JPS5864792A - Induction heating cooking device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention cools a plurality of independent heating coil excitation devices housed in a single housing by operating a single cooling device no matter which excitation device is activated. The purpose of this invention is to provide an induction heating cooker housed in a small housing.

Induction heating cookers that utilize induction heating are highly efficient.

It has great features such as safety and cleanliness compared to conventional cookers that use flame or red-hot high-temperature heat sources, but on the other hand, it requires a static power converter to excite the power coil at an ultra-audible frequency. The major challenges were to reduce size, weight, and cost. In particular, in an induction heating cooker having a plurality of heating sections as a main cooker, the heating device section is made into a unit by configuring the cooling system with a single cooling device, and the heating section is integrated with the main body section having a power switch. The combination allows the user to have a choice of combinations, providing great convenience to the user.

An embodiment of the present invention will be described with reference to FIG.

Stationary power converter 2a that drives heating coils 1a and 1b
*2b is connected to the commercial power source 4 via dedicated power switches 3a and 3c. Static power converter 1a, 1b
Although there is no particular restriction on the configuration, as an example, the first
In the figure, a transistor bridge inverter is used. A smoothing capacitor 6, a filter coil 7, and a filter capacitor 8 are connected between the rectified output terminals of a full-wave rectifier 5 connected to a commercial power supply 4 via a power switch 3a.
Two series capacitors 9 and 1o and two NPN capacitors are connected between the terminals of capacitor 8.
Series circuits of transistors 11 and 12 are connected in parallel, and the midpoints of the capacitor 9.10 and the transistors 11.12 are connected to each other via the heating coil 1a.

In other words, when the transistors 11 and 12 are alternately conductive, positive and negative currents flow through the heating coil 1a, generating an alternating magnetic field, and eddy currents are generated in the metal cooking container facing the heating coil, thereby causing induction. Let it heat up. A drive signal for making the transistors 11 and 12 conductive alternately is supplied from the control circuit 13 to the transistors 11 and 12 at optimal timing. Further, since the other static power converters 2b have the same configuration, their explanation will be omitted, but these static power converters do not necessarily have to be transistor inverters, and can operate from the commercial power frequency to the ultra-audible frequency range. It is clear that there is no problem if the frequency can be converted to .

Here, the coil of the 2-pole double-throw relay 14 is connected to the power switch 3.
The cooling fan motor 15 is connected to the load side of the power switch 3a via the normally closed contact of the relay.

At the same time, the fan motor 15 is also connected to the load terminal of the power switch 3b via the normally open contact, so if only the power switch 3a is turned on, the fan motor 15 is connected via the normally closed contact of the relay. A voltage is applied and the fan motor 15 operates. Next, when the power switch 3b is turned on, the relay 14 is energized, so the normally open contact is closed, and the fan motor 15 is excited by the load terminal voltage of the power switch 3b and operates. At this time, the operation of the fan motor is not affected at all by turning on or turning off the power switch 3a.

Therefore, the cooling fan motor is powered by the power switch 3a or 3.
If at least one of b is turned on, it will operate, so the cooling system will necessarily operate while the static power converter is in operation. That is, there is no need to provide a dedicated cooling fan for each static power converter, and a single cooling fan can be used, which can greatly contribute to reducing the size, weight, and cost of the housing.

Next, the case of three static power devices will be explained with reference to FIG. The basic configuration is the same as the example shown in FIG. , relay 1 is connected to the load terminal of sc.
Excitation coils 41) and 14c are connected to each other. The fan motor 15 is connected to the load terminal of the power switch 3a through the normally closed contacts of relays 14b and 14C in series, and when the power switch 3b and AC are in the OFF state, neither of the relays 14b and 14C are excited. When the power switch 3a is turned on, it operates with the load side terminal voltage. When the power switch 3b is turned on, the relay 14b is energized, and its normally open contact is closed, so that the fan motor 15 is operated by the load-side terminal voltage of the power switch 3b. At this time, switch 3a is turned on.
It is not affected at all when turned off. Here, two relays 1
4b.

Regarding the connection of the normally closed contacts of 14C, if the terminals of the fan motor 15 are connected in the order of the contacts of the relay 14b and the contacts of the relay 140 as shown in FIG. 2, even if the power switch 3c is turned on, If the power switch 3b is turned on, the fan motor 15 operates with the load terminal voltage of the power switch 3b.

This gives priority as to which switch will supply power to the fan motor 15, so connect the relay contact of the most frequently used power switch (sb in the case of Figure 2) closest to the fan motor 15. If you did,
Since the power to the fan motor does not switch from one to the other every time another power switch is turned on, if only the relay 14b has a long life, the opening/closing life of the other relay contacts can be substantially extended. It is possible to obtain well-balanced reliability as a device.

Regarding turning on of the power switch 3c, if the power switch 3b is off, the fan motor 15 is operated by the load voltage of the switch 3C, regardless of whether the power switch 3a is on or off. Hereinafter, it is clear that even if the number of heating coils and static power converters increases to four or more, it is possible to drive a single cooling fan by simply adding relays according to the present invention.

A case where the power switch is not a double-ended type will be explained with reference to FIG. The configuration is the same as in FIG. 1, but the power switch 3a
, 3b are single-cut, so one end of the fan motor 15 can be connected to a common bus, and the relay 14 only needs to be a single-pole, double-throw type.

Further, FIG. 4 shows an example where the power supply voltages of the static power converters 2a and 2b are not the same. In this case, the connection configuration is
Although it is the same as the figure, the voltage rating of the fan motor 16 only needs to be matched to a power supply with a low power supply voltage. Then, connect the power switch connected to the higher power source (3C in Figure 4).
) has an impedance of 16 between the load terminal and the relay contact.
By inserting the fan motor 15, the terminal voltage of the fan motor 15 can be kept constant even if the fan motor 15 is connected to a power supply having a voltage lower than its rated voltage.

Next, a description will be given based on FIGS. 5 and 6. In the circuit configuration shown in FIG. 6, the load terminals of the power switches 3a and sb are connected to the heating coils 1a and 1b housed in the unit 17 and the static power converters 2a and 2 through connectors 18.
b. Relay 14. Power is supplied to the fan motor 15.

Here, heaters 19 and 20 are respectively connected between the load terminals as power switches 3a and 3b, and when the temperature of the heater reaches a predetermined value, the power switch 3a is activated.

By opening the contact point 3b and using a power switch with an indirect heater that can freely set the temperature detection set value of the heater, it is possible to make the power supplied to the static power converters 2a and 2b variable. That is, if the unit 17 including the heating section and the main body section 21 including the power switch are separated by the connector 18 as a boundary, and the unit 17 is electrically connected by the connector 18, the main body side Since power on/off and output adjustment can be set, it can be used simply by connecting an induction heating cooking unit having the configurations shown in FIGS. 1 to 4 of the present invention. This makes it possible to prepare units with various combinations of heating parts, such as high output, low output, and large and small heating areas among multiple heating parts, making it easy to meet the diverse needs of users. It becomes possible to respond to Of course, even if a 5SR (solid state relay) using a triac or the like is applied instead of the above-mentioned indirect heating type power switch, the power can still be controlled. FIG. 5 shows an embodiment in which the main body 21 is made into a unit.The main body 21 has power switches 3a, 3b and a storage recess 22 for installing the unit 1. When accommodated in the recess 22 , the connector 18 is electrically connected to the connector 18 .

As explained in detail above, by adopting a double-throw relay, even when multiple static power converters are driven by multiple power supplies, it is possible to cool them with a single cooling fan, which reduces the size and size. Lower noise and weight can be achieved. or,
In the case of configuring an induction heating unit having a plurality of heating parts, the above effects are particularly effective, and since the user can select any combination, it is possible to meet various needs.

[Brief explanation of the drawing]

1, 2, 3, and 4 are circuit diagrams of an induction heating cooker showing an embodiment of the present invention, and FIG. 5 is a perspective view of the same external appearance.
FIG. 6 is a circuit diagram of the same embodiment. 1... Heating coil, 2... Stationary power converter, 306.・、・Power switch, 4・・・・・・
Power supply, 14..., Relay, 15,...
Fan motor for ll. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure 2α Figure 3L -------l-'' Figure 4

Claims (2)

[Claims] (1) A single cooling fan motor is equipped with a plurality of heating coils, a static power converter that excites the plurality of heating coils, and a power switch for the static power converter, and a single cooling fan motor is connected in series. At least one relay is connected to the load terminal of any power switch through its normally closed contact, while the load terminal of the other power switch is connected to the excitation winding of the relay corresponding to the switch and the relay's excitation winding. An induction heating cooker that air-cools a plurality of stationary power converters with a single cooling fan by connecting the fan motor through a normally open contact. (2) A unit section that includes a static power converter for the heating coil, a cooling fan motor, and a relay that switches the connection of the cooling fan motor in the same housing, and a main body section that includes a power switch corresponding to each heating coil. 2. The induction heating cooker according to claim 1, wherein the holder is removable.