JPH06205550A - Stator core of rotary electric machine - Google Patents

Abstract

PURPOSE:To prevent shaft voltage due to the effects of a narrow magnetic path region formed by a ventilation hole provided behind the slot of stator iron core of a rotatory electric apparatus. CONSTITUTION:An opening groove 5 for loading an armature coil is provided at the internal circumference of an iron core 4, shapes of narrow magnetic path 7 are formed with an equal interval for total circumference and the number of narrow magnetic path is set to 8 or its multiple. As explained above, generation of shaft voltage can be suppressed by making symmetry the magnetic fluxes crossing the axis.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stator (armature) core of a rotary electric machine such as an induction machine, and more particularly to improvement of a shape corresponding to a magnetic path.

[0002]

2. Description of the Related Art FIG. 4 is a sectional front view showing a structure of a stator core of a conventional rotating electric machine. In the figure, 1 is an iron core portion which is formed by laminating circular thin steel plates to an appropriate thickness to form a stator iron core, and 2 is opened on the inner peripheral side of the iron core portion 1 to accommodate an armature winding (not shown). The grooves 3 and 3 are ventilation holes that penetrate the core portion 1 in the axial direction at six positions on the back of the groove 2 at equal intervals over the entire circumference.

Next, the operation will be described. A magnetic flux is generated by a current flowing through an armature winding (not shown) inserted in the groove 2 to form a magnetic field with the stator core and the rotor core as loops. At this time, in the magnetic path of the stator core, when the magnetic field passes in the vicinity of the place where the ventilation holes 3 are provided, that is, when the magnetic field passes through the narrow magnetic path, the magnetic path is narrowed and the magnetic flux density is increased. If there is such a factor that changes the magnetic resistance on the side of the stator core, the magnetic flux interlinking with the shaft becomes asymmetric due to the number of parts that become the magnetic resistance, here the number of ventilation holes 3 and the number of poles, and axial voltage is generated.

[0004]

The stator core of the conventional rotary electric machine is constructed as described above and provided without relating the number of ventilation holes penetrating the back of the groove, that is, the number of narrow magnetic paths, to the axial voltage. Therefore, there is a problem that a large shaft voltage is likely to be generated in correspondence with the number of poles, and it is necessary to provide shaft current prevention insulation with a bearing or the like.

The present invention has been made in order to solve the above problems, and is for fixing a rotary electric machine which prevents an axial voltage generated due to a narrow magnetic path region formed by a ventilation hole provided in a stator core. The purpose is to obtain a child iron core.

[0006]

A stator core of a rotary electric machine according to the present invention has an opening groove for mounting an armature winding on an inner peripheral side of an iron core portion, and a narrow magnetic path in a back portion at equal intervals around the entire circumference. A region shape is formed and the number of the narrow magnetic path regions is 8 or a multiple of 8.

[0007]

The stator core of the rotating electric machine according to the present invention is 8
Alternatively, the number of narrow magnetic path regions, which is a multiple of 8, makes the magnetic flux linking the axis symmetrical, and does not generate the axial voltage.

[0008]

EXAMPLES Example 1. Embodiment 1 of the present invention will be described below with reference to the drawings. 1 is a sectional front view showing the structure of a stator core of a rotary electric machine according to Embodiment 1 of the present invention. In the figure, reference numeral 4 is an iron core portion that is formed by laminating circular thin steel plates to an appropriate thickness to form a stator iron core, and 5 is opened on the inner peripheral side of the iron core portion 4 to accommodate an armature winding (not shown). The grooves 6 are ventilation holes penetrating the iron core portion 4 in the axial direction at equal intervals on the back of the groove 5, and are provided at 8 or multiples of 8 in this case. Reference numeral 7 denotes a narrow magnetic path region of the iron core portion 4 having the ventilation holes 6.

Next, the operation will be described. The number of ventilation holes 6 of the iron core part 4 is set to 8 or a multiple of 8 so as to be evenly spaced around the entire circumference, so that the narrow magnetic path region 7 having a high magnetic flux density in the magnetic field of the iron core part 4 is evenly multiplied by 8 or 8 over the entire circumference. It will be placed in several places,
In principle, if the corresponding pole number is other than 16 poles or a multiple of 16 poles, all magnetic fluxes interlinking with the axis in the magnetic field are symmetrical and no axial voltage is generated. This is the number of narrow magnetic path areas, that is, ventilation holes 6
When n is the number of poles and p is the number of fractions, when the number of numerator that reduces fraction n / p is an odd number, the magnetic flux that intersects the axis becomes asymmetric and the axial voltage is generated, and when the number is even, it is symmetrical and the axial voltage is generated. It can be judged by not having it.

Embodiment 2. Although the narrow magnetic path region 7 is formed by the ventilation holes 6 in the first embodiment, as shown in FIG. 2, the outer shape of the core 8 is octagonal or a multiple of 8 and the narrow magnetic path region 8 is formed.
Alternatively, the shape may be a multiple of 8. Further, the shape may be such that grooves 10 for cooling are provided at equal intervals on the outer periphery as illustrated.

Embodiment 3. Further, in the second embodiment, the laminated iron core portion has a configuration in which all the outer shapes are aligned, but as shown in FIG. 3, each of the quadrangular plates is arranged in a circumferential direction of 45 degrees so that the main shape is an octagon. It may be configured to. Note that a plurality of these may be stacked to form a multiple of 8 such as a hexagon.

[0012]

As described above, according to the present invention, the inner peripheral side of the iron core portion has the opening groove for mounting the armature winding, and the shape of the narrow magnetic path region is formed in the back portion at equal intervals over the entire circumference. Moreover, since the number of the narrow magnetic path regions is set to 8 or a multiple of 8, there is an effect that the magnetic flux interlinking with the shaft is made symmetrical and the stator core of the rotating electric machine in which the axial voltage does not occur can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional front view showing a configuration of a stator core of a rotary electric machine according to a first embodiment of the present invention.

FIG. 2 is a sectional front view showing a configuration of a stator core of a rotary electric machine according to a second embodiment of the present invention.

FIG. 3 is a sectional front view showing a configuration of a stator core of a rotary electric machine according to Embodiment 3 of the present invention.

FIG. 4 is a sectional front view showing a configuration of a stator core of a conventional rotating electric machine.

[Explanation of symbols]

 4 Iron core part 5 Groove 6 Vent hole 7 Narrow magnetic path area

Claims (2)

[Claims] 1. A fixing of a rotating electric machine, comprising an opening groove for mounting an armature winding on an inner peripheral side of a laminated iron core, and forming a narrow magnetic path region shape at equal intervals over the entire circumference on a back portion of the opening groove. In the child core, the number of the narrow magnetic path regions is 8 or a multiple of 8, and the stator core of the rotating electric machine is characterized. 2. The stator core of a rotating electric machine according to claim 1, wherein the narrow magnetic path region is formed between the ventilation hole penetrating in the axial direction, the outer periphery of the laminated core and the opening groove.