JP5630397B2 - Rotating electric machine stator core - Google Patents

Description

  The present invention relates to a stator core using a powder magnetic core, and relates to a stator core for a rotating electrical machine capable of reducing eddy current loss generated in a powder magnetic core.

  Conventionally, a stator core of a rotating electrical machine has been produced by compressing a silicon steel plate in which thin steel plates are laminated, or a green compact manufacturing material containing soft magnetic powder together with a lubricating component and a resin binder into a predetermined shape in a mold. Formed by a magnetic core. However, in a dust core with respect to a silicon steel plate, the eddy current loss generated in the dust core is large, and it is difficult to use a stator core with a dust core particularly in a high-speed rotation region.

  Therefore, in the powder magnetic core described in Patent Document 1, as shown in the partially cut perspective view of the stator core in FIG. 18, when the powder magnetic core 100 as the stator core is formed by pressure molding, it is indicated by a bidirectional arrow H1. The iron powder density of the intermediate part 100a, which is an intermediate part in the direction in which the magnetomotive force is generated, is formed to be smaller than that of the surface 100b. By this molding, the specific resistance of the intermediate portion 100a becomes higher than that of the surface 100b, and the resistance value of the path through which the eddy current flows (eddy current path) increases. As a result, eddy current loss is reduced.

  Further, when the dust core 100 is laminated with the insulating layer 101 sandwiched therebetween, the insulating layer 101 can reduce the magnetomotive force H1 with respect to the resistance of the eddy current path, thereby reducing eddy current loss.

JP 2010-263042 A

  By the way, in the above-described powder magnetic core of Patent Document 1, by forming the iron powder density of the intermediate portion 100a to be smaller than that of the surface 100b, the specific resistance of the intermediate portion 100a is made higher than that of the surface 100b and the vortex. Current loss is reduced. However, if the specific resistance of the intermediate portion 100a is increased so as to reduce this eddy current loss, the iron powder density is often lowered and the magnetization characteristics are deteriorated. In this case, the rotational torque in the rotating electric machine of the electric motor or generator is increased. The problem of deteriorating arises.

  This invention is made | formed in view of such a situation, and can reduce the eddy current loss resulting from an eddy current, without producing the fault that the density of iron powder falls and a rotational torque falls. It aims at providing the stator core of a rotary electric machine.

In order to achieve the above-mentioned object, the invention according to claim 1 is formed by a compacted magnetic core, and is disposed around a rotor that is fixed to a rotating shaft and rotates with a gap therebetween. In a stator core of a rotating electrical machine comprising a plurality of slots arranged at intervals, teeth between the slots, and a core back on the outer peripheral side of the teeth, at least one of a groove portion or a convex portion in the circumferential direction is provided on the outer peripheral surface of the core back. It is characterized by providing.

  According to this configuration, the eddy current i1 that flows clockwise or counterclockwise around the magnetic flux φ1 generated in the circumferential direction in the core back flows along the uneven shape. For this reason, the path (eddy current path) through which the eddy current i1 passes becomes longer, the resistance value of the eddy current path becomes higher, and the eddy current i1 becomes difficult to flow, so the eddy current loss is reduced. Further, according to the above configuration, in the present invention, the eddy current i1 does not occur without the disadvantage that the density of the iron powder is reduced and the rotational torque is reduced as in the prior art in which the specific resistance of the powder magnetic core is increased. The eddy current loss caused by can be reduced.

  The invention according to claim 2 is characterized in that a plurality of the groove portions or convex portions are formed on the outer peripheral surface of the core back at a predetermined interval in the rotation axis direction.

  According to this configuration, since a plurality of uneven shapes are formed on the outer peripheral surface of the core back, the eddy current i1 flows across the plurality of uneven shapes in an orthogonal state. For this reason, the eddy current path becomes longer, the resistance value of the eddy current path becomes higher, and the eddy current i1 becomes more difficult to flow, so that the eddy current loss is further reduced.

The invention described in claim 3 is characterized in that a cooling pipe through which the refrigerant passes is disposed in the groove portion.

  According to this configuration, since the stator core can be cooled by the refrigerant passing through the cooling pipe, heat generation of the stator core can be suppressed.

It is sectional drawing of the rotating shaft direction which shows the structure of the rotary electric machine to which the stator core by the powder magnetic core which concerns on this embodiment was applied. (A) The top view which looked at the stator core shown in FIG. 1 from the rotating shaft direction, (b) It is X1-Y1 sectional drawing shown to (a). (A) It is a figure which shows the flow direction of magnetic flux (phi) 1 and eddy current i1 which generate | occur | produce in the stator core of this embodiment, (b) It is a figure which shows the resistance value of the uneven | corrugated shape vicinity of a stator core. (A) The figure which shows the flow direction of magnetic flux (phi) 1 and eddy current i1a which generate | occur | produce in the stator core of a general shape, (b) The figure which shows the resistance value of the uneven | corrugated shape vicinity of a stator core. (A) Partial cross-sectional perspective view showing the thickness dimension of the general-shaped stator core in the rotational axis direction, (b) Partial cross-sectional perspective view showing the dimensions of the concave and convex portions of the outer peripheral surface of the stator core of the present embodiment in the rotational axis direction. FIG. It is a figure which shows the eddy current loss ratio which flows through the stator core of a general shape, and the stator core of this invention when a 200-Hz electric current is supplied to a stator coil. (A) The figure which shows the locus | trajectory in which a recessed part is intermittently formed along a ring shape in a stator core, (b) The figure which shows the locus | trajectory in which a recessed part is formed in a semicircle. It is a figure which shows the structure of the cooling mechanism which fitted the cooling pipe to the recessed part of the stator core of this embodiment. (A) is the top view which looked at the stator core by the powder magnetic core which concerns on a 1st reference example from the rotating shaft direction, (b) It is X2-Y2 sectional drawing shown to (a). (A) The figure which shows the flow direction of magnetic flux (phi) 1 and eddy current i1 which generate | occur | produce in the stator core of a 1st reference example , (b) It is a figure which shows the resistance value of the uneven | corrugated shape vicinity of a stator core. (A) The figure which shows the flow direction of magnetic flux (phi) 1 and eddy current i1a which generate | occur | produce in the stator core of a general shape, (b) The figure which shows the resistance value of the uneven | corrugated shape vicinity of a stator core. (A) The top view which looked at the stator core by the powder magnetic core which concerns on a 2nd reference example from the rotating shaft direction, (b) X3-Y3 sectional drawing shown to (a), (c) The direction shown by arrow Y1 to (a) It is the figure of the teeth internal peripheral surface seen from. (A) It is a figure which shows the flow direction of magnetic flux (phi) 2 and eddy current i2 which generate | occur | produce in the teeth of the stator core of a 2nd reference example , (b) It is a figure which shows the resistance value of the uneven | corrugated shape vicinity of a stator core. (A) The figure which shows the flow direction of magnetic flux (phi) 2 and eddy current i2a which generate | occur | produce in the stator core of a general shape, (b) It is a figure which shows the resistance value of the uneven | corrugated shape vicinity of a stator core. (A) is the top view which looked at the stator core by the powder magnetic core which concerns on a 3rd reference example from the rotating shaft direction, (b) is an enlarged view of one teeth part enclosed with the broken-line frame shown to (a), (c). These are figures of the teeth internal peripheral surface seen from the direction shown by arrow Y1 in (a). (A) It is a figure which shows the flow direction of magnetic flux (phi) 2 and eddy current i2 which generate | occur | produce in the teeth of the stator core of a 2nd reference example , (b) It is a figure which shows the resistance value of the uneven | corrugated shape vicinity of a stator core. (A) The figure which shows the flow direction of magnetic flux (phi) 2 and eddy current i2a which generate | occur | produce in the stator core of a general shape, (b) It is a figure which shows the resistance value of the uneven | corrugated shape vicinity of a stator core. It is a partial cross section perspective view which shows an intermediate part and an insulating layer when a prior art is applied to the stator core of a general shape.

Embodiments and reference examples of the present invention will be described below with reference to the drawings. However, parts corresponding to each other in all the drawings in this specification are denoted by the same reference numerals, and description of the overlapping parts will be omitted as appropriate.
( Embodiment)
FIG. 1 is a cross-sectional view in the direction of a rotating shaft showing a configuration of a rotating electrical machine to which a stator core by a magnetic powder core according to the present embodiment is applied, and FIG. 2A is a plan view of the stator core shown in FIG. FIG. 2B is an X1-Y1 cross-sectional view shown in FIG. That is, FIG. 2B is a cross-sectional view in the direction of the rotation axis of the stator core similar to FIG.

  A rotating electrical machine 10 shown in FIG. 1 is used by being mounted on a vehicle such as a hybrid vehicle or an electric vehicle, for example. The rotating electrical machine 10 includes a stator core 17 formed of a compressed magnetic core and a stator coil 16, and a rotor core formed of a silicon steel plate. 12 and end plate 14, and includes a front housing 10a, a rear housing 10b, etc., which accommodate the stator 18 and the rotor 15, and are connected and fixed by fastening bolts (not shown). Has been.

  The stator 18 has an annular shape as shown in FIG. 2A, and has a plurality of slots 17a arranged in the circumferential direction, teeth 17b between the slots 17a, and a core back 17c on the outer peripheral side of the slots 17a. The stator core 17 and a three-phase coil 16 wound around a slot 17a of the stator core 17 and connected to an inverter (not shown) for power conversion. The coil 16 is a copper wire, for example. The stator 18 is fixed by being sandwiched between the front housing 10a and the rear housing 10b, and is disposed on the outer peripheral side of the rotor 15 via a predetermined gap in the radial direction.

  The rotor 15 rotates integrally with the rotary shaft 11 rotatably supported by the front housing 10a and the rear housing 10b via the bearing 10c, and is fitted and fixed to the outer peripheral surface of the rotary shaft 11. The rotor 15 includes a rotor core 12 disposed to face the inner peripheral side of the stator 18 via a predetermined gap in the radial direction, and a plurality of rotor cores 12 disposed at predetermined intervals in the circumferential direction inside the rotor core 12. The permanent magnet 13 has a pair of annular end plates 14 and 14 that are fitted and fixed to the outer peripheral surface of the rotating shaft 11 and are in contact with both end surfaces of the rotor core 12 in the rotating shaft direction. The pair of end plates 14 and 14 are formed of a nonmagnetic material such as aluminum or SUS, for example.

  A feature of the present embodiment is that a groove (concave portion) 21 is provided on the outer peripheral surface of the core back 17c of the stator core 17, and the concave portion 21 and the convex portion 22 are formed. Specifically, a concave groove (or a concave portion) 21 is formed in an annular shape along the outer peripheral direction on the outer peripheral surface of the core back 17c having a rectangular cross section shown in FIG. The convex portion 22 is formed by forming a plurality (two in this example) at predetermined intervals in the direction H1. However, on the outer peripheral surface of the core back 17c, convex ridges 22 as the convex portions 22 are formed in an annular shape along the outer peripheral direction, and a plurality (three in this example) of the convex ridges 22 are formed in the magnetomotive force direction H1. The recess 21 may be formed by forming. The concave portion 21 and the convex portion 22 are also referred to as concave and convex shapes 21 and 22. Moreover, the number of the recessed part 21 or the convex part 22 may be one.

  In the case of such concavo-convex shapes 21 and 22, as shown in FIG. 3A, the magnetic flux φ1 flows in the circumferential direction from the front to the back of the drawing in the stator core 17, and the magnetic flux amount of the magnetic flux φ1 decreases. Assuming that the eddy current i1 circulates around the periphery of the rectangular cross section of the stator core 17 in the clockwise direction around φ1 so as to prevent the change of the magnetic flux φ1, the concave portion 21 and the convex portion 22 are in the middle of the circulation. Flowing along.

  Here, when the magnetic flux φ1 is generated in the stator core 100 having the shape shown in FIG. 4A in the same direction as in FIG. 3A and the amount of magnetic flux is reduced, the direction around the magnetic flux φ1 is clockwise. Eddy current i1a flows. The resistance value of the path (eddy current path) on the outer peripheral surface through which this eddy current i1a flows is, for example, a value indicated by R1, R2, R3, R4, and R5 in FIG.

  On the other hand, in the stator core 17 of the present embodiment, since the outer peripheral surfaces thereof are concave and convex shapes 21 and 22, the resistance value of the eddy current path on the outer peripheral surface through which the eddy current i1 flows is shown in FIG. As indicated by R1, R1a, R2, R2a, R3, R3a, R4, R4a, and R5, it is increased by R1a, R2a, R3a, and R4a as compared with the stator core 100 of FIG.

  That is, according to the stator core 17 of the present embodiment, since the outer peripheral surfaces are 21 and 22, the path through which the eddy current i1 flows becomes longer than that of the stator core 100 having a flat outer peripheral surface in FIG. The resistance value of the path becomes high. Thus, when the resistance value of the eddy current path becomes high, the eddy current i1 becomes difficult to flow, so the eddy current loss is reduced. This effect of reducing the eddy current loss is more effective because the current concentrates on the surface due to the skin effect when the rotating electrical machine 10 rotates at high speed.

  Here, the eddy current loss generated in the stator core having a thickness dimension L1 of 20 mm in the rotation axis direction shown in FIG. 5A and the dimension in the rotation axis direction of the recess 21 on the outer peripheral surface of the stator core 17 shown in FIG. FIG. 6 shows a simulation result comparing eddy current loss generated in the stator core formed with the concave and convex shapes 21 and 22 in which L2 is 6 mm and the convex portion 22 has a dimension L3 in the rotation axis direction of 4 mm. In addition, it simulated by making the material characteristic of the stator core of Fig.5 (a) and FIG.5 (b) the same.

  When a current of 200 Hz is passed through the stator coil 16, as shown in FIG. 6, the eddy current loss ratio of the entire stator core is as shown in FIG. 5 (1) when the eddy current loss of the stator core 100 in FIG. The eddy current loss of the stator core 17 of b) decreases between 0.8 and 0.9.

  By the way, in the stator core in which the specific resistance of the intermediate portion of the powder magnetic core is increased to reduce the eddy current loss, the density of the iron powder is lowered, the magnetization characteristics are deteriorated, and the rotational torque in the rotating electrical machine is reduced. However, in the stator core 17 of the present embodiment, by forming the concave and convex shapes 21 and 22 on the outer peripheral surface of the stator core 17, the eddy current path is lengthened to increase its resistance value, thereby reducing the eddy current loss. Unlike the stator core in which the specific resistance of the intermediate portion of the powder magnetic core is increased, the magnetization characteristics do not deteriorate, and the rotating torque of the rotating electrical machine 10 does not decrease. Therefore, the eddy current loss caused by the eddy current i1 can be reduced without causing the disadvantage that the density of the iron powder decreases and the rotational torque decreases.

  Further, the concave and convex shapes 21 and 22 on the outer peripheral surface of the stator core 17 are not continuous annular as described above, but intermittently along the outer peripheral surface of the stator core 17 as indicated by a line segment C1 in FIG. It may be formed in a semicircular shape as indicated by a line segment C2 in FIG. The semicircular shape may be an arc shape close to a semicircle. Also in these cases, since a part of the outer peripheral surface of the stator core 17 has the uneven shapes 21 and 22, eddy current loss can be reduced.

  Further, as shown in FIG. 8, a cooling pipe 30 is fitted into the recess 21 of the stator core 17, and a cooling mechanism that circulates the refrigerant stored in the refrigerant storage part 31 by a pump 32 in the fitted cooling pipe 30. 33 may be provided. The pump 32 is driven by the rotating electrical machine 10, the discharge port 32 a is connected to the inlet 30 a of the cooling pipe 30 by a pipe 34 a, and the suction port 32 b is connected to the outlet 30 b of the cooling pipe 30 by a pipe 34 b.

With such a cooling mechanism 33, if the refrigerant is circulated through the cooling pipe 30 by the pump 32, the stator core 17 can be cooled, and thereby heat generation of the stator core 17 can be suppressed.
(First Reference Example )
FIG. 9A is a plan view of a stator core formed of a powder magnetic core according to the first reference example as viewed from the direction of the rotation axis, and FIG. 9B is a cross-sectional view taken along the line X2-Y2 shown in FIG.

The stator core 17-1 of the first reference example shown in FIG. 9 is characterized in that grooves (recesses) 31 are provided on the annular end surfaces on both sides (or one side) viewed from the rotational axis direction of the core back 17c, and the recesses are formed in an annular shape. 31 and the convex part 32 are formed. Specifically, at least one (two in this example) grooves (or recesses) concentrically around the rotation shaft 11 are formed on the annular end surface of the core back 17c having a rectangular cross section shown in FIG. 9B. ) 31 is formed. Furthermore, two or more groove portions are formed, thereby forming a convex portion. Note that at least one or more protrusions (convex portions) 32 may be formed concentrically around the rotation shaft 11 on the annular end surface of the core back 17c. Furthermore, two or more protrusions (convex parts) 32 may be formed, and thereby the concave part 32 may be formed. Here, the concave portion 31 and the convex portion 32 are also referred to as the concave and convex shapes 31 and 32.

  In the case of such concavo-convex shapes 31 and 32, as shown in FIG. 10A, the magnetic flux φ1 flows through the stator core 17-1 in the circumferential direction from the front side to the back side of the drawing, and the magnetic flux amount of the magnetic flux φ1 is Assuming that the eddy current i1 is decreasing, the eddy current i1 circulates around the rectangular section of the stator core 17 in the clockwise direction around φ1 so as to prevent the change of the magnetic flux φ1. It flows along the part 32.

  Here, when the magnetic flux φ1 is generated in the stator core 100 as shown in FIG. 11A in the same direction as in FIG. 10A and the amount of magnetic flux decreases, the direction around the magnetic flux φ1 is clockwise. Eddy current i1a flows through For example, the resistance value of the path of the annular end surface of the core back 17c through which the eddy current i1a flows is a value indicated by R11, R12, R13, R14, and R15 in FIG.

On the other hand, in the stator core 17-1 of the present reference example, the end surface in the rotation axis direction has the irregular shapes 31 and 32, and therefore the resistance value of the path of the end surface in the rotation axis direction of the core back 17c through which the eddy current i1 flows. As shown by R11, R11a, R12, R12a, R13, R13a, R14, R14a, and R15 in FIG. 10B, it increases by R11a, R12a, R13a, and R14a than the stator core 100 having a general shape.

That is, according to the stator core 17-1 of the present reference example, the end surfaces in the rotation axis direction are concave and convex shapes 31 and 32, so that the axial end surfaces as shown in FIG. The path through which the eddy current i1 flows becomes longer and the resistance value of the eddy current path becomes higher. Therefore, since the resistance value of the eddy current path becomes high and the eddy current i1 hardly flows, the eddy current loss is reduced.

In the stator core 17-1 Thus by compressed powder magnetic core of the first reference example, as in the present embodiment, the rotational torque down the density of iron powder as higher the stator core resistivity of the intermediate portion of the compressed powder magnetic core The eddy current loss caused by the eddy current i1 can be reduced without causing the disadvantage of lowering.

Further, the concave and convex shapes 31 and 32 of the annular axial end face of the stator core 17-1 are not continuous annular shapes as described in the present embodiment, and are indicated by a line segment C1 in FIG. Thus, it may be formed intermittently on the inner periphery of the annular end surface of the stator core 17-1, and as indicated by the line C2 in FIG. Even if it is formed in an arc shape on the inner periphery of the annular end face, eddy current loss can be reduced.

Further, as in the present embodiment, a cooling mechanism 33 fitted with the cooling pipe 30 may be provided in the concave portion 31 of the stator core 17-1, and in this case, the heat generation of the stator core 17-1 may be provided. Can be suppressed.

Furthermore, the uneven shapes 21 and 22 of the present embodiment may be added to the outer peripheral surface of the stator core 17-1. In this case, the uneven shapes 21 and 22 are formed on the outer peripheral surface of the stator core 17-1 and the axial end surface of the core back 17c. 22 and the concavo-convex shapes 31 and 32 are provided, so that the eddy current loss can be further reduced.
( Second reference example )
12A is a plan view of a stator core formed of a magnetic powder core according to a second reference example as viewed from the direction of the rotation axis, FIG. 12B is a cross-sectional view taken along the line X3-Y3 shown in FIG. 12A, and FIG. ) Is a view of the inner peripheral surface of the tooth viewed from the direction indicated by the arrow Y1 in FIG.

The feature of the stator core 17-2 of the second reference example shown in FIG. 12 is that a concave portion 41 and a convex portion 42 are formed on the surface of the teeth 17b-1 of the stator core 17-2 on the slot 17a side. Specifically, as shown in FIGS. 12B and 12C, a groove (or recess) 41 extending in the radial direction is formed on the surface of the teeth 17b-1 on the slot 17a side, and the groove is further formed. The convex portion 42 is formed by forming a plurality of 41 (two in this example) at predetermined intervals in the rotation axis direction. However, protrusions 42 are formed as protrusions 42 extending in the radial direction on the surface of the teeth 17b-1 on the slot 17a side, and a plurality of protrusions 42 (2 in this example) are formed at predetermined intervals in the rotation axis direction. The recess 41 may be formed by forming. In addition, the recessed part 41 and the convex part 42 are also called uneven | corrugated shape 41,42. Moreover, the number of the recessed part 41 or the convex part 42 may be one.

  When such uneven shapes 41 and 42 are provided, as shown in FIG. 13A, the magnetic flux φ2 enters the inner peripheral surface of the teeth 17b-1 and flows in the radial direction, and the magnetic flux amount of the magnetic flux φ2 is Assuming a decrease (when flowing from the front to the back of the drawing), the eddy current i2 flows in the clockwise direction around φ2 so as to prevent the change of the magnetic flux φ2. This flow becomes a path that goes around the inner circumference of the cross section in the axial direction of the teeth 17b-1 orthogonal to the direction in which the magnetic flux φ2 is generated, and the eddy current flows along the concave portion 41 and the convex portion 42 provided in the middle of the round. It will be.

  Here, when the magnetic flux φ2 and the magnetic flux amount are reduced in the teeth 117b of the stator core 100 shown in FIG. 14A in the same direction as FIG. 13A, the eddy current is clockwise around the magnetic flux φ2. i2a flows. That is, the eddy current i2a flows in a direction that goes around the inner circumference of the cross section in the axial direction of the tooth 117b. Of the resistance of the eddy current path through which the eddy current i2a flows, the resistance value of the right path of the symmetrical inner peripheral surface of the teeth 117b is, for example, R21, R22, R23, R24, as shown in FIG. R25.

On the other hand, in the tooth 17b-1 of the present reference example , since the axial cross section has the concave and convex shapes 41 and 42, the resistance value of the right path is R21, as shown in FIG. R21a, R22, R22a, R23, R23a, R24, R24a, R25, and the resistance is increased by R21a, R22a, R23a, R24a compared to the stator core 100 of FIG.

In other words, according to the stator core 17-2 of the present reference example , the surface on the slot 17a side of the teeth 17b-1 has the concave and convex shapes 41 and 42. Therefore, the eddy current i2 flows more than the stator core 100 having the flat surface of the teeth 117b. The path becomes longer and the resistance value of the eddy current path becomes higher. This makes it difficult for the eddy current i2 caused by the magnetic flux φ2 to flow, so that the eddy current loss is reduced. As described above, in the stator core 17-2 using the powder magnetic core of the second reference example , the eddy current loss caused by the eddy current i2 is reduced without causing the disadvantage that the density of the iron powder decreases and the rotational torque decreases. Can do.
( Third reference example )
FIG. 15A is a plan view of a stator core formed of a powder magnetic core according to the third reference example as seen from the direction of the rotation axis, and FIG. 15B is a view of one tooth portion surrounded by a broken line frame shown in FIG. FIG. 15C is an enlarged view and FIG. 15C is a view of the inner peripheral surface of the tooth viewed from the direction indicated by the arrow Y1 in FIG.

The feature of the stator core 17-3 of the third reference example shown in FIG. 15 is that grooves (recesses) 51 are provided on the end surfaces (tooth end surfaces) on both sides (or one side) viewed from the rotation axis direction of the teeth 17b-2. 51 and the convex part 52 are formed. Specifically, as shown in FIGS. 15B and 15C, a groove (or recess) 51 extending along the radial direction is formed on the end surface of the teeth 17 b-2, and the groove 51 is at least one. One or more (one in this example) is that the convex portions 52 are formed by forming them at predetermined intervals in the circumferential direction. However, it is also possible to form protrusions as protrusions 52 extending along the radial direction on the end face of the tooth 17b-2 and to provide at least one protrusion 52 in the circumferential direction. Further, the concave portion 51 may be formed by forming two or more convex portions at a predetermined interval. In addition, the recessed part 51 and the convex part 52 are also called uneven | corrugated shape 51,52.

  In the case of such uneven shapes 51 and 52, as shown in FIG. 16A, the magnetic flux φ2 enters the inner peripheral surface of the teeth 17b-2 and flows in the radial direction (when flowing from the front to the back of the drawing). ), Assuming that the magnetic flux amount of the magnetic flux φ2 is decreasing, the eddy current i2 flows clockwise around φ2 so as to prevent the change of the magnetic flux φ2. This flow becomes a path that goes around the inner circumference of the cross section in the axial direction of the tooth 17b-1 orthogonal to the direction in which the magnetic flux φ2 is generated, and the eddy current flows along the concave portion 51 and the convex portion 52 in the middle of the round.

  Here, when the magnetic flux φ2 is generated in the teeth 117b of the stator core 100 shown in FIG. 17A in the same direction as in FIG. 16A and the amount of the magnetic flux is reduced, the direction around the magnetic flux φ2 is clockwise. An eddy current i2a flows through. That is, the eddy current i2a flows in a direction that goes around the inner circumference of the cross section in the axial direction of the tooth 117b. Of the resistance of the eddy current path through which the eddy current i2a flows, the resistance value of the path at the upper end of the axially symmetric axial cross section of the teeth 117b is, for example, R31 and R32 as shown in FIG. , R33.

On the other hand, in the teeth 17b-2 of the present reference example , the shape of both end surfaces in the axial direction is the concave and convex shapes 51 and 52 in the vertically symmetric axial cross section. For example, the resistance value of the upper path is As shown in FIG. 16B, R31, R31a, R32, R32a, and R33 are obtained, and the resistance increases by R31a and R32a as compared with the stator core 100 shown in FIG.

That is, according to the stator core 17-3 of the present reference example , the end surfaces of the teeth 17b-2 are uneven shapes 51 and 52. Therefore, the path through which the eddy current i2 flows is longer than the stator core 100 having the same surface of the teeth 117b. As a result, the resistance value of the eddy current path increases. This makes it difficult for the eddy current i2 caused by the magnetic flux φ2 to flow, so that the eddy current loss is reduced. As described above, in the stator core 17-3 using the powder magnetic core of the third reference example , the eddy current loss caused by the eddy current i2 is reduced without causing the disadvantage that the density of the iron powder decreases and the rotational torque decreases. Can do.

Furthermore, the uneven shape 41, 42 of the second reference example may be added to the surface of the tooth 17b-2 on the slot 17a side. In this case, the uneven shape 41, 42 is provided on the surface and end surface of the tooth 17b-2 on the slot 17a side. Since both 42 and the concavo-convex shapes 51 and 52 are provided, the eddy current loss can be further reduced.

  Note that the corners of the above-described uneven shapes 21, 22, 31, 32, 41, 42, 51, 52 may be chamfered or may be R-shaped convex curved surfaces.

DESCRIPTION OF SYMBOLS 10 Rotating electric machine 11 Rotating shaft 12 Rotor core 13 Permanent magnet 14 End plate 15 Rotor 16 Coil 17, 17-1, 17-2, 17-3 Stator core 17a Slot 17b, 17b-1, 17b-2 Teeth 17c Core back 18 Stator 21 , 31, 41, 51 Recess (concave groove)
22, 32, 42, 52 Convex part 30 Cooling pipe 31 Refrigerant storage part 32 Pump 33 Cooling mechanism 34a, 34b Piping φ1, φ2 Magnetic flux i1, i1a, i2, i2a Eddy current

Claims (3)

A plurality of slots, which are formed by a powder magnetic core, are arranged around a rotor that is fixed to a rotating shaft and rotates with a gap therebetween, and are arranged at predetermined intervals in the circumferential direction, and teeth of the teeth. In the stator core of a rotating electrical machine consisting of a core back on the outer peripheral side,
A stator core for a rotating electrical machine, comprising at least one of a groove portion or a convex portion in a circumferential direction on an outer peripheral surface of the core back.   2. The stator core of a rotating electrical machine according to claim 1, wherein a plurality of the groove portions or the convex portions are formed at predetermined intervals in the rotation axis direction on the outer peripheral surface of the core back. The stator core of a rotary electric machine according to claim 1 or 2 in the groove, characterized in that the cooling pipes which refrigerant passes are provided.

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