Motor and air supply device

Abstract

A housing of a motor has a bearing holder that holds a bearing that rotatably supports a shaft. The magnet and one axial end portion of a shaft formed by a magnetic body face each other in the axial direction. The yoke is composed of a magnetic body, and at least a part of the yoke is disposed on one side of the magnet in the axial direction. The first contact portion of the housing is disposed radially outward of the magnet and is in contact with at least a portion of the other axial end face of the yoke. The second contact portion is in contact with at least a part of one axial end face of the yoke.

Description

Technical Field

[0001] The invention relates to a motor and an air supply device. Background Art

[0002] In the past, there is a known technology that makes the axial end of the shaft face the magnet in the axial direction and uses magnetic force to suppress the movement of the shaft. For example, a brushless motor has: a bearing hub, the inner circumference of which is fixed with a bearing; a shaft (i.e., an axle), which is held by the bearing so as to rotate freely; a thrust bearing member, which slides with the end face of the shaft; a permanent magnet, which clamps the thrust bearing member and attracts the end face of the shaft in the thrust direction; and a bottom bearing portion, which supports the permanent magnet. The bearing hub, the bearing, the shaft, and the bottom bearing portion are made of magnetic material, and a closed magnetic circuit clamping the thrust bearing member is formed in the order of the permanent magnet, the bottom bearing portion, the bearing hub, the bearing, and the shaft. In addition, in order to alleviate the magnetic saturation at the bottom bearing portion, a space portion is provided at the outer periphery of the permanent magnet. (For example, refer to Japanese Patent Gazette No. 2005-192262)

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2005-192262 Summary of the invention

[0006] Problems to be solved by the invention

[0007] However, if a wider space is provided radially outside the permanent magnet, the bottom receiving portion of the magnetic body is likely to vibrate axially together with the permanent magnet in accordance with the movement of the shaft. Therefore, the shaft is likely to move axially, which may affect the rotation accuracy of the motor.

[0008] An object of the present invention is to suppress axial vibration of a yoke of a magnet that magnetically attracts a shaft.

[0009] Solutions to Solve Problems

[0010] An exemplary motor of the present invention includes a rotor that rotates around a central axis extending in an axial direction. The motor includes a shaft, a bearing, a housing, a magnet, and a yoke. The shaft is made of a magnetic body and extends along the central axis. The bearing is capable of rotatably supporting the shaft. The housing has a bearing retainer that retains the bearing. The magnet is axially opposed to one axial end of the shaft. The yoke is made of a magnetic body, and at least a portion is arranged on one axial side of the magnet. The housing has a first contact portion and a second contact portion. The first contact portion is arranged at a position radially outward of the magnet and contacts at least a portion of the other axial end surface of the yoke. The second contact portion contacts at least a portion of one axial end surface of the yoke.

[0011] Furthermore, an air blowing device according to an example of the present invention includes the above-mentioned motor and an impeller. The impeller is fixed to the rotor.

[0012] Effects of the Invention

[0013] According to the motor and the air blower of the example of the present invention, it is possible to suppress the vibration of the yoke of the magnet that magnetically attracts the shaft in the axial direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a cross-sectional view showing a configuration example of the air supply device according to the present embodiment.

[0015] Figure 2A It is a cross-sectional view showing a structural example of a magnetic attraction portion.

[0016] Figure 2B It is a cross-sectional view showing another structural example of the magnetic attraction portion.

[0017] Figure 3A It is a perspective view showing a structural example of the yoke plate portion.

[0018] Figure 3B It is a perspective view showing another structural example of the yoke plate portion.

[0019] Figure 4 This is a graph showing an example of changes in the attractive force with respect to the diameter of the yoke plate portion. DETAILED DESCRIPTION

[0020] Exemplary embodiments will be described below with reference to the accompanying drawings.

[0021] In addition, in this specification, the direction parallel to the central axis CA is referred to as the "axial direction". The direction from the rotor cover 12 described later toward the base 31 in the axial direction is referred to as the "one axial direction D1", and the direction from the base 31 toward the rotor cover 12 is referred to as the "other axial direction D2". In addition, the direction orthogonal to the central axis CA is referred to as the "radial direction", and the rotation direction centered on the central axis CA is referred to as the "circumferential direction". The direction close to the central axis CA in the radial direction is referred to as the "radial inner side Di", and the direction away from the central axis CA is referred to as the "radial outer side Do".

[0022] In addition, in this specification, "annular" includes a shape that is connected continuously without gaps in the entire area of ​​the circumference centered on the central axis CA, and also includes a shape that has one or more gaps in a part of the entire area centered on the central axis CA. In addition, "annular" 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.

[0023] 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 wherever 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 each other 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 the positional relationship between the two is angularly offset to a degree that does not deviate from the main purpose of the present invention.

[0024] In addition, these names are used only for explanation, and are not intended to limit actual positional relationships, directions, names, etc.

[0025] <1. Air supply device 100>

[0026] Figure 1 2 is a cross-sectional view showing a structural example of the air supply device 100 according to the present embodiment. Figure 1 As shown, the air supply device 100 is an axial flow fan, and the air flow F sucked from the air inlet 1031 and flowing in the wind tunnel 1032 is sent out from the exhaust port 1033 to the axial direction D1. However, this example does not exclude that the air supply device 100 is a structure other than an axial flow fan. For example, the air supply device 100 can also be a centrifugal fan.

[0027] The air blowing device 100 includes a motor 101 , an impeller 102 , an outer cylinder portion 103 , and stationary blades 104 .

[0028] The motor 101 drives the impeller 102 to rotate.

[0029] The impeller 102 is fixed to the rotor 1 described later of the motor 101 and can rotate together with the rotor 1. The impeller 102 has a hub 1021 and moving blades 1022. The hub 1021 is a covered cylindrical shape extending in the axial direction, and is arranged at the other axial end of the rotor 1 and the shaft 11. The cylindrical portion of the hub 1021 is arranged on the radial outer side of the rotor cylindrical portion 13 described later. The moving blades 1022 extend from the radial outer end of the cylindrical portion of the hub 1021 to the radial outer side Do. The moving blades 1022 can rotate in the circumferential direction around the central axis CA extending in the axial direction.

[0030] The outer cylinder 103 is cylindrical and extends in the axial direction, surrounding the motor 101 and the impeller 102. A wind tunnel 1032 for the airflow F to pass through is formed between the outer cylinder 103, the motor 101 and the impeller 102. The other axial end of the outer cylinder 103 is open, and functions as an air intake port 1031. Through the rotation of the impeller 102, the air outside the air supply device 100 flows into the wind tunnel 1032 from the air intake port 1031. One axial end of the outer cylinder 103 is open, and an exhaust port 1033 is formed between the outer cylinder 103 and one axial end of the motor 101. The airflow F passing through the wind tunnel 1032 is sent out from the exhaust port 1033 to one axial direction D1.

[0031] The stationary blades 104 are arranged circumferentially at a position D1 closer to the moving blades 1022 of the impeller 102 in the axial direction. The stationary blades 104 connect the motor 101 and the outer cylinder 103 and extend in the axial direction. The stationary blades 104 rectify the airflow F flowing in the wind tunnel 1032.

[0032] <1-1. Motor 101>

[0033] Next, refer to Figure 1 The structure of the motor 101 will be described. The motor 101 includes a rotor 1 rotatable about a central axis CA extending in the axial direction. The motor 101 also includes a stator 2 , a housing 3 , a bearing 4 , a substrate 5 , and a magnetic attraction unit 6 .

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

[0035] The rotor 1 has a shaft 11, a rotor cover 12, a rotor cylinder 13, a rotor yoke 14, and a rotor magnet 15. The shaft 11 is made of a magnetic body and extends along the central axis CA. The motor 101 has a shaft 11. The shaft 11 can rotate around the central axis CA. The rotor cover 12 extends from the shaft 11 to the radially outer side Do. The rotor cylinder 13 extends from the radially outer end of the rotor cover 12 to the axial direction D1, surrounding the stator 2. The rotor yoke 14 is arranged on the radially inner side of the rotor cylinder 13, and is cylindrical in the axial direction in the present embodiment. However, it is not limited to this example, and the rotor yoke 14 can also be composed of a plurality of yoke pieces. The plurality of yoke pieces are plate-shaped and extend in the axial direction, and a plurality of them are arranged in the circumferential direction. The rotor magnet 15 is arranged on the radially inner side of the rotor yoke 14. In the rotor magnet 15, different magnetic poles (N poles and S poles) are arranged alternately in the circumferential direction. The rotor magnet 15 may be in an annular shape surrounding the central axis CA, or may be composed of a plurality of magnet pieces arranged in the circumferential direction.

[0036] <1-1-2. Stator 2>

[0037] The stator 2 is arranged at a position closer to the radial inner side Di than the rotor magnet 15. The stator 2 has a stator core 21, an insulator 22, and a coil portion 23. The stator core 21 is made of a magnetic body, and in the present embodiment is a laminated body of a plurality of plate-shaped electromagnetic steel plates laminated in the axial direction. The stator core 21 is radially opposed to the rotor magnet 15. The insulator 22 is made of an electrically insulating material such as resin, and is arranged on the surface of the stator core 21. The coil portion 23 is arranged on the stator core 21, and a plurality of coil portions are arranged in the circumferential direction. The coil portion 23 is a component in which a conductive wire (icon omitted) is arranged on the stator core 21 via an insulator 22. The conductive wire is, for example, an enameled copper wire, a metal wire covered by an insulating component, or the like. When a driving current is supplied to the coil portion 23, the stator 2 is excited and the rotor 1 is driven.

[0038] <1-1-3. Housing 3>

[0039] The housing 3 has a base portion 31, a peripheral wall portion 32, a bearing holder 33, a first contact portion 34, and a second contact portion 35. In addition, in the present embodiment, the base portion 31, the peripheral wall portion 32, the bearing holder 33, the first contact portion 34, and the second contact portion 35 are made of resin, and are integrally formed together with the yoke 63 of the magnetic attraction portion 6 described later, for example, by casting using a mold. However, this example does not exclude a structure in which at least any one of the base portion 31, the peripheral wall portion 32, the bearing holder 33, the first contact portion 34, and the second contact portion 35 is another component, nor does it exclude a structure in which at least any one of them is formed of a material other than resin (for example, a metal material such as aluminum or its alloy). In addition, this example does not exclude a structure in which the housing 3 is formed by a method other than casting using a mold.

[0040] The base portion 31 is a plate-shaped portion extending from the central axis CA toward the radially outer side Do, and is arranged at a position closer to one axial side D1 than the stator 2 and the substrate 5. The peripheral wall portion 32 protrudes from the radially outer end portion of the base portion 31 toward the other axial side D2, and extends in the circumferential direction. In the present embodiment, the peripheral wall portion 32 is annular and surrounds the central axis, and holds the substrate 5. The bearing retainer 33 is a cylindrical shape extending in the axial direction, and protrudes from the radially inner side Di side of the base portion 31 toward the other axial side D2. The bearing retainer 33 holds the stator 2. In detail, the stator core 21 is fixed to the bearing retainer 33. In addition, the shaft 11 is inserted into the bearing retainer 33. The bearing retainer 33 holds the bearing 4. The first contact portion 34 and the second contact portion 35 will be described later.

[0041] In addition, it is preferred that the housing 3 further has a platform 331. The platform 331 is arranged at the radial outer end of one axial end of the bearing retainer 33 and extends in the circumferential direction. The platform 331 expands toward the radial outer side Do as it moves toward the axial direction D1, and is connected to the base 31. However, this example does not exclude a structure in which the housing 3 does not have the platform 331.

[0042] <1-1-4. Bearing 4>

[0043] The bearing 4 is cylindrical and surrounds the shaft 11, and extends in the axial direction. The bearing 4 is a sliding bearing, and is disposed on the radially inner surface of the bearing holder 33. The bearing 4 supports the shaft 11 rotatably.

[0044] Preferably, the material of the bearing 4 is a non-magnetic body. By making the material of the bearing 4 a non-magnetic body, the attraction force Ps of the magnet 61 on the shaft 11 can be increased compared to the case where the bearing 4 is a magnetic body. In addition, the attraction force Ps is the magnitude of the force with which the magnetic attraction portion 6 (especially the magnet 61 described later) attracts the shaft 11 of the magnetic body in the axial direction D1 through its magnetic force. When the impeller 102 is driven, the shaft 11 is easy to separate from the magnet 61 in the axial direction. When the axial spacing between the two becomes larger, this effect (the effect of increasing the attraction force Ps of the magnet 61 when the material of the bearing 4 is a non-magnetic body compared to the case where the bearing 4 is a magnetic body) works more effectively. Therefore, the separation of the shaft 11 relative to the magnet 61 can be more effectively suppressed or prevented.

[0045] <1-1-5.Substrate 5>

[0046] The substrate 5 is arranged at a position closer to one axial direction D1 than the stator 2, and extends from the radial inner side surface of the peripheral wall portion 32 to the radial inner side Di and expands in the circumferential direction (see Figure 1 ). The substrate 5 carries various electronic components such as a stator drive circuit. In addition, an external connection line (not shown) is electrically connected to the substrate 5. The external connection line is a connection line that is led to the outside of the air supply device 100 and electrically connects the substrate 5 to an external device (such as an external power supply) of the air supply device 100.

[0047] <1-1-6. Magnetic attraction unit 6>

[0048] Next, refer to Figure 1 and FIG. 2A to FIG. 2B , explaining the magnetic attraction part 6. Figure 2A It is a cross-sectional view showing a structural example of the magnetic attraction portion 6 . Figure 2B It is a cross-sectional view showing another configuration example of the magnetic attraction portion 6 . Figure 2A and Figure 2B Corresponds to Figure 1 The cross-sectional structure of part II surrounded by the dashed line.

[0049] The magnetic attraction portion 6 includes a magnet 61, a thrust plate 62, and a yoke 63. In other words, the motor 101 includes a magnet 61, a thrust plate 62, and a yoke 63. The magnetic attraction portion 6 attracts the shaft 11 in one axial direction D1 by the magnetic force of the magnet 61, and suppresses the movement of the shaft 11 in the other axial direction D2. In addition, even if the shaft moves away from the magnet 61 in the other axial direction D2, the shaft 11 can be pulled back in the one axial direction D1 by the magnetic force.

[0050] The magnet 61 is a columnar permanent magnet extending in the axial direction, and is arranged at a position D1 closer to one axial side than the shaft 11 and the bearing 4. The magnet 61 is arranged on the other axial end surface of the yoke 63, and in particular, on the other axial end surface of the yoke plate portion 631 described later. The magnet 61 is axially opposed to the axial end portion of the shaft 11.

[0051] The thrust plate 62 is a plate-shaped plate extending radially from the central axis CA, and is disposed at the other axial side D2 of the magnet 61. Specifically, the thrust plate 62 is disposed between the magnet 61, the bearing 4, and the shaft 11. The thrust plate 62 is made of a material with high sliding properties, and is in contact with one axial end portion of the bearing 4 and one axial end portion of the shaft 11. However, this example does not exclude a structure in which the thrust plate 62 does not contact one axial end portion of the bearing 4.

[0052] The yoke 63 is made of a magnetic body. At least a portion of the yoke 63 is disposed on one axial direction D1 of the magnet 61. Figure 2A In the embodiment, the yoke 63 is in the shape of a plate extending in the radial direction. In other words, the yoke 63 is composed of only the yoke plate portion 631. In this way, the yoke 63 can be formed into a simple plate shape.

[0053] Preferably, the yoke plate portion 631 is arranged at a position D1 closer to the axial direction than the table portion 331 (see Figure 1 ). In this way, the vibration of the yoke 63 can be further suppressed, and the yoke 63 can be more reliably held. However, this example does not exclude a structure in which the yoke plate portion 631 is not arranged at a position closer to the one axial direction D1 than the platform portion 331 .

[0054] However, the shape of the yoke 63 is not limited to Figure 2A For example, Figure 2B As shown in FIG. 6 , the yoke 63 may also be in the shape of a bottomed cylinder. Figure 2BIn the figure, the yoke 63 has a yoke plate portion 631, a yoke cylinder portion 632, and a yoke flange portion 633. The yoke plate portion 631 is arranged at a position closer to one axial side D1 than the magnet 61, and extends in a direction perpendicular to the central axis CA. Preferably, the center of the yoke plate portion 631 observed from the axial direction coincides with the central axis CA. The yoke cylinder portion 632 is a cylinder extending from the radial outer end portion of the yoke plate portion 631 to the axial other side D2, and surrounds the magnet 61 at intervals in the radial direction. The yoke flange portion 633 extends from the axial other end portion of the yoke cylinder portion 632 to the radial outer side Do, and extends in the circumferential direction. Figure 2B The yoke 63 can be formed by, for example, press forming.

[0055] In order to facilitate understanding of the following contents, the yoke 63 is assumed to be Figure 2A The plate-like structure is described below.

[0056] <1-2. First contact portion 34 and second contact portion 35>

[0057] Next, as described above, the housing 3 also includes the first contact portion 34 and the second contact portion 35. The first contact portion 34 and the second contact portion 35 are part of the housing 3, specifically, for example, part of the base portion 31. Of the portion of the base portion 31 that overlaps with the yoke 63 when viewed from the axial direction, the first contact portion 34 is a portion that is disposed closer to the other axial direction D2 than the yoke 63 (particularly the yoke plate portion 631). Figure 2A The middle portion is arranged at a portion closer to the radial inner side Di than one axial end portion of the inner peripheral surface of the bearing retainer 33. Figure 2B The second contact portion 35 is located radially inward Di from the yoke tube portion 632. The second contact portion 35 is located axially D1 from the yoke 63 (particularly the yoke plate portion 631) and radially inward Di from the radial outer end of the yoke 63 (particularly the yoke plate portion 631).

[0058] The first contact portion 34 is arranged at a position closer to the radial outer side Do than the magnet 61, and contacts at least a portion of the other axial end surface of the yoke 63. The first contact portion 34 contacts the other axial end surface of the yoke 63 at a position closer to the radial outer side Do than the magnet 61. In addition, the first contact portion 34 contacts at least a portion of the radial outer side surface of the magnet 61 in the radial direction, and contacts the entire area of ​​the radial outer side surface of the magnet 61 in the present embodiment. Thus, the radial movement of the magnet 61 can be suppressed or prevented. However, this example does not exclude a structure in which the radial outer side surface of the magnet 61 does not contact the first contact portion 34.

[0059] Preferably, when viewed from the radial direction, at least a portion of the first contact portion 34 overlaps with the base portion 331. In other words, at least a portion of the first contact portion 34 is arranged at the same axial position as the stage portion 331. In this way, the radial thickness of the portion on the radially outer side Do in the housing 3 can be made thicker than the first contact portion 34. Therefore, the first contact portion 34 can more reliably hold the yoke 63, thereby further suppressing its vibration.

[0060] In addition, the first contact portion 34 is in contact with the thrust plate 62 in the axial direction. In this way, the thrust plate 62 can be stably arranged. However, this example does not exclude a structure in which the first contact portion 34 is not in contact with the thrust plate 62.

[0061] Here, the maximum axial thickness of the first contact portion 34 may be substantially the same as the axial thickness of the magnet 61. In addition, the thrust plate 62 may contact both the other axial end of the first contact portion 34 and the other axial end of the magnet 61. In this way, the thrust plate 62 can be stably arranged.

[0062] In addition, without being limited to the above example, the maximum axial thickness of the first contact portion 34 may be greater than the axial thickness of the magnet 61. In addition, the first contact portion 34 may be located radially outward of the thrust plate 62, or may be in contact with the radial outer end of the thrust plate 62. In this way, the radial movement of the thrust plate 62 can be suppressed or prevented by the first contact portion 34. Therefore, the thrust plate 62 can be stably arranged.

[0063] The second contact portion 35 contacts at least a portion of one axial end surface of the yoke 63. The second contact portion 35 covers the one axial end surface of the yoke 63.

[0064] In this way, the yoke 63 can be clamped and held in the axial direction by the first contact portion 34 and the second contact portion 35. When the separation of the shaft 11 relative to the magnetic attraction portion 6 is suppressed by the magnetic attraction of the magnet 61, the yoke 63 is affected by the attraction force Ps together with the magnet 61. Therefore, the yoke 63 is easily vibrated in the axial direction by the axial force acting on the yoke 63. The diameter W3 of the yoke 63 (see Figure 2A The larger the yoke 63 is, the easier it is to generate such vibration. Therefore, by holding the yoke 63 in the axial direction as described above, even if the yoke 63 is enlarged in the radial direction, the yoke 63 (especially the yoke plate portion 631) of the magnet 61 that magnetically attracts the shaft 11 can be suppressed from vibrating in the axial direction. Therefore, it is possible to suppress or prevent a reduction in the rotation accuracy of the motor 101.

[0065] Preferably, the housing 3 contacts at least a portion of the radially outer end of the yoke 63. In this way, the radial movement of the yoke 63 can be suppressed or prevented. Figure 2A and Figure 2BIn the embodiment, the plate-shaped yoke 63 is embedded in the base portion 31. Figure 2A In the embodiment, the radial outer end of the plate-shaped yoke 63 is covered and in contact with the base portion 31 of the housing 3. Figure 2B In the embodiment, the radially outer ends of the yoke plate portion 631, the yoke cylinder portion 632, and the yoke flange portion 633 are covered and contacted with the base portion 31 of the housing 3. Figure 2A and Figure 2B In the embodiment, the entire radial outer end of the yoke 63 (or its components 631 to 633) is in contact with the base portion 31 of the housing 3. However, the present invention is not limited to this example, and at least a portion of the radial outer end may not be in contact with the base portion 31. In other words, a gap may exist between at least a portion of the radial outer end and the base portion 31.

[0066] In addition, it is preferred that the maximum axial thickness W2 of the second contact portion 35 is greater than the maximum axial thickness W1 of the yoke plate portion 631. The axial thickness W2 is the thickness of a portion of the base portion 31 that is closer to the axial one side D1 than the yoke 63. The axial thickness W2 is the axial spacing between the other axial end surface of the above-mentioned portion (the end surface on the yoke 63 side) and the axial one end surface of the base portion 31. By making W2 ≥ W1, the thickness W2 of the second contact portion 35 that contacts the axial one end surface of the yoke 63 can be fully ensured. Therefore, the deflection amount of the yoke 63 in the axial one side D1 can be further reduced. Therefore, the vibration of the yoke 63 can be further suppressed, and the yoke 63 can be more reliably held between the first contact portion 34 and the second contact portion 35.

[0067] In addition, as described above, the material of the first contact part 34 and the second contact part 35 is resin. In this way, the yoke 63 can be integrally molded with the first contact part 34 and the second contact part 35 using resin. Therefore, the productivity of the housing 3 can be improved. In addition, this example does not exclude a structure in which the first contact part 34 and the second contact part 35 are not resin.

[0068] Preferably, the second contact portion 35 has a through hole 351. The through hole 351 is an example of the "first through hole" of the present invention, and extends from one axial end face of the second contact portion 35 to the other axial end face (the end face on the yoke 63 side). In addition, in the present embodiment, the through hole 351 penetrates the second contact portion 35 in the axial direction and is connected to the recess 65 arranged in the central part of one axial end face of the yoke plate portion 631. The through hole 351 is, for example, a trace of an insert used when the housing 3 is pulled out of the mold. When the mold is molded, by supporting the yoke 63 with an insert, the yoke 63 can be stably integrally molded with the first contact portion 34 and the second contact portion 35.

[0069] Preferably, the yoke 63 is embedded in the base portion 31 without protruding from the base portion 31. In this way, the yoke 63 and the base portion 31 can be stably integrally formed. On the other hand, if the yoke 63 protrudes from the base portion 31, the protruding portion may be damaged by an external force acting on it. Therefore, by preventing the yoke 63 from protruding from the base portion 31, the above concerns can be eliminated.

[0070] <1-3. Yoke 63>

[0071] Next, with reference to Figures 1 to 3B , the shape of the yoke 63 (in other words, the yoke plate portion 631) will be described. Figure 3A is a perspective view showing a structural example of the yoke plate portion 631. Figure 3B is a perspective view showing another structural example of the yoke plate portion 631.

[0072] In the present embodiment, as Figure 3A shows, when viewed from the axial direction, the yoke 63 is circular. However, it is not limited to this example, and the shape of the yoke 63 when viewed from the axial direction may not be circular. For example, when viewed from the axial direction, the yoke 63 may be polygonal. Preferably, it is rectangular, triangular, or hexagonal as Figure 3B shows. The plate-shaped yoke 63 is formed, for example, by blanking. By forming the yoke 63 into a polygon, the yield rate of blanking can be increased, and thus the productivity of the yoke 63 can be improved.

[0073] The diameter W3 of the yoke 63 is equal to or greater than the diameter W4 of the magnet 61. In addition, the diameter W3 is the minimum outer diameter in the radial direction of the plate-shaped yoke 63 when viewed from the axial direction. The diameter W4 is the maximum outer diameter in the radial direction of the magnet 61 when viewed from the axial direction. By making the diameter W3 of the yoke 63 larger than the diameter W4 of the magnet 61, the attractive force Ps of the magnet 61 on the shaft 11 can be increased.

[0074] For example, Figure 4 is a graph showing an example of the change in the attractive force Ps with respect to the diameter W3 of the yoke plate portion 631. As Figure 4 shows, it is preferable to increase the diameter W3 of the yoke 63. Preferably, the diameter W3 of the yoke 63 is equal to or greater than the inner diameter W5 of the bearing cage 33. By making W3 ≥ W5, the diameter W3 of the yoke 63 can be further increased. Therefore, the attractive force Ps of the magnet 61 relative to the shaft 11 can be further increased. However, this example does not exclude the structure where W3 < W5.

[0075] In addition, as Figure 3A and Figure 3BAs shown, the yoke 63 may also have a through hole 64 and at least one of the recesses 65 and 66. The through hole 64, for example, penetrates the yoke plate portion 631. The recess 65 is arranged on the axial end face of the yoke plate portion 631. The recess 65 can be arranged on one axial end face of the yoke plate portion 631 and be recessed in the other axial direction D2, or it can be arranged on the other axial end face of the yoke plate portion 631 and be recessed in the one axial direction D1. The recess 66 is a so-called cutout, which is arranged at the radially outer end portion of the yoke plate portion 631 and is recessed in the radially inner side Di. In addition, in the case where the yoke 63 has components other than the yoke plate portion 631 (for example, refer to Figure 2B ), any one of which may be arranged in the component. In this way, when the yoke 63 is integrally formed with the housing 3, a part of the housing 3 is accommodated in the through hole 64 and the recesses 65 and 66. The anchoring effect of the accommodated part can improve the holding force of the yoke 63 relative to the housing 3. Therefore, the vibration and movement of the yoke 63 can be further prevented.

[0076] <2. Others>

[0077] 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 arbitrarily within the scope of no contradiction.

[0078] <3. Conclusion>

[0079] Hereinafter, the embodiments described so far and their modifications will be summarized.

[0080] For example, the motor disclosed in this specification may have the following structure (first structure):

[0081] A motor having a rotor that rotates about a central axis extending in an axial direction, comprising:

[0082] a shaft, which is made of a magnetic body and extends along the central axis;

[0083] a bearing that rotatably supports the shaft;

[0084] a housing having a bearing retainer for retaining the bearing;

[0085] a magnet axially opposed to one axial end portion of the shaft; and

[0086] A yoke is made of a magnetic body, at least a portion of which is arranged on one axial side of the magnet.

[0087] The housing has:

[0088] a first contact portion disposed radially outward of the magnet and in contact with at least a portion of the other axial end surface of the yoke; and

[0089] The second contact portion contacts at least a portion of an axial end surface of the yoke.

[0090] In addition, the motor of the first structure may be of the following structure (second structure):

[0091] The housing is in contact with at least a portion of a radially outer end portion of the yoke.

[0092] In addition, the motor of the first or second structure may be of the following structure (third structure):

[0093] The yoke includes a yoke plate portion which is arranged on the axial side of the magnet and extends in a direction perpendicular to the central axis.

[0094] The maximum axial thickness of the second contact portion is greater than or equal to the maximum axial thickness of the yoke plate portion.

[0095] In addition, the motor of any one of the first to third structures may be configured as follows (fourth structure): the material of the first contact portion and the second contact portion is resin (fourth structure).

[0096] In addition, the motor of any one of the first to fourth structures may have the following structure (fifth structure):

[0097] One axial end surface of the yoke is covered by the second contact portion,

[0098] The second contact portion has a first through hole extending from one axial end surface of the second contact portion to the other axial end surface.

[0099] In addition, the motor of any one of the first to fifth structures may have the following structure (sixth structure):

[0100] The housing has a platform portion disposed at a radially outer end portion of one axial end portion of the bearing retainer.

[0101] The platform portion expands radially outward as it moves toward one axial direction and is connected to the other axial end surface of the base portion.

[0102] The yoke is arranged at a position closer to one side in the axial direction than the table portion.

[0103] In addition, the motor of any one of the first to sixth structures may have the following structure (seventh structure):

[0104] The yoke is in the shape of a plate extending in the radial direction.

[0105] In addition, the motor of any one of the first to seventh structures may have the following structure (eighth structure): when viewed from the axial direction, the yoke has a polygonal shape.

[0106] In addition, the motor of any one of the first to eighth structures may have the following structure (ninth structure):

[0107] The diameter of the yoke is greater than or equal to the diameter of the magnet.

[0108] In addition, the motor of any one of the first to ninth structures may have the following structure (tenth structure):

[0109] The diameter of the yoke is greater than the inner diameter of the bearing holder.

[0110] In addition, the motor having any one of the first to tenth structures may have the following structure (eleventh structure): the yoke has at least one of a second through hole and a recessed portion.

[0111] In addition, the motor of any one of the first to eleventh structures may have the following structure (twelfth structure):

[0112] The bearing is cylindrical and surrounds the shaft.

[0113] The material of the bearing is a non-magnetic body.

[0114] In addition, the air supply device disclosed in this specification includes:

[0115] A motor of any one of the first to twelfth structures; and

[0116] An impeller is fixed to the rotor.

[0117] Industrial Applicability

[0118] The present invention is useful for a device equipped with a motor that suppresses axial movement of a shaft by the attractive force of a magnet.

[0119] Explanation of symbols

[0120] 100—air supply device, 101—motor, 102—impeller, 1021—hub, 1022—moving blades, 103—outer cylinder, 1031—intake port, 1032—wind tunnel, 1033—exhaust port, 104—stationary blades, 1—rotor, 11—shaft, 12—rotor cover, 13—rotor cylinder, 14—rotor yoke, 15—rotor magnet, 2—stator, 21—stator core, 22—insulator, 23—coil, 3—housing, 31—base, 32—peripheral wall part, 33—bearing retainer, 331—table part, 34—first contact part, 35—second contact part, 351—through hole, 4—bearing, 5—substrate, 6—magnetic attraction part, 61—magnet, 62—thrust plate, 63—yoke, 631—yoke plate part, 632—yoke cylinder part, 633—yoke flange part, 64—through hole, 65, 66—recess, CA—center axis, F—airflow, D1—one axial side, D2—the other axial side, Di—radial inside, Do—radial outside.

Claims

1. A motor comprising a rotor that rotates about a central axis extending in an axial direction, the motor comprising: A shaft, which is made of a magnetic body and extends along the central axis; a bearing that rotatably supports the shaft; a housing having a bearing retainer for retaining the bearing; a magnet axially opposed to one axial end portion of the shaft; and a yoke, which is made of a magnetic body and at least a portion of which is arranged on one axial side of the magnet, The housing has: a first contact portion disposed radially outwardly of the magnet and in contact with at least a portion of the other axial end surface of the yoke; and The second contact portion contacts at least a portion of an axial end surface of the yoke.

2. The motor according to claim 1, characterized in that The housing is in contact with at least a portion of a radially outer end portion of the yoke.

3. The motor according to claim 1, characterized in that The yoke includes a yoke plate portion which is arranged on the axial side of the magnet and extends in a direction perpendicular to the central axis. The maximum axial thickness of the second contact portion is greater than or equal to the maximum axial thickness of the yoke plate portion.

4. The motor according to claim 1, characterized in that The material of the first contact portion and the second contact portion is resin.

5. The motor according to claim 1, characterized in that One axial end surface of the yoke is covered by the second contact portion, The second contact portion has a first through hole extending from one axial end surface of the second contact portion to the other axial end surface.

6. The motor according to claim 1, characterized in that The housing has a platform portion disposed at a radially outer end portion of one axial end portion of the bearing retainer. The platform portion expands radially outward as it moves toward the axial direction. The yoke is arranged at a position closer to one side in the axial direction than the table portion.

7. The motor according to claim 1, characterized in that The magnetic yoke is in the shape of a plate extending in the radial direction.

8. The motor according to claim 1, characterized in that When viewed from the axial direction, the yoke is polygonal.

9. The motor according to claim 1, characterized in that The diameter of the yoke is greater than or equal to the diameter of the magnet.

10. The motor according to claim 1, characterized in that The diameter of the yoke is greater than the inner diameter of the bearing holder.

11. The motor according to claim 1, characterized in that The yoke has at least one of a second through hole and a recessed portion.

12. The motor according to claim 1, characterized in that The bearing is cylindrical and surrounds the shaft. The material of the bearing is a non-magnetic body.

13. An air supply device, characterized in that: have: The motor according to any one of claims 1 to 12; and An impeller is fixed to the rotor.

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