JPS6137854B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a rotating electrical machine, and particularly to an improvement in a rotating electrical machine having a stator core formed by laminating thin iron plates.

Generally, rotating electric machines are equipped with a stator core, an armature winding, and a field winding on the rotor side.The stator core is formed by laminating thin iron plates, and these are attached to a stator core holding plate. It is tightened and fixed to the stator frame with tightening bolts. By the way, near the axial ends of this stator core, leakage magnetic flux increases as the field winding magnetomotive force and armature winding magnetomotive force increase due to the increase in capacity of rotating electric machines, etc. causing a rise in temperature. These localized heatings are a major factor that hinders increasing the capacity of machines. Therefore, leakage magnetic flux to the stator core end is reduced,
One way to eliminate local heating is to make the stator core lamination longer than the rotor effective length to reduce the magnetic flux that enters the stator core end from the axial direction, thereby eliminating local overheating at the stator core end. method has been adopted.

Figure 1 shows a partial cross section near the end of the stator core of a rotating electric machine in which the stator core lamination length is longer than the effective length of the field magnetic poles, as described above, using a cylindrical field type rotating electric machine as an example. This is what is shown.

The stator core 1 is formed by stacking a plurality of laminated blocks made of thin iron plates laminated to a predetermined thickness via ventilation ducts, and is secured by tightening bolts (not shown) through an end duct 2 and a core holding plate 3. It is tightened and fixed. This stator core 1 has an annular shape as a whole, and a slot is provided in the inner surface of the stator core 1, into which an armature winding 4 is inserted. A conductive shield plate 5 is provided around the core holding plate 3 to shield leakage magnetic flux. On the other hand, rotor 6
are installed on the inner diameter side of the annular stator core 1 with a gap in between. The rotor 6 is also provided with a slot, into which the field winding 7 is inserted. A damper winding 8 is inserted above this field winding 7, and the straight part 7a of this damper winding and the field winding is held by a wedge 9, and the end part 7b of the field winding is held by a wedge 9.
is held fixed by a pro-ring 10, which is generally made of non-magnetic steel. Proring 10 is
It is formed into a cylindrical shape and is shrink-fitted into a recess at the axial end of the rotor 6.

By the way, FIG. 2 is an enlarged perspective view of section A in FIG. , leakage magnetic flux, etc. exist in a complicated manner. This leakage magnetic flux exerts a complex electromagnetic force on the axial ends of the armature winding (not shown), which is different from that on the axial center. On the other hand, even in the method of making the stator core lamination length longer than the rotor effective length, it is impossible to completely eliminate the axial magnetic flux incident on the end of the core, resulting in the occurrence of eddy current loss caused by leakage magnetic flux, or , magnetic flux concentration at the corners of the stator core occurs. In order to avoid this, generally a step 11 or a radial slit 12 or the like is provided in the iron core.
For this reason, the iron core in this part is mechanically very weak. To solve these problems, an adhesive or the like is applied to the surface of the thin iron plate, and the adhesive is cured to maintain mechanical strength. However, as mentioned above, although the thin iron plate provided with the slits is tightened through the end duct 2 at the end of the stator core, due to its structure, pressure is applied over the entire surface of the core teeth 13. (particularly helped by the fact that the core has a large stacked thickness), and because the iron plate constituting the core is thin, curling occurs near the tip 13a of the core tooth portion, resulting in a significant decrease in bonding strength, and furthermore, the core tooth portion This induces electromagnetic vibration, which causes cracks to occur due to repeated fatigue in the slitted core teeth, etc.
Alternatively, various problems such as significantly accelerating the deterioration of the insulating layer of adjacent armature windings occur, which disturb the normal operation of the rotating electric machine, and significantly reduce reliability.

An object of the present invention is to provide a highly reliable rotating electrical machine by increasing the strength of the teeth at the end of the stator core even in this type of rotating electrical machine.

In other words, the present invention eliminates the entire thickness of the thin iron plate forming the end of the stator core, especially the thin iron plate of the laminated block that protrudes in the axial direction from the rotor magnetic pole part, by removing the entire thickness of the thin iron plate of the laminated block forming the stator core end. It is made thicker than the thickness to achieve the intended purpose.

FIG. 3 shows an embodiment of the invention. The stator cores are laminated with core length L _c and rotor effective length L _f
is shorter than the stator core lamination length. The stator core central portion 1a corresponding to the rotor effective length L _f is laminated using thin iron plates, and the core end portion 1b portion that protrudes from the rotor effective length L _f is thicker than the core central portion 1a. Laminated using thin iron plates. Generally, the loss occurring at the core end 1b is
Although it is affected by the length L _d of the stator core protruding from the rotor effective length L _f , the gap length g, etc., in the embodiment shown in FIG. 3, the unit volume generated at the core end 1b is The length L _d of the protrusion and the thickness of the thin iron plate are adjusted so that the loss per unit volume that occurs in the central portion 1a of the core within the length L _d of the protrusion is approximately the same. The thickness of the thin iron plate forming the core end portion 1b is two to three times that of the thin iron plate forming the core central portion 1a.

For this reason, even if a slit or a step is provided at the end of the core, the mechanical strength will not be significantly reduced. This makes it possible to increase the strength of the core end without hindering the original purpose of preventing local overheating at the core end by making the rotor effective length shorter than the stator core length. It is possible to prevent the occurrence of cracks due to repeated fatigue in the teeth, etc., or the acceleration of deterioration of the insulating layer of the adjacent armature winding, and the reliability of the rotating electric machine can be significantly improved.

FIG. 4 shows another embodiment of the invention. The embodiment shown in FIG. 3 is one in which the thickness of the thin iron plate is changed for the core portion that protrudes from the rotor effective area L _f regardless of the laminated block width W, but the embodiment shown in FIG. This shows the case where the thickness of the thin iron plate is changed over the width W of the laminated block corresponding to the effective long end of the rotor.

In FIG. 5, the thickness of the thin iron plate 1c is increased at the slit and stepped portions where the strength is the weakest.

Fig. 6 shows the laminated blocks 1d, 1e, 1 in which the thickness of the thin iron plates protruding from the effective length of the rotor is sequentially increased.
The stator core end portion is formed by increasing the thickness in the order of f and 1g.

As shown in FIGS. 4, 5, and 6, in the laminated block at the end of the core, the thickness of the thin iron plate is made thicker than that of the thin iron plate forming the central part of the stator core. It is possible to significantly increase the strength of the core end without causing extreme loss concentration.

As described above, according to the present invention, the thickness of the thin iron plate of the laminated block protruding in the axial direction from the rotor magnetic pole portion is made thicker than that of the other laminated blocks. The strength can be significantly increased, and the reliability of the rotating electric machine can be significantly increased.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a conventional stator core end, taking a turbine generator as an example, Fig. 2 is an enlarged perspective view of section A in Fig. 1, Figs. 3, 4, and 5. , FIG. 6 is a sectional view of a main part showing an embodiment of the present invention. 1... Stator core, 2... End duct, 6...
... rotor, 11 ... paragraph, 12 ... slit,
13... Iron core tooth part.

Claims (1)

[Scope of Claims] 1. A laminated stator core having an annular shape and a rotor rotatably disposed within the annular shape of the laminated stator core, wherein the laminated stator core rotates a thin iron plate to a predetermined thickness. A rotor is formed by stacking a plurality of laminated blocks and having ventilation ducts between the laminated blocks, and the length in the axial direction of the magnetic pole portion of the rotor is formed to be short with respect to the total thickness of the laminated blocks. In a rotating electric machine, the total thickness of the thin iron plates of the laminated block that protrude in the axial direction from the rotor magnetic pole part is
A rotating electric machine characterized by having a thickness greater than that of other laminated blocks. 2. The rotating electric machine according to claim 1, wherein the thickness of the thin iron plate of the laminated block protruding in the axial direction from the rotor magnetic pole portion is increased toward the axial end of each laminated block. .