JP2016127681A - Stator for rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stator that is able to improve a rotary electric machine efficiently.SOLUTION: A stator for a rotary electric machine comprises: a stator core 20 having an annular yoke 20a and a plurality of teeth 20b projecting towards the radial inside of a stator from the yoke 20a; a stator coil 22 densely wound around the teeth 20b; and an insulator 24 interposed between the teeth 20b and the stator coil 22. At least one or more teeth 20b of the plurality of teeth 20b are partially notched, thereby forming a notch opening 36 that is open between the insulator 24 and themselves toward a rotor, and have a communication path 38 that allows communication between the notched opening 36 and a yoke-side external space and guide a coolant that has entered the notched opening 36 to a yoke-side external space.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a stator for a rotating electrical machine.

  2. Description of the Related Art Conventionally, a rotating electrical machine including a cylindrical stator around which a coil is wound and a rotor that is rotatably provided via a gap inside the stator is known. A stator of a rotating electrical machine may be configured by stacking and integrating a large number of punched magnetic plates such as electromagnetic steel plates. The stator generally has an annular yoke and teeth protruding radially inward from the yoke.

  A stator coil may be wound in concentrated winding on the teeth of the stator core. For example, Patent Document 1 below discloses a concentrated winding motor in which a cylindrical coil bobbin around which a coil is wound is inserted from the tip of a stator tooth and attached to a stator core. Usually, an insulator for insulating both the teeth and the stator coil is disposed. The insulator includes a rectangular tube-shaped tube portion that is inserted into the teeth, and a flange portion that projects outward from the base end of the tube portion.

JP2013-153615A

  In such a stator, it is common to match the outer shape of the teeth with the inner shape of the cylindrical portion of the insulator. However, for various reasons, the outer shape of the teeth and the inner shape of the cylindrical portion may be different. is there. In such a case, a gap that opens toward the inside in the radial direction may be formed between the tooth and the insulator.

  Here, in the rotating electrical machine, a cooling technology that cools the stator core and the stator coil by discharging the refrigerant supplied to the rotor to the outside in the radial direction of the rotor, that is, the stator side, using centrifugal force accompanying the rotation of the rotor. Is frequently used. When such a cooling technique is employed, if there is a gap between the teeth and the insulator, the discharged refrigerant may accumulate in the gap and stay in the gap between the stator and the rotor for a long time. . In this case, the drag retained by the gap increases drag loss, leading to a reduction in the efficiency of the rotating electrical machine.

  Therefore, an object of the present invention is to provide a stator that can further improve the efficiency of a rotating electrical machine.

  A stator of a rotating electrical machine according to the present invention includes a stator core having an annular yoke, a plurality of teeth protruding inward in the stator radial direction from the yoke, a stator coil wound around the teeth in a concentrated manner, A stator of a rotating electrical machine comprising an insulator interposed between a tooth and a stator coil, wherein at least one or more teeth of the plurality of teeth are partially missing and between the insulator and the rotor side A defect opening that opens toward the yoke, and a communication passage that communicates the defect opening with the outer space on the yoke side and guides the refrigerant that has entered the defect opening to the outer space on the yoke side. It is characterized by that.

  In a preferred aspect, the communication path is formed in the insulator. In another preferable aspect, the insulator includes a circumferential wall portion along a stator circumferential side surface of a corresponding tooth, an axial wall portion along a stator axial end surface of the corresponding tooth, the circumferential wall portion and the shaft. A corner portion that connects the directional wall portions and bends in a circular arc shape, and the one or more teeth avoid interference between the corner portions and the corner portion and form a defect opening at the corner portion. Therefore, in order to form a deficient opening between the insulator at the corner, the stator circumferential width at both ends in the stator axial direction is made smaller than the other portions, and the corner is cut off. .

  In another preferred aspect, the communication path is a through-hole extending from the surface in contact with the defect opening to the yoke-side end surface of the insulator. In another preferred aspect, the communication path is a groove formed in a square cylindrical tube portion inserted into the teeth of the insulator.

  According to the present invention, since the refrigerant that has entered the defect opening is discharged to the external space on the yoke side through the communication path, the refrigerant can be prevented from staying in the gap and drag loss can be reduced.

It is sectional drawing of the direction orthogonal to the axial direction of the rotary electric machine provided with the stator which is one Embodiment of this invention. It is a perspective view of an insulator. It is a top view in the axial direction view of one tooth. It is AA sectional drawing in FIG. It is an enlarged view of the C section in FIG. 3b. It is BB sectional drawing in FIG. It is a figure which shows the other form of a communicating path. It is a figure which shows the other form of a communicating path. It is a figure which shows the other form of a defect | deletion opening part. It is a figure which shows the other form of a defect | deletion opening part. It is a top view in the axial direction view of one tooth when the teeth width is constant over the axial direction. It is sectional drawing of the direction orthogonal to the radial direction of teeth in case the teeth width is constant over an axial direction.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments according to the present invention (hereinafter referred to as embodiments) will be described in detail with reference to the accompanying drawings. In this description, specific shapes, materials, numerical values, directions, and the like are examples for facilitating the understanding of the present invention, and can be appropriately changed according to the application, purpose, specification, and the like. In addition, when a plurality of embodiments and modifications are included in the following, it is assumed from the beginning that these characteristic portions are used in appropriate combinations.

  FIG. 1 is a cross-sectional view in a direction orthogonal to the axial direction of the rotating electrical machine 10 including the stator 12 of the present embodiment. In FIG. 1, the radial direction of the stator 12 is the radial direction, the direction along the outer periphery of the stator 12 is the circumferential direction, and the direction perpendicular to the paper surface is the axial direction.

  The rotating electrical machine 10 includes a substantially cylindrical stator 12 and a rotor 16 provided on the radially inner side of the stator 12 via a gap 14. The rotor 16 is rotatably supported by a case (not shown) that houses the rotating electrical machine 10 via a shaft 18 that is fixed at the center. Although the rotor 16 incorporating the permanent magnet 19 is shown in FIG. 1, the present invention is not limited to this, and a rotor that does not include a permanent magnet may be used.

  The stator 12 includes a stator core 20, a stator coil 22 wound around the stator core 20, and an insulator 24 that insulates the stator core 20 from the stator coil 22.

  The stator core 20 is constituted by a laminated body in which a large number of magnetic plates, for example, electromagnetic steel sheets or the like punched into a substantially annular shape are laminated in the axial direction and are integrally connected by caulking or welding, for example. The stator core 20 includes an annular yoke 20a and a plurality of teeth 20b that protrude from the radially inner side of the yoke 20a and are formed at a predetermined pitch in the circumferential direction. In the present embodiment, a stator core 20 having nine teeth 20b is illustrated.

  In the present embodiment, the teeth 20b are formed in a trapezoidal shape when viewed in the axial direction. That is, the circumferential width of the teeth 20b gradually decreases toward the tip of the teeth on the radially inner side. And the collar part which protrudes in the circumferential direction outer side is not provided in the inner diameter side front end of the teeth 20b. Thus, since the teeth 20b are formed in a trapezoidal shape that becomes narrower as they approach the tip of the teeth, there is an advantage that an attaching operation for fitting a stator coil 22 and an insulator 24, which will be described later, from the radially inner side is facilitated. is there.

  Further, between the teeth 20b adjacent in the circumferential direction, groove-like slots 21 are formed so as to open to both sides in the axial direction and radially inward. In the present embodiment, the stator core 20 having nine slots 21 that are the same number as the teeth 20b is illustrated. Further, the yoke 20a of the stator core 20 of the present embodiment is formed in a shape having a wide circumferential width at the root of the teeth 20b and a narrowest radial width at the circumferential center position of the slot 21.

  The stator coil 22 is formed by winding a coil conductor 23 such as a copper wire having an insulating film such as enamel around an insulator 24. In the present embodiment, the stator coil 22 is wound around each tooth 20b in a concentrated manner. In addition, for example, a rectangular conductor having a rectangular cross section is used as the coil conductor 23 constituting the stator coil 22 of the present embodiment. However, the coil conductor 23 is not limited to this, and a rectangular conductor having a square cross section may be used, or a round conductor having a circular cross section may be used.

  When the rotating electrical machine 10 is a three-phase AC motor, every third stator coil 22 out of the nine stator coils 22 is electrically connected by a bus bar (not shown) to form a U-phase coil. Further, every third stator coil 22 adjacent to the U-phase coil on one side in the circumferential direction is electrically connected by a bus bar (not shown) to constitute a V-phase coil. The remaining three stator coils 22 are electrically connected by a bus bar (not shown) to form a W-phase coil. One end of each phase coil thus configured is connected to each phase terminal (not shown), and the other ends are connected to each other to form a neutral point. As a result, the three-phase coils are electrically connected to form the entire stator coil 22.

  The insulator 24 has a function of electrically insulating the stator core 20 and the stator coil 22. Further, the insulator 24 may have a function of fixing the stator coil 22 to the stator core 20.

  FIG. 2 is a perspective view of the insulator 24. In FIG. 2, the direction of the stator shaft is indicated by an arrow B (the same applies to FIGS. 3b, 4 to 9, and 10b). As shown in FIG. 2, the insulator 24 is assembled to the teeth 20 b of the stator core 20, and the cylindrical tube portion 26 that houses the teeth 20 b and the radially outer end of the tube portion 26 to the outside. A protruding flange portion 28 having a rectangular frame shape is integrally provided. The flange portion 28 extends from the end portion of the cylindrical portion 26 along an outer direction orthogonal to the radial direction.

  The cylinder part 26 of the insulator 24 has a rectangular parallelepiped space 30 inside. The space 30 is formed in a shape and dimensions that can accommodate the teeth 20b of the stator core 20. An axial wall portion 26a of the cylindrical portion 26 forming the space 30 extends from the flange portion 28 along the axial end surface of the tooth 20b. Further, the circumferential wall portion 26b of the cylindrical portion 26 extends from the flange portion 28 along the circumferential side surface of the trapezoidal tooth 20b. And the corner part 27 which connects the axial direction wall part 26a and the circumferential direction wall part 26b of the cylinder part 26 is the shape curved in the substantially circular arc shape with the predetermined curvature radius r corresponding to the corner | angular part shape of the teeth 20b mentioned later. Is formed. The insulator 24 is formed with four communication passages 38 that are holes extending from the inner surface of the cylindrical portion 26 to the radially outer end surface, which will be described in detail later.

  The cylindrical portion 26 and the flange portion 28 constituting the insulator 24 can be integrally formed by injection molding with an insulating resin such as polyphenylene sulfide (PPS), for example. The thickness of the cylindrical portion 26 and the flange portion 28 of the insulator 24 is designed in consideration of the insulation between the stator core 20 and the stator coil 22 and the strength that does not cause damage during assembly or operation of the rotating electrical machine. However, it is preferable to form it as thin as possible. By forming it thin like this, it is possible to contribute to the reduction of the length of the coil conducting wire 23 constituting the stator coil 22 and the improvement of the space factor in the slot.

  3A is a plan view of one tooth 20b as viewed in the axial direction, and FIG. 3B is a cross-sectional view taken along line AA in FIG. FIG. 4 is an enlarged view of part C in FIG. 3b. FIG. 5 is a sectional view taken along line BB in FIG. As shown in FIGS. 3a and 3b, the teeth 20b of the stator core 20 in the present embodiment are formed as reduced-width teeth portions 34 in which both end portions in the axial direction (arrow B direction) have a smaller circumferential width than other portions. Yes. Specifically, the reduced width tooth portion 34 is configured such that the width of the tooth portion of at least one magnetic plate laminated on the axial end is narrow. In this embodiment, an example is shown in which the width of the teeth portion of the three magnetic plates is narrow.

  By providing the reduced-width tooth portion 34, as shown in FIG. 3b, the tooth 20b has a shape lacking four corners defined by the axial end surfaces 40 and the circumferential side surface 42. In the four corner portions, a defect opening portion 36 that opens toward the radially inner side (that is, the rotor side) is formed. And since it becomes the shape which four corners lacked in this way, interference with the corner concerned and corner part 27 of insulator 24 is avoided. Note that the radially outer end of the defect opening 36 is closed by the yoke 20a. The stator coil 22 includes at least a part of the reduced-width tooth portion 34 having a curved portion 22c that extends from a slot conductor portion 22a located in the slot 21 of the stator core 20 to a coil end portion 22b that is an axial end portion of the stator coil 22. And correspondingly.

  The curved portion 22c of the stator coil 22 will be described in detail with reference to FIG. A curved corner portion 27 of the cylindrical portion 26 of the insulator 24 is disposed so as to cover the outside of the defect opening portion 36 formed by the reduced width tooth portion 34 of the tooth 20b of the stator core 20. Here, the outer peripheral surface of the corner portion 27 of the cylindrical portion 26 is formed in an arc shape having a curvature radius r. The radius of curvature r is preferably set to be substantially equal to the radius of curvature r on the inner peripheral side of the curved portion 22c of the stator coil 22. Accordingly, there is an advantage that the stator coil 22 is stably disposed on the cylindrical portion 26 of the insulator 24 without a gap, and generation of vibration, noise, and the like can be suppressed.

  The defect opening 36 formed by the reduced width tooth portion 34 is preferably set to a ≧ b, more preferably set to a = b, where the axial dimension is a and the circumferential dimension is b. . By setting a to be greater than or equal to b, the coil conductor wire 23 connected to the coil end portion 22b through the curved portion 22c starting to bend with the curvature radius r from the slot 21 passes through a position close to the axial end surface 40 of the tooth 20b. It is because it becomes easy to make it the state wound. Further, the axial dimension a of the defect opening 36 is preferably set to be equal to or larger than the radius of curvature r of the curved portion 22c of the stator coil 22 when the thickness of the cylindrical portion 26 of the insulator 24 is not taken into consideration. More preferably. When the thickness of the cylindrical portion 26 of the insulator 24 is t, it is preferable to set a + t = r. Note that the axial dimension a of the defect opening 36 may be set larger than the curvature radius r of the curved portion 22c, and the curved portion 22c may correspond to a part of the reduced width tooth portion 34.

  Here, when the radius of curvature r of the curved portion 22c of the stator coil 22 is small, the inner peripheral side of the coil conductor 23 becomes thick, so that a gap is formed between the coil conductors 23 adjacent in the radial direction. This leads to a decrease in the rate, and the insulating film decreases on the outer peripheral side as the insulating coating extends and becomes thin. On the other hand, when the radius of curvature r is large, the coil conductor 23 extending from the slot 21 bulges outward in the axial direction, thereby increasing the coil end portion 22b. As a result, the size of the rotating electrical machine 10 is increased. It will increase in size. Therefore, the radius of curvature r of the stator coil 22 is appropriately set according to the bending rigidity of the coil conductor 23 in view of these.

  With respect to the teeth 20b of the stator core 20 configured as described above, the insulator 24 and the stator coil 22 are inserted and assembled in the radial direction from the tip of the teeth 20b. At this time, an adhesive may be attached to the outer surface of the flange portion 28 of the insulator 24 and the inner peripheral surface of the cylindrical portion 26, and the insulator 24 may be bonded and fixed to the stator core 20. In addition, the stator coil 22 may be assembled to the stator core 20 in a state where the stator coil 22 is arranged in advance on the cylindrical portion 26 of the insulator 24, or the stator coil 22 may be attached after the insulator 24 is first assembled.

  FIG. 10 shows a comparative example in which the tooth width in the AA cross section in FIG. 1 is constant over the axial direction, FIG. 10a is a plan view of one tooth as viewed in the axial direction, and FIG. It is sectional drawing of the direction orthogonal to the radial direction of the teeth 20c of a comparative example. Referring to FIG. 10, the coil conductor wire 23 constituting the concentrated winding stator coil 22 is wound so as to form a coil end portion along the axial end surface 40 of the tooth 20 c by bending from the position exiting the slot 21. It will be. At this time, when the coil conductor 23 is a rectangular conductor having a relatively high rigidity, it is necessary to make the curvature radius of the curved portion large to some extent. Therefore, the coil conductor 23 and the axial end surface of the tooth 20c at the coil end portion A gap S is formed between the two. If it does so, the line length of the coil conducting wire 23 which comprises the stator coil 22 will become long. As a result, losses such as copper loss and costs increase.

  On the other hand, in the stator 12 of the present embodiment, the reduced width tooth portions 34 are provided at both ends of the teeth 20b in the axial direction, and the defect openings 36 are formed at the corners of the teeth 20b. As a result, both of the insulator 24 and the stator coil 22 can be made to follow the teeth 20b while increasing the curvature thereof. As a result, the wire length of the coil conductor 23 can be made relatively short while suppressing damage to the insulating film of the curved portion 22c of the data coil 22. Therefore, losses such as copper loss can be suppressed correspondingly, and the cost of the stator coil 22 can be reduced, and the stator 12 and the rotating electrical machine 10 including the stator 12 can be downsized.

  By the way, in such a rotary electric machine 10, in order to cool the rotor 16 and the stator 12 efficiently, a coolant channel is formed in the shaft 18 and the rotor 16, and the coolant is supplied to the coolant channel. Yes. The refrigerant flowing in the refrigerant flow path is ejected radially outward, that is, toward the stator 12 by the centrifugal force generated as the rotor 16 rotates. The stator core 20 and the stator coil 22 are cooled by the jetted refrigerant. The refrigerant after coming into contact with the stator 12 flows out from both axial ends of the gap 14.

  Here, for efficient operation of the rotating electrical machine 10, it is desirable that the refrigerant used for cooling is discharged to the outside of the rotating electrical machine 10 as quickly as possible. This is because if the refrigerant stays in the gap 14 for a long time, drag loss increases. Here, when the deficient opening 36 is formed between the insulator 24 and the teeth 20b, there is a possibility that the refrigerant flows into the deficient opening 36 and stays there, and drag loss increases.

  Therefore, in the present embodiment, the communication path 38 is provided in the insulator 24 in order to effectively suppress the drag loss. The communication path 38 will be described with reference to FIG. 5 is a cross-sectional view taken along the line BB in FIG.

  As shown in FIG. 5, in the present embodiment, the surface of the insulator 24 that contacts the defect opening 36, specifically, the surface that contacts the yoke-side external space from the inner surface of the axial wall portion 26a, that is, the flange portion. A communication passage 38 extending linearly to the radially outer side surface 28 is formed. The communication path 38 is inclined so as to go outward in the axial direction as it approaches the outer side in the radial direction. A total of four communication paths 38 are provided, one for each defect opening 36.

  By providing the communication path 38, the refrigerant that has entered the defect opening 36 flows into the communication path 38 and is discharged to the outer space on the yoke side. As a result, it is possible to prevent the refrigerant from staying in the gap 14 for a long period of time, and as a result, drag loss can be reduced.

  In order to prevent the refrigerant from staying in the defect opening 36, the defect opening 36 itself may be closed instead of forming the communication path 38. For example, it is conceivable that the corner portion 27 of the cylindrical portion 26 of the insulator 24 is formed thick so as to fill the defect opening 36. With this configuration, the defect opening 36 is eliminated, and the refrigerant can be prevented from staying in the defect opening 36. However, in this case, although the material of the insulator 24 increases unnecessarily, the contact area between the refrigerant and the teeth 20b decreases, so that the cooling efficiency of the teeth 20b and the stator coil 22 decreases. On the other hand, since the contact area between the teeth 20b and the refrigerant increases if the defect opening 36 is formed between the insulator 24 and the teeth 20b as in this embodiment, the teeth 20b and the teeth 20b are wound around. The stator coil 22 can be effectively cooled. Further, since the outlet for discharging the refrigerant to the outside is provided not only at both ends of the gap 14 in the axial direction but also at the insulator 24, the refrigerant can be discharged to the outside more quickly, and drag loss can be reduced.

  The configuration of the communication path 38 described here is an example, and the configuration is not particularly limited as long as the defect opening 36 and the outer space on the yoke side can communicate with each other. Therefore, the communication path 38 may use a space formed between the groove formed by cutting the thickness of the radially outer end of the cylindrical portion 26 of the insulator 24 and the stator 12 as the communication path 38. For example, as shown in FIG. 6, a step-shaped groove is formed by cutting the cylindrical portion 26 of the insulator 24 so that the radially outer end thereof is thin, and the groove is interposed between the groove 12 and the stator 12. The formed space may be used as the communication path 38. Further, the shape of the groove is not limited to the step, and may be a tapered shape as shown in FIG. In this case, the inner surface of the cylindrical portion 26 may be cut so as to become thinner as it approaches the radially outer end so that it becomes a tapered surface. Further, one communication path 38 may be configured by combining holes and grooves formed in the insulator 24. In any case, it is possible to prevent the output performance of the rotating electrical machine from being deteriorated by forming the communication path 38 that connects the defective opening 36 and the yoke-side external space not in the yoke 20a but in the insulator 24.

  However, depending on the thickness and shape of the insulator 24, the communication path 38 having a sufficiently large size may not be formed in the insulator 24. In that case, a through hole or a groove may be formed in a part of the yoke 20 a to form the communication path 38. When the communication path 38 is formed in the yoke 20a, it is desirable to form the position and shape so as not to obstruct the magnetic path as much as possible.

  In the present embodiment, the defect opening 36 is formed at the corner of the tooth 20b, but the defect opening 36 may be formed at another part. For example, as shown in FIG. 8, a reduced-width tooth portion having a smaller axial width than other portions is provided at the circumferential center of the tooth 20b, and a defect opening 36 is formed at both axial ends of the tooth 20b and at the circumferential center. May be. As another form, as shown in FIG. 9, you may provide the reduced-width tooth | gear part whose circumferential direction width | variety becomes smaller than another part in the height position which is different in the right and left of the teeth 20b. Even in the case of FIGS. 8 and 9, the communication path 38 that communicates the defect opening 36 and the outer space on the yoke side may be formed in the insulator 24 or the yoke 20 a. Furthermore, the defect opening 36 does not need to extend to the yoke 20a, and may be closed in the middle of the radial direction. In any case, the cooling efficiency of the stator core 20 and the stator coil 22 can be improved by forming the defect opening 36. If the communication passage 38 that connects the defective opening 36 and the outer space on the yoke side is formed, drag loss can be reduced and the efficiency of the rotating electrical machine can be further improved.

  DESCRIPTION OF SYMBOLS 10 Rotating electrical machine, 12 Stator, 14 Gap, 16 Rotor, 18 Shaft, 19 Permanent magnet, 20 Stator core, 20a Yoke, 20b, 20c Teeth, 21 Slot, 22 Stator coil, 23 Coil conductor, 24 Insulator, 26 Tube part, 27 Corner portion, 28 flange portion, 30 space, 34 reduced width tooth portion, 36 missing opening portion, 38 communication path, 40 axial end surface, 42 circumferential side surface.

Claims (5)

A stator core having an annular yoke and a plurality of teeth protruding inwardly in the stator radial direction from the yoke;
A stator coil wound with concentrated winding around the teeth;
An insulator interposed between the teeth and the stator coil;
A stator of a rotating electric machine comprising:
At least one or more teeth among the plurality of teeth are partially chipped to form a defect opening portion that opens toward the rotor side with the insulator,
Further, a communication path is provided that communicates the defect opening and the yoke-side external space, and guides the refrigerant that has entered the defect opening to the yoke-side external space.
A stator for a rotating electrical machine. A stator for a rotating electrical machine according to claim 1,
The stator of a rotating electrical machine, wherein the communication path is formed in the insulator. A stator for a rotating electrical machine according to claim 1 or 2,
The insulator connects the circumferential wall portion along the stator circumferential side surface of the corresponding tooth, the axial wall portion along the stator axial end surface of the corresponding tooth, and the circumferential wall portion and the axial wall portion. A corner portion curved in an arc shape,
The one or more teeth should avoid the interference between the corner portion and the corner portion, and form a defect opening portion at the corner portion between the insulator and the insulator. The stator circumferential width at both ends in the stator axial direction is made smaller than the other parts, and the corners are cut off.
A stator for a rotating electrical machine. A stator for a rotating electrical machine according to any one of claims 1 to 3,
The stator of a rotating electrical machine, wherein the communication path is a through hole that extends from a surface of the insulator in contact with the defect opening to the end surface on the yoke side. A stator for a rotating electrical machine according to any one of claims 1 to 3,
The stator of a rotating electrical machine, wherein the communication path is a groove formed in a rectangular tube-shaped tube portion inserted into the tooth of the insulator.

Images