KR20000073189A - Microwave oven and controlling method for selecting mode thereof - Google Patents

Abstract

PURPOSE: A microwave oven and mode selection control method is provided to reduce manufacturing cost and assembling procedures by simplifying configuration for switching operation between a magnetron and a grill heater, while preventing overheating of the magnetron. CONSTITUTION: A microwave oven comprises a cooking chamber, a magnetron(35) for supplying microwave to the cooking chamber, a grill heater(33) installed within the cooking chamber and which produces heat, and a switching unit(40) arranged between the magnetron and the grill heater and which supplies an electric power to the magnetron when the temperature of the magnetron is lower than a predetermined level and to the grill heater when the temperature of the magnetron is higher than a predetermined level. The switching unit includes a housing having a temperature sensing surface, a common contact(10) extended from an external power source to the housing, a first selection contact(11) connected to the magnetron, a second selection contact(12) connected to the grille heater, a movable piece having one end connected to the common contact and the other end movable between the first and second selection contacts, and a three-contact thermostat installed to be adjacent to the temperature sensing surface of the housing and which moves the movable piece when the temperature of the magnetron is higher than a predetermined level.

Description

Microwave oven and its mode selection control method {MICROWAVE OVEN AND CONTROLLING METHOD FOR SELECTING MODE THEREOF}

The present invention relates to a microwave oven and a mode selection control method thereof, and more particularly, to a microwave oven and a mode selection control method enabling alternating operation of a magnetron and a heater during cooking of food.

In general, the microwave oven is to cook food by a magnetron that generates electromagnetic waves. The magnetron generates heat during operation, and in order to prevent the magnetron from overheating and being damaged, a cooling fan is installed to cool the magnetron. However, if the cooking time is longer than a predetermined time, the cooling using the cooling fan alone does not provide sufficient cooling effect of the magnetron. Accordingly, TCO is installed on the input power line of the magnetron to cut off power supplied to the magnetron when the magnetron is overheated. I'm trying to.

However, the installation of the TCO can prevent overheating of the magnetron, but as the operation of the magnetron is repeatedly turned on and off by the TCO during the cooking of food, the actual time for the magnetron to operate during the cooking of food is compared to the total cooking time. Short, and accordingly, there is a problem that the cooking time of the food is extended.

Meanwhile, in the case of a composite microwave having a heater in a cooking chamber, the magnetron and the heater are operated simultaneously or selectively depending on the type of food to cook.

Among the composite microwave ovens, the cycle type microwave oven performs a cycle mode in which the grill heater and the magnetron are alternately operated according to time, and the driving circuit of the cycle type microwave oven, as shown in FIG. 85 and grill heaters 83 are provided. In addition, a magnetron TCO 86 that is turned on and off according to the temperature of the magnetron 85 is installed at an input end of the magnetron 85, and a power line extending from the magnetron 85 and the grill heater 83 crosses each other. At this point, a switching unit 50 for selectively supplying power to the grill heater 83 and the high voltage transformer 74 is installed.

The switching unit 50 includes a selection switch 51 for supplying power to one of the grill heater 83 and the high voltage transformer 74, a grill switch 55 for intermittent supply of power to the grill heater 83, And a high voltage switch 60 intermittent to supply power to the high voltage transformer 74.

Here, the selector switch 51 may include a first contact 52 connected to a power source, a second contact 53 connected to a grill heater 83, and a third contact 54 connected to a high voltage transformer 74. It is formed of a three-contact switch having a, the grill switch 55 is connected between the second contact 53 and the grill heater 83 of the selection switch 51 to intermittently control the power to the grill heater 83. The high voltage switch 60 includes a main contact 61 connected to the third contact 54 of the selection switch 51, a grill contact 62 connected to the grill heater 83, and a high voltage transformer 74. It is formed as a three-contact switch having a high voltage contact (63) connected to.

The switching unit 50 alternately drives the magnetron mode for driving only the magnetron 85, the grill mode for driving only the grill heater 83, and alternately drives the magnetron 85 and the grill heater 83 at regular intervals. There are three modes of cycle mode.

In the magnetron mode, the selector switch 51 is connected to the second contact point 53, the grille switch 55 is turned off, and the high voltage switch 60 is connected to the high voltage contact point 63. In the grill mode, the selector switch 51 is connected to the first contact point 52, the grille switch 55 is turned on, and the high voltage switch 60 is connected to the grille contact point 62. In addition, in the cycle mode, the selector switch 51 is alternately connected to the first contact point 52 or the second contact point 53 according to a predetermined time interval, and the grill switch 55 is turned on and the high voltage switch ( 60 is connected to the high voltage contact 63.

Such a conventional cycle type microwave oven is a high voltage switch for driving the magnetron 85 and the grill heater 83 to form a cycle mode in which the magnetron 85 and the grill heater 83 are alternately operated. In addition to the 60 and grille switches 55, a selection switch 51 for selecting the magnetron 85 and the grill heaters 83 is provided. Therefore, there is a problem that the configuration of the switching unit 50 is complicated, the cost increases, and the assembling work becomes cumbersome.

On the other hand, the cycle type microwave oven is also equipped with a magnetron TCO 86, so that when the magnetron 85 is overheated to cut off the power supplied to the magnetron 85. Accordingly, when operating in the magnetron mode, if the temperature of the magnetron 85 rises by more than a predetermined value, since the operation of the magnetron 85 is stopped, food is not cooked until the magnetron 85 is cooled.

In addition, in the cycle mode, since the driving of the magnetron 85 and the grill heater 83 is determined according to a preset time, the grill heater 83 is driven before the set time elapses even if the operation of the magnetron 85 is stopped. There is no way to do this. Therefore, there is a problem that the cooking time of the food is extended by the time during which the driving of the magnetron 85 is stopped for cooling the magnetron 85.

Accordingly, an object of the present invention is to provide a microwave oven and a mode selection control method for simplifying the configuration of the switching unit, thereby reducing the cost and simplifying the assembly work.

It is still another object of the present invention to provide a microwave oven and a mode selection control method thereof which enable cooking of food at an optimum time while preventing overheating of the magnetron.

1 is a schematic configuration diagram of a driving circuit of a microwave oven according to the present invention;

2 is a cross-sectional view of the switching unit of FIG.

3 is a schematic configuration diagram of a driving circuit of a conventional microwave oven.

<Description of the symbols for the main parts of the drawings>

1: alternating switch 4: bimetallic element

6: Actuator 10: Common contact

11: 1st selection contact 12: 2nd selection contact

13 Movable Part 21 First Commercial AC Power Line

22: second commercial AC power supply line 24: high voltage transformer

33: grill heater 35: magnetron

40: switching unit 41: selection switch

42: main contact 43: grill contact

44: high voltage contact

The object of the present invention is a microwave oven having a cooking chamber, a magnetron for supplying electromagnetic waves into the cooking chamber, and a grill heater installed on one side of the cooking chamber to generate heat, between the magnetron and the grill heater. It is interposed, it is achieved by a microwave oven, characterized in that it comprises switching means for providing a power supply to the magnetron when the temperature of the magnetron is less than a predetermined, and to provide the power to the grill heater when the temperature of the magnetron is more than a predetermined. .

Here, the switching means, the housing having a temperature sensing surface; A common contact extending into the housing from an external power source; A first selective contact connected to the magnetron; A second selective contact connected to the grill heater; A movable piece, one end of which is connected to the common contact and the other end of which is movable between the first selective contact and the second selective contact; The magnetron is installed adjacent to a temperature sensing surface in the housing, and is formed of an alternating switch, which is a three-contact thermostat including a bimetal element for inverting a curved direction and shifting the movable piece when the temperature of the magnetron rises by a predetermined value or more. Adaptive operation depends on temperature.

Preferably, the movable piece is connected to the first selective contact, and the movable piece is preferably connected to the second selective contact when the bimetal element is inverted.

On the other hand, interposed between the bimetal element and the movable piece further comprises an actuator for pressing and releasing the movable piece in accordance with the inversion of the bimetal element can facilitate the folding of the movable piece.

And a main contact connected to the first selective contact of the alternating switch, a grill contact connected to the grill heater, and a high voltage contact connected to the high voltage transformer, wherein the common contact is located at one side of the grill contact and the high voltage contact. By further including a selection switch that is selectively connected, it is possible to drive the grill heater alone.

On the other hand, the above object, according to another field of the present invention, in the mode selection control method of a microwave oven having a cooking chamber, a magnetron for supplying electromagnetic waves into the cooking chamber, and a grill heater installed on one side of the cooking chamber to generate heat Sensing the temperature of the magnetron; And providing power to the magnetron when the temperature of the magnetron is below a predetermined value, and providing power to the grill heater when the temperature of the magnetron is above a predetermined value. Can be.

Here, it is preferable to further include the step of supplying to either side of the grill heater or the magnetron by intermittently intercepting the power provided to the magnetron.

Hereinafter, the present invention will be described in detail with reference to the drawings.

As shown in FIG. 1, the cycle type microwave oven has first and second commercial AC power lines 21 and 22 connected to a power supply unit 25 for supplying power from the outside. Between the second commercial AC power supply lines 21 and 22, a low voltage transformer 23 for lowering an input voltage, a motor driver 26 for driving various motors, a grill driver 31 for operating a grill, and The high voltage transformer 24 for driving the magnetron 35 is sequentially connected in parallel.

The motor driving unit 26 includes a cooking chamber lamp 27, a drive motor 28 for rotating the turntable, and a part between the first commercial AC power supply line 21 and the second commercial AC power supply line 22. Fan motor 29 for driving the blower fan for cooling, and the timer motor 30 for driving the timer are made in parallel to be driven integrally. Here, the power line from the timer motor 30 is connected to the first commercial AC power supply line 21, and the power lines from the lamp 27 and the fan motor 29 are respectively the second commercial AC power supply line 22. )

The grill driving unit 31 includes a grill TCO 32 and a grill heater on a power line connected between the first commercial AC power supply line 21 and the second commercial AC power supply line 22 in parallel with the motor driving unit 26. 33 are sequentially connected and formed.

Meanwhile, the first commercial AC power supply line 21 has one side contact connected to the power supply unit 25 and the other side to which the power line extending from the timer motor 30, the grill heater 33, and the high voltage transformer 24 are respectively connected. The timer switch 36 which has a contact is arrange | positioned. Therefore, when the external timer knob is selected to set the cooking time, the timer switch 36 is turned on to supply power to the timer motor 30, the grill heater 33 or the high voltage transformer 24, and the timer motor ( The grill heater 33 or the high voltage transformer 24 is driven during the set time at which the 30 is operated.

On the second commercial AC power supply line 22, a first switch 37 is provided between the power supply line from the lamp 27 and the power supply line from the fan motor to be turned on and off as the door is opened and closed. On the second commercial AC power supply line 22, a switching unit 40 for selectively supplying power to the grill heater 33 and the high voltage transformer 24 is installed according to the temperature of the magnetron 35.

The switching unit 40 is composed of an alternating switch 1 formed of a three-contact thermostat and a selection switch 41 formed of a three-contact switch, and the alternating switch 1 is curved in accordance with the temperature of the magnetron 35. Is reversed, and the selection switch 41 operates in accordance with a signal from the controller. The selection switch 41 has a main contact 42 connected to the alternating switch 1, a grill contact 43 connected to the grill heater 33, and a high voltage point 44 connected to the high voltage transformer 24.

The alternating switch 1 includes a common contact 10 connected to the power supply 5 side, a first selective contact 11 selectively connected to the common contact 10, and connected to the grill heater 33, and selected. It has the 2nd selective contact 12 connected to the main contact 42 of the switch 41. As shown in FIG. This alternate switch 1, as shown in Figure 2, the outer appearance is formed by the housing 2, the cover 3 and the cap 5, the receiving space between the cover 3 and the cap (5) The bimetal element 4 in which the bending direction is reversed according to the temperature of the magnetron 35 is accommodated. Here, the cap 5 is formed of a metal body having a good heat transfer such as aluminum to form a temperature sensing surface.

Three terminals, such as the first and second terminals 16 and 17 and the main terminal 18, are attached to an outer side of one side of the housing 2 that faces the lid 3, and one side of each terminal is provided. The main terminal 18 is connected to the common contact 10 so that the main terminal 18 extends into the housing 2, and the first terminal 16 and the second terminal 17 are respectively the first selective contact 11 and the second selective contact. Connected to (12). Here, the movable between the first selection contact 11 and the second selection contact 12 extends from the common contact 10 and selectively contacts one of the first selection contact 11 and the second selection contact 12. Part 13 is interposed.

On the other hand, between the movable piece 13 and the bimetallic element 4, an actuator 6 for pressurizing or releasing the movable piece 13 in accordance with the bending direction of the bimetallic element 4 is interposed. ) Is slidably accommodated in the longitudinal direction in the through hole 7 formed in the central region of the lid 3.

In the alternating switch 1 having such a configuration, the bimetal element 4 is normally curved to protrude toward the cap 5, and the actuator 6 is spaced apart from the movable piece 13. Accordingly, the movable piece 13 is in contact with the first selective contact 11 adjacent to the cover 3 side, and the first terminal 16 and the main terminal 18 are electrically connected to each other and connected to the first terminal. Power is supplied to the selector switch 41. At this time, when the selector switch 41 is connected to the grill contact 43, power is supplied to the grill heater 33 to heat the grill heater 33, and when connected to the high voltage contact 44, the high voltage transformer 24 is connected. Power is supplied to the magnetron 35 is to operate.

On the other hand, if the temperature of the magnetron 35 rises by more than a predetermined time during the operation of the magnetron 35 and the curvature direction of the bimetal element 4 is reversed, the bimetal element 4 curves out toward the housing 2 and operates. The sieve 6 presses the movable piece 13. Then, the movable piece 13 and the second selection contact 12 come into contact with each other, and the second terminal 17 and the main terminal 18 are connected to each other so that the selection switch 41 is connected to the grill contact 43 and the high voltage contact ( The power supply is applied to the grill heater 33 even if it is connected to any one of 44, so that the grill heater 33 generates heat.

The cycle type microwave oven has a first selective contact point 11 in which the movable piece is operated according to the magnetron 35 mode for driving only the magnetron 35, the grill mode for operating only the grill heater 33, and the temperature of the magnetron 35. And the cycle mode for alternately driving the magnetron 35 and the grill heater 33 by alternately contacting the second selective contact 12 with each other.

With this configuration, when cooking food, the first switch 37 is turned off when food is first accommodated in the cooking chamber and the door is closed. Then, by selecting one of the magnetron mode, the grill mode and the cycle mode by operating the operation panel, and setting the desired cooking time by operating the timer knob, the timer switch 36 is turned on, and the timer motor 30 and The magnetron 35 is activated.

On the other hand, at the time of mode selection, since the alternating switch 1 is normally connected to the first selection contact 11, the mode is determined according to the selection of the selection switch 41. First, when the magnetron mode is selected, the selection switch 41 is connected to the high voltage contact 44 in accordance with a signal from the control unit in the state where the alternating switch 1 is connected to the first selection contact 11, and the power supply is connected to the high voltage contact 44. The magnetron 35 is operated by being supplied to the transformer 24. When the grille mode is selected, the selector switch 41 is connected to the grille contact 43 according to a signal from the control unit while the alternating switch 1 is connected to the first selection contact 11, and the power supply is connected to the grill heater ( 33 is supplied to the grill heater 33 generates heat.

In the cycle mode, like the magnetron mode, when the selector switch 41 is connected to the high voltage contact 44 while the alternating switch 1 is connected to the first select contact 11, the magnetron 35 is operated. do. If the temperature of the magnetron 35 rises by more than a predetermined value while the magnetron 35 is operating in this manner, the curved direction of the bimetal element 4 is reversed, and the movable piece 13 is pressed by the actuator 6 to be operated. The piece 13 is connected to the second selective contact 12. Then, the power from the power supply unit 25 is supplied to the grill heater 33 so that the grill heater 33 generates heat. When the temperature of the magnetron 35 decreases after a predetermined time, the bimetal element 4 is inverted to the normal state again, and the movable piece 13 is also connected to the first selective contact 11 again, thereby providing the magnetron 35. ) Is activated and the grill heater 33 is deactivated.

During cooking of the food, the magnetron 35 and the grill heater 33 are repeatedly turned on and off in accordance with the temperature of the magnetron 35. Therefore, when the magnetron 35 stops operating conventionally, the grill heater 33 does not operate automatically, thereby preventing the cooking time from being extended.

Meanwhile, even in the magnetron mode, when the magnetron 35 is overheated, the grill heater 33 is automatically operated by the alternating switch 1, so that the magnetron 35 is intermittently operated during the conventional cooking. Accordingly, the cooking time can be prevented from being extended.

Thus, in the present invention, by controlling the operation of the magnetron 35 with a three-contact thermostat, when the temperature of the magnetron 35 rises more than a predetermined, it is possible to stop the operation of the magnetron 35, so that Even if the TCO is not used, overheating of the magnetron 35 can be prevented. In addition, it is possible to simplify the structure by using only a three-contact thermostat and a three-contact switch, which have conventionally used a magnetron TCO for preventing overheating of the magnetron 35 and a plurality of switches for the operation of the magnetron 35. Will be.

As described above, according to the present invention, by simplifying the configuration for preventing the overheating of the magnetron and the alternating operation between the magnetron and the grill heater, it is possible to reduce the cost and simplify the assembly work, while preventing the magnetron from overheating It is possible to obtain an effect of allowing food to be cooked at an optimum time.

Claims (7)

In a microwave oven having a cooking chamber, a magnetron for supplying electromagnetic waves into the cooking chamber, and a grill heater installed on one side of the cooking chamber to generate heat, A switching means interposed between the magnetron and the grill heater and providing power to the magnetron when the temperature of the magnetron is lower than a predetermined value, and providing power to the grill heater when the temperature of the magnetron is higher than a predetermined temperature. Microwave oven. The method of claim 1, The switching means, A housing having a temperature sensing surface; A common contact extending into the housing from an external power source; A first selective contact connected to the magnetron; A second selective contact connected to the grill heater; A movable piece, one end of which is connected to the common contact and the other end of which is movable between the first selective contact and the second selective contact; It is installed adjacent to the temperature sensing surface in the housing, it is an alternating switch formed of a three-contact thermostat having a bimetal element for switching the movable piece by inverting the curved direction when the temperature of the magnetron rises more than a predetermined microwave. The method of claim 2, Normally the movable piece is connected to the first selective contact, and the movable piece is connected to the second selective contact when the bimetal element is inverted. The method of claim 3, wherein And an actuator interposed between the bimetal element and the movable piece to pressurize and release the movable piece in response to the inversion of the bimetal element. The method of claim 1, And a main contact connected to the first selective contact of the alternating switch, a grill contact connected to the grill heater, and a high voltage contact connected to the high voltage transformer, wherein the common contact is located at one side of the grill contact and the high voltage contact. Microwave oven further comprises a selection switch that is selectively connected. In the mode selection control method of the microwave oven having a cooking chamber, a magnetron for supplying electromagnetic waves into the cooking chamber, and a grill heater installed on one side of the cooking chamber to generate heat, Sensing the temperature of the magnetron; And supplying power to the magnetron when the temperature of the magnetron is lower than a predetermined value, and providing power to the grill heater when the temperature of the magnetron is higher than or equal to a predetermined temperature. The method of claim 6, And intermittently supplying power supplied to the magnetron to supply the grill heater or the magnetron to one side of the grill heater or the magnetron.