JP2004248363A - Claw pole motor - Google Patents

Abstract

An object of the present invention is to reduce cogging torque, improve magnetic characteristics, reduce the number of types of components, and reduce costs.
A field element (20) in which field poles (21) are alternately arranged in the circumferential direction at equal intervals and alternately, and claw poles (13, 13 ') arranged at equal pitches opposite to the field pole (21). A phase unit composed of a pair of magnetic members 11, 11 magnetically coupled to a substantially ring-shaped yoke 12 at their axial ends and mutually coupled, and a coil for magnetizing these magnetic members is coaxial. And a plurality of armatures 10 which are formed so that the positions of the claw poles with respect to the field poles 21 are sequentially shifted in the circumferential direction between the phase units. The present invention relates to a claw pole motor that relatively rotates the field element 20 and the armature 10. The claw poles 13, 13 ′ have a three-dimensional shape in which the distance between the claw poles 13 and 13 ′ becomes longer toward both ends in the circumferential direction.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a claw-pole motor having a three-dimensional claw-shaped magnetic pole, and more particularly to a claw-pole motor capable of suppressing cogging torque and reducing cost.
[0002]
[Prior art]
FIG. 5 is an exploded perspective view showing a first conventional technique of a claw pole motor. In FIG. 5, reference numeral 100 denotes an armature as a stator, 200 denotes a field element as a rotor, and the armature 100 and the field element 200 constitute a three-phase inner rotor type claw pole motor. .
[0003]
The armature 100 is configured by coaxially connecting the phase units 100a, 100b, and 100c which are a natural number times the number of phases (FIG. 5 is an example of three phases, and is one time three times, that is, three). Have been. Each of the phase units 100a, 100b, and 100c includes a coil 110 formed in a ring shape, and a first soft magnetic member 120 and a second soft magnetic member 130 formed so as to surround the coil 110.
[0004]
The first soft magnetic member 120 and the second soft magnetic member 130 are high magnetic permeability members formed by processing a steel plate. In parallel with the central axis of the armature 100, a substantially flat claw pole 121 is bent downward at an equal pitch in the inner circumferential direction. On the inner peripheral portion of the yoke having the L-shaped cross section that constitutes the second soft magnetic member 130, a substantially flat claw pole 131 is also arranged at an equal pitch in the inner peripheral direction, similarly to the central axis of the armature 100. It is bent upward. That is, the adjacent claw poles 121 and 131 are magnetically coupled to separate yokes.
The claw poles 121 and 131 are alternately arranged along the inner periphery of the armature 100, and the pitch between the claw poles 121 and 131 is set to a field pole (NS pole) 210 of a field element 200 described later. Is equal to the pitch.
[0005]
On the other hand, the field element 200 has a field pole 210 and a rotation axis 220 which are arranged in a cylindrical shape, and the field pole 210 has different poles (N pole, S pole) alternately arranged in the circumferential direction. .
In a state where the field element 200 is concentrically arranged in the internal space of the armature 100, the field pole 210 and the claw poles 121 and 131 on the armature 100 side face each other.
[0006]
With this configuration, when a current flows through the coil 110 of the armature 100, the adjacent claw poles 121 and 131 are excited to have opposite polarities, so that the field pole 210 of the field element 200 is positioned at a predetermined position. Can be aspirated.
In the example of FIG. 5, the positions of the claw poles 121, 131 of the phase units 100a, 100b, 100c in the circumferential direction are sequentially shifted by 60 electrical degrees. Thus, by passing a three-phase alternating current through the three-phase unit, the field poles 210 of the field element 200 are successively attracted to the claw poles 121 and 131 of the phase units 100a, 100b and 100c, respectively. Rotate.
[0007]
This type of claw pole motor has been put to practical use as an inexpensive stepping motor, and is used, for example, for driving a drum of a printer. Further, since the illustrated motor is electrically similar to a normal three-phase permanent magnet motor, it is possible to perform a position feedback control by attaching a rotational position sensor.
Note that a typical configuration method of the first soft magnetic member 120 and the second soft magnetic member 130 is such that two yokes each having claw poles 121 and 131 sandwich the coil 110 as shown in the drawing. Are combined. When such a configuration method is adopted, each of the soft magnetic members 120 and 130 is generally formed by pressing a plate-shaped soft magnetic material.
[0008]
Next, FIG. 6 is an exploded perspective view showing a second conventional technique.
5, the magnetic flux from the field pole 210 to the surfaces of the claw poles 121 and 131 concentrates on the roots of the claw poles 121 and 131, so that the magnetic saturation becomes remarkable and the torque cannot be increased. is there.
In order to reduce the magnetic saturation and increase the torque by processing the soft magnetic material into a three-dimensional shape with a different cross-sectional area depending on the part, instead of a flat plate, and increasing the cross-sectional area of the part where the magnetic flux of the claw pole is concentrated. The structure shown in FIG. 6 has been proposed as shown in FIG.
[0009]
FIG. 6 shows an assembling process of the claw pole motor, in which the first soft magnetic member 170 and the second soft magnetic member 180 sandwich the coil 160 from both sides in the axial direction to form one phase unit 150a, and have the same configuration. The armature 150 is formed by connecting the three phase units 150a, 150b, 150c coaxially.
Reference numeral 250 denotes a field element having a field pole 260 and a rotating shaft 270.
[0010]
In the first soft magnetic member 170, 171 is a ring-shaped yoke, 172 is a projection-shaped claw pole magnetically coupled to the yoke 171 and formed so as to increase the cross-sectional area of the base portion. The claw pole 172 passes through the internal space of the coil 160 and is fitted into the concave portion 183 on the inner peripheral surface of the second soft magnetic member 180. In the second soft magnetic member 180, reference numeral 181 denotes a ring-shaped yoke, and reference numeral 182 denotes a projection-shaped claw pole magnetically coupled to the yoke 181 and formed so as to increase the cross-sectional area of the base portion. .
In this prior art, the structures of the first soft magnetic member 170 and the second soft magnetic member 180 are slightly different from each other, and are also different from the structure of the prior art of FIG. 5, but the operation principle is the same as that of FIG. is there.
[0011]
An electric motor having a three-dimensional claw pole as shown in FIG. 6 has been conventionally used as an alternator for an automobile, for example, as shown in Non-Patent Document 1 described below.
Claw poles in automotive alternators are used as field poles with fixed polarity for each pole, and eddy currents do not flow, so it is possible to form a claw pole with a mass of magnetic metal. is there.
[0012]
On the other hand, in the claw pole motor having the claw pole on the armature side as shown in FIGS. 5 and 6, since the polarity of the claw pole changes with time, it is necessary to suppress the eddy current to a practical range. Cannot use metal clumps as claw pole material.
Therefore, from the viewpoint of suppressing such eddy currents, a method of fixing and molding a magnetic powder having a surface subjected to insulation treatment is used. A motor having a claw pole formed by this type of method is disclosed in Non-Patent Document 2, for example.
[0013]
[Non-patent document 1]
"Automotive Engineering Series Engine Electrical Parts", edited by IEEJ Technical Committee, ISBN4-381-10077-8 C3053, P.E. 109
[Non-patent document 2]
A. G. FIG. Jack, et al, "Claw Pole Armature Permanent Magnet Machines Exploiting Soft Iron Powder Metallurgy," Proceedings of the IEEE International Electronics Corporation's International Electronics Corporation.
[0014]
[Problems to be solved by the invention]
In a claw pole motor having a claw pole on the armature side, the number of field poles of the field element and the number of claw poles of the armature are generally equal. A relatively large force acts in the direction in which the magnetic poles and the claw pole are aligned, and this force causes so-called cogging torque.
Further, when the distance between the claw pole and the field magnetic pole is constant in the circumferential direction of the claw pole as in the related art shown in FIGS. 5 and 6, as shown in FIG. The rate of change when the polarity of the cogging torque waveform of the unit is switched becomes large, and a large pulsation occurs in the cogging torque waveform obtained by combining all phases.
[0015]
Furthermore, the opening formed in the yoke for extracting the coil inside the soft magnetic member reduces the cross-sectional area of the magnetic path and deteriorates the magnetic characteristics, so the layout and size of this opening are optimally designed. Is required to do so.
In addition, since three-dimensional processing of a soft magnetic member generally uses an expensive mold, it is desirable to reduce the types of components from the viewpoint of cost reduction.
[0016]
Therefore, the present invention focuses on the degree of freedom of the shape when processing a soft magnetic member, improves the structure, reduces the cogging torque, improves the magnetic characteristics, and further reduces the number of types of parts to reduce costs. It is an object of the present invention to provide a claw pole motor aiming at the above.
[0017]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention described in claim 1 includes a field element in which N-pole and S-pole field poles are arranged at equal intervals and alternately in a circumferential direction,
A pair of claw poles arranged opposite to the field poles and arranged at equal pitches with these field poles are magnetically coupled to a substantially ring-shaped yoke at every other axial end, and are coupled to each other. K (K is an integer of 2 or more) are connected coaxially to each other, and the field magnetic poles are connected between these K phase units. An armature formed so that the position of the claw pole with respect to
With
A claw pole motor in which the field element and the armature are relatively rotatable by passing a current through the coil of each phase unit,
The claw pole has a three-dimensional shape such that the distance between the claw pole and the field pole becomes longer toward both ends in the circumferential direction of the claw pole.
[0018]
The invention described in claim 2 is a field element in which N-pole and S-pole field poles are alternately arranged at regular intervals in the circumferential direction;
A pair of claw poles arranged opposite to the field poles and arranged at equal pitches with these field poles are magnetically coupled to a substantially ring-shaped yoke at every other axial end, and are coupled to each other. K (K is an integer of 2 or more) are connected coaxially to each other, and the field magnetic poles are connected between these K phase units. An armature formed so that the position of the claw pole with respect to
With
A claw pole motor in which the field element and the armature are relatively rotatable by passing a current through the coil of each phase unit,
A pair of magnetic members are formed by the same member.
[0019]
According to a third aspect of the present invention, in the claw pole motor according to the second aspect, an opening for extracting a coil is formed in a peripheral portion of a yoke located on an extension of a side of the claw pole. .
[0020]
According to a fourth aspect of the present invention, in the claw pole motor according to the third aspect, the openings are arranged such that the positions of the openings coincide when the pair of magnetic members are joined.
[0021]
According to a fifth aspect of the present invention, in the claw pole motor according to any one of the first to fourth aspects, the pair of magnetic members is a soft magnetic member formed of a powder magnetic material. .
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First, FIG. 1 is a cross-sectional view of a main part showing a first embodiment of the present invention, and shows a cross-section of an axial center portion of one phase unit of a claw pole motor cut along a plane perpendicular to the axis.
In FIG. 1, reference numeral 10 denotes an armature, 11 denotes one of the soft magnetic members constituting the armature 10, and claw poles 13 protrude in the axial direction on the inner peripheral surface of a ring-shaped yoke 12 every other one. Have been. Reference numeral 13 'denotes a claw pole formed on the other soft magnetic member.
[0023]
A field element 20 is arranged concentrically in the internal space of the armature 10, and has a cylindrical field in which N poles and S poles are alternately arranged in the same number as the number of poles of the claw poles 13 and 13 '. A magnetic pole 21 and a rotating shaft 22 are provided. Note that the magnetic pole pitch of the claw poles 13 and 13 ′ is equal to the magnetic pole pitch of the field magnetic pole 21.
[0024]
Also in this embodiment, a phase unit for one phase of the armature 10 is formed by sandwiching a coil between a pair of soft magnetic members as shown in FIG. Is omitted.
Further, the armature 10 is formed by connecting K phase units coaxially (K is an integer of 2 or more, and 3 in the case of three phases). The claw poles are formed so that their positions are sequentially shifted in the circumferential direction.
[0025]
Now, conventionally, the distance between the claw pole and the field pole is constant over the circumferential direction of the claw pole, but in this embodiment, the distance between the claw poles 13 and 13 ′ and the field pole 21 is The claw poles 13, 13 ′ are longer toward the both ends in the circumferential direction. That is, in FIG. 1, a is a shortest distance line connecting the shortest distances between the claw poles 13 and 13 'and the field magnetic poles 21, and the individual claw poles 13 and 13' are opposed to the field magnetic poles 21. The surface is further away from the shortest distance line a toward the both ends in the circumferential direction of the claw poles 13 and 13 '.
[0026]
With the above structure, the change in the magnetic flux passing through the claw poles 13 and 13 'with the rotation of the field element 20 becomes gentle, and the cogging torque waveform of each phase unit as shown in FIG. Is closer to a sine wave, and the rate of change when the polarity of the cogging torque waveform is switched can be made smaller than in the prior art of FIG. Therefore, the pulsation of the combined cogging torque waveform is also reduced, and smooth rotation is possible.
If the cogging torque waveform is a complete sine wave for one phase unit, the three phases are combined and canceled out to zero. This is important in reducing the cogging torque.
[0027]
Next, FIG. 3 is an exploded perspective view of a phase unit of an armature according to a second embodiment of the present invention.
In this embodiment, a phase unit for one phase is formed by connecting two soft magnetic members 14 having the same shape and structure in opposite directions with the coil 30 interposed therebetween. In the soft magnetic member 14, reference numeral 15 denotes a ring-shaped yoke, and reference numeral 16 denotes a claw pole magnetically coupled to the yoke 15. This claw pole 16 is provided between the claw poles 16 of the same other soft magnetic member 14. Can be fitted into the recessed portion 16a formed in the recess. Reference numeral 15a denotes an opening formed in a peripheral portion of the yoke 15 for drawing out the coil 30 to the outside.
[0028]
Although the shape of the claw pole 16 in FIG. 3 is different from that of the first embodiment in FIG. 1, also in the second embodiment, as shown in FIG. The armature can be formed by making the same soft magnetic member having such a claw pole in the opposite direction and connecting two coils with the coil interposed therebetween. May be.
[0029]
Generally, since a mold for forming a three-dimensional soft magnetic member by molding a powder magnetic material is expensive, the type of mold is reduced by using two soft magnetic members 14 having the same structure as in the present embodiment. It can be reduced by half, which greatly contributes to cost reduction of the motor. In addition, it is easy to provide the concave and convex portions (the claw pole 16 and the concave portion 16a) that can be fitted to each other on the same member, so that the positioning of the pair of soft magnetic members 14 can be performed with high accuracy.
[0030]
FIG. 4 is an explanatory diagram of the armature phase unit according to the third embodiment of the present invention. In FIGS. 4A and 4B, reference numeral 17 denotes a soft magnetic member having a ring-shaped yoke 15 and a claw pole 18, and reference numeral 15a denotes an opening formed in the yoke 15 for drawing out an internal coil.
Also in this embodiment, a phase unit for one phase is formed by coupling soft magnetic members 17 having the same structure in opposite directions with a coil interposed therebetween as in FIG. Further, an armature is formed by connecting K (K is an integer of 2 or more) coaxially with the phase units, and the positions of the claw poles relative to the field poles are sequentially shifted in the circumferential direction between the phase units. The points are also the same as in each embodiment.
[0031]
Here, by forming an opening 15a in the peripheral portion of the yoke 15 located on the extension of the side 18a of the claw pole 18, the claw pole 18 of one soft magnetic member 17 is formed as shown in FIG. When the two soft magnetic members 17 are joined by fitting them into the concave portions between the claw poles of the other soft magnetic member 17, the two openings 15 a can be made to exactly coincide with each other. Coil can be easily pulled out.
In addition, since the opening 15a reduces the cross-sectional area of the magnetic path in the soft magnetic member 17, the area of the opening 15a is desirably as small as possible from the viewpoint of relaxing magnetic saturation and reducing iron loss.
[0032]
In each of the above embodiments, the case where the present invention is applied to an inner rotor type motor has been described. However, the scope of the present invention is not limited to this. For example, an outer rotor type motor or a cylindrical field element is used. Can be applied to a motor having an armature both inside and outside.
Further, the claw pole motor of the present invention can be applied to a polyphase motor other than a three-phase motor, and there is no limitation on the number of phases.
[0033]
【The invention's effect】
As described above, according to the present invention, the structure of the soft magnetic member including the claw pole and the opening for pulling out the coil is improved to reduce the cogging torque and to improve the magnetic characteristics. By using the member, the number of types of components can be reduced and the cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a sectional view of a phase unit according to a first embodiment of the present invention.
FIG. 2 is an explanatory diagram of a claw pole structure and a cogging torque waveform according to a conventional technique and an embodiment of the present invention.
FIG. 3 is an exploded perspective view of a phase unit according to a second embodiment of the present invention.
FIG. 4 is an explanatory diagram of a phase unit according to a third embodiment of the present invention.
FIG. 5 is an exploded perspective view showing a first conventional technique.
FIG. 6 is an exploded perspective view showing a second conventional technique.
[Explanation of symbols]
10: armatures 11, 14, 17: soft magnetic members 12, 15: yokes 13, 13 ', 16, 18: claw pole 15a: opening 16a: recess 18a: side 20: field element 21: field magnetic pole 22: rotating shaft 30: coil a: shortest distance line

Claims (5)

A field element in which N-pole and S-pole magnetic field poles are alternately arranged at equal intervals in the circumferential direction;
A pair of claw poles arranged opposite to the field poles and arranged at equal pitches with these field poles are magnetically coupled to a substantially ring-shaped yoke at every other axial end, and are coupled to each other. K (K is an integer of 2 or more) are connected coaxially to each other, and the field magnetic poles are connected between these K phase units. An armature formed so that the position of the claw pole with respect to
With
A claw pole motor in which the field element and the armature are relatively rotatable by passing a current through the coil of each phase unit,
A claw pole motor, wherein the claw pole has a three-dimensional shape such that the distance between the claw pole and the field pole increases toward both ends in the circumferential direction of the claw pole. A field element in which N-pole and S-pole magnetic field poles are alternately arranged at equal intervals in the circumferential direction;
A pair of claw poles arranged opposite to the field poles and arranged at equal pitches with these field poles are magnetically coupled to a substantially ring-shaped yoke at every other axial end, and are coupled to each other. K (K is an integer of 2 or more) are connected coaxially to each other, and the field magnetic poles are connected between these K phase units. An armature formed so that the position of the claw pole with respect to
With
A claw pole motor in which the field element and the armature are relatively rotatable by passing a current through the coil of each phase unit,
A claw pole motor comprising a pair of magnetic members formed of the same member. The claw pole motor according to claim 2,
A claw pole motor, wherein an opening for extracting a coil is formed in a peripheral portion of a yoke located on an extension of a side of the claw pole. The claw pole motor according to claim 3,
A claw pole motor, wherein the openings are arranged so that the positions of the openings coincide when a pair of magnetic members are joined. The claw pole motor according to any one of claims 1 to 4,
A claw pole motor, wherein the pair of magnetic members is a soft magnetic member formed of a powder magnetic material.

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