JP2008141903A - Brushless dc motor and mounted ventilation blower - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brushless DC motor which is formed by integrally molding a printed circuit board on which a plurality of electronic parts are mounted, a motor driving coil, and a stator with resin and is capable of attaining few variations in characteristics, size reduction, high quality, and cost reduction. <P>SOLUTION: An exposed portion 15a which is not molded to allow a part of the printed circuit board 15 to be exposed is provided, and a fuse 5, electrolytic capacitors 7, 9, and a variable resistor 13 which are electronic parts are mounted on the exposed portion. In this way, the electrolytic capacitors 7, 9 are used, molding is performed at a proper temperature, and variations of motor characteristics are adjusted by using the variable resistor. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a brushless DC motor used in, for example, a ventilation fan, and more specifically, a brushless DC motor in which a circuit board for driving the motor and a main part of the motor are molded integrally to improve moisture resistance and safety. And a ventilation blower equipped with the same.

  Conventionally, this kind of brushless DC motor is used in a refrigerator or a ventilation fan that is driven for a long time because it has high efficiency (power saving) and excellent durability.

  However, since this type of brushless DC motor uses a commercial power supply as a power source, it needs AC-DC conversion, and efficiently converts the converted DC voltage exceeding 100 V to about 10 to several tens V suitable for driving the motor. There is a need for a switching power supply type DC-DC converter or the like, or a high-voltage PWM drive system in which the above-described converted DC voltage exceeding 100 V is directly PWM driven to control the average voltage and vary the applied voltage to the motor. It has been.

  For this reason, many electronic parts other than a motor are required compared with the conventional induction motor of an AC direct drive type, and there exists a fault to which a structure becomes complicated.

  Thus, for example, Patent Documents 1 and 2 are known as methods for solving this drawback and compactly configuring the motor.

In Patent Documents 1 and 2, a motor drive coil and a stator excited by the drive coil are mounted on a printed circuit board (circuit board) on which electronic components such as a diode and a smoothing capacitor are mounted, and these are thermoset. It is made to be integrally molded with a compatible resin.
JP 2000-041370 A (FIGS. 5 and 6) JP 2003-319615 A

  However, in such a conventional molded motor, in order to form a compact structure by integrally molding the electronic components, the electronic components used must have heat resistance and pressure resistance, or the molding temperature can be set to an appropriate value. It was necessary to lower the molding pressure.

  In other words, since the resin temperature during molding is about 150 ° C and pressure is applied, the heat-resistant temperature of electrolytic capacitors and fuses is low, and the parts that are covered with a metal or glass outer case and are vulnerable to pressure are electrolyzed. If the capacitor is a ceramic capacitor or film capacitor, if it is a fuse, it is necessary to change it to a resin-sealed type other than a glass tube, or it is necessary to lower the molding temperature to 150 ° C. or lower the molding pressure. The former increases the price of the motor, and the latter has the problem of lowering the molding quality, and is required to be molded at an appropriate temperature and pressure without being restricted by the heat resistance and pressure resistance of the electronic components used. ing.

  The present invention solves such problems and can be molded at an appropriate temperature and pressure without being limited by the heat resistance and pressure resistance of the electronic components used, and uses inexpensive parts. The first object of the present invention is to provide a brushless DC motor that can be compact, has high quality, and is inexpensive.

  In addition, since the electronic parts are integrally molded, there is a problem that adjustment after molding is difficult.

  That is, in order to keep the motor characteristics within a certain level of variation, it is necessary to keep the output voltage of the above-described DC-DC converter within a predetermined range. The DC-DC converter needs to be configured with high-precision parts, and there is a problem that the motor price increases.

  A second object of the present invention is to solve such problems, and to provide a low-cost brushless DC motor with little characteristic variation since the motor characteristic variation can be easily adjusted after molding. Yes.

  Further, since the electronic parts are molded integrally, there is a problem that it is difficult to replace the parts after molding.

  A third object of the present invention is to solve such problems and to provide a brushless DC motor capable of replacing parts after molding.

  In order to achieve the first and second objects, the brushless DC motor of the present invention is a brushless DC motor in which a circuit board on which a plurality of electronic components are mounted, a motor drive coil and a stator are integrally molded with resin. In FIG. 2, a part that is not molded is provided so that a part of the circuit board is exposed, and an electronic component is mounted or connected to the exposed part of the circuit board.

  By this means, it is possible to mold at an appropriate temperature and pressure without being limited by the heat resistance and pressure resistance of the electronic component to be used, and it is possible to use an inexpensive component and to vary motor characteristics after molding. Thus, a brushless DC motor capable of easily adjusting the above is obtained.

  Moreover, when this motor is used for a ventilation blower, the variation in the amount of blown air due to the variation in the size of the blower fan or casing can be adjusted within a predetermined value by correcting the characteristics of the motor.

  In order to achieve the third object, the brushless DC motor of the present invention is provided with connecting means such as terminals on the exposed portion of the circuit board so that electronic components can be connected.

  By this means, not only electrolytic capacitors but also components that require replacement such as fuses can be easily attached after molding.

  According to the present invention, it is possible to provide a low-cost brushless DC motor that is compact and has good quality with little variation in characteristics. Moreover, the ventilation air blower with little variation in the air flow rate can be provided.

  The invention according to claim 1 of the present invention is a brushless DC motor in which a circuit board on which a plurality of electronic components are mounted, a motor drive coil and a stator are integrally molded with resin, and a part of the circuit board is exposed. This is a brushless DC motor provided with a part not molded.

  This makes it possible to mold at the proper temperature and pressure without being limited by the heat resistance and pressure resistance of the electronic components used, and it is compact, high quality, and low price that allows the use of inexpensive parts. A brushless DC motor can be provided.

  A second aspect of the present invention is the brushless DC motor according to the first aspect, wherein a part of the electronic component is mounted on the exposed portion of the circuit board.

  This makes it possible to mold at the proper temperature and pressure without being limited by the heat resistance and pressure resistance of the electronic components used, and it is compact, high quality, and low price that allows the use of inexpensive parts. A brushless DC motor can be provided.

  The brushless DC motor according to claim 3 of the present invention is the brushless DC motor according to claim 2, wherein a connection means such as a terminal is provided on an exposed portion of the circuit board, and a part of the electronic component is connected to the connection means. It is.

  This makes it possible to mold at an appropriate temperature and pressure without being limited by the heat resistance and pressure resistance of the electronic component to be used, so that inexpensive parts can be used, and parts are replaced after molding. Therefore, it is possible to provide a brushless DC motor that is compact, high quality, and low in price.

  According to a fourth aspect of the present invention, in the brushless DC motor according to the second or third aspect, the electronic component to be mounted or connected to the exposed portion of the circuit board has a heat resistance required when molding an electrolytic capacitor or the like. It is a brushless DC motor which is a component with low pressure resistance.

  Thereby, it is possible to provide a brushless DC motor that is compact, can be exchanged after molding, has high quality, and is inexpensive.

  According to a fifth aspect of the present invention, in the brushless DC motor according to the second or third aspect, the electronic component mounted or connected to the exposed portion of the circuit board is for adjusting the characteristics of the motor such as a variable resistor. This is a brushless DC motor.

  As a result, it is possible to provide a compact, high-quality and low-cost brushless DC motor with little characteristic variation that can easily adjust the motor characteristic variation after molding.

  A sixth aspect of the present invention is the brushless DC motor according to the first aspect, wherein a nonmetallic protective frame is provided at a boundary portion between the exposed portion of the circuit board and the resin.

  Thereby, when the circuit board is a double-sided printed board, a compact, high-quality and low-cost brushless DC motor can be provided which does not damage the printed foil by the mold during molding.

  The invention according to claim 7 of the present invention is the brushless DC motor according to claim 6, wherein the protective frame is made of resin.

  Thereby, when the circuit board is a double-sided printed board, a compact, high-quality and low-cost brushless DC motor can be provided which does not damage the printed foil by the mold during molding.

  The invention according to claim 8 of the present invention is the brushless DC motor according to claim 6, wherein the protective frame is filled with a moisture-proof material.

  As a result, it is possible to provide a compact brushless DC motor that can secure the moisture resistance of the motor, is high in quality, and is low in price.

  A ninth aspect of the present invention is the brushless DC motor according to the first aspect, wherein a cover for covering the exposed portion of the circuit board is provided.

  As a result, it is possible to provide a compact, high-quality and low-cost brushless DC motor that can protect the electronic components provided in the exposed portion from external force and can prevent contamination from dust and the like.

  According to a tenth aspect of the present invention, in the brushless DC motor according to the ninth aspect, the cover is a brushless DC motor provided in close contact with a molded part made of metal.

  As a result, it is possible to provide a compact, high-quality, and low-cost brushless DC motor that can release heat from the motor and electronic components and reduce the temperature thereof.

  The invention described in claim 11 of the present invention is the brushless DC motor according to claim 9, wherein the cover is fastened together with an attachment screw of the brushless DC motor to a device using the brushless DC motor. is there.

  As a result, it is possible to provide a compact brushless DC motor that has a reduced number of parts, good assemblability, good quality, and low price.

  A twelfth aspect of the present invention is a ventilating blower equipped with the brushless DC motor according to any one of the first to eleventh aspects.

  This makes it possible to provide a ventilating blower equipped with a compact, high-quality, low-price brushless DC motor with little characteristic variation that can be realized by correcting the motor characteristics by varying the blowing air volume due to variations in the size of the blower fan and casing. Can be provided.

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

(Embodiment 1)
FIG. 1 is a structural external view of a ventilation blower using a brushless DC motor of the present invention, FIG. 1 (a) is a side view of the structural external view of the ventilation blower, and FIG. 1 (b) is a ventilation blower. FIG. 1C is a front view of the structural external view of the ventilation fan.

  The brushless DC motor 2 is attached to the casing 1, and the blower fan 3 is attached to the rotating shaft of the brushless DC motor 2. The ventilation fan is attached to the ceiling, and the brushless DC motor 2 is driven to ventilate the room. .

  FIG. 2 is a diagram showing an example of an electric circuit of a brushless DC motor (hereinafter simply referred to as a motor) of the present invention.

  The brushless DC motor 2 connected to the commercial power supply 4 has a rectifier 6 (bridge diode) connected to the subsequent stage of the fuse 5 and obtains a DC voltage by the electrolytic capacitor 7 connected to the subsequent stage. Further, the voltage is stepped down to a voltage of about several tens of 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. The motor unit connected to the next stage is driven by the DC voltage obtained in this way, and the configuration thereof includes a motor drive circuit 10 (IC), drive coils 11a and 11b, and transistors 12a for exciting these drive coils. 12b.

  The variable resistor 13 is for adjusting a characteristic variation of the motor so that a predetermined performance is obtained, and is provided for adjusting a conduction period of a transistor (not shown) of the DC-DC converter 8. ing. Although not shown, the motor drive circuit 10 is configured to be connected to a detection element such as a Hall element for detecting the position of a rotor (described later).

  FIG. 3 is a view showing the structure of the brushless DC motor of the present invention, FIG. 3 (a) is a view showing an exposed portion of the circuit board of the brushless DC motor, and FIG. 3 (b) is a sectional view of the structure of the brushless DC motor. FIG. 3C is a cross-sectional view taken along the line AB of the circuit board exposed portion of the brushless DC motor.

  As shown in FIG. 3B, the drive coils 11a and 11b described in FIG. 2, the stator 14 excited by the drive coil, and the electronic components such as the motor drive circuit 10 described in FIG. 2 (drive coil 11a). , 11b) is mounted on the circuit board (printed circuit board) 15 with the thermosetting resin 16 integrally. Here, the hatched portion at 45 ° to the right in the figure indicates that it is a thermosetting resin. The terminal 17 is a terminal for supplying commercial power to the circuit board 15.

  In this case, the molding does not cover the entire surface of the circuit board 15, but a part that is not molded is provided so that a part of the circuit board 15 is exposed. The exposed part 15a shows the state.

  A fuse 5, electrolytic capacitors 7 and 9, and a variable resistor 13 are mounted on the outside (upper part) of the exposed portion 15a as shown in FIG.

  As shown in FIG. 3C, the fuse 5 is soldered to connection means 18 which is a rod-like terminal mounted on the circuit board 15.

  Further, a protective frame 19 made of resin is provided on the boundary surface between the outer periphery of the exposed portion 15 a and the thermosetting resin 16, and the protective frame 19 is filled with a moisture-proof material 20.

  As shown in FIG. 3B, the drive coil 11a, 11b, the stator 14, and the circuit board 15 are integrally molded and magnetized as shown in FIG. 3B, the rotor 21, the rotary shaft 22, the bearing 23, and the bracket 24. The motor is configured by attaching

  The cover 25 is attached with a metal plate having good thermal conductivity such as aluminum so as to cover an electronic component such as the electrolytic capacitor 7 mounted on the exposed portion 15a so as to be in close contact with the resin portion of the molding. When the motor 2 is attached to the casing 1a which is a part of the casing 1 of the ventilation fan described above, the motor 2 is attached together with the brushless DC motor 2 with screws 26 at four locations.

  The support 27 is provided to support the circuit board 15 during molding.

  FIG. 4 is a view for explaining the protective frame 19 and the mold at the time of molding.

  Molding is performed by the two-side molds 28 and 29 (the resin injection port is not shown). In this case, it is necessary to make a part of the mold 28 abut on the outer peripheral portion of the exposed portion 15a of the circuit board 15. is there. Then, there exists a possibility that a metal mold | die may contact | abut to the printed foil on the surface of the circuit board 15, and a printed foil may be damaged. 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 so that the mold does not contact the printed foil.

  As described above, in the brushless DC motor of the present invention, the circuit board on which the electronic components are mounted, the drive coil and the stator are integrally formed with a thermosetting resin so that a part of the circuit board is exposed. An electrolytic capacitor, a variable resistor, a fuse or the like is attached to the exposed portion of the wire. For this reason, since molding can be performed at a normal temperature and pressure, an electrolytic capacitor or a fuse having low heat resistance and low pressure resistance can be used without deteriorating the molding quality.

  In addition, since a variable resistor can be mounted, adjustment of the motor is easy, and connection means such as terminals are provided, so that it is possible to replace parts after molding.

  Here, part of the circuit board is a board space for mounting parts with low heat resistance and pressure resistance and motor adjustment parts, such as parts with low heat resistance and pressure resistance and motor adjustment parts. Parts that have a heat-resistant temperature lower than the temperature at the time of molding, motor adjustment parts, etc., parts that have a pressure resistance lower than the pressure at the time of molding, motor adjustment parts, etc., for example, electrolytic capacitors, variable resistors, fuses, etc. and so on.

  Furthermore, since the boundary between the exposed part and the resin on the outer periphery is provided with a protective frame made of resin, there is no risk of damaging the printed foil of the circuit board during molding, and the protective frame is filled with a moisture-proof material. As a result, the moisture-proofing operation is also simplified, and the defect in which the moisture resistance is reduced by providing the exposed portion can be compensated. In addition, since the metallic cover is provided so as to cover the electronic component mounted on the exposed portion, the mounted electronic component is not likely to be damaged by an external force, and contamination by dust can be prevented.

  Further, since the metallic cover is brought into close contact with the molded resin portion, there is an effect of efficiently dissipating heat generated by the motor and the electronic component. Since the cover is attached to the casing together with the motor by fastening, the number of parts is small and assembly is easy.

  Moreover, the ventilation air blower which mounts the brushless DC motor of this invention can adjust the dispersion | variation in the ventilation air flow amount by the dimension variation of a casing or a ventilation fan.

  In the present embodiment, the exposed portion of the circuit board has been described in one place, but a plurality of places may be provided as necessary.

  In the present embodiment, the resin to be molded is described as a thermosetting resin. However, a photo-curing resin such as ultraviolet curing or a thermoplastic resin may be used, and there is no difference in the operational effect.

  Further, although the motor drive coil has been described with two phases and the motor drive circuit with half wave drive, three phase or full wave drive may be used, and there is no difference in the operation and effect.

  Further, the voltage applied to the drive coil is controlled by stepping down using a DC-DC converter, but the motor drive circuit is obtained without obtaining a direct current voltage by an electrolytic capacitor connected to a rectifier (bridge diode) and stepping down the voltage. Alternatively, a high voltage PWM driving method in which PWM driving is directly performed by a transistor via a transistor may be used.

  In addition, although the components for adjusting the characteristics of the motor have been described with variable resistors, switches, resistors, capacitors, oscillators, semiconductors (for example, Zener diodes) and their composites and components themselves may be changed. There is no difference in function and effect.

  In addition, although the connecting means 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) may be provided and molded. You may make it attach the connector of the remote control apparatus for motor capability control to this connector.

  The brushless DC motor of the present invention can provide a compact, high-quality and low-cost brushless DC motor with little characteristic variation, and further can provide a ventilating blower that can reduce variation in the amount of blown air. It can be applied to other household electric appliances.

Structural external view of ventilation fan using brushless DC motor of the present invention ((a) Same as above, side view of structural external view of ventilation blower, (b) Bottom view of structural external view of ventilation blower, (c) ) Same as above, Front view of the structural external view of the ventilation fan The figure which shows an example of the electric circuit of the brushless DC motor of this invention The figure which shows the structure of the brushless DC motor of this invention ((a) Same as the above, The figure which shows the exposed part of the circuit board of a brushless DC motor, (b) Same as the above, The cross-sectional view of the structure of a brushless DC motor, (c) The same, Brushless DC (A-B cross-sectional view of the exposed portion of the circuit board of the motor) Same explanatory diagram about protective frame and mold at the time of molding External view showing a conventional brushless DC motor Circuit diagram showing a conventional brushless DC motor

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Casing 1a Casing 2 Brushless DC motor 3 Blower fan 4 Commercial power supply 5 Fuse 6 Rectifier 7 Electrolytic capacitor 8 DC-DC converter 9 Electrolytic capacitor 10 Motor drive circuit 11a Drive coil 11b Drive coil 12a Transistor 12b Transistor 13 Variable resistor 14 Stator DESCRIPTION OF SYMBOLS 15 Circuit board 15a Exposed part 16 Thermosetting resin 17 Terminal 18 Connection means 19 Protective frame 20 Moisture-proof material 21 Rotor 22 Rotating shaft 23 Bearing 24 Bracket 25 Cover 26 Screw 27 Support 28 Mold 29 Mold

Claims (12)

A brushless DC motor in which a circuit board on which a plurality of electronic components are mounted, a motor drive coil, and a stator are integrally molded with a resin, and the brushless is provided with a portion that is not molded so that a part of the circuit board is exposed. DC motor. The brushless DC motor according to claim 1, wherein some of the plurality of electronic components are mounted outside an exposed portion of the circuit board. 3. The brushless DC motor according to claim 2, wherein connecting means such as terminals are provided outside the exposed portion of the circuit board, and a part of the plurality of electronic components is connected to the connecting means. 4. The brushless DC motor according to claim 2, wherein the electronic component mounted or connected to the exposed portion of the circuit board is a component having low pressure resistance and heat resistance required for molding such as an electrolytic capacitor. 4. The brushless DC motor according to claim 2, wherein the electronic component mounted or connected to the exposed portion of the circuit board is a component for adjusting the characteristics of the motor such as a variable resistor. The brushless DC motor according to claim 1, wherein a nonmetallic protective frame is provided at a boundary portion between the exposed portion of the circuit board and the resin. The brushless DC motor according to claim 6, wherein the protective frame is made of resin. The brushless DC motor according to claim 6, wherein a moisture-proof material is filled in the protective frame. The brushless DC motor according to claim 1, wherein a cover that covers the exposed portion is provided on the exposed portion of the circuit board. The brushless DC motor according to claim 9, wherein the cover is made of metal and is in close contact with a molded part. The brushless DC motor according to claim 9, wherein the cover is fastened together with an attachment screw of the brushless DC motor to a device using the brushless DC motor. The ventilation air blower which mounts the brushless DC motor in any one of Claims 1 thru | or 11.

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