WO2019064747A1

WO2019064747A1 - Rotor and motor comprising rotor

Info

Publication number: WO2019064747A1
Application number: PCT/JP2018/023720
Authority: WO
Inventors: 古舘　栄次
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
Also published as: CN212462909U

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; and circumferential wall parts that constitute at least parts of inside walls of the magnet housing parts. Recesses that are recessed from an outer circumferential surface of the rotor core toward the radial direction inside are provided between magnet housing parts that are adjacent in the circumferential direction. Pressing members that press the circumferential wall parts toward the magnets 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. It has a plurality of magnet housing parts which accommodate a part and are arranged in the circumferential direction, and a peripheral wall which constitutes at least a part of the inner side wall of each of the magnet housing parts, and is adjacent to the circumferential direction A recess is provided between the magnet housings and recessed radially inward from the outer peripheral surface of the rotor core, and a pressing member for pressing the peripheral wall toward the magnet 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 side view showing a state in which a shaft of a rotor according to an embodiment of the present invention is attached. FIG. 5 is a perspective view showing a state before the pressing member of the rotor according to the embodiment of the present invention is disposed in the recess. FIG. 6 is a plan view showing a state before the pressing member of the rotor according to the embodiment of the present invention is disposed in the recess. FIG. 7 is a perspective view of a pressing member of a rotor according to an embodiment of the present invention. FIG. 8 is a plan view of a pressing member of a rotor according to an embodiment of the present invention. FIG. 9 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. 10 is a side 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. 11 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. 12 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. 13 is a perspective view showing a state in which a shaft of a rotor according to a fourth modification of the embodiment of the present invention is attached. FIG. 14 is a perspective view of a rotor according to a fifth modification of the embodiment of the present invention. FIG. 15 is a plan view of a rotor according to a fifth modification of the embodiment of the present invention. FIG. 16 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. FIG. 17 is an enlarged plan view enlarging a part of a peripheral portion of a rotor according to a seventh modified example of the embodiment of the present invention. FIG. 18 is an enlarged plan view enlarging a part of a peripheral portion of a rotor according to an eighth modified embodiment of the embodiment of the present invention. FIG. 19 is an enlarged plan view enlarging a part of a peripheral portion of a rotor according to a ninth modified embodiment 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. However, 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 side view of the rotor 3 to which the shaft 4 is attached. FIG. 5 is a perspective 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. FIG. FIG. 6 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. 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 magnet housing portions 32 and a plurality of peripheral wall portions 35. 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. In the present embodiment, the shape of the cross section perpendicular to the axial direction in the inner side surface of the magnet housing portion 32 is a rectangular shape extending in the circumferential direction.

The 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. 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 circumferential direction. In other words, in the present embodiment, the shape of the magnet 31 is a plate extending in the axial 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 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 accommodated in the magnet accommodating portion 32, and may be a shape in which the side surface in the radial direction is a curved surface or the like, 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.

The circumferential wall portion 35 is disposed radially outside the magnet housing portion 32 and constitutes at least a part of the inner side wall 32 a of each magnet housing portion 32. The inner side 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. The inner side wall 32a includes a circumferential end 32b (see FIG. 6) disposed on at least one circumferential side of the magnet housing 32 and a plurality of bridge portions 36 connecting the circumferential end 32b and the circumferential wall 35. And.

In each magnet housing portion 32, the bridge portion 36 has an outer portion 36a and an inner portion 36b. When viewed from the axial direction, the outer side portion 36 a extends in the direction (one side or the other side in the circumferential direction) away from the magnet 31 as it goes radially inward from the peripheral wall 35. When viewed in the axial direction, the inner portion 36b extends in the direction approaching the magnet 31 (the other side or one side in the circumferential direction) as it goes radially inward from the tip of the outer portion 36a. That is, when viewed in the axial direction, the bridge portions 36 adjacent in the circumferential direction are bent in directions approaching each other. In other words, when viewed from the axial direction, the bridge portion 36 located on one side in the circumferential direction protrudes toward the bridge portion 36 located on the other side in the circumferential direction, and the bridge portion 36 located on the other side in the circumferential direction It protrudes toward the bridge part 36 located in circumferential direction one side.

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.

Between the magnet accommodating parts 32 adjacent in the circumferential direction, a recessed part 33 recessed inward in the radial direction from the outer peripheral surface of the rotor core 30 is provided. The recess 33 extends from one axial end to the lower axial end of the rotor core 30. The inner side wall of the recess 33 includes a bridge portion 36.

As shown in FIG. 6, 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. Then, in the recess 33, a first extending portion 341 (pressing member 34) described later is disposed.

FIG. 7 is a perspective view of the pressing member 34. As shown in FIG. FIG. 8 is a plan view of the pressing member 34. As shown in FIG. The pressing member 34 has a first reinforcing portion 343 and a plurality of first extending portions 341. 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. However, 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 first extending portion 341 by, for example, welding or welding. The circumferential width L1 (see FIG. 8) of the pressing member 34 in the inner wide portion 332 is larger than the narrow portion 331 and smaller than the circumferential maximum width W2 (see FIG. 6) of the inner wide portion 332. 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. Note that at least a portion 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 outer end portion of the first extending portion 341 presses the outer portion 36a of the bridge portion 36 radially inward, and the bridge portion 36 is elastically deformed. Do. At this time, since the peripheral wall portion 35 is connected to the bridge portion 36, the peripheral wall portion 35 also moves radially inward. That is, the first extending portion 341 of the pressing member 34 presses the peripheral wall 35 toward the magnet 31. Thereby, in the magnet housing portion 32, the gap in the radial direction between the peripheral wall portion 35 and the magnet 31 and the gap in the radial direction between the inner side wall 32a on the inner 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 side wall 32 a 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 bridge portion 36 includes the inner side wall of the recess 33, and the pressing member 34 presses the bridge portion 36 at least radially inward. Thus, the pressing member 34 can press the peripheral wall 35 toward the magnet 31 via the bridge portion 36 without contacting the pressing member 34 with the radially outer surface of the peripheral wall 35. Therefore, the increase in the radial length of the rotor 3 can be suppressed.

The circumferential width of the pressing member 34 in the inner wide portion 332 is larger than the narrow portion 331 and smaller than the circumferential maximum width of the inner wide portion 332. Thus, it is possible to prevent the radial outward displacement of the pressing member 34. Therefore, rattling of the magnet 31 can be further suppressed. Further, the width of the outer wide portion 333 in the circumferential direction is made wider than the narrow portion 331, and magnetic flux leakage in the circumferential direction of the magnet 31 can be reduced when the motor 1 rotates as described later.

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.

<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. 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 radial gap between the peripheral wall portion 35 and the magnet 31 by the pressing member 34 and the radial direction of the magnet 31 and the inner side wall 32a on the inner peripheral side of the magnet housing portion 32. 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. Thereby, in the magnet housing portion 32, the clearance in the radial direction between the peripheral wall portion 35 and the magnet 31 and the clearance in the radial direction between the inner side wall 32a on the inner peripheral side of the magnet housing portion 32 and the magnet 31 are further reduced. Thus, it is possible to further suppress the rattling of the magnet 31 housed in the magnet housing portion 32.

<3. First Modified Example>

FIG. 9 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. FIG. 10 is a side view showing a state in which the shaft 4 of the rotor 3 of the first modification is attached. 9 and 10 show a state in which the second extending portion 342 of the pressing member 34 is being inserted into the recess 33.

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 second extending portion 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 peripheral wall portion 35 to the magnet 31 side. Thereby, in the magnet housing portion 32, the gap in the radial direction between the peripheral wall portion 35 and the magnet 31 and the gap in the radial direction between the inner side wall 32a on the inner 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. Further, the second extending portion 342 can be reinforced by the second reinforcing portion 344. The second reinforcing portion 344 can improve the workability at the time of inserting the plurality of second extending portions 342 into the concave portion 33.

<4. Second Modified Example>

FIG. 11 is a side view showing a state in which the shaft 4 of the rotor 3 of the second modified example of the present embodiment is attached. 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 the axially lower side (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. However, even if 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.

Furthermore, 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 extend in the circumferential direction at a predetermined angle with respect to the central axis C.

<5. Third Modified Example>

FIG. 12 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. 12, 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 positioned in the recess 33. In addition, the end surface on the one axial direction side and the other axial direction side of the first extending portion 341 may be flush with the end surface on the axial direction one side and the other axial direction side of the rotor core 30, respectively. 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 further includes a cylindrical holding member 38 covering the outer peripheral surface of the rotor core 30 and pressing at least the peripheral wall portion 35 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 prevent the first extending portion 341 from moving radially outward. As a result, the first extending portion 341 can press the bridge portion 16 more, 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 cylindrical shape, and may be, for example, a band-like ring shape as shown in FIG. In FIG. 13, the ring-shaped holding member 38 is disposed at the axially upper portion and the axially lower portion. Thereby, the peripheral wall portion 35 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. 14 is a perspective view of a rotor 3 according to a fifth modification of the present embodiment. FIG. 15 is a plan view of a rotor 3 according to a fifth modification. In the present modification, as viewed in the axial direction, the circumferential width of the recess 33 gradually increases toward the radially outer side. 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 peripheral wall 35 toward the magnet 31 via the pressing of the bridge 36. In other words, the bridge portion 36 constituting each magnet housing portion 32 is pressed toward the magnet 31 located inside the magnet housing portion 32. At this time, the bridge portions 36 adjacent in the circumferential direction deform in directions away from each other. Thus, the pressing member 34 is sandwiched by the bridge portions 36 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 of the magnet housing portion 32 and the outer 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. 16 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 on one circumferential side and penetrating the rotor core 30 in the axial direction. The opening 39 penetrates to one side in the circumferential direction, 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 contacts or opposes the magnet 31 through the opening 39. Further, the end portion on the opening 39 side of the pressing member 34 contacts the radially outer surface of the peripheral wall 35 and presses radially inward. 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.

<9. Seventh Modified Example>

FIG. 17 is an enlarged plan view of a part of the peripheral portion of the rotor 3 according to a seventh modification of the present embodiment. The bridge portion 36 of the rotor 3 of the present modification has a first extending portion 36 c, a second extending portion 36 d, and a third extending portion 36 e. The first extending portion 36 c extends radially inward from the peripheral wall 35. The second extending portion 36 d extends from the radially inner end of the first extending portion 36 c to the side away from the magnet 31 in the circumferential direction (the side on which the adjacent bridge portion 36 is located). The third extending portion 36 e extends radially inward from the tip of the second extending portion 36 d. That is, the bridge portion 36 extends inward in the radial direction from the peripheral wall portion 35, and is bent in the circumferential direction away from the magnet 31 and then extends inward in the radial direction. Thus, the bridge portions 36 adjacent in the circumferential direction are bent in directions approaching each other.

The pressing member 34 disposed in the recess 33 presses the circumferential wall 35 to the magnet 31 side by pressing radially inward at least one of the first extending portion 36 c, the second extending portion 36 d, and the third extending portion 36 e. Press to. By providing the second extending portion 36 d, the pressing member 34 can easily press the bridge portion 36 and the peripheral wall portion 35 radially inward. As a result, the gap between the inner wall of the magnet housing portion 32 and the outer surface of the magnet 31 can be reduced. Thereby, rattling of the magnet 31 in the magnet housing portion 32 can be further suppressed.

<10. Eighth Modification>

FIG. 18 is an enlarged plan view of a part of the peripheral portion of the rotor 3 according to an eighth modification of the present embodiment. In the rotor 3 of this modification, the two outer side portions 36a adjacent in the circumferential direction are connected to the radially outer end of one inner side portion 36b. That is, the bridge portions 36 adjacent in the circumferential direction are connected to each other. The pressing member 34 disposed in the recess 33 presses the outer side portion 36 a radially inward. Therefore, the gap between the inner wall of the magnet housing portion 32 and the outer surface of the magnet 31 can be reduced. Thereby, rattling of the magnet 31 in the magnet housing portion 32 can be further suppressed.

<11. Ninth Modified Example>

FIG. 19 is an enlarged plan view of a part of the peripheral edge portion of a rotor 3 according to a ninth modified example of the present embodiment. In the rotor 3 of this modification, the bridge portion 36 is omitted. Thus, the pressing member 34 can be easily disposed in the recess 33. In the present modification, the pressing member 34 presses the radially outer surface of the peripheral wall 35 radially inward. Thus, the gap between the inner wall of the magnet housing portion 32 and the outer surface of the magnet 31 can be reduced. As a result, rattling of the magnet 31 in the magnet housing portion 32 can be further suppressed.

<12. 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.

DESCRIPTION OF SYMBOLS 1 ...

Motor

2, 2 ... Stator, 21 ... Stator core, 21a ... Core back, 22 ... Insulator, 23 ... Coil, 3 ... Rotor, 30 ... Rotor core, 301 ... 1st rotor core, 302 ... 2nd rotor core, 30a ... hole, 30b ... magnetic steel plate, 31 ... magnet, 32 ... magnet housing part, 32a ... inner wall, 32b: circumferential end, 33: recessed portion, 331: narrow portion, 332: inner narrow portion, 333: outer narrow portion, 34: pressing member, 341, ··· First extending portion, 342 ··· Second extending portion, 343 · · · First reinforcing portion, 344 · · · Second reinforcing portion, 35 · · · Peripheral wall portion, 36 · · · Bridge portion, 36a · · · · · · Outer part, 36b · · · inner part, 36c · · · first extension, 36d · · · Second extension portion 36 e: Third extension 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 is

A plurality of magnet accommodating portions that accommodate at least a part of the magnets and are arranged in the circumferential direction;

A peripheral wall portion constituting at least a part of an inner side wall of each of the magnet housing portions;

Have

Between the magnet housing portions adjacent in the circumferential direction, there is provided a recess which is recessed radially inward from the outer peripheral surface of the rotor core,

In the rotor, a pressing member for pressing the peripheral wall portion to the magnet side is disposed.
The magnet housing portion is a through hole penetrating in the axial direction,

The peripheral wall portion is at least a part of an inner side wall constituting the magnet housing portion,

The inner side wall of the magnet housing portion is

A circumferential end disposed on at least one circumferential side of the magnet housing portion;

A plurality of bridge portions connecting the circumferential end portion and the peripheral wall portion;

Have

The inner wall of the recess includes the bridge portion,

The rotor according to claim 1, wherein the pressing member presses the bridge portion at least radially inward.
The magnet housing portion is a through hole having an opening on one side in the circumferential direction and penetrating in the axial direction,

The recess communicates with the magnet housing through the opening,

The rotor according to claim 1, wherein the pressing member contacts or opposes the magnet through the opening.
The recess is

The narrow part,

An outer wide portion disposed radially outward of the narrow portion and having a circumferential width greater than that of the narrow portion;

An inner wide portion disposed radially inward of the narrow portion and having a circumferential width greater than that of the narrow portion;

Have

The circumferential width of the pressing member in the inner wide portion is larger than the narrow portion, and smaller than the longest circumferential width of the inner wide portion in any one of claims 1 to 3. Description rotor.
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 any one of claims 1 to 4, wherein the first extending portion presses the peripheral wall portion to the magnet side.
The pressing member is

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

A second extension portion extending from the second reinforcement portion to the one axial direction side and at least a part 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 rotor according to claim 5, wherein the second extending portion presses the peripheral wall portion to the magnet side.
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 7, further comprising a holding member that covers an outer peripheral surface of the rotor core and presses at least the circumferential wall portion radially inward.
The rotor according to any one of claims 1 to 8, wherein the pressing member is a nonmagnetic material.
A rotor according to any one of the preceding claims;

With the stator,

Motor.