JPH029291Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to the structure of a circuit board used in a roasting device such as a toaster oven.

[Technical background of the invention]

Conventionally, in this type of circuit board, lead wires that connect components mounted on the circuit board and components not mounted on the circuit board are placed at appropriate positions on the board depending on the arrangement of the components, etc. was.

[Problems with background technology]

For this reason, for example, if the lead wire is placed at the center of the board due to the arrangement of components, etc., it will be drawn out to the outside of the board through between the parts on the board. However, as some of the components are exposed to high temperatures of over 100°C, there is a risk that the insulation of the lead wires may not be maintained, and using lead wires with high heat resistance to prevent this has the disadvantage of being expensive. .
Another drawback was that a long lead wire was required.

[Purpose of invention]

The present invention was developed in view of the above drawbacks, and can ensure safety even when using lead wires with low heat resistance.
The present invention also provides a circuit board for a roasting device that can effectively utilize lead wires.

[Summary of the idea]

The circuit board of the roasting device of the present invention is a roasting device in which at least a part of an electronic circuit including a control circuit for controlling the energization time to the heater is mounted on the circuit board, and the circuit board is provided with a notch. , a connection portion for a lead wire connected to the circuit board is provided around the cutout portion.

[Example of idea]

Next, one embodiment of the present invention will be described based on the drawings.

Figure 1 shows the roasting device 1, with the front facing towards the door body 2.
As shown in FIG. 2, heaters 3 and 4 are provided above and below a roasting chamber (not shown) that is openable and closable. Also, on one side of the front side, protruding from the decorative panel 5, there is a switching knob 6 for switching the heater power, a time setting knob 7 for a mechanical timer operated by a spring or the like, a lamp 8, and a volume knob for setting the time for an electronic timer. 9 slide shafts 10 and an electronic timer operating knob 11 are provided.

Next, FIG. 2 is a diagram showing an electric circuit of the roasting apparatus 1.

In this figure, 15 is an AC power supply that outputs AC100V, and between both ends of this power supply 15, a timer switch 16 and a power switch 17, 18 are connected in parallel to connect the upper and lower heaters 3, 4 and the heater power switch. A switch 19 is connected. In addition,
The timer switch 16 is turned on for the time set by the time setting knob 7, and the power switches 17 and 18 are turned on when the operating knob 11 is pressed down and are self-maintained by a relay coil 20, which will be described later. In addition, the changeover switch 19 is operated by operating the changeover knob 6 to switch between contacts a and
b is switched to change the heater power.

Connection point of power switches 17 and 18 and AC power supply 1
An electronic timer circuit consisting of a high-voltage circuit section 21 and a low-voltage circuit section 22 is connected to one end of the terminal 5. It is structured as follows.

Connection point of power switches 17 and 18 and AC power supply 1
5, a series circuit of a resistor 23 and a lamp 8, and a DC constant voltage power source are connected. The constant voltage power supply includes resistors 25, 26, breather resistors 27, 28, 29, and capacitors 30, 3.
1. It is formed of Zener diodes 32, 33 and a diode 34.

A resistor 36 and a capacitor 37 are connected between the (+) and (-) terminals of this constant voltage power supply via a diode 35.
A time constant circuit consisting of is connected. A Zener diode 38 is connected in parallel to this capacitor 37.
and a resistor 39 are connected to each other, and a resistor 40, a regulator 9, and a capacitor 41 are connected to each other.
A time constant circuit is connected. 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.

An NPN transistor 4 is connected between the connection point of the volume 9 and the capacitor 41 and the (-) terminal.
2. PNP transistor 43, resistor 44, 45
A discharge path consisting of a capacitor 46 and a capacitor 46 is connected thereto.

The connection point between the volume 9 and the capacitor 41 is connected to the gate of an N-channel junction FET 48 via a resistor 47. The drain of this FET 48 is connected to the (+) end via a resistor 49, and is connected to the (+) end via a resistor 5.
0,51 to the base of transistor 52,
It is further connected to the (-) end via a resistor 53, and its source is connected to the emitter of the transistor 52 and to the (-) end via a resistor 54.

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

The collector of the transistor 59 is connected to the (+) end through a parallel circuit of the relay coil 20 and the diode 61, and to the base of the transistor 42 through the resistor 62, and the emitter is connected to the (-) end. has been done.

This circuit operates as follows.

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, the operating knob 11 is pushed down after operating the slide shaft 10 to set the roasting time. Then, the power switches 17 and 18 are turned on, power is supplied to the heaters 3 and 4, and the lamp 8 is turned on. Also, resistance 3
6, 40 and capacitor 3 via volume 9
Charging starts on 7.41. At this point, the terminal voltage of the capacitor 41 is approximately 0V, so the FET
48 is off, and transistors 52, 57, and 59 are on. Therefore, the relay coil 20 is energized and energized to self-hold 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.
Then, the transistors 52, 57, and 59 are turned on, and the relay coil 20 is de-energized, so the power switches 17 and 18 are turned off. At the same time, the collector of the transistor 59 becomes "H" level momentarily, so the transistor 42 is turned on, which also turns on the transistor 43, and the capacitor 4
The charge of 1 is discharged through the discharge path.

Note that the electric charge of the capacitor 37 is
7 is 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
0 consists of a high voltage board part 71 to which parts of the high voltage circuit part 21 are attached, and a low voltage board part 72 to which parts of the low voltage circuit part 22 are attached, as shown in FIG. It has a structure that can be easily divided. Note that only the volume 9 of the low voltage circuit section 22 shown in FIG. 2 is attached to the high voltage substrate section 71.

This low voltage board part 72 has capacitors 30 and 3.
Notches 74 and 75 are provided corresponding to the mounting positions of the breather resistors 1, 37, and 41 and the breather resistors 27, 28, and 29, respectively. The notch portions 74 are connected and fixed to the low voltage board portion 72 by three board connecting portions 76, and the notch portion 75 is connected to the low voltage board portion 72 by two offset board connecting portions 76, and as shown in FIG. Holes 77, 78 are formed.

Furthermore, approximately U-shaped lead wire cutout portions 79 and 95 are formed at one outer end of the low voltage substrate portion 72 and at the center of the outer end of the high voltage substrate portion 71. Lead wire connection holes 80 as lead wire connection terminals are provided around these notches 79 and 95.

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 side of this board 70 is immersed in a solder bath, and each component and lead wires 81, 82 are connected.
Solder and connect to the printed wiring.

After completing the solder connection, the notches 74 and 75 of the low-voltage board section 72 are cut out to form holes 77 and 78. At this time, since the notches 74 and 75 are connected to the low-voltage board part 72 by the board connecting part 76 provided offset, it is easy to press the part where the connecting part 76 is not provided in the direction of the back surface. can be cut out.

In this way, after the solder connection, the notches 74, 7
By notching 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 capacitors 30, 3
1, 37, and 40 toward this hole 77.
Then, as shown in FIGS. 6 and 7, the capacitors 30, 31, 37, and 40 are inserted into the hole 77, and the height L of the entire circuit board is
The thickness of the low-voltage substrate portion 72 can be reduced compared to the case where the substrate 7 is not provided. Also, by providing the holes 78, heat radiation from the breather resistors 27, 28, and 29 is improved.
The influence of temperature on each component on the low voltage board section 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 substantially both ends of the substrate 70 with the perforation 73 for division inside. In addition, since the connections are made around the notches 79 and 95, the operability during installation and connection to the board 70 can be improved, and when the high voltage board part 71 and the low voltage board part 72 are separated as described later, Since the length of the lead wire 82 can be made long and uniform, it is convenient when the high voltage substrate section 71 and the low voltage substrate section 72 are disposed apart from each other.

In addition, 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 high. The drawback is that it is difficult to handle.

Next, the circuit board is energized and its 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 as shown in FIG. Moreover, it is provided below the inner surface of the decorative plate 5, and the slide shaft 10 of the volume 9 is made to protrude from the decorative plate 5.

As shown in FIG. 9, this low voltage board section 72 is fixed to the lower surface of a bottom plate 83 with an insulating plate 84 in between, with the back surface facing upward, using screws 85. The periphery 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 .

Note that the lead wire notch 7 of the low voltage board portion 72
9, the insulating plate 84 is formed with a cutout guide portion 91 having an upwardly rising guide piece 90, and the bottom plate 83 is formed with a substantially U-shaped cutout portion 92. Therefore, the low voltage substrate section 72 and the high voltage substrate section 7
1, the lead wire 82 is connected to the bottom plate 83 from the surface of the low voltage board part 72 through the notch part 79 of the low voltage board part 72, the notch guide part 91 of the insulating plate 84, and the notch part 92 of the bottom plate 83. pulled out to the top,
It is connected to the high voltage substrate section 71 from the back side of the high voltage substrate section 71 via a notch 95 .

Note that the lead wire connection holes 8 of both substrate parts 71 and 72
0 is located around the notches 79 and 95, the low voltage board part 72 and the high voltage board part 71 can be separated by the length of the lead wire 82, and the lead wire 82 can be used effectively. . In addition, since the parts are not routed between parts, especially the high voltage board part 71
Even if parts such as resistors installed in the device become hot, they will not be affected.

Note that the structure that allows the high-voltage substrate section 71 and the low-voltage substrate section 72 to be divided is not limited to perforations.

Also, a notch 7 for drawing out the lead wire 80 is provided.
9 and 95 are provided on both the substrate parts 71 and 72, but they may be provided only on the high-voltage substrate part 71 or the low-voltage substrate part 72.

Note that the lead wires include both substrate parts 71 and 7.
2, and is not limited to the one that connects the board part 7.
The same effect can be obtained by disposing lead wires connecting parts 1 and 72 and parts provided outside of the substrate parts 71 and 72 in the same manner and pulling them out from the notches 79 and 95.

[Effect of idea]

According to the present invention, a notch is provided in the circuit board,
Because a lead wire connection part for connecting a lead wire to be connected to this circuit board was provided around the notch,
The lead wire can be connected to the lead wire connection part through the notch, and it does not pass near the parts arranged on the circuit board, so even if the parts become high temperature, this effect can be avoided. Since the lead wire is not exposed to heat, safety can be ensured without increasing the heat resistance of the lead wire, and it can be manufactured at low cost. Furthermore, the length of the lead wire can be used effectively, and therefore the length of the lead wire can be shortened. Furthermore, wiring connections can be made easily.

[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, Fig. 3 is a perspective view showing a state in which circuit components are arranged and connected to a circuit board, and Fig. 4
Figure 5 is a perspective view of the circuit board, Figure 5 is a perspective view of the circuit board with the notch cut out, Figure 6 is a side view of the circuit board with circuit components connected, Figure 7 is a plan view of the same as above, FIG. 8 is an exploded perspective view showing how the circuit board is attached to the roasting device, and FIG. 9 is a sectional view showing how the low-voltage board section is attached to the roasting device. 1... Roasting device, 3, 4... Heater, 70...
Substrate, 79, 95... Notch, 80... Lead wire connection hole as lead wire connection part, 81, 82...
…Lead.

Claims (1)

[Scope of utility model registration request] In a roasting apparatus in which at least a part of an electronic circuit including a control circuit for controlling energization time to a heater is mounted on a circuit board, a notch is provided in the circuit board and a lead wire connected to the circuit board is provided. A circuit board for a roasting apparatus, characterized in that a connection part is provided around the notch part.