Motor

Abstract

To provide a motor whose lifetime is long.SOLUTION: A motor comprises: a shaft S; magnets 112 and 212; a coil 120; a first bearing 113a disposed at a side of one end S1 of the shaft S in an axial X direction; a second bearing 113b disposed at a side of the other end S2 of the shaft S in the axial X direction; a holder 115 fixed to the first bearing 113a; a cover 114 fixed to the first bearing 113a via the holder 115 in a radial direction; and an elastic member 116 disposed inside of the holder 115 in the radial direction. In the axial X direction, the elastic member 116 is connected to the holder 115 and the first bearing 113a.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a motor. [Background technology]

[0002] Conventionally, there is known a motor equipped with a bearing device in which bearings are arranged on both ends of a shaft and the two bearings are preloaded in a direction in which they move away from each other in the axial direction. For example, Patent Document 1 discloses a bearing device equipped with a preload spring. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 6-84765 Summary of the Invention [Problem to be solved by the invention]

[0004] In this type of motor, for example, there is a demand for extending the life of the motor. An example of an object of the present invention is to provide a motor with a long life. [Means for solving the problem]

[0005] The motor of the present invention comprises a shaft, a magnet, a coil, a first bearing arranged on one end side of the shaft in the axial direction, a second bearing arranged on the other end side of the shaft in the axial direction, a holder fixed to the first bearing, a cover fixed to the first bearing via the holder in the radial direction, and an elastic member arranged inside the holder in the radial direction, and the elastic member is connected to the holder and the first bearing in the axial direction. [Brief description of the drawings]

[0006] [Figure 1] 1 is a cross-sectional view of a motor according to a first embodiment, which is an example of the present invention. [Diagram 2] 1 is a cross-sectional view of only a bearing device in a motor according to a first embodiment, which is an example of the present invention. [Diagram 3] 10 is a cross-sectional view of only a bearing device in a motor according to a second embodiment of the present invention, which is an example of the present invention. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] In the description of each embodiment of the present invention, for convenience of description, the direction of the arrow ab along the axis X in each drawing is referred to as the axial direction. In the axial direction, the direction of the arrow a (direction from the second bearing 113b to the first bearing 113a) is referred to as the lower side or one side. In the axial direction, the direction of the arrow b (direction from the first bearing 113a to the second bearing 113b) along the axis X is referred to as the upper side or the other side. In addition, the direction perpendicular to the axial direction and approaching or moving away from the axis X (direction of the arrow cd) is referred to as the radial direction, the direction of the arrow c away from the axis X is referred to as the outer side or one side, and the direction of the arrow d approaching the axis X is referred to as the inner side or the other side.

[0008] [First embodiment] A first embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a cross-sectional view of a motor 100 according to this embodiment, cut along a plane including an axis X. Fig. 2 is a view showing only a bearing device 110 in Fig. 1.

[0009] As shown in FIG. 1, the motor 100 includes a bearing device 110, a coil 120, a magnetic body 130, a case 140, and a cover 150. In this embodiment, the magnetic body 130 is composed of a plurality of magnetic bodies (electromagnetic steel plates) stacked in the axial direction. The case 140 is a tubular member that is open on the other side in the axial direction (arrow b direction). The case 140 includes a tubular portion (cylindrical portion) 141, a bottom portion 142, and an annular protruding portion 143. The cylindrical portion 141 is a cylindrical portion having an axis X as a central axis. The bottom portion 142 is an annular flat plate portion that extends from an end portion on one side in the axial direction (arrow a direction) of the cylindrical portion 141 to an inner side in the radial direction (arrow d direction). The protruding portion 143 is a cylindrical portion that extends from an end portion on the inner side in the radial direction (arrow d direction) of the bottom portion 142 to the other side in the axial direction (arrow b direction). The dimension (length) of the cylindrical portion 141 is greater than the dimension (length) of the protruding portion 143 in the axial direction.

[0010] The lid 150 is a lid-like member that covers the opening on the other side (arrow b direction) in the axial direction of the cylindrical portion 141 of the case 140, and has a flat plate portion 151, an outer peripheral portion (engagement portion) 152, and an inner peripheral portion (convex portion) 153. The flat plate portion 151 is an annular portion with the axis X as the central axis. In the radial direction, the flat plate portion 151 has the same or approximately the same dimensions (inner diameter and outer diameter) as the bottom portion 142 of the case 140. The engagement portion 152 is an annular portion that protrudes to one side in the axial direction (arrow a direction) slightly inward (arrow d direction) from the end portion on the outer side (arrow c direction) in the radial direction of the flat plate portion 151. The convex portion 153 is a cylindrical portion that protrudes to one side in the axial direction (arrow a direction) from the end portion on the inner side (arrow d direction) in the radial direction of the flat plate portion 151. In the axial direction, the length of the engagement portion 152 is approximately the same as the length of the protrusion 153 .

[0011] The engaging portion 152 of the lid 150 engages with the end (outer peripheral end) of the cylindrical portion 141 of the case 140 on the other side in the axial direction (arrow b direction). In the radial direction, the outer dimension (outer diameter) of the engaging portion 152 of the lid 150 is the same or approximately the same as the inner dimension (inner diameter) of the cylindrical portion 141 of the case 140. The engaging portion 152 of the lid 150 is inserted into the inner side in the radial direction (arrow d direction) of the end of the cylindrical portion 141 of the case 140 on the other side in the axial direction (arrow b direction). The engaging portion 152 of the lid 150 is fixed to the cylindrical portion 141 of the case 140 by adhesion, press fitting, or the like. Therefore, the lid 150 is fixed to the case 140 via the engaging portion 152.

[0012] The inner diameter (diameter of the inside) of the protruding portion 143 of the case 140 is the same or approximately the same as the inner diameter (diameter of the inside) of the convex portion 153 of the lid 150. In the radial direction, the outer surface (outer surface) of a cylindrical cover 114 (described later) of the bearing device 110 is fixed to the inner surface (inner circumferential surface) of the protruding portion 143 of the case 140 and the inner surface (inner circumferential surface) of the convex portion 153 of the lid 150 by adhesive or the like. The coil 120 and the magnetic body 130 are accommodated in a cylindrical space defined by the case 140, the lid 150, and the cover 114 of the bearing device 110 and having the axis X as the central axis. Therefore, in the radial direction, the cover 114 of the bearing device 110 is disposed inside the coil 120 (in the direction of the arrow d).

[0013] The magnetic body 130 is formed, for example, by a laminate in which a plurality of electromagnetic steel sheets made of soft magnetic material are stacked in the axial direction. In the radial direction, the magnetic body 130 is connected to the inner surface (arrow d direction) of the cylindrical portion 141 of the case 140, and extends inward (arrow d direction) to the vicinity of the cover 114 of the bearing device 110. Alternatively, the magnetic body 130 may be connected and fixed to the cover 114 of the bearing device 110, or may be connected and fixed to both the cylindrical portion 141 of the case 140 and the cover 114 of the bearing device 110. In the motor 100 according to this embodiment, six magnetic bodies 130 are provided radially arranged at equal angular intervals in the circumferential direction (direction of rotation around the axis X). However, the number of magnetic bodies 130 is not limited to six, and may be any number according to the design of the motor 100. A coil 120 is wound around each magnetic body 130 via an insulator (not shown).

[0014] The coil 120 and the magnetic body 130 constitute the stator 10 of the motor 100. As described above, the magnetic body 130 is fixed to the cover 114 of the bearing device 110 directly or via the case 140 and the lid 150. As a result, the cover 114 of the bearing device 110 is fixed to the stator 10 directly or indirectly. In other words, the cover 114 of the bearing device 110 is one of the stationary members that is stationary compared to rotors such as the rotating shaft S and the magnet 112. Note that the stationary member does not have to be a completely stationary member, and includes members that are stationary compared to rotors such as the rotating shaft S and the magnet 112.

[0015] As shown in FIG. 2, the bearing device 110 includes a shaft S, a magnet 112, a first bearing 113a, a second bearing 113b, a cylindrical cover 114, a holder 115, and an elastic member 116. In the radial direction, the shaft S, the magnet 112, the first bearing 113a, the second bearing 113b, and the elastic member 116 are disposed inside the cover 114. That is, the cover 114 is a sleeve that covers the shaft S, the magnet 112, the first bearing 113a, the second bearing 113b, and the elastic member 116 in the radial direction. The cover 114 includes a first end 114a on the first bearing 113a side (one side in the axial direction, the direction of the arrow a) and a second end 114b on the second bearing 113b side (the other side in the axial direction, the direction of the arrow b). The cover 114 is formed of, for example, ceramic. However, the cover 114 may be made of other materials, such as non-magnetic metals or resins.

[0016] The shaft S is a rod-like member having a cylindrical or substantially cylindrical shape extending in the axial direction. The shaft S has one end S1 on one side in the axial direction (the direction of the arrow a) and the other end S2 on the other side in the axial direction (the direction of the arrow b). In the axial direction, the first bearing 113a is disposed on the one end S1 side of the shaft S. In addition, the second bearing 113b is disposed on the other end S2 side of the shaft S in the axial direction.

[0017] The first bearing 113a is a ball bearing having an inner ring 113ai, an outer ring 113ao, and rolling elements. The first bearing 113a is not limited to this type of ball bearing, and may be various other bearings, such as a ball bearing having an outer ring and a ball fitted into a recess on the surface (outer peripheral surface) on the outer side in the radial direction of the shaft (arrow c direction). The inner ring 113ai of the first bearing 113a is press-fitted or bonded to the surface (outer peripheral surface) on the outer side in the radial direction (arrow c direction) of the shaft S. As a result, the inner ring 113ai of the first bearing 113a is fixed to the shaft S.

[0018] The second bearing 113b has the same dimensions and configuration as the first bearing 113a. The second bearing 113b is a ball bearing having an inner ring 113bi, an outer ring 113bo, and rolling elements. The second bearing 113b is not limited to this type of ball bearing, and may be, for example, a sleeve bearing, a ball bearing having a ball and an outer ring fitted in a recess on the surface (outer peripheral surface) on the outer side in the radial direction of the shaft (arrow c direction), or other various bearings. The inner ring 113bi of the second bearing 113b is pressed or bonded to the surface (outer peripheral surface) on the outer side in the radial direction (arrow c direction) of the shaft S. As a result, the inner ring 113bi of the second bearing 113b is fixed to the shaft S.

[0019] In the radial direction, the second end 114b of the cylindrical cover 114 is fixed to the outside (arrow c direction) of the outer ring 113bo of the second bearing 113b via an annular spacer 119. In the axial direction, the dimension of the spacer 119 is the same or approximately the same as the dimension of the second bearing 113b. However, the dimension of the spacer 119 in the axial direction may be different from that of the second bearing 113b. In the radial direction, the inner diameter of the spacer 119 is the same or approximately the same as the outer diameter of the outer ring 113bo of the second bearing 113b, and the outer diameter of the spacer 119 is the same or approximately the same as the inner diameter of the cover 114. The radially outer surface (direction of arrow c) of the outer ring 113bo of the second bearing 113b is fixed to the radially inner surface (direction of arrow d) of the spacer 119 by press-fitting or bonding, and the radially outer surface (direction of arrow c) of the spacer 119 is fixed to the radially inner surface (direction of arrow d) of the cover 114 by press-fitting or bonding. The second bearing 113b supports the shaft S rotatably relative to the cover 114.

[0020] A cylindrical portion 115a of a holder 115, which will be described later, is fixed to the outer side (arrow c direction) of an outer ring 113ao of the first bearing 113a in the radial direction. The first bearing 113a supports the shaft S rotatably relative to the holder 115.

[0021] The holder 115 has a three-dimensional shape obtained by rotating a substantially S-shaped cross section around the axis X. In other words, the holder 115 has an opening and a bottom with a circular hole at the center, and has a cup-like three-dimensional shape with the opening facing one side (arrow a direction) and the bottom facing the other side (arrow b direction) in the axial direction. The holder 115 is made of metal such as aluminum, copper, iron, etc. However, the holder 115 may be made of other materials such as resin. The holder 115 may be made of a material softer than the cover 114. The holder 115 has a cylindrical portion 115a, an inner peripheral portion 115b, and an outer peripheral portion 115c.

[0022] The cylindrical portion 115a of the holder 115 is a cylindrical portion extending in the axial direction. In the axial direction, the dimension of the cylindrical portion 115a of the holder 115 is larger than the dimension of the first bearing 113a. In the radial direction, the thickness of the cylindrical portion 115a of the holder 115 is the same or approximately the same as the thickness of the spacer 119. In addition, in the radial direction, the inner diameter and the outer diameter of the cylindrical portion 115a of the holder 115 are the same or approximately the same as the inner diameter and the outer diameter of the spacer 119.

[0023] In the radial direction, the inner diameter of the cylindrical portion 115a of the holder 115 is the same or approximately the same as the outer diameter of the outer ring 113ao of the first bearing 113a, and the outer diameter of the cylindrical portion 115a is the same or approximately the same as the inner diameter of the cover 114. The outer surface (arrow c direction) of the outer ring 113ao of the first bearing 113a and the inner surface (arrow d direction) of the cylindrical portion 115a of the holder 115 in the radial direction are fixed by press-fitting or adhesive bonding, and the outer surface (arrow c direction) of the cylindrical portion 115a of the holder 115 and the inner surface (arrow d direction) of the cover 114 in the radial direction are fixed by press-fitting or adhesive bonding. That is, the cover 114 is fixed to the first bearing 113a via the holder 115 in the radial direction.

[0024] The inner peripheral portion 115b of the holder 115 is an annular portion that extends from the end portion on the other axial side (direction of arrow b) of the cylindrical portion 115a toward the inside in the radial direction (direction of arrow d) so as not to come into contact with a first rigid member 117a described later. In the axial direction, the inner peripheral portion 115b of the holder 115 is disposed on the other side (direction of arrow b) of the first bearing 113a so that a gap is formed between the inner peripheral portion 115b and the first bearing 113a.

[0025] The outer peripheral portion 115c of the holder 115 is an annular portion extending from one axial end (arrow a direction) of the cylindrical portion 115a to the outside in the radial direction (arrow c direction) by a dimension equal to or substantially equal to the thickness of the first end 114a of the cover 114. The holder 115 is positioned relative to the cover 114 by the surface on the other side of the outer peripheral portion 115c of the holder 115 coming into contact with the first end 114a of the cover 114 in the axial direction.

[0026] The holder 115 holds an elastic member 116. In this embodiment, the elastic member 116 is a substantially cylindrical and spiral coil spring with the axis X as its central axis. However, the elastic member 116 may be a member having various shapes formed from a material having rubber elasticity, for example. Examples of materials having rubber elasticity include thermosetting elastomers such as natural rubber and synthetic rubber, and thermoplastic elastomers such as styrene-based, olefin-based, PVC-based, acrylic-based, polyamide-based, polyester-based, and polyurethane-based. In addition, a plurality of elastic members 116 may be arranged side by side in the circumferential direction.

[0027] In the radial direction, the elastic member 116 is disposed inside the holder 115 (in the direction of the arrow d). Specifically, the elastic member 116 is disposed inside the cylindrical portion 115a of the holder 115 in the radial direction (in the direction of the arrow d), and is disposed on one side of the inner peripheral portion 115b of the holder 115 in the axial direction (in the direction of the arrow a). In the axial direction, the elastic member 116 is disposed between the inner peripheral portion 115b of the holder 115 and the outer ring 113ao of the first bearing 113a. In the radial direction, the elastic member 116 surrounds the shaft S and a first rigid member 117a (described later) from the outside (in the direction of the arrow c).

[0028] In the axial direction, the elastic member 116 is connected to the inner circumferential portion 115b of the holder 115 and the outer ring 113ao of the first bearing 113a. In this specification, a certain member and another member are "connected" to each other as long as the certain member is in contact with the other member, and the certain member does not necessarily have to be fixed immovably to the other member. The elastic member 116 biases the inner circumferential portion 115b of the holder 115 and the outer ring 113ao of the first bearing 113a. Specifically, in the axial direction, the elastic member 116 presses the inner circumferential portion 115b of the holder 115 and the outer ring 113ao of the first bearing 113a in a direction that moves them away from each other. That is, the elastic member 116 presses the inner circumferential portion 115b of the holder 115 toward the other side in the axial direction (the direction of the arrow b). Moreover, the elastic member 116 presses the outer ring 113ao of the first bearing 113a toward one side in the axial direction (the direction of the arrow a). As described above, the outer ring 113ao of the first bearing 113a and the holder 115 are fixed, so that the elastic member 116 is held in a state in which elastic energy in the axial direction is stored.

[0029] As described above, the second end 114b of the cylindrical cover 114 is fixed to the outside (arrow c direction) of the outer ring 113bo of the second bearing 113b in the radial direction via the annular spacer 119, and the holder 115 is fixed to the outside (arrow c direction) of the outer ring 113ao of the first bearing 113a in the radial direction. Therefore, a preload is applied by the elastic member 116 to the outer ring 113ao of the first bearing 113a and the outer ring 113bo of the second bearing 113b so as to move away from each other in the axial direction.

[0030] In this embodiment, the magnet 112 is a cylindrical permanent magnet having four magnetic poles, with different magnetic poles (S poles and N poles) alternately magnetized in the circumferential direction. However, the number of magnetic poles of the magnet 112 is not limited to four, and may be any number according to the design of the motor 100. In the radial direction, the inner diameter of the magnet 112 is the same as the outer diameter of the shaft S or is slightly larger than the outer diameter of the shaft S. The magnet 112 is fixed to the outer surface of the shaft S in the radial direction (direction of the arrow c) by adhesion or press fitting. In the axial direction, the magnet 112 is disposed between the first bearing 113a and the second bearing 113b, and is spaced a predetermined distance from the first bearing 113a and the second bearing 113b. The size (outer diameter) Q1 of the magnet 112 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.

[0031] A cylindrical protective member 118 is provided so as to cover the radially outer (arrow c direction) surface (outer circumferential surface) of the magnet 112. The protective member 118 is provided, for example, to prevent the magnet 112 from being broken or scattered. However, the motor 100 does not necessarily have to include the protective member 118. In the radial direction, the outer (arrow c direction) surface of the protective member 118 and the inner (arrow d direction) surface of the cover 114 face each other at a distance.

[0032] In the axial direction, a member (first rigid member) 117a is disposed between the magnet 112 and the first bearing 113a. The first rigid member 117a supports the first bearing 113a with respect to the magnet 112. In addition, in the axial direction, a member (second rigid member) 117b is disposed between the magnet 112 and the second bearing 113b. The second rigid member 117b supports the second bearing 113b with respect to the magnet 112. In this specification, the term "rigid member" refers to a member having rigidity with respect to the elastic member 116 (i.e., being less susceptible to elastic deformation compared to the elastic member 116). The first rigid member 117a and the second rigid member 117b have the same shape and dimensions, and are disposed symmetrically with respect to a plane perpendicular to the axis X, sandwiching the magnet 112. However, the first rigid member 117a and the second rigid member 117b may have different shapes and dimensions.

[0033] The first rigid member 117a and the second rigid member 117b each have annular portions 117a1 and 117b1 and protruding portions 117a2 and 117b2. In the radial direction, the inner diameters of the annular portions 117a1 and 117b1 are the same as or slightly larger than the outer diameter of the shaft S. The annular portions 117a1 and 117b1 are fixed to the radially outer surface (arrow c direction) of the shaft S by adhesion or press fitting. In the radial direction, the outer diameters of the annular portions 117a1 and 117b1 are smaller than the outer diameter of the magnet 112. In addition, in the radial direction, the outer diameters of the annular portions 117a1 and 117b1 are smaller than the inner diameter of the inner periphery 115b of the holder 115. In the radial direction, the annular portion 117a1 of the first rigid member 117a faces the inner circumferential portion 115b of the holder 115 at a predetermined distance.

[0034] The protrusions 117a2 and 117b2 are annular portions that protrude in the axial direction from the faces of the annular portions 117a1 and 117b1 that are away from the magnet 112 and that come into contact with the inner ring 113ai of the first bearing 113a and the inner ring 113bi of the second bearing 113b, respectively. The protrusions 117a2 and 117b2 protrude from the radially inner regions (in the direction of the arrow d) of the annular portions 117a1 and 117b1, respectively.

[0035] The first rigid member 117a is connected to the magnet 112 and the inner ring 113ai of the first bearing 113a. The second rigid member 117b is connected to the magnet 112 and the inner ring 113bi of the second bearing 113b. The first rigid member 117a and the second rigid member 117b are made of a metal such as copper. The first rigid member 117a and the second rigid member 117b may be made of other materials, but when used as a balancer for adjusting the rotation balance of the shaft S, it is preferable that they are made of a metal with a large specific gravity.

[0036] The motor 100 is an inner rotor type brushless DC motor. When the motor 100 operates, 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 rigid member 117a, the second rigid member 117b, and the protective member 118 rotate together.

[0037] The motor 100 according to this embodiment can be manufactured by assembling the stationary side components, i.e., the coil 120, the magnetic body 130, the case 140, and the lid 150, and then inserting the separately assembled bearing device 110. This makes it possible to improve the coaxiality of both the rotating side and the stationary side, and the coaxiality of the first bearing 113a and the second bearing 113b.

[0038] In assembling the bearing device 110, for example, the holder 115 is inserted into the cover 114 and fixed by adhesion or the like, and then the first bearing 113a is press-fitted into the holder 115 with the elastic member 116 interposed therebetween, and the outer ring 113ao of the first bearing 113a and the holder 115 are fixed by adhesion or the like. At this time, the outer ring 113ao of the first bearing 113a and the holder 115 are fixed in a state in which the outer ring 113ao of the first bearing 113a and the outer ring 113bo of the second bearing 113b are preloaded by the elastic member 116 so as to move away from each other in the axial direction. As a result, the motor 100 has a high resonance frequency and is suitable for high-speed rotation applications. In addition, since the holder 115 is fixed to the cover 114 at the outer circumferential surface of the cylindrical portion 115a, wobbling is unlikely to occur when the cover 114 and the holder 115 are fixed, and the coaxiality of the motor 100 is likely to be high. Therefore, the motor 100 according to this embodiment is less susceptible to vibrations during rotation and has a long life.

[0039] Furthermore, since motor 100 according to this embodiment does not need to be equipped with a large spring whose one end contacts outer ring 113ao of first bearing 113a and whose other end contacts outer ring 113bo of second bearing 113b, there is more space inside cover 114, the outer diameter of magnet 112 can be designed to be larger, and the torque can be increased.

[0040] [Second embodiment] Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 3 is a cross-sectional view of only the bearing device 210 in the motor according to this embodiment. The motor according to this embodiment has the same configuration as the motor 100 according to the first embodiment, except that it has the bearing device 210 instead of the bearing device 110. The bearing device 210 has the same configuration as the bearing device 110 of the motor 100 according to the first embodiment, except that it has a yoke 211 and a magnet 212 instead of the magnet 112. Hereinafter, members and parts having the same functions and configurations as those in the first embodiment are given the same reference numerals as those in the first embodiment, and detailed description thereof will be omitted.

[0041] In this embodiment, the magnet 212 is a cylindrical permanent magnet having four magnetic poles, with different magnetic poles (S poles and N poles) alternately magnetized in the circumferential direction. However, the number of magnetic poles of the magnet 212 is not limited to four, and may be any number depending on the design of the motor. In the radial direction, the inner diameter of the magnet 212 is larger than the outer diameter of the shaft S. The outer diameter of the magnet 212 is, for example, the same as 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 via a cylindrical yoke 211.

[0042] In the axial direction, the length of yoke 211 is the same as or approximately the same as the length of magnet 212. In the radial direction, the inner diameter of yoke 211 is the same as the outer diameter of shaft S or slightly larger than the outer diameter of shaft S. In the radial direction, the outer diameter of yoke 211 is the same as the inner diameter of magnet 212 or slightly smaller than the inner diameter of magnet 212. The radially outer surface (arrow c direction) of shaft S and the radially inner surface (arrow d direction) of yoke 211, and the radially outer surface (arrow c direction) of yoke 211 and the radially inner surface (arrow d direction) of magnet 212 are fixed by press-fitting or adhesive.

[0043] In the axial direction, the yoke 211 and the magnet 212 are disposed between the first bearing 113a and the second bearing 113b and at a predetermined distance from the first bearing 113a and the second bearing 113b. The size (outer diameter) Q2 in the radial direction of the magnet 212 is larger than the size (outer diameter) P in the radial direction of the first bearing 113a and the second bearing 113b.

[0044] The motor according to this embodiment has high coaxiality, a long life, and large torque due to the same principles as those described above for the motor 100 according to the first embodiment. Also, by fixing the magnet 212 to the shaft S via the yoke 211, it is possible to prevent the magnet 212 from cracking, and it is also easy to magnetize the magnet 212.

[0045] Although the motor of the present invention has been described above by way of preferred embodiments, the motor of the present invention is not limited to the configuration of the above embodiments. For example, in the above embodiments, the case 140 is cylindrical, but in the motor of the present invention, the case may be of any shape. Also, in the above embodiments, the bearing device 110, 210 has the first rigid member 117a and the second rigid member 117b, but in the motor of the present invention, the bearing device may have only one of the rigid members, or may not have any rigid member at all. Also, the first rigid member 117a and the second rigid member 117b do not have to have the same shape and dimensions.

[0046] In the above embodiment, cover 114 and spacer 119 are separate members independent of each other, but the cover and spacer may be formed as an integrated member. Similarly, in the above embodiment, cover 114 and holder 115 are separate members independent of each other, but the cover and holder may be formed as an integrated member.

[0047] In the above embodiment, the outer diameters Q1, Q2 of the magnets 112, 212 are larger than the outer diameter P of the first bearing 113a and the second bearing 113b, but in the motor of the present invention, the outer diameter of the magnet may be equal to the outer diameter of the bearing or may be smaller than the outer diameter of the bearing. Also, in the above embodiment, the second bearing 113b has the same dimensions and configuration as the first bearing 113a, but in the motor of the present invention, the first bearing and the second bearing may have different dimensions and configurations.

[0048] In addition, those skilled in the art can appropriately modify the motor of the present invention and change the shapes, dimensions, and combinations of various components according to conventional knowledge. As long as the configuration of the present invention is still provided even after such modifications, it is of course included in the scope of the present invention. [Explanation of symbols]

[0049] 100...motor, 112, 212...magnet, 113a...first bearing, 113b...second bearing, 114...cover, 115...holder, 116...elastic member, 117a, 117b...rigid member, 118...protective member, 119...spacer, 120...coil, S...shaft.

Claims

1. A shaft and A magnet and A coil and a first bearing disposed on one end side of the shaft in the axial direction; a second bearing disposed on the other end side of the shaft in the axial direction; a holder fixed to the first bearing; a cover fixed to the first bearing via the holder in a radial direction; an elastic member disposed radially inside the holder, The elastic member is axially connected to the holder and the first bearing.

2. the first bearing includes an outer ring; the holder has an inner periphery; The motor according to claim 1 , wherein the elastic member is connected to the outer ring of the first bearing and an inner periphery of the holder.

3. The motor according to claim 1 or 2, wherein the magnet is disposed radially inside the cover.

4. a member having rigidity relative to the elastic member, The motor according to claim 1 , wherein the rigid member supports the first bearing relative to the magnet.

5. the first bearing includes an inner ring; the shaft is fixed to the inner ring of the first bearing, 5. The motor according to claim 4, wherein the rigid member is connected to the magnet and the inner ring of the first bearing.

6. 5. The motor according to claim 4, wherein the rigid member is a balancer that adjusts the rotational balance of the shaft.

7. The motor according to claim 1 or 2, wherein the cover is a stationary member.

8. a stator including the coil; The motor according to claim 1 or 2, wherein the cover is fixed to the stator.

9. 3. The motor according to claim 1, wherein a radial size of the magnet is larger than a radial size of the first bearing or the second bearing.

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