JP2008131802A - Fan motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fan motor in which the laminated core and the winding can be cooled sufficiently. <P>SOLUTION: In the fan motor 10, a plurality of protrusion groups 44 (heat dissipating portions) provided on the laminated core 24 are arranged in a cooling wind passage 54 formed between the laminated core 24 and a center piece 50. Since the protrusion group 44 is arranged to be shifted in the circumferential direction from the protrusion group 44 of a core plate group 42 adjoining in the axial direction, a clearance 56 is formed between the axial directions of the protrusion group 44. When a cooling wind flow is formed in the cooling wind passage 54 in the axial direction as a fan 18 rotates, the cooling wind flows into the clearance 56 formed between the axial directions of the protrusion group 44, and the protrusion group 44 of each core plate group 42 as well as the inner circumferential surface of the ring portion 30 is exposed to the cooling wind. Consequently, the area of the laminated core 24 exposed to the cooling wind is enlarged so that the laminated core 24 and the winding 26 attached to the laminated core 24 can be cooled sufficiently. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fan motor, and more particularly to a fan motor having a structure for cooling a laminated core on which windings are mounted.

Conventionally, the following are known as this type of fan motor (for example, see Patent Document 1). For example, the fan motor described in Patent Document 1 is provided with a cylindrical center piece, and an annular laminated core is fixed to the outer peripheral surface of the center piece. A plurality of concave portions formed along the axial direction are provided on the inner peripheral surface of the laminated core in the circumferential direction, and a plurality of vent holes communicating in the axial direction between the laminated core and the center piece are provided by the concave portions. Is formed. And a cooling wind is introduce | transduced into a vent hole with rotation of a fan, and a laminated core is cooled in connection with this.
Japanese Patent Laid-Open No. 11-332203

  However, in the fan motor described in Patent Document 1, a cooling air flow in the axial direction is formed along the vent hole formed between the laminated core and the center piece, but only by the amount corresponding to the surface area of the vent hole. The laminated core was exposed to cooling air. Accordingly, there is room for improvement in order to increase the area of the laminated core exposed to the cooling air and to sufficiently cool the laminated core and the winding.

  The present invention has been made in view of the above problems, and an object of the present invention is to expand the area of the laminated core exposed to the cooling air, and to sufficiently cool the laminated core and the winding. Is to provide.

  In order to solve the above-mentioned problem, the fan motor according to claim 1, an armature having a laminated core on which windings are mounted, a center piece that supports the armature, and a rotation supported by the center piece In a fan motor configured to include a shaft, a rotor supported by the rotating shaft and rotatably provided on a radially outer side of the armature, and a fan coupled to the rotor so as to be integrally rotatable. The laminated core has a plurality of radially extending teeth portions extending radially outward on the outer peripheral surface of the annularly configured ring portion, and a convex portion extending radially inward on the inner peripheral surface of the ring portion. A plurality of core plates that are radially provided, and a plurality of core plates stacked in the axial direction so that the convex portions of the core plates are aligned with each other in the circumferential direction. And a plurality of the core plate groups are stacked in the axial direction so that the convex portions of the core plate groups are displaced from each other in the circumferential direction, and the center piece is formed of the laminated core. A cooling air passage is formed along an axial direction between the ring portion and an inner peripheral surface of the ring portion formed by an axially extending through hole formed by each ring portion, and the fan is cooled with rotation. An axial cooling air flow is formed in the air passage.

  In the fan motor according to claim 1, the laminated core is configured to include a plurality of core plates, and each core plate is radially inward of the inner peripheral surface of the annularly configured ring portion. A plurality of convex portions extending in a radial direction are provided. The laminated core forms a set of core plate groups by overlapping a plurality of core plates in the axial direction so that the convex portions of the core plates are aligned with each other in the circumferential direction. A plurality of core plate groups are overlapped in the axial direction so that the part groups are displaced in the circumferential direction.

  Further, the laminated core configured as described above has a through hole extending in the axial direction by the ring portion of each core plate, and a center piece is inserted into the through hole. And between the inner peripheral surface of the ring part which forms this through-hole, and the outer peripheral surface of a center piece, the cooling air path is formed along the axial direction.

  Here, a plurality of convex portions extending inward in the radial direction from the inner peripheral surface of the ring portion are arranged in the cooling air passage. In addition, since the convex groups are arranged so as to be offset in the circumferential direction from the convex groups of the core plate groups adjacent in the axial direction, a gap is formed between the axial directions of the convex groups. Therefore, when an axial cooling air flow is formed in the cooling air passage along with the rotation of the fan, this cooling air flows into the gap formed between the axial directions of the convex group, and only the inner peripheral surface of the ring portion. Instead, the convex group of each core plate group is exposed to the cooling air.

  As described above, according to the fan motor of the first aspect, it is possible to expand the area of the laminated core exposed to the cooling air and sufficiently cool the laminated core and the windings attached to the laminated core. It becomes.

  The fan motor according to claim 2 is the fan motor according to claim 1, wherein when the number of the tooth portions of each core plate is N, each core plate group is an adjacent core plate in the axial direction. It is overlapped with the group at a position shifted by 360 ° / N in the circumferential direction.

  According to the fan motor of claim 2, when the number of teeth portions of each core plate is N, each core plate group has an angle of 360 ° / N in the circumferential direction with the core plate group adjacent in the axial direction. They are overlaid at different positions. Accordingly, by overlapping each core plate group in the axial direction in a regular arrangement, a gap can be reliably formed between the axial directions of the convex portions provided on the core plate group. Thereby, the cooling effect of the lamination | stacking core and the coil | winding with which this lamination | stacking core was mounted | worn can be improved reliably.

  The fan motor according to claim 3 is the fan motor according to claim 1 or 2, wherein the convex portion of each core plate is the center of the slot portion between the axial center of the core plate and the teeth portion. It is characterized by including at least the site | part arrange | positioned on the virtual line which connects.

  In this case, the center of the slot portion corresponds to a portion located at the center between the tooth portions in the circumferential direction of the ring portion.

  According to the fan motor of the third aspect, the convex portion of each core plate is configured to include at least a portion disposed on an imaginary line connecting the axial center of the core plate and the center of the slot portion. Accordingly, in each core plate, the tooth portions and the convex portions are alternately arranged along the circumferential direction on both sides of the ring portion. Thereby, for example, even when the ring portion is configured to be narrow in the radial direction, the convex portion is disposed between the adjacent tooth portions, thereby widening the magnetic flux flow path through which the magnetic flux between the adjacent tooth portions flows. Can be configured. As a result, it is possible to ensure an efficient flow of magnetic flux.

  The fan motor according to claim 4 is the fan motor according to any one of claims 1 to 3, wherein the fan is provided with a fan boss part integrally connected to the rotor, The fan boss part is provided with an auxiliary fan for assisting the formation of the cooling air flow with the rotation of the fan.

  According to the fan motor of the fourth aspect, the axial cooling air flow is formed in the cooling air passage along with the rotation of the fan. At this time, the cooling is performed by the auxiliary fan provided in the fan boss portion of the fan. The formation of the wind flow is assisted, and the amount of cooling air flowing through the cooling air passage is increased. Thereby, the cooling effect of the laminated core and the windings attached to the laminated core can be further enhanced.

  In order to solve the above problem, a fan motor according to claim 5 is supported by an armature having a laminated core on which windings are mounted, a center piece for supporting the armature, and the center piece. A rotating shaft, a rotor supported by the rotating shaft and rotatably provided on the outer side in the radial direction of the armature, and a fan connected to the rotor so as to be integrally rotatable. In the motor, the laminated core has a through hole formed in the radial central portion thereof along the axial direction, and the center piece is inserted into the through hole and the shaft is interposed between the outer peripheral surface of the center piece. Provided with a ring portion that forms a cooling air passage along the direction, and extends toward the center piece on the inner peripheral surface of the ring portion with a gap between each other in the axial direction. Is configured to have a plurality of heat radiation portions, the fan is characterized in that it is configured to form a cooling air flow in the axial direction in the cooling air passage with rotation.

  In the fan motor according to the fifth aspect, a through hole is formed through the laminated core in the radial direction at the central portion in the radial direction, and a center piece is inserted into the through hole. And between the inner peripheral surface of the ring part which forms this through-hole, and the outer peripheral surface of a center piece, the cooling air path is formed along the axial direction. A plurality of heat radiating portions extending toward the center piece are arranged on the inner peripheral surface of the ring portion, and the heat radiating portions are arranged with a gap between each other in the axial direction. Therefore, when an axial cooling air flow is formed in the cooling air passage along with the rotation of the fan, the cooling air flows into the gap formed between the axial directions of the heat radiating part, and only on the inner peripheral surface of the ring part. Each heat radiation part is exposed to cooling air.

  Thus, according to the fan motor of the fifth aspect, it is possible to expand the area of the laminated core exposed to the cooling air and sufficiently cool the laminated core and the windings attached to the laminated core. It becomes.

  First, the configuration of the fan motor 10 according to an embodiment of the present invention will be described.

  FIG. 1 is a side sectional view of a fan motor 10 according to an embodiment of the present invention, and FIG. 2 is a perspective view of a laminated core 24 used in the fan motor 10. . 3 shows a plan view of the core plate 28 constituting the laminated core 24, and FIG. 4 shows a set of core plate groups 42 formed by laminating the core plates 28. A perspective view is shown. 5 is a perspective view of the fan 18 provided in the fan motor 10 as viewed from the back side.

  A fan motor 10 according to an embodiment of the present invention shown in FIG. 1 is for cooling a radiator mounted on a vehicle such as a passenger car, and is located in the vicinity of the radiator in an engine room provided in the vehicle. Mounted on. The fan motor 10 includes a stator 12, a rotor 14, a control circuit 16, and a fan 18.

  The stator 12 includes an annular armature 20 and a disk-shaped stator housing 22. The armature 20 is configured such that a winding 26 is attached to a laminated core 24 via an insulator or the like. As shown in FIG. 2, the laminated core 24 provided in the armature 20 has a configuration in which a plurality of core plates 28 are laminated in the axial direction.

  As shown in FIG. 3, each core plate 28 includes a ring portion 30 configured in an annular shape, and teeth portions 32 extending radially outward are radially formed on the outer peripheral surface of the ring portion 30. A plurality are provided. In the present embodiment, twelve teeth portions 32 are provided on each core plate 28. In addition, a plurality (four) of convex portions 34 extending radially inward are provided on the inner peripheral surface of the ring portion 30. Further, when a line connecting the axis center 36 of the core plate 28 and the center 40 of the slot portion 38 provided between the teeth portions 32 is an imaginary line L, the convex portion 34 is formed in the radial direction of the ring portion 30. The center line extending in the direction of the line is aligned with the virtual line L.

  The laminated core 24 having a plurality of core plates 28 is manufactured and configured as follows. That is, as shown in FIG. 4, a plurality of core plates 28 (three in this embodiment) are stacked in the axial direction so that the convex portions 34 of the core plate 28 are aligned with each other in the circumferential direction. As shown in FIG. 2, a plurality of core plate groups 42 are overlapped in the axial direction so that the convex group 44 of each core plate group 42 is displaced in the circumferential direction.

  At this time, each core plate group 42 is overlapped with the core plate group 42 adjacent in the axial direction at a position shifted in the circumferential direction by 360 ° / N (the number of teeth 32 of each core plate 28). That is, in this embodiment, since the number of the teeth portions 32 of each core plate 28 is N = 12, each core plate group 42 is 360 ° / 12 = in the circumferential direction with the core plate group 42 adjacent in the axial direction. Overlapping is performed at a position shifted by 30 °. The laminated core 24 is configured in this way. In the laminated core 24, the convex portion group 44 of each core plate group 42 functions as a heat radiating portion as will be described in detail later.

  As shown in FIG. 1, the stator housing 22 includes a disk-shaped housing main body 46, and a plate thickness is provided at a position away from the center of the housing main body 46 radially outward. A cooling hole 48 penetrating in the direction is formed. A cylindrical center piece 50 is provided at the center of the housing main body 46, and the center piece 50 is inserted into a through hole 52 formed by each ring portion 30 of the laminated core 24. . The armature 20 is integrally assembled with the stator housing 22 by press-fitting the projections 44 protruding into the through holes 52 of the laminated core 24 into the center piece 50.

  Further, in the state where the armature 20 is integrally assembled to the stator housing 22 in this way, the space between the inner peripheral surface of the ring portion 30 of the laminated core 24 and the outer peripheral surface of the center piece 50 is along the axial direction. The cooling air passage 54 extends. The cooling air passage 54 is provided with a plurality of the convex group 44 described above extending radially inward from the inner peripheral surface of the ring portion 30. Furthermore, since this convex part group 44 is arrange | positioned so that it may mutually shift | deviate in the circumferential direction with the convex part group 44 of the core board group 42 adjacent to an axial direction, it is the clearance gap 56 between the axial directions of this convex part group 44. (See FIG. 2 for details).

  In addition, a pair of bearing members 58 are accommodated inside the above-described center piece 50, and the bearing members 58 support the rotary shaft 60 in a rotatable manner. One side of the rotating shaft 60 in the longitudinal direction protrudes from the hole 62 formed at the bottom of the center piece 50 to the outside of the center piece 50, and is provided on the rotor 14 at the protruding end of the rotating shaft 60. The rotor housing 64 is fixed to the central portion.

  The rotor 14 includes a bottomed cylindrical rotor housing 64, and a rotor magnet 68 is fixed to the inner peripheral surface of the cylindrical portion 66 of the rotor housing 64. The rotor magnet 68 is disposed to face the laminated core 24 provided in the armature 20 described above in the radial direction. In addition, a cooling hole 72 that penetrates in the plate thickness direction is formed in the bottom portion 70 of the rotor housing 64 at a position that is radially outward from the center portion.

  The control circuit 16 is provided integrally with the stator housing 22 and is electrically connected to the winding 26 provided on the armature 20 described above. And this control circuit 16 is comprised so that an electric current may be sent through the coil | winding 26 provided in the above-mentioned armature 20 sequentially according to the control signal output from the external control apparatus which is not shown in figure.

  The fan 18 includes a fan boss portion 74 that is integrally connected to the rotor housing 64. The fan boss portion 74 is formed in a bottomed cylindrical shape, and a plurality of blades 78 are provided radially on the outer peripheral surface of the cylindrical portion 76 of the fan boss portion 74. As the fan 18 rotates, the blade 78 forms a cooling airflow that flows from one axial side (Z1 side) of the fan motor 10 to the other axial side (Z2 side) as indicated by an arrow A. It is configured as follows.

  A plurality of auxiliary fans 80 are provided radially inside the fan boss portion 74. The auxiliary fan 80 is formed continuously from the bottom portion 82 of the fan boss portion 74 to the cylindrical portion 76. Further, as indicated by an arrow C, the auxiliary fan 80 is configured such that the cooling air discharged from the cooling hole 72 to the outside of the rotor housing 64 is inside the fan boss portion 74 and outside the rotor housing 64 as indicated by an arrow C. The cooling air flow discharged from one axial side (Z1 side) of the fan motor 10 to the other axial side (Z2 side) of the fan motor 10 is formed between the two.

  Next, the operation of the fan motor 10 according to one embodiment of the present invention will be described.

  In the fan motor 10 configured as described above, when a rotating magnetic field is applied from the armature 20 to the rotor magnet 68, the rotor 14 rotates, whereby the fan 18 rotates together with the rotor 14. When the fan 18 rotates, as indicated by an arrow A, a cooling air flow that flows from one axial side (Z1 side) of the fan motor 10 to the other axial side (Z2 side) is formed.

  Here, when the cooling air flow is formed as shown by the arrow A in this way, the other axial side (Z2 side) of the fan motor 10 becomes positive pressure, and the one axial side (Z1 side) of the fan motor 10 becomes positive. ) Is negative pressure. Accordingly, inside the fan motor 10, as indicated by an arrow B, after being sucked into the rotor housing 64 from the other axial side (Z2 side) of the fan motor 10 through the cooling hole 48, A cooling air flow that passes and is discharged from the cooling hole 72 to the outside of the rotor housing 64 is formed.

  Further, as indicated by an arrow C, the cooling air discharged from the cooling hole 72 to the outside of the rotor housing 64 by the auxiliary fan 80 provided radially inside the fan boss portion 74 and the inside of the fan boss portion 74 and the rotor. A cooling air flow discharged from one axial side (Z1 side) of the fan motor 10 to the other axial side (Z2 side) of the fan motor 10 is formed between the outside of the housing 64. Thereby, the formation of the cooling air flow indicated by the arrow B described above is assisted, and the amount of the cooling air flow is increased. Further, at this time, the cooling air sucked into the rotor housing 64 from the cooling hole 48 is a slot between the cooling air passage 54 penetrating in the axial direction in the central portion of the laminated core 24 and each tooth portion 32. 38 passes through the cooling hole 72 and is discharged out of the rotor housing 64.

  Here, in the fan motor 10 according to an embodiment of the present invention, a plurality of convex portion groups (heat dissipating portions) 44 provided in the laminated core 24 are arranged in the cooling air passage 54 described above. Moreover, since the convex group 44 is arranged so as to be displaced in the circumferential direction from the convex group 44 of the core plate group 42 adjacent in the axial direction, a gap 56 is provided between the axial direction of the convex group 44. Is formed. Accordingly, when an axial cooling air flow is formed in the cooling air passage 54 with the rotation of the fan 18, this cooling air flows into the gap 56 formed between the axial directions of the convex portion group 44, and the ring portion 30. In addition to the inner peripheral surface of the core plate group 42, the convex group 44 of each core plate group 42 is exposed to cooling air.

  As described above, according to the fan motor 10 according to the embodiment of the present invention, the area of the laminated core 24 exposed to the cooling air is expanded, and the laminated core 24 and the winding 26 mounted on the laminated core 24 are cooled. Can be sufficiently performed.

  Moreover, according to the fan motor 10 which concerns on one Embodiment of this invention, when the number of the teeth parts 32 of each core board 28 is set to N, each core board group 42 is the core board group 42 adjacent to an axial direction. They are superposed at a position shifted by 360 ° / N in the circumferential direction. Therefore, the gaps 56 can be reliably formed between the axial directions of the convex group 44 provided in the core plate group 42 by superimposing the core plate groups 42 in the axial direction in a regular arrangement. Thereby, the cooling effect of the lamination | stacking core 24 and the coil | winding 26 with which this lamination | stacking core 24 was mounted | worn can be improved reliably.

  Further, according to the fan motor 10 according to an embodiment of the present invention, an axial cooling air flow is formed in the cooling air passage 54 as the fan 18 rotates. The formation of the cooling air flow is assisted by the auxiliary fan 80 provided at 74, and the amount of cooling air flowing through the cooling air passage 54 is increased. Thereby, the cooling effect of the laminated core 24 and the winding 26 attached to the laminated core 24 can be further enhanced.

  Further, according to the fan motor 10 according to an embodiment of the present invention, the convex portion 34 has a center line that coincides with a virtual line L that connects the axial center 36 of the core plate 28 and the center 40 of the slot portion 38. Is arranged. Accordingly, in each core plate 28, the tooth portions 32 and the convex portions 34 are alternately arranged along the circumferential direction on both sides of the ring portion 30. Thereby, for example, even when the ring part 30 is configured to be narrow in the radial direction, the magnetic flux between the adjacent tooth parts 32 flows by arranging the convex part 34 between the adjacent tooth parts 32. A flow path can be comprised widely. As a result, it is possible to ensure an efficient flow of magnetic flux.

  Here, the operational effects of the present embodiment are further clarified as compared with the comparative example. FIG. 6 shows the analysis result of the heat generation state of the armature 20 according to the present embodiment and the armature according to the comparative example. 6A, the number of convex portions 44 of the core plate group 42 shown in FIG. 2 is twelve, and the laminated core 24 is configured so that all the convex portions 44 are aligned in the circumferential direction. FIG. 6B shows an analysis result of the armature 110 according to the first comparative example, in which one core plate 28 shown in FIG. 2 is configured as a set of core plate groups 42, and each core plate FIG. 6C shows the analysis result of the armature 120 according to the second comparative example in which the laminated core 24 is configured such that the convex group 44 of the group 42 is displaced in the circumferential direction. The armature according to the third comparative example in which the core plate 28 is configured as a set of core plate groups 42 and the laminated core 24 is configured so that the convex portion groups 44 of the core plate groups 42 are displaced from each other in the circumferential direction. FIG. 6D shows the analysis result of 130, that is, the analysis result of the armature 20 according to the present embodiment, that is, FIG. Analysis results of the armature 20 in which the three core plates 28 are configured as a set of core plate groups 42 and the laminated cores 24 are configured such that the convex group 44 of each core plate group 42 is displaced in the circumferential direction. It is. Moreover, in these analysis results, the temperature at the time of motor operation is so high that the shade is dark.

  As is clear from these analysis results, it can be seen that the armature 20 according to this embodiment has a higher cooling effect during motor operation than the armatures 110, 120, and 130 according to other comparative examples.

  Next, a modified example of the fan motor 10 according to one embodiment of the present invention will be described.

  In the above embodiment, twelve teeth portions 32 are provided on each core plate 28, and each core plate group 42 is shifted from the adjacent core plate group 42 in the axial direction by an angle of 360 ° / 12 = 30 ° in the circumferential direction. The laminated core 24 is configured by being overlapped at the position. In addition, the number of the teeth portions 32 is arbitrarily set (for example, 6 or 8), and the core plate groups 42 are adjacent to each other in the axial direction. The laminated core 24 may be configured by overlapping the matching core plate group 42 at a position shifted in the circumferential direction.

  Further, in the above-described embodiment, the convex portion 34 is arranged so that the center line thereof coincides with the virtual line L connecting the axial center 36 of the core plate 28 and the center 40 of the slot portion 38. Is arranged so as to be shifted in the circumferential direction from an imaginary line L connecting the axial center 36 of the core plate 28 and the center 40 of the slot portion 38 and includes at least a portion arranged on the imaginary line L. Also good.

  Moreover, in the said embodiment, although the laminated core 24 was comprised using the core board 28 of the same shape, you may comprise the laminated core 24 using a core board of a different shape.

It is side surface sectional drawing of the fan motor which concerns on one Embodiment of this invention. It is a perspective view of the lamination | stacking core used for the fan motor which concerns on one Embodiment of this invention. It is a top view of the core board which constitutes the lamination core concerning one embodiment of the present invention. It is a perspective view of a set of core board group comprised by laminating | stacking the core board which concerns on one Embodiment of this invention. It is the perspective view seen from the back side of the fan with which the fan motor concerning one embodiment of the present invention was equipped. It is a figure which shows the analysis result of the heat_generation | fever state of the armature provided in the fan motor which concerns on one Embodiment of this invention, and the armature which concerns on a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fan motor, 12 ... Stator, 14 ... Rotor, 16 ... Control circuit, 18 ... Fan, 20 ... Armature, 22 ... Stator housing, 24 ... Laminated core, 26 ... Winding, 28 ... Core plate, 30 ... Ring Part, 32 ... teeth part, 34 ... heat radiation part, 36 ... axial center, 38 ... slot part, 40 ... center, 42 ... core plate group, 44 ... convex part group (heat radiation part), 46 ... housing body part, 48, 72 ... Cooling hole, 50 ... Centerpiece, 52 ... Through hole, 54 ... Cooling air passage, 56 ... Gap, 58 ... Bearing member, 60 ... Rotating shaft, 62 ... Hole, 64 ... Rotor housing, 66 ... Cylindrical part, 68 ... Rotor magnet, 70, 82 ... Bottom, 74 ... Fan boss, 76 ... Cylindrical part, 78 ... Blade, 80 ... Auxiliary fan, L ... Virtual line

Claims (5)

An armature having a laminated core with windings attached thereto;
A center piece for supporting the armature;
A rotating shaft supported by the center piece;
A rotor supported by the rotating shaft and provided rotatably on the radially outer side of the armature;
A fan coupled to the rotor to be integrally rotatable;
In a fan motor configured with
In the laminated core, a plurality of teeth portions extending radially outward are provided radially on the outer peripheral surface of the annularly configured ring portion, and convex portions extending radially inward are provided on the inner peripheral surface of the ring portion. A plurality of core plates each having a plurality of radial configurations, and a set of core plates in which a plurality of the core plates are stacked in the axial direction so that the convex portions of the core plates are aligned with each other in the circumferential direction. And a plurality of the core plate groups are overlapped in the axial direction so that the convex group of each core plate group is displaced in the circumferential direction,
The center piece is inserted into a through-hole extending in the axial direction formed by the ring portions of the laminated core and forms a cooling air passage along the axial direction between the inner peripheral surface of the ring portions,
The fan motor is configured to form an axial cooling air flow in the cooling air passage as the fan rotates. When the number of the tooth portions of each core plate is N,
2. The fan motor according to claim 1, wherein each of the core plate groups is overlapped with a core plate group adjacent in the axial direction at a position shifted by 360 ° / N in the circumferential direction.   The convex portion of each core plate includes at least a portion disposed on an imaginary line connecting an axial center of the core plate and a center of a slot portion between the tooth portions. Item 3. The fan motor according to item 1 or item 2. The fan is provided with a fan boss part integrally connected to the rotor,
The auxiliary fan for assisting formation of the cooling air flow with the rotation of the fan is provided in the fan boss portion, according to any one of claims 1 to 3. The described fan motor. An armature having a laminated core with windings attached thereto;
A center piece for supporting the armature;
A rotating shaft supported by the center piece;
A rotor supported by the rotating shaft and provided rotatably on the radially outer side of the armature;
A fan coupled to the rotor to be integrally rotatable;
In a fan motor configured with
The laminated core has a through-hole formed in the radial center portion thereof along the axial direction, and the center piece is inserted into the through-hole so as to extend along the axial direction from the outer peripheral surface of the center piece. And a plurality of heat dissipating parts that extend toward the center piece and are spaced apart from each other in the axial direction on the inner peripheral surface of the ring part. Configured,
The fan motor is configured to form an axial cooling air flow in the cooling air passage as the fan rotates.

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