wall 12 of the rotor core 1, a first through groove 13 is provided circumferentially at equal intervals. The first through groove 13 is configured to allow the guide bar 3, which will be described later, to pass through axially. Therefore, the shape of its radial cross section is consistent with the radial cross section shape of the guide bar 3, which will not change along the axial direction, so as to facilitate the guide bar to pass through the first through groove 13.

[0027] In some preferred embodiments, as shown in the figure, the first through groove 13 forms an opening 131 on the inner wall 11 of the rotor core 1. By setting this opening, the shape of the first through groove 13 can undergo slight elastic deformation during the process of assembling the guide bar 3 to the rotor core 1, thereby better adapting to the assembly of the guide bar 3 and avoiding the difficulty of sliding the guide bar 3 in the first through groove 13 due to excessive friction between the surface of the guide bar 3 and the first through groove 13.

[0028] The rotor core 1 can be manufactured using various manufacturing methods known to those skilled in the art. For example, the inner wall 11, outer wall 12, and several first through slots 13 can be punched into a silicon steel sheet (preferably, after the silicon steel sheet is punched, an insulating thin layer can be coated on its surface to suppress eddy currents), and then multiple silicon steel sheets are aligned and stacked to a height of [missing information]. Thus, rotor core 1 is obtained.

[0029] Preferably, in order to facilitate the stacking and positioning of multiple silicon steel sheets, a number of positioning grooves 14 can be provided on the outer wall 12 of the rotor core 1. The positioning plate is embedded in the positioning grooves 14 to provide accurate positioning for the stacking and manufacturing of multiple silicon steel sheets.

[0030] b. Structure of end ring 2 As shown in the figure, end ring 2 also has an axially extending ring shape. Without loss of generality, the total axial height of end ring 2 can be denoted as... Between the inner and outer walls of the end ring 2, axially penetrating second through grooves 23 are provided at equal intervals along the circumference. The number, radial position, and circumferential spacing of the second through grooves 23 are consistent with those of the first through groove 13.

[0031] Unlike the first through groove 13, the second through groove 23 provided on the end ring 2 includes two interconnected parts: a constant cross-section region 231 and a variable cross-section region 232.

[0032] Referring to the accompanying drawings, the equal cross-section region 231 is surrounded by the first inner surface 241 extending along the axial direction, and the cross-sectional shape of the equal cross-section region 231 is consistent with the radial cross-sectional shape of the guide bar 3 described later. The first inner surface 241 intersects with the first plane 21 of the end ring 2 to form an open first opening 251. Obviously, the shape of the first opening 251 is also consistent with the cross-sectional shape of the guide bar 3.

[0033] The variable cross-section region 232 is enclosed by a second inner surface 242 extending in a direction inclined relative to the axial direction (e.g. Figure 14 As shown, the angle between the extension direction of the second inner surface 242 and the axial direction is... (represented by) one end of the second inner surface 242 is smoothly connected to the first inner surface 241, and the other end intersects with the second plane 22 of the end ring 2 to form a second opening 252, so that the equal cross-section region 231 and the variable cross-section region 232 together constitute the second through groove 23 that passes through the end ring.

[0034] As shown in the figure, in the embodiment of this application, the cross-sectional area of ​​the variable cross-section region 232 gradually expands from the end where the second inner surface 242 connects to the first inner surface 241 towards the second plane 22, that is, the second inner surface 242 gradually diffuses from the inside of the end ring 2 towards the second plane 22, such that... Figure 11 As shown in the left-middle figure, the area of ​​the second opening 252 is larger than the area of ​​the first opening 251. Correspondingly, when the radial distances are equal, as... Figure 9 As shown, the width of the second opening Width greater than the first opening .

[0035] Understandably, although Figure 5 , Figure 7 The rotor core 1 and end ring 2 shown in the figure have their first through slot 13 and second through slot 23 configured to open towards the inner wall. However, the first through slot 13 and second through slot 23 can also be configured to only pass through axially and not open in the radial direction, that is, they can be like... Figure 11 As shown in the middle right figure, the first opening 251' and the second opening 252' of the end ring 2 are both closed. In this case, the first inner surface and the second inner surface 242' of the second through groove remain continuous.

[0036] Without loss of generality, The axial height of the constant cross-sectional region 231 of the second through groove 23 is indicated by... Let represent the axial height of the variable cross-section region 232 of the second through groove 23. .

[0037] In some specific embodiments, the end ring 2 is preferably made of a metal material that is easy to conduct electricity, such as aluminum or copper, and can be made by casting, forging, sheet metal cutting or CNC machining.

[0038] c. Structure of guide bar 3 The conductor strip 3 is made of the same material as the end ring 2, such as aluminum, copper, or other easily conductive metals. Figure 10 As shown, the guide bar 3 has a guide bar body 31 extending along the axial direction. The cross-section of the guide bar body 31 is equal everywhere, and its shape matches the equal cross-section region 231 in the first through slot 13 on the rotor core 1 and the second through slot 23 on the end ring 2.

[0039] Without loss of generality, The axial height of the guide bar 3 is indicated. In the embodiments of this application, the axial height of the guide bar 3 is greater than the axial height of the rotor core 1, but less than the sum of the axial height of the rotor core 1 and the axial heights of the two end rings 2, that is: .

[0040] In some preferred embodiments, as shown in the figure, the side of the guide bar 3 facing the axis is configured to have a protrusion 32 that matches the opening 131 of the first through groove 13 on the inner wall of the rotor core 1 and the opening of the second through groove 23 on the inner wall of the end ring 2. During assembly, the protrusion 32 can be embedded into the opening 131 on the inner wall of the rotor core 1. Through slight deformation of the opening, the guide bar 3 can slide smoothly in the first through groove 13 of the rotor core 1.

[0041] d. Awaiting welding Before performing the welding in Operation Two, the rotor core 1, two end rings 2, and several guide bars 3 are first assembled into a state to be welded by Operation One. The number of guide bars 3 used for assembly is the same as the number of first through slots 13 on the rotor core 1 and the number of second through slots 23 on the end rings 2.

[0042] Figure 12 The exploded view schematically illustrates the assembly process of the rotor core 1, two end rings 2, and several guide bars 3 in some specific embodiments. As shown in the figure, each guide bar 3 passes through the first through slot 13 on the rotor core 1 in a one-to-one correspondence. The two ends of the guide bar 3 protrude from the two end faces of the rotor core 1, respectively. The two end rings 2 are respectively positioned on the two end faces of the rotor core 1, and the first plane 21 of each end ring 2 contacts the end face of the rotor core 1. The equal cross-sectional area 231 of the second through slot 23 on the end ring 2 is aligned with each of the first through slots 13 on the rotor core 1, so that the two ends of each guide bar 3 extend into each of the second through slots 23 on the two end rings 2.

[0043] After assembly, each guide bar 3, in a state awaiting welding, has its two end faces 33 located inside the second through grooves 23 of the two end rings 2. Clearly, as described above, due to... Therefore, as long as the length of the guide bar 3 protruding from both ends of the rotor core 1 is equal during the assembly process, it can be ensured that the end face 33 of the guide bar 3 does not protrude beyond the second plane 22 of either of the two end rings 2.

[0044] Figure 13 The diagram illustrates the positional relationship of the rotor core 1, two end rings 2, and several guide bars 3 after assembly and before welding in some preferred embodiments, with a magnified view of circle E. As shown, preferably, the axial height of the guide bars 3 can be... Set to with (That is, the axial height of the first through groove 13 is superimposed with twice the axial height of the equal cross-section region 231 of the second through groove 23) are equal, and after assembly, the end face 33 of the guide bar 3 is located at the connection between the equal cross-section region 231 and the variable cross-section region 232 in the second through groove 23. In this state, the end face 33 of each guide bar 3 and the second inner surface 242 of the variable cross-section region 232 of each second through groove 23 will form a beveled groove that gradually expands from the inside of the second end ring 2 to the second plane 22.

[0045] Understandably, regarding " and The terms "equal" and "the end face 33 of the guide bar 3 is located at the connection between the equal cross-section region 231 and the variable cross-section region 232" should be interpreted broadly. This means that it is permissible for the end face 33 of the guide bar 3 to not be precisely located at the connection between the equal cross-section region 231 and the variable cross-section region 232 of the second through groove 23 due to process tolerances and errors in the assembly process (rather than intentional settings). Therefore, in some embodiments, the groove formed by the end face 33 of the guide bar 3 and the inner surface of the second through groove 23 may also include a portion of the equal cross-section region.

[0046] <Welding Operation> After assembling the rotor core 1, end ring 2, and guide bar 3 into the welding state, the welding process can begin. During the second operation, the end ring 2 and guide bar 3 will be firmly connected by welding wire to form a cage winding through which induced current flows. In the embodiments of this application, the preferred method of welding is to melt the welding wire (the welding wire is made of the same material as the guide bar 3 and end ring 2, such as aluminum or copper) by argon arc welding and fill it into the beveled groove formed by the end face 33 of the guide bar 3 and the inner surface of the second through groove 23.

[0047] Obviously, since the opening direction of the beveled groove for performing the fusion welding operation is towards the second plane 22 of the end ring 2, each end ring 2 needs to have its second plane 22 higher than the first plane 21 during the fusion welding process. That is, the second plane 22 of the end ring 2 in the fusion welding state is set upward. At this time, the second opening 252 of each second through groove 23 on the end ring 2 is higher than the first opening 251. The grooves formed by the end face 33 of the guide bar 3 and the inner surface of the second through groove 23 on the end ring 2 are obviously in a state of gradually increasing upward opening, so that the fusion welding operation can be performed in each groove.

[0048] Figures 14 to 17 Using a partial sectioning method (the sectioning line is) Figure 8 The EE lines in the diagram show the state of the second through groove 23 of an end ring 2 before the guide bar 3 is assembled, the state before welding after the guide bar 3 is assembled, the state at a certain moment during the welding process, and the state when the welding operation is completed.

[0049] Such as 14 and Figure 15 As shown, before welding begins, the surfaces of the end ring 2 and the guide bar 3 have a certain thickness of metal oxide layer. Although the metal oxide layer can be removed before assembly, as analyzed in the background art, the oxide layer is generated very quickly. Therefore, even if the treatment is carried out before assembly, it is still difficult to avoid the reappearance of metal oxide layer on the surface of the guide bar 3 and the inner surface of the second through groove 23 in the welding state after assembly.

[0050] Continue to refer to Figure 16 and Figure 17 During the argon arc welding process, the welding wire is heated to a molten state and fills the beveled groove formed by the end face 33 of the guide bar 3 and the inner surface of the second through groove 23. At the same time, at the fusion welding site, the heat of the arc will cause the guide bar 3 and the end ring 2 below the oxide layer to also reach a molten state (for example, the melting point of aluminum is around 660°C). Due to the welding power source (AC reverse polarity half-wave or DC reverse polarity), the workpiece (aluminum, copper, etc.) becomes the cathode, and the positive ions generated by the ionization of argon gas ( Under the action of an electric field, the metal oxide layer is bombarded at high speed, causing it to break and fall off from the metal surface and splash, exposing the pure metal layer in a molten state below the oxide layer. This allows the welded part 4 formed by the melting of the welding wire to be in complete and firm contact with the inner surface of the guide bar 3 and the second through groove 23 through the pure metal material.

[0051] These metal oxides that break off and detach from the inner surface of the guide bar 3 and the second through groove 23 will always float above the molten welded part 4. As the welding process proceeds, the beveled groove will eventually be completely filled by the melting of the welding wire, thus completing the welding operation between the guide bar 3 and the end ring 2 in the second through groove 23. The same welding process can be used for the other second through grooves 23 of the end ring 2 to complete the welding between the end ring 2 and each guide bar 3.

[0052] After completing the welding of one end ring 2, the rotor core 1 is reversed so that the second plane 22 of the other unwelded end ring 2 faces upward, and the above welding operation can be continued until all the guide bars 3 and the beveled grooves formed by the inner surface of the second through groove 23 are fused together.

[0053] In some alternative embodiments, after welding is completed, the portion of the welded part 4 that extends beyond the surface of the end ring 2 can be smoothed by grinding or other flattening operations.

[0054] Figure 18 The figure illustrates a cage rotor obtained after performing operation two welding on both end rings 2 in some embodiments. As shown, the cage rotor includes a rotor core 1, two end rings 2, a plurality of guide bars 3, and a welded portion 4, the number of which is twice the number of guide bars 3. The two end rings 2 are respectively positioned on the two end faces of the rotor core 1, and the first plane 21 of each end ring 2 contacts the end face of the rotor core 1. The plurality of guide bars 3 pass through a plurality of first through slots 13 on the rotor core 1 in a one-to-one correspondence, and the end of each guide bar is located inside a second through slot 23 on the end ring 2. The second through slot 23 penetrates the first plane 21 and the second plane 22 of the end ring 2. Furthermore, the opening shape of the second through groove 23 on the first plane 21 matches the cross-sectional shape of the guide bar 3, and the opening area on the second plane 22 is larger than the opening area on the first plane 21; the welding part 4 fills the groove formed by the end face 33 of the guide bar 3 and the inner surface of the second through groove 23, thereby achieving a fixed connection with the end face 33 of the guide bar 3 and the inner surface of the second through groove 23, and there are no metal oxide components at the contact positions of the welding part 4 and the end face 33 of the guide bar 3, and at the contact positions of the welding part 4 and the inner surface of the second through groove 23.

[0055] contrast Figure 3 as well as Figures 14 to 17As can be seen, compared with the existing various cage rotor manufacturing schemes, in this application, the second through groove 23 penetrating the end ring 2 is set as a constant cross-section region 231 plus a variable cross-section region 232. The constant cross-section region 231 is used for positioning during the assembly process of the guide bar 3 and the end ring 2. The inclined second inner surface 242 of the variable cross-section region 232 together with the end face 33 of the guide bar 3 forms a bevel-shaped groove. Since the metal oxide layer of this bevel-shaped groove has no obstruction above it during the fusion welding process, it can be ensured that as the welding proceeds, the welding wire, the guide bar 3 and the pure metal part in the end ring 2 are welded together. Using this method, there are no high-resistance metal oxide components between the welded part 4 and the joint of the guide bar 3 and the end ring 2, thereby forming a good current path between the guide bar -> welded part -> end ring.

[0056] Meanwhile, it can be seen that during the fusion welding process, the partially molten welding wire can penetrate into the gap between the equal cross-section region 231 and the guide bar 3, thereby further strengthening the connection strength between the guide bar 3 and the end ring 2.

[0057] In some preferred embodiments, the total area of ​​the second inner surface 242 constituting the variable cross-section region 232 in the second through groove 23 is greater than or equal to the cross-sectional area of ​​the conductor 3, so as to further improve the current conductivity between the conductor 3, the welded part 4 and the end ring 2.

[0058] In some preferred embodiments, the angle between the second inner surface 242 of the variable cross-section region 232 and the axial direction is... Between 30° and 45°, if If the slope is less than 30°, the slope is too steep, which is not conducive to the peeling of the metal oxide layer during the fusion welding process. If the angle is greater than 45°, the opening will be too large, leading to an unnecessary extension of the welding process.

[0059] In some alternative embodiments, such as Figure 19 As shown, before the welding operation, the welding fixture 5, which is used for fusion welding, can be positioned at the joint between the guide bar 3 and the end ring 2. The main body of the welding fixture 5 is circular, and its outer wall is adapted to the inner wall of the end ring 2. Preferably, the welding fixture 5 is also provided with a handle 51 for moving and positioning operations.

[0060] like Figure 20 As shown, before welding, the welding fixture 5 is moved axially to the inside of the end ring 2 to be welded. Since the guide bar 3 extends out of the opening on the inner wall of the end ring 2 through the protrusion 32, the lower surface of the welding fixture 5 contacts the end face 33 of the guide bar 3, and its outer wall will seal the opening on the inner wall of the end ring 2. In the subsequent fusion welding process, the molten welding wire can be effectively prevented from flowing out of the opening.

[0061] In some preferred embodiments, such as Figure 21 As shown, a third through slot 15 and a fourth through slot 26 can be respectively provided on the rotor core 1 and the end ring 2. The third through slot 15 and the fourth through slot 26 are through slots with equal cross sections, and their shapes and positions are consistent, thereby forming an axial air duct on the cage rotor to facilitate heat dissipation during rotor operation.

[0062] Figure 22 A schematic diagram of an asynchronous motor 600 according to some embodiments of this application is shown. Figure 23 This is a cross-sectional view of the asynchronous motor, as shown below. Figure 22 , Figure 23 As shown, the asynchronous motor 600 includes: a rotor 61, a stator 62, a motor shaft 63, a rotor support 64, and a stator support 65, wherein the rotor 61 is... Figure 18 The cage rotor shown.

[0063] The asynchronous motor 600 adopts an external rotor and internal stator configuration. The rotor 61 is coaxially disposed outside the stator 62 and is fixedly connected to the motor shaft 63 extending along the central axis via a rotor support 64. A portion of the rotor support 64 is constructed as the outer casing sidewall of the entire asynchronous motor 600 to fixally connect the rotor 61, and another portion is constructed as a bottom surface of the asynchronous motor. The motor shaft 63 is fixedly connected to the bottom surface by means of bolts or other methods.

[0064] The stator 62 includes a stator core and windings wound on the stator core. The stator 62 is coaxially disposed between the rotor 61 and the motor shaft 63 via a stator support 65. The lead wires 68 of its windings are used to connect to the power supply (usually through switching equipment such as contactors, relays, circuit breakers, or through a motor controller). A part of the stator support 65 is constructed as another bottom surface of the asynchronous motor 600, and another part extends into the interior of the asynchronous motor 600 to form a bearing housing 66. The outer ring and inner ring of the bearing 67 are fixed to the bearing housing 66 and the motor shaft 63, respectively, thereby realizing a rotatable connection between the motor shaft 63 and the stator support 65.

[0065] It is understood that in other alternative embodiments, the asynchronous motor 600 may also be designed as an inner rotor and outer stator. Those skilled in the art can modify the design based on parameters such as motor power and rotor-stator relationship, without departing from the technical principles of this application. Figure 18 The shape and size of each part of the cage rotor shown are adapted.

[0066] Figure 24 The present application illustrates a fan provided according to some embodiments, such as... Figure 24 As shown, the fan is composed of Figure 22 , Figure 23The asynchronous motor 600 shown is composed of a plurality of axial flow blades 700 arranged circumferentially on the side wall of the housing of the asynchronous motor 600.

[0067] Understandable Figure 24 This is merely an illustrative illustration of one embodiment of a fan that can be composed of an asynchronous motor and blades. In this embodiment, since the sidewall of the asynchronous motor 600 is fixedly connected to the rotor 61, the axial flow blades 700 are also fixedly connected to the rotor 61 and the motor shaft 63, thereby maintaining synchronous rotation with the rotor 61 and the motor shaft 63 during motor operation. Obviously, in other embodiments, those skilled in the art can use other forms of blades and other forms of blades fixedly connected to the rotor 61 and the motor shaft 63 as needed. For example, an inner rotor and outer stator structure can be used, with the motor shaft extending out of the motor housing, and centrifugal blades or axial flow blades fixedly connected to the motor shaft through a corresponding connection structure.

[0068] The specific embodiments of this application have been described in detail above. For those skilled in the art, several improvements and modifications can be made to this application without departing from the principle of this application, and these improvements and modifications also fall within the protection scope of the claims of this application.

Claims

1. A method of manufacturing a caged rotor, characterized by, Includes the following operations: The rotor core, several guide bars, and two end rings are assembled into a welding state. The two end rings are respectively positioned on the two end faces of the rotor core, and the first plane of each end ring contacts the end face of the rotor core. The several guide bars pass through several first through slots on the rotor core one by one, and the end of each guide bar is located inside the second through slot on the end ring. The second through slot penetrates the first plane and the second plane of the end ring. Furthermore, the opening shape of the second through slot on the first plane matches the cross-sectional shape of the guide bar, and the opening area on the second plane is larger than the opening area on the first plane. A fusion welding operation is performed using solder within the groove formed by the end face of the guide bar and the inner surface of the second through groove, wherein the second plane of each end ring is set to be higher than the first plane during the fusion welding process.

2. The method for manufacturing a cage rotor according to claim 1, characterized in that, The second through slot includes a constant cross-section region and a variable cross-section region that are interconnected, wherein, The constant cross-section region is enclosed by a first inner surface extending along the axial direction, and the cross-sectional shape of the constant cross-section region is consistent with the cross-sectional shape of the guide strip; The variable cross-section region is enclosed by a second inner surface extending in a direction inclined relative to the axial direction, and the cross-sectional area of ​​the variable cross-section region gradually increases from the end where the second inner surface connects to the first inner surface toward the second plane.

3. The method for manufacturing a cage rotor according to claim 2, characterized in that, The angle between the extension direction of the second inner surface and the axial direction is greater than 30° and less than 45°.

4. The method for manufacturing a cage rotor according to claim 2, characterized in that, The total area of ​​the second inner surface is greater than or equal to the cross-sectional area of ​​the guide bar.

5. The method for manufacturing a cage rotor according to claim 2, characterized in that, The axial height of the guide bar is equal to the axial height of the first through groove plus twice the axial height of the equal cross-section region.

6. The method for manufacturing a cage rotor according to claim 2, characterized in that, The first and second through slots are configured to open toward the inner wall, and the side of the guide bar facing the axis is constructed to have a protrusion that matches the opening of the first through slot on the inner wall of the rotor core and the opening of the second through slot on the inner wall of the end ring.

7. The method for manufacturing a cage rotor according to claim 6, characterized in that, It also includes the following steps: Before the welding operation, the welding fixture for the fusion welding operation is positioned at the joint between the guide bar and the end ring. The main body of the welding fixture is circular, and its outer wall is adapted to the inner wall of the end ring.

8. The method for manufacturing a cage rotor according to claim 2, characterized in that, The rotor core is also provided with a through third slot, and the end ring is also provided with a fourth slot. The third and fourth through slots are both through slots with equal cross-sections, and their shapes and positions are consistent.

9. The method for manufacturing a cage rotor according to any one of claims 1 to 8, characterized in that, The end ring and guide bar are made of aluminum or copper.

10. A cage rotor, comprising a rotor core, two end rings, and a plurality of guide bars, characterized in that, It also includes welding sections, which are twice the number of guide bars; Two end rings are respectively positioned on the two end faces of the rotor core, and the first plane of each end ring contacts the end face of the rotor core. A plurality of guide bars pass through a plurality of first through slots on the rotor core in a corresponding manner, and the end of each guide bar is located inside the second through slot on the end ring. The second through slot penetrates the first plane and the second plane of the end ring, and the opening shape of the second through slot on the first plane matches the cross-sectional shape of the guide bar, and the opening area on the second plane is larger than the opening area on the first plane. The welded part is fixedly connected to the end face of the guide bar and the inner surface of the second through groove, and there are no metal oxide components at the positions where the welded part contacts the end face of the guide bar and the positions where the welded part contacts the inner surface of the second through groove.

11. An asynchronous motor, comprising a rotor, a stator, a motor shaft, a rotor support portion, and a stator support portion, wherein the rotor is coaxially fixedly connected to the motor shaft via the rotor support portion, the stator is fixedly connected to the stator support portion, and the motor shaft is rotatably connected to the stator support portion via bearings, characterized in that... The rotor is the cage rotor as described in claim 10.

12. A fan, characterized in that, include: The asynchronous motor as described in claim 11; Several blades are spaced apart circumferentially and are fixedly connected to the rotor and motor shaft of the asynchronous motor.

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