Outer rotor type motor

Abstract

To provide an outer rotor type motor that has excellent cooling performance.SOLUTION: The outer rotor type motor has a rotor in which magnets are disposed in the inner peripheral surface of a cylindrical rotor yoke, and includes: a motor shaft for rotatably supporting the rotor; a rotor mounting member having a base end part extending radially outward from the outer periphery of the motor shaft and an outer end part formed radially outward from the outer periphery of the base end part; and a cooling mechanism using fans formed concentrically with the rotor yoke, the cooling mechanism including a first fan and a second fan.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an outer rotor motor. [Background technology]

[0002] Patent Document 1 discloses an outer rotor motor having a structure in which a rotor body 31 is attached to a flange portion 43 integrally formed near a motor shaft 40. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5931460 specification Summary of the Invention [Problem to be solved by the invention]

[0004] The outer rotor motor of Patent Document 1 has a structure in which a rotor body 31 is attached to a flange portion 43 integrally formed near the motor shaft 40, and an inner fan 70 is integrally attached to the upper surface of the bottom portion 33 of the rotor body 31.

[0005] An object of the present invention is to provide an outer rotor motor with excellent cooling performance. [Means for solving the problem]

[0006] An outer rotor motor according to one aspect of the present invention is an outer rotor motor having a rotor in which magnets are arranged on the inner circumferential surface of a cylindrical rotor yoke, a motor shaft that rotatably supports the rotor; a rotor mounting member having a base end portion extending radially outward from an outer periphery of the motor shaft, and an outer end portion extending radially outward from the outer periphery of the base end portion; a first fan and a second fan are provided as a cooling mechanism using fans formed concentrically with the rotor yoke; The cylindrical rotor yoke is a coupling portion formed to overlap the outer end portion along a vertical direction intersecting an axial direction of the motor shaft; a cylindrical portion formed so that the magnet can be arranged along an inner circumferential surface thereof; a joining portion that joins the joining portion and the tubular portion via a plurality of curved portions formed between the joining portion and the tubular portion, the blades arranged in the circumferential direction of the first fan body are arranged in a space formed between the joint portion curved by the plurality of curved portions and the first fan body, The rotor and the first fan are attached to the outer end by a fan attachment member, and the second fan is attached to a position on the axial end side of the motor shaft that is different in the axial direction from the position of the base end that extends from the outer periphery of the motor shaft. It is characterized by: [Effects of the Invention]

[0007] According to the present invention, when the first fan and the second fan rotate due to the rotation of the motor shaft, the first fan circulates air inside the outer rotor motor to cool the rotor, stator, etc. The second fan sends air taken in through an intake opening (not shown) provided in the motor cover toward the outer wall (motor housing) of the outer rotor motor, cooling the outer wall of the outer rotor motor. The air sent by the second fan (external cooling air) cools the outer wall of the outer rotor motor and also promotes heat exchange between the internal circulating air circulated inside by the first fan and the outer wall.

[0008] Other features and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings, in which the same or similar elements are designated by the same reference numerals. [Brief explanation of the drawings]

[0009] [Figure 1]1 is a cross-sectional view showing the configuration of an outer rotor motor according to a first embodiment. [Figure 2] FIG. 4 is an enlarged view showing the structure of the rotor mounting member. [Figure 3] FIG. 6 is a cross-sectional view showing the configuration of an outer rotor motor according to a second embodiment. [Figure 4] FIG. 10 is a cross-sectional view showing the configuration of an outer rotor motor according to a third embodiment. [Figure 5] FIG. 10 is a diagram showing a state in which a fan is attached to the outer end portion. [Figure 6] A diagram explaining how to install the fan. [Figure 7] FIG. 10 is a diagram schematically showing a state in which a rotor yoke is attached to the outer end portion. [Figure 8] FIG. 10 is a diagram illustrating the installation of the rotor yoke. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The components described in the embodiments are merely examples, and the present invention is not limited to the following embodiments.

[0011] [First embodiment] (Configuration of outer rotor motor) Fig. 1 is a cross-sectional view showing the configuration of an outer rotor motor according to a first embodiment. As shown in Fig. 1, outer rotor motor 100 is an outer rotor motor having a rotor 30 in which multiple magnets 35 are arranged on the inner circumferential surface of a cylindrical rotor yoke 31. Motor shaft 10 is rotatably supported by bearings 82 and 84 provided within motor housing 60. The multiple magnets 35 arranged on the inner circumferential surface of rotor yoke 31 are arranged to form magnetic poles that are alternately different in the circumferential direction.

[0012] In this embodiment, the rotor mounting member 20 is formed integrally with the motor shaft 10. The rotor mounting member 20 has a base end 22 extending radially outward from the outer periphery of the motor shaft 10, and an outer end 24 extending radially outward from the outer periphery of the base end.

[0013] Here, if the distance from the center of the motor shaft 10 to the radial center of the outer end 24 (yoke mounting member 37 described below) is defined as the first distance (= D1 / 2 = R1), and the distance from the center of the motor shaft 10 to the outer surface of the rotor yoke 31 is defined as the second distance (= D2 / 2 = R2), the outer end 24 is formed at a position that satisfies the relationship: first distance (R1) > 0.5 × second distance (R2).

[0014] That is, the outer end 24 (yoke mounting member 37) of the rotor mounting member 20 is formed at a position (first distance (R1) > 0.5 × second distance (R2)) closer to the inner circumferential surface of the rotor yoke 31 than the outer circumferential surface (cylinder 34) of the motor shaft 10, and the rotor 30 is mounted to the outer end 24. The motor shaft 10 rotatably supports the rotor 30, and the rotor 30 mounted to the outer end 24 rotates when the motor shaft 10 rotates.

[0015] By forming the outer end 24 to which the rotor 30 is attached closer to the inner surface (cylinder 34) of the cylindrical rotor yoke 31 than to the outer surface of the motor shaft 10, it is possible to reduce the effect of centrifugal force (load) that may be generated by the rotation of the rotor, and to provide an outer rotor type motor with excellent strength reliability.

[0016] (Detailed structure of rotor mounting member 20) 2 is an enlarged view of the structure of rotor mounting member 20 shown in part A in FIG. 1, in which base end 22 on the motor shaft 10 side has a material thickness (wall thickness) of TH1, and base end 22 on the radially outward extending outer end 24 side has a material thickness (wall thickness) of TH2. Base end 22 is formed so that its thickness in the axial direction of motor shaft 10 (hereinafter simply referred to as the axial direction) gradually decreases from the outer periphery of motor shaft 10 toward outer end 24, which is radially outward. This ensures the rigidity of the base portion of outer end 24 to which the rotor is attached, while dispersing stress concentrations that may occur locally at the fixed end side of base end 22 (the portion on the motor shaft 10 side) due to rotation of rotor 30.

[0017] By forming the outer end 24 radially outward from the outer periphery of the base end 22, which is formed so as to ensure rigidity and prevent stress concentration, it is possible to form the outer end 24 at a position closer to the inner periphery (cylinder 34) of the cylindrical rotor yoke 31 than to the outer periphery of the motor shaft 10.This reduces the effect of centrifugal force (load) that may be generated by the rotation of the rotor 30, making it possible to provide an outer rotor type motor with excellent strength reliability.

[0018] As shown in Fig. 2, a step 26 of varying thickness is formed between the base end 22 and the outer end 24 along the axial direction of the motor shaft 10. With the opening of the rotor yoke 31 fitted into the step 26, the rotor 30 is attached to the outer end 24 with a yoke attachment member 37 (e.g., a bolt). The spigot connection using the step 26 facilitates positioning of the rotor 30 (rotor yoke 31) and the rotor attachment member 20, reducing axial center errors during assembly. Furthermore, the spigot connection increases the contact area between the rotor yoke 31 and the outer end 24 and base end 22 of the rotor attachment member 20, allowing the load acting on the outer end 24 with the rotor 30 attached to be distributed toward the base end 22.

[0019] (Structure of rotor yoke 31) 1, the cross-sectional structure of rotor yoke 31 will be described. Cylindrical rotor yoke 31 has a connecting portion 32 formed to overlap outer end portion 24, a tubular portion 34 formed along its inner circumferential surface so that magnets 35 can be arranged, and a joining portion 38 formed between connecting portion 32 and tubular portion 34, with multiple curved portions joining connecting portion 32 and tubular portion 34 via the multiple curved portions.

[0020] The outer end 24 of the rotor mounting member 20 has a flat portion that comes into contact with the coupling portion 32 in a direction intersecting the axial direction of the motor shaft 10 (hereinafter also referred to as the vertical direction), and the coupling portion 32 of the rotor yoke 31 is also flat in the vertical direction so as to overlap with the outer end 24. The tubular portion 34 of the rotor yoke 31 is formed in a cylindrical shape, and a plurality of magnets 35, each having magnetic poles that are formed alternately in the circumferential direction, can be arranged on the inner circumferential surface of the tubular portion 34.

[0021] 1, a plurality of curved portions 33, 36 are formed between the connecting portion 32 and the tubular portion 34, and the joint portion 38 is formed to join the connecting portion 32 and the tubular portion 34 via the plurality of curved portions 33, 36. Although the joint portion 38 shows an example in which it has two curved portions 33, 36 as the plurality of curved portions, the configuration example of the curved portions is not limited to this example, and it is also possible to form two or more curved portions.

[0022] The curved portion 36 (hereinafter also referred to as the "first curved portion") is formed between the connecting portion 32, which is formed perpendicular to the axial direction of the motor shaft 10, and the tubular portion 34, which is formed along the axial direction of the motor shaft 10 (formed approximately parallel to the axial direction of the motor shaft 10), so as to curve the joint portion 38 at a predetermined first angle (obtuse angle) toward the tubular portion 34.

[0023] In addition, the curved portion 33 (hereinafter also referred to as the "second curved portion") is formed to be curved at a predetermined second angle (obtuse angle) so as to join the joint portion 38, which is curved at a first angle (obtuse angle) by the curved portion 36 (first curved portion), to the tubular portion 34.

[0024] In curved portions 36, 33, the first angle and the second angle are both obtuse angles and can be set based on the shape design of rotor yoke 31 (the structures of coupling portion 32, tubular portion 34, etc.). That is, based on the structures of coupling portion 32, tubular portion 34, etc., it is possible to set the first angle and the second angle at joint portion 38 to be the same angle, to set the first angle to be larger than the second angle, or to set the first angle to be smaller than the second angle. By connecting coupling portion 32 and tubular portion 34 with joint portion 38, rotor yoke 31 is formed into a cylindrical shape with one opening of tubular portion 34 partially closed.

[0025] 1, the stator 90 has a stator core having a substantially annular core body and a plurality of coils wound around the stator core, and 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 arranged on the inner circumferential surface of the cylindrical portion 34 face each other.

[0026] A drive current is supplied to the coil of the stator 90 from an external motor control device (not shown) via a cable 93 and an electrical connection part 95, and the magnetic field generated by the drive current rotates the rotor 30. Furthermore, rotation information of the motor shaft 10 detected by a rotation detection element (not shown) can be transmitted to the external control device.

[0027] (Rotor yoke 31 mounting structure) 7 is a diagram schematically illustrating the state in which rotor yoke 31 is attached to outer end 24 of rotor attachment member 20, with rotor yoke 31 having through-hole 39B formed therein for inserting yoke attachment member 37 (e.g., bolt). Through-hole 39B is formed with a hole diameter larger than the diameter (screw diameter) of yoke attachment member 37. Yoke attachment member 37 engages with first engagement portion 29B (screw hole) formed in outer end 24, attaching rotor yoke 31 to outer end 24.

[0028] ST81 in Fig. 8 is a diagram showing the rotor mounting member 20 (base end 22, outer end 24) formed on the motor shaft 10 as viewed from the direction of arrow 71 in Fig. 7. On the outer end 24, a first engagement portion 29B (screw hole) engageable with a yoke mounting member 37 for mounting the rotor yoke 31 (rotor 30), and a second engagement portion 29A (screw hole) engageable with a fan mounting member 44 for mounting the fan 40 are concentrically formed.

[0029] By attaching the rotor yoke 31 and the fan 40 concentrically to the outer end 24 of the rotor mounting member 20, that is, by attaching the rotor yoke 37 and the fan 40 using the outer end 24 which is formed in a flat and annular shape, there is no need to provide a separate fan mounting portion at the outer end 24 as a structure for attaching the fan 40, and it is possible to reduce the size of the outer end 24 (the radial dimension of the outer end 24).

[0030] ST82 in Fig. 8 is a diagram showing the state in which rotor yoke 31 is attached to outer end portion 24, as viewed from the direction of arrow 71 in Fig. 7. An opening 32B is formed in the center of rotor yoke 31, and rotor yoke 31 (rotor 30) is attached to outer end portion 24 with step portion 26 (Fig. 2) fitted into opening 32B. In ST82 in Fig. 8, through hole 39A is formed so that fan mounting member 44 for attaching fan 40 to outer end portion 24 can be inserted through rotor yoke 31. Rotor yoke 31 is concentrically formed with through hole 39B (Fig. 7) for inserting yoke mounting member 37 and through hole 39A for inserting fan mounting member 44. Like through hole 39B, through hole 39A is formed with a hole diameter larger than the diameter (screw diameter) of fan mounting member 44.

[0031] (Cooling fan structure) The outer rotor 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.

[0032] Fan 70 (external fan) is attached to motor shaft 10 with fastening members such as keys. Fan 40 (internal fan) is formed concentrically with rotor yoke 31, and is attached to outer end portion 24 with rotor yoke 31 attached between fan 40 and outer end portion 24. Fan 40 is attached to outer end portion 24 with fan attachment members 44 such as bolts.

[0033] A motor cover 65 is attached to the side of the outer rotor motor 100 by a cover fastening member 66 (for example, a bolt) to the motor housing 60, and the motor cover 65 covers the fan 70 (external fan).

[0034] When the fan 40 (internal fan) and the fan 70 (external fan) rotate due to the rotation of the motor shaft 10, the fan 40 (internal fan) circulates the air inside the outer rotor motor 100 to cool the rotor 30, the stator 90, etc.

[0035] Furthermore, fan 70 (external fan) sends air taken in through an intake opening (not shown) provided in motor cover 65 toward the outer wall (motor housing 60) of outer rotor motor 100, cooling the outer wall of outer rotor motor 100. The air (external cooling air) sent by fan 70 (external fan) cools the outer wall of motor 100 and also promotes heat exchange between the outer wall and the internal circulating air circulated inside by fan 40 (internal fan).

[0036] (Cooling fan mounting structure) 5 is a diagram schematically illustrating the state in which the fan 40 is attached to the outer end 24 of the rotor attachment member 20, and the rotor yoke 31, which is disposed between the outer end 24 and the fan 40, has a through-hole 39A through which a fan attachment member 44 (e.g., a bolt) is inserted. The fan attachment member 44 engages with a second engagement portion 29A (screw hole: FIG. 8) formed in the outer end 24, and the fan 40 is attached to the outer end 24.

[0037] ST61 in Fig. 6 is a diagram showing the fan 40 attached to the outer end 24 as viewed from the direction of arrow 51 in Fig. 5. ST62 in Fig. 6 is a diagram showing the fan 40 alone as viewed from the direction of arrow 51 in Fig. 5. The fan 40 is formed with a through hole 46 through which the fan mounting member 44 is inserted. Like the through hole 39A, the through hole 46 is formed with a diameter larger than the diameter (screw diameter) of the fan mounting member 44. The fan 40 is also formed with a cutout portion 47 that is formed larger than the outer diameter of the yoke mounting member 37 that attaches the rotor yoke 31 to the outer end 24 so as to avoid contact with the yoke mounting member 37.

[0038] 6, with rotor yoke 31 attached to outer end 24 by yoke attachment member 37, fan 40 is further attached to outer end 24 by fan attachment member 44. With fan 40 attached to outer end 24, cutout portion 47 prevents contact between yoke attachment member 37 and fan 40.

[0039] Because 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 remains attached, only the fan 40 can be removed from the outer end 24. In other words, it is possible to remove only the fan 40 from the outer end 24 of the rotor mounting member 20 while maintaining the rotor yoke 31 (rotor 30) attached to the outer end 24 of the rotor mounting member 20, thereby improving the maintainability of the outer rotor motor.

[0040] 5, fan 40 has fan body 41 and a plurality of blades 42 arranged in the circumferential direction. When fan 40 is attached to outer end 24, blades 42 of fan 40 are arranged in a space formed between fan body 41 and joint portion 38 curved by a plurality of curved portions 33, 36.

[0041] For example, if the joint 38 is configured so that the connecting portion 32 extends linearly in the vertical direction without providing a curved portion, 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 the same as that of the blades 42 in Fig. 1, the mounting position of the fan 40 shifts to the right in Fig. 1 along the axial direction of the motor shaft 10, and the cooling mechanism becomes larger.

[0042] By arranging the blades 42 in the space formed by bending the joint 38 by the multiple curved portions 33, 36, it is possible to further miniaturize the outer rotor motor 100 with a cooling mechanism that utilizes the rotational driving force of the motor. Furthermore, by bending the joint 38 by the multiple curved portions 33, 36, it is possible to expand the space in which the blades 42 can be arranged, as shown in Figure 1, and it becomes possible to cool the outer rotor motor 100 using a fan 40 that is smaller and has a larger blade 42 area and improved cooling performance.

[0043] [Second embodiment] FIG. 3 is a cross-sectional view showing the configuration of an outer rotor motor 100 according to a second embodiment. In the first embodiment, an example was described in which the fan 70 (external fan) and the fan 40 (internal fan) were arranged on one end of the motor shaft 10 as the cooling mechanism for the outer rotor motor 100. However, the present invention is not limited to this example. As shown in FIG. 3, it is also possible to arrange the fan 70 (external fan) on one end of the motor shaft 10 and the fan 40 (internal fan) on the other end of the motor shaft 10. In this case, the arrangement direction of the rotor mounting member 20 and the rotor 30 is opposite to that in FIG. 1, but the same effects as those of the outer rotor motor 100 according to the first embodiment can be obtained in this embodiment as well.

[0044] [Third embodiment] 4 is a cross-sectional view showing the configuration of an outer rotor motor 100 according to a third embodiment. In the first and second embodiments, an example configuration of an outer rotor motor 100 in which the rotor mounting member 20 is integrally formed with the motor shaft 10 by, for example, casting or machining has been described, but it is also possible to configure the rotor mounting member 20 and the motor shaft 10 as separate parts.

[0045] In this case, for example, as shown in FIG. 4, a tapered portion 11A is provided on the motor shaft 10, and an engagement hole 11B that engages with the tapered portion 11A is provided on the rotor mounting member 20, and the rotor mounting member 20 is positioned at a predetermined position on the motor shaft 10 using the tapered portion 11A and the engagement hole 11B.

[0046] In the example of Figure 4, fan 70 (external fan) is arranged on one end side of the motor shaft 10, and fan 40 (internal fan) is arranged on the other end side of the motor shaft 10. However, as shown in Figure 1, fan 70 (external fan) and fan 40 (internal fan) may also be arranged on one end side of the motor shaft 10, and in this embodiment as well, the same effects as those of the outer rotor motor 100 in the first embodiment can be obtained.

[0047] [Summary of the embodiment] Configuration 1. The outer rotor motor of the above embodiment is an outer rotor motor (e.g., 100 in FIG. 1) having a rotor (e.g., 30 in FIG. 1) in which a magnet (e.g., 35 in FIG. 1) is arranged on the inner circumferential surface of a cylindrical rotor yoke (e.g., 31 in FIG. 1), a motor shaft (e.g., 10 in FIG. 1) that rotatably supports the rotor (30); a rotor mounting member (e.g., 20 in FIG. 1) having a base end (e.g., 22 in FIG. 1) extending radially outward from the outer periphery of the motor shaft (10), and an outer end (e.g., 24 in FIG. 1) formed radially outward from the outer periphery of the base end (22), the outer end portion (24) is formed at a position closer to the inner peripheral surface of the rotor yoke (31) than to the outer peripheral surface of the motor shaft (10); The rotor (10) is attached to the outer end (24).

[0048] In the outer rotor motor of configuration 1, the outer end 24 to which the rotor 30 is attached is formed closer to the inner surface of the cylindrical rotor yoke 31 than to the outer surface of the motor shaft 10, thereby reducing the effect of centrifugal force (load) that may be generated by the rotation of the rotor 30, and making it possible to provide an outer rotor motor with excellent strength reliability.

[0049] Configuration 2. In the outer rotor motor of the above embodiment, the base end (22) is formed so that the axial thickness of the motor shaft (10) gradually decreases from the outer periphery of the motor shaft (10) toward the outer end (24) radially outward.

[0050] In the outer rotor motor of configuration 2, the rotor mounting member 20 has a base end 22 formed so that the thickness in the axial direction of the motor shaft gradually decreases toward the radially outer outer end, thereby ensuring the rigidity of the base portion of the outer end 24 to which the rotor 30 is mounted, while making it possible to distribute loads (stress concentrations) that may occur locally at the portion on the fixed end side of the base end 22 (the portion on the motor shaft 10 side) due to rotation of the rotor 30.

[0051] By forming the outer end portion radially outward from the outer periphery of the base end portion, which is formed to ensure rigidity and prevent stress concentration, it is possible to form the outer end portion closer to the inner periphery of the cylindrical rotor yoke than to the outer periphery of the motor shaft.This reduces the effects of centrifugal force (load) that may be generated by rotor rotation, making it possible to provide an outer rotor type motor with excellent strength reliability.

[0052] Configuration 3: In the outer rotor type motor of the above embodiment, a step portion (e.g., 26 in FIG. 2) is formed between the base end portion and the outer end portion along the axial direction of the motor shaft, The rotor (30) is attached to the outer end (24) with the opening of the rotor yoke (31) fitted into the step portion (26).

[0053] In the outer rotor motor of configuration 3, the rotor 30 (rotor yoke 31) and rotor mounting member 20 are easily positioned by using a spigot connection (connected by stepped fit) using a step, making it possible to reduce axial center errors during assembly. In addition, the spigot connection increases the contact area between the rotor yoke 31 and the outer end 24 and base end 22 of the rotor mounting member 20, making it possible to distribute the load acting on the outer end 24 to the base end 22 side when the rotor 30 is mounted.

[0054] Configuration 4: In the outer rotor motor of the above embodiment, the cylindrical rotor yoke (31) is a coupling portion (e.g., 32 in FIG. 1) formed to overlap the outer end portion along a vertical direction intersecting the axial direction of the motor shaft; a cylindrical portion (e.g., 34 in FIG. 1) formed so that the magnet can be arranged along the inner circumferential surface; A plurality of curved portions (e.g., 33, 36 in FIG. 1) are formed between the connecting portion (32) and the tubular portion (34), and a joining portion (e.g., 38 in FIG. 1) joins the connecting portion (32) and the tubular portion (34) via the plurality of curved portions (33, 36).

[0055] In the outer rotor motor of configuration 4, by providing multiple curved portions, the curved angle at each curved portion can be smoothly formed as an obtuse angle between the joint portion 32 and the tubular portion 34. This can further reduce stress concentration inside the rotor yoke 31 compared to when the joint portion 32 and the tubular portion 34 are bent at a right angle.

[0056] Configuration 5: The outer rotor motor of the above embodiment further includes a fan (e.g., 40 in FIG. 1) formed concentrically with the rotor yoke (31), The fan (40) is attached to the outer end (24) with the rotor yoke (31) attached between the fan (40) and the outer end (24).

[0057] Configuration 6: In the outer rotor motor of the above embodiment, the outer end (24) is concentrically formed with a first engagement portion (e.g., 29B in FIG. 8) that can engage with a yoke mounting member (e.g., 37 in FIGS. 7 and 8) for mounting the rotor yoke, and a second engagement portion (e.g., 29A in FIG. 8) that can engage with a fan mounting member (44) for mounting the fan (40).

[0058] According to the outer rotor motors of configurations 5 and 6, by attaching the rotor yoke 31 and the fan 40 concentrically to the outer end 24 of the rotor mounting member 20, there is no need to provide a separate fan mounting portion at the outer end 24 as a structure for mounting the fan 40, and it is possible to reduce the size of the outer end 24 (the radial dimension of the outer end 24).

[0059] Configuration 7: In the outer rotor motor of the above embodiment, the rotor yoke (31) is formed with a concentric through-hole (e.g., 39B in FIG. 7) through which the rotor mounting member (37) is inserted and a through-hole (e.g., 39A in FIG. 5) through which the fan mounting member (44) is inserted.

[0060] With the outer rotor motor of configuration 7, there is no need to consider restrictions on the cross-sectional shape or arrangement of the engagement portion for attaching fan 40 to rotor yoke 31 when designing the shape of rotor yoke 31. For example, when attaching fan 40 to rotor yoke 31, consideration must be given to engagement with fastening members, which may result in restrictions on shape design, such as having to form a linearly extending bottom portion of coupling portion 32 of rotor yoke 31.

[0061] By configuring the fan 40 to be attached to the outer end 24 of the rotor mounting member 20, it is possible to improve the degree of freedom in designing the shape of the rotor yoke 31. For example, as in the cross-sectional shape of the rotor yoke 31 shown in Figure 1, it is possible to form multiple curved portions 33, 36 between the joint portion 32 and the cylindrical portion 34. This allows the shape of the rotor yoke 31 to be designed in a way that alleviates stress concentration.

[0062] Configuration 8: In the outer rotor type motor of the above embodiment, the cylindrical rotor yoke (31) is a coupling portion (e.g., 32 in FIG. 1) formed to overlap the outer end portion along a vertical direction intersecting the axial direction of the motor shaft; a cylindrical portion (e.g., 34 in FIG. 1) formed so that the magnet can be arranged along the inner circumferential surface; a plurality of curved portions (e.g., 33 and 36 in FIG. 1) are formed between the connecting portion (32) and the tubular portion (34), and a joining portion (e.g., 38 in FIG. 1) is provided to join the connecting portion (32) and the tubular portion (34) via the plurality of curved portions (33 and 36); The blade portion (e.g., 42 in FIG. 1) of the fan (40) is disposed in the space formed between the joint portion (38) curved by the plurality of curved portions (33, 36) and the fan (40).

[0063] Configuration 9: In the outer rotor type motor of the above embodiment, the joint portion (38) has the following curved portions: a first curved portion (e.g., 36 in FIG. 1 ) formed between the connecting portion (32) formed in a direction perpendicular to the axial direction of the motor shaft (10) and the cylindrical portion (34) formed along the axial direction, the first curved portion being formed so as to curve the joint portion (38) toward the cylindrical portion at a first angle; and a second curved portion (e.g., 33 in FIG. 1) formed to bend at a second angle so as to join the joint portion (38), which is curved at the first angle by the first curved portion (36), to the tubular portion (34).

[0064] According to the outer rotor motors of configurations 8 and 9, by arranging the blade portion 42 in the space formed by the curved joint portion 38, it is possible to further miniaturize the outer rotor motor with a cooling mechanism (fan) that utilizes the rotational driving force of the motor.

[0065] Furthermore, by bending the joint 38 using multiple curved portions 33, 36, the space in which the blade portion 42 can be placed can be expanded, making it possible to cool the outer rotor motor 100 using a fan 40 that is smaller in size and has a larger blade portion 42 area, thereby improving cooling performance.

[0066] Configuration 10: In the outer rotor motor of the above embodiment, the fan (40) is formed with a notch (e.g., 47 in Figure 6) that is formed to avoid contact with the yoke mounting member (37) that mounts the rotor yoke (31) to the outer end (24).

[0067] According to the outer rotor motor of configuration 10, it is possible to remove only the fan 40 from the outer end 24 of the rotor mounting member 20 while maintaining the rotor yoke 31 (rotor 30) attached to the outer end 24 of the rotor mounting member 20, thereby improving the maintainability of the outer rotor motor.

[0068] Configuration 11. In the outer rotor type motor of the above embodiment, the outer end portion is When the distance from the center of the motor shaft to the radial center of the outer end portion is defined as a first distance, and the distance from the center of the motor shaft to the outer peripheral surface of the yoke is defined as a second distance, The sensor is attached at a position that satisfies the relationship of the first distance>0.5×the second distance.

[0069] According to the outer rotor motor of configuration 11, the outer end 24 to which the rotor 30 is attached is formed at a position closer to the inner surface of the cylindrical rotor yoke 31 than to the outer surface of the motor shaft 10 (first distance > 0.5 x second distance), thereby reducing the effect of centrifugal force (load) that may be generated by the rotation of the rotor 30, and making it possible to provide an outer rotor motor with excellent strength reliability.

[0070] The present invention is not limited to the above-described embodiments, and various modifications and variations can be made without departing from the spirit and scope of the present invention. Therefore, to apprise the public of the scope of the present invention, the following claims are appended. [Explanation of symbols]

[0071] 10: motor shaft, 11A: tapered portion, 11B: engagement hole, 20: rotor mounting member, 22: base end portion, 24: outer end portion, 30: rotor, 31: rotor yoke, 32: coupling portion, 33: curved portion (second curved portion), 34: cylindrical portion, 35:, 36: curved portion (first curved portion), 37: rotor mounting member, 38: joint portion, 39A: through hole, 39B: through hole, 40: fan, 41: fan body, 42: blade portion, 44: fan mounting member, 47: notch portion, 100: outer rotor type motor

Claims

[Claim 1] An outer rotor motor having a rotor in which magnets are arranged on the inner circumferential surface of a cylindrical rotor yoke, a motor shaft that rotatably supports the rotor; a rotor mounting member having a base end portion extending radially outward from an outer periphery of the motor shaft, and an outer end portion extending radially outward from the outer periphery of the base end portion; a first fan and a second fan are provided as a cooling mechanism using fans formed concentrically with the rotor yoke; The cylindrical rotor yoke is a coupling portion formed to overlap the outer end portion along a vertical direction intersecting an axial direction of the motor shaft; a cylindrical portion formed so that the magnet can be arranged along an inner circumferential surface thereof; a joining portion that joins the joining portion and the tubular portion via a plurality of curved portions formed between the joining portion and the tubular portion, the blades arranged in the circumferential direction of the first fan body are arranged in a space formed between the joint portion curved by the plurality of curved portions and the first fan body, The rotor and the first fan are attached to the outer end by a fan attachment member, and the second fan is attached to a position on the axial end side of the motor shaft that is different in the axial direction from the position of the base end that extends from the outer periphery of the motor shaft. An outer rotor motor characterized by:

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