Domestic microwave device with rotary antenna

Abstract

The invention relates to a domestic microwave device (1) having a rotary antenna (2) with at least two wings (3, 4) rotatable about a common rotation axis (R), wherein a relative angle (Th) between at least two of these wings (3, 4) is adjustable in motor-driven fashion about the rotation axis (R). The invention also relates to a method for operating a domestic microwave device (1) which is equipped with a rotary antenna (2) having at least two wings (3, 4), wherein, during operation of the domestic microwave device (1), a relative angle (Th) between at least two of the wings (3, 4) is adjusted in motor-driven fashion. The invention is particularly advantageously applicable to cooking appliances having a microwave function.

Description

[0001] The invention relates to a household microwave oven comprising a rotating antenna with at least two blades rotatable about a common axis of rotation. The invention also relates to a method for operating a household microwave oven equipped with a rotating antenna having at least two blades. The invention is particularly advantageously applicable to microwave ovens.

[0002] US 7,145,119 B1 discloses a microwave oven comprising a housing with a cooking chamber, a microwave source for generating microwaves, a waveguide for directing the microwaves generated by the microwave source into the cooking chamber, a rotating antenna rotatable by a drive motor for emitting the microwaves guided in the waveguide into the cooking chamber, and a movable stirrer coupled to the rotating antenna to cooperate with the rotating antenna.

[0003] EP 3 177 109 A1 discloses a microwave oven, in particular for a household appliance. The microwave oven has a cooking chamber that is at least partially enclosed by a cooking chamber wall. The microwave oven includes a microwave generator, in particular a magnetron, which is arranged outside the oven cavity. At least one antenna extension is arranged inside the cooking chamber. The antenna extension penetrates an opening in the cooking chamber wall. The antenna extension is electrically connected to the magnetron antenna.

[0004] CN 206004937 U discloses an antenna module and a microwave oven, wherein the antenna module comprises: a base plate, a first antenna pole attached to the base plate. Through the first antenna pole, an at least one second antenna pole extends in the axial direction, wherein the at least one second antenna pole is attached to the base plate, one end of which passes through the base plate and a semiconductor microwave source, and the other end of each second antenna pole is electrically connected.

[0005] WO 2012 / 114369 A1 discloses a high-frequency heating device capable of radiating high-frequency waves oscillated by a high-frequency oscillator more uniformly into a heating chamber. An antenna of the high-frequency heating device is equipped with: slotted antennas utilizing slot openings created on conductor sections as first radiating sections connected to an antenna shaft; conductor paths branching from the first radiating sections; and a second antenna utilizing an antenna plate connected to the conductor paths as a second radiating section.

[0006] CN 105509108 A discloses a microwave oven for cooking food. The microwave oven comprises a housing, a cylindrical oven chamber arranged within the housing, an electrical appliance chamber, a magnetron, an L-shaped waveguide tube with a vertical waveguide tube and a horizontal rectangular waveguide tube with a waveguide outlet, a helical antenna, a microwave reflector, a power supply, a fan, a circuit board, an oven door, and a circuit board equipped with a control knob, wherein the magnetron and the L-shaped waveguide tube are arranged in the electrical appliance chamber. The microwave oven utilizes a cylindrical oven chamber, thus eliminating eight useless energy storage dead zones of conventional rectangular oven chambers. The circularly polarized helical antenna is used as a microwave radiator, with one rotational speed of the helical antenna corresponding to one operating frequency of the magnetron.

[0007] DE 10 2014 109 730 A1 discloses a household appliance, in particular a cooking appliance, comprising a microwave source, a treatment chamber, and a distribution device for the directed distribution of microwave radiation in the treatment chamber. The distribution device for transmitting the microwave radiation into the treatment chamber has at least one transmitting device with at least one rotationally symmetrical outer surface.

[0008] EP 0 166 622 B1 discloses a microwave heater for heating a material in a heating chamber by means of microwave radiation generated by a microwave oscillator, comprising an external waveguide for directing the microwave radiation from the microwave oscillator into the heating chamber, the external waveguide having an outlet to the heating chamber at one of its ends, and a reflector device arranged near the outlet of the external waveguide for distributing the microwave radiation in the heating chamber, the reflector device comprising a rotating reflector part rotatable about the axis of the outlet of the external waveguide, characterized in that the reflector device has one or more reflective surfaces inclined to the axis of the outlet for reflecting the microwave radiation, and the heater comprises a drive device for rotating the reflector device, such thatthat the direction of reflection of the microwave radiation into the chamber is variable, leading to irregular reflection and uniform distribution of the microwaves within the chamber.

[0009] Microwave ovens with separately arranged and driven rotating antennas are also known, whereby the angular position of the rotating antennas can be individually adjusted.

[0010] JP 2011 202868 A (TOSHIBA CORP; TOSHIBA CONSUMER ELECTRONICS HOLDINGS CORP ET AL.) October 13, 2011 (2011-10-13) describes a household microwave oven comprising a rotating antenna with at least two vanes rotatable about a common axis of rotation (R).

[0011] It is the Task The present invention aims to overcome the disadvantages of the prior art, at least in part, and in particular to provide a compact and structurally simple way to adjust microwave distribution in a cooking chamber in a variety of ways.

[0012] This problem is solved according to the features of the independent claims. Advantageous embodiments are the subject of the dependent claims, the description, and the drawings.

[0013] The problem is solved by a household microwave oven comprising a rotating antenna with at least two wings (also called blades) rotatable about a common axis of rotation, wherein a relative angle between at least two of these wings about the common axis of rotation is adjustable by a motor.

[0014] This offers the advantage that, with minimal design effort and space requirements, a large number of microwave field distributions can be selectively generated and activated within the cooking chamber of a household microwave oven. This, in turn, allows for either high uniformity or, alternatively, targeted unevenness when heating food. The large number of different adjustable field distributions is particularly advantageous when specific sequences of field distributions or antenna positions are selected to generate desired heating patterns. The present rotating antenna is therefore motor-driven and adjustable in such a way that the angular position of its blades in space (especially in relation to the cooking chamber) as well as the relative angular position of at least two blades to each other can be set.

[0015] A household microwave oven can be a cooking appliance, a dish sanitizer, etc. If the household microwave oven is a cooking appliance, it can be a conventional oven, a standalone microwave oven, or a combination of both, such as an oven with a microwave function or a microwave oven with additional infrared emitters.

[0016] It is a further development that a household microwave oven has a treatment chamber, which can be sealed by means of a microwave-proof door and is susceptible to microwaves. The microwaves are generated by a microwave generator, which can be, for example, a magnetron or a semiconductor-based microwave generator. In a further development, the microwave generator has an inverter or is an inverter-controlled microwave generator. In the case of a cooking appliance, the treatment chamber can also be referred to as the cooking chamber.

[0017] The microwaves are coupled into the treatment room using a rotating antenna, with the field distribution of the microwaves within the treatment room being largely determined by the angular position of its respective vanes. In particular, the field distribution can be adjusted or set by selecting the angular position(s). For this purpose, the vanes are typically designed to be electrically conductive, for example, by being at least partially made of an electrically conductive material such as metal or electrically conductive ceramic.

[0018] It is a further development step that the microwave generator is connected to the rotating antenna via a microwave guide. The microwaves generated by the microwave generator are guided to the rotating antenna via the microwave guide, from where they are coupled out towards the treatment room. The microwave guide can, for example, be a waveguide.

[0019] It is a further development that at least one of the vanes of the rotating antenna is microwave-connected to the waveguide. This allows the microwaves present in the waveguide to be directed to this vane (which can also be described as energy or power coupling). It is a further development that all vanes of the rotating antenna are microwave-connected to the waveguide. It is a further development that at least one of the vanes is not microwave-connected to the waveguide or is microwave-isolated from it. A microwave connection between the microwave guide and a vane can be implemented by connecting the vane to an electrical conductor that extends into or protrudes from the microwave guide.

[0020] It is a further development step that at least two wings are electrically connected to each other. They are then also microwave-connected.

[0021] It is a further development requirement that at least two wings are electrically separated or isolated from each other. They can then also be separated from each other microwave-wise or – e.g., through capacitive coupling – microwave-wise connected to each other.

[0022] A wing can have virtually any shape. For example, at least one wing can be a simple circular segment, a circular segment with cutout(s), a rod, or a curved shape. A wing can be a single wing or a multiple wing (e.g., a double wing with two wing elements or wing sections, etc.). In particular, all wing elements or wing sections located on a common, rotatable wing axis can be considered parts of a single wing.

[0023] An axis of rotation is defined, in particular, as an imaginary straight line that defines or describes a rotation. A relative angular position or relative angle can be understood, in particular, as an angular distance or difference angle between at least two blades about the common axis of rotation. An absolute angular position or absolute angle of the rotating antenna can be understood as an angular position of any, but then fixed, blade relative to the cooking chamber, or as an angular position of an off-center blade axis relative to the common axis of rotation.

[0024] A feature of the invention is that each of the wings is connected to a drive motor via a respective axle or shaft (hereinafter referred to as a "wing axle") to enable its rotation. The drive motor can be an electric motor, for example, a stepper motor. Generally, each wing axle can be assigned its own drive motor. Alternatively, several wing axles can be driven by the same motor.

[0025] The wing axes can run at least partially through the microwave guide. They can be rotatably mounted on the microwave guide.

[0026] One design features a rotating antenna with exactly two blades. This advantageously allows for a wide range of field distribution adjustments within the treatment room with minimal structural complexity. However, the rotating antenna can also have three or more blades that can be adjusted relative to each other.

[0027] This embodiment features at least two wings, or their axes, that are rotatable independently of one another. This offers the advantage of highly versatile adjustment of both the absolute and relative angles of the wings. A further development, particularly advantageous for this embodiment, is that each of the movable wings is rotatable by its own motor.

[0028] One embodiment involves at least two wings having coaxially arranged wing axes or being rotatable via coaxially arranged wing axes. This allows for a particularly simple and compact design, especially when the rotating antenna has exactly two wings. A further embodiment involves a first straight wing axis of a first wing being rotatably arranged coaxially within a second straight wing axis of a second wing, which is designed as a tube or sleeve. In another embodiment, the two wing axes can be rotatable independently of each other.

[0029] This design involves the wing axes of two wings being rotatably connected to each other via a rotary ratchet mechanism (also known as a locking mechanism or pawl mechanism). The rotary ratchet ensures that when one motor-driven wing axis (drive axis) rotates in a first direction, the other wing axis rotates along with it, particularly at the same rate or angular velocity. However, if the driven wing axis rotates in the opposite direction, its rotational movement is not transferred to the other wing axis. The use of a rotary ratchet offers the advantage that the position of both wings in space and their relative angle to each other can be adjusted by driving only one of the wing axes. In other words, the absolute and relative angular position of both wings can be easily adjusted using just one drive motor.It is fundamentally irrelevant which of the two wing axes is the driving axis and which is the driven axis. Thus, in a coaxial arrangement of the wing axes, either the outer or the inner wing axis can be configured as the driving axis.

[0030] This design allows at least two blades or blade axes to be rotatable or driven by the same motor via a gearbox. This offers the advantage that multiple blades can be driven by a single motor and, depending on the gearbox design, for example its axis-dependent gear ratio, can also be rotated at different angular velocities.

[0031] This design incorporates a stop for one wing against another. This achieves the advantage of bringing the two wings into at least mechanical contact. This, in turn, allows for a particularly precise mechanical definition or adjustment of a specific relative angle (hereinafter also referred to as the zero, park, or rest position) between the two wings.

[0032] In a further development, the stop can advantageously be used to set an absolute angular position of the wings relative to the cooking chamber and a relative angular position of the wings to each other (i.e., the relative angle) using a single motor or a single driven wing shaft or wing. This is because, when the other wing is in stop position with the driven wing, it can be moved along with the driven wing, while by subsequently rotating the driven wing in the opposite direction, the relative angle between the two wings can be adjusted. However, the stop can also be provided for two independently driven wings.

[0033] A further advantage of providing a stop can be the electrical contact between the two wings, if the stop establishes an electrical connection between them. For this purpose, it can be designed as an electrically conductive stop. This has the advantage of preventing sparking between the two wings, which are typically located in close proximity to each other. This is particularly advantageous when the rotating antenna, with the wings in their parked position, is used to transmit high microwave power into the cooking chamber.

[0034] It is a further development that at least two of the mutually adjustable wings, specifically all wings, are spaced apart or "stacked" along the axis of rotation. This achieves the advantage that a particularly diverse field distribution can be set in the cooking chamber with a compact design of the rotating antenna, and furthermore, it can be easily ensured that the wings do not unintentionally block each other in their rotation.

[0035] One embodiment allows the height of at least two wings to be adjusted by a motor along the axis of rotation. This advantageously provides an additional parameter for varying the field distribution within the cooking chamber, while advantageously maintaining a compact design for the rotating antenna. Another embodiment allows, additionally or alternatively, the distance between at least two wings along the axis of rotation to be adjusted by a motor. This enables a particularly wide range of variations in the field distribution within the cooking chamber.

[0036] In this embodiment, the rotating antenna has two blades with coaxially arranged blade axes, each blade having an electrically conductive section microwave-connected to the blades, which projects into a portion of a microwave guide. The electrically conductive section of the outer blade axis serves as a lateral shield for a corresponding electrically conductive section of the inner blade axis, and the electrically conductive section of the inner blade axis projects beyond or overhangs the electrically conductive section of the outer blade axis within the wave guide. This advantageously enables, in a particularly compact manner, separate energy or power coupling of microwaves into the blade axes and thus into the blades microwave-connected to the blade axes. The strength of the power coupling into the blade axes is determined by the length of the overhang, e.g.based on the so-called "balun effect".

[0037] If the distance between the two blades along the axis of rotation is motor-adjustable, the length of the overhang, and thus advantageously the strength of microwave power coupling into the inner blade axis, can also be precisely adjusted, because the blade axes are shifted longitudinally relative to each other. Thus, one embodiment allows the length of an overhang of the electrically conductive section of the inner blade axis from the electrically conductive section of the outer blade axis to be adjusted by changing the distance between the two blades along the axis of rotation. A further development allows the inner blade axis to be completely retracted into the outer blade axis, with the length of the overhang being zero.

[0038] This design can be extended analogously to three or even more wings with coaxial wing axes.

[0039] The problem is also solved by a method for operating a household microwave oven equipped with a rotating antenna having at least two blades, wherein, during operation of the household microwave oven, a relative angle between at least two of the blades is adjusted by a motor. The method can be designed analogously to the household microwave oven and has the same advantages.

[0040] It is a configuration in which the absolute angle and / or the relative angle are based on a specification or determination of a product to be treated with microwaves; a distribution of a temperature and / or degree of browning on a surface of a product to be treated with microwaves; an intensity of back-emitted microwaves; and / or a value of one or more operating parameters; The settings are adjusted. This allows the field distribution to be advantageously adapted to different operating conditions, types of microwaved goods (especially cooked food), etc.

[0041] The properties, features and advantages of this invention described above, as well as the manner in which they are achieved, will become clearer and more easily understood in connection with the following schematic description of an exemplary embodiment, which will be explained in more detail in conjunction with the drawings. Fig. 1 shows an oblique view of a rotating antenna according to a first embodiment; Fig. 2A shows a sectional side view of the rotating antenna according to the first embodiment; Fig. 2B shows a sectional side view of the rotating antenna according to a second embodiment; Fig. 3 shows an oblique view of a rotating antenna according to a third embodiment; Fig. 4 shows an oblique view of a section of a rotating antenna according to a fourth embodiment; Fig. 5 shows an oblique view of the vane axes of a rotating antenna according to a fifth embodiment; Fig. 6 shows a top view of the vane axes of the rotating antenna according to the fifth embodiment; Fig. 7 shows a side view of a rotating antenna according to a sixth embodiment; and Fig. 8 shows a sectional side view of a section of a microwave oven with a rotating antenna according to a seventh embodiment.

[0042] Fig. 1Figure 1 shows a rotating antenna 2 of a microwave household appliance 1 in an oblique view, for example in the form of an oven with an additional microwave function. The rotating antenna 2 has a first, "lower" or "front" wing 3 and a second, "upper" or "rear" wing 4, each made of electrically conductive material such as metal. Fig.2A The rotating antenna 2 is shown as a sectional view in side view.

[0043] The first wing 3 extends radially from a cylindrical, inner wing axis 5, while the second wing 4 extends radially from a hollow cylindrical or sleeve-shaped, outer wing axis 6. The two wing axes 5 and 6 are arranged coaxially, with the inner wing axis 5 rotatably mounted on the outer wing axis 6. Both wings 3 and 4 are therefore rotatable about the same axis of rotation R, as indicated by the double arrows. The two wings 3 and 4 are spaced apart from each other along the axis of rotation R.

[0044] The wing axes 5 and 6 can be in or through a microwave guide 52 designed as a hollow body (see Fig. 8) protrude. A variant is shown in which the inner wing axis 5 is made of electrically non-conductive, temperature-resistant, and low-microwave-loss ceramic. The outer wing axis 6 is preferably made of metal to enable the extraction of microwave energy from the waveguide.

[0045] In particular, the relative angle Th between the two wings 3 and 4 can be adjusted by independently rotating the wing axes 5 and 6. A relative angular position of wings 3 and 4 is shown at a relative angle Th of approximately 180° (where wings 3 and 4 are positioned facing away from each other) when viewed along the axis of rotation R. The relative angle Th is determined here with respect to the wing centers, but any other suitable reference point of wings 3 and 4 can also be used.

[0046] The two wings 3 and 4 can be moved simultaneously with the same angular velocity and in the same direction of rotation around the axis of rotation R, thus maintaining their relative angle Th, but changing their position or absolute angle in space. However, the two wings 3 and 4 can also be moved simultaneously with different angular velocities in the same direction of rotation around the axis of rotation R, or moved in opposite directions of rotation, thus changing their relative angle Th to each other. It is also possible to rotate only one of the wings 3 or 4 for a given period of time. The wings can also remain stationary for a given period of time.

[0047] The relative angle Th and / or the absolute angle (including an angular position without adjusting the relative angle Th) of the wings 3, 4 can, for example, be automatically selected based on a specification or determination of a product to be treated with microwaves; a distribution of a temperature and / or degree of browning on a surface of a product to be treated with microwaves; a strength of back-emitted microwaves; a value of one or more operating parameters.

[0048] This also includes the possibility of setting certain sequences of rotation angles or rotation positions of the wings 3, 4, in particular based on the above criteria.

[0049] Both wings 3 and 4 each have a circular sector shape, but possibly with different radii and / or different angle widths.

[0050] In one variant, the wing axes 5 and 6 are connected to their respective drive motors (not shown) for rotation. This allows the angular positions of both wing axes 5 and 6, and thus of the wings 3 and 4 rigidly connected to them, around the axis of rotation R to be individually and completely freely selectable.

[0051] Fig.2B Figure 7 shows a sectional view of a rotating antenna 7 in side view. The rotating antenna 7 is similar in construction to the rotating antenna 2, except that only a rear section 8 of the inner wing axis 5 is made of electrically non-conductive material, in particular electrically non-conductive, temperature-resistant, and low-microwave loss ceramic. A front section 9 of the inner wing axis 5, connected to the front wing 3, is made of electrically conductive material such as stainless steel, copper, or similar. The outer wing axis 6 is now made entirely of electrically non-conductive material.

[0052] Energy extraction in the rotating antenna 7 occurs via the electrically conductive section 9 of the inner wing axis 5. The rear wing 4 can optionally be electrically connected to the electrically conductive section 9, for example via a sliding contact. The advantage of this embodiment lies specifically in the fact that, in practice, the diameter of the wing axes 5, 6 can be reduced compared to the rotating antenna 2 while maintaining the same effect. The reduced diameter of the microwave-emitting axis 5, 6, in turn, allows for a smaller distance to a waveguide wall and waveguide feedthrough towards the cooking chamber 54 (see [reference]). Fig. 8 ) increased. This reduces the risk of sparks.

[0053] Fig. 3Figure 1 shows an oblique view of a rotating antenna 11, which can be installed in the microwave oven 1 in place of the rotating antenna 2. The rotating antenna 11 is similar in design to the rotating antenna 2; however, the front wing 12 is not shaped like a flat circular sector, but rather like a spherical segment bent forward, away from the rear wing 4. As a result, the two wings 12 and 4 are positioned further away from the axis of rotation R than wings 3 and 4, thus reducing the risk of sparking.

[0054] Fig. 4 Figure 1 shows an oblique view of a section of a rotating antenna 21, which can be installed, for example, in place of the rotating antenna 2 in the microwave oven 1. The rotating antenna 21 is similar in design to the rotating antenna 2, except that a stop piece or stop 22 for the rear wing 4 is now provided on the flat side of the front wing 3 facing the rear wing 4.

[0055] If the rear wing 4 is in contact with the stop 22, this can be defined as a relative angle Th = 0°, which corresponds to a zero or rest position. In the rest position, the rear wing 4 is, for example, completely covered by the front wing 3. This results in a particularly high energy transfer into a cooking chamber 54 (see Fig. 8 ) and thus enables the microwaves to be applied to food located in the cooking chamber 58. This is particularly advantageous if the food to be microwaved does not require particularly uniform heating, e.g., in the case of a liquid.

[0056] The stop 22 can be electrically conductive so that, upon mechanical contact with the rear wing 4, it also establishes an electrical connection between the two wings 3 and 4. For this purpose, electrically conductive contact springs 23 can be provided on the stop 22. The electrical conductivity of the stop 22 offers the advantage that, in the rest position, a particularly efficient operating state is established for the microwave generator (not shown), especially for a magnetron, and furthermore, the formation of sparks, for example between the wings 3 and 4, is prevented.

[0057] In this embodiment, the inner wing axis 5 can be driven by a motor, while the outer wing axis 6 or 5 is free-rotating. The stop 22 can be used to adjust the angular position of the rear wing 4 by rotating the inner wing axis 5 and thus the front wing 3, using a single motor. When the rear wing 4 is in contact with the driven front wing 3, it can be driven along with the front wing 3. Subsequent rotation of the front wing 3 in the opposite direction brings the rear wing 4 into contact with the stop 22, and then only the front wing 3 is rotated. In this way, both the relative angle Th between the two wings 3, 4 and the absolute angle can be precisely adjusted.

[0058] However, the outer wing axis 6 can also be the motor-driven wing axis. It is also possible that a rest position exists or is defined at a different relative angle Th, e.g., at a relative angle Th of 180°.

[0059] In general, a resting position or a corresponding relative angle Th can be selected such that, when it is assumed, a particularly high energy output into the cooking chamber is achieved, especially for heating liquids or other loads that do not require particularly uniform heating. Specifically, maximum power can be accessed in this case.

[0060] In general, the rotating antenna can be designed to be adapted to different operating conditions, particularly those specifically tailored to maximizing the energy output of the microwave generator, especially a magnetron, or to increasing the variability of field distributions within the cooking chamber. This is particularly advantageous for inverter microwave ovens, as an inverter can provide adjustable, constant output power.

[0061] In general – and thus also independent of the embodiments described here – the motorized adjustability of the relative angle between the blades around the axis of rotation allows the rotating antenna to be positioned in various angular configurations, which are adapted to different applications. For example, when the blades are arranged directly above one another (e.g., corresponding to a relative angle Th = 0°), microwave energy or power can be radiated into the cooking chamber with a high local energy or power concentration ("focused"). This can manifest itself, for example, in the creation of so-called "hotspots" at specific, especially predetermined, locations in the cooking chamber. This opens up the possibility of introducing a particularly high level of microwave energy into the cooking chamber at the hotspot(s) in a targeted, localized manner.If these hotspots are also located near the axis of rotation, then even when the entire rotating antenna is turned (i.e., when both blades rotate at an angle), only a relatively limited area of ​​the cooking chamber is exposed to high microwave energy. This can be particularly advantageous when heating liquids, as the uniformity of microwave energy distribution within liquids is of secondary importance due to their high thermal conductivity. In this case, it is especially beneficial if the hotspots are generated in a lower area close to the axis of rotation, for example, in an area corresponding to the contents of a typical deep plate or glass. This configuration can also be referred to as the "power configuration." It can be set automatically, for example, when a function such as "heat liquid," "soup," or "hot beverage" is selected on the appliance.

[0062] If, however, a highly uniform distribution of microwaves within the cooking chamber is desired (e.g., by avoiding or sufficiently rapid changes in the position of hotspots), the rotating antenna can be configured in other angles specifically adapted for this purpose. For example, if the blades are positioned opposite each other or facing away from each other with respect to the axis of rotation (e.g., corresponding to a relative angle Th = 180°), microwave energy or power can be radiated into the cooking chamber with fewer, less intense, and / or more widely distributed hotspots compared to Th = 0°. This can be advantageous, for instance, for the uniform heating of solid foods. Rotating the rotating antenna itself (by an absolute angle) then results in a particularly significant change in the field distribution within the cooking chamber over time, leading to a particularly uniform field distribution when integrated over time.

[0063] In general, the relative angle Th can therefore be adjusted, for example, to a selected or identified dish, type of dish or food group.

[0064] Fig. 5 The figure shows in oblique view the two wing axes 32 and 33 of a rotating antenna 31, which can be installed, for example, instead of the rotating antenna 2 in the microwave household appliance 1. Fig. 6Figure 1 shows the wing axes of the rotating antenna 31 in a top view. The two wing axes 32 and 33 are designed similarly to wing axes 5 and 6, respectively, but are connected to each other via a rotary ratchet mechanism 34. The rotary ratchet mechanism 34 mechanically couples the wing axes 32 and 33 in such a way that, in one direction of rotation, only one wing axis 32 rotates with its associated wing, while in the other direction, both wing axes 32 and 33 rotate. This has the advantage that any desired value of the relative angle Th and the absolute angle of the wings 3 and 4 can be set using only one drive motor.

[0065] The rotary ratchet mechanism 34 is designed such that the inner wing axis 32 has several radially projecting, curved pawls 35 along a longitudinal section, which engage in an inner tooth circle of a corresponding annular longitudinal section 36 of the outer wing axis 33. This annular longitudinal section is surrounded by a sleeve- or tube-shaped body 37 that is fixed in space (e.g., rigidly attached to a housing). Several radially projecting, curved pawls 38 extend inwards from the body 37 and engage in an outer tooth circle of the longitudinal section 36.

[0066] When rotating the inner antenna axis 32 clockwise (see in particular Fig. 6 The outer antenna axis 36 is driven by force transmission via the pawls 35. The pawls 38 yield and offer no or no noticeable resistance to movement of the outer antenna axis 36.

[0067] When the inner antenna axis 32 is rotated counterclockwise, no or no noticeable force transmission occurs via the pawls 35. Furthermore, the pawls 38 then block any rotation of the outer wing axis 33, and only the inner wing axis 32 rotates.

[0068] For example, in the first two embodiments (see in particular Fig. 2 The wings 3, 4 or 12, 4 are electrically and microwave-wise separated, since the inner wing axis 5 is made in one piece from an electrically non-conductive material. However, it can be advantageous to have a permanent electrical connection between the wings. This is shown in Figure 1. Fig. 7 In side view, a rotating antenna 41, which can be installed, for example, instead of the rotating antenna 2 in the microwave household appliance 1.

[0069] The rotating antenna 41 is constructed similarly to the rotating antenna 2, but now the wings 3, 4 can be connected to each other via an electrically conductive rotating bearing 42 to 44 - here exemplarily designed in three parts - e.g. a ball bearing or a plain bearing.

[0070] Alternatively, a rotary bearing 42 to 44 can be provided, which maintains electrical isolation of the vanes 3 and 4, but enables microwave coupling. For this purpose, the rotary bearing 42 to 44 can, for example, be designed as a sliding bearing, wherein the upper element 42 and the lower element 44 are electrically conductive and the middle element 43 is electrically non-conductive. This enables capacitive coupling of microwave power between the elements 42 and 44 and thus also between the vanes 3 and 4.

[0071] The middle element 43 advantageously has low sliding friction and can be made of, for example, ceramic or PEEK.

[0072] Elements 42 and 44 can, for example, be ring-shaped or disc-shaped.

[0073] Fig. 8 The diagram shows a section view of a microwave household appliance 1 with a rotating antenna 51, which runs through a microwave guide 52 designed as a waveguide.

[0074] The rotating antenna 51 protrudes through an opening 53 in the microwave guide 52 into the cooking chamber 54 (or alternatively a corresponding anteroom), with the wings 3 and 4 located in the cooking chamber 54. On the side facing away from the cooking chamber 54, the rotating antenna 51 protrudes through another opening from the microwave guide 52 and is surrounded there by a collar 55, e.g. to prevent microwave leakage.

[0075] An inner wing axis 57, arranged coaxially with an outer wing axis 56, is longitudinally displaceable within the outer wing axis 56, for example by means of a suitable adjustment mechanism (not shown). The adjustment mechanism can include a motor or an actuator, e.g., an electric motor, piezoelectric actuator, etc. Depending on the design, the outer wing axis 56 and / or the inner wing axis 57 can be moved or displaced along the axis of rotation R by means of the adjustment mechanism. In particular, the outer wing axis 56 and the inner wing axis 57 can be displaced longitudinally independently, thus enabling height variation of the wings 3 and 4 both absolutely and relative to each other.

[0076] Also not shown is the at least one rotary device located above the collar 55 for rotating the wing axes 56 and 57.

[0077] The outer wing axis 56 has two distinct longitudinal sections 56a and 56b: a first longitudinal section 56a made of electrically conductive material, to which the rear wing 4 is attached, and which projects into a part of the microwave guide 52. Adjoining this, still within the microwave guide 52, is a second longitudinal section 56b made of electrically non-conductive or insulating material, which runs through the collar 55.

[0078] The inner wing axis 53 has an electrically conductive core or liner 58 (e.g., a metallic wire or pin) surrounded by electrically insulating material, which is electrically connected to the associated wing 3 and projects into the microwave guide 52. The liner 58 projects within the microwave guide 52 from the first longitudinal section 56a, which serves as lateral shielding against microwave radiation, with a projection of length d.

[0079] This arrangement enables separate energy or power coupling of the wings 3, 4 to the microwave fields present in the microwave guide 52, whereby energy transport takes place between the first longitudinal section 56a serving as outer conductor and the core 58 serving as inner conductor.

[0080] The adjustment mechanism allows the distance between the two wings 3 and 4 to be precisely adjusted along the axis of rotation R. Adjusting the distance between wings 3 and 4 correspondingly changes their length d. This design offers the advantage that the height of wings 3 and 4 can be varied both absolutely and relative to each other, thus enabling a particularly diverse variation in the field distribution within the cooking chamber 54. According to the so-called balun effect, the length d determines the energy input to the different wings 3 and 4.

[0081] Of course, the present invention is not limited to the embodiments shown. The figures only describe in detail rotary antennas having two wings whose axes are arranged coaxially. However, a rotary axis can also have more than two axes, and the axes need not be arranged coaxially. For example, it is possible to arrange two or more rotatable axes parallel to each other and to mount these axes as a group so that they can rotate, e.g., by means of a rotating ring that holds the axes rotatably.

[0082] In general, "ein", "eine", etc. can be understood to mean singular or plural, especially in the sense of "at least one" or "one or more", etc., unless this is explicitly excluded, e.g. by the expression "exactly one", etc.

[0083] A numerical specification can also include exactly the specified number as well as a normal tolerance range, unless this is explicitly excluded. Reference symbol list

[0084] 1 Microwave appliance 2 Rotating antenna 3 Front wing 4 Rear wing 5 Inner wing axis 6 Outer wing axis 7 Rotating antenna 8 Rear section of inner wing axis 9 Front section of inner wing axis 11 Rotating antenna 12 Front wing 21 Rotating antenna 22 Stop 23 Contact spring 31 Rotating antenna 32 Inner wing axis 33 Outer wing axis 34 Rotary ratchet mechanism 35 Latch 36 Longitudinal section 37 Body 38 Latch 41 Rotating antenna 42 First element of a pivot bearing 43 Second element of a pivot bearing 44 Third element of a pivot bearing 51 Rotating antenna 52 Microwave guide 53 Opening 54 Cooking chamber 55 Collar 56 Outer wing axis 56a Longitudinal section of the outer wing axis 56b Longitudinal section of the outer wing axis 57Inner wing axis 58Soul dLength of overhang RRotation axis ThRelative angle

Claims

1. Household microwave appliance (1), having a rotary antenna (2; 7; 11; 21; 31; 41; 51) with at least two wings (3, 4; 12, 4) rotatable about a common axis of rotation (R), wherein a relative angle (Th) between at least two of these wings (3, 4; 12, 4) is adjustable in a motor-driven manner about the axis of rotation (R), characterised in that at least two wings (3, 4; 12, 4) can be rotated independently of one another.

2. Household microwave appliance (1) according to claim 1, wherein each of the wings (3, 4; 12, 4) is connected to a respective drive motor for its rotatability by way of a respective wing axis (5, 6; 56, 57).

3. Household microwave appliance (1) according to claim 1, wherein at least two wings (3, 4; 12, 4) can be rotated by way of wing axes (5, 6; 32; 33; 56, 57) arranged coaxially with respect to one another and wherein the wing axes (32, 33) of two wings (3, 4; 12, 4) are connected to one another by way of a rotary ratchet mechanism (34).

4. Household microwave appliance (1) according to claim 1, wherein at least two wings (3, 4; 12, 4) can be rotated by means of the same motor about a transmission with an axis-dependent different gear ratio.

5. Household microwave appliance (1) according to one of claims 2 or 4, wherein two of the wings (3, 4) can be rotated with a different angular speed in the same direction of rotation about the axis of rotation (R) .

6. Household microwave appliance (1) according to claim 2, wherein two of the wings (3, 4) can be rotated about the axis of rotation (R) in the opposite direction of rotation.

7. Household microwave appliance (1) according to one of the preceding claims, wherein a distance of at least two of the wings (3, 4; 12, 4) relative to one another can be adjusted in a motor-driven manner along the axis of rotation (R)8. Household microwave appliance (1) according to claim 7, wherein the rotary antenna (51) has two wings (3, 4) with wing axes (56, 57) arranged coaxially, each of which has an electrically conductive section (56a, 58), connected in terms of microwave technology to the wings (3, 4), which projects into a part of a microwave guide (52), wherein the electrically conductive section (56a) of the outer wing axis (56) is embodied as a lateral shield for a corresponding electrically conductive section (58) of the inner wing axis (57), and the electrically conductive section (58) of the inner wing axis (57) within the microwave guide (52) projects beyond the electrically conductive section (56a) of the outer wing axis (56), wherein a length (d) of a projection of the electrically conducting section (58) of the inner wing axis (57) from the electrically conducting section (56a) of the outer wing axis (56) can be adjusted by adjusting the distance between the two wings (3, 4) along the axis of rotation (R).

9. Household microwave appliance (1) according to one of the preceding claims, wherein the rotary antenna (2; 7; 11; 21; 31; 41; 51) has more than two wings (3, 4; 12, 4).

10. Method for operating a household microwave appliance (1) according to one of the preceding claims, which is equipped with a rotary antenna (2; 7; 11; 21; 31; 41; 51) with at least two wings (3, 4, 12, 4), wherein a relative angle (Th) between at least two of the wings (3, 4; 12, 4) is adjusted in a motor-driven manner during operation of the household microwave appliance (1).

11. Method according to claim 10, wherein the relative angle (Th) is set on the basis of - a specification or determination of a product to be treated with microwaves; - a distribution of a temperature and / or a degree of browning on a surface of the product to be treated with microwaves; - a strength of backscattered microwaves; - a value of one or more operating parameters.

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