JPH0140295Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of a field core in a rotating electrical machine such as an alternating current generator.

In general, the most widely used type of alternating current generator is a synchronous generator in which the armature is the stator and the field iron pole is the rotor.The rotating field iron core of this synchronous generator is shown in Figure 1. It has a salient pole shape as shown in Figure 2, and is made by punching thin steel sheets such as silicon steel plates into the shape shown in Figure 2 by press working, laminating them to a predetermined thickness and joining them together with multiple rivets. The dovetail-shaped protrusion 1a of the fixed magnetic pole piece 1 is fitted and fixed into the dovetail-shaped groove 4 formed at a predetermined interval on the outer periphery of a beam 3 as shown in FIG. 3 which is integral with the rotating shaft 2. A rotating field core as shown in Fig. 1 is manufactured, but in the conventional rotating field core configured in this way, each magnetic pole piece 1 and the comparison winding around each magnetic pole piece 1 are A considerable amount of effort was required to manufacture the radial iron 3 that can withstand the strong centrifugal force caused by the heavy field coil (not shown) and that also supports the pitches between the poles of each magnetic pole piece 1 at exactly equal intervals. Not only is it time consuming and expensive, but the means for supporting the coil (not shown) wound around the magnetic pole piece 1 is also relatively troublesome, and furthermore, the circulation of cooling air into this coil is poor. The disadvantage is that the coil temperature tends to rise.

As a means to deal with this drawback, as shown in FIG. 5, a thin steel plate material such as a silicon steel plate is pressed into a shape as shown in FIG. 5, that is, a rotating shaft 2 is inserted in the center thereof. A central hole 5 for cooling, a ventilation passage 6 for circulating cooling air outside the central hole 5, a large number of slots 7 for winding coils (not shown) on the outer periphery, and a predetermined number of slots 7 without slots 7. The main poles 8 are punched out and formed into one piece, and then laminated to a predetermined thickness, as shown in FIG. A type that is fixed to form the rotating field iron core 12 is used.

A concentric single-layer field coil 30 as shown in FIG. 13 is inserted into the slot of the iron core 12. This inserted state is schematically shown in FIG. 16. In this case, the width L of the coil 30 is actually L1 on the inner side (lower part) of the coil and L2 on the outer side (upper side), and L2>L1. , 7, the insertion work is troublesome because it has to be expanded to the widths L1 and L2 on the inner circumferential side.Also, when the insulating material contains mica, etc. There was a risk of damage.

FIG. 7 shows a specific example of the above-mentioned rotating field core 12, in which the width of each of the four main poles 8 in the circumferential direction skips four slots 7, and the width between each main pole 8 is has six slots 7, and three concentric field coils (single-layer winding coils) (not shown) are wound around each main pole 8, and the polarity of each main pole 8 is The slots 7 and the pitches P of the skipped slots 7 in each main pole 8 are all constant. The cylindrical shape is easier to manufacture than the conventional salient pole type described above, and the means for cooling the coil and attaching the coil to the iron core are almost the same as those for a wound induction machine rotor or a DC machine armature. However, although both wound induction machines and DC machines often use double-layer diamond coils, cylindrical synchronous machines use concentrically wound single-layer coils wound around the main pole. The binding structure of is handled by a similar method. Since direct current is used as the exciting current for this cylindrical synchronous machine, the rotating field core 12 does not necessarily need to be laminated.

This invention was made with attention to this point, and is intended to provide a field core for a rotating electric machine that is easy to work, has high productivity, and has excellent electrical durability.

That is, FIG. 8 is a perspective view showing an embodiment of this invention, in which 13 is a rotating field core made of a thick steel plate with a thickness t of 5 to 100 m/m, and a slot 14 on the outer periphery is connected to the rotary field core 13. , each main pole 15 is made by copying 5 to 10 stacked thick steel plates and simultaneously cutting them into the same shape as the paper pattern using high energy density cutting means such as gas cutting, plasma cutting, or laser cutting. The center hole 16, ventilation passage 17, and keyway 18 are similarly cut out using a copying gas cutter. However, it goes without saying that the inner periphery of the center hole 16, the keyway 18, and the outer periphery of the iron core 13 are finished with high precision by machining.

The plurality of rotating field cores 13 cut into predetermined shapes as described above are as shown in FIG.
A ventilation duct 20 is formed between each iron core 13 while being inserted into the rotating shaft 19, and the gap dimensions of each ventilation duct 20 are set in accordance with the temperature rise due to the Joule heat of the armature and field coil. It is constructed so that it can be adjusted appropriately to provide warm air. Further, the thickness t of each of the rotating field cores 13 is not all the same, but can be appropriately selected depending on the ventilation, the amount of heat generated, and the amount of magnetic flux passing through.

After a plurality of field cores 13 are fitted and fixed to the rotating shaft 19 at intervals so as to form a ventilation duct 20 in this manner, the field cores 13 are inserted into the slots of the field cores 13 as shown in FIG. field coil 30
Insert. In this way, the rotor shown in FIG. 14 is formed.

In this case, as shown in FIG. 9, the thickness t of the core 13 or the interval between the ventilation ducts 20 can be changed as necessary, so the amount of ventilation can be freely selected. The temperature at the center can be lowered to the same level as at the axial ends, and the coil and core can be cooled more effectively.

As mentioned above, this idea uses a relatively thick steel plate for the rotating field core, and it is possible to simultaneously cut out a predetermined shape by stacking multiple thick steel plates and using a gas cutter, which makes machining easier. Not only is it possible to provide a field core for rotating electric machines that is simple and has extremely high productivity such as shortening the construction period, and has excellent electrical and magnetic properties, but also provides a Since ventilation ducts are formed, the gap dimensions of each ventilation duct can be adjusted as appropriate to accommodate the temperature rise due to the Joule heat of the armature and field coil. . In addition, the field core of this invention has a different shape of the main pole 15 and the slot 14, compared to the conventional one manufactured by press working from a thin steel plate material such as a silicon steel plate. There is flexibility in their arrangement, which not only facilitates design changes but also eliminates the need for special tools. Furthermore, the cutting speed of thick steel plates by the above-mentioned profiling gas cutting machine is 0.3 m to 0.5 m.
m/min, so if 5 to 10 thick steel plates are to be cut at the same time, the manufacturing speed will be significantly shortened, and since the iron core 13 is thick, the lamination work time will also be shortened. This greatly contributes to reducing the manufacturing cost of field cores. Furthermore, this idea also allows gas cutting of thick steel plates.
Alternatively, since the cutting is performed by a high energy density cutting means such as plasma cutting or laser cutting, there is no restriction on the type of steel plate, and there is also an effect that inexpensive commercially available high-strength steel plates can be used.

Note that FIGS. 10 to 12 all show other embodiments of this invention, and in FIG. 10, each slot 14 within the interval T between the main poles 15 corresponds to the number of coils to be wound. In addition to changing the size of the generator, the air gap between the main pole 15 and the slot 14 is changed to reduce the horizontal axis reactance compared to the direct axis reactance, improving the characteristics of the generator. and the size of
The purpose of adjusting the number of coils is to bring the magnetomotive force at the main pole spacing T closer to a sine wave. Also,
Since the depth of the slot 14 in the rotating field iron core in FIG. 10 is made shallow at the center between the main poles, the ventilation passage 17 can be widened at the inner diameter part of the core required as a magnetic flux passage. be. That is, by not forming the slots 14 in the same shape and size, the dimensions A and B of the magnetic flux paths can be made approximately equal. In addition,
The center line of the slot 14 is normally formed to pass through the center "O" of the iron core, but in this invention, as shown in FIG.
The slot 14 is formed substantially parallel to the center line of the main pole 15 without passing through it.

FIG. 15 schematically shows a state in which a field coil is inserted into the iron core of FIG. 10. In this example, the 17th
As shown in the figure, the field coil 31 (concentric coil as shown in FIG. 13) inserted into the slot 14 can be formed with both wire ring sides parallel to each other.
When inserting the coil into the slot, there is no need for the troublesome work of inserting both wire ring pieces with a wide gap between them as in the conventional case, and there is no risk of damage to the coil.

Next, FIG. 11 shows a case in which the field magnetomotive force is strengthened by changing the pitches P ₁ to _{P 6} of the slot 14 within the main pole spacing T.
The figure shows a further improvement to the rotating field core shown in Figure 10 above, in which each main pole 15 has a large saliency and the field coil is formed into a cylindrical shape. In addition to producing the same effects as in the embodiment, the embodiments shown in FIGS.
The outer diameter of the teeth between the four teeth is made slightly smaller. That is, since the radial gap between the stator core and the rotor is wider at the tooth portion than at the main pole portion, unnecessary reactance is reduced and the characteristics of the generator etc. are improved.

In addition, in the embodiment shown in Fig. 10, the slot dimensions are not all equal but are different, and the dimensions of the coil pieces (coil cross-sectional area) are changed, so that the magnetomotive force in the main pole spacing becomes more sinusoidal. As it gets closer, it leads to improved characteristics.

As described above, this invention has the following effects.

(a) Outer periphery, slots, and inner periphery holes can be machined quickly and efficiently using high-energy processing methods from thick plates.
The material cost is also lower than that of conventional punched iron core plates.

(b) Since the slot size and shape can be changed as needed, the characteristics can be selected as desired (conventional slots usually have one type of slot size).

(c) The direction of the slot is not radial, but can be formed parallel to the main pole (because the slot is not punched).

(d) Radial dimensions of the slot bottom and inner circumference (e.g.
Dimension H) in Fig. 15 can be freely selected because it uses a high-energy processing method, unlike punching the core plate (which requires a punching tool).
The magnetic flux density can be set arbitrarily.

(e) As mentioned in (c), since it is different from a punched iron core, the slots do not have to be arranged radially and at equal pitches, and the slot arrangement is optimal for rotating electric machines (i.e., the coil placement) becomes possible.

(f) The axial spacing of ventilation ducts can be freely selected.

(g) By changing the plate thickness, the axial dimension (thickness) of the core can be made thicker at the ends and thinner at the center. (f) and (g) make it possible to equalize the temperature rise in the rotor in the axial direction.

(h) Expensive items such as punching tools are not required, and design changes and improvements can be made at will.

[Brief explanation of the drawing]

Figures 1 to 4 all show conventional rotating field cores. Figure 1 is a front view of the rotating field core, Figure 2 is a front view of the magnetic pole piece, and Figure 3 is a front view of the rotating field core. Perspective view,
FIG. 4 is a sectional view. Figures 5 to 7 similarly show conventional rotating field cores, with Figure 5 being a front view, Figure 6 being a sectional view, and Figure 7 being a front view showing a specific example of the core in Figure 5. It is. 8 and 9 both show an embodiment of this invention, with FIG. 8 being a perspective view and FIG. 9 being a sectional view. 10 to 12 are front views showing other embodiments of this invention. Fig. 13 is a schematic diagram of a coil inserted into the conventional field core, Fig. 14 is a sectional view of the rotating field core of the present invention, and Fig. 15 is a schematic diagram of a field coil inserted into the iron core of Fig. 10. FIG. 16 is a perspective view showing the relationship between a conventional iron core and a coil, and FIG. 17 is a perspective view showing the relationship between an iron core and a coil according to an embodiment of the present invention. In the drawing, 13 is a rotating field core, 14 is a slot, 15 is a main pole, 16 is a center hole, 17 is a ventilation passage,
11 is a keyway. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A relatively thick steel plate is cut into a predetermined shape by a high energy density cutting means to form a main pole,
1. A field core for a rotating electric machine, characterized in that a plurality of field cores each having a slot, a ventilation passage, etc. are inserted into a rotating shaft, and a ventilation duct is formed between each of the field cores. (2) The field core for a rotating electric machine according to claim 1, wherein the thickness of each field core is the same or not the same. (3) The field core for a rotating electric machine according to claim 1, wherein the thick steel plate has a thickness of 5 to 100 m/m. (4) The field core for a rotating electric machine according to claim 1, which is characterized in that the high-energy density cutting means uses profiling gas cutting, plasma cutting, or laser cutting.