JPH0525694U - High frequency heating device - Google Patents

Abstract

(57) [Abstract] [Purpose] In a microwave oven that drives a magnetron at high frequency using an inverter, the noise suppression effect of the noise filter is reduced under the influence of the leakage magnetic flux from the high-voltage transformer while ensuring cooling of the noise filter. Try not to do it. [Structure] Magnetron 2, high-voltage transformer 3 for applying high voltage to magnetron 2, inverter 4 for high-frequency driving magnetron 2 via high-voltage transformer 3, noise filter 6 connected to external power supply connection cord 5, magnetron 2 and the like. A cooling fan 8 that supplies cooling air and a cooling fan guide 9 that is made of a magnetic material and that electromagnetically isolates the noise filter 6 from the high-voltage transformer 3 are provided.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a high-frequency heating device such as a microwave oven which drives a high-frequency supplying means at a high frequency using an inverter.

[0002]

[Prior Art]

 Recently, microwave ovens have been commercialized that use an inverter to drive a high-frequency supplying means, that is, a magnetron. This inverter switches a large amount of electric power at 30 to 40 KHz and generates a large amount of noise. This noise propagates through the cord connected to the external power supply and gives a radio wave interference to the radio.

In FIG. 2, a noise filter 11 including a choke coil and a capacitor is inserted between the external power supply connecting cord 12 and the inverter 13 so as to prevent such radio interference. However, the noise suppressing effect of the noise filter 11 is considerably reduced by the influence of the leakage magnetic flux from the high voltage transformer 15 which is provided at the subsequent stage of the inverter 13 and applies a high voltage to the magnetron 14.

In order to prevent this, in Japanese Utility Model Laid-Open No. 2-92692, the noise filter is separated from the high voltage transformer by an electromagnetic shield plate. In this case, the electromagnetic shield plate also blocks the cooling air and cools the noise filter. Can't do.

[0005]

[Problems to be solved by the device]

 The present invention ensures the cooling of the noise filter that suppresses the noise from the inverter to the outside, and the noise suppression effect of the noise filter does not decrease under the influence of the leakage magnetic flux from the high voltage transformer. The present invention provides a high frequency heating device.

[0006]

A high-frequency heating device of the present invention comprises a high-frequency supplying means for supplying a high frequency into a heating chamber for containing food, a high-voltage transformer for applying a high voltage to the high-frequency supplying means, and a high-voltage transformer. An inverter that drives the high-frequency supply unit through a lance at a high frequency, a noise filter connected to an external power supply connection cord, a cooling fan that supplies cooling air to the high-frequency supply unit, the high-voltage transformer, and the inverter, and a magnetic body. A cooling fan guide that electromagnetically isolates the noise filter from the high-voltage transformer.

[0007]

[Action]

 By separating the noise filter from the high-voltage transformer by the magnetic fan guide for the cooling fan, the noise filter is not affected by the leakage magnetic flux from the high-voltage transformer, and the noise suppression effect of the noise filter is not diminished.

Further, the noise filter is isolated by the cooling fan guide and placed in this guide, so that it is sufficiently cooled.

[0009]

【Example】

 FIG. 1 shows the structure of a microwave oven according to an embodiment of the present invention. An electric equipment room 1 is formed on the right side of a heating room (not shown) for storing food. In the electrical equipment chamber 1, a magnetron 2 for supplying a high frequency to the heating chamber, a high voltage transformer 3 for applying a high voltage to the magnetron 2, and an inverter 4 for driving the magnetron 2 through the high voltage transformer 3 at a high frequency. A noise filter 6 which is provided in the front stage of the inverter 4 in a circuit and connected to an external power supply connecting cord 5 to suppress noise from the inverter 4 to the outside, and an intake hole (not shown) in a rear wall 7 of the electrical equipment chamber. A cooling fan 8 for sucking outside air from the outside and supplying cooling air to the magnetron 2, the high voltage transformer 3, the inverter 4 and the like is provided. Further, a cooling fan guide 9 made of a magnetic material, that is, an iron plate and surrounding the cooling fan 8 is provided, and the noise filter 6 is arranged in the guide 9.

As shown in the figure, the noise filter 6 is electromagnetically isolated from the high voltage transformer 3 by the cooling fan guide 9 made of a magnetic material, and is not affected by the leakage magnetic flux from the high voltage transformer. The noise suppression effect of the noise filter 6 does not decrease. However, the noise filter 6 is placed in the cooling fan guide 9 and is sufficiently cooled.

[0011]

[Effect of the device]

 According to the present invention, in the high-frequency heating device that drives the high-frequency supplying means by using the inverter, the noise suppression effect of the noise filter is affected by the leakage magnetic flux from the high-voltage transformer while ensuring the cooling of the noise filter. It can be prevented from decreasing.

[Brief description of drawings]

FIG. 1 is a side view of a microwave oven according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of a conventional microwave oven.

[Explanation of symbols]

 2 Magnetron 3 High-voltage transformer 4 Inverter 5 External power connection cord 6 Noise filter 8 Cooling fan 9 Cooling fan guide

Claims (1)

[Scope of utility model registration request] 1. A high-frequency supply means for supplying a high-frequency wave to a heating chamber containing food, a high-voltage transformer for applying a high voltage to the high-frequency supply means, and an inverter for driving the high-frequency supply means through the high-voltage transformer at a high frequency. For a cooling fan, which is composed of a noise filter connected to an external power supply connection cord, a cooling fan that supplies cooling air to the high frequency supply means, the high voltage transformer and the inverter, and a magnetic body, and electromagnetically isolates the noise filter from the high voltage transformer. High frequency heating device consisting of a guide.