WO2019003802A1

WO2019003802A1 - Rotor, motor, and rotor production method

Info

Publication number: WO2019003802A1
Application number: PCT/JP2018/021172
Authority: WO
Inventors: 真郷青野; 貴之右田; 晃弘大北
Original assignee: 日本電産株式会社
Priority date: 2017-06-29
Filing date: 2018-06-01
Publication date: 2019-01-03
Also published as: CN212063658U

Abstract

A rotor comprising: a shaft arranged along a center axis extending in the vertical direction; a rotor core fixed to the shaft; a plurality of magnets positioned on the outside of the rotor core, in the radial direction, and lined up along the circumferential direction; a rotor cover having a cylindrical section that surrounds the rotor core and the magnets from the outside of the magnets in the radial direction and a floor section positioned in the opening on the lower side of the cylindrical section; and an end section cap positioned on the upper side of the rotor core and magnets and fixed to the cylindrical section. The end section cap has: a plate section extending along a direction orthogonal to the center axis; a first convex section arranged around the center axis, protruding downwards from the plate section, and coming in contact with the upper surface of the rotor core; and a second convex section arranged around the center axis, protruding downwards from the plate section, and coming in contact with the upper surface of the magnets.

Description

Rotor, motor and method of manufacturing rotor

The present invention relates to a rotor, a motor and a method of manufacturing the rotor.

A rotor comprising a rotor core and a rotor cover covering a permanent magnet, and a motor comprising such a rotor are known (e.g. U.S. Pat. No. 5,075,015).

JP, 2011-30406, A

In the rotor as described above, it is necessary to fix the rotor core and the permanent magnet to the rotor cover. When the rotor core and the permanent magnet are bonded and fixed to the rotor cover, a waiting time for curing the adhesive is generated in the manufacturing process, which causes a problem that manufacturing efficiency is poor. In addition, when the lid is fixed to one end of the rotor cover, and the rotor core and the permanent magnet are pressed and fixed by the lid, the gap between the lid and the rotor core or the permanent magnet is caused by the variation in axial dimension of the rotor core and the permanent magnet. There is a problem that a gap is generated and rattling occurs in the rotor core.

In view of the above circumstances, the present invention provides a rotor having a rotor cover and a magnet on a rotor cover without using an adhesive and suppressing rattling, a motor including such a rotor, and a method of manufacturing the rotor. One of the purposes is to provide.

One aspect of the rotor according to the present invention is a shaft disposed along a central axis extending in the vertical direction, a rotor core fixed to the shaft, and a plurality of radial outer sides of the rotor core and arranged along the circumferential direction A rotor cover having a magnet, a cylindrical portion surrounding the rotor core and the magnet from the radially outer side of the magnet, and a bottom portion positioned at an opening on the lower side of the cylindrical portion; and a position above the rotor core and the magnet An end cap fixed to the cylindrical portion, the end cap being a plate portion extending in a direction orthogonal to the central axis, and the plate disposed around the central axis A first convex portion projecting downward from the ring-shaped portion and in contact with the upper surface of the rotor core; and a convex portion disposed around the central axis and projecting downward from the plate-shaped portion Having a second convex portion that contacts with.

One aspect of the motor of the present invention includes the above-described rotor, and a stator that faces the rotor in the radial direction via a gap.

According to one aspect of the present invention, a rotor for fixing a rotor core and a magnet to a rotor cover without using an adhesive and suppressing rattling, a motor including such a rotor, and a method of manufacturing the rotor Is provided.

FIG. 1 is a schematic cross-sectional view of a motor according to an embodiment. FIG. 2 is an exploded perspective view of the rotor of an embodiment. FIG. 3 is a cross-sectional view of the rotor of one embodiment. FIG. 4 is a perspective view of an end cap of one embodiment. FIG. 5 is a perspective view for describing a part of a second step in the process of manufacturing a rotor according to an embodiment. FIG. 6 is a perspective view for explaining a part of a second step in the process of manufacturing a rotor according to an embodiment. FIG. 7 is a perspective view for explaining a part of a second step in the process of manufacturing a rotor according to an embodiment. FIG. 8 is a cross-sectional view of a rotor of a modification. FIG. 9 is a perspective view of a modified end cap.

FIG. 1 is a schematic cross-sectional view of a motor 10 according to the present embodiment.

The motor 10 includes a housing 11, a stator 12, a rotor 13 having a shaft 20 disposed along a vertically extending central axis J, a bearing holder 14, and

bearings

15 and 16. The stator 12 opposes the rotor 13 via the radial gap on the radially outer side of the rotor 13. The shaft 20 is rotatably supported by the

bearings

15 and 16. The shaft 20 has a cylindrical shape extending in the axial direction.

In each figure, the Z axis is shown as appropriate. The Z-axis direction of each drawing is a direction parallel to the axial direction of the central axis J shown in FIG. In the following description, the positive side in the Z-axis direction (+ Z side, one side) is referred to as “upper side”, and the negative side in the Z-axis direction (−Z side, other side) as “lower side”. Call. Note that the upper and lower sides are directions used merely for the purpose of explanation, and do not limit the actual positional relationship or direction. Further, unless otherwise noted, a direction (Z-axis direction) parallel to the central axis J is simply referred to as “axial direction” or “vertical direction”, and a radial direction centered on the central axis J is simply referred to as “radial direction”. The circumferential direction around the central axis J, that is, around the axis of the central axis J, is simply referred to as “circumferential direction”. Furthermore, in the following description, “plan view” means a state viewed from the axial direction. Moreover, in the following drawings, in order to make each structure intelligible, a scale, the number, etc. in an actual structure and each structure may be varied.

FIG. 2 is an exploded perspective view of the rotor 13. FIG. 3 is a cross-sectional view of the rotor 13. In FIG. 2, the illustration of the shaft 20 is omitted.

The rotor 13 includes a shaft 20 (see FIG. 4), a rotor core 30, a plurality of magnets 40, a rotor cover 60, and an end cap 50.

As shown in FIG. 2, the rotor core 30 is in the form of an axially extending column. Although not shown, the rotor core 30 is configured, for example, by laminating a plurality of plate members in the axial direction. The rotor core 30 has a rotor core main body 31 and a plurality of projections 33 located on the outer peripheral surface of the rotor core main body 31.

The rotor core body 31 extends in the axial direction. More specifically, the rotor core main body 31 is a regular octagonal prism centered on the central axis J. The rotor core body 31 has a plurality of magnet support surfaces 32. The magnet support surface 32 extends in the axial direction. The magnet support surface 32 is a flat surface orthogonal to the radial direction. The plurality of magnet support surfaces 32 form a plurality of radially outer side surfaces of the rotor core main body 31 having a regular octagonal columnar shape.

The rotor core main body 31 has a fixing hole 31 a penetrating the rotor core main body 31 in the axial direction. The shape viewed along the axial direction of the fixing hole portion 31 a is a circular shape centering on the central axis J. The shaft 20 is passed through the fixing hole 31a. The inner peripheral surface of the fixing hole 31 a is fixed to the outer peripheral surface of the shaft 20. The rotor core 30 is thereby fixed to the shaft 20.

The protrusion 33 protrudes radially outward from the rotor core main body 31. The protrusion 33 extends from the upper end portion of the rotor core main body 31 to the lower end portion of the rotor core main body 31. The radially outer surface of the protrusion 33 is a flat surface orthogonal to the radial direction. The dimension in the circumferential direction of the protrusion 33 increases from the radially inner side toward the radially outer side. The plurality of protrusions 33 are arranged side by side along the circumferential direction. The circumferential intervals of the plurality of protrusions 33 are, for example, the same as one another. The number of the plurality of protrusions 33 is, for example, eight. The eight projections 33 project radially outward from the respective corners of the regular octagonal columnar rotor core body 31.

The rotor core 30 is provided with a plurality of core through holes (recesses) 34 penetrating the rotor core 30 in the axial direction. The core through hole 34 penetrates the rotor core main body 31 in the axial direction. The plurality of core through holes 34 are arranged at equal intervals along the circumferential direction. The circumferential intervals of the plurality of core through holes 34 are, for example, equal to one another. The core through holes 34 are circular when viewed along the axial direction. The number of core through holes 34 is, for example, eight. Each core through hole 34 is located radially inward of the different magnets 40. Some of the core through holes 34 among the plurality of core through holes 34 function as concave portions into which third convex portions 53 described later are inserted.

The magnet 40 has a substantially square prism shape that is flat in the radial direction and extends in the axial direction. The magnet 40 is located radially outward of the rotor core 30. The plurality of magnets 40 are arranged along the circumferential direction. More specifically, the plurality of magnets 40 are arranged at equal intervals along the circumferential direction.

Each magnet 40 is arrange | positioned between the projection parts 33 adjacent to the circumferential direction. The end portions on both sides in the circumferential direction of the magnet 40 are in contact with the protrusions 33 adjacent on both sides in the circumferential direction of the magnet 40. More specifically, the radially inner ends of the circumferential ends of the magnet 40 are in contact with the protrusions 33. The magnet 40 is positioned in the circumferential direction by contacting the protrusion 33.

Each magnet 40 is supported by the magnet support surface 32 from the inside in the radial direction. The radially inner side surface of the magnet 40 is a flat surface orthogonal to the radial direction, and is in contact with the magnet support surface 32. The radially outer side surface of the magnet 40 is a curved surface which is curved in the circumferential direction along the radially inner side surface of a cylindrical portion 61 of the rotor cover 60 described later. The center of curvature of the radially outer surface of the magnet 40 coincides with the central axis J. By making the radial direction outer side surface of the magnet 40 into such a curved surface, the magnetic characteristic of the motor 10 can be improved. The radially outer side surface of the magnet 40 contacts the radially inner side surface of the rotor cover 60. Thereby, the magnet 40 is pinched in the radial direction in a state of being in contact with the rotor core 30 and the rotor cover 60.

As shown in FIG. 3, the axial design dimension of the magnet 40 is the same as the axial design dimension of the rotor core 30. The upper surface 40 a of the magnet 40 and the upper surface 30 a of the rotor core 30 are disposed on substantially the same plane orthogonal to the axial direction. The lower surface 40 b of the magnet 40 and the lower surface 30 b of the rotor core 30 are disposed on substantially the same plane orthogonal to the axial direction.

The rotor cover 60 has a cylindrical portion 61 and a bottom portion 62. The rotor cover 60 is made of a metal material. The cylindrical portion 61 has a tubular shape extending in the axial direction. More specifically, the cylindrical portion 61 is cylindrical around the central axis J. The cylindrical portion 61 opens on both sides in the axial direction. The cylindrical portion 61 surrounds the rotor core 30 and the magnet 40 from the radially outer side of the magnet.

The upper end portion 61 c of the cylindrical portion 61 is provided with an inner protruding portion 63 extending inward in the radial direction. The inner projecting portion 63 is formed by plastically deforming the upper end portion 61c (see FIG. 2) of the cylindrical portion 61 linearly extending along the axial direction (see FIG. 2) radially inward. The inner projection 63 contacts the upper surface 50 a of the end cap 50. In addition, the inner protrusion 63 presses the end cap 50 against the rotor core 30 and the magnet 40 to fix the end cap 50 to the cylindrical portion 61. The inner protrusion 63 is provided with a fixing projection 64 described later with reference to FIG. The fixing recess 55 d fits into the fixing recess 55 d of the end cap 50 to suppress the rotation of the end cap 50 with respect to the rotor cover 60.

The bottom portion 62 is located at the lower opening 61 b of the cylindrical portion. The bottom portion 62 extends radially inward from the cylindrical portion 61. The bottom portion 62 is provided with a shaft passage hole 62c. The plan view shape of the shaft passing hole 62c is a circle centered on the central axis J. The diameter of the shaft passage hole 62 c is larger than the diameter of the shaft 20. The shaft 20 is passed through the shaft passage hole 62c. The bottom portion 62 is located below the rotor core 30 and the plurality of magnets 40. The lower surface 30 b of the rotor core 30 and the lower surfaces 40 b of the plurality of magnets 40 are in contact with the upper surface 62 a of the bottom portion 62. Thus, the rotor core 30 and the plurality of magnets 40 are supported by the bottom portion 62 from the lower side.

The end cap 50 is located on the upper side of the rotor core 30 and the magnet 40 and covers the rotor core 30 and the magnet 40 from the upper side. The end cap 50 is located radially inward of the cylindrical portion 61. The end cap 50 is housed in the rotor cover 60. The end cap 50 is made of, for example, a resin material.

FIG. 4 is a perspective view of the end cap 50. The end cap 50 includes a disk-shaped plate-like portion 55, a plurality of (four in the present embodiment) first convex portions 51, a plurality of second convex portions 52, and a plurality (two in the present embodiment) And the third convex portion 53). The first convex portion 51, the second convex portion 52 and the third convex portion 53 are provided on the lower surface 55 b of the plate-like portion 55.

The plate-like portion 55 extends in the direction orthogonal to the central axis J. The outer shape in plan view of the plate-like portion 55 is circular. The outer diameter of the plate-like portion 55 is slightly smaller than the inner diameter of the cylindrical portion 61. The outer peripheral edge of the plate-like portion 55 is located inside the cylindrical portion 61.

The plate-like portion 55 is provided with a shaft passing hole 55c. The plan view shape of the shaft passage hole 55c is a circle whose center is the central axis J. The diameter of the shaft passage hole 55 c is sufficiently larger than the diameter of the shaft 20. The shaft 20 is passed through the shaft passage hole 55c.

The first convex portion 51, the second convex portion 52, and the third convex portion 53 protrude downward from the plate-like portion 55. The first convex portion 51, the second convex portion 52, and the third convex portion 53 are disposed around the central axis J, respectively. That is, the first convex portion 51, the second convex portion 52, and the third convex portion 53 are disposed on an imaginary circle centered on the central axis J in plan view. Regarding the distance from the central axis J in plan view, the second convex portion 52 is the longest, the first convex portion 51 is the second longest, and the third convex portion 53 is the shortest.

The plurality of first protrusions 51 are arranged at equal intervals around the central axis J. The plurality of first convex portions 51 overlap the rotor core 30 as viewed from the axial direction. The planar view shape of each 1st convex part 51 is circular. In the state of a single component before the end cap 50 is assembled to the rotor 13, the tip of the first convex portion 51 is curved in a hemispherical shape. In the following description, the state of the single component before the end cap 50 is assembled to the rotor 13 is simply referred to as the "component state". Further, the state after the end cap 50 is assembled to the rotor 13 is simply referred to as "assembled state".

As shown in FIG. 3, the first convex portion 51 is in contact with the upper surface 30 a of the rotor core 30. In the assembled state, the first convex portion 51 is plastically deformed in accordance with the surface shape of the upper surface 30 a of the rotor core 30. Further, as described above, the end cap 50 is pressed to the rotor core 30 and the magnet 40 by the inner protruding portion 63 of the rotor cover 60. For this reason, the first convex portion 51 is elastically deformed in the axial direction to generate a repulsive force between the inner protruding portion 63 and the rotor core 30.

The axial length (protruding dimension h1) in the component state of the first convex portion 51 is longer than the distance between the lower surface 55b of the plate-like portion 55 and the upper surface 30a of the rotor core 30 in the assembled state. Therefore, the first convex portion 51 deforms and reliably contacts the upper surface 30 a of the rotor core 30.

The second convex portion 52 extends annularly along the circumferential direction. The lower surface 52 b of the second convex portion 52 overlaps with each of the plurality of magnets 40 as viewed from the axial direction. The second convex portion 52 contacts the upper surface 40 a of the magnet 40 at the lower surface 52 b. Further, the lower surface 52 b of the second convex portion 52 is located outside the outer peripheral edge of the rotor core 30 as viewed in the axial direction. Therefore, the second convex portion 52 does not contact the upper surface 30 a of the rotor core 30.

The height of the component state of the second convex portion 52 substantially matches the distance between the lower surface 55 b of the plate-like portion 55 and the upper surface 30 a of the rotor core 30 in the assembled state. That is, the second convex portion 52 hardly deforms before and after assembly. In other words, the protrusion dimension h2 of the second protrusion 52 hardly changes before and after the assembly. Therefore, the projection dimension h2 of the second convex portion 52 is a reference dimension that determines the distance between the lower surface 55b of the plate-like portion 55 and the upper surface 30a of the rotor core 30 in the assembled state. In the present specification, the “projecting dimension” means the axial distance from the lower surface 55 b of the plate-like portion 55 to the tip of the convex portion.

In the component state, the protrusion dimension h1 of the first protrusion 51 is larger than the protrusion dimension h2 of the second protrusion 52. Further, in the assembled state, the protrusion dimension h1a of the first protrusion 51 matches the protrusion dimension h2 of the second protrusion 52. In other words, the first convex portion 51 is deformed to have substantially the same height as the second convex portion 52 in the assembling process.

According to the present embodiment, since the first convex portion 51 and the second convex portion 52 individually project from the plate-like portion 55, it is difficult for one deformation to affect the other. Therefore, at least one of the first convex portion 51 and the second convex portion 52 is deformed to press the

upper surfaces

30a and 40a of the rotor core 30 and the magnet 40 from the upper side to the lower side to move the rotor core 30 and the magnet 40 in the axial direction. It can suppress the occurrence of rattling.

According to the present embodiment, the plurality of first protrusions 51 are arranged at equal intervals around the central axis J. On the other hand, the second convex portion 52 extends annularly around the central axis J. Therefore, the first convex portion 51 is easily deformed relative to the second convex portion 52, and the first convex portion 51 can be deformed based on the protrusion dimension h2 of the second convex portion 52.

Generally, since the rotor core 30 and the magnet 40 are manufactured separately, the axial dimension may vary. If it is attempted to press the rotor core and the magnet on the same surface of the end cap, a gap may be generated between one of the rotor core 30 and the magnet 40 and the end cap, which may cause rattling.

According to the present embodiment, since the projection dimension h1 of the first projection 51 is larger than the projection dimension h2 of the second projection 52, the first projection 52 is a first contact with the magnet 40 as a reference. Can be deformed until it sufficiently contacts the magnet 40. That is, the first convex portion 51 can be in contact with the upper surface 30 a of the rotor core 30 without a gap, and the second convex portion 52 can be in contact with the upper surface 40 a of the magnet 40 without a gap. As a result, the end cap 50 can press and fix the rotor core 30 and the magnet 40 simultaneously to the bottom 62 of the rotor cover 60.

In addition, if the protrusion dimension of any one of the 1st convex part 51 and the 2nd convex part 52 is larger than the protrusion size of the other, rattling of the rotor core 30 and the magnet 40 can be suppressed. That is, one of the larger projecting dimensions can be plastically or elastically deformed until the other contacts the upper surface of the opposing rotor core 30 or magnet 40. Thereby, the first convex portion 51 and the second convex portion 52 can be brought into contact with the rotor core 30 and the magnet 40 without any gap, and rattling of the rotor core 30 and the magnet 40 can be suppressed.

According to the present embodiment, the first convex portion 51 and the second convex portion 52 are disposed around the central axis J. More specifically, the plurality of first protrusions 51 are arranged at equal intervals around the central axis J, and the second protrusions 52 are annularly arranged around the central axis J. For this reason, the end cap 50 applies a force to the rotor core 30 and the plurality of magnets 40 uniformly in the circumferential direction with respect to the central axis J via the first convex portion 51 and the second convex portion 52. Can. As a result, the rotor core 30 and the plurality of magnets 40 can be pressed to the bottom 62 in a balanced manner, and the rotor core 30 and the plurality of magnets 40 can be stably fixed to the rotor cover 60.

According to the present embodiment, the second convex portion 52 is provided annularly around the central axis J. The end cap 50 of this embodiment is made of a resin material and manufactured by injection molding. By making the second convex portion 52 annular, the lower surface 52 b of the second convex portion 52 can be formed as a surface derived from the same surface in the mold, and the dimensional accuracy of the lower surface 52 b can be enhanced. it can. As described above, the protrusion dimension h2 of the second convex portion 52 is a reference dimension that determines the distance between the lower surface 55b of the plate-like portion 55 and the upper surface 30a of the rotor core 30 in the assembled state. According to the present embodiment, by forming the second convex portion 52 in a continuous ring shape, the dimensional accuracy of the lower surface 52 b of the second convex portion 52 can be enhanced, and as a result, the axial direction of the rotor 13 is obtained. The dimensional accuracy of the

The plurality of third protrusions 53 are arranged at equal intervals around the central axis J. The plan view shape of the third convex portion 53 is circular. The protrusion dimension of the third protrusion 53 is larger than the protrusion dimension of the first protrusion 51 and the second protrusion 52. The third convex portion 53 is inserted into the core through hole (concave portion) 34 of the rotor core 30. Thus, the circumferential position of the end cap 50 can be positioned with respect to the rotor core 30.

In addition, although the 2nd 3rd convex part 53 is provided in the edge part cap 50 of this embodiment, one or more 3rd convex parts 53 should just be provided.

Further, the recess of the rotor core 30 into which the third protrusion 53 is inserted may not be the core through hole 34 penetrating the rotor core 30, as long as the recess is a shape that is recessed downward from the upper surface 30a. In the present specification, the core through hole 34 is an aspect of the recess provided on the upper surface 30 a of the rotor core 30.

Next, a method of manufacturing the rotor 13 will be described.

First, in the first step, the rotor core 30 and the plurality of magnets 40 are accommodated inside the cylindrical portion 61 of the rotor cover 60. Thereby, the lower surface 30b of the rotor core 30 and the lower surfaces 40b of the plurality of magnets 40 are brought into contact with the bottom portion 62 of the rotor cover 60 (see FIG. 3).

Next, a second step of fixing the end cap 50 to the cylindrical portion 61 of the rotor cover 60 is performed. 5 to 7 are perspective views for explaining the second step in the manufacturing process of the rotor 13.

In the second step, as shown in FIG. 5, first, the end cap 50 is disposed on the inner side of the cylindrical portion 61 and above the rotor core 30 and the plurality of magnets 40. At this time, the third convex portion 53 of the end cap 50 is inserted into the core through hole 34 of the rotor core 30. Further, the end cap 50 is pressed downward by using a jig (not shown). Thus, the first convex portion 51 of the end cap 50 is plastically deformed (see FIG. 3).

As shown in FIG. 5, a plurality of (four in the present embodiment) fixing recesses 55 d are provided on the outer peripheral edge of the end cap 50. The fixing recess 55d is recessed radially inward. The fixing recess 55d is recessed downward from the upper surface 50a. The four fixed recesses 55d are arranged at equal intervals around the central axis J.

Next, as shown in FIG. 6, the upper end portion 61 c of the cylindrical portion 61 is plastically deformed inward in the radial direction to form the inner protruding portion 63. The inner projecting portion 63 is formed by pressing the upper end portion 61c from outside in the radial direction against the rotor cover 60 while pressing a caulking jig (not shown) around the central axis J, and bending the upper end portion 61c inward. Be done. The inner protrusion 63 may be formed by lowering a die (not shown) relative to the upper end 61 c of the rotor cover 60 and pressing the upper end 61 c of the cylindrical portion 61 radially inward.

The inner protrusion 63 contacts the outer peripheral edge of the upper surface 50 a of the end cap 50. The inner protrusion 63 presses the end cap 50 against the rotor core 30 and the magnet 40. More specifically, as shown in FIG. 3, the inner protrusion 63 brings the second protrusion 52 into contact with the upper surfaces 40 a of the plurality of magnets 40 and elastically deforms the first protrusion 51, while the upper surface of the rotor core 30 is Contact 30a. When the end cap 50 is sandwiched between the inward projection 63 and the rotor core 30, the first convex portion 51 is elastically deformed and the repulsive force of the first convex portion 51 causes the end cap 50 to be attached to the rotor cover 60. It is fixed. The second convex portion 52 may also be elastically deformed along with the first convex portion 51.

According to the manufacturing method of the present embodiment, the second step of fixing the end cap 50 to the cylindrical portion 61 includes the step of deforming the first convex portion 51. Therefore, it is possible to provide the rotor 13 in which the rattling of the rotor core 30 and the magnet 40 is suppressed by bringing the first convex portion 51 and the second convex portion of the end cap into contact with the rotor core 30 and the magnet 40, respectively.

In the present embodiment, the process of plastically deforming the first protrusion 51 and the process of caulking the inner protrusion 63 and elastically deforming the first protrusion 51 are separately performed. did. However, these steps may be performed simultaneously. That is, when the inner protrusion 63 is formed by caulking, the first protrusion 51 may be plastically and elastically deformed.

Further, in the present embodiment, only the first convex portion 51 is deformed in the second step, but the first convex portion 51 is brought into contact with the upper surface 30 a of the rotor core 30 and the second convex portion 52 is made of the magnet 40. The step of deforming one or both of the first convex portion 51 and the second convex portion 52 may be used as long as the upper surface 40 a of the second convex portion 52 is in contact with the upper surface 40 a.

According to the present embodiment, the second step includes the step of deforming the upper end portion 61 c of the cylindrical portion 61 to provide the inner protruding portion 63. In this process, the inner projection 63 can be brought into contact with the upper surface 50 a of the end cap 50, and the end cap 50 can be pressed against the rotor core 30 and the magnet 40 to fix the end cap 50.

Next, as shown in FIG. 7, a part of the inner protrusion 63 is deformed to form the fixing protrusion 64. The fixing convex portion 64 protrudes downward as well as dents the upper surface of the inner protruding portion 63 downward. More specifically, the fixed convex portion 64 is formed by striking a jig (not shown) from the upper side to the inner protruding portion 63 to deform. The fixing projection 64 is fitted in a fixing recess 55 d provided on the outer peripheral edge of the end cap 50.

According to the present embodiment, the second step includes the step of deforming the cylindrical portion 61 to provide the fixing projection 64. The fixing convex portion 64 positions the end cap 50 in the circumferential direction with respect to the cylindrical portion 61 in order to fit in the fixing concave portion 55 d. Thereby, even if vibration occurs, the rotation of the end cap 50 is suppressed, and the first convex portion 51 and the second convex portion 52 move relative to the rotor core 30 and the magnet 40. There is no Therefore, since the first convex portion 51 and the second convex portion 52 are in stable contact with the rotor core 30 and the magnet 40, the rotor core 30 and the magnet 40 can be stably fixed to the rotor cover 60.

The step of caulking the inner protrusion 63 and the step of forming the fixing projection 64 may be performed in the same step.

According to the method of manufacturing the rotor 13 of this embodiment, it is possible to manufacture the rotor 13 in which the rotor core 30 and the magnet 40 are fixed to the rotor cover 60 without using an adhesive and suppressing rattling. Therefore, according to this embodiment, the inexpensive and high-performance rotor 13 can be provided.

(Modification)

FIG. 8 is a cross-sectional view of a rotor 113 of a modification of the above-described embodiment. FIG. 9 is a perspective view of an end cap 150 of a rotor 113 of a modification. The rotor 113 of this modification mainly differs from the above-described rotor 13 in the structure of the end cap 150. In addition, about the component of the aspect same as the above-mentioned embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

As shown in FIG. 8, and similarly to the above-described embodiment, the end cap 150 of the rotor 113 is pressed against the rotor core 30 and the magnet by the inner projecting portion 63 provided on the upper end portion 61 c of the cylindrical portion 61. And fixed to the tubular portion 61.

As shown in FIG. 9, the end cap 150 includes a disk-shaped plate-like portion 155, a first convex portion 151, a plurality (eight in this modification) of a second convex portion 152, and a plurality (two) In the modification, two third convex portions 153 are provided.

The plate-like portion 155 extends in a direction perpendicular to the central axis J. The outer shape of the plate-like portion 155 in a plan view is a circular shape slightly smaller than the inner diameter of the cylindrical portion 61. The plate-like portion 155 is provided with a shaft passage hole 155 c through which the shaft 20 passes.

The first convex portion 151 protrudes downward from the lower surface 155 b of the plate-like portion 155. The first convex portion 151 is disposed around the central axis J. More specifically, the first convex portion 151 extends annularly along the circumferential direction around the central axis J. The first protrusions 151 overlap the rotor core 30 as viewed in the axial direction.

The first convex portion 151 contacts the upper surface 30 a of the rotor core 30 at the lower surface 151 b. The height of the component state of the first convex portion 151 substantially matches the distance between the lower surface 155 b of the plate-like portion 155 and the upper surface 30 a of the rotor core 30 in the assembled state. That is, the first convex portion 151 hardly deforms before and after assembly, and the protrusion dimension h101 of the first convex portion 151 does not change before and after assembly. Therefore, the protrusion dimension h101 of the first convex portion 151 is a reference dimension that determines the distance between the lower surface 155b of the plate-like portion 155 and the upper surface 30a of the rotor core 30 in the assembled state.

The plurality of second projections 152 are arranged at equal intervals around the central axis J. Each of the plurality of second convex portions 152 overlaps the different magnet 40 among the plurality of magnets 40 when viewed in the axial direction. That is, in the present modification, the end cap 150 has eight second convex portions 152 equal in number to the magnet 40, and the respective second convex portions 152 axially face the different magnets 40. The plan view shape of each second convex portion 152 is circular. The tip of the second protrusion 152 is hemispherically curved.

As shown in FIG. 8, each of the second protrusions 152 contacts the top surface 40 a of a different magnet 40. In the assembled state, the second convex portion 152 is plastically deformed in accordance with the surface shape of the upper surface 40 a of the magnet 40. The protrusion dimension h102 in the component state of the second convex portion 152 is longer than the distance between the lower surface 155b of the plate-like portion 155 and the upper surface 40a of the magnet 40 in the assembled state. Therefore, the second convex portion 152 is deformed and reliably contacts the upper surface 40 a of the magnet 40.

In the component state, the protrusion dimension h102 of the second protrusion 152 is larger than the protrusion dimension h101 of the first protrusion 151. Further, in the assembled state, the protrusion dimension h102a of the second protrusion 152 matches the protrusion dimension h101 of the first protrusion 151. In other words, the second convex portion 152 is deformed to have substantially the same height as the first convex portion 151 in the assembling process.

According to this modification, as in the above-described embodiment, since the first convex portion 151 and the second convex portion 152 individually project from the plate-like portion 155, one deformation affects the other. Hard to give. Therefore, at least one of the first convex portion 151 and the second convex portion 152 is deformed to press the

upper surfaces

30a and 40a of the rotor core 30 and the magnet 40 from the upper side to the lower side, and the axial direction of the rotor core 30 and the magnet 40 It can suppress the occurrence of rattling.

According to this modification, the plurality of second convex portions 152 contact the upper surfaces 40 a of the magnets 40 different from each other. In general, the plurality of magnets 40 may have variations in axial dimensions. According to this modification, the second convex portions 152 individually contact the upper surface 40 a of the magnet 40 and deform according to the size of the magnet 40. For this reason, it is possible to suppress the rattling of the magnet 40 by absorbing the dimensional variations of the respective magnets 40 by the deformation of the respective second convex portions 152.

The plurality of third convex portions 153 are arranged at equal intervals around the central axis J. In the present modification, the third convex portion 153 protrudes downward from the lower surface 151 b of the first convex portion 151. The third convex portion 153 is inserted into the core through hole 34 of the rotor core 30 as in the above-described embodiment. Thus, the circumferential position of the end cap 150 can be positioned with respect to the rotor core 30. Further, since the end cap 150 is positioned in the circumferential direction with respect to the rotor core 30 and the magnet 40, the plurality of second projections 152 can be reliably brought into contact with the different magnets 40.

Although one embodiment and its modification of the present invention were explained above, each composition in the embodiment and modification, combination thereof, etc. are an example, and addition of composition is within the range which does not deviate from the meaning of the present invention. , Omissions, substitutions and other modifications are possible. Further, the present invention is not limited by the embodiments.

For example, the application of the motor provided with the rotor of the embodiment described above and its variation is not particularly limited. The motor including the rotors of the above-described embodiment and the modification thereof is mounted on, for example, an electric pump, an electric power steering, and the like.

In the above-mentioned embodiment (or its modification), the 1st convex part 51 (or the 2nd convex part 152) carries out plastic deformation and elastic deformation. However, the first convex portion 51 (or the second convex portion 152) may absorb the axial difference between the rotor core 30 and the magnet 40 only by elastic deformation without plastic deformation.

Moreover, in the above-mentioned embodiment (or its modification), the shape of the 1st convex part 51 (or 2nd convex part 152) is an example. For example, the first convex portion 51 (or the second convex portion 152) may have another shape such as a conical shape which is easily deformed plastically and elastically. The shaft 20 is not limited to a solid, and may be a hollow member. In each embodiment described above, the number of magnets 40 is eight (ie, the number of poles is eight). However, the number of magnetic poles of the rotor may be changed as appropriate. The shape of the magnet 40 is not limited to the one described above, and may be another shape. The rotor core body 31 is not limited to the octagonal prismatic shape, and may be a polygonal pillar or a cylindrical shape depending on the shape and the number of the magnets 40, and is not particularly limited. The bearing holder 14 may be integral with a lid member covering the opening of the housing 11.

DESCRIPTION OF SYMBOLS 10 Motor 12 stator 13 13 rotor 13 shaft 30 rotor core 34 core through hole (recess) 40

magnet

50, 150

end cap

51, 151 first Convex part 52, 152: second convex part 53, 153: third convex part 55, 155: plate-like part, 55 d: fixed concave part 60: rotor cover, 61: cylindrical part, 61 c: upper end Sections 62: bottom portions 63: inner protrusions 64: fixed protrusions h1, h2, h101, h102: projecting dimensions J: central axis, Z: axial direction

Claims

A shaft disposed along a vertically extending central axis,

A rotor core fixed to the shaft;

A plurality of magnets located radially outward of the rotor core and aligned along a circumferential direction;

A rotor cover having a cylindrical portion surrounding the rotor core and the magnet from the radially outer side of the magnet, and a bottom portion positioned at an opening on the lower side of the cylindrical portion;

An end cap located above the rotor core and the magnet and fixed to the tubular portion;

Equipped with

The end cap is

A plate-like portion extending along a direction orthogonal to the central axis;

A first convex portion disposed around the central axis, protruding downward from the plate-like portion, and in contact with the upper surface of the rotor core;

A second convex portion disposed around the central axis, protruding downward from the plate-like portion, and in contact with the upper surface of the magnet;

Have

Rotor.
One of the first convex portion and the second convex portion has a projection dimension larger than the other.

The rotor according to claim 1.
The end cap has a plurality of the first protrusions aligned around the central axis,

The protrusion dimension of the first protrusion is larger than the protrusion dimension of the second protrusion.

The rotor according to claim 1.
The end cap has a plurality of the second protrusions aligned around the central axis,

The projecting dimension of the second convex portion is larger than the projecting dimension of the first convex portion,

The plurality of second protrusions contact the upper surfaces of the different magnets, respectively

The rotor according to claim 1.
The end cap has a third protrusion projecting downward from the plate-like portion,

The upper surface of the rotor core is provided with a recess into which the third protrusion is inserted.

A rotor according to any one of the preceding claims.
The upper end portion of the cylindrical portion is provided with an inner protruding portion extending radially inward,

The inner projection contacts the top surface of the end cap and presses the end cap against the rotor core and the magnet to secure the end cap.

The rotor according to any one of claims 1 to 5.
The outer peripheral edge of the end cap is provided with a fixed recess that is recessed radially inward,

The cylindrical portion is provided with a fixing protrusion that fits into the fixing recess.

A rotor according to any one of the preceding claims.
A rotor according to any one of claims 1 to 7;

A stator that faces the rotor in the radial direction via a gap;

Equipped with a motor.
A rotor cover having a cylindrical portion extending along a vertically extending central axis and a bottom portion positioned at an opening on the lower side of the cylindrical portion, the rotor core and a plurality of radial outer portions of the rotor core A first step of storing the magnet of

Fixing the rotor core and an end cap located on the upper side of the magnet to the tubular portion;

Have

The end cap is

A plate-like portion extending along a direction orthogonal to the central axis;

A first convex portion that overlaps with the rotor core as viewed in the axial direction and is disposed around the central axis and protrudes downward from the plate-like portion;

A second convex portion that overlaps with the magnet as viewed in the axial direction and is disposed around the central axis and protrudes downward from the plate-like portion;

Have

The second step is

Either or both of the first convex portion and the second convex portion are deformed to bring the first convex portion into contact with the upper surface of the rotor core, and the second convex portion to be the upper surface of the magnet Contacting, including the process,

Method of manufacturing a rotor.
The second step is

The upper end of the cylindrical portion is deformed to provide an inner protrusion extending radially inward, the inner protrusion being in contact with the upper surface of the end cap, and the end cap being pressed against the rotor core and the magnet Securing the end cap, including the steps of

A method of manufacturing a rotor according to claim 9.
The outer peripheral edge of the end cap is provided with a fixed recess that is recessed radially inward,

The second step includes a step of deforming the cylindrical portion to provide a fixing projection that fits into the fixing recess.

A method of manufacturing a rotor according to claim 9 or 10.