JPS5922464B2 - Gap winding rotating electric machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gap winding rotating electric machine, and particularly to a structure of a laminated stator core.

Generally, in a gap winding rotating electric machine, the coil is fixedly held on the inner circumferential surface of the stator core, but in order to receive the rotational force acting on the coil on as large a surface as possible during this fixing, to relieve stress concentration. The inner peripheral surface of the stator core is polygonal.

That is, as shown in FIG. 1, the elastic insulator 1 is inserted so that the outer peripheral surface of the shaped and pulled coil 1 is engaged with the recess 2' formed by the polygonal inner peripheral surface of the stator core 2. ' is formed in a convex shape, and the structure is such that the rotational force acting on the coil 1 is transmitted to the inner peripheral surface of the iron core 2 due to their engagement.In addition, the insulating ring 3 protects against the force acting in the inner radial direction. Coil 1 is fixed.

Note that 4 in the figure is a spacer that also serves as a damper against the electromagnetic force acting on the coil 1.

By the way, in such a structure, since the inner circumferential surface of the stator core 2 is polygonal, unlike a general rotating electric machine where the inner circumferential surface of the stator core is circular, the outer circumferential surface of the rotor magnetic poles The distance between the stator core and the inner peripheral surface of the stator core, that is, the air gap length, pulsates at a frequency of the product nf of the angular number n of the core inner peripheral surface and the armature frequency f corresponding to the rotation speed of the rotor magnetic poles.

For example, in the case of a two-pole machine with a regular pentagonal core inner peripheral surface as shown in Fig. 2, when the excited magnetic pole 5 is in the position shown in Fig. 2 a, most of the various magnetic fluxes will pass through the magnetic pole. In the direction of the arrow, φ1. It becomes φ2.

Here, if the radial width of the stator core is set to allow sufficient magnetic flux to pass through, the magnetic circuit through which the clockwise magnetic flux φ2 passes will have an air gap length with higher magnetic resistance than the magnetic circuit through which the counterclockwise magnetic flux φ1 passes. Since it is a dog, when one circuit around the rotor shaft 6 is considered, a counterclockwise magnetic flux as shown by the arrow 11a remains.

Next, when the rotor rotates by one corner of the inner peripheral surface of the stator core and reaches the position shown in Figure 2, the clockwise magnetic flux φ1 becomes larger than the counterclockwise magnetic flux φ, and the rotor shaft 6 The residual magnetic flux surrounding the circle rotates clockwise as shown by the arrow 11b, i.e.,
As the residual magnetic flux surrounding the rotor shaft 6 rotates,
It alternates at a frequency nf, which is the product of the armature frequency f and the number of angles n of the inner circumferential surface of the stator core.

Therefore, this residual magnetic flux generates a voltage at both ends of the rotor shaft 6, and this voltage is applied to the bearings supporting the rotor at both ends.

If the oil film of the bearing is broken by that voltage, the rotor shaft 6, one bearing 7, the base 8, the other bearing 7, and the path 9 returning to the rotor shaft 6, as shown in FIG. Current will flow.

In the figure, 10 indicates the direction of the magnetic flux surrounding the rotor shaft 6.

This phenomenon occurs not only in two-pole machines but also in four-pole machines as shown in FIG. 4.

In addition, residual magnetic flux may be generated by iron core segments as well.

In the following description, stator coils, which are not particularly relevant to the description of the present invention, are not illustrated.

In other words, as shown by the broken line in FIG. 4, when the thin iron plate constituting the stator core 2 is punched into a plurality of segments 2', a slight gap g is created at the seam of each segment 2'. Since the magnetic resistance at this point increases, the magnetic resistance of each magnetic circuit becomes unbalanced, and a magnetic flux surrounding the rotor shaft 6 is generated, and this gap g also causes the same phenomenon as described above. The limit that causes this phenomenon is that the effective value of the shaft voltage is 1, Ov.
In the above case, it is said that the bearing will be damaged in about one week to one year, and if the shaft current flows at an effective value of 2 A/current, damage will appear after 5 hours of operation.

In other words, when a shaft current flows, most of the energy is used to destroy the oil film on the bearing surface, so local melting of the bearing metal occurs and the bearing cannot be avoided from overheating and melting, rendering it inoperable. I will be entering.

In this way, in a stator core with segments with a polygonal inner circumference, axial voltage is likely to occur due to the variation factor of the air gap length that controls the magnetic resistance of the magnetic circuit, that is, the relationship between the number of corners on the inner circumference and the number of divided segments. Although there is a drawback, if the magnetic resistance is uniform in the circumferential direction of each stator core, no axial voltage will occur.
It is difficult to determine the specific means to achieve uniformity, which is a major problem with this type of rotating electric machine.

The present invention has been made in view of this problem, and its purpose is to prevent the rotor from collapsing even if the stator core is segment-shaped and the cross-sectional shape of the inner peripheral surface is polygonal. It is an object of the present invention to provide a rotating electrical machine of this type in which the magnetic flux surrounding the shaft is not biased and generation of shaft voltage due to this can be prevented.

In order to achieve this object, the present invention sets the number of angles of the polygon on the inner circumferential surface of the stator core and the number of gaps formed between the adjacent segmented iron plates to be an integral multiple of the number of rotor magnetic poles. At the same time, it is characterized in that the circumferential positions of the gaps are equally spaced and the gaps are formed to have the same size all around the circumference.

An embodiment of the present invention will be described below with reference to FIG.

In this embodiment, the inner circumferential surface of the stator core 2 has a square shape that is an integral multiple of the number of poles of the rotor magnetic poles 5; in this case, since it is a four-pole machine, the inner circumferential surface of the stator core 2 has a regular octagonal shape that is one integral multiple of the number of poles. It is formed.

In other words, it is always point symmetrical with respect to the rotor magnetic axis d.

That is, no matter where the rotor is located, each portion of the inner circumferential surface of the stator core 2 divided by the rotor magnetic axis d is formed to be point symmetrical about the rotor axis 6. There is.

Further, the thin iron plate constituting the stator core 2 is punched into segments 2' divided at equal intervals in the circumferential direction, and the number of segments 2', that is, the number of gaps g, is The number of poles is an integral multiple of 4, for example, 4, and the circumferential position of the gap g is the same on the entire circumference, and the width of the gap is also formed equally on the entire circumference.

That is, no matter where the rotor is located, each of the four magnetic circuits is configured to have the same number, position, and size of gaps.

Therefore, when the rotor magnetic pole 5 is in the position shown in Fig. 5a, if the air gap length of the magnetic circuit through which the counterclockwise magnetic flux φ passes is (δ2 + δ1), then Due to symmetry, not only the air gap length of the magnetic circuit through which the clockwise magnetic flux φ2 passes is (δ1 + δ2), but also these stator core magnetic circuits are naturally equal, and each magnetic circuit has an equal number ( In this case, a gap g of 1) is included, and both magnetic fluxes φ1. The magnetic resistance of each magnetic circuit with respect to φ2 is balanced and the magnetic flux is unbalanced, so that no magnetic flux surrounding the rotor shaft 6, which causes shaft voltage, is generated.

Furthermore, even when the rotor magnetic poles 5 come to the position shown in FIG. 5, both magnetic fluxes φ1. The air gap lengths of each magnetic circuit through which φ2 passes are equal to (δ4 + δ3) and (δ3 + δ4), respectively, and each magnetic circuit includes the same number and thick gaps g, so the rotation is similarly performed. No magnetic flux is generated surrounding the child shaft 6.

As explained above, according to the present invention, the number of angles of the polygon on the inner circumferential surface of the stator core and the number of gaps formed between the adjacent segmented iron plates are each an integral multiple of the number of rotor magnetic poles. In addition, since the circumferential positions of the gaps are equally spaced and the gaps are of equal size, the inner circumferential surface of the stator core is polygonal and the stator core is divided into multiple segments in the circumferential direction. Even in a gap-winding rotating electrical machine, the magnetic resistance in each magnetic circuit is always equal regardless of the rotor's magnetic pole position, and rotation can be performed using the same operations and processes as before, without using any special equipment or equipment. 0, which can sufficiently prevent the generation of shaft voltage due to bias in the magnetic flux surrounding the child shaft.

[Brief explanation of drawings]

Fig. 1 is an enlarged sectional view showing a part of the stator of a gap-winding rotating electric machine; Figs. 2a and b are schematic front views of a conventional two-pole gap-winding rotating electric machine with different rotor magnetic pole positions; Figure 3 is a schematic side view of a gap-winding rotating electrical machine to explain the path through which the shaft current flows, Figure 4 is a schematic front view of a conventional four-pole gap-winding rotating electrical machine, and Figures 5a and b each show the rotor. 1 is a schematic front view of a gap winding rotating electric machine according to an embodiment of the present invention in which magnetic pole positions are different. FIG. 1...Stator coin, 2...Stator core, 2'...Segment, 5...Rotor magnetic pole, g... Gaps between segments.

Claims (1)

[Claims] 1. A stator core in which a plurality of segment-shaped steel plates divided in the circumferential direction are stacked in a staggered manner, and the cross-sectional shape of the inner circumferential surface thereof is polygonal, and the stator core is held and fixed to the inner circumferential surface of this stator core. In a gap-winding rotating electric machine including a stator coil and rotor magnetic poles rotating inside the stator coil, a gap winding is formed between the polygonal corners of the inner peripheral surface of the stator core and the adjacent segment-shaped iron plates. A gap winding rotation characterized in that the number of gaps is an integral multiple of the number of poles of the rotor magnetic poles, the circumferential position of the gaps is equally spaced, and the gap size is the same all around the circumference. Electric machine.