JP6993892B2 - Axial gap type rotary electric machine - Google Patents

Description

The present invention relates to an axial gap type rotary electric machine, and more particularly to a back yoke used in an axial gap type rotary electric machine.

Conventionally, an axial gap type rotary electric machine is known as a kind of permanent magnet synchronous motor. The axial gap type rotary electric machine includes a rotor and a stator having a plurality of coils, and the rotor and the stator are arranged so as to face each other with a gap in the axial direction of the rotor. Further, the stator of the axial gap type rotary electric machine further includes a back yoke for allowing the magnetic flux generated due to the energization of the plurality of coils to flow in the circumferential direction of the rotor. The back yoke is located away from the rotor in the axial direction of the rotor than the plurality of coils.

The axial gap type rotary electric machine is driven by three-phase alternating current. Therefore, the plurality of coils included in the stator of the axial gap type rotary electric machine include U-phase, V-phase, and W-phase coils as coils through which alternating currents having different phases flow. For each of the U-phase, V-phase, and W-phase coils, for example, a first coil portion wound in a predetermined direction and a direction connected to one end of the first coil portion and in the direction opposite to the first coil portion. In some cases, the second coil portion wound around the coil is arranged side by side in the circumferential direction, which is the rotation direction of the rotor.

In an axial gap type rotary electric machine, the coil generates heat due to the energization of the coil. Further, since the current flowing through the coil is an alternating current, the magnitude and direction of the magnetic flux generated due to the energization of the coil change periodically, and as a result, the energization of the coil in the stator is caused. An eddy current is generated in a portion where the magnetic flux generated is flowing (for example, a core or a back yoke around which a coil is wound), and Joule heat is generated by the eddy current. That is, the stator generates heat not only in the coil but also in the portion where the magnetic flux generated due to the energization of the coil flows. Therefore, when cooling the stator, it is required to cool not only the coil but also the portion through which the magnetic flux generated due to the energization of the coil flows.

In the axial gap type rotary electric machine described in Patent Document 1 below, a stator closing member that closes the periphery of a stator having a stator core and a stator coil is provided, and a refrigerant flows inside the stator closing member. The stator is being cooled by.

Japanese Unexamined Patent Publication No. 2005-261803

However, it is difficult to effectively cool the stator by simply flowing the refrigerant inside the stator closing member.

An object of the present invention is an axial gap type rotary electric machine including a rotor and a stator, the stator including a plurality of coils and a back yoke, and the axial gap type rotary electric machine capable of effectively cooling the stator. To provide.

In order to achieve the above object, the inventors of the present application have stated that in the axial gap type rotary electric machine as described above, it is effective to flow the refrigerant through any part of the stator in order to realize effective cooling of the stator. I examined whether it was. Specifically, among the members constituting the stator, members that can be a heat source when the axial gap type rotary electric machine is driven, that is, a plurality of coils arranged side by side in the circumferential direction of the rotor and the plurality of coils. The study focused on the fact that it is effective to flow the refrigerant so as to cool the back yoke, which allows the magnetic flux generated due to the energization of the rotor to flow in the circumferential direction of the rotor. Then, it has been found that the stator can be effectively cooled by allowing the refrigerant to flow in the radial direction of the rotor between two coils adjacent to each other in the circumferential direction of the rotor. However, in the axial gap type rotary electric machine, the space for arranging a plurality of coils and the back yoke is limited, so that the refrigerant flows between two adjacent coils in the circumferential direction in the circumferential direction of the back yoke. It is necessary to reduce the thickness of the part located between two adjacent coils (the length in the axial direction of the rotor) to secure a space for the magnetic flux to flow, and the reduction in the thickness is the reduction in the cross-sectional area of the back yoke. Therefore, the function of the back yoke (that is, the magnetic flux flows in the circumferential direction of the rotor) is reduced. Therefore, the inventors of the present application have studied a means for suppressing a decrease in the output of the axial gap type rotary electric machine regardless of a partial decrease in the thickness of the back yoke. Two of the back yokes are arranged next to each other in the circumferential direction and flow the alternating current of the same phase than the portion located between the two coils arranged next to each other in the circumferential direction and flowing alternating currents having different phases from each other. Focusing on the concentration of magnetic flux in the part located between the coils, the refrigerant flows in the part of the back yoke located between the two coils that are arranged next to each other in the circumferential direction and in which alternating currents of different phases flow. It has been found that if a space is formed, effective cooling of the stator can be realized while reducing the influence on the function of the back yoke. The present invention has been completed based on such findings.

The axial gap type rotary electric machine of the present invention includes a rotor and a stator that is arranged so as to face the rotor in the axial direction of the rotor and rotates the rotor by an electromagnetic force acting between the rotor and the rotor. The stator is different from the U-phase coil in the circumferential direction, which is the rotation direction of the rotor, the U-phase coil through which the alternating current for rotating the rotor flows, the U-phase stator core around which the U-phase coil is wound, and the U-phase coil. A V-phase coil arranged at a position and flowing an alternating current having a phase different from the alternating current flowing through the U-phase coil, a V-phase stator core around which the V-phase coil is wound, and the U-phase coil and the U-phase coil in the circumferential direction. A W-phase coil, which is arranged at a position different from the V-phase coil and has an alternating current having a phase different from the alternating current flowing through the U-phase coil and the alternating current flowing through the V-phase coil, and the W-phase coil are wound around. W-phase stator core, said U-phase coil, said V-phase coil, and a back yoke arranged away from the rotor in the axial direction from the W-phase coil, said U-phase stator core, said V-phase stator core. And each of the W-phase stator cores includes a first core portion and a second core portion arranged next to the first core portion in the circumferential direction and paired with the first core portion, and the U phase. Each of the coil, the V-phase coil, and the W-phase coil is connected to a first coil portion wound around the first core portion and one end of the first coil portion, and the first coil portion is the first. The back yoke includes a second coil portion wound around the second core portion in a direction opposite to the direction wound around the core portion, and the back yokes are arranged so as to be arranged at intervals from each other in the circumferential direction. A plurality of yoke portions are included, and the plurality of yoke portions are generated due to energization of the first coil portion of each of the U-phase coil, the V-phase coil, and the W-phase coil. Each of the first core portion and the first core portion when viewed from the axial direction so as to pass through the second core portion paired with the first core portion after the magnetic current passing through the one core portion flows in the circumferential direction. The back yoke extends in the circumferential direction while having a predetermined yoke portion thickness in the axial direction while overlapping with the second core portion forming a pair with the first core portion, and the back yoke is the circumference of the plurality of yoke portions. Two adjacent in the circumferential direction so that a first cooling space is formed between two yoke portions adjacent in the direction to allow the refrigerant for cooling the stator to flow in the radial direction of the rotor. The thickness in the axial direction is smaller than the thickness of the yoke portion between the yoke portions.

In the axial gap type rotary electric machine, the U-phase coil, the V-phase coil, and the W-phase coil are formed by flowing the refrigerant through the first cooling space formed between two adjacent yoke portions in the circumferential direction of the back yoke. Of these, the refrigerant passes between two coils adjacent to each other in the circumferential direction. Therefore, the U-phase coil, the V-phase coil, the W-phase coil, and the back yoke, which can be heat sources when the axial gap type rotary electric machine is being driven, can be cooled at the same time. As a result, the stator can be effectively cooled.

Here, in the axial gap type rotary electric machine, between two coils of the U-phase coil, the V-phase coil, and the W-phase coil that are adjacent to each other in the circumferential direction, that is, between two coils in which alternating currents having different phases flow. Since the first cooling space is formed in the back yoke, between the first coil portion and the second coil portion of each of the U-phase coil, the V-phase coil, and the W-phase coil in the back yoke, that is, the alternating current having the same phase. It is possible to avoid obstructing the concentration of the magnetic flux in the portion located between the two coils through which the current flows. As a result, it is possible to reduce the influence on the function of the back yoke and suppress the decrease in the output of the axial gap type rotary electric machine.

In the axial gap type rotary electric machine, the axial thickness of the back yoke is smaller than the yoke thickness between two adjacent yoke portions in the circumferential direction. Also included is an aspect of zero between two adjacent yokes.

That is, the back yoke may have a mode in which the plurality of yoke portions are separated from each other in the circumferential direction.

In the above aspect, since the volume of the first cooling space can be maximized, more refrigerant can flow into the first cooling space.

Alternatively, the back yoke is interposed between the two yoke portions adjacent to each other in the circumferential direction so as to allow the magnetic flux to flow between the two yoke portions adjacent to each other in the circumferential direction. A connection portion connecting the yoke portions may be further included, and the axial thickness of the connection portion may be smaller than the yoke portion thickness.

In the above aspect, since the connection portion existing between the two yoke portions adjacent to each other in the circumferential direction allows the magnetic flux to flow in the circumferential direction, it is possible to reduce the torque ripple when the rotor rotates. can.

In the axial gap type rotary electric machine, preferably, a plurality of cooling pipes are further provided, which are arranged between two yoke portions adjacent to each other in the circumferential direction and allow the refrigerant to flow into the first cooling space.

In the above aspect, since it is possible to prevent the refrigerant from coming into direct contact with the stator, it is possible to avoid requiring the axial gap type rotary electric machine to have a sealing property that prevents the refrigerant from leaking to the outside of the axial gap type rotary electric machine. can do.

In the axial gap type rotary electric machine, preferably, at least one of the first core portion and the second core portion has a through hole extending in the axial direction and penetrating the stator core. A second cooling space is formed in each of the plurality of yoke portions, which is connected to the end of the through hole on the back yoke side so that the refrigerant flows in the through hole and allows the refrigerant to flow. As described above, a portion having a thickness smaller than the thickness of the yoke portion is formed in the axial direction.

In the above aspect, since the refrigerant flows in at least one of the first core portion and the second core portion, the stator core can be directly cooled by the refrigerant.

According to the axial gap type rotary electric machine of the present invention, the stator can be effectively cooled while suppressing a decrease in the output of the axial gap type rotary electric machine.

It is sectional drawing which shows the axial gap type rotary electric machine by embodiment of this invention. It is an exploded perspective view which shows the axial gap type rotary electric machine by embodiment of this invention. It is a perspective view which shows the state which the rotor is arranged between two stators. It is a top view which shows the positional relationship between a plurality of coils provided in a stator, and a back yoke in an axial gap type rotary electric machine according to an embodiment of the present invention. FIG. 5 is a plan view showing a positional relationship between a plurality of coils included in a stator and a back yoke in an axial gap type rotary electric machine according to a modification 1 of the embodiment of the present invention. FIG. 5 is a perspective view showing a state in which a plurality of cooling pipes are arranged in each of two stators in the axial gap type rotary electric machine according to the second modification of the embodiment of the present invention. It is a perspective view which shows the back yoke provided with the stator in the axial gap type rotary electric machine which concerns on the modification 3 of the Embodiment of this invention. It is a perspective view which shows the plurality of stator cores provided in the stator in the axial gap type rotary electric machine which concerns on the modification 3 of the Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

An axial gap type DC brushless motor 10 (hereinafter, simply referred to as a motor 10) as an axial gap type rotary electric machine according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a cross-sectional view of the motor 10. FIG. 2 is an exploded perspective view of the motor 10.

In the following description, the axial direction, the radial direction, and the circumferential direction refer to the axial direction, the radial direction, and the circumferential direction of the rotor 30 included in the motor 10. That is, the radial direction corresponds to the radial direction of rotation of the rotor 30, and the circumferential direction corresponds to the circumferential direction of rotation of the rotor 30.

The motor 10 includes a rotor 30 fixed to a rotor shaft (not shown), two stators 40 arranged on both sides of the rotor 30 in the axial direction, and a casing 50 accommodating the rotor 30 and the stator 40.

The casing 50 includes a drum 51, a first end wall 52, a first inner cylinder wall 53, a second end wall 54, and a second inner cylinder wall 55. The drum 51 has a structure in which a plurality of (two in the present embodiment) tubular walls 511 and 512 arranged side by side in the axial direction are connected to each other. The drum 51 surrounds the rotor 30 and the stator 40. The first end wall 52 is attached to one end in the axial direction of the drum 51 (specifically, one end in the axial direction of the cylinder wall 511) to close the opening on the one end side. The first inner cylinder wall 53 is attached to the central portion of the first end wall 52 and is located inside the drum 51 (specifically, the cylinder wall 511). The second end wall 54 is attached to the other end in the axial direction of the drum 51 (specifically, the other end in the axial direction of the cylinder wall 512) to close the opening on the other end side. The second inner cylinder wall 55 is attached to the central portion of the second end wall 54 and is located inside the drum 51 (specifically, the cylinder wall 512).

The rotor shaft fixed to the rotor 30 extends in the axial direction of the rotor 30. An axial end of a rotor shaft (not shown) is supported by a first end wall 52 and a first inner cylinder wall 53 via bearings. The other end in the axial direction of the rotor shaft (not shown) is supported by the second end wall 54 and the second inner cylinder wall 55 via bearings.

The rotor 30 includes a disk-shaped base member 32 and a plurality of permanent magnets 34 held by the base member 32.

The stator 40 is arranged so as to face the rotor 30 in the axial direction of the rotor 30. The stator 40 rotates the rotor 30 by an electromagnetic force acting between the stator 40 and the rotor 30. In FIGS. 1 and 2, the plurality of coils 42 (FIGS. 3 and 4) included in the stator 40 are resin-molded.

The stator 40 will be described with reference to FIGS. 3 and 4. FIG. 3 is a perspective view showing a state in which the rotor 30 is arranged between the two stators 40. FIG. 4 is a plan view showing the positional relationship between the plurality of coils 42 included in the stator 40, the plurality of stator cores 44, and the back yoke 46.

The stator 40 includes a plurality of coils 42, a plurality of stator cores 44, and a back yoke 46. These will be described below.

The plurality of coils 42 have a phase different from that of the U-phase coil 42U through which the alternating current for rotating the rotor 30 flows and the alternating current flowing through the U-phase coil 42U arranged at a position different from that of the U-phase coil 42U in the circumferential direction. The alternating current and V-phase coil 42V are arranged at different positions from the V-phase coil 42V through which the alternating current flows and the U-phase coil 42U and the V-phase coil 42V in the circumferential direction which is the rotation direction of the rotor 30, and flow through the U-phase coil 42U. Includes a W-phase coil 42W through which an alternating current with a phase different from the alternating current flowing through the current flows.

In the plurality of coils 42, the U-phase coil 42U, the V-phase coil 42V, and the W-phase coil 42W are arranged side by side in the circumferential direction in this order. Further, in the plurality of coils 42, a coil group composed of a U-phase coil 42U, a V-phase coil 42V, and a W-phase coil 42W is arranged side by side in the circumferential direction. That is, the plurality of coils 42 include a plurality of coil groups. In other words, the plurality of coils 42 includes at least one U-phase coil 42U, at least one V-phase coil 42V, and at least one W-phase coil 42W.

The plurality of stator cores 44 include a U-phase stator core 44U around which the U-phase coil 42U is wound, a V-phase stator core 44V around which the V-phase coil 42V is wound, and a W-phase stator core 44W around which the W-phase coil 42W is wound. including. That is, the plurality of stator cores 44 include at least one U-phase stator core 44U, at least one V-phase stator core 44V, and at least one W-phase stator core 44W.

The back yoke 46 is arranged more axially away from the rotor 30 than the plurality of coils 42. That is, the back yoke 46 included in the stator 40 located in the first cylinder wall 511 is arranged between the rotor 30 and the first end wall 52. The back yoke 46 included in the stator 40 located in the second cylinder wall 512 is arranged between the rotor 30 and the second end wall 54.

The U-phase coil 42U is wound around the U-phase stator core 44U. An alternating current for rotating the rotor 30 flows through the U-phase coil 42U.

The V-phase coil 42V is wound around the V-phase stator core 44V. The V-phase coil 42V is arranged at a position different from that of the U-phase coil 42U in the circumferential direction. Specifically, the V-phase coil 42V is arranged next to the U-phase coil 42U in the circumferential direction. An alternating current having a phase different from the alternating current flowing through the U-phase coil 42U flows through the V-phase coil 42V.

The W-phase coil 42W is wound around the W-phase stator core 44W. The W-phase coil 42W is arranged at a position different from that of the U-phase coil 42U and the V-phase coil 42V in the circumferential direction. Specifically, the W-phase coil 42W is arranged next to the V-phase coil 42V and next to the U-phase coil 42U in the circumferential direction. That is, the W-phase coil 42W is arranged between the V-phase coil 42V and the U-phase coil 42U in the circumferential direction. An alternating current having a phase different from the alternating current flowing through the U-phase coil 42U and the alternating current flowing through the V-phase coil 42V flows through the W-phase coil 42W.

Here, each of the U-phase stator core 44U, the V-phase stator core 44V, and the W-phase stator core 44W is arranged next to the first core portion 441 in the circumferential direction and forms a pair with the first core portion 441. Includes a second core portion 442.

On one side of the first core portion 441 of the U-phase stator core 44U in the circumferential direction, there is a second core portion 442 paired with the first core portion 441, that is, a U-phase stator core 44U having the first core portion 441. The included second core portion 442 is located. On the other side of the first core portion 441 of the U-phase stator core 44U in the circumferential direction, the second core portion 442 included in the W-phase stator core 44W located next to the U-phase stator core 44U is located.

The first core portion 441 included in the V-phase stator core 44V located next to the U-phase stator core 44U is located on one side in the circumferential direction of the second core portion 442 of the U-phase stator core 44U. On the other side of the second core portion 442 of the U-phase stator core 44U in the circumferential direction, there is a first core portion 441 paired with the second core portion 442, that is, a U-phase stator core 44U having the second core portion 442. The included first core portion 441 is located.

On one side in the circumferential direction of the first core portion 441 of the V-phase stator core 44V, there is a second core portion 442 paired with the first core portion 441, that is, a V-phase stator core 44V having the first core portion 441. The included second core portion 442 is located. The second core portion 442 included in the U-phase stator core 44U located next to the V-phase stator core 44V is located on the other side in the circumferential direction of the first core portion 441 of the V-phase stator core 44V.

On one side in the circumferential direction of the second core portion 442 of the V-phase stator core 44V, the first core portion 441 included in the W-phase stator core 44W located next to the V-phase stator core 44V is located. On the other side of the second core portion 442 of the V-phase stator core 44V in the circumferential direction, there is a first core portion 441 paired with the second core portion 442, that is, a V-phase stator core 44V having the second core portion 442. The included first core portion 441 is located.

On one side in the circumferential direction of the first core portion 441 of the W-phase stator core 44W, a second core portion 442 paired with the first core portion 441, that is, a W-phase stator core 44W having the first core portion 441 is formed. The included second core portion 442 is located. The second core portion 442 included in the V-phase stator core 44V located next to the W-phase stator core 44W is located on the other side in the circumferential direction of the first core portion 441 of the W-phase stator core 44W.

The first core portion 441 included in the U-phase stator core 44U located next to the W-phase stator core 44W is located on one side in the circumferential direction of the second core portion 442 of the W-phase stator core 44W. On the other side of the second core portion 442 of the W phase stator core 44W in the circumferential direction, the first core portion 441 paired with the second core portion 442, that is, the W phase stator core 44W having the second core portion 442 The included first core portion 441 is located.

Further, each of the U-phase coil 42U, the V-phase coil 42V, and the W-phase coil 42W is connected to one end of the first coil portion 421 wound around the first core portion 441 and the first coil portion 421. Includes a second coil portion 422 that is wound around the second core portion 442 in a direction opposite to the direction in which the portion 421 is wound around the first core portion 441.

The U-phase coil 42U includes a first coil portion 421 and a second coil portion 422 connected to one end of the first coil portion 421. The first coil portion 421 of the U-phase coil 42U is wound around the first core portion 441 of the U-phase stator core 44U. The second coil portion 422 of the U-phase coil 42U is wound around the second core portion 442 of the U-phase stator core 44U. The second coil portion 422 of the U-phase coil 42U is wound in the direction opposite to that of the first coil portion 421 of the U-phase coil 42U. That is, in the second coil portion 422 of the U-phase coil 42U, an alternating current flows in the direction opposite to that of the first coil portion 421 of the U-phase coil 42U. Therefore, the direction in which the magnetic flux generated due to the energization of the second coil portion 422 of the U-phase coil 42U flows through the second core portion 442 is due to the energization of the first coil portion 421 of the U-phase coil 42U. The direction in which the magnetic flux generated is opposite to the direction in which the magnetic flux is generated flows through the first core portion 441.

The V-phase coil 42V includes a first coil portion 421 and a second coil portion 422 connected to one end of the first coil portion 421. The first coil portion 421 of the V-phase coil 42V is wound around the first core portion 441 of the V-phase stator core 44V. The second coil portion 422 of the V-phase coil 42V is wound around the second core portion 442 of the V-phase stator core 44V. The second coil portion 422 of the V-phase coil 42V is wound in the direction opposite to that of the first coil portion 421 of the V-phase coil 42V. That is, in the second coil portion 422 of the V-phase coil 42V, an alternating current flows in the direction opposite to that of the first coil portion 421 of the V-phase coil 42V. Therefore, the direction in which the magnetic flux generated by the energization of the second coil portion 422 of the V-phase coil 42V flows through the second core portion 442 is due to the energization of the first coil portion 421 of the U-phase coil 42U. The direction in which the magnetic flux generated is opposite to the direction in which the magnetic flux is generated flows through the first core portion 441.

The W-phase coil 42W includes a first coil portion 421 and a second coil portion 422 connected to one end of the first coil portion 421. The first coil portion 421 of the W-phase coil 42W is wound around the first core portion 441 of the W-phase stator core 44W. The second coil portion 422 of the W-phase coil 42W is wound around the second core portion 442 of the W-phase stator core 44W. The second coil portion 422 of the W-phase coil 42W is wound in the direction opposite to that of the first coil portion 421 of the W-phase coil 42W. That is, in the second coil portion 422 of the W-phase coil 42V, an alternating current flows in the direction opposite to that of the first coil portion 421 of the W-phase coil 42W. Therefore, the direction in which the magnetic flux generated by the energization of the second coil portion 422 of the W-phase coil 42W flows through the second core portion 442 is due to the energization of the first coil portion 421 of the W-phase coil 42W. The direction in which the magnetic flux generated is opposite to the direction in which the magnetic flux is generated flows through the first core portion 441.

The back yoke 46 is arranged farther from the rotor 30 in the axial direction of the rotor 30 than the U-phase coil 42U, the V-phase coil 42V, and the W-phase coil 42W.

The back yoke 46 includes a plurality of yoke portions 461. The plurality of yoke portions 461 are arranged side by side in the circumferential direction. The plurality of yoke portions 461 are generated due to energization of the first coil portion 421 of each of the U-phase coil 42U, the V-phase coil 42V, and the W-phase coil 42W, and the magnetic flux passing through the first core portion 441. Is paired with the first core portion 441 and the first core portion 441 when viewed from the axial direction so as to pass through the second core portion 442 which is paired with the first core portion 441 after flowing in the circumferential direction. It overlaps with the second core portion 442 and extends in the circumferential direction while having a predetermined yoke portion thickness in the axial direction.

The plurality of yoke portions 461 overlap the yoke portion 461U that overlaps the U-phase stator core 44U when viewed from the axial direction, the yoke portion 461V that overlaps the V-phase stator core 44V when viewed from the axial direction, and the W-phase stator core 44W when viewed from the axial direction. Includes yoke portion 461W. In other words, the plurality of yoke portions 461 have a yoke portion 461U located at a position corresponding to the U-phase stator core 44U in the circumferential direction, and a yoke portion 461V located at a position corresponding to the V-phase stator core 44V in the circumferential direction. It includes a W-phase stator core 44W and a yoke portion 461W at a position corresponding to the W-phase stator core 44W in the circumferential direction.

In the plurality of yoke portions 461, the yoke portions 461U, the yoke portions 461V, and the yoke portions 461W are arranged side by side in the circumferential direction in this order. Further, in the plurality of yoke portions 461, a group of yoke portions composed of a yoke portion 461U, a yoke portion 461V, and a yoke portion 461W are arranged side by side in the circumferential direction. That is, the plurality of yoke portions 461 include a plurality of yoke portions. In other words, the plurality of yoke portions 461 include at least one yoke portion 461U, at least one yoke portion 461V, and at least one yoke portion 461W.

In the yoke portion 461U, the first core portion 441 in which the first coil portion 421 of the U-phase coil 42U is wound and the second coil portion 422 of the U-phase coil 42U are wound in the yoke portion 461U. It overlaps with the second core portion 442. The yoke portion 461U extends in the circumferential direction while having a predetermined yoke portion thickness in the axial direction. The thickness of the yoke portion 461U is constant over the entire yoke portion 461U.

In the yoke portion 461V, the first core portion 441 around which the first coil portion 421 of the V-phase coil 42V is wound and the second coil portion 422 of the V-phase coil 42V are wound around the yoke portion 461V. It overlaps with the second core portion 442. The yoke portion 461V extends in the circumferential direction while having a predetermined yoke portion thickness in the axial direction. The thickness of the yoke portion 461V is constant over the entire yoke portion 461V. The thickness of the yoke portion 461V is the same as the thickness of the yoke portion 461U. The shape and size of the yoke portion 461V are the same as the shape and size of the yoke portion 461U.

In the yoke portion 461W, the first core portion 441 around which the first coil portion 421 of the W-phase coil 42W is wound and the second coil portion 422 of the W-phase coil 42W are wound around the yoke portion 461W. It overlaps with the second core portion 442. The yoke portion 461W extends in the circumferential direction while having a predetermined yoke portion thickness in the axial direction. The thickness of the yoke portion 461W is constant over the entire yoke portion 461W. The thickness of the yoke portion 461W is the same as the thickness of the yoke portion 461U and the thickness of the yoke portion 461V. The shape and size of the yoke portion 461W are the same as the shape and size of the yoke portion 461U and the yoke portion 461V.

The back yoke 46 further includes a plurality of connecting portions 462. The plurality of connecting portions 462 are formed between two yoke portions 461 adjacent to each other in the circumferential direction, and connect the two yoke portions 461 adjacent to each other in the circumferential direction. Each of the plurality of connecting portions 462 extends in the radial direction while having a thickness smaller than the thickness of the yoke portion in the axial direction.

The plurality of connection portions 462 connect the connection portion 4621 that connects the yoke portion 461U and the yoke portion 461V, the connection portion 4622 that connects the yoke portion 461V and the yoke portion 461W, and the yoke portion 461W and the yoke portion 461U. Each includes at least one connecting portion 4623.

The connecting portion 4621 connects two yoke portions 461U and 461V adjacent to each other in the circumferential direction over the entire length in the radial direction. The axial thickness of the connecting portion 4621 is smaller than the axial thickness of the yoke portion 461. The axial thickness of the connecting portion 4621 is constant over the entire connecting portion 4621.

The connecting portion 4622 connects two yoke portions 461V and 461W adjacent to each other in the circumferential direction over the entire length in the radial direction. The axial thickness of the connecting portion 4622 is smaller than the axial thickness of the yoke portion 461. The axial thickness of the connecting portion 4622 is constant over the entire connecting portion 4622. The shape and size of the connecting portion 4622 are the same as the shape and size of the connecting portion 4621.

The connecting portion 4623 connects two yoke portions 461W and 461U adjacent to each other in the circumferential direction over the entire length in the radial direction. The axial thickness of the connecting portion 4623 is smaller than the axial thickness of the yoke portion 461. The axial thickness of the connecting portion 4623 is constant over the entire connecting portion 4623. The shape and size of the connecting portion 4623 are the same as the shape and size of the connecting portion 4621 and the connecting portion 4622.

Each of the back yokes 46 is axially oriented so as to allow the refrigerant for cooling the stator 40 to flow radially between the two yoke portions 461 adjacent to each other in the circumferential direction among the plurality of yoke portions 461. A plurality of first cooling spaces 463 extending in the radial direction are formed in the yoke portion having a length equal to or less than the thickness of the yoke portion.

Each of the plurality of first cooling spaces 463 is formed between two yoke portions 461 adjacent to each other in the circumferential direction among the plurality of yoke portions 461. That is, the plurality of first cooling spaces 463 are formed at positions corresponding to the plurality of connecting portions 462 in the circumferential direction. That is, each of the plurality of first cooling spaces 463 extends in the radial direction while having an axial length corresponding to the difference between the axial thickness of the yoke portion 461 and the axial thickness of the connecting portion 462. There is.

The plurality of first cooling spaces 463 include a first cooling space 4631 formed between the yoke portion 461U and the yoke portion 461V, and a first cooling space 4632 formed between the yoke portion 461V and the yoke portion 461W. , Each includes at least one first cooling space 4633 formed between the yoke portion 461W and the yoke portion 461U. That is, the plurality of first cooling spaces 463 are the first cooling space 4631 formed at a position corresponding to the connection portion 4621 in the circumferential direction, and the first cooling space formed at a position corresponding to the connection portion 4622 in the circumferential direction. Each includes at least one 4632 and a first cooling space 4633 formed at a position corresponding to the connection portion 4623 in the circumferential direction.

The first cooling space 4631 extends in the radial direction while having an axial length corresponding to the difference between the axial thickness of the yoke portion 461 and the axial thickness of the connecting portion 4621. That is, the first cooling space 4631 extends in the radial direction while having an axial length smaller than the axial thickness of the yoke portion 461. The first cooling space 4631 allows the refrigerant for cooling the stator 40 to flow in the radial direction.

The first cooling space 4632 extends in the radial direction while having an axial length corresponding to the difference between the axial thickness of the yoke portion 461 and the axial thickness of the connecting portion 4622. That is, the first cooling space 4632 extends in the radial direction while having an axial length smaller than the axial thickness of the yoke portion 461. The first cooling space 4632 allows the refrigerant for cooling the stator 40 to flow in the radial direction. The volume of the first cooling space 4632 is the same as the volume of the first cooling space 4631.

The first cooling space 4633 extends in the radial direction while having an axial length corresponding to the difference between the axial thickness of the yoke portion 461 and the axial thickness of the connecting portion 4623. That is, the first cooling space 4633 extends in the radial direction while having an axial length smaller than the axial thickness of the yoke portion 461. The first cooling space 4633 allows the refrigerant for cooling the stator 40 to flow in the radial direction. The volume of the first cooling space 4633 is the same as the volume of the first cooling space 4631 and the first cooling space 4632.

Subsequently, cooling of the stator 40 using the refrigerant in the motor 10 will be described with reference to FIG. 1.

The motor 10 has two stators 40. The two stators 40 are cooled by separate refrigerants. Specifically, one stator 40 (stator 40 arranged in the first cylinder wall 511) is cooled by the refrigerant introduced into the casing 50 from the refrigerant introduction pipe 561 provided in the first cylinder wall 511. Ru. The other stator 40 (stator 40 arranged in the second cylinder wall 512) is cooled by the refrigerant introduced into the casing 50 from the refrigerant introduction pipe 562 provided in the second cylinder wall 512. More details are as follows.

First, cooling of one of the stators 40 will be described. The refrigerant introduced into the casing 50 from the refrigerant introduction pipe 561 flows through the space formed between the one stator 40 and the first end wall 52. At that time, the refrigerant flows from the outside to the inside in the radial direction through the plurality of first cooling spaces 463 formed in the back yoke 46 included in the one stator 40. The refrigerant that has passed through the plurality of first cooling spaces 463 is discharged from the tubular communication passage formed between the first inner cylinder wall 53 and the stator 40 into the space where the rotor 20 is arranged, and comes into contact with the rotor 20. .. At this time, since the rotor 20 is rotating, the refrigerant in contact with the rotor 20 is scattered around the rotor 20 and then is provided in the refrigerant discharge pipe 571 and the second cylinder wall 512 provided in the first cylinder wall 511. It is discharged to the outside of the casing 50 from the refrigerant discharge pipe 572.

Subsequently, cooling of the other stator 40 will be described. The refrigerant introduced into the casing 50 from the refrigerant introduction pipe 562 flows through the space formed between the other stator 40 and the second end wall 54. At that time, the refrigerant flows from the outside to the inside in the radial direction through the plurality of first cooling spaces 463 formed in the back yoke 46 included in the other stator 40. The refrigerant that has passed through the plurality of first cooling spaces 463 is discharged from the tubular communication passage formed between the second inner cylinder wall 55 and the stator 40 into the space where the rotor 20 is arranged, and comes into contact with the rotor 20. .. At this time, since the rotor 20 is rotating, the refrigerant in contact with the rotor 20 is scattered around the rotor 20 and then is provided in the refrigerant discharge pipe 571 and the second cylinder wall 512 provided in the first cylinder wall 511. It is discharged to the outside of the casing 50 from the refrigerant discharge pipe 572.

In the motor 10, the U-phase coil 42U, the V-phase coil 42V, and W are caused by the refrigerant flowing through the first cooling space 463 formed between the two yoke portions 461 adjacent to each other in the circumferential direction of the back yoke 46. The refrigerant passes between two adjacent coils of the phase coil 42W in the circumferential direction. Therefore, the U-phase coil 42U, the V-phase coil 42V, the W-phase coil 42W, and the back yoke 46, which can be heat sources when the motor 10 is being driven, can be cooled at the same time. As a result, the stator 40 can be effectively cooled.

Here, in the motor 10, the U-phase coil 42U, the V-phase coil 42V, and the W-phase coil 42W are located between two adjacent coils in the circumferential direction, that is, between two coils in which alternating currents having different phases flow. Since the first cooling space 463 is formed, between the first coil portion 421 and the second coil portion 422 (that is, each of the U-phase coil 42U, the V-phase coil 42V, and the W-phase coil 42W) of the back yoke 46. , It is possible to avoid obstructing the concentration of magnetic flux in the portion located (between two coils through which alternating currents of the same phase flow). As a result, it is possible to reduce the influence on the function of the back yoke 46 and suppress the decrease in the output of the motor 10.

Further, in the motor 10, the magnetic flux exists between the two yoke portions 461 of the back yoke 46 adjacent to each other in the circumferential direction so as to allow the magnetic flux to flow between the two yoke portions 461 adjacent to each other in the circumferential direction. The connecting portion 462 connects two yoke portions 461 adjacent to each other in the circumferential direction. Therefore, in the motor 10, the connecting portion 462 existing between the two yoke portions 461 adjacent to each other in the circumferential direction allows the magnetic flux to flow in the circumferential direction. As a result, the torque ripple when the rotor 30 rotates can be reduced.

Further, the direction in which the refrigerant flows in each of the plurality of first cooling spaces 463 so as to allow the refrigerant flowing in each of the plurality of first cooling spaces 463 to come into contact with the rotor 30 in the motor 10. A refrigerant flow path (cylindrical communication passage provided between the first inner cylinder wall 53 and the stator 40) is formed which is connected to the downstream end portion of the above and extends in the axial direction. Therefore, in the motor 10, the rotor 30 can be cooled by using the refrigerant that cools the stator 40.

[Modification 1 of the embodiment]
In the above embodiment, two yoke portions 461 adjacent to each other in the circumferential direction are connected by a connecting portion 462. That is, the connecting portion 462 has a thickness in the axial direction so as to allow magnetic flux to flow between two yoke portions 461 adjacent to each other in the circumferential direction.

In the above embodiment, the thickness of the connecting portion 462 may be zero. That is, the mode may be such that the connecting portion 462 does not exist.

Such an embodiment will be described with reference to FIG. FIG. 5 is a plan view showing the positional relationship between the plurality of coils 42, the plurality of stator cores 44, and the back yoke 46 in this modification.

In the example shown in FIG. 5, two yoke portions 461 adjacent to each other in the circumferential direction are not connected by the connecting portion 462. That is, the plurality of yoke portions 461 are separated from each other in the circumferential direction. Therefore, the axial length of the first cooling space 463 formed between the two yoke portions 461 adjacent to each other in the circumferential direction is the same as the axial thickness (that is, the yoke portion thickness) of the yoke portion 461. .. That is, in this modification, the volume of the first cooling space 463 is larger than that of the above embodiment.

The plurality of yoke portions 461 are fixed to the casing 50 to maintain a state of being divided in the circumferential direction.

In such an embodiment, the volume of the first cooling space 463 can be maximized, so that more refrigerant can flow into the first cooling space 463. Therefore, the cooling efficiency can be improved.

Further, in the above aspect, since the plurality of yoke portions 461 can be formed by different members, the back yoke 46 can be easily manufactured.

[Modification 2 of the embodiment]
In the above embodiment, the refrigerant directly flows in the first cooling space 463. That is, the refrigerant comes into direct contact with the stator 40.

In the above embodiment, the refrigerant may flow in the first cooling space 463. That is, the refrigerant does not have to come into direct contact with the stator 40.

Such an embodiment will be described with reference to FIG. FIG. 6 is a perspective view showing a state in which a plurality of cooling pipes 47 are arranged on the stator 40.

In the example shown in FIG. 6, the plurality of cooling pipes 47 are arranged between two yoke portions 461 adjacent to each other in the circumferential direction so as to allow the refrigerant to flow into the first cooling space 463. A part of the cooling pipe 47 may be located outside the first cooling space 463. The refrigerant flows through the first cooling space 463 by flowing through the cooling pipe 47. The cooling pipe 47 forms a flow path for the refrigerant.

In such an embodiment, since the cooling pipe 47 forms the flow path of the refrigerant, it is possible to avoid that the casing of the motor is required to have a special sealing property as compared with the above-described embodiment.

Further, in the above aspect, since the flow path of the refrigerant is formed by the cooling pipe 47, the refrigerant can be flowed in a desired path as compared with the above-described embodiment.

[Modification 3 of the embodiment]
In the above embodiment, the refrigerant is allowed to flow inside at least one of the first core portion 441 and the second core portion 442 of each of the U-phase stator core 44U, the V-phase stator core 44V, and the W-phase stator core 44W. May be good. Such an embodiment will be described with reference to FIGS. 7 and 8.

In the examples shown in FIGS. 7 and 8, through holes 4411 are formed in the first core portion 441 of each of the U-phase stator core 44U, the V-phase stator core 44V, and the W-phase stator core 44W, and the U-phase stator core 44U and the V-phase stator core 44V are formed. A through hole 4421 is formed in the second core portion 442 of each of the W-phase stator core 44W and the W-phase stator core 44W. The through hole 4411 penetrates the first core portion 441 in the axial direction. The through hole 4421 penetrates the second core portion 442 in the axial direction.

In the example shown in FIGS. 7 and 8, each of the plurality of yoke portions 461 is connected to the end of the through hole 4411 on the back yoke 46 side so that the refrigerant flows in the through hole 4411, and the refrigerant flows. A second cooling space 4641 is formed, and the second cooling space 4642 is connected to the end of the through hole 4421 on the back yoke 46 side so that the refrigerant flows in the through hole 4421, and allows the refrigerant to flow. Is formed.

In such an embodiment, since the refrigerant flows inside the first core portion 441 and the second core portion 442, the first core portion 441 and the second core portion 442 can be directly cooled by the refrigerant.

Although the embodiments of the present invention have been described in detail above, these are merely examples, and the present invention is not to be interpreted in a limited manner by the description of the above-described embodiments.

For example, in the above embodiment, the motor which is an example of the axial gap type rotary electric machine has been described, but the axial gap type rotary electric machine may be a generator.

For example, in the above embodiment, the embodiment in which the axial gap type rotary electric machine includes two stators has been described, but the axial gap type rotary electric machine may have only one stator.

For example, in the modified example 3 of the above embodiment, the through hole is formed in each of the first core portion and the second core portion, but the through hole is formed only in either the first core portion or the second core portion. It may be formed.

10 Motor 30 Rotor 40 Stator 42U U-phase coil 42V V-phase coil 42W W-phase coil 421 1st coil part 422 2nd coil part 44U U-phase stator core 44V V-phase stator core 44W W-phase stator core 441 1st core part 4411 Communication hole 442 2 core part 4421 communication hole 46 back yoke 461 yoke part 462 connection part 463 first cooling space 464 second cooling space 47 cooling pipe

Claims (5)

Axial gap type rotary electric machine
With the rotor
It is provided with a stator which is arranged so as to face the rotor in the axial direction of the rotor and rotates the rotor by an electromagnetic force acting between the rotor and the rotor.
The stator is
A U-phase coil through which an alternating current for rotating the rotor flows, and
The U-phase stator core around which the U-phase coil is wound and
A V-phase coil that is arranged at a position different from the U-phase coil in the circumferential direction that is the rotation direction of the rotor and has an alternating current having a phase different from the alternating current flowing through the U-phase coil.
The V-phase stator core around which the V-phase coil is wound and
A W-phase coil that is arranged at a position different from the U-phase coil and the V-phase coil in the circumferential direction, and has an alternating current having a phase different from the alternating current flowing through the U-phase coil and the alternating current flowing through the V-phase coil. When,
The W-phase stator core around which the W-phase coil is wound and
Includes the U-phase coil, the V-phase coil, and a back yoke disposed axially away from the rotor than the W-phase coil.
Each of the U-phase stator core, the V-phase stator core, and the W-phase stator core
The first core part and
A second core portion arranged next to the first core portion in the circumferential direction and paired with the first core portion is included.
Each of the U-phase coil, the V-phase coil, and the W-phase coil
The first coil portion wound around the first core portion and
A second coil portion connected to one end of the first coil portion and wound around the second core portion in a direction opposite to the direction in which the first coil portion is wound around the first core portion is included. ,
The back yoke is
Includes a plurality of yokes arranged so as to be spaced apart from each other in the circumferential direction.
The plurality of yoke portions are generated by energization of the first coil portion of each of the U-phase coil, the V-phase coil, and the W-phase coil, and the magnetic flux passing through the first core portion is said. Each pair the first core portion and the first core portion when viewed from the axial direction so as to pass through the second core portion that forms a pair with the first core portion after flowing in the circumferential direction. It overlaps with the second core portion and extends in the circumferential direction while having a predetermined yoke portion thickness in the axial direction.
The back yoke has a first cooling space that allows a refrigerant for cooling the stator to flow in the radial direction of the rotor between two yoke portions adjacent to each other in the circumferential direction among the plurality of yoke portions. An axial gap type rotary electric machine in which the thickness in the axial direction is smaller than the thickness of the yoke portion between two yoke portions adjacent to each other in the circumferential direction so as to be formed. The axial gap type rotary electric machine according to claim 1.
An axial gap type rotary electric machine in which the plurality of yoke portions are separated from each other in the circumferential direction. The axial gap type rotary electric machine according to claim 1.
The back yoke is interposed between two adjacent yoke portions in the circumferential direction so as to allow the magnetic flux to flow between the two adjacent yoke portions in the circumferential direction. An axial gap type rotary electric machine, further including a connection portion for connecting the connection portion, wherein the thickness of the connection portion in the axial direction is smaller than the thickness of the yoke portion. The axial gap type rotary electric machine according to any one of claims 1 to 3.
An axial gap type rotary electric machine further provided with a plurality of cooling pipes arranged between two yoke portions adjacent to each other in the circumferential direction and allowing the refrigerant to flow into the first cooling space. The axial gap type rotary electric machine according to any one of claims 1 to 4.
At least one of the first core portion and the second core portion is formed with a through hole extending in the axial direction and penetrating the stator core.
A second cooling space is formed in each of the plurality of yoke portions, which is connected to the end of the through hole on the back yoke side so that the refrigerant flows in the through hole and allows the refrigerant to flow. An axial gap type rotary electric machine in which a portion having a thickness smaller than the thickness of the yoke portion is formed in the axial direction.

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