BE1030943B1 - 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) which is arranged between a first solid metal part (20) and a second solid metal part (23), wherein the second solid metal part (23) forms at least in sections an input section (25a) of the high-frequency conductor (25).

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, which can be opened and closed by means of a door or flap, for example. Outside, ı5 display and control elements are usually provided, for example to control the power and the 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.

The RF energy can alternatively be transmitted via an RF waveguide (high frequency waveguide) as

RF waveguides (high frequency waveguides) are introduced into the interior. Usual

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 via 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 “dialog cooker”. A so-called dialog 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, while 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

Artto create so that the manufacturing and/or assembly costs can be reduced. In particular, the manufacturing and/or assembly costs of the HF-

Waveguide of the high-frequency heating module can be reduced. This should be done especially for high-frequency cooking devices. At least an alternative to known high-frequency household appliances or high-frequency heating modules should be created.

According to the invention, this problem is solved by a high-frequency household appliance and by a high-frequency heating module having the features of the independent patent claims.

Advantageous embodiments and further developments of the invention emerge from the following subclaims.

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 emit it into the treatment chamber, wherein the high-frequency heating module has at least one high-frequency signal generator, which is designed and configured to generate high-frequency energy, wherein the high-frequency heating module further has a high-frequency conductor, which is designed and configured to

High frequency energy from the high frequency signal generator to the treatment room

Transmitted.

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

Signal generator is designed as a circuit board, which is located between a first solid

metal part and a second solid metal part, wherein the second solid

Metal part forms an input section of the high-frequency conductor at least in sections. This makes it possible to generate a high-frequency signal, which can also be relatively easy to manufacture and/or assemble.

According to one aspect of the invention, the second solid metal part solely forms the

Input section and an output section of the high frequency conductor, which run parallel to each other, and the second solid metal part forms together with a

Closure element has a middle section of the high-frequency conductor, which runs at right angles 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 closed by the closure element.

According to a further aspect of the invention, the second solid metal part partially forms the input section of the high-frequency conductor and a waveguide element partially forms the input section of the high-frequency conductor and solely a

middle section and an output section of the high frequency conductor, wherein the

Middle section of the high frequency conductor perpendicular to the input section and the

output section of the high frequency conductor. This can enable an alternative implementation of the properties and advantages described above.

According to a further aspect of the invention, a high-frequency inner conductor part runs, preferably concentrically, within the high-frequency conductor. This can be a

Enable the possibility of 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 electrically conductively connected. This can be an electrically conductive

Enable 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 contact.

According to a further aspect of the invention, the contact element has a contact spring and the high-frequency inner conductor part has 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. ı5 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 should be avoided, which would cause additional effort and/or take up additional installation space.

According to a further aspect of the invention, the high frequency test station and/or

Calibration interface in a subsequent assembly step at least in sections

Filled in using a filling element. This can enable the high frequency test point and/or calibration interface to perform 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

Aside from the circuit board, it has a number of cooling fins. This can be a simple but effective way to remove heat from the circuit board.

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.

In other words, 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 with 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 RF

Heating energy is generated using transistors.

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

Heating modules, for HF heating modules that can be cost-effectively mounted in a household appliance and/or

Or for RF waveguide designs that can be manufactured and assembled cost-effectively.

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 guided towards the treatment room on at least one HF line which is constructed with the circuit board (circuit board HF line). The circuit board HF line can be of the stripline, microstrip, inverted microstrip or suspended microstrip type, 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. Common waveguide cross-sections 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.

According to the invention, printed circuit boards with contact pins on a metal base with

Cooling fins or a heat sink. At least one cover with cavities for HF

Cables or RF functions (e.g. RF filters or waveguide transitions) are mounted.

Preferably, the cover is made in one piece from one material. Optionally, in this partially assembled state, an RF test or a

Calibration interface available. Preferably this interface is of the coaxial type.

Preferably, the interface conforms to or is similar to a standard for coaxial connectors.

Preferably, the test device side has a contact spring.

After optional testing or calibration, the following is assembled: e HF inner conductor parts (preferably with contact spring) e “gap filler” parts if necessary e holding parts for inner conductor parts if necessary e sheet metal cover (preferably flat and thin)

The inner conductor part is preferably part of a stripline. It can also be part of an RF

filter structure. Near the RF wave windows, the inner conductor part forms a

Transition to a hollow pipe.

A “gap filler” part can be used to fill parts of the cavities with metal that are required for the

Testing or calibration in the partially assembled state of the test device and its connector are required, but would be a hindrance to further RF wave transmission, since, to put it bluntly, the RF outer wall currents would otherwise have to flow unnecessarily or inconveniently long detours.

Preferably, RF conductors, filters and transitions are made of stamped sheet metal.

Alternatively, the contact springs are placed on the circuit boards and the contact pins on the

Inner conductor parts are built. On the test device side, corresponding contact pins are then available.

Instead of using contact springs, the electrical contact between the metal parts can also be made using screws.

It is also possible to solder threaded rivets onto the circuit board, which can be used to attach further

Contact elements are attached to the circuit board to establish electrical contact.

The construction is advantageously designed in such a way that all screws are aligned in the same way, allowing easy assembly with only one screwing and joining direction.

Optionally, the cover can be fitted with spring contacts that are electrically connected to the

circuit board, plugged in and thus electrically connected to the circuit board.

Optionally, flexible RF sealing material is used on contact surfaces between heat sink,

Circuit board and cover used to provide electrical contact and RF between the parts

To ensure tightness.

For installation in HF household appliances such as ovens, the HF heating module with its

HF wave window mounted on a corresponding window in the oven. This can be done with

screws. Under this window, the RF waves are transmitted in metal-coated

Cavities or hollow pipes to the cooking chamber. Simple, inexpensively manufactured sheet metal parts are preferably used for this purpose.

Alternatively, the invention can also be implemented using a smaller solid part and a larger (deep-drawn) sheet metal part. The sheet metal part can be connected to the cooking chamber using screws, rivets or clamps. By punching or perforating the

Sheet metal can reduce disturbing heat conduction in the sheet metal. An inner conductor holding part (made of

Plastic) can also prevent heat convection. Preferably, these

Measures implemented in areas where the RF cable has a small cross-section.

Several embodiments of the invention are shown purely schematically in the drawings and are described in more detail below. It shows

Figure 1 is a schematic representation of a high frequency

household appliance;

Figure 2 is a sectional view through a high-frequency heating module according to a first embodiment;

Figure 3 is a sectional view of the high frequency heating module according to the first

Embodiment of Figure 2 in the installed state in the high-frequency household appliance according to the invention;

Figure 4 is a sectional view through a high-frequency heating module according to a second embodiment

Figure 5 is a sectional view of a high frequency heating module according to the third

Embodiment 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, an intermediate 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 intermediate space 13, see Figures 2 and 3 for the first embodiment, Figure 4 for the second embodiment and Figure 5 for the third embodiment.

According to the first embodiment of Figures 2 and 3, 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 a metal lower part 20, and a second solid metal part 23, which can also be referred to as a metal upper part 23 or as

Cover 23 is arranged. The first solid 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.

In order to guide the high-frequency energy of the high-frequency signal generator 21 or the circuit board 21 to the treatment room 11, a high-frequency conductor 25 is formed by the first solid metal part 20 and a closure element 27a in the form of a sheet metal cover 27a, which can also be referred to as a high-frequency path 25. The

High frequency conductor 25 is connected at its end opposite the circuit board 21 via a

High frequency window 28 with 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 3.

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

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

In this area there is also a contact element 22 with a contact pin 22a on the

Circuit board 21, which is arranged centrally on the circuit board 21 and from the

Printed circuit board 21 points vertically upwards 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.

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

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 a right angle to the middle section 25b of the high-frequency conductor 25, so that the electromagnetic waves in this area are directed towards the treatment room 11 or towards 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 at its end opposite the circuit board 21 to the

Inner wall (not designated) of the output section 25c of the high frequency conductor 25 is electrically conductively connected.

The second embodiment of Figure 4 differs from the first only in that

Embodiment of Figures 2 and 3 that in the high-frequency heating module 2 of the second embodiment of Figure 4, the contact element 22 has a contact spring 22b and the high-frequency inner conductor part 26 has a contact pin 26b.

In the third embodiment of Figure 5, the first solid metal part 20 ends somewhat at the level of the contact element 22, which, as in the second embodiment of the

Figure 4 has a contact spring 22b. There is a waveguide element 27b which is connected to the first solid metal part 20 by means of connecting elements 29 in the form of screws 29. The waveguide element 27b thus forms the

High frequency conductor 25 with input section 25a, middle section 25b and

Exit section 25c.

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 First solid metal part; Metal base; Cooling element 20a Cooling fins of the metal base 20 21 High-frequency signal generator; Circuit board ı5 22 Contact element 22a Contact pin of the contact element 22 22b Contact spring of the contact element 22 23 Second solid metal part; Metal top; Cover 23a (concentric) high-frequency test point; (concentric) calibration interface 20 23b Filling element 24 Holding element

High frequency conductor; high frequency path 25a Input section of the high frequency conductor 25 25b Middle section of the high frequency conductor 25 25 2bc 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 26b Contact pin of the high frequency inner conductor part 26 27a Closure element of the high frequency conductor 25; Sheet metal cover 27b Waveguide element 28 High frequency window 29 Connecting elements; Screws

Claims (13)

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) which is arranged between a first solid metal part (20) and a second solid metal part (23), wherein the second solid metal part (23) has at least in sections an input section (25a) of the high frequency conductor (25). 2. High-frequency household appliance (1) according to claim 1, wherein the second solid metal part (23) alone forms the 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). 3. High-frequency household appliance (1) according to claim 1, wherein the second solid metal part (23) partially forms the input section (25a) of the high-frequency conductor (25) and wherein a waveguide element (27b) partially forms the input section (25a) of the high-frequency conductor (25) and solely a middle section (25b) and an output section (25c) of the high-frequency conductor (25), wherein the middle section (25b) of the high-frequency conductor (25) 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 a high-frequency inner conductor part (26) runs, preferably concentrically, within the high-frequency conductor (25). 5. High-frequency household appliance (1) according to claim 4, 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). 6. High-frequency household appliance (1) according to claim 5, wherein the contact element (22) has a contact pin (22a) and the high-frequency inner conductor part (26) has a contact spring (26a). 7. High-frequency household appliance (1) according to claim 5, wherein the contact element (22) has a contact spring (22b) and the high-frequency inner conductor part (26) has a contact pin (26b). 8. High-frequency domestic appliance (1) according to one of claims 4 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 domestic appliance (1) according to one of claims 4 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 heating module (2) for use in a high-frequency household appliance (1) according to one of the preceding claims.