JP2023103617A - Rotary electric machine - Google Patents

Abstract

To improve the utilization efficiency of magnetic flux emitted from a magnet provided on a rotor.SOLUTION: A rotary electric machine includes an annular stator, and a rotor disposed radially inside the stator and facing the stator, the rotor includes a rotor core, and a magnet attached to the rotor core, and the stator includes a stator core having an extension projecting radially inward from a main body positioned around the rotor, where the magnet attached to the rotor core is positioned, and a coil attached to the stator core.SELECTED DRAWING: Figure 6

Description

The present invention relates to rotating electric machines.

2. Description of the Related Art Conventionally, a so-called radial gap type motor is known in which a stator and a rotor are arranged to face each other in the radial direction (see, for example, Patent Document 1). In Patent Document 1, in order to effectively utilize the magnetic flux of the magnets embedded inside the rotor, overhangs are formed at both ends of the stator core in the axial direction, and the axial length of the stator is made longer than the axial length of the rotor. An elongated motor (rotating electrical machine) is disclosed.

JP 2015-33244 A

By the way, in order to improve the output of the motor, it is effective to flow the magnetic flux emitted by the magnets to the stator side as much as possible. The overhang portion provided in the motor disclosed in Patent Document 1 can capture the magnetic flux emitted from the magnet and allow the captured magnetic flux to flow inside the stator. However, the magnetic flux emitted from the magnet is emitted in all directions. The motor disclosed in Patent Literature 1 has room for further improvement from the standpoint of capturing as much magnetic flux emitted in all directions as possible and improving the utilization efficiency of the magnetic flux.

Accordingly, an object of the invention disclosed in this specification is to improve the utilization efficiency of the magnetic flux emitted from the magnets provided on the rotor.

A rotating electric machine disclosed in the present specification is a rotating electric machine that includes an annular stator and a rotor that is arranged radially inside the stator so as to face the stator, wherein the rotor includes a rotor core and a magnets attached to the stator core, the stator having extensions projecting radially inwardly from a body portion positioned around the rotor at which the magnets attached to the rotor core are located; a coil mounted on the

The invention disclosed in this specification can improve the utilization efficiency of the magnetic flux emitted from the magnets provided on the rotor.

FIG. 1 is a plan view of the rotary electric machine of the first embodiment. FIG. 2 is a perspective view of a split stator forming a stator included in the rotary electric machine of the first embodiment. FIG. 3 is a plan view showing an enlarged part of the rotary electric machine of the first embodiment. FIG. 4 is a plan view of the split stator. FIG. 5 is a plan view showing part of the rotor. FIG. 6 is an explanatory view schematically showing a part of the axial cross section of the rotating electric machine of the first embodiment. FIG. 7 is an explanatory view schematically showing a part of an axial cross-section of a rotating electric machine of a modification. FIG. 8 is a plan view showing part of the rotor of the second embodiment. FIG. 9 is a plan view of the split stator of the third embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, in the drawings, the dimensions, ratios, etc. of each part may not be illustrated so as to completely match the actual ones. In some drawings, details may be omitted. Furthermore, the scale of each element drawn between each drawing may be different.

(First embodiment)
First, referring to FIG. 1, a schematic configuration of a rotating electrical machine 1 according to the first embodiment will be described. The rotary electric machine 1 is a three-phase AC motor having a U phase, a V phase and a W phase, and is used in hybrid vehicles, electric vehicles, fuel cell vehicles, etc., which are equipped with an engine and a driving motor as driving sources of the vehicle, for example. It is used as a travel motor for electric vehicles. Further, the rotating electrical machine 1 is a permanent magnet synchronous rotating electrical machine in which permanent magnets 8b are embedded inside a rotor core 8a, that is, a so-called IPM (Interior Permanent Magnet) motor, as will be described later in detail. The rotating electric machine may be not only an IPM motor but also an SPM (Surface Permanent Magnetic) motor. In the following description, "axial direction", "radial direction", and "circumferential direction" mean the axial direction of the rotor, the radial direction of the rotor, and the circumferential direction of the rotor, respectively.

The rotary electric machine 1 is provided in a case 2, and includes an annular stator 3 having teeth 6 formed with coil portions 7, and a rotor arranged radially inwardly of the stator 3 so as to be concentric with the stator 3 and opposed to the stator 3. 8. The stator 3 has a stator core 3 a and coils 7 . The rotor 8 includes a rotor core 8a and permanent magnets 8b embedded in the rotor core 8a. The rotor 8 is rotatably provided within the stator 3 . A rotary shaft member 9 is provided at the center of the rotor 8, and the rotary shaft member 9 is rotatably supported by a bearing (not shown). The rotating electric machine 1 has a U-phase lead wire, a V-phase lead wire, and a W-phase lead wire extending from the coil portion 7, but these lead wires are omitted in FIG.

The stator core 3a is formed by connecting the split stator cores 4 shown in FIGS. The stator core 3a is formed by combining 16 divided stator cores 4 in total. Each split stator core 4 has a fan shape with a central angle of θ. A central angle θ of one divided stator 4 in the rotary electric machine 1 of this embodiment is 45°. The stator core 3a has a configuration in which two annular bodies formed by connecting eight divided stators 4 in the circumferential direction are joined together while being turned upside down (see FIG. 6). The central angle θ of the stator core segments 4 and the number of stator core segments 4 are not limited to these. The central angle θ of the stator core segments 4 and the number of stator core segments 4 can be appropriately selected to form an annular shape.

As shown in FIG. 2, the split stator core 4 includes a block-shaped main body portion 4a and an upper layer portion 4b on one axial end side of the main body portion 4a.

The main body 4a is a powder magnetic core formed by compressing and molding magnetic powder coated with insulation, but it may be formed by stacking electromagnetic steel sheets. The upper layer portion 4b is provided by stacking a plate-like member on one end portion of the main body portion 4a. The upper layer portion 4b is provided by molding an electromagnetic steel plate. The main body portion 4a forms the main body portion 3a1 (see FIG. 6) of the stator core 3a when the stator core segments 4 are joined to form the stator core 3a. The body portion 3 a 1 is formed in an annular shape and positioned around the rotor 8 . The inner peripheral wall surface 4c of the split stator core 4 faces the outer peripheral wall surface 8a1 of the rotor 8 in the state where the stator core 3a is formed. A gap 10 (see FIG. 4) is formed between the inner peripheral wall surface 4c and the outer peripheral wall surface 8a1. This allows the rotor 8 to rotate inside the stator 3 . Further, referring to FIG. 6, the axial height of the main body portion 3a1 is set to be higher than the axial height of the rotor 8, and both ends of the main body portion 3a1 are higher than both ends of the rotor 8. is also in a prominent state.

The split stator core 4 has a yoke portion 5 on the radially outer side. The split stator core 4 includes tooth portions 6 extending radially inward from the yoke portion 5 . A groove-like slot is provided between each tooth portion 6 and is open radially inward and is open on both sides in the axial direction. A coil 7 is provided in the slot as shown in FIGS. Coils 7 are provided so as to straddle predetermined tooth portions 6 so as to form U-phase, V-phase and W-phase.

The upper layer portion 4b provided in the split stator core 4 forms part of the yoke portion 5 and the teeth portion 6 together with the main body portion 4a. The upper layer portion 4b includes extension portions 6a in which the tooth portions 6 protrude radially inward. The extended portion 6a will be described later in detail.

The rotor 8 comprises permanent magnets 8a. As shown in FIG. 6, the permanent magnets 8b are embedded in holes axially penetrating the rotor core 8a. As shown in FIG. 5 and the like, the permanent magnet 8b has a substantially rectangular outer shape when viewed in the axial direction, and is embedded with the longitudinal direction substantially aligned with the circumferential direction and the short side direction substantially aligned with the radial direction. is The permanent magnet 8b is magnetized along the short direction. Specifically, as shown in FIG. 6, the permanent magnet 8b is magnetized so that the radially outer side is the north pole and the radially inner side is the south pole.

Here, the extended portion 6a will be described in detail. Referring to FIGS. 2 and 6, the extended portion 6a is formed in the upper layer portion 4b. The extension portions 6a are formed by causing the teeth portions 6 to protrude radially inward. The tip of the extended portion 6a is located inside 4b of the inner peripheral wall surface 4c. As a result, the distal end of the extended portion 6a protrudes to the vicinity of the permanent magnet 8b embedded in the rotor 8. As shown in FIG. The extension portion 6a is formed in an upper layer portion 4b provided at one end portion of the main body portion 3a1 of the stator core 3a. The axial height of the main body portion 3 a 1 is higher than the axial height of the rotor 8 . For this reason, the extended portion 6 a is arranged in such a manner as to cover the rotor 8 .

As shown in FIG. 6, a slope 6a1 is formed at the tip of the extended portion 6a facing the rotor 8 so as to recede from the permanent magnet 8b as it approaches the center. By forming the inclined surface 6a1, the extended portion 6a is close to the N pole of the permanent magnet 8b and far from the S pole.

The extension 6a can capture the magnetic flux emitted from the north pole of the permanent magnet 8b. The permanent magnet 8b emits magnetic flux in all directions, that is, in the axial direction, radial direction, circumferential direction of the rotor 8, and combined directions thereof. Of the magnetic flux emitted by the permanent magnet 8b, the magnetic flux indicated by an arrow 20a flows toward the stator 3 through the rotor core 8a. Of the magnetic flux emitted by permanent magnet 8b, the magnetic flux emitted from the upper and lower surfaces of permanent magnet 8b as indicated by arrow 20b is captured by extending portion 6a from inclined surface 6a1. The magnetic flux captured by the extended portion 6a flows toward the stator 3 as indicated by an arrow 20c. The magnetic flux flowing to the stator 3 side contributes to the output of the rotating electric machine 1 . If the extended portion 6a were not provided, the magnetic flux as indicated by the arrow 20b would be released into space and would not contribute to the output of the rotary electric machine 1. FIG. By providing the extended portion 6 a as in the present embodiment, the magnetic flux emitted from the axial end face of the permanent magnet 8 b can be captured and contributed to the output of the rotary electric machine 1 .

Here, the inward projection amount and shape of the extended portion 6a will be considered while comparing with the modified example shown in FIG. The modified example shown in FIG. 7 is also included in the scope of the invention disclosed in this specification. Conventionally, the magnetic flux released into the space can be captured, and the magnetic flux can contribute to the output of the rotating electric machine 1. be able to. In FIG. 7, the same reference numerals are given to the components common to the first embodiment. The modification shown in FIG. 7 includes a stator 13 (stator core 13a) instead of the stator 3 (stator core 3a) provided in the first embodiment shown in FIG. The stator core 13a includes a body portion 13a1 and an upper layer portion 41b. The main body portion 13a1 is common to the first embodiment in that the inner peripheral wall surface 14c faces the outer peripheral surface 8a1 of the rotor 8a in the radial direction and that the tooth portions 16 are provided. It differs from the embodiment. An extending portion 16a is provided in the upper layer portion 14b, and the tip of the extending portion 16a reaches further inside beyond the S pole of the permanent magnet 8b. Further, unlike the extension portion 6a, the distal end portion of the extension portion 16a does not have an inclined surface. The inclined surface 6a1 is provided to face the extension 6a to the N pole of the permanent magnet 8b. The installation portion 16a passes over the N pole. Therefore, since the extended portion 16a faces the N pole on its lower surface, no inclined surface is required.

The extending portion 16a can flow magnetic flux to the stator 13 as indicated by arrows 21a, 21b, and 21c in FIG. 7, similarly to the extending portion 6a of the first embodiment. However, on the other hand, as indicated by arrow 21b, the magnetic flux captured by extension 16a flows further toward the distal end of extension 16a, as indicated by arrow 21d. The magnetic flux that has flowed to the tip side of the extended portion 16a returns to the S pole of the permanent magnet 8b as indicated by an arrow 21e. Thus, the magnetic flux that returns to the S pole of the permanent magnet 8b does not contribute to the output of the rotary electric machine 1.

Therefore, it is desirable to set the amount of protrusion and the shape of the extended portion so that the magnetic flux emitted by the permanent magnet 8b efficiently flows to the stator side. In other words, it is desirable that the projection amount and shape of the extended portion be set so as not to cause a phenomenon in which the once captured magnetic flux returns to the permanent magnet 8b without flowing to the stator 3 side. The extension protrudes inward so as to cover the rotor 8 side, but the amount and shape of the protrusion can be changed in various ways according to the positional relationship with the permanent magnets.

The relative positional relationship between the permanent magnet and the extended portion and the relative attitude of the permanent magnet to the extended portion change every moment. These matters should be taken into consideration when determining the projection amount and shape of the extended portion. The rotor 8 in which the permanent magnets 8b are embedded rotates with respect to the stator 3 (13). Therefore, the relative positional relationship and relative posture between the permanent magnet 9b and the extension portion 6a (16a) change. At some times the extension is close to the north pole and can effectively trap the magnetic flux, but at other times it is close to the south pole and is shown by arrow 21e in FIG. The magnetic flux returned to the pole increases. As described above, the relationship between the extension portion and the permanent magnet 8b changes from moment to moment, so that the amount and shape of protrusion of the extension portion can efficiently improve the output of the rotary electric machine 1 for a certain period of time. It should be set so that As a basic idea, if the extended portion is far from the S pole and close to the N pole, it can efficiently capture the magnetic flux and contribute the magnetic flux to the output of the rotating electric machine 1 .

The rotary electric machine 1 of the present embodiment includes the upper layer portion 4b at the axial end portion of the stator core 3a. As shown in FIG. placed in between. A gap 11 is originally formed between the stator core 3 a and the coil 7 . The uppermost layer 4 b is arranged in this gap 11 . Therefore, even if the rotating electrical machine 1 is provided with the uppermost layer 4b, the size of the frame of the rotating electrical machine 1 as a whole does not increase. That is, an increase in the distance between the coil end portions formed at both ends in the axial direction is avoided.

Moreover, the volume of the stator 3 as a whole is increased by providing the uppermost layer 4b and providing the extended portion 6a. Thereby, the magnetic flux emitted from the coil and the magnetic flux emitted from the permanent magnet 8b can be efficiently captured. As a result, the output of the rotary electric machine 1 can be improved.

In this embodiment, the uppermost layer 4b is provided on both ends in the axial direction (vertical direction) as shown in FIG. In that case, considering the manufacturing process, it is possible to select a mode in which only one of the uppermost layers 4b is provided. In the present embodiment, a powder magnetic core is used. However, when a powder magnetic core is used, it may be complicated to provide the upper layer portions 4b on both sides in consideration of the entire assembly process. In such a case, the upper layer portion 4b may be provided on only one of them.

According to the rotating electric machine of the present embodiment, the stator core 3a includes the extending portion 6a projecting inward in the radial direction where the permanent magnet 8b is positioned. Efficiency can be improved.

(Second embodiment)
A second embodiment will now be described with reference to FIG. The second embodiment has a rotor 18 instead of the rotor 8 of the first embodiment. The rotor 18 includes outer permanent magnets 18b1 and inner permanent magnets 18b2 in a rotor core 18a. The inner permanent magnet 18b2 is arranged inside the outer permanent magnet 18b1. The outer permanent magnets 18b1 are provided on both sides of the outer permanent magnets 18b1. One outer permanent magnet 18b1 and two inner permanent magnets 18b2 form a set and are provided along the circumferential direction of the rotor 18 at predetermined intervals. In this embodiment, a set of an outer permanent magnet 18b1 and an inner permanent magnet 18b2 is provided every 45 degrees. In the drawings, the same reference numerals are used for common components in the first embodiment and the second embodiment.

In the second embodiment, such a rotor 18 is combined with the stator 3 . The stator 3 is the same as that of the first embodiment, and the split stator core 4 forming the stator 3 is provided with an extension portion 6a. The extending portion 6a protrudes toward the outer permanent magnet 18b1 and the inner permanent magnet 18b2. Therefore, the magnetic flux emitted from the outer permanent magnet 18b1 and the inner permanent magnet 18b2 can be effectively captured, and the captured magnetic flux can contribute to the output of the rotating electric machine 1.

As described in the first embodiment, it is desirable to set the amount of protrusion and the shape of the extended portion so that the magnetic flux emitted by the permanent magnet 8b efficiently flows to the stator side. In this embodiment, the outer permanent magnets 18b1 and the inner permanent magnets 18b2 are different in distance and orientation with respect to the extending portion 6a. For this reason, it is desirable to set the projection amount and shape of the extended portion that can effectively capture the magnetic flux in consideration of the arrangement of the outer permanent magnet 18b1 and the inner permanent magnet 18b2. For example, it is conceivable to set the magnetic flux to be effectively captured from the outer permanent magnet 18b1, or to set the magnetic flux to be effectively captured from both the outer permanent magnet 18b1 and the inner permanent magnet 18b2. can be selected.

The arrangement of permanent magnets may be changed in various ways. Therefore, it is desirable to appropriately select the amount of projection and the shape of the extension part in consideration of the arrangement of the permanent magnets.

(Third embodiment)
Next, a third embodiment will be described with reference to FIG. In the third embodiment, a split stator core 24 is employed instead of the split stator core 4 in the first embodiment. The stator core segments 24 have teeth portions 26 in the same manner as the stator core segments 4 of the first embodiment, but extension portions extending from the tooth portions 26 are different from those of the first embodiment. The extension part in this embodiment includes a first extension part 26a and a second extension part 26b. The first extension portion 26a and the second extension portion 26b have different inward projection amounts, and the projection amount of the first extension portion 26a is larger than the projection amount of the second extension portion 26b. The first extending portions 26a and the second extending portions 26b are provided alternately in the circumferential direction.

In this way, by varying the amount of protrusion of the extensions, it is possible to accommodate changes in the relative positional relationship and attitude with respect to the extensions due to the arrangement of the permanent magnets and the rotation of the rotor. For example, even if the position of the permanent magnet 8b moves as indicated by the arrow 27, the extension part is set so that the magnetic flux can be effectively captured with respect to the position and attitude at each point in time. The amount of projection of the first extension portion 26a and the second extension portion 26b can be appropriately selected from such a viewpoint.

By providing the extension portions with different protrusion amounts, it is possible to improve the utilization efficiency of the magnetic flux emitted from the permanent magnets and improve the output of the rotary electric machine.

The above-described embodiments are merely examples for carrying out the present invention, and the present invention is not limited to these. Various modifications of these examples are within the scope of the present invention, and furthermore, the present invention can be modified. It is self-evident from the above description that many other embodiments are possible within the scope.

1 rotating electric machine 2 case 3, 13 stator 3a, 13a stator core 3a1 body portion 4, 24 divided stator cores 4a, 14a body portion 4b, 14b upper layer portion 4c, 14c inner peripheral wall surface 5 yoke portion 6, 16 tooth portion 6a, 16a extension Part 6a1 Slope 7 Coil 8, 18 Rotor 8a Rotor core 8a1 Outer peripheral wall surface 8b Permanent magnet 9 Rotating shaft member 10 Gap 18b1 Outer permanent magnet 18b2 Inner permanent magnet 26a First extension 26b Second extension

Claims (1)

A rotating electric machine comprising a ring-shaped stator and a rotor disposed facing the stator radially inside the stator,
the rotor comprises a rotor core and magnets attached to the rotor core;
The stator includes a stator core having an extension portion radially inwardly projecting from a body portion positioned around the rotor, where the magnets attached to the rotor core are located, and a coil mounted on the stator core. rice field,
rotating electric machine.

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