Rotor assembly, motor and electrical equipment

Abstract

The utility model discloses a rotor assembly, motor and electrical equipment, the rotor assembly comprises a rotor iron core, a plurality of permanent magnets and a plastic package body, the rotor iron core comprises an inner iron core and a plurality of iron core units, the plurality of iron core units are connected with the inner iron core and are arranged at intervals along the direction surrounding the inner iron core, a mounting groove is defined between two adjacent iron core units, and the plastic package body is arranged in the mounting groove. The inner iron core is provided with protrusions and grooves located between every two adjacent iron core units, the protrusions and the grooves are sequentially arranged in the circumferential direction of the inner iron core, and the grooves penetrate through the two end faces of the inner iron core in the axial direction of the rotor iron core. The permanent magnets are correspondingly mounted in the mounting grooves, and the ends, close to the inner iron core, of the permanent magnets abut against the protrusions; the plastic package body wraps the rotor iron core and the plurality of permanent magnets, and partial structure of the plastic package body is filled in the groove; in the radial direction of the rotor core, the minimum depth of the grooves is D, and D is larger than or equal to 1 mm and smaller than or equal to 3 mm. The rotor assembly is high in structural strength and can meet the requirement of high-speed rotation.

Description

Technical Field

[0001] This utility model relates to the field of motor technology, and in particular to a rotor assembly, motor and electrical equipment. Background Technology

[0002] For embedded rotor motors, there is a space filled with plastic (i.e., part of the encapsulated structure) between the permanent magnet and the inner iron core in the radial direction of the rotor. In related technologies, the weld lines of the encapsulated structure in existing rotor structures converge near the inner iron core. When the rotor rotates at high speed, the plastic between the permanent magnet and the inner iron core will crack, and the cracks tend to expand from the inside to the outside, causing the crack range to expand, reducing the structural strength of the rotor, affecting the performance of the motor, and posing safety hazards. Utility Model Content

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a rotor assembly with high structural strength that can meet the requirements of high-speed rotation.

[0004] This utility model also provides a motor and electrical equipment having the above-mentioned rotor assembly.

[0005] A rotor assembly according to a first aspect of the present invention includes a rotor core, comprising an inner core and a plurality of core units. The plurality of core units are connected to the inner core and arranged at intervals along a direction surrounding the inner core. A mounting groove is defined between two adjacent core units. The inner core has a protrusion and a groove located between two adjacent core units. The protrusion and the groove are arranged sequentially along the circumference of the inner core, and the groove penetrates through two end faces of the inner core along the axial direction of the rotor core. A plurality of permanent magnets are respectively mounted in the plurality of mounting grooves, with one end of the permanent magnet near the inner core abutting against the protrusion. A plastic encapsulation body covers the rotor core and the plurality of permanent magnets, and a portion of the structure of the plastic encapsulation body fills the groove. The minimum depth of the groove along the radial direction of the rotor core is D, satisfying: 1mm ≤ D ≤ 3mm.

[0006] The rotor assembly according to the first aspect of this utility model has at least the following beneficial effects: By ensuring that the minimum radial depth D of the groove along the rotor core satisfies 1mm≤D≤3mm, the minimum radial depth of the groove along the rotor core is relatively large while maintaining the structural strength of the inner core. During injection molding of the encapsulation, this facilitates an increase in the flow rate of molten plastic through the groove, causing the molten plastic to converge near the outer side of the rotor assembly. The weld line of the encapsulation is located near the outer side of the rotor assembly, i.e., away from the inner core. When the rotor assembly rotates at high speed, the risk of structural cracking on the side of the encapsulation near the inner core is effectively reduced. Even if cracking occurs, the crack range is effectively minimized, thereby improving the structural strength of the encapsulation and consequently improving the structural strength of the rotor assembly, meeting the requirements of high-speed rotation, and enhancing safety.

[0007] According to some embodiments of the present invention, two grooves are provided between each two adjacent core units, the two grooves being a first groove and a second groove, respectively, and the first groove and the second groove being located on both sides of the protrusion along the circumferential direction.

[0008] According to some embodiments of the present invention, the protrusion has a center line that intersects with and is perpendicular to the central axis of the rotor core, and the first groove and the second groove are symmetrically arranged about the center line.

[0009] According to some embodiments of the present invention, the minimum distance between the two groove walls of the first groove arranged opposite each other along the circumference is W1, the minimum distance between the two groove walls of the second groove arranged opposite each other along the circumference is W2, and the maximum distance between the two wall surfaces of the permanent magnet that are opposite each other along the circumference is W3, satisfying: 0.5≤(W1+W2) / W3≤0.8.

[0010] According to some embodiments of the present invention, the distance between two opposing walls along the circumferential direction of the protrusion decreases radially from the inside to the outside.

[0011] According to some embodiments of the present invention, the end of the protrusion that is away from the central axis of the rotor core is configured as a tip.

[0012] According to some embodiments of the present invention, the core unit is provided with a first material passage hole, which penetrates the two end faces of the core unit along the axial direction and is located near the outer end of the core unit along the radial direction. The inner diameter d of the first material passage hole satisfies: 2mm≤d≤5mm.

[0013] According to some embodiments of the present invention, the core unit is further provided with a second material passage hole, the second material passage hole being located on the side of the first material passage hole near the inner end of the core unit, the second material passage hole penetrating through the two end faces of the core unit along the axial direction, and the inner diameter of the second material passage hole being smaller than the inner diameter of the first material passage hole.

[0014] The motor according to a second aspect embodiment of the present invention includes the rotor assembly of the first aspect embodiment of the present invention.

[0015] The motor according to the second aspect of the present invention has at least the following beneficial effects: Because the motor uses the aforementioned rotor assembly, by ensuring that the minimum radial depth D of the groove along the rotor core satisfies 1mm≤D≤3mm, the minimum radial depth of the groove along the rotor core is relatively large while maintaining the structural strength of the inner core. During injection molding of the encapsulation, this facilitates an increase in the flow rate of molten plastic through the groove, causing the molten plastic to converge near the outer side of the rotor assembly. The weld line of the encapsulation is located near the outer side of the rotor assembly, i.e., away from the inner core. When the rotor assembly rotates at high speed, the risk of structural cracking on the side of the encapsulation near the inner core is effectively reduced. Even if cracking occurs, the crack range can be effectively reduced, thereby improving the structural strength of the encapsulation, which in turn improves the structural strength of the rotor assembly, meeting the requirements of high-speed rotation and enhancing safety.

[0016] The electrical equipment according to the third aspect of the present invention includes the motor according to the second aspect of the present invention.

[0017] The electrical device according to the third aspect embodiment of this utility model has at least the following beneficial effects: Because the electrical device uses the aforementioned motor, by ensuring that the minimum radial depth D of the groove along the rotor core satisfies 1mm≤D≤3mm, the minimum radial depth of the groove along the rotor core is relatively large while maintaining the structural strength of the inner core. During injection molding of the encapsulation, this facilitates an increase in the flow rate of molten plastic through the groove, causing the molten plastic to converge near the outer side of the rotor assembly. The weld line of the encapsulation is located near the outer side of the rotor assembly, i.e., away from the inner core. When the rotor assembly rotates at high speed, the risk of structural cracking on the side of the encapsulation near the inner core can be effectively reduced. Even if cracking occurs, the crack range can be effectively reduced, thereby improving the structural strength of the encapsulation, which in turn improves the structural strength of the rotor assembly, meeting the requirements of high-speed rotation and enhancing safety.

[0018] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0020] Figure 1 This is a schematic diagram of the rotor assembly in an embodiment of the present invention;

[0021] Figure 2 This is an axial sectional view of the rotor assembly in an embodiment of this utility model;

[0022] Figure 3 This is an axial sectional view of the rotor core in an embodiment of this utility model;

[0023] Figure 4 yes Figure 3 Enlarged view of point A in the image;

[0024] Figure 5 This is a schematic diagram of the structure of the rotor core and multiple permanent magnets assembled in an embodiment of this utility model;

[0025] Figure 6 This is a schematic diagram of the structure of the encapsulation body in an embodiment of this utility model.

[0026] Reference numerals:

[0027] Rotor core 100; inner core 110; protrusion 111; first groove 112; second groove 113; core unit 120; first material passage hole 121; second material passage hole 122; limiting part 123; mounting groove 130;

[0028] Permanent magnet 200;

[0029] 300g of encapsulated body. Detailed Implementation

[0030] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0031] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0032] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. If "first" or "second" is used in the description, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0033] In the description of this utility model, unless otherwise explicitly defined, terms such as setting, installing, connecting, assembling, and cooperating should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0034] Reference Figures 1 to 6 As shown, the first aspect of this utility model provides a rotor assembly applied in the motor of an electrical device, such as a washing machine, dryer, or dishwasher. Typically, the motor also includes a stator assembly, and the rotor assembly is rotatably disposed within the inner hole of the stator assembly and is capable of rotating relative to the stator assembly.

[0035] The following section uses the motor in a washing machine as an example to describe the specific structure of the motor rotor assembly in detail. Of course, the rotor assembly of this embodiment is also applicable to the motors of other electrical appliances such as dryers and dishwashers.

[0036] Reference Figure 1 and Figure 2 As shown, it can be understood that the rotor assembly includes a rotor core 100, multiple permanent magnets 200, and a plastic encapsulation 300.

[0037] The direction of the rotation axis of the rotor assembly is defined as the axial direction of the rotor assembly. The direction around the rotation axis of the rotor assembly is the circumferential direction. The direction perpendicular to the rotation axis of the rotor assembly and pointing from the rotation axis to the outer periphery of the rotor assembly, and its reverse direction, are defined as the radial direction of the rotor assembly. Along the radial direction of the rotor assembly, the side closer to the rotation axis of the rotor assembly is called the inner side, and the side farther away from the rotation axis of the rotor assembly is called the outer side.

[0038] Reference Figure 3As shown, the rotor core 100 includes an inner core 110 and multiple core units 120. The inner core 110 is generally annular, and a through hole for the rotating shaft to pass through is provided in the middle of the inner core 110. Generally, the inner core 110 and the rotating shaft are interference-fitted to achieve connection. The core units 120 are generally fan-shaped, and multiple core units 120 are connected to the inner core 110. The smaller end of the core unit 120 is closer to the inner core 110 than the larger end. Furthermore, the multiple core units 120 are arranged at equal intervals along the direction surrounding the inner core 110, which is the circumferential direction of the inner core 110, and the circumferential direction of the inner core 110 is the circumferential direction of the rotor assembly.

[0039] It is understood that the core unit 120 and the inner core 110 can be a single-piece molded structure. Alternatively, the core unit 120 and the inner core 110 can be detachably connected, for example, by a dovetail structure or a T-shaped structure. In this embodiment, multiple core units 120 and inner cores 110 are integrally molded, which facilitates production, reduces assembly processes, improves production efficiency, and makes the overall structure of the rotor core 100 more stable and stronger.

[0040] Reference Figure 3 As shown, it can be understood that a mounting slot 130 is defined between two adjacent core units 120, and the number of mounting slots 130 is equal to the number of core units 120. In this embodiment, the number of core units 120 is ten, and therefore the number of mounting slots 130 is also ten.

[0041] Reference Figure 2 and Figure 3 As shown, it can be understood that multiple permanent magnets 200 are installed in multiple mounting slots 130. That is, the permanent magnets 200 are located between two adjacent core units 120, and the multiple permanent magnets 200 and multiple core units 120 are arranged alternately along the circumference of the rotor assembly. In this example, the number of permanent magnets 200 is equal to the number of mounting slots 130, that is, multiple permanent magnets 200 correspond one-to-one with multiple mounting slots 130, and each mounting slot 130 accommodates one permanent magnet 200.

[0042] In other embodiments, the number of core units 120, mounting slots 130, and permanent magnets 200 may each be eight, twelve, fourteen, or more.

[0043] Reference Figure 3 and Figure 4As shown, the inner core 110 is provided with protrusions 111 and grooves. Specifically, protrusions 111 and grooves are provided on the outer peripheral wall of the inner core 110, with each pair of adjacent core units 120 having a protrusion 111 and a groove. For any two adjacent core units 120, the protrusion 111 protrudes outward toward the mounting groove 130 along the radial direction of the rotor assembly, and the groove is recessed inward relative to the protrusion 111 along the radial direction of the rotor assembly. The protrusions 111 and grooves are arranged sequentially in the circumferential direction of the inner core 110. The groove penetrates two opposite end faces of the inner core 110 along the axial direction of the rotor assembly.

[0044] Reference Figure 2 and Figure 5 As shown, it can be understood that the permanent magnet 200 is installed in the mounting groove 130, and the wall surface of the permanent magnet 200 near the inner iron core 110 abuts against the protrusion 111. That is, the groove is located between the permanent magnet 200 and the inner iron core 110. Generally, the outer end of the iron core unit 120 is also provided with two limiting parts 123. The two limiting parts 123 are respectively located on opposite sides of the iron core unit 120 along the circumference of the rotor assembly, and the limiting parts 123 protrude towards the mounting groove 130 in the circumferential direction of the rotor assembly, that is, the limiting parts 123 are located at the outer end of the mounting groove 130. The two limiting parts 123 on opposite sides of two adjacent iron core units 120 abut against the wall surface of the permanent magnet 200 at the end opposite to the inner iron core 110. Therefore, the protrusion 111, in conjunction with the two limiting parts 123, can position the permanent magnet 200 radially in the rotor assembly, facilitating installation and preventing the permanent magnet 200 from shifting radially along the rotor assembly and becoming loose.

[0045] Reference Figure 1 and Figure 6 As shown, it can be understood that the encapsulation body 300 is made of plastic injection molding. The encapsulation body 300 covers the rotor core 100 and the multiple permanent magnets 200. For example, the encapsulation body 300 covers the two end faces of the rotor core 100 that are opposite to each other along the axial direction of the rotor assembly, the outer wall surface of the limiting portion 123 of the core unit 120, the two end faces of the permanent magnets 200 that are opposite to each other along the axial direction of the rotor assembly, and the wall surface of the permanent magnets 200 facing away from the inner core 110. At the same time, the encapsulation body 300 also fills the gap between the permanent magnets 200 and the rotor core 100 to make the permanent magnets 200 more securely and reliably installed. In this way, the encapsulation body 300 makes the rotor core 100 and the multiple permanent magnets 200 form a whole, which is beneficial to improving the overall structural strength and structural stability of the rotor assembly.

[0046] Reference Figure 2As shown, it can be understood that the encapsulated body 300 also fills the groove, that is, the encapsulated body 300 also covers the wall surface of the permanent magnet 200 near the inner iron core 110 and the outer peripheral wall of the inner iron core 110. On the one hand, this allows the encapsulated body 300 to be embedded in the rotor iron core 100, which is beneficial to improving the bonding strength between the encapsulated body 300 and the rotor iron core 100; on the other hand, when the encapsulated body 300 is injection molded, the groove serves as a flow channel for the molten plastic, allowing the molten plastic to flow from one end of the rotor assembly to the other axially, so that the encapsulated body 300 can cover the two end faces of the rotor iron core 100 that are opposite to each other along the axial direction of the rotor assembly.

[0047] In essence, during injection molding of the encapsulated body 300, the rotor core 100 and multiple permanent magnets 200 are positioned within the mold. Molten plastic is injected into one end of the rotor core 100 along the axial direction of the rotor assembly. The molten plastic flows through the space and grooves on the side of the permanent magnets 200 opposite to the inner core 110 to the other end of the rotor core 100 along the axial direction of the rotor assembly. In other words, the molten plastic can be understood as two streams flowing from one end of the rotor core 100 along the axial direction of the rotor assembly, passing through the inner and outer sides of the rotor core 100 respectively, to the other end of the rotor core 100 along the axial direction of the rotor assembly. The two streams converge at the other end of the rotor core 100. The injection molding process is complete when the molten plastic completely fills the space between the mold and the rotor core 100 and the permanent magnets 200. After the plastic cools, the encapsulated body 300, covering the rotor core 100 and multiple permanent magnets 200, is obtained.

[0048] It is easy to understand that, generally speaking, a weld line is formed at the confluence of two molten plastic fluids, and the connection strength of the encapsulated body 300 at the weld line is lower than that at other locations. During the rotation of the rotor assembly, when the encapsulated body 300 is subjected to stress and cracks, the weld line usually appears first.

[0049] In related technologies, due to the small cross-sectional area of ​​the groove (i.e., the cross-section perpendicular to the rotation axis of the rotor assembly), the flow velocity of molten plastic along the axial direction of the rotor assembly within the groove is low, and less than the flow velocity of molten plastic in the space on the side of the permanent magnet away from the inner iron core. This can also be understood as the flow velocity of molten plastic on the outside of the rotor iron core being greater than that on the inside. The molten plastic on the outside of the rotor iron core reaches the other end of the rotor iron core before the molten plastic on the inside. Therefore, the confluence of the two streams of molten plastic will be closer to the inside of the rotor iron core; that is, the weld line is close to the inside of the rotor iron core. During rotor assembly rotation, if cracking occurs at the weld line, the crack will propagate outwards, resulting in a large crack area. This severely affects the overall structural strength and stability of the encapsulation and rotor assembly, impacting motor performance and posing safety hazards.

[0050] Therefore, referring to Figure 4 As shown, it can be understood that the minimum depth of the groove is defined as D along the radial direction of the rotor core 100 (i.e., the radial direction of the rotor assembly). The minimum depth D of the groove is the minimum distance in the radial direction of the rotor core 100 between the bottom wall of the groove and the end of the protrusion 111 facing away from the rotation axis of the rotor assembly. The bottom wall of the groove is the radially outer wall of the groove facing the rotor assembly, which can also be understood as the outer peripheral wall of the inner core 110. The end of the protrusion 111 facing away from the rotation axis of the rotor assembly can be a tip or a wall surface. When measuring the minimum depth D of the groove, the minimum distance between the bottom wall of the groove and the wall surface of the permanent magnet 200 near the inner core 110 can also be measured.

[0051] Reference Figure 4 As shown, it can be understood that the minimum depth D of the groove satisfies: 1mm ≤ D ≤ 3mm. It is easy to understand that, given a fixed maximum outer diameter of the rotor core 100, a fixed maximum radial dimension of the permanent magnet 200 along the rotor assembly, and a fixed outer diameter of the shaft, a larger minimum groove depth results in a smaller radial thickness of the inner core 110 along the rotor assembly, leading to poorer structural strength and stability. The radial thickness of the inner core 110 along the rotor assembly is the distance between the inner circumferential wall of the inner core 110 and the bottom wall of the groove in the radial direction of the rotor assembly. Ensuring D ≤ 3mm avoids the drawback of an excessively large minimum groove depth leading to an excessively small radial thickness of the inner core 110 along the rotor assembly, thus effectively guaranteeing the structural strength and stability of the inner core 110, and consequently, the structural strength and stability of the rotor core 100.

[0052] Enhancing the minimum depth of the groove (D ≥ 1 mm) increases the cross-sectional area of ​​the groove, which in turn increases the flow rate of molten plastic through the groove during injection molding of the encapsulation body 300. The molten plastic, after exiting the groove, continues to diffuse towards the outside of the rotor core 100, causing the confluence of the two molten plastic streams to be closer to the outside of the rotor core 100. This places the weld line of the encapsulation body 300 closer to the outside of the rotor assembly, meaning the weld line of the encapsulation body 300 is farther from the inner core 110. During high-speed rotation of the rotor assembly, this effectively reduces the risk of structural cracking on the side of the encapsulation body 300 closer to the inner core 110. Even if cracking occurs and the crack propagates outwards, the crack extent can be effectively reduced, thereby improving the structural strength of the encapsulation body 300 and consequently the structural strength of the rotor assembly, meeting the requirements of high-speed rotation and enhancing safety. Examples of suitable values ​​include D = 1 mm, D = 1.5 mm, D = 2 mm, D = 2.5 mm, or D = 3 mm.

[0053] It is understood that the structure located at the inner end of the permanent magnet 200 includes a protrusion 111 and a partially encapsulated body 300 structure filled in the groove. The encapsulated body 300 is non-magnetic, which can effectively reduce the leakage magnetic field at the inner end of the permanent magnet 200, thereby improving the output power of the motor.

[0054] Reference Figure 4 As shown, in this embodiment, each pair of adjacent core units 120 has a protrusion 111 and two grooves, defined as a first groove 112 and a second groove 113. Specifically, the first groove 112 and the second groove 113 are located on both sides of the protrusion 111 along the circumference of the rotor assembly. This increases the channel for the flow of molten plastic at the inner end of the rotor core 100, which helps to keep the weld line of the encapsulation 300 away from the inner core 110, thereby improving the structural strength of the encapsulation 300. In addition, keeping the protrusion 111 away from the two opposite sides of the permanent magnet 200 along the circumference of the rotor assembly helps to reduce the leakage flux at the inner end of the permanent magnet 200.

[0055] Reference Figure 4As shown, in this embodiment, the protrusion 111 is located at the middle position of the permanent magnet 200 along the circumference of the rotor assembly, and the protrusion 111 has a center line that intersects with and is perpendicular to the central axis of the rotor core 100. The first groove 112 and the second groove 113 are symmetrically arranged about the center line of the protrusion 111. Thus, the protrusion 111 abuts against the middle position of the permanent magnet 200 along the circumference of the rotor assembly, balancing the forces on the permanent magnet 200, which helps improve the installation stability of the permanent magnet 200. At the same time, the distance between the protrusion 111 and the two sides of the permanent magnet 200 that are opposite to each other along the circumference of the rotor assembly is relatively large, which helps reduce magnetic leakage. The cross-sectional areas of the first groove 112 and the second groove 113 are the same. The flow rate of the molten plastic in the first groove 112 and the second groove 113 is equal, which is beneficial for the molten plastic to flow synchronously from one end of the rotor core 100 to the other end in the axial direction. This makes the weld line of the encapsulated body 300 far away from the inner core 110 and improves the structural strength of the encapsulated body 300.

[0056] Reference Figure 2 and Figure 4 As shown, it can be understood that the minimum distance between the two groove walls of the first groove 112 arranged opposite each other along the circumference of the rotor assembly is defined as W1, and W1 can be understood as the minimum groove width of the first groove 112; the minimum distance between the two groove walls of the second groove 113 arranged opposite each other along the circumference of the rotor assembly is defined as W2, and W2 can be understood as the minimum groove width of the second groove 113. In this embodiment, the groove widths of the first groove 112 and the second groove 113 both increase from the inside to the outside. That is, the minimum groove width W1 of the first groove 112 is the minimum distance between the intersection of the two groove walls and the bottom wall; similarly, the minimum groove width W2 of the second groove 113 is the minimum distance between the intersection of the two groove walls and the bottom wall.

[0057] Reference Figure 2 and Figure 4 As shown, it can be understood that the maximum distance between two opposing walls of the permanent magnet 200 along the circumference of the rotor assembly is defined as W3, and W3 is the maximum thickness of the permanent magnet 200 along the circumference of the rotor assembly. In other words, W3 can be understood as the maximum thickness of the permanent magnet 200. The minimum groove width W1 of the first groove 112, the minimum groove width W2 of the second groove 113, and the maximum thickness W3 of the permanent magnet 200 satisfy: 0.5 ≤ (W1 + W2) / W3 ≤ 0.8.

[0058] Reference Figure 2 and Figure 4As shown, it can be understood that the maximum distance between the two opposite sidewalls of the protrusion 111 along the circumference of the rotor assembly is defined as W4. W4 can be understood as the maximum thickness of the protrusion 111. Generally speaking, the location of the maximum thickness of the protrusion 111 is located at the end of the protrusion 111 closest to the rotation axis of the rotor assembly. It is easy to understand that, generally speaking, the value of W1+W2+W4 is slightly less than the value of W3.

[0059] Reference Figure 2 and Figure 4 As shown, it can be understood that 0.5 ≤ (W1 + W2) / W3 ≤ 0.8 means that the sum of the minimum groove width of the first groove 112 and the minimum groove width of the second groove 113 is 0.5 to 0.8 times the maximum thickness of the permanent magnet 200. It is easy to understand that, given a fixed value for W3, it can be understood that with a fixed value for W1 + W2 + W4, the smaller the value of W1 + W2, the larger the value of W4; conversely, the larger the value of W1 + W2, the smaller the value of W4. Making (W1 + W2) / W3 ≤ 0.8 avoids the drawback of an excessively small maximum thickness of the protrusion 111 due to an excessively large sum of the minimum groove widths of the first groove 112 and the second groove 113, thus effectively ensuring the structural strength of the protrusion 111, that is, ensuring the overall structural strength of the rotor core 100, to achieve stable positioning of the permanent magnet 200. By ensuring that (W1+W2) / W3≥0.5, the sum of the minimum groove widths of the first groove 112 and the second groove 113 is sufficiently large. Under the premise of satisfying 1mm≤D≤3mm, the sum of the cross-sectional areas of the first groove 112 and the second groove 113 can be increased, thereby increasing the flow rate of the molten plastic in the first groove 112 and the second groove 113, so that the weld line of the encapsulation body 300 is far away from the inner iron core 110, and the structural strength of the encapsulation body 300 is improved.

[0060] Therefore, by ensuring that 0.5 ≤ (W1 + W2) / W3 ≤ 0.8, the sum of the cross-sectional areas of the first groove 112 and the second groove 113 can be increased while maintaining the structural strength of the protrusion 111. This increases the flow velocity of the molten plastic within the first groove 112 and the second groove 113, causing the weld line of the encapsulation 300 to be further away from the inner iron core 110, thereby improving the structural strength of the encapsulation 300. For example, the value of (W1 + W2) / W3 can be 0.5, 0.6, 0.7, or 0.8, etc.

[0061] In other embodiments, each pair of adjacent core units 120 has a groove and a protrusion 111, with the protrusion 111 and the groove arranged sequentially along the circumference of the rotor assembly; this will not be described further here. Alternatively, each pair of adjacent core units 120 may have a groove and two protrusions 111, with the two protrusions 111 located on opposite sides of the groove along the circumference of the rotor assembly; this will not be described further here. This also allows for the positioning of the permanent magnet 200 via the protrusions 111, and enables the encapsulated body 300 to fill the groove.

[0062] Reference Figure 4 As shown, it can be understood that the thickness of the protrusion 111 decreases radially from the inside out; that is, the closer it is to the permanent magnet 200, the smaller the thickness of the protrusion 111. For example, the cross-section of the protrusion 111 is trapezoidal, and the smaller end of the trapezoid is closer to the permanent magnet 200 than the larger end. In this way, the permanent magnet 200 can be positioned by the protrusion 111, and the space occupied by the protrusion 111 can be reduced, thereby increasing the sum of the cross-sectional areas of the first groove 112 and the second groove 113, increasing the flow rate of the molten plastic in the first groove 112 and the second groove 113, and making the weld line of the encapsulation 300 farther away from the inner iron core 110, thus improving the structural strength of the encapsulation 300.

[0063] In other embodiments, the end of the protrusion 111 facing away from the central axis of the rotor core 100 is configured as a pointed end, i.e., the end of the protrusion 111 facing the permanent magnet 200 is a pointed end, and the cross-section of the protrusion 111 is triangular. Similarly, the permanent magnet 200 can be positioned by the pointed end of the protrusion 111 contacting the permanent magnet 200. At the same time, the space occupied by the protrusion 111 can be further reduced, thereby increasing the sum of the cross-sectional areas of the first groove 112 and the second groove 113, increasing the flow rate of the molten plastic in the first groove 112 and the second groove 113, so that the weld line of the encapsulation 300 is far away from the inner core 110, and improving the structural strength of the encapsulation 300.

[0064] Reference Figure 3As shown, it can be understood that in order to allow molten plastic to flow quickly from one end of the rotor core 100 to the other end for rapid filling, each core unit 120 is provided with a first material passage hole 121. The first material passage hole 121 penetrates two opposite end faces of the core unit 120 along the axial direction of the rotor assembly. The first material passage hole 121 is located near the outer end of the core unit 120. The inner diameter of the first material passage hole 121 is defined as d, satisfying 2mm≤d≤5mm. Making d≥2mm ensures the cross-sectional area of ​​the first material passage hole 121, allowing molten plastic to flow through the first material passage hole 121 and increasing the filling speed; making d≤5mm avoids the inner diameter of the first material passage hole 121 being too large, which would result in an excessive flow rate of molten plastic, thereby preventing the weld line of the encapsulated body 300 from being close to the inner core 110 and effectively improving the structural strength of the encapsulated body 300. Therefore, by ensuring that 2mm≤d≤5mm, the speed of filling the plastic can be increased, while avoiding the weld line of the encapsulated body 300 from being close to the inner iron core 110, thus effectively improving the structural strength of the encapsulated body 300.

[0065] It is understandable that by setting the first feed hole 121, a portion of the structure of the encapsulated body 300 is filled in the first feed hole 121. The portion of the encapsulated body 300 filled in the first feed hole 121 can be connected to the two end plates of the encapsulated body 300 along the axial direction of the rotor assembly, which is beneficial to improving the structural strength of the encapsulated body 300 and enhancing the bonding strength between the encapsulated body 300 and the core unit 120.

[0066] Reference Figure 2 and Figure 3 As shown, each core unit 120 is also provided with a second feed hole 122. The second feed hole 122 is located on the side of the first feed hole 121 near the inner core 110, and the inner diameter of the second feed hole 122 is smaller than the inner diameter of the first feed hole 121. The second feed hole 122 penetrates two end faces of the core unit 120 that are opposite to each other along the axial direction of the rotor assembly. This can further increase the filling speed of the plastic, and the speed of the molten plastic in the second feed hole 122 will not be too high, avoiding the weld line of the encapsulation body 300 from being close to the inner core 110. At the same time, it can further improve the structural strength of the encapsulation body 300 and enhance the bonding strength between the encapsulation body 300 and the core unit 120.

[0067] The motor of the second aspect of this utility model includes the rotor assembly of the first aspect of this utility model. The motor also includes a stator assembly, and the rotor assembly is rotatably disposed in the inner hole of the stator assembly, which will not be described in detail here.

[0068] Since the motor adopts all the technical solutions of the rotor assembly of the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments.

[0069] The electrical device according to the third aspect of this utility model includes the motor according to the second aspect of this utility model. The electrical device here may be a washing machine, dryer, dishwasher, etc., which will not be described in detail here.

[0070] Since the electrical equipment adopts all the technical solutions of the motor in the above embodiments, it has at least all the beneficial effects brought about by the technical solutions in the above embodiments.

[0071] The embodiments of the present utility model have been described in detail above with reference to the accompanying drawings. However, the present utility model is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present utility model.

Claims

1. A rotor assembly, characterized in that, include: The rotor core includes an inner core and multiple core units. The multiple core units are connected to the inner core and are spaced apart along the direction surrounding the inner core. A mounting groove is defined between two adjacent core units. The inner core has a protrusion and a groove located between two adjacent core units. The protrusion and the groove are arranged sequentially along the circumference of the inner core, and the groove passes through the two end faces of the inner core along the axial direction of the rotor core. Multiple permanent magnets are respectively installed in multiple mounting slots, with the end of each permanent magnet near the inner iron core abutting against the protrusion; A plastic encapsulation body covers the rotor core and the plurality of permanent magnets, and a portion of the structure of the plastic encapsulation body fills the groove; Wherein, along the radial direction of the rotor core, the minimum depth of the groove is D, which satisfies: 1mm≤D≤3mm.

2. The rotor assembly according to claim 1, characterized in that: Two grooves are provided between each pair of adjacent core units, the two grooves being a first groove and a second groove, respectively, and the first groove and the second groove being located on both sides of the protrusion along the circumferential direction.

3. The rotor assembly according to claim 2, characterized in that: The protrusion has a center line that intersects with and is perpendicular to the central axis of the rotor core, and the first groove and the second groove are arranged symmetrically about the center line.

4. The rotor assembly according to claim 2 or 3, characterized in that: The minimum distance between the two groove walls of the first groove arranged opposite each other along the circumference is W1, the minimum distance between the two groove walls of the second groove arranged opposite each other along the circumference is W2, and the maximum distance between the two walls of the permanent magnet that are opposite each other along the circumference is W3, satisfying: 0.5≤(W1+W2) / W3≤0.

8.

5. The rotor assembly according to claim 2 or 3, characterized in that: The distance between the two opposing walls along the circumferential direction of the protrusion decreases radially from the inside to the outside.

6. The rotor assembly according to claim 5, characterized in that: The end of the protrusion that is away from the central axis of the rotor core is configured as a tip.

7. The rotor assembly according to claim 1, characterized in that: The core unit is provided with a first material passage hole, which penetrates the two end faces of the core unit along the axial direction. Along the radial direction, the first material passage hole is close to the outer end of the core unit. The inner diameter d of the first material passage hole satisfies: 2mm≤d≤5mm.

8. The rotor assembly according to claim 7, characterized in that: The core unit is also provided with a second material passage hole, which is located on the side of the first material passage hole near the inner end of the core unit. The second material passage hole penetrates through both end faces of the core unit along the axial direction, and the inner diameter of the second material passage hole is smaller than the inner diameter of the first material passage hole.

9. An electric motor, characterized in that, Includes the rotor assembly as described in any one of claims 1 to 8.

10. Electrical equipment, characterized in that, Includes the motor as described in claim 9.

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