WO2019064746A1

WO2019064746A1 - Rotor and motor comprising rotor

Info

Publication number: WO2019064746A1
Application number: PCT/JP2018/023719
Authority: WO
Inventors: 古舘　栄次; 香織宮田
Original assignee: 日本電産株式会社
Priority date: 2017-09-27
Filing date: 2018-06-22
Publication date: 2019-04-04

Abstract

A rotor that comprises: a rotor core that is arranged along a vertical center axis; and a plurality of magnets that are arranged on the rotor core side-by-side in the circumferential direction. The rotor core has a plurality of magnet housing parts that are arranged side-by-side in the circumferential direction and house at least parts of the magnets. The magnet housing parts extend from the center axis side toward the radial direction outside, and recesses that are recessed from an outer circumferential surface of the rotor core toward the radial direction inside are provided at the radial direction outside of the magnet housing parts. At least parts of pressing members that directly or indirectly press the magnets toward the radial direction inside are arranged in the recesses.

Description

Rotor and motor provided with the rotor

The present invention relates to a rotor and a motor provided with the rotor.

The rotor in the conventional electric motor includes a rotor core provided on a rotating shaft, a plurality of magnet insertion holes formed circumferentially in the rotor core, a permanent magnet inserted and embedded in the magnet insertion hole, and a magnet insertion on the surface of the permanent magnet And a resin member that covers an outer peripheral surface facing the inner peripheral surface of the hole (e.g., Patent Document 1).

On one side of the radially inner peripheral surface of the magnet insertion hole, a protrusion for preventing the permanent magnet from falling is formed. A permanent magnet on which a coating of a resin member is formed is pressed into and fixed to the magnet insertion hole.

JP, 2013-219948, A

However, according to the above-mentioned conventional rotor, before the press-fitting of the magnet into the magnet insertion hole, the magnet is coated with the resin member in advance and the projection is arranged in advance in the magnet insertion hole. For this reason, variation may occur in the thickness of the resin member or the protrusion amount of the protrusion. In this case, if the thickness of the resin member or the amount of protrusion of the protrusion is insufficient, there is a problem that rattling of the magnet accommodated in the magnet insertion hole occurs. On the other hand, when the thickness of the resin member or the protrusion amount of the protrusion is increased, it takes time and effort to press the magnet into the magnet insertion hole, which causes problems such as breakage of the magnet and an increase in the number of manufacturing steps.

An embodiment of the present invention provides a rotor that can suppress an increase in the number of manufacturing steps while suppressing rattling of the magnet in the magnet housing portion, and a motor including the rotor.

An exemplary rotor of the present invention comprises a rotor core disposed along a vertically extending central axis, and a plurality of magnets circumferentially arranged on the rotor core, wherein the rotor core is at least one of the magnets. The magnet housing includes a plurality of magnet housings that are partially housed and arranged in the circumferential direction, and the magnet housing extends radially outward from the central axis side, and is radially outward of the magnet housing. Is provided with a recess which is recessed radially inward from the outer peripheral surface of the rotor core, and at least a part of a pressing member for pressing the magnet radially inward directly or indirectly is disposed in the recess .

An exemplary motor of the present invention comprises the rotor of the above configuration and a stator.

According to the exemplary rotor and motor of the present invention, it is possible to suppress the increase in the number of manufacturing processes while suppressing the rattling of the magnet in the magnet housing portion.

FIG. 1 is a plan view of a motor provided with a rotor according to an embodiment of the present invention. FIG. 2 is a perspective view showing a state in which a shaft of a rotor according to an embodiment of the present invention is attached. FIG. 3 is a plan view showing a state in which a shaft of a rotor according to an embodiment of the present invention is attached. FIG. 4 is a plan view showing a state before the pressing member of the rotor according to an embodiment of the present invention is disposed in the recess. FIG. 5 is a view on arrow A of FIG. FIG. 6 is a perspective view of a pressing member of a rotor according to an embodiment of the present invention. FIG. 7 is a plan view of a pressing member of a rotor according to an embodiment of the present invention. FIG. 8 is a perspective view showing a state in which a shaft of a rotor according to a first modification of the embodiment of the present invention is attached. FIG. 9 is a side view showing a state in which a shaft of a rotor according to a second modification of the embodiment of the present invention is attached. FIG. 10 is a perspective view showing a state in which a shaft of a rotor according to a third modification of the embodiment of the present invention is attached. FIG. 11 is a perspective view showing a state in which a shaft of a rotor according to a fourth modified example of the embodiment of the present invention is attached. FIG. 12 is a plan view showing a state in which a shaft of a rotor according to a fifth modification of the embodiment of the present invention is attached. FIG. 13 is an enlarged plan view of a part of the peripheral portion of a rotor according to a sixth modification of the embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. In the present specification, the direction in which the central axis of the motor extends is simply referred to as “axial direction”, and the direction orthogonal to the central axis (direction perpendicular to the axial direction) centered on the central axis of the motor is simply referred to as “radial direction”. A direction along an arc centering on the central axis of the motor is simply referred to as "circumferential direction". The central axis of the rotor core coincides with the central axis of the motor. Further, in the present specification, for convenience of explanation, the shape and positional relationship of each part will be described with the axial direction as the vertical direction and the direction orthogonal to the sheet of FIG. 1 as the rotor core, the rotor and the motor. Note that the definition in the vertical direction does not limit the direction of use of the motor. Also, as used herein, "parallel" and "perpendicular" include near parallel and near vertical as well as parallel and vertical in the strict sense respectively.

<1. Overall configuration of motor>

An overall configuration of a motor according to an exemplary embodiment of the present invention will be described. FIG. 1 is a plan view of a motor according to an embodiment of the present invention. The motor 1 is a so-called inner rotor type motor and has a stator 2 and a rotor 3. The motor 1 further has a cylindrical housing (not shown) that encloses the stator 2 and the rotor 3. The stator 2 is fixed to the housing by, for example, press fitting or shrink fitting. The motor 1 may further include a control board (not shown) connected to the stator 2.

The stator 2 has, for example, an axially extending cylindrical shape. The stator 2 is disposed radially outside the rotor 3 with a predetermined gap. The stator 2 has a stator core 21, an insulator 22, and a coil 23.

The stator core 21 has a cylindrical shape extending in the axial direction. The stator core 21 is formed by laminating a plurality of electromagnetic steel plates in the axial direction. The stator core 21 may be a dust core. The stator core 21 has a core back 21 a and a plurality of teeth (not shown). The core back 21a has an annular shape. The teeth extend radially inward from the inner peripheral surface of the core back 21a. The plurality of teeth are arranged in the circumferential direction at predetermined intervals. In the present embodiment, the number of teeth is twelve. The number of teeth is not particularly limited, and may be arbitrarily changed in accordance with a desired specification. Further, in the present embodiment, the stator core 21 is a so-called round core. The stator core 21 may be a split core or a straight core formed by connecting a plurality of T-shaped core back pieces having teeth in a strip shape.

The insulator 22 covers the outer surface of the teeth. The insulator 22 is disposed between the stator core 21 and the coil 23. The insulator 22 is made of, for example, an insulating material such as a synthetic resin. The coil 23 is configured by winding a conducting wire around the teeth via the insulator 22.

<1-1. Rotor configuration>

FIG. 2 is a perspective view of the rotor 3 to which the shaft 4 is attached. FIG. 3 is a plan view of the rotor 3 to which the shaft 4 is attached. FIG. 4 is a plan view showing a state before the pressing member 34 of the rotor 3 to which the shaft 4 is attached is disposed in the recess 33. As shown in FIG.

The rotor 3 has an axially extending cylindrical shape. The rotor 3 is disposed radially inward of the stator 2 with a predetermined gap. The rotor 3 is an IPM (Interior Permanent Magnet) type rotor, and includes a rotor core 30 and a plurality of magnets 31.

The rotor core 30 is disposed along a central axis C extending up and down and has an electromagnetic steel plate 30b. The electromagnetic steel plate 30 b extends radially outward with respect to the central axis C of the rotor core 30. The rotor core 30 is a laminated steel plate in which a plurality of electromagnetic steel plates 30 b are laminated in the axial direction. The plurality of electromagnetic steel plates 30b are fixed to each other by, for example, caulking or welding. The rotor core 30 is not limited to a laminated steel plate, and may be, for example, a dust core.

In the present embodiment, the rotor core 30 has a substantially cylindrical shape extending in the axial direction. A hole 30 a penetrating in the axial direction is disposed at the center of the rotor core 30. A portion of the shaft 4 is press-fitted into the hole 30a. The shaft 4 is a rotating shaft of the motor 1. In the present embodiment, the shaft 4 has a cylindrical shape extending in the vertical direction. The shaft 4 may be a hollow member. In addition, a member such as a resin member or a metal member may be attached in the hole 30a, and a part of the shaft 4 may be fixed to the hole 30a via the member. That is, the shaft 4 is fixed to the rotor core 30 directly or indirectly.

The upper end side and the lower end side of the shaft 4 are rotatably supported by upper and lower bearings (both not shown) provided above and below the rotor 3. Thus, the rotor 3 can rotate around the central axis C together with the shaft 4 extending in the vertical direction. In the present embodiment, the central axis of the rotor core 30 coincides with the shaft 4 of the motor 1. Note that only one of the upper end and the lower end of the shaft 4 may be rotatably supported by the bearing. The bearing may be a ball bearing or the like, and the type is not particularly limited.

The rotor core 30 has a plurality of magnetic pole portions 35 and a plurality of magnet housing portions 32. The plurality of magnetic pole portions 35 are arranged at substantially equal intervals in the circumferential direction. The shape of each magnetic pole portion 35 is substantially fan-shaped as viewed from the axial direction. The radially outer end surface of the magnetic pole portion 35 radially faces the radially inner end surface of the teeth of the stator core 21.

The magnet housing portion 32 is a through hole which penetrates the rotor core 30 in the axial direction. The plurality of magnet housing portions 32 are arranged side by side in the circumferential direction, and extend radially outward from the central axis C side. Each magnet housing portion 32 is disposed between the magnetic pole portions 35 adjacent in the circumferential direction. In the present embodiment, the shape of the cross section perpendicular to the axial direction of the magnet housing portion 32 is a rectangular shape extending in the radial direction. The inner wall 32 a of the magnet housing portion 32 is disposed on both sides in the circumferential direction and both sides in the radial direction of the magnet housing portion 32.

Each magnet housing portion 32 houses at least a part of the magnet 31. The plurality of magnets 31 are arranged in the circumferential direction on the rotor core 30. That is, the rotor 3 is a so-called spoke-type rotor in which a plurality of magnets 31 are arranged radially. In the present embodiment, the shape of the cross section perpendicular to the axial direction of the magnet 31 is a rectangular shape extending in the radial direction. In other words, in the present embodiment, the shape of the magnet 31 is a plate extending in the radial direction. In the present embodiment, eight magnet housing portions 32 and eight magnets 31 are provided. The axial length of the magnet 31 substantially coincides with the axial length of the magnet housing portion 32.

The circumferential end surface of the magnet 31 is a magnetic pole surface that faces the circumferential end surface of the magnetic pole portion 35 in the circumferential direction. The plurality of magnets 31 are arranged such that the magnetic pole faces of the same pole face each other in the circumferential direction. The magnetic pole portion 35 is magnetized by magnets 31 disposed on both sides in the circumferential direction of the magnetic pole portion 35. Thus, the radially outer end surface of the magnetic pole portion 35 becomes a magnetic pole surface.

The axial length of the magnet 31 may be shorter than the axial length of the magnet housing portion 32. The number of magnet housing portions 32 and the number of magnets 31 are not particularly limited, and may be arbitrarily changed in accordance with desired specifications. The shape of the magnet 31 is not limited to the above-described shape. The shape of the magnet 31 may be any shape as long as it can be housed in the magnet housing portion 32, and may be a shape in which the circumferential end surface is a curved surface, and is not particularly limited. Further, the type of the magnet 31 may be a neodymium sintered magnet, a neodymium bond magnet, a ferrite magnet or the like, and is not particularly limited.

A recess 33 that is recessed radially inward from the outer peripheral surface of the rotor core 30 is provided radially outward of the magnet housing portion 32. The recess 33 faces the magnet housing portion 32 in the radial direction. The recess 33 extends from one axial end of the rotor core 30 to the other axial end. In the case where the rotor core 30 has the recess 33, it is desirable that the position of the magnet 31 in the radial direction be closer to the outer peripheral side (i.e., the radial outer side) of the rotor core 30. In other words, the position of the magnet 31 is preferably closer to the radial outer opening of the recess 33. Thereby, magnetic flux can be smoothly flowed between the stator 2 and the rotor 3.

As shown in FIG. 4, the recess 33 has a narrow portion 331, an inner wide portion 332, and an outer wide portion 333. An inner wide portion 332, a narrow portion 331, and an outer wide portion 333 are arranged in order from the inner side in the radial direction to the outer side in the radial direction. The inner wide portion 332, the narrow portion 331, and the outer wide portion 333 communicate with each other in the radial direction. When viewed from the axial direction, the shape of the opening of the inner wide portion 332 is substantially C-shaped. When viewed from the axial direction, the narrow portions 331 are a pair of linear shapes extending in the radial direction from the inner wide portion 332. When viewed from the axial direction, the circumferential width of the outer wide portion 333 generally increases toward the radially outer side.

The longest width W2 in the circumferential direction of the inner wide portion 332 is larger than the width W1 in the circumferential direction of the narrow portion 331, and the shortest width W3 in the circumferential direction of the outer wide portion 333 is at least the circumferential width W1 of the narrow portion 331 is there. That is, the inner wide portion 332 is disposed radially inward of the narrow portion 331, and the width in the circumferential direction is larger than that of the narrow portion 331. The outer wide portion 333 is disposed radially outward of the narrow portion 331 and has a circumferential width greater than that of the narrow portion 331.

FIG. 5 is a view on arrow A of FIG. That is, it is the figure which looked at the magnet accommodating part 32 side in the recessed part 33 from the radial direction outer side. Hatching shows the magnet 31 in the figure. The inner wall of the recess 33 has a bridge portion 36 connected to the inner wall 32 a of the magnet housing portion 32.

The rotor core 30 in the present embodiment is configured by alternately laminating an electromagnetic steel plate 30 b having a bridge portion 36 and an electromagnetic steel plate 30 b having no bridge portion 36 in the axial direction. Therefore, the space portion 37 is formed between the bridge portions 36 adjacent in the axial direction. The electromagnetic steel plates 30 b having the bridge portions 36 and the electromagnetic steel plates 30 b not having the bridge portions 36 need not necessarily be alternately arranged. The rotor core 30 may have at least one or more electromagnetic steel plates 30 b having no bridge portion 36. The rotor core 30 may not include the electromagnetic steel plate 30 b having no bridge portion 36, and may be configured only of the electromagnetic steel plate having the bridge portion 36. In this case, the rotor core 30 does not have the space 37.

FIG. 6 is a perspective view of the pressing member 34. FIG. FIG. 7 is a plan view of the pressing member 34. FIG. The pressing member 34 has a first reinforcing portion 343 and a plurality of first extending portions 341. At least a part of the first extending portion 341 is disposed in the recess 33. The pressing member 34 is preferably made of, for example, a nonmagnetic material such as resin, nonmagnetic stainless steel, or aluminum. Although eight first extending portions 341 are arranged in the present embodiment, the number of first extending portions 341 is not limited thereto. That is, the number of first extending portions 341 may be equal to or less than the number of recesses 33.

The first reinforcing portion 343 is annular, and is located on the axially lower side (axially one side) of the rotor core 30. The first extending portion 341 extends axially upward from the first reinforcing portion 343 (the other side in the axial direction). In the present embodiment, the axial length of the first extending portion 341 is approximately half of the axial length of the rotor core 30, but may be the same as the axial length of the rotor core 30. The first reinforcing portion 343 connects the plurality of first extending portions 341. In the present embodiment, the first extending portion 341 is a member integral with the first reinforcing portion 343. The first extending portion 341 may be a member separate from the first reinforcing portion 343. In this case, it is desirable that the first reinforcing portion 343 be connected to the plurality of first extending portions 341 by, for example, welding or welding.

The cross-sectional shape perpendicular to the axial direction of the first extending portion 341 is substantially the same as the cross-sectional shape perpendicular to the axial direction of the recess 33. Moreover, in the state before inserting the first extending portion 341 into the recess 33, the area of the cross section perpendicular to the axial direction of the first extending portion 341 is larger than the area of the cross section perpendicular to the axial direction of the recess 33. There is.

<1-2. Mounting method of magnet and pressing member>

Next, a method of attaching the magnet 31 and the pressing member 34 to the rotor core 30 will be described. The magnet 31 is inserted into the magnet housing portion 32 in the axial direction. In the rotor core 30 before the pressing member 34 is disposed in the recess 33, the radial length of the magnet housing portion 32 is larger than the radial length of the magnet 31, and the circumferential length of the magnet housing portion 32 is Greater than the circumferential length. Therefore, when the magnet 31 is inserted into the magnet housing portion 32 in the axial direction, excessive stress is not applied to the magnet 31 from the electromagnetic steel plate 30 b. Therefore, the magnet 31 can be easily housed in the magnet housing portion 32. Further, when the magnet 31 is housed in the magnet housing portion 32, damage such as cracking of the magnet 31 can be prevented.

After the magnet 31 is housed in the magnet housing portion 32, the first extending portion 341 is inserted into the recess 33 in the axial direction. Thus, the first extending portion 341 is disposed in the recess 33. At this time, at least a part of the first extending portion 341 may be accommodated in the recess 33. Further, the upper surface (the surface on the other side in the axial direction) of the first reinforcing portion 343 contacts the lower surface (the surface on the one side in the axial direction) of the rotor core 30. The first reinforcing portion 343 covers at least a part of the opening at the lower end of the magnet housing portion 32. As a result, even when an impact or the like is applied to the rotor core 30 from the outside, the magnet 31 is prevented from coming out of the magnet housing portion 32. The first reinforcing portion 343 may not necessarily cover the opening at the lower end of the magnet housing portion 32.

Before the first extending portion 341 is disposed in the recess 33, the area of the cross section perpendicular to the axial direction of the first extending portion 341 is larger than the area of the cross section perpendicular to the axial direction of the recess 33 . Therefore, when the first extending portion 341 is disposed in the recess 33, the radially inner end portion of the first extending portion 341 presses the bridge portion 36 radially inward, so that the bridge portion 36 is elastically deformed. Then, the first extending portion 341 presses the magnet 31 radially inward via the bridge portion 36. That is, the pressing member 34 in the recess 33 indirectly presses the magnet 31 radially inward.

Thus, in the magnet housing portion 32, a radial gap between the inner wall 32a on the inner peripheral side of the magnet housing portion 32 and the magnet 31, and a radial gap between the inner wall 32a on the outer peripheral side of the magnet housing portion 32 and the magnet 31. Can be reduced. Further, when the magnet 31 is housed in the magnet housing portion 32, excessive stress is not received from the inner wall 32a of the magnet housing portion 32. For this reason, accommodation of the magnet 31 in the magnet accommodation part 32 can be performed smoothly. Therefore, it is possible to suppress an increase in the number of manufacturing steps of the rotor 3 and the motor 1 while suppressing the rattling of the magnet 31 housed in the magnet housing portion 32.

The first extending portion 341 can be reinforced by the first reinforcing portion 343. Moreover, the workability at the time of insertion to the recessed part 33 of several 1st extending | stretching part 341 can be improved by the 1st reinforcement part 343. FIG.

The circumferential width L1 (see FIG. 7) of the first extending portion 341 (the pressing member 34) in the inner wide portion 332 is larger than the narrow portion 331, and the circumferential maximum width W2 of the inner wide portion 332 (see FIG. 4) Less than see). Thereby, the radial narrowing of the pressing member 34 can be prevented by the narrow portion 331, and rattling of the magnet 31 can be further suppressed.

<2. Motor operation>

In the motor 1 configured as described above, when electric power is supplied to the coil 23 from an external power supply (not shown) via a control board or the like, magnetic flux in the radial direction is generated in the plurality of teeth of the stator core 21. At this time, the magnetic flux generated from the magnet 31 extends radially outward of the magnetic pole portion 35 through the magnetic pole portion 35. The interaction between the magnetic flux generated in the stator 2 and the magnetic flux of the magnet 31 generates torque in the circumferential direction. Thereby, the rotor 3 rotates around the central axis C with respect to the stator 2.

At this time, as described above, in the magnet housing portion 32, the gap in the radial direction between the inner wall 32a on the inner peripheral side of the magnet housing portion 32 and the magnet 31 and the inner wall on the outer peripheral side of the magnet housing portion 32 The gap in the radial direction between 32 a and the magnet 31 can be reduced. Therefore, the magnetic resistance of the motor 1 in the magnet housing portion 32 is reduced, and the magnetic flux flows smoothly between the stator 2 and the rotor 3. Therefore, the rotation efficiency of the motor 1 can be improved.

When the pressing member 34 is a nonmagnetic material, the leakage of the magnetic flux from the stator 2 to the pressing member 34 is suppressed, and the decrease in the rotation efficiency of the motor 1 is suppressed. In the magnet housing portion 32, an adhesive, a resin material, or the like may be further disposed. Thus, in the magnet housing portion 32, a radial gap between the inner wall 32a on the inner peripheral side of the magnet housing portion 32 and the magnet 31, and a radial gap between the inner wall 32a on the outer peripheral side of the magnet housing portion 32 and the magnet 31. Can be further reduced, and rattling of the magnet 31 housed in the magnet housing portion 32 can be further suppressed.

<3. First Modified Example>

FIG. 8 is a perspective view showing a state in which the shaft 4 of the rotor 3 of the first modified example of the present embodiment is attached. In addition, in FIG. 8, the mode in the middle of inserting the 2nd extending part 342 of the press member 34 in the recessed part 33 is shown.

The pressing member 34 has a second reinforcing portion 344 and a plurality of second extending portions 342 in addition to the first reinforcing portion 343 and the first extending portion 341. The second reinforcing portion 344 is annular, and is located on the other axial side (axially upper side) of the rotor core 30. The second extending portion 342 extends from the second reinforcing portion 344 in the axial direction to one side (axially lower side), and at least a part of the second extending portion 342 is accommodated in the recess 33. The second reinforcing portion 344 connects the plurality of second extending portions 342. In the present modification, the second reinforcing portion 344 is integrally formed with the second extending portion 342. The second reinforcing portion 344 may be configured separately from the second extending portion 342. In this case, it is desirable that the second reinforcing portion 344 be connected to the plurality of second extending portions 342 by, for example, welding or welding. Although the number of second extending portions 342 is eight in the present embodiment, the present invention is not limited to this. That is, the number of second extending portions 342 may be equal to or less than the number of concave portions 33. Further, in the present embodiment, the number of first extending portions 341 is the same as the number of second extending portions 342. The number of first extending portions 341 may be different from the number of second extending portions 342.

The second reinforcing portion 344 is configured in the same manner as the first reinforcing portion 343. The shape of the second reinforcing portion 344 does not have to be the same as the shape of the first reinforcing portion 343 and may be different from each other. The second extending portion 342 is configured in the same manner as the first extending portion 341. The shape of the second extending portion 342 does not have to be the same as the shape of the first extending portion 341, and may be different from each other. Further, the axial length of the first extending portion 341 and the axial length of the second extending portion 342 are substantially the same, and are approximately half of the axial length of the rotor core 30. The axial length of the first extending portion 341 does not have to be the same as the axial length of the second extending portion 342, and the lengths may be different from each other. The axial length of the first extending portion 341 may be longer than the axial length of the second extending portion 342, or the axial length of the second extending portion 342 is greater than the axial length of the first extending portion 341 It may also be long. Even in this case, it is desirable that the sum of the axial length of the first extending portion 341 and the axial length of the second extending portion 342 be the axial length of the rotor core 30.

The tip of the first extending portion 341 on the upper side in the axial direction (the other side in the axial direction) contacts or opposes the tip on the lower side (the one side in the axial direction) of the second extending portion 342 in the axial direction. Similar to the first extending portion 341, the second extending portion 342 presses the magnet 31 radially inward via the bridge portion 36. Thus, in the magnet housing portion 32, a radial gap between the inner wall 32a on the inner peripheral side of the magnet housing portion 32 and the magnet 31, and a radial gap between the inner wall 32a on the outer peripheral side of the magnet housing portion 32 and the magnet 31. Can be reduced. Therefore, rattling of the magnet 31 housed in the magnet housing portion 32 can be suppressed. In addition, the second extending portion 342 can be reinforced by the second reinforcing portion 344, and the workability at the time of insertion of the plurality of second extending portions 342 into the recess 33 can be improved.

<4. Second Modified Example>

FIG. 9 is a perspective view showing a state in which the shaft 4 of the rotor 3 of the second modified example of the present embodiment is attached. As shown in FIG. 9, the rotor core 30 may be divided into a plurality of stages in the axial direction. More preferably, the rotor core 30 has a skew structure axially divided into a plurality of stages. The rotor core 30 includes, for example, a first rotor core 301 and a second rotor core 302. The first rotor core 301 and the second rotor core 302 are configured by laminating a plurality of electromagnetic steel plates 30 b in the axial direction, as in the above-described embodiment. The second rotor core 302 is located on the axially upper side (the other axial side) of the first rotor core 301. Each of the first rotor core 301 and the second rotor core 302 has the recess 33, the bridge portion 36, the magnet housing portion 32, and the magnet 31 as in the above-described embodiment. The axial height of the first rotor core 301 is the same as the axial height of the second rotor core 302. The axial height of the first rotor core 301 may be different from the axial height of the second rotor core 302. Furthermore, the first rotor core 301 is arranged to be offset from the second rotor core 302 by a predetermined angle in the circumferential direction around the central axis C. The rotor core 30 may be axially divided into three or more stages instead of two stages.

The first reinforcing portion 343 is disposed on one side in the axial direction of the first rotor core 301. The first reinforcing portion 343 axially faces or contacts the surface on one axial side of the first rotor core 301. More preferably, the first reinforcing portion 343 covers at least a part of the opening at the lower end of the magnet housing portion 32 of the first rotor core 301. As a result, in the first rotor core 301, the magnet 31 is prevented from coming off the magnet housing portion 32 in the axial direction. At least a portion of the first extending portion 341 is accommodated in the recess 33 of the first rotor core 301. Thereby, in the first rotor core 301, the first extending portion 341 can press the bridge portion 36, and rattling of the magnet 31 housed in the magnet housing portion 32 can be suppressed.

Similarly, the second reinforcing portion 344 is disposed on the other axial side of the second rotor core 302. The second reinforcing portion 344 faces or contacts the other surface of the second rotor core 302 in the axial direction. The second reinforcing portion 344 covers at least a part of the opening at the upper end of the magnet housing portion 32 of the second rotor core 302. As a result, in the second rotor core 302, the magnet 31 is prevented from coming off the magnet housing portion 32 in the axial direction. At least a portion of the second extending portion 342 is accommodated in the recess 33 of the second rotor core 302. Thus, in the second rotor core 302, the second extending portion 342 can press the bridge portion 36, and rattling of the magnet 31 housed in the magnet housing portion 32 can be suppressed.

The first rotor core 301 and the second rotor core 302 are arranged to be offset in the circumferential direction. Therefore, in the circumferential direction, the position of the first extending portion 341 is different from the position of the second extending portion 342. In other words, the first extending portion 341 does not face or contact the second extending portion 342 in the axial direction. Note that, even when the first rotor core 301 and the second rotor core 302 are offset in the circumferential direction, at least a portion of the end of the first extending portion 341 is at least a portion of the end of the second extending portion 342; It may be opposed or in contact.

Preferably, the length of the first extending portion 341 is the same as the axial length of the first rotor core 301 or shorter than the axial length of the first rotor core 301. The length of the second extending portion 342 is the same as the axial length of the second rotor core 302 or shorter than the axial length of the second rotor core 302. The axial length of the first extending portion 341 is longer than the axial length of the first rotor core 301, and the axial length of the second extending portion 342 is shorter than the axial length of the second rotor core 302. Good. In this case, the axial length of the second extending portion 342 is short by the dimension between the end of the first extending portion 341 and the other surface of the first rotor core 301 in the axial direction. In addition, the axial length of the first extending portion 341 is longer than the axial length of the first rotor core 301, and the axial length of the second extending portion 342 is longer than the axial length of the second rotor core 302. Good. In this case, at least a part of the tip on the other side in the axial direction of the first extension part 341 radially overlaps with at least a part of the tip on the one side in the axial direction of the second extension part 342.

The rotor core 30 may have a skew structure in which the electromagnetic steel plates 30b are stacked with a predetermined angle in the circumferential direction with the central axis C as a center. In this case, it is preferable that the first extending portion 341 be extended in the circumferential direction by being inclined to the central axis C by the predetermined angle.

<5. Third Modified Example>

FIG. 10 is a perspective view showing a state in which the shaft 4 of the rotor 3 of the third modified example of the present embodiment is attached. As shown in FIG. 10, in this modification, the first reinforcing portion 343 and the second reinforcing portion 344 are omitted from the pressing member 34, and the pressing member 34 is configured by the first extending portion 341. In the present modification, the axial length of the first extending portion 341 (the pressing member 34) is substantially the same as the axial length of the rotor core 30.

The axial length of the first extending portion 341 (the pressing member 34) may be different from the axial length of the rotor core 30. For example, the axial length of the first extending portion 341 (the pressing member 34) may be shorter than the axial length of the rotor core 30. In this case, at least one of the axial direction one side and the axial direction other side end face of the first extending portion 341 is located in the recess 33. In addition, the end surface of the first extending portion 341 on the one side in the axial direction and the end surface on the other side in the axial direction may be flush with the end surface on the one side in the axial direction of the rotor core 30 and the other end. Only the end surface on the one axial direction side or the other axial direction side of the first extending portion 341 may be flush with the end surface on the axial direction one side or the other axial direction side of the rotor core 30.

The rotor 3 includes a cylindrical holding member 38 which covers the circumferential surface of the rotor core 30 and presses the first extending portion 341 (the pressing member 34) radially inward. The holding member 38 is made of, for example, a nonmagnetic material such as resin or aluminum. The axial length of the holding member 38 is substantially the same as the axial length of the rotor core 30. The holding member 38 can move the first extending portion 341 more radially inward. Thereby, the first extending portion 341 can further press the bridge portion 36, and rattling of the magnet 31 positioned in the magnet housing portion 32 can be further suppressed.

<6. Fourth Modified Example>

The shape of the holding member 38 is not limited to a tubular shape, and may be, for example, a band-like ring shape as shown in FIG. In FIG. 11, the ring-shaped holding member 38 is disposed at the upper axial portion and the lower axial portion. As a result, the first extending portion 341 (the pressing member 34) can be easily tightened toward the magnet 31 side, and rattling of the magnet 31 in the magnet housing portion 32 can be further suppressed. The ring-shaped holding member 38 may be disposed only at the axial center, or may be disposed at the axial upper portion, the axial lower portion, and the axial center. The number of ring-shaped holding members 38 attached to the rotor core 30 may be one or two or more. Also, the rotor 3 may have both a cylindrical holding member 38 and a ring-shaped holding member 38. Further, when viewed from the axial direction, the shape of the holding member 38 is not limited to a circular shape, and may be, for example, a polygonal shape. In addition, the holding member 38 may be configured by a heat-shrinkable tube that shrinks by heating.

<7. Fifth modified example>

FIG. 12 is a plan view showing a rotor 3 of a fifth modified example of the present embodiment. In the present modification, the circumferential width of the recess 33 is substantially constant from the radially inner side to the radially outer side in the state before the pressing member 34 is disposed. In the present modification, the rotor core 30 is formed only of the electromagnetic steel plate 30 b having the bridge portion 36. That is, the rotor core 30 of the present modification does not have the space 37.

The pressing member 34 of this modification is a round bar-like member extending in the axial direction. That is, the shape of the cross section perpendicular to the axial direction of the pressing member 34 is circular. Thereby, the pressing member 34 can be easily formed. The rod-shaped pressing member 34 is not limited to a round rod. The shape of the cross section perpendicular to the axial direction of the rod-like pressing member 34 may be, for example, an elliptical shape or a polygonal shape including a rectangle, and is not particularly limited.

When the pressing member 34 is disposed in the recess 33, the pressing member 34 presses the magnet 31 radially inward via the bridge portion 36. At this time, the bridge portion 36 is deformed in the radial direction. Further, the pressing member 34 is sandwiched by the magnetic pole portions 35 adjacent in the circumferential direction. At this time, the holding member 38 may be attached to the rotor 3. Thereby, the radial outward movement of the pressing member 34 can be restricted. Further, since the pressing member 34 presses the bridge portion 36, the gap between the inner wall 32a of the magnet housing portion 32 and the outer peripheral surface of the magnet 31 can be reduced. Thereby, rattling of the magnet 31 in the magnet housing portion 32 can be further suppressed.

<8. Sixth modification>

FIG. 13 is an enlarged plan view of a part of the peripheral portion of the rotor 3 according to a sixth modification of the present embodiment. The magnet housing portion 32 of the present modification is a through hole having an opening 39 at the radially outer side and penetrating the rotor core 30 in the axial direction. The opening 39 extends radially and extends from one axial end of the rotor core 30 to the other axial end. In other words, the bridge portion 36 is not disposed on the opening 39 side of the magnet housing portion 32.

The recess 33 communicates with the magnet housing portion 32 through the opening 39. The pressing member 34 in the recess 33 contacts the magnet 31 through the opening 39. Then, the pressing member 34 directly presses the magnet 31 radially inward. Thereby, rattling of the magnet 31 in the magnet housing portion 32 can be suppressed. Since the magnet housing portion 32 has the opening 39, the magnet 31 can be easily stored in the magnet housing portion 32 via the opening 39. The pressing member 34 can restrict circumferential movement of the magnet 31 through the opening 39.

In the case where the recess 33 communicates with the magnet housing portion 32 through the opening 39, the pressing member 34 may not necessarily be in contact with the magnet 31. In this case, it is desirable that the inner wall 32 a of the magnet housing portion 32 be at least in radial contact with the magnet 31. In other words, the bridge portion 36 may not necessarily be continuously formed in the circumferential direction, and a part of the bridge portion 36 may be discontinuously formed in the circumferential direction. The pressing member 34 presses a portion of the inner wall located inward in the radial direction of the recess 33 (that is, a portion of the bridge portion 36 formed discontinuously), via the inner wall 32 a of the magnet housing portion 32. The magnet 31 can be pressed. As a result, even when the recess 33 communicates with the magnet housing 32 through the opening 39, rattling of the magnet 31 in the magnet housing 32 can be suppressed. When the recess 33 communicates with the magnet housing portion 32 through the opening 39, a member such as resin or metal may be disposed in the radial gap between the pressing member 34 and the magnet 31. The pressing member 34 may indirectly press the magnet 31 via the member.

<9. Other>

The embodiment of the present invention has been described above, but the scope of the present invention is not limited to this, and various modifications can be made without departing from the scope of the invention. In addition, the above-described embodiment and the modifications thereof can be arbitrarily combined arbitrarily.

Embodiments of the present disclosure can be widely used in various devices including various motors such as a vacuum cleaner, a dryer, a sealing fan, a washing machine, a refrigerator, an electric power steering apparatus, an electric oil pump, and an electric brake.

1: Motor, 2: Stator, 21: Stator core, 21a: Core back, 22: Insulator, 23: Coil, 3: Rotor, 30: Rotor core, 30a: Hole, 30b: Magnetic steel plate, 31: Magnet, 32: Magnet Housing portion 32a: inner wall, 33: recess, 331: narrow portion, 332: inner narrow portion, 333: outer narrow portion, 34: pressing member, 341: first extending portion, 342: second extending portion, 343: first reinforcement portion 344: second reinforcement portion 35: magnetic pole portion 36: bridge portion 37: space portion 38: holding member 39: opening portion 4: shaft C: central axis L1: Width, W1: Width, W2: longest width, W3: shortest width

Claims

A rotor core disposed along a central axis extending up and down;

A plurality of magnets arranged circumferentially on the rotor core;

Equipped with

The rotor core has a plurality of magnet housing portions that are arranged in the circumferential direction, housing at least a part of the magnets.

The magnet housing portion extends radially outward from the central axis side,

A recess which is recessed radially inward from an outer peripheral surface of the rotor core is provided radially outward of the magnet housing portion,

A rotor, in which at least a part of a pressing member for pressing the magnet radially inward directly or indirectly is disposed in the recess.
The recess communicates with the magnet housing portion,

The rotor according to claim 1, wherein the pressing member directly presses the magnet.
The recess communicates with the magnet housing portion,

The inner wall of the recess has a bridge portion connected to the inner wall of the magnet housing portion,

The rotor according to claim 1, wherein the pressing member presses the magnet via the bridge portion.
The inner wall of the recess has a bridge portion connected to the inner wall of the magnet housing portion,

The rotor according to claim 1, wherein the pressing member presses the magnet via the bridge portion.
The pressing member is

A first reinforcing portion located on one side in the axial direction of the rotor core;

A first extension portion extending from the first reinforcement portion to the other side in the axial direction, and at least a part of which is accommodated in the recess;

Have

The rotor according to claim 1, wherein the first extending portion presses the magnet directly or indirectly.
The recess communicates with the magnet housing portion,

The rotor according to claim 5, wherein the first extending portion directly presses the magnet.
The recess communicates with the magnet housing portion,

The inner wall of the recess has a bridge portion connected to the inner wall of the magnet housing portion,

The rotor according to claim 5, wherein the first extending portion presses the magnet via the bridge portion.
The inner wall of the recess has a bridge portion connected to the inner wall of the magnet housing portion,

The rotor according to claim 5, wherein the first extending portion presses the magnet via the bridge portion.
The pressing member is further

A second reinforcing portion located on the other side in the axial direction of the rotor core;

A second extending portion that extends from the second reinforcing portion to the one side in the axial direction, and at least a portion of which is accommodated in the recess;

Have

The tip on the other side in the axial direction of the first extending portion contacts or faces the tip on the one side in the axial direction of the second extending portion,

The first extending portion and the second extending portion directly or indirectly press the magnet.

The rotor according to claim 5.
The recess communicates with the magnet housing portion,

The rotor according to claim 9, wherein the first extending portion and the second extending portion directly press the magnet.
The recess communicates with the magnet housing portion,

The inner wall of the recess has a bridge portion connected to the inner wall of the magnet housing portion,

The rotor according to claim 9, wherein the first extending portion and the second extending portion press the magnet via the bridge portion.
The inner wall of the recess has a bridge portion connected to the inner wall of the magnet housing portion,

The rotor according to claim 9, wherein the first extending portion and the second extending portion press the magnet via the bridge portion.
The rotor according to any one of claims 1 to 4, wherein the pressing member is in the form of an axially extending rod.
The rotor according to any one of claims 1 to 13, further comprising a holding member that covers the circumferential surface of the rotor core and presses the pressing member radially inward.
The rotor according to any one of claims 1 to 14, wherein the pressing member is a nonmagnetic material.
A rotor according to any one of the preceding claims;

With the stator,

Motor.