JPH1023692A - Rotor for electric rotary machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce local overheating in a stator core-end structure by placing a magnetic structure between the outside surface of the end of a field winding and the inside surface of a retaining ring, and thereby letting part of magnetic flux, produced at the end of the field winding, through the magnetic structure having a low magnetic resistance to reduce magnetic flux entering the end of a stator core. SOLUTION: A conductive sheet plate 8 is placed on the surface of the end plate 3 at the end of a stator core 1. The end of the stator core 1 is cut stepwise on its inside, and a magnetic structure 10 is placed between the outside surface of the end 6b of a rotor 5 field winding and the inside surface of a retaining ring 7. Thus part of magnetic flux ϕ produced from the field winding 6 is let through the magnetic structure 10, having a low magnetic resistance. This reduces the magnetic flux ϕ entering the end of the stator core 1 and enables the reduction of local overheating in the structure at the end of the stator core 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotor of a rotary electric machine, and more particularly to a cylindrical rotor of a turbine generator for reducing local overheating of a stator core end structure.

[0002]

2. Description of the Related Art FIG. 2 shows a partial cross-sectional structure at an axial end of a conventional rotating electric machine having a cylindrical field pole. The stator core 1 is formed by laminating thin iron plates, and is fixed by tightening bolts (not shown) via end ducts 2 and end plates 3. Slots (not shown) are provided in the stator core 1 and armature windings 4 are inserted therein. On the other hand, the rotor 5 is installed on the inner diameter side of the stator core 1 with a gap. The rotor 5 is also provided with a slot (not shown), into which the field winding 6 is inserted. The field winding 6 comprises a field winding linear portion 6a and a field winding end 6b, and is held and fixed by a holding ring 7 made of non-magnetic steel. The retaining ring 7 is formed in a smooth cylindrical shape, and is shrink-fitted to the rotor 5.

A stator core end structure composed of an end plate 3 and an end of the stator core 1 has a stator core end structure formed by a magnetomotive force of a field winding end 6b and a magnetomotive force of an armature winding 4. Since it is asynchronous with the magnetic flux φ incident on the part, an eddy current flows and causes a temperature rise due to local overheating. Therefore, a conductive shield plate 8 for shielding the magnetic flux φ is provided on the surface of the end plate 3 to reduce the eddy current generated in the end plate 3. A step 9 is provided on the inner diameter side of the end of the stator core 1 to reduce the incidence of the magnetic flux φ.
In addition, Japanese Utility Model Publication No. 3-29973 can be cited as a rotating electric machine winding.

[0004]

In the prior art, a step is provided at the end of the stator core or a shield plate 8 is provided on the surface of the end plate to reduce the incidence of magnetic flux and reduce the eddy current. However, despite these measures, the temperature rise of the stator core end structure is much greater than in other parts. For this reason, increasing the capacity or reducing the size of the rotating electric machine is restricted by the temperature of the stator core end structure, which is a major problem.

[0005]

According to the present invention, a structure (hereinafter, referred to as a magnetic structure) made of a magnetic material is provided between an outer periphery of a field winding end and an inner periphery of a retaining ring. The purpose of this is to achieve.

By providing a magnetic structure between the outer periphery of the end of the field winding and the inner periphery of the retaining ring, part of the magnetic flux generated from the end of the field winding is converted to a magnetic structure having a low magnetic resistance. Flows. For this reason, the magnetic flux which enters into the end of the stator core is reduced, and the rotor of the rotating electric machine which can reduce local overheating of the end structure of the stator core is obtained.

[0007]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a partial sectional view of an axial end portion of a rotating electric machine according to an embodiment of the present invention. Here, the present invention will be described by taking a case of a two-pole machine as an example, but the following invention generally holds for even-pole machines having two or more poles.

In the present invention, as shown in FIG.
The magnetic structure 10 was provided between the outer periphery of the holding ring 7 and the inner periphery of the holding ring 7. In FIG. 1, the magnetic structure 10 is formed into a cylindrical shape,
Attached to.

In this way, a part of the magnetic flux generated from the field winding is reduced to the magnetic structure 10 having a small magnetic resistance.
To flow to. Therefore, the magnetic flux φ incident on the end of the stator core is reduced as compared with the related art, so that it is possible to obtain a rotor of a rotating electrical machine that can reduce local overheating of the end structure of the stator core.

Since the magnetic structure 10 is mounted on the holding ring 7, it rotates synchronously with the rotating magnetic field. Therefore, the magnetic field incident on the magnetic structure 10 is mainly a DC magnetic field, and the loss due to the eddy current of the magnetic structure 10 is small. Since a large centrifugal force is applied to the rotor 5, the magnetic structure 10 is provided on the inner peripheral side of the holding ring 7, so that the magnetic structure 10 is easily fixed.

The magnetic structure 10 may be made of any material having a lower magnetic resistance than air. FIG. 3 shows another embodiment of the present invention. FIG. 3 shows a sectional view of the rotor 5 in the circumferential direction.
In the embodiment shown in FIG. 1, the magnetic structure 10 is provided over the entire circumference of the rotor 5. In this embodiment, the magnetic structure 10 is provided only on the magnetic pole portion 11.

The magnetic flux φ incident on the end of the stator core flows mainly from the magnetic pole portion 11. Therefore, even if the magnetic structure 10 is provided only on the magnetic pole part 11, the magnetic flux φ incident on the end of the stator core
Can be reduced. By doing this,
The magnetic structure 10 can achieve an effect that the weight can be reduced as compared with the embodiment of FIG. 1 and the local overheating of the stator core end structure can be reduced.

FIG. 4 shows another embodiment of the present invention. FIG. 4 shows a sectional view of the rotor 5 in the circumferential direction. In this embodiment, the volume of the magnetic structure 10 in the embodiment of FIG.

When a load is applied to the rotating electric machine, the magnetic flux
It concentrates on the rotation direction delay side close to 1. Accordingly, by increasing the volume of the magnetic structure 10 on the delay side in the rotation direction where the magnetic flux concentrates at the center of the magnetic pole portion 11, the magnetic flux φ incident on the end of the stator core at the time of load decreases. By doing so, the magnetic structure 10 can be made lighter than the embodiment of FIG. 3 and the effect of reducing local overheating of the stator core end structure can be obtained.

FIG. 5 shows another embodiment of the present invention. FIG. 5 shows a circumferential cross-sectional structure of the magnetic structure 10. In this embodiment, the magnetic structure 10 is formed by forming a narrow groove 12 parallel to the axial direction of the rotor 5 on the outer peripheral surface thereof. This is a magnetic structure 1
A value of 0 addresses the case where the eddy current due to the slot ripple of the armature winding 4 flows and the efficiency of the generator is reduced not only at the time of unbalanced load such as at the time of an accident but also at the time of steady operation. By providing the narrow groove 12 on the outer peripheral surface of the magnetic structure 10,
The equivalent eddy current flow path becomes longer and eddy current can be reduced. The same effect can be obtained even if the shape of the narrow groove 12 is corrugated or triangular. In the present embodiment, the narrow groove 12 is used.
Is provided in parallel with the axial direction of the rotor 5, but the same effect can be obtained by providing the right angle with the axial direction of the rotor 5 or at an angle with the axial direction of the rotor 5. .

FIG. 6 shows another embodiment of the present invention. FIG. 6 is a sectional view in the circumferential direction of the rotor 5. In this embodiment, the magnetic structure 10 is divided and arranged in parallel with the axial direction of the rotor 5. The magnetic flux generated from the end of the field winding mainly includes an axial component and a radial component of the rotor 5. Therefore, if the magnetic structure 10 is continuous without being divided in the axial direction of the rotor 5, the intended purpose can be achieved. By arranging the magnetic structure 10 in such a manner as to be divided in parallel to the axial direction of the rotor 5, the weight of the magnetic structure 10 is reduced, and the magnetic flux φ incident on the end of the stator core is reduced. Can
Local overheating of the stator core end structure can be reduced.

In this embodiment, the magnetic structure 10 is provided over the entire circumference of the rotor 5. However, the magnetic structure 10 is provided only on the magnetic pole portion 11 or in the same manner as in the embodiment of FIGS. The same effect can be obtained by increasing the volume of the magnetic structure 10 on the lag side relative to the leading side in the rotation direction with respect to the center of the portion 11.

[0019]

According to the rotor of the rotary electric machine of the present invention, since the magnetic structure is provided between the outer periphery of the end portion of the field winding and the inner periphery of the holding ring, the end portion of the field winding is provided. Part of the magnetic flux generated from the portion flows to the magnetic structure having a small magnetic resistance. For this reason, the magnetic flux incident on the stator core end can be reduced as compared with the prior art, and a rotor of a rotating electrical machine that can reduce local overheating of the stator core end structure can be obtained.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of an end in an axial direction of a rotating electric machine according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view of an axial end of a conventional rotary electric machine.

FIG. 3 is a sectional view of a rotary electric machine in a circumferential direction of a rotary electric machine according to another embodiment of the present invention.

FIG. 4 is a sectional view of a rotary electric machine in a circumferential direction of a rotary electric machine showing another embodiment of the present invention.

FIG. 5 is a circumferential partial sectional view of a magnetic structure showing another embodiment of the present invention.

FIG. 6 is a sectional view of a rotating electric machine in a circumferential direction of a rotating electric machine according to another embodiment of the present invention.

[Explanation of symbols]

5 rotor, 6 field winding, 6a field winding linear section, 6
b: field winding end, 7: retaining ring, 10: magnetic structure, 1
1 ... magnetic pole part, 12 ... narrow groove.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Mika Takahashi 7-2-1, Omika-cho, Hitachi City, Ibaraki Pref. Power and Electricity Development Division, Hitachi, Ltd. Hitachi 1-1, Yokocho 3-1-1, Hitachi, Ltd.Hitachi Plant (72) Inventor Ryoichi Shiohara 3-1-1, Yachimachi, Hitachi-City, Ibaraki Pref.

Claims (5)

[Claims] 1. A rotor of a rotating electrical machine having a field winding comprising a magnetic pole portion, a field winding linear portion, and a field winding end, and a retaining ring made of non-magnetic steel. A rotor for a rotating electric machine, wherein a magnetic structure is provided between an outer periphery of an end portion and an inner periphery of the holding ring. 2. The rotating electric machine according to claim 1, wherein said magnetic structure is attached only to said magnetic pole portion. 3. The rotor of a rotating electric machine according to claim 1, wherein the volume of the magnetic structure is larger on the delay side in the rotation direction than the center of the magnetic pole portion. 4. The rotor of a rotating electric machine according to claim 1, wherein a narrow groove is provided on an outer periphery of said magnetic structure. 5. The rotor of a rotating electric machine according to claim 1, wherein said magnetic structure is divided in parallel to the axial direction of said rotor.