JPH11340389A - Electronic unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a radiation property, and to easily remove a heat sink on disassembly. SOLUTION: At the upper-surface part of an IPM 12 (intelligent power module) that has an inverter circuit and a predrive circuit integrally, a screw 25 is clamped from a lower-surface side for mounting a heat sink 24. The IPM 12 is soldered for mounting by inserting each lead 12a into the through hole of a circuit board 21. At this time, a hole 21a corresponding to the mounting position of the screw 25 is formed on the circuit board 21. The circuit board 21 is accommodated into a case 23, and a potting material 26 is filled so that the entire lead 12a of the IPM 12 is buried. On disassembly, the bottom-wall part of the case 23 is broken by a drill or the like, a driver is inserted from a lower part through a hole 21a of the circuit board 21, and the screw 25 is loosened, then the heat sink 24 can be removed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an IPM used for, for example, an inverter-driven washing machine motor drive device.
The present invention relates to an electronic unit having an intelligent power module mounted on a circuit board.

[0002]

In recent years, for example, an inverter-driven three-phase brushless motor has been used as a motor for directly driving a rotary tub and a stirring body in a washing machine. In this case, the motor driving device includes an inverter circuit including a plurality of switching elements such as an IGBT, a pre-drive circuit that drives the switching elements, and the like. Such a motor drive device is configured by mounting each component on a circuit board, housed in a case and unitized, subjected to potting with a moisture proof material, for example, in the upper part of the washing machine main body. It is arranged inside the top cover.

At this time, in order to dissipate the heat of the switching elements, a heat radiating plate made of aluminum is attached to the upper surface of the switching elements while being exposed from the moisture-proof material. However, in the conventional configuration, in order to obtain good heat radiation from all the switching elements, there is a problem that the heat radiation plate is enlarged (the area in the plane direction is increased).

[0004] When the above-mentioned electronic unit is discarded, it is necessary to remove the aluminum radiator plate for recycling in order to recycle the electronic unit. However, the conventional electronic unit does not have a configuration in which the removal of the heat sink during disassembly is taken into consideration, and the removal of the heat sink requires a considerably troublesome operation.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electronic unit that is excellent in heat dissipation of an element and that can easily remove a heat sink during disassembly.

[0006]

For example, in recent years, as a motor drive device, an IPM incorporating an inverter circuit, a pre-drive circuit for driving the inverter circuit, a protection circuit against overcurrent and temperature of the inverter circuit, etc. as one module has been recently developed.
(Intelligent Power Module) is being developed. The present inventors have focused on such an IPM,
In an electronic unit with a PM, in addition to the original effects of the IPM such as compactness and good assemblability to a circuit board, the heat dissipation of the elements constituting the IPM is improved and The present invention has been accomplished in order to obtain a configuration that facilitates removal.

That is, an electronic unit according to a first aspect of the present invention is for accommodating a circuit board on which a lead-attached IPM is mounted in a case, and the IPM is mounted on an upper surface of the IPM.
Attach a heat sink from the lower surface side of the M with a fixture such as a screw, form a hole in the circuit board corresponding to the mounting position of the fixture, and further potting in the case to cover the circuit board and the IPM leads. It is characterized by a structure filled with materials.

According to this, heat is radiated from the heat radiating plate attached to the upper surface of the IPM, and the heat transmitted to the lead portion of the IPM is transmitted from the case via the potting material or the circuit board and the potting material. Heat is dissipated. At this time, between the IPM lead and the case inner surface,
Because a potting material with a large heat capacity is interposed,
Better heat conduction to the case than when an air layer is interposed.

The radiator plate is attached from the lower surface side of the IPM with a fixture such as a screw, and a hole corresponding to the fixture is formed in the circuit board, so that the outer wall of the case is broken. Thereby, the mounting fixture can be easily removed through the hole of the circuit board, and the heat sink can be easily separated. By using the IPM, the mounting area can be reduced, the circuit board and the whole can be reduced in size, and the assembling work can be easily performed and the heat sink can be reduced in size. .

In this case, a part of the heat radiating plate may be buried in a potting material.
Invention). According to this, a heat dissipation path is provided in which heat of the heat dissipation plate is transmitted to the case via the potting material and dissipated, and even when heat dissipation from the heat dissipation plate to the outside air is not sufficiently performed, Heat can be dissipated effectively.

Further, the IPM may be mounted so as to be lifted from the upper surface of the circuit board, and another component may be mounted on the circuit board located between the circuit board and the IPM. Item 3), whereby the mounting density can be further improved by effectively utilizing the area of the circuit board.

Further, it is effective if a mark for indicating the position of a hole formed in the circuit board is provided on the outer surface of the case (the invention of claim 4). According to this, at the time of disassembly, the portion indicated by the mark in the case is destroyed, so that the attachment can be more easily removed.

In this case, if a portion of the case corresponding to the hole formed in the circuit board is formed in a thin shape.
Invention), the destruction work of the case at the time of disassembly becomes easier. Further, the case may be provided with a support portion for supporting a heat sink (the invention of claim 6).
Thus, the heat sink can be supported by the case, so that the stress acting on the connection portion of the IPM lead to the circuit board can be reduced.

Further, a second heat radiating plate can be provided on the lower surface side of the IPM (the invention of claim 7), whereby the heat radiating property can be further improved. At this time, a part of the second radiator plate may be provided in a form exposed from the potting material on the upper surface (the invention of claim 8), whereby the heat of the second radiator plate is radiated to the outside air. It is possible to improve the heat radiation.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Several embodiments in which the present invention is applied to a control electronic unit of a fully automatic washing machine will be described below with reference to the drawings. (1) First Embodiment First, a first embodiment (corresponding to claim 1) of the present invention will be described with reference to FIGS.

FIG. 2 shows an electrical configuration of the fully automatic washing machine according to the present embodiment.
Although not shown in detail, this washing machine has a load
A rotating tub provided in the outer tub, a washing machine motor 1 for rotatingly driving a stirring body provided in the rotating tub, a water supply valve 2 for supplying water to the rotating tub, and a flexible finish in the rotating tub. A softer valve 3 for automatically charging the agent, a drain valve 4 for draining water from the rotary tank, a pump 5 for supplying bath water and the like to the rotary tank, and the like are provided.

In this case, the washing machine motor 1 is composed of an inverter-driven brushless motor having three-phase windings, and is controlled by a control microcomputer 6 for controlling the entire washing operation.
Drive control is performed via a motor drive device 7 described later. The water supply valve 2, the softer valve 3, the drain valve 4, and the pump 5 are also controlled by the control microcomputer 6 via a driver 8 and an AC drive element 9 to cut off or turn off the power. Further, the control microcomputer 6 includes:
The key input signal of the operation panel 10 provided on the upper surface of the top cover is input, and the control microcomputer 6 controls the display of the operation panel 10.

The motor driving device 7 includes a power supply circuit 11 and an intelligent power module (IPM) 12. The power supply circuit 11 has a well-known configuration including a rectifier circuit 14 for full-wave rectification of the commercial AC power supply 13, a smoothing capacitor 15, a DC / DC converter 16, and the like, and supplies DC power to the inverter circuit 17 of the IPM 12. Has become.

The IPM 12 includes six switching elements (IGBTs) 18 and the like connected in a three-phase bridge. The inverter circuit 17 supplies current to the washing machine motor 1. A pre-drive circuit 19 for driving the gate, a protection circuit against overcurrent and temperature of the inverter circuit 17 and the like are incorporated as one module. In this case, as shown in FIG. 1, the IPM 12 is a DIP-type component in which a large number of leads 12a are led out from two sides of a rectangular package.

The control microcomputer 6 supplies an energization signal to the pre-drive circuit 19 of the IPM 12, and the pre-drive circuit 19 controls the switching element 18 of the inverter circuit 17 based on the energization signal. The washing machine motor 1 is driven by the three-phase AC output from the motor 17. At this time, the control microcomputer 6 receives a rotation signal of the motor 1 from a rotation position detector 20 that detects the rotation position of the washing machine motor 1.

The above-described motor driving device 7 is configured as an electronic unit 23 in which each component is mounted on a circuit board 21 made of a printed wiring board and the circuit board 21 is housed in a case 22. In such a state, it is arranged in a top cover (not shown) of the washing machine. Hereinafter, the electronic unit 23 according to the present embodiment will be described with reference to FIG.

FIG. 1 is a block diagram of the electronic unit
3 shows a cross section of a mounting portion of M12. Where IPM
A radiator plate 24 is mounted on the upper surface of the package 12. The heat radiating plate 24 is made of, for example, aluminum and has a comb-shaped heat radiating fin on the upper surface of a main plate portion that is in close contact with the IPM 12. At this time, a screw insertion hole 12b is provided vertically in the center of the package of the IPM 12, and a screw hole 24a is formed at a position corresponding to the screw insertion hole 12b. Is to fix the screw 25
The screw hole 2 is inserted through the screw insertion hole 12b from the lower surface side of the M12.
4a.

The IPM 12 is provided with through-holes (not shown) formed in the circuit board 21 with respective leads 12a.
Is inserted, and each lead 12a is mounted on the lower surface of the circuit board 21 by soldering. At this time, the IPM 12 is arranged so as to slightly float from the upper surface of the circuit board 21. A hole 21a is formed in the circuit board 21 at a position where the screw 25 is mounted.

The case 22 is in the form of a thin rectangular box with an open top in the figure made of plastic, and the circuit board 21 is housed and mounted inside the box. The case 22 has a moisture-proof property, an insulating property,
To improve the mechanical strength, a potting material 26 made of, for example, urethane resin is filled. In this embodiment, the potting material 26 is filled up to a height position (the height of the lower surface of the heat sink 24) at which the entire lead 12a of the IPM 12 is buried.

Next, the operation of the above configuration will be described. In the electronic unit 23 described above, the motor driving device 7
Circuit 17 and pre-drive circuit 1 constituting
Since the IPM 12 in which the switching elements 9 and the like are modularized into one is adopted, unlike the conventional one in which the switching elements and the like are individually mounted on the circuit board, the assemblability to the circuit board 21 is facilitated, 21 and the whole (Case 2
2) It is possible to reduce the size of the heat sink 24 and the like.

In this configuration, the IPM12
Is transmitted to the heat radiating plate 24 attached to the upper surface thereof, and the heat is radiated from the heat radiating plate 24 to the outside air, and a part of the heat of the IPM 12 is transmitted from the lower surface side of the IPM 12 and the lead 12a. Then, the heat is transmitted to the case 22 via the potting material 26 or the circuit board 21 and the potting material 26, and the heat is radiated from the case 22. At this time, since the potting material 26 has a larger heat capacity than the air layer, better heat conduction to the case 22 is performed as compared with the case where the air layer is interposed between the IPM 12 and the case 22, and excellent heat dissipation is achieved. Can be obtained.

When the electronic unit 23 (washing machine) is discarded, it is disassembled and recyclable, and is separated and collected. The aluminum radiator plate 24 is taken out and provided for separation and collection. At this time, in this embodiment,
A radiator plate 24 is attached from the lower surface side of the IPM 12 by screws 25, and the circuit board 21 has the screws 25.
Is formed, the case 21 is formed.
Is broken by a drill or the like, a screwdriver is inserted through the hole 21a of the circuit board 21 from below, and the screws 25 are loosened, so that the heat sink 24 can be easily removed.

As described above, according to the present embodiment, the IPM 12
, The mounting area can be reduced, the circuit board 21 and the whole (the case 22) can be made compact, the assembling work is easy, and the heat radiating plate 24 can be small. Of course, and the circuit board 21 and the leads 12a of the IPM 12 are obtained.
Since the portion was covered with the potting material 26,
An excellent practical effect that good heat radiation properties can be obtained and that the work of removing the heat radiating plate 24 at the time of disposal can be easily performed can be obtained.

(2) Second to Seventh Embodiments Next, second to seventh embodiments of the present invention will be described with reference to FIGS. In addition, these 2nd-7th
Each embodiment of the present invention can be said to be a modification of the above-described first embodiment, and the same portions as those of the above-described first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. Only the part that becomes

FIG. 3 shows a second embodiment of the present invention.
2 shows a configuration of the electronic unit 31 according to the first embodiment.
In this embodiment, the heat sink 32 attached to the upper surface of the IPM 12 has a protrusion 3 extending downward at its end.
2a. And in the case 22,
For example, a potting material 33 made of urethane resin is filled. The potting material 33 has the protrusions 32 buried therein and a part of the main plate of the heat sink 32 (substantially the lower half in the thickness direction). Are provided up to a height position where the embedded state is established.

According to such a configuration, as in the first embodiment, good heat radiation of the IPM 12 can be obtained, and the work of removing the heat radiation plate 32 at the time of disposal can be easily performed. Not only has the effect of being able to
The heat of the heat sink 32 is transferred to the case 2 via the potting material 33.
2 is also provided, so that even when the heat radiation from the heat radiating plate 32 to the outside air is not sufficiently performed, the heat can be effectively released. Can be.

FIG. 4 shows a third embodiment of the present invention.
2 shows a configuration of the electronic unit 41 according to the first embodiment.
The difference between this embodiment and the first embodiment is that a gap between the lower surface of the IPM 12 on the circuit board 21 and
The other point is that another component 42 (for example, a chip-type resistor or the like) constituting the motor driving device 7 is mounted. According to this, in addition to the actions and effects similar to those of the first embodiment,
The effect that the mounting density can be further improved by effectively utilizing the area of the circuit board 21 can be obtained.

FIG. 5 shows the structure of an electronic unit 51 according to a fourth embodiment (corresponding to claims 4 and 5) of the present invention. In this embodiment, a convex portion 53 is formed on the bottom wall of the case 52 so as to correspond to the position where the hole 21a of the circuit board 21 is formed and serves as a mark indicating the position of the hole 21a. Have been. Further, here, the convex portion 53 is configured to be thinner than the thickness of other portions of the case 52.

According to this, the position of the bottom wall of the case 52 corresponding to the hole 21a of the circuit board 21 can be easily determined by the projection 53, so that when disassembling (when removing the heat sink 24), The operator only has to break the protruding portion 53 with a drill or the like without destroying the extra portion, and can easily perform the work. Further, since the portion to be broken is thin, This operation can be performed even more easily.

FIG. 6 shows a fifth embodiment of the present invention.
2 shows a configuration of an electronic unit 61 according to the first embodiment.
In this embodiment, a fitting piece portion 62a extending so as to protrude inward and functioning as a support portion is provided above the left and right inner wall portions of the case 62 in the drawing. In the left and right side walls in the drawing of the heat radiating plate 63, fitting recesses 63a into which the tips of the fitting pieces 62a fit are formed.

In this case, when fitting the fitting recess 63a of the heat sink 63 to the fitting piece 62a, the case 62
In this figure, the heat radiating plate 63 (circuit board 21) may be fitted while the left and right walls are temporarily bent outward. As a result, the heat radiating plate 63 can be supported by the case 62, so that the circuit board 21 of the lead 12 a of the IPM 12 can be used.
Therefore, there is an advantage that the stress acting on the connection portion (soldering portion) can be reduced.

FIG. 7 shows a sixth embodiment of the present invention.
2 shows a configuration of an electronic unit 71 according to the first embodiment.
In this embodiment, a second heat radiating plate 72 made of, for example, aluminum and having a plate shape is provided on the lower surface of the IPM 12. At this time, the second
The heat radiating plate 72 and the heat radiating plate 24 are one screw 7
3, they are fastened from the bottom so to speak. According to this, the heat is radiated from the second heat radiating plate 72 having good thermal conductivity via the potting material 26, so that the heat radiating property can be further improved.

FIG. 8 shows a seventh embodiment of the present invention.
2 shows a configuration of an electronic unit 81 according to the first embodiment.
In this embodiment, similar to the sixth embodiment, the IPM1
The second heat radiating plate 82 is provided on the lower surface of the second heat radiating plate 2. At this time, the second heat radiating plate 82 is integrally provided with a protruding portion 82a extending upward from a portion having no lead 12a. The upper end of the projection 82a is exposed from the potting material 26 to the upper surface.
Thus, the heat of the second heat radiating plate 82 can be radiated to the outside air, and the heat radiation can be further improved.

In each of the above embodiments, the screws 25 and 73 are used as attachments for attaching the heat sink, but they may be attached by caulking using rivets or the like. Further, the heat radiating plate 24 may not be in contact with the potting material 26. Further, in the fourth embodiment, the convex portion 53 is formed on the case 52 as a mark. However, the mark may be a concave portion, and a mark may be simply formed on the bottom surface of the case by printing or the like. May be.

In addition, the present invention is not limited to the embodiments described above and shown in the drawings. For example, it is needless to say that the above-described embodiments may be appropriately combined with each other. The present invention is not limited to the motor drive device of the washing machine, but can be applied to any electronic unit employing the IPM, and can be appropriately modified and implemented without departing from the gist thereof.

[0041]

As is apparent from the above description, according to the electronic unit of the present invention, the heat radiating plate is attached to the upper surface of the IPM from the lower surface side of the IPM by a mounting tool such as a screw, and is attached to the circuit board. Holes are formed corresponding to the mounting position of the mounting fixture, and the case is filled with a potting material so as to cover the circuit board and IPM leads. This has an excellent effect that removal can be easily performed.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of the present invention, and is a longitudinal sectional view of an IPM mounting portion of an electronic unit.

FIG. 2 is a diagram showing an electrical configuration of the washing machine.

FIG. 3 is a view corresponding to FIG. 1, showing a second embodiment of the present invention;

FIG. 4 is a view corresponding to FIG. 1, showing a third embodiment of the present invention;

FIG. 5 is a view corresponding to FIG. 1, showing a fourth embodiment of the present invention.

FIG. 6 is a view corresponding to FIG. 1, showing a fifth embodiment of the present invention.

FIG. 7 is a view corresponding to FIG. 1, showing a sixth embodiment of the present invention;

FIG. 8 is a view corresponding to FIG. 1, showing a seventh embodiment of the present invention.

[Description of References] In the drawings, 1 is a washing machine motor, 7 is a motor driving device, 12
Is an IPM, 12a is a lead, 17 is an inverter circuit, 1
9 is a pre-drive circuit, 21 is a circuit board, 21a is a hole,
22, 52, 62 are cases, 23, 31, 41, 51,
61, 71, 81 are electronic units, 24, 32, 63 are heat sinks, 25, 71 are screws (attachments), 26, 33 are potting materials, 42 is components, 53 is protrusions (marks), 6
2a is a fitting piece (supporting portion), and 72 and 82 are second heat radiating plates.

Claims (8)

[Claims] 1. A case, a circuit board housed in the case, a lead-attached IPM mounted on the circuit board, and mounting of screws or the like on an upper surface of the IPM from a lower surface of the IPM. A heat sink attached by a tool, a hole formed in the circuit board corresponding to a mounting position of the fixture, and a potting material filled in the case so as to cover the circuit board and the leads of the IPM. An electronic unit comprising: 2. The electronic unit according to claim 1, wherein a part of the heat radiating plate is buried in the potting material. 3. The IPM is mounted in a state of being lifted from the upper surface of the circuit board, and components are mounted on the circuit board between the circuit board and the IPM. Item 3. The electronic unit according to Item 1 or 2. 4. The electronic unit according to claim 1, wherein a mark for indicating a position of a hole formed in the circuit board is provided on an outer surface portion of the case. 5. The electronic unit according to claim 1, wherein a portion of the case corresponding to the hole formed in the circuit board is formed in a thin shape. 6. The case according to claim 1, wherein a support portion for supporting the heat sink is provided on the case.
Electronic unit according to any one of the above. 7. The electronic unit according to claim 1, wherein a second heat sink is provided on a lower surface side of the IPM. 8. The electronic unit according to claim 7, wherein the second heat radiating plate is provided such that a part thereof is exposed from a potting material to an upper surface.