JPH035766Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Purpose of the Invention] (Field of Industrial Application) The present invention relates to a roasting device such as a toaster oven, and relates to the structure of a circuit board of a circuit for controlling a heater.

(Prior Art) Conventionally, this type of roasting equipment has a structure in which components forming a control circuit for timer control of a heater, etc. are connected to a circuit board without separating the components into a high-voltage circuit section and a low-voltage circuit section. It is becoming.

(Problem that the invention attempts to solve) However, since the insulation distance between component wiring stipulated by the Electrical Appliance and Materials Regulations differs between high-voltage circuit sections and low-voltage circuit sections, if they are designed integrally, for example, high-voltage circuit section If the low-voltage circuit and the high-voltage circuit are adjacent to each other, an insulation distance must be provided to match the high-voltage circuit, which increases the size of the circuit board, and if the circuit board is to be made smaller, the arrangement of parts, printed wiring, etc. The problem was that it became complicated and unreasonable.

The present invention was developed in view of the above-mentioned problems.The high-voltage circuit and the low-voltage circuit are separated and connected to separate circuit board parts, and the circuit components can be connected to each other without forming unnecessary insulation distances. In addition to efficient design and component placement, good heat dissipation is possible, the heater can be controlled reliably without being affected by the temperature rise in the roasting chamber, the circuit board can be made smaller, and it is easy to assemble. The present invention provides a roasting device with improved performance.

[Structure of the idea]

(Means for Solving the Problems) The roasting apparatus of the present invention includes a heater, a high voltage circuit section including a power supply circuit, a breather resistor connected to the high voltage circuit section and a step-down breather resistor, and a capacitor and a resistor. In the roasting apparatus, the high-voltage circuit part and the low-voltage circuit part are separated and separated. A high-voltage side circuit board section to which the components of the high-voltage circuit section are connected is disposed in the roaster main body in which the heater is disposed, and a low-voltage side circuit board section to which the components of the low-voltage circuit section are connected is provided. The side circuit board section is disposed outside the roaster main body with the side on which the components are disposed facing the outside, and the low-pressure side circuit board section is covered with a cover having ventilation holes.

(Function) In the roasting apparatus of the present invention, parts of the high-voltage circuit section are wired while maintaining the insulation distance required for the high-voltage circuit, and components of the low-voltage circuit section are wired while maintaining the insulation distance necessary for the low-voltage circuit. There is no need to form unnecessary insulation distances, and the circuit board can be made smaller. In addition, the pressure-down breather resistor, which generates a large amount of heat, is installed on the outer surface of the circuit board of the low-voltage circuit located outside the roaster body, and the vent hole in the cover that covers the low-voltage circuit board is installed on the outside of the roaster body. Heat is dissipated through the ventilation holes that it passes through.

(Example) Next, an example of the present invention will be described based on the drawings.

In FIG. 1, 1 is a roaster main body, and this main body 1 has a roasting chamber (not shown) whose front surface can be opened and closed with a door body 2. Heaters 3 and 4 shown in the figure are provided, respectively. Further, on the front side of the decorative plate 5 provided on one side of the front side of the main body 1, there is a switching knob 6 for a switch that changes the heater power, a time setting knob 7 for a mechanical timer switch operated by a spring, etc., a lamp 8,
Volume 9 is the time setting knob for the electronic timer.
A slide shaft 10 and an electronic timer operating knob 11 are provided.

Next, the electric circuit of the roasting device will be explained with reference to FIG.

15 is an AC power supply that outputs AC100V, and a mechanical timer switch 1 is connected between both ends of this power supply 15.
Both the upper and lower heaters 3, 4 and a heater power changeover switch 19 are connected through a parallel circuit with power switches 17, 18 connected in series.
The mechanical timer switch 16 is closed for the time set by the time setting knob 7, and the power switches 17 and 18 are closed when the operating knob 11 is pressed down and are self-maintained by a relay coil 20, which will be described later. be done. Further, the changeover switch 19 is configured so that contacts a and b are changed over by operating the changeover knob 6 to change the heater power.

An electronic timer circuit consisting of a high voltage circuit section 21 and a low voltage circuit section 22 is connected between the connection point of the power switches 17 and 18 and one end of the AC power source 15.

A series circuit of a resistor 23 and a lamp 8, and a DC constant voltage power supply are connected between the connection point of the power switches 17 and 18 and one end of the AC power supply 15. This constant voltage power supply includes a resistor 25,
26, breather resistor for step down 27, 28, 29,
Capacitors 30, 31, Zena diode 32,
33 and a diode 34.

A diode 3 is connected between both terminals of this constant voltage power supply.
A time constant circuit consisting of a resistor 36 and a capacitor 37 is connected through the resistor 36 and the capacitor 37. A Zener diode 38 and a resistor 39 are connected in parallel to the capacitor 37, as well as a time constant circuit including a resistor 40, a regulator 9, and a capacitor 41. The volume control 9 is used to change the set time of the electronic timer by changing the time constant of the time constant circuit, and the resistance value is changed by operating the slide shaft 10.

Further, between the connection point of the volume 9 and the capacitor 41 and the - extreme, an NPN type transistor 42, a PNP type transistor 43, and resistors 44, 4 are connected.
5 and a discharge path consisting of a capacitor 46 are connected.

Furthermore, the connection point between the volume 9 and the capacitor 41 is an N-channel junction type via a resistor 47.
Connected to the gate of FET48. This FET
The drain of 48 is connected to the + terminal via a resistor 49, to the base of the transistor 52 via resistors 50 and 51, and to the - terminal via a resistor 53, and its source is connected to the emitter of the transistor 52. It is also connected to the -extreme via a resistor 54.

Furthermore, the collector of the transistor 52 is connected to a resistor 55.
is connected to the + terminal through a resistor 56 and to the base of a transistor 57 through a resistor 56. The emitter of this transistor 57 is connected to the + terminal, the collector is connected via a resistor 58 to the base of a transistor 59 as a switching element, and the collector is connected via a resistor 60 to the - terminal.

Further, the collector of the transistor 59 is connected to the + terminal through a parallel circuit of the relay coil 20 and the diode 61, and to the base of the transistor 42 via the resistor 62, and the emitter is connected to the - terminal.
Extremely connected.

The operation of this circuit will be explained.

First, when using a mechanical timer, when the roasting time is set with the time setting knob 7, the timer switch 16 is turned on for the set time, and the heaters 3 and 4 are energized.

When using an electronic timer, after setting the roasting time by operating the slide shaft 10, push down the operating knob 11 to turn on the power switch 17,
18 is closed, the heaters 3 and 4 are energized, and the lamp 8 is turned on. Also, resistor 36,4
0 and capacitor 37,4 via volume 9
Charging starts at 1. At this point, the terminal voltage of the capacitor 41 is approximately 0V, so the FET 48 is off and the transistors 52, 57, and 59 are on. Therefore, the relay coil 20 is energized and energized to maintain the closed state of the power switches 17 and 18.

Next, when the set time has elapsed, the terminal voltage of the capacitor 41 reaches the set value and the FET 48 is turned on.
When this FET48 is turned on, the transistor 52,
57 and 59 are turned off, and the relay coil 20 is de-energized, so the power switches 17 and 18 are turned off.
will be released. At the same time, the collector of the transistor 59 becomes "H" level for a moment, so the transistor 42 is turned on, the transistor 43 is also turned on, and the charge in the capacitor 41 is discharged through the discharge path.
Further, the electric charge of the capacitor 37 is reduced by the power switch 17.
After being turned off, it is gradually discharged via the resistor 39 in accordance with the heat capacity of the roasting chamber and the heaters 3 and 4. For this reason, the roasting time from the second time onwards will be adjusted depending on the length of the interval time from the previous time.

As shown in FIG. 3, this electric circuit is formed by attaching each component to a printed wiring board 70 having printed wiring on its back surface. Board 7
As shown in FIG. 4, 0 indicates a high-voltage side circuit board section 71 to which components of the high-voltage circuit section 21 are attached, and a low-voltage circuit section 2.
and a low voltage side circuit board part 72 to which parts No. 2 are attached, and both parts are integrally formed and have a structure that can be easily divided at a perforation 73. In addition, the second
Only the volume 9 of the low voltage circuit section 22 shown in the figure is attached to the high voltage side circuit board section 71.

This low voltage side circuit board section 72 has a capacitor 3.
Notches 74 and 75 are provided corresponding to the mounting positions of 0, 31, 37, and 41 and the mounting positions of breather resistors 27, 28, and 29, respectively. This notch 74 has three
5 is connected and fixed to the low-voltage side circuit board part 72 by two board connection parts 76 provided on one side,
The holes 77, 7 are cut out as shown in FIG.
8 is formed.

Further, a substantially U-shaped lead wire notch 79 is formed at one outer end of the low voltage side circuit board portion 72 .

Further, lead wire connection holes 80 are provided as lead wire connection terminals at the outer end of the high voltage side circuit board section 71, on one side of the outer end of the low voltage side circuit board section 72, and on the inner end side of the lead wire notch section 79. It is being

In addition, FIG. 3 and FIGS. 6 to 9 described later
In the figures, the numbers of some parts are omitted.

On the thus formed substrate 70, as shown in FIG. 3, each component, a lead wire 81 for external connection, and a lead wire 82 for connection between the high voltage circuit section 21 and the low voltage circuit section 22 were arranged. After that, the back surface of the board 70 opposite to the component mounting surface is immersed in a solder bath, and each component and lead wires 81 and 82 are soldered to the printed wiring.

After the solder connection is completed, the notches 74 and 75 of the low voltage side circuit board section 72 are cut out, and the holes 77 and 7 are cut out.
8 will be provided. At this time, since the notches 74 and 75 are connected to the low-voltage side circuit board part 72 by the board connecting part 76 provided offset, it is difficult to press the part where the connecting part 76 is not provided toward the back surface. It can be easily cut out.

In this way, after soldering the notches 74, 7
By cutting out 5, when immersed in the solder bath,
Problems such as solder adhering to the capacitors 30, 31, 37, 41 and the breather resistors 27, 28, 29 and adversely affecting the characteristics of the components can be avoided. Then, after providing the hole 77, the capacitor 30,
31, 37, and 41 toward this hole 77, as shown in FIGS. 6 and 7,
Since the capacitors 30, 31, 37, and 41 are inserted into the holes 77, the height L of the entire circuit board can be reduced by the thickness of the low voltage board portion 72 compared to the case where the holes 77 are not provided. Moreover, by providing the holes 78, heat radiation from the breather resistors 27, 28, and 28 is improved, and the influence of temperature on each component on the low-voltage board portion 72 can be prevented.

Further, the lead wire 82 connecting the high voltage circuit section 21 and the low voltage circuit section 22 can be made longer because it extends between both ends of the substrate 70 with the perforation 73 for division inside. Therefore, the operability when connecting wiring to the board 70 can be improved, and when the high-voltage circuit board section 71 and the low-voltage circuit board section 72 are separated as described later, the length of the lead wires 82 can be made long and uniform. This is convenient when arranging the high voltage side circuit board section 71 and the low voltage side circuit board section 72 apart from each other.

Note that when the distance between the lead wire connection holes 80 is short, in order to arrange the lead wires 82 in a long state, the lead wires 82 curve sharply and the height becomes higher. The drawback is that it is difficult to handle.

Next, the circuit board parts 71 and 72 are energized and their operation is tested. Note that this inspection may be performed after the solder connection is completed and before cutting out the notches 74 and 75.

After the inspection is completed, this board 70 is divided at the perforation 73, and the low voltage side circuit board part 7 is divided as shown in FIG.
2 is provided on the outside of the lower surface of the bottom plate 83 of the roaster main body 1, and the high-pressure side component board part 71 is provided on the inside upper part of the bottom plate 83 and the lower part of the inner surface of the decorative plate 5. stands out.

As shown in FIG. 9, this low-voltage side circuit board section 72 is attached to the lower surface of a bottom plate 83 with an insulating plate 84 interposed therebetween, with the back surface opposite to the component mounting surface facing upward, and the component mounting surface facing outward. It is fixed with screws 85. The periphery of this low-voltage side circuit board section 72 is covered with a cover body 89 having a ventilation hole 86 and having one end engaged with an engagement hole 87 of the bottom plate 83 and the other end fixed to the bottom plate 83 with screws 88. ing.

Note that, corresponding to the lead wire notch 79 of the resistance voltage side circuit board portion 72, the insulating plate 84 has a notch guide portion 91 having an upwardly rising guide piece 90, and the bottom plate 83 has a notch guide portion 91 having a guide piece 90 rising upward. A U-shaped notch 92 is formed. Therefore, the lead wire 82 connecting the low voltage side circuit board section 72 and the high voltage side circuit board section 71 is
is pulled out from the surface of the low voltage side circuit board section 72 to the upper surface of the bottom plate 83 via the notch section 79 of the low voltage side circuit board section 72, the notch guide section 91 of the insulating plate 84, and the notch section 92 of the bottom plate 83. There is.

Note that since the lead wire connection portion 80 of the low voltage side circuit board portion 72 is located near the notch portion 79, the low voltage side circuit board portion 72 and the high voltage side component board portion 71 are connected by the length of the lead wire 82. This allows the lead wires 82 to be used effectively.

Note that the configuration that allows the high-voltage side circuit board section 72 and the low-voltage side circuit board section 72 to be divided is not limited to perforations.

[Effect of idea]

According to the present invention, the components of the high voltage circuit section and the components of the low voltage circuit section are separated and placed on the board, which eliminates unnecessary insulation caused by the adjacent printed wiring of the high voltage circuit and the printed wiring of the low voltage circuit. There is no need to provide a distance, and the printed wiring of the circuit board can be designed efficiently, components can be efficiently arranged, and the circuit board can be made smaller. In addition, even if the circuit board is miniaturized, the arrangement of components and printed wiring are simple, so the workability of assembly and inspection can be improved.

In addition, a high-voltage side circuit board to which parts of the high-voltage circuit are connected is installed inside the roaster body, which increases safety by preventing direct hand contact with the high-voltage side. The low-voltage side circuit board, to which the parts of the low-voltage circuit section are connected, including the breather resistor and the control circuit that controls the energization time to the heater, has a time constant circuit determined by a capacitor and a resistor, with the side where the components are installed facing outward. The circuit board is placed on the outside of the roaster body, and the low-voltage side circuit board is covered with a cover that has ventilation holes, allowing for good heat dissipation from the breather resistor, etc., which generates a large amount of heat for lowering the voltage. without being affected by temperature rise in the roasting chamber.
The heater can be controlled well and the heater can be controlled reliably.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the roasting device of the present invention, FIG. 2 is an electric circuit diagram of the same roasting device, and FIG. 3 is a perspective view showing a state in which circuit components are arranged and connected to the same circuit board.
FIG. 4 is a perspective view of the same circuit board, FIG. 5 is a perspective view of the circuit board with the notch portion cut out,
Fig. 6 is a side view of the component board to which the above circuit components are connected, Fig. 7 is a plan view of the above, Fig. 8 is an exploded perspective view showing the state in which the above circuit board is attached to the roasting device, and Fig. 9 is the same as the above. FIG. 3 is a cross-sectional view showing how the low-voltage side circuit board section is attached to the roasting device. 1... Roasting device, 3, 4... Heater, 9... Volume, 21... High voltage circuit section, 22... Low pressure circuit section, 27, 28, 29... Breather resistor, 3
6,40...Resistor, 37,41...Capacitor,
71...High voltage side circuit board section, 72...Low voltage side circuit board section, 86...Vent hole, 89...Cover.

Claims (1)

[Claims for Utility Model Registration] The heater comprises a heater, a high-voltage circuit section including a power supply circuit, and a time constant circuit connected to the high-voltage circuit section, connected to a step-down breather resistor, and determined by a capacitor and a resistor. In a roasting apparatus having a low-voltage circuit section including a control circuit for controlling energization time, the components of the high-voltage circuit section and the components of the low-voltage circuit section are separated and connected to separate circuit board sections, and the A high-voltage side circuit board section to which the components of the high-voltage circuit section are connected is arranged in the roaster main body in which the heater is arranged, and a low-voltage side circuit board section to which the components of the low-voltage circuit section are connected is arranged on the part arrangement side. A roasting apparatus characterized in that the low-pressure side circuit board section is disposed outside the roaster main body with the outer surface thereof facing, and the low-pressure side circuit board section is covered with a cover having a ventilation hole.