JP2019216523A - Motor stator and motor including the same - Google Patents

Abstract

To provide a motor stator for suppressing a reduction in efficiency and a motor including the same.SOLUTION: The motor stator includes: a cylindrical stator core 16; a stator winding; and a pair of iron core end plates 24 arranged on both ends of the stator core in an axial direction. The stator core has an annular yoke unit and a plurality of stator teeth 20 extending from an inner peripheral surface of the yoke unit. Each of the iron core end plates 24 has an annular outer peripheral unit 24a arranged by overlapping the yoke unit and a plurality of end plate teeth 24b, extending from an inner peripheral surface of the outer peripheral unit toward a center of the outer peripheral unit, which are respectively arranged on the stator teeth. Each of the end plate teeth has a plane area B smaller than a plane area A of the stator teeth. Distances D between extended ends of the end plate teeth and extended ends of the stator teeth are set to 0 to 5 mm.SELECTED DRAWING: Figure 3

Description

  FIELD Embodiments described herein relate generally to an electric motor stator and an electric motor including the same.

Generally, an electric motor is provided with a stator having a substantially cylindrical stator core and a rotor winding wound around the stator core, and a motor disposed at a radial center of the stator core, and rotating with respect to the stator core. A freely provided rotor. The stator core is often formed by stacking a plurality of electromagnetic steel sheets. With this configuration, the eddy current generated in the stator core can be suppressed.
In an electric motor, stator core end plates (hereinafter, referred to as end plates) are provided on both axial sides of a stator core. By sandwiching the stator core between these end plates, the end portions of the electromagnetic steel plate are prevented from peeling off during the manufacture of the stator. In general, a metal plate such as iron, which is thicker than an electromagnetic steel plate, is used for the end plate from the viewpoint of rigidity.

  Iron core retainers are further provided on both axial sides of the stator iron core and the end plate. The plurality of electromagnetic steel plates and the end plates are sandwiched between the iron core holders to prevent the electromagnetic steel plates from being separated. When an electric motor is fixed to a member to be fixed such as a railway car, for example, the stator core is supported by the casing via a core holder. Then, the casing is fixed to the fixed member.

JP 2003-274579 A JP 2008-301674 A

In the electric motor configured as described above, since the end plate is in close contact with the stator core, the magnetic flux generated in the stator core leaks to the end plate. Since the end plate is formed to be thicker than the electromagnetic steel plate, a change in magnetic flux in the end plate generates an eddy current, which may reduce the efficiency of the motor.
The problem to be solved by the present invention is to provide a stator for an electric motor capable of suppressing a decrease in the efficiency of the electric motor and an electric motor including the stator.

  According to the embodiment, the stator of the electric motor includes a cylindrical stator core, a stator winding, and a pair of core end plates arranged at both ends in the axial direction of the stator core. I have. The stator core is formed by stacking a plurality of electromagnetic steel sheets, and has an annular yoke portion, extending from the inner peripheral surface of the yoke portion toward the center of the yoke portion, and extending in a circumferential direction of the yoke portion. And a plurality of stator teeth provided at intervals. Each of the core end plates extends from the inner peripheral surface of the annular outer peripheral portion and the inner peripheral surface of the outer peripheral portion arranged toward the yoke portion toward the center of the outer peripheral portion, and extends in the circumferential direction of the outer peripheral portion. A plurality of end plate teeth which are provided at intervals from each other and are arranged so as to overlap the stator teeth. Each of the end plate teeth has a plane area smaller than the plane area of the stator teeth, and a distance between an extended end of the end plate teeth and an extended end of the stator teeth is formed to be 0 to 5 mm. ing.

FIG. 1 is a sectional view showing an electric motor for a railway vehicle according to the first embodiment. FIG. 2 is a perspective view showing a stator core and an end plate of the electric motor according to the first embodiment. FIG. 3 is a plan view showing the stator teeth of the stator core and the end plate teeth of the end plate. FIG. 4 is an exemplary perspective view showing a stator core and an end plate of an electric motor according to a second embodiment; FIG. 5 is a plan view showing stator teeth of the stator core and end plate teeth of an end plate of the electric motor according to the second embodiment. FIG. 6 is a perspective view showing a stator core and an end plate of a motor according to a third embodiment. FIG. 7 is a plan view showing stator teeth of the stator core and end plate teeth of an end plate of the electric motor according to the third embodiment. FIG. 8 is a plan view showing stator teeth and end plate teeth of the electric motor according to the fourth embodiment. FIG. 9 is a plan view showing stator teeth and end plate teeth of the electric motor according to the fifth embodiment. FIG. 10 is a plan view showing stator teeth and end plate teeth of the electric motor according to the sixth embodiment.

  Hereinafter, various embodiments will be described with reference to the drawings. It is to be noted that the same reference numerals are given to the same components throughout the embodiment, and the overlapping description will be omitted. In addition, each drawing is a schematic diagram for promoting understanding of the embodiment and its understanding, and its shape, dimensions, ratio, and the like are different from those of an actual device. The design can be appropriately changed.

(1st Embodiment)
FIG. 1 is a cross-sectional view of the electric motor for a railway vehicle according to the first embodiment, and shows only one half on one side around a center axis C1. FIG. 2 is a perspective view showing a stator core and an end plate of the motor, and FIG. 3 is a plan view showing teeth of the stator core and the end plate.
As shown in FIG. 1, the electric motor 10 is configured as, for example, an inner rotor type permanent magnet synchronous motor. The electric motor 10 includes an annular or cylindrical stator 12, a rotor 14 supported inside the stator 12 so as to be rotatable around a central axis C <b> 1 and coaxial with the stator 12, And a casing 30 that supports the rotor 14.
In the following description, the extending direction of the central axis C1 is referred to as the axial direction, the direction rotating about the central axis C1 as the circumferential direction, and the direction orthogonal to the axial direction and the circumferential direction as the radial direction.

  As shown in FIGS. 1 and 2, the stator 12 includes a cylindrical stator core 16 and a rotor winding 18 wound around the stator core 16. The stator core 16 is configured by concentrically laminating a number of annular magnetic steel sheets 17 made of a magnetic material, for example, silicon steel. A plurality of slots 22 are formed in the inner periphery of the stator core 16. The plurality of slots 22 are arranged at equal intervals in the circumferential direction. Each slot 22 opens in the inner peripheral surface of the stator core 16 and extends radially from the inner peripheral surface. Each slot 22 extends over the entire axial length of the stator core 16. By forming the plurality of slots 22, the inner peripheral portion of the stator core 16 forms a plurality (for example, 36 in this embodiment) of stator teeth 20 protruding toward the central axis C1. The stator teeth 20 are arranged at equal intervals along the circumferential direction. As described above, the stator core 16 integrally includes the annular yoke portion 16a and the plurality of stator teeth 20 projecting radially from the inner peripheral surface of the yoke portion toward the central axis C1. . The multiple electromagnetic steel plates 17 are connected to each other in a stacked state by welding a plurality of portions on the outer peripheral surface of the stator core 16.

  As shown in FIG. 1, the rotor windings 18 are embedded in the plurality of slots 22 and are wound around the stator teeth 20. The rotor windings 18 are provided so as to overhang from both axial ends of the stator core 16 toward the outside in the axial direction. By passing an alternating current through the rotor winding 18, a predetermined linkage magnetic flux is formed in the stator 12 (stator teeth 20).

As shown in FIGS. 1 and 2, core end plates (hereinafter, referred to as end plates) 24 having substantially the same cross-sectional shape as the stator core 16 are provided at both axial ends of the stator core 16, respectively. . Further, an iron core retainer 26 is provided on these end plates 24.
The end plate 24 is configured by stacking a plurality of metal plates, for example, 1.6 mm thick iron plates, which are set to be larger than the thickness of the electromagnetic steel plate 17 from the viewpoint of securing rigidity. Each end plate 24 has an annular outer peripheral portion 24a corresponding to the yoke portion 16a of the stator core 16, and a plurality of end plate teeth 24b projecting radially from the inner peripheral surface of the outer peripheral portion 24a toward the central axis C1. And are integrally provided. The end plate teeth 24b are arranged at equal intervals along the circumferential direction. The end plate 24 is arranged coaxially with the stator core 16, the outer peripheral portion 24a is arranged so as to overlap the yoke portion 16a, and the plurality of end plate teeth 24b are arranged so as to overlap the stator teeth 20, respectively. . The plurality of iron plates constituting the end plate 24 are connected to each other by, for example, spot welding at the position of the end plate teeth 24b.

As shown in FIGS. 2 and 3, the end plate teeth 24 b are formed to have a size smaller than that of the stator teeth 20 so as not to contact the rotor winding 18. For example, the circumferential width W2 of the end plate teeth 24b is smaller than the circumferential width W1 of the stator teeth 20 (W2 <W1). The radial length of the end plate teeth 24 b is equal to or less than the radial length of the stator teeth 20. Thereby, the distance D between the extending end of the end plate teeth 24b and the extending end of the stator teeth 20 is set to about 0 to 5 mm.
Further, in this embodiment, each end plate tooth 24b has a slit 40 extending in the radial direction. Here, the slit indicates an opening or a slit formed penetrating from one surface of the end plate 24 to the opposite surface. The slit 40 extends from the base end (the end on the outer peripheral portion 24a side) of the end plate teeth 24b to the extension end, and opens at the extension end. When the plane area of the end face of the stator teeth 20 (the surface area of the stator teeth 20 when the stator core 16 is viewed from the axial direction) is A, and the plane area of the end plate teeth 24b is B, A> B. , B / A = about 0.5 to 0.9.

  As shown in FIG. 1, the iron core retainer 26 is formed in a substantially annular shape by a metal such as iron. The inner diameter of the iron core retainer 26 is such that the stator iron core retainer 18 and the stator winding 18 do not come into contact with each other. The stator core 16 and the end plate 24 are sandwiched and held from both sides in the axial direction by a pair of iron core holders 26. The iron core presser 26 is arranged to face the yoke 16 a of the stator iron core 16 and the outer peripheral portion 24 a of the end plate 24. The iron core retainer 26, the end plate 24, and the stator iron core 16 are connected to each other and integrated by welding or the like.

  The casing 30 includes a substantially cylindrical first bracket 32a attached to an iron core retainer 26 located on the driving end side of the stator core 16, and a bowl-shaped first bracket 32a attached to the iron core retainer 26 located on the non-drive end side. And two brackets 32b. The first and second brackets 32a, 32b are formed of, for example, an aluminum alloy or the like. An annular bearing bracket (first bearing housing) 34 is coaxially fastened to the distal end side of the first bracket 32a with a bolt. At the center of the bearing bracket 34, for example, a first bearing portion 36 incorporating a roller bearing 35 is fastened as a first bearing. A second bearing portion 38 having a built-in ball bearing 37 as a second bearing is fastened to the center of the second bracket 32b.

On the other hand, the rotor 14 has a cylindrical shaft (rotating shaft) 42 rotatably supported about the central axis C1 by the first and second bearing portions 36 and 38, and a substantially central portion of the shaft 42 in the axial direction. And a plurality of permanent magnets 46 embedded in the rotor core 44. The rotor core 44 is configured as a laminated body in which a number of magnetic materials, for example, annular electromagnetic steel plates 47 such as silicon steel are concentrically laminated. The rotor core 44 has an inner hole 50 formed coaxially with the central axis C1. The shaft 42 is inserted and fitted into the inner hole 50, and extends coaxially with the rotor core 44. When the shaft 42 is inserted into the rotor core 44, the rotor core 44 and the shaft 42 are integrated by shrink fitting or press fitting.
The rotor core 44 is coaxially arranged with a small gap (air gap) inside the stator core 16. That is, the outer peripheral surface of the rotor core 44 faces the inner peripheral surface of the stator core 16 (the distal end surface of the stator teeth 20) with a slight gap. In the present embodiment, the axial length of the rotor core 44 corresponds to the total axial length of the stator core 16 and the pair of end plates 24. Thus, the rotor core 44 faces the inner peripheral surfaces of the stator core 16 and the pair of end plates 24.

  A plurality of magnet embedding holes 52 penetrating in the axial direction are formed in the rotor core 44. A permanent magnet 46 is loaded and arranged in each magnet embedding hole 52, and is fixed to the rotor core 44 by, for example, an adhesive. Each permanent magnet 46 extends over the entire length of the rotor core 44. The plurality of permanent magnets 46 are arranged at predetermined intervals in the circumferential direction of the rotor core 44.

At both ends in the axial direction of the rotor core 44, a substantially disk-shaped magnetic shielding plate 54 and a rotor core retainer 56 are provided. The magnetic shielding plate 54 is formed of a non-magnetic material such as stainless steel. The rotor core holder 56 is formed of a metal such as iron. Each of the magnetic shielding plate 54 and the rotor core retainer 56 has a through-hole at the center, and the shaft 42 is inserted or press-fitted into these through-holes.
The pair of rotor core retainers 56 are arranged so that the laminated electromagnetic steel plates 47 (rotor core 44) and the magnetic shielding plate 54 are not separated from each other, and are not displaced in the axial direction with respect to the shaft 42. It is sandwiched and held. The rotor core retainer 56 is set to a sufficient thickness so as to secure rigidity.

In the electric motor 10 configured as described above, when the rotor winding 18 is energized, a magnetic flux is formed in the stator core 16. This magnetic flux passes through the rotor core 44 via the stator teeth 20. Then, the rotor 14 rotates by the interaction with the magnetic flux by the permanent magnet 46.
Here, the stator core 16 is integrated with core holders 26 arranged via end plates 24 provided at both ends in the axial direction, and is further supported by a casing 30 via these core holders 26. For this reason, the magnetic flux formed in the stator core 16 passes through the end plate 24 and the end plate teeth 24b, and at that time, an eddy current may be induced in the end plate teeth 24b. However, in the present embodiment, the slits 40 are provided in the end plate teeth 24b, and the eddy currents flowing in the circumferential direction are shielded and suppressed as much as possible by the slits 40. For this reason, the motor loss caused by the eddy current can be reduced, and the stator and the electric motor 10 having excellent driving efficiency can be obtained.
Further, according to the present embodiment, the plane area B of the end plate teeth 24b is smaller than the plane area A of the stator teeth 20, and is set to 50 to 80% of the plane area A in one example. By making the plane area B smaller than the plane area A, it is possible to further suppress the generation of eddy current.

  Next, a description will be given of a stator of an electric motor according to another embodiment and a modification. In other embodiments and modifications described below, the same parts as those in the above-described first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted or simplified. This will be described in detail focusing on the differences.

(Second Embodiment)
The stator of the electric motor according to the second embodiment will be described.
FIG. 4 is a perspective view showing a stator core and a core end plate of the electric motor according to the second embodiment, and FIG. 5 is a plan view showing teeth of the stator core and the core end plate.
As shown, according to the second embodiment, each end plate tooth 24b has a plurality of slits, for example, two slits 40a and 40b. The slits 40a, 40b extend in the radial direction from the base end to the front end of the end plate teeth 24b. The slits 40a and 40b are arranged at intervals in the circumferential direction of the end plate teeth 24b. The slits 40a and 40b are open at the extended ends of the end plate teeth 24b. The radial length of the end plate teeth 24b is shorter than the radial length of the stator teeth 20 by an interval D (0 to 2 mm). In the present embodiment, the width W2 of the end plate teeth is substantially equal to the width W1 of the stator teeth 20. The plane area B of the end plate teeth 24b is smaller than the plane area A of the stator teeth 20 (A> B), and B / A = about 0.5 to 0.8.

  In the second embodiment configured as described above, the magnetic flux is shielded by the plurality of slits 40a and 40b provided in the end plate teeth 24b, and the eddy current induced in the end plate teeth 24b is suppressed. it can. At the same time, by making the plane area B of the end plate teeth 24b smaller than the plane area A of the stator teeth 20, generation of eddy currents can be further suppressed. For this reason, the motor loss caused by the eddy current is reduced, and a stator and a motor having excellent driving efficiency can be obtained.

(Third embodiment)
The stator of the electric motor according to the third embodiment will be described.
FIG. 6 is a perspective view showing a stator core and a core end plate of the electric motor according to the third embodiment, and FIG. 7 is a plan view showing teeth of the stator core and the core end plate.
As shown, according to the third embodiment, each end plate tooth 24b has a plurality of slits, for example, five slits 40. The slits 40 extend in the circumferential direction of the end plate teeth 24b, and are arranged at predetermined intervals in the radial direction. Each slit 40 is formed at the center in the width direction of the end plate teeth 24b, and both ends in the circumferential direction are closed without opening.
The radial length of the end plate teeth 24b is shorter than the radial length of the stator teeth 20 by an interval D (for example, 0.5 mm). In the present embodiment, the width W2 of the end plate teeth 24b is formed slightly smaller than the width W1 of the stator teeth 20. By providing the plurality of slits 40, the plane area B of the end plate teeth 24b is smaller than the plane area A of the stator teeth 20 (A> B), and B / A = about 0.5 to 0.8. Have been.

  Also in the third embodiment configured as described above, the magnetic flux is shielded by the plurality of slits 40 provided in the end plate teeth 24b, and the eddy current induced in the end plate teeth 24b can be suppressed. At the same time, by making the plane area B of the end plate teeth 24b smaller than the plane area A of the stator teeth 20, generation of eddy currents can be further suppressed. For this reason, the motor loss caused by the eddy current is reduced, and a stator and a motor having excellent driving efficiency can be obtained.

(First modification)
The stator of the electric motor according to the first modification will be described.
FIG. 8 is a plan view showing the stator core and the teeth of the core end plate of the electric motor according to the first modification.
As shown, according to the first modification, the end plate teeth 24b are formed to have a minimum necessary width in order to prevent the stator teeth 20 from peeling off. In one example, the width W2 in the wind direction of the end plate teeth 24b is formed to be about 30 to 50% of the width W1 of the stator teeth 20. The radial length of the end plate teeth 24b is shorter than the radial length of the stator teeth 20 by an interval D (for example, 1 mm). As a result, the plane area B of the end plate teeth 24b is smaller than the plane area A of the stator teeth 20, and B / A = about 0.3 to 0.5.
According to the first modified example, the end plate teeth 24b are sufficiently narrower than the stator teeth 20, so that the magnetic flux formed on the stator core 16 is prevented from leaking to the end plate teeth 24b as much as possible. Can be. Thereby, the eddy current induced in the end plate 24 is reduced.

(Second modification)
The stator of the electric motor according to the second modification will be described.
FIG. 9 is a plan view showing the stator core and the teeth of the core end plate of the electric motor according to the second modification.
As illustrated, according to the second modification, the end plate teeth 24b have a plurality of slits, for example, four slits 40. The slits 40 extend in the circumferential direction of the end plate teeth 24b and are arranged at predetermined intervals in the radial direction. Each slit 40 is formed at the center in the width direction of the end plate teeth 24b, and one end in the circumferential direction is opened at a side edge of the end plate teeth 24b. As a result, the end plate teeth 24b have a comb shape.
The radial length of the end plate teeth 24b is shorter than the radial length of the stator teeth 20 by an interval D (for example, 1 mm). The width W2 of the end plate teeth 24b is formed smaller than the width W1 of the stator teeth 20. By providing the plurality of slits 40, the plane area B of the end plate teeth 24b is smaller than the plane area A of the stator teeth 20 (A> B), and B / A = about 0.5 to 0.8. Have been.

(Third Modification)
The stator of the electric motor according to the third modification will be described.
FIG. 10 is a plan view showing the stator core and the teeth of the core end plate of the electric motor according to the third modification.
As shown, according to the third modification, the end plate teeth 24b have a plurality of slits, for example, four slits 40. The slits 40 are arranged in a line in the radial direction of the end plate teeth 24b, and extend at predetermined intervals in the radial direction.
The radial length of the end plate teeth 24b is shorter than the radial length of the stator teeth 20 by an interval D (for example, 1 mm). The width W2 of the end plate teeth 24b is formed smaller than the width W1 of the stator teeth 20. By providing the plurality of slits 40, the plane area B of the end plate teeth 24b is smaller than the plane area A of the stator teeth 20 (A> B), and B / A = about 0.5 to 0.8. Have been.

  According to the second modified example and the third modified example, the magnetic flux is shielded by the plurality of slits 40 provided in the end plate teeth 24b, and the eddy current induced in the end plate teeth 24b can be suppressed. At the same time, by making the plane area B of the end plate teeth 24b smaller than the plane area A of the stator teeth 20, generation of eddy currents can be further suppressed. For this reason, the motor loss due to the eddy current can be reduced, and a stator and a motor having excellent driving efficiency can be provided.

Although some embodiments and modifications of the present invention have been described, these embodiments and modifications are presented as examples, and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and modified examples are included in the scope and gist of the invention, and are also included in the invention described in the claims and their equivalents.
For example, the slit of the end plate teeth is not limited to a fixed width and a straight line, but may be a curved or bent slit. The width of the slit need not be constant. Further, the slit is not limited to the band shape, and may have another shape such as a circle, an ellipse, and a polygon.
The size, material, shape, and the like of the rotor are not limited to the above-described embodiment, but can be variously changed according to the design. The rotor and the electric motor according to the present embodiment can be applied not only to a permanent magnet field motor but also to an induction motor.

10 ... motor, 12 ... stator, 14 ... rotor, 16 ... stator core,
18 ... stator winding, 20 ... stator teeth, 22 ... slot, 24 ... iron core end plate,
24a: outer peripheral portion, 24b: end plate teeth, 26: iron core retainer, 30: casing,
40, 40a, 40b ... slit, 42 ... shaft, 44 ... rotor core,
46 ... permanent magnet

Claims (5)

A stator of an electric motor comprising: a cylindrical stator core, a stator winding, and a pair of core end plates disposed on both ends in the axial direction of the stator core,
The stator core is formed by laminating a plurality of electromagnetic steel plates, and has an annular yoke portion, extending from the inner peripheral surface of the yoke portion toward the center of the yoke portion, and extending in a circumferential direction of the yoke portion. A plurality of stator teeth provided at intervals from each other,
Each of the iron core end plates extends toward the center of the outer peripheral portion from the inner peripheral surface of the annular outer peripheral portion and the outer peripheral portion arranged so as to overlap with the yoke portion, and extends in the circumferential direction of the outer peripheral portion. A plurality of end plate teeth provided at intervals from each other and arranged so as to overlap the stator teeth,
Each of the end plate teeth has a plane area smaller than a plane area of the stator teeth, and a distance between an extended end of the end plate teeth and an extended end of the stator teeth is formed to be 0 to 5 mm. Is a stator.   The stator according to claim 1, wherein a circumferential width of the end plate teeth is smaller than a circumferential width of the stator teeth.   The stator according to claim 1, wherein each of the end plate teeth has a single or a plurality of slits, and the slits extend in a radial direction or a circumferential direction of the end plate teeth.   The circumferential width of the end plate teeth is 30 to 50% of the circumferential width of the stator teeth, and the plane area of the end plate teeth is 30 to 50% of the plane area of the stator teeth. The stator according to claim 1, wherein the stator is formed. A stator according to any one of claims 1 to 4,
A rotor having a shaft coaxially disposed with the stator and rotatably supported, and a rotor core attached to the shaft and opposed to the stator with a gap inside the stator.
An electric motor comprising:

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