JP2006238679A - Single-phase permanent magnet motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-efficiency and low-cost single-phase permanent magnet synchronous motor, capable of directly rotating by a single-phase AC power source, without the need for external components, such as capacitors. <P>SOLUTION: A rotor is arranged, facing via air gaps in the inner sides of a stator provided with a plurality of magnetic pole teeth segments, and stator coils are wound, in such a manner that they are wound over respective magnetic pole teeth segments, or wound over a stator core connecting the plurality of magnetic pole teeth segments. The rotor serves as a permanent magnet rotor, provided alternately with N/S poles at equal pitches on the outer circumference so as to maintain the same polarity in the axial direction. The radial length, from the center of rotation axis to each magnetic pole teeth segment, becomes minimal, at a position where it does not coincide with the center of tooth width of each magnetic pole teeth segment, and roughly speaking, it gradually increases toward the same circumferential direction for each magnetic pole teeth segment. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a permanent magnet type single-phase synchronous motor that does not require an external component such as a capacitor and can be rotated only by being connected to a single-phase AC power supply, and more particularly to a stator core and a permanent magnet type rotor structure.

  Conventionally, as a motor that can be rotated only by connecting to a single-phase AC power source without requiring external parts, for example, a coiled coil type single-phase induction motor as shown in FIG. 5 is generally employed. FIG. 5A is a configuration diagram of the main part of a four-pole, coiled-coil single-phase induction motor. The stator core 21 has a tooth-coiling coil 130 at the tooth tip, and four magnetic pole teeth 30. The stator coil 10 is wound around and terminal processing such as lead wire connection is performed. FIG. 5B shows a configuration diagram of a two-pole bearer coil type single-phase induction motor, and two magnetic pole teeth The stator coil 10 is wound around the stator core 21 that connects the portions 30, and in both cases, the radial length of the air gap 88 with the cage rotor 180 is equal in the circumferential direction. It is configured.

  In the conventional decoy coil type single-phase induction motor as shown in FIGS. 5 (a) and 5 (b), the starting torque is small, and the decoy coil 130 has a current during operation other than the start-up. There is a problem that the efficiency is poor because of flowing.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain a high-efficiency and low-cost permanent magnet type single-phase motor.

  In order to achieve the above-described object, a single-phase motor according to the present invention is fixed by winding a stator coil so as to be wound around each magnetic pole tooth part or around a stator core connecting a plurality of magnetic pole tooth parts. On the inner side of the rotor, a permanent magnet type rotor having N and S poles alternately arranged at the same pitch on the outer periphery and having the same polarity in the axial direction is arranged, and from the center of the rotating shaft to each magnetic pole tooth portion. The radial length is minimized at a position that does not coincide with the circumferential tooth width center of each magnetic pole tooth portion, and is generally formed so as to gradually increase in the same circumferential direction for each magnetic pole tooth portion.

  In the single-phase motor according to the next invention, each magnetic pole of the permanent magnet type rotor facing the stator is formed so that the radial length of the air gap is reduced in the vicinity of the center in the circumferential direction. .

  The single-phase motor according to the next invention operates at the rated voltage by applying a voltage higher than a predetermined rated voltage at the time of start-up and then decreasing the voltage gradually or stepwise.

  The single-phase motor according to the next invention operates at a predetermined rated frequency after the power supply frequency is gradually increased or increased stepwise at the time of startup.

  According to the single-phase motor according to the present invention, the radial length from the center of the rotating shaft to each magnetic pole tooth portion is minimized at a position that does not coincide with the circumferential tooth width center of each magnetic pole tooth portion. In addition, a permanent magnet type single-phase synchronous motor that can be directly rotated by a single-phase AC power source without the need for external components such as a capacitor can be obtained. Since the single-phase motor according to the present invention is a synchronous motor using a permanent magnet type rotor, there is no loss due to the secondary current, and the conventional equipment is used for the stator core manufacturing and coil winding work. Therefore, a low-cost and highly efficient single-phase motor can be obtained.

  According to the single-phase motor according to the next invention, the shape of each magnetic pole of the permanent magnet type rotor is formed so that the radial length of the air gap is reduced in the vicinity of the center in the circumferential direction. Since the magnetic saliency can be manifested, the starting characteristics of the single-phase motor can be improved.

  According to the single-phase motor of the next invention, by applying a voltage higher than a predetermined rated voltage at the time of start-up, it becomes possible to easily perform synchronous pull-in even for applications with large load torque, and the start-up characteristics of the single-phase motor can be improved. Further improvement can be achieved.

  According to the single-phase motor according to the next invention, the frequency of the power supply is gradually increased or increased in steps at the time of start-up, so that synchronous pull-in can be easily performed even for applications with large load torque. Can be further improved. In addition, the single-phase motor can be operated at a variable speed by changing the frequency of the power source.

  Embodiments of a single-phase motor according to the present invention will be described below in detail with reference to the accompanying drawings.

  FIG. 1 is a configuration diagram of a main part in a direction perpendicular to the axis showing an example applied to a two-pole motor as a first embodiment of a single-phase motor according to the present invention, and shows a stator coil 10, a lead wire 13, and a stator. 20, a permanent magnet type rotor 80, a rotating shaft 90, and the like.

  The stator 20 includes a stator coil 10 and a stator core 21, and magnetic pole teeth 30 and 31 are formed so as to face the permanent magnet rotor 80 with an air gap 88 therebetween.

  The stator coil 10 is wound so as to be wound around the stator core 21 connecting the two magnetic pole tooth portions 30 and 31 using a magnet wire, subjected to appropriate insulation treatment, and single-phased by the lead wire 13. Connected to AC power source.

  As shown in FIG. 1, the tooth tip shape of the magnetic pole tooth portions 30 and 31 is formed in an arc shape having a center that does not coincide with the center of the rotating shaft 90, and therefore does not coincide with the center of the tooth width in the circumferential direction. -The length in the radial direction from the center of the rotating shaft 90 is the smallest at the portion 72, and is formed so as to gradually increase in the same circumferential direction. As a result, the radial length of the air gap 88 is also minimized at the portions 71 and 72, and is gradually increased in the same circumferential direction for each magnetic pole tooth portion.

  In the permanent magnet type rotor 80, for example, permanent magnets 82 constituting each magnetic pole are arranged on the outer periphery of a rotor core 81 integrated with a rotating shaft 90 processed into a predetermined shape, and the magnetic pole teeth of the stator 20. It is rotatably supported by a bearing member (not shown) through 30 and 31 and an air gap 88. Note that the rotor core 81 may be configured using another magnetic member without being integrated with the rotating shaft 90.

  FIG. 1 shows the positional relationship between the tooth tip shapes of the magnetic pole tooth portions 30 and 31 when the power is turned off and the permanent magnets 82 arranged on the outer periphery of the permanent magnet rotor 80. The magnet center (circumferential center) of each magnetic pole composed of the permanent magnet 82 and the magnetic pole tooth portion 71 where the radial length of the air gap 88 is minimized so that the permeance of the magnetic circuit is maximized when stopped. The rotating shaft 90 stops at a position where the portions 72 coincide. As a result, a large torque can be generated by the main magnetic flux of the stator coil 10 at the time of start-up, and the permanent magnet type rotor 80 is drawn to the synchronous speed, and the magnetic pole teeth 30 and 31 and the permanent magnet type rotor 80 are rotated during the rotation. Since the so-called dead center where the torque becomes zero can be avoided by the gradual increase effect of the air gap 88 between them, the rotation can be continued. When the portions 71 and 72 are arc-shaped around the rotation shaft 90, the circumferential center of the arc is formed so as not to coincide with the circumferential tooth width center of the magnetic pole tooth portions 30 and 31. It can be made to act similarly.

  According to the configuration as described above, there is no loss due to the secondary current because of the synchronous motor using the permanent magnet type rotor, and the conventional equipment is used for the stator core manufacturing and coil winding work. Therefore, a low-cost and highly efficient single-phase motor can be obtained.

  FIG. 2 shows a second embodiment of the single-phase motor according to the present invention. In a two-pole motor, each magnetic pole of the permanent magnet type rotor 80 has a small radial length of the air gap 88 in the vicinity of the center in the circumferential direction. It is a block diagram in the direction perpendicular to the axis showing an example formed in this way, and other parts are omitted in the drawing.

  In FIG. 2A, the minute convex portion 73 is formed on the outer peripheral surface so that the radial length of the air gap 88 (not shown) is reduced in the vicinity of the center in the circumferential direction of each magnetic pole constituted by the permanent magnet 82. Is formed. In FIG. 2B, each magnetic pole constituted by the permanent magnet 82 is formed to be convex outward, and the radial length of the air gap 88 is the smallest in the vicinity 73 of the center in the circumferential direction. The air gap 88 is formed such that the radial length of the air gap 88 gradually increases between the poles.

  According to the configuration as described above, since the magnetic saliency can be revealed in the vicinity of the magnet center of each magnetic pole, the rotating shaft 90 can be reliably stopped at a predetermined position when the power is OFF. The starting characteristics of the single phase motor can be improved. The shape of these magnetic poles can be easily formed by using a plastic magnet or a bond magnet.

  FIG. 3 shows an example of a single-phase motor according to a third embodiment of the present invention, in which a voltage higher than a predetermined rated voltage is applied at start-up, and then the voltage is gradually decreased or stepwise reduced to operate at the rated voltage. In FIG. 3A, the power supply is turned on and synchronous pull-in is performed by applying an overvoltage, and the voltage is gradually decreased to a rated voltage V (v) after a predetermined time t (sec). In FIG. 3B, the power supply is turned on to perform synchronous pull-in by applying an overvoltage, and the voltage is decreased stepwise so that the rated voltage V (v) is reached after a predetermined time t (sec).

  According to the starting method as described above, the synchronous pull-in can be easily performed even for an application with a large load torque, and the starting characteristics of the single-phase motor can be improved.

  FIG. 4 shows a fourth embodiment of the single-phase motor according to the present invention, in which the power supply frequency is gradually increased or increased stepwise at the time of start-up and then operated at a predetermined rated frequency. In FIG. 4A, the power is turned on to perform synchronous pull-in at a low speed, and after a predetermined time t (sec), the frequency is gradually increased to the rated frequency f (Hz). FIG. 4B shows the case where the power is turned on to perform synchronous pull-in at a low speed, and the voltage is increased stepwise so that the rated frequency f (Hz) is obtained after a predetermined time t (sec).

  Even with the startup method as described above, the synchronous pull-in can be easily performed for an application with a large load torque, and the startup characteristics of the single phase motor can be improved. In addition, the single-phase motor can be operated at a variable speed by changing the frequency of the power source.

  The above-described embodiment is mainly applied to the present invention when the number of poles of the single-phase motor is two. However, the single-phase motor according to the present invention is also effective for cases having other pole numbers. Moreover, as the permanent magnet type rotor according to the present invention, an example using a ring-shaped permanent magnet was shown, but besides this, a structure in which a segment-shaped permanent magnet is fixed to the surface of the rotor core by bonding or the like, Alternatively, a structure embedded in the rotor core can be adopted. Furthermore, an outer rotor type single-phase motor structure may be used.

  The single-phase motor according to the present invention can be used as a fan motor for home appliances or a small fan motor because it can be operated with high efficiency only by being connected to a single-phase AC power source. Further, since uniform speed operation with a single single-phase AC power supply is possible, it can also be used for textile machines and the like.

FIG. 3 is a configuration diagram of the single-phase motor in the first embodiment in a direction perpendicular to the axis. FIG. 6 is a configuration diagram in the direction perpendicular to the axis of a permanent magnet rotor according to a second embodiment. It is the relationship between the power supply voltage at the time of starting in Example 3, and time. It is the relationship between the power supply frequency at the time of starting in Example 4, and time. 1 shows a conventional coiled coil type single-phase induction motor, in which (a) is a configuration diagram of a four-pole machine, and (b) is a configuration diagram of a two-pole machine.

Explanation of symbols

  10 Stator Coil, 13 Lead Wire, 20 Stator, 21 Stator Core, 30/31 Magnetic Tooth Portion, 71/72 The portion where the radial length of the air gap formed in the magnetic pole tooth portion is minimized, 73 Magnet Convex part formed in the vicinity of the center, 80 permanent magnet type rotor, 81 rotor core, 82 permanent magnet, 88 air gap, 90 rotating shaft, 130 decoy coil, 180 cage rotor

Claims (4)

  A rotor facing the air gap is arranged inside a stator having a plurality of magnetic pole tooth portions, and a stator coil is wound around each magnetic pole tooth portion, or a plurality of the magnetic pole tooth portions are arranged. In the single-phase motor wound so as to be wound around the stator core to be connected, the rotor is a permanent magnet type rotor provided with N and S poles alternately on the outer periphery so as to have the same polarity in the axial direction at an equal pitch. The radial length from the center of the rotating shaft to each magnetic pole tooth is minimum at a position that does not coincide with the circumferential tooth width center of each magnetic pole tooth, and is generally around each magnetic pole tooth. A permanent magnet type single-phase motor, characterized by being formed so as to gradually increase in the same direction.   2. The magnetic poles of the permanent magnet type rotor facing the stator are formed so that the radial length of the air gap is reduced in the vicinity of the center in the circumferential direction. The permanent magnet type single-phase motor described.   3. The permanent operation according to claim 1, wherein a voltage higher than a predetermined rated voltage is applied at start-up, and then the voltage is gradually decreased or decreased stepwise to operate at the rated voltage. 4. Magnet type single phase motor.   The permanent magnet single-phase motor according to any one of claims 1 to 3, wherein the permanent magnet type single-phase motor is operated at a predetermined rated frequency after the power supply frequency is gradually increased or stepwise increased at startup.

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