JP2013021811A - Rotor of rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a coolant flowing through a coolant passage in a rotor core formed by laminating magnetic steel sheets from passing through a gap formed between the magnetic steel sheets and leaking to an outer peripheral surface of the rotor.SOLUTION: A rotor core 20 is formed by laminating magnetic steel sheets. A coolant passage 30 where a coolant flows is provided in the rotor core 20. Further, a resin member 48 is formed so as to cover an outer peripheral surface of the rotor core 20. The coolant passing through a gap between the laminated magnetic steel sheets and heading to the outer peripheral surface of the rotor core is backed up by the resin member 48, and the leakage of the coolant from the outer peripheral surface of the rotor core is prevented.

Description

  The present invention relates to a rotor of a rotating electrical machine, and more particularly to a structure relating to cooling of the rotor.

  An electric motor that converts electric power into rotational motion, a generator that obtains electric power from rotational motion, and an electric device that has both functions of the electric motor and the generator are known. Hereinafter, these electric devices will be described as rotating electric machines.

  There is known a rotating electric machine in which a rotor is provided with a permanent magnet. In addition, a technique of cooling with a cooling liquid is known in order to suppress the temperature rise of the rotor. In the following Patent Document 1, a rotor of a rotating electrical machine is described in which a coolant is introduced between a rotor core formed by laminating electromagnetic steel sheets and an end plate disposed at an end of the rotor core. A preload is applied to the end plate disposed adjacent to the rotor core in the rotation axis direction in a direction toward the rotor core, and leakage of the cooling liquid from between the end plate and the rotor core when centrifugal force is applied is suppressed.

JP 2009-219186 A

  When forming the flow path of the coolant in the rotor core, there is a problem that the coolant leaks from the gap between the laminated electrical steel sheets. In Patent Document 1, an adhesive is provided between the electromagnetic steel sheets to suppress the leakage of the coolant to some extent, but this is not sufficient.

  An object of the present invention is to prevent the coolant flowing in the rotor core from leaking from the circumferential surface of the rotor core through the gaps between the laminated magnetic steel sheets constituting the rotor core.

  The rotor of the rotating electrical machine of the present invention has a rotor core formed by stacking electromagnetic steel plates. Permanent magnets are arranged along the circumference of the rotor core, and a cooling flow path through which a cooling liquid flows is formed in the rotor core. The cooling flow path is formed so that the coolant flowing through the flow path is in contact with the permanent magnet. A resin member is formed so as to cover the outer peripheral surface of the rotor core.

  The resin member can be mixed with a magnetic material. Further, the resin member may extend from the outer peripheral surface of the rotor core to the end surface of the rotor core and cover the outer peripheral portion of the end surface of the rotor core.

  By covering the outer peripheral surface of the rotor core with the resin member, the coolant is prevented from leaking to the outer peripheral surface of the rotor core through the gaps between the laminated electromagnetic steel sheets.

  By blending a magnetic material in the resin member, it is possible to suppress a decrease in magnetic characteristics caused by the resin member interposed between the rotor and the stator.

  By extending the resin member from the outer peripheral surface of the rotor core to the end surface of the rotor core so as to cover the outer peripheral portion of the end surface of the rotor core, it is possible to prevent the electromagnetic steel plate of the rotor core from being peeled off.

1 is a cross-sectional view including a rotation axis showing a schematic configuration of a rotating electrical machine of the present embodiment. It is sectional drawing orthogonal to a rotating shaft which shows schematic structure of the rotary electric machine of this embodiment. It is sectional drawing including a rotating shaft which shows the other structure of the rotary electric machine of this embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing a schematic configuration of a rotating electrical machine 10 according to the present embodiment, including a rotation axis of the rotating electrical machine.

  When the rotating electrical machine 10 functions as an electric motor, the rotating electrical machine 10 includes a stator 12 that forms a rotating magnetic field and a rotor 14 that rotates by the interaction between the rotating magnetic field formed by the stator 12. The stator 12 includes a substantially cylindrical stator core 16 and a coil 18 wound around the stator core, and forms a rotating magnetic field in the inner space of the cylindrical stator core 16 by passing a current through the coil. The rotor 14 includes a substantially cylindrical rotor core 20 and a hollow shaft rotor shaft 22 that is arranged coaxially with the center line of the cylinder of the rotor core 20. The rotor core 20 and the rotor shaft 22 are coupled and rotate together. The rotor core 20 is formed by laminating electromagnetic steel plates in the rotation axis direction. End plates 24 and 26 are disposed at both ends in the laminating direction, and the electromagnetic steel plates are sandwiched between the end plates 24 and 26. Permanent magnets 28 are arranged in the circumferential direction in the rotor core 20, particularly in the vicinity of the cylindrical side surface thereof, and the rotor 14 rotates due to the interaction between the permanent magnets 28 and the rotating magnetic field formed by the stator 12.

  When the rotating electrical machine 10 functions as a generator, the rotor shaft 22 is rotated by an external input, and the rotor 14 rotates. With this rotation, the permanent magnet 28 also circulates along the inner peripheral surface of the stator 12. A current is induced in the coil 18 by the magnetic field formed by the rotating permanent magnet 28.

  FIG. 2 is a schematic cross-sectional view of the rotor 14 orthogonal to the rotation axis. The structure of the rotor 14 will be further described with reference to FIGS. As shown in FIG. 2, the permanent magnet 28 has a rectangular cross section, and two permanent magnets 28 form one pole. The two permanent magnets 28 forming a set are arranged so as to form two sets of the U-shape. The opposing inner ends of the two permanent magnets are positioned radially inward of the rotor from the outer ends, and a dogleg shape is formed. The shape of the permanent magnet may be a cross-sectional shape other than a rectangle. Alternatively, one pole may be formed by one permanent magnet having a rectangular shape or other cross-sectional shape.

  The rotor core 20 is formed with a cooling flow path 30 extending in the direction of the rotation axis, particularly in parallel with the rotation axis. The cooling flow path 30 is formed by connecting holes formed in each of the electromagnetic steel plates constituting the rotor core 20. The cooling flow path 30 extends from one end of the rotor core 20 to the other end, and can be provided in a mode other than a mode parallel to the rotation axis, for example, in a spiral shape. The cooling flow path 30 and the in-axis flow path 32 in the rotor shaft 22 are connected by an introduction flow path 34 that extends in the rotor 14 in the radial direction. The introduction flow path 34 includes an introduction hole 36 formed in the rotor shaft 22 in the radial direction and an introduction groove 38 provided in one end plate 24. The introduction groove 38 is a groove formed in the surface of the end plate 24 facing the rotor core 20, and this groove is a pipe line surrounded by being covered with the end surface of the rotor core 20.

  In the end plate 24, a nozzle channel 40 having one end connected to the introduction channel 34 is formed. The nozzle channel 40 is connected to the radially outer end of the introduction channel 34. The other end of the nozzle flow path 40 is open to the end surface of the end plate 24 opposite to the rotor core 20. That is, the nozzle flow path 40 is open to one end face of the rotor 24 in the rotation axis direction.

  The coolant sent from the pump 44 reaches the cooling channel 30 and the nozzle channel 40 from the in-axis channel 32 through the introduction channel 34. The coolant is discharged from the end face of the rotor 14 through the nozzle channel 40, and the portions other than the rotor of the rotating electrical machine are cooled. When the rotor 14 is rotating, the coolant discharged from the nozzle flow path 40 is directed radially outward by centrifugal force, and is applied to the portions of the coil 18 that protrude from both ends of the stator core 16 called coil ends and are cooled. Is done. On the other hand, the coolant that has reached the cooling flow path 30 flows through the cooling flow path 30 toward the opening 42 provided in the end plate 26 on the opposite side. The coolant that has flowed out of the opening 42 cools other portions of the rotating electrical machine 10, for example, coil end portions. The coolant may be, for example, a lubricating oil that lubricates movable parts such as a bearing of a rotating electrical machine. The pump 44 may be a gear pump driven by the rotor shaft 22 or other shaft.

  Further, a hole in the radial direction may be formed in the rotor shaft 22 and the coolant discharged from the hole may be applied to the coil end.

  The rotor core 20 is formed with a cavity 46 that is a cavity extending in the direction of the rotation axis in a state where the rotor core 20 alone, that is, the permanent magnet 28 or the like is not attached. The cavity 46 may be formed by connecting holes formed in each of the electromagnetic steel plates constituting the rotor core 20. The cavity 46 extends from one end of the rotor core 20 to the other end. The cross-sectional shape of the cavity 46 may be constant in the direction in which the cavity 46 extends. A permanent magnet 28 is disposed in the cavity 46. The permanent magnet 28 is fixed to a predetermined position in the cavity 46, for example, a position adjacent to the outer surface of the cavity 46 (see FIG. 2) with an adhesive or the like. One permanent magnet 28 can be arranged in one cavity 46. At least a part of the remaining space of the cavity 46 after the permanent magnet 28 is disposed is defined as the cooling flow path 30. Therefore, like the cavity 46, the cooling flow path 30 is arranged extending in the direction in which the rotation axis of the rotor extends. The cooling flow path 30 is surrounded by the wall surface of the cavity 46 and the surface of the permanent magnet 28, and the coolant flowing through the cooling flow path 30 is in direct contact with the permanent magnet.

  A resin member 48 is formed on the outer peripheral surface of the rotor core 20 so as to cover the outer peripheral surface. The resin member 48 forms a coating layer that covers the outer peripheral surface of the rotor core. The resin member 48 can cover the entire outer peripheral surface of the rotor core 20. The resin member 48 can be formed by molding. That is, the rotor core 20 is disposed in a mold that surrounds the outer periphery of the stator core, a gap or space is formed between the outer peripheral surface of the rotor core 20 and the inner peripheral surface of the mold, and a liquid resin is poured into the resin. The resin member 48 can be formed by curing.

  As described above, the cooling channel 30 is defined by the wall surface of the cavity 46, and the coolant flowing through the cooling channel directly contacts the wall surface of the cavity 46. Since the rotor core 20 is formed by laminating electromagnetic steel plates, the end surface of the laminated electromagnetic steel plates appears on the wall surface of the cavity 46. The cooling liquid enters the gap between the laminated electromagnetic steel sheets and moves toward the outer periphery of the rotor core 20 by the centrifugal force of the rotating rotor. Further, even when the rotation of the rotor is stopped, there is a case where the gap between the electromagnetic steel sheets falls due to gravity and moves toward the lower part of the rotor. Since the outer circumferential surface of the rotor core 20 is provided with a resin member that covers the outer circumferential surface, the coolant that has entered the gap between the electromagnetic steel sheets is prevented from leaking from the outer circumferential surface of the rotor core 20. When the coolant enters the gap between the outer peripheral surface of the rotor core 20 and the inner peripheral surface of the stator core (specifically, the tip end surface of the magnetic pole), the rotor is prevented from rotating and drag loss occurs. In this case, leakage of the coolant to the outer peripheral surface of the rotor core is prevented, so that drag loss can be kept small.

  Since the resin member 48 is provided, the interval between the stator core 16 and the rotor core 20 is widened, and the magnetic resistance of this portion is increased. In order to suppress the deterioration of the magnetic characteristics, a magnetic material may be blended with the resin material constituting the resin member 48. Examples of the magnetic material include iron powder.

  FIG. 3 is a cross-sectional view showing a schematic configuration of a rotating electrical machine 50 according to another aspect of the present invention. About the same structure as the above-mentioned rotary electric machine 10, the same code | symbol is attached | subjected and the description is abbreviate | omitted. A characteristic point in this embodiment is the configuration of the rotor 52, particularly the resin member 54 and the end plates 56, 58 provided on the outer peripheral portion of the rotor 52. The resin member 54 has a peripheral surface portion 54 a that is a portion that covers the outer peripheral surface of the rotor core 20, and an end surface portion 54 b that covers the outer peripheral portion of the end surface in the rotation axis direction of the rotor core 20. The peripheral surface portion 54 a covers the outer peripheral surface of the rotor core 20 in the same manner as the resin member 48 described above. The end surface portion 54b extends from the end of the peripheral surface portion 54a so as to be wound toward the rotor core end surface. The end surface portion 54b is provided over the entire outer peripheral portion of the rotor core end surface. Moreover, it may be divided into a plurality of locations in the circumferential direction. Since the end surface portion 54b supports the outer peripheral portion of the electromagnetic steel plate of the rotor core 20, peeling of the electromagnetic steel plate at the rotor end portion can be prevented. For this reason, it becomes unnecessary to support the outer peripheral part of an electromagnetic steel plate with an end plate, and the diameter of the end plates 56 and 58 can be made smaller than the diameter of the rotor core 20. The diameter of the end plate 56 is reduced to such an extent that the introduction flow path 34 can be secured, and the diameter of the end plate 58 is further reduced. The end plate 58 can have an outer diameter located inside the cooling flow path 30. The resin member 54 can also be formed by molding.

  In the above embodiment, the coolant flowing through the cooling flow path is in direct contact with the permanent magnet, but the permanent magnet and the cooling flow path may be arranged separately. Further, in the direction in which the cooling channel extends, the cooling liquid can be in direct contact with the permanent magnet only in a part of the cooling channel.

  In the above embodiment, the outer peripheral surface of the rotor core has a cylindrical side surface shape. However, even if the outer side surface of the rotor core has an irregular shape in which grooves and depressions are provided on the cylindrical side surface, the present invention is applied to prevent leakage of the coolant. Can be suppressed. That is, by covering the surface of the rotor core that forms the grooves and the depressions with the resin member, it is possible to suppress the leakage of the coolant to the outer peripheral portion of the rotor core, that is, the gap between the rotor core and the stator core.

  DESCRIPTION OF SYMBOLS 10 Rotating electrical machine, 12 Stator, 14 Rotor, 20 Rotor core, 22 Rotor shaft, 24, 26 End plate, 28 Permanent magnet, 30 Cooling flow path, 46 Cavity, 48 Resin member, 50 Rotating electrical machine, 54 Resin member, 56, 58 end plate.

Claims (4)

A rotor core formed by laminating electromagnetic steel sheets;
Permanent magnets arranged along the circumference of the rotor core;
A cooling channel that is formed in the rotor core and through which the coolant flows, and is formed so that the coolant flowing through the cooling channel contacts the permanent magnet;
A resin member formed to cover the outer peripheral surface of the rotor core;
A rotor for a rotating electrical machine.   The rotor of a rotating electrical machine according to claim 1, wherein the resin member is blended with a magnetic material.   2. The rotor core of a rotating electrical machine according to claim 1, wherein the resin member extends from an outer peripheral surface of the rotor core to an end surface of the rotor core and covers at least a part of an outer peripheral portion of the end surface of the rotor core. A rotor core that is formed by laminating electromagnetic steel sheets, has a cooling channel formed by connecting holes formed in the electromagnetic steel sheet, and a cooling fluid flows through the cooling channel;
A resin member formed to cover the outer peripheral surface of the rotor core;
A rotor for a rotating electrical machine.

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