WO2008069166A1

WO2008069166A1 - Brushless dc motor and a ventilator using the same

Info

Publication number: WO2008069166A1
Application number: PCT/JP2007/073291
Authority: WO
Inventors: Takayuki Tahara; Matsuo Shiraishi; Shigeki Yamane
Original assignee: Panasonic Corporation
Priority date: 2006-12-05
Filing date: 2007-12-03
Publication date: 2008-06-12
Also published as: JP2008141903A

Abstract

A brushless DC motor includes: a stator having a stator core, a drive coil wound on the stator core, a circuit substrate on which a plurality of electronic parts are mounted, and a mold resin unit which molds them as a unitary block; and a rotor arranged to oppose to the stator with a predetermined gap. The mold resin unit has a window where a part of a circuit substrate is exposed. On the circuit substrate exposed in the window, some of the electronic parts including at least one of an electrolyte capacitor, a variable resistor, and a fuse are mounted.

Description

Specification

Brushless DC motor and ventilation blower equipped with the same

Technical field

TECHNICAL FIELD [0001] The present invention relates to a brushless DC motor used in a ventilation blower, and relates to a brushless DC motor configured by integrally molding a circuit board unit for driving a motor and main parts of the motor, and a ventilation equipped with the brushless DC motor. The present invention relates to a blower.

Background art

[0002] Conventionally, this type of brushless DC motor is widely used in refrigerators and ventilation fans that are driven for a long time because of its high efficiency, low power consumption, and excellent durability.

[0003] However, since this type of brushless DC motor uses commercial power as its power source, it needs AC-DC conversion, and the converted DC voltage of over 100V can be reduced to about 10 to 10V, which is suitable for driving the motor. A switching power supply type DC-DC converter that efficiently steps down is required. Furthermore, when performing sinusoidal drive, a high-voltage PWM drive circuit is required to vary the applied voltage to the motor by directly PWM driving the converted DC voltage exceeding 100V.

[0004] For this reason, as compared with a conventional AC direct drive type induction motor or the like, a large number of electronic components other than a motor are required, and there is a drawback that the structure is complicated. Thus, for example, Patent Documents 1 and 2 are known as methods for solving this drawback and compactly configuring the motor.

FIG. 5 is an external perspective view of a conventional brushless DC motor disclosed in these patent documents. In FIG. 5, a stator 114 includes a stator core (not shown), a drive coil (not shown) wound around the stator core, a circuit board 11 5 on which a plurality of electronic components 135 are mounted, and those Is formed by a mold resin portion 116 for integrally molding. The rotor 121 has a permanent magnet (not shown) on the outer periphery thereof, and is opposed to the stator core via a predetermined gap. The rotor 121 has a rotating shaft 122 fixed at the center and is rotatably supported by a bearing (not shown). Many circuit boards 115 The electronic component 135 is mounted, and is further connected to a power supply terminal 117 for supplying commercial power from the outside and for exchanging signals with the outside of the motor as necessary.

FIG. 6 is an electric circuit diagram of a conventional brushless DC motor. The brushless DC motor is connected to the commercial power supply 104 and is generally supplied with 100V AC. This commercial power supply is converted into a high-voltage DC voltage through a fuse 105 by a rectifier 106 (bridge diode) and an electrolytic capacitor 107 connected to the subsequent stage. Further, it is stepped down to a voltage of about a few tens of volts by the DC-DC converter 108 connected to the next stage, and smoothed again by the electrolytic capacitor 109. As this DC-DC converter 108, a so-called switching power supply type is often used in which a transistor is intermittently connected and smoothed by a choke coil (not shown) and a capacitor.

[0007] The low-voltage DC voltage force thus obtained is supplied to the motor unit connected to the next stage, and is driven in a predetermined direction and a predetermined rotation speed. The motor rotor 121 is provided with a permanent magnet (not shown), and its magnetic pole position is detected by a position detection element (not shown) such as a Hall element. In accordance with the magnetic pole position, the motor drive circuit 110 (IC) generates a motor drive signal, switches the transistors 112a and 112b, and excites the drive coils 1 11a and 11 lb.

However, in such a conventional molded motor, a stator core, a drive coil wound around the stator core, and a circuit board on which a plurality of electronic components are mounted are integrally molded. In order to mold, there was a great restriction on the electronic parts to be used. That is, the temperature of the molten resin at the time of molding is about 150 ° C, and it is necessary to mold with a large pressure. Naturally, the electronic components used must withstand such temperatures and pressures. For example, electrolytic capacitors and fuses must be used strictly.

[0009] One countermeasure is to lower the molding temperature and molding pressure. However, this measure reduces the molding quality. Another measure is to replace electronic components with ones that can withstand the molding temperature and pressure. For electrolytic capacitors, ceramic capacitors can be replaced with film capacitors, and for fuses, resin sealed types other than glass tubes can be replaced. However, this measure increases the cost of the product and hinders the reduction in size and weight of the product. Furthermore, when it is necessary to adjust the motor characteristics with a variable resistor or the like, since this variable resistor has a movable part, it is difficult to integrally mold it. For this reason, the variable resistor is placed outside the motor and connected via a terminal, which increases costs. In addition, if the fuse is molded into the above-mentioned shape and integrated with the mold, it cannot be replaced if it is cut for some reason, and some measures are required.

Patent Document 1: Japanese Patent Laid-Open No. 2000-041370

Patent Document 2: Japanese Patent Laid-Open No. 2003-319615

Disclosure of the invention

The brushless DC motor of the present invention has the following configuration.

[0012] A stator having a stator core, a drive coil wound around the stator core, a circuit board on which a plurality of electronic components are mounted, and a mold resin portion for integrally molding them. The mold resin part includes a window part that exposes a part of the circuit board. The mold resin part includes a rotor that has a rotation axis and faces the stator through a predetermined gap. Further, a part of the plurality of electronic components is mounted on the circuit board exposed in the window.

[0013] A part of the plurality of electronic components includes at least one of an electrolytic capacitor, a variable resistor, and a fuse.

[0014] Furthermore, the present invention includes a ventilation blower equipped with a brushless DC motor.

[0015] With this configuration, electronic components that are sensitive to high pressure and high heat can be placed outside the mold, so that molding can be performed at a normal temperature and pressure, so that the molding quality is not reduced. Electronic components with low pressure resistance such as electrolytic capacitors can be used.

[0016] Further, after the completion of the assembly of the motor, the force S is required to mount the variable resistor necessary for adjusting the motor characteristics.

[0017] Further, replacement is facilitated by providing a fuse in the window.

[0018] In addition, a ventilation blower equipped with a brushless DC motor having such characteristics can be provided.

Brief Description of Drawings

[0019] [FIG. 1A] FIG. It is a front view of a wind machine.

1B] Fig. 1B is a bottom view of the ventilation fan.

1C] Fig. 1C is a side view of the ventilation fan.

FIG. 2 is an electric circuit diagram of the brushless DC motor according to the embodiment of the present invention.

FIG. 3A is a top view showing details of a window portion of the brushless DC motor in the embodiment of the present invention.

FIG. 3B is a structural sectional view of the brushless DC motor according to the embodiment of the present invention.

FIG. 3C is a cross-sectional view taken along the line 3C-3C in FIG. 3A.

[FIG. 4] FIG. 4 is an explanatory diagram of molding of the brushless DC motor in the embodiment of the present invention.

FIG. 5 is an external perspective view of a conventional brushless DC motor.

FIG. 6 is an electric circuit diagram of a conventional brushless DC motor.

Explanation of symbols

1, la casing

2 Brushless DC motor

3 Blower fan

4 Commercial power

5 fuse

6 Rectifier

7, 9 Electrolytic capacitor

8 DC—DC converter

10 Motor drive circuit

11a, l ib drive coil

12a, 12b 卜 Transistor

13 Variable resistor 14a Stator core

15 Circuit board

16 Mold resin part

16a Window

17 Power supply terminal

18 Connection terminal

19 Small ^ 蒦 ^!

20 Moisture-proof material

21 Rotor

22 Rotating shaft

23 Bearing

24 Bracket

25 Kano Kuichi

26 screws

27 Support

28 Upper mold

29 Lower mold

31 Norenichi

35 na |;) Loro

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0022] (Embodiment)

FIG. 1A is a front view of a ventilation blower using a brushless DC motor according to an embodiment of the present invention, FIG. 1B is a bottom view of the same, and FIG. 1C is a side view of the same. This ventilation blower has a structure in which a brushless DC motor 2 is attached to a casing 1 and a blower fan 3 (sirocco fan) is attached to a rotating shaft of the brushless DC motor 2. This ventilation blower is attached to a ceiling or the like, and the brushless DC motor 2 is driven to blow air from the louver 31 to ventilate the room. FIG. 2 is an electric circuit diagram of the brushless DC motor according to the embodiment of the present invention.

The brushless DC motor 2 is connected to the commercial power source 4 via the power terminal 17 and supplied with commercial power (generally AC 100 V). This commercial power supply is converted into a high-voltage DC voltage by a rectifier 6 (bridge diode) through a fuse 5 and an electrolytic capacitor 7 connected to the subsequent stage. Further, the voltage is reduced to about 10 or more volts by the DC-DC converter 8 connected to the next stage, and smoothed again by the electrolytic capacitor 9. As this DC-DC converter 8, a so-called switching power supply type is often used in which a transistor is intermittently connected and smoothed by a choke coil (not shown) and a capacitor. This output voltage can be adjusted with the variable resistor 13. This variable resistor 13 is for adjusting the characteristic variation of the motor so that the predetermined performance is obtained. By adjusting the conduction period of the transistor (not shown) of the DC—DC converter 8, the DC— The output voltage of DC converter 8 is adjusted.

[0025] The low-voltage direct current voltage force thus obtained is supplied to the motor unit connected to the next stage, and is driven in a predetermined direction and a predetermined rotation speed. A motor rotor (described later) is provided with a permanent magnet (not shown), and its magnetic pole position is detected by a position detection element (not shown) such as a Hall element. The motor drive circuit 10 (IC) generates a motor drive signal according to the magnetic pole position, switches the transistors 12a and 12b, and excites the drive coils 1la and ib.

3A, 3B, and 3C show the structure of the brushless DC motor of the present invention. FIG. 3A is a top view of the brushless DC motor according to the embodiment of the present invention, and particularly shows details of the window. FIG. 3B is a structural cross-sectional view of the brushless DC motor in the present embodiment, and FIG. 3C is a cross-sectional view of 3C-3C in FIG. 3A.

[0027] As shown in FIG. 3B, the stator 14 is a circuit board on which a stator core 14a, drive coils l la and l ib wound around the stator core 14a, and a plurality of electronic components 35 are mounted. 15 and a mold resin portion 16 for integrally molding them. The rotor 21 has a permanent magnet (not shown! /) On its outer periphery, and faces the stator core 14a with a predetermined gap. The rotor 21 has a rotating shaft 22 fixed at the center and is rotatably supported by a bearing 23. [0028] On the circuit board 15, many electronic components 35 shown in the electric circuit diagram of Fig. 2 are mounted. Furthermore, the circuit board 15 includes a power supply terminal 17 for supplying commercial power from the outside and a support body 27 for supporting the circuit board 15 during molding.

[0029] The mold resin portion 16 is formed by integrally molding the stator core 14a, the drive coils lla and ib, and the circuit board 15. The mold resin portion 16 is provided with a window portion 16a so as to expose a part of the circuit board 15 that does not cover the entire surface of the circuit board 15. As shown in FIG. 3A, a fuse 5, electrolytic capacitors 7 and 9, and a variable resistor 13 are mounted on the portion of the circuit board 15 located in the window portion 16a. Of the electronic components 35, other electronic components such as the motor drive circuit 10 are completely covered by the mold resin portion 16. As shown in FIG. 3C, the fuse 5 is soldered to a rod-like connection terminal 18 mounted on the circuit board 15.

[0030] Further, a protective frame 19 made of resin is provided at a boundary portion of the mold resin portion 16 that forms the window portion 16a, and the protective frame 19 is filled with a moisture-proof material 20.

[0031] The cover 25 is a metal plate having good thermal conductivity such as aluminum, and covers the electronic components mounted on the circuit board 15 of the window portion 16a so as to be in close contact with the mold resin portion. Attached. When the brushless DC motor 2 is attached to the casing l a which is a part of the above-described ventilation blower casing 1, it is attached together with the brushless DC motor 2 with the screw 26 at the four power points. As a result, the cover 25 serves to protect the electronic component 35 exposed at the window portion 16a and to dissipate heat generated mainly by the drive coils lla and ib.

[0032] As a material of the mold resin portion 16, a thermosetting resin, for example, an unsaturated polyester resin is preferable. In order to increase strength and improve dimensional accuracy, fillers are generally included in an appropriate ratio.

[0033] After inserting the rotor 21 into the stator 14, the bracket 24 is fixed and the brushless DC motor is fixed.

2 is completed. The outer ring of one bearing 23 is fixed to the mold resin part 16 and the other bearing 2

The outer ring of 3 is fixed to the bracket 24.

[0034] Next, FIG. 4 is an explanatory diagram of molding of the brushless DC motor in the embodiment of the present invention. Realize stator core 14a and electronic components 35 wound with drive coils l la and l ib The mounted circuit board 15 is molded by the upper mold 28 and the lower mold 29 (the resin inlet is not shown). In this case, a part of the upper mold 28 needs to abut on the outer peripheral portion of the portion corresponding to the window portion 16a of the circuit board 15. As a result, the mold may come into contact with the printed foil on the surface of the circuit board 15 to damage the printed foil. Therefore, a protective frame 19 made of resin is provided, and the mold is in contact with the protective frame 19, and the printed foil is protected by preventing the mold from contacting the printed foil.

[0035] As described above, the brushless DC motor of the present embodiment has a thermosetting property of the circuit board 15 on which the electronic component 35 is mounted and the stator core 14a around which the drive coils l la and l ib are wound. A window is provided so that a part of the circuit board 15 is exposed with resin, and is molded integrally. The fuse 5, the electrolytic capacitors 7, 9 and the variable resistor 13 are attached to the portion corresponding to the window portion 16a of the circuit board 15.

[0036] With this configuration, when the drive coils l la, l ib, the stator core 14a, and the circuit board 15 are integrally molded with the mold resin portion 16, the window portion 16a is excluded and the module is removed. It can be molded. As a result, the mold resin portion 16 that does not apply high pressure or high heat to the fuse 5 or the electrolytic capacitors 7 and 9 attached to the window portion 16a can be molded at the required normal high pressure and temperature. For this reason, molding can be performed at a normal temperature and pressure, so that the quality of molding does not deteriorate and electrolytic capacitors and fuses with low heat resistance and pressure resistance can be used.

[0037] Further, since the variable resistor 13 is provided in this window portion, it is easy to adjust the motor characteristics such as the rotation speed after the completion of the motor assembly. In addition, since the fuse 5 is also provided in this window portion and soldered to the connection terminal 18, it can be easily replaced even when the fuse is cut for some reason.

[0038] Here, by providing a window 16a in the mold resin part 16 and exposing a part of the circuit board, a part having low heat resistance and pressure resistance, a motor adjustment part and a replacement part are mounted on this part. To do. With this configuration, it is not necessary to lower the molding temperature and molding pressure due to component restrictions, so that good molding quality and high productivity can be realized. In addition, it is easy to adjust the motor characteristics such as the number of revolutions after the motor assembly is completed, and it is possible to achieve uniform motor characteristics. Also, replacement parts such as fuses in the market after shipment Can be replaced, and high maintainability can be realized.

Furthermore, since the protective frame 19 made of resin is provided on the outer peripheral portion of the portion corresponding to the window portion 16a of the circuit board 15, there is no possibility of damaging the printed foil of the circuit board at the time of molding. Further, since the moisture-proof material 20 is filled in the protective frame 19, the moisture-proofing work is also simplified, and the defect in which the moisture resistance is reduced by providing the window portion 16a can be complemented. In addition, since the metallic cover 25 is provided so as to cover the electronic component mounted on the window portion 16a, it is possible to prevent contamination by dust that can cause the mounted electronic component to be damaged by external force.

[0040] Further, since the metallic cover 25 is provided so as to be in close contact with the mold resin portion 16, there is an effect of efficiently dissipating heat generated by the motor and the electronic component. The cover 25 is attached to the casing together with the motor by tightening, so the number of parts is small and assembly is easy.

[0041] Further, in the ventilation blower equipped with the brushless DC motor of the present invention, the variation of the blown air volume due to the dimensional variation of the casing blower fan is adjusted by the variable resistor 13 provided in the window portion 16a. I'll do it.

[0042] In the present embodiment, the windows 16a may be provided at a plurality of locations as required for the force described in one force location.

[0043] In this embodiment, the resin to be molded is described as a thermosetting resin. However, there is no difference in the effect of using a photocurable resin such as ultraviolet curing or a thermoplastic resin.

[0044] Although the motor drive coil has been described with two phases and the motor drive circuit with half-wave drive, there is no difference in the operational effect between three-phase and full-wave drive.

[0045] Although the DC-DC converter is used to step down the voltage applied to the drive coil, the DC voltage is obtained by the electrolytic capacitor connected to the rectifier (bridge diode), and the voltage is not stepped down. It is also possible to use a high-voltage PWM drive system that directly drives PWM with a transistor via a motor drive circuit! / ヽ.

[0046] The components for adjusting the characteristics of the motor have been described using variable resistors. However, even if switches, resistors, capacitors, oscillators, semiconductors (for example, Zener diodes), composites thereof, or components themselves are changed. There is no difference in the effect of the squirrel. [0047] Although the connection terminal 18 has been described as a rod-shaped terminal, it may be a contact type such as a fuse holder or a copper foil (land) for surface mounting, or a connector terminal (male). Install the connector of the remote control device for motor capacity control to this connector after molding.

Industrial applicability

[0048] The brushless DC motor of the present invention and the ventilation blower equipped with the brushless DC motor can realize high efficiency, small size, light weight, high quality, and low price with little variation in characteristics, so that it can be used as a ceiling ventilation fan, refrigerator, and dehumidifier. It can be widely applied as a built-in motor for household electric appliances such as air conditioners.

Claims

The scope of the claims

[1] Brushless DC motor,

A stator core, and a drive coil wound around the stator core;

A circuit board on which a plurality of electronic components are mounted;

A stator having a mold resin portion for integrally molding the stator core, the drive coil, and the circuit board;

The mold resin portion includes a window portion that exposes a part of the circuit board. The rotor includes a rotor that has a rotation axis and faces the stator via a predetermined gap.

[2] The brushless DC motor according to claim 1,

A part of the plurality of electronic components is mounted on the circuit board exposed in the window.

[3] A brushless DC motor according to claim 2,

Some of the plurality of electronic components include electronic components that adjust the motor performance, and the motor performance can be adjusted via the window.

[4] The brushless DC motor according to claim 2,

The circuit board includes a connection terminal, a part of the plurality of electronic components is fixed to the connection terminal, and the electronic component fixed to the connection terminal is detachable through the window portion.

[5] The brushless DC motor according to claim 2,

Some of the plurality of electronic components include at least one of an electrolytic capacitor, a variable resistor, and a fuse.

[6] The brushless DC motor according to claim 1,

The mold resin portion is formed by molding an unsaturated polyester resin.

[7] The brushless DC motor according to claim 1,

The mold resin portion further includes a protective frame at a boundary portion that forms the window portion.

[8] The brushless DC motor according to claim 7,

The protective frame is made of resin, and a molding die at the time of molding the mold resin portion is

, Abuts against the protective frame.

[9] The brushless DC motor according to claim 7,

A dampproof agent is filled in the protective frame.

[10] The brushless DC motor according to claim 1,

The mold resin portion includes a cover that covers the window portion.

[11] The brushless DC motor according to claim 10,

The cover is made of metal and covers the electronic component and is provided in close contact with the mold resin portion.

[12] The brushless DC motor according to claim 10,

The cover is also tightened with a mounting screw of the brushless DC motor.

[13] A ventilation blower equipped with the brushless DC motor according to any one of claims 1 to 12.