JPS627765B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a salient pole rotor in which a magnetic pole core provided with two dovetails is attached to a spider boss.

In the case of a salient pole rotor in a rotating electric machine, such as a water turbine generator, when the rotor is large and has a large capacity, two dovetails are provided on the magnetic pole core and attached to a spider boss, and this spider boss is sometimes provided with radial ventilation ducts. .

The main parts of a conventional salient pole rotor of this kind are shown in FIGS. 1 and 2 in a plan sectional view and a side sectional view. 1 is a spider rim fixedly supported on the outer circumference of a rotor spider (not shown);
Rim plates made of thin steel plates are laminated and tightened together with tightening bolts 2. 3 is a spacer tube inserted between the laminated layers, thereby forming a radial ventilation duct 4. 5 is a pair of dovetail slots provided at each magnetic pole core mounting position on the outer periphery of the spider rim 1; 6 is a magnetic pole core; a pair of dovetails 7 provided at the bottom are inserted into the dovetail slots 5; A dovetail key 9 is driven in and fixedly supported. The magnetic pole core 6 is formed by laminating core plates and tightening them together with a tightening bolt 8. 10 is a field coil attached to the magnetic pole core 6.

In recent years, the capacity of water turbine generators has been increasing rapidly, and as a result, the length of the magnetic pole core 6 has become longer and longer, and the number of ventilation ducts 4 of the spider rim 1 in the axial direction has increased. The spider rim 1 forms a yoke that serves as a magnetic path between adjacent magnetic pole cores 6, but since the ventilation duct 4 is a space, the magnetic path cross-sectional area of the magnetic flux from the magnetic pole core 6 is small in this part. The magnetic resistance was increasing. This is due to the following reason. The magnetic flux of the rotor enters the spider rim 1 in the radial direction from the magnetic pole core 6,
It passes through this spider rim in the circumferential direction and enters the adjacent magnetic pole core 6. This magnetic flux does not pass through the ventilation duct 4 due to the low magnetic permeability of air, but passes through the spider rim 1 as shown by the dotted arrow in FIG. The magnetic pole core 6 and the spider rim 1 are made of laminated steel plates, and have high magnetic permeability and extremely low magnetic resistance. However, since it is a laminated steel plate, there are minute irregularities on the contact surfaces of both magnetic paths, so complete contact is not achieved, and the magnetic resistance at this contact surface increases. Therefore, the larger the contact area between the magnetic pole core 6 and the spider rim 1, the more the magnetic resistance can be reduced, but in the ventilation duct 4, the spider rim 1 is a blank space and is not in contact with it.
Due to the ventilation ducts 4 at many locations, a problem has arisen in which the magnetic flux value decreases and the required value cannot be obtained. In order to eliminate this, magnetic pole core 6 and spider rim 1
The length of the iron core had to be increased, resulting in a larger external length and higher price.

Further, as shown in FIG. 1, when the rotor rotates in the direction of arrow A, the spider rim 1 is inserted into the ventilation duct 4.
Cooling air enters from the inner diameter side as shown by arrow B, passes below the dovetail 7 of the magnetic pole core 6, and flows between adjacent field coils 10 as shown by arrow D. A vortex C of cooling air is generated in the space between the pair of dovetails 7 of the ventilation duct 4, and ventilation resistance increases. Especially in the case of multiple poles, the greater the number of ventilation ducts, the greater the effect, and the greater the degree of reduction in air volume.

In this invention, in the ventilation duct part of the spider rim,
Insert a piece of magnetic filling between the dovetails of each pair,
In addition to increasing the cross-sectional area of the magnetic path in the ventilation duct between the magnetic pole core and the spider rim, we also increased the contact area of the magnetic path between the two to increase the magnetic flux value. The purpose is to reduce losses.

3 and 4 are a plan sectional view and a side sectional view showing essential parts of a salient pole rotor according to an embodiment of the present invention, and numerals 1 to 10 are similar to the conventional device described above. 20 is ventilation duct 4 of spider rim 1
A magnetic filler piece is inserted between a pair of dovetails 7 at the bottom and abuts the bottom of the magnetic pole core 6, and is fixed by being sandwiched between the pair of dovetails 7 and the dovetail keys 9 on both sides. The magnetic filler piece 20 is shown in perspective view in FIG. The magnetic filling piece 20 has a top surface 20a in contact with the bottom surface of the magnetic pole core 6, both side surfaces 20b in contact with the dovetail keys 9 on both sides, and both end surfaces 20c in contact with the end surfaces of the spider rim 1 in the ventilation duct 4. . The space into which this magnetic filler piece 20 is inserted is a dead end point in terms of ventilation, and by inserting this magnetic filler piece 20, the vortex of the cooling air is eliminated and the circulation is improved. That is, as shown in FIG. 3, the cooling air that enters the ventilation duct 4 from the inner diameter side of the spider rim 1 as shown by arrow B passes below the dovetail 7 of the magnetic pole core 6 and the magnetic filler 20 without creating a vortex. , flows between adjacent field coils 6 as shown by arrow D. Also, magnetically,
The 4th section of the ventilation duct used to be a blank space, but
The interposition of the magnetic filler piece 20 partially increases the magnetic path cross-sectional area. Furthermore, from the magnetic pole core 6 to the spider rim 1
The magnetic flux that enters the adjacent magnetic pole core 6 is the fourth
As shown by the dotted arrow in the figure, in the ventilation duct 4 section, the magnetic filling piece 20 passes through the contact surface between the bottom surface and the top surface 20a of the field core 6, and the contact surface between the dovetail keys 9 on both sides and both side surfaces 20b. . The magnetic flux passing through the magnetic filling piece 20 enters the spider rim 1 from both end surfaces 20c through the contact surface with the end surface of the spider rim 1 at the ventilation duct 4 section. In this way, the contact area of the magnetic path between the magnetic pole core 6 and the spider rim 1 is increased by the magnetic filling piece 20 of the ventilation duct 4,
The magnetic resistance decreases accordingly, and the magnetic flux value increases.

The material of the magnetic filling piece 20 may be a steel piece having the same magnetic permeability as the spider rim 1, or a silicon steel plate having a higher magnetic permeability laminated to form an integral filling piece.

The adhesion of the magnetic filling piece 20 to the spider rim 1 is as follows:
It is generally fixed by a bolt (not shown), but since the attachment point is sandwiched between a pair of dovetails 7 and the outer diameter side contacts the bottom surface of the magnetic pole core 6, a pin (not shown) is used. It can be easily fixed by using a combination of bolts and pins, or by various other means.

The shape of the magnetic filler piece 20 is such that the outer diameter side contacts the bottom surface of the magnetic pole core 6, and both side surfaces contact both dovetail keys 9, filling the space between the dovetails 7 and reducing magnetic resistance.

As described above, according to the present invention, since a magnetic filler piece is attached between a pair of dovetails in the ventilation duct part of the spider rim, the magnetic path cross-sectional area of that part increases, and the magnetic pole core and the spider rim side The contact area of the magnetic path with the magnet is increased, the magnetic flux value is increased, and the external length is reduced compared to the past, reducing the price. Also, the ventilation resistance of the dovetail part of the magnetic pole core in the ventilation duct part of the spider rim is reduced. be done.

[Brief explanation of the drawing]

FIG. 1 is a plan sectional view of essential parts of a conventional salient pole rotor, FIG. 2 is a sectional view taken along the line - in FIG. 1, and FIG. 3 is a salient pole rotor according to an embodiment of the present invention. FIG. 4 is a cross-sectional view taken along the line ``--'' in FIG. 3, and FIG. 5 is a perspective view of the magnetic filling piece shown in FIG. 3. 1... Spider rim, 4... Ventilation duct, 5...
...Dovetail slot, 6...Magnetic pole core, 7...
Dovetail, 20...magnetic filling piece. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] 1. A spider rim provided with a radial ventilation duct, a pair of dovetail slots provided at each magnetic pole mounting position on the outer periphery, and a pair of dovetails protruding from the bottom. The magnetic pole core is fitted into the pair of dovetail slots of the spider rim and fixedly supported by dovetail keys driven into both sides of each dovetail, and the magnetic pole core is fixedly inserted between the pair of dovetails of the ventilation duct part of the spider rim. The cross-sectional area of the magnetic path and the contact area are A salient pole rotor characterized in that it is equipped with magnetic filler pieces that increase the . 2. The salient pole rotor according to claim 1, wherein the magnetic filling pieces are formed by laminating iron core plates with high magnetic permeability.