Rotor assembly, caged motor and method of manufacturing a motor

Abstract

The application relates to the technical field of motor manufacturing, in particular to a rotor assembly, a cage motor and a motor manufacturing method. The rotor assembly comprises a rotor core, a connecting ring and a bar. The rotor core is provided with rotor slots in penetration. The rotor slots are distributed along the radial direction of the rotor core. The rotor slots comprise starting slots, running slots and connecting bridges connecting the starting slots and the running slots. The distance between the starting slots and the outer circle of the rotor core is smaller than the distance between the running slots and the outer circle of the rotor core. The connecting ring is arranged at the two axial ends of the rotor core. The bars are arranged in the rotor slots of the rotor core in filling mode. The two ends of the bars are connected with the two connecting rings respectively. The rotor assembly can be integrally formed by one-time die casting and is convenient to implement while ensuring the starting characteristics of the cage motor.

Description

Technical Field

[0001] This application relates to the field of electric motor manufacturing technology, and in particular to a rotor assembly, a squirrel-cage motor, and a method for manufacturing the motor. Background Technology

[0002] An electric motor is a device that converts mechanical energy into electrical energy and transforms electrical energy based on the phenomenon of electromagnetic induction. It is a very important piece of equipment in industry, agriculture, transportation, national defense engineering, medical equipment, and daily life. Due to its relatively simple structure and the absence of windings on the rotor, the squirrel-cage motor has advantages such as low maintenance costs and long service life, making it the most widely used type of motor in my country's industry and agriculture.

[0003] Wound-rotor motors can improve starting performance and torque by connecting a resistor in series during startup and disconnecting it during operation, thereby altering the resistance. However, this method is not feasible for squirrel-cage motors due to their structural limitations, which is the crux of their poor starting characteristics. In related technologies, the rotor laminations of single-axle electric up-frequency generators utilize the difference in resistivity by inserting different metal materials into their lamination slots, increasing asynchronous starting torque, reducing slip and torque ripple, and thus improving starting performance. However, due to the similar melting points and differences in thermal expansion coefficients of the two metal materials, they cannot be die-cast in a single process, making implementation difficult. Summary of the Invention

[0004] The purpose of this application is to provide a rotor assembly, a squirrel-cage motor, and a method for manufacturing the motor. The rotor assembly can be die-cast in one step while ensuring the starting characteristics of the squirrel-cage motor, which is convenient to implement.

[0005] Therefore, in a first aspect, embodiments of this application provide a rotor assembly, including: a rotor core, through which rotor slots are disposed, the rotor slots being distributed radially along the rotor core, the rotor slots including a starting slot and a running slot to connect the starting slot and the running slot via a connecting bridge, the distance between the starting slot and the outer circle of the rotor core being less than the distance between the running slot and the outer circle of the rotor core; connecting rings disposed at both ends of the rotor core in the axial direction; and guide bars, filling the rotor slots of the rotor core, the two ends of the guide bars being respectively connected to two connecting rings.

[0006] In one possible implementation, the aspect ratio of the starting slot is g / e, and the aspect ratio of the running slot is h / f, where: 5≤g / e≤h / f≤10.

[0007] In one possible implementation, the starting slot has a first slot bottom adjacent to the central axis of the rotor core and a first slot opening opposite to the first slot bottom; the running slot has a second slot bottom adjacent to the rotor core and a second slot opening opposite to the second slot bottom; and the connecting bridge is adjacent to the first slot bottom and the second slot bottom.

[0008] In one possible implementation, the width of the first slot is less than or equal to the width of the second slot, and the width of the second slot is less than the width of the connecting bridge.

[0009] In one possible implementation, an air groove is provided on the outer periphery of the rotor core, with the two ends of the air groove connected to the two ends of the rotor core along its own axial direction. An included angle α is formed between the air groove and the end face of the rotor core, where 0° < α < 90°.

[0010] In one possible implementation, the rotor core is provided with ventilation holes, the two ends of which are connected to the two ends of the rotor core along its own axial direction.

[0011] In one possible implementation, the air tank is positioned adjacent to the operating tank.

[0012] In one possible implementation, the rotor core includes a plurality of stacked rotor laminations, each of which has a rotor slot.

[0013] Secondly, embodiments of this application provide a squirrel-cage motor, comprising: a housing having a cavity; a stator assembly disposed within the cavity of the housing; a rotating shaft passing through the housing and the stator assembly, the rotating shaft being rotatably connected to the housing via a bearing; and a rotor assembly as described above, disposed within the cavity of the housing and connected to the rotating shaft, an air gap being formed between the rotor assembly and the stator assembly.

[0014] Thirdly, embodiments of this application provide a method for manufacturing a squirrel-cage motor, comprising: providing a housing, a shaft, a stator core, and a rotor core; placing the rotor core in a die-casting mold, injecting liquid metal into the rotor slots of the rotor core, and after the liquid metal solidifies, forming a guide bar, wherein the two ends of the guide bar are die-cast integrally with connecting rings at both ends of the rotor core to form a rotor assembly; winding stator winding coils to form a stator winding, and embedding the stator winding into the stator core to form a stator assembly; assembling the stator assembly, rotor assembly, shaft, and housing to obtain a squirrel-cage motor.

[0015] According to the rotor assembly, squirrel-cage motor, and motor manufacturing method provided in the embodiments of this application, the rotor assembly is configured with rotor slots as starting slots, running slots, and connecting bridges. The distance between the starting slot and the outer circle of the rotor core is smaller than the distance between the running slot and the outer circle of the rotor core. An air gap is formed between the rotor assembly and the stator assembly, which is the hub for energy conversion between the stator and rotor of the motor. The guide bars are filled and disposed in the rotor slots. When the motor starts, the skin effect of the part of the guide bar located in the starting slot is more obvious, which is equivalent to the slot area becoming smaller, the resistance becoming larger, and the starting torque becoming larger, thus enhancing the starting characteristics. When the motor is running normally, the rotor current frequency decreases, the skin effect weakens, the leakage reactance of the rotor decreases, and the guide bars in the rotor slots work together, which is equivalent to the slot area increasing, the resistance becoming smaller, thus enhancing the motor's running characteristics. The guide bars can be made of a single metal material, filled in the rotor slots, and die-cast with connecting rings at both ends, thereby achieving one-time die-casting while ensuring the starting characteristics of the squirrel-cage motor, which is convenient for implementation. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0019] Figure 1 This illustration shows a three-dimensional structural diagram of a rotor assembly provided in an embodiment of this application;

[0020] Figure 2 This illustration shows a three-dimensional structural diagram of a rotor core and conductor bars provided in an embodiment of this application;

[0021] Figure 3 This diagram shows a cross-sectional view of a rotor core and connecting ring according to an embodiment of this application.

[0022] Figure 4 This diagram shows a planar structural schematic of a rotor lamination provided in an embodiment of this application.

[0023] Figure 5 Show Figure 4A partially enlarged structural diagram of point A of the rotor lamination shown;

[0024] Figure 6 This diagram shows a front view of a rotor assembly according to an embodiment of this application.

[0025] Figure 7 This illustration shows a three-dimensional structural diagram of a squirrel-cage motor provided in an embodiment of this application;

[0026] Figure 8 This diagram shows a cross-sectional view of a squirrel-cage motor according to an embodiment of this application.

[0027] Figure 9 This illustration shows a three-dimensional structural diagram of a rotor assembly, stator assembly, shaft, and bearing provided in an embodiment of this application.

[0028] Figure 10 This illustration shows a three-dimensional structural diagram of a rotor assembly, shaft, and bearing provided in an embodiment of this application.

[0029] Figure 11 This is a flowchart illustrating a method for manufacturing a squirrel-cage motor according to an embodiment of this application.

[0030] Explanation of reference numerals in the attached figures:

[0031] 1. Rotor core; 11. Rotor slot; 111. Starting slot; 1111. Bottom of first slot; 1112. Opening of first slot; 112. Running slot; 1121. Bottom of second slot; 1122. Opening of second slot; 113. Connecting bridge; 12. Air slot; 13. Ventilation hole; 14. Rotor laminations;

[0032] 2. Connecting ring; 3. Guide bar; 4. Housing; 5. Stator assembly; 6. Shaft; 7. Bearing; 8. Air gap. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0034] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed.

[0035] For ease of description, spatial relative terms may be used in the text to describe the relative position or movement of one element or feature relative to another element or feature, as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "below," "above," "front," "back," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure. For example, if the device in the figure undergoes a positional flip, orientation change, or change of motion, these directional indications will change accordingly. For instance, an element described as "below other elements or features" or "below other elements or features" will subsequently be oriented "above other elements or features" or "above other elements or features." Therefore, the example term "below" can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions), and the spatial relative descriptors used in the text will be interpreted accordingly.

[0036] In related technologies, the rotor laminations of single-pivot electric frequency-up generators utilize the difference in resistivity of different metal materials inserted into their lamination slots to increase asynchronous starting torque, reduce slip and torque fluctuation, thereby improving starting performance. However, due to the similar melting points and differences in thermal expansion coefficients of the two metal materials, they cannot be die-cast in one step, making implementation quite difficult.

[0037] Figure 1 This illustration shows a three-dimensional structural diagram of a rotor assembly provided in an embodiment of this application; Figure 2 This illustration shows a three-dimensional structural diagram of a rotor core and conductor bars provided in an embodiment of this application;

[0038] Figure 3 This diagram shows a cross-sectional view of a rotor core and connecting ring according to an embodiment of this application. Figure 4 This diagram shows a planar structural schematic of a rotor lamination provided in an embodiment of this application.

[0039] Figure 5 Show Figure 4 A partially enlarged structural diagram of point A of the rotor lamination shown; Figure 6This diagram shows a front view of a rotor assembly according to an embodiment of this application.

[0040] like Figures 1 to 6 As shown in the embodiment of this application, a rotor assembly is provided, including: a rotor core 1, a connecting ring 2, and a guide bar 3.

[0041] The rotor core 1 is provided with a rotor slot 11, which is distributed radially along the rotor core 1. The rotor slot 11 includes a starting slot 111 and a running slot 112, and a connecting bridge 113 connecting the starting slot 111 and the running slot 112. The distance between the starting slot 111 and the outer circle of the rotor core 1 is smaller than the distance between the running slot 112 and the outer circle of the rotor core 1. Multiple rotor slots 11 are provided, and the multiple rotor slots 11 are evenly arranged around the central axis of the rotor core 1.

[0042] The connecting ring 2 is located at both ends of the rotor core 1 along the axial direction.

[0043] The guide bar 3 is filled in the rotor slot 11 of the rotor core 1, and the two ends of the guide bar 3 are respectively connected to two connecting rings 2.

[0044] Specifically, the guide bar 3 in the rotor slot 11 of the rotor core 1 is injected with liquid metal material, and after the liquid metal solidifies, it becomes a metal guide bar 3. The guide bar 3 and the connecting ring 2 use the same metal conductive material. The guide bar 3 and the connecting ring 2 at both ends are die-cast to form a squirrel cage structure. The squirrel cage structure and the rotor core 1 form a solid whole, ensuring the overall robustness of the rotor assembly.

[0045] In this application, the rotor slot 11 is configured as a starting slot 111, a running slot 112, and a connecting bridge 113. The distance between the starting slot 111 and the outer circle of the rotor core 1 is smaller than the distance between the running slot 112 and the outer circle of the rotor core 1. An air gap 8 is formed between the rotor assembly and the stator assembly 5. The air gap 8 is the hub for energy conversion between the motor stator and rotor. The guide bar 3 is filled in the rotor slot 11. When the motor starts, the skin effect of the part of the guide bar 3 located in the starting slot 111 is more obvious, which is equivalent to the slot area becoming smaller, the resistance becoming larger, and the starting torque becoming larger, thus enhancing the starting characteristics. When the motor is running normally, the rotor current frequency decreases, the skin effect weakens, and the leakage reactance of the rotor decreases. The guide bar 3 in the rotor slot 11 works together, which is equivalent to the slot area increasing and the resistance becoming smaller, thus enhancing the running characteristics of the motor. The guide bar 3 can be made of a single metal material and filled in the rotor slot 11 and die-cast with the connecting rings 2 at both ends. Thus, while ensuring the starting characteristics of the squirrel-cage motor, it can meet the requirements of one-time die-casting, which is convenient for implementation.

[0046] When the motor starts, the current distribution inside the conductor bar 3 is uneven. The current density in the conductor gradually increases from the bottom of the slot to the top of the slot, resulting in the "skin effect" where the current is concentrated in the conductor. The intensity of the skin effect depends on the frequency of the rotor current and the size of the slot. The higher the frequency and the deeper the slot, the more obvious the skin effect.

[0047] Therefore, in some embodiments, the aspect ratio of the starting slot 111 is g / e, and the aspect ratio of the running slot 112 is h / f, where: 5≤g / e≤h / f≤10.

[0048] like Figure 5 As shown, in this application, by satisfying the aspect ratio of the starting slot 111 and the aspect ratio of the running slot 112 as follows: 5≤g / e≤h / f≤10, the depth of the starting slot 111 and the running slot 112 is guaranteed, thereby further improving the skin effect during motor startup and enhancing the starting characteristics of the motor.

[0049] In some embodiments, the starting slot 111 has a first slot bottom 1111 adjacent to the central axis of the rotor core 1 and a first slot opening 1112 opposite to the first slot bottom 1111; the running slot 112 has a second slot bottom 1121 adjacent to the rotor core 1 and a second slot opening 1122 opposite to the second slot bottom 1121; and the connecting bridge 113 is adjacent to the first slot bottom 1111 and the second slot bottom 1121.

[0050] In this application, an air gap 8 is formed between the rotor assembly and the stator assembly 5. The air gap 8 is the hub for energy conversion between the stator and rotor of the motor. By setting the connecting bridge 113 near the bottom of the first slot 1111 and the bottom of the second slot 1121, that is, away from the air gap 8, this application is more conducive to enhancing the starting and running characteristics of the motor.

[0051] In some embodiments, the width of the first slot portion 1112 is less than or equal to the width of the second slot portion 1122, and the width of the second slot portion 1122 is less than the width of the connecting bridge 113. The first slot portion 1112 is a groove provided at the end of the starting slot 111, and the second slot portion 1122 is a groove provided at the end of the running slot 112.

[0052] In this application, by making the width of the first slot 1112 and the width of the second slot 1122 smaller than the width of the connecting bridge 113, the skin effect of the guide bar 3 in the first slot 1112 can be further improved, which is equivalent to the slot area becoming smaller, the resistance becoming larger, the starting torque becoming larger, and the starting characteristics being enhanced.

[0053] like Figure 5 As shown, specifically, the width of the connecting bridge 113 is defined as i, the width of the first slot 1112 is c, and the width of the second slot 1122 is d. The three satisfy the dimensional relationship: 0 < c ≤ d < i.

[0054] In addition, the rotor slot 11 is a closed slot, that is, the starting slot 111, the running slot 112 and the connecting bridge 113 are not connected to the outer periphery of the rotor core 1. After die casting, there is no die-cast metal conductive material on the outer circular surface of the rotor core 1. Therefore, it is not necessary to ensure its outer diameter roundness and accuracy through rotor precision machining process, which reduces production operation steps, reduces manufacturing costs and improves motor production efficiency.

[0055] In related technologies, in order to achieve high motor energy efficiency, the air gap 8 between the stator and rotor of the motor is often relatively small during design and theoretical calculation. When the motor is running normally, the stator winding and the cage-type conductor bar 3 will generate a large amount of heat, which will have an adverse effect on the normal operation and life of the motor. Due to the relatively compact internal structure of the motor, airflow cannot be formed inside the motor, resulting in poor heat dissipation.

[0056] like Figure 6 As shown, therefore, in some embodiments, an air groove 12 is provided on the outer periphery of the rotor core 1. The two ends of the air groove 12 are respectively connected to the two ends of the rotor core 1 along its own axial direction. An included angle α is formed between the air groove 12 and the end face of the rotor core 1, wherein 0° < α < 90°. Specifically, the cross-section of the air groove 12 is preferably a semi-circular structure, but it can also be other shapes.

[0057] In this application, the rotor core 1 is formed by stacking multiple rotor laminations 14. The air slot 12 is twisted at a certain angle with the rotor core 1 to form a structure similar to an axial flow fan blade. When the motor is running, it can rotate to drive the heat between the stator and rotor components, forming an axial airflow, which improves the heat dissipation effect and reduces the temperature rise of the motor.

[0058] In addition, the rotor core 1 adopts the air slot 12 skew method, which can effectively weaken the harmonic electromotive force generated by the tooth harmonic magnetic field, solve the additional torque caused by the harmonic magnetic field, and effectively reduce the electromagnetic vibration and noise of the motor.

[0059] Furthermore, the rotor core 1 is provided with ventilation holes 13, and the two ends of the ventilation holes 13 are respectively connected to the two ends of the rotor core 1 along its own axial direction.

[0060] In this application, by providing ventilation holes 13 on the rotor core 1, the axial airflow generated inside the motor can flow through the ventilation holes 13, which can further improve the heat dissipation effect.

[0061] In some embodiments, the air duct 12 is disposed adjacent to the running duct 112.

[0062] In this application, the air trough 12 is located adjacent to the running trough 112. When the motor is running, the conductor 3 cuts the magnetic field lines to generate current. The heat generated by the conductor 3 can be discharged in time through the air trough 12, further improving the heat dissipation effect.

[0063] In some embodiments, the rotor core 1 includes a plurality of stacked rotor laminations 14, each of which has a rotor slot 11.

[0064] In this application, multiple rotor laminations 14 adopt the same structure. When multiple rotor laminations 14 are stacked, they are twisted at a certain angle to realize that the air grooves 12 are spirally arranged along the outer circumference of the rotor core 1, thereby ensuring that the rotor core 1 can generate axial airflow inside the motor through the air grooves 12 when rotating. In addition, the rotor laminations 14 with the same structure are convenient for mass production. The rotor grooves 11 and ventilation holes 13 are also twisted structures. The structure of the guide bar 3 is the same as that of the rotor grooves 11. When the guide bar 3 is cured, it can ensure the stability of the rotor core 1 structure.

[0065] The rotor assembly is configured by setting the rotor slot 11 as a starting slot 111, a running slot 112, and a connecting bridge 113. The distance between the starting slot 111 and the outer circle of the rotor core 1 is smaller than the distance between the running slot 112 and the outer circle of the rotor core 1. An air gap 8 is formed between the rotor assembly and the stator assembly 5. The air gap 8 is the hub for energy conversion between the motor stator and rotor. The guide bar 3 is filled in the rotor slot 11. When the motor starts, the skin effect of the part of the guide bar 3 located in the starting slot 111 is more obvious, which is equivalent to the slot area becoming smaller, the resistance becoming larger, and the starting torque becoming larger, thus enhancing the starting characteristics. When the motor is running normally, the rotor current frequency decreases, the skin effect weakens, and the leakage reactance of the rotor decreases. The guide bar 3 in the rotor slot 11 works together, which is equivalent to the slot area increasing and the resistance becoming smaller, thus enhancing the running characteristics of the motor. The guide bar 3 can be made of a single metal material and filled in the rotor slot 11 and die-cast with the connecting rings 2 at both ends. Thus, while ensuring the starting characteristics of the squirrel-cage motor, it can meet the requirements of one-time die-casting, which is convenient for implementation.

[0066] Figure 7 This illustration shows a three-dimensional structural diagram of a squirrel-cage motor provided in an embodiment of this application; Figure 8 This diagram shows a cross-sectional view of a squirrel-cage motor according to an embodiment of this application. Figure 9 This illustration shows a three-dimensional structural diagram of a rotor assembly, stator assembly, shaft, and bearing provided in an embodiment of this application. Figure 10 This diagram illustrates a three-dimensional structure of a rotor assembly, shaft, and bearing provided in an embodiment of this application.

[0067] like Figures 7 to 10As shown, this application provides a squirrel-cage motor, including: a housing 4 having a cavity; a stator assembly 5 disposed in the cavity of the housing 4; a rotating shaft 6 passing through the housing 4 and the stator assembly 5, the rotating shaft 6 being rotatably connected to the housing 4 via a bearing 7; and a rotor assembly as described above, disposed in the cavity of the housing 4 and connected to the rotating shaft 6, an air gap 8 being formed between the rotor assembly and the stator assembly 5.

[0068] In this application, the stator assembly 5 is fixedly installed inside the housing 4, and the rotor assembly is rotatably installed inside the housing 4 via the rotating shaft 6. An alternating magnetic field is generated inside the housing 4 by the stator assembly 5. The conductor bars 3 of the rotor assembly cut the magnetic field lines to generate current. Under the action of the current, the rotor assembly is driven to rotate. The rotational power is output through the rotating shaft 6. This application improves the starting characteristics of the motor by setting a rotor slot 11 with a specific structure on the rotor core 1 of the rotor assembly, injecting conductive metal of the same material into the rotor slot 11 to form conductor bars 3, and die-casting the conductor bars 3 and the connecting rings 2 at both ends. This eliminates the need to insert conductive metal of different materials into the rotor slot 11, making it convenient to manufacture and implement.

[0069] Figure 11 This is a flowchart illustrating a method for manufacturing a squirrel-cage motor according to an embodiment of this application.

[0070] like Figure 11 As shown in the figure, this application provides a method for manufacturing a squirrel-cage motor, including: providing a housing 4, a shaft 6, a stator core, and a rotor core 1; placing the rotor core 1 in a die-casting mold, injecting liquid metal into the rotor slot 11 of the rotor core 1, and after the liquid metal solidifies, forming a guide bar 3, with both ends of the guide bar 3 being die-cast integrally with the connecting rings 2 at both ends of the rotor core 1 to form a rotor assembly; winding stator winding coils to form a stator winding, and embedding the stator winding into the stator core to form a stator assembly 5; assembling the stator assembly 5, the rotor assembly, the shaft 6, and the housing 4 to obtain a squirrel-cage motor.

[0071] S1. Provide housing 4, rotating shaft 6, stator core and rotor core 1;

[0072] S2. Place the rotor core 1 in the die-casting mold and inject liquid metal into the rotor slot 11 of the rotor core 1. After the liquid metal solidifies, it forms a guide bar 3. The two ends of the guide bar 3 are die-cast integrally with the connecting rings 2 at both ends of the rotor core 1 to form a rotor assembly.

[0073] S3. Wind the stator winding coil to form a stator winding, and embed the stator winding into the stator core to form stator assembly 5;

[0074] S4. Assemble the stator assembly 5, rotor assembly, shaft 6 and housing 4 to obtain a squirrel-cage motor.

[0075] In S2, the liquid metal injected into the rotor core 1 is preferably pure aluminum or copper.

[0076] In S3, the stator winding coil material is preferably enameled copper wire or enameled aluminum wire, and the stator winding is embedded into the stator core using a special embedding device.

[0077] The method for manufacturing a squirrel-cage motor provided in this application can improve the starting and running characteristics of the motor, and the manufacturing method is simple and improves production efficiency.

[0078] It should be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “described” as used herein may also include the plural forms. The terms “comprising,” “including,” “containing,” and “having” are inclusive and therefore indicate the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not construed as requiring them to be performed in a particular order described or illustrated unless the order of performance is explicitly indicated. It should also be understood that additional or alternative steps may be used.

[0079] Although terms such as first, second, third, etc., may be used in this document to describe multiple elements, components, regions, layers, and / or segments, these elements, components, regions, layers, and / or segments should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or segment from another. Unless the context clearly indicates otherwise, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence. Therefore, the first element, component, region, layer, or segment discussed below may be referred to as the second element, component, region, layer, or segment without departing from the teachings of the exemplary embodiments.

[0080] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A rotor assembly, characterized in that, include: A rotor core (1) is provided with a rotor slot (11) through it. The rotor slot (11) is distributed radially along the rotor core (1). The rotor slot (11) includes a starting slot (111) and a running slot (112) to connect the starting slot (111) and the running slot (112) via a connecting bridge (113). The distance between the starting slot (111) and the outer circle of the rotor core (1) is smaller than the distance between the running slot (112) and the outer circle of the rotor core (1). Connecting rings (2) are disposed at both ends of the rotor core (1) along its axial direction; and The guide bar (3) is filled in the rotor slot (11) of the rotor core (1), and the two ends of the guide bar (3) are respectively connected to the two connecting rings (2); The aspect ratio of the starting slot (111) is g / e, and the aspect ratio of the running slot (112) is h / f, wherein: 5≤g / e≤h / f≤10.

2. The rotor assembly according to claim 1, characterized in that, The starting slot (111) has a first slot bottom (1111) adjacent to the central axis of the rotor core (1) and a first slot opening (1112) opposite to the first slot bottom (1111); the running slot (112) has a second slot bottom (1121) adjacent to the rotor core (1) and a second slot opening (1122) opposite to the second slot bottom (1121). The connecting bridge (113) is adjacent to the bottom of the first groove (1111) and the bottom of the second groove (1121).

3. The rotor assembly according to claim 2, characterized in that, The width of the first slot (1112) is less than or equal to the width of the second slot (1122), and the width of the second slot (1122) is less than the width of the connecting bridge (113).

4. The rotor assembly according to claim 1, characterized in that, An air groove (12) is provided on the outer periphery of the rotor core (1). The two ends of the air groove (12) are respectively connected to the two ends of the rotor core (1) along its own axial direction. An angle α is formed between the air groove (12) and the end face of the rotor core (1), where 0° < α < 90°.

5. The rotor assembly according to claim 4, characterized in that, The rotor core (1) is provided with ventilation holes (13), and the two ends of the ventilation holes (13) are respectively connected to the two ends of the rotor core (1) along its own axial direction.

6. The rotor assembly according to claim 4, characterized in that, The air trough (12) is located adjacent to the running trough (112).

7. The rotor assembly according to any one of claims 1-6, characterized in that, The rotor core (1) includes a plurality of stacked rotor laminations (14), and the rotor laminations (14) are respectively provided with rotor slots (11).

8. A squirrel-cage motor, characterized in that, include: The shell (4) has a cavity; The stator assembly (5) is disposed within the cavity of the housing (4); A rotating shaft (6) extends through the housing (4) and the stator assembly (5), the rotating shaft (6) being rotatably connected to the housing (4) via a bearing (7); and The rotor assembly as described in any one of claims 1 to 7 is disposed within the cavity of the housing (4) and connected to the rotating shaft (6), and an air gap (8) is formed between the rotor assembly and the stator assembly (5).

9. A method for manufacturing a squirrel-cage motor as described in claim 8, characterized in that, include: Provide housing (4), shaft (6), stator core and rotor core (1); The rotor core (1) is placed in a die-casting mold, and liquid metal is injected into the rotor slot (11) of the rotor core (1). After the liquid metal solidifies, it forms a guide bar (3). The two ends of the guide bar (3) are die-cast integrally with the connecting rings (2) at both ends of the rotor core (1) to form a rotor assembly. The stator winding coil is wound to form a stator winding, and the stator winding is embedded into the stator core to form a stator assembly (5). The stator assembly (5), the rotor assembly, the shaft (6) and the housing (4) are assembled to obtain a squirrel-cage motor.

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