JP2022007439A - Rotary electric machine - Google Patents

Abstract

To provide a rotary electric machine in which a cooling liquid discharged from a rotor is discharged from an outer circumference of a stator core through a flow path disposed in the stator core in such a way that the cooling liquid that has not reached the outer circumference is prevented from staying in the stator core.SOLUTION: A yoke inner circumferential direction flow path 46 extended in a circumferential direction is disposed so as to intersect a yoke inner diameter direction flow path 44 connecting a bottom portion of a slot 34 in which a conductive wire of a coil 26 is disposed to an outer circumference of a stator core 24. A cooling liquid that has not been discharged from the yoke inner diameter direction flow path 44 on an upper part of a stator 14 flows through the yoke inner circumferential direction flow path 46, and is discharged from the separate yoke inner diameter direction flow path 44 on the lower side.SELECTED DRAWING: Figure 6

Description

The present invention relates to cooling of a rotary electric machine, particularly a rotary electric machine.

Motors that convert electrical energy into rotational kinetic energy, generators that convert rotational kinetic energy into electrical energy, and electrical equipment that functions as both electric motors and generators are known. Hereinafter, these electric devices are collectively referred to as a rotary electric machine. A typical rotary machine has a rotor and a stator arranged so as to surround the outside of the rotor, the stator is fixed, and the rotor rotates. The rotor and stator include a rotor core and a stator core that form a magnetic path, respectively. The stator has a yoke of substantially annulus or a substantially cylinder and a tooth arranged in the circumferential direction at intervals on the inner peripheral surface of the yoke to define a slot between them. A coil lead wire forming a coil is arranged in the slot.

A rotary electric machine is known in which a cooling fluid (hereinafter referred to as a coolant) is passed through the rotor core to cool the inside of the rotor core. The following Patent Document 1 shows a rotor core (21) in which a flow path (40, 41a, 41b, 42a, 42b, 43, 44a, 44b) through which a coolant flows is formed. The rotor core (21) is cooled from the inside by the coolant flowing through the flow path (40 or the like). The reference numerals in () above are the reference numerals used in the following cited document 1 and are not related to the reference numerals used in the description of the embodiments of the present application.

Japanese Unexamined Patent Publication No. 2016-54608

In Patent Document 1 described above, the coolant discharged from the rotor flows through the gap between the rotor and the stator and cools the inner peripheral surface of the stator, but it is not considered that the inside of the stator is cooled by the coolant. In particular, among the coil conductors that generate heat due to the flow of an electric current, cooling of the coil conductors at a position away from the inner circumference of the stator is not taken into consideration. If a flow path is provided in the teeth of the stator, the cooling liquid is sent to the bottom of the slot in which the coil conductor is arranged, and a flow path is provided through the yoke of the stator so that the cooling liquid is discharged from the outer peripheral surface of the stator. , Cooling of the internal configuration of the stator such as coil conductors is promoted.

However, if there is a factor that hinders the discharge of the cooling liquid from the outer peripheral surface of the stator, the desired cooling property cannot be obtained. For example, when the rotary electric machine is arranged so that its rotation axis intersects the direction of gravity, the coolant is affected by gravity at the upper part of the stator, does not reach the outer peripheral surface of the stator core, and stays without being discharged. Alternatively, backflow may occur, which may hinder the supply of new coolant and reduce the cooling performance. Further, in order to position the stator, when the case for accommodating the stator is provided with some wall surfaces that come into contact with the outer peripheral surface of the stator, the wall surfaces block the discharge port of the flow path of the coolant and the coolant is not discharged and stays. Or it may flow backward and the cooling performance may decrease.

An object of the present invention is to reduce the amount of coolant that is not discharged from the outer peripheral surface of the stator and stays or flows back.

In the rotary electric machine according to the present invention, a discharge port for discharging coolant is formed on the outer peripheral surface, and the rotor is arranged so that the rotation axes intersect with each other in the direction of gravity, and the rotor is arranged so as to surround the outer circumference of the rotor. Including a stator core, the stator core has an annular or cylindrical yoke and teeth that are spaced circumferentially arranged on the inner peripheral surface of the yoke and define a slot between them. The rotary machine further includes a coil that is partially placed in a slot and wound around a tooth.

The teeth are formed with a teeth flow path that sends the coolant discharged from the discharge port to the bottom of the slot, and the yoke has an inner peripheral surface of the yoke that extends radially and defines the bottom of the slot. A yoke inner diameter direction flow path that opens to the outer peripheral surface of the yoke and sends cooling liquid from the bottom of the slot to the outer peripheral surface of the yoke, and extends in the circumferential direction over the entire circumference, intersects the yoke inner diameter direction flow path, and intersects the yoke inner diameter direction. An inner circumferential flow path of the yoke is formed to send a part of the cooling liquid flowing through the flow path in the circumferential direction.

At the upper part of the stator, at least a part of the coolant not discharged from the outer peripheral surface of the stator core flows into the flow path in the inner peripheral direction of the yoke, so that the coolant is prevented from staying and backflowing.

It is a figure which shows typically the cross section including the rotation axis of the rotary electric machine 10 of this embodiment. It is a figure which shows typically the cross section orthogonal to the rotation axis of the rotary electric machine 10 of this embodiment, in particular, the cross section by the line II-II shown in FIG. FIG. 5 is a diagram schematically showing a cross section orthogonal to the rotation axis of the rotary electric machine 10 of the present embodiment, particularly a cross section taken along the line III-III shown in FIG. FIG. 5 is a diagram schematically showing a cross section orthogonal to the rotation axis of the rotary electric machine 10 of the present embodiment, particularly a cross section taken along the IV-IV line shown in FIG. It is a perspective view which shows typically the teeth of the stator core of the rotary electric machine 10. It is the figure which superposed the cross section by line III-III and the cross section by line IV-IV shown in FIG. It is a figure which shows the stator core positioned by the case.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 4 are views schematically showing a cross section of the rotary electric machine 10 according to the present embodiment. FIG. 1 is a cross section including the rotation axis A of the output shaft of the rotary electric machine 10, and the position of this cross section is shown by the I-I line in FIGS. 2 to 4. FIG. 2 is a cross section orthogonal to the rotation axis A, particularly a cross section taken along the line II-II in FIG. 1, FIG. 3 is a cross section orthogonal to the rotation axis A, particularly a cross section taken along the line III-III in FIG. 1, FIG. Is a cross-sectional view orthogonal to the rotation axis A, particularly a cross-sectional view taken along the line IV-IV in FIG.

The rotary electric machine 10 includes a rotor 12 and a stator 14 coaxially arranged so as to surround the rotor 12. The rotor 12 includes a substantially cylindrical rotor core 16 and a rotor shaft 18 penetrating the center of the rotor core 16. The rotor shaft 18 is the output shaft of the rotary electric machine 10. The rotor 12 is used so as to be oriented so that the rotor shaft 18 intersects the direction of gravity, for example, in the range of ± 20 ° from the horizontal, in the range of ± 10 ° from the horizontal, or horizontally. The center line of the rotor shaft 18 is the rotation axis A of the rotor 12. The direction along the rotation axis A is referred to as an axis direction, the orthogonal direction is referred to as a radial direction, and the direction along the circumference centered on the rotation axis A is referred to as a circumferential direction. The rotor core 16 is formed by laminating a rotor core plate 20 obtained by processing an electromagnetic steel sheet into a predetermined shape in the direction of the rotation axis A. A permanent magnet (not shown) is arranged near the outer peripheral surface of the rotor core 16.

The stator 14 includes a stator core 24 and a coil 26 wound around the stator core 24. The stator core 24 is formed by laminating a stator core plate 28 obtained by processing an electromagnetic steel sheet into a predetermined shape. The stator core 24 has a yoke 30 having a substantially annular or substantially cylindrical shape, and teeth 32 arranged on the inner peripheral surface of the yoke 30 at intervals along the circumferential direction. In this rotary electric machine 10, the number of teeth 32 is eight. The space between the adjacent teeth 32 is called the slot 34. The slot 34 is defined by the opposing sides of the adjacent teeth 32 and the inner peripheral surface of the yoke 30, with radial inner and axial ends open.

A coil lead wire 36 is wound around the teeth 32 to form a coil 26. The coil conductor 36 forming the coil 26 is, for example, a flat conductor having a rectangular cross section, and extends in the axial direction in the slot 34. In the rotary electric machine 10, the coil 26 is a distributed winding coil, and the coil conductors 36 are arranged in one row in the radial direction in each slot 34.

The rotor shaft 18 is a hollow shaft, and the cooling liquid is supplied through the hollow space. The coolant may be a lubricating oil that lubricates the bearings and sliding parts. The rotor shaft 18 is formed with an in-shaft flow path 38 extending along a radial direction so as to connect the hollow space and the outer peripheral surface, and the in-shaft flow path 38 is open to the outer peripheral surface of the rotor shaft 18. The coolant is sent to the outer peripheral surface of the rotor shaft 18 through the in-shaft flow path 38. The rotor core 16 is formed with a flow path 40 in the rotor core. The inner end of the rotor core inner flow path 40 in the radial direction faces the opening of the shaft inner flow path 38 formed on the outer peripheral surface of the rotor shaft 18. Further, the outer end of the rotor core inner flow path 40 in the radial direction is open to the outer peripheral surface of the rotor core 16. This opening is referred to as a discharge port 40a. The coolant is sent to the outer periphery of the rotor core 16 through the inner flow path 38 in the shaft and the inner flow path 40 in the rotor core, and is discharged from the discharge port 40a of the inner flow path 40 in the rotor core toward the stator 14.

In FIGS. 1 to 4, the rotor core inner flow path 40 is shown by a continuous flow path formed on the same rotor core plate 20 on the inner peripheral surface and the outer peripheral surface of the rotor core 16 for the sake of simplicity. In practice, the rotor core inner flow path 40 is partially divided into several flow paths, each divided flow path is formed on different rotor core plates 20, and these rotor core plates 20 are laminated adjacent to each other. It is formed by connecting various flow paths.

FIG. 5 is a perspective view schematically showing a part of the stator core 24, particularly a part including one tooth 32. The teeth 32 is divided into two in the axial direction (vertical direction in FIG. 5), and the divided portions are referred to as tooth segments 32A and 32B. A gap 42 is provided between the teeth segments 32A and 32B constituting one tooth 32. The gap 42 is provided at the same position as the discharge port 40a of the flow path in the rotor core in the axial direction, and the coolant discharged from the discharge port 40a is sent into the gap 42.

FIG. 2 is a diagram representing a cross section in which the teeth 32 are present, that is, the teeth segments 32A and 32B are included. On the other hand, FIGS. 3 and 4 are cross sections at the position of the gap 42 of the teeth 32, FIG. 3 shows a cross section at the center position of the gap 42 in the axial direction, and FIG. 4 is a cross section at a position deviated from the center. Is shown. A flow path through which the coolant flows is formed inside the yoke 30, and the flow path includes a yoke inner diameter direction flow path 44 extending in the radial direction and a yoke inner peripheral direction flow path 46 extending in the circumferential direction. Both the yoke inner diameter direction flow path 44 and the yoke inner circumference direction flow path 46 are partially formed by forming several separated flow paths on different stator core plates 28 and laminating these stator core plates 28 adjacent to each other. It is formed by connecting the flow paths.

The yoke inner diameter direction flow path 44 opens to the first portion 44A (see FIG. 4) opened at the bottom of the slot 34 at the same position as the gap 42 in the axial direction, and to the outer peripheral surface of the yoke 30, that is, the outer peripheral surface of the stator core 24. Includes a second portion 44B (see FIG. 3). By adjoining the radial outer end of the first portion 44A and the radial inner end of the second portion 44B in the axial direction, the two are connected to form a flow path connecting the inner peripheral surface and the outer peripheral surface of the yoke 30. To.

The yoke inner peripheral direction flow path 46 is formed so as to intersect the first portion 44A of the yoke inner diameter direction flow path so as to be separated from the first portion 46A extending in the circumferential direction and the second portion 44B of the yoke inner diameter direction flow path. Includes a second portion 46B that extends in the circumferential direction. The first portion 46A and the second portion 46B of the inner circumferential flow path of the yoke have a linear shape extending in the tangential direction with respect to the circumferential direction, but are not limited to this and may be formed in an arc shape. By adjoining the ends of the first portion 46A and the second portion 46B, which are adjacent to each other in the inner circumferential flow path of the yoke, in the axial direction, the two are connected to each other, and the inner circumferential flow of the yoke extends all around the inside of the yoke 30. The road 46 is formed. FIG. 6 shows how the first portion 46A and the second portion 46B of the inner circumferential flow path of the yoke are connected, the first portion 46A is shown by a broken line, and the second portion 46B is shown by a solid line. The yoke inner peripheral direction flow path 46 is formed so as to be buried in the yoke 30, that is, the circumference thereof is surrounded by the members constituting the yoke 30.

In the inner circumferential flow path 46 of the yoke, the radial dimension of the second portion 46B may be smaller than the radial dimension of the first portion 46A, and the second portion 46B may be arranged at a position farther from the rotation axis A. By increasing the magnetic material portion around the teeth 32, the cross section of the magnetic path can be increased.

The coolant discharged from the flow path 40 in the rotor core is sent to the bottom of the slot 34 through the slot 34 and the gap 42 formed by dividing the teeth 32. The gap 42 of the teeth 32 functions as a flow path in the teeth that sends the discharged coolant to the bottom of the slot 34. When fed to the bottom of the slot 34, the coolant comes into contact with the coil leads 36 to cool the coil leads 36. The coolant flows from the bottom of the slot 34 into the yoke inner diameter direction flow path 44. In the yoke inner diameter direction flow path 44 below the rotation axis A, the coolant flows through the same yoke inner diameter direction flow path 44 as it is due to the action of inertia and gravity at the time of discharge from the rotor 12, and from the outer peripheral surface of the yoke 30. It is discharged. In the yoke inner diameter direction flow path 44 above the rotation axis A, the gravity acting on the coolant acts in the opposite direction to the inertia at the time of discharge, and when the influence of gravity is large, the coolant reaches the outer peripheral surface of the yoke 30. It may not be possible. At least a portion of such coolant flows into a portion of the yoke inner peripheral flow path 46, through this flow path, downwards, and through another yoke inner diameter direction flow path 44 located below. It is discharged from the outer peripheral surface of the yoke 30.

When the stator 14 is positioned in the case for accommodating the rotary electric machine 10, the inner wall surface of the case or the wall surface of the wall erected from the case may be in contact with the outer peripheral surface of the stator core 24 for positioning. FIG. 7 shows a stator 14 positioned by the inner wall surface of the case 48. The case 48 has a positioning wall surface 48a arranged so as to surround the stator 14 along the outer peripheral surface of the stator 14, that is, the outer peripheral surface of the stator core 24. In the case of the illustrated example, the positioning wall surfaces 48a are arranged at four locations. In FIG. 7, the positioning wall surface 48a located at the right end blocks one yoke inner diameter direction flow path 44, and hinders the discharge of the cooling liquid from the positioning wall surface 48a. The coolant whose discharge from the yoke inner diameter direction flow path 44 is obstructed flows downward along the yoke inner circumference direction flow path 46, and is discharged from another yoke inner diameter direction flow path 44. Even if a part of the yoke inner diameter direction flow path 44 is blocked by the positioning wall surface 48a, the coolant can be discharged from the other yoke inner diameter direction flow path 44. By providing the flow path in the inner peripheral direction of the yoke, the degree of freedom in design is increased with respect to the position where the positioning wall surface 48a is provided. However, it is necessary that the yoke inner diameter direction flow path 44 located at the lowermost position is not blocked.

In the rotary electric machine 10, the stator core plates having the cross-sectional shape shown in FIG. 4 are arranged on both sides of the stator core plates having the cross-sectional shape shown in FIG. 3, and are located so as to sandwich the stator core plates, but they may be arranged in reverse. Further, the core plate having the cross-sectional shape shown in FIG. 4 may be arranged only on one side of the stator core plate having the cross-sectional shape shown in FIG.

The teeth may be divided into three or more tooth segments, in which case a yoke inner diameter flow path and a yoke inner circumference flow path may be formed corresponding to each of the gaps between the teeth segments. As the flow path in the teeth, instead of the gap between the teeth segments, a groove provided along the radial direction on the wall surface of the teeth defining the slot can be adopted.

When the stator core is a compact core obtained by compression molding magnetic powder, the yoke inner diameter flow path and the yoke inner circumference flow path are not divided, but are along one radial direction and one circumferential direction. It becomes possible to construct a flow path that extends straight.

10 rotary electric machine, 12 rotors, 14 stators, 16 rotor cores, 18 rotor shafts, 20 rotor core plates, 24 stator cores, 26 coils, 28 stator core plates, 30 yokes, 32 teeth, 32A teeth segments, 32B teeth segments, 34 slots, 36 coils. Conductor wire, 38 shaft inner flow path, 40 rotor core inner flow path, 40a discharge port, 42 gap (teeth inner flow path), 44 yoke inner diameter direction flow path, 46 yoke inner circumference direction flow path.

Claims (1)

A rotor that is arranged so that the axis of rotation intersects the direction of gravity and has a discharge port that discharges coolant on the outer peripheral surface.
A stator core having an annular or cylindrical yoke and teeth arranged in the circumferential direction at intervals on the inner peripheral surface of the yoke to define a slot between them, and arranged so as to surround the outer periphery of the rotor. When,
A coil, part of which is placed in the slot and wound around the teeth,
Including
A teeth flow path is formed in the teeth to send the coolant discharged from the discharge port to the bottom of the slot.
It extends radially into the yoke and opens into the inner peripheral surface of the yoke, which defines the bottom of the slot, and the outer peripheral surface of the yoke, respectively, and a coolant is applied from the bottom of the slot to the outer peripheral surface of the yoke. A yoke inner peripheral flow path that extends in the circumferential direction over the entire circumference of the yoke inner diameter direction flow path to be sent, intersects the yoke inner diameter direction flow path, and sends a part of the coolant flowing in the yoke inner diameter direction flow path in the circumferential direction. And are formed,
Rotating machine.

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