Single-magnetic-pole brushless direct current motor

Abstract

A stator comprises an annular silicon steel sheet, a plurality of salient poles are evenly distributed on the inner ring of the annular silicon steel sheet in the radial direction of the annular silicon steel sheet, and coil windings are wound around the salient poles; the rotor comprises a rotatable magnetic conductive ring located on the inner ring of the annular silicon steel sheet, a plurality of magnetic steels are uniformly arranged on the outer ring of the magnetic conductive ring in the radial direction, the polarities of magnetic poles on the sides, facing the salient poles, of all the magnetic steels are the same, and the magnetic steels and the salient poles are asymmetrically arranged; according to the scheme, repulsive force is formed between the stator and the rotor to drive the rotor to rotate through the position relation of the salient poles on the stator and the magnetic steel on the rotor and the structure that all the magnetic steel faces the salient poles with the same polarity, eddy current loss generated when a stator alternating magnetic field penetrates through rotor permanent magnets is avoided or weakened, and the conversion efficiency between electric energy and mechanical energy of the motor is improved; heating caused by an eddy current effect is reduced, temperature rise of the rotor is effectively controlled, permanent magnet demagnetization caused by high temperature is avoided, and the effective service life of the motor is prolonged.

Description

Technical Field

[0001] This application relates to the technical field of motors, and specifically to a single-pole brushless DC motor. Background Art

[0002] As is well known, in the fields of electromechanical technology and engineering, motors are generally divided into three categories: DC motors, asynchronous motors, and synchronous motors. With the progress of modern industry and the requirement of energy conservation and consumption reduction, asynchronous motors have been gradually phased out. In recent years, brushless DC motors developed in permanent magnet motors have been widely used due to their advantages such as simple structure, compact volume, high power density, high efficiency, fast dynamic response, and easy control.

[0003] The structure of a brushless DC motor usually consists of a permanent magnet material, such as neodymium iron boron strong magnetic material, as the rotor, and a copper wire winding wound around a soft magnetic material - silicon steel sheet to form the stator. Its basic principle is that through the electronic commutation function of the motor controller, three phase voltages with a phase angle of 120 degrees are output in sequence, and according to a certain logical sequence, a square wave current with two-phase conduction is supplied to the stator winding to form a rotating magnetic field in the stator to drive the rotor to rotate, realizing the conversion between electrical energy and mechanical energy.

[0004] There is a problem of eddy current loss in current permanent magnet motors: Currently, most permanent magnet motors use neodymium iron boron strong magnetic material as the permanent magnet of the rotor. Neodymium iron boron material belongs to a conductor. When the motor is running, the alternating rotating magnetic field formed by the stator winding and the magnetic field of the rotor are superimposed on each other, generating an eddy current induction effect and heating up. Moreover, the eddy current induction effect increases in a square relationship with the frequency of the stator alternating magnetic field. Eddy current heating not only reduces the conversion efficiency of electrical energy and mechanical energy of the motor, but also as the frequency of the alternating magnetic field increases, the eddy current heat generation increases, causing the temperature of the rotor to rise, resulting in demagnetization of the permanent magnet of the rotor and reducing the effective life of the motor. Summary of the Invention

[0005] To overcome the above-mentioned drawbacks, the purpose of this application is to provide a single-pole brushless DC motor, thereby effectively solving the above-mentioned technical problems.

[0006] To achieve the above purpose, this application adopts the following technical solutions:

[0007] A single-pole brushless DC motor provided by this application, characterized in that it includes a housing, and a stator and a rotor are arranged inside the housing, wherein,

[0008] The stator includes an annular silicon steel sheet, and a plurality of salient poles are evenly arranged along the radial direction of the inner circle of the annular silicon steel sheet, and coil windings are wound around the salient poles;

[0009] The rotor includes a magnetic conductive ring rotatably located within the inner ring of the annular silicon steel sheet. A plurality of permanent magnets are uniformly arranged along the radial direction on the outer ring of the magnetic conductive ring. The magnetic poles on the side of all the permanent magnets facing the salient poles have the same polarity, and the number of the permanent magnets is different from the number of the salient poles so that the permanent magnets and the salient poles are asymmetrically arranged;

[0010] A rotating induced magnetic field is formed by energizing the coil windings wound around the salient poles, and the rotor is driven to rotate in the form of repulsive force.

[0011] Further, a Hall magnetic induction signal sensor is embedded in the part of the salient pole close to the permanent magnet.

[0012] Further, the rotor further includes a bearing and a central shaft. The magnetic conductive ring is positioned by the bearing to be mounted on the central shaft, and the permanent magnets are embedded in the circumferential outer side of the magnetic conductive ring.

[0013] Further, the coil windings wound around the plurality of salient poles have the same winding direction, the same power supply direction, and are input with a phase angle of 72 degrees to each other.

[0014] Further, the ratio of the number of the salient poles to the number of the permanent magnets is 5:4.

[0015] Further, the ratio of the number of the salient poles to the number of the permanent magnets is 3:2.

[0016] Further, the housing includes a magnetic conductive housing, a front end cover, and a rear end cover. The magnetic conductive housing is connected to the front end cover and the magnetic conductive housing is connected to the rear end cover by fastening screws. The stator and the rotor are arranged in the internal area formed by the magnetic conductive housing, the front end cover, and the rear end cover.

[0017] Further, the inside of the central shaft is a hollow cavity, and the three-phase wire bundles of the coil windings pass through the hollow cavity from inside the housing and extend to the outside of the housing.

[0018] Beneficial effects

[0019] A single-pole brushless DC motor provided by the present application forms a repulsive force between the stator and the rotor through the positional relationship between the salient poles on the stator and the permanent magnets on the rotor and the structure in which all the permanent magnets face the salient poles with the same polarity, driving the rotor to rotate, avoiding or weakening the eddy current loss generated by the alternating magnetic field of the stator penetrating the permanent magnet of the rotor, improving the conversion efficiency between the electrical energy and the mechanical energy of the motor, reducing the heat generated by the eddy current effect, effectively controlling the temperature rise of the rotor, avoiding the demagnetization of the permanent magnet caused by high temperature, and prolonging the effective life of the motor. Description of the drawings

[0020] The accompanying drawings are used to provide an understanding of the technical solutions of the present disclosure and form a part of the specification. Together with the embodiments of the present disclosure, they are used to explain the technical solutions of the present disclosure and do not constitute a limitation to the technical solutions of the present disclosure. The shapes and sizes of the components in the accompanying drawings do not reflect the actual proportions, and the purpose is only to schematically illustrate the content of the present application.

[0021] Figure 1 It is a cross-sectional view of the overall structure of the motor provided by an embodiment of the present application.

[0022] Figure 2 It is a schematic diagram of the stator and rotor structures of the motor provided by an embodiment of the present application.

[0023] Figure 3 It is the principle of the working state of the motor provided by an embodiment of the present application Figure 1 。

[0024] Figure 4 It is the principle of the working state of the motor provided by an embodiment of the present application Figure 2 。

[0025] Figure 5 It is the principle of the working state of the motor provided by an embodiment of the present application Figure 3 。

[0026] Figure 6 It is the principle of the working state of the motor provided by an embodiment of the present application Figure 4 。

[0027] Figure 7 It is the principle of the working state of the motor provided by an embodiment of the present application Figure 5 。

[0028] In the above accompanying drawings,

[0029] 1. Magnetic conductive housing; 2. Front end cover; 3. Rear end cover; 4. Fastening screw; 5. Central shaft; 6. Bearing; 7. Ring-shaped silicon steel sheet; 8. Pole projection; 9. Coil winding; 10. Magnetic conductive ring; 11. Permanent magnet; 12. Hall magnetic induction signal sensor; 13. Three-phase wire harness. Detailed implementation manners

[0030] The above solutions will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are for illustrative purposes only and do not limit the scope of the present application. The implementation conditions adopted in the embodiments can be further adjusted according to the conditions of specific manufacturers, and the implementation conditions not specified are usually those in conventional experiments.

[0031] Unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present disclosure shall have the ordinary meanings understood by those of ordinary skill in the art to which this application belongs. The terms "first", "second" and similar words used in the embodiments of the present disclosure do not denote any order, quantity or importance, but are only used to distinguish different components. Words such as "including" or "comprising" mean that the elements or objects appearing before this word cover the elements or objects listed after this word and their equivalents, without excluding other elements or objects. Words such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. In this article, "electrical connection" includes the case where components are connected together through elements having a certain electrical effect. There is no particular limitation on the "element having a certain electrical effect" as long as it can transfer electrical signals between the components to be connected. The "element having a certain electrical effect" can be, for example, an electrode or a wiring, or a switching element such as a transistor, or other functional elements such as a resistor, an inductor or a capacitor. The terms "upper", "lower", "left", "right", etc. are only used to represent relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0032] In this application, the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "middle", etc. is based on the orientation or positional relationship shown in the drawings. These terms are mainly used to better describe this application and its embodiments, and are not used to limit that the indicated device, element or component must have a specific orientation, or be constructed and operated in a specific orientation.

[0033] Embodiment

[0034] An embodiment of the present application provides a single-pole brushless DC motor, as Figure 1 shown. The motor includes a housing, and the housing includes a magnetic conductive outer shell 1, a front end cover 2 and a rear end cover 3. The magnetic conductive outer shell 1 is connected to the front end cover 2 and the magnetic conductive outer shell 1 is connected to the rear end cover 3 by fastening screws 4. The stator and the rotor are arranged in the internal area formed by the magnetic conductive outer shell 1, the front end cover 2 and the rear end cover 3. The center shaft 5 has a hollow cavity inside. The three-phase wire bundles 13 of the coil windings 9 on the stator pass through the hollow cavity inside the housing and extend to the outside of the housing;

[0035] As Figure 2 shown, the stator includes an annular silicon steel sheet 7. A plurality of salient poles 8 (5 salient poles 8 are adopted in this embodiment) are uniformly arranged along the radial direction of the inner circle of the annular silicon steel sheet 7. Coil windings 9 are wound around each salient pole 8. The winding directions of the coil windings 9 wound around each salient pole 8 are the same, the power supply directions are the same, and they are input with a phase angle of 72 degrees to each other;

[0036] The rotor includes a bearing 6, a central shaft 5, and a magnetic conductive ring 10. The magnetic conductive ring 10 is located inside the inner ring of the annular silicon steel sheet 7, and the magnetic conductive ring 10 is positioned by the bearing 6 to be installed on the central shaft 5. The permanent magnets 11 are embedded in the circumferential outer side of the magnetic conductive ring 10. There are multiple permanent magnets 11 (4 permanent magnets 11 are adopted in this embodiment), and the 4 permanent magnets 11 are evenly arranged radially along the outer ring of the magnetic conductive ring 10. The magnetic pole polarities of all the permanent magnets 11 on the side facing the salient poles 8 are the same (N-N-N-N or S-S-S-S). The number of permanent magnets 11 is different from the number of salient poles 8 so that the permanent magnets 11 and the salient poles 8 are asymmetrically arranged. In this embodiment, the number of salient poles 8 and permanent magnets 11 is set as 5:4. In some other embodiments, the number of salient poles 8 and permanent magnets 11 can be set as 3:2. The coil windings 9 wound around the salient poles 8 are energized to form a rotating induction magnetic field to drive the rotor to rotate in the form of repulsive force. A Hall magnetic induction signal sensor 12 is embedded in the part of the salient pole 8 close to the permanent magnet 11. The Hall magnetic induction signal sensor 12 is used to sense the running position of the rotor and feedback it to the motor controller. The working principle of this embodiment is as follows:

[0037] Combined Figures 3 - 7 As shown, the 5 salient poles on the motor stator annular silicon steel sheet are respectively A, B, C, D, E, and the 4 permanent magnets on the electronic rotor magnetic conductive ring are respectively N1, N2, N3, N4.

[0038] The stator adopts a five-phase winding structure. When the rotor and the stator are in the attached Figure 3 As shown in the position as the starting point, that is, when the magnetic pole N of the permanent magnet N3 of the rotor is between the stator salient poles C and D, the motor controller processes the position signals of the Hall position sensor and supplies power to the windings A, B, and C respectively, so that the windings A, B, and C and the permanent magnets N1, N2, N3 form a repulsive force to drive the rotor to rotate clockwise by 72 degrees, completing the first step of operation. By analogy, a total of 5 steps are required to complete a 360-degree rotation cycle in one week;

[0039] According to the above content, it can be known that when the motor rotor rotates one week, it is divided into 5 steps. Each step rotates 72 degrees of mechanical angle.

[0040] Step 1, when the rotor and the stator are in the Figure 3 As shown in the position, that is, when the magnetic pole N of the permanent magnet N3 of the rotor is between the stator salient poles C and D, the motor controller processes the position signals of the Hall position sensor and supplies power to the coil windings on the stator salient poles A, B, and C respectively, so that the stator salient poles A, B, and C and the permanent magnets N1, N2, N3 form a repulsive force to drive the rotor to rotate clockwise by 72 degrees and rotate to the Figure 4 As shown in the position;

[0041] Step 2, when the rotor and the stator are in the Figure 4When in the position shown, that is, when the N pole of the rotor magnet N3 is between the stator salient poles D and E, the motor controller processes the position signals of the Hall position sensor and supplies power to the coil windings on the stator salient poles B, C, and D respectively, so that the stator salient poles B, C, and D and the magnets N1, N2, and N3 form repulsive forces to drive the rotor to rotate clockwise by 72 degrees and rotate to Figure 5 the position shown;

[0042] Step 3. When the rotor and the stator are in Figure 5 the position shown, that is, when the N pole of the rotor magnet N3 is between the stator salient poles E and A, the motor controller processes the position signals of the Hall position sensor and supplies power to the coil windings on the stator salient poles C, D, and E respectively, so that the stator salient poles C, D, and E and the magnets N1, N2, and N3 form repulsive forces to drive the rotor to rotate clockwise by 72 degrees and rotate to Figure 6 the position shown;

[0043] Step 4. When the rotor and the stator are in Figure 6 the position shown, that is, when the N pole of the rotor magnet N3 is between the stator salient poles A and B, the motor controller processes the position signals of the Hall position sensor and supplies power to the coil windings on the stator salient poles D, E, and A respectively, so that the stator salient poles D, E, and A and the magnets N1, N2, and N3 form repulsive forces to drive the rotor to rotate clockwise by 72 degrees and rotate to Figure 7 the position shown;

[0044] Step 5. When the rotor and the stator are in Figure 7 the position shown, that is, when the N pole of the rotor magnet N3 is between the stator salient poles B and C, the motor controller processes the position signals of the Hall position sensor and supplies power to the coil windings on the stator salient poles E, A, and B respectively, so that the stator salient poles E, A, and B and the magnets N1, N2, and N3 form repulsive forces to drive the rotor to rotate clockwise by 72 degrees and rotate to position ①;

[0045] The above 5 steps complete a power supply cycle, the rotor rotates 360 degrees, and this process repeats continuously, and the rotor of the motor forms continuous rotation.

[0046] The above embodiments are only used to illustrate the technical concept and features of the present application, and the purpose is to enable those who are familiar with this technology to understand the content of the present application and implement it accordingly, and it cannot be used to limit the protection scope of the present application. Any equivalent transformation or modification made in the spirit of the present application should be covered within the protection scope of the present application.

Claims

1. A single-pole brushless DC motor, characterized in that: It includes a housing, and a stator and a rotor are arranged inside the housing. Among them, the stator includes an annular silicon steel sheet, and a plurality of salient poles are evenly arranged along the radial direction of the inner circle of the annular silicon steel sheet, and a coil winding is wound around the salient poles; the rotor includes a magnetic conductive ring that can rotate inside the inner circle of the annular silicon steel sheet, and a plurality of permanent magnets are evenly arranged along the radial direction of the outer circle of the magnetic conductive ring. The magnetic pole polarities of all the permanent magnets on the side facing the salient poles are the same, and the number of the permanent magnets is different from the number of the salient poles so that the permanent magnets and the salient poles are asymmetrically arranged; When the coil winding wound around the salient poles is energized, a rotating induction magnetic field is formed to drive the rotation of the rotor in the form of repulsive force.

2. The single-pole brushless DC motor according to claim 1, wherein: A Hall magnetic induction signal sensor is embedded in the part of the salient pole close to the permanent magnet.

3. The single-pole brushless DC motor according to claim 1, wherein: The rotor further includes a bearing and a central shaft. The magnetic conductive ring is positioned by the bearing to be installed on the central shaft, and the permanent magnets are embedded in the circumferential outer side surface of the magnetic conductive ring.

4. The single-pole brushless DC motor according to claim 1, wherein: The winding directions of the coil windings wound around the plurality of salient poles are the same, the power supply directions are the same, and they are input with a phase angle of 72 degrees to each other.

5. The single-pole brushless DC motor according to claim 1, wherein: The ratio of the number of the salient poles to the number of the permanent magnets is 5:

4.

6. The single-pole brushless DC motor according to claim 1, wherein: The ratio of the number of the salient poles to the number of the permanent magnets is 3:

2.

7. The single-pole brushless DC motor according to claim 1, wherein: The housing includes a magnetic conductive outer shell, a front end cover and a rear end cover. The magnetic conductive outer shell is connected to the front end cover and the magnetic conductive outer shell is connected to the rear end cover by fastening screws. The stator and the rotor are arranged in the internal area formed by the magnetic conductive outer shell, the front end cover and the rear end cover.

8. The single-pole brushless DC motor according to claim 3, wherein: The inside of the central shaft is a hollow cavity, and the three-phase wire bundles of the coil winding extend from inside the housing through the hollow cavity to the outside of the housing.

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