Self-ventilated rotor and electric machine

Abstract

The application provides a self-ventilation rotor, comprising a rotor core, a plurality of axial ventilation channels are arranged in the rotor core; further comprising a balance disc, the balance disc is provided with ventilation holes corresponding to the ventilation channels, the ventilation holes comprise first ventilation holes and second ventilation holes, the height of the edge of the first ventilation hole far from the center of the rotor is greater than the height of the edge close to the center of the rotor, the height of the edge of the second ventilation hole close to the center of the rotor is greater than the height of the edge far from the center of the rotor; the rotor is provided with the balance disc at both ends, and the same ventilation channel is respectively corresponding to the first ventilation hole and the second ventilation hole at both sides, so that: when the rotor rotates, one end provided with the first ventilation hole forms positive pressure, and one end provided with the second ventilation hole forms negative pressure, so that air self-flows in the ventilation channel.

Description

Technical Field

[0001] This invention relates to the field of motor technology, and in particular to a self-ventilated rotor and motor. Background Technology

[0002] Permanent magnet synchronous motors are a new type of direct-drive torque servo motor. Due to their advantages such as high output torque, low speed, compact structure, and high energy efficiency, they are particularly suitable for low-speed drive applications and are widely used in many fields such as metallurgical machinery, electric vehicles, and CNC machine tools. For permanent magnet motors, the overall performance largely depends on the permanent magnets. Permanent magnet motors have high torque density and generate significant heat. When the motor temperature reaches or exceeds the stable operating temperature, thermal demagnetization of the permanent magnets and severe insulation aging can easily occur, leading to reduced motor performance and lifespan. Therefore, adopting a reasonable cooling method to control the motor temperature rise is essential. Summary of the Invention

[0003] In order to overcome the above-mentioned technical defects, the purpose of this invention is to provide a self-ventilated rotor and motor that only requires design of the balance disc without affecting the existing rotor structure.

[0004] This invention discloses a self-ventilated rotor, comprising a rotor core with a plurality of axial ventilation channels inside; and a balance disc with ventilation holes corresponding to the ventilation channels. The ventilation holes include a first ventilation hole and a second ventilation hole. The height of the edge of the first ventilation hole away from the rotor center is greater than the height of the edge of the second ventilation hole near the rotor center, and the height of the edge of the second ventilation hole near the rotor center is greater than the height of the edge away from the rotor center. The balance disc is located at both ends of the rotor, and the first ventilation hole and the second ventilation hole are respectively located on both sides of the same ventilation channel, such that when the rotor rotates, a positive pressure is formed at the end with the first ventilation hole and a negative pressure is formed at the end with the second ventilation hole, thereby allowing air to circulate within the ventilation channel.

[0005] Preferably, the balance disc includes a disc body and an edge portion. The ventilation hole is disposed on the disc body, and the edge portion is disposed on the periphery of the disc body, with the edge portion being higher than the disc body. A protrusion is provided on the edge portion, with the top surface of the protrusion being higher than the disc body. The protrusion and the first ventilation hole are located in the same radial direction, and the protrusion extends radially to at least the edge of the first ventilation hole, thereby making the height of the edge of the first ventilation hole away from the rotor center greater than the height of the edge of the first ventilation hole closer to the rotor center. A notch is provided on the edge portion, with the bottom surface of the notch being lower than the disc body. The notch and the second ventilation hole are located in the same radial direction, and the notch extends radially to communicate with the second ventilation hole, thereby making the height of the edge of the second ventilation hole closer to the rotor center greater than the height of the edge of the second ventilation hole away from the rotor center.

[0006] Preferably, the height of the bump is the same as the height of the edge portion.

[0007] Preferably, the notch is a through hole.

[0008] Preferably, the protrusion extends radially into the first ventilation hole, and the disc portion located on the side of the second ventilation hole near the center of the rotor extends radially into the second ventilation hole, thereby causing the first ventilation hole and the second ventilation hole to be offset in the same radial direction.

[0009] Preferably, the first ventilation hole and the second ventilation hole are arranged alternately in the circumferential direction on the balance disc, so that the airflow direction of adjacent ventilation channels is opposite.

[0010] Preferably, the radial cross-sectional area of ​​the second ventilation hole is smaller than the radial cross-sectional area of ​​the ventilation channel of the rotor.

[0011] Preferably, the number of ventilation channels is equal to the number of motor poles.

[0012] The present invention also discloses an electric motor, including the aforementioned self-ventilated rotor.

[0013] Compared with existing technologies, the above technical solution has the following advantages:

[0014] 1. The rotor and balance disc of the present invention are provided with corresponding ventilation channels and ventilation holes to form an air cooling channel parallel to the rotating shaft for rotor ventilation and heat dissipation; the ventilation holes on the balance disc include two different forms, and the two types of ventilation holes are respectively arranged on both sides of the same ventilation channel on the rotor, so that a pressure difference is generated on both sides of the ventilation channel when the rotor rotates, thereby driving air flow to form a forced convection effect, enhancing heat dissipation, solving the problem of excessively high rotor temperature caused by poor heat dissipation of water-cooled motor rotor, and reducing the risk of magnet demagnetization;

[0015] 2. This invention only changes the local features of the balance disc, without requiring additional medium to cool the rotor, thus not affecting the overall rotor structure. Attached Figure Description

[0016] Figure 1 A schematic diagram of the structure of the self-ventilated rotor provided by the present invention;

[0017] Figure 2 This is a schematic diagram of the ventilation direction of the self-ventilated rotor provided by the present invention.

[0018] Wherein: 1-rotor, 2-balance disc, 3-shaft, 4-first ventilation hole, 5-second ventilation hole, 6-protrusion, 7-notch, 8-ventilation channel. Detailed Implementation

[0019] The advantages of the present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments.

[0020] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0021] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The singular forms “a,” “the,” and “the” as used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0022] It should be understood that although the terms first, second, third, etc., may be used in this disclosure to describe various information, such information should not be limited to these terms. These terms are used only to distinguish information of the same type from one another. For example, without departing from the scope of this disclosure, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0023] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention 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 invention.

[0024] In the description of this invention, unless otherwise specified and limited, it should be noted that the terms "installation", "connection" and "linking" should be interpreted broadly. For example, they can refer to mechanical or electrical connections, or internal connections between two components. They can be direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0025] In the following description, suffixes such as "module," "part," or "unit" used to denote elements are used only for the convenience of the description of the invention and have no specific meaning in themselves. Therefore, "module" and "part" can be used interchangeably.

[0026] See appendix Figure 1 This invention discloses a self-ventilated rotor 1, comprising a rotor core and a rotor balance disc 2, which are tightly fitted together during assembly. The rotor core is part of the motor's magnetic circuit, forming the entire magnetic circuit of the motor together with the stator core and the air gap. The rotor core is generally made of stacked silicon steel sheets with a certain inner thickness (e.g., 0.5 mm). In medium and small AC motors, the rotor core is mostly directly mounted on the motor shaft. In large AC motors, the rotor core is mounted on a rotor support, which is fitted onto the rotating shaft 3. The rotor balance disc 2 is generally located at both ends of the rotor to achieve dynamic balance.

[0027] The rotor core of the present invention is provided with a plurality of axial ventilation channels 8, and the balance disk 2 is provided with ventilation holes corresponding to the ventilation channels 8. After the balance disk 2 is provided at both ends of the rotor 1, the two ends of the axial ventilation channel 8 in the rotor core are respectively connected to the ventilation holes. Thus, the ventilation channel 8 combined with the ventilation holes at both ends forms a channel that runs through the balance disk 2 at both ends and the interior of the rotor 1. This channel can circulate air and serve as a cooling channel inside the rotor 1.

[0028] Specifically, the ventilation holes on the balance disc 2 have two structural forms, which can be summarized as the first ventilation hole 4 and the second ventilation hole 5. The difference is that the height of the edge of the first ventilation hole 4 away from the center of the rotor 1 is greater than the height of the edge of the first ventilation hole 4 near the center of the rotor 1, while the height of the edge of the second ventilation hole 5 near the center of the rotor 1 is greater than the height of the edge of the second ventilation hole 5 away from the center of the rotor 1.

[0029] In layman's terms, there is a height difference between the edges of the two types of ventilation holes. That is, the two edges of the hole (roughly referring to the edge closer to the center of rotor 1 and the edge farther from the center of rotor 1) are not in the same axial direction. Therefore, for the same ventilation hole, it can be understood that its hole surface is a slope.

[0030] The two different ventilation holes (first ventilation hole 4 and second ventilation hole 5) of the present invention have different inclination directions of their slopes, and the first ventilation hole 4 and second ventilation hole 5 with different structural forms are respectively placed on both sides of the same ventilation channel 8, so that when the rotor 1 rotates, the end with the first ventilation hole 4 forms a positive pressure and the end with the second ventilation hole 5 forms a negative pressure, that is, a pressure difference is generated on both sides of the ventilation channel 8, thereby allowing air to circulate within the ventilation channel 8 to achieve the effect of heat dissipation, solving the problem of excessively high rotor temperature caused by poor heat dissipation of the water-cooled motor rotor 1, and reducing the risk of demagnetization of the magnets.

[0031] It should be noted that the "height" mentioned here refers to the height of rotor 1 when it is "standing" axially. When rotor 1 is in a "lying" state, there is no such description of "height". For a simpler understanding, the "height" mentioned here can be described as the difference in axial position. Therefore, "the height of the edge of the first ventilation hole 4 away from the center of rotor 1 is greater than the height of the edge of the first ventilation hole 4 closer to the center of rotor 1" can be understood as the inclined surface of the first ventilation hole 4 being inclined towards the center of rotor 1. Similarly, "the height of the edge of the second ventilation hole 5 closer to the center of rotor 1 is greater than the height of the edge of the second ventilation hole 5 away from the center of rotor 1" can be understood as the inclined surface of the second ventilation hole 5 being inclined towards the edge of rotor 1.

[0032] To facilitate understanding, the principle of air self-circulation achieved through the structure of the two ventilation holes in this invention can be understood by referring to the airflow principle of a fan blade. The principle by which a fan blade blows air is that when the blade rotates, it compresses the air on the upper surface (the area under force) in an oblique manner, causing it to move perpendicular to the blade surface. The blade needs a certain angle to push the air (it needs to be able to generate an upward force perpendicular to the plane of rotation). The streamlined shape of the blade is to avoid unnecessary frictional loss of kinetic energy and also to reduce noise. When the blade rotates, the upper air is forced to "flow away," creating negative pressure in its original location. The lower air, due to this negative pressure, "flows into" this area, thus creating airflow.

[0033] The process of generating airflow in a fan is mainly as follows: the fan blades rotate, pushing the air particles within the volume of the blades downwards, causing the air pressure at the air inlet to continuously decrease and the air pressure at the air outlet to continuously increase, resulting in an axial increase in air pressure throughout the entire fan blade area; because the external air pressure at the air inlet is greater than the air pressure at the air inlet, external air is replenished, and the replenished air is also transported to the high-pressure area by the blades, causing the air pressure at the air inlet to decrease further, attracting more air to replenish this low-pressure area, and so on, until the amount of air replenished equals the amount of air transported by the fan and the amount of air flowing out of the air outlet, reaching a dynamic equilibrium.

[0034] Furthermore, the balance disc 2 includes a disc body and an edge portion. The disc body and edge portion are integral parts, distinguished only by their different heights (refer to the aforementioned description of "height"). Specifically, the edge portion is higher than the disc body portion; it can even be understood as a raised ring around the outer edge of the disc body portion. The ventilation holes of this invention are located on the disc body portion. During assembly, the edge portion can be used for support or other functions, and because it is higher (more prominent), the ventilation holes will not be blocked.

[0035] The structural feature of "uneven edge height" between the first ventilation hole 4 and the second ventilation hole 5 is achieved by combining the features of the edge portion.

[0036] Specifically, for the first ventilation hole 4, a protrusion 6 is provided on the edge. The top surface of the protrusion 6 is higher than the disk body, that is, there is an axial positional difference between the protrusion 6 and the disk body. The protrusion 6 extends at least radially to the edge of the first ventilation hole 4, so that the height of the edge of the first ventilation hole 4 away from the center of the rotor 1 is greater than the height of the edge of the first ventilation hole 4 closer to the center of the rotor 1.

[0037] In the preferred embodiment provided by the present invention, the protrusion 6 and the first ventilation hole 4 are located in the same radial direction, that is, the center of the protrusion 6, the first ventilation hole 4, and the rotor 1 are on the same straight line; while in other preferred embodiments, the protrusion 6 and the first ventilation hole 4 may not be located in the same radial direction, but it still extends at least radially to the edge of the first ventilation hole 4. In this structure, the protrusion 6 is not on the same straight line as the center of the first ventilation hole 4 and the rotor 1, but the protrusion 6 is obliquely connected to the edge of the first ventilation hole 4.

[0038] For the second ventilation hole 5, a notch 7 is provided on the edge. The bottom surface of the notch 7 is lower than the disc body, that is, there is an axial position difference between the notch 7 and the disc body. The notch 7 extends radially to communicate with the second ventilation hole 5, so that the height of the edge of the second ventilation hole 5 near the center of the rotor 1 is greater than the height of the edge away from the center of the rotor 1.

[0039] In the preferred embodiment provided by the present invention, the notch 7 and the second ventilation hole 5 are located in the same radial direction, that is, the center of the protrusion 6, the second ventilation hole 5, and the rotor 1 are on the same straight line; while in other preferred embodiments, the protrusion 6 and the second ventilation hole 5 may not be located in the same radial direction, but it still extends at least radially to the edge of the second ventilation hole 5. In this structure, the protrusion 6 is not on the same straight line as the center of the first ventilation hole 4 and the rotor 1, but the protrusion 6 is obliquely connected to the edge of the second ventilation hole 5.

[0040] Furthermore, in a preferred embodiment, the height of the protrusion 6 is the same as that of the edge portion, which can be understood as the protrusion 6 being a block that extends directly from the edge portion.

[0041] In a preferred embodiment, the notch 7 is a through hole, meaning that there is no component of the balance disc 2 at the notch 7, and the rotor 1 does not contact the balance disc 2.

[0042] Preferably, the protrusion 6 extends radially into the first ventilation hole 4, which can be understood as blocking the side of the first ventilation hole 4 away from the center of the rotor 1. The disc portion located on the side of the second ventilation hole 5 near the center of the rotor 1 extends radially into the second ventilation hole 5, which can be understood as blocking the side of the second ventilation hole 5 near the center of the rotor 1. This makes the first ventilation hole 4 and the second ventilation hole 5 offset in the same radial direction. It can be understood that the centers of the first ventilation hole 4 and the second ventilation hole 5 are not located on the same concentric circle, which further enhances the air circulation in the ventilation channel 8.

[0043] Preferably, the first ventilation hole 4 and the second ventilation hole 5 are arranged alternately along the circumference on the balance plate 2, so that the air flow direction of adjacent ventilation channels 8 is opposite, forming a forced convection effect.

[0044] Preferably, the number of ventilation channels 8 is equal to the number of motor poles. Therefore, generally, the interval angle between the first ventilation hole 4 and the second ventilation hole 5 on the same balance disc is 360° / number of motor poles. Correspondingly, the misalignment angle of the balance discs at both ends of the rotor is 360° / number of motor poles. In the preferred embodiment provided by the present invention, the number of motor poles is 8, and each balance disc 2 is provided with 8 ventilation holes, including 4 first ventilation holes and 4 second ventilation holes, with the first ventilation holes 4 and the second ventilation holes 5 arranged alternately.

[0045] In a preferred embodiment, the radial cross-sectional area of ​​the second ventilation hole 5 is smaller than the radial cross-sectional area of ​​the ventilation channel 8 of the rotor 1, thereby enhancing the ventilation effect.

[0046] The present invention also discloses an electric motor, including the self-ventilated rotor 1 described above. The electric motor can be a water-cooled motor, and the self-ventilated rotor 1 can effectively dissipate heat from the rotor 1.

[0047] It should be noted that the embodiments of the present invention have better implementability and are not intended to limit the present invention in any way. Any person skilled in the art may use the above-disclosed technical content to change or modify it into equivalent effective embodiments. However, any modifications or equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A self-ventilated rotor, characterized in that, Includes a rotor core, wherein the rotor core is provided with several axial ventilation channels; It also includes a balance disc, on which ventilation holes are provided corresponding to the ventilation channel. The ventilation holes include a first ventilation hole and a second ventilation hole. The height of the edge of the first ventilation hole away from the rotor center is greater than the height of the edge of the second ventilation hole near the rotor center is greater than the height of the edge of the second ventilation hole away from the rotor center. The rotor is provided with balance discs at both ends, and the first ventilation hole and the second ventilation hole are respectively located on both sides of the same ventilation channel, so that when the rotor rotates, the end with the first ventilation hole forms a positive pressure and the end with the second ventilation hole forms a negative pressure, thereby allowing air to circulate freely in the ventilation channel. The balance disc includes a disc body and an edge portion. The ventilation holes are located on the disc body, and the edge portion is located on the periphery of the disc body, with the edge portion being higher than the disc body. The edge portion is provided with a protrusion, the top surface of which is higher than the disc body portion; the protrusion and the first ventilation hole are located in the same radial direction, and the protrusion extends at least radially to the edge of the first ventilation hole, so that the height of the edge of the first ventilation hole away from the rotor center is greater than the height of the edge of the first ventilation hole closer to the rotor center; The edge portion has a notch, the bottom surface of which is lower than the disc portion; the notch and the second ventilation hole are located in the same radial direction, and the notch extends radially to communicate with the second ventilation hole, thereby making the height of the edge of the second ventilation hole closer to the rotor center greater than the height of the edge of the second ventilation hole farther from the rotor center.

2. The self-ventilated rotor according to claim 1, characterized in that, The height of the bump is the same as the height of the edge portion.

3. The self-ventilated rotor according to claim 1, characterized in that, The notch is a through hole.

4. The self-ventilated rotor according to claim 1, characterized in that, The protrusion extends radially into the first ventilation hole, while the disc portion located on the side of the second ventilation hole closer to the center of the rotor extends radially into the second ventilation hole, thereby causing the first ventilation hole and the second ventilation hole to be offset in the same radial direction.

5. The self-ventilated rotor according to claim 1, characterized in that, The first ventilation hole and the second ventilation hole are arranged alternately along the circumference on the balance disc, so that the airflow direction of adjacent ventilation channels is opposite.

6. The self-ventilated rotor according to claim 1, characterized in that, The radial cross-sectional area of ​​the second ventilation hole is smaller than the radial cross-sectional area of ​​the ventilation channel of the rotor.

7. The self-ventilated rotor according to claim 1, characterized in that, The number of ventilation channels is equal to the number of motor poles.

8. An electric motor, characterized in that, Includes the self-ventilated rotor as described in any one of claims 1-7.

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