WO2018235683A1

WO2018235683A1 - Brushless dc motor and ceiling fan using same

Info

Publication number: WO2018235683A1
Application number: PCT/JP2018/022496
Authority: WO
Inventors: 松本　敏宏
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2017-06-19
Filing date: 2018-06-13
Publication date: 2018-12-27

Abstract

A brushless DC motor (9) comprising a shaft (3), a stator core (1), a coil (2), a rotor holder (5), bearings (4a, 4b), an insert ring (5b), and a plurality of magnets (6). The shaft has an axis of rotation. The stator core is fixed to the shaft. The coil is provided in the stator core. The rotor holder has a holder outer shell (5a) made of aluminum and an inner circumferential surface (52) facing the stator core. The bearing includes inner rings (43, 45) through which the shaft penetrates and outer rings (44, 46) fixed to the rotor holder. The insert ring comprises a ferromagnetic metal, is provided on the inner circumferential surface of the rotor holder, and annularly covers the inner circumference of the holder outer shell, in the circumferential direction. The plurality of magnets are provided in the inner circumferential surface (54) of the insert ring.

Description

Brushless DC motor and ceiling fan using the same

The present invention relates to a blower having a brushless DC motor for driving a fan, such as a ceiling fan, mounted thereon.

In recent years, in a blower mounted on a ceiling fan or the like, high output and high efficiency are required. In the case of a blower mounted with a brushless DC motor, a motor having a high magnetic force magnet is required. In addition, noise reduction and vibration reduction are also required, and it is necessary to rotate the motor smoothly.

Heretofore, as this type of brushless DC motor, one having a configuration disclosed in Patent Document 1 is known. Hereinafter, the brushless DC motor will be described with reference to FIG. FIG. 11 is a longitudinal sectional view of a conventional brushless DC motor.

As shown in FIG. 11, the motor 101 mainly includes a stator portion 102 fixed to a device housing of a motor drive device (not shown) and a rotor portion 103 rotating around a predetermined central axis L.

The stator portion 102 includes a bracket 111, a stator core 112, a coil 113, and a slide bearing 114.

The stator core 112 has an annular core back 116 fitted on the radial outer peripheral surface (hereinafter simply referred to as the outer peripheral surface) of the holder portion 115 of the bracket 111, and a plurality of core backs 116 projecting radially outward from the core back 116. And a tooth portion 117 of the book.

The coil 113 is constituted by a conducting wire wound around each of the teeth portions 117 of the stator core 112.

The rolling bearing 114 is fixed to the inner peripheral surface of the holder portion 115 of the bracket 111 with an adhesive or the like at an interval in the axial direction and vertically.

The rotor portion 103 has a shaft 121, a rotor holder 120, and a rotor magnet 130.

The shaft 121 is a substantially cylindrical member disposed along the central axis L, and is inserted into the holder portion 115 of the bracket 111 of the stator portion 102 via the rolling bearing 114.

On the inner peripheral surface of the cylindrical portion 122 of the rotor holder 120, a plurality of rotor magnets 130 arranged at equal intervals in the circumferential direction around the central axis L are fixed by an adhesive or the like. The rotor holder 120 is formed of a metal material having the property of a ferromagnetic material such as a galvanized steel sheet.

Further, as shown in FIG. 11, the rotor magnet 130 is fixed to the cylindrical portion 122 of the rotor holder 120 so as to face the inner peripheral surface of the rotor magnet 130 and the tip of the stator core 112 via a minute gap in the radial direction. ing. Further, an adhesive layer 124 is formed on the inner peripheral surface of the cylindrical portion 122 of the rotor holder 120.

JP, 2010-98783, A

In a conventional brushless DC motor, a plurality of rotor magnets 130 are bonded to a rotor holder 120, that is, a rotor yoke. The rotor holder 120 is made of a galvanized steel plate or the like, which is a ferromagnetic body, because it functions as a yoke. Since the processing of the rotor holder 120 is performed by press molding, the roundness is bad, and in some cases, the rotor and the stator may come in contact with each other. Moreover, the flatness of the magnet affixing surface was bad and the subject that the adhesive force of the rotor magnet 130 was weak occurred.

Therefore, the present invention forms the inner peripheral surface of the rotor magnet with high accuracy, that is, manufactures the distance between the stator core and the magnet surface with high accuracy, and as a result, the brushless DC motor that rotates efficiently and this brushless DC motor. It aims at providing a blower.

A brushless DC motor according to an aspect of the present invention includes a shaft, a stator core, a coil, a rotor holder, a bearing, an insert ring, and a plurality of magnets. The shaft has a rotational axis. The stator core is fixed to the shaft. The coil is provided on the stator core. The rotor holder has an aluminum holder outer shell and an inner peripheral surface facing the stator core. The bearing includes an inner ring passing through the shaft and an outer ring fixed to the rotor holder. The insert ring is a ferromagnetic metal and is provided on the inner peripheral surface of the rotor holder and annularly covers the inner periphery of the outer shell of the holder in the circumferential direction. The plurality of magnets are provided on the inner circumferential surface of the insert ring.

According to one aspect of the invention, the rotor holder, whose outer shell is made of aluminum, comprises an insert ring between the outer shell and the magnet. As a result, the magnet mounting surface can be formed with high accuracy, and the accuracy of the distance between the internal magnet and the stator can be increased. Therefore, such a brushless DC motor can continue rotating efficiently.

FIG. 1 is an exploded perspective view of a brushless DC motor according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view of the same brushless DC motor. FIG. 3 is a perspective view showing a rotor holder of the brushless DC motor. FIG. 4 is an external view of a control circuit board of the brushless DC motor. FIG. 5 is an exploded perspective view of the position detection element of the brushless DC motor. FIG. 6 is a perspective view of the position detection element of the brushless DC motor. FIG. 7 is a schematic view of a stator core of the brushless DC motor. FIG. 8 is a connection diagram of windings of the brushless DC motor. FIG. 9 is an enlarged perspective view of a substrate holder supporting portion of the brushless DC motor. FIG. 10 is an external view of a ceiling fan using the same brushless DC motor. FIG. 11 is a longitudinal sectional view of a conventional brushless DC motor.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following embodiment is an example embodying the present invention, and does not limit the technical scope of the present invention. Moreover, the same code | symbol is attached | subjected about an identical site | part through all the drawings, and the description after the second time is abbreviate | omitted. Furthermore, in the drawings, the description of the details of each part not directly related to the present invention is omitted.

First Embodiment
First, a schematic configuration of a brushless DC motor 9 according to a first embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is an exploded perspective view of the brushless DC motor 9.

As shown in FIGS. 1 and 2, the brushless DC motor 9 includes a stator core 1, a rotor holder 5, and a rotor cover 8. The magnet 6 is attached to the rotor holder 5. The rotor holder 5 and the rotor cover 8 integrally constitute a rotor.

The stator core 1 includes a plurality of teeth portions 1 a radially disposed around the shaft 3 and has a disk shape as a whole. A shaft 3 is fixed to a central portion of the stator core 1 in a penetrating manner. The drive coil 2 is wound around each tooth portion 1a of the stator core 1 via a resin film (slot insulator). By energizing the drive coil 2, a magnetic field is generated. The thickness of the stator core 1 is a matter of design and can be various thicknesses. Therefore, the stator core 1 has a cylindrical shape in some cases.

An inner ring 43 of a bearing 4 a (first bearing) is rotatably disposed relative to the shaft 3 at an upper side (upper side in FIG. 1) of the shaft 3 in the rotational axis direction. In the shaft 3, the inner ring 45 of the bearing 4 b (second bearing) can be rotated relative to the shaft 3 at the lower side (lower side in FIG. 1) of the rotation axis opposite to the bearing 4 a with the stator core 1 interposed therebetween. Is located in

At the outer peripheral end 1 c of the stator core 1, a position detection element unit 7 for detecting the magnetic flux of the magnet 6 provided on the inner peripheral surface of the rotor holder 5 is fixed.

The rotor holder 5 has a bowl-like shape, and more specifically, a cylindrical shape having a top surface 51 and an inner peripheral surface 52 connected to the top surface 51. The top surface 51 of the rotor holder 5 is provided at its central portion with a shaft opening 53 (see FIG. 2) through which the shaft 3 passes. The diameter of the cylinder decreases on the way from the bottom surface of the rotor holder 5 to the top surface 51, whereby the step 14a and the step 14b are formed. A plurality of magnets 6 are attached to the inner circumferential surface 52 of the rotor holder 5 at predetermined intervals in the circumferential direction of the cylindrical side surface. The rotor holder 5 accommodates the stator core 1 in a space defined by the top surface 51 and the inner circumferential surface 52.

The bottom surface of the rotor holder 5 is an opening. The rotor cover 8 covers the opening of the bottom surface of the rotor holder 5. Thereby, as the brushless DC motor 9, the space inside the rotor holder 5 is closed. The rotor cover 8 has a substantially circular shape that is larger than the opening of the bottom surface of the rotor holder 5, and is provided with a shaft opening 8 a through which the shaft 3 penetrates at the center. The rotor cover 8 may be detachably attached to the rotor holder 5 by, for example, a screw, a bolt and a nut, an elastically deformable claw or the like.

As described above, the brushless DC motor 9 is an outer rotor type in which the rotor having the rotor holder 5 and the rotor cover 8 integrated with the outer periphery of the stator core 1 fixed to the shaft 3 rotates.

The outer ring 44 of the bearing 4 a is fixed to the rotor holder 5 when assembling the stator core 1, the rotor holder 5, and the rotor cover 8 having the above configuration. The outer ring 46 of the bearing 4 b is fixed to the rotor cover 8. In this state, the upper portion of the shaft 3 penetrates the shaft opening 53 of the rotor holder 5, and the lower portion of the shaft 3 penetrates the shaft opening 8 a of the rotor cover 8. The magnet 6 disposed on the inner circumferential surface 52 of the rotor holder 5 faces the outer peripheral curved surface of the teeth portion 1 a constituting the stator core 1, that is, the opposing surface. That is, the brushless DC motor 9 is configured such that the rotor holder 5 and the rotor cover 8 wrap the stator core 1.

In the brushless DC motor 9, the rotor holder 5 and the rotor cover 8 are integrally driven to rotate around the shaft 3 as a central axis by supplying a controlled current to the drive coil 2. In addition, since the control method of an electric current is not directly related to this invention, it abbreviate | omits details.

The connection between the shaft 3 and the stator core 1 and the rotor holder 5 in the present embodiment will be described in detail.

The shaft 3 has a hollow cylindrical shape, and internally has a power supply line for supplying power and a control line for controlling rotation. The shaft 3 has a step 3a (first step) with which the inner ring 43 of the bearing 4a abuts on the upper side in the rotational axis direction (the upper side in FIG. 1). The step 3 a is annularly formed on the outer periphery of the shaft 3. The outer diameter of the shaft 3 is larger at the lower side in the rotational axis direction than at the upper side in the rotational axis direction of the step 3a. The outer diameter of the shaft 3 in the rotational axis direction above the step 3 a is smaller than the inner diameter of the inner ring 43 so as to be smoothly inserted into the inner ring 43 of the bearing 4 a.

Further, a step 3 b (second step) is provided on the lower side in the rotation axis direction of the shaft 3. The step 3 b is annularly formed on the outer periphery of the shaft 3. The outer diameter of the shaft 3 is smaller at the lower side in the rotational axis direction than at the upper side in the rotational axis direction of the step 3 b. That is, the outer diameter (third outer diameter) of the portion between the step 3a and the step 3b is the outer diameter (first outer diameter) of the step 3a above the rotational axis and the lower side of the step 3b in the rotational axis Is larger than the outer diameter (second outer diameter) of The outer diameter of the shaft 3 below the step 3 b in the rotational axis direction is smaller than the inner diameter of the inner ring 45 so as to be smoothly inserted into the inner ring 45 of the bearing 4 b. Thus, the shaft 3 has the large diameter portion 36 (third section) between the step 3a and the step 3b. The shaft 3 further has a small diameter portion 34 (first section) above the step 3 a and a small diameter portion 35 (second section) below the step 3 b. Further, the outer diameter of the large diameter portion 36 of the shaft 3 is larger than the inner diameter of the inner ring 43 of the bearing 4a and larger than the inner diameter of the inner ring 45 of the bearing 4b.

The stator core 1 is press-fitted and fixed to the large diameter portion 36 of the shaft 3.

The bearing 4 a is inserted from above in the rotational axis direction of the shaft 3. The inner ring 43 of the bearing 4a is held in contact with the step 3a. The shaft 3 is passed through the shaft opening 53 of the rotor holder 5. The outer ring 44 of the bearing 4 a is press-fit into the bearing holding portion 13 provided around the shaft opening 53 of the rotor holder 5.

A control circuit board 10 is provided below the stator core 1 in the rotational axis direction. The control circuit board 10 is electrically and physically connected to the stator core 1 to control driving of the brushless DC motor 9. The control circuit board 10 is composed of a substrate holder 10a and a substrate 10b. The substrate holder 10a has a cylindrical portion 10c at the center portion through which the shaft 3 passes. The substrate 10 b is provided with an opening through the cylindrical portion 10 c and the shaft 3 at the center. In the present embodiment, the opening provided at the central portion of the substrate 10b communicates with the outer periphery of the substrate 10b, and has a so-called notch shape. Furthermore, the substrate holder 10a has holding portions 10d for the inner circumference and the outer circumference for holding the substrate 10b. The inner peripheral holding portion 10d holds the inner peripheral side of the substrate 10b. The outer peripheral holding portion 10d holds the outer peripheral side of the substrate 10b. The holding portion 10d for the outer periphery is composed of an arm portion 10e protruding in the radial direction and a claw portion 10f for holding the substrate 10b mounted from below in the rotation axis direction. The holding portion 10d for the inner circumference comprises an arm portion 10e extending downward in the rotation axis direction and a claw portion 10f for hooking and holding the substrate 10b mounted from below the rotation axis direction.

As shown in FIG. 4, the substrate 10 b has an opening (hereinafter, central opening) 37 through which the shaft 3 passes in a substantially central portion. The central opening 37 communicates with the outer periphery, and the outer shape of the substrate 10 b is a shape like “C” of the alphabet. As shown in FIG. 2, the substrate holder 10a holds the outer periphery of the substrate 10b with the outer peripheral holding portion 10d (the claws 10f), and the central opening 37 of the substrate 10b is the inner peripheral holding portion 10d (the claws 10f). Hold with). More specifically, the engagement of the claws 10f of the inner peripheral holding portion 10d is on the outer peripheral side of the central opening of the substrate 10b than the portion through which the shaft 3 penetrates, and the central portion and the outer peripheral portion It is a communication part which connects

A substrate holder support 18 is provided in the stator core 1. The substrate holder support portion 18 has a plurality of cylindrical walls erected downward in the radial direction outer side of the shaft 3 and in the radial direction inner side of the drive coil 2 on the lower side of the stator core 1, that is, the substrate holder 10a side. . The substrate holder support 18 is molded using a resin.

The shaft 3 is inserted into the substrate holder 10a, and at the fixed position, the cylindrical portion 10c is in contact with the stator core 1 at the upper end side in the rotation axis direction. That is, the cylindrical portion 10 c has an upper end 10 g (third end) that abuts on the stator core 1. The substrate holder 10 a is in contact with the lower end of the substrate holder support 18.

Furthermore, in a state where the substrate 10 b is mounted, the elastic member 11 is inserted into the shaft 3 from the lower side in the rotation axis direction. The inner diameter of the elastic member 11 is slightly larger than the outer diameter of the shaft 3. More specifically, the inner diameter of the elastic member 11 is larger than the outer diameter of the large diameter portion 36 of the shaft 3. Then, the upper end 11a (first end) of the elastic member 11 in the rotation axis direction abuts on the lower end 10h (fourth end) of the cylindrical portion 10c of the substrate holder 10a. The elastic force of the elastic member 11 is applied to the stator core 1 via the substrate holder 10a on the upper end 11a side. In the present embodiment, the elastic member 11 is a spring, and a wave washer, a rubber washer, a urethane (rubber) sleeve or the like may be used.

The bearing 4 b is inserted near the lower end or lower end of the shaft 3. That is, the bearing 4 b is located at the small diameter portion 35 of the shaft 3. The lower end 11 b (second end) of the elastic member 11 is in contact with the inner ring 45 of the bearing 4 b. The elastic force of the elastic member 11 is applied to the inner ring 45 of the bearing 4b on the lower end 11b side. The bearing 4 b is press-fitted and fixed to the bearing mounting portion 8 b of the rotor cover 8. More specifically, the outer ring 46 of the bearing 4b is press-fitted and fixed to the bearing mounting portion 8b of the rotor cover 8, and the inner ring 45 is not in contact.

With such a configuration, the control circuit board 10 is pressurized and fixed between the bearing 4 b and the stator core 1 by the elastic member 11. The elastic member 11 presses the inner ring 45 of the bearing 4 b to cause a shift in the rotational axis direction between the inner ring 45 and the outer ring 46 of the bearing 4 b. That is, the inner ring 45 of the bearing 4 b is positioned below the outer ring 46 in the rotation axis direction. On the other hand, the pressing force of the elastic member 11 in contact with the substrate holder 10a is applied to the inner ring of the bearing 4a via the substrate holder 10a, the stator core 1 and the shaft 3 at the upper side in the rotational axis direction. Further, the downward pressure of the elastic member 11 pushes the bearing 4 b downward, and pushes the rotor cover 8 and the rotor holder 5 fixed thereto downward. In response to this, it can be said that the rotor holder 5 pushes the outer ring 44 of the bearing 4a downward. That is, the inner ring 43 of the bearing 4 a is positioned above the outer ring 44 in the rotational axis direction.

As described above, the control circuit board 10 is in a state of being pushed toward the stator core 1 integrated with the shaft 3 by the elastic member 11 and held. Therefore, the rotor cover 8 can be removed downward by disassembling the rotor holder 5 and the rotor cover 8. Since the bearing 4 b is not fixed to the shaft 3 but fixed to the rotor cover 8, the bearing 4 b is removed together with the rotor cover 8. The elastic member 11 is only inserted into the shaft 3 and not fixed to the shaft 3. The elastic member 11 can also be easily removed downward. By removing the elastic member 11, the upward pressure of the control circuit board 10 by the elastic member 11 is released. The control circuit board 10 can be removed downward by releasing the upward pressure. Thus, the stator core 1 integrated with the shaft 3 and the control circuit board 10 can be easily disassembled. The outer diameter of the small diameter portion 34 of the shaft 3 is smaller than the inner diameter of the inner ring 43 of the bearing 4a. The outer diameter of the small diameter portion 35 of the shaft 3 is smaller than the inner diameter of the inner ring 45 of the bearing 4b. Therefore, the bearing 4 a and the bearing 4 b can be easily removed from the shaft 3.

Further, since the length of the shaft 3 and the length of the cylindrical portion 10c in the rotational axis direction can be adjusted at the design stage, the stroke of the elastic member 11 can be appropriately secured. That is, the magnitude of the pressurization by the elastic member 11 can be set appropriately. By appropriately applying pressure to the

bearings

4a and 4b, the heat generation from the

bearings

4a and 4b is suppressed, and the noise generated from the

bearings

4a and 4b is reduced, resulting in the

bearings

4a and 4b. Can be suppressed.

Next, the rotor holder 5 and the attachment of the magnet 6 to the rotor holder 5 will be described.

As shown in FIG. 3, the rotor holder 5 is provided with a fixing portion 12 for attaching the rotor cover 8 to the bottom. The fixing portion 12 protrudes outward at the bottom of the rotor holder 5 and has a screw hole for fixing through a screw. The fixing portion 12 may have a flange shape integrally formed in the circumferential direction, or may have a shape in which only a screw hole portion is extended as shown in FIG. 3.

Further, the rotor holder 5 has a holder outer shell 5a made of aluminum and an insert ring 5b provided on the inner peripheral side thereof. As described above, the holder outer shell 5 a of the rotor holder 5 has a substantially cylindrical shape, and the top is the top surface 51 having the shaft opening 53 and the bottom is the opening closed by the rotor cover 8. In the cylindrical portion of the holder outer shell 5a, ring-shaped steps are provided at two positions so as to decrease in diameter toward the top, that is, the top surface 51 (step 14a, step 14b). The step 14a is provided below the step 14b. A balance weight insertion hole 41 into which the balance weight 40 is inserted is annularly provided on the bottom side of the step 14a. The bearing holding portion 13 is provided on the top surface 51 above the step 14 b.

As shown in FIGS. 2 and 3, the insert ring 5 b is provided on the inner peripheral surface of the holder outer shell 5 a so as to cover the region between the step 14 a and the step 14 b. The upper surface of the insert ring 5b is provided to abut on the step 14b. Then, the magnet 6 is mounted on the inner circumferential surface 54 of the insert ring 5 b. The magnet 6 is mounted such that the upper surface of the magnet 6 abuts on the step 14 b. The insert ring 5b is a flat plate made of a ferromagnetic metal and made cylindrical according to the inner peripheral surface of the holder outer shell 5a and mounted on the holder outer shell 5a. Iron etc. are mentioned as a metal of the ferromagnetic which forms the insert ring 5b.

The holder outer shell 5a is made of aluminum die cast. According to the die casting method, the outer shape of the holder outer shell 5a can be designed with a high degree of freedom. The inner peripheral surface 54 of the insert ring 5b can be made into a cylindrical shape with high accuracy by performing cutting with a lathe or the like after the insert ring 5b is attached. That is, the inner peripheral surface 54 of the insert ring 5b is a cylinder whose section is close to a perfect circle. The magnet 6 is adhesively fixed to the inner circumferential surface 54 of the insert ring 5b. Therefore, the magnet 6 mounted on the inner circumference of the cylinder close to a perfect circle is accurately disposed relative to the shaft 3. That is, the distance between the outer peripheral surface of the stator core 1 and the magnet 6 becomes accurate, and the brushless DC motor 9 rotates efficiently.

Moreover, the flatness (surface smoothness) of the surface to which the magnet 6 is adhered can be raised by cutting, and the adhesive force of the magnet can be improved. Furthermore, by bringing a solid metal only to the surface to which the magnet 6 is adhered by cutting on the surface, the adhesion of the magnet can be improved, and rusting can be suppressed without cutting other than the surface to be adhered.

Further, the insert ring 5b may be formed by rounding a rectangular metal flat plate with three rolls. And when forming a cylinder, the part which joins the ends of a flat plate, ie, a joint, is made. At this joint, it becomes difficult to pass the magnetic flux. Therefore, it is better that the end of the magnet 6 from which the magnetic lines of force originate and the joint of the insert ring 5b not coincide with each other. More preferably, the magnet 6 may be disposed so that the center of the magnet 6 and the joint of the insert ring 5b coincide with each other. In addition, since there are a plurality of magnets 6, the center in the circumferential direction of at least one of the plurality of magnets 6 may be coincident with the joint of the insert ring 5b. The joint is the circumferential end of the rounded metal flat.

Moreover, since the upper surface of the magnet 6 abuts on the step 14 b, positioning of the magnet 6 can be facilitated.

The thickness of the insert ring 5b, that is, the thickness in the radial direction, should be increased. That is, since the insert ring 5b functions as a rotor yoke, the thickness can be increased to alleviate the saturation of the magnetic flux. That is, by increasing the thickness of the insert ring 5b, the induced voltage generated in the winding can be increased, and the function of the magnet 6 can be sufficiently exhibited to provide the brushless DC motor 9 with high efficiency. The larger the thickness of the insert ring 5b, the higher the induced voltage generated. However, the induced voltage is saturated in a region of a predetermined thickness or more. Therefore, it is preferable to use an appropriate thickness of the insert ring 5b according to the magnetic force of the magnet 6 to be used.

Further, the length of the insert ring 5b in the rotation axis direction may be larger than the length of the magnet 6 in the rotation axis direction. By making the insert ring 5 b larger than the magnet 6, it is possible to efficiently pass the magnetic flux, and it becomes an efficient brushless DC motor 9.

Next, the position detection element unit 7 will be described.

As shown in FIG. 1, the stator core 1 is provided with an opening for arranging a winding after mounting a slot insulator, that is, a slot 1 b. A plurality of slots 1 b are provided in the circumferential direction. On the other hand, as described above, the control circuit board 10 for driving the brushless DC motor 9 is provided on the lower side in the rotation axis direction of the stator core 1. The position detection element unit 7 is provided to connect the control circuit board 10 and the outer peripheral end 1 c of the stator core 1.

Explaining in detail, as shown in FIG. 5 and FIG. 6, the position detection element unit 7 has a Hall element 7a that actually detects the position, and an element holder 7b that holds the Hall element 7a.

The Hall element 7 a is fixed to the control circuit board 10 and connected to a circuit formed on the control circuit board 10. Then, the Hall element 7a transmits the detected position to the control circuit. On the other hand, the element holder 7 b holding the Hall element 7 a has a projection 7 c protruding toward the stator core 1. The protrusion 7 c is inserted into the slot 1 b of the stator core 1 from below in the rotation axis direction. That is, the Hall element 7 a is positioned with respect to the stator core 1.

More specifically, the Hall element 7 a is provided upright on the control circuit board 10. The position where the hall element 7 a stands is a position substantially facing the outer peripheral end 1 c of the stator core 1. That is, the Hall element 7a is located in the vicinity of the outer peripheral end 1c of the stator core 1 in the radial direction. Hall element 7a is located in the lower part of stator core 1 in the rotation axis direction. More specifically, the Hall element 7a is located between the stator core 1 and the substrate 10b in the rotational axis direction. The vicinity of the outer peripheral end 1c where the hall element 7a is erected may be projected radially outward or inwardly with respect to the outer peripheral end 1c of the stator core 1, but the magnetic force of the magnet 6 is detected to It should be a position that does not become an obstacle to the rotation of

The element holder 7 b holds the three Hall elements 7 a integrally from the stator core 1 side. In this state, the projection 7 c is inserted into the slot 1 b so as to unite the control circuit board 10 with the stator core 1. A plurality of projections 7c are provided, and by being inserted into different slots 1b, positioning and fixation are reliably performed.

The length of the magnet 6 in the rotational axis direction is larger than the thickness of the stator core 1 in the rotational axis direction. The magnet 6 has a portion not facing the stator core 1 below the magnet 6. In particular, the magnet 6 protrudes toward the control circuit board 10 in the rotational axis direction with respect to the stator core 1. The Hall element 7a detects the magnetic force emerging from this portion.

According to such a configuration, the positional relationship between the drive coil 2 and the Hall element 7a is fixed regardless of the manufacturing process or the variation of parts. Therefore, the positional information of the rotor (magnet 6) output from the Hall element 7a can ensure high accuracy, and as a result, efficient motor characteristics can be obtained.

As shown in FIGS. 7 and 8, the brushless DC motor 9 according to the present embodiment has three-phase windings, that is, a winding U15, a winding V16, and a winding W17. And brushless DC motor 9 of this embodiment has 12 teeth part 1a. As shown in FIG. 7, twelve teeth portions 1 a are radially disposed about the shaft 3. The winding U15 includes a coil U15-1, a coil U15-2, a coil U15-3, and a coil U15-4 wound respectively around four U-phase teeth portions 1a. As shown in FIG. 7, the coil U15-1 and the coil U15-3 face each other across the rotation axis (shaft 3), and the coil U15-2 and the coil U15-4 face each other across the rotation axis. There is. The same applies to the V- and W-phase windings V16 and W17.

As shown in FIG. 8, the winding U15, the winding V16, and the winding W17 are connected by star connection. The coil U15-4, the coil V16-4 and the coil W17-4 are connected to the common.

For example, the winding U15 is wound continuously in the order of the coil U15-1, the coil U15-2, the coil U15-3, and the coil U15-4. That is, the winding U15 is made of a wire having a first end 15-8 and a second end 15-9. The electric wire forms a coil U15-1, a coil U15-2, a coil U15-3, and a coil U15-4. The electric wire further includes a connecting wire 24-1 connecting the coil U15-1 and the coil U15-2, a connecting wire 24-2 connecting the coil U15-2 and the coil U15-3, a coil U15-3 and a coil U15. A crossover line 24-3 is formed to connect with -4. Winding V16 likewise consists of a wire having a first end 16-8 and a second end 16-9. The electric wire forms a coil V16-1, a coil V16-2, a coil V16-3, a coil V16-4 and a connecting wire 22-1, a connecting wire 22-2, and a connecting wire 22-3. Winding W17 likewise consists of a wire having a first end 17-8 and a second end 17-9. This electric wire forms a coil W17-1, a coil W17-2, a coil W17-3, a coil W17-4 and a connecting wire 23-1, a connecting wire 23-2, and a connecting wire 23-3.

In the present embodiment, the connecting wires 24-2, 22-2, 23-2 of the windings U15, V16, W17 are processed using the substrate holder support portion 18.

The substrate holder support portion 18 includes a plurality of cylindrical walls erected between the shaft 3 and the winding U15, the winding V16, and the winding W17 as described above. As shown in FIG. 9, in the present embodiment, the substrate holder support 18 includes three cylindrical walls coaxially disposed, and the first support wall 18 a, the second support wall from the inner peripheral side 18b, the third support wall 18c. The heights of the first support wall 18a and the second support wall 18b are the same, and the substrate holder 10a abuts on the top thereof. On the other hand, the third support wall 18c has a lower height than the first support wall 18a and the second support wall 18b. The first support wall 18a and the second support wall 18b are provided with several recessed portions (portions with low wall heights) for passing a terminal wire and a common wire described later. The third support wall 18c has three levels of height in order to pass the crossover.

Between the first support wall 18a and the second support wall 18b, the winding U15, the winding V16, the first end 15-8, 16-8, 17-8 of the winding W17 and the second end An inner circumferential groove 19 is formed to pass 15-9, 16-9 and 17-9. An outer peripheral groove 20 is formed between the second support wall 18b and the third support wall 18c, through which the winding wires U15, winding V16, and crossover wires 24-2, 22-2 and 23-2 of winding W17 pass. It is done. That is, the substrate holder support 18 functions as a member for forming the inner circumferential groove 19 and the outer circumferential groove 20.

The winding (terminal wire) drawn from the coil U15-1, the coil V16-1, and the coil W17-1 is drawn into the inner circumferential groove 19 through the recess provided in the second support wall 18b. The connection process between the terminal wires and the lead wires is performed in the inner circumferential groove 19 and in the connection holes 21. That is, the first end 15-8 of winding U15, the first end 16-8 of winding V16, and the first end 17-8 of winding W17 are accommodated in inner circumferential groove 19. . The lead wire is taken out to the outside.

The connection hole 21 is provided on the inner peripheral side of the first support wall 18 a and protrudes inward. The lead wire and the terminal wire are soldered together to form a connection portion. The connection portion is held by being inserted into the connection hole 21.

On the other hand, the coil U15-4, the coil V16-4, and the winding (common wire of star connection) drawn out from the coil W17-4 also pass through the recess provided in the second support wall 18b, and the inside of the inner circumferential groove 19 Drawn out. Then, solder connection processing is performed in the inner circumferential groove 19. That is, second end 15-9 of winding U15, second end 16-9 of winding V16, and second end 17-9 of winding W17 are accommodated in inner circumferential groove 19. . In addition, the recessed part which lets a common wire pass is provided separately from the recessed part which lets a terminal wire pass.

The connecting wire 24-1 between the adjacent coil U15-1 and the coil U15-2 is laid in the winding space. The crossovers 24-3 between the adjacent coils U15-3 and U15-4 are also wound in the winding space. As described above, the coil U15-1 and the coil U15-3 face each other with the rotation axis interposed therebetween, and the coil U15-2 and the coil U15-4 face each other with the rotation axis interposed therebetween. The connecting wire 24-2 between the substantially opposing coil U15-2 and the coil U15-3 is laid in the outer peripheral groove 20 of the substrate holder support portion 18 so as not to be in contact with other windings. That is, the connecting wire 24-2 connected to the coil U15-2 is connected to the coil U15-3 at a substantially opposite position through the outer peripheral groove 20. Similarly, the connecting wire 22-2 between the coil V16-2 and the coil V16-3 and the connecting wire 23-2 between the coil W17-2 and the coil W17-3 pass through the outer peripheral groove 20. As mentioned above, the third support wall 18c has three levels of height. The walls having different heights are referred to as wall 18c-1, wall 18c-2 and wall 18c-3 in descending order. The terminal line and the common line are led to the inner circumferential groove 19 via the top of the wall 18c-1. The crossover wires 22-2, 23-2, and 24-2 are led to the outer peripheral groove 20 via the tops of the wall 18c-2 and the wall 18c-3. At that time, the crossovers 22-2, 23-2, and 24-2 pass through the tops of the third support walls 18c of different heights so that the winding U15, the winding V16, and the winding W17 do not contact. It is led into the outer circumferential groove 20.

As described above, the processing (arrangement) of the crossovers 22-2, 23-2, and 24-2 is performed using the outer peripheral groove 20 provided in the substrate holder support portion 18. As a result, the winding can be performed continuously, and the wiring can be simplified. That is, the winding operation is facilitated.

Further, the wiring process of the terminal line and the common line is performed in the inner circumferential groove 19. Wiring processing of the crossovers is performed in the outer peripheral groove 20. The inner circumferential groove 19 and the outer circumferential groove 20 are at different positions in the radial direction. As a result, the space in the radial direction can be effectively used without using the space in the rotational axis direction, and hence the size of the brushless DC motor 9 can be reduced. Further, by using the inner circumferential groove 19 and the outer circumferential groove 20, high insulation reliability can be exhibited.

Further, the connection portion between the terminal wire of the winding U15, the winding V16, and the winding W17 and the lead wire taken out to the outside is inserted into the connection hole 21. Thus, the connection portion between the terminal wire and the lead wire can be protected, and the insulation process using the insulation tube can be made unnecessary.

Further, the control circuit board 10 can be stably held by the tops of the first support wall 18 a and the second support wall 18 b being in contact with the substrate holder 10 a. The first support wall 18a and the second support wall 18b are disposed near the winding U15, the winding V16, and the winding W17, and have a cylindrical shape with a predetermined diameter. Therefore, the substrate holder 10a can be held more stably.

Further, as shown in FIG. 4, the ground portion 31 is printed on the substrate 10 b. One end 31 a of the ground portion 31 is provided at a predetermined position (referred to as a proximity portion 32 a) of the power supply line 32 with a distance of the discharge gap 33 being separated. The power supply line 32 is an input unit to which a power supply is connected, and in the present embodiment, an AC power supply is connected. In the present embodiment, an electric motor connected to a single-phase AC power supply is described as an example, and therefore, two power supply lines 32 are provided. In the proximity portions 32a of the respective power supply lines 32, the ground portions 31 are provided in proximity to each other. That is, power supply line 32 has proximity portion 32 a closest to ground portion 31. The shortest distance between the proximity portion 32 a of the power supply line 32 and the ground portion 31 corresponds to the discharge gap 33. The other end 31 b of the ground portion 31 is provided at an edge (around the central opening) of the central opening 37 of the substrate 10 b, particularly at a portion in contact with the shaft 3. The shaft 3 is in contact with the edge of the central opening 37 of the substrate 10b. Here, the edge of the central opening 37 of the shaft 3 and the substrate 10b is not always in contact with each other, and may have a narrow gap. That is, the inner diameter of the central opening 37 provided in the substrate 10 b is larger than the outer diameter of the shaft 3.

In such a configuration, when a high voltage such as a lightning surge is applied to the power supply line 32, a discharge occurs first across the discharge gap 33, and a large current flows in the ground portion 31. The current flowing to the ground portion 31 discharges and flows to the shaft 3 side at the other end 31 b of the ground portion 31, that is, the edge of the central opening 37 of the substrate 10 b. Then, the current escapes to the ground (GND) through the shaft 3, and as a result, the substrate 10b can be protected.

Thus, measures such as lightning surge can be made with a simple configuration without connecting the substrate 10b and the shaft 3 using lead wires.

The discharge gap 33 may be 0.5 mm or more.

The ground portion 31 may be printed so as to wrap around the inner peripheral surface of the central opening 37 from the edge of the central opening 37 of the substrate 10 b. That is, the other end 31 b of the ground portion 31 may be printed on the inner peripheral side end face of the central opening 37 of the substrate 10 b.

Such an outer rotor type brushless DC motor 9 is suitable for a ceiling fan having a large blade diameter. A ceiling fan is a blower provided so as to be suspended from a ceiling. In such a ceiling fan, it is necessary to adjust the imbalance of the balance caused by the large blade diameter. Specifically, when the blade is attached, adjustment is performed by arranging a balance weight at any position of the housing so that the center of gravity in the horizontal direction is on the rotation axis (shaft 3).

As shown in FIG. 3, in the present embodiment, a plurality of balance weight insertion holes 41 for mounting the balance weight 40 are provided on the bottom surface side of the holder outer shell 5 a. As shown in FIGS. 2 and 3, the balance weight insertion hole 41 is a hole through which the balance weight can be inserted from the bottom surface side of the holder outer shell 5a. And, a plurality of balance weight insertion holes 41 are provided at the bottom of the holder outer shell 5a and arranged in the circumferential direction. In the present embodiment, the bottom of the holder outer shell 5a is lined up with almost no gap. When adjusting the balance, one or more balance weights 40 are inserted into the balance weight insertion holes 41 so that the center of gravity in the horizontal direction is on the shaft 3.

In addition, the balance weight 40 may be reduced so that the balance can be finely adjusted. However, if the balance weight 40 is too small, there is a possibility that the ability to achieve the desired balance adjustment may be insufficient. Also, if the balance weight 40 is too large, balance adjustment becomes difficult.

The balance weight 40 in the present embodiment is a substantially rectangular plate. The balance weight insertion hole 41 holds the two opposing sides of the balance weight 40 so as to be sandwiched by two rails. The balance weight insertion hole 41 has a tapered shape, that is, a shape in which the back side is narrower than the inlet side. That is, the two rails forming the balance weight insertion hole 41 are not parallel but narrow from the entrance side to the back.

The balance weight insertion hole 41 is not limited to the above-described shape formed by two rails, and may be conical or pyramidal.

In the ceiling fan 50 using such an outer rotor type brushless DC motor 9, as shown in FIG. 10, the upper portion of the brushless DC motor 9 may be covered with a canopy 42. By using the canopy 42, the connection of the power supply wiring provided on the shaft 3 and the connection of the control wiring can be made inside the canopy 42. That is, the connection part of the power supply wiring and the connection part of the control wiring can be hidden.

Further, in the brushless DC motor 9 of the present embodiment, the control circuit board 10 is disposed below the stator core 1. As shown in FIG. 1, the control circuit board 10 of the brushless DC motor 9 has a large number of control parts mounted thereon for direct current driving. Therefore, by covering the stator core 1 side with the canopy 42, the canopy 42 and the ceiling fan 50 can be miniaturized.

The air blower mounted with the brushless DC motor according to the present invention is useful as a air blower mounted with a brushless DC motor for driving a fan, which is used for a ceiling fan with a large blade diameter or the like.

1 Stator core 1a Teeth portion 1b Slot 1c Outer peripheral end 2 Drive coil 3 Shaft 3a Step difference (first step)
3b Step (second step)
4a bearing (first bearing)
4b bearing (second bearing)
Reference Signs List 5 rotor holder 5a holder outer shell 5b insert ring 6 magnet 7 position detection element

7a hall element

7b element holder 7c projection 8 rotor cover 8a shaft opening 8b bearing mounting portion 9 motor 10 control circuit board 10a substrate holder 10b substrate 10c cylindrical portion

10d holding Part

10e Arm part

10f Claw part 10g Upper end (third end)
10h lower end (4th end)
11 elastic member 11a upper end (first end)
11b lower end (second end)
12 fixed part 13 bearing holding part

14a level difference

14b level difference 15 winding U
15-1, 15-2, 15-3, 15-4 Coil U
16 winding V
16-1, 16-2, 16-3, 16-4 Coil V
17 winding W
17-1, 17-2, 17-3, 17-4 Coil W
18 substrate holder support portion

18a support wall

18b support wall

18c support wall 19 inner circumferential groove 20 outer circumferential groove 21 connection hole 22-1, 22-2, 22-3 crossover 23-1, 23-2, 23-3 crossover 24-1, 24-2, 24-3 crossover 31 ground section 32 power supply line 33 discharge gap 34 small diameter section (first section)
35 Small diameter section (second section)
36 large diameter section (third section)
41 Balance weight insertion hole 42 Canopy 43 Inner ring 44 Outer ring 46 Outer ring 50 Ceiling fan 51 Top surface 52 Inner surface 53 Shaft opening 54 Inner surface 101 Motor 102 Stator portion 103 Rotor portion 111 Bracket 112 Stator core 113 Coil 114 Bearing 115 Holder Part 116 Core back 117 Teeth part 120 Rotor holder 121 Shaft 122 Cylindrical part 124 Adhesive layer 130 Rotor magnet

Claims

A shaft having a rotation axis,
A stator core fixed to the shaft;
A coil provided to the stator core,
A rotor holder having an aluminum holder outer shell and an inner circumferential surface facing the stator core;
A bearing including an inner ring passing through the shaft and an outer ring fixed to the rotor holder;
An insert ring which is a ferromagnetic metal and is provided on the inner peripheral surface of the rotor holder and annularly covers the inner periphery of the holder outer periphery in the circumferential direction;
A plurality of magnets provided on the inner circumferential surface of the insert ring and arranged in the circumferential direction;
Brushless DC motor with.
The brushless DC motor according to claim 1, wherein the insert ring is formed in a cylindrical shape of a rectangular metal flat plate.
The brushless DC motor according to claim 2, wherein the insert ring is disposed such that circumferential ends of the metal flat plate do not overlap with circumferential ends of the plurality of magnets.
The brushless DC motor according to claim 3, wherein a circumferential center of at least one of the plurality of magnets and a circumferential end of the metal flat plate of the insert ring are aligned with each other.
The brushless DC motor according to claim 1, wherein the insert ring has a cutting surface on the inner circumferential surface of the insert ring.
The holder outer shell is a cylindrical shape having a shaft opening through which the shaft is inserted in the top surface, and has a ring-shaped step so that the inner diameter on the top surface side becomes smaller.
The brushless DC motor according to claim 1, wherein the insert ring and the plurality of magnets abut the step on the top surface side.
The brushless DC motor according to claim 1, wherein a length of the insert ring in the rotational axis direction is larger than a length of each of the plurality of magnets in the rotational axis direction.
A ceiling fan comprising the brushless DC motor according to claim 1.
The ceiling fan according to claim 8, wherein a top side of the brushless DC motor is covered with a canopy.