DOMESTIC MICROWAVE DEVICE WITH ROTARY ANTENNA

Abstract

A household microwave appliance includes a rotary antenna having a plurality of wings rotatable about a common axis of rotation, with a relative angle between at least two of the plurality of wings being adjustable in a motor-driven manner about the axis of rotation.

Claims

1-13. (canceled)

14. A household microwave appliance, comprising a rotary antenna including a plurality of wings rotatable about a common axis of rotation, with a relative angle between at least two of the plurality of wings being adjustable in a motor-driven manner about the axis of rotation.

15. The household microwave appliance of claim 14, wherein the at least two wings are rotatable independently of one another.

16. The household microwave appliance of claim 14, wherein the at least two wings are rotatable by wing axes arranged coaxially with respect to one another.

17. The household microwave appliance of claim 16, further comprising a rotary ratchet mechanism configured to connect the at least two wing axes of the at least two wings to one another.

18. The household microwave appliance of claim 14, wherein the at least two wings are rotatable by a same motor via a transmission with an axis-dependent different gear ratio.

19. The household microwave appliance of claim 14, wherein one of the at least two wings includes a stop for another one of the at least two wings.

20. The household microwave appliance of claim 19, wherein the stop is an electrically conductive stop.

21. The household microwave appliance of claim 14, wherein the at least two wings are spaced relative to one another by a distance which is adjustable in a motor-driven manner along the axis of rotation.

22. The household microwave appliance of claim 16, wherein the wing axes have each an electrically conductive section, which is connected in terms of microwave technology to the respective one of the at least two wings, said electrically conductive section projecting into a part of a microwave guide, wherein the at least two wing axes define an outer wing axis and an inner wing axis, with the electrically conductive section of the outer wing axis being embodied as a lateral shield for the electrically conductive section of the inner wing axis, and with the electrically conductive section of the inner wing axis within the microwave guide projecting beyond the electrically conductive section of the outer wing axis.

23. The household microwave appliance of claim 22, wherein a length of a projection of the electrically conducting section of the inner wing axis from the electrically conducting section of the outer wing axis is adjustable by adjusting a distance between the at least two wings along the axis of rotation.

24. The household microwave appliance of claim 14, wherein the plurality of wings of rotary antenna is precisely two wings.

25. A method for operating a household microwave appliance, comprising adjusting a relative angle between at least two wings of a rotary antenna of the household microwave appliance in a motor-driven manner during operation of the household microwave appliance.

26. The method of claim 25, wherein the relative angle 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, or a value of one or more operating parameters.

Description

[0045] The afore-described properties, features and advantages of this invention and the manner in which these are achieved will become clearer and more intelligible in conjunction with the following schematic description of an exemplary embodiment which is explained in more detail in conjunction with the drawings.

[0046] FIG. 1 shows an oblique view of a rotary antenna according to a first exemplary embodiment;

[0047] FIG. 2A shows a sectional representation in the side view into the rotary antenna according to the first exemplary embodiment;

[0048] FIG. 2B shows a sectional representation in the side view into the rotary antenna according to a second exemplary embodiment;

[0049] FIG. 3 shows an oblique view of a rotary antenna according to a third exemplary embodiment;

[0050] FIG. 4 shows an oblique view of a cutout from a rotary antenna according to a fourth exemplary embodiment;

[0051] FIG. 5 shows an oblique view of wing axes of a rotary antenna according to a fifth exemplary embodiment;

[0052] FIG. 6 shows a top view of the wing axes of the rotary antenna according to the fifth exemplary embodiment;

[0053] FIG. 7 shows a side view of a rotary antenna according to a sixth exemplary embodiment; and

[0054] FIG. 8 shows a sectional representation in a side view of a cutout from a microwave household appliance with a rotary antenna according to a seventh exemplary embodiment.

[0055] FIG. 1 shows an oblique view of a rotary antenna 2 of a microwave household appliance 1 in the form e.g. of an oven with additional microwave function. The rotary antenna 2 has a first “lower” or “front” wing 3 and a second “upper” or “rear” wing 4, which consist in each case of electrically conductive material such as metal. FIG. 2A shows the rotary antenna 2 as a sectional representation in a side view.

[0056] The first wing 3 projects radially from a cylindrical, inner wing axis 5, while the second wing 4 projects radially from a hollow cylinder-shaped or sleeve-shaped, outer wing axis 6. The two wing axes 5 and 6 are arranged coaxially relative to one another, wherein the inner wing axis 5 is arranged rotatably in the outer wing axis 6. Both wings 3 and 4 can therefore be rotated about the same axis of rotation R, as indicated by the double arrows. The two wings 3 and 4 are arranged at a distance from one another along the axis of rotation R.

[0057] The wing axes 5 and 6 can project into or through a microwave guide 52 (see FIG. 8) embodied as a hollow body. A variant in which the inner wing axis 5 is embodied from electrically non-conductive, temperature-resistant and low-loss microwave ceramic is shown. The outer wing axis 6 preferably consists of metal, in order to be able to couple microwave energy out from the hollow conductor.

[0058] In particular, a relative angle Th of the two wings 3 and 4 relative to one another can be set by independent rotation of the wing axes 5 and 6. A relative angular position of the wings 3 and 4 is shown with a relative angle Th of approx. 180° (in which the wings 3 and 4 are arranged facing away from one another), with a view along the axis of rotation R. The relative angle Th is determined here in respect of the wing centers, but can however also use any other suitable reference point of the wings 3, 4.

[0059] The two wings 3, 4 can be moved simultaneously at the same angular speed in the same direction of rotation about the axis of rotation R, as a result of which their relative angle Th is retained but their position or their absolute angle in the space changes. The two wings 3, 4 can however also be moved simultaneously with a different angular speed in the same direction of rotation about the axis of rotation R or in the opposite direction of rotation, as a result of which their relative angle Th changes with respect to one another. It is also possible to rotate just one of the wings 3 or 4 during a duration. The wings can also remain stationary during a duration.

[0060] 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 be selected automatically, for instance, on the basis of

[0061] a specification or determination of a product to be treated with microwaves;

[0062] a distribution of a temperature and/or a degree of browning on a surface of a product to be treated with microwaves;

[0063] a strength of backscattered microwaves;

[0064] a value of one or more operating parameters.

[0065] This also involves the possibility of adjusting specific sequences of angles of rotation or rotational positions of the wings 3, 4, in particular on the basis of the above criteria.

[0066] Both wings 3 and 4 here have a circular sector shape, in each case, but possibly with a different radius and/or different angular width.

[0067] In one variant, the wing axes 5 and 6 are connected for their rotation with respective drive motors (top fig.). As a result, the angular positions of both wing axes 5 and 6 and thus the wings 3 or 5 connected fixedly or rigidly therewith about the axis of rotation R can be selected individually and completely freely.

[0068] FIG. 2B shows a sectional representation in the side view of a rotary antenna 7. The rotary antenna 7 is designed similarly to the rotary antenna 2, wherein only a rear section 8 of the inner wing axis 5 is however embodied from electrically non-conductive material, in particular from electrically non-conductive, temperature-resistant and low-loss microwave ceramic. A front section 9 of the inner wing axis 5, connected to the front wing 3, conversely consists of electrically conductive material such as stainless steel, copper or suchlike. The outer wing axis 6 now consists entirely of electrically non-conductive material.

[0069] The energy is coupled out in the rotary antenna 7 by way of the electrically conductive section 9 of the inner wing axis 5. In this regard the rear wing 4 can optionally be connected in an electrically conducting manner with the electrically conductive section 9, for instance by way of a sliding contact. The advantage of this exemplary embodiment consists especially in that the diameter of the wing axes 5, 6 can in practice be reduced with the same effect in relation to the rotary antenna 2. On account of the reduced diameter of the axis 5, 6 channeling out the microwaves, a distance from a hollow conductor wall and hollow conductor feedthrough can in turn be increased in the direction of the cooking chamber 54 (see FIG. 8). This reduces the risk of spark discharges.

[0070] FIG. 3 shows an oblique view of a rotary antenna 11, which can be installed in the microwave household appliance 1 instead of the rotary antenna 2. The rotary antenna 11 is embodied similarly to the rotary antenna 2, but the front wing 12 now does not have the shape of a flat circular sector, but instead a spherical shell segment which bends forward or away from the rear wing 4. As a result, the two wings 12 and 4 with a larger distance from the axis of rotation R have a greater distance than the wings 3 and 4, which reduces the risk of a spark discharge.

[0071] FIG. 4 shows an oblique view of a cutout from a rotary antenna 21, which can be installed in the microwave household appliance 1 instead of the rotary antenna 2. The rotary antenna 21 is embodied similarly to the rotary antenna 2, wherein a stop piece or stop 22 for the rear wing 4 is now present on the flat side of the front wing 3 which faces the rear wing 4.

[0072] If the rear wing 4 is located as far as the stop with the stop 22, this can be defined as a relative angle Th=0°, which corresponds to a zero or rest position. By way of example, in the rest position, the rear wing 4 is covered completely by the front wing 3. As a result, a particularly high energy output into a cooking chamber 54 (see FIG. 8) and thus a product located in the cooking chamber 58 is enabled. This is particularly advantageous if the product to which microwaves are to be applied does not require a particularly uniform heating, e.g. in the case of a presence of liquid.

[0073] The stop 22 can be embodied to be electrically conductive, so that with mechanical contact with the rear wing 4, an electrical connection is also established between the two wings 3 and 4. To this end, electrically conductive contact springs 23 may be present on the stop 22. The electrical conductivity of the stop 22 is advantageous in that a particularly effective operating state is produced in the rest position for the microwave generator (top fig.), in particular for a magnetron, and furthermore the formation of sparks, for instance between the wings 3 and 4, is prevented.

[0074] In this exemplary embodiment, the inner wing axis 5 can be driven in a motor-driven manner, while the outer wing axis 6 or 5 is freely rotating. The stop 22 can be used to set the angular position also of the rear wing 4 by means of a single motor by rotating the inner wing axis 5 and thus the front wing 3. The rear wing 4 can then, if it is in contact with the driven front wing 3, be carried along with the front wing 3, whereas when the front wing 3 is subsequently rotated in the reverse direction of rotation, the rear wing 4 disengages from the stop 22 and only the front wing 3 is still rotated. Therefore the relative angle Th between the two wings 3, 4 and also the absolute angle can be targetedly adjusted.

[0075] However, the outer wing axis 6 can basically also be the motor-driven wing axis. Similarly it is possible for a rest position to consist of or be defined with another relative angle Th, e.g. with a relative angle Th of 180°.

[0076] A rest position or a corresponding relative angle Th can generally be selected so that upon its assumption a particularly high energy output into the cooking chamber is achieved, in particular to heat up liquid or another load, which does not require a particularly uniform heating. In particular, in this case, the maximum power can be called up.

[0077] In general, the rotary antenna can be embodied so that it is attuned to different operating states, in particular to operating states which are either adjusted in a targeted manner to a maximum energy output of the microwave generator, in particular a magnetron, or to an increased variability of field distributions in the cooking chamber. This is particularly advantageous for inverter microwave appliances, since an inverter can provide adjustable, constant output powers.

[0078] Generally, and thus also independently of the exemplary embodiments described here, the motor-driven adjustability of the relative angle between the wings about the axis of rotation can bring the rotary antenna into different angle configurations, which are adjusted to different applications. Therefore microwave energy or power with a high local energy or power concentration can be irradiated (“focused”) into the cooking chamber, for instance, if the wings are arranged directly one above the other (e.g. corresponding to a relative angle Th=0°). This can be expressed for instance so that points in the cooking chamber, known as “hotspots” are generated at specific, in particular predetermined points. As a result, this makes it possible to targetedly locally introduce particularly high microwave energy into the cooking chamber at the points of the hotspot(s). If these hotspots are also arranged close to the axis of rotation, with a rotation of the rotary antenna as a whole (and with an angular rotation of both wings), high microwave energy is applied to only a comparatively limited spatial region of the cooking chamber. This can be particularly advantageous if liquid is to be heated. This is because a uniformity of the distribution of the microwave energy in the liquid only plays a subordinate role on account of its high thermal conductivity. It is particularly advantageous in this case if the hotspots are generated in a lower spatial region disposed close to the axis of rotation, e.g. a spatial region which corresponds to a content of a plate or glass of a typical depth. This configuration can also be referred to as “power configuration”. It can be automatically set, for instance, if an application such as “Heat liquid”, “Soup”, “Hot beverage” inter alia is selected on the appliance.

[0079] If in contrast a high uniform distribution of the microwaves in the cooking chamber is to be achieved (e.g. by avoiding or sufficiently rapidly changing the position of the hotspot), the rotary antenna can be brought into other angular configurations, which are adjusted to such a purpose. Therefore if the wings face one another or are arranged facing away from one another in respect of the axis of rotation (e.g. according to a relative angle Th=180°), microwave energy or power with less, less significant and/or spatially further distributed hotspots, compared with Th=0°, can be irradiated into the cooking chamber. This can be advantageous e.g. for uniform heating of solid foods. With a rotation of the rotary antenna as such (about an absolute angle), the field distribution in the cooking chamber is then changed particularly significantly over time, so that a particularly uniform field distribution is produced in a temporally integrated manner.

[0080] In general, the relative angle Th can therefore be adjusted to a selected or identified food, type of dish or group of dishes.

[0081] FIG. 5 shows an oblique view of the two wing axes 32 and 33 of a rotary antenna 31, which can be installed in the microwave household appliance 1 e.g. instead of the rotary antenna 2. FIG. 6 shows the wing axes of the rotary antenna 31 in a top view. The two wing axes 32 and 33 are embodied similarly to the wing axes 5 or 6, but are connected to one another by way of a rotary ratchet mechanism 34. The rotary ratchet mechanism 34 causes the wing axes 32 and 33 to be mechanically coupled so that in one direction of rotation only one wing axis 32 rotates with the associated wing, in the other direction however both wing axes 32 and 33. This is advantageous in that by providing just one drive motor, it is possible to set any value of the relative angle Th and the absolute angle of the wings 3, 4.

[0082] The rotary ratchet mechanism 34 is embodied so that on a longitudinal section the inner wing axis 32 has a number of radially projecting, curved latches 35, which engage in an inner toothed circle of a corresponding, circular ring-shaped longitudinal section 36 of the outer wing axis 33. This circular ring-shaped longitudinal section is surrounded by a sleeve or pipe-shaped, fixedly arranged body (e.g. rigidly attached to a housing). A number of radially projecting, curved latches 38, which engage into an outer toothed circle of the longitudinal section 36, move inward from the body.

[0083] When the inner antenna axis 32 is rotated in the clockwise direction (see in particular FIG. 6), the outer antenna axis 36 is carried out over the latches 35 by way of force transmission. In this process, the latches 38 yield and offer no or no noticeable resistance to counteract a movement of the outer antenna axis 36.

[0084] When the inner antenna axis 32 is rotated counterclockwise, conversely no force or no noticeable force is transmitted by way of the latches 35. Moreover, the latches 38 then block a rotational movement of the outer wing axis 33, and only the inner wing axis 32 rotates.

[0085] For instance, in the first two exemplary embodiments (see in particular FIG. 2), the wings 3, 4 or 12, 4 are separated electrically and in terms of microwave technology, since the inner wing axis 5 is embodied in one piece from an electrically non-conductive material. However, provision can advantageously be made for a permanent electrical connection to exist between the wings. To this end, FIG. 7 shows a side view of a rotary antenna 41, which can be installed in the microwave household appliance 1 instead of the rotary antenna 2, for instance.

[0086] The rotary antenna 41 is designed similarly to the rotary antenna 2, wherein the wings 3, 4 can now be connected to one another by way of an electrically conductive rotary bearing 42 to 44, embodied here in three pieces by way of example, e.g. a spherical bearing or sliding bearing.

[0087] Alternatively, a rotary bearing 42 to 44 can be provided, which maintains an electrical separation of the wings 3, 4, but enables a coupling in terms of microwave technology. To this end, the rotary bearing 42 to 33 can be embodied as a sliding bearing, for instance, wherein the upper element 42 and the lower element 44 are embodied to be electrically conductive and the middle element 43 is embodied to be electrically non-conducting. A capacitive coupling of microwave power between the elements 42 and 44 and thus also between the wings 3 and 4 is therefore enabled.

[0088] The middle element 43 advantageously has a minimal sliding friction and can consist of ceramic or PEEK, for instance.

[0089] The elements 42 and 44 can be molded in a ring or disk-shaped manner, for instance.

[0090] FIG. 8 shows as a sectional representation in a side view a cutout from the microwave household appliance 1 with a rotary antenna 51, which runs through a microwave guide 52 embodied as a hollow conductor.

[0091] The rotary antenna 51 projects through an opening 53 in the microwave guide 52 into the cooking chamber 54 (or alternatively a corresponding front space), wherein the wings 3 and 5 are located in the cooking chamber 54. On the side facing away from the cooking chamber 54, the rotary antenna 51 projects through a further opening out from the microwave guide 52, and is surrounded there by a collar 55, e.g. in order to prevent microwaves from leaking.

[0092] An inner wing axis 57 arranged coaxially in respect of an outer wing axis 56 is arranged so as to be longitudinally displaceable in the outer wing axis 56, e.g. by means of a suitable adjustment mechanism (top fig.). The adjustment mechanism can have a motor or an actuator, e.g. an electric motor, piezo actuator etc. The adjustment mechanism can be used to move or displace the outer wing axis 56 and/or the inner wing axis 57 along the axis of rotation R depending on the structural design. In particular, the outer wing axis 56 and the inner wing axis 57 can be displaced individually longitudinally, as a result of which a height variation in the wings 3 and 4 is enabled both absolutely and also relatively to one another.

[0093] The at least one rotating facility, present above the collar 55, for rotating the wing axes 56 and 57 is also not shown.

[0094] The outer wing axis 56 has two different longitudinal sections 56a and 56b, namely a first longitudinal section 56a with or made from electrically conductive material, to which the rear wing 4 is fastened, and which projects into a part of the microwave guide 52. A second longitudinal section 56b made from electrically non-conductive or insulating material, which runs through the collar 55, is connected thereto in the microwave guide 52.

[0095] The inner wing axis 53 has an electrically conductive core 58 surrounded by electrically insulating material (e.g. a metallic wire or pin), which is connected electrically to the associated wing 3, and projects into the microwave guide 52. The core 58 protrudes with a projection of length d within the microwave guide 52 made from the first longitudinal section 56a, which is used as a lateral shield against microwave radiation.

[0096] This arrangement makes possible a separate energy or power coupling of the wings 3, 4 to the microwave fields present in the microwave guide 52, wherein energy is transported between the first longitudinal section 56a serving as an outer conductor and the core 58 serving as the inner conductor.

[0097] By means of the adjustment mechanism, the distance between the two wings 3 and 4 can be targetedly adjusted along the axis of rotation R. The length d changes analogously with the adjustment of the distance between the wings 3 and 4. This variant has the advantage that a height variation of the wings 3 and 4 is possible both absolutely and also relatively to one another, as a result of which, in turn, a particularly versatile variation of the field distribution within the cooking chamber 54 is enabled. In this regard, according to the so-called Balun effect, the length d determines the energy input onto the different wings 3, 4.

[0098] The present invention is naturally not restricted to the exemplary embodiments shown. Only rotary antennas which have two wings, the wing axes of which are arranged coaxially with respect to one another, are therefore described in the figures. However, an axis of rotation can also have more than two wing axes, and the wing axes do not need to be arranged coaxially with respect to one another. It is therefore possible, for instance, to arrange two or more in parallel with one another about rotatable wing axes and to arrange these wing axes rotatably as a group, e.g. by means of a ring mount keeping the wing axes rotatable.

[0099] In general, “a”, “an”, etc. can be understood as singular or plural, in particular in the sense of “at least one” or “one or more”, etc., provided this is not explicitly excluded. e.g. by the expression “precisely one”, etc.

[0100] A numerical value can also include the given value as well as a typical tolerance range, provided this is not explicitly excluded.

LIST OF REFERENCE CHARACTERS

[0101] 1 microwave household appliance [0102] 2 rotary antenna [0103] 3 front wing [0104] 4 rear wing [0105] inner wing axis [0106] 6 outer wing axis [0107] 7 rotary antenna [0108] 8 rear section of the inner wing axis [0109] 9 front section of the inner wing axis 11 rotary antenna [0110] 12 front wing [0111] 21 rotary antenna [0112] 22 stop [0113] 23 contact spring [0114] 31 rotary antenna [0115] 32 inner wing axis [0116] 33 outer wing axis [0117] 34 rotary ratchet mechanism [0118] latch [0119] 36 longitudinal section [0120] 37 body [0121] 38 latch [0122] 41 rotary antenna [0123] 42 first element of a rotary bearing [0124] 43 second element of a rotary bearing [0125] 44 third element of a rotary bearing [0126] 51 rotary antenna [0127] 52 microwave guide [0128] 53 opening [0129] 54 cooking chamber [0130] 55 collar [0131] 56 outer wing axis [0132] 56a longitudinal section of the outer wing axis [0133] 56b longitudinal section of the outer wing axis [0134] 57 inner wing axis [0135] 58 core [0136] d length of the projection [0137] R axis of rotation [0138] Th relative angle