JP6830343B2 - Rotor and motor - Google Patents

Description

The present invention relates to a rotor in which a rotor magnet is fixed to a rotating shaft via a bush, and a motor including the rotor.

The rotor used in the motor is provided with a rotor magnet around a rotating shaft (see Patent Document 1). When constructing such a rotor, in the case of a structure in which the rotating shaft is inserted into the center hole of the cylindrical rotor magnet, the volume of the rotor magnet is large, so that there are drawbacks that the cost of the rotor magnet increases and the rotor becomes heavy. ing. Therefore, a structure has been proposed in which the outer peripheral edge of the bush in which the rotating shaft is press-fitted into the center hole is fixed to the inner peripheral surface of a cylindrical rotor magnet with an adhesive (see Patent Document 2). According to such a structure, since the space between the rotating shaft and the rotor magnet can be made hollow, the weight of the rotor can be reduced and the volume of the rotor magnet can be reduced. Further, Patent Document 2 proposes that a step portion is formed on the outer peripheral edge of the bush, and the bush and the rotor magnet are securely fixed by forming a pool portion of the adhesive by the step portion. ..

Japanese Unexamined Patent Publication No. 2014-212686 Japanese Unexamined Patent Publication No. 2000-78824

In the motor described in Patent Document 2, in order to provide a sufficient amount of adhesive, it is necessary to make the pooled portion of the adhesive sufficiently large. However, in a structure in which an adhesive pool is formed by a step formed on the outer peripheral edge of a bush like the motor described in Patent Document 2, the step portion is required to have a sufficiently large adhesive pool. It is necessary to have a structure in which a wide step portion is formed or a structure in which a step portion is formed deeply. However, depending on the thickness of the bush and the like, the optimum step portion may not be provided on the outer peripheral edge of the bush.

In view of the above problems, the subject of the present invention is a rotor and a motor capable of providing an appropriate amount of adhesive between the bush for fixing the rotor magnet to the rotating shaft and the inner peripheral surface of the rotor magnet. Is to provide.

In order to solve the above problems, in the rotor according to the present invention, a rotating shaft, a cylindrical rotor magnet arranged coaxially with the rotating shaft around the rotating shaft, and the rotating shaft are press-fitted. It has a bush having a central hole and an outer peripheral edge fixed to the inner peripheral surface of the rotor magnet by an adhesive, and an end surface of the bush facing outward in the axial direction of the rotation axis is from the outer peripheral edge. A step portion recessed inward in the axial direction is formed so as to extend in the circumferential direction at a position separated inward in the radial direction, and the adhesive is applied to the edge of the step portion and the inner peripheral surface of the rotor magnet. The bush and the rotor magnet are adhesively fixed to each other, and the edge of the step portion is a radial outer opening edge of a groove-shaped recess extending in the circumferential direction on the end face. It is characterized by that.

In the present invention, since the space between the rotating shaft and the rotor magnet can be made hollow, the weight of the rotor can be reduced and the volume of the rotor magnet can be reduced. Further, on the end face facing outward in the axial direction of the bush, a step portion is provided at a position radially inward from the outer peripheral edge, so that an adhesive is provided between the edge of the step portion and the inner peripheral surface of the rotor magnet. Even if the adhesive tries to flow out radially inward when the above is arranged, the adhesive is unlikely to flow out radially inward from the edge of the step due to the influence of surface tension. Therefore, a sufficient amount of adhesive can be provided between the edge of the step portion and the inner peripheral surface of the rotor magnet, so that the bush and the rotor magnet can be firmly adhered to each other. Further, since the amount of adhesive accumulated can be controlled by the distance from the inner peripheral surface of the rotor magnet to the edge of the step portion, the amount of adhesive accumulated is not easily affected by the height difference of the step portion and the like. Therefore, when a sufficient amount of adhesive is stored between the edge of the step portion and the inner peripheral surface of the rotor magnet, the distance from the inner peripheral surface of the rotor magnet to the edge of the step portion may be increased. Even when an appropriate amount of adhesive is provided, it is easy to process the bush.

The inner surface of the recess may adopt an aspect having water repellency. According to such an aspect, even when the adhesive flows out into the recess, it is possible to prevent the adhesive from flowing out radially inward from the recess.

In the present invention, the bush can adopt a plate-like aspect.

In the present invention, it is possible to adopt an embodiment in which the bush is formed with a through hole penetrating in the axial direction. According to this aspect, the space surrounded by the rotor magnet and the bush with the rotor magnet fixed to the rotating shaft by the bush communicates with the outside through the through hole of the bush. Therefore, even if the ambient temperature or the like changes and the air in the space surrounded by the rotor magnet and the bush expands or contracts, it is possible to suppress the peeling of the adhesive due to the bush moving in the axial direction. it can.

In the present invention, it is possible to adopt an embodiment in which the bush is provided at two locations separated in the axial direction. According to such an embodiment, the rotating shaft and the data magnet can be securely fixed by the bush having a simple structure.

The motor provided with the rotor according to the present invention has a stator facing the rotor magnet on the outer side in the radial direction.

In the present invention, since the space between the rotating shaft and the rotor magnet can be made hollow, the weight of the rotor can be reduced and the volume of the rotor magnet can be reduced. Further, on the end face facing outward in the axial direction of the bush, a step portion is provided at a position radially inward from the outer peripheral edge, so that an adhesive is provided between the edge of the step portion and the inner peripheral surface of the rotor magnet. Even if the adhesive tries to flow out radially inward when the above is arranged, the adhesive is unlikely to flow out radially inward from the edge of the step due to the influence of surface tension. Therefore, a sufficient amount of adhesive can be provided between the edge of the step portion and the inner peripheral surface of the rotor magnet, so that the bush and the rotor magnet can be firmly adhered to each other. Further, since the amount of adhesive accumulated can be controlled by the distance from the inner peripheral surface of the rotor magnet to the edge of the step portion, the amount of adhesive accumulated is not easily affected by the height difference of the step portion and the like. Therefore, when a sufficient amount of adhesive is stored between the edge of the step portion and the inner peripheral surface of the rotor magnet, the distance from the inner peripheral surface of the rotor magnet to the edge of the step portion may be increased. Even when an appropriate amount of adhesive is provided, it is easy to process the bush.

It is sectional drawing of the motor to which this invention was applied. It is sectional drawing of the rotor used for the motor shown in FIG. It is explanatory drawing when the bush used for the rotor shown in FIG. 2 is seen from the axial direction. It is explanatory drawing which enlarges and shows the adhesive part between the bush (the first bush and the second bush) and a rotor magnet in the rotor shown in FIG.

A rotor and a motor to which the present invention is applied will be described with reference to the drawings. In the motor 1 described below, the rotation center axis of the rotation shaft 12 is defined as the axis L, and the direction in which the rotation center axis of the rotation shaft 12 extends is defined as the axis L direction. Further, one side on which the rotating shaft 12 protrudes is referred to as an output side L1, and the side opposite to the side on which the rotating shaft 12 protrudes (the other side) is referred to as a counter-output side L2.

(overall structure)
FIG. 1 is a cross-sectional view of a motor to which the present invention is applied. The motor 1 shown in FIG. 1 is a stepping motor 1a, and has a rotor 10 having a rotor magnet 11 on the radial outer side of the rotating shaft 12, and a tubular stator 20 facing the outer peripheral surface of the rotor magnet 11. ing. On the outer peripheral surface of the rotor magnet 11, north poles and south poles are alternately arranged in the circumferential direction.

The stator 20 has a pair of stator sets 21 and 22 arranged so as to overlap in the axis L direction, and the stator sets 21 and 22 have insulators 216 and 226 and coils wound around insulators 216 and 226, respectively. It includes 213 and 223, and stator cores 211 and 212 and stator cores 221 and 222 arranged on both sides of the insulators 216 and 226 in the L direction of the axis. The stator core 211 is an outer stator core that covers the surface of the output side L1 of the insulator 216, and the stator core 212 is an inner stator core that covers the surface of the insulator 216 on the opposite output side L2. The stator core 221 is an outer stator core that covers the surface of the insulator 226 on the opposite output side L2, and the stator core 222 is an inner stator core that covers the surface of the insulator 226 on the output side L1. The stator cores 211 and 221 have a U-shaped cross section, and the motor case is formed by a tubular portion on the outer peripheral side.

The stator cores 211, 212, 221 and 222 each include a plurality of pole teeth 217 and 227 that stand up along the inner peripheral surface of the insulators 216 and 226. The polar teeth 217 formed on the stator core 211 in the state of forming the stator assembly 21 entered between the polar teeth 217 formed on the stator core 212, and were formed on the polar teeth 217 and the stator core 212 formed on the stator core 211. The polar teeth 217 are arranged alternately in the circumferential direction. Further, in the state where the stator assembly 22 is configured, the polar teeth 227 formed on the stator core 221 enter between the polar teeth 227 formed on the stator core 222 and are formed on the polar teeth 227 and the stator core 222 formed on the stator core 221. The pole teeth 227 are arranged alternately in the circumferential direction.

Terminal blocks 218 and 228 are integrally formed on the insulators 216 and 226, and terminals 219 and 229 are fixed to the terminal blocks 218 and 228. Of both end faces of the stator 20, the output side end plate 25 is fixed to the end portion 23 of the output side L1, and the anti-output side end plate 26 is fixed to the end portion 24 of the anti-output side L2.

In this embodiment, the output side radial bearing 7 that rotatably supports the rotary shaft 12 on the output side L1 by using the output side end plate 25 is held. More specifically, a hole 251 is formed in the output side end plate 25, and the output side radial bearing 7 is held in the output side end plate 25 in a state of being fitted in the hole 251. The output side radial bearing 7 has a tubular portion 71 fitted in the hole 251 and a flange portion 72 having a diameter larger than that of the tubular portion 71 by expanding the diameter of the tubular portion 71 on the output side L1. The output side radial bearing 7 is made of a sintered oil-impregnated bearing or the like. Further, the anti-output side radial bearing 8 that rotatably supports the rotating shaft 12 on the anti-output side L2 by using the anti-output side end plate 26 is held. More specifically, a hole 261 is formed in the counter-output side end plate 26, and the counter-output side radial bearing 8 is held in the counter-output side end plate 26 in a state of being fitted in the hole 261. The non-output side radial bearing 8 has a tubular portion 81 fitted in the hole 261 and a flange portion 82 having a diameter larger than that of the tubular portion 81 by expanding the diameter of the tubular portion 81 on the output side L1. The radial bearing 8 on the non-output side is made of a sintered oil-impregnated bearing.

In the motor 1, an annular washer 41 through which the rotating shaft 12 penetrates is arranged between the output side radial bearing 7 and the rotor 10. Further, between the radial bearing 8 on the counter-output side and the rotor 10, an annular washer 42, an annular washer 42 composed of an annular disc spring, a coil spring, or the like, and an annular member 43 from the counter-output side L2 to the output side L1. The washer 44 is arranged, and the rotor 10 is urged toward the output side L1 by the urging member 43.

(Structure of rotor 10)
FIG. 2 is a cross-sectional view of the rotor 10 used in the motor 1 shown in FIG. FIG. 3 is an explanatory view of the first bush 14 and the like used for the rotor 10 shown in FIG. 2 when viewed from the axis L direction. FIG. 4 is an enlarged explanatory view showing an enlarged bonding portion between the bushes (first bush 14 and second bush 15) and the rotor magnet 11 in the rotor 10 shown in FIG. In FIG. 3, reference numerals are given in parentheses for the portions of the second bush 15 corresponding to the respective portions of the first bush 14.

As shown in FIG. 2, the rotor 10 includes a rotating shaft 12, a cylindrical rotor magnet 11 that is coaxially arranged around the rotating shaft 12 with respect to the rotating shaft 12, and a rotating shaft 12 and a rotor magnet 11. It has two bushes (first bush 14 and second bush 15) for connecting the two bushes. Both the first bush 14 and the second bush 15 are made of an iron-based metal plate having a thickness of about 1.2 mm.

As shown in FIGS. 2, 3 and 4, the first bush 14 is a circular plate-shaped member having a center hole 140 into which the rotating shaft 12 is press-fitted, and the outer peripheral edge 148 is the inner circumference of the rotor magnet 11. It is fixed to the surface 110 by the adhesive 18. More specifically, the first bush 14 is arranged at a position retracted from the end 111 of the output side L1 of the rotor magnet 11 to the opposite output side L2, and the adhesive 18 is located on the output side of the first bush 14. It is provided so as to be in contact with both the outer peripheral portion 143 of the end surface 141 of L1 and the inner peripheral surface 110 of the rotor magnet 11, and the outer peripheral edge 148 of the first bush 14 and the inner peripheral surface 110 of the rotor magnet 11 are adhered and fixed. There is. In this embodiment, the adhesive 18 is an ultraviolet curable adhesive.

The outer diameter of the first bush 14 is smaller than the inner diameter of the rotor magnet 11. Therefore, there is a gap 144 between the outer peripheral edge 148 of the first bush 14 and the inner peripheral surface 110 of the rotor magnet 11. Therefore, a part of the adhesive 18 penetrates into the gap 144 and adheres the first bush 14 and the rotor magnet 11.

Like the first bush 14, the second bush 15 is a circular plate-shaped member having a center hole 150 into which the rotating shaft 12 is press-fitted, and the outer peripheral edge 158 is an adhesive 19 on the inner peripheral surface 110 of the rotor magnet 11. Is fixed by. More specifically, the second bush 15 is arranged at a position retracted from the end 112 of the counter-output side L2 of the rotor magnet 11 to the output side L1, and the adhesive 19 is the counter-output of the second bush 15. It is provided so as to be in contact with both the outer peripheral portion 153 of the end surface 151 of the side L2 and the inner peripheral surface 110 of the rotor magnet 11, and the outer peripheral edge 158 of the second bush 15 and the inner peripheral surface 110 of the rotor magnet 11 are adhesively fixed. ing. In this embodiment, the adhesive 19 is an ultraviolet curable adhesive.

The outer diameter of the second bush 15 is smaller than the inner diameter of the rotor magnet 11. Therefore, there is a gap 154 between the outer peripheral edge 158 of the second bush 15 and the inner peripheral surface 110 of the rotor magnet 11. Therefore, a part of the adhesive 19 penetrates into the gap 154 and adheres the second bush 15 and the rotor magnet 11.

In this embodiment, through holes 142 and 152 are formed in the first bush 14 and the second bush 15. Therefore, the space surrounded by the rotor magnet 11, the first bush 14, and the second bush 15 with the rotor magnet 11 fixed to the rotating shaft 12 by the first bush 14 and the second bush 15 is the first bush. It communicates with the outside through the through holes 142 and 152 of the 14 and the second bush 15. Therefore, even if the ambient temperature or the like changes and the air in the space surrounded by the rotor magnet 11, the first bush 14 and the second bush 15 expands or contracts, the first bush 14 and the second bush 15 remain on the axis. It is difficult to move in the L direction.

(Adhesive structure of the first bush 14 and the second bush 15 with the rotor magnet 11)
As shown in FIGS. 3 and 4, the end surface 141 (the end surface of the output side L1) of the rotating shaft 12 facing outward in the axis L direction of the rotating shaft 12 is located at a position radially inward from the outer peripheral edge 148. A step portion 146 recessed toward the inside (reverse output side L2) in the axis L direction is formed, and the step portion 146 extends in the circumferential direction. The adhesive 18 is held between the edge 146a of the step portion 146 and the inner peripheral surface 110 of the rotor magnet 11 to bond and fix the first bush 14 and the rotor magnet 11. In this embodiment, when the adhesive 18 is applied so as to be in contact with the outer peripheral portion 143 including the outer peripheral edge 148 of the first bush 14 and the inner peripheral surface 110 of the rotor magnet 11, the adhesive 18 is indicated by an arrow R18. Even when the adhesive 18 tries to flow inward in the radial direction, the adhesive 18 is less likely to flow out inward in the radial direction than the step portion 146 due to the influence of surface tension. That is, the space between the edge 146a of the step portion 146 and the inner peripheral surface 110 of the rotor magnet 11 serves as a pool portion of the adhesive 18, and the first bush 14 and the rotor magnet 11 are fixed by the adhesive 18.

In this embodiment, the end surface 141 of the first bush 14 (the end surface of the output side L1) has a groove recessed toward the inside in the axis L direction (anti-output side L2) at a position separated radially inward from the outer peripheral edge 148. A shaped recess 145 is formed, and the step portion 146 is formed by an opening edge located on the radial outer side of the recess 145. The recess 145 is formed in an annular shape connecting in the circumferential direction. Therefore, the step portion 146 is formed in an annular shape connecting in the circumferential direction.

Further, the second bush 15 side has the same structure as the first bush 14 side. Specifically, in the second bush 15, the end surface 151 (the end surface of the counter-output side L2) of the rotating shaft 12 facing outward in the axis L direction is located at a position radially inward away from the outer peripheral edge 158 in the axis L direction. A step portion 156 that is recessed toward the inside (output side L1) is formed, and the step portion 156 extends in the circumferential direction. The adhesive 19 is held between the edge 156a of the step portion 156 and the inner peripheral surface 110 of the rotor magnet 11 to bond and fix the second bush 15 and the rotor magnet 11. In this embodiment, when the adhesive 19 is applied so as to be in contact with the outer peripheral portion 153 including the outer peripheral edge 158 of the second bush 15 and the inner peripheral surface 110 of the rotor magnet 11, the adhesive 19 is indicated by an arrow R19. Even when the adhesive 19 tries to flow inward in the radial direction, the adhesive 19 is less likely to flow out inward in the radial direction than the step portion 156 due to the influence of surface tension. That is, the space between the edge 156a of the step portion 156 and the inner peripheral surface 110 of the rotor magnet 11 serves as a pool portion of the adhesive 19, and the second bush 15 and the rotor magnet 11 are fixed by the adhesive 18.

In the present embodiment, the end surface 151 of the second bush 15 (the end surface of the counter-output side L2) has a groove recessed toward the inside in the axis L direction (output side L1) at a position separated radially inward from the outer peripheral edge 158. A shaped recess 155 is formed, and the step portion 156 is formed by an opening edge located on the radial outer side of the recess 155. The recess 155 is formed in an annular shape connecting in the circumferential direction. Therefore, the step portion 156 is formed in an annular shape connecting in the circumferential direction.

(Main effect of this form)
As described above, in the motor 1 of the present embodiment, since the space between the rotating shaft 12 and the rotor magnet 11 can be made hollow, the weight of the rotor 10 can be reduced and the volume of the rotor magnet 11 can be reduced. It can be made smaller.

Further, in fixing the rotating shaft 12 and the rotor magnet 11, a part of the adhesive 18 penetrates into the gap 144 between the outer peripheral edge 148 of the first bush 14 and the inner peripheral surface 110 of the rotor magnet 11. , The first bush 14 and the rotor magnet 11 are adhered to each other. Similarly, a part of the adhesive 19 penetrates into the gap 154 between the outer peripheral edge 158 of the second bush 15 and the inner peripheral surface 110 of the rotor magnet 11, and adheres the second bush 15 and the rotor magnet 11. To do. Further, on the end faces 141 and 151 of the first bush 14 and the second bush 15 facing outward in the axis L direction, the step portions 146 and 156 are provided at positions separated radially inward from the outer peripheral edges 148 and 158. When the adhesives 18 and 19 are arranged between the edges 146a and 156a of the step portions 146 and 156 and the inner peripheral surface of the rotor magnet 11, the adhesives 18 and 19 are affected by the surface tension of the step portions 146 and 156. It is difficult for the edges 146a and 156a to flow inward in the radial direction. Therefore, a sufficient amount of adhesives 18 and 19 can be provided between the edges 146a and 156a of the step portions 146 and 156 and the inner peripheral surface 110 of the rotor magnet 11, so that the first bush 14 and the second bush 15 can be provided. And the rotor magnet 11 can be firmly adhered to each other. At that time, the amount of the adhesives 18 and 19 accumulated can be controlled by the distance from the inner peripheral surface 110 of the rotor magnet 11 to the edges 146a and 156a of the step portions 146 and 156, so that the amount of the adhesives 18 and 19 accumulated can be controlled. Is not easily affected by the height difference of the step portions 146 and 156. Therefore, when a sufficient amount of adhesive is stored between the edges 146a and 156a of the step portions 146 and 156 and the inner peripheral surface 110 of the rotor magnet 11, the step portion 146 is formed from the inner peripheral surface 110 of the rotor magnet 11. Even when an appropriate amount of adhesive is provided, such as increasing the distance to the edges 146a and 156a of 156, the first bush 14 and the second bush 15 can be easily processed.

Further, since the adhesives 18 and 19 are ultraviolet curable adhesives, they are less likely to flow out radially inward from the edges 146a and 156a of the step portions 146 and 156 as compared with the case where the thermosetting adhesive is used. That is, in the case of a heat-curable adhesive, when the curing reaction is started by heating, the surface tension tends to decrease until the temperature of the adhesive itself rises and the curing reaction occurs. Therefore, the adhesive is determined by the surface tension. Although it is difficult to hold it in place, if it is an ultraviolet curable adhesive, it is unlikely that the surface tension will decrease before curing.

Further, in the present embodiment, since the first bush 14 and the second bush 15 are provided at two positions separated in the axis L direction, the rotating shaft is provided by the first bush 14 and the second bush 15 having a simple structure. 12 and the rotor magnet 11 can be securely fixed.

Furthermore, since the first bush 14 and the second bush 15 are formed with through holes 142 and 152, the ambient temperature and the like change, and the first bush 14 and the second bush 15 are surrounded by the rotor magnet 11, the first bush 14, and the second bush 15. Even if the air in the space expands or contracts, the first bush 14 and the second bush 15 do not easily move in the L direction of the axis. Therefore, peeling of the adhesives 18 and 19 is unlikely to occur.

(Other embodiments)
In the above embodiment, the inner surface of the recesses 145 and 155 may be subjected to a water repellent treatment using a fluorine-based water repellent or the like to impart water repellency to the inner surfaces of the recesses 145 and 155. According to such a configuration, even when the adhesives 18 and 19 flow out to the inside of the recesses 145 and 155, it is possible to prevent the adhesives 18 and 19 from flowing out to the inside of the recesses 145 and 155 in the radial direction.

In the above embodiment, the present invention is applied to both the first bush 14 and the second bush 15, but the present invention may be applied to only one bush.

In the above embodiment, the rotor magnet 11 is connected to the rotating shaft 12 by using two bushes (first bush 14 and second bush 15), but the bottom plate portion of one cup-shaped bush is fixed to the rotating shaft 12. The present invention may be applied when the rotor magnet 11 is fixed to the outer peripheral side of the cylinder portion with an adhesive.

In the above embodiment, the radial outer opening edges of the groove-shaped recesses 145 and 155 are used as the step portions 146 and 156, but the first bush has a flat portion radially inside from the step portions 146 and 156. A mode in which the rotor magnet 11 is fixed to the 14 and the second bush 15 by the adhesives 18 and 19 may be adopted.

In the above embodiment, the step portions 146 and 156 are at right angles, but an embodiment in which the corners are chamfered curved surfaces may be adopted. In the above embodiment, the recesses 145 and 155 are groove-shaped with a rectangular cross section, but may be a groove with a V-shaped cross section.

In the above embodiment, the ultraviolet curable adhesive is used as the adhesives 18 and 19, but a thermosetting adhesive may be used. Further, as the adhesives 18 and 19, thermosetting adhesives imparted with ultraviolet curability may be used. In this case, after temporary curing by ultraviolet irradiation, main curing by heating can be performed. It is possible to prevent the adhesive from flowing out inward in the radial direction during the heating of the main curing.

1 ... motor, 1a ... stepping motor, 10 ... rotor, 11 ... rotor magnet, 12 ... rotating shaft, 14 ... first bush, 15 ... second bush, 18, 19 ... adhesive, 20 ... stator, 141, 151 ... End face, 140, 150 ... Center hole, 142, 152 ... Through hole, 143, 153 ... Outer peripheral part, 144, 154 ... Gap, 145, 155 ... Recessed part, 146, 156 ... Step part, 146a, 156a ... Edge, 148 , 158 ... outer peripheral edge, L ... axis, L1 ... output side, L2 ... anti-output side

Claims (6)

The axis of rotation and
A cylindrical rotor magnet arranged coaxially with the rotating shaft around the rotating shaft,
A bush having a central hole into which the rotating shaft is press-fitted and having an outer peripheral edge fixed to the inner peripheral surface of the rotor magnet with an adhesive.
Have,
On the end surface of the bush facing outward in the axial direction of the rotation axis, a step portion recessed inward in the axial direction extends in the circumferential direction at a position separated radially inward from the outer peripheral edge. Formed,
The adhesive is held between the edge of the step portion and the inner peripheral surface of the rotor magnet to bond and fix the bush and the rotor magnet .
The rotor is characterized in that the edge of the step portion is a radial outer opening edge of a groove-shaped recess extending in the circumferential direction on the end face . The rotor according to claim 1 , wherein the inner surface of the recess has water repellency. The rotor according to claim 1 or 2 , wherein the bush has a plate shape. The rotor according to any one of claims 1 to 3 , wherein the bush is formed with a through hole penetrating in the axial direction. The rotor according to any one of claims 1 to 4 , wherein the bushes are provided at two locations separated in the axial direction. A motor according to any one of claims 1 to 5 , wherein the motor has a stator facing the rotor magnet on the outer side in the radial direction.

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