JP7047290B2 - motor - Google Patents

Description

The present invention relates to a motor.

Conventionally, a motor including a rotor in which a lid is connected to an annular housing is known. For example, in the motor of Patent Document 1, the head cover assembly is fitted to the annular housing of the rotor portion.

Chinese Patent Application Publication No. 105846600

However, in the motor of Patent Document 1, when the head cover assembly is press-fitted and fixed to the annular housing, a load is applied to the entire head cover assembly.

It should be noted that a method of adhering between the annular housing and the head cover assembly using an adhesive is also conceivable. However, when only the two are bonded using an adhesive, there is a gap between the two for providing the adhesive. Therefore, when the head cover assembly is fitted to the annular housing, the mounting angle of the head cover assembly with respect to the extending direction of the annular housing tends to deviate. In addition, the mounting position of the head cover assembly with respect to the annular housing in the radial direction is likely to shift. These cause the rotational balance of the rotor portion to deteriorate.

An object of the present invention is to provide a motor that suppresses deterioration of the rotational balance of the rotor portion while maintaining the fixing strength between the housing and the lid portion.

An exemplary motor of the present invention includes a rotor that can rotate about a rotation axis and a stator that drives the rotor. The rotor has a cylindrical housing and a lid attached to an axially upper end of the housing. The lid portion has a wall portion located inside the housing in the radial direction and extending in the circumferential direction, and the wall portion includes a first wall portion in contact with a part of the inner surface surface of the housing in the radial direction of the housing. It has a second wall portion extending downward in the axial direction from the lower end portion in the axial direction of the first wall portion. The first radial distance between the first outer surface of the first wall and the rotating shaft is the second radial distance between the second outer surface of the second wall and the rotating shaft. Greater than. The second outer surface faces the inner side surface of the housing via an adhesive , the rotor has a magnet, and the adhesive material comes into contact with the magnet.

According to the exemplary motor of the present invention, deterioration of the rotational balance of the rotor portion can be suppressed while maintaining the fixing strength between the housing and the lid portion.

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 seen from the upper side in the axial direction. FIG. 3B is a perspective view of the lid portion seen from the lower side in the axial direction. FIG. 4 is a cross-sectional view of a 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 motor showing a first modification of the lid portion. FIG. 6B is a cross-sectional view showing the configuration of the lid portion according to the first modification. FIG. 7A is a perspective view of the lid portion according to the second modification. FIG. 7B is a cross-sectional view showing the configuration of the lid portion according to the second modification. FIG. 7C is a cross-sectional view showing another configuration of the lid portion according to the second modification.

An exemplary embodiment of the present invention will be described below with reference to the drawings.

In the present specification, in the motor 100, the direction parallel to the rotation axis RA is referred to as "axial direction". In the axial direction, the direction from the stator 120 described later to the lid portion 2 described later is referred to as "axially upper side", and the direction from the lid portion 2 toward the stator 120 is referred to as "axially lower side". In each component, the upper end in the axial direction is referred to as the "upper end" and the lower end in the axial direction is referred to as the "lower end". Further, on the surface of each component, the surface facing upward in the axial direction is referred to as "upper surface", and the surface facing downward in the axial direction is referred to as "lower surface".

Further, the direction orthogonal to the rotation axis RA is referred to as a "diameter direction", and the rotation direction centered on the rotation axis RA is referred to as a "circumferential direction". In the radial direction, the direction toward the rotating shaft RA is referred to as "diametrically inside", and the direction away from the rotating shaft RA is referred to as "diametrically outside". In each component, the inner end in the radial direction is referred to as the "inner end" and the outer end in the radial direction is referred to as the "outer end". Further, on the side surface of each component, the side surface facing inward in the radial direction is referred to as an "inner side surface", and the side surface facing outward in the radial direction is referred to as an "outer surface".

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

It should be noted that the names such as the direction, the end portion, and the surface described above do not indicate the positional relationship and the direction when they are 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 aerial vehicle (not shown) to rotate its wings. Not limited to this example, the motor 100 may be mounted on, for example, transportation machines such as automobiles and railways, OA equipment, medical equipment, tools, large-scale industrial 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 2, and a magnet 3. The shaft 111 extends axially along the rotation axis RA and is rotatable about the rotation axis RA. The housing 1 has a tubular shape centered on the rotating shaft RA. The housing 1 internally accommodates the stator 120 and the upper portion of the bearing bush 130. The lid portion 2 is attached to the upper end portion of the housing 1 in the axial direction. A plurality of magnets 3 are arranged on the inner side surface 1a of the housing, and a plurality of magnets 3 are arranged in the circumferential direction on the inner side 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 portion 2 will be described later.

The stator 120 drives and rotates the rotor 110. The stator 120 has a stator core 121 and a coil portion 122. The stator core 121 is an annular shape centered on the rotating shaft RA, and is made of, for example, a laminated steel plate in which a plurality of electromagnetic steel plates are laminated. The coil portion 122 is composed of a conducting wire wound around the stator core 121 via an insulator (not shown).

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

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

The lid portion 2 includes a lid portion opening 2a, a shaft connecting portion 21, an output shaft portion 22, a disk portion 23, a convex portion 24, a balance adjusting member 25, an annular portion 26, and a plurality of ribs 27. It has a wall portion 28 and a plurality of projecting pieces 29.

The lid 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). By doing so, when the rotor 110 rotates, it is possible to generate an air flow through the lid opening 2a between the ribs 27. Further, each rib 27 scratches the air, so that the air flow becomes stronger. Due to such an air flow, the inside of the motor 100 can be effectively cooled by the rotation of the motor 100.

Further, even when the lid portion 2 is attached to the housing 1, the balance adjusting member 25 can be provided on the inner side surface 24a of the convex portion via the lid portion opening 2a.

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

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

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

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

The configuration of the inner side surface 24a of the convex portion is not limited to this example. FIG. 4 is a cross-sectional view of the lid portion 2 showing another configuration example of the inner side surface 24a of the convex portion. As shown in FIG. 4, for example, the convex inner side surface 24a may be an inclined surface that inclines outward in the radial direction toward the lower side in the axial direction. By doing so, the balance adjusting member 25 can be more easily provided on the inner side surface 24a of the convex portion.

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). By doing so, the balance adjusting member 25 can be held on the inner side surface 24a of the convex portion without obstructing the flow of air through the opening 2a of the lid portion.

The balance adjusting member 25 is a member for adjusting the rotational balance of the rotor 110. In the present embodiment, a composite resin material containing a ceramic powder such as alumina is used for the balance adjusting member 25. The balance adjusting member 25 is provided on the inner side surface 24a of the convex portion in the radial direction of the convex portion 24 on the upper side in the axial direction with respect to the stator 120. By doing so, the balance adjusting member 25 is difficult to see from the outside of the lid portion 2. Further, the balance adjusting member 25 is provided on the inner surface surface 24a of the convex portion on the upper side in the axial direction with respect to 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 spoiling the appearance. Although the balance adjusting member 25 is in contact with the lower surface of the disk portion 23 in the present embodiment, the present invention is not limited to this example, and the balance adjusting member 25 may be separated from the lower surface of the disk portion 23. In other words, the balance adjusting member 25 may be provided at a distance from the lower surface of the disk portion 23.

The annular portion 26 is an annular portion centered on the rotation axis RA. The annular portion 26 is located axially above the wall portion 28 and is located axially below the disk portion 23. That is, the annular portion 26 is located between the wall portion 28 and the disk portion 23 in the axial direction. The annular portion 26 connects a plurality of ribs 27 in the circumferential direction.

The rib 27 has a plate shape extending in the axial direction and the radial direction in the present embodiment. 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 less than the number of projecting pieces 29, but is preferably greater than or equal to the number of projecting pieces 29. In other words, the number of ribs 27 is preferably equal to or greater than the number of protrusions 29. If the number is equal to or greater than the number of projecting pieces 29, the air flow through the lid opening 2a can be further strengthened.

The rib 27 extends axially and radially at least axially below the disk portion 23. More specifically, the rib 27 includes the convex plate portion 27a. The convex plate portion 27a extends downward in the axial direction from the lower surface of the disk portion 23, 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 convex plate portion 27a of each rib 27 scratches the air, so that the air flow becomes stronger. Due to such an air flow, the inside of the motor 100 can be effectively cooled by the rotation of the motor 100.

The inner end portion of each rib 27 in the radial direction may be connected to the shaft connecting portion 21 or the output shaft portion 22, but preferably, the shaft connecting portion 21 is at least axially lower than the disk portion 23. Facing each other with an interval 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 done. By doing so, for example, the weight of the motor 100 can be reduced as compared with the configuration in which the inner end portion of each rib 27 is connected to the shaft connecting portion 21. Further, since the material used for forming the rib 27 can be reduced, the cost can be reduced.

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

The wall portion 28 extends axially downward from the annular portion 26 and is located radially inside the housing 1. The wall portion 28 is an annular shape centered on the rotation axis RA and extends in the circumferential direction. The wall portion 28 has a first wall portion 281 and a second wall portion 282.

The first wall portion 281 is in contact with a part of the inner side surface 1a of the housing 1 in the radial direction. The first wall portion 281 has a tubular shape extending in the axial direction. That is, both the inner side surface 1a of the housing and the first outer surface 281a are surfaces extending in the axial direction. By doing so, the contact area where the first wall portion 281 is in contact with the inner side surface of the housing 1 becomes wider, so that the mounting strength between the first wall portion 281 and the housing 1 is improved.

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

In the present embodiment, the second wall portion 282 is 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 centered on the rotation axis RA. Alternatively, there may be a plurality of second wall portions 282, and each of the second wall portions 282 may be arranged at 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 the second outer surface 282a of the second wall portion 282 as shown in FIG. It is larger than the second radial distance L2 with the rotation axis RA. In this way, the lid portion 2 is provided with a portion where the first wall portion 281 is in contact with the inner side surface 1a of the housing and a portion where the second wall portion 282 is adhered to the inner side surface 1a of the housing by the adhesive 28a. As a result, the load applied between the housing 1 and the lid portion 2 when the rotor 110 rotates can be distributed to each portion. Therefore, it is possible to prevent a gap from being formed between the upper end portion of the housing 1 in the axial direction and the lid portion 2.

Specifically, when the lid 2 is attached to the housing 1, the first wall 281 has a more tight housing than, for example, a configuration in which the lid 2 is attached to the housing 1 only by adhesion using an adhesive 28a. While in contact with the inner side surface 1a, it is guided downward in the axial direction along the inner side surface 1a of the housing. Therefore, the lid portion 2 can be more easily attached to the housing 1 while suppressing the formation of a gap between the wall portion 28 and the housing 1. Further, the mounting angle between the direction in which the wall portion 28 extends and the direction in which the housing 1 extends is less likely to deviate. Further, the mounting position of the lid 2 with respect to the housing 1 in the radial direction is less likely to shift. Therefore, the accuracy of attaching the lid 2 to the housing 1 can be improved. Therefore, it is possible to improve the balance accuracy of the rotor 110 during rotation.

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. 5, the second wall portion 282. It is smaller than the axial length D2. When D1 <D2 is set in this way, for example, the safety factor of the load stress with respect to the proof stress of the wall portion 28 is improved as compared with the structure in which the lid portion 2 is attached to the housing 1 only by the contact between the wall portion 28 and the housing 1. .. 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 projecting piece 29 projects downward in the axial direction from the lower end portion of the wall portion 28 in the axial direction. More specifically, the projecting pieces 29 project downward from the lower end portion in the axial direction of the second wall portion 282 in the axial direction, and a plurality of the projecting pieces 29 are arranged in the circumferential direction. Each projecting piece 29 is arranged between adjacent magnets 3. By doing so, the magnet 3 can be positioned in the circumferential direction and the axial direction. Further, the projecting piece 29 extends from the lower end portion of the second wall portion 282, which is difficult to apply a load. Therefore, the accuracy of the position of the magnet 3 in the circumferential direction and the axial direction can be improved.

The number of projecting 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, the magnet 3 can be easily attached to the housing 1.

Further, in each projecting piece 29, at least a part of the projecting piece 29 overlaps with the rib 27 when viewed from the axial direction. This makes it easier to mold the lid portion 2 using, for example, a mold.

<2. Deformation example of the lid>
Next, first and second modification examples of the lid portion 2 will be described. In the following description, a configuration different from the above-described embodiment will be mainly described. Further, in each modification, the same components as those of the above-described embodiment and other modifications may be designated by the same reference numerals, and the description of the same configuration as that of the above-described embodiment and other modifications may be omitted.

<2-1. First modification>
FIG. 6A is a perspective view of the motor 100 showing a first modification of the lid portion 2. FIG. 6B is a cross-sectional view showing the configuration of the lid portion 2 according to the first modification.

As shown in FIGS. 6A and 6B, the lid portion 2 according to the first modification includes a lid portion opening 2a, a shaft connecting portion 21, an output shaft portion 22, a disk portion 23, and an annular portion 26. It has a rib 27, a wall portion 28, and a plurality of projecting pieces 29. On the other hand, in the first modification, the lid portion 2 does not have the convex portion 24 of the above-described embodiment, and each rib 27 does not have the convex plate portion 27a of the above-described embodiment. By doing so, for example, the weight of the motor 100 can be reduced as compared with a configuration in which each rib 27 has a convex plate portion 27a. Further, since the material used for forming the rib 27 can be reduced, the cost can be reduced.

When viewed from the axial direction, at least one end of the rib 27 in the circumferential direction is recessed from the outside to the inside of the rib 27 in the circumferential direction. For example, in FIG. 6A, when viewed from the axial direction, the end portion of the rib 27 on one side in the circumferential direction is recessed from one side in the circumferential direction toward the other side in the circumferential direction, and the end portion of the rib 27 on the other side in the circumferential direction is in the circumferential direction. It dents from the other side toward one side in the circumferential direction. By doing so, the width in the circumferential direction of the lid opening 2a becomes wider, so that more air flows through the lid opening 2a. Therefore, the cooling efficiency of the motor 100 is improved.

Further, the radial width of the disk portion 23 in FIG. 6 is narrower than the radial width of the disk portion 23 in the above-described embodiment (see FIG. 2 and the like). In other words. The radial width of the lid opening 2a is wider than that of the above-described embodiment. By doing so, the cooling efficiency of the motor 100 is further improved.

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

As shown in FIGS. 7A to 7C, the lid portion 2 according to the second modification has a lid portion opening 2a, a shaft connecting portion 21, an output shaft portion 22, a disk portion 23, and a convex portion 24, and is balanced. It has an adjusting member 25, an annular portion 26, a plurality of ribs 27, a wall portion 28, and a plurality of projecting pieces 29. On the other hand, in the second modification, each rib 27 does not include the convex plate portion 27a of the above-described embodiment. By doing so, for example, the weight of the motor 100 can be reduced as compared with the configuration in which each rib 27 includes the convex plate portion 27a. Further, since the material used for forming the rib 27 can be reduced, the cost can be reduced. In addition, the internal space of the lid portion 2 becomes wider.

The disk portion 23 has a plate portion 231, a ring portion 232, and an upper opening 233. The plate portion 231 extends radially outward from the outer surface of the shaft connecting portion 21, and is located radially inside the ring portion 232. The ring portion 232 is an annular shape centered on the rotation shaft RA, and is radially connected to the plate portion 231 by a plurality of ribs 27. In the axial direction, the ring portion 232 is located below the plate portion 231 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. By doing so, air passes between the outside and the inside of the lid portion 2 through the upper opening 233, so that the inside of the motor 100 can be further cooled easily.

The convex portion 24 protrudes downward in the axial direction from the ring portion 232. A balance adjusting member 25 is provided on the inner side surface 24a 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 is preferably in contact with the lower surface of the ring portion 232.

As shown in FIG. 7B, the inner side surface 24a of the convex portion in the radial direction of the convex portion 24 may be parallel to the rotation axis RA. By doing so, when the rotor 110 is rotated, the balance adjusting member 25 is held on the two surfaces of the convex inner side surface 24a and the lower surface of the ring portion 232, so that the balance adjusting member 25 can be stably moved to the convex inner side surface 24a. Can be held in.

Alternatively, as shown in FIG. 7C, the convex inner side surface 24a may be an inclined surface that inclines outward in the radial direction toward the lower side in the axial direction. By doing so, the balance adjusting member 25 can be more easily provided on the inner side surface 24a of the convex portion.

<3. Others>
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 carried out with various modifications without departing from the gist of the invention. In addition, the matters described in the above-described embodiments can be arbitrarily combined as long as they do not cause a contradiction.

INDUSTRIAL APPLICABILITY The present invention can be used for a motor in which a lid portion is attached to an end portion on one side in the axial direction of the housing.

100 ... motor, 110 ... rotor, 111 ... shaft, 1 ... housing, 1a ... housing inner surface, 2 ... lid, 2a ... lid opening, 21 ...・ Shaft connection part, 21a ・ ・ ・ Mounting hole, 22 ・ ・ ・ Output shaft part, 23 ・ ・ ・ Disk part, 231 ・ ・ ・ Plate part, 232 ・ ・ ・ Ring part, 233 ・ ・ ・ Upper opening, 24 ・.. Convex part, 24a ... Convex part inner surface, 25 ... Balance adjusting member, 26 ... Circular part, 27 ... Rib, 27a ... Convex plate part, 28 ... Wall part, 28a ... adhesive, 281 ... first wall portion, 281a ... first outer surface, 282 ... second wall portion, 282a ... second outer surface, 29 ... projecting piece, 3 ... Magnet, 120 ... Stator, 121 ... Stator core, 122 ... Coil part, 130 ... Bearing bush, 131a, 131b ... Bearing, RA ... Rotating shaft, L1 ... 1st radial distance, L2 ... 2nd radial distance, D1, D2 ... axial length, W1 ... 1st axial distance, W2 ... 2nd axial distance

Claims (9)

A rotor that can rotate around the axis of rotation and
The stator that drives the rotor and
Equipped with
The rotor is
With a cylindrical housing,
A lid attached to the upper end of the housing in the axial direction,
Have,
The lid portion has a wall portion located radially inside the housing and extending circumferentially.
The wall is
A first wall portion in contact with a part of the inner side surface of the housing in the radial direction of the housing,
The second wall portion extending downward in the axial direction from the lower end portion in the axial direction of the first wall portion, and the second wall portion.
Have,
The first radial distance between the first outer surface of the first wall and the rotating shaft is the second radial distance between the second outer surface of the second wall and the rotating shaft. Greater than
The second outer surface faces the inner side surface of the housing via an adhesive , the rotor has a magnet, and the adhesive material is a motor in contact with the magnet .
The motor according to claim 1, wherein the first wall portion has a tubular shape extending in the axial direction. The motor according to claim 1 or 2, wherein the axial length of the first wall portion is smaller than the axial length of the second wall portion. The lid is
A disk portion centered on the rotation axis and extending in the radial direction,
An annular portion located above the wall portion in the axial direction and below the disc portion in the axial direction and centered on the rotation axis.
A plurality of ribs that connect between the disk portion and the annular portion, extend in the axial and radial directions, and are lined up in the circumferential direction.
A lid opening provided between the ribs and between the disk portion and the annular portion,
The motor according to any one of claims 1 to 3. The rotor further comprises a shaft that extends axially along the axis of rotation and is rotatable about the axis of rotation.
The lid portion further has a shaft connecting portion that is connected to the shaft.
The motor according to claim 4, wherein the inner end portion of each of the ribs in the radial direction faces the shaft connecting portion with a radial distance at least on the lower side in the axial direction from the disk portion. The rotor further has a plurality of magnets arranged on the inner side surface of the housing and arranged in the circumferential direction.
The lid portion further has a plurality of projecting pieces that project downward in the axial direction from the lower end portion in the axial direction of the second wall portion and are lined up in the circumferential direction.
The motor according to claim 4 or 5, wherein the projecting piece is arranged between adjacent magnets. The motor according to claim 6, wherein the number of ribs is equal to or greater than the number of protruding pieces. The motor according to claim 6 or 7, wherein the number of magnets is the same as the number of protruding pieces. The motor according to claim 7 or 8, wherein at least a part of the protruding piece overlaps with the rib when viewed from the axial direction.

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