JP5439904B2 - Rotating electric machine - Google Patents

Description

  The present invention relates to a rotating electrical machine.

  2. Description of the Related Art Conventionally, in a rotating electrical machine having an inner rotor having a permanent magnet and an outer stator having an electromagnet, a rotating electrical machine in which a part of the outer stator is cut is known.

International Publication WO2004-015842 Pamphlet

  However, in this type of rotating electrical machine, there is a risk that the magnetic flux generated by the permanent magnet located radially inward of the rotating shaft with respect to the notch portion leaks to the outside of the rotating electrical machine, increasing the rotational resistance of the inner rotor. It was.

  Therefore, an object of the present invention is to provide a rotating electrical machine that can reduce the leakage of magnetic flux generated by a permanent magnet of an inner rotor from a notch portion of an outer stator.

  In the present invention, the bypass member that allows the magnetic flux to pass from the N-pole portion to the S-pole portion at the radially inner side of the rotation shaft with respect to the notch portion is arranged in the axial direction of the rotation shaft with respect to the inner rotor. The most important feature is that they are arranged facing each other with a gap.

  According to the present invention, the magnetic flux generated by the permanent magnet at a position radially inward of the rotating shaft with respect to the notch portion can be directed from the N pole portion to the S pole portion via the bypass member. Can be prevented from leaking to the outside, and the rotational resistance of the inner rotor caused by the leakage of magnetic flux can be reduced.

FIG. 1 is a side view of the rotating electrical machine according to the first embodiment of the present invention. 2 is a cross-sectional view taken along the line II-II in FIG. FIG. 3 is a perspective view showing a part of the internal configuration of the rotating electrical machine according to the first embodiment of the present invention. FIG. 4 is an enlarged perspective view showing a part of FIG. 3, and is an explanatory view schematically showing magnetic flux. FIG. 5 is a view of a part of the inner rotor of the rotating electrical machine according to the first embodiment of the present invention as seen from the axial direction. FIG. 6 is a view of a part of the inner rotor of the rotating electrical machine according to the first embodiment of the present invention as viewed from the axial direction, and schematically shows a cross-sectional area of a portion where magnetic flux is emitted from the N pole portion toward the bypass member. It is explanatory drawing shown in. FIG. 7 is a view of a part of the inner rotor of the rotating electrical machine according to the first modification of the first embodiment of the present invention as seen from the axial direction. FIG. 8 is a view of a part of the inner rotor of the rotating electrical machine according to the second modification of the first embodiment of the present invention when viewed from the axial direction. FIG. 9 is a cross-sectional view showing a part of the internal configuration of the rotating electrical machine according to the third modification of the first embodiment of the present invention. FIG. 10 is a perspective view showing a part of the internal configuration of the rotating electrical machine according to the fourth modification of the first embodiment of the present invention. FIG. 11 is a perspective view showing a part of the internal configuration of the rotating electrical machine according to the second embodiment of the present invention. FIG. 12 is a side view showing a part of the internal configuration of the rotating electrical machine according to the second embodiment of the present invention.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the drawings. In addition, the same component is contained in the following several embodiment and modification. Therefore, in the following, common reference numerals are given to those similar components, and redundant description is omitted.

  (First Embodiment) In this embodiment, a case where the rotating electrical machine 1 is implemented as an in-wheel motor provided in a wheel Wh of an automobile is illustrated. As shown in FIG. 1, components such as the brake caliper Bc are arranged in the wheel Wh, and there are cases where the installation space of the rotating electrical machine 1 is restricted. In this respect, the rotating electrical machine 1 according to the present embodiment is provided with a notch portion 7 by notching a part of the entire circumference of the case 2 and the outer stator 3, and the notch portion 7 includes components such as the brake caliper Bc. By accommodating at least a part, the high-power rotating electrical machine 1 having a larger diameter can be arranged while avoiding interference with the component.

  The rotating electrical machine 1 includes an outer stator 3 fixed in the case 2 and an inner rotor 4 that is rotatably supported by the case 2.

  As shown in FIG. 3, the outer stator 3 has a plurality of electromagnets 5 arranged at a constant pitch along the circumferential direction of the rotation axis Ax. In the present embodiment, the rotating electrical machine 1 is configured as a three-phase (U-phase, V-phase, W-phase) synchronous rotating electrical machine, and the U-phase, V-phase, and W-phase electromagnets 5 are in a predetermined order (for example, (U phase, V phase, W phase).

  Further, the outer stator 3 is formed with a notched portion 7 where a portion of the entire circumference is notched and the electromagnet 5 is not disposed. In the case of a three-phase synchronous rotating electric machine, the circumferential length of the cutout portion 7 is preferably set to be a multiple of 3 of the electromagnet 5. In the present embodiment, the length of the cutout portion 7 is a length corresponding to 6 (= 3 × 2) electromagnets 5.

  The electromagnet 5 is a coil formed by an arcuate base portion 5a that forms the outer peripheral portion of the outer stator 3, a tooth portion 5b that protrudes radially inward from the base portion 5a, and a lead wire wound around the tooth portion 5b. Part 5c.

  The inner rotor 4 has a plurality of permanent magnets 6 (6n, 6s) arranged at a constant pitch along the circumferential direction of the rotation axis Ax. In the present embodiment, the inner rotor 4 is configured as an embedded (IPM type) inner rotor 4 in which a rectangular plate-like permanent magnet 6 is embedded in an accommodation hole 4b formed along the axial direction formed in the main body 4a. Has been. Moreover, the main-body part (core) 4a can be comprised as a laminated steel plate which laminated | stacked multiple annular steel plates of the same shape, for example.

  As shown in FIGS. 3 and 4, the permanent magnet 6 is arranged along the outer periphery of the inner rotor 4 so as to form a V shape that opens toward the outer periphery of the inner rotor 4, and the N pole is radially outward. The V-shaped portions formed by the permanent magnets 6n facing the surface and the V-shaped portions formed by the permanent magnets 6s whose south pole faces the radially outer side are alternately arranged along the circumferential direction. These V-shaped portions have the same shape. With this configuration, as shown in FIGS. 4 and 5, the inner rotor 4 has an N pole portion 10 n formed by two permanent magnets 6 n with the N pole facing radially outward (upper side in FIG. 5), and the S pole. S pole portions 10s formed by two permanent magnets 6s facing radially outward are alternately arranged at a constant pitch along the circumferential direction. The N pole portion 10n and the S pole portion 10s (the outer circumferential surface on the radially outer side of the inner rotor 4) are separated from the electromagnet 5 (the inner circumferential surface on the radially inner side of the outer stator 3) with respect to the gap gr (see FIG. 2) and are arranged to face each other. In the present embodiment, the circumferential pitch of the N-pole portion 10n and the S-pole portion 10s and the circumferential pitch of the electromagnet 5 are determined by the inner rotor 4 with respect to the three electromagnets 5 adjacent to each other in the outer stator 3. The N pole portion 10n and the S pole portion 10s adjacent to each other are set so as to face each other.

  Here, in the present embodiment, as shown in FIG. 3 and the like, the bypass members 8 are arranged with gaps ga on both sides in the axial direction of the inner rotor 4 on the radially inner side of the cutout portion 7. It is. The bypass member 8 is made of a magnetic material. Therefore, in the portion of the inner rotor 4 that is radially inward of the notch portion 7, as shown in FIG. 4, the magnetic flux Fb passing through the bypass member 8 from the N pole portion 10n toward the S pole portion 10s, that is, the N pole portion. The magnetic flux Fb that exits in the axial direction from 10n and enters the bypass member 8, passes through the bypass member 8 along the circumferential direction, exits the bypass member 8 in the axial direction, and enters the S pole portion 10s is formed. With this configuration, it is possible to suppress the magnetic flux generated by the permanent magnet 6 from leaking to the outside of the rotating electrical machine 1 at the radially inner portion of the notched portion 7 of the inner rotor 4, and the inner rotor 4 generated by the leakage of the magnetic flux. Rotational resistance can be reduced.

  The bypass member 8 is attached to a fixed portion such as the case 2 and the outer stator 3 of the rotating electrical machine 1, and is provided only at a portion facing the radially inner side of the notch portion 7. Further, it has a constant thickness in the axial direction and a constant width in the radial direction, and has an arc shape substantially along the axial end surface 4c of the inner rotor 4 (that is, substantially along the circumferential direction of the rotation axis Ax). It is comprised as a strip-shaped member bent in the direction.

  In such a configuration, as shown in FIG. 4, a magnetic flux Fb that reaches the S pole portion 10 s from the N pole portion 10 n via the bypass member 8 is formed in a portion that is radially inward with respect to the cutout portion 7. . In the present embodiment, since the S pole portions 10s are arranged on both sides in the circumferential direction of the N pole portion 10n, the magnetic flux Fb is formed so as to be divided into two on both sides in the circumferential direction from the N pole portion 10n.

  In such a configuration, the magnetic flux Fb also moves in the circumferential direction in the bypass member 8 as the inner rotor 4 rotates. Therefore, the bypass member 8 is made of a soft magnetic material (eg, iron, silicon steel, permalloy, sendust, permendur, soft ferrite, amorphous magnetic alloy, nanocrystal magnetic alloy, etc.) having a small coercive force and a high magnetic permeability. Is preferred. This is because the use of a soft magnetic material can reduce the hysteresis loss associated with the change of the magnetic flux Fb in the bypass member 8.

  Further, as shown in FIG. 3, it is preferable that the bypass member 8 is provided corresponding to only a portion that is radially inward of the cutout portion 7 of the inner rotor 4. When the bypass member 8 is extended beyond the cutout portion 7 to a portion that is radially inward of the electromagnet 5, the magnetic flux density of the magnetic flux Fr formed between the electromagnet 5 and the permanent magnet 6 is increased in the bypass member 8. This is because the amount of leakage decreases and the efficiency (drive efficiency or power generation efficiency) decreases.

  The radial width W (see FIG. 3) of the bypass member 8 is equal to or smaller than the width W1 (see FIG. 5) of the axial end surface 4c of the inner rotor 4, and the diameters of the N pole portion 10n and the S pole portion 10s. It is preferable that the width be equal to or greater than the width W2 in the direction (see FIG. 5). This is because when the width W is set to a value exceeding the width W1, the radial size and weight of the rotating electrical machine 1 are increased, and when the width W is set to be less than the width W2, the magnetic resistance of the magnetic flux Fb is increased. It is.

  Further, regarding the axial thickness of the bypass member 8, as shown in FIG. 2, the distance t2 from the end surface 4c on the one axial side of the inner rotor 4 to the end surface 8a on the one axial side of the bypass member 8 is set to It is preferable to set the distance t1 or less from the end surface 4c on the one axial side to the end 5d on the one axial side of the coil portion 5c. By doing so, it is possible to suppress the bypass member 8 from protruding beyond the coil portion 5c in the axial direction and increasing the size and weight of the rotating electrical machine 1 in the axial direction.

  Further, the cross-sectional area Sb (see FIG. 4) perpendicular to the circumferential direction of the bypass member 8 is set to the area Sn of the axial end surface 4c of the N pole portion 10n of the inner rotor 4 (the mutual relationship between the two permanent magnets 6n forming the N pole portion 10n). The area of the substantially fan-shaped region surrounded by the edge facing each other, the peripheral edge of the inner rotor 4 and the concentric arc connecting the radially inner ends of the permanent magnet 6n (see FIG. 6), and the S pole portion 10s of the inner rotor 4 It is preferable to set substantially the same as the area of the axial end face 4c (same as Sn in FIG. 6). With this configuration, it is possible to secure a sufficient cross-sectional area of the bypass member 8 that allows the magnetic flux Fb to pass therethrough, and thus it is possible to suppress the size of the bypass member 8 from becoming unnecessarily large.

  Further, the inner rotor 4 is preferably configured as an embedded (IPM type) inner rotor 4 in which a permanent magnet 6 is embedded in the main body 4a. In the case of the surface type (SPM type) in which the permanent magnet is exposed on the outer peripheral surface of the inner rotor, the portion where the magnetic flux is generated is only on the outer peripheral surface side of the inner rotor. The magnetic flux passes through the gap between the inner rotor and the outer stator (the gap gr in FIG. 2), the magnetic path is largely detoured and it is difficult to secure a sufficient cross-sectional area, and the magnetic resistance is increased. In this regard, in this embodiment, the bypass member 8 is opposed to both the N pole portion 10n and the S pole portion 10s with an air gap ga in the axial direction so that a linear and short magnetic path is formed. Since it can be formed, the magnetic resistance of the magnetic flux Fb can be lowered.

  In the present embodiment, the bypass members 8 are arranged on both sides in the axial direction with respect to the inner rotor 4. If the bypass member is disposed only on one side in the axial direction of the inner rotor, magnetic flux tends to wrap around the bypass member from the other side of the inner rotor, so that the magnetic resistance increases. In this regard, in the present embodiment, since the bypass members 8 are arranged on both sides in the axial direction, the magnetic resistance can be lowered accordingly. However, if the bypass member 8 is disposed only on one side of the inner rotor 4 in the axial direction, there is an advantage that an increase in the size of the rotating electrical machine 1 and an increase in weight can be suppressed.

  Moreover, you may form the main-body part 4a of the inner rotor 4 with magnetic isotropic materials, such as a dust core and a metal glass molding. When the main body portion 4a is made of a magnetic isotropic material, the reduction in efficiency can be suppressed as much as the generation of in-plane eddy currents can be suppressed compared to the case where the main body portion 4a is formed as a laminated steel plate.

  As described above, according to the present embodiment, the magnetic flux Fb generated by the permanent magnet 6 can be directed from the N pole part 10 n to the S pole part 10 s via the bypass member 8 at a position facing the notch part 7. Therefore, it is possible to suppress the magnetic flux Fb from leaking to the outside and increasing the rotational resistance of the inner rotor 4.

  (First Modification of First Embodiment) Even when the permanent magnet 6 is disposed along the radial direction of the rotation axis Ax as in the first modification shown in FIG. 7, the N pole portion 10n is bypassed. Since the magnetic flux Fb reaching the S pole portion 10s can be formed via the member 8, the effect of the first embodiment can be obtained. Also in this case, the cross-sectional area Sb (see FIG. 4) orthogonal to the circumferential direction of the bypass member 8 is set to the area Sn (the two permanent magnets 6n forming the N pole portion 10n) of the axial end surface 4c of the N pole portion 10n of the inner rotor 4. Area of a substantially fan-shaped region surrounded by the mutually opposing edges, the peripheral edge of the inner rotor 4 and the concentric arc connecting the radially inner ends of the permanent magnets 6n (see FIG. 7), and the S pole of the inner rotor 4 It is preferable to set substantially equal to the area of the axial end face 4c of the portion 10s (same as Sn in FIG. 7). With this configuration, it is possible to secure a sufficient cross-sectional area of the bypass member 8 that allows the magnetic flux Fb to pass therethrough, and thus it is possible to suppress the size of the bypass member 8 from becoming unnecessarily large.

  (Second Modification of First Embodiment) In the inner rotor 4B according to the second modification shown in FIG. 8, the main body 4a is a columnar body 4Bb made of a magnetic isotropic material such as a dust core or a metal glass molding. And a holding portion 4Ba that holds the columnar body 4Bb so as to surround the columnar body 4Bb. Specifically, the holding portion 4Ba is made of a laminated steel plate, and the N pole portion 10n and the S pole portion 10s (not shown) of the holding portion 4Ba are provided with peripheral portions of the N pole portion 10n and the S pole portion 10s. A through-hole 4d penetrating in the axial direction is formed in a substantially triangular cross section so as to occupy most of the portion excluding the column, and the columnar body 4Bb is accommodated and fixed in the through-hole 4d. According to such a configuration, it is possible to suppress an in-plane eddy current due to the magnetic flux Fb in the N-pole portion 10n and the S-pole portion 10s, thereby suppressing a reduction in efficiency. Even when it is difficult to increase the strength and rigidity of a portion made of a magnetic isotropic material (columnar body 4Bb in this modification), the structure of the portion is configured by the holding portion 4Ba having higher strength and rigidity than that portion. Can be maintained. In this modification, the columnar body 4Bb corresponds to the first member, and the holding portion 4Ba corresponds to the second member.

  (Third Modification of First Embodiment) In the rotating electrical machine 1C according to the third modification shown in FIG. 9, the bypass member 8 is provided on the notch portion 7 side from the end face 4e on the radially outer side (arrow Ro) of the inner rotor 4 ( In FIG. 9, it is projected upward. Since the magnetic force (attraction force) acting between the electromagnet 5 (outer stator 3) and the inner rotor 4 is weakened in the portion where the notched portion 7 is provided, the inner rotor 4 is provided with the notched portion 7 with respect to the rotation axis Ax. The magnetic force F acting on the opposite side (lower side in FIG. 9) increases. There is a possibility that the magnetic force F becomes a radial excitation force on the inner rotor 4 to generate noise and vibration, and wear of a portion supporting the inner rotor 4 may be promoted. In this regard, in this modification, the magnetic force Fc is applied to the inner rotor 4 from the bypass member 8 by projecting the bypass member 8 toward the notch portion 7, and the magnetic force F is reduced by the magnetic force Fc. Can be suppressed.

  (Fourth Modification of First Embodiment) In a rotating electrical machine 1D according to a fourth modification shown in FIG. 10, a plurality of cutout portions 7 are arranged on opposite sides with the rotation axis Ax interposed therebetween. The radial magnetic force F (see FIG. 9) acting on the inner rotor 4 shown in the third modification is increased by arranging the notched portion 7 and the electromagnet 5 with the rotation axis Ax interposed therebetween. When the plurality of cutout portions 7 are arranged with the rotation axis Ax interposed therebetween as in this modification, it is easy to balance the radial magnetic force acting on the inner rotor 4, so the radial excitation force on the inner rotor 4 It becomes possible to prevent the noise from increasing and contributing to noise and vibration or promoting the wear of the portion supporting the inner rotor 4.

  (Second Embodiment) As shown in FIGS. 11 and 12, in a rotating electrical machine 1E according to this embodiment, an electromagnet unit 12 is provided in place of the bypass member 8. FIG. That is, the same operation as that in which the electromagnet unit 12 is disposed with the gap ga provided on the axially outer side of the inner rotor 4 that is radially inward of the notched portion 7 and the electromagnet 5 is disposed in the notched portion 7. Is going to get. The electromagnet unit 12 includes a plurality of electromagnets 11 arranged at the same pitch as the electromagnet 5 arranged on the outer stator 3. In the present embodiment, the rotating electrical machine 1E is configured as a three-phase (U-phase, V-phase, W-phase) synchronous rotating electrical machine, and the cutout portion 7 has a length corresponding to three electromagnets 5. Therefore, the electromagnet unit 12 is provided with three electromagnets 11 and becomes a U phase, a V phase, and a W phase, respectively.

  The electromagnet unit 12 includes a base portion 11a, a tooth portion 11b that protrudes from the base portion 11a in the axial direction toward the inner rotor 4, and a coil portion 11c formed by a lead wire wound around the tooth portion 11b. Have. The base portion 11a is attached to a fixed portion such as the case of the rotating electrical machine 1E, the outer stator 3, and the like, and is provided only at a portion facing the radially inner side of the notch portion 7. And it has a constant thickness in the axial direction and a constant width in the radial direction, and has an arc shape substantially along the axial end surface 4c of the inner rotor 4 (that is, substantially along the circumferential direction of the rotation axis Ax). It is comprised as a strip-shaped member bent in the direction. A gap ga is formed between the electromagnet 11 and the end face 4 c of the inner rotor 4.

  According to the present embodiment described above, similar to the first embodiment, the merit obtained by providing the notch portion 7 can be obtained, and the electromagnet unit 12 corresponding to the notch portion 7 is provided, so that it corresponds to the notch portion 7. The magnetic flux generated by the permanent magnet 6 can be effectively used by the electromagnet unit 12 to suppress a decrease in performance as the rotating electrical machine 1E due to the provision of the cutout portion 7.

  Also in the present embodiment, the inner rotor 4 is preferably an embedded type (IPM type) in which the permanent magnet 6 is embedded in the main body 4a. This is because the magnetic resistance in the magnetic path between the inner rotor 4 and the electromagnet unit 12 can be reduced as compared with the case of the surface type (SPM type) as in the case of the first embodiment.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments, and various modifications can be made. For example, even when the rotating electrical machine of the present invention is configured as a generator, the above-described functions and effects can be obtained. Moreover, specifications, such as a rotary electric machine and a bypass member, are not limited to the said embodiment.

1, 1C, 1D, 1E Rotating electrical machine 3 Outer stator 4, 4B Inner rotor 4Ba Holding part (second member)
4Bb Columnar body (first member)
4a Body portion 4c End surface (in the axial direction of the inner rotor) 4e End surface (outer in the radial direction of the inner rotor) 5 Electromagnet 5a Base portion 5b Teeth portion 5c Coil portion 5d End portion (of the coil portion) 6, 6n, 6s Permanent magnet 7 Notch portion 8 Bypass member 8a (Bypass member) end face 10n N pole part 10s S pole part 11 Electromagnet Ax Rotating shaft Fb Magnetic flux Sb Cross sectional area Sn area ga, gr gap t1, t2 distance

Claims (11)

An outer stator having a plurality of electromagnets arranged along the circumferential direction of the rotating shaft, and an inner rotor having a plurality of permanent magnets arranged along the circumferential direction, wherein the inner rotor is formed by the permanent magnets. The N pole part and the S pole part are arranged along the circumferential direction on the outer side in the radial direction of the rotating shaft, and are arranged to face the plurality of electromagnets with a gap on the inner side in the radial direction. In the rotating electrical machine in which the outer stator is formed with a notched portion where a portion of the entire circumference is notched and an electromagnet is not disposed
A bypass member that allows a magnetic flux to pass from the N-pole portion to the S-pole portion of the inner rotor in the radially inner portion with respect to the notch portion is opened in the axial direction with respect to the inner rotor. A rotating electric machine characterized by being arranged to face each other.   The rotating electrical machine according to claim 1, wherein the bypass member is formed of a soft magnetic material.   The rotating electrical machine according to claim 1, wherein the bypass member is provided only in a portion facing the notch portion.   The rotating electrical machine according to claim 1, wherein the bypass member is disposed on at least one side in an axial direction with respect to the inner rotor. The electromagnet has an arc-shaped base portion of the outer stator, a tooth portion protruding radially inward from the base portion, and a coil portion wound around the tooth portion,
The coil portion projects from the end surface on one side in the axial direction of the inner rotor to the one side in the axial direction,
The distance from the end surface on one side in the axial direction of the inner rotor to the end surface on one side in the axial direction of the bypass member is determined from the end surface on one side in the axial direction of the inner rotor to the end on the one side in the axial direction of the coil portion. The rotating electrical machine according to any one of claims 1 to 4, wherein the rotating electrical machine is set to a distance or less.   The cross-sectional area perpendicular to the circumferential direction of the bypass member is set to be approximately equal to the area of the axial end face of the N pole portion of the inner rotor and the area of the axial end face of the S pole portion of the inner rotor. The rotating electrical machine according to any one of claims 1 to 5.   The rotating electrical machine according to claim 1, wherein the permanent magnet is embedded in a main body portion of the inner rotor.   The rotating electrical machine according to claim 7, wherein at least a part of the main body is made of a magnetic isotropic material.   The rotation according to claim 8, wherein the main body includes a first member formed of the magnetic isotropic material and a second member that holds the first member so as to surround the first member. Electric.   The rotating electrical machine according to any one of claims 1 to 9, wherein the bypass member protrudes from the end surface on the radially outer side of the inner rotor to the cutout portion side. An outer stator having a plurality of electromagnets arranged along the circumferential direction of the rotating shaft, and an inner rotor having a plurality of permanent magnets arranged along the circumferential direction, wherein the inner rotor is formed by the permanent magnets. The N pole part and the S pole part are arranged along the circumferential direction on the outer side in the radial direction of the rotating shaft, and are arranged to face the plurality of electromagnets with a gap on the inner side in the radial direction. In the rotating electrical machine in which the outer stator is formed with a notched portion where a portion of the entire circumference is notched and an electromagnet is not disposed
An electric rotating machine characterized in that an electromagnet is disposed with an air gap on the outer side in the axial direction of the radially inner portion of the inner rotor with respect to the notched portion.

Images