JP2014121166A - Rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that, in a rotary electric machine, a holding ring made of nonmagnetic steel is fixed to an end part of a rotor winding protruding from an end of a rotor iron core, and because the rotor winding at the end part or a spacer member in the winding is not always evenly distributed in a circumferential direction, the distribution causes oval deformation of the holding ring to generate bending stress, resulting in increased a load on the holding ring.SOLUTION: The rotary electric machine includes a rotor iron core in which a plurality of slots in an axial direction are formed in the circumferential direction, a rotor winding which is attached inside the slot of the rotor iron core, the holding ring which is attached to both end parts in a length direction of the rotor iron core and holds the end part of the rotor winding protruding from the end of the rotor iron core against centrifugal force, and a holding ring support fixed to the holding ring. In the rotary electric machine, rigidity on a pole core side of the holding ring support and rigidity on inter-pole side are different from each other.

Description

The present invention relates to a rotary electric machine such as a steam turbine generator or a gas turbine generator, and more particularly to a rotary electric machine having a structure in which an end of a rotor winding protruding from a rotor core is held by a holding ring.

  In general, since a rotating machine rotates at a high speed, a large centrifugal force acts on an end portion of a rotor winding projecting in the axial direction of a stator core. Therefore, the outer periphery of the rotor winding end is held by a high-strength steel holding ring attached to the axial end of the rotor core by shrink fitting so that the centrifugal winding force does not deform the rotor winding end.

  The rotor rotates at a high speed and generates a huge centrifugal force. The capacity of generators is increasing, and this is realized by increasing the rotor diameter, etc., but this leads to an increase in centrifugal force, and ensuring the reliability of the retaining ring limits the generator capacity. It is coming.

  The rotor winding end is balanced to be symmetric about the central axis so that the rotation is stable, but it is not uniform in the circumferential direction, so the circumferential weight distribution of the rotor winding end Accordingly, the magnitude of the centrifugal force acting according to the distribution is also distributed, so that the retaining ring does not remain circular but deforms into an elliptical shape.

  The retaining ring is the part where the maximum load is originally generated in the structure of the generator. Further, when bending stress occurs due to such elliptical deformation and the load increases, the required material strength increases, and the material that satisfies it is obtained. Becomes difficult. Therefore, it is necessary to reduce the load applied to the retaining ring by reducing such elliptical deformation.

  As background art of this technical field, there is JP-A-58-116036 (Patent Document 1). This publication states that “the tightening allowance of the portion that is shrink-fitted between the poles of the holding ring is smaller than the tightening allowance of the portion that is shrink-fit to the magnetic pole”.

  By adopting such a structure, it is possible to suppress elliptical deformation due to nonuniform rigidity of the rotor core 2 on the iron core side.

  There is also JP-A-58-66549 (Patent Document 2). This publication states that “the end bell portion is formed by an end bell and an end ring, and the fitting margin between the end bell and the end ring is set so that a high surface pressure is generated only in the vicinity of the position where the maximum shear stress is generated. It is characterized by a change in direction. "

By adopting such a structure, the frictional resistance is controlled, and the elliptical deformation can be suppressed by reducing the slip.

JP 58-116036 A JP 58-66549 A

  As the capacity of the generator is increased, the load generated on the retaining ring is increasing. For this reason, it is necessary to reduce the elliptical deformation caused by the uneven distribution of the weight of the coil end in the circumferential direction and to suppress the bending stress.

  Patent Document 1 shows a structure that suppresses elliptic deformation on the iron core side, but the other end of the holding ring support side is less rigid and more easily deformed, but there is no description for this.

  In Patent Document 2, it is possible to reduce the slip on the end ring (holding ring support) side and suppress elliptical deformation, but there is a possibility that the maximum angle of the shear stress varies depending on the distribution of the coil weight. Since it is necessary to grasp the position and to match the position in the circumferential direction with high precision, it is difficult to assemble and may increase the cost.

  In order to solve the above problems, for example, the configuration described in the claims is adopted.

The present application includes a plurality of means for solving the above-described problems. To give an example, “a rotor core provided with magnetic poles and poles, and a plurality of slots provided in the circumferential direction between the poles of the iron core; A rotor winding mounted in the slot, a holding ring mounted at both ends in the longitudinal direction of the rotor core and holding ends of the rotor winding protruding from the rotor core from centrifugal force, and the holding ring In the rotating electrical machine including the holding ring support that is fixed to the holding ring support, the rigidity on the pole core side and the rigidity on the pole side of the holding ring support are different.

By implementing the present invention, the elliptical deformation of the retaining ring can be reduced and the bending stress caused thereby can be reduced, so that the reliability of the retaining ring can be improved and the specification of the material can be lowered. Cost can also be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side sectional view showing an overall configuration of a rotating electrical machine that is a first embodiment of the present invention. It is the figure seen from the coil end part side of the conventional rotary electric machine. It is sectional drawing of the iron core edge part of the conventional rotary electric machine. FIG. 5 is a view of a rotating electrical machine as a second embodiment of the present invention as viewed from the coil end side. It is sectional drawing of the fitting part of the coil end part of this invention. It is sectional drawing of the fitting part of the coil end part at the time of shrink fitting of this invention. It is sectional drawing of the fitting part of the coil end part at the time of rotation of this invention. It is a characteristic view showing the relationship between the amount of elliptical deformation and the circumferential stress in the retaining ring of the present invention. It is a deformation | transformation state comparison explanatory drawing in the past and this invention. It is the sectional side view shown as a whole structure of the rotary electric machine which is another one Example of this invention. FIG. 5 is a cross-sectional view of a coil end portion of a rotating electrical machine that is a second embodiment of the present invention. FIG. 6 is a cross-sectional view of a coil end portion of a rotating electrical machine that is a third embodiment of the present invention.

  Hereinafter, examples will be described with reference to the drawings.

  In this embodiment, an example of a rotating electrical machine in which the thickness of a cylindrical holding ring support is changed will be described.

  FIG. 1 is an example of a configuration diagram of a rotating electrical machine according to the present embodiment. The rotor is composed of a rotor core 2 composed of a massive iron core and coils 3 inserted into a plurality of slots provided in the circumferential direction of the rotor core. The rotor core is integrally provided on the rotary shaft 1 by being cast integrally with the rotary shaft 1 or fixed via a fixture. Both ends of the coil 3 are structured to overhang from the iron core, and are supported by the retaining ring 5 to prevent scattering due to centrifugal force. In addition, an annular holding ring support 4 is arranged at the end of the holding ring to suppress deformation in the radial direction. The holding ring is shrink-fitted to the end of the rotary vibration core, and a holding ring support is fitted to the other end of the holding ring.

  When the rotor core is a two-pole machine, as shown in FIG. 3, there are a pole part without a slot 6 to be N pole and S pole and a part between the poles, and a coil coupling part (not shown) ) And spacers (not shown) disposed between the coils, and the like, the structure is not symmetrical with respect to the central axis.

  Here, a description will be given of a case where a large amount of these weight distributions are distributed on the pole side in the range from the pole side to the pole side. In such a case, as shown in FIG. 4, the inner diameter on the pole core side of the holding ring support is increased to reduce the wall thickness, and the inner diameter on the pole side is decreased to increase the wall thickness. With such a configuration, the centrifugal force due to the holding ring support itself becomes smaller on the pole side and larger on the gap side, so that it cancels out the load due to the distribution of the coils and the like, and becomes a uniform load in the circumferential direction. On the other hand, distribution also occurs in the rigidity of the retaining ring support. However, since the centrifugal force distribution does not affect the radial deformation, the elliptical deformation of the retaining ring can be reduced as a result.

  As shown in Fig. 8, the amount of change in the inner diameter of the retaining ring corresponds to the weight distribution of the coil, etc., so it can be optimized depending on the generator configuration. However, the smaller one also reduces the distribution of the inner diameter of the holding ring support.

  Elliptical deformation is determined by the centrifugal force due to the weight of each part and the distance from the pole, but if, for example, a distribution of 10 kg occurs in terms of the weight concentrated at the pole, the holding ring support is the same weight as that between the poles. It is desirable to adjust the wall thickness so that it becomes a distribution of 10 kg in terms of.

  Further, in FIG. 4, the shape of the inner diameter is shown as an ellipse, but it is obvious that the same shape may not be necessary if a similar weight distribution can be provided.

In the above embodiment, the case where there is a large weight distribution on the pole side has been described, but conversely, when there is a large weight distribution on the gap side, the inner diameter distribution of the holding ring support should also be made smaller on the pole side. It is obvious that this can be dealt with by increasing the wall thickness, increasing the inner diameter of the gap side and decreasing the wall thickness.

  In the present embodiment, an example of a rotating electrical machine in which the shrinkage allowance of a cylindrical holding ring support is changed in the axial direction will be described.

  In this embodiment, as shown in FIG. 5, the holding ring support is a cylindrical member arranged inside the holding ring, and both are fixed by fitting. Has increased.

  The retaining ring is shrink-fitted at both ends of the iron core side and the retaining ring support side, and since these parts are supported, the state after shrink-fitting is a convex shape downward as shown in FIG. It has become. Even at the time of rotation, since the central part of both has no reinforcing structure, the deformation due to the centrifugal force at the time of rotation is large, and gradually becomes upwardly convex as shown in FIG. This deformation changes the contact state of the shrink-fitted parts at both ends of the holding ring, and a larger surface pressure is generated in the part from the center before rotation, but the end side is in contact with the center side during rotation, and it is closer to the center. The part is easy to leave. In this structure, the shrinkage allowance on the iron core side is increased, so there are fewer parts away and the surface pressure is higher than in the case where the shrinkage allowance in the axial direction is constant as in the conventional case. The frictional resistance when the ring support slides relatively is large, the amount of sliding in the circumferential direction can be reduced, and the amount of elliptical deformation is also reduced.

  In FIG. 9, the horizontal axis represents displacement / linear displacement during rated rotation, and the vertical axis represents the rotation speed / rated rotation speed, in the case of this example (thick line) and the conventional structure (thin line). ) Result. In this embodiment, the number of rotations at which sliding starts is higher, and the non-linear displacement due to sliding is smaller. Therefore, the amount of residual deformation after stopping is also reduced. Thus, by optimizing the shrink-fitting allowance, deformation that leads to an increase in bending stress can be suppressed, and the reliability of the retaining ring can be improved.

  The fitting allowance can be realized by giving a tapered distribution to the outer diameter of the retaining ring support and increasing the outer diameter on the center side. On the contrary, the same effect can be obtained by providing a tapered distribution on the inner diameter of the retaining ring. Moreover, a taper may be formed in both, the taper amount may be adjusted, and a relative fastening allowance may be adjusted.

  The inclination of the taper is appropriate in accordance with the change in the inclination of the shrink-fitted portion that occurs between rotation and stationary. For example, if the deformation amount on the iron core side of the retaining ring shrink-fit surface (inner surface) is 0.2mm larger on the iron core side when stationary and rotating than the deformation amount on the end side, it can follow this The taper is inclined so that the iron core side of the retaining ring support is 0.2mm higher. By doing so, an appropriate contact state can be maintained during rotation, and the amount of elliptical deformation can be reduced. As described above, it is desirable to make the taper amount equivalent to the difference between the iron core side and the end side when the holding ring is stationary and rotated, but it is obvious that a certain effect can be obtained even below that.

  The shape of the retaining ring and retaining ring support, and its combination of shrink-fitting allowances, are not uniquely determined, but the effect of increasing the contact surface pressure when taper is added compared to when the shrink-fitting allowance is increased uniformly. When the taper is large, for example, 0.1 mm, an increase of several times is seen compared to the amount of increase when uniformly increasing 0.1 mm or more.

  As described above, when the taper shape is used, since the shrinkage allowance of the retaining ring support can be made smaller than when the shrinkage fit is uniformly increased, the temperature increase required at the time of shrinkage fitting can be suppressed. Since an unnecessary load due to temperature rise is not applied and the assembly process can be shortened, a low-cost and highly reliable structure can be realized.

  If this embodiment is used in combination with the structure shown in Embodiment 1, an effect of suppressing elliptic deformation can be expected.

  FIG. 10 is an example of a configuration diagram of the rotating electrical machine of the present embodiment. In FIG. 10, the description of the components having the same functions as those already described with reference to FIG. 1 is omitted.

  In this embodiment, as shown in FIG. 11, a columnar member is disposed between the holding ring 5 and the rotary shaft 1 as the holding ring support 4a. These are each fixed by welding or the like. Here, a case where the deformation on the extreme core side is large in a two-pole machine is shown. In this case, it arrange | positions so that it may become a pair in the position symmetrical with respect to the center axis | shaft of the pole center side.

  Thus, the deformation | transformation of a holding | maintenance ring is made small by couple | bonding the polar axis side and rotating shaft of a holding | maintenance ring to which a deformation | transformation becomes large with a rigid body. When such a holding ring support is used, the volume is smaller than when a cylindrical holding ring support is used. Therefore, the material cost of the holding ring support can be reduced. Moreover, since the shape is simple, the processing cost of the member is reduced. Further, since the cylindrical holding ring support needs to be shrink-fitted to the holding ring, this assembling process is eliminated.

  FIG. 12 is a configuration diagram in a case where the holding ring support 4b on the inter-pole side is arranged in addition to the holding ring support 4a on the pole side. In this case, although the number of members increases, the radial deformation of the retaining ring can be reduced as a whole, and the degree of elliptical deformation is also reduced, so that the load on the retaining ring can be further reduced. Also in this case, they are arranged in pairs at positions that are symmetrical with respect to the central axis. For example, as shown in the figure, if four locations are arranged every 90 degrees from the pole, the distribution due to the retaining ring support can be minimized.

In such a case, the rigidity of each holding ring support is changed in accordance with the radial displacement generated in the holding ring during rotation between the pole side and the pole side. For example, if the ratio of the deformation that occurs on the pole side and the deformation that occurs on the gap side is 0.9, if the rigidity of the holding ring support on the pole side is 0.9 times that of the holding ring support on the pole side, The difference in deformation amount can be reduced, and the elliptical deformation amount can be reduced. In this way, it is desirable to match the rigidity of the retaining ring support to the deformation amount on the pole side and the pole side, but if a difference in the direction in which the two are brought closer is given, a certain effect can be obtained even with a difference in stiffness of less than It is self-explanatory.

DESCRIPTION OF SYMBOLS 1 ... Rotary shaft, 2 ... Rotor iron core, 3 ... Coil, 4 ... Holding ring support, 5 ... Holding ring, 6 ... Slot, 10 ... Polar core, 11 ... Between poles

Claims (4)

A rotor core provided with magnetic poles and poles, a plurality of slots provided in the circumferential direction between the poles of the iron core, a rotor winding mounted in the slot, and attached to both longitudinal ends of the rotor core In a rotary electric machine comprising a holding ring that holds the end of the rotor winding protruding from the rotor core from centrifugal force, and a holding ring support that is fixed to the holding ring, on the pole side of the holding ring support A rotating electric machine characterized in that the rigidity and the rigidity on the inter-electrode side are different.
2. The rotating electrical machine according to claim 1, wherein the holding ring support is a cylindrical member disposed inside the holding ring, and the thickness on the pole side is smaller than the thickness on the gap side. Electric.
2. The rotating electrical machine according to claim 1, wherein the holding ring support is a cylindrical member disposed inside the holding ring, and both the holding ring support and the holding ring are fixed by fitting. A rotating electrical machine characterized in that the tightening margin of the part is larger on the iron core side.

The rotating electrical machine according to claim 1, wherein the holding ring support is a columnar member disposed inside the holding ring, and at least one pair or more in a symmetrical position with respect to the central axis, between the rotor core and the holding ring. A rotating electrical machine that is arranged and restrains deformation between the two.