JP2002199740A - Inverter unit and product using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inverter unit and a product using it, that enables it to turn compact in size and low in cost. SOLUTION: This inverter unit is provided with a main board 13, which is structured by mounting an inverter circuit provided with rectifying/smoothing circuits and switching elements on a board on which wiring circuits are formed by covering and forming circuit patterns of conductive plates with insulating resin, a sub-board 14 on which a control circuit that controls the inverter circuit is mounted, and a baseboard 12 on which other circuits are mounted. The main board 13 and the sub-board 14 are assembled on the baseboard 12 and jointed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooking device such as a microwave oven for heating food with microwaves, a lighting device for lighting an electrodeless arc tube with microwaves, and other power circuits for IH cooking devices, air conditioners, refrigerators and the like. And a product using the same.

[0002]

2. Description of the Related Art Conventionally, for example, in a microwave oven 31, as shown in FIGS. 8 and 9, an inverter unit 32 constituted by mounting all components on one substrate 33, a magnetron 34 , Cooling fans 35 and 36 are individually arranged on the bottom plate 37. Then, a voltage of 4000 V DC generated by the inverter unit 33 is applied to the magnetron 34 via the high voltage line 38, and the voltage of 2450 MHz
, And is guided to the interior space 39 through a waveguide (not shown) to heat the food. Since the inverter unit 32 generates about 100 W of heat, it is cooled by the cooling fan 35.

In addition, instead of mounting all the components on one substrate, the components are divided into a plurality of substrates and mounted, and these substrates and radiation fins are assembled in one case to form a three-dimensional structure. By placing them together and connecting the boards,
Inverter units having a compact configuration are also known.

[0004]

By the way, the inverter unit is required to be further reduced in size and cost. On a general board such as a paper phenol board, a circuit pattern such as a thin copper foil is formed on the surface thereof. In circuits that handle high voltages and large currents, it is necessary to increase the conductor width of the pattern to secure the required conductor cross-sectional area and increase the spacing between patterns to ensure the required insulation performance. However, there is a problem that the size of the substrate becomes large and the size of the inverter unit cannot be reduced.

[0005] On the other hand, a printed circuit board formed by coating a plate-shaped circuit pattern of copper or other conductive metal with an insulating resin and allowing a high voltage and a large current to flow in a compact configuration is a paper phenol board or the like. The price is ten times or more higher than a commonly used substrate, which is very expensive. Therefore, when the substrate 33 of the conventional inverter unit 32 shown in FIGS. 8 and 9 and a plurality of substrates to be assembled in the case are constituted by such a wiring circuit molded substrate,
There is a problem that the cost increases.

When a plurality of substrates are used, since the substrates are connected to each other by a connector, there is a problem that the cost of parts is increased, the number of assembling steps is increased, and the cost is increased.

The present invention has been made in consideration of the above-described conventional problems, and has as its object to provide an inverter unit that can be reduced in size and cost and a product using the inverter unit.

[0008]

According to the present invention, there is provided an inverter unit in which at least a part of a component for handling a high voltage and a large current is formed by forming a circuit pattern formed of a conductive plate with an insulating resin. The main board mounted on the board and the board mounted with other components are combined and joined, and the main board mounting at least a part of the components handling high voltage and large current can be downsized. In addition, the main board is combined with a board on which other components are mounted and joined, so that it can be made compact.In addition, the board other than the main board can be made inexpensive by using a general cheap board such as a paper phenol board. , And can be reduced in size and cost.

[0009] Further, a main board in which an inverter circuit having a rectifying / smoothing circuit and a switching element is mounted on a printed circuit board formed by covering a circuit pattern made of a conductive plate with an insulating resin and controlling the inverter circuit. A sub-board on which a control circuit is mounted and a base board on which other circuits are mounted are provided.If the main board and sub-board are assembled and joined to the base board, the inverter circuit can be modularized as a compact main board, and Various target products can be used in common and shared, cost reduction can be realized by taking advantage of the mass merits, and since the main board and sub-board of the control circuit are assembled on the base board, it can be configured more compactly and downsized. The price can be reduced.

Further, when the main substrate and the sub-substrate are vertically joined to the base substrate, a three-dimensional combination can be achieved to further reduce the size and to make contact with the inverter circuit mounted on the main substrate. By disposing a cooling plate, the inverter circuit that generates heat can be cooled efficiently in a compact manner, and when the cooling plate is configured with a cover, no additional cooling fins are required, making it more compact and lower cost. Can be achieved.

When a plurality of main boards are provided, independent control becomes possible by providing a plurality of inverter circuits, which is useful for a rice cooker, a three-phase motor, and the like.

When a sub-substrate on which components of a circuit for extending the function of the inverter circuit are mounted is provided, for example, by adding a clamp circuit as an extended function, voltage control becomes possible, and inexpensive switching with low withstand voltage is achieved. Various additional effects such as the use of an element can be obtained.

When the main board and the sub-board are joined to each other by a lead frame perpendicular to both boards, to each other by a wiring board, or to each other by a film-like wiring board, a three-dimensional structure is obtained. The inverter circuit can be arbitrarily controlled by transmitting the drive signal of the switching element, the current value monitor signal of the inverter circuit, and supplying the AC power. .

Further, the product of the present invention is provided with the above-mentioned inverter unit in a power circuit, and the above-described effects can be obtained, and the size of the product can be reduced.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an inverter unit according to an embodiment of the present invention and a microwave oven using the same will be described.
This will be described with reference to FIGS.

(First Embodiment) First, a first embodiment will be described with reference to FIGS. In FIG. 1, reference numeral 1 denotes a microwave oven as an example of a product, reference numeral 2 denotes a space inside the refrigerator, reference numeral 3 denotes a front opening / closing door, and reference numeral 4 denotes an operation unit at a lower front portion. Reference numeral 5 denotes a microwave generator arranged on the back surface, which is composed of an inverter unit 6, a cooling fan 7, and a magnetron 8.

As shown in FIG. 2, the microwave generator 5 includes a case 9 having a shallow dish-shaped case main body 10 and a cover 11 formed by forming a metal plate into a U-shape in cross section so as to cover an upper part thereof. The base board 12 of the inverter unit 6 is provided on the bottom of the case body 10 over substantially the entire length thereof, and the cooling fan 7 and the magnetron 8 are provided on the base board 12. .

As shown in FIGS. 2 and 3, the inverter unit 6 is formed by joining the base substrate 12, a main substrate 13 formed of a printed circuit board, and a sub-substrate 14 formed of a paper phenol substrate. I have. Reference numeral 15 denotes a film-shaped wiring board for connecting the main board 13 and the sub-board 14, on which electronic components are mounted.

As shown in FIG.
An inverter circuit 17 including a smoothing circuit 16 and a switching element, and a drive circuit 18 thereof are mounted. Since the rectifying element and the switching element generate a large amount of heat and have a high current / voltage value flowing through the wiring, the main substrate 13 is formed by a wiring circuit molded substrate in which a circuit pattern formed of a conductive plate is coated with an insulating resin. We are trying to make it more compact.
On the sub-board 14, a control circuit 19 that performs functions such as outputting a drive signal and monitoring an inverter circuit is mounted.
Since the control current only flows, it is composed of an inexpensive paper phenol substrate. A high-voltage transformer 20 and a voltage doubler circuit 21 are mounted on the base substrate 12, and connection terminals for the outside of the inverter unit are formed. In the present embodiment, the base substrate 12 is formed of a paper phenol substrate, but is not limited thereto, and may be formed of a glass epoxy substrate or an alumina substrate as necessary.

The main substrate 13 and the sub-substrate 14 are joined to the base substrate 12 by inserting leads extending from edges of the main substrate 13 and the sub-substrate 14 into connection holes formed in the base substrate 12 and soldering. The mechanical connection is performed simultaneously with the electrical connection.

Since the switching elements forming the inverter circuit 17 mounted on the main board 13 generate a large amount of heat as described above, the inverter circuit 17 is connected to the upper end of the main board 13 as shown in FIGS. Is mounted on the inverter circuit 17 in a vertical posture (horizontal posture).
1 are brought into contact with each other so that the cover 11 functions as a cooling plate. Thus, the inverter circuit 17 that generates heat can be efficiently cooled with a compact configuration, and a separate cooling fin is not required, so that the size and cost can be further reduced.

FIG. 5 shows an example of a circuit diagram of the rectifying / smoothing circuit 16 and the inverter circuit 17. IN1 and IN2 are input terminals of an AC power supply, DR is a drive signal input terminal for switching, OUT1 and OUT2 are output terminals to the high-voltage transformer 20 after switching, and C1 to C6 are rectification / smoothing circuits 16
And a terminal for monitoring the operation state of the inverter circuit 17. This basic circuit is common to the inverter unit and can be shared and used for a microwave oven, a rice cooker, a cooker, and the like.

When the base substrate 12, the main substrate 13 and the sub-substrate 14 are three-dimensionally arranged as described above, the wiring between the main substrate 13 and the sub-substrate 14 tends to be long,
Since the switching timing is important in the inverter circuit 17, the wiring must be shortened. Therefore, in the present embodiment, the main board 13 on which the inverter circuit 17 is mounted and the sub-board 14 on which the control circuit 19 is mounted are three-dimensionally connected by the wiring board 15 made of a polyimide film. Electronic components can be mounted on the wiring board 15 as needed. Further, the cost can be reduced by using PET as the film material. If mechanical strength is required, it may be joined with a wiring board such as a lead frame or a paper phenol board.

According to this embodiment, since the inverter unit 6 is three-dimensionally constructed as described above, the size can be reduced. As shown in FIG. A microwave generator 5 comprising a cooling fan 7 and a magnetron 8 can be provided. Compared with a conventional example in which an inverter unit is provided at the bottom as shown in FIG. In particular, the height dimension H can be made significantly smaller than the conventional example H ₀ .

The present invention can be applied not only to the microwave oven of the above embodiment but also to products such as a rice cooker, an electromagnetic cooker, an air conditioner, and a motor, and these products can be downsized.

(Second Embodiment) Next, a second embodiment will be described with reference to FIGS. The same components as those described in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. Only different points will be mainly described.

In FIG. 6, 12 is a base board, 13 is a main board on which an inverter circuit 17 is mounted, 14 is a sub-board on which a control circuit is mounted, and 15 is a film-shaped wiring board for connecting the main board 13 and the sub-board 14. Reference numeral 23 denotes a sub-board for extending the function of the inverter circuit 17. Sub-board 2
The components other than 3 are configured similarly to the first embodiment. The sub-board 23 is an additional module for adding a circuit required for the target inverter unit 6. For example, when it is necessary to regulate the upper and lower limits of the inverter output voltage, a clamp circuit 24 as shown in FIG. When a plurality of switching circuits are required, a switching circuit 25 as shown in FIG. 7B is mounted and connected.

In the inverter unit of the present embodiment, functions can be added by the sub-board 23, and since the inverter unit is three-dimensionally formed, the size can be reduced as compared with the conventional one.

[0029]

According to the inverter unit and the product using the same according to the present invention, at least a part of the components handling the high voltage and the large current as described above is formed by connecting the circuit pattern formed of the conductive plate to the insulating resin. The main board mounted on the wiring circuit molded board covered with the above is combined with the board mounted with other components, so that the main board can be downsized and the main board mounted with other components Inverter unit can be made compact because it is combined with other components, and the board other than the main board can be made cheap by using a general cheap board such as a paper phenol board. realizable.

[Brief description of the drawings]

FIG. 1 is a perspective view of a microwave oven to which an inverter unit according to a first embodiment of the present invention is applied.

FIG. 2 is a cross-sectional view of the microwave generator in the microwave oven of the embodiment.

FIG. 3 is a perspective view of the inverter unit of the embodiment.

FIG. 4 is a block diagram showing a configuration of the inverter unit of the embodiment.

FIG. 5 is a circuit diagram of a rectifying / smoothing circuit and an inverter circuit of the same embodiment.

FIG. 6 is a perspective view of an inverter unit according to a second embodiment of the present invention.

FIG. 7 is a circuit diagram of an example of an additional function according to the embodiment;

FIG. 8 is a perspective view of a conventional microwave oven.

FIG. 9 is a bottom view of the conventional microwave oven.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Microwave oven (product) 6 Inverter unit 11 Cover (cooling plate) 12 Base board 13 Main board 14 Sub board 15 Wiring board 16 Rectifying / smoothing circuit 17 Inverter circuit 19 Control circuit 23 Sub board

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Yoshio Maruyama 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Yoshinori Sakai 1006 Kazuma Kadoma, Osaka Prefecture F-term in Matsushita Electric Industrial Co., Ltd. (Reference) 3K072 AA16 BA03 GB01 5H007 CA01 CB04 CB07 CC03 CC32 FA20 HA03 HA04 HA07

Claims (14)

[Claims] 1. A main board in which at least a part of a component handling a high voltage and a large current is mounted on a printed circuit board formed by coating a circuit pattern made of a conductive plate with an insulating resin, and other components. An inverter unit characterized by being combined with a substrate on which is mounted and joined. 2. A main board in which an inverter circuit having a rectifying / smoothing circuit and a switching element is mounted on a printed circuit board formed by covering a circuit pattern formed of a conductive plate with an insulating resin, and controlling the inverter circuit. An inverter unit comprising: a sub board on which a control circuit is mounted; and a base board on which other circuits are mounted, wherein the main board and the sub board are assembled and joined to the base board. 3. The inverter unit according to claim 1, wherein the main board and the sub board are vertically joined to the base board. 4. A cooling plate is provided so as to contact an inverter circuit mounted on a main board.
Inverter unit described in 1. 5. The inverter unit according to claim 4, wherein the cooling plate is constituted by a cover. 6. The inverter unit according to claim 1, wherein a plurality of main boards are provided. 7. A sub-board on which a circuit for extending the function of the inverter circuit is mounted.
The inverter unit according to any one of the above. 8. The inverter unit according to claim 1, wherein the main board and the sub-board are joined to each other by a lead frame perpendicular to both the boards. 9. The inverter unit according to claim 8, wherein a drive signal of the switching element and a current value monitor signal of the inverter circuit are transmitted and AC power is supplied by the lead frame. 10. The inverter unit according to claim 1, wherein the main board and the sub-board are joined to each other by a wiring board. 11. The inverter unit according to claim 10, wherein the wiring board is a wiring board that transmits a drive signal of a switching element and a current value monitor signal of an inverter circuit, and supplies AC power. 12. The main substrate and the sub-substrate are joined to each other by a film-like wiring board.
8. The inverter unit according to any one of 7. 13. The inverter unit according to claim 12, wherein the film-shaped wiring board is a wiring board for transmitting a drive signal of a switching element and a current value monitor signal of an inverter circuit, and for supplying an AC power supply. . 14. A product comprising the inverter unit according to claim 1 in a power circuit.