JP2006060889A - Circuit board and electric blower - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make uniform temperature rise in a radiator on a circuit board in which multiple power devices are brought into contact with the radiator and cooled, and thereby enhance the reliability of the circuit board. <P>SOLUTION: The circuit board 1 has an upper arm-side power device 7 and a lower arm-side power device 7 with respect to each phase, and is mounted with a three-phase inverter circuit 3 by which these power devices 7 are driven by 120 degree energization. The power devices 7 are arranged on a line in contact with the radiator 8 so that the power devices 7 in the same phases adjoin to each other. The order of arrangement of the upper arm-side power device 7c and the lower arm-side power device 7d in the phase positioned in the center of the three phases is made opposite to the order of arrangement of the upper arm-side power devices 7a and 7e and the lower arm-side power devices 7b and 7f in the other two phases. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a circuit board having a three-phase inverter circuit and an electric blower using the circuit board.

  One of the points to be particularly noted in a circuit board having a three-phase inverter circuit using a power device such as a vacuum cleaner or a power tool, and an electric device equipped with a brushless DC motor using the circuit board is that the inverter circuit is This is a measure against heat generation of a plurality of power devices.

  As one countermeasure against heat generation, a technique is disclosed in which a plurality of power devices are cooled by being brought into thermal contact with a radiator (see, for example, Patent Document 1). In this way, by cooling a plurality of power devices in thermal contact with the heat radiating body, it is possible to reduce the size of the device while taking measures against heat generation, and to obtain advantages in manufacturing the heat radiating body.

  Here, for example, in a three-phase brushless DC motor used in a rechargeable vacuum cleaner, a current of 10 A or more flows through a power device mounted on a circuit board. The rechargeable vacuum cleaner is particularly desired to be downsized, and such a large current flows. Therefore, it is important to achieve both downsizing and circuit reliability. Therefore, it is necessary to ensure the heat dissipation effect while minimizing the heat dissipation body by a technique such as Patent Document 1.

JP 11-318695 A

  However, when a plurality of power devices are in thermal contact with the heat dissipator, mutual heat interference between the generated power devices occurs. At this time, the possibility that the power device that receives the most heat breaks down before other power devices increases. When one power device fails, the problem arises that the circuit board must be replaced even though the other power device is still usable.

  In the technique disclosed in Patent Document 1, when a plurality of power devices are brought into thermal contact with a heat radiating body, a hole or the like is provided in a mutual interference portion due to heat conduction from the plurality of power devices in the heat radiating body. It is configured to weaken the interference. However, in this case, since the heat radiation area may be reduced by providing a hole or the like, the cooling effect on the heat generated by the power device is reduced in the first place, which is a problem.

  An object of the present invention is to make the temperature rise of a heat radiator uniform and improve the reliability of the circuit board in a circuit board that cools a plurality of power devices in thermal contact with the heat radiator.

  The present invention includes a plurality of power devices that are mounted on a radiator and constitute an upper arm, and a plurality of power devices that constitute a lower arm, and these power devices are driven by a 120-degree energization method. In the circuit board on which the phase inverter circuit is mounted, among the power devices, the upper arm power device constituting the same phase and the lower arm power device are arranged so as to be adjacent to each other as a pair, The power device on the upper arm side and the power device on the lower arm side in the phase located in the center of the three phases are arranged in the order of the power device on the upper arm side and the lower arm side in the other two phases. It was made to be reverse with respect to the order of arrangement with the power device.

  ADVANTAGE OF THE INVENTION According to this invention, the temperature rise of the heat radiator which a several power device contacts thermally can be equalize | homogenized, and the reliability of a circuit board can be improved.

  A first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is an external perspective view showing a circuit board 1 of the present embodiment. The circuit board 1 is roughly divided into a drive circuit 2 and a three-phase inverter circuit 3. The drive circuit 2 includes a control unit 5 including a control IC 4 and a circuit portion including electronic components such as a gate resistor 6. The three-phase inverter circuit 3 has six MOSFETs (7a, 7b, 7c, 7d, 7e, 7f) which are power devices. These MOSFETs 7 are six identical types of N-channel MOSFETs 7 having substantially the same on-resistance loss, and are arranged in contact with the radiator 8. The six MOSFETs 7 constituting the three-phase inverter circuit 3 are arranged distributed on one side edge in the longitudinal direction of the circuit board 1 and are in contact with the heat radiator 8. In addition, the power supply unit 10 is disposed substantially opposite to the two side edges in the short direction of the circuit board 1. One power supply unit 10 is connected to a plus side 100a (see FIG. 4) of a DC power source 100 as a power source, and the other power supply unit 10 is connected to a minus side 100b of the DC power source 100. For example, a tab terminal 10 a (see FIG. 2) is attached to the power supply unit 10, and the DC power supply 100 and the circuit board 1 can be connected.

  The radiator 8 is made of a metal such as aluminum formed by extrusion molding or die casting. The heat radiating body 8 is arranged at a substantially right angle to the circuit board 1.

  FIG. 2 is an external perspective view showing another example of the circuit board 1. This another example shows an example in which the arrangement direction of the MOSFET 7 is changed with respect to FIG. In this example, the MOSFET 7 and the heat radiating body 8 are provided substantially horizontally with respect to the circuit board 1. Also in this case, as in FIG. 1, the MOSFETs 7 are distributed and arranged on one side edge in the longitudinal direction of the circuit board 1, and are in contact with the radiator 8.

  FIG. 3A is a front view showing the terminal arrangement of the lead insertion type MOSFET 20, and FIG. 3B is a front view showing the terminal arrangement of the surface mount MOSFET 21. In each MOSFET 20, 21, a gate terminal 30 as a control terminal, a drain terminal 31 as one controlled terminal, and a source terminal 32 as the other controlled terminal are provided from the left side in the front view of FIG. Yes.

  FIG. 4 is a circuit diagram showing a schematic circuit configuration of the drive circuit 2 and the three-phase inverter circuit 3. When a signal (for example, an output signal of the Hall IC) from the rotor magnet signal processing circuit (not shown) is input to the control IC 4 in the control unit 5, the drive circuit 2 sends a control signal to the three-phase inverter circuit 3. It is the structure which outputs. This control signal is output toward each gate terminal 30 of the MOSFET 7 and becomes a gate signal. Here, a voltage of about 10 V is applied to the gate terminal 30 in order to switch the MOSFET 7. At this time, a gate signal is applied to the gate terminal 30 through the gate resistor 6 having an optimum size determined from the switching characteristics of the MOSFET 7.

  Each phase of the three-phase inverter circuit 3 includes (MOSFETs 7a, 7b), (MOSFETs 7c, 7d), and (MOSFETs 7e, 7f). Here, the MOSFETs 7a, 7c, and 7e constitute the upper arm 40 side of the three-phase inverter circuit 3, and the MOSFETs 7b, 7d, and 7f constitute the lower arm 41 side. Such a pair of the MOSFET 7 on the upper arm 40 side and the MOSFET 7 on the lower arm 41 side in each phase is defined as one unit. That is, 7a and 7b, 7c and 7d, and 7e and 7f are set as one unit. The drain terminal 31 of the MOSFET 7 on the upper arm 40 side is connected to the plus side 100 a of the DC power supply 100. The source terminal 32 of the MOSFET 7 on the upper arm 40 side is connected to the drain terminal 31 of the MOSFET 7 on the lower arm 41 side. The source terminal 32 of the MOSFET 7 on the upper arm 40 side and the drain terminal 31 of the MOSFET 7 on the lower arm 41 side are connected to the three-phase load 101. The source terminal 32 of the MOSFET 7 on the lower arm 41 side is connected to the negative side 100 b of the DC power supply 100 via the current detection resistor 42. These MOSFETs 7 are driven based on the gate signal output from the drive circuit 2 and supply an alternating current to the three-phase load 101.

  All of the three-phase three-unit MOSFETs 7 shown in FIG. 4 are arranged in contact with the radiator 8 as shown in FIGS. 1 and 2. At this time, the MOSFETs 7 constituting each unit are arranged so as to be adjacent to each other. Furthermore, the arrangement of one unit of MOSFET 7 arranged in the center among the three-phase three units is opposite to the arrangement of the other two units of MOSFET 7. That is, as shown in FIG. 1 and FIG. 2, six MOSFETs 7 (upper arm 40 side MOSFET 7a, lower arm 41 side MOSFET 7b), (lower arm 41 side MOSFET 7d, upper arm 40 side MOSFET 7c), ( The upper arm 40 side MOSFET 7e and the lower arm 41 side MOSFET 7f) are arranged in this order.

  FIG. 5 is a time chart of a control signal (gate signal) output to the gate terminal 30 of the MOSFET 7 in the 120-degree energization method. Here, the three phases are U, V, and W phases. In the driving of the MOSFET 7 on the upper arm 40 side and the MOSFET 7 on the lower arm 41 side in a certain phase, there is always a non-energization section between them. As an example, attention is focused on the MOSFET 7a on the U-phase upper arm 40 side and the MOSFET 7b on the U-phase lower arm 41 side. In the section (1) and the section (2), only the MOSFET 7a is used, and in the section (4) and the section (5), only the MOSFET 7b is used as the energizing section. The sections (3) and (6) sandwiched between these are non-energized sections. Further, any two MOSFETs 7 among all the MOSFETs 7 are energized within the same section.

  The operation of the three-phase inverter circuit 3 will be described using such a 120-degree energization time chart. Here, among the three-phase three-units described above, one unit at the center arranged opposite to the other two units is the V-phase.

  In section (1) of FIG. 5, the drive circuit 2 outputs a gate signal to the gate terminals 30 of the MOSFETs 7a and 7d. As a result, a current path is formed from the positive side 100 a of the DC power supply 100 to the MOSFET 7 a, the current detection resistor 42, and the negative side 100 b of the DC power supply 100 via the MOSFET 7 a and the three-phase load 101 outside the three-phase inverter circuit 3. At this time, as shown in FIG. 1, the MOSFET 7b which is not energized is sandwiched between the MOSFET 7a and the MOSFET 7d which are energized.

  Similarly, in the section (2), the drive circuit 2 outputs a gate signal to the MOSFETs 7a and 7f. At this time, the MOSFETs 7a and 7f on both sides of the MOSFET 7 array in FIG. 1 operate. Between these two MOSFETs 7, MOSFETs 7b, 7d, 7c and 7e which are in a non-energized state are sandwiched. Further, in section (3), MOSFET 7c and MOSFET 7f are energized, in section (4) MOSFET 7c and MOSFET 7b, in section (5) MOSFET 7e and MOSFET 7b, and in section (6) MOSFET 7e and MOSFET 7d are energized. When the section (6) ends, the MOSFET 7a and the MOSFET 7d are energized again. In any section, one or more MOSFETs 7 that are not energized exist between the two MOSFETs 7 that are energized.

  Here, for example, when a three-phase brushless DC motor using a Y-connected or Δ-connected winding is used as the three-phase load 101, a rotating magnetic field is generated in the winding (three-phase load 101) by the above-described operation. Rotate the motor. Although the above has been described with reference to FIG. 1, FIG. 2 is another example of the circuit board 1 and is the same as FIG. 1.

  Thus, when one unit arranged in the center is arranged opposite to the other two units and the three-phase inverter circuit 3 is driven by the 120-degree energization method, the adjacent MOSFETs 7 are not energized at the same time. . One or more non-energized MOSFETs 7 always exist between the two MOSFETs 7 energized at the same time. For this reason, since the local heat_generation | fever of the heat radiator 8 can be avoided, the temperature rise of the heat radiator 8 is made uniform. Thereby, the reliability of the circuit board 1 can be improved.

  The MOSFET 7 constituting the upper arm 40 and the MOSFET 7 constituting the lower arm 41 are of the same type (in this embodiment, the N-channel MOSFET 7 having the same on-resistance loss). This has the effect of making the heat generation during the operation of the inverter circuit 3 uniform.

  In addition, since the plurality of power devices are cooled by being brought into thermal contact with the heat radiator, adjacent MOSFETs 7 do not operate during the operation of a certain MOSFET 7. For this reason, the influence of heat generation from the adjacent MOSFET 7 at a certain moment can be reduced. For example, when a three-phase brushless DC motor using a Y-connected or Δ-connected winding is used as the three-phase load 101, the sections (1) to (6) in FIG. It is possible to balance the heat generation of the radiator 8 by energization.

  Here, a single heat radiating plate in which the heat radiating fins 8a are formed is used as the heat radiating body 8, but it is also possible to adopt another configuration. For example, since the circuit board 1 is usually inside the electronic device, the frame of the electronic device can be used as the radiator 8. Moreover, although the heat-radiating body 8 formed by extrusion molding or die-casting is used here, other configurations are possible. That is, when there are a large number of radiators 8 and they are thermally connected, they are the same as the radiators 8 formed by extrusion molding or die casting.

  The MOSFET 7 shown in FIGS. 1 and 2 is a lead insertion type MOSFET 20, but the present invention is not limited to this, and the surface mount type MOSFET 21 shown in FIG. In the case where the surface mount type MOSFET 21 is employed, the heat radiating portion ** of the surface mount type MOSFET 21 is mounted in contact with the circuit board 1, so that the circuit board 1 itself functions as the heat radiator 8. Therefore, in this case, the heat radiator 8 independent of the circuit board 1 is not necessary. Further, when the circuit board 1 is used as the heat radiating body 8, since a specific region of the circuit board 1 is prevented from being concentrated and heat is generated, deformation of the circuit board 1 can be suppressed and reliability is improved. Further, in the surface-mount MOSFET 21, by making the heat generation uniform, the circuit board 1 containing a glass material is conventionally required, whereas the circuit board 1 containing no glass material can be used.

  Further, although a MOSFET is used here as a power device, the present invention is not limited to this. A three-terminal power device having a control terminal on the left side when viewed from the front, for example, a switching element such as a bipolar transistor or IGBT (Insulated Gate Bipolar Transistor) can also be used.

  Here, the mounting structure of the MOSFET 7 of the phase not reversely arranged will be described in detail. FIG. 6 shows a bent (lead forming) shape of each terminal of the lead insertion type MOSFET 20. (A) shows the lead insertion type MOSFET 20 for vertical placement, and (b) shows the lead insertion type MOSFET 20 for horizontal placement. FIG. 7 is a perspective view showing a solder surface wiring pattern for one unit of MOSFET 7 on the circuit board 401. (A) shows the case of using the lead insertion type MOSFET 20 for vertical placement, and (b) shows the case of using the lead insertion type MOSFET 20 for horizontal placement.

  As shown in FIGS. 6A and 6B, the lead insertion type MOSFET 20 is a controlled terminal. As shown in FIG. 7, the MOSFET 7 on the upper arm 40 side is arranged on the left hand side and the MOSFET 7 on the lower arm 41 side is arranged on the right side when viewed from the upper surface 401 a (in this case, the solder surface) side of the circuit board 401. By arranging in this way, the gate terminal 30 of the MOSFET 7 constituting the lower arm 41 side is on the leftmost side. At this time, the drain terminal 31 of the upper arm 40 side MOSFET 7 and the positive side 100 a of the DC power supply 100 are connected via the power supply line 59. The drain terminal of the lower arm 41 side MOSFET 7 is connected to the source terminal 32 of the upper arm 40 side MOSFET 7 and the three-phase load 101 via the connection line 60. At this time, on the upper surface 401a, the line connected to the power line 59, that is, the positive side 100a of the DC power source 100 and the negative side 100b via the current detection resistor 42, and the connection line 60 are arranged without intersecting each other. To do. The gate resistor 6 (not shown in FIG. 7) is mounted on the back surface (component surface) of the circuit board 401.

  FIG. 8 is a plan view showing an arrangement of one unit when the surface mount type MOSFET 21 is used. Also in this case, as in the case where the lead insertion type MOSFET 20 is used, the power supply line 59 which is a power supply connection portion and the connection line 60 are arranged without crossing each other.

  As described above, in each unit, the power supply line 59 and the connection line 60 are arranged on the circuit boards 401 and 411 without intersecting, so that the circuit pattern can be simplified.

  Further, since the power supply line 59 and the connection line 60 do not intersect with each other, it is easy to arrange the two MOSFETs 7 in one unit next to each other. In addition, since the MOSFETs 7 are easily distributed and arranged in pairs for each unit, the heat distribution of the radiator 8 is uniform.

  Further, since the power supply line 59 and the connection line 60 are not crossed, the three-phase inverter circuit 3 in which a large current may flow can be mounted on one surface of the circuit boards 401 and 411. Thus, when a double-sided mounting board is used as the circuit boards 401 and 411, the drive circuit 2 and the three-phase inverter circuit 3 can be separately mounted on both sides of the circuit boards 401 and 411, and the circuit reliability and the component mounting efficiency can be achieved. Will increase. Moreover, when a single-sided mounting board is used as the circuit boards 401 and 411, cost reduction can be achieved.

  Next, a second embodiment of the present invention will be described with reference to FIG. The same parts as those in the above-described embodiment are denoted by the same reference numerals and description thereof is omitted, and the drawings used in the above-described embodiment are also referred to as appropriate (the same applies to the following embodiments).

  FIG. 9 is a plan view showing the circuit board 201 of the present embodiment. The circuit board 201 is formed in a disk shape. The heat dissipating body 202 is formed in a circular ring shape, and is disposed horizontally with respect to the circuit board 201 outside the circuit board 201.

  The MOSFET 7 is a lead insertion type MOSFET 20, which is annularly disposed on the side edge of the circuit board 201 and is horizontally attached to the circuit board 201. The MOSFET 7 is fixed to the heat radiating body 202 with screws 9, and each terminal is connected on the mounting surface of the circuit board 201. At this time, the MOSFETs 7 constituting each unit are arranged so as to be adjacent to each other. Moreover, it arrange | positions at equal intervals for every 120 degree | times for every unit. In any one of the three-phase three-units, the MOSFET 7 is arranged opposite to the other two-unit MOSFET 7. In the present embodiment, as in the first embodiment, (MOSFET 7a on the U-phase upper arm 40 side, MOSFET 7b on the U-phase lower arm 41 side), (MOSFET 7d on the V-phase lower arm 41 side, V-phase upper arm) 40 side MOSFET 7c), (W-phase upper arm 40 side MOSFET 7e, W phase lower arm 41 side MOSFET 7f) in this order. That is, the V-phase MOSFET 7 is reversely arranged.

  The operation of the three-phase inverter circuit 3 at this time will be described with reference to FIG. Similarly to the first embodiment, in the section (1) in FIG. 5, the MOSFET 7a and the MOSFET 7d are energized. In the section (2), the MOSFET 7a and the MOSFET 7f are energized. In section (3), MOSFET 7c and MOSFET 7f are energized, in section (4) MOSFET 7c and MOSFET 7b, in section (5) MOSFET 7e and MOSFET 7b, and in section (6) MOSFET 7e and MOSFET 7d are energized. When the section (6) ends, the MOSFET 7a and the MOSFET 7d are energized again. One or more MOSFETs 7 that are not energized exist between the two MOSFETs 7 that are energized in any section. Therefore, similarly to the first embodiment, the temperature rise of the heat dissipating body 202 becomes uniform, thereby increasing the reliability of the circuit board 201.

  Further, in this embodiment, a circular circuit board 201 and a circular ring-shaped heat radiator 202 are used, and by using this structure, phase units are arranged at equal intervals from the centers of the circles of the circuit board 201 and the heat radiator 202. MOSFET7 is arrange | positioned for every. Thereby, the influence by the edge part of the thermal radiation body 202 can be eliminated. For this reason, when viewed from the heat dissipating body 202, the heat generation of all MOSFETs 7 can be considered under the same conditions. This facilitates the heat radiation design, reduces variations due to the temperature effect of the MOSFET 7, and leads to high reliability of the device.

  For example, when a three-phase brushless DC motor using a Y-connected or Δ-connected winding is used as the three-phase load 101, a rotating magnetic field is generated in the winding (three-phase load 101) by the above-described operation, and the motor is rotated. Let

  The present embodiment can be similarly implemented even if a surface mount type MOSFET 21 is used as the MOSFET 7 (not shown). In this case, as in the first embodiment, the heat dissipating body 202 also serves as the circuit board 201.

  In addition, the lead insertion type MOSFET 20 can be arranged upright with respect to the circuit board 201 (not shown). In this case, the radiator 202 may be a cylindrical member that surrounds the circuit board 201.

  Next, a third embodiment of the present invention will be described with reference to FIG. In the present embodiment, the arrangement of the MOSFET 7 is different from that of the second embodiment. In the second embodiment, three units of MOSFETs 7 are arranged at equal intervals one by one. However, in this embodiment, the MOSFETs 7 are arranged at three locations in a virtual quadrant division of the disc-shaped circuit board 301. Units are arranged. Further, the MOSFET 7 is a lead insertion type MOSFET 20 and is arranged in a ring shape on a side edge portion of the circuit board 301 for each unit. Here, in any one of the three-phase three-units, the arrangement of the MOSFETs 7 is opposite to the arrangement of the other two-unit MOSFETs 7. Here, the V-phase MOSFET 7 is reversely arranged. That is, (MOSFET 7a on the U-phase upper arm 40 side, MOSFET 7b on the U-phase lower arm 41 side), (MOSFET 7d on the V-phase lower arm 41 side, MOSFET 7c on the V-phase upper arm 40 side), (W-phase upper arm 40 side MOSFET 7c) The MOSFET 7e and the MOSFET 7f) on the W-phase lower arm 41 side are arranged in this order.

  With such a configuration, the MOSFETs 7 are arranged in phase units at substantially equal intervals from the centers of the circles of the circuit board 301 and the heat dissipating body 202, as in the second embodiment. And when MOSFET7 is driven by 120 degree | times electricity supply, the influence by the edge part of the thermal radiation body 202 can be decreased compared with 1st Embodiment, and it leads to the high reliability of an apparatus.

  For example, when a three-phase brushless DC motor using a Y-connected or Δ-connected winding is used as the three-phase load 101, a rotating magnetic field is generated in the winding (three-phase load 101) by the above-described operation, and the motor is rotated. Let

  Next, a fourth embodiment of the present invention will be described with reference to FIGS. FIG. 11 is a side view showing a part of the configuration of the electric blower 501 of the present embodiment. The electric blower 501 schematically includes a three-phase brushless DC motor 82, a centrifugal fan 84 attached to a rotor shaft 83 that is a rotating shaft of the three-phase brushless DC motor 82, and a structure that houses these. And a case 85. The case 85 includes a small-diameter motor case 86 that houses the three-phase brushless DC motor 82, a large-diameter fan cover 87 that houses the centrifugal fan 84, and a circular ring-shaped connecting portion that connects the motor case 86 and the fan cover 87. 88. The lower surface of the connecting portion 88 is formed in a planar shape.

  The three-phase brushless DC motor 82 includes a stator 89 fixed to a motor case 86 and a rotor 90 disposed inside the stator 89. A permanent magnet is used for the rotor 90. A rotor shaft 83 at the center of the rotor 90 is rotatably supported by bearing portions 91 provided on the upper and lower sides of the case 85. A blower outlet 92 as an exhaust outlet is formed on the side portion of the rear portion of the motor case 86. Further, the rear surface side of the motor case 86 in the axial direction is closed by the rear plate portion 93 in a bottomed shape, and the central portion of the rear plate portion 93 protrudes in a cylindrical shape toward the rear, where one bearing is provided. A portion 91 is provided.

  The three-phase brushless DC motor 82 requires magnet position detection means for the rotor 90. As such position detection means, three magnetic sensors installed at an electrical angle interval of 120 ° are used. Examples of the magnetic sensor include a hall sensor and a hall IC. As other permanent magnet position detection methods, a method using an optical pulse encoder, a method of detecting a voltage induced in the motor winding by a voltage phase detection means, although not particularly shown, can be used.

  A rectifying plate 94 is fixed to the lower side of the centrifugal fan 84. A fan cover 87 is attached so as to cover them. The fan cover 87 has a suction opening 95 at the center of the front surface, and the rear surface has a rear opening (not shown), and is formed in a substantially cylindrical shape as a whole.

  In such a configuration, when the rotor shaft 83 rotates, the centrifugal fan 84 rotates together with the rotation. By this rotation, the suction air passes through the centrifugal fan 84 from the suction opening 95 formed on the front side of the fan cover 87, is uniformly rectified by the rectifying plate 94, and is guided to the three-phase brushless DC motor 82. In this way, an air passage 96 extending from the suction opening 95 to the three-phase brushless DC motor 82 is formed.

  In the present embodiment, as shown in FIG. 12, the circuit board 601 that drives and controls the three-phase brushless DC motor 82 is located inside the case 85 and between the three-phase brushless DC motor 82 and the centrifugal fan 84. Is arranged. The circuit board 601 is basically the same as the circuit board 301 described in the third embodiment, but the shape of the circuit board 601 is different. The circuit board 601 is formed in a disc shape along the inner periphery of the connecting portion 88, and a pair of extending portions 602 are formed on the outer periphery of the disc shape. One extension portion 602 is connected to the plus side 100a of the DC power source 100 for supplying power to the circuit board 601 via the tab terminal 10a, and the other extension portion 602 is connected to the minus side of the DC power source 100. 100b is connected via the tab terminal 10a. A through hole 603 through which the rotor shaft 83 passes is formed at the center of the circuit board 601. A plurality of board air passage openings 604 for allowing air from the rectifying plate 94 to pass therethrough are formed around the through holes 603 in the circuit board 601. Here, the size and position of the board air passage port 604 are determined in the design of the electric blower 501.

  The MOSFET 7 mounted on the circuit board 601 is the lead insertion type MOSFET 20 as in the third embodiment, and their arrangement is the same as the circuit board 301. That is, the arrangement of the V-phase MOSFET 7 arranged between the U-phase and the W-phase is opposite to the arrangement of the U-phase and W-phase MOSFET 7. In the present embodiment, the six MOSFETs 7 are arranged on the outer surface (lower surface) of the connecting portion 88 and are fixed to the connecting portion 88 with screws 9. Here, the connecting portion 88 functions as the radiator 8.

  In the present embodiment, the three-phase inverter circuit 3 is provided on the board side edge 601a of the circuit board 601, and the drive circuit 2 is provided on the inner side. The power supply to the three-phase inverter circuit 3 is via a lead wire 605 connected to the positive side 100a of the DC power source 100 and a lead wire 605 connected to the negative side 100b of the DC power source 100 via the current detection resistor 42. Done.

  13 is a plan view showing the arrangement of the U-phase and W-phase MOSFETs 7, FIG. 14 is a plan view showing the arrangement of the V-phase MOSFET 7, and FIG. 15 is a perspective view showing an eyelet lug used for the power supply line 59.

  A plurality of connection terminals 70 which are thicker than the wiring pattern of the circuit board 601 and electrically insulated for each unit are used as terminals through which a large current flows in the circuit board 601. Here, the thickness of the wiring pattern of the circuit board 601 is about 35 μm to 70 μm, and the thickness of the connection terminal 70 is, for example, 0.5 mm. The terminals through which a large current flows are the drain terminal 31 on the upper arm 40 side, the source terminal 32 on the lower arm 41 side, the source terminal 32 on the upper arm 40 side, and the drain terminal 31 on the lower arm 41 side.

  In the drain terminal 31 or the source terminal 32 connected to the power supply line 59, for example, an eyelet lag shown in FIG. 15 can be used as the connection terminal 70. The eyelet lug is thicker than the wiring pattern and is fixed to the circuit board 601 by caulking. Further, the connection terminal 70 connected to the MOSFET 7 on the upper arm 40 side and the lower arm 41 side and connected to the three-phase brushless DC motor 82 is similarly thicker than the wiring pattern and fixed to the circuit board 601 by caulking. The connection terminal 70 is provided with a winding connection part 1000 protruding from the circuit board 601 because of the positional relationship between the winding and the circuit board 601 and the ease of connection.

  In the V phase opposite to the other two phases, the lead forming of the terminal of the MOSFET 7 constituting the upper arm 40 is different from that of the other MOSFET 7. That is, in the other two phases, the gate terminal 30 of the lower arm is positioned on the left side of the front, but in the V phase, it is reversed, so different lead forming is used. In the V phase, the shape of the connection terminal 70 connected to the winding is different from that in the U phase and the W phase.

  16 is a plan view showing the connection of the lead wire 605 in the U phase and the W phase, and FIG. 17 is a plan view showing the connection of the lead wire 605 in the V phase. As shown in FIGS. 16 and 17, the lead wire 605 is directly inserted and connected (brazed) to the eyelet lug fixed to the circuit board 601 by caulking.

  The direct current power source 100 connected to the positive side 100a and the negative side 100b of the direct current power source 100 is an assembled battery in which a plurality of secondary batteries such as a nickel cadmium (NiCd) battery, a nickel hydrogen battery, or a lithium ion battery are combined, or A commercial AC power supply is rectified and smoothed. This DC voltage is supplied to the circuit board 601.

  Next, the operation of the inverter circuit 3 when the MOSFET 7 is energized 120 degrees will be described. In the section (1) of FIG. 5, the MOSFET 7a on the U-phase upper arm 40 side and the MOSFET 7d on the V-phase lower arm 41 side operate. Thus, the current path from the positive side 100a of the DC power source 100 to the MOSFET 7a, the motor winding (not shown) outside the three-phase inverter circuit 3 and the MOSFET 7d, the current detection resistor 42, and the negative side 100b of the DC power source 100. Can do. At this time, in the MOSFET 7 shown in FIG. 12, the MOSFET 7a on the U-phase upper arm 40 side and the MOSFET 7d on the V-phase lower arm 41 side operate. Similarly, the MOSFET 7a and the MOSFET 7f operate in the section (2). Further, MOSFET 7c and MOSFET 7f operate in section (3), MOSFET 7c and MOSFET 7b operate in section (4), MOSFET 7e and MOSFET 7b operate in section (5), and MOSFET 7e and MOSFET 7d operate in section (6), respectively. When the section (6) ends, the MOSFET 7a and the MOSFET 7d operate again. Due to the operation of the inverter circuit 3, a rotating magnetic field is generated in the winding (three-phase load 101) of the three-phase brushless DC motor 82, and the rotor shaft 83 rotates. The centrifugal fan 84 is rotated by the rotation of the rotor shaft 83 and air is sucked from the suction opening 95. The sucked air is uniformly rectified and guided to the three-phase brushless DC motor 82.

  As described above, as in the above-described embodiment, there is no period in which the MOSFETs 7 arranged adjacent to each other on the substrate side edge 601a on the circuit board 601 are energized at the same time. There is a MOSFET 7 that is not energized. In the three-phase brushless DC motor 82 on which such a circuit board 601 is mounted, it is possible to avoid locally generating heat at the connecting portion 88 that is the radiator 8. Thereby, the temperature rise of the connection part 88 can be made uniform.

  In addition, since the MOSFET 7 is not disposed in the air passage 96 but is disposed in the connecting portion 88 which is a part of the case 85, the air flow inside the case 85 is not disturbed. Therefore, the heat generated by the MOSFET 7 can be released to the case 85 without increasing the air path loss of the electric blower 501 by the MOSFET 7.

  Since the circuit board 601 is formed with the board air passage opening 604, when the three-phase brushless DC motor 82 is operated, the air from the rectifying plate 94 passes through the board air passage opening 604 and reaches the three-phase brushless DC motor 82. The For this reason, it is possible to reduce the air path loss caused by arranging the circuit board 601 inside the case 85.

  In addition, at least a part of the outer periphery of the circuit board 601 is formed along the shape of the inner periphery of the case 85, and at least a part is accommodated in the case 85. Therefore, the circuit board 601 can be easily housed in the case 85, and the MOSFETs 7 serving as heating elements are all disposed in the connecting portion 88, so that the balance of heat generation and the ease of housing the circuit board 601 are achieved. it can. Furthermore, since the heat radiator 8 is a case 85 (specifically, a connecting portion 88) that is a structure constituting the three-phase brushless DC motor 82, the components can be effectively used. From this, it can contribute to the miniaturization of the three-phase brushless DC motor 82 together with heat generation countermeasures.

  The current density can be reduced by providing the connection terminals 70 that are formed thicker than the wiring pattern formed on the circuit board 601 and are provided on the circuit board 601. Thereby, the safety | security of the circuit board 601 can be improved.

  Further, a part of the power supply line 59 is constituted by the lead wire 605, and the lead wire 605 is directly inserted into the eyelet lug, so that it is not necessary to arrange the power supply pattern on the circuit board 601. This leads to high output of the electric blower 501 by increasing the current.

  In this embodiment, the circuit board 601 is described as an example of the circuit board. However, the present invention is not limited to this, and the circuit boards 1, 201, 301, 401, and 411 may be used.

  In the above embodiment, the MOSFET 7 is used as the power device. However, the present invention is not limited to this, and any power device having one control terminal and two controlled terminals may be used. Can be implemented. For example, switching elements such as bipolar transistors and IGBTs (Insurated Gate Bipolar Transistors) are also applicable.

1 is an external perspective view showing a circuit board according to a first embodiment of the present invention. It is an external appearance perspective view which shows the circuit board of another example. It is a front view showing terminal arrangement in a lead insertion type MOSFET and a surface mount type MOSFET. It is a circuit diagram which shows the schematic circuit structure of a drive circuit and a three-phase inverter circuit. It is a time chart of the signal output to the gate terminal of MOSFET by a 120 degree | times electricity supply system. It is a perspective view which shows the lead forming of lead insertion type MOSFET. It is a perspective view which shows the surface wiring pattern with respect to MOSFET in a circuit board. It is a top view which shows arrangement | positioning of MOSFET for one phase when surface mount type MOSFET is employ | adopted. It is a top view which shows the circuit board of the 2nd Embodiment of this invention. It is a top view which shows the circuit board of the 3rd Embodiment of this invention. It is a side view which partially cuts and shows the structure of the electric blower of the 4th Embodiment of this invention. It is a top view which shows a circuit board. It is a top view which shows arrangement | positioning of MOSFET of U phase and W phase. It is a top view which shows arrangement | positioning of V-phase MOSFET. It is a perspective view which shows an eyelet lag. It is a top view which shows the connection of the lead wire in U phase and W phase. It is a top view which shows the connection of the lead wire in V phase.

Explanation of symbols

1 Circuit board 3 Three-phase inverter circuit 7 MOSFET (power device)
8 Radiator 40 Upper arm 41 Lower arm 59 Power line (power connection)
60 Connection line (connection part)
70 Connection terminal 82 Three-phase brushless DC motor 85 Case (structure)
100 DC power supply
201 circuit board 202 radiator 301 circuit board 401 circuit board 411 circuit board 501 electric blower 601 circuit board 605 lead wire

Claims (6)

A three-phase inverter circuit that has a plurality of power devices that are mounted on a radiator and constitutes an upper arm and a plurality of power devices that constitute a lower arm, and these power devices are driven by a 120-degree conduction method. In the mounted circuit board,
Among the power devices, the upper arm power device constituting the same phase and the lower arm power device are paired and arranged so as to be adjacent to each other,
The power device on the upper arm side and the power device on the lower arm side in the phase located in the center of the three phases are arranged in the order of the power device on the upper arm side and the lower arm side in the other two phases. The circuit board is reverse to the arrangement order of the power devices.   Among the power devices, an upper arm power device that constitutes the same phase and a lower arm power device that are paired with each other are arranged on the heat sink in a ring shape so as to be adjacent to each other. The circuit board according to claim 1.   Among the power devices to be paired, the power devices constituting the phases whose order is not reversed are arranged on the circuit board so that the control terminals on the lower arm side of the paired power devices are located outside. The circuit board according to claim 1, wherein the circuit board is provided. A three-phase brushless DC motor;
The circuit board according to any one of claims 1 to 3, which controls the driving of the three-phase brushless DC motor;
An electric blower comprising: A case constituting the brushless DC motor;
At least a part of the circuit board is housed in the case,
The electric blower according to claim 4, wherein at least a part of an outer periphery of the circuit board housed in the case is formed along an inner peripheral shape of the case. The power device is a lead insertion type,
The intervals adjacent to each other of the power devices to be paired are substantially equal intervals,
The electric blower according to claim 4 or 5, wherein the heat dissipating body is a structure constituting the brushless DC motor.

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