JP2009055750A - Claw pole type pm motor and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multi-phase claw pole type PM motor in which a rare-earth magnet is used, and which produces high output with a stator structure causing no magnetic saturation. <P>SOLUTION: A soft magnetic steel plate excellent in magnetic characteristics is folded, laminated, annealed and molded to form a stator. A first stator and a second stator are punched out from the soft magnetic steel plate, and subjected to annealing in order to remove magnetic distortion due to processing after folding a claw magnetic pole portion 10. Moreover, the rare-earth magnet having high residual magnetic flux density, even if used, is laminated in order to secure the thickness required for a claw magnetic pole or the like so as to cause no magnetic saturation, and the stator is formed. Furthermore, in order to reduce the contact magnetic resistance of the respective components constituting a magnetic circuit as much as possible, a contact area is increased. Moreover, in order to improve productivity, a first stator iron core 9A and a second stator iron core 9B are molded to facilitate deformation and accuracy securement of the claw magnetic pole. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a multi-phase PM claw pole type motor used in the fields of industry, home appliances, automobiles and the like, and more specifically, a rotor having magnets in which NS poles are alternately arranged on the outer peripheral surface, a magnet and an air PM claw pole type comprising a stator core having trapezoidal claw magnetic poles alternately facing each other through a gap, and an annular coil provided inside each stator core for magnetizing the claw magnetic poles This is related to higher output of the motor.

  Patent Document 1 proposes to use a rare earth magnet having a high residual magnetic flux density for increasing the torque of a PM type stepping motor.

In general rotating electrical machines, in order to increase the winding rate of windings and improve the utilization rate of magnetic flux, for example, as disclosed in Patent Document 2, a PM claw pole type iron core laminated with soft magnetic steel plates is used. A structure comprising: has been proposed.

Patent Document 3 proposes a PM claw pole type motor using a dust core material.

Japanese Patent No. 3895712 JP 2003-333777 A Japanese Patent Application No. 2006-250207

  With the increase in torque of the PM type stepping motor according to Patent Document 1, there is a lack of consideration for the claw magnetic pole portion formed by bending a soft magnetic steel plate. In practice, if a rare earth magnet with a high residual magnetic flux density is used, the stator such as the claw magnetic poles is insufficient in thickness, causing magnetic saturation in the stator and making it impossible to utilize the magnetic flux of the magnet. In addition, the magnetic distortion caused by the bending process occurs in the bent part of the claw magnetic pole, the magnetic permeability is remarkably lowered, and magnetic saturation also occurs in this part. For PM type stepping motors, few motors use rare earth magnets with high residual magnetic flux density.

  In Patent Document 2, an improvement is made by adopting a laminated structure using thin plates with increased eddy currents caused by magnetostriction caused by sheet metal pressing of the stator. Because the soft magnetic steel plate is composed only of laminates, only simple claw magnetic poles can be obtained. As a result, partial magnetic saturation of the stator core and magnetic force composed of permanent magnets and stators can be obtained. There are many leakage fluxes in the circuit section, and there is a problem that an expected high efficiency motor cannot be obtained.

  In Patent Document 3, a claw magnetic pole material formed by compression molding magnetic powder is used to form a claw magnetic pole having a complicated shape, thereby forming a claw magnetic pole having a shape that is not magnetically saturated with machining magnetostriction. By using a rare earth magnet with a high residual magnetic flux density, it is possible to manufacture a high-power PM claw pole type motor.

  However, in order to form a claw magnetic pole with a dust core material, there are many restrictions on the shape that can be formed. For example, when the outer diameter of the stator is reduced, the radial thickness of the claw magnetic pole needs to be reduced. However, there is a limit to product strength in compression molding of magnetic powder, and when the outer diameter of the stator is 60 mm or less, the thickness of the claw magnetic poles becomes thin and it is difficult to mold.

  The object of the present invention is to form a claw pole that does not saturate with machining magnetostriction even when a rare earth magnet with a high residual magnetic flux density is used without being restricted by the outer diameter of the stator, and has high output and high efficiency. Is to provide a multi-phase PM claw pole type motor at low cost.

  In order to achieve the above object, the present invention forms a stator by bending, laminating, annealing and molding a soft magnetic steel sheet having excellent magnetic properties. The first stator and the second stator are punched from the soft magnetic steel plate, the claw pole part is bent, and annealing treatment is performed to remove the magnetic distortion caused by the processing. In addition, a stator is formed by laminating in order to secure a necessary thickness for the claw poles and the like so that magnetic saturation does not occur even when a rare earth magnet having a high residual magnetic flux density is used. Furthermore, the contact area of each component is increased in order to reduce the contact magnetic resistance of each component constituting the magnetic circuit as much as possible. In addition, in order to improve productivity, the first stator core and the second stator core are molded to facilitate deformation of the claw magnetic poles and ensuring accuracy.

According to the present invention, a conventional soft magnetic steel plate having excellent magnetic characteristics can be combined with a rare earth magnet having a high residual magnetic flux density, and a motor having the following excellent features can be configured.
(1) The magnetic saturation problem is solved by the number of laminated soft magnetic steel sheets, and a rare earth magnet having a high residual magnetic flux density can be used, so that the output of the motor can be increased.
(2) By performing an annealing process to remove the magnetic distortion caused by bending the claw pole part, the permeability can be improved and the motor output can be increased.
(3) Claw magnetic poles are easily deformed by annealing, but resin molding improves the strength and dimensional accuracy, and the air gap between the magnet and claw magnetic pole can be secured appropriately, enabling higher motor output. Become. In addition, the tip length of the claw poles of the laminated stator core is made longer than that of the claw poles facing the magnet, so that the claw pole presser is reinforced with resin and the attractive repulsion force is increased. Deformation to the magnet side can be suppressed.
(4) The first stator core and the second stator core can be configured in the same shape, can be processed with the same mold, and cost can be reduced.
(6) It is possible to increase the contact area between the outer periphery of the outer yoke and the ring yoke in the first stator and the second stator, and the magnetic resistance of the magnetic circuit can be reduced. High output is possible.

  Embodiments of the present invention will be described below with reference to the drawings.

A first embodiment of a three-phase PM claw pole type motor according to the present invention will be described with reference to FIGS.
FIG. 1 shows the structure of a three-phase PM claw pole type motor according to the present invention. The motor includes a rotor 2, a stator 5 installed concentrically with a small gap in the circumferential direction with respect to the rotor 2, a stator frame 7 that supports the stator 5, and the stator frame 7 The rotary shaft 1 is rotatably supported at both ends via bearings 8A and 8B.

The rotor 2 is composed of a rotor core 3 formed concentrically with the rotary shaft 1 and a magnet 4 fixed on the outer periphery and magnetized in multiple poles, and the stator 5 is composed of a stator core. 6U, 6V, 6W and annular windings 13U, 13V, 13W sandwiched between these stator cores 6U, 6V, 6W. The stator cores 6U, 6V, and 6W are supported by the stator frame 7, and the rotary shaft 1 is rotatably supported at both ends of the stator frame 7 through bearings 8A and 8B.

  FIG. 2 shows details of a part of the shape of the stator core. The stator cores 6U, 6V, and 6W are composed of a first stator core 9A and a second stator core 9B, and the first stator core 9A and the second stator core 9B have shafts. From the claw magnetic pole 10 extending in the direction and facing the rotor 2 with a minute gap, the radial yoke portion 11 extending perpendicularly from the claw magnetic pole 10 to the outer diameter side, and the radial yoke portion 11 It is comprised with the outer periphery side yoke 12 extended in the same direction as the said nail | claw part 10. As shown in FIG. FIG. 3 shows that the second stator core 9B in the first stator core 9A is integrally formed by resin molding, 21 is a resin filling portion, and 13 is a partial shape of a stator set with an annular winding. It shows the details.

  4 to 8 are diagrams showing the processing steps of the stator assembly. FIG. 4 shows one stator core formed by punching a thin soft magnetic steel plate with a press and bending the claw magnetic pole portion 10. FIG. 5 shows a process of laminating bent soft magnetic steel sheets. The number of laminated layers is set so that the stator iron core such as the claw magnetic pole 10 does not cause magnetic saturation depending on the residual magnetic flux density of the magnet 4 to be used. Soft magnetic steel sheets are accompanied by magnetostriction due to pressing and bending, and magnetic properties such as permeability are greatly deteriorated. If it is incorporated in the motor in this state, it will cause a large iron loss, resulting in higher efficiency and higher temperature rise, resulting in lower motor output.

  In order to remove this processing magnetostriction, it is possible to restore the magnetic properties before processing by putting in an annealing furnace at 800 to 900 ° C. and performing annealing. However, annealing makes the stator core harder and deforms more easily. In particular, the pawl magnetic pole 10 facing the magnet 4 receives an attractive repulsive force and needs mechanical reinforcement.

  FIG. 6 relates to claim 2. Resin molding of the first stator core and the second stator core together for the purpose of securing the claws magnetic pole 10 and securing the combination accuracy of the first stator core and the second stator core. It is a figure which shows the process to do. The hatched portion in the figure indicates a portion filled with the resin 21. The stator core is covered with resin except for the claw magnetic pole portion 10. The molding resin can be molded in a short time by injection molding if a thermoplastic material is used.

  In FIG. 7, the motor winding 13 is wound in a space formed by insulation between the first stator core and the second stator core by resin molding.

  FIG. 8 shows a state in which a ring-shaped yoke 22 is wound between the outer peripheral yokes 12 of the first stator core and the second stator core, and this shape is a stator set for one phase of the motor. The ring-shaped yoke 22 is partially provided with a cutout portion for providing a lead wire for the motor winding.

  FIGS. 4 to 8 show the manufacturing process of the stator assembly for one phase. In the resin molding process of FIG. It is possible to reduce the manufacturing time by molding and winding the motor windings for the number of phases at the same time.

  FIG. 9 is an enlarged view of the pressed surface of the tip 20 of the claw pole 10 of FIG. In the figure, the length of the tip of the claw pole can be reinforced with resin by increasing the length of the tip of the claw pole of the stator core from the one facing the magnet to the length of the claw pole. In this way, it is possible to suppress the deformation to the magnet side where the attractive repulsive force is generated. As a result, vibration as a motor can be greatly reduced. It is also effective to provide minute irregularities on the outer periphery of the claw magnetic pole 10 in order to further increase the deformation suppressing effect.

  In order to apply to a motor with higher output, as shown in FIG. 10, the tip of the claw magnetic pole portion 10 of the stator core 9 is bent in the motor outer diameter direction to form a holding portion 26. The surface of the pressing portion 26 is covered with resin at the time of molding, and the stacked claw magnetic poles 10 can suppress deformation even if a large attractive repulsive force with the magnet 4 is generated.

  FIG. 11 is a development view of the ring-shaped yoke 22, which is assembled by partially punching a linear material and winding it around the outer yoke portion 12 of the stator core. The ring-shaped yoke 22 is provided with a convex portion 27, and the outer peripheral side yoke portion 12 of the stator core is provided with a concave portion 28. The contact surface between the outer peripheral side yoke portion 12 and the ring-shaped yoke 22 is uneven. Thus, it is possible to suppress the increase in the magnetic resistance of the motor magnetic circuit by increasing the contact area.

A characteristic comparison between the laminated PM claw pole type motor of the present invention and a conventional slot type brushless DC motor was carried out with the following general specifications. A conventional three-phase slot type brushless DC motor has a stator outer diameter of Φ60 mm, 14 salient poles, a laminated thickness of 50 mm, and a stator thickness of about 60 mm including the coil end of the winding. The magnet has a residual magnetic flux density of 0.65 Tesla and an outer diameter of 12 poles of Φ29 mm.
In the laminated PM claw pole type motor to be compared, the magnet has the same outer diameter as that of the slot type motor, the number of magnetic poles of the magnet is 14, the number of claw magnetic poles is 14, and the stator assembly is laminated in the motor axial direction. It is composed.
As the stator core material, four laminated 0.5 mm silicon steel plates were measured and compared with motor constants expressing the goodness of the motor. The motor constant Tm can be expressed as Tm = Ke / √R where the back electromotive force constant Ke and the motor winding resistance R are given. In other words, an evaluation equivalent to the ratio of motor copper loss to output torque is possible, and the larger the motor constant, the better.
As a result of trial manufacture, Tm = 0.18 (VS / √Ω) was obtained with the laminated PM claw pole type motor, compared with Tm = 0.14 (VS / √Ω) of the conventional slot type motor. In other words, by using a laminated PM claw pole type motor, the motor output could be increased by 28% with the same motor size.

  According to the present invention, by developing a conventional processing technology, a soft magnetic steel plate with excellent magnetic properties can be combined with a rare earth magnet having a high residual magnetic flux density, and the output of a PM claw pole motor can be increased. When applied to a brushless DC motor, the conventional slot type motor can be reduced in size and increased in output. In the embodiment, a three-phase PM claw pole type motor is shown, but the present invention can be applied not only to three phases but also to all multiphase motors having two or more phases.

Structure diagram of PM claw pole type motor of the present invention The figure which shows the shape of a part in the stator core of this invention The figure which shows the shape of a part in the stator core of this invention The figure which shows the manufacturing process of the stator group of this invention The figure which shows the manufacturing process of the stator group of this invention The figure which shows the manufacturing process of the stator group of this invention The figure which shows the manufacturing process of the stator group of this invention The figure which shows the manufacturing process of the stator group of this invention Enlarged view of the pressed surface of the claw pole tip The figure which shows the shape of a part in the stator core of this invention Development of ring-shaped yoke

Explanation of symbols

1: Motor shaft 2: Rotor 3: Rotor core 4: Magnet
5: Stator assembly 6: Stator iron core 7: Stator frame 8: Bearing 9: First stator iron core 9B: Second stator iron core 10: Claw magnetic pole 11: Radial yoke part 12: Outer side joint Iron 13: Annular winding 20: Claw pole tip 21: Resin filling part 22: Ring-shaped yoke 27: Convex part 28: Concave part

Claims (9)

A claw portion extending in the axial direction and having a magnetic pole face facing the rotor with a minute gap, a radial yoke portion extending from the claw portion to the outer diameter side, and the claw portion from the radial yoke portion A first stator core and a second stator core that form a plurality of claw magnetic poles with outer yokes extending in the same direction as
The plurality of claw magnetic poles are alternately arranged in the circumferential direction, and the front end of the claw portion of the claw magnetic pole in the first stator core and the front end of the claw portion of the claw magnetic pole in the second stator core are nested. And forming a stator core by sandwiching an annular coil between the claw magnetic poles of the stator core, and stacking a required number of stator sets in the motor axial direction, In a multi-phase PM claw pole motor in which a claw pole and an air gap are provided and a facing rare earth magnet is disposed, the first stator core and the second stator core are punched out of a soft magnetic steel plate to A PM claw pole type motor characterized in that it is bent at a substantially right angle and annealed, and a required number of sheets are laminated in the motor axial direction.   The first stator core and the second stator core are arranged so that the tip of the claw portion of the claw magnetic pole is nested, so that the portion that contacts the annular coil and the claw magnetic pole are insulated. The first stator core and the second stator core are integrally molded with a resin molding material having a property to form a stator sub-set, and winding is performed from the outer periphery of the stator sub-set. The PM claw pole type motor according to claim 1.   The first stator iron core and the second stator iron core are arranged so that the tip of the claw portion of the claw magnetic pole is nested, and an annular coil insulated by the claw magnetic pole is sandwiched between the resin molded material The PM claw pole type motor according to claim 1, wherein the first stator core and the second stator core are integrally formed.   The tip of the claw magnetic pole portion of the laminated stator core is higher in height than the claw magnetic pole on the outer diameter side than the inner claw magnetic pole facing the magnet, The first stator core and the second stator core are integrally formed of a resin molding material having an insulating property in order to form a second stator core and insulate between the claw magnetic poles. Item 4. The PM claw pole type motor according to items 1 to 3.   The PM claw pole type motor according to claim 4, wherein minute irregularities are provided on an outer periphery of the claw magnetic pole.   2. A structure in which a step is provided at the tip of the claw magnetic pole, and the step is a surface of the step at the tip during resin molding, and the surface facing the magnet is covered with the step by resin molding. 3. The PM claw pole type motor described in 3.   The first stator core and the second stator core are provided with a recess in the outer periphery of the outer yoke, and the ring yoke having a protrusion in the motor axial direction is connected to the first stator core and the second stator core. 4. The PM claw pole type motor according to claim 1, wherein the PM claw pole type motor is inserted between the outer peripheral side yokes of the two stator cores so that the irregularities are nested.   In Claim 1, it arrange | positions so that the front-end | tip of the said nail | claw part of the claw magnetic pole in the 2nd stator iron core in said 1st stator iron core may be nested, and the part which contact | connects an annular coil, and a claw magnetic pole between To insulate, the first stator iron core and the second stator iron core for the required number of motor phases are molded integrally with a resin molded material with insulation to form a laminated stator sub-assembly, and this laminated fixing A PM claw pole type motor that is wound from the outer periphery of a child sub-assembly. A claw portion extending in the axial direction and having a magnetic pole face facing the rotor with a minute gap, a radial yoke portion extending from the claw portion to the outer diameter side, and the claw portion from the radial yoke portion A first stator core and a second stator core that form a plurality of claw magnetic poles with outer yokes extending in the same direction as
The plurality of claw magnetic poles are alternately arranged in the circumferential direction, and the tip of the claw pole of the claw magnetic pole in the first stator core and the tip of the claw pole of the claw magnetic pole in the second stator core are nested. The stator core is formed so as to form a stator assembly by sandwiching an annular coil between the claw magnetic poles of the stator core, and a required number of the stator assemblies are stacked in the motor axial direction. In a multi-phase PM claw pole motor in which a magnetic pole and an air gap are provided and an opposing rare earth magnet is disposed, the first stator core and the second stator core are punched out of a soft magnetic steel plate, and the claw pole part is almost Bend at right angles, and after annealing, stack the required number in the motor axis direction and place the first stator core and second stator core so that the tips of the claw poles are nested. Then, fill it with an insulating resin molding material. The first stator core and the PM claw pole type motor manufacturing method, which comprises forming by resin molding integrally with the second stator core.

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