Outer rotor type motor

Abstract

An outer rotor type motor having a rotor in which magnets are arranged on an inner peripheral surface of a cylindrical rotor yoke includes a motor shaft that rotatably supports the rotor, and a rotor mounting member having a base end portion that is provided so as to extend from an outer peripheral surface of the motor shaft toward an outer side in a radial direction, and an outer end portion that is formed so as to extend from an outer peripheral surface of the base end portion toward an outer side in the radial direction. The outer end portion is formed at a position closer to the inner peripheral surface of the rotor yoke than the outer peripheral surface of the motor shaft, and the rotor is mounted to the outer end portion.

Description

Technical Field

[0001] This invention relates to an external rotor type motor. Background Technology

[0002] Patent Document 1 discloses an external rotor type motor with the following structure: a rotor body 31 is mounted on a flange portion 43 integrally formed near a motor shaft 40, and an internal fan 70 is integrally mounted on the upper surface of the bottom 33 of the rotor body 31.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent No. 5931460 Specification Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] However, in the construction of Patent Document 1, the centrifugal force (load) generated by the magnet 35 located on the outer end side (inner side of the cylinder) of the rotor body 31 acts on the flange portion 43 formed near the motor shaft, which may reduce the reliability of the strength of the flange portion 43.

[0008] The purpose of this invention is to provide an external rotor motor with excellent strength and reliability.

[0009] means for solving problems

[0010] One aspect of the present invention is an external rotor type motor having a rotor formed by arranging magnets on the inner circumferential surface of a cylindrical rotor yoke, characterized in that...

[0011] This external rotor type motor has the following features:

[0012] The motor shaft supports the rotor for rotation; and

[0013] A rotor mounting member having a base end extending radially outward from the outer periphery of the motor shaft and an outer end formed radially outward from the outer periphery of the base end.

[0014] The outer end is formed at a position closer to the inner circumferential surface of the rotor yoke than the outer circumferential surface of the motor shaft, and the rotor is mounted on the outer end.

[0015] Invention Effects

[0016] According to the present invention, by forming the outer end for rotor mounting at a position closer to the inner circumferential surface of the rotor yoke than the outer circumferential surface of the motor shaft, the influence of centrifugal force (load) that may be generated by the rotation of the rotor can be reduced, providing an external rotor type motor with excellent strength and reliability.

[0017] Other features and advantages of the invention will become apparent from the following description with reference to the accompanying drawings. Furthermore, in the drawings, the same or identical structures are labeled with the same reference numerals. Attached Figure Description

[0018] Figure 1 This is a cross-sectional view showing the structure of the external rotor type motor according to the first embodiment.

[0019] Figure 2 This is an enlarged view showing the structure of the rotor mounting components.

[0020] Figure 3 This is a cross-sectional view showing the structure of the external rotor type motor according to the second embodiment.

[0021] Figure 4 This is a cross-sectional view showing the structure of the external rotor type motor according to the third embodiment.

[0022] Figure 5 This is a schematic diagram showing the state of the fan being installed at the external end.

[0023] Figure 6 This diagram illustrates the installation of the fan.

[0024] Figure 7 This is a schematic diagram showing the state of the rotor yoke mounted on the outer end.

[0025] Figure 8 This diagram illustrates the installation of the rotor yoke. Detailed Implementation

[0026] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The structural elements described in these embodiments are merely illustrative, and the present invention is not limited to these embodiments.

[0027] [First Implementation Method]

[0028] (Structure of an external rotor motor)

[0029] Figure 1 This is a cross-sectional view showing the structure of the external rotor type motor according to the first embodiment. For example... Figure 1As shown, the external rotor type motor 100 is an external rotor type motor having a rotor 30 formed by arranging a plurality of magnets 35 on the inner circumferential surface of a cylindrical rotor yoke 31. The motor shaft 10 is supported by bearings 82 and 84 disposed within the motor housing 60 and is rotatable. The plurality of magnets 35 disposed on the inner circumferential surface of the rotor yoke 31 are arranged to form alternating magnetic poles in the circumferential direction.

[0030] In this embodiment, the rotor mounting member 20 is integrally formed with the motor shaft 10. The rotor mounting member 20 has a base end portion 22 extending radially outward from the outer periphery of the motor shaft 10, and an outer end portion 24 extending radially outward from the outer periphery of the base end portion.

[0031] Here, with the distance from the center of the motor shaft 10 to the radial center of the outer end 24 (the yoke mounting member 37 described later) as the first distance (=D1 / 2=R1) and the distance from the center of the motor shaft 10 to the outer peripheral surface of the rotor yoke 31 as the second distance (=D2 / 2=R2), the outer end 24 is formed at a position that satisfies the relationship that the first distance (R1) > 0.5 × the second distance (R2).

[0032] That is, the outer end portion 24 (yoke mounting member 37) of the rotor mounting member 20 is formed at a position closer to the inner circumferential surface of the rotor yoke 31 than the outer circumferential surface (cylindrical portion 34) of the motor shaft 10 (first distance (R1) > 0.5 × second distance (R2)), and the rotor 30 is mounted on the outer end portion 24. The motor shaft 10 supports the rotor 30 so that it can rotate, and the rotor 30 mounted on the outer end portion 24 rotates by the rotation of the motor shaft 10.

[0033] By positioning the outer end 24 for mounting the rotor 30 closer to the inner circumferential surface (cylinder 34) of the cylindrical rotor yoke 31 than the outer circumferential surface of the motor shaft 10, the influence of centrifugal force (load) that may be generated by the rotation of the rotor can be reduced, providing an external rotor type motor with excellent strength and reliability.

[0034] (Detailed construction of rotor mounting component 20)

[0035] Figure 2 yes Figure 1The enlarged view of the rotor mounting member 20 shown in part A shows that the member thickness (wall thickness) of the base end portion 22 on the motor shaft 10 side is TH1, and the member thickness (wall thickness) of the base end portion 22 on the radially outward extending outer end portion 24 side is TH2. The wall thickness of the base end portion 22 in the axial direction (hereinafter also referred to as axial) of the motor shaft 10 gradually decreases from the outer periphery of the motor shaft 10 toward the radially outward outer end portion 24. This ensures the rigidity of the portion that forms the base of the outer end portion 24 for rotor mounting, while dispersing stress concentrations that may occur locally at the fixed end side of the base end portion 22 (the portion on the motor shaft 10 side) due to the rotation of the rotor 30.

[0036] By forming an outer end portion 24 radially outward from the outer periphery of the base end portion 22, which is formed to ensure rigidity and prevent stress concentration, the outer end portion 24 can be formed at a position closer to the inner peripheral surface (cylinder portion 34) of the cylindrical rotor yoke 31 than the outer peripheral surface of the motor shaft 10. As a result, the influence of centrifugal force (load) that may be generated by the rotation of the rotor 30 can be reduced, providing an outer rotor type motor with excellent strength and reliability.

[0037] like Figure 2 As shown, a stepped portion 26 with different wall thicknesses is formed along the axial direction of the motor shaft 10 between the base end 22 and the outer end 24. With the opening of the rotor yoke 31 fitted into the stepped portion 26, the rotor 30 is mounted to the outer end 24 by a yoke mounting member 37 (e.g., a screw). By utilizing the stepped portion 26 for the fitting, the positioning of the rotor 30 (rotor yoke 31) and the rotor mounting member 20 becomes easier, reducing axial errors during assembly. Furthermore, by configuring it as a fitting, the contact area between the rotor yoke 31, the outer end 24 of the rotor mounting member 20, and the base end 22 can be increased, thus distributing the load acting on the outer end 24 towards the base end 22 when the rotor 30 is mounted.

[0038] (Construction of rotor yoke 31)

[0039] Return to the instructions Figure 1 The cross-sectional structure of the rotor yoke 31 will be described. The cylindrical rotor yoke 31 has: a connecting portion 32, which is formed to coincide with the outer end portion 24; a cylindrical portion 34, which is formed to allow magnets 35 to be disposed along the inner circumferential surface; and a joining portion 38, which forms a plurality of bends between the connecting portion 32 and the cylindrical portion 34, thereby joining the connecting portion 32 and the cylindrical portion 34 via the plurality of bends.

[0040] The portion of the outer end 24 of the rotor mounting member 20 that contacts the connecting portion 32 is formed in a planar shape in a direction that intersects the axial direction relative to the motor shaft 10 (hereinafter also referred to as the vertical direction). The connecting portion 32 of the rotor yoke 31 is formed in a planar shape such that it coincides with the outer end 24 in the vertical direction. In addition, the cylindrical portion 34 of the rotor yoke 31 is formed in a cylindrical shape and is configured to allow multiple magnets 35 with alternating magnetic poles formed in the circumferential direction to be arranged on the inner circumferential surface of the cylindrical portion 34.

[0041] exist Figure 1 In the example shown, a plurality of bends 33 and 36 are formed between the joint 32 and the cylindrical portion 34, and the joint 38 is formed to join the joint 32 and the cylindrical portion 34 via the plurality of bends 33 and 36. Although an example of the joint 38 having two bends 33 and 36 as a plurality of bends is shown, the structure of the bends is not limited to this example, and more than two bends can also be formed.

[0042] The bending portion 36 (hereinafter also referred to as the "first bending portion") is formed such that the joint portion 38 is bent toward the cylindrical portion 34 at a predetermined first angle (obtuse angle) between the joint portion 32 formed in the vertical direction relative to the axial direction of the motor shaft 10 and the cylindrical portion 34 formed along the axial direction of the motor shaft 10 (formed substantially parallel to the axial direction of the motor shaft 10).

[0043] Furthermore, the bending portion 33 (hereinafter also referred to as the "second bending portion") is formed such that the joining portion 38, which is bent at a first angle (obtuse angle) through the bending portion 36 (first bending portion), is bent at a predetermined second angle (obtuse angle) in a manner that engages with the cylindrical portion 34.

[0044] In the bends 36 and 33, both the first and second angles are obtuse angles, which can be set based on the shape design of the rotor yoke 31 (the structure of the connecting part 32, the cylindrical part 34, etc.). That is, based on the structure of the connecting part 32, the cylindrical part 34, etc., the first and second angles in the connecting part 38 can be set to the same angle, or the first angle can be set to be larger than the second angle, or the first angle can be set to be smaller than the second angle. The connecting part 32 and the cylindrical part 34 are connected by the connecting part 38, so that the rotor yoke 31 is formed into a cylindrical shape in which one opening of the cylindrical part 34 is partially blocked.

[0045] exist Figure 1 In this motor housing 60, the stator 90 includes a stator core with a generally annular core body and multiple coils wound around the stator core. The stator 90 is fixed inside the motor housing 60 by a stator fastening member 92. With the stator 90 fixed inside the motor housing 60, the stator 90 and the magnet 35 disposed on the inner circumferential surface of the cylindrical portion 34 are in a facing state.

[0046] In the coils of the stator 90, drive current is supplied from an external motor control device (not shown) via cable 93 and electrical connection 95, and the rotor 30 rotates by the magnetic field generated by the drive current. In addition, the rotation information of the motor shaft 10 detected by the rotation detection element (not shown) is configured to be transmitted to the external control device.

[0047] (Mounting structure of rotor yoke 31)

[0048] Figure 7 This diagram schematically illustrates the state in which the rotor yoke 31 is mounted on the outer end 24 of the rotor mounting member 20. A through hole 39B is formed in the rotor yoke 31 for the yoke mounting member 37 (e.g., a screw) to be inserted. The through hole 39B is formed with a diameter larger than the diameter (thread diameter) of the yoke mounting member 37. The yoke mounting member 37 engages with the first engaging portion 29B (threaded hole) formed on the outer end 24, thereby mounting the rotor yoke 31 on the outer end 24.

[0049] Figure 8 ST81 indicates from Figure 7 The diagram shows the state of the rotor mounting member 20 (base end 22, outer end 24) formed on the motor shaft 10, viewed in the direction of arrow 71. In the outer end 24, a first engaging portion 29B (threaded hole) is formed in a concentric circle that can engage with the yoke mounting member 37 for mounting the rotor yoke 31 (rotor 30), and a second engaging portion 29A (threaded hole) that can engage with the fan mounting member 44 for mounting the fan 40.

[0050] By mounting the rotor yoke 31 and the fan 40 concentrically on the outer end 24 of the rotor mounting member 20, that is, by mounting the rotor yoke 37 and the fan 40 using the outer end 24 which is formed in a planar and annular shape, it is not necessary to provide a separate fan mounting part on the outer end 24 as a structure for mounting the fan 40, and the outer end 24 (the radial dimension of the outer end 24) can be miniaturized.

[0051] Figure 8 ST82 indicates from Figure 7 The diagram shows the state after the rotor yoke 31 has been installed on the outer end 24, as seen in the direction of arrow 71. An opening 32B is formed in the center of the rotor yoke 31, and a stepped portion 26 (… Figure 2 With the rotor yoke 31 (rotor 30) fitted into the opening 32B, it is mounted on the outer end 24. Figure 8 In ST82, the through hole 39A is formed to allow the fan mounting member 44, which mounts the fan 40 to the outer end 24, to pass through the rotor yoke 31. In the rotor yoke 31, through holes 39B are formed concentrically for the yoke mounting member 37 to pass through. Figure 7And a through hole 39A through which the fan mounting component 44 is inserted. The through hole 39A is similarly formed to the through hole 39B, with a diameter larger than the diameter (thread diameter) of the fan mounting component 44.

[0052] (Construction of a cooling fan)

[0053] The external rotor type motor 100 has a fan 70 (external fan) and a fan 40 (internal fan) as a cooling mechanism that utilizes the rotational driving force of the motor.

[0054] The fan 70 (external fan) is mounted to the motor shaft 10 by fastening members such as keys. The fan 40 (internal fan) and the rotor yoke 31 are formed concentrically. With the rotor yoke 31 mounted between the fan 40 and the outer end 24, the fan 40 is mounted to the outer end 24. The fan 40 is mounted to the outer end 24 by fan mounting members 44 such as screws.

[0055] On the side of the external rotor type motor 100, the motor cover 65 is mounted to the motor housing 60 by cover fastening member 66 (e.g., screws, etc.), and the fan 70 (external fan) is covered by the motor cover 65.

[0056] If the fan 40 (internal fan) and the fan 70 (external fan) rotate by the rotation of the motor shaft 10, the fan 40 (internal fan) circulates the air inside the external rotor type motor 100, cooling the rotor 30 and stator 90, etc.

[0057] Additionally, fan 70 (external fan) draws air from the intake opening (not shown) provided on motor cover 65 and delivers it to the outer wall (motor housing 60) of the external rotor type motor 100, cooling the outer wall of the external rotor type motor 100. The air delivered by fan 70 (external fan) (external cooling air) cools the outer wall of motor 100, and fan 40 (internal fan) promotes heat exchange between the internal circulating air circulating internally and the outer wall.

[0058] (Mounting structure of the cooling fan)

[0059] Figure 5 This diagram schematically illustrates the state in which the fan 40 is mounted on the outer end portion 24 of the rotor mounting member 20. A through hole 39A is formed in the rotor yoke 31 disposed between the outer end portion 24 and the fan 40 for the fan mounting member 44 (e.g., a screw) to be inserted. The fan mounting member 44 and the second engaging portion 29A (threaded hole) formed at the outer end portion 24 are also shown. Figure 8 The fan 40 is mounted on the outer end 24.

[0060] Figure 6 ST61 is from Figure 5The diagram shows the state of the fan 40 mounted on the outer end 24, as seen in the direction of arrow 51. Additionally, Figure 6 ST62 indicates from Figure 5 The diagram shows the state of the fan 40 unit as seen from the direction of arrow 51. A through hole 46 is formed in the fan 40 for the fan mounting member 44 to be inserted. Like the through hole 39A, the through hole 46 is formed with a diameter larger than the diameter (thread diameter) of the fan mounting member 44. Additionally, a notch 47 is formed in the fan 40, which is larger than the outer diameter of the yoke mounting member 37 to avoid contact with the yoke mounting member 37 on which the rotor yoke 31 is mounted to the outer end 24.

[0061] like Figure 6 As shown in ST61, with the rotor yoke 31 mounted to the outer end 24 via the yoke mounting member 37, the fan 40 is further mounted to the outer end 24 via the fan mounting member 44. With the fan 40 mounted to the outer end 24, the notch 47 avoids contact between the yoke mounting member 37 and the fan 40.

[0062] Since the yoke mounting member 37 and the fan 40 do not abut against each other, if the fan mounting member 44 is removed while the rotor yoke 31 is installed, only the fan 40 can be removed from the outer end 24. That is, while maintaining the state in which the rotor yoke 31 (rotor 30) is installed at the outer end 24 of the rotor mounting member 20, only the fan 40 can be removed from the outer end 24 of the rotor mounting member 20, thereby improving the maintainability of the external rotor motor.

[0063] like Figure 5 As shown, the fan 40 has a fan body 41 and a plurality of blade portions 42 arranged in the circumferential direction. When the fan 40 is mounted on the outer end 24, the blade portions 42 of the fan 40 are arranged in the space formed between the joint portion 38, which is bent by a plurality of bends 33 and bends 36, and the fan body 41.

[0064] For example, when the joint 32 is configured to extend linearly in the vertical direction without a bend in the joint 38, the space between the joint and the fan body 41 becomes narrow, limiting the size of the fan blades. If the size of the blades is configured to be similar to... Figure 1 Since the blade portion 42 is the same, the mounting position of the fan 40 is along the axial direction of the motor shaft 10. Figure 1 The paper is shifted to the right side, and the cooling mechanism is enlarged.

[0065] By arranging the blade portion 42 within the space formed by the bending of the joint portion 38 through multiple bends 33 and 36, the external rotor type motor 100 with a cooling mechanism utilizing the rotational drive force of the motor can be further miniaturized. Additionally, as... Figure 1 As shown, the joint 38 is bent by multiple bends 33 and 36, thereby expanding the space where the blade section 42 can be configured, making it more compact, and at the same time, the external rotor motor 100 can be cooled by the fan 40 with a larger blade section 42 and improved cooling performance.

[0066] [Second Implementation]

[0067] Figure 3 This is a cross-sectional view showing the structure of the external rotor type motor 100 according to the second embodiment. In the first embodiment, although an example was described where a fan 70 (external fan) and a fan 40 (internal fan) are arranged at one end of the motor shaft 10 as a cooling mechanism for the external rotor type motor 100, this is not limited to this example; other examples may also be used. Figure 3 As shown, fan 70 (external fan) is positioned at one end of motor shaft 10, and fan 40 (internal fan) is positioned at the other end of motor shaft 10. In this case, although the arrangement directions of rotor mounting member 20 and rotor 30 are relative to... Figure 1 Although the configuration direction is reversed, the same effect as the external rotor type motor 100 in the first embodiment can be achieved in this embodiment.

[0068] [Third Implementation Method]

[0069] Figure 4 This is a cross-sectional view showing the structure of the external rotor type motor 100 according to the third embodiment. In the first and second embodiments, for example, an example of the structure of the external rotor type motor 100 in which the rotor mounting member 20 is integrally formed on the motor shaft 10 by casting, cutting or the like has been described, but the rotor mounting member 20 and the motor shaft 10 may also be constructed as separate components.

[0070] In this case, for example, such as Figure 4 As shown, a tapered portion 11A is pre-set on the motor shaft 10, and a locking hole 11B that engages with the tapered portion 11A is provided on the rotor mounting member 20 side. The rotor mounting member 20 can be positioned at a predetermined position on the motor shaft 10 through the tapered portion 11A and the locking hole 11B.

[0071] exist Figure 4 In the example shown, although the fan 70 (external fan) is positioned at one end of the motor shaft 10 and the fan 40 (internal fan) is positioned at the other end of the motor shaft 10, it is also possible to... Figure 1 As shown, by placing the fan 70 (external fan) and the fan 40 (internal fan) on one end of the motor shaft 10, the same effect as the external rotor type motor 100 in the first embodiment can be achieved in this embodiment.

[0072] [Summary of Implementation Methods]

[0073] Structure 1. The external rotor type motor of the above embodiment has a cylindrical rotor yoke (e.g., Figure 1 Magnets are disposed on the inner circumferential surface of (e.g., 31) Figure 1 The rotor (e.g., 35) is formed by the rotor. Figure 1 30) external rotor type motor (e.g., Figure 1 (of 100),

[0074] This external rotor type motor (e.g., Figure 1 100) possesses:

[0075] Motor shaft (e.g., Figure 1 10), which supports the rotor (30) so that it can rotate; and

[0076] Rotor mounting components (e.g., Figure 1 20), which has a base end portion extending radially outward from the outer periphery of the motor shaft (10) (e.g., Figure 1 22) and the outer end formed from the outer periphery of the base end (22) toward the radially outward side (e.g., Figure 1 24),

[0077] The outer end portion (24) is formed at a position closer to the inner circumferential surface of the rotor yoke (31) than the outer circumferential surface of the motor shaft (10).

[0078] The rotor (10) is mounted on the outer end (24).

[0079] According to the external rotor type motor of structure 1, by forming the outer end 24 for mounting the rotor 30 at a position closer to the inner circumferential surface of the cylindrical rotor yoke 31 than the outer circumferential surface of the motor shaft 10, the influence of centrifugal force (load) that may be generated by the rotation of the rotor 30 can be reduced, providing an external rotor type motor with excellent strength and reliability.

[0080] Structure 2. In the external rotor type motor of the above embodiment, the base end (22) is formed such that the wall thickness of the motor shaft (10) in the axial direction gradually decreases from the outer periphery of the motor shaft (10) toward the outer end (24) in the radial direction.

[0081] According to the external rotor type motor of structure 2, the rotor mounting member 20 has a base end 22 formed as the axial wall thickness of the motor shaft gradually decreases towards the radially outer side, thereby ensuring the rigidity of the part that serves as the base of the outer end 24 for mounting the rotor 30, while dispersing the load (stress concentration) that may be generated locally at the fixed end side of the base end 22 (the part on the side of the motor shaft 10) due to the rotation of the rotor 30.

[0082] By forming the outer end from the outer periphery of the base end, which is formed to ensure rigidity and prevent stress concentration, towards the radially outer side, the outer end can be formed at a position closer to the inner periphery of the cylindrical rotor yoke than the outer periphery of the motor shaft. This reduces the influence of centrifugal force (load) that may be generated by the rotation of the rotor, providing an outer rotor type motor with excellent strength and reliability.

[0083] Structure 3. In the external rotor type motor of the above embodiment, a stepped portion is formed between the base end and the outer end along the axial direction of the motor shaft (e.g., Figure 2 26),

[0084] With the opening of the rotor yoke (31) engaged with the stepped portion (26), the rotor (30) is mounted on the outer end (24).

[0085] According to the external rotor type motor of structure 3, by utilizing the stepped sleeve (joined by segmented fitting), the positioning of the rotor 30 (rotor yoke 31) and the rotor mounting member 20 becomes easier, and the axial error during assembly can be reduced. In addition, by making it a sleeve, the contact area of ​​the outer end 24 and the base end 22 of the rotor yoke 31 and the rotor mounting member 20 can be increased, so that the load acting on the outer end 24 can be distributed to the base end 22 side when the rotor 30 is installed.

[0086] Structure 4. In the external rotor type motor of the above embodiment, the cylindrical rotor yoke (31) has:

[0087] Joint (e.g., Figure 1 32), which is formed to coincide with the outer end in a vertical direction that intersects the axial direction relative to the motor shaft;

[0088] cylindrical section (e.g., Figure 1 34), which is formed to allow the magnet to be arranged along the inner circumferential surface; and

[0089] Joint (e.g., Figure 1 38), which has a plurality of bends formed between the joint (32) and the cylindrical portion (34) (e.g., Figure 1 The connecting portion (32) and the cylindrical portion (34) are joined together via the plurality of curved portions (33, 36).

[0090] According to the external rotor type motor of structure 4, by providing multiple bends, the bending angle at each bend can be smoothly formed at an obtuse angle between the joint 32 and the cylinder 34. As a result, compared with the case of a right-angle bend between the joint 32 and the cylinder 34, the stress concentration inside the rotor yoke 31 can be further mitigated.

[0091] Structure 5. In the external rotor type motor of the above embodiment, a fan (e.g., formed concentrically with the rotor yoke (31) is also provided. Figure 1 40),

[0092] With the rotor yoke (31) mounted between the fan (40) and the outer end (24), the fan (40) is mounted on the outer end (24).

[0093] Structure 6. In the external rotor type motor of the above embodiment, a concentric circle is formed in the outer end (24) of a yoke mounting member (e.g., for mounting the rotor yoke) that can be mounted with the rotor yoke. Figure 7 , 8 37) The first engaging part of the engagement (e.g., Figure 8 29B) and a second engaging portion (e.g., capable of engaging with the fan mounting member (44) for mounting the fan (40). Figure 8 (29A).

[0094] According to the external rotor type motors of structures 5 and 6, by mounting the rotor yoke 31 and the fan 40 concentrically on the outer end 24 of the rotor mounting member 20, it is not necessary to provide a separate fan mounting part on the outer end 24 as a structure for mounting the fan 40, and the outer end 24 (the radial dimension of the outer end 24) can be miniaturized.

[0095] Structure 7. In the external rotor type motor of the above embodiment, through holes for the rotor mounting member (37) to be inserted are formed concentrically in the rotor yoke (31). Figure 7 39B) and a through hole through which the fan mounting member (44) is inserted (e.g., Figure 5 (39A).

[0096] According to the external rotor type motor of structure 7, the shape design of the rotor yoke 31 does not need to consider the configuration and cross-sectional shape constraints of the engagement portion for mounting the fan 40 to the rotor yoke 31. For example, when mounting the fan 40 to the rotor yoke 31, considering the engagement with the fastening member, it is easily subject to shape design limitations such as the need to form a bottom that extends in a straight line from the joint portion 32 of the rotor yoke 31.

[0097] By configuring the fan 40 to be mounted on the outer end 24 of the rotor mounting member 20, the degree of freedom in the shape design of the rotor yoke 31 can be increased. For example, it is possible to... Figure 1 As shown in the cross-sectional shape of the rotor yoke 31, multiple bends 33 and 36 are formed between the joint 32 and the cylindrical portion 34. Thus, the shape of the rotor yoke 31 can be set to a shape that can alleviate stress concentration.

[0098] Structure 8. In the external rotor type motor of the above embodiment, the cylindrical rotor yoke (31) has:

[0099] Joint (e.g., Figure 1 32), which is formed to coincide with the outer end along a vertical direction that intersects the axial direction relative to the motor shaft;

[0100] cylindrical section (e.g., Figure 1 34), which is formed to allow the magnet to be arranged along the inner circumferential surface; and

[0101] Joint (e.g., Figure 1 38), which forms a plurality of bends between the joint (32) and the cylindrical portion (34) (e.g., Figure 1 The cylindrical portion (34) of the connecting portion (32) is joined together via the plurality of curved portions (33, 36).

[0102] The blade portion of the fan (40) (for example, Figure 1 42) is disposed in the space formed between the joint (38) and the fan (40) which are bent by the plurality of bends (33, 36).

[0103] Structure 9. In the external rotor type motor of the above embodiment, the joint (38) has the following as the plurality of bent portions:

[0104] First curved portion (e.g., Figure 1 36), which is formed such that the joint (38) is bent at a first angle toward the cylindrical portion between the joint (32) formed in the vertical direction relative to the motor shaft (10) and the cylindrical portion (34) formed along the axial direction; and

[0105] The second curved section (for example, Figure 1 33), which is formed such that the joining portion (38), which is bent at the first angle through the first bending portion (36), is bent at the second angle so as to join with the cylindrical portion (34).

[0106] According to the external rotor type motors of structures 8 and 9, by arranging the blade portion 42 in the space formed by bending the joint portion 38, the external rotor type motor with a cooling mechanism (fan) that utilizes the rotational driving force of the motor can be further miniaturized.

[0107] In addition, the joint 38 is bent by multiple bends 33 and 36, thereby expanding the space where the blade section 42 can be configured, making it more compact, and at the same time, the external rotor motor 100 can be cooled by the fan 40 with a larger blade section 42 and improved cooling performance.

[0108] Structure 10. In the external rotor type motor of the above embodiment, a notch is formed in the fan (40) (for example, Figure 6 47), the notch (e.g., Figure 6 47) is formed to avoid contact with the yoke mounting member (37) on which the rotor yoke (31) is mounted at the outer end (24).

[0109] According to the external rotor type motor of structure 10, the fan 40 can be removed from the external end 24 of the rotor mounting member 20 while maintaining the state of the rotor yoke 31 (rotor 30) mounted on the outer end 24 of the rotor mounting member 20. This improves the maintainability of the external rotor type motor.

[0110] Structure 11. In the external rotor type motor of the above embodiment,

[0111] With the first distance being the distance from the center of the motor shaft to the radial center of the outer end, and the second distance being the distance from the center of the motor shaft to the outer peripheral surface of the rotor yoke,

[0112] The outer end is installed at a position that satisfies the relationship that the first distance > 0.5 × the second distance.

[0113] According to the external rotor type motor of structure 11, by forming the outer end 24 for mounting the rotor 30 at a position closer to the inner circumferential surface of the cylindrical rotor yoke 31 than the outer circumferential surface of the motor shaft 10 (first distance > 0.5 × second distance), the influence of centrifugal force (load) that may be generated by the rotation of the rotor 30 can be reduced, providing an external rotor type motor with excellent strength and reliability.

[0114] This invention is not limited to the embodiments described above, and various modifications and variations can be made without departing from the spirit and scope of this invention. Therefore, in order to disclose the scope of this invention, the following claims are appended.

[0115] Explanation of reference numerals in the attached figures

[0116] 10: Motor shaft; 11A: Tapered portion; 11B: Engaging hole; 20: Rotor mounting component; 22: Base end; 24: Outer end; 30: Rotor; 31: Rotor yoke; 32: Joint; 33: Bending portion (second bending portion); 34: Cylindrical portion; 35: Magnet; 36: Bending portion (first bending portion); 37: Rotor mounting component; 38: Joint; 39A: Through hole; 39B: Through hole; 40: Fan; 41: Fan body; 42: Blade portion; 44: Fan mounting component; 47: Notch portion; 100: External rotor type motor.

Claims

1. An external rotor type motor, comprising a rotor having magnets disposed on the inner circumferential surface of a cylindrical rotor yoke and a stator disposed on the inner circumferential side of the rotor yoke, characterized in that, The external rotor type motor has the following features: The motor shaft is configured to rotate integrally with the rotor; A rotor mounting member has a base end extending radially outward from the outer periphery of the motor shaft and an outer end formed radially outward from the outer periphery of the base end, and the rotor yoke is mounted on the outer end. The first fan (40) and the second fan (70), as mechanisms for circulating air using the rotational driving force of a motor, are configured to rotate integrally with the rotor yoke; and The motor housing, which houses the rotor and the stator. The first fan is configured to be fixed to the outer end of the rotor mounting member in a manner that allows it to rotate integrally with the motor shaft, and is disposed inside the motor housing to circulate air within the motor housing. The second fan is configured to be fixed in a manner that allows it to rotate integrally with the motor shaft, and is disposed on the outside of the motor housing and on the inside of a motor cover mounted on the outside of the motor housing, thereby circulating air inside the motor cover. The outer end is formed at a position closer to the inner circumferential surface of the rotor yoke than the outer circumferential surface of the motor shaft.

2. The external rotor type motor according to claim 1, characterized in that, The wall thickness of the base end portion, which is formed as the axial length of the motor shaft, gradually decreases from the outer periphery of the motor shaft toward the radially outer outer end portion.

3. The external rotor type motor according to claim 1 or 2, characterized in that, A stepped portion is formed between the base end and the outer end, along the axial direction of the motor shaft. With the opening of the rotor yoke engaged with the stepped portion, the rotor is mounted on the outer end.

4. The external rotor type motor according to claim 1, characterized in that, The rotor yoke is mounted between the first fan and the outer end, and the first fan is mounted on the outer end on which the rotor yoke is mounted.

5. The external rotor type motor according to claim 4, characterized in that, In the outer end portion, a first engaging portion that can engage with a yoke mounting member for mounting the rotor yoke and a second engaging portion that can engage with a fan mounting member for mounting the first fan are integrally rotated.

6. The external rotor type motor according to claim 5, characterized in that, In the rotor yoke, the through hole through which the rotor mounting component is inserted and the through hole through which the fan mounting component is inserted are formed as a single unit for rotation.

7. The external rotor type motor according to claim 1, characterized in that, The cylindrical rotor yoke has: The joint is formed to coincide with the outer end portion along a vertical direction that intersects the axial direction relative to the motor shaft; A cylindrical portion, which is configured to allow the magnet to be disposed along its inner circumferential surface; and A joint portion, which joins the joint portion to the cylindrical portion by a plurality of bends formed between the joint portion and the cylindrical portion. The first fan has a fan body and blades, the blades being disposed in a space formed between the joint and the fan body.

8. The external rotor type motor according to claim 7, characterized in that, As one of the plurality of curved portions, the joint portion has: The first bending portion is formed such that the joint portion, which is formed in the vertical direction relative to the axial direction of the motor shaft, and the cylindrical portion formed along the axial direction, bend the joint portion toward the cylindrical portion at a predetermined first angle; as well as The second bend is formed such that the joining portion, which bends at the first angle through the first bend, bends at a predetermined second angle to engage with the cylindrical portion.

9. The external rotor motor according to claim 1, characterized in that, In the first fan, a notch is formed to avoid contact with the yoke mounting member on which the rotor yoke is mounted to the outer end.

10. The external rotor motor according to claim 1 or 2, characterized in that, With the first distance being the distance from the center of the motor shaft to the radial center of the outer end, and the second distance being the distance from the center of the motor shaft to the outer peripheral surface of the rotor yoke, The outer end is installed at a position that satisfies the relationship that the first distance > 0.5 × the second distance.

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