JP2002310435A - High frequency heating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stable cooling construction without changing a cooling air amount circulating in an instrument and an air pressure distribution of cooling air even when power supply voltage or frequency is changed. SOLUTION: A flower guide 67 including an air suction port 65 and an exhaust port 66 therein is disposed around a circulation fan motor 62, and a damper 70 is constructed at the air suction port 65 or air exhaust port 66 of the flower guide 67, which serves to change an opening area of the air suction port 65 or the exhaust port 66 owing to air pressure generated in response to the number of revolutions of the circulation fan motor 62. Accordingly, a stable cooling construction is ensured without changing a cooling air amount circulation in the instrument and an air pressure distribution of cooling air even when power supply voltage or frequency is changed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency heating device such as a microwave oven, and more particularly to a cooling structure.

[0002]

2. Description of the Related Art A conventional high-frequency heating apparatus is shown in FIGS.

FIG. 4 is a longitudinal sectional view of a high-frequency heating device.
3 is a horizontal sectional view of the high-frequency heating device. 4 and 5, there is a magnetron 3 coupled to the heating chamber 1 via a waveguide 2. An inverter 4 which is a power supply for driving the magnetron 3 is held by a holding table 5, and a lower portion of the exterior of the main body is held. It is fixed to the formed bottom plate 6. A cooling fan 7 and an orifice 8 are provided behind the magnetron 3 so as to cool the magnetron 3, the inverter 4, and the control device 9. An air guide 10 is provided in front of the magnetron 3, and a lamp 1 is provided below the air guide 10.
1 is provided to illuminate the heating chamber 2. Outside the lower surface of the heating chamber 1, a motor 13 is provided via a motor mounting plate 12.
The tray support 14 on which the object to be heated is placed is rotated. A heater 15 is provided outside the upper surface of the heating chamber 1, and a hot-air blowout hole (outer peripheral portion) provided on the upper surface of the heating chamber 1.
16 and the hot air suction hole 17 (central portion) through the heater 1
5 is circulated to the heating chamber 1 by the rotation of the hot air circulating fan 18 and is heated. Above the heater 15, a heat insulating plate 19 is provided for shutting off the heat of the heater 15 and keeping the heat. The hot air circulation fan 18 is provided below the bearing 20, and a pulley 21 is provided above the bearing 20. The rotation of the pulley 21 is configured to transmit the rotation of the circulation fan motor 22 via the rotating belt 23. When the circulating fan motor 22 rotates, the pulley 21 rotates via the rotating belt 23, and the hot air circulating fan 18 provided below the bearing 20 rotates, so that the heat of the heater 15 is transferred from the hot air blowing hole 16 to the heating chamber 1. To the heater 1 through the hot air intake hole 17.
The heating chamber 1 is heated by circulating heat returning to the side 5.
The circulation fan motor 22 is disposed at the upper right front of the heating chamber 1, surrounds the periphery of the circulation fan motor 22 with a wall 24, and has an intake port 25 necessary for circulating cooling air from bottom to top in the apparatus. Guide 27 provided with air outlet section 26
There is. When the circulation fan motor 22 rotates, cool air is drawn in from the outside of the apparatus through the suction holes 28 and the suction holes 29 of the bottom plate 5, and rises around the dish receiving motor 13, the inverter 4, the lamp 11, and the like. , Passes through the circulation fan motor 22, is ejected from the exhaust port 26, passes over the heat insulating plate 19, and is discharged from the exhaust hole 31 of the body 30 constituting the exterior of the device. Each component in the device is continuously cooled by the circulation of the cooling air described above.

[0004]

However, in the above conventional configuration, if the power supply voltage or the frequency increases or decreases,
Due to the general characteristics of the circulating fan motor 22, the number of rotations increases and decreases as the power supply voltage or the frequency increases and decreases as shown in the graph of FIG. For this reason, if the opening area of the exhaust port is the same, the amount of air blown out from the exhaust port 26 provided in the blower guide 27 will increase or decrease as shown in the graph of FIG. Under the influence of this, if the amount of cooling air circulating in the device through the air inlet 25 and the air outlet 26 of the air guide 27 increases or decreases, the flow of the cooling air and the distribution of the pressure of the cooling air in each part of the inside of the device become delicate. Change. As a result, there is a problem that the cooling state of each component changes and the component temperature changes.

[0005] In order to share the circulation fan motor 22 having a rated voltage of 240 V / 50 Hz, a rated voltage of 220 V / 60 H is used.
If it is used for a high frequency heating device having a z specification or a rated 240 V / 60 Hz specification, the power supply voltage and frequency naturally change, and the number of revolutions of the circulation fan motor 22 changes. Therefore, the cooling performance is reviewed for each power supply specification. Need arises,
There are problems that a dedicated air guide is required and that the high-frequency heating device cannot be shared.

The present invention solves the above-mentioned conventional problems, and suppresses a change in the flow of the cooling air and the pressure distribution of the cooling air in each part circulating in the device even when the power supply voltage or the frequency changes, thereby stabilizing the cooling air. It is intended to provide improved cooling performance.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned conventional problems, the present invention provides an air inlet or an outlet of a blower guide by using a wind pressure generated in accordance with the rotation speed of a circulating fan motor. The damper has a function of changing the opening area of the opening or the exhaust port. As a result, even if the power supply voltage or the frequency changes, the amount of cooling air ejected from the exhaust port of the air blowing guide becomes constant due to the function of the damper, so that the amount of cooling air circulating in the device remains constant. As a result, the flow of the cooling air and the pressure distribution of the cooling air do not change, and the cooling state of the components can be kept constant. Therefore, the effect of keeping the temperature of the components in the device constant can be obtained.

[0008]

According to the first aspect of the present invention, a ventilation fan having an intake port and an exhaust port is disposed around a circulation fan motor, and a circulation fan is provided at an intake port or an exhaust port of the ventilation guide. According to the present invention, there is provided a damper configured to change an opening area of an intake port or an exhaust port by a wind pressure generated according to the number of rotations of a motor. The damper provided at the intake or exhaust port of the blower guide changes the opening area according to the wind pressure generated by the rotation speed of the circulating fan motor, so the amount of cooling air blown out from the exhaust port of the blower guide is constant. It can be. Thus, even if the power supply voltage or frequency changes, the amount of cooling air circulating in the device can be kept constant without changing. As a result, the flow of the cooling air and the pressure distribution of the cooling air do not change, and the cooling state of the components can be kept constant. Therefore, the effect of keeping the temperature of the components in the device constant can be obtained.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view of a high-frequency heating apparatus according to an embodiment of the present invention, FIG. 2 is a horizontal sectional view of the high-frequency heating apparatus, and FIG. 3 is a sectional view of a principal part around a damper of the high-frequency heating apparatus. Things.

2 and 3, there is provided a magnetron 43 coupled to a heating chamber 41 via a waveguide 42. An inverter 44, which is a power supply for driving the magnetron 43, is held on a holding table 45. It is fixed to a bottom plate 46 forming the lower part of the exterior. A cooling fan 47 and an orifice 48 are provided behind the magnetron 43, and are configured to cool the magnetron 43, the inverter 44, the control device 49, and the like. An air guide 50 is provided in front of the magnetron 43, and a lamp 51 is provided below the air guide 50 to illuminate the heating chamber 42. Outside the lower surface of the heating chamber 41, there is a dish receiving table motor 53 via a motor mounting plate 52, which rotates a dish receiving table 54 on which an object to be heated is placed. A heater 55 is provided outside the upper surface of the heating chamber 41, and the heat of the heater 55 is passed through a hot air circulating fan 58 through a hot air blowing hole (outer peripheral portion) 56 and a hot air suction hole 57 (central portion) provided on the upper surface of the heating chamber 41. Is rotated in the heating chamber 41 and heated.

A heat insulating plate 59 is provided above the heater 55 to block the heat of the heater 55 and keep the heat.
The hot air circulation fan 58 is provided below the bearing 60, and a pulley 61 is provided above the bearing 60. The rotation of the pulley 61 is configured to transmit the rotation of the circulation fan motor 62 via the rotating belt 63.
When the circulation fan motor 62 rotates, the pulley 61 rotates via the rotating belt 63, and the hot air circulation fan 58 provided below the bearing 60 rotates, so that the heater 55 is rotated.
Is discharged from the hot air outlet hole 56 into the heating chamber 41 and returned from the hot air inlet hole 57 to the heater 55 side, causing heat circulation to heat the heating chamber 41. Circulating fan motor 6
Numeral 2 is disposed at the upper right front of the heating chamber 41, surrounds the periphery of the circulation fan motor 62 with a wall 64, and has an intake port 65 and an exhaust port necessary for causing convection of cooling air from bottom to top in the apparatus. There is a blower guide 67 provided with a part 66. When the circulating fan motor 62 rotates, cool air is drawn in from the outside of the apparatus through the suction holes 68 and the suction holes 69 of the bottom plate 46, and rises around the dish receiver motor 53, the inverter 44, the lamp 51, etc. , The air pressure pushes a damper 70 provided at the exhaust port 66, the air is exhausted, passes through the heat insulating plate 59, and is exhausted from the exhaust hole 72 of the body 71 constituting the exterior of the device.

Next, the operation and operation will be described. In FIG. 3, the circulation fan motor 6 in the air blow guide 67
When 2 rotates, a flow is created in which air is sucked in from the intake port 65 and discharged from the exhaust port 66, and a wind pressure corresponding to the number of revolutions is generated in the blower guide 67. Since the wind pressure acts to push open the damper 70 provided in the exhaust port 65 of the blower guide 67, the opening angle of the damper increases as shown in FIG. The opening area of the exhaust port 66 increases. If the wind pressure according to the rotation speed is weak, the opening angle of the damper becomes small and the opening area of the exhaust port 66 becomes small as shown in FIG. When the damper 70 of the exhaust port 66 is operating in a state as shown in FIG. 3C, if the power supply voltage increases for some reason, the rotation of the circulation fan motor 62 as shown in the graph of FIG. Because the number rises according to the voltage,
7, the opening angle of the damper 70 increases, and the opening area of the exhaust port 66 increases. Then, since the opening area is increased, the exhaust resistance of the exhaust port 66 is reduced, and the rotation speed is reduced by the reduced load of the exhaust resistance due to the characteristics of the circulation fan motor 62. When the number of revolutions of the circulation fan motor 62 decreases, the wind pressure in the blower guide 67 decreases, the opening angle of the damper 70 decreases, and the opening area of the exhaust port 66 decreases. Then, as the opening area becomes smaller, the exhaust resistance increases,
Due to the characteristic of the circulating fan motor 62, the rotation speed is increased by the increase in the load of the exhaust resistance. Damper 70
By repeating such an operation, the airflow blown out from the exhaust port 66 at a balanced position is kept constant.

Note that the position of the damper 70 is
7 has been described on the exhaust port 66 side, but it goes without saying that the same effect can be obtained even if it is provided on the intake side 65.

Although the shape of the damper 70 has been described as a plate, it goes without saying that the same effect can be obtained in any shape as long as the shape receives the wind pressure.

[0016]

As described above, according to the first aspect of the present invention, even if the power supply voltage or the frequency changes, the amount of air blown out from the exhaust port of the blower guide can be kept constant, so that the circulation in the equipment can be achieved. The amount of cooling air that flows is constant without changing. As a result, the flow of the cooling air in the device and the pressure distribution of the cooling air do not change, so that the cooling state of the components can be kept constant and the temperature of the components in the device can be kept constant. In addition, since it can be used without slight differences in power supply voltage or frequency, the effect of sharing parts can be obtained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a high-frequency heating device according to a first embodiment of the present invention.

FIG. 2 is a horizontal sectional view of the high-frequency heating device according to the first embodiment of the present invention.

FIG. 3A is a cross-sectional view of a main part around a damper of the high-frequency heating device according to the first embodiment of the present invention. FIG. 3B is a cross-sectional view of another main part around the damper of the high-frequency heating device. Sectional view of other main parts around damper

FIG. 4 is a longitudinal sectional view of a conventional high-frequency heating device.

FIG. 5 is a horizontal sectional view of a conventional high-frequency heating device.

6A is a graph showing the relationship between the number of rotations of a circulating fan motor of a conventional high-frequency heating device and the power supply voltage. FIG. 6B is a graph showing the relationship between the amount of air blown out from an exhaust port of a blower guide of the conventional high-frequency heating device and the power supply voltage. Graph showing relationship

[Explanation of symbols]

 41 heating chamber 43 magnetron 55 heater 62 circulation fan motor 65 intake port 66 exhaust port 67 air guide 70 damper

Claims (1)

[Claims] 1. A heating chamber for storing an object to be heated, a high frequency generator for irradiating the heating chamber with radio waves, a heater for heating the heating chamber, and a power supply for driving the high frequency generator and the heater. A cooling fan motor for cooling the high frequency generator, the power supply unit and components in the device, and a circulating fan motor for cooling the power supply unit and components in the device,
A blower guide for circulating cooling air in the device, and the blower guide provided with an intake port and an exhaust port around the circulation fan motor; and an intake port or an exhaust port of the blower guide. A high-frequency heating device comprising a damper having a function of changing an opening area of an intake port or an exhaust port by a wind pressure generated according to a rotation speed of the circulation fan motor.