JP4500843B2 - Axial gap type motor - Google Patents

Description

  The present invention relates to an axial gap type motor.

2. Description of the Related Art Conventionally, for example, a pair of stators arranged opposite to each other so as to sandwich a rotor from both sides in the rotation axis direction is provided, and a magnetic flux loop via a pair of stators is formed with respect to a field magnetic flux generated by a permanent magnet of the rotor. A shaft gap type permanent magnet synchronous machine is known (see, for example, Patent Document 1 and Patent Document 2).
JP-A-10-271784 JP 2001-136721 A

  By the way, in the permanent magnet synchronous machine which concerns on the said prior art, suppressing generation | occurrence | production of the cogging torque and torque ripple resulting from the magnetic attraction force which acts on a rotation direction is desired.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an axial gap type motor capable of suppressing the generation of cogging torque and torque ripple.

In order to solve the above-described problems and achieve the object, an axial gap motor according to a first aspect of the present invention includes a rotor that can rotate around a rotation axis (for example, the rotor 11 in the embodiment), a rotation An axial gap including a first stator (for example, the first stator 12A in the embodiment) and a second stator (for example, the second stator 12B in the embodiment) disposed opposite to the rotor from both sides in the axial direction. The first and second stators each have an annular back yoke (for example, each yoke portion 21a, 21b in the embodiment) and a predetermined interval in the circumferential direction of the back yoke (for example, implementation) A plurality of teeth projecting toward the rotor in the direction of the rotation axis at a position for each predetermined pitch P) (for example, each of the teeth 22a and 22b in the embodiment) The circumferential pitch of the plurality of teeth of the first stator (for example, the predetermined pitch P in the embodiment) and the circumferential pitch of the plurality of teeth of the second stator (for example, the embodiment) The circumferential width of the teeth of the first stator is wider than the circumferential width of the teeth of the second stator, and is adjacent in the circumferential direction of the first stator. The slot width (for example, the slot width L1 in the embodiment) that is the interval between the teeth that match each other is the slot width (for example, the interval between the teeth that are adjacent in the circumferential direction of the second stator). slot width in the form L2) rather narrower than, the rotation axial thickness of the back yoke of the teeth of the first stator (e.g., thickness Y1) is in the embodiment, the second stay The thickness of the teeth of the back yoke in the rotational axis direction (for example, the thickness Y2 in the embodiment), the thickness of the teeth of the first stator in the rotational axis direction of the back yoke, and the second thickness. The ratio of the teeth of the stator to the thickness in the rotational axis direction of the back yoke, the ratio of the circumferential width of the teeth of the first stator, and the circumferential width of the teeth of the second stator are equal. is there.

  Furthermore, the axial gap type motor according to the second aspect of the present invention is mounted in slots between the teeth adjacent in the circumferential direction of the first stator (for example, the slots 23a and 23b in the embodiment). The number of turns of the stator winding is equal to the number of turns of the stator winding mounted in the slot between the teeth adjacent in the circumferential direction of the second stator, and the depth of the slot of the first stator in the rotational axis direction is the same. This is deeper than the depth of the slot of the second stator in the rotation axis direction.

According to the axial gap type motor according to the first aspect, the circumferential width and the slot width of the teeth are different from each other with the circumferential pitch of the teeth being equal to each other with respect to the first stator and the second stator. Thereby, it can prevent that the circumferential direction position of the circumferential direction edge part of mutual teeth corresponds, and can suppress the increase in cogging torque and torque ripple.
Further, in the first stator as compared to the second stator, as the circumferential width of the teeth is relatively wide, the thickness of the back yoke in the rotation axis direction is relatively increased, so that the back yoke of each stator is increased. The magnetic flux density between each other is equalized, a desired magnetic circuit can be optimized, for example, the magnetic flux can be prevented from passing in an unintended direction such as the radial direction, and a desired torque can be easily obtained. Can be secured.

  Furthermore, according to the axial gap type motor according to the second aspect, the first stator has a relatively narrow slot width in the first stator as compared to the second stator. As a result, the number of turns of the stator windings mounted in the slots can be made the same, and the energization states for the stator windings can be set to the same state.

Hereinafter, an axial gap type motor according to an embodiment of the present invention will be described with reference to the accompanying drawings.
The axial gap type motor 10 according to the present embodiment includes, for example, as shown in FIGS. 1 to 3, a substantially annular rotor 11 that is rotatably provided around the rotation axis O of the axial gap type motor 10, A pair of first stators 12A each having a plurality of phase stator windings that are arranged to face each other with a predetermined air gap between both sides in the direction of the axis O and generate a rotating magnetic field that rotates the rotor 11. The second stator 12B is provided.

  The axial gap type motor 10 is mounted as a drive source in a vehicle such as a hybrid vehicle or an electric vehicle, for example, and an output shaft is connected to an input shaft of a transmission (not shown), whereby the driving force of the axial gap type motor 10 is obtained. Is transmitted to drive wheels (not shown) of the vehicle via a transmission.

  Further, when the driving force is transmitted from the driving wheel side to the axial gap type motor 10 during deceleration of the vehicle, the axial gap type motor 10 functions as a generator to generate a so-called regenerative braking force, and the kinetic energy of the vehicle body is electrically converted. Recover as energy (regenerative energy). Further, for example, in a hybrid vehicle, when the rotating shaft of the axial gap type motor 10 is connected to the crankshaft of an internal combustion engine (not shown), the axial gap type motor 10 is also axially transmitted. The gap type motor 10 functions as a generator and generates power generation energy.

The first stator 12A has a substantially annular plate-shaped yoke portion 21a and a position on the opposing surface of the yoke portion 21a facing the rotor 11 at a predetermined interval (predetermined pitch P) in the circumferential direction from the position of the rotation axis O. A plurality of teeth 22a projecting toward the rotor 11 and extending in the radial direction, and a stator winding (not shown) mounted in a slot 23a between adjacent teeth 22a, 22a in the circumferential direction. Yes.
The second stator 12B has a predetermined interval (a predetermined pitch P equivalent to the first stator 12A) in the circumferential direction on the opposed surfaces of the substantially annular plate-shaped yoke portion 21b and the yoke portion 21b facing the rotor 11. A plurality of teeth 22b projecting toward the rotor 11 in the direction of the rotation axis O and extending in the radial direction from the existing position, and a stator winding (not shown) mounted in a slot 23b between adjacent teeth 22b, 22b in the circumferential direction And is configured.

Each of the stators 12A and 12B is a 6N type having, for example, six main poles (for example, U ⁺ , V ⁺ , W ⁺ , U ⁻ , V ⁻ , W ⁻ ), and one (for example, the first stator) 12A) is set so that the U ⁻ , V ⁻ , W ⁻ poles of the other (for example, the second stator 12B) face each other in the direction of the rotation axis O with respect to the U ⁺ , V ⁺ , W ⁺ poles of 12A). Yes.
For example ^U + of the first stator ^12A, V ^{+, W} + poles and ^{U -, V -, W -} 3 pieces of teeth 22a corresponding to one pole, 22a, and 22a, the second stator 12B ^U +, V ^{+, W +} poles and ^{U -, V -, W -} 3 pieces of teeth 22b corresponding to the other pole, 22b, and the 22b, is set to face in the rotation axis O direction, opposite the rotation axis O direction The energized state of the teeth 22a of the first stator 12A and the teeth 22b of the second stator 12B is set so as to be reversed in terms of electrical angle.

  For example, as shown in FIG. 3, the thicknesses of the respective yoke portions 21a and 21b of the respective stators 12A and 12B in the direction of the rotation axis O are equal from the inner side to the outer side in the radial direction. The thickness Y1 of the yoke portion 21a of 12A in the direction of the rotation axis O is thicker than the thickness Y2 of the yoke portion 21b of the second stator 12B in the direction of the rotation axis O (that is, Y1> Y2). End faces on the inner side of the rotor 11 in the direction of the rotation axis O of the yoke portions 21a and 21b of 12B, that is, the rotor facing surfaces 21Ai and 21Bi are parallel to the radial direction. Further, the end faces 21Ao and 21Bo on the outer side in the direction of the rotation axis O of the yoke portions 21a and 21b are parallel to the radial direction.

The thicknesses of the teeth 22a and 22b of the stators 12A and 12B in the direction of the rotation axis O are the same from the inner side to the outer side in the radial direction, and are equal, and the thicknesses of the teeth 22a of the first stator 12A are the same. Is thicker than the thickness T2 of the teeth 22b of the second stator 12B in the direction of the rotation axis O (that is, T1> T2), and the rotation axes O of the teeth 22a and 22b of the stators 12A and 12B. An end surface on the inner side of the rotor 11 in the direction, that is, each rotor facing surface 22A, 22B is parallel to the radial direction.
Thus, the thickness S1 (= Y1 + T1) of the first stator 12A in the direction of the rotation axis O is thicker than the thickness S2 (= Y2 + T2) of the second stator 12B in the direction of the rotation axis O.

The rotor facing surfaces 22A and 22B of the teeth 22a and 22b are substantially fan-shaped, and the circumferential widths of the rotor facing surfaces 22A and 22B gradually increase from the inner side to the outer side in the radial direction. ing.
The inner circumferential side width Ta of the rotor facing surface 22A of the first stator 12A is larger than the inner circumferential side width Tc of the rotor facing surface 22B of the second stator 12B, and the outer circumferential side width of the rotor facing surface 22A of the first stator 12A. Tb is larger than the outer peripheral side width Td of the rotor facing surface 22B of the second stator 12B.

Accordingly, the circumferential width (slot width) L1 of the slot 23a of the first stator 12A is shorter than the circumferential width (slot width) L2 of the slot 23b of the second stator 12B. That is, the circumferential positions of the circumferential ends of the teeth 22a and 22b facing each other in the direction of the rotation axis O are different.
Note that the thickness T1 of the teeth 22a of the first stator 12A in the direction of the rotation axis O (that is, the depth of the slots 23a in the direction of the rotation axis O: the slot depth) is the rotation axis O of the teeth 22b of the second stator 12B. Is larger than the thickness T2 in the direction (that is, the depth of the slot 23b in the direction of the rotation axis O: the slot depth), and the number of turns of the stator winding that can be mounted in each of the slots 23a and 23b is equal to each other. Is set to

The change ratio between the thickness Y1 of the yoke portion 21a of the first stator 12A in the direction of the rotation axis O and the thickness Y2 of the yoke portion 21b of the second stator 12B in the direction of the rotation axis O, and the first stator 12A. The change ratio between the circumferential width of the teeth 22a (for example, the outer circumferential side width Tb) and the circumferential width of the teeth 22b of the second stator 12B (for example, the outer circumferential side width Td) is, for example, equal (Y1: Y2 = Tb: Td).
That is, in the teeth 22a of the first stator 12A as compared with the teeth 22b of the second stator 12B, the thickness in the rotation axis direction of the yoke portion 21a of the first stator 12A is increased as the circumferential width becomes relatively large. By being relatively thicker than the yoke portion 21b of the second stator 12B, the magnetic flux density between the yoke portions 21a and 21b of the respective stators 12A and 12B is equalized. For example, the magnetic flux in an unintended direction such as the radial direction. Is prevented from passing.

  For example, for each of the stators 12A and 12B, the ratio of the slot width L1 to the slot width L2 is (L1: L2 = 6: 8), and the ratio of the slot depth (that is, the thickness T1 of the teeth 22a and the teeth 22b The ratio of the thickness T2 is (T1: T2 = 20: 15), and the thickness Y1 of the yoke portion 21a in the direction of the rotation axis O and the thickness of the yoke portion 21b of the second stator 12B in the direction of the rotation axis O. The ratio with Y2 is (Y1: Y2 = 12: 10.5).

  As shown in FIG. 2, for example, the rotor 11 includes a plurality of main magnet pole portions 31,..., A plurality of sub magnet portions 32,..., 32, and a rotor frame 33 made of a nonmagnetic material. The main magnet pole portion 31 and the sub magnet portion 32 are accommodated in the rotor frame 33 in a state of being alternately arranged in the circumferential direction.

For example, as shown in FIG. 2, the rotor frame 33 includes an inner peripheral tubular portion 35 and an outer peripheral tubular portion connected by a plurality of radial ribs 34,... The part 36 and an annular plate projecting inward from the inner peripheral surface of the inner peripheral cylindrical part 35 are connected to an external drive shaft (for example, an input shaft of a vehicle transmission). The connection part 37 is provided.
In this embodiment, since the inner peripheral cylindrical portion 35 of the rotor frame 33 is connected to an external drive shaft, the radially inner side of the radial rib 34 is the shaft portion side, and the radial rib 34 The radially outer side is the rim portion side.
The cross-sectional shapes of the radial ribs 34 in the radial direction are the same from the outer side to the inner side in the radial direction.

For example, the main magnet pole portion 31 sandwiches the main permanent magnet piece 41 from both sides in the thickness direction and a substantially fan-shaped main permanent magnet piece 41 magnetized in the thickness direction (that is, the rotation axis O direction). The main permanent magnet pieces 41 and 41 of the main magnet pole portions 31 and 31 that are configured to include a pair of magnetic members 42 and 42 and are adjacent to each other in the circumferential direction are set so that the magnetization directions thereof are different from each other. ing.
The pair of magnetic members 42, 42 has a substantially sector shape in which the cross-sectional shape in the thickness direction is the same as that of the main permanent magnet piece 41.

The plurality of main magnet pole portions 31,..., 31 accommodated in the rotor frame 33 are sandwiched by the inner peripheral cylindrical portion 35 and the outer peripheral cylindrical portion 36 from both sides in the radial direction, and also in the radial direction. The ribs 34 are arranged adjacent to each other in the circumferential direction.
In the rotor frame 33, the main permanent magnet piece 41 of each main magnet pole portion 31 is sandwiched from both sides in the circumferential direction by two radial ribs 34, and the thickness of the main permanent magnet piece 41 in the rotation axis O direction is: Similar to the radial ribs 34, they are equivalent from the radially outward to the inward.
Further, the thickness of the magnetic member 42 in the direction of the rotation axis O is the same from the inner side to the outer side in the radial direction.

The sub-magnet portion 32 includes a pair of sub-permanent magnet pieces 43 and 43 that sandwich the radial ribs 34 from both sides in the direction of the rotation axis O in the rotor frame 33, and a pair of opposed permanent magnet portions 43 facing each other in the direction of the rotation axis O. The sub permanent magnet pieces 43 and 43 are magnetized in a direction (substantially circumferential direction) perpendicular to the rotation axis O direction and the radial direction, respectively, and the magnetization directions are different from each other.
The thickness of the secondary permanent magnet piece 43 in the direction of the rotation axis O is the same from the inside in the radial direction to the outside, and the circumferential width of the secondary permanent magnet piece 43 is the inside in the radial direction. From the outside, it is equivalent.
In the rotor frame 33, the sub permanent magnet pieces 43 and 43 of the sub magnet portions 32 and 32 adjacent in the circumferential direction sandwich the magnetic member 42 of the main magnet pole portion 31 from both sides in the circumferential direction. In addition, the sub permanent magnet piece 43 and the magnetic member 42 are made into the substantially rectangular shape where the cross-sectional shape with respect to the circumferential direction is mutually equivalent.

  In FIG. 2, which shows the rotor frame 33 of the rotor 11 and the components other than the rotor frame 33 (that is, the main magnet pole portion 31 and the sub magnet portion 32) separated from each other, a pair facing each other in the direction of the rotation axis O. A space portion 34a in which the radial rib 34 of the rotor frame 33 is disposed is formed between the sub permanent magnet pieces 43, 43 and between the main permanent magnet pieces 41, 41 adjacent in the circumferential direction.

The pair of sub permanent magnet pieces 43, 43 facing each other in the circumferential direction via the magnetic member 42 have different magnetization directions.
The pair of sub permanent magnet pieces 43 and 43 arranged on one side in the direction of the rotation axis O have the same polarity as the magnetic pole on one side of the main permanent magnet piece 41 magnetized in the direction of the rotation axis O. A pair of sub-permanent magnet pieces 43, 43 that are opposed to each other and arranged on the other side in the direction of the rotation axis O are magnetic poles having the same polarity as the magnetic pole on the other side of the main permanent magnet piece 41 magnetized in the direction of the rotation axis O. Are arranged to face each other.

That is, for example, with respect to the main permanent magnet piece 41 in which one side in the rotation axis O direction is an N pole and the other side is an S pole, a pair of magnetic members 42 are sandwiched from both sides in the circumferential direction on one side in the rotation axis O direction. The sub permanent magnet pieces 43, 43 are arranged so that their N poles face each other in the circumferential direction, and a pair of sub permanent magnet pieces 43 sandwiching the magnetic member 42 from both sides in the circumferential direction on the other side in the rotation axis O direction. , 43 are arranged so that their S poles face each other in the circumferential direction.
Accordingly, the magnetic fluxes of the main permanent magnet piece 41 and the sub permanent magnet pieces 43 and 43 are converged by the magnetic lens effect due to the so-called permanent magnet Halbach arrangement, and the effective magnetic flux linked to the stators 12 and 12 is relatively relative to each other. It is going to increase.

In this embodiment, the radial ribs 34 of the rotor frame 33 and the thicknesses of the main permanent magnet pieces 41 of the main magnet pole portions 31 in the direction of the rotation axis O are the same from the outer side to the inner side in the radial direction. As a result, the width of the inner peripheral cylindrical portion 35 of the rotor frame 33 in the rotation axis O direction is equal to the width of the outer peripheral cylindrical portion 36 in the rotation axis O direction.
In other words, the radial cross-sectional area of the rotor 11 is a predetermined constant value between the inner circumferential side cylindrical portion 35 and the outer circumferential side cylindrical portion 36 of the rotor frame 33, and is directed from the radially outer side toward the inner side. It is said to be unchanged.

As described above, according to the axial gap type motor 10 according to the present embodiment, the circumferential pitch P of the teeth 22a and 22b is equal to the first stator 12A and the second stator 12B. By setting the circumferential width and slot width of the teeth 22a and 22b to be different from each other, the circumferential positions of the circumferential ends of the teeth 22a and 22b facing each other in the direction of the rotation axis O are different, and cogging is performed. Torque and torque ripple can be suppressed.
Further, in the first stator 12A compared to the second stator 12B, the slot depth in the direction of the rotation axis O is relatively deepened with the relatively narrow slot width, so that the slots 23a, 23a, The number of turns of the stator windings attached to 23b can be made the same, and the energization state of the stator windings can be set to the same state.
In addition, the teeth 22a of the first stator 12A have a relatively wider circumferential width than the teeth 22b of the second stator 12B, and therefore the first stator 12A has a structure that is larger than that of the yoke portion 21b of the second stator 12B. In the yoke portion 21a, the thickness in the direction of the rotation axis O is relatively increased, so that the magnetic flux density of the magnet magnetic flux between the yoke portions 21a and 21b of the stators 12A and 12B is equalized, and a desired magnetic circuit is formed. For example, the magnetic flux can be prevented from passing in an unintended direction such as the radial direction, and a desired torque can be easily ensured.

  In the embodiment described above, the secondary magnet portion 32 may be omitted, or one of the pair of secondary permanent magnet pieces 43, 43 constituting the secondary magnet portion 32 may be omitted.

1 is an exploded perspective view of an axial gap motor according to an embodiment of the present invention. It is a disassembled perspective view of the rotor of the axial gap type motor which concerns on one Embodiment of this invention. It is the top view which looked at the axial gap type motor concerning one embodiment of the present invention from the diameter direction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Axial gap type motor 11 Rotor 12A 1st stator 12B 2nd stator 21a, 21b Yoke part (back yoke)
22a, 22b Teeth 23a, 23b Slot 31 Main magnet pole portion 32 Sub magnet portion 33 Rotor frame 34 Radial rib 35 Inner peripheral side cylindrical portion 36 Outer peripheral side cylindrical portion 41 Main permanent magnet piece 43 Sub permanent permanent magnet piece

Claims (2)

An axial gap type motor comprising: a rotor rotatable around a rotation axis; and a first stator and a second stator arranged to face the rotor from both sides in the rotation axis direction,
The first and second stators include an annular back yoke and a plurality of teeth protruding toward the rotor in the rotational axis direction at positions at predetermined intervals in the circumferential direction of the back yoke,
The circumferential pitch of the plurality of teeth of the first stator is equal to the circumferential pitch of the plurality of teeth of the second stator,
The circumferential width of the teeth of the first stator is wider than the circumferential width of the teeth of the second stator,
Slot width is the spacing between the teeth adjacent in the circumferential direction of the first stator, rather narrower than the slot width is the spacing between the teeth adjacent in the circumferential direction of the second stator,
The thickness of the teeth of the first stator in the rotational axis direction of the back yoke is thicker than the thickness of the teeth of the second stator in the rotational axis direction of the back yoke,
The ratio of the thickness in the rotation axis direction of the back yoke of the teeth of the first stator to the thickness in the rotation axis direction of the back yoke of the teeth of the second stator, and the circumferential width of the teeth of the first stator And the ratio of the second stator to the circumferential width of the teeth are equal to each other. The number of turns of the stator windings installed in the slots between the teeth adjacent in the circumferential direction of the first stator and the stator windings installed in the slots between the teeth adjacent in the circumferential direction of the second stator Is equal to the number of turns
2. The axial gap motor according to claim 1, wherein a depth of the slot of the first stator in a rotation axis direction is deeper than a depth of the slot of the second stator in a rotation axis direction.

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