JPH0851738A - Stator for motor - Google Patents

Abstract

PURPOSE:To obtain a stator for motor in which a laminated stator core can be provided with an oblique slot for placing a winding with no influence on the profile. CONSTITUTION:A stator 10 comprises a laminated stator core 12 and an exciting winding 14. The laminated stator core 12 comprises an outer laminated core 20 having substantially cylindrical inner wall 18 extending axially, and an inner laminated core 22 secured to the inner wall 18 while being contained in the outer laminated core 20. The inner laminated core 22 is formed by laminating a plurality of thin plate cores punched from a thin magnetic plate into a predetermined shape, in the axial direction while turning each core relatively by a predetermined angle in one direction. Consequently, a plurality of tooth parts 38 arranged radially while inclining in the axial direction within the outer core 20, and a part 40 for coupling the tooth parts 38 at the radial inner fringe parts thereof at a constant interval in the circumferential direction, are formed in the inner core 22 and an oblique slot 46 for placing an exciting winding 14 is formed between the tooth parts 38.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stator of an electric motor, and more particularly to a laminated stator core formed by laminating a plurality of magnetic thin plates in an axial direction and having a plurality of slots on a surface surrounding a rotor, and a plurality of laminated stator cores. And an excitation winding installed in the slot of the electric motor.

[0002]

2. Description of the Related Art For example, in an induction motor or a synchronous motor used as a drive source for rotating or feeding a main shaft of a machine tool, a plurality of slots extending in the axial direction are provided on the surface of a stator core facing a rotor, It is known to have a stator having excitation windings installed in these slots. In such a stator, magnetic flux passes through the air gaps between the rotor facing end faces of the plurality of teeth of the stator core that define the slots and the rotor surface. In order to reduce (torque ripple), a stator having a so-called diagonal slot extending obliquely with respect to the axial direction is widely adopted in electric motors that require high operating accuracy.

When providing the above-mentioned slanted slots in a laminated stator core composed of a laminated body of a plurality of magnetic thin plates, first, a thin plate core having a plurality of teeth is stamped and formed from a magnetic thin plate material such as a silicon steel plate. Next, the plurality of thin plate cores are relatively rotated so that the teeth of the adjacent thin plate cores are slightly displaced in one direction by a predetermined angle, are laminated in the axial direction, and are fixed to each other by caulking or bonding. In this way, the plurality of teeth that are stacked slightly offset by a predetermined angle form a plurality of tooth portions of the laminated stator core that extend obliquely with respect to the axial direction, and diagonal slots are formed between the tooth portions.

[0004]

When forming the slanted slots in the laminated stator core, since a plurality of thin plate cores are relatively rotated and laminated as described above, for example, when the outer peripheral portion of the thin plate core has a polygonal shape. The outer shape of the laminated stator core has a shape obtained by twisting the originally expected polygonal column shape in the circumferential direction, which not only impairs the appearance but also makes the handling of the electric motor inconvenient. If the outer peripheral portion of the thin plate core is formed into a circular shape to form a cylindrical laminated stator core, such a problem is eliminated, but the outer shape of the laminated stator core is limited thereby to a cylindrical shape. Such limitation of the outer shape of the laminated stator core directly affects the outer shape of the electric motor. For example, it is difficult to design the outer shape according to the usage environment of the electric motor, or another outer shape may provide added value and additional effects in design. There is a problem that it becomes a bottleneck when doing.

Further, a stator structure using a plurality of rod members axially penetrating a plurality of thin plate cores for integrally fastening and supporting the laminated stator core is known.
In such a structure, when the slanted slots are formed in the laminated stator core by the above method, the rod holes provided in the thin plate cores are connected obliquely to the axial direction due to the lamination, which makes it difficult to insert and fasten the rod member. Challenges arose. An object of the present invention is to provide a stator of an electric motor including a laminated stator core made of a laminated body of magnetic thin plates, and to wind the laminated stator core without affecting the outer shape of the laminated stator core or the shape of the through hole of the thin plate core fastening rod member. An object of the present invention is to provide a stator that can be provided with a diagonal slot for installation.

[0006]

In order to achieve the above object, the present invention relates to a laminated stator core which is formed by laminating a plurality of magnetic thin plates in the axial direction and has a plurality of slots on a surface surrounding a rotor, In a stator of an electric motor including an excitation winding installed in a plurality of slots of a laminated stator core, the laminated stator core includes an outer laminated core having an inner wall defining a hollow portion penetrating in the axial direction and a hollow outer laminated core. The inner laminated core is housed in a hollow portion and fixed to the inner wall, and the inner laminated core includes a plurality of tooth portions radially arranged in the hollow portion with an inclination with respect to the axial direction and surrounding the tooth portions at predetermined intervals. A stator for an electric motor, wherein each of the plurality of slots is defined between adjacent teeth of the inner laminated core and extends obliquely with respect to the axial direction. To.

[0007]

The plurality of tooth portions of the inner laminated core are fixedly supported at predetermined intervals in the circumferential direction by the connecting portion, and are radially arranged so as to be inclined with respect to the axial direction. Such an inner laminated core axially rotates a thin plate core having a plurality of teeth and a connector punched out of a magnetic thin plate material so that each tooth is slightly displaced in one direction by a predetermined angle. It is formed by stacking and fixing. At this time, the teeth of the inner laminated core inclined with respect to the axial direction are formed by the plurality of teeth that are slightly shifted by a predetermined angle, and the excitation winding is provided between the plurality of teeth supported by the connecting portion. The slot for installing the wire is formed to be inclined with respect to the axial direction. The slanted slots formed in this manner remove harmonic components of the magnetic flux between the stator and the rotor, and reduce uneven rotation (torque ripple) of the rotor.

The outer laminated core, which is formed separately from the inner laminated core, can be formed by laminating a plurality of thin plate cores having a predetermined outer peripheral shape so that the contours of the thin plate cores are exactly overlapped with each other. The desired outer shape of the laminated stator core can be obtained. When a rod member for fastening a thin plate core is used, if the insertion hole of the rod member is provided in the outer laminated core, the insertion hole extends parallel to the axis without being affected by the formation of the diagonal slot. Set up.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a preferred embodiment of the present invention. In each drawing, the same or similar components are designated by common reference numerals. Referring to the drawings, FIG. 1 is an exploded view of a stator 10 of an electric motor according to an embodiment of the present invention, and FIG. 2 is a stator 10 of FIG.
Is shown in the assembled state. The stator 10 includes a laminated stator core 12 and an excitation winding 14. The laminated stator core 12 has an outer laminated core 20 having a substantially cylindrical inner wall 18 defining a hollow portion 16 penetrating in the axial direction of the stator 10.
And the inner wall 1 accommodated in the hollow portion 16 of the outer laminated core 20.
And an inner laminated core 22 fixed to No. 8.

The outer laminated core 20 is a thin plate core 24 (FIG. 3) punched from a magnetic thin plate material such as a silicon steel plate into a predetermined shape.
(See (a), (b)) is formed by stacking a plurality of layers in the axial direction. The thin plate core 24 is a flat plate element having an inner peripheral portion 26 having a substantially circular contour and an outer peripheral portion 28 having a substantially square contour concentric with the inner peripheral portion 26. The outer laminated core 20 is formed by closely laminating a plurality of thin plate cores 24 in the axial direction so that the inner peripheral portions 26 and the outer peripheral portions 28 of the plurality of thin plate cores 24 accurately overlap with each other. Adjacent thin plate cores 24 are fixed to each other by a method such as caulking or bonding. The inner peripheral portion 26 and the outer peripheral portion 28 of each thin plate core 24 are overlapped with each other, so that the outer laminated core 20 is provided with the substantially cylindrical inner wall 18 and the substantially regular prismatic outer wall 30.

The inner laminated core 22 is made of a magnetic thin plate material such as a silicon steel plate and punched into a predetermined shape.
(See (a), (b)) is formed by stacking a plurality of layers in the axial direction. The thin plate core 32 fixedly fixes a plurality of teeth 34 having a substantially rectangular contour radially arranged at equal intervals in the circumferential direction and a tooth 34 extending in the circumferential direction from the radially inner edge of each tooth 34 and adjacent to each other. It is a flat plate element provided with a substantially annular connector 36 to be connected. The inner laminated core 22 has an adjacent thin plate core 32.
The plurality of thin plate cores 32 are formed by closely laminating in the axial direction while relatively rotating so that the connector 36 of each of them accurately overlaps each other and the teeth 34 slightly overlap each other by a predetermined angle in one direction. To be done. Adjacent thin plate cores 32 are fixed to each other by a method such as caulking or bonding as described later.

Due to the overlapping of the teeth 34 of the thin plate cores 32 and the connector 36, a plurality of radial arrangements are formed in the inner laminated core 22 in the hollow portion 16 of the outer laminated core 20 with an inclination with respect to the axial direction. Tooth portions 38 and the tooth portions 38
And a connecting portion 40 that connects the inner peripheral portion of the inner peripheral portion at equal intervals in the circumferential direction (see FIGS. 1 and 5A and 5B). Further, the connecting portion 40 is provided with an inner wall 42 that extends in a substantially cylindrical shape in the axial direction, and the inner wall 42 is used as the inner wall 42.
And a rotor (not shown) incorporated therein to face each other through a gap. Further, the radial outer peripheral surfaces 44 of the plurality of tooth portions 38 are preferably arranged on a cylindrical surface concentric with the inner wall 42 of the connecting portion 40.

In this way, the inner laminated core 22 is formed with the slots 46 for installing the exciting windings 14 between the plurality of tooth portions 38 supported by the connecting portions 40, which are inclined with respect to the axial direction. It This diagonal slot 46 presenting a so-called closed slot shape in the laminated stator core 12
Removes harmonic components of the magnetic flux between the stator 10 and the rotor (not shown), and reduces uneven rotation (torque ripple) of the rotor during operation of the electric motor.

When assembling the stator 10, as shown in FIG. 1, after the winding 14 made of, for example, a die-wound coil is attached to each tooth portion 38 of the inner laminated core 22, the inner laminated core 22 is moved to the outer laminated core. The outer peripheral surface 44 in the radial direction of each tooth portion 38 of the inner laminated core 22 is fixed to the inner wall 18 of the outer laminated core 20. This fixing can be performed by a method such as interference fitting by press fitting, adhesion with an adhesive, fixing with a resin mold, or the like, but in the radial direction of the inner laminated core 22 so as not to affect the magnetic circuit formed in the laminated stator core 12. The outer peripheral surface 44 and the inner wall 18 of the outer laminated core 20 are preferably in close contact with each other. In this way, the stator 10 shown in FIG. 2 is assembled. The winding 14 is not limited to the die-wound coil shown in the figure, and may be directly wound around each tooth portion 38 manually or by a machine, and may be wound in various forms such as a single-layer winding or a double-layer winding. The wires can be attached to the inner laminated core 22. At this time, in the illustrated embodiment, the slot 46 provided in the inner laminated core 22 is opened to the outside, so that the winding 14 can be mounted very easily.

The connecting portion 40 of the inner laminated core 22 is preferably formed as thin as possible in order to reduce magnetic leakage between the adjacent tooth portions 38. Generally, the thin plate core 32 is
Although it has a thickness of 0.5 mm to 3.0 mm, the connector 36 of the thin plate core 32 can have a radial dimension up to about the same as the thickness of the thin plate core 32 by the punching process. Therefore, the connecting portion 40 of the inner laminated core 22 can be formed to have a thickness (radial dimension) of 0.5 mm by laminating the thin plate cores 32 having a thickness of 0.5 mm. If desired, the inner wall 42 of the connecting portion 40 may be subjected to mechanical processing such as grinding to further reduce the thickness of the connecting portion 40.

In the stator 10 having the above structure, the laminated stator core 12 has the outer laminated core 20 and the inner laminated core 2.
Since the plurality of thin plate cores 32 forming the inner laminated core 22 are relatively rotated and laminated to define the oblique slots 46, the outer wall 30 of the outer laminated core 20 is formed by combining the two. It is possible to maintain the originally expected regular square columnar shape.

Outer laminated core 20 and inner laminated core 22
Can be manufactured by, for example, one progressive die apparatus capable of performing various work processes by designating a desired press station. According to the progressive die apparatus, the punching work of the thin plate core from the magnetic thin plate material and the stacking and fixing work of the plurality of thin plate cores are automatically performed in a desired order. Particularly, when manufacturing the inner laminated core 22, the work of laminating the thin plate cores 32 while relatively rotating them by a predetermined angle and fixing the adjacent thin plate cores 32 to each other by caulking is performed.
It is easily done by progressive die equipment. FIG. 5B shows the caulking portion 48 formed on each tooth 34 of the thin plate core 32 by the caulking operation.

Alternatively, the caulking operation described above can be omitted by laminating thin plate cores punched from magnetic thin plate materials having adhesives applied to both sides in advance. In this case, a plurality of thin plate cores 32 of the inner laminated core 22 can be laminated while relatively rotating by a predetermined angle by using a substantially cylindrical jig 50 as shown in FIG. The jig 50 is a thin plate core 3
A substantially cylindrical inner wall 52 that evenly contacts the respective teeth 34 of 2 is provided, and the inner wall 52 extends at an angle with respect to the axial direction.
One ridge 54 is formed. When forming the inner laminated core 22, while contacting the tip side surface portion of one tooth 34 of the thin plate core 32 with the shoulder portion formed between the inner wall 52 of the jig 50 and the protrusion 54, A plurality of thin plate cores 32 may be laminated. The inner laminated core 22 is formed by applying heat and pressure to the plurality of laminated thin plate cores 32 and fixing them.

The stator according to the present invention can have various shapes other than the above. For example, the outer laminated core 20
The contour of the outer wall 30 is adapted to the desired outer shape of the electric motor, such as a shape obtained by cutting out the four corners of a regular square pole as shown in FIG. 7A or another polygonal column shape as shown in FIG. 7B. It can be shaped as desired. In that case, the contour of the outer wall 30 of the outer laminated core 20 is such that the diagonal slot 46 is formed in the inner laminated core 22.
It is not affected by forming (FIG. 5) and is determined by the contour of the outer peripheral portion 28 (FIG. 3) of the thin plate core 24. Note that FIG. 7A shows a plurality of holes 56 penetrating the outer laminated core 20 in the axial direction. These holes 56
This is for inserting a rod member (not shown) integrally fixedly supporting the plurality of thin plate cores 24 of the outer laminated core 20. In the conventional stator, when the diagonal slots are formed in the laminated stator core, the rod member insertion holes are also inclined, but according to the stator according to the present invention, the diagonal slots 46 are formed in the inner laminated core 22. However, since the hole 56 provided in the outer laminated core 20 extends linearly in parallel to the axis as shown in the drawing, it is not difficult to insert the rod member.

Further, as shown in FIGS. 8 (a) and 8 (b),
A plurality of tooth portions 58 arranged radially in the hollow portion 16 (FIG. 1) of the outer laminated core 20 with an inclination with respect to the axial direction, and the tooth portions 58 are circumferentially equidistantly spaced at their radial outer edges. It is also possible to use the inner laminated core 62 including the connecting portion 60 for connecting. The inner laminated core 62 is shown in FIG.
As shown in (b), a plurality of teeth 64 having a substantially rectangular contour arranged radially at equal intervals in the circumferential direction, and a tooth 64 extending in the circumferential direction from the outer peripheral edge of each tooth 64 and adjacent to each other. It is formed by stacking a plurality of thin plate cores 68 each having a substantially annular connector 66 that is fixedly connected in the axial direction. At this time, the thin plate cores 68 are adjacent to each other.
The connector 66 of the above is accurately laminated without being displaced from each other and the teeth 64 are slightly displaced in one direction by a predetermined angle so as to be overlapped with each other, and the teeth are closely laminated in the axial direction while rotating relative to each other. Fixed to each other. In this way, in the inner laminated core 62, the slots 70 for installing the excitation windings 14 (FIG. 1) are formed between the plurality of tooth portions 58 supported by the connecting portion 60 so as to be inclined with respect to the axial direction. To be done.

Radial inner peripheral surfaces 72 of the plurality of teeth 58 of the inner laminated core 62 are arranged on one cylindrical surface and face a rotor (not shown) incorporated in the stator 10 with a gap. Further, the connecting portion 60 is preferably provided with each tooth portion 58.
Is provided with an outer wall 74 that is concentric with the radially inner peripheral surface 72 and that extends in a substantially cylindrical shape in the axial direction. The outer wall 74 is press-fitted onto the inner wall 18 of the outer laminated core 20 and adhered and fixed by an adhesive, a resin mold, or the like. . Further, on the radially inner peripheral surface 72 of each tooth portion 58, a projecting edge portion 76 extending in the circumferential direction from both side surfaces of the tooth portion 58 is formed. The projecting edge portion 76 prevents the exciting winding 14 arranged in the slot 70 from coming off from the slot 70.

In the inner laminated cores 22 and 62, the tooth portion 3
The shapes and the number of 8, 58 are arbitrary and can be set according to the magnetic characteristics required of the electric motor. However, the connecting portion 40
The inner wall 42 and the inner peripheral surface 72 of the tooth portion 58 in the radial direction face the rotor through a gap, and therefore it is important that they are arranged on one cylindrical surface concentric with the rotor rotation axis.
It is important that the radial outer peripheral surface 44 of the tooth portion 38 and the outer wall 74 of the connecting portion 60 are also arranged on one cylindrical surface so that the shape does not change due to the rotation when the thin plate cores 32 and 68 are laminated. is there.

[0023]

As is apparent from the above description, according to the present invention, in a stator of an electric motor having a laminated stator core formed of a laminated body of magnetic thin plates, the laminated stator core is formed by a combination of an outer laminated core and an inner laminated core. Then, the inner laminated core is provided with a plurality of tooth portions radially arranged to be inclined with respect to the axial direction and a connecting portion that connects the tooth portions in the circumferential direction at predetermined intervals, and thus is adjacent to the inner laminated core. The diagonal slots are defined between the teeth. Therefore, the outer shape of the laminated stator core, that is, the outer shape of the outer laminated core is not affected by defining the oblique slots in the inner laminated core, and is formed into a desired contour. Further, if the outer laminated core is provided with an insertion hole for the rod member for fastening the thin plate core, the insertion hole is extended parallel to the axis without being affected by the formation of the oblique slot. As described above, according to the present invention, there is provided a high-performance electric motor having a desired outer shape suitable for a use environment and having a wide application range capable of reducing rotor rotation unevenness during operation.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a stator of an electric motor according to an embodiment of the present invention.

FIG. 2 is a perspective view of the stator shown in FIG. 1 when assembled.

3A and 3B are diagrams of a thin plate core that constitutes an outer laminated core of the stator of FIG. 1, and FIG. 3A is a plan view and FIG. 3B is a perspective view.

4A and 4B are diagrams of a thin plate core forming the inner laminated core of the stator of FIG. 1, and FIG. 4A is a plan view and FIG. 4B is a perspective view.

5 is a diagram of an inner laminated core of the stator of FIG. 1, (a)
It is a top view and (b) perspective view.

6 is a perspective view showing a jig for forming an inner laminated core of the stator shown in FIG. 1. FIG.

FIG. 7 is a perspective view of a stator having an outer laminated core according to a modified example, showing an outer laminated core having (a) a shape in which four corners of a regular square pole are cut out, and (b) a polygonal prism shape.

FIG. 8 is a diagram of an inner laminated core according to a modified example, including (a) a plan view and (b) a perspective view.

9A and 9B are views of a thin plate core forming the inner laminated core of FIG. 8, and FIG. 9A is a plan view and FIG. 9B is a perspective view.

[Explanation of symbols]

 12 ... Laminated stator core 14 ... Excitation winding 16 ... Hollow part 18 ... Inner wall 20 ... Outer laminated core 22, 62 ... Inner laminated core 24, 32, 68 ... Thin plate core 30, 74 ... Outer wall 34, 64 ... Teeth 36, 66 ... Connector 38, 58 ... Tooth portion 40, 60 ... Connecting portion 46, 70 ... Slot 50 ... Jig

Claims (1)

[Claims] 1. A laminated stator core, which is formed by laminating a plurality of magnetic thin plates in an axial direction and has a plurality of slots on a surface surrounding a rotor, and an excitation winding installed in the plurality of slots of the laminated stator core. In a stator of an electric motor comprising: an outer laminated core having an inner wall defining a hollow portion penetrating in an axial direction; and an outer laminated core housed in the hollow portion of the outer laminated core and fixed to the inner wall. The inner laminated core includes a plurality of tooth portions radially arranged in the hollow portion so as to be inclined with respect to the axial direction, and a connecting portion connecting the tooth portions in the circumferential direction at a predetermined interval. A stator of an electric motor, wherein each of the plurality of slots is defined between the adjacent tooth portions of the inner laminated core and extends at an angle with respect to an axial direction.