Motor

Abstract

For example, the coaxiality of a motor is increased. A motor (100) includes, for example, a shaft (S), a magnet (112, 212), a coil (120), a first bearing (113a) arranged at one end portion (S1) of the shaft (S) in an axial direction, a second bearing (113b) arranged at the other end portion (S2) of the shaft (S) in the axial direction, a cover (114, 414) fixed to the second bearing (113b) and arranged inside the coil (120) in a radial direction, a holder (115, 415) fixed to the first bearing (113a), and an elastic member (116, 416) held by the holder (115, 415). The elastic element (116, 416) is arranged between the cover (114, 414) and the holder (115, 415) in a longitudinal direction of the shaft (S).

Description

TECHNICAL FIELD

[0001] The present invention relates to an engine. STATE OF THE ART

[0002] Conventionally, a motor is known that includes a bearing device provided with bearings at both ends of a shaft. In the bearing device, the two bearings are preloaded in directions away from each other in an axial direction. For example, Patent Document 1 discloses a rolling bearing device including a preload unit including an elastic member. Literature listPatent literature

[0003] Patent Document 1: JP 04-82425 UM-A Brief description of the inventionTechnical problem

[0004] In this type of motor, the coaxiality of a rotor and a stator must be increased.

[0005] An example of an object of the present invention is to increase the coaxiality of a motor. Solution to the problem

[0006] A motor according to the present invention includes a shaft, a magnet, a coil, a first bearing disposed on one side of one end portion of the shaft in an axial direction, a second bearing disposed on one side of the other end portion of the shaft in the axial direction, a cover fixed to the second bearing and disposed inside the coil in a radial direction, a holder fixed to the first bearing, and an elastic member held by the holder. The elastic member is disposed between the cover and the holder in a longitudinal direction of the shaft.

[0007] Another motor according to the present invention includes an annular yoke including two end surfaces in an axial direction. This motor further includes a stator including a plurality of magnetic pole pieces, a plurality of spokes coupled to the plurality of magnetic pole pieces and an inner peripheral portion of the annular yoke, and a plurality of coils wound around the plurality of spokes. In this motor, each of the plurality of spokes is attachable to and detachable from the annular yoke, the annular yoke and each of the plurality of spokes are formed of a plurality of magnetic bodies stacked in the axial direction, and the plurality of magnetic bodies constituting the spokes are biased from one side of one end surface to one side of the other of the two end surfaces of the annular yoke.

[0008] Another engine according to the present invention may further include at least one of the following configurations.

[0009] The plurality of magnetic bodies constituting the spokes may be biased in the radial direction. The annular yoke may include a plurality of openings arranged in a circumferential direction, wherein each of the plurality of openings may include an inner surface on the one end surface side of the annular yoke and an inner surface on the other end surface side of the annular yoke. The plurality of spokes may extend in the radial direction and pass through the plurality of openings, and the plurality of magnetic bodies constituting the spokes may be biased from the inner surface on the one end surface side of the annular yoke to the inner surface on the other end surface side of the annular yoke.When the motor includes the plurality of openings, the number of the plurality of magnetic bodies constituting the spokes may be less than the number of a plurality of magnetic bodies constituting the plurality of openings of the plurality of magnetic bodies constituting the annular yoke. The plurality of spokes may include a plurality of hole portions extending in the axial direction, and members inserted into the plurality of hole portions may bias the plurality of magnetic bodies constituting the spokes. When the motor includes the plurality of hole portions, each of the plurality of hole portions may be adjacent to the annular yoke in the radial direction. When each of the plurality of hole portions is adjacent to the annular yoke in the radial direction, each of the members may contact a side surface of the annular yoke.When each of the elements contacts the side surface of the annular yoke, each of the elements may include a side surface inclined relative to a side surface of the annular yoke. The thickness in the axial direction of each of the plurality of magnetic bodies constituting the spokes may be equal to the thickness in the axial direction of each of the plurality of magnetic bodies constituting the annular yoke. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view of an engine according to a first embodiment, which is an example of the present invention. Fig. 2 is a cross-sectional view of only a bearing device in the engine according to the first embodiment, which is an example of the present invention. Fig. 3 is a cross-sectional view of only a bearing device in the engine according to a second embodiment, which is an example of the present invention. Fig. 4 is a cross-sectional view of only a bearing device in the engine according to a third embodiment, which is an example of the present invention. Fig. 5 is a cross-sectional view of only a bearing device in the engine according to a fourth embodiment, which is an example of the present invention. Fig. 6 is a cross-sectional view of only a bearing device in the engine according to a fifth embodiment, which is an example of the present invention. Fig. 7 is a perspective view illustrating a motor according to a sixth embodiment, which is another example of the present invention. Fig. 8 is a plan view of the Fig. 7 illustrated motor when viewed from one side in an axial direction. Fig. 9 is a cross-sectional view of the Fig. 7 illustrated motor in a radial direction. Fig. 10 is a cross-sectional view of the Fig. 7 illustrated motor in an axial direction. Fig. 11 is a plan view showing a state of the Fig. 8, with the bearing assembly removed. Fig. 12 is a cross-sectional view taken along the Fig. 11 illustrated line AA. Fig. 12A is a view schematically illustrating the state of a side surface of each magnetic body. Fig. 13 is a perspective view illustrating a state in which one of the Fig. 11 illustrated plurality of stator elements was removed from a yoke. Fig. 14 is a plan view illustrating a state in which one of the Fig. 11 illustrated plurality of stator elements is guided through an opening in the yoke. Fig. 15 is a perspective view showing a Fig. 7 illustrated printing element. Fig. 16 is a side view showing the Fig. 15 illustrated printing element. Fig. 17 is a perspective view showing a state at the beginning of the insertion of the Fig. 15 illustrated pressure element into a hole part of the yoke. Fig. 18 is a perspective view illustrating a motor according to a seventh embodiment, which is another example of the present invention. Fig. 19 is a perspective view showing the Fig. 18 illustrated printing element. Fig. 20 is a view from below showing the Fig. 18 illustrated printing element. DESCRIPTION OF EMBODIMENTS

[0010] In the descriptions of the first embodiment to the fifth embodiment of the present invention, for the sake of illustration, an arrow a in the direction of an axis X in each drawing (direction from a second bearing 113b to a first bearing 113a) is defined as a lower side or one side. A direction of arrow b (direction from the first bearing 113a to the second bearing 113b) along the axis X is defined as an upper side or the other side. The direction of arrows a, b here is referred to as an up-down direction or an axial direction. However, the up-down direction does not necessarily coincide with a vertical direction. The direction of arrows c, d is referred to as a radial direction. The direction of arrow c extending away from the axis X is referred to as an outer side, and the direction of arrow d closer to the axis X is referred to as an inner side. First embodiment

[0011] A first embodiment which is an example of the present invention will be described below with reference to the drawings. Fig. 1 is a cross-sectional view cut along a plane of a motor 100 according to the present embodiment, the plane including the X-axis. Fig. 2 is a view that only shows one of Fig. 1 extracted storage device 110 is illustrated.

[0012] As in Fig. As illustrated in FIG. 1, the motor 100 includes the bearing device 110, a coil 120, a magnetic body 130, a housing 140, and a cover 150. In the present embodiment, the magnetic body 130 is composed of a plurality of magnetic bodies (electromagnetic steel plates) stacked in the axial direction. The housing 140 is a tubular member including a bottom portion and open on the other side in the axial direction (arrow b direction). The housing 140 includes a tubular portion (cylindrical portion) 141, a bottom portion 142, and a protruding portion 143 having an annular shape. The cylindrical portion 141 is a portion having a cylindrical shape with the X axis as a central axis.The bottom part 142 is a flat plate part having an annular shape and extending from one end part of the cylindrical part 141 on one side in the axial direction (arrow a direction) to the inner side in the radial direction (arrow d direction). The protruding part 143 is a part having a cylindrical shape that extends from one end part of the bottom part 142 on the inner side in the radial direction (arrow d direction) to the other side in the axial direction (arrow b direction). In the axial direction, a length of the cylindrical part 141 is greater than a length of the protruding part 143.

[0013] The lid 150 is a lid-like member that covers the opening on the other side in the axial direction (direction of arrow b) of the cylindrical part 141 of the housing 140 and includes a flat plate part 151, an outer peripheral part (engaging part) 152, and an inner peripheral part (projecting part) 153. The flat plate part 151 is a part having an annular shape with the X axis as a central axis. An outer periphery and an inner periphery of the flat plate part 151 have the same or substantially the same size (outer diameter and inner diameter) as the housing 140 in the radial direction.The engagement part 152 is a part having an annular shape that protrudes from an end part of the flat plate part 151 on the outer side in the radial direction (arrow c direction) on a slightly inner side in the radial direction (arrow d direction) to one side. The protruding part 153 is a part having a cylindrical shape that protrudes from an end part of the flat plate part 151 on the inner side in the radial direction (arrow a direction) to one side in the axial direction (arrow d direction). In the axial direction, a length of the engagement part 152 is substantially equal to a length of the protruding part 153.

[0014] The engaging part 152 of the cover 150 is engaged with an end part (outer peripheral end part) of the cylindrical part 141 of the housing 140 on the other side in the axial direction (arrow b direction). A size (outer diameter) of the engaging part 152 of the cover 150 in the radial direction is equal to or substantially equal to a size (inner diameter) of the cylindrical part 141 of the housing 140, and the engaging part 152 of the cover 150 is inserted into an inner side in the radial direction (arrow d direction) of the end part of the cylindrical part 141 of the housing 140 on the other side in the axial direction (arrow b direction). The engaging part 152 of the cover 150 is fixed to the cylindrical part 141 of the housing 140 by adhesive bonding or press-fitting.

[0015] An inner diameter of the protruding part 143 of the housing 140 is equal to an inner diameter of the protruding part 153 of the cover 150. In the radial direction, an outer surface of a cover 114 (described below), which has a cylindrical shape, of the bearing device 110 is fixed to an inner surface of the protruding part 143 of the housing 140 and an inner surface of the protruding part 153 of the cover 150 with an adhesive or the like. The coil 120 and the magnetic body 130 are housed in a cylindrical space defined by the housing 140, the cover 150, and the cover 114 of the bearing device 110. The cylindrical space has the axis X as a central axis. Accordingly, the cover 114 of the bearing device 110 is arranged inside the coil 120 in the radial direction (in the direction of arrow d).

[0016] The magnetic body 130 is formed of a stacked body comprising a plurality of electromagnetic steel plates made of a soft magnetic material and stacked in the axial direction. The magnetic body 130 is bonded to a surface of the cylindrical part 141 of the housing 140 on the inner side in the radial direction (arrow d direction) and extends toward the inner side in the radial direction (arrow d direction) to the vicinity of the cover 114 of the bearing device 110. In the motor 100 according to the present embodiment, six magnetic bodies 130 are radially arranged at equal angular intervals in a circumferential direction. However, the number of magnetic bodies 130 is not limited to six. The coil 120 is wound around each magnetic body 130 through an insulator (not illustrated).

[0017] As in Fig. 2, the bearing device 110 includes a shaft S, a magnet 112, the first bearing 113a, the second bearing 113b, the cover 114, a holder 115, and an elastic member 116. In the radial direction, the shaft S, the magnet 112, the first bearing 113a, and the second bearing 113b are arranged inside the cover 114. That is, in the radial direction, the cover 114 has a sleeve shape that covers the shaft S, the magnet 112, the first bearing 113a, and the second bearing 113b. Further, the cover 114 includes one end part 114a on the first bearing 113a side and another end part 114b on the second bearing 113b side. The cover 114 is formed of, for example, ceramic. However, the cover 114 may also be formed of another material, such as a non-magnetic metal or resin.

[0018] The shaft S is a member having a columnar or substantially columnar shape extending in the axial direction. The shaft S includes one end portion S1 on the first bearing 113a side and another end portion S2 on the second bearing 113b side. In the axial direction, the first bearing 113a is disposed on the one end portion S1 side of the shaft S. In the axial direction, the second bearing 113b is disposed on the other end portion S2 side of the shaft S.

[0019] The first bearing 113a is a ball bearing including an inner ring 113ai, an outer ring 113ao, and rolling elements. The first bearing 113a is not limited to a ball bearing having this shape, but may be any other bearing, such as a plain bearing and a ball bearing including balls fitted into recesses on an outer peripheral surface of the shaft and an outer ring. The inner ring 113ai of the first bearing 113a is press-fitted or bonded to a surface of the shaft S on an outer side in the radial direction (direction of arrow c). Thus, the inner ring 113ai of the first bearing 113a is fixed to the shaft S.

[0020] The second bearing 113b has the same dimensions and configuration as the first bearing 113a. The second bearing 113b is a ball bearing including an inner ring 113bi, an outer ring 113bo, and rolling elements. The second bearing 113b is not limited to a ball bearing having this shape, but may be any other bearing, such as a plain bearing or a ball bearing including balls fitted into recesses on the outer peripheral surface of the shaft and an outer ring. The inner ring 113bi of the second bearing 113b is press-fitted or bonded to the surface of the shaft S on the outer side in the radial direction (direction of arrow c). Thus, the inner ring 113bi of the second bearing 113b is fixed to the shaft S.

[0021] The other end portion 114b of the cover 114, which has a cylindrical shape, is fixed to an outer side (in the direction of arrow c) of the outer ring 113bo of the second bearing 113b in the radial direction by a spacer 119 having an annular shape. In the axial direction, a length of the spacer 119 is equal to or substantially equal to a length of the second bearing 113b. In the radial direction, an inner diameter of the spacer 119 is equal to or substantially equal to an outer diameter of the outer ring 113bo of the second bearing 113b, and an outer diameter of the spacer 119 is equal to or substantially equal to an inner diameter of the cover 114.A surface of the outer ring 113bo of the second bearing 113b on the outer side in the radial direction (arrow c direction) and a surface of the spacer 119 on the inner side in the radial direction (arrow d direction) are fixed to each other, and the surface of the spacer 119 on the outer side in the radial direction (arrow c direction) and a surface of the cover 114 on the inner side in the radial direction (arrow d direction) are fixed to each other by press-fitting or bonding. The second bearing 113b supports the shaft S relatively rotatably with respect to the cover 114.

[0022] One end part (other end part 115h) of the holder 115 on the other side in the axial direction (arrow b direction) is fixed to an outer side (arrow c direction) of the outer ring 113ao of the first bearing 113a in the radial direction. A surface of the outer ring 113ao of the first bearing 113a on the outer side in the radial direction (arrow c direction) and a surface of an inner peripheral part 115a of the holder 115 described below on the inner side in the radial direction (arrow d direction) are fixed to each other by press-fitting or bonding. The first bearing 113a supports the shaft S relatively rotatably with respect to the holder 115.

[0023] The holder 115 has a three-dimensional shape obtained by rotating a cross section having a substantially J-like shape around the X-axis. The holder 115 is formed of a metal such as aluminum, copper, or iron. However, the holder 115 may also be formed of other materials such as synthetic resin. The holder 115 may be formed of a material that is softer than the material of the cover 114. The holder 115 includes the inner peripheral part 115a, a connecting part 115b, and an outer peripheral part 115c. This connecting part 115b forms one end part 115g of the holder 115, and the holder 115 includes one end part 115g and the other end part 115h.

[0024] The inner peripheral part 115a is a part having a cylindrical shape extending in the axial direction. In the radial direction, a thickness of the inner peripheral part 115a is equal to or substantially equal to a thickness of the spacer 119. In the radial direction, an inner diameter and an outer diameter of the inner peripheral part 115a are equal to or substantially equal to the inner diameter and outer diameter of the spacer 119, respectively. In the axial direction, the inner peripheral part 115a has a length greater than a length of the first bearing 113a.

[0025] The connecting part 115b is a part having an annular shape extending from an end part of the inner peripheral part 115a on one side in the axial direction (arrow a direction) to the outer side in the radial direction (arrow c direction). The outer peripheral part 115c is a part having a cylindrical shape extending from an end part of the connecting part 115b on the outer side in the radial direction (arrow d direction) toward the other side in the axial direction (arrow b direction). In the axial direction, a length of the outer peripheral part 115c is smaller than the length of the inner peripheral part 115a.

[0026] In the holder 115, an annular space surrounded by the inner peripheral part 115a, the connecting part 115b, and the outer peripheral part 115c is referred to as the accommodation part 115d. In the axial direction, the accommodation part 115d has a depth equal to the length of the outer peripheral part 115c. In the radial direction, the width of the accommodation part 115d, that is, a distance between the inner peripheral part 115a and the outer peripheral part 115c, is equal to or slightly larger than the thickness of the cover 114.

[0027] The elastic member 116 is housed in the housing portion 115d of the holder 115. That is, the holder 115 holds the elastic member 116. One housing portion 114a of the cover 114 is inserted into the housing portion 115d from the other side of the one housing portion 115d in the axial direction (direction of arrow b). A contact portion between the cover 114 and the holder 115 is slidable in the axial direction. The elastic member 116 is arranged between the cover 114 and the holder 115 in the axial direction (longitudinal direction of the shaft S), that is, between one end part 114a of the cover 114 and a surface of the connecting part 115b of the holder 115 on the other side in the axial direction (direction of arrow b) (that is, a lower surface forming the accommodation part 115d).The elastic member 116 contacts both the one end part 114a of the cover 114 and the surface of the connecting part 115b of the holder 115 on the other side in the axial direction (direction of arrow b) and is held by both.

[0028] In the present embodiment, the elastic member 116 is a coil having a substantially cylindrical spiral shape with the X axis as the central axis. However, the elastic member 116 may be formed of a rubber-elastic material and have various shapes. Examples of the material having rubber elasticity include thermosetting elastomers such as natural rubber and synthetic rubber, and thermoplastic elastomers such as styrene-based elastomers, olefin-based elastomers, vinyl chloride-based elastomers, acrylic-based elastomers, polyamide-based elastomers, polyester-based elastomers, and polyurethane-based elastomers. A plurality of the elastic members 116 may be arranged circumferentially adjacent to one another on the housing part 115d.

[0029] The elastic member 116 urges the cover 114 and the holder 115 in the axial direction. More specifically, the elastic member 116 urges the cover 114 and the holder 115 in the axial direction in directions away from each other. That is, the elastic member 116 urges the cover 114 toward the upper side in the axial direction (direction of arrow b). The elastic member 116 urges the holder 115 toward the lower side in the axial direction (direction of arrow b).

[0030] As described above, the other end portion 114b of the cover 114, which has a cylindrical shape, is fixed to the outer side (in the direction of arrow c) of the outer ring 113bo of the second bearing 113b in the radial direction by the spacer 119 having an annular shape, and the retainer 115 is fixed to the outer side (in the direction of arrow c) of the outer ring 113ao of the first bearing 113a in the radial direction. Thus, the elastic member 116 applies a preload to the outer ring 113ao of the first bearing 113a and the outer ring 113bo of the second bearing 113b to increase the distance from each other in the axial direction.

[0031] In the present embodiment, the magnet 112 is a cylindrical permanent magnet having four magnetic poles. In the cylindrical permanent magnet, different magnetic poles (S poles and N poles) are alternately magnetized in the circumferential direction. However, the number of magnetic poles of the magnet 112 is not limited to four, but may be any other number. In the radial direction, the inner diameter of the magnet 112 is equal to or slightly larger than the outer diameter of the shaft S. The magnet 112 is fixed to the surface of the shaft S on the outer side in the radial direction (direction of arrow c) by bonding or press-fitting. In the axial direction, the magnet 112 is arranged between the first bearing 113a and the second bearing 113b so as to be separated from the first bearing 113a and the second bearing 113b by predetermined distances.A size (outer diameter) Q1 of the magnet 112 in the radial direction is larger than a size (outer diameter) P of the first bearing 113a and the second bearing 113b in the radial direction.

[0032] A protective member 118 having a cylindrical shape is provided to cover a surface (outer surface) of the magnet 112 on the outer side in the radial direction (arrow c direction). The protective member 118 is provided, for example, to prevent breakage or scattering of the magnet 112. However, the motor 100 does not need to include the protective member 118. In the radial direction, a surface of the protective member 118 on the outer side (arrow c direction) and the surface of the cover 114 on the inner side (arrow d direction) are spaced apart from each other and face each other.

[0033] A member (first pressure member) 117a is disposed between the magnet 112 and the first bearing 113a in the axial direction. A member (second pressure member) 117b is disposed between the magnet 112 and the second bearing 113b in the axial direction. The first pressure member 117a and the second pressure member 117b have the same shape and dimensions and are arranged symmetrically with respect to a plane orthogonal to the X-axis while sandwiching the magnet 112.

[0034] The first pressing member 117a and the second pressing member 117b respectively include annular parts 117a1 and 117b1, contact parts 117a2 and 117b2, and protruding parts 117a3 and 117b3. In the radial direction, an inner diameter of the annular parts 117a1 and 117b1 is equal to or slightly larger than the outer diameter of the shaft S. The annular parts 117a1 and 117b1 are fixed in the radial direction (direction of arrow c) to the surface of the shaft S on the outer side by bonding or press-fitting. In the radial direction, an outer diameter of the annular parts 117a1 and 117b1 is slightly larger than an outer diameter of the magnet 112 and is equal to or substantially equal to an outer diameter of the protective member 118.

[0035] The contact parts 117a2 and 117b2 are parts having an annular shape that protrude in the axial direction from surfaces of the annular parts 117a1 and 117b1 near the magnet 112 and contact the magnet 112. The contact parts 117a2 and 117b2 protrude from regions of the surfaces of the annular parts 117a1 and 117b1 on sides near the magnet 112 near the outer side in the radial direction (direction of arrow c).

[0036] The protruding parts 117a3 and 117b3 are parts having an annular shape that protrude in the axial direction from surfaces of the annular parts 117a1 and 117b1 away from the magnet 112 and contact the inner ring 113ai of the first bearing 113a and the inner ring 113bi of the second bearing 113b, respectively. The protruding parts 117a3 and 117b3 protrude from the respective regions of the annular parts 117a1 and 117b1 on the inner side in the radial direction (arrow d direction).

[0037] The first pressure element 117a and the second pressure element 117b press against the inner ring 113ai of the first bearing 113a and the inner ring 113bi of the second bearing 113b, respectively. The first pressure element 117a and the second pressure element 117b are formed from a metal such as copper. The first pressure element 117a and the second pressure element 117b may be formed from other materials, but are preferably formed from heavy metals to serve as balancing elements for adjusting rotational balance of the shaft S.

[0038] The motor 100 is an internal rotor type brushless DC motor. When the motor 100 is operated, the shaft S, the magnet 112, the inner ring 113ai of the first bearing 113a, the inner ring 113bi of the second bearing 113b, the first thrust member 117a, the second thrust member 117b, and the protection member 118 rotate integrally.

[0039] The motor 100 according to the present embodiment can be manufactured by a method of assembling the configuration on the stator side, that is, the coil 120, the magnetic body 130, the housing 140, and the cover 150, and then inserting the separately assembled bearing device 110. Thus, both coaxiality between the rotor side and the stator side and coaxiality between the first bearing 113a and the second bearing 113b can be improved.

[0040] In the motor 100 according to the present embodiment, preloads are applied to the outer ring 113ao of the first bearing 113a and the outer ring 113bo of the second bearing 113b to increase the distance from each other in the axial direction. Thus, the motor 100 has a high resonance frequency and is suitable for high-speed applications. The preloads are applied by the elastic member 116 arranged between the cover 114 and the holder 115. Accordingly, the motor 100 according to the present embodiment does not need to sandwich a spring between the outer ring 113ao of the first bearing 113a and the outer ring 113bo of the second bearing 113b, which frees up space in an interior of the cover 114 and makes it possible to increase the outer diameter of the magnet 112 and construct a motor with high torque. Second embodiment

[0041] Next, a second embodiment which is an example of the present invention will be described with reference to the drawings. Fig. 3 is a cross-sectional view of only one bearing device 210 of a motor according to the present embodiment. The motor according to the present embodiment has a configuration similar to the configuration of the motor 100 according to the first embodiment, except that the bearing device 210 is provided instead of the bearing device 110. The bearing device 210 has a configuration similar to the configuration of the bearing device 110 of the motor 100 according to the first embodiment, except that the bearing device 210 includes a yoke 211 and a magnet 212 instead of the magnet 112. Elements and components having the same functions and configurations as the elements and components of the first embodiment are denoted by the same reference numerals of the first embodiment, and detailed descriptions of the elements and components are omitted below.

[0042] In the present embodiment, the magnet 212 is a permanent magnet having a cylindrical shape and four magnetic poles. In the permanent magnet, different magnetic poles (S poles and N poles) are alternately magnetized in a circumferential direction. However, the number of magnetic poles of the magnet 212 is not limited to four, but may be any other number. In the radial direction, an inner diameter of the magnet 212 is larger than the outer diameter of the shaft S. For example, an outer diameter of the magnet 212 is equal to the outer diameter of the magnet 112 of the motor 100 according to the first embodiment. The magnet 212 is fixed to the shaft S by the yoke 211 having a cylindrical shape.

[0043] In the axial direction, a length of the yoke 211 is equal to or substantially equal to a length of the magnet 212. In the radial direction, an inner diameter of the yoke 211 is equal to the outer diameter of the shaft S or slightly larger than the outer diameter of the shaft S. In the radial direction, an outer diameter of the yoke 211 is equal to the inner diameter of the magnet 212 or slightly smaller than the inner diameter of the magnet 212. The surface of the shaft S on the outer side in the radial direction (direction of arrow c) and a surface of the yoke 211 on the inner side in the radial direction (direction of arrow d) are fixed to each other, and a surface of the yoke 211 on the outer side in the radial direction (direction of arrow c) and a surface of the magnet 212 on the inner side in the radial direction (direction of arrow d) are fixed to each other by press-fitting or bonding.

[0044] In the axial direction, the yoke 211 and the magnet 212 are arranged between the first bearing 113a and the second bearing 113b, separated from the first bearing 113a and the second bearing 113b. A size (outer diameter) Q2 of the magnet 212 in the radial direction is larger than the size (outer diameter) P of the first bearing 113a and the second bearing 113b in the radial direction.

[0045] The motor according to the present embodiment has high coaxiality and high torque based on a principle similar to that of the motor 100 according to the first embodiment described above. Fixing the magnet 212 to the shaft S via the yoke 211 can prevent the magnet 212 from breaking and easily magnetize the magnet 212. Third embodiment

[0046] Next, a third embodiment which is an example of the present invention will be described with reference to the drawings. Fig. 4 is a cross-sectional view of only one bearing device 310 in the motor according to the present embodiment. The motor according to the present embodiment has a configuration similar to the configuration of the motor 100 according to the first embodiment, except that the bearing device 310 is provided instead of the bearing device 110. The bearing device 310 has a configuration similar to the configuration of the bearing device 110 of the motor 100 according to the first embodiment, except that the bearing device 310 does not include the spacer 119 and includes a cover 314 instead of the cover 114. Elements and components having the same functions and configurations as the elements and components of the first embodiment are denoted by the same reference numerals of the first embodiment, and detailed descriptions of the elements and components are omitted below.

[0047] In the present embodiment, the cover 314 of the bearing device 310 has a shape that integrates the cover 114 and the spacer 119 of the motor 100 according to the present embodiment. The cover 314 includes one end part 314a on the first bearing 113a side and another end part 314b on the second bearing 113b side. The cover 314 includes a thick part 314c at the other end part 314b. The thick part 314c has an equivalent outer diameter and a small inner diameter compared to the other parts of the cover 314.

[0048] In the radial direction, the thick part 314c of the cover 314 is directly fixed to the outer side (in the direction of arrow c) of the outer ring 113bo of the second bearing 113b. In the axial direction, a length of the thick part 314c is equal to or substantially equal to the length of the second bearing 113b. The surface of the outer ring 113bo of the second bearing 113b on the outer side in the radial direction (direction of arrow c) and a surface of the thick part 314c of the cover 314 on the inner side in the radial direction (direction of arrow d) are fixed to each other by press-fitting or bonding.

[0049] The motor according to the present embodiment has high coaxiality and high torque based on a principle similar to that of the motor 100 according to the first embodiment described above. The motor according to the present embodiment has a small number of components compared to the motor 100 according to the first embodiment and can be easily assembled. Fourth embodiment

[0050] Next, a fourth embodiment which is an example of the present invention will be described with reference to Fig. 5 described. Fig. 5 is a cross-sectional view of only one bearing device 410 of the motor according to the present embodiment. The motor according to the present embodiment has a configuration similar to the configuration of the motor 100 according to the first embodiment, except that the bearing device 410 is provided instead of the bearing device 110. The bearing device 410 has the same configuration as the bearing device 110 of the motor 100 according to the first embodiment, except that it includes a cover 414 instead of the cover 114, a holder 415 instead of the holder 115, and an elastic member 416 instead of the elastic member 116.Elements and components having the same functions and configurations as the elements and components of the first embodiment are denoted by the same reference numerals of the first embodiment, and detailed descriptions of the elements and components are omitted below.

[0051] The cover 414 includes one end portion 414a on the first bearing 113a side and another end portion 414b on the second bearing 113b side. In the axial direction, one end portion 414a of the cover 414 further extends to the one side as an end surface of the first bearing 113a on the one side in the axial direction. The holder 415 has a three-dimensional shape obtained by rotating a cross section having a substantially J-like shape around the axis X. The holder 415 includes an inner peripheral portion 415a, a connecting portion 415b, and an outer peripheral portion 415c. The connecting portion 415b forms one end portion 415g of the holder 415, and the holder 415 includes the one end portion 415g and another end portion 415h.A size of the connecting part 415b of the holder 415 in the radial direction is larger than a size of the connecting part 115b of the holder 115 in the radial direction in the first embodiment. The cover 414, the holder 415, and the elastic member 416 have configurations similar to the configurations of the cover 114, the holder 115, and the elastic member 116 in the first embodiment, respectively, unless otherwise stated.

[0052] In the present embodiment, the elastic member 416 is arranged on the one end part S1 side of the shaft S in the axial direction with respect to the first bearing 113a. In the axial direction, the elastic member 416 is positioned between the first bearing 113a and the one end part S1 side of the shaft S. Furthermore, the elastic member 416 is positioned at a predetermined distance D from the first bearing 113a in the axial direction toward the one end part S1 side of the shaft S. The cover 414 partially or entirely supports an outer peripheral surface of the first bearing 113a via the holder 415. The elastic member 416 is located between the one end part 414a of the cover 414 and the holder 415 in the axial direction. A size (outer diameter) of the elastic member 416 in the radial direction is larger than the size (outer diameter) of the cover 414 in the radial direction.Specifically, in the radial direction, an outer peripheral part of the elastic member 416 is larger than an outer surface of the cover 414.

[0053] The holder 415 includes an opening portion 415e. A space T is formed inside the holder 415 in the radial direction. The first bearing 113a faces this space T in the axial direction. Then, in the radial direction, this space T and the elastic member 416 face each other through the inner peripheral portion 415a of the holder 415. In the axial direction, the elastic member 416 is disposed on the one end portion S1 side of the shaft S further than the end surface of the first bearing on one side in the axial direction.

[0054] The motor according to the present embodiment has high coaxiality and high torque based on a principle similar to that of the motor 100 according to the first embodiment described above. The elastic member 416 is arranged on the one end portion S1 side of the shaft S with respect to the first bearing 113a, and thus the cover 414 can absorb a load applied in the radial direction from the shaft S to the first bearing 113a. Furthermore, the cover 414 can suppress displacement of the first bearing 113a in the radial direction. The holder can hold the elastic member 416 regardless of the size of the elastic member 416, thereby making it possible to select a shape and material of the elastic member 416 and adjust an elastic force (or spring constant) applied to the cover 414. Fifth embodiment

[0055] Next, a fifth embodiment which is an example of the present invention will be described with reference to the drawings. Fig. 6 is a cross-sectional view of only one bearing device 510 of the motor according to the present embodiment. The motor according to the present embodiment has a configuration similar to the configuration of the motor 100 according to the first embodiment, except that the bearing device 510 is provided instead of the bearing device 110. The bearing device 510 has the same configuration as the bearing device 110 of the motor 100 according to the first embodiment, except that it includes a member 517a and a member 517b instead of the first pressing member 117a and the second pressing member 117b (however, the bearing device 510 does not need to include the member 517a and the member 517b), does not include a protective member 118 (however, the bearing device 510 may include the protective member 118), and includes balance members (first ring Ra and second ring Rb).Elements and components having the same functions and configurations as the elements and components of the first embodiment are denoted by the same reference numerals of the first embodiment, and detailed descriptions of the elements and components are omitted below.

[0056] The element 517a, which has an annular shape, is arranged between the magnet 112 and the first bearing 113a in the axial direction. The element 517b, which has an annular shape, is arranged between the magnet 112 and the second bearing 113b in the axial direction. The elements 517a and 517b have the same shape and dimensions and are arranged symmetrically with respect to the plane orthogonal to the X-axis, sandwiching the magnet 112.

[0057] In the radial direction, the inner diameters of the elements 517a and 517b are equal to the outer diameter of the shaft S or slightly larger than the outer diameter of the shaft S. The elements 517a and 517b are fixed in the radial direction (direction of arrow c) to the surface of the shaft S on the outer side by adhesive bonding or press-fitting. In the radial direction, outer diameters of the elements 517a and 517b are smaller than an outer diameter of the magnet 112. In the radial direction, the outer diameters of the elements 517a and 517b are slightly larger than the inner diameters of the inner ring 113ai of the first bearing 113a and the inner ring 113bi of the second bearing 113b and slightly smaller than the inner diameters of the outer ring 113ao of the first bearing 113a and the outer ring 113bo of the second bearing 113b.

[0058] In the axial direction, a surface of the element 517a on one side (in the direction of arrow a) contacts a surface of the inner ring 113ai of the first bearing 113a on the other side (in the direction of arrow b). In the axial direction, a surface of the element 517a on the other side (in the direction of arrow b) contacts a surface of the magnet 112 on one side (in the direction of arrow a). In the axial direction, a surface of the element 517b on the other side (in the direction of arrow b) contacts a surface of the inner ring 113bi of the second bearing 113b on one side (in the direction of arrow a). In the axial direction, a surface of the element 517b on one side (in the direction of arrow a) contacts a surface of the magnet 112 on the other side (in the direction of arrow b).

[0059] Element 517a and element 517b preload the inner ring 113ai of the first bearing 113a and the inner ring 113bi of the second bearing 113b, respectively. Element 517a and element 517b are formed from a metal such as copper. Element 517a and element 517b may be formed from other materials such as resin or ceramic.

[0060] In the axial direction, the first ring Ra is arranged on one side (in the direction of arrow a) of the first bearing 113a so as to be spaced apart from the first bearing 113a. The second ring Rb is arranged on the other side (in the direction of arrow b) of the second bearing 113b in the axial direction so as to be spaced apart from the second bearing 113b. In the axial direction, the first ring Ra on one side (in the direction of arrow a) is arranged farther away than an end part of the cover 114 on one side (in the direction of arrow a). In the axial direction, the second ring Rb on the other side (in the direction of arrow b) is arranged farther away than the end part of the cover 114 on the other side (in the direction of arrow b). In other words, the first ring Ra and the second ring Rb are arranged on the outer side of the cover 114 in the axial direction.The motor according to the present embodiment may include only one of the two rings Ra or Rb.

[0061] In the radial direction, the sizes of the inner peripheral surfaces (inner diameters) of the first ring Ra and the second ring Rb are equal to the outer diameter of the shaft S or slightly larger than the size of an outer peripheral surface (outer diameter) of the shaft S. The first ring Ra and the second ring Rb are fixed on the outer side in the radial direction (direction of arrow c) by bonding or press-fitting to the surface of the shaft S. In the radial direction, the sizes of the outer peripheral surfaces (outer diameters) of the first ring Ra and the second ring Rb are smaller than an outer diameter of the cover 114. However, in the radial direction, the outer diameters of the first ring Ra and the second ring Rb may be larger than the outer diameter of the cover 114.

[0062] The first ring Ra and the second ring Rb are formed from a metal such as copper or non-magnetic bodies. The first ring Ra and the second ring Rb can be formed from other materials, but since they can serve as balancing elements configured to adjust the rotational balance of the shaft S, they are preferably formed from materials with high specific gravities.

[0063] The motor according to the present embodiment has high coaxiality and high torque based on a principle similar to that of the motor 100 according to the first embodiment described above. Omitting at least one of the first ring Ra and the second ring Rb enables adjustment of the rotation balance even after assembling the motor according to the present embodiment. The motor according to the present embodiment, by including the first ring Ra and the second ring Rb, makes it possible to ensure a sufficient excess volume for scraping at the time of adjusting the rotation balance and to improve the rotation balance. The rotation balance can be adjusted using, for example, a self-propelled balancing machine.

[0064] As described above, the motor according to the present invention has been described with reference to preferred embodiments, but the motor according to the present invention is not limited to the configurations of the above-described embodiments. For example, although the housing 140 has a cylindrical shape in the above-described embodiments, the housing in the motor according to the present invention may have any shape. In the above-described embodiments, the bearing devices 110, 210, 310, and 410 include the first pressing member 117a and the second pressing member 117b. However, in the motor according to the present invention, the bearing device may include only one of the pressing members or may not include any pressing member at all. The first pressing member 117a and the second pressing member 117b do not need to have the same shape and dimensions.

[0065] In the above-described embodiments, the outer diameters Q1 and Q2 of the magnets 112 and 212 are larger than the outer diameter P of the first bearing 113a and the second bearing 113b. However, in the motor according to the present invention, the outer diameters of the magnets may be equal to the outer diameters of the bearings or smaller than the outer diameters of the bearings. In the above-described embodiments, the second bearing 113b has the same dimensions and configurations as the first bearing 113a, but in the motor according to the present invention, the first bearing and the second bearing may have different dimensions and configurations from each other.

[0066] Embodiments for implementing a motor according to the present invention (sixth and seventh embodiments) will be described below together with the accompanying drawings. The embodiments described below are intended to facilitate understanding of the present invention and are not to be construed as limiting the present invention. The present invention can be modified and improved from the following embodiments without departing from the spirit of the present invention. In the accompanying drawings described above, the dimensions of individual elements may be exaggerated or reduced, or hatching may be omitted, for ease of understanding.The motors according to the sixth and seventh embodiments may include a configuration similar to the configurations of the motors according to the first to fifth embodiments, but the names of the elements in the motors according to the first to fifth embodiments may be different from the names of the corresponding elements of the motors according to the sixth and seventh embodiments for convenience of description.

[0067] A known motor includes a stator including a yoke portion on an outer peripheral side and a plurality of tooth portions extending inward in the radial direction from this yoke portion, with a coil wound around each of the tooth portions (see, for example, JP 2012-105397 A). The motor described in this document and other motors may require a large space for a coil. The sixth and seventh embodiments are examples of providing a motor wound with a large space for a coil. Sixth embodiment

[0068] Fig. 7 is a perspective view illustrating a motor 1001 according to the present embodiment. Fig. 8 is a plan view of the motor 1001 when viewed from one side in the axial direction. Fig. 9 is a cross-sectional view of the motor 1001 in the radial direction. Fig. 10 is a cross-sectional view of the motor 1001 in the axial direction.

[0069] As in Fig. 7 to 10, the motor 1001 as a whole has a substantially cylindrical shape and includes, as a main configuration, a bearing device 1010 having a cylindrical shape and arranged at a center of the motor 1001, a yoke 1030 having a cylindrical shape (ring shape) and surrounding the bearing device 1010, a stator 1040 arranged radially from the bearing device 1010 toward the yoke 1030, a plurality of coils 1050 wound around the stator 1040, and a plurality of pressing elements (elements) 1060 inserted into hole parts formed in the stator 1040. In Fig. 7, only one printing element 1060 is illustrated for the sake of simplicity.

[0070] The bearing device 1010 includes a shaft 1011 arranged at the center of the motor 1001 in the radial direction. In the sixth and seventh embodiments, a side close to the shaft 1011 in the radial direction may be referred to as an "inner side" or simply "inner," and a side far from the shaft 1011 in the radial direction may be referred to as an "outer side" or simply "outer." The shaft 1011 is a rotation axis of the motor 1001, and a longitudinal direction of the shaft 1011 is an axial direction of the motor 1001.

[0071] As in Fig. 10, the bearing device 1010 further includes a pair of bearings 1013a and 1013b, a pair of intermediate members 1017a and 1017b, a magnet 1014 having a cylindrical shape, a protective member 1018, a cover 1012 having a cylindrical shape, a holder 1015, and the like.

[0072] The cover 1012 accommodates the shaft 1011, the magnet 1014, the pair of bearings 1013a and 1013b, the pair of intermediate members 1017a and 1017b, the magnet 1014, the protective member 1018, and the like. That is, the shaft 1011, the magnet 1014, the pair of bearings 1013a and 1013b, the pair of intermediate members 1017a and 1017b, the magnet 1014, the protective member 1018, and the like are disposed inside an inner peripheral surface of the cover 1012. On the other hand, the stator 1040, the plurality of coils 1050, the yoke 1030, and the like are disposed outside an outer peripheral surface 1012a of the cover 1012. For example, the cover 1012 may be fixed to a motor housing (not illustrated) together with the yoke 1030. In the present embodiment, the cover 1012 is formed of ceramic. However, the cover 1012 may also be formed of another material, such as a non-magnetic metal or resin.

[0073] In the present embodiment, the pair of bearings 1013a and 1013b are each configured as ball bearings. However, the pair of bearings 1013a and 1013b may be any of various other bearings, such as a plain bearing and a ball bearing including balls fitted into recesses in an outer peripheral surface of the shaft and an outer ring. In the axial direction of the pair of bearings 1013a and 1013b, the bearing 1013a is arranged near an end portion of the shaft 1011 on one side, and the bearing 1013b is arranged near an end portion of the shaft 1011 on the other side.

[0074] In the sixth and seventh embodiments, one side in the axial direction (side of the bearing 1013a) may be referred to as "upper side", "top", or simply "upper", and the other side in the axial direction (side of the bearing 1013b) may be referred to as "lower side", "bottom", or simply "lower".

[0075] The bearing 1013a includes an inner ring 1013a1 and an outer ring 1013a2, and the bearing 1013b includes an inner ring 1013b1 and an outer ring 1013b2. The inner rings 1013a1 and 1013b1 are respectively fixed to the outer peripheral surface of the shaft 1011 by press-fitting, bonding, or the like, and the outer rings 1013a2 and 1013b2 are respectively fixed to the inner peripheral surface of the cover 1012 directly or indirectly (via another member).

[0076] Each of the pair of intermediate members 1017a and 1017b has an annular shape and is fixed to an inner peripheral surface of the outer peripheral surface of the shaft 1011 by press-fitting, bonding, or the like. In the axial direction, the intermediate member 1017a is arranged on one side (upper side), and the intermediate member 1017b is arranged on the other side (lower side). The intermediate member 1017a is arranged on the other side (lower side) of the bearing 1013a and presses the inner ring 1013a1 of the bearing 1013a toward the one side (upper side) in the axial direction. The intermediate member 1017b is arranged on the one side (upper side) of the bearing 1013b and presses the inner ring 1013b1 of the bearing 1013b toward the other side (lower side) in the axial direction. The configuration may be changed so that only one of the pair of intermediate elements 1017a and 1017b is provided.

[0077] In the present invention, the magnet 1014 is a cylindrical permanent magnet having different magnetic poles (S poles and N poles) that are alternately magnetized in the circumferential direction. The magnet 1014 is fixed to the outer peripheral surface of the shaft 1011 by press-fitting, bonding, or the like. In the axial direction, the magnet 1014 is arranged between the pair of bearings 1013a and 1013b (in the present embodiment, between the pair of intermediate members 1017a and 1017b). In the present embodiment, the protective member 1018, which has a cylindrical shape, is attached to an outer peripheral surface of the magnet 1014. The protective member 1018 covers the outer peripheral surface of the magnet 1014, thereby preventing breakage or scattering of the magnet 1014. An air gap is formed between an outer peripheral surface of the protective member 1018 and the inner peripheral surface of the cover 1012.Accordingly, the magnet 1014 faces the inner peripheral surface of the cover 1012 through the protective member 1018 and the air gap. The protective member 1018 need not be provided.

[0078] The retainer 1015 has a cylindrical shape, and an end portion 1015U on one side (upper side) in the axial direction is formed in an inverted U-shape. A part of the retainer 1015 other than the end portion 1015U is disposed between an outer peripheral surface of the outer ring 1013a2 of the bearing 1013a and the inner peripheral surface of the cover 1012. That is, the retainer 1015 is fixed to the cover 1012 by being sandwiched between the outer ring 1013a2 and the cover 1012. An upper end portion of the cover 1012 is fitted into the end portion 1015U of the retainer 1015. Within the end portion 1015U of the holder 1015, an elastic member 1019 is housed on one side (upper side) in the axial direction relative to an upper end of the cover 1012. This elastic member 1019 causes the cover 1012 to be biased in the axial direction toward the other side (lower side).

[0079] In such a motor 1001, the shaft 1011, the inner rings 1013a1 and 1013b1 of the pair of bearings 1013a and 1013b, the magnet 1014, the protective member 1018, and the pair of intermediate members 1017a and 1017b rotate integrally with respect to a stator group 1070 of the motor 1001 via the balls of the pair of bearings 1013a and 1013b. That is, in the present embodiment, the shaft 1011, the inner rings 1013a1 and 1013b1 of the pair of bearings 1013a and 1013b, the magnet 1014, the protective member 1018, and the pair of intermediate members 1017a and 1017b constitute a rotor 1020 of the motor 1001. Thus, The motor 1001 operates as an internal rotor type motor. On the other hand, the stator group 1070 is a group of elements that are relatively stationary with respect to the rotation of the shaft 1011.In the present embodiment, this stator group 1070 includes the outer rings 1013a2 and 1013b2 of the pair of bearings 1013a and 1013b, the cover 1012, the holder 1015, the elastic member 1019, the stator 1040, the plurality of coils 1050, the plurality of pressure members 1060, and the yoke 1030.

[0080] Fig. 11 is a plan view illustrating the motor 1001 without the bearing device 1010, and illustrates elements (the stator 1040, the plurality of coils 1050, the plurality of pressure elements 1060, and the yoke 1030) of the stator group 1070 except for the components of the bearing device 1010 (the outer rings 1013a2 and 1013b2 of the pair of bearings 1013a and 1013b, the cover 1012, the holder 1015, the elastic member 1019, and the like). Fig. 11 are arranged outside the bearing device 1010, and therefore, the stator 1040, the plurality of coils 1050, the plurality of pressure elements 1060, and the yoke 1030 are hereinafter collectively referred to as the outer stator group 1071. This outer stator group 1071 will be described in detail below.

[0081] As in Fig. 7 to 11, the yoke 1030 of the outer stator group 1071 is a member having a cylindrical shape (annular when viewed in the axial direction), as described above, and formed of a magnetic body. The yoke 1030 includes two end surfaces (upper end surface 1034 and lower end surface 1035) in the axial direction and two side surfaces (outer peripheral part 1036 and inner peripheral part 1037) in the radial direction. In the yoke 1030, a plurality of openings 1031 (see particularly Fig. 9) penetrating in the radial direction are arranged in the circumferential direction of the yoke 1030. In the present embodiment, six openings 1031 are arranged at equal intervals (60° intervals) with respect to the shaft 1011 in the axial direction. Each of these openings 1031 is formed with the same shape and dimensions. Note that "equal" in the present description includes a deviation equal to a typical manufacturing error.

[0082] Fig. 12 is a cross-sectional view taken along the Fig. 11 illustrated line AA. Fig. 13 is a perspective view illustrating a state in which one of the plurality of stator elements 1041 shown in the following Fig. 11, from which yoke 1030 has been removed.

[0083] As in Fig. 12 and Fig. As illustrated in FIG. 13, each of the openings 1031 of the yoke 1030 extends in the axial direction from a part on the lower end surface side with respect to the upper end surface 1034 of the yoke 1030 to a part on the upper end surface 1034 side with respect to the lower end surface 1035, and in the present embodiment, is formed in a rectangular shape when viewed from the radial direction. In each of the openings 1031, a length in the axial direction and a length in the circumferential direction of the yoke 1030 are equal in the radial direction. Each of the openings 1031 includes a first inner surface 1032 on the upper end surface 1034 (one end surface) of the yoke 1030 and a second inner surface 1033 on the lower end surface (other end surface) of the yoke 1030.

[0084] As in Fig. 12, the yoke 1030 is formed of a plurality of magnetic bodies 1039 having a plate-like shape and stacked in the axial direction. Fig. 12, the magnetic bodies 1039 are omitted except for the four magnetic bodies 1039 on each of one side (upper side) in the axial direction and the other side (lower side) in the axial direction, and this omission is represented by black circles. In the present embodiment, the thicknesses of the plurality of magnetic bodies 1039 in the axial direction are the same. However, the thicknesses of the plurality of magnetic bodies 1039 in the axial direction do not need to be the same. In the present embodiment, each of the two inner surfaces of the opening 1031 in the axial direction of the yoke 1030 is a surface formed continuously with corresponding side surfaces in the axial direction of the plurality of magnetic bodies 1039 in the axial direction.The plurality of magnetic bodies 1039 excludes the magnetic body 1039 stacked furthest in the axial direction on one side (upper side) (also referred to as magnetic body 1039A for convenience) and the magnetic body 1039 stacked furthest on the other side (lower side) (also referred to as magnetic body 1039B for convenience). The first inner surface 1032 of the opening 1031 is part of a lower surface of the magnetic body 1039A, and the second inner surface 1033 of the opening 1031 is part of an upper surface of the magnetic body 1039B.Such a yoke 1030 including the plurality of openings 1031 can be manufactured, for example, by stacking the plurality of magnetic bodies 1039 except the magnetic bodies 1039A and 1039B in the axial direction, fixing them into a stacked body by caulking or an adhesive, hollowing out parts corresponding to the plurality of openings 1031 from this stacked body, and finally fixing the magnetic bodies 1039A and 1039B to one side surface and the other side surface of the stacked body in the axial direction by caulking or an adhesive.

[0085] As particularly in Fig. 9, Fig. 11 and Fig. 13, the stator 1040 includes a plurality of stator elements 1041 having the same shape and dimensions and formed of the same material. That is, the stator 1040 is composed of a plurality of stator elements 1041 spaced from each other. In the present embodiment, the stator 1040 includes six stator elements 1041. Each of the plurality of stator elements 1041 has a symmetrical shape when viewed in the axial direction. The lengths of the stator elements 1041 in the axial direction are equal to the radial direction. The stator element 1041 includes a magnetic pole portion 1042 and a spoke 1090. That is, the stator 1040 includes a plurality of magnetic pole portions 1042 and a plurality of spokes 1090. The coil 1050 is wound around each of the plurality of spokes 1090.

[0086] As in Fig. As illustrated in Figure 12, each of the plurality of stator elements 1041 is formed by a plurality of magnetic bodies 1049 having a plate-like shape and stacked in the axial direction. That is, each of the plurality of magnetic pole pieces 1042 and each of the plurality of spokes 1090 is formed by the plurality of magnetic bodies 1049 stacked in the axial direction. Fig. 12, the magnetic bodies 1049 are omitted except for the two magnetic bodies 1049 on one side in the axial direction and the three magnetic bodies 1049 on the other side in the axial direction, and this omission is represented by black circles. In the present embodiment, the thicknesses of the plurality of magnetic bodies 1049 are equal in the axial direction. In the present embodiment, the thickness of each of the plurality of magnetic bodies 1049 in the axial direction is equal to the thickness of each of the plurality of magnetic bodies 1039 constituting the yoke 1030 in the axial direction. Furthermore, in the present embodiment, the number of the plurality of magnetic bodies 1049 constituting the stator element 1041 (ie, the plurality of magnetic bodies 1049 constituting the spokes 1090) is less than the number of the plurality of magnetic bodies 1039 constituting the opening 1031 of the yoke 1030 (ie,(The plurality of magnetic bodies 1039 excluding the magnetic bodies 1039A and 1039B). In the present embodiment, the number of the plurality of magnetic bodies 1049 constituting the spokes 1090 is one less than the number of the plurality of magnetic bodies 1039 constituting the opening 1031. Accordingly, the length of the stator element 1041 (spoke 1090) in the axial direction is shorter than a length of the opening 1031 of the yoke 1030 in the axial direction.

[0087] The thicknesses of the plurality of magnetic bodies 1049 in the axial direction do not need to be the same. The thickness of each of the plurality of magnetic bodies 1049 in the axial direction does not need to be the same as the thickness of each of the plurality of magnetic bodies 1039 forming the yoke 1030 in the axial direction.

[0088] The magnetic pole part 1042 of the stator element 1041 is a part on an innermost side of the stator element 1041. The magnetic pole part 1042 is connected to an end part of the spoke 1090 on an inner side. Viewed in the axial direction, the magnetic pole part 1042 extends in the axial direction from an end part of the spoke 1090 on the inner side to the inner side and has a shape that decreases in the circumferential direction toward the inner side. An end surface 1042a of the magnetic pole part 1042 on the inner peripheral side has a shape that corresponds to a shape of an outer peripheral surface of the cover 1012 of the bearing device 1010 and is substantially in surface contact with the outer peripheral surface 1012a of the cover 1012. That is, as shown in Fig. 11, when viewing the outer stator group 1071 in the axial direction, the end surfaces 1042a of each of the plurality of magnetic pole pieces 1042 are located on a circle centered on a center of the motor 1001 (center of the shaft 1011), and as shown in Fig. As illustrated in Figure 9, the circle of these end surfaces 1042a is substantially concentric with the shaft 1011, the magnet 1014, the cover 1012, and the like constituting the bearing device 1010. The end surface 1042a of the magnetic pole portion 1042 faces the magnet 1014 through the cover 1012 of the bearing device 1010 and an air gap between the magnet 1014 and the cover 1012. Accordingly, a current supplied to the coil 1050 wound around the spoke 1090 generates a magnetic interaction between the end surface 1042a of the magnetic pole portion 1042 and the magnet 1014. As a result, the rotor 1020, including the shaft 1011, rotates with respect to the stator assembly 1070.

[0089] As in Fig. 9, the spoke 1090 of the stator element 1041 includes a first part 1043 on the inner side and a second part 1045 outside the first part 1043.

[0090] The first part 1043 of the spoke 1090 has a substantially rectangular shape when viewed in the axial direction, except for an end part 1044 on an outer side. The coil 1050 is wound around this rectangular part (except for the end part 1044 on the outer side), and an insulating part such as an insulator (not illustrated) is interposed between the coil 1050 and this rectangular part. The end part 1044 of the first part 1043 on the outer side has a shape that extends in the circumferential direction along the outer side. An end surface 1044a of the end part 1044 on the outer side has a shape corresponding to the inner peripheral part 1037 of the yoke 1030, and a length of the end surface 1044a is longer than a length of the opening 1031 of the yoke 1030 in the circumferential direction of the yoke 1030. The end surface 1044a is substantially in surface contact with the inner peripheral part 1037 of the yoke 1030.That is, each of the plurality of spokes 1090 is coupled to the plurality of magnetic pole pieces 1042 and the inner peripheral part 1037 of the yoke 1030, which has an annular shape.

[0091] The second part 1045 of the spoke 1090 includes a rectangular part 1048, which has a rectangular shape when viewed in the axial direction, and a semicircular part 1048c, which is an outwardly projecting semicircle when viewed in the axial direction. An end part of the rectangular part 1048 on the outer side is connected to an end part of a semicircular part 1048c on an inner side, and an end part of the rectangular part 1048 on an inner side is connected to the end part 1044 of the first part 1043 on the outer side. In the circumferential direction of the yoke 1030, a length of the second part 1045 is slightly shorter than a length of the above-described opening 1031 of the yoke 1030. In the radial direction, a length of the second part 1045 is longer than a length of the opening 1031. Accordingly, as particularly shown in Fig. 13 and Fig. 14, the stator element 1041 is inserted into the opening 1031 of the yoke 1030 from the inner side to the outer side of the yoke 1030, with an end part 1048ca of the semicircular part 1048c on the outer side serving as a front end, and thus the semicircular part 1048c and a part of the rectangular part 1048 pass through the opening 1031 and protrude from the yoke 1030. Fig. 14 is a plan view illustrating a state in which one of the plurality of stator elements 1041 is passed through the opening 1031.

[0092] In particular, when the stator element 1041 is inserted into the opening 1031, the end surface 1044a of the first part 1043 of the spoke 1090 finally comes into contact with the inner peripheral part 1037 of the yoke 1030, thereby further restricting the passage of the stator element 1041 to the outside. This completes the insertion of the stator element 1041 into the opening 1031. When the insertion of the stator element 1041 into the opening 1031 is completed, as shown in Fig. 12, a part of a lower end surface of the rectangular part 1048 of the second part 1045 (i.e., the lower end surface 1041D of the stator element 1041) contacts the second inner surface 1033 of the opening 1031, and a gap G is formed between an upper end surface of the rectangular part 1048 of the second part 1045 (i.e., the upper end surface 1041U of the stator element 1041) and the first inner surface 1032 of the opening 1031. In the present embodiment, a thickness of this gap G in the axial direction is equal to the thickness of a magnetic body 1039 in the axial direction and is also equal to the thickness of a magnetic body 1049 in the axial direction. As shown in Fig. As illustrated in Fig. 11, after inserting all the stator elements 1041 into the openings 1031, a space CA having a circular shape when viewed in the axial direction is formed on the inner side of the end surface 1042a of each of the plurality of stator elements 1041. The bearing device 1010 can be inserted into this space CA, for example, in the axial direction from one side to the other. On the other hand, the stator element 1041 can be removed from the yoke 1030 by removing the bearing device 1010 and then moving the stator element 1041 from the outer side to the inner side toward the space CA. Thus, each of the plurality of stator elements 1041 can be attached to and detached from the yoke 1030, which has an annular shape. That is, each of the plurality of spokes 1090 can be attached to and detached from the annular yoke 1030 having an annular shape.

[0093] As in Fig. 13 and Fig. As illustrated in FIG. 14, the spoke 1090 in each stator element 1041 includes an outer hole portion 1046 extending in the axial direction and an inner hole portion 1047 extending in the axial direction. That is, the plurality of spokes 1090 of the stator 1040 include a plurality of holes extending in the axial direction. In the present embodiment, the six spokes 1090 include six outer hole portions 1046 and six inner hole portions 1047 as a whole. Each of the plurality of outer hole portions 1046 is located outside each of the plurality of inner hole portions 1047. In the present embodiment, each of the outer hole portions 1046 and the inner hole portions 1047 extends from the upper end surface 1041U of the stator element 1041 in the axial direction to the other side (lower side).The outer hole portions 1046 and the inner hole portions 1047 may extend from the lower end surface 1041D of the stator element 1041 in the axial direction toward one side (upper side) or may penetrate the stator element 1041 in the axial direction. In the present embodiment, the outer hole portions 1046 and the inner hole portions 1047 are circular in shape when viewed in the axial direction and are formed with respective centers on a straight line passing through a center of the stator element 1041 in the circumferential direction of the yoke 1030. In the present embodiment, the outer hole portion 1046 is formed such that a region of substantially one half is positioned in the semicircular portion 1048c and a region of substantially the other half is positioned in the rectangular portion 1048c.On the other hand, the inner hole part 1047 is formed with a smaller diameter than the diameter of the outer hole part 1046 and is formed such that a region of substantially one half is positioned in the rectangular part 1048 (second part 1045) and a region of substantially the other half is positioned in the first part 1043. The diameter of the inner hole part 1047 does not have to be smaller than the diameter of the outer hole part 1046, and may be the same diameter or larger. The positional relationship and respective shapes of the inner hole parts 1047 and the outer hole parts 1046 are not limited to the positional relationship and shapes described above.For example, the positions of the inner hole parts 1047 in the radial direction may be inside the inner peripheral surface of the yoke 1030 having an annular shape in the radial direction, the inner hole parts 1047 may be fully exposed, the positions of the outer hole parts 1046 may be positions overlapping the yoke 1030 having an annular shape in the radial direction, only a part of the outer hole parts 1046 may be exposed, and the shapes of the inner hole parts 1047 and the outer hole parts 1046 may be polygonal shapes including a quadrangular shape, elliptical shapes, or the like.

[0094] In the Fig. 8 and Fig. 9, in which each of the plurality of stator elements 1041 is inserted into the openings 1031 of the yoke 1030, the outer hole parts 1046 are completely exposed from the yoke 1030 at positions adjacent to the yoke 1030 as viewed from one side in the axial direction. In the state of Fig. 8 and Fig. 9, the semicircle of the inner hole part 1047 is exposed on the inner side of the yoke 1030 from one side in the axial direction at a position adjacent to the yoke 1030. That is, in the radial direction, each of the plurality of hole parts (outer hole parts 1046 and inner hole parts 1047) is adjacent to the yoke 1030 and has an annular shape. In the present embodiment, the pressing member (element) 1060 is inserted into the inner hole part 1047 of each of the plurality of stator elements 1041. That is, in the present embodiment, six pressing members 1060 are inserted into the stators 1040.

[0095] Each of the plurality of printing elements 1060 is formed with the same shape, dimensions, and material. Fig. 15 is a perspective view illustrating the printing element 1060, and Fig. 16 is a side view illustrating the printing element 1060. As in Fig. 15 and Fig. 16, the pressing member 1060 according to the present embodiment is a wedge-like member having a semi-conical shape and including a first end surface 1061 and a second end surface 1064 having a semicircular shape when viewed in the axial direction, wherein a first side surface 1062 is a semicircular curved surface and a second side surface 1063 is an isosceles trapezoidal flat surface. The second end surface 1064 has an outer shape smaller than the outer shape of the first end surface 1061. The second side surface 1063 extends in a direction parallel to a longitudinal direction of the pressing member 1060. A ridge line 1062E of the first side surface 1062 is inclined with respect to the longitudinal direction of the pressing member 1060, i.e.with respect to the second side surface 1063, so as to approach the second side surface 1063 from the first end surface 1061 side toward the second end surface 1064 side. In the present embodiment, such a pressing member 1060 is inserted into the inner hole part 1047.

[0096] Fig. Fig. 17 is a perspective view illustrating a state at the beginning of inserting the pressure member 1060 into the inner hole part 1047. As indicated by an arrow in Fig. 17, in the present embodiment, the pressing member 1060 is inserted from one side (upper side) to the other side (lower side) in the axial direction of the inner hole part 1047. More specifically, the pressing member 1060 is inserted into the inner hole part 1047 with the second end surface 1064 of the pressing member 1060 as the leading end, the first side surface 1062 facing inward, and the second side surface 1063 facing outward. During this insertion, a part of the second side surface 1063 is brought into contact with the inner peripheral part 1037 of the yoke 1030. The term "contact" used herein includes not only contact and close contact, but also, for example, cases where a part of the pressing member 1060 is engaged with a part of the yoke 1030. In the present embodiment, a part of the second side surface 1063 is brought into line contact or surface contact with the inner peripheral part 1037.In the present embodiment, since the second side surface 1063 of the pressing member 1060 is in line or surface contact with the inner peripheral part 1037 in this way, the ridge line 1062E of the first side surface 1062 is inclined with respect to the inner peripheral part 1037, which is a side surface of the yoke 1030, so as to approach the inner peripheral part 1037 in the axial direction from one side (upper side) to the other side (lower side). Then, when the pressing member 1060 is inserted to the other side (lower side) in the axial direction of the inner hole part 1047, as shown by the arrow in FIG. Fig. 17, while maintaining a state of partial contact of the second side surface 1063 with the inner peripheral part 1037 of the yoke 1030, the first side surface 1062 is inclined with respect to the inner peripheral part 1037 as described above, which causes the stator element 1041 to be biased inward by the first side surface 1062 and to move inward when the pressing member 1060 is inserted to the lower side. As a result, the end surface 1042a of the magnetic pole part 1042 of the stator element 1041 finally comes into contact with the outer peripheral surface 1012a of the cover 1012 disposed inside the stator element 1041 (see Fig. 9). In this way, the stator element 1041 is securely positioned in the radial direction, and further insertion of the pressure element 1060 to the lower side is restricted. Fig. 7 illustrates a state where the stator element 1041 is positioned and the insertion of the pressing member 1060 is restricted at the lower side. In the present embodiment, since each of the plurality of stator elements 1041 is positioned in the radial direction by coming into contact with the outer peripheral surface 1012a of the cover 1012, a locus formed by the end surface 1042a of each magnetic pole part 1042 of the plurality of stator elements 1041, viewed in the axial direction, corresponds to a circular locus of the outer peripheral surface 1012a of the cover 1012. That is, in the present embodiment, the end surface 1042a of each of the plurality of stator elements 1041 is arranged on a circle concentric with the outer peripheral surface 1012a when viewed in the axial direction, and the arrangement of the plurality of stator elements 1041 having high roundness is achieved.

[0097] In the present embodiment, the position in the axial direction of the first end surface 1061 of the pressing member 1060 is in the state of Fig. 7, in which the insertion of the pressing member 1060 is restricted to the lower side, the same as the position in the axial direction of an upper surface 1051 of the coil 1050 wound around the spoke 1090 or is located between the upper surface 1051 of the coil 1050 and the upper end surface 1034 of the yoke 1030. Thus, for example, when a member such as a substrate is located on one side (upper side) in the axial direction with respect to the upper surface 1051 of the coil 1050, such a member such as the substrate can be arranged without interference by the pressing member 1060.

[0098] Furthermore, in the state of Fig. 7, the stator element 1041 inserted into the opening 1031 is pressed by the pressure element 1060 in a state in which it is positioned in the radial direction and thus also biased in the axial direction toward the other side (lower side), as shown by an arrow in Fig. 12. That is, the plurality of magnetic bodies 1049 constituting the spokes 1090 are biased from the upper end surface 1034 side (one end surface) toward the lower end surface 1035 side (other end surface) of the yoke 1030.Accordingly, as a result of the stator element 1041 being inserted into the opening 1031 being biased toward the other side (lower side) in the axial direction, in other words, as a result of the plurality of magnetic bodies 1049 constituting the spokes 1090 being biased from the first inner surface 1032 (inner surface on one end surface side) toward the second inner surface 1033 (inner surface on the other end surface side) of the opening 1031 of the yoke 1030, the stator element 1041 is positioned in the axial direction with a lower surface of the stator element 1041 in surface contact with the upper surface of the magnetic body 1039B of the yoke 1030 (second inner surface 1033 of the opening 1031).As described above, the thickness in the axial direction of each of the plurality of magnetic bodies 1049 constituting the stator element 1041 (spoke 1090) is the same as the thickness in the axial direction of each of the plurality of magnetic bodies 1039 constituting the yoke 1030, and thus the position of each of the plurality of magnetic bodies 1049 and the position of each of the plurality of magnetic bodies 1039 in the axial direction are the same. Specifically, in the circumferential direction of the yoke 1030, each of the plurality of magnetic bodies 1039 constituting the spokes 1090 faces any one of the plurality of magnetic bodies 1049 constituting the yoke 1030 without being displaced in the axial direction.In this way, in the present embodiment, a boundary position between a pair of magnetic bodies 1049 and 1049 adjacent to each other in the axial direction and a boundary position between a pair of magnetic bodies 1039 and 1039 adjacent to each other in the axial direction are the same. As described above, in the present embodiment, the number of the plurality of magnetic bodies 1049 constituting the spokes 1090 is one less than the number of the plurality of magnetic bodies 1039 constituting the opening 1031 of the plurality of magnetic bodies 1039 constituting the yoke 1030, and the thickness of the gap G in the axial direction is thus equal to the thickness of one magnetic body 1049 and is equal to the thickness of one magnetic body 1039.

[0099] As described above, the motor 1001 according to the present embodiment includes the yoke 1030 having an annular shape including both end surfaces (upper end surface 1034 and lower end surface 1035) in the axial direction, and the stator 1040. The stator 1040 of this motor 1001 includes the plurality of magnetic pole pieces 1042, the plurality of spokes 1090 coupled to the plurality of magnetic pole pieces 1042 and the inner peripheral part 1037 of the yoke 1030 having an annular shape, and the plurality of coils 1050 wound around the plurality of spokes 1090.Then, in the motor 1001, each of the plurality of spokes 1090 can be attached to and detached from the yoke 1030, the yoke 1030 and each of the plurality of spokes 1090 are formed of the plurality of magnetic bodies 1039 and 1049 stacked in the axial direction, and the plurality of magnetic bodies 1049 constituting the spokes 1090 are biased from the one end surface side (upper end surface 1034) to the other end surface side (lower end surface 1035) of the two end surfaces (upper end surface 1034 and lower end surface 1035) of the yoke 1030.

[0100] In such a motor 1001, each of the plurality of spokes 1090 (i.e., stator elements 1041) can be attached to and detached from the yoke 1030, so that the coil 1050 can be wound around the spoke 1090 before the spoke 1090 is inserted into the yoke 1030. That is, the coil 1050 can be wound around the spoke 1090 without interference with another spoke 1090 adjacent in the circumferential direction. Accordingly, the coil 1050 can be wound with a large space requirement, and the motor 1001 is a motor in which the coil is wound with a large space requirement.

[0101] In the motor 1001, the plurality of magnetic bodies 1049 constituting the spokes 1090 are biased from one end surface (upper end surface 1034) of the two end surfaces (upper end surface 1034 and lower end surface 1035) of the yoke 1030 toward the other end surface (lower end surface 1035) as described above, the position of each of the plurality of magnetic bodies 1049 and the position of each of the plurality of magnetic bodies 1039 are thus the same in the axial direction in each of the plurality of openings 1031 of the yoke 1030, and the position of the boundary between the pair of magnetic bodies 1049 and 1049 adjacent to each other in the axial direction and the position of the boundary between the pair of magnetic bodies 1039 and 1039 adjacent to each other are the same in the axial direction.In such a configuration, when a magnetic flux is generated in each of the plurality of magnetic bodies 1049 constituting the spokes 1090 by the coil 1050 wound around the spoke 1090, these magnetic fluxes can be transmitted to the plurality of magnetic bodies 1039 constituting the yoke 1030 without being obstructed by the boundary between the pair of adjacent magnetic bodies 1039 and 1039. Accordingly, the motor 1001 suppresses a deviation of a magnetic path and can achieve, for example, high efficiency.

[0102] Even if the thicknesses of each of the plurality of magnetic bodies 1039 are not equal, the thicknesses of the plurality of magnetic bodies 1049 are not equal, or the thicknesses of each of the plurality of magnetic bodies 1049 in the axial direction and the thicknesses of each of the plurality of magnetic bodies 1039 constituting the yoke 1030 in the axial direction are not equal, the plurality of magnetic bodies 1049 constituting the spokes 1090 are securely positioned in the openings 1031 of the plurality of magnetic bodies 1049 in the axial direction by being biased from one end surface (upper end surface 1034) of the two end surfaces (upper end surface 1034 and lower end surface 1035) of the yoke 1030 toward the other end surface (lower end surface 1035), as long as the degree of unevenness is within a normally expected range, and thus the position of the boundary between the pair of magnetic bodies 1049, 1049,that are adjacent to each other in the axial direction, and the position of the boundary between the pair of magnetic bodies 1039 and 1039 that are adjacent to each other in the axial direction are substantially the same. This suppresses magnetic path deviation and can achieve, for example, high efficiency.

[0103] In the present embodiment, the side surfaces of the plurality of magnetic bodies 1039 having a plate-like shape and the plurality of magnetic bodies 1049 forming the opening 1031 are in Fig. 12A illustrates. When each of the magnetic bodies 1039 and 1049 is formed, a magnetic body is placed on a mold (so-called die), pressed from above by another mold (so-called punch) to apply a force, and cut the magnetic body to a predetermined size to obtain the magnetic bodies 1039 and 1049. The side surfaces of the magnetic bodies 1039 and 1049 obtained by pressing in this way include curved surfaces WF (so-called sags), shear surfaces XF (cut surfaces) extending in the axial direction, fracture surfaces YF depressed toward the inner sides of the magnetic bodies 1039 and 1049, and portions ZF protruding from the fracture surfaces (so-called burrs).Of the curved surfaces WF, the shearing surfaces XF, the fracture surfaces YF, and the protruding parts ZF that form the side surfaces of the plurality of magnetic bodies 1039 and 1049, the shearing surface XF of the magnetic body 1039 and the shearing surface XF of the magnetic body 1049 contact each other and form the magnetic path. The shearing surface XF of each of the magnetic bodies 1039 and 1049 occupies 30% to 50% of the total side surfaces of the magnetic bodies 1039 and 1049. Therefore, the thicknesses of the magnetic bodies 1039 and 1049 are preferably substantially equal to the extent that the shearing surfaces XF of each of the magnetic bodies 1039 and 1049 can contact each other. Seventh embodiment

[0104] Next, a motor 1002 according to the seventh embodiment will be described. Fig. 18 is a perspective view illustrating the motor 1002 according to the present embodiment. As shown in Fig. As illustrated in Fig. 18, the motor 1002 according to the present embodiment has substantially the same configuration as the configuration of the motor 1001 according to the sixth embodiment, but differs from the motor 1001 according to the sixth embodiment mainly in the configuration of the bearing device, the configuration of the pressing member, and the insertion position of the pressing member. Accordingly, only these differences will be described below. The other embodiments are denoted by the same reference numerals as those of the sixth embodiment, and the descriptions of the other embodiments will be omitted.

[0105] As in Fig. As illustrated in Fig. 18, a bearing device 1100 of the motor 1002, unlike the bearing device 1010 of the motor 1001, does not include a cover like the cover 1012. Accordingly, in the motor 1002, the magnet 1014, which has a cylindrical shape, and the protective member 1018 are exposed, and the protective member 1018 faces the end surface 1042a of the magnetic pole part 1042 of the stator element 1041 through an air gap. In the motor 1002, the outer rings 1013a2 and 1013b2 of the pair of bearings 1013a and 1013b and the like (i.e., members constituting the stator group 1070) may be directly or indirectly fixed, for example, to a housing (not illustrated).

[0106] Also in the motor 1002, similar to the motor 1001, the spokes 1090 (stator elements 1041) are inserted into the respective plurality of openings 1031 of the yoke 1030. In the motor 1002, similar to the motor 1001, the plurality of magnetic bodies 1049 constituting the spokes 1090 are biased by the pressing member from the upper end surface 1034 side toward the lower end surface 1035 side of the yoke 1030. However, in the motor 1002, a pressing member 1160 different from the pressing member 1060 is used as the pressing member, and unlike the motor 1001, the pressing member 1160 is inserted into the outer hole part 1046 of the spoke 1090 (stator element 1041).

[0107] Fig. 19 is a perspective view illustrating the pressure element 1160, and Fig. 20 is a view from below. As in Fig. 19 and Fig. 20, the pressing member 1160 has a shape obtained by cutting a part of the upper surface of a truncated cone including an upper surface having a large diameter and a lower surface having a small diameter, parallel to the longitudinal direction of the pressing member 1160. That is, the pressing member 1160 includes a first end surface 1161 on one side and a second end surface 1164 on the other side in the longitudinal direction of the pressing member 1160, a first surface 1162 that occupies most of the side surface of the pressing member 1160, and a second surface 1163 that is a surface of the side surface of the pressing member 1160 except for the first surface 1162. The second end surface 1164 has a circular shape when the pressing member 1160 is viewed from the longitudinal direction.When the pressure element 1160 is viewed in the longitudinal direction, the first end surface 1161 has a shape obtained by cutting off a part of a circle having a larger diameter than the diameter of the second end surface 1164 and a larger area than an area of ​​the second end surface 1164. The first surface 1162 is a curved surface of a surface obtained by removing, in a direction parallel to the longitudinal direction of the pressure element 1160, from the first end surface 1161 a part of a conical surface having a diameter decreasing from the first end surface 1161 toward the second end surface 1164. The second end surface 1163 is a flat surface parallel to the longitudinal direction of the pressure element 1160 of the removed surface.When viewing the pressure member 1160 from the side, the ridge line 1162E of the first surface 1162 is inclined with respect to the second surface 1163 parallel to the longitudinal direction of the pressure member 1160, so as to approach a central axis of the pressure member 1160 from the first end surface 1161 toward the second end surface 1164. The central axis of the pressure member 1160 is a straight line passing through the centers of the first end surface 1161 and the second end surface 1164 and extending in the longitudinal direction of the pressure member 1160.

[0108] In the engine 1002, as in Fig. 18, such a plurality of (six in the present embodiment) pressure elements 1160 are respectively inserted into the plurality of (six in the present embodiment) outer hole parts 1046. In Fig. 18, only one pressing member 1160 is illustrated for simplicity. Specifically, the pressing member 1160 is inserted from one side (upper side) to the other side (lower side) in the axial direction of the outer hole part 1046. More specifically, the pressing member 1160 is inserted into the outer hole part 1046 with the second end surface 1164 of the pressing member 1160 as the leading end, the second surface 1163 facing inward, and the first surface 1162 facing outward. During this insertion, a part of the second surface 1163 is brought into contact with the outer peripheral part 1036 of the yoke 1030. The term "contact" used herein includes not only contact and close contact, but also, for example, cases where a part of the pressing member 1160 is engaged with a part of the yoke 1030.In the present embodiment, a part of the second surface 1163 is brought into line contact or surface contact with the outer peripheral part 1036. Since the second surface 1163 of the pressing member 1160 in the present embodiment is in line contact or surface contact with the outer peripheral part 1036 in this way, the ridge line 1162E of the first surface 1162 is inclined with respect to the outer peripheral part 1036, which is a side surface of the yoke 1030, so as to approach the outer peripheral part 1036 in the axial direction from one side (upper side) to the other side (lower side).Then, when the pressing member 1160 is inserted toward the lower side of the outer hole part 1046 while maintaining a state of partial contact of the second surface 1163 with the outer peripheral part 1036 of the yoke 1030, the first surface 1162 is inclined with respect to the outer peripheral part 1036 as described above, whereby the stator element 1041 is biased outward by the first surface 1162 and moves outward as the pressing member 1160 is inserted toward the lower side. As a result, the end surface 1044a (see FIG. Fig. 14) of the end part 1044 on the outer side of the first part 1043 of the spoke 1090 finally comes into contact with the inner peripheral part 1037 of the yoke 1030. Thus, the stator element 1041 is securely positioned in the radial direction, and further insertion of the pressing element 1160 to the lower side is restricted. Fig. Fig. 18 illustrates a state in which the stator element 1041 is positioned and the insertion of the pressure element 1060 is restricted at the lower side. In the present embodiment, in this state of Fig. 18, the position in the axial direction of the first end surface 1161 of the pressure member 1160 is the same as the position in the axial direction of the upper surface 1051 of the coil 1050 wound around the spoke 1090, or is located between the upper surface 1051 of the coil 1050 and the upper end surface 1034 of the yoke 1030.

[0109] Furthermore, in the state of Fig. 18, the stator element 1041 inserted into the opening 1031 is pressed by the pressure element 1160 in a state in which it is positioned in the radial direction and thus biased in the axial direction toward the other side (lower side), as shown by the arrow in Fig.12. That is, the plurality of magnetic bodies 1049 constituting the spokes 1090 are biased from the upper end surface 1034 side (one end surface) toward the lower end surface 1035 side (other end surface) of the yoke 1030.Accordingly, as a result, the stator element 1041 inserted into the opening 1031 is biased toward the lower side, in other words, as a result of the plurality of magnetic bodies 1049 constituting the spokes 1090 being biased from the first inner surface 1032 (inner surface on one end surface side) toward the second inner surface 1033 (inner surface on the other end surface side) of the opening 1031 of the yoke 1030, the stator element 1041 is positioned in the axial direction with the lower surface of the stator element 1041 in surface contact with the upper surface of the magnetic body 1039B of the yoke 1030 (second inner surface 1033 of the opening 1031).

[0110] As described above, the motor 1002 according to the present embodiment includes the yoke 1030 having an annular shape including both end surfaces (upper end surface 1034 and lower end surface 1035) in the axial direction, and the stator 1040. The stator 1040 of this motor 1002 includes the plurality of magnetic pole pieces 1042, the plurality of spokes 1090 coupled to the plurality of magnetic pole pieces 1042 and the inner peripheral part 1037 of the yoke 1030 having an annular shape, and the plurality of coils 1050 wound around the plurality of spokes 1090.Then, in the motor 1002, each of the plurality of spokes 1090 can be attached to and detached from the yoke 1030, the yoke 1030 and each of the plurality of spokes 1090 are formed of the plurality of magnetic bodies 1039 and 1049 stacked in the axial direction, and the plurality of magnetic bodies 1049 constituting the spokes 1090 are biased from one end surface side (upper end surface 1034) to the other end surface side (lower end surface 1035) of the two end surfaces (upper end surface 1034 and lower end surface 1035) of the yoke 1030.

[0111] In such a motor 1002, each of the plurality of spokes 1090 (i.e., stator elements 1041) can be attached to and detached from the yoke 1030 so that the coil 1050 can be wound around the spoke 1090 before the spoke 1090 is inserted into the yoke 1030. Accordingly, as in the motor 1001, the coil 1050 can be wound with a high space requirement, and the motor 1002 is a motor in which the coil is wound with a high space requirement.

[0112] As described above, the motor 1002 causes the plurality of magnetic bodies 1049 constituting the spokes 1090 to be biased from one side of one end surface (upper end surface 1034) toward the other end surface (lower end surface 1035) of the two end surfaces (upper end surface 1034 and lower end surface 1035) of the yoke 1030, and thus, similar to the motor 1001, the magnetic flux generated by the coil 1050 in each of the plurality of magnetic bodies 1049 can be transmitted to the plurality of magnetic bodies 1049 without being hindered by the boundary between the pairs of magnetic bodies 1039 and 1039 adjacent to each other in the axial direction among the plurality of magnetic bodies constituting the yoke 1030. Accordingly, the motor 1002 suppresses a deviation of the magnetic path and can achieve, for example, high efficiency.

[0113] Although the above-described embodiment exemplifies another motor according to the present invention, the present invention is not limited to this example.

[0114] Although an example of the plurality of magnetic bodies 1049 constituting the spokes 1090 being biased from one side to the other side in the axial direction has been described in the above-described embodiment, the plurality of magnetic bodies 1049 may be biased from the other side to the one side in the axial direction, for example.

[0115] The pressing member described in the above-described embodiments is not limited to the pressing members 1060 and 1160, as long as the plurality of magnetic bodies 1049 constituting the spokes 1090 can be biased from one end surface side of the two end surfaces (upper end surface 1034 and lower end surface 1035) of the yoke 1030 toward the other end surface side, and a pressing member having a different shape or configuration can be used. The plurality of magnetic bodies 1049 constituting the spokes 1090 can be biased from one end surface side of the two end surfaces (upper end surface 1034 and lower end surface 1035) of the yoke 1030 toward the other end surface side without using the pressing member.

[0116] Furthermore, the motor according to the present invention can be appropriately modified, and the shapes, dimensions, and combinations of various configurations can be changed by a person skilled in the art according to previously known knowledge. These modifications are, of course, included within the scope of the present invention as long as these modifications continue to include the configurations of the present invention. List of reference symbols 100 engine, 112, 212 Magnet, 113a first camp, 113b second camp, 114, 314, 414 cover, 115, 415 holders, 115d, 415d accommodation part, 116, 416 elastic element, 117a, 117b pressure element, 118 protective element, 119 spacers, 120 spool, S wave, 1001, 1002 engine, 1030 yoke, 1031 opening, 1032 first inner surface (inner surface), 1033 second inner surface (inner surface), 1034 upper end surface (end surface), 1035 lower end surface (end surface), 1036 outer peripheral part (side surface), 1037 inner peripheral part (side surface), 1039 magnetic bodies, 1040 stator, 1042 magnetic pole piece, 1046 outer hole part (hole part), 1047 inner hole part (hole part), 1049 magnetic bodies, 1050 coil, 1060, 1160 pressure element (element), 1090 spoke. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 04-82425

[0003] JP 2012-105397 A

[0067]

Claims

[1] Engine, comprising: a wave; a magnet; a coil; a first bearing arranged on one side of an end part of the shaft in the axial direction; a second bearing arranged on one side of the other end part of the shaft in the axial direction; a cover fixed to the second bearing and arranged inside the spool in a radial direction; a holder fixed to the first bearing; and an elastic element held by the holder, wherein the elastic member is arranged between the cover and the holder in a longitudinal direction of the shaft. [2] The motor according to claim 1, wherein the magnet is disposed within the cover in the radial direction. [3] The motor according to claim 1 or 2, wherein the holder includes an accommodating portion in which the elastic member is accommodated. [4] The motor according to claim 1 or 2, wherein the elastic member biases the holder in the axial direction. [5] Engine according to claim 1 or 2, comprising a pressure element disposed between the magnet and the first bearing and configured to press an inner ring of the first bearing. [6] The motor of claim 5, wherein the pressure element is a balancing element configured to adjust a rotational balance of the shaft. [7] The motor according to claim 1 or 2, wherein the cover covers the first bearing and the second bearing in the radial direction. [8] Engine according to claim 1 or 2, comprising a protective member configured to cover an outer side of the magnet in the radial direction. [9] The motor according to claim 1 or 2, wherein a size of the magnet in the radial direction is larger than a size of the first bearing or the second bearing in the radial direction. [10] The motor according to claim 1 or 2, wherein the cover is fixed to the second bearing via a spacer. [11] The motor according to claim 1, wherein the elastic member is arranged on the side of the one end part of the shaft with respect to the first bearing in the axial direction. [12] The motor according to claim 11, wherein the elastic member is positioned between the first bearing and the one end portion of the shaft in the axial direction. [13] The motor according to claim 12, wherein the elastic member is positioned at a predetermined distance from the first bearing toward the side of the one end part of the shaft in the axial direction. [14] The motor according to claim 13, wherein the elastic member is located between an end part on one side of the cover and the holder in the axial direction. [15] The motor according to claim 14, wherein a size of the elastic member in the radial direction is larger than a size of the cover in the radial direction. [16] Engine, comprising: an annular yoke including two end surfaces in an axial direction; and a stator including a plurality of magnetic pole pieces, a plurality of spokes coupled to the plurality of magnetic pole pieces and an inner peripheral portion of the annular yoke, and a plurality of coils wound around the plurality of spokes, wherein each of the plurality of spokes is attachable to and detachable from the annular yoke, the annular yoke and each of the plurality of spokes is formed of a plurality of magnetic bodies stacked in the axial direction, and the plurality of magnetic bodies forming the spokes are biased from one side of one end surface toward one side of the other end surface of the two end surfaces of the annular yoke. [17] The motor of claim 16, wherein the plurality of magnetic bodies forming the spokes are biased in a radial direction. [18] Engine according to claim 16 or 17, wherein the annular yoke includes a plurality of openings arranged in a circumferential direction, each of the plurality of openings includes an inner surface on the side of one end surface of the annular yoke and an inner surface on the side of the other end surface of the annular yoke, the plurality of spokes extend in the radial direction and pass through the plurality of openings, and the plurality of magnetic bodies constituting the spokes are biased from the inner surface on the side of one end surface of the annular yoke toward the inner surface on the side of the other end surface of the annular yoke. [19] The motor according to claim 18, wherein the number of the plurality of magnetic bodies forming the spokes is less than the number of a plurality of magnetic bodies forming the plurality of openings of the plurality of magnetic bodies forming the annular yoke. [20] Engine according to claim 16 or 17, wherein the plurality of spokes includes a plurality of hole portions extending in the axial direction, and Elements inserted into the plurality of hole parts preload the plurality of magnetic bodies forming the spokes. [21] The motor according to claim 20, wherein each of the plurality of hole parts is adjacent to the annular yoke in the radial direction. [22] The motor of claim 21, wherein each of the elements contacts a side surface of the annular yoke. [23] The motor of claim 21, wherein each of the elements includes a side surface inclined relative to a side surface of the annular yoke. [24] A motor according to claim 16 or 17, wherein a thickness in the axial direction of each of the plurality of magnetic bodies constituting the spokes is equal to the thickness in the axial direction of each of the plurality of magnetic bodies constituting the annular yoke.

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