Motor and fan motor

Abstract

The invention provides a motor and a fan motor. In a motor, a rotor is supported by a bearing so as to be rotatable about a central axis extending in an axial direction. The rotor has a rotor cover portion and a first protrusion portion. The rotor cover portion expands in a radial direction. The first protruding portion protrudes in one axial direction from the rotor cover portion, extends along the central axis, and is rotatably supported by a bearing. The bearing has a cylindrical shape extending in the axial direction and surrounds the first protruding portion. A hole extending in the other axial direction is disposed at one axial end of the first protrusion. The axial length of the hole part is smaller than half of the axial length of the first protruding part.

Description

Technical Field

[0001] The invention relates to a motor and a fan motor. Background Art

[0002] In the past, fan motors in which moving blades can rotate circumferentially together with a rotor are known. For example, a fan motor has a bearing device, a plurality of fans such as moving blades, and a drive unit for rotating the fans together with a rotating member. The bearing device has a rotating member such as a rotor and a bearing. A plurality of fans are provided on the rotating member. The rotating member has a hub portion and a shaft portion. The shaft portion is formed integrally with the hub portion and is inserted into the inner circumference of the bearing. The drive unit has a coil on a fixed side and a magnet fixed to the hub portion on the rotating side. By rotating the magnet using the excitation force between the magnet and the coil, the rotating member rotates relative to the bearing (see Japanese Patent Gazette No. 2015-064019).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2015-064019 Summary of the invention

[0006] Problems to be solved by the invention

[0007] However, in Japanese Patent Publication No. 2015-064019, the shaft of the rotating component is a cylindrical shape extending in the axial direction. Therefore, for example, after the fan motor is assembled, if an external force is applied to adjust the posture of the rotating component in order to adjust the rotation balance, the shaft may be deformed due to insufficient strength and rigidity of the shaft. That is, after assembly, it is sometimes difficult to adjust the posture of the rotating component.

[0008] An object of the present invention is to provide a technology that can safely adjust the posture of a rotor even after assembly.

[0009] Solutions to Solve Problems

[0010] In an exemplary motor of the present invention, a rotor is supported by a bearing so as to be rotatable about a central axis extending in an axial direction. The rotor has a rotor cover and a first protrusion. The rotor cover extends radially. The first protrusion protrudes from the rotor cover in one axial direction and extends along the central axis, and is supported by the bearing so as to be rotatable. The bearing is cylindrical and extends in the axial direction, and surrounds the first protrusion. A hole portion extending in the other axial direction is arranged at one axial end of the first protrusion. The axial length of the hole portion is less than half of the axial length of the first protrusion.

[0011] An exemplary fan motor of the present invention includes the above-described motor.

[0012] Effects of the Invention

[0013] According to the motor and the fan motor of the example of the present invention, it is possible to provide a technology that can safely adjust the posture of the rotor even after assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a cross-sectional view showing a structural example of a fan motor.

[0015] Figure 2 It is a perspective view showing the appearance of a fan motor.

[0016] In the figure:

[0017] 100—fan motor; 101—motor; 102—impeller; 1021—impeller cover; 1022—impeller cap; 1023—impeller barrel; 1024—moving blade; 103—cylindrical frame; 104—rib; 1—rotor; 11—rotor cover; 12—rotor barrel; 13—magnet; 14—first protrusion; 141—hole; 15—wall; 16—second protrusion; 2—stator; 21—stator core; 22—insulator; 23—coil; 3—housing; 31—bearing holder; 311—holder barrel; 3 12—the peripheral wall of the retaining frame; 313—the inner flange; 32—the bearing; 321—the protruding wall; 33—the base; 331—the plate; 332—the inner peripheral wall; 333—the outer peripheral wall; 4—the circuit board; 5—the stopper; 51—the column; 52—the flange; 6—the dynamic pressure groove; 61—the first dynamic pressure groove; 62—the second dynamic pressure groove; 63—the third dynamic pressure groove; F—the fluid; CA—the central axis; Da—one axial side; Db—the other axial side; L1, L2—the axial length; W1, W2—the axial width; φ1, φ2, φ3—the outer diameter DETAILED DESCRIPTION

[0018] Exemplary embodiments will be described below with reference to the accompanying drawings.

[0019] In addition, in the present specification, in the fan motor 100 and the motor 101, the direction parallel to the center axis CA is referred to as the "axial direction". The axial direction from the rotor cover portion 11 described later toward the base portion 33 is referred to as the "one axial direction Da", and the direction from the base portion 33 toward the rotor cover portion 11 is referred to as the "other axial direction Db". In addition, the direction orthogonal to the center axis CA is referred to as the "radial direction". In the radial direction, the direction close to the center axis CA is referred to as the "radial inner side", and the direction away from the center axis CA is referred to as the "radial outer side". In addition, the rotation direction centered on the center axis CA is referred to as the "circumferential direction".

[0020] In addition, in this specification, "annular" includes not only a shape that is continuously connected without gaps in the entire area in the circumferential direction centered on the central axis CA, but also a shape that has one or more gaps in a part of the entire area centered on the central axis CA. In addition, it also includes a shape that draws a closed curve on a curved surface intersecting the central axis CA with the central axis CA as the center.

[0021] In addition, in the positional relationship between any one of the orientations, lines and planes and any other one, "parallel" includes not only a state where the two do not intersect at all no matter where they extend, but also a state where they are substantially parallel. In addition, "perpendicular" and "orthogonal" include not only a state where the two intersect at 90 degrees, but also a state where they are substantially perpendicular and a state where they are substantially orthogonal. That is, "parallel", "perpendicular" and "orthogonal" include a state where there is an angular deviation in the positional relationship between the two to a degree that does not deviate from the main purpose of the present invention.

[0022] In addition, these names are used only for explanation, and are not intended to limit actual positional relationships, directions, names, etc.

[0023] <1. Implementation Method>

[0024] Figure 1 2 is a cross-sectional view showing a structural example of the fan motor 100 . Figure 2 1 is a perspective view showing the appearance of the fan motor 100. Figure 1 Shown with including Figure 2 The cross-sectional structure when the fan motor 100 is hypothetically cut by the double-dashed line II and the plane of the central axis CA.

[0025] <1-1. Fan motor 100>

[0026] The fan motor 100 of this embodiment is an axial flow fan that sends airflow in the axial direction. However, this example does not exclude that the fan motor 100 is a structure other than an axial flow fan. For example, the fan motor 100 can be a blower fan or a centrifugal fan.

[0027] like Figure 1 and Figure 2 As shown, the fan motor 100 includes a motor 101 and an impeller 102. The impeller 102 can rotate with a rotor 1 described later of the motor 101 about a central axis CA, and is fixed to at least a rotor cover 11 of the rotor 1. The motor 101 drives the impeller 102 to rotate. In the fan motor 100 of this embodiment, as described later, the posture of the rotor 1 (and the impeller 102) can be safely adjusted even after assembly.

[0028] The impeller 102 includes an impeller cover 1021, an impeller cap 1022, an impeller tube 1023, and a plurality of moving blades 1024. The impeller cover 1021 is an annular shape surrounding the second protrusion 16 described later of the rotor 1, and is arranged on the other axial end surface of the rotor cover 11. As described above, the impeller 102 includes the impeller cover 1021. The impeller cap 1022 is arranged at the radial inner end of the impeller cover 1021, and covers the opening (the reference numeral is omitted) of the impeller cover 1021 and one axial end of the second protrusion 16 of the rotor 1. In addition, the opening is arranged radially inside the radial inner end of the impeller cover 1021. In addition, the impeller cap 1022 may be omitted. The impeller tube 1023 is cylindrical, and extends from the radial outer end of the impeller cover 1021 to one axial direction Da. In addition, the impeller cover 1021 and the impeller cylinder 1023 constitute an impeller base (with reference numerals omitted) with a cover and a cylindrical shape, which extends in the axial direction and is mounted on the rotor 1. A plurality of moving blades 1024 are arranged on the radially outer side of the impeller cylinder 1023 and are arranged in the circumferential direction. The impeller 102 is rotated by the motor 101, and the moving blades 1024 rotate in the circumferential direction. Therefore, the airflow flows in the axial direction.

[0029] Preferably, the material of the impeller 102 is polycarbonate resin. Polycarbonate resin is a material with high toughness and mechanical strength. Therefore, by adopting polycarbonate resin, the rigidity of the impeller 102 can be improved. However, this example does not exclude a structure in which the material of the impeller 102 is not polycarbonate resin. For example, the material of the impeller 102 may be a resin material other than polycarbonate resin, or may be a metal material such as Al or Al alloy.

[0030] In addition, the present invention is not limited to the above-mentioned example, and the moving blades 1024 may be integrated with the rotor 1, or a plurality of moving blades may be arranged side by side on the radially outer side of the rotor 1. In this case, the impeller cover 1021, the impeller cap 1022, and the impeller cylinder 1023 are omitted.

[0031] In addition, the fan motor 100 also includes a cylindrical frame 103 and ribs 104. The cylindrical frame 103 extends axially and surrounds the motor 101 and the impeller 102. The cylindrical frame 103 is spaced apart from the motor 101 and the impeller in the radial direction, and a wind tunnel (with reference numerals omitted) for airflow is formed in the space between them. The ribs 104 extend at least radially, and a plurality of them are arranged circumferentially on one side Da of the axial direction of the wind tunnel. The ribs 104 function as stationary blades for rectifying the airflow flowing in the wind tunnel. In addition, the ribs 104 connect the base portion 33 of the motor 101 and one axial end of the cylindrical frame 103. That is, the radial inner end of the rib 104 is connected to the base portion 33. The radial outer end of the rib 104 is connected to the radial inner side surface of the cylindrical frame 103.

[0032] <1-2. Motor 101>

[0033] Next, refer to Figure 1 and Figure 2 The following describes a configuration example of the motor 101. The motor 101 includes a rotor 1, a stator 2, a housing 3, a circuit board 4, a stopper 5, a first dynamic pressure groove 61, a second dynamic pressure groove 62, and a third dynamic pressure groove 63. In addition, hereinafter, the first dynamic pressure groove 61, the second dynamic pressure groove 62, and the third dynamic pressure groove 63 are sometimes collectively referred to as "dynamic pressure grooves 6".

[0034] <1-2-1. Rotor 1>

[0035] In the motor 101 of the present embodiment, the rotor 1 is supported by the bearing 32 so as to be rotatable about the central axis CA extending in the axial direction. In the present embodiment, the rotor 1 is made of metal such as stainless steel, Al, or Al alloy.

[0036] The rotor 1 includes a rotor cover portion 11 , a rotor tube portion 12 , a magnet 13 , a first protrusion 14 , a wall portion 15 , and a second protrusion 16 .

[0037] The rotor cover 11 extends in the radial direction. As described above, the rotor 1 includes the rotor cover 11. The rotor cover 11 is arranged closer to the other axial direction Db than the stator 2.

[0038] The rotor tube portion 12 extends from the radially outer end portion of the rotor cover portion 11 in the axial direction Da. As described above, the rotor 1 includes the rotor tube portion 12. The rotor tube portion 12 is cylindrical and surrounds the stator 2.

[0039] The impeller 102 (more specifically, the impeller base) is fixed to the rotor cover 11 and the rotor barrel 12. In this way, the impeller 102 can be fixed to the rotor 1 by post-installation. Therefore, it is easy to perform corrections such as shake correction after fixation. Moreover, even if the correction is performed or an external force is applied to the impeller 102, it is difficult to affect the support structure of the rotor 1. Therefore, the possibility of damage to the bearing 32 supporting the rotor 1 can be reduced or prevented. Therefore, even after the fan motor 100 is assembled, the posture of the impeller 102 can be safely adjusted.

[0040] In the present embodiment, the rotor cylinder 12 is pressed into the inner side of the impeller cylinder 1023, thereby being fixed to the inner peripheral surface (radial inner side) of the impeller cylinder 1023. When pressed in, the rotor cover 11 does not collide with the impeller 102 in the axial direction. That is, in the axial direction, the upper surface of the rotor cover 11 and the impeller 102 (for example, the lower surface of the impeller cover 1021) are opposed to each other with a gap in the shape of an annulus surrounding the central axis CA. In other words, the upper surface of the rotor cover 11 and the lower surface of the impeller cover 1021 do not contact in the axial direction over the entire circumference.

[0041] Thus, when the impeller 102 is mounted on the rotor 1 by press-fitting, for example, by using a press-fitting jig with high parallelism accuracy, vibration of the impeller 102 during rotation can be prevented. Specifically, when the rotor cylinder 12 is press-fitted into the inner circumferential surface of the impeller cylinder 1023, a press-fitting jig with high parallelism accuracy is arranged between the upper surface of the rotor cover 11 and the lower surface of the impeller cover 1021 in the axial direction. Thus, a gap can be left between the rotor cover 11 and the impeller cover 1021 while the two are parallel with high accuracy, and collision between the two during press-fitting can be prevented. In other words, the rotor cover 11 can be prevented from abutting against the impeller cover 1021 in the axial direction. Therefore, even if one of the upper surface of the rotor cover 11 and the lower surface of the impeller cover 1021 is tilted from a plane perpendicular to the rotation axis (central axis CA) of the rotor 1, the other can be prevented from tilting from the plane due to collision. That is, if there is no collision, the rotor cylinder 12 is pressed into the inner circumference of the impeller cylinder 1023 in the same manner as the press-fitting jig, so that the two can be parallel with high precision. Therefore, it is possible to suppress or prevent the center axis of the impeller 102 from deviating from the rotation axis of the rotor 1 (i.e., the center axis CA) due to the abutment between the two. In addition, even if the rotation vibration of the impeller 102 occurs after installation, since a gap is arranged between the upper surface of the rotor cover 11 and the lower surface of the impeller cover 1021, the part of the impeller 102 with large vibration can be pressurized to one axial side (i.e., the rotor 1 side) to adjust the position. That is, even after installation, the relative position relationship of the center axis of the impeller 102 with respect to the rotation axis of the rotor 1 (i.e., the center axis CA) can be easily adjusted, and the vibration of the impeller 102 can be effectively suppressed or prevented.

[0042] The magnet 13 is arranged on the radial inner side of the rotor barrel 12, and is radially opposite to the stator 2 (especially the stator core 21 described later). For example, the magnet 13 is arranged radially outwardly than the stator 2 (especially the stator core 21), and surrounds the stator 2 (especially the stator core 21). On the radial inner side of the magnet 13, a plurality of different magnetic poles (S pole, N pole) are arranged alternately in the circumferential direction. In addition, the magnet 13 can be directly arranged on the radial inner side of the rotor barrel 12, or can be arranged to sandwich a magnetic body (not shown). For example, in the latter, a magnetic body (a cylindrical body, or a plurality of magnetic body sheets arranged in the circumferential direction) can also be arranged on the radial inner side of the rotor barrel 12, and the magnet 13 can be arranged on the radial inner side of the magnetic body.

[0043] The first protrusion 14 is the shaft (rotation axis) of the rotor 1. The first protrusion 14 protrudes from the rotor cover 11 in one axial direction Da and extends along the central axis CA. As described above, the rotor 1 has the first protrusion 14. The first protrusion 14 is supported by the bearing 32 so as to be rotatable. In addition, a hole portion 141 extending in the other axial direction Db is arranged at one axial end portion of the first protrusion 14. The hole portion 141 is a recessed portion recessed in the other axial direction Db and extends along the central axis CA.

[0044] The axial length L1 of the hole 141 is smaller than half of the axial length L2 of the first protrusion 14. Thus, the axial length L1 of the cylindrical portion of the first protrusion 14 supported by the bearing 32 so as to be rotatable, which has the hole 141 on one axial side Da, is smaller than the axial length L2 of the solid portion on the other axial side Db of the cylindrical portion. That is, more than half of the first protrusion 14 is a solid columnar body. Therefore, the strength and rigidity of the first protrusion 14 can be improved. In addition, the solid portion is also connected to the rotor cover 11. Therefore, after the fan motor 100 is assembled (especially after the first protrusion 14 is supported by the bearing 32), even if the posture of the rotor 1 (and the impeller 102) is adjusted for the purpose of adjusting the rotation balance, it is difficult for the first protrusion 14 and the bearing 32 to be deformed by external force. Therefore, the strength and rigidity of the support structure of the bearing 32 for the first protrusion 14 can be improved. Therefore, even after the fan motor 100 and the motor 101 are assembled, the posture of the rotor 1 (and the impeller 102 ) can be safely adjusted.

[0045] The wall portion 15 protrudes from the rotor cover portion 11 in the axial direction Da and surrounds the other axial end portion of the bearing 32. As described above, the rotor 1 has a cylindrical wall portion 15. Moreover, the wall portion 15 surrounds the other axial end portion of the first protrusion 14. That is, the wall portion 15 is a cylindrical body arranged on an axial end surface of the rotor cover portion 11 and extending in the axial direction. The wall portion 15 is arranged radially outside the first protrusion 14 and the bearing 32, and is radially opposed to the other axial end portion of the bearing 32 with a gap. The cylindrical wall portion 15 forms a cylindrical first space (with reference numerals omitted) extending in the axial direction between the cylindrical wall portion 15 and the other axial end portion of the bearing 32. The first space functions as a first labyrinth seal, for example, it can suppress leakage of the fluid F described later between the first protrusion 14 and the bearing 32, and intrusion of water and dust from the outside into the space between the first protrusion 14 and the bearing 32.

[0046] In addition, without limiting to the example of this embodiment, the wall portion 15 may rotatably support the other axial end portion of the bearing 32. That is, the radial inner side surface of the wall portion 15 may directly contact and slide with the other axial end portion of the bearing 32, or may indirectly contact with the other axial end portion via the fluid F or the like. In this way, the rotor 1 can rotate in a more balanced manner.

[0047] The second protrusion 16 protrudes from the rotor cover 11 in the other axial direction Db and extends along the central axis CA. As described above, the rotor 1 has the second protrusion 16. That is, the second protrusion 16 is a columnar body extending in the axial direction and is arranged at the center of the other axial end surface of the rotor cover 11.

[0048] Preferably, if Figure 1 As shown, when viewed from the axial direction, the outer diameter φ2 of the second protrusion 16 is larger than the outer diameter φ1 of the first protrusion 14. In this way, the thickness of the rotor 1 near the connection portion between the first protrusion 14 and the rotor cover 11 can be increased (for example, the sum of the axial width of the rotor cover 11 and the axial width W2 of the second protrusion 16 described later). Therefore, the strength and rigidity of the connection portion between the two can be improved.

[0049] More preferably, if Figure 1 As shown, when viewed from the axial direction, the outer diameter φ2 of the second protrusion 16 is larger than the outer diameter φ3 of the bearing 32. Thus, when viewed from the axial direction, the thickness of the rotor 1 can be increased in a wide range centered on the connection portion between the first protrusion 14 and the rotor cover 11 (for example, the sum of the axial width W2 of the rotor cover 11 and the axial width W2 of the second protrusion 16). Therefore, the strength and rigidity of the connection portion between the two can be further improved.

[0050] However, the above-mentioned examples do not exclude the structure of φ1 ≥ φ2 and the structure of (φ1 ≤) φ2 ≤ φ3, and do not exclude the structure of the second protrusion 16 being a cylindrical structure extending in the axial direction.

[0051] In addition, it is preferred that the other axial end of the second protrusion 16 of the motor 101 is arranged at a position closer to the other axial direction Db than the radial inner end of the impeller cover 1021. In other words, the axial width W2 of the second protrusion 16 is larger than the axial width W1 of the radial inner end of the impeller cover 1021. In this way, since the axial width W2 of the second protrusion 16 can be further increased, the thickness of the rotor 1 near the connection portion between the first protrusion 14 and the rotor cover 11 can be further increased (for example, the sum of the axial width of the rotor cover 11 and the axial width W2 of the second protrusion 16). Therefore, the strength and rigidity of the connection portion between the two can be further improved. However, this example does not exclude a structure where W1≥W2.

[0052] In addition, in the present embodiment, the second protrusion 16 has a gap between it and the impeller 102 (for example, the radial inner end of the impeller cover 1021, the impeller cover 1022). However, this example is not limited to the present invention, and the second protrusion 16 may also be in contact with the impeller 102. For example, the radial outer end of the second protrusion 16 may also be in contact with the impeller 102. In addition, the second protrusion 16 (especially the other axial end) may also be in contact with the impeller 102 (especially the impeller cap 1022). In this way, the second protrusion 16 can be fitted into the opening of the impeller cover 1021, the recessed portion (the reference numerals are omitted) on the axial side Da of the impeller cap 1022, etc. Therefore, the impeller 102 can be fixed to the rotor 1 more firmly.

[0053] In addition, in the present embodiment, the rotor cover 11, the rotor tube 12, the first protrusion 14, the wall 15, and the second protrusion 16 are integrated and constitute a single component. However, this example does not exclude a structure in which at least a part of these components does not constitute a single component with other parts. For example, the first protrusion 14 may be integrated with at least the rotor cover 11 by insert molding, but not a single component.

[0054] <1-2-2. Stator 2>

[0055] The stator 2 generates magnetic flux through the power supply, which causes the rotor 1 to rotate. Figure 1 As shown, the stator 2 includes a stator core 21 , an insulator 22 , and a coil portion 23 .

[0056] The stator core 21 is an annular magnetic body surrounding the central axis CA. In the present embodiment, it is a laminated body formed by overlapping radially extending plate-shaped electromagnetic steel sheets in the axial direction. The stator core 21 is fixed to the radial outer side of the bearing holder 31. In addition, the stator core 21 has a slot (icon omitted). The slot passes through the stator core 21 in the axial direction, and a plurality of slots are arranged in the circumferential direction. The stator core 21 is provided with a plurality of coil portions 23 arranged in the circumferential direction.

[0057] The insulator 22 has electrical insulating properties and is disposed on the surface of the stator core 21 (particularly, both end surfaces in the axial direction and the inner side surfaces of the slots, etc.).

[0058] The coil portion 23 is a component in which a conductive wire (reference numerals omitted) is arranged in a coil shape on the stator core 21 via an insulator 22. The conductive wire is, for example, an enameled copper wire or a metal wire covered with an electrical insulating member, and is wound around teeth (reference numerals omitted) between slots adjacent in the circumferential direction in the stator core 21 to form the coil portion 23. When a drive current is supplied to each coil portion 23, the stator 2 is excited and the rotor 1 is driven.

[0059] <1-2-3. Housing 3>

[0060] The housing 3 includes a bearing holder 31 , a bearing 32 , and a base portion 33 .

[0061] The bearing holder 31 is cylindrical and extends in the axial direction, and surrounds and holds the bearing 32. The motor 101 further includes the bearing holder 31. The bearing holder 31 surrounds the central axis CA and the first protrusion 14, and holds the stator core 21 on its radially outer side.

[0062] In addition, the bearing retainer 31 also surrounds at least one axial side Da of the wall portion 15. In this way, a cylindrical second space (reference numerals omitted) extending in the axial direction can be formed between the wall portion 15 and the cylindrical bearing retainer 31 (for example, the retainer peripheral wall portion 312). The second space functions as a second labyrinth seal, for example, and can further suppress leakage of the fluid F between the first protrusion 14 and the bearing 32, and intrusion of water and dust from the outside into the space between the first protrusion 14 and the bearing 32.

[0063] For example, the bearing retainer 31 includes a retainer tube portion 311 and a retainer peripheral wall portion 312. The retainer tube portion 311 is a tube extending in the axial direction, and surrounds the central axis CA, the first protrusion 14, and the bearing 32. The retainer peripheral wall portion 312 is a tube extending from the other axial end portion of the retainer tube portion 311 to the other axial direction Db, and surrounds at least one axial direction Da side of the wall portion 15 of the rotor 1. That is, the retainer peripheral wall portion 312 is arranged radially outward from the wall portion 15, and is radially opposed to the wall portion 15 with a gap. In addition, the other axial end portion of the retainer peripheral wall portion 312 is axially opposed to one axial end surface of the rotor cover portion 11 with a gap.

[0064] Preferably, the retainer peripheral wall portion 312 is arranged at the radially outer end portion at the other axial end portion of the retainer tube portion 311. In this way, the axial end portion of the wall portion 15 can be axially opposed to the axially other end portion of the retainer tube portion 311 with a gap. Therefore, a circular annular third space (illustration mark omitted) can also be formed between the wall portion 15 and the axially other end portion of the retainer tube portion 311. The third space can function as a third labyrinth seal. However, this example does not exclude a structure in which the retainer peripheral wall portion 312 is arranged radially inward (particularly radially inner end portion) at the axially other end portion of the retainer tube portion 311.

[0065] In addition, the bearing retainer 31 also has an inner flange portion 313. The inner flange portion 313 extends radially inward from one axial end of the retainer tube portion 311 and extends circumferentially. For example, the inner flange portion 313 may also be in the shape of a ring surrounding the central axis CA. However, this example does not exclude a structure in which the inner flange portion 313 is not in the shape of a ring as described above.

[0066] The bearing 32 is arranged on the inner peripheral surface (i.e., the radial inner side) of the bearing holder 31. The bearing 32 is cylindrical and extends in the axial direction, and surrounds the first protrusion 14. In other words, the first protrusion 14 is inserted into the inside of the bearing holder 31 and the bearing 32. The bearing holder 31 supports the first protrusion 14 rotatably via the bearing 32. In addition, an axial end surface of the bearing 32 is axially opposed to the axial other end surface of the flange portion 52 of the stopper 5 described later, via the fluid F. The axial other end surface of the bearing 32 is axially opposed to an axial end surface of the rotor cover portion 11, via the fluid F. The radial inner side surface of the bearing 32 is radially opposed to the radial outer side surface of the first protrusion 14, via the fluid F.

[0067] In the present embodiment, the bearing 32 is a sleeve that functions as a fluid dynamic pressure bearing. The fluid F is disposed between the first protrusion 14 and the bearing 32. In addition, the fluid F is lubricating oil in the present embodiment. However, this example is not limited thereto, and the fluid F may be a liquid other than lubricating oil, or may be a gas such as air. A third dynamic pressure groove 63 described later is disposed on at least one of the radially outer side surface of the first protrusion 14 and the radially inner side surface of the bearing 32 for generating dynamic pressure on the fluid F between the two. When the shaft 10 rotates, dynamic pressure is generated in the fluid F between the two through the third dynamic pressure groove 63. The bearing 32 is separated from the first protrusion 14 by this dynamic pressure. Therefore, the rotating first protrusion 14 is rotatably supported in a state where it does not contact the bearing 32.

[0068] In addition, in the present embodiment, the bearing 32 has a protruding wall portion 321. The protruding wall portion 321 protrudes toward one axial direction Da at the radially outer end portion of one axial end portion of the bearing 32. The protruding wall portion 321 is cylindrical and surrounds the central axis CA and the stopper 5 (the flange portion 52 described later). The protruding wall portion 321 is opposed to the flange portion 52 in the radial direction, and is opposed to the inner flange portion 313 of the bearing holder 31 in the axial direction.

[0069] The base portion 33 is arranged at one axial side Da closer to the stator 2, and extends radially outward from one axial end of the bearing retainer 31. The base portion 33 has a plate portion 331, an inner peripheral wall portion 332, and an outer peripheral wall portion 333. The plate portion 331 extends radially outward from one axial end of the bearing retainer 31 (retainer cylinder portion 311) and extends circumferentially. In the present embodiment, the plate portion 331 is an annular shape surrounding one axial end of the bearing retainer 31. The inner peripheral wall portion 332 is arranged at one axial end of the bearing retainer 31, and extends circumferentially from the radial inner end of the plate portion 331 to the other axial direction Db. The outer peripheral wall portion 333 extends circumferentially from the radial outer end of the plate portion 331 to the other axial direction Db. The radial inner end of the rib 104 is connected to the radial outer side of the outer peripheral wall portion 333. In the present embodiment, the inner peripheral wall portion 332 and the outer peripheral wall portion 333 are cylindrical in shape and extend in the axial direction.

[0070] <1-2-4. Circuit board 4>

[0071] The circuit board 4 is arranged on the other axial end surface of the plate portion 331 of the base portion 33. The circuit board 4 is electrically connected to the lead wire (reference numeral omitted) led out from the coil portion 23. The drive circuit of the stator 2 and the like are mounted on the circuit board 4, and are electrically connected to external wiring (not shown). The external wiring is led out to the outside of the motor 101, and the circuit board 4 is electrically connected to an external device, a power source, and the like.

[0072] <1-2-5. Stopper 5>

[0073] The stopper 5 is mounted on one axial end of the first protrusion 14. As described above, the motor 101 includes the stopper 5. As described above, the stopper 5 is mounted on one axial end of the first protrusion 14 and is rotatable about the central axis CA together with the rotor 1 (particularly the first protrusion 14).

[0074] The stopper 5 has a column 51. The column 51 is a columnar body extending in the axial direction and is embedded in the hole 141 of the first protrusion 14. That is, the column 51 is housed in the hole 141. In the hole 141, a fourth space (illustration mark omitted) is arranged at a position closer to the other axial direction Db than the column 51. That is, the other axial end of the column 51 and the inner surface of the hole 141 facing the axial direction Da (that is, the other axial end surface) are axially opposed with a gap (that is, the fourth space). In this way, the column 51 can be inserted into the hole 141 more reliably and stably. Therefore, the stopper 5 can be installed at one axial end of the first protrusion 14 with higher precision.

[0075] The stopper 5 further includes a flange 52. The flange 52 is disposed on one axial side Da relative to the first protrusion 14 and extends radially. For example, the flange 52 is in a disk shape and extends radially outward from one axial end of the column 51.

[0076] The means for attaching the stopper 5 to the first protrusion 14 may be bonding using an adhesive, welding, brazing using silver solder or the like, screwing, press-fitting of the column 51 , or the like.

[0077] <1-2-6. Dynamic pressure groove 6>

[0078] The dynamic pressure generating grooves 6 are a plurality of wedge-shaped patterns arranged in the circumferential direction and are composed of a plurality of grooves. The dynamic pressure generating grooves 6 are arranged on at least one of a pair of opposing surfaces to generate dynamic pressure in the fluid F interposed between the opposing surfaces.

[0079] The first dynamic pressure groove 61 as the dynamic pressure groove 6 is arranged on any one of the axial end face (at least a part of) of the bearing 32 and the axial other end face (at least a part of) the flange portion 52. In the present embodiment, the first dynamic pressure groove 61 is arranged on the axial end face of the bearing 32. Therefore, the first dynamic pressure groove 61 can generate a dynamic pressure in the thrust direction (i.e., axial direction) between the axial end face of the bearing 32 and the axial other end face of the flange portion 52, which are axially opposite to each other through the fluid F. Through this dynamic pressure, the bearing 32 can function as a fluid dynamic pressure bearing relative to the flange portion 52 of the stopper 5. Here, the first dynamic pressure groove 61 is connected to the axial end portion of the third dynamic pressure groove 63 on the axial one side Da side in the present embodiment, but it is not limited to this example and may not be connected.

[0080] The second dynamic pressure groove 62 as the dynamic pressure groove 6 is arranged on any one of the other axial end surface (at least a part of) the bearing 32 and the other axial end surface of the rotor cover 11. In the present embodiment, the second dynamic pressure groove 62 is arranged on the other axial end surface of the bearing 32. Therefore, the second dynamic pressure groove 62 can generate a dynamic pressure in the thrust direction between the other axial end surface of the bearing 32 and the axial one end surface of the rotor cover 11, which are axially opposed to each other via the fluid F. Through this dynamic pressure, the bearing 32 can function as a fluid dynamic pressure bearing relative to the rotor cover 11. Here, the second dynamic pressure groove 62 is connected to the other axial end portion of the third dynamic pressure groove 63 on the other axial side Db in the present embodiment, but it is not limited to this example and may not be connected.

[0081] For example, the first dynamic pressure groove 61 and the second dynamic pressure groove 62 in the dynamic pressure groove 6 include a first groove and a second groove. The first groove extends radially inward as it moves toward one side in the circumferential direction. The second groove extends radially outward as it moves toward one side in the circumferential direction. For example, the second groove extends from one circumferential end of the first groove. Thus, the first groove and the second groove form a wedge shape. The first dynamic pressure groove 61 and the second dynamic pressure groove 62 are composed of a plurality of wedge-shaped grooves arranged in the circumferential direction. In addition, the shape (in other words, pattern) formed by the first groove and the second groove is not limited to this example, and various shapes can be formed as long as the first groove and the second groove are included. For example, the shape of at least one of the first dynamic pressure groove 61 and the second dynamic pressure groove 62 can be a herringbone shape or a zigzag shape.

[0082] In addition, in the present embodiment, the motor 101 includes both the first dynamic pressure groove 61 and the second dynamic pressure groove 62. However, this is not limited to this example, and one of the two may be omitted. That is, the motor 101 only needs to include at least one of the first dynamic pressure groove 61 and the second dynamic pressure groove 62. In this way, the axial shake of the rotor 1 (particularly the first protrusion 14) can be suppressed by at least one of the first dynamic pressure groove 61 and the second dynamic pressure groove 62.

[0083] As the dynamic pressure groove 6, the third dynamic pressure groove 63 is also arranged on any one of (at least a part of) the radial inner side surface of the bearing 32 and (at least a part of) the radial outer side surface of the first protrusion 14. In the present embodiment, the third dynamic pressure groove 63 is arranged on a part of the radial inner side surface of the bearing 32. Therefore, the third dynamic pressure groove 63 can generate a dynamic pressure in the diameter direction (i.e., radial direction) between the radial inner side surface of the bearing 32 and the radial outer side surface of the first protrusion 14, which are radially opposed to each other via the fluid F. Through this dynamic pressure, the bearing 32 can function as a fluid dynamic pressure bearing relative to the first protrusion 14. Therefore, the third dynamic pressure groove 63 can suppress the radial shaking of the rotor 1 (especially the first protrusion 14).

[0084] For example, the third dynamic pressure groove 63 in the dynamic pressure groove 6 includes a third groove and a fourth groove. The first groove extends along one axial direction Da as it moves toward one circumferential direction. The fourth groove extends toward the other axial direction Db as it moves toward one circumferential direction. For example, the fourth groove extends from one circumferential end of the third groove. Thus, the third groove and the fourth groove form a wedge shape. The third dynamic pressure groove 63 is composed of a plurality of wedge-shaped grooves arranged in the circumferential direction. In addition, the shape (in other words, pattern) formed by the third groove and the fourth groove is not limited to this example, and various shapes can be formed as long as the third groove and the fourth groove are included. For example, the shape of the third dynamic pressure groove 63 can be a herringbone shape or a zigzag shape.

[0085] In addition, in a structure in which the wall portion 15 of the rotor 1 holds the other axial end portion of the bearing 32 in a rotatable manner, the motor 101 may also have a fourth dynamic pressure groove (not shown) as the dynamic pressure groove 6. The fourth dynamic pressure groove is arranged on either the inner peripheral surface (i.e., the radial inner surface) of the wall portion 15 or the radial outer surface of the other axial end portion of the bearing 32. In addition, the fourth dynamic pressure groove may be connected to the radial outer end portion of the second dynamic pressure groove 62 or may not be connected. In addition, the fourth dynamic pressure groove, like the third dynamic pressure groove 63, can be composed of a plurality of wedge-shaped grooves arranged in the circumferential direction. Alternatively, the shape of the fourth dynamic pressure groove may be a herringbone shape or a zigzag shape.

[0086] In this way, the fourth dynamic pressure groove can generate a dynamic pressure in the diameter direction (i.e., radial direction) between the radial outer side surface of the bearing 32 and the inner peripheral surface of the wall portion 15, which are radially opposed to each other via the fluid F. Through this dynamic pressure, the bearing 32 can function as a fluid dynamic pressure bearing relative to the wall portion 15. However, in this example, even if the wall portion 15 holds the other axial end of the bearing 32 in a rotatable manner, it does not exclude the structure in which the motor 101 does not have the fourth dynamic pressure groove.

[0087] <2. Others>

[0088] The above describes the embodiments of the present invention. In addition, the scope of the present invention is not limited to the above embodiments. The present invention can be implemented by applying various changes to the above embodiments without departing from the gist of the invention. In addition, the matters described in the above embodiments can be appropriately combined in any manner without causing contradictions.

[0089] For example, in the present embodiment, the bearing 32 functions as a fluid dynamic pressure bearing. However, this example does not exclude a structure in which the bearing 32 does not function as a fluid dynamic pressure bearing. For example, the example of the present embodiment does not exclude a structure in which the bearing 32 is a sliding bearing and the dynamic pressure groove 6 (and the fluid F) is omitted.

[0090] <3. Conclusion>

[0091] The embodiments described so far will be summarized below.

[0092] For example, the motor disclosed in this specification may have the following structure (first structure), which is a motor in which a rotor is supported by a bearing so as to be rotatable around a central axis extending in the axial direction,

[0093] The rotor has:

[0094] a rotor cover portion extending in a radial direction; and

[0095] a first protrusion that protrudes from the rotor cover in one direction in the axial direction and extends along the central axis and is rotatably supported by the bearing;

[0096] The bearing is cylindrical and extends in the axial direction, and surrounds the first protrusion.

[0097] A hole portion extending in the other axial direction is arranged at one axial end portion of the first protrusion.

[0098] The axial length of the hole portion is smaller than half of the axial length of the first protrusion.

[0099] In addition, the motor of the first structure may be of the following structure (second structure), further comprising:

[0100] a stopper mounted on one axial end portion of the first protrusion; and

[0101] At least one of the first dynamic pressure generating groove and the second dynamic pressure generating groove,

[0102] The stopper has a flange portion, which is arranged on the axial side of the first protrusion and extends in the radial direction.

[0103] The dynamic pressure groove comprises:

[0104] a first groove extending radially inward as it moves toward one side in the circumferential direction; and

[0105] The second groove extends radially outward as it moves toward one side in the circumferential direction.

[0106] An axial end surface of the bearing is axially opposed to an axial end surface of the flange portion via a fluid.

[0107] The first dynamic pressure generating groove is arranged on one of the axial end surface of the bearing and the other axial end surface of the flange portion.

[0108] The other axial end surface of the bearing is axially opposed to the one axial end surface of the rotor cover via the fluid.

[0109] The second dynamic pressure generating groove is disposed on one of the other axial end surface of the bearing and the one axial end surface of the rotor cover.

[0110] In addition, the motor of the first or second structure may be of the following structure (third structure):

[0111] The rotor further includes a cylindrical wall portion that protrudes from the rotor cover portion in one axial direction and surrounds the other axial end portion of the bearing.

[0112] In addition, the motor of the third structure may be of the following structure (fourth structure):

[0113] The invention also comprises a cylindrical bearing retainer, which extends in the axial direction and surrounds and retains the bearing.

[0114] The bearing cage further surrounds at least one axial side of the wall portion.

[0115] In addition, the motor of any one of the first to fourth structures may have the following structure (fifth structure):

[0116] The rotor further includes a second protrusion that protrudes from the rotor cover toward the other axial direction and extends along the central axis.

[0117] When viewed in the axial direction, the outer diameter of the second protrusion is larger than the outer diameter of the first protrusion.

[0118] In addition, the motor of the fifth structure may be of the following structure (sixth structure):

[0119] When viewed in the axial direction, the outer diameter of the second protrusion is larger than the outer diameter of the bearing.

[0120] In addition, the fan motor disclosed in this specification may have the following structure (seventh structure):

[0121] A motor having any one of the first to sixth structures.

[0122] In addition, the fan motor of the seventh structure may be of the following structure (eighth structure):

[0123] The device further comprises an impeller which is rotatable together with the rotor of the motor about the central axis.

[0124] The rotor further includes a rotor cylinder portion extending in one axial direction from a radially outer end portion of the rotor cover portion.

[0125] The impeller is fixed to the rotor cover and the rotor tube.

[0126] Alternatively, the fan motor disclosed in this specification may have the following structure (ninth structure), comprising:

[0127] The motor of the fifth or sixth structure; and

[0128] an impeller rotatable together with the rotor of the motor about the central axis and fixed to at least the rotor cover of the rotor,

[0129] The impeller has an impeller cover portion, which is in an annular shape surrounding the second protrusion and is arranged on the other axial end surface of the rotor cover portion.

[0130] The other axial end portion of the second protrusion of the motor is arranged on the other axial side relative to the radially inner end portion of the impeller cover portion.

[0131] In addition, the fan motor of the eighth or ninth structure may be of the following structure (tenth structure):

[0132] In the axial direction, the upper surface of the rotor cover portion faces the impeller via a circular gap surrounding the central axis.

[0133] In addition, the fan motor of any one of the eighth to tenth structures may be of the following structure (eleventh structure):

[0134] The material of the impeller may be polycarbonate resin.

[0135] Industrial Applicability

[0136] The present invention is useful for a motor in which a shaft is rotatably supported by a cylindrical bearing and a device including the motor.

Claims

1. A motor having a rotor supported by a bearing so as to be rotatable about a central axis extending in an axial direction, The motor is characterized in that The rotor has: a rotor cover portion extending in a radial direction; and a first protrusion that protrudes from the rotor cover in one direction in the axial direction and extends along the central axis and is rotatably supported by the bearing; The bearing is cylindrical and extends in the axial direction, and surrounds the first protrusion. A hole portion extending in the other axial direction is arranged at one axial end portion of the first protrusion. The axial length of the hole portion is smaller than half of the axial length of the first protrusion.

2. The motor according to claim 1, characterized in that Also available: a stopper mounted on an axial end portion of the first protrusion; and At least one of the first dynamic pressure generating groove and the second dynamic pressure generating groove, The stopper has a flange portion, which is arranged on the axial side of the first protrusion and extends in the radial direction. The dynamic pressure groove comprises: a first groove extending radially inward as it moves toward one side in the circumferential direction; and The second groove extends radially outward as it moves toward one side in the circumferential direction. An axial end surface of the bearing is axially opposed to an axial end surface of the flange portion via a fluid. The first dynamic pressure generating groove is arranged on one of the axial end surface of the bearing and the other axial end surface of the flange portion. The other axial end surface of the bearing is axially opposed to the one axial end surface of the rotor cover via the fluid. The second dynamic pressure generating groove is disposed on one of the other axial end surface of the bearing and the one axial end surface of the rotor cover.

3. The motor according to claim 1, characterized in that The rotor further includes a cylindrical wall portion that protrudes from the rotor cover portion in one axial direction and surrounds the other axial end portion of the bearing.

4. The motor according to claim 3, characterized in that The invention also comprises a cylindrical bearing retainer, which extends in the axial direction and surrounds and retains the bearing. The bearing cage further surrounds at least one axial side of the wall portion.

5. The motor according to claim 1, characterized in that The rotor further includes a second protrusion that protrudes from the rotor cover toward the other axial direction and extends along the central axis. When viewed in the axial direction, the outer diameter of the second protrusion is larger than the outer diameter of the first protrusion.

6. The motor according to claim 5, characterized in that When viewed in the axial direction, the outer diameter of the second protrusion is larger than the outer diameter of the bearing.

7. A fan motor, characterized in that: A motor according to claim 1 is provided.

8. The fan motor according to claim 7, characterized in that: The device further comprises an impeller which is rotatable together with the rotor of the motor about the central axis. The rotor further includes a rotor cylinder portion extending in one axial direction from a radially outer end portion of the rotor cover portion. The impeller is fixed to the rotor cover and the rotor tube.

9. A fan motor, characterized in that: have: The motor according to claim 5; and an impeller rotatable together with the rotor of the motor about the central axis and fixed to at least the rotor cover of the rotor, The impeller has an impeller cover portion, which is in an annular shape surrounding the second protrusion and is arranged on the other axial end surface of the rotor cover portion. The other axial end portion of the second protrusion of the motor is arranged on the other axial side relative to the radially inner end portion of the impeller cover portion.

10. The fan motor according to claim 8 or 9, characterized in that: In the axial direction, the upper surface of the rotor cover portion faces the impeller via a circular gap surrounding the central axis.

11. The fan motor according to claim 8 or 9, characterized in that: The material of the impeller is polycarbonate resin.

Images