BE1030947A1 - High frequency household appliance, preferably high frequency cooking appliance - Google Patents

Abstract

The invention relates to a high-frequency household appliance (1), preferably a high-frequency cooking appliance (1), with at least one treatment chamber (11) which is designed to accommodate an item to be treated with high-frequency energy, and with at least one high-frequency heating module (2) which is designed to generate the high-frequency energy and to deliver it to the treatment chamber (11), wherein the high-frequency heating module (2) has at least one high-frequency signal generator (21) which is designed and configured to generate high-frequency energy, wherein the high-frequency heating module (2) further has a high-frequency conductor (25) which is designed and configured to transmit the high-frequency energy from the high-frequency signal generator (21) to the treatment chamber (11). The high-frequency household appliance (1) is characterized in that the high-frequency signal generator (21) is designed as a circuit board (21), wherein the circuit board (21) has a first conductor (21a) on one side and a second conductor (21b) on the opposite side, which are each surrounded by air and together form an inner conductor (21a, 21b) of the high-frequency signal generator (21).

Description

Description

High frequency household appliance, preferably high frequency cooking appliance

The invention relates to a high-frequency household appliance and a high-frequency heating module for use in such a high-frequency household appliance.

It is known to heat materials using microwaves. Microwaves are electromagnetic waves with a frequency of about 1 GHz to about 300 GHz, i.e. with

Wavelengths from about 30 cm to about 1 mm. Microwaves can break molecules into

Stimulate vibrations and thereby increase the temperature of the molecules. This is used, for example, in microwave ovens to heat or cook food inside the cooking chamber.

A microwave oven, also called a microwave oven, usually has an outer casing with a cooking chamber inside. The cooking chamber is separated from the outside by a

Access opening accessible, which can be opened and closed by means of a door or a flap ı5. Outside are usually also

Display and control elements are provided to control, for example, the power and duration of the

process can be adjusted by a user. Between the outer casing and

A space is formed between the cooking chamber, in which usually at least one

Microwave generator is arranged, which can generate the microwaves and guide them through at least one corresponding high-frequency waveguide into the cooking chamber as a cavity. Originally, so-called magnetrons were used to generate the

Microwave radiation is used, so nowadays electronic circuits such as e.g.

Transistors are common for this purpose.

It is generally known to distinguish between the RF module (high frequency module) as

Microwave generator or high frequency heating module and the treatment room of the

microwave oven, a coaxial cable with appropriate coaxial connectors must be used to guide the HF energy (high frequency energy, high frequency heating energy or high frequency energy) to the interior. The coaxial cable can be designed together with an antenna, i.e. without any additional connectors, and can be mounted on the wall of the

The antenna can be a monopole type or an inverted type.

F-shaped antenna.

Alternatively, the HF energy can also be guided into the interior via an HF hollow line (high frequency hollow line) as an HF waveguide (high frequency waveguide).

Cross sections of waveguides can be rectangular or oval. The wall of the

Inside the building, the HF waves (high frequency waves) can run vertically through such waveguides and pass through a rectangular or oval window in the wall of the

interior, also called high-frequency windows, and enter the interior.

The applicant also knows a type of cooking appliance which is referred to as a “dialogue cooker”. A so-called dialogue cooker is based on known or conventional

Ovens that use an energy supply such as top and bottom heat or

Circulating air works so that a precisely set heat penetrates the food from the outside and slowly works its way into the food. This type of cooking, such as baking, therefore has such an effect on the food as

Cooking food means that the outer layers of the food are heated for a comparatively long time or strongly ı5, but the core of the food is heated for a comparatively short time or little, since the heat only spreads from the outer layers to the core of the food during the cooking process.

food must spread.

In order to speed up such cooking processes and/or to distribute the heat of the cooking process more evenly throughout the food, the further development of such conventional ovens to create dialog cookers is known, which additionally generate electromagnetic waves with changing frequencies in the high-frequency spectrum, i.e.

HF waves are used to heat only the food being cooked and not its surroundings or the ambient air. This can be done very precisely and in a very targeted manner with regard to the additional heat that is to be supplied to the food. This can lead to a significant acceleration of the cooking process and improve the quality of the result of the cooking process.

The invention addresses the problem of a high-frequency household appliance or a

High frequency heating module for a high frequency household appliance of the type described above

type so that the manufacturing and/or assembly costs can be reduced. In addition or alternatively, the most cost-effective and/or low-loss

HF lines (high frequency lines) and/or HF couplers (high frequency couplers) are to be created. This should be done especially for high frequency cooking appliances. At least an alternative to known high frequency household appliances or

High frequency heating modules can be created.

Thus, the invention relates to a high-frequency household appliance, preferably a

High frequency cooking appliance, with at least one treatment chamber, which is designed

to receive a product to be treated with high-frequency energy, and with at least one high-frequency heating module which is designed to generate the high-frequency energy and to deliver it into the treatment room, wherein the high-frequency heating module has at least one high-frequency signal generator which is designed and arranged to generate high-frequency energy, wherein the high-frequency heating module further has a high-frequency conductor which is designed and arranged to

To transmit high frequency energy from the high frequency signal generator to the treatment room.

The high-frequency household appliance is characterized in that the high-frequency

Signal generator is designed as a circuit board, wherein the circuit board has a first conductor on one side and a second conductor on the opposite side, which are each surrounded by air and together form an inner conductor of the

high frequency signal generator. The two conductors can each be designed as conductor tracks, which can simplify production and/or save installation space. In any case, an inner conductor of a stripline can also be created in this way to generate high frequency signals. The surrounding metallic elements of the

High frequency signal generators can serve as outer conductors, as will be described in more detail below.

Accordingly, a cavity filled with air can be created around the inner conductor of a stripline so that the ambient air can act as a dielectric. This can avoid the use of expensive and special dielectric material, which can accordingly reduce manufacturing and assembly costs.

The high-frequency lines can in particular be designed as conductor tracks.

According to one aspect of the invention, the conductors are arranged between a first solid

metal part and a second solid metal part. The two solid metal parts can be housing parts, which can thus be used not only as housing parts, but also as electrically conductive outer walls or as outer conductors of the high-frequency signal generator. This can save additional electrically conductive outer walls.

According to a further aspect of the invention, the second solid metal part forms solely an input section and an output section of the high-frequency conductor, which run parallel to each other, wherein the second solid metal part together with a

Closure element forms a central section of the high frequency conductor which is perpendicular to the input section and the output section of the high frequency

conductor. This can enable a compact design of the high-frequency conductor.

In particular, the second solid metal part can be made from one piece in this way and the open side of the middle section of the high-frequency conductor can then be

locking element.

According to a further aspect of the invention, the high-frequency heating module, preferably a first solid metal part and/or a second solid metal part, is designed to connect the air-filled environment of the conductors with the environment of the high-frequency

This can provide cooling of the conductors as the inner conductor of the

High frequency signal generator using natural or forced convection.

According to a further aspect of the invention, a high-frequency inner conductor part runs, preferably concentrically, within the high-frequency conductor. This can enable a possibility of the concrete implementation of a high-frequency line.

According to a further aspect of the invention, the circuit board has a contact element, preferably arranged concentrically, which is connected to the high-frequency

Inner conductor part is connected in an electrically conductive manner. This can enable an electrically conductive ı5 contact between the circuit board and the high-frequency inner conductor part.

According to a further aspect of the invention, the contact element has a contact pin and the high-frequency inner conductor part has a contact spring. This can be a concrete

Possibility of implementing such a contact. Alternatively, the contact element could be a contact spring and the high-frequency inner conductor part a

contact pin. This can represent an alternative concrete possibility for implementing such a contact.

According to a further aspect of the invention, the high-frequency inner conductor part is positioned, preferably concentrically, at least in a central section of the high-frequency conductor by means of at least one electrically non-conductive holding element. This can represent a possibility for implementing the positioning of the high-frequency conductor.

According to a further aspect of the invention, the high-frequency inner conductor part is in a

Output section of the high frequency conductor electrically conductive with the second massive

metal part. This can enable electrical contact there.

According to a further aspect of the invention, the first solid metal part is at the end of the

Input section of the high frequency conductor as, preferably concentric,

High-frequency test point and/or designed as a, preferably concentric, calibration interface, which is accessible in an assembly step of the high-frequency heating module.

This may make it possible to carry out such a test and/or

Calibration of the high frequency signal generator. This can be done in particular at a point on the high frequency heating module which is then no longer accessible. This can also create an additional high frequency test point and/or

Calibration interface can be avoided, which would cause additional effort and/or take up additional installation space. 5 According to a further aspect of the invention, the high-frequency test station and/or

Calibration interface is filled at least partially by means of a filling element in a subsequent assembly step. This can make it possible to use the high-frequency test point and/or calibration interface to carry out a test and/or

Calibration of the high frequency signal generator, but then the constructive

Formation of the second solid metal part as required for operation.

According to a further aspect of the invention, the first solid metal part of the

The circuit board has a plurality of cooling fins facing away from the circuit board. This can be a simple but effective way of dissipating heat from the circuit board. ı5 According to a further aspect of the invention, the circuit board has at least one further high-frequency element, preferably at least one high-frequency coupler element and/or a high-frequency field probe, on at least one side at the edge of the inner conductor. This allows further high-frequency elements to be installed in a space-saving manner and close to the

conductors of the inner conductor.

According to a further aspect of the invention, the area of the inner conductor of the circuit board is connected to the rest of the circuit board by means of at least one retaining web, preferably by means of a plurality of retaining webs, preferably arranged in a uniformly distributed manner, wherein the retaining web, preferably in the area of the strongest electric field, has a comparatively low mass, preferably by means of at least one constriction and/or by means of at least one through-opening. This can

Keep the influence of the circuit board on the electric field as low as possible.

The present invention also relates to a high-frequency heating module for use in a high-frequency household appliance as described above. This allows a

High frequency heating module can be provided to produce an inventive

To realize a high-frequency household appliance and to utilize its properties and advantages.

Microwaves have been used for heating for decades, especially at 915 MHz or 2450 MHz. In addition to the well-known microwave ovens in private and professional kitchens, there are numerous industrial applications in which microwaves and the corresponding high-frequency technology are used. The powerful

Microwaves are currently mostly generated using magnetrons, which

Vacuum electronic components (tubes).

The development of power semiconductors has progressed so far that it now seems possible and advantageous to build ovens or heaters in which the HF

Heating energy is generated using transistors.

It is an object of the invention to provide solutions for cost-effectively producible HF

Heating modules and/or for cost-effective and/or low-loss RF cables and/or RF couplers.

A typical household appliance, in particular an oven, comprises a treatment chamber, in particular a cooking chamber.

The household appliance according to the invention is a household appliance which is equipped with at least one HF heating module according to the invention. The HF heating module has at least one circuit board on which the HF heating energy is generated. The HF energy is

At least one HF line, which is built with the circuit board (circuit board HF line), is led towards the treatment room. The circuit board HF line can be of the type stripline, microstrip, inverted microstrip or suspended microstrip, for example.

A well-known state of the art is to install a

Coaxial cable with appropriate coaxial connectors to connect the RF

energy to the treatment room. The coaxial cable can be used together with a

Antenna, i.e. without any additional connectors, and attached to the treatment room wall. The antenna can be a monopole-type or an inverted-F-shaped antenna.

antenna.

The HF energy can also be fed into the treatment room via an HF waveguide. The usual cross-sections of waveguides are rectangular. However, many other cross-sections, particularly oval ones, are possible. In the treatment room wall, the HF waves will run vertically via such waveguides and pass through a rectangular or oval window, for example.

As already mentioned, RF lines on printed circuit boards are usually of the “microstrip” type. Often, special base material with low dielectric losses and well-specified

permeability, which is relatively expensive.

This invention proposes to provide an RF

A stripline cable can be used as follows: The electrically conductive outer wall of the

Stripline will be realized with the metallic housing parts base and cover.

The inner conductor of the stripline is built with conductor tracks on the top and bottom of the circuit board. The area around these conductor tracks is milled free so that almost everywhere around the

A cavity (with air) is created around the inner conductor, except for a few places where

Retaining bars remain which hold the inner conductor in position.

The RF wave fields essentially only penetrate air and thus there are very few dielectric losses and a low-loss RF line can be built without the use of expensive circuit board base material.

Furthermore, it is advantageous and easy to install RF

To manufacture layout elements, in particular RF coupler elements or RF field probes.

These can then be connected easily and advantageously to other circuit parts on the circuit board. ı5 Holding bridges are preferably thinned out, especially where the electric field can be strongest, preferably with holes. Optionally, the cavity around the

The inner conductor is traversed by cooling air (by natural convection or by forced

Flow).

An embodiment of the invention is shown purely schematically in the drawings

And is described in more detail below. It shows

Figure 1 is a schematic representation of a high frequency

household appliance; and

Figure 2 is a sectional view through a high frequency

Heating module in the installed state in the inventive high-frequency

household appliance.

A high-frequency household appliance 1 according to the invention is illustrated using the example of a high-frequency

Cooking appliance 1 is considered, which can be, for example, a microwave oven 1, a microwave oven 1 or a dialogue cooker 1, see Figure 1. The high-frequency cooking appliance 1 has a

Outer casing 10 which encloses and protects the components of the high frequency cooking device 1. Inside the high frequency cooking device 1 is a

Treatment chamber 11 is provided, which is enclosed or formed by a wall 12. Between the outer housing 10 and the wall 12 of the treatment chamber 11, a space 13 is formed, which contains the electrical and electronic

Components of the high-frequency cooking appliance 1. The treatment chamber 11 can be closed by opening a closure element (not shown), for example in the form of a

Door or flap can be made accessible and closed.

In the treatment room 11, which can also be referred to as the interior 11, the cooking chamber 11 or the cavity 11, a cooking process of the high-frequency cooking device 1 can be carried out. For this purpose, a person as the user can place a food item as a cooking item or as a product to be treated into the treatment room 11 with the closure element open and the treatment room 11 can then be closed to the outside by closing the closure element. The cooking process can be carried out solely by the energy of high-frequency electromagnetic waves or in addition to, for example, circulating air.

In any case, the high-frequency energy in the form of high-frequency electromagnetic waves is generated by a high-frequency heating module 2 of the high-frequency

cooking appliance 1, which is arranged in the space 13, see Figure 2. The

High frequency heating module 2 has a high frequency signal generator 21, which is designed to generate the high frequency energy for the treatment room 11. The

High frequency signal generator 21 is designed as a circuit board 21. The circuit board 21 is flat between a first solid metal part 20, which can also be referred to as metal base 20, and a second solid metal part 23, which can also be referred to as

Metal top part 23 or lid 23. The first solid

The metal base part 20 has several cooling fins 20a facing away from the circuit board 21 and pointing outwards, which is why the first solid metal part 20 can also be referred to as a heat sink 20.

The high frequency signal generator 21 or the circuit board 21 is designed such that the

Circuit board 21 has on one side a first, lower conductor 21a and on the opposite side a second, upper conductor 21b, which are each surrounded by air and together form an inner conductor 21a, 21b of the high-frequency

signal generator 21. For this purpose, the adjacent areas of the two massive

Metal parts 20, 23 are milled out accordingly to form the surrounding air space (not designated). The two solid metal parts 20, 23 thus form a

Outer conductors 20, 23 of the high frequency signal generator 21. In this way,

Air can be used instead of a special dielectric, which reduces costs and

The two conductors 21a, 21b together with the two solid metal parts 20, 23 form a stripline as electrically conductive outer walls.

In order to guide the high-frequency energy of the high-frequency signal generator 21 or the circuit board 21 or its high-frequency lines 21a, 21b to the treatment room 11, the first solid metal part 20 and a closure element 27a in the form of a

A high-frequency conductor 25 is formed on the sheet metal cover 27a, which can also be referred to as a high-frequency path 25. The high-frequency conductor 25 is connected to the second, upper

High frequency lines 21b of the circuit board 21 opposite end via a

High frequency window 28 is connected to a corresponding high frequency waveguide 14 of the high frequency cooking appliance 1 by means of connecting elements 14a in the form of screws 14a, see Figure 1.

The high-frequency conductor 25 is divided along the propagation direction of the generated electromagnetic waves into an input section 25a, a middle section 25b and an output section 25c, which ends with the high-frequency window 28.

The input section 25a of the high-frequency conductor 25 points vertically away from the second, upper high-frequency lines 21b of the circuit board 21 and is completely formed or enclosed by the second solid metal part 23. In this area, a

Contact element 22 with a contact pin 22a on the second, upper high-frequency

Lines 21b of the circuit board 21 are arranged, which is arranged centrally on the circuit board 21 and points vertically upwards from the circuit board 21 into the input section 25a. A high-frequency inner conductor part 26 is connected in a resilient and electrically conductive manner by means of a contact spring 26a which surrounds the contact pin 22a of the circuit board 21.

The high-frequency inner conductor part 26 thus runs concentrically in the input section 25a of the high-frequency conductor 25 to its inner wall (not designated), which is formed by the second

Solid metal part 23 is formed.

The edge of the second solid metal part 23 or its transition into the middle section 25b of the high-frequency conductor 25 is designed in such a way that a concentric high-frequency test point 23a or a concentric calibration interface 23a is formed there in an intermediate step during assembly, so that a test device can be attached there by means of a concentric connector using a contact spring in order to carry out a test or calibration. During assembly, the

Edge of the second solid metal part 23 is filled to the remaining contour of the second solid metal part 23 by means of a metallic filling element 23b.

The middle section 25b of the high-frequency conductor 25 is connected at a right angle to the input section 25a of the high-frequency conductor 25, so that the electromagnetic waves in this area can be guided parallel to the treatment chamber 11, which saves space. The high-frequency inner conductor part 26 also runs at a right angle and concentrically. One side of the middle section 25b of the high-frequency conductor 25 is formed by the aforementioned closure element 27a or sheet metal cover 27a. The other sides of the middle section 25b of the high-frequency conductor 25 are formed by the first solid metal part 20. The high-frequency inner conductor part 26 is concentrically aligned and held by means of an electrically non-conductive holding element 24.

The output section 25c of the high-frequency conductor 25 is connected at right angles to the middle section 25b of the high-frequency conductor 25, so that the electromagnetic waves

In this area towards the treatment room 11 or the high-frequency waveguide 14 of the

high frequency cooking device 14. The output section 25c of the

High frequency conductor 25 is formed by the first solid metal part 20. The high frequency

Inner conductor part 26 also runs concentrically in the output section 25c of the high-frequency conductor 25 and is connected to the second, upper high-frequency lines 21b of the

Circuit board 21 opposite end with the inner wall (not marked) of the

Output section 25c of the high frequency conductor 25 is electrically conductively connected.

List of reference symbols (part of the description) 1 high-frequency household appliance; high-frequency cooking appliance; microwave oven;

Microwave oven; dialog cooker 10 Outer casing 11 Treatment chamber; interior; cooking chamber; cavity 12 Wall of the treatment chamber 11 13 Intermediate space 14 High-frequency waveguide 14a Connecting elements; screws 2 High-frequency heating module 20, 23 Outer conductor of the high-frequency signal generator 21 20 First solid metal part; metal base; heat sink 20a Cooling fins of the metal base 20 21 High-frequency signal generator; circuit board 21a, 21b Inner conductor of the high-frequency signal generator 21 21a First, lower conductor or first, lower conductor track 21b Second, upper conductor or second, upper conductor track 22 Contact element 22a Contact pin of the contact element 22 23 Second solid metal part; metal top; cover 23a (concentric) high-frequency test point; (concentric) calibration interface 23b Filling element 24 Holding element 25 High frequency conductor; high frequency path 25a Input section of the high frequency conductor 25 25b Middle section of the high frequency conductor 25 25c Output section of the high frequency conductor 25 26 High frequency inner conductor part 26a Contact spring of the high frequency inner conductor part 26 27a Closure element of the high frequency conductor 25; metal cover 28 High frequency window

Claims (15)

Patent claims 1. High-frequency household appliance (1), preferably high-frequency cooking appliance (1), with at least one treatment chamber (11) which is designed to accommodate an item to be treated with high-frequency energy, and with at least one high-frequency heating module (2) which is designed to generate the high-frequency energy and to deliver it into the treatment chamber (11), wherein the high-frequency heating module (2) has at least one high-frequency signal generator (21) which is designed and configured to generate high-frequency energy, wherein the high-frequency heating module (2) further has a high-frequency conductor (25) which is designed and configured to transmit the high-frequency energy from the high-frequency signal generator (21) to the treatment chamber (11), characterized in that the high-frequency signal generator (21) is designed as a circuit board (21), wherein the circuit board (21) has a first conductor (21a) on one side and a second conductor (21b) on the opposite side, which are each surrounded by air and together form an inner conductor (21a, 21b) of the high-frequency signal generator (21). 2. High-frequency household appliance (1) according to claim 1, wherein the conductors (21a, 21b) are arranged between a first solid metal part (20) and a second solid metal part (23). 3. High-frequency household appliance (1) according to claim 2, wherein the second solid metal part (23) alone forms an input section (25a) and an output section (25c) of the high-frequency conductor (25), which run parallel to one another, and wherein the second solid metal part (23) together with a closure element (27a) forms a middle section (25b) of the high-frequency conductor (25), which runs at right angles to the input section (25a) and the output section (25c) of the high-frequency conductor (25). 4. High-frequency household appliance (1) according to one of the preceding claims, wherein the high-frequency heating module (2), preferably a first solid metal part (20) and/or a second solid metal part (23), is designed to connect the air-filled environment of the conductors (21a, 21b) with the environment of the high-frequency heating module (2) in an air-flow manner. 5. High-frequency domestic appliance (1) according to one of the preceding claims, wherein a high-frequency inner conductor part (26) runs, preferably concentrically, within the high-frequency conductor (25). 6. High-frequency household appliance (1) according to claim 5, wherein the circuit board (21) has a preferably concentrically arranged contact element (22) which is electrically conductively connected to the high-frequency inner conductor part (26). 7. High-frequency household appliance (1) according to claim 6, wherein the contact element (22) has a contact pin (22a) and the high-frequency inner conductor part (26) has a contact spring (26a). 8. High-frequency domestic appliance (1) according to one of claims 5 to 7, wherein the high-frequency inner conductor part (26) is positioned, preferably concentrically, at least in a central section (25b) of the high-frequency conductor (25) by means of at least one electrically non-conductive holding element (24). 9. High-frequency household appliance (1) according to one of claims 5 to 8, wherein the high-frequency inner conductor part (26) is electrically conductively connected to the second solid metal part (23) in an output section (25c) of the high-frequency conductor (25). 10. High-frequency household appliance (1) according to one of the preceding claims, wherein the first solid metal part (20) at the end of the input section (25a) of the high-frequency conductor (25) is designed as a, preferably concentric, high-frequency test point (23a) and/or as a, preferably concentric, calibration interface (23a), which is accessible in an assembly step of the high-frequency heating module (2). 11. High-frequency household appliance (1) according to claim 10, wherein the high-frequency test point (23a) and/or calibration interface (23a) is filled at least in sections by means of a filling element (23b) in a subsequent assembly step. 12. High-frequency household appliance (1) according to one of the preceding claims, wherein the first solid metal part (20) facing away from the circuit board (21) has a plurality of cooling fins (20). 13. High-frequency household appliance (1) according to one of the preceding claims, wherein the circuit board (21) has at least one further high-frequency element, preferably at least one high-frequency coupler element and/or one high-frequency field probe, on at least one side at the edge of the inner conductor (21a, 21b). 14. High-frequency domestic appliance (1) according to one of the preceding claims, wherein the region of the inner conductor (21a, 21b) of the circuit board (21) is connected to the rest of the circuit board (21) by means of at least one retaining web, preferably by means of a plurality of retaining webs, preferably arranged in a uniformly distributed manner, wherein the retaining web, preferably in the region of the strongest electric field, has a comparatively low mass, preferably by means of at least one constriction and/or by means of at least one through-opening. 15. High-frequency heating module (2) for use in a high-frequency household appliance (1) according to one of the preceding claims.