Permanent magnet motor with asymmetric and eccentric magnetic poles

Abstract

The utility model provides an asymmetric and eccentric magnetic pole permanent magnet motor, each magnetic pole of a motor rotor is a sector-ring-shaped magnetic steel piece, and one magnetic pole is a positioning magnetic pole used for obtaining the angular displacement of the motor; the fan-ring-shaped central angle of the positioning magnetic pole is larger than that of other magnetic poles; the inner diameter or the outer diameter of the positioning magnetic pole is different from that of other magnetic poles, so that the cogging torque at the positioning magnetic pole is reduced when the rotor rotates; the magnetic pole structure provided by the utility model has the advantages of simple structure, asymmetry and eccentric distance, and not only reduces the size (total length) of the motor, but also reduces the cost of the motor on the premise of ensuring the control precision of the motor.

Description

Technical Field

[0001] The utility model relates to the technical field of motors, in particular to an asymmetric and eccentric magnetic pole permanent magnet motor. Background Art

[0002] As is known to all, ordinary small and medium-sized permanent magnet motors generally use symmetrical pole rotors, which are characterized by: n symmetrical poles are installed on the rotor, and the poles are symmetrically distributed around the circumference at intervals of NS. Figure 1 (Take an 8-pole motor as an example), the average angle occupied by the width of each magnetic pole is Υ (Υ=360 / n, 8-pole motor Υ=360 / 8=45,), and the size of each magnetic steel is exactly the same. In order to improve the control accuracy, it is generally necessary to install position encoders and other devices on the rotor, which not only lengthens the overall size of the motor, but also increases the cost of the motor. Summary of the invention

[0003] The utility model proposes an asymmetric and eccentric magnetic pole permanent magnet motor, providing a simple structure, an asymmetric magnetic pole structure with eccentricity, which reduces the motor volume (total length) and reduces the motor cost while ensuring the motor control accuracy.

[0004] The utility model adopts the following technical solutions.

[0005] A permanent magnet motor with an asymmetric and eccentric magnetic pole, wherein each magnetic pole of the motor rotor is a fan-shaped magnetic steel part, one of the magnetic poles is a positioning magnetic pole used to obtain the angular displacement of the motor; the central angle of the fan-shaped ring of the positioning magnetic pole is larger than that of the other magnetic poles; the inner diameter or outer diameter of the positioning magnetic pole is different from that of the other magnetic poles, so as to reduce the cogging torque at the positioning magnetic pole when the rotor rotates.

[0006] The magnetic inductor at the stator is a magnetic sensor; the positioning magnetic pole at the rotor matches the detection surface of the magnetic sensor, and the magnetic sensor is triggered when the positioning magnetic pole rotates to be adjacent to the magnetic sensor.

[0007] A positioning protrusion is provided at the lower end surface of the positioning magnetic pole, and the positioning protrusion is embedded in the installation groove of the rotor punching sheet.

[0008] Except for the positioning pole, the center angles of the other poles of the motor rotor are the same, all , let n be the number of poles of the motor, and the center angle of the locating magnetic pole is ,but (360- ) / (n-1).

[0009] Locate the center angle of the magnetic pole Size range, is the central angle of other magnetic poles 1.1 to 1.2 times of.

[0010] When the positioning pole differs from other poles only in outer diameter and has the same inner diameter as other poles, the thickness at the center axis of the positioning pole is the same as other poles, and the outer diameter of the magnetic steel is eccentric so that the thickness of the magnetic steel gradually decreases from the middle to both sides.

[0011] When the inner diameter and outer diameter of the positioning pole are different from those of other poles, let R be the radius of the rotor core punching sheet. If the thickness of the positioning pole magnetic steel part remains unchanged at all locations, the thickness of the magnetic steel part is the same as that of other magnetic steel parts. The distance that the inner diameter and outer diameter of the magnetic steel part deviate from the center of the rotor, that is, the eccentricity d=8%~12%R, makes the magnetic steel part closer to the center of the rotor.

[0012] The permanent magnet motor includes a casing, a stator, and a rotor. The stator and the rotor are both formed by stacking a number of punching sheets. The stator is arranged around the rotor. A coil is wound around the stator and a magnetic sensitive sensor is installed. An asymmetric and eccentric magnetic steel is installed on the rotor. A front cover and a rear cover are respectively arranged at the front and rear ends of the casing.

[0013] The beneficial effect of the utility model patent is that, since the rotor is provided with asymmetric and eccentric magnets, the asymmetric magnets cooperate with the magnetic sensor arranged on the stator (low cost and easy installation), which can easily obtain the angular displacement of the motor and improve the control accuracy. Since the asymmetry of the magnets increases the cogging torque, the present invention reduces the cogging torque by deviating the asymmetric magnets from the center of the rotor by a certain distance. Ultimately, the purpose of improving the control accuracy and reducing the cogging torque is achieved. Through this design, the motor volume (total length) can be reduced and the motor cost can be reduced while ensuring the control accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0015] Attached Figure 1 This is a schematic diagram of an ordinary permanent magnet motor under traditional technology (the motor is an 8-pole motor, the serial numbers 1-8 in the figure are the magnetic steel numbers of each pole of the motor, the central angle of each magnetic steel is 45 degrees, and the magnetic steels are arranged at intervals of NSNS);

[0016] Attached Figure 2 It is a schematic diagram of the permanent magnet motor of the solution described in the utility model (the magnetic steel of the positioning magnetic pole has a thickness variation, the outer diameter of the magnetic steel of the positioning magnetic pole is eccentric so that the thickness of each part of the magnetic steel is different, the central angle of the magnetic steel of the positioning magnetic pole is 52 degrees, and the central angle of the other magnetic poles is 44 degrees);

[0017] Attached Figure 3It is another schematic diagram of the permanent magnet motor of the solution described in the utility model (the thickness of the positioning pole remains unchanged but the pole is placed eccentrically, the thickness of the magnetic steel of the positioning pole is the same at all places, the inner diameter and outer diameter of the magnetic steel part deviate from the center of the rotor so that the magnetic steel of the positioning pole is closer to the center of the rotor, the center angle of the magnetic steel of the positioning pole is 52 degrees, and the center angle of the remaining magnetic poles is 44 degrees);

[0018] In the figure: 100 - positioning magnetic pole. DETAILED DESCRIPTION

[0019] As shown in the figure, an asymmetric and eccentric pole permanent magnet motor is provided, wherein each pole of the motor rotor is a fan-shaped magnetic steel part, one of which is a positioning pole used to obtain the angular displacement of the motor; the central angle of the fan-shaped ring of the positioning pole is larger than that of the other poles; the inner diameter or outer diameter of the positioning pole is different from that of the other poles, so as to reduce the cogging torque at the positioning pole when the rotor rotates.

[0020] The magnetic inductor at the stator is a magnetic sensor; the positioning magnetic pole at the rotor matches the detection surface of the magnetic sensor, and the magnetic sensor is triggered when the positioning magnetic pole rotates to be adjacent to the magnetic sensor.

[0021] A positioning protrusion is provided at the lower end surface of the positioning magnetic pole, and the positioning protrusion is embedded in the installation groove of the rotor punching sheet.

[0022] Except for the positioning pole, the center angles of the other poles of the motor rotor are the same, all , let n be the number of poles of the motor, and the center angle of the locating magnetic pole is ,but (360- ) / (n-1).

[0023] Locate the center angle of the magnetic pole Size range, is the central angle of other magnetic poles 1.1 to 1.2 times of.

[0024] When the positioning pole only differs from other poles in outer diameter and its inner diameter is the same as other poles, the thickness at the center axis of the positioning pole is the same as that of other poles. The outer diameter of the magnet is eccentric so that the thickness of the magnet gradually decreases from the middle to both sides, thereby reducing the torque by reducing the weight of the magnet.

[0025] When the inner diameter and outer diameter of the positioning pole are different from those of other poles, let R be the radius of the rotor core punching sheet. If the thickness of the positioning pole magnetic steel part remains unchanged at all locations, the thickness of the magnetic steel part is the same as that of other magnetic steel parts. The distance that the inner diameter and outer diameter of the magnetic steel part deviate from the center of the rotor, that is, the eccentricity d=8%~12%R, makes the magnetic steel part closer to the center of the rotor, and reduces the torque by reducing the centrifugal force of the magnetic steel.

[0026] The permanent magnet motor includes a casing, a stator, and a rotor. The stator and the rotor are both formed by stacking a number of punching sheets. The stator is arranged around the rotor. A coil is wound around the stator and a magnetic sensitive sensor is installed. An asymmetric and eccentric magnetic steel is installed on the rotor. A front cover and a rear cover are respectively arranged at the front and rear ends of the casing.

[0027] The motor in this example is an 8-pole motor. Figure 2 As shown, a number of magnets are arranged on the rotor, wherein the angle γ occupied by the width of one of the magnets (the positioning magnetic pole, i.e., the asymmetric pole, the magnet number is 1 in the figure) is larger than the angle occupied by the other magnets (the angle occupied is 1.1 to 1.2 times the average angle Υ), and at the same time, the magnet has a protrusion at the bottom, which is embedded and positioned with the groove on the rotor punching sheet. The outer diameter of the magnet deviates from the center of the rotor by a certain distance d (d=8% to 12%R, R is the radius of the rotor core punching sheet), and the thickness of the magnet 1 is high in the middle and gradually decreases along both sides;

[0028] like Figure 3 As shown, a number of magnets are arranged on the rotor, wherein the angle γ occupied by the width of one of the magnets (the positioning magnetic pole, i.e., the asymmetric pole, the magnet number is 1 in the figure) is larger than the angle occupied by the other magnets (the angle occupied is 1.1-1.2 times of the average angle Υ), and at the same time, the magnet has a protrusion at the bottom, which is embedded and positioned with the groove on the rotor punching sheet, and the inner diameter and outer diameter of the magnet are both deviated from the center of the rotor by a certain distance d (d=8%-12%R, R is the radius of the rotor core punching sheet), that is, the thickness of the magnet 1 is the same as that of the other magnets (numbers 2-8), and the inner and outer diameters of the magnet are different from those of the other magnets; Figure 3 The inner and outer diameters of the magnetic poles deviate from the center of the rotor by a certain distance d (d=8%~12%R, R is the radius of the rotor core punching sheet). Through the design of the present invention, the asymmetric magnetic steel is combined with the magnetic sensor arranged on the stator (low cost and easy installation), which can easily obtain the angular displacement of the motor and improve the control accuracy.

[0029] Since the asymmetric magnet increases the cogging torque, this example reduces the cogging torque by deviating the asymmetric magnet from the rotor center by a certain distance. Ultimately, the purpose of improving control accuracy and reducing cogging torque is achieved. This design can reduce the motor volume (total length) and motor cost while ensuring control accuracy.

[0030] Based on this premise, this example adds a partition and diffuser structure to directly and effectively transfer the heat inside the generator through the diffuser to the surface of the casing for heat dissipation.

Claims

1. An asymmetric and eccentric pole permanent magnet motor, characterized in that: Each magnetic pole of the motor rotor is a fan-shaped magnetic steel part, one of which is a positioning magnetic pole used to obtain the angular displacement of the motor; the central angle of the fan-shaped ring of the positioning magnetic pole is larger than that of other magnetic poles; the inner diameter or outer diameter of the positioning magnetic pole is different from that of other magnetic poles, so as to reduce the tooth slot torque at the positioning magnetic pole when the rotor rotates.

2. The asymmetric and eccentric pole permanent magnet motor according to claim 1, characterized in that: The magnetic inductor at the stator of the motor is a magnetic sensor; the positioning magnetic pole at the rotor matches the detection surface of the magnetic sensor, and the magnetic sensor is triggered when the positioning magnetic pole rotates to be adjacent to the magnetic sensor.

3. The asymmetric and eccentric pole permanent magnet motor according to claim 1, characterized in that: A positioning protrusion is provided at the lower end surface of the positioning magnetic pole, and the positioning protrusion is embedded in the installation groove of the rotor punching sheet.

4. The asymmetric and eccentric pole permanent magnet motor according to claim 1, characterized in that: Except for the positioning pole, the center angles of the other poles of the motor rotor are the same, all , let n be the number of poles of the motor, and the center angle of the locating magnetic pole is ,but (360- ) / (n-1).

5. The asymmetric and eccentric pole permanent magnet motor according to claim 4, characterized in that: Locate the center angle of the magnetic pole Size range, is the central angle of other magnetic poles 1.1 to 1.2 times of.

6. The asymmetric and eccentric pole permanent magnet motor according to claim 5, characterized in that: When the positioning pole differs from other poles only in outer diameter and has the same inner diameter as other poles, the thickness at the center axis of the positioning pole is the same as other poles, and the outer diameter of the magnetic steel is eccentric so that the thickness of the magnetic steel gradually decreases from the middle to both sides.

7. The asymmetric and eccentric pole permanent magnet motor according to claim 5, characterized in that: When the inner diameter and outer diameter of the positioning pole are different from those of other poles, let R be the radius of the rotor core punching sheet. If the thickness of the positioning pole magnetic steel part remains unchanged at all locations, the thickness of the magnetic steel part is the same as that of other magnetic steel parts. The distance that the inner diameter and outer diameter of the magnetic steel part deviate from the center of the rotor, that is, the eccentricity d=8%~12%R, makes the magnetic steel part closer to the center of the rotor.

8. The asymmetric and eccentric pole permanent magnet motor according to claim 2, characterized in that: The permanent magnet motor includes a casing, a stator, and a rotor. The stator and the rotor are both formed by stacking a number of punching sheets. The stator is arranged around the rotor. A coil is wound around the stator and a magnetic sensitive sensor is installed. An asymmetric and eccentric magnetic steel is installed on the rotor. A front cover and a rear cover are respectively arranged at the front and rear ends of the casing.

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