JP2019022404A - Rotor for rotary electric machine - Google Patents

Abstract

To improve cooling performance for a permanent magnet embedded in a rotor of a rotary electric machine.SOLUTION: A rotor 16 for a rotary electric machine comprises: a rotor shaft 18 with a discharge hole 22 for discharging cooling liquid in a radial direction; and a rotor core 20 that rotates integrally with the rotor shaft 18. The rotor core 20 has a slot 24 extending along an axis of rotation, and the slot 24 accommodates two permanent magnets 26. The two permanent magnets 26 are extending in the slot 24 along the axis of rotation and arranged in parallel with a distance between them, and the space between the permanent magnets 26 serves as a cooling liquid passage. An introduction member 30 is disposed on an end face of the rotor core 24. The introduction member 30 receives cooling liquid discharged from the discharge hole 22 and introduces the received cooling liquid into the cooling liquid passage between the permanent magnets 26.SELECTED DRAWING: Figure 1

Description

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

  An electric motor that converts electrical energy into rotational kinetic energy, a generator that converts rotational kinetic energy into electrical energy, and an electric device that functions as both the motor and the generator are known. Hereinafter, these electric devices are referred to as rotating electric machines. The rotating electrical machine has two members that are arranged coaxially and relatively rotate. Usually, one is fixed (stator) and the other rotates (rotor).

  There is known a permanent magnet rotating electrical machine in which a permanent magnet is arranged on a rotating side (rotor). In the permanent magnet rotating electric machine, a permanent magnet of a rotor and a coil disposed on a fixed side (stator) interact with each other through a magnetic force to operate.

  In the following Patent Document 1, a refrigerant passage (7a) that is adjacent to the permanent magnet (5) embedded in the rotor (1) and extends in the rotation axis direction is provided, and the permanent magnet (5) is cooled by the refrigerant flowing therethrough. Technology is shown. In addition, the code | symbol in () is a code | symbol used by the following patent document 1, and is not related with the code | symbol used by embodiment of this application.

JP 2003-61282 A

  In the permanent magnet arranged on the rotor, the temperature of the central part rises most and the temperature varies. It is demanded to suppress this temperature variation. In addition, it is required to efficiently introduce the coolant into the coolant channel extending in the rotation axis direction.

  An object of the present invention is to reduce the temperature variation in the permanent magnet and to efficiently introduce the coolant into the coolant channel extending in the rotation axis direction.

  A rotor of a rotating electrical machine according to the present invention includes a rotor shaft having a discharge hole for discharging a coolant in a radial direction, a rotor core integrated with the rotor shaft, and a slot that extends along the rotation axis and accommodates a permanent magnet. A rotor core having a plurality of permanent magnets extending in the rotation axis direction and arranged in parallel in the slot, and arranged in parallel in the slot, and arranged in the end face of the rotor core, receiving the coolant discharged from the discharge holes, and arranged in parallel An introduction member for introducing the received coolant into a space formed between the permanent magnets.

  By arranging the adjacent permanent magnets in parallel at an interval, the space between the permanent magnets becomes a flow path for the coolant. Further, by providing the introduction member on the end face of the rotor core, the coolant discharged from the rotor discharge hole is guided to the flow path between the permanent magnets.

  By making a plurality of permanent magnets in one slot and making one permanent magnet small and allowing the coolant to flow between the permanent magnets, variations in temperature within the permanent magnets can be suppressed. In addition, the introduction member can efficiently introduce the coolant into the coolant flow path between the permanent magnets.

It is a schematic diagram which shows schematic structure of the rotary electric machine of this embodiment. It is a figure which shows the axis orthogonal cross section of a rotor core. It is a figure which shows an example of the axis orthogonal cross section of an introduction member.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram schematically showing a cross section including a rotation axis (hereinafter referred to as an axis) of the rotating electrical machine 10 of the present embodiment. The rotating electrical machine 10 includes a stator 14 that is fixed to a housing 12 and a rotor 16 that is surrounded by the stator 14. Although the housing 12 is arranged around the stator 14 and the rotor 16, only a part of the housing 12 is shown in FIG. 1.

  The stator 14 is fixed to the housing 12 and has an annular shape or a cylindrical shape as a whole, and a plurality of coils 17 are arranged in the circumferential direction. The rotor 16 is disposed inside the stator 14 and is supported so as to be rotatable with respect to the housing 12 and the stator 14. By supplying electric power of a predetermined frequency and phase to each coil 17 of the stator 14, a rotating magnetic field is formed inside the stator 14.

  The rotor 16 includes a rotor shaft 18 supported by the housing 12 via a bearing, and an annular or cylindrical rotor core 20 that passes through the rotor shaft 18 and is coaxially disposed with the rotor shaft 18. The rotor shaft 18 is formed with a flow path for cooling liquid, and this flow path is open near the end face of the rotor core 20, and the cooling liquid is discharged from the opening toward the outside in the radial direction. Hereinafter, this opening is referred to as a discharge hole 22. A plurality of discharge holes 22 can be provided in relation to the number of permanent magnets described later. In this embodiment, the cooling fluid also serves as a lubricating oil for lubricating the bearing of the rotating electrical machine 10 and the like.

  In the vicinity of the outer periphery of the rotor core 20, a plurality of slots 24 extending over the entire axial direction of the rotor core 20 are formed, and a permanent magnet 26 is accommodated in each slot 24. The total length of the permanent magnet 26 is equal to the total length of the slot 24, that is, the dimension in the axial direction of the rotor core 20. The permanent magnet 26 forms a magnetic pole in the rotor 16 and interacts with a rotating magnetic field formed by the stator 14. The rotor 16 is rotationally driven by this interaction. When the rotor 16 is rotationally driven from the outside, the magnetic flux of the permanent magnet 26 crosses the coil of the stator 14, and an electric current is induced in the coil to generate power.

  An introduction member 30 that receives the coolant discharged from the discharge holes 22 and introduces the coolant into the coolant channel 28 (see FIG. 2) formed in the rotor core 20 is disposed on the end surface of the rotor core 20. . The introduction member 30 has a substantially annular shape, is fixed to the rotor core 20, and rotates integrally with the rotor core 20. The coolant channel 28 and the introduction member 30 will be described in detail later.

  FIG. 2 is a diagram schematically showing one pole portion of the cross section perpendicular to the axis of the rotor core 20. The rotor core 20 has a slot 24 in which a permanent magnet 26 is disposed. Three slots 24 for accommodating the permanent magnets 26 are arranged per pole. One slot 24 </ b> A is arranged in the vicinity of the outer periphery of the rotor core 20. The cross section orthogonal to the axis of the slot 24A has a shape extending in the circumferential direction. The other two slots 24B and 24C are arranged symmetrically with respect to a radius passing through the center of the slot 24A in the circumferential direction. The cross sections perpendicular to the axes of the slots 24B and 24C extend substantially along the radial direction, but do not completely coincide with the radial direction, and are inclined with respect to the radial direction. The slots 24B and 24C are inclined such that the radially inner sides thereof are closer to each other than the radius passing through the slots 24B and 24C.

  Two permanent magnets 26 are accommodated in the three slots 24A, 24B, and 24C, respectively. The two permanent magnets 26 are arranged in parallel with a space between each other, and a space between the two permanent magnets 26 forms a coolant flow path 28 through which coolant flows. The permanent magnet 26 is positioned in the slot 24 by using a stopper 32 provided on the inner wall surface of the slot 24 and fixed with an adhesive. The stop portion 32 is a bulge provided on the inner wall surface of the slot 24, and the permanent magnet 26 is positioned by coming into contact therewith. In the rotating electrical machine 10, the stopper 32 defines the position of the outer end of the two permanent magnets 26.

  Permanent magnets 26A and 26B are accommodated in the slot 24A. The two permanent magnets 26 </ b> A and 26 </ b> B each extend in the axial direction, and the length thereof is equal to the dimension of the rotor core 20 in the axial direction. Further, the two permanent magnets 26A and 26B are arranged in parallel at intervals. As a result, a coolant flow path 28A through which the coolant flows is formed between the two permanent magnets 26A and 26B. The coolant flow path 28A is defined by the mutually opposing surfaces of the two permanent magnets 26A and 26B and the radially opposing inner surfaces of the slot 24A, and is formed so as to extend over the entire rotor core 20 in the axial direction. Permanent magnets 26C and 26D are accommodated in the slot 24B, and similarly to the slot 24A, a coolant flow path 28B is formed between the two permanent magnets 26C and 26D. Permanent magnets 26E and 26F are accommodated in the slot 24C, and similarly to the slots 24A and 24B, a coolant flow path 28C is formed between the two permanent magnets 26E and 26F.

  As shown in FIG. 1, the inner wall surface 34 of the introduction member 30 is inclined with respect to the axial line so that the radius increases toward the rotor core 20 in the axial direction, and forms a part of a conical side surface. In FIG. 1, when the coolant is discharged from the discharge hole 22 as indicated by an arrow A, the coolant is received by the inner wall surface 34 of the introduction member 30, and in the direction of the rotor core 20 due to the centrifugal force and the inclination of the inner wall surface 34. Sent to the coolant flow path 28. A plurality of discharge holes 22 can be arranged on the circumference of the rotor shaft 18 so that the amount of the coolant discharged from the discharge holes 22 does not vary in the circumferential direction. For example, one discharge hole 22 can be arranged for each magnetic pole of the rotor, and one for each coolant channel 28 formed between two permanent magnets 26 in one slot 24. A discharge hole 22 can be arranged.

  By setting the number of permanent magnets accommodated in one slot 24 to two, the cross-sectional area of each of the two permanent magnets is smaller than when accommodating one. Further, the flow of the coolant between the two permanent magnets increases the surface area in contact with the coolant. By these, the temperature rise of the center part of each of two permanent magnets can be suppressed.

  FIG. 3 is a diagram illustrating another example of the introduction member. FIG. 3 is a schematic diagram showing an end face of the rotor core 20 (the permanent magnet 26 is hatched in the same manner as FIG. 2) and an axially orthogonal cross section of the introduction member 36 in the immediate vicinity of the rotor core. Further, as in FIG. 2, one pole portion is shown. The introduction member 36 has a generally annular shape as a whole, and its inner wall surface 38 has an uneven shape corresponding to the position of the coolant channel 28 in the cross section orthogonal to the axis. Specifically, the inner wall surface 38 of the introduction member 36 has a valley shape whose bottom faces the position facing the opening of each coolant flow path 28. In addition, the inner wall surface 38 of the introduction member 36 is inclined with respect to the axis so that the radius increases toward the rotor core 20 in the axial direction in the axis-containing cross section. The discharge holes 22 of the rotor shaft 18 can be provided in the same number as the coolant flow paths 28 in the rotor core 20 according to the circumferential position of the coolant flow paths 28.

  In FIG. 1, when the coolant is discharged from the discharge hole 22 as indicated by an arrow A, the coolant is received by the inner wall surface 38 of the introduction member 36, and in the direction of the rotor core 20 due to the centrifugal force and the inclination of the inner wall surface 38. Sent. Further, due to the valley shape of the inner wall surface 38 of the introduction member 36, the cooling liquid is collected from a wider range in the circumferential direction than the opening of the cooling liquid flow path 28 and sent into the cooling liquid flow path 28. The sent coolant passes through the coolant flow path 28 as indicated by arrow B and is discharged from the opening on the opposite side of the rotor core 20. The cooling liquid cools the permanent magnet 26 in the process of passing through the cooling liquid flow path 28. As the coolant flows between the two permanent magnets 26, the permanent magnets 26 are effectively cooled. Further, the introduction member 36 can efficiently introduce the coolant into the coolant flow path 28.

  Three or more permanent magnets 26 may be arranged in one slot 24. Further, the arrangement of the slots 24 in which the permanent magnets 26 are accommodated is not limited to the above example. For example, a slot containing a permanent magnet may be arranged on a line connecting the radially inner ends of the slots 24B and 24C, and these three slots may be arranged in a substantially arc shape. Alternatively, the slot 24A may be bent into a V shape, and one permanent magnet may be disposed on each of the two sides of the V shape. Further, the slot 24A may be divided into two slots, which are arranged in a V shape, and two permanent magnets may be arranged in each slot.

  DESCRIPTION OF SYMBOLS 10 Rotating electrical machine, 12 Housing, 14 Stator, 16 Rotor, 17 Coil, 18 Rotor shaft, 20 Rotor core, 22 Discharge hole, 24 slot, 26 Permanent magnet, 28 Coolant flow path, 30, 36 Introducing member, 32 Stopping part, 34,38 Inner wall surface.

Claims (1)

A rotor of a rotating electric machine,
A rotor shaft having a discharge hole for discharging the coolant in the radial direction;
A rotor core integral with the rotor shaft, the rotor core extending along a rotation axis direction and having a slot for accommodating a permanent magnet;
In the slot, a plurality of permanent magnets extending in the direction of the rotation axis and arranged in parallel at adjacent intervals;
An introduction member that is disposed on an end surface of the rotor core, receives the coolant discharged from the discharge holes, and introduces the received coolant into a space formed between the permanent magnets arranged in parallel;
A rotor for a rotating electrical machine.