JP7596852B2 - Hybrid excitation type rotating electric machine - Google Patents

Description

The present invention relates to a hybrid excitation type rotating electric machine.

Conventionally, hybrid excitation type rotating electric machines that use permanent magnets and electromagnets for the field poles are known. Patent Document 1 discloses a structure in which an excitation coil that excites a rotor core is held by a holding member, and the claws on the holding member are inserted and fixed into holes in a mounting member that is fitted into a groove in a stator core, thereby arranging the excitation coil axially opposite the rotor core.

Patent No. 5673640

However, in Patent Document 1, the excitation coil is fixed to the mounting member by the claws of the holding member, which causes problems with the strength of the fixation, such as the risk of the claws breaking. For this reason, there was previously room for improvement in the mounting of the excitation coil.

In addition, in Patent Document 1, the lead wires for passing current through the excitation coil are passed axially through the slots of the stator core and drawn out to the outside. This requires securing space within the slots of the stator core to pass the lead wires through, which reduces the space factor of the armature coil housed in the slots of the stator core. This increases the current density of the armature coil, increases copper loss, and increases heat generation in the armature coil. For this reason, there was previously room for improvement in the attachment of the excitation coil.

The present invention aims to provide a hybrid excitation type rotating electric machine with improved excitation coil installation.

A hybrid excitation type rotating electric machine according to one embodiment of the present invention comprises a rotor having a shaft extending along a central axis and a rotor core fixed to the radial outside of the shaft, a stator arranged radially outside the rotor via an air gap, and an excitation coil unit having an excitation coil that excites the rotor core, wherein the rotor has a permanent magnet that excites the rotor core, the excitation coil faces the rotor core in the axial direction, the stator has a first stator core arranged on one axial side of the excitation coil unit and a second stator core arranged on the other axial side of the excitation coil unit, the outer edge of the excitation coil unit is sandwiched between the first stator core and the second stator core around the entire circumferential circumference , and the stator has a third stator core arranged radially outside the excitation coil unit, and the third stator core is a wound core formed by winding an electromagnetic steel plate in the circumferential direction.

In the hybrid excitation type rotating electric machine of the above embodiment, the rotor has a first rotor core arranged on one axial side of the excitation coil unit and a second rotor core arranged on the other axial side of the excitation coil unit.

In the hybrid excitation type rotating electric machine of the above embodiment, the stator has a stator coil composed of a rectangular wire segment coil, and the excitation coil unit has a through hole through which the stator coil passes in the axial direction.

In the hybrid excitation type rotating electric machine according to the above aspect , at least a portion of the third stator core faces the first stator core and the second stator core in the axial direction.

In the hybrid excitation type rotating electric machine of the above embodiment, the lead wire of the excitation coil for passing current through the excitation coil extends radially outward from the excitation coil and then extends to the other axial side, the third stator core has a notch portion cut out so that the lead wire is exposed radially outward and to the other axial side, and the second stator core has a groove portion recessed radially inward from the outer circumferential surface and accommodating the lead wire.

According to one aspect of the present invention, it is possible to provide a hybrid excitation type rotating electric machine with improved excitation coil installation.

1 is a perspective view of a motor according to a first embodiment of the present invention; FIG. 2 is a right side view of the motor 100 according to the first embodiment, as viewed from the +X side. 1 is a side cross-sectional view showing a motor 100 according to a first embodiment, taken along a plane passing through a central axis J and perpendicular to an X-axis. 3 is a plan cross-sectional view of the motor 100 of the first embodiment taken along the line AA in FIG. 2. 3 is a plan sectional view of the motor 100 of the first embodiment taken along the CC section in FIG. 2. 3 is a plan cross-sectional view of the motor 100 of the first embodiment taken along the line BB in FIG. 2. FIG. 2 is a perspective view showing an exciting coil unit 350 of the motor 100 according to the first embodiment. FIG. 2 is a rear view of the motor 100 according to the first embodiment, as viewed from the +Y side.

The following describes a hybrid excitation type rotating electric machine according to an embodiment of the present invention with reference to the drawings. Note that in the following drawings, the scale and number of each structure may differ from the actual structure in order to make each configuration easier to understand.

In addition, in the drawings, an XYZ coordinate system is appropriately shown as a three-dimensional Cartesian coordinate system. In the XYZ coordinate system, the Z-axis direction is parallel to the axis of the central axis J shown in FIG. 1. The Y-axis direction is the left-right direction in FIG. 2, among the radial directions with respect to the central axis J. The X-axis direction is perpendicular to both the Z-axis direction and the Y-axis direction. In each of the X-axis, Y-axis, and Z-axis directions, the side indicated by the arrow in the drawing is the + side, and the opposite side is the - side.

In the following description, the positive side (+Z side) in the Z-axis direction is called "one side", and the negative side (-Z side) in the Z-axis direction is called "the other side". Note that one side and the other side are names used simply for explanation and do not limit the actual positional relationship and direction. Unless otherwise specified, the direction parallel to the central axis J (Z-axis direction) is simply called "axial direction", the radial direction centered on the central axis J is simply called "radial direction", and the circumferential direction centered on the central axis J, that is, around the axis of the central axis J (θ direction in Figure 1), is simply called "circumferential direction". The side approaching the central axis J in the radial direction is called "radial inner side", and the side moving away from the central axis J is called "radial outer side". In the circumferential direction, the side pointed to by the arrow shown in the figure is called the + side, and the opposite side is called the - side. The positive side in the circumferential direction (+θ side) is called "one side", and the negative side in the circumferential direction (-θ side) is called "the other side".

In this specification, "extending in the axial direction" includes not only extending strictly in the axial direction (Z-axis direction), but also extending in a direction tilted by less than 45° to the axial direction. In this specification, "extending in the radial direction" includes not only extending strictly in the radial direction, i.e., in a direction perpendicular to the axial direction (Z-axis direction), but also extending in a direction tilted by less than 45° to the radial direction. In addition, "parallel" includes not only strictly parallel, but also tilted by an angle of less than 45°.

First Embodiment
Fig. 1 is a perspective view of a motor according to a first embodiment of the present invention. The motor 100 in Fig. 1 is an example of a hybrid excitation type rotating electric machine. The motor 100 has a rotor 200 having a shaft 230 extending along a central axis J, and a stator 300 disposed radially outside the rotor 200 via an air gap. The shaft 230 is supported by a bearing (not shown) so as to be rotatable about the central axis J as a rotation axis.

Figure 2 is a right side view of the motor 100 of the first embodiment as viewed from the +X side. The shaft 230 is composed of a first shaft 231 arranged on one axial side and a second shaft 232 arranged on the other axial side. The stator 300 has a stator coil 340 composed of a rectangular wire segment coil. The stator coil 340 is an armature coil. Lead wires 355a of an excitation coil 355, which will be described in detail later, are exposed on the other axial side of the stator 300.

Figure 3 is a side cross-sectional view showing the motor 100 of the first embodiment, cut along a plane that passes through the central axis J and is perpendicular to the X-axis. The first shaft 231 has a convex portion 231a at the other axial end. The second shaft 232 has a concave portion 232a at one axial end. The first shaft 231 is fastened to the second shaft 232 by fitting the convex portion 231a into the concave portion 232a.

The motor 100 has an excitation coil unit 350. The excitation coil unit 350 has an excitation coil 355. The excitation coil unit 350 is a disk-shaped member molded from resin so that the excitation coil 355 is covered with a resin part 353. The excitation coil unit 350 has a through hole 351 that penetrates in the axial direction along the central axis J. The shaft 230 passes through the through hole 351. The inner peripheral surface of the excitation coil unit 350, i.e., the wall surface of the through hole 351, does not contact the shaft 230.

The rotor 200 has a first rotor core 210 arranged on one axial side of the excitation coil unit 350, and a second rotor core 220 arranged on the other axial side of the excitation coil unit 350. The first rotor core 210 and the second rotor core 220 are not in contact with the excitation coil unit 350. The first rotor core 210 and the second rotor core 220 may have the same shape. The first rotor core 210 and the second rotor core 220 do not have to have the same shape. The first rotor core 210 and the second rotor core 220 may have different axial lengths.

The first rotor core 210 has a through hole 212 that penetrates in the axial direction and into which the first shaft 231 fits. The first rotor core 210 is fixed to the radial outside of the first shaft 231. The first rotor core 210 is made by laminating electromagnetic steel sheets in the axial direction. The first rotor core 210 has a through hole 211 that penetrates in the axial direction. The rotor 200 has a permanent magnet 240. The first rotor core 210 accommodates the permanent magnet 240 in the through hole 211. The permanent magnet 240 excites the first rotor core 210.

The second rotor core 220 has a through hole 222 that penetrates in the axial direction and into which the second shaft 232 fits. The second rotor core 220 is fixed to the radial outside of the second shaft 232. The second rotor core 220 is made by laminating electromagnetic steel sheets in the axial direction. The second rotor core 220 has a through hole 221 (see FIG. 5) that penetrates in the axial direction. The rotor 200 has a permanent magnet 250 (see FIG. 5). The second rotor core 220 accommodates the permanent magnet 250 in the through hole 221. The permanent magnet 250 excites the second rotor core 220.

The excitation coil 355 faces the first rotor core 210 and the second rotor core 220 in the axial direction. When current is applied to the excitation coil 355, it excites the first rotor core 210 and the second rotor core 220. The excitation coil 355 is made by winding an enameled wire in the circumferential direction. The lead wire 355a, which is the end of the excitation coil 355, may be a coated conductor wire. The excitation coil 355 is wound in an alpha winding. Although one wire is shown as the lead wire 355a in the drawings, in reality the lead wire 355a is two wires at both ends of the excitation coil 355. It is desirable that the number of layers of the winding of the excitation coil 355 be two or more layers.

The stator 300 has a first stator core 310 arranged on one axial side of the excitation coil unit 350, and a second stator core 320 arranged on the other axial side of the excitation coil unit 350. The first stator core 310 is made by stacking electromagnetic steel sheets in the axial direction. The first stator core 310 is an annular member, and the first rotor core 210 is arranged to face the inner circumferential surface with an air gap between them. The second stator core 320 is made by stacking electromagnetic steel sheets in the axial direction. The second stator core 320 is an annular member, and the second rotor core 220 is arranged to face the inner circumferential surface with an air gap between them.

The stator 300 has a stator coil 340 composed of a segment coil of rectangular wire. The drawing shows the state before the other axial ends of the stator coil 340 are connected to each other. The first stator core 310 has a slot 312 that penetrates in the axial direction. The second stator core 320 has a slot 322 that penetrates in the axial direction. The slots 312 and 322 accommodate the stator coil 340. The excitation coil unit 350 has a through hole 352 that penetrates in the axial direction. The stator coil 340 penetrates through the through hole 352. That is, the stator coil 340 penetrates the first stator core 310, the excitation coil unit 350, and the second stator core 320 in that order.

The outer edge of the excitation coil unit 350 faces the first stator core 310 and the second stator core 320 in the axial direction over the entire circumference. As a result, the outer edge (radially outer edge) of the excitation coil unit 350 is sandwiched between the first stator core 310 and the second stator core 320 over the entire circumference. The first stator core 310, the excitation coil unit 350, and the second stator core 320 may be fixed with an adhesive. The first stator core 310, the excitation coil unit 350, and the second stator core 320 may be fitted into a cylindrical case (not shown) on the outer periphery in an assembled state to fix each member. The cylindrical case may constitute a stator yoke. The excitation coil unit 350 is sandwiched between the first stator core 310 and the second stator core 320, so that the attachment strength of the excitation coil 355 can be ensured.

The first stator core 310 has a groove 311 recessed radially inward from the outer circumferential surface. The second stator core 320 has a groove 321 recessed radially inward from the outer circumferential surface. The first stator core 310 and the second stator core 320 have the same shape. By making the first stator core 310 and the second stator core 320 have the same shape, the number of steps during manufacturing can be reduced. The groove 321 accommodates the lead wire 355a. By being accommodated in the groove 321, the lead wire 355a is located radially inward from the outer circumferential surface of the second stator core 320. The first stator core 310 and the second stator core 320 do not have to have the same shape. The first stator core 310 and the second stator core 320 may have different axial lengths.

The stator 300 has a third stator core 330. The third stator core 330 is disposed radially outside the excitation coil unit 350. The third stator core 330 becomes a magnetic path for the magnetic flux generated by the excitation coil 355. The third stator core 330 is a wound core formed by winding an electromagnetic steel sheet in the circumferential direction. The third stator core 330 has a cutout portion 331 cut out so that the lead wire 355a is exposed radially outward and on the other axial side. The outer peripheral surface of the excitation coil unit 350 is exposed radially outward at the cutout portion 331. The cutout portion 331 faces the groove portion 321 in the axial direction.

Figure 4 is a plan cross-sectional view of the motor 100 of the first embodiment taken along the line A-A in Figure 2. The first stator core 310 has eight grooves 311 spaced equally apart in the circumferential direction. The first stator core 310 has 48 slots 312 spaced equally apart in the circumferential direction. The first stator core 310 has teeth 313 between a slot 312 and the slot 312 adjacent to that slot 312. The first rotor core 210 has four through holes 211 spaced equally apart in the circumferential direction. The rotor 200 has four permanent magnets 240 housed in each of the four through holes 211.

Figure 5 is a plan cross-sectional view of the motor 100 of the first embodiment, cut along the CC section of Figure 2. The second stator core 320 has eight grooves 321 spaced equally apart in the circumferential direction. The second stator core 320 has 48 slots 322 spaced equally apart in the circumferential direction. The second stator core 320 has teeth 323 between a slot 322 and a slot 322 adjacent to that slot 322. The second rotor core 220 has four through holes 221 spaced equally apart in the circumferential direction. The rotor 200 has four permanent magnets 250 housed in each of the four through holes 221.

Figure 6 is a plan cross-sectional view of the motor 100 of the first embodiment taken along the line B-B in Figure 2. Figure 7 is a perspective view of the excitation coil unit 350 of the motor 100 of the first embodiment. The excitation coil unit 350 has 48 through holes 352 spaced equally apart in the circumferential direction. The slots 312, the through holes 352, and the slots 322 face each other in the axial direction. The lead wires 355a of the excitation coil 355 protrude radially outward from the resin portion 353 of the excitation coil 355.

Figure 8 is a rear view of the motor 100 of the first embodiment as seen from the +Y side. The lead wire 355a of the excitation coil 355 extends radially outward from the excitation coil 355 and then extends axially along the groove portion 321 to the other side. According to this embodiment, the lead wire 355a of the excitation coil 355 is not housed in the slots 312 and 322 of the stator 300, and therefore does not reduce the space factor of the stator coil 340.

When manufacturing the motor 100 of this embodiment, first, the excitation coil unit 350 shown in FIG. 7 is created. The excitation coil unit 350 is created by resin molding the excitation coil 355 with the resin part 353.

Then, the excitation coil unit 350 is placed radially inside the third stator core 330. At this time, the lead wire 355a protruding from the resin part 353 is aligned with the circumferential position of the notch part 331. Next, the third stator core 330 and the excitation coil unit 350 are sandwiched axially between the first stator core 310 and the second stator core 320. At this time, the lead wire 355a is aligned with the circumferential position of the groove part 321.

Then, the other axial end of the stator coil 340 is inserted from one axial side into the slot 312, and then penetrated through the through hole 352 and the slot 322. After that, the other axial end of the stator coil 340 is connected to form the armature coil into the stator 300.

Next, the first rotor core 210 is fixed to the radial outside of the first shaft 231, for example, by press-fitting, and the second rotor core 220 is fixed to the radial outside of the second shaft 232, for example, by press-fitting. Next, the first rotor core 210 is inserted from one axial side of the first stator core 310 so that the outer circumferential surface of the first rotor core 210 faces the inner circumferential surface of the first stator core 310 in the radial direction. Also, the second rotor core 220 is inserted from the other axial side of the second stator core 320 so that the outer circumferential surface of the second rotor core 220 faces the inner circumferential surface of the second stator core 320 in the radial direction. Finally, the other axial end of the first shaft 231 and the one axial end of the second shaft 232 are fastened together.

According to this embodiment, there is no need to separate the member that holds the excitation coil 355 from the member that fixes it to the first stator core 310 and the second stator core 320, and the excitation coil unit 350 can be molded as a single unit, making it easier to ensure the mechanical strength required to hold the excitation coil 355.

According to this embodiment, a space (groove 321) for passing the lead wire 355a of the excitation coil 355 can be created on the outer periphery of the second stator core 320, so the space factor of the armature coil is not reduced and heat generation is not increased.

According to this embodiment, by using a wound core as the third stator core 330, which serves as the magnetic path for the magnetic flux created by the excitation coil 355, the yield of the electromagnetic steel sheet can be improved compared to using a laminated steel sheet in which electromagnetic steel sheets are stacked in the axial direction. When using a laminated steel sheet, the electromagnetic steel sheet is punched out on the inner circumference according to the diameter of the excitation coil unit 350, and the punched out portion on the inner circumference is wasted. In contrast, with a wound core, the inner circumference of the electromagnetic steel sheet is not punched out to waste, improving the yield.

The present invention is not limited to the above-described embodiment, and various improvements and design changes may be made without departing from the spirit of the present invention. In addition, the embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims.

100...motor, 200...rotor, 230...shaft, 300...stator

Claims (5)

A rotor having a shaft extending along a central axis and a rotor core fixed to the radially outer side of the shaft;
a stator disposed radially outside the rotor with an air gap therebetween;
an excitation coil unit having an excitation coil for exciting the rotor core;
Equipped with
The rotor has a permanent magnet that excites the rotor core,
the excitation coil faces the rotor core in the axial direction,
the stator includes a first stator core disposed on one axial side of the excitation coil unit and a second stator core disposed on the other axial side of the excitation coil unit,
an outer edge of the excitation coil unit is sandwiched between the first stator core and the second stator core over the entire circumferential direction ;
the stator has a third stator core disposed radially outward of the excitation coil unit,
The third stator core is a wound core formed by winding an electromagnetic steel sheet in a circumferential direction.
Hybrid excitation type rotating electric machine. The rotor has a first rotor core arranged on one axial side of the excitation coil unit and a second rotor core arranged on the other axial side of the excitation coil unit.
2. The hybrid excitation type rotating electric machine according to claim 1. The stator has a stator coil formed of a rectangular wire segment coil,
The excitation coil unit has a through hole through which the stator coil passes in the axial direction.
3. The hybrid excitation type rotating electric machine according to claim 1 or 2. At least a portion of the third stator core faces the first stator core and the second stator core in the axial direction.
4. The hybrid excitation type rotating electric machine according to claim 1. a lead wire of the excitation coil for energizing the excitation coil extends radially outward from the excitation coil and then extends to the other axial side;
the third stator core has a cutout portion that is cut out so that the lead wire is exposed radially outward and on the other axial side,
The second stator core has a groove portion recessed radially inward from an outer circumferential surface thereof and configured to accommodate the lead wire.
5. The hybrid excitation type rotating electric machine according to claim 1 .

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