JP2019054615A - motor - Google Patents

Abstract

To accurately adjust a rotation balance of a rotor without impairing the appearance.SOLUTION: A motor 100 includes: a rotor 110 which may rotate around a rotation shaft 111; and a stator 120 which drives the rotor. The rotor has: a cylindrical housing 1; and a lid part 2 which is attached to an upper end part in an axial direction of the housing. The lid part has: a disk part 23 which is formed with a rotation axis set to its center and extends in a radial direction; a protruding part 24 which protrudes from the disk part to the axial lower side; and a balance adjustment member 25 for adjusting a rotation balance of the rotor. The balance adjustment member is provided on a protruding part inner surface 24a in a radial direction of the protruding part at the axial upper side relative to the stator.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a motor.

  Conventionally, a motor provided with a member for adjusting the rotational balance of the rotor is known. For example, in Patent Document 1, a balance weight is attached to, for example, the outer end surface and the lower portion of the inner peripheral surface of the rotor yoke in order to eliminate fluctuations in the dynamic balance of the rotor portion.

JP 2001-298925 A

  However, if a balance weight is attached to the outer end face of the rotor yoke, the balance weight is exposed and visible from the outside, so that the appearance of the motor is deteriorated. Therefore, for example, it is necessary to disassemble the motor and then attach the balance weight, assemble the motor again, adjust the balance of the rotor portion, and make it invisible from the outside. However, it is difficult to adjust the balance of the rotor portion, which takes time. Furthermore, since the balance weight is at the lower end in the axial direction, it is difficult to accurately adjust the rotation balance of the rotor portion.

  An object of the present invention is to accurately adjust the rotation balance of a rotor without impairing the appearance.

  An exemplary motor of the present invention includes a rotor that can rotate around a rotation axis, and a stator that drives the rotor. The rotor includes a cylindrical housing and a lid portion attached to an upper end portion in the axial direction of the housing. The lid part is a disk part centering on the rotation axis and extending in the radial direction, a convex part protruding downward in the axial direction from the disk part, and a balance adjusting member for adjusting the rotation balance of the rotor, Have The balance adjusting member is provided on the inner surface of the convex portion in the radial direction of the convex portion on the upper side in the axial direction than the stator.

  According to the exemplary motor of the present invention, the rotational balance of the rotor can be accurately adjusted without deteriorating the appearance.

FIG. 1 is a cross-sectional view showing a structural example of a motor. FIG. 2 is a perspective view showing the appearance of the motor. FIG. 3A is a perspective view of the lid portion viewed from the upper side in the axial direction. FIG. 3B is a perspective view of the lid viewed from the lower side in the axial direction. FIG. 4 is a cross-sectional view of the lid portion showing another configuration example of the inner surface of the convex portion. FIG. 5 is a diagram showing a cross-sectional structure including a wall portion and a protruding piece. FIG. 6A is a perspective view of a lid according to a first modification. FIG. 6B is a cross-sectional view illustrating a configuration of a lid according to a first modification. FIG. 6C is a cross-sectional view illustrating another configuration of the lid according to the first modification. FIG. 7A is a perspective view of a lid according to a second modification. FIG. 7B is a cross-sectional view illustrating a configuration of a lid according to a second modification. FIG. 7C is a cross-sectional view illustrating another configuration of the lid according to the second modification.

  Hereinafter, exemplary embodiments of the present invention will be described with reference to the drawings.

  In the present specification, in the motor 100, a direction parallel to the rotation axis RA is referred to as an “axial direction”. In the axial direction, a direction from the stator 120 described later toward the lid 2 described later is referred to as “axial upper side”, and a direction from the lid 2 toward the stator 120 is referred to as “axial lower side”. In each component, the end on the upper side in the axial direction is called “upper end”, and the end on the lower side in the axial direction is called “lower end”. Further, on the surface of each component, the surface facing the upper side in the axial direction is referred to as “upper surface”, and the surface facing the lower side in the axial direction is referred to as “lower surface”.

  Further, a direction orthogonal to the rotation axis RA is referred to as a “radial direction”, and a rotation direction around the rotation axis RA is referred to as a “circumferential direction”. In the radial direction, a direction toward the rotation axis RA is referred to as “radial inner side”, and a direction away from the rotation axis RA is referred to as “radial outer side”. In each component, an end portion on the radially inner side is referred to as an “inner end portion”, and an end portion on the radially outer side is referred to as an “outer end portion”. In addition, among the side surfaces of each component, a side surface facing the radially inner side is called an “inner side surface”, and a side surface facing the radially outer side is called an “outer side surface”.

  Of the side surfaces of each component, an inner side surface 1a of the housing 1 described later is referred to as a “housing inner side surface 1a”, and an inner side surface 24a of the convex portion 24 described later is referred to as a “convex portion inner side surface 24a”. Further, an outer surface 281a of the first wall 281 described later is referred to as a “first outer surface 281a”, and an outer surface 282a of the second wall 282 described later is referred to as a “second outer surface 282a”.

  Note that the names such as the direction, the end, and the surface described above do not indicate the positional relationship and the direction when incorporated in an actual device.

<1. Embodiment>
<1-1. Motor configuration>
FIG. 1 is a cross-sectional view showing a structural example of the motor 100. FIG. 2 is a perspective view showing the appearance of the motor 100. The motor 100 is mounted on, for example, a small unmanned airplane (not shown) and rotates the wings. Note that the motor 100 is not limited to this example, and the motor 100 may be mounted on, for example, transport machines such as automobiles and railways, OA equipment, medical equipment, tools, industrial large equipment, and the like to generate various driving forces. Good.

  The motor 100 includes a rotor 110, a stator 120, and a bearing bush 130.

  The rotor 110 is rotatable with respect to the stator 120 about a rotation axis RA extending in the vertical direction. The rotor 110 includes a shaft 111, a housing 1, a lid portion 2, and a magnet 3. The shaft 111 extends in the axial direction along the rotation axis RA and is rotatable about the rotation axis RA. The housing 1 has a cylindrical shape centered on the rotation axis RA. The housing 1 accommodates the stator 120 and the upper part of the bearing bush 130 therein. The lid portion 2 is attached to the upper end portion in the axial direction of the housing 1. The magnet 3 is disposed on the inner surface 1a of the housing, and a plurality of magnets 3 are arranged in the circumferential direction on the inner surface 1a of the housing. In the present embodiment, the motor 100 is an outer rotor type. That is, the plurality of magnets 3 are located radially outside the stator 120 and face the outer surface of the stator 120 in the radial direction. The configuration of the lid 2 will be described later.

  The stator 120 drives and rotates the rotor 110. The stator 120 includes a stator core 121 and a coil portion 122. Stator core 121 has an annular shape centering on rotation axis RA, and is made of, for example, a laminated steel plate in which a plurality of electromagnetic steel plates are laminated. Coil portion 122 is made of a conductive wire wound around stator core 121 via an insulator (not shown).

  The bearing bush 130 rotatably supports the shaft 111 via bearings 131a and 131b.

<1-2. Configuration of the lid>
Next, the configuration of the lid 2 will be described with reference to FIGS. 3A and 3B in addition to FIGS. FIG. 3A is a perspective view of the lid portion 2 as viewed from the upper side in the axial direction. FIG. 3B is a perspective view of the lid portion 2 as seen from the lower side in the axial direction.

  The lid part 2 includes a lid part opening 2a, a shaft coupling part 21, an output shaft part 22, a disk part 23, a convex part 24, a balance adjusting member 25, an annular part 26, a plurality of ribs 27, The wall portion 28 and a plurality of protruding pieces 29 are provided.

  The lid portion opening 2a is provided between the plurality of ribs 27 in the circumferential direction and between the disk portion 23 and the annular portion 26 in the axial direction (see FIG. 3A). In this way, when the rotor 110 rotates, an air flow through the lid opening 2a can be generated between the ribs 27. Further, each rib 27 scratches the air, so that the air flow becomes stronger. Due to the air flow, the inside of the motor 100 can be effectively cooled by the rotation of the motor 100.

  Even when the lid 2 is attached to the housing 1, the balance adjusting member 25 can be provided on the convex inner surface 24a through the lid opening 2a.

  The shaft connecting portion 21 is connected to the shaft 111. More specifically, in the present embodiment, an attachment hole 21a extending in the axial direction is provided at the lower end portion of the output shaft portion 22 (see FIG. 1). The upper end of the shaft 111 is fitted into the mounting hole 21a. The upper end portion of the shaft 111 and the shaft coupling portion 21 are coupled using, for example, an adhesive (not shown).

  For example, a propeller (not shown) having a plurality of blades is attached to the output shaft portion 22. For example, when the motor 100 is driven, the output shaft portion 22 outputs torque of the rotor 110 including the lid portion 2 to rotate the propeller.

  The disk part 23 is a circular plate shape centering on the rotation axis RA, and extends in the radial direction. In this embodiment, the disk portion 23 extends radially outward from the outer surface of the shaft coupling portion 21, but is not limited to this illustration, and may extend radially outward from the outer surface of the output shaft portion 22.

  The convex portion 24 protrudes downward from the disk portion 23 in the axial direction. More specifically, the convex part 24 protrudes from the outer end part of the disk part 23 in this embodiment. In the present embodiment, the convex inner surface 24a in the radial direction of the convex part 24 is parallel to the rotation axis RA. In this way, the balance adjusting member 25 can be held by the two surfaces of the convex inner surface 24 a and the lower surface of the disk portion 23 when the rotor 110 rotates. Accordingly, the balance adjusting member 25 can be stably held on the convex portion inner side surface 24a.

  In addition, the structure of the convex part inner surface 24a is not limited to this illustration. FIG. 4 is a cross-sectional view of the lid 2 showing another configuration example of the convex inner surface 24a. For example, as shown in FIG. 4, the convex inner surface 24 a may be an inclined surface that is inclined outward in the radial direction toward the lower side in the axial direction. If it does in this way, it will become easy to provide the balance adjustment member 25 in the convex part inner surface 24a.

  The first axial distance W1 in the axial direction between the upper end portion of the disk portion 23 and the lower end portion of the convex portion 24 is the second axial distance between the upper end portion of the disk portion 23 and the upper end portion of the annular portion 26. It is less than half of the axial distance W2 (see FIG. 1). If it does in this way, the balance adjustment member 25 can be hold | maintained to the convex part inner surface 24a, without preventing the flow of the air through the cover part opening 2a.

  The balance adjustment member 25 is a member for adjusting the rotational balance of the rotor 110. In the present embodiment, a composite resin material containing ceramic powder such as alumina is used for the balance adjusting member 25. The balance adjusting member 25 is provided on the inner surface 24 a of the convex portion in the radial direction of the convex portion 24 on the upper side in the axial direction from the stator 120. In this way, the balance adjustment member 25 is difficult to see from the outside of the lid 2. Further, the balance adjusting member 25 is provided on the inner surface 24 a of the convex portion on the upper side in the axial direction than the stator 120. Therefore, the rotational balance of the rotor 110 can be adjusted with high accuracy while actually driving the assembled motor, for example, without impairing the appearance. In addition, although the balance adjustment member 25 contacts the lower surface of the disk part 23 in this embodiment, it is not limited to this illustration, and may be separated from the lower surface of the disk part 23. In other words, the balance adjustment member 25 may be provided with a space between the lower surface of the disk portion 23.

  The annular portion 26 has an annular shape centered on the rotation axis RA. The annular portion 26 is located on the upper side in the axial direction from the wall portion 28, and is located on the lower side in the axial direction from the disk portion 23. That is, the annular part 26 is located between the wall part 28 and the disk part 23 in the axial direction. The annular portion 26 connects the plurality of ribs 27 in the circumferential direction.

  In the present embodiment, the rib 27 has a plate shape extending in the axial direction and the radial direction. The rib 27 connects between the disk portion 23 and the annular portion 26. A plurality of ribs 27 are arranged in the circumferential direction. The number of ribs 27 may be smaller than the number of protruding pieces 29, but is preferably more than the number of protruding pieces 29. In other words, the number of ribs 27 is preferably equal to or greater than the number of protruding pieces 29. If it is more than the number of the protrusion pieces 29, the flow of the air through the cover part opening 2a can be made stronger.

  The rib 27 extends in the axial direction and the radial direction at least on the lower side in the axial direction than the disk portion 23. More specifically, the rib 27 includes a convex plate portion 27a. The convex plate portion 27a extends from the lower surface of the disk portion 23 to the lower side in the axial direction, and further extends in the radial direction. In this way, when the rotor 110 rotates, an air flow can be generated between the ribs 27 through the lid opening 2a. Further, the air flow is strengthened by the convex plate portions 27a of the ribs 27 scratching the air. Due to the air flow, the inside of the motor 100 can be effectively cooled by the rotation of the motor 100.

  The inner end portion in the radial direction of each rib 27 may be connected to the shaft connecting portion 21 or the output shaft portion 22, but preferably at least the lower side in the axial direction than the disk portion 23. Are opposed to each other with a gap in the radial direction (see FIG. 3B). In other words, preferably, in at least one of the ribs 27, the inner end portion of the convex plate portion 27a is radially separated from the shaft connecting portion 21 and the output shaft portion 22 and connected to the shaft connecting portion 21 and the output shaft portion 22. Not. In this way, for example, the motor 100 can be reduced in weight compared to a configuration in which the inner end portion of each rib 27 is connected to the shaft coupling portion 21. Further, since the material used for forming the ribs 27 can be reduced, the cost can be reduced.

  Next, the wall 28 and the protruding piece 29 will be described with reference to FIG. FIG. 5 is a view showing a cross-sectional structure including the wall portion 28 and the protruding piece 29. 5 corresponds to a portion surrounded by a broken line in FIG.

  The wall portion 28 extends downward in the axial direction from the annular portion 26 and is located on the radially inner side of the housing 1. The wall portion 28 has an annular shape around the rotation axis RA and extends in the circumferential direction. The wall portion 28 includes a first wall portion 281 and a second wall portion 282.

  The first wall portion 281 contacts a part of the housing inner side surface 1 a in the radial direction of the housing 1. The first wall portion 281 has a cylindrical shape extending in the axial direction. That is, the housing inner surface 1a and the first outer surface 281a are both surfaces extending in the axial direction. In this way, the contact area where the first wall portion 281 contacts the inner surface of the housing 1 is increased, so that the mounting strength between the first wall portion 281 and the housing 1 is improved.

  The second wall portion 282 extends downward in the axial direction from the lower end portion in the axial direction of the first wall portion 281. The second wall portion 282 faces the housing inner surface 1a through the adhesive 28a. In other words, the second outer surface 282a is bonded to the housing inner surface 1a by the adhesive 28a.

  In the present embodiment, the second wall portion 282 has an annular shape centered on the rotation axis RA. However, the present invention is not limited to this example, and the second wall portion 282 may have, for example, an arc shape having a gap in a part in the circumferential direction and centering on the rotation axis RA. Alternatively, there may be a plurality of second wall portions 282, and the respective second wall portions 282 may be arranged with intervals in the circumferential direction.

  In the radial direction, the first radial distance L1 between the first outer surface 281a of the first wall portion 281 and the rotation axis RA is, as shown in FIG. 5, with the second outer surface 282a of the second wall portion 282. It is larger than the second radial distance L2 between the rotation axis RA. In this way, the lid portion 2 is provided with a portion where the first wall portion 281 contacts the housing inner side surface 1a and a portion where the second wall portion 282 is bonded to the housing inner side surface 1a by the adhesive 28a. Thereby, when the rotor 110 rotates, the load applied between the housing 1 and the lid part 2 can be distributed to each part. Therefore, it is possible to suppress the occurrence of a gap between the upper end portion in the axial direction of the housing 1 and the lid portion 2.

  Specifically, when the lid 2 is attached to the housing 1, for example, the first wall 281 is more closely spaced than the configuration in which the lid 2 is attached to the housing 1 only by adhesion using the adhesive 28a. While being in contact with the inner side surface 1a, it is guided axially downward along the inner side surface 1a of the housing. Therefore, it is possible to more easily attach the lid 2 to the housing 1 while suppressing the generation of a gap between the wall 28 and the housing 1. Further, the attachment angle between the direction in which the wall portion 28 extends and the direction in which the housing 1 extends becomes difficult to shift. Furthermore, the attachment position in the radial direction of the lid portion 2 with respect to the housing 1 is also difficult to shift. Accordingly, it is possible to improve the accuracy of attaching the lid portion 2 to the housing 1. Therefore, the balance accuracy of the rotor 110 during rotation can be improved.

  In the axial direction, the axial length D1 of the first wall portion 281 may be equal to or greater than the axial length D2 of the second wall portion 282, but preferably, as shown in FIG. It is smaller than the axial length D2. Thus, if D1 <D2, the safety factor of the load stress with respect to the proof stress of the wall part 28 improves compared with the structure which attaches the cover part 2 to the housing 1 only by contact with the wall part 28 and the housing 1, for example. . In other words, it is possible to improve the attachment strength of the lid portion 2 to the housing 1 while suppressing an increase in the load applied to the wall portion 28.

  The protruding piece 29 protrudes downward in the axial direction from the lower end portion in the axial direction of the wall portion 28. More specifically, the protruding pieces 29 protrude from the lower end portion in the axial direction of the second wall portion 282 in the axial direction and are arranged in the circumferential direction. Each protruding piece 29 is disposed between adjacent magnets 3. In this way, the magnet 3 can be positioned in the circumferential direction and the axial direction. Further, the protruding piece 29 extends from the lower end of the second wall portion 282 that is difficult to be loaded. Therefore, the accuracy of the position of the magnet 3 in the circumferential direction and the axial direction can be improved.

  The number of protruding pieces 29 may be different from the number of magnets 3, but is preferably the same as the number of magnets 3. If the number is the same, each magnet 3 can be guided between the protrusions 29 when the lid 2 is attached to the housing 1. Therefore, it becomes easy to attach the magnet 3 to the housing 1.

  Further, in each projecting piece 29, at least a part of the projecting piece 29 overlaps the rib 27 when viewed from the axial direction. If it carries out like this, it will become easy to shape | mold the cover part 2 using a metal mold | die, for example.

<2. Modification of lid>
Next, the 1st and 2nd modification of the cover part 2 is demonstrated. In the following description, a configuration different from the above-described embodiment will be mainly described. Moreover, in each modification, the same code | symbol is attached | subjected to the same component as the above-mentioned embodiment and another modification, and description of the same structure as the above-mentioned embodiment and another modification may be abbreviate | omitted.

<2-1. First Modification>
FIG. 6A is a perspective view of the lid 2 according to the first modification. FIG. 6B is a cross-sectional view showing the configuration of the lid 2 according to the first modification. FIG. 6C is a cross-sectional view showing another configuration of the lid 2 according to the first modification.

  In the lid part 2 according to the first modification, the disk part 23 includes a plate part 231, a ring part 232, and an upper opening 233. The plate portion 231 extends radially outward from the outer surface of the shaft coupling portion 21 and is located radially inward of the ring portion 232. The ring portion 232 has an annular shape centered on the rotation axis RA, and is connected to the plate portion 231 in the radial direction by a plurality of ribs 27. The axial position of the plate portion 231 is the same as the axial position of the ring portion 232. In other words, the plate portion 231 faces the ring portion 232 in the radial direction. The upper opening 233 opens in the axial direction. The upper opening 233 is provided between the plurality of ribs 27 in the circumferential direction and between the plate portion 231 and the ring portion 232 in the radial direction. In this way, air is communicated between the outside and the inside of the lid portion 2 through the upper opening 233. For this reason, the inside of the motor 100 is further easily cooled.

  The convex portion 24 protrudes from the ring portion 232 in the axially lower side. A balance adjusting member 25 is provided on the inner surface 24 a of the convex portion in the radial direction of the convex portion 24. The balance adjusting member 25 may be separated from the lower surface of the ring portion 232, but preferably contacts the lower surface of the ring portion 232.

  The convex inner surface 24a in the radial direction of the convex part 24 may be parallel to the rotation axis RA as shown in FIG. 6B. In this way, when the rotor 110 is rotated, the balance adjusting member 25 can be held by the two surfaces of the convex inner surface 24a and the lower surface of the ring portion 232, and the balance adjusting member 25 can be stably held in the convex portion. It can be held on the side surface 24a.

  Alternatively, the convex inner surface 24a may be an inclined surface that inclines radially outward as it goes downward in the axial direction, as shown in FIG. 6C. If it does in this way, it will become easy to provide the balance adjustment member 25 in the convex part inner surface 24a.

<2-2. Second Modification>
FIG. 7A is a perspective view of the lid 2 according to a second modification. FIG. 7B is a cross-sectional view showing the configuration of the lid 2 according to the second modification. FIG. 7C is a cross-sectional view illustrating another configuration of the lid 2 according to the second modification.

  In the lid part 2 according to the second modified example, the disk part 23 has a plate part 231, a ring part 232, and an upper opening 233 that opens in the axial direction, as in the first modified example. In the second modified example, the ring portion 232 is positioned on the lower side in the axial direction than the plate portion 231 as shown in FIGS. 7A to 7C.

  The convex portion 24 protrudes from the ring portion 232 in the axially lower side. A balance adjusting member 25 is provided on the inner surface 24 a of the convex portion in the radial direction of the convex portion 24. The balance adjustment member 25 may be separated from the lower surface of the ring portion 232, but preferably contacts the lower surface of the ring portion 232.

  The convex inner surface 24a in the radial direction of the convex portion 24 may be parallel to the rotation axis RA as shown in FIG. 7B, or is inclined radially outward as it goes downward in the axial direction as shown in FIG. 7C. It may be an inclined surface.

  Each rib 27 does not include the convex plate portion 27a in the second modification. In this case, for example, the motor 100 can be reduced in weight as compared with a configuration in which each rib 27 includes the convex plate portion 27a. Further, since the material used for forming the ribs 27 can be reduced, the cost can be reduced. Moreover, the internal space of the cover part 2 becomes wider.

<3. Other>
The embodiment of the present invention has been described above. The scope of the present invention is not limited to the above-described embodiment. The present invention can be implemented with various modifications without departing from the spirit of the invention. In addition, the items described in the above embodiments can be arbitrarily combined as long as no contradiction occurs.

  The present invention can be used for a motor in which a member for adjusting a rotation balance is provided in a rotor.

  DESCRIPTION OF SYMBOLS 100 ... Motor, 110 ... Rotor, 111 ... Shaft, 1 ... Housing, 1a ... Housing inner surface, 2 ... Cover part, 2a ... Cover part opening, 21 ...・ Axis connecting part, 21a ... Mounting hole, 22 ... Output shaft part, 23 ... Disk part, 231 ... Plate part, 232 ... Ring part, 233 ... Upper opening, 24 ..Convex part, 24a ... Inner side surface of convex part, 25 ... Balancing member, 26 ... annular part, 27 ... Rib, 27a ... Convex plate part, 28 ... Wall part, 28a ... Adhesive, 281 ... first wall, 281a ... first outer surface, 282 ... second wall, 282a ... second outer surface, 29 ... projecting piece, 3 ... Magnets, 120 ... Stator, 121 ... Stator core, 122 ... Coil part, 130 ... Bearin Bush, 131a, 131b ... bearing, RA ... rotation axis, L1 ... first radial distance, L2 ... second radial distance, D1, D2 ... axial length, W1. ..First axial distance, W2 ... Second axial distance

Claims (12)

A rotor rotatable about a rotation axis;
A stator for driving the rotor;
With
The rotor is
A tubular housing;
A lid attached to the upper end in the axial direction of the housing;
Have
The lid is
A disk portion centered on the rotation axis and extending in a radial direction;
A convex portion protruding downward in the axial direction from the disk portion;
A balance adjusting member for adjusting the rotational balance of the rotor;
Have
The balance adjusting member is a motor provided on the inner surface of the convex portion in the radial direction of the convex portion on the upper side in the axial direction than the stator.   The motor according to claim 1, wherein the inner surface of the convex portion is parallel to the rotation axis.   The motor according to claim 1, wherein the inner surface of the convex portion is an inclined surface that is inclined outward in the radial direction toward the lower side in the axial direction.   The motor according to any one of claims 1 to 3, wherein the disk portion further includes an upper opening that opens in an axial direction. The lid is
An annular portion located axially lower than the disk portion and centered on the rotational axis;
A plurality of ribs connecting the disk portion and the annular portion and arranged in a circumferential direction;
A lid opening provided between the ribs;
The motor according to any one of claims 1 to 4, further comprising:   The first distance in the axial direction between the upper end portion of the disk portion and the lower end portion of the convex portion is half the second distance in the axial direction between the upper end portion of the disk portion and the upper end portion of the annular portion. The motor according to claim 5, wherein:   The motor according to claim 5, wherein the rib extends in the axial direction and the radial direction at least on the lower side in the axial direction than the disk portion. The rotor further includes a shaft extending in the axial direction along the rotation axis and rotatable about the rotation axis;
The lid portion further includes a shaft coupling portion coupled to the shaft,
The inner end portion in the radial direction of each of the ribs is at least axially lower than the disk portion, and faces the shaft coupling portion with a radial interval therebetween. The motor described in. The rotor further includes a magnet arranged on the inner side surface in the radial direction of the housing and arranged in a plurality in the circumferential direction,
The lid is
A wall portion extending axially downward from the annular portion and positioned radially inside the housing;
A plurality of protruding pieces that protrude downward in the axial direction from the lower end portion in the axial direction of the wall portion and are arranged in the circumferential direction;
Further comprising
The motor according to claim 5, wherein the protruding piece is disposed between adjacent magnets.   The motor according to claim 9, wherein the number of the ribs is equal to or greater than the number of the protruding pieces.   The motor according to claim 9 or 10, wherein the number of the magnets is the same as the number of the protruding pieces.   The motor according to any one of claims 9 to 11, wherein at least a part of the protruding piece overlaps with the rib when viewed from the axial direction.

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