Motor rotor and permanent magnet synchronous motor

Abstract

The utility model provides a motor rotor, and the motor rotor comprises a rotor iron core which comprises an outer iron core located on the outer side in the radial direction and an inner iron core located on the inner side in the radial direction; permanent magnets arranged in the outer core in a circumferential direction; the injection molding part at least partially wraps the rotor iron core in the circumferential direction and covers the end part of the rotor iron core, so that a first end part and a second end part, which are opposite to each other in the axial direction, of the motor rotor are formed; the heat dissipation structure comprises heat dissipation fan bodies formed by injection molding parts in the area of the inner side iron core and heat dissipation channels formed between the heat dissipation fan bodies, and the heat dissipation fan bodies extend in partial sections in the axial direction in a staggered mode, so that the heat dissipation channels extend in the axial direction in a staggered mode. In addition, the utility model also provides a permanent magnet synchronous motor.

Description

Motor rotor and permanent magnet synchronous motor Technical Field

[0001] This disclosure relates to motor rotors and permanent magnet synchronous motors. Background Technology

[0002] In the field of permanent magnet synchronous motors, temperature rise is a common and significant technical challenge. Excessive temperature rise can affect motor performance, lifespan, and even cause malfunctions.

[0003] The causes of temperature rise involve multiple factors, including electrical, mechanical, and thermodynamic aspects. For example, the causes of temperature rise include:

[0004] Electrical losses can be divided into copper losses and iron losses. Copper losses are generated when the current in the stator windings passes through the resistor and produces heat; iron losses are generated when the rotor core and stator core generate eddy current losses and hysteresis losses in an alternating magnetic field and produce heat.

[0005] Mechanical losses: poor bearing lubrication or wear can lead to bearing friction; rotor friction with air can cause wind wear; rotor imbalance or misalignment can lead to additional friction and heat generation.

[0006] Poor heat dissipation: Insufficient cooling system or high ambient temperature.

[0007] If the motor temperature rises too drastically, the possible consequences include the following:

[0008] High temperatures accelerate the aging of insulating materials, reduce their insulation performance, and increase the risk of short circuits or breakdowns.

[0009] Temperature rise leads to increased winding resistance, increased copper losses, and reduced motor efficiency.

[0010] High temperatures may cause thermal expansion of rotor or stator components, leading to mechanical deformation, friction, or vibration;

[0011] Sustained high temperatures can significantly shorten the lifespan of motors and increase maintenance and replacement costs.

[0012] To address the aforementioned temperature rise issue, existing technologies typically employ measures such as optimized design, material upgrades, and improved heat dissipation to mitigate the temperature rise.

[0013] For example, in terms of heat dissipation improvement, existing technologies employ a rotor that uses a guide cone at its end with a fan blade structure on that cone. The interaction between the guide cone and the fan blade structure creates airflow along the rotor's axial direction, thus improving heat dissipation. While this rotor achieves heat dissipation, its internal heat dissipation holes are axial circular holes, resulting in a single airflow path. Furthermore, it relies on the external conical structure to guide the airflow, limiting its heat dissipation performance. Summary of the Invention

[0014] In response to the problems and needs mentioned above, this disclosure proposes a motor rotor and a permanent magnet synchronous motor having said motor rotor, which solves the above problems and brings other technical effects by adopting the following technical features.

[0015] On one hand, this disclosure proposes an electric motor rotor, comprising: a rotor core including an outer core located radially outward and an inner core located radially inward; a permanent magnet arranged circumferentially in the outer core; an injection-molded portion that at least partially covers the rotor core circumferentially and covers the ends of the rotor core to form a first end and a second end of the electric motor rotor facing each other axially; and a heat dissipation structure including a heat dissipation fan formed by the injection-molded portion in a region of the inner core and a heat dissipation channel formed between the heat dissipation fan, wherein the heat dissipation fan extends offset in a portion of the axial direction, thereby causing the heat dissipation channel to extend offset axially.

[0016] According to a preferred embodiment, the heat dissipation channel extends from the first end to the second end, and includes at least a first channel segment and a second channel segment that is axially offset relative to the first channel segment.

[0017] According to a preferred embodiment, the inner iron core includes multiple reinforcing ribs, wherein the injection-molded portion covers the reinforcing ribs, thereby forming the heat dissipation fan body.

[0018] According to the preferred embodiment, the extension line of the reinforcing rib does not pass through the center of the rotor.

[0019] According to a preferred embodiment, the heat dissipation fan body includes at least a first fan body and a second fan body that are offset from each other along the axial direction, wherein the injection molding portion covers the reinforcing rib from the first end to form the first fan body, and the injection molding portion covers the reinforcing rib from the second end to form the second fan body.

[0020] According to the preferred embodiment, the rotor core is constructed in a two-stage configuration.

[0021] According to a preferred embodiment, the rotor core includes a first rotor core with a first reinforcing rib and a second rotor core with a second reinforcing rib, which are axially opposed to each other.

[0022] According to a preferred embodiment, the first fan body includes the first reinforcing rib and an injection-molded portion covering the first reinforcing rib, and the second fan body includes the second reinforcing rib and an injection-molded portion covering the second reinforcing rib.

[0023] According to a preferred embodiment, the first fan body and the second fan body are offset from each other by a staggered angle of 10° to 30°.

[0024] According to the preferred embodiment, the circumferential width of the second sector is less than the minimum circumferential width at the point where the first channel section and the second channel section transition at an offset.

[0025] According to the preferred embodiment, the circumferential width of the first sector is smaller than the circumferential width of the second sector.

[0026] According to a preferred embodiment, the heat dissipation fan body further includes an end fan body located axially outside the first fan body and / or the second fan body.

[0027] According to a preferred embodiment, the end fan body is formed by injection molding.

[0028] According to a preferred embodiment, the cooling fan body is constructed in a centrally symmetrical manner.

[0029] On the other hand, this disclosure also proposes a permanent magnet synchronous motor, which includes a motor stator and a motor rotor as described in any of the preceding items.

[0030] The preferred embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings, so as to facilitate a better understanding of the features and advantages of the present disclosure. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings of the embodiments of this disclosure will be briefly described below. The drawings are merely illustrative of some embodiments of this disclosure and are not intended to limit all embodiments of this disclosure to them.

[0032] Figure 1 schematically shows a perspective view of an electric motor rotor according to one embodiment of the present disclosure;

[0033] Figure 2 schematically shows a perspective view of the rotor core of an electric motor rotor according to one embodiment of the present disclosure;

[0034] Figure 3 schematically shows a top view of the rotor core shown in Figure 2;

[0035] Figure 4 schematically shows a perspective sectional view of the motor rotor shown in Figure 1;

[0036] Figure 5 schematically shows a partial cross-sectional view of the motor rotor shown in Figure 1;

[0037] Figure 6 schematically shows a top view of an electric motor rotor according to one embodiment of the present disclosure;

[0038] Figure 7 schematically shows a partial cross-sectional view obtained along the section line AA shown in Figure 6;

[0039] Figure 8 schematically shows a side view of an electric motor rotor according to one embodiment of the present disclosure;

[0040] Figure 9 schematically shows a partial cross-sectional view obtained along the section line BB shown in Figure 8;

[0041] Figure 10 schematically shows a partial cross-sectional view obtained along the section line CC shown in Figure 8;

[0042] Figure 11 schematically shows a cross-sectional view of a permanent magnet synchronous motor according to the present disclosure; and

[0043] Figure 12 schematically shows a simulation diagram of the internal air duct of an electric motor housing according to one embodiment of the present disclosure. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. The same reference numerals in the drawings represent the same components. It should be noted that the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0045] Compared to the embodiments shown in the accompanying drawings, feasible embodiments within the scope of this disclosure may have fewer components, other components not shown in the drawings, different components, components arranged differently, or components with different connections, etc. Furthermore, two or more components in the drawings may be implemented in a single component, or a single component shown in the drawings may be implemented as multiple separate components.

[0046] The motor rotor 100 disclosed herein may generally include a rotor core 110, a plurality of permanent magnets 120 arranged on the outer periphery of the rotor core 110, and an injection-molded part 130 that penetrates the rotor core 110 and at least partially covers the plurality of permanent magnets 120 to fix the rotor core 110 and the permanent magnets 130 into a whole.

[0047] The rotor core 110 can be formed by stamping and stacking silicon steel sheets. The stamping and stacking method of the silicon steel sheets is known in the prior art and will not be described in detail here.

[0048] The rotor core 110 is generally cylindrical in shape and includes an outer core 111 located radially outward and an inner core 112 located radially inward. Permanent magnets 120 are arranged circumferentially in the outer core 111. Preferably, the permanent magnets 120 are evenly arranged around the outer periphery of the outer core 111, and are arranged with alternating circumferential and radial magnetization.

[0049] Multiple spaced reinforcing ribs 113 are provided in the region of the inner core 112. Here, the extension line of the reinforcing rib 113 does not pass through the center O of the rotor core 110, that is, the reinforcing rib 113 extends radially offset relative to the rotor core 110.

[0050] Preferably, a keyway 114 for connecting the rotor shaft is provided at the center hole of the inner iron core 112.

[0051] The injection molding portion 130 at least partially covers the rotor core 110 circumferentially and covers the ends of the rotor core 110, thereby forming a first end 100a and a second end 100b of the motor rotor 100 that are axially opposed to each other.

[0052] To address the issue of severe temperature rise, the motor rotor 100 also includes a heat dissipation structure. This structure includes a heat dissipation fan 140 formed by an injection molding portion 130 in the region of the inner iron core 112 and a heat dissipation channel 141 formed between the heat dissipation fan 140. The heat dissipation fan 140 extends offset in a portion of its axial direction, thereby causing the heat dissipation channel 141 to extend offset axially. Unlike existing technologies, the heat dissipation fan according to this disclosure is formed by injection molding, utilizing rotor rotation to accelerate airflow within the motor for air cooling. This does not increase rotor costs and reduces the overall motor cost by eliminating the need for a separate fan, effectively reducing temperature rise and avoiding other adverse consequences caused by temperature rise. It should be noted that "offset axially" in this disclosure specifically means that the axial direction is not along a straight line, but rather an angular offset. As shown in Figures 4 and 5, multiple cooling fans 140 are arranged rotationally symmetrically in the region of the inner core 112. A heat dissipation channel 141 is formed between two adjacent cooling fans 140, and the heat dissipation channel 141 extends from the first end 100a of the motor rotor 100 to the second end 100b. Each cooling fan 140 does not extend linearly along the axial direction, but is offset axially in its middle; correspondingly, each heat dissipation channel 141 also does not extend linearly along the axial direction, but is also offset axially in its middle.

[0053] The rotor core 110 shown in Figures 2 and 3 is constructed as a two-stage permanent magnet rotor. Here, the rotor core 110 includes a first rotor core 110a and a second rotor core 110b that are axially opposed to each other. The first rotor core 110a preferably has the same structure as the second rotor core 110b.

[0054] For clarity, the structure of the motor rotor 100 is shown in cross-sectional view with the aid of Figures 8 to 10.

[0055] The first rotor core 110a includes an outer core 111a and an inner core 112a. Multiple reinforcing ribs 113a are provided in the region of the inner core 112a, and a keyway 114a for connecting the rotor shaft can be provided at the central hole of the inner core 112a. Similarly, the second rotor core 110b includes an outer core 111b and an inner core 112b. Multiple reinforcing ribs 113b are provided in the region of the inner core 111b, and a keyway 114b for connecting the rotor shaft can be provided at the central hole of the inner core 112b.

[0056] In the preparation process of the heat dissipation fan body 140, the first rotor core 110a and the second rotor core 110b are first placed in a mold, wherein the first rotor core 110a and the second rotor core 110b are connected to each other, and the keyway 114a of the first rotor core 110a is aligned with the keyway 114b of the second rotor core 110b, and the first rotor core 110a and the second rotor core 110b are opposite to each other, so that the reinforcing rib 113a of the first rotor core 110a and the reinforcing rib 113b of the second rotor core 110b are offset from each other; then, permanent magnets 120 are sequentially inserted into the region of the outer core 111 of the rotor core 100; finally, the rotor core 100 and the permanent magnets 120 are encapsulated into a whole by injection molding using injection molding material.

[0057] Preferably, since the reinforcing ribs of the first rotor core 110a and the second rotor core 110b are offset relative to each other, a heat dissipation fan body 140 extending axially offset will be formed after molding. Here, the heat dissipation fan body 140 includes at least an injection-molded portion 130 and a reinforcing rib 113 covered therewith.

[0058] As shown in Figures 4 to 7, the heat dissipation fan 140 includes a first fan 140a and a second fan 140b. The first fan 140a is composed of a reinforcing rib 113a of a first rotor core 110a and an injection-molded portion 130 covering the reinforcing rib 113a. The second fan 140b is composed of a reinforcing rib 113b of a second rotor core 110b and an injection-molded portion 130 covering the reinforcing rib 113b. The first fan 140a and the second fan 140b are axially offset and connected to each other, so that the heat dissipation channel 141 formed between the heat dissipation fan 140s correspondingly includes a first channel section 141a and a second channel section 141b. The first channel section 141a and the second channel section 141b are axially offset and transitionally connected to each other at a transition section 141c.

[0059] Because the reinforcing ribs of the first rotor core 110a and the second rotor core 110b are offset from each other, the first fan body 140a and the second fan body 140b are also offset axially. Preferably, the first fan body 140a and the second fan body 140b are offset from each other by an offset angle α of 10° to 30°. If the offset angle α is too small or too large, the heat dissipation channel will be too narrow, which is not conducive to airflow. In addition, the offset angle of the reinforcing ribs of the first rotor core 110a and the second rotor core 110b not only helps to form the heat dissipation fan body 140, but the second rotor core 110b can also share the pressure borne by the first rotor core 110a during injection molding, thus playing a supporting role.

[0060] Preferably, the circumferential width of the second fan body 140b is less than the minimum circumferential width at the transition point where the first channel section 141a and the second channel section 141b are offset. In this case, the size of the second fan body 140b ensures the unobstructed flow of the heat dissipation channel; otherwise, the second fan body 140b of the heat dissipation fan body 140 would completely block the heat dissipation channel 141, preventing air from flowing from one end of the motor to the other. Generally, to ensure sufficient space for air to pass through the heat dissipation channel 141, the circumferential width of the second fan body 140b is approximately 0.5 times the minimum circumferential width at the transition section 141c.

[0061] Preferably, the heat dissipation fan 140 further includes an upper end fan 140d located axially outside the first fan 140a and a lower end fan 140e located axially outside the second fan 140b. The upper end fan 140e and the lower end fan 140e are each formed by injection molding 130, wherein the circumferential width of the upper end fan 140d is not greater than the circumferential width of the first fan 140a connected to it, and the circumferential width of the lower end fan 140e is not greater than the circumferential width of the second fan 140b connected to it.

[0062] The heat dissipation channel 141 disclosed herein is jointly composed of a first channel section 141a and a second channel section 141b. In addition to having the heat dissipation effect of a conventional circular hole, the transition connection between the first channel section 141a and the second channel section 141b is misaligned to form a dislocation portion of the heat dissipation fan 140. When the motor rotor rotates, the integrated heat dissipation structure can further improve airflow and has better heat dissipation performance.

[0063] As shown in Figure 11, the permanent magnet synchronous motor 1000 includes the aforementioned motor rotor 100, motor stator 200, and motor housing 300 for accommodating the motor rotor 100 and motor stator 200.

[0064] The motor rotor 100, motor stator 200, and motor shaft are installed in the motor housing 300 to form a permanent magnet synchronous motor 1000. In the prior art motor design, when there is no heat dissipation structure according to the present disclosure, the motor relies solely on an additional fan for air cooling; the rotor fan structure motor further promotes airflow inside the motor through the rotor fan structure. For the permanent magnet synchronous motor 1000 according to this disclosure, heat dissipation is achieved by means of its own heat dissipation structure. When the permanent magnet synchronous motor is working, the motor rotor rotates. The heat dissipation fan 140, composed of the first fan body 140a and the second fan body 140b, promotes the air circulation inside the motor housing 300. Two air vortices of different sizes are formed in the four corner spaces of the motor housing 300. Moreover, the air at the upper and lower ends of the motor housing 300 circulates with each other. The air flows from the upper end of the motor housing to the upper end through the air gap between the motor stator and the motor rotor, and then returns from the upper end of the motor housing to the lower end through the heat dissipation channel 141, forming a complete air circulation. The speed of the air circulation is related to the rotational speed of the motor rotor. The faster the rotational speed, the faster the air circulation. During the air flow, a wind-cooling effect is formed to dissipate heat from the motor stator and the motor rotor.

[0065] The following table 1 illustrates the temperature rise of a permanent magnet synchronous motor with a 22KW motor rotor equipped with a heat dissipation structure according to the present disclosure and a permanent magnet synchronous motor without the heat dissipation structure.

[0066] Table 1

[0067]

[0068] In a conventional rotor structure, the rear coil is closer to the additionally installed fan, while the front coil is farther from the fan. In a permanent magnet synchronous motor including the heat dissipation structure according to this disclosure, the temperature difference between the front and rear coils is noticeably reduced. This indicates that the heat dissipation structure accelerates airflow within the motor, allowing for sufficient heat exchange between the front and rear coils and reducing the temperature difference. Furthermore, the temperature rise of both the front and rear coils is lower than in a conventional rotor structure, also due to the improved heat dissipation efficiency and reduced temperature rise caused by the airflow within the motor.

[0069] As shown in Figure 12, there are two air vortices of different sizes inside the motor housing, rotating in opposite directions. One vortex facilitates air inflow, while the other facilitates air outflow. When air first flows in, its velocity is relatively slow. One vortex accelerates the inflowing air, and when the air velocity increases to a certain level, it enters the other vortex, which expels the faster-moving air, thus completing the air circulation.

[0070] According to this disclosure, a heat dissipation fan with axial displacement is constructed on the rotor core using a plastic encapsulation material. When the motor rotor rotates, it accelerates the airflow inside the motor, achieving a cooling effect and improving the motor's heat dissipation efficiency. Therefore, there is no need to install an additional fan for heat dissipation, reducing motor costs and improving motor operating efficiency.

[0071] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning understood by one of ordinary skill in the art to which this utility model pertains. The terms “first,” “second,” and similar terms used in this utility model patent application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, “an” or “a” and similar terms do not necessarily indicate a quantity limitation. Terms such as “comprising” or “including” mean that the element or object preceding the word encompasses the element or object listed following the word and its equivalents, without excluding other elements or objects. Terms such as “connected” or “linked” are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as “upper,” “lower,” “left,” and “right” are used only to indicate relative positional relationships; these relative positional relationships may change accordingly when the absolute position of the described object changes.

[0072] The exemplary embodiments of the present invention have been described in detail above with reference to preferred embodiments. However, those skilled in the art will understand that various modifications and alterations can be made to the above specific embodiments without departing from the concept of the present invention, and various combinations can be made to the various technical features and structures proposed by the present invention without exceeding the protection scope of the present invention, which is determined by the appended claims.

Claims

1. A motor rotor (100), characterized in that, include: The rotor core (110) includes an outer core (111) located radially outward and an inner core (112) located radially inward; a permanent magnet (120) arranged circumferentially in the outer core (111); an injection-molded portion (130) that at least partially covers the rotor core (110) circumferentially and covers the ends of the rotor core (110) to form a first end (100a) and a second end (100b) of the motor rotor (100) that are axially opposed to each other; and a heat dissipation structure including a heat dissipation fan (140) formed by the injection-molded portion in a region of the inner core (112) and a heat dissipation channel (141) formed between the heat dissipation fan (140), wherein the heat dissipation fan (140) extends offset in a portion of the axial direction, thereby causing the heat dissipation channel (141) to extend offset axially.

2. The motor rotor (100) according to claim 1, characterized in that, The heat dissipation channel (141) extends from the first end (100a) to the second end (100b) and includes at least a first channel section (141a) and a second channel section (141b) that is axially offset relative to the first channel section (141a).

3. The motor rotor (100) according to claim 1, characterized in that, The inner core (112) includes a plurality of reinforcing ribs (113), wherein the injection molding part covers the reinforcing ribs (113) to form the heat dissipation fan body (140).

4. The motor rotor (100) according to claim 3, characterized in that, The extension line of the reinforcing rib (113) does not pass through the center (O) of the rotor (100).

5. The motor rotor (100) according to claim 3, characterized in that, The heat dissipation fan body (140) includes at least a first fan body (140a) and a second fan body (140b) that are offset from each other along the axial direction. The injection molding part covers the reinforcing rib (113) from the first end (100a) to form the first fan body (140a), and the injection molding part covers the reinforcing rib (113) from the second end (100b) to form the second fan body (140b).

6. The motor rotor (100) according to claim 5, characterized in that, The rotor core (110) has a two-stage structure.

7. The motor rotor (100) according to claim 6, characterized in that, The rotor core (110) includes a first rotor core (110a) with a first reinforcing rib (113a) and a second rotor core (110b) with a second reinforcing rib (113b) that are axially opposed to each other.

8. The motor rotor (100) according to claim 7, characterized in that, The first fan body (140a) includes the first reinforcing rib (113a) and an injection-molded portion covering the first reinforcing rib (113a), and the second fan body (140b) includes the second reinforcing rib (113b) and an injection-molded portion covering the second reinforcing rib (113b).

9. The motor rotor (100) according to claim 5, characterized in that, The first sector (140a) and the second sector (140b) are offset from each other by a shift angle (α) of 10° to 30°.

10. The motor rotor (100) according to claim 5, characterized in that, The circumferential width of the second sector (140b) is less than the minimum circumferential width at the point where the first channel section (141a) and the second channel section (141b) are staggered and transition.

11. The motor rotor (100) according to claim 5, characterized in that, The circumferential width of the first sector (140a) is smaller than the circumferential width of the second sector (140b).

12. The motor rotor (100) according to claim 5, characterized in that, The cooling fan (140) also includes end fans (140d, 140e) located axially outside the first fan (140a) and / or the second fan (140b).

13. The motor rotor (100) according to claim 12, characterized in that, The end fan body (140d, 140e) is formed by injection molding.

14. The motor rotor (100) according to claim 1, characterized in that, The cooling fan body (140) is constructed in a centrally symmetrical manner.

15. A permanent magnet synchronous motor, characterized in that, It includes a motor stator and a motor rotor (100) as described in any one of claims 1 to 14 above.

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